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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

    Energy Technology Data Exchange (ETDEWEB)

    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. Miopatia miotubular: estudo clinico, eletrofisiologico e histologico de um caso

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    José L. Alonso

    1981-12-01

    Full Text Available São apresentados os resultados dos exames clínicos, eletrofisiológicos e do estudo do ponto motor, da imunofluorescência, da histoquímica e da ultrami-croscopia da biópsia muscular de um caso de miopatia miotubular. São discutidos estes resultados em relação aos achados de 56 casos desta moléstia consignados na literatura até 1978, sendo dada enfase à etiopatogenia.

  3. Inflamação esclerosante idiopática da órbita: estudo clinico-patológico

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    Lívia Maria Nossa Moitinho

    2012-10-01

    Full Text Available OBJETIVO: Descrever oito casos de inflamação esclerosante idiopática da órbita, incluindo a análise clínica e histopatológica. MÉTODOS: Estudo retrospectivo através do livro de registros do Laboratório de Patologia Ocular (LPO do Hospital Universitário Professor Edgard Santos, Universidade Federal da Bahia, no período de 1974 a 2010. Além de revisão de lâminas de todos os casos e das imagens clínicas e de exames complementares recuperadas dos arquivos pessoais dos autores. RESULTADOS: Dentre o total de espécimes submetidos ao LPO (7546 apenas 8 casos receberam diagnóstico final de inflamação esclerosante idiopática da órbita. Em todos os casos houve piora ou deterioração da acuidade visual à despeito do tratamento, com exceção de um, que permaneceu com a mesma visão (percepção luminosa. Em nosso estudo, observamos envolvimento orbitário predominantemente apical. Todos os nossos pacientes foram submetidos à biópsia incisional com finalidade diagnóstica. Também submeteram-se à corticoterapia e em um caso foi associada à radioterapia anti-inflamatória; em dois destes casos, foi utilizado também ciclofosfamida. Dois pacientes com acuidade final sem percepção luminosa tiveram que ser submetidos à exenteração parcial da órbita para tratamento de dor incontrolável. CONCLUSÃO: A inflamação esclerosante orbitária idiopática permanece como uma doença pouco conhecida, de péssimo prognóstico visual.

  4. Atrofia muscular proximal neurogenica hereditaria (doença de Wohlfart-Kugelberg-Welander: estudo clinico, eletromiografico e anatomo-patologico de 3 irmãos

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    Marcos R. G. de Freitas

    1976-03-01

    Full Text Available Os autores relatam os casos de três irmãos com fraqueza e amiotrofia proximal dos membros de início na infância. Os estudos eletromiográficos e de biópsias musculares revelaram alterações do tipo neurogênico de permeio com alterações miogênicas. Fazem consideração sobre esta singular associação, considerando as alterações do tipo miopático como secundárias à denervação de longa duração. O estudo histopatológico medular, em um dos pacientes, revelou degeneração das células motoras das pontas anteriores, constituindo, assim, o 4.° estudo de autópsia da doença de Wohlfart-Kugelberg-Welander, na literatura.

  5. Corneal Abrasions

    Science.gov (United States)

    ... and lead to a serious condition called a corneal ulcer . That's why it's important to see a doctor to get a corneal abrasion checked out. What Causes a Corneal ... and land on your cornea, tears help to wash the particles away. Sometimes, ...

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

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    Paulo R. de Brito-Marques

    1992-06-01

    Full Text Available 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 respiratória. O diagnóstico foi confirmado pelo estudos do LCR, eletrofisiológicos, radiológicos e pelos achados de necropsia (cérebro e glândulas adrenais.

  7. Estudo clinico da epilepsia catamenial: tipos clinicos das crises epilepticas

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    Arthur Oscar Schelp

    1983-06-01

    Full Text Available Foram atendidas 431 pacientes epilépticas com idades acima de 10 anos, no período de fevereiro a julho de 1981 no ambulatório de neurologia do H.C.F.M.R.P. Destas, foram selecionadas 119 pacientes com idade de 13 a 45 anos e/ou fluxo menstrual periódico e pelo menos uma crise epiléptica ao mês. As pacientes foram separadas em dois grupos, o primeiro constituído de 36 pacientes com diagnóstico de epilepsia catamenial e o segundo com 83 pacientes que apresentavam epilepsia não catamenial. Determinamos um coeficiente de prevalência de 105,9/1000 para a epilepsia catamenial. Classificamos os tipos clínicos de crises epilépticas ocorridas em pacientes com epilepsia catamenial e comparamos com as ocorridas em pacientes na menacme.

  8. Machining with abrasives

    CERN Document Server

    Jackson, Mark J

    2011-01-01

    Abrasive machining is key to obtaining the desired geometry and surface quality in manufacturing. This book discusses the fundamentals and advances in the abrasive machining processes. It provides a complete overview of developing areas in the field.

  9. Ultrasonic magnetic abrasive finishing

    Institute of Scientific and Technical Information of China (English)

    LU Ya-ping; MA Ji; ZHANG Jun-qiang; WANG Long-shan

    2006-01-01

    Put forward a new kind of polishing method, ultrasonic magnetic abrasive finishing (UMAF), and studied its mechanism of improving polishing efficiency. By analyzing all kind of forces acting on single abrasive particle in the polishing process and calculating the size of the composition of forces, get the conclusion that UMAF will enhance the efficiency of the normal magnetic abrasive finishing(MAF) due to the ultrasonic vibration increases the cutting force and depth. At last the idea of designing the UMAF system based on numerical control milling machine is put forward which is convenient to setup and will accelerate the practical application of MAF.

  10. Contact air abrasion.

    Science.gov (United States)

    Porth, R

    1999-05-01

    The advantages of contact air abrasion techniques are readily apparent. The first, of course, is the greatly increased ease of use. Working with contact also tends to speed the learning curve by giving the process a more natural dental feel. In addition, as one becomes familiar with working with a dust stream, the potential for misdirecting the air flow is decreased. The future use of air abrasion for deep decay removal will make this the treatment of choice for the next millennium.

  11. 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

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    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

  12. Estudo genetico-clinico de glaucoma congenito primario

    OpenAIRE

    Andrea Trevas Maciel-Guerra

    1989-01-01

    Resumo: O Glaucoma Congênito Primário (GCP) é uma entidade genética heterogênea, geralmente considerada distinta da Megalocórnea e do glaucoma congênito de manifestação tardia ou juvenil. A fim de detectar indicações da heterogeneidade genética do GCP a nível clínico, foram examinados 67 portadores dessa anomalia, dos quais se obtiveram dados anamnésticos e de exame oftalmológico. Os resultados da análise se segregação, bem como a alta freqüência de consangüinidade observada nessa amostra ind...

  13. Estados pre-leucemicos na infancia : estudo clinico e hematologico

    OpenAIRE

    Luiz Fernando Lopes

    1994-01-01

    Resumo: Fizemos uma avaliação retrospectiva de 18 crianças com pré-leucemia entre 320 pacientes que foram encaminhados ao Departamento de Pediatria do Hospital A.C.Camargo - São Paulo - entre janeiro de 1984 a dezembro de 1991 com diagnóstico prévio de leucemia para ser confirmado ou afastado. Leucemia linfocítica aguda foi confirmada em 227 pacientes e leucemia não linfocítica aguda em 54. Entre os 18 pacientes que foram classificados com pré-leucemia 8 apresentavam síndrome mielodisplásica,...

  14. Distrofia muscular congênita estudo clinico de 17 pacientes

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    A. S. B. Oliveira

    1991-09-01

    Full Text Available Descrevemos 17 pacientes (12m, 5f com idades que variaram de 1 a 24 anos (mediana 6 anos com distrofia muscular congênita (DMC, que foram estudados do ponto de vista genético, clínico, laboratorial, eletrofisiológico e anátomo-patológico. A apresentação segundo a herança foi da forma esporádica (76,5% ou possivelmente autossômica recessiva (23,5%. A diminuição da movimentação fetal intra-uterina foi referida em 57% dos casos, hipotonia neonatal em 82% e retardo no desenvolvimento motor em 88,2%. Fraqueza muscular, diminuição dos reflexos profundos e contraturas articulares estavam presentes em todos os casos. A piora na função motora estava muito relacionada ao aumento ou aparecimento de novas retrações articulares. A CK nunca ultrapassou valores acima de 8 vezes o normal. O ENMG foi de padrão miopático em 73,3%, neuropático em 13,3% e normal em 13,3% dos casos. Aspectos tomográficos com hipodensidade da substância branca subcortical foram vistos em 8 casos. Ao tratamento impôs-se fisioterapia adequada e cirurgia corretiva das deformidades articulares. Novas contraturas desenvolveram-se mais tarde e estavam relacionadas freqüentemente a fisioterapia insuficiente.

  15. Abrasion of ultrafine WC-Co by fine abrasive particles

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Abrasive wear of a series of WC-(5%-14%, mass fiaction)Co hardmetals was investigated employing coarse and fine SiC abrasive under two-body dry abrasion conditions with pin-on-disc and edge-on-disc test arrangements. Unexpectedly, it is found that submicron grades demonstrate substantially higher wear rates comparing with the coarse grades if fine abrasive is utilized in pin-on-disc tests. Such a behavior is attributed to changes in a ratio of abrasive size to size of hard phase as finer abrasive is used.The edge-on-disc test demonstrates that edge wear may be described in two stages with the highest wear rates at the beginning stage.This behavior is associated with a transition of wear mechanisms as edge is wider due to wear. Compared with the ultrafine grades of the same Co content, the coarse grades demonstrate higher wear rates at the beginning, but lower wear rates at the final stage. Wear rates and mechanisms observed at final stage correlate well to the results observed for pin-on-disc tests employing fine abrasive.

  16. Patching for corneal abrasion.

    Science.gov (United States)

    Lim, Chris H L; Turner, Angus; Lim, Blanche X

    2016-07-26

    Published audits have demonstrated that corneal abrasions are a common presenting eye complaint. Eye patches are often recommended for treating corneal abrasions despite the lack of evidence for their use. This systematic review was conducted to determine the effects of the eye patch when used to treat corneal abrasions. The objective of this review was to assess the effects of patching for corneal abrasion on healing and pain relief. We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register) (2016, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE (January 1946 to May 2016), EMBASE (January 1980 to May 2016), Latin American and Caribbean Health Sciences Literature Database (LILACS) (January 1982 to May 2016), System for Information on Grey Literature in Europe (OpenGrey) (January 1995 to May 2016), the ISRCTN registry (www.isrctn.com/editAdvancedSearch), ClinicalTrials.gov (www.clinicaltrials.gov) and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 9 May 2016. We also searched the reference lists of included studies, unpublished 'grey' literature and conference proceedings and contacted pharmaceutical companies for details of unpublished trials. We included randomised and quasi-randomised controlled trials that compared patching the eye with no patching to treat simple corneal abrasions. Two authors independently assessed the risk of bias and extracted data. Investigators were contacted for further information regarding the quality of trials. The primary outcome was healing at 24, 48 and 72 hours while secondary outcomes included measures of pain, quality of life and adverse effects. We graded the certainty of the evidence using GRADE. We included 12 trials which

  17. Rubberized Concrete Durability Against Abrasion

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    Md Noor Nurazuwa

    2016-01-01

    Full Text Available Durability performance of rubberized concrete against abrasion is presented in this paper. Surface depth loss was measured when abrasion load was constantly applied on concrete surface at each 500 interval rotation. Specimen with water-to cement ratio of 0.50 and 0.35 was prepared and tested at 28 days of curing age. In addition, 10% silica fume, SF was added to provide denser concrete and to understand its effectiveness against wear when added with crumb rubber. Results showed that crumb rubber shows good potential in providing abrasion resistance to concrete mix. However, in the case of rubberized concrete with silica fume, abrasion resistance was found to be slightly decreased with compressive strength more than 50N/mm2 due to the lack of low elastic modulus of CR particles to accommodate with denser cement matrix.

  18. 30 CFR 72.610 - Abrasive blasting.

    Science.gov (United States)

    2010-07-01

    ... 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 underground mines. When an abrasive blasting operation is performed, all exposed miners shall properly...

  19. 30 CFR 58.610 - Abrasive blasting.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Abrasive blasting. 58.610 Section 58.610... SAFETY AND HEALTH HEALTH STANDARDS FOR METAL AND NONMETAL MINES Miscellaneous § 58.610 Abrasive blasting. (a) Surface and underground mines. When an abrasive blasting operation is performed, all...

  20. Lichen Planus-a Clinico-histopathological

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    Garg Vijay

    2000-01-01

    Full Text Available 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 cases. Mucosal involvement was seen in 24% in addition to skin involvement ; nail involvement hypertrophicus (17.3%. Lichen planopilaris and oral lichen planus were uncommon. Clinico-histopathological discrepancies were observed in 7 patients. Civatte bodies were seen in only 37% of cases.

  1. New concepts in air abrasion.

    Science.gov (United States)

    Porth, R N

    1998-03-01

    There is no doubt that air abrasion is going to be part of the millennial shift in dentistry away from traditional treatment modalities. With the change in incidence and morphology of caries as a result of the hardening effect of fluoride on enamel, this ability to remove only decayed areas and permanently seal the less susceptible areas becomes increasingly desirable.

  2. Visualisation of Abrasive Particles in Suction Part of Abrasive Cutting Head

    OpenAIRE

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

    2013-01-01

    The development of numerical model of processes occurring in the abrasive water jet cutting head during the process of creation and forming of abrasive water jet is currently in the progress at the Institute of Geonics in Ostrava. Verification of the model requires among others to determine behaviour of abrasive particles at the input of the cutting head. Therefore, visualisation of abrasive particles at the input using various parameters of abrasive jet and subsequent analysis was...

  3. Air flow exploration of abrasive feed tube

    Science.gov (United States)

    Zhang, Shijin; Li, Xiaohong; Gu, Yilei

    2009-12-01

    An abrasive water-jet cutting process is one in which water pressure is raised to a very high pressure and forced through a very small orifice to form a very thin high speed jet beam. This thin jet beam is then directed through a chamber and then fed into a secondary nozzle, or mixing tube. During this process, a vacuum is generated in the chamber, and garnet abrasives and air are pulled into the chamber, through an abrasive feed tube, and mixes with this high speed stream of water. Because of the restrictions introduced by the abrasive feed tube geometry, a vacuum gradient is generated along the tube. Although this phenomenon has been recognized and utilized as a way to monitor nozzle condition and abrasive flowing conditions, yet, until now, conditions inside the abrasive feed line have not been completely understood. A possible reason is that conditions inside the abrasive feed line are complicated. Not only compressible flow but also multi-phase, multi-component flow has been involved in inside of abrasive feed tube. This paper explored various aspects of the vacuum creation process in both the mixing chamber and the abrasive feed tube. Based on an experimental exploration, an analytical framework is presented to allow theoretical calculations of vacuum conditions in the abrasive feed tube.

  4. Clinico- Pathological Study Of Ichthyosis Vulgaris

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    Nandy Utpal

    1997-01-01

    Full Text Available A clinico- pathological study of 28 cases of ichthyosis vulgaris appeared with in the age of 5 years. The presence of the disease since birth was also found. While most (24 patients showed a diminution of severity in summer with an aggravation during winter, 4 patients followed the opposite seasonal pattern. Only in 4 patients, fine scales in the scalp were detected. One patient showed an affection of flexures. There was also a low occurrence of palmo- planter hyperkeratosis, follicular keratosis, fissuring of hands and feet and atopy.

  5. Recent Developments in Abrasive Hybrid Manufacturing Processes

    Directory of Open Access Journals (Sweden)

    Ruszaj Adam

    2017-06-01

    Full Text Available Recent dynamic development of abrasive hybrid manufacturing processes results from application of a new difficult for machining materials and improvement of technological indicators of manufacturing processes already applied in practice. This tendency also occurs in abrasive machining processes which are often supported by ultrasonic vibrations, electrochemical dissolution or by electrical discharges. In the paper we present the review of new results of investigations and new practical applications of Abrasive Electrodischarge (AEDM and Electrochemical (AECM Machining.

  6. Progress in abrasive and grinding technology

    CERN Document Server

    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

  7. Refractory, Abrasive and Other Industrial Mineral Operations

    Data.gov (United States)

    Department of Homeland Security — This map layer includes refractory, abrasive, and other industrial minerals operations in the United States. The data represent commodities covered by the Minerals...

  8. Clasp retention and composites: an abrasion study.

    Science.gov (United States)

    Davenport, J C; Hawamdeh, K; Harrington, E; Wilson, H J

    1990-08-01

    An in vitro test for screening the abrasion resistance and abrasivity of composite resins when used to provide tooth undercuts for removable partial denture clasps is described. In the present study nine composite resins were tested against wrought stainless steel round clasps. The results indicated that the abrasion of any of the composites tested was unlikely to cause a noticeable loss of retention in the clinical situation. However, there was marked abrasion of the clasps by two of the composites which would be likely to be clinically relevant.

  9. A Study of the Pickup of Abrasive Particles during Abrasion of Annealed Aluminum on Silicon Carbide Abrasive Papers,

    Science.gov (United States)

    annealed aluminium during abrasion on silicon carbide abrasive papers. Neither optical nor scanning electron microscopy adequately characterises the...despite its limitations when examining rough surfaces. The present results show that the pickup of silicon carbide particles increases with increase in

  10. 21 CFR 872.6010 - Abrasive device and accessories.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6010 Abrasive device and accessories... disk, guard for an abrasive disk, abrasive point, polishing agent strip, and polishing wheel....

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

    Directory of Open Access Journals (Sweden)

    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.

  12. Estudio clinico y molecular del sindrome de Noonan

    National Research Council Canada - National Science Library

    Cammarata-Scalisi, Francisco; Neri, Giovanni; Pomponi, Maria Grazia; Mancano, Giorgia; Da Silva, Gloria; Avendano, Andrea; Lacruz-Rengel, Maria Angelina; Stock, Frances; Sosa, Angel

    2012-01-01

    .... Se reporta el caso de un lactante mayor masculino, de 18 meses de edad, evaluado de forma multidisciplinaria con diagnostico clinico y molecular de sindrome de Noonan, con la mutacion en sentido...

  13. [Clinico-roentgenological semiotics of the chest damage in polytrauma].

    Science.gov (United States)

    Zamiatin, P N; Panchenko, E V; Grigor'ian, G O; Goloshchapova, E V

    2006-10-01

    There are presented the main clinico-roentgenological signs of the chest damage in the injured persons, suffering polytrauma, according to the data from the specialized department of traumatic shock and polytrauma.

  14. Dermopathy of Graves' disease: Clinico-pathological correlation.

    Science.gov (United States)

    Reddy, Sagili Vijaya Bhaskar; Gupta, Sushil Kumar; Jain, Manoj

    2012-05-01

    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.

  15. Restorative resins: abrasion vs. mechanical properties.

    Science.gov (United States)

    Jørgensen, K D

    1980-12-01

    The purpose of the present work was to examine whether it is possible by simple and reliable laboratory tests to evaluate the abrasion by food of Class 1 restorative resins. The results point to the following main conclusions: for the smooth-surface resins, i.e. the micro-filled composite and the unfilled resins, the Wallace hardness test appears to be a valid parameter for abrasion; the greater the depth of penetration of the Vickers diamond of this apparatus, the more severe abrasion is to be expected. The mode of abrasion in this type of resin is scratching. Porosity in the resins strongly enhances the abrasion. For the rough-surface resins, i.e. the conventional composites, a dual effect of the filler particles was concluded. The filler particles on the one hand protect the matrix against abrasion, but cause, on the other hand, in time an increase of the surface roughness of the composite and thereby via increased friction an increase of the abrasion. Considerations on possible ways to improve the present-day restorative resins are presented. It is stressed that the results obtained refer only to abrasion of Class 1 fillings by food.

  16. Inappropriatezza prescrittiva delle colonscopie: un audit clinico

    Directory of Open Access Journals (Sweden)

    Matteo Marcosignori

    2012-12-01

    Full Text Available Background. La colonscopia è una tecnologia diagnostico-terapeutica ad ampia diffusione, ma ad elevato rischio di inappropriatezza. Infatti, la letteratura ha più volte ribadito la necessità di strategie per verificarne l’appropriatezza prescrittiva, suggerendo gli strumenti necessari per raggiungere questo obiettivo. Nella zona di Ancona si è assistito negli ultimi anni ad un continuo incremento del numero di richieste di colonscopie con conseguente allungamento delle liste di attesa e aumento della spesa. Obiettivi. Pianificare e condurre un audit clinico finalizzato a misurare l’appropriatezza prescrittiva delle colonscopie nella zona di Ancona, identificando le più frequenti indicazioni inappropriate e le principali categorie di prescrittori inappropriati. Metodi. Studio osservazionale prospettico che ha incluso pazienti sottoposti a colonscopia dal 1 novembre 2008 al 28 febbraio 2009, in tre unità operative di endoscopia digestiva nella zona di Ancona. L’appropriatezza delle prestazioni è stata valutata dal confronto con gli standard assistenziali definiti dall’American Society for Gastrointestinal Endoscopy, adattati al contesto locale da un gruppo di lavoro multiprofessionale. Risultati. Su 1.082 colonscopie analizzate, il tasso di appropriatezza è risultato del 58,4%. Le principali indicazioni inappropriate rilevate sono “sorveglianza dopo rimozione di polipi non cancerizzati”, “screening del cancro del colon-retto”, “dolore addominale acuto”, “stipsi cronica”. Tra i principali prescrittori inappropriati i gastroenterologi, i medici di medicina generale (MMG e i chirurghi. Gli esami con indicazioni appropriate hanno dimostrato maggiore probabilità di portare a riscontri endoscopici significativi, in particolare a lesioni cancerose. Un numero limitato di neoplasie maligne è stato individuato anche nel corso di colonscopie inappropriate. Limiti. Le tre UU.OO. coinvolte non hanno contributo all

  17. Life cycle and sustainability of abrasive tools

    CERN Document Server

    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.

  18. The abrasion and impact-abrasion behavior of austempered ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Dogan, Omer N.; Lerner, Y.S. (University of Northern Iowa)

    1998-01-01

    Austempering of ductile irons has led to a new class of irons, Austempered Ductile Irons (ADIs), with improved mechanical strength and fracture toughness lacking in gray cast irons. Laboratory wear tests have been used to evaluate the abrasive and impact-abrasive wear behavior of a suite of ADIs. The use of high-stress, two-body abrasion, low-stress, three-body abrasion, and impact-abrasion tests provides a clear picture of the abrasive wear behavior of the ADIs and the mechanisms of material removal. When combined with hardness measurements, fracture toughness and a knowledge of the microstructure of the ADIs, the overall performance can be assessed relative to more wear resistant materials such as martensitic steels and high-chromium white cast irons

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Science.gov (United States)

    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.

  1. Third abrasive wear mode: is it possible?

    Directory of Open Access Journals (Sweden)

    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”.

  2. Clinico-histologic conferences: histology and disease.

    Science.gov (United States)

    Shaw, Phyllis A; Friedman, Erica S

    2012-01-01

    Providing a context for learning information and requiring learners to teach specific content has been demonstrated to enhance knowledge retention. To enhance students' appreciation of the role of science and specifically histology in clinical reasoning, disease diagnosis, and treatment, a new teaching format was created to provide clinical context, promote integration and application of science knowledge, and to foster peer teaching and learning: the Clinico-Histologic Conference (CHC) for the Mount Sinai School of Medicine Histology course. Teams of six students were each assigned specific disease processes and were charged with creating oral presentations and handouts that taught their classmates about the clinical manifestations, etiopathogeneses, diagnoses, and treatments of the assigned processes, along with comparisons of normal histology to the pathology of the disease. Each team also created four questions, some of which were used on Histology written examinations. The physician facilitator evaluated the presentation and handouts. About two-thirds of students agreed the CHC enhanced appreciation of the importance of histology, provided a context for integration and application of basic science to patient care and enhanced their ability to teach their peers. Student feedback demonstrated that the CHCs were successful in promoting teamwork, peer teaching, and the application of histology to diagnose diseases. The authors believe that teaching basic science content in this new format enhanced student learning and application of medical knowledge, and that this new teaching format can be adopted by other medical school courses.

  3. Verrucous hyperplasia: A clinico-pathological study.

    Science.gov (United States)

    Hazarey, Vinay K; Ganvir, Sindhu M; Bodhade, Ashish S

    2011-05-01

    Oral verrucous hyperplasia (OVH) is a premalignant lesion that may transform into an oral cancer. The present retrospective study was carried out to analyze the clinico-pathological features of verrucous hyperplasia (VH). Total 19 diagnosed cases of verrucous hyperplasia were retrospectively analyzed for demographic, clinical and histopathological features including dysplasia. Average age of occurrence of lesion was 4 (th) decade of life, with male predominance (2:1) and common site of occurrence being buccal mucosa. Clinically it present as verrucous exophytic growth with sharp or blunt projections on surface, which corresponds histologically. Tobacco lime quid placement in buccal vestibule was key etiologic factor. Histopathologicaly 68% cases showed dysplasia out of which moderate dysplasia predominates (42%). Moderately dysplastic cases were found to be associated with mixed habit pattern. Maximum cases were treated with excision. Biopsy specimen comprising of adjacent normal epithelium is key in distinguishing verrucous hyperplasia from verrucous carcinoma. Clinical behavior and recurrence potential needs to be assessed with long term follow up studies.

  4. Evaluation of Rheological Properties of Gel Abrasive in Magnetic Abrasive Finishing

    Directory of Open Access Journals (Sweden)

    A-Cheng Wang

    2013-01-01

    Full Text Available The purpose of this study was aimed at the evaluation of the mechanism of magnetic finishing with gel abrasive (MFGA, during which the performance of MFGA was compared to that of magnetic abrasive finishing (MAF. Of importance is that MFGA performs better than MAF based on the polishing-efficiency criterion. Silicone gels, however, are semisolid polymer gels with deforming properties that are temperature dependent, ultimately influencing significantly the polishing efficiency in MFGA. Therefore, taking as examples cylindrical rods which were polished using silicone gels with different plasticities to determine the corresponding temperatures of abrasive media in the working area, this study evaluated the MFGA mechanism to elucidate the properties of silicone gels and attain both the finished effect and effective gel abrasives in MFGA to produce a highly efficient polished surface. Next, circulating effects of abrasive media were identified to ensure the efficiency in MFGA and establish the relation between the concentrations of abrasive media and circulating effects in the working area. Experimental results show that silicone gels with low plasticity produce high temperature of abrasive media in MFGA; high temperature of abrasive medium makes excellent circulating effects in the working area, inducing high material removal and fine surface roughness.

  5. Investigations on the trajectories of magnetic abrasive grains in magnetic induction-free abrasive wire sawing

    Science.gov (United States)

    Zhang, Wei; Yao, Chunyan; Tang, Chen; Qiu, Tengwei; Xu, Xuefeng

    2016-12-01

    This study presents a novel method of magnetic induction-free abrasive wire sawing. The ferromagnetic wire is magnetized in a uniform magnetic field, forming a high-gradient magnetic field that separates into paramagnetic and diamagnetic regions. Paramagnetic abrasive grains are attracted to the paramagnetic region and adhere to the wire surface but are repelled from the diamagnetic region. The trajectory of the magnetic abrasive grains is analyzed in a mathematical model and in COMSOL Multiphysics simulations. The results are verified by test investigations on the motions and adsorption of the magnetic abrasive grains using a dynamic microscope system. The detailed grain trajectories are investigated in a numerical model. Because it actively transports grains toward the wire (where they can be transported to the sawing channel), our proposed method achieves more efficient wire sawing performance than traditional free abrasive wire sawing. Such efficient performance is highly sought in silicon wafering technologies, which are commonly used in the solar and semiconductor industries.

  6. Cutaneous vasculitides: Clinico-pathological correlation

    Directory of Open Access Journals (Sweden)

    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

  7. 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

    Directory of Open Access Journals (Sweden)

    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.

  8. Basics of cutting and abrasive processes

    CERN Document Server

    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.

  9. Clinico-radiological spectrum of reversible splenial lesions in children.

    Science.gov (United States)

    Kashiwagi, Mitsuru; Tanabe, Takuya; Shimakawa, Shuichi; Nakamura, Michiko; Murata, Shinya; Shabana, Kousuke; Shinohara, Jun; Odanaka, Yutaka; Matsumura, Hideki; Maki, Koh; Okumura, Kenichi; Okasora, Keisuke; Tamai, Hiroshi

    2014-04-01

    Recently, many cases of children presenting reversible splenial lesions during febrile illness (RESLEF) have been reported; however, their overall clinico-radiological features are unclear. To describe the clinico-radiological features, we retrospectively reviewed the etiology (pathogen), clinical course, laboratory data, magnetic resonance imaging and electroencephalography (EEG) findings, therapy, and prognosis of 23 episodes in 22 children (1 child recurred) who presented neurological symptoms, with RESLEF. The etiologies (pathogens) varied. Seizure occurred in 7 episodes, disturbance of consciousness (DC) in 13, and delirious behavior in 18. Serum sodium levels cases. Slow waves were observed on EEG in 10 episodes. Methylprednisolone pulse therapy was given in 7 cases. No case resulted in neurological sequelae. Among 23 episodes, clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) was diagnosed in 6 episodes, whereas non-MERS was observed in 17 episodes. No difference was observed in almost all the clinico-radiological features' data between the 2 groups. The largest differences were observed in the rate of purposeless movement, DC, extension of the abnormal lesions outside the splenium, and marked slowing of background activity on EEG. RESLEF exhibit a spectrum of clinico-radiological features. These results suggest that non-MERS and MERS both are a part of a larger pathological condition, which we have termed as RESLEF spectrum syndrome. Given the view that such a syndrome exists, the clinical characteristics and position of non-MERS and MERS become clear.

  10. Project Clinico. Final Evaluation Report, 1992-93. OREA Report.

    Science.gov (United States)

    New York City Board of Education, Brooklyn, NY. Office of Research, Evaluation, and Assessment.

    Project Clinico, a federally-funded bilingual education project, served 356 special education students of limited English proficiency in its second year of operation at six elementary schools in New York City (New York). The project provided special and modified instructional services for these students, consultation and training to teachers,…

  11. Abrasion test of flexible protective materials on hydraulic structures

    Directory of Open Access Journals (Sweden)

    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.

  12. The application of air abrasion in dentistry

    Directory of Open Access Journals (Sweden)

    Mandinić Zoran

    2014-01-01

    Full Text Available One of the main objectives of contemporary dentistry is to preserve healthy tooth structure by applying techniques of noninvasive treatment. Air abrasion is a minimally invasive nonmechanical technique of tooth preparation that uses kinetic energy to remove carious tooth structure. A powerful narrow stream of moving aluminum-oxide particles hit the tooth surface and they abrade it without heat, vibration or noise. Variables that affect speed of cutting include air pressure, particle size, powder flow, tip’s size, angle and distance from the tooth. It has been proposed that air abrasion can be used to diagnose early occlusal-surface lesions and treat them with minimal tooth preparation using magnifier. Reported advantages of air abrasion include reduced noise, vibration and sensitivity. Air abrasion cavity preparations have more rounded internal contours than those prepared with straight burs. This may increase the longevity of placed restorations because it reduces the incidence of fractures and a consequence of decreased internal stresses. However, air abrasion cannot be used for all patients, i.e. in cases involving severe dust allergy, asthma, chronic obstructive lung disease, recent extraction or other oral surgery, open wounds, advanced periodontal disease, recent placement of orthodontic appliances and oral abrasions, or subgingival caries removal. Many of these conditions increase the risk of air embolism in the oral soft tissues. Dust control is a challenge, and it necessitates the use of rubber dam, high-volume evacuation, protective masks and safety eyewear for both the patient and the therapist. [Projekat Ministarstva nauke Republike Srbije, br. 46009

  13. Estudo epidemiológico e avaliação de fatores de risco da infecção por Toxoplasma gondii e achados clinico-patológicos da infecção aguda em cães admitidos em um Hospital Escola Veterinário

    Directory of Open Access Journals (Sweden)

    Angelita D. Strital

    Full Text Available RESUMO: Esse trabalho teve como objetivo estudar a prevalência e respectivos fatores de risco para infecção do Toxoplasma gondii em cães provenientes de uma população hospitalar. Além disso, avaliou-se as taxas de ocorrência e as repercussões clínico-patológicas da infecção aguda pelo T. gondii nesses animais. Anticorpos foram detectados em 7% (26/386 da população estudada, composta de 386 cães de ambos os sexos e diferentes raças e idades. Somente as variáveis, ingestão de vísceras, origem rural e contato com bovinos apresentaram valores significativos com p<0.05. Adicionalmente os cães de origem rural apresentaram maiores risco (OD=7.00 de infecção do que aqueles de origem urbana. Em 6,5% (25/386 foram detectados títulos de contato (entre 16 e 256; esses títulos não significam necessariamente infecção aguda e sim apenas exposição prévia. É de fundamental importância o reconhecimento da infecção prévia por T. gondii nesses pacientes hospitalares. Dependendo da causa da admissão, mesmo não sendo a toxoplasmose a responsável, o paciente deve receber o tratamento anti-protozoário profilaticamente ou ser monitorado para posterior tratamento em caso de reagudização da enfermidade por recrudescência dos bradizoítos encistados. Apenas um animal (3.44%, 1/386 foi admitido com titulação elevada, o qual pode ser sugestivo de infecção aguda (titulo de 4096. Embora o animal com infecção aguda tenha sido apresentado com sinais neurológicos, cautela é necessária para não extrapolar uma falsa interpretação que a toxoplasmose é a grande responsável por quadros neurológico, uma vez que inúmeros outros casos incluídos nesse estudo tinham manifestações neurológicas e não tinham títulos de infecção aguda, nem mesmo título de contato prévio. A toxoplasmose aguda não foi uma afecção clínica expressiva nessa ambiência hospitalar, no entanto diagnóstico diferencial deve ser feito nos pacientes

  14. PC controlled toothbrush/dentifrice abrasion machine.

    Science.gov (United States)

    Bal, G; Uçtaşli, S; Bekiroğlu, E

    1999-02-01

    A toothbrush/dentifrice abrasion machine was developed to use in dental research laboratory. The mechanism was designed as a hexagonal block driven by two stepping motors which move the mechanism in four directions. In order to control the stepping motors speed, position and direction commands or signals were generated by a software written in C Programming Language and then these commands were applied the stepping motor drives through parallel port of a personal computer. The toothbrush/dentifrice abrasion machine was finally used to measure different longevity of tooth brush. It was experimentally shown that the mechanism can be used for highly accurate position and speed applications.

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

    Science.gov (United States)

    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.

  16. 21 CFR 872.6030 - Oral cavity abrasive polishing agent.

    Science.gov (United States)

    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...

  17. 9 CFR 311.14 - Abrasions, bruises, abscesses, pus, etc.

    Science.gov (United States)

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Abrasions, bruises, abscesses, pus... PARTS § 311.14 Abrasions, bruises, abscesses, pus, etc. All slight, well-limited abrasions on the tongue... a carcass which is badly bruised or which is affected by an abscess, or a suppurating sore shall...

  18. Opportunities in Abrasive Water Jet Machining

    NARCIS (Netherlands)

    Hoogstrate, A.M.; Karpuschewski, B.; van Luttervelt, C.A.; Meijer, J.; Kals, H.J.J.

    1997-01-01

    In the recent years the interest in loose abrasive machining processes as efficient, flexible processes is rising. This paper describes the development of a ‘coherent set of models’ for a category of these processes, namely those which use high velocity of the particles to obtain the necessary

  19. Performance Enhancement of Abrasive Waterjet Cutting

    NARCIS (Netherlands)

    Vu Ngoc Pi

    2008-01-01

    Abrasive Waterjet (AWJ) Machining is a recent non-traditional machining process. This technology is widely used in industry for cutting difficult-to-machine-materials, milling slots, polishing hard materials etc. AWJ machining has many advantages, e.g. it can cut net-shape parts, no heat is generate

  20. Evaluation and Treatment of Perioperative Corneal Abrasions

    Directory of Open Access Journals (Sweden)

    Kira L. Segal

    2014-01-01

    Full Text Available Purpose. To evaluate perioperative risk factors for corneal abrasion (CA and to determine current care for perioperative CA in a tertiary care setting. Methods. Hospital-based, cross-sectional study. In Operating Room and Post-Anesthesia Care Units patients, a comparison of cases and controls was evaluated to elucidate risk factors, time to treatment, and most common treatments prescribed for corneal abrasions. Results. 86 cases of corneal abrasion and 89 controls were identified from the 78,542 surgical procedures performed over 2 years. Statistically significant risk factors were age (P=0.0037, general anesthesia (P<0.001, greater average estimated blood loss (P<0.001, eyes taped during surgery (P<0.001, prone position (P<0.001, trendelenburg position (P<0.001, and supplemental oxygen en route to and in the Post-Anesthesia Care Units (P<0.001. Average time to complaint was 129 minutes. 94% of cases had an inpatient ophthalmology consult, with an average time to consult of 164 minutes. The most common treatment was artificial tears alone (40%, followed by combination treatment of antibiotic ointment and artificial tears (35.3%. Conclusions. Trendelenburg positioning is a novel risk factor for CA. Diagnosis and treatment of perioperative corneal abrasions by an ophthalmologist typically require three hours in the tertiary care setting.

  1. Performance Enhancement of Abrasive Waterjet Cutting

    NARCIS (Netherlands)

    Vu Ngoc Pi

    2008-01-01

    Abrasive Waterjet (AWJ) Machining is a recent non-traditional machining process. This technology is widely used in industry for cutting difficult-to-machine-materials, milling slots, polishing hard materials etc. AWJ machining has many advantages, e.g. it can cut net-shape parts, no heat is

  2. Concrete ice abrasion rig and wear measurements

    NARCIS (Netherlands)

    Shamsutdinova, G.; Rike, P.B.; Hendriks, M.A.N.; Jacobsen, S.

    2015-01-01

    The wear of concrete material due to ice movement is a challenge for offshore and coastal structures. Concrete surfaces exposed to moving ice are subjected to wear at various rates depending on concrete and ice properties. At NTNU, Department of Structural Engineering, concrete ice abrasion phenomen

  3. Performance Enhancement of Abrasive Waterjet Cutting

    NARCIS (Netherlands)

    Vu Ngoc Pi

    2008-01-01

    Abrasive Waterjet (AWJ) Machining is a recent non-traditional machining process. This technology is widely used in industry for cutting difficult-to-machine-materials, milling slots, polishing hard materials etc. AWJ machining has many advantages, e.g. it can cut net-shape parts, no heat is generate

  4. Concrete ice abrasion rig and wear measurements

    NARCIS (Netherlands)

    Shamsutdinova, G.; Rike, P.B.; Hendriks, M.A.N.; Jacobsen, S.

    2015-01-01

    The wear of concrete material due to ice movement is a challenge for offshore and coastal structures. Concrete surfaces exposed to moving ice are subjected to wear at various rates depending on concrete and ice properties. At NTNU, Department of Structural Engineering, concrete ice abrasion phenomen

  5. Development of an Abrasive Water Jet Optimum Abrasive Flow Rate Model for Titanium Alloy Cutting (Preprint)

    Science.gov (United States)

    2006-05-01

    As the abrasive water jet (AWJ) is used in industry extensively, optimization of the process parameters that determine efficiency, economy and...quality of the process is becoming more and more important for its successful application. However, being a complicated cutting system, an abrasive water ... jet is characterized by a large number of process parameters, which include water pressure, orifice diameter, traverse rate, standoff distance, impact

  6. Usage of abrasion-resistant materials in agriculture

    Directory of Open Access Journals (Sweden)

    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.

  7. Thermal aspects of ice abrasive water jet technology

    Directory of Open Access Journals (Sweden)

    Marko Jerman

    2015-08-01

    Full Text Available During the last few years, different research groups have been developing systems for the transition of abrasive water jet into ice abrasive water jet. The aim of this new technology is to make the technology cleaner from both practical and ecological points of view. Mineral abrasive is replaced with ice grains that melt away after the machining process, leaving the workpiece uncontaminated. Several different approaches to this technology were studied. Thermal aspects of integrating the ice abrasive water jet technology into commercially available machines were considered. The results and analyses of water temperature measurements on the ice abrasive water jet machine are presented in this article.

  8. Properties, structure and machnining capabilities sintered corundum abrasives

    Directory of Open Access Journals (Sweden)

    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.

  9. INTERNAL FINISHING OF CYLINDRICAL PIPES USING SINTERED MAGNETIC ABRASIVES

    Directory of Open Access Journals (Sweden)

    PALWINDER SINGH

    2011-07-01

    Full Text Available An internal magnetic abrasive finishing (MAF process was proposed to produce highly finished inner surfaces of workpieces used in critical applications. The process principle and the finishing characteristics of magnetic abrasive finishing of cylindrical pipes using sintered magnetic abrasives are described in this research work. Thesintered magnetic abrasive is a mixture of Al2O3 abrasive and ferromagnetic particles. The Al2O3 based sintered magnetic abrasives have been developed in sintering machine. The surface roughness measurements resulting from finishing experiments demonstrate the effects of the abrasive behavior on the surface modifications. Thesurface finish was analysed in terms of percent improvement in surface finish (PISF. Also surface finish was analysed using Response Surface Methodology (RSM. The obtained maximum PISF was 95% and minimum surface roughness was 0.05 μm Ra. To further study the improvement in surface finish, the surface was microscopically examined using X-Ray Diffraction (XRD.

  10. The effect of bleaching on toothbrush abrasion of resin composites

    Directory of Open Access Journals (Sweden)

    Hila Hajizadeh

    2013-01-01

    Full Text Available Aim: This experimental study was designed to focus on the effects of bleaching on toothbrush abrasion in three types of composites with different filler size. Materials and Methods: Forty eight disks were prepared from three types of composite and divided into 6 groups. In the first three groups the abrasion test was done. The remaining groups were bleached and the abrasion test was performed. The weight of the samples before and after abrasion was measured. Statistical analysis was done with one-way ANOVA and Duncan test. Results: There was a significant difference in abrasion of composites with different filler size (P < 0.05. The most amount of abrasion was observed in Z100 after being bleached. An increase in abrasion was noticed in all three types of tested composite after bleaching. Conclusion: According to the findings, it is suggested to use a nano filled resin composite for restoration if the bleaching treatment is required.

  11. Calcifying epithelial odontogenic tumor: a clinico-radio-pathological dilemma.

    Science.gov (United States)

    Hada, M S; Sable, M; Kane, S V; Pai, Prathamesh S; Juvekar, S L

    2014-01-01

    The calcifying epithelial odontogenic tumor (CEOT) is a rare benign neoplasm of mandible in adults. The presentation of this entity is varied and often confused with a variety of mucosal and jaw lesions and clinical, radiological, and pathological feature of CEOT often-mimic malignancy. The objective of this report is to highlight the clinical features and radiological findings which should arouse suspicion of a benign lesion and importance of providing adequate clinical information to the pathologist to attain accurate diagnosis.We discussed two cases with tumors located in the maxilla. Both presented as expansile lesions with one biopsy proven squamous cell carcinoma. Both were pursued with clinico-radiological suspicion of benign lesions and confirmed with pathological correlation of histology and immunohistochemistry as CEOT. Therefore a High index of suspicion and clinico-radiological information are the key feature for diagnosis of this rare tumor.

