KRL began producing highly enriched uranium (HEU) as well as developing the krytron, while classified work on the uranium weapon design took place with uranium hexafluoride (UF6) being reduced to uranium metal and machined into weapon pits. The KRL began publishing a series of academic articles on numerics and computational methods for centrifuge design, including a 1987 article co-authored by Abdul Qadeer Khan on techniques for balancing sophisticated ultracentrifuge rotors. In the 1990s, KRL had a number of the most high-performance supercomputer and parallel computing systems installed at the facility. A parallel Computational Fluid Dynamics (CFD) division was established which specialized in conducting high performance computations on shock waves in weapons effect from the outer surface to the inner core by using difficult differential equations of the state of the materials used in the bomb under high pressure. In an investigative report published by Nuclear Threat Initiative (NTI), Chinese scientists were reportedly present at Kahuta in the early 1980s— an unconfirmed indicator of Chinese assistance in the development of equipment at Kahuta. In 1996, the U.S. intelligence community maintained that China provided magnetic rings for special suspension bearings mounted at the top of rotating centrifuge cylinders. In 2005, it was revealed that President Zia-ul-Haq's military government had KRL run a HEU programme in the Chinese nuclear weapons program. Abdul Qadeer Khan also alleged that "KRL has built a centrifuge facility for China in Hanzhong city". Extended research The academic research programs and development opportunities at the KRL are supported by the physics departments of the Government College University in Lahore in Punjab and the University of Karachi in Sindh. The KRL supports its physics program through funding and providing scholarship to physics and engineering students at the Government College University. The continuing efforts to make the laboratories more science efficient led the Ministry of Science (MoST) to grant a three research and fellowship programmes with the Government College University with the support of Pakistan Science Foundation (PSF). Since 1980 at present, the KRL continues to develop the research work on computational mathematics, supercomputing and advanced mathematics to the extended applications to natural sciences. In 1999, the KRL established a research institute on computer science at Kahuta, which was later integrated to University of Engineering and Technology in Taxila. The civilian research on biotechnology, biology and Genetic Engineering is supported by the KRL at the University of Karachi, with the support