scholarly journals Mechanochemical reactions of GaN-Al2O3 interface at the nanoasperity contact: Roles of crystallographic polarity and ambient humidity

Friction ◽  
2021 ◽  
Author(s):  
Jian Guo ◽  
Jian Gao ◽  
Chen Xiao ◽  
Lei Chen ◽  
Linmao Qian
Keyword(s):  
Underlying Mechanism ◽  
Water Molecules ◽  
Dangling Bond ◽  
Activation Energy Barrier ◽  
Surface Machining ◽  
Environmental Humidity ◽  
Relative Humidity Range ◽  
Ultra Precision ◽  
Humidity Range ◽  
Mechanochemical Reactions

AbstractMechanochemical reactions of the GaN-Al2O3 interface offer a novel principle for scientific and technological merits in the micro-/nano-scale ultra-precision surface machining. In this work, the mechanochemical reactions on Ga- and N-faced GaN surfaces rubbed by the Al2O3 nanoasperity as a function of the environmental humidity were investigated. Experimental results indicate that the N-face exhibits much stronger mechanochemical removal over the relative humidity range of 20%–80% than the Ga-face. Increasing water molecules in environmental conditions significantly promotes the interfacial mechanochemical reactions and hence accelerates the atomic attrition on N-face. The hypothesized mechanism of the selective water-involved mechanochemical removal is associated with the dangling bond configuration, which affects the mechanically-stimulated chemical reactions via altering the activation energy barrier to form the bonding bridge across the sliding interface. These findings can enrich the understanding of the underlying mechanism of mechanochemical reactions at GaN-Al2O3 interface and a broad cognition for regulating the mechanochemical reactions widely existing in scientific and engineering applications.

Sorption of water vapour by M-montmorillonite (M = Na, Li, La)

Clay Minerals ◽  
1990 ◽  
Vol 25 (4) ◽  
pp. 485-498 ◽  
Author(s):  
J. M. Trillo ◽  
J. Poyato ◽  
M. M. Tobías ◽  
M. A. Castro
Keyword(s):  
External Surface ◽  
Interlamellar Spacing ◽  
Molecular Water ◽  
Water Molecules ◽  
Sorbed Water ◽  
Octahedral Sites ◽  
Interlamellar Water ◽  
Relative Humidity Range ◽  
Humidity Range ◽  
Water Sorption Capacity

AbstractThe effect of heating on the water sorption capacity of a La-saturated montmorillonite, La-Mt, has been investigated. Sodium and Li as exchangeable ions have also been included for comparative purposes. XPS of La-Mt shows no migration of La(III) from interlamellar positions to octahedral sites on heating at 300°C. The water adsorbed as a multilayer on the external surface of the montmorillonite has been subtracted from the total sorbed water. Although the c-spacing of La-Mt corresponds to a two-layer hydrate, in the relative humidity range from 30 to 70%, the interlamellar water amounts to only 70% of the value for a complete monolayer. Heating at 300°C for 24 h has no influence on the uptake of molecular water between the structural layers of the La-Mt. The average numbers of water molecules per exchangeable ion sorbed into the interlamellar spacing up to 50% r.h. are: 5(Na-Mt), 3(Li-Mt) and 13(La-Mt).

scholarly journals Boltzmann-Based Empirical Model to Calculate Volume Loss during Spirit Ageing

Beverages ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 60
Author(s):  
Noemí del Toro del Toro ◽  
Fredy Fong Casas ◽  
Julio Ayan Rial ◽  
Maria Caridad Portuondo González ◽  
Harold Crespo Sariol ◽  
...  
Keyword(s):  
Boltzmann Equation ◽  
Relative Humidity ◽  
Quercus Alba ◽  
Volume Loss ◽  
Air Humidity ◽  
White Oak ◽  
The Boltzmann Equation ◽  
Relative Humidity Range ◽  
Two Parameters ◽  
Humidity Range