  12. Measurement of nanoparticle removal by abrasion

    Science.gov (United States)

    Guiot, Arnaud; Golanski, Luana; Tardif, François

    2009-05-01

    A strong release limitation of single nanoparticles from commercial manufactured "nanoproducts" is necessary to decrease potential exposure risks of consumers and represents also a pragmatic way to facilitate acceptance for nanomaterial commercialization before obtaining definitive toxicological results. So, it is of prime importance to know how to characterize the release of small materials during usage solicitations such as mechanical, thermal, UV stress: are they single nanoparticles, aggregates or nanoparticles included in a bigger piece of the matrix? In the frame of NanoSafe2 project, CEA developed and qualified a specific bench test where the material to be tested is mechanically solicited by abrasion using a normalized Taber equipment. The first results show that nanofillers can be released in usage by abrasion for non optimised nanoproducts.

  13. Protese testicular de colageno na orquiectomia subcapsular : estudo clinico-experimental

    OpenAIRE

    Paulo Cesar Rodrigues Palma

    1988-01-01

    Resumo: Este trabalho foi realizado no Núcleo de Medicina e Cirurgia Experimental da Faculdade de ciências Médicas e no Hospital das Clínicas da Universidade Estadual de Campinas, com o intuito de introduzir uma nova prótese testicular na orquiectomia subcapsular, como tratamento paliativo do cancer prostatico avançado. A prótese biológica desenvolvida pelo Prof. Dr. Benedicto de Campos Vidal do Departamento de Biologia Celular da universidade Estadual de Campinas foi elaborada com colágeno l...

  14. Uncertainty sources in radiopharmaceuticals clinical studies; Fontes de incertezas em estudos clinicos com radiofarmacos

    Energy Technology Data Exchange (ETDEWEB)

    Degenhardt, Aemilie Louize; Oliveira, Silvia Maria Velasques de, E-mail: silvia@cnen.gov.br, E-mail: amilie@bolsista.ird.gov.br [Instituto de Radioprotecao e Dosimetria, (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2014-07-01

    The radiopharmaceuticals should be approved for consumption by evaluating their quality, safety and efficacy. Clinical studies are designed to verify the pharmacodynamics, pharmacological and clinical effects in humans and are required for assuring safety and efficacy. The Bayesian analysis has been used for clinical studies effectiveness evaluation. This work aims to identify uncertainties associated with the process of production of the radionuclide and radiopharmaceutical labelling as well as the radiopharmaceutical administration and scintigraphy images acquisition and processing. For the development of clinical studies in the country, the metrological chain shall assure the traceability of the surveys performed in all phases. (author)

  15. Abrasion Resistance Comparison between Rotor and Ring Spun Yarn

    Institute of Scientific and Technical Information of China (English)

    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.

  16. Thermal aspects of ice abrasive water jet technology

    OpenAIRE

    Marko Jerman; Henri Orbanić; Mihael Junkar; Andrej Lebar

    2015-01-01

    During the last few years, different research groups have been developing systems for the transition of abrasive water jet into ice abrasive water jet. The aim of this new technology is to make the technology cleaner from both practical and ecological points of view. Mineral abrasive is replaced with ice grains that melt away after the machining process, leaving the workpiece uncontaminated. Several different approaches to this technology were studied. Thermal aspects of integrating the ice a...

  17. Thermal aspects of ice abrasive water jet technology

    OpenAIRE

    Orbanić, Henri; Lebar, Andrej; Junkar, Mihael; Jerman, Marko

    2016-01-01

    During the last few years, different research groups have been developing systems for the transition of abrasive water jet into ice abrasive water jet. The aim of this new technology is to make the technology cleaner from both practical and ecological points of view. Mineral abrasive is replaced with ice grains that melt away after the machining process, leaving the workpiece uncontaminated. Several different approaches to this technology were studied. Thermal aspects of integrating the ice a...

  18. A new dimension to conservative dentistry: Air abrasion

    Directory of Open Access Journals (Sweden)

    Hegde Vivek

    2010-01-01

    Full Text Available Air abrasion dentistry has evolved over a period of time from a new concept of an alternative means of cavity preparation to an essential means of providing a truly conservative preparation for preservation of a maximal sound tooth structure. The development of bonded restorations in combination with air abrasion dentistry provides a truly minimal intervention dentistry. This article reviews the development of air abrasion, its clinical uses, and the essential accessories required for its use.

  19. A new dimension to conservative dentistry: Air abrasion.

    Science.gov (United States)

    Hegde, Vivek S; Khatavkar, Roheet A

    2010-01-01

    Air abrasion dentistry has evolved over a period of time from a new concept of an alternative means of cavity preparation to an essential means of providing a truly conservative preparation for preservation of a maximal sound tooth structure. The development of bonded restorations in combination with air abrasion dentistry provides a truly minimal intervention dentistry. This article reviews the development of air abrasion, its clinical uses, and the essential accessories required for its use.

  20. Machining human dentin by abrasive water jet drilling.

    Science.gov (United States)

    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.

  1. The Abrasion-resistance Investigation of Rubberized Concrete

    Institute of Scientific and Technical Information of China (English)

    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. Controlled toothbrush abrasion of softened human enamel.

    Science.gov (United States)

    Voronets, J; Jaeggi, T; Buergin, W; Lussi, A

    2008-01-01

    The aim of this in vitro study was to compare toothbrush abrasion of softened enamel after brushing with two (soft and hard) toothbrushes. One hundred and fifty-six human enamel specimens were indented with a Knoop diamond. Salivary pellicle was formed in vitro over a period of 3 h. Erosive lesions were produced by means of 1% citric acid. A force-measuring device allowed a controlled toothbrushing force of 1.5 N. The specimens were brushed either in toothpaste slurry or with toothpaste in artificial saliva for 15 s. Enamel loss was calculated from the change in indentation depth of the same indent before and after abrasion. Mean surface losses (95% CI) were recorded in ten treatment groups: (1) soft toothbrush only [28 (17-39) nm]; (2) hard toothbrush only [25 (16-34) nm]; (3) soft toothbrush in Sensodyne MultiCare slurry [46 (27-65) nm]; (4) hard toothbrush in Sensodyne MultiCare slurry [45 (24-66) nm]; (5) soft toothbrush in Colgate sensation white slurry [71 (55-87) nm]; (6) hard toothbrush in Colgate sensation white slurry [85 (60-110) nm]; (7) soft toothbrush with Sensodyne MultiCare [48 (39-57) nm]; (8) hard toothbrush with Sensodyne MultiCare [40 (29-51) nm]; (9) soft toothbrush with Colgate sensation white [51 (37-65) nm]; (10) hard toothbrush with Colgate sensation white [52 (36-68) nm]. Neither soft nor hard toothbrushes produced significantly different toothbrush abrasion of softened human enamel in this model (p > 0.05). Copyright 2008 S. Karger AG, Basel.

  3. Abrasive water jet: a complementary tool

    Directory of Open Access Journals (Sweden)

    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

    Institute of Scientific and Technical Information of China (English)

    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. [Temperature measurements during abrasive water jet osteotomy].

    Science.gov (United States)

    Schmolke, S; Pude, F; Kirsch, L; Honl, M; Schwieger, K; Krömer, S

    2004-01-01

    Working on bone is a major aspect of orthopaedic surgery. Despite its well-known appreciable thermal effects on the edges of the bone cut, the oscillating bone saw blade the oscillating saw remains the standard instrument both for cutting long bones and creating a bed for an endoprosthesis. The application of abrasive water jets offers the possibility of achieving an extremely precise curved cut in bone with no accompanying thermal effect. The thermographically measured absolute temperature increase at the cut edges seen with the water jet was 13 K maximum. The small process forces permit the application in automated handling systems.

  6. Diamond-Fluoroplastic Composites for Abrasive Tools

    Science.gov (United States)

    Adrianova, O. A.; Kirillin, A. D.; Chersky, I. N.

    2001-07-01

    Composite materials based on polytetrafluoroethylene (PTFE) and natural technical diamond powders from Yakutia diamond deposits are developed. It is shown that the compositions based on PTFE and a technical diamond powder at a content of up to 60 wt.%, due to their good physicomechanical characteristics, low friction coefficient, and good wetting of diamond particles by polymer, make is possible to create abrasive tools for polishing and grinding hard metals and semiprecious and precious stones with high serviceability and operational life combined with a considerable increase in the quality of treated surfaces and operational stability of the tools. It is found that PTFE, being a more elastic and softer matrix than the traditional ones, exhibits a self-sharpening effect of diamond grains upon grinding hard surfaces, when the grains go deep into the elastic matrix, the matrix wears out, and the working part of the tool becomes enriched with the diamond powder. These conclusions are confirmed by electron microscopic investigations. It is shown that the introduction of ultradisperse fillings (up to 2 wt.%) into such compositions allows us to improve the characteristics of abrasive tools considerably, especially for grinding hard semiprecious stones. The physicomechanical and frictional characteristics of the compositions and specific examples of their application in the jewelry industry and in stone working are discussed.

  7. Ultrasonic Abrasion: An Alternative for Cavity Preparation

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    PASCARETTI-GRIZON, Florence; MABILLEAU, Guillaume; CHAPPARD, Daniel

    2013-01-01

    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. PMID:24212995

  9. Soybean seedlings tolerate abrasion from air-propelled grit

    Science.gov (United States)

    New tools for controlling weeds would be useful for soybean production in organic systems. Air-propelled abrasive grit is one such tool that performs well for in-row weed control in corn, but crop safety in soybean is unknown. We examined responses to abrasion by corn-cob grit of soybean seedlings a...

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    OpenAIRE

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

    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.

  12. A Finite Element Approach to Modeling Abrasive Wear Modes

    NARCIS (Netherlands)

    Woldman, M.; Heide, van der E.; Tinga, T.; Masen, M.A.

    2016-01-01

    Machine components operating in sandy environments will wear because of the abrasive interaction with sand particles. In this work, a method is derived to predict the amount of wear caused by such abrasive action, in order to improve the maintenance concept of the components. A finite element model

  13. Measurement of the abrasion of radioactive teeth by dentifrices

    Energy Technology Data Exchange (ETDEWEB)

    Hiyoshi, Katsunori; Murai, Syouji (Industrial Research Inst. of Kanagawa Prefecture, Yokohama (Japan)); Hayashi, Ken; Hirai, Taichirou

    1990-05-01

    The purpose of this study is to assess the dentifrice abrasivity of both commercially available products and test products. The assessment of abrasivity was carried out by the measurement of {sup 32}P released from tooth by using radioactive dentifrice abrasion (RDA) method. In dentine, RDA values, which show in polishing ability for dentine, were 65-100 with dentifrices with normal cleaning power and 106-182 with those with high cleaning power, respectively. On the other hand, REA values which slow the polishing ability for enamel were 12-405 with both market products and test products. The difference of the REA values according to the dentrifrices appears to be largely influenced by the difference of polishing agents of each dentifrice. It is concluded that RDA method is useful for assessing of dentifrice abrasivity. However, particular attention should be given to the abrasion of dentine. (author).

  14. Abrasive wear behaviour of as cast and austempered ductile irons

    Energy Technology Data Exchange (ETDEWEB)

    Baydogan, M.; Koekden, M.U.; Cimenoglu, H. [Istanbul Technical Univ., Dept. of Metallurgy and Materials Science Engineering Istanbul (Turkey)

    2000-07-01

    In this study, abrasive wear behaviour of as cast and austempered GGG 50 and GGG 80 quality ductile irons was investigated. In the as cast condition, GGG 50 and GGG 80 quality ductile irons were having ferritic and pearlitic matrix structures, respectively. Austempering at 250 C after austenitisation at 900 C for 100 minutes produced bainitic matrix structure in both of the investigated ductile irons. Abrasive wear tests performed by rubbing the as cast and austempered specimens on Al{sub 2}O{sub 3} abrasive bands, revealed that austempering treatment improves abrasion resistance about 10-70% depending on the abrasive particle size and composition of the base iron. In the as cast condition, pearlitic GGG 80 grade ductile iron, has higher wear resistance than ferritic GGG 50 grade ductile iron. In the austempered condition GGG 50 and GGG 80 grade ductile irons which have bainitic matrix structure, exhibit almost similar wear resistance. (orig.)

  15. Research and development of blasting abrasive made of steelmaking slag

    Institute of Scientific and Technical Information of China (English)

    TANG Oujing

    2015-01-01

    This study focuses on the development of a new type of nonmetallic steelmaking slag abrasive.The performance,processing,and application of steelmaking slag as a nonmetallic abrasive are introduced.The chemical composition,hardness,crushing value,and particle gradation of steelmaking slag are analyzed.A processing method for steelmaking slag as a blasting abrasive is suggested and evaluated.Compared with conventional abrasives such as copper ore sand and cast iron shot,processed steelmaking slag exhibits similar performance and can satisfy abrasive technical requirements.The derusting effect provided by steelmaking slag for a ship deck can reach the Sa2.0 level,and its recyclability is higher than that of copper ore sand.The derusting performance of steelmaking slag is similar to that of copper ore,and it can thus be used in repairing ship decks.

  16. Hydro-abrasive erosion: Problems and solutions

    Science.gov (United States)

    Winkler, K.

    2014-03-01

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

    Science.gov (United States)

    Wiegand, Annette; Schwerzmann, Martina; Sener, Beatrice; Magalhaes, Ana Carolina; Roos, Malgorzata; Ziebolz, Dirk; Imfeld, Thomas; Attin, Thomas

    2008-08-01

    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. 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, or 0.25 mm). A paste-free control slurry (relative enamel abrasion (REA) value 2) and toothpaste slurries with different abrasivity (REA values 6 or 9) were used for brushing. Erosion and abrasion were followed by storing the enamel samples in artificial saliva for 3 h. After each 4th cycle, the samples were stored in artificial saliva for 15 h. After 60 cycles, enamel loss was measured by profilometry and statistically analyzed by two-way and one-way ANOVA and Bonferroni/Dunn post-hoc tests. Loss of enamel (mean, microm) was influenced mainly by the abrasivity of the slurry and increased along with REA value (REA 2: 0.0-0.2, REA 6: 2.1-3.3, REA 9: 2.9-3.7). Abrasion of eroded enamel was also affected by filament stiffness of the toothbrush, but only groups brushed with toothpaste slurry of REA 6 showed any significant difference between the different toothbrushes. Thereby, toothbrushes with 0.2 mm filament diameter caused higher enamel loss than 0.15 and 0.25 mm filaments. Toothbrush abrasion of eroded enamel is influenced mainly by the abrasivity of the toothpaste slurry, but is also modified by toothbrush filament stiffness.

  18. Carga inmediata sobre implante unico: estudio clinico prospectivo.(ARTICULOS ORIGINALES DERIVADOS DE INVESTIGACION)

    National Research Council Canada - National Science Library

    Arango B., Paola Andrea; Arismendi E., Jorge Alberto; Porras, Andres Felipe

    2009-01-01

    ... y disminucion del tiempo total de tratamiento. Se hizo un estudio prospectivo controlado para la colocacion de implantes en casos clinicos de restauracion de diente unico que recogiese el consenso propuesto en la literatura para evaluar el exito...

  19. Valoracion de parametros clinicos y lesiones en organos de cerdos durante el periodo posdestete

    National Research Council Canada - National Science Library

    Mejia-Medina, Julian; Rincon-Ruiz, Juan; Gutierrez-Vergara, Cristian; Correa-Londono, Guillermo; Lopez-Herrera, Albeiro; Parra-Suescun, Jaime

    2012-01-01

    .... En el Centro de Investigacion San Pablo de la Universidad Nacional de Colombia sede Medellin, se evaluaron los parametros clinicos y las lesiones en organos internos en dieciseis cerdos destetados...

  20. [Clinico-psychopathological characteristics of a group of mental patients identified at the internal medicine clinic].

    Science.gov (United States)

    Ostroglazov, V G; Lisina, M A

    1990-01-01

    The authors provide the clinico-psychopathological characteristics of mental patients revealed for the first time during a clinico-epidemiological study of the district therapeutic population. The predominance among them of the somatic psychopathological syndromes was established. The overwhelming majority of those conditions were found to belong to multifactorial mental diseases in whose etiology and pathogenesis the key role is played by interaction between exogenous (psychogenous) and endogenous (thymopathic) factors.

  1. Clinico-mycological study of tinea capitis in Pondicherry

    Directory of Open Access Journals (Sweden)

    Reddy BSN

    1991-01-01

    Full Text Available A clinico-mycological analysis of 68 consecutive clinically diagnosed tinea capitis patients confirmed that the disease affects more commonly prepubertal children of either sex. Salient clinical features in order of frequency included patchy hair loss, scaly patches, black dots and inflammatory lesions with erythema, vesiculation and boggy swelling. Scaly type (36.9% was the most commonly encountered clinical pattern followed by black dot (33.8% and kerion (29.3%. Direct microscopic examination of the affected hair with 20% KOH revealed evidence of fungus in all patients with endothrix (58.8% being the common pattern noted. The rate of culture positivity of the aetiologic fungus grown on Sabouraud′s dextrose agar medium was 82.3%. T. violaceum (66.2% was the most frequently isolated fungus accounting for both inflammatory as well as non-inflammatory lesions.

  2. Cutaneous syncytial myoepithelioma:: Clinico-pathological features and differential diagnosis.

    Science.gov (United States)

    Pizzi, Marco; Facchin, Federico; Kohlscheen, Eva; Sartore, Leonardo; Salmaso, Roberto; Bassetto, Franco

    2016-10-01

    Cutaneous syncytial myoepithelioma (CSM) is a very rare tumor belonging to the spectrum of skin myoepithelial lesions. CSM usually affects the upper extremities of young to middle aged patients and is characterized by peculiar morphological and immunohistochemical features. Unlike classic myoepithelioma, CSM is composed by a densely packed proliferation of spindled to histiocytoid cells, which are variably positive for EMA, S100, SMA, and frequently negative for cytokeratins and GFAP. The peculiar histopathology and the extreme rarity of such lesion (less than 40 cases reported in the literature) can make the diagnosis of CSM a true challenge. In the present case, we report the clinico-pathological features of a primary CSM occurring in a 38 year-old Caucasian man. The differential diagnoses of such lesion are also briefly discussed.

  3. Clinico-pathological study of 30 unicystic ameloblastomas.

    Science.gov (United States)

    Roos, R E; Raubenheimer, E J; van Heerden, W F

    1994-11-01

    The clinico-pathological records of 30 unicystic ameloblastomas collected over a period of 10 years were studied. The mean age at diagnosis was 18.0 years (SD +/- 8.1), most lesions were located in the mandible and were frequently associated with impacted teeth, root resorption and tooth displacement. The unicystic ameloblastomas in 11 patients (4 females and 7 males) exhibited invasion of the fibrous wall, 4 cases (1 female and 3 males) showed intra-luminal proliferation and the remaining 15 specimens (9 females and 6 males) were lined by non-proliferating ameloblastic epithelium. Two cases recurred 3 and 7 years after initial surgical removal. This study reveals the potential aggressive behaviour of unicystic ameloblastomas and underlines the importance of a thorough microscopic examination for sub-classification.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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

  8. [Dependence of the dentinal abrasion of human teeth on their microhardness].

    Science.gov (United States)

    Remizov, S M; Pruzhanskiĭ, L Iu

    1989-01-01

    The dentin resistance against abrasion was studied as related to its microhardness. Sections of 15 intact teeth were investigated (central upper incisors). Water suspensions (40% weight-to weight) of dicalcium phosphate (DCP, FRG; and DKF-1 and DKF-2, USSR) were used as abrasives. Dentin microhardness was measured with a PMT-3 device, and abrasion assessed with profilographic technique. Dentin abrasion was related to its microhardness and to the kind of abrasive used. Dentin abrasion increased as its microhardness decreased. DCF showed minimal abrasive effect, DKF-2 had maximal effect with DKF-1 keeping the intermediate position.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Data.gov (United States)

    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...

  11. Anti-abrasive nanocoatings current and future applications

    CERN Document Server

    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

  12. A review of micro-scale abrasion testing

    Energy Technology Data Exchange (ETDEWEB)

    Gant, A J; Gee, M G [Electronics and Modelling Group, Division of Industry and Innovation, Module 9, Space G9-A5, Queens Road, Teddington, Middlesex, TW11 0LW (United Kingdom)

    2011-02-23

    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

    Science.gov (United States)

    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. Primary duodenal neoplasms: A retrospective clinico-pathological analysis

    Science.gov (United States)

    Bal, Amanjit; Joshi, Kusum; Vaiphei, Kim; Wig, JD

    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. PMID:17373748

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

    Institute of Scientific and Technical Information of China (English)

    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.

  16. Pericoronal radiolucencies with significant pathology: Clinico-histopathologic evaluation

    Directory of Open Access Journals (Sweden)

    Sanjeev Anand

    2015-04-01

    Full Text Available Background: The purpose of the study was to correlate the provisional diagnosis of pericoronal radiolucencies associated with impacted, embedded, or unerupted teeth with the histopathologic diagnosis, and also to emphasize the importance of early detection for better diagnosis and management. Methods: This is a retrospective study involving 18 cases of pericoronal radiolucencies associated with unerupted, embedded, or impacted teeth whose data during 1-year period were retrieved, and were reviewed for clinical, radiological, and histopathologic data. Also, comparison and correlation of clinico-histopathologic diagnosis was made. Results: Of the 18 cases, 11 were provisionally diagnosed as dentigerous cyst and the remaining were diagnosed as ameloblastoma, odontogenic keratocyst, adenomatoid odontogenic tumor, and calcifying epithelial odontogenic cyst. Histopathologic diagnosis of the 18 cases showed varied results, with only 10% correlating with the provisional diagnosis. Conclusion: Although many pathological processes may present radiographically as pericoronal radiolucencies associated with unerupted teeth, the most common is the dentigerous cyst. Hence, it is crucial for the clinician to fully investigate all teeth that fail to erupt at the expected time, and promptly initiate appropriate assessment and management of suspected cystic lesions.

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

    Directory of Open Access Journals (Sweden)

    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.

  18. Infezione da Borrelia burgdorferi: descrizione di un caso clinico atipico

    Directory of Open Access Journals (Sweden)

    Gino Ciarrocchi

    2005-06-01

    Full Text Available La borreliosi o Malattia di Lyme (ML è una malattia infettiva multisistemica causata da una spirocheta, Borrelia burgdorferi, trasmessa dal morso di una zecca del genere Ixodes.Viene descritto il caso clinico di una ragazza di venti anni. In un soggiorno estivo sul Monte Amiata, in Toscana, la giovane notò un arrossamento della pelle al fianco sinistro del corpo. Non osservò presenza della zecca nella zona di presumibile inoculo, da cui si sviluppò un eritema migrante (EM ad andamento centrifugo, fino a raggiungere un diametro di circa 10 centimetri. Nei giorni successivi e durante il follow up non sono mai comparsi sintomi collaterali generali riferibili ad astenia, febbricola, artralgie, malessere, né a carico di organi bersaglio. Dopo circa due settimane, persistendo l’EM, sono stati eseguiti esami sierologici specifici per Borrelia burgdorferi. Al riscontro positivo dei test ELISA e western-blot IgG e IgM, il clnico ha prescritto terapia antibiotica a base di Amoxicillina 2g/die per 20 giorni.Dopo 8-10 giorni di terapia è avvenuta la scomparsa completa dell’eritema. Viene mostrato l’andamento dei test sierologici al momento della diagnosi e durante il follow up, per un periodo di circa cinque mesi.

  19. SINONASAL MASSES: A CLINICO PATHOLOGICAL STUDY AT TERTIARY CARE CENTRE

    Directory of Open Access Journals (Sweden)

    Manish Kumar

    2014-07-01

    Full Text Available AIMS: To study the demography of sinonasal masses, clinical presentation, histopathological pattern and to correlate clinical findings with histopathology. MATERIALS AND METHODS: The present study entitled "Clinico pathological study of sinonasal masses" was carried out in 100 patients who attended the ENT OPD and inpatients in the Department of Otorhinolaryngology and Head and Neck Surgery, Gajra Raja Medical College, Gwalior (M.P. and associated with J.A. Group of Hospitals, Gwalior (M.P. during the period of July 2011 to June 2013 who were diagnosed as cases of sinonasal masses on the basis of clinical and histopathological examination. RESULTS: 32% patients were in age group 15-24 years, 64% were males. Most significant complaints were nasal obstruction and rhinorrhoea. Among 100 patients, nasal polyps were diagnosed in 83 patients, angiofibroma in 7 patients, septal angioma in 2 patients, rhinosporidiosis in 2 patients and one case each of capillary haemangioma, squamous cell carcinoma, angiosarcoma, transitional cell carcinoma and nasopharyngeal carcinoma was present. CONCLUSION: In the present study of masses in sinonasal cavity, most of the patients presented with trivial nasal symptoms, and there is always a possibility to miss the diagnosis if great care is not taken while examining the patient. The findings must be interpreted in light of great clinical suspicion, and complete ENT examination including radiologic and endoscopic studies.

  20. Comminution of Mica by Cavitation Abrasive Water Jet

    Institute of Scientific and Technical Information of China (English)

    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.

  1. Abrasive wear and surface roughness of contemporary dental composite resin.

    Science.gov (United States)

    Han, Jian-min; Zhang, Hongyu; Choe, Hyo-Sun; Lin, Hong; Zheng, Gang; Hong, Guang

    2014-01-01

    The purpose of this study was to evaluate the abrasive wear and surface roughness of 20 currently available commercial dental composite resins, including nanofilled, supra-nanofilled, nanohybrid and microhybrid composite resins. The volume loss, maximum vertical loss, surface roughness (R(a)) and surface morphology [Scanning electron microscopy (SEM)] were determined after wear. The inorganic filler content was determined by thermogravimetric analysis. The result showed that the volume loss and vertical loss varied among the materials. The coefficients of determination (R(2)) of wear volume loss and filler content (wt%) was 0.283. SEM micrographs revealed nanofilled composites displayed a relatively uniform wear surfaces with nanoclusters protrusion, while the performance of nanohybrid composites varied. The abrasive wear resistance of contemporary dental composite resins is material-dependent and cannot be deduced from its category, filler loading and composite matrix; The abrasive wear resistance of some flowable composites is comparable to the universal/posterior composite resins.

  2. Surface Analysis of Metal Materials After Water Jet Abrasive Machining

    Directory of Open Access Journals (Sweden)

    Pavel Polák

    2015-01-01

    Full Text Available In this article, we deal with a progressive production technology using the water jet cutting technology with the addition of abrasives for material removal. This technology is widely used in cutting various shapes, but also for the technology of machining such as turning, milling, drilling and cutting of threads. The aim of this article was to analyse the surface of selected types of metallic materials after abrasive machining, i.e. by assessing the impact of selected machining parameters on the surface roughness of metallic materials.

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

    Directory of Open Access Journals (Sweden)

    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.

  4. Experimental Investigation on the Material Removal of the Ultrasonic Vibration Assisted Abrasive Water Jet Machining Ceramics

    Directory of Open Access Journals (Sweden)

    Tao Wang

    2017-01-01

    Full Text Available The ultrasonic vibration activated in the abrasive water jet nozzle is used to enhance the capability of the abrasive water jet machinery. The experiment devices of the ultrasonic vibration assisted abrasive water jet are established; they are composed of the ultrasonic vibration producing device, the abrasive supplying device, the abrasive water jet nozzle, the water jet intensifier pump, and so on. And the effect of process parameters such as the vibration amplitude, the system working pressure, the stand-off, and the abrasive diameter on the ceramics material removal is studied. The experimental result indicates that the depth and the volume removal are increased when the ultrasonic vibration is added on abrasive water jet. With the increase of vibration amplitude, the depth and the volume of material removal are also increased. The other parameters of the ultrasonic vibration assisted abrasive water jet also have an important role in the improvement of ceramic material erosion efficiency.

  5. Healing effect of Sodium-Sucrose-Octasulfate and EGF on epithelial corneal abrasions in rabbits

    DEFF Research Database (Denmark)

    Johansen, Sven; Heegaard, Steffen; Bjerrum, Kirsten Birgitte;

    1998-01-01

    ophthalmology, Sjögrens syndrome, cornea, abrasion, epidermal growth factor, sodium-sucrose-octasulfate......ophthalmology, Sjögrens syndrome, cornea, abrasion, epidermal growth factor, sodium-sucrose-octasulfate...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Achar, Arun; 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. 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. PMID:21965843

  8. [Clinico-pathological analysis of 45 parotid gland cysts].

    Science.gov (United States)

    Wang, Zhi-ming; Ye, Ming; Yang, Dong-sheng; Ma, Ying; Guan, Qiao-dan

    2016-04-01

    To discuss the clinical and pathological characteristics and management of parotid gland cyst. Forty-five resected samples of parotid gland tumors were selected from Shengjing Hospital of China Medical University from January 2000 to June 2014 whose postoperative pathological diagnosis were parotid gland cysts. The clinico-pathological characteristics in different types of parotid gland cysts were analyzed. Of 45 cases of parotid gland cyst, 25 were males, 20 were females. The median age was 51 years old. 21 cases were located on the left side of parotid gland, while 24 on the right side. The main clinical symptom was painless swelling in parotid gland region. The sizes varied from 0.8 cm×0.6 cm×0.5 cm to 10 cm×2.8 cm×0.6 cm. Nine cases were accompanied with pain, and 36 without. 4 cases were seen with lymph node enlargement, and 41 without pain. The main treatment modality was simple resection of cyst without any injury of facial nerve. No recurrence was seen after following up for 1-10 years. Of the 45 postoperative histopathological results, 29 cases (64.4%) were simple cysts, 9 cases (20.0%) were polycystic disease cysts, and 7 cases (15.6%) were lymphoepithelial cysts. Besides the above-stated pathological manifestations, some non-specific microscopic changes were accompanied with parotid gland cysts, including tumor-like hyperplasia of fibrous tissue, inflammations, calcifications, synovial cyst-like changes, foreign-body giant cell reactions and granulomatous changes. The main symptom of parotid gland cyst is progressive enlargement, and simple resection of cyst is the first-line treatment without facial nerve injury or reoccurrence. The main pathological classifications are simple cysts,lymphoepithelial cysts and polycystic disease cysts.

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

    Science.gov (United States)

    Elhiblu, M. A.; Dua, K.; Mohindroo, J.; Mahajan, S. K.; Sood, N. K.; Dhaliwal, P. S.

    2015-01-01

    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 liver cirrhosis

  10. Clinico-pathological profile of lung cancer in Uttarakhand

    Directory of Open Access Journals (Sweden)

    Rawat Jagdish

    2009-01-01

    Full Text Available Background: Lung cancer is one of the most aggressive and prevalent type of malignancy causing high morbidity and mortality. Tobacco smoking continues to be the leading cause of lung cancer worldwide. An increasing incidence of lung cancer has been observed in India. Objective: The aim of this study was to evaluate the clinico, a pathological profile of the lung cancer in hilly state of Uttrakhand. Materials and Methods: We performed a retrospective analysis of histopathologically proven cases of bronchogenic carcinoma admitted in our hospital from January 1998 to August 2005. Results: Our study included 203 patients with confirmed cases of lung cancer. Male to female ratio was 8.2:1. The common age group being 40-60 years, 9.86% of the patients were less than 40 years old age. Smoking was found to be the main risk factor in 81.77% patients. The most frequent symptom was cough (72.90% followed by fever (58.12%. The most common radiological presentation was mess lesion (46.31%. The most common histopathological type was squamous cell carcinoma (SCC (44.83% followed by adenocarcinoma (19.78% and small cell lung carcinoma (SCLC (16.75%. The majority patients (73.29% were diagnosed in the later stages of the disease (III B and IV. Conclusion: It was found out that SCC was the most frequent histopathological form. SCLC predominates below 40 year and SCC over 60 years of age. Smoking still remains the major risk factors in pathogenesis of lung cancer.

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

    Directory of Open Access Journals (Sweden)

    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

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

    OpenAIRE

    Tsan-Ching CHENG; Cheng, An; Ran HUANG; 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...

  13. Exposure to crystalline silica in abrasive blasting operations where silica and non-silica abrasives are used.

    Science.gov (United States)

    Radnoff, Diane L; Kutz, Michelle K

    2014-01-01

    Exposure to respirable crystalline silica is a hazard common to many industries in Alberta but particularly so in abrasive blasting. Alberta occupational health and safety legislation requires the consideration of silica substitutes when conducting abrasive blasting, where reasonably practicable. In this study, exposure to crystalline silica during abrasive blasting was evaluated when both silica and non-silica products were used. The crystalline silica content of non-silica abrasives was also measured. The facilities evaluated were preparing metal products for the application of coatings, so the substrate should not have had a significant contribution to worker exposure to crystalline silica. The occupational sampling results indicate that two-thirds of the workers assessed were potentially over-exposed to respirable crystalline silica. About one-third of the measurements over the exposure limit were at the work sites using silica substitutes at the time of the assessment. The use of the silica substitute, by itself, did not appear to have a large effect on the mean airborne exposure levels. There are a number of factors that may contribute to over-exposures, including the isolation of the blasting area, housekeeping, and inappropriate use of respiratory protective equipment. However, the non-silica abrasives themselves also contain silica. Bulk analysis results for non-silica abrasives commercially available in Alberta indicate that many contain crystalline silica above the legislated disclosure limit of 0.1% weight of silica per weight of product (w/w) and this information may not be accurately disclosed on the material safety data sheet for the product. The employer may still have to evaluate the potential for exposure to crystalline silica at their work site, even when silica substitutes are used. Limited tests on recycled non-silica abrasive indicated that the silica content had increased. Further study is required to evaluate the impact of product recycling

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

    OpenAIRE

    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...

  15. Abrasive Wear of Four Direct Restorative Materials by Standard and Whitening Dentifrices

    Science.gov (United States)

    2013-06-01

    superficial stains. Insufficient abrasiveness promotes the formation of pellicle and increased bacterial adhesion. Whitening toothpastes generally...production of a pigmented pellicle. Similarly, Saxton (1976) confirmed that an abrasive is necessary to control the thickness of pellicle and to...difficult to remove. However, while insufficient abrasiveness can promote the formation of pellicle and increased bacterial adhesion, excessive

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Exaggerated abrasion/erosion of human dental enamel surfaces

    DEFF Research Database (Denmark)

    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...

  18. Numerical study of agglomerate abrasion in a tumbling mixer

    NARCIS (Netherlands)

    Thanh Nguyen, [No Value; Willemsz, Tofan; Frijlink, Henderik; Maarschalk, Kees van der Voort

    2014-01-01

    A numerical simulation using the Discrete Element Method (DEM) was performed to investigate the phenomena concerning the abrasion and breakage of agglomerates in a diffusion powder mixer. Agglomerates were created by defining a single structure of particles with bonds of different strengths using th

  19. Protective effect of green tea on dentin erosion and abrasion

    Directory of Open Access Journals (Sweden)

    Melissa Thiemi Kato

    2009-12-01

    Full Text Available OBJECTIVE: This in situ study evaluated the protective effect of green tea on dentin erosion (ERO and erosion-abrasion (ABR. MATERIAL AND METHODS: Ten volunteers wore intraoral palatal appliances with bovine dentin specimens subjected to ERO or ERO + toothbrushing abrasion performed immediately (ERO+I-ABR or 30 min after erosion (ERO+30-min-ABR. During 2 experimental 5-day crossover phases, the volunteers rinsed with green tea or water (control, 1 min between each erosive (5 min, cola drink and abrasive challenge (30 s, toothbrushing, 4x/day. Dentin wear was measured by profilometry. RESULTS: The green tea reduced the dentin wear significantly for all conditions compared to control. ERO+I-ABR led to significantly higher wear than ERO, but it was not significantly different from ERO+30-min-ABR. ERO+30-min-ABR provoked significant higher wear than ERO, only for the placebo treatment. CONCLUSIONS: From the results of the present study, it may be concluded that green tea reduces the dentin wear under erosive/abrasive conditions.

  20. Potential of Air-Propelled Abrasives for Selective Weed Control

    Science.gov (United States)

    Novel forms of selective weed control are needed by many types of growers, but especially organic growers who are restricted from using synthetic herbicides. Abrasive grit made from corn cobs was expelled from a sand blaster at 517 kPa pressure and aimed at seedlings of common lambsquarters and corn...

  1. 29 CFR 1926.303 - Abrasive wheels and tools.

    Science.gov (United States)

    2010-07-01

    ... Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Tools-Hand and Power § 1926.303 Abrasive wheels and tools. (a) Power. All grinding machines shall be supplied with sufficient power to maintain...

  2. Three body abrasion of laser surface alloyed aluminium AA1200

    CSIR Research Space (South Africa)

    Mabhali, Luyolo AB

    2012-06-01

    Full Text Available on the composition of the alloying powder mixture. The wear performance of the alloyed surfaces was characterised using an ASTM G65 three body dry abrasion apparatus. A maximum 82% improvement in the wear resistance of the pure aluminium was achieved with a 40 wt% Ni...

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

    Indian Academy of Sciences (India)

    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.

  4. Gears castings from ductile iron of improved abrasion wear resistance

    Directory of Open Access Journals (Sweden)

    D. Kopyciński

    2011-10-01

    Full Text Available The aim of this study was to develop an industrial technological process for the manufacturing of castings from alloyed ductile iron characterized by improved resistance to abrasion wear. The outcome of the study was the implementation of developed technology under the industrial conditions of ASPAMET Foundry Plant and start up of production of a wide range of cast gears.

  5. Abrasive blasting agents: designing studies to evaluate relative risk.

    Science.gov (United States)

    Hubbs, Ann; Greskevitch, Mark; Kuempel, Eileen; Suarez, Fernando; Toraason, Mark

    Workers exposed to respirable crystalline silica used in abrasive blasting are at increased risk of developing a debilitating and often fatal fibrotic lung disease called silicosis. The National Institute for Occupational Safety and Health (NIOSH) recommends that silica sand be prohibited as abrasive blasting material and that less hazardous materials be used in blasting operations. However, data are needed on the relative risks associated with exposure to abrasive blasting materials other than silica. NIOSH has completed acute studies in rats (Hubbs et al., 2001; Porter et al., 2002). To provide dose-response data applicable to making recommendation for occupational exposure limits, NIOSH has collaborated with the National Toxicology Program (NTP) to design longer term studies with silica substitutes. For risk assessment purposes, selected doses will include concentrations that are relevant to human exposures. Rat lung burdens achieved should be comparable to those estimated in humans with working lifetime exposures, even if this results in "overloading" doses in rats. To quantify both dose and response, retained particle burdens in the lungs and lung-associated lymph nodes will be measured, as well as biochemical and pathological indices of pulmonary response. This design will facilitate assessment of the pulmonary fibrogenic potential of inhaled abrasive blasting agents at occupationally relevant concentrations.

  6. Brushing abrasion of luting cements under neutral and acidic conditions.

    Science.gov (United States)

    Buchalla, W; Attin, T; Hellwig, E

    2000-01-01

    Four resin based materials (Compolute Aplicap, ESPE; Variolink Ultra, Vivadent; C&B Metabond, Parkell and Panavia 21, Kuraray), two carboxylate cements (Poly-F Plus, Dentsply DeTrey and Durelon Maxicap, ESPE), two glass-ionomer cements (Fuji I, GC and Ketac-Cem Aplicap, ESPE), one resin-modified glass ionomer cement (Vitremer, 3M) one polyacid-modified resin composite (Dyract Cem, Dentsply DeTrey) and one zinc phosphate cement (Harvard, Richter & Hoffmann) were investigated according to their brushing resistance after storage in neutral and acidic buffer solutions. For this purpose 24 cylindrical acrylic molds were each filled with the materials. After hardening, the samples were stored for seven days in 100% relative humidity and at 37 degrees C. Subsequently, they were ground flat and polished. Then each specimen was covered with an adhesive tape leaving a 4 mm wide window on the cement surface. Twelve samples of each material were stored for 24 hours in a buffer solution with a pH of 6.8. The remaining 12 samples were placed in a buffer with a pH of 3.0. All specimens were then subjected to a three media brushing abrasion (2,000 strokes) in an automatic brushing machine. Storage and brushing were performed three times. After 6,000 brushing strokes per specimen, the tape was removed. Brushing abrasion was measured with a computerized laser profilometer and statistically analyzed with ANOVA and Tukey's Standardized Range Test (p < or = 0.05). The highest brushing abrasion was found for the two carboxylate cements. The lowest brushing abrasion was found for one resin based material, Compolute Aplicap. With the exception of three resin-based materials, a lower pH led to a higher brushing abrasion.

  7. Loose abrasive lapping hardness of optical glasses and its interpretation.

    Science.gov (United States)

    Lambropoulos, J C; Xu, S; Fang, T

    1997-03-01

    We present an interpretation of the lapping hardness of commercially available optical glasses in terms of a micromechanics model of material removal by subsurface lateral cracking. We analyze data on loose abrasive microgrinding, or lapping at fixed nominal pressure, for many commercially available optical glasses in terms of this model. The Schott and Hoya data on lapping hardness are correlated with the results of such a model. Lapping hardness is a function of the mechanical properties of the glass: The volume removal rate increases approximately linearly with Young's modulus, and it decreases with fracture toughness and (approximately) the square of the Knoop hardness. The microroughness induced by lapping depends on the plastic and elastic properties of the glass, depending on abrasive shape. This is in contrast to deterministic microgrinding (fixed infeed rate), where it is determined from the plastic and fracture properties of the glass. We also show that Preston's coefficient has a similar dependence as lapping hardness on glass mechanical properties, as well as a linear dependence on abrasive size for the case of brittle material removal. These observations lead to the definition of an augmented Preston coefficient during brittle material removal. The augmented Preston coefficient does not depend on glass material properties or abrasive size and thus describes the interaction of the glass surface with the coolant-immersed abrasive grain and the backing plate. Numerical simulations of indentation are used to locate the origin of subsurface cracks and the distribution of residual surface and subsurface stresses, known to cause surface (radial) and subsurface (median, lateral) cracks.

  8. Wear characterization of abrasive waterjet nozzles and nozzle materials

    Science.gov (United States)

    Nanduri, Madhusarathi

    Parameters that influence nozzle wear in the abrasive water jet (AWJ) environment were identified and classified into nozzle geometric, AWJ system, and nozzle material categories. Regular and accelerated wear test procedures were developed to study nozzle wear under actual and simulated conditions, respectively. Long term tests, using garnet abrasive, were conducted to validate the accelerated test procedure. In addition to exit diameter growth, two new measures of wear, nozzle weight loss and nozzle bore profiles were shown to be invaluable in characterizing and explaining the phenomena of nozzle wear. By conducting nozzle wear tests, the effects of nozzle geometric, and AWJ system parameters on nozzle wear were systematically investigated. An empirical model was developed for nozzle weight loss rate. To understand the response of nozzle materials under varying AWJ system conditions, erosion tests were conducted on samples of typical nozzle materials. The effect of factors such as jet impingement angle, abrasive type, abrasive size, abrasive flow rate, water pressure, traverse speed, and target material was evaluated. Scanning electron microscopy was performed on eroded samples as well as worn nozzles to understand the wear mechanisms. The dominant wear mechanism observed was grain pullout. Erosion models were reviewed and along the lines of classical erosion theories a semi-empirical model, suitable for erosion of nozzle materials under AWJ impact, was developed. The erosion data correlated very well with the developed model. Finally, the cutting efficiency of AWJ nozzles was investigated in conjunction with nozzle wear. The cutting efficiency of a nozzle deteriorates as it wears. There is a direct correlation between nozzle wear and cutting efficiency. The operating conditions that produce the most efficient jets also cause the most wear in the nozzle.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  10. CLINICO EPIDEMIOLOGICAL AND BIOCHEMICAL PROFILE OF PATIENTS WITH MELASMA

    Directory of Open Access Journals (Sweden)

    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

  11. Estudo critico do emprego de um escore clinico-laboratorial para a prescrição da digoxina

    OpenAIRE

    Zuttere, Dominique J. de

    2012-01-01

    Resumo: O objetivo deste trabalho ê aquilatar a eficiência do escore de NICHOLSON & DOBBS, método de auxílio ã prescrição da digoxina proposto em 1978. Em 58 pacientes externos ou internados, previamente digitalizados, são praticadas dosagens da digoxina sérica antes (1? fase) e após (2$ fase) um período de tratamento de 3 semanas sob o esquema posolõgico ditado pelo escore. Além da digoxina sérica, são levantados diversos outros parâmetros e variáveis de natureza clínicolaboratorial. O escor...

