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Acute Angle (acute + angle)
Selected AbstractsEarthquake effects on the Anatolian Motorway, TurkeyGEOLOGY TODAY, Issue 2 2009Hayrettin Koral On 12 November 1999, the Anatolian earthquake in Turkey damaged a partially completed motorway viaduct. The viaduct, which is some 2.3 km long, passes over the Düzce Fault as the route starts its ascent into the Turkish plateau. The Düzce Fault is a northern offshoot of the main North Anatolian Fault (NAF) Zone, and cuts the viaduct at an acute angle of 15 degrees. Movements along the NAF have been identified as the prime cause of the earthquake. Alternatives to a viaduct crossing had been considered in the feasibility stage, but were ruled out because of the rugged landslide-influenced terrain and requirements for an even motorway ascent grade. The relative displacement of around 120 equally spaced piers identified the nature of the ground displacements and gave an indication as to the likely areas of foundation damage. This article examines the damage caused to the viaduct during the earthquake. [source] Kinematic optimal design of a paramill: A multi-SP deviceJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 6 2004Jun-Ho Lee In this paper, a manipulability analysis of a new parallel-type rolling mill, named "paramill," in its conceptual design stage is investigated. The paramill considered uses two Stewart platforms (SPs) in opposite directions for the generation of 6 degree-of-freedom motions of individual work-rolls. The objective of this new approach is to pursue an integrated control of the strip thickness, strip shape, pair-crossing angle, uniform wear of the rolls, and tension of the strip. The forward/inverse kinematics problems are formulated. Two main kinematic parameters, the size of the base and the acute angle made by two neighboring joints for a given size of the work-roll, have been determined in the way that the force and moment transmission from the actuators to the work-rolls is maximized. © 2004 Wiley Periodicals, Inc. [source] Thermal Expansion of ,-Yttrium DisilicateJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 1 2004Koichiro Fukuda Crystals of ,-Y2Si2O7 (space group P121/c1) were examined using high-temperature powder X-ray diffractometry to determine their unit-cell dimensions from 296 to 1473 K. The lattice deformation induced by thermal expansion was investigated using matrix algebra analysis to determine the directions and magnitudes of the principal distortions (,i, i= 1,2, and 3). The directions of ,1 and ,3 were defined by the acute angle ,1c, which linearly decreased from 5(2)° to ,5.5(3)° with increased temperature from 504 to 1473 K. The ,2 -axis invariably coincided with the crystallographic b -axis. The magnitudes of ,1 and ,2 steadily increased to, respectively, 1.0061(1) and 1.0068(1) during heating to 1473 K, while ,3 remained almost constant for the entire temperature range. The mean principal distortion, ,m (= (,1+,2+,3)/3), steadily increased to 1.0044(1) with increased temperature to 1473 K. The coefficient of mean linear thermal expansion (,) was derived from the mean principal strain (,m - 1) as ,= (,m - 1)/,T. The temperature dependence was determined to be ,= 2.03 times 103+ 1.36(T - 296) (10 -9 K -1). Provided that the rule-of-mixtures holds for the Y2Si2O7/Y2SiO5 composites as protective coating on SiC substrates, the volume fractions of 0.72-0.77 (70,75 mass%) would be necessary for the Y2Si2O7 component to match the ,-values of both materials. [source] The influence of age, sex, population group, and dentition on the mandibular angle as measured on a South African sampleAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 4 2009Anna C. Oettlé Abstract The mandibular angle is measured in physical anthropological assessments of human remains to possibly assist with the determination of sex and population affinity. The purpose of this investigation was to establish how the mandibular angle changes with age and loss of teeth among the sexes in South African population groups. The angles of 653 dried adult mandibles from the Pretoria Bone Collection were measured with a mandibulometer. Males and females of both South African whites and blacks were included. To compensate for imbalances in numbers among subgroups, type IV ANOVA testing was applied. No association was found between age and angle within either of the populations, within sexes, or within dentition groups. The angle was the most obtuse in individuals without molars and with an uneven distribution of molars, and most acute in the group with an even distribution of molars on both sides. Statistically significant differences (P < 0.001) were found in the angle between the two population groups and sexes in the overall sample as well as in the subgroup with absent molar teeth (P = 0.003 for sex, males more acute angle, and P = 0.001 for population group, blacks more acute angle), although a very large overlap existed. No significant differences could be demonstrated between the sexes or populations within the subgroups with molars. We concluded that the loss of molars, especially if complete or uneven, has a considerable effect on the mandibular angle. In the assessment of human remains, the mandibular angle is not very usable in determining sex. Am J Phys Anthropol, 2009. © 2009 Wiley-Liss, Inc. [source] Upper pole access for complex lower pole renal calculiBJU INTERNATIONAL, Issue 6 2004Monish Aron Authors from New Delhi assessed the efficacy of superior pole access for complex lower pole calyceal calculi; they found this to be the best way of approaching such complex stones, allowing faster and better clearance with a single puncture. The second paper in this section is from authors from the UK who set out to describe the frequency of renal symptoms and complications in patients with tuberous sclerosis complex, and to relate the history of renal haemorrhage with renal lesions identified on renal scan. OBJECTIVES To assess the efficacy of superior pole access for complex lower pole calyceal calculi. PATIENTS AND METHODS In all, 102 patients with complex inferior calyceal calculi were included in a prospective unrandomized study. Complex inferior calyceal calculi were defined as multiple calculi in two or more inferior calyces of the lower polar group, with each calyx draining through a separate infundibulum and at an acute angle to each other. In 33 patients (32%; group 1) an inferior calyceal puncture was made and in 69 (68%; group 2) access was obtained through a superior calyceal puncture. The stone-free rates, decrease in haemoglobin, operative duration, requirement for additional tracts and second procedures in the two groups were compared. RESULTS Stone clearance rates and blood loss values were better in group 2, although they were not significantly different. The mean operative duration, number of tracts required and the re-look procedure rate was significantly less in group 2. Two patients (3%) in group 2 had hydrothorax related to supracostal puncture and required chest tube insertion. CONCLUSIONS Superior calyceal puncture (supracostal or infracostal) affords optimum access to complex inferior calyceal stones, providing faster and better clearance with a single puncture, and less requirement for second-look procedures. [source] Primary growth and morphological markers of interannual growth limits in Cupressaceae from PatagoniaBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 3 2004JAVIER GROSFELD The present study shows experimentally that primary growth of the native Patagonian Cupressaceae Austrocedrus chilensis (D. Don) Pic.