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Article
Publication date: 8 February 2011

Rabindra N. Das, How T. Lin, John M. Lauffer and Voya R. Markovich

There has been increasing interest in the development of printable electronics to meet the growing demand for low‐cost, large‐area, miniaturized, flexible and lightweight devices…

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Abstract

Purpose

There has been increasing interest in the development of printable electronics to meet the growing demand for low‐cost, large‐area, miniaturized, flexible and lightweight devices. The purpose of this paper is to discuss the electronic applications of novel printable materials.

Design/methodology/approach

The paper addresses the utilization of polymer nanocomposites as it relates to printable and flexible technology for electronic packaging. Printable technology such as screen‐printing, ink‐jet printing, and microcontact printing provides a fully additive, non‐contacting deposition method that is suitable for flexible production.

Findings

A variety of printable nanomaterials for electronic packaging have been developed. This includes nanocapacitors and resistors as embedded passives, nanolaser materials, optical materials, etc. Materials can provide high‐capacitance densities, ranging from 5 to 25 nF/in2, depending on composition, particle size, and film thickness. The electrical properties of capacitors fabricated from BaTiO3‐epoxy nanocomposites showed a stable dielectric constant and low loss over a frequency range from 1 to 1,000 MHz. A variety of printable discrete resistors with different sheet resistances, ranging from ohm to Mohm, processed on large panels (19.5×24 inches) have been fabricated. Low‐resistivity materials, with volume resistivity in the range of 10−4‐10−6 ohm cm, depending on composition, particle size, and loading, can be used as conductive joints for high‐frequency and high‐density interconnect applications. Thermosetting polymers modified with ceramics or organics can produce low k and lower loss dielectrics. Reliability of the materials was ascertained by (Infrared; IR‐reflow), thermal cycling, pressure cooker test (PCT) and solder shock testing. The change in capacitance after 3× IR‐reflow and after 1,000 cycles of deep thermal cycling between −55°C and +125°C was within 5 per cent. Most of the materials in the test vehicle were stable after IR‐reflow, PCT, and solder shock.

Research limitations/implications

The electronic applications of printable, high‐performance nanocomposite materials such as adhesives (both conductive and non‐conductive), interlayer dielectrics (low‐k, low‐loss dielectrics), embedded passives (capacitors and resistors), and circuits, etc.. are discussed. Also addressed are investigations of printable optically/magnetically active nanocomposite and polymeric materials for fabrication of devices such as inductors, embedded lasers, and optical interconnects.

Originality/value

A thin film printable technology was developed to manufacture large‐area microelectronics with embedded passives, Z‐interconnects and optical waveguides, etc. The overall approach lends itself to package miniaturization because multiple materials and devices can be printed in the same layer to increase functionality.

Details

Circuit World, vol. 37 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 18 May 2010

Rabindra N. Das, Frank D. Egitto and Voya R. Markovich

Material formulation, structuring and modification are key to increasing the unit volume complexity and density of next generation electronic packaging products. Laser processing…

Abstract

Purpose

Material formulation, structuring and modification are key to increasing the unit volume complexity and density of next generation electronic packaging products. Laser processing is finding an increasing number of applications in the fabrication of these advanced microelectronic devices. The purpose of this paper is to discuss the development of new laser‐processing capabilities involving the synthesis and optimization of materials for tunable device applications.

Design/methodology/approach

The paper focuses on the application of laser processing to two specific material areas, namely thin films and nanocomposite films. The examples include BaTiO3‐based thin films and BaTiO3 polymer‐based nanocomposites.

