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1 – 10 of over 42000Tirthankar Jana and Tapan Kumar Dhar
The purpose of this paper is to develop an inorganic-organic hybrid emulsion polymer using grafted hyperbranched alkyd modified with nanometal oxide and to study the performance…
Abstract
Purpose
The purpose of this paper is to develop an inorganic-organic hybrid emulsion polymer using grafted hyperbranched alkyd modified with nanometal oxide and to study the performance of the developed hybrid emulsion in paint formulation with respect to antimicrobial and other properties.
Design/methodology/approach
A novel hybrid emulsion polymer was synthesized by grafting of vinyl acetate (VAM), vinyl ester of versatic acid (VeoVa 10) monomers onto hyperbranched alkyd resin and incorporation of nano magnesium oxide (MgO) into the hybrid resin matrix during dispersion of resin in water. Subsequently, paint was prepared by using this hybrid emulsion followed by a performance study.
Findings
The performance of nano MgO modified into VAM and VeoVa 10 grafted hyperbranched alkyd resulted in unique properties of coating especially antimicrobial activity.
Research limitations/implications
In the present study, soya fatty acid, polyol and di basic acid have been used to prepare hyperbranched alkyd by condensation polymerization. Monomers like VAM and VeoVa 10 used for grafting onto hyperbranched alkyd and nano MgO have been incorporated into hybrid resin matrix during emulsification of hybrid resin in water.
Practical implications
Grafting of VAM and VeoVa 10 onto hyperbranched alkyd along with in situ incorporation of nano MgO in resin matrix is an effective technique to achieve excellent coating properties.
Originality/value
Nano MgO modified VAM and VeoVa 10 grafted hyperbranched alkyd-based hybrid emulsion can be used as binder in water-based metal primer, direct to metal (DTM) coating as well as topcoat application. The developed system has antimicrobial properties as well as superior mechanical properties.
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Ashish Paul, Bhagyashri Patgiri and Neelav Sarma
Flow induced by rotating disks is of great practical importance in several engineering applications such as rotating heat exchangers, turbine disks, pumps and many more. The…
Abstract
Purpose
Flow induced by rotating disks is of great practical importance in several engineering applications such as rotating heat exchangers, turbine disks, pumps and many more. The present research has been freshly displayed regarding the implementation of an engine oil-based Casson tri-hybrid nanofluid across a rotating disk in mass and heat transferal developments. The purpose of this study is to contemplate the attributes of the flowing tri-hybrid nanofluid by incorporating porosity effects and magnetization and velocity slip effects, viscous dissipation, radiating flux, temperature slip, chemical reaction and activation energy.
Design/methodology/approach
The articulated fluid flow is described by a set of partial differential equations which are converted into one set of higher-order ordinary differential equations (ODEs) by using convenient conversions. The numerical solution of this transformed set of ODEs has been spearheaded by using the effectual bvp4c scheme.
Findings
The acquired results show that the heat transmission rate for the Casson tri-hybrid nanofluid is intensified by, respectively, 9.54% and 11.93% when compared to the Casson hybrid nanofluid and Casson nanofluid. Also, the mass transmission rate for the Casson tri-hybrid nanofluid is augmented by 1.09% and 2.14%, respectively, when compared to the Casson hybrid nanofluid and Casson nanofluid.
Originality/value
The current investigation presents an educative response on how the flow profiles vary with changes in the inevitable flow parameters. As per authors’ knowledge, no such scrutinization has been carried out previously; therefore, our results are novel and unique.
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Mendiola Teng-Calleja, Jaimee Felice Caringal-Go, Ma. Tonirose D. Mactal, Jonah L. Fabul, Rhoger Marvin H. Reyes, Ed Joseph Bulilan, Clarisse Aeaea M. Kilboy and Raquel Cementina-Olpoc
The purpose of the study is to explore the experiences and sense-making of middle managers in transitioning to and implementing hybrid work arrangements.
Abstract
Purpose
The purpose of the study is to explore the experiences and sense-making of middle managers in transitioning to and implementing hybrid work arrangements.
Design/methodology/approach
Using the lens and analytical procedures of interpretative phenomenological analysis, data were collected during the transition time at the tail end of the COVID-19 pandemic as many organizations were navigating the hybrid work setup. In-depth semi-structured interviews were conducted with 12 middle managers from various organizations in the Philippines that have been implementing a hybrid work arrangement for at least 3 months.
