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Sample records for tear surface parameters

  1. Tear Osmolarity and Correlation With Ocular Surface Parameters in Patients With Dry Eye.

    Science.gov (United States)

    Mathews, Priya M; Karakus, Sezen; Agrawal, Devika; Hindman, Holly B; Ramulu, Pradeep Y; Akpek, Esen K

    2017-11-01

    To analyze the distribution of tear film osmolarity in patients with dry eye and its association with other ocular surface parameters. Tear osmolarity and other quantitative dry eye parameters were obtained from patients with 1) clinically significant dry eye (significant symptoms and ocular surface staining, n = 131), 2) symptoms-only dry eye (significant symptoms but no significant ocular surface staining, n = 52), and 3) controls (no significant symptoms or staining, n = 42). Tear osmolarity varied significantly across groups (P = 0.01), with patients with clinically significant dry eye having the highest tear osmolarity (312.0 ± 16.9 mOsm/L), control patients having the lowest tear osmolarity (305.6 ± 9.7 mOsm/L), and patients with symptoms-only dry eye falling in between (307.4 ± 5.6 mOsm/L). Patients with clinically significant dry eye also tended to have a greater intereye difference in osmolarity (12.0 ± 13.4) than did the individuals with symptoms-only dry eye (9.1 ± 12.4) and controls (9.0 ± 7.4) (P = 0.06). In multivariable regression models, higher tear osmolarity was associated with higher Ocular Surface Disease Index, discomfort subscore (P = 0.02), and higher corneal and conjunctival staining scores (P eye tear osmolarity was not correlated with the corresponding tear film breakup time or Schirmer test (P > 0.05 for both). Individuals with symptomatic dry eye that is not yet clinically significant seem to have higher and more variable osmolarity measurements than controls, potentially indicating that changes in osmolarity precede clinical findings.

  2. Surface tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Takizuka, Tomonori; Kurita, Gen-ichi; Azumi, Masafumi; Takeda, Tatsuoki

    1985-10-01

    Surface tearing modes in tokamaks are studied numerically and analytically. The eigenvalue problem is solved to obtain the growth rate and the mode structure. We investigate in detail dependences of the growth rate of the m/n = 2/1 resistive MHD modes on the safety factor at the plasma surface, current profile, wall position, and resistivity. The surface tearing mode moves the plasma surface even when the wall is close to the surface. The stability diagram for these modes is presented. (author)

  3. Tear clearance implications for ocular surface health.

    Science.gov (United States)

    de Paiva, Cintia Sade; Pflugfelder, Stephen C

    2004-03-01

    Tear clearance/turnover provides a global assessment of the function of the lacrimal functional unit and of tear exchange on the ocular surface. It is an indirect measure of dry eye induced inflammation on the ocular surface. It shows better correlation with the severity of ocular irritation symptoms and corneal epithelial disease in dry eye than the Schirmer 1 test. Delayed tear clearance may prove to be the best measure for identifying patients with tear film disorders who may respond to anti-inflammatory therapy.

  4. Fracture Surface Morphology Under Ductile Tearing of Metal Plates

    DEFF Research Database (Denmark)

    Kacar, Muhammet F.; Tekoglu, Cihan; Nielsen, Kim Lau

    2017-01-01

    The present work takes as offset the hypothesis that microstructural parameters, related to particle size and distribution, govern the transition between crack surface morphologies observed in experiments. The key question is; why does tearing of a given metal plate leave a specific morphology...

  5. Tear-Film Evaporation Rate from Simultaneous Ocular-Surface Temperature and Tear-Breakup Area.

    Science.gov (United States)

    Dursch, Thomas J; Li, Wing; Taraz, Baseem; Lin, Meng C; Radke, Clayton J

    2018-01-01

    A corneal heat-transfer model is presented to quantify simultaneous measurements of fluorescein tear-breakup area (TBA) and ocular-surface temperature (OST). By accounting for disruption of the tear-film lipid layer (TFLL), we report evaporation rates through lipid-covered tear. The modified heat-transfer model provides new insights into evaporative dry eye. A quantitative analysis is presented to assess human aqueous tear evaporation rate (TER) through intact TFLLs from simultaneous in vivo measurement of time-dependent infrared OST and fluorescein TBA. We interpret simultaneous OST and TBA measurements using an extended heat-transfer model. We hypothesize that TBAs are ineffectively insulated by the TFLL and therefore exhibit higher TER than does that for a well-insulting TFLL-covered tear. As time proceeds, TBAs increase in number and size, thereby increasing the cornea area-averaged TER and decreasing OST. Tear-breakup areas were assessed from image analysis of fluorescein tear-film-breakup video recordings and are included in the heat-transfer description of OST. Model-predicted OSTs agree well with clinical experiments. Percent reductions in TER of lipid-covered tear range from 50 to 95% of that for pure water, in good agreement with literature. The physical picture of noninsulating or ruptured TFLL spots followed by enhanced evaporation from underlying cooler tear-film ruptures is consistent with the evaporative-driven mechanism for local tear rupture. A quantitative analysis is presented of in vivo TER from simultaneous clinical measurement of transient OST and TBA. The new heat-transfer model accounts for increased TER through expanding TBAs. Tear evaporation rate varies strongly across the cornea because lipid is effectively missing over tear-rupture troughs. The result is local faster evaporation compared with nonruptured, thick lipid-covered tear. Evaporative-driven tear-film ruptures deepen to a thickness where fluorescein quenching commences and local

  6. Trabecular microstructure and surface changes in the greater tuberosity in rotator cuff tears

    International Nuclear Information System (INIS)

    Jiang, Yebin; Zhao, Jenny; Ouyang, Xiaolong; Genant, Harry K.; Holsbeeck, Marnix T. van; Flynn, Michael J.

    2002-01-01

    Abstract Objective. When planning surgery in patients with rotator cuff tear, strength of bone at the tendon insertion and trabecular bone structure in the greater tuberosity are usually taken into consideration. We investigated radiographic changes in bone structure of the greater tuberosity in rotator cuff tears.Design. Twenty-two human cadaveric shoulders from subjects ranging from 55 to 75 years of age were obtained. The integrity of the rotator cuff was examined by sonography to determine if it is intact without any tear, or torn partially or completely. The humeral head was sectioned in 3 mm thick coronal slab sections and microradiographed. After digitization of the microradiographs and imaging processing with in-house semi-automated image processing software tools developed using software interfaces on a Sun workstation, the trabecular histomorphometrical structural parameters and connectivity in the greater tuberosity were quantified. The degenerative changes on the surface of the greater tuberosity were interpreted blindly by 2 independent readers.Results. Among the 22 shoulder specimens, the rotator cuff was found intact in 10 shoulders, partially in 7 and fully torn in 5. Statistically significant loss in apparent trabecular bone volume fraction, number of trabecular nodes, and number of trabecular branches, and a statistically significant increase in apparent trabecular separation and number of trabecular free ends were found in the greater tuberosity of the shoulders with tears. The loss was greater in association with full tear than in partial tear. Thickening of the cortical margin of the enthesis, irregularity of its surface, and calcification beyond the tidemark were observed in 2 (20%) shoulders with intact rotator cuff, in 6 (86%) shoulders with partial tear, and in 5 (100%) shoulders with full tear.Conclusions. Rotator cuff tears are associated with degenerative changes on the bone surface and with disuse osteopenia of the greater tuberosity

  7. Evaluating of Tear Meniscus Parameters with Optical Coherent Tomography in Dry-Eye Patients

    Directory of Open Access Journals (Sweden)

    Gülizar Soyugelen Demirok

    2013-08-01

    Full Text Available Purpose: To evaluate the changes in meniscus parameters with optical coherence tomography (OCT after treatment and consider the correlation between the OCT parameters and dry-eye tests. Material and Method: Thirty-two dry-eye patients and 30 healthy individuals were included. Visual acuities, biomicroscopic evaluation, Schirmer-I test, tear-break-up time (T-BUT, and lower-tear meniscus parameters measured with OCT were evaluated. Ocular surface disease index (OSDI was performed. The measurements were repeated on the 10th day and 1st month of the treatment. Lower tear meniscus height (LTMH, depth (LTMD, area (LTMA and α-angle were measured. The tear meniscus parameters of the dry-eye group were compared with the control group before treatment, and the correlation between the dry-eye tests and OCT measurements were evaluated. The change in the results of the dry-eye tests and OCT measurements with treatment were assessed. Results: There was statistically no significant difference between the age and gender of the patients in groups. Before treatment the mean Schirmer-I test, TBUT and OSDI scores were different. The LTMH and LTMA were higher in the control group. In the dry-eye group before treatment, there was a negative correlation between the OSDI score and OCT parameters, however, no meaningful correlation was observed between any other test and OCT parameters. Although there were no change in LTMD and α-angle with treatment, the 1st month values of LTMH and LTMA were significantly higher from the pre-treatment and 10th day values. Discussion: When diagnosing dry-eye, TBUT and OSDI scores were found to be more effective compared to Schirmer-I test for the diagnosis of dry eye. Although not adequate by itself, tear meniscus parameters measured with OCT, LTMH and LTMA, may be helpful for evaluating the efficacy of treatment, and the correlation of these two parameters with the OSDI score may increase the objectivity while questioning the

  8. The Impact of Visual Guided Order Picking on Ocular Comfort, Ocular Surface and Tear Function.

    Directory of Open Access Journals (Sweden)

    Angelika Klein-Theyer

    Full Text Available We investigated the effects of a visual picking system on ocular comfort, the ocular surface and tear function compared to those of a voice guided picking solution.Prospective, observational, cohort study.Institutional.A total of 25 young asymptomatic volunteers performed commissioning over 10 hours on two consecutive days.The operators were guided in the picking process by two different picking solutions, either visually or by voice while their subjective symptoms and ocular surface and tear function parameters were recorded.The visual analogue scale (VAS values, according to subjective dry eye symptoms, in the visual condition were significantly higher at the end of the commissioning than the baseline measurements. In the voice condition, the VAS values remained stable during the commissioning. The tear break-up time (BUT values declined significantly in the visual condition (pre-task: 16.6 sec and post-task: 9.6 sec in the right eyes, that were exposed to the displays, the left eyes in the visual condition showed only a minor decline, whereas the BUT values in the voice condition remained constant (right eyes or even increased (left eyes over the time. No significant differences in the tear meniscus height values before and after the commissioning were observed in either condition.In our study, the use of visually guided picking solutions was correlated with post-task subjective symptoms and tear film instability.

  9. Tear film and ocular surface assessment in psoriasis.

    Science.gov (United States)

    Aragona, Emanuela; Rania, Laura; Postorino, Elisa Imelde; Interdonato, Alberto; Giuffrida, Roberta; Cannavò, Serafinella Patrizia; Puzzolo, Domenico; Aragona, Pasquale

    2018-03-01

    Psoriasis is a skin disease with also systemic involvement: its impact on the eye is not well established and often clinically underestimated. Aim of this study was to investigate the presence of ocular discomfort symptoms and of ocular surface changes in a population of patients with psoriasis. For this cross-sectional, comparative study, 66 patients with psoriasis were subdivided according to the presence of arthritis and to the use of biological therapy. All patients underwent clinical evaluation with the following tests: Ocular Surface Disease Index Questionnaire, Tearscope examination, meibometry, tear film breakup time, corneal and conjunctival fluorescein staining, Schirmer I test, corneal aesthesiometry, meibomian gland dysfunction (MGD) assessment and conjunctival impression cytology. 28 healthy subjects were also enrolled and treated with the same clinical tests. A statistical analysis of the results was performed. Patients with psoriasis showed a significant deterioration of the ocular surface tests, if compared with healthy subjects, demonstrated by tear film lipid layer alteration, tear film instability, corneal and conjunctival epithelial suffering and mild squamous metaplasia at impression cytology. No differences were found in ocular surface test results of the psoriatic group when patients were divided according to the presence of arthritis, whereas the anti-inflammatory treatment with biological drugs demonstrated a significant improvement of corneal stain and MGD. Our findings suggest that the ocular surface involvement in patients with psoriasis indicates the need of periodic ophthalmological examinations to diagnose the condition and allow a proper treatment, so contributing to the amelioration of patients' quality of life. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  10. Tear function and ocular surface after Muller muscle-conjunctival resection.

    Science.gov (United States)

    Uğurbaş, Suat Hayri; Alpay, Atilla; Bahadır, Burak; Uğurbaş, Sılay Cantürk

    2014-05-01

    Muller muscle-conjunctival resection (MCR) is a surgical technique to correct mild and moderate ptosis. In this study, tear function tests and ocular surface are evaluated in patients who underwent unilateral surgery. Sixteen patients with normal preoperative tear function who underwent unilateral MCR were evaluated prospectively. The fellow eyes of the patients were taken as the control group. A dry eye assessment questionnaire, Schirmer testing, tear film break-up time, fluorescein stain, Rose-Bengal stain, and conjunctival impression cytology were used to assess the tear film functions and ocular surface changes in the operated and non-operated eyes. There was no statistically significant difference in the tear function tests and goblet cell densities between the operated and non-operated eyes. The results indicate that an MCR procedure has no apparent effect on tear function tests and goblet cell density in patients with normal preoperative tear function.

  11. Effect of altered eating habits and periods during Ramadan fasting on intraocular pressure, tear secretion, corneal and anterior chamber parameters

    NARCIS (Netherlands)

    Kerimoglu, H.; Ozturk, B.; Gunduz, K.; Bozkurt, B.; Kamis, U.; Okka, M.

    Purpose To determine whether altered eating habits and periods, especially the pre-dawn meal, during Ramadan fasting have any significant effect on intraocular pressure (IOP), tear secretion, corneal and anterior chamber parameters. Methods IOP, basal tear secretion (BTS), reflex tear secretion

  12. Assessment of tear osmolarity and other dry eye parameters in post-LASIK eyes.

    Science.gov (United States)

    Hassan, Ziad; Szalai, Eszter; Berta, Andras; Modis, Laszlo; Nemeth, Gabor

    2013-07-01

    To assess the tear osmolarity using the TearLab device after laser in situ keratomileusis (LASIK) and to compare the values with those obtained by traditional tear film tests before and after the procedure. Thirty eyes of 15 refractive surgery candidates (5 men and 10 women of mean age: 30.55 ± 11.79 years) were examined. Using a special questionnaire (Ocular Surface Disease Index), subjective dry eye complaints were evaluated, and then, the tear osmolarity was measured with the TearLab system (TearLab Corporation) and conventional dry eye tests were carried out. Examinations were performed preoperatively and at 1, 30, and 60 days after the surgery. The mean value of tear osmolarity was 303.62 ± 12.29 mOsm/L before the surgery and 303.58 ± 20.14 mOsm/L at 60 days after the treatment (P = 0.69). Mean lid parallel conjunctival folds value was 0.68 ± 0.68 before the procedure and 0.58 ± 0.65 subsequent to surgery (P = 0.25). Meibomian gland dysfunction was not detected. No significant deviation was observed in the values of Schirmer test, corneal staining, tear break-up time, and lid parallel conjunctival folds when compared with postoperatively obtained values during the follow-up period (P > 0.05). During LASIK flap creation, intact corneal innervation is damaged, and the ocular surface lacrimal functional unit can be impaired. In our study, no abnormal dry eye test results were observed before or after the procedure. Based on our results, LASIK treatment is safe for dry eye involving the administration of adequate artificial tears for a minimum of 3 months.

  13. Comparative study on fractal analysis of interferometry images with application to tear film surface quality assessment.

    Science.gov (United States)

    Szyperski, Piotr D

    2018-06-01

    The purpose of this research was to evaluate the applicability of the fractal dimension (FD) estimators to assess lateral shearing interferometric (LSI) measurements of tear film surface quality. Retrospective recordings of tear film measured with LSI were used: 69 from healthy subjects and 41 from patients diagnosed with dry eye syndrome. Five surface quality descriptors were considered, four based on FD and a previously reported descriptor operating in a spatial frequency domain (M 2 ), presenting temporal kinetics of post-blink tear film. A set of 12 regression parameters has been extracted and analyzed for classification purposes. The classifiers are assessed in terms of receiver operating characteristics and areas under their curves (AUC). Also, the computational loads are estimated. The maximum AUC of 82.4% was achieved for M 2 , closely followed by the binary box-counting (BBC) FD estimator with AUC=78.6%. For all descriptors, statistically significant differences between the subject groups were found (pfilm kinetics. They provide a viable alternative to previously used spectral counter parameters, and at the same time allow higher computational efficiency.

  14. Goldmann tonometry tear film error and partial correction with a shaped applanation surface.

    Science.gov (United States)

    McCafferty, Sean J; Enikov, Eniko T; Schwiegerling, Jim; Ashley, Sean M

    2018-01-01

    The aim of the study was to quantify the isolated tear film adhesion error in a Goldmann applanation tonometer (GAT) prism and in a correcting applanation tonometry surface (CATS) prism. The separation force of a tonometer prism adhered by a tear film to a simulated cornea was measured to quantify an isolated tear film adhesion force. Acrylic hemispheres (7.8 mm radius) used as corneas were lathed over the apical 3.06 mm diameter to simulate full applanation contact with the prism surface for both GAT and CATS prisms. Tear film separation measurements were completed with both an artificial tear and fluorescein solutions as a fluid bridge. The applanation mire thicknesses were measured and correlated with the tear film separation measurements. Human cadaver eyes were used to validate simulated cornea tear film separation measurement differences between the GAT and CATS prisms. The CATS prism tear film adhesion error (2.74±0.21 mmHg) was significantly less than the GAT prism (4.57±0.18 mmHg, p film adhesion error was independent of applanation mire thickness ( R 2 =0.09, p =0.04). Fluorescein produces more tear film error than artificial tears (+0.51±0.04 mmHg; p film adhesion error (1.40±0.51 mmHg) was significantly less than that of the GAT prism (3.30±0.38 mmHg; p =0.002). Measured GAT tear film adhesion error is more than previously predicted. A CATS prism significantly reduced tear film adhesion error bŷ41%. Fluorescein solution increases the tear film adhesion compared to artificial tears, while mire thickness has a negligible effect.

  15. Interferometer for measuring the dynamic surface topography of a human tear film

    Science.gov (United States)

    Primeau, Brian C.; Greivenkamp, John E.

    2012-03-01

    The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. Following a blink, the tear film quickly smoothes and starts to become irregular after 10 seconds. This irregularity can affect comfort and vision quality. An in vivo method of characterizing dynamic tear films has been designed based upon a near-infrared phase-shifting interferometer. This interferometer continuously measures light reflected from the tear film, allowing sub-micron analysis of the dynamic surface topography. Movies showing the tear film behavior can be generated along with quantitative metrics describing changes in the tear film surface. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or corneal topography and provides better sensitivity and resolution than shearing interferometry methods. The interferometer design is capable of identifying features in the tear film much less than a micron in height with a spatial resolution of about ten microns over a 6 mm diameter. This paper presents the design of the tear film interferometer along with the considerations that must be taken when designing an interferometer for on-eye diagnostics. Discussions include eye movement, design of null optics for a range of ocular geometries, and laser emission limits for on-eye interferometry.

  16. Mechanical tearing of graphene on an oxidizing metal surface

    International Nuclear Information System (INIS)

    George, Lijin; Gupta, Aparna; Shaina, P R; Jaiswal, Manu; Gupta, Nandita Das

    2015-01-01

    Graphene, the thinnest possible anticorrosion and gas-permeation barrier, is poised to transform the protective coatings industry for a variety of surface applications. In this work, we have studied the structural changes of graphene when the underlying copper surface undergoes oxidation upon heating. Single-layer graphene directly grown on a copper surface by chemical vapour deposition was annealed under ambient atmosphere conditions up to 400 °C. The onset temperature of the surface oxidation of copper is found to be higher for graphene-coated foils. Parallel arrays of graphene nanoripples are a ubiquitous feature of pristine graphene on copper, and we demonstrate that these form crucial sites for the onset of the oxidation of copper, particularly for ∼0.3–0.4 μm ripple widths. In these regions, the oxidation proceeds along the length of the nanoripples, resulting in the formation of parallel stripes of oxidized copper regions. We demonstrate from temperature-dependent Raman spectroscopy that the primary defect formation process in graphene involves boundary-type defects rather than vacancy or sp"3-type defects. This observation is consistent with a mechanical tearing process that splits graphene into small polycrystalline domains. The size of these is estimated to be sub-50 nm. (paper)

  17. Mechanical tearing of graphene on an oxidizing metal surface.

    Science.gov (United States)

    George, Lijin; Gupta, Aparna; Shaina, P R; Das Gupta, Nandita; Jaiswal, Manu

    2015-12-11

    Graphene, the thinnest possible anticorrosion and gas-permeation barrier, is poised to transform the protective coatings industry for a variety of surface applications. In this work, we have studied the structural changes of graphene when the underlying copper surface undergoes oxidation upon heating. Single-layer graphene directly grown on a copper surface by chemical vapour deposition was annealed under ambient atmosphere conditions up to 400 °C. The onset temperature of the surface oxidation of copper is found to be higher for graphene-coated foils. Parallel arrays of graphene nanoripples are a ubiquitous feature of pristine graphene on copper, and we demonstrate that these form crucial sites for the onset of the oxidation of copper, particularly for ∼0.3-0.4 μm ripple widths. In these regions, the oxidation proceeds along the length of the nanoripples, resulting in the formation of parallel stripes of oxidized copper regions. We demonstrate from temperature-dependent Raman spectroscopy that the primary defect formation process in graphene involves boundary-type defects rather than vacancy or sp(3)-type defects. This observation is consistent with a mechanical tearing process that splits graphene into small polycrystalline domains. The size of these is estimated to be sub-50 nm.

  18. Expression of Lipid Peroxidation Markers in the Tear Film and Ocular Surface of Patients with Non-Sjogren Syndrome: Potential Biomarkers for Dry Eye Disease.

    Science.gov (United States)

    Choi, Won; Lian, Cui; Ying, Li; Kim, Ga Eon; You, In Cheon; Park, Soo Hyun; Yoon, Kyung Chul

    2016-09-01

    To investigate the expression of lipid peroxidation markers in the tear film and ocular surface and their correlation with disease severity in patients with dry eye disease. The concentrations of hexanoyl-lysine (HEL), 4-hydroxy-2-nonenal (HNE), and malondialdehyde (MDA) were measured with enzyme-linked immunosorbent assays in tears obtained from 44 patients with non-Sjogren syndrome dry eye and 33 control subjects. The correlations between the marker levels and the tear film and ocular surface parameters, including tear film break-up time (BUT), Schirmer tear value, tear clearance rate, keratoepitheliopathy scores, corneal sensitivity, conjunctival goblet cell density, and symptom score, were analyzed. The expression of the lipid peroxidation markers HEL, 4-HNE, and MDA in the conjunctiva was evaluated using immunohistochemistry. The concentrations of HEL, 4-HNE, and MDA were 279.84 ± 69.98 nmol/L, 0.02 ± 0.01 μg/mL, and 3.80 ± 1.05 pmol/mg in control subjects and 283.21 ± 89.67 nmol/L (p = 0.97), 0.20 ± 0.03 μg/mL (p dry eye patients. 4-HNE and MDA levels significantly correlated with BUT, Schirmer tear value, tear clearance rate, keratoepitheliopathy scores, conjunctival goblet cell density, and symptom score (p dry eye patients. The expression of late lipid peroxidation markers, 4-HNE and MDA, increases in the tear film and ocular surface of patients with dry eye. The levels correlate with various tear film and ocular surface parameters and may reflect the severity of dry eye disease.

  19. Goldmann tonometry tear film error and partial correction with a shaped applanation surface

    Directory of Open Access Journals (Sweden)

    McCafferty SJ

    2018-01-01

    Full Text Available Sean J McCafferty,1–4 Eniko T Enikov,5 Jim Schwiegerling,2,3 Sean M Ashley1,3 1Intuor Technologies, 2Department of Ophthalmology, University of Arizona College of Medicine, 3University of Arizona College of Optical Science, 4Arizona Eye Consultants, 5Department of Mechanical and Aerospace, University of Arizona College of Engineering, Tucson, AZ, USA Purpose: The aim of the study was to quantify the isolated tear film adhesion error in a Goldmann applanation tonometer (GAT prism and in a correcting applanation tonometry surface (CATS prism.Methods: The separation force of a tonometer prism adhered by a tear film to a simulated cornea was measured to quantify an isolated tear film adhesion force. Acrylic hemispheres (7.8 mm radius used as corneas were lathed over the apical 3.06 mm diameter to simulate full applanation contact with the prism surface for both GAT and CATS prisms. Tear film separation measurements were completed with both an artificial tear and fluorescein solutions as a fluid bridge. The applanation mire thicknesses were measured and correlated with the tear film separation measurements. Human cadaver eyes were used to validate simulated cornea tear film separation measurement differences between the GAT and CATS prisms.Results: The CATS prism tear film adhesion error (2.74±0.21 mmHg was significantly less than the GAT prism (4.57±0.18 mmHg, p<0.001. Tear film adhesion error was independent of applanation mire thickness (R2=0.09, p=0.04. Fluorescein produces more tear film error than artificial tears (+0.51±0.04 mmHg; p<0.001. Cadaver eye validation indicated the CATS prism’s tear film adhesion error (1.40±0.51 mmHg was significantly less than that of the GAT prism (3.30±0.38 mmHg; p=0.002.Conclusion: Measured GAT tear film adhesion error is more than previously predicted. A CATS prism significantly reduced tear film adhesion error by ~41%. Fluorescein solution increases the tear film adhesion compared to

  20. Sea surface stability parameters

    International Nuclear Information System (INIS)

    Weber, A.H.; Suich, J.E.

    1978-01-01

    A number of studies dealing with climatology of the Northwest Atlantic Ocean have been published in the last ten years. These published studies have dealt with directly measured meteorological parameters, e.g., wind speed, temperature, etc. This information has been useful because of the increased focus on the near coastal zone where man's activities are increasing in magnitude and scope, e.g., offshore power plants, petroleum production, and the subsequent environmental impacts of these activities. Atmospheric transport of passive or nonpassive material is significantly influenced by the turbulence structure of the atmosphere in the region of the atmosphere-ocean interface. This research entails identification of the suitability of standard atmospheric stability parameters which can be used to determine turbulence structure; the calculation of these parameters for the near-shore and continental shelf regions of the U.S. east coast from Cape Hatteras to Miami, Florida; and the preparation of a climatology of these parameters. In addition, a climatology for average surface stress for the same geographical region is being prepared

  1. The ocular surface and tear film and their dysfunction in dry eye disease.

    Science.gov (United States)

    Rolando, M; Zierhut, M

    2001-03-01

    The ocular surface, tear film, lacrimal glands, and eyelids act as a functional unit to preserve the quality of the refractive surface of the eye and to resist injury and protect the eye against changing bodily and environmental conditions. Events that disturb the homeostasis of this functional unit can result in a vicious cycle of ocular surface disease. The tear film is the most dynamic structure of the functional unit, and its production and turnover is essential to maintaining the health of the ocular surface. Classically, the tear film is reported to be composed of three layers: the mucin, aqueous, and lipid layers. The boundaries and real thickness of such layers is still under discussion. A dysfunction of any of these layers can result in dry eye disease.

  2. Management of the ocular surface and tear film before, during, and after laser in situ keratomileusis.

    Science.gov (United States)

    Albietz, Julie M; Lenton, Lee M

    2004-01-01

    To identify evidence-based, best practice strategies for managing the ocular surface and tear film before, during, and after laser in situ keratomileusis (LASIK). After a comprehensive review of relevant published literature, evidence-based recommendations for best practice management strategies are presented. Symptoms of ocular irritation and signs of dysfunction of the integrated lacrimal gland/ocular surface functional gland unit are common before and after LASIK. The status of the ocular surface and tear film before LASIK can impact surgical outcomes in terms of potential complications during and after surgery, refractive outcome, optical quality, patient satisfaction, and the severity and duration of dry eye after LASIK. Before LASIK, the health of the ocular surface should be optimized and patients selected appropriately. Dry eye before surgery and female gender are risk factors for developing chronic dry eye after LASIK. Management of the ocular surface during LASIK can minimize ocular surface damage and the risk of adverse outcomes. Long-term management of the tear film and ocular surface after LASIK can reduce the severity and duration of dry eye symptoms and signs. Strategies to manage the integrated ocular surface/lacrimal gland functional unit before, during, and after LASIK can optimize outcomes. As problems with the ocular surface and tear film are relatively common, attention should focus on the use and improvement of evidence-based management strategies.

  3. Non-linear self-reinforced growth of tearing modes with multiple rational surfaces

    International Nuclear Information System (INIS)

    Maschke, E.K.; Persson, M.; Dewar, R.L.; Australian National Univ., Canberra, ACT

    1993-06-01

    The non-linear evolution of tearing modes with multiple rational surfaces is discussed. It is demonstrated that, in the presence of small differential rotation, the non-linear growth might be faster than exponential. This growth occurs as the rotation frequencies of the plasma at the different rational surfaces go into equilibrium

  4. Isolation of the ocular surface to treat dysfunctional tear syndrome associated with computer use.

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    Yee, Richard W; Sperling, Harry G; Kattek, Ashballa; Paukert, Martin T; Dawson, Kevin; Garcia, Marcie; Hilsenbeck, Susan

    2007-10-01

    Dysfunctional tear syndrome (DTS) associated with computer use is characterized by mild irritation, itching, redness, and intermittent tearing after extended staring. It frequently involves foreign body or sandy sensation, blurring of vision, and fatigue, worsening especially at the end of the day. We undertook a study to determine the effectiveness of periocular isolation using microenvironment glasses (MEGS) alone and in combination with artificial tears in alleviating the symptoms and signs of dry eye related to computer use. At the same time, we evaluated the relative ability of a battery of clinical tests for dry eye to distinguish dry eyes from normal eyes in heavy computer users. Forty adult subjects who used computers 3 hours or more per day were divided into dry eye sufferers and controls based on their scores on the Ocular Surface Disease Index (OSDI). Baseline scores were recorded and ocular surface assessments were made. On four subsequent visits, the subjects played a computer game for 30 minutes in a controlled environment, during which one of four treatment conditions were applied, in random order, to each subject: 1) no treatment, 2) artificial tears, 3) MEGS, and 4) artificial tears combined with MEGS. Immediately after each session, subjects were tested on: a subjective comfort questionnaire, tear breakup time (TBUT), fluorescein staining, lissamine green staining, and conjunctival injection. In this study, a significant correlation was found between cumulative lifetime computer use and ocular surface disorder, as measured by the standardized OSDI index. The experimental and control subjects were significantly different (P0.05. Isolation of the ocular surface alone produced significant improvements in comfort scores and TBUT and a consistent trend of improvement in fluorescein staining and lissamine green staining. Isolation plus tears produced a significant improvement in lissamine green staining. The subjective comfort inventory and the TBUT

  5. Surface Properties of Squalene/Meibum Films and NMR Confirmation of Squalene in Tears

    Directory of Open Access Journals (Sweden)

    Slavyana Ivanova

    2015-09-01

    Full Text Available Squalene (SQ possesses a wide range of pharmacological activities (antioxidant, drug carrier, detoxifier, hydrating, emollient that can be of benefit to the ocular surface. It can come in contact with human meibum (hMGS; the most abundant component of the tear film lipid layer as an endogenous tear lipid or from exogenous sources as eyelid sebum or pharmaceuticals. The aims of this study were to determine (i if SQ is in tear lipids and (ii its influence on the surface properties of hMGS films. Heteronuclear single quantum correlation NMR confirmed 7 mol % SQ in Schirmer’s strips extracts. The properties of SQ/hMGS pseudo-binary films at the air/water interface were studied with Langmuir surface balance, stress-relaxation dilatational rheology and Brewster angle microscopy. SQ does not possess surfactant properties. When mixed with hMGS squalene (i localized over the layers’ thinner regions and (ii did not affect the film pressure at high compression. Therefore, tear SQ is unlikely to instigate dry eye, and SQ can be used as a safe and “inert” ingredient in formulations to protect against dry eye. The layering of SQ over the thinner film regions in addition to its pharmacological properties could contribute to the protection of the ocular surface.

  6. Surface excitation parameter for rough surfaces

    International Nuclear Information System (INIS)

    Da, Bo; Salma, Khanam; Ji, Hui; Mao, Shifeng; Zhang, Guanghui; Wang, Xiaoping; Ding, Zejun

    2015-01-01

    Graphical abstract: - Highlights: • Instead of providing a general mathematical model of roughness, we directly use a finite element triangle mesh method to build a fully 3D rough surface from the practical sample. • The surface plasmon excitation can be introduced to the realistic sample surface by dielectric response theory and finite element method. • We found that SEP calculated based on ideal plane surface model are still reliable for real sample surface with common roughness. - Abstract: In order to assess quantitatively the importance of surface excitation effect in surface electron spectroscopy measurement, surface excitation parameter (SEP) has been introduced to describe the surface excitation probability as an average number of surface excitations that electrons can undergo when they move through solid surface either in incoming or outgoing directions. Meanwhile, surface roughness is an inevitable issue in experiments particularly when the sample surface is cleaned with ion beam bombardment. Surface roughness alters not only the electron elastic peak intensity but also the surface excitation intensity. However, almost all of the popular theoretical models for determining SEP are based on ideal plane surface approximation. In order to figure out whether this approximation is efficient or not for SEP calculation and the scope of this assumption, we proposed a new way to determine the SEP for a rough surface by a Monte Carlo simulation of electron scattering process near to a realistic rough surface, which is modeled by a finite element analysis method according to AFM image. The elastic peak intensity is calculated for different electron incident and emission angles. Assuming surface excitations obey the Poisson distribution the SEPs corrected for surface roughness are then obtained by analyzing the elastic peak intensity for several materials and for different incident and emission angles. It is found that the surface roughness only plays an

  7. The effect of smoking on the ocular surface and the precorneal tear film

    Directory of Open Access Journals (Sweden)

    Jyothi Thomas

    2012-04-01

    Full Text Available BackgroundSmoking, both active and passive, creates a plethora ofhealth‐related problems, which primarily affect thecardiovascular and respiratory systems. There is very littleevidence on the effects of tobacco smoke on the eye,especially regarding anterior ocular surface relatedpathology. This study was undertaken to determine theeffects of smoking on the ocular surface and the tear film insmokers.MethodsA total of 51 (102 eyes smokers and 50 (100 eyes age‐ andgender‐matched healthy non‐smokers were included in thisstudy. The ocular surface was evaluated by measuring tearfilm break‐up time, surface staining with fluorescein, andcorneal and conjunctival sensitivities, and by completing theSchirmer’s II test. Data was analysed using StatisticalPackage for Social Sciences (SPSS version 11.5. A p valueless than 0.05 was considered statistically significant.ResultsThe smoker group had significantly lower tear film break‐uptime, and corneal and conjunctival sensitivity than the nonsmokergroup. Punctate staining was significantly higher inthe smoker group than the non‐smoker group. There wasno statistically significant difference in Schirmer’s II testresults between the smoker and non‐smoker group.ConclusionSmoking caused adverse effects on the precorneal tear filmand there was strong association between smoking and tearfilm instability. Although a causative relationship could notbe determined, there is a need for further longitudinalstudies.

  8. Effect of altered eating habits and periods during Ramadan fasting on intraocular pressure, tear secretion, corneal and anterior chamber parameters.

    Science.gov (United States)

    Kerimoglu, H; Ozturk, B; Gunduz, K; Bozkurt, B; Kamis, U; Okka, M

    2010-01-01

    To determine whether altered eating habits and periods, especially the pre-dawn meal, during Ramadan fasting have any significant effect on intraocular pressure (IOP), tear secretion, corneal and anterior chamber parameters. IOP, basal tear secretion (BTS), reflex tear secretion (RTS), and Pentacam measurements of 31 healthy volunteers were performed at 0800 and 1600 hours during Ramadan fasting and 1 month later during non-fasting period. Comparison of measurements between fasting and non-fasting periods at 0800 hours revealed significantly higher values for IOP (P=0.005), RTS (P=0.006), and BTS (P=0.014) during fasting. Conversely at 1600 hours, IOP was significantly lower during fasting (P=0.013) and no statistically significant difference was noted for RTS and BTS. IOP showed a diurnal variation of 2.45 mmHg (P<0.001) and BTS showed a 3.06 mm decrease (P=0.04) during the fasting period. No significant differences could be found in the corneal and anterior chamber parameters during fasting and non-fasting periods. Our results revealed that fluid loading at the pre-dawn meal during Ramadan fasting might increase the IOP and tear secretion in the early morning period and these values decrease remarkably at the end of 12 h of fasting due to dehydration.

  9. Tear Film and Ocular Surface Changes in Patients Receiving Systemic Isotretinoin

    Directory of Open Access Journals (Sweden)

    Ebru Nevin Çetin

    2013-10-01

    Full Text Available Purpose: Our aim in this study was to assess the ocular surface and tear film changes in acne vulgaris patients receiving systemic isotretinoin. Material and Method: Twenty-two eyes of 22 patients who received oral isotretinoin (roaccutane®, 0.7 mg/kg/day for nodular acne vulgaris were enrolled in this prospective study. Tear film break-up time (BUT, Schirmer 1 test scores with anesthesia, ocular surface disease index (OSDI scores and conjunctival impression cytology scores were recorded before treatment and at 3- and 6-month visits following the beginning of treatment. Results: BUT values decreased and OSDI scores significantly increased at 3 months after treatment (p=0.007 and p=0.018, paired samples test. Schirmer scores did not significantly change by isotretinoin treatment. Of 9 eyes with impression cytology specimens, 4 revealed normal conjunctival findings before treatment. At the 3rd month, there was an increase in the scores characterized by decrease of Goblet cells, and at 6 months of treatment, normal conjunctival findings did not exist in any of the patients (p=0.004, Friedman test. Discussion: Systemic isotretinoin treatment can cause alterations in the tear film and cause dry eye symptoms. (Turk J Ophthalmol 2013; 43: 309-12

  10. Evaluation of Visual Field Test Parameters after Artificial Tear Administration in Patients with Glaucoma and Dry Eye.

    Science.gov (United States)

    Özyol, Pelin; Özyol, Erhan; Karalezli, Aylin

    2018-01-01

    To examine the effect of a single dose of artificial tear administration on automated visual field (VF) testing in patients with glaucoma and dry eye syndrome. A total of 35 patients with primary open-angle glaucoma experienced in VF testing with symptoms of dry eye were enrolled in this study. At the first visit, standard VF testing was performed. At the second and third visits with an interval of one week, while the left eyes served as control, one drop of artificial tear was administered to each patient's right eye, and then VF testing was performed again. The reliability parameters, VF indices, number of depressed points at probability levels of pattern deviation plots, and test times were compared between visits. No significant difference was observed in any VF testing parameters of control eyes (P>0.05). In artificial tear administered eyes, significant improvement was observed in test duration, mean deviation, and the number of depressed points at probability levels (P˂0.5%, P˂1%, P˂2) of pattern deviation plots (P˂0.05). The post-hoc test revealed that artificial tear administration elicited an improvement in test duration, mean deviation, and the number of depressed points at probability levels (P˂0.5%, P˂1%, P˂2%) of pattern deviation plots from first visit to second and third visits (P˂0.01, for all comparisons). The intraclass correlation coefficient for the three VF test indices was found to be between 0.735 and 0.85 (P<0.001, for all). A single dose of artificial tear administration immediately before VF testing seems to improve test results and decrease test time.

  11. Corneal sensitivity, ocular surface health and tear film stability after punctal plug therapy of aqueous deficient dry eye

    Directory of Open Access Journals (Sweden)

    Azza Mohamed Ahmed Said

    2016-11-01

    Full Text Available AIM: To evaluate the effect of punctal occlusion using thermosensitive (smart plug versus silicone plug for management of aqueous deficient dry eye on corneal sensitivity, ocular surface health and tear film stability. METHODS: A comparative prospective interventional case study included 45 patients with bilateral severe form of aqueous deficient dry eye. In each patient, the smart plug was inserted in the lower punctum of the right eye which was considered as study group 1 and silicone plug was inserted in the lower punctum of the left eye of the same patient which was considered as study group 2. All patients were subjected to careful history taking and questionnaire for subjective assessment of severity of symptoms. Corneal sensitivity, corneal fluorescein, rose bengal staining, Schirmer’s I test, tear film break up time and conjunctival impression cytology were performed pre and 1, 3 and 6mo post plug insertion. RESULTS: A statistically significant improvement in subjective and objective manifestations occurred following treatment with both types of plugs (P<0.01. The thermosensitive plug caused significant overall improvement, decrease in frequency of application of tear substitutes and improvement of conjunctival impression cytology parameters in the inserted side (P<0.01. Canaliculitis was reported in two eyes (4.4% following punctal occlusion using thermosensitive plug (study group 1. Spontaneous plug loss occurred in 21 eyes (46.6% in the silicone plug group (study group 2. CONCLUSION: Improvement of subjective and objective manifestations of aqueous deficient dry eye occurs following punctal plug occlusion. Thermosensitive plug has good patient's compliance with fewer complications and lower rates of loss compared to the silicone plug.

  12. Transtendon, Double-Row, Transosseous-Equivalent Arthroscopic Repair of Partial-Thickness, Articular-Surface Rotator Cuff Tears

    OpenAIRE

    Dilisio, Matthew F.; Miller, Lindsay R.; Higgins, Laurence D.

    2014-01-01

    Arthroscopic transtendinous techniques for the arthroscopic repair of partial-thickness, articular-surface rotator cuff tears offer the advantage of minimizing the disruption of the patient's remaining rotator cuff tendon fibers. In addition, double-row fixation of full-thickness rotator cuff tears has shown biomechanical advantages. We present a novel method combining these 2 techniques for transtendon, double-row, transosseous-equivalent arthroscopic repair of partial-thickness, articular-s...

  13. Surface Chemistry Interactions of Cationorm with Films by Human Meibum and Tear Film Compounds

    Directory of Open Access Journals (Sweden)

    Georgi As. Georgiev

    2017-07-01

    Full Text Available Cationorm® (CN cationic nanoemulsion was demonstrated to enhance tear film (TF stability in vivo possibly via effects on tear film lipid layer (TFLL. Therefore the interactions of CN with human meibum (MGS and TFLL in vitro and in vivo deserve special study. MGS and CN were spread at the air/water interface of a Langmuir surface balance to ensure a range of MGS/CN oil phase ratios: 20/1, 10/1, 5/1, 3/1, 2/1 and 1/1. The films capability to reorganize during dynamic area changes was evaluated via the surface pressure-area compression isotherms and step/relaxation dilatational rheology studies. Films structure was monitored with Brewster angle microscopy. CN/TFLL interactions at the ocular surface were monitored with non-contact specular microscopy. The in vitro studies of MGS/CN layers showed that (i CN inclusion (at fixed MGS content increased film elasticity and thickness and that (ii CN can compensate for moderate meibum deficiency in MGS/CN films. In vivo CN mixed with TFLL in a manner similar to CN/MGS interactions in vitro, and resulted in enhanced thickness of TFLL. In vitro and in vivo data complement each other and facilitated the study of the composition-structure-function relationship that determines the impact of cationic nanoemulsions on TF.

  14. Improved accuracy in the estimation of the tearing mode stability parameters (Δ′ and wc) using 2D ECEI data in KSTAR

    International Nuclear Information System (INIS)

    Choi, Minjun J; Yun, Gunsu S; Lee, Woochang; Park, Hyeon K; Park, Young-Seok; Sabbagh, Steve A; Gibson, Kieran J; Bowman, Christopher; Domier, Calvin W; Luhmann, Neville C Jr; Bak, Jun-Gyo; Lee, Sang G

    2014-01-01

    The accuracy in estimation of two important tearing mode stability parameters (Δ′ and w c ) is improved by employing two-dimensional (2D) ECE imaging data which help one to overcome the resolution limit of conventional one-dimensional data. The experimentally measured 2D images are directly compared with synthetic ones from a tearing mode T e model to estimate the parameters and an excellent agreement is achieved. The results imply that the observed tearing mode is classically stable but has non-negligible bootstrap current drive. (paper)

  15. Ocular Surface and Tear Film Changes in Older Women Working with Computers

    Directory of Open Access Journals (Sweden)

    Alfredo Ribelles

    2015-01-01

    Full Text Available The aim of this work is to investigate changes in the ocular surface (OS and tear film (TF by means of questionnaire-based subjective symptoms, TF break-up time, Schirmer test, and TF analysis in women working with computers and to analyze the effects of the oral supplementation with antioxidants/omega 3 fatty acids (A/ω3 in the OS outcomes. Women aged 40–65 years (n=148 were recruited at the Administrative Offices of Valencia (Spain and distributed into two age groups, 40–52 years (AGE1; n=87 and 53–65 years (AGE2; n=61, and then subdivided according to being (or not computer users (CUG; NCUG during the workday. Homogeneous subgroups were randomly assigned (or not to the daily intake of three pills of A/ω3 for three months. At baseline and at the end of follow-up, personalized interviews and ocular examination were done. Reflex tear samples were collected from the inferior meniscus and processed for a multiplexed particle-based flow cytometry assay to measure proinflammatory molecules. Statistics were performed using the SPSS 15.0 program. The OS pathology was clinically evident in the AGE1-CUG (33% versus the AGE2-CUG (64% of women. Significantly higher interleukins-1β and -6 tear levels were found in the AGE1 versus the AGE2 women employees (P=0.006 and P=0.001, resp., as well as in the CUG versus the NCUG (P=0.001 and P=0.000, resp.. Supplementation with A/ω3 positively influenced the OS pathology as manifested by the amelioration of the clinical signs/symptoms related to computer uses. Strategies involving a safe environment and oral micronutrient supplements may be managed within eye-care standards in older women.

  16. Transtendon, double-row, transosseous-equivalent arthroscopic repair of partial-thickness, articular-surface rotator cuff tears.

    Science.gov (United States)

    Dilisio, Matthew F; Miller, Lindsay R; Higgins, Laurence D

    2014-10-01

    Arthroscopic transtendinous techniques for the arthroscopic repair of partial-thickness, articular-surface rotator cuff tears offer the advantage of minimizing the disruption of the patient's remaining rotator cuff tendon fibers. In addition, double-row fixation of full-thickness rotator cuff tears has shown biomechanical advantages. We present a novel method combining these 2 techniques for transtendon, double-row, transosseous-equivalent arthroscopic repair of partial-thickness, articular-surface rotator cuff tears. Direct visualization of the reduction of the retracted articular tendon layer to its insertion on the greater tuberosity is the key to the procedure. Linking the medial-row anchors and using a double-row construct provide a stable repair that allows early shoulder motion to minimize the risk of postoperative stiffness.

  17. [Alterations in tears aqueous layer during cytostatics treatment].

    Science.gov (United States)

    Wojciechowska, Katarzyna; Wieckowska-Szakiel, Marzena; Rózalska, Barbara; Jurowski, Piotr

    2013-01-01

    The aim of the study was to evaluate tears secretion, pH and lysozyme activity in tears aqueous layer during chemotherapy in lung, breast and bowel cancer. 36 patients were enrolled to the study. Depending on the type of cancer and type of chemotherapy patients were divided into three groups. Group I (12 patients) diagnosed with non-small-cell lung cancer treated with PE schema (cisplatin, etoposide), Group II (12 patients) with breast cancer treated with FAC schema (fluorouracil, doxorubicin, cyclophosphamide), Group III (12 patients) with bowel cancer treated with FU/LV schema (fluorouracil, leucovorin). In all the patients: Schirmer's I test, pH measurements and lysozyme test were performed. Patients were examined before chemotherapy, after 2nd, 4th, 6th cycle. In group I and II lowering of tears secretion (p tears secretion (p tears film in all groups (p tears aqueous layer causing alterations of tears secretions. PH alterations depending on type of chemotherapy was observed. Lowering of lysozyme activity in tears was observed. All the deteriorations aggravate with duration of chemotherapy. Alterations of tears film parameters during chemotherapy may influence upon eye surface homeostasis and infectious complication. tears aqueous layer, Schirmer's test, lysozyme activity, tears pH.

  18. The Effect of Tear Supplementation on Ocular Surface Sensations during the Interblink Interval in Patients with Dry Eye.

    Directory of Open Access Journals (Sweden)

    Lóránt Dienes

    Full Text Available To investigate the characteristics of ocular surface sensations and corneal sensitivity during the interblink interval before and after tear supplementation in dry eye patients.Twenty subjects (41.88±14.37 years with dry eye symptoms were included in the dry eye group. Fourteen subjects (39.13±11.27 years without any clinical signs and/or symptoms of dry eye were included in the control group. Tear film dynamics was assessed by non-invasive tear film breakup time (NI-BUT in parallel with continuous recordings of ocular sensations during forced blinking. Corneal sensitivity to selective stimulation of corneal mechano-, cold and chemical receptors was assessed using a gas esthesiometer. All the measurements were made before and 5 min after saline and hydroxypropyl-guar (HP-guar drops.In dry eye patients the intensity of irritation increased rapidly after the last blink during forced blinking, while in controls there was no alteration in the intensity during the first 10 sec followed by an exponential increase. Irritation scores were significantly higher in dry eye patients throughout the entire interblink interval compared to controls (p0.05.Ocular surface irritation responses due to tear film drying are considerably increased in dry eye patients compared to normal subjects. Although tear supplementation improves the protective tear film layer, and thus reduce unpleasant sensory responses, the rapid rise in discomfort is still maintained and might be responsible for the remaining complaints of dry eye patients despite the treatment.

  19. Coupling Fluid and Solute Dynamics Within the Ocular Surface Tear Film: A Modelling Study of Black Line Osmolarity

    KAUST Repository

    Zubkov, V. S.

    2012-07-06

    We present a mathematical model describing the spatial distribution of tear film osmolarity across the ocular surface of a human eye during one blink cycle, incorporating detailed fluid and solute dynamics. Based on the lubrication approximation, our model comprises three coupled equations tracking the depth of the aqueous layer of the tear film, the concentration of the polar lipid, and the concentration of physiological salts contained in the aqueous layer. Diffusive boundary layers in the salt concentration occur at the thinnest regions of the tear film, the black lines. Thus, despite large Peclet numbers, diffusion ameliorates osmolarity around the black lines, but nonetheless is insufficient to eliminate the build-up of solute in these regions. More generally, a heterogeneous distribution of solute concentration is predicted across the ocular surface, indicating that measurements of lower meniscus osmolarity are not globally representative, especially in the presence of dry eye. Vertical saccadic eyelid motion can reduce osmolarity at the lower black line, raising the prospect that select eyeball motions more generally can assist in alleviating tear film hyperosmolarity. Finally, our results indicate that measured evaporative rates will induce excessive hyperosmolarity at the black lines, even for the healthy eye. This suggests that further evaporative retardation at the black lines, for instance due to the cellular glycocalyx at the ocular surface or increasing concentrations of mucus, will be important for controlling hyperosmolarity as the black line thins. © 2012 Society for Mathematical Biology.

  20. Dry eye evaluation and correlation analysis between tear film stability and corneal surface regularity after small incision lenticule extraction.

    Science.gov (United States)

    Zhang, Hui; Wang, Yan

    2017-09-22

    To investigate the dry eye after small incision lenticule extraction (SMILE) and explore the correlations between changes in the tear film stability, the tear secretion and the corneal surface regularity. Sixty-two eyes of 22 men and 13 women who underwent SMILE were included in this study. Corneal topography was measured to assess the index of surface variance (ISV) and the index of vertical asymmetry (IVA). Dry eye tests including subjective symptom questionnaire, tear breakup time (TBUT), corneal fluorescein staining and Schirmer's test (ST) were evaluated before and at 1 and 6 months postoperatively. TBUT was found to be significantly decreased from 9.8 ± 3.4 s preoperatively to 7.4 ± 3.8 s at 1 month and 6.5 ± 3.6 s at 6 months (both P short-TBUT type of dry eye. Corneal surface regularity indices might be helpful in the assessment of tear film stability following SMILE procedure.

  1. Tearing stability analysis of an axial surface flaw in thick-walled pressure vessels

    International Nuclear Information System (INIS)

    Zahoor, A.; Ghassemi, B.B.

    1991-01-01

    This paper presents two fracture mechanics models for evaluation of an axial surface flaw in pressure vessels. The surface flaw is located on the outside surface of the vessel. The first model assumes yielding of the remaining ligament directly ahead of the flaw. The second model assumes contained yielding ahead of the flaw and uses a linear elastic fracture mechanics solution. The former model is suitable for cases where the combination of material toughness, flaw size, and load is such that initiation of flaw growth follows ligament yielding. The latter model is suitable for low-toughness materials where initiation of crack growth and potential tearing instability may occur prior to the yielding of the ligament. Both models are suitable for thick-walled vessels. The paper discusses the applicability regime for both models. The models are then applied to a test vessel and the predicted failure pressure is compared against the pressure attained in the test. Results show that both models can be applied successfully. In particular, the contained yielding model when used with the plane-stress assumption can give reasonable predictions even for cases that involve yielding of the ligament. (orig.)

  2. Tearing stability analysis of an axial surface flaw in thick-walled pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Zahoor, A.; Ghassemi, B.B. (NOVETECH Corp., Rockville, MD (USA))

    1991-04-01

    This paper presents two fracture mechanics models for evaluation of an axial surface flaw in pressure vessels. The surface flaw is located on the outside surface of the vessel. The first model assumes yielding of the remaining ligament directly ahead of the flaw. The second model assumes contained yielding ahead of the flaw and uses a linear elastic fracture mechanics solution. The former model is suitable for cases where the combination of material toughness, flaw size, and load is such that initiation of flaw growth follows ligament yielding. The latter model is suitable for low-toughness materials where initiation of crack growth and potential tearing instability may occur prior to the yielding of the ligament. Both models are suitable for thick-walled vessels. The paper discusses the applicability regime for both models. The models are then applied to a test vessel and the predicted failure pressure is compared against the pressure attained in the test. Results show that both models can be applied successfully. In particular, the contained yielding model when used with the plane-stress assumption can give reasonable predictions even for cases that involve yielding of the ligament. (orig.).

  3. The tear turnover and tear clearance tests - a review.

    Science.gov (United States)

    Garaszczuk, Izabela K; Montes Mico, Robert; Iskander, D Robert; Expósito, Alejandro Cerviño

    2018-03-01

    The aim is to provide a summary of methods available for the assessment of tear turnover and tear clearance rates. The review defines tear clearance and tear turnover and describes their implication for ocular surface health. Additionally, it describes main types of techniques for measuring tear turnover, including fluorescein tear clearance tests, techniques utilizing electromagnetic spectrum and tracer molecule and novel experimental techniques utilizing optical coherence tomography and fluorescein profilometry. Areas covered: Internet databases (PubMed, Science Direct, Google Scholar) and most frequently cited references were used as a principal resource of information on tear turnover rate and tear clearance rate, presenting methodologies and equipment, as well as their definition and implications for the anterior eye surface health and function. Keywords used for data-search were as follows: tear turnover, tear clearance, fluorescein clearance, scintigraphy, fluorophotometry, tear flow, drainage, tear meniscus dynamics, Krehbiel flow and lacrimal functional unit. Expert commentary: After decades, the topic of tear turnover assessment has been reintroduced. Recently, new techniques have been developed to propose less invasive, less time consuming and simpler methodologies for the assessment of tear dynamics that have the potential to be utilized in clinical practice.

  4. Application of texture analysis in tear film surface assessment based on videokeratoscopy

    Directory of Open Access Journals (Sweden)

    David Alonso-Caneiro

    2013-10-01

    Conclusions: Texture analysis of videokeratoscopy images is applicable to study tear film anomalies in dry eye subjects. The proposed technique appears to have demonstrated its clinical relevance and utility.

  5. Effect of Omega-3 Fatty Acids Dietary Supplementation on Ocular Surface and Tear Film in Diabetic Patients with Dry Eye.

    Science.gov (United States)

    Georgakopoulos, Constantine D; Makri, Olga E; Pagoulatos, Dionisios; Vasilakis, Panagiotis; Peristeropoulou, Politimi; Kouli, Vasiliki; Eliopoulou, Maria I; Psachoulia, Caterina

    2017-01-01

    The objective of this study was to investigate the effect of dietary supplementation with omega-3 fatty acids on ocular surface and tear film in patients with type 2 diabetes suffering from dry eye. Thirty-six patients suffering from type 2 diabetes and moderate to severe dry eye syndrome were included in the study. Patients were assigned to receive omega-3 long-chain polyunsaturated fatty acids for 3 months. Tear film break-up time test, Schirmer-I test, and conjunctival impression cytology analysis were performed on all patients at baseline and after 1 and 3 months. The subjective symptoms of dry eye were evaluated with the Ocular Surface Disease Index (OSDI) questionnaire at the same time points. Patients' average age was 65.57 ± 4.27 years and the mean duration of diabetes was 14.85 ± 5.4 years. There was a statistically significant increase in Schirmer-I test results and tear break-up time score after 3 months of supplementary intake of omega-3 fatty acids compared to baseline (p dry eye syndrome in patients with type 2 diabetes.

  6. Distance-Based Tear Lactoferrin Assay on Microfluidic Paper Device Using Interfacial Interactions on Surface-Modified Cellulose.

    Science.gov (United States)

    Yamada, Kentaro; Henares, Terence G; Suzuki, Koji; Citterio, Daniel

    2015-11-11

    "Distance-based" detection motifs on microfluidic paper-based analytical devices (μPADs) allow quantitative analysis without using signal readout instruments in a similar manner to classical analogue thermometers. To realize a cost-effective and calibration-free distance-based assay of lactoferrin in human tear fluid on a μPAD not relying on antibodies or enzymes, we investigated the fluidic mobilities of the target protein and Tb(3+) cations used as the fluorescent detection reagent on surface-modified cellulosic filter papers. Chromatographic elution experiments in a tear-like sample matrix containing electrolytes and proteins revealed a collapse of attractive electrostatic interactions between lactoferrin or Tb(3+) and the cellulosic substrate, which was overcome by the modification of the paper surface with the sulfated polysaccharide ι-carrageenan. The resulting μPAD based on the fluorescence emission distance successfully analyzed 0-4 mg mL(-1) of lactoferrin in complex human tear matrix with a lower limit of detection of 0.1 mg mL(-1) by simple visual inspection. Assay results of 18 human tear samples including ocular disease patients and healthy volunteers showed good correlation to the reference ELISA method with a slope of 0.997 and a regression coefficient of 0.948. The distance-based quantitative signal and the good batch-to-batch fabrication reproducibility relying on printing methods enable quantitative analysis by simply reading out "concentration scale marks" printed on the μPAD without performing any calibration and using any signal readout instrument.

  7. Tear dynamics in healthy and dry eyes.

    Science.gov (United States)

    Cerretani, Colin F; Radke, C J

    2014-06-01

    Dry-eye disease, an increasingly prevalent ocular-surface disorder, significantly alters tear physiology. Understanding the basic physics of tear dynamics in healthy and dry eyes benefits both diagnosis and treatment of dry eye. We present a physiological-based model to describe tear dynamics during blinking. Tears are compartmentalized over the ocular surface; the blink cycle is divided into three repeating phases. Conservation laws quantify the tear volume and tear osmolarity of each compartment during each blink phase. Lacrimal-supply and tear-evaporation rates are varied to reveal the dependence of tear dynamics on dry-eye conditions, specifically tear osmolarity, tear volume, tear-turnover rate (TTR), and osmotic water flow. Predicted periodic-steady tear-meniscus osmolarity is 309 and 321 mOsM in normal and dry eyes, respectively. Tear osmolarity, volume, and TTR all match available clinical measurements. Osmotic water flow through the cornea and conjunctiva contribute 10 and 50% to the total tear supply in healthy and dry-eye conditions, respectively. TTR in aqueous-deficient dry eye (ADDE) is only half that in evaporative dry eye (EDE). The compartmental periodic-steady tear-dynamics model accurately predicts tear behavior in normal and dry eyes. Inclusion of osmotic water flow is crucial to match measured tear osmolarity. Tear-dynamics predictions corroborate the use of TTR as a clinical discriminator between ADDE and EDE. The proposed model is readily extended to predict the dynamics of aqueous solutes such as drugs or fluorescent tags.

  8. Antimicrobial compounds in tears.

    Science.gov (United States)

    McDermott, Alison M

    2013-12-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Tearing instabilities in turbulence

    International Nuclear Information System (INIS)

    Ishizawa, A.; Nakajima, N.

    2009-01-01

    Full text: Effects of micro-turbulence on tearing instabilities are investigated by numerically solving a reduced set of two-fluid equations. Micro-turbulence excites both large-scale and small-scale Fourier modes through energy transfer due to nonlinear mode coupling. The energy transfer to large scale mode does not directly excite tearing instability but it gives an initiation of tearing instability. When tearing instability starts to grow, the excited small scale mode plays an important role. The mixing of magnetic flux by micro-turbulence is the dominant factor of non-ideal MHD effect at the resonant surface and it gives rise to magnetic reconnection which causes tearing instability. Tearing instabilities were investigated against static equilibrium or flowing equilibrium so far. On the other hand, the recent progress of computer power allows us to investigate interactions between turbulence and coherent modes such as tearing instabilities in magnetically confined plasmas by means of direct numerical simulations. In order to investigate effects of turbulence on tearing instabilities we consider a situation that tearing mode is destabilized in a quasi-equilibrium including micro-turbulence. We choose an initial equilibrium that is unstable against kinetic ballooning modes and tearing instabilities. Tearing instabilities are current driven modes and thus they are unstable for large scale Fourier modes. On the other hand kinetic ballooning modes are unstable for poloidal Fourier modes that are characterized by ion Larmor radius. The energy of kinetic ballooning modes spreads over wave number space through nonlinear Fourier mode coupling. We present that micro-turbulence affects tearing instabilities in two different ways by three-dimensional numerical simulation of a reduced set of two-fluid equations. One is caused by energy transfer to large scale modes, the other is caused by energy transfer to small scale modes. The former is the excitation of initial

  10. Surface parameter characterization of surface vibrations in linear chains

    International Nuclear Information System (INIS)

    Majlis, N.; Selzer, S.; Puszkarski, H.; Diep-The-Hung

    1982-12-01

    We consider the vibrations of a linear monatomic chain with a complex surface potential defined by the surface pinning parameter a=Aesup(-i psi). It is found that in the case of a semi-infinite chain a is connected with the surface vibration wave number k=s+it by the exact relations: s=psi, t=lnA. We also show that the solutions found can be regarded as approximate ones (in the limit L>>1) for surface vibrations of a finite chain consisting of L atoms. (author)

  11. Assessment of Corneal and Tear Film Parameters in Rheumatoid Arthritis Patients Using Anterior Segment Spectral Domain Optical Coherence Tomography.

    Science.gov (United States)

    El-Fayoumi, Dina; Youssef, Maha Mohamed; Khafagy, Mohamed Mahmoud; Badr El Dine, Nashwa; Gaber, Wafaa

    2018-01-01

    To study the corneal changes in rheumatoid arthritis (RA) patients in vivo, using spectral domain anterior segment optical coherence tomography (AS-OCT). A case-control study was done on 43 RA patients and 40 controls. The disease activity score (DAS28-ESR) was calculated and all participants had lower tear meniscus, corneal thickness, and epithelial thickness evaluation using AS-OCT. The lower tear meniscus height (LTMH) and the lower tear meniscus area (LTMA) were significantly lower in the RA patients than in controls (p < 0.001). RA patients also had a significantly thinner central corneal thickness (p = 0.02) and their epithelium was found to be thinner in the superotemporal peripheral sector. The LTMH and LTMA are significantly reduced in RA patients, despite the absence of clinical diagnosis of dry eye. RA patients have thinner corneal thickness and epithelial thickness than controls, which did not correlate with either disease duration or activity.

  12. The Effect of Polar Lipids on Tear Film Dynamics

    KAUST Repository

    Aydemir, E.

    2010-06-17

    In this paper, we present a mathematical model describing the effect of polar lipids, excreted by glands in the eyelid and present on the surface of the tear film, on the evolution of a pre-corneal tear film. We aim to explain the interesting experimentally observed phenomenon that the tear film continues to move upward even after the upper eyelid has become stationary. The polar lipid is an insoluble surface species that locally alters the surface tension of the tear film. In the lubrication limit, the model reduces to two coupled non-linear partial differential equations for the film thickness and the concentration of lipid. We solve the system numerically and observe that increasing the concentration of the lipid increases the flow of liquid up the eye. We further exploit the size of the parameters in the problem to explain the initial evolution of the system. © 2010 Society for Mathematical Biology.

  13. Estimation of gloss from rough surface parameters

    Science.gov (United States)

    Simonsen, Ingve; Larsen, Åge G.; Andreassen, Erik; Ommundsen, Espen; Nord-Varhaug, Katrin

    2005-12-01

    Gloss is a quantity used in the optical industry to quantify and categorize materials according to how well they scatter light specularly. With the aid of phase perturbation theory, we derive an approximate expression for this quantity for a one-dimensional randomly rough surface. It is demonstrated that gloss depends in an exponential way on two dimensionless quantities that are associated with the surface randomness: the root-mean-square roughness times the perpendicular momentum transfer for the specular direction, and a correlation function dependent factor times a lateral momentum variable associated with the collection angle. Rigorous Monte Carlo simulations are used to access the quality of this approximation, and good agreement is observed over large regions of parameter space.

  14. Contributions of ocular surface components to matrix-metalloproteinases (MMP)-2 and MMP-9 in feline tears following corneal epithelial wounding.

    Science.gov (United States)

    Petznick, Andrea; Madigan, Michele C; Garrett, Qian; Sweeney, Deborah F; Evans, Margaret D M

    2013-01-01

    This study investigated ocular surface components that contribute to matrix-metalloproteinase (MMP)-2 and MMP-9 found in tears following corneal epithelial wounding. Laboratory short-haired cats underwent corneal epithelial debridement in one randomly chosen eye (n = 18). Eye-flush tears were collected at baseline and during various healing stages. Procedural control eyes (identical experimental protocol as wounded eyes except for wounding, n = 5) served as controls for tear analysis. MMP activity was analyzed in tears using gelatin zymography. MMP staining patterns were evaluated in ocular tissues using immunohistochemistry and used to determine MMP expression sites responsible for tear-derived MMPs. The proMMP-2 and proMMP-9 activity in tears was highest in wounded and procedural control eyes during epithelial migration (8 to 36 hours post-wounding). Wounded eyes showed significantly higher proMMP-9 in tears only during and after epithelial restratification (day 3 to 4 and day 7 to 28 post-wounding, respectively) as compared to procedural controls (pTears from wounded and procedural control eyes showed no statistical differences for pro-MMP-2 and MMP-9 (p>0.05). Immunohistochemistry showed increased MMP-2 and MMP-9 expression in the cornea during epithelial migration and wound closure. The conjunctival epithelium exhibited highest levels of both MMPs during wound closure, while MMP-9 expression was reduced in conjunctival goblet cells during corneal epithelial migration followed by complete absence of the cells during wound closure. The immunostaining for both MMPs was elevated in the lacrimal gland during corneal healing, with little/no change in the meibomian glands. Conjunctival-associated lymphoid tissue (CALT) showed weak MMP-2 and intense MMP-9 staining. Following wounding, migrating corneal epithelium contributed little to the observed MMP levels in tears. The major sources assessed in the present study for tear-derived MMP-2 and MMP-9 following

  15. Parameter optimization for surface flux transport models

    Science.gov (United States)

    Whitbread, T.; Yeates, A. R.; Muñoz-Jaramillo, A.; Petrie, G. J. D.

    2017-11-01

    Accurate prediction of solar activity calls for precise calibration of solar cycle models. Consequently we aim to find optimal parameters for models which describe the physical processes on the solar surface, which in turn act as proxies for what occurs in the interior and provide source terms for coronal models. We use a genetic algorithm to optimize surface flux transport models using National Solar Observatory (NSO) magnetogram data for Solar Cycle 23. This is applied to both a 1D model that inserts new magnetic flux in the form of idealized bipolar magnetic regions, and also to a 2D model that assimilates specific shapes of real active regions. The genetic algorithm searches for parameter sets (meridional flow speed and profile, supergranular diffusivity, initial magnetic field, and radial decay time) that produce the best fit between observed and simulated butterfly diagrams, weighted by a latitude-dependent error structure which reflects uncertainty in observations. Due to the easily adaptable nature of the 2D model, the optimization process is repeated for Cycles 21, 22, and 24 in order to analyse cycle-to-cycle variation of the optimal solution. We find that the ranges and optimal solutions for the various regimes are in reasonable agreement with results from the literature, both theoretical and observational. The optimal meridional flow profiles for each regime are almost entirely within observational bounds determined by magnetic feature tracking, with the 2D model being able to accommodate the mean observed profile more successfully. Differences between models appear to be important in deciding values for the diffusive and decay terms. In like fashion, differences in the behaviours of different solar cycles lead to contrasts in parameters defining the meridional flow and initial field strength.

  16. Upregulation of NLRP3 Inflammasome in the Tears and Ocular Surface of Dry Eye Patients.

    Directory of Open Access Journals (Sweden)

    Liangliang Niu

    Full Text Available To evaluate the mRNA and protein expressions of NLRP3 inflammasome and its downstream inflammatory factors in human dry eye.We recruited 54 patients with Sjögren's syndrome dry eye (SSDE, 50 patients with non-Sjögren's syndrome dry eye (NSSDE, and 46 healthy controls. Tear film breakup time (TBUT, Schirmer I test, and fluorescein staining (FL were performed on all subjects. Tear samples were obtained to analyze the inflammatory cytokine levels of IL-1β and IL-18 via enzyme-linked immunosorbent (ELISA. Conjunctival impression cytology (CIC specimens were collected to detect the mRNA expression of NLRP3, caspase-1, IL-1β, and IL-18 using quantitative RT-PCR, and the protein expression of NLRP3 and caspase-1 by Western blotting.NLRP3 mRNA expression showed higher levels in both dry eye groups compared with controls, with a comparably significant elevation in the SSDE group (relative 2.47-fold upregulation, p<0.05. NLRP3 protein expression was also increased in SSDE group (relative1.94-fold upregulation compared with the controls. mRNA expression of caspase-1 was significantly upregulated in both SSDE (relative 1.44-fold upregulation, p<0.05 and NSSDE (relative 1.32-fold upregulation, p<0.05. Procaspase-1 protein level was increased in SSDE (relative 1.84-fold upregulation and NSSDE (relative 1.12-fold upregulation versus controls; and caspase-1 protein expression was also increased in SSDE (relative 1.49-fold upregulation and NSSDE (relative 1.17-fold upregulation compared with the controls. The patients with SSDE and NSSDE had higher IL-1β and IL-18 mRNA values and protein expressions than the controls did. The relative mRNA expression of IL-1β upregulated 3.59-fold (p<0.001 in SSDE and 2.13-fold (p<0.01 in NSSDE compared with the controls. IL-1β protein level also showed significant upregulation in SSDE (p=0.01; vs. controls groups. IL-18 mRNA expression levels were significantly upregulated in the SSDE (relative 2.97-fold upregulation, p

  17. Effects of topical cyclosporine a plus artificial tears versus artificial tears treatment on conjunctival goblet cell density in dysfunctional tear syndrome.

