Effect of Matrix Properties on the Performance of a Counterflow Rotary Dehumidifier

1984 ◽  
Vol 106 (3) ◽  
pp. 638-645 ◽  
Author(s):  
J. J. Jurinak ◽  
J. W. Mitchell
Keyword(s):  
Finite Difference ◽  
Water Content ◽  
Sorption Isotherm ◽  
Moisture Diffusivity ◽  
Thermal Capacitance ◽  
Sorption Parameter ◽  
Heat Effects ◽  
Matrix Properties ◽  
The Matrix ◽  
Parameter Values

A finite difference model of a counterflow rotary dehumidifier is used to determine the effect of six matrix properties of dehumidifier performance. The matrix properties considered are the sorption isotherm shape, the maximum sorbent water content, the heat of sorption, the matrix thermal capacitance, matrix moisture diffusivity, and sorption isotherm hysteresis. The isotherm shapes and the sorption parameter values are selected to be representative of available insoluble desiccants. The results of the finite difference calculations show that the shape of the isotherm has a greater effect on dehumidification than the maximum water content. Large adsorption heat effects or matrix thermal capacitance has a detrimental impact on dehumidification. Hysteresis in the adsorption isotherm significantly impairs dehumidifier performance. The anlaysis shows that commercially available solid desiccants can result in nearly optimal dehumidifier performance.

scholarly journals Hexagonal-Shaped Spin Crossover Nanoparticles Studied by Ising-Like Model Solved by Local Mean Field Approximation

2021 ◽  
Vol 7 (5) ◽  
pp. 69
Author(s):  
Catherine Cazelles ◽  
Jorge Linares ◽  
Mamadou Ndiaye ◽  
Pierre-Richard Dahoo ◽  
Kamel Boukheddaden
Keyword(s):  
Spin Crossover ◽  
Hexagonal Lattice ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Ligand Field ◽  
Order And Disorder ◽  
The Matrix ◽  
Local Mean ◽  
Parameter Values

The properties of spin crossover (SCO) nanoparticles were studied for five 2D hexagonal lattice structures of increasing sizes embedded in a matrix, thus affecting the thermal properties of the SCO region. These effects were modeled using the Ising-like model in the framework of local mean field approximation (LMFA). The systematic combined effect of the different types of couplings, consisting of (i) bulk short- and long-range interactions and (ii) edge and corner interactions at the surface mediated by the matrix environment, were investigated by using parameter values typical of SCO complexes. Gradual two and three hysteretic transition curves from the LS to HS states were obtained. The results were interpreted in terms of the competition between the structure-dependent order and disorder temperatures (TO.D.) of internal coupling origin and the ligand field-dependent equilibrium temperatures (Teq) of external origin.

scholarly journals A new fourth-order explicit group method in the solution of two-dimensional fractional Rayleigh–Stokes problem for a heated generalized second-grade fluid

2020 ◽  
Vol 2020 (1) ◽  
Author(s):  
Muhammad Asim Khan ◽  
Norhashidah Hj. Mohd Ali ◽  
Nur Nadiah Abd Hamid
Keyword(s):  
Finite Difference ◽  
Stokes Problem ◽  
Stability And Convergence ◽  
Second Grade ◽  
Group Method ◽  
Two Dimensional ◽  
Second Grade Fluid ◽  
The Matrix ◽  
Grade Fluid ◽  
Generalized Second Grade Fluid

Abstract In this article, a new explicit group iterative scheme is developed for the solution of two-dimensional fractional Rayleigh–Stokes problem for a heated generalized second-grade fluid. The proposed scheme is based on the high-order compact Crank–Nicolson finite difference method. The resulting scheme consists of three-level finite difference approximations. The stability and convergence of the proposed method are studied using the matrix energy method. Finally, some numerical examples are provided to show the accuracy of the proposed method.

Effect of Laser Pre-Treatment on the Machining Performance of Aluminum/SiC MMC

2003 ◽  
Vol 125 (4) ◽  
pp. 378-384 ◽  
Author(s):  
Stuart Barnes ◽  
Richard Morgan ◽  
Andrew Skeen
Keyword(s):  
Tool Wear ◽  
Wear Mechanism ◽  
Laser Heating ◽  
Surface Damage ◽  
Edge Condition ◽  
Machining Performance ◽  
Matrix Properties ◽  
The Matrix ◽  
Pre Treatment ◽  
Measuring Tool

Although the abrasive reinforcement in MMCs primarily controls their machining behavior, the properties of the matrix also exert an influence. A 1200 W diode laser was used, due to the large footprint (5×0.3 mm) and the short wavelength (0.94 μm) to pre-treat a 2618 (18% SiC) alloy. The laser heating and self-quenching of the material modified the matrix properties. Machining performance was then assessed by measuring tool wear and edge condition, cutting forces, surface finish, and sub-surface damage. Results indicated that pre-treatment gave less wear, lower forces, and less sub-surface damage although abrasion remained the primary wear mechanism.

scholarly journals Application of microbial risk assessment on a residentially-operated Bio-toilet

2006 ◽  
Vol 4 (4) ◽  
pp. 479-486 ◽  
Author(s):  
Naoko Nakagawa ◽  
Hana Oe ◽  
Masahiro Otaki ◽  
Katsuyoshi Ishizaki
Keyword(s):  
Risk Assessment ◽  
Water Content ◽  
Risk Level ◽  
Microbial Risk Assessment ◽  
Microbial Risk ◽  
Infectious Risk ◽  
The Matrix ◽  
Pathogenic Viruses ◽  
Scale Experiment ◽  
Time Required