  12. Polineuropatia por Parathion: estudo clinico, eletrofisiológico e histológico de um caso

    Directory of Open Access Journals (Sweden)

    José L. Alonso

    1983-09-01

    Full Text Available Estudamos um paciente com quadro clínico rebelde, produzido por intoxicação pelo Parathion. Foi observado um fenômeno miotônico transitório, não descrito na literatura revisada. A constatação de cifras de AchE eritrocitária baixas e de colinesterase plasmática normais, indicou que era portador de déficit congênito de AchE, esclarecendo-se a evolução crônica do seu quadro. O fenômeno miotônico associado ao quadro clínico, eletrofisiológico, histológico e bioquímico fazem deste paciente um modelo clínico, de etiologia conhecida, da discutida síndrome de Isaacs.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

  14. Abrasive Wear Study of NiCrFeSiB Flame Sprayed Coating

    Science.gov (United States)

    Sharma, Satpal

    2013-10-01

    In the present study, abrasive wear behavior of NiCrFeSiB alloy coating on carbon steel was investigated. The NiCrFeSiB coating powder was deposited by flame spraying process. The microstructure, porosity and hardness of the coatings were evaluated. Elemental mapping was carried out in order to study the distribution of various elements in the coating. The abrasive wear behavior of these coatings was investigated under three normal loads (5, 10 and 15 N) and two abrasive grit sizes (120 and 320 grit). The abrasive wear rate was found to increase with the increase of load and abrasive size. The abrasive wear resistance of coating was found to be 2-3 times as compared to the substrate. Analysis of the scanning electron microscope images revealed cutting and plowing as the material removal mechanisms in these coatings under abrasive wear conditions used in this investigation.

  15. Abrasion Testing of Critical Components of Hydrokinetic Devices

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. A physically-based abrasive wear model for composite materials

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Gun Y.; Dharan, C.K.H.; Ritchie, Robert O.

    2001-05-01

    A simple physically-based model for the abrasive wear of composite materials is presented based on the mechanics and mechanisms associated with sliding wear in soft (ductile) matrix composites containing hard (brittle) reinforcement particles. The model is based on the assumption that any portion of the reinforcement that is removed as wear debris cannot contribute to the wear resistance of the matrix material. The size of this non-contributing portion of the reinforcement is estimated by modeling the three primary wear mechanisms, specifically plowing, interfacial cracking and particle removal. Critical variables describing the role of the reinforcement, such as its relative size and the nature of the matrix/reinforcement interface, are characterized by a single contribution coefficient, C. Predictions are compared with the results of experimental two-body (pin-on drum) abrasive wear tests performed on a model aluminum particulate-reinforced epoxy matrix composite material.

  17. Nanometric Finishing on Biomedical Implants by Abrasive Flow Finishing

    Science.gov (United States)

    Subramanian, Kavithaa Thirumalai; Balashanmugam, Natchimuthu; Shashi Kumar, Panaghra Veeraiah

    2016-01-01

    Abrasive flow finishing (AFF) is a non-conventional finishing technique that offers better accuracy, efficiency, consistency, economy in finishing of complex/difficult to machine materials/components and provides the possibility of effective automation as aspired by the manufacturing sector. The present study describes the finishing of a hip joint made of ASTM grade Co-Cr alloy by Abrasive Flow Machining (AFM) process. The major input parameters of the AFF process were optimized for achieving nanometric finishing of the component. The roughness average (Ra) values were recorded during experimentation using surface roughness tester and the results are discussed in detail. The surface finished hip joints were characterized using Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and residual stress analysis using X-Ray Diffraction (XRD). The discussion lays emphasis on the significance, efficacy and versatile nature of the AFF process in finishing of bio-medical implants.

  18. Optimization of Abrasive Water Jet Cutting of Ductile Materials

    Institute of Scientific and Technical Information of China (English)

    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.

  19. A study on magnetic abrasive deburring of dual micro pattern

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Dong Hyun; Kwak, Jae Seob [Dept. of Mechanical Engineering, Pukyong National University, Busan (Korea, Republic of)

    2016-12-15

    Studies on dual micro pattern are not established because of difficulty of its fabrication and deburring technology. In this investigation, a dual micro pattern which consists of a net pattern and a lenticular pattern was fabricated on a cylindrical workpiece by turning process. Magnetic abrasive deburring (MAD) was proposed as a deburring process in this study. Burr height defined by difference of its height and theoretical pattern height was measured as about 1 μm. It is one of the non-traditional machining methods utilizing flexible tool which consists of ferrous particle and abrasive powder. Hence, the aim of this investigation is to remove generated burr on the dual micro pattern. Burr at the dual micro pattern was removed through MAD, and a prediction equation of machined pattern height was derived. A deburring condition was optimized and verified by experiments. As a result, it was confirmed that dual micro pattern which has high shape accuracy was fabricated using MAD.

  20. Abrasive Wear of Alloyed Cast Steels Applied for Heavy Machinery

    Directory of Open Access Journals (Sweden)

    Studnicki A.

    2015-03-01

    Full Text Available In the paper the results and analysis of abrasive wear studies were shown for two grades of cast steels: low-alloyed cast steel applied for heavy machinery parts such as housing, covers etc. and chromium cast steels applied for kinetic nodes of pin-sleeve type. Studies were performed using the modified in Department of Foundry pin-on-disc method.

  1. Microstructure formation and properties of abrasion resistant cast steel

    OpenAIRE

    S. Parzych; Krawczyk, J.

    2010-01-01

    The so-called adamitic cast steels are characterised by a high abrasion resistance. These cast steels are of a pearlitic matrix with uniformly distributed hypereutectoid cementite precipitates. Apart from hypereutectoid cementite very often transformed ledeburite also occurs in the microstructure of these cast steels. Such cast steels contain chromium (app. 1 %) and nickel (app. 0.5 %) as alloy additions and sometimes their silicon content is increased. The presence of molybdenum is also perm...

  2. Shotcup petal abrasions in close range .410-caliber shotgun injuries.

    Science.gov (United States)

    Dowling, G P; Dickinson, J A; Cooke, C T

    1988-01-01

    Shotcup petal abrasions centered around a shotgun wound of entrance are generally thought to occur at a range of 30 to 90 cm. A suicidal .410-caliber shotgun injury of the right eye is described in which typical petal abrasions were noted around the entrance wound. However, significant soot deposition around the wound suggested that the range of fire was less than 30 cm and perhaps closer to 15 cm. Test-firing of the weapon and ammunition used by the decedent showed some spread of the shotcup petals at a range of 7.5 cm, progressing to maximum spread at 30 to 52.5 cm. Further testing with other .410 ammunition, containing shotcups, confirmed the spread of shotcup petals at ranges less than 30 cm, irrespective of manufacturer, shotshell length, and birdshot size. When a variety of shotguns were tested, it was found that one weapon with a very short barrel and cylinder bore did not exhibit petal spread until a range of 30 cm was reached. The remaining shotguns, with longer barrels and full choke, all demonstrated definite petal spread at a range of 12.5 cm. The long, narrow configuration of .410 shotcup petals may explain their early spread and the production of petal abrasions at ranges of less than 30 cm.

  3. Surface characterization of current composites after toothbrush abrasion.

    Science.gov (United States)

    Takahashi, Rena; Jin, Jian; Nikaido, Toru; Tagami, Junji; Hickel, Reinhard; Kunzelmann, Karl-Heinz

    2013-01-01

    The present study was designed to evaluate the surface roughness and the gloss of current composites before and after toothbrush abrasion. We assessed forty dimensionally standardized composite specimens (n=8/group) from five composites: two nanohybrids (i. e., IPS Empress Direct Enamel and IPS Empress Direct Dentin), two microhybrids (i. e., Clearfil AP-X and Filtek Z250) and one organically modified ceramics (Admira). All of the specimens were polished with 4000-grid silicon carbide papers. Surface roughness was measured with a profilometer and gloss was measured with a glossmeter before and after powered toothbrush abrasion with a 1:1 slurry (dentifrice/tap water) at 12,000 strokes in a toothbrush simulator. There was a significant increase in the surface roughness and a reduction in gloss after toothbrush abrasion in all of the composites except Clearfil AP-X (p<0.05). Simple regression analysis showed that there was not an association between the surface roughness and the gloss (R(2)=0.191, p<0.001).

  4. Development of underwater cutting system by abrasive water-jet

    Science.gov (United States)

    Demura, Kenji; Yamaguchi, Hitoshi

    1993-09-01

    The technology to cut objects in the ocean's depths with abrasive water jets was examined for possible application in view of the greater water depths and sophistication involved in work on the ocean floor today. A test model was developed to study this technology's safety and practicability. The test model was designed for use at great water depths and has functions and a configuration that are unlike equipment used on land. A continuous, stable supply of abrasive is a distinctive design feature. In land applications, there had been problems with plugged tubes and an uneven supply. For this reason, the abrasive was converted to slurry form, and a continuous pressurized tube pump system was adopted for supply to the nozzle head. Also, a hydraulic motor that does not employ oil or electric power was used to provide an underwater drive that is environment-friendly. The report outlines the technology's general design concept including its distinctive functions and its configuration for use at great depths, and the report provides great detail on the equipment.

  5. Correlation Between Particle Velocities and Conditions of Abrasive Waterjet Formation

    Science.gov (United States)

    Chen, Wei-Long

    1990-01-01

    The velocities of water and abrasive particles in abrasive waterjet(AWJ) were measured by the use of Laser Transit Anemometer(LTA). A setup for the velocity measurement was constructed and a statistical technique was used to improve the accuracy of the velocity determination. A comparison of the magnitude of velocities determined by LTA, Piezoelectric Force Transducer and Schlieren Photograph clearly indicates the feasibility of the use of LTA. The velocities of water and particles were measured for different diameters of water and slurry nozzles, abrasive mass flow rates and particle sizes. The performed experiments enabled us to evaluate the effects of conditions of jet formation on the particles velocities. An empirical equation for the prediction of particles velocities was constructed by the use of obtained results. The coefficient of correlation between experimental and computed results is equal to 0.93. The acquired information can be used to select the operational parameters in AWJ cutting. The obtained results also provide information on the acceleration mechanism of entrained particles, which may be used to improve the design of slurry nozzle.

  6. Characterization of Effective Parameters in Abrasive Waterjet Rock Cutting

    Science.gov (United States)

    Oh, Tae-Min; Cho, Gye-Chun

    2014-03-01

    The rock cutting performance of an abrasive waterjet is affected by various parameters. In this study, rock cutting tests are conducted with different energy (i.e., water pressure, traverse speed, and abrasive feed rate), geometry (i.e., standoff distance), and material parameters [i.e., uniaxial compressive strength (UCS)]. In particular, experimental tests are carried out at a long standoff distance (up to 60 cm) to consider field application. The effective parameters of the rock cutting process are identified based on the relationships between the cutting performance indices (depth, width, and volume) and parameters. In addition, the cutting efficiency is analyzed with effective parameters as well as different pump types and the number of cutting passes considering the concept of kinetic jet energy. Efficiency analysis reveals that the cutting depth efficiency tends to increase with an increase in the water pressure and traverse speed and with a decrease in the standoff distance and UCS. Cutting volume efficiency strongly depends on standoff distance. High efficiency of cutting volume is obtained at a long standoff distance regardless of the pump type. The efficiency analysis provides a realistic way to optimize parameters for abrasive waterjet rock excavation.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    Tan, Melissa H X; Hill, Robert G; Anderson, Paul

    2015-01-01

    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 cutting efficiency. In conclusion, Na0SR was more efficacious than alumina for air abrasion cutting of dentine.

  9. ACGT: advancing clinico-genomic trials on cancer - four years of experience.

    Science.gov (United States)

    Martin, Luis; Anguita, Alberto; Graf, Norbert; Tsiknakis, Manolis; Brochhausen, Mathias; Rüping, Stefan; Bucur, Anca; Sfakianakis, Stelios; Sengstag, Thierry; Buffa, Francesca; Stenzhorn, Holger

    2011-01-01

    The challenges regarding seamless integration of distributed, heterogeneous and multilevel data arising in the context of contemporary, post-genomic clinical trials cannot be effectively addressed with current methodologies. An urgent need exists to access data in a uniform manner, to share information among different clinical and research centers, and to store data in secure repositories assuring the privacy of patients. Advancing Clinico-Genomic Trials (ACGT) was a European Commission funded Integrated Project that aimed at providing tools and methods to enhance the efficiency of clinical trials in the -omics era. The project, now completed after four years of work, involved the development of both a set of methodological approaches as well as tools and services and its testing in the context of real-world clinico-genomic scenarios. This paper describes the main experiences using the ACGT platform and its tools within one such scenario and highlights the very promising results obtained.

  10. Solitary bone plasmacytoma: An interesting case report with unusual clinico-cytological features.

    Science.gov (United States)

    Saksena, Annapurna; Mahajan, Nidhi; Agarwal, Shipra; Jain, Shyama

    2014-07-01

    Solitary bone plasmacytoma (SBP) is a rare entity characterized by localized proliferation of monoclonal plasma cells primarily occurring in the axial skeleton without systemic involvement. Involvement of the distal extremity is unusual. In the absence of typical clinical presentation, diagnosis may not be suspected clinico-radiologically; hence, fine-needle aspiration cytology may help in early and definitive diagnosis, hastening meticulous diagnostic workup and appropriate management of these patients. Intracytoplasmic crystalline inclusions (CI) have been reported in multiple myeloma and lymphoproliferative disorders. The present case highlights unusual clinico-cytological features of SBP with primary involvement of humerus, progression to tibia, and presence of extracellular and intracytoplasmic CI in plasma cells, a morphologic finding not reported in SBP earlier.

  11. [Clinico-functional features of mitral valve prolapse in young military men].

    Science.gov (United States)

    Gorbachenko, A V; Shalimov, P M

    2008-01-01

    One hundred and sixty-six young military man with mitral valve prolapse (MVP) aged 19.2+/-0.8 years were examined. Complex system approach to health status was applied to study clinico-functional features of this condition in young military men. The study found that clinico-functional manifestations of MVP in young military men reflected a multifocal character of dysadaptation during the first stages of military service. Conditions of professional military activity potentiate permanent progress of crisp prolapse as well as the severity of mitral regurgitation, structural and functional myocardial alterations, and myocardial electric instability increasing in the presence of abnormal cardiac chords under the influence of a prominent vegetative dysfunction. The reserve of the cardiorespiratory system and the entire organism in military men with MVP was lowered. The study registered inadequate hemodynamic responses to functional orthostatic test and physical load test, typical for hyperventilation syndrome.

  12. Lipodistrofia ginoide : aspectos epidemiologicos clinicos histopatologicos e terapeuticos

    OpenAIRE

    Ana Beatris Rodrigues Rossi

    1996-01-01

    Resumo: Com os objetivos de estudar os aspectos clínicos, epidemiológicos e histopatológicos (derme) da lipodistrofia ginóide (L.D.G.) e avaliar a eficácia da terapêutica tópica, foi realizado um estudo observacional descritivo de um grupo de 75 mulheres, que participaram de um ensaio clínico duplo cego - placebo com um produto tópico. Como princípios ativos, foram empregados um vaso ativo (ginkgo biloba), um lipolítico (cafeína) e um trófico do tecido conjuntivo (centella asiática), além do ...

  13. Clinico-epidemiological Study and Quality of Life Assessment in Melasma

    OpenAIRE

    Ravali Yalamanchili; Veeranna Shastry; Jayadev Betkerur

    2015-01-01

    Background: Melasma is one of the most common and distressing pigmentary disorders presenting to dermatology clinics. The precise cause of melasma remains unknown. It is notably difficult to treat and has a tendency to relapse. Its population prevalence varies according to ethnic composition, skin phototype, and intensity of sun exposure. Due to its frequent facial involvement, the disease has an impact on the quality of life of patients. Aims: To study the clinico-epidemiological pattern,...

  14. [Autosomal-recessive renal cystic disease and congenital hepatic fibrosis: clinico-anatomic case].

    Science.gov (United States)

    Rostol'tsev, K V; Burenkov, R A; Kuz'micheva, I A

    2012-01-01

    Clinico-anatomic observation of autosomal-recessive renal cystic disease and congenital hepatic fibrosis at two fetuses from the same family was done. Mutation of His3124Tyr in 58 exon of PKHD1 gene in heterozygous state was found out. The same pathomorphological changes in the epithelium of cystic renal tubules and bile ducts of the liver were noted. We suggest that the autopsy research of fetuses with congenital abnormalities, detected after prenatal ultrasonic screening, has high diagnostic importance.

  15. [Clinico-epidemiological characteristics of transient cerebral ischemia in the region of the Ukrainian Carpathian Mountains].

    Science.gov (United States)

    Buletsa, B A; Lupich, P P; Litvinova, L A

    1991-01-01

    Altogether 225 patients with transitory derangements of cerebral circulation (TDCC) underwent clinico-laboratory examinations. Arterial hypertension and cerebral atherosclerosis turned out to be among most frequently occurring factors of TDCC. The provoking factors included psychoemotional stress and drops of barometric pressure. The course and outcome of TDCC were greatly affected by an increase in blood concentration of catecholamines and thyroid hormones. The high concentration of triiodothyronine in the blood contributed to the development of cerebral stroke.

  16. Impact–abrasion wear characteristics of in-situ VC-reinforced austenitic steel matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Moghaddam, E.G., E-mail: emad_g_moghaddam@alum.sharif.edu [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran (Iran, Islamic Republic of); Karimzadeh, N. [Department of Materials Engineering, Islamic Azad University, Najafabad Branch, Isfahan (Iran, Islamic Republic of); Varahram, N.; Davami, P. [Department of Materials Science and Engineering, Sharif University of Technology, P.O. Box 11365-9466, Azadi Avenue, Tehran (Iran, Islamic Republic of)

    2013-11-15

    In this investigation, in-situ precipitation of vanadium carbides was employed to reinforce Fe–13Mn and Fe–13Mn–3W alloys by means of conventional melting and casting route. Microstructures were characterized by optical and scanning electron microscopy techniques. Mechanical properties of the materials were determined by hardness, impact toughness and tension tests. It was observed that tungsten improved the strength of the matrix and the reinforcements as well as tensile properties and work hardening rate of the VC-reinforced composite. Ball mill abrasion test was utilized to simulate impact–abrasion wear condition using two types of abrasive minerals. The results showed that the degree of benefit to be gained by the use of in-situ VC-reinforced composite materials depends strongly on crush strength of the abrasives. It was found that the studied particle-reinforced composite materials were only advantageous when the abrasives were relatively soft, providing low-stress abrasion condition.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  18. um estudo de caso

    OpenAIRE

    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...

  19. A Profilometric Study to Assess the Role of Toothbrush and Toothpaste in Abrasion Process

    Directory of Open Access Journals (Sweden)

    Sandeep Kumar

    2015-09-01

    Full Text Available Statement of the Problem: Despite of many studies conducted on toothbrushes and toothpaste to find out the culprit for abrasion, there is no clear cut evidence to pin point the real cause for abrasion. Purpose: An in vitro assessment of the role of different types of toothbrushes (soft/ medium/hard in abrasion process when used in conjunction with and without a dentifrice. Materials and Method: Forty five freshly extracted, sound, human incisor teeth were collected for this study. Enamel specimens of approximately 9 mm2 were prepared by gross trimming of extracted teeth using a lathe machine (Baldor 340 Dental lathe; Ohio, USA. They were mounted on separate acrylic bases. The specimens were divided into three groups, each group containing 15 mounted specimens. Group 1 specimens were brushed with soft toothbrush; Group 2 brushed with medium toothbrush and Group 3 with hard toothbrush. Initially, all the mounted specimens in each group were brushed using dentifrice and then the same procedure was repeated with water as control. Profilometric readings were recorded pre and post to tooth brushing and the differences in readings served as proxy measure to assess surface abrasion. These values were then compared to each other. Kruskal Wallis and Mann-Whitney U test were performed. Results: The results showed that brushing, with water alone, caused less abrasion than when toothpaste was added (p< 0.008. When brushed with water, the harder toothbrush caused more abrasion (higher Ra-value, but when toothpaste was added, the softer toothbrush caused more abrasion (p< 0.001. Conclusion: Besides supporting the fact that toothpaste is needed to create a significant abrasion, this study also showed that a softer toothbrush can cause more abrasion than harder ones. The flexibility of bristles is only secondary to abrasion process and abrasivity of dentifrice has an important role in abrasion process.

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

    OpenAIRE

    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...

  1. The measurement of the velocity of abrasive particles at the suction part of the cutting head

    OpenAIRE

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

    2013-01-01

    To be able to optimize the design of the abrasive cutting head using numerical simulation, it is necessary to gather as much information about processes occurring in the cutting head as possible. The development of the numerical model of processes occurring in the abrasive water jet cutting head during the process of creation and forming of abrasive water jet is currently in progress at the Institute of Geonics in Ostrava. The verification of the model requires, among others, to determine the...

  2. Technical Possibilities of Noise Reduction in Material Cutting by Abrasive Water-jet

    OpenAIRE

    Radvanská, Agáta; Ergić, Todor; IVANDIĆ, Željko; Hloch, Sergej; Valiček, Jan; Mullerova, Jana

    2009-01-01

    The technical procedure of noise reduction in material cutting by abrasive water-jet is described in this paper. The paper is aimed at the implementation of technical possibilities of noise reduction in the cutting of material by abrasive water-jet technology. Both the theoretical and experimental investigations were performed to verify and specify the new findings in the reduction of acoustic sound pressure at abrasive water-jet machining of engineering materials. By means of identification,...

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

    OpenAIRE

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

    2015-01-01

    To be able to optimize the design of the abrasive cutting head using numerical simulation, it is necessary to gather as much information about processes occurring in the cutting head as possible. The development of the numerical model of processes occurring in the abrasive water jet cutting head during the process of creation and forming of abrasive water jet is currently in progress at the Institute of Geonics in Ostrava. The verification of the model requires, among others, to determine the...

  4. A Profilometric Study to Assess the Role of Toothbrush and Toothpaste in Abrasion Process.

    Science.gov (United States)

    Kumar, Sandeep; Kumar Singh, Siddharth; Gupta, Anjali; Roy, Sayak; Sareen, Mohit; Khajuria, Sarang

    2015-09-01

    Despite of many studies conducted on toothbrushes and toothpaste to find out the culprit for abrasion, there is no clear cut evidence to pin point the real cause for abrasion. An in vitro assessment of the role of different types of toothbrushes (soft/ medium/hard) in abrasion process when used in conjunction with and without a dentifrice. Forty five freshly extracted, sound, human incisor teeth were collected for this study. Enamel specimens of approximately 9 mm(2) were prepared by gross trimming of extracted teeth using a lathe machine (Baldor 340 Dental lathe; Ohio, USA). They were mounted on separate acrylic bases. The specimens were divided into three groups, each group containing 15 mounted specimens. Group 1 specimens were brushed with soft toothbrush; Group 2 brushed with medium toothbrush and Group 3 with hard toothbrush. Initially, all the mounted specimens in each group were brushed using dentifrice and then the same procedure was repeated with water as control. Profilometric readings were recorded pre and post to tooth brushing and the differences in readings served as proxy measure to assess surface abrasion. These values were then compared to each other. Kruskal Wallis and Mann-Whitney U test were performed. The results showed that brushing, with water alone, caused less abrasion than when toothpaste was added (p< 0.008). When brushed with water, the harder toothbrush caused more abrasion (higher Ra-value), but when toothpaste was added, the softer toothbrush caused more abrasion (p< 0.001). Besides supporting the fact that toothpaste is needed to create a significant abrasion, this study also showed that a softer toothbrush can cause more abrasion than harder ones. The flexibility of bristles is only secondary to abrasion process and abrasivity of dentifrice has an important role in abrasion process.

  5. A comparison of the abrasiveness of six ceramic surfaces and gold.

    Science.gov (United States)

    Jacobi, R; Shillingburg, H T; Duncanson, M G

    1991-09-01

    A type III gold alloy and six different ceramic surfaces were secured in an abrasion machine opposing extracted teeth to determine their relative abrasiveness and resistance to wear. The rankings of restorative materials from least abrasive to most abrasive were: gold alloy, polished; cast ceramic, polished; porcelain, polished; cast ceramic, polished and shaded; porcelain, polished and glazed; cast ceramic, cerammed skin shaded; and cast ceramic, cerammed skin unshaded. The ranking of materials from most wear-resistant to least wear-resistant was: gold alloy, cast ceramic cerammed, cast ceramic cerammed and shaded, porcelain polished, porcelain glazed, cast ceramic polished and shaded, and cast ceramic polished.

  6. Influence of the input parameters on the efficiency of plaster sanding with alundum abrasive discs

    Science.gov (United States)

    Krajcarz, D.; Spadło, S.; Młynarczyk, P.

    2017-02-01

    The paper presents test results concerning the relationship between selected input parameters and the process efficiency for the sanding of plaster surfaces with alundum abrasive discs. The input parameters under study were the size of the abrasive grains, the force exerted by the plaster sample pressing against the abrasive disc and the no-load rotational speed of the abrasive disc. The experimental data illustrating the relationship between the process efficiency and the particular input parameters were used to select the optimum plaster sanding conditions.

  7. EXPERIMENTAL STUDY ON VELOCITY PROFILE OF SUBMERGED ABRASIVE SUSPENSION JET FLOW

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Abrasive jet cutting, as a more efficient machining or cutting method, has emerged in recent years in mining and machining industries, but the knowledge about velocity profile of abrasive jet flow lacks in general. In practice, the Polyacrylamide (PAM) is generally applied to jet fluid to increase the suspension of the abrasive particles. Also, the effects of PAM on jet flow are not very clear. In this paper, velocity fields of both the abrasive particles and the fluid were systematically studied with the PIV technology. The slip velocity between the abrasive particle and the surrounding fluid was subtracted out to give a further description of abrasive suspension jet. The effects of polymer PAM on both the fluid flow and the movement of the suspending abrasive particles were also measured. And it is found that the PAM is a proper type of additive to improve velocity fields for both the abrasive particles and the fluid in a jet. The results of the PIV measurement can help give a better understanding about the basic physics of abrasive suspension jet flow, and a good guidance to validate and develop reliable computational models to describe the jet.

  8. RESEARCH ABOUT RESULTS REPRODUTIBILITY AND ABRASIVE PARTICLES FRAGMENTATION IN BALL-CRATERING TESTS

    Directory of Open Access Journals (Sweden)

    Ronaldo Câmara Cozza

    2013-06-01

    Full Text Available The micro-abrasive wear tests by rotating ball (crater wear have played an important role in abrasive wear researches. In this type of test, the contact between a specimen and a ball on rotating motion and abrasive particles supplied between these two elements, results in a crater on the specimen, based on which the abrasive wear behaviour is analysed. The purpose of this work is to study results the reprodutibility and the silicon carbide (SiC abrasive particles fragmentation during micro-abrasive wear tests. Tests were conducted with carburized AISI 1010 steel balls and high speed steel specimens, “with” and “without” titanium nitride (TiN coatings. The abrasive slurry was prepared with black silicon carbide (average particle size of 5 µm and distilled water. Grooving abrasion is related with lower reprodutibility results. For the test conditions of this work, no abrasive particles fragmentation was observed, independently of the sliding distance, what is justified, among others factors, by the low normal force applied.

  9. Experimental Study on Surface Roughness by Using Abrasive Particles

    Directory of Open Access Journals (Sweden)

    A.K.Chaitanya

    2017-06-01

    Full Text Available New advancement of technology and never satisfying demands of the civilization are putting huge pressure on the natural fuel resources and these resources are at a constant threat to its sustainability. Surface finish has a vital influence on functional properties such as wear resistance and power loss due to friction on most of the engineering components. Voltage, mesh number, revolutions per minute (rpm of electromagnet, and percentage weight of abrasives has been identified as important process parameters affecting surface roughness. The experiments were planned using response surface methodology and percentage change in surface roughness (ΔRa was considered as response. Analysis of experimental data showed that percentage change in surface roughness (ΔRa was highly influenced by mesh number followed by percentage weight of abrasives, rpm of electromagnet, and voltage. The process has been investigated extensively in the finishing of cylindrical surfaces. The surface finish was found to improve significantly with an increase in the grain size, relative size of abrasive particles vis-à-vis the iron particles, feed rate and current. Super finishing is a micro-finishing process that produces a controlled and smooth surface condition on work pieces. It is not primarily a sizing operation, its major purpose is to produce a surface on a work piece capable of sustaining uneven distribution of a load by improving the geometrical accuracy. The wear life of the parts micro finished to maximum smoothness is extended considerably. According to the design of experimentation, mathematical model for Lapping operation on advance ceramic material is proposed. In order to get minimum values of the surface roughness, optimization of the mathematical model is done and optimal operation of the examined factors is going to be determined. The obtained results will be, according to the experiment plan, valid for the testing of ceramic material by Lapping

  10. Surface roughness and wear of resin cements after toothbrush abrasion

    Directory of Open Access Journals (Sweden)

    Sérgio Kiyoshi ISHIKIRIAMA

    2015-01-01

    Full Text Available Increased surface roughness and wear of resin cements may cause failure of indirect restorations. The aim of this study was to evaluate quantitatively the surface roughness change and the vertical wear of four resin cements subjected to mechanical toothbrushing abrasion. Ten rectangular specimens (15 × 5 × 4 mm were fabricated according to manufacturer instructions for each group (n = 10: Nexus 3, Kerr (NX3; RelyX ARC, 3M ESPE (ARC; RelyX U100, 3M ESPE (U100; and Variolink II, Ivoclar/Vivadent (VL2. Initial roughness (Ra, µm was obtained through 5 readings with a roughness meter. Specimens were then subjected to toothbrushing abrasion (100,000 cycles, and further evaluation was conducted for final roughness. Vertical wear (µm was quantified by 3 readings of the real profile between control and brushed surfaces. Data were subjected to analysis of variance, followed by Tukey’s test (p < 0.05. The Pearson correlation test was performed between the surface roughness change and wear (p < 0.05. The mean values of initial/final roughness (Ra, µm/wear (µm were as follows: NX3 (0.078/0.127/23.175; ARC (0.086/0.246/20.263; U100 (0.296/0.589/16.952; and VL2 (0.313/0.512/22.876. Toothbrushing abrasion increased surface roughness and wear of all resin cements tested, although no correlation was found between those variables. Vertical wear was similar among groups; however, it was considered high and may lead to gap formation in indirect restorations.

  11. Optimization of Profile and Material of Abrasive Water Jet Nozzle

    Science.gov (United States)

    Anand Bala Selwin, K. P.; Ramachandran, S.

    2017-05-01

    The objective of this work is to study the behaviour of the abrasive water jet nozzle with different profiles and materials. Taguchi-Grey relational analysis optimization technique is used to optimize the value with different material and different profiles. Initially the 3D models of the nozzle are modelled with different profiles by changing the tapered inlet angle of the nozzle. The different profile models are analysed with different materials and the results are optimized. The optimized results would give the better result taking wear and machining behaviour of the nozzle.

  12. Assessment of abrasiveness for research of rock cutting

    Directory of Open Access Journals (Sweden)

    Milan Labaš

    2012-12-01

    Full Text Available Rock abrasiveness is ability of rock to wear down the working tool during the mutual interaction between the working indentorand the rock in the mechanical rock cutting process. The cutting indentor is worn down during the interaction, which changes itsgeometric dimensions causing the enlargement of a contact area between the tool and the rock surface. The changes in these dimensionsconsequently alter the rate of advance of the drilling machine and the specific cutting energy. We have determined the abrasivenessaccording to the norm ON 44 1121 (1982 on the testing device constructed at the Institute of Geotechnics SAS.

  13. Diffuse corneal abrasion after ocular exposure to laundry detergent pod.

    Science.gov (United States)

    Whitney, Rachel E; Baum, Carl R; Aronson, Paul L

    2015-02-01

    Although ocular injury from alkaline household cleaning products is well described, there is less known about the significance and extent of injury with ocular exposure to detergent pods. We report a 12-month-old with diffuse corneal abrasion caused by ocular contact with a laundry detergent pod. In addition to the known risks with aspiration with detergent pods, the potential for severe ocular injury is important for parents and clinicians to recognize. Children with ocular exposure to detergent pods should seek immediate medical care.

  14. Characteristics and mechanism of abrasive wear for thermoplastic polymers

    Institute of Scientific and Technical Information of China (English)

    Xian Jia; Xiaomei Ling

    2003-01-01

    Abrasive wear characteristics of polyethylene, polystyrene, polymethylmethacrylate, nylon 1010 and polyvinyl chloride were investigated. The volume relative wear resistance coefficients of these thermoplastic polymers are 18%-35 % (hardened and low temperature tempered steel 45 was used as a comparing material), and have a linear correlation with square roots of their cohesive energy densities. The coefficients of linear correlation is 0.949. Wear morphologies were observed by scanning electron microscope (SEM). Main wear mechanism of the thermoplastic polymers includes brittle breaking for the hard and brittle polymers & plowing and fatiguing for the soft and tough ones.

  15. Mechanical issues in laser and abrasive water jet cutting

    Science.gov (United States)

    Singh, Jogender; Jain, Sulekh C.

    1995-01-01

    In forging and other metal-working industries, lasers and abrasive water jets are being applied to cut a variety of metal products to improve productivity and reduce costs. As described in the following, both the processes have their unique cutting capabilities and characteristics. Before selecting one, however, users must be aware of how each technique influences the end product as well as its performance (e.g., high-cycle fatigue life). For this article, we examined the mechanics of these two cutting processes by studying their effects on Ti-6Al-4Vand A286 steel.

  16. Standard Test Method for Abrasive Wear Resistance of Cemented

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the determination of abrasive wear resistance of cemented carbides. 1.2 The values stated in inch-pound units are to be regarded as the standard. The SI equivalents of inch-pound units are in parentheses and may be approximate. 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.

  17. Adrenoleucodistrofia (leucodistrofia melanodermica: registro de um caso anatomo-clinico

    Directory of Open Access Journals (Sweden)

    Mario Wilson Iervolino Brotto

    1979-06-01

    Full Text Available É relatado o caso de um paciente de 14 anos, do sexo masculino, com esclerose cerebral difusa precedida em 7 anos de sinais de insuficiência do córtex supra-renal, com antecedentes familiares. Clinicamente a doença é caracterizada por deterioração mental, distúrbios da marcha e da visão, associados com insuficiência do córtex supra-renal. Confirmando os dados da literatura, em nosso caso o estudo anátomo-patológico revelou desmielinização e gliose difusa na substância branca cerebral, poupando as fibras subcorticais. Células inflamatórias são comuns e têm distribuição perivascular. Na zona fasciculada e reticular da supra-renal, células "balonadas" são evidentes, muitas delas apresentando citoplasma vacuolizado e com estriações. Inclusões lipídicas similares têm sido encontradas nas células de Schwann dos nervos periféricos e dos testículos. Os achados são comparados com vinte casos da literatura.

  18. Experimental Study on Abrasive Water Jet Machining of PZT Ceramic

    Science.gov (United States)

    Dhanawade, Ajit; Upadhyai, Ravi; Rouniyar, Arunkumar; Kumar, Shailendra

    2017-07-01

    This paper presents research work involved in abrasive water jet machining of PZT ceramic material. Process parameters namely stand-off distance, water pressure and traverse rate are considered in the present study. Response surface methodology approach is used to design the experiments. Relative significance of process parameters and their influence on kerf properties are identified on the basis of analysis of variance. It is found that water pressure and traverse rate are most significant parameters followed by stand-off distance. On the basis of experimental analysis, regression models are developed to predict kerf taper and depth of cut. The models are developed with respect to significant parameters, interaction and quadratic terms. It is found that model predictions are in congruence with experimental results. Multi-response optimization of process parameters is also performed using desirability approach in order to minimize kerf taper and maximize depth of cut. Kerf wall features of machined surfaces are observed using scanning electron microscope. The findings of present study are useful to improve kerf properties in abrasive water jet machining of PZT ceramic materials.

  19. Polyurethanes from the crystalline prepolymers resistant to abrasive wear

    Directory of Open Access Journals (Sweden)

    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.

  20. Abrasive Wear Map of Polymer Tapes in Sand Dust Environment

    Institute of Scientific and Technical Information of China (English)

    WU Tong-hai; DIAO Dong-feng

    2006-01-01

    To make clear the wear conditions of ATM (Automatic Teller Machine) tribosystem when servicing in Chinese sand dust environment, abrasive wear of two kinds of polymer tapes specified for ATM, PI (Polyimide) and PEN (Polyethylene-2, 6-naphthalenedicarboxylate), was investigated in simulated sand dust environment with ATM tape-scraper tribosystem under various conditions of loads and sliding distances. The surface profiles of worn tape were measured with a surface profiler in order to calculating the wear cross-section areas and the wear volumes. The specific wear rates of polymer tapes were calculated under load conditions of 0.6, 1 and 1.5 N, and wear mechanisms were investigated with optical topography photos. As main results, the specific wear rates show stage variations in the wear process and the wear resistance of polymer tape shows good relationship with the mechanical deformation factors. In consideration of the service life, four wear models are generalized according to the magnitude of specific wear rates,which include no wear, mild wear, normal wear and severe wear model and the corresponding wear mechanisms for the four wear models are discussed with typical worn topographies. Based on the wear models and corresponding wear mechanisms, the abrasive wear maps of two polymer tapes servicing in sand dust environments are concluded for its industrial applications.

  1. Study on mineral processing technology for abrasive minerals

    Energy Technology Data Exchange (ETDEWEB)

    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. Shrinkage, abrasion, erosion and sorption of clay plasters

    Directory of Open Access Journals (Sweden)

    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.

  3. Abrasive-assisted Nickel Electroforming Process with Moving Cathode

    Science.gov (United States)

    REN, Jianhua; ZHU, Zengwei; XIA, Chunqiu; QU, Ningsong; ZHU, Di

    2017-03-01

    In traditional electroforming process for revolving parts with complex profiles, the drawbacks on surface of deposits, such as pinholes and nodules, will lead to varying physical and mechanical properties on different parts of electroformed components. To solve the problem, compositely moving cathode is employed in abrasive-assisted electroforming of revolving parts with complicated profiles. The cathode translates and rotates simultaneously to achieve uniform friction effect on deposits without drawbacks. The influences of current density and translation speed on the microstructure and properties of the electroformed nickel layers are investigated. It is found that abrasive-assisted electroforming with compound cathode motion can effectively remove the pinholes and nodules, positively affect the crystal nucleation, and refine the grains of layer. The increase of current density will lead to coarse microstructure and lower micro hardness, from 325 HV down to 189 HV. While, faster translational linear speed produces better surface quality and higher micro hardness, from 236 HV up to 283 HV. The weld-ability of the electroformed layers are also studied through the metallurgical analysis of welded joints between nickel layer and 304 stainless steel. The electrodeposited nickel layer shows fine performance in welding. The novel compound motion of cathode promotes the mechanical properties and refines the microstructure of deposited layer.

  4. Abrasive-assisted Nickel Electroforming Process with Moving Cathode

    Science.gov (United States)

    REN, Jianhua; ZHU, Zengwei; XIA, Chunqiu; QU, Ningsong; ZHU, Di

    2017-03-01

    In traditional electroforming process for revolving parts with complex profiles, the drawbacks on surface of deposits, such as pinholes and nodules, will lead to varying physical and mechanical properties on different parts of electroformed components. To solve the problem, compositely moving cathode is employed in abrasive-assisted electroforming of revolving parts with complicated profiles. The cathode translates and rotates simultaneously to achieve uniform friction effect on deposits without drawbacks. The influences of current density and translation speed on the microstructure and properties of the electroformed nickel layers are investigated. It is found that abrasive-assisted electroforming with compound cathode motion can effectively remove the pinholes and nodules, positively affect the crystal nucleation, and refine the grains of layer. The increase of current density will lead to coarse microstructure and lower micro hardness, from 325 HV down to 189 HV. While, faster translational linear speed produces better surface quality and higher micro hardness, from 236 HV up to 283 HV. The weld-ability of the electroformed layers are also studied through the metallurgical analysis of welded joints between nickel layer and 304 stainless steel. The electrodeposited nickel layer shows fine performance in welding. The novel compound motion of cathode promotes the mechanical properties and refines the microstructure of deposited layer.

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

    Science.gov (United States)

    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.

  6. Modeling of Micro Deval abrasion loss based on some rock properties

    Science.gov (United States)

    Capik, Mehmet; Yilmaz, Ali Osman

    2017-10-01

    Aggregate is one of the most widely used construction material. The quality of the aggregate is determined using some testing methods. Among these methods, the Micro Deval Abrasion Loss (MDAL) test is commonly used for the determination of the quality and the abrasion resistance of aggregate. The main objective of this study is to develop models for the prediction of MDAL from rock properties, including uniaxial compressive strength, Brazilian tensile strength, point load index, Schmidt rebound hardness, apparent porosity, void ratio Cerchar abrasivity index and Bohme abrasion test are examined. Additionally, the MDAL is modeled using simple regression analysis and multiple linear regression analysis based on the rock properties. The study shows that the MDAL decreases with the increase of uniaxial compressive strength, Brazilian tensile strength, point load index, Schmidt rebound hardness and Cerchar abrasivity index. It is also concluded that the MDAL increases with the increase of apparent porosity, void ratio and Bohme abrasion test. The modeling results show that the models based on Bohme abrasion test and L type Schmidt rebound hardness give the better forecasting performances for the MDAL. More models, including the uniaxial compressive strength, the apparent porosity and Cerchar abrasivity index, are developed for the rapid estimation of the MDAL of the rocks. The developed models were verified by statistical tests. Additionally, it can be stated that the proposed models can be used as a forecasting for aggregate quality.

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

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Reflectorized Bicycle Wheel Rim Abrasion... HAZARDOUS SUBSTANCES ACT REGULATIONS REQUIREMENTS FOR BICYCLES Pt. 1512, Fig. 8 Figure 8 to Part 1512—Reflectorized Bicycle Wheel Rim Abrasion Test Device EC03OC91.074...

  8. Process monitoring evaluation and implementation for the wood abrasive machining process.

    Science.gov (United States)

    Saloni, Daniel E; Lemaster, Richard L; Jackson, Steven D

    2010-01-01

    Wood processing industries have continuously developed and improved technologies and processes to transform wood to obtain better final product quality and thus increase profits. Abrasive machining is one of the most important of these processes and therefore merits special attention and study. The objective of this work was to evaluate and demonstrate a process monitoring system for use in the abrasive machining of wood and wood based products. The system developed increases the life of the belt by detecting (using process monitoring sensors) and removing (by cleaning) the abrasive loading during the machining process. This study focused on abrasive belt machining processes and included substantial background work, which provided a solid base for understanding the behavior of the abrasive, and the different ways that the abrasive machining process can be monitored. In addition, the background research showed that abrasive belts can effectively be cleaned by the appropriate cleaning technique. The process monitoring system developed included acoustic emission sensors which tended to be sensitive to belt wear, as well as platen vibration, but not loading, and optical sensors which were sensitive to abrasive loading.

