Search results

1 – 10 of over 7000
Article
Publication date: 1 December 2005

Muthukumaran Packirisamy, Ion Stiharu, Xing Li and Gino Rinaldi

To establish an accurate and sensitive method to characterize the moisture content of a particular environment.

1995

Abstract

Purpose

To establish an accurate and sensitive method to characterize the moisture content of a particular environment.

Design/methodology/approach

This paper proposes a relatively simple humidity sensor design consisting of electrodes on a suitable substrate coated with a polyimide material. The changes in relative humidity are denoted by a corresponding change in the polyimide material's electrical resistance profile. The design proposed in this work can be microfabricated and integrated with electronic circuitry. This sensor can be fabricated on alumina or silicon substrates. The electrode material can be made up of nickel, gold or aluminum and the thickness of the electrodes ranges typically between 0.2 and 0.3 μm. The sensor consists of an active sensing layer on top of a set of electrodes. The design of the electrodes can be configured for both resistive and capacitive sensing.

Findings

The polyimide material's ohmic resistance changes significantly with humidity variations. Changes in resistance as large as 4‐6 orders of magnitude are attainable over the entire operational humidity range.

Research limitations/implications

As the sensitivity varies non‐linearly with the humidity, the measurement has to be carried out over a very wide range in order to calibrate the sensor. The sensitivity and output range of the sensor can be easily controlled by changing the electrode spacing or geometry.

Practical implications

The control of humidity is important in many applications ranging from bio‐medical to space exploration.

Originality/value

A simple, easy to fabricate and measure, and low cost resistive‐type humidity sensor was developed. The realized sensor is suitable for integrating with microfabrication. Hence, multiple sensors of varying sensitivities and output ranges could be integrated on the same chip. Over the last few years, newly emerging micro‐electro‐mechanical‐systems technology and micro‐fabrication techniques have gained popularity and importance in the miniaturization of a variety of sensors and actuators.

Details

Sensor Review, vol. 25 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 14 March 2024

Gülçin Baysal

The aim of this review is to present together the studies on textile-based moisture sensors developed using innovative technologies in recent years.

Abstract

Purpose

The aim of this review is to present together the studies on textile-based moisture sensors developed using innovative technologies in recent years.

Design/methodology/approach

The integration levels of the sensors studied with the textile materials are changing. Some research teams have used a combination of printing and textile technologies to produce sensors, while a group of researchers have used traditional technologies such as weaving and embroidery. Others have taken advantage of new technologies such as electro-spinning, polymerization and other techniques. In this way, they tried to combine the good working efficiency of the sensors and the flexibility of the textile. All these approaches are presented in this article.

Findings

The presentation of the latest technologies used to develop textile sensors together will give researchers an idea about new studies that can be done on highly sensitive and efficient textile-based moisture sensor systems.

Originality/value

In this paper humidity sensors have been explained in terms of measuring principle as capacitive and resistive. Then, studies conducted in the last 20 years on the textile-based humidity sensors have been presented in detail. This is a comprehensive review study that presents the latest developments together in this area for researchers.

Details

International Journal of Clothing Science and Technology, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 2 October 2023

Usama Afzal, Kanza Maryam, Fatima Afzal and Muhammad Aslam

The purpose of this study is to fabricate a highly sensitive humidity sensor for observing the humidity effect on a robot’s body as an application of the Internet of Things. The…

Abstract

Purpose

The purpose of this study is to fabricate a highly sensitive humidity sensor for observing the humidity effect on a robot’s body as an application of the Internet of Things. The sensor has been fabricated by depositing a thin sensing layer of nickel phthalocyanine (NiPc) between two silver electrodes.

Design/methodology/approach

The structure of the thin film was observed by X-ray diffraction, optical properties by UV Vis and surface morphology by scanning electron microscope. The capacitance and the resistance with respect to change in relative humidity from 0 to 100%RH have been measured by LCR meter at 1 kHz.

Findings

The sensor’s response time is 7.5 s and its recovery time is 3.7 s, with high sensitivity of 127,259 pF/%RH and 332.287 MΩ/%RH. The authors have also used a proposed sensor on a steel body and observed humidity values. The analysis of all measured values was performed through the classical and neutrosophic approaches. By comparing, the authors have observed that the neutrosophic approach is more efficient in analyzing the sensor data.

