656 research outputs found
Filterscape: energy recycling in a creative ecosystem
This paper extends previous work in evolutionary ecosystemic approaches to generative art. Filterscape, adopts the implicit fitness specification that is fundamental to this approach and explores the use of resource recycling as a means of generating coherent sonic diversity in a generative sound work. Filterscape agents consume and deposit energy that is manifest in the simulation as sound. Resource recycling is shown to support cooperative as well as competitive survival strategies. In the context of our simulation, these strategies are recognised by their characteristic audible signatures. The model provides a novel means to generate sonic diversity through de-centralised agent interactions
New island of cluster emitters
A new region of proton-rich parent nuclei decaying by spontaneous cluster emission with a measurable branching ratio relative to alpha decay is predicted within the analytical superasymmetric fission model. After a brief presentation of the model and of the seven mass tables used to calculate the released energy, the obtained results are discussed. Measurable half-lives and branching ratios are estimated for 12C, 16O, 28Si, and other cluster radioactivities of some nuclides having proton and neutron numbers in the range Z=56–64 and N=58–72. Such nuclei far from stability could be produced in reactions induced by radioactive beams
Two-dimensional nuclear inertia : analytical relationships
The components of the nuclear inertia tensor, functions of the separation distance R and of the radius of the light fragment R2, BRR(R,R2), BRR2(R,R2), and BR2R2(R,R2) are calculated within the Werner-Wheeler approximation, by using the parametrization of two intersected symmetric or asymmetric spheres. Analytical relationships are derived. When projected to a path R2=R2(R), the reduced mass is obtained at the touching point. The two one-dimensional parametrizations with R2=const, and the volume V2=const previously studied, are found to be particular cases of the present more general approach. Illustrations for the cold fission, cluster radioactivity, and α decay of 252Cf are given
Detection and Modeling of Radiation Induced Effects in Tissues by Dielectric Spectroscopy
The work presented here is applied physics research in the field of radiation treatment. We address the development of a new and innovative method, in vivo and possibly non-invasive, for tumor and healthy tissues control during and after the radiation treatment. The radiation treatment is delivered in an almost standardized manner for particular classes of tumors. The large variance in the individual radio sensitivity of healthy tissues and tumors often leads to local recurrence of neoplastic growth and/or distant metastatic disease which often remains untreated. The method is based on the measurement and analysis of electrical impedance data in the frequency domain from 50 mHz to 1MHz. The dielectric signature of the tissue carries information about the integrity of the plasma membrane, as well as about the tissue micro-architecture. We present dielectric models for biological materials and correlate their parameters with the subtle changes characterizing oncosis or apoptosis occurring as result of radiation or excision. Five tissue types (blood, kidney, liver, lung and heart) were studied and specific impedance models were created for each of them. Based on these models, analysis of freshly excised tissue and radiation-induced effects in excised tissue was carried out and model parameters extracted. The data we present shows correlation between known mechanisms of cellular death and the delivery of radiation, thus making possible a quantification of the individual response. Further work will be needed in order to correlate early impedance changes with late tissue changes characterizing the side effects of the radiotherapy
Potential energy surfaces for cluster emitting nuclei
Potential energy surfaces are calculated by using the most advanced
asymmetric two-center shell model allowing to obtain shell and pairing
corrections which are added to the Yukawa-plus-exponential model deformation
energy. Shell effects are of crucial importance for experimental observation of
spontaneous disintegration by heavy ion emission. Results for 222Ra, 232U,
236Pu and 242Cm illustrate the main ideas and show for the first time for a
cluster emitter a potential barrier obtained by using the
macroscopic-microscopic method.Comment: 10 pages, 21 figures, revtex
The quasi-molecular stage of ternary fission
We developed a three-center phenomenological model,able to explain qualitatively the recently obtained experimental results concerning the quasimolecular stage of a light-particle accompanied fission process. It was derived from the liquid drop model under the assumption that the aligned configuration, with the emitted particle between the light and heavy fragment, is reached by increasing continuously the separation distance, while the radii of the heavy fragment and of the light particle are kept constant. In such a way,a new minimum of a short-lived molecular state appears in the deformation energy at a separation distance very close to the touching point. This minimum allows the existence of a short-lived quasi-molecular state, decaying into the three final fragments.The influence of the shell effects is discussed. The half-lives of some quasimolecular states which could be formed in the Be and C accompanied fission of Cf are roughly estimated to be the order of 1 ns, and 1 ms, respectively
Flower colours through the lens: Quantitative measurement with visible and ultraviolet digital photography
Background: The study of the signal-receiver relationship between flowering plants and pollinators requires a capacity to accurately map both the spectral and spatial components of a signal in relation to the perceptual abilities of potential pollinators. Spectrophotometers can typically recover high resolution spectral data, but the spatial component is difficult to record simultaneously. A technique allowing for an accurate measurement of the spatial component in addition to the spectral factor of the signal is highly desirable
Neočekivana svojstva blizinskog potencijala
The cold fission barriers of heavy and superheavy nuclei (Z=80-120) are computed using two macroscopic models, the Yukawa-plus-exponential and the proximity potential. No shell and pairing corrections have been added. Unexpectedly, the barriers are showing two maxima in a wide region of nuclei (Z=96-120, mostly neutron-deficient ones) and various mass and charge asymmetries, lower for lighter nuclei and larger for heavier ones. The rather shallow minimum separating the maxima can reach a depth of 37 keV in the Yukawa-plus-exponential model and 190 keV in the proximity potential model.Fisijski bedemi teških i superteških jezgri (Z = 80 − 120) određeni su u dva makroskopska modela (Yukawa + eksponencijalni potencijal i blizinski potencijal) ne izračunavajući korekcije ljuske i sparivanje. U širokom području jezgri (Z = 96−120, uglavnom s manjkom neutrona), različitih masa i asimetrija naboja, bedemi imaju dva maksimuma, koji su niži za lakše jezgre a viši za teže jezgre. Plitki minimum izmedu maksimuma doseže dubinu 37 keV u Yukawa + eksponencijalnom modelu i 190 keV u modelu blizinskog potencijala
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