bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical analysis of compact plate-fin heat exchangers for aerospace applications
Authors: Chennu Ranganayakulu 
Published: January 2018

Purpose
The purpose of this study is to find the thermo-hydraulic performances of compact heat exchangers (CHE’s), which are strongly depending upon the prediction of performance of various types of heat transfer surfaces such as offset strip fins, wavy fins, rectangular fins, triangular fins, triangular and rectangular perforated fins in terms of Colburn “j” and Fanning friction “f” factors.

Design/methodology/approach
Numerical methods play a major role for analysis of compact plate-fin heat exchangers, which are cost-effective and fast. This paper presents the on-going research and work carried out earlier for single-phase steady-state heat transfer and pressure drop analysis on CHE passages and fins. An analysis of a cross-flow plate-fin compact heat exchanger, accounting for the individual effects of two-dimensional longitudinal heat conduction through the exchanger wall, inlet fluid flow maldistribution and inlet temperature non-uniformity are carried out using a Finite Element Method (FEM).

Findings
The performance deterioration of high-efficiency cross-flow plate-fin compact heat exchangers have been reviewed with the combined effects of wall longitudinal heat conduction and inlet fluid flow/temperature non-uniformity using a dedicated FEM analysis. It is found that the performance deterioration is quite significant in some typical applications due to the effects of wall longitudinal heat conduction and inlet fluid flow non-uniformity on cross-flow plate-fin heat exchangers. A Computational Fluid Dynamics (CFD) program FLUENT has been used to predict the design data in terms of “j” and “f” factors for plate-fin heat exchanger fins. The suitable design data are generated using CFD analysis covering the laminar, transition and turbulent flow regimes for various types of fins.

Originality/value
The correlations for the friction factor “f” and Colburn factor “j” have been found to be good. The correlations can be used by the heat exchanger designers and can reduce the number of tests and modification of the prototype to a minimum for similar applications and types of fins.
A roadmap for driving customer word-of-mouth
Authors: Keiningham Timothy Lee , Rust Roland T. , Lariviere Bart , Aksoy Lerzan , Williams Luke 
Published: January 2018

Purpose
Managers seeking to manage customer word-of-mouth (WOM) behavior need to understand how different attitudinal drivers (e.g. satisfaction, positive and negative emotion, commitment, and self-brand connection) relate to a range of WOM behaviors. They also need to know how the effects of these drivers are moderated by customer characteristics (e.g. gender, age, income, country). The paper aims to discuss these issues.

Design/methodology/approach
To investigate these issues a built a large-scale multi-national database was created that includes attitudinal drivers, customer characteristics, and a full range of WOM behaviors, involving both the sending and receiving of both positive and negative WOM, with both strong and weak ties. The combination of sending-receiving, positive-negative and strong ties-weak ties results in a typology of eight distinct WOM behaviors. The investigation explores the drivers of those behaviors, and their moderators, using a hierarchical Bayes model in which all WOM behaviors are simultaneously modeled.

Findings
Among the many important findings uncovered are: the most effective way to drive all positive WOM behaviors is through maximizing affective commitment and positive emotions; minimizing negative emotions and ensuring that customers are satisfied lowers all negative WOM behaviors; all other attitudinal drivers have lower or even mixed effects on the different WOM behaviors; and customer characteristics can have a surprisingly large impact on how attitudes affect different WOM behaviors.

Practical implications
These findings have important managerial implications for promotion (which attitudes should be stimulated to produce the desired WOM behavior) and segmentation (how should marketing efforts change, based on segments defined by customer characteristics).

Originality/value
This research points to the myriad of factors that enhance positive and reduce negative word-of-mouth, and the importance of accounting for customer heterogeneity in assessing the likely impact of attitudinal drivers on word-of-mouth behaviors.
Customer engagement behaviours in social media: capturing innovation opportunities
Authors: Carlson Jamie , Rahman Mohammad , Voola Ranjit , De Vries Natalie 
Published: January 2018

Purpose
Social media brand pages have become instrumental in enabling customers to voluntarily participate in providing feedback/ideas for improvement and collaboration with others that contribute to the innovation effort of brands. However, research on mechanisms which harness these specific customer engagement behaviours (CEB) in branded social media platforms is limited. Based on the stimulus–organism–response paradigm, this study investigates how specific online-service design characteristics in social media brand pages induce customer-perceived value perceptions, which in turn, stimulate feedback and collaboration intentions with customers.

Design/methodology/approach
Data collected from 654 US consumers of brand pages on Facebook were used to empirically test the proposed framework via structural equation modelling.

