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Hallux valgus (HV) is a foot deformity most commonly found in female and elderly patients. Its symptoms include foot pain, impaired gait patterns, poor balance, and falls in older adults. Recently, various HV orthoses have been introduced in the market, however, they have many shortcomings, such as high costs, unclear therapeutic effects, and effects on push-off of the foot during walking. The present study employs 3D printing technology to develop an HV orthosis and uses motion analysis to investigate the effects of wearing it. This study recruited 12 individuals with HV, who were asked to first perform a static HV measurement without orthosis, followed by a dynamic HV measurement using a Vicon motion analysis system in three trials. The results indicated that wearing the 3D-printed orthosis significantly corrected the HV angle by approximately 11° during static standing and by approximately 9° during dynamic walking. However, no significant difference was observed during use of the orthosis in terms of the ground reaction force. The obtained results demonstrate that the 3D-printed HV orthosis is an effective device for correcting the HV angle during static standing and dynamic walking, especially during the push-off phase of gait.

In the present study, carbon-dots (CDs) were derived from the thermal oxidation of an agricultural waste, bitter tea residue, to obtain different sp2/sp3 ratios and electronic structures for metal sensing. The CDs obtained from calcination at 700 °C exhibited the highest photoluminescence (PL) quantum yield (QY) of 11.8% among all the samples treated at different temperatures. These CDs had a high degree of graphitization, which resulted in a strong π-π* electron transition, and hence in a high QY. The strong photoluminescence of the CDs could be used to sense the metal ions Ag+, Sr2+, Fe2+, Fe3+, Co2+, Ni2+, Cu2+, and Sn2+ by monitoring their PL intensity at an excitation wavelength of 320 nm. The metals inhibited the PL intensity in the order Ag+ > Fe2+, Fe3+, Ni2+ > Sr2+, Co2+, Cu2+, Sn2+, which demonstrated that the CDs exhibited high metal ion detection capability and selectivity. The detection of Fe3+ using CDs was performed in the range of 10–100 ppm with a LOD (limit of detection) value of 0.380 ppm. Theoretical calculations demonstrated that Ag+, Sr2+, and Sn2+ induced charge transfer excitation and that Fe2+ and Ni2+ induced d-d transitions via complexation with the sp2 clusters. The charge transfer excitation and d-d transitions hindered the π-π* transition of the sp2 clusters, leading to a quenching effect. On the other hand, Li+, Na+, and K+ ions did not alter the π-π* transition of the sp2 clusters, resulting in a negligible quenching effect. In summary, the oxidation level and electronic structure of CDs derived from bitter tea residue could be tailored, and the CDs were shown to be a facile, sustainable, and eco-friendly material for metal sensing.

The force on dump truck body is telatively complicated, and different unloading working conditions will have effects on the body structure of dump truck. This paper made a modal analysis and feature buckling analysis of the body structure of dump truck under the unloading situation, and also made a nonlinear analysis under the certain circumstances. Through the ANSYS analysis, the body vibration frequency and buckling modal shape was calculated and figured out, and the design of dump truck body was optimized in order to make sure that the stiffness and stability meet the needs.

This paper presents a theoretical analysis of the recently reported observation of acoustic stop bands in two-dimensional scattering arrays (Robertson and Rudy, J. Acoust. Soc. Am. {\bf 104}, 694, 1998). A self-consistent wave scattering theory, incorporating all orders of multiple scattering, is used to obtain the wave transmission. The band structures for the regular arrays of cylinders are computed using the plane wave expansion method. The theoretical results compare favorably with the experimental data., 18 pages, 4 pages

In this Letter, we present a theoretical analysis of the acoustic transmission through two-dimensional arrays of straight rigid cylinders placed parallelly in the air. Both periodic and completely random arrangements of the cylinders are considered. The results for the sound attenuation through the periodic arrays are shown to be in a remarkable agreement with the reported experimental data. As the arrangement of the cylinders is randomized, the transmission is significantly reduced for a wider range of frequencies. For the periodic arrays, the acoustic band structures are computed by the plane-wave expansion method and are also shown to agree with previous results., 4 pages, 3 figures