Search results

1 – 10 of 123
To view the access options for this content please click here
Article
Publication date: 25 June 2019

D.K. Kharbanda, N. Suri and P.K. Khanna

The purpose of this paper is to explore a new possibility of providing high-temperature stable lead-free interconnections for low-temperature co-fired ceramics (LTCC…

Downloads
91

Abstract

Purpose

The purpose of this paper is to explore a new possibility of providing high-temperature stable lead-free interconnections for low-temperature co-fired ceramics (LTCC) hotplate. For gas-sensing application, a temperature range of 200°C-400°C is usually required by the sensing film to detect different gases which imply the requirement of thermally stable interconnects. To observe the effect of parameters influencing power of the device, electro-thermal simulation of LTCC hotplate is also presented. Simulated LTCC hotplate is fabricated using the LTCC technology.

Design/methodology/approach

The proposed task is to fabricate LTCC hotplate with interconnects through vertical access. Dedicated via-holes generated on the LTCC hotplate are used to provide the interconnections. These interconnections are based on adherence and bonding mechanism between LTCC and thick film. COMSOL software is used for finite element method (FEM) simulation of the LTCC hotplate structure.

Findings

Thermal reliability of these interconnections is tested by continuous operation of hotplate at 350°C for 175 h and cycling durability test performed at 500°C. Additionally, vibration test is also carried out for the hotplate with no damage observed in the interconnections. An optimized firing profile to reproduce these interconnections along with the experimental flowchart is presented.

Research limitations/implications

Research activity includes design and fabrication of LTCC hotplate with metal to thick-film based interconnections through vertical access. Research work on interconnections based on adherence of LTCC and thick film is limited.

Practical implications

A new way of providing lead-free and reliable interconnections will be useful for gas sensor fabricated on LTCC substrate. The FEM results are useful for optimizing the design for developing low-power LTCC hotplate.

Originality/value

Adherence and bonding mechanism between LTCC and thick film can be used to provide interconnections for LTCC devices. Methodology for providing such interconnections is discussed.

Details

Soldering & Surface Mount Technology, vol. 32 no. 1
Type: Research Article
ISSN: 0954-0911

Keywords

To view the access options for this content please click here
Article
Publication date: 19 January 2015

Fatemeh Samaeifar, Hassan Hajghassem, Ahmad Afifi and Hassan Abdollahi

One of the key components of the micro-sensors is MEMS micro-hotplate. The purpose of this paper is to introduce a platinum micro-hotplate with the proper geometry using…

Downloads
1131

Abstract

Purpose

One of the key components of the micro-sensors is MEMS micro-hotplate. The purpose of this paper is to introduce a platinum micro-hotplate with the proper geometry using the analytical model based on the heat transfer analysis to improve both heating efficiency and time constant.

Design/methodology/approach

This analytical model exhibits that suitable design for the micro-hotplate can be obtained by the appropriate selection of square heater (LH) and tether width (WTe). Based on this model and requirements of routine sample loading, the size of LH and WTe are chosen 200 and 15 μm, respectively. In addition, a simple micro-fabrication process is adopted to form the suspended micro-heater using bulk micromachining technology.

Findings

The experimental results show that the heating efficiency and heating and cooling time constants are 21.27 K/mW and 2.5 ms and 2.1 ms, respectively, for the temperature variation from 300 to 400 K in the fabricated micro-hotplates which are in closed agreement with the results obtained from the analytical model with errors within 5 per cent.

Originality/value

Our design based on the analytical model achieves a combination of fast time constant and high heating efficiency that are comparable or superior to the previously published platinum micro-hotplate.

Details

Sensor Review, vol. 35 no. 1
Type: Research Article
ISSN: 0260-2288

Keywords

To view the access options for this content please click here
Article
Publication date: 23 December 2019

Lokesh Kulhari, Achu Chandran, Kanad Ray and P.K. Khanna

Low temperature co-fired ceramics (LTCC) technology-based micro-hotplates are of immense interest owing to their ruggedness, high temperature stability and reliability…

Abstract

Purpose

Low temperature co-fired ceramics (LTCC) technology-based micro-hotplates are of immense interest owing to their ruggedness, high temperature stability and reliability. The purpose of this paper is to study the role of thermal mass of LTCC-based micro-hotplates on the power consumption and temperature for gas-sensing applications.