Findings

A variety of new regular and random 3D surface patterns are highlighted. A frequency‐tripled Nd:YAG laser operating at a wavelength of 355 nm is used for the micromachining study. The micromachining is used to make various patterned surface morphologies. Depending on the laser fluence used, one can form a “wavy,” random 3D structure, or an array of regular 3D patterns. Furthermore, the laser was used to generate free‐standing nano and micro particles from thin film surfaces. In the case of BaTiO3 polymer‐based nanocomposites, micromachining is used to generate arrays of variable‐thickness capacitors. The resultant thickness of the capacitors depends on the number of laser pulses applied. Micromachining is also used to make long, deep, multiple channels in capacitance layers. When these channels are filled with metal, the spacings between two metallized channels acted as individual vertical capacitors, and parallel connection eventually produce vertical multilayer capacitors. For a given volume of capacitor material, theoretical capacitance calculations are made for variable channel widths and spacings. For comparison, calculations are also made for a “normal” capacitor, that is, a horizontal capacitor having a single pair of electrodes.

Research limitations/implications

This technique can be used to prepare capacitors of various thicknesses from the same capacitance layer, and ultimately can produce variable capacitance density, or a library of capacitors. The process is also capable of making vertical 3D multilayer embedded capacitors from a single capacitance layer. The capacitance benefit of the vertical multilayer capacitors is more pronounced for thicker capacitance layers. The application of a laser processing approach can greatly enhance the utility and optimization of new materials and the devices formed from them.

Originality/value

Laser micromaching technology is developed to fabricate several new structures. It is possible to synthesize nano and micro particles from thin film surfaces. Laser micromachining can produce a variety of random, as well as regular, 3D patterns. As the demand grows for complex multifunctional embedded components for advanced organic packaging, laser micromachining will continue to provide unique opportunities.

Details

Circuit World, vol. 36 no. 2
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 20 November 2009

Rabindra N. Das, Steven G. Rosser, Konstantinos I. Papathomas, Tim Antesberger and Voya R. Markovich

Embedded passives account for a very large part of today's electronic assemblies. This is particularly true for products such as cellular phones, camcorders, computers, and…

Abstract

Purpose

Embedded passives account for a very large part of today's electronic assemblies. This is particularly true for products such as cellular phones, camcorders, computers, and several critical defence devices. Market pressures for new products with more features, smaller size and lower cost demand smaller, compacter, simpler substrates. An obvious strategy is to reduce the number of surface mounted passives by embedding them in the substrate. In addition, current interconnect technology to accommodate surface mounted passives imposes certain limits on board design which constrain the overall system speed. Embedding passives is one way to minimize the functional footprint while at the same time improving performance. The purpose of this paper is to describe the development of a thin film technology based on ferroelectric‐epoxy polymer‐based flake‐free resin coated copper capacitive (RC3) nanocomposites to manufacture multilayer embedded capacitors.

Design/methodology/approach

This paper discusses thin film technology based on RC3 nanocomposites. In particular, recent developments in high capacitance, large area, thin film passives, and their integration in system in a package (SiP) are highlighted.

Findings

A variety of RC3 nanocomposite thin films ranging from 8 to 50 microns thick were processed on copper substrates by liquid coating. Multilayer embedded capacitors resulted in high capacitances of 16‐28 nF. The fabricated test vehicle also included two embedded resistor layers with resistances in the range of 15 Ω to 100 kΩ. To enable high performance devices, an embedded resistor must meet certain tolerances. The embedded resistors can be laser trimmed to a tolerance of <5 percent, which is usually acceptable for most applications. An extended embedded passives solution has been demonstrated, both through its high wireability designs and package performance, to be perfectly suited for SiP applications.

Research limitations/implications

This case study designed and fabricated an eight layer high density internal passive core and subsequently applied fine geometry three buildup layers to form a 3‐8‐3 structure. The passive core technology is capable of providing up to six layers of embedded capacitance and could be extended further.

Originality/value

A thin film technology based on ferroelectric‐epoxy polymer‐based flake‐free RC3 nanocomposites was developed to manufacture multilayer embedded capacitors. The overall approach lends itself to package miniaturization because capacitance can be increased through multiple layers and reduced thickness to give the desired values in a smaller area.

Details

Circuit World, vol. 35 no. 4
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 8 February 2008

Rabindra N. Das, Frank D. Egitto and Voya R. Markovich

The purpose of this paper is to discuss the use of epoxy‐based conducting adhesives in z‐axis interconnections.