Findings
Findings illustrate the challenges experienced by the middle managers in facilitating a smooth transition to onsite work, managing adjustments on when and where to work and bridging the imperatives of top management as well as the preferences of team members (managing upward and downward). The results describe strategies used by middle managers to balance deliverables and employee needs while demonstrating compassionate leadership in relating with direct reports. The middle managers also engaged in self-care, used reframing and sought support from family and peers to cope with challenges.
Practical implications
The findings exemplified how the middle managers experience of transitioning to hybrid work reflect various contextual and cultural nuances. These external realities must be considered in providing support to these groups of employees particularly in developing leadership programs that addresses their social and emotional needs.
Originality/value
The paper contributes to the limited research on middle managers' experiences in a hybrid work setup despite their critical role as change agents responsible for leading teams (van Dam et al., 2021).
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J. Sharana Basavaraja, Sathish Sharma and Sathish Jain
The non‐recessed hybrid journal bearings of cylindrical type, when operating at higher rotational speeds can suffer self‐exited vibrations(oil‐whirl Instability), which can cause…
Abstract
Purpose
The non‐recessed hybrid journal bearings of cylindrical type, when operating at higher rotational speeds can suffer self‐exited vibrations(oil‐whirl Instability), which can cause excessive rotor motion causing bearing and sometimes total machine failure. The multi‐lobe journal bearing exhibits better stability as well as a superior capability to suppress oil‐whirl. The paper aims to present a theoretical study pertaining to a two‐lobe hole‐entry hybrid journal bearing by considering the combined influence of surface roughness and journal misalignment on the performance of the bearing.
Design/methodology/approach
The average Reynolds equation governing the flow of lubricant in the clearance space between the rough bearing surfaces together with the equation of flow through a capillary restrictor has been solved using FEM. The bearing performance characteristics have been simulated for a two‐lobe hole‐entry hybrid journal bearing for the various values of offset factor, restrictor design parameter, surface roughness parameter, surface pattern parameter and journal misalignment parameters.
Findings
The two‐lobe hole‐entry hybrid journal bearing system with an offset factor greater than one indicates significant improvement of the order of 15‐25 percent in the values of direct stiffness and direct damping coefficients compared to a circular hole‐entry hybrid journal bearing system. Also the lubricant flow of a two‐lobe hole‐entry hybrid journal bearing is reduced by 25 percent vis‐à‐vis circular bearing.
Originality/value
The present work is original of its kind, in case of two‐lobe hole‐entry hybrid journal bearing. The results are quite useful for the bearing designer.
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C. Pornet, S. Kaiser, A.T. Isikveren and M. Hornung
The aim of this paper is to assess the potential of fuel-battery hybrid narrow-body (180PAX) transport aircraft according to different design ranges for an entry-into-service…
Abstract
Purpose
The aim of this paper is to assess the potential of fuel-battery hybrid narrow-body (180PAX) transport aircraft according to different design ranges for an entry-into-service (EIS) of 2035.
Design/methodology/approach
The philosophy used in the design of the twin-engine fuel-battery hybrid concept is to use the power of an electric motor during cruise to drive a single propulsive device, whereas the other one is powered conventionally by an advanced gas turbine. A methodology for the sizing and performance assessment of hybrid energy aircraft was previously proposed by the authors. Based on this methodology, the overall sizing effects at aircraft level are considered to size the hybrid aircraft to different range applications. To evaluate the hybrid concept, performance was contrasted against a conventional aircraft projected to EIS 2035 and sized for identical requirements. Additionally, sensitivity of the prospects against different battery technology states was analysed.
Findings
The best suited aircraft market for the application of the fuel-battery hybrid transport aircraft concept considered is the regional segment. Under the assumption of a battery-specific energy of 1.5 kWh/kg, block fuel reduction up to 20 per cent could be achieved concurrently with a gate-to-gate neutral energy consumption compared to an advanced gas-turbine aircraft. However, a large increase in maximum take-off weight (MTOW) occurs resulting from battery weight, the additional electrical system weight, and the cascading sizing effects. It strongly counteracts the benefit of the hybrid-electric propulsion technology used in this concept for lower battery-specific energy and for longer design ranges.
Practical implications
The findings will contribute to the evaluation of the feasibility and impact of hybrid energy transport aircraft as potential key enablers of the European and US aeronautical program goals towards 2035.