    Science.gov (United States)

    Demiryay, Elvan; Yaylali, Volkan; Cetin, Ebru Nevin; Yildirim, Cem

    2011-09-01

    The aim was to compare the effects of topical cyclosporine A and artificial tears combination with artificial tears alone in patients with dysfunctional tear syndrome (DTS). Forty-two eyes of 42 patients with DTS were enrolled in the study. The inclusion criteria for the study were Schirmer I (without anesthesia) scores below 10 mm/5 min and tear film break-up time (BUT) below 10 sec. The patients were randomly divided into two groups. The study group (22 patients) underwent 0.05% cyclosporine A treatment twice a day and preservative-free artificial tears for four times a day for 4 months. The control group (20 patients) was administered only preservative-free artificial tears four times a day for 4 months. The BUT, Schirmer test scores, corneal fluorescein staining, conjunctival lissamine green staining, and goblet cell density derived by impression cytology were recorded before and after treatment in each group. In the study group, all parameters improved statistically significantly after treatment at the 4-month follow-up compared with the pretreatment values (Ptears treatment significantly increases goblet cell density, decreases the signs of DTS, and improves ocular surface health.

  18. Tears of Wine

    Science.gov (United States)

    Gugliotti, Marcos

    2004-01-01

    The unique occurrence of the upward motion of a thin film of wine, and its formation into drops inside the wall of a wine glass is explained. Evaporation of alcohol generates a surface tension gradient, moving the film of wine upwards on the internal sides of a wine glass, where it collects and forms into drops or tears.

  19. The Effect of Tear Supplementation with 0.15% Preservative-Free Zinc-Hyaluronate on Ocular Surface Sensations in Patients with Dry Eye.

    Science.gov (United States)

    Perényi, Kristóf; Dienes, Lóránt; Kornafeld, Anna; Kovács, Balázs; Kiss, Huba J; Szepessy, Zsuzsanna; Nagy, Zoltán Z; Barsi, Árpád; Acosta, M Carmen; Gallar, Juana; Kovács, Illés

    To evaluate the effect of tear supplementation with preservative free 0.15% zinc-hyaluronate on ocular surface sensations and corneal sensitivity in dry eye patients. Ocular surface sensations were assessed using the ocular surface disease index (OSDI) questionnaire and by recording ocular sensations during forced blinking in parallel with noninvasive tear film breakup time measurement in 20 eyes of 20 dry eye patients. Corneal sensitivity thresholds to selective stimulation of corneal mechano-, thermal- and chemical receptors were measured using the Belmonte gas esthesiometer. All baseline measurements were repeated after 1 month of treatment with 0.15% zinc-hyaluronate. After 1 month, a significant decrease in mean OSDI score (from 35.66 ± 12.36 to 15.03 ± 11.22; P  0.05). Prolonged use of 0.15% zinc-hyaluronate results in an improvement of tear film stability and a decrease of dry eye complaints. The decrease in corneal mechano-and polymodal receptor excitability suggests that zinc-hyaluronate helps to recover normal corneal sensitivity, and thus might have a beneficial additional effect on reducing ocular surface complaints in dry eye patients.

  20. The Long-Term Effects of Silicone Hydrogel Contact Lenses on the Ocular Surface and Tear Function Tests

    Directory of Open Access Journals (Sweden)

    Yelda Yıldız Taşcı

    2014-05-01

    Full Text Available Objectives: To evaluate the effects of three different silicone hydrogel contact lenses, i.e. Balafilcon A (Pure Vision, Bausch & Lomb, Senofilcon A (Acuvue Oasys, Johnson & Johnson, and Confilcon A (Biofinity, CooperVision, on ocular surface after one, three, and sıx months of wear. Materials and Methods: Silicone hydrogel contact lenses (SHCL were fitted to 58 patients (Balafilcon A to 40 eyes: Group 1, Senofilcon A to 42 eyes: Group 2, and Confilcon A to 34 eyes: Group 3 who have not used any contact lenses before. All groups were graded according to the Cornea and Contact Lens Research Unit’s grading score, and were performed ocular surface disease index scoring (OSDI, tear break-up time (BUT, and Schirmer 1 test. Results: The mean age was 22.45±5.96, 20.76±3.70, 21.00±3.84 years in Groups 1,2, and 3, respectively (p>0.05. While the increase in papillary hypertrophy as well as palpebral and bulbar hyperemia at 1st month in Group 1 and at 6th month at Group 2 were significant, there were no change in Group 3 with the use of SHCL (p0.05. In Group 3, the Schirmer test was lower than in Groups 1 and 2, which was statistically significant (p=0.048, p=0.003. Conclusion: Factors like lens material, modulus, the presence of an internal wetting agent, and water content play an important role in the effects of SHCL on the ocular surface. In this study, it is demonstrated that SHCL does not cause clinically significant dry eye. (Turk J Ophthalmol 2014; 44: 201-6

  1. Linear stability of tearing modes

    International Nuclear Information System (INIS)

    Cowley, S.C.; Kulsrud, R.M.; Hahm, T.S.

    1986-05-01

    This paper examines the stability of tearing modes in a sheared slab when the width of the tearing layer is much smaller than the ion Larmor radius. The ion response is nonlocal, and the quasineutrality retains its full integal form. An expansion procedure is introduced to solve the quasineutrality equation in powers of the width of the tearing layer over the ion Larmor radius. The expansion procedure is applied to the collisionless and semi-collisional tearing modes. The first order terms in the expansion we find to be strongly stabilizing. The physics of the mode and of the stabilization is discussed. Tearing modes are observed in experiments even though the slab theory predicts stability. It is proposed that these modes grow from an equilibrium with islands at the rational surfaces. If the equilibrium islands are wider than the ion Larmor radius, the mode is unstable when Δ' is positive

  2. High Temperature Surface Parameters for Solar Power

    National Research Council Canada - National Science Library

    Butler, C. F; Jenkins, R. J; Rudkin, R. L; Laughridge, F. I

    1960-01-01

    ... at a given distance from the sun. Thermal conversion efficiencies with a concentration ratio of 50 have been computed for each surface when exposed to solar radiation at the Earth's mean orbital radius...

  3. Optimization of surface roughness parameters in dry turning

    OpenAIRE

    R.A. Mahdavinejad; H. Sharifi Bidgoli

    2009-01-01

    Purpose: The precision of machine tools on one hand and the input setup parameters on the other hand, are strongly influenced in main output machining parameters such as stock removal, toll wear ratio and surface roughnes.Design/methodology/approach: There are a lot of input parameters which are effective in the variations of these output parameters. In CNC machines, the optimization of machining process in order to predict surface roughness is very important.Findings: From this point of view...

  4. Nowcasting Surface Meteorological Parameters Using Successive Correction Method

    National Research Council Canada - National Science Library

    Henmi, Teizi

    2002-01-01

    The successive correction method was examined and evaluated statistically as a nowcasting method for surface meteorological parameters including temperature, dew point temperature, and horizontal wind vector components...

  5. Ocular surface and tear film status among contact lens wearers and non-wearers who use VDT at work: comparing three different lens types.

    Science.gov (United States)

    Tauste, Ana; Ronda, Elena; Baste, Valborg; Bråtveit, Magne; Moen, Bente E; Seguí Crespo, María-Del-Mar

    2018-04-01

    To analyze differences in the ocular surface appearance and tear film status of contact lens wearers and non-wearers in a group of visual display terminals (VDT) workers and additionally to assess differences between lens materials. Cross-sectional study of 236 office workers, of whom 92 were contact lens wearers. Workers provided information on their contact lenses (conventional hydrogel, silicone hydrogel or rigid gas permeable lenses) and exposure to VDT at work. Ocular surface and tear film status were determined by the presence of bulbar, limbal and lid redness, lid roughness and corneal staining type, and by Schirmer's and tear break-up time tests (TBUT). A generalized linear model was used to calculate the crude (cRR) and age- and sex-adjusted (aRR) relative risk to measure the association between ocular surface and tear film abnormalities and contact lens use and type. The aRR of ocular surface abnormalities was higher in contact lens wearers compared to non-wearers: bulbar redness (aRR 1.69; 95% CI 1.25-2.30), limbal redness (aRR 2.87; 1.88-4.37), lid redness (aRR 2.53; 1.35-4.73) and lid roughness (aRR 7.03; 1.31-37.82). VDT exposure > 4 h/day increased wearers' risk of limbal and lid redness. Conventional hydrogel wearers had the highest risk of ocular surface abnormalities, followed by silicone hydrogel wearers. Both contact and non-contact lens wearers had a high prevalence of altered TBUT (77.3 and 75.7% respectively) and Schirmer (51.8 and 41.3%). Regular contact lens use during VDT exposure at work increases risk of bulbar, limbal and lid redness, and lid roughness, especially in soft contact lens wearers. The high prevalence of altered TBUT and Schirmer's results in all participants suggests that VDT use greatly affects tear film characteristics.

  6. Transtendon rotator-cuff repair of partial-thickness articular surface tears can lead to medial rotator-cuff failure

    Directory of Open Access Journals (Sweden)

    Woods TC

    2014-06-01

    Full Text Available Tom C Woods,4 Michael J Carroll,1 Atiba A Nelson,2 Kristie D More,2 Randa Berdusco,1 Stephen Sohmer,3 Richard S Boorman,1,2 Ian KY Lo1,21Department of Surgery, 2Sport Medicine Centre, University of Calgary, Calgary, AB, Canada; 3Department of Orthopaedics, University of British Columbia, Vancouver, 4St Joseph's Hospital, Comox, BC, CanadaPurpose: The purpose of this study was to evaluate clinical and anatomic outcomes of patients following transtendon rotator-cuff repair of partial articular supraspinatus tendon avulsion (PASTA lesions.Patients and methods: Patients in the senior author's practice who had isolated PASTA lesions treated by transtendon rotator-cuff repair were included (n=8 and retrospectively reviewed. All patients were evaluated preoperatively and at a mean of 21.2 months (±9.7 months postoperatively using standardized clinical evaluation (physical exam, American Shoulder and Elbow Surgeons, and Simple Shoulder Test. All patients underwent postoperative imaging with a magnetic resonance imaging arthrogram.Results: There was a significant improvement in American Shoulder and Elbow Surgeons (42.7±17.5 to 86.9±25.2 and Simple Shoulder Test (4.6±3.2 to 10.1±3.8 scores from pre- to postoperative, respectively. Postoperative imaging demonstrated full-thickness medial cuff tearing in seven patients, and one patient with a persistent partial articular surface defect.Conclusion: Transtendon repair of PASTA lesions may lead to improvements in clinical outcome. However, postoperative imaging demonstrated a high incidence of full-thickness rotator-cuff defects following repair.Keywords: rotator cuff, PASTA lesion, transtendon repair

  7. Pele's tears and spheres

    Science.gov (United States)

    Porritt, L. A.; Quane, S.; Russell, K.

    2011-12-01

    Pele's tears are a well known curiosity commonly associated with low viscosity basaltic explosive eruptions. However, these pyroclasts are rarely studied in detail and there is no full explanation for their formation. These intriguing pyroclasts have smooth glassy surfaces, vesiculated interiors, and fluidal morphologies tending towards droplets and then spheres as they decrease in size to Pele's tears from the 1959 fire-fountaining eruption of Kilauea Iki involving size and density measurements. Using thin section and SEM analysis we also consider their internal and external morphologies, porosity and bubble size distributions, and surface textures. Finally we consider the mechanisms of magma fragmentation, timescales of relaxation, and cooling rates that are responsible for their formation.

  8. Diquafosol sodium ophthalmic solution for the treatment of dry eye: clinical evaluation and biochemical analysis of tear composition.

    Science.gov (United States)

    Shigeyasu, Chika; Yamada, Masakazu; Akune, Yoko; Tsubota, Kazuo

    2015-11-01

    To evaluate the clinical efficacy of 3% diquafosol sodium ophthalmic solution for dry eye, and to analyze the concentration of tear proteins and mucin-like substances after the treatment. Fifty eyes of 25 patients with dry eye syndrome were prospectively enrolled. The patients were treated with diquafosol solution at a dose of 1 drop in each eye 6 times daily for 4 weeks. The parameters of clinical efficacy were tear osmolarity, tear breakup time (BUT), fluorescein staining scores for the cornea and conjunctiva, Schirmer test values, and subjective symptoms evaluated using the ocular surface disease index (OSDI). Tears collected with Schirmer test strips were analyzed by high-performance liquid chromatography, and the concentrations of the total protein and the 4 major tear proteins, namely, secretory IgA, lactoferrin, lipocalin-1, lysozyme, and N-acetyl-neuraminic acid (Neu5Ac), were measured. Neu5Ac is a major sialic acid, a marker of secretory mucins. The BUT, keratoconjunctival staining scores, and Schirmer test values were improved with statistical significance after the treatment with diquafosol solution, while changes in the other parameters, including tear osmolarity, corneal staining scores, and OSDI scores were not significant. The Neu5Ac concentration was significantly increased, which was not accompanied by changes in tear proteins. Topical application of diquafosol significantly improved the clinical parameters of the BUT, keratoconjunctival staining scores, and Schirmer test values and was accompanied by increased sialic acid content in the tears of patients with dry eye.

  9. Meniscus Tears (For Teens)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Meniscus Tears KidsHealth / For Teens / Meniscus Tears What's in this ... surgery to fix it. What Is a Meniscus Tear? Your knee is made up of three bones: ...

  10. Divalent cations in tears, and their influence on tear film stability in humans and rabbits.

    Science.gov (United States)

    Wei, Xiaojia Eric; Markoulli, Maria; Millar, Thomas J; Willcox, Mark D P; Zhao, Zhenjun

    2012-06-05

    Reduced tear film stability is reported to contribute to dry eye. Rabbits are known to have a more stable tear film than humans. Thus, we sought to examine the tears of rabbits and humans for metal cations, and to test how they influence tear film stability. Tears were collected from 10 healthy humans and 6 rabbits. Tear osmolality was measured by vapor pressure osmometer, and metals analyzed using inductively coupled plasma (ICP) mass spectrometry or ICP atomic emission spectroscopy. The influence of divalent cations on tears was analyzed by measuring surface tension using the Langmuir trough in vitro, using different concentrations of cations in the subphase, and grading the tear break-up in rabbits in vivo after instillation of chelating agents. Rabbit tears had a higher osmolality compared to humans. Major metals did not differ between species; however, rabbits had higher levels of Mg(2+) (1.13 vs. 0.39 mM) and Ca(2+) (0.75 vs. 0.36 mM). In rabbit tears in vitro, diminishing divalent cations resulted in a decrease in the maximum surface pressure from 37 to 30 mN/m. In vivo, an increase in the amount of tear film that was broken-up was found. In contrast, when changing divalent cation concentrations in human tears, the maximum surface pressure remained at 26 mN/m. The normal osmolality of rabbit tears is significantly higher than that in humans. While divalent cations had little influence on human tears, they appear to have an important role in maintaining tear film stability in rabbits.

  11. Peripheral Neuropathy and Tear Film Dysfunction in Type 1 Diabetes Mellitus

    Directory of Open Access Journals (Sweden)

    Stuti L. Misra

    2014-01-01

    Full Text Available Purpose. To compare tear film metrics in patients with type 1 diabetes mellitus (DM and healthy controls and investigate the association between peripheral neuropathy and ocular surface quality. Methods. Dry eye symptoms were quantified in 53 patients with type 1 DM and 40 age-matched controls. Ocular examination included tear film lipid layer thickness grading, tear film stability and quantity measurement, and retinal photography. DM individuals additionally underwent a detailed neuropathy assessment. Results. Neither mean age nor dry eye symptom scores differed significantly between the DM and control groups (P=0.12 and P=0.33, resp.. Tear lipid thickness (P=0.02, stability (P<0.0001, and quantity (P=0.01 were significantly lower in the DM group. Corneal sensitivity was also reduced in the DM group (P<0.001 and tear film stability was inversely associated with total neuropathy score (r=-0.29, P=0.03. Conclusion. The DM group exhibited significantly reduced tear film stability, secretion, and lipid layer quality relative to the age-matched control group. The negative correlation between tear film parameters and total neuropathy score suggests that ocular surface abnormalities occur in parallel with diabetic peripheral neuropathy.

  12. Plasma parameters of the cathode spot explosive electron emission cell obtained from the model of liquid-metal jet tearing and electrical explosion

    Science.gov (United States)

    Tsventoukh, M. M.

    2018-05-01

    A model has been developed for the explosive electron emission cell pulse of a vacuum discharge cathode spot that describes the ignition and extinction of the explosive pulse. The pulse is initiated due to hydrodynamic tearing of a liquid-metal jet which propagates from the preceding cell crater boundary and draws the ion current from the plasma produced by the preceding explosion. Once the jet neck has been resistively heated to a critical temperature (˜1 eV), the plasma starts expanding and decreasing in density, which corresponds to the extinction phase. Numerical and analytical solutions have been obtained that describe both the time behavior of the pulse plasma parameters and their average values. For the cell plasma, the momentum per transferred charge has been estimated to be some tens of g cm/(s C), which is consistent with the known measurements of ion velocity, ion erosion rate, and specific recoil force. This supports the model of the pressure-gradient-driven plasma acceleration mechanism for the explosive cathode spot cells. The ohmic electric field within the explosive current-carrying plasma has been estimated to be some tens of kV/cm, which is consistent with the known experimental data on cathode potential fall and explosive cell plasma size. This supports the model that assumes the ohmic nature of the cathode potential fall in a vacuum discharge.

  13. A global data set of land-surface parameters

    International Nuclear Information System (INIS)

    Claussen, M.; Lohmann, U.; Roeckner, E.; Schulzweida, U.

    1994-01-01

    A global data set of land surface parameters is provided for the climate model ECHAM developed at the Max-Planck-Institut fuer Meteorologie in Hamburg. These parameters are: background (surface) albedo α, surface roughness length z 0y , leaf area index LAI, fractional vegetation cover or vegetation ratio c y , and forest ratio c F . The global set of surface parameters is constructed by allocating parameters to major exosystem complexes of Olson et al. (1983). The global distribution of ecosystem complexes is given at a resolution of 0.5 0 x 0.5 0 . The latter data are compatible with the vegetation types used in the BIOME model of Prentice et al. (1992) which is a potential candidate of an interactive submodel within a comprehensive model of the climate system. (orig.)

  14. Variability of surface meteorological parameters over the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Fernandes, A.A

    different parameters shows that the sea surface temperature and air temperature are positively and significantly correlated over the study area. A similar relationship is found between wind speed and cloudiness amount. Wind speed and cloudiness...

  15. Post-blink tear film dynamics in healthy and dry eyes during spontaneous blinking.

    Science.gov (United States)

    Szczesna-Iskander, Dorota H

    2018-01-01

    The aim was to investigate the dynamics of post-blink tear film leveling in natural blinking conditions (NBC) for healthy subjects and those diagnosed with dry eye syndrome (DES) and to relate this phase to the tear film surface quality (TFSQ) before the following blink. The study included 19 healthy persons and 10 with dry eye, grouped according to symptoms and signs observed during examination. Lateral shearing interferometry was used to examine TFSQ. Post-blink tear film dynamics was modeled by an exponential function, characterized by the decay parameter b, and a constant, describing the level of the stabilized TFSQ. Pre-next-natural-blink TFSQ dynamics was modeled with a linear trend, described by a parameter A. The post-blink tear film dynamics reached its plateau at a significantly (P = 0.006) lower level in the normal tear film group than in the dry eye group. The median exponential decay parameter b was statistically significantly higher for the control group than for the DES group, P = 0.026. The parameter b calculated for each interblink interval was significantly correlated with the corresponding parameter A (Spearman's R = 0.35; P film fluorescein break-up time for each subject was also found (R = 0.41, P = 0.029). Significantly faster leveling of post-natural-blink tear film was observed in the group with DES than in healthy eyes. This dynamic was correlated with the pre-next-natural-blink TFSQ and tear film stability. The results of this pilot study support previous works that advocate the importance of polar lipids in the mechanism of tear film lipid spreading. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. TFOS DEWS II Tear Film Report.

    Science.gov (United States)

    Willcox, Mark D P; Argüeso, Pablo; Georgiev, Georgi A; Holopainen, Juha M; Laurie, Gordon W; Millar, Tom J; Papas, Eric B; Rolland, Jannick P; Schmidt, Tannin A; Stahl, Ulrike; Suarez, Tatiana; Subbaraman, Lakshman N; Uçakhan, Omür Ö; Jones, Lyndon

    2017-07-01

    The members of the Tear Film Subcommittee reviewed the role of the tear film in dry eye disease (DED). The Subcommittee reviewed biophysical and biochemical aspects of tears and how these change in DED. Clinically, DED is characterized by loss of tear volume, more rapid breakup of the tear film and increased evaporation of tears from the ocular surface. The tear film is composed of many substances including lipids, proteins, mucins and electrolytes. All of these contribute to the integrity of the tear film but exactly how they interact is still an area of active research. Tear film osmolarity increases in DED. Changes to other components such as proteins and mucins can be used as biomarkers for DED. The Subcommittee recommended areas for future research to advance our understanding of the tear film and how this changes with DED. The final report was written after review by all Subcommittee members and the entire TFOS DEWS II membership. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Artificial tears potpourri: a literature review

    Directory of Open Access Journals (Sweden)

    Moshirfar M

    2014-07-01

    Full Text Available Majid Moshirfar,1 Kasey Pierson,2,* Kamalani Hanamaikai,3,* Luis Santiago-Caban,1 Valliammai Muthappan,1 Samuel F Passi11Department of Ophthalmology, John A Moran Eye Center, University of Utah, Salt Lake City, UT, USA; 2University of Arizona College of Medicine, Phoenix, Phoenix, AZ, USA; 3A T Still University, School of Osteopathic Medicine in Arizona, Mesa, AZ, USA *These authors contributed equally to this work Abstract: Numerous brands and types of artificial tears are available on the market for the treatment of dysfunctional tear syndrome. Past literature has focused on comparing the components of these products on patient’s clinical improvement. The wide array of products on the market presents challenges to both clinicians and patients when trying to choose between available tear replacement therapies. Different formulations affect patients based on etiology and severity of disease. In order to provide an unbiased comparison between available tear replacement therapies, we conducted a literature review of existing studies and National Institutes of Health clinical trials on commercially available, brand name artificial tears. Outcomes evaluated in each study, as well as the percent of patients showing clinical and symptomatic improvement, were analyzed. Fifty-one studies evaluating different brands of artificial tears, and their efficacy were identified. Out of the 51 studies, 18 were comparison studies testing brand name artificial tears directly against each other. Nearly all formulations of artificial tears provided significant benefit to patients with dysfunctional tear syndrome, but some proved superior to others. From the study data, a recommended treatment flowchart was derived. Keywords: dry eye, tear film, dysfunctional tear syndrome, ophthalmic lubricant, artificial tears, lipid layer, tear osmolarity, TBUT, Systane®, Refresh®, Blink®, GenTeal®, Soothe®, Lacrisert®, ocular surface inflammatory disease, Sjogren

  18. A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye

    KAUST Repository

    Gaffney, E.A.

    2010-01-01

    Tear hyperosmolarity is thought to play a key role in the mechanism of dry eye, a common symptomatic condition accompanied by visual disturbance, tear film instability, inflammation and damage to the ocular surface. We have constructed a model for the mass and solute balance of the tears, with parameter estimation based on extensive data from the literature which permits the influence of tear evaporation, lacrimal flux and blink rate on tear osmolarity to be explored. In particular the nature of compensatory events has been estimated in aqueous-deficient (ADDE) and evaporative (EDE) dry eye. The model reproduces observed osmolarities of the tear meniscus for the healthy eye and predicts a higher concentration in the tear film than meniscus in normal and dry eye states. The differential is small in the normal eye, but is significantly increased in dry eye, especially for the simultaneous presence of high meniscus concentration and low meniscus radius. This may influence the interpretation of osmolarity values obtained from meniscus samples since they need not fully reflect potential damage to the ocular surface caused by tear film hyperosmolarity. Interrogation of the model suggests that increases in blink rate may play a limited role in compensating for a rise in tear osmolarity in ADDE but that an increase in lacrimal flux, together with an increase in blink rate, may delay the development of hyperosmolarity in EDE. Nonetheless, it is predicted that tear osmolarity may rise to much higher levels in EDE than ADDE before the onset of tear film breakup, in the absence of events at the ocular surface which would independently compromise tear film stability. Differences in the predicted responses of the pre-ocular tears in ADDE compared to EDE or hybrid disease to defined conditions suggest that no single, empirically-accessible variable can act as a surrogate for tear film concentration and the potential for ocular surface damage. This emphasises the need to measure

  19. A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye.

    Science.gov (United States)

    Gaffney, E A; Tiffany, J M; Yokoi, N; Bron, A J

    2010-01-01

    Tear hyperosmolarity is thought to play a key role in the mechanism of dry eye, a common symptomatic condition accompanied by visual disturbance, tear film instability, inflammation and damage to the ocular surface. We have constructed a model for the mass and solute balance of the tears, with parameter estimation based on extensive data from the literature which permits the influence of tear evaporation, lacrimal flux and blink rate on tear osmolarity to be explored. In particular the nature of compensatory events has been estimated in aqueous-deficient (ADDE) and evaporative (EDE) dry eye. The model reproduces observed osmolarities of the tear meniscus for the healthy eye and predicts a higher concentration in the tear film than meniscus in normal and dry eye states. The differential is small in the normal eye, but is significantly increased in dry eye, especially for the simultaneous presence of high meniscus concentration and low meniscus radius. This may influence the interpretation of osmolarity values obtained from meniscus samples since they need not fully reflect potential damage to the ocular surface caused by tear film hyperosmolarity. Interrogation of the model suggests that increases in blink rate may play a limited role in compensating for a rise in tear osmolarity in ADDE but that an increase in lacrimal flux, together with an increase in blink rate, may delay the development of hyperosmolarity in EDE. Nonetheless, it is predicted that tear osmolarity may rise to much higher levels in EDE than ADDE before the onset of tear film breakup, in the absence of events at the ocular surface which would independently compromise tear film stability. Differences in the predicted responses of the pre-ocular tears in ADDE compared to EDE or hybrid disease to defined conditions suggest that no single, empirically-accessible variable can act as a surrogate for tear film concentration and the potential for ocular surface damage. This emphasises the need to measure

  20. Interferometric characterization of tear film dynamics

    Science.gov (United States)

    Primeau, Brian Christopher

    The anterior refracting surface of the eye is the thin tear film that forms on the surface of the cornea. When a contact lens is on worn, the tear film covers the contact lens as it would a bare cornea, and is affected by the contact lens material properties. Tear film irregularity can cause both discomfort and vision quality degradation. Under normal conditions, the tear film is less than 10 microns thick and the thickness and topography change in the time between blinks. In order to both better understand the tear film, and to characterize how contact lenses affect tear film behavior, two interferometers were designed and built to separately measure tear film behavior in vitro and in vivo. An in vitro method of characterizing dynamic fluid layers applied to contact lenses mounted on mechanical substrates has been developed using a phase-shifting Twyman-Green interferometer. This interferometer continuously measures light reflected from the surface of the fluid layer, allowing precision analysis of the dynamic fluid layer. Movies showing this fluid layer behavior can be generated. The fluid behavior on the contact lens surface is measured, allowing quantitative analysis beyond what typical contact angle or visual inspection methods provide. The in vivo interferometer is a similar system, with additional modules included to provide capability for human testing. This tear film measurement allows analysis beyond capabilities of typical fluorescein visual inspection or videokeratometry and provides better sensitivity and resolution than shearing interferometry methods.

  1. Reducing surface roughness by optimising the turning parameters

    Directory of Open Access Journals (Sweden)

    Senthil Kumar, K.

    2013-08-01

    Full Text Available Modern manufacturers worldwide look for the cheapest quality-manufactured machined components to compete in the market. Good surface quality is desired for the proper functioning of the parts produced. The surface quality is influenced by the cutting speed, feed rate, depth of cut, and many other parameters. In this paper, the Taguchi method a powerful tool to design optimisation for quality is used to find the optimal machining parameters for the turning operation. An orthogonal array, the signal-to-noise (S/N ratio, and the analysis of variance (ANOVA are employed to investigate the machining characteristics of super duplex stainless steel bars using uncoated carbide cutting tools. The effect of machining parameters on surface roughness was discovered. Confirmation tests were conducted at optimal conditions to compare the experimental results with the predicted values.

  2. A Controlled Study on the Correlation between Tear Film Volume and Tear Film Stability in Diabetic Patients.

    Science.gov (United States)

    Eissa, Iman M; Khalil, Noha M; El-Gendy, Heba A

    2016-01-01

    Purpose. To assess the tear film quantity and correlate it with the quality and stability of the tear film in diabetics and compare them to age matched controls. Introduction. Diabetes affects tear film parameters in multiple ways. Poor metabolic control and neuropathy are postulated factors. To further understand how diabetes affects tear film parameters this study was conducted. Subjects and Methods. Tear meniscus height was measured by anterior segment OCT, along with tear thinning time, a subtype of noninvasive tear break-up time, and blinking rate per minute which were all recorded for 22 diabetic patients. Correlations between these tear film parameters were studied and then compared to 16 age matched controls. Results. A statistically significant difference was found in blinking rate between the diabetic and the control group (P = 0.002), with higher blinking rate among diabetics. All tear film parameters were negatively correlated with duration of diabetes. A positive correlation was found between tear film volume and stability. Conclusion. Diabetes affects the tear film in various ways. Diabetics should be examined for dry eye signs even in absence of symptoms which may be masked by associated neuropathy. Duration of diabetes has an impact on tear film status.

  3. A Controlled Study on the Correlation between Tear Film Volume and Tear Film Stability in Diabetic Patients

    Directory of Open Access Journals (Sweden)

    Iman M. Eissa

    2016-01-01

    Full Text Available Purpose. To assess the tear film quantity and correlate it with the quality and stability of the tear film in diabetics and compare them to age matched controls. Introduction. Diabetes affects tear film parameters in multiple ways. Poor metabolic control and neuropathy are postulated factors. To further understand how diabetes affects tear film parameters this study was conducted. Subjects and Methods. Tear meniscus height was measured by anterior segment OCT, along with tear thinning time, a subtype of noninvasive tear break-up time, and blinking rate per minute which were all recorded for 22 diabetic patients. Correlations between these tear film parameters were studied and then compared to 16 age matched controls. Results. A statistically significant difference was found in blinking rate between the diabetic and the control group (P=0.002, with higher blinking rate among diabetics. All tear film parameters were negatively correlated with duration of diabetes. A positive correlation was found between tear film volume and stability. Conclusion. Diabetes affects the tear film in various ways. Diabetics should be examined for dry eye signs even in absence of symptoms which may be masked by associated neuropathy. Duration of diabetes has an impact on tear film status.

  4. Bifurcation of steady tearing states

    International Nuclear Information System (INIS)

    Saramito, B.; Maschke, E.K.

    1985-10-01

    We apply the bifurcation theory for compact operators to the problem of the nonlinear solutions of the 3-dimensional incompressible visco-resistive MHD equations. For the plane plasma slab model we compute branches of nonlinear tearing modes, which are stationary for the range of parameters investigated up to now

  5. Statistics of ductile fracture surfaces: the effect of material parameters

    DEFF Research Database (Denmark)

    Ponson, Laurent; Cao, Yuanyuan; Bouchaud, Elisabeth

    2013-01-01

    distributed. The three dimensional analysis permits modeling of a three dimensional material microstructure and of the resulting three dimensional stress and deformation states that develop in the fracture process region. Material parameters characterizing void nucleation are varied and the statistics...... of the resulting fracture surfaces is investigated. All the fracture surfaces are found to be self-affine over a size range of about two orders of magnitude with a very similar roughness exponent of 0.56 ± 0.03. In contrast, the full statistics of the fracture surfaces is found to be more sensitive to the material...

  6. Packing parameters effect on injection molding of polypropylene nanostructured surfaces

    DEFF Research Database (Denmark)

    Calaon, Matteo; Tosello, Guido; Hansen, Hans Nørgaard

    2012-01-01

    having a diameter of 500 nm was employed. The tool insert surface was produced using chemical-based-batch techniques such aluminum anodization and nickel electroplating. During the injection molding process, polypropylene (PP) was employed as material and packing phase parameters (packing time, packing...

  7. One-parameter family of solitons from minimal surfaces

    Indian Academy of Sciences (India)

    solitons arising from a one parameter family of minimal surfaces. The process enables us to generate a new solution of the B–I equation from a given complex solution of a special type (which are abundant). We illustrate this with many examples. We find that the action or the energy of this family of solitons remains invariant ...

  8. Duplex Tear Film Evaporation Analysis.

    Science.gov (United States)

    Stapf, M R; Braun, R J; King-Smith, P E

    2017-12-01

    Tear film thinning, hyperosmolarity, and breakup can cause irritation and damage to the human eye, and these form an area of active investigation for dry eye syndrome research. Recent research demonstrates that deficiencies in the lipid layer may cause locally increased evaporation, inducing conditions for breakup. In this paper, we explore the conditions for tear film breakup by considering a model for tear film dynamics with two mobile fluid layers, the aqueous and lipid layers. In addition, we include the effects of osmosis, evaporation as modified by the lipid, and the polar portion of the lipid layer. We solve the system numerically for reasonable parameter values and initial conditions and analyze how shifts in these cause changes to the system's dynamics.

  9. Rotator cuff tears noncontrast MRI compared to MR arthrography

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ji Hyun; Yoon, Young Cheol [Sungkyunkwan University, School of Medicine, Department of Radiology, Samsung Medical Center, Gangnam-gu, Seoul (Korea, Republic of); Jung, Jee Young [Chungang University School of Medicine, Department of Radiology, Chungang University Hospital, Seoul (Korea, Republic of); Yoo, Jae Chul [Sungkyunkwan University, School of Medicine, Department of Orthopedic Surgery, Samsung Medical Center, Seoul (Korea, Republic of)

    2015-12-15

    To compare the accuracy of indirect magnetic resonance arthrography and noncontrast magnetic resonance imaging for diagnosing rotator cuff tears. In total, 333 patients who underwent noncontrast magnetic resonance imaging or indirect magnetic resonance arthrography were included retrospectively. Two musculoskeletal radiologists evaluated the images for the presence of supraspinatus-infraspinatus and subscapularis tendon tears. The overall diagnostic performance was calculated using the arthroscopic findings as the reference standard. Statistical differences between the diagnostic performances of the two methods were analyzed. Ninety-six and 237 patients who underwent noncontrast magnetic resonance imaging and indirect magnetic resonance arthrography were assigned into groups A and B, respectively. Sensitivity for diagnosing articular-surface partial-thickness supraspinatus-infraspinatus tendon tear was slightly higher in group B than in group A. Statistical significance was confirmed by multivariate analysis using the generalized estimating equation (p = 0.046). The specificity for diagnosing subscapularis tendon tear (85 % vs. 68 %, p = 0.012) and grading accuracy (57 % vs. 40 %, p = 0.005) was higher in group B than in group A; the differences were statistically significant for one out of two readers. Univariate analysis using the generalized estimating equation showed that the accuracy for diagnosing subscapularis tendon tear in group B was higher than in group A (p = 0.042). There were no statistically significant differences between the diagnostic performances of both methods for any other parameters. Indirect magnetic resonance arthrography may facilitate more accurate diagnosis and grading of subscapularis tendon tears compared with noncontrast magnetic resonance imaging. (orig.)

  10. Rotator cuff tears noncontrast MRI compared to MR arthrography

    International Nuclear Information System (INIS)

    Lee, Ji Hyun; Yoon, Young Cheol; Jung, Jee Young; Yoo, Jae Chul

    2015-01-01

    To compare the accuracy of indirect magnetic resonance arthrography and noncontrast magnetic resonance imaging for diagnosing rotator cuff tears. In total, 333 patients who underwent noncontrast magnetic resonance imaging or indirect magnetic resonance arthrography were included retrospectively. Two musculoskeletal radiologists evaluated the images for the presence of supraspinatus-infraspinatus and subscapularis tendon tears. The overall diagnostic performance was calculated using the arthroscopic findings as the reference standard. Statistical differences between the diagnostic performances of the two methods were analyzed. Ninety-six and 237 patients who underwent noncontrast magnetic resonance imaging and indirect magnetic resonance arthrography were assigned into groups A and B, respectively. Sensitivity for diagnosing articular-surface partial-thickness supraspinatus-infraspinatus tendon tear was slightly higher in group B than in group A. Statistical significance was confirmed by multivariate analysis using the generalized estimating equation (p = 0.046). The specificity for diagnosing subscapularis tendon tear (85 % vs. 68 %, p = 0.012) and grading accuracy (57 % vs. 40 %, p = 0.005) was higher in group B than in group A; the differences were statistically significant for one out of two readers. Univariate analysis using the generalized estimating equation showed that the accuracy for diagnosing subscapularis tendon tear in group B was higher than in group A (p = 0.042). There were no statistically significant differences between the diagnostic performances of both methods for any other parameters. Indirect magnetic resonance arthrography may facilitate more accurate diagnosis and grading of subscapularis tendon tears compared with noncontrast magnetic resonance imaging. (orig.)

  11. Influence of Ophthalmic Solutions on Tear Components.

    Science.gov (United States)

    Shigeyasu, Chika; Yamada, Masakazu; Akune, Yoko

    2016-11-01

    Tear fluids are a mixture of secretions derived from lacrimal glands, accessory lacrimal glands, conjunctiva, and meibomian glands. Compositional changes to tears occur in the normal state and during ocular surface disease, such as dry eye conditions. We have investigated compositional changes to tears after topical application of ophthalmic solutions, with regard to tear-specific proteins (secretory immunoglobulin A, lactoferrin, lipocalin-1, and lysozyme) and ocular surface mucin in normal and dry eye conditions using high-performance liquid chromatography. After application of saline solution (0.9% sodium chloride) in normal subjects, transient but significant decreases in all tear components were observed. The recovery of protein concentrations took up to 30 minutes and lasted longer when the saline solution was applied more frequently. When applying ophthalmic solutions, a balance between washout and dilutional effects should be considered in addition to the therapeutic effect. Investigation of the effect of diquafosol solution (3%) in normal subjects revealed a significant increase in sialic acid concentration, a marker of ocular mucin, at 5 minutes after application, whereas a significant decrease was observed with saline. This result indicates the accelerated secretion of mucin from ocular tissues induced by diquafosol. A clinical study to determine the efficacy of diquafosol in patients with dry eye revealed improvements in tear breakup time, keratoconjunctival staining scores, and Schirmer test score, accompanied by an increase in sialic acid concentration in tears. Investigating normal and dry eye conditions through tear analysis may clarify the pathophysiology of dry eye conditions and support the efficacy of treatments.

  12. Interaction of tearing modes

    International Nuclear Information System (INIS)

    Satya, Y.; Schmidt, G.

    1979-01-01

    A fully developed tearing mode modifies the magnetic field profile. The effect of this profile modification on the linear growth rate of a different tearing mode in a slab and cylindrical geometry is investigated

  13. Land surface and climate parameters and malaria features in Vietnam

    Science.gov (United States)

    Liou, Y. A.; Anh, N. K.

    2017-12-01

    Land surface parameters may affect local microclimate, which in turn alters the development of mosquito habitats and transmission risks (soil-vegetation-atmosphere-vector borne diseases). Forest malaria is a chromic issue in Southeast Asian countries, in particular, such as Vietnam (in 1991, approximate 2 million cases and 4,646 deaths were reported (https://sites.path.org)). Vietnam has lowlands, sub-tropical high humidity, and dense forests, resulting in wide-scale distribution and high biting rate of mosquitos in Vietnam, becoming a challenging and out of control scenario, especially in Vietnamese Central Highland region. It is known that Vietnam's economy mainly relies on agriculture and malaria is commonly associated with poverty. There is a strong demand to investigate the relationship between land surface parameters (land cover, soil moisture, land surface temperature, etc.) and climatic variables (precipitation, humidity, evapotranspiration, etc.) in association with malaria distribution. GIS and remote sensing have been proven their powerful potentials in supporting environmental and health studies. The objective of this study aims to analyze physical attributes of land surface and climate parameters and their links with malaria features. The outcomes are expected to illustrate how remotely sensed data has been utilized in geohealth applications, surveillance, and health risk mapping. In addition, a platform with promising possibilities of allowing disease early-warning systems with citizen participation will be proposed.

  14. Tearing mode instability due to anomalous resistivity

    International Nuclear Information System (INIS)

    Furuya, Atsushi; Itoh, Sanae I.; Yagi, Masatoshi

    2000-01-01

    Tearing mode instability in the presence of microscopic truculence is investigates. The effects of microscopic turbulence on tearing mode are taken as drags which are calculated by one-point renormalization method and mean-field approximation. These effects are reduced to effective diffusivities in reduced MHD equations. Using these equations, the stability analyses of the tearing mode are performed. It is shown that a finite amplitude of fluctuation enhances the growth rate of tearing mode. For very high values of turbulent diffusivities, marginally stable state exists. The effects of each turbulent diffusivity on mode stability are examined near marginal stability boundary. Parameter dependence of the resistive ballooning mode turbulence on tearing mode is analyzed as an example. (author)

  15. Blocked Tear Duct

    Science.gov (United States)

    ... of the nose (lacrimal sac). From there tears travel down a duct (the nasolacrimal duct) draining into your nose. Once in the nose, tears are reabsorbed. A blockage can occur at any point in the tear drainage system, from the puncta ...

  16. Evaporation-driven instability of the precorneal tear film.

    Science.gov (United States)

    Peng, Cheng-Chun; Cerretani, Colin; Braun, Richard J; Radke, C J

    2014-04-01

    Tear-film instability is widely believed to be a signature of eye health. When an interblink is prolonged, randomly distributed ruptures occur in the tear film. "Black spots" and/or "black streaks" appear in 15 to 40 s for normal individuals. For people who suffer from dry eye, tear-film breakup time (BUT) is typically less than a few seconds. To date, however, there is no satisfactory quantitative explanation for the origin of tear rupture. Recently, it was proposed that tear-film breakup is related to locally high evaporative thinning. A spatial variation in the thickness of the tear-film lipid layer (TFLL) may lead to locally elevated evaporation and subsequent tear-film breakup. We examine the local-evaporation-driven tear-film-rupture hypothesis in a one-dimensional (1-D) model for the evolution of a thin aqueous tear film overriding the cornea subject to locally elevated evaporation at its anterior surface and osmotic water influx at its posterior surface. Evaporation rate depends on mass transfer both through the coating lipid layer and through ambient air. We establish that evaporation-driven tear-film breakup can occur under normal conditions but only for higher aqueous evaporation rates. Predicted roles of environmental conditions, such as wind speed and relative humidity, on tear-film stability agree with clinical observations. More importantly, locally elevated evaporation leads to hyperosmolar spots in the tear film and, hence, vulnerability to epithelial irritation. In addition to evaporation rate, tear-film instability depends on the strength of healing flow from the neighboring region outside the breakup region, which is determined by the surface tension at the tear-film surface and by the repulsive thin-film disjoining pressure. This study provides a physically consistent and quantitative explanation for the formation of black streaks and spots in the human tear film during an interblink. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Effect of surface parameter of interband surface mode frequencies of finite diatomic chain

    International Nuclear Information System (INIS)

    Puszkarski, H.

    1982-07-01

    The surface modes of a finite diatomic chain of alternating atoms (M 1 not= M 2 ) are investigated. The surface force constants are assumed to differ from the bulk ones, with the resulting surface parameter a-tilde identical on both ends of the chain. Criteria, governing the existence of interband surface (IBS) modes with frequencies lying in the forbidden gap between acoustical and optical bulk bands for natural (a = 1) as well as non-natural (a not= 1) surface defect, are analysed by the difference equation method. It is found that the IBS modes localize, depending on the value of the surface parameter a, either at the surface of lighter atoms (if a-tilde is positive), or at that of heavier atoms (if a-tilde is negative). Two, one of no IBS modes are found to exist in the chain depending on the relation between the mass ratio and surface parameter - quantities on which the surface localization increment t-tilde depends. If two modes are present (one acoustical and the other optical), their frequencies are disposed symmetrically with respect to the middle of the forbidden gap, provided the surface defect is natural, or asymmetrically - if it is other than natural. If the localization of the IBS mode exceeds a well defined critical value tsub(c), the mode frequency becomes complex, indicating that the mode undergoes a damping. A comparison of the present results and those obtained by Wallis for the diatomic chain with natural surface defect is also given. (author)

  18. Tear exchange and contact lenses: a review.

    Science.gov (United States)

    Muntz, Alex; Subbaraman, Lakshman N; Sorbara, Luigina; Jones, Lyndon

    2015-01-01

    Tear exchange beneath a contact lens facilitates ongoing fluid replenishment between the ocular surface and the lens. This exchange is considerably lower during the wear of soft lenses compared with rigid lenses. As a result, the accumulation of tear film debris and metabolic by-products between the cornea and a soft contact lens increases, potentially leading to complications. Lens design innovations have been proposed, but no substantial improvement in soft lens tear exchange has been reported. Researchers have determined post-lens tear exchange using several methods, notably fluorophotometry. However, due to technological limitations, little remains known about tear hydrodynamics around the lens and, to-date, true tear exchange with contact lenses has not been shown. Further knowledge regarding tear exchange could be vital in aiding better contact lens design, with the prospect of alleviating certain adverse ocular responses. This article reviews the literature to-date on the significance, implications and measurement of tear exchange with contact lenses. Copyright © 2014 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  19. Streaming tearing mode

    Science.gov (United States)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  20. Effect of viscosity on tear drainage and ocular residence time.

    Science.gov (United States)

    Zhu, Heng; Chauhan, Anuj

    2008-08-01

    An increase in residence time of dry eye medications including artificial tears will likely enhance therapeutic benefits. The drainage rates and the residence time of eye drops depend on the viscosity of the instilled fluids. However, a quantitative understanding of the dependence of drainage rates and the residence time on viscosity is lacking. The current study aims to develop a mathematical model for the drainage of Newtonian fluids and also for power-law non-Newtonian fluids of different viscosities. This study is an extension of our previous study on the mathematical model of tear drainage. The tear drainage model is modified to describe the drainage of Newtonian fluids with viscosities higher than the tear viscosity and power-law non-Newtonian fluids with rheological parameters obtained from fitting experimental data in literature. The drainage rate through canaliculi was derived from the modified drainage model and was incorporated into a tear mass balance to calculate the transients of total solute quantity in ocular fluids and the bioavailability of instilled drugs. For Newtonian fluids, increasing the viscosity does not affect the drainage rate unless the viscosity exceeds a critical value of about 4.4 cp. The viscosity has a maximum impact on drainage rate around a value of about 100 cp. The trends are similar for shear thinning power law fluids. The transients of total solute quantity, and the residence time agrees at least qualitatively with experimental studies. A mathematical model has been developed for the drainage of Newtonian fluids and power-law fluids through canaliculi. The model can quantitatively explain different experimental observations on the effect of viscosity on the residence of instilled fluids on the ocular surface. The current study is helpful for understanding the mechanism of fluid drainage from the ocular surface and for improving the design of dry eye treatments.

  1. Tearing mode analysis in tokamaks, revisited

    International Nuclear Information System (INIS)

    Nishimura, Y.; Callen, J.D.; Hegna, C.C.

    1997-12-01

    A new Δ' shooting code has been developed to investigate tokamak plasma tearing mode stability in a cylinder and large aspect ratio (ε ≤ 0.25) toroidal geometries, neglecting toroidal mode coupling. A different computational algorithm is used (shooting out from the singular surface instead of into it) to resolve the strong singularities at the mode rational surface, particularly in the presence of finite pressure term. Numerical results compare favorably with Furth et al. results. The effects of finite pressure, which are shown to decrease Δ', are discussed. It is shown that the distortion of the flux surfaces by the Shafranov shift, which modifies the geometry metric element stabilizes the tearing mode significantly, even in a low β regime before the toroidal magnetic curvature effects come into play. Double tearing modes in toroidal geometries are examined as well. Furthermore, m ≥ 2 tearing mode stability criteria are compared with three dimensional initial value MHD simulation by the FAR code

  2. Impact of initial surface parameters on the final quality of laser micro-polished surfaces

    Science.gov (United States)

    Chow, Michael; Bordatchev, Evgueni V.; Knopf, George K.

    2012-03-01

    Laser micro-polishing (LμP) is a new laser-based microfabrication technology for improving surface quality during a finishing operation and for producing parts and surfaces with near-optical surface quality. The LμP process uses low power laser energy to melt a thin layer of material on the previously machined surface. The polishing effect is achieved as the molten material in the laser-material interaction zone flows from the elevated regions to the local minimum due to surface tension. This flow of molten material then forms a thin ultra-smooth layer on the top surface. The LμP is a complex thermo-dynamic process where the melting, flow and redistribution of molten material is significantly influenced by a variety of process parameters related to the laser, the travel motions and the material. The goal of this study is to analyze the impact of initial surface parameters on the final surface quality. Ball-end micromilling was used for preparing initial surface of samples from H13 tool steel that were polished using a Q-switched Nd:YAG laser. The height and width of micromilled scallops (waviness) were identified as dominant parameter affecting the quality of the LμPed surface. By adjusting process parameters, the Ra value of a surface, having a waviness period of 33 μm and a peak-to-valley value of 5.9 μm, was reduced from 499 nm to 301 nm, improving the final surface quality by 39.7%.

  3. MR imaging of rotator cuff tears

    International Nuclear Information System (INIS)

    Kumagai, Hideo

    1992-01-01

    A total of 115 patients with clinical symptoms and signs suggesting rotator cuff tears underwent MR imaging with a 1.5-Tesla system. The body coil was used as the receiver coil in 24 patients and a single 10 cm surface coil in 91. Arthrography or MR imaging with intra-articular Gd-DTPA (MR arthrography) was performed in 95 of the 115. T2-weighted images with the body coil showed high signal intensity lesions in rotator cuffs in only seven of the 10 patients who had tears demonstrated by arthrography or MR arthrography. On the other hand, T2-weighted images with the surface coil demonstrated high signal intensity lesions in cuffs in all 27 patients who were diagnosed to have tears by arthrography or MR arthrography. In 12 patietns, T2-wighted images with the surface coil showed high signal intensity lesions in cuffs, while arthrography and MR arthrography did not show tears. Surgery was performed in four of the 12 patients and partial tears were confirmed. A single 10 cm surface coil, 3 mm slice thickness and 2.5 second repetition time seem to account for the fine visualization of cuff tears by the T2-weighted images. These results suggest that T2-weighted images obtained with the surface coil are superior to arthrography and MR arthrography. (author)

  4. Ponderomotive modification of drift tearing modes

    International Nuclear Information System (INIS)

    Urquijo, G.; Singh, R.; Sen, A.

    1997-01-01

    The linear characteristics of drift tearing modes are investigated in the presence of a significant background of radio-frequency (RF) waves in the ion cyclotron range of frequencies. The ponderomotive force, arising from the radial gradients in the RF field energy, is found to significantly modify the inner layer solutions of the drift tearing modes. It can have a stabilizing influence, even at moderate RF powers, provided the field energy has a decreasing radial profile at the mode rational surface. (author)

  5. Helical bifurcation and tearing mode in a plasma—a description based on Casimir foliation

    International Nuclear Information System (INIS)

    Yoshida, Z; Dewar, R L

    2012-01-01

    The relation between the helical bifurcation of a Taylor relaxed state (a Beltrami equilibrium) and a tearing mode is analyzed in a Hamiltonian framework. Invoking an Eulerian representation of the Hamiltonian, the symplectic operator (defining a Poisson bracket) becomes non-canonical, i.e. the symplectic operator has a nontrivial cokernel (dual to its nullspace), foliating the phase space into level sets of Casimir invariants. A Taylor relaxed state is an equilibrium point on a Casimir (helicity) leaf. Changing the helicity, equilibrium points may bifurcate to produce helical relaxed states; a necessary and sufficient condition for bifurcation is derived. Tearing yields a helical perturbation on an unstable equilibrium, producing a helical structure approximately similar to a helical relaxed state. A slight discrepancy found between the helically bifurcated relaxed state and the linear tearing mode viewed as a perturbed, singular equilibrium state is attributed to a Casimir element (named ‘helical flux’) pertinent to a ‘resonance singularity’ of the non-canonical symplectic operator. While the helical bifurcation can occur at discrete eigenvalues of the Beltrami parameter, the tearing mode, being a singular eigenfunction, exists for an arbitrary Beltrami parameter. Bifurcated Beltrami equilibria appearing on the same helicity leaf are isolated by the helical-flux Casimir foliation. The obstacle preventing the tearing mode to develop in the ideal limit turns out to be the shielding current sheet on the resonant surface, preventing the release of the ‘potential energy’. When this current is dissipated by resistivity, reconnection is allowed and tearing instability occurs. The Δ′ criterion for linear tearing instability of Beltrami equilibria is shown to be directly related to the spectrum of the curl operator. (paper)

  6. Optimization of vibratory welding process parameters using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pravin Kumar; Kumar, S. Deepak; Patel, D.; Prasad, S. B. [National Institute of Technology Jamshedpur, Jharkhand (India)

    2017-05-15

    The current investigation was carried out to study the effect of vibratory welding technique on mechanical properties of 6 mm thick butt welded mild steel plates. A new concept of vibratory welding technique has been designed and developed which is capable to transfer vibrations, having resonance frequency of 300 Hz, into the molten weld pool before it solidifies during the Shielded metal arc welding (SMAW) process. The important process parameters of vibratory welding technique namely welding current, welding speed and frequency of the vibrations induced in molten weld pool were optimized using Taguchi’s analysis and Response surface methodology (RSM). The effect of process parameters on tensile strength and hardness were evaluated using optimization techniques. Applying RSM, the effect of vibratory welding parameters on tensile strength and hardness were obtained through two separate regression equations. Results showed that, the most influencing factor for the desired tensile strength and hardness is frequency at its resonance value, i.e. 300 Hz. The micro-hardness and microstructures of the vibratory welded joints were studied in detail and compared with those of conventional SMAW joints. Comparatively, uniform and fine grain structure has been found in vibratory welded joints.

  7. Coupling Fluid and Solute Dynamics Within the Ocular Surface Tear Film: A Modelling Study of Black Line Osmolarity

    KAUST Repository

    Zubkov, V. S.; Breward, C. J. W.; Gaffney, E. A.

    2012-01-01

    in these regions. More generally, a heterogeneous distribution of solute concentration is predicted across the ocular surface, indicating that measurements of lower meniscus osmolarity are not globally representative, especially in the presence of dry eye. Vertical

  8. The relationship between tear severity, fatty infiltration, and muscle atrophy in the supraspinatus.

    Science.gov (United States)

    Barry, Jeffrey J; Lansdown, Drew A; Cheung, Sunny; Feeley, Brian T; Ma, C Benjamin

    2013-01-01

    Fatty infiltration and muscle atrophy have been described as interrelated characteristic changes that occur within the muscles of the rotator cuff after cuff tears, and both are independently associated with poor outcomes after surgical repair. We hypothesize that fatty infiltration and muscle atrophy are two distinct processes independently associated with supraspinatus tears. A retrospective review of 377 patients who underwent shoulder magnetic resonance imaging at one institution was performed. Multivariate analysis was performed based on parameters including age, sex, rotator cuff tear severity, fatty infiltration grade, and muscle atrophy. A total of 116 patients (30.8%) had full-thickness tears of the supraspinatus, 153 (40.6%) had partial thickness tears, and 108 (28.7%) had no evidence of tear. With increasing tear severity, the prevalence of substantial fatty infiltration (grade ≥2) increased: 6.5% of patients with no tears vs 41.4% for complete tears (P tear severity: 36.1% of no tears vs 77.6% of complete tears (P muscle atrophy when taking into account sex, age, and tear severity. Fatty infiltration and muscle atrophy are independently associated processes. Fatty infiltration is also related to increasing age, muscle tear severity, and sex, whereas muscle atrophy is related to increasing age but not tear severity. In patients without rotator cuff tears, fatty infiltration and atrophy prevalence increased independently with increasing age. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  9. Posterior horn lateral meniscal tears simulating meniscofemoral ligament attachment in the setting of ACL tear: MRI findings

    International Nuclear Information System (INIS)

    Park, Lawrence S.; Jacobson, Jon A.; Jamadar, David A.; Caoili, Elaine; Kalume-Brigido, Monica; Wojtys, Edward

    2007-01-01

    We have noted apparent far lateral meniscal attachment of the meniscofemoral ligament (MFL) with an anterior cruciate ligament (ACL) tear. This study evaluates MFL attachment and association with posterior horn lateral meniscus (PHLM) tear. Nine months of knee arthroscopy reports were reviewed to classify the PHLM and ACL as torn or normal. After excluding those with prior knee surgery, MR images were reviewed by two radiologists to determine the number of images lateral to PCL, which showed the ligaments of Humphrey and Wrisberg visible as structures separate from the PHLM. Any patient with abnormal PHLM surface signal not continuous with the MFL was excluded. MRI findings were compared with arthroscopy using Student's t test and Fisher's exact test. Of the 54 participants, 5 had PHLM tears and 49 were normal. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. The ligament of Humphrey inserted on average 0.9 consecutive images lateral to the PCL without an PHLM tear and 4.7 with an PHLM tear; the ligament of Wrisberg inserted on average 3.0 consecutive images without an PHLM tear and 4.5 with an PHLM tear (slice thickness/gap = 3 mm/0.5 mm). There was a significant association between PHLM tear and number of images (p = 0.0028), and between ACL tear and this type of PHLM tear (p = 0.0064). Apparent far lateral meniscal extension of a meniscofemoral ligament (greater than or equal to four images lateral to the PCL) should be considered as a possible PHLM tear, especially in the setting of an ACL tear. (orig.)

  10. Magnetic resonance imaging of meniscal bucket-handle tears

    International Nuclear Information System (INIS)

    Dfouni, N.; Garcia, J.; Kindynis, Ph.; Bosson, D.

    1997-01-01

    To define MR signs of meniscal bucket-handle tears and evaluate the diagnostic efficiency of this technique. Retrospective study of 30 patients with a meniscal bucket-handle tear and 30 with a different type of tear, all proven by arthroscopy. The following MR signs of a bucket-handle tear were evaluated: 'separate meniscal fragment, 'double posterior cruciate ligament', 'snake sign' and 'double anterior horn'. A correct diagnosis of a bucket-handle tear was only made in 18/30 of patients. Several of the MR signs were seen in the same patient in 17 cases. A double posterior cruciate ligament was present only in cases of medial meniscus tears. The 12 menisci without these signs, and therefore not diagnosed as bucket-handle tears, were all classified as meniscal tears on the basis of signal extending to the meniscal surface. Nine of these were not displaced into the inter-condylar notch at arthroscopy. The interobserver agreement was excellent: kappa 0.88. The diagnosis of a bucket-handle meniscal tear, if it is displaced, can be made when one or more of the four MR evaluated signs are present. Other forms of meniscal tears are only exceptionally diagnosed as bucket-handle tears. (authors)

  11. Nonlinear dynamics of single-helicity neoclassical MHD tearing instabilities

    International Nuclear Information System (INIS)

    Spong, D.A.; Shaing, K.C.; Carreras, B.A.; Callen, J.D.; Garcia, L.

    1988-10-01

    Neoclassical magnetohydrodynamic (MHD) effects can significantly alter the nonlinear evolution of resistive tearing instabilities. This is studied numerically by using a flux-surface-averaged set of evolution equations that includes the lowest-order neoclassical MHD effects. The new terms in the equations are fluctuating bootstrap current, neoclassical modification of the resistivity, and neoclassical damping of the vorticity. Single-helicity tearing modes are studied in a cylindrical model over a range of neoclassical viscosities (μ/sub e//ν/sup e/) and values of the Δ' parameter of tearing mode theory. Increasing the neoclassical viscosity leads to increased growth rate and saturated island width as predicted analytically. The larger island width is caused by the fluctuating bootstrap current contribution in Ohm's law. The Δ' parameter no longer solely determines the island width, and finite-width saturated islands may be obtained even when Δ' is negative. The importance of the bootstrap current (/approximately/∂/rho///partial derivative/psi/) in the nonlinear dynamics leads us to examine the sensitivity of the results with respect to different models for the density evolution. 11 refs., 8 figs

  12. Convergence of surface diffusion parameters with model crystal size

    Science.gov (United States)

    Cohen, Jennifer M.; Voter, Arthur F.

    1994-07-01

    A study of the variation in the calculated quantities for adatom diffusion with respect to the size of the model crystal is presented. The reported quantities include surface diffusion barrier heights, pre-exponential factors, and dynamical correction factors. Embedded atom method (EAM) potentials were used throughout this effort. Both the layer size and the depth of the crystal were found to influence the values of the Arrhenius factors significantly. In particular, exchange type mechanisms required a significantly larger model than standard hopping mechanisms to determine adatom diffusion barriers of equivalent accuracy. The dynamical events that govern the corrections to transition state theory (TST) did not appear to be as sensitive to crystal depth. Suitable criteria for the convergence of the diffusion parameters with regard to the rate properties are illustrated.

  13. Assessment of lamellar tearing

    International Nuclear Information System (INIS)

    McEnerney, J.W.

    1978-03-01

    Information on lamellar tearing is summarized and related to proposed ASME Code requirements. Lamellar tearing is characterized as a complex phenomenon related to poor short transverse ductility and through-thickness strain. The material, welding, and design variables that affect lamellar tearing are shown to be complex and interrelated. The commonly reported tests for assessing material susceptibility are described, with the controversy over their validity being carefully detailed. Although the use of a nondestructive test such as ultrasonic examination is most desirable, a widely applicable test method does not appear to be available. Of the destructive tests, the short transverse tensile reduction-of-area currently offers the most applicable means of assessing material susceptibility. However, because of the importance of matrix toughness, the short transverse Charpy V-notch test should be considered for use as an additional test if acceptance limits are developed. The ultrasonic detection of lamellar tears is susceptible to interpretation errors, which can make it overly conservative and lead to unnecessary repairs. The repair of tears is described as costly, difficult, and sometimes ineffective. Current design requirements appear to preclude any failures during static and fatigue service loads. However, without improvement of short transverse ductility, certain dynamic service loads could cause lamellar tearing failures. Two alternate design paths are recommended to prevent tearing during fabrication or service loading. The current and proposed ASME requirements dealing with lamellar tearing are reviewed and recommendations are made

  14. Iatrogenic tracheal tear.

    LENUS (Irish Health Repository)

    Dias, A

    2010-10-01

    Large post intubation tracheal tears are usually detected intra-operatively due to unstable signs namely impaired ventilation and mediastinal emphysema and often require surgical management. Smaller tracheal tears are often missed during anaesthesia and recognized during the postoperative period. Conservative management should be considered in these latter cases.

  15. Idiopathic Bilateral Bloody Tearing

    Directory of Open Access Journals (Sweden)

    Emrullah Beyazyıldız

    2015-01-01

    Full Text Available Bloody tear is a rare and distinct clinic phenomenon. We report a case presenting with the complaint of recurrent episodes of bilateral bloody tearing. A 16-year-old girl presented to our clinic with complaint of bloody tearing in both eyes for 3 months. Bloody tearing was not associated with her menses. A blood-stained discharge from the punctum was not observed during the compression of both nasolacrimal ducts. Nasolacrimal passage was not obstructed. Imaging studies such as dacryocystography and gradient-echo magnetic resonance imaging (MRI of nasolacrimal canal were normal. Intranasal endoscopic evaluation was normal. We collected samples from bloody tears two times and pathological examination was performed. Pathological analysis showed lots of squamous cells and no endometrial cells; dysplastic cells were found. Further evaluations for underlying causes were unremarkable. No abnormalities were found in ophthalmologic, radiologic, and pathologic investigations. This condition is likely a rare abnormality and the least recognized aetiology for the idiopathic phenomenon.

  16. Antioxidant content and ultraviolet absorption characteristics of human tears.

    Science.gov (United States)

    Choy, Camus Kar Man; Cho, Pauline; Benzie, Iris F F

    2011-04-01

    Dry eye syndrome is a common age-related disorder, and decreased antioxidant/ultraviolet (UV) radiation protection in tears may be part of the cause. This study aimed to compare the tear antioxidant content and flow rate in young and older adults. The total antioxidant content and UV absorbing properties of various commercially available ophthalmic solutions used to alleviate dry eye symptoms were also examined. Minimally stimulated tears were collected from 120 healthy Chinese adults with no ocular pathology. Two age groups were studied: 19 to 29 years (n = 58) and 50 to 75 years (n = 62). Tear samples from each subject and 13 ophthalmic solutions were analyzed for total antioxidant content (as the Ferric Reducing/Antioxidant Power value). Tear flow rates were estimated from time taken to collect a fixed volume of tear fluid. UV absorbance spectra of pooled fresh reflex tear fluid and the ophthalmic solutions were determined. Results showed that the antioxidant content of minimally stimulated tears from older subjects (398 ± 160 μmol/l) was not significantly lower than that of younger subjects (348 ± 159 μmol/l; p = 0.0915). However, there was a significant difference in the tear flow rates between the two groups (p tears. The effect of low flow rate on the dynamic antioxidant supply to the corneal surface indicates that older subjects have poorer overall defense against photooxidative and other oxidative processes. This could predispose older persons to corneal stress and development of dry eye syndrome. The commercially available artificial tears tested lack both the antioxidant content and UV absorbing characteristics of natural tears. Artificial tears formulations that help restore natural antioxidant and UV absorbing properties to the tear film of the aging eye may help prevent or improve dry eye symptoms and promote ocular health.

  17. Anterior versus posterior, and rim-rent rotator cuff tears: prevalence and MR sensitivity

    International Nuclear Information System (INIS)

    Tuite, M.J.; Turnbull, J.R.; Orwin, J.F.

    1998-01-01

    Purpose. To determine the relative distribution of the locations of rotator cuff tears, and the sensitivity of anterior versus posterior tears on MR images. Patients and methods. We identified 110 consecutive patients who had a shoulder MR and either a partial-thickness or a small full-thickness rotator cuff tear diagnosed at arthroscopy. MR sensitivity and patient age were compared between patients with tears in the anterior and posterior halves of the cuff. In addition, in patients with partial tears less than 2 cm in diameter, an age comparison between those with tears in the critical zone and those with articular surface tears adjacent to the bony insertion (rim-rent tear) was performed. Results. The tear was centered in the anterior half of the rotator cuff in 79% of the patients younger than 36 years old, and in 89% of the patients 36 years old and over. The average age of the patients with tears in the anterior half (44 years) was not significantly different from the average age of those with posterior tears (40 years). The sensitivity of MR for anterior tears was 0.69, and for posterior tears it was 0.56. Five of the nine rim-rent tears (0.56) were interpreted correctly on the original MR report; two of the other tears were misinterpreted as intratendinous fluid but were diagnosable in retrospect. Conclusion. Even in patients less than 36 years old, most partial and small full-thickness rotator cuff tears are centered in the anterior half of the supraspinatus. Although our figure for MR sensitivity for these tears is lower than in recent articles, we found no significant difference between the sensitivity of MR for diagnosing posterior tears versus tears in the anterior half of the supraspinatus tendon. Rim-rent tears can be mistaken for intratendinous signal, and should be carefully looked for in younger patients with shoulder pain. (orig.)

  18. Hemi-bucket-handle tears of the meniscus: appearance on MRI and potential surgical implications

    Energy Technology Data Exchange (ETDEWEB)

    Engstrom, Bjorn I.; Vinson, Emily N.; Helms, Clyde A. [Duke University Medical Center, Department of Radiology, Box 3808, Durham, NC (United States); Taylor, Dean C.; Garrett, William E. [Duke University Medical Center, Department of Orthopaedics, Box 3810, Durham, NC (United States)

    2012-08-15

    To describe a type of meniscus flap tear resembling a bucket-handle tear, named a ''hemi-bucket-handle'' tear; to compare its imaging features with those of a typical bucket-handle tear; and to discuss the potential therapeutic implications of distinguishing these two types of tears. Five knee MR examinations were encountered with a type of meniscus tear consisting of a flap of tissue from the undersurface of the meniscus displaced toward the intercondylar notch. A retrospective analysis of 100 MR examinations prospectively interpreted as having bucket-handle type tears yielded 10 additional cases with this type of tear. Cases of hemi-bucket-handle tears were reviewed for tear location and orientation, appearance of the superior articular surface of the meniscus, presence and location of displaced meniscal tissue, and presence of several classic signs of bucket-handle tears. A total of 15/15 tears involved the medial meniscus, had tissue displaced toward the notch, and were mainly horizontal in orientation. The superior surface was intact in 11/15 (73.3%). In 1/15 (6.7%) there was an absent-bow-tie sign; 6/15 (40%) had a double-PCL sign; 14/15 (93.3%) had a double-anterior horn sign. We describe a type of undersurface flap tear, named a hemi-bucket-handle tear, which resembles a bucket-handle tear. Surgeons at our institution feel this tear would likely not heal if repaired given its predominantly horizontal orientation, and additionally speculate the tear could be overlooked at arthroscopy. Thus, we feel it is important to distinguish this type of tear from the typical bucket-handle tear. (orig.)

  19. Hemi-bucket-handle tears of the meniscus: appearance on MRI and potential surgical implications

    International Nuclear Information System (INIS)

    Engstrom, Bjorn I.; Vinson, Emily N.; Helms, Clyde A.; Taylor, Dean C.; Garrett, William E.

