Ratio of isotopic parameters δ2H-δ18o in Late Pleistocene and Holocene ice wedge

The subject of this research is the ratio of isotopic parameters of deuterium of heavy oxygen in ice wedges. The authors considered such parameter as inclination of the line of the ration of deuterium of heavy oxygen in ice wedges. Proximal to GMLV (or LLMV) position of isotope values for ice wedge and inclination of the line proximate to 8 suggests that the ice wedge was formed from atmospheric precipitation (winter snow). The article provides separate examples of anomalous deuterium ratios of heavy oxygen with very low ration of line inclination, which in combination with the abnormally low dexc values indicate the indicate isotopic fractionation processes in snow before melting and/or melting snow water before filling frost-cutting cracks. Three author determines the three main types of ratios of deuterium m of heavy oxygen content in ice wedge: a) normal ratio δ2H-δ18O (with line inclination of the ratio proximate to GLMV or LLMW). b) ratio of deuterium  of heavy oxygen to deviation from GLMV or LLMW (with signs of change in the primary isotope signal of atmospheric precipitation), c) anomalous ratio of deuterium of heavy oxygen. It is shown that the first two types  are characteristic to most ice wedge under study in the vast part of the Russian cryolithozone from the European North to the east of Chukotka; the third type is obtained for several Holocene ice wedge in Transbaikal and upper Yenisei River. This may be explained by significant isotope transformation of snow cover in the conditions of distinctly continental climate.

Frontal-Mental Line Inclination Test for assessment of cervical curvature: validation and applicability

Introduction: Alternative testing for X-rays in the assessment of the spine have the advantage of not causing radiation problems, but need to be validated. Objective: To propose a clinical test for assessment of the cervical spine based on the frontal-mental line inclination, identifying its concurrent validity in relation to the gold standard and determining its clinical applicability. Method: The present study was separated into two phases: (1) Test of Frontal-mental Line Inclination’s (TFMLI) validation protocol (evaluation of head position using X-ray analysis and computerized photogrammetry and assessment of cervical curvature using X-ray analysis and the TFMLI) (n = 35); (2) testing the possibility of performing the TFMLI with a universal goniometer (n = 23). Results: In phase 1, for the evaluation of head position, the gold standard and photogrammetry showed high and significant correlation (r = 0.602; p < 0.001). When evaluating cervical curvature, the gold standard and the TFMLI showed high and significant correlation (r = 0.597; p = 0.019). In phase 2, for the evaluation of head position, photogrammetry and goniometry showed high and significant correlation (rs = 0.662; p < 0.001). For the evaluation of cervical curvature, the TFMLI performed with photographs and with goniometry showed almost perfect and significant correlation (r = 0.969; p < 0.001). Conclusion: The TFMLI is suitable for an initial evaluation of the cervical spine posture of individuals with anterior head position and can be applied in clinical practice with the use of a universal goniometer.

Monitoring of Structures by a Laser Pointer. Dynamic Measurement of Rotations and Displacements of the Elastic Line of a Bridge: Methodology and First Test

Deck inclination and vertical displacements are among the most important technical parameters to evaluate the health status of a bridge and to verify its bearing capacity. Several methods, both conventional and innovative, are used for structural rotations and displacement monitoring; no one of these does allow, at the same time, precision, automation, static and dynamic monitoring without using high cost instrumentation. The proposed system uses a common laser pointer and image processing. The elastic line inclination is measured by analyzing the single frames of a HD video of the laser beam imprint projected on a flat target. For the image processing, a code was developed in Matlab&reg; that provides instantaneous rotation and displacement of a bridge, charged by a mobile load. An important feature is the synchronization of the load positioning, obtained by a GNSS receiver or by a video. After the calibration procedures, a test was carried out during the movements of a heavy truck maneuvering on a bridge. Data acquisition synchronization allowed to relate the position of the truck on the deck to inclination and displacements. The inclination of elastic line was obtained with a precision of 0.01 mrad. The results demonstrate the suitability of the method for dynamic load tests, control and monitoring of bridges.

Changes of ankle inclinations after total knee arthroplasty

Aim: To evaluate the changes in ankle joint line inclination in patients who had total knee arthroplasty due to degenerative osteoarthritis. Material/Method: Sixty-two knees (with a mean age of 71,66±6,78 years, follow-up 52,34±27,42 months) which had undergone total knee arthroplasty between November 1996 and May 2014 were included in this retrospective study. The knee joint line orientations (KJLO) of the prosthesis and ankle joint line inclination (AJLI) relative to the floor were evaluated on postoperative standard standing long-leg X-rays. The AJLI relative to the floor was defined as the angle between the tangent to the subchondral plate of the talus and the horizontal grid line on radiographs. In order to determine the effects of KJLO and high varus on AJLI, patients were divided into two each groups that were pre-operative mechanical axes (MA) as <20° (n=35, group1) and >=20° (n=27, group2) and post-operative MA <3° (n=32, group a) and >=3° (n=30, group b). In addition, the changes in AJLI were compared between each group. The patients were regrouped as either <=3° (n=28, group i) or >3° (n=34, group ii), in terms of the postoperative KJLO. Inclination angles of the prosthesis were compared between each groups. Statistical analysis was performed with SPSS v18. Results: Mean MA of pre-operative and post-operative were 16,35±6,56° and 3,92±3,35°, respectively. All ankle inclinations were lateralized. AJLI, were significantly decreased from pre-operative mean 7,37°±3,19° to post-operative mean 3,71°±2,22° (p<0,0001). The mean of change was 3,65°±3,03°. However, pre-operative AJLIs were significantly increased in high varus group (group1: 6,34°±2,54°, group2: 8,70°±3,48°, p=0,003); post-operative AJLIs did not differ significantly (group1: 3,55°±2,36°, group2: 3,92°±2,05°, p=0,516) with respect to the MA. The changes in preop-postop AJLI’s were significantly higher in high varus group again (p=0,009). When the KJLO groups were compared, pre-operative AJLIs were significantly different (group i: 6,25°±2,33°, group ii: 8,29°±3,53°, p=0,004) while post-operative AJLIs did not differ significantly (group i: 3,46°±2,38°, group ii: 3,92°±2,08°, p=0,489). Conclusion: Pre-operatively high varus knees also had high ankle varus, hence ankle deformity was corrected by the restoration of the optimal lower limb aligment. Obtaining parallel orientation of the components relative to the ground, restored the AJLI. Pre-operative planning and convenient implantation of the components lead to achieve optimum knee orientation which restored the ankle joint line orientation independent from mechanical axes. Not only the goal of optimum mechanical axes but also optimum knee joint line orientation’s importance was demonsrated.

