Academic literature on the topic 'Crest distance'
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Journal articles on the topic "Crest distance"
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Easa, Said M., Yasser Hassan, and A. O. Abd El Halim. "Sight distance evaluation on complex highway vertical alignments." Canadian Journal of Civil Engineering 23, no. 3 (June 1, 1996): 577–86. http://dx.doi.org/10.1139/l96-866.
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Sight distance (stopping, passing, and decision) is a key element in highway geometric design. Existing models for evaluating sight distance on vertical alignments are applicable only to simple, isolated elements such as a crest vertical curve, a sag vertical curve, and a reverse vertical curve (a sag curve following a crest curve, or vice versa). This paper presents an analytical methodology for evaluating sight distance on complex vertical alignments that involve any combination of vertical alignment elements. The methodology can be used for evaluating passing sight distance on two-lane highways, and stopping sight distance and decision sight distance on all highways. Sight distance controlled by the headlight beam can also be evaluated. The locations of sight-hidden dips, which may develop when a sag vertical curve follows a crest vertical curve with or without a common tangent, can be determined. Also, sight distances obstructed by overpasses are evaluated. A profile of the available sight distance can be established and used to evaluate sight distance deficiency and the effect of alignment improvements. A software was developed and can be used for determining the available sight distance accurately. The software may replace the current field and graphical practice for establishing the no-passing zones and evaluating stopping and decision sight distances on complex vertical alignments. Key words: sight distance, vertical alignment, highway, passing zones.
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Mehdizadeh, Mojdeh, Negar Maarefat, and Shervin Bagherieh. "Comparison of Accuracy of determining the Distance between Alveolar Crest and Cementoenamel Junction in Digital Radiography with Scanora and DentalEye Software Programs." Journal of Contemporary Dental Practice 17, no. 10 (2016): 815–19. http://dx.doi.org/10.5005/jp-journals-10024-1936.
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ABSTRACT Aim To compare the accuracy of determining the distance between alveolar crest and cementoenamel junction (CEJ) in digital radiography with two image processing software programs. Materials and methods In this in vitro study, 63 sites in a dried human mandible underwent digital periapical radiography. The distance from the alveolar crest to the CEJ was calculated using DentalEye and Scanora software programs and compared with the standard mode (measured on the skull). Statistical analysis was performed with analysis of variance (ANOVA) and paired t-test using Statistical Package for the Social Sciences (SPSS) 23 at α = 0.05. Results There were significant differences in the distances between CEJ and the alveolar crest at the mesial surfaces as measured by the three techniques in standard mode, using DentalEye and Scanora (p-value ≤0.03) softwares; however, there were no significant differences between the results on distal surfaces (p-value = 0.248). Conclusion Under the limitations of the present study, the measurements made to determine the distance from the CEJ to the alveolar crest with DentalEye and Scanora, relative to each other, and relative to the standard mode, were accurate only on distal surfaces of teeth. Clinical significance Digital dental software programs are useful assets that can enhance the diagnosing ability and reduce the need of taking extra images. How to cite this article Mehdizadeh M, Maarefat N, Bagherieh S. Comparison of Accuracy of determining the Distance between Alveolar Crest and Cementoenamel Junction in Digital Radiography with Scanora and DentalEye Software Programs. J Contemp Dent Pract 2016;17(10):815-819.
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Sarkar, Sankar, Sk Zeeshan Ali, and Subhasish Dey. "Turbulence in Wall-Wake Flow Downstream of an Isolated Dunal Bedform." Water 11, no. 10 (September 22, 2019): 1975. http://dx.doi.org/10.3390/w11101975.
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This study examines the turbulence in wall-wake flow downstream of an isolated dunal bedform. The streamwise flow velocity and Reynolds shear stress profiles at the upstream and various streamwise distances downstream of the dune were obtained. The results reveal that in the wall-wake flow, the third-order moments change their signs below the dune crest, whereas their signs remain unaltered above the crest. The near-wake flow is featured by sweep events, whereas the far-wake flow is controlled by the ejection events. Downstream of the dune, the turbulent kinetic energy production and dissipation rates, in the near-bed flow zone, are positive. However, they reduce as the vertical distance increases up to the lower-half of the dune height and beyond that, they increase with an increase in vertical distance, attaining their peaks at the crest. The turbulent kinetic energy diffusion and pressure energy diffusion rates, in the near-bed flow zone, are negative, whereas they attain their positive peaks at the crest. The anisotropy invariant maps indicate that the data plots in the wall-wake flow form a looping trend. Below the crest, the turbulence has an affinity to a two-dimensional isotropy, whereas above the crest, the anisotropy tends to reduce to a quasi-three-dimensional isotropy.
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Dey, Subhasish, Prianka Paul, Sk Zeeshan Ali, and Ellora Padhi. "Reynolds stress anisotropy in flow over two-dimensional rigid dunes." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 476, no. 2242 (October 2020): 20200638. http://dx.doi.org/10.1098/rspa.2020.0638.
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Characteristics of turbulence anisotropy in flow over two-dimensional rigid dunes are analysed. The Reynolds stress anisotropy is envisaged from the perspective of the stress ellipsoid shape. The spatial evolutions of the anisotropic invariant map (AIM), anisotropic invariant function, eigenvalues of the scaled Reynolds stress tensor and eccentricities of the stress ellipsoid are investigated at various streamwise distances along the vertical. The data plots reveal that the oblate spheroid axisymmetric turbulence appears near the top of the crest, whereas the prolate spheroid axisymmetric turbulence dominates near the free surface. At the dune trough, the axisymmetric contraction to the oblate spheroid diminishes, as the vertical distance below the crest increases. At the reattachment point and one-third of the stoss-side, the oblate spheroid axisymmetric turbulence formed below the crest appears to be more contracted, as the vertical distance increases. The AIMs suggest that the turbulence anisotropy up to edge of the boundary layer follows a looping pattern. As the streamwise distance increases, the turbulence anisotropy at the edge of the boundary layer approaches the plane-strain limit up to two-thirds of the stoss-side, intersecting the plane-strain limit at the top of the crest and thereafter moving towards the oblate spheroid axisymmetric turbulence.
