Origami and Kirigami Structure for Impact Energy Absorption: Its Application to Drone Guards.

As the use of drones grows, so too does the demand for physical protection against drone damage resulting from collisions and falls. In addition, as the flight environment becomes more complicated, a shock absorption system is required, in which the protective structure can be deformed based on the circumstances. Here, we present an origami- and kirigami-based structure that provides protection from various directions. This research adds a deformation capacity to existing fixed-shape guards; by using shape memory alloys, the diameter and height of the protective structure are controlled. We present three protective modes (1: large diameter/low height; 2: small diameter/large height; and 3: lotus shaped) that mitigate drone falls and side collisions. From the result of the drop impact test, mode 2 showed a 78.2% reduction in the maximum impact force at side impact. We incorporated kirigami patterns into the origami structures in order to investigate the aerodynamic effects of the hollow patterns. Airflow experiments yielded a macro understanding of flow-through behaviors on each kirigami pattern. In the wind speed experiment, the change in airflow velocity induced by the penetration of the kirigami pattern was measured, and in the force measurement experiment, the air force applied to the structure was determined.

Southern Nevada assisted living residents' perception of their oral health status and access to dental care.

OBJECTIVE: Oral health is an integral component of general health, and quality of life. The purpose of this study was to determine the perceptions of oral health status and acces\s to dental care by Southern Nevada Assisted Living Facilities Residents. METHODS: A cross-sectional questionnaire study design was used to survey residents between 34 and 99 years old residing in Assisted Living Facilities. Seventy respondents (42 males and 28 females) completed a survey that included personal oral hygiene, access to care, and demographic information. Data analyses included descriptive statistics and chi-square. RESULTS: Mean age was 75.78 years, and the majority had a college education (n = 41). Four currently smoked cigarettes. Twenty-nine (males = 14; females = 15) reported having dental insurance. Eleven respondents had seen a dentist twice a year, while 33 reported a visit less than 6 months. Forty-one reported the facility did not provide oral health care with majority (n = 64) indicating that accessing oral health care was difficult. Self-rated response to oral hygiene, a majority (n = 64) reported their oral hygiene as fair and five reported their oral hygiene as poor. CONCLUSIONS: Assisted living residents in Southern Nevada reported difficulty accessing dental services within and outside of the facility. Oral care models to address this unique population should be explored.

Preparation and characterization of electrospun silica nanofibers from PVP/P123 blended polymer solution.

Silica nanofibers were prepared by electrospinning method using PVP/P123 blend polymer solutions. Here, a triblock copolymer (Pluronic P123, EO20PO70EO20, M(av) = 5800) was used as the structure directing agent and polyvinyl pyrrolidone (PVP) as the fiber template. The samples were characterized by scanning electron microscopy (SEM), Fourier Transform Infrared (FT-IR), X-ray diffraction (XRD), TGA (thermal gravimetric analysis), and Brunauer-Emmett-Teller (BET). It was found that the silica nanofibers synthesized in this work had uniform pore structure with high surface area. An average fiber diameter, average pore diameter, and surface area were about 300 nm, 2.7 nm and 607 m2 g(-1). Adsorption equilibrium data of lysozyme on the synthesized silica nanofibers were correlated well with Langmuir equation.