    2012-01-01

    To describe a type of meniscus flap tear resembling a bucket-handle tear, named a ''hemi-bucket-handle'' tear; to compare its imaging features with those of a typical bucket-handle tear; and to discuss the potential therapeutic implications of distinguishing these two types of tears. Five knee MR examinations were encountered with a type of meniscus tear consisting of a flap of tissue from the undersurface of the meniscus displaced toward the intercondylar notch. A retrospective analysis of 100 MR examinations prospectively interpreted as having bucket-handle type tears yielded 10 additional cases with this type of tear. Cases of hemi-bucket-handle tears were reviewed for tear location and orientation, appearance of the superior articular surface of the meniscus, presence and location of displaced meniscal tissue, and presence of several classic signs of bucket-handle tears. A total of 15/15 tears involved the medial meniscus, had tissue displaced toward the notch, and were mainly horizontal in orientation. The superior surface was intact in 11/15 (73.3%). In 1/15 (6.7%) there was an absent-bow-tie sign; 6/15 (40%) had a double-PCL sign; 14/15 (93.3%) had a double-anterior horn sign. We describe a type of undersurface flap tear, named a hemi-bucket-handle tear, which resembles a bucket-handle tear. Surgeons at our institution feel this tear would likely not heal if repaired given its predominantly horizontal orientation, and additionally speculate the tear could be overlooked at arthroscopy. Thus, we feel it is important to distinguish this type of tear from the typical bucket-handle tear. (orig.)

  20. The apparent effect of sample surface damage on the dielectric parameters of GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Engelbrecht, J.A.A. [Physics Department, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa)], E-mail: Japie.Engelbrecht@nmmu.ac.za; Hashe, N.G. [Physics Department, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Hillie, K.T. [CSIR-NML Laboratory, P.O. Box 395, Pretoria 0001 (South Africa); Claassens, C.H. [Physics Department, University of the Free State, Bloemfontein 9300 (South Africa)

    2007-12-15

    The dielectric and optical parameters determined by infrared reflectance spectroscopy and computer simulation of a set of GaAs substrates of various surface topologies are reported. The influence of surface damage on the parameters is noted.

  1. The apparent effect of sample surface damage on the dielectric parameters of GaAs

    International Nuclear Information System (INIS)

    Engelbrecht, J.A.A.; Hashe, N.G.; Hillie, K.T.; Claassens, C.H.

    2007-01-01

    The dielectric and optical parameters determined by infrared reflectance spectroscopy and computer simulation of a set of GaAs substrates of various surface topologies are reported. The influence of surface damage on the parameters is noted

  2. Tear dysfunction and the cornea: LXVIII Edward Jackson Memorial Lecture.

    Science.gov (United States)

    Pflugfelder, Stephen C

    2011-12-01

    To describe the cause and consequence of tear dysfunction-related corneal disease. Perspective on effects of tear dysfunction on the cornea. Evidence is presented on the effects of tear dysfunction on corneal morphology, function, and health, as well as efficacy of therapies for tear dysfunction-related corneal disease. Tear dysfunction is a prevalent eye disease and the most frequent cause for superficial corneal epithelial disease that results in corneal barrier disruption, an irregular optical surface, light scattering, optical aberrations, and exposure and sensitization of pain-sensing nerve endings (nociceptors). Tear dysfunction-related corneal disease causes irritation and visual symptoms such as photophobia and blurred and fluctuating vision that may decrease quality of life. Dysfunction of 1 or more components of the lacrimal functional unit results in changes in tear composition, including elevated osmolarity and increased concentrations of matrix metalloproteinases, inflammatory cytokines, and chemokines. These tear compositional changes promote disruption of tight junctions, alter differentiation, and accelerate death of corneal epithelial cells. Corneal epithelial disease resulting from tear dysfunction causes eye irritation and decreases visual function. Clinical and basic research has improved understanding of the pathogenesis of tear dysfunction-related corneal epithelial disease, as well as treatment outcomes. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Evaluating tear clearance rate with optical coherence tomography.

    Science.gov (United States)

    Garaszczuk, Izabela K; Mousavi, Maryam; Cervino Exposito, Alejandro; Bartuzel, Maciej M; Montes-Micó, Robert; Iskander, D Robert

    2018-02-01

    To assess the early-phase of tear clearance rate (TCR) with anterior segment optical coherence tomography (OCT) and to determine the association between TCR and other clinical measures of the tear film in a group of young subjects with different levels of tear film quality. TCR was classified as the percentage decrease of subject's inferior tear meniscus height 30s after instillation of 5μl 0.9% saline solution. Fifty subjects (32F and 18M) aged (mean±standard deviation) 25.5±4.3 years volunteered for the study. It consisted of a review of medical history, Ocular Surface Disease Index (OSDI) questionnaire, tear film osmolarity measurements, slit lamp examination and TCR estimation based on dynamic measurements of the lower tear meniscus with OCT. Estimates of TCR were contrasted against subject age and tear film measures commonly used for dry eye diagnosis, which includes OSDI score, fluorescein tear film break-up time (FBUT), tear meniscus height (TMH), blinking frequency, tear film osmolarity and corneal staining. The group mean TCR was 29±13% and 36±19% respectively after 30 and 60s margin after saline solution instillation. Statistically significant correlations were found between TCR and FBUT (r 2 =0.319, placrimal functional unit. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  4. Diet, nutraceuticals and the tear film.

    Science.gov (United States)

    Jalbert, Isabelle

    2013-12-01

    Nutrition disorders and their correlates such as obesity are increasingly prevalent worldwide. A number of studies to date have suggested numerous potential associations between diet and tear film health; this paper will provide a summary of the available literature. The tear film is characterized through its protein and lipid content and through clinical measurements of characteristics such as osmolarity, volume and stability. Malnutrition, protein and vitamin-A deficiencies are extremely deleterious to tear film health and supplementation with oral vitamin A in this setting is of clear benefit. The relative impact of diet on tear film within what would be considered normal ranges of consumption is less clear. A number of population studies have suggested that hyperlipidemia and a diet low in omega-3 fatty acids are risks factor for dry eye disease. Numerous studies have investigated the effectiveness of oral supplementation with antioxidants, omega-3 (e.g. fish oil and linseed oil) and omega-6 (e.g. evening primrose oil) fatty acids in the last 10 years. Taken together, these suggest a small benefit of oral supplementation on tear film volume, stability and decreased ocular symptoms in patients previously diagnosed with diseases involving the ocular surface (e.g. Sjögren's syndrome, meibomian gland dysfunction, dry eye disease) and contact lens wearers suffering from dry eye. More research is required to determine the exact composition, dosage and indications for their use and to fully characterize how these nutraceuticals modulate the tear film. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Human tears reveal insights into corneal neovascularization.

    Science.gov (United States)

    Zakaria, Nadia; Van Grasdorff, Sigi; Wouters, Kristien; Rozema, Jos; Koppen, Carina; Lion, Eva; Cools, Nathalie; Berneman, Zwi; Tassignon, Marie-José

    2012-01-01

    Corneal neovascularization results from the encroachment of blood vessels from the surrounding conjunctiva onto the normally avascular cornea. The aim of this study is to identify factors in human tears that are involved in development and/or maintenance of corneal neovascularization in humans. This could allow development of diagnostic tools for monitoring corneal neovascularization and combination monoclonal antibody therapies for its treatment. In an observational case-control study we enrolled a total of 12 patients with corneal neovascularization and 10 healthy volunteers. Basal tears along with reflex tears from the inferior fornix, superior fornix and using a corneal bath were collected along with blood serum samples. From all patients, ocular surface photographs were taken. Concentrations of the pro-angiogenic cytokines interleukin (IL)-6, IL-8, Vascular Endothelial Growth Factor (VEGF), Monocyte Chemoattractant Protein 1 (MCP-1) and Fas Ligand (FasL) were determined in blood and tear samples using a flow cytometric multiplex assay. Our results show that the concentration of pro-angiogenic cytokines in human tears are significantly higher compared to their concentrations in serum, with highest levels found in basal tears. Interestingly, we could detect a significantly higher concentration of IL- 6, IL-8 and VEGF in localized corneal tears of patients with neovascularized corneas when compared to the control group. This is the first study of its kind demonstrating a significant difference of defined factors in tears from patients with neovascularized corneas as compared to healthy controls. These results provide the basis for future research using animal models to further substantiate the role of these cytokines in the establishment and maintenance of corneal neovascularization.

  6. The effect of selected parameters of the honing process on cylinder liner surface topography

    International Nuclear Information System (INIS)

    Pawlus, P; Dzierwa, A; Michalski, J; Reizer, R; Wieczorowski, M; Majchrowski, R

    2014-01-01

    Many truck cylinder liners made from gray cast iron were machined. Ceramic and diamond honing stones were used in the last stages of operation: coarse honing and plateau honing. The effect of honing parameters on the cylinder liner surface topography was studied. Selected surface topography parameters were response variables. It was found that parameters from the Sq group were sensitive to honing parameter change. When plateau honing time varied, the Smq parameter increased, while the other parameters, Spq and Svq, were stable. (papers)

  7. Effects of tear film dynamics on quality of vision.

    Science.gov (United States)

    Koh, Shizuka; Tung, Cynthia I; Inoue, Yasushi; Jhanji, Vishal

    2018-06-15

    The precorneal tear film is maintained by blinking and exhibits different phases in the tear cycle. The tear film serves as the most anterior surface of the eye and plays an important role as a first refractive component of the eye. Alterations in tear film dynamics may cause both vision-related and ocular surface-related symptoms. Although the optical quality associated with the tear film dynamics previously received little attention, objective measurements of optical quality using wavefront sensors have enabled us to quantify optical aberrations induced by the tear film. This has provided an objective method for assessing reduced optical quality in dry eye; thus, visual disturbances were included in the definition of dry eye disease in the 2007 Dry Eye Workshop report. In addition, sequential measurements of wavefront aberrations have provided us with valuable insights into the dynamic optical changes associated with tear film dynamics. This review will focus on the current knowledge of the mechanisms of wavefront variations that are caused by different aspects of tear film dynamics: specifically, quality, quantity and properties of the tear film, demonstrating the respective effects of dry eye, epiphora and instillation of eye drops on the quality of vision. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  8. As tears go by : Baby tears trigger more brain activity than adult tears in nulliparous women

    NARCIS (Netherlands)

    Hendricx-Riem, M.M.E.; De Carli, P.; van IJzendoorn, M.H.; Vingerhoets, A.J.J.M.; Bakermans-Kranenburg, M.J.

    2017-01-01

    The current functional magnetic resonance imaging study examines brain activity during the perception of infant and adult tears. Infant tears evoke stronger responses in the visual cortex than adult tears, indicating that infant tears are highly salient. In addition, our study shows that infant

  9. Hip Labral Tear

    Science.gov (United States)

    ... that joint in the future. Prevention Hip labral tears are often associated with sports participation. If your sport puts a lot of strain on your hips, condition the surrounding muscles with strength and flexibility exercises. Try to avoid ...

  10. Haemolacria (bloody tears)

    African Journals Online (AJOL)

    PROF. EZECHUKWU

    2014-08-06

    Aug 6, 2014 ... menstruation, drugs, hyperthyroidism, nasolacrimal tu- berculosis ... no bleeding from any other body orifice. However ... All age groups can be affected from infancy to ... the system and thus lead to bloody tears emerging from.

  11. Meniscotibial (coronary) ligament tears

    International Nuclear Information System (INIS)

    El-Khoury, G.Y.; Usta, H.Y.; Berger, R.A.

    1984-01-01

    Preservation of the meniscus whenever possible is essential in maintaining knee stability and preventing premature osteoarthritis. Peripheral meniscal tears are the most amenable to surgical repair. This study evaluates the peripheral attachments of the medial meniscus and focuses on a specific tear limited to the meniscotibial ligament (coronary ligament). The diagnosis is made arthrographically when the medial meniscus floats above the tibial plateau without separating completely from the capsule. The lateral meniscus is rarely involved in this type of injury. (orig.)

  12. The Effect of Polar Lipids on Tear Film Dynamics

    KAUST Repository

    Aydemir, E.; Breward, C. J. W.; Witelski, T. P.

    2010-01-01

    In this paper, we present a mathematical model describing the effect of polar lipids, excreted by glands in the eyelid and present on the surface of the tear film, on the evolution of a pre-corneal tear film. We aim to explain the interesting

  13. Multi-Parameter Analysis of Surface Finish in Electro-Discharge Machining of Tool Steels

    Directory of Open Access Journals (Sweden)

    Cornelia Victoria Anghel

    2006-10-01

    Full Text Available The paper presents a multi- parameter analysis of surface finish imparted to tool-steel plates by electro-discharge machining (EDM is presented. The interrelationship between surface texture parameters and process parameters is emphasized. An increased number of parameters is studied including amplitude, spacing, hybrid and fractal parameters,, as well. The correlation of these parameters with the machining conditions is investigated. Observed characteristics become more pronounced, when intensifying machining conditions. Close correlation exists between certain surface finish parameters and EDM input variables and single and multiple statistical regression models are developed.

  14. Accuracy of MR imaging in partial tears of rotator cuff

    International Nuclear Information System (INIS)

    Eto, Masao; Ito, Nobuyuki; Tomonaga, Tadashi; Harada, Shin'ichi; Rabbi, M.E.; Iwasaki, Katsuro

    1997-01-01

    MRI is very useful for the diagnosis of the rotator cuff tear However. in case of partial tears it is sometimes controvertible. In this study, we studied the accuracy of MRI in the diagnosis of partial tears. 67 patients who underwent MRI investigation before operation were chosen for this study. There were 61 males and 6 females, ranging from 30 to 80 years (mean: 54.8 years at the time of operation). MRI was performed with 1.5T superconductive system with shoulder surface coil. MPGR T2-weighted images were performed in the coronal oblique and sagittal oblique planes. Complete tears were diagnosed when full thickness high intensity was observed in the rotator cuff, whereas with partial high intensity of the rotator cuff, was considered as partial tears. MRI demonstrated 77.8% sensitivity, 91.4% specificity and 89.6% accuracy in the diagnosis of partial tear. In 8 cases MRI had misinterpretation. In MPGR T2-weighted images, not only the partial tears but the degenerative changes also show high intensity of the rotator cuff. Therefore, it is difficult to differentiate and maybe this is the reason of misinterpretations of partial tears by MRI. MRI provided with useful pre-operative informations of partial tears of the rotator cuff. However, in few cases it is hard to differentiate for the degenerative changes of the rotator cuff. (author)

  15. How to Select the most Relevant Roughness Parameters of a Surface: Methodology Research Strategy

    Science.gov (United States)

    Bobrovskij, I. N.

    2018-01-01

    In this paper, the foundations for new methodology creation which provides solving problem of surfaces structure new standards parameters huge amount conflicted with necessary actual floors quantity of surfaces structure parameters which is related to measurement complexity decreasing are considered. At the moment, there is no single assessment of the importance of a parameters. The approval of presented methodology for aerospace cluster components surfaces allows to create necessary foundation, to develop scientific estimation of surfaces texture parameters, to obtain material for investigators of chosen technological procedure. The methods necessary for further work, the creation of a fundamental reserve and development as a scientific direction for assessing the significance of microgeometry parameters are selected.

  16. Human tears contain a chemosignal.

    Science.gov (United States)

    Gelstein, Shani; Yeshurun, Yaara; Rozenkrantz, Liron; Shushan, Sagit; Frumin, Idan; Roth, Yehudah; Sobel, Noam

    2011-01-14

    Emotional tearing is a poorly understood behavior that is considered uniquely human. In mice, tears serve as a chemosignal. We therefore hypothesized that human tears may similarly serve a chemosignaling function. We found that merely sniffing negative-emotion-related odorless tears obtained from women donors induced reductions in sexual appeal attributed by men to pictures of women's faces. Moreover, after sniffing such tears, men experienced reduced self-rated sexual arousal, reduced physiological measures of arousal, and reduced levels of testosterone. Finally, functional magnetic resonance imaging revealed that sniffing women's tears selectively reduced activity in brain substrates of sexual arousal in men.

  17. a Research on Monitoring Surface Deformation and Relationships with Surface Parameters in Qinghai Tibetan Plateau Permafrost

    Science.gov (United States)

    Mi, S. J.; Li, Y. T.; Wang, F.; Li, L.; Ge, Y.; Luo, L.; Zhang, C. L.; Chen, J. B.

    2017-09-01

    The Qinghai Tibetan Plateau permafrost has been the largest permafrost region in middle-low latitude in the world for its high altitude. For the large area permafrost, especially surface deformation brought by it, have serious influence on the road engineering, road maintaining and regional economic development. Consequently, it is essential to monitor the surface deformation and study factors that influent it. We monitored an area named Wudaoliang from July 25, 2015 to June 1, 2016 and 15 Sentinel images were obtained during this time. The area we chose is about 35 kilometers long and 2 kilometers wide, and the national road 109 of China passes through the area. The traditional PS-INSAR (Persistent Scatterer Interferometric Synthetic Aperture Radar) method is not suitable because less historical images in the research area and leading to the number of PS (Persistent Scatterer) points is not enough to obtain accurate deformation results. Therefore, in this paper, we used another method which named QUASI-PSInSAR (QUASI Persistent Scatterer Interferometric Synthetic Aperture Radar) to acquire deformation for it has the advantage to weaken or eliminate the effects of spatial and temporal correlation, which has proved by other scholar. After processing 15 images in the SARproz software, we got the conclusions that, 1) the biggest deformation velocity in the whole area was about 127.9mm/year and about 109.3 mm/year in the road; 2) apparent deformation which have surface deformation more than 30mm/year was about 1.7Km in the road. Meanwhile, soil moisture(SM), Land surface temperature (LST) and surface water(SW), which are primary parameters of the land surface over the same time were reversed by using Sentinel data, Landsat data and ZY-3 data, respectively. After analyzing SM, LST , SW and deformation, we obtained that wet areas which had bigger SM, lower LST and more SW, had greater percentage of severe deformation than arid areas; besides, deformation pattern were

  18. Allergy and allergic mediators in tears.

    Science.gov (United States)

    Leonardi, Andrea

    2013-12-01

    The identification of inflammatory mediators in the tear fluid have been extensively used in ocular allergy to find either a 'disease marker', to better understand the immune mechanisms involved in the ocular surface inflammation, or to identify potential targets for therapeutic interventions. While the clinical characteristics allow a relatively convincing diagnosis of ocular allergic diseases, in the initial, non active phases, or in the chronic stages, the diagnosis may not be clear. Although not highly specific, total tear IgE can be measured with local tests by inserting a paper strip in the lower meniscus. The measurement of tear specific inflammatory markers, such as histamine, tryptase, ECP, IL-4, IL-5 and eotaxin, may be useful for the diagnosis or monitoring ocular allergy. New technologies such as multiplex bead assays, membrane-bound antibody array and proteomic techniques can characterize the distribution of a wide range of bioactive trace proteins in tears. Dozens of mediators, cytokines, chemokines, growth factors, angiogenic modulators, enzymes and inhibitors were thus identified in small tear samples using these techniques, providing the possible identification of specific biomarker for either specific disease or disease activity. However, to date, there is no a single specific laboratory test suitable for the diagnosis and monitoring of allergic conjunctivitis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Tear secretion and tear stability of women on hormonal contraceptives

    Directory of Open Access Journals (Sweden)

    Faustina Kemdinum Idu

    2013-01-01

    Conclusions: Injectable hormonal contraceptives had no significant effects on tear secretion and tear stability of healthy women of childbearing age. Further studies may be required to determine the effects of hormonal contraceptives on tear volume and stability of women with dry eyes.

  20. Influence of additive laser manufacturing parameters on surface using density of partially melted particles

    Science.gov (United States)

    Rosa, Benoit; Brient, Antoine; Samper, Serge; Hascoët, Jean-Yves

    2016-12-01

    Mastering the additive laser manufacturing surface is a real challenge and would allow functional surfaces to be obtained without finishing. Direct Metal Deposition (DMD) surfaces are composed by directional and chaotic textures that are directly linked to the process principles. The aim of this work is to obtain surface topographies by mastering the operating process parameters. Based on experimental investigation, the influence of operating parameters on the surface finish has been modeled. Topography parameters and multi-scale analysis have been used in order to characterize the DMD obtained surfaces. This study also proposes a methodology to characterize DMD chaotic texture through topography filtering and 3D image treatment. In parallel, a new parameter is proposed: density of particles (D p). Finally, this study proposes a regression modeling between process parameters and density of particles parameter.

  1. Nonlinear drift tearing mode

    International Nuclear Information System (INIS)

    Zelenyj, L.M.; Kuznetsova, M.M.

    1989-01-01

    Nonlinear study of magnetic perturbation development under single-mode conditions in collision-free plasma in configurations with the magnetic field shear is investigated. Results are obtained with regard of transverse component of electrical field and its effect on ion dynamics within wide range of ion Larmor radius value and values of magnetic field shear. Increments of nonlinear drift tearing mode are obtained and it is shown that excitation drastic conditions of even linearly stable modes are possible. Mechanism of instability nonlinear stabilization is considered and the value of magnetic island at the saturation threshold is estimeted. Energy of nonlinear drift tearing mode is discussed

  2. Evaluation of ground stiffness parameters using continuous surface wave geophysics

    DEFF Research Database (Denmark)

    Gordon, Anne; Foged, Niels

    2000-01-01

    Present day knowledge of the magnitude of the strain levels in the ground associated with geotechnical structures, together with an increasing number of projects requiring the best estimates of ground movements around excavations, has led to, inter alia, increased interest in measuring the very......-small-strain stiffness of the ground Gmax. Continuous surface wave geophysics offers a quick, non-intrusive and economical way of making such measurements. This paper reviews the continuous surface wave techniques and evaluates, in engineering terms, the applicability of the method to the site investigation industry....

  3. Effect of machining parameters on surface finish of Inconel 718 in end milling

    Directory of Open Access Journals (Sweden)

    Sarkar Bapi

    2017-01-01

    Full Text Available Surface finish is an important criteria in machining process and selection of proper machining parameters is important to obtain good surface finish. In the present work effects of the machining parameters in end milling of Inconel 718 were investigated. Central composite design was used to design the total number of experiments. A Mathematical model for surface roughness has been developed using response surface methodology. In this study, the influence of cutting parameters such as cutting speed, feed rate and depth of cut on surface roughness was analyzed. The study includes individual effect of cutting parameters on surface roughness as well as their interaction. The analysis of variance (ANOVA was employed to find the validity of the developed model. The results show that depth of cut mostly affected the surface roughness. It is also observed that surface roughness values are comparable in both dry and wet machining conditions.

  4. Influence of growth parameters on the surface morphology and ...

    Indian Academy of Sciences (India)

    Unknown

    surface features of the grown film like terracing, inclusions, meniscus lines, etc are ... Recently, studies carried out on the growth of InSb ..... is a critical factor in any epitaxial growth process and can ... However, this approach can lead to.

  5. Effects of XPS operational parameters on investigated sample surfaces

    International Nuclear Information System (INIS)

    Mrad, O.; Ismail, I.

    2013-04-01

    In this work, we studied the effects of the operating conditions of the xray photoelectron spectroscopy analysis technique (XPS) on the investigated samples. Firstly, the performances of the whole system have been verified as well as the accuracy of the analysis. Afterwards, the problem of the analysis of insulating samples caused by the charge buildup on the surface has been studied. The use of low-energy electron beam (<100 eV) to compensate the surface charge has been applied. The effect of X-ray on the samples have been assessed and was found to be nondestructive within the analysis time. The effect of low- and high-energy electron beams on the sample surface have been investigated. Highenergy electrons were found to have destructive effect on organic samples. The sample heating procedure has been tested and its effect on the chemical stat of the surface was followed. Finally, the ion source was used to determine the elements distribution and the chemical stat of different depths of the sample. A method has been proposed to determine these depths (author).

  6. DETERMINATION OF OPTIMAL BALL BURNISHING PARAMETERS FOR SURFACE ROUGHNESS OF ALUMINUM ALLOY

    Directory of Open Access Journals (Sweden)

    D.B. Patel

    2013-06-01

    Full Text Available Burnishing is a cold-working process, which easily produces a smooth and work-hardened surface through the plastic deformation of surface irregularities. In the present work, the influences of the main burnishing parameters (speed, feed, force, number of tool passes, and ball diameter on the surface roughness are studied. It is found that the burnishing forces and the number of tool passes are the parameters that have the greatest effect on the workpiece surface during the burnishing process.

  7. Non-linear evolution of double tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Fredrickson, E.; Bell, M.; Budny, R.V.; Synakowski, E.

    1999-01-01

    The delta prime formalism with neoclassical modifications has proven to be a useful tool in the study of tearing modes in high beta, collisionless plasmas. In this paper the formalism developed for the inclusion of neoclassical effects on tearing modes in monotonic q-profile plasmas is extended to plasmas with hollow current profiles and double rational surfaces. First, the classical formalism of tearing modes in the Rutherford regime in low beta plasmas is extended to q profiles with two rational surfaces. Then it is shown that this formalism is readily extended to include neoclassical effects

  8. A mass and solute balance model for tear volume and osmolarity in the normal and the dry eye

    KAUST Repository

    Gaffney, E.A.; Tiffany, J.M.; Yokoi, N.; Bron, A.J.

    2010-01-01

    Tear hyperosmolarity is thought to play a key role in the mechanism of dry eye, a common symptomatic condition accompanied by visual disturbance, tear film instability, inflammation and damage to the ocular surface. We have constructed a model

  9. Bayesian estimation of regularization parameters for deformable surface models

    International Nuclear Information System (INIS)

    Cunningham, G.S.; Lehovich, A.; Hanson, K.M.

    1999-01-01

    In this article the authors build on their past attempts to reconstruct a 3D, time-varying bolus of radiotracer from first-pass data obtained by the dynamic SPECT imager, FASTSPECT, built by the University of Arizona. The object imaged is a CardioWest total artificial heart. The bolus is entirely contained in one ventricle and its associated inlet and outlet tubes. The model for the radiotracer distribution at a given time is a closed surface parameterized by 482 vertices that are connected to make 960 triangles, with nonuniform intensity variations of radiotracer allowed inside the surface on a voxel-to-voxel basis. The total curvature of the surface is minimized through the use of a weighted prior in the Bayesian framework, as is the weighted norm of the gradient of the voxellated grid. MAP estimates for the vertices, interior intensity voxels and background count level are produced. The strength of the priors, or hyperparameters, are determined by maximizing the probability of the data given the hyperparameters, called the evidence. The evidence is calculated by first assuming that the posterior is approximately normal in the values of the vertices and voxels, and then by evaluating the integral of the multi-dimensional normal distribution. This integral (which requires evaluating the determinant of a covariance matrix) is computed by applying a recent algorithm from Bai et. al. that calculates the needed determinant efficiently. They demonstrate that the radiotracer is highly inhomogeneous in early time frames, as suspected in earlier reconstruction attempts that assumed a uniform intensity of radiotracer within the closed surface, and that the optimal choice of hyperparameters is substantially different for different time frames

  10. Effect of electro-co-deposition parameters on surface mechanical ...

    Indian Academy of Sciences (India)

    Particle size distribution of procured TiO2 powder. ... substrate were obtained by using Philips X'Pert System. ... by a drop. In case of Cu–TiO2 composite coating also similar trend in RTC of (220) was ... of hydrogen evolution at the cathode surface due to over voltage. At 30 g l−1 TiO2 with 5 A dm−2 current density the.

  11. Rotator cuff tears in children and adolescents: experience at a large pediatric hospital

    International Nuclear Information System (INIS)

    Zbojniewicz, Andrew M.; Emery, Kathleen H.; Maeder, Matthew E.; Salisbury, Shelia R.

    2014-01-01

    Prior literature, limited to small case series and case reports, suggests that rotator cuff tears are rare in adolescents. However, we have identified rotator cuff tears in numerous children and adolescents who have undergone shoulder MRI evaluation. The purpose of this study is to describe the prevalence and characteristics of rotator cuff tears in children and adolescents referred for MRI evaluation of the shoulder at a large pediatric hospital and to correlate the presence of rotator cuff tears with concurrent labral pathology, skeletal maturity and patient activity and outcomes. We reviewed reports from 455 consecutive non-contrast MRI and magnetic resonance arthrogram examinations of the shoulder performed during a 2-year period, and following exclusions we yielded 205 examinations in 201 patients (ages 8-18 years; 75 girls, 126 boys). Rotator cuff tears were classified by tendon involved, tear thickness (partial or full), surface and location of tear (when partial) and presence of delamination. We recorded concurrent labral pathology when present. Physeal patency of the proximal humerus was considered open, closing or closed. Statistical analysis was performed to evaluate for a relationship between rotator cuff tears and degree of physeal patency. We obtained patient activity at the time of injury, surgical reports and outcomes from clinical records when available. Twenty-five (12.2%) rotator cuff tears were identified in 17 boys and 7 girls (ages 10-18 years; one patient had bilateral tears). The supraspinatus tendon was most frequently involved (56%). There were 2 full-thickness and 23 partial-thickness tears with articular-side partial-thickness tears most frequent (78%). Insertional partial-thickness tears were more common (78%) than critical zone tears (22%) and 10 (43%) partial-thickness tears were delamination tears. Nine (36%) patients with rotator cuff tears had concurrent labral pathology. There was no statistically significant relationship between

  12. Rotator cuff tears in children and adolescents: experience at a large pediatric hospital

    Energy Technology Data Exchange (ETDEWEB)

    Zbojniewicz, Andrew M.; Emery, Kathleen H. [University of Cincinnati College of Medicine, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States); Maeder, Matthew E. [University of Cincinnati College of Medicine, Department of Radiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States); Lenox Hill Hospital, Department of Radiology, New York, NY (United States); Salisbury, Shelia R. [University of Cincinnati College of Medicine, Division of Biostatistics and Epidemiology, Cincinnati Children' s Hospital Medical Center, Cincinnati, OH (United States)

    2014-06-15

    Prior literature, limited to small case series and case reports, suggests that rotator cuff tears are rare in adolescents. However, we have identified rotator cuff tears in numerous children and adolescents who have undergone shoulder MRI evaluation. The purpose of this study is to describe the prevalence and characteristics of rotator cuff tears in children and adolescents referred for MRI evaluation of the shoulder at a large pediatric hospital and to correlate the presence of rotator cuff tears with concurrent labral pathology, skeletal maturity and patient activity and outcomes. We reviewed reports from 455 consecutive non-contrast MRI and magnetic resonance arthrogram examinations of the shoulder performed during a 2-year period, and following exclusions we yielded 205 examinations in 201 patients (ages 8-18 years; 75 girls, 126 boys). Rotator cuff tears were classified by tendon involved, tear thickness (partial or full), surface and location of tear (when partial) and presence of delamination. We recorded concurrent labral pathology when present. Physeal patency of the proximal humerus was considered open, closing or closed. Statistical analysis was performed to evaluate for a relationship between rotator cuff tears and degree of physeal patency. We obtained patient activity at the time of injury, surgical reports and outcomes from clinical records when available. Twenty-five (12.2%) rotator cuff tears were identified in 17 boys and 7 girls (ages 10-18 years; one patient had bilateral tears). The supraspinatus tendon was most frequently involved (56%). There were 2 full-thickness and 23 partial-thickness tears with articular-side partial-thickness tears most frequent (78%). Insertional partial-thickness tears were more common (78%) than critical zone tears (22%) and 10 (43%) partial-thickness tears were delamination tears. Nine (36%) patients with rotator cuff tears had concurrent labral pathology. There was no statistically significant relationship between

  13. Anterior versus posterior, and rim-rent rotator cuff tears: prevalence and MR sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Tuite, M J; Turnbull, J R; Orwin, J F [Wisconsin Univ., Madison, WI (United States). Dept. of Radiology

    1998-05-01

    Purpose. To determine the relative distribution of the locations of rotator cuff tears, and the sensitivity of anterior versus posterior tears on MR images. Patients and methods. We identified 110 consecutive patients who had a shoulder MR and either a partial-thickness or a small full-thickness rotator cuff tear diagnosed at arthroscopy. From the arthroscopy videotapes, we classified the tears as centered in the anterior or posterior half of the cuff, and as either in the critical zone or adjacent to the bony insertion. The original MR interpretation was compared with the arthroscopic findings. MR sensitivity and patient age were compared between patients with tears in the anterior and posterior halves of the cuff. In addition, in patients with partial tears less than 2 cm in diameter, an age comparison between those with tears in the critical zone and those with articular surface tears adjacent to the bony insertion (rim-rent tear) was performed. Results. The tear was centered in the anterior half of the rotator cuff in 79% of the patients younger than 36 years old, and in 89% of the patients 36 years old and over. The average age of the patients with tears in the anterior half (44 years) was not significantly different from the average age of those with posterior tears (40 years)(P=0.23). The sensitivity of MR for anterior tears was 0.69, and for posterior tears it was 0.56 (P=0.17). The average age of the 9 patients with rim-rent tears was 31 years, while that of the 28 patients with similarly-sized partial tears not involving the insertion was 40 years old (P=0.048). Five of the nine rim-rent tears (0.56) were interpreted correctly on the original MR report; two of the other tears were misinterpreted as intratendinous fluid but were diagnosable in retrospect. Conclusion. Even in patients less than 36 years old, most partial and small full-thickness rotator cuff tears are centered in the anterior half of the supraspinatus. Although our figure for MR sensitivity

  14. An unscaled parameter to measure the order of surfaces: a new surface elaboration to increase cells adhesion.

    Science.gov (United States)

    Bigerelle, M; Anselme, K; Dufresne, E; Hardouin, P; Iost, A

    2002-08-01

    We present a new parameter to quantify the order of a surface. This parameter is scale-independent and can be used to compare the organization of a surface at different scales of range and amplitude. To test the accuracy of this roughness parameter versus a hundred existing ones, we created an original statistical bootstrap method. In order to assess the physical relevance of this new parameter, we elaborated a great number of surfaces with various roughness amplitudes on titanium and titanium-based alloys using different physical processes. Then we studied the influence of the roughness amplitude on in vitro adhesion and proliferation of human osteoblasts. It was then shown that our new parameter best discriminates among the cell adhesion phenomena than others' parameters (Average roughness (Ra em leader )): cells adhere better on isotropic surfaces with a low order, provided this order is quantified on a scale that is more important than that of the cells. Additionally, on these low ordered metallic surfaces, the shape of the cells presents the same morphological aspect as that we can see on the human bone trabeculae. The method used to prepare these isotropic surfaces (electroerosion) could be undoubtedly and easily applied to prepare most biomaterials with complex geometries and to improve bone implant integration. Moreover, the new order parameter we developed may be particularly useful for the fundamental understanding of the mechanism of bone cell installation on a relief and of the formation of bone cell-material interface.

  15. Design parameters for measurements of local catalytic activity on surfaces

    DEFF Research Database (Denmark)

    Johansson, Martin; Johannessen, Tue; Jørgensen, Jan Hoffmann

    2006-01-01

    Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward......, the limits of the range in reaction rate, which can be Studied are estimated. (c) 2005 Elsevier B.V. All rights reserved.......Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward...... limit for the lateral resolution of the measurement, and that a flow rate of the order of 240 (ml/min)(n) is sufficient to achieve this resolution. The sensitivity is reasonable also with high flow rates, due to the presence of a pocket of stagnant gas under the tip of the capillary. Furthermore...

  16. Experimental and Numerical Investigation of Design Parameters for Hydronic Embedded Thermally Active Surfaces

    DEFF Research Database (Denmark)

    Marcos-Meson, Victor; Pomianowski, Michal Zbigniew; E. Poulsen, Søren

    2015-01-01

    This paper evaluates the principal design parameters affecting the thermal performance of embedded hydronic Thermally Active Surfaces (TAS), combining the Response Surface Method (RSM) with the Finite Elements Method (FEM). The study ranks the combined effects of the parameters on the heat flux i...

  17. On the spectra and coherence of some surface meteorological parameters in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    RameshKumar, M.R.; Fernandes, A.A.

    . In addition to peaks in the annual, semiannual and four-month periodicities, the various surface parameters exhibited some energy at 2, 3 and 4 year cycles. It was also found that most of the surface meteorological parameters were coherent (at 95% confidence...

  18. Software Simulation of Hot Tearing

    DEFF Research Database (Denmark)

    Andersen, S.; Hansen, P.N.; Hattel, Jesper Henri

    1999-01-01

    The brittleness of a solidifying alloy in a temperature range near the solidus temperature has been recognised since the fifties as the mechanism responsible for hot tearing. Due to this brittlenes, the metal will crack under even small amounts of strain in that temperature range. We see these hot...... tears in castings close to hot centres, where the level of strain is often too high.Although the hot tearing mechanism is well understood, until now it has been difficult to do much to reduce the hot tearing tendency in a casting. In the seventies, good hot tearing criteria were developed by considering...... the solidification rate and the strain rate of the hot tear prone areas. But, until recently it was only possible to simulate the solidification rate, so that the criteria could not be used effectively.Today, with new software developments, it is possible to also simulate the strain rate in the hot tear prone areas...

  19. MODELING AND OPTIMIZATION OF CYLINDRICAL GRINDING PARAMETERS FOR MRR AND SURFACE ROUGHNESS

    OpenAIRE

    Kshitij R Patil1, Rupesh J Karande2, Dadaso D. Mohite3, Vishwas S Jadhav4

    2017-01-01

    Cylindrical grinding is one of the important metal cutting processes used extensively in the finishing operations. The grinding process plays an important role in every manufacturing activity. The surface properties can be altered by changing various grinding parameters in order to achieve best surface finish resulting in low surface roughness value and with possible maximum metal removal rate. Four parameters, namely spindle speed, feed rate, depth of cut and hardness of material were identi...

  20. Deriving global parameter estimates for the Noah land surface model using FLUXNET and machine learning

    Science.gov (United States)

    Chaney, Nathaniel W.; Herman, Jonathan D.; Ek, Michael B.; Wood, Eric F.

    2016-11-01

    With their origins in numerical weather prediction and climate modeling, land surface models aim to accurately partition the surface energy balance. An overlooked challenge in these schemes is the role of model parameter uncertainty, particularly at unmonitored sites. This study provides global parameter estimates for the Noah land surface model using 85 eddy covariance sites in the global FLUXNET network. The at-site parameters are first calibrated using a Latin Hypercube-based ensemble of the most sensitive parameters, determined by the Sobol method, to be the minimum stomatal resistance (rs,min), the Zilitinkevich empirical constant (Czil), and the bare soil evaporation exponent (fxexp). Calibration leads to an increase in the mean Kling-Gupta Efficiency performance metric from 0.54 to 0.71. These calibrated parameter sets are then related to local environmental characteristics using the Extra-Trees machine learning algorithm. The fitted Extra-Trees model is used to map the optimal parameter sets over the globe at a 5 km spatial resolution. The leave-one-out cross validation of the mapped parameters using the Noah land surface model suggests that there is the potential to skillfully relate calibrated model parameter sets to local environmental characteristics. The results demonstrate the potential to use FLUXNET to tune the parameterizations of surface fluxes in land surface models and to provide improved parameter estimates over the globe.

  1. Global High Resolution Sea Surface Flux Parameters From Multiple Satellites

    Science.gov (United States)

    Zhang, H.; Reynolds, R. W.; Shi, L.; Bates, J. J.

    2007-05-01

    Advances in understanding the coupled air-sea system and modeling of the ocean and atmosphere demand increasingly higher resolution data, such as air-sea fluxes of up to 3 hourly and every 50 km. These observational requirements can only be met by utilizing multiple satellite observations. Generation of such high resolution products from multiple-satellite and in-situ observations on an operational basis has been started at the U.S. National Oceanic and Atmospheric Administration (NOAA) National Climatic Data Center. Here we describe a few products that are directly related to the computation of turbulent air-sea fluxes. Sea surface wind speed has been observed from in-situ instruments and multiple satellites, with long-term observations ranging from one satellite in the mid 1987 to six or more satellites since mid 2002. A blended product with a global 0.25° grid and four snapshots per day has been produced for July 1987 to present, using a near Gaussian 3-D (x, y, t) interpolation to minimize aliases. Wind direction has been observed from fewer satellites, thus for the blended high resolution vector winds and wind stresses, the directions are taken from the NCEP Re-analysis 2 (operationally run near real time) for climate consistency. The widely used Reynolds Optimum Interpolation SST analysis has been improved with higher resolutions (daily and 0.25°). The improvements use both infrared and microwave satellite data that are bias-corrected by in- situ observations for the period 1985 to present. The new versions provide very significant improvements in terms of resolving ocean features such as the meandering of the Gulf Stream, the Aghulas Current, the equatorial jets and other fronts. The Ta and Qa retrievals are based on measurements from the AMSU sounder onboard the NOAA satellites. Ta retrieval uses AMSU-A data, while Qa retrieval uses both AMSU-A and AMSU-B observations. The retrieval algorithms are developed using the neural network approach. Training

  2. [Rotator cuff tear athropathy prevalence].

    Science.gov (United States)

    Guerra-Soriano, F; Encalada-Díaz, M I; Ruiz-Suárez, M; Valero-González, F S

    2017-01-01

    Glenohumeral arthritis secondary to massive rotator cuff tear presents with a superior displacement and femoralization of the humeral head with coracoacromial arch acetabularization. The purpose of this study was to establish prevalence of rotator cuff tear artropathy (CTA) at our institution. Four hundred electronic records were reviewed from which we identified 136 patients with rotator cuff tears. A second group was composed with patients with massive cuff tears that were analized and staged by the Seebauer cuff tear arthropathy classification. Thirty four patients with massive rotator cuff tears were identified, 8 male and 26 female (age 60.1 ± 10.26 years). Massive rotator cuff tear prevalence was 25%. CTA prevalence found in the rotator cuff group was 19 and 76% in the massive cuff tears group. Patients were staged according to the classification with 32% in stage 1a, 11% 1b, 32% 2a and 0% 2b. CTA prevalence in patients with rotator cuff tears and massive cuff tears is higher than the one reported in American population. We consider that a revision of the Seebauer classification to be appropriate to determine its reliability.

  3. Ultrasonography versus magnetic resonance imaging in detecting and grading common extensor tendon tear in chronic lateral epicondylitis.

    Directory of Open Access Journals (Sweden)

    Artur Bachta

    Full Text Available To investigate the diagnostic performance and reliability of ultrasonography (US in detecting and grading common extensor tendon (CET tear in patients with chronic lateral epicondylitis (LE, using magnetic resonance imaging (MRI as the reference standard.The study comprised fifty-eight chronic LE patients. Each patient underwent US and MRI. CET status was classified as: high-grade tear (≥50% thickness, low-grade tear (<50% thickness, suspected tear (possible but not evident tear, no tear. Additionally, the following dichotomous scale was used: confirmed or unconfirmed CET tear. Relative US parameters (versus MRI for detecting CET tear included: sensitivity, specificity, positive predictive value (PPV, negative predictive value (NPV and accuracy. The agreement between US and MRI findings was measured using the weighted Cohen kappa coefficient (κ.US showed moderate agreement with MRI in detecting and grading CET tear (κ = 0.49. Sensitivity, specificity, and accuracy in CET tear detecting by US were 64.52%, 85.19%, and 72.73%, respectively. PPV and NPV of US were 83.33% and 67.65%, respectively. No patient with unconfirmed CET tear on US had high-grade CET tear on MRI.Ultrasonography is a valuable imaging modality that can be used as a screening tool to exclude high-grade CET tear in chronic LE patients. Once a tear is evident on US, MRI should be considered to assess precisely the extent of tendon injury.

  4. Cemental tear: To know what we have neglected in dental practice

    Directory of Open Access Journals (Sweden)

    Po-Yuan Jeng

    2018-04-01

    Full Text Available Cemental tear is a special kind of root surface fracture, contributing to periodontal and periapical breakdown. However, it is a challenge for doctors to diagnose, resulting in delayed or improper treatment. We reviewed the predisposing factors, location, radiographic/clinical characteristics, diagnosis and treatments of cemental tears. From the literature, patients with cemental tear were mainly males, over 60 year-old. Possible predisposing factors include gender, age, tooth type, traumatic occlusal force and vital teeth. Cemental tears were common in upper and lower anterior teeth, single or multiple, and can be present in cervical, middle and apical third of roots. Morphology of cemental tears can be either piece-shaped or U-shaped. Clinically, cemental tear shows a unitary periodontal pocket and signs/symptoms mimicking localized periodontitis, apical periodontitis and vertical root fractures. Treatment of cemental tears include scaling, root planning, root canal treatment, periodontal/periapical surgery, guided tissue regeneration, bone grafting, and intentional replantation. Recurrence of cemental tear is possible especially when the fracture involves root apex. Extraction is recommended for teeth with poor prognosis. In conclusion, cemental tears can involve both periodontal and periapical area. Dentists should understand the predisposing factors and clinical features of cemental tears for early diagnosis/treatment to prevent bone loss/tooth extraction. Keywords: Cemental tear, Clinical characteristics, Surface root fracture, Periodontal/periapical breakdown, Recurrence, Predisposing factors

  5. Stability of tearing modes in tokamak plasmas

    International Nuclear Information System (INIS)

    Hegna, C.C.; Callen, J.D.

    1994-02-01

    The stability properties of m ≥ 2 tearing instabilities in tokamak plasmas are analyzed. A boundary layer theory is used to find asymptotic solutions to the ideal external kink equation which are used to obtain a simple analytic expression for the tearing instability parameter Δ'. This calculation generalizes previous work on this topic by considering more general toroidal equilibria (however, toroidal coupling effects are ignored). Constructions of Δ' are obtained for plasmas with finite beta and for islands that have nonzero width. A simple heuristic estimate is given for the value of the saturated island width when the instability criterion is violated. A connection is made between the calculation of the asymptotic matching parameter in the finite beta and island width case to the nonlinear analog of the Glasser effect

  6. Effect of laser cutting parameters on surface roughness of stainless steel 307

    Directory of Open Access Journals (Sweden)

    Amal NASSAR

    2016-12-01

    Full Text Available Optimal parameters of laser cutting are an important step to improve surface quality of cutting edge in the laser cutting of stainless steel 307. This paper presents a new approach for optimizing the cutting parameters on stainless steel. Based on 33 full factorial experimental design, cutting experiments were conducted for stainless steel 307 plates using a laser machine (AMADA FONT 3015. The cutting parameters such as, cutting speed, cutting power and gas pressure are optimized for maximizing surface quality. The results indicated that cutting power and cutting speed play an important role in surface quality.

  7. MR imaging of delamination tears of the rotator cuff tendons

    International Nuclear Information System (INIS)

    Walz, Daniel M.; Chen, Steven; Miller, Theodore T.; Hofman, Josh

    2007-01-01

    The objective was to describe the imaging appearances and location of delamination tears of the rotator cuff tendons on non-contrast conventional MR imaging. This study was reviewed and approved by our Institutional Review Board. The reports of 548 consecutive MR examinations of the shoulder were reviewed, looking for mention or description of delamination tears of the rotator cuff. The images of the identified cases were then reviewed by two radiologists to confirm the findings. Correlation with surgical and arthroscopic information was then performed. Delamination tears were defined as horizontal retraction of either the bursal or articular surface of the tendon, manifest as thickening of the torn retracted edge, and/or interstitial splitting of the tendon, manifest as fluid-like high signal intensity on fat-suppressed T2-weighted oblique coronal images. Fourteen cases of delamination tears were identified in 13 patients. Ten of the cases involved the supraspinatus tendon, all with articular surface involvement. Nine of these supraspinatus cases were isolated tears and one occurred as part of a full thickness tear. All 10 of these supraspinatus cases showed medial retraction of the articular surface of the tendon, with thickening of the retracted edge, and 5 of the 10 had a demonstrable horizontal cleft in the interstitium. Four cases involved the subscapularis tendon, with articular surface disruption in three and pure interstitial delamination in one. Medial subluxation of the tendon of the long head of the biceps was present in all four cases. No delamination tears occurred on the bursal surface. Only three of the 14 shoulders underwent surgical repair with one confirmation of supraspinatus delamination, one confirmation of a subscapularis tear that had become a full thickness tear 10 months after initial imaging and another interstitial subscapularis delamination that was not identified arthroscopically. Delamination tears occur most often in the

  8. MR imaging of delamination tears of the rotator cuff tendons

    Energy Technology Data Exchange (ETDEWEB)

    Walz, Daniel M.; Chen, Steven [North Shore University Hospital, Department of Radiology, Manhasset, NY (United States); Miller, Theodore T. [Hospital for Special Surgery, Department of Radiology and Imaging, New York, NY (United States); Hofman, Josh [Long Island Jewish Medical Center, New Hyde Park, NY (United States)

    2007-05-15

    The objective was to describe the imaging appearances and location of delamination tears of the rotator cuff tendons on non-contrast conventional MR imaging. This study was reviewed and approved by our Institutional Review Board. The reports of 548 consecutive MR examinations of the shoulder were reviewed, looking for mention or description of delamination tears of the rotator cuff. The images of the identified cases were then reviewed by two radiologists to confirm the findings. Correlation with surgical and arthroscopic information was then performed. Delamination tears were defined as horizontal retraction of either the bursal or articular surface of the tendon, manifest as thickening of the torn retracted edge, and/or interstitial splitting of the tendon, manifest as fluid-like high signal intensity on fat-suppressed T2-weighted oblique coronal images. Fourteen cases of delamination tears were identified in 13 patients. Ten of the cases involved the supraspinatus tendon, all with articular surface involvement. Nine of these supraspinatus cases were isolated tears and one occurred as part of a full thickness tear. All 10 of these supraspinatus cases showed medial retraction of the articular surface of the tendon, with thickening of the retracted edge, and 5 of the 10 had a demonstrable horizontal cleft in the interstitium. Four cases involved the subscapularis tendon, with articular surface disruption in three and pure interstitial delamination in one. Medial subluxation of the tendon of the long head of the biceps was present in all four cases. No delamination tears occurred on the bursal surface. Only three of the 14 shoulders underwent surgical repair with one confirmation of supraspinatus delamination, one confirmation of a subscapularis tear that had become a full thickness tear 10 months after initial imaging and another interstitial subscapularis delamination that was not identified arthroscopically. Delamination tears occur most often in the

  9. Analysis of Cytokine Levels in Tears and Clinical Correlations After Intense Pulsed Light Treating Meibomian Gland Dysfunction.

    Science.gov (United States)

    Liu, Ruixing; Rong, Bei; Tu, Ping; Tang, Yun; Song, Wenjing; Toyos, Rolando; Toyos, Melissa; Yan, Xiaoming

    2017-11-01

    To investigate the change from baseline of inflammatory markers in tears of dry eye disease (DED) subjects owing to meibomian gland dysfunction (MGD) after intense pulsed light (IPL) treatment and meibomian gland expression (MGE) compared to sham treatment, and the correlations with ocular surface parameters. Randomized, double-masked, controlled study. Those randomized into the active treatment arm received 3 consecutive treatments (14∼16 J/cm 2 ) approximately 4 weeks apart in the periocular region. Control eyes received 3 treatments in the same intervals of 0 J/cm 2 . Tear samples in all eyes were collected and analyzed at baseline, week 12, and/or week 4 for interleukin (IL)-17A, IL-6, and prostaglandin E2 (PGE2). The correlations between cytokines and ocular surface parameters were analyzed before and after IPL treatment. All of the inflammatory markers declined in value compared to baselines. IL-17A and IL-6 showed statistically significant decreases compared to sham treatment at each measured time point. PGE2 showed statistically significant decreases compared to sham at week 12. Results showed that the expressions of IL-17A and IL-6 correlated well with ocular surface parameters of the lower eyelid before IPL. The changed values of IL-6 and PGE2 in tears correlated with the changed values of partial ocular surface parameters after IPL treatment in study eyes, respectively. The study results suggest that IPL can significantly reduce inflammatory markers in tears of patients suffering with DED owing to MGD after IPL treatment. These findings indicate that IL-17A and IL-6 play roles in the pathogenesis of DED owing to MGD, and the reduction of the inflammatory factors is consistent with the improvement of partial clinical symptoms and signs. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  10. Improving weather predictability by including land-surface model parameter uncertainty

    Science.gov (United States)

    Orth, Rene; Dutra, Emanuel; Pappenberger, Florian

    2016-04-01

    The land surface forms an important component of Earth system models and interacts nonlinearly with other parts such as ocean and atmosphere. To capture the complex and heterogenous hydrology of the land surface, land surface models include a large number of parameters impacting the coupling to other components of the Earth system model. Focusing on ECMWF's land-surface model HTESSEL we present in this study a comprehensive parameter sensitivity evaluation using multiple observational datasets in Europe. We select 6 poorly constrained effective parameters (surface runoff effective depth, skin conductivity, minimum stomatal resistance, maximum interception, soil moisture stress function shape, total soil depth) and explore their sensitivity to model outputs such as soil moisture, evapotranspiration and runoff using uncoupled simulations and coupled seasonal forecasts. Additionally we investigate the possibility to construct ensembles from the multiple land surface parameters. In the uncoupled runs we find that minimum stomatal resistance and total soil depth have the most influence on model performance. Forecast skill scores are moreover sensitive to the same parameters as HTESSEL performance in the uncoupled analysis. We demonstrate the robustness of our findings by comparing multiple best performing parameter sets and multiple randomly chosen parameter sets. We find better temperature and precipitation forecast skill with the best-performing parameter perturbations demonstrating representativeness of model performance across uncoupled (and hence less computationally demanding) and coupled settings. Finally, we construct ensemble forecasts from ensemble members derived with different best-performing parameterizations of HTESSEL. This incorporation of parameter uncertainty in the ensemble generation yields an increase in forecast skill, even beyond the skill of the default system. Orth, R., E. Dutra, and F. Pappenberger, 2016: Improving weather predictability by

  11. Numerical Δ' studies of the nonlinear finite-β tearing mode

    International Nuclear Information System (INIS)

    Pletzer, A.

    1996-01-01

    Tearing modes have recently attracted attention following theoretical successes in predicting the presence of magnetic island with moderate poloidal m = 3,4 and toroidal n = 2,3 mode numbers during TFTR (Tokamak Fusion Test Reactor) supershots. Classical linear resistive mode theory predicts instability when the asymptotic matching index Δ' defined as the jump of logarithmic derivative of the radial magnetic perturbation across the rational surface is positive. Recently, it was suggested that tearing modes could also persist when Δ'<0 provided bootstrap current effects are taken into account. In all the above theories, the crucial parameter which determines the stability from both the geometry and equilibrium profiles is Δ'. It is shown in the present study that the Δ' of the (m=2, n=1) mode computed with the PEST-3 code is virtually always positive. Saturation can nevertheless be achieved provided the symmetry breaking term of a current gradient is included in the resistive layer. (author) 3 figs., 11 refs

  12. Proteomic analysis of tears following acupuncture treatment for menopausal dry eye disease by two-dimensional nano-liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Liu, Qingyu; Liu, Junling; Ren, Chengda; Cai, Wenting; Wei, Qingquan; Song, Yi; Yu, Jing

    2017-01-01

    The purpose of this study was to investigate whether acupuncture is effective at treating dry eye disease among postmenopausal women and to identify the possible mechanisms. Twenty-eight postmenopausal women with dry eye disease were randomly divided into two groups: an acupuncture plus artificial tears (AC + AT) group and an artificial tears (AT) only group. After baseline examination of clinical parameters and tear sample collection, each patient received the designated modality of topical therapy for 2 months. Post-treatment documentation of clinical parameters was recorded, and tear samples were collected. Tear samples from the AC + AT group were subjected to two-dimensional nano-liquid chromatography coupled with tandem mass spectrometry (2D nano-LC-MS/MS). Western blot analysis was also performed on tear samples from both groups. After treatment, the Ocular Surface Disease Index scores, symptom assessment scores, scores of sign assessment, and tear break-up time were significantly improved in both groups ( P =0.000). Symptom assessment scores were significantly improved in the AC + AT group ( P =0.000) compared with the AT group. 2D nano-LC-MS/MS identified 2,411 proteins, among which 142 were downregulated and 169 were upregulated. After combined AC + AT treatment, the abundance of secreted proteins was increased, whereas that of cytoplasmic proteins decreased (Pearson's χ 2 test, P =0.000, P =0.000, respectively). Proteins involved in immunity and regulation were also more abundant (Pearson's χ 2 test, P =0.040, P =0.016, respectively), while components and proliferation-related proteins were downregulated (Pearson's χ 2 test, P =0.003, P =0.011, respectively). AC + AT treatment increased protein synthesis and secretion, and improved clinical symptoms. These results indicate that acupuncture may be a complimentary therapy for treating postmenopausal dry eye disease.

  13. Posterior horn medial meniscal root tear: the prequel

    Energy Technology Data Exchange (ETDEWEB)

    Umans, H. [Albert Einstein College of Medicine, Bronx, NY (United States); Lenox Hill Radiology and Imaging Associates, New York, NY (United States); Morrison, W. [Thomas Jefferson University Hospital, Philadelphia, PA (United States); DiFelice, G.S. [Hospital for Special Surgery, New York, NY (United States); Vaidya, N. [Crystal Run Healthcare, Middletown, NY (United States); Winalski, C.S. [Cleveland Clinic, Imaging Institute, Department of Biomedical Engineering, Lerner Research Institute, Cleveland, OH (United States)

    2014-06-15

    meniscal body results in increased stress on the medial weight-bearing surfaces often leading to articular cartilage loss; we observed this sequence in six of our 15 patients with PHMMR tears. (orig.)

  14. Calculation of parameter failure probability of thermodynamic system by response surface and importance sampling method

    International Nuclear Information System (INIS)

    Shang Yanlong; Cai Qi; Chen Lisheng; Zhang Yangwei

    2012-01-01

    In this paper, the combined method of response surface and importance sampling was applied for calculation of parameter failure probability of the thermodynamic system. The mathematics model was present for the parameter failure of physics process in the thermodynamic system, by which the combination arithmetic model of response surface and importance sampling was established, then the performance degradation model of the components and the simulation process of parameter failure in the physics process of thermodynamic system were also present. The parameter failure probability of the purification water system in nuclear reactor was obtained by the combination method. The results show that the combination method is an effective method for the calculation of the parameter failure probability of the thermodynamic system with high dimensionality and non-linear characteristics, because of the satisfactory precision with less computing time than the direct sampling method and the drawbacks of response surface method. (authors)

  15. EFFECT OF PLASMA CUTTING PARAMETERS UPON SHAPES OF BEARING CURVE OF C45 STEEL SURFACE

    Directory of Open Access Journals (Sweden)

    Agnieszka Skoczylas

    2015-08-01

    Full Text Available The article presents the results of studies on the effect of plasma cutting technological parameters upon the shape of bearing curves and the parameters of the curve. The topography of surface formed by plasma cutting were analyzed. For measuring surface roughness and determining the bearing curve the appliance T8000 RC120 – 400 by Hommel-Etamic was used together with software.

  16. Analyzing parameters optimisation in minimising warpage on side arm using response surface methodology (RSM)

    Science.gov (United States)

    Rayhana, N.; Fathullah, M.; Shayfull, Z.; Nasir, S. M.; Hazwan, M. H. M.

    2017-09-01

    This paper presents a systematic methodology to analyse the warpage of the side arm part using Autodesk Moldflow Insight software. Response Surface Methodology (RSM) was proposed to optimise the processing parameters that will result in optimal solutions by efficiently minimising the warpage of the side arm part. The variable parameters considered in this study was based on most significant parameters affecting warpage stated by previous researchers, that is melt temperature, mould temperature and packing pressure while adding packing time and cooling time as these is the commonly used parameters by researchers. The results show that warpage was improved by 10.15% and the most significant parameters affecting warpage are packing pressure.

  17. Influence of Wire Electrical Discharge Machining (WEDM) process parameters on surface roughness

    Science.gov (United States)

    Yeakub Ali, Mohammad; Banu, Asfana; Abu Bakar, Mazilah

    2018-01-01

    In obtaining the best quality of engineering components, the quality of machined parts surface plays an important role. It improves the fatigue strength, wear resistance, and corrosion of workpiece. This paper investigates the effects of wire electrical discharge machining (WEDM) process parameters on surface roughness of stainless steel using distilled water as dielectric fluid and brass wire as tool electrode. The parameters selected are voltage open, wire speed, wire tension, voltage gap, and off time. Empirical model was developed for the estimation of surface roughness. The analysis revealed that off time has a major influence on surface roughness. The optimum machining parameters for minimum surface roughness were found to be at a 10 V open voltage, 2.84 μs off time, 12 m/min wire speed, 6.3 N wire tension, and 54.91 V voltage gap.

  18. Analysis of WEDM Process Parameters on Surface Roughness and Kerf using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Asfana Banu

    2017-12-01

    Full Text Available In obtaining the best quality of engineering parts, the quality of machined surface plays an essential role. The fatigue strength, wear resistance, and corrosion of workpiece are some of the aspects of the qualities that can be improved. This paper investigates the effect of wire electrical discharge machining (WEDM process parameters on surface roughness and kerf on stainless steel using distilled water as dielectric fluid and brass wire as tool electrode. The selected process parameters are voltage open, wire speed, wire tension, voltage gap, and off time. Empirical models using Taguchi method were developed for the estimation of surface roughness and kerf. The analysis revealed that off time has major influence on surface roughness and kerf. The optimum machining parameters for minimum surface roughness and kerf were found to be 10 V open voltage, 2.84 µs off time, 12 m/min wire speed, 6.3 N wire tension, and 54.91 V voltage gap.

  19. Effect of laser parameters on surface roughness of laser modified tool steel after thermal cyclic loading

    Science.gov (United States)

    Lau Sheng, Annie; Ismail, Izwan; Nur Aqida, Syarifah

    2018-03-01

    This study presents the effects of laser parameters on the surface roughness of laser modified tool steel after thermal cyclic loading. Pulse mode Nd:YAG laser was used to perform the laser surface modification process on AISI H13 tool steel samples. Samples were then treated with thermal cyclic loading experiments which involved alternate immersion in molten aluminium (800°C) and water (27°C) for 553 cycles. A full factorial design of experiment (DOE) was developed to perform the investigation. Factors for the DOE are the laser parameter namely overlap rate (η), pulse repetition frequency (f PRF) and peak power (Ppeak ) while the response is the surface roughness after thermal cyclic loading. Results indicate the surface roughness of the laser modified surface after thermal cyclic loading is significantly affected by laser parameter settings.

  20. Estimation of the solubility parameters of model plant surfaces and agrochemicals: a valuable tool for understanding plant surface interactions.

    Science.gov (United States)

    Khayet, Mohamed; Fernández, Victoria

    2012-11-14

    Most aerial plant parts are covered with a hydrophobic lipid-rich cuticle, which is the interface between the plant organs and the surrounding environment. Plant surfaces may have a high degree of hydrophobicity because of the combined effects of surface chemistry and roughness. The physical and chemical complexity of the plant cuticle limits the development of models that explain its internal structure and interactions with surface-applied agrochemicals. In this article we introduce a thermodynamic method for estimating the solubilities of model plant surface constituents and relating them to the effects of agrochemicals. Following the van Krevelen and Hoftyzer method, we calculated the solubility parameters of three model plant species and eight compounds that differ in hydrophobicity and polarity. In addition, intact tissues were examined by scanning electron microscopy and the surface free energy, polarity, solubility parameter and work of adhesion of each were calculated from contact angle measurements of three liquids with different polarities. By comparing the affinities between plant surface constituents and agrochemicals derived from (a) theoretical calculations and (b) contact angle measurements we were able to distinguish the physical effect of surface roughness from the effect of the chemical nature of the epicuticular waxes. A solubility parameter model for plant surfaces is proposed on the basis of an increasing gradient from the cuticular surface towards the underlying cell wall. The procedure enabled us to predict the interactions among agrochemicals, plant surfaces, and cuticular and cell wall components, and promises to be a useful tool for improving our understanding of biological surface interactions.

  1. Enamel surface topography analysis for diet discrimination. A methodology to enhance and select discriminative parameters

    Science.gov (United States)

    Francisco, Arthur; Blondel, Cécile; Brunetière, Noël; Ramdarshan, Anusha; Merceron, Gildas

    2018-03-01

    Tooth wear and, more specifically, dental microwear texture is a dietary proxy that has been used for years in vertebrate paleoecology and ecology. DMTA, dental microwear texture analysis, relies on a few parameters related to the surface complexity, anisotropy and heterogeneity of the enamel facets at the micrometric scale. Working with few but physically meaningful parameters helps in comparing published results and in defining levels for classification purposes. Other dental microwear approaches are based on ISO parameters and coupled with statistical tests to find the more relevant ones. The present study roughly utilizes most of the aforementioned parameters in their more or less modified form. But more than parameters, we here propose a new approach: instead of a single parameter characterizing the whole surface, we sample the surface and thus generate 9 derived parameters in order to broaden the parameter set. The identification of the most discriminative parameters is performed with an automated procedure which is an extended and refined version of the workflows encountered in some studies. The procedure in its initial form includes the most common tools, like the ANOVA and the correlation analysis, along with the required mathematical tests. The discrimination results show that a simplified form of the procedure is able to more efficiently identify the desired number of discriminative parameters. Also highlighted are some trends like the relevance of working with both height and spatial parameters, as well as the potential benefits of dimensionless surfaces. On a set of 45 surfaces issued from 45 specimens of three modern ruminants with differences in feeding preferences (grazing, leaf-browsing and fruit-eating), it is clearly shown that the level of wear discrimination is improved with the new methodology compared to the other ones.

  2. An evaluation of Retaine™ ophthalmic emulsion in the management of tear film stability and ocular surface staining in patients diagnosed with dry eye

    Directory of Open Access Journals (Sweden)

    Ousler III G

    2015-02-01

    Full Text Available George Ousler III,1 Douglas K Devries,2 Paul M Karpecki,3 Joseph B Ciolino41Ora, Inc, Andover, MA, USA; 2Eye Care Associates of Nevada, Sparks, NV, USA; 3Koffler Vision Group, Lexington, KY, USA; 4Massachusetts Eye and Ear, Boston, MA, USAAbstract: A single-center, open-label study consisting of two visits over the course of approximately 2 weeks was conducted to evaluate the efficacy of Retaine™ ophthalmic emulsion in improving the signs and symptoms of dry eye. Forty-two subjects were enrolled and received 1–2 drops twice daily of Retaine™ beginning at the first visit (day 1 and ending at the second visit. Subjects were instructed to complete a symptomatology diary twice daily prior to drop instillation through the morning of the second visit. Ocular sign and symptom assessments, visual acuity procedures, and comfort assessments were conducted during both visits. A statistically significant reduction was observed in mean breakup area on the second visit between the predose time and the postdose time (P=0.026. On the second visit, subjects had significantly less corneal fluorescein staining in the superior (P=0.002, central (P=0.017, corneal sum (P=0.011, and all ocular regions combined (P=0.038 than on the first visit. On the second visit, statistically significant reductions in dryness (P<0.001, grittiness (P=0.0217, ocular discomfort (P=0.0017, and all symptoms (P<0.001 were also seen as measured by the Ora Calibra™ Ocular Discomfort and 4-Symptom Questionnaire (0–5 scale. Subjects reported a statistically significant improvement in their abilities to work with a computer at night (P=0.044. Mean drop comfort scores ranged from 1.29–1.81 on the Ora Calibra™ 0–10 Drop Comfort Scale, on which 0 is very comfortable and 10 is very uncomfortable. Retaine™ demonstrates promising results as a novel artificial tear option for individuals suffering from dry eye. The unique mechanism of action of Retaine™ provides enhanced comfort

  3. The influence of the surface parameter changes onto the phonon states in ultrathin crystalline films

    Science.gov (United States)

    Šetrajčić, Jovan P.; Ilić, Dušan I.; Jaćimovski, Stevo K.

    2018-04-01

    In this paper, we have analytically investigated how the changes in boundary surface parameters influence the phonon dispersion law in ultrathin films of the simple cubic crystalline structure. Spectra of possible phonon states are analyzed using the method of two-time dependent Green's functions and for the diverse combination of boundary surface parameters, this problem was presented numerically and graphically. It turns out that for certain values and combinations of parameters, displacement of dispersion branches outside of bulk zone occurs, leading to the creation of localized phonon states. This fact is of great importance for the heat removal, electrical conductivity and superconducting properties of ultrathin films.

  4. Wind direction dependent vertical wind shear and surface roughness parameter in two different coastal environments

    International Nuclear Information System (INIS)

    Bagavathsingh, A.; Srinivas, C.V.; Baskaran, R.; Venkatraman, B.; Sardar Maran, P.

    2016-01-01

    Atmospheric boundary layer parameters and surface layer parameterizations are important prerequisites for air pollution dispersion analysis. The turbulent flow characteristics vary at coastal and inland sites where the nuclear facilities are situated. Many pollution sources and their dispersion occur within the roughness sub layer in the lower atmosphere. In this study analysis of wind direction dependence vertical wind shear, surface roughness lengths and surface layer wind condition has been carried out at a coastal and the urban coastal site for the different wind flow regime. The differential response of the near coastal and inland urban site SBL parameters (wind shear, roughness length, etc) was examined as a function of wind direction

  5. Functional parameter screening for predicting durability of rolling sliding contacts with different surface finishes

    Science.gov (United States)

    Dimkovski, Z.; Lööf, P.-J.; Rosén, B.-G.; Nilsson, P. H.

    2018-06-01

    The reliability and lifetime of machine elements such as gears and rolling bearings depend on their wear and fatigue resistance. In order to screen the wear and surface damage, three finishing processes: (i) brushing, (ii) manganese phosphating and (iii) shot peening were applied on three disc pairs and long-term tested on a twin-disc tribometer. In this paper, the elastic contact of the disc surfaces (measured after only few revolutions) was simulated and a number of functional and roughness parameters were correlated. The functional parameters consisted of subsurface stresses at different depths and a new parameter called ‘pressure spikes’ factor’. The new parameter is derived from the pressure distribution and takes into account the proximity and magnitude of the pressure spikes. Strong correlations were found among the pressure spikes’ factor and surface peak/height parameters. The orthogonal shear stresses and Von Mises stresses at the shallowest depths under the surface have shown the highest correlations but no good correlations were found when the statistics of the whole stress fields was analyzed. The use of the new parameter offers a fast way to screen the durability of the contacting surfaces operating at similar conditions.

  6. Investigation of ellipsometric parameters of 2D microrough surfaces by FDTD.

    Science.gov (United States)

    Qiu, J; Ran, D F; Liu, Y B; Liu, L H

    2016-07-10

    Ellipsometry is a powerful method for measuring the optical constants of materials and is very sensitive to surface roughness. In previous ellipsometric measurement of optical constants of solid materials with rough surfaces, researchers frequently used effective medium approximation (EMA) with roughness already known to fit the complex refractive index of the material. However, the ignored correlation length, the other important parameter of rough surfaces, will definitely result in fitting errors. Hence it is necessary to consider the influence of surface roughness and correlation length on the ellipsometric parameters Δ (phase difference) and Ψ (azimuth) characterizing practical systems. In this paper, the influence of roughness of two-dimensional randomly microrough surfaces (relative roughness σ/λ ranges from 0.001 to 0.025) of silicon on ellipsometric parameters was simulated by the finite-difference time-domain method which was validated with experimental results. The effects of incident angle, relative roughness, and correlation length were numerically investigated for two-dimensional Gaussian distributed randomly microrough surfaces, respectively. The simulated results showed that compared with the smooth surface, only tiny changes of the ellipsometric parameter Δ could be observed for microrough silicon surface in the vicinity of the Brewster angle, but obviously changes of Ψ occur especially in the vicinity of the Brewster angle. More differences between the ellipsometric parameters of the rough surface and smooth surface can been seen especially in the vicinity of the Brewster angle as the relative roughness σ/λ increases or correlation length τ decreases. The results reveal that when we measure the optical constants of solid materials by ellipsometry, the smaller roughness, larger correlation length and larger incident wavelength will lead to the higher precision of measurements.