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Castro, Luma O., Iury O. Castro, Ana Helena G. de Alencar, José Valladares-Neto, and Carlos Estrela. "Cone beam computed tomography evaluation of distance from cementoenamel junction to alveolar crest before and after nonextraction orthodontic treatment." Angle Orthodontist 86, no. 4 (September 17, 2015): 543–49. http://dx.doi.org/10.2319/040815-235.1.
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ABSTRACT Objective: To evaluate the distance between the cementoenamel junction and the alveolar bone crest before and after orthodontic treatment using cone beam computed tomography (CBCT). Materials and Methods: The sample comprised 30 patients with Angle Class I malocclusion and mild to moderate crowding. The study database comprised dental CBCT scans obtained before and after orthodontic treatment. The distance between the cementoenamel junction to the bone crest of the buccal (n = 720) and lingual (n = 720) surfaces was measured in 24 teeth for each patient using a specific software tool (Xoran version 3.1.62). The Wilcoxon test was used for statistical analysis, and the level of significance was set at P < .05. Results: The distance between the cementoenamel junction and the bone crest increased in 822 (57%) of the 1440 surfaces after orthodontic treatment. The buccal surface of the lower central incisors had the greatest frequency of increased distance (75%), and the lingual surface of lateral incisors had the lowest (40%). The distance between the cementoenamel junction and the alveolar bone crest was greater than 2 mm (alveolar bone dehiscence) in 162 (11%) of the 1440 surfaces before orthodontic treatment and in 279 (19%) after treatment. Conclusions: The distance from the cementoenamel junction to the bone crest changed after orthodontic treatment; the distance was greater than 2 mm in 11% of the surfaces before treatment and in 19% after treatment.
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Taignidis, Ioannis, and George Kanellaidis. "Required Stopping Sight Distance on Crest Vertical Curves." Journal of Transportation Engineering 127, no. 4 (August 2001): 275–82. http://dx.doi.org/10.1061/(asce)0733-947x(2001)127:4(275).
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Srebrzyńska-Witek, Agnieszka, Rafał Koszowski, Ingrid Różyło-Kalinowska, and Magdalena Piskórz. "CBCT for estimation of the cemento-enamel junction and crestal bone of anterior teeth." Open Medicine 15, no. 1 (August 3, 2020): 774–81. http://dx.doi.org/10.1515/med-2020-0211.
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AbstractThe aim of the study is to evaluate the usefulness of cone-beam computed tomography (CBCT) in the assessment of the relationship between the cemento-enamel junction (CEJ) and bone crest of the anterior mandibular cortex. The study population comprised 39 males and 61 females, aged 18–71. A GENDEX GXCB-500 machine, i-CAT Vision and CorelDraw 9 software were used. The distances between the CEJ and bone crest at buccal and lingual sides of six anterior mandibular teeth were measured. Descriptive statistical methods, Student’s t-test and ANOVA were used. The mean distance between the bone crest and CEJ was 2.32 mm ± 0.78 mm at the buccal and 2.52 mm ± 0.85 mm at the lingual side. It was found that in males aged over 50 years, the mean distance at the buccal side was 2.84 mm ± 0.79 mm and was significantly higher than in males aged 49 and less – 2.08 mm ± 0.41 mm. The mean distance at the lingual side was 3.28 mm ± 1.08 mm and was significantly lower in the age group of 49 years and less – 2.10 mm ± 0.41 mm. CBCT allows determining the distance between the CEJ and crestal bone margin at buccal and lingual sides. The data provide crucial information for planning orthodontic treatment, implant placement and periodontal therapy.
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Fambro, Daniel B., Kay Fitzpatrick, and Charles W. Russell. "Operating Speed on Crest Vertical Curves with Limited Stopping Sight Distance." Transportation Research Record: Journal of the Transportation Research Board 1701, no. 1 (January 2000): 25–31. http://dx.doi.org/10.3141/1701-04.
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Horizontal and vertical elements of a highway are designed based on an assumed design speed. This concept was developed in the 1930s as a mechanism for designing rural alignments to permit most drivers to operate uniformly at their desired speed. In 1938, AASHO recognized that drivers select a speed influenced by the roadway environment instead of an assumed design speed. Recent research suggests that design speed is no longer the speed adopted by the faster group of drivers but that it has become a value used to establish the sharpness of horizontal and vertical design elements. The objective of this study was to establish the relationship between design and operating speeds for crest vertical curves with limited sight distance. Geometric data and 3,500 paired speeds (speeds at control and crest sections) were collected at 36 sites in 3 states. The results indicated that both the 85th percentile and the mean operating speeds were well above the inferred design speeds of the crest vertical curves for the range of conditions studied and that the lower the design speed the larger the difference between the 85th percentile speed and the design speed. The mean reductions in speed between the control and crest sections tend to increase as available sight distance is decreased; however, the reduction in speed is less than that suggested by current AASHTO criteria.
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Taiganidis, Ioannis. "Aspects of Stopping-Sight Distance on Crest Vertical Curves." Journal of Transportation Engineering 124, no. 4 (July 1998): 335–42. http://dx.doi.org/10.1061/(asce)0733-947x(1998)124:4(335).
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Dr. Nitin Bhalerao. "To Study the Correlation Between the Height & the Quadruple Semitendinosus Graft Diameters." VIMS Health Science Journal 7, no. 1 (March 6, 2020): 1–4. http://dx.doi.org/10.46858/vimshsj.7101.
