Smaller Maximum Research Articles

Negative Thermal Expansion Behavior Enabling Good Electrochemical‐Energy‐Storage Performance at Low Temperatures

Metal‐ion batteries (such as lithium‐ion batteries) are very popular energy‐storage devices nowadays. However, low temperatures cause their poor electrochemical kinetics and performance, significantly limiting their wide applications in cold environments. Here, we propose that electrochemical energy‐storage materials with negative‐thermal‐expansion (NTE) behavior can enable good low‐temperature electrochemical performance, which becomes a new strategy to tackle the low‐temperature issues of metal‐ion batteries. LiTi2(PO4)3 (LTP) with an a‐direction thermal expansion coefficient of −1.1 × 10−7 K−1 is used as a model material. As the temperature decreases, the transverse vibration of O atoms not only increases the transverse distances among O atoms connected to Li/Ti atoms, but also widens the Li+‐transport channels and enlarges Li+‐insertion sites along the [12 ‐1] direction, which are mainly controlled by the lattice parameter a. Consequently, carbon‐coated LTP (C‐LTP) retains good electrochemical performance at −10 °C, including fast Li+ diffusivity (84% of that at 25 °C), large capacity (96% of the theoretical capacity), and superior rate capability (83% capacity retention at 5C vs. 0.5C). Moreover, the more open crystal structure of LTP at the lower temperature allows smaller maximum unit‐cell‐volume expansion, resulting in better cycling stability of C‐LTP at −10 °C (96.8% capacity retention over 1000 cycles at 2C).

Negative Thermal Expansion Behavior Enabling Good Electrochemical-Energy-Storage Performance at Low Temperatures.

Metal-ion batteries (such as lithium-ion batteries) are very popular energy-storage devices nowadays. However, low temperatures cause their poor electrochemical kinetics and performance, significantly limiting their wide applications in cold environments. Here, we propose that electrochemical energy-storage materials with negative-thermal-expansion (NTE) behavior can enable good low-temperature electrochemical performance, which becomes a new strategy to tackle the low-temperature issues of metal-ion batteries. LiTi2(PO4)3 (LTP) with an a-direction thermal expansion coefficient of -1.1 × 10-7 K-1 is used as a model material. As the temperature decreases, the transverse vibration of O atoms not only increases the transverse distances among O atoms connected to Li/Ti atoms, but also widens the Li+-transport channels and enlarges Li+-insertion sites along the [12 -1] direction, which are mainly controlled by the lattice parameter a. Consequently, carbon-coated LTP (C-LTP) retains good electrochemical performance at -10 °C, including fast Li+ diffusivity (84% of that at 25 °C), large capacity (96% of the theoretical capacity), and superior rate capability (83% capacity retention at 5C vs. 0.5C). Moreover, the more open crystal structure of LTP at the lower temperature allows smaller maximum unit-cell-volume expansion, resulting in better cycling stability of C-LTP at -10 °C (96.8% capacity retention over 1000 cycles at 2C).

Alternative uses for crushed stone products generated to meet the raw material needs of asphalt production in Hungary

In Hungary, quarries that produce stone products for wearing courses of asphalt pavements also produce a significant amount of 0/4, 0/8 and 4/8 mm fractions. Because of Hungary’s pavement design and asphalt production practices, these fractions do not have a suitable market and can thus be sold on alternative markets. Purpose. To demonstrate the feasibility of using crushed fractions of 0/4 and 0/8 mm in the protection and base layers of asphalt pavements instead of sandy gravel with 0/22 mm fraction. Methodology. The CBR method was applied to evaluate the comparability of characteristics such as particle size distribution and load-bearing capacity. The combination of the Proctor and CBR tests allowed someone to compare the expected technological characteristics of the dominant and alternative aggregate types, such as their sensitivity to water and load-bearing capacity. Findings. The results demonstrated that the performance characteristics of conventionally used sandy gravel with a size of 0/22 mm can be achieved and exceeded by crushed material with much smaller maximum grain sizes – i.e., 0/4 and 0/8 mm. Originality. The paper presents an original study that contradicts the industry’s actual decline of crushed stone (0/4 and 0/8 mm fractions) for asphalt pavement protection layers. The potential effectiveness and functionality of the proposed coating are demonstrated through convincing tests, and thus new data and insights are introduced into the Hungarian construction industry’s practice. Practical value. The test results greatly helped in achieving the high demands of the private industrial project by proposing an alternative variant of crushed stone of 0/8 mm fraction rather than the originally planned dominant sand and gravel material. The asphalt paving experience on this site clearly demonstrated the viability of the alternative aggregate option for Hungarian roads.