  7. The impact of lipid composition on the stability of the tear fluid lipid layer

    DEFF Research Database (Denmark)

    Kulovesi, P.; Telenius, J.; Koivuniemi, A.

    2012-01-01

    The tear fluid protects the corneal epithelium from drying and pathogens and it also provides nutrients to these cells. Tear fluid is composed of an aqueous layer as well as a lipid layer that resides at the air-tear interface. The function of the lipid layer is to lower the surface tension of th......-neutral lipid ratio. The results provide a plausible rationale for the development of dry eye syndrome in blepharitis patients.......The tear fluid protects the corneal epithelium from drying and pathogens and it also provides nutrients to these cells. Tear fluid is composed of an aqueous layer as well as a lipid layer that resides at the air-tear interface. The function of the lipid layer is to lower the surface tension...

  8. On tear film breakup (TBU): dynamics and imaging.

    Science.gov (United States)

    Braun, Richard J; Driscoll, Tobin A; Begley, Carolyn G; King-Smith, P Ewen; Siddique, Javed I

    2018-06-13

    We report the results of some recent experiments to visualize tear film dynamics. We then study a mathematical model for tear film thinning and tear film breakup (TBU), a term from the ocular surface literature. The thinning is driven by an imposed tear film thinning rate which is input from in vivo measurements. Solutes representing osmolarity and fluorescein are included in the model. Osmolarity causes osmosis from the model ocular surface, and the fluorescein is used to compute the intensity corresponding closely to in vivo observations. The imposed thinning can be either one-dimensional or axisymmetric, leading to streaks or spots of TBU, respectively. For a spatially-uniform (flat) film, osmosis would cease thinning and balance mass lost due to evaporation; for these space-dependent evaporation profiles TBU does occur because osmolarity diffuses out of the TBU into the surrounding tear film, in agreement with previous results. The intensity pattern predicted based on the fluorescein concentration is compared with the computed thickness profiles; this comparison is important for interpreting in vivo observations. The non-dimensionalization introduced leads to insight about the relative importance of the competing processes; it leads to a classification of large vs small TBU regions in which different physical effects are dominant. Many regions of TBU may be considered small, revealing that the flow inside the film has an appreciable influence on fluorescence imaging of the tear film.

  9. Energetic approach for ductile tearing

    International Nuclear Information System (INIS)

    Marie, St.

    1999-01-01

    This study focuses on ductile crack initiation and propagation. It aims to propose an approach for the engineer allowing the prediction of the evolution of cracks in large scale components, from parameters determined on laboratory specimens. A crack initiation criterion, defining a J i tenacity related to crack tip blunting proposed in the literature is validated in the study. This criterion is shown to be transferable from laboratory specimens to structures. The literature review shows that an approach based on the dissipated energy in the fracture process during propagation offers an economical and simple solution to simulate large crack growth. A numerical method is proposed to estimate this fracture energy. The existence of an energy parameter G fr is shown, by simulating the propagation by the simultaneous release of several elements and by the use of the Rice integral with an original integration path. This parameter represents the needed energy for a unit crack extension and appears to be intrinsic to the material. A global energy statement allows to relate this parameter to a variation of the plastic part of J integral. It offers a second numerical method to simulate the propagation just from stationary numerical calculations, as well as the elaboration of a simplified method. This approach, using two parameters J i and G fr , intrinsic to the material and experimentally measurable on specimens, is validated on many tests such as crack pipes subjected to four points bending and cracked rings in compression. For example, this approach allows to model up to 90 mm ductile tearing in a pipe with a circumferential through-wall crack in ferritic steel, or to anticipate the evolution of a semi-elliptical crack in an aged austenitic ferritic steel plate subjected to bending. (author)

  10. Inverse modeling of hydrologic parameters using surface flux and runoff observations in the Community Land Model

    Science.gov (United States)

    Sun, Y.; Hou, Z.; Huang, M.; Tian, F.; Leung, L. Ruby

    2013-12-01

    This study demonstrates the possibility of inverting hydrologic parameters using surface flux and runoff observations in version 4 of the Community Land Model (CLM4). Previous studies showed that surface flux and runoff calculations are sensitive to major hydrologic parameters in CLM4 over different watersheds, and illustrated the necessity and possibility of parameter calibration. Both deterministic least-square fitting and stochastic Markov-chain Monte Carlo (MCMC)-Bayesian inversion approaches are evaluated by applying them to CLM4 at selected sites with different climate and soil conditions. The unknowns to be estimated include surface and subsurface runoff generation parameters and vadose zone soil water parameters. We find that using model parameters calibrated by the sampling-based stochastic inversion approaches provides significant improvements in the model simulations compared to using default CLM4 parameter values, and that as more information comes in, the predictive intervals (ranges of posterior distributions) of the calibrated parameters become narrower. In general, parameters that are identified to be significant through sensitivity analyses and statistical tests are better calibrated than those with weak or nonlinear impacts on flux or runoff observations. Temporal resolution of observations has larger impacts on the results of inverse modeling using heat flux data than runoff data. Soil and vegetation cover have important impacts on parameter sensitivities, leading to different patterns of posterior distributions of parameters at different sites. Overall, the MCMC-Bayesian inversion approach effectively and reliably improves the simulation of CLM under different climates and environmental conditions. Bayesian model averaging of the posterior estimates with different reference acceptance probabilities can smooth the posterior distribution and provide more reliable parameter estimates, but at the expense of wider uncertainty bounds.

  11. Four-parameter model for polarization-resolved rough-surface BRDF.

    Science.gov (United States)

    Renhorn, Ingmar G E; Hallberg, Tomas; Bergström, David; Boreman, Glenn D

    2011-01-17

    A modeling procedure is demonstrated, which allows representation of polarization-resolved BRDF data using only four parameters: the real and imaginary parts of an effective refractive index with an added parameter taking grazing incidence absorption into account and an angular-scattering parameter determined from the BRDF measurement of a chosen angle of incidence, preferably close to normal incidence. These parameters allow accurate predictions of s- and p-polarized BRDF for a painted rough surface, over three decades of variation in BRDF magnitude. To characterize any particular surface of interest, the measurements required to determine these four parameters are the directional hemispherical reflectance (DHR) for s- and p-polarized input radiation and the BRDF at a selected angle of incidence. The DHR data describes the angular and polarization dependence, as well as providing the overall normalization constraint. The resulting model conserves energy and fulfills the reciprocity criteria.

  12. Geometrical influences on neoclassical magnetohydrodynamic tearing modes

    International Nuclear Information System (INIS)

    Kruger, S.E.; Hegna, C.C.; Callen, J.D.

    1997-07-01

    The influence of geometry on the pressure drives of nonideal magnetohydrodynamic tearing modes is presented. In order to study the effects of elongation, triangularity, and aspect ratio, three different machines are considered to provide a range of tokamak configurations: TFTR (circular), DIII-D (D-shaped), and Pegasus (extremely low aspect ratio). For large aspect ratio tokamaks, shaping does very little to influence the pressure gradient drives, while at low aspect ratios, a very strong sensitivity to the profiles is found. In particular, this sensitivity is connected to the strong dependence on the magnetic shear. This suggests that at low aspect ratio it may be possible to stabilize neoclassical tearing modes by flattening the q profile near low order rational surfaces (e.g., q = 2/1) using a combination of shaping and localized current drive, whereas at large aspect ratio it is more difficult

  13. Surface tension and related thermodynamic parameters of alcohols using the Traube stalagmometer

    International Nuclear Information System (INIS)

    Dilmohamud, B A; Seeneevassen, J; Rughooputh, S D D V; Ramasami, P

    2005-01-01

    An apparatus was devised using the Traube Stalagmometer for the determination of the surface tension of the alcohols methanol, ethanol, propan-1-ol and butan-1-ol. Measurements were made under atmospheric pressure at temperatures between 288.15 K and 313.15 K. The surface tension values were correlated with temperature and surface thermodynamic parameters, namely surface entropy and surface enthalpy, were also calculated. The results obtained are in agreement with the literature and they are promising for the use of this low cost arrangement for accurate measurement of surface tension. Surface tension values were obtained with a maximum error of 0.5 mN m -1 and a maximum standard deviation of 0.8 mN m -1 . We recommend this arrangement for students in advanced university courses and it can also be used for research work

  14. Modeling and Parameter Optimization for Surface Roughness and Residual Stress in Dry Turning Process

    Directory of Open Access Journals (Sweden)

    M. H. El-Axir

    2017-10-01

    Full Text Available The influence of some turning variables and tool overhang on surface roughness parameters and residual stress induced due to machining 6061-T6 aluminum alloy is investigated in this paper. Four input parameters (cutting speed, feed rate, depth of cut and tool overhang are considered. Tests are carried out by precision turning operation on a lathe. Design of experiment techniques, i.e. response surface methodology (RSM and Taguchi's technique have been used to accomplish the objective of the experimental study. Surface roughness parameters are measured using a portable surface roughness device while residual stresses are measured employing deflection-etching technique using electrochemical analysis. The results obtained reveal that feed and rotational speed play significant role in determining the average surface roughness. Furthermore, the depth of cut and tool overhang are less significant parameters, whereas tool overhang interacts with feed rate. The best result of surface roughness was obtained using low or medium values of overhang with low speed and /or feed rate. Minimum maximum tensile residual stress can be obtained with a combination of tool overhang of 37 mm with very low depth of cut, low rotational speed and feed rate of 0.188 mm/rev.

  15. Determination of Ductile Tearing Resistance Curve in Weld Joints

    International Nuclear Information System (INIS)

    Marie, S.; Gilles, P.; Ould, P.

    2010-01-01

    Steels present in the ductile domain a tearing resistance which increase with the crack propagation up to the failure. This ductile tearing resistance is in general characterised with curves giving the variation of a global parameter (opening displacement at the crack tip delta, integral J) versus the crack extension Delta a. These global approaches depend more or less on the specimen geometry and on the type of the imposed loading. Local approaches based on the description of the ductile tearing mechanisms provide reliable solution to the transferability problem (from the lab specimen to the component) but are complex and costly to use and are not codified. These problems get worse in the case of a weld joint where no standard is available for the measurement of their ductile tearing resistance. But the welded joints are often the weak point of the structure because of greater risk of defects, the heterogeneity of the microstructure of the weld, deformation along the interface between two materials with different yield stress (mismatch).... After briefly recalling the problems of transferability of the ductile tearing resistance curves obtained on lab specimen to the case of components, this article identifies the factors complicating the determination of the toughness in the welded joints and gives recommendations for the experimental determination of ductile tearing resistance curves of welded joints

  16. Modified polarimetric bidirectional reflectance distribution function with diffuse scattering: surface parameter estimation

    Science.gov (United States)

    Zhan, Hanyu; Voelz, David G.

    2016-12-01

    The polarimetric bidirectional reflectance distribution function (pBRDF) describes the relationships between incident and scattered Stokes parameters, but the familiar surface-only microfacet pBRDF cannot capture diffuse scattering contributions and depolarization phenomena. We propose a modified pBRDF model with a diffuse scattering component developed from the Kubelka-Munk and Le Hors et al. theories, and apply it in the development of a method to jointly estimate refractive index, slope variance, and diffuse scattering parameters from a series of Stokes parameter measurements of a surface. An application of the model and estimation approach to experimental data published by Priest and Meier shows improved correspondence with measurements of normalized Mueller matrix elements. By converting the Stokes/Mueller calculus formulation of the model to a degree of polarization (DOP) description, the estimation results of the parameters from measured DOP values are found to be consistent with a previous DOP model and results.

  17. Software measurement standards for areal surface texture parameters: part 2—comparison of software

    International Nuclear Information System (INIS)

    Harris, P M; Smith, I M; Giusca, C; Leach, R K; Wang, C

    2012-01-01

    A companion paper in this issue describes reference software for the evaluation of areal surface texture parameters, focusing on the definitions of the parameters and giving details of the numerical algorithms employed in the software to implement those definitions. The reference software is used as a benchmark against which software in a measuring instrument can be compared. A data set is used as input to both the software under test and the reference software, and the results delivered by the software under test are compared with those provided by the reference software. This paper presents a comparison of the results returned by the reference software with those reported by proprietary software for surface texture measurement. Differences between the results can be used to identify where algorithms and software for evaluating the parameters differ. They might also be helpful in identifying where parameters are not sufficiently well-defined in standards. (paper)

  18. Meniscal Tear Film Fluid Dynamics Near Marx’s Line

    KAUST Repository

    Zubkov, V. S.

    2013-07-03

    Extensive studies have explored the dynamics of the ocular surface fluid, though theoretical investigations are typically limited to the use of the lubrication approximation, which is not guaranteed to be uniformly valid a-priori throughout the tear meniscus. However, resolving tear film behaviour within the meniscus and especially its apices is required to characterise the flow dynamics where the tear film is especially thin, and thus most susceptible to evaporatively induced hyperosmolarity and subsequent epithelial damage. Hence, we have explored the accuracy of the standard lubrication approximation for the tear film by explicit comparisons with the 2D Navier-Stokes model, considering both stationary and moving eyelids. Our results demonstrate that the lubrication model is qualitatively accurate except in the vicinity of the eyelids. In particular, and in contrast to lubrication theory, the solution of the full Navier-Stokes equations predict a distinct absence of fluid flow, and thus convective mixing in the region adjacent to the tear film contact line. These observations not only support emergent hypotheses concerning the formation of Marx\\'s line, a region of epithelial cell staining adjacent to the contact line on the eyelid, but also enhance our understanding of the pathophysiological consequences of the flow profile near the tear film contact line. © 2013 Society for Mathematical Biology.

  19. Role of roughness parameters on the tribology of randomly nano-textured silicon surface.

    Science.gov (United States)

    Gualtieri, E; Pugno, N; Rota, A; Spagni, A; Lepore, E; Valeri, S

    2011-10-01

    This experimental work is oriented to give a contribution to the knowledge of the relationship among surface roughness parameters and tribological properties of lubricated surfaces; it is well known that these surface properties are strictly related, but a complete comprehension of such correlations is still far to be reached. For this purpose, a mechanical polishing procedure was optimized in order to induce different, but well controlled, morphologies on Si(100) surfaces. The use of different abrasive papers and slurries enabled the formation of a wide spectrum of topographical irregularities (from the submicro- to the nano-scale) and a broad range of surface profiles. An AFM-based morphological and topographical campaign was carried out to characterize each silicon rough surface through a set of parameters. Samples were subsequently water lubricated and tribologically characterized through ball-on-disk tribometer measurements. Indeed, the wettability of each surface was investigated by measuring the water droplet contact angle, that revealed a hydrophilic character for all the surfaces, even if no clear correlation with roughness emerged. Nevertheless, this observation brings input to the purpose, as it allows to exclude that the differences in surface profile affect lubrication. So it is possible to link the dynamic friction coefficient of rough Si samples exclusively to the opportune set of surface roughness parameters that can exhaustively describe both height amplitude variations (Ra, Rdq) and profile periodicity (Rsk, Rku, Ic) that influence asperity-asperity interactions and hydrodynamic lift in different ways. For this main reason they cannot be treated separately, but with dependent approach through which it was possible to explain even counter intuitive results: the unexpected decreasing of friction coefficient with increasing Ra is justifiable by a more consistent increasing of kurtosis Rku.

  20. Observations on Mode I ductile tearing in sheet metals

    DEFF Research Database (Denmark)

    El-Naaman, Salim Abdallah; Nielsen, Kim Lau

    2013-01-01

    Cracked ductile sheet metals, subject to Mode I tearing, have been observed to display a variety of fracture surface morphologies depending on the material properties, and a range of studies on the fracture surface appearance have been published in the literature. Whereas classical fractures...

  1. The effect of welding parameters on surface quality of AA6351 aluminium alloy

    International Nuclear Information System (INIS)

    Yacob, S; Ariffin, N; Ali, R; Arshad, A; Wahab, M I A; Ismail, S A; Roji, NS M; Din, W B W; Zakaria, M H; Abdullah, A; Yusof, M I; Kamarulzaman, K Z; Mahyuddin, A; Hamzah, M N; Roslan, R; MAli, M A; Ahsan, Q

    2015-01-01

    In the present work, the effects of gas metal arc welding-cold metal transfer (GMAW-CMT) parameters on surface roughness are experimentally assessed. The purpose of this study is to develop a better understanding of the effects of welding speed, material thickness and contact tip to work distance on the surface roughness. Experiments are conducted using single pass gas metal arc welding-cold metal transfer (GMAW-CMT) welding technique to join the material. The material used in this experiment was AA6351 aluminum alloy with the thickness of 5mm and 6mm. A Mahr Marsuft XR 20 machine was used to measure the average roughness (Ra) of AA6351 joints. The main and interaction effect analysis was carried out to identify process parameters that affect the surface roughness. The results show that all the input process parameters affect the surface roughness of AA6351 joints. Additionally, the average roughness (Ra) results also show a decreasing trend with increased of welding speed. It is proven that gas metal arc welding-cold metal transfer (GMAW-CMT)welding process has been successful in term of providing weld joint of good surface quality for AA6351 based on the low value surface roughness condition obtained in this setup. The outcome of this experimental shall be valuable for future fabrication process in order to obtained high good quality weld. (paper)

  2. Interaction of lysozyme with a tear film lipid layer model: A molecular dynamics simulation study.

    Science.gov (United States)

    Wizert, Alicja; Iskander, D Robert; Cwiklik, Lukasz

    2017-12-01

    The tear film is a thin multilayered structure covering the cornea. Its outermost layer is a lipid film underneath of which resides on an aqueous layer. This tear film lipid layer (TFLL) is itself a complex structure, formed by both polar and nonpolar lipids. It was recently suggested that due to tear film dynamics, TFLL contains inhomogeneities in the form of polar lipid aggregates. The aqueous phase of tear film contains lachrymal-origin proteins, whereby lysozyme is the most abundant. These proteins can alter TFLL properties, mainly by reducing its surface tension. However, a detailed nature of protein-lipid interactions in tear film is not known. We investigate the interactions of lysozyme with TFLL in molecular details by employing coarse-grained molecular dynamics simulations. We demonstrate that lysozyme, due to lateral restructuring of TFLL, is able to penetrate the tear lipid film embedded in inverse micellar aggregates. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. The Impact of Ceramic Shell Strength on Hot Tearing during Investment Casting

    International Nuclear Information System (INIS)

    Norouzi, Saeid; Farhangi, Hassan

    2011-01-01

    The effect of ceramic shell strength on hot tearing susceptibility during solidification was inspected practicing investment casting of the cobalt-base superalloy samples with the same casting conditions, but different ceramic shell systems. Results showed that the lower the ceramic shell strength upon using polymer additives, the lower the hindered contraction rate, and the lower the hindered contraction rate, the smaller the hot tearing tendency. Optical microscopy and electron microscopy scanning revealed that the hot tear propagated along the last solidified interdendritic phase, and that the hot tear surface had two major modes: 1) the ductile region in the outer layer; and 2) the inner region of liquid embrittlement.

  4. Effects of electron cyclotron current drive on the evolution of double tearing mode

    International Nuclear Information System (INIS)

    Sun, Guanglan; Dong, Chunying; Duan, Longfang

    2015-01-01

    The effects of electron cyclotron current drive (ECCD) on the double tearing mode (DTM) in slab geometry are investigated by using two-dimensional compressible magnetohydrodynamics equations. It is found that, mainly, the double tearing mode is suppressed by the emergence of the secondary island, due to the deposition of driven current on the X-point of magnetic island at one rational surface, which forms a new non-complete symmetric magnetic topology structure (defined as a non-complete symmetric structure, NSS). The effects of driven current with different parameters (magnitude, initial time of deposition, duration time, and location of deposition) on the evolution of DTM are analyzed elaborately. The optimal magnitude or optimal deposition duration of driven current is the one which makes the duration of NSS the longest, which depends on the mutual effect between ECCD and the background plasma. Moreover, driven current introduced at the early Sweet-Parker phase has the best suppression effect; and the optimal moment also exists, depending on the duration of the NSS. Finally, the effects varied by the driven current disposition location are studied. It is verified that the favorable location of driven current is the X-point which is completely different from the result of single tearing mode

  5. Effects of electron cyclotron current drive on the evolution of double tearing mode

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Guanglan, E-mail: sunguanglan@nciae.edu.cn; Dong, Chunying [Basic Science Section, North China Institute of Aerospace Engineering, Langfang 065000 (China); Duan, Longfang [School of Computer and Remote Sensing Information Technology, North China Institute of Aerospace Engineering, Langfang 065000 (China)

    2015-09-15

    The effects of electron cyclotron current drive (ECCD) on the double tearing mode (DTM) in slab geometry are investigated by using two-dimensional compressible magnetohydrodynamics equations. It is found that, mainly, the double tearing mode is suppressed by the emergence of the secondary island, due to the deposition of driven current on the X-point of magnetic island at one rational surface, which forms a new non-complete symmetric magnetic topology structure (defined as a non-complete symmetric structure, NSS). The effects of driven current with different parameters (magnitude, initial time of deposition, duration time, and location of deposition) on the evolution of DTM are analyzed elaborately. The optimal magnitude or optimal deposition duration of driven current is the one which makes the duration of NSS the longest, which depends on the mutual effect between ECCD and the background plasma. Moreover, driven current introduced at the early Sweet-Parker phase has the best suppression effect; and the optimal moment also exists, depending on the duration of the NSS. Finally, the effects varied by the driven current disposition location are studied. It is verified that the favorable location of driven current is the X-point which is completely different from the result of single tearing mode.

  6. Optimisation of process parameters on thin shell part using response surface methodology (RSM)

    Science.gov (United States)

    Faiz, J. M.; Shayfull, Z.; Nasir, S. M.; Fathullah, M.; Rashidi, M. M.

    2017-09-01

    This study is carried out to focus on optimisation of process parameters by simulation using Autodesk Moldflow Insight (AMI) software. The process parameters are taken as the input in order to analyse the warpage value which is the output in this study. There are some significant parameters that have been used which are melt temperature, mould temperature, packing pressure, and cooling time. A plastic part made of Polypropylene (PP) has been selected as the study part. Optimisation of process parameters is applied in Design Expert software with the aim to minimise the obtained warpage value. Response Surface Methodology (RSM) has been applied in this study together with Analysis of Variance (ANOVA) in order to investigate the interactions between parameters that are significant to the warpage value. Thus, the optimised warpage value can be obtained using the model designed using RSM due to its minimum error value. This study comes out with the warpage value improved by using RSM.

  7. Magnetic tearing in plasma focus

    International Nuclear Information System (INIS)

    Sharkawy, W.

    1994-01-01

    A plasma focus device used is Mather type filled with hydrogen gas at pressure between 0.1 and 1 torr. When connected to a large capacitor ≤10 KV a discharge is started with peak current 100 KA. Under the influence of the radial electric field E r , due to the potential between electrodes, and B φ the plasma will drift in the axial direction with velocity cE r /B φ . An induced axial magnetic field B z has been detected which due to sheath velocity. A propagation of magnetosonic wave has been observed with velocity ≅10 3 m sec -1 . Such a wave might be excited when the magnetic pressure is much greater than the plasma kinetic pressure B 2 /8π>nKT. Assuming (MHD) to be stable, Tearing model was driven which generally has smaller growth rates than (MHD) modes. Using the designed theoretical model and the plasma parameters the electron energy dΦ/dt=Ba 2 /τ R was calculated to be 2.22 KeV, which is comparable with that detected from X-ray measurements. (author)

  8. Modeling of Neoclassical Tearing Mode Stability for Generalized Toroidal Geometry

    International Nuclear Information System (INIS)

    A.L. Rosenberg; D.A. Gates; A. Pletzer; J.E. Menard; S.E. Kruger; C.C. Hegna; F. Paoletti; S. Sabbagh

    2002-01-01

    Neoclassical tearing modes (NTMs) can lead to disruption and loss of confinement. Previous analysis of these modes used large aspect ratio, low beta (plasma pressure/magnetic pressure) approximations to determine the effect of NTMs on tokamak plasmas. A more accurate tool is needed to predict the onset of these instabilities. As a follow-up to recent theoretical work, a code has been written which computes the tearing mode island growth rate for arbitrary tokamak geometry. It calls PEST-3 [A. Pletzer et al., J. Comput. Phys. 115, 530 (1994)] to compute delta prime, the resistive magnetohydrodynamic (MHD) matching parameter. The code also calls the FLUXGRID routines in NIMROD [A.H. Glasser et al., Plasma Phys. Controlled Fusion 41, A747 (1999)] for Dnc, DI and DR [C.C. Hegna, Phys. Plasmas 6, 3980 (1999); A.H. Glasser et al., Phys. Fluids 18, 875 (1975)], which are the bootstrap current driven term and the ideal and resistive interchange mode criterion, respectively. In addition to these components, the NIMROD routines calculate alphas-H, a new correction to the Pfirsch-Schlter term. Finite parallel transport effects were added and a National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 (2000)] equilibrium was analyzed. Another program takes the output of PEST-3 and allows the user to specify the rational surface, island width, and amount of detail near the perturbed surface to visualize the total helical flux. The results of this work will determine the stability of NTMs in an spherical torus (ST) [Y.-K.M. Peng et al., Nucl. Fusion 26, 769 (1986)] plasma with greater accuracy than previously achieved

  9. Effectiveness of Combined Tear Film Therapy in Patients with Evaporative Dry Eye with Short Tear Film Breakup Time.

    Science.gov (United States)

    Kim, Yung Hui; Kang, Yeon Soo; Lee, Hyo Seok; Choi, Won; You, In Cheon; Yoon, Kyung Chul

    2017-10-01

    The aim of this study was to evaluate the effectiveness of combined tear film therapy targeted to aqueous, mucin, and lipid layers in patients with refractory evaporative dry eye (EDE) with short tear film breakup time (TBUT). The patients who had EDE with short TBUT and severe symptoms refractory to artificial tears were treated with hyaluronic acid (HA) 0.15% and diquafosol tetrasodium (DQS) 3% (Group 1), HA and carbomer-based lipid-containing eyedrops (Liposic EDO Gel, LPO) (Group 2), or HA, DQS, and LPO (Group 3). Ocular Surface Disease Index (OSDI) score, visual analog scale (VAS) symptom score, TBUT, Schirmer score, and corneal and conjunctival staining scores were evaluated, and noninvasive tear film breakup time (NIBUT) and tear meniscus height were measured using Keratograph ® 5 M before and 1 and 3 months after treatment. OSDI scores, VAS scores, TBUT, and NIBUT were improved at 1 and 3 months after treatment in all groups (all P film layers was most effective in improving ocular symptoms and tear film quality.

  10. Stability of short wavelength tearing and twisting modes

    International Nuclear Information System (INIS)

    Waelbroeck, F.L.

    1998-01-01

    The stability and mutual interaction of tearing and twisting modes in a torus is governed by matrices that generalize the well-known Δ' stability index. The diagonal elements of these matrices determine the intrinsic stability of modes that reconnect the magnetic field at a single resonant surface. The off-diagonal elements indicate the strength of the coupling between the different modes. The author shows how the elements of these matrices can be evaluated, in the limit of short wavelength, from the free energy driving radially extended ballooning modes. The author applies the results by calculating the tearing and twisting Δ' for a model high-beta equilibrium with circular flux surfaces

  11. Electron diamagnetism and toroidal coupling of tearing modes

    International Nuclear Information System (INIS)

    Cowley, S.C.; Hastie, R.J.

    1987-10-01

    Using a simple model for the layer of the tearing mode, we demonstrate that toroidally coupled tearing modes with two rational surfaces are most unstable when the ω*'s of the electrons at the rational surfaces are equal. The onset of instability may then occur because of the tuning of ω* rather than the passage of Δ'-like quantities through zero. This mechanism for the onset of instability is sharp since the resonance is narrow. The effect of toroidal rotation is also discussed. 7 refs., 2 figs

  12. Statistical analysis of surface roughness in turning based on cutting parameters and tool vibrations with response surface methodology (RSM)

    Science.gov (United States)

    Touati, Soufiane; Mekhilef, Slimane

    2018-03-01

    In this paper, we present an experimental study to determine the effect of the cutting conditions and tool vibration on the surface roughness in finish turning of 32CrMoV12-28 steel, using carbide cutting tool YT15. For these purposes, a linear quadratic model in interaction of connecting surface roughness (Ra, Rz) with different combinations of cutting parameters such as cutting speed, feed rate, depth of cut and tool vibration, in radial and in tangential cutting force directions (Vy) and (Vz) is elaborated. In order to express the degree of interaction of cutting parameters and tool vibration, a multiple linear regression and response surface methodology are adopted. The application of this statistical technique for predicting the surface roughness shows that the feed rate is the most dominant factor followed by the cutting speed. However, the depth of the cut and tool vibrations have secondary effect. The presented models have some interest since they are used in the cutting process optimization.

  13. Optimisation of wire-cut EDM process parameter by Grey-based response surface methodology

    Science.gov (United States)

    Kumar, Amit; Soota, Tarun; Kumar, Jitendra

    2018-03-01

    Wire electric discharge machining (WEDM) is one of the advanced machining processes. Response surface methodology coupled with Grey relation analysis method has been proposed and used to optimise the machining parameters of WEDM. A face centred cubic design is used for conducting experiments on high speed steel (HSS) M2 grade workpiece material. The regression model of significant factors such as pulse-on time, pulse-off time, peak current, and wire feed is considered for optimising the responses variables material removal rate (MRR), surface roughness and Kerf width. The optimal condition of the machining parameter was obtained using the Grey relation grade. ANOVA is applied to determine significance of the input parameters for optimising the Grey relation grade.

  14. MRI diagnosis of meniscal tears

    International Nuclear Information System (INIS)

    Kuga, Naoyuki; Oh, Toshihiro

    1996-01-01

    We studied the accuracy of magnetic resonance imaging (MRI) of the knee in fifty-six patients who were also examined arthroscopically. The accuracy, sensitivity, and specificity were 96%, 100%, and 95% for medial meniscal tears, and 91%, 67%, and 100% for lateral meniscal tears respectively. Two MRIs of the medial meniscus were false-positives. These MRI findings were both meniscocapsular separation of the medial meniscus, but the arthroscopic findings were normal. One case was an ACL injury and the other PCL and MCL injury. Hemorrhage and edema of the medial capsule caused by valgus stress at injury may look like a meniscal pseudo-tear on MRI. Five MRIs of the lateral meniscus were false-negatives. All menisci showed normal signal and shape on MRI but traumatic and stable tears of the lateral meniscus were identified arthroscopically. All were associated with ACL tears and lateral condylar bone bruise. The traumatic and stable tear of the meniscus tended to be overlooked on MRI because a meniscus without degeneration shows a normal signal. (author)

  15. Parameters of the center of pressure displacement on the saddle during hippotherapy on different surfaces

    Directory of Open Access Journals (Sweden)

    Fabiana M. Flores

    2015-06-01

    Full Text Available Background: Hippotherapy uses horseback riding movements for therapeutic purposes. In addition to the horse's movement, the choice of equipment and types of floor are also useful in the intervention. The quantification of dynamic parameters that define the interaction of the surface of contact between horse and rider provides insight into how the type of floor surface variations act upon the subject's postural control. Objective: To test whether different types of surfaces promote changes in the amplitude (ACOP and velocity (VCOP of the center of pressure (COP displacement during the rider's contact with the saddle on the horse's back. Method: Twenty two healthy adult male subjects with experience in riding were evaluated. The penetration resistances of asphalt, sand and grass surfaces were measured. The COP data were collected on the three surfaces using a pressure measurement mat. Results: ACOP values were higher in sand, followed by grass and asphalt, with significant differences between sand and asphalt (anteroposterior, p=0.042; mediolateral, p=0.019. The ACOP and VCOP values were higher in the anteroposterior than in the mediolateral direction on all surfaces (ACOP, p=0.001; VCOP, p=0.006. The VCOP did not differ between the surfaces. Conclusion: Postural control, measured by the COP displacement, undergoes variations in its amplitude as a result of the type of floor surface. Therefore, these results reinforce the importance of the choice of floor surface when defining the strategy to be used during hippotherapy intervention.

  16. Parameters of the center of pressure displacement on the saddle during hippotherapy on different surfaces.

    Science.gov (United States)

    Flores, Fabiana M; Dagnese, Frederico; Mota, Carlos B; Copetti, Fernando

    2015-01-01

    Hippotherapy uses horseback riding movements for therapeutic purposes. In addition to the horse's movement, the choice of equipment and types of floor are also useful in the intervention. The quantification of dynamic parameters that define the interaction of the surface of contact between horse and rider provides insight into how the type of floor surface variations act upon the subject's postural control. To test whether different types of surfaces promote changes in the amplitude (ACOP) and velocity (VCOP) of the center of pressure (COP) displacement during the rider's contact with the saddle on the horse's back. Twenty two healthy adult male subjects with experience in riding were evaluated. The penetration resistances of asphalt, sand and grass surfaces were measured. The COP data were collected on the three surfaces using a pressure measurement mat. ACOP values were higher in sand, followed by grass and asphalt, with significant differences between sand and asphalt (anteroposterior, p=0.042; mediolateral, p=0.019). The ACOP and VCOP values were higher in the anteroposterior than in the mediolateral direction on all surfaces (ACOP, p=0.001; VCOP, p=0.006). The VCOP did not differ between the surfaces. Postural control, measured by the COP displacement, undergoes variations in its amplitude as a result of the type of floor surface. Therefore, these results reinforce the importance of the choice of floor surface when defining the strategy to be used during hippotherapy intervention.

  17. Pele's tears and spheres: Examples from Kilauea Iki

    Science.gov (United States)

    Porritt, L. A.; Russell, J. K.; Quane, S. L.

    2012-06-01

    Pele's tears are a well known curiosity commonly associated with low viscosity basaltic explosive eruptions. However, detailed studies of these pyroclasts are rare and, thus, there is no full explanation for their formation. These intriguing pyroclasts have smooth glassy surfaces, vesiculated interiors (∼30%), and fluidal morphologies trending towards teardrops and then spheres as they decrease in size to Pele's tears from the 1959 fire-fountaining eruption of Kilauea Iki has led to a reassessment of the mechanisms of magma disruption and fragmentation, timescales of relaxation, and cooling rates that are responsible for their formation. We conclude that the particle size distributions and vesicularities of Pele's tears are representative of the magma properties at the moment of explosive disruption. However, the morphology of these unique pyroclasts results from reshaping through viscous relaxation, driven by surface tension forces, on a time scale fast enough to compete with cooling times.

  18. Comparison of Tear Osmolarity in Rheumatoid Arthritis Patients With and Without Secondary Sjogren Syndrome.

    Science.gov (United States)

    Ng, Alex L K; Choy, Bonnie N K; Chan, Tommy C Y; Wong, Ian Y H; Lai, Jimmy S M; Mok, Mo Yin

    2017-07-01

    To compare tear osmolarity (TO) and other dry eye parameters in rheumatoid arthritis (RA) patients with or without secondary Sjogren syndrome (sSS). Consecutive patients with RA were divided into a sSS group and no-sSS group using conventional diagnostic criteria by rheumatologists using symptomatology, Schirmer test score, and anti-Ro or anti-La autoantibody status. The TO, Ocular Surface Disease Index, dry eye disease (DED) parameters [such as tear breakup time (TBUT) and corneal staining score] and the systemic inflammatory markers [erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP)] were compared. Correlation analyses between TO and the DED parameters and inflammatory markers were also performed. A total of 42 cases with mean age 54.8 ± 12.3 were included, with 12 patients (29%) having sSS and 30 (71%) without sSS. TO was increased in both groups (329 ± 20 and 319 ± 25 mOsm/L, respectively), but no statistically significant difference was found between the 2 groups (P = 0.126). RA with sSS had significantly shorter TBUT, higher corneal staining score, and ESR CRP levels (P sSS. There was no significant correlation between TO and the Schirmer test score, and the physician could not use TO to diagnose sSS. However, TO correlated well with both DED parameters (TBUT and corneal staining score) and systemic inflammatory markers (ESR and CRP).

  19. Effect of processing parameters of rotary ultrasonic machining on surface integrity of potassium dihydrogen phosphate crystals

    Directory of Open Access Journals (Sweden)

    Jianfu Zhang

    2015-09-01

    Full Text Available Potassium dihydrogen phosphate is an important optical crystal. However, high-precision processing of large potassium dihydrogen phosphate crystal workpieces is difficult. In this article, surface roughness and subsurface damage characteristics of a (001 potassium dihydrogen phosphate crystal surface produced by traditional and rotary ultrasonic machining are studied. The influence of process parameters, including spindle speed, feed speed, type and size of sintered diamond wheel, ultrasonic power, and selection of cutting fluid on potassium dihydrogen phosphate crystal surface integrity, was analyzed. The surface integrity, especially the subsurface damage depth, was affected significantly by the ultrasonic power. Metal-sintered diamond tools with high granularity were most suitable for machining potassium dihydrogen phosphate crystal. Cutting fluid played a key role in potassium dihydrogen phosphate crystal machining. A more precise surface can be obtained in machining with a higher spindle speed, lower feed speed, and using kerosene as cutting fluid. Based on the provided optimized process parameters for machining potassium dihydrogen phosphate crystal, a processed surface quality with Ra value of 33 nm and subsurface damage depth value of 6.38 μm was achieved.

  20. Examination of rotator cuff re-tear

    International Nuclear Information System (INIS)

    Kitahara, Hiroyuki; Yabe, Yoshihiro; Norimatsu, Takahiro; Adachi, Shinji; Sera, Keisuke

    2010-01-01

    The six-month post-operative re-tear rate in 72 arthroscopic rotator cuff repair cases was 16.3% by MRI. The re-tear rate of massive tears was 50%. We investigated the details of the re-tears by MRI and arthroscopic findings. High re-tear rates were connected with cuff tear size and fatty degeneration of muscle belly. Cases with poor cuff quality in arthroscopically showed high re-tear rate. These results suggest that surgery operation should be performed as soon as possible after diagnosis of cuff tear to obtain good results. Cases with damage of long head of the biceps (LHB) are likely to develop impingement causes of re-tears. Some type of rehabilitation is required to avoid impingement in such cases. (author)

  1. Cytokine and chemokine levels in tears from healthy subjects.

    Science.gov (United States)

    Carreño, Ester; Enríquez-de-Salamanca, Amalia; Tesón, Marisa; García-Vázquez, Carmen; Stern, Michael E; Whitcup, Scott M; Calonge, Margarita

    2010-11-01

    There is growing evidence for the existence of an 'immune tone' in normal tears. The aim of this study was to determine the levels of a large panel of cytokines and chemokines in tears obtained from healthy subjects. These levels can then serve as baseline values for comparison with patients suffering from ocular surface diseases. Nine healthy subjects participated in this study, and normal ocular surface health was documented by the results of a dry eye questionnaire, Schirmer strip wetting, and vital staining of the cornea. Four microliters of tears were collected from each eye and analysed separately with multiplex bead-based assays for the concentration of 30 cytokines and chemokines. Twenty-five cytokines/chemokines were detected. CCL11/Eotaxin1, GM-CSF, G-CSF, IFN-γ, IL-2, IL-3, IL-4, IL-5, IL-10, IL-13, IL-12p70, IL-15, CX3CL1/Fractalkine, TNF-α, epidermal growth factor, and CCL4/MIP-1β were present at 5-100 pg/ml. IL-1β, IL-6, IL-7A, CXCL8/IL-8, and CCL2/MCP-1 were present at 100-400 pg/ml. IL-1Ra, CXCL10/IP-10 and vascular endothelial growth factor were present at more than 1000 pg/ml. Multiplex bead-based assays are convenient for cytokine/chemokine detection in tears. Fracktalkine has been detected in human healthy tears for the first time. The knowledge of cytokine/chemokine concentrations in tears from normal subjects is an important reference for further comparison with patients suffering from ocular surface diseases. Variability in their levels can reflect a phenomenon of potential importance for the understanding of the ocular surface cytokine pattern. © 2010 The Authors. Journal compilation © 2010 Acta Ophthalmol.

  2. The effect of machining parameters on surface roughness during turning of stainless steel

    International Nuclear Information System (INIS)

    El-Belazi, Khalid M.

    1991-03-01

    Surface roughness is a direct consequence of the cutting tool action, its assessment and control represent an effective way by which the machining process can be studied. The control of surface roughness has become increasingly important during the last thirty years, because the quality of surface is extremely important for machined components that have been designed to stand to static and cyclic loads. This work has two major goals. The first is to develop a new theoretical model based on the assumption that the shape of the cutting tool nose is elliptical to evaluate the surface roughness parameters. The second is to investigate the effect of cutting speed, feed rate, overhang length, tool nose radius (circular sharp), and depth of cut on surface roughness of turned surfaces of austenitic stainless steel grade 12X18H10T. It was found from the theoretical part that the surface roughness values obtained from the elliptical model are much better than those obtained from the other models. It was found from the experimental work that the surface roughness values increase by increasing cutting speed, feed rate, depth of cut, and overhang length, and fluctuates when using cutting tools with various nose radii, during turning of the above mentioned steel by using a brazed carbide cutting tool. (author)

  3. Surface density: a new parameter in the fundamental metallicity relation of star-forming galaxies

    Science.gov (United States)

    Hashimoto, Tetsuya; Goto, Tomotsugu; Momose, Rieko

    2018-04-01

    Star-forming galaxies display a close relation among stellar mass, metallicity, and star formation rate (or molecular-gas mass). This is known as the fundamental metallicity relation (FMR) (or molecular-gas FMR), and it has a profound implication on models of galaxy evolution. However, there still remains a significant residual scatter around the FMR. We show here that a fourth parameter, the surface density of stellar mass, reduces the dispersion around the molecular-gas FMR. In a principal component analysis of 29 physical parameters of 41 338 star-forming galaxies, the surface density of stellar mass is found to be the fourth most important parameter. The new 4D fundamental relation forms a tighter hypersurface that reduces the metallicity dispersion to 50 per cent of that of the molecular-gas FMR. We suggest that future analyses and models of galaxy evolution should consider the FMR in a 4D space that includes surface density. The dilution time-scale of gas inflow and the star-formation efficiency could explain the observational dependence on surface density of stellar mass.

  4. The influence of land surface parameters on energy flux densities derived from remote sensing data

    Energy Technology Data Exchange (ETDEWEB)

    Tittebrand, A.; Schwiebus, A. [Inst. for Hydrology und Meteorology, TU Dresden (Germany); Berger, F.H. [Observatory Lindenberg, German Weather Service, Lindenberg (Germany)

    2005-04-01

    Knowledge of the vegetation properties surface reflectance, normalised difference vegetation index (NDVI) and leaf area index (LAI) are essential for the determination of the heat and water fluxes between terrestrial ecosystems and the atmosphere. Remote sensing data can be used to derive spatial estimates of the required surface properties. The determination of land surface parameters and their influence on radiant and energy flux densities is investigated with data of different remote sensing systems. Sensitivity studies show the importance of correctly derived land surface properties to estimate the key quantity of the hydrological cycle, the evapotranspiration (L.E), most exactly. In addition to variable parameters like LAI or NDVI there are also parameters which are can not be inferred from satellite data but needed for the Penman-Monteith approach. Fixed values are assumed for these variables because they have little influence on L.E. Data of Landsat-7 ETM+ and NOAA-16 AVHRR are used to show results in different spatial resolution. The satellite derived results are compared with ground truth data provided by the Observatory Lindenberg of the German Weather Service. (orig.)

  5. Influence of autoclave sterilization on the surface parameters and mechanical properties of six orthodontic wires.

    Science.gov (United States)

    Pernier, C; Grosgogeat, B; Ponsonnet, L; Benay, G; Lissac, M

    2005-02-01

    Orthodontic wires are frequently packaged in individual sealed bags in order to avoid cross-contamination. The instructions on the wrapper generally advise autoclave sterilization of the package and its contents if additional protection is desired. However, sterilization can modify the surface parameters and the mechanical properties of many types of material. The aim of this research was to determine the influence of one of the most widely used sterilization processes, autoclaving (18 minutes at 134 degrees C, as recommended by the French Ministry of Health), on the surface parameters and mechanical properties of six wires currently used in orthodontics (one stainless steel alloy: Tru-Chrome RMO; two nickel-titanium shape memory alloys: Neo Sentalloy and Neo Sentalloy with Ionguard GAC; and three titanium-molybdenum alloys: TMA(R) and Low Friction TMA Ormco and Resolve GAC). The alloys were analysed on receipt and after sterilization, using surface structure observation techniques, including optical, scanning electron and atomic force microscopy and profilometry. The mechanical properties were assessed by three-point bending tests. The results showed that autoclave sterilization had no adverse effects on the surface parameters or on the selected mechanical properties. This supports the possibility for practitioners to systematically sterilize wires before placing them in the oral environment.

  6. The influence of toroidicity, pressure and local profile changes on tearing mode stability

    International Nuclear Information System (INIS)

    Connor, J.W.; Hastie, R.J.; Martin, T.J.; Cowley, S.C.

    1992-01-01

    Tearing modes appear to play a significant role in determining Tokamak behaviour. In high temperature plasmas realistic plasma models for the response at the resonant magnetic surfaces necessitate the use of asymptotic matching methods (the Δ' formulation) in calculations of linear stability and non-linear saturation. These calculations are complicated by toroidal and surface shape effects which cause coupling of different poloidal harmonics in a tearing mode. This leads to coupling of tearing modes centred on different resonant surfaces. However, when diamagnetic effects and sheared equilibrium flows are taken into account theory predicts that tearing will occur at only one surface. At all other surfaces the plasma response is determined by the ideal inertial equations. As a first approximation we treat this as infinite, and calculate the scalar Δ' m/n associated with one resonant surface at a time. (author) 8 refs., 2 figs., 2 tabs

  7. Investigation of helium plasma stream parameters in experiments on surface modification

    International Nuclear Information System (INIS)

    Bandura, A.N.; Byrka, O.V.; Chebotarev, V.V.; Garkusha, I.E.; Tsarenko, A.V. and eds.

    2005-01-01

    The main objection of this study is adjustment of plasma treatment regimes for different materials that allows achieving optimal thickness of modified layer with simultaneously minimal value of surface roughness. With use of optical spectroscopy, detailed information about the basic plasma parameters - electron density, electron and ion temperatures, plasma stream duration and velocity, was obtained. Integrated spectra of plasma radiation were analyzed. The majority of helium and impurity spectral lines were investigated on a subject of Stark broadening. Plasma pressure and energy density values measured with piezodetectors and calorimeters are in good agreement with plasma parameters obtained by optical techniques

  8. Wavelet theory and belt finishing process, influence of wavelet shape on the surface roughness parameter values

    International Nuclear Information System (INIS)

    Khawaja, Z; Mazeran, P-E; Bigerelle, M; Guillemot, G; Mansori, M El

    2011-01-01

    This article presents a multi-scale theory based on wavelet decomposition to characterize the evolution of roughness in relation with a finishing process or an observed surface property. To verify this approach in production conditions, analyses were developed for the finishing process of the hardened steel by abrasive belts. These conditions are described by seven parameters considered in the Tagushi experimental design. The main objective of this work is to identify the most relevant roughness parameter and characteristic length allowing to assess the influence of finishing process, and to test the relevance of the measurement scale. Results show that wavelet approach allows finding this scale.

  9. Process parameter and surface morphology of pineapple leaf electrospun nanofibers (PALF)

    Science.gov (United States)

    Surip, S. N.; Aziz, F. M. A.; Bonnia, N. N.; Sekak, K. A.; Zakaria, M. N.

    2017-09-01

    In recent times, nanofibers have attracted the attention of researchers due to their pronounced micro and nano structural characteristics that enable the development of advanced materials that have sophisticated applications. The production of nanofibers by the electrospinning process is influenced both by the electrostatic forces and the viscoelastic behavior of the polymer. Process parameters, like solution feed rate, applied voltage, nozzle-collector distance, and spinning environment, and material properties, like solution concentration, viscosity, surface tension, conductivity, and solvent vapor pressure, influence the structure and properties of electrospun nanofibers. Significant work has been done to characterize the properties of PALF nanofibers as a function of process and material parameters.

  10. Comparison of segmentation techniques to determine the geometric parameters of structured surfaces

    International Nuclear Information System (INIS)

    MacAulay, Gavin D; Giusca, Claudiu L; Leach, Richard K; Senin, Nicola

    2014-01-01

    Structured surfaces, defined as surfaces characterized by topography features whose shape is defined by design specifications, are increasingly being used in industry for a variety of applications, including improving the tribological properties of surfaces. However, characterization of such surfaces still remains an issue. Techniques have been recently proposed, based on identifying and extracting the relevant features from a structured surface so they can be verified individually, using methods derived from those commonly applied to standard-sized parts. Such emerging approaches show promise but are generally complex and characterized by multiple data processing steps making performance difficult to assess. This paper focuses on the segmentation step, i.e. partitioning the topography so that the relevant features can be separated from the background. Segmentation is key for defining the geometric boundaries of the individual feature, which in turn affects any computation of feature size, shape and localization. This paper investigates the effect of varying the segmentation algorithm and its controlling parameters by considering a test case: a structured surface for bearing applications, the relevant features being micro-dimples designed for friction reduction. In particular, the mechanisms through which segmentation leads to identification of the dimple boundary and influences dimensional properties, such as dimple diameter and depth, are illustrated. It is shown that, by using different methods and control parameters, a significant range of measurement results can be achieved, which may not necessarily agree. Indications on how to investigate the influence of each specific choice are given; in particular, stability of the algorithms with respect to control parameters is analyzed as a means to investigate ease of calibration and flexibility to adapt to specific, application-dependent characterization requirements. (paper)

  11. Equilibrium current-driven tearing mode in the hydrodynamic regime

    International Nuclear Information System (INIS)

    Cozzani, F.; Mahajan, S.

    1984-12-01

    The effect of the parallel equilibrium current on the linear stability of the drift-tearing mode in the collisional regime is investigated analytically. In the appropriate parameter regime, a new unstable mode, driven by equilibrium current, is found and its relevance to tokamak discharges is discussed

  12. Experimental parameters for quantitative surface analysis by medium energy ion scattering, ch. 1

    International Nuclear Information System (INIS)

    Turkenburg, W.C.; Kersten, H.H.; Colenbrander, B.G.; Jongh, A.P. de; Saris, F.W.

    1976-01-01

    A new UHV chamber for surface and surface layer analysis by collision spectroscopy of backscattered ions at medium energies is described. Experimental parameters like energy, angular and depth resolution, crystal alignment and background pressure are discussed. Formulae based on the use of an electrostatic energy analyser show that the analysis can be quantitative. Effects of beam induced build-up of a hydro-carbon layer, sputter cleaning and creation of radiation damage have been investigated for Cu (110) and Ni (110). Detection sensitivity for Carbon, Oxygen and Sulfur on Cu and Ni has been found to be 0.2, 0.1 and 0.03 of a monolayer respectively

  13. Parameters-related uncertainty in modeling sugar cane yield with an agro-Land Surface Model

    Science.gov (United States)

    Valade, A.; Ciais, P.; Vuichard, N.; Viovy, N.; Ruget, F.; Gabrielle, B.

    2012-12-01

    Agro-Land Surface Models (agro-LSM) have been developed from the coupling of specific crop models and large-scale generic vegetation models. They aim at accounting for the spatial distribution and variability of energy, water and carbon fluxes within soil-vegetation-atmosphere continuum with a particular emphasis on how crop phenology and agricultural management practice influence the turbulent fluxes exchanged with the atmosphere, and the underlying water and carbon pools. A part of the uncertainty in these models is related to the many parameters included in the models' equations. In this study, we quantify the parameter-based uncertainty in the simulation of sugar cane biomass production with the agro-LSM ORCHIDEE-STICS on a multi-regional approach with data from sites in Australia, La Reunion and Brazil. First, the main source of uncertainty for the output variables NPP, GPP, and sensible heat flux (SH) is determined through a screening of the main parameters of the model on a multi-site basis leading to the selection of a subset of most sensitive parameters causing most of the uncertainty. In a second step, a sensitivity analysis is carried out on the parameters selected from the screening analysis at a regional scale. For this, a Monte-Carlo sampling method associated with the calculation of Partial Ranked Correlation Coefficients is used. First, we quantify the sensitivity of the output variables to individual input parameters on a regional scale for two regions of intensive sugar cane cultivation in Australia and Brazil. Then, we quantify the overall uncertainty in the simulation's outputs propagated from the uncertainty in the input parameters. Seven parameters are identified by the screening procedure as driving most of the uncertainty in the agro-LSM ORCHIDEE-STICS model output at all sites. These parameters control photosynthesis (optimal temperature of photosynthesis, optimal carboxylation rate), radiation interception (extinction coefficient), root

  14. Tearing modes in toroidal geometry

    International Nuclear Information System (INIS)

    Connor, J.W.; Cowley, S.C.; Hastie, R.J.; Hender, T.C.; Hood, A.; Martin, T.J.

    1988-01-01

    The separation of the cylindrical tearing mode stability problem into a resistive resonant layer calculation and an external marginal ideal magnetohydrodynamic (MHD) calculation (Δ' calculation) is generalized to axisymmetric toroidal geometry. The general structure of this separation is analyzed and the marginal ideal MHD information (the toroidal generalization of Δ') required to discuss stability is isolated. This can then, in principle, be combined with relevant resonant layer calculations to determine tearing mode growth rates in realistic situations. Two examples are given: the first is an analytic treatment of toroidally coupled (m = 1, n = 1) and (m = 2, n = 1) tearing modes in a large aspect ratio torus; the second, a numerical treatment of the toroidal coupling of three tearing modes through finite pressure effects in a large aspect ratio torus. In addition, the use of a coupling integral approach for determining the stability of coupled tearing modes is discussed. Finally, the possibility of using initial value resistive MHD codes in realistic toroidal geometry to determine the necessary information from the ideal MHD marginal solution is discussed

  15. Airborne-Measured Spatially-Averaged Temperature and Moisture Turbulent Structure Parameters Over a Heterogeneous Surface

    Science.gov (United States)

    Platis, Andreas; Martinez, Daniel; Bange, Jens

    2014-05-01

    Turbulent structure parameters of temperature and humidity can be derived from scintillometer measurements along horizontal paths of several 100 m to several 10 km. These parameters can be very useful to estimate the vertical turbulent heat fluxes at the surface (applying MOST). However, there are many assumptions required by this method which can be checked using in situ data, e.g. 1) Were CT2 and CQ2 correctly derived from the initial CN2 scintillometer data (structure parameter of density fluctuations or refraction index, respectively)? 2) What is the influence of the surround hetereogeneous surface regarding its footprint and the weighted averaging effect of the scintillometer method 3) Does MOST provide the correct turbulent fluxes from scintillometer data. To check these issues, in situ data from low-level flight measurements are well suited, since research aircraft cover horizontal distances in very short time (Taylor's hypothesis of a frozen turbulence structure can be applyed very likely). From airborne-measured time series the spatial series are calculated and then their structure functions that finally provide the structure parameters. The influence of the heterogeneous surface can be controlled by the definition of certain moving-average window sizes. A very useful instrument for this task are UAVs since they can fly very low and maintain altitude very precisely. However, the data base of such unmanned operations is still quite thin. So in this contribution we want to present turbulence data obtained with the Helipod, a turbulence probe hanging below a manned helicopter. The structure parameters of temperature and moisture, CT2 and CQ2, in the lower convective boundary layer were derived from data measured using the Helipod in 2003. The measurements were carried out during the LITFASS03 campaign over a heterogeneous land surface around the boundary-layer field site of the Lindenberg Meteorological Observatory-Richard-Aßmann-Observatory (MOL) of the

  16. A comparison of basal and eye-flush tears for the analysis of cat tear proteins.

    Science.gov (United States)

    Petznick, Andrea; Evans, Margaret D M; Madigan, Michele C; Markoulli, Maria; Garrett, Qian; Sweeney, Deborah F

    2011-02-01

    To identify a rapid and effective tear collection method providing sufficient tear volume and total protein content (TPC) for analysis of individual proteins in cats. Domestic adult short-haired cats (12-37 months; 2.7-6.6 kg) were used in the study. Basal tears without stimulation and eye-flush tears after instillation of saline (10 μl) were collected using microcapillary tubes from animal eyes either unwounded control or wounded with 9-mm central epithelial debridement giving four groups with n = 3. Tear comparisons were based on total time and rate for tear collection, TPC using micro bicinchoninic acid (BCA), tear immunoglobulin A (IgA), total matrix-metalloproteinase (MMP)-9 concentration using sandwich enzyme-linked immunosorbent assay (ELISA) and MMP-9 activity. Eye-flush tears were collected significantly faster than basal tears in wounded eyes with higher rates for tear collection in unwounded control and wounded eyes. TPC was significantly lower in eye-flush tears compared to basal tears. The relative proportion of tear IgA normalized to TPC (% IgA of TPC) was not significantly different between basal and eye-flush tears. In unwounded control eyes, MMP-9 was slightly higher in eye-flush than in basal tears; activity of MMP-9 in both tear types was similar. In wounded eyes, eye-flush tears showed highest MMP-9 levels and activity on Day 1, which subsequently decreased to Day 7. MMP-9 activity in basal tears from wounded eyes did not display changes in expression. Eye-flush tears can be collected rapidly providing sufficient tear volume and TPC. This study also indicates that eye-flush tears may be more suitable than basal tears for the analysis of MMPs following corneal wounding. © 2011 The Authors. Acta Ophthalmologica © 2011 Acta Ophthalmologica Scandinavica Foundation.

  17. Anterior cruciate ligament tear: comparison of MR features between complete and partial tear

    International Nuclear Information System (INIS)

    Song, Ki Young; Lee, Joo Hyuk; Park, Jin Hee; Lee, Yu Jin; Rho, Eun Jin; Kim, Young Hoon; Yi, Jeong Geun; Ahn, Joong Mo

    1997-01-01

    To determine the MRI features which distinguish complete and partial tear of the anterior cruciate ligament(ACL) and to thus improve MRI interpretation. In 80 patients, we analyzed MR findings of direct and indirect signs of ACL tear (complete tear, 61 cases, partial tear, 19 cases) confirmed by arthroscopy or surgery, and compared the relative incidence of each sign in cases of complete and partial tear. Direct and indirect signs were found in 61 (100%) and 60 cases (98.4%), respectively, in complete tears, but in 16 (84.2%) and 15 cases (78.9%), respectively, in partial tears. Poor visualization, discontinuity and hyperintensity were seen in all complete tears but in only nine cases (47.4%) of partial tear. A wavy or abnormal contour was seen in 53 cases (86.9%) of complete tear and 14 (73.7%) of partial tear. A wavy contour without other direct signs was seen in only five cases (26.3%) of partial tear. Three cases (15.8%) of partial tear showed normal MR finding. Indirect signs, i.e. abnormal ACL angle, abnormal ACL-Blumensaat line angle, abnormal posterior cruciate ligament (PCL) line, abnormal PCL angle, PCL buckling, anterior displacement of tibia, posterior displacement of lateral meniscus, bone bruise, Segond fracture, tear of collateral ligaments, PCL, and tear of meniscus were commoner in complete than in partial tears. Two cases of O'Donoghue's triad and two of popliteus injury were seen only in complete tears. Direct and indirect signs of ACL tear were more commonly noted in complete than in partial tears. The latter showed MR features varying from normal to almost complete tear. We suggest that a wavy contour without other direct signs is indicative of a partial tear, and that O'Donoghue's triad and popliteus muscle injury are indirect signs of a complete tear

  18. Influence of Drilling Parameters on Torque during Drilling of GFRP Composites Using Response Surface Methodology

    Science.gov (United States)

    Mohan, N. S.; Kulkarni, S. M.

    2018-01-01

    Polymer based composites have marked their valuable presence in the area of aerospace, defense and automotive industry. Components made of composite, are assembled to main structure by fastener, which require accurate, precise high quality holes to be drilled. Drilling the hole in composite with accuracy require control over various processes parameters viz., speed, feed, drill bit size and thickens of specimen. TRIAC VMC machining center is used to drill the hole and to relate the cutting and machining parameters on the torque. MINITAB 14 software is used to analyze the collected data. As a function of cutting and specimen parameters this method could be useful for predicting torque parameters. The purpose of this work is to investigate the effect of drilling parameters to get low torque value. Results show that thickness of specimen and drill bit size are significant parameters influencing the torque and spindle speed and feed rate have least influence and overlaid plot indicates a feasible and low region of torque is observed for medium to large sized drill bits for the range of spindle speed selected. Response surface contour plots indicate the sensitivity of the drill size and specimen thickness to the torque.

  19. Investigation of the physical parameters of duplex stainless steel (DSS surface integrity after turning

    Directory of Open Access Journals (Sweden)

    G. Krolczyk

    2015-01-01

    Full Text Available The article presents the influence of machining parameters on the microhardness of surface integrity (SI after turning by means of a coated sintered carbide wedge with a coating with ceramic intermediate layer. The investigation comprised the influence of cutting speed on the SI microhardness in dry machining. The material under investigation was duplex stainless steel with two-phase ferritic-austenitic structure. The results obtained allow for conclusions concerning the exploitation features of processed machine parts.

  20. Measurement of hydrogeologic parameters of Indian volcanic rocks by sub-surface hydronuclear techniques

    International Nuclear Information System (INIS)

    Bardhan, M.

    1977-01-01

    Sub-surface hydronuclear techniques namely neutron-neutron, gamma-gamma and tracer dilution logging and single and double well tracer methods were adopted to investigate the hitherto inadequately studied hydrophysical properties of the Deccan lava flows which constitute the principal Indian volcanic suit of rocks. The hydrogeologic parameters measured in the field pertain to hydrostratigraphy, hydrostorage properties and geohydraulic characteristics of these layered hard formations. Results of the studies are presented and discussed briefly. (author)

  1. SENSITIVITY OF BODY SWAY PARAMETERS DURING QUIET STANDING TO MANIPULATION OF SUPPORT SURFACE SIZE

    Directory of Open Access Journals (Sweden)

    Sarabon Nejc

    2010-09-01

    Full Text Available The centre of pressure (COP movement during stance maintenance on a stable surface is commonly used to describe and evaluate static balance. The aim of our study was to test sensitivity of individual COP parameters to different stance positions which were used to address size specific changes in the support surface. Twenty-nine subjects participated in the study. They carried out three 60-second repetitions of each of the five balance tasks (parallel stance, semi-tandem stance, tandem stance, contra-tandem stance, single leg stance. Using the force plate, the monitored parameters included the total COP distance, the distance covered in antero-posterior and medio-lateral directions, the maximum oscillation amplitude in antero-posterior and medio-lateral directions, the total frequency of oscillation, as well as the frequency of oscillation in antero-posterior and medio-lateral directions. The parameters which describe the total COP distance were the most sensitive to changes in the balance task, whereas the frequency of oscillation proved to be sensitive to a slightly lesser extent. Reductions in the support surface size in each of the directions resulted in proportional changes of antero-posterior and medio- lateral directions. The frequency of oscillation did not increase evenly with the increase in the level of difficulty of the balance task, but reached a certain value, above which it did not increase. Our study revealed the monitored parameters of the COP to be sensitive to the support surface size manipulations. The results of the study provide an important source for clinical and research use of the body sway measurements.

  2. Effect of lipid-based dry eye supplements on the tear film in wearers of eye cosmetics.

    Science.gov (United States)

    Wang, Michael T M; Cho, Irene Sung Hee; Jung, Soo Hee; Craig, Jennifer P

    2017-08-01

    To compare the effects on tear film parameters and contamination in cosmetic eyeliner wearers, after single application of two lipid-based dry eye treatments: a lipid-containing lubricant eye drop and a phospholipid liposomal spray. Fifty participants were enrolled in a prospective, randomised, paired-eye, investigator-masked trial. Pencil eyeliner (Body Shop ® Crayon Eye Definer) was applied to the upper eyelid periocular skin of both eyes, anterior to the lash line. Baseline tear film quality was assessed fifteen minutes after eyeliner application. A lubricant drop (Systane ® Balance) was then applied to one eye (randomised), and liposomal spray (Tears Again ® ) to the contralateral eye. Tear film contamination, lipid layer grade, non-invasive tear film break-up time and tear evaporation rate were evaluated fifteen minutes post-treatment and compared to pre-treatment values. Pre-treatment measurements did not differ between eyes assigned to lubricant drop and liposomal spray. Tear film contamination was observed in a greater proportion of eyes following both treatments (both p0.05). Changes in tear film parameters did not differ between treatments (all p>0.05). Both the lipid-containing lubricant eye drop and phospholipid liposomal spray result in clinically apparent tear film contamination in eyeliner cosmetic wearers. Although both treatments effected an increase in lipid layer thickness, neither displayed clinical efficacy in improving tear film stability. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  3. Estimation of real-time runway surface contamination using flight data recorder parameters

    Science.gov (United States)

    Curry, Donovan

    Within this research effort, the development of an analytic process for friction coefficient estimation is presented. Under static equilibrium, the sum of forces and moments acting on the aircraft, in the aircraft body coordinate system, while on the ground at any instant is equal to zero. Under this premise the longitudinal, lateral and normal forces due to landing are calculated along with the individual deceleration components existent when an aircraft comes to a rest during ground roll. In order to validate this hypothesis a six degree of freedom aircraft model had to be created and landing tests had to be simulated on different surfaces. The simulated aircraft model includes a high fidelity aerodynamic model, thrust model, landing gear model, friction model and antiskid model. Three main surfaces were defined in the friction model; dry, wet and snow/ice. Only the parameters recorded by an FDR are used directly from the aircraft model all others are estimated or known a priori. The estimation of unknown parameters is also presented in the research effort. With all needed parameters a comparison and validation with simulated and estimated data, under different runway conditions, is performed. Finally, this report presents results of a sensitivity analysis in order to provide a measure of reliability of the analytic estimation process. Linear and non-linear sensitivity analysis has been performed in order to quantify the level of uncertainty implicit in modeling estimated parameters and how they can affect the calculation of the instantaneous coefficient of friction. Using the approach of force and moment equilibrium about the CG at landing to reconstruct the instantaneous coefficient of friction appears to be a reasonably accurate estimate when compared to the simulated friction coefficient. This is also true when the FDR and estimated parameters are introduced to white noise and when crosswind is introduced to the simulation. After the linear analysis the

  4. The Influence Study of Ultrasonic honing parameters to workpiece surface temperature

    Directory of Open Access Journals (Sweden)

    Zhang Xiaoqiang

    2016-01-01

    Full Text Available Ultrasonic vibration honing(UVH, a machine technology, has a lot of advantages. Lower grinding temperature is a significant character and is beneficial for both processing and workpiece surface. But the high temperature caused by big honing pressure becomes the main factor to produce workpiece heat damage in grinding zone. In various honing parameter combinations, the showing effect is different. Based on the thermodynamics classical theory, established the heat transfer equation for grinding zone, simplified the model and obtained the two-dimenssion temperature field expression for workpiece, then simulated the temperature changing trend in a variety of conditions. It is shown that themain temp is in a range of 700K to 1200K. In addition, the variation is huge for every parameter. The study provides a theoretical basis for deeply seeking reasonable machining parameter and obtaining better workpiece quality.

  5. Procedure to approximately estimate the uncertainty of material ratio parameters due to inhomogeneity of surface roughness

    International Nuclear Information System (INIS)

    Hüser, Dorothee; Thomsen-Schmidt, Peter; Hüser, Jonathan; Rief, Sebastian; Seewig, Jörg

    2016-01-01

    Roughness parameters that characterize contacting surfaces with regard to friction and wear are commonly stated without uncertainties, or with an uncertainty only taking into account a very limited amount of aspects such as repeatability of reproducibility (homogeneity) of the specimen. This makes it difficult to discriminate between different values of single roughness parameters. Therefore uncertainty assessment methods are required that take all relevant aspects into account. In the literature this is rarely performed and examples specific for parameters used in friction and wear are not yet given. We propose a procedure to derive the uncertainty from a single profile employing a statistical method that is based on the statistical moments of the amplitude distribution and the autocorrelation length of the profile. To show the possibilities and the limitations of this method we compare the uncertainty derived from a single profile with that derived from a high statistics experiment. (paper)

  6. Glycan involvement in the adhesion of Pseudomonas aeruginosa to tears.

    Science.gov (United States)

    Kautto, Liisa; Nguyen-Khuong, Terry; Everest-Dass, Arun; Leong, Andrea; Zhao, Zhenjun; Willcox, Mark D P; Packer, Nicolle H; Peterson, Robyn

    2016-04-01

    The human eye is constantly bathed by tears, which protect the ocular surface via a variety of mechanisms. The O-linked glycans of tear mucins have long been considered to play a role in binding to pathogens and facilitating their removal in the tear flow. Other conjugated glycans in tears could similarly contribute to pathogen binding and removal but have received less attention. In the work presented here we assessed the contribution of glycan moieties, in particular the protein attached N-glycans, presented by the broad complement of tear proteins to the adhesion of the opportunistic pathogen Pseudomonas aeruginosa, a leading cause of microbial keratitis and ulceration of the cornea. Our adhesion assay involved immobilising the macromolecular components of tears into the wells of a polyvinyl difluoride (PVDF) microtitre filter plate and probing the binding of fluorescently labelled bacteria. Three P. aeruginosa strains were studied: a cytotoxic strain (6206) and an invasive strain (6294) from eye infections, and an invasive strain (320) from a urinary tract infection (UTI). The ocular isolates adhered two to three times more to human tears than to human saliva or porcine gastric mucin, suggesting ocular niche-specific adaptation. Support for the role of the N-glycans carried by human tear proteins in the binding and removal of P. aeruginosa from the eye was shown by: 1) pre-incubation of the bacteria with free component sugars, galactose, mannose, fucose and sialyl lactose (or combination thereof) inhibiting adhesion of all the P. aeruginosa strains to the immobilised tear proteins, with the greatest inhibition of binding of the ocular cytotoxic 6206 and least for the invasive 6294 strain; 2) pre-incubation of the bacteria with N-glycans released from the commercially available human milk lactoferrin, an abundant protein that carries N-linked glycans in tears, inhibiting the adhesion to tears of the ocular bacteria by up to 70%, which was significantly more

  7. The effect of drilling parameters for surface roughness in drilling of AA7075 alloy

    Directory of Open Access Journals (Sweden)

    Yaşar Nafiz

    2017-01-01

    Full Text Available AA7075 aluminum alloy has been very popular significantly interest in the production of structural components in automotive and aviation applications due to its high strength, low density, good plasticity and better machinability comparable to many metals. Particularly, final products must have uniformly high quality to ensure essential safety standards in the aircraft industry. The optimization of hole quality which can variable according to tool geometry and drilling parameters is important in spite of high machinability rate of AA7075 alloy. In this study, the effects of drilling parameters on average surface roughness (Ra has been investigated in drilling of AA7075 with tungsten carbide drills. Machining experiments were performed with three different drill point angles and three different levels of cutting parameters (feed rate, cutting speed. The effects of drilling parameters on thrust force has been determined with ANOVA in %95 confidence level. Feed rate was determined as the most important factor on Ra according to ANOVA results. Moreover, it was shown that increasing feed rate leads to increase of Ra while increasing drill point angle leads to decrease of Ra. The optimum surface roughness was obtained with point angle of 130°, cutting speed of 40 m/min and feed rate of 0.1 mm/rev, thereby the validity of optimization was confirmed with Taguchi method.