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

    Science.gov (United States)

    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 ...

  10. Cutting Tools, Files and Abrasives. Pre-Apprenticeship Phase 1 Training.

    Science.gov (United States)

    Lane Community Coll., Eugene, OR.

    This self-paced student training module on cutting tools, files, and abrasives is one of a number of modules developed for Pre-apprenticeship Phase 1 Training. Purpose of the module is to enable students to identify and explain the proper use and care of various knives, saws, snips, chisels, and abrasives. The module may contain some or all of the…

  11. Electron Microscopy Abrasion Analysis of Candidate Fabrics for Planetary Space Suit Protective Overgarment Application

    Science.gov (United States)

    Hennessy, Mary J.

    1992-01-01

    The Electron Microscopy Abrasion Analysis of Candidate Fabrics for Planetary Space Suit Protective Overgarment Application is in support of the Abrasion Resistance Materials Screening Test. The fundamental assumption made for the SEM abrasion analysis was that woven fabrics to be used as the outermost layer of the protective overgarment in the design of the future, planetary space suits perform best when new. It is the goal of this study to determine which of the candidate fabrics was abraded the least in the tumble test. The sample that was abraded the least will be identified at the end of the report as the primary candidate fabric for further investigation. In addition, this analysis will determine if the abrasion seen by the laboratory tumbled samples is representative of actual EVA Apollo abrasion.

  12. Two-Body Abrasive Wear of the Surfaces of Pangolin Scales

    Institute of Scientific and Technical Information of China (English)

    Jin Tong; Tie-biao Lü; Yun-hai Ma; Heng-kun Wang; Lu-quan Ren; R. D. Arnell

    2007-01-01

    The Pangolin, a soil-burrowing animal, is covered with scales. These scales are often abraded by soil and rock and their surface is corrugated. The abrasive wear of the surface of the scales was examined. The scales were taken from a pangolin that had died of natural causes. The tests were run on a rotary disc abrasive wear tester. The abrasive material was quartz sand (96.5 wt.%) and bentonite (3.5 wt.%). The morphology of the abraded surfaces and the abrasion were examined by stereoscopic microscopy and scanning electron microscopy. The concepts are proposed of "Guiding-Effect" and "Rolling-Effect" on the textured surfaces under free abrasive wear conditions and the critical dimensions of the "Rolling-Effect" are discussed.

  13. A review of engineering control technology for exposures generated during abrasive blasting operations.

    Science.gov (United States)

    Flynn, Michael R; Susi, Pam

    2004-10-01

    This literature review presents information on measures for controlling worker exposure to toxic airborne contaminants generated during abrasive blasting operations occurring primarily in the construction industry. The exposures of concern include respirable crystalline silica, lead, chromates, and other toxic metals. Unfortunately, silica sand continues to be widely used in the United States as an abrasive blasting medium, resulting in high exposures to operators and surrounding personnel. Recently, several alternative abrasives have emerged as potential substitutes for sand, but they seem to be underused Some of these abrasives may pose additional metal exposure hazards. In addition, several new and improved technologies offer promise for reducing or eliminating exposures; these include wet abrasive blasting, high-pressure water jetting, vacuum blasting, and automated/robotic systems. More research, particularly field studies, is needed to evaluate control interventions in this important and hazardous operation.

  14. A new method to test rock abrasiveness based on physico-mechanical and structural properties of rocks

    Directory of Open Access Journals (Sweden)

    V.N. Oparin

    2015-06-01

    Full Text Available A new method to test rock abrasiveness is proposed based upon the dependence of rock abrasiveness on their structural and physico-mechanical properties. The article describes the procedure of presentation of properties that govern rock abrasiveness on a canonical scale by dimensionless components, and the integrated estimation of the properties by a generalized index. The obtained results are compared with the known classifications of rock abrasiveness.

  15. A new method to test rock abrasiveness based on physico-mechanical and structural properties of rocks

    Institute of Scientific and Technical Information of China (English)

    V.N. Oparin; A.S. Tanaino

    2015-01-01

    abstract A new method to test rock abrasiveness is proposed based upon the dependence of rock abrasiveness on their structural and physico-mechanical properties. The article describes the procedure of presentation of properties that govern rock abrasiveness on a canonical scale by dimensionless components, and the integrated estimation of the properties by a generalized index. The obtained results are compared with the known classifications of rock abrasiveness.

  16. Investigation of the abrasive lapping of oxide ceramics

    Directory of Open Access Journals (Sweden)

    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

  17. Clinico-epidemiologichesky aspects of the mixed tick-borne infections in the endemic region

    Directory of Open Access Journals (Sweden)

    E. S. Aleshkovskaya

    2013-01-01

    Full Text Available Detection of clinico-epidemiological features of the mixed tick-borne infections – tick-borne Lyme disease and a human granulocytic anaplasmosis was the purpose of the conducted research. During the spring – summer period 146 patients with tick-borne borreliosis were surveyed. As a result at 45 (30,82% patients authentically diagnosed the mixed tick-borne infection. Features of clinical manifestations of a mixed tick-borne infection revealed: catarrhal phenomena (20%, liver defeats (33%, nephros (31, 7%, frequent secondary erythems (20%. Changes in haemogram defined: thrombocytopenia (42,2%, anemia (20%, leukopenia (13,3%.

  18. Peripheral odontogenic fibroma: a rare gingival neoplasm with clinico-pathological differential diagnosis.

    Science.gov (United States)

    Kumar, Rajesh; Jaiswal, Shradha; Sharma, Aanchal; Andhare, Vinod; Sabir, Husain

    2015-01-01

    The peripheral odontogenic fibroma (POdF) is a rare gingival neoplasm, characterised by relatively mature collagenous fibrous tissue and varying amounts of odontogenic epithelium. It can be described as a slow growing, firmly attached, solid and smooth gingival mass which may be present asymptomatically for years, which may cause displacement of adjacent teeth. The purpose of this article is to discuss a case of POdF, occurring in the maxillary anterior region, with detailed clinico-pathological differential diagnosis to clarify characteristic features of various gingival overgrowths to enhance easy identification.

  19. Behavioral symptoms after pallido-nigral lesions: a clinico-pathological case.

    Science.gov (United States)

    Adam, Julien; Baulac, Michel; Hauw, Jean-Jacques; Laplane, Dominique; Duyckaerts, Charles

    2008-01-01

    A 59-year-old patient presented with compulsive behaviors and lasting apathy after carbon monoxide intoxication. The apathy could be overcome by external stimulation (self-activation deficit). There was severe neuronal loss bilaterally in the anterior part of the pallidum and in the substantia nigra, pars reticulata. This first clinico-pathological case of a self-activation deficit illustrates the dissociation between motor and behavioral symptoms in lesions of the pallido-nigral complex, with the behavioral symptoms being related to lesions of the substantia nigra, pars reticulata and of the anterior part of the pallidum.

  20. [Clinico-epidemiological characteristics of mentally ill patients identified in the therapy department].

    Science.gov (United States)

    Liberman, Iu I; Ostroglazov, V G; Lisina, M A; Eliava, V N

    1990-01-01

    A clinico-epidemiological study was made of the incidence of mental diseases among the adult community visiting the therapeutic department of a city polyclinic. Mental patients registered at the PND (41.9 per 1000 population) underwent examinations. A large group of patients, mainly with borderline mental diseases, was additionally revealed (134.4 per 1000 population). Therefore, the total incidence of mental diseases among the adult community amounted to 176.3 per 1000 population. Both groups are compared in terms of the clinical syndromes, sex, age, and the level of social adaptation.

  1. Implementation of revised strategy of filaria control-baseline clinico-parasitological survey.

    Science.gov (United States)

    Patel, S; Rai, R N; Mishra, R N

    2000-06-01

    A clinico-epidemiological study of filariasis was carried out in Varanasi District in October and November, 1997 to generate baseline data for assessing the impact of Mass Drug Administration (MDA) in the district. Disease rate was found to be 6.6% (9.9% in males and 3.0% in females) and microfilaria rate was 5.3% (5.2% in males and 5.5% in females). Mean microfilaria density was found to be 9.86 per 20 Cu.mm blood. Genital manifestations (77.5%) outnumbered all other forms of clinical manifestations. Vector infectivity rate was found to be 0.93%.

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

    Directory of Open Access Journals (Sweden)

    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.

  3. Standard test method for jaw crusher gouging abrasion test

    CERN Document Server

    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.)

  4. Surface quality of marble machined by abrasive water jet

    Directory of Open Access Journals (Sweden)

    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.

  5. Monitoring and control of fine abrasive finishing processes

    DEFF Research Database (Denmark)

    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...... of this work was to investigate foundations for process monitoring and control methods in application to semi-automated polishing machine based on the industrial robot. The monitoring system was built on NI data acquisition system with two sensors, acoustic emission sensor and accelerometer. Acquired sensory...... signals were analysed in time-frequency domain and specific process features are extracted in relation to machining parameters and processed surface properties. Development and research of the process monitoring was done with background in evaluation of surface roughness parameters. The characterization...

  6. Mars rover rock abrasion tool performance enhanced by ultrasonic technology.

    Science.gov (United States)

    Macartney, A.; Li, X.; Harkness, P.

    2016-12-01

    The Mars exploration Athena science goal is to explore areas where water may have been present on the early surface of Mars, and investigate the palaeo-environmental conditions of these areas in relation to the existence of life. The Rock Abrasion Tool (RAT) designed by Honeybee Robotics has been one of four key Athena science payload instruments mounted on the mechanical arm of the Spirit, Opportunity and Curiosity Mars Exploration Rovers. Exposed rock surfaces weather and chemically alter over time. Although such weathered rock can present geological interest in itself, there is a limit to what can be learned. If the geological history of a landing site is to be constructed, then it is important to analyse the unweathered rock interior as clearly as possible. The rock abrasion tool's role is to substitute for a geologist's hammer, removing the weathered and chemically altered outer surface of rocks in order to view the pristine interior. The RAT uses a diamond resin standard common grinding technique, producing a 5mm depth grind with a relatively high surface roughness, achieved over a number of hours per grind and consumes approximately 11 watts of energy. This study assesses the benefits of using ultrasonic assisted grinding to improve surface smoothness. A prototype Micro-Optic UltraSonic Exfoliator (MOUSE) is tested on a range of rock types and demonstrates a number of advantages over the RAT. In addition to a smoother grind finish, these advantages include a lower rate of tool tip wear when using a tungsten carbide tip as opposed to diamond resin, less moving parts, a grind speed of minutes instead of hours, and a power consumption of only 1-5 Watts.

  7. Cover and Erosion Asymmetry in Saltation-Abrasion

    Science.gov (United States)

    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.

  8. An Investigation of Abrasive Wear Behaviour of Al 2014-SiC Composites

    Science.gov (United States)

    Çalin, Recep; Cilasun, Niyazi Selçuk

    2015-04-01

    In this study, the effects of SiC reinforcement volume fractions on hardness, porosity and abrasive wear behaviour were examined in Al 2014-SiC (composites (MMCs) of 3%, 6% and 12% reinforcement-volume (R-V) ratios produced by melt-stirring. Abrasive wear tests were carried out by 320 mesh Al2O3 abrasive paper and a pin-on-disc wear test apparatus, under 10N, 20N and 30N load, and at 0.2 ms-1 sliding speed. The same specimens were tested by 150, 240 and 320 mesh abrasive paper at 0.2 ms-1 sliding speed, under 10N, 20N and 30N load. After the tests, the microstructures of the worn surfaces were examined with scanning electron microscope (SEM) studies and EDS analyses. Besides, the amount of hardness and porosity of the specimens were identified. It was recorded that the amounts of hardness and porosity increases as the SiC reinforcement in the composite increases. The highest amount of abrasive wear was recorded in the specimens with 3% reinforcements. It was identified that the amount of abrasive wear decreases while the SiC reinforcement in the composite structure increases by volume, and that the amount of porosity and reinforcement volume (R-V) ratio are important parameters in abrasive wear.

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

    Directory of Open Access Journals (Sweden)

    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.

  10. [Leptospirosis-clinico-biological and therapeutical aspects-study of 256 cases].

    Science.gov (United States)

    Luca, Mihaela Cătălina; Dorobăţ, Carmen; Corcaci, Carmen; Scurtu, Roxana; Luca, V; Mihalache, Doina

    2002-01-01

    Leptospirosis is a zooantroponosis manifested as an infectious disease with a severe evolution, with liver and renal failure and hemorrhagic manifestation. The aim of this study was to present the clinico-biological investigation and the therapeutical aspects of 256 cases of leptospirosis admitted in the Infectious Diseases Hospital Iasi during 4 years (1998-2001). The diagnosis was based on the study of clinico-biological and therapeutical parameters (risk factors, fever, mialgia, headache, algic, eruptive, meningeal, hepatorenal, hemorrhagic syndromes with the serological evidence of the serotypes of leptospirosis); most of the cases were registered in 1998 (23% cases), in adults (31.2%) and male (75.22%). All the patients were serologic confirmed with leptospirosis (RAL and RFC), and L. icterohaemorhagiae was isolated most frequently. The standard anti-leptospirosis treatment was administered with favorable evolution; 6 deaths were registered from the severe forms of the disease. The leptospirosis is an emergent disease with the possibility of severe evolution in some forms, with liver and renal failure.

  11. Clinico-pathological correlates of cervical lymphadenopathy: a hospital based study.

    Science.gov (United States)

    Biswas, Gautam; Das, Anjan; Haldar, Dibakar; Mukherjee, Ankur; Dutta, Sirshak; Sinha, Ramanuj

    2013-07-01

    Neck is the most common site of peripheral lymph node enlargement and is very frequently encountered in oto-laryngological practice. This study was done to delineate distribution of clinico-demographic parameters in patients presenting with cervical lymphadenopathy in the otolaryngology out-patient department of a state hospital in India in a 1 year period and to correlate them with fine needle aspiration cytological diagnosis. Record-based cross sectional study in the department of Otolaryngology and department of Pathology, Calcutta National Medical College and Hospital, Kolkata. Case reports and cytological reports of 423 patients who underwent Fine Needle Aspiration Cytology (FNAC) of cervical lymph nodes between January 2009 and December 2009 were reviewed in relation to their demographic and clinical profiles. The cases were divided into three groups according to age and different parameters were described according to these groups. In the cyto-pathological diagnosis, tubercular lymph-adenitis was most prevalent diagnosis (45.4%). Among the metastatic secondaries, squamous cell carcinoma was most common (8.5%). Non-specific/reactive lymphadenitis was significantly more common in clinico-demographic perspectives of cervical lymphadenopathy in respect to their cytopathological diagnosis will help care giver practioners to detect/refer the respective cases early for investigations and treatment.

  12. Carcinoma ex pleomorphic adenoma in a Brazilian population: clinico-pathological analysis of 38 cases.

    Science.gov (United States)

    Mariano, F V; Noronha, A L F; Gondak, R O; Altemani, A M de A M; de Almeida, O P; Kowalski, L P

    2013-06-01

    Carcinoma ex pleomorphic adenoma (CXPA) is a rare tumour, with different prevalence rates reported among studies. Epidemiological studies of large series of CXPAs in developing countries are scarce. The aim of the present study was to describe Brazilian patients with CXPA; this was a retrospective study of 38 patients. Demographic and clinico-pathological features were evaluated. No preferential gender was found, and the mean age at diagnosis was 57.6 years. The most commonly involved site was the parotid, followed by the submandibular and the minor salivary glands. A prevalence of clinical stages III and IV was observed at diagnosis. The most common histological subtypes were salivary duct carcinoma, adenocarcinoma not otherwise specified, myoepithelial carcinoma, and epithelial-myoepithelial carcinoma. Moreover, by invasive phase, most were frankly invasive carcinoma. Recurrence was observed in seven out of 24 patients with outcome information available, and all were invasive cases. All seven patients died of causes related to the disease. The distributions of cases according to age, gender, tumour location, and clinical stage were similar to those reported in the literature. Frankly invasive cases presented a worse prognosis. More information is needed to further our understanding of the clinico-pathological aspects of CXPA.

  13. Intestinal congenital/infantile fibrosarcoma: a new clinico-pathological entity?

    Science.gov (United States)

    Berrebi, Dominique; Fournet, Jean-Christophe; Boman, Françoise; Fabre, Monique; Philippe-Chomette, Pascale; Branchereau, Sophie; Fréneaux, Paul; Bouron-Dal Soglio, Dorothée; Michon, Jean; Peuchmaur, Michel

    2015-04-01

    Congenital/infantile fibrosarcoma (IFS) is a relatively rare form of fibrosarcoma diagnosed at birth or during early years of life and that differs from its adult counterpart because of a more favorable behavior. IFS is also known as cellular congenital mesoblastic nephroma, when it affects the kidney and is often but not always characterized by the ETV6-NTRK3 fusion transcript. We report herein the first series of an exceptional tumor of the small intestine occurring in newborns. The four patients shared a stereotyped clinico-pathological presentation with early and acute onset, intestinal perforation, and an infiltration by a highly cellular spindle cell tumor within the dilated intestinal wall exhibiting pathologic features typical of IFS. Molecular studies for the ETV6-NTRK3 translocation were negative in the three cases tested. Patients were treated by surgical wide resection alone and are alive and well (follow-up: 36 months-25 years). Thus, this new clinico-pathological entity, even with lack of documented evidence of the ETV6-NTRK3 translocation, should be included in the differential diagnosis of congenital bowel perforation or obstruction and may represent an intestinal counterpart of IFS.

  14. Abrasion behavior of graphite pebble in lifting pipe of pebble-bed HTR

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Ke; Su, Jiageng [Institute of Nuclear and New Energy Technology, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 10084 (China); Zhou, Hongbo [Institute of Nuclear and New Energy Technology, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 10084 (China); Chinergy Co., LTD., Beijing 100193 (China); Peng, Wei; Liu, Bing [Institute of Nuclear and New Energy Technology, Advanced Nuclear Energy Technology Cooperation Innovation Center, The Key Laboratory of Advanced Nuclear Engineering and Safety, Ministry of Education, Beijing 10084 (China); Yu, Suyun, E-mail: suyuan@tsinghua.edu.cn [Center for Combustion Energy, The Key Laboratory for Thermal Science and Power Engineering, Ministry of Educations, Tsinghua University, Beijing 10084 (China)

    2015-11-15

    Highlights: • Quantitative determination of abrasion rate of graphite pebbles in different lifting velocities. • Abrasion behavior of graphite pebble in helium, air and nitrogen. • In helium, intensive collisions caused by oscillatory motion result in more graphite dust production. - Abstract: A pebble-bed high-temperature gas-cooled reactor (pebble-bed HTR) uses a helium coolant, graphite core structure, and spherical fuel elements. The pebble-bed design enables on-line refueling, avoiding refueling shutdowns. During circulation process, the pebbles are lifted pneumatically via a stainless steel lifting pipe and reinserted into the reactor. Inevitably, the movement of the fuel elements as they recirculate in the reactor produces graphite dust. Mechanical wear is the primary source of graphite dust production. Specifically, the sources are mechanisms of pebble–pebble contact, pebble–wall (structural graphite) contact, and fuel handling (pebble–metal abrasion). The key contribution to graphite dust production is from the fuel handling system, particularly from the lifting pipe. During pneumatic lift, graphite pebbles undergo multiple collisions with the stainless steel lifting pipe, thereby causing abrasion of the graphite pebbles and producing graphite dust. The present work explored the abrasion behavior of graphite pebble in the lifting pipe by measuring the abrasion rate at different lifting velocities. The abrasion rate of the graphite pebble in helium was found much higher than those in air and nitrogen. This gas environment effect could be explained by either tribology behavior or dynamic behavior. Friction testing excluded the possibility of tribology reason. The dynamic behavior of the graphite pebble was captured by analysis of the audio waveforms during pneumatic lift. The analysis results revealed unique dynamic behavior of the graphite pebble in helium. Oscillation and consequently intensive collisions occur during pneumatic lift, causing

  15. Abrasion properties of homogenous and blended fill materials during pressure hydraulic transport

    Energy Technology Data Exchange (ETDEWEB)

    Turchaninov, S.P.

    1978-03-01

    A description is given of tests conducted to determine the abrasive properties of small and large-grain free-flowing fill materials during hydraulic transport of the materials under pressure. Data are given on the size, density, abrasiveness of various sized varieties of rock, sand, and blends comprising homogenous materials, simple and complex mixtures, and on the physical characteristics of various fill materials in relation to the trafficability and parameters of pipelines. Technical specifications are given for fill steel pipes. The study indicates that the durability of hydraulic fill pipelines largely depends on the abrasiveness of the fill materials. 3 references, 2 figures, 2 tables.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  18. Study on planarization machining of sapphire wafer with soft-hard mixed abrasive through mechanical chemical polishing

    Science.gov (United States)

    Xu, Yongchao; Lu, Jing; Xu, Xipeng

    2016-12-01

    This study investigated the material removal mechanism of sapphire wafer with soft-hard mixed abrasives through mechanical chemical polishing (MCP). The polishing film, which contains diamond as hard abrasives and high reactivity silica as soft abrasives, is prepared through sol-gel technology. Silica abrasives with regular spherical shape and high reactivity are prepared through hydrolysis-precipitation. Diamond grits with three different particle sizes are used as abrasives. Results show that the rate of material removal of mixed abrasives during MCP is more than 52.6% of that of single hard abrasives and the decrease in surface roughness is more than 21.6% of that of single hard abrasives. These results demonstrate that the ideal planarization of sapphire wafer with high removal rate and good surface quality can be achieved when the effect of mechanical removal of hard abrasives and the chemical corrosion effect of soft abrasives are in dynamic equilibrium. A model that describes the material removal mechanism of sapphire with mixed abrasives during MCP is proposed. The results of thermodynamic calculation and polishing residue analysis are used to demonstrate the rationality of the model.

  19. Surface assessment and modification of concrete using abrasive blasting

    Science.gov (United States)

    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

  20. Study of kerf geometry of multilayers materials in abrasive water jet cutting process

    Directory of Open Access Journals (Sweden)

    Barabas Bogdan

    2017-01-01

    Full Text Available The use of abrasive jet cutting in case of multilayers materials, shows particularities and difficulties, due to different hardness and thickness of layers. This paper studies changes, occurred in the kerf geometry at passing of abrasive particles, through layers with different hardness and aims to establish a link between hardness and thickness of the layers and kerf geometry because processing accuracy is determined by the geometry of the cut. Thus, is proposed a novel algorithm based on minimization of angle of kerf, for optimization a cutting process in abrasive water jet technology, which can be utilized for materials with different hardness in layers. Direct effect of optimization of cutting consist in increasing efficiency, dimensional precision, traverse velocity, and decreasing the amount of used abrasive garnet.

  1. Abrasive wear property of laser melting/deposited Ti2Ni/TiNi intermetallic alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A wear resistant intermetallic alloy consisting of TiNi primary dendrites and Ti2Ni matrix was fabricated by the laser melting deposition manufacturing process. Wear resistance of Ti2Ni/TiNi alloy was evaluated on an abrasive wear tester at room temperature under the different loads. The results show that the intermetallic alloy suffers more abrasive wear attack under low wear test load of 7, 13 and 25 N than high-chromium cast-iron. However, the intermetallic alloy exhibits better wear resistance under wear test load of 49 N. Abrasive wear of the laser melting deposition Ti2Ni/TiNi alloy is governed by micro-cutting and plowing.Pseudoelasticity of TiNi plays an active role in contributing to abrasive wear resistance.

  2. MAGNETO-ABRASIVE MACHINING OF SURFACES FORMED BY ELECTROMAGNET SURFACING WITH PLASTIC DEFORMATION

    Directory of Open Access Journals (Sweden)

    Zh. A. Mrochek

    2011-01-01

    Full Text Available The paper presents investigation results pertaining to magneto-abrasive machining of product surfaces formed by electromagnet surfacing with a plastic deformation of P6M5K5 powder. 

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

    Science.gov (United States)

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

    2012-10-01

    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 laser, semiconductor diode laser, and CO2 laser have been employed for removal of melanin hyper pigmentation. The following case series describes three different surgical depigmentation techniques: scalpel surgery, abrasion with rotary abrasive, and a diode laser. Better results of depigmentation were achieved with diode laser than conventional scalpel and with rotary abrasion with respect to esthetics. The results point out that lasers are an effective and a safe means to removal of hyperpigmentation from the gingiva. Healing was uneventful and no repigmentation occurred.

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

    Science.gov (United States)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  6. The effect of anti-sensitivity dentifrices on brushing abrasion of eroded dentin in vitro.

    Science.gov (United States)

    Hughes, Nathan; Mason, Stephen; Creeth, Jonathan; Hara, Anderson T; Parmar, Madhu; González-Cabezas, Carlos

    2008-01-01

    To investigate the abrasive effects of three marketed anti-sensitivity, and one marketed regular dentifrice on dentin, using an erosion-abrasion in vitro model. Standardized human dentin specimens were prepared and exposed to cycles of erosion, remineralization, and tooth brushing, utilizing the four commercially available dentifrices. Dentin surface loss was then measured by optical profilometry after a total of nine complete cycles. The RDA and pH values of the dentifrices were also measured to assist in the interpretation of results. Profilometry showed significantly greater dentin surface loss for both Colgate Sensitive Fresh Stripe and Colgate Sensitive Multi Protection when compared with Sensodyne Total Protection or Crest Cavity Protection dentifrices. The abrasive level of dentifrices correlated positively (r-squared = 0.66; p < 0.05) with dentin surface loss. This study demonstrated that the abrasivity of dentifrices can have a significant effect on the wear of eroded dentin in vitro.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  9. The effect on cast post dimensions of casting investment and airborne particle abrasion.

    Science.gov (United States)

    Hashem, Danya; German, Matthew J; Wassell, Robert W

    2011-09-01

    Cast posts can sometimes prove difficult to seat fully during fitting. This study compared two different liquid/water dilutions for phosphate bonded investment and the effect of controlled airborne particle abrasion on resulting post diameter. After measuring polymeric post patterns (n = 18), 3 groups were invested using concentrated solution and 3 groups using dilute solution. After casting they were weighed and remeasured then exposed to airborne particle abrasion. Both solutions produced oversized cast posts. Mean diameter reduction during airborne particle abrasion was 8 microm/10s taking an average of 41s to reach precast size. Where a post pattern fits tightly, airborne particle abrasion for 70s should reduce the casting sufficiently to accommodate the cement lute.

  10. Drawing Light-fields: Hand-drawn Approaches to Abrasion Holography

    Science.gov (United States)

    Duke, T.

    2013-02-01

    Abrasion holography has received little attention since the technique was described by William J. Beaty in the early 1990's. In this paper the limitations of abrasion holography are explored, and new approaches are presented which expand the possibilities of the medium. New tools presented here offer new possibilities to the artist wishing to draw holograms by hand. Methods are described by which complex curves and organic forms can be constructed by hand more easily and intuitively than previously described. In an analysis of reconstruction lighting and viewing geometries, new solutions to reduce or eliminate distortions are suggested. Various tools, materials, and scratch geometries are considered for optimum 3D illusion. A new class of abrasion holograms is presented that use elliptical, hypotrochoidal, and epitrochoidal scratch geometries, exhibiting novel animation effects. In conclusion, a method for embossing abrasion holograms with the aid of an etching press is described.

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

    CERN Document Server

    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.

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

    Science.gov (United States)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  14. Effect of dried sunflower seeds on incisal edge abrasion: A rare case report.

    Science.gov (United States)

    Rath, Avita; Ramamurthy, Priyadarshini H; Fernandes, Bennete Aloysius; Sidhu, Preena

    2017-01-01

    Tooth surface loss (TSL) is a complex phenomenon characterized by the loss of hard tooth structure at various locations of the teeth, usually due to more than one factor. TSL due to abrasion can be significant in patients consuming coarse, abrasive diet. The present case reports an interesting incisal edge abrasion in a female patient, attributed to a particular dietary behavior of long-term consumption of sunflower seeds. All her family members and most of the people from her native place were also reported to have similar lesions by the patient. Larger epidemiological studies to assess the prevalence and severity of such abrasive lesions in geographic areas with this particular dietary habit need to be carried out so that people may be made aware and educated about alternative ways of eating sunflower seeds that will not cause any form of tooth wear.

  15. Machining of the Flat Surfaces with Abrasive-metallic Lapping Tools

    Institute of Scientific and Technical Information of China (English)

    Adam Barylski

    2004-01-01

    The constructional principle of abrasion metal disc is that abrasive insertions are spread uniformly on the working surface of a metal base. During lapping by means of such tools only the machining fluid is dosed and that by drop.Abrasive elements of circular shape pellets are produced by mixing boron carbide BC400 micrograins with electrographite components, the pellets were pressed with a load of about 12 kN. Next they were heated in furnace at about 520K for hours,then cooled together with the furnace. Tests were carried out on the making of circular abrasive insertions of which the main components were born carbide and micrograins of electric copper mixed the epoxide resins.

  16. Machining of the Flat Surfaces with Abrasive-metallic Lapping Tools

    Institute of Scientific and Technical Information of China (English)

    AdamBarylski

    2004-01-01

    The constructional principle of abrasion metal disc is that abrasive insertions are spread uniformly on the working surface of a metal base. During lapping by means of such tools only the machining fluid is dosed and that by drop. Abrasive elements of circular shape pellets are produced by mixing boron carbide BC400 micrograins with electrographite components, the pellets were pressed with a load of about 12 kN. Next they were heated in furnace at about 520K for hours, then cooled together with the furnace. Tests were carried out on the making of circular abrasive insertions of which the main components were born carbide and micrograins of electric copper mixed the epoxide resins.

  17. A Study of effect of Process Parameters of Abrasive jet machining

    Directory of Open Access Journals (Sweden)

    Jagtar Singh

    2011-01-01

    Full Text Available As Abrasive jet machining (AJM is similar to sand blasting and effectively removes hard and brittle materials. AJM has been applied to rough working such as deburring and rough finishing. With the increase of needs for machining of ceramics, semiconductors, electronic devices and L.C.D., AJM has become a useful technique for micromachining. This paper deals with various experiments which were conducted to assess the influence of abrasive jet machining (AJM process parameters on material removal rate and diameter of holes of glass plates using aluminum oxide type of abrasive particles. The experimental results of the present work are used to discuss thevalidity of proposed model as well as the other models. With the increase in nozzle tip distance (NTD, the top surface diameter and bottom surface diameter of hole increases as it is in general observation of abrasive jet machining process. As the pressure increases, the material removal rate (MRR is also increased.

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

    Directory of Open Access Journals (Sweden)

    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.

  19. Specification of rock abrasiveness for the purposes of tunnel driving using TBM

    Directory of Open Access Journals (Sweden)

    Miklúšová Viera

    2000-09-01

    Full Text Available This article analyses rock abrasiveness that causes attrition (wearing down of the disintegration indentors. In the case of drilling machines equipped with disc chipper tools it is the attrition of the discs. The attrition of the discs results in the reduction of the drilling rate and the increase in the specific disintegration energy, thus directly affecting the total economic outcome of the mining site (tunnel.Abrasiveness of the rock is the rock’s ability to wear down the working tool during the mutual interaction between the working indentor and the rock in the mechanic rock disintegration process. The disintegration indentor wears down during the interaction, that changes its geometric dimensions, causing the increase in the contact area between the tool and the surface of the rock. The changes in these dimensions consequently alter the rate of advance of the drilling machine and the specific disintegration energy.Abrasiveness is therefore an overall result of physical and mechanical characteristics of the rock during the interaction between the disintegration indentor and the rock. In the present time there is no method that would formulate the rock’s abrasiveness at the hands of physical-mechanical characteristics of the rock. Because the interaction between the tool and the rock depends on the characteristics of the tool, abrasiveness is at present a relative quantity, dependent also on the quality of the disintegration indentors. With the progress in the quality of disintegration tools, the abrasiveness and the attrition of the tool during mechanic rock disintegration changes. From this standpoint it is, in the course of determining the rock’s abrasiveness in the laboratory procedures, needed to eliminate the impact of the disintegration indentor characteristics. By choosing one disintegration indentor type with predetermined physical-mechanical characteristics for the laboratory measurements, we can obtain abrasiveness that

  20. Multi-objective Optimization of Process Performances when Cutting Carbon Steel with Abrasive Water Jet

    Directory of Open Access Journals (Sweden)

    M. Radovanović

    2016-12-01

    Full Text Available Multi-objective optimization of process performances (perpendicularity deviation, surface roughness and productivity when cutting carbon steel EN S235 with abrasive water jet is presented in this paper. Cutting factors (abrasive flow rate, traverse rate and standoff distance were determined when perpendicularity deviation and surface roughness are minimal and productivity is maximal. Multi-objective genetic algorithm (MOGA was used for the determination set of nondominated optimal points, known as Pareto front.

  1. The influence of mixing water and abrasives on the quality of machined surface

    Directory of Open Access Journals (Sweden)

    A. Stoić

    2014-04-01

    Full Text Available This paper shows the impact of mixing water and abrasives in water jet cutting process on the quality of the machined surface. The tests were done with polymer material SIPAS, where the influence of cutting parameters was researched (cutting pressure, cutting feed and abrasive mass flow. The surface roughness was measured on several zones, regarding the depth of materials, because the roughness is increased with the material thickness.

  2. Ice Abrasion and Bond Testing of Repair Mortars and High Performance Concrete

    OpenAIRE

    Kirkhaug, Joakim Rydningen

    2013-01-01

    The purpose of this thesis has been to investigate ice abrasion properties for three different repair mortars, and evaluate their behavior and properties in relation to a typical B60 offshore concrete and a B70 concrete. Bond strength to a B60 concrete has been tested for all mortars. To increase understanding and knowledge in the field of research, a literature study was made. Roughness parameters, bond strength properties and parameters affecting ice abrasion resistance were reviewed. Testi...

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

    Institute of Scientific and Technical Information of China (English)

    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.

  4. Release of copper-amended particles from micronized copper-pressure-treated wood during mechanical abrasion

    OpenAIRE

    Civardi, Chiara; Schlagenhauf, Lukas; Kaiser, Jean-Pierre; Hirsch, Cordula; Mucchino, Claudio; Wichser, Adrian; Wick, Peter; Schwarze, Francis W. M. R.

    2016-01-01

    Background We investigated the particles released due to abrasion of wood surfaces pressure-treated with micronized copper azole (MCA) wood preservative and we gathered preliminary data on its in vitro cytotoxicity for lung cells. The data were compared with particles released after abrasion of untreated, water (0% MCA)-pressure-treated, chromated copper (CC)-pressure-treated wood, and varnished wood. Size, morphology, and composition of the released particles were analyzed. Results Our resul...

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

    Directory of Open Access Journals (Sweden)

    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.

  6. Microstructure formation and properties of abrasion resistant cast steel

    Directory of Open Access Journals (Sweden)

    S. Parzych

    2010-01-01

    Full Text Available The so-called adamitic cast steels are characterised by a high abrasion resistance. These cast steels are of a pearlitic matrix with uniformly distributed hypereutectoid cementite precipitates. Apart from hypereutectoid cementite very often transformed ledeburite also occurs in the microstructure of these cast steels. Such cast steels contain chromium (app. 1 % and nickel (app. 0.5 % as alloy additions and sometimes their silicon content is increased. The presence of molybdenum is also permissible (app. 0.4 %. The basic problem in application of these steels for structural elements constitutes their insufficient crack resistance. An improvement of mechanical properties by changes of morphology of hypereutectoid cementite and transformed ledeburite precipitates by means of the heat treatment application was the aim of this study. G200CrNiMo4-3-3 cast steel was the investigated material. Changes in the morphology of hypereutectoid cementite and transformed ledeburite obtained due to the heat treatment are described in detail in the present paper. An influence of the microstructure changes on impact toughness of the investigated cast steel is presented. Investigations performed within this study will serve for the microstructure optimisation on account of functional qualities of this cast steel.

  7. Laboratory Measurements of Particulate Matter Concentrations from Asphalt Pavement Abrasion

    Science.gov (United States)

    Fullová, Daša; Đurčanská, Daniela

    2016-12-01

    The issue of emissions from road traffic is compounded by the fact that the number of vehicles and driven kilometres increase each year. Road traffic is one of the main sources of particulate matter and traffic volume is still increasing and has unpleasant impact on longevity of the pavements and the environment. Vehicle motions cause mechanical wearing of the asphalt pavement surface - wearing course by vehicle tyres. The contribution deals with abrasion of bituminous wearing courses of pavements. The asphalt mixtures of wearing courses are compared in terms of mechanically separated particulate matter. The samples of asphalt mixtures were rutted in wheel tracking machine. The particulate matter measurements were performed in laboratory conditions. The experimental laboratory measurements make it possible to sample particulates without contamination from exhaust emissions, abraded particles from vehicles, resuspension of road dust and climate affects. The contribution offers partial results of measurements on six trial samples of asphalt mixtures with different composition. It presents particulate matter morphology and the comparison of rutted asphalt samples in terms of PM mass concentrations and chemical composition.

  8. Neutralization of potential land mine hazards by abrasive waterjet use

    Science.gov (United States)

    Summers, David A.; Fossey, Robert D.; Thompson, S. J.

    1998-09-01

    A method of neutralizing landmines in which the integrity of the surrounding terrain is retained is herein described. High pressure waterjets which can be used to detect the presence of landmines can then be used to remove the soil and other cover in a plane immediately adjacent to and around the mine so that the side of the mine can be visually inspected through a remote television camera. At that time the flow of water is channeled through a line in which small particles of sand are added to the waterjet which is at a pressure of between 3,000 and 10,000 psi depending on the device which is used. Jet flow rates are on the order of 5 gpm depending on the nozzle configuration used. By bringing this abrasive stream in along a lateral plane through the mine it is possible to intersect, and neutralize, the fusing systems most likely to be used to initiate the charge, in a single pass. At higher flow rates, as the cut is made the jet will generate significant turbulence in the mine body, sufficient to remove a considerable quantity of the explosive which is resident within the mine at the same time as the mine is being dissected. The precision of cut achievable is shown by the longitudinal cutting into two parts of live detonators, as well as representative mine bodies.

  9. Laboratory Measurements of Particulate Matter Concentrations from Asphalt Pavement Abrasion

    Directory of Open Access Journals (Sweden)

    Fullová Daša

    2016-12-01

    Full Text Available The issue of emissions from road traffic is compounded by the fact that the number of vehicles and driven kilometres increase each year. Road traffic is one of the main sources of particulate matter and traffic volume is still increasing and has unpleasant impact on longevity of the pavements and the environment. Vehicle motions cause mechanical wearing of the asphalt pavement surface - wearing course by vehicle tyres. The contribution deals with abrasion of bituminous wearing courses of pavements. The asphalt mixtures of wearing courses are compared in terms of mechanically separated particulate matter. The samples of asphalt mixtures were rutted in wheel tracking machine. The particulate matter measurements were performed in laboratory conditions. The experimental laboratory measurements make it possible to sample particulates without contamination from exhaust emissions, abraded particles from vehicles, resuspension of road dust and climate affects. The contribution offers partial results of measurements on six trial samples of asphalt mixtures with different composition. It presents particulate matter morphology and the comparison of rutted asphalt samples in terms of PM mass concentrations and chemical composition.

  10. Optimisation of Heat Treatment for Steel Stressed by Abrasive Erosive Degradation

    Directory of Open Access Journals (Sweden)

    Jiří Votava

    2016-01-01

    Full Text Available The aim of the present publication is the analysis of refined steels designed for conditions with increased abrasive stress (102Cr6, 54SiCr6, 25CrMo4 and 15230 – does not have DIN equivalent. These include mainly mechanical components used as replaceable parts in machines for tillage, such as plough blades and chisels. The experimental part is focused on the issue of heat treatment of steel materials, which are usually used for the production of machine parts intended for tools designed to withstand abrasive stress. The suitability of individual materials for the production of tools for tillage will be evaluated based on the results of mechanical tests. These include the analysis of the structure of the given material, its hardness (ČSN EN ISO 6508-1 and impact toughness (ČSN EN 10045-1. Microhardness of individual structural components was also measured. The analysis was processed on a metallographic microscope. The individual tests of abrasive resistance are divided between interaction of two objects and a combination of abrasive erosive wear. Laboratory tests were performed on an abrasive cloth (ČSN 01 5084 and in Bond’s drum apparatus (this experiment is not standardized. Based on the results of the individual measurements it is possible to make recommendation of a suitable heat treatment of tested materials for environments with considerable abrasive stress.

  11. Effect of Brushing Time and Dentifrice Abrasiveness on Color Change and Surface Roughness of Resin Composites.

    Science.gov (United States)

    Roselino, Lourenço de Moraes Rego; Chinelatti, Michelle Alexandra; Alandia-Román, Carla Cecilia; Pires-de-Souza, Fernanda de Carvalho Panzeri

    2015-10-01

    Dentifrice abrasiveness and brushing time may increase color change (∆E) and surface roughness (∆Ra) of resin composites. This study aimed to evaluate the effect of mechanical brushing time of dentifrices with different abrasiveness on ∆E and ∆Ra of nanofilled (Z350, 3M ESPE) and nanohybrid (Tetric N-Ceram, Ivoclar Vivadent) resin composites. Sixteen specimens (12 mm diameter x 2 mm thick) were fabricated using a white Teflon matrix of each resin composite and a ceramic (IPS e.max Ceram, Ivoclar Vivadent), used as control. After initial color readouts on white backgrounds (Spectrophotometer PCB 6807, Byk Gardner), with D65 standard illuminant, and surface roughness (Rugosimeter Surfcorder SE 1700, Kosalab) with cut-off=0.8 mm and speed=0.25 mm/s, specimens were assigned (n=8) according to the abrasiveness of the dentifrices: RDA* 68 (Colgate) and RDA* 180 (Colgate Total Plus Whitening). Specimens were submitted to mechanical brushing (58,400 cycles) and after every 14,600 cycles (1 year of brushing by a healthy individual), new color and surface roughness readouts were taken. Color stability was calculated by CIEDE2000. Data were analyzed by 3-way repeated measures ANOVA and Bonferroni test (pdentifrice abrasiveness (p=0.02) and brushing time (pdentifrice abrasiveness, the greater the color change of the nanofilled resin composite. The surface roughness was not influenced by dentifrice abrasiveness.

  12. Dynamic Mechanical Analysis and Three-Body Abrasive Wear Behaviour of Thermoplastic Copolyester Elastomer Composites

    Directory of Open Access Journals (Sweden)

    Hemanth Rajashekaraiah

    2014-01-01

    Full Text Available Various amounts of short fibers (glass and carbon and particulate fillers like polytetrafluoroethylene (PTFE, silicon carbide (SiC, and alumina (Al2O3 were systematically introduced into the thermoplastic copolyester elastomer (TCE matrix for reinforcement purpose. The mechanical properties such as storage modulus, loss modulus, and Tan δ by dynamic mechanical analysis (DMA and three-body abrasive wear performance on a dry sand rubber wheel abrasion tester have been investigated. For abrasive wear study, the experiments were planned according to L27 orthogonal array by considering three factors and three levels. The complex moduli for TCE hybrid composites were pushed to a higher level relative to the TCE filled PTFE composite. At lower temperatures (in the glassy region, the storage modulus increases with increase in wt.% of reinforcement (fiber + fillers and the value is maximum for the composite with 40 wt.% reinforcement. The loss modulus and damping peaks were also found to be higher by the incorporation of SiC and Al2O3 microfillers. The routine abrasive wear test results indicated that TCE filled PTFE composite exhibited better abrasion resistance. Improvements in the abrasion resistance, however, have not been achieved by short-fiber and particlaute filler reinforcements. From the Taguchi’s experimental findings, optimal combination of control factors were obtained for minimum wear volume and also predictive correlations were proposed. Further, the worn surface morphology of the samples was discussed.