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Abstract

Purpose

The purpose of this paper is to discuss the use of epoxy‐based conducting adhesives in z‐axis interconnections.

Design/methodology/approach

A variety of conductive adhesives with particle sizes ranging from 80 nm to 15 μm were laminated into printed wiring board substrates. SEM and optical microscopy were used to investigate the micro‐structures, conducting mechanism and path. The mechanical strength of the various adhesives was characterized by 90° peel test and measurement of tensile strength. Reliability of the adhesives was ascertained by IR‐reflow, thermal cycling, pressure cooker test (PCT), and solder shock. Change in tensile strength of adhesives was within 10 percent after 1,000 cycles of deep thermal cycling (DTC) between −55 and 125°C.

Findings

The volume resistivity of copper, silver and low‐melting point (LMP) alloy based paste were 5 × 10−4, 5 × 10−5 and 2 × 10−5 Ω cm, respectively. Volume resistivity decreased with increasing curing temperature. Adhesives exhibited peel strength with Gould's JTC‐treated Cu as high as 2.75 lbs/in. for silver, and as low as 1.00 lb/in. for LMP alloy. Similarly, tensile strength for silver, copper and LMP alloy were 3,370, 2,056 and 600 ψ, respectively. There was no delamination for silver, copper and LMP alloy samples after 3X IR‐reflow, PCT, and solder shock. Among all, silver‐based adhesives showed the lowest volume resistivity and highest mechanical strength. It was found that with increasing curing temperature, the volume resistivity of the silver‐filled paste decreased due to sintering of metal particles.

Research limitations/applications

As a case study, an example of silver‐filled conductive adhesives as a z‐axis interconnect construction for a flip‐chip plastic ball grid array package with a 150 μm die pad pitch is given.

Originality/value

A high‐performance Z‐interconnect package can be provided which meets or exceeds JEDEC level requirements if specific materials, design, and manufacturing process requirements are met, resulting in an excellent package that can be used in single and multi‐chip applications. The processes and materials used to achieve smaller feature dimensions, satisfy stringent registration requirements, and achieve robust electrical interconnections are discussed.

Details

Circuit World, vol. 34 no. 1
Type: Research Article
ISSN: 0305-6120

Keywords

Article
Publication date: 11 October 2019

Sasmita Mohapatra, Ajay Kumar Behera, Rabindra Mahapatra and Harish Das

The purpose of this paper is to present a unique model for the production–recycling–reuse of aluminium refreshment cans. It is presumed that disposed-off 250-ml aluminium cans are…

Abstract

Purpose

The purpose of this paper is to present a unique model for the production–recycling–reuse of aluminium refreshment cans. It is presumed that disposed-off 250-ml aluminium cans are collected from the retail outlet. The cans are thereafter arranged into non-tainted and tainted categories.

Design/methodology/approach

The current model considers all the factors, i.e. producing, recycling and remanufacturing, whereas the previous models provide emphasis only one factor. Six procedures were considered in the improvement of the mathematical model.

Findings

In this paper, a recycling–reuse model that remanufactures non-tainted aluminium beverage cans and uses regrind from damaged non-tainted aluminium beverage cans mixed with parent aluminium material in the production of new cans was developed and analysed to reduce the amount of aluminium beverage cans that are disposed off in a scrapyard. The model is assumed to have no shortcomings, and the different percentages regarding the classes of cans are taken to be deterministic.

Originality/value

The model incorporates several unique aspects, including accounting for the cost of land use and associated environmental damage through the calculation of a present value that is charged to the manufacturer.