Design/methodology/approach

The LTCC micro-hotplates with different thicknesses are designed and fabricated. The role of thermal mass on power consumption and temperature of these hotplates are simulated and experimentally studied. Also, a comparison study on the performance of LTCC and alumina-based hotplates of equivalent thickness is done. A thick film-sensing layer of tin oxide is coated on LTCC micro-hotplate and demonstrated for the sensing of commercial liquefied petroleum gas.

Findings

It is found from both simulation and experimental studies that the power consumption of LTCC hotplates was decreasing with the decrease in thermal mass to attain the same temperature. Also, the LTCC hotplates are less power-consuming than alumina-based one, owing to their superior thermal characteristics (low thermal conductivity, 3.3 W/ [m-K]).

Originality/value

This study will be beneficial for designing hotplates based on LTCC technology with low power consumption and better stability for gas-sensing applications.

Details

Microelectronics International, vol. 37 no. 1
Type: Research Article
ISSN: 1356-5362

Keywords

To view the access options for this content please click here
Article
Publication date: 23 July 2018

Wenbin Li, Weilin Xu and Xin Wang

Clothing is subject to a dynamic thermal transport process in its routine service in which the apparel and human body together with environment interact with each other…

Abstract

Purpose

Clothing is subject to a dynamic thermal transport process in its routine service in which the apparel and human body together with environment interact with each other. Understanding of the thermal transfer in this case should take the variations of human body and environment together with clothing attributes into consideration. The paper aims to discuss these issues.

Design/methodology/approach

Based on the purpose-built dynamic thermal and moisture tester, this study focuses on the thermal transfer of fabrics in different rotational motions. The energy consumption and power of the simulated human skin, the temperature and the thermal retention rate were monitored in the process of rotation of the testing platform with gradually increased rotating speed.

Findings

It has been found that the thermal transfer of a rotating fabric is greatly affected by the rotating speed, the angle of the fabric toward the moving direction and the attributes of the fabric such as its thickness, layers, structure and its fiber composition.

Practical implications

This study will benefit the understanding of the dynamic thermal interaction of human with the environment, and the designing of clothing with excellent thermal comfort.

Originality/value

This work reveals the dynamic thermal transfer of fabrics in rotational motions. It provides a platform to study the dynamic thermal behavior of clothing in daily use.

Details

International Journal of Clothing Science and Technology, vol. 30 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

To view the access options for this content please click here
Article
Publication date: 20 April 2015

Simon Annaheim, Li-chu Wang, Agnieszka Psikuta, Matthew Patrick Morrissey, Martin Alois Camenzind and René Michel Rossi

The purpose of this paper is to determine the validity and inter-/intra-laboratory repeatability of the first part of a novel, three-phase experimental procedure using a…

Abstract

Purpose

The purpose of this paper is to determine the validity and inter-/intra-laboratory repeatability of the first part of a novel, three-phase experimental procedure using a sweating Torso device.

Design/methodology/approach

Results from a method comparison study (comparison with the industry-standard sweating guarded hotplate method) and an inter-laboratory comparison study are presented.

Findings

A high correlation was observed for thermal resistance in the method comparison study (r=0.97, p<0.01) as well as in the inter-laboratory comparison study (r=0.99, p<0.01).

Research limitations/implications

The authors conclude that the first phase of the standardised procedure for the sweating Torso provides reliable data for the determination of the dry thermal resistance of single and multi-layer textiles, and is therefore suitable as standard method to be used by different laboratories with this type of device. Further work is required to validate the applicability of the method for textiles with high thermal resistance.

Originality/value

This study provides the first “round-robin” data for measuring thermal resistance using a Torso device. In future publications the authors will provide similar data examining the repeatability of measurements that quantify combined heat and mass transfer.

Details

International Journal of Clothing Science and Technology, vol. 27 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

To view the access options for this content please click here
Article
Publication date: 8 July 2019

Wenbin Li, Yunjing Jiang, Peiqing Jiang and Xin Wang

The mass transfer of textiles during movement is complicated as the energy consumption (EC) from skin, surface temperature of fabrics together with environment will work…

Abstract

Purpose

The mass transfer of textiles during movement is complicated as the energy consumption (EC) from skin, surface temperature of fabrics together with environment will work synergistically to determine the sensation and comfort of wearer. The purpose of this paper is to reveal the mass transfer in the human-textile-environment dynamic system.

