scholarly journals Multistep Kinetic Behavior of the Thermal Decomposition of Granular Sodium Percarbonate: Hindrance Effect of the Outer Surface Layer

2015 ◽  
Vol 119 (38) ◽  
pp. 9749-9760 ◽  
Author(s):  
Takeshi Wada ◽  
Masayoshi Nakano ◽  
Nobuyoshi Koga
Keyword(s):  
Thermal Decomposition ◽  
Surface Layer ◽  
Outer Surface ◽  
Kinetic Behavior ◽  
Sodium Percarbonate

scholarly journals Thermodynamics and Kinetic Modeling of the ZnSO4.H2O Thermal Decomposition in the Presence of a Pd/Al2O3 Catalyst

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 548
Author(s):  
Gabriela V. T. Kurban ◽  
Artur S. C. Rego ◽  
Nathalli M. Mello ◽  
Eduardo A. Brocchi ◽  
Rogério C. S. Navarro ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Zinc Sulfate ◽  
Thermodynamic Assessment ◽  
Reaction System ◽  
Decomposition Temperature ◽  
Kinetic Behavior ◽  
Proposed Model ◽  
Al2o3 Catalyst ◽  
Iodine Reaction

The sulfur–iodine thermochemical water-splitting cycle is a promising route proposed for hydrogen production. The decomposition temperature remains a challenge in the process. Catalysts, such as Pd supported on Al2O3, are being considered to decrease reaction temperatures. However, little is known regarding the kinetic behavior of such systems. In this work, zinc sulfate thermal decomposition was studied through non-isothermal thermogravimetric analysis to understand the effect of a catalyst within the sulfur–iodine reaction system context. The findings of this analysis were also related to a thermodynamic assessment. It was observed that the presence of Pd/Al2O3 modified the reaction mechanism, possibly with some intermediate reactions that were suppressed or remarkably accelerated. The proposed model suggests that zinc sulfate transformation occurred in two sequential stages without the Pd-based material. Activation energy values of 238 and 368 kJ.mol−1 were calculated. In the presence of Pd/Al2O3, an activation energy value of 204 kJ.mol−1 was calculated, which is lower than observed previously.

scholarly journals DIFFERING RATES OF DEATH AT INNER AND OUTER SURFACES OF THE PROTOPLASM

1945 ◽  
Vol 28 (4) ◽  
pp. 343-347 ◽  
Author(s):  
W. J. V. Osterhout
Keyword(s):  
Surface Layer ◽  
Outer Surface ◽  
Diffusion Potential ◽  
Experimental Conditions ◽  
Toxic Agent ◽  
Inner Surface

The inner and outer protoplasmic surfaces in Nitella may differ greatly in behavior. When 0.01 M HgCl2 is applied externally death arrives first at the inner surface. But when 0.01 M HgCl2 + 0.01 M KCl is applied death takes place sooner at the outer surface. Since 0.01 M KCl by itself is not toxic its effect may be to condition the surface layer chemically or by means of the diffusion potential it sets up (this may amount to 100 mv.). These surfaces consist of non-aqueous films forming the boundaries of a layer of aqueous protoplasm not over 10 microns in thickness. These and earlier experiments with formaldehyde and with chloroform show clearly that it is possible to control the behavior of the protoplasmic surfaces so that when a toxic agent is applied it may produce death more rapidly at the inner or at the outer surface according to experimental conditions.

Effect of heat treatment on bonding performance of poplar via an insight into dynamic wettability and surface strength transition from outer to inner layers

Holzforschung ◽  
2020 ◽  
Vol 74 (8) ◽  
pp. 777-787 ◽  
Author(s):  
Demiao Chu ◽  
Jun Mu ◽  
Stavros Avramidis ◽  
Sohrab Rahimi ◽  
Zongyuan Lai ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Surface Layer ◽  
Outer Surface ◽  
Near Infrared ◽  
Sessile Drop ◽  
Treated Wood ◽  
Tangential Section ◽  
Surface Strength ◽  
Heat Treated ◽  
Bonding Failure

AbstractHeat treatment (HT) is thought to degrade wood surface wettability and cause gluing problems; this study focused on wettability and surface strength of the surface layer on heat-treated wood. The outer and inner surfaces formed by removing the 1-, 2- and 3-mm surface layers of heat-treated poplar on the tangential section were investigated. Dynamic wetting was analyzed according to the sessile drop method. The bonding failure models on different surfaces were also discussed based on both images of macro- and microscopic fracture interfaces. Using Fourier-transform near-infrared spectroscopy (FT-NIR), the cell wall chemistry on both outer and inner surfaces were analyzed. The results showed that the bonding strength of the outer surface was mainly affected by wettability, whereas the surface strength became the key factor for the inner layers. The removal of the first 1 mm of the surface layer enhanced the wetting process and transferred the failure mode from the glue line to the wood itself. FT-NIR revealed that the intensity of the thermal degradation on inner layers was alleviated with the removal depth; wettability and surface strength were enhanced compared with the outer surface. Surface abrasion and hardness declined, decreasing the surface strength and bonding capacity. This study indicates that the bonding of heat-treated wood is truly affected by the surface strength of the inner layers, in addition to the wettability on the outer surface.

The Demineralization of Human Dental Roots in the Presence of Fluoride

1987 ◽  
Vol 66 (8) ◽  
pp. 1370-1374 ◽  
Author(s):  
P.M.M. Hoppenbrouwers ◽  
F.C.M. Driessens ◽  
J.M.P.M. Borggreven
Keyword(s):  
Surface Layer ◽  
Outer Surface ◽  
Fluoride Concentration ◽  
Root Surface ◽  
Buffer Solution ◽  
Buffer Solutions ◽  
Ionic Product ◽  
Oral Environment ◽  
Root Surface Caries ◽  
Intact Roots

Intact roots of human molars, which had not been exposed to the oral environment, were exposed to buffer solutions of pH 5.5, which contained, besides calcium and phosphate, various concentrations offluoride. Densitometric measurements on contact-microradiograms of transverse sections of these roots produced data which were used to calculate the rate of demineralization ( Vdem). Vdem appeared to be reduced with increasing fluoride concentration and with decreasing pIOHA (i.e., the negative logarithm of the ionic product of hydroxyapatite) of the buffer solution. In addition, it was observed that, after some days of exposure, remineralization started to occur within the surface layer at some μm from the outer surface and that the region within which remineralization took place was extended inward with increasing time of exposure. These data suggest that fluoride is effective in the prevention of root surface caries. The mechanism of the interaction of fluoride with the root mineral is discussed.

Size-and phase-dependent structure of copper(ii) oxide nanoparticles

RSC Advances ◽  
2015 ◽  
Vol 5 (44) ◽  
pp. 35033-35041 ◽  
Author(s):  
Alauddin Ahmed ◽  
Paolo Elvati ◽  
Angela Violi
Keyword(s):  
Surface Layer ◽  
Outer Surface ◽  
Oxide Nanoparticles ◽  
Cuo Nanoparticle

Core (3 nm diameter) and outer surface layer (0.5 nm width) of a CuO nanoparticle of 4 nm in diameter.

Apparent kinetic behavior of the thermal decomposition of synthetic malachite

1999 ◽  
Vol 340-341 ◽  
pp. 387-394 ◽  
Author(s):  
Nobuyoshi Koga ◽  
Jose M Criado ◽  
Haruhiko Tanaka
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Behavior ◽  
Synthetic Malachite
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