SMARTPHONE USAGE TIME, POSTURE OF THE CERVICAL REGION, AND ASSOCIATED FACTORS IN TEENAGE UNIVERSITY STUDENTS

Objective: This study aimed to assess the relationship between smartphone usage time and postural alignment in teenage university students and the associated factors. Methods: We carried out a cross-sectional study with 133 teenage university students (18-19 years old) between April and November 2018 in Fortaleza, Ceará, Brazil. Questionnaires were used to collect information on socioeconomic status, health conditions, smartphone usage time and level of physical activity. The alignment of the cervical region was assessed using photogrammetry in anatomical position and while texting on the smartphone. Horizontal alignment of the head (HAH), horizontal alignment of the acromion (HAA) and vertical alignment of the head (VAH) were measured. Bivariate and multivariate analyses were performed to check for factors associated with smartphone usage time (>6 hours a day). Results: There were higher rates of girls (66.9%; n=89), people in the lower social class (71.4%; n=95), frequent drinkers (66.9%; n=89), people who complained of headache (83.5%; n=111) and people who used smartphones for more than 6 hours a day (72.9%; n=97). The multivariate analysis showed an association of smartphone usage time (>6 hours a day) with cervical anteriorization, estimated by measuring the VAH (OR=1.053; p=0.007 – left side), female gender (OR=2.729; p=0.046), frequent drinking (OR=2.636; p=0.038) and complaint of headache (OR=5.617; p=0.002). Conclusions: There was a high percentage of adolescents who excessively used smartphones for more than 6 hours a day. Prolonged smartphone use was associated with female gender, alcohol consumption, headache and changes in cervical alignment.

Investigation of Motorcycle Trajectories in 2-lane Horizontal Curves

Most of the road design guidelines assume that the vehicles traverse a trajectory that coincides with the midline of the traffic lane. Based on this assumption the thresholds of various features are determined such as the maximum permissible side friction factor. It is therefore important to investigate the extent to which the trajectory of the vehicles is similar to the horizontal alignment of the road or substantial differences exist. To this end, a naturalistic riding study was designed and executed with the use of an instrumented motorcycle which measured the position of the motorcycle with great accuracy in a rural 2-lane road segment. The derived trajectories were then plotted against the horizontal alignment of the road and compared with the 3 consecutive elements which form a typical horizontal curve i.e., the entering spiral curve, the circular curve, and the exiting spiral curve. Linear equations were developed which correlate the traveled curvatures with the distance of each horizontal curve along the road segment under investigation. The process of the data revealed that the riders differ their trajectory compared to the alignment of the road. However, in small radius horizontal curves is more likely to observe curvatures that are similar to the geometric one. Moreover, the riders perform more abrupt maneuvres in the first part of the horizontal curves while they straighten the handlebars of the motorcycle before the end of the curve. The present paper aims to shed light on the behavior of motorcycle riders on horizontal curves and hence to contribute to the reduction of motorcycle accidents, particularly the single-vehicle ones.

Study on hydrodynamic characteristics and influence factors of asphalt pavement runoff

A hydrodynamic model is developed for rainfall runoff on asphalt pavement using two-dimensional shallow water equations. A simple yet precise expression is presented to compute flow velocity in order to alleviate the problems associated with numerical instabilities due to small water depths of thin sheet flow. The developed model performed well against measured data and numerical results in two segments. Then, the model is applied to study the influence of highway horizontal alignment, drainage manner, rainfall pattern, surface roughness and geometric parameters on pavement runoff. The results demonstrate that: (i) the influence of highway horizontal alignment on pavement runoff is nonsignificant, while that of drainage manner and the pavement surface roughness is significant. Great differences are observed in flow depth under concentrated drainage and overflow drainage conditions, especially in the area beyond 6 m away from the highway center axis; (ii) remarkable differences in maximum flow depth and peak runoff are presented under uneven and even rainfall conditions, while no great differences are found under three uneven rainfall conditions (front type, center front type and back front type); (iii) the sensitivity of the geometric parameters to the maximum flow depth from strong to weak is cross slope, width, slope length, and longitudinal slope under overflow drainage condition; while that is width, slope length, longitudinal slope and cross slope under concentrated drainage condition.