Design/methodology/approach

With a simulated hotplate mounted on a rotational testing platform, this paper focuses on the dynamic mass transfer of a fabric so as to simulate the real-time mass transfer of clothing in movements.

Findings

It has been found that the EC and surface temperature (T) change against testing time, indicating the convex and concave shapes of the EC–t and Tt curves. The initial moisture regain of the fabric, rotational speed of the platform and the fiber materials of the fabric have shown a great effect on the dynamic mass transfer process.

Practical implications

Understanding the dynamic mass transfer of textiles will benefit the design of clothing with better comfort and will contribute to the well-being of wearers.

Originality/value

This work reveals the dynamic mass transfer of textiles in rotational movements. It contributes a new approach to studying the mass transfer of clothing in real service.

Details

International Journal of Clothing Science and Technology, vol. 31 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

Content available
Article
Publication date: 1 April 2002

Downloads
37

Abstract

Details

Pigment & Resin Technology, vol. 31 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

To view the access options for this content please click here
Article
Publication date: 1 September 1973

The range of magnetic and direct drive stirrers produced by Chemlab is described in a leaflet now available. The complete range is included, from the Minor Stirrer, which…

Abstract

The range of magnetic and direct drive stirrers produced by Chemlab is described in a leaflet now available. The complete range is included, from the Minor Stirrer, which is a small magnetic stirrer with a nylon coated top giving good performance at slow speeds, to their hotplate magnetic stirrer which has a circular hotplate working up to 400°C.

Details

Pigment & Resin Technology, vol. 2 no. 9
Type: Research Article
ISSN: 0369-9420

To view the access options for this content please click here
Article
Publication date: 31 August 2012

Michele Dominici, Bastien Pietropaoli and Frédéric Weis

The purpose of this paper is to report an inter‐disciplinary experience in building a context‐aware system that provides adapted functionalities to inhabitants of a smart…

Abstract

Purpose

The purpose of this paper is to report an inter‐disciplinary experience in building a context‐aware system that provides adapted functionalities to inhabitants of a smart home. The paper focuses on the management of uncertainty that is intrinsic to pervasive computing systems.

Design/methodology/approach

The paper presents the principles that characterize the context‐aware architecture: the acceptability‐driven design, where privacy and acceptability are favored; the awareness of the gap between the reality of human activity and the capabilities of the capture process; the step‐by‐step abstraction of contextual information; the management of uncertainty imprecision and ignorance at individual‐ and cross‐layer levels. The paper presents the principles and describes the system architecture, focusing on the management of uncertainty.

Findings

The authors built a layered architecture that manages and propagates uncertainty, imprecision and ignorance, allowing the recognition of ambiguous contexts and the provision of adapted functionalities. The paper illustrates this architecture and an application leveraging it.

Research limitations/implications

Future work will investigate the exploitation of feedback mechanisms and the recognition of context dynamics. These improvements will allow resolving inconsistencies and ambiguities in context information and improving the provision of functionalities in situations characterized by temporal developments.

Practical implications

The research aims at realizing the long‐term vision of smart homes that provide adapted functionalities to inhabitants: saving energy and improving comfort and quality of domestic life.

Originality/value

The paper introduces some principles that can be considered when designing a context‐aware system and presents an architecture that follows those principles. Researchers in the smart home and pervasive computing domains may consider this paper when designing their context‐aware architectures.

Details

International Journal of Pervasive Computing and Communications, vol. 8 no. 3
Type: Research Article
ISSN: 1742-7371

Keywords

To view the access options for this content please click here
Article
Publication date: 1 January 1991

Waycon Technology Ltd has available a range of advanced single and dual hotplates featuring variable temperature control from room temperature to 300°C with pre‐set…

Abstract

Waycon Technology Ltd has available a range of advanced single and dual hotplates featuring variable temperature control from room temperature to 300°C with pre‐set temperature setting and digital display. Excellent temperature control and rapid heating are achieved by the use of a large ceramic thick film positive temperature coefficient (PTC) heater with integral sensor.

Details

Microelectronics International, vol. 8 no. 1
Type: Research Article
ISSN: 1356-5362

1 – 10 of 123