Details

Journal of Modelling in Management, vol. 15 no. 1
Type: Research Article
ISSN: 1746-5664

Keywords

Article
Publication date: 8 June 2021

Sanatan Das, Akram Ali and Rabindra Nath Jana

Outstanding features such as thermal conductivity and superior electrical conductivity of nanofluids unfold a new window in the context of their extensive applications in…

Abstract

Purpose

Outstanding features such as thermal conductivity and superior electrical conductivity of nanofluids unfold a new window in the context of their extensive applications in engineering and industrial domains. The purpose of this study to simulate numerically the magneto-nanofluid flow and heat transfer over a curved stretching surface. Heat transport is explored in the presence of viscous dissipation. At the curved surface, the convective boundary condition is adopted. Three different nanoparticles, namely, copper, aluminium oxide and titanium dioxide are taken into consideration because of easily available in nature.

Design/methodology/approach

The basic flow equations are framed in terms of curvilinear coordinates. The modelled partial differential equations are transformed into a system of non-linear ordinary differential equations by means of appropriate similarity transformation. The subsequent non-linear system of equations is then solved numerically by using the Runge–Kutta–Felhberg method with the shooting scheme via bvp4c MATLAB built-in function. Impacts of various physical parameters on velocity, pressure and temperature distributions, local skin-friction coefficient, local Nusselt number and wall temperature are portrayed through graphs and tables followed by a comprehensive debate and physical interpretation.

Findings

Graphical results divulge that augmenting values of the magnetic parameter cause a decline in velocity profiles and stream function inside the boundary layer. The magnitude of the pressure function inside the boundary layer reduces for higher estimation of curvature parameter, and it is also zero when the curvature parameter goes to infinity. Furthermore, the temperature is observed in a rising trend with growing values of the magnetic parameter and Biot number.

Practical implications

This research study is very pertinent to the expulsion of polymer sheet and photographic films, metallurgical industry, electrically-conducting polymer dynamics, magnetic material processing, rubber and polymer sheet processing, continuous casting of metals, fibre spinning, glass blowing and fibre, wire and fibre covering and sustenance stuff preparing, etc.

Originality/value

Despite the huge amount of literature available, but still, very little attention is given to simulate the flow configuration due to the curved stretching surface with the convective boundary condition. Very few papers have been examined on this topic and found that its essence inside the boundary layer is not any more insignificant than on account of a stretching sheet. A numerical comparison with the published works is conducted to verify the accuracy of the present study.

Details

World Journal of Engineering, vol. 18 no. 6
Type: Research Article
ISSN: 1708-5284

Keywords

Article
Publication date: 1 January 2014

Sunil Kumar Satpathy, Rabindra K. Maharana and Ashok Kumar Das

The aim of this paper is to investigate the scholarly communications in open access journals of library & information science and to study the key dimensions of these…

1936

Abstract

Purpose

The aim of this paper is to investigate the scholarly communications in open access journals of library & information science and to study the key dimensions of these publications.

Design/methodology/approach

For the analysis of the study, top ten open access journals of 2011, which were indexed in SCOPUS, have been selected. The authors employed necessary bibliometric measures to analyze different publication parameters.

Findings

It is found that the contribution of articles in these top ten open access journals in 2011 is good, i.e. 37.3 percent. Single authored papers are found to be the highest (40.48 percent), followed by two-authored and then three-authored papers. The degree of collaboration is found to be between 0.33 and 0.8. The numbers of citations used in the paper are also good (average 21.48 percent paper). In regards to ranking of country productivity, the USA topped the list.

Research limitations/implications

This paper focuses on the publication traits of top ten open access journals of library & information science of the year 2011. A total of 373 papers from these ten journals are analyzed. Further studies can include more open access journals of this field for a period of more than one year.

Practical implications

Scholars can benefit from insights into the scholarly contributions of top ten open access journals of 2011 in the field of library & information science.

Originality/value

This paper provides valuable insights into the nature of academic publishing of open access journals of library & information science. It can help the researchers, professionals, teachers and students to understand the top open access journals, valuable contributions, highly cited journals, country productivity, and other parameters.