The Sustainable Sanitation System is a new wastewater treatment system that incorporates a non-flushing toilet (Bio-toilet) that converts excreta into a reusable resource (as fertilizer or humus for organic agriculture) and reduces the pollution load to environments of the rivers, the lakes, and the sea. However, the risk of exposure to pathogens should be considered, because excrement is stored in the Bio-toilet. The aim of the present work is to analyze the health risk of dealing with the matrix (excreta and urine mixed with sawdust) of the Bio-toilet. Therefore, the fate of pathogenic viruses was investigated using coliphages as a virus index, and the modeling of the die-off rate in matrix was introduced. Then the microbial risk assessment was applied to a Bio-toilet that was actually used in a residential house; the infection risks of rotavirus and enterovirus as reference pathogens were calculated. According to the lab-scale experiment using coliphages for investing the die-off rate of viruses in the Bio-toilet, Qβ had a higher die-off, which was greatly influenced by the water content and temperature. On the other hand, T4 showed a lower rate and was independent of water content. Therefore, these two phages' data were used as critical examples, such as viruses having high or low possibilities of remaining in the Bio-toilet during the risk assessment analysis. As the result of the risk assessment, the storage time required for an acceptable infectious risk level has wide variations in both rotavirus and enterovirus cases depending on the phage that was used. These were 0–260 days' and 0–160 days' difference, respectively.

scholarly journals Cyanate Ester Resin/Silica subnanocomposites and their superiority over nanocomposites due to fundamental role of constrained interfacial dynamics

2021 ◽  
Vol 2103 (1) ◽  
pp. 012100
Author(s):  
V A Bershtein ◽  
A M Fainleib ◽  
D A Kirilenko ◽  
P N Yakushev
Keyword(s):  
Positive Impact ◽  
Sol Gel ◽  
Cyanate Ester ◽  
Interfacial Dynamics ◽  
Cyanate Ester Resin ◽  
Sol Gel Process ◽  
Matrix Properties ◽  
Interfacial Areas ◽  
The Matrix

Abstract The study of nanostructure, thermal and relaxation properties (by HAADF-STEM, EDXS, DMA and DSC), combined with the calculations of interparticle distances and interfacial areas, has been performed for a series of the hybrid Cyanate Ester Resin (CER)/Si02 polymer composites with 0.01 to 10 wt.% Si02 units introduced via a sol-gel process. The absence of clusterization, arising only subnanometric Si02 nodes and their quasi-regular distribution within the amorphous matrix, with the shortest distances between nodes, provided their exceptional positive impact on the matrix properties at ultra-low Si02 contents of 0.03-0.1 wt.%. The superiority of these subnanocomposites over the nanocomposites was determined by the role of constrained interfacial dynamics over the whole matrix.

scholarly journals Approximation of a Complex Geometric Domain in Polar Coordinates

2019 ◽  
Vol 38 ◽  
pp. 105-118
Author(s):  
Gour Chandra Paul ◽  
Md Masum Murshed ◽  
Md Mamunur Rasid ◽  
Md Morshed Bin Shiraj
Keyword(s):  
Finite Difference ◽  
Coastal Region ◽  
Region Of Interest ◽  
Tangential Direction ◽  
Polar Coordinates ◽  
Computational Grids ◽  
The Matrix ◽  
Grid Points ◽  
Step Algorithm ◽  
Circular Grid

In this study, a complex geometric domain having a colour picture is approximated through a stair- step representation of the coastal and island boundaries to make it suitable for implementing finite difference method in solving shallow water equations (SWEs) in polar coordinates. As a complex domain, we choose the coastal region of Bangladesh situated at the northern tip of the Bay of Bengal (BOB). To cover the whole coastal region, the pole is selected at the point in the  plane assuming it on the mean sea level (MSL). Along the tangential direction, 265 uniformly distributive straight lines are considered through the pole and 959 circular grid lines centered at  are drawn towards the radial direction covering up to  latitude in the BOB. Firstly, a matrix with 960´265 computational grids is constructed from the colour information of the picture. By representing the grids with suitable notations, a proper stair-step algorithm is employed to the matrix obtained with the 960´265 grids to approximate the coastal and island boundaries to the nearest finite difference grid lines using an Arakawa C-grid system. The whole procedure is done with our developed MATLAB program. The grids representing the coastal stations are also identified closely in the obtained approximated domain. Such a type of presentation of the coastal geometry of the region of interest is found to incorporate its complexities properly with minimum computational grid points. GANIT J. Bangladesh Math. Soc.Vol. 38 (2018) 105-118

Thermal Behavior of Teeth During Restoration Procedure With Composite: Experimental Tests and Numerical Simulation

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
M. Potenza ◽  
P. Coppa ◽  
L. Cerroni ◽  
G. Bovesecchi
Keyword(s):  
Numerical Simulation ◽  
Finite Difference ◽  
Thermal Behavior ◽  
Heat Generation ◽  
Resin Composite ◽  
Experimental Tests ◽  
Cylindrical Sample ◽  
Temperature Trend ◽  
Thermal Capacitance ◽  
Hard Tissues

Abstract Different thermal mechanisms influence the tooth temperature during the reconstruction practice of tooth restoration: conduction in the hard tissues and their thermal capacitance, heat generation by composite curing, irradiation of the surface from the LED lamp, convection, and conduction to the environment. All these phenomena were considered into a numerical (finite difference, FD) model to simulate the temperature trend in a tooth during reconstruction with a resin composite addition, and results compared with experiments on cylindrical sample with a cavity filled with resin. Results demonstrate that all the phenomena have been sufficiently accurately described, and the way to apply the model to real teeth is recognized.

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