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Background: Diameter of hamstring graft is variable. Premature tendon amputation occurs because of inability to identify and release all accessory bands. Preoperative prediction of hamstring graft size, number and distance of accessory bands is useful for surgeon. Methodology: This is cross-sectional study included 60 patients. Correlation coefficient (Pearson’s r) was used. T-test was used to compare the variables in both genders. Result: There were correlations between the mean semitendinosus tendon diameters- femoral side (FD) and tibial side (TB) with height of patient (Pearson correlation for FD =0.442 and P< 0.001) (Pearson correlation for TD =0.663 and P< 0.001). For the semitendinosus tendons, the mean number of accessory bands was 1.48. The average distance of the most distal band (D1) to the tibial crest insertion was 6.7 ± 2.04 cm (range 3- 11 cm). In our study, distance of most proximal band to the tibial crest insertion was 11.5 cm (mean 8.5 cm). Conclusion: In our study, positive correlation between the height and the quadruple semitendinosus graft diameters was present. Semitendinosus graft diameters were more in males as compare to females. Third accessory band was present only in males (n=4) in our study. As height of patient increases, distance of distal band (D1) increases from tibial crest. There was inverse correlation between number of accessory bands and distance of the most distal band (D1) insertion. As number of bands less, the more is distance of proximal band from tibial crest.
Dissertations / Theses on the topic "Crest distance"
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Cunliffe, Joanne. "The distance from the contact point to the crest of the bone to predict the presence of a black triangle." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/the-distance-from-the-contact-point-to-the-crest-of-the-bone-to-predict-the-presence-of-a-black-triangle(3c29822e-3068-443a-a017-08bbc86b03d9).html.
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Losing interdental gingival tissue can lead to a phenomemon known as black triangles. The absence of the interdental papilla (the so called 'black triangle disease') can cause patients problems with appearance, phonetics and with the impaction of food. The gingival soft tissues form the framework and the architecture of the dentition and, in the maxillary anterior region of the mouth, play an important role in dental aesthetics. If there is any change to the shape and/or symmetry of the gingivae through developmental, pathologic or iatrogenic factors, there can be a significant and detrimental change in the appearance and balance of the natural dentition and any prosthetic tooth replacement. In this clinical research study, we find that the radiographic measurement of the distance of the contact point to the crest of the bone is a valid and reliable tool to use. This method also adds strength to predicting black triangles as the results are similar to earlier studies and the numbers used in this study was nearly twice as much.
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Mirzoyan, Artak Davit. "Lateral Resistance of Piles at the Crest of Slopes in Sand." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd2088.pdf.
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Graham, Gerhard. "An estimation of seismic anisotropy in the crust from three different time and distance scales." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/12056.
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In this thesis shear-wave splitting is analyzed in shear-wave arrivals from three different time and distance scales to identify the occurrence and extent of anisotropy in the crust. The refracted shear waves recorded by the closely spaced seismic network of the third Turkish Dilatancy Project from regional earthquakes in western Turkey have similar polarizations to those previously observed above local earthquakes, but with less scatter and substantially greater time delays (up to 1.0 s) between the split shear waves. This is interpreted as indicative of the presence of anisotropy in the lower crust with similar anisotropic symmetry to the crack-induced anisotropy of the upper half of the crust. Mine tremors in the deep gold mine of South Africa have seismic magnitudes ranging from ML -4 to ML more than 5. An examination of three-component acceleration and velocity seismograms recorded on the surface above an active gold mine indicates that the shear-wave polarizations have a nearly uniform alignment. This combined with the measured time delays are consistent with shear waves propagating through the effective anisotropy of parallel, vertical microcracks throughout the rockmass. It is concluded that the dry fractures caused by the high stresses during normal mining processes have negligible effect on the shear-wave polarizations at the wavelengths at which shear waves are recorded at the surface. The anisotropy observed at the surface appears to be due to microcracks aligned by the regional stress regime rather than disturbances in the local stress regime due to mining operations. High frequency subsurface recordings of mine tremors that occur in confined volumes surrounding the work face of the mining excavations show shear-wave splitting over distances of a few hundred metres. Plate Carée cylindrical projections of the observed shear-wave polarizations and time delays were compared with theoretical patterns of polarizations and time delays from different synthetic models. From this comparison it became clear that a model containing fluid-filled, non-vertical cracks striking approximately north-south could be used to produce the observed polarizations and time delays to some extent.
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Bhosale, Sheshanath Vishwanath. "Synthesis of bolaamphiphiles and yoctowells with a porphyrin bottom on aminated silica particles containing long distance photoactive Redox pairs and rigid crust /." [S.l. : s.n.], 2004. http://www.diss.fu-berlin.de/2004/341/index.html.
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Bhosale, Sheshanath Vishwanath [Verfasser]. "Synthesis of bolaamphiphiles and yoctowells with a porphyrin : bottom on aminated silica particles containing long distance photoactive Redox pairs and rigid crust / by Sheshanath Vishwanath Bhosale." 2004. http://d-nb.info/973383240/34.
Full textBooks on the topic "Crest distance"
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Jardine, Ray. The Pacific Crest Trail hiker's handbook: Innovative techniques and trail tested instruction for the long distance hiker. 2nd ed. LaPine, OR: AdventureLore Press, 1996.
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The Pacific Crest trailside reader , Oregon and Washington: Adventure, history, and legend on the long-distance trail. Seattle: Mountaineers Books, 2011.
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Kravchenko, Yuriy. Surveying. ru: INFRA-M Academic Publishing LLC., 2017. http://dx.doi.org/10.12737/textbook_5900a29b032774.83960082.
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The contents of the book corre-sponds to the curriculum of surveying for building schools. Including historical and general information about on geodesy, the basic principles of treatment results of geodetic measurements, information about topographic maps and plans and solutions the problems with their use, description of instruments and methods of measurement of angles, distances and excesses on the earth surface, information about horizontal and vertical geo-detic networks, methods for creat-ing and processing survey geodes-ic networks, types and methods of survey, a description of the meth-ods removal projects in nature, description of the geodetic works in prospecting, designing and con-struction of objects capital con-struction.