Details

Collection Building, vol. 33 no. 1
Type: Research Article
ISSN: 0160-4953

Keywords

Article
Publication date: 1 February 2023

Sakti Ranjan Dash, Maheswar Sethi and Rabindra Kumar Swain

The purpose of this paper is to examine the impact of working capital management (WCM) on profitability under different financial conditions (constraint/unconstraint) and WCM…

Abstract

Purpose

The purpose of this paper is to examine the impact of working capital management (WCM) on profitability under different financial conditions (constraint/unconstraint) and WCM policy (aggressive/conservative). Furthermore, the study investigates the existence of optimal working capital levels under different financial conditions and WCM policy.

Design/methodology/approach

Two-step system generalized method of moments and fixed effect models are used to analyze the data collected from Prowess database from 2011 to 2020 for a sample of 1,104 Indian manufacturing companies.

Findings

The study finds an inverted U-shaped relationship between working capital and profitability in all financial conditions and working capital policy. This finding advocates the existence of an optimal level of working capital that equates the costs and benefits of holding working capital to maximize the companies’ profitability. However, holding working capital beyond the optimal level negatively affects profitability. Companies under financial constraints with aggressive working capital policies have the lowest optimal cash conversion cycle (CCC). Furthermore, the relationship of working capital with profitability and the optimal CCC varies owing to firm age and industry group.

Originality/value

To the best of the authors’ knowledge, this is the first paper that incorporates the impact of working capital on firm’s performance from both financial constraint (unconstraint) and aggressive (conservative) working capital policy perspectives in the Indian context. Furthermore, this study also contributes in terms of reflecting the effect of firm age and industry in determining the optimum CCC of the firms.

Details

Journal of Indian Business Research, vol. 15 no. 3
Type: Research Article
ISSN: 1755-4195

Keywords

Article
Publication date: 19 April 2022

Prosenjit Ghosh and Sabyasachi Mukherjee

The study aims to cluster the travellers based on their social media interactions as well as to find the different segments with similar and dissimilar categories according to…

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Abstract

Purpose

The study aims to cluster the travellers based on their social media interactions as well as to find the different segments with similar and dissimilar categories according to traveller's choice. The study also aims to understand the behaviour of clusters of the travellers towards destination selection and accordingly make the tour packages in order to improve tourists' satisfaction and gain viable benefits.

Design/methodology/approach

Agglomerative hierarchical clustering with Ward's minimum variance linkage algorithm and model-based clustering with parameterized finite Gaussian mixture models has been implemented to achieve the respective goals. The dimension reduction (DR) technique was introduced for better visualizing clustering structure obtained from a finite mixture of Gaussian densities.

Findings

A total of 980 travellers have been clustered into 8 different interest groups according to their tourism destinations selection across East Asia based on individual social media feedback. For selecting the optimal number of clusters as well as the behaviour of the interested travellers groups, both these proposed methods have shown remarkable similarities. DR technique ensures the reduction in dimensionality with seven directions, of which the first two directions explained 95% of total variability.

Practical implications

Tourism organizations focus on marketing efforts to promote the most attractive benefits to the clusters of travellers. By segmenting travellers of East Asia into homogeneous groups, it is feasible to choose a similar area to test different marketing techniques. Finally, it can be identified to which segments, new respondents or potential clients belong; consequently, the tourism organizations can design the tour packages.

Originality/value

The study has uniqueness in two aspects. Firstly, the study empirically revealed tourists' experience and behavioural intention to select tourism destinations and secondly, it finds quantifiable insights into the tourism phenomenon in East Asia, which helps tourism organizations to understand the buying behaviours of tourists' segments. Finally, the application of clustering algorithms to achieve the purpose of this study and the findings are very new in the literature on tourism, to understand the tourist behaviour towards destination selection based on social media reviews.

Details

Journal of Hospitality and Tourism Insights, vol. 6 no. 2
Type: Research Article
ISSN: 2514-9792

Keywords

Content available
Book part
Publication date: 19 July 2023

Abstract

Details

Inclusive Developments Through Socio-economic Indicators: New Theoretical and Empirical Insights
Type: Book
ISBN: 978-1-80455-554-5

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