No abstract available

[en] Methyl Bromide, CH₃Br, is the major organobromine species in the lower atmosphere and is a primary source of bromine in the stratosphere. It has a lifetime of 1.3 years. The IR methyl bromide spectra in the atmospheric window region, 7--13μ, was determined using a well tested Coriolis resonance and ell-doubling (and ell-resonance) computational system. A radiative forcing value of 0.00493 W/m²/ppbv was obtained for CH₃Br and is approximately linear in the background abundance. This value is about 2 percent of the forcing of CFC-11 and about 278 times the forcing of C0₂, on a per molecule basis. The radiative forcing calculation is used to estimate the global warming potential (GWP) of CH₃Br. The results give GWPs for CH₃Br of the order of 13 for an integration period of 20 years and 4 for an integration period of 100 years (assuming C0₂ = 1, following IPCC [1994]). While CH₃Br has a GWP which is approximately 25 percent of the GWP of CH₄, the current emission rates are too low to cause serious atmospheric greenhouse heating effects at this time

[en] The optical analyzer technique has proved to be a useful means of obtaining wave velocities at high pressures. Stepped wedges of the investigated material emit shock, and later, rarefaction waves into a transparent analyzer covering the material. The time interval between shock and rarefaction plotted versus wedge thickness gives a linear plot whose intercept fixes the target/driver thickness ratio for exact wave overtake, and thus gives a relation between the shock velocity and overtaking wave velocity at pressure. The slope of this line is intimately related to the wave velocity at pressure of the analyzer in front of the wedge. This aspect of the technique has not yet been exploited. We present the appropriate analysis, some data on bromoform (one of the analyzers used), and discuss some possible applications of this technique. copyright 1994 American Institute of Physics

[en] The technique of resonance enhanced multi-photon ionization (REMPI) of atomic and molecular species produced from a photofragmentation event combined with time-of flight (TOF) detection is used to examine scalar and vector properties following photodissociation. This technique is applied to the study of methyl bromide dissociation in a product state specific manner. We report measurements of the angular distributions and kinetic energy releases of the resulting bromine atoms in the ground and first spin-orbit excited state. Additionally we report measurements of the angular distributions and kinetic energy releases of the methyl fragment in the ground vibrational state, and also the excited state with one quanta in the ν₂ vibrational modes. These studies were carried out in the red wing of the absorption band at several wavelengths. For these measurements we were able to resolve the spin orbit state of the partner bromine fragment. From our observations we find new evidence for enhanced nonadiabatic curve crossing active in methyl bromide dissociation in comparison with earlier studies of methyl iodide. The atomic polarization produced following photodissociation of a diatomic molecule was investigated both theoretically and experimentally. We develop theoretical expressions relating the lab frame and molecular frame atomic polarization to the photoexcitation and subsequent dissociation of a diatomic molecule. This treatment includes both incoherent, coherent and non-adiabatic processes which may be active in the photodissociation process. We treat the general case of a polarized diatomic molecule yielding two fragments with non zero angular momentum. Experimentally, an investigation of the polarization of atomic Cl(²P_3/2) photofragments from the ∼330 nm photolysis of molecular chlorine using the REMPI-TOF technique is reported. We present a theoretical framework in which to treat such experiments allowing the extraction of parameters with direct physical significance to the coherent and incoherent pathways active in photodissociation. (author)

[en] Published in summary form only

[en] Plant quarantine, another termed legal control, is to contribute the safety and promotion of agriculture and forestry production and to protect natural environment by prescribing the necessary pertaining to the quarantine of import and export plants, and domestic plants and to control pest and diseases inflicting harms on plants. Methyl bromide as a fumigant is recognized as an important tool for the control of some pests and diseases, particularly quarantine pests of plants and plant-derived materials. Especially, methyl bromide is critical for preventing spread of plant pests that could have huge economic and/or environmental consequences. Methyl bromide is also a potent ozone-depleting gas. As a result of these disadvantage, ionzing radiation is rising an alternative eco-friendly method. Ionizing radiation for phytosanitary purpose uses predominantly in developing countries. In early 1995, the Hawaii Department of Agriculture was granted a special permit from USDA-APHIS allowing untreated Hawaiian fruits to be irradiated on the US mainland. In Arpil 1995, the first shipment of Hawaiian fruit was irradiated at a minimum quarantine dose of 0.25 kGy in an Isomedix plant near Chicago. Hawaii has become the first place in the world to use irradiation as a quarantine treatment of fruits. Since that, USDA-APHIS requested irradiation method for most import fruits to several countries including Mexico. Irradiation for phytosanitary purpose gradually increasing the use in different countries such as Australia, Tailand, and India. Now several countries such as India, Pakistan, and South Africa, prepared their own irradiation SOP for phytosanitary. It is urgent that the SOP is required in Korea because Methyl bromide is completely banned until 2018 worldwide. Therefore, we are trying to set up a irradiation quarantine SOP through current project until 2015.

[en] Solvents parities, which allows to lead a fully reaction of acetylene condensation are chosen. Reactionary ability of 1-piranyloxy-10-bromdecan is more than at 1-oxy-10 bromdecan is shown in this article

[en] The dissociative electron attachment to CH₃Br exhibits a remarkable dependence on the gas temperature. Low energy electrons (<1 eV) attach very weakly and dissociatively to CH₃Br at T=300 K but as T is increased to 700 K the electron attachment rate constant, k_a(ε,T) increases by more that 2 orders of magnitude; the thermal value of k_a is 1.08x10^-11 cm³s^-1 at 300 K and increases (by more than 300 times) to 3.28x10^-9 cm³s^-1 as T is raised to 700 K. The profound increases in k_a with small changes in the internal energy of CH₃Br (which may be induced also with infrared excitation) make this molecule a potential candidate for pulsed power switching applications

[en] Inorganic bromide residues and ¹⁴C-labelled methylated products (expressed as CH₃Br equivalent) in cocoa beans fumigated with [¹⁴C]-methyl bromide have been determined by radiometric and chemical methods. Determination of ¹⁴C by direct combustion in an oxygen chamber followed by liquid scintillation counting confirmed previous findings with respect to the magnitude, distribution and chemical nature of the residues. Although recovery of added bromide was good, the values of total bromide obtained by the chemical method were only half of those estimated from the total residual ¹⁴C-activity. This is attributed to loss of organic (presumably, protein-bound) bromide. In agreement with the total ¹⁴C-labelled residue contents, total bromide in shells was 20 times greater than that in nibs. The low levels of residues in the nib (12ppm as CH₃Br equivalent, 10ppm Br) and the further reduction of organic residues by roasting suggest that no toxicological and nutritional hazards may be expected from fumigation of cocoa beans with methyl bromide. (author)

No abstract available