3,491 research outputs found

    Geoengineering and Non-Ideal Theory

    Get PDF
    The strongest arguments for the permissibility of geoengineering (also known as climate engineering) rely implicitly on non-ideal theory—roughly, the theory of justice as applied to situations of partial compliance with principles of ideal justice. In an ideally just world, such arguments acknowledge, humanity should not deploy geoengineering; but in our imperfect world, society may need to complement mitigation and adaptation with geoengineering to reduce injustices associated with anthropogenic climate change. We interpret research proponents’ arguments as an application of a particular branch of non-ideal theory known as “clinical theory.” Clinical theory aims to identify politically feasible institutions or policies that would address existing (or impending) injustice without violating certain kinds of moral permissibility constraints. We argue for three implications of clinical theory: First, conditional on falling costs and feasibility, clinical theory provides strong support for some geoengineering techniques that aim to remove carbon dioxide from the atmosphere. Second, if some kinds of carbon dioxide removal technologies are supported by clinical theory, then clinical theory further supports using those technologies to enable “overshoot” scenarios in which developing countries exceed the cumulative emissions caps that would apply in ideal circumstances. Third, because of tensions between political feasibility and moral permissibility, clinical theory provides only weak support for geoengineering techniques that aim to manage incoming solar radiation

    Coloured mulch as a weed control technology and yield booster for summer savory

    Get PDF
    An investigation into the effect of coloured mulch technology as a technique to control weeds when growing the essential oil plant, summer savory (Satureja hortensis) was made. As well as weed control, the effects on the production of crop biomass and essential oil content and quality were also considered. The mulch treatments produced significantly more biomass than either of the control treatments (which used no mulch either with or without herbicide). The white mulch treatment produced the greatest biomass, closely followed by the red mulch treatment. The blue mulch treatment was third in ranking, although not significantly greater than the black mulch. Estimates of the quantity of essential oil produced by each treatment followed a similar trend to that shown by biomass production

    Momentum Transfer to an Atom in a Molecule: Internal Excitation and Bond Dissociation

    Full text link
    An atom will dissociate from a compound if the atom receives a recoil momentum greater than some average value Q0. Considering a polyatomic molecule as composed of point‐mass atoms, there is derived an equation which relates Q0 to the bond energy, bond angles and distances, and masses of the atoms in the molecule. The minimum net recoil energy required for bond rupture, the kinetic energy of the recoiling radicals, and the internal energy of the radical originally bonded to the activated atom are calculated for a series of simple alkyl halides.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70523/2/JCPSA6-36-4-947-1.pd

    A model for liquid phase sintering

    Get PDF
    AbstractA quantitative model for liquid phase sintering is developed based on the following ideas. During heating a liquid phase forms, which is easily mobile, wets the solid particles completely, dissolves solid atoms and provides an easy diffusion path for them. The solid density increases by particle rearrangement and by the flattening of particle contacts. Driving (or retarding) forces result from capillary stresses, from applied mechanical stresses, from the pressure of gas entrapped in closed pores and from differences in chemical potential of the dissolved and precipitated matter. At higher densities the driving force may become very small, since the liquid pressure decreases and a negative contribution from the solid-liquid interface energy increases. At this stage grain coarsening plays an important role for the continued filling of larger and larger pores. The model is applied to describe nonisothermal densification curves measured on Si3N4 for various hold temperatures, axial stresses and green densities. Adjusting a moderate number of parameters all having a physical meaning leads to good agreement between theory and experiment