Originality/value

In this work, the authors will fabricate a capacitive and resistive-type humidity sensor using the thin film of NiPc. The structural, optical and morphological properties of NiPc thin film will be investigated with different characterization techniques. The electric properties, i.e. capacitance and resistance, will be measured at intervals with an LCR meter by changing relative humidity (%RH). Moreover, the measured data will be analyzed through different statistical approaches, as already used in [12].

Details

Sensor Review, vol. 43 no. 5/6
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 27 June 2023

Meixian Zhang, Yiding Ou, Haibing Yuan, Junlin Pan and Lei Ma

The purpose of this paper is to examine the practicability of the self-designed ambient humidity controllable pin-disc/rolling multifunctional friction and wear test device and to…

Abstract

Purpose

The purpose of this paper is to examine the practicability of the self-designed ambient humidity controllable pin-disc/rolling multifunctional friction and wear test device and to evaluate the friction and wear characteristics of materials under diverse ambient humidity conditions in different contact forms.

Design/methodology/approach

The practicability of the self-designed multifunctional friction tester was examined by the friction and wear tests of materials under different ambient humidity conditions [65%RH, 98%RH (relative humidity)] in diverse contact forms (pin/disc and rolling). Meanwhile, the friction and wear properties of pin/disc samples also rolling samples were assessed from three aspects: average friction coefficient, wear mass and wear morphology.

Findings

The results prove that the self-designed multifunctional friction tester has practicability. Therefore, it can be used to simulate the friction and wear tests of materials under diverse ambient humidity conditions in different contact forms. Besides, it is evident that the wear damage of pin/disc and rolling samples are greatly improved under high ambient humidity conditions. And when other conditions are identical, the higher the ambient humidity, the smaller the average friction coefficient, wear mass and wear damage degree of pin/disc also rolling samples.

Originality/value

This paper offers a self-designed multifunctional friction and wear test device. And the tester not only can realize the control of test ambient humidity, but also achieve the wear test of pin/disc or rolling contact forms. The design and production of the tester can offer convenience for the research of tribology, and provide fundamental guidance for the study of materials under high humidity condition in diverse contact forms.

Details

Industrial Lubrication and Tribology, vol. 75 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 6 July 2022

Mayumi Uemae, Tomohiro Uemae and Masayoshi Kamijo

The purpose of this study was to investigate the psychological response to changes in temperature and humidity near the skin, and the psychological factors of thermal discomfort.

Abstract

Purpose

The purpose of this study was to investigate the psychological response to changes in temperature and humidity near the skin, and the psychological factors of thermal discomfort.

Design/methodology/approach

The experiments involved changing the temperature and humidity from a neutral to a hot-humid environment, and vice versa, every 30 min. The psychological response to temperature (which ranged from 24 to 40°C) and humidity (which ranged from 30 to 80% relative humidity) was investigated.

Findings

The sensory scores shifted according to the direction of the change in temperature and humidity. The environment seemed to be evaluated relatively, whereby the sensory perception was dependent on the prior thermal environment. The psychological response to changes in temperature and humidity near the skin tended to shift from simple situational perceptions, such as feeling hot, to stifling and uncomfortable perceptions, and finally to the perception of dullness. Examining the psychological components revealed that the uncomfortable feeling was affected by “stifling” and “sweaty” perceptions with increasing temperature, by “stifling”, “sweaty”, and “sticky” perceptions with decreasing temperature, by “stifling”, “dull”, “sticky”, and “hot” perceptions with increasing humidity, and by “sweaty”, “dull”, and “humid” perceptions with decreasing humidity.

Originality/value

This study identified the psychological response that accompanies changes in temperature and humidity near the skin, as well as the psychological components of discomfort associated with changes in temperature and humidity. These results provide insights into the microclimate and thermal comfort of clothing.

Details

International Journal of Clothing Science and Technology, vol. 34 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

Article
Publication date: 19 July 2021

Kawaljit Singh Randhawa and Ashwin Patel

The mechanical and tribological properties of polymers and polymer composites vary with different environmental conditions. This paper aims to review the influence of humidity

Abstract

Purpose

The mechanical and tribological properties of polymers and polymer composites vary with different environmental conditions. This paper aims to review the influence of humidity/water conditions on various polymers and polymer composites' mechanical properties and tribological behaviors.

