scholarly journals Thermal Radiation Absorption in Rectangular-Groove Cavities

1963 ◽  
Vol 30 (2) ◽  
pp. 237-244 ◽  
Author(s):  
E. M. Sparrow ◽  
V. K. Jonsson
Keyword(s):  
Thermal Radiation ◽  
Incident Energy ◽  
Radiation Absorption ◽  
External Radiation ◽  
Energy Distributions ◽  
Surface Conditions ◽  
Incoming Radiation ◽  
Wide Range ◽  
Cavity Opening ◽  
Rectangular Groove

The amount of energy absorbed when a stream of external radiation enters a rectangular-groove cavity has been calculated for a variety of surface conditions, cavity depths, and incident energy distributions. The surfaces of the cavity are either diffuse reflectors or specular reflectors, and a wide range of reflectivity values has been considered. The incoming radiation is either diffusely distributed across the cavity opening or else arrives in a bundle of parallel rays. The results show that for diffuse incoming radiation, a specular cavity absorbs more effectively than does a diffuse cavity. For incoming radiation in a parallel ray bundle, the comparison depends on the angle of inclination of the rays.

Radiation absorption, growth and yield of cereals

1978 ◽  
Vol 91 (1) ◽  
pp. 47-60 ◽  
Author(s):  
J. N. Gallagher ◽  
P. V. Biscoe
Keyword(s):  
Dry Matter ◽  
Growing Season ◽  
Growth Efficiency ◽  
Growth And Yield ◽  
Radiation Absorption ◽  
Exponential Equation ◽  
Crop Cover ◽  
Crop Growth Rate ◽  
Wide Range ◽  
Total Crop

SummaryAnalysis of measurements of absorbed radiation and leaf area indices of wheat and barley crops showed that throughout most of growth the fraction of absorbed solar radiation could be described by a simple exponential equation.For several of these crops grown under a wide range of weather and husbandry at Sutton Bonington and Rothamsted, 2-weekly values of crop growth rate (C) were closely related to radiation absorbed until ear emergence and about 3·0 g of dry matter (D.M.) were produced by each MJ of photosynthetically active radiation (PAR) absorbed. Final crop weight was closelyrelated to total PAR absorbed during growth (SA); on average about 2·2 g D.M. were produced per MJ absorbed, equivalent to a growth efficiency (Eg) of approximately 3·9%. Unfertilized and drought-stressed crops had a smaller Eg.The fraction of total crop D.M. harvested as grain (harvest index) varied more for wheat than for barley. Calculations of a maximum realizable grain yield made using the largest values of Eg and SA for the crops measured and assuming a harvestindex of 0.53 (achieved in an experimental crop) showed a grain D.M. yield of 10·3 t D.M./ha to be possible. To achieve such a yield would require full crop cover from the beginning of April until the end of July in a typical English growing season.

The Transient Temperature Distribution in a Slab Subject to Thermal Radiation

1965 ◽  
Vol 87 (1) ◽  
pp. 117-130 ◽  
Author(s):  
R. D. Zerkle ◽  
J. Edward Sunderland
Keyword(s):  
Temperature Distribution ◽  
Thermal Radiation ◽  
Radiant Heat ◽  
Analog Computer ◽  
Graphical Form ◽  
Transient Temperature ◽  
Transient Temperature Distribution ◽  
Temperature Distributions ◽  
Approximate Analytical Solutions ◽  
Wide Range

The transient, one-dimensional temperature distribution is determined for a slab, insulated on one face, and subjected to thermal radiation at the other face. The slab is initially at a uniform temperature and is assumed to be homogeneous, isotropic, and opaque; the physical properties are assumed to be independent of temperature. Transient temperature distributions for both heating and cooling situations are obtained by means of a thermal-electrical analog computer. A diode limiter circuit is used to simulate the nonlinear radiant heat flux. The transient temperature distributions are presented in a dimensionless, graphical form for a wide range of variables. Approximate analytical solutions are also given which complement and extend the solution charts over ranges of parameters not covered in the charts.

Biodegradation of Restorative Metallic Systems

1992 ◽  
Vol 6 (1) ◽  
pp. 32-37 ◽  
Author(s):  
Linda C. Lucas ◽  
Jack E. Lemons
Keyword(s):  
Metallic Materials ◽  
Multicomponent Alloys ◽  
Host Environment ◽  
Surface Conditions ◽  
Dental Restorations ◽  
Wide Range ◽  
Pure Metals ◽  
Metallic Systems

Metallic materials utilized for the construction of intra-oral and implant dental restorations include a wide range of relatively pure metals and multicomponent alloys. Basic corrosion and biodegradation properties of these alloys have been studied by both in vitro and in vivo techniques. These property characteristics have been shown to be dependent on composition and metallurgical state, combinations within a construct, surface conditions, mechanical aspects of function, and the local and systemic host environment. The susceptibility of these metallic materials to various forms of biodegradation will be presented, with emphasis on corrosion.

scholarly journals ISO Observations of AGN and Ultraluminous IR Galaxies

1998 ◽  
Vol 11 (2) ◽  
pp. 1131-1133 ◽  
Author(s):  
Alan F. M. Moorwood
Keyword(s):  
Ionization Potential ◽  
Elliptical Galaxy ◽  
Emission Lines ◽  
Spectral Energy ◽  
High Excitation ◽  
Low Resolution ◽  
Energy Distributions ◽  
Diagnostic Features ◽  
Wide Range ◽  
First Time