  8. Effects of Spatial Sampling Interval on Roughness Parameters and Microwave Backscatter over Agricultural Soil Surfaces

    Directory of Open Access Journals (Sweden)

    Matías Ernesto Barber

    2016-06-01

    Full Text Available The spatial sampling interval, as related to the ability to digitize a soil profile with a certain number of features per unit length, depends on the profiling technique itself. From a variety of profiling techniques, roughness parameters are estimated at different sampling intervals. Since soil profiles have continuous spectral components, it is clear that roughness parameters are influenced by the sampling interval of the measurement device employed. In this work, we contributed to answer which sampling interval the profiles needed to be measured at to accurately account for the microwave response of agricultural surfaces. For this purpose, a 2-D laser profiler was built and used to measure surface soil roughness at field scale over agricultural sites in Argentina. Sampling intervals ranged from large (50 mm to small ones (1 mm, with several intermediate values. Large- and intermediate-sampling-interval profiles were synthetically derived from nominal, 1 mm ones. With these data, the effect of sampling-interval-dependent roughness parameters on backscatter response was assessed using the theoretical backscatter model IEM2M. Simulations demonstrated that variations of roughness parameters depended on the working wavelength and was less important at L-band than at C- or X-band. In any case, an underestimation of the backscattering coefficient of about 1-4 dB was observed at larger sampling intervals. As a general rule a sampling interval of 15 mm can be recommended for L-band and 5 mm for C-band.

  9. Assisted crack tip flipping under Mode I thin sheet tearing

    DEFF Research Database (Denmark)

    Felter, Christian Lotz; Nielsen, Kim Lau

    2017-01-01

    Crack tip flipping, where the fracture surface alternates from side to side in roughly 45° shear bands, seems to be an overlooked propagation mode in Mode I thin sheet tearing. In fact, observations of crack tip flipping is rarely found in the literature. Unlike the already established modes...

  10. Crack Tip Flipping Under Mode I/III Tearing

    DEFF Research Database (Denmark)

    Felter, Christian Lotz; Specht Jensen, Lasse; Nielsen, Kim Lau

    Crack tip flipping, where the fracture surface alternates from side to side in 45° shear bands, seems to be an overlooked propagation mode in Mode I sheet tearing often disregarded as  “transitional” or tied to randomness in the material. In fact, such observations rarely make it to the literature...

  11. Mode coupling trigger of neoclassical magnetohydrodynamic tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Gianakon, T.A.; Hegna, C.C.; Callen, J.D.

    1997-05-01

    Numerical studies of the nonlinear evolution of coupled magnetohydrodynamic - type tearing modes in three-dimensional toroidal geometry with neoclassical effects are presented. The inclusion of neoclassical physics introduces an additional free-energy source for the nonlinear formation of magnetic islands through the effects of a bootstrap current in Ohm's law. The neoclassical tearing mode is demonstrated to be destabilized in plasmas which are otherwise Δ' stable, albeit once a threshold island width is exceeded. A possible mechanism for exceeding or eliminating this threshold condition is demonstrated based on mode coupling due to toroidicity with a pre-existing instability at the q = 1 surface

  12. Postanaesthetic tear production and ocular irritation in cats.

    Science.gov (United States)

    Peche, N; Köstlin, R; Reese, S; Pieper, K

    2015-01-01

    General anaesthesia significantly reduces tear production and normal values are not immediately re-established on ending anaesthesia. Therefore, adequate protection of the cornea has to be assured during the perianaesthetic period. There are various methods available, including taping of the eyelids and the application of eye ointments, gels and drops. In human medicine studies, different formulations were found to induce signs of ocular irritation. The aim of the present study was to determine tear production in cats after general anaesthesia, and to identify possible causes of irritation. Tear production was determined in 41 cats after general anaesthesia and eyes were examined for signs of irritation. Two different anaesthetic protocols were used. To protect the cornea, an ointment and gel were applied to the right and left eyes, respectively. Postoperatively, tear production was significantly reduced for 6 hours and 18 hours in the right and left eyes, respectively. Two hours after anaesthesia, blepharospasm of the right eye was observed in 92.7% (n = 38) of the cats. In contrast, the left eye was always held open. This study demonstrated that tear production in cats is significantly decreased both during and after anaesthesia. The degree of reduction was independent of the anaesthetic protocol. Both the eye ointment and gel proved effective in protecting the corneal surface. However, eye gel use is recommended because the eye ointment consistently caused an irritation comparable to the foreign-body sensation reported in humans.

  13. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Science.gov (United States)

    Zuluaga-Ramírez, Pablo; Frövel, Malte; Belenguer, Tomás; Salazar, Félix

    2015-01-01

    This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL) and realistic variable amplitude loads (VAL), representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications. PMID:28793655

  14. External Thermal Insulation Composite Systems: Critical Parameters for Surface Hygrothermal Behaviour

    Directory of Open Access Journals (Sweden)

    Eva Barreira

    2014-01-01

    Full Text Available External Thermal Insulation Composite Systems (ETICS are often used in Europe. Despite its thermal advantages, low cost, and ease of application, this system has serious problems of biological growth causing the cladding defacement. Recent studies pointed that biological growth is due to high values of surface moisture content, which mostly results from the combined effect of exterior surface condensation, wind-driven rain, and drying process. Based on numerical simulation, this paper points the most critical parameters involved in hygrothermal behaviour of ETICS, considering the influence of thermal and hygric properties of the external rendering, the effect of the characteristics of the façade, and the consequences of the exterior and interior climate on exterior surface condensation, wind-driven rain, and drying process. The model used was previously validated by comparison with the results of an “in situ” campaign. The results of the sensitivity analyses show that relative humidity and temperature of the exterior air, atmospheric radiation, and emissivity of the exterior rendering are the parameters that most influence exterior surface condensation. Wind-driven rain depends mostly on horizontal rain, building’s height, wind velocity, and orientation. The drying capacity is influenced by short-wave absorbance, incident solar radiation, and orientation.

  15. Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

    Directory of Open Access Journals (Sweden)

    Pablo Zuluaga-Ramírez

    2015-11-01

    Full Text Available This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL and realistic variable amplitude loads (VAL, representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications.

  16. Optimal Machining Parameters for Achieving the Desired Surface Roughness in Turning of Steel

    Directory of Open Access Journals (Sweden)

    LB Abhang

    2012-06-01

    Full Text Available Due to the widespread use of highly automated machine tools in the metal cutting industry, manufacturing requires highly reliable models and methods for the prediction of output performance in the machining process. The prediction of optimal manufacturing conditions for good surface finish and dimensional accuracy plays a very important role in process planning. In the steel turning process the tool geometry and cutting conditions determine the time and cost of production which ultimately affect the quality of the final product. In the present work, experimental investigations have been conducted to determine the effect of the tool geometry (effective tool nose radius and metal cutting conditions (cutting speed, feed rate and depth of cut on surface finish during the turning of EN-31 steel. First and second order mathematical models are developed in terms of machining parameters by using the response surface methodology on the basis of the experimental results. The surface roughness prediction model has been optimized to obtain the surface roughness values by using LINGO solver programs. LINGO is a mathematical modeling language which is used in linear and nonlinear optimization to formulate large problems concisely, solve them, and analyze the solution in engineering sciences, operation research etc. The LINGO solver program is global optimization software. It gives minimum values of surface roughness and their respective optimal conditions.

  17. Coupled Kelvin-Helmholtz and Tearing Mode Instabilities at the Mercury's Magnetopause

    Science.gov (United States)

    Ivanovski, S. L.; Milillo, A.; Kartalev, M.; Massetti, S.

    2018-05-01

    A MHD approach for numerical simulations of coupled Kelvin-Helmholtz and tearing mode instabilities has been applied to Mercury’s magnetopause and used to perform a physical parameters study constrained by the MESSENGER data.

  18. Influence of the electromagnetic parameters on the surface wave attenuation in thin absorbing layers

    Science.gov (United States)

    Li, Yinrui; Li, Dongmeng; Wang, Xian; Nie, Yan; Gong, Rongzhou

    2018-05-01

    This paper describes the relationships between the surface wave attenuation properties and the electromagnetic parameters of radar absorbing materials (RAMs). In order to conveniently obtain the attenuation constant of TM surface waves over a wide frequency range, the simplified dispersion equations in thin absorbing materials were firstly deduced. The validity of the proposed method was proved by comparing with the classical dispersion equations. Subsequently, the attenuation constants were calculated separately for the absorbing layers with hypothetical relative permittivity and permeability. It is found that the surface wave attenuation properties can be strongly tuned by the permeability of RAM. Meanwhile, the permittivity should be appropriate so as to maintain high cutoff frequency. The present work provides specific methods and designs to improve the attenuation performances of radar absorbing materials.

  19. Estimation of Key Parameters of the Coupled Energy and Water Model by Assimilating Land Surface Data

    Science.gov (United States)

    Abdolghafoorian, A.; Farhadi, L.

    2017-12-01

    Accurate estimation of land surface heat and moisture fluxes, as well as root zone soil moisture, is crucial in various hydrological, meteorological, and agricultural applications. Field measurements of these fluxes are costly and cannot be readily scaled to large areas relevant to weather and climate studies. Therefore, there is a need for techniques to make quantitative estimates of heat and moisture fluxes using land surface state observations that are widely available from remote sensing across a range of scale. In this work, we applies the variational data assimilation approach to estimate land surface fluxes and soil moisture profile from the implicit information contained Land Surface Temperature (LST) and Soil Moisture (SM) (hereafter the VDA model). The VDA model is focused on the estimation of three key parameters: 1- neutral bulk heat transfer coefficient (CHN), 2- evaporative fraction from soil and canopy (EF), and 3- saturated hydraulic conductivity (Ksat). CHN and EF regulate the partitioning of available energy between sensible and latent heat fluxes. Ksat is one of the main parameters used in determining infiltration, runoff, groundwater recharge, and in simulating hydrological processes. In this study, a system of coupled parsimonious energy and water model will constrain the estimation of three unknown parameters in the VDA model. The profile of SM (LST) at multiple depths is estimated using moisture diffusion (heat diffusion) equation. In this study, the uncertainties of retrieved unknown parameters and fluxes are estimated from the inverse of Hesian matrix of cost function which is computed using the Lagrangian methodology. Analysis of uncertainty provides valuable information about the accuracy of estimated parameters and their correlation and guide the formulation of a well-posed estimation problem. The results of proposed algorithm are validated with a series of experiments using a synthetic data set generated by the simultaneous heat and

  20. High-resolution magnetic resonance imaging of rotator cuff tears using a microscopy coil. Noninvasive detection without intraarticular contrast material

    International Nuclear Information System (INIS)

    Hitachi, Shin; Takase, Kei; Higano, Shuichi; Takahashi, Shoki; Tanaka, Minoru; Tojo, Yuichi; Tabata, Shiro; Majima, Kazuhiro

    2011-01-01

    The aim of this study was to evaluate the feasibility of high-resolution magnetic resonance imaging (MRI) using a microscopy coil for the diagnosis of rotator cuff tears by comparing the method to conventional MRI and MRI arthrography. A total of 68 shoulders were prospectively studied using a 1.5-T MRI unit. Conventional MRI scans were obtained with a surface coil and high-resolution MRI scans with a microscopy coil. MRI arthrography was performed in 28 shoulders using a surface coil. MRI evaluation of tears of rotator cuff tendons was compared with arthroscopic findings and surgical results. The surgery revealed 40 full-thickness tears, 13 partial-thickness tears, and 15 intact cuffs. In all, 35 (88%) full-thickness tears were correctly diagnosed on conventional MRI and 40 (100%) on high-resolution MRI. MR arthrography delineated 11 of 12 (92%) full-thickness tears. Altogether, 5 (38%) of the partial-thickness tears were detected on conventional MRI, and 12 (92%) were clearly demonstrated on high-resolution MRI. MRI arthrography depicted three (60%) of five partial-thickness tears. High-resolution MRI showed higher sensitivity than conventional MRI (P<0.05) and had values equivalent to those of MRI arthrography for diagnosing partial-thickness tears. High-resolution MRI with a microscopy coil is a feasible, noninvasive technique for diagnosing rotator cuff tears. (author)

  1. What emotional tears convey : Tearful individuals are seen as warmer, but also as less competent

    NARCIS (Netherlands)

    van de Ven, Niels; Meijs, Maartje; Vingerhoets, A.J.J.M.

    Earlier research found that the mere sight of tears promotes the willingness to provide support to the person shedding the tears. Other research, however, found that deliberate responses towards tearful persons could be more negative as well. We think this is because tears have ambivalent effects on

  2. Acute Medial Plantar Fascia Tear.

    Science.gov (United States)

    Pascoe, Stephanie C; Mazzola, Timothy J

    2016-06-01

    A 32-year-old man who participated in competitive soccer came to physical therapy via direct access for a chief complaint of plantar foot pain. The clinical examination findings and mechanism of injury raised a concern for a plantar fascia tear, so the patient was referred to the physician and magnetic resonance imaging was obtained. The magnetic resonance image confirmed a high-grade, partial-thickness, proximal plantar fascia tear with localized edema at the location of the medial band. J Orthop Sports Phys Ther 2016;46(6):495. doi:10.2519/jospt.2016.0409.

  3. Optimization of operating parameters in polysilicon chemical vapor deposition reactor with response surface methodology

    Science.gov (United States)

    An, Li-sha; Liu, Chun-jiao; Liu, Ying-wen

    2018-05-01

    In the polysilicon chemical vapor deposition reactor, the operating parameters are complex to affect the polysilicon's output. Therefore, it is very important to address the coupling problem of multiple parameters and solve the optimization in a computationally efficient manner. Here, we adopted Response Surface Methodology (RSM) to analyze the complex coupling effects of different operating parameters on silicon deposition rate (R) and further achieve effective optimization of the silicon CVD system. Based on finite numerical experiments, an accurate RSM regression model is obtained and applied to predict the R with different operating parameters, including temperature (T), pressure (P), inlet velocity (V), and inlet mole fraction of H2 (M). The analysis of variance is conducted to describe the rationality of regression model and examine the statistical significance of each factor. Consequently, the optimum combination of operating parameters for the silicon CVD reactor is: T = 1400 K, P = 3.82 atm, V = 3.41 m/s, M = 0.91. The validation tests and optimum solution show that the results are in good agreement with those from CFD model and the deviations of the predicted values are less than 4.19%. This work provides a theoretical guidance to operate the polysilicon CVD process.

  4. Is the Near-Earth Current Sheet Prior to Reconnection Unstable to Tearing Mode?

    International Nuclear Information System (INIS)

    Xin-Hua, Wei; Jin-Bin, Cao; Guo-Cheng, Zhou; Hui-Shan, Fu

    2010-01-01

    The tearing mode instability plays a key role in the triggering process of reconnection. The triggering collisionless tearing mode instability has been theoretically and numerically analyzed by many researchers. However, due to the difficulty in obtaining the observational wave number, it is still unknown whether the tearing mode instability can be excited in an actual plasma sheet prior to reconnection onset. Using the data from four Cluster satellites prior to a magnetospheric reconnection event on 13 September 2002, we utilized the wave telescope technique to obtain the wave number which corresponds to the peak of power spectral density. The wavelength is about 18R E and is consistent with previous theoretic and numerical results. After substituting the wave vector and other necessary parameters of the observed current sheet into the triggering condition of tearing mode instability, we find that the near-Earth current sheet prior to reconnection is unstable to tearing mode. (geophysics, astronomy, and astrophysics)

  5. Can the optimum artificial tear treatment for dry eye disease be predicted from presenting signs and symptoms?

    Science.gov (United States)

    Essa, Laika; Laughton, Deborah; Wolffsohn, James S

    2018-02-01

    To assess dry eye treatment with four preservative-free dry eye artificial tear treatments to facilitate evidence-based prescribing. A randomised, single masked crossover trial of Clinitas Soothe, Hyabak, Tears Again and TheraTears artificial tears was conducted on 50 symptomatic dry eye patients, aged 60.8±14.2years. At baseline and after trialling each treatment for 4 weeks, signs and symptoms were assessed using the Ocular Surface Disease Index (OSDI), non-invasive tear break-up time, fluorescein tear break-up time, tear meniscus height (TMH), Phenol Red test, lid-parallel conjunctival folds (LIPCOF), ocular surface staining, and lipid layer grading and osmolarity (baseline visit only). OSDI (p=0.002), LIPCOF (p=0.014) and conjunctival staining (pdry eye treatment on ocular symptoms and signs was similar. Clinitas Soothe and Hyabak were preferred by 34%/30% of participants, but only subjective comparison with the other drops influenced this choice. TheraTears was preferred (by 24%) by those with a lower baseline tear volume (p=0.01) and Tears Again (by 12%) by those with a thinner baseline lipid layer (p=0.04). The treatment that afforded the greatest improvement in clinical signs did not consistently match each individual's preferred treatment. If prescribed to a general dry eye population, the artificial tears performed similarly, improving symptoms and conjunctival signs. However, osmolarity balanced artificial tears were the preferred treatment in individuals with low baseline tear volume and lipisomal spray for individuals with a baseline lipid layer deficiency. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  6. Simulation of Nanowires on Metal Vicinal Surfaces: Effect of Growth Parameters and Energetic Barriers

    Science.gov (United States)

    Hamouda, Ajmi B. H.; Blel, Sonia; Einstein, T. L.

    2012-02-01

    Growing one-dimensional metal structures is an important task in the investigation of the electronic and magnetic properties of new devices. We used kinetic Monte-Carlo (kMC) method to simulate the formation of nanowires of several metallic and non-metallic adatoms on Cu and Pt vicinal surfaces. We found that mono-atomic chains form on step-edges due to energetic barriers (the so-called Ehrlich-shwoebel and exchange barriers) on step-edge. Creation of perfect wires is found to depend on growth parameters and binding energies. We measure the filling ratio of nanowires for different chemical species in a wide range of temperature and flux. Perfect wires were obtained at lower deposition rate for all tested adatoms, however we notice different temperature ranges. Our results were compared with experimental ones [Gambardella et al., Surf. Sci.449, 93-103 (2000), PRB 61, 2254-2262, (2000)]. We review the role of impurities in nanostructuring of surfaces [Hamouda et al., Phys. Rev. B 83, 035423, (2011)] and discuss the effect of their energetic barriers on the obtained quality of nanowires. Our work provides experimentalists with optimum growth parameters for the creation of a uniform distribution of wires on surfaces.

  7. Quantification of the lift height for magnetic force microscopy using 3D surface parameters

    International Nuclear Information System (INIS)

    Nenadovic, M.; Strbac, S.; Rakocevic, Z.

    2010-01-01

    In this work, the quantitative conditions for the lift height for imaging of the magnetic field using magnetic force microscopy (MFM) were optimized. A thin cobalt film deposited on a monocrystalline silicon (1 0 0) substrate with a thickness of 55 nm and a thin nickel film deposited on a glass with a thickness of 600 nm were used as samples. The topography of the surface was acquired by tapping mode atomic force microscopy (AFM), while MFM imaging was performed in the lift mode for various lift heights. It was determined that the sensitivity of the measurements was about 10% higher for images obtained at a scan angle of 90 o compared to a scan angle of 0 deg. Therefore, the three-dimensional surface texture parameters, i.e., average roughness, skewness, kurtosis and the bearing ratio, were determined in dependence on the lift height for a scan angle of 90 deg. The results of the analyses of the surface parameters showed that the influence of the substrate and its texture on the magnetic force image could be neglected for lift heights above 40 nm and that the upper lift height limit is 100 nm. It was determined that the optimal values of the lift heights were in the range from 60 to 80 nm, depending on the nature of the sample and on the type of the tip used.

  8. Spectral-domain optical coherence tomography study on dynamic changes of human tears after instillation of artificial tears.

    Science.gov (United States)

    Napoli, Pietro Emanuele; Satta, Giovanni Maria; Coronella, Franco; Fossarello, Maurizio

    2014-07-01

    To analyze in vivo the dynamic changes induced by different artificial tears (ATs) in the precorneal tear film (PCTF) and lower tear meniscus (LTM) by using spectral-domain (SD) anterior segment optical coherence tomography (OCT). We prospectively examined 42 normal human eyes by using SD-OCT imaging. On the day before OCT imaging, all enrolled subjects were evaluated for abnormalities of ocular surface. All tear film images were obtained before and after instillation of three different types of ATs (mucomimetic, lipid-based, and saline) in five serial scans: immediately (within 30 seconds), at the first, fifth, 10th, and 20th minute. Subjects received a drop of 35 μL in one randomly selected eye. All examinations were conducted in the same conditions of temperature, brightness, humidity, and time of day. Changes in the morphological pattern of both LTM and PCTF were associated with the type of artificial tear instilled on the ocular surface. Similarly, the radius of curvature (rc), the height (h), and the depth (d) showed dynamic variations depending on treatment. Although by the 20th minute, both h and d returned to baseline values in all groups, a significant difference in rc (compared with baseline) was detected for mucomimetic ATs (P = 0.04) and lipid ATs (P = 0.02). Spectral-domain OCT imaging has preliminarily proved to be a noninvasive tool to evaluate, in real time, the different changes induced by ATs instillation. An important stride in understanding the clinical response to various tear substitutes can be achieved by this objective and quantitative approach. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  9. Standard sonography and arthrosonography in the study of rotator cuff tears

    International Nuclear Information System (INIS)

    El-Dalati, Ghassan; Martone, Enrico; Caffarri, Sabrina; Fusaro, Michele; Pozzi Mucelli, Roberto; Castellarin, Gianluca; Ricci, Matteo; Vecchini, Eugenio

    2005-01-01

    Purpose. The aim of this study was to evaluate the sensitivity of ultrasonography, integrating standard ultrasound and arthrosonography after injecting a saline solution into the glenohumeral cavity in cases of suspected rotator cuff tears. Materials and methods. We respectively examinated 40 patients awaiting shoulder arthroscopy for suspected or diagnosed tears of the rotator cuff. A radiologist, unaware of the pre-operative diagnosis, performed an ultrasound scan on all the patients before and after the injection of saline solution into the glenohumeral cavity. The parameters considered were presence or absence of a rotator cuff injury; type of injury according to Snyder and its extent along the longitudinal and transverse planes; presence or absence of effusion into the articular cavity; subacromial/subdeltoid bursal distension. All the patients underwent arthroscopy either the same day of the day after the ultrasound examination. Results. Standard sonography showed 26 complete rotator cuff tears (type C according to Snyder), 2 partial tears (type B according to Snyder) and 12 intact rotator cuffs. Arthrosonography detected 31 complete rotator cuff tears (type C according to Snyder), 1 partial tear (type B according to Snyder) and 8 intact rotator cuffs. Arthroscopy identified 32 complete rotator cuff tears (type C according to Snyder), 1 partial tear (type B according to Snyder) and 8 intact rotator cuffs. Analysis of the results shows that, taking arthroscopy as the gold standard, the sensitivity of normal sonography is 81.2%, whereas that of arthosonography is 96.8% (p [it

  10. A Special Tear Pattern of Anterior Horn of the Lateral Meniscus: Macerated Tear.

    Science.gov (United States)

    Zheng, Jiapeng; Zhai, Wenliang; Li, Qiang; Jia, Qianxin; Lin, Dasheng

    2017-01-01

    We describe a special, interesting phenomenon found in the anterior horn of the lateral meniscus (AHLM): most tear patterns in the AHLM are distinctive, with loose fibers in injured region and circumferential fiber bundles were separated. We name it as macerated tear. The goal of this study was to bring forward a new type of meniscal tear in the AHLM and investigate its clinical value. AHLM tears underwent arthroscopic surgery from January 2012 to December 2014 were included. Data regarding the integrity of AHLM were prospectively recorded in a data registry. Tear morphology and treatment received were subsequently extracted by 2 independent reviewers from operative notes and arthroscopic surgical photos. A total of 60 AHLM tears in 60 patients (mean age 27.1 years) were grouped into horizontal tears (n = 15, 25%), vertical tears (n = 14, 23%), complex tears (n = 6, 10%), and macerated tears (n = 25, 42%). There were 6 patients with AHLM cysts in macerated tear group and one patient in vertical tear group. 60 patients were performed arthroscopic meniscus repairs and were followed-up with averaged 18.7 months. Each group had significant postoperative improvement in Lysholm and IKDC scores (p 0.05). This study demonstrated that the macerated tear is common in the tear pattern of AHLM. However, feasibility of the treatment of this type of meniscal tear, especially the meniscus repairs still requires further study.

  11. Kinetic theory of tearing instabilities

    International Nuclear Information System (INIS)

    Drake, J.F.; Lee, Y.C.

    1977-01-01

    The transition of the tearing instability from the collisional to the collisionless regime is investigated kinetically using a Fokker--Planck collision operator to represent electron-ion collisions. As a function of the collisionality of the plasma, the tearing instability falls into three regions, which are referred to as collisionless, semi-collisional, and collisional. The width Δ of the singular layer around kxB 0 =0 is limited by electron thermal motion along B 0 in the collisional and semi-collisional regimes and is typically smaller than rho/sub i/, the ion Larmor radius. Previously accepted theories, which are based on the assumption Δvery-much-greater-thanrho/sub i/, are found to be valid only in the collisional regime. The effects of density and temperature gradients on the instabilities are also studied. The tearing instability is only driven by the temperature gradient in the collisional and semi-collisional regimes. Numerical calculations indicate that the semi-collisional tearing instability is particularly relevant to present day high temperature tokamak discharges

  12. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1997-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisaton of the damage, which...... as for the out-of-plane reaction force....

  13. Energy balance in tearing modes

    International Nuclear Information System (INIS)

    Wesson, J.A.

    1993-01-01

    The energy balance in tearing modes is described in terms of exact separate energy balance equations. Each of these equations describes identified physical processes, and their sum gives the conservation of total energy. One of the energy balance equations corresponds to Furth's description. (Author)

  14. Classification and localization of acetabular labral tears

    International Nuclear Information System (INIS)

    Blankenbaker, D.G.; De Smet, A.A.; Keene, J.S.; Fine, J.P.

    2007-01-01

    The purpose of this study was to compare the findings on hip MR arthrography (MRA) with the published MRA and arthroscopic classifications of hip labral tears and to evaluate a clock-face method for localizing hip labral tears. We retrospectively reviewed 65 hip MRA studies with correlative hip arthroscopies. Each labrum was evaluated on MRA using the classification system of Czerny and an MRA modification of the Lage arthroscopic classification. In addition, each tear was localized on MRA by using a clock-face description where 6 o'clock was the transverse ligament and 3 o'clock was anterior. These MRA findings were then correlated with the arthroscopic findings using the clock-face method of localization and the Lage arthroscopic classification of labral tears. At MRA, there were 42 Czerny grade 2 and 23 grade 3 labral tears and 22 MRA Lage type 1, 11 type 2, 22 type 3 and 10 type 4 tears. At arthroscopy, there were 10 Lage type 1 flap tears, 20 Lage type 2 fibrillated tears, 18 Lage type 3 longitudinal peripheral tears and 17 Lage type 4 unstable tears. The Czerny MRA classification and the modified MRA Lage classification had borderline correlation with the arthroscopic Lage classification. Localization of the tears using a clock-face description was within 1 o'clock of the arthroscopic localization of the tears in 85% of the patients. The Lage classification, which is the only published arthroscopic classification system for hip labral tears, does not correlate well with the Czerny MRA or an MRA modification of the Lage classification. Using a clock-face description to localize tears provides a way to accurately localize a labral tear and define its extent. (orig.)

  15. Tear osmolarity and dry eye symptoms in diabetics

    Directory of Open Access Journals (Sweden)

    Fuerst N

    2014-03-01

    Full Text Available Nicole Fuerst,1 Nicole Langelier,1 Mina Massaro-Giordano,1 Maxwell Pistilli,1 Kalliopi Stasi,1 Carrie Burns,2 Serena Cardillo,2 Vatinee Y Bunya1 1Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA; 2Division of Endocrinology, Diabetes, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA Purpose: To assess the relationship between tear osmolarity and dry eye symptoms in patients with diabetes. Patients and methods: Fifty patients with diabetes were enrolled. Demographic information and past medical history were recorded. Symptoms were assessed using the ocular surface disease index (OSDI. Tear osmolarity of each eye was measured with the TearLab® Osmolarity System. Results: The majority of the subjects were female (76%, African American (56%, and/or had a diagnosis of type 2 diabetes (82%. The mean ± standard deviation (SD for age was 54.6±13.4, and maximum tear osmolarity was 304.6±12.7 mOsm/L. Men had higher osmolarity than women (mean ± standard error (SE 311.8±4.0 mOsm/L versus 302.3±1.9 mOsm/L, P=0.02. Age, race, use of artificial tears, years of diabetes, and hemoglobin A1c did not have a statistically significant association with tear osmolarity. Longer duration of diabetes was associated with lower (less severe OSDI scores (r=-0.35, P=0.01. Higher tear osmolarity was associated with lower (less severe OSDI scores (r=-0.29, P=0.04. Conclusion: Approximately half of the diabetic subjects in our study had elevated tear osmolarity, and half of our population also reported symptoms consistent with dry eye disease. However, the two were slightly inversely related in that those with higher osmolarity reported fewer symptoms. Subjects with a longer duration of diabetes also reported fewer dry eye symptoms. Therefore, health care providers should be aware that patients who are most likely to have ocular surface disease, including those with

  16. Nonlinear tearing mode and vortex chains

    International Nuclear Information System (INIS)

    Jovanovic, D.; Vranjes, J.

    1996-01-01

    We study the nonlinear stage of a tearing mode, whose island width exceeds the tearing layer thickness, and the wavelength is of the order of collisionless skin depth. A coherent solution is found in the form of a moving vortex chain. It is the result of a self-organization process, which adjusts the profile of the sheared poloidal magnetic field and excites a localized perpendicular sheared plasma flow, consisting of three counterstreaming jets. A numerical solution shows a twin chain of plasma vortices, coupled with a single chain of magnetic islands, whose width is of the order of collisionless skin depth. Adiabatic evolution of the vortex chain in the presence of small viscosity reveals its finite lifetime. The chain destruction may occur either directly, or through a sequence of bifurcations (corresponding to abrupt changes of the vortex chain parameters) to magnetic field stochastization within a layer of the collisionless skin depth scale, which occurs before the magnetic island overlapping takes place. This provides a new mechanism for the anomalous transport. (orig.)

  17. Muscle architectural changes after massive human rotator cuff tear.

    Science.gov (United States)

    Gibbons, Michael C; Sato, Eugene J; Bachasson, Damien; Cheng, Timothy; Azimi, Hassan; Schenk, Simon; Engler, Adam J; Singh, Anshuman; Ward, Samuel R

    2016-12-01

    Rotator cuff (RC) tendon tears lead to negative structural and functional changes in the associated musculature. The structural features of muscle that predict function are termed "muscle architecture." Although the architectural features of "normal" rotator cuff muscles are known, they are poorly understood in the context of cuff pathology. The purpose of this study was to investigate the effects of tear and repair on RC muscle architecture. To this end thirty cadaveric shoulders were grouped into one of four categories based on tear magnitude: Intact, Full-thickness tear (FTT), Massive tear (MT), or Intervention if sutures or hardware were present, and key parameters of muscle architecture were measured. We found that muscle mass and fiber length decreased proportionally with tear size, with significant differences between all groups. Conversely, sarcomere number was reduced in both FTT and MT with no significant difference between these two groups, in large part because sarcomere length was significantly reduced in MT but not FTT. The loss of muscle mass in FTT is due, in part, to subtraction of serial sarcomeres, which may help preserve sarcomere length. This indicates that function in FTT may be impaired, but there is some remaining mechanical loading to maintain "normal" sarcomere length-tension relationships. However, the changes resulting from MT suggest more severe limitations in force-generating capacity because sarcomere length-tension relationships are no longer normal. The architectural deficits observed in MT muscles may indicate deeper deficiencies in muscle adaptability to length change, which could negatively impact RC function despite successful anatomical repair. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2089-2095, 2016. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  18. Selective Laser Sintering of PA2200: Effects of print parameters on density, accuracy, and surface roughness

    Energy Technology Data Exchange (ETDEWEB)

    Bajric, Sendin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-06-12

    Additive manufacturing needs a broader selection of materials for part production. In order for the Los Alamos National Laboratory (LANL) to investigate new materials for selective laser sintering (SLS), this paper reviews research on the effect of print parameters on part density, accuracy, and surface roughness of polyamide 12 (PA12, PA2200). The literature review serves to enhance the understanding of how changing the laser powder, scan speed, etc. will affect the mechanical properties of a commercial powder. By doing so, this understanding will help the investigation of new materials for SLS.

  19. A Modelling Method of Bolt Joints Based on Basic Characteristic Parameters of Joint Surfaces

    Science.gov (United States)

    Yuansheng, Li; Guangpeng, Zhang; Zhen, Zhang; Ping, Wang

    2018-02-01

    Bolt joints are common in machine tools and have a direct impact on the overall performance of the tools. Therefore, the understanding of bolt joint characteristics is essential for improving machine design and assembly. Firstly, According to the experimental data obtained from the experiment, the stiffness curve formula was fitted. Secondly, a finite element model of unit bolt joints such as bolt flange joints, bolt head joints, and thread joints was constructed, and lastly the stiffness parameters of joint surfaces were implemented in the model by the secondary development of ABAQUS. The finite element model of the bolt joint established by this method can simulate the contact state very well.

  20. The Diagnosis of Plasma Parameters in Surface Alloying Technique by Optical Emission Spectrometry

    International Nuclear Information System (INIS)

    Fu Yabo; Zhang Yuefei; Chen Qiang; Zhang Guangqiu; Gao Yuan; Wang Jianzhong; Kui Xiaoyun

    2006-01-01

    Electron density (Ne) in a glow discharge plasma for the surface alloying technique is diagnosed by optical emission spectrometry (OES). With CH 4 as the feeding gas, Ne is obtained by comparing the Hβ spectrum according to the Stark broadening effect. It is noticed that Ne varies with the working pressures (30 Pa to 70 Pa) and cathode voltages (500 V to 1000 V), respectively. Due to an abnormal glow discharge, Ne is between 1.71x10 15 /cm 3 to 6.64x10 15 /cm 3 and increases rapidly with working gas pressures and cathode voltages. The results show that OES is a useful method to measure the plasma parameters in a surface alloying glow discharge plasma

  1. Nonlinear estimation of weathering rate parameters for uranium in surface soil near a nuclear facility

    International Nuclear Information System (INIS)

    Killough, G.G.; Rope, S.K.; Shleien, B.; Voilleque, P.G.

    1999-01-01

    A dynamic mass-balance model has been calibrated by a nonlinear parameter estimation method, using time-series measurements of uranium in surface soil near the former Feed Materials Production Center (FMPC) near Fernald, Ohio, USA. The time-series data, taken at six locations near the site boundary since 1971, show a statistically significant downtrend of above-background uranium concentration in surface soil for all six locations. The dynamic model is based on first-order kinetics in a surface-soil compartment 10 cm in depth. Median estimates of weathering rate coefficients for insoluble uranium in this soil compartment range from about 0.065-0.14 year -1 , corresponding to mean transit times of about 7-15 years, depending on the location sampled. The model, calibrated by methods similar to those discussed in this paper, has been used to simulate surface soil kinetics of uranium for a dose reconstruction study. It was also applied, along with other data, to make confirmatory estimates of airborne releases of uranium from the FMPC between 1951 and 1988. Two soil-column models (one diffusive and one advective, the latter similar to a catenary first-order kinetic box model) were calibrated to profile data taken at one of the six locations in 1976. The temporal predictions of the advective model approximate the trend of the time series data for that location. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  2. Effect of contact lens wear and a near task on tear film break-up.

    Science.gov (United States)

    Jansen, Meredith E; Begley, Carolyn G; Himebaugh, Nikole H; Port, Nicholas L

    2010-05-01

    To study the effect of extrinsic controls on blinking by examining blink parameters and tear stability among adapted soft contact lens (CL) wearers performing tasks that require varying amounts of visual concentration. The Demographic Questionnaire, Contact Lens Dry Eye Questionnaire, and Current Symptoms Questionnaire were completed by 15 adapted soft CL wearers (nine females). Three 55 s simultaneous measurements of tear film stability via retroillumination and blinking were obtained with a slit-lamp biomicroscope and 200 Hz video camera while subjects listened to music and played a video game with and without their habitual CLs. Interblink interval (IBI) and blink amplitude (BA) were calculated. The area of break-up (AB) was calculated for the retroillumination image before each blink. The Current Symptoms Questionnaire was completed four times throughout testing. With the game compared to music, IBI was significantly longer and BA significantly decreased without CLs (p or = 0.5579, p or = 0.6262, p or = 0.5064, p film instability increased. Blinking frequency also increased, but it remained high when subjects played the game, and symptoms of ocular irritation increased. This suggests that wearing soft CLs, even when fully adapted, provides enough extrinsic ocular surface stimulation to override internal controls and affect blink parameters.

  3. Ultrasound determination of rotator cuff tear repairability

    Science.gov (United States)

    Tse, Andrew K; Lam, Patrick H; Walton, Judie R; Hackett, Lisa

    2015-01-01

    Background Rotator cuff repair aims to reattach the torn tendon to the greater tuberosity footprint with suture anchors. The present study aimed to assess the diagnostic accuracy of ultrasound in predicting rotator cuff tear repairability and to assess which sonographic and pre-operative features are strongest in predicting repairability. Methods The study was a retrospective analysis of measurements made prospectively in a cohort of 373 patients who had ultrasounds of their shoulder and underwent rotator cuff repair. Measurements of rotator cuff tear size and muscle atrophy were made pre-operatively by ultrasound to enable prediction of rotator cuff repairability. Tears were classified following ultrasound as repairable or irreparable, and were correlated with intra-operative repairability. Results Ultrasound assessment of rotator cuff tear repairability has a sensitivity of 86% (p tear size (p tear size ≥4 cm2 or anteroposterior tear length ≥25 mm indicated an irreparable rotator cuff tear. Conclusions Ultrasound assessment is accurate in predicting rotator cuff tear repairability. Tear size or anteroposterior tear length and age were the best predictors of repairability. PMID:27582996

  4. [Neuronal and hormonal regulatory mechanisms of tears production and secretion].

    Science.gov (United States)

    Mrugacz, Małgorzata; Zywalewska, Nella; Bakunowicz-Lazarczyk, Alina

    2005-01-01

    The ocular surface, tear film, lacrimal glands act as a functional unit to preserve the quality of the refractive surface of the eye, and to resist injury and protect the eye against bodily and environmental conditions. Homeostasis of this functional unit involves neuronal and hormonal regulatory mechanisms. The eye appears to be a target organ for sex hormones particulary the androgen, as they modulate the immune system and trophic functions of the lacrimal and Meibomian glands.

  5. Hot tearing studies in AA5182

    Science.gov (United States)

    van Haaften, W. M.; Kool, W. H.; Katgerman, L.

    2002-10-01

    One of the major problems during direct chill (DC) casting is hot tearing. These tears initiate during solidification of the alloy and may run through the entire ingot. To study the hot tearing mechanism, tensile tests were carried out in semisolid state and at low strain rates, and crack propagation was studied in situ by scanning electron microscopy (SEM). These experimentally induced cracks were compared with hot tears developed in an AA5182 ingot during a casting trial in an industrial research facility. Similarities in the microstructure of the tensile test specimens and the hot tears indicate that hot tearing can be simulated by performing tensile tests at semisolid temperatures. The experimental data were compared with existing hot tearing models and it was concluded that the latter are restricted to relatively high liquid fractions because they do not take into account the existence of solid bridges in the crack.

  6. Analysis of tear cytokines and clinical correlations in Sjögren syndrome dry eye patients and non-Sjögren syndrome dry eye patients.

    Science.gov (United States)

    Lee, Sang Yeop; Han, Soo Jung; Nam, Sang Min; Yoon, Sang Chul; Ahn, Ji Min; Kim, Tae-Im; Kim, Eung Kweon; Seo, Kyoung Yul

    2013-08-01

    To compare concentrations of tear cytokines in 3 groups composed of Sjögren syndrome (SS) dry eye, non-Sjögren syndrome (non-SS) dry eye, and normal subjects. Correlations between ocular surface parameters and tear cytokines were also investigated. Prospective cross-sectional study. SS dry eye patients (n = 24; 40 eyes) were diagnosed with primary SS according to the criteria set by the American-European Consensus Group. Non-SS dry eye patients (n = 25; 40 eyes) and normal subjects (n = 21; 35 eyes) were also enrolled. Tear concentrations of interleukin (IL)-17, IL-6, IL-10, IL-4, IL-2, interferon γ (IFN-γ), and tumor necrosis factor α (TNF-α) were measured by a multiplex immunobead assay. Ocular Surface Disease Index (OSDI), tear film breakup time (TBUT), Schirmer I test, and fluorescein staining scores were obtained from dry eye patients. All cytokine levels except for IL-2 were highest in the SS group, followed by non-SS dry eye group and control subjects. Concentrations of IL-17, TNF-α, and IL-6 were significantly different among the 3 groups (IL-17: SS > control P control P = .042, SS > non-SS P control P = .006, non-SS > control P = .034, SS > non-SS P = .029; IL-6: SS > control P = .002, non-SS > control P = .032, SS > non-SS P = .002). IL-17 was significantly correlated with TBUT (R = -0.22, P = .012) and Schirmer I test (R = -0.36, P = .027) scores in the SS group. IL-6 was significantly correlated only with TBUT (R = -0.38, P = .02) in the non-SS group. Differences in tear cytokine levels and correlation patterns between SS dry eye and non-SS dry eye patients suggest the involvement of different inflammatory processes as causes of dry eye syndrome. Copyright © 2013 Elsevier Inc. All rights reserved.

  7. Research of state of metal welded joint by deformation and corrosion surface projection parameters

    Directory of Open Access Journals (Sweden)

    Demchenko Maria Vyacheslavovna

    2017-10-01

    Full Text Available At industrial enterprises in building structures and equipment one can see corrosion damage, as well as damage accumulated during operation period. The areas of stress concentration are welded joints as their structure is heterogeneous. From the point of view of the scale hierarchy, the welded joint represents the welded and base metal zones at the meso-macrolevel, the weld zone, the thermal zone, the base metal at the micro-mesolevel, the grain constituents at the nano-microlevel. Borders are the stress concentrators at different scale levels, thus they becomes the most dangerous places of metal structure. Modeling by the molecular dynamics method at the atomic level has shown nanocracks initiation in triple junctions of grain boundaries and on the ledges of the grain boundaries. Due to active development of nanotechnology, it became possible to evaluate the state of the weld metal at the nanoscale, where irreversible changes take place from the very beginning. Existing methods of nondestructive testing can detect damage only at the meso- and macrolevel. Modern equipment makes it possible to use other methods of control and approaches. For example, according to GOST R55046-2012 and R57223-2016, the analysis of the parameters of the surface projection deformation performed by confocal laser scanning microscopy should be taken into account when the evaluation of state of metal pipelines is carried out. However, there is a problem to monitore it due to various factors affecting the surface during operation. The paper proposes an additional method to estimate the state of weld metal at any stage of deformation that uses 3D analysis of the parameters of the «artificial» corrosion relief of surface. During the operation period changes in the stress-strain state and structure of the metal take place, as the result the character and depth of etching of the grains of the structural components and their boundaries change too. Evaluation of the

  8. Selecting the thermo-cyclic treatment’s optimum parameters based analysis of fractal surfaces indicators

    Directory of Open Access Journals (Sweden)

    Вікторія Юріївна Іващенко

    2015-03-01

    Full Text Available Optimization of complex modes of heat treatments, in which control the properties of processed steel occurs by varying the large number of parameters, is quite time-consuming process. The influence of thermal processes on the formation of the metal structure manifested at the level of micro- and meso-sizes, which are realized qualitatively different mechanisms of destruction. Method of multi-factual description of the fracture’s surfaces, which was got after tests of mechanical properties, was used for the choice of the optimum thermo-cyclic mode with the variable temperatures Tmax and Tmin in cycles in this work. It vas founded the number of TCT-mode’s cycles and order changing Tmax affect the processes of dislocation motion and the formation of micro-voids in the metal. This work shows the relationship between these processes and fractal indices. Fractal indices of micro levels correlate to the dislocation density of the structure, and the meso-level indices - to the percentage reduction of area at fracture. It was proved that the analysis of the topography of the fracture’s surfaces using fractal indices to determine the optimal combination of processing parameters required to obtain the best mechanical properties. The new TCT-modes with variable temperature settings can be seen as reinforcing thermal technology that promotes self-organization phase-structural state of steels because it is able to generate an effective barrier to the movement of dislocations and cracks promotion

  9. Synergistic estimation of surface parameters from jointly using optical and microwave observations in EOLDAS

    Science.gov (United States)

    Timmermans, Joris; Gomez-Dans, Jose; Lewis, Philip; Loew, Alexander; Schlenz, Florian

    2017-04-01

    The large amount of remote sensing data nowadays available provides a huge potential for monitoring crop development, drought conditions and water efficiency. This potential however not been realized yet because algorithms for land surface parameter retrieval mostly use data from only a single sensor. Consequently products that combine different low-level observations from different sensors are hard to find. The lack of synergistic retrieval is caused because it is easier to focus on single sensor types/footprints and temporal observation times, than to find a way to compensate for differences. Different sensor types (microwave/optical) require different radiative transfer (RT) models and also require consistency between the models to have any impact on the retrieval of soil moisture by a microwave instrument. Varying spatial footprints require first proper collocation of the data before one can scale between different resolutions. Considering these problems, merging optical and microwave observations have not been performed yet. The goal of this research was to investigate the potential of integrating optical and microwave RT models within the Earth Observation Land Data Assimilation System (EOLDAS) synergistically to derive biophysical parameters. This system uses a Bayesian data assimilation approach together with observation operators such as the PROSAIL model to estimate land surface parameters. For the purpose of enabling the system to integrate passive microwave radiation (from an ELBARRA II passive microwave radiometer), the Community Microwave Emission Model (CMEM) RT-model, was integrated within the EOLDAS system. In order to quantify the potential, a variety of land surface parameters was chosen to be retrieved from the system, in particular variables that a) impact only optical RT (such as leaf water content and leaf dry matter), b) only impact the microwave RT (such as soil moisture and soil temperature), and c) Leaf Area Index (LAI) that impacts both

  10. Bead-bead interaction parameters in dissipative particle dynamics: Relation to bead-size, solubility parameter, and surface tension

    Science.gov (United States)

    Maiti, Amitesh; McGrother, Simon

    2004-01-01

    Dissipative particle dynamics (DPD) is a mesoscale modeling method for simulating equilibrium and dynamical properties of polymers in solution. The basic idea has been around for several decades in the form of bead-spring models. A few years ago, Groot and Warren [J. Chem. Phys. 107, 4423 (1997)] established an important link between DPD and the Flory-Huggins χ-parameter theory for polymer solutions. We revisit the Groot-Warren theory and investigate the DPD interaction parameters as a function of bead size. In particular, we show a consistent scheme of computing the interfacial tension in a segregated binary mixture. Results for three systems chosen for illustration are in excellent agreement with experimental results. This opens the door for determining DPD interactions using interfacial tension as a fitting parameter.

  11. Evaluation of the tear film stability after laser in situ keratomileusis using the tear film stability analysis system.

    Science.gov (United States)

    Goto, Tomoko; Zheng, Xiaodong; Klyce, Stephen D; Kataoka, Hisashi; Uno, Toshihiko; Yamaguchi, Masahiko; Karon, Mike; Hirano, Sumie; Okamoto, Shigeki; Ohashi, Yuichi

    2004-01-01

    To evaluate the tear film stability of patients before and after laser in situ keratomileusis (LASIK) using the tear film stability analysis system (TSAS). Prospective observational case series. New videokeratography software for a topographic modeling system (TMS-2N) was developed that can automatically capture consecutive corneal surface images every second for 10 seconds. Thirty-four subjects (64 eyes) who underwent myopia LASIK were enrolled in this study. All subjects were examined with the new system before LASIK and at 1 week, 1 month, 3 months, and 6 months after the surgery. Corneal topographs were analyzed for tear breakup time (TMS breakup time) and breakup area (TMS breakup area). Based on pre-LASIK TSAS analysis, subjects were separated into normal and abnormal TSAS value groups. The criteria for the normal group were either TMS breakup time more than 5 seconds or TMS breakup area less than 0.2. The percentage of the occurrence of superficial punctuate keratitis was compared between the two groups with regard to subject's dry eye signs and symptoms. Tear film stability decreased significantly during the early period after LASIK, as indexed by decreased TMS breakup time and increased TMS breakup area. Tear film instability resolved at 6 months after surgery. Before LASIK, 22 subjects (43 eyes) had normal TSAS evaluation and 12 subjects (21 eyes) were abnormal. After LASIK, among normal TSAS value eyes, 8 of 43 (18.6%) eyes developed superficial punctuate keratitis. In sharp contrast, 14 of 21 (66.7%) eyes in the abnormal group displayed superficial punctuate keratitis, correlating well with the patients' dry eye symptoms. The difference in the presence of superficial punctuate keratitis after LASIK between normal and abnormal TSAS value groups was statistically significant (P <.001). Subjects with abnormal TSAS evaluation also displayed resistance to dry eye treatment and had extended period of recovery. Tear film stability analysis can be a useful

  12. Effect of process parameters on surface oxides on chromium-alloyed steel powder during sintering

    International Nuclear Information System (INIS)

    Chasoglou, D.; Hryha, E.; Nyborg, L.

    2013-01-01

    The use of chromium in the PM steel industry today puts high demands on the choice and control of the atmosphere during the sintering process due to its high affinity to oxygen. Particular attention is required in order to control the surface chemistry of the powder which in turn is the key factor for the successful sintering and production of PM parts. Different atmosphere compositions, heating rates and green densities were employed while performing sintering trials on water atomized steel powder pre-alloyed with 3 wt.% Cr in order to evaluate the effect on surface chemical reactions. Fracture surfaces of sintered samples were examined using high resolution scanning electron microscopy combined with X-ray microanalysis. The investigation was complemented with thermogravimetric (TG) studies. Reaction products in particulate form containing strong-oxide forming elements such as Cr, Si and Mn were formed during sintering for all conditions. Processing in vacuum results in intensive inter-particle neck development during the heating stage and consequently in the excessive enclosure of surface oxide which is reflected in less good final mechanical properties. Enhanced oxide reduction was observed in samples processed in hydrogen-containing atmospheres independent of the actual content in the range of 3–10 vol.%. An optimum heating rate was required for balancing reduction/oxidation processes. A simple model for the enclosure and growth of oxide inclusions during the sinter-neck development is proposed. The obtained results show that significant reduction of the oxygen content can be achieved by adjusting the atmosphere purity/composition. - Highlights: ► A local atmosphere microclimate is very important for sintering of PM steels. ► High risk of surface oxide enclosure between 800 and 1000 °C. ► Coalescence and agglomeration of enclosed oxides take place during sintering. ► The effect of different process parameters on the oxide reduction is examined. ► A

  13. Change of surface colour parameters during storage of paprika (Capsicum annuum L.

    Directory of Open Access Journals (Sweden)

    Belović Miona M.

    2014-01-01

    Full Text Available The change of paprika surface colour during three years of storage was monitored by measuring CIEL*a*b* colour parameters once a year. Ten commercial and three branded paprika samples, originating from Hungary, Austria and Serbia, were stored in original packaging at ambient temperature in dark during the storage period. The colour of paprika powder was measured by Chroma Meter CR-400 (Konica Minolta, Japan, using attachment for granular materials CR-A50. Directly measured colour parameters were CIE L* (lightness, a* (+a* = redness, -a* = greenness, b* (+b* = yellowness, -b* = blueness and dominant wavelength (DWL, while derived colour parameters were chroma (C*, hue angle (h°, and total colour change (ΔE. Paprika samples had similar granulation, and therefore it was concluded that it did not influence the colour reflection. The change of reflected colour of paprika powder during storage can be characterized by increase of CIE L* and b* colour values and decrease of a* colour value. Therefore, chroma values remained almost unchanged, while hue angle showed shift in spectrum from red-orange to orange-yellow, similarly to dominant wavelength. The paprika samples changed their colour most rapidly during the first year of storage, except the branded paprika from Serbia. Commercial paprika samples from Serbian market changed their colour more rapidly comparing to other investigated samples.

  14. Modulation of surface meteorological parameters by extratropical planetary-scale Rossby waves

    Directory of Open Access Journals (Sweden)

    K. Niranjan Kumar

    2016-01-01

    Full Text Available This study examines the link between upper-tropospheric planetary-scale Rossby waves and surface meteorological parameters based on the observations made in association with the Ganges Valley Aerosol Experiment (GVAX campaign at an extratropical site at Aryabhatta Research Institute of Observational Sciences, Nainital (29.45° N, 79.5° E during November–December 2011. The spectral analysis of the tropospheric wind field from radiosonde measurements indicates a predominance power of around 8 days in the upper troposphere during the observational period. An analysis of the 200 hPa meridional wind (v200 hPa anomalies from the Modern-Era Retrospective Analysis for Research and Applications (MERRA reanalysis shows distinct Rossby-wave-like structures over a high-altitude site in the central Himalayan region. Furthermore, the spectral analysis of global v200 hPa anomalies indicates the Rossby waves are characterized by zonal wave number 6. The amplification of the Rossby wave packets over the site leads to persistent subtropical jet stream (STJ patterns, which further affects the surface weather conditions. The propagating Rossby waves in the upper troposphere along with the undulations in the STJ create convergence and divergence regions in the mid-troposphere. Therefore, the surface meteorological parameters such as the relative humidity, wind speeds, and temperature are synchronized with the phase of the propagating Rossby waves. Moreover, the present study finds important implications for medium-range forecasting through the upper-level Rossby waves over the study region.

  15. Satellite-derived land surface parameters for mesoscale modelling of the Mexico City basin

    Directory of Open Access Journals (Sweden)

    B. de Foy

    2006-01-01

    Full Text Available Mesoscale meteorological modelling is an important tool to help understand air pollution and heat island effects in urban areas. Accurate wind simulations are difficult to obtain in areas of weak synoptic forcing. Local factors have a dominant role in the circulation and include land surface parameters and their interaction with the atmosphere. This paper examines an episode during the MCMA-2003 field campaign held in the Mexico City Metropolitan Area (MCMA in April of 2003. Because the episode has weak synoptic forcing, there is the potential for the surface heat budget to influence the local meteorology. High resolution satellite observations are used to specify the land use, vegetation fraction, albedo and surface temperature in the MM5 model. Making use of these readily available data leads to improved meteorological simulations in the MCMA, both for the wind circulation patterns and the urban heat island. Replacing values previously obtained from land-use tables with actual measurements removes the number of unknowns in the model and increases the accuracy of the energy budget. In addition to improving the understanding of local meteorology, this sets the stage for the use of advanced urban modules.

  16. Lateral Trunk Surface as a new parameter to estimate live body weight by Visual Image Analysis

    Directory of Open Access Journals (Sweden)

    S. Terramoccia

    2010-02-01

    Full Text Available Live weight of 74 milking Mediterranean buffaloes (Bubalus bubalis L. have been estimated by Visual Image Analysis. The total surface of lateral profile, tested in previous researches with viable result, was substituted by the measurement of the Lateral Trunk Surface (LTrS. The measurements were recorded by a camera equipped by a laser distance recorder and data were elaborated by a specific software. This parameter, eliminating the surface of neck, head and legs, that are less easily measurable, simplified and accelerated the procedure. Correlation between LTrS and live weight was r = 0.90 (P < 0.01. A significant equation (P < 0.01 was obtained from the recorded data of a random sample of 38 buffaloes. When the validation of the equation was tested on the other 36 subjects, the estimated live weight had a mean of 691.74 kg ± 68.55. This was corresponding to a 1.08% overestimation of the real weight.

  17. Image-based Exploration of Iso-surfaces for Large Multi- Variable Datasets using Parameter Space.

    KAUST Repository

    Binyahib, Roba S.

    2013-05-13

    With an increase in processing power, more complex simulations have resulted in larger data size, with higher resolution and more variables. Many techniques have been developed to help the user to visualize and analyze data from such simulations. However, dealing with a large amount of multivariate data is challenging, time- consuming and often requires high-end clusters. Consequently, novel visualization techniques are needed to explore such data. Many users would like to visually explore their data and change certain visual aspects without the need to use special clusters or having to load a large amount of data. This is the idea behind explorable images (EI). Explorable images are a novel approach that provides limited interactive visualization without the need to re-render from the original data [40]. In this work, the concept of EI has been used to create a workflow that deals with explorable iso-surfaces for scalar fields in a multivariate, time-varying dataset. As a pre-processing step, a set of iso-values for each scalar field is inferred and extracted from a user-assisted sampling technique in time-parameter space. These iso-values are then used to generate iso- surfaces that are then pre-rendered (from a fixed viewpoint) along with additional buffers (i.e. normals, depth, values of other fields, etc.) to provide a compressed representation of iso-surfaces in the dataset. We present a tool that at run-time allows the user to interactively browse and calculate a combination of iso-surfaces superimposed on each other. The result is the same as calculating multiple iso- surfaces from the original data but without the memory and processing overhead. Our tool also allows the user to change the (scalar) values superimposed on each of the surfaces, modify their color map, and interactively re-light the surfaces. We demonstrate the effectiveness of our approach over a multi-terabyte combustion dataset. We also illustrate the efficiency and accuracy of our

  18. Dynamic measurement of the corneal tear film with a Twyman-Green interferometer

    Science.gov (United States)

    Micali, Jason D.; Greivenkamp, John E.; Primeau, Brian C.

    2015-05-01

    An interferometer for measuring dynamic properties of the in vivo tear film on the human cornea has been developed. The system is a near-infrared instantaneous phase-shifting Twyman-Green interferometer. The laser source is a 785 nm solid-state laser, and the system has been carefully designed and calibrated to ensure that the system operates at eye-safe levels. Measurements are made over a 6 mm diameter on the cornea. Successive frames of interferometric height measurements are combined to produce movies showing both the quantitative and qualitative changes in the topography of the tear film surface and structure. To date, measurement periods of up to 120 s at 28.6 frames per second have been obtained. Several human subjects have been examined using this system, demonstrating a surface height resolution of 25 nm and spatial resolution of 6 μm. Examples of features that have been observed in these preliminary studies of the tear film include postblink disruption, evolution, and stabilization of the tear film; tear film artifacts generated by blinking; tear film evaporation and breakup; and the propagation of foreign objects in the tear film. This paper discusses the interferometer design and presents results from in vivo measurements.

  19. Incomplete response to artificial tears is associated with features of neuropathic ocular pain.

    Science.gov (United States)

    Galor, Anat; Batawi, Hatim; Felix, Elizabeth R; Margolis, Todd P; Sarantopoulos, Konstantinos D; Martin, Eden R; Levitt, Roy C

    2016-06-01

    Artificial tears are first-line therapy for patients with dry eye symptoms. It is not known, however, which patient factors associate with a positive response to therapy. The purpose of this study was to evaluate whether certain ocular and systemic findings are associated with a differential subjective response to artificial tears. Cross-sectional study of 118 individuals reporting artificial tears use (hypromellose 0.4%) to treat dry eye-associated ocular pain. An evaluation was performed to assess dry eye symptoms (via the dry eye questionnaire 5 and ocular surface disease index), ocular and systemic (non-ocular) pain complaints and ocular signs (tear osmolarity, tear breakup time, corneal staining, Schirmer testing with anaesthesia, and eyelid and meibomian gland assessment). The main outcome measures were factors associated with differential subjective response to artificial tears. By self-report, 23 patients reported no improvement, 73 partial improvement and 22 complete improvement in ocular pain with artificial tears. Patients who reported no or partial improvement in pain with artificial tears reported higher levels of hot-burning ocular pain and sensitivity to wind compared with those with complete improvement. Patients were also asked to rate the intensity of systemic pain elsewhere in the body (other than the eye). Patients who reported no or incomplete improvement with artificial tears had higher systemic pain scores compared with those with complete improvement. Both ocular and systemic (non-ocular) pain complaints are associated with a differential subjective response to artificial tears. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

  20. Oxidative Stress Measures of Lipid and DNA Damage in Human Tears.

    Science.gov (United States)

    Haworth, Kristina M; Chandler, Heather L

    2017-05-01

    We evaluate feasibility and repeatability of measures for lipid peroxidation and DNA oxidation in human tears, as well as relationships between outcome variables, and compared our findings to previously reported methods of evaluation for ocular sun exposure. A total of 50 volunteers were seen for 2 visits 14 ± 2 days apart. Tear samples were collected from the inferior tear meniscus using a glass microcapillary tube. Oxidative stress biomarkers were quantified using enzyme-linked immunosorbent assay (ELISA): lipid peroxidation by measurement of hexanoyl-lysine (HEL) expression; DNA oxidation by measurement of 8-oxo-2'-deoxyguinosone (8OHdG) expression. Descriptive statistics were generated. Repeatability estimates were made using Bland-Altman plots with mean differences and 95% limits of agreement were calculated. Linear regression was conducted to evaluate relationships between measures. Mean (±SD) values for tear HEL and 8OHdG expression were 17368.02 (±9878.42) nmol/L and 66.13 (±19.99) ng/mL, respectively. Repeatability was found to be acceptable for both HEL and 8OHdG expression. Univariate linear regression supported tear 8OHdG expression and spring season of collection to be predictors of higher tear HEL expression; tear HEL expression was confirmed as a predictor of higher tear 8OHdG expression. We demonstrate feasibility and repeatability of estimating previously unreported tear 8OHdG expression. Seasonal temperature variation and other factors may influence tear lipid peroxidation. Support is demonstrated to suggest lipid damage and DNA damage occur concurrently on the human ocular surface.

  1. High-speed infrared thermography for the measurement of microscopic boiling parameters on micro- and nano-structured surfaces

    International Nuclear Information System (INIS)

    Park, Youngjae; Kim, Hyungdae; Kim, Hyungmo; Kim, Joonwon

    2014-01-01

    Micro- and nano-scale structures on boiling surfaces can enhance nucleate boiling heat transfer coefficient (HTC) and critical heat flux (CHF). A few studies were conducted to explain the enhancements of HTC and CHF using the microscopic boiling parameters. Quantitative measurements of microscopic boiling parameters are needed to understand the physical mechanism of the boiling heat transfer augmentation on structured surfaces. However, there is no existing experimental techniques to conveniently measure the boiling parameters on the structured surfaces because of the small (surfaces. The visualization results are analyzed to obtain the microscopic boiling parameters. Finally, quantitative microscopic boiling parameters are used to interpret the enhancement of HTC and CHF. In this study, liquid-vapor phase distributions of each surface were clearly visualized by IR thermography during the nucleate boiling phenomena. From the visualization results, following microscopic boiling parameters were quantitatively measured by image processing. - Number density of dry patch, NDP IR thermography technique was demonstrated by nucleate pool boiling experiments with M- and N surfaces. The enhancement of HTC and CHF could be explained by microscopic boiling parameters

  2. Stability of coupled tearing and twisting modes in tokamaks

    International Nuclear Information System (INIS)

    Fitzpatrick, R.

    1994-03-01

    A dispersion relation is derived for resistive modes of arbitrary parity in a tokamak plasma. At low mode amplitude, tearing and twisting modes which have nonideal MHD behavior at only one rational surface at a time in the plasma are decoupled via sheared rotation and diamagnetic flows. At higher amplitude, more unstable open-quote compound close-quote modes develop which have nonideal behavior simultaneously at many surfaces. Such modes possess tearing parity layers at some of the nonideal surfaces, and twisting parity layers at others, but mixed parity layers are generally disallowed. At low mode number, open-quote compound close-quote modes are likely to have tearing parity layers at all of the nonideal surfaces in a very low-β plasma, but twisting parity layers become more probable as the plasma β is increased. At high mode number, unstable twisting modes which exceed a critical amplitude drive conventional magnetic island chains on alternate rational surfaces, to form an interlocking structure in which the O-points and X-points of neighboring chains line up

  3. Plate Tearing by a Cone

    DEFF Research Database (Denmark)

    Simonsen, Bo Cerup

    1998-01-01

    The present paper is concerned with steady-state plate tearing by a cone. This is a scenario where a cone is forced through a ductile metal plate with a constant lateral tip penetration in a motion in the plane of the plate. The considered process could be an idealisation of the damage, which...... as for the out-of-plane reaction force. (C) 1998 Elsevier Science Ltd. All rights reserved....

  4. Non-invasive pre-lens tear film assessment with high-speed videokeratoscopy.

    Science.gov (United States)

    Llorens-Quintana, Clara; Mousavi, Maryam; Szczesna-Iskander, Dorota; Iskander, D Robert

    2018-02-01

    To evaluate the effect of two types of daily contact lenses (delefilcon A and omafilcon A) on the tear film and establish whether it is dependent on pre-corneal tear film characteristics using a new method to analyse high-speed videokeratoscopy recordings, as well as to determine the sensitivity of the method in differentiating between contact lens materials on eye. High-speed videokeratoscopy recordings were analysed using a custom made automated algorithm based on a fractal dimension approach that provides a set of parameters directly related to tear film stability. Fifty-four subjects participated in the study. Baseline measurements, in suppressed and natural blinking conditions, were taken before subjects were fitted with two different daily contact lenses and after four hours of contact lens wear. The method for analysing the stability of the tear film provides alternative parameters to the non-invasive break up time to assess the quality of the pre-corneal and pre-lens tear film. Both contact lenses significantly decreased the quality of the tear film in suppressed and natural blinking conditions (pfilm characteristics were not correlated with the decrease in pre-lens tear film quality. High-speed videokeratoscopy equipped with an automated method to analyse the dynamics of the tear film is able to distinguish between contact lens materials in vivo. Incorporating the assessment of pre-lens tear film to the clinical practice could aid improving contact lens fitting and understand contact lens comfort. Copyright © 2017 British Contact Lens Association. Published by Elsevier Ltd. All rights reserved.

  5. Experimental Research and Mathematical Modeling of Parameters Effecting on Cutting Force and SurfaceRoughness in CNC Turning Process

    Science.gov (United States)

    Zeqiri, F.; Alkan, M.; Kaya, B.; Toros, S.

    2018-01-01

    In this paper, the effects of cutting parameters on cutting forces and surface roughness based on Taguchi experimental design method are determined. Taguchi L9 orthogonal array is used to investigate the effects of machining parameters. Optimal cutting conditions are determined using the signal/noise (S/N) ratio which is calculated by average surface roughness and cutting force. Using results of analysis, effects of parameters on both average surface roughness and cutting forces are calculated on Minitab 17 using ANOVA method. The material that was investigated is Inconel 625 steel for two cases with heat treatment and without heat treatment. The predicted and calculated values with measurement are very close to each other. Confirmation test of results showed that the Taguchi method was very successful in the optimization of machining parameters for maximum surface roughness and cutting forces in the CNC turning process.

  6. Coupling of tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Finn, J.M.

    1977-01-01

    The simultaneous presence of tearing modes of different helical pitches leads to the destruction of magnetic surfaces, which has been suggested as the mechanism leading to the onset of the disruptive instability in tokamaks. For current profiles in which the m = 2 mode is unstable, but the m = 3 is stable, the coupling of the m = 3 to the m = 2 through the poloidal variation of the toroidal field can drive the m = 3 amplitude psi 3 to order psi 2 times the inverse aspect ratio. Detailed calculations, both analytical and numerical, have been performed for two models for the equilibrium and m = 2 mode structure. A slab model and incompressible m = 3 perturbations are assumed. The m = 3 amplitude increases with shear, up to a point, showing that as the current channel shrinks, overlap of resonances becomes more likely. The results also apply qualitatively to other m, m +- 1 interactions

  7. Modelling the evaporation of a tear film over a contact lens.

    Science.gov (United States)

    Talbott, Kevin; Xu, Amber; Anderson, Daniel M; Seshaiyer, Padmanabhan

    2015-06-01

    A contact lens (CL) separates the tear film into a pre-lens tear film (PrLTF), the fluid layer between the CL and the outside environment, and a post-lens tear film (PoLTF), the fluid layer between the CL and the cornea. We examine a model for evaporation of a PrLTF on a modern permeable CL allowing fluid transfer between the PrLTF and the PoLTF. Evaporation depletes the PrLTF, and continued evaporation causes depletion of the PoLTF via fluid loss through the CL. Governing equations include Navier-Stokes, heat and Darcy's equations for the fluid flow and heat transfer in the PrLTF and porous layer. The PoLTF is modelled by a fixed pressure condition on the posterior surface of the CL. The original model is simplified using lubrication theory for the PrLTF and CL applied to a sagittal plane through the eye. We obtain a partial differential equation (PDE) for the PrLTF thickness that is first-order in time and fourth-order in space. This model incorporates evaporation, conjoining pressure effects in the PrLTF, capillarity and heat transfer. For a planar film, we find that this PDE can be reduced to an ordinary differential equation (ODE) that can be solved analytically or numerically. This reduced model allows for interpretation of the various system parameters and captures most of the basic physics contained in the model. Comparisons of ODE and PDE models, including estimates for the loss of fluid through the lens due to evaporation, are given. © The Authors 2014. Published by Oxford University Press on behalf of the Institute of Mathematics and its Applications. All rights reserved.