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

    Science.gov (United States)

    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.

  14. Kinetic energy density and agglomerate abrasion rate during blending of agglomerates into powders.

    Science.gov (United States)

    Willemsz, Tofan A; Hooijmaijers, Ricardo; Rubingh, Carina M; Tran, Thanh N; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

    2012-01-23

    Problems related to the blending of a cohesive powder with a free flowing bulk powder are frequently encountered in the pharmaceutical industry. The cohesive powder often forms lumps or agglomerates which are not dispersed during the mixing process and are therefore detrimental to blend uniformity. Achieving sufficient blend uniformity requires that the blending conditions are able to break up agglomerates, which is often an abrasion process. This study was based on the assumption that the abrasion rate of agglomerates determines the required blending time. It is shown that the kinetic energy density of the moving powder bed is a relevant parameter which correlates with the abrasion rate of agglomerates. However, aspects related to the strength of agglomerates should also be considered. For this reason the Stokes abrasion number (St(Abr)) has been defined. This parameter describes the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. The St(Abr) number is shown to predict the abrasion potential of agglomerates in the dry-mixing process. It appeared possible to include effects of filler particle size and impeller rotational rate into this concept. A clear relationship between abrasion rate of agglomerates and the value of St(Abr) was demonstrated. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Microstructure and abrasion wear behavior of Ni-based laser cladding alloy layer at high temperature

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; LIU Su-qin; WANG Shun-xing

    2005-01-01

    Ni-based alloy coating on 21-4-N heat-resistant steel was prepared using CO2 laser, and the high-temperature abrasion wear was tested. The microstructure of this cladding layer and its abrasion wear behavior at high temperature by changing compositions and temperatures were investigated by means of optical microscope and scanning electron microscope. Among the three compositions of cladding layer, i.e. Ni21+20%WC+0.5%CeO2, Ni25+20%WC+0.5%CeO2 and Ni60+20%WC+0.5%CeO2, the experimental results show that Ni21+20%WC+0.5%CeO2 cladding layer is made up of finer grains, and presents the best abrasion wear behavior at high temperature. The wear pattern of laser cladding layer is mainly grain abrasion at lower temperature, and it would be changed to adhesive abrasion and oxide abrasion at higher temperature.

  16. Clinico-pathological analysis referring hemeoxygenase-1 in acute fibrinous and organizing pneumonia patients

    Directory of Open Access Journals (Sweden)

    Yu Hara

    2015-01-01

    We experienced two cases of subacute form AFOP for these 10 years and reviewed clinico-pathological characteristics. The average age was 62 years old and both were male. The etiology of both cases was idiopathic. The average PaO2/FIO2 ratio was 274.5 ± 84.1. The average levels of C-reactive protein and surfactant protein - A of the serum were elevated to 19.8 ± 6.3 mg/dL and 67.6 ± 15.8 ng/mL, respectively. Serum sialylated carbohydrate antigen levels were normal in both cases. The characteristic radiographic findings were bilateral consolidations and ground glass opacities. Lung biopsy specimens revealed fibrin balls and alveolitis with abundant cellular HO-1 expression. Steroid response was excellent and the pulmonary involvements absolutely disappeared for about 3 months.

  17. [Clinico-economical aspects of cardioversion of paroxysmal atrial fibrillation at phehospital stage and during hospitalization].

    Science.gov (United States)

    Bulanova, N A; Stazhadze, L L; Sidorenko, B A

    2012-01-01

    We carried out clinico-economical analysis of 2 tactics of rhythm restoration in patients with paroxysmal atrial fibrillation (AF) lasting less than 48 hours: cardioversion at prehospital stage with intravenous procainamide and inhospital cardioversion with any method. This retrospective study was based on the data from department of urgent aid of an outpatient clinic. The results showed that within 48 hours inhospital was a was more effective, safe, and more economically profitable compared with administration of procainamide at prehospital stage. Intravenous procainamide resulted in effective cardioversion in 70.6% of patients. It was associated with arterial hypotension and proarrhythmogenic action in 14,7% of cases. Patients with effective cardioversion with procainamide had lesser mean values of left ventricular anterior-posterior dimension (echocardiography) and shorter duration of arrhythmia.

  18. Pulmonary Alveolar Microlithiasis "Stone Lungs": A Case of Clinico-Radiological Dissociation.

    Science.gov (United States)

    Chu, Andrew; Shaharyar, Sameer; Chokshi, Binna; Bhardwaj, Nikhil

    2016-08-24

    Pulmonary alveolar microlithiasis (PAM) is a rare infiltrative lung disease characterized by deposition of spherical calcium phosphate microliths called calcospherites within the alveoli. PAM was first described by Friedrich in 1856 and then by Harbitz in 1918. The disease pathogenesis is based on mutations in the SLC34A2 gene that encodes for the Type IIb sodium-phosphate cotransporter. The majority of the patients are diagnosed at an early age, usually between the ages of 20 and 40 years. The hallmark of this disease is a striking dissociation between the radiological findings and the mild clinical symptoms.  We report a case of 35-year-old woman who presented post-motor vehicle accident with back pain and with minimal dyspnea on exertion. The final diagnosis was made after computed tomography and lung biopsy. The present case exhibits the remarkable clinico-radiological dissociation with complete calcification of the lungs on radiographic images with a relatively mild clinical presentation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Tajima, Yasutaka; Homma, Sanae; Sinpo, Kazunori; Moriwaka, Fumio; Tashiro, Kunio (Hakodate City Hospital, Hokkaido (Japan)); Maruo, Yasunori

    1994-03-01

    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).

  20. Behavior of HVOF WC-10Co4Cr Coatings with Different Carbide Size in Fine and Coarse Particle Abrasion

    Science.gov (United States)

    Ghabchi, Arash; Varis, Tommi; Turunen, Erja; Suhonen, Tomi; Liu, Xuwen; Hannula, S.-P.

    2010-01-01

    A modified ASTM G 65 rubber wheel test was employed in wet and dry conditions using 220 nm titania particles and 368 μm sand particles, respectively. Both tests were conducted on WC-CoCr coatings produced with two powders with different carbide grain sizes (conventional and sub-micron) to address the effect of carbide size and abrasive medium characteristics on the wear performance. The same spot before and after the wet abrasion wear testing was analyzed in detail using SEM to visualize wear mechanisms. It was shown that the wear mechanism depends on the relative size of the carbide and abrasive particles. Wear mechanisms in dry sand abrasion were studied by analyzing the single scratches formed by individual abrasive particles. Interaction of surface open porosity with moving abrasive particles causes formation of single scratches. By tailoring the carbide size, the wear performance can be improved.

  1. Performance of Flame Sprayed Ni-WC Coating under Abrasive Wear Conditions

    Science.gov (United States)

    Harsha, S.; Dwivedi, D. K.; Agarwal, A.

    2008-02-01

    This paper describes the influence of a post spray heat treatment on the microstructure, microhardness and abrasive wear behavior of the flame sprayed Ni-WC (EWAC 1002 ET) coating deposited on the mild steel. Coatings were deposited by using an oxy-acetylene flame spraying torch (Superjet Eutalloy L & T, India). The wear behavior of the coating was evaluated using a pin on disc wear system against SiC abrasive medium of 120 and 600 grades at 5, 10, 15, and 20 N normal load. Results revealed that the influence of normal load on wear is governed by the microstructure, hardness and abrasive grit size. The heat treatment increased average microhardness of the coating. However, it was found that the hardness does not correctly indicate the abrasive wear resistance of Ni-WC coating in an as sprayed and heat treated condition. The heat treatment of the coating improved its abrasive wear resistance against fine abrasive medium while the wear resistance against coarse abrasive was found to be a function of a normal load. At low-normal load (5 and 10 N) the heat treated coating showed lower-wear rate than as spayed coating while at high-normal loads (15 and 20 N) heat treated coating was subjected to higher-wear rate than as sprayed coating. In general, an increase in normal load increased the wear rate. The scanning electron microscopy study indicated that the wear largely takes place by groove formation and scoring of eutectic matrix and the fragmentation of the carbide particles.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    Leonardo Stephan CAPOROSSI

    2016-01-01

    Full Text Available Abstract 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 < 0.001, irrespective of the toothbrush type tested. End-rounded bristles therefore removed plaque more effectively without 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.

  6. Comparing Effects of Four Toothpaste Types (Nasim, Crest 7, Crest Sensitivity and Daroghar3) on Rate of Enamel Abrasion

    OpenAIRE

    2016-01-01

    Introduction: Toothpaste should have the most plaque removal efficacy with the least abrasiveness. The aim of this study was to evaluate enamel abrasion induced by four toothpaste types. Methods: In this in vitro experimental study, 24 dental samples were divided into four groups of six. The initial surface roughness was measured with the roughness measuring device. Regarding abrasion test with Daroghar3, Nasim, Crest7 and Crest sensitivity toothpastes, samples were located in V8cross brus...

  7. A profilometry-based dentifrice abrasion Method for V8 brushing machines. Part I: Introduction to RDA-PE.

    Science.gov (United States)

    White, Donald J; Schneiderman, Eva; Colón, Ellen; St John, Samuel

    2015-01-01

    This paper describes the development and standardization of a profilometry-based method for assessment of dentifrice abrasivity called Radioactive Dentin Abrasivity - Profilometry Equivalent (RDA-PE). Human dentine substrates are mounted in acrylic blocks of precise standardized dimensions, permitting mounting and brushing in V8 brushing machines. Dentin blocks are masked to create an area of "contact brushing." Brushing is carried out in V8 brushing machines and dentifrices are tested as slurries. An abrasive standard is prepared by diluting the ISO 11609 abrasivity reference calcium pyrophosphate abrasive into carboxymethyl cellulose/glycerin, just as in the RDA method. Following brushing, masked areas are removed and profilometric analysis is carried out on treated specimens. Assessments of average abrasion depth (contact or optical profilometry) are made. Inclusion of standard calcium pyrophosphate abrasive permits a direct RDA equivalent assessment of abrasion, which is characterized with profilometry as Depth test/Depth control x 100. Within the test, the maximum abrasivity standard of 250 can be created in situ simply by including a treatment group of standard abrasive with 2.5x number of brushing strokes. RDA-PE is enabled in large part by the availability of easy-to-use and well-standardized modern profilometers, but its use in V8 brushing machines is enabled by the unique specific conditions described herein. RDA-PE permits the evaluation of dentifrice abrasivity to dentin without the requirement of irradiated teeth and infrastructure for handling them. In direct comparisons, the RDA-PE method provides dentifrice abrasivity assessments comparable to the gold industry standard RDA technique.

  8. Clinico-epidemiological profile of tobacco users attending a tobacco cessation clinic in a teaching hospital in Bangalore city

    OpenAIRE

    George D′Souza; Dorothy P Rekha; Priya Sreedaran; Srinivasan, K.; Mony, Prem K

    2012-01-01

    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 Ba...

  9. The effect of single-application fluoride treatment on simulated gastric erosion and erosion-abrasion of enamel in vitro.

    Science.gov (United States)

    Austin, Rupert S; Stenhagen, Kjersti Refsholt; Hove, Lene Hystad; Tveit, Anne Bjørg; Moazzez, Rebecca V; Bartlett, David W

    2014-01-01

    To compare single-application fluoride formulations on enamel erosion and erosion-abrasion in vitro. Enamel specimens were pretreated with either sodium, tin, titanium, or sodium/calcium fluoride and subjected to either an erosion model or an erosion-abrasion model, after which optical profilometry was used to measure enamel step height loss. For erosion, the titanium fluoride (P .05). For erosion-abrasion, the titanium fluoride increased enamel loss in comparison to control (P fluoride has differing effects on enamel loss from erosion and erosion-abrasion models.

  10. Emission factors and source apportionment for abrasion particles produced by road traffic

    Science.gov (United States)

    Bukowiecki, N.; Lienemann, P.; Figi, R.; Hill, M.; Richard, A.; Furger, M.; Rickers, K.; Cliff, S. S.; Baltensperger, U.; Gehrig, R.

    2009-04-01

    Particle emissions of road traffic are generally associated with fresh exhaust emissions only. However, recent studies identified a clear contribution of non-exhaust emissions to the PM10 load of the ambient air. These emissions consist of particles produced by abrasion from brakes, road wear, tire wear, as well as resuspension of deposited road dust. For many urban environments, quantitative information about the contributions of the individual abrasion processes is still scarce. For effective PM10 reduction scenarios it is of particular interest to know whether road wear, resuspension or fresh abrasion from vehicles is dominating the non-exhaust PM10 contribution. In Switzerland, the emissions of road traffic abrasion particles into the ambient air were characterized in the project APART (Abrasion Particles produced by Road Traffic). The project aimed at finding the contribution of the non-exhaust sources to total traffic-related PM10 and PM2.5 for different traffic conditions, by determining specific elemental fingerprint signatures for the various sources. This was achieved by hourly elemental mass concentration measurements in three size classes (2.5-10, 1-2.5 and 0.1-1 micrometers) with a rotating drum impactor (RDI) and subsequent synchrotron radiation X-ray fluorescence spectrometry (SR-XRF). The elemental fingerprint measurements were embedded into a large set of aerosol, gas phase, meteorological and traffic count measurements. To identify traffic related emissions, measurements were performed upwind and downwind of selected roads. For a better investigation of road wear, a road wear simulator was applied in additional experiments. This allows for the identification and quantification of the different source contributions by means of source-receptor modeling, and for the calculation of real-world emission factors for the individual abrasion sources. The preliminary analysis of hourly resolved trace element measurements in a street canyon in Zürich showed

  11. Computational Fluid Dynamic Simulation of Flow in Abrasive Water Jet Machining

    Science.gov (United States)

    Venugopal, S.; Sathish, S.; Jothi Prakash, V. M.; Gopalakrishnan, T.

    2017-03-01

    Abrasive water jet cutting is one of the most recently developed non-traditional manufacturing technologies. In this machining, the abrasives are mixed with suspended liquid to form semi liquid mixture. The general nature of flow through the machining, results in fleeting wear of the nozzle which decrease the cutting performance. The inlet pressure of the abrasive water suspension has main effect on the major destruction characteristics of the inner surface of the nozzle. The aim of the project is to analyze the effect of inlet pressure on wall shear and exit kinetic energy. The analysis could be carried out by changing the taper angle of the nozzle, so as to obtain optimized process parameters for minimum nozzle wear. The two phase flow analysis would be carried by using computational fluid dynamics tool CFX. It is also used to analyze the flow characteristics of abrasive water jet machining on the inner surface of the nozzle. The availability of optimized process parameters of abrasive water jet machining (AWJM) is limited to water and experimental test can be cost prohibitive. In this case, Computational fluid dynamics analysis would provide better results.

  12. Comparative analysis between hard- and soft-filament toothbrushes related to plaque removal and gingival abrasion.

    Science.gov (United States)

    Carvalho, Rosimary de Sousa; Rossi, Vanessa; Weidlich, Patrícia; Oppermann, Rui Vicente

    2007-01-01

    The aim of this split-mouth, examiner-blind study was to compare the dental plaque removal and incidence of gingival abrasion associated with the use of hard- and soft-filament toothbrushes. The test group consisted of 20 non-dental students, mean age 25 years. After a three-day period of plaque accumulation following the use of a disclosing solution, the Quigley-Hein Plaque Index was recorded, while the presence of gingival abrasion was measured from photographs. Pairs of quadrants 1-3 and 2-4 were allocated to supervised brushing with hard- or soft-filament toothbrushes for 30 seconds, limited to the buccal aspects of the teeth. Plaque levels and gingival abrasion were again assessed. Initial and final values of the plaque index and the mean number of abrasions were compared with the Friedman and Wilcoxon tests (p < or = 0.05). Plaque indices were reduced significantly from a baseline of 4.12 in both groups to 1.21 after the use of hard-filament toothbrushes, and to 1.67 after the use of soft-filament toothbrushes. The use of hard-filament toothbrushes resulted in a significantly higher mean number of lesions when compared to the soft-filament toothbrushes; 11.6 and 7.9, respectively (p = 0.018). Hard-filament toothbrushes remove more plaque than soft filament brushes, but also cause a higher number of gingival abrasions.

  13. Abrasive wear characteristics and mechanisms of Al2O3/PA1010 composite coatings

    Institute of Scientific and Technical Information of China (English)

    JIA Xian; LING Xiaomei

    2004-01-01

    The abrasive wear characteristics of Al2O3/PA1010 composite coatings on the surface of quenched and low-temperature temper steel 45 were tested on the mmplate abrasive wear testing machine and the same uncoated steel 45 was used as a reference material. Experimental results showed that the abrasive wear resistance of Al2O3//PAl010 composite coatings has a good linear relationship with the volume fraction of Al2O3 particles in Al2O3/PAl010 composite coatings, and the linear correlative coefficient is 0.979. Under the experimental conditions, the size of Al2O3 particles (40.5-161.0 μm) has little influence on the abrasive wear resistance of Al2O3/PA l010 composite coatings. By treating the surface of Al2O3 particles with a suitable bonding agent, the distribution of Al2O3 particles in matrix PAl010 is more homogeneous and the bonding state between Al2O3 particles and matrix PAl010 is better. Therefore, the ml2O3 particles in Al2O3/PA1010 composite coatings make the Al2O3/PAl010 composite coatings have better abrasive wear resistance than PA1010 coatings. The wear resistance of Al2O3/PA 1010 composite coatings is about 45% compared with that of steel 45.

  14. Abrasion of human enamel by brushing with a commercial dentifrice containing hydroxyapatite crystals in vitro.

    Science.gov (United States)

    Kodaka, T; Kobori, M; Hirayama, A; Abe, M

    1999-01-01

    Automatic toothbrushing with a commercial dentifrice containing hydroxyapatite (HAP) crystals was performed on the tangential polished surfaces of sound human enamel, mainly consisting of biological apatite similar to HAP, for 10 min in vitro. The X-ray diffraction peaks of HAP, brushite (DCPD), and monetite (DCP) crystals were detected from the dentifrice. After brushing, the enamel surfaces were observed with a scanning electron and a confocal scanning laser microscope. The brushing caused larger abrasive loss and more remarkable roughness of the enamel surfaces following the broad traces of brush bristles and the exposure of prism structures than brushing with a dentifrice containing only DCPD, which we previously reported. We claim that the fine granular-shaped HAP crystals of the dentifrice indicated as an active ingredient for preventing enamel caries possess stronger abrasivity of sound enamel than the DCPD and DCP as abrasives on account of their Mohs hardness values rather than sizes and shapes. The HAP crystals of dentifrices may not occlude the small defects of early caries enamel, but erode them more strongly as an abrasive than the other abrasives.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  16. Finishing of display glass for mobile electronics using 3M Trizact diamond tile abrasive pads

    Science.gov (United States)

    Zheng, Lianbin; Fletcher, Tim; Na, Tee Koon; Sventek, Bruce; Romero, Vince; Lugg, Paul S.; Kim, Don

    2010-10-01

    This paper will describe a new method being used during the finishing of glass displays for mobile electronics including mobile hand held devices and notebook computers. The new method consists of using 3M TrizactTM Diamond Tile Abrasive Pads. TrizactTM Diamond Tile is a structured fixed abrasive grinding technology developed by 3M Company. The TrizactTM Diamond Tile structured abrasive pad consists of an organic (polymeric binder) - inorganic (abrasive mineral, i.e., diamond) composite that is used with a water-based coolant. TrizactTM Diamond Tile technology can be applied in both double and single side grinding applications. A unique advantage of TrizactTM Diamond Tile technology is the combination of high stock removal and low sub-surface damage. Grinding results will be presented for both 9 micron and 20 micron grades of TrizactTM Diamond Tile abrasive pads used to finish several common display glasses including Corning GorillaTM glass and Soda Lime glass.

  17. Effect of carbonitride precipitates on the abrasive wear behaviour of hardfacing alloy

    Science.gov (United States)

    Yang, Ke; Yu, Shengfu; Li, Yingbin; Li, Chenglin

    2008-06-01

    Hardfacing alloy of martensitic stainless steel expect higher abradability to be achieved through the addition of nitrogen being provided by the fine scale precipitation of complex carbonitride particles. Niobium and titanium as the most effective carbonitride alloying elements were added in the Fe-Cr13-Mn-N hardfacing alloy to get carbonitride precipitates. Carbonitride was systematically studied by optical microscopy, scanning electronic microscopy and energy spectrum analysis. Abrasive wear resistance of hardfacing alloy in as-welded and heat-treated conditions was tested by using the belt abrasion test apparatus where the samples slide against the abrasive belt. It is found that carbonitride particles in the hardfacing alloy are complex of Cr, Ti and Nb distributing on the grain boundary or matrix of the hardfacing alloy with different number and size in as-welded and heat-treated conditions. A large number of carbonitrides can be precipitated with very fine size (nanoscale) after heat treatment. As a result, the homogeneous distribution of very fine carbonitride particles can significantly improve the grain-abrasion wear-resisting property of the hardfacing alloy, and the mass loss is plastic deformation with minimum depth of grooving by abrasive particles and fine delamination.

  18. The effect of heat treatment on the gouging abrasion resistance of alloy white cast irons

    Science.gov (United States)

    Are, I. R. S.; Arnold, B. K.

    1995-02-01

    A series of heat treatments was employed to vary the microstructure of four commercially important alloy white cast irons, the wear resistance of which was then assessed by the ASTM jaw-crusher gouging abrasion test. Compared with the as-cast condition, standard austenitizing treatments produced a substantial increase in hardness, a marked decrease in the retained aus-tenite content in the matrix, and, in general, a significant improvement in gouging abrasion resistance. The gouging abrasion resistance tended to decline with increasing austenitizing tem-perature, although the changes in hardness and retained austenite content varied, depending on alloy composition. Subcritical heat treatment at 500 ° following hardening reduced the retained austenite content to values less than 10 pct, and in three of the alloys it caused a significant fall in both hardness and gouging abrasion resistance. The net result of the heat treatments was the development of optimal gouging abrasion resistance at intermediate levels of retained aus-tenite. The differing responses of the alloys to both high-temperature austenitizing treatments and to subcritical heat treatments at 500 ° were related to the effects of the differing carbon and alloying-element concentrations on changes in the M s temperature and secondary carbide precipitation.

  19. Hybrid layer thickness and morphology: Influence of cavity preparation with air abrasion.

    Science.gov (United States)

    Barceleiro, Marcos Oliveira; de Mello, Jose Benedicto; Porto, Celso Luis de Angelis; Dias, Katia Regina Hostilio Cervantes; de Miranda, Mauro Sayao

    2011-01-01

    Dentinal surfaces prepared with air abrasion have considerably different characteristics from those prepared with conventional instruments. Different hybrid layer morphology and thickness occur, which can result in differences in the quality of restorations placed on dentinal surfaces prepared with a diamond bur compared to surfaces prepared using air abrasion. The objective of this study was to compare the hybrid layer thickness and morphology formed utilizing Scotchbond Multi-Purpose Plus (SBMP) on dentin prepared with a diamond bur in a high-speed handpiece and on dentin prepared using air abrasion. Flat dentin surfaces obtained from five human teeth were prepared using each method, then treated with the dentin adhesive system according to manufacturer's instructions. After a layer of composite was applied, specimens were sectioned, flattened, polished, and prepared for scanning electron microscopy. Ten different measurements of hybrid layer thickness were obtained along the bonded surface in each specimen. SBMP produced a 3.43 ± 0.75 µm hybrid layer in dentin prepared with diamond bur. This hybrid layer was regular and found consistently. In the air abrasion group, SBMP produced a 4.94 ± 1.28 µm hybrid layer, which was regular and found consistently. Statistical ANOVA (P = 0.05) indicated that there was a statistically significant difference between the groups. These data indicate that the air abrasion, within the parameters used in this study, provides a thick hybrid layer formation.

  20. Projectile Nose Mass Abrasion of High-Speed Penetration into Concrete

    Directory of Open Access Journals (Sweden)

    Haijun Wu

    2012-01-01

    Full Text Available Based on the dynamic spherical cavity expansion theory of concrete and the analysis of experimental data, a mass abrasion model of projectile considering the hardness of aggregates, the relative strength of target and projectile, and the initial impact velocity is constructed in this paper. Furthermore, the effect of mass abrasion on the penetration depth of projectile and the influence of hardness of aggregates and strength of projectile on penetration depth and mass loss are also analyzed. The results show that, for the ogive-nose projectile with the CRH of 3 and aspect ratio of 7 penetrating the concrete of 35 MPa, the “rigid-body penetration” model is available when the initial impact velocity is lower than 800 m/s. However, when the initial impact velocity is higher than 800 m/s, the “deforming/eroding body penetration” model should be adopted. Through theoretical analysis and numerical calculation, the results indicate that the initial impact velocity is the most important factor of mass abrasion. The hardness of aggregates and the strength of projectile are also significant factors. But relatively speaking, the sensitivity of strength of projectile to mass abrasion is higher, which indicates that the effect of projectile material on mass abrasion is more dramatic than the hardness of aggregates.

  1. Comparative evaluation of enamel abrasivity by toothbrush and velcro: An in vitro scanning electron microscope study

    Directory of Open Access Journals (Sweden)

    Saroj Kumar Ojha

    2015-01-01

    Full Text Available Context: Plaque control has been shown to be pivotal in maintaining the optimal periodontal health. Mechanical plaque control is the most popular option for establishing the optimal oral health. Toothbrushes have been the novel tool for mechanical cleansing. However, the abrasive potential of the toothbrushes on the enamel surface is an area in gray. Aims: The aim of this in vitro study is to evaluate the abrasivity of the toothbrush versus the velcro fasteners. Settings and Design: Forty extracted clinically healthy premolars were grouped in two groups. Group A comprising of teeth that were subjected to toothbrush bristles and group B to velcro fasteners (hook and loop. Materials and Methods: The mounted teeth of both the groups were subjected to abrasion test, and the tooth surfaces were observed for the possible abrasions from the oscillating strokes (toothbrush and frictional contacts (hook and loop velcro and examined under the scanning electron microscope. Results: Comparative assessment of both velcro (hook and loop and toothbrush bristles did not reveal any evidence of abrasion on the tooth specimens. Conclusions: Veclro fasteners are safe and qualitatively at par to the manual toothbrush for their efficacy and efficiency in teeth cleansing

  2. Understanding Characteristic of Abrasion of Refractory Lining Caused by Bath Oscillation in BOF Steelmaking

    Science.gov (United States)

    Li, Qiang; Li, Mingming; Kuang, S. B.; Zou, Zongshu

    2016-12-01

    This paper presents a numerical study of the refractory abrasion occurring widely inside basic oxygen furnace (BOF) steelmaking. The mechanism of refractory abrasion is examined numerically referring to the bath oscillation with regard to flows, turbulence and wall shear stress inside a BOF. The simulation results reveal that the refractory abrasion tends to occur on the wall region between the slag/atmosphere and slag/metal interfaces due to the oscillation of the bath in the blowing process, which generally promotes slag-line erosion. The decreased nozzle angle, and either increased lance height or operation pressure can lead to more serious refractory erosion that occurs more likely during the slag-making period in the operation of BOF.

  3. Computational Fluid Dynamics Analysis of Nozzle in Abrasive Water Jet Machining

    Science.gov (United States)

    Venugopal, S.; Chandresekaran, M.; Muthuraman, V.; Sathish, S.

    2017-03-01

    Abrasive water jet cutting is one of the most recently developed non-traditional manufacturing technologies. The general nature of flow through the machining, results in rapid wear of the nozzle which decrease the cutting performance. It is well known that the inlet pressure of the abrasive water suspension has main effect on the erosion characteristics of the inner surface of the nozzle. The objective of the project is to analyze the effect of inlet pressure on wall shear and exit kinetic energy. The analysis would be carried out by varying the inlet pressure of the nozzle, so as to obtain optimized process parameters for minimum nozzle wear. The two phase flow analysis would be carried by using computational fluid dynamics tool CFX. The availability of minimized process parameters such as of abrasive water jet machining (AWJM) is limited to water and experimental test can be cost prohibitive.

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

    Science.gov (United States)

    Bridges, N.T.; Calef, F.J.; 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.

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

    Science.gov (United States)

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

    2014-06-01

    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.

  6. Evaluation of subsurface damage in GaN substrate induced by mechanical polishing with diamond abrasives

    Energy Technology Data Exchange (ETDEWEB)

    Aida, Hideo, E-mail: h-aida@namiki.net [NJC Institute of Technology, Namiki Precision Jewel Co., Ltd., 3-8-22 Shinden, Adachi, Tokyo 123-8511 (Japan); KASTEC, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan); Takeda, Hidetoshi; Kim, Seong-Woo; Aota, Natsuko; Koyama, Koji [NJC Institute of Technology, Namiki Precision Jewel Co., Ltd., 3-8-22 Shinden, Adachi, Tokyo 123-8511 (Japan); Yamazaki, Tsutomu; Doi, Toshiro [KASTEC, Kyushu University, Kasuga-shi, Fukuoka 816-8580 (Japan)

    2014-02-15

    The relationship between the depth of the subsurface damage (SSD) and the size of the diamond abrasive used for mechanical polishing (MP) of GaN substrates was investigated in detail. GaN is categorized as a hard, brittle material, and material removal in MP proceeds principally to the fracture of GaN crystals. Atomic force microscopy and cathodoluminescence imaging revealed that the mechanical processing generated surface scratches and SSD. The SSD depth reduced as the diamond abrasive size reduced. A comparison of the relationship between the SSD depth and the diamond abrasive size used in the MP of GaN with the same relationship for typical brittle materials such as glass substrates suggests that the MP of GaN substrates proceeds via the same mechanism as glass.

  7. Structural transformations in wear resistance of iron- and cobalt-based amorphous alloys during abrasive wear

    Science.gov (United States)

    Korshunov, L. G.; Shabashov, V. A.; Chernenko, N. L.

    2010-04-01

    The wear resistance and structural changes in a number of amorphous alloys based on iron and cobalt and in high-carbon tool steels are studied during wear by a fixed abrasive (crondum, Carborundum) at room temperature and -196°C. The abrasive wear resistance of the amorphous alloys is shown to be 1.6-3.1 lower than that of the high-carbon tool steels having a similar hardness. The relatively low level of the abrasive wear resistance of the amorphous alloys is assumed to be caused by strain softening of their surface during wear. A nanocrystalline structure is found to form in local microvolumes in a thin deformed surface layer of the alloys.

  8. An Investigation on a Tin Fixed Abrasive Polishing Pad with Phyllotactic Pattern for Polishing Wafer

    Institute of Scientific and Technical Information of China (English)

    吕玉山; 刘电飞; 寇智慧

    2012-01-01

    In order to improve the polishing ability of polishing pads, a kind of polishing pad with the tin fixed abrasive blocks, which are arranged based on the phyllotaxis theory of biology, was designed and fabricated by the use of electroplating technology, and also its polishing ability for JGS-2 wafer was investigated by polishing experiments. The research resuits show that the phyllotactic parameters of the polishing pad influence the arrangement density of the tin fixed abrasive blocks, the polishing pad with phyllotactic pattern is feasibly fabricated by the use of electroplating technology, and the good polishing result can be obtained by using the polishing pad with pbyllotactic pattern to polish a wafer when the diameter D of the tin fixed abrasive block is between Φ. 3 mm and Φ1. 4 mm, and the phyllotactic coefficient k between 1.0 and 1.1, respectively.

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

    Science.gov (United States)

    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.

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

    Indian Academy of Sciences (India)

    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.

  11. A Review on Current Research and Development in Abrasive Waterjet Machining

    Directory of Open Access Journals (Sweden)

    M. M. Korat

    2014-01-01

    Full Text Available Abrasive waterjet machining (AWJM is an emerging machining technology option for hard material parts that are extremely difficult-to-machine by conventional machining processes. A narrow stream of high velocity water mixed with abrasive particles gives relatively inexpensive and environment friendly production with reasonably high material removal rate. Because of that abrasive waterjet machining has become one of the leading manufacturing technologies in a relatively short period of time. This paper reviews the research work carried out from the inception to the development of AWJM within the past decade. It reports on the AWJM research relating to improving performance measures, monitoring and control of process, optimizing the process variables. A wide range of AWJM industrial applications for different category of material are reported with variations. The paper also discusses the future trend of research work in the same area.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

  14. Sporadic late-onset nemaline myopathy: clinico-pathological characteristics and review of 76 cases.

    Science.gov (United States)

    Schnitzler, Lukas J; Schreckenbach, Tobias; Nadaj-Pakleza, Aleksandra; Stenzel, Werner; Rushing, Elisabeth J; Van Damme, Philip; Ferbert, Andreas; Petri, Susanne; Hartmann, Christian; Bornemann, Antje; Meisel, Andreas; Petersen, Jens A; Tousseyn, Thomas; Thal, Dietmar R; Reimann, Jens; De Jonghe, Peter; Martin, Jean-Jacques; Van den Bergh, Peter Y; Schulz, Jörg B; Weis, Joachim; Claeys, Kristl G

    2017-05-11

    Sporadic late-onset nemaline myopathy (SLONM) is a rare, late-onset muscle disorder, characterized by the presence of nemaline rods in muscle fibers. Phenotypic characterization in a large cohort and a comprehensive overview of SLONM are lacking. We studied the clinico-pathological features, treatment and outcome in a large cohort of 76 patients with SLONM, comprising 10 new patients and 66 cases derived from a literature meta-analysis (PubMed, 1966-2016), and compared these with 15 reported HIV-associated nemaline myopathy (HIV-NM) cases. In 6 SLONM patients, we performed a targeted next-generation sequencing (NGS) panel comprising 283 myopathy genes. SLONM patients had a mean age at onset of 52 years. The predominant phenotype consisted of weakness and atrophy of proximal upper limbs in 84%, of proximal lower limbs in 80% and both in 67%. Other common symptoms included axial weakness in 68%, as well as dyspnea in 55% and dysphagia in 47% of the patients. In 53% a monoclonal gammopathy of unknown significance (MGUS) was detected in serum. The mean percentage of muscle fibers containing rods was 28% (range 1-63%). In 2 cases ultrastructural analysis was necessary to detect the rods. The most successful treatment in SLONM patients (all with MGUS) was autologous peripheral blood stem cell therapy. A targeted NGS gene panel in 6 SLONM patients (without MGUS) did not reveal causative pathogenic variants. In a comparison of SLONM patients with and without MGUS, the former comprised significantly more males, had more rapid disease progression, and more vacuolar changes in muscle fibers. Interestingly, the muscle biopsy of 2 SLONM patients with MGUS revealed intranuclear rods, whereas this feature was not seen in any of the biopsies from patients without paraproteinemia. Compared to the overall SLONM cohort, significantly more HIV-NM patients were male, with a lower age at onset (mean 34 years). In addition, immunosuppression was more frequently applied with more

  15. Abrasion Testing of Candidate Outer Layer Fabrics for Lunar EVA Space Suits

    Science.gov (United States)

    Mitchell, Kathryn C.

    2010-01-01

    During the Apollo program, the space suit outer layer fabrics were badly abraded after just a few Extravehicular Activities (EVAs). For example, the Apollo 12 commander reported abrasive wear on the boots, which penetrated the outer layer fabric into the thermal protection layers after less than eight hours of surface operations. Current plans for the Constellation Space Suit Element require the space suits to support hundreds of hours of EVA on the Lunar surface, creating a challenge for space suit designers to utilize materials advances made over the last forty years and improve upon the space suit fabrics used in the Apollo program. A test methodology has been developed by the NASA Johnson Space Center Crew and Thermal Systems Division for establishing comparative abrasion wear characteristics between various candidate space suit outer layer fabrics. The abrasion test method incorporates a large rotary drum tumbler with rocks and loose lunar simulant material to induce abrasion in fabric test cylinder elements, representative of what might occur during long term planetary surface EVAs. Preliminary materials screening activities were conducted to determine the degree of wear on representative space suit outer layer materials and the corresponding dust permeation encountered between subsequent sub -layers of thermal protective materials when exposed to a simulated worst case eight hour EVA. The test method was used to provide a preliminary evaluation of four candidate outer layer fabrics for future planetary surface space suit applications. This Paper provides a review of previous abrasion studies on space suit fabrics, details the methodologies used for abrasion testing in this particular study, and shares the results and conclusions of the testing.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  17. [Evaluation of potential risks of abrasive water jet osteotomy in-vivo].

    Science.gov (United States)

    Kuhlmann, C; Pude, F; Bishup, C; Krömer, S; Kirsch, L; Andreae, A; Wacker, K; Schmolke, S

    2005-10-01

    Since the 80's the water jet scalpel is an established tool in some surgical fields. It is used in particular in visceral surgery for preparation of parenchymatous organs. By the addition of biocompatible abrasives, this technique is able to effectively machine hard biological tissues. Free defined cutting geometries can be realised in a non contact process. Therewith this method has crucial advantages compared to conventional osteotomy techniques and gives new impulses to the development in endoprosthetics and correction osteotomies of hollow bones. In the presented work the new developed abrasive water injection jet (AWIJ) was used the first time for in-vivo osteotomies. Aim of this study was the detection of potential thrombembolic effects and wash in effects of the cutting fluid. Hollow bones of the fore and hind leg of 20 house pigs were treated with the new cutting technique. Intraoperative documentation of relevant vital parameters was performed by a multi monitoring system. Thrombembolic effects during the osteotomy were detected by transthoracic Doppler ultrasonography and transesophagale echocardiography. The hollow bones were prepared in consideration of the vascularisation's protection especially in respect to the venous flow. Thrombembolic effects with temporary haemodynamic respectively respiratory consequences could be detected exclusively by using the so called "3-component jet", which consists of 90 vol % of air. The usage of an abrasive suspension enables the airfree dosing of dry soluable abrasives. Thrombembolic effects could not be monitored in this case. Intramedullary fluid in-wash effects as well as resulting electrolytic disorders could not be proven. For abrasive waterjet osteotomies with 3 component jet a relevant risk of thrombembolic effects could be shown. This knowledge has also to be considered for abdominal and neurosurgical applications in the future. Due to the usage of an abrasive suspension this risk can fully be avoided.

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

    OpenAIRE

    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...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  1. Methods for atomistic abrasion simulations of laterally periodic polycrystalline substrates with fractal surfaces

    Science.gov (United States)

    Eder, S. J.; Bianchi, D.; Cihak-Bayr, U.; Gkagkas, K.

    2017-03-01

    In this work we discuss a method to generate laterally periodic polycrystalline samples with fractal surfaces for use in molecular dynamics simulations of abrasion. We also describe a workflow that allows us to produce random lateral distributions of simple but realistically shaped hard abrasive particles with Gaussian size distribution and random particle orientations. We evaluate some on-the-fly analysis and visualization possibilities that may be applied during a molecular dynamics simulation to considerably reduce the post-processing effort. Finally, we elaborate on a parallelizable post-processing approach to evaluating and visualizing the surface topography, the grain structure and orientation, as well as the temperature distribution in large atomistic systems.

  2. Abrasive Wear Behavior of High Chromium Cast Iron and Hadfield Steel-- A Comparison

    Institute of Scientific and Technical Information of China (English)

    Mehdi Mazar Atabaki; Sajjad Jafari; Hassan Abdollah-pour

    2012-01-01

    Wear properties of two different crushers used for grinding raw materials of cement industry are compared using pin-on-disk wear test.The wear test was carried out with different loads on a pin.Abrasive wear behavior of two alloys was evaluated by comparing mass loss,wear resistance,microhardness and friction coefficient.The microstructure of the specimens was detected using optical microscope.The results showed that abrasive wear of high chromium cast iron is lower than that of Hadfield steel.Due to the presence of M7C3 carbides on the high chromium cast iron matrix,impact crushers exhibited higher friction coefficient

  3. Development and validation of an alternative disturbed skin model by mechanical abrasion to study drug penetration

    Directory of Open Access Journals (Sweden)

    P. Schlupp

    2014-01-01

    Skin permeation of the three substances was increased in tape-stripped and abraded skin compared to untreated skin due to the reduced barrier integrity. Enhancement of drug uptake was highest for the most hydrophilic substance, caffeine, followed by sorbic acid and lipophilic testosterone. No significant difference in drug uptake studies was observed between the new abrasion method with an aluminum-coated sponge and the tape-stripping method. The obtained results demonstrate that this abrasion method is an alternative way to achieve a disturbed skin barrier for drug and chemical uptake studies.

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

    OpenAIRE

    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...

  5. Water jet and abrasive water jet cutting of unidirectional graphite/epoxy composite

    Science.gov (United States)

    Ramulu, M.; Arola, D.

    1993-06-01

    Unidirectional graphite/epoxy composite material has been machined by water jet and abrasive water jet cutting processes. Topography and morphology of the machined surfaces were evaluated with surface profilometry and scanning electron microscopy. The surface characteristics in terms of roughness and the micromechanisms of material removal for both processes were analyzed and compared. Abrasive water jet surface characteristics of graphite/epoxy were found to be significantly different from those of the water jet cutting process and micromechanical behavior of material removal was strongly dependent on the fiber orientation.

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

    Directory of Open Access Journals (Sweden)

    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.

  7. Impact of Abrasion on Mass Loss and Surface Appearance of Woven Fabrics Made with Injected Slub Yarn in Weft

    Science.gov (United States)

    Ray, Nemai Chandra; Mukhopadhyay, Arunangshu; Midha, Vinay Kumar

    2016-10-01

    Fancy yarn fabrics are susceptible to abrasive damage during washing and usage but the extent of damage varies with construction and type of fabric. In the present study, effect of different slub parameters viz. slub length, slub thickness and slub frequency of single base injected slub yarn on abrasive damage of woven fabrics has been studied when injected slub yarns are used in weft only. Abrasive damage has been assessed by two ways using loss in fabric mass and deterioration in fabric appearance due to abrasion. These two techniques provide entirely different effect of injected slub yarn parameters on abrasive damage of woven fabric. Fabric abrasion damage in terms of mass loss is not affected by slub thickness and damage is least when both slub length and slub frequency are at central/medium level. Under visual assessment it is observed that all the slub parameters have significant influence on abrasive damage of woven fabric. It is possible to have lower damage in surface appearance in spite of higher mass loss of fabric due to abrasion.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  10. On the abrasion of heat-treated 2.8C21Cr1Mo white cast iron

    Energy Technology Data Exchange (ETDEWEB)

    Al-Rubaie, Kassim S.; Preti, Orlando [Centro Universitario SOCIESC, Joinville (Brazil). Engenharia Mecanica; Pohl, Michael [Bochum Univ. (Germany). Inst. fuer Werkstoffe

    2016-09-15

    The abrasion behaviour of heat-treated 2.8C21Cr1Mo cast iron was studied. The specimens were destabilised at two temperatures, 980 and 1050 C, for 4 h, air hardened, and then tempered at five temperatures, 220, 320, 400, 500, and 620 C, for 2 h followed by air cooling. Using a pin-on-plate abrasion apparatus, the specimens were abraded on four types of bonded abrasives (silicon carbide, corundum, flint, and glass). The effect of work hardening on the abrasion resistance was investigated. It was found that the increase in alloy hardness produced by heat treatment had little effect on the abrasion resistance against silicon carbide or corundum; the inverse was true against flint or glass. The as-hardened structure containing 40% retained austenite gave the best abrasion resistance, whereas the hardened and tempered at 620 C showed the worst. Both bulk hardness and matrix hardness before wear correlated poorly with the abrasion resistance. Therefore, a general model ''equivalent hardness'' was developed, in which the hardness of the abraded matrix was considered. With this model, the abrasion behaviour can be clearly analysed.