The Boltzmann equation is applied to fit data of volume loss for evaporation (in %) during spirit ageing in northern white oak (Quercus Alba) standard barrels of 205 L (+/− 10 L) using a temperature and humidity controlled cellar. The Boltzmann equation satisfactory fitted to the experimental data of the volume loss against temperature at constant humidity. Two parameters of the Boltzmann equation showed a linear dependency on the relative humidity of the air, while the other two parameters exhibited a constant value independently of the air humidity. The found empirical mathematical model can be used to calculate the volume loss for evaporation of spirits (40% v/v of ethanol) during ageing in terms of relative humidity (range: 40%–95%) and temperature (range: 10–30 °C) with significant accuracy.

Adsorption of water molecules on the surface of photo-catalyst: a first principles theoretical comparison between InVO4 and rutile TiO2

2002 ◽  
Vol 751 ◽  
Author(s):  
M. Oshikiri ◽  
M. Boero ◽  
J. Ye
Keyword(s):  
First Principles ◽  
Water Adsorption ◽  
Adsorption Process ◽  
Catalyst Surface ◽  
Chemical Reactivity ◽  
Water Molecules ◽  
Activation Energy Barrier ◽  
Reaction Proceeds ◽  
Adsorption Of Water ◽  
Dynamics Simulations

ABSTRACTThe adsorption process of water molecules on the surface of InVO4 has been investigated via first principles molecular dynamics simulations and compared with that of the well-known rutile TiO2. We have found that the surface of InVO4 shows a remarked chemical reactivity whenever comes in contact with water and H2O molecules are often adsorbed dissociatively on its surface. The reaction proceeds spontaneously in a way similar to the case of TiO2 and does not require the overcoming of an activation energy barrier. The peculiar atomic connectivity of the InVO4 bulk crystal structure and the changes at the catalyst surface induced by the water adsorption are discussed and compared with the TiO2 system.

Bioinspired stimuli-responsive multilayer film made of silk–titanate nanocomposites

2017 ◽  
Vol 5 (16) ◽  
pp. 3924-3931 ◽  
Author(s):  
Elena Colusso ◽  
Giovanni Perotto ◽  
Yu Wang ◽  
Marco Sturaro ◽  
Fiorenzo Omenetto ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Multilayer Structure ◽  
Multilayer Film ◽  
Stimuli Responsive ◽  
Term Stability ◽  
Long Term Stability ◽  
Relative Humidity Range ◽  
Responsive Behavior ◽  
Humidity Range

A bioinspired multilayer film made of a new silk–titanate nanocomposite material, showing a humidity-responsive behavior, has been fabricated. The multilayer structure mimics the structure of the cuticle of the Hoplia coerulea beetle and shows long-term stability over a very large relative humidity range.

Entomological Problems of Food Storage in Northern Nigeria

1952 ◽  
Vol 43 (1) ◽  
pp. 111-144 ◽  
Author(s):  
R. W. Howe
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Food Storage ◽  
Northern Nigeria ◽  
Diurnal Range ◽  
Relative Humidity Range ◽  
The Mean ◽  
Humidity Range

In Nigeria, shelled groundnuts are stored in sacks in covered warehouses and as pyramids in the open air. At the beginning of storage the nuts comprise approximately equal quantities of whole, split and broken nuts of a moisture content of 3·4 per cent. The sacks are exposed to direct hot sun whilst stacking.The mean monthly maximum shade temperature in Kano ranges from 101°F. in April to 85°F. in January and August and the mean monthly minimum from 75°F. in May to 56°F. in January. Monthly maximum relative humidities range from 100 per cent, in August and September to 45 per cent, in February, and the monthly minimum from 71 per cent, in August to 12 per cent, in February. The range of mean relative humidity is 81 per cent, in August and 18 per cent, in February. Rains fall between April and September, 70 per cent, falling in July and August. Heavy falls are recorded on about 25 days.Inside warehouses, the maximum monthly temperatures are 102°F. in May and 79°F. in January and February, and minimum temperatures are 81°F. in June, and 58°F. in February. In August the mean relative humidity range is 93 per cent, to 70 per cent. In December it is 34 per cent. to 20 per cent.Just under the roof of a warehouse and on the surface of pyramids the diurnal range is very large.

