REDUCTION OF FAECAL MICROBIOLOGICAL INDICATORS IN DIFFERENT COMPOST TOILETS

Large variations in numbers of faecal indicator bacteria were found irrespective of the storage time of collected human faeces. Little heat seemed generated from composting processes when bin units were stored locally in households. The low reduction in microbiological parameters and very limited temperature increase were generally corroborated by the results obtained in experiment 2 when pathogen indicators were added to thoroughly mixed faecal matter. Even though Salmonella died of rapidly the other faecal bacterial indicators survived in large numbers. We conclude, that the collection and storage of human faeces in the closed plastic bins studied here is associated with only little temperature increase and subsequent reduction in faecal bacterial indicators and pathogens. Thus, the bin units do not seem especially suitable for composting and hygienisation of human faece

LATRINE COMPOSTING – A HYGIENIC EVALUATION

Thermophilic composting of faecal matter from urine diverting toilets can effectively reduce the numbers of faecal bacterial indicators and pathogen. Already at 50C, the numbers of pathogens, including the Salmonella phage, and indicator organisms analysed were effectively reduced within a few days of exposure. Although the numbers of enterococci were reduced, they were continuous isolated as purple colonies on Slanetz and Bartleys agar after prolonged exposure at all temperature levels studied. This indicates that certain micro-organisms present in the composted faecal material, Enterococcus spp. or micro-organisms resembling enterococci on the agar medium, can survive and multiply even at 60C. These findings question the use of enterococci as faecal indicators and test organisms to control the efficiency of composting of human faeces. Further work is in progress to identify the taxonomy of these organisms

OVERLEVELSE AF INDIKATORORGANISMER OG SMITSTOFFER I KOMPOSTTOILETTER OG VED SIMULERET CENTRALISERET EFTERKOMPOSTERING AF AFFØRING FRA MENNESKER

Som resultat af projekterne kan drages følgende hovedkonklusioner om kompostering af fæces fra mennesker: Fæces fra de undersøgte typer af kompostbeholdere bør ikke anvendes til jordbrugsformål uden viderebehandling, da dette skønnes at være behæftet med hygiejne- og sundhedsrisici. Det skyldes, at der ikke blev dokumenteret egentlige termofile temperaturstigninger i fæcesmaterialet i komposttoiletenhederne i Hjortshøj, Dyssekilde og Sverige, og at fækale indikatorbakteriers antal varierede voldsomt, og der ingen entydig tendens var til forekomst af lavere kimtal ved lange opbevaringstider af de opsamlede fækalier

Asymptotic statistics of the n-sided planar Voronoi cell: II. Heuristics

We develop a set of heuristic arguments to explain several results on planar Poisson-Voronoi tessellations that were derived earlier at the cost of considerable mathematical effort. The results concern Voronoi cells having a large number n of sides. The arguments start from an entropy balance applied to the arrangement of n neighbors around a central cell. It is followed by a simplified evaluation of the phase space integral for the probability p_n that an arbitrary cell be n-sided. The limitations of the arguments are indicated. As a new application we calculate the expected number of Gabriel (or full) neighbors of an n-sided cell in the large-n limit.Comment: 22 pages, 10 figure

Measuring the effective phonon density of states of a quantum dot

We employ detuning-dependent decay-rate measurements of a quantum dot in a photonic-crystal cavity to study the influence of phonon dephasing in a solid-state quantum-electrodynamics experiment. The experimental data agree with a microscopic non-Markovian model accounting for dephasing from longitudinal acoustic phonons, and identifies the reason for the hitherto unexplained difference between non-resonant cavity feeding in different nanocavities. From the comparison between experiment and theory we extract the effective phonon density of states experienced by the quantum dot. This quantity determines all phonon dephasing properties of the system and is found to be described well by a theory of bulk phonons.Comment: 5 pages, 3 figures, submitte

New Measure of the Dissipation Region in Collisionless Magnetic Reconnection

A new measure to identify a small-scale dissipation region in collisionless magnetic reconnection is proposed. The energy transfer from the electromagnetic field to plasmas in the electron's rest frame is formulated as a Lorentz-invariant scalar quantity. The measure is tested by two-dimensional particle-in-cell simulations in typical configurations: symmetric and asymmetric reconnection, with and without the guide field. The innermost region surrounding the reconnection site is accurately located in all cases. We further discuss implications for nonideal MHD dissipation

Multipolar Expansions for the Relativistic N-Body Problem in the Rest-Frame Instant Form

Dixon's multipoles for a system of N relativistic positive-energy scalar particles are evaluated in the rest-frame instant form of dynamics. The Wigner hyperplanes (intrinsic rest frame of the isolated system) turn out to be the natural framework for describing multipole kinematics. In particular, concepts like the {\it barycentric tensor of inertia} can be defined in special relativity only by means of the quadrupole moments of the isolated system.Comment: 46 pages, revtex fil