  11. NK cells are necessary for recovery of corneal CD11c+ dendritic cells after epithelial abrasion injury

    Science.gov (United States)

    Mechanisms controlling CD11c(+) MHCII(+) DCs during corneal epithelial wound healing were investigated in a murine model of corneal abrasion. Selective depletion of NKp46(+) CD3- NK cells that normally migrate into the cornea after epithelial abrasion resulted in >85% reduction of the epithelial CD1...

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

    Directory of Open Access Journals (Sweden)

    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.

  13. 'Top of the basilar' syndrome. Clinico-radiological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Sato, Masaharu; Kuroda, Ryotaro; Nakatani, Jiro; Watanabe, Masaru; Akai, Fumiharu; Ioku, Masahiko

    1988-06-01

    Seventeen patients (age 23 - 81) having the ''top of the basilar'' syndrome were the subjects of this study. They were evaluated clinico-radiologically. The diagnosis of this syndrome was made by computerized tomography. The infarcted lesions of each patient were widely distributed in many areas among the thalamus, midbrain, pons, cerebellum, and occipital lobe. Both the thalami were involved in 8 patients. When the thalamus was involved bilaterally, the low density areas of both the thalami were demonstrated to be almost the same in size and symmetric in localization by computerized tomography, showing a characteristic pattern. Further, magnetic resonance imaging could reveal small lesions in the brain stem minutely. Angiography revealed that stenosis or occlusion was within the circle of 2 cm in diameter surrounding the five-forked road of the top of the basilar artery in 84.6 %. Recanalization of the occluded artery occurred in 61.5 %, which suggests that the embolism plays an important role in appearance of this syndrome. In spite of frequent recanalization hemorrhagic infarction never occurred. The prognosis was very poor.

  14. [Necrotic myelopathies and neoplastic pathologie. Three clinico-pathological cases (author's transl)].

    Science.gov (United States)

    Gray, F; Hauw, J J; Escourolle, R; Castaigne, P

    1980-01-01

    Three clinico-pathological cases of necrotic myelopathies with a distant malignancy are presented. Two cases had a lymphosarcoma and one case a prostatic carcinoma. They were compared to 13 well studied other cases collected in the literature. These myelopathies were related to solid visceral tumours in 8 cases and to lymphomas in 5 cases. The disease could be individualized on clinical grounds (flaccid paraplegia with bladder and bowell incontinence and sensory loss without clear-cut upper boundary developing over a few weeks with normal CSF and fast impairement of general condition), and, on pathological features. It is characterized by one or several spinal cord necrosis areas, often asymetrical, involving mostly white matter, without any vascular topography. Axons are involved as well as myelin sheats. There is mild inflammation and no specific vascular alteration. There is no metastases in the cord, meninges, vertebral column or nerve root. No vascular occlusion is found. The mechanism of the disease is unknown. The frequent occurence of lymphomas could suggest the presence of immunopathological factors.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. Efficacy of crystallization test for screening of oral squamous cell carcinoma with clinico-pathological correlation

    Directory of Open Access Journals (Sweden)

    Sachin C Sarode

    2013-01-01

    Full Text Available Aim: To determine the efficacy of crystallization test for screening oral squamous cell carcinoma (OSCC with clinico-pathologic correlation. Materials and Methods: Fifty patients of OSCC and 30 healthy individuals were selected. One drop of blood was collected into 1 cc of doubled distilled water at room temperature to give a final dilution of 6% hemolyzed blood. 0.1 to 0.2 cc of blood sample was then subjected to crystallization test using 10% cupric chloride solution. Results: In healthy control group, the typical pattern was an eccentrically placed center of gravity with needles arranged in radiating fashion, while in OSCC group, there was ′transverse form′ (TF formation. The sensitivity and specificity of this test was found to be 96% and 96.66%, respectively. The positive and negative predictive values were found to be 97.96% and 98.55%, respectively. The mean TF frequency was found to be increasing from grade I (3.20 ± 1.5% to grade II (653 ± 2.23% and difference was statistically significant (P = 0.0001. However, there was no correlation between mean TF frequency and TNM stages of OSCC. Conclusion: Crystallization test is a simple, reliable, economical, less time-consuming, and less invasive screening procedure, which can be used for early detection of OSCC.

  17. Tegmental-type primary pontine hemorrhage with mesencephalic extension. Clinico-CT-anatomic correlations

    Energy Technology Data Exchange (ETDEWEB)

    Goto, Noboru; Ishikawa, Hiroshi; Kaneko, Mitsuo; Tanaka, Keisei

    1983-06-01

    In nine autopsy cases of tegmental-type primary pontine hemorrhage, two cases with a mesencephalic extension which was not accurately diagnosed symptomatologically, but which was clearly detected on CT films, were found. Correlative clinico-CT-anatomic reports on this kind of pontine hemorrhage have not been included in the literature. The two patients were both females, 73 and 53 years old. Both were hypertensive and under medical care. They showed disturbances of consciousness and respiration, pin-point pupils, fixed eyes in the midposition, right hemiplegia, right extensor plantar response, etc., but both responded well to painful stimuli on the left half of the body. CT examinations detected a continuous high-density area in the left-sided tegmentum of the pons and midbrain. They died 9 and 21 days later respectively. With the help of an electronic image analyser, a great volume of hematoma was measured in the postmortem brainstem in these cases (17 ml and 14 ml). Precise analyses of the correlations among clinical symptomatology, CT, and anatomical findings, and histological examinations were carried out in an attempt to find the pathogenesis of this disease. In the diagnosis of tegmental-type primary pontine hemorrhage, attention should be paid to a possible mesencephalic involvement as one of the modes of hematoma extension, although it may be rather rare.

  18. Odontogenic myxoma: clinico-pathological, immunohistochemical and ultrastructural findings of a multicentric series.

    Science.gov (United States)

    Martínez-Mata, Guillermo; Mosqueda-Taylor, Adalberto; Carlos-Bregni, Roman; de Almeida, Oslei Paes; Contreras-Vidaurre, Elisa; Vargas, Pablo Agustin; Cano-Valdéz, Ana María; Domínguez-Malagón, Hugo

    2008-06-01

    The aim of this study was to analyze the clinico-pathological and immunohistochemical features of 62 cases of odontogenic myxoma (OM) diagnosed in three Oral Pathology Diagnostic Services in Latin America, as well as to describe the ultrastructural features of three of these cases. OM showed a wide age range (9-71 years), with a mean of 27.97 yr (SD: 11.01) and a male to female ratio of 1:2.2. Mandible was affected in 37 cases (59.6%) and maxilla in 25 (40.4%), with 61.3% located in the posterior region. Thirty-nine cases (62.9%) were multilocular and 23 (37.1%) unilocular. Size ranged from 1 to 13 cm, (mean: 5.2 cm). Thirty-seven multilocular (54.8%) and 6 unilocular lesions (26%) were larger than 4 cm (pNSE and CD68, and showed a low index of expression of Bcl2 and ki-67 proteins (products. However, further investigations are needed to better understand the participation of these elements in this particular neoplasm.

  19. Progressive anterior operculum syndrome due to FTLD-TDP: a clinico-pathological investigation.

    Science.gov (United States)

    Otsuki, Mika; Nakagawa, Yoshitsugu; Mori, Fumiaki; Tobioka, Hirotoshi; Yoshida, Hideaki; Tatezawa, Yoshiharu; Tanigawa, Toshio; Takahashi, Ikuko; Yabe, Ichiro; Sasaki, Hidenao; Wakabayashi, Koichi

    2010-07-01

    Pathological investigation of progressive anterior operculum syndrome has rarely been reported. We describe clinico-pathological findings in a patient with progressive anterior operculum syndrome. A 74-year-old right-handed man had noticed speech and swallowing difficulties 1 year previously. Neurological examinations showed no abnormality other than a slight limitation of upward gaze and slow tongue movement without fibrillation. We investigated the patient using neuroimaging and neuropsychological examinations and observed him for 2 years until his death, at which point we obtained pathological findings. The patient's facial and masseteric muscles seemed hypotonic with drooling, but he could laugh and yawn normally, showing automatic voluntary dissociation. Palatal and pharyngeal reflexes were normal. Magnetic resonance imaging showed cortical atrophy in the temporal lobes bilaterally. (123)IMP single photon emission computed tomography and positron emission tomography showed decreased blood flow and activity in the frontotemporal lobes, predominantly on the left side. Neuropsychological examinations showed no aphasia, dementia or other neuropsychological abnormality. Intubation fiberscopy, laryngoscopy and video fluorography showed no abnormality. After 6 months his anarthria and dysphagia became aggravated. He died of aspiration pneumonia 2 years after onset. Postmortem examination revealed neuronal degeneration with TDP-43-positive inclusions in the frontal, temporal and insular cortices, consistent with frontotemporal lobar degeneration with TDP inclusions (FTLD-TDP). However, neuronal loss with gliosis was more prominent in the inferior part of the motor cortices, bilaterally. Progressive anterior operculum syndrome could be classified as a variant of FTLD-TDP.

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

    Science.gov (United States)

    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.

  1. Clinico-epidemiological and socio-behavioral study of people living with HIV/AIDS

    Directory of Open Access Journals (Sweden)

    Khan M

    2010-01-01

    Full Text Available Although India is in the grip of HIV/AIDS epidemic, not much information is available on clinico-epidemiological and socio-behavioral aspects of people living with HIV/AIDS (PLWHA. This study analyzed these features using standard methodologies in 82 HIV sero-positives, AIDS patients attending ART clinic of three major government hospitals of Delhi. Majority of the patients (73% were found to be young (<40 years and married (79%. As high as 91.5% came from low socio-economic class and more than 95% acquired HIV transmission through heterosexual routes. A large proportion (63% of these patients reported an extremely high level of anxiety, moderate level of stress and a borderline level of clinical depression. While most of the patients (72% were well-adjusted with the ART, the rest of the patients reported difference in making adjustment with the treatment schedules. The study suggests that counseling and supportive therapy could play a pivotal role in controlling anxiety, stress, depression and rehabilitating people with HIV/AIDS.

  2. Trifurcation of superficial brachial artery: a rare case with its clinico-embryological implications.

    Science.gov (United States)

    Gupta, N; Anshu, A; Dada, R

    2014-01-01

    Literatures on vasculature of upper limbs are crammed with reports of distinctly deviant version of normally prevalent vessels having modified origins, altered branching and odd courses. A unique anatomical variation in vascular pattern was observed during routine dissection of right upper limb in gross anatomy laboratory, AIIMS, New Delhi, India. The brachial artery was placed superficial to median nerve in the arm and therefore it was called superficial brachial artery. In the cubital fossa, 2.8 cm distal to intercondylar line of elbow joint, this superficial brachial artery terminated by trifurcation into radial, common interosseous and ulnar branches. Strikingly the ulnar branch, after its origin ran superficially over the median nerve and epitrochlear superficial flexor group of muscles of forearm in succession for the initial third of its course in the forearm, consequently it was addressed as superficial ulnar artery. The existence of superficial brachial artery in place of normal brachial artery, its termination by trifurcation into radial, common interosseous and superficial ulnar arteries with remarkably different courses, leads to confusing disposition of structures in the arm, cubital fossa and in the forearm and collectively makes this myriad of anatomical variations even rarer. The clinico-embryological revelations for combination of these unconventional observations, apprises and guides the specialized medical personnel attempting blind and invasive procedures in brachium and ante-brachium. This case report depicts the anatomical perspective and clinical implications on confronting a rare variant vasculature architecture pattern of upper limb.

  3. Clinico-pathological characteristics of different types of immunodeficiency-associated smooth muscle tumours.

    Science.gov (United States)

    Hussein, Kais; Rath, Berenice; Ludewig, Britta; Kreipe, Hans; Jonigk, Danny

    2014-09-01

    Rare Epstein-Barr virus (EBV)+ smooth muscle tumours (SMT) manifest typically under immunosuppression. Three major subtypes are known: human immunodeficiency virus-associated (HIV-SMT), after transplantation (PTSMT) or associated with congenital immunodeficiency syndromes (CI-SMT). So far, there are no analyses which compare the clinico-pathological characteristics of all three subtypes. Case reports and case series on these three tumour types were collected (1990-2012). Meta-data analysis was performed for identification of similarities and differences. A total of 73 HIV-SMT, 66 PTSMT and 9 CI-SMT were evaluated. There was a slight female predominance (55-67%). Children were affected nearly equally in HIV-SMT (33%) and PTSMT (35%), while all CI-SMT occurred in children. HIV-SMT manifested preferentially in the central nervous system, gut/liver, skin, lungs/larynx/pharynx and adrenal glands. PTSMT were predominantly found in the liver, lungs/larynx/pharynx, gut/spleen and brain. CI-SMT were often found in lungs/larynx, brain, liver, adrenal glands and spleen. Antecedent EBV+ lymphoproliferations manifested more often in PTSMT. In all three tumour subtypes, survival analyses did not show any significant differences regarding surgical therapeutic approaches, the occurrence of multiple tumours, tumour size or sarcoma-like histological features. HIV-SMT had the poorest overall survival, which might be attributed to HIV-associated infectious complications.

  4. Viral aetiology and clinico-epidemiological features of acute encephalitis syndrome in eastern India.

    Science.gov (United States)

    Rathore, S K; Dwibedi, B; Kar, S K; Dixit, S; Sabat, J; Panda, M

    2014-12-01

    This study reports clinico-epidemiological features and viral agents causing acute encephalitis syndrome (AES) in the eastern Indian region through hospital-based case enrolment during April 2011 to July 2012. Blood and CSF samples of 526 AES cases were investigated by serology and/or PCR. Viral aetiology was identified in 91 (17·2%) cases. Herpes simplex virus (HSV; types I or II) was most common (16·1%), followed by measles (2·6%), Japanese encephalitis virus (1·5%), dengue virus (0·57%), varicella zoster virus (0·38%) and enteroviruses (0·19%). Rash, paresis and cranial nerve palsies were significantly higher (P Case-fatality rates were 10·9% and 6·2% in AES cases with and without viral aetiology, respectively. Simultaneous infection of HSV I and measles was observed in seven cases. This report provides the first evidence on viral aetiology of AES viruses from eastern India showing dominance of HSV that will be useful in informing the public health system.

  5. An analysis of clinico-pathologic features of intraductal papillary mucinous neoplasm of the pancreas

    Institute of Scientific and Technical Information of China (English)

    LOU Wenhui; JIN Dayong; WANG Dansong; XU Xuefeng; KUANG Tiantao; QIN Xinyu

    2007-01-01

    The natural history and clinical manifestation of resected intraductal papillary mucinous neoplasm(IPMN)of the pancreas were elucidated,and based on this,a retrospective pancreatic database was reviewed to identify patients with IPMN who were surgically managed in our department from 1999 to June 2006.Pathologic rereview of each case was performed,and the clinico-pathologic features were examined.Student's T test and X2 analysis were used to identify factors associated with malignancy.Fifty-one patients were identified.There were 33 males and 18 females.One patient's pancreas was unresectable,two patients underwent a total pancreatectomy,42 patients had a pancreatecoduodenectomy and five patients had distal pancreatectomy.Main-duct type carcinoma was identified in 24 patients;branch-duct type in 15 patients,and mixed type in 12 patients.Invasive carcinoma was present in 35 patients.Weight loss and iaundice occurred more commonly in the invasive group.The average serum CA19-9 level was significantly higher in the invasive group(1542μ vs 94.5μ).The average diameter of the pancreatic duct was also wider in the invasive group (8.7 mm vs 4.3 mm).Significant predictors of malignant IPMNS included weight loss,iaundice,a high level of serum CA19-9.a large pancreatic duct and main-duct type carcinoma.

  6. Clinico-epidemiological study of near-hanging cases - An investigation from Nepal.

    Science.gov (United States)

    Atreya, Alok; Kanchan, Tanuj

    2015-07-01

    Hanging is one of the commonest methods of suicide. Epidemiological data of near-hanging patients from Nepal is limited. The present research from Nepal attempts to review the clinico-epidemiological profile of near-hanging patients. A retrospective review of case records was done for the near hanging patients admitted to a tertiary care teaching hospital in Nepal, between August 2012 and August 2014. Details regarding socio-demographic profile, circumstances of hanging, clinical details, and outcome etc. were obtained and examined. During the study period, 10 near hanging patients were admitted to the hospital. The majority of the patients were below 30 years. Mean age of the study group was 28.8 years. The GCS on arrival ranged between 5/15 and 15/15 with the mean GCS being 9.5/15. Hypoxic encephalopathy and cerebral edema were the only noted complications. None of the patient had a cervical spinal injury. All the patients survived the near hanging episode. The mean ICU and hospital stay were 3.9 days and 6.2 days respectively. Prompt resuscitation, active interventions and intensive care support favors a good prognosis. Psychiatric evaluation and support to the patients and their relatives is the key to preventing such attempts in future.

  7. Bilirubin-Induced Neurological Dysfunction: A Clinico-Radiological-Neurophysiological Correlation in 30 Consecutive Children.

    Science.gov (United States)

    van Toorn, Ronald; Brink, Philip; Smith, Johan; Ackermann, Christelle; Solomons, Regan

    2016-12-01

    The clinical expression of bilirubin-induced neurological dysfunction varies according to severity and location of the disease. Definitions have been proposed to describe different bilirubin-induced neurological dysfunction subtypes. Our objective was to describe the severity and clinico-radiological-neurophysiological correlation in 30 consecutive children with bilirubin-induced neurological dysfunction seen over a period of 5 years. Thirty children exposed to acute neonatal bilirubin encephalopathy were included in the study. The mean peak total serum bilirubin level was 625 μmol/L (range 480-900 μmol/L). Acoustic brainstem responses were abnormal in 73% (n = 22). Pallidal hyperintensity was observed on magnetic resonance imaging in 20 children. Peak total serum bilirubin levels correlated with motor severity (P = .03). Children with severe motor impairment were likely to manifest severe auditory neuropathy (P < .01). We found that in a resource-constrained setting, classical kernicterus was the most common bilirubin-induced neurological dysfunction subtype, and the majority of children had abnormal acoustic brainstem responses and magnetic resonance imaging. © The Author(s) 2016.

  8. Grey and White Matter Clinico-Anatomical Correlates of Disinhibition in Neurodegenerative Disease

    Science.gov (United States)

    Santillo, Alexander Frizell; Lundblad, Karl; Nilsson, Markus; Landqvist Waldö, Maria; van Westen, Danielle; Lätt, Jimmy; Blennow Nordström, Erik; Vestberg, Susanna; Lindberg, Olof; Nilsson, Christer

    2016-01-01

    Disinhibition is an important symptom in neurodegenerative diseases. However, the clinico-anatomical underpinnings remain controversial. We explored the anatomical correlates of disinhibition in neurodegenerative disease using the perspective of grey and white matter imaging. Disinhibition was assessed with a neuropsychological test and a caregiver information-based clinical rating scale in 21 patients with prefrontal syndromes due to behavioural variant frontotemporal dementia (n = 12) or progressive supranuclear palsy (n = 9), and healthy controls (n = 25). Cortical thickness was assessed using the Freesurfer software on 3T MRI data. The integrity of selected white matter tracts was determined by the fractional anisotropy (FA) from Diffusion Tensor Imaging. Disinhibition correlated with the cortical thickness of the right parahippocampal gyrus, right orbitofrontal cortex and right insula and the FA of the right uncinate fasciculus and right anterior cingulum. Notably, no relationship was seen with the thickness of ventromedial prefrontal cortex. Our results support an associative model of inhibitory control, distributed in a medial temporal lobe-insular-orbitofrontal network, connected by the intercommunicating white matter tracts. This reconciles some of the divergences among previous studies, but also questions the current conceptualisation of the “prefrontal” syndrome and the central role attributed to the ventromedial prefrontal cortex in inhibitory control. PMID:27723823

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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

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

    Science.gov (United States)

    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 dentifrice can increase the incidence of abrasion, and should be used with caution by individuals who are at risk of developing gingival recession.

  12. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  13. Estudo clinico e eletromiografico dos musculos masseter e parte anterior do temporal de individuos com alterações funcionais do sistema estomatognatico tratados com aparelhos oclusal

    OpenAIRE

    Aladim Gomes Lameira

    1991-01-01

    Resumo: Foram examinados e tratados, treze pacientes todos do sexo feminino, com idade variável entre 14 e 43 anos, apresentando sinais e sintomas de alterações funcionais do sistema estomatognático. Foram realizadas avaliações eletromiográficas antes, com 60 e 120 dias de tratamento com férrulas oclusais duplas com puas, na posição postural ou de repouso e no fechamento sem esforço, fechamento com esforço e na mordida Incisiva. Os resultados eletromiográficos, foram comparados com a evoluçã...

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

    OpenAIRE

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

    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...

  15. Study of the indirect calibration of clinical air kerma-area meters; Estudo da calibracao indireta de medidores clinicos do produto kerma-area

    Energy Technology Data Exchange (ETDEWEB)

    Almeida Junior, Jose N. [Pontificia Univ. Catolica de Sao Paulo (PUC/SP), SP (Brazil). Curso de Fisica Medica; Silva, Marcia C. [Hospital Israelita Albert Einstein (HIAE), Sao Paulo, SP (Brazil); Terini, Ricardo A., E-mail: rterini@pucsp.b [Pontificia Univ. Catolica de Sao Paulo (DF/PUC/SP), SP (Brazil). Dept. de Fisica; Herdade, Silvio B. [Universidade de Sao Paulo (IEE/USP), SP (Brazil). Inst. de Eletrotecnica e Energia. Secao Tecnica de Desenvolvimento Tecnologico em Saude Marco A.G. Pereira

    2011-07-01

    Kerma-area product (P{sub KA}) is a quantity which is independent of the distance to the X-ray tube focal spot and that can be used to assess the effective dose in patients. Clinical P{sub KA} meters are usually calibrated on-site by measuring the air kerma with an ion chamber and evaluating the irradiated area by means of a radiographic image. This work presents a preliminary metrological evaluation of the calibration of a device marketed recently (PDC, Patient Dose Calibrator, Radcal), designed for calibrating clinical P{sub KA} meters. Results are also shown of applying the PDC to the cross calibration of a clinical P{sub KA} meter from a radiology equipment. Results confirm a lower energy dependence of the PDC relative to the tested clinical meter. (author)

  16. Comparative study among calibration methods of clinical applicators of beta radiation; Estudo comparativo entre metodos de calibracao de aplicadores clinicos de radiacao beta

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, Patricia de Lara

    2009-07-01

    {sup 90}Sr+{sup 90}Y clinical applicators are instruments used in brachytherapy procedures and they have to be periodically calibrated, according to international standards and recommendations. In this work, four calibration methods of dermatological and ophthalmic applicators were studied, comparing the results with those given by the calibration certificates of the manufacturers. The methods included the use of the standard applicator of the Calibration Laboratory (LCI), calibrated by the National Institute of Standards and Technology; an Amersham applicator (LCI) as reference; a mini-extrapolation chamber developed at LCI as an absolute standard; and thermoluminescent dosimetry. The mini-extrapolation chamber and a PTW commercial extrapolation chamber were studied in relation to their performance through quality control tests of their response, as leakage current, repeatability and reproducibility. The distribution of the depth dose in water, that presents high importance in dosimetry of clinical applicators, was determined using the mini extrapolation chamber and the thermoluminescent dosimeters. The results obtained were considered satisfactory for the both cases, and comparable to the data of the IAEA (2002) standard. Furthermore, a dosimetry postal kit was developed for the calibration of clinical applicators using the thermoluminescent technique, to be sent to clinics and hospitals, without the need of the transport of the sources to IPEN for calibration. (author)

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

    Science.gov (United States)

    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.

  18. Abrasive wear behavior of heat-treated ABC-silicon carbide

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao Feng; Lee, Gun Y.; Chen, Da; Ritchie, Robert O.; De Jonghe, Lutgard C.

    2002-06-17

    Hot-pressed silicon carbide, containing aluminum, boron, and carbon additives (ABC-SiC), was subjected to three-body and two-body wear testing using diamond abrasives over a range of sizes. In general, the wear resistance of ABC-SiC, with suitable heat treatment, was superior to that of commercial SiC.

  19. An in vitro evaluation of selective demineralised enamel removal using bio-active glass air abrasion.

    Science.gov (United States)

    Banerjee, Avijit; Pabari, Hiten; Paolinelis, George; Thompson, Ian D; Watson, Timothy F

    2011-12-01

    Unnecessary over-preparation of carious enamel often occurs clinically during operative caries management. The working hypothesis to be investigated in this study is the potential for bio-active glass air abrasion to remove selectively only demineralised enamel in artificial enamel lesions when compared to equivalent alumina air abrasion, so potentially minimising cavity over-preparation. Bisected artificial, paired smooth surface enamel lesions on ethics-approved, extracted sound human molars were created and subsequently air abraded with 27 μm alumina (n = 19) and bio-active glass (n = 19). The difference between pre-operative lesion boundary and post-operative cavity margin was calculated following optical confocal fluorescent assessment of the lesion boundary. Data indicated mean% over-preparation (sound enamel removal) of 176% with alumina and 15.2% for bio-active glass (p = 0.005). Bio-active glass abrasion removed completely the demineralised enamel from artificial lesions with clinically insignificant over-preparation of sound tissue, indicating technique selectivity towards grossly demineralised enamel. Alumina air abrasion resulted in substantial enamel removal in both sound and demineralised tissues indicating the operator selectivity required to use the techniques effectively in clinical practice.

  20. Chemical Abrasion Applied to LA-ICP-MS U–Pb Zircon Geochronology

    Directory of Open Access Journals (Sweden)

    Quentin G. Crowley

    2014-06-01

    Full Text Available Zircon (ZrSiO4 is the most commonly used mineral in U–Pb geochronology. Although it has proven to be a robust chronometer, it can suffer from Pb-loss or elevated common Pb, both of which impede precision and accuracy of age determinations. Chemical abrasion of zircon involves thermal annealing followed by relatively low temperature partial dissolution in HF acid. It was specifically developed to minimize or eliminate the effects of Pb-loss prior to analysis using Thermal Ionization Mass Spectrometry (TIMS. Here we test the application of chemical abrasion to Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS by analyzing zircons from both untreated and chemically abraded samples. Rates of ablation for high alpha-dose non-treated zircons are up to 25% faster than chemically abraded equivalents. Ablation of 91500 zircon reference material demonstrates a ca. 3% greater down-hole fractionation of 206Pb/238U for non-treated zircons. These disparities necessitate using chemical abrasion for both primary reference material and unknowns to avoid applying an incorrect laser induced fractionation correction. All treated samples display a marked increase in the degree of concordance and/or lowering of common Pb, thereby illustrating the effectiveness of chemical abrasion to LA-ICP-MS U–Pb zircon geochronology.

  1. Propelled abrasive grit applications for weed management in transitional corn grain production systems

    Science.gov (United States)

    Weed control is challenging to farmers who are transitioning from production systems that use synthetic herbicides to organic systems. A two-year field study examined weed control efficacy and corn grain yield of air-propelled corncob grit abrasion for in-row weed control. Grits were applied based o...

  2. Abrasive wear based predictive maintenance for systems operating in sandy conditions

    NARCIS (Netherlands)

    Woldman, M.; Tinga, T.; Heide, E. van der; Masen, M.A.

    2015-01-01

    Machines operating in sandy environments are damaged by the abrasive action of sand particles that enter the machine and become entrapped between components and contacting surfaces. In the case of the military services the combination of a sandy environment and the wide range of tasks to be fulfille

  3. Spent coffee grounds as air-propelled abrasive grit for weed control

    Science.gov (United States)

    Spent coffee grounds (SCG) represent a significant food waste residue. Value-added uses for this material would be beneficial. Gritty agricultural residues, such as corncob grit, can be employed as abrasive air-propelled agents for organically-compatible postemergence shredding of weed seedlings sel...

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Abrasion Behavior of High Manganese Steel under Low Impact Energy and Corrosive Conditions

    Directory of Open Access Journals (Sweden)

    Du Xiaodong

    2009-01-01

    Full Text Available The abrasion behavior of high manganese steel is investigated under three levels of impact energy in acid-ironstone slurry. The wear test was carried out by an MLDF-10 tester with impact energy of 0.7 J, 1.2 J, and 1.7 J. The impact abrasion property of high manganese steel in corrosive condition was compared according to the wear mass loss curves. The wear mechanism was analysed by the SEM analysis of the worn surface and the optical metallographic analysis of the vertical section to the wear surface. The results show that the impact energy has a great effect on the impact corrosion and abrasion properties of it. Its abrasion mechanism in corrosive condition is mainly microplough and breakage of plastic deformed ridges and wedges under the impact energy of 0.7 J. It is mainly the spelling of plastic deformed ridges and wedges under 1.2 J and the spalling of the work-hardening layer under 1.7 J after a long time testing.

  6. Platelet response to corneal abrasion is necessary for acute inflammation and efficient re-epithelialization

    Science.gov (United States)

    Purpose: Adhesion molecules play a critical role in leukocyte emigration to wound sites, but differences are evident in different vascular beds. This study investigates the contributions of P-selectin to neutrophil emigration into the cornea following central epithelial abrasion. Methods: Re-epithel...

  7. NK cells modulate the inflammatory response to corneal epithelial abrasion and thereby support wound healing

    Science.gov (United States)

    Natural killer cells are lymphocytes of the innate immune system that have crucial cytotoxic and regulatory roles in adaptive immunity and inflammation. Herein, we consider a role for these cells in corneal wound healing. After a 2-mm central epithelial abrasion of the mouse cornea, a subset of clas...

  8. PAGMan - propelled abrasive grit to manage weeds in soybean and corn

    Science.gov (United States)

    New tools for controlling weeds would be useful for soybean and corn production in organic systems or in systems in which weeds developed resistance to multiple herbicides. Here we report on two developments: (i) the safety to soybean seedlings of using air-propelled abrasive grit (PAG) for managing...

  9. Air-propelled abrasive grit for postemergence in-row weed control in field corn

    Science.gov (United States)

    Organic growers need additional tools for weed control. A new technique involving abrasive grit propelled by compressed air was tested in field plots. Grit derived from corn cobs was directed at seedlings of summer annual weeds growing at the bases of corn plants when the corn was at differing early...

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

    NARCIS (Netherlands)

    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 a

  11. Toothbrush abrasion, simulated tongue friction and attrition of eroded bovine enamel in vitro

    NARCIS (Netherlands)

    Vieira, A.; Overweg, E.; Ruben, J. L.; Huysmans, M. C. D. N. J. M.

    2006-01-01

    Objectives: Enamel erosion results in the formation of a softened layer that is susceptible to disruption by mechanical factors such as brushing abrasion, tongue friction and attrition. The aim of this study was to investigate the individual contribution of those mechanical insults to the enamel los

  12. Tapered toothbrush filaments in relation to gingival abrasion, removal of plaque and treatment of gingivitis

    NARCIS (Netherlands)

    Versteeg, P.A.; Piscaer, M.; Rosema, N.A.M.; Timmerman, M.F.; van der Velden, U.; van der Weijden, G.A.

    2008-01-01

    Objectives: To compare a tapered filament toothbrush (TFTB) to a control toothbrush (ADA) in their potential to cause gingival abrasion and improve the gingival condition following a period of experimental gingivitis. Methods: Thirty-two subjects refrained from brushing mandibular teeth for 21 days.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Raman study of diamond-based abrasives, and possible artefacts in detecting UHP microdiamond

    Science.gov (United States)

    Nasdala, Lutz; Steger, Simon; Reissner, Claudia

    2016-11-01

    Raman spectral characteristics of a range of diamond-based abrasives (powders and sprays) and drilling and cutting tools, originating from preparation laboratories worldwide, are presented. Some abrasives show strong broadening of the main diamond band [FWHM (full width at half band-maximum) > 5 cm- 1] accompanied by strong band-downshift (ν˜ = 1316-1330 cm- 1). Others are characterised by moderate band broadening (FWHM = 1.8-5 cm- 1) at rather regular band position (ν˜ = 1331-1333 cm- 1). In addition we found that a ;fresh; abrasive and its used analogue may in some cases show vast differences in their Raman spectra. The Raman parameters of diamond-based abrasives overlap widely with Raman parameters of UHP (ultra-high pressure) microdiamond. It is hence impossible to assign diamond detected in a geological specimen to either an introduced artefact or a genuine UHP relict, from the Raman spectrum alone. Raman is an excellent technique for the detection of minute amounts of diamond; however it does not provide conclusive evidence for the identification of UHP microdiamond. The latter requires thorough verification, for instance by optical microscopy or, if doubts cannot be dispelled, transmission electron microscopy.

  15. Estudo multicasos sobre atividades inovativas

    Directory of Open Access Journals (Sweden)

    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.

  16. Structural transformations and wear resistance of abrasive-affected amorphous Fe- and Co-based alloys

    Science.gov (United States)

    Korshunov, L. G.; Chernenko, N. L.

    2008-12-01

    The abrasive wear resistance of the Fe64Co30Si3B3, Fe82.6Nb5Cu3Si8B1.4, Co86.5Cr4Si7B2.5, and Fe81Si4B13C2 amorphous alloys (ribbon 30 μm thick) has been investigated upon sliding over fixed abrasives (corundum and silicon carbide). The character of fracture of the surface and structural transformations initiated in these materials by the abrasive action have been studied by the metallographic, X-ray diffraction, and electron-microscopic methods. It has been shown that the abrasive wear resistance of the amorphous alloys is smaller by a factor of 1.6-2.9 than that of the Kh12M and U8 tool steels possessing approximately the same level of hardness. A pronounced softening of the surface layer of the amorphous alloys in the process of wear, which is characterized by a decrease in their microhardness reaching 12.5%, has been found. It has been shown that in the surface layer of these amorphous alloys upon wear there arises a small amount (on the order of several volume percent) of the nanocrystalline structure, which does not exert a marked effect on the microhardness and wear resistance of the alloys. In the alloys under study, the main factor that is responsible for their comparatively low abrasive wear resistance is their local softening in the process of wear caused by specific features of deformation processes occurring heterogeneously under the action of high shear contact stresses.

  17. Patient preference: conventional rotary handpieces or air abrasion for cavity preparation.

    Science.gov (United States)

    Malmström, Hans S; Chaves, Yvette; Moss, Mark E

    2003-01-01

    It has been suggested that patients should accept the use of the air abrasion technique over the conventional handpiece due to the reduced need for anesthesia. Technologies for both air abrasion and the conventional rotary handpiece have, in recent decades, seen major improvements, but there are no recent scientific publications that evaluate the patient's preference for these two technologies when performing a cavity preparation. This study determined the patient's preference for air abrasion or the rotary handpiece for removing occlusal fissure carious lesions in mandibular premolars. Ten healthy subjects 18 years of age or older were recruited from the General Dentistry Clinic of the University of Rochester Eastman Dental Center, with fissure caries at a DEJ depth of similar size (determined by radiographs and clinical examination) in any two mandibular premolars in opposite quadrants. Within each subject, the two methods of caries removal were randomly assigned. In one premolar, air abrasion was used for cavity preparation, and in the other premolar, a conventional rotary handpiece was used. At each visit prior to treatment, the patients were instructed to complete the Emotional Status (ES) questionnaire (SUNY University at Buffalo Craniofacial Pain Clinic) to assess differences in their emotional status between appointments. At each appointment, when the restorative treatment was completed, patients were instructed to rate their pain on the Visual Analogue Scale (VAS). A technique preference questionnaire was given after the second appointment. The subjects rated the perception of pain as significantly lower (p cavity preparation when removing fissural caries in mandibular premolars and most subjects did not experience any pain when air abrasion was used.

  18. Pulmonary sporotrichosis: case series and systematic analysis of literature on clinico-radiological patterns and management outcomes.

    Science.gov (United States)

    Aung, Ar Kar; Teh, Bing Mei; McGrath, Christopher; Thompson, Philip J

    2013-07-01

    Pulmonary infections by Sporothrix spp. manifest radiologically as cavitary or non-cavitary disease depending on whether the infection is primary pulmonary or multifocal sporotrichosis. Despite current guidelines, the optimal management for pulmonary sporotrichosis remains unclear. In order to clarify this, we present two cases of pulmonary sporotrichosis, as well as the results of a comprehensive literature review of treatment outcomes based on clinico-radiological presentation patterns of the disease. A literature search of all case reports in English language over the last 50 years (1960-2010) was conducted. Data on patient characteristics, risk factors, clinico-radiological patterns, treatment modalities and outcomes were collected and analyzed. A total of 86 cases were identified, i.e., 64 (74.4%) primary pulmonary and 22 (25.6%) multifocal sporotrichosis. Radiologically, primary pulmonary disease was commonly characterized by cavity formation which was lacking in multifocal infections (P = 0.0001). Immunosuppressant use was more common in multifocal sporotrichosis (P = 0.0001), while hemoptysis was more common in primary pulmonary form (P = 0.01). No other differences in patient characteristics or risk factors were noted. Extra-pulmonary multifocal sporotrichosis most commonly involved skin (81.8%) and joints (45.4%). For patients with cavitary primary pulmonary sporotrichosis, outcomes from medical therapy alone were inferior to surgical intervention (P = 0.02). However, for both primary pulmonary and multifocal sporotrichosis with non-cavitary disease, medical therapy alone provided good outcomes. Only 12 (16.7%) cases were treated with itraconazole. Treatment of pulmonary sporotrichosis should be guided by the clinico-radiological patterns of presentation. Medical therapy alone is likely sufficient for non-cavitary disease while early surgery should be considered for cavitary primary pulmonary sporotrichosis. The experience in treating cavitary disease

  19. Medication adherence among Nigerians with schizophrenia: correlation between clinico-demographic factors and quality of life

    Directory of Open Access Journals (Sweden)

    Oluseun P. Ogunnubi

    2017-03-01

    Full Text Available Medication adherence contributes significantly to symptom remission, recovery and wellbeing in mental illnesses. We evaluated how medication adherence correlates with clinico-demographic factors and quality of life (QoL in a sample of Nigerians with schizophrenia. This descriptive crosssectional study involved 160 randomly selected participants with confirmed diagnosis of schizophrenia based on MINI International Neuropsychiatric Interview. Data on socio-demographic and clinical characteristics of participants were collected with a questionnaire. Medication adherence was assessed with Morisky Medication Adherence Questionnaire, and participants completed the World Health Organization Quality of Life Scale-BREF. The mean age of participants was 38.54 (±11.30 years, and all the participants were on antipsychotics, but only 45% were adherent to their medication. Out of all the participants, 45 (28.2% considered their overall QoL to be good, 97 (60.6% considered theirs to be fair, while 18 (11.2% reported poor QoL. Medication non-adherence correlated negatively with good QoL across multiple dimensions including overall QoL (r=- 0.175, health satisfaction (r=-0.161, physical (r=-0.186 and psychological domain (r=-0.175. Again, participant’s age (r=- 0.190 and age of onset of illness (r=-0.172 correlated negatively with medication nonadherence, and a trend towards relapse delay with medication adherence was also observed (r=-0.155. The effect size of these correlations were however small. Our findings suggest a link between medication adherence and QoL in schizophrenia, such that strategy that addresses medication nonadherence and its determinants may have potential benefits on wellbeing. Further hypotheses-driven studies are desirable.

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

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    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

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

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    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.

  2. Lichen simplex chronicus of anogenital region: A clinico-etiological study

    Directory of Open Access Journals (Sweden)

    R Rajalakshmi

    2011-01-01

    Full Text Available Background: Lichen simplex chronicus (LSC of the anogenital region, is a benign, extremely uncomfortable disease. Aims: As very little is known about the cause of anogenital LSC (AGLSC, we undertook this study to determine various clinico-etiological factors involved in it and to assess the frequency of AGLSC. Methods: This was a descriptive study, including 105 patients with AGLSC, who attended the Dermatology clinic in our institute from September 2007 to June 2009. Detailed history, physical examination, and relevant investigations were done. The collected data were tabulated and analyzed. Results: The frequency of AGLSC among patients presenting with anogenital pruritus was 2.54%. Primary AGLSC was more common than secondary AGLSC (69.5% vs. 30.5%. AGLSC manifested more commonly in males than in females (56.2% vs. 43.8%. The mean duration of the disease was 30.6 months. The common triggering factors for itching were sweating (41.9%, rubbing of thighs while walking for long distances (9.5%, and mental stress (5.7%. Pruritus of AGLSC was related to the intake of various food items in 37.1% of patients. In males, scrotum was the predominant site involved (89.8%, whereas in females, labia majora was the predominant site involved (78.2%. Nearly one-third of cases (30.5% of AGLSC had some other dermatoses in the anogenital region. Conclusions: Though psychological factors are thought to play an important role in disease causation and perpetuation among AGLSC patients, their significance could not be ascertained by us.

  3. Clinico-pathological nomogram for predicting BRAF mutational status of metastatic colorectal cancer

    Science.gov (United States)

    Loupakis, Fotios; Moretto, Roberto; Aprile, Giuseppe; Muntoni, Marta; Cremolini, Chiara; Iacono, Donatella; Casagrande, Mariaelena; Ferrari, Laura; Salvatore, Lisa; Schirripa, Marta; Rossini, Daniele; De Maglio, Giovanna; Fasola, Gianpiero; Calvetti, Lorenzo; Pilotto, Sara; Carbognin, Luisa; Fontanini, Gabriella; Tortora, Giampaolo; Falcone, Alfredo; Sperduti, Isabella; Bria, Emilio

    2016-01-01

    Background: In metastatic colorectal cancer (mCRC), BRAFV600E mutation has been variously associated to specific clinico-pathological features. Methods: Two large retrospective series of mCRC patients from two Italian Institutions were used as training-set (TS) and validation-set (VS) for developing a nomogram predictive of BRAFV600E status. The model was internally and externally validated. Results: In the TS, data from 596 mCRC patients were gathered (RAS wild-type (wt) 281 (47.1%); BRAFV600E mutated 54 (9.1%)); RAS and BRAFV600E mutations were mutually exclusive. In the RAS-wt population, right-sided primary (odds ratio (OR): 7.80, 95% confidence interval (CI) 3.05–19.92), female gender (OR: 2.90, 95% CI 1.14–7.37) and mucinous histology (OR: 4.95, 95% CI 1.90–12.90) were independent predictors of BRAFV600E mutation, with high replication at internal validation (100%, 93% and 98%, respectively). A predictive nomogram was calculated: patients with the highest score (right-sided primary, female and mucinous) had a 81% chance to bear a BRAFV600E-mutant tumour; accuracy measures: AUC=0.812, SE:0.034, sensitivity:81.2% specificity:72.1%. In the VS (508 pts, RAS wt: 262 (51.6%), BRAFV600E mutated: 49 (9.6%)), right-sided primary, female gender and mucinous histology were confirmed as independent predictors of BRAFV600E mutation with high accuracy. Conclusions: Three simple and easy-to-collect characteristics define a useful nomogram for predicting BRAF status in mCRC with high specificity and sensitivity. PMID:26575603

  4. Hemato-biochemical and clinico-epidemiological aspects of parturient hemoglobinuria in Nili-Ravi buffaloes

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    A. Khan

    2010-02-01

    Full Text Available For this study, 60 buffaloes suffering from parturient hemoglobinuria (PHU were randomly selected from field cases occurring in three districts of Punjab, Pakistan and simultaneously, 60 clinically healthy buffaloes of similar description from the same localities were included for case control study. Clinico-epidemiological data were collected. Blood/serum samples from all buffaloes were collected and analyzed. The most prominent clinical sign was passing of red to coffee colored urine. Milk production was reduced and respiration and pulse rates were significantly accelerated. Ruminal motility was significantly weak and reduced along with characteristic straining while defecating. The case fatality was 15%. A significantly high occurrence of PHU was observed in the winter season (41.8%. Maximum number of affected buffaloes (25.0% was in 4th lactation. Twenty-seven (45.0% buffaloes developed hemoglobinuria in the post calving period and majority (59.3% of these were within 1-23 days of calving. Of the 33 (55.0% PHU affected pregnant buffaloes, 18 (54.6% were in their third trimester. The highest cases of PHU were observed in buffaloes producing 10 or more liters of milk/day (42.5%. Recurrence of PHU was observed in 18.3% buffaloes. Mean values of total erythrocyte counts, hemoglobin concentration and packed cell volume were lower (P<0.001, while erythrocyte sediment rate was higher (P<0.001 in PHU affected buffaloes as compared to the values in healthy buffaloes. Neutrophils were significantly higher, while lymphocytes and erythrocytic glucose-6-phosphate dehydrogenase (G6PD were lower, in PHU affected buffaloes than in healthy buffaloes. Serum phosphorus, copper and selenium were significantly (P<0.001 lower, whereas potassium, iron and molybdenum (P<0.001 were higher in buffaloes suffering from PHU than healthy buffaloes.

