No abstract

Slips occur when the friction demand of an individual exceeds the friction available from the shoe/floor interface. Shoe sole hardness is one of the factors thought to influence friction demand and available friction. The purpose of this study was to determine the influence of footwear sole hardness on the probability of slip initiation. Forty young adults were randomized into a hard or soft sole group. Slip events during the slippery floor trials were documented using a motion analysis system. The proportion of slip events in the hard sole group was greater than that in the soft sole group. The difference between utilized and available friction accurately predicted 90% of slip outcomes. Our data support the premise that individuals wearing shoes with harder soles are at greater risk for slipping. The results of this study suggest that shoe sole hardness should be considered when designing footwear aimed at decreasing slip risk.

A new phosphorus-containing polycyclic bismaleimide resin (BMPI) was prepared by the reaction of bis(3-maleimidophenyl) methylphosphine oxide (BAMP) with benzene-1,2,4,5-tetracarboxylic dianhydride (BTD) and maleic anhydride (MA). BMPI was confirmed by infrared (IR), 1 H-and 13 C-NMR spectroscopies. Its thermal properties were carried out by a differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) that revealed that the polymers have excellent thermal properties in the high temperature region and a high char yield of up to 53~65%. Furthermore, three conventional bismaleimide resins were prepared from different phosphorus-free bismaleimides for comparison, e.g. 4,4¢-bismaleimidodiphenylmethane (BDM), 4,4¢-bismaleimidodiphenylether (BDE), 4,4¢-bismaleimidodiphenylsulfone (BDS).

ABSTRACT:A novel polymer-dispersed liquid crystal composite film was prepared using liquid crystal and dual resins, namely, UV-curable urethane diacrylate and thermo-curable epoxy, with a fixed LC content of 50 wt%. A combination treatment of UV irradiation and heat was performed in sequential steps. At first, the urethane diacrylate resin was cross-linked through UV irradiation and a pre-UV-cured film was formed. Then, the pre-UV-cured film was heat treated for curing the thermo-curable epoxy resin. As the thermal polymerization continued, LC droplets were formed and became embedded POLYMER-DISPERSED LIQUID CRYSTAL COMPOSITE FILMSwithin the polymer matrix. PDLC films obtained from the polymer matrix with refractive indices in a range from 1.511 to 1.523 (1.517 ± 0.006) have optimal electro-optical properties. Films with a refractive index higher than 1.523 have high contrast ratio (CR), threshold voltage (V th ), and V 90 , whereas those with a low refractive index of 1.508 have low CR, V th , and V 90 . In this study, we found that PDLC composite films with optimal compositions prepared by dual resins (UV/thermal) have good electro-optical properties.

A new extraction method for ginsenosides from ginseng roots, ginseng leaves and ginseng drug preparations by Sep‐Pak C18 cartridges has been studied. Ginsenoside extraction by Sep‐Pak cartridges is a rapid, efficient, reproducible method. In addition, the extracts were analyzed by high performance thin layer chromatography (HPTLC) and reverse phase high performance liquid chromatography (HPLC). The major components of ginseng saponins were effectively separated using an ODS‐120T column.