Non-contrast enhanced silent MR angiography to evaluate hemodynamics and morphology of unruptured intracranial aneurysms: a comparative computational fluid dynamics study

BackgroundSilent MR angiography (silent MRA) is a new generation of non-contrast enhanced angiography with outstanding advantages in visualizing cerebrovascular lesions and the follow-up after endovascular treatment for intracranial aneurysms (IAs)....

Species of Dickinsonia Sprigg from the Ediacaran of South Australia

AbstractAn iconic member of the Ediacara Biota, Dickinsonia Sprigg is one of few such taxa with multiple species. Here we use Gaussian finite mixture models to assess the validity of species distinctions for this genus. Our results indicate that the five described species of Dickinsonia from the Ediacara Member, South Australia are better classified as two based on multiple approaches. Two different methods for dimension reduction both provide strong support for two groups, with overlapping but distinct mixture models. The variable selection method produces the most biologically realistic clusters, indicating that the two species can be primarily differentiated based on the greater relative size of the anterior most unit of Dickinsonia costata Sprigg compared with Dickinsonia tenuis Glaessner & Wade. Despite differences in aspect ratio and number of modules, both species regulated growth to maintain overall shape. The greater likelihood of preservation of a midline and an irregular outer margin in D. tenuis highlights differential structural integrity and flexibility. Co‐occurrence in the Ediacara Member indicates that both species occupied the same environments and temporal distribution. Smaller maximum and average size for D. costata, combined with higher abundance, may suggest a comparatively shorter lifespan and increased rates of reproduction.

Selective Doping to Controllably Tailor Maximum Unit-Cell-Volume Change of Intercalating Li+ -Storage Materials: A Case Study of γ Phase Li3 VO4.

Capacity decay of an intercalating Li+‐storage material is mainly due to the its particle microcracks from stress‐causing volume change. To extend its cycle life, its unit‐cell‐volume change has to be minimized as much as possible. Here, based on a γ‐Li3VO4 model material, the authors explore selective doping as a general strategy to controllably tailor its maximum unit‐cell‐volume change, then clarify the relationship between its crystal‐structure openness and maximum unit‐cell‐volume change, and finally demonstrate the superiority of “zero‐strain” materials within 25–60 °C (especially at 60 °C). With increasing the large‐sized Ge4+ dopant, the unit‐cell volume of γ‐Li3+ x Ge x V1− x O4 becomes larger and its crystal structure becomes looser, resulting in the decrease of its maximum unit‐cell‐volume change. In contrast, the doping with small‐sized Si4+ shows a reverse trend. The tailoring reveals that γ‐Li3.09Ge0.09V0.91O4 owns the smallest maximum unit‐cell‐volume change of 0.016% in the research field of intercalating Li+‐storage materials. Consequently, γ‐Li3.09Ge0.09V0.91O4 nanowires exhibit excellent cycling stability at 25/60 °C with 94.8%/111.5% capacity‐retention percentages after 1800/1500 cycles at 2 A g−1. This material further shows large reversible capacities, proper working potentials, and high rate capability at both temperatures, fully demonstrating its great application potential in long‐life lithium‐ion batteries.

Impact of Radial Lands on the Reduction of Torque/Force Generation of a Heat-Treated Nickel-Titanium Rotary Instrument

