Organic Food and Agriculture - Ethics

Organic food is produced without the use of synthetic fertilizers and pesticides. Four further exclusions in organic production are: genetically modified organisms (GMOs), irradiation, prophylactic antibiotics, and engineered nanoparticles. These six exclusions differentiate organic agriculture from chemical agriculture. Agriculture and food harvesting and production date back millennia, and until about a century ago that history is de facto organic. The Industrial Revolution ushered in an era of novel production strategies. Agriculture was not immune to new views of industrialization and reductionism. Advances in chemistry enabled some implementation of such views. Early in the diffusion of chemical farming practices, the Austrian mystic Rudolf Steiner (1865–1924) called for a differentiated agriculture free of these new synthetic chemical inputs. The terminology, theory, and practices of biodynamic agriculture evolved (in the 1920s and 1930s) from Steiner’s Agriculture Course of 1924. It was a guided evolution, coordinated by Ehrenfried Pfeiffer (1899–1961) in Switzerland. The UK agriculturist, Lord Northbourne (1896–1982), invited Pfeiffer to lead a conference on biodynamics at his farm in Kent (in 1939). The following year Northbourne published his manifesto of organic farming, “Look to the Land.” In that book, he coined the term “organic farming” and wrote of a contest of “organic versus chemical farming”.The ideas and ideals of organic farming quickly proliferated internationally off the back of Northbourne’s 1940 book. Organic farming is now practiced in at least 179 countries, accounts for 50.9 million agricultural hectares, and a market value of US$ 81.6 billion (€75 billion)

Effects of ambient temperature and photoperiod on flowering time in faba bean (Vicia faba L.)

Flowering time is a vulnerable stage of plant development and is therefore a significant determinant of adaptation and grain yield in faba bean (Vicia faba L.). It is largely controlled by genotype, environmental factors of temperature and photoperiod, and genotype-by-environment interactions. The aim of this study was to evaluate variation in flowering time and the responses of flowering time to ambient temperature and photoperiod in Australian faba bean. Time of sowing experiments were carried out to assess variation among lines for flowering time (measured in days to flowering, thermal time to flowering and node of first flower) and to determine plant sensitivities to ambient temperature and photoperiod by regression analysis in the field, while four controlled environment experiments of differing temperature and photoperiod were undertaken to further analyse the variation in responses. Results showed significant variation in responses to both ambient temperature and photoperiod. Photoperiod was the main factor influencing variation in flowering time, with lines grouped as: sensitive, intermediate or insensitive. The responses to ambient temperature were more complex. Most lines fit the traditional linear model, but with possible variation in optimal temperature and/or vernalisation response, while some lines showed temperature insensitivity.Samuel C. Catt and Jeffrey G. Paul

Scramjet sidewall burning: Preliminary shock tunnel results

Experiments performed with a two dimensional model scramjet with particular emphasis on the effect of fuel injection from a wall are reported. Air low with a nominal Mach number of 3.5 and varied enthalpies was produced. It was found that neither hydrogen injection angle nor combustor divergence angle had any appreciable effect on thrust values while increased combustor length appeared to increase thrust levels. Specific impulse was observed to peak when hydrogen was injected at an equivalence ratio of about 2. Lowering the Mach number of the injected hydrogen at low equivalence ratios, less than 4, appeared to benefit specific impulse while hydrogen Mach number had little effect at higher equivalence ratios. When a 1:1 mixture by volume of nitrogen and oxygen is used instead of air as a test gas, it is found that hydrogen combustion is enhanced but only at high enthalpies

Further shock tunnel studies of scramjet phenomena

Scramjet phenomena were studied using the shock tunnel T3 at the Australian National University. Simple two dimensional models were used with a combination of wall and central injectors. Silane as an additive to hydrogen fuel was studied over a range of temperatures and pressures to evaluate its effect as an ignition aid. The film cooling effect of surface injected hydrogen was measured over a wide range of equivalence. Heat transfer measurements without injection were repeated to confirm previous indications of heating rates lower than simple flat plate predictions for laminar boundary layers in equilibrium flow. The previous results were reproduced and the discrepancies are discussed in terms of the model geometry and departures of the flow from equilibrium. In the thrust producing mode, attempts were made to increase specific impulse with wall injection. Some preliminary tests were also performed on shock induced ignition, to investigate the possibility in flight of injecting fuel upstream of the combustion chamber, where it could mix but not burn

Elimination of coherent noise in a coherent light imaging system

Optical imaging systems using coherent light introduce objectionable noise into the output image plane. Dust and bubbles on and in lenses cause most of the noise in the output image. This noise usually appears as bull's-eye diffraction patterns in the image. By rotating the lens about the optical axis these diffraction patterns can be essentially eliminated. The technique does not destroy the spatial coherence of the light and permits spatial filtering of the input plane

Midnight Fire-Alarm : Descriptive March-Galop

https://digitalcommons.library.umaine.edu/mmb-ps/2355/thumbnail.jp