All the ISO instruments are contributing to the study of activity in galaxies of essentially all types. Although AGN's as such are pointlike, the beautiful CAM image of CenA shown by Catherine Cesarsky has given us the clearest view so far of its visually obscured nucleus and surrounding spiral disc embedded in an elliptical galaxy. The CAM CVF is also providing spectral images of the PAH features and important diagnostic ionic lines (e.g [NeII] and [NeIII]) in the circumnuclar regions of AGN and merging starburst systems (Vigroux et al., 1996). PHT is providing detailed spectral energy distributions over the complete 2.5-240µm range and PHTS is proving invaluable for assembling a catalogue of low resolution (R ⋍ 90) galaxy spectra covering the 6-12µm PAH features. SWS and LWS are generating higher resolution (R ⋍ 2000-200) spectra over the range 2.5-200µm such as that shown in Fig. 1. of the Circinus galaxy which exhibits both AGN and starburst activity and well illustrates the wide range of diagnostic features, many seen for the first time, accessible to ISO studies of galaxies. It shows the overall continuum with a peak around 100µm; PAH features and Si absorption which dominate the spectrum around 10µm; H recombination lines; H2 pure rotational emission lines; low ionization potential ionic lines excited by starburst activity and high excitation lines (up to ⋍ 300eV) excited by the visually obscured AGN.

A general consideration of incident impact energy accumulation in molecular dynamics thin film simulations—a new approach using thermal control layer marching algorithms

2005 ◽  
Vol 461 (2064) ◽  
pp. 3977-3998 ◽  
Author(s):  
Hong-Chang Lin ◽  
Jee-Gong Chang ◽  
Shin-Pon Ju ◽  
Chi-Chuan Hwang
Keyword(s):  
Thin Film ◽  
Layer Thickness ◽  
Reaction Layer ◽  
Incident Energy ◽  
Thermal Control ◽  
Computational Effort ◽  
Energy Accumulation ◽  
Wide Range ◽  
The Impact ◽  
Control Layer

This paper investigates several highly accurate algorithms which can be used to calculate the morphology in a wide range of thin film process simulations, and which require minimum computational effort. Three different algorithms are considered, namely the kinetic energy corrector (KEC) algorithm, the thermal control layer marching (TLM) algorithm, and the thermal control layer marching algorithm with an incorporated KEC function (TLMC). A common characteristic of these algorithms is that they all address the recovery of the impact incident energy within the free reaction layer. However, they differ in their treatment of the thermal control layer. The TLM and TLMC algorithms consider this layer to be moveable, whereas the KEC algorithm regards it as being fixed. The advantage of employing a moveable thermal control layer is that the computational effort required to carry out simulation is reduced since the atoms lying below this layer are excluded. The relative accuracy and efficiency of the proposed algorithms are evaluated by considering their use in the simulation of the trench-filling problem associated with the damascene process. The results of the present investigation indicate that the TLM algorithm has the ability to provide an accurate morphology calculation for low and medium energy incident atoms. However, for higher incident energy impacts, the TLMC algorithm is found to be a more appropriate choice because the incorporated energy corrector function is required to remove the higher energy accumulation which occurs within the deposited atoms. Furthermore, for all three algorithms, it is noted that a suitable specification of the free reaction layer thickness is essential in determining the accuracy and efficiency of the simulation. Finally, this paper discusses the relationship between the energy absorption rate and the thickness of the free reaction layer, and presents the optimal free reaction layer thickness for different incident energy intensities.

Enhanced Performance of Fabry–Perot Tunable Filter by Groove Geometry Design of Double Folded Cantilever

2020 ◽  
Vol 15 (6) ◽  
pp. 687-692
Author(s):  
Yifan Ding ◽  
Haigang Hou ◽  
Qingwei Huang ◽  
Junlin Liu ◽  
Shahid Hussain ◽  
...  
Keyword(s):  
Finite Element ◽  
Tunable Filter ◽  
Driving Voltage ◽  
Geometry Design ◽  
Element Simulation ◽  
Wide Range ◽  
Fabry Perot ◽  
Maximal Stress ◽  
Maximal Displacement ◽  
Rectangular Groove

Different grooves (v-shaped groove, trapezoidal groove and rectangular groove) are introduced into the traditional double-folded cantilever of Fabry–Perot Tunable Filter (FPTF) for the optical sensor. Using finite element simulation, the influence of groove geometry on the voltage–displacement relationship, stress distribution and reflector flatness of the FPTF are studied. The results show that the reflector supported by double folded cantilever with rectangular groove has a maximal displacement of 0.88 μm under 8 V driving voltage, which is 95% higher than double folded cantilever without groove. At 0.5 μm, the best flatness (warping angle of reflector) is only 0.0032° for reflector supported by double folded cantilever with rectangular groove, where the generated maximal stress in the double folded cantilever is 8.49 MPa. Compared with other double folded cantilevers with v-shaped groove, trapezoidal groove and without groove, the unique properties of double folded cantilever with rectangular groove are attributed to lower elastic modulus. The double folded cantilever with rectangular groove enlarges displacement results in wide range of bandpass wavelength of FPTF, and a best flatness to enhance the monochrome of bandpass wavelength.

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