No abstract

This study identified perceived physical activity (PA) enablers and barriers among a racially/ethnically and geographically diverse group of older adults. Data were from 42 focus groups conducted with African Americans, American Indians, Latinos, Chinese, Vietnamese, and non-Hispanic Whites (hereafter Whites). Constant-comparison methods were used to analyze the data. Common barriers were health problems, fear of falling, and inconvenience. Common enablers were positive outcome expectations, social support, and PA program access. American Indians mentioned the built environment and lack of knowledge about PA as barriers and health benefits as an enabler more than participants in other groups. Whites and American Indians emphasized the importance of PA programs specifically designed for older adults. Findings suggest several ways to promote PA among older people, including developing exercise programs designed for older adults and health messages promoting existing places and programs older adults can use to engage in PA.

No abstract

Calibration, Microsimulation, Traffic models,

This is a repository copy of A platoon based cooperative eco-driving model for mixed automated and human-driven vehicles at a signalised intersection.

A new family of garnet compounds, Ca 2 LnZr 2 Ga 3 O 12 (Ln=La, Y, Lu, Gd) have been synthesized by high-temperature solid-state reaction method. The crystal structures were characterized by the X-ray diffraction (XRD) and refined by the Rietveld method. The photoluminescence properties, morphology, CIE value, quantum efficiency and thermal stability of Ca 2 LaZr 2 Ga 3 O 12 :Ce 3+ phosphors were investigated in detail to evaluate the use in w-LEDs. The photoluminescence results revealed that these phosphors have a broad excitation band in the blue region ranging from 400 nm to 470 nm and a broad green emission band centered at about 515 nm.The above results indicated that the phosphors could be effectively excited by blue light and may have potentials to be served as green-emitting phosphors for application in w-LEDs.

High-quality white light-emitting diodes (w-LEDs) are mainly determined by conversion phosphors and the enhancement of cyan component that dominates the high color rendering index. New phosphors (Lu 2 M)(Al 4 Si)O 12 :Ce 3+ (M = Mg, Ca, Sr and Ba), showing a cyan-green emission, have been achieved via the co-substitution of Lu 3+ -Al 3+ by M 2+ -Si 4+ pair in Lu 3 Al 5 O 12 :Ce 3+ to compensate for the lack of cyan region and avoid using multiple phosphors. The excitation bands of (Lu 2 M)-(Al 4 Si)O 12 :Ce 3+ (M = Mg, Ca, Sr and Ba) show a red-shift from 434 to 445 nm which is attributed to the larger centroid shift and crystal field splitting. The enhanced structural rigidity associated with the accommodation of larger M 2+ leads to a decreasing Stokes shift and the corresponding blue-shift (533 → 511 nm) in emission spectra, along with an improvement in thermal stability (keeping ∼93% at 150 °C). The cyan-green phosphor Lu 2 BaAl 4 SiO 12 :Ce 3+ enables to fabricate a superhigh color rendering w-LED (R a = 96.6), verifying its superiority and application prospect in high-quality solid-state lightings.

Headway fluctuation and bus bunching are commonly observed in transit operations, while holding control is a proven strategy to reduce bus bunching and improve service reliability. A transit operator would benefit from an accurate forecast of bus propagation in order to effectively control the system. To this end, we propose an 'ad-hoc' bus propagation model taking into account vehicle overtaking and distributed passenger boarding (DPB) behaviour. The latter represents the dynamic passenger queue swapping among buses when bunching at bus stops occurs and where bus capacity constraints are explicitly considered. The enhanced bus propagation model is used to build the simulation environment where different holding control strategies are tested. A quasi first-depart-first-hold (FDFH) rule is applied to the design of headway-and schedule-based holding control allowing for overtaking, with the objective to minimise the deviation from the targeted headway. The effects of control strategies are tested in an idealized bus route under different operational setting and in a real bus route in Guangzhou. We show that when the combined overtaking and queue-swapping behaviour are considered, the control strategies can achieve better headway regularity, less waiting time and less on-board travel time than their respective versions without overtaking and DPB. The benefit is even greater when travel time variability is higher and headway is smaller, suggesting that the control strategies are preferably deployed in high-frequency service.