This study investigated the impact of a one-sided radial-landed cross-sectional design of a heat-treated nickel-titanium rotary instrument (JIZAI, MANI, Japan; JZ) on torque/force generation and canal-shaping ability, using an experimental non-landed instrument (non-landed JZ) for comparison. Both instruments had tip sizes of 25 and 0.04 or 0.06 taper and were similar in metallurgy and geometry, except for the presence/absence of a radial land. Twenty J-shaped simulated resin canals were instrumented in a two-instrument single-length sequence using an automated root canal instrumentation device with a torque/force analyzing unit. Pre- and post-instrumentation images of the resin canals were analyzed for canal-centering ability at 0–3 mm from the apex. The mean centering ratio was not significantly different between JZ and non-landed JZ (p > 0.05). In the 2nd instrumentation, JZ showed a significantly smaller torque compared with the non-landed JZ (p < 0.05). Regardless of instrumentation sequence, JZ showed a significantly smaller maximum upward force, representing screw-in force (p < 0.05), and a larger maximum downward force (p < 0.05) than the non-landed JZ. JZ generated smaller screw-in forces and had similar canal-centering ability compared with the non-landed JZ.

Robust Simultaneously Stabilizing Decoupling Output Feedback Controllers for Unstable Adversely Coupled Nano Air Vehicles

The plants of nano air vehicles (NAVs) are generally unstable, adversely coupled, and uncertain. Besides, the autopilot hardware of a NAV has limited sensing and computational capabilities. Hence, these vehicles need a single controller referred to as Robust Simultaneously Stabilizing Decoupling (RSSD) output feedback controller that achieves simultaneous stabilization, desired decoupling, robustness, and performance for a finite set of unstable multi-input-multi-output adversely coupled uncertain plants. To synthesize a RSSD output feedback controller, a new method that is based on a central plant is proposed in this paper. Given a finite set of plants for simultaneous stabilization, we considered a plant in this set that has the smallest maximum $v-$gap metric as the central plant. Following this, the sufficient condition for the existence of a simultaneous stabilizing controller associated with such a plant is described. The decoupling feature is then appended to this controller using the properties of the eigenstructure assignment method. Afterward, the sufficient conditions for the existence of a RSSD output feedback controller are obtained. Using these sufficient conditions, a new optimization problem for the synthesis of a RSSD output feedback controller is formulated. To solve this optimization problem, a new genetic algorithm based offline iterative algorithm is developed. The effectiveness of this iterative algorithm is then demonstrated by generating a RSSD controller for a fixed-wing nano air vehicle. The performance of this controller is validated through numerical and hardware-in-the-loop simulations.

A Study on the Status and Thermal Environment Improvement of Ceiling-Embedded Indoor Cooling and Heating Unit

In this study, a basic study was performed to analyze the seasonal temperature status of a research room in the Global Environment Research Building, where ceiling-embedded indoor units are installed to study the room temperature status of the building, as well as to improve its thermal environment. In addition, a direction for improvement of the indoor thermal environment in the winter was proposed through a CFD (computational fluid dynamics) simulation and was proven by an additional experiment. Through the results of this study, it appeared that if the ceiling-embedded indoor unit was installed in the small indoor space without considering the thermal vulnerability of its perimeter boundary, the air temperature of the upper part was greatly different from that of the bottom part in the winter. Based on the PMV measurement result, the case that used both FCUs and convectors showed 1.33, the biggest maximum and minimum difference, and the case that used all FCUs, convectors and circulating fans showed 0.68, the smallest maximum and minimum difference. Therefore, it was considered that the operating method suggested in the room used in this study would improve not only the temperature stratification but also the thermal comfort. Hence, in this study, as a means to improve the stratification, convectors were installed to minimize the effect of the external thermal environment, and angle-controllable air flowing fans were installed to mitigate the stratification distribution. With such a result, it was intended to present essential data for the improvement of the thermal environment, as well as the conservation of heating energy in the winter, by reviewing the use of the ceiling-embedded indoor units in the future.

Magnetocaloric properties of Gd2MoO6 prepared by a simple and fast method

The experimental study of the specific heat, magnetic susceptibility, and magnetization of Gd2MoO6 powder sample was performed in the temperature range between 0.4 K and 300 K in the magnetic fields up to 9 T. Powder sample was prepared via nonconventional mechanochemical/thermal process from powdered oxide precursors. Magnetic ion Gd3+ with spin S = 7/2 is responsible for the magnetic properties. The specific heat study in zero magnetic field revealed two anomalies; a phase transition to the ordered state at TN1 ≈ 0.98 K and a smaller maximum at TN2 ≈ 0.6 K. Relatively high magnetic density 6.85 g/cm3 of Gd2MoO6 predetermines this compound as potential magnetocaloric material with a high cooling performance at cryogenic temperatures. A large conventional magnetocaloric effect was found around 3 K with magnetic entropy change −ΔSmax ≈ 44 J/(kg K) (300 mJ/(Kcm3)) for magnetic field change from 9 T down to zero with a refrigerant capacity of 464 J/kg. Maximal temperature change -ΔTad ≈ 23.8 K was found for initial temperature Tinit ≈ 29.9 K for the mentioned change of magnetic field. Alternating susceptibility measurements revealed the presence of two relaxation channels in Gd2MoO6 existing in two different time scales ≈ 10-3 s and ≈ 1 s.