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Go, Benedict. Pacific Crest Trail data book: Mexico to Canada : a compilation of distances between landmarks, facilites, and other features on the 2,600-mile national scenic trail. Sacramento, CA (5325 Elkhorn Blvd., #256, Sacramento 95842): Pacific Crest Trail Association, 1997.
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Spearing, George G. Dances With Marmots: A Pacific Crest Trail Adventure. Lulu.com, 2005.
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Johnson, Brian. The Pacific Crest Trail: A long distance footpath through California, Oregon and Washington. 2017.
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The Pacific Crest Trail A Long Distance Footpath Through California Oregon And Washington. Cicerone Press, 2010.
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Beltran, Ralph J. Pheochromocytoma. Edited by Kirk Lalwani, Ira Todd Cohen, Ellen Y. Choi, and Vidya T. Raman. Oxford University Press, 2018. http://dx.doi.org/10.1093/med/9780190685157.003.0044.
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Pheochromocytoma is a rare type of neoplasm diagnosed in children. It originates in the adrenal gland and is different from paragangliomas which arise outside the adrenals. Both types of tumors arise from neural crest cells and lead to signs and symptoms related to hypersecretion of catecholamines. Related symptoms include hypertension, tachycardia, episodic headache, sweating, and abdominal pain. These tumors may be associated with multiple endocrine type 2 syndrome, multiple endocrine neoplasia, and von Hippel-Lindau disease, among other hereditary conditions. Pheochromocytomas can be malignant in nature but may be indistinguishable from benign disease histologically and functionally. When malignant, they present with regional invasion or distant metastasis. Conditions presenting as sympathetic overactivity in pediatric patients can resemble pheochromocytoma (i.e., panic disorder, amphetamine consumption).
Book chapters on the topic "Crest distance"
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Mueller, Werner A., Monika Hassel, and Maura Grealy. "Long Distance Wanderers and the Various Fates of the Neural Crest Cells." In Development and Reproduction in Humans and Animal Model Species, 443–53. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-662-43784-1_15.
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Young, Terence. "A Renewal of Our Faith and Ideals." In Heading Out. Cornell University Press, 2017. http://dx.doi.org/10.7591/cornell/9780801454028.003.0008.
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This chapter talks about the subject of backpacking to explore the emergence and meaning of a central infrastructural element of this mode—the long-distance trail. It specifically examines the motivations of Clinton C. Clarke and Warren L. Rogers, whose efforts ultimately led to the creation of the Pacific Crest Trail. Like other campers, Clinton C. Clarke and Warren L. Rogers shared some of their ideas about the value of backpacking with others, but they also pursued personal goals both when on the Pacific Crest Trail and when promoting it. Rogers saw hiking the trail as an activity that recapitulated the frontier experience and could foster Christian virtues. By contrast, Clarke was more of a nationalist who overtly linked backpacking to the character and durability of America.
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Eimeleus, K. B. E. E. "The Effect of Snow on Skis and How They Run1." In Skis in the Art of War, translated by William D. Frank and E. John B. Allen, 33–35. Cornell University Press, 2019. http://dx.doi.org/10.7591/cornell/9781501747403.003.0009.
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This chapter shows how the quality of snow and its behavior are the most influential factors affecting a ski run. Both can change depending on the time of year and the weather. As such, a skier's speed and stamina are closely bound to these two factors. Snow and weather exert more influence than one might think: for example, in nice weather a good skier can cover from 80 to 100 versts in a day but in bad weather one's daily distance could be less. The chapter thus categorizes snow briefly as powdery, loose, granulated, thick-packed crust, thin-layer crust, floury, springtime, and waterlogged. Each of these can have varying effects on skis.
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Harff, J. E., and R. A. Olea. "From Multivariate Sampling To Thematic Maps With An Application To Marine Geochemistry." In Computers in Geology - 25 Years of Progress. Oxford University Press, 1994. http://dx.doi.org/10.1093/oso/9780195085938.003.0027.
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Integration of mapped data is one of the main problems in geological information processing. Structural, compositional, and genetic features of the Earth's crust may be apparent only if variables that were mapped separately are studied simultaneously. Geologists traditionally solve this problem by the "light table method." Mathematical geologists, in particular, D.F. Merriam, have applied multivariate techniques to data integration (Merriam and Sneath, 1966; Harbaugh and Merriam, 1968; Merriam and Jewett, 1988; Merriam and Sondergard, 1988; Herzfeld and Merriam, 1990; Brower and Merriam, 1990). In this article a regionalization concept based on the interpolation of Bayes' probabilities of class memberships is described using a geostatistical model called "classification probability kriging." The problem of interpolation between data points has not been considered in most of the publications on multivariate techniques mentioned above. An attempt at data integration—including interpolation of multivariate data vectors—was made by Harff and Davis (1990) using the concept of regionalized classification. This concept combines the theory of classification of geological objects (Rodionov, 1981) with the theory of regionalized variables (Matheron, 1970; Journel and Huijbregts, 1978). The method is based on the transformation of the original multivariate space of observed variables into a univariate space of rock types or rock classes. Distances between multivariate class centers and measurement vectors within the feature space are needed for this transformation. Such distances can be interpolated between the data points using kriging. Because of the assumptions of multinormality and the fact that Mahalanobis' distances tend to follow a x2 distribution, the distances must be normalized before kriging (Harff, Davis and Olea, 1991). From the resulting normalized distance vectors at each node of a spatial grid, the Bayes' probability of class membership can be calculated for each class. The corresponding grid nodes will be assigned to the classes with the greatest membership probabilities. The result is a regionalization scheme covering the area under investigation. Let X(r) denote the multivariate field of features, modeled as a regionalized variable (RV).
