Slip and tilt: modeling falls over railings

Falls over railings are frequent case scenarios forensic experts are confronted with. An important issue is the differentiation of accidental and non-accidental falling scenarios. From a biomechanical point of view, this is a challenging task and should be addressed in a multifactorial approach. This work presents a simplified mechanical model in terms of a cranked rod that can be used in cases without relevant dynamic components in terms of pushing or jumping. If the anti-slip and the anti-tilt condition are violated, the possibility for a person to get over a railing should be assumed and investigated in more detail. Because our approach also involves uncertainties, the formulae should be understood to be part of a multifactorial approach. Numerical simulation, experimental reconstruction, injury pattern, and trace analysis can yield additional substantial connecting facts.

Roll tilt self-motion direction discrimination training: First evidence for perceptual learning

Perceptual learning, the ability to improve the sensitivity of sensory perception through training, has been shown to exist in all sensory systems but the vestibular system. A previous study found no improvement of passive self-motion thresholds in the dark after intense direction discrimination training of either yaw rotations (stimulating semicircular canals) or y-translation (stimulating otoliths). The goal of the present study was to investigate whether perceptual learning of self-motion in the dark would occur when there is a simultaneous otolith and semicircular canal input, as is the case with roll tilt motion stimuli. Blindfolded subjects (n = 10) trained on a direction discrimination task with 0.2-Hz roll tilt motion stimuli (9 h of training, 1,800 trials). Before and after training, motion thresholds were measured in the dark for the trained motion and for three transfer conditions. We found that roll tilt sensitivity in the 0.2-Hz roll tilt condition was increased (i.e., thresholds decreased) after training but not for controls who were not exposed to training. This is the first demonstration of perceptual learning of passive self-motion direction discrimination in the dark. The results have potential therapeutic relevance as 0.2-Hz roll thresholds have been associated with poor performance on a clinical balance test that has been linked to more than a fivefold increase in falls.

Influence of Somesthesic Input on Subjective Visual Vertical in Dyslexic Children

Purpose: We explored the perception of subjective visual vertical (SVV) in dyslexic and non-dyslexic age, sex and QImatched.Method: The SVV was evaluated with a laser and with or without foam under the feet. We performed an analysis ofvariance. Post hoc comparisons were made with the Fisher’s least significant differences test (LSD).Results: Our results showed two significant effects for groups and for tilt condition: counterclockwise or clockwisedirection and a significant interaction between group, tilt and somesthesic condition: without and with foam underthe feet. More precisely, SVV response in the tilt counterclockwise condition with foam was found to be significantlyless accurate for the dyslexic group than for the non-dyslexic group. Also, SVV response in the tilt counterclockwisedirection was found to be significantly less accurate for both groups compared to clockwise direction. Moreover, inclockwise direction SVV process was found to be significantly less accurate in dyslexic than in non-dyslexic group.Conclusion: These results suggest that the somesthesic information from foot sole affect SVV perception; such poorSVV responses could be due to an immaturity for heteromodal sensory integration needed in SVV perception.

A Comparison of Cervical Spine Motion After Immobilization With a Traditional Spine Board and Full-Body Vacuum-Mattress Splint

Background: The National Athletic Trainers’ Association (NATA) advocates for cervical spine immobilization on a rigid board or vacuum splint and for removal of athletic equipment before transfer to an emergency medical facility. Purpose: To (1) compare triplanar cervical spine motion using motion capture between a traditional rigid spine board and a full-body vacuum splint in equipped and unequipped athletes, (2) assess cervical spine motion during the removal of a football helmet and shoulder pads, and (3) evaluate the effect of body mass on cervical spine motion. Study Design: Controlled laboratory study. Methods: Twenty healthy male participants volunteered for this study to examine the influence of immobilization type and presence of equipment on triplanar angular cervical spine motion. Three-dimensional cervical spine kinematics was measured using an electromagnetic motion analysis system. Independent variables included testing condition (static lift and hold, 30° tilt, transfer, equipment removal), immobilization type (rigid, vacuum-mattress), and equipment (on, off). Peak sagittal-, frontal-, and transverse-plane angular motions were the primary outcome measures of interest. Results: Subjective ratings of comfort and security did not differ between immobilization types ( P > .05). Motion between the rigid board and vacuum splint did not differ by more than 2° under any testing condition, either with or without equipment. In removing equipment, the mean peak motion ranged from 12.5° to 14.0° for the rigid spine board and from 11.4° to 15.4° for the vacuum-mattress splint, and more transverse-plane motion occurred when using the vacuum-mattress splint compared with the rigid spine board (mean difference, 0.14 deg/s [95% CI, 0.05-0.23 deg/s]; P = .002). In patients weighing more than 250 lb, the rigid board provided less motion in the frontal plane ( P = .027) and sagittal plane ( P = .030) during the tilt condition and transfer condition, respectively. Conclusion: The current study confirms similar motion in the vacuum-mattress splint compared with the rigid backboard in varying sized equipped or nonequipped athletes. Cervical spine motion occurs when removing a football helmet and shoulder pads, at an unknown risk to the injured athlete. In athletes who weighed more than 250 lb, immobilization with the rigid board helped to reduce cervical spine motion. Clinical Relevance: Athletic trainers and team physicians should consider immobilization of athletes who weigh more than 250 lb with a rigid board.