Findings
The theoretical framework found support for most hypothesized relationships showing how online-service design characteristics induce an identified set of customer value perceptions that influence customer feedback and collaboration intentions.

Research limitations/implications
The sample is restricted to customer evaluations of brand pages on Facebook in the USA. Practitioners are advised to maximize online-service design characteristics of content quality, brand page interactivity, sociability and customer contact quality as stimulants that induce brand learning value, entitativity value and hedonic value. This then translates to customer feedback and collaboration intentions towards the brand page.

Originality/value
The findings have important implications for the design and optimization of online services in the customer engagement-innovation interface to harness CEBs for innovation performance.
Preparation and properties of polyimide/Fe3O4 composite foams
Authors: Weng Ling , Wang Ting , Ju Pei-Hai , Liu Li-Zhu 
Published: January 2018

Purpose
This paper aims to develope the electromagnetic interference shielding materials with high performance. To develop advanced polymer-based electromagnetic interference shielding materials with rather high temperature stability, good processability and moderate mechanical properties, the authors chose the polyimide (PI) foam as matrix and ferriferrous oxide (Fe3O4) as fillers to prepare the composite foams with lightweight and rather good electromagnetic interference shielding performance.

Design/methodology/approach
Some polyimide nanocomposite foams with Fe3O4 as fillers have been prepared by in situ dispersion and foaming with pyromellitic dianhydride (PMDA) and isocyanate (PAPI) as raw materials and water as foaming agent. By varying the Fe3O4 contents, a series of PI/Fe3O4 nanocomposite foams with fine microstructures and high thermal stability were obtained. The structure and performances of nanocomposite foams were examined, and the effects of Fe3O4 on the microstructure and properties of composite foams were investigated.

Findings
This work demonstrates that PI/Fe3O4 foams could be fabricated by thermally treating the polyimide foam intermediates with Fe3O4 nanoparticles through a blending reaction of precursors. The final PI/Fe3O4 composite foams maintained the excellent thermal property and showed a super paramagnetic behaviour, which has a positive effect on the improvement of electromagnetic shielding performance.

Research limitations/implications
In this paper, the effects of Fe3O4 on the performances of PI/Fe3O4 composite foam were reported. It provided an effective methodology for the preparation of polymer/Fe3O4 nanocomposite foams, which hold great promise towards the potential application in the areas of electromagnetic shielding materials.

Originality/value
A series of PI/Fe3O4 composite foams with different contents of Fe3O4 were prepared by blending reaction of the precursors. The effects of Fe3O4 on the structures and properties of PI/Fe3O4 composite foam were discussed in detail.
Synthesis of polyurethane dispersion from polyesteramide polyol
Authors: More Aarti P. , Mhaske Shashank T. 
Published: January 2018

Purpose
The study aims to synthesise polyurethane dispersion from polyesteramide polyol. The polyesteramide polyol is a novel polyol for the synthesis of polyurethane dispersion.

Design/methodology/approach
Polyesteramide polyol has been synthesised from phthalic anhydride and fatty amide of mustard oil. Aminolysis of mustard oil had been carried out with diethanolamine. The novel polyurethane dispersion had been synthesised using a polyesteramide polyol as a precursor. Isophorone diisocyanate was used as an isocyanate component and polyurethane dispersion (PUDs) had been synthesised by an anionic method where DMPA was introduced to introduce –COOH groups as via grafting to the resin backbone. Triethylamine was used for neutralisation and, hence, for further dispersion in water. Hydroxyl ethyl methacrylate was used for the synthesis to introduce unsaturation in the backbone of PUDs. The coating was made by an UV curing process. The coating was characterised for mechanical properties, chemical properties, thermal properties as well as stain resistance.

Findings
The polyurethane dispersion formed through it has ester and amide linkage present in it. The acetone process is used for its synthesis. The nuclear magnetic resonance spectroscopy confirms the successful formation of polyesteramide polyol and PUDs. Even though long aliphatic chains present in polyol which may impart hydrophobicity the synthesis PUDs well dispersed in water. It is observed as the coating made from it have hardness and scratch resistance properties. The coating also exhibits good stain resistance properties.

Practical implications
The method is an easy one to synthesise polyurethane dispersion from polyesteramide polyol, which is based on ester and amide linkage.