Originality/value
The paper draws its value from the consideration of the overall sizing effects at aircraft level and in particular the impact of the hybrid-electric propulsion system to investigate the prospects of fuel-battery hybrid narrow-body transport aircraft sized at different design ranges.
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In order to identify and quantify the size and shape of the rapidly changing complexion of the market for hybrid microelectronics, in 1987 ISHM launched a survey in Europe of the…
Abstract
In order to identify and quantify the size and shape of the rapidly changing complexion of the market for hybrid microelectronics, in 1987 ISHM launched a survey in Europe of the market for thin‐film, thick‐film and surface‐mount‐on‐PCB hybrids for the periods 1980, 1986 and 1990. The survey aimed to obtain a hierarchical breakdown of the markets also into technology and application sectors. The general findings are reported. The credibility and quantity of the survey are considered in the context of the market for electronic equipment in Europe for 1987 and 1990. In electronics there is a continuing pressure to reduce prices and therefore adjustments should not be made for inflation. A growth in market value is thus a true reflection of a larger growth in market volume and a continuing increase in complexity. Thus, the 11% CAGR for 1986–1990 reflects a growth in equipment volumes of 20% over the 4 year period. Manufacturers will have to design and build increasingly complex circuits at a higher throughput and lower cost, at an increasing pace. It is not a business for faint hearts. Clearly the growth potential for the hybrid microelectronics market should be considered in the context of the equipment market, in order to judge the relative growth. In order to distinguish between the hybrid and PCB industries, the survey has aimed to estimate the growth in the developing market for hybrids using substrates up to 6 in. × 4 in. (Eurocard), not including the larger SMAs on PCBs for which there is a huge market growth potential. The immediate opportunity is from miniaturisation and cost reduction using hybrid microelectronics. The major push in technological emphasis in modern hybrids comes from the need for high‐density interconnection to support increasingly complex VLSI in high‐pin‐count surface‐mount micropackages and high‐performance substrates to support VHSIC and high‐performance circuits. Hence there is a major shift in hybrid microelectronics technology emphasis towards high‐density surface‐mount assemblies on PCB and other organic substrates. The total hybrid market sub‐divided among the basic three technologies reveals this emphasis. The portents are clear, and those who intend to succeed, or even simply survive, need to be aware of the shift in emphasis and prepare to diversify or establish strengths in niche applications.
Haiou Zhang, Xiangping Wang, Guilan Wang and Yang Zhang
The purpose of this paper is to report a new direct metal manufacturing method which integrates freeform deposition process and micro rolling process, introduce the manufacturing…
Abstract
Purpose
The purpose of this paper is to report a new direct metal manufacturing method which integrates freeform deposition process and micro rolling process, introduce the manufacturing principle and show the advantages of this method.
Design/methodology/approach
This paper introduces the hybrid manufacturing principle and devices first. Then, the key parameters of hybrid manufacturing process are studied by contrast experiments. The results of comparisons of manufacturing accuracy, microstructure and tensile test between freeform fabricated parts and hybrid manufactured parts show the advantages of this new direct manufacturing method.
Findings
The experiments results show that the accuracy of hybrid manufacturing method is improved obviously comparing with arc-based freeform deposition manufacturing method; the microstructure of the hybrid manufacturing part turns into cellular crystal instead of dendrite; the tensile strength of the part increases by 33 percent and the tensile deformation improved more than two times.
Originality/value
The paper presents a new hybrid direct metal manufacturing method for the first time. The hybrid manufacturing devices are developed. The experiments results show that the hybrid manufacturing method can be used on directly fabricating large metal components with outstanding quality, efficiency and low cost. The application prospect is great.
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M.P. Jenarthanan and R. Jeyapaul
The purpose of this paper is to report the preparation, characterisation and machinability of resin hybrid GFRP composites, which are made of glass fibre and the mixture of epoxy…
Abstract
Purpose
The purpose of this paper is to report the preparation, characterisation and machinability of resin hybrid GFRP composites, which are made of glass fibre and the mixture of epoxy & polyester resin.