  8. The growth of the tearing mode - Boundary and scaling effects

    Science.gov (United States)

    Steinolfson, R. S.; Van Hoven, G.

    1983-01-01

    A numerical model of resistive magnetic tearing is developed in order to verify and relate the results of the principal approximations used in analytic analyses and to investigate the solutions and their growth-rate scalings over a large range of primary parameters which include parametric values applicable to the solar atmosphere. The computations cover the linear behavior for a variety of boundary conditions, emphasizing effects which differentiate magnetic tearing in astrophysical situations from that in laboratory devices. Eigenfunction profiles for long and short wavelengths are computed and the applicability of the 'constant psi' approximation is investigated. The growth rate is computed for values of the magnetic Reynolds number up to a trillion and of the dimensionless wavelength parameter down to 0.001. The analysis predicts significant effects due to differing values of the magnetic Reynolds number.

  9. CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces

    Science.gov (United States)

    2002-09-30

    CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces Alan W. Decho Department...TITLE AND SUBTITLE CoBOP: Microbial Biofilms: A Parameter Altering the Apparent Optical Properties of Sediments, Seagrasses and Surfaces 5a. CONTRACT...structures produced by bacteria. Their growth appears to depend on biofilm processes and light distributions ( photosynthesis ). Therefore, the data acquired

  10. Shifting the IGF-axis: An age-related decline in human tear IGF-1 correlates with clinical signs of dry eye.

    Science.gov (United States)

    Patel, Roshni; Zhu, Meifang; Robertson, Danielle M

    2018-02-06

    The human corneal epithelium expresses both the insulin-like growth factor type 1 receptor (IGF-1R) and the IGF-1R/insulin receptor (INSR) hybrid. Despite the previous identification of IGF-1 in human tear fluid, little is known regarding the regulation of IGF-1 in tear fluid and its role in corneal epithelial homeostasis. In the present study, we investigated the impact of biological parameters on the concentration of human tear levels of IGF-1. Tear levels of IGF-1 were measured in 41 healthy, human volunteers without any reported symptoms of dry eye. All volunteers underwent standard biomicroscopic examination of the cornea and tear film. In a subgroup of volunteers, corneal staining with sodium fluorescein, tear film break up time and tear production using a Schirmer's test strip were measured to assess clinical signs of dry eye. Tears were collected from the inferior tear meniscus using glass microcapillary tubes and IGF-1 levels were measured using a solid phase sandwich ELISA. Tear levels of IGF-1 were highest in young adults and significantly decreased in older adults (P = 0.003). There were no differences in tear IGF-1 between males and females (P = 0.628). Tear IGF-1 levels were correlated with tear film break up time (R = 0.738) and tear production (R = 0.826). These data indicate that there is a progressive decline in tear IGF-1 due to aging that is associated with clinical signs of dry eye. This effect is likely due to age-related changes in the lacrimal gland. Copyright © 2018 Elsevier Ltd. All rights reserved.

  11. A Simple Numerical Body Surface Mapping Parameter Signifies Successful Percutaneous Coronary Artery Intervention.

    Science.gov (United States)

    Simonyi, Gábor; Kirschner, Róbert; Szűcs, Endre; Préda, István; Duray, Gábor; Medvegy, Nóra; Horvath, Bálint; Medvegy, Mihály

    2016-03-01

    In coronary artery disease (CAD), body surface potential mapping (BSPM) may reveal minor electrical potential changes appearing in the depolarization phase even if pathological changes are absent on the conventional 12-lead ECG. We hypothesized that a simple BSPM parameter, Max/Min signifies successful percutaneous coronary intervention (PCI). Ninety-two adult Caucasian patients with stable CAD and positive exercise test underwent coronary angiography. Seventy patients (age, 59 ± 8; 46 males) were revascularized by PCI (left anterior descending [LAD] in 38, right [RCA] in 17 and left circumflex [LCX] coronary artery in 15). Control groups contained 22 patients (age, 60 ± 8; 14 males) without intervention and 35 healthy subjects (age, 58 ± 2; 15 males). Left ventricular ejection fraction (LVEF, transthoracic echocardiography) and Max/Min BSPM parameter (63-lead Montreal system) were evaluated before and 4-40 days following coronary angiography. Max/Min was defined by the ratio of the highest maximum to the deepest minimum potential of all leads recorded by BSPM. Before PCI, Max/Min value of patients with LAD lesion (0.83 [0.74; 0.93]) was significantly lower while that with RCA lesion (1.63 [1.35; 1.99]) was significantly higher than that of healthy group (1.01 [0.970; 1.13]) (P intervention. LVEF significantly increased (from 46.50% [43.00; 51.00] to 49.00% [46.00; 51.00]) only after LAD PCI. Max/Min parameter is suitable to follow patients after LAD and RCA PCI. © 2015 Wiley Periodicals, Inc.

  12. Tear and decohesion of bovine pericardial tissue.

    Science.gov (United States)

    Tobaruela, Almudena; Elices, Manuel; Bourges, Jean Yves; Rojo, Francisco Javier; Atienza, José Miguel; Guinea, Gustavo

    2016-10-01

    The aim of this study was to evaluate quantitatively the fracture-by tear and delamination-of bovine pericardium tissues which are usually employed for the manufacture of bioprosthetic valves. A large number of samples (77) were tested in root-to-apex and circumferential directions, according to a standardised tear test (ASTM D 1938). Before performing the tear test, some samples were subjected to 1000 cycles of fatigue to a maximum stress of 3MPa. Fracture toughness of tearing and delamination were computed by following a simple fracture model. The study showed significantly lower values of delamination toughness compared with tear delamination. Moreover, tear forces were different in each test direction, revealing a clear orthotropic behaviour. All these results, as well as the testing procedure, could be of value for future research in the physiological function of pericardium tissues and clinical applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Tearing mode saturation with finite pressure

    International Nuclear Information System (INIS)

    Lee, J.K.

    1988-01-01

    With finite pressure, the saturation of the current-driven tearing mode is obtained in three-dimensional nonlinear resistive magnetohydrodynamic simulations for Tokamak plasmas. To effectively focus on the tearing modes, the perturbed pressure effects are excluded while the finite equilibrium pressure effects are retained. With this model, the linear growth rates of the tearing modes are found to be very insensitive to the equilibrium pressure increase. The nonlinear aspects of the tearing modes, however, are found to be very sensitive to the pressure increase in that the saturation level of the nonlinear harmonics of the tearing modes increases monotonically with the pressure rise. The increased level is associated with enhanced tearing island sizes or increased stochastic magnetic field region. (author)

  14. MRI of meniscal bucket-handle tears

    Energy Technology Data Exchange (ETDEWEB)

    Magee, T.H.; Hinson, G.W. [Menorah Medical Center, Overland Park, KS (United States). Dept. of Radiology

    1998-09-01

    A meniscal bucket-handle tear is a tear with an attached fragment displaced from the meniscus of the knee joint. Low sensitivity of MRI for detection of bucket-handle tears (64% as compared with arthroscopy) has been reported previously. We report increased sensitivity for detecting bucket-handle tears with the use of coronal short tau inversion recovery (STIR) images. Results. By using four criteria for diagnosis of meniscal bucket-handle tears, our overall sensitivity compared with arthroscopy was 93% (28 of 30 meniscal bucket-handle tears seen at arthroscopy were detected by MRI). The meniscal fragment was well visualized in all 28 cases on coronal STIR images. The double posterior cruciate ligament sign was seen in 8 of 30 cases, the flipped meniscus was seen in 10 of 30 cases and a fragment in the intercondylar notch was seen in 18 of 30 cases. (orig.)

  15. Fourier-Domain Optical Coherence Tomography for Monitoring the Lower Tear Meniscus in Dry Eye after Acupuncture Treatment

    Directory of Open Access Journals (Sweden)

    Tong Lin

    2015-01-01

    Full Text Available Dry eye is highly prevalent and has a significant impact on quality of life. Acupuncture was found to be effective to treat dry eye. However, little was known about the effect of acupuncture on different subtypes of dry eye. The objective of this study was to investigate the applicability of tear meniscus assessment by Fourier-domain optical coherence tomography in the evaluation of acupuncture treatment response in dry eye patients and to explore the effect of acupuncture on different subtypes of dry eye compared with artificial tear treatment. A total of 108 dry eye patients were randomized into acupuncture or artificial tear group. Each group was divided into three subgroups including lipid tear deficiency (LTD, Sjögren syndrome dry eye (SSDE, and non-Sjögren syndrome dry eye (Non-SSDE for data analysis. After 4-week treatment, the low tear meniscus parameters including tear meniscus height (TMH, tear meniscus depth (TMD, and tear meniscus area (TMA in the acupuncture group increased significantly for the LTD and Non-SSDE subgroups compared with both the baseline and the control groups (all P values < 0.05, but not for the SSDE. Acupuncture provided a measurable improvement of the tear meniscus dimensions for the Non-SSDE and LTD patients, but not for the SSDE patients.

  16. The evaluation of central corneal thickness and intraocular pressure in conjunction with tear IGF-1 levels in patients with acromegaly.

    Science.gov (United States)

    Kan, Emrah; Kan, Elif K; Okuyucu, Ali

    2017-08-30

    To compare the central corneal thickness (CCT), intraocular pressure (IOP), and tear insulin-like growth factor 1 (IGF-1) levels between patients with acromegaly and a control group and to evaluate the possible effect of tear IGF-1 and duration of the disease on CCT and IOP. We included 31 patients with acromegaly (study group) and 40 age- and sex-matched controls in the study. Patients with acromegaly were divided into 2 subgroups based on disease status (active/inactive). All participants underwent complete ophthalmologic evaluation including CCT and IOP values. Basal tear samples were collected from both groups and tear IGF-1 levels were measured. The CCT, IOP, and tear IGF-1 levels were compared between groups and subgroups and the association between tear IGF-I levels and ocular parameters (CCT, IOP) and disease duration were also evaluated. Central corneal thickness, IOP, and tear IGF-1 levels did not show a significant difference between study and control groups. We also did not find a significant difference in terms of CCT, IOP, or tear IGF-1 levels between subgroups of patients. Correlation analysis did not show an association between the duration of disease and tear IGF-1 levels with CCT or IOP. There was no significant difference in tear IGF-1 levels between patients with acromegaly and controls. Additionally, there was no correlation between disease duration and tear IGF-1 levels with CCT or IOP levels. This lack of association may suggest that tear IGF-1 levels might not have an effect on CCT or IOP findings in patients with acromegaly.

  17. The tearing mode in the long wavelenght limit

    International Nuclear Information System (INIS)

    Paris, R.B.

    1981-06-01

    The value of the logarithmic derivative Δ' in the boundary layer for the plane symmetric resistive tearing mode is calculted analytically for arbitrary wavelength parameter α approximately<1. Its value is given. The familiar 'constant-psi' approximation corresponding to lambda approximately 0 is discussed. The analytic forms in the boundary layer of the normalized magnetic field and velocity perturbations psi and U are obtained

  18. Analysis of parameter and interaction between parameter of the microwave assisted transesterification process of coconut oil using response surface methodology

    Science.gov (United States)

    Hidayanti, Nur; Suryanto, A.; Qadariyah, L.; Prihatini, P.; Mahfud, Mahfud

    2015-12-01

    A simple batch process was designed for the transesterification of coconut oil to alkyl esters using microwave assisted method. The product with yield above 93.225% of alkyl ester is called the biodiesel fuel. Response surface methodology was used to design the experiment and obtain the maximum possible yield of biodiesel in the microwave-assisted reaction from coconut oil with KOH as the catalyst. The results showed that the time reaction and concentration of KOH catalyst have significant effects on yield of alkyl ester. Based on the response surface methodology using the selected operating conditions, the time of reaction and concentration of KOH catalyst in transesterification process were 150 second and 0.25%w/w, respectively. The largest predicted and experimental yield of alkyl esters (biodiesel) under the optimal conditions are 101.385% and 93.225%, respectively. Our findings confirmed the successful development of process for the transesterification reaction of coconut oil by microwave-assisted heating, which is effective and time-saving for alkyl ester production.

  19. Percentage Level of Tannin fur Rabbit for Leather Concerning Stitch Tearing Strength, Tearing Strength and Flexibility

    OpenAIRE

    Mustakim Mustakim; Aris Sri Widati; Lisa Purnaningtyas

    2012-01-01

    The purpose of this study was to find out the appropriate of tannin level for rabbit fur leather concerning stitch tearing strength, tearing strength, and flexibility. The result were expected to contribute good information for the society, leather craftsman, and further researchers about fur leather tanning especially rabbit fur leather with tannin concerning stitch tearing strength, tearing strength and flexibility. The material that used were 12 pieces of four months of rabbit skin. The re...

  20. Artificial tears potpourri: a literature review

    Science.gov (United States)

    Moshirfar, Majid; Pierson, Kasey; Hanamaikai, Kamalani; Santiago-Caban, Luis; Muthappan, Valliammai; Passi, Samuel F

    2014-01-01

    Numerous brands and types of artificial tears are available on the market for the treatment of dysfunctional tear syndrome. Past literature has focused on comparing the components of these products on patient’s clinical improvement. The wide array of products on the market presents challenges to both clinicians and patients when trying to choose between available tear replacement therapies. Different formulations affect patients based on etiology and severity of disease. In order to provide an unbiased comparison between available tear replacement therapies, we conducted a literature review of existing studies and National Institutes of Health clinical trials on commercially available, brand name artificial tears. Outcomes evaluated in each study, as well as the percent of patients showing clinical and symptomatic improvement, were analyzed. Fifty-one studies evaluating different brands of artificial tears, and their efficacy were identified. Out of the 51 studies, 18 were comparison studies testing brand name artificial tears directly against each other. Nearly all formulations of artificial tears provided significant benefit to patients with dysfunctional tear syndrome, but some proved superior to others. From the study data, a recommended treatment flowchart was derived. PMID:25114502

  1. Key parameters of the sediment surface morphodynamics in an estuary - An assessment of model solutions

    Science.gov (United States)

    Sampath, D. M. R.; Boski, T.

    2018-05-01

    Large-scale geomorphological evolution of an estuarine system was simulated by means of a hybrid estuarine sedimentation model (HESM) applied to the Guadiana Estuary, in Southwest Iberia. The model simulates the decadal-scale morphodynamics of the system under environmental forcing, using a set of analytical solutions to simplified equations of tidal wave propagation in shallow waters, constrained by empirical knowledge of estuarine sedimentary dynamics and topography. The key controlling parameters of the model are bed friction (f), current velocity power of the erosion rate function (N), and sea-level rise rate. An assessment of sensitivity of the simulated sediment surface elevation (SSE) change to these controlling parameters was performed. The model predicted the spatial differentiation of accretion and erosion, the latter especially marked in the mudflats within mean sea level and low tide level and accretion was mainly in a subtidal channel. The average SSE change mutually depended on both the friction coefficient and power of the current velocity. Analysis of the average annual SSE change suggests that the state of intertidal and subtidal compartments of the estuarine system vary differently according to the dominant processes (erosion and accretion). As the Guadiana estuarine system shows dominant erosional behaviour in the context of sea-level rise and sediment supply reduction after the closure of the Alqueva Dam, the most plausible sets of parameter values for the Guadiana Estuary are N = 1.8 and f = 0.8f0, or N = 2 and f = f0, where f0 is the empirically estimated value. For these sets of parameter values, the relative errors in SSE change did not exceed ±20% in 73% of simulation cells in the studied area. Such a limit of accuracy can be acceptable for an idealized modelling of coastal evolution in response to uncertain sea-level rise scenarios in the context of reduced sediment supply due to flow regulation. Therefore, the idealized but cost

  2. Novel Nano-Liposome Formulation for Dry Eyes with Components Similar to the Preocular Tear Film

    Directory of Open Access Journals (Sweden)

    Marta Vicario-de-la-Torre

    2018-04-01

    Full Text Available Dry eye is commonly treated with artificial tears; however, developing artificial tears similar to natural tears is difficult due to the complex nature of tears. We characterized and evaluated a novel artificial tear formulation with components similar to the lipid and aqueous constituents of natural tears. Nano-liposomes, composed in part of phosphatidylcholine, were dispersed in an aqueous solution of bioadhesive sodium hyaluronate. Liposome size, zeta potential, and physicochemical properties of the fresh and stored (4 °C liposomal formulation were analyzed. In vitro tolerance was tested using human corneal and conjunctival cell lines by exposures of 15 min to 4 h. The tolerance of the liposomal formulation was evaluated in animals (rabbits. The average liposome size was 186.3 ± 7.0 nm, and the zeta potential was negative. The osmolarity of the formulation was 198.6 ± 1.7 mOsm, with a surface tension of 36.5 ± 0.4 mN/m and viscosity of 3.05 ± 0.02 mPa·s. Viability values in the human corneal and conjunctival cell lines were always >80%, even after liposomal formulation storage for 8 weeks. Discomfort and clinical signs after instillation in rabbit eyes were absent. The new formulation, based on phosphatidylcholine-liposomes dispersed in sodium hyaluronate has suitable components and characteristics, including high in vitro cell viability and good in vivo tolerance, to serve as a tear substitute.

  3. Effects of amino acids enriched tears substitutes on the cornea of patients with dysfunctional tear syndrome.

    Science.gov (United States)

    Aragona, Pasquale; Rania, Laura; Roszkowska, Anna M; Spinella, Rosaria; Postorino, Elisa; Puzzolo, Domenico; Micali, Antonio

    2013-09-01

    To evaluate the effect of aminoacid enriched artificial tears on the ocular surface of patients with dysfunctional tear syndrome (DTS). Forty patients were divided into two groups: group 1 treated for 90 days with sodium hyaluronate (SH) 0.15% 1 drop × 5 times/day; group 2 treated for 90 days with SH 0.15% + aminoacids mixture 1 drop × 5 times/day. Symptom score questionnaire, tear break-up time (TBUT), corneal fluorescein stain, Shirmer's I test and confocal microscopy were performed at baseline and after 30 and 90 days. Confocal images underwent morphometric analysis. Both treatments improved symptoms after 1 month. Group 2 patients showed at 1 month an improvement of TBUT and corneal stain, maintained throughout the study. Also Shirmer's I test improved after 3 months. In group 1, an improvement of TBUT and corneal stain was observed after 3 months. The morphometric analysis of confocal images demonstrated at month 1 an improvement of nerve tortuosity in group 2; after 3 months both groups showed a significant improvement versus baseline. The epithelium showed, in both groups, a reduction in hyperreflective large cells starting from 1 month; the area of the cells was significantly reduced after 3 months, with a significant higher reduction in group 2. The perineural stromal opacity was significantly increased after 3 months, particularly in group 2. This is the first study addressing corneal changes after amino acids administration in a DTS population. The treatment with amino acids enriched SH can be considered a useful tool in the treatment of DTS. © 2013 The Authors Acta Ophthalmologica © 2013 Acta Ophthalmologica Scandinavica Foundation. Published by Blackwell Publishing Ltd.

  4. Stability of multihelical tearing modes in shaped tokamaks

    International Nuclear Information System (INIS)

    Kerner, W.; Tasso, H.

    1982-03-01

    The stability of multihelical tearing modes in tokamaks with shaped cross-sections is determined numerically. The method allows inclusion of a large number of singular surfaces resolved with high accuracy. Poloidal and radial couplings are discussed and the convergence is well understood. High poloidal m number modes are found to be unstable for typical equilibria. Completely stable current distributions have been constructed for D-shaped plasmas. (orig.)

  5. 3D Strain Modelling of Tear Fault Analogues

    Science.gov (United States)

    Hindle, D.; Vietor, T.

    2005-12-01

    Tear faults can be described as vertical discontinuities, with near fault parallel displacements terminating on some sort of shallow detachment. As such, they are difficult to study in "cross section" i.e. 2 dimensions as is often the case for fold-thrust systems. Hence, little attempt has been made to model the evolution of strain around tear faults and the processes of strain localisation in such structures due to the necessity of describing these systems in 3 dimensions and the problems this poses for both numerical and analogue modelling. Field studies suggest that strain in such regions can be distributed across broad zones on minor tear systems, which are often not easily mappable. Such strain is probably assumed to be due to distributed strain and to displacement gradients which are themselves necessary for the initiation of the tear itself. We present a numerical study of the effects of a sharp, basal discontinutiy parallel to the transport direction in a shortening wedge of material. The discontinuity is represented by two adjacent basal surfaces with strongly contrasting (0.5 and 0.05) friction coefficient. The material is modelled using PFC3D distinct element software for simulating granular material, whose properties are chosen to simulate upper crustal, sedimentary rock. The model geometry is a rectangular bounding box, 2km x 1km, and 0.35-0.5km deep, with a single, driving wall of constant velocity. We show the evolution of strain in the model in horizontal and vertical sections, and interpret strain localization as showing the spontaneous development of tear fault like features. The strain field in the model is asymmetrical, rotated towards the strong side of the model. Strain increments seem to oscillate in time, suggesting achievement of a steady state. We also note that our model cannot be treated as a critical wedge, since the 3rd dimension and the lateral variations of strength rule out this type of 2D approximation.

  6. A new method for tear film stability analysis using videokeratography.

    Science.gov (United States)

    Goto, Tomoko; Zheng, Xiaodong; Klyce, Stephen D; Kataoka, Hisashi; Uno, Toshihiko; Karon, Mike; Tatematsu, Yoshiyuki; Bessyo, Takeo; Tsubota, Kazuo; Ohashi, Yuichi

    2003-05-01

    To report a new tear film stability analysis system using videokeratography. Observational case series. New videokeratography software for TMS-2N (topographic modeling system; TOMEY Corporation, Nagoya, Japan) was developed that can automatically capture consecutive corneal surface images every second for 10 seconds. Forty-eight adult volunteers (80 eyes) were recruited for this study, and all subjects were examined with the new system. Corneal topographs were analyzed for tear breakup time (TMS-BUT) and the ratio of breakup area to entire color-code area (TMS-BUA) was calculated. Routine methods for tear film breakup time evaluation using slit-lamp microscope and fluorescence staining (SLE-BUT) were performed for comparison purposes. Regressive correlations of TMS-BUT or TMS-BUA with SLE-BUT were analyzed. Based on SLE results, subjects were separated into two groups with normal and short BUT, respectively. TMS-BUT and TMS-BUA were compared with SLE-BUT data with regard to the sensitivity and specificity of evaluation of dry eye symptoms. Topographic modeling system-tear breakup time (TMS-BUT) had a positive correlation with SLE-BUT (R = 0.7219, P TMS-BUA showed a negative correlation (R = 0.6317, P TMS-BUT, 9 (81.82%) of which were associated with dry eye symptoms. The sensitivities of TMS-BUT and TMS-BUA were 97.5% and 95%, respectively, significantly higher than that of SLE-BUT (75%), with P =.008 and 0.01, respectively. Topographic modeling system-BUT and TMS-BUA displayed a similar rate of specificity in comparison with SLE-BUT. This new videokeratography system is a noninvasive and objective method with increased sensitivity for tear film stability analysis.

  7. Parameters effects study on pulse laser for the generation of surface acoustic waves in human skin detection applications

    Science.gov (United States)

    Li, Tingting; Fu, Xing; Dorantes-Gonzalez, Dante J.; Chen, Kun; Li, Yanning; Wu, Sen

    2015-10-01

    Laser-induced Surface Acoustic Waves (LSAWs) has been promisingly and widely used in recent years due to its rapid, high accuracy and non-contact evaluation potential of layered and thin film materials. For now, researchers have applied this technology on the characterization of materials' physical parameters, like Young's Modulus, density, and Poisson's ratio; or mechanical changes such as surface cracks and skin feature like a melanoma. While so far, little research has been done on providing practical guidelines on pulse laser parameters to best generate SAWs. In this paper finite element simulations of the thermos-elastic process based on human skin model for the generation of LSAWs were conducted to give the effects of pulse laser parameters have on the generated SAWs. And recommendations on the parameters to generate strong SAWs for detection and surface characterization without cause any damage to skin are given.

  8. Effect of Surface Tension Anisotropy and Welding Parameters on Initial Instability Dynamics During Solidification: A Phase-Field Study

    Science.gov (United States)

    Yu, Fengyi; Wei, Yanhong

    2018-05-01

    The effects of surface tension anisotropy and welding parameters on initial instability dynamics during gas tungsten arc welding of an Al-alloy are investigated by a quantitative phase-field model. The results show that the surface tension anisotropy and welding parameters affect the initial instability dynamics in different ways during welding. The surface tension anisotropy does not influence the solute diffusion process but does affect the stability of the solid/liquid interface during solidification. The welding parameters affect the initial instability dynamics by varying the growth rate and thermal gradient. The incubation time decreases, and the initial wavelength remains stable as the welding speed increases. When welding power increases, the incubation time increases and the initial wavelength slightly increases. Experiments were performed for the same set of welding parameters used in modeling, and the results of the experiments and simulations were in good agreement.

  9. Transient Tear Film Dysfunction after Cataract Surgery in Diabetic Patients.

    Directory of Open Access Journals (Sweden)

    Donghong Jiang

    Full Text Available Diabetes mellitus is an increasingly common systemic disease. Many diabetic patients seek cataract surgery for a better visual acuity. Unlike in the general population, the influence of cataract surgery on tear film function in diabetic patients remains elusive. The aim of this study was to evaluate the tear function in diabetic and nondiabetic patients following cataract surgery.In this prospective, interventional case series, 174 diabetic patients without dry eye syndrome (DES and 474 age-matched nondiabetic patients as control who underwent phacoemulsification were enrolled at two different eye centers between January 2011 and January 2013. Patients were followed up at baseline and at 7 days, 1 month, and 3 months postoperatively. Ocular symptom scores (Ocular Surface Disease Index, OSDI and tear film function including tear film stability (tear film break-up time, TBUT, corneal epithelium integrity (corneal fluorescein staining, CFS, and tear secretion (Schirmer's I test, SIT were evaluated.In total, 83.9% of the diabetic patients (146 cases with 185 eyes and 89.0% of the nondiabetic patients (422 cases with 463 eyes completed all check-ups after the interventions (P = 0.095. The incidence of DES was 17.1% in the diabetic patients and 8.1% in the nondiabetic patients at 7 days after cataract surgery. In the diabetic patients, the incidence of DES remained 4.8% at 1 month postoperatively and decreased to zero at 3 months after surgery. No DES was diagnosed in nondiabetic patients at either the 1-month or 3-month follow-up. Compared with the baseline, the diabetic patients had worse symptom scores and lower TBUT values at 7 days and 1 month but not at 3 months postoperatively. In the nondiabetic patients, symptom scores and TBUT values had returned to preoperative levels at 1-month check-up. CFS scores and SIT values did not change significantly postoperatively in either group (P = 0.916 and P = 0.964, respectively.Diabetic patients undergoing

  10. Analysis of process parameters in surface grinding using single objective Taguchi and multi-objective grey relational grade

    Directory of Open Access Journals (Sweden)

    Prashant J. Patil

    2016-09-01

    Full Text Available Close tolerance and good surface finish are achieved by means of grinding process. This study was carried out for multi-objective optimization of MQL grinding process parameters. Water based Al2O3 and CuO nanofluids of various concentrations are used as lubricant for MQL system. Grinding experiments were carried out on instrumented surface grinding machine. For experimentation purpose Taguchi's method was used. Important process parameters that affect the G ratio and surface finish in MQL grinding are depth of cut, type of lubricant, feed rate, grinding wheel speed, coolant flow rate, and nanoparticle size. Grinding performance was calculated by the measurement G ratio and surface finish. For improvement of grinding process a multi-objective process parameter optimization is performed by use of Taguchi based grey relational analysis. To identify most significant factor of process analysis of variance (ANOVA has been used.

  11. Optimization of extraction parameters of pentacyclic triterpenoids from Swertia chirata stem using response surface methodology.

    Science.gov (United States)

    Pandey, Devendra Kumar; Kaur, Prabhjot

    2018-03-01

    In the present investigation, pentacyclic triterpenoids were extracted from different parts of Swertia chirata by solid-liquid reflux extraction methods. The total pentacyclic triterpenoids (UA, OA, and BA) in extracted samples were determined by HPTLC method. Preliminary studies showed that stem part contains the maximum pentacyclic triterpenoid and was chosen for further studies. Response surface methodology (RSM) has been employed successfully by solid-liquid reflux extraction methods for the optimization of different extraction variables viz., temperature ( X 1 35-70 °C), extraction time ( X 2 30-60 min), solvent composition ( X 3 20-80%), solvent-to-solid ratio ( X 4 30-60 mlg -1 ), and particle size ( X 5 3-6 mm) on maximum recovery of triterpenoid from stem parts of Swertia chirata . A Plackett-Burman design has been used initially to screen out the three extraction factors viz., particle size, temperature, and solvent composition on yield of triterpenoid. Moreover, central composite design (CCD) was implemented to optimize the significant extraction parameters for maximum triterpenoid yield. Three extraction parameters viz., mean particle size (3 mm), temperature (65 °C), and methanol-ethyl acetate solvent composition (45%) can be considered as significant for the better yield of triterpenoid A second-order polynomial model satisfactorily fitted the experimental data with the R 2 values of 0.98 for the triterpenoid yield ( p  < 0.001), implying good agreement between the experimental triterpenoid yield (3.71%) to the predicted value (3.79%).

  12. Multi-parameter Full-waveform Inversion for Acoustic VTI Medium with Surface Seismic Data

    Science.gov (United States)

    Cheng, X.; Jiao, K.; Sun, D.; Huang, W.; Vigh, D.

    2013-12-01

    Full-waveform Inversion (FWI) attracts wide attention recently in oil and gas industry as a new promising tool for high resolution subsurface velocity model building. While the traditional common image point gather based tomography method aims to focus post-migrated data in depth domain, FWI aims to directly fit the observed seismic waveform in either time or frequency domain. The inversion is performed iteratively by updating the velocity fields to reduce the difference between the observed and the simulated data. It has been shown the inversion is very sensitive to the starting velocity fields, and data with long offsets and low frequencies is crucial for the success of FWI to overcome this sensitivity. Considering the importance of data with long offsets and low frequencies, in most geologic environment, anisotropy is an unavoidable topic for FWI especially at long offsets, since anisotropy tends to have more pronounced effects on waves traveled for a great distance. In VTI medium, this means more horizontal velocity will be registered in middle-to-long offset data, while more vertical velocity will be registered in near-to-middle offset data. Up to date, most of real world applications of FWI still remain in isotropic medium, and only a few studies have been shown to account for anisotropy. And most of those studies only account for anisotropy in waveform simulation, but not invert for those anisotropy fields. Multi-parameter inversion for anisotropy fields, even in VTI medium, remains as a hot topic in the field. In this study, we develop a strategy for multi-parameter FWI for acoustic VTI medium with surface seismic data. Because surface seismic data is insensitivity to the delta fields, we decide to hold the delta fields unchanged during our inversion, and invert only for vertical velocity and epsilon fields. Through parameterization analysis and synthetic tests, we find that it is more feasible to invert for the parameterization as vertical and horizontal

  13. Crack Tip Flipping under Mode I Tearing: Investigated by X-Ray Tomography

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Gundlach, Carsten

    2017-01-01

    The fracture surface morphology that results from mode I tearing of ductile plate metals depends heavily on both the elastic-plastic material properties and the microstructure. Severe tunneling of the advancing crack tip (resulting in cup-cup, or bath-tub like fracture surfaces) can take place...... in a range of materials, often of low strength, while tearing of high strength metals typically progress by the shear band failure mechanism (slanting). In reality, however, most fracture surfaces display a mixture of morphologies. For example, slant crack propagation can be accompanied by large shear lips...... near the outer free plate surface or a complete shear band switch - seemingly distributed randomly on the fracture surface. The occasionally observed shear band switch of mode I slant cracks, related to ductile plate tearing, is far from random as the crack can flip systematically from one side...

  14. Tear Mediators in Corneal Ectatic Disorders.

    Directory of Open Access Journals (Sweden)

    Dorottya Pásztor

    Full Text Available To compare the concentrations of 11 tear mediators in order to reveal the biochemical difference between pellucid marginal degeneration (PMD and keratoconus (KC.We have designed a cross-sectional study in which patients with corneal ectasia based on slit-lamp biomicroscopy and Pentacam HR (keratometry values (K1, K2, Kmax, astigmatism, minimal radius of curvature (Rmin, corneal thickness (Apex and Min, indices (surface variation, vertical asymmetry, keratoconus, central keratoconus, height asymmetry and decentration were enrolled. Eyes of keratoconic patients were similar to the PMD patients in age and severity (K2, Kmax and Rmin. Non-stimulated tear samples were collected from nine eyes of seven PMD patients, 55 eyes of 55 KC patients and 24 eyes of 24 healthy controls. The mediators' (interleukin -6, -10, chemokine ligand 5, -8, -10, matrix metalloproteinase (MMP -9, -13, tissue inhibitor of metalloproteinases (TIMP-1, tissue plasminogen activator, plasminogen activator inhibitor, nerve growth factor concentrations were measured using Cytometric Bead Array.MMP-9 was the only mediator which presented relevant variances between the two patient groups (p = 0.005. The ratios of MMP-9 and TIMP-1 were 2.45, 0.40 and 0.23 in PMD, KC and the controls, respectively.As far as we are aware, this is the first study that aims to reveal the biochemical differences between PMD and KC. Further studies of biomarkers to investigate the precise role of these mediators need to be defined, and it is important to confirm the observed changes in a larger study to gain further insights into the molecular alterations in PMD.

  15. Tear film stability analysis system: introducing a new application for videokeratography.

    Science.gov (United States)

    Goto, Tomoko; Zheng, Xiaodong; Okamoto, Shigeki; Ohashi, Yuichi

    2004-11-01

    To review our previous studies regarding the development of a tear stability analysis system (TSAS) using videokeratography and the clinical application of TSAS for evaluation of tear film stability in patients subject to laser in situ keratomileusis (LASIK). New software, namely TSAS, was developed for the videokeratography system TMS-2N (topographic modeling system). TSAS automatically captures consecutive corneal surface images every second for 10 seconds. Corneal topographs were analyzed for tear breakup time (TMS-BUT) and tear breakup area (TMS-BUA, the ratio of breakup area to entire color-code area). First, we recruited volunteers to test the sensitivity and specificity of this new system in comparison with the routine method for tear stability analysis, tear film breakup time evaluation by slit-lamp microscope (SLE-BUT), with fluorescence staining. Second, we investigated the practicability of TSAS in dynamic evaluation of tear film stability before and after LASIK. TMS-BUT had a positive correlation with SLE-BUT, whereas TMS-BUA showed a negative correlation. Although they showed similar rates of specificity as SLE-BUT, the sensitivity rates of TMS-BUT and TMS-BUA were 97.5% and 95%, respectively, significantly higher than that of SLE-BUT (75%). The study on patients subject to LASIK showed that tear film stability significantly decreased during the early time period following LASIK and resolved at 6 months after surgery. Eyes that had abnormal TSAS evaluation tended to have higher risk of developing superficial punctuate keratitis and dry eye symptoms after LASIK, and their responses to treatment were slow. TSAS is a noninvasive and objective method with higher sensitivity for tear film stability analysis than SLE-BUT.

  16. [The incidence of retinal tears in patients with posterior vitreous detachment].

    Science.gov (United States)

    Karaman, Ksenija; Gverović-Antunica, Antonela; Bućan, Kajo; Znaor, Ljubo; Bulović, Dijana; Skelin, Sinia

    2006-01-01

    Posterior vitreous detachment (PVD) is a common finding in older patients, characterized by detachment of the posterior hyaloid membrane (PHM) from the retinal surface. The detachment of PHM normally occurs without complications, however, one has to be aware that retinal tear is its most common complication. The aim of the study was to determine the incidence of retinal tears in eyes with PVD. A series of 40 patients (70 eyes) with PVD were included in this retrospective study. Eyes with a history of ocular trauma, surgery or intraocular inflammation were excluded. Patient charts were reviewed to collect the following information: age, sex, profession, type and duration of symptoms, best corrected visual acuity, refractive status, prior ocular disease, coincidental retinal pathology-lattice degeneration, number, type and location of retinal tears and treatment. Statistical analysis was done with the SPSS 11.0.3 software (SPSS Inc., USA). Besides descriptive statistics, Student's t-test and chi2-test were used. Among all study eyes with PVD, 34 (48.6%) were myopic, 24 (34.3%) hypermetropic and 12 (17.1%) emetropic; statistical analysis showed a significant difference (chi2 = 10.40, df=2, p lattice malignant degeneration of peripheral retinal was diagnosed. Thorough examination of the fundus periphery revealed 16 (22.8%) eyes with PVD were found to have retinal tears, 11 (15.7%) had only one retinal tear and 5 (7.1%) two retinal tears. All retinal tears were treated with argon laser photocoagulation. Superotemporal eye quadrant was the most common localization of retinal tears (56.25%). These results indicate that thorough fundus periphery examination should be done in all patients with PVD because it can cause rather rarely though retinal tears that represent a potentially sight threatening condition.

  17. Application of Response Surface Methodology (RSM for Optimization of Operating Parameters and Performance Evaluation of Cooling Tower Cold Water Temperature

    Directory of Open Access Journals (Sweden)

    Ramkumar RAMAKRISHNAN

    2012-01-01

    Full Text Available The performance of a cooling tower was analyzed with various operating parameters tofind the minimum cold water temperature. In this study, optimization of operating parameters wasinvestigated. An experimental design was carried out based on central composite design (CCD withresponse surface methodology (RSM. This paper presents optimum operating parameters and theminimum cold water temperature using the RSM method. The RSM was used to evaluate the effectsof operating variables and their interaction towards the attainment of their optimum conditions.Based on the analysis, air flow, hot water temperature and packing height were high significanteffect on cold water temperature. The optimum operating parameters were predicted using the RSMmethod and confirmed through experiment.

  18. Evaluation of The Effects of Cutting Parameters On The Surface Roughness During The Turning of Hadfield Steel With Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Ergün EKİCİ

    2014-12-01

    Full Text Available Hadfield steel (X120Mn12 is widely used in the engineering applications due to its excellent wear resistance. In this study, the effects of the cutting parameters on the surface roughness were investigated in relation to the lathe process carried out on Hadfield steel. The experiments were conducted at a cutting speed of 80, 110, 140 m/min, feed rate of 0.2, 0.3, 0.4 mm/rev and depth of cut 0.2, 0.4, 0.6 mm, using coated carbide tools. Regarding the evaluation of the machinability of Hadfield steel, a model was formed utilizing the response surface method (RSM. For the determination of the effects of the cutting parameters on the surface roughness, the central composite design (CCD and variance analysis (ANOVA were used. By means of the model formed as a result of the experimental study, it was demonstrated that among the cutting parameters, the feed rate is the most effective parameter on the surface roughness, with a contribution ratio of 90.28%. It was determined that the surface roughness increases with increasing feed rate. With respect to the effect on the surface roughness, the feed rate was followed by the cutting speed with a contribution ratio of 3.1% and the cutting depth with a contribution ratio of 1.7%.

  19. Computational modeling of neoclassical and resistive MHD tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Gianakon, T.A.; Hegna, C.C.; Callen, J.D.

    1996-01-01

    Numerical studies of the nonlinear evolution of MHD-type tearing modes in three-dimensional toroidal geometry with neoclassical effects are presented. The inclusion of neoclassical physics introduces an additional free-energy source for the nonlinear formation of magnetic islands through the effects of a bootstrap current in Ohm's law. The neoclassical tearing mode is demonstrated to be destabilized in plasmas which are otherwise Δ' stable, albeit once an island width threshold is exceeded. The plasma pressure dynamics and neoclassical tearing growth is shown to be sensitive to the choice of the ratio of the parallel to perpendicular diffusivity (Χ parallel/Χ perpendicular). The study is completed with a demonstration and theoretical comparison of the threshold for single helicity neoclassical MHD tearing modes, which is described based on parameter scans of the local pressure gradient, the ratio of perpendicular to parallel pressure diffusivities Χ perpendicular/Χ parallel, and the magnitude of an initial seed magnetic perturbation

  20. Comparison between numerical and analytical results on the required rf current for stabilizing neoclassical tearing modes

    Science.gov (United States)

    Wang, Xiaojing; Yu, Qingquan; Zhang, Xiaodong; Zhang, Yang; Zhu, Sizheng; Wang, Xiaoguang; Wu, Bin

    2018-04-01

    Numerical studies on the stabilization of neoclassical tearing modes (NTMs) by electron cyclotron current drive (ECCD) have been carried out based on reduced MHD equations, focusing on the amount of the required driven current for mode stabilization and the comparison with analytical results. The dependence of the minimum driven current required for NTM stabilization on some parameters, including the bootstrap current density, radial width of the driven current, radial deviation of the driven current from the resonant surface, and the island width when applying ECCD, are studied. By fitting the numerical results, simple expressions for these dependences are obtained. Analysis based on the modified Rutherford equation (MRE) has also been carried out, and the corresponding results have the same trend as numerical ones, while a quantitative difference between them exists. This difference becomes smaller when the applied radio frequency (rf) current is smaller.

  1. The effects of processing parameters on the properties of micro-scale porous surface for a micro-channel reactor

    International Nuclear Information System (INIS)

    Feng, Yanbing; Mei, Deqing; Qian, Miao; Yi, Zoudongyi; Chen, Zichen

    2017-01-01

    To improve the performance of hydrogen production via a microchannel reactor with a porous surface, the process of layered powder sintering and dissolution method is optimized, and the effects of processing parameters on the morphological and mechanical properties of the porous surface structure are studied. Based on the preliminary experiments, three key parameters in the process are the size of the NaCl particle, the compaction pressure, and the sintering temperature. Besides, the porous surface structures are evaluated by the specific surface area and compression strength to optimize the influencing variables. Results show that the specific surface area of porous surface structure is determined mainly by the size of NaCl particle, while the pressure and temperature have little influence unexpectedly within the range of experimental condition. With the increase of temperature and pressure, the compression strength will be enhanced, but the increase of the size of NaCl particles will cause the decrease of compression strength. The optimum compaction pressure, sintering temperature, and size of the NaCl particle are obtained respectively. Finally, the optimum parameters have been used to manufacture the micro-channel catalyst support with a porous surface, and its hydrogen production can be maximumly enhanced by 90% compared with the surface fabricated with NaCl particles of 125–150 µ m. (paper)

  2. A review on hot tearing of magnesium alloys

    Directory of Open Access Journals (Sweden)

    Jiangfeng Song

    2016-09-01

    Full Text Available Hot tearing is often a major casting defect in magnesium alloys and has a significant impact on the quality of their casting products. Hot tearing of magnesium alloys is a complex solidification phenomenon which is still not fully understood, it is of great importance to investigate the hot tearing behaviour of magnesium alloys. This review attempts to summarize the investigations on hot tearing of magnesium alloys over the past decades. The hot tearing criteria including recently developed Kou's criterion are summarized and compared. The numeric simulation and assessing methods of hot tearing, factors influencing hot tearing, and hot tearing susceptibility (HTS of magnesium alloys are discussed.

  3. Optimization of Extraction Parameters of Phenolic Compounds from Sarcopoterium spinosum Leaves by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Ceren Sunguc

    2017-07-01

    Full Text Available The shrublands are very common in Urla-Çeşme-Karaburun peninsula located in the western point of Turkey. Prickly shrubby burnet (Sarcopoterium spinosum L. is one of the common weed which has intensive thorns making its consumption for the local domestic animals. However, Sarcopoterium spinosum is a valuable and common medicinal plant in the Mediterranean region. Crude extract of S. spinosum leaves exhibited higher antioxidant activity, as 3143.5± 238.5 µM TEAC (Trolox Equivalent Antioxidant Capacity/g dry weight (DW, when compared to other medicinal plants found in the literature. The aim of this study was to determine the effect of extraction parameters on the content and biological activity of the extract by response surface methodology (RSM as well as to identify its major compounds. High Performance Liquid Chromatography (HPLC was employed to investigate the phenolic content of S. spinosum extract. The composition of the phenolic contents including hyperoside and isoquercetin, the latter being the major component, in S. spinosum extract has been shown for the first time by HPLC. Antimicrobial activity of S. spinosum extract, identified by minimum inhibition concentration (MIC assay, indicated that the crude extract had antifungal activity against Candida albicans.

  4. Reliability of surface electromyography timing parameters in gait in cervical spondylotic myelopathy.

    LENUS (Irish Health Repository)

    Malone, Ailish

    2012-02-01

    The aims of this study were to validate a computerised method to detect muscle activity from surface electromyography (SEMG) signals in gait in patients with cervical spondylotic myelopathy (CSM), and to evaluate the test-retest reliability of the activation times designated by this method. SEMG signals were recorded from rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG), during gait in 12 participants with CSM on two separate test days. Four computerised activity detection methods, based on the Teager-Kaiser Energy Operator (TKEO), were applied to a subset of signals and compared to visual interpretation of muscle activation. The most accurate method was then applied to all signals for evaluation of test-retest reliability. A detection method based on a combined slope and amplitude threshold showed the highest agreement (87.5%) with visual interpretation. With respect to reliability, the standard error of measurement (SEM) of the timing of RF, TA and MG between test days was 5.5% stride duration or less, while the SEM of BF was 9.4%. The timing parameters of RF, TA and MG designated by this method were considered sufficiently reliable for use in clinical practice, however the reliability of BF was questionable.

  5. MRI in diagnosing partial thickness tears of the rotator cuff

    International Nuclear Information System (INIS)

    Ogawa, Takeshi

    2000-01-01

    In this study 270 patients who had been treated for 10 years and had suspected rupture of the tendon and complete or partial thickness tears of the rotator cuff were diagnosed. Among these patients, MRI images in 50 cases were investigated to establish the diagnostic criteria for partial thickness tears of the rotator cuff. The rupture sites included the bursal surface in 15 shoulders, the articular surface in 30 shoulders, complicated cases of both surfaces in five shoulders with no intrasubstance. As for the imaging method, T2-weighted images were employed and the oblique coronary section, which is parallel to the scapula, was used as a imaging plane. From the results of the variation of the MRI signal intensity in the tendon, it was found that the signal intensity increased to 80% in the rupture of the bursal surface and 93.3% in the rupture of the articular surface. As for sites where the signals in the tendon increased, these were found at the bursal side in 83.3% of rupture at the bursal surface, and at the articular side in 100% of rupture at the articular surface. From these findings, the MRI-diagnostic criteria of partial thickness tears of the rotator cuff was defined as those cases which show a localized increase in signal intensity on the oblique coronary surface of T2 weighted images, but not in whole layers of the tendon. A high diagnostic rate with these criteria could be obtained with a sensitivity of 82.0%, specificity 90.9%, accuracy 84.7%, and positive predictive value 95.3%. (author)

  6. The social impact of emotional tears

    NARCIS (Netherlands)

    Vingerhoets, A.J.J.M.; van de Ven, N.; van der Velden, Y.

    2016-01-01

    The question what specific functions the production of emotional tears fulfills has received only limited attention of behavioral scientists. We report the results of two studies on the social impact of emotional tears. In Study 1 (96 Dutch females), perceived helplessness and felt connectedness

  7. Detecting meniscal tears in primary care

    NARCIS (Netherlands)

    Snoeker, B.A.M.

    2017-01-01

    Although meniscal tears are a very common phenomenon uncertainty exists about the diagnosis and treatment of meniscal tears in primary care. This thesis aims to provide evidence for general practitioners and physical therapists regarding the diagnosis and management of patients with a suspected

  8. Increasing the Tokamak Pressure Limit: Tearing Mode Experiments in DIII-D

    International Nuclear Information System (INIS)

    La Haye, R.J.

    2005-01-01

    Since its reconfiguration in 1986, DIII-D has performed a number of experiments involving resistive magnetohydrodynamic (MHD) stability. These were and are directed to understand the conditions in which confinement and beta reducing tearing mode islands form, how to avoid them, and if unavoidable, how to stabilize them. Coils for correction of toroidal nonaxisymmetry have been developed to avoid error field locked mode islands. Basic classical tearing mode stability physics has been confirmed with a state-of-the-art ensemble of profile diagnostics, MHD equilibrium reconstruction, and stability code analysis. Neoclassical tearing mode thresholds and seeding are now much better understood with future large higher field devices expected to be 'metastable'. DIII-D is the leader in sophisticated real-time alignment of stabilizing electron cyclotron current drive on otherwise unstable rational surfaces. In all, DIII-D experiments are showing how higher stable beta with good confinement can be maintained without tearing mode islands limiting the plasma pressure

  9. Effects of cutting parameters and machining environments on surface roughness in hard turning using design of experiment

    Science.gov (United States)

    Mia, Mozammel; Bashir, Mahmood Al; Dhar, Nikhil Ranjan

    2016-07-01

    Hard turning is gradually replacing the time consuming conventional turning process, which is typically followed by grinding, by producing surface quality compatible to grinding. The hard turned surface roughness depends on the cutting parameters, machining environments and tool insert configurations. In this article the variation of the surface roughness of the produced surfaces with the changes in tool insert configuration, use of coolant and different cutting parameters (cutting speed, feed rate) has been investigated. This investigation was performed in machining AISI 1060 steel, hardened to 56 HRC by heat treatment, using coated carbide inserts under two different machining environments. The depth of cut, fluid pressure and material hardness were kept constant. The Design of Experiment (DOE) was performed to determine the number and combination sets of different cutting parameters. A full factorial analysis has been performed to examine the effect of main factors as well as interaction effect of factors on surface roughness. A statistical analysis of variance (ANOVA) was employed to determine the combined effect of cutting parameters, environment and tool configuration. The result of this analysis reveals that environment has the most significant impact on surface roughness followed by feed rate and tool configuration respectively.

  10. Changes in corneal sensation, epithelial damage, and tear function after descemet stripping automated endothelial keratoplasty.

    Science.gov (United States)

    Hirayama, Yumiko; Satake, Yoshiyuki; Hirayama, Masatoshi; Shimazaki-Den, Seika; Konomi, Kenji; Shimazaki, Jun

    2013-09-01

    To study the ocular surface changes in eyes after Descemet stripping automated endothelial keratoplasty (DSAEK) compared with those after penetrating keratoplasty (PKP). This prospective study compared the changes in 31 eyes of 28 patients who underwent DSAEK (DSAEK group) with those in 15 disease-matched eyes of 15 patients who underwent PKP (PKP group). Corneal epithelial integrity was evaluated using a fluorescein staining score. Corneal sensation was measured with a Cochet-Bonnet esthesiometer. Tear function was evaluated using the Schirmer test, tear clearance test, tear function index, and tear break-up time. The postoperative fluorescein staining score was significantly higher in the PKP group than in the DSAEK group (P = 0.02). Postoperative corneal sensation was significantly better in the DSAEK group than in the PKP group (P sensation after DSAEK was significantly better than the preoperative value (P = 0.02). There were no statistically significant changes in the Schirmer test, tear clearance test, tear function index, or break-up time before and after the surgery in both the DSAEK and PKP groups. No significant differences were observed between the DSAEK and PKP groups after the surgery. Corneal sensation was preserved, and epithelial damage was less severe after DSAEK compared with PKP. Preservation of corneal sensation may contribute to the early recovery of visual function and long-term maintenance of ocular surface health after DSAEK.

  11. Deltoid muscle and tendon tears in patients with chronic rotator cuff tears

    International Nuclear Information System (INIS)

    Ilaslan, Hakan; Recht, Michael P.; Iannotti, Joseph P.

    2007-01-01

    To describe the magnetic resonance imaging (MRI) appearances of tears of the deltoid muscle and tendon in patients with rotator cuff tears and without a prior history of shoulder surgery. Deltoid tears diagnosed on MR examinations were prospectively recorded between February 2003 through June 2004. The images of these patients were then retrospectively reviewed to determine the location of the deltoid tear, the presence of rotator cuff tears, tendon retraction, muscle atrophy, degree of humeral head subluxation, bony erosive changes involving the undersurface of the acromion, and the presence of edema or fluid-like signal intensity in the deltoid muscle and overlying subcutaneous tissues. There were 24 (0.3%) patients with deltoid tears; nine men and 15 women. The age range was 54 to 87 (average 73) years. The right side was involved in 20 cases, and the left in four cases. Fifteen patients had full thickness and nine had partial thickness tears of the deltoid. Shoulder pain was the most common presenting symptom. The physical examination revealed a defect in the region of the deltoid in two patients. Nineteen patients had tears in the muscle belly near the musculotendinous junction, and five had avulsion of the tendon from the acromial origin. Full thickness rotator cuff tears were present in all of the patients, and 22 patients had associated muscle atrophy. Subcutaneous edema and fluid-like signal was present in 15 patients. Tears of the deltoid muscle or tendon is an unusual finding, but they can be seen in patients with chronic massive rotator cuff tears. Partial thickness tears tend to involve the undersurface of the deltoid muscle and tendon. Associated findings such as intramuscular cyst or ganglion in the deltoid muscle belly and subcutaneous edema or fluid-like signal overlying the deltoid in a patient with a rotator cuff tear should raise the suspicion of a deltoid tear. (orig.)

  12. Deltoid muscle and tendon tears in patients with chronic rotator cuff tears

    Energy Technology Data Exchange (ETDEWEB)

    Ilaslan, Hakan; Recht, Michael P. [Cleveland Clinic, Musculoskeletal Radiology/A21, Division of Radiology, Cleveland, OH (United States); Iannotti, Joseph P. [Cleveland Clinic, Department of Orthopedic Surgery, Cleveland, OH (United States)

    2007-06-15

    To describe the magnetic resonance imaging (MRI) appearances of tears of the deltoid muscle and tendon in patients with rotator cuff tears and without a prior history of shoulder surgery. Deltoid tears diagnosed on MR examinations were prospectively recorded between February 2003 through June 2004. The images of these patients were then retrospectively reviewed to determine the location of the deltoid tear, the presence of rotator cuff tears, tendon retraction, muscle atrophy, degree of humeral head subluxation, bony erosive changes involving the undersurface of the acromion, and the presence of edema or fluid-like signal intensity in the deltoid muscle and overlying subcutaneous tissues. There were 24 (0.3%) patients with deltoid tears; nine men and 15 women. The age range was 54 to 87 (average 73) years. The right side was involved in 20 cases, and the left in four cases. Fifteen patients had full thickness and nine had partial thickness tears of the deltoid. Shoulder pain was the most common presenting symptom. The physical examination revealed a defect in the region of the deltoid in two patients. Nineteen patients had tears in the muscle belly near the musculotendinous junction, and five had avulsion of the tendon from the acromial origin. Full thickness rotator cuff tears were present in all of the patients, and 22 patients had associated muscle atrophy. Subcutaneous edema and fluid-like signal was present in 15 patients. Tears of the deltoid muscle or tendon is an unusual finding, but they can be seen in patients with chronic massive rotator cuff tears. Partial thickness tears tend to involve the undersurface of the deltoid muscle and tendon. Associated findings such as intramuscular cyst or ganglion in the deltoid muscle belly and subcutaneous edema or fluid-like signal overlying the deltoid in a patient with a rotator cuff tear should raise the suspicion of a deltoid tear. (orig.)

  13. Parameter Estimation and Sensitivity Analysis of an Urban Surface Energy Balance Parameterization at a Tropical Suburban Site

    Science.gov (United States)

    Harshan, S.; Roth, M.; Velasco, E.

    2014-12-01

    Forecasting of the urban weather and climate is of great importance as our cities become more populated and considering the combined effects of global warming and local land use changes which make urban inhabitants more vulnerable to e.g. heat waves and flash floods. In meso/global scale models, urban parameterization schemes are used to represent the urban effects. However, these schemes require a large set of input parameters related to urban morphological and thermal properties. Obtaining all these parameters through direct measurements are usually not feasible. A number of studies have reported on parameter estimation and sensitivity analysis to adjust and determine the most influential parameters for land surface schemes in non-urban areas. Similar work for urban areas is scarce, in particular studies on urban parameterization schemes in tropical cities have so far not been reported. In order to address above issues, the town energy balance (TEB) urban parameterization scheme (part of the SURFEX land surface modeling system) was subjected to a sensitivity and optimization/parameter estimation experiment at a suburban site in, tropical Singapore. The sensitivity analysis was carried out as a screening test to identify the most sensitive or influential parameters. Thereafter, an optimization/parameter estimation experiment was performed to calibrate the input parameter. The sensitivity experiment was based on the "improved Sobol's global variance decomposition method" . The analysis showed that parameters related to road, roof and soil moisture have significant influence on the performance of the model. The optimization/parameter estimation experiment was performed using the AMALGM (a multi-algorithm genetically adaptive multi-objective method) evolutionary algorithm. The experiment showed a remarkable improvement compared to the simulations using the default parameter set. The calibrated parameters from this optimization experiment can be used for further model

  14. Retinal tear presenting in a patient with ectrodactyly ectodermal dysplasia.

    Science.gov (United States)

    Grogg, Jane Ann; Port, Nicholas; Graham, Trevor

    2014-04-01

    This article aims to report a case of known ectrodactyly ectodermal dysplasia in a young male patient who subsequently was found to have a retinal tear and localized retinal detachment. This is a case report of a 22-year-old white male patient with a history of ectrodactyly ectodermal dysplasia. Our patient initially presented with an acute exacerbation of bilateral, red, irritated eyes. No recent changes in vision were reported. The patient's ocular surface disease was consistent with ectrodermal dysplasia syndrome. However, a dilated fundus examination revealed an asymptomatic retinal tear with a surrounding localized retinal detachment. In this case, the patient presented with longstanding ocular surface disease known to be associated with this patient's inherited ectoderm disorder. In addition, this patient revealed a retinal tear, raising the possibility that patients with inherited congenital ectodermal dysplasia could be at risk for damaged structures originating from the neural ectoderm. In this heterogeneous disease, we are contributing to the existing literature a case of ectodermal dysplasia syndrome with obvious ectodermal complications that also had retinal findings leading us to speculate question if neural ectoderm could also be involved in this inherited disease.

  15. Tearing instability in a tokamak with a noncircular cross section

    Energy Technology Data Exchange (ETDEWEB)

    Arsenin, V. V., E-mail: arsenin-vv@nrcki.ru; Skovoroda, A. A., E-mail: skovoroda-aa@nrcki.ru [National Research Center Kurchatov Institute (Russian Federation)

    2016-12-15

    Using a straight-column model to describe tokamak plasma with a noncircular cross section, it is shown how to (i) find the boundary of tearing instability from the condition of existence of a magnetohydrodynamic plasma equilibrium different from that of a straight cylinder by solving a two-dimensional linear boundary-value problem with a second-order equation with respect to the flux coordinate and (ii) find the spatial structure of the tearing mode and the corresponding effective Δ' when there is only one resonance magnetic surface in the plasma for a given axial wavenumber by solving some kind of a boundary-value problem for the perturbation. The proposed approach is illustrated by numerical calculations for the case of an elliptical cross section as an example.

  16. Tearing-mode stability of a forming Spheromak plasma

    International Nuclear Information System (INIS)

    Heidbrink, W.W.; Jardin, S.C.; Chance, M.S.

    1981-10-01

    The results of numerical calculations of Δ' for a class of equilibria typical of those encountered during the early formation stage of the S1 Spheromak are presented. The equilibrium plasma is assumed to be cylindrically symmetric and pressureless. It encloses a current carrying perfect conductor (flux core) and is surrounded by a vacuum with zero longitudinal field. Stability boundaries in the space formed by the equilibrium parameters are mapped. The plasma is tearing mode stable provided B/sub z//B/sub theta/ at the flux core is below a certain critical value which depends on the equilibrium parameters. For typical equilibria, this critical value is 0.65

  17. [A study on the diagnostic value of tear film objective scatter index in dry eye].

    Science.gov (United States)

    Su, Y D; Liang, Q F; Wang, N L; Antoine, Labbè

    2017-09-11

    Objective: To study the sensitivity and specificity of tear film objective scatter index to the diagnosis dry eye disease (DED). Methods: A prospective case-controlled study. Fifty-three patients with DED and 32 healthy age- and sex-matched control subjects were included from July to October 2016. All subjects underwent the examinations sequentially as follows: evaluation of ocular surface disease symptoms using the Ocular Surface Disease Index, optical quality detection, lipid layer thickness, tear film breakup time and SchirmerⅠtest. With Optical Quality Analysis SystemⅡ, the values of modulation transfer function cut off, basic objective scatter index (OSI) and total OSI were measured. To eliminate the influence of other refractive media, the tear film OSI (TF-OSI) was calculated, and the difference in TF-OSI between two groups was analyzed with the independent-samples t test. Spearman's correlation analysis was used to detect the correlation of each parameter in the DED group. With the receiver operating characteristic curve and the area under the curve (AUC), the specificity and sensitivity of TF-OSI and other parameters were described to differentiate DED from normal eyes. Results: In the dry eye group, the value of modulation transfer function cut off (32.07±11.95) was significantly lower than the normal group (39.38±9.44, t=- 3.096, P= 0.003) , and the mean value and dispersion of TF-OSI (0.50±0.43, 0.52±0.81) were higher than the normal group (0.21±0.16, 0.12±0.01) ( t= 4.300, P= 0.000, t= 3.546, P= 0.001) . The mean value of TF-OSI had a positive correlation with lipid layer thickness ( r= 0.365, P= 0.007) and dispersion of TF-OSI ( r= 0.581, P= 0.000), and a negative correlation with MTF cut off ( r=- 0.368, P= 0.007). To the diagnostic value of DED, the mean value of TF-OSI had a sensitivity of 0.736, a specificity of 0.762, and the AUC was 0.764. The dispersion of TF-OSI had a sensitivity of 0.811 and a specificity of 0.810, and the AUC was 0

  18. Estimation of subsurface hydrological parameters around Akwuke, Enugu, Nigeria using surface resistivity measurements

    International Nuclear Information System (INIS)

    Utom, Ahamefula U; Odoh, Benard I; Egboka, Boniface C E; Egboka, Nkechi E; Okeke, Harold C

    2013-01-01

    As few boreholes may be available and carrying out pumping tests can be expensive and time consuming, relationships between aquifer characteristics and the electrical parameters of different geoelectric layers exist. Data from 19 vertical electrical soundings (VESs; 13 of these selected for evaluation) was recorded with a Schlumberger electrode configuration in the area around Akwuke, Enugu, Nigeria. The data was interpreted by computer iterative modelling with curve matching for calibration purposes. Geoelectric cross-sections along a number of lines were prepared to ascertain the overall distribution of the resistivity responses of the subsurface lithology. Identified probable shallow aquifer resistivity, thickness and depth values are in the range of 28–527 Ωm, 2.1–22.5 m and 3.1–28.3 m respectively. As our aquifer system consists of fine-grained, clay–silty sand materials, a modification of the Archie equations (Waxman–Smits model) was adopted to determine the true formation factor using the relationship between the apparent formation factor and the pore water resistivity. This representation of the effects of a separate conducting path due to the presence of clay particles in the aquifer materials was used in making reliable estimations of aquifer properties. The average hydraulic conductivity of 8.96 × 10 −4 m s −1 transmissivity ranging between 1.88 × 10 −3 and 2.02 × 10 −3 m 2 s −1 estimated from surface resistivity measurements correlated well with the available field data. Results of the study also showed a direct relationship between aquifer transmissivity and modified transverse resistance (R 2 = 0.85). (paper)

  19. Tearing modes induced by perpendicular electron cyclotron resonance heating in the KSTAR tokamak

    Science.gov (United States)

    Lee, H. H.; Lee, S. G.; Seol, J.; Aydemir, A. Y.; Bae, C.; Yoo, J. W.; Na, Y. S.; Kim, H. S.; Woo, M. H.; Kim, J.; Joung, M.; You, K. I.; Park, B. H.

    2014-10-01

    This paper reports on experimental evidence that shows perpendicular electron cyclotron resonance heating (ECRH) can trigger classical tearing modes when deposited near a rational flux surface. The complex evolution of an m = 2 island is followed during current ramp-up in KSTAR plasmas, from its initial onset as the rational surface enters the ECRH resonance layer to its eventual lock on the wall after the rational surface leaves the layer. Stability analysis coupled to a transport calculation of the current profile with ECRH shows that the perpendicular ECRH may play a significant role in triggering and destabilizing classical m = 2 tearing modes, in agreement with our experimental observation.

  20. Pinus sylvestris L. needle surface wettability parameters as indicators of atmospheric environment pollution impacts: Novel contact angle hysteresis methodology

    Science.gov (United States)

    Pogorzelski, Stanisław J.; Rochowski, Pawel; Szurkowski, Janusz

    2014-02-01

    An investigation of water contact angles (CAs), contact angle hysteresis (CAH) was carried out for 1-year to 4-year old needles (Pinus sylvestris) collected in urban (Gdansk) and rural (Karsin) locations using an original measuring technique based on the geometry of the drop on a vertical filament. Concentrations of air pollutants (SO2, NOx, C6H6, and suspended particular matter - SPM) currently considered to be most important in causing direct damage to vegetation were simultaneously monitored. A set of the surface wettability parameters: the apparent surface free energy γSV, adhesive film tension Π, work of adhesion WA, and spreading WS, were determined from CAH data using the approach developed by Chibowski (2003) to quantify the surface energetics of the needle substrata affected by aging and pollution impacts. This formalism relates the total apparent surface free energy of the solid γSV with only three measurable quantities: the surface tension of the probe liquid γLV and its advancing θA and receding θR contact angle hysteresis. Since CAH depends on the outermost wax layer surface roughness and spatial physicochemical heterogeneity of a solid surface, CA data were corrected using surface architecture profiles registered with confocal scanning laser microscopy. It was found that the roughness parameter r is significantly negatively correlated (R = -0.74) with the needle age (collected at Karsin). The needle surface aging process resulted in its surface hydrophilization (CA↓ and CAH↓ with γSV↑ and WA↑). A temporal evolution of the needles wettability was traced with the data point distribution in the 2D space of CAH plotted versus WS. The wettability parameters were closely correlated to pollutant concentrations as evidenced from Spearman's rank correlation procedure (R = 0.63-0.91; p biological systems.

  1. Adsorption of human tear lipocalin to human meibomian lipid films.

    Science.gov (United States)

    Millar, Thomas J; Mudgil, Poonam; Butovich, Igor A; Palaniappan, Chendur K

    2009-01-01

    Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (Pi-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37 degrees C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in Pi-T profiles and the microscopic appearance of the films. It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film.

  2. Adsorption of Human Tear Lipocalin to Human Meibomian Lipid Films

    Science.gov (United States)

    Millar, Thomas J.; Mudgil, Poonam; Butovich, Igor A.; Palaniappan, Chendur K.

    2009-01-01

    Purpose Tear lipocalin (Tlc) is a major lipid binding protein in tears and is thought to have an important role in stabilizing the Meibomian lipid layer by transferring lipids to it from the aqueous layer or ocular surface, or by adsorbing to it directly. These possible roles have been investigated in vitro using human Tlc. Methods Tlc was purified from human tears by size exclusion chromatography followed by ion exchange chromatography. Three additional samples of the Tlc were prepared by lipidation, delipidation, and relipidation. The lipids extracted from the purified Tlc were analyzed by HPLC-MS followed by fragmentation. Adsorption of these different forms of Tlc to a human Meibomian lipid film spread on the surface of an artificial tear buffer in a Langmuir trough were observed by recording changes in the pressure with time (∏-T profile) and monitoring the appearance of the film microscopically. These results were compared with similar experiments using a bovine Meibomian lipid film. Results The results indicated that Tlc binds slowly to a human Meibomian lipid film compared with lysozyme or lactoferrin, even at 37°C. The adsorption of Tlc to a human Meibomian lipid film was very different from its adsorption to a bovine Meibomian lipid film, indicating the nature of the lipids in the film is critical to the adsorption process. Similarly, the different forms of Tlc had quite distinct adsorption patterns, as indicated both by changes in ∏-T profiles and the microscopic appearance of the films. Conclusions It was concluded that human Tlc was capable of adsorbing to and penetrating into a Meibomian lipid layer, but this process is very complex and depends on both the types of lipids bound to Tlc and the lipid complement comprising the Meibomian lipid film. PMID:18757516

  3. Evaluation of outgassing, tear strength, and detail reproduction in alginate substitute materials.

    Science.gov (United States)

    Baxter, R T; Lawson, N C; Cakir, D; Beck, P; Ramp, L C; Burgess, J O

    2012-01-01

    To compare three alginate substitute materials to an alginate impression material for cast surface porosity (outgassing), tear strength, and detail reproduction. Detail reproduction tests were performed following American National Standards Institute/American Dental Association (ANSI/ADA) Specification No. 19. To measure tear strength, 12 samples of each material were made using a split mold, placed in a water bath until testing, and loaded in tension until failure at a rate of 500 mm/min using a universal testing machine. For cast surface porosity testing, five impressions of a Teflon mold with each material were placed in a water bath (37.8°C) for the in-mouth setting time and poured with vacuum-mixed Silky Rock die stone at 5, 10, 30, and 60 minutes from the start of mixing. The gypsum samples were analyzed with a digital microscope for surface porosity indicative of hydrogen gas release by comparing the surface obtained at each interval with four casts representing no, little, some, and significant porosity. Data analysis was performed using parametric and Kruskal-Wallis analysis of variance (ANOVA), Tukey/Kramer post-hoc tests (α=0.05), and individual Mann-Whitney U tests (α=0.0167). All alginate substitute materials passed the detail reproduction test. Tear strength of the alginate substitute materials was significantly better than alginate and formed three statistically different groups: AlgiNot had the lowest tear strength, Algin-X Ultra had the highest tear strength, and Position Penta Quick had intermediate tear strength. Significant variation in outgassing existed between materials and pouring times (palginate substitute materials exhibited the least outgassing and cast porosity 60 minutes after mixing. Detail reproduction and tear strength of alginate substitute materials were superior to traditional alginate. The outgassing effect was minimal for most materials tested. Alginate substitute materials are superior replacements for irreversible

  4. An international comparison of surface texture parameters quantification on polymer artefacts using optical instruments

    DEFF Research Database (Denmark)

    Tosello, Guido; Haitjema, H.; Leach, R.K.

    2016-01-01

    An international comparison of optical instruments measuring polymer surfaces with arithmetic mean height values in the sub-micrometre range has been carried out. The comparison involved sixteen optical surface texture instruments (focus variation instruments, confocal microscopes and coherent...