Estimation of Optimum Tilt Angle of PV Panel for Maximum Energy Harvesting

<p>In solar energy conversion system harvesting of maximum energy is necessary in order to maximize the utilization of available energy. The maximum energy from the solar panel can be extracted by keeping solar panel in an optimum tilt angle. Various approaches are available to find optimum tilt condition of the solar panel. In this work two different positions of the panel such as fixed tilt, seasonal tilt were analyzed using isotropic and anisotropic models. Among the various models available in the above said broad category six models such as Liu-Jordan, Koronokis Model, Badescu model, Hay and Davis model, Reindel model, Hay&amp;Davis and Reindel &amp; Klucher combined model are incorperated to predict the monthly average of daily global solar irradiation of the inclined panels held in SASTRA University, Thanjavur (India) location. Statistical tests have been performed in order to evaluate the consequences predicted by the models with the experimental results. Finally a detailed comparison between fixed tilt and seasonal tilt of the panel has been carried out and the suitable model for this location is also suggested.</p>

Estimation of Optimum Tilt Angle of PV Panel for Maximum Energy Harvesting

<p>In solar energy conversion system harvesting of maximum energy is necessary in order to maximize the utilization of available energy. The maximum energy from the solar panel can be extracted by keeping solar panel in an optimum tilt angle. Various approaches are available to find optimum tilt condition of the solar panel. In this work two different positions of the panel such as fixed tilt, seasonal tilt were analyzed using isotropic and anisotropic models. Among the various models available in the above said broad category six models such as Liu-Jordan, Koronokis Model, Badescu model, Hay and Davis model, Reindel model, Hay&amp;Davis and Reindel &amp; Klucher combined model are incorperated to predict the monthly average of daily global solar irradiation of the inclined panels held in SASTRA University, Thanjavur (India) location. Statistical tests have been performed in order to evaluate the consequences predicted by the models with the experimental results. Finally a detailed comparison between fixed tilt and seasonal tilt of the panel has been carried out and the suitable model for this location is also suggested.</p>

Head Orientation Involvement in Assessment of the Subjective Vertical during Whole Body Tilt

The aim of this research was to investigate the involvement of head tilt in the assessment of the subjective vertical during whole body tilt. For inclinations up to 28°, it appears that the whole body tilt gives rise to more important deviations towards its direction (A-effect) than when the tilt was restricted to the head. A multiple regression analysis shows that errors in head-tilt condition partially account for the global errors observed in condition of whole body tilt. Other factors (relative to the degree of inclination) also played a role in the determination of the subjective vertical in whole body tilt but were Jess important than head tilt. These results are highly compatible with the assumption of head orientation as the major determinant in roll-tilt effects.

Generation and Use of Simplified Uplift Shape Functions in Unanchored Cylindrical Tanks

This paper presents a simplified mathematical model for modeling the flexible bottom plate in an unanchored cylindrical liquid storage tank partially uplifted under the static tilt condition. In this model, the cylindrical tank is divided into substructures according to the deformation-resistant mechanisms involved. The modeling of each substructure is based on the Ritz formulation. Numerical results are presented and compared with reported experimental measurements. The results show that the simplified mathematical model is efficient. Practical and accurate results can be obtained using the model leading to a better understanding of the uplift mechanism. The relationship of the uplift behavior with the static tilt angle is also presented and discussed.