Finite element analysis of different locking plate fixation methods for the treatment of ulnar head fracture

BackgroundUlnar head fractures are increasingly higher with the growing proportion of the elderly people. Failure to achieve a stable anatomic reduction of ulna head fracture may lead to a distal radioulnar joint (DRUJ) dysfunction and nonunion of the distal radius. Due to the lack of the postoperative reporting outcomes and the biomechanical studies, it has not been well established about the optimal management of the comminuted distal ulna head fracture. Hence, the purpose of this study is to use finite element analysis to explain the advantages and disadvantages of ulnar-side locking plate fixation compared with dorsal-side locking plate fixation and its screw arrangement in the treatment of ulnar head fractures.MethodsFE models of the ulnar head fracture and the models of ulnar-side locking plate and dorsal-side plate with two or three distal screws was constructed. In order to simulate forces acting on the ulnar and the osteosynthesis material during daily-life activity in subjects who underwent reconstructive surgery, we applied three loading conditions to each model, viz. 20 N axial compression, 50 N axial compression, 1 N∙m torsion moment, 1 N∙m lateral bending moments, and 1 N∙m extension bending moments. Under these conditions, values of the von Mises stress (VMS) distribution of the implant, peak VMS, the relative displacement of the head and shaft fragments between the fracture ends and the displacement and its direction of the models were investigated.ResultsThe stress values of ulnar-side plates were lower than those of dorsal-side plates. And the ulnar-plate fixation system also has smaller maximum displacement and relative displacement. When adding a screw in the middle hole of the ulnar head, the values of model displacement and the peak stress in fixation system are lower, but it may evidently concentrate the stress on the middle screw.ConclusionsIn conclusion, our study indicated that ulnar-side locking plates resulted in a lower stress distribution in the plate and better stability than dorsal-side locking plates for ulnar head fracture fixation. Adding an additional screw to the ulnar head could increase the stability of the fixation system and provide an anti-torsion function. This study requires clinical confirmation of its practicality in the treatment of ulnar head fractures. This study requires clinical confirmation as to its practicality in the treatment of ulnar head fracture.

Effect of Different Levels of Energy Diet Restriction on Energy Balance, Leptin and CL Development, Vascularization, and Function in South American Camelids.

The objective was to determine the effect of energy diet restriction on energy balance, systemic leptin and corpus luteum (CL) vascularization, development, and function in South American camelids. In experiment 1, adult llamas were randomly assigned to receive a diet of 70% of their maintenance energy requirements (MER) (Restricted group, n = 7) or fed ad libitum (Control group, n = 7) during 28 days. Body live weight (BLW) and body condition score (BCS) were recorded, blood samples were collected every 2 weeks to measure plasma leptin concentrations, and energy metabolites were quantified. In experiment 2, adult alpacas were randomly assigned to receive a diet of 40% MER for 21 days (Restricted group, n = 7) or fed ad libitum (Control group, n = 7). Then, ovulation was induced with gonadorelin acetate (day = 0), and trans-rectal ultrasonography (7.5 MHz) was performed using B and Doppler mode to record the diameter of the pre-ovulatory follicle, ovulation, CL diameter, and vascularization from Days 0 to 13. Blood samples were collected every 48 h from Days 1 to 13 to quantify plasma leptin and progesterone concentrations. In experiment 1, energy diet restriction of 70% MER did not affect plasma leptin concentration and metabolic parameters of the Restricted group. In experiment 2, the Restricted group had a lower BCS (p < 0.001), a smaller diameter of the CL on Days 5 and 7 (p < 0.05), and a smaller maximum diameter of the CL (10.2 ± 0.6 mm) than the Control group (12.1 ± 0.6 mm; p = 0.04). Low energy restriction of 70% MER for 28 days did not affect the energy balance of llamas (Experiment 1). Moderate energy restriction of 40% MER for 21 days negatively affected energy balance (BCS), and CL development but not its vascularization, leptin, and progesterone concentrations. These species must be submitted to longer periods or a higher level of energy restriction to impair ovarian function.

