Krzysztof Jakub Stojek, Jan Felba, Damian Nowak, Karol Malecha, Szymon Kaczmarek and Patryk Tomasz Tomasz Andrzejak
This paper aims to perform thermal and mechanical characterization for silver-based sintered thermal joints. Layer quality affects thermal and mechanical performance, and it is…
Abstract
Purpose
This paper aims to perform thermal and mechanical characterization for silver-based sintered thermal joints. Layer quality affects thermal and mechanical performance, and it is important to achieve information about how materials and process parameters influence them.
Design/methodology/approach
Thermal investigation of the thermal joints analysis method was focused on determination of thermal resistance, where temperature measurements were performed using infrared camera. They were performed in two modes: steady-state analysis and dynamic analysis. Mechanical analysis based on measurements of mechanical shear force. Additional characterizations based on X-ray image analysis (image thresholding), optical microscope of polished cross-section and scanning electron microscope image analysis were proposed.
Findings
Sample surface modification affects thermal resistance. Silver metallization exhibits the lowest thermal resistance and the highest mechanical strength compared to the pure Si surface. The type of dynamic analysis affects the results of the thermal resistance.
Originality/value
Investigation of the layer quality influence on mechanical and thermal performance provided information about different joint types.
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Paweł Winiarski, Adam Kłossowicz, Wojciech Stęplewski, Damian Nowak and Andrzej Dziedzic
The purpose of this paper is to present the results of thermal analysis of cermet resistors made on alumina or LTCC substrate and polymer thick-film resistors embedded in FR-4…
Abstract
Purpose
The purpose of this paper is to present the results of thermal analysis of cermet resistors made on alumina or LTCC substrate and polymer thick-film resistors embedded in FR-4 substrate.
Design/methodology/approach
The study was performed using a thermal imaging method. The research was carried out with an additional consideration of such factors as sheet resistance (which depended on the type of resistive paste), the size and topology of element and the kind of contact material (Cu, Ag or Ni/Au). A few key points on the element were specified for which a more thorough analysis was carried out. The results were approximated by physically acceptable function which allowed to determine the influence of different mechanisms of heat transfer and determine their time and thermal constants.
Findings
The effectiveness of heat dissipation from resistor is determined by the type of substrate material, width of conductive paths, and contact material. The best results were observed for elements with wider conductive paths made of Cu or Ni/Au. The LTCC substrate ensures the fastest achieving of stable temperature on the component. The changes of the temperature gradient in time can be described by a formula consisting of two or three exponent parts, each one presenting different mechanism of change.
Research limitations/implications
These studies do not include more detailed determination of nature of found mechanisms of change. There has not also been established what form of the formula is more accurate physically description of the results for respective structure.
Originality/value
The results provide important data of the thermal properties of the chosen materials. This allows to determine their usability for specific applications where heat distribution plays an important role. The used analysis method is proven to provide reliable results and can be considered to be used for further studies in that subject.
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Damian Nowak, Andrzej Dziedzic, Zbigniew Żaluk, Henryk Roguszczak and Mariusz Węglarski
– The paper aims to investigate on the mechanical properties of surface-mount device (SMD) interconnections made on flexible and rigid substrates.
Abstract
Purpose
The paper aims to investigate on the mechanical properties of surface-mount device (SMD) interconnections made on flexible and rigid substrates.
Design/methodology/approach
The durability of joints to shear strength was measured with tensile machine. Investigations were carried out for 0402- and 0603-sized ceramic passives and integrated circuits in SOIC-8, TSSOP-8, XSON3 and XSON6 packages. Three types of flexible substrates (Kapton, Mylar and Pyralux) and two types of rigid substrates (LTCC and alumina) were used. SMD components were mounted with SAC solder or electrically conductive adhesive. Contact pads were made of Ag-based polymer paste on flexible substrates and PdAg-based cermet paste on ceramics. The shear strength was measured for as-made and long-term thermally aged test structures. The average durability and standard deviation were compared for different combination of materials. Moreover, mechanical properties of interconnections made of polymer thick-film pastes or electrically/thermally conductive adhesives between ceramic chips and flexible/ceramic substrates were investigated.