  5. Percentage Level of Tannin fur Rabbit for Leather Concerning Stitch Tearing Strength, Tearing Strength and Flexibility

    Directory of Open Access Journals (Sweden)

    Mustakim Mustakim

    2012-02-01

    Full Text Available The purpose of this study was to find out the appropriate of tannin level for rabbit fur leather concerning stitch tearing strength, tearing strength, and flexibility. The result were expected to contribute good information for the society, leather craftsman, and further researchers about fur leather tanning especially rabbit fur leather with tannin concerning stitch tearing strength, tearing strength and flexibility. The material that used were 12 pieces of four months of rabbit skin. The research method was Completely Randomized Design, consist of three treatments of tannin, they were: M1 (mimosa 15%, M2 (mimosa 20%, and M3 (mimosa 25%. Each of treatment hold on four repetition, the variables which measured were stitch tearing strength, tearing strength, and flexibility of fur leather. Data were  analysed by analysis variance followed by Duncan’s Multiple Range Test. The result of this research indicate that the use level of tannin give significant influence (P<0.05 among stitch tearing strength, tearing strength. It gave a very significant influence (P<0.01 for flexibility of rabbit fur leather. Based on the result, can be concluded that 25 % of tannin (mimosa, produce the best  result on stitch tearing strength and tearing strength. The increase of tannin offer will decrease the flexibility of fur leather but the lowest tannin produced the best flexibility of fur leather (15 percent. The best quality of rabbit fur leather produced by 25 % of tannin.   Keywords : leather, tannin, quality

  6. Mass spectrometric identification of phospholipids in human tears and tear lipocalin.

    Science.gov (United States)

    Dean, Austin W; Glasgow, Ben J

    2012-04-02

    The purpose of this article was to identify by mass spectrometry phosphocholine lipids in stimulated human tears and determine the molecules bound to tear lipocalin or other proteins. Tear proteins were separated isocratically from pooled stimulated human tears by gel filtration fast performance liquid chromatography. Separation of tear lipocalin was confirmed by SDS tricine gradient PAGE. Protein fractions were extracted with chloroform/methanol and analyzed with electrospray ionization MS/MS triple quadrupole mass spectrometry in precursor ion scan mode for select leaving groups. For quantification, integrated ion counts were derived from standard curves of authentic compounds of phosphatidylcholine (PC) and phosphatidylserine. Linear approximation was possible from integration of the mass spectrometrically obtained ion peaks at 760 Da for the PC standard. Tears contained 194 ng/mL of the major intact PC (34:2), m/z 758.6. Ten other monoisotopic phosphocholines were found in tears. A peak at 703.3 Da was assigned as a sphingomyelin. Four lysophosphatidylcholines (m/z 490-540) accounted for about 80% of the total integrated ion count. The [M+H](+) compound, m/z 496.3, accounted for 60% of the signal intensity. Only the tear lipocalin-bearing fractions showed phosphocholines (104 ng/mL). Although the intact phospholipids bound to tear lipocalin corresponded precisely in mass and relative signal intensity to that found in tears, we did not identify phosphocholines between m/z 490 and 540 in any of the gel-filtration fractions. Phospholipids, predominantly lysophospholipids, are present in tears. The higher mass intact PCs in tears are native ligands of tear lipocalin.

  7. Improvements to the swath-level near-surface atmospheric state parameter retrievals within the NRL Ocean Surface Flux System (NFLUX)

    Science.gov (United States)

    May, J. C.; Rowley, C. D.; Meyer, H.

    2017-12-01

    The Naval Research Laboratory (NRL) Ocean Surface Flux System (NFLUX) is an end-to-end data processing and assimilation system used to provide near-real-time satellite-based surface heat flux fields over the global ocean. The first component of NFLUX produces near-real-time swath-level estimates of surface state parameters and downwelling radiative fluxes. The focus here will be on the satellite swath-level state parameter retrievals, namely surface air temperature, surface specific humidity, and surface scalar wind speed over the ocean. Swath-level state parameter retrievals are produced from satellite sensor data records (SDRs) from four passive microwave sensors onboard 10 platforms: the Special Sensor Microwave Imager/Sounder (SSMIS) sensor onboard the DMSP F16, F17, and F18 platforms; the Advanced Microwave Sounding Unit-A (AMSU-A) sensor onboard the NOAA-15, NOAA-18, NOAA-19, Metop-A, and Metop-B platforms; the Advanced Technology Microwave Sounder (ATMS) sensor onboard the S-NPP platform; and the Advanced Microwave Scannin Radiometer 2 (AMSR2) sensor onboard the GCOM-W1 platform. The satellite SDRs are translated into state parameter estimates using multiple polynomial regression algorithms. The coefficients to the algorithms are obtained using a bootstrapping technique with all available brightness temperature channels for a given sensor, in addition to a SST field. For each retrieved parameter for each sensor-platform combination, unique algorithms are developed for ascending and descending orbits, as well as clear vs cloudy conditions. Each of the sensors produces surface air temperature and surface specific humidity retrievals. The SSMIS and AMSR2 sensors also produce surface scalar wind speed retrievals. Improvement is seen in the SSMIS retrievals when separate algorithms are used for the even and odd scans, with the odd scans performing better than the even scans. Currently, NFLUX treats all SSMIS scans as even scans. Additional improvement in all of

  8. The Role of Friction Stir Processing (FSP Parameters on TiC Reinforced Surface Al7075-T651 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Felipe García-Vázquez

    Full Text Available Abstract: Aluminum alloys are very promising for structural applications in aerospace, military and transportation industries due to their light weight, high strength-to-weight ratio and excellent resistance to corrosion. In comparison to unreinforced aluminum alloys, aluminum/aluminum alloy matrix composites reinforced with ceramic phases exhibit higher strength and hardness, improved tribological characteristics. A novel surface modifying technique, friction stir processing (FSP, has been developed for fabrication of surface composite with an improved performance. The effect of FSP parameters such as number of passes, direction of each pass, sealed or unsealed groove on microstructure was investigated. In this work, nano-particles of TiC (2% in weight were added to aluminum alloy AA7075-T651 to produce a functional surface. Fixed parameters for this AA7075 alloy were used; rotation speed of 1000 rpm, travel speed of 300 mm/min and pin penetration of 2.8 mm. Optical microscopy (OM, scanning electron microscopy (SEM and atomic force microscopy (AFM were employed to study the microstructure of the fabricated surface composites. The results indicated that the selected FSP parameters influenced the area of surface composite, distribution of TiC particles and micro-hardness of the surface composites. Finally, in order to evaluate rate wear the pin on disk test was carried out.

  9. Image-based Exploration of Iso-surfaces for Large Multi- Variable Datasets using Parameter Space.

    KAUST Repository

    Binyahib, Roba S.

    2013-01-01

    -surfaces superimposed on each other. The result is the same as calculating multiple iso- surfaces from the original data but without the memory and processing overhead. Our tool also allows the user to change the (scalar) values superimposed on each of the surfaces

  10. Optimisation on processing parameters for minimising warpage on side arm using response surface methodology (RSM) and particle swarm optimisation (PSO)

    Science.gov (United States)

    Rayhana, N.; Fathullah, M.; Shayfull, Z.; Nasir, S. M.; Hazwan, M. H. M.; Sazli, M.; Yahya, Z. R.

    2017-09-01

    This study presents the application of optimisation method to reduce the warpage of side arm part. Autodesk Moldflow Insight software was integrated into this study to analyse the warpage. The design of Experiment (DOE) for Response Surface Methodology (RSM) was constructed and by using the equation from RSM, Particle Swarm Optimisation (PSO) was applied. The optimisation method will result in optimised processing parameters with minimum warpage. Mould temperature, melt temperature, packing pressure, packing time and cooling time was selected as the variable parameters. Parameters selection was based on most significant factor affecting warpage stated by previous researchers. The results show that warpage was improved by 28.16% for RSM and 28.17% for PSO. The warpage improvement in PSO from RSM is only by 0.01 %. Thus, the optimisation using RSM is already efficient to give the best combination parameters and optimum warpage value for side arm part. The most significant parameters affecting warpage are packing pressure.

  11. Sensitivities of surface wave velocities to the medium parameters in a radially anisotropic spherical Earth and inversion strategies

    Directory of Open Access Journals (Sweden)

    Sankar N. Bhattacharya

    2015-11-01

    Full Text Available Sensitivity kernels or partial derivatives of phase velocity (c and group velocity (U with respect to medium parameters are useful to interpret a given set of observed surface wave velocity data. In addition to phase velocities, group velocities are also being observed to find the radial anisotropy of the crust and mantle. However, sensitivities of group velocity for a radially anisotropic Earth have rarely been studied. Here we show sensitivities of group velocity along with those of phase velocity to the medium parameters VSV, VSH , VPV, VPH , h and density in a radially anisotropic spherical Earth. The peak sensitivities for U are generally twice of those for c; thus U is more efficient than c to explore anisotropic nature of the medium. Love waves mainly depends on VSH while Rayleigh waves is nearly independent of VSH . The sensitivities show that there are trade-offs among these parameters during inversion and there is a need to reduce the number of parameters to be evaluated independently. It is suggested to use a nonlinear inversion jointly for Rayleigh and Love waves; in such a nonlinear inversion best solutions are obtained among the model parameters within prescribed limits for each parameter. We first choose VSH, VSV and VPH within their corresponding limits; VPV and h can be evaluated from empirical relations among the parameters. The density has small effect on surface wave velocities and it can be considered from other studies or from empirical relation of density to average P-wave velocity.

  12. Post-lens tear turbidity and visual quality after scleral lens wear.

    Science.gov (United States)

    Carracedo, Gonzalo; Serramito-Blanco, Maria; Martin-Gil, Alba; Wang, Zicheng; Rodriguez-Pomar, Candela; Pintor, Jesús

    2017-11-01

    The aim was to evaluate the turbidity and thickness of the post-lens tear layer and its effect on visual quality in patients with keratoconus after the beginning of lens wear and before lens removal at the end of eight hours. Twenty-six patients with keratoconus (aged 36.95 ± 8.95 years) participated voluntarily in the study. The sample was divided into two groups: patients with intrastromal corneal ring (ICRS group) and patients without ICRS (KC group). Distance visual acuity (VA), contrast sensitivity, pachymetry, post-lens tear layer height and post-lens tear layer turbidity (percentage area occupied and number of particles per mm 2 ) were evaluated with optical coherence tomography before and after wearing a scleral lens. A significant increase of turbidity was found in all groups assessed (p turbidity parameters with distance VA but no correlation between turbidity and post-lens tear layer thickness at the beginning was found (p > 0.05). A strong correlation in all groups between the post-lens tear layer at the beginning and differences of tear layer thickness between two measures was also found (p turbidity. © 2017 Optometry Australia.

  13. Kinetic theory of tearing instability

    International Nuclear Information System (INIS)

    Hazeltine, R.D.; Dobrott, D.; Wang, T.S.

    1975-01-01

    The guiding-center kinetic equation with Fokker-Planck collision term is used to study, in cylindrical geometry, a class of dissipative instabilities of which the classical tearing mode is an archetype. Variational solution of the kinetic equation obviates the use of an approximate Ohm's law or adiabatic assumption, as used in previous studies, and it provides a dispersive relation which is uniformly valid for any ratio of wave frequency to collision frequency. One result of using the rigorous collision operator is the prediction of a new instability. This instability, driven by the electron temperature gradient, is predicted to occur under the long mean-free path conditions of present tokamak experiments, and has significant features in common with the kink-like oscillations observed in such experiments

  14. Shear flows induced by nonlinear evolution of double tearing modes

    International Nuclear Information System (INIS)

    Wang Zhengxiong; Kishimoto, Y.; Li, J. Q.; Wang Xiaogang; Dong, J. Q.

    2008-01-01

    Shear flows induced by nonlinear evolution of double tearing modes are investigated in a resistive magnetohydrodynamic model with slab geometry. It is found that intensive and thin poloidal shear flow layers are generated in the magnetic island region driven by coupled reconnection process at both rational surfaces. The structure of the flow layers keeps evolving after the merging of magnetic separatrices and forms a few narrow vortices along the open field lines in the final stage of magnetic reconnection. The effects of the distance between both rational surfaces and the initial magnetic shear on the nonlinear evolution of the plasma flows are also taken into consideration and the relevant mechanism is discussed

  15. Collisionless tearing mode reconnection at the dayside magnetopause of the earth's magnetosphere

    International Nuclear Information System (INIS)

    Quest, K.B.

    1982-01-01

    The purpose of this thesis was to determine if the collisionless tearing mode, a plasma instability, is a viable mechanism for interconnecting field lines at the dayside magnetopause. More generally, it was wished to test theoretically the assertion that collisionless tearing is a probable first step in cosmical reconnection. The procedure was to model the magnetopause as a local one-dimensional Vlasov equilibrium, and then calculate the linear and nonlinear stability properties of tearing and tearing-like oscillations. Quantitative estimates of the range of plasma parameter space over which significant growth occurs were obtained. Assuming that significant tearing mode growth implies significant reconnection, conditions were determined for which tearing will be important to dayside reconnection. Linearly it was found that the growth rate is relatively insensitive to the temperature of the species, but depends sensitively on (1) the thickness of the magnetopause current, (2) the number density at the location of the singular layer, and (3) the magnitude of the magnetic shear. For significant linear growth the magnetopause half-sheet thickness was required to be on the order of or less than a thermal ion gyroradius, the number density was required to be no more than 100 cm - 3 , and the magnetosheath field was required to be locally antialigned with the magnetospheric field. If the above conditions are met, which are stringent but not impossible, the mode will linearly amplify. Another topic examined is the question of the structure of the tearing eigenmodes at the dayside magnetopause. By considering finite transit time effects on electron Landau resonance it was concluded that magnetopause tearing turbulence probably occurs in spatially bounded wave packets

  16. Effect of machining parameters on surface textures in EDM of Fe-Mn-Al alloy

    International Nuclear Information System (INIS)

    Guu, Y.H.; Hou, Max Ti-Kuang

    2007-01-01

    In this work, the surface characteristics caused by EDM were analyzed by means of the atomic force microscopy (AFM) technique. An empirical model of Fe-Mn-Al alloy was proposed based on the experimental data. A qualitative energy dispersive spectroscopic analyzer was used to measure the chemical composition of the specimen. Surface hardness was determined with a microhardness tester. Experimental results indicate that the EDM process causes a ridged surface and induces machining damage in the surface layer, and increases the surface roughness. The depth of micro-cracks, micro-voids and machined damage increase with an increase in the amount of pulsed current and pulse-on duration. The effect of the magnitude of the pulse-on duration on the surface texture of the specimen is more significant than the pulsed current. Furthermore, the AFM method reveals the 3D surface textures of the EDM specimen with a nanometer scale

  17. Tear ferning in normal dogs and dogs with keratoconjunctivitis sicca ...

    African Journals Online (AJOL)

    This study evaluates tear ferning as an ancillary technique for the evaluation of the canine tear film in normal eyes and eyes affected by keratoconjunctivitis sicca (KCS). Thirty dogs with KCS and 50 control dogs with normal tear film were evaluated with a full ophthalmoscopic examination and a Schirmer tear test type 1 ...

  18. The resistive tearing instability for generalized resistivity models: Applications

    International Nuclear Information System (INIS)

    Birk, G.T.; Otto, A.

    1991-01-01

    The dispersion relation for the resistive tearing mode is investigated with a general form of the resistivity that allows for evaluating the dependence of the mode on the anomalous dissipation caused by the lower-hybrid-drift turbulence and the ion-acoustic turbulence. The coupling of the plasma dynamic and radiative processes due to a temperature-dependent Spitzer resistivity are also discussed. The dispersion relation is solved numerically for two-dimensional equilibrium configurations with applications to the Earth's magnetosphere and the solar corona. In the case of the parameter regimes of the magnetopause and the solar corona, growth rates that result in realistic time scales for the respective dynamic processes as flux transfer events and solar flares were found. Moreover, the influence of a nonvanishing component of the magnetic field normal to the current sheet on the dispersion relation is examined. The normal field component leads to overstable modes and the growth rate of the pure tearing mode is not altered, whereas the radiative tearing mode is damped effectively

  19. Acetabular labral tears: contrast-enhanced MR imaging under continuous leg traction

    Energy Technology Data Exchange (ETDEWEB)

    Nishii, T. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Nakanishi, K. [Dept. of Radiology, Osaka Univ. Medical School, Suita (Japan); Sugano, N. [Dept. of Orthopaedic Surgery, Osaka Univ. Medical School, Suita (Japan); Naito, H. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Tamura, S. [Div. of Functional Diagnostic Imaging, Biomedical Research Center, Osaka Univ. Medical School, Suita (Japan); Ochi, T. [Dept. of Orthopaedic Surgery, Osaka Univ. Medical School, Suita (Japan)

    1996-05-01

    The objective of this study was to evaluate the effects of continuous leg traction on contrast-enhanced MR imaging of the hip joint and to determine whether MR imaging under these conditions is useful for demonstrating acetabular labral tears. Nineteen hips underwent MR imaging with a T1-weighted spin-echo sequence, followed by MR imaging under continuous leg traction after intravenous injection of gadolinium-DTPA. Joint fluid enhancement and labral contour detection were evaluated. Eleven hips had labral tears shown by conventional arthrography, arthroscopy and macroscopic surgical findings. Assessment of labral tears by MR imaging was correlated with the diagnosis based on these standard techniques. Joint fluid enhancement was obtained in all hips at 30 min after injection. Superior and inferior labral surfaces were completely delineated in 1 hip on the unenhanced MR images, and in 7 and 13 hips, respectively, on the enhanced images under traction. The enhanced images under traction depicted 9 of the 11 labral tears. Comparison between the unenhanced image and the enhanced image under traction avoided mistaking undercutting of the labrum for a tear in 4 hips. Contrast-enhanced MR imaging under traction was valuable for detecting labral tears non-invasively and without radiation. Follow-up examinations using this method in patients with acetabular dysplasia can help to clarify the natural course of labral disorders and enable better treatment planning. (orig./MG)

  20. Glycomic characterization of basal tears and changes with diabetes and diabetic retinopathy.

    Science.gov (United States)

    Nguyen-Khuong, Terry; Everest-Dass, Arun V; Kautto, Liisa; Zhao, Zhenjun; Willcox, Mark D P; Packer, Nicolle H

    2015-03-01

    As a secreted fluid, the state of tear glycosylation is particularly important in the role of immunity of the ocular surface. Tears are a valuable source of non-invasive biomarkers for disease and there are continued efforts to characterize their components thoroughly. In this study, a small volume of basal tears (5 μL) was collected from healthy controls, patients with diabetes without retinopathy and patients with diabetes and retinopathy. The detailed N- and O-linked tear protein glycome was characterized and the relative abundance of each structure determined. Of the 50 N-linked glycans found, 89% were complex with 50% containing a bisecting N-acetylglucosamine, 65% containing a core fucose whilst 33% were sialylated. Of the 8 O-linked glycans detected, 3 were of cores 1 and 5 of core 2 type, with a majority of them being sialylated (90%). Additionally, these glycan structures were profiled across the three diabetic disease groups. Whilst the higher abundant structures did not alter across the three groups, only five low abundance N-linked glycans and 1 O-linked glycan did alter with the onset of diabetes mellitus and diabetic retinopathy (DR). These results suggest the conservation of glycan types on basal tear proteins between individuals and point to only small changes in glycan expression on the proteins in tears with the development of diabetes and DR. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  1. US detection of rotator cuff tear

    International Nuclear Information System (INIS)

    Soble, M.G.; Guay, R.C.; Kaye, A.D.

    1988-01-01

    Between June 1986 and April 1988, 75 patients suspected of having a tear of the rotator cuff underwent shoulder sonography and arthrography. Compared with anthrography, US demonstrated 92% of rotor cuff tears, with a specificity of 84% and a negative predictive value of 95%. In 30 patients who underwent surgery for a rotator cuff tear or other soft-tissue abnormality, sonography demonstrated a sensitivity of 93% and specificity of 73%, while arthrography demonstrated a sensitivity of 87% and specificity of 100%. The above data indicate that US is a useful, noninvasive screening procedure for patients suspected of having rotator cuff injury

  2. Application of silver films with different roughness parameter for septic human serum albumin detection by Surface Enhanced Raman Spectroscopy

    Science.gov (United States)

    Zyubin, A. Y.; Konstantinova, E. I.; Matveeva, K. I.; Slezhkin, V. A.; Samusev, I. G.; Demin, M. V.; Bryukhanov, V. V.

    2018-01-01

    In this paper, the rough silver films parameters investigation, used as media for surface enhancement Raman spectroscopy for health and septic human serum albumin (HSA) study results have been presented. The detection of small concentrations of HSA isolated from blood serum and it main vibrational groups identification has been done.

  3. Computed tear film and osmolarity dynamics on an eye-shaped domain

    Science.gov (United States)

    Li, Longfei; Braun, Richard J.; Driscoll, Tobin A.; Henshaw, William D.; Banks, Jeffrey W.; King-Smith, P. Ewen

    2016-01-01

    The concentration of ions, or osmolarity, in the tear film is a key variable in understanding dry eye symptoms and disease. In this manuscript, we derive a mathematical model that couples osmolarity (treated as a single solute) and fluid dynamics within the tear film on a 2D eye-shaped domain. The model includes the physical effects of evaporation, surface tension, viscosity, ocular surface wettability, osmolarity, osmosis and tear fluid supply and drainage. The governing system of coupled non-linear partial differential equations is solved using the Overture computational framework, together with a hybrid time-stepping scheme, using a variable step backward differentiation formula and a Runge–Kutta–Chebyshev method that were added to the framework. The results of our numerical simulations provide new insight into the osmolarity distribution over the ocular surface during the interblink. PMID:25883248

  4. ProTec Tear-Offs: A Preliminary Assessment

    International Nuclear Information System (INIS)

    Peeler, D

    2005-01-01

    The Savannah River National Laboratory (SRNL) has conducted a series of ''scoping'' tests (referred to as Phase 1) to assess the potential use of a Mylar(reg s ign) tear-off system as a primary or secondary protective barrier to minimize acid etching (''frosting''), accidental scratching, and/or radiation damage for shielded cells windows. Conceptually, thin, multi-layered sheets of Mylar (referred to as a ''tear-off'' system) could be directly applied to the Lexan(reg s ign) sheet or glovebox/hood sash window to serve as a secondary (or primary) barrier. Upon degradation of visual clarity due to accidental scratching, spills/splatters, and/or radiation damage, the outer layer (or sheet) of Mylar could be removed ''refreshing'' or restoring the view. Due to the multi-layer aspect, the remaining Mylar layers would provide continued protection for the window from potential reoccurrences (which could be immediate or after some extended time period). Although the concept of using a tear-off system as a protective barrier was conceptually enticing, potential technical issues were identified and addressed as part of this Phase 1 feasibility study. These included resistance to: (1) acid(s) (concentrated (28.9 M) HF, concentrated (15.9M) HNO 3 , 6M HCl, and 0.6M H 3 BO 3 ), (2) base (a simulated sludge with pH of 12.9), (3) gamma radiation (cumulative dose of ∼200,000 rad), and (4) scratch resistance (simulating accidental scratching with the manipulators). Not only can these four factors play a significant role in determining the visual clarity of the integrated system, they can also contribute to the mechanical integrity issues which could dictate the ability to remove the outer layer when visual clarity has degraded. The results of the Phase 1 study clearly indicate that the Mylar tear-off concept (as a primary or secondary protective barrier) is a potential technical solution to prevent or retard excessive damage that would result from acid etching, base damage (as a

  5. Effect of operational conditions of electroerosion machining on the surface microgeometry parameters of steels and alloys

    International Nuclear Information System (INIS)

    Foteev, N.K.

    1976-01-01

    Studies the influence of pulse duration and a series of operating conditions of a ShGI-40-440 spark-machining generator on changes in the basic surface microgeometry characteristics of components of stainless steel 1Kh18N10T, steel St 45 and hard alloy T14K8. The microgeometry characteristics of spark-machined surfaces differ significantly from the corresponding characteristics of surfaces machined by cutting and vibro-rolling

  6. Nonlinear tearing modes in the reversed field pinch

    International Nuclear Information System (INIS)

    Miller, G.

    1989-01-01

    Finite-amplitude islands, which are the saturated states of tearing modes in the reversed field pinch, are calculated. These states are bifurcated noncylindrical equilibrium states. With σ(r) (σequivalentj x B/B 2 ) nonuniform across the plasma, as is consistent with experiment, a variety of m = 1 and m = 0 bifurcated equilibria are possible, instead of just the m = 1 helix calculated for uniform σ(r) by Taylor [in Pulsed High Beta Plasmas, edited by D. Evans (Pergamon, Oxford, 1976), p. 59]. Assuming the magnetic field lines in the reversed field pinch are weakly stochastic, the growth time of an unstable tearing mode is on the inertial time scale, as in the Taylor model, in constrast to growth on the resistive time scale predicted from nonlinear tearing mode theory when magnetic surfaces exist. The dependence of the saturated island width on radius of a conducting shell is investigated. Islands in the reversed field pinch often have magnetic wells in the island interior, which may result in improved confinement in the island regions

  7. Parameters Studies on Surface Initiated Rolling Contact Fatigue of Turnout Rails by Three-Level Unreplicated Saturated Factorial Design

    Directory of Open Access Journals (Sweden)

    Xiaochuan Ma

    2018-03-01

    Full Text Available Surface initiated rolling contact fatigue (RCF, mainly characterized by cracks and material stripping, is a common type of damage to turnout rails, which can not only shorten service life of turnout but also lead to poor running safety of vehicle. The rail surface initiated RCF of turnouts is caused by a long-term accumulation, the size and distribution of which are related to the dynamic parameters of the complicated vehicle-turnout system. In order to simulate the accumulation of rail damage, some random samples of dynamic parameters significantly influencing it should be input. Based on the three-level unreplicated saturated factorial design, according to the evaluation methods of H, P and B statistic values, six dynamic parameters that influence the rail surface initiated RCF in turnouts, namely running speed of vehicle, axle load, wheel-rail profiles, integral vertical track stiffness and wheel-rail friction coefficient, are obtained by selecting 13 dynamic parameters significantly influencing the dynamic vehicle-turnout interaction as the analysis factors, considering four dynamic response results, i.e., the normal wheel-rail contact force, longitudinal creep force, lateral creep force and wheel-rail contact patch area as the observed parameters. In addition, the rail surface initiated RCF behavior in turnouts under different wheel-rail creep conditions is analyzed, considering the relative motion of stock/switch rails. The results show that the rail surface initiated RCF is mainly caused by the tangential stress being high under small creep conditions, the normal and tangential stresses being high under large creep conditions, and the normal stress being high under pure spin creep conditions.

  8. Evaluation of Parameters Affecting Magnetic Abrasive Finishing on Concave Freeform Surface of Al Alloy via RSM Method

    Directory of Open Access Journals (Sweden)

    Mehrdad Vahdati

    2016-01-01

    Full Text Available The attempts of researchers in industries to obtain accurate and high quality surfaces led to the invention of new methods of finishing. Magnetic abrasive finishing (MAF is a relatively new type of finishing in which the magnetic field is used to control the abrasive tools. Applications such as the surface of molds are ones of the parts which require very high surface smoothness. Usually this type of parts has freeform surface. In this study, the effect of magnetic abrasive process parameters on freeform surfaces of parts made of aluminum is examined. This method is obtained through combination of magnetic abrasive process and Control Numerical Computer (CNC. The use of simple hemisphere for installation on the flat area of the magnets as well as magnets’ spark in curve form is a measure done during testing the experiments. The design of experiments is based on response surface methodology. The gap, the rotational speed of the spindle, and the feed rate are found influential and regression equations governing the process are also determined. The impact of intensity of the magnetic field is obtained using the finite element software of Maxwell. Results show that in concave areas of the surface, generally speaking, the surface roughness decreases to 0.2 μm from its initial 1.3 μm roughness. However, in some points the lowest surface roughness of 0.08 μm was measured.

  9. Diadenosine polyphosphates in the tears of aniridia patients.

    Science.gov (United States)

    Peral, Assumpta; Carracedo, Gonzalo; Pintor, Jesús

    2015-08-01

    To quantify diadenosine polyphosphate levels in tears of congenital aniridia patients to estimate the ocular surface changes associated with congenital aniridia compared to normal individuals. Fifteen patients diagnosed with congenital aniridia and a control group of forty volunteers were studied. Tears were collected to quantify the levels of diadenosine polyphosphates Ap4 A and Ap5 A by high-performance liquid chromatography (H.P.L.C). Break-up time (BUT), corneal staining, McMonnies questionnaire and the Schirmer I test were applied to both groups. Dinucleotides in congenital aniridia patients were higher than in control subjects. For the congenital aniridia group, under 15 years old, the values were 0.77 ± 0.01 μm and 0.17 ± 0.02 μm for Ap4 A and Ap5 A, respectively. The group aged from 15 to 40 years old provided concentrations of 4.37 ± 0.97 μm and 0.46 ± 0.05 μm for Ap4 A and Ap5 A, the group over 40 gave concentrations of 11.17 ± 5.53 μm and 0.68 ± 0.17 μm for Ap4 A and Ap5 A. Dinucleotide concentrations increased with age, being statistically significant different among the three age groups (p tear secretion and no dry eye McMonnies scores, except for the group over 40 years old. BUT values decreased and corneal staining increased with age and correlated with the levels of diadenosine polyphosphates (p tears increase in aniridia patients compared with healthy subjects, and they seem to be related with the progression of corneal disorders in aniridia patients, both of which increase with ageing. © 2014 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  10. Classification of ulnar triangular fibrocartilage complex tears. A treatment algorithm for Palmer type IB tears.

    Science.gov (United States)

    Atzei, A; Luchetti, R; Garagnani, L

    2017-05-01

    The classical definition of 'Palmer Type IB' triangular fibrocartilage complex tear, includes a spectrum of clinical conditions. This review highlights the clinical and arthroscopic criteria that enable us to categorize five classes on a treatment-oriented classification system of triangular fibrocartilage complex peripheral tears. Class 1 lesions represent isolated tears of the distal triangular fibrocartilage complex without distal radio-ulnar joint instability and are amenable to arthroscopic suture. Class 2 tears include rupture of both the distal triangular fibrocartilage complex and proximal attachments of the triangular fibrocartilage complex to the fovea. Class 3 tears constitute isolated ruptures of the proximal attachment of the triangular fibrocartilage complex to the fovea; they are not visible at radio-carpal arthroscopy. Both Class 2 and Class 3 tears are diagnosed with a positive hook test and are typically associated with distal radio-ulnar joint instability. If required, treatment is through reattachment of the distal radio-ulnar ligament insertions to the fovea. Class 4 lesions are irreparable tears due to the size of the defect or to poor tissue quality and, if required, treatment is through distal radio-ulnar ligament reconstruction with tendon graft. Class 5 tears are associated with distal radio-ulnar joint arthritis and can only be treated with salvage procedures. This subdivision of type IB triangular fibrocartilage complex tear provides more insights in the pathomechanics and treatment strategies. II.

  11. Determination of optimum "multi-channel surface wave method" field parameters.

    Science.gov (United States)

    2012-12-01

    Multi-channel surface wave methods (especially the multi-channel analyses of surface wave method; MASW) are routinely used to : determine the shear-wave velocity of the subsurface to depths of 100 feet for site classification purposes. Users are awar...

  12. Electrostatic effect for the collisionless tearing mode

    International Nuclear Information System (INIS)

    Hoshino, M.

    1987-01-01

    Electron dynamics has not been self-consistently considered in collisionless tearing mode theories to date because of the mathematical complexity of the Vlasov-Maxwell equations. We have found using computer simulations that electrostatic fields play an important role in the tearing mode. Vlasov theory, including the electrostatic field, is investigated for topologies with both antiparallel and nonantiparallel magnetic field lines. The electrostatic field influences the resonant current in the neutral sheet which is a non-MHD effect, and modifies the linear growth rate. At the magnetopause, where the field lines are not antiparallel, the electrostatic effect acts to raise the linear growth rate of the tearing mode. On the other hand, in the magnetotail, where magnetic field lines are antiparallel, the electrostatic effect reduces the tearing mode growth rate. copyright American Geophysical Union 1987

  13. Partial Thickness Rotator Cuff Tears: Current Concepts

    Science.gov (United States)

    Matthewson, Graeme; Beach, Cara J.; Nelson, Atiba A.; Woodmass, Jarret M.; Ono, Yohei; Boorman, Richard S.; Lo, Ian K. Y.; Thornton, Gail M.

    2015-01-01

    Partial thickness rotator cuff tears are a common cause of pain in the adult shoulder. Despite their high prevalence, the diagnosis and treatment of partial thickness rotator cuff tears remains controversial. While recent studies have helped to elucidate the anatomy and natural history of disease progression, the optimal treatment, both nonoperative and operative, is unclear. Although the advent of arthroscopy has improved the accuracy of the diagnosis of partial thickness rotator cuff tears, the number of surgical techniques used to repair these tears has also increased. While multiple repair techniques have been described, there is currently no significant clinical evidence supporting more complex surgical techniques over standard rotator cuff repair. Further research is required to determine the clinical indications for surgical and nonsurgical management, when formal rotator cuff repair is specifically indicated and when biologic adjunctive therapy may be utilized. PMID:26171251

  14. Role of ultrasound in rotator cuff tears

    International Nuclear Information System (INIS)

    Siddiqi, H.A.; Mirza, T.

    2010-01-01

    The study was designed to evaluate the efficacy of ultrasound in rotator cuff tears and to compare it with MRI. Total number of patients was thirty. All of these were above thirty years of age and were referred by clinicians, with shoulder pain for diagnostic workup. Post operative patients were excluded. Ultrasound and Magnetic Resonance Imaging (MRI) were performed on each patient. Same operator performed ultrasound in all patients. Ultrasound (US) and Magnetic Resonance Imaging (MRI) detected equal number of full thickness tears while two partial thickness tears were missed on US. Hypoechoic defect was the most important primary sign while cortical irregularity and fluid in subacromial and subdeltroid busra were the most important secondary signs on US. US was equally effective to MRI in detection of rotator cuff tears. It should be the primary investigation because of its availability, cost effective and real time evaluation provided significant expertise is developed, as it is highly operator dependent. (author)

  15. Influence of toroidal rotation on tearing modes

    Science.gov (United States)

    Cai, Huishan; Cao, Jintao; Li, Ding

    2017-10-01

    Tearing modes stability analysis including toroidal rotation is studied. It is found that rotation affects the stability of tearing modes mainly through the interaction with resistive inner region of tearing mode. The coupling of magnetic curvature with centrifugal force and Coriolis force provides a perturbed perpendicular current, and a return parallel current is induced to affect the stability of tearing modes. Toroidal rotation plays a stable role, which depends on the magnitude of Mach number and adiabatic index Γ, and is independent on the direction of toroidal rotation. For Γ >1, the scaling of growth rate is changed for typical Mach number in present tokamaks. For Γ = 1 , the scaling keeps unchanged, and the effect of toroidal rotation is much less significant, compared with that for Γ >1. National Magnetic Confinement Fusion Science Program and National Science Foundation of China under Grants No. 2014GB106004, No. 2013GB111000, No. 11375189, No. 11075161 and No. 11275260, and Youth Innovation Promotion Association CAS.

  16. An Athlete's Nightmare: Tearing the ACL

    Science.gov (United States)

    ... on the balls of their feet. "If the calf muscles are not absorbing the force, and if the knee is not in the proper position, the knee buckles and tears the ACL," explains Dr. Boden. After her initial ...

  17. Partial Thickness Rotator Cuff Tears: Current Concepts

    Directory of Open Access Journals (Sweden)

    Graeme Matthewson

    2015-01-01

    Full Text Available Partial thickness rotator cuff tears are a common cause of pain in the adult shoulder. Despite their high prevalence, the diagnosis and treatment of partial thickness rotator cuff tears remains controversial. While recent studies have helped to elucidate the anatomy and natural history of disease progression, the optimal treatment, both nonoperative and operative, is unclear. Although the advent of arthroscopy has improved the accuracy of the diagnosis of partial thickness rotator cuff tears, the number of surgical techniques used to repair these tears has also increased. While multiple repair techniques have been described, there is currently no significant clinical evidence supporting more complex surgical techniques over standard rotator cuff repair. Further research is required to determine the clinical indications for surgical and nonsurgical management, when formal rotator cuff repair is specifically indicated and when biologic adjunctive therapy may be utilized.

  18. Effects of diquafosol sodium eye drops on tear film stability in short BUT type of dry eye.

    Science.gov (United States)

    Shimazaki-Den, Seika; Iseda, Hiroyuki; Dogru, Murat; Shimazaki, Jun

    2013-08-01

    To investigate the effects of diquafosol sodium (DQS) eye drops, a purinergic P2Y2 receptor agonist, on tear film stability in patients with unstable tear film (UTF). Two prospective studies were conducted. One was an exploratory nonrandomized trial on 39 eyes with dry eye symptoms and short tear film break-up time (BUT), but without epithelial damage. Changes in symptoms, BUT, Schirmer value, and ocular surface fluorescein staining (FS) scores were studied for 3 months. The other was a randomized clinical trial of DQS and artificial tears (AT) in 17 eyes with short BUT. Eyes with decreased Schirmer values (≤ 5 mm) were excluded. Changes in symptoms, BUT, FS scores, and tear film stability using continuous corneal topographic analysis were studied for 4 weeks. In the exploratory study, while Schirmer values were not significantly increased, significant improvements in symptoms and BUT were noted at both 1 and 3 months. In the randomized clinical trial, significant improvements in symptoms were noted in the DQS group, but not in the AT group, at 2 weeks. BUT was significantly prolonged in the DQS group at 4 weeks but not in the AT group. No significant changes were noted in FS scores or tear film stability. DQS improved subjective symptoms and prolonged BUT in eyes with UTF not associated with low tear secretion and ocular surface epithelial damage. Because many patients who have UTF are refractory to conventional treatments, DQS may offer benefits in the treatment of dry eyes.

  19. Parameter sensitivity analysis of a 1-D cold region lake model for land-surface schemes

    Science.gov (United States)

    Guerrero, José-Luis; Pernica, Patricia; Wheater, Howard; Mackay, Murray; Spence, Chris

    2017-12-01

    Lakes might be sentinels of climate change, but the uncertainty in their main feedback to the atmosphere - heat-exchange fluxes - is often not considered within climate models. Additionally, these fluxes are seldom measured, hindering critical evaluation of model output. Analysis of the Canadian Small Lake Model (CSLM), a one-dimensional integral lake model, was performed to assess its ability to reproduce diurnal and seasonal variations in heat fluxes and the sensitivity of simulated fluxes to changes in model parameters, i.e., turbulent transport parameters and the light extinction coefficient (Kd). A C++ open-source software package, Problem Solving environment for Uncertainty Analysis and Design Exploration (PSUADE), was used to perform sensitivity analysis (SA) and identify the parameters that dominate model behavior. The generalized likelihood uncertainty estimation (GLUE) was applied to quantify the fluxes' uncertainty, comparing daily-averaged eddy-covariance observations to the output of CSLM. Seven qualitative and two quantitative SA methods were tested, and the posterior likelihoods of the modeled parameters, obtained from the GLUE analysis, were used to determine the dominant parameters and the uncertainty in the modeled fluxes. Despite the ubiquity of the equifinality issue - different parameter-value combinations yielding equivalent results - the answer to the question was unequivocal: Kd, a measure of how much light penetrates the lake, dominates sensible and latent heat fluxes, and the uncertainty in their estimates is strongly related to the accuracy with which Kd is determined. This is important since accurate and continuous measurements of Kd could reduce modeling uncertainty.

  20. Uncertainty Quantification and Regional Sensitivity Analysis of Snow-related Parameters in the Canadian LAnd Surface Scheme (CLASS)

    Science.gov (United States)

    Badawy, B.; Fletcher, C. G.

    2017-12-01

    The parameterization of snow processes in land surface models is an important source of uncertainty in climate simulations. Quantifying the importance of snow-related parameters, and their uncertainties, may therefore lead to better understanding and quantification of uncertainty within integrated earth system models. However, quantifying the uncertainty arising from parameterized snow processes is challenging due to the high-dimensional parameter space, poor observational constraints, and parameter interaction. In this study, we investigate the sensitivity of the land simulation to uncertainty in snow microphysical parameters in the Canadian LAnd Surface Scheme (CLASS) using an uncertainty quantification (UQ) approach. A set of training cases (n=400) from CLASS is used to sample each parameter across its full range of empirical uncertainty, as determined from available observations and expert elicitation. A statistical learning model using support vector regression (SVR) is then constructed from the training data (CLASS output variables) to efficiently emulate the dynamical CLASS simulations over a much larger (n=220) set of cases. This approach is used to constrain the plausible range for each parameter using a skill score, and to identify the parameters with largest influence on the land simulation in CLASS at global and regional scales, using a random forest (RF) permutation importance algorithm. Preliminary sensitivity tests indicate that snow albedo refreshment threshold and the limiting snow depth, below which bare patches begin to appear, have the highest impact on snow output variables. The results also show a considerable reduction of the plausible ranges of the parameters values and hence reducing their uncertainty ranges, which can lead to a significant reduction of the model uncertainty. The implementation and results of this study will be presented and discussed in details.

  1. Efficacy of artificial tears for children xerophthalmia

    Directory of Open Access Journals (Sweden)

    Jie Yang

    2016-03-01

    Full Text Available AIM:To observe the efficacy and safety of artificial tears for children xerophthalmia.METHODS:Fifty-eight cases with 116 eyes were diagnosed as xerophthalmia by tear break-up time(BUT, Schirmer Ⅰ test(SⅠt, tear meniscus height, corneal staining, meibomian gland function test and were given artificial tears therapy for 1mo. Then the aforementioned tests were conducted again for statistical analysis.RESULTS:The mean BUT of all the children before treatments was 6.03±1.19s, SⅠt was 7.67±2.32mm/5min, tear meniscus height was 0.20±0.02mm, corneal staining was 1.02±0.13 scores and meibomian gland function was 2.45±0.86 scores. Sixty-two eyes in 31 cases were the lipid-deficient type, 40 eyes in 20 cases were aqueous-deficient type, and 14 eyes in 7 cases were other types. According to their types, corresponding artificial tears therapy was given. At 1mo after treatments, the clinical symptoms were improved significantly. BUT was 13.72±1.83s, SⅠt was 12.38±3.64mm/5min, tear meniscus height was 0.36±0.08mm, corneal fluorescein staining was 0.03±0.24 scores and meibomian gland function was 1.57±0.93 scores. Compared with those before treatments, the difference of each observed indicators was statistically significant(PCONCLUSION:Artificial tears treatment for children xerophthalmia is safe and effective.

  2. Neoclassical tearing modes in a tokamak

    International Nuclear Information System (INIS)

    Hahm, T.S.

    1988-08-01

    Linear tearing instability is studied in the banana collisionality regime in tokamak geometry. Neoclassical effects produce significant modifications of Ohm's law and the vorticity equation so that the growth rate of tearing modes driven by Δ' is dramatically reduced compared to the usual resistive MHD value. Consequences of this result, regarding the presence of pressure-gradient-driven neoclassical resistive interchange instabilities and the evolution of magnetic islands in the Rutherford regime, are discussed. 10 refs

  3. Process Parameter Identification in Thin Film Flows Driven by a Stretching Surface

    Directory of Open Access Journals (Sweden)

    Satyananda Panda

    2014-01-01

    Full Text Available The flow of a thin liquid film over a heated stretching surface is considered in this study. Due to a potential nonuniform temperature distribution on the stretching sheet, a temperature gradient occurs in the fluid which produces surface tension gradient at the free surface of the thin film. As a result, the free surface deforms and these deformations are advected by the flow in the stretching direction. This work focuses on the inverse problem of reconstructing the sheet temperature distribution and the sheet stretch rate from observed free surface variations. This work builds on the analysis of Santra and Dandapat (2009 who, based on the long-wave expansion of the Navier-Stokes equations, formulate a partial differential equation which describes the evolution of the thickness of a film over a nonisothermal stretched surface. In this work, we show that after algebraic manipulation of a discrete form of the governing equations, it is possible to reconstruct either the unknown temperature field on the sheet and hence the resulting heat transfer or the stretching rate of the underlying surface. We illustrate the proposed methodology and test its applicability on a range of test problems.

  4. The Relationship Between Tear Ferning Patterns and Non-invasive Tear Break-up Time in Normal Asian Population.

    Science.gov (United States)

    Sharanjeet-Kaur; Ho, Chien Yee; Mutalib, Haliza Abdul; Ghazali, Ahmad Rohi

    2016-01-01

    To investigate the relationship between tear ferning patterns (TFP) and non-invasive tear break-up time (NIBUT) in normal Asian subjects. One hundred and forty-five adults with no ocular surface disorders were recruited. TFP and NIBUT were determined. Tears were collected using a capillary tube and allowed to air dry at room temperature for 10min. TFP was later observed using a light microscope and classified according to Rolando's classification. Measurement for NIBUT was obtained using a Tearscope with the slit lamp magnification. It was found that there is no significant difference between gender in TFP (Z=-1.77, P>.05) and NIBUT (Z=-1.475, P>.05). There is also no significant difference between Malay, Chinese, Indian, and other races in TFP, (H(3)=4.85, P>.05) and NIBUT (H(3)=2.18, P>.05). However, there is a significant difference between age groups of 20-29, 30-39, 40-49,and 50-60 years old in both TFP (H(3)=28.25, P<.01) and NIBUT (H(3)=36.50, P<.001). Spearman's correlation showed there was a significant relationship between TFP and NIBUT (r=-0.55, P<.001), age and NIBUT (r=-0.50, P<.001), age and TFP (r=0.41, P<.001), McMonnies score and NIBUT (r=-0.40, P<.001), McMonnies score and TFP (r=0.31, P<.001), as well as age and McMonnies score (r=0.52, P<.001). TFP and NIBUT was age dependent but not gender and race dependent. Older subjects had higher grade of TFP and McMonnies questionnaire score but lower NIBUT value. TFP and NIBUT can be used to assess the tear film quality. Copyright © 2015 Spanish General Council of Optometry. Published by Elsevier Espana. All rights reserved.

  5. Effects of Processing Parameters on Surface Roughness of Additive Manufactured Ti-6Al-4V via Electron Beam Melting

    Science.gov (United States)

    Sin, Wai Jack; Nai, Mui Ling Sharon; Wei, Jun

    2017-01-01

    As one of the powder bed fusion additive manufacturing technologies, electron beam melting (EBM) is gaining more and more attention due to its near-net-shape production capacity with low residual stress and good mechanical properties. These characteristics also allow EBM built parts to be used as produced without post-processing. However, the as-built rough surface introduces a detrimental influence on the mechanical properties of metallic alloys. Thereafter, understanding the effects of processing parameters on the part’s surface roughness, in turn, becomes critical. This paper has focused on varying the processing parameters of two types of contouring scanning strategies namely, multispot and non-multispot, in EBM. The results suggest that the beam current and speed function are the most significant processing parameters for non-multispot contouring scanning strategy. While for multispot contouring scanning strategy, the number of spots, spot time, and spot overlap have greater effects than focus offset and beam current. The improved surface roughness has been obtained in both contouring scanning strategies. Furthermore, non-multispot contouring scanning strategy gives a lower surface roughness value and poorer geometrical accuracy than the multispot counterpart under the optimized conditions. These findings could be used as a guideline for selecting the contouring type used for specific industrial parts that are built using EBM. PMID:28937638

  6. Investigation of the influence of pretreatment parameters on the surface characteristics of amorphous metal for use in power industry

    Science.gov (United States)

    Nieroda, Jolanta; Rybak, Andrzej; Kmita, Grzegorz; Sitarz, Maciej

    2018-05-01

    Metallic glasses are metallic materials, which exhibit an amorphous structure. These are mostly three or more component alloys, and some of them are magnetic metals. Materials of this kind are characterized by high electrical resistivity and at the same time exhibit very good magnetic properties (e.g. low-magnetization loss). The above mentioned properties are very useful in electrical engineering industry and this material is more and more popular as a substance for high-efficiency electrical devices production. This industry area is still evolving, and thus even higher efficiency of apparatus based on amorphous material is expected. A raw material must be carefully investigated and characterized before the main production process is started. Presented work contains results of complementary examination of amorphous metal Metglas 2605. Studies involve two ways to obtain clean and oxidized surface with high reactivity, namely degreasing followed by annealing process and plasma treatment. The amorphous metal parameters were examined by means of several techniques: surface free energy (SFE) measurements by sessile drop method, X-ray Photoelectron Spectroscopy (XPS), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and both ex situ and in situ Raman spectroscopy. Additionally, influence of plasma parameters on wetting properties were optimized in systematic way with Design of Experiments (DOE) method. A wide range of used methods allow to fully investigate the amorphous metal material during preliminary preparation of surface. Obtained results provide information about appropriate parameters that should be applied in order to obtain highly reactive surface with functional oxide layer on it.

  7. Thermal effects on tearing mode saturation

    International Nuclear Information System (INIS)

    Kim, J.S.; Chu, M.S.; Greene, J.M.

    1988-01-01

    The effect of geometry on tearing modes, saturated states of tearing modes, and the thermal effect on tearing modes are presented. The configuration of current and magnetic fields are quite different in slabs and in Tokamaks. However, for any magnetic island regardless of geometry and heating conditions, at island saturation the product of resistivity and current is the same at magnetic O and X lines. The temperature perturbation effect on the nonlinear development of tearing modes is investigated. Thermal conduction along the field lines is much faster than that in the perpendicular direction, and thus the temperature profile follows the island structure. Utilizing Spitzer's conductivity relation, the temperature perturbation is modelled as helical components of resistivity. For a usual tearing mode unstable Tokamak, where shear is positive, the islands continue to grow to a larger size when the islands are cooled. When they are heated, the island sizes are reduced. The temperature perturbation can induce islands even for equilibria stable with respect to tearing modes. Again, the islands appear when cooling takes place. The equilibria with the cooled islands show enhanced field line stochasticity, thus enhanced heat transport. Therefore, thermal instability can be directly related to pressure disruptions. (author)

  8. Tear film measurement by optical reflectometry technique

    Science.gov (United States)

    Lu, Hui; Wang, Michael R.; Wang, Jianhua; Shen, Meixiao

    2014-01-01

    Abstract. Evaluation of tear film is performed by an optical reflectometer system with alignment guided by a galvanometer scanner. The reflectometer system utilizes optical fibers to deliver illumination light to the tear film and collect the film reflectance as a function of wavelength. Film thickness is determined by best fitting the reflectance-wavelength curve. The spectral reflectance acquisition time is 15 ms, fast enough for detecting film thickness changes. Fast beam alignment of 1 s is achieved by the galvanometer scanner. The reflectometer was first used to evaluate artificial tear film on a model eye with and without a contact lens. The film thickness and thinning rate have been successfully quantified with the minimum measured thickness of about 0.3 μm. Tear films in human eyes, with and without a contact lens, have also been evaluated. A high-contrast spectral reflectance signal from the precontact lens tear film is clearly observed, and the thinning dynamics have been easily recorded from 3.69 to 1.31 μm with lipid layer thickness variation in the range of 41 to 67 nm. The accuracy of the measurement is better than ±0.58% of the film thickness at an estimated tear film refractive index error of ±0.001. The fiber-based reflectometer system is compact and easy to handle. PMID:24500519

  9. Tear ferning test in healthy dogs.

    Science.gov (United States)

    Oriá, Arianne P; Raposo, Ana Claudia S; Araújo, Nayone L L C; Lima, Felipe B; Masmali, Ali M

    2017-11-07

    To evaluate and compare three tear sampling methods using two grading scales for administering the tear ferning test (TFT) to healthy dogs. In total, 90 dogs (180 eyes) were subjected to tear sampling using millimetered strips, reused after the Schirmer tear test (STT) (Schirmer group, SG). Then, the dogs were subdivided into three groups according to sampling approach: micropipette (MPG), microcapillary (MCG), and Schirmer sample 2 (S2G). The collected tears were dried on a clean microscope glass slide at room temperature and humidity. The ferning patterns were observed under a polarized light microscope and classified according to the Rolando and Masmali grading scales. Although all three methods were feasible, the STT was easier to perform in clinical settings. Type I and Grade 1 were the most commonly observed (64.17% and 61.7%, respectively) regardless of collection method. There was no significant difference between the STT median values and the TFT classifications. The TFT is appropriate for dogs and can be performed using the three suggested sampling methods, with a higher frequency of Type I and Grade 1. Thus, it is possible to use both grading scales in the classification of tear ferning in dogs. © 2017 American College of Veterinary Ophthalmologists.

  10. Sonographic evaluation of digital annular pulley tears

    International Nuclear Information System (INIS)

    Martinoli, C.; Derchi, L.E.; Bianchi, S.; Garcia, J.F.; Nebiolo, M.

    2000-01-01

    Objective. To evaluate the sonographic (US) appearance of digital annular pulley (DAP) tears in high-level rock climbers. Design and patients. We performed a retrospective analysis of the US examinations of 16 high-level rock climbers with clinical signs of DAP lesions. MRI and surgical evaluation were performed in five and three patients respectively. The normal US and MRI appearances of DAP were evaluated in 40 and three normal fingers respectively. Results. Nine of 16 patients presented a DAP tear. In eight subjects (seven with complete tears involving the fourth finger and one the fifth finger), US diagnosis was based on the indirect sign of volar bowstringing of the flexor tendons. Injured pulleys were not appreciated by US. Tears concerned the A2 and A3 in six patients and the A3 and A4 in two patients. A2 pulley thickening and hypoechogenicity compatible with a partial tear was demonstrated in one patient. MRI and surgical data correlated well with the US findings. Four patients had tenosynovitis of the flexor tendons but no evidence of pulley disruption. US examinations of three patients were normal. In the healthy subjects US demonstrated DAP in 16 of 40 digits. Conclusion. US can diagnose DAP tears and correlates with the MRI and surgical data. Because of its low cost and non-invasiveness we suggest US as the first imaging modality in the evaluation of injuries of the digital pulley. (orig.)

  11. Sonographic evaluation of digital annular pulley tears

    Energy Technology Data Exchange (ETDEWEB)

    Martinoli, C.; Derchi, L.E. [Istituto di Radiologia, Universita di Genova, Genoa (Italy); Bianchi, S.; Garcia, J.F. [Dept. de Radiologie, Hopital Cantonal Universitaire de Geneve (Switzerland); Nebiolo, M. [Reparto Pronto Soccorso Medico, Pietra Ligure (Italy)

    2000-07-01

    Objective. To evaluate the sonographic (US) appearance of digital annular pulley (DAP) tears in high-level rock climbers. Design and patients. We performed a retrospective analysis of the US examinations of 16 high-level rock climbers with clinical signs of DAP lesions. MRI and surgical evaluation were performed in five and three patients respectively. The normal US and MRI appearances of DAP were evaluated in 40 and three normal fingers respectively. Results. Nine of 16 patients presented a DAP tear. In eight subjects (seven with complete tears involving the fourth finger and one the fifth finger), US diagnosis was based on the indirect sign of volar bowstringing of the flexor tendons. Injured pulleys were not appreciated by US. Tears concerned the A2 and A3 in six patients and the A3 and A4 in two patients. A2 pulley thickening and hypoechogenicity compatible with a partial tear was demonstrated in one patient. MRI and surgical data correlated well with the US findings. Four patients had tenosynovitis of the flexor tendons but no evidence of pulley disruption. US examinations of three patients were normal. In the healthy subjects US demonstrated DAP in 16 of 40 digits. Conclusion. US can diagnose DAP tears and correlates with the MRI and surgical data. Because of its low cost and non-invasiveness we suggest US as the first imaging modality in the evaluation of injuries of the digital pulley. (orig.)

  12. Magnetic resonance findings in skeletal muscle tears

    International Nuclear Information System (INIS)

    De Smet, A.A.

    1993-01-01

    Magnetic resonance (MR) images of skeletal muscle tears can clearly delineate the severity of muscle injury. Although MR imaging is seldom necessary in patients with acute musle trauma, it can be helpful in deciding on clinical management. The two major MR findings in acute muscle tears are deformity of the muscle and the presence of abnormal signal reflecting hemorrhage and edema. In acute tears, methemoglobin within the extravascular blood causes high-signal areas on both T1- and T2-weighted images. With partial tears, the blood may dissect in a distinctive linear pattern along the muscle bundles and fibers. As healing begins, the muscle signal diminishes, first on the T1-weighted images and then on the T2-weighted images. When there is residual abnormal signal on images obtained more than several months after the injury, it is presumed to represent hemorrhage from recurrent tears. In patients with a questionable history of a remote injury, the clinical presentation may be that of persistent pain or a soft tissue mass. In these cases MR imaging may identify the cause of the pain and can exclude a neoplasm by proving that the mass is a hypertrophied or retracted musle. Thus, MR imaging has a limited, but occasionally important role in selected patients with skeletal muscle tears. (orig.)

  13. Rotator cuff tear: A detailed update

    Directory of Open Access Journals (Sweden)

    Vivek Pandey

    2015-01-01

    Full Text Available Rotator cuff tear has been a known entity for orthopaedic surgeons for more than two hundred years. Although the exact pathogenesis is controversial, a combination of intrinsic factors proposed by Codman and extrinsic factors theorized by Neer is likely responsible for most rotator cuff tears. Magnetic resonance imaging remains the gold standard for the diagnosis of rotator cuff tears, but the emergence of ultrasound has revolutionized the diagnostic capability. Even though mini-open rotator cuff repair is still commonly performed, and results are comparable to arthroscopic repair, all-arthroscopic repair of rotator cuff tear is now fast becoming a standard care for rotator cuff repair. Appropriate knowledge of pathology and healing pattern of cuff, strong and biological repair techniques, better suture anchors, and gradual rehabilitation of postcuff repair have led to good to excellent outcome after repair. As the healing of degenerative cuff tear remains unpredictable, the role of biological agents such as platelet-rich plasma and stem cells for postcuff repair augmentation is still under evaluation. The role of scaffolds in massive cuff tear is also being probed.

  14. Sensitivity of surface roughness parameters to changes in the density of scanning points in multi-scale AFM studies. Application to a biomaterial surface

    International Nuclear Information System (INIS)

    Mendez-Vilas, A.; Bruque, J.M.; Gonzalez-Martin, M.L.

    2007-01-01

    In the field of biomaterials surfaces, the ability of the atomic force microscope (AFM) to access the surface structure at unprecedented spatial (vertical and lateral) resolution, is helping in a better understanding on how topography affects the overall interaction of biological cells with the material surface. Since cells in a wide range of sizes are in contact with the biomaterial surface, a quantification of the surface structure in such a wide range of dimensional scales is needed. With the advent of the AFM, this can be routinely done in the lab. In this work, we show that even when it is clear that such a scale-dependent study is needed, AFM maps of the biomaterial surface taken at different scanning lengths are not completely consistent when they are taken at the same scanning resolution, as it is usually done: AFM images of different scanning areas have different point-to-point physical distances. We show that this effect influences the quantification of the average (R a ) and rms (R q ) roughness parameters determined at different length scales. This is the first time this inconsistency is reported and should be taken into account when roughness is measured in this way. Since differences will be in general in the range of nanometres, this is especially interesting for those processes involving the interaction of the biomaterial surface with small biocolloids as bacteria, while this effect should not represent any problems for larger animal cells

  15. Determination of Optimal Parameters for Diffusion Bonding of Semi-Solid Casting Aluminium Alloy by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Kaewploy Somsak

    2015-01-01

    Full Text Available Liquid state welding techniques available are prone to gas porosity problems. To avoid this solid state bonding is usually an alternative of preference. Among solid state bonding techniques, diffusion bonding is often employed in aluminium alloy automotive parts welding in order to enhance their mechanical properties. However, there has been no standard procedure nor has there been any definitive criterion for judicious welding parameters setting. It is thus a matter of importance to find the set of optimal parameters for effective diffusion bonding. This work proposes the use of response surface methodology in determining such a set of optimal parameters. Response surface methodology is more efficient in dealing with complex process compared with other techniques available. There are two variations of response surface methodology. The one adopted in this work is the central composite design approach. This is because when the initial upper and lower bounds of the desired parameters are exceeded the central composite design approach is still capable of yielding the optimal values of the parameters that appear to be out of the initially preset range. Results from the experiments show that the pressing pressure and the holding time affect the tensile strength of jointing. The data obtained from the experiment fits well to a quadratic equation with high coefficient of determination (R2 = 94.21%. It is found that the optimal parameters in the process of jointing semi-solid casting aluminium alloy by using diffusion bonding are the pressing pressure of 2.06 MPa and 214 minutes of the holding time in order to achieve the highest tensile strength of 142.65 MPa

  16. Shaping surface of palladium nanospheres through the control of reaction parameters

    International Nuclear Information System (INIS)

    Wang Lianmeng; Tan Enzhong; Guo Lin; Wang Lihua; Han Xiaodong

    2011-01-01

    Solid, cracked, and flower-shaped surfaces of palladium nanospheres with high yields and good uniformity were successfully prepared by a wet chemical method. On the basis of the experimental data, the same size of palladium nanosphere with different surface morphologies can be regulated only by changing the amount of ammonium hydroxide and reductant in one experimental system. The as-prepared products were studied by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and x-ray diffraction (XRD). In addition, surface-enhanced Raman scattering (SERS) spectra on the as-prepared different surface of palladium nanospheres exhibit high activity towards p-aminothiophenol (PATP) detection, and the result further reveals that the predominance of the a1 vibration mode in the SERS spectra via an electromagnetic (EM) mechanism is significant.

  17. A Mathematical Method to Calculate Tumor Contact Surface Area: An Effective Parameter to Predict Renal Function after Partial Nephrectomy.

    Science.gov (United States)

    Hsieh, Po-Fan; Wang, Yu-De; Huang, Chi-Ping; Wu, Hsi-Chin; Yang, Che-Rei; Chen, Guang-Heng; Chang, Chao-Hsiang

    2016-07-01

    We proposed a mathematical formula to calculate contact surface area between a tumor and renal parenchyma. We examined the applicability of using contact surface area to predict renal function after partial nephrectomy. We performed this retrospective study in patients who underwent partial nephrectomy between January 2012 and December 2014. Based on abdominopelvic computerized tomography or magnetic resonance imaging, we calculated the contact surface area using the formula (2*π*radius*depth) developed by integral calculus. We then evaluated the correlation between contact surface area and perioperative parameters, and compared contact surface area and R.E.N.A.L. (Radius/Exophytic/endophytic/Nearness to collecting system/Anterior/Location) score in predicting a reduction in renal function. Overall 35, 26 and 45 patients underwent partial nephrectomy with open, laparoscopic and robotic approaches, respectively. Mean ± SD contact surface area was 30.7±26.1 cm(2) and median (IQR) R.E.N.A.L. score was 7 (2.25). Spearman correlation analysis showed that contact surface area was significantly associated with estimated blood loss (p=0.04), operative time (p=0.04) and percent change in estimated glomerular filtration rate (p contact surface area and R.E.N.A.L. score independently affected percent change in estimated glomerular filtration rate (p contact surface area was a better independent predictor of a greater than 10% change in estimated glomerular filtration rate compared to R.E.N.A.L. score (AUC 0.86 vs 0.69). Using this simple mathematical method, contact surface area was associated with surgical outcomes. Compared to R.E.N.A.L. score, contact surface area was a better predictor of functional change after partial nephrectomy. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  18. Experimental investigation into effect of cutting parameters on surface integrity of hardened tool steel

    Science.gov (United States)

    Bashir, K.; Alkali, A. U.; Elmunafi, M. H. S.; Yusof, N. M.

    2018-04-01

    Recent trend in turning hardened materials have gained popularity because of its immense machinability benefits. However, several machining processes like thermal assisted machining and cryogenic machining have reveal superior machinability benefits over conventional dry turning of hardened materials. Various engineering materials have been studied. However, investigations on AISI O1 tool steel have not been widely reported. In this paper, surface finish and surface integrity dominant when hard turning AISI O1 tool steel is analysed. The study is focused on the performance of wiper coated ceramic tool with respect to surface roughness and surface integrity of hardened tool steel. Hard turned tool steel was machined at varying cutting speed of 100, 155 and 210 m/min and feed rate of 0.05, 0.125 and 0.20mm/rev. The depth of cut of 0.2mm was maintained constant throughout the machining trials. Machining was conducted using dry turning on 200E-axis CNC lathe. The experimental study revealed that the surface finish is relatively superior at higher cutting speed of 210m/min. The surface finish increases when cutting speed increases whereas surface finish is generally better at lower feed rate of 0.05mm/rev. The experimental study conducted have revealed that phenomena such as work piece vibration due to poor or improper mounting on the spindle also contributed to higher surface roughness value of 0.66Ra during turning at 0.2mm/rev. Traces of white layer was observed when viewed with optical microscope which shows evidence of cutting effects on the turned work material at feed rate of 0.2 rev/min

  19. Effect of Physical Property and Surface Morphology of Copper Foil at Electrodeposition Parameter

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Tae Gyu; Park, Il Song; Lee, Man Hyung; Seol, Kyeong Won [Chonbuk National University, Jeonju (Korea, Republic of)

    2014-06-15

    The effect of additives, current density and plated temperature on the surface morphology and physical property, during copper electrodeposition on polyimide (PI) film was investigated. Two kinds of additives, Cl and leveler (additive B), were used in this study. Electrochemical experiments were performed in conjunction with SEM, XRD and four-point probe to characterize the morphology and mechanical characteristics of copper electrodeposited in the presence of the additives. The surface roughness, crystal growth orientation and resistivity was controlled by the concentration of additive B. High resistivity and lower peel strength were observed on the surface of the copper layer electroplated in the electrolyte without additive B. However, a uniform surface, lower resistivity and high flexibility were obtained with a combination of 20 ppm Cl and 100 ppm additive B. Large particles were observed on the surface of the copper layer electroplated using a current density of 25 mA/cm{sup 2}, but a uniform surface and lower resistivity were obtained using a current density of 10 mA/cm{sup 2}. One of the required important properties of FCCL is flexibility of the copper foil. High flexibility of FCCL was obtained at a low current density, rather than a high current density. Moreover, a reasonable current density is 20 mA/cm{sup 2}, considering the productivity and mechanical properties of copper foil.

  20. A summary of the sources of input parameter values for the Waste Isolation Pilot Plant final porosity surface calculations

    International Nuclear Information System (INIS)

    Butcher, B.M.

    1997-08-01

    A summary of the input parameter values used in final predictions of closure and waste densification in the Waste Isolation Pilot Plant disposal room is presented, along with supporting references. These predictions are referred to as the final porosity surface data and will be used for WIPP performance calculations supporting the Compliance Certification Application to be submitted to the U.S. Environmental Protection Agency. The report includes tables and list all of the input parameter values, references citing their source, and in some cases references to more complete descriptions of considerations leading to the selection of values

  1. A summary of the sources of input parameter values for the Waste Isolation Pilot Plant final porosity surface calculations

    Energy Technology Data Exchange (ETDEWEB)

    Butcher, B.M.

    1997-08-01

    A summary of the input parameter values used in final predictions of closure and waste densification in the Waste Isolation Pilot Plant disposal room is presented, along with supporting references. These predictions are referred to as the final porosity surface data and will be used for WIPP performance calculations supporting the Compliance Certification Application to be submitted to the U.S. Environmental Protection Agency. The report includes tables and list all of the input parameter values, references citing their source, and in some cases references to more complete descriptions of considerations leading to the selection of values.

  2. Effect of Irradiation Parameters on Morphology of Polishing DF2 (AISI-O1 Surface by Nd:YAG Laser

    Directory of Open Access Journals (Sweden)

    Wei Guo

    2007-01-01

    Full Text Available Pulse Nd:YAG laser was used to polish DF2 cold work steel. Influence of irradiation parameters on the 3D surface morphology was studied by 3D profilometer, scanning electron microscopy (SEM, and atomic force microscope (AFM. Results among the tests showed when DF2 specimens were irradiated with parameters of (i laser input energy P=1 J, (ii pulse feedrate=300 mm/min, (iii pulse duration (PD =3 milliseconds, and (iv pulse frequency f=20∼25 Hz, laser polishing of DF2 cold work steel seemed to be successful.

  3. The Efficacy of Diquafosol Ophthalmic Solution in Non-Sjögren and Sjögren Syndrome Dry Eye Patients Unresponsive to Artificial Tear.

    Science.gov (United States)

    Jeon, Hyun Sun; Hyon, Joon Young

    2016-09-01

    This study evaluates the efficacy of 3% diquafosol tetrasodium ophthalmic solution in Sjögren's syndrome (SS) and non-SS dry eye patients unresponsive to conventional artificial tear. This retrospective study included 38 dry eye patients (11 with SS and 27 with non-SS) who were treated with 3% diquafosol due to lack of response to artificial tear treatment for more than 3 months. Signs such as tear film break-up time (TBUT), Schirmer-I test, and total ocular staining score (OSS), which consisted of corneal OSS and conjunctival OSS, were evaluated at baseline and the first visit after treatment. Symptoms were quantified using visual analog scale (VAS) and ocular surface disease index (OSDI) scores. Changes of parameters after treatment in all the patients and differences of changes in SS and non-SS were evaluated. In total population, total OSS and corneal OSS improved average 6 weeks after diquafosol treatment (all P < 0.05, paired t-test), although conjunctival OSS had no improvement. TBUT increased after treatment (P = 0.036), while Schirmer-I test, OSDI, and VAS showed no improvement. With respect to comparisons, total and corneal OSS improved in non-SS patients and TBUT improved in SS patients (all P < 0.05). Three percent diquafosol tetrasodium treatment could be considered as an additive or substitute treatment when artificial tear treatment is insufficient, as it improved OSS and TBUT. This study also demonstrated that diquafosol treatment is beneficial for TBUT improvement in SS, while it is beneficial for OSS improvement in non-SS dry eye patients.

  4. Neoclassical tearing mode stabilization by ECCD in ITER

    International Nuclear Information System (INIS)

    Giruzzi, G.; Zabiego, M.

    2001-01-01

    A dynamic model, based on a 3-D Fokker-Planck code coupled to the island evolution equations, is used to evaluate the feasibility of active control of Neoclassical Tearing modes by Electron Cyclotron Current Drive (ECCD) in International Thermonuclear Experimental Reactor (ITER). The parameters of the present version of ITER, i.e., RTO/RC ITER (IAM option) are used. Both m=3, n=2 and m=2, n=1 modes are considered. It is shown that an Electron Cyclotron wave system at 140 GHz, with toroidally steerable antennas, can stabilize both modes simultaneously if a power ≥30 MW is available

  5. Bacterial growth on surfaces: Automated image analysis for quantification of growth rate-related parameters

    DEFF Research Database (Denmark)

    Møller, S.; Sternberg, Claus; Poulsen, L. K.