SO007OVERHYDRATION TREATMENT WITH COMBINED CRYSTALLOID AND COLLOID PD SOLUTION

Abstract Background and Aims Peritoneal dialysis (PD) fluids used colloid or crystalloid solutions to achieve ultrafiltration. Here we presented our clinical experience with the intraperitoneal (IP) use of mixed solutions (MS) (crystalloid plus colloid) to treat overhydration. Method We studied the kinetics of 4-hour single-dwell exchange using 2L MS in 3 different sessions. We analysed IP fluids and IP pressure at 0,30,60,120 and 240 min plus blood samples at 0, 120 and 240 min. MS kinetics were compared with standard 4-hour 3.86 % glucose (GS) exchange. MS composition. We modified a single-dwell exchange of 2L Icodextrin (Extraneal, Baxter®) by adding a continuous 50% glucose infusion (50g Glucose per 100mL) in an aseptic technique through infusion pump (42 ml/h) over 4 hours. Results MS exchange induced a progressive increase in IP pressure with an inverse decrease in IP sodium, without significant changes in IP glucose or osmolarity. MS exchanges were well tolerated without side effects (total 25 sessions). We did not observe any remarkable change in bloods samples during the MS exchange. The combination fluid enhanced net ultrafiltration (mean 1030 ml) compared with GS (650 ml). Although the net glucose dispensed was slightly higher with MS (79 g MS vs 77.2 g GS), similar net glucose absorption was observed (49.8 g MS vs 49.9g GS) and smaller maximum intraperitoneal glucose levels (1739 mg/dL at 120 min with MS vs 2695 mg/dL with GS at 0 min). GS induced a faster initial reduction in dialysate sodium concentration while MS maintained the sodium sieving over 4-hour dwell enhancing net ultrafiltration due to sustained IP glucose concentration. Conclusion The combination fluid could be a new strategy to enhance ultrafiltration in PD patients, leaded by colloid osmosis at the beginning of PD exchange maintained by crystalloid osmosis. Figure (A) Intraperitoneal kinetics of MIXED SOLUTION for IP sodium (Na+ PF), Osmolarity PF and intraperitoneal pressure. (B, C, D) Comparison between MIXED SOLUTIONS (black line) vs Glucose solution 3,86 % (gray line) intraperitoneal kinetcs for sodium (B), intraperitoneal pressure (C) and glucose (D).

Electro-caloric effects in the BaTiO3-based solid solution ceramics

Electro-caloric effect (ECE) was investigated in BaTiO3 (BT)-based solid solution ceramics, Ba(Zr,Ti)O3 (BZT), Ba(Sn,Ti)O3 (BST) and (Ba,Ca)(Zr,Ti)O3 (BCZT) with the composition near an invariant critical point (ICP). The samples were fabricated by the solid-state reaction method and the ECE was obtained by an indirect measurement. The 12BZ–88BT, 9BS–91BT, and 32BCT–68BZT samples showed the best polarization–electric field (P–E) hysteresis characteristics at room temperature and displayed dielectric peaks at 46, 58, and 66 °C, which are the Curie temperatures. With increasing temperature, the P–E loops changed from typical ferroelectric square shapes to paraelectric slanted shapes in the BT-based solid solution ceramics. The adiabatic temperature change due to the ECE (ΔTECE) showed the maximum values of 0.46 °C at 80 °C, 0.5 °C at 65 °C, and 0.47 °C at 75 °C, respectively, in the 12BZ–88BT, 9BS–91BT, and 32BCT–68BZT samples. The BT-based solid solution ceramics showed smaller maximum ΔTECE, but broader ΔTECE peaks at nearer room temperature than the BT ceramic. The enhancement of the ECE due to the multi-phase coexistence was not observed in BT-based solid solutions with the compositions near an invariant critical point (ICP) at which several phases coexist.