Findings
The mechanical properties of joints strongly depend on configuration of applied materials. Some of them exhibit high durability to shear strength, while other should not be recommended due to very weak connections. Additionally, long-term thermal ageing showed that exploitation of such connections at elevated temperature in some cases might increase their strength. However, for some materials, it leads to accelerated degradation of joints.
Originality/value
This paper provides practical information about SMD interconnections made with standard materials (lead-free solder, electrically/thermally conductive adhesives) and proposed non-standard procedures, e.g. assembling of ceramic chips with low temperature cermet or polymer thick-film conductive pastes.
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Oludolapo Ibrahim Olanrewaju, Sunday Ajiboye Babarinde, Nicholas Chileshe and Malindu Sandanayake
The Nigerian construction industry, like in most emerging economies has been slow with technological advances such as building information modeling (BIM). More so, the application…
Abstract
Purpose
The Nigerian construction industry, like in most emerging economies has been slow with technological advances such as building information modeling (BIM). More so, the application of BIM among Nigerian practitioners is rather limited to architects’ usage for schematic design and presentation of drawings. The purpose of this study is to enhance BIM’s uptake, this study explores the drivers for the implementation of BIM within the Nigerian construction industry.
Design/methodology/approach
An interpretivist epistemological design was adapted to extensively manually review and search the literature on BIM implementation drivers. Based on 14 drivers for BIM implementation drivers identified, a survey questionnaire was used to collect data from the Nigerian construction practitioners. The data obtained is then subjected to descriptive, inferential statistics and multivariate techniques such as factor analysis.
Findings
The study, through factor analysis, categorized the 14 drivers to BIM implementation into four principal factors. The factors are construction related-drivers; process digitalization and economic-related drivers; sustainability and efficiency-related drivers; and visualization and productivity-related drivers.
Practical implications
To effectively adopt BIM in the construction industry, it is necessary to identify the BIM implementing drivers, which can act as catalysts of change and, thus leading to sustained adoption of BIM. Therefore, the identified drivers and categorization of principal factors could provide managerial implications for better execution and adoption of BIM, as well as the creation of the required change for the BIM implementation.
Originality/value
The research provides insights into the implementation drivers of BIM in lesser studies in a developing country such as Nigeria. The study further contributes to this research sphere by using factor analysis to customize and contextualize the drivers that were previously identified.
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Karina Munari Pagan, Janaina de Moura Engracia Giraldi, Vishwas Maheshwari, André Luiz Damião de Paula and Jorge Henrique Caldeira de Oliveira
This study aims to analyse the impact of the country of origin of wines on cognitive processing and preferences through brain responses for consumers from the perspective of…
Abstract
Purpose
This study aims to analyse the impact of the country of origin of wines on cognitive processing and preferences through brain responses for consumers from the perspective of gender and the level of involvement.
Design/methodology/approach
A wine tasting experiment was performed using electroencephalography (EEG). The sample consisted of 40 students from an important Brazilian university. In the first group, the participants tasted two glasses of wine with Brazilian then French origins. In the second group, the participants only tasted one glass of wine, without the origin information. The wine was the same in both groups and from Brazilian origin. Throughout the tasting process, participants had their brain responses recorded via the EEG.
Findings
The main findings suggest that the country of origin did not have a significant influence on cognitive processing or preferences for consumers in general, neither for women nor consumers of high involvement. For men, there was greater cognitive processing for Brazilian wines. However, there was no preference for men among the origins of wines. For consumers with low involvement, there was a difference in cognitive processing, presenting a greater value for Brazil and without origin information. Also, for low-involvement consumers, a greater preference for wine from France was seen.
Originality/value
This study presents a new contribution to the literature by analysing the cognitive processing and preferences through brain responses for consumers from the perspective of gender and the level of involvement.