Design/methodology/approach

The influence of humidity and water absorption on mechanical and tribological properties of various polymers, fillers and composites has been discussed in this paper. Tensile strength, modulus, yield strength, impact strength, COF and wear rates of polymer composites are compared for different environmental conditions. The interaction between the water molecules and hydrophobic polymers is also represented.

Findings

Pure polymer matrices show somewhat mixed behavior in humid environments. Absorbed moisture generally plasticizes the epoxies and polyamides and lowers the tensile strength, yield strength and modulus. Wear rates of PVC generally decrease in humid environments, while for polyamides, it increases. Fillers like graphite and boron-based compounds exhibit low COF, while MoS2 particulate fillers exhibit higher COF at high humidity and water conditions. The mechanical properties of fiber-reinforced polymer composites tend to decrease as the rate of humidity increases while the wear rates of fiber-reinforced polymer composites show somewhat mixed behavior. Particulate fillers like metals and advanced ceramics reinforced polymer composites exhibit low COF and wear rates as the rate of humidity increases.

Originality/value

The mechanical and tribological properties of polymers and polymer composites vary with the humidity value present in the environment. In dry conditions, wear loss is determined by the hardness of the contacting surfaces, which may not effectively work for high humid environments. The tribological performance of composite constituents, i.e. matrix and fillers in humid environments, defines the overall performance of polymer composite in said environments.

Details

Industrial Lubrication and Tribology, vol. 73 no. 9
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 21 September 2015

Omar Alhartomy

The aim of this study is to investigate the humidity-sensing of polyaniline–zinc oxide (PANI–ZnO) nanocomposites. Humidity sensor has wide applications in drug industries, food…

Abstract

Purpose

The aim of this study is to investigate the humidity-sensing of polyaniline–zinc oxide (PANI–ZnO) nanocomposites. Humidity sensor has wide applications in drug industries, food industries and domestic purpose to regulate the humidity level.

Design/methodology/approach

PANI–ZnO composites were prepared by in situ polymerization method, and further humidity response was tested by using a two-probe sensor setup.

Findings

PANI-ZnO composites surface were modified by using camphor sulphonic acid. DC conductivity is due to the hopping of polorans. Thermal coefficient value varies from 1.7 to 2.3. The 30 weight per cent composite shows high sensitivity among other composites.

Research limitations/implications

These composites can be used only at room temperature or moderate temperature, i.e. below 280°C.

Practical implications

The composites are prepared in tetrapod shape that has a large surface area and more stability. Therefore, these materials would be the replacement for conventional materials.

Social implications

These sensors have many applications in food and drug preservation, domestic purposes, etc.

Originality/value

This work is original, and not being considered for publication elsewhere. In this work, the charge transport properties were evaluated based on the resistivity change when samples were exposed to humidity.

Details

Sensor Review, vol. 35 no. 4
Type: Research Article
ISSN: 0260-2288

Keywords

Article
Publication date: 2 May 2017

Vadimas Verdingovas, Salil Joshy, Morten Stendahl Jellesen and Rajan Ambat

The purpose of this study is to show that the humidity levels for surface insulation resistance (SIR)-related failures are dependent on the type of activators used in no-clean…

Abstract

Purpose

The purpose of this study is to show that the humidity levels for surface insulation resistance (SIR)-related failures are dependent on the type of activators used in no-clean flux systems and to demonstrate the possibility of simulating the effects of humidity and contamination on printed circuit board components and sensitive parts if typical SIR data connected to a particular climatic condition are available. This is shown on representative components and typical circuits.

Design/methodology/approach

A range of SIR values obtained on SIR patterns with 1,476 squares was used as input data for the circuit analysis. The SIR data were compared to the surface resistance values observable on a real device printed circuit board assembly. SIR issues at the component and circuit levels were analysed on the basis of parasitic circuit effects owing to the formation of a water layer as an electrical conduction medium.

