249 research outputs found
What is relevant in hyperthermia treatment: heat, temperature, field or something else?
There are intensive discussions in the scientific communities on the quality-parameters of hyperthermia. Most of the parties are convinced that only the temperature decides about the optimal
treatment, but strong doubts are also exists declaring the delivered heat (absorbed energy) or applied field (electro-magnetic influence) as primary effects. Strong points of the temperature-supporters
are the results of all the investigations which are concentrating on the temperature-dependence and the effectivity of Arrhenius analysis showing a phase transition at about 42.5 C, (this is the basic of
the step-down heating). On the other hand no doubts about the strong heat-dose dependence, which is most trivial by the treatment-time relevance in the clinical and laboratory results. The field
effects in the hyperthermia does not investigated so widely, but trivial questions arise to choose the techniques, different applicators, frequencies and couplings.
We had developed a set of the hyperthermia treatments applying various mixes of the heat and field effects. Four methods are applied successfully, where the heat- and field-effects are
involved by different ratio for various malignant cases. Among the four methods there are a method with only electric field application (ECT, percutane, no heat), moderate heat with moderate field
(PCT, cavitational), dominate local heat and electric field (EHY, loco-regional) and almost no field, only heat (WBH, whole-body application). The reached temperature in the tissue does not
determined only by the absorbed heat, physically other effects have decisional role in the measured temperature. The applied power in the various methods is very different, ranging from a few watts
to the few kW, while the electric field ranges from a few tens [mV/cell] to the few [nV/cell]. Due to the large and essential inhomogenities of the well-developed tumors only the average temperature
could be defined in most of the cases. Same average temperature is reachable by different applied power, only depending on the power-delivery conditions. This observation strongly supports the
importance of the heat (energy) absorption [W/kg] in the tumor instead of the only temperature conception.
Results show the excellence of the optimizing the method to the actual case. With all the four treatment modalities we have surprisingly good results by choosing the most optimal for the
given case and combining the applied methods with each other. Results by the different electro-hyperthermia applications will be shown in the presentation. The loco-regional applications are
massively applied in deep-organ treatments (pancreas, liver, brain, etc.), while the cavitational is devoted for prostate, bladder and gynecological, etc. cases. The percutane local treatment is very
effective for mammary-carcinomas, for head- and neck-cases, malignant melanomas, etc. The IR-A radiative whole-body hyperthermia is very useful in metastasizes, in systematic cases, etc.
According to the intensive laboratory and clinical experiences and strong evidences we can conclude, that beside the temperature the heat-delivery as well as the field effects are primary
important for the oncological hyperthermia
Rotation sets of billiards with one obstacle
We investigate the rotation sets of billiards on the -dimensional torus
with one small convex obstacle and in the square with one small convex
obstacle. In the first case the displacement function, whose averages we
consider, measures the change of the position of a point in the universal
covering of the torus (that is, in the Euclidean space), in the second case it
measures the rotation around the obstacle. A substantial part of the rotation
set has usual strong properties of rotation sets
MEASUREMENT OF YARN DIAMETER AND TWIST ANGLE WITH IMAGE PROCESSING SYSTEM
A special image processing system was developed by the Department of Polymer Engineer-
ing and Textile Technology TU Budapest and the KFKI Research Institute for Materials
Science Budapest supported by OTKA Fund of Hungary.
The system is suitable for measuring the diameter of fibres and yarns. The hardware
system based on a Projectina Projector Microscope and a CCD camera connected with
a image aquisition card. In addition to the testing of fibres and yarns the menu-driven
software frame provides also general image processing services and possibilities for special
statistical evaluations.
To demonstrate the applicability of the system some kinds of yarn were tested
An elementary proof of the irrationality of Tschakaloff series
We present a new proof of the irrationality of values of the series
in both qualitative and
quantitative forms. The proof is based on a hypergeometric construction of
rational approximations to .Comment: 5 pages, AMSTe
Sensitivity of VOF simulations of the liquid jet breakup to physical and numerical parameters
AbstractIn this paper the characteristics of the primary breakup of a liquid jet is analyzed numerically. We applied the Volumes of Fluids (VOF) approach utilizing the Direction Averaged Curvature (DAC) model, to estimate the interface curvature, and the Direction Averaged Normal (DAN) model, to propagate the interface. While being used for the first time to predict liquid atomization, this methodology showed a high accuracy. The influence of varying the fluid properties, namely liquid-gas density and viscosity ratio, and injection conditions is discussed related to the required grid resolution. Resulting droplet sizes are compared to distributions obtained through the One-Dimensional Turbulence (ODT) model
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