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Self-healing materials with the ability to partially or completely restore their mechanical properties by healing the damage inflicted on them have great potential for applications where there is no or only limited access available to conduct a repair. Here, we demonstrate a bio-inspired new design for self-healing materials, where unit cells embedded in the structure are filled with a UV-curable resin and act as reservoirs for the self-healing agent. This design makes the repeated healing of mechanical damage possible. When a crack propagates and reaches one of these embedded reservoirs, the healing agent is released into the crack plane through the capillary action, and after polymerization through UV light exposure, bonds the crack faces. The structures here were fabricated using a stereolithography technique by a layer-by-layer deposition of the material. “Resin trapping” as a unique integration technique is developed for the first time to expand the capability of additive manufacturing technique for creating components with broader functionalities. The self-healing materials were manufactured in one step without any needs for any sequential stages, i.e. filling the reservoir with the healing agent, in contrast with the previously reported self-healing materials. Multiscale mechanical tests such as nanoindentation and three-point bending confirm the efficiency of our method.

Small U.S. businesses are underserved in terms of occupational health and safety (OHS) services. Little is known about organizational factors influencing OHS in these establishments. Machine guarding was quantitatively evaluated in 40 small businesses. Checklists were used to develop safety scores. Organizational information such as number of employees, unionization, and number of machines was obtained. Experience modification rates, annual sales, and credit ratings were also obtained. Safety scores were divided into terciles. Businesses with safety scores in the top third were unionized, had effective safety committees, and had been operational for more than 30 years. Interventions and policies targeted toward development and implementation of safety committees are needed to improve OHS in this cohort. Financial capability had no bearing on ability of a small business to mount an OHS programs. Non-unionized small businesses may be more vulnerable to occupational injuries.

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