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

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    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.

  6. Clinico-Epidemiological study of poisoning in a tertiary care hospital in Bangladesh

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    Rabiul Hossain

    2017-01-01

    Full Text Available Objective: The scale of the problem of poisoning is enormous hence clinico epidemiological spectrum of all poisoning cases need to explore to generate the management tool. Methods: This prospective study was done at two medicine units (Unit 5 and 10 of Dhaka Medical College Hospital from July to December 2010 where all poisoning cases were seen. A total of 2890 patients were admitted out of which 600 were taken into the study. Results: Among the poisoning cases 29% were pesticide, 27% travel related poisoning, and 20% benzodiazepine. 70% of poisoning occurred below 30 years of age and male: female ratio was 3:2. Incidence of poisoning was highest among students (31% and housewives (25%. Majority of the patients were from urban area (76% and most common intention was suicidal (66%. Familial disharmony was the prime cause (63% behind poisoning. 42% cases got admitted between 5-8 hours of poisoning and more than 80% patients were admitted in the hospital directly without getting any first aid anywhere. Sixty-eight percent had Glasgow coma scale (GCS score above 10 during admission. Cardinal clinical features of poisoning were nausea/vomiting (63%, drowsiness (56%, miosis (31%. Seventy percent patients were treated with only general and supportive treatment and specific antidotes were used in 30% cases. Case fatality for pesticide, benzodiazepine/anti-psychotic, rodenticide and snake bite was 6.9%, 2.2%, 8.3% and 3.3% respectively. Conclusion: To assess the magnitude of problem, awareness of the public for prevention, immediate first aid measures and quick hospital admission is crucial component of poisoning.

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

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    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.

  8. A CLINICO - MICROBIOLOGICAL STUDY OF PYODERMA WITH SPECIAL REFERENCE TO MRSA

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    Animesh

    2015-04-01

    Full Text Available BACKGROUND AND OBJECTIVES: Pyoderma refers to pyogenic infection of the skin. Staphylococcus aureus is one of the most common pathogen in pyoderma and due to indiscriminate use of antibiotics it has lead to development of resistant strains known to be sensitive before. AIMS: A clinico - microbiological study of pyoderma with special reference to MRSA. SETTINGS AND DESIGN: STUDY DESIGN: Cross - sectional study . STUDY SETTING: O.P.D of Dermatology Department. STUDY SUBJECTS : Patients of all age groups,both gender, attending De rmatology out patient department were incorporated. STUDY SAMPLE: 200 patients with Pyoderma attending the O.P.D in 1 year. STUDY PERIOD: 6 Months . METHODS: In this cross sectional study, 200 patients of either sex and all age groups diagnosed as pyoderma and having frank pustular lesion were included after detailed history and examination. A sample of pus was collected taking aseptic precautions with the help of sterile swabs and investigated for antibiotic sensitivity pattern of isolated organism. RESULT S: Out of 200 patients of indoor and outpatient department Single isolates were yielded in 166 patients and multiple organisms were isolated in 7 patients and there was no growth in 27 patients. Coagulase positive Staphylococcus was the commonest isolate i .e. 142 organisms, among which MRSA was 41 (23%. Highest susceptibility was seen to Chloramphenicol 100%, Teicoplatin 100%, Vancomycin 99% Amikacin 90%, Linezolid 82%, Clindamycin 76%, Gentamicin 67% . Most Resistant drugs were Cefoperazone 100%, Cefotaxime 100% , Cephazolin 100%, Penicillin - G 100 %, Cefipime 90%,Cefipime 90%, erythromycin 77% ciprofloxacin 75%, Cotrimoxazole 63% & cefoxitin showed 52% resistance. CONCLUSION: Though Pyodermas are common skin problem often because of therapeutic failure and due to resistance of organism and emergence of MRSA stains to antibiotics it becomes difficult to treat. Hence, the study of culture and sensitivity can be highly

  9. Evaluation of clinico-pathological features and Helicobacter pylori infection in gastric inflammatory fibroid polyps.

    Science.gov (United States)

    Albuquerque, Andreia; Rios, Elisabete; Carneiro, Fátima; Macedo, Guilherme

    2014-12-01

    Inflammatory fibroid polyps are rare mesenchymal lesions. The frequency of Helicobacter pylori infection in the gastric mucosa overlying inflammatory fibroid polyps and its relation with the histologic features of the polyps are undetermined. The clinico-pathological features of inflammatory fibroid polyps, the frequency of Helicobacter pylori infection in the overlying gastric mucosa, and its putative impact on the phenotype of the polyps were evaluated. Gastric inflammatory fibroid polyps diagnosed in our Hospital from 1998 to 2012 were reviewed and the histological. The histological sections were stained with hematoxylin and eosin and modified Giemsa for the evaluation of Helicobacter pylori infection. Inconclusive cases were further analyzed by immunohistochemistry with anti-Helicobacter pylori antibody. Diagnosis was confirmed in 54 polyps, 85 % developed in females, mean age 63 ± 11 years. Most polyps were sessile (74 %), with a mean size of 15 ± 12 mm, 96 % were located in the antrum and 85 % were removed by snare polypectomy. Helicobacter pylori infection was identified in 48 % of the polyps. Most inflammatory fibroid polyps developed in the submucosa, and mucosal extension was observed in 96 % of the cases. Chronic gastritis was observed in all cases (63 % with activity, 31 % with intestinal metaplasia, and 61 % with foveolar hyperplasia). Erosion and ulceration of the overlying gastric mucosa was observed in 48 % and 11 % of the polyps, respectively. Onion skin features were present in 52 % of the polyps and were more frequently observed in cases without evidence of Helicobacter pylori infection. Background changes in gastric mucosa were not distinctive according to Helicobacter pylori infection. Chronic atrophic gastritis with intestinal metaplasia was associated with the presence of perivascular onion skin lesions. To our knowledge, this is the second largest series of gastric inflammatory fibroid polyps. Helicobacter pylori infection was

  10. Expression of Hpa and CD222 in bladder carcinoma and analysis of clinico-pathologic correlation

    Institute of Scientific and Technical Information of China (English)

    Shuhong Shi; Hui Zhang

    2014-01-01

    Objective:Our study aimed to investigate the relationships between the clinico-pathologic features and the hepa-ranase (Hpa) and CD222 expressions in bladder carcinoma. Methods:The expressions of Hpa and CD222 in 95 bladder carcinoma specimens and 20 paraneoplastic bladder tissues (controls) were assessed using the immunohistochemical stain-ing method. Results:The positive expression rates of Hpa and CD222 in bladder carcinoma were 68.42%and 61.05%, respectively. The positive rate of Hpa was significantly higher in the carcinoma specimens than in the control specimens (P<0.01). Similarly, the Hpa expression in the invasive bladder carcinoma was significantly higher than that in the non-invasive bladder carcinoma (P<0.01). A positive correlation was observed between the expressions of Hpa and CD222 (P<0.05). The expressions of Hpa and CD222 were significantly correlated with lymphatic invasion and TNM staging (P<0.05). The 5-year survival rate was significantly higher in negative expression of the Hpa group than that in the positive expression group (P<0.05). Compared with the non-co-positive expression group, the 5-year survival rate in the co-positive expression of Hpa and CD222 group was significantly lower (P<0.05). Conclusion:High Hpa and CD222 expressions in tumor tissues were associated with the occurrence and development of bladder carcinoma. Our results provide helpful information for the further diagnosis and therapy of bladder carcinoma.

  11. Sporadic versus hereditary gastrinomas of the duodenum and pancreas: Distinct clinico-pathological and epidemiological features

    Institute of Scientific and Technical Information of China (English)

    Martin Anlauf; Wolfram T Knoefel; Henning Dralle; Paul Komminoth; Philipp U Heitz; Aurel Perren; Günter Kl(o)ppel; Nele Garbrecht; Tobias Henopp; Anja Schmitt; Regina Schlenger; Andreas Raffel; Markus Krausch; Oliver Gimm; Claus F Eisenberger

    2006-01-01

    Gastrinomas are defined as gastrin secreting tumors that are associated with Zollinger-Ellison syndrome (ZES). ZES is characterized by elevated fasting gastrin serum levels, positive secretin stimulation test and clinical symptoms such as recurrent peptic ulcer disease, gastroesophageal reflux disease and occasional diarrhea. Genetically, nonhereditary (sporadic) gastrinomas are distinguished from hereditary gastrinomas, which are associated with multiple endocrine neoplasia type 1 (MEN1) syndrome. In general, duodenal gastrinomas are small and solitary if they are sporadic and multiple as well as hereditary. The sporadic gastrinomas occur in the duodenum or in the pancreas while the hereditary gastrinomas almost all occur in the duodenum. Our series of 77 sporadic duodenal neuroendocrine tumors (NETs) includes 18 patients (23.4%) with gastrinomas and ZES. Of 535 sporadic NETs in the pancreas collected from the NET archives of the departments of pathology (4.5%) suffered from sporadic pancreatic gastrinomas and ZES. These NETs have to be distinguished from tumors with immunohistochemical positivity for gastrin but without evidence of ZES. An additional 19 patients suffered from MEN1 and ZES. These patients showed exclusively duodenal gastrinomas, but not pancreatic gastrinomas. The prognosis of sporadic and MEN1-associated duodenal gastrinomas is better than that of pancreatic gastrinomas, since they progress slowly to liver metastasis. In summary, sporadic and MEN1-associated gastrinomas in the duodenum and pancreas show different clinico-pathological and genetic features. The incidence of sporadic duodenal gastrin-producing tumors is increasing, possibly due to optimized diagnostic procedures. In contrast, pancreatic MEN1-associated gastrinomas seem to be extremely rare. A considerable subset of tumors with immunohistochemical expression of gastrin but without evidence of ZES should be designated as functionally inactive NETs expressing gastrin, but not as

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

    Science.gov (United States)

    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

  13. Preparation of Ce-doped colloidal SiO{sub 2} composite abrasives and their chemical mechanical polishing behavior on sapphire substrates

    Energy Technology Data Exchange (ETDEWEB)

    Lei, Hong, E-mail: hong_lei2005@aliyun.com [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China); Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China); Tong, Kaiyu; Wang, Zhanyong [School of Materials Science and Engineering, Shanghai Institute of Technology, Shanghai 201418 (China)

    2016-04-01

    Chemical mechanical polishing (CMP) has become a widely accepted global planarization technology. Abrasive is one of key elements during CMP process. In order to enhance removal rate and improve surface quality of sapphire substrate, a series of novel Ce-doped colloidal SiO{sub 2} composite abrasives were prepared by chemical co-precipitation method. The CMP performances of the Ce-doped colloidal SiO{sub 2} composite abrasives on sapphire substrate were investigated by using UNIPOL-1502 polishing equipment. The analyses on the surface of polished sapphire substrate indicate that slurries containing the Ce-doped colloidal SiO{sub 2} composite abrasives exhibit lower surface roughness, higher material removal rate than that of pure colloidal SiO{sub 2} abrasive under the same testing conditions. Furthermore, the acting mechanism of the Ce-doped colloidal silica in sapphire CMP was investigated. X-ray photoelectron spectroscopy analysis shows that solid-state chemical reactions between Ce-doped silica abrasives and sapphire surface occur during CMP process, which can promote the chemical effect in CMP and lead to the improvement of material removing rate. - Highlights: • Novel Ce-doped colloidal SiO{sub 2} composite abrasives were prepared. • The chemical mechanical polishing (CMP) performances of the composite abrasives on sapphire substrate were investigated. • Novel composite abrasives show excellent polishing characteristics comparison with pure colloidal SiO{sub 2} abrasive. • We explore and report the acting mechanism of composite abrasives to sapphire CMP.

  14. Selected Plastics Wear Resistance to Bonded Abrasive Particles Compared to Some Ferrous Materials

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    Milan Brožek

    2015-01-01

    Full Text Available Plastics are macromolecular materials without we cannot imagine any branch of human activity with. Plastics have unique properties, often very different from metals. At the choice of the concrete plastic for the concrete application it is necessary to evaluate its mechanical, physical, chemical and technological properties. In last years producers offer also plastics for production of parts exposed to different types of wear. In the contribution the results of wear resistance studying of 10 types of plastics (PTFE, PVC, POM-C, PC, PETP, PEEK, PA66, PP, PA6E and PE-UHMW of one producer are published and compared with test results of four different Fe alloys (grey iron, structural steel, cast steel wear resistant and high-speed steel. The laboratory tests were carried out using the pin-on-disk machine with abrasive cloth (according to ČSN 01 5084, when the abrasive clothes of three different grits (240, 120 and 60 were used. It corresponds to the average abrasive grain sizes of 44.5 µm, 115.5 µm and 275 µm. During the test the test sample was pressed to the abrasive cloth by the pressure of 0.1 MPa. The wear intensity was assessed by the volume, weight and length losses of tested samples. The technical-economical evaluation was the part of the carried out tests. It was univocally proved that at the intensive abrasive wear using the abrasive cloth the best results shows the High-Speed Steel HSS Poldi Radeco 19 810 according to ČSN 41 9810, although its price is relatively high. Other tested Fe alloys, namely grey iron according to ČSN 42 2415, structural steel 11 373 according to ČSN 41 1373 and wear resistant cast steel VPH 6 showed also very favourable properties at the material low price. In comparison with Fe alloys the wear of all plastics was considerably higher and the plastics were considerably more expensive.

  15. Abrasion and erosion testing of materials used in power production from coal

    Energy Technology Data Exchange (ETDEWEB)

    Tylczak, Joseph H.; Adler, Thomas A.; Rawers, James C.

    2003-09-01

    The Albany Research Center (ARC) has a long history of studying abrasive wear, related to mineral testing, handling, and processing. The center has also been instrumental in the design and development of wear test procedures and equipment. Research capabilities at ARC include Pin-on-Drum, Pin-on-Disk, and Dry Sand/Rubber Wheel abrasion tests, Jaw Crusher gouging test, Ball-on-Ball Impact test, and Jet erosion tests. Abrasive and erosive wear studies have been used to develop both new alloys and improved heat treatments of commercial alloys. As part of ARC’s newest iteration on wear testing to evaluate materials for use in new and existing pulverized coal combustion and gasifier power systems, the ARC has designed and constructed a new High Temperature Hostile Atmosphere Erosion Wear Test (HAET). This new piece of test apparatus is designed for erosive particle velocities of 10-40 m/sec and temperatures from room temperature (23°C) to 800+°C, with special control over the gas atmosphere. A variable speed whirling arm design is used to vary the impact energy of the gravity fed erosive particles. The specimens are mounted at the edge of a disk and allow a full range of impingement angles to be selected. An electric furnace heats the specimens in an enclosed retort to the selected temperature. Tests include both oxidizing conditions and reducing conditions. A range of gases, including CO, CO2, CH4, H2, H2S, HCl, N2, O2, and SO2 can be mixed and delivered to the retort. During the erosion testing a stream of abrasive powder is delivered in front of the specimens. This apparatus is designed to use low abrasive fluxes, which simulate real operating conditions in commercial power plants. Currently ~270 μm SiO2 particles are being used to simulate the abrasive impurities typically found in coal. Since operators are always striving for longer lifetimes and higher operating temperatures, this apparatus can help elucidate mechanisms of wastage and identify superior

  16. CLINICO-ECONOMICAL ANALYSIS OF THE TREATMENT EFFICACY IN PATIENTS WITH ARTERIAL HYPERTENSION OF 1-2 DEGREES

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    L. A. Haisheva

    2016-01-01

    Full Text Available Aim. Clinico-economical analysis of arterial hypertension (HT treatmentMaterial and methods. 78 patients with HT were involved into the study. Patients were spitted into two groups depending on HT degree. The first group – 38 patients with HT 1 degree. The second one – 40 patients with HT 2 degree. Patients of group 1 had initial antihypertensive therapy with angiotensinconverting enzyme inhibitors. If target level of blood pressure (BP had not been reached, therapy was changed on fixed combination of lisinopril and hydrochlorothiazide. Patients of group 2 had initial combined antihypertensive therapy with lisinopril and hydrochlorothiazide. If it was needed amlodipine maleat was added. Clinico-economical analysis was performed according to “cost-efficacy” approach at the end of 3 month therapy.Results. About 50% of hypertensive patients do not follow physician recommendations in out-patient practice. They decrease a dose of medicine or stop therapy themselves. More than 6% of them perform self-treatment.Conclusion. Analysis showed that therapy of patients with HT of 1 degree is economically more profitable regarding target BP achievement. It is more reasonable to start antihypertensive therapy with fixed low dose combination and add calcium antagonists if it is needed in patients with HT of 2 degree.

  17. CLINICO-ECONOMICAL ANALYSIS OF THE TREATMENT EFFICACY IN PATIENTS WITH ARTERIAL HYPERTENSION OF 1-2 DEGREES

    Directory of Open Access Journals (Sweden)

    L. A. Haisheva

    2009-01-01

    Full Text Available Aim. Clinico-economical analysis of arterial hypertension (HT treatmentMaterial and methods. 78 patients with HT were involved into the study. Patients were spitted into two groups depending on HT degree. The first group – 38 patients with HT 1 degree. The second one – 40 patients with HT 2 degree. Patients of group 1 had initial antihypertensive therapy with angiotensinconverting enzyme inhibitors. If target level of blood pressure (BP had not been reached, therapy was changed on fixed combination of lisinopril and hydrochlorothiazide. Patients of group 2 had initial combined antihypertensive therapy with lisinopril and hydrochlorothiazide. If it was needed amlodipine maleat was added. Clinico-economical analysis was performed according to “cost-efficacy” approach at the end of 3 month therapy.Results. About 50% of hypertensive patients do not follow physician recommendations in out-patient practice. They decrease a dose of medicine or stop therapy themselves. More than 6% of them perform self-treatment.Conclusion. Analysis showed that therapy of patients with HT of 1 degree is economically more profitable regarding target BP achievement. It is more reasonable to start antihypertensive therapy with fixed low dose combination and add calcium antagonists if it is needed in patients with HT of 2 degree.

  18. Clinico-pathological features of patients with melanoma and positive sentinel lymph node biopsy: a single institution experience.

    Science.gov (United States)

    Homolak, Damir; Šitum, Mirna; Čupić, Hrvoje

    2015-01-01

    Sentinel lymph node biopsy (SLNB) is an established method for the assessment of tumor aggressiveness in patients with primary cutaneous melanoma (PCM). To improve the criteria for the selection of SLNB candidates, the aim of our study was to determine clinico-pathohistological parameters that can serve as predictors of metastatic progression. We retrospectively evaluated all available clinico-pathohistological parameters in 844 patients with PCM diagnosed between January 1, 2005 and December 31, 2010. SLNB was conducted in 484 (57.3%) patients, 122 (14.5%) of whom had a positive node. The association between predictors and SLNB outcomes (positive SLNB and metastatic development) was tested using logistic regression analysis. The main predictors of positive SLNB were Breslow thickness (adjusted odds ratio (AOR)=1.22; 95% confidence interval (CI)=1.11-1.33), Clark levels (AOR=1.78; 95% CI=1.31-2.40), ulceration (AOR=3.1; 95% CI=1.65-5.81), microsatellitosis, gender, and tumor localization. The predictors of metastatic spread were Breslow thickness (AOR=1,69; 95% CI=1.51-1.89), Clark level (AOR=3.59; 95% CI=2.79-4.62), nodular type of melanoma (AOR=8.21; 95% CI=1.70-39.53), ulceration, mitotic rate, microsatellitosis, gender, and tumor localization. It seems that these parameters should be taken into consideration when selecting patients for SLNB since tumor thickness is not a sufficient predictor of SLNB outcome, particularly in case of very thin lesions.

  19. Motor neuron diseases in the university hospital of Fortaleza (Northeastern Brazil): a clinico-demographic analysis of 87 cases.

    Science.gov (United States)

    Castro-Costa, C M; Oriá, R B; Vale, O C; Arruda, J A; Horta, W G; D'Almeida, J A; Santos, T J; Ramos, R S; Gifoni, M A

    2000-12-01

    In this retrospective (1980-1998) study, we have analyzed clinico-demographically, from the records of the University Hospital of Fortaleza (Brazil), a group of 87 patients showing signs and symptoms of motor neuron diseases (MNDs). Their diagnosis was determined clinically and laboratorially. The WFN criteria were used for amyotrophic lateral sclerosis (ALS) diagnosis. The clinico-demographic analysis of the 87 cases of MNDs showed that 4 were diagnosed as spinal muscular atrophy (SMA), 5 cases as ALS subsets: 2 as progressive bulbar paralysis (PBP), 2 as progressive muscular atrophy (PMA) and 1 as monomelic amyotrophy (MA), and 78 cases of ALS. The latter comprised 51 males and 27 females, with a mean age of 42.02 years. They were sub-divided into 4 groups according to age: from 15 to 29 years (n= 17), 30 to 39 years (n= 18), 40 to 69 years (n= 39) and 70 to 78 years (n= 4). From the 78 ALS patients, 76 were of the classic sporadic form whilst only 2 were of the familial form. The analysis of the 87 patients with MNDs from the University Hospital of Fortaleza showed a predominance of ALS patients, with a high number of cases of juvenile and early onset adult sporadic ALS.

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

    Science.gov (United States)

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

    2012-01-01

    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. 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 were analyzed. Fifteen patients with verrucous lesions of the oral cavity were treated with surgery as the primary modality. The mean age was 62.8 years (range 35-85 years). Wide excision of the primary lesion with adequate mucosal and soft-tissue margins was carried out. Free-flap reconstruction was done in eight patients. All patients remain loco-regionally controlled with good functional speech and swallowing outcome. Verrucous lesions of the oral cavity are a distinct clinical entity with varied histopathology. A surgical excision with wide margins and appropriate reconstruction is necessary to optimize the disease and functional outcome.

  1. Afericoes e exames clinicos realizados nos participantes do ELSA-Brasil

    Directory of Open Access Journals (Sweden)

    Jose Geraldo Mill

    2013-06-01

    Full Text Available Este artigo descreve os exames clínicos realizados no Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil. Alguns deles (antropometria, pressão arterial e índice tornozelo-braquial já têm uso clínico consolidado. Outros, como a velocidade de onda de pulso, variabilidade da frequência cardíaca e medida da espessura médio-intimal de carótidas, carecem de valor de referência na população brasileira não doente e podem constituir preditores importantes de desfechos cardiovasculares. A medida da pressão arterial após manobra postural foi incluída no ELSA-Brasil porque foi pouco testada em estudos epidemiológicos. O ELSA-Brasil inovou na realização do índice tornozelo-braquial, ao usar um aparelho automático em substituição à coluna de mercúrio na medida da pressão arterial, e também na medida do diâmetro ântero-posterior do lobo direito do fígado pela ultrassonografia, proposta para avaliação quantitativa da doença hepática gordurosa não-alcoólica. Os participantes são indivíduos mais jovens (a partir dos 35 anos do que em outras coortes focadas no estudo da aterosclerose subclínica. A inclusão de indivíduos mais jovens e a diversidade dos exames realizados tornam o ELSA-Brasil um estudo relevante no contexto da epidemiologia brasileira e internacional.

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

    Science.gov (United States)

    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.

  3. Effect of Fe2B boride orientation on abrasion wear resistance of Fe-B cast alloy

    Directory of Open Access Journals (Sweden)

    Da-wei Yi

    2017-07-01

    Full Text Available The microstructures and abrasion wear resistance of directional solidification Fe-B alloy have been investigated using optical microscopy, X-ray diffraction, scanning electron microscopy and laser scanning microscopy. The results show that the microstructure of as-cast Fe-B alloy consists of ferrite, pearlite and eutectic boride. After heat treatment, the microstructure is composed of boride and martensite. The plane which is perpendicular to the boride growth direction possesses the highest hardness. In two-body abrasive wear tests, the silicon carbide abrasive can cut the boride and martensite matrix synchronously, and the wear mechanism is micro cutting mechanism. The worn surface roughness and the wear weight loss both increase with the increasing contact load. Moreover, when the boride growth direction is perpendicular to the worn surface, the highest hardness plane of the boride can effectively oppose abrasion, and the martensite matrix can surround and support borides perfectly.

  4. Relationship among wear-resistance of three-body abrasion,substructure and property in martensite steels

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The effects of subsurface hardness on wear-resistance of martensitic steel 20Cr, 40CrSi, 60Mn, T8 and T10 in three-body abrasion under static load was investigated. It shows that the characteristic ofthe subsurface hardness distribution and the abrasive wear resistanceis related to the substructure near the worn surface. The substructure of the tested martensite steel has an apparent relationship with thecarbon content and steels with moderate carbon content and hardness exhibit good resistance to abrasive wear. The competition of the work-hardening effect and the temper softening effect, which resulted from deformation and friction heat generating during abrasive wear is considered to be a main reason for the relation among wear-resistance, hardness and substructure. At the test conditions, the wear-resistance of 40CrSi is the best.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  6. To Evaluate Effect of Airborne Particle Abrasion using Different Abrasives Particles and Compare Two Commercial Available Zirconia on Flexural Strength on Heat Treatment

    Science.gov (United States)

    Prasad, Hari A.; Pasha, Naveed; Hilal, Mohammed; Amarnath, G. S.; Kundapur, Vinaya; Anand, M; Singh, Sumeet

    2017-01-01

    specimens each. Heat treatment after airborne-particle abrasion using 50 µm Al2O3 particles and 50 µm silica coated Al2O3 are applied to the upper and lower surfaces of the specimens. Each specimen is held under a pressure of 30 psi for 15 seconds at a direction perpendicular to the surface and at a distance of 30mm with an airborne particle abrasion device for the specimens in the airborne particle abraded groups. Heat treatments were performed at a starting temperature of 500°C, heating rate of 100°c/ min, ending at a temperature of 1000°C and 15 minutes holding time without vacuum for the specimens in the group 4, 5, 9 and 10. Airborne-particle abrasion mimicking the preparation for cementation was applied to the lower surfaces with 50 µm alumina and silica coated alumina particles for the specimens in the groups 6, 7, 8, 9 and 10. The specimens were cleaned for 15 minutes in an ultrasonic bath containing distilled water. To determine the fracture strength, a disc of 10 mm diameter was used to place 3 hardened steel balls of 3 mm diameter separated each other by 120 degrees (described in the ISO standard 6872 for dental ceramics). Each specimen was centrally placed on this disc. The lower surface mimicking the internal surface of zirconia was the tension side, facing the supporting device testing, while the upper surface mimicking the external surface of the zirconia core was loaded with a flat punch (1 mm in diameter). A universal testing machine was used to perform the test at a cross head speed of 1mm/min. The failure stress was calculated with the equation listed in ISO 6872. The results were then statistically analyzed. A post hoc test was used for pair wise comparisons. Result: The mean fracture strength of commercially available Zirconia Ceramill (AMANNGIRBACH) showed a significant higher value compared to the ZR-White (UPCERA) Zirconia (P<0.001), Airborne abrasion treatment to the specimens showed a significant difference between the abraded groups and the

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

    Directory of Open Access Journals (Sweden)

    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.

  8. Study on NDT Fault Diagnosis of the Ball Bearing under Stage of Abrasion by Infrared Thermography

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Jin Ju; Hong, Dong Pyo [Chonbuk National University, Jeonju (Korea, Republic of); Kim, Won Tae [Kongju National University, Gongju (Korea, Republic of)

    2012-02-15

    For fault detection about the abrasion stage of rotational machineries under the dynamic loading conditions unlike the traditional diagnosis method used in the past decade, the infrared thermographic method with its distinctive advantages in non-contact, non-destructive, and visible aspects is proposed. In this paper, by applying a rotating deep-grooved ball bearing, passive thermographic experiments were conducted as an alternative way to proceeding the traditional fault monitoring on spectrum analyzer. As results, the thermographic experiment was compared with the traditional vibration spectrum analysis to evaluate the efficiency of the proposed method. Based on the results obtained as NDT, the temperature characteristics and abnormal fault detections of the ball bearing according to the abrasion stage were analyzed.

  9. Influence of scale-up on the abrasion of tablets in a pan coater.

    Science.gov (United States)

    Mueller, Ronny; Kleinebudde, Peter

    2006-11-01

    The purpose of this study was to examine the influence of batch size during scale-up on the abrasion and edge splitting of flat faced lactose tablets. The weight loss of white tracer tablets in a batch of blue coated tablets was investigated in a laboratory scale pan coater and a pilot scale pan coater as a function of different pan speeds and mixing times. It was observed that increasing batch size resulted in a decreased weight loss due to less edge damaging. The higher number of tablet impacts at the pan wall in the laboratory scale compared to the pilot scale might be the reason for this phenomenon. The common assertion that an increase in batch size in scale-up leads to a higher abrasion or tablet damaging was not supported in the current study.

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

    Indian Academy of Sciences (India)

    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.

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

    Directory of Open Access Journals (Sweden)

    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 %.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  13. Examining of abrasion resistance of hybrid composites reinforced with SiC and Cgr particles

    Directory of Open Access Journals (Sweden)

    M. Łągiewka

    2008-08-01

    Full Text Available The presented work discusses the influence of the type and volume percentage of particulate reinforcement consisting of mixed silicon carbide and graphite on the abrasion wear of hybrid composites with AlMg10 matrix. Also the macro photos of frictional surfaces have been shown and the results of hardness measurements have been presented. The performed examinations have allowed for stating that the mixture of SiC and Cgr particles changes in favour the tribological properties of the matrix alloy. It has been also proved that introducing hard reinforcing particles along with soft lubricating ones allows for achieving the material exhibiting high abrasion resistance, and moreover, the graphite particles protect the abraded surface from the destructive action of silicon carbide particles. Also hardness measurements have been performed and the resulting conclusion is that the composite hardness increases with an increase in volume fraction of the reinforcing particles.

  14. Abrasive wear resistance optimization of three different carbide coatings by the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Guer, Ali Kaya [Firat Univ., Elazig (Turkey). Dept. of Metallurgy and Materials; Kaya, Sinan [Firat Univ., Elazig (Turkey). Faculty of Technology

    2017-06-01

    In this study, FeCrC, SiC and B{sub 4}C powders were alloyed on the surface of AISI 430 ferritic stainless steel by plasma arc welding. The mass losses of the abrasive wear of the AISI 430 substrate were examined under the loads of 6, 10 and 16 N and in the distances of 10, 20 and 30 m by using Taguchi design method. The results of abrasive wear test were optimized by the minimum optimal control characteristics of the Taguchi procedure and the results were analyzed by using graphical methods. The Taguchi procedure is an important approach to achieve high quality without increasing the cost during the optimization of process parameters. The orthogonal planes of maximum effects of the controllable process parameters and minimum effects of uncontrollable process parameters were employed in the Taguchi method.

  15. Correlating field and laboratory rates of particle abrasion, Rio Medio, Sangre de Cristo Mountains, New Mexico

    Science.gov (United States)

    Polito, P. J.; Sklar, L. S.

    2006-12-01

    River bed sediments commonly fine downstream due to a combination of particle abrasion, selective transport of finer grains, and fining of the local sediment supply from hillslopes and tributaries. Particle abrasion rates can be directly measured in the laboratory using tumbling barrels and annular flumes, however, scaling experimental particle abrasion rates to the field has proven difficult due to the confounding effects of selective transport and local supply variations. Here we attempt to correlate laboratory and field rates of particle abrasion in a field setting where these confounding effects can be controlled. The Rio Medio, which flows westward from the crest of the Sangre de Cristo Mountains in north central New Mexico, is one of several streams studied by John P. Miller in the early 1960's. Several kilometers downstream of its headwaters, the river crosses the Picuris-Pecos fault. Upstream of the fault the river receives quartzite, sandstone and shale clasts from the Ortega Formation, while downstream sediments are supplied by the Embudo Granite. Because the upstream lithologies are not resupplied downstream of the fault, any observed fining of these clasts should be due only to abrasion and selective transport. We hypothesize that we can account for the effects of selective transport by comparing relative fining rates for the different upstream lithologies from both the field and a laboratory tumbler. By correlating laboratory abrasion rates with rock strength, we can predict the relative fining rates due solely to abrasion expected in the field; differences between the predicted and observed fining rates could then be attributed to selective transport. We used point counts to measure bed surface sediment grain size distributions at 15 locations along a 25 kilometer reach of the Rio Medio, beginning just downstream of the fault and ending upstream of a developed area with disturbed channel conditions. We recorded intermediate particle diameter as well

  16. The effectiveness of the air-powder abrasive device on the tooth and periodontium: an overview.

    Science.gov (United States)

    Kozlovsky, A; Soldinger, M; Sperling, I

    1989-01-01

    The characteristics of the air-powder abrasive device (APAD) was reviewed from the current dental literature and found to be an excellent alternative to traditional methods for stain and plaque removal. Access to crowded teeth, grooves and involved furcation areas are easily obtainable with less operator fatigue. The APAD slurry produces different root surface abrasiveness, depending on the method of use. Extended maintenance periods of exposed root surface using the APAD can result in an enormous loss of root structure. To avoid permanent damage of the root, the device should be used with overlapping strokes and root exposure to the APAD slurry should be minimized. The device can be used for total cementum removal with less operator fatigue and more reproducibility than with hand instruments, leaving smooth and clean surfaces. In addition, the device may be a valuable tool in the detoxification of root surfaces during periodontal surgery.

  17. A New Method for Descaling Wool Fibres by Nano Abrasive Calcium Carbonate Particles in Ultrasonic Bath

    Directory of Open Access Journals (Sweden)

    Ali rezaghasemi

    2016-08-01

    Full Text Available Up to now, the most conventional methods for descaling of wool fibre are based on chemical degradation and resin covering of scales or a combination of them. These methods are producing wastewater and can cover physical properties of the fibres beside scales orderly. In this study, a new and clean method is developed on the basis of abrasion effect of calcium carbonate Nano particles (CCNP in an ultrasonic bath. Woolen Samples (fibre and yarn were sonicated with different levels of CCNP. Tensile properties of the yarns, directional friction effect of the fibres and scanning electron microscope images of the fibres were studied. Test results showed that sonicated Nano treatment of woolyarn reduced its tenacity, extension and work of rupture and increased its coefficient of friction. Scanning electron microscope images of fibres and measurement of fibres directional displacement confirmed descaling of Nano abrasive treated wool samples in comparison to the raw wool.

  18. Structure and abrasive wear resistance of R6M5 steel-tungsten carbide composite coatings

    Science.gov (United States)

    Gnyusov, S. F.

    2012-09-01

    Features of the structure formation, composition, and abrasive wear resistance of R6M5 steel-tungsten carbide (R6M5-WC) composite coatings have been studied as dependent on the WC content. The introduction of ˜20 wt % WC into the hardening composition leads to an increase in the fraction of M6C carbide (in the form of eutectic inclusions with average size ˜5.9 μm at grain boundaries and dispersed ˜0.25 μm particles in the volume of grains), while a large proportion of metastable austenite (˜88 vol %) is still retained. The R6M5-WC coatings exhibit high abrasive wear resistance, which is ensured by the γ → α' martensite transformation during friction and a muiltimodal size distribution of hardening particles.

  19. Improvement of Surface Roughness Quality for Stainless Steel 420 Plate Using Magnetic Abrasive Finishing Method

    Directory of Open Access Journals (Sweden)

    Yahya M. Hamad

    2010-01-01

    Full Text Available An experimental study was carried out to improve the surface roughness quality of the stainless steel 420 using magnetic abrasive finishing method (MAF. Four independent operation parameters were studied (working gap, coil current, feed rate, and table stroke, and their effects on the MAF process were introduced. A rotating coil electromagnet was designed and implemented to use with plane surfaces. The magnetic abrasive powder used was formed from 33%Fe and 67% Quartz of (250µm mesh size. The lubricant type SAE 20W was used as a binder for the powder contents. Taguchi method was used for designing the experiments and the optimal values of the selected parameters were found. An empirical equation representing the relation between surface roughness with operation parameters have been achieved.

  20. Kerf modelling in abrasive waterjet milling using evolutionary computation and ANOVA techniques

    Science.gov (United States)

    Alberdi, A.; Rivero, A.; Carrascal, A.; Lamikiz, A.

    2012-04-01

    Many researchers demonstrated the capability of Abrasive Waterjet (AWJ) technology for precision milling operations. However, the concurrence of several input parameters along with the stochastic nature of this technology leads to a complex process control, which requires a work focused in process modelling. This research work introduces a model to predict the kerf shape in AWJ slot milling in Aluminium 7075-T651 in terms of four important process parameters: the pressure, the abrasive flow rate, the stand-off distance and the traverse feed rate. A hybrid evolutionary approach was employed for kerf shape modelling. This technique allowed characterizing the profile through two parameters: the maximum cutting depth and the full width at half maximum. On the other hand, based on ANOVA and regression techniques, these two parameters were also modelled as a function of process parameters. Combination of both models resulted in an adequate strategy to predict the kerf shape for different machining conditions.

  1. A study on practical use of underwater abrasive water jet cutting

    Science.gov (United States)

    Yamaguchi, Hitoshi; Demura, Kenji

    1993-09-01

    The practicality of underwater abrasive water jet cutting technology was studied in experiments. A study of abrasives in slurried form showed that optimum polymer concentration can be selected to suit underwater conditions. For the long-distance transport of slurry from the ocean surface to the ocean floor, a direct supply system by hose proved to be practical. This system takes advantage of the insolubility of the slurry in water due to a difference in specific gravity. For cutting thick steel plate at great ocean depths, a simulation with a pressurized container revealed the requirements for actual cutting. Confirmation of remote cutting operations will become the most important technology in field applications. Underwater sound vibration characteristics were found to change significantly in direct response to modifications in cutting conditions. This will be important basic data to develop an effective sensoring method.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  3. Structure and Abrasive Wear of Composite HSS M2/WC Coating

    Directory of Open Access Journals (Sweden)

    S. F. Gnyusov

    2012-01-01

    Full Text Available Features of phase-structure formation and abrasive wear resistance of composite coatings “WC-M2 steel” worn against tungsten monocarbide have been investigated. It was established that adding 20 wt.% WC to the deposited powder mixture leads to the increase in M6C carbide content. These carbides show a multimodal size distribution consisting of ~5.9 μm eutectic carbides along the grain boundaries, ~0.25 μm carbides dispersed inside the grains. Also a greater amount of metastable austenite (~88 vol.% is found. The high abrasive wear resistance of these coatings is provided by γ→α′-martensitic transformation and multimodal size distribution of reinforcing particles.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    OpenAIRE

    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...

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

    Directory of Open Access Journals (Sweden)

    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.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    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.

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

    Science.gov (United States)

    Arami, Sakineh; Tabatabae, Masoume Hasani; Namdar, Seyedeh Fatemeh; Chiniforush, Nasim

    2014-03-01

    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.

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

    OpenAIRE

    Hlaváček, P. (Petr); Brumek, J.; Horsák, L.

    2012-01-01

    The paper provides a general introduction to methods of measurement of residual stresses on railway wheels. Determination of residual stress distribution is necessary for the prediction of wheel service life and possible catastrophic failure. Therefore experimental section is devoted to residual stress measurement using strain gauges according to standard EN 13262 + A1. During measurement, several segments of tested wheel were cut by abrasive water jet to detect changes of residual stresses o...

  13. Performance analysis of cutting graphite-epoxy composite using a 90,000psi abrasive waterjet

    Science.gov (United States)

    Choppali, Aiswarya

    Graphite-epoxy composites are being widely used in many aerospace and structural applications because of their properties: which include lighter weight, higher strength to weight ratio and a greater flexibility in design. However, the inherent anisotropy of these composites makes it difficult to machine them using conventional methods. To overcome the major issues that develop with conventional machining such as fiber pull out, delamination, heat generation and high tooling costs, an effort is herein made to study abrasive waterjet machining of composites. An abrasive waterjet is used to cut 1" thick graphite epoxy composites based on baseline data obtained from the cutting of ¼" thick material. The objective of this project is to study the surface roughness of the cut surface with a focus on demonstrating the benefits of using higher pressures for cutting composites. The effects of major cutting parameters: jet pressure, traverse speed, abrasive feed rate and cutting head size are studied at different levels. Statistical analysis of the experimental data provides an understanding of the effect of the process parameters on surface roughness. Additionally, the effect of these parameters on the taper angle of the cut is studied. The data is analyzed to obtain a set of process parameters that optimize the cutting of 1" thick graphite-epoxy composite. The statistical analysis is used to validate the experimental data. Costs involved in the cutting process are investigated in term of abrasive consumed to better understand and illustrate the practical benefits of using higher pressures. It is demonstrated that, as pressure increased, ultra-high pressure waterjets produced a better surface quality at a faster traverse rate with lower costs.

  14. Elimination of intracanal metallic obstructions by abrasion using an operational microscope and ultrasonics.

    Science.gov (United States)

    Nehme, W B

    2001-05-01

    Intracanal metallic obstructions that block any further treatment often prevent the clinician from achieving total cleanliness of the root canal system. For the retrieval of these obstructions, most of the methods described suggest creating and enlarging a space around the obstruction to loosen it before its retrieval. This article describes a technique that consists of mechanical abrasion of the obstruction without altering canal walls by using an operational microscope and ultrasonic spreader.

  15. Abrasion-Resistant Aluminized-Coated Aramid Fabrics for Manufacture of Firefighters’ Protective Clothing

    Science.gov (United States)

    1985-05-01

    and radiacion are also produced at the cathode surface and may profoundly influence the quality of the substrate coating. These include secondary...14,265-378 (1979). Assink, R.A. Abrasion resistant polymer reflectors for solar applications. Solar Energy Mater vol. 3:263-75, (1980). Audet, N.F. Visor... solar reflectors. Solar Energy Mater vol. 3: No.1-2,277-83,(1981). *Gubareff, G.G., J.E. Janssen, and R.H. Torborg. Thermal radiation properties survey

  16. The influence of varnish and high fluoride on erosion and abrasion in a laboratory investigation.

    Science.gov (United States)

    Sar Sancakli, H; Austin, R S; Al-Saqabi, F; Moazzez, R; Bartlett, D

    2015-03-01

    The aim of this study was to investigate the potential of concentrated fluoride varnishes to reduce enamel loss from repeated cycles of citric acid erosion and toothbrush abrasion in vitro. Polished human enamel samples were exposed to fluoride varnishes: Bifluorid10® (NaF&CaF2- 45,200 ppmF), Duraphat® (NaF 22,600 ppmF), Fluor-Protector® (difluorsilane 1000 ppmF) and a control coating of copal ether varnish (0 ppmF) group and a deionized water group. For each group of 16 samples, nine cycles of erosion and nine cycles of erosion-abrasion [1 cycle=erosion (0.3% citric acid, pH 3.2, 5 min)+artificial saliva (1 h, pH 7.0)+abrasion (120 linear strokes in artificial saliva from Oral B medium soft brushes 300 g loading]. The change in the enamel surface was evaluated using optical profilometry. Duraphat® and Bifluorid10® applications had a median (IQR) step height of 4.21 um (1.59) and 5.01 um (1.02). This was statistically significantly less than Fluor-Protector® 6.83 um (1.25), copal ether 7.22 um (1.97) and water 7.39 um (1.96) (pfluoride in a range of single-application topical varnishes was effective in reducing enamel wear from erosion and erosion-abrasion in this laboratory study. © 2015 Australian Dental Association.