The clinicopathological characteristics and survival outcomes of endometrial carcinoma coexisting with or arising in adenomyosis: A pilot study

Little is known about the epidemiological and clinicopathological characteristics of endometrial endometrioid carcinoma (EEC) coexisting with or arising in adenomyosis (EEC-A or EEC-AIA) due to their rarity. This study compared EEC-A and EEC-AIA with endometrial carcinoma without adenomyosis. Cases of endometrial cancer treated at the study center from June 1, 2010, to June 1, 2017, were reviewed. The epidemiological, clinicopathological characteristics and survival outcomes were compared among three groups of endometrioid subtypes: group A, stage IA endometrial carcinoma patients without coexisting adenomyosis; group B, patients with EEC-A; and group C, patients with EEC-AIA. Among the 2080 patients reviewed, groups A, B, and C included 1043, 230 and 28 patients, respectively. Patients in group A and group B had similar clinicopathological and survival outcomes. Patients in group C were significantly younger and had less gravidity and parity than patients in groups A and B. More tumors from group C were grade 1, and they had a smaller maximum diameter and less mismatch repair deficiency than those from groups A and B. After a median follow-up of 57.0 months, the 5-year disease-free survival (DFS) rates of groups A, B and C were 96%, 91% and 100% (p = 0.045), respectively; the 5-year overall survival (OS) rates were 98%, 93% and 100%, respectively (p = 0.001), in the Kaplan-Meier analysis. However, these difference disappeared in a subgroup of stage IA patients in univariate and multivariate analysis. Cox regression analysis in stage IA patients also revealed no significant differences in survival outcome across the three groups. In conclusion, EEC-AIA exhibited specific clinicopathological characteristics that were probably associated with favorable survival outcomes. The characteristics and survival outcomes of EEC-A were similar to those of EEC without adenomyosis in stage IA patients.

Effect of Mass-Center Position of Spinal Segment on Dynamic Performances of Quadruped Bounding with a Flexible-Articulated Spine

Driven by the layout design of devices arranged on the spine of quadruped robot which has a symmetry spine with a flexible joint, we explore the effect of mass-center position of spinal segment (MCPSS) on dynamic performances of quadruped bounding. A simplified model is introduced with MCPSS set as an independent parameter. Periodically quadruped bounding motions are generated to calculate different dynamic performances related to different MCPSS at the low, medium, and high horizontal speeds, respectively. The results indicate MCPSS corresponding to the optimal or suboptimal dynamic performances mainly gather at two positions: the hip joint and the geometric center of spinal segment. MCPSS near the hip joint leads to the largest stride period, stride length, and spinal oscillation-margin at all speeds. The smallest duty factor can also be obtained at the medium and high speeds. These improved inherent characteristics offer advantages in leg-orientation control and fast movement effectively. MCPSS near the geometric center of spinal segment brings the best self-stability, the smallest mass-center vertical fluctuation, and the smallest maximum foot-end force at all speeds, which should greatly enhance resistances to vertical jitters and reduce torque-demands of joint-drivers. This study should give useful suggestions to robot designs in reality.

Exogeneous Spatial Cueing beyond the Near Periphery: Cueing Effects in a Discrimination Paradigm at Large Eccentricities.

Although visual attention is one of the most thoroughly investigated topics in experimental psychology and vision science, most of this research tends to be restricted to the near periphery. Eccentricities used in attention studies usually do not exceed 20° to 30°, but most studies even make use of considerably smaller maximum eccentricities. Thus, empirical knowledge about attention beyond this range is sparse, probably due to a previous lack of suitable experimental devices to investigate attention in the far periphery. This is currently changing due to the development of temporal high-resolution projectors and head-mounted displays (HMDs) that allow displaying experimental stimuli at far eccentricities. In the present study, visual attention was investigated beyond the near periphery (15°, 30°, 56° Exp. 1) and (15°, 35°, 56° Exp. 2) in a peripheral Posner cueing paradigm using a discrimination task with placeholders. Interestingly, cueing effects were revealed for the whole range of eccentricities although the inhomogeneity of the visual field and its functional subdivisions might lead one to suspect otherwise.