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Lippert, Andreas. "Late Bronze Age helmets with crests on transalpine long-distance trade routes." In Archéologie de la montagne européenne, 253–59. Publications du Centre Camille Jullian, 2010. http://dx.doi.org/10.4000/books.pccj.461.
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Zalasiewicz, Jan. "4. Deep Earth geology." In Geology: A Very Short Introduction, 41–54. Oxford University Press, 2018. http://dx.doi.org/10.1093/actrade/9780198804451.003.0004.
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The distance from the Earth’s surface to the centre of its core is 6,370 kilometres. Humans have penetrated—with difficulty, and the help of sophisticated technology—to a little more than 4 kilometres below ground; and to a depth of 12 kilometres, probing with boreholes. That does not even get us through the Earth’s crust, so what lies in the gigantic realm of the Earth’s depths? ‘Deep Earth geology’ considers the different areas of study of the Earth’s interior, including petrology—the study of igneous, metamorphic, and sedimentary rocks—and magma studies that provide the tangible evidence of the Earth’s history. It also discusses seismology, geophysics, magnetism, and structural geology.
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van Gelder, Geert Jan. "Sexual Violence in Verse: The Case of Jiʿthin, Al-Farazdaq’s Sister." In Violence in Islamic Thought from the Qur'an to the Mongols, 175–91. Edinburgh University Press, 2015. http://dx.doi.org/10.3366/edinburgh/9780748694235.003.0011.
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At some time towards the end of the first/seventh century, a relatively trivial incident took place.1 An Arab of the tribe of Tamīm called Hammām b. Ghālib visited a clan not his own, the Banū Minqar, also belonging to Tamīm. A woman, waking up her daughter called Ẓamyāʾ, found that a snake had crept into her clothes. She cried for help and Hammām, who happened to be nearby, chased the snake away by throwing some dust at it. The snake had probably been attracted by the warmth of the girl’s body; Hammām was attracted to it in turn: he touched the girl and kissed her, but she resisted and he left, making a mocking epigram on her and her clan. When her relatives heard this, they were angry and one of them called ʿAmr (or ʿImrān) b. Murra, who was sent to play a trick upon Hammām’s sister, Jiʿthin. ʿAmr lay in wait for her and approached her unawares when, at night, she left her tent ‘to do her business’. He put his hands on her hip and her leg and dragged her along for some distance. She cried out and when her tribesmen hastened to the scene ʿAmr fled. In another version, there were, in fact, three other men, who together with ʿAmr/ʿImrān dragged Jiʿthin from her tent.
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Oreskes, Naomi. "The Collapse of Thermal Contraction." In The Rejection of Continental Drift. Oxford University Press, 1999. http://dx.doi.org/10.1093/oso/9780195117325.003.0008.
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In 1901, Karl Zittel, president of the Bavarian Royal Academy of Sciences, declared that “Suess has secured almost general recognition for the contraction theory” of mountain-building. This was wishful thinking. Suess’s Das Antlitz der Erde was indeed an influential work, but by the time Suess finished the final volume (1904), the thermal contraction theory was under serious attack. Problems were evident from three different but equally important quarters. The most obvious problem for contraction theory arose from field studies of mountains themselves. As early as the 1840s, it had been recognized that the Swiss Alps contained large slabs of rock that appeared to have been transported laterally over enormous distances. These slabs consisted of nearly flat-lying rocks that might be construed as undisplaced, except that they lay on top of younger rocks. In the late nineteenth century, several prominent geologists, most notably Albert Heim (1849 –1937), undertook extensive field work in the Alps to attempt to resolve their structure. Heim’s detailed field work, beautiful maps, and elegant prose convinced geological colleagues that the Alpine strata had been displaced horizontally over enormous distances. In some cases, the rocks had been accordioned so tightly that layers that previously extended horizontally for hundreds of kilometers were now reduced to distances of a few kilometers. But in even more startling cases, the rocks were scarcely folded at all, as if huge slabs of rocks had been simply lifted up from one area of the crust and laid down in another. Heim interpreted the slabs of displaced rock in his own Glarus district as a huge double fold with missing lower limbs, but in 1884 the French geologist Marcel Bertrand (1847–1907) argued that these displacements were not folds but faults. Large segments of the Alps were the result of huge faults that had thrust strata from south to north, over and on top of younger rocks. August Rothpletz (1853–1918), an Austrian geologist, realized that the Alpine thrust faults were similar to those that had been earlier described by the Rogers brothers in the Appalachians. By the late 1880s, thrust faults had been mapped in detail in North America, Scotland, and Scandinavia.
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Newnham, Robert E. "Diffusion and ionic conductivity." In Properties of Materials. Oxford University Press, 2004. http://dx.doi.org/10.1093/oso/9780198520757.003.0021.
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The phenomenon of atomic and ionic migration in crystals is called solidstate diffusion, and its study has shed light on many problems of technological and scientific importance. Diffusion is intimately connected to the strength of metals at high temperature, to metallurgical processes used to control alloy properties, and to many of the effects of radiation on nuclear reactor materials. Diffusion studies are important in understanding the ionic conductivity of the materials used in fuel cells, the fabrication of semiconductor integrated circuits, the corrosion of metals, and the sintering of ceramics. When two miscible materials are in contact across an interface, the quantity of diffusing material which passes through the interface is proportional to the concentration gradient. The atomic flux J is given by where J is measured per unit time and per unit area, c is the concentration of the diffusing material per unit volume, and Z is the gradient direction. The proportionality factor D, the diffusion coefficient, is measured in units of m2/s. This equation is sometimes referred to as Fick’s First Law. It describes atomic transport in a form that is analogous to electrical resistivity (Ohm’s Law) or thermal conductivity. There are several objections to Fick’s Law, as discussed in Section 19.5. Strictly speaking, it is valid only for self-diffusion coefficients measured in small concentration gradients. Since J and Z are both vectors, the diffusion coefficient D is a second rank tensor. As with other symmetric second rank tensors, between one and six measurements are required to specify Dij , depending on symmetry. The relationship between structure and anisotropy is more apparent in PbI2. Lead iodide is isostructural with CdI2 in trigonal point group.m. The self-diffusion of Pb is much easier parallel to the layers where the Pb atoms are in close proximity to one another. Diffusion is more difficult along Z3 = [001] because Pb atoms have a very long jump distance in this direction. The mineral olivine, (Mg, Fe)2SiO4, is an important constituent of the deeper parts of the earth’s crust.
