The effect of sublethal doses NaNO3 given in concentrates or by capsules on blood and vitamin A status of young red and white female cattle.

Administration of 0, 75, 150, 225 or 300 mg/kg body wt daily of NO3 as aqueous soln of NaNO3, mixed with the concentrate ration, to young heifers for a period of four months did not produce any serious toxic symptoms. In animals given 225 or 300 mg/kg there was, however, a slight reduction in feed consumption, along with increases in water intake, PCV values and conversion of Hb (up to 7%) into methaemoglobin. Respiration rate, body weight and vitamin A content of the liver were not affected. The toxicity of NaNO3 is discussed in relation to NO3 poisoning of cattle in the field. (Abstract retrieved from CAB Abstracts by CABI’s permission

The influence of different Ca and P supplies on the vitamin A, Cu and Mn status of young cattle with additional effects of growth and season.

Six 9-month-old female Dutch Friesian cattle were given hay and pelleted concentrates with added 130 g CaCO3 or 100 g Na2HPO4 daily for periods of 50 days each. The supplements did not significantly influence growth or vitamin A, Cu or Mn in liver or blood plasma, although more P tended to retard growth. Liver vitamin A, Cu and Mn generally decreased significantly with time. Cu was more closely related to growth than vitamin A or Mn. A fall of Cu in blood plasma and liver was associated with a fall in the vitamin A in liver and with an increase of vitamin A in plasma.-V. J. B. (Abstract retrieved from CAB Abstracts by CABI’s permission

A geometric construction of the exceptional Lie algebras F4 and E8

We present a geometric construction of the exceptional Lie algebras F4 and E8 starting from the round 8- and 15-spheres, respectively, inspired by the construction of the Killing superalgebra of a supersymmetric supergravity background. (There is no supergravity in the paper.)Comment: 12 page

Linear programming control of a group of heat pumps

For a new district in the Dutch city Meppel, a hybrid energy concept is developed based on bio-gas co-generation. The generated electricity is used to power domestic heat pumps which supply thermal energy for domestic hot water and space heating demand of households. In this paper, we investigate direct control of the heat pumps by the utility and how the large-scale optimization problem that is created can be reduced significantly. Two different linear programming control methods (global MILP and time scale MILP) are presented. The latter solves large-scale optimization problems in considerably less computational time. For simulation purposes, data of household thermal demand is obtained from prediction models developed for this research. The control methods are compared with a reference control method resembling PI on/off control of each heat pump. The reference control results in a dynamic electricity consumption with many peak loads on the network, which indicates a high level of simultaneous running heat pumps at those times. Both methods of mix integer linear programming (MILP) control of the heat pumps lead to a much improved, almost flat electricity consumption profile. Both optimization control methods are equally able to minimize the maximum peak consumption of electric power by the heat pumps, but the time scale MILP method requires much less computational effort. Future work is dedicated on further development of optimized control of the heat pumps and the central CHP

Upscaling a district heating system based on biogas cogeneration and heat pumps

The energy supply of the Meppel district Nieuwveense landen is based on biogas cogeneration, district heating, and ground source heat pumps. A centrally located combined heat and power engine (CHP) converts biogas from the municipal wastewater treatment facility into electricity for heat pumps and heat for district heating purposes. Development of the urban district is influenced by the current economic and building decline. For the district heating energy concept, a migration strategy for the required infrastructure is required. The migration spans the district’s small-scale starting phase involving 40 houses up to a scale of 176 houses. An optimization model which maximizes profitability is developed which includes data from district heating and cooling demand patterns. With the optimization model, optimal CHP size, boiler size, and operational hours are determined for various scenarios. From the scenario analysis, a migration strategy is developed which starts with a simple system concept supported by boilers to a larger system which includes a CHP. Sustainability in terms of CO2 emission savings of the energy concept is compared with other possible energy concepts