The New 1 kN·m Torque Standard Machine in National Institute of Metrology, China

A 1 kN-m deadweight torque standard machine is established in National Institute of Metrology, China. The torque range is 5N·m-1200 N·m. The deadweights utilized in the machine can generate the torque of 1200 N·m, 600N·m, 360N·m, 240N·m, 120N·m and 60 N·m, respectively. The torque can be applied both in clock-wise and counter clock-wise direction in sequencial loading process. The aerostatic bearing is introduced to the torque standard machine in order to eliminate the influence of friction. The symmetric V type rotor and stator are used to provide the reliable support both in axial and radial direction. The material of the lever arm is invar alloy, performing with the minimum deformation with the change of the ambient temperature. The counter torque part will make the precise adjustment to make a horizontal alignment of the lever arm. The relative standard uncertainty of the torque generated by the machine is less than 1e-5.

Automatic Identification of Roadway Horizontal Alignment Information Using Geographic Information System Data: CurvS Tool

This paper introduces CurvS, a web-based tool for researchers and analysts that automatically extracts, visualizes, and analyzes roadway horizontal alignment information using readily available geographic information system roadway centerline data. The functionalities of CurvS are presented along with a brief background on its methodology. The validation of its estimation results are presented using actual horizontal alignment data from two different roadway types: Route 83, a two-lane two-way rural roadway in New Jersey and I-80, a freeway segment in Nevada. Different metrics are used for validation. These are identification rates of curved and tangent sections, overlap ratio of curved and tangent sections between estimated and actual horizontal alignment data, and percent fit of curve radii. The validation results show that CurvS is able to identify all the curves on these two roadways, and the estimated section lengths are significantly close to the actual alignment data, especially for the I-80 freeway segment, where 90% of curved length and 94% of tangent section length are correctly matched. Even when curves have small central angles, such as the ones in Route 83, CurvS’s estimations covers 71% of curved length and 96% of tangent section length.

Postural Analysis of Male Football Athletes from Different Age Levels of Training

Introduction: The definition of body posture involves a relative arrangement of body parts. Football is the most popular sport in the world with an injury rate of 4.47 injuries per 1000 hours of play/training per athlete. Photogrammetry is a valid and reproductive method for evaluating postural differences with quantitative and accurate results. The aim of this study is to present a postural analysis of children and young football players, using photogrammetry. Method: The sample consisted of 263 athletes (ages between 4 and 18 years) where, through the photographic register and use of SAPO® software the main postural deviations of the children were calculated and subsequently analyzed descriptively in the IBM SPSS software. Results: The results obtained show deviations in point A1 - alignment of the acromion (21.4% to 50% of athletes on the right (R) and 16.7% to 40.5% of athletes on the left (L); A2 - alignment of the anterosuperior iliac spine (42.9% of athletes to (R) and 14.3% to 64.9% to the left (L); A3 alignment of tibia tuberosities (27.9% to 55% of athletes (R), 27% to 48.5% of athletes (L); A4 and A5 – angle Q (R and L) (50% to 91% of athletes with tendency to knee varus); A6 – horizontal alignment of the pelvis (tendency to hyperlordosis of 28% for juveniles with an average deviation of -15.4° ± 7.7). Conclusion: The postural analysis of the athletes allows a better knowledge about the most frequent deviations that, over time, can become painful, being important an intervention and specific planning at this level, trying to prevent future injuries.

Bilevel Optimization of Intercity Railway Alignment

Intercity railway transit is the primary way to transfer passengers and freight over long distances on land. The design of an intercity railway alignment is usually challenging and complex because of great topographic variations and intersections with many existing geographic objects. This paper presents a bilevel optimization model for intercity railway alignment (BRAO) following the horizontal-vertical alignment design philosophy. The upper level is the horizontal alignment optimization, while the nested lower level is the vertical alignment optimization. A multistage augmented differential evolution algorithm is adopted for the solution at both levels. BRAO could generate corridor alignment, initial alignment, and optimal alignment through different allocations of the number and boundaries of decision variables. A real-world case study of railway design is conducted to verify the effectiveness of the BRAO model based on a geographic information system.

Bi-facial Open-Space Photovoltaic Systems versus Conventional Systems using Mono-facial Modules

As part of a scientific work within the solar company Sunfarming GmbH, the aim was to find out whether bi-facial modules on open spaces deliver better results economically than conventional mono-facial solar modules. In this context, an already installed 750 kWp PV system with mono-facial solar modules was compared directly with a structurally identical PV system with bi-facial modules, which, however, does not exist in practice but was only simulated with PV software. The second part of the investigation includes the comparison of four different assembly systems or elevation variants in order to determine the system with the best relationship between system yield and costs. The final result of the first investigation showed that the use of bi-facial modules reduced the specific costs per kWh by approximately 5 %. In order to improve this effect, the use of compact assembly systems is recommended, e.g. five rows of modules per table with horizontal alignment.