Blast Shock Wave Mitigation Using the Hydraulic Energy Redirection and Release Technology

A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel

Tobacco and Cannabis Use During and After Pregnancy in California

ObjectivesAs the social and legal acceptance of cannabis use grows, health professionals must understand and mitigate the impact of cannabis use in the perinatal period. Here we compare the prevalence of tobacco and cannabis use during and after pregnancy in California, a state that recently legalized cannabis use.MethodsMeasures of tobacco and cannabis use during and after pregnancy were obtained from California's Maternal and Infant Health Assessment, an annual population-based survey of California resident women with a live birth. To allow analysis of county-level variation, we pooled data from the 35 counties with the largest numbers of births from 2017 to 2019.ResultsCannabis use was more than twice as common as cigarette smoking among pregnant women (4.9% vs. 2.1%) in California. This difference was even more pronounced in some counties; for example, in Los Angeles, cannabis use was four times more prevalent than cigarette use. Either during or soon after birth, 7.3% of women in California reported cannabis use. Of those who smoked tobacco cigarettes prior to pregnancy, 73% quit before their third trimester of pregnancy, though 33.0% of these women reported a post-partum relapse in cigarette use.ConclusionsStates that have legalized cannabis must attend to the increasing prevalence of perinatal cannabis use, as well as concurrent use with tobacco and other substances. Efforts to support cannabis cessation should draw from successful public health approaches in tobacco control

Current and future mobile and wearable device use by people with visual impairments

With the increasing popularity of mainstream wearable devices, it is critical to assess the accessibility implications of such technologies. For people with visual impairments, who do not always need the visual display of a mobile phone, alternative means of eyes-free wearable interaction are particularly appealing. To explore the potential impacts of such technology, we conducted two studies. The first was an online survey that included 114 participants with visual impairments and 101 sighted participants; we compare the two groups in terms of current device use. The second was an interview and design probe study with 10 participants with visual impairments. Our findings expand on past work to characterize a range of trends in smartphone use and accessibility issues therein. Participants with visual impairments also responded positively to two eyes-free wearable device scenarios: a wristband or ring and a glasses-based device. Discussions on projected use of these devices suggest that small, easily accessible, and discreet wearable input could positively impact the ability of people with visual impairments to access information on the go and to participate in certain social interactions. ACM Classification Keywords H.5.m. Information interfaces and presentation (e.g., HCI)