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Poole, Robert K., and Uldis Kalnenieks. "Introduction to light absorption: visible and ultraviolet spectra." In Spectrophotometry and Spectrofluorimetry. Oxford University Press, 2000. http://dx.doi.org/10.1093/oso/9780199638130.003.0005.
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Light is a form of electromagnetic radiation, usually a mixture of waves having different wavelengths. The wavelength of light, expressed by the symbol λ, is defined as the distance between two crests (or troughs) of a wave, measured in the direction of its progression. The unit used is the nanometre (nm, 10-9 m). Light that the human eye can sense is called visible light. Each colour that we perceive corresponds to a certain wavelength band in the 400-700 nm region. Spectrophotometry in its biochemical applications is generally concerned with the ultraviolet (UV, 185-400 nm), visible (400-700 nm) and infrared (700-15 000 nm) regions of the electromagnetic radiation spectrum, the former two being most common in laboratory practice. The wavelength of light is inversely related to its energy (E), according to the equation: . . . E = ch/ λ . . . where c denotes the speed of light, and h is Planck’s constant. UV radiation, therefore, has greater energy than the visible, and visible radiation has greater energy than the infrared. Light of certain wavelengths can be selectively absorbed by a substance according to its molecular structure. Absorption of light energy occurs when the incident photon carries energy equal to the difference in energy between two allowed states of the valency electrons, the photon promoting the transition of an electron from the lower to the higher energy state. Thus biochemical spectrophotometry may be referred to as electronic absorption spectroscopy. The excited electrons afterwards lose energy by the process of heat radiation, and return to the initial ground state. An absorption spectrum is obtained by successively changing the wavelength of monochromatic light falling on the substance, and recording the change of light absorption. Spectra are presented by plotting the wavelengths (generally nm or μm) on the abscissa and the degree of absorption (transmittance or absorbance) on the ordinate. For more information on the theory of light absorption, see Brown (1) and Chapters 2, 3 and 4. The most widespread use of UV and visible spectroscopy in biochemistry is in the quantitative determination of absorbing species (chromophores), known as spectrophotometry.
Conference papers on the topic "Crest distance"
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Buchner, Bas, Radboud van Dijk, and Arjan Voogt. "The Spatial Analysis of an Extreme Wave in a Model Basin." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29409.
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As a pilot study into the understanding of the occurrence of extreme waves, the spatial development of an extreme wave (Ac/Hs = 1.59) in a model basin was investigated. This wave occurred in a wave spectrum that was not extremely steep and non-linear. It is observed that the extreme wave develops in less than half the wavelength from a relatively normal wave into an extreme crest. The wave crest stays high and constant over a large distance (almost 75m). Linear dispersion is not able to predict the wave propagation towards the observed extreme wave crest. Second order theory improves the prediction of the crest amplitude, but not enough. The crest amplitude is still underestimated. This is confirmed by the plots of the probability of extremes. The linear Rayleigh distribution underestimates the crest amplitudes. The second order distribution follows the measurements much better, but also in this case typically the highest 10 crests in a 3 hours storm are underestimated.
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van Essen, Sanne. "Variability in Encountered Waves During Deterministically Repeated Seakeeping Tests at Forward Speed." In ASME 2019 38th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2019. http://dx.doi.org/10.1115/omae2019-95065.
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Abstract Numerical seakeeping codes for ships at forward speed in waves are often validated or tuned based on experiments, which makes knowledge about the experimental variability essential. This variability was evaluated using repeat tests during a state-of-the-art seakeeping campaign. A steep wave condition over the longitudinal basin axis (waveA) and a less steep oblique wave condition (waveB) were studied. Overall similarity as well as individual crest height, steepnesses and timing variability are discussed, because ship response is not equally sensitive for every point in the wave time series. The variability of the measured incoming wave crests and their timing increases with distance from the wave generator for waveA. The crest height variability for waveB is lower and more constant over the basin length (because the propagation distance to the model is constant in oblique waves and wave breaking is less likely). It was shown that only a small part of the variability close to the wave generator is caused by ‘input’ uncertainties such as the accuracy of the wave generator flap motions, measurement carriage position, their synchronisation and measurement accuracy. The rest of the variability is caused by wave and basin effects, such as wave breaking instabilities and small residual wave-induced currents from previous tests. The latter depend on previous wave conditions, which requires further study. Further work on the influence of the wave variability on the variability of ship motions, relative wave elevation along a ship and impact loads on deck of a ship at forward speed will be presented in a next publication.
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Wong, Wing-Keat (Wayne), Brad Wiebe, Curtis Treen, and John Richmond. "Preserving Pipeline Integrity With Large Diameter Stone Columns at Dead Horse Creek Crossing, Southern Manitoba, Canada." In 2018 12th International Pipeline Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/ipc2018-78651.