  17. Abrasive Wear Resistance of Tool Steels Evaluated by the Pin-on-Disc Testing

    Science.gov (United States)

    Bressan, José Divo; Schopf, Roberto Alexandre

    2011-05-01

    Present work examines tool steels abrasion wear resistance and the abrasion mechanisms which are one main contributor to failure of tooling in metal forming industry. Tooling used in cutting and metal forming processes without lubrication fails due to this type of wear. In the workshop and engineering practice, it is common to relate wear resistance as function of material hardness only. However, there are others parameters which influences wear such as: fracture toughness, type of crystalline structure and the occurrence of hard precipitate in the metallic matrix and also its nature. In the present investigation, the wear mechanisms acting in tool steels were analyzed and, by normalized tests, wear resistance performance of nine different types of tool steels were evaluated by pin-on-disc testing. Conventional tool steels commonly used in tooling such as AISI H13 and AISI A2 were compared in relation to tool steels fabricated by sintering process such as Crucible CPM 3V, CPM 9V and M4 steels. Friction and wear testing were carried out in a pin-on-disc automated equipment which pin was tool steel and the counter-face was a abrasive disc of silicon carbide. Normal load of 5 N, sliding velocity of 0.45 m/s, total sliding distance of 3000 m and room temperature were employed. The wear rate was calculated by the Archard's equation and from the plotted graphs of pin cumulated volume loss versus sliding distance. Specimens were appropriately heat treated by quenching and three tempering cycles. Percentage of alloying elements, metallographic analyses of microstructure and Vickers microhardness of specimens were performed, analyzed and correlated with wear rate. The work is concluded by the presentation of a rank of tool steel wear rate, comparing the different tool steel abrasion wear resistance: the best tool steel wear resistance evaluated was the Crucible CPM 9V steel.

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

    OpenAIRE

    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...

  19. High abrasion resistance coating materials from organic/inorganic hybrid materials produced by the sol-gel method

    OpenAIRE

    1990-01-01

    A series of new high abrasion resistance coating materials have been prepared utilizing organic/inorganic hybrid materials formed by cohydrolyzing a metal alkoxide sol (e.g. silicon, aluminum, titanium, or zirconium metal alkoxide sol) with one or more bis(trialkoxysilane-containing) organic components or related functionalized species. These hybrid materials show optical clarity and improve the abrasion resistance of polymer substrates when applied as coatings and cured on such substrates.

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

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Institute of Scientific and Technical Information of China (English)

    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.

  2. Portable mixed abrasive water jet equipment for rescue in high gas mine shaft

    Institute of Scientific and Technical Information of China (English)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Rapid manufacturing of SiC molds with micro-sized holes using abrasive water jet

    Institute of Scientific and Technical Information of China (English)

    Bo-Sung SHIN; Kang-Su PARK; Yeon-Kyoung BAHK; Sun-Ki PARK; Jung-Han LEE; Jeung-Sang GO; Myung-Chang KANG; Chae-Moon LEE

    2009-01-01

    Silicon carbide (SIC) is highly wear resistant with good mechanical properties, including high temperature strength, excellent chemical resistance, and high thermal conductivity and thermal shock resistance. SiC molds, which can be produced with diverse microstructural features, are now widely used in glass molding owing to their excellent characteristics, and also have potential applicability in IT industries. SiC molds are traditionally fabricated by silicon micromachining or dicing. The fabrication cost of silicon micromachining is very high, however, because several expensive masks are needed. Furthermore, the fabrication time is very long. Meanwhile, it is difficult to make micro-patterned molds with arbitrary shapes using dicing saws. Abrasive water jet (AWJ) is widely applied to cut and drill very brittle, soft and fibrous materials. It offers high energy density, the absence of a heat affected zone(HAZ), high performance, and an environment friendly process. In spite of these advantages, micro-hole drilling via conventional AWJ processing suffers from notable shortcomings. We proposed a new abrasive supplying method of AWJ. The proposed method reduces frosting phenomena, and provides micro-machining of AWJ. The characteristics of a hole machined was investigated by the proposed AWJ process according to the ratio of water and abrasives. With the optimal experimental conditions, 3 × 3 array SiC molds with the diameter of 700 μm and depth of 900 μm were successfully manufactured.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, Joachim [Central Facility for Electron Microscopy (GFE), RWTH Aachen University, 52056 Aachen (Germany)]. E-mail: mayer@gfe.rwth-aachen.de; Engelhorn, Robert [Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, 52056 Aachen (Germany); Bot, Rosemarie [Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, 52056 Aachen (Germany); Weirich, Thomas [Central Facility for Electron Microscopy (GFE), RWTH Aachen University, 52056 Aachen (Germany); Herwartz, Cleo [Central Facility for Electron Microscopy (GFE), RWTH Aachen University, 52056 Aachen (Germany); Klocke, Fritz [Laboratory for Machine Tools and Production Engineering (WZL), RWTH Aachen University, 52056 Aachen (Germany)

    2006-08-15

    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 321{sup TM}) 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.

  7. An investigation on surface roughness of granite machined by abrasive waterjet

    Indian Academy of Sciences (India)

    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. Evaluation of planarization performance for a novel alkaline copper slurry under a low abrasive concentration

    Science.gov (United States)

    Mengting, Jiang; Yuling, Liu; Haobo, Yuan; Guodong, Chen; Weijuan, Liu

    2014-11-01

    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 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.

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

    Science.gov (United States)

    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. Improved Soft Abrasive Flow Finishing Method Based on Turbulent Kinetic Energy Enhancing

    Science.gov (United States)

    LI, Jun; JI, Shiming; TAN, Dapeng

    2017-03-01

    Soft abrasive flow(SAF) finishing can process the irregular geometric surfaces, but with the matter of low processing efficiency. To address the issue, an improved SAF finishing method based on turbulent kinetic energy enhancing is proposed. A constrained flow passage with serration cross-section is constructed to increase the turbulence intensity. Taking the constrained flow passage as the objective, a two-phase fluid dynamic model is set up by using particle trajectory model and standard k-ɛ turbulence model, and the flow field characteristics of the flow passage are acquired. The numerical results show that the serration flow passage can enhance the turbulence intensity, uniform the particles distribution, and increase the particle concentration near the bottom wall. The observation results by particle image velocimetry(PIV) show that the internal vortex structures are formed in flow passage, and the abrasive flow takes on turbulence concentrating phenomenon in near-wall region. The finishing experiments prove that the proposed method can obtain better surface uniformity, and the processing efficiency can be improved more 35%. This research provides an abrasive flow modeling method to reveal the particle motion regulars, and can offer references to the technical optimization of fluid-based precision processing.

  11. Investigation of the Effects of Machining Parameters on Material Removal Rate in Abrasive Waterjet Turning

    Directory of Open Access Journals (Sweden)

    Iman Zohourkari

    2014-05-01

    Full Text Available The effects of the main operational machining parameters on the material removal rate (MRR in abrasive waterjet turning (AWJT are presented in this paper using a statistical approach. The five most common machining parameters such as water pressure, abrasive mass flow rate, cutting head traverse speed, workpiece rotational speed, and depth of cut have been put into a five-level central composite rotatable experimental design (CCRD. The main effects of parameters and the interaction among them were analyzed by means of the analysis of variance (ANOVA and the response surfaces for MRR were obtained fitting a second-order polynomial function. It has been found that depth of cut and cutting head traverse speed are the most influential parameters, whereas the rotational speed is insignificant. In addition, the investigations show that interactions between traverse speed and pressure, abrasive mass flow rate and depth of cut, and pressure and depth of cut are significant on MRR. This result advances the AWJT state of the art. A complete model discussion has been reported drawing interesting considerations on the AWJT process characterising phenomena, where parameters interactions play a fundamental role.

  12. Ergonomics of abrasive blasting: a comparison of high pressure water and steel shot.

    Science.gov (United States)

    Rosenberg, Beth; Yuan, Lu; Fulmer, Scott

    2006-09-01

    Abrasive blasting with silica sand has long been associated with silicosis. Alternatives to sand are being used increasingly. While NIOSH has done extensive investigations of the respiratory effects of the substitutes for sand, the ergonomic effects of the substitutes have not been examined. Too often, hazards are shifted, and technologies that might save workers' lungs could do so at the expense of their musculoskeletal systems. Hence, the objective of this study was to examine the ergonomic effects of alternatives to sand. Multiple methods, both qualitative and quantitative, were used to yield numerous kinds of data for the analysis of exposures to abrasive blasters. PATH, a method for quantifying ergonomic exposure in non-routine work, was combined with interviews with workers, biomechanical modeling and noise level readings to assess the ergonomics of two abrasive blasting operations: high-pressure water and steel shot. Advantages and disadvantages of each medium are discussed. High-pressure water was slightly less ergonomically stressful, environmentally cleaner, much quieter and less dusty that steel shot, and it was reported to be slower on those tasks where both media could be used.

  13. Effect of Pearlite Interlamellar Spacing on Predominant Abrasive Wear Mechanism of Fully Pearlitic Steel

    Institute of Scientific and Technical Information of China (English)

    J.Ahmadi; M.Monirvaghefi; M.Salehi; B.Niroumand

    2004-01-01

    The aim of this investigation was the determination of the predominant wear mechanism an three-body abrasion of fully pearlitic low ahoy steel. Furthermore. the effect of pearlite interlamellar spacing on wear behavior was investigated, For this purpase, the samples were subjected to the different heat treating to artainthg different interlamellar spacing. Mechanical properties such as hardness, yield strength, tensile strength, elongation, and impact toughness were evaluated. Three body abrasion tests were conducted under ASTM standard condition using a rubber wheel abrasion test apparatus. Abraded surface and wear debris were investigated by light optical microscopy and scanning electron microscopy. The results showed that wear resistance of fully pearlitic steel depended to pearlite interlamellar spacing the and lower spacing has the greater wear realstance, so it may be due to subsurface work hardening and interlamellar spacing and cernentite in fine and/or coarse pearlite, thai influence on surface destruction during wear. Although during wear process the several mechanisms play roles, but study of surface and debris shows that with decreasing interlamellar spacing, the predominant mechanism wear changed front ploughing to cuttthg mode.

  14. Effect of abrasive surface roughening on the secondary yield of various metals

    Science.gov (United States)

    Graves, Timothy

    2007-11-01

    The secondary electron yield of metallic conductors plays a critical role in the development of multipactor discharges. These discharges require a secondary yield greater than unity at the appropriate energy level for sustained breakdown. By reducing the secondary yield below unity in the necessary energy range, multipactor and multipactor-induced glow discharges can be eliminated. Surface roughening has been shown to successfully lower the secondary yield to below unity (ref. 1). In addition, abrasive bead blasting has been shown to effectively reduce the secondary yield of copper surfaces while preserving voltage breakdown characteristics (ref. 2). This study investigates the effect of abrasive surface roughening on the secondary yield of materials such as copper, aluminum, and stainless steel. In addition to measuring the change in the secondary yield as a function of abrasive particle size, the multipactor resistance and voltage breakdown characteristics are investigated. In addition, the effect of vacuum conditioning via multipactor and rf plasma cleaning on the roughened surfaces will be discussed. Ref. 1. H. Bruining. Physics and Applications of Secondary Electron Emission. McGraw-Hill, NY, 1954. Ref. 2. T. P. Graves, Ph.D. Thesis, MIT. 2007

  15. Effect of Pearlite Interlamellar Spacing on Predominant Abrasive Wear Mechanism of Fully Pearlitic Steel

    Institute of Scientific and Technical Information of China (English)

    J. Ahmadi; M. Monirvaghefi; M. Salehi; B. Niroumand

    2004-01-01

    The aim of this investigation was the determination of the predominant wear mechanism on three-body abrasion of fully pearlitic low alloy steel. Furthermore, the effect of pearlite interlamellar spacing on wear behavior was investigated.For this purpose, the samples were subjected to the different heat treating to attaining different interlamellar spacing.Mechanical properties such as hardness, yield strength, tensile strength, elongation, and impact toughness were evaluated.Three body abrasion tests were conducted under ASTM standard condition using a rubber wheel abrasion test apparatus.Abraded surface and wear debris were investigated by light optical microscopy and scanning electron microscopy.The results showed that wear resistance of fully pearlitic steel depended to pearlite interlamellar spacing the and lower spacing has the greater wear resistance, so it may be due to subsurface work hardening and interlamellar spacing and cementite in fine and/or coarse pearlite, that influence on surface destruction during wear. Although during wear process the several mechanisms play roles, but study of surface and debris shows that with decreasing interlamellar spacing, the predominant mechanism wear changed from ploughing to cutting mode.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    Institute of Scientific and Technical Information of China (English)

    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. Experimental Study on Layered Ice Bonded Abrasive Polishing of Glass-ceramics

    Directory of Open Access Journals (Sweden)

    Yuli SUN

    2014-12-01

    Full Text Available Layered ice bonded abrasive tools (LIBAT is a new kind of one which not only has the ability of lapping and polishing but also has the effect of self-dressing. In this paper, two kinds of layered ice bonded abrasive tools were designed and manufactured. Experimental studies on layered ice bonded abrasive (LIBA polishing of glass-ceramics were conducted. The results show that the surface topography of glass-ceramics polished by micro α-Al2O3-nano α-Al2O3 LIBAT is better than that of polished by micro α-Al2O3-nano SiO2 LIBAT. The surface roughness Sa of glass-ceramics polished by the two kinds of LIBAT is at the nanometer scale. The reasons of this phenomenon were analyzed. The experimental results illustrate that the LIBAT shows good effect and can be used in production practice. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6149

  19. Microstructure and Abrasive Wear Performance of Ni-Wc Composite Microwave Clad

    Science.gov (United States)

    Bansal, Amit; Zafar, Sunny; Sharma, Apurbba Kumar

    2015-10-01

    In the present work, Ni-WC powder was deposited on mild steel substrate to develop clads through microwave hybrid heating technique. The cladding trials were carried out in an industrial microwave applicator at 1.1 kW for 540 s. The Ni-WC composite clads were characterized for microstructure and abrasive wear performance through combination of x-ray diffraction, electron and optical microscopy, microhardness, and wear tests. Phase analysis of the Ni-WC clad indicated the presence of stable carbides such as WC, W2C, Ni2W4C, and Fe6W6C. The microstructure study of the clad layer revealed the presence of a uniformly distributed interlocked WC-based reinforcement embedded in the Ni-based matrix. The average Vicker's microhardness in the clad layer was observed to be 1028 ± 90 HV, which was approximately three times the microhardness of the substrate. Abrasive wear resistance of the microwave clads was superior to the MS substrate. Abrasion was the main wear mechanism in the Ni-WC clads and the substrate samples. However, the presence of WC-based reinforcement in the composite clads reduced microcutting, resulting in enhanced wear resistance.

  20. The surface quality of AWJ cut parts as a function of abrasive material reusing rate

    Science.gov (United States)

    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).

  1. Rock Cutting Depth Model Based on Kinetic Energy of Abrasive Waterjet

    Science.gov (United States)

    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.

  2. Coupling behavior between adhesive and abrasive wear mechanism of aero-hydraulic spool valves

    Institute of Scientific and Technical Information of China (English)

    Chen Yunxia; Gong Wenjun; Kang Rui

    2016-01-01

    Leakage due to wear is one of the main failure modes of aero-hydraulic spool valves. This paper established a practical coupling wear model for aero-hydraulic spool valves based on dynamic system modelling theory. Firstly, the experiment for wear mechanism verification proved that adhesive wear and abrasive wear did coexist during the working process of spool valves. Sec-ondly coupling behavior of each wear mechanism was characterized by analyzing actual time-variation of model parameters during wear evolution process. Meanwhile, Archard model and three-body abrasive wear model were utilized for adhesive wear and abrasive wear, respectively. Furthermore, their coupling wear model was established by calculating the actual wear volume. Finally, from the result of formal test, all the required parameters for our model were obtained. The relative error between model prediction and data of pre-test was also presented to verify the accuracy of model, which demonstrated that our model was useful for providing accurate prediction of spool valve’s wear life.

  3. Erosion and abrasion on dental structures undergoing at-home bleaching

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    Sagil James

    2014-01-01

    Full Text Available 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 nanoscale material removal. The VANILA process are conducted such that the tool tip does not directly contact the workpiece. The level of precision and quality of the machined features in a nanomachining process is contingent on the tool wear which is inevitable. Initial experimental studies have demonstrated reduced tool wear in the VANILA process as compared to indentation process in which the tool directly contacts the workpiece surface. In this study, the tool wear rate during the VANILA process is analytically modeled considering impacts of abrasive grains on the tool tip surface. Experiments are conducted using several tools in order to validate the predictions of the theoretical model. It is seen that the model is capable of accurately predicting the tool wear rate within 10% deviation.

  5. Effects of hybrid composition of LCP and glass fibres on abrasive wear of reinforced LLDPE

    Indian Academy of Sciences (India)

    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.

  6. INFLUENCE OF REFRACTORY FILLERS ON THE PROCESS OF COMPOSITE BRAZING OF DIAMOND-ABRASIVE TOOLS

    Directory of Open Access Journals (Sweden)

    Kozachenko A. D.

    2015-04-01

    Full Text Available Brazes with increased viscosity are needed for brazing of abrasive diamond tools with working surface of complex contoured shape. It’s known that high viscosity is a property of composite brazes consisting of fusible matrix and refractory filler that is not melting during brazing. Goal of the work is to research the influence of refractory fillers on the process of composite brazing of diamond-abrasive tools and on that basis discover the optimal composition of braze. Composite brazes Sn-Cu-Co were researched in the work. It is determined that at least 26-28% (by mass of cobalt powder should be included in brazes for giving the braze Sn-Cu-Co necessary viscosity and for creation of uniform diamond-comprising layers with thickness up to 2.5 mm on the vertical layers and sharp edges of tools. It is determined that solid-state sintering of powders on the initial stage of heating the composite braze leads to emerging of internal stresses and forming cracks. Inert additions that prevent solid-state sintering should be include in braze to prevent cracking. Optimal inert addition for brazes Sn-Cu-Co is the tungsten powder. Minimum content of tungsten needed to prevent cracking is 6% (by mass. Optimal content of components in composition braze for brazing shaped diamond-abrasive tools is (% by mass: 30 Co, 20 Sn, 43 Cu, 7 W

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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

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

    Directory of Open Access Journals (Sweden)

    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.

  10. Tooth length and incisal wear and growth in guinea pigs (Cavia porcellus) fed diets of different abrasiveness.

    Science.gov (United States)

    Müller, J; Clauss, M; Codron, D; Schulz, E; Hummel, J; Kircher, P; Hatt, J-M

    2015-06-01

    Dental diseases are among the most important reasons for presenting guinea pigs (Cavia porcellus) and other rodents to veterinary clinics, but the aetiopathology of this disease complex is unclear. Clinicians tend to believe that the ever-growing teeth of rabbits and rodents have a constant growth that needs to be worn down by the mastication of an appropriate diet. In this study, we tested the effect of four different pelleted diets of increasing abrasiveness [due to both internal (phytoliths) and external abrasives (sand)] or whole grass hay fed for 2 weeks each in random order to 16 guinea pigs on incisor growth and wear, and tooth length of incisors and cheek teeth. There was a positive correlation between wear and growth of incisors. Tooth lengths depended both on internal and external abrasives, but only upper incisors were additionally affected by the feeding of whole hay. Diet effects were most prominent in anterior cheek teeth, in particular M1 and m1. Cheek tooth angle did not become shallower with decreasing diet abrasiveness, suggesting that a lack of dietary abrasiveness does not cause the typical 'bridge formation' of anterior cheek teeth frequently observed in guinea pigs. The findings suggest that other factors than diet abrasiveness, such as mineral imbalances and in particular hereditary malocclusion, are more likely causes for dental problems observed in this species. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

  11. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    Science.gov (United States)

    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 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

    Energy Technology Data Exchange (ETDEWEB)

    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

    Directory of Open Access Journals (Sweden)

    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. Efecto del consumo de linaza en el perfil lipidico, el control del cancer y como terapia de reemplazo hormonal en la menopausia: una revision sistematica de ensayos clinicos aleatorizados

    National Research Council Canada - National Science Library

    Molina Castano, Carlos Federico; Ruiz Pineda, Adriana Marcela; Lopez Marin, Beatriz Estella; Arango Alzate, Catalina Maria; Gaviria Gomez, Berta Lucia

    2011-01-01

    ... andropausia. Materiales y metodos: se realizo una revision sistematica de ensayos clinicos aleatorizados que examinaron los efectos del consumo de linaza sobre el peso corporal, la concentracion de lipidos sanguineos, el control...

  15. [From classification medicine to clinical medicine (the end of the XVIII century--1870s). Communication 2. The first stage of clinical medicine development: introduction of the method of clinico-anatomic correlations].

    Science.gov (United States)

    2011-01-01

    The first stage of clinical medicine development is analysed which covers the period from early 1800s to middle 1870s. Considered are basic research achievements associated with introduction of the method of clinico-anatomic correlations into practical medicine.

  16. Disturbios da olfacao: estudo retrospectivo

    Directory of Open Access Journals (Sweden)

    Luciano Lobato Gregorio

    2014-01-01

    Full Text Available Introdução: O olfato, fenômeno subjetivo de grande importância, é pouco compreendido e estudado no ser humano. Médicos com maior conhecimento sobre os distúrbios desse sentido tendem a considerar a doença mais importante e manejar melhor o diagnóstico e o tratamento. Objetivo: Descrever a amostra dos pacientes com queixa principal de distúrbios do olfato e mostrar a experiência do serviço no manejo e tratamento. Delineamento: Estudo retrospectivo de coorte histórica com corte transversal. Materiais e métodos: Descrição da amostra e avaliação de resposta ao tratamento de pacientes com queixa principal de hiposmia ou anosmia atendidos no ambulatório de Rinologia no período de janeiro de 2005 a outubro de 2011. Resultados: Dos 38 pacientes com distúrbio da olfação, 68,4% dos pacientes apresentaram queixa de hiposmia e 31,5% de anosmia, com duração média de 30,8 meses. Os diagnósticos etiológicos principais foram idiopática (31,5%, rinopatia alérgica (28,9% e RSC com pólipos (10,5%. As respostas ao tratamento com corticosteroide tópico e ácido alfa-lipoico foram variáveis, assim como na literatura. Conclusão: Maior importância deve ser dada aos distúrbios do olfato na prática do otorrinolaringologista, uma vez que o diagnóstico diferencial é amplo e pode trazer grande morbidade ao paciente, com impacto na sua qualidade de vida.

  17. Hiperprolactinemia : expressao clinica, hormonal e radiologica em pacientes femininas, antes e durante o tratamento clinico

    OpenAIRE

    Elaine Sangali Mallmann

    1993-01-01

    A hiperprolactinemia constitui-se num achado laboratorial que quando resultante de secreção inapropriada, pode indicar tanto um processo patológico orgânico, como uma desordem funcional reversível. Representa o distúrbio hipofisário mais frequentemente encontrado na prática clinica e constitui um dos aspectos mais importantes no estudo da endocrinologia da reprodução. As hiperprolactinemias de causas não fisiológicas são secundárias mais frequentemente a efeito farmacológico, presença de tumo...

  18. Para-clinico-pathological observations of insidious incidence of canine hepatozoonosis from a mongrel dog: a case report.

    Science.gov (United States)

    Kaur, Paramjit; Deshmukh, S; Singh, Rajsukhbir; Bansal, B K; Randhawa, C S; Singla, L D

    2012-04-01

    A rare case of canine hepatozoonosis in a mongrel dog with para-clinico-pathological observations has been reported. The study included detailed haemato-biochemical changes at two stages, i.e. before treatment and after treatment with adopted therapy. Before therapy, blood picture revealed normocytic hypochromic anaemia and neutrophilic leucocytosis with variable counts of platelets. Thirty-seven percent of neutrophils were found infected with gametocytes of Hepatozoon canis. Following treatment, further decrease in haemoglobin value with a relative increase in lymphocyte count was seen. Biochemically, increase in alkaline phosphatase, blood urea nitrogen and creatinine levels along with hyperproteinemia was seen. The 14 days chemotherapy did not bring a respite for the dog and the level of parasitaemia was 33% after the treatment. The alkaline phosphatase and creatinine level further rose up following therapy with sulphadiazine and clindamycin. Continual study is required to explain the best possible therapeutic combination to deal H. canis.

  19. Primary high grade sarcoma of the specialised prostatic stroma: a case report with clinico-pathological considerations.

    Science.gov (United States)

    Fraggetta, F; Pepe, P; Giunta, M L; Aragona, F

    2008-12-01

    Malignant tumours of the prostate other than carcinomas are rare. One such malignant tumours arising from the specialised stromal tissue of the prostate is stromal prostatic sarcoma (namely low-grade and high-grade). Herein, we report the clinico-pathological features of a high grade stromal sarcoma of the prostate occurring in a 65-year-old man who presented for urinary obstructive symptoms. The clinical picture suggested a benign prostatic hyperplasia, and surgery consisting in a transcapsular adenomectomy was performed. Following a pathological diagnosis of high grade prostatic stromal sarcoma, a radical cystoprostatectomy and bilateral pelvic node dissection was performed showing residual high grade stromal sarcoma of the prostate and incidental in situ urothelial carcinoma of the bladder. No further medical treatments were planned. One year after surgery the patient is well with no evidence of local disease or distant metastases.

  20. Chronic lymphocytic leukemia in the elderly: clinico-biological features, outcomes, and proposal of a prognostic model.

    Science.gov (United States)

    Baumann, Tycho; Delgado, Julio; Santacruz, Rodrigo; Martínez-Trillos, Alejandra; Royo, Cristina; Navarro, Alba; Pinyol, Magda; Rozman, María; Pereira, Arturo; Villamor, Neus; Aymerich, Marta; López, Cristina; Carrió, Anna; Montserrat, Emili

    2014-10-01

    We investigated the clinico-biological features, outcomes, and prognosis of 949 patients with chronic lymphocytic leukemia according to age. No biological differences (cytogenetics by fluorescent in situ hybridization, IGHV, ZAP-70, CD38, NOTCH1, SF3B1) were found across age groups. Elderly patients (>70 years; n=367) presented more frequently with advanced disease (Binet C/Rai III-IV: 10/12% versus 5/5%; P4; hazard ratio 2.2, P<0.001) and response (treatment failure versus response: hazard ratio 1.60, P<0.04) were the most important prognostic factors for overall survival. In conclusion, in our series, elderly patients with chronic lymphocytic leukemia did not present with any biological features distinct from those of younger patients, but did have a poorer clinical outcome. This study highlights the importance of comprehensive medical care, achieving response to therapy, and specific management strategies for elderly patients with chronic lymphocytic leukemia.

  1. Effect of Bioactive Glass air Abrasion on Shear Bond Strength of Two Adhesive Resins to Decalcified Enamel

    Science.gov (United States)

    Eshghi, Alireza; Khoroushi, Maryam; Rezvani, Alireza

    2014-01-01

    Objective: 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. Materials and Methods: 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. Results: 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. Conclusion: 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. PMID:25628694

  2. Effect of Bioactive Glass air Abrasion on Shear Bond Strength of Two Adhesive Resins to Decalcified Enamel.

    Directory of Open Access Journals (Sweden)

    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.

  3. RUNX1 mutations in acute myeloid leukemia are associated with distinct clinico-pathologic and genetic features.

    Science.gov (United States)

    Gaidzik, V I; Teleanu, V; Papaemmanuil, E; Weber, D; Paschka, P; Hahn, J; Wallrabenstein, T; Kolbinger, B; Köhne, C H; Horst, H A; Brossart, P; Held, G; Kündgen, A; Ringhoffer, M; Götze, K; Rummel, M; Gerstung, M; Campbell, P; Kraus, J M; Kestler, H A; Thol, F; Heuser, M; Schlegelberger, B; Ganser, A; Bullinger, L; Schlenk, R F; Döhner, K; Döhner, H

    2016-11-01

    We evaluated the frequency, genetic architecture, clinico-pathologic features and prognostic impact of RUNX1 mutations in 2439 adult patients with newly-diagnosed acute myeloid leukemia (AML). RUNX1 mutations were found in 245 of 2439 (10%) patients; were almost mutually exclusive of AML with recurrent genetic abnormalities; and they co-occurred with a complex pattern of gene mutations, frequently involving mutations in epigenetic modifiers (ASXL1, IDH2, KMT2A, EZH2), components of the spliceosome complex (SRSF2, SF3B1) and STAG2, PHF6, BCOR. RUNX1 mutations were associated with older age (16-59 years: 8.5%; ⩾60 years: 15.1%), male gender, more immature morphology and secondary AML evolving from myelodysplastic syndrome. In univariable analyses, RUNX1 mutations were associated with inferior event-free (EFS, P<0.0001), relapse-free (RFS, P=0.0007) and overall survival (OS, P<0.0001) in all patients, remaining significant when age was considered. In multivariable analysis, RUNX1 mutations predicted for inferior EFS (P=0.01). The effect of co-mutation varied by partner gene, where patients with the secondary genotypes RUNX1(mut)/ASXL1(mut) (OS, P=0.004), RUNX1(mut)/SRSF2(mut) (OS, P=0.007) and RUNX1(mut)/PHF6(mut) (OS, P=0.03) did significantly worse, whereas patients with the genotype RUNX1(mut)/IDH2(mut) (OS, P=0.04) had a better outcome. In conclusion, RUNX1-mutated AML is associated with a complex mutation cluster and is correlated with distinct clinico-pathologic features and inferior prognosis.

  4. Triggers, risk factors and clinico-pathological features of urticaria in dogs - a prospective observational study of 24 cases.

    Science.gov (United States)

    Rostaher, Ana; Hofer-Inteeworn, Natalie; Kümmerle-Fraune, Claudia; Fischer, Nina Maria; Favrot, Claude

    2017-02-01

    Urticaria and anaphylaxis are frequently encountered in veterinary practice, but little is known about the causes and relative frequencies of these reactions. This study was designed to improve current knowledge on the triggers, risk factors and clinico-pathological features of urticaria. Twenty four dogs with signs of urticaria with or without anaphylaxis. The study included dogs with cutaneous immediate-type hypersensitivity reactions. The cases were grouped by clinical severity into either an urticaria or an anaphylaxis group. All treatments and diagnostic tests (haematology, biochemical profile, allergy investigation) were recorded. A causality algorithm for urticaria and anaphylaxis (ALUA) was designed to determine the probability of the identified triggers and cofactors. Disease incidence, breed, age and gender predispositions were evaluated statistically. Sixteen of 24 urticaria cases were associated with anaphylaxis whilst 8 of 24 were confined to the skin. The annual hospital incidence was 0.12%. Females seemed to be over-represented (2.4:1) and most of the dog breeds were pure breed (22 of 24), with Rhodesian ridgeback, boxer, beagle, Jack Russell terrier, French bulldog and Vizslas over-represented. In addition to skin lesions, the most frequently and severely affected organ systems were the gastrointestinal and cardiovascular systems. The predominant blood abnormalities were elevated lipase and alanine aminotransferase values. Insects, food and drugs were the most commonly identified triggers. To the best of our knowledge, this is the first study describing the trigger factors and clinico-pathological features of dogs with urticaria in veterinary medicine. Insects, food and drugs were the most frequently detected triggers. © 2016 ESVD and ACVD.

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

    Directory of Open Access Journals (Sweden)

    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.

  6. The influence of aluminum and carbon on the abrasion resistance of high manganese steels

    Science.gov (United States)

    Buckholz, Samuel August

    Abrasive wear testing of lightweight, austenitic Fe-Mn-Al-C cast steel has been performed in accordance with ASTM G65 using a dry sand, rubber wheel, abrasion testing apparatus. Testing was conducted on a series of Fe-30Mn-XAl-YC-1Si-0.5Mo chemistries containing aluminum levels from 2.9 to 9.5 wt.% and carbon levels from 0.9 to 1.83 wt.%. Solution treated materials having an austenitic microstructure produced the highest wear resistance. Wear resistance decreased with higher aluminum, lower carbon, and higher hardness after age hardening. In the solution treated condition the wear rate was a strong function of the aluminum to carbon ratio and the wear rate increased with a parabolic dependence on the Al/C ratio, which ranged from 1.8 to 10.2. Examination of the surface wear scar revealed a mechanism of plowing during abrasion testing and this method of material removal is sensitive to work hardening rate. Work hardening behavior was determined from tensile tests and also decreased with increasing Al/C ratio and after aging hardening. The loss of wear resistance is related to short range ordering of Al and C in the solution treated materials and kappa-carbide precipitation in age hardened materials and both contribute to planar slip and lower work hardening rates. A high carbon tool steel (W1) and a bainitic low alloy steel (SAE 8620) were also tested for comparison. A lightweight steel containing 6.5 wt.% Al and 1.2 wt.% C has wear resistance comparable to within 5% of the bainitic SAE 8620 steel forging currently used for the Bradley Fighting Vehicle track shoe and this cast Fe-Mn-Al-C steel, at equivalent tensile properties, would be 10% lighter.

  7. ADVANCED 3D LASER MICROSCOPY FOR MEASUREMENTS AND ANALYSIS OF VITRIFIED BONDED ABRASIVE TOOLS

    Directory of Open Access Journals (Sweden)

    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.

  8. Study on ultra-precision magnetic abrasive finishing process using low frequency alternating magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jinzhong, E-mail: wjz.0926@163.com; Zou, Yanhua, E-mail: yanhua@cc.utsunomiya-u.ac.jp; Sugiyama, Hitoshi, E-mail: sugiyama@cc.utsunomiya-u.ac.jp

    2015-07-15

    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.

  9. The unsteady nature of sea cliff retreat due to mechanical abrasion, failure and comminution feedbacks

    Science.gov (United States)

    Kline, Shaun W.; Adams, Peter N.; Limber, Patrick W.

    2014-08-01

    Sea cliff retreat is often linked to large waves, heavy precipitation and seismic events, but the specific operative mechanics have not been well constrained. In particular, what is the role of mechanical abrasion by beach sediments in cliff/platform evolution and how does it relate to the episodic nature of cliff retreat observed at certain locations? Here we present a simple, numerical model of sea cliff retreat that incorporates mechanical abrasion of a basal notch, threshold-controlled failure of the cantilevered block, and a feedback mechanism wherein retreat is dependent on the rate of sediment comminution within the surf zone. Using shore platform and cliff characteristics found in two coastal settings (the central California coast and the English North Sea coast), the model produces retreat rates comparable to those observed via field measurements. The highest retreat rates coincide with the steepest shore platforms and increasing wave height. Steeper platforms promote wave access to the cliff toe and, correspondingly, the receding cliff face produces additional accommodation space for the platform beach, preserving the erosive efficacy of the beach sediments. When exposed to energetic wave forcing, the slope of the inner platform segment controls retreat rates for concave platforms, whereas the slope of the outer platform segment exerts greater control for convex platforms. Platform beaches approached a long-term dynamic equilibrium on the concave profiles, leading to more consistent and steady retreat. Platform beaches were ephemeral on convex profiles, mirroring observed sand wave (Ord) migration on the Holderness coast, UK. These findings agree with previous field observations and support mechanical abrasion as a viable cause of temporal heterogeneity in cliff retreat rate for both coastlines.

  10. Abrasion and algal fouling of coarse material on the Murman littoral

    Directory of Open Access Journals (Sweden)

    Malavenda S. V.

    2017-03-01

    Full Text Available On the Murmansk coast of the Barents Sea the boulder littoral zone is widely spread mostly covered by Fucus communities. This is one of the most productive benthic communities of the Barents Sea. The studies of intertidal communities have the long history, but the dynamics of intertidal ecosystems due to surf and storms is not clear. The goal of the work is to identify the leading factors that determine the rate of abrasion of coarse material and fouling algae-macrophytes of the intertidal zone of Murman. The study has been conducted in the Zelenetskaya Bay of the Barents Sea on the basis of the biological station of the MMBI KSC RAS. The rate of abrasion has been carried out during 2004–2013, phyto-overgrowing – 2009–2013. In three pilot landfills 12 samples of coarse material have been exposed during the year (from July to next July. The weight change of the sample as well as species composition and biomass of algae of fouling communities have been investigated. The influence of the surf intensity, temperature of water and air has been analyzed (univariate analysis of variance ANOVA has been applied. It has been shown that on the littoral of the Murmansk coast the abrasion of coarse material is determined primarily by the number of storms, so the storm rate has been proposed. It has been revealed that the density of fouling boulders with macroalgae depends primarily on the intensity of the surf and the average gradient of air temperature. The basis for the emerging communities of annual species are green (Acrosiphonia arcta, Blidingia minima, Spongomorpha aeruginosa and brown algae (Pylaiella littoralis, Dictyosiphon chordaria. These algae groups are found everywhere in Fucus communities of the boulder intertidal zone of the Murman coast and probably they are the intermediate stage of fouling the coarse-grained material

  11. Effect of Erosion/Abrasion Challenge on the Dentin Tubule Occlusion Using Different Desensitizing Agents.

    Science.gov (United States)

    Canali, Gabriela D; Rached, Rodrigo N; Mazur, Rui F; Souza, Evelise M

    2017-01-01

    The aim of the study was to evaluate dentinal tubule occlusion, measuring the dentin permeability (Lp) and using different desensitizing agents before and after abrasive/erosive challenge. Dentin discs from 42 healthy human third molars were obtained. Minimum Lp was measured after a smear layer simulation using #600 SiC paper and maximum Lp after an immersion in 0.5 M EDTA. The specimens were treated with different desensitizers: two varnishes (Clinpro XT Varnish-CV, Fluor Protector-FP), a paste (Desensibilize Nano P-NP) and a gel (Oxa Gel-OG). The Lp of each specimen was measured immediately after the desensitizers' application. The discs were subjected to erosion/abrasion cycles for 7 days, with 0.5% citric acid solution (6x/day) and tooth brushing (3x/day). Lp was measured after the first, fourth and seventh day of the challenge. The data were analyzed by 3-way ANOVA with repeated measurements and by a Games-Howell test (α=5%). FP and CV did not show significant differences in Lp immediately after application until the 7th day (p<0.05). OG showed a significant increase in Lp after the 4th and 7th days. NP resulted in a significantly higher permeability compared to the other materials immediately after the application and after the 1st day of challenge. All the desensitizers reduced the dentin permeability immediately after application. However, only the varnishes were able to maintain the occlusive effect after the erosion/abrasion challenge.

  12. Hydrothermal treatment for TiN as abrasion resistant dental implant coating and its fibroblast response

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Standardization of a Volumetric Displacement Measurement for Two-Body Abrasion Scratch Test Data Analysis

    Science.gov (United States)

    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

  14. Influence of Utilization of High-Volumes of Class F Fly Ash on the Abrasion Resistance of Concrete

    Directory of Open Access Journals (Sweden)

    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.

  15. The effect of abrasive blasting on the strength of a joint between dental porcelain and metal base.

    Science.gov (United States)

    Pietnicki, Krzysztof; Wołowiec, Emilia; Klimek, Leszek

    2014-01-01

    This paper presents the effect of selected parameters of abrasive blasting on the strength of a joint between dental porcelain and metal base. Experiments were conducted for different grain sizes of abrasive material and different blasting angles, with a constant blasting pressure. InLine dental porcelain was fused on samples of cobalt-chromium alloy following abrasive blasting; they were subsequently subjected to shearing forces on a testing machine. The fractures were observed under an electron scanning microscope in order to determine the character and course of fracturing. Strength tests showed that the grain size of abrasive material was a parameter with the greatest effect on the strength. The best effects were achieved for samples subjected to abrasive blasting with material with grain size of 110 μm. No statistically significant differences were found for the strength of samples worked at different angles. The results of the fractographic examinations have shown that in all the samples, fracturing occurred mainly along the porcelain-metal boundary, with few cases of fracturing through porcelain.

  16. Development of a fixed abrasive slicing technique (FAST) for reducing the cost of photovoltaic wafers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Maintenance and Preservation of Concrete Structures. Report 3. Abrasion-Erosion Resistance of Concrete.

    Science.gov (United States)

    1980-07-01

    the length of service that may be expected from a specific concrete. It can be used to determine the relative resistance of a material to the abrasive... CONTRAT 5) ATA CMNTFC IIICU 385 I E.p....s e - F.u 5 IA# RIEIE5, ROOF? *Fpa*RSt ftaE A, --EtI PA.. ,.md II, CRD-C 9. ANA .REdF. IA.. ... 1.(2,. TIB...intended to provide a quantitative measurement of the length of service that may be expected from a specific concrete. Note: Other test methods for

  18. Study of abrasive wear rate of silicon using n-alcohols

    Science.gov (United States)

    Danyluk, S.

    1982-01-01

    The work carried out at the University of Illinois at Chicago for the Flat-Plate Solar Array Project under contract No. 956053 is summarized. The abrasion wear rate of silicon in a number of fluid environments and the parameters that influence the surface mechanical properties of silicon were determined. Three tests were carried out in this study: circular and linear multiple-scratch test, microhardness test and a three-point bend test. The pertinent parameters such as effect of surface orientation, dopant and fluid properties were sorted. A brief review and critique of previous work is presented.

  19. The impact of the bead width on the properties of the anti-abrasion surfacing weld

    Science.gov (United States)

    Beczkowski, Robert; Gucwa, Marek; Wróbel, Joanna; Kulawik, Adam

    2016-06-01

    This work presents the results of research on the anti-abrasion surfacing welds designated to operate under wear conditions. The main purpose of the work was to produce single-layer surface welds by means of semi-automatic hard-facing/surface welding with the use of filler material containing carbide precipitate and with the use of 10mm- and 20mm- wide beads. The samples were subject to visual and penetrant testing and to destructive testing in the form of macro and micro metallographic testing, hardness testing and bend testing with a view to determine the effect which the beads of various widths have on the analysed factors.

  20. Experimental verification of characteristics of magnetic abrasive polishing combined with ultrasonic vibration

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Dong Hyun; Kwak, Jae Seob [Dept. of Mechanical Engineering, Pukyung National University, Busan (Korea, Republic of)

    2015-09-15

    In this paper, we propose an ultrasonic magnetic abrasive polishing (US-MAP) technique to effectively machine a high-strength material, and we prove the efficiency of hybrid finishing. We use Taguchi's experimental method to determine the influence of each parameter. Based on the results, US-MAP exhibited a higher polishing efficiency than traditional MAP, and a suitable frequency for hybrid finishing was 28 kHz. When investigating the effect of the parameters on the surface roughness, the ultrasonic amplitude had the greatest effect. However, when machining with 55-μm amplitude, the machining efficiency decreased as the magnetic flux density varied.