HAX, the hardware accelerator run by SOSV, is hosting its first demo day in four years on May 1st. The event will showcase over 30 startups working on a variety of challenges, including climate change, manufacturing, computing, health, and energy. Some of the notable companies participating in the demo day include CocoonCarbon, which has developed a small factory inside a shipping container that can turn steel runoff into sustainable cement; PureLi, which has designed a system to dramatically speed up lithium extraction in brine lakes; Renovate Robotics, which has produced a winch-based robot that installs roof shingles; and Silana, which is working on a robotic system that can completely automate the sewing process. The full list of companies participating in the demo day can be found below.