Design/methodology/approach
Resin hybrid GFRP laminates containing 0, 20 and 40wt% of polyester resin with the epoxy resin are prepared by conventional hand layup technique using glass fibre as the reinforcement. The variation of break load and shear strength for three different combinations of epoxy and polyester resin are studied by ASTM. A plan of experiment based on Taguchi was established with prefixed cutting parameters and the machining was performed. A stylus type profilometer to examine the surface roughness and shop microscope to examine the delamination of resin hybrid GFRP laminates were used. An analysis of variance (ANOVA) was performed to investigate the cutting characteristics of resin hybrid GFRP composite materials using solid carbide end mill. The correlation was obtained by multiple‐variable linear regression using Minitab 14 software.
Findings
Taguchi analysis reveals that the resin hybrid GFRP laminate provides better machinability in terms of surface roughness and delamination when compared to homogenous GFRP laminates (pure epoxy resin). Polyester resin enhances the machinability of the GFRP laminates.
Research limitations/implications
The machinability of the resin hybrid GFRP laminates can be improved further by modifying the polyester resin percentage.
Originality/value
The resin hybrid GFRP laminates so developed can be used in aircraft and aerospace applications to increase the shear and work of fracture properties.
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The purpose of this paper is to propose two hybrid forecasting models which integrate available ones. A hybrid contaminated normal distribution (CND) model accurately reflects the…
Abstract
Purpose
The purpose of this paper is to propose two hybrid forecasting models which integrate available ones. A hybrid contaminated normal distribution (CND) model accurately reflects the non‐normal features of monthly S&P 500 index returns, and a hybrid GARCH model captures a serial correlation with respect to volatility. The hybrid GARCH model potentially enables financial institutions to evaluate long‐term investment risks in the S&P 500 index more accurately than current models.
Design/methodology/approach
The probability distribution of an expected investment outcome is generated with a Monte Carlo simulation. A taller peak and fatter tails (kurtosis), which the probability distribution of monthly S&P 500 index returns contains, is produced by integrating a CND model and a bootstrapping model. The serial correlation of volatilities is simulated by applying a GARCH model.
Findings
The hybrid CND model can simulate the non‐normality of monthly S&P 500 index returns, while avoiding the influence of discrete observations. The hybrid GARCH model, by contrast, can simulate the serial correlation of S&P 500 index volatilities, while generating fatter tails. Long‐term investment risks in the S&P 500 index are affected by the serial correlation of volatilities, not the non‐normality of returns.
Research limitations/implications
The hybrid models are applied only to the S&P 500 index. Cross‐sectional correlations among different asset groups are not examined.
Originality/value
The proposed hybrid models are unique because they combine available ones with a decision tree algorithm. In addition, the paper clearly explains the strengths and weaknesses of existing forecasting models.
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Kalidas Das and Pinaki Ranjan Duari
Several graphs, streamlines, isotherms and 3D plots are illustrated to enlighten the noteworthy fallouts of the investigation. Embedding flow factors for velocity, induced…
Abstract
Purpose
Several graphs, streamlines, isotherms and 3D plots are illustrated to enlighten the noteworthy fallouts of the investigation. Embedding flow factors for velocity, induced magnetic field and temperature have been determined using parametric analysis.
Design/methodology/approach
Ternary hybrid nanofluids has outstanding hydrothermal performance compared to classical mono nanofluids and hybrid nanofluids owing to the presence of triple tiny metallic particles. Ternary hybrid nanofluids are considered as most promising candidates in solar energy, heat exchangers, electronics cooling, automotive cooling, nuclear reactors, automobile, aerospace, biomedical devices, food processing etc. In this work, a ternary hybrid nanofluid flow that contains metallic nanoparticles over a wedge under the prevalence of solar radiating heat, induced magnetic field and the shape factor of nanoparticles is considered. A ternary hybrid nanofluid is synthesized by dispersing iron oxide (Fe3O4), silver (Ag) and magnesium oxide (MgO) nanoparticles in a water (H2O) base fluid. By employing similarity transformations, we can convert the governing equations into ordinary differential equations and then solve numerically by using the Runge–Kutta–Fehlberg approach.
Findings
There is no fund for the research work.
Social implications
This kind of study may be used to improve the performance of solar collectors, solar energy and solar cells.
Originality/value
This investigation unfolds the hydrothermal changes of radiative water-based Fe3O4-Ag-MgO-H2O ternary hybrid nanofluidic transport past a static and moving wedge in the presence of solar radiating heating and induced magnetic fields. The shape factor of nanoparticles has been considered in this study.
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