Optimal Design of Bourdon Gage Mechanisms

The paper deals with the optimization of lever-segment gear-pinion mechanisms used in the construction of Bourdon gage manometers. The number of teeth of the pinion (which is rigidly attached to the manometer hand) is used as an objective function in order to maximize accuracy. Design variables are the gear-pinion center distance and center line inclination and various constraints are imposed in order to satisfy operating conditions and constructive limits. An example is presented showing that the objective function is maximized by the highest feasible value of the center distance and is less sensitive to variations of the center line inclination.

Glacier Sliding Down an Inclined Wavy Bed With Friction

The effects of frictional tangential traction combined with regelation on the basal sliding of a temperate glacier down an inclined wavy bed are examined. Two friction models are treated. First, a Coulomb law model having the assumptions that sliding occurs everywhere and that the tangential traction is proportional to the normal pressure. Secondly, a velocity power law in which the tangential traction is proportional to a power of the slip velocity. The ice motion is approximated by steady slow Newtonian flow and the bed undulation about a mean bed-line has a maximum slope ∊ ≪I. Flow solutions are constructed as perturbations (in powers off ∈) of the plane laminar flow corresponding to non-slip on the mean bed-line assuming that the ice remains everywhere in contact with the bed; that is, no cavitation takes place. If the normal traction is predicted to be tensile over part of the bed, implying that cavitation has occurred, then a new solution is needed in which the ice base over cavities is traction-free. Since the cavity sections and profile of the free ice base are then part of the overall solution, an intricate mixed boundary-value problem is set up for the flow and the present analysis is inadequate.For a sinusoidal bed the perfect-slip (zero tangential traction) solution predicts compressive normal traction everywhere on the bed provided that the mean bed-line inclination α (to the horizontal) is less than a critical value αe which is of order ε. For greater values of α including a range of order ∊, the normal traction is tensile on some parts of the bed, and a solution with cavitation is needed. If the tensile sections are relatively small it is expected that the resulting cavitation will not change the overall solution significantly. However, the Coulomb friction solution has extensive zones of tensile traction for all values of α, so that extensive cavitation would occur. In contrast, the velocity-power friction solution has compressive traction everywhere on the bed for α ⩽αe=0(I) provided that the ice depth is not too large, and also for deep glaciers for α ⩽αe=O∊ Furthermore, the predicted basal sliding velocity varies much less with the length scale of the bed undulation than in the perfect-slip solution, and is smaller.

Glacier Sliding Down an Inclined Wavy Bed With Friction

The effects of frictional tangential traction combined with regelation on the basal sliding of a temperate glacier down an inclined wavy bed are examined. Two friction models are treated. First, a Coulomb law model having the assumptions that sliding occurs everywhere and that the tangential traction is proportional to the normal pressure. Secondly, a velocity power law in which the tangential traction is proportional to a power of the slip velocity. The ice motion is approximated by steady slow Newtonian flow and the bed undulation about a mean bed-line has a maximum slope ∊ ≪I. Flow solutions are constructed as perturbations (in powers off ∈) of the plane laminar flow corresponding to non-slip on the mean bed-line assuming that the ice remains everywhere in contact with the bed; that is, no cavitation takes place. If the normal traction is predicted to be tensile over part of the bed, implying that cavitation has occurred, then a new solution is needed in which the ice base over cavities is traction-free. Since the cavity sections and profile of the free ice base are then part of the overall solution, an intricate mixed boundary-value problem is set up for the flow and the present analysis is inadequate.For a sinusoidal bed the perfect-slip (zero tangential traction) solution predicts compressive normal traction everywhere on the bed provided that the mean bed-line inclination α (to the horizontal) is less than a critical value αewhich is of order ε. For greater values of α including a range of order ∊, the normal traction is tensile on some parts of the bed, and a solution with cavitation is needed. If the tensile sections are relatively small it is expected that the resulting cavitation will not change the overall solution significantly. However, the Coulomb friction solution has extensive zones of tensile traction for all values of α, so that extensive cavitation would occur. In contrast, the velocity-power friction solution has compressive traction everywhere on the bed for α ⩽αe=0(I) provided that the ice depth is not too large, and also for deep glaciers forα ⩽αe=O∊ Furthermore, the predicted basal sliding velocity varies much less with the length scale of the bed undulation than in the perfect-slip solution, and is smaller.