scholarly journals Performance of Flexible Chemoresistive Gas Sensors after Having Undergone Automated Bending Tests

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5190 ◽  
Author(s):  
Miriam Alvarado ◽  
Silvia De La Flor ◽  
Eduard Llobet ◽  
Alfonso Romero ◽  
José Luis Ramírez
Keyword(s):  
Metal Oxide ◽  
Gas Sensing ◽  
Flexible Substrate ◽  
Test Procedure ◽  
Chemical Vapor ◽  
Bending Test ◽  
Bending Tests ◽  
Ag Electrodes ◽  
Different Types ◽  
Before And After

Many sensors are developed over flexible substrates to be used as wearables, which does not guarantee that they will actually withstand being bent. This work evaluates the gas sensing performance of metal oxide devices of three different types, before and after having undergone automated, repetitive bending tests. These tests were aimed at demonstrating that the fabricated sensors were actually flexible, which cannot be taken for granted beforehand. The active layer in these sensors consisted of WO3 nanowires (NWs) grown directly over a Kapton foil by means of the aerosol-assisted chemical vapor deposition. Their response to different H2 concentrations was measured at first. Then, they were cyclically bent, and finally, their response to H2 was measured again. Sensors based on pristine WO3-NWs over Ag electrodes and on Pd-decorated NWs over Au electrodes maintained their performance after having been bent. Ag electrodes covered with Pd-decorated NWs became fragile and lost their usefulness. To summarize, two different types of truly flexible metal oxide gas sensor were fabricated, whereas a third one was not flexible, despite being grown over a flexible substrate following the same method. Finally, we recommend that one standard bending test procedure should be established to clearly determine the flexibility of a sensor considering its intended application.

scholarly journals The reasons and adverse effect of internal diesel injector deposits formation

2014 ◽  
Vol 156 (1) ◽  
pp. 20-29
Author(s):  
Zbigniew STĘPIEŃ
Keyword(s):  
Adverse Effect ◽  
Test Procedure ◽  
Formation Mechanisms ◽  
Engine Test ◽  
Paper Report ◽  
Diesel Injection ◽  
Different Types ◽  
Before And After ◽  
Long Time ◽  
State Of Affairs

The paper report on the state of affairs so far in the scope of internal diesel injection deposits (IDID) issue affecting modern diesel high pressure common rail (HPCR) systems. Different types of deposits have been described and the factors supporting their creation. These deposits have been extensively studied to understand their formation mechanisms and composition. To this end an engine test procedure was developed to assess the deposit forming tendencies of various types. Findings of two long time dynamometer engine tests in which the course of the IDID formation and HPCR performance impairing was followed by measurement different engine parameters have been reported. Performance evaluation of HPCR injectors before and after tests have been presented also.

Characterization of Germanium Nanowires-Flexible Substrate Assemblies Integrated via Direct Synthesis Methods

2010 ◽  
Author(s):  
Justin Rodgers ◽  
Julia Edel ◽  
Johan Rivera ◽  
Ongi Englander
Keyword(s):  
Crack Formation ◽  
Flexible Substrate ◽  
Direct Synthesis ◽  
Chemical Vapor ◽  
Synthesis Methods ◽  
Bending Tests ◽  
Germanium Nanowires ◽  
Reduced Temperature ◽  
Deposition Techniques

Nanowires are successfully synthesized directly on two types of flexible substrates, Kapton and silicone, to yield integrated compliant assemblies. Reduced temperature catalyst-assisted chemical vapor deposition techniques enable the direct integration processes. The mechanical properties of these assemblies are evaluated using bending tests where tensile or compressive strains are applied to the samples. Crack formation in the form of channeling or debonding, typical of thin films on substrates, is observed. The allowable strain prior to mechanical failure is assessed.

Effect of Direct Electric Resistance Heat Treatment on Mechanical Properties of NiTi Orthodontic Arch Wires

2008 ◽  
Vol 55-57 ◽  
pp. 249-252 ◽  
Author(s):  
W. Kiattiwongse ◽  
Anak Khantachawana ◽  
P. Santiwong
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Bending Test ◽  
Electric Resistance ◽  
Bending Tests ◽  
Three Point Bending ◽  
Heat Treated ◽  
Different Types ◽  
Orthodontic Archwires ◽  
A Current

Two types of rectangular orthodontic archwires; NiTiTM and 40oCuNiTi, were heat treated by Direct Electric Resistance Heat Treatment (DERHT) using different electric currents for 4 s. Their mechanical properties were then evaluated by micro hardness and three-point bending tests. After applying 4.5-5.5 A current, the hardness of NiTiTM increased with the increased current, whereas the change in hardness of 40oCuNiTi was slight. When 6 A current was applied, the hardness of the midspan of both wires significantly decreased. From the three-point bending test, unloading forces of NiTiTM increased after treating with 5.5 A current, while those of 40oCuNiTi decreased. However, both specimens lost their superelasticity when applied with 6 A current. In conclusion, after DERHT, various changes in mechanical properties can be noted in the different types of nickel titanium archwire.

