Analytical and computer modelling of thermal processes of laser interaction with a single nanoparticle

RSC Advances ◽  
2014 ◽  
Vol 4 (99) ◽  
pp. 55760-55772 ◽  
Author(s):  
Victor K. Pustovalov ◽  
Andrei S. Smetannikov
Keyword(s):  
Laser Heating ◽  
Computer Modelling ◽  
Thermal Processes ◽  
Temporal Behavior ◽  
Laser Interaction ◽  
Medium Temperature ◽  
Single Nanoparticle

The problem of laser heating of NP is important for many applications in nanoscience. It is necessary to know the spatial–temporal behavior of the NP and medium temperature in this problem for analysis of experiments and prediction of new effects.

scholarly journals Optical modeling of a solar dish thermal concentrator based on square flat facets

2014 ◽  
Vol 18 (3) ◽  
pp. 989-998 ◽  
Author(s):  
Sasa Pavlovic ◽  
Velimir Stefanovic ◽  
Suad Suljkovic
Keyword(s):  
Ray Tracing ◽  
Focal Length ◽  
Performance Model ◽  
Thermal Processes ◽  
Medium Temperature ◽  
Optical Modeling ◽  
Radiative Power ◽  
Temperature Levels ◽  
Reflecting Surface ◽  
Optical Ray Tracing

Solar energy may be practically utilized directly through transformation into heat, electrical or chemical energy. We present a procedure to design a square facet concentrator for laboratory-scale research on medium-temperature thermal processes. The efficient conversion of solar radiation into heat at these temperature levels requires the use of concentrating solar collectors. Large concentrating dishes generally have a reflecting surface made up of a number of individual mirror panels (facets). Optical ray tracing is used to generate a system performance model. A square facet parabolic solar concentrator with realistic specularly surface and facet positioning accuracy will deliver up to 13.604 kW of radiative power over a 250 mm radius disk (receiver diameter) located in the focal plane on the focal length of 1500mmwith average concentrating ratio exceeding 1200. The Monte Carlo ray tracing method is used for analysis of the optical performance of the concentrator and to identify the set of geometric concentrator parameters that allow for flux characteristics suitable for medium and high-temperature applications.

Examination of thermal processes and structure formation in twin‐arc servicing of wagon wheels using computer modelling

2000 ◽  
Vol 14 (8) ◽  
pp. 642-647
Author(s):  
S N Kiselev ◽  
N N Voronin ◽  
G D Kuz'mina ◽  
E L Makarov ◽  
A A Kulikov
Keyword(s):  
Structure Formation ◽  
Computer Modelling ◽  
Thermal Processes

scholarly journals Thermal processes during local laser heating of biological tissues

2019 ◽  
Keyword(s):  
Mathematical Model ◽  
Laser Radiation ◽  
Time Constant ◽  
Biological Tissue ◽  
Laser Heating ◽  
Biological Tissues ◽  
Thermal Time ◽  
Thermal Processes ◽  
Thermal Time Constant ◽  
Continuous Power

Introduction. Lasers in medicine are currently widely used for both diagnosis and treatment. Studies of the thermal processes that occur when a person is exposed to laser radiation have made it possible to developinnovative methods of treating many diseases. Purpose: to study thermal processes in biological tissues during their local laser heating (mathematical model and experiment). Materials and methods. Using the developed mathematical model of the process of local heating of a certain region inside biological tissue, we studied the process of heating the environment by continuous and pulsed laser radiation using infrared light with a wavelength of 0.98 μm, red light with a wavelength of 0.65 μm, green light with a wavelength 0.5 microns and blue light with a wavelength of 0.435 microns. Results. The sizes of the heated region, the time of establishment and decrease in temperature are determined. The calculation results are in good agreement with the obtained experimental data. Findings. The mode of heating biological tissue with laser radiation depends on the wavelength. The maximum heating temperature of the irradiated section with a radiation pulse duration much shorter than the thermal time constant is independent of the shape and duration of the pulse and is determined only by the energy of the absorbed radiation. The distribution of heat into the medium during the duration of the pulse is determined by its duration and thermal diffusivity of the tissue. To reduce the heating of the surrounding tissue, it is necessary to use short radiation pulses. The progress of tissue heating by a sequence of radiation pulses depends on the relationship between the duration of the pulses, the period of their repetition, and the thermal time constant of the medium. The average (smoothed) temperature is the same as when heated with continuous power equal to the average power of the pulse-modulated radiation.