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Pipeline integrity has been threatened at the Dead Horse Creek pipeline crossing in southern Manitoba by a slow-moving slope failure with a potential for crest retrogression. The movement zone extends from the slope crest to the bottom of the creek, a vertical distance of about 25 m and is approximately 80 m long from toe to scarp and 100 m wide along the creek. The slope has degraded over time and is controlled by the combination of local geology, which consists of weak colluvium overlying high plastic clay shale, and creek bank erosion and channel degradation. Saturated soil conditions, a function of poor drainage and elevated seasonal precipitation, have exacerbated the problem over the years. The slope movements have been monitored on a regular basis since 2008 and presented an increasing risk to the integrity of multiple pipelines located in two rights-of-way (ROWs) situated within and immediately adjacent to the failing soil mass. The site is surrounded by various infrastructure and recreational areas that are key to the community, and therefore is considered a high consequence area with respect to potential pipeline failures. To manage the risk and protect pipeline integrity, various stress relief and other mitigating measures have been implemented since 2013 [1], culminating in a major slope rehabilitation project undertaken in 2015, which comprised earthworks, drainage and watercourse improvements, and slope stabilization using stone columns. While the use of stone columns to stabilize embankments is not a new technique, it is not commonly used in the pipeline industry and represents another option for geohazard stabilization in the right situations. This paper presents the slope stabilization techniques employed and discusses the challenges of working on an active moving slope confined by a watercourse and live pipeline assets. The positive benefits of the stabilization measures are illustrated through the use of 2D and 3D numerical modelling, and confirmed through an ongoing geohazard management program that includes site inspection and instrumentation monitoring which continues to show improvements in slope performance post construction.
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Canard, Maxime, Guillaume Ducrozet, and Benjamin Bouscasse. "Generation of 3-hr Long-Crested Waves of Extreme Sea States With HOS-NWT Solver." In ASME 2020 39th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/omae2020-18930.
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Abstract The accurate control of wave fields generated in experiments and numerical simulations is of great interest for the ocean engineering community. In the context of wave-structure interactions, the recommended practices of classification societies are indeed based on the definition of a wave spectrum, that needs to be reproduced. The present work intends to address this problem from the numerical point of view, using a Numerical Wave Tank equipped with a wavemaker and an absorbing beach, based on the High-Order Spectral method (HOS-NWT). The challenging case of the generation of 3-hours long-crested extreme sea states is studied in details. An iterative procedure to reproduce a target wave spectrum at a given distance from the wavemaker is proposed. The quality of the sea state obtained is evaluated using several criteria defined from spectral quantities. A validation is first performed with a highly nonlinear but non-breaking sea-state. Statistical crest distributions obtained are compared with the Forristall and Huang distributions [1,2]. Then, the Gulf of Mexico 1,000 Year Return Period wave condition is generated. This corresponds to an extreme sea state with significant wave breaking occurrence. The numerical solver needs to be able to account for this phenomenon [3]. The Tian breaking model [4, 5] is calibrated to realistically reproduce the dissipation due to breaking, with particular attention paid to the spatial discretization, enlightening its significant effect on breaking model actions. Consequences on the iterative correction process are studied. The computed statistical quantities appear to be significantly different changing the spatial discretization, while the wave energy spectrum stands the same. It questions the relevance of the characterization of a sea state with the sole wave energy spectrum.
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Patricelli, B., R. Ruffini, Giuliana Giobbi, Amedeo Tornambe, Gabriella Raimondo, Marco Limongi, L. A. Antonelli, Nicola Menci, and Enzo Brocato. "On the Crust of Neutron Stars: a progress report." In PROBING STELLAR POPULATIONS OUT TO THE DISTANT UNIVERSE: CEFALU 2008, Proceedings of the International Conference. AIP, 2009. http://dx.doi.org/10.1063/1.3141568.
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Bartolini, Lorenzo Maria, Lorenzo Marchionni, Caterina Molinari, and Antonio Parrella. "Effects of Underwater Explosion on Pipeline Integrity." In ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/omae2015-41092.
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Unexploded charges e.g. mines, bombs, torpedoes, etc... are rarely identified at a very early stage of reconnaissance surveys for pipeline route corridors. These ordnances are found during detailed pre-engineering or pre-lay surveys and, sometimes and not surprisingly, during the ordinary surveys performed on the pipeline in service. UXOs represent a hazard for the pipeline as well as for the assets and people involved in the construction phase. An appropriate mitigation plan in areas potentially affected is generally performed, including ordnance removal or mined-area clearance. Large diameter long offshore trunk lines crossing different territorial waters are often exposed to this kind of hazard. As such, pipeline construction and operation call for advanced numerical modelling as unique/valuable tool for providing a quantitative measure of the UXOs related risks. In recent projects the understanding of the underwater explosion process and prediction of damages associated to specific weapon-target engagement are based on the outcome of engineering tools based on finite element modelling. The continuing development of multi-purpose and multi-physics finite element analyses codes facilitates their application, providing sharp and detailed insight into the complex subject of underwater explosive effect and the coupled response of nearby structures. The scope of the structural integrity assessment is to define the minimum distance to be guaranteed between the pipeline and unexploded ordnance to avoid any risk of pipeline damage, as a function of the quantity of explosive. The engineering task of the integrity assessment includes the definition of the relevant conditions for the pipeline whether buried or free spanning, the analysis of the interaction between the gas bubble and shock pressure waves and the cylindrical shape of the pipeline, both as a shell that collapse under a pressure wave and a pipe length that moves laterally and develops bending. The objective is to evaluate the minimum allowable distance of the ordnance from the pipeline, as a function of the explosive quantity and type. In this paper, a series of real cases is presented in order to provide the most relevant parameters characterizing the integrity assessment under the applied load scenario from propagating shock waves. The propagation in water of shock pressure waves induced by the underwater explosion of a spherical charge is performed using finite element modelling, after model verification and validation with respect to the analytical and experimental formulations available in open literature. The outcome from finite element modelling is compared with findings from a simplified model based on modal analysis of the pipe shell – inward bulging and collapse of the pipe section and of the pipe beam – lateral displacement of the impacted stretch and bending at the crest of the buckle.