    1995-01-01

    species-specific hybridizations with fluorescence-labelled ribosomal probes to estimate the single-cell concentration of RNA. By automated analysis of digitized images of stained cells, we determined four independent growth rate-related parameters: cellular RNA and DNA contents, cell volume......, and the frequency of dividing cells in a cell population. These parameters were used to compare physiological states of liquid-suspended and surfacegrowing Pseudomonas putida KT2442 in chemostat cultures. The major finding is that the correlation between substrate availability and cellular growth rate found...

  6. Effect of Surface Texturing Parameters on the Lubrication Characteristics of an Axial Piston Pump Valve Plate

    Directory of Open Access Journals (Sweden)

    Zhaoqiang Wang

    2018-05-01

    Full Text Available In this article, a geometrical model of different microtextures is established for an axial piston pump valve plate. A finite differential method was used to solve the Reynolds equation for the oil film thickness and pressure, which were simulated under different microtextures. The influence of microtexture shape and structure on performance was studied and optimal parameters sought. Different convergence gaps are formed by different microtexture radii, and they produce different hydrodynamic effects. The lubrication characteristics of the valve plate are better when a microtexture is used and are influenced by the type of microtexture. We reached the following conclusions: (1 The lubrication characteristics of the valve plate are influenced by different microtexture parameters and can be improved by optimizing the microtexture parameters; (2 There is an optimal parameter combination when adding microtexture with three shapes (spherical, cylindrical and square and the optimal dimensionless oil film pressure lubrication characteristics can be obtained; (3 The degree of improvement in the dimensionless oil film pressure lubrication characteristics was (listed from highest to lowest: micro-hemispherical texture > micro-cylindrical texture > micro-square texture.

  7. Textural parameters distribution in sediments surface of the Uruguay river background between km 221 and 254

    International Nuclear Information System (INIS)

    Capeluto, W.; Campos, T. de los

    2010-01-01

    The aim of this paper is to analyze the distribution of textural statistical parameters and spatial variation in the morphology of the sediment areas. The geology of the area comprises alluvial and alluvial deposits of variable thicknesses overlying deposits of Fray Bent os, Salto and Guichon formations that occasionally emerge in the river bed

  8. Influence of Cutting Parameters on the Surface Roughness and Hole Diameter of Drilling Making Parts of Alluminium Alloy

    Directory of Open Access Journals (Sweden)

    Andrius Stasiūnas

    2013-02-01

    Full Text Available The article researches the drilling process of an aluminium alloy. The paper is aimed at analyzing the influence of cutting speed, feed and hole depth considering hole diameter and hole surface roughness of aluminum alloy 6082 in the dry drilling process and at making empirical formulas for cutting parameters. The article also describes experimental techniques and equipment, tools and measuring devices. Experimental studies have been carried out using different cutting parameters. The obtained results have been analyzed using computer software. According to the existing techniques for measuring, surface roughness and hole diameters have been measured, empirical models have been created and the results of the conducted experiments have been inspected. The findings and recommendations are presented at the end of the work.Artcile in Lithuanian

  9. Optimization of Surface Roughness Parameters of Al-6351 Alloy in EDC Process: A Taguchi Coupled Fuzzy Logic Approach

    Science.gov (United States)

    Kar, Siddhartha; Chakraborty, Sujoy; Dey, Vidyut; Ghosh, Subrata Kumar

    2017-10-01

    This paper investigates the application of Taguchi method with fuzzy logic for multi objective optimization of roughness parameters in electro discharge coating process of Al-6351 alloy with powder metallurgical compacted SiC/Cu tool. A Taguchi L16 orthogonal array was employed to investigate the roughness parameters by varying tool parameters like composition and compaction load and electro discharge machining parameters like pulse-on time and peak current. Crucial roughness parameters like Centre line average roughness, Average maximum height of the profile and Mean spacing of local peaks of the profile were measured on the coated specimen. The signal to noise ratios were fuzzified to optimize the roughness parameters through a single comprehensive output measure (COM). Best COM obtained with lower values of compaction load, pulse-on time and current and 30:70 (SiC:Cu) composition of tool. Analysis of variance is carried out and a significant COM model is observed with peak current yielding highest contribution followed by pulse-on time, compaction load and composition. The deposited layer is characterised by X-Ray Diffraction analysis which confirmed the presence of tool materials on the work piece surface.

  10. Quantitative analysis of tear film fluorescence and discomfort during tear film instability and thinning.

    Science.gov (United States)

    Begley, Carolyn; Simpson, Trefford; Liu, Haixia; Salvo, Eliza; Wu, Ziwei; Bradley, Arthur; Situ, Ping

    2013-04-12

    The purpose of this study was to test the association between tear film fluorescence changes during tear break-up (TBU) or thinning and the concurrent ocular sensory response. Sixteen subjects kept one eye open as long as possible (MBI), indicated their discomfort level continuously, and rated ocular sensations of irritation, stinging, burning, pricking, and cooling using visual analog scales (VAS). Fluorescence of the tear film was quantified by a pixel-based analysis of the median pixel intensity (PI), TBU, and percentage of dark pixels (DarkPix) over time. A cutoff of 5% TBU was used to divide subjects into either break-up (BU) or minimal break-up (BUmin) groups. Tear film fluorescence decreased (median PI) and the percentage of TBU and DarkPix increased in all trials, with the rate significantly greater in the BU than the BUmin group (Mann-Whitney U test, P film thinning best explains decreasing tear film fluorescence during trials. This was highly correlated with increasing ocular discomfort, suggesting that both tear film thinning and TBU stimulate underlying corneal nerves, although TBU produced more rapid stimulation. Slow increases in tear film hyperosmolarity may cause the gradual increase in discomfort during slow tear film thinning, whereas the sharp increases in discomfort during TBU suggest a more complex stimulus.

  11. Simulation optimization of filament parameters for uniform depositions of diamond films on surfaces of ultra-large circular holes

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xinchang, E-mail: wangxinchangz@163.com; Shen, Xiaotian; Sun, Fanghong; Shen, Bin

    2016-12-01

    Highlights: • A verified simulation model using a novel filament arrangement is constructed. • Influences of filament parameters are clarified. • A coefficient between simulated and experimental results is proposed. • Orthogonal simulations are adopted to optimize filament parameters. • A general filament arrangement suitable for different conditions is determined. - Abstract: Chemical vapor deposition (CVD) diamond films have been widely applied as protective coatings on varieties of anti-frictional and wear-resistant components, owing to their excellent mechanical and tribological properties close to the natural diamond. In applications of some components, the inner hole surface will serve as the working surface that suffers severe frictional or erosive wear. It is difficult to realize uniform depositions of diamond films on surfaces of inner holes, especially ultra-large inner holes. Adopting a SiC compact die with an aperture of 80 mm as an example, a novel filament arrangement with a certain number of filaments evenly distributed on a circle is designed, and specific effects of filament parameters, including the filament number, arrangement direction, filament temperature, filament diameter, circumradius and the downward translation, on the substrate temperature distribution are studied by computational fluid dynamics (CFD) simulations based on the finite volume method (FVM), adopting a modified computational model well consistent with the actual deposition environment. Corresponding temperature measurement experiments are also conducted to verify the rationality of the computational model. From the aspect of depositing uniform boron-doped micro-crystalline, undoped micro-crystalline and undoped fine-grained composite diamond (BDM-UMC-UFGCD) film on such the inner hole surface, filament parameters as mentioned above are accurately optimized and compensated by orthogonal simulations. Moreover, deposition experiments adopting compensated optimized

  12. The use of interpractive graphic displays for interpretation of surface design parameters

    Science.gov (United States)

    Talcott, N. A., Jr.

    1981-01-01

    An interactive computer graphics technique known as the Graphic Display Data method has been developed to provide a convenient means for rapidly interpreting large amounts of surface design data. The display technique should prove valuable in such disciplines as aerodynamic analysis, structural analysis, and experimental data analysis. To demonstrate the system's features, an example is presented of the Graphic Data Display method used as an interpretive tool for radiation equilibrium temperature distributions over the surface of an aerodynamic vehicle. Color graphic displays were also examined as a logical extension of the technique to improve its clarity and to allow the presentation of greater detail in a single display.

  13. Prediction of surface roughness in turning of Ti-6Al-4V using cutting parameters, forces and tool vibration

    Science.gov (United States)

    Sahu, Neelesh Kumar; Andhare, Atul B.; Andhale, Sandip; Raju Abraham, Roja

    2018-04-01

    Present work deals with prediction of surface roughness using cutting parameters along with in-process measured cutting force and tool vibration (acceleration) during turning of Ti-6Al-4V with cubic boron nitride (CBN) inserts. Full factorial design is used for design of experiments using cutting speed, feed rate and depth of cut as design variables. Prediction model for surface roughness is developed using response surface methodology with cutting speed, feed rate, depth of cut, resultant cutting force and acceleration as control variables. Analysis of variance (ANOVA) is performed to find out significant terms in the model. Insignificant terms are removed after performing statistical test using backward elimination approach. Effect of each control variables on surface roughness is also studied. Correlation coefficient (R2 pred) of 99.4% shows that model correctly explains the experiment results and it behaves well even when adjustment is made in factors or new factors are added or eliminated. Validation of model is done with five fresh experiments and measured forces and acceleration values. Average absolute error between RSM model and experimental measured surface roughness is found to be 10.2%. Additionally, an artificial neural network model is also developed for prediction of surface roughness. The prediction results of modified regression model are compared with ANN. It is found that RSM model and ANN (average absolute error 7.5%) are predicting roughness with more than 90% accuracy. From the results obtained it is found that including cutting force and vibration for prediction of surface roughness gives better prediction than considering only cutting parameters. Also, ANN gives better prediction over RSM models.

  14. Stabilization of tearing modes to suppress major disruptions in tokamaks

    International Nuclear Information System (INIS)

    Holmes, J.A.; Carreras, B.; Hicks, H.R.; Lynch, S.J.; Waddell, B.V.

    1979-02-01

    It is shown, for q-profiles which lead to a disruption, that the control of the amplitude of the 2/1 tearing mode avoids the disruption. Q-profiles measured in T-4 and PLT before a major disruption were studied. Two methods of controlling the 2/1 mode amplitude have been considered: (1) Feedback stabilization with the feedback signal locked in phase with the 2/1 mode. (2) Heating slightly outside the q = 2 surface. In both cases it is only necessary to decrease the 2/1 mode amplitude to suppress the disruption. It is not always necessary to stabilize the unstable modes fully

  15. The influence of non-polar lipids on tear film dynamics

    KAUST Repository

    Bruna, M.

    2014-04-04

    © 2014 Cambridge University Press. In this paper we examine the effect that physiological non-polar lipids, residing on the surface of an aqueous tear film, have on the film evolution. In our model we track the evolution of the thickness of the non-polar lipid layer, the thickness of the aqueous layer and the concentration of polar lipids which reside at the interface between the two. We also utilise a force balance in the non-polar lipid layer in order to determine its velocity. We show how to obtain previous models in the literature from our model by making particular choices of the parameters. We see the formation of boundary layers in some of these submodels, across which the concentration of polar lipid and the non-polar lipid velocity and film thickness vary. We solve our model numerically for physically realistic parameter values, and we find that the evolution of the aqueous layer and the polar lipid layer are similar to that described by previous authors. However, there are interesting dynamics for the non-polar lipid layer. The effects of altering the key parameters are highlighted and discussed. In particular, we see that the Marangoni number plays a key role in determining how far over the eye the non-polar lipid spreads.

  16. [Energy dispersive spectrum analysis of surface compositions of selective laser melting cobalt-chromium alloy fabricated by different processing parameters].

    Science.gov (United States)

    Qian, Liang; Zeng, Li; Wei, Bin; Gong, Yao

    2015-06-01

    To fabricate selective laser melting cobalt-chromium alloy samples by different processing parameters, and to analyze the changes of energy dispersive spectrum(EDS) on their surface. Nine groups were set up by orthogonal experimental design according to different laser powers,scanning speeds and powder feeding rates(laser power:2500-3000 W, scanning speed: 5-15 mm/s, powder feeding rate: 3-6 r/min). Three cylinder specimens(10 mm in diameter and 3 mm in thickness) were fabricated in each group through Rofin DL 035Q laser cladding system using cobalt-chromium alloy powders which were developed independently by our group.Their surface compositions were then measured by EDS analysis. Results of EDS analysis of the 9 groups fabricated by different processing parameters(Co:62.98%-67.13%,Cr:25.56%-28.50%,Si:0.49%-1.23%) were obtained. They were similar to the compositions of cobalt-chromium alloy used in dental practice. According to EDS results, the surface compositions of the selective laser melting cobalt-chromium alloy samples are stable and controllable, which help us gain a preliminary sight into the range of SLM processing parameters. Supported by "973" Program (2012CB910401) and Research Fund of Science and Technology Committee of Shanghai Municipality (12441903001 and 13140902701).

  17. Optimisation of process parameters on thin shell part using response surface methodology (RSM) and genetic algorithm (GA)

    Science.gov (United States)

    Faiz, J. M.; Shayfull, Z.; Nasir, S. M.; Fathullah, M.; Hazwan, M. H. M.

    2017-09-01

    This study conducts the simulation on optimisation of injection moulding process parameters using Autodesk Moldflow Insight (AMI) software. This study has applied some process parameters which are melt temperature, mould temperature, packing pressure, and cooling time in order to analyse the warpage value of the part. Besides, a part has been selected to be studied which made of Polypropylene (PP). The combination of the process parameters is analysed using Analysis of Variance (ANOVA) and the optimised value is obtained using Response Surface Methodology (RSM). The RSM as well as Genetic Algorithm are applied in Design Expert software in order to minimise the warpage value. The outcome of this study shows that the warpage value improved by using RSM and GA.

  18. Danish translation and validation of the International Skin Tear Advisory Panel Skin Tear Classification System

    DEFF Research Database (Denmark)

    Skiveren, J; Bermark, S; LeBlanc, K

    2015-01-01

    OBJECTIVE: The aim of this study was to translate, validate and establish reliability of the International Skin Tear Classification System in Danish. METHOD: Phase 1 of the project involved the translation of the International Skin Tear Advisory Panel (ISTAP) Skin Tear Classification System......) and social and health-care assistants (non-RN) from both primary health care and a Danish university hospital in Copenhagen. Thirty photographs, with equal representation of the three types of skin tears, were selected to test validity. The photographs chosen were those originally used for internal...... and external validation by the ISTAP group. The subjects were approached in their place of work and invited to participate in the study and to attend an educational session related to skin tears. RESULTS: The Danish translation of the ISTAP classification system was tested on 270 non-wound specialists...

  19. Impact of Optimized Land Surface Parameters on the Land-Atmosphere Coupling in WRF Simulations of Dry and Wet Extremes

    Science.gov (United States)

    Kumar, S.; Santanello, J. A.; Peters-Lidard, C. D.; Harrison, K.

    2011-12-01

    Land-atmosphere (L-A) interactions play a critical role in determining the diurnal evolution of both planetary boundary layer (PBL) and land surface temperature and moisture budgets, as well as controlling feedbacks with clouds and precipitation that lead to the persistence of dry and wet regimes. Recent efforts to quantify the strength of L-A coupling in prediction models have produced diagnostics that integrate across both the land and PBL components of the system. In this study, we examine the impact of improved specification of land surface states, anomalies, and fluxes on coupled WRF forecasts during the summers of extreme dry (2006) and wet (2007) conditions in the U.S. Southern Great Plains. The improved land initialization and surface flux parameterizations are obtained through the use of a new optimization and uncertainty module in NASA's Land Information System (LIS-OPT), whereby parameter sets are calibrated in the Noah land surface model and classified according to the land cover and soil type mapping of the observations and the full domain. The impact of the calibrated parameters on the a) spinup of land surface states used as initial conditions, and b) heat and moisture fluxes of the coupled (LIS-WRF) simulations are then assessed in terms of ambient weather, PBL budgets, and precipitation along with L-A coupling diagnostics. In addition, the sensitivity of this approach to the period of calibration (dry, wet, normal) is investigated. Finally, tradeoffs of computational tractability and scientific validity (e.g.,. relating to the representation of the spatial dependence of parameters) and the feasibility of calibrating to multiple observational datasets are also discussed.

  20. Superior glenoid inclination and rotator cuff tears.

    Science.gov (United States)

    Chalmers, Peter N; Beck, Lindsay; Granger, Erin; Henninger, Heath; Tashjian, Robert Z

    2018-03-23

    The objectives of this study were to determine whether glenoid inclination (1) could be measured accurately on magnetic resonance imaging (MRI) using computed tomography (CT) as a gold standard, (2) could be measured reliably on MRI, and (3) whether it differed between patients with rotator cuff tears and age-matched controls without evidence of rotator cuff tears or glenohumeral osteoarthritis. In this comparative retrospective radiographic study, we measured glenoid inclination on T1 coronal MRI corrected into the plane of the scapula. We determined accuracy by comparison with CT and inter-rater reliability. We compared glenoid inclination between patients with full-thickness rotator cuff tears and patients aged >50 years without evidence of a rotator cuff tear or glenohumeral arthritis. An a priori power analysis determined adequate power to detect a 2° difference in glenoid inclination. (1) In a validation cohort of 37 patients with MRI and CT, the intraclass correlation coefficient was 0.877, with a mean difference of 0° (95% confidence interval, -1° to 1°). (2) For MRI inclination, the inter-rater intraclass correlation coefficient was 0.911. (3) Superior glenoid inclination was 2° higher (range, 1°-4°, P rotator cuff tear group of 192 patients than in the control cohort of 107 patients. Glenoid inclination can be accurately and reliably measured on MRI. Although superior glenoid inclination is statistically greater in those with rotator cuff tears than in patients of similar age without rotator cuff tears or glenohumeral arthritis, the difference is likely below clinical significance. Copyright © 2018 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  1. Surface peroneal nerve stimulation in lower limb hemiparesis : Effect on quantitative gait parameters

    NARCIS (Netherlands)

    Sheffler, Lynne R.; Taylor, Paul N.; Bailey, Stephanie Nogan; Gunzler, Douglas; Buurke, Jaap H.; Ijzerman, Maarten J.; Chae, John

    2015-01-01

    Objective: The objective of this study was to evaluate possible mechanisms for functional improvement and compare ambulation training with surface peroneal nerve stimulation vs. usual care via quantitative gait analysis. Design: This study is a randomized controlled clinical trial. Setting: The

  2. Internal oscillating current-sustained RF plasmas: Parameters, stability, and potential for surface engineering

    DEFF Research Database (Denmark)

    Ostrikov, K.; Tsakadze, E.L.; Tsakadze, Z.L.

    2005-01-01

    . Moreover, under certain conditions, the plasma becomes unstable due to spontaneous transitions between low-density (electrostatic, E) and high-density (electromagnetic, H) operating modes. Excellent uniformity of high-density plasmas makes the plasma reactor promising for various plasma processing...... applications and surface engineering. (c) 2005 Elsevier B.V. All rights reserved....

  3. Site specificity of biosphere parameter values in performance assessments of near-surface repositories

    International Nuclear Information System (INIS)

    Zeevaert, Th.; Volckaert, G.; Vandecasleele

    1993-01-01

    The contribution is dealing with the performance assessment model for near surface repositories in Belgium. It consists of four submodels called: site, aquifer, biosphere and dose. For some characteristic radionuclides, results of the study are shown for a typical site, and differences in doses assessed with the generic approach discussed. Shortcomings are indicated

  4. Analyzing the effect of cutting parameters on surface roughness and tool wear when machining nickel based hastelloy - 276

    International Nuclear Information System (INIS)

    Khidhir, Basim A; Mohamed, Bashir

    2011-01-01

    Machining parameters has an important factor on tool wear and surface finish, for that the manufacturers need to obtain optimal operating parameters with a minimum set of experiments as well as minimizing the simulations in order to reduce machining set up costs. The cutting speed is one of the most important cutting parameter to evaluate, it clearly most influences on one hand, tool life, tool stability, and cutting process quality, and on the other hand controls production flow. Due to more demanding manufacturing systems, the requirements for reliable technological information have increased. For a reliable analysis in cutting, the cutting zone (tip insert-workpiece-chip system) as the mechanics of cutting in this area are very complicated, the chip is formed in the shear plane (entrance the shear zone) and is shape in the sliding plane. The temperature contributed in the primary shear, chamfer and sticking, sliding zones are expressed as a function of unknown shear angle on the rake face and temperature modified flow stress in each zone. The experiments were carried out on a CNC lathe and surface finish and tool tip wear are measured in process. Machining experiments are conducted. Reasonable agreement is observed under turning with high depth of cut. Results of this research help to guide the design of new cutting tool materials and the studies on evaluation of machining parameters to further advance the productivity of nickel based alloy Hastelloy - 276 machining.

  5. Exploring topical anti-glaucoma medication effects on the ocular surface in the context of the current understanding of dry eye.

    Science.gov (United States)

    Wong, Aaron B C; Wang, Michael T M; Liu, Kevin; Prime, Zak J; Danesh-Meyer, Helen V; Craig, Jennifer P

    2018-07-01

    To assess tear film parameters, ocular surface characteristics, and dry eye symptomology in patients receiving topical anti-glaucoma medications. Thirty-three patients with a diagnosis of open angle glaucoma or ocular hypertension, receiving unilateral topical anti-glaucoma medication for at least 6 months, were recruited in a cross-sectional, investigator-masked, paired-eye comparison study. Tear film parameters, ocular surface characteristics, and dry eye symptomology of treated and fellow eyes were evaluated and compared. The mean ± SD age of the participants was 67 ± 12 years, and the mean ± SD treatment duration was 5.3 ± 4.4 years. Treated eyes had poorer non-invasive tear film breakup time (p = 0.03), tear film osmolarity (p = 0.04), bulbar conjunctival hyperaemia (p = 0.04), eyelid margin abnormality grade (p = 0.01), tear meniscus height (p = 0.03), and anaesthetised Schirmer value (p = 0.04) than fellow eyes. There were no significant differences in dry eye symptomology, meibomian gland assessments, and ocular surface staining between treated and fellow eyes (all p > 0.05). Adverse changes in tear film stability, tear osmolarity, conjunctival hyperaemia, and eyelid margins were observed in treated eyes. This suggests that inflammatory mechanisms may be implicated in the development of dry eye in patients receiving long term topical anti-glaucoma therapy. Copyright © 2018 Elsevier Inc. All rights reserved.

  6. PARAMETER DESIGN OF AN ELECTRO PNEUMATIC SYSTEM USING RESPONSE SURFACE METHODOLOGY

    OpenAIRE

    Rajakannu Amuthakkannan

    2014-01-01

    In the present scenario, more number of software based mechanical systems are coming with advanced technologies like embedded system control or computer system control for various industrial applications. Mechatronics is a popular technology in the evolutionary process of modern engineering automation system design. The ineffective parameter design in software based mechatronics system may produce the severe consequences in the application field, even there is a chance of accidents. So, caref...

  7. Predictive Models for Different Roughness Parameters During Machining Process of Peek Composites Using Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Mata-Cabrera Francisco

    2013-10-01

    Full Text Available Polyetheretherketone (PEEK composite belongs to a group of high performance thermoplastic polymers and is widely used in structural components. To improve the mechanical and tribological properties, short fibers are added as reinforcement to the material. Due to its functional properties and potential applications, it’s impor- tant to investigate the machinability of non-reinforced PEEK (PEEK, PEEK rein- forced with 30% of carbon fibers (PEEK CF30, and reinforced PEEK with 30% glass fibers (PEEK GF30 to determine the optimal conditions for the manufacture of the parts. The present study establishes the relationship between the cutting con- ditions (cutting speed and feed rate and the roughness (Ra , Rt , Rq , Rp , by develop- ing second order mathematical models. The experiments were planned as per full factorial design of experiments and an analysis of variance has been performed to check the adequacy of the models. These state the adequacy of the derived models to obtain predictions for roughness parameters within ranges of parameters that have been investigated during the experiments. The experimental results show that the most influence of the cutting parameters is the feed rate, furthermore, proved that glass fiber reinforcements produce a worse machinability.

  8. Dependence of the surface roughness of MAPLE-deposited films on the solvent parameters

    Science.gov (United States)

    Caricato, A. P.; Leggieri, G.; Martino, M.; Vantaggiato, A.; Valerini, D.; Cretì, A.; Lomascolo, M.; Manera, M. G.; Rella, R.; Anni, M.

    2010-12-01

    Matrix-assisted pulsed laser evaporation (MAPLE) was used to deposit layers of poly(9,9-dioctylfluorene) (PFO) to study the relation between the solvent properties (laser light absorption, boiling temperature and solubility parameters) and the morphology of the deposited films. To this end, the polymer was diluted (0.5 wt%) in tetrahydrofuran—THF, toluene and toluene/hexane mixtures. The thickness of the films was equal to 70±20 nm. The morphology and uniformity of the films was investigated by Atomic Force Microscopy and by the photoluminescence emission properties of the polymer films, respectively. It is shown that, although the solubility parameters of the solvents are important in controlling the film roughness and morphology, the optical absorption properties and boiling temperature play a very important role, too. In fact, for matrices characterized by the same total solubility parameter, lower roughness values are obtained for films prepared using solvents with lower penetration depth of the laser radiation and higher boiling temperatures.

  9. Do morphometric parameters and geological conditions determine chemistry of glacier surface ice? Spatial distribution of contaminants present in the surface ice of Spitsbergen glaciers (European Arctic).

    Science.gov (United States)

    Lehmann, Sara; Gajek, Grzegorz; Chmiel, Stanisław; Polkowska, Żaneta

    2016-12-01

    The chemism of the glaciers is strongly determined by long-distance transport of chemical substances and their wet and dry deposition on the glacier surface. This paper concerns spatial distribution of metals, ions, and dissolved organic carbon, as well as the differentiation of physicochemical parameters (pH, electrical conductivity) determined in ice surface samples collected from four Arctic glaciers during the summer season in 2012. The studied glaciers represent three different morphological types: ground based (Blomlibreen and Scottbreen), tidewater which evolved to ground based (Renardbreen), and typical tidewater glacier (Recherchebreen). All of the glaciers are functioning as a glacial system and hence are subject to the same physical processes (melting, freezing) and the process of ice flowing resulting from the cross-impact force of gravity and topographic conditions. According to this hypothesis, the article discusses the correlation between morphometric parameters, changes in mass balance, geological characteristics of the glaciers and the spatial distribution of analytes on the surface of ice. A strong correlation (r = 0.63) is recorded between the aspect of glaciers and values of pH and ions, whereas dissolved organic carbon (DOC) depends on the minimum elevation of glaciers (r = 0.55) and most probably also on the development of the accumulation area. The obtained results suggest that although certain morphometric parameters largely determine the spatial distribution of analytes, also the geology of the bed of glaciers strongly affects the chemism of the surface ice of glaciers in the phase of strong recession.

  10. Facilitation of tear fluid secretion by 3% diquafosol ophthalmic solution in normal human eyes.

    Science.gov (United States)

    Yokoi, Norihiko; Kato, Hiroaki; Kinoshita, Shigeru

    2014-01-01

    To evaluate the increase in tear fluid volume induced by 3% diquafosol ophthalmic solution in normal human eyes. Prospective, randomized, double-masked, comparative study. Twenty healthy adults (17 males and 3 females; mean age, 38.8 years) underwent topical instillation of 2 ophthalmic solutions, artificial tears in 1 eye and 3% diquafosol ophthalmic solution in the fellow eye, in a masked manner. The radius of curvature of the central lower tear meniscus was measured at 5, 10, 15, 30, and 60 minutes after instillation by use of reflective meniscometry, and subjects' self-evaluated symptoms of wetness and stinging using a visual analog scale. Changes after instillation in the radius of curvature from baseline (artificial tear group vs diquafosol group; mean ± standard error of the mean) were as follows: at 5 minutes, -0.008 ± 0.012 vs 0.045 ± 0.013; at 10 minutes, 0.001 ± 0.014 vs 0.057 ± 0.016; at 15 minutes, -0.012 ± 0.014 vs 0.037 ± 0.019; at 30 minutes, -0.010 ± 0.016 vs 0.030 ± 0.025; and at 60 minutes, -0.029 ± 0.012 vs -0.020 ± 0.012. The diquafosol group showed significantly greater values from 5 to 30 minutes after instillation. Of the 40 eyes, 13 showed abnormal tear film breakup time (≤5 seconds). The diquafosol group had significantly more wetness at 15 minutes after instillation than did the artificial tear group. Topical instillation of 3% diquafosol ophthalmic solution increases tear fluid on the ocular surface for up to 30 minutes in normal human eyes. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Effects of punctal occlusion on global tear proteins in patients with dry eye.

    Science.gov (United States)

    Tong, Louis; Zhou, Lei; Beuerman, Roger; Simonyi, Susan; Hollander, David A; Stern, Michael E

    2017-10-01

    To investigate effects of punctal occlusion on global tear protein levels in patients with dry eye. In this prospective, longitudinal, single-center study, nonabsorbable punctal plugs were inserted bilaterally into the lower punctum of 30 patients with moderate dry eye. Dry eye symptoms, fluorescein corneal staining, Schirmer I test, tear film break-up time, and safety were assessed in the more severely affected eye. Tear proteins at weeks 1 and 3 were quantified by iTRAQ relative to baseline preocclusion levels. Of 29 patients who completed the study, 23 (mean age 49.8 years) had sufficient tear samples for analysis. After 3 weeks, punctal occlusion significantly upregulated tear proteins, including glutathione synthase (mean of 1.6-fold, P = 0.01) and interleukin-1 receptor antagonist (1.7-fold, P = 0.032) and downregulated cholinergic receptor (neuronal) alpha-7 (0.79-fold, P = 0.039) and lymphocyte cytosolic protein-1 (0.66-fold, P = 0.012). Clustering analysis of global tear proteins revealed two clear profile changes; the first group of patients (cluster 1, n = 10) had a reduction in the inflammatory proteins (e.g., S100A8) and rise in lacrimal proteins supporting the ocular surface (e.g., lysozyme), whereas the second group (cluster 2, n = 13) had an increase in inflammatory proteins and a decrease in lacrimal proteins. Logistic regression analysis revealed that cluster 1 patients had significantly (P = 0.006) lower Schirmer scores at baseline (mean [standard deviation]: 4.3 [4.3] mm) than cluster 2 (6.8 [2.6] mm). Punctal plugs produced a beneficial pattern of tear protein change in patients with relatively low Schirmer scores within 3 weeks of punctal occlusion. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Alteration of galectin-3 in tears of patients with dry eye disease.

    Science.gov (United States)

    Uchino, Yuichi; Mauris, Jerome; Woodward, Ashley M; Dieckow, Julia; Amparo, Francisco; Dana, Reza; Mantelli, Flavio; Argüeso, Pablo

    2015-06-01

    To investigate the expression, release, and proteolytic degradation of galectin-3 in patients with dry eye disease. Observational case series with a comparison group. Tear washes and conjunctival impression cytology specimens were collected through standard procedures from 16 patients with dry eye and 11 age-matched healthy subjects. Galectin-3 content in tears was analyzed by quantitative Western blot, using recombinant galectin-3 protein to generate a calibration curve. The relative expression of galectin-3 and matrix metalloproteinase 9 (MMP9) was evaluated by quantitative polymerase chain reaction. The cleavage of galectin-3 was studied in vitro using activated recombinant MMP9 and protease inhibitors. The concentration of galectin-3 protein in tears, but not galectin-3 expression in conjunctival epithelium, was significantly higher in tears of patients with dry eye (0.38 ng/μg total protein, range 0.04-1.36) compared to healthy subjects (0.12 ng/μg total protein, range 0.00-0.41) (P tear samples from healthy subjects, whereas 50% of the dry eye samples were characterized by the additional presence of a partially degraded form (∼25.4 kDa). In our experiments, elevated expression of MMP9 in dry eye subjects correlated with the ability of active MMP9 to cleave galectin-3 from recombinant origin. Interestingly, cleavage of endogenous galectin-3 in tear samples was impaired using a broad-spectrum proteinase inhibitor cocktail, but not the pan-specific MMP inhibitor GM6001, suggesting the presence of proteases other than MMPs in promoting galectin-3 degradation in dry eye. Our results indicate that release of cellular galectin-3 into tears is associated with epithelial dysfunction in dry eye, and that galectin-3 proteolytic cleavage may contribute to impaired ocular surface barrier function. Copyright © 2015 Elsevier Inc. All rights reserved.

  13. Cohesive traction-separation relations for plate tearing under mixed mode loading

    DEFF Research Database (Denmark)

    Andersen, R. G.; Woelke, P. B.; Nielsen, K. L.

    2018-01-01

    The present study investigates a sequence of failure events related to steady-state tearing of large-scale ductile plates by employing the micro-mechanics based Gurson-Tvergaard-Needleman (GTN) model. The fracture process in front of an advancing crack is approximated by a series of 2D plane strain...... finite element models to facilitate a comprehensive study of mixed mode fracture behavior as well as a parameter study of the cohesive energy and tractions involved in the process. The results from the conducted GTN model simulations are used to define cohesive zone models suitable for plate tearing...

  14. Effect of electroerosion grinding parameters on surface quality of cylindrical pieces out of tungsten monocrystals

    International Nuclear Information System (INIS)

    Zolotykh, B.N.; Marchuk, A.I.; Nikiforov, S.V.; Serdobov, B.F.; Yakunkin, M.M.

    1978-01-01

    Experimental data are presented on the examination of the electroerosion grinding of cylindrical parts made up of tungsten single crystals. Special attention has been paid to a comparative analysis of the influence of the electroerosion cutting out and grinding on the quality characteristics of a surface. The surface quality was assessed according to a widening of the X-ray emission line (110) by means of round diffraction patterns and by the metallographic method. It is shown that the microdistortions after the electroerosion grinding are considerably greater than those resulting from the electroerosion cutting out; however, after the electroerosion grinding the number of microcracks is considerably smaller. The experimental results obtained underwent a theoretical analysis within the framework of the Mitchell-Rockswell-Hirsch dislocation theory of failure of space-centered single crystals

  15. Hyper fast radiative transfer for the physical retrieval of surface parameters from SEVIRI observations

    International Nuclear Information System (INIS)

    Liuzzi, G; Masiello, G; Serio, C; Blasi, M G; Venafra, S

    2015-01-01

    This paper describes the theoretical aspects of a fast scheme for the physical retrieval of surface temperature and emissivity from SEVIRI data, their implementation and some sample results obtained. The scheme is based on a Kalman Filter approach, which effectively exploits the temporal continuity in the observations of the geostationary Meteosat Second Generation (MSG) platform, on which SEVIRI (Spinning Enhanced Visible and InfraRed Imager) operates. Such scheme embodies in its core a physical retrieval algorithm, which employs an hyper fast radiative transfer code highly customized for this retrieval task. Radiative transfer and its customizations are described in detail. Fastness, accuracy and stability of the code are fully documented for a variety of surface features, showing a peculiar application to the massive Greek forest fires in August 2007. (paper)

  16. Spectral and parameter estimation problems arising in the metrology of high performance mirror surfaces

    International Nuclear Information System (INIS)

    Church, E.L.; Takacs, P.Z.

    1986-04-01

    The accurate characterization of mirror surfaces requires the estimation of two-dimensional distribution functions and power spectra from trend-contaminated profile measurements. The rationale behind this, and our measurement and processing procedures, are described. The distinction between profile and area spectra is indicated, and since measurements often suggest inverse-power-law forms, a discussion of classical and fractal models of processes leading to these forms is included. 9 refs

  17. Rotator cuff tears: An evidence based approach

    Science.gov (United States)

    Sambandam, Senthil Nathan; Khanna, Vishesh; Gul, Arif; Mounasamy, Varatharaj

    2015-01-01

    Lesions of the rotator cuff (RC) are a common occurrence affecting millions of people across all parts of the globe. RC tears are also rampantly prevalent with an age-dependent increase in numbers. Other associated factors include a history of trauma, limb dominance, contralateral shoulder, smoking-status, hypercholesterolemia, posture and occupational dispositions. The challenge lies in early diagnosis since a high proportion of patients are asymptomatic. Pain and decreasing shoulder power and function should alert the heedful practitioner in recognizing promptly the onset or aggravation of existing RC tears. Partial-thickness tears (PTT) can be bursal-sided or articular-sided tears. Over the course of time, PTT enlarge and propagate into full-thickness tears (FTT) and develop distinct chronic pathological changes due to muscle retraction, fatty infiltration and muscle atrophy. These lead to a reduction in tendon elasticity and viability. Eventually, the glenohumeral joint experiences a series of degenerative alterations - cuff tear arthropathy. To avert this, a vigilant clinician must utilize and corroborate clinical skill and radiological findings to identify tear progression. Modern radio-diagnostic means of ultrasonography and magnetic resonance imaging provide excellent visualization of structural details and are crucial in determining further course of action for these patients. Physical therapy along with activity modifications, anti-inflammatory and analgesic medications form the pillars of nonoperative treatment. Elderly patients with minimal functional demands can be managed conservatively and reassessed at frequent intervals. Regular monitoring helps in isolating patients who require surgical interventions. Early surgery should be considered in younger, active and symptomatic, healthy patients. In addition to being cost-effective, this helps in providing a functional shoulder with a stable cuff. An easily reproducible technique of maximal strength and

  18. Geometric Parameters of Cutting Tools that Can be Used for Forming Sided Surfaces with Variable Profile

    Directory of Open Access Journals (Sweden)

    Razumov M.

    2017-03-01

    Full Text Available This article describes machining technology of polyhedral surfaces with varying profile, which is provided by planetary motion of multiblade block tools. The features of the technology and urgency of the problem is indicated. The purpose of the study is to determine the minimum value of the clearance angle of the tool. Also, the study is carried out about changing the value of the front and rear corners during the formation of polygonal surface using a planetary gear. The scheme of calculating the impact of various factors on the value of the minimum clearance angle of the tool and kinematic front and rear corners of the instrument is provided. The mathematical formula for calculating the minimum clearance angle of the tool is given. Also, given the formula for determining the front and rear corners of the tool during driving. This study can be used in the calculation of the design operations forming multifaceted external surfaces with a variable profile by using the planetary gear.

  19. Differential protein expression in tears of patients with primary open angle and pseudoexfoliative glaucoma.

    Science.gov (United States)

    Pieragostino, Damiana; Bucci, Sonia; Agnifili, Luca; Fasanella, Vincenzo; D'Aguanno, Simona; Mastropasqua, Alessandra; Ciancaglini, Marco; Mastropasqua, Leonardo; Di Ilio, Carmine; Sacchetta, Paolo; Urbani, Andrea; Del Boccio, Piero

    2012-04-01

    Primary open angle (POAG) and pseudoexfoliative glaucoma (PXG) are the most common primary and secondary forms of glaucoma, respectively. Even though the patho-physiology, aqueous humor composition, risk factors, clinical features, therapy and drug induced ocular surface changes in POAG and PXG have been widely studied, to date information concerning tear protein characterization is lacking. Tears are a source of nourishment for ocular surface tissues and a vehicle to remove local waste products, metabolized drugs and inflammatory mediators produced in several ophthalmic diseases. In glaucoma, the proteomic definition of tears may provide insights concerning patho-physiology of the disease and ocular surface modifications induced by topical therapy. Our study aimed at characterizing protein patterns in tears of patients with medically controlled POAG and PXG. A comparative tears proteomic analysis by label-free LC-MS(E) highlighted differences in the expression of several proteins in the two glaucoma sub-types and control subjects, highlighting inflammation pathways expressed in both diseases. Results were independently reconfirmed by SDS-PAGE and linear MALDI-TOF MS, validating altered levels of Lysozyme C, Lipocalin-1, Protein S100, Immunoglobulins and Prolactin Inducible Protein. Moreover, we found a differential pattern of phosphorylated Cystatin-S that distinguishes the two pathologies. The most relevant results suggest that in both pathologies there may be active inflammation pathways related to the disease and/or induced by therapy. We show, for the first time, tear protein patterns expressed under controlled intraocular pressure conditions in POAG and PXG subjects. These findings could help in the understanding of molecular machinery underlying these ophthalmologic diseases, resulting in early diagnosis and more specific therapy.

  20. A case of recurrent bloody tears

    Directory of Open Access Journals (Sweden)

    Karslıoğlu Ş

    2011-07-01

    Full Text Available Şafak Karslioğlu1, Ilke Bahçeci Şimşek2, Müslime Akbaba11Ìstanbul Oculoplastic and Orbital Surgery and Ocular Oncology Center, 2Ophthalmology Department, Medicine Hospital, Ìstanbul, TurkeyAbstract: Well-known causes of blood-tinged epiphora are conjunctival lesions, tumors of the lacrimal apparatus, and systemic bleeding disorders. We describe an unusual patient who presented with recurrent episodes of bloody tearing which began following an erythema multiforme-like drug eruption. He experienced chronic conjunctivitis which resulted in a few minor symblephara. One year later, the patient developed attacks of bloody tearing. All clinical, radiologic, and laboratory investigations related to bloody epiphora were within normal limits except for a mild, nonspecific chronic inflammatory reaction in the perivascular tissues of the lacrimal gland and orbital soft tissues. Also, an increase in vascular permeability and contrast extravasation on carotid angiography was detected. High-dose vitamin C was administered. The patient continued to have unilateral bloody tears intermittently for two years, but the episodes became much less frequent and had resolved by three years. It is conceivable that increased vascular permeability following the systemic inflammatory process could have played a role in the etiology of recurrent bloody tears in this atypical patient.Keywords: bloody tears, erythema multiforme, drug eruption, vitamin C

  1. Anamnestic prediction of bucket handle compared to other tear patterns of the medial meniscus in stable knees.

    Science.gov (United States)

    Haviv, Barak; Bronak, Shlomo; Kosashvili, Yona; Thein, Rafael

    2016-12-01

    The aim of this study was to analyze and compare the preoperative anamnestic details between patients with an arthroscopic diagnosis of bucket handle and other tear patterns of the medial meniscus in stable knees. A total of 204 patients (mean age 49.3 ± 13 years) were included in the study. The mean age was 49.3 ± 13 years. The study group included 65 patients (63 males, 2 females) with an arthroscopic diagnosis of bucket handle tear and the control group included 139 patients (90 males, 49 females) with non-bucket handle tear patterns. The preoperative clinical assessments of the two groups were analyzed retrospectively. Anamnestic prediction for the diagnosis of a bucket handle tear was based upon various medical history parameters. Multivariate logistic regression was carried out to identify independent anamnestic factors for predicting isolated bucket handle tears of the medial meniscus compared to non-bucket handle tears. Analysis of the multivariate logistic regression yielded 3 statistically significant independent anamnestic risk factors for predicting isolated bucket handle tears of the medial meniscus: male gender (OR, 9.7; 95% CI, 1.1-37.6), locking events (OR, 4.6; 95% CI, 1.8-11.3) and pain in extension (OR, 6.9; 95% CI, 2.5-23.7). Other preoperative variables such as age, BMI, activity level, comorbidities, duration of symptoms, pain location, preceding injury and its mechanism had no significant effect on tear pattern. Preoperative strong clues for bucket handle tears of the medial meniscus in stable knees are male gender, locking events and limitation in extension. Level III, Diagnostic study. Copyright © 2016 Turkish Association of Orthopaedics and Traumatology. Production and hosting by Elsevier B.V. All rights reserved.

  2. Associations between motor unit action potential parameters and surface EMG features.

    Science.gov (United States)

    Del Vecchio, Alessandro; Negro, Francesco; Felici, Francesco; Farina, Dario

    2017-10-01

    The surface interference EMG signal provides some information on the neural drive to muscles. However, the association between neural drive to muscle and muscle activation has long been debated with controversial indications due to the unavailability of motor unit population data. In this study, we clarify the potential and limitations of interference EMG analysis to infer motor unit recruitment strategies with an experimental investigation of several concurrently active motor units and of the associated features of the surface EMG. For this purpose, we recorded high-density surface EMG signals during linearly increasing force contractions of the tibialis anterior muscle, up to 70% of maximal force. The recruitment threshold (RT), conduction velocity (MUCV), median frequency (MDF MU ), and amplitude (RMS MU ) of action potentials of 587 motor units from 13 individuals were assessed and associated with features of the interference EMG. MUCV was positively associated with RT ( R 2 = 0.64 ± 0.14), whereas MDF MU and RMS MU showed a weaker relation with RT ( R 2 = 0.11 ± 0.11 and 0.39 ± 0.24, respectively). Moreover, the changes in average conduction velocity estimated from the interference EMG predicted well the changes in MUCV ( R 2 = 0.71), with a strong association to ankle dorsiflexion force ( R 2 = 0.81 ± 0.12). Conversely, both the average EMG MDF and RMS were poorly associated with motor unit recruitment. These results clarify the limitations of EMG spectral and amplitude analysis in inferring the neural strategies of muscle control and indicate that, conversely, the average conduction velocity could provide relevant information on these strategies. NEW & NOTEWORTHY The surface EMG provides information on the neural drive to muscles. However, the associations between EMG features and neural drive have been long debated due to unavailability of motor unit population data. Here, by using novel highly accurate decomposition of the EMG, we related motor unit

  3. New techniques for improved performance in surface blasting operation and optimisation of blast design parameters

    Energy Technology Data Exchange (ETDEWEB)

    Roy, P.P. [Central Mining Research Institute, Dhanbad (India). Blasting Dept.

    1999-02-01

    Experimental blasts were conducted for optimisation of blasting parameters using separate technologies involving non-electric initiation systems, air decking accessories in conjunction with different explosive products like emulsion (cartridge and site-mixed), slurries (cartridge and site-mixed) and ANFO. The cost associated with each such technology was then compared with the conventional methods of drilling and blasting operations. The results of cost analyses are given. Theoretical and practical aspects of such technologies and their best possible usage in order to establish the desired fragmentation, muck profile, wall control and ultimately the accepted level of costs are mentioned in subsequent sections. 16 refs., 17 figs., 8 plates, 11 tabs.

  4. Effect of field of view on MR diagnosis of rotator cuff tears

    International Nuclear Information System (INIS)

    Tuite, M.J.; Yandow, D.R.; De Smet, A.A.; Orwin, J.F.; Quintana, F.A.

    1995-01-01

    One hundred shoulder MR scans with surgical correlation were evaluated for the presence or absence of a cuff tear. The sensitivity and specificity of MR relative to the surgical results were determined for the 59 patients scanned with a 24-cm FOV, and the 41 patients scanned with an 18-cm FOV. All other imaging parameters including acquisition time were identical. The sensitivity and specificity of the two groups were compared using a t-test. The specificity of MR for diagnosing a rotator cuff tear improved from 0.65 for the 24-cm FOV group to 0.89 for the 18-cm FOV group (P = 0.04). The sensitivity changed from 0.91 to 0.96 (P = 0.25). Reducing the FOV from 24 cm to 18 cm results in a statistically significant improvement in specificity of MR for diagnosing rotator cuff tears. (orig./MG)

  5. Effect of field of view on MR diagnosis of rotator cuff tears

    Energy Technology Data Exchange (ETDEWEB)

    Tuite, M J [Dept. of Radiology, Univ. of Wisconsin Clinical Science Center, Madison, WI (United States); Yandow, D R [Dept. of Radiology, Univ. of Wisconsin Clinical Science Center, Madison, WI (United States); De Smet, A A [Dept. of Radiology, Univ. of Wisconsin Clinical Science Center, Madison, WI (United States); Orwin, J F [Div. of Orthopedic Surgery, Univ. of Wisconsin Clinical Science Center, Madison, WI (United States); Quintana, F A [Dept. of Biostatistics, Univ. of Wisconsin Clinical Science Center, Madison, WI (United States)

    1995-10-01

    One hundred shoulder MR scans with surgical correlation were evaluated for the presence or absence of a cuff tear. The sensitivity and specificity of MR relative to the surgical results were determined for the 59 patients scanned with a 24-cm FOV, and the 41 patients scanned with an 18-cm FOV. All other imaging parameters including acquisition time were identical. The sensitivity and specificity of the two groups were compared using a t-test. The specificity of MR for diagnosing a rotator cuff tear improved from 0.65 for the 24-cm FOV group to 0.89 for the 18-cm FOV group (P = 0.04). The sensitivity changed from 0.91 to 0.96 (P = 0.25). Reducing the FOV from 24 cm to 18 cm results in a statistically significant improvement in specificity of MR for diagnosing rotator cuff tears. (orig./MG)

  6. Analysis of Factors Associated With the Tear Film Lipid Layer Thickness in Normal Eyes and Patients With Dry Eye Syndrome.

    Science.gov (United States)

    Jung, Ji Won; Park, Si Yoon; Kim, Jin Sun; Kim, Eung Kweon; Seo, Kyoung Yul; Kim, Tae-Im

    2016-08-01

    To determine the effects of clinical variables, including age, sex, history of refractive or cataract surgery, contact lens use, and ocular surface and meibomian gland parameters on the lipid layer thickness (LLT) in normal subjects and patients with dry eye syndrome (DES). A total of 64 normal subjects and 326 patients with DES were enrolled, and they underwent measurements of LLT with a LipiView interferometer and tear meniscus height using optical coherence tomography, tear film break-up time (TBUT) determination, ocular surface staining, Schirmer's test, examination of the lid margins and meibomian glands, and assessment using the Ocular Surface Disease Index (OSDI). In normal subjects, the median (range) LLT was 67 (33-100) nm, and age was the only factor that was significantly associated with LLT (β = 0.678, P = 0.028). In patients with DES, the median (range) LLT was 84 (20-100) nm, and 79.0% of the participants fulfilled the diagnostic criteria for meibomian gland dysfunction (MGD). In a multivariate analysis, increased age and female sex were significantly related to increased LLT (β = 0.282, P = 0.005 and β = 11.493, P < 0.001), and hypersecretory MGD and lid margin inflammation were independently associated with increased LLT (β = 11.299, P = 0.001 and β = 12.747, P = 0.001). Lipid layer thickness measurements using a new interferometer are significantly affected by demographic factors such as age, sex, ocular surgical history, and MGD type. Therefore, all of these factors must be considered in the diagnosis of ocular surface diseases.

  7. Dysfunctional tear syndrome: dry eye disease and associated tear film disorders – new strategies for diagnosis and treatment

    Science.gov (United States)

    Milner, Mark S.; Beckman, Kenneth A.; Luchs, Jodi I.; Allen, Quentin B.; Awdeh, Richard M.; Berdahl, John; Boland, Thomas S.; Buznego, Carlos; Gira, Joseph P.; Goldberg, Damien F.; Goldman, David; Goyal, Raj K.; Jackson, Mitchell A.; Katz, James; Kim, Terry; Majmudar, Parag A.; Malhotra, Ranjan P.; McDonald, Marguerite B.; Rajpal, Rajesh K.; Raviv, Tal; Rowen, Sheri; Shamie, Neda; Solomon, Jonathan D.; Stonecipher, Karl; Tauber, Shachar; Trattler, William; Walter, Keith A.; Waring, George O.; Weinstock, Robert J.; Wiley, William F.; Yeu, Elizabeth

    2017-01-01

    Dysfunctional tear syndrome (DTS) is a common and complex condition affecting the ocular surface. The health and normal functioning of the ocular surface is dependent on a stable and sufficient tear film. Clinician awareness of conditions affecting the ocular surface has increased in recent years because of expanded research and the publication of diagnosis and treatment guidelines pertaining to disorders resulting in DTS, including the Delphi panel treatment recommendations for DTS (2006), the International Dry Eye Workshop (DEWS) (2007), the Meibomian Gland Dysfunction (MGD) Workshop (2011), and the updated Preferred Practice Pattern guidelines from the American Academy of Ophthalmology pertaining to dry eye and blepharitis (2013). Since the publication of the existing guidelines, new diagnostic techniques and treatment options that provide an opportunity for better management of patients have become available. Clinicians are now able to access a wealth of information that can help them obtain a differential diagnosis and treatment approach for patients presenting with DTS. This review provides a practical and directed approach to the diagnosis and treatment of patients with DTS, emphasizing treatment that is tailored to the specific disease subtype as well as the severity of the condition. PMID:28099212

  8. Dysfunctional tear syndrome: dry eye disease and associated tear film disorders - new strategies for diagnosis and treatment.

    Science.gov (United States)

    Milner, Mark S; Beckman, Kenneth A; Luchs, Jodi I; Allen, Quentin B; Awdeh, Richard M; Berdahl, John; Boland, Thomas S; Buznego, Carlos; Gira, Joseph P; Goldberg, Damien F; Goldman, David; Goyal, Raj K; Jackson, Mitchell A; Katz, James; Kim, Terry; Majmudar, Parag A; Malhotra, Ranjan P; McDonald, Marguerite B; Rajpal, Rajesh K; Raviv, Tal; Rowen, Sheri; Shamie, Neda; Solomon, Jonathan D; Stonecipher, Karl; Tauber, Shachar; Trattler, William; Walter, Keith A; Waring, George O; Weinstock, Robert J; Wiley, William F; Yeu, Elizabeth

    2017-01-01

    Dysfunctional tear syndrome (DTS) is a common and complex condition affecting the ocular surface. The health and normal functioning of the ocular surface is dependent on a stable and sufficient tear film. Clinician awareness of conditions affecting the ocular surface has increased in recent years because of expanded research and the publication of diagnosis and treatment guidelines pertaining to disorders resulting in DTS, including the Delphi panel treatment recommendations for DTS (2006), the International Dry Eye Workshop (DEWS) (2007), the Meibomian Gland Dysfunction (MGD) Workshop (2011), and the updated Preferred Practice Pattern guidelines from the American Academy of Ophthalmology pertaining to dry eye and blepharitis (2013). Since the publication of the existing guidelines, new diagnostic techniques and treatment options that provide an opportunity for better management of patients have become available. Clinicians are now able to access a wealth of information that can help them obtain a differential diagnosis and treatment approach for patients presenting with DTS. This review provides a practical and directed approach to the diagnosis and treatment of patients with DTS, emphasizing treatment that is tailored to the specific disease subtype as well as the severity of the condition.

  9. Influence of process parameters on plasma electrolytic surface treatment of tantalum for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Maciej, E-mail: maciej.sowa@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Woszczak, Maja; Kazek-Kęsik, Alicja [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland); Dercz, Grzegorz [Institute of Materials Science, University of Silesia, 75 Pułku Piechoty Street 1A, 41-500 Chorzów (Poland); Korotin, Danila M. [M.N. Mikheev Institute of Metal Physics of the Ural Branch of Russian Academy of Sciences, S. Kovalevskoi Street 18, 620990 Yekaterinburg (Russian Federation); Institute of Physics and Technology, Ural Federal University, Mira Street 19, 620002 Yekaterinburg (Russian Federation); Zhidkov, Ivan S. [Institute of Physics and Technology, Ural Federal University, Mira Street 19, 620002 Yekaterinburg (Russian Federation); Kurmaev, Ernst Z. [M.N. Mikheev Institute of Metal Physics of the Ural Branch of Russian Academy of Sciences, S. Kovalevskoi Street 18, 620990 Yekaterinburg (Russian Federation); Institute of Physics and Technology, Ural Federal University, Mira Street 19, 620002 Yekaterinburg (Russian Federation); Cholakh, Seif O. [Institute of Physics and Technology, Ural Federal University, Mira Street 19, 620002 Yekaterinburg (Russian Federation); Basiaga, Marcin [Faculty of Biomedical Engineering, Silesian University of Technology, Gen. de Gaulle’a Street 66, 41-800 Zabrze (Poland); Simka, Wojciech, E-mail: wojciech.simka@polsl.pl [Faculty of Chemistry, Silesian University of Technology, B. Krzywoustego Street 6, 44-100 Gliwice (Poland)

    2017-06-15

    Highlights: • 2-step plasma electrolytic oxidation (PEO) of tantalum was investigated. • PEO coatings surface composition were reflected by the composition of anodizing baths. • Hydrophobic surfaces were obtained from acetate and formate containing baths. • Bioactive phases were identified. - Abstract: This work aims to quantify the effect of anodization voltage and electrolyte composition used during DC plasma electrolytic oxidation (PEO), operated as a 2-step process, on the surface properties of the resulting oxide coatings on tantalum. The first step consisted of galvanostatic anodization (150 mA cm{sup −2}) of the tantalum workpiece up to several limiting voltages (200, 300, 400 and 500 V). After attaining the limiting voltage, the process was switched to voltage control, which resulted in a gradual decrease of the anodic current density. The anodic treatment was realized in a 0.5 M Ca(H{sub 2}PO{sub 2}){sub 2} solution, which was then modified by the addition of 1.15 M Ca(HCOO){sub 2} as well as 1.15 M and 1.5 M Mg(CH{sub 3}COO){sub 2}. The increasing voltage of anodization led to the formation of thicker coatings, with larger pores and enriched with electrolytes species to a higher extent. The solutions containing HCOO{sup −} and CH{sub 3}COO{sup −} ions caused the formation of coatings which were slightly hydrophobic (high contact angle). In the case of the samples anodized up to 500 V, scattered crystalline deposits were observed. Bioactive phases, such as hydroxyapatite, were detected in the treated oxide coatings by XRD and XPS.

  10. The influence of non-polar lipids on tear film dynamics

    KAUST Repository

    Bruna, M.; Breward, C.  J.  W.

    2014-01-01

    © 2014 Cambridge University Press. In this paper we examine the effect that physiological non-polar lipids, residing on the surface of an aqueous tear film, have on the film evolution. In our model we track the evolution of the thickness of the non

  11. Organization of lipids in the tear film: a molecular-level view.

    Directory of Open Access Journals (Sweden)

    Alicja Wizert

    Full Text Available Biophysical properties of the tear film lipid layer are studied at the molecular level employing coarse grain molecular dynamics (MD simulations with a realistic model of the human tear film. In this model, polar lipids are chosen to reflect the current knowledge on the lipidome of the tear film whereas typical Meibomian-origin lipids are included in the thick non-polar lipids subphase. Simulation conditions mimic those experienced by the real human tear film during blinks. Namely, thermodynamic equilibrium simulations at different lateral compressions are performed to model varying surface pressure, and the dynamics of the system during a blink is studied by non-equilibrium MD simulations. Polar lipids separate their non-polar counterparts from water by forming a monomolecular layer whereas the non-polar molecules establish a thick outermost lipid layer. Under lateral compression, the polar layer undulates and a sorting of polar lipids occurs. Moreover, formation of three-dimensional aggregates of polar lipids in both non-polar and water subphases is observed. We suggest that these three-dimensional structures are abundant under dynamic conditions caused by the action of eye lids and that they act as reservoirs of polar lipids, thus increasing stability of the tear film.

  12. Peeling back the lithosphere: Controlling parameters, surface expressions and the future directions in delamination modeling

    Science.gov (United States)

    Göğüş, Oğuz H.; Ueda, Kosuke

    2018-06-01

    Geodynamical models investigate the rheological and physical properties of the lithosphere that peels back (delaminates) from the upper-middle crust. Meanwhile, model predictions are used to relate to a set of observations in the geological context to the test the validity of delamination. Here, we review numerical and analogue models of delamination from these perspectives and provide a number of first-order topics which future modeling studies may address. Models suggest that the presence of the weak lower crust that resides between the strong mantle lithosphere (at least 100 times more viscous/stronger) and the strong upper crust is necessary to develop delamination. Lower crustal weakening may be induced by melt infiltration, shear heating or it naturally occurs through the jelly sandwich type strength profile of the continental lithosphere. The negative buoyancy of the lithosphere required to facilitate the delamination is induced by the pre-existing ocean subduction and/or the lower crustal eclogitization. Surface expression of the peeling back lithosphere has a distinct transient and migratory imprint on the crust, resulting in rapid surface uplift/subsidence, magmatism, heating and shortening/extension. New generation of geodynamical experiments can explain how different types of melting (e.g hydrated, dry melting) occurs with delamination. Reformation of the lithosphere after removal, three dimensional aspects, and the termination of the process are key investigation areas for future research. The robust model predictions, as with other geodynamic modeling studies should be reconciled with observations.

  13. Quantifying the Contributions of Environmental Parameters to Ceres Surface Net Radiation Error in China

    Science.gov (United States)

    Pan, X.; Yang, Y.; Liu, Y.; Fan, X.; Shan, L.; Zhang, X.

    2018-04-01

    Error source analyses are critical for the satellite-retrieved surface net radiation (Rn) products. In this study, we evaluate the Rn error sources in the Clouds and the Earth's Radiant Energy System (CERES) project at 43 sites from July in 2007 to December in 2007 in China. The results show that cloud fraction (CF), land surface temperature (LST), atmospheric temperature (AT) and algorithm error dominate the Rn error, with error contributions of -20, 15, 10 and 10 W/m2 (net shortwave (NSW)/longwave (NLW) radiation), respectively. For NSW, the dominant error source is algorithm error (more than 10 W/m2), particularly in spring and summer with abundant cloud. For NLW, due to the high sensitivity of algorithm and large LST/CF error, LST and CF are the largest error sources, especially in northern China. The AT influences the NLW error large in southern China because of the large AT error in there. The total precipitable water has weak influence on Rn error even with the high sensitivity of algorithm. In order to improve Rn quality, CF and LST (AT) error in northern (southern) China should be decreased.

  14. Plate Tearing Under Mixed Mode Loading

    DEFF Research Database (Denmark)

    Andersen, Rasmus Grau; Nielsen, Kim Lau; Felter, Christian Lotz

    2016-01-01

    the mesh cannot accurately capture the localization process that precedes ductile failure. To fertilize accurate predictions of such sheet tearing, the energy dissipated during localization must, therefore, be accounted for in the cohesive traction-separation law. The fact is that the local thinning...... that takes place in front of an advancing crack can significantly enhance the crack growth resistanceas the energy going into thinning the sheet typically dominates the total fracture energy.This has been investigated in great details for the case of pure Mode I tearing and both the energy dissipation, peak...... stress, and shape of the cohesive traction-separation law have been laid out. In a similar fashion, the present study resolves the sequence of failure details related to steady-state sheet tearing under mixed mode loading by employing the micro-mechanics based Gurson model. But, the fracture process...

  15. Slab tears and intermediate-depth seismicity

    Science.gov (United States)

    Meighan, Hallie E.; ten Brink, Uri S.; Pulliam, Jay

    2013-01-01

    Active tectonic regions where plate boundaries transition from subduction to strike slip can take several forms, such as triple junctions, acute, and obtuse corners. Well-documented slab tears that are associated with high rates of intermediate-depth seismicity are considered here: Gibraltar arc, the southern and northern ends of the Lesser Antilles arc, and the northern end of Tonga trench. Seismicity at each of these locations occurs, at times, in the form of swarms or clusters, and various authors have proposed that each marks an active locus of tear propagation. The swarms and clusters start at the top of the slab below the asthenospheric wedge and extend 30–60 km vertically downward within the slab. We propose that these swarms and clusters are generated by fluid-related embrittlement of mantle rocks. Focal mechanisms of these swarms generally fit the shear motion that is thought to be associated with the tearing process.

  16. Bilateral Giant Retinal Tear and Sequential Vitrectomy.

    Science.gov (United States)

    Mustapha, Mushawiahti; Roufail Franzco, Edward

    2017-01-01

    To describe the excellent outcome of surgery for bilateral giant retinal tears (GRTs) with better options of endotamponade. This is a case report of a 62-year-old man who presented with bilateral GRTs and associated retinal detachment. The tear in the right eye was supero-temporal and silicone oil was used as an endotamponade. The tear in the left eye was infero-temporal and perfluorocarbon liquid was used as an endotamponade. The outcome at 6 months after surgery was excellent with visual acuities of 6/6 in both eyes. Improved availability of endotamponade agents allows repair of bilateral GRTs to be done at the same time, with good surgical outcomes.

  17. Rotator cuff tear measurement by arthropneumotomography

    International Nuclear Information System (INIS)

    Kilcoyne, R.F.; Matsen, F.A. III

    1983-01-01

    Five years of experience with a method of shoulder arthrography using upright tomography in cases of suspected or known rotator cuff tears has demonstrated its effectiveness. The value of the procedure lies in its ability to demonstrate the size of the cuff tear and the thickness of the remaining cuff tissue. This information provides the surgeon with a preoperative estimate of the difficulty of the repair and the prognosis for a good functional recovery. In 33 cases, there was good correlation between the upright thin-section tomogram findings and the surgical results. The tomograms provided better information about the size of the tear and the quality of the remaining cuff than did plain arthrograms

  18. Effects of wearing a daily disposable lens on tear film: a randomised controlled trial.

    Science.gov (United States)

    Chong, Pamela Qin Yi; Yeo, Sharon; Too, Cheah Loon; Boo, Cynthia; Tong, Louis

    2016-05-01

    Contact lens-induced dry eye is commonly encountered, although its extent is not well documented with daily disposable lenses. A novel type of contact lens system incorporating moisturising agent (alginic acid) has been developed. The aim of this study was to evaluate the effect of wearing daily 2-hydroxyethyl methacrylate disposable contact lenses for seven days on tear stability, conjunctival and limbal redness and dry eye symptoms. Then, we aimed to determine whether lens solutions containing alginic acid had any influence on tear parameters. This was a seven-day parallel group double-masked clinical trial of previous contact lens wearers, where participants were randomly assigned to wearing SEED 1dayPure moisture contact lenses with (n = 15) or without alginic acid (n = 15). Tear lipid layer thickness (LLT), non-invasive tear break-up time (NIBUT), conjunctival redness, corneal fluorescein staining, tear break-up time and Schirmer I readings were measured. Symptom severity and frequency were evaluated and combined using a global score from visual analogue scales. The mean age and standard deviation of the participants was 25 ± 3.8 years. There were 24 females and six males. After reintroduction of contact lens wear for one week, there was significant improvement in the global symptom score; however, this may not be clinically significant. There were small and clinically insignificant changes in limbal and conjunctival hyperaemia but no significant changes in lipid layer thickness, Schirmer I and NIBUT in overall participants. The use of alginic acid in lens solutions did not affect these parameters compared to control lenses (p > 0.05). After seven days of wearing a modern daily disposable lens, there was no significant deterioration of tear function in a group of young contact lens wearers. In this short-term study, there was no evidence of significant benefit of lens solutions containing alginic acid used with HEMA lenses. © 2016 The Authors Clinical and

  19. Growth of the double Tearing mode in a plasma cylinder

    International Nuclear Information System (INIS)

    Gatilov, V.V.; Sagalakov, A.M.; Ul'chenko, V.F.

    1989-01-01

    Within the framework of the linear theory the growth of Tearing modes in collisional plasma of a cylindrical filament with a free boundary in the presence of two resonance surfaces is studied. The boundary problems for the system of Kadomtsev-Pogutse equation were solved numerically using the method of differential run which was widely used to study the stability of viscous liquid flows. The asymptotic dependences for the increments are determined. The regular behaviour of increments in the case of drawing together of resonance surfaces is fiound. A very strong destabilizing factor of conductivity inhomogeneity on modes 1/1, 2/1 connected with the resonance surface in the near-the-boundary plasma region is found

  20. Aero-thermal optimization of film cooling flow parameters on the suction surface of a high pressure turbine blade

    Science.gov (United States)

    El Ayoubi, Carole; Hassan, Ibrahim; Ghaly, Wahid

    2012-11-01

    This paper aims to optimize film coolant flow parameters on the suction surface of a high-pressure gas turbine blade in order to obtain an optimum compromise between a superior cooling performance and a minimum aerodynamic penalty. An optimization algorithm coupled with three-dimensional Reynolds-averaged Navier Stokes analysis is used to determine the optimum film cooling configuration. The VKI blade with two staggered rows of axially oriented, conically flared, film cooling holes on its suction surface is considered. Two design variables are selected; the coolant to mainstream temperature ratio and total pressure ratio. The optimization objective consists of maximizing the spatially averaged film cooling effectiveness and minimizing the aerodynamic penalty produced by film cooling. The effect of varying the coolant flow parameters on the film cooling effectiveness and the aerodynamic loss is analyzed using an optimization method and three dimensional steady CFD simulations. The optimization process consists of a genetic algorithm and a response surface approximation of the artificial neural network type to provide low-fidelity predictions of the objective function. The CFD simulations are performed using the commercial software CFX. The numerical predictions of the aero-thermal performance is validated against a well-established experimental database.

  1. The effect of Meibomian lipids and tear proteins on evaporation rate under controlled in vitro conditions.

    Science.gov (United States)

    Herok, George Henryk; Mudgil, Poonam; Millar, Thomas James

    2009-07-01

    The lipid layer of the tear film is associated with preventing evaporative loss. The ability of human Meibomian lipids to reduce evaporation in vitro was tested. Films of human or animal Meibomian lipids or mixtures of cholesterol and phosphatidylcholine were spread on the surface of either artificial buffer or on whole tears and placed on a mass balance that was enclosed in a sealed chamber. The temperature was adjusted to 37 degrees C and gas flow was controlled. Increasing the amounts of Meibomian lipids gave a very small reduction in evaporation. It was concluded from these in vitro experiments that prevention of evaporation from the tear film is not due to the Meibomian lipids alone, but is more likely to be due to a complex interaction between components of the aqueous and the Meibomian lipids.

  2. Analysis of the correlation between tear film changes of allergic conjunctivitis and dry eye

    Directory of Open Access Journals (Sweden)

    Yong Li

    2014-07-01

    Full Text Available AIM: To analyze the correlation between tear film changes of allergic conjunctivitis and dry eye, then provide clinical references for better treatment. METHODS: Fifty patients with allergic conjunctivitis were taken as the observation group, the control group was selected based on 1:1 case control theory, and we chose 50 health volunteers without ocular surface diseases, xerophthalmia and systematic diseases randomly, then fluorescein(FLstaining, break-up time(BUT, Schirner I test(SⅠt, tear meniscus high(TMHand slit-lamp examinations were performed in the two groups. RESULTS: In the observation group, FL, BUT, SIt, TMH of right eyes and left eyes were statistically significant correlated(PPPCONCLUSION: Due to inflammatory mediators participation, allergic conjunctivitis could lead to the stability changes of tear film which cause in dry eye. The stability changes of allergic conjunctivitis correlate to the damage degree of epithelium.

  3. Lessons from the biophysics of interfaces: Lung surfactant and tear fluid

    DEFF Research Database (Denmark)

    Rantamaki, A.; Telenius, J.; Koivuniemi, A.

    2011-01-01

    The purpose of this review is to provide insight into the biophysical properties and functions of tear fluid and lung surfactant - two similar fluids covering the epithelium of two distinctive organs. Both fluids form a layer-like structure that essentially comprise of an aqueous layer next......-active function of the fluid film. The lipid layer of lung surfactant comprises mainly of phospholipids, especially phosphatidylcholines, and only small amounts of non-polar lipids, mainly cholesterol. In contrast, tear fluid lipid layer comprises of a mixture of polar and non-polar lipids. Howeve