Research and Modelling on Electrical and Thermal Mode of LEDs Operation in the Luminaire

2018 ◽  
pp. 155-162 ◽  
Author(s):  
Sergei S. Kapitonov ◽  
Anastasia V. Kapitonova ◽  
Sergei Yu. Grigorovich ◽  
Sergei A. Medvedev ◽  
Taher Sobhy
Keyword(s):  
Thermal Conditions ◽  
Operating Mode ◽  
Thermal Processes ◽  
Thermal Mode ◽  
Crystal Temperature ◽  
Premature Failure ◽  
Model Based

In the article, the electrical and thermal processes in the LED lamp with varied parameters are investigated. Voltage and current measurements on all LEDs of the luminaire are carried out in the nominal operating mode. The power allocated to each LED is determined. The calculation of the LED crystal temperature was carried out using the developed thermal LED model based on the results of the measurements and by using “Multisim” program. It has been established that the temperature of the crystals of individual LEDs in the luminaire differ significantly, which leads to unfavourable thermal conditions for them and an increased likelihood of premature failure.

INFLUENCE OF HEAT TREATMENT OF MOUNTAIN MASSIVE ON TEMPERATURE MODE OF GEOTHERMAL CIRCULATION SYSTEM

2018 ◽  
pp. 44-50
Author(s):  
Yu. P. Morozov
Keyword(s):  
Heat Transfer ◽  
Operating Time ◽  
Fluid Motion ◽  
Coolant Temperature ◽  
Circulation System ◽  
Thermal Processes ◽  
Temperature Mode ◽  
Heat Influx ◽  
Stationary Heat Transfer

Based on the solution of the problem of non-stationary heat transfer during fluid motion in underground permeable layers, dependence was obtained to determine the operating time of the geothermal circulation system in the regime of constant and falling temperatures. It has been established that for a thickness of the layer H <4 m, the influence of heat influxes at = 0.99 and = 0.5 is practically the same, but for a thickness of the layer H> 5 m, the influence of heat inflows depends significantly on temperature. At a thickness of the permeable formation H> 20 m, the heat transfer at = 0.99 has virtually no effect on the thermal processes in the permeable formation, but at = 0.5 the heat influx, depending on the speed of movement, can be from 50 to 90%. Only at H> 50 m, the effect of heat influx significantly decreases and amounts, depending on the filtration rate, from 50 to 10%. The thermal effect of the rock mass with its thickness of more than 10 m, the distance between the discharge circuit and operation, as well as the speed of the coolant have almost no effect on the determination of the operating time of the GCS in constant temperature mode. During operation of the GCS at a dimensionless coolant temperature = 0.5, the velocity of the coolant is significant. With an increase in the speed of the coolant in two times, the error changes by 1.5 times.

Analysis and CAD modelling of a new geometric spiroid hob

2015 ◽  
Vol 6 (2) ◽  
pp. 89-93
Author(s):  
S. Bodzás ◽  
I. Dudás
Keyword(s):  
Computer Modelling ◽  
Cad Model ◽  
Axial Section ◽  
Cad Modelling ◽  
Definition Of

The objectives of this publication are the analysis of surfaces and edges of a new geometric spiroid hob with arched profile in axial section and the definition of their equations for computer modelling. On the basis of this we will work out the CAD model of hob for our further geometric calculations.

Sign in / Sign up

Export Citation Format

Share Document