<prompt> Yakha inguqulo eyinkimbinkimbi yalesi sigwebo Ama-foam ensimbi anezinhlayiya ezivaliwe athuthukisiwe kusukela cishe ngo-1956 nguJohn C. Elliott eBjorksten Research Laboratories.  <response>: Yiqiniso, inguqulo eyinkimbinkimbi yalesi sigwebo ithi Ama-Closed-cell metal foams athuthukisiwe kusukela cishe ngo - 1990, futhi ngokuvamile enziwa ngokufaka igesi noma i - foaming agent ensimbi encibilikisiwe. 