High relative humidity range sensor based on polymer-coated STW resonant device

2004 ◽  
Vol 100 (1-2) ◽  
pp. 126-130 ◽  
Author(s):  
P. Bruno ◽  
G. Cicala ◽  
F. Corsi ◽  
A. Dragone ◽  
A.M. Losacco
Keyword(s):  
Relative Humidity ◽  
High Relative Humidity ◽  
Range Sensor ◽  
Relative Humidity Range ◽  
Humidity Range

scholarly journals Effect of Relative Humidity on Mycelial Growth of Cercospora canescens

2021 ◽  
Vol 9 (3) ◽  
pp. 276-278
Author(s):  
Naresh Kumar ◽  
Keyword(s):  
Relative Humidity ◽  
Mycelial Growth ◽  
Mycelium Growth ◽  
Humidity Level ◽  
Mycelia Growth ◽  
Cent Relative Humidity ◽  
Relative Humidity Range ◽  
Humidity Range

The relative humidity studies revealed that maximum mycelial of fungus was observed at 90 per cent relative humidity (89.00 mm), which was followed by 100 per cent (86.30 mm). The least mycelia growth was observed at 50 per cent (45.30 mm). A significant decrease in mycelium growth was observed at 80, 70 and 60 per cent (80.40 mm, 70.20 mm and 57.00 mm) humidity level, respectively. Each fungus has its relative humidity range for the growth.

scholarly journals Highly sensitive, room temperature operated gold nanowire-based humidity sensor: adoptable for breath sensing

RSC Advances ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 1157-1164
Author(s):  
Parag V. Adhyapak ◽  
Aishwarya M. Kasabe ◽  
Amruta D. Bang ◽  
Jalindar Ambekar ◽  
Sulabha K. Kulkarni
Keyword(s):  
Relative Humidity ◽  
Room Temperature ◽  
Humidity Sensor ◽  
Gold Nanowire ◽  
Humidity Sensing ◽  
Highly Sensitive ◽  
Resistive Sensor ◽  
Relative Humidity Range ◽  
Humidity Range

A novel, highly sensitive gold nanowire (AuNW) resistive sensor is reported here for humidity sensing in the relative humidity range of 11% to 92% RH as well as for breath sensing.

scholarly journals Human Respiratory Monitoring Based on Schottky Resistance Humidity Sensors

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 430 ◽  
Author(s):  
Cunguang Lou ◽  
Kaixuan Hou ◽  
Weitong Zhu ◽  
Xin Wang ◽  
Xu Yang ◽  
...  
Keyword(s):  
Response Times ◽  
Silicon Nanowire ◽  
Humidity Resistance ◽  
Reduced Graphene ◽  
Recovery Times ◽  
Relative Humidity Range ◽  
Schottky Structure ◽  
Humidity Range ◽  
Breathing Monitoring ◽  
Humidity Monitoring

Two types of Schottky structure sensors (silicon nanowire (SiNW)/ZnO/reduced graphene oxide (rGO) and SiNW/TiO2/rGO) were designed, their humidity resistance characteristics were studied, and the sensors were applied to detect sleep apnea through breath humidity monitoring. The results show that the resistance of the sensors exhibited significant changes with increasing humidity, the response times of the two sensors within the relative humidity range of 23–97% were 49 s and 67 s, and the recovery times were 24 s and 43 s, respectively. Meanwhile, continuous breathing monitoring results indicate that the sensitivity of the sensors remained basically unchanged during 10 min of normal breathing and simulated apnea. The response of the sensor is still good after 30 days of use. We believe that the Schottky structure composite sensor is a very promising technology for human breathing monitoring.

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