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Petrova, Petya G., M. Aziz Tayfun, and C. Guedes Soares. "The Effect of Third-Order Nonlinearities on the Statistical Distributions of Wave Heights, Crests and Troughs in Bimodal Crossing Seas." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-50313.
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This paper investigates the effect of third-order nonlinearities on the statistical distributions of wave heights, crests and troughs of waves mechanically generated in a deep-water basin, simulating two crossing systems characterized by bimodal spectra. Observed statistics exhibit various effects of third-order nonlinearities in a manner dependent on both the distance from the wave-maker and the angle between the mean directions of the component wave systems. In order to isolate and demonstrate the effects of third-order nonlinearities by themselves, vertically asymmetric distortions induced by second-order bound waves are removed from the observed time series. It appears then that the distributions of wave crests, troughs and heights extracted from the non-skewed series clearly deviate from the Rayleigh distribution, suggesting that waves are characterized by nonlinear corrections of higher order than the typical of second-order waves. Nonetheless, some models developed for weakly nonlinear second-order waves can still be used in describing wave heights, crests and troughs in mixed seas, provided that relevant distribution parameters are modified so as to reflect the effects of third-order corrections and some basic characteristics of mixed seas.
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Brühl, Markus, and Hocine Oumeraci. "Analysis of Propagation of Long Waves in Shallow Water Using the KdV-Based Nonlinear Fourier Transform (KdV-NLFT)." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-24165.
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Hydraulic model tests and numerical simulations show that long sinusoidal waves that are generated in very shallow waters are not stable but show modifications of the free surface as function of propagation in time and space. First, with increasing distance from the wave maker the wave becomes asymmetric and develops into a bore-shaped wave. Second, with further increasing distance more and more additional wave crests appear from the front of the bore (undular bore). The shallower the water depth, the more additional wave components can be observed. In extremely shallow water, the periodic sine waves completely disintegrate into periodic trains of solitons. At Leichtweiss-Institute for Hydraulic Engineering and Water Resources (LWI), TU Braunschweig, a nonlinear Fourier transform based on the Korteweg-deVries equation (KdV-NLFT) is implemented and successfully applied in Brühl [1] that provides an explanation for this nonlinear phenomenon and allows the prediction of the dispersion and propagation of long sinusoidal waves in shallow water.
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Hasegawa, Kunio, and Hideo Kobayashi. "Failure Stresses for Pipes With Multiple Circumferential Flaws." In ASME/JSME 2004 Pressure Vessels and Piping Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/pvp2004-2712.
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Flaw evaluation for fully-plastic fracture uses the limit load criterion. As stainless steels are high toughness ductile materials, limit load criterion is applicable to stainless steel pipes. When a single circumferential flaw is detected in a stainless steel pipe during in-service inspection, the single flaw is evaluated in accordance with Article EB-4000 in the JSME Code or Appendix C in the ASME Code, Section XI. However, multiple flaws such as stress corrosion cracking are sometimes detected in the same circumferential cress-section in a pipe. If the distance between adjacent flaws is short, the multiple flaws are considered as a single flaw in compliance with combination rules. Failure stress is easily calculated by the equations given by Article EB-4000 or Appendix C. If the two flaws are separated by a large distance, it is not required to combine the two flaws. Each flaw is treated as independent. However, there are no equations for evaluating collapse stress for a pipe containing multiple independent flaws in Article EB-4000 and Appendix C. The present paper focus on a proposal of simple equations for evaluating collapse stresses for pipes containing multiple circumferential part-through wall flaws.
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Di Pace, Luigi, and Antonio Natalizio. "A Radio Toxicity Index for Fusion Waste." In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-4889.
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With current designs of future fusion power plants, it is evident that a significant quantity of operational radioactive waste will be produced over the lifetime of the plant. This waste will be mostly due to the replacement of in-vessel components (IVCs) on a regular basis, currently assumed to be every five years. This potentially large quantity of waste raises issues about its ultimate disposal, particularly the nature of the disposal facility required to accommodate it. The term invessel component includes the divertor and the breeding blanket, the “fuel” in a fusion reactor. In this perspective only, the waste resulting from IVC replacement is analogous to the fuel waste arising from fission power plants, and this comparison, whether justified, or not, could prejudice the fusion waste disposal solution. As fusion in-vessel component waste is significantly and fundamentally different from fission reactor fuel waste, it is essential that the fusion disposal solution be based solely on its needs. To highlight this fundamental difference between the fusion and fission operational waste, a radio toxicity index has been defined, which may prove to be of value in defining appropriate requirements for the disposal of fusion operational waste. Uranium has been the basis of the fission power industry and it is found in nature in concentrations varying, typically, from 0.1 to 1%, and in some cases ore bodies with concentrations up to 25% have been found. Because uranium is a radioactive element, and is quite common in the earth’s crust, it offers an opportunity to be used as a benchmark for comparing potential fusion and fission power reactor radioactive waste. As U-238 is the most abundant isotope of uranium found in nature (>99%), it is proposed that the radio toxicity of U-238 be used to assess the relative radio toxicity of relevant fusion and fission waste. The ratio of the radio toxicity of a given material to that of U-238 is referred to as the radio toxicity index. Therefore, a waste material with a radio toxicity index equal to one would be considered acceptable for disposal in the earth’s crust, in the same manner that uranium tailings are disposed of in the mining industry. The results of studies performed for typical fusion breeder material indicate that there is no compelling economic reason for reprocessing. Furthermore, the radio toxicity index for such materials indicates that there are no technical reasons — i.e., there does not appear to be a need for deep, geological disposal of spent fusion breeder material. On the contrary, the application of the radio toxicity index to spent fission fuel has demonstrated, from a waste disposal perspective, that there are compelling reasons for reprocessing to separate low radio toxicity fission products from the high radio toxicity actinides, which can be reused. This conclusion augurs well for a future fusion power industry and goes a significant distance in demonstrating the potential environmental advantages of fusion power.