Effect of Dry-Wet Circulation and Temperature Change on Properties of Polyurea Coatings

2010 ◽  
Vol 150-151 ◽  
pp. 1203-1208 ◽  
Author(s):  
Ping Lv ◽  
Xin Mao Li ◽  
Wei Bo Huang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Temperature Change ◽  
Bending Test ◽  
Curing Time ◽  
Bending Tests ◽  
Temperature Changes ◽  
Before And After ◽  
Alternating Temperature ◽  
Changing Rate

This paper mainly studies the mechanical properties and microstructure of polyurea coatings (SPUA) through the experiment of dry-wet circulation. The influence of different curing time of SPUA coating before and after the dry cycle of the mechanical properties and surface morphology changes were researched. Use the alternating temperature and low bending tests to research,the variation of temperature changes to the SPUA of different curing time. The result of the dry-wet circulation experiment shows that the tensile strength of cured 1d, 3d and 7d SPUA coating after 30d dry-wet circulation increased 9.6%、19.2% and 44.7% respectively, the tear strength increased 3.2%、5.6% and 47.3% respectively. The microstructure research shows the 7d cured SPUA coating after 30 times dry-wet circulation will reduce the holes and narrow the hole diameter in a certain degree. The temperature change experimental results show that during -20 ～50 alternating temperature process, the tensile strength of the coating appears to increase, 3d and 7d cured SPUA coating after 40d temperature alternating tensile strength changing rate is -14.2% and 9.8% respectively. Low-temperature bending test shows that the SPUA coating will not appear any cracks cracking phenomena after placed the coating in （-20+2 ）for 168h.

SPRING-BACK CHARACTERISTICS OF GRAIN-REFINED MAGNESIUM ALLOY ZK60 SHEET

2008 ◽  
Vol 22 (31n32) ◽  
pp. 6076-6081 ◽  
Author(s):  
SEONG-HOON KANG ◽  
YOUNG-SEON LEE ◽  
JUNG-HWAN LEE
Keyword(s):  
Grain Size ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Testing Temperature ◽  
The Other ◽  
Bending Test ◽  
Spring Back ◽  
Bending Tests ◽  
Grain Sizes ◽  
Before And After

In this work, the effect of grain size on the spring-back characteristic was investigated by carrying out air-bending test using magnesium alloy ZK60 sheet with thickness of 0.5 mm at the various temperatures from room temperature to 300 °C. The angles of the bent specimen before and after unloading were measured in order to quantify spring-back amount. It was found out from the bending tests that when the specimens with grain sizes of 14.66 and 60.71 µm were bent by 90°, the amount of spring-back was relatively small at the testing temperature range and was in the range between -2.5° and 2.5°. On the other hand, the spring-back amount dramatically increased at room temperature and phenomenon of spring-go was observed at high temperature when the specimen with submicro grain size of 0.98 µm was bent by 90°. From this finding, it was confirmed that the different spring-back characteristics according to the grain size takes place and thus the grain size of material is one of the important factors which have an effect on the spring-back.

Metal-oxide based ammonia gas sensors: A review

2020 ◽  
Vol 10 ◽  
Author(s):  
Priya Gupta ◽  
Savita Maurya ◽  
Narendra Kumar Pandey ◽  
Vernica Verma
Keyword(s):  
Metal Oxide ◽  
Metal Oxides ◽  
Gas Sensor ◽  
Gas Sensors ◽  
Review Paper ◽  
Gas Sensing ◽  
Gas Sensitivity ◽  
Ammonia Gas ◽  
Ammonia Sensing ◽  
Ammonia Gas Sensors

: This review paper encompasses a study of metal-oxide and their composite based gas sensors used for the detection of ammonia (NH3) gas. Metal-oxide has come into view as an encouraging choice in the gas sensor industry. This review paper focuses on the ammonia sensing principle of the metal oxides. It also includes various approaches adopted for increasing the gas sensitivity of metal-oxide sensors. Increasing the sensitivity of the ammonia gas sensor includes size effects and doping by metal or other metal oxides which will change the microstructure and morphology of the metal oxides. Different parameters that affect the performances like sensitivity, stability, and selectivity of gas sensors are discussed in this paper. Performances of the most operated metal oxides with strengths and limitations in ammonia gas sensing application are reviewed. The challenges for the development of high sensitive and selective ammonia gas sensor are also discussed.

scholarly journals Quality assessment of gas produced from different types of biomass pellets in gasification process

2019 ◽  
Vol 38 (2) ◽  
pp. 406-416 ◽  
Author(s):  
Marcel Mikeska ◽  
Jan Najser ◽  
Václav Peer ◽  
Jaroslav Frantík ◽  
Jan Kielar
Keyword(s):  
Gas Turbines ◽  
Combustion Engine ◽  
Calorific Value ◽  
Internal Combustion ◽  
Combustion Gas ◽  
Gas Cleaning ◽  
Gasification Process ◽  
Different Types ◽  
Before And After ◽  
Cleaning Technology

Gas from the gasification of pellets made from renewable sources of energy or from lower-quality fuels often contains a number of pollutants. This may cause technical difficulties during the gas use in internal combustion gas engines used for energy and heat cogeneration. Therefore, an adequate system of gas cleaning must be selected. In line with such requirements, this paper focuses on the characterization and comparison of gases produced from different types of biomass during gasification. The biomass tested was wood, straw, and hay pellets. The paper gives a detailed description and evaluation of the measurements from a fix-bed gasifier for the properties of the produced gases, raw fuels, tar composition, and its particle content before and after the cleaning process. The results of elemental composition, net calorific value, moisture, and ash content show that the cleaned gases are suitable for internal combustion engine-based cogeneration systems, but unsuitable for gas turbines, where a different cleaning technology would be needed.

scholarly journals Advanced development of metal oxide nanomaterials for H2 gas sensing applications

2021 ◽  
Author(s):  
Yushu Shi ◽  
Huiyan Xu ◽  
Tongyao Liu ◽  
Shah Zeb ◽  
Yong Nie ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Gas Sensors ◽  
Gas Sensing ◽  
The Past ◽  
Sensing Applications ◽  
The Future ◽  
Metal Oxide Nanomaterials ◽  
Nanomaterials Synthesis ◽  
Advanced Development

The scheme of the structure of this review includes an introduction from the metal oxide nanomaterials’ synthesis to application in H2 gas sensors—a vision from the past to the future.

Sign in / Sign up

Export Citation Format

Share Document