N-(diphenylphosphinoyl)hydroxylamine.

The title compound, C12H12NO2P, is the first structurally studied phospho­rus hydroxy­lamine derivative. The N atom is pyramidal. In the crystal structure, hydrogen bonds link mol­ecules into double ribbons

Thermal design of district-heating distribution networks

The behaviour of a double-pipe arrangement, consisting of a hot supply pipe and a warm return pipe enclosed within a relatively cold, rectangular, air-filled trench was considered. The minimum rates of steady-state heat losses occurred with the supply and the return pipes at displacement ratios Es = 0·45 and Er = -0·38 respectively; the hot pipe being in the upper region and the warm pipe vertically below it. The pipes were symmetrically placed with respect to the side walls. There is an optimal separation of 11·4 mm ± 1·1 mm for the gap between the supply and the return pipes for the temperature ranges and component sizes employed. This interesting result agrees quantitatively with those from previous experimental studies, but its significance had not been realised previously. By employing this optimal arrangement, a reduction in the total rate of heat loss from the supply pipe was obtained compared with that from this pipe placed anywhere else in the enclosure, but with similar temperatures for the pipes and trench walls as in the optimal arrangement.

tert-Butyl N-(phosphino­yloxy)carbamate.

The title compound, C17H20NO4P, contains pyramidal N atoms and adopts similar conformations in its three independent mol­ecules (A, B and C). Mol­ecules A and B form a dimer in the crystal structure by way of a pair of N-H...O hydrogen bonds, as does C with its inversion-generated partner

Potassium 4-nitrophenylsulfonate monohydrate.

The title compound, K+·C6H4NO5S-·H2O, forms a three-dimensional polymeric structure with an O8 coordination environment of the K+ cation

Unexpected Low Temperature Behaviour of Piroxicam Monohydrate

Upon cooling the monohydrate of the anti-inflammatory drug piroxicam shows reversible splitting (see picture). The cell also shows an irregular contraction over temperature and has a memory effect of its thermal history. This is due to strongly hydrogen bonded chains present in the monohydrate, which allow the crystal domains to contract separately from each other

Sustaining productivity of a Vertosol at Warra, Queensland, with fertilisers, no-tillage or legumes. 8. Effect of duration of lucerne ley on soil nitrogen and water, wheat yield and protein.

Soil nitrogen (N) supply in the Vertosols of southern Queensland, Australia has steadily declined as a result of long-term cereal cropping without N fertiliser application or rotations with legumes. Nitrogen-fixing legumes such as lucerne may enhance soil N supply and therefore could be used in lucerne-wheat rotations. However, lucerne leys in this subtropical environment can create a soil moisture deficit, which may persist for a number of seasons. Therefore, we evaluated the effect of varying the duration of a lucerne ley (for up to 4 years) on soil N increase, N supply to wheat, soil water changes, wheat yields and wheat protein on a fertility-depleted Vertosol in a field experiment between 1989 and 1996 at Warra (26degrees 47'S, 150degrees53'E), southern Queensland. The experiment consisted of a wheat-wheat rotation, and 8 treatments of lucerne leys starting in 1989 (phase 1) or 1990 (phase 2) for 1,2,3 or 4 years duration, followed by wheat cropping. Lucerne DM yield and N yield increased with increasing duration of lucerne leys. Soil N increased over time following 2 years of lucerne but there was no further significant increase after 3 or 4 years of lucerne ley. Soil nitrate concentrations increased significantly with all lucerne leys and moved progressively downward in the soil profile from 1992 to 1995. Soil water, especially at 0.9-1.2 m depth, remained significantly lower for the next 3 years after the termination of the 4 year lucerne ley than under continuous wheat. No significant increase in wheat yields was observed from 1992 to 1995, irrespective of the lucerne ley. However, wheat grain protein concentrations were significantly higher under lucerne-wheat than under wheat wheat rotations for 3-5 years. The lucerne yield and soil water and nitrate-N concentrations were satisfactorily simulated with the APSIM model. Although significant N accretion occurred in the soil following lucerne leys, in drier seasons, recharge of the drier soil profile following long duration lucerne occurred after 3 years. Consequently, 3- and 4-year lucerne-wheat rotations resulted in more variable wheat yields than wheat-wheat rotations in this region. The remaining challenge in using lucerne-wheat rotations is balancing the N accretion benefits with plant-available water deficits, which are most likely to occur in the highly variable rainfall conditions of this region