Non-Dimensional Analysis of Thermal Effect on Skin Exposure to an Electromagnetic Beam

We consider the problem of inducing withdrawal reflex on a test subject by exposing the subject’s skin to an electromagnetic beam. Heat-sensitive nociceptors in the skin are activated wherever the temperature is above the activation temperature. Withdrawal reflex occurs when the activated volume reaches a threshold. We non-dimensionalize the problem to write the temperature as the product of a parameter-free function of non-dimensional variables and a function of beam parameters. This formulation allows studying beam parameters without knowing skin material parameters. We examine the effects of spot size, total power and distribution type of the electromagnetic beam on 3 quantities at reflex: 1) the time to reflex, 2) the maximum temperature increase, and 3) the total energy consumption. We find that the flat-top beam is the best, with the lowest energy consumption and the smallest maximum temperature increase. The Super-Gaussian beam is only slightly inferior to the flat-top. The Gaussian beam has by far the worst performance among these three.

Reinforcement Effect of Inclined Prestressed Concrete Pipe Piles on an Inclined Soft Foundation

The embankment slope is vulnerable to slip and collapse, when prestressed concrete pipe (PCP) piles are used to reinforce the inclined soft foundation to bear the load of the embankment. Accordingly, this study puts forward new programs for strengthening embankment foundation with inclined, rather than vertical, PCP piles. Based on an actual engineering accident with embankment slope collapse, this study establishes a finite element model, accompanied by analysis of engineering characteristics and reinforcement effects of the foundation. The main conclusions are drawn as follows: (1) when a pile‐supported foundation is used to strengthen the inclined soft foundation, PCP piles in the lower part of the embankment are subjected to bending moments, with their maximum value appearing in the upper part of the PCP pile at the embankment slope foot. During the embankment filling, the maximum pile bending moment may reach the ultimate bending load, resulting in bending failure accompanied with large lateral displacement and even slope collapse. The maximum horizontal displacement of the foundation is located at the foot of the embankment slope. (2) Reinforcement using inclined PCP piles contributes to smaller maximum pile body bending moments than that using vertical PCP piles and loading berms, and such contribution is enhanced when the inclination angle of PCP piles in the lower part of the slope gets larger. Therefore, inclined PCP piles with high angles are optimum in improving the overall stability of the foundation. (3) Compared with vertical PCP piles, inclined PCP piles contribute to smaller horizontal displacement and vertical settlement in foundation reinforcement, which means better reinforcement effects. Moreover, as the inclination angle of PCP piles increases, the maximum displacement decreases rapidly, associated with greatly enhanced lateral stability.

Intersegmental body coordination during obstacle avoidance in a virtual environment

Introduction Postural coordination is essential for implementing efficient obstacle circumvention strategies during locomotion. While virtual environments (VEs) are increasingly used to replicate real-life conditions and safely assess or train patients on complex locomotor tasks, the extent to which coordination strategies in VEs differ from that observed in the physical environment (PE) remains to be elucidated. Material and methods The objective was to estimate the extent to which coordination strategies in the VE differ from the PE. Healthy young participants (n = 10) were assessed while walking towards a target and avoiding pedestrians approaching from different directions (left, centre, right) in a VE vs. PE. The VE, identical in size and appearance to the PE, was viewed using a HTC VIVE head-mounted display (HMD). Centre of mass trajectory (CoMt), as well as head, thorax and pelvis yaw, were measured using a Vicon system. Results In both environments, participants reoriented their body segments towards their heading direction during obstacle circumvention. In the PE, the reorientation sequence started with the head (2.94 ± 0.04 m from obstacle), followed by the trunk (2.74 ± 0.03 m), pelvis (2.71 ± 0.04 m) and CoMt (2.64 ± 0.04). In the VE, reorientation started with the pelvis (2.97 ± 0.03 m) and trunk (2.95 ± 0.03 m), followed by the head (2.79 ± 0.04 m) and CoMt (2.77 ± 0.04 m). Smaller maximum head reorientation (Δ = 1.72 ± 0.67; P Conclusion Head reorientation was smaller and delayed in the VE, which could be due to the characteristics of HMD and a need for longer visual fixation on the obstacle/target. These differences should be considered when using VR in locomotor rehabilitation.