Nuclear-weapons design and testing
China's nuclear arsenal has long been an enigma. It is a small force, based almost exclusively on land-based ballistic missiles, maintained at a low level of alert and married to a no-first-use doctrine – all choices that would seem to invite attack in a crisis. Chinese leaders, when they have spoken about nuclear weapons, have articulated ideas that sound odd to the Western ear. Mao Zedong's oft-quoted remark that ‘nuclear weapons are a paper tiger’ seems to be bluster or madness. China's nuclear forces are now too important to remain a mystery. Yet Westerners continue to disagree about basic factual information concerning one of the world's most important nuclear-weapons states. This Adelphi book documents and explains the evolution of China's nuclear forces in terms of historical, bureaucratic and ideological factors. There is a strategic logic at work, but that logic is mediated through politics, bureaucracy and ideology. The simplest explanation is that Chinese leaders, taken as a whole, have tended to place relatively little emphasis on the sort of technical details that dominated US discussions regarding deterrence. Such profound differences in thinking about nuclear weapons could lead to catastrophic misunderstanding in the event of a military crisis between Beijing and Washington.
The radioactive signature of the hydrogen bomb
It has long been supposed that the Teller‐Ulam invention of February 1951, that made the construction of a full‐scale fusion device feasible could be deduced from a careful analysis of the debris that scatters worldwide after an atmospheric test. This was part of the theme of an article in the January/February 1990 issue of the Bulletin of Atomic Scientists written by Daniel Hirsch and William G. Mathews.1 Their conclusion, arrived at to a large degree through interviews with Hans Bethe, was that the H‐bomb secret was given to the Soviets, not through the spy Klaus Fuchs, but rather by carrying out Mike, the first test of a fusion device based on the Teller‐Ulam ideas. The Bulletin article and an extended version of that paper issued by the Los Angeles based Committee to Bridge the Gap2 argue that the observation of the very high neutron fluencies in the explosion, which can be derived from the fallout composition, would lead a competent scientist to the trick. In the present paper it is proposed that thi...
Soil organic matter and microbiological development of technosols in the South Wales Coalfield
Abstract Degraded land (formerly ‘reclaimed’) after surface-coal-mining is a serious problem in South Wales. This project uses forestation to foster soil development on opencast coal-mine spoil technosols. It compares records of humification and the soil microbiological system (microcoenosis) using paired data from the same plantings in 1998 and 2018. Statistical analysis finds no significant difference between samples collected under trees planted by the pit-planting versus trench planting method or trees planted using organic or mineral fertilizer. However, there are strong significant differences in both soil organic matter and microflora components and significant correlations with time since tree planting. Most components of the soil organic carbon (TOC) and the microflora increase, often significantly. However, compared to 2018, 1998 samples contain significantly greater maximum levels of Insoluble Carbon while the microflora had significantly more Ammonifying bacteria. Decreases in Insoluble Carbon explain the relatively small increase in TOC between 1998 and 2018. The % extracted with 0.1 N H2SO4 is significantly larger in 2018, suggesting active weathering. Similarly, both the maxima and minima of total Humic and Fulvic acids content, extracted with 0.1 M Na4P2O7 + 0.1 M NaOH, are significantly greater in 2018. Total microflora shows significant positive correlations with time-since-tree-planting as do the proportions of bacilli and actinomycetes but the correlation with ammonifying bacteria is negative. In 1998, the microflora was dominated by non-spore-forming bacteria while, in 2018, bacilli and actinomycetes prevail; both are involved in the transformation of complex organic compounds and humification. This indicates active transformation of more complex organic compounds and advancing humification. In sum, forestation of these degraded, formerly reclaimed, opencast coal-mine spoils has resulted in a massive increase in both the size and functioning of the soil organic system.