Findings

This paper provides a summary of the effects of contamination with various weak organic acids representing the active components in no-clean solder flux residue, and demonstrates the effect of humidity and contamination on the possible malfunctions and errors in electronic circuits. The effect of contamination and humidity is expressed as drift from the nominal resistance values of the resistors, self-discharge of the capacitors and the errors in the circuits due to parasitic leakage currents (reduction of SIR).

Practical/implications

The methodology of the analysis of the circuits using a range of empirical leakage resistance values combined with the knowledge of the humidity and contamination profile of the electronics can be used for the robust design of a device, which is also important for electronic products relying on low current consumption for long battery lifetime.

Originality/value

Examples provide a basic link between the combined effect of humidity and contamination and the performance of electronic circuits. The methodology shown provides the possibility of addressing the climatic reliability of an electronic device at the early stage of device design by using typical SIR data representing the possible climate exposure.

Details

Circuit World, vol. 43 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 30 January 2020

Qingqing Song, Xudong Wang, Boyang Pan and Lei Wan

The purpose of this paper is to obtain the environmental factor, which has the greatest effect on the corrosion rate of Q235 carbon steel under thin electrolyte layer, and to…

Abstract

Purpose

The purpose of this paper is to obtain the environmental factor, which has the greatest effect on the corrosion rate of Q235 carbon steel under thin electrolyte layer, and to analyze the effect of this factor on the corrosion morphology, corrosion products and polarization process of Q235 carbon steel.

Design/methodology/approach

An electrochemical device, which can be used under thin electrolyte layer is designed to measure the corrosion current in different environments. Response surface methodology (RSM) is introduced to analyze the effect of environmental factors on corrosion rate. Scanning electron microscope (SEM) and X-ray diffraction (XRD) technique are used to analyze the results. The Tafel slopes of anode and cathode in different humidity and solution are calculated by least square method.

Findings

The three environmental factors are ranked according to importance, namely, humidity, temperature and chloride ion deposition rate. In a high humidity environment, the relative content of α-FeOOH in the corrosion product is high and the relative content of β-FeOOH is low. The higher the humidity, the lower the degree of anodic blockage, whereas the degree of cathodic blockage is independent of humidity. The above experiments confirm the effectiveness and efficiency of the device, indicating it can be used for the screening of corrosive environmental factors.

Originality/value

In this paper, an electrochemical device under thin film is designed, which can simulate atmospheric corrosion well. Subsequent SEM and XRD confirmed the reliability of the data measured by this device. The introduction of a scientific RSM can overcome the limitations of orthogonal experiments and more specifically and intuitively analyze the effects of environmental factors on corrosion rates.

Details

Anti-Corrosion Methods and Materials, vol. 67 no. 2
Type: Research Article
ISSN: 0003-5599

Keywords

Article
Publication date: 29 February 2008

Markus Weder, René M. Rossi, Cyril Chaigneau and Brice Tillmann

The purpose of this investigation is to measure seven different underwears on a sweating torso with differing relative air humidity (30, 50, 80 and 95 per cent RH) and at a fixed…

1101

Abstract

Purpose

The purpose of this investigation is to measure seven different underwears on a sweating torso with differing relative air humidity (30, 50, 80 and 95 per cent RH) and at a fixed ambient temperature of 30°C to determine the influence of the water vapour partial pressure of the environment on the moisture transport properties of various materials.

Design/methodology/approach

All measurements in this investigation were accomplished with the authors' sweating torso which simulates the thermal‐ and humidity release of the human body. Four different sweating rates (50, 75, 100 and 150 g/h*torso) were selected for this investigation.

Findings

It was established that the partial pressure difference did not correlate directly with the evaporative cooling. In general, higher evaporation rates were observed in the dry climate conditions. However, with low‐sweat rates, the highest relative humidity (95 per cent) generally resulted in greater evaporative cooling than the lowest surrounding humidity conditions (30 per cent). In this investigation, a blended fabric made of PES/Vinal exhibited the most efficient evaporative cooling for all the sweat rates, as well as for the four relative humidity conditions chosen.

Research limitations/implications

All received results are based on a surrounding temperature of 30°C (summer climate), for other temperatures the results may be different.

Originality/value

The investigation shows that both the relative humidity and the sweat rate have a major influence on the heat loss.

Details

International Journal of Clothing Science and Technology, vol. 20 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

1 – 10 of over 7000