-Serm et Bizz., Fitzroya cupressoides (Molina) I. M. Johnst. and Pilgerodendron uviferum (D. Don) Florin is potentially continuous. External morphological markers of interannual growth limits have been identified for the main axes of these species after several years of observation. Such limits correspond with axis portions in which internodes are relatively short and leaves have a small distal free end forming an acute angle with the axis. The causality of these results and their utility for studying the productivity, adaptation to different environments, population management and conservation of these threatened species are discussed. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 146, 285,293. [source] Optic disc appearance and retinal temporal vessel arcade geometry in high myopia, as based on follow-up data over 38 yearsACTA OPHTHALMOLOGICA, Issue 5 2010Hans C. Fledelius Abstract. Purpose:, To discuss (i) optic disc appearance and (ii) the retinal course of the temporal vessel arcade in a longitudinal series of high myopia patients followed between the ages of 16 and 54. Methods:, Thirty-nine individuals from a 1948 Copenhagen birth cohort (n = 9243) who had myopia of ,6 to ,15 D when aged 14 years were invited for current follow-up exams with 7,10-year intervals. Fundus photos were available from up to five occasions over 38 years, and single eye photo collages were studied with respect to posterior pole changes over time. Results:, Fifty-two eyes with high myopia were available. (i) Contrary to the expected predominance of large flat optic discs in long eyes, more than half the eyes in the sample had neurodiscs that were perceived to be small; many were also oval/kinked/tilted and with minimum or absent physiological cups. Among the fellow eyes with unilateral high myopia only one out of the 10 discs appeared as small/tilted. (ii) By age, a more acute angle between upper and lower temporal retinal vessel trunks was found in 12/20 eyes with adult myopia progression (change over time 5,23°) and in 6/24 eyes with stable myopia. In the myopia-progression subgroup, peaking of the angle was correlated with myopia degree, myopia increase and axial elongation. Conclusion:, Contrary to clinical expectation, we found neurodiscs that appeared to be small and dense in eyes with high myopia. We further discussed the eventual peaking of the angle between the temporal vessel arcades that is sometimes observed in high myopia. Occasionally, literature on myopia reports the presence of small and tilted discs whereas no mention was found of the issue of temporal vessel arcade peaking. [source] Parameters affecting retentive force of conus crownsJOURNAL OF ORAL REHABILITATION, Issue 3 2004M.A. Güngör summary, The aim of this study was to determine the values of the retentive forces of the telescopic crowns. At the first step of the study, the samples having different heights and angles were compared in relation to retentive force. At the second step, the samples were subjected to removal procedures having a pre-determined speed, force and number. The obtained retention values were compared. Ninety dies were prepared in order to measure the retention of the conus crowns. The removal tests were performed with the insertion/separation device. The speed of the test device was 100 cm min,1 providing the placement of the pieces with 5 kgf in 100, 200, 300, 500, 1000, 5000 and 10 000 cycles. The mean of the retention values of the changes of the angles were found to be statistically different (P < 0,01). According to the results of the variant analysis, the differences in the changes of the height were statistically significant (P < 0·01). The differences between the changes of the number of procedures of all groups were statistically significant (P < 0·01). The number of procedures, height and angle interactions were statistically insignificant (P = 0·758). According to the results of this study, the effect of the angle and height factors in terms of retention among the groups were not independent of each other. In equal angles, as the height increased, increased retention measurements were obtained. In more acute angles, the increase in retention was more obvious. It was also found that an accessory device was necessary to maintain retention capabilities after a long-term use. [source] Rotafolia songziensis gen. et comb. nov., a sphenopsid from the Late Devonian of Hubei, ChinaBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2005DE-MING WANG A sphenopsid from the Upper Devonian (Famennian) Xiejingsi Formation, south-western Hubei Province, China, previously named as various species in Sphenophyllum, Hamatophyton, Bowmanites and Sphenophyllostachys, is now reinvestigated and assigned to a new taxon, Rotafolia songziensis gen. et comb. nov. Its ribbed axes are anisotomous and possess slightly expanded nodes. Lateral axes are inserted at nodes on main axes. Whorls of much divided vegetative leaves are attached at nearly right angles to nodes of basal axes, and at acute angles to nodes of terminal axes. There are six leaves per whorl. The terminal strobilus includes a central axis and verticils of fertile units. Each fertile unit consists of a bract and numerous sporangia. The margin of the elongate-cuneate bract bears a distal and many lateral elongate segments. Clusters of elongate sporangia are abaxially attached to the base of the bract at the same level. The axis has an actinostele, composed of a three-ribbed, exarch primary xylem and radial secondary xylem. Although Rotafolia songziensis closely resembles Hamatophyton verticillatum in axis character, leaf morphology and primary xylem type, they are quite different in strobilar structure. Taxonomically, Rotafolia is placed in the order Sphenophyllales by three well-defined characters: 1) whorled appendages; 2) ribbed protosteles; 3) exarch primary xylem maturation. © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society, 2005, 148, 21,37. [source] | |||||||||||||