Originality/value
To the best of the authors’ knowledge, this is the first report on synthesised polyurethane dispersion from polyesteramide polyol. The polyesteramide resin already proves its excellence and upcoming technology in the coating industry. Here, they are incorporated into the synthesis of polyurethane dispersion.
Pre-concentration and determination of fluorescence quenching of CdS quantum dots of Pb ions by dispersive liquid–liquid microextraction in the presence of the ionic liquids
Authors: Jafarnejad Ehsan , Abolhasani Jafar , Derakhshan Arezoo 
Published: January 2018

Purpose
This study aims to develop a new simple and sensitive method for the microextraction of trace levels of lead in environmental samples. It is based on the use of ionic liquids based dispersive liquid–liquid microextraction (IL–DLLME) before spectrofluorometry.

Design/methodology/approach
Cadmium sulphide quantum dots have been synthesised using thioglycolic acid as capping agent through a one-step process with stability and excellent water-solubility, and have strong affinity for lead (Pb). This probe is based on the fluorescence quenching effect of functionalised cadmium sulphide quantum dots.

Findings
Factors affecting the extraction efficiency and fluorescence quenching of metals, such as the amount of ionic liquid, amount of metanol, microextraction and centrifugation time, volume of quantum dots and buffer pH, were investigated. Under optimum conditions, the calibration graph was linear in the range of 0.01-3 µg.L-1, with the detection limit of 0.004 µg.L-1 for Pb2+. The relative standard deviation (RSD%, n = 5) of 5.4 per cent at 1 µg.L-1 of Pb2+ was obtained.

Originality/value
This method for pre-concentration of the Pb ions by dispersive liquid–liquid microextraction is novel and could be used for various applications in the synthesis of a wide variety of determination of fluorescence quenching of cadmium sulphide quantum dots.
Fabrication of renewable myristic acid based polyurethane nano zinc phosphate hybrid coatings to mitigate corrosion of mild steel
Authors: Rajput Sandip D. , Patil Chandrashekhar K. , Gite Vikas V. 
Published: January 2018

Purpose
The present study aims to demonstrate the use of renewable source in the preparation of polyurethane (PU) coatings and mitigation of corrosion of mild steel using nano zinc phosphate. Results indicated improvement in the properties of the PU coatings, especially anticorrosive properties by the addition of nano zinc phosphate.

Design/methodology/approach
Renewable-source-based polyestermyristamide polyol was synthesized using myristic acid as a starting material. The synthesis of polyol was carried by amidation as well as by esterification by a one-pot route. The structure of the prepared polyestermyristamide was confirmed with the support of end-group analysis and spectral study. PU coatings were prepared from synthesized polyestermyristamide polyol and used to protect metal substrate against corrosion. Corrosion properties of the prepared PU were found to be lower; hence, to improve the performance of these coatings, nano zinc phosphate was added to the coatings. The nano zinc phosphate was synthesized in the laboratory by reported sonication method and analyzed for morphology by scanning electron microscopy. Performance of coatings was studied with respect to effect of percentage nano zinc phosphate on thermal stability, mechanical properties and chemical resistances of PU coatings.

Findings
The combination of zinc phosphate nano rods and particles in myristic acid-based PU coatings provided substantial corrosion barrier properties to the coatings. Different per cent of the synthesized zinc phosphate nano rods and particles were loaded into the matrix, and corresponding coatings were estimated for corrosion resistance, thermal and chemical properties. Immersion study of the coated panels in 3.5 per cent NaCl solution showed good corrosion resistance for both PU coatings containing 2 and 3 per cent nano zinc phosphate.

Practical implications
This paper has provided the solution to replace existing petroleum-based raw materials with myristic acid as a renewable source in preparing PU coatings. Conventional coatings act as physical barriers against aggressive species but do not have ability to perform as permanent impassable to corrosive species. Hence, nano-sized zinc phosphate is used as corrosion inhibitor in to the synthesized PU coatings for enhancing anticorrosive performance.

Originality/value
In the paper, polyesteramide polyol is synthesized using renewable-source-based material, i.e. myristic acid to replace existing petroleum-based acid as a greener approach. Normally, vegetable oils are preferred as they have such kinds of polyols. The polyesteramide reaction is one pot that avoids the extra steps required in the synthesis. Further, it has been found that the pristine renewable coatings are unable to fully protect subtract from corrosion, whereas an addition of the nano-size zinc phosphate has enhanced the corrosion properties of the coatings.
Design, development and performance evaluation of pressure sensor using eddy current displacement sensing coil
Authors: K. Gobi , B. Kannapiran , D. Devaraj , K. Valarmathi 
Published: January 2018

Purpose
The conventional strain gauge type pressure sensor suffers in static testing of engines due to the contact transduction method. This paper aims to focus on the concept of non-contact transduction-based pressure sensor using eddy current displacement sensing coil (ECDS) to overcome the temperature limitations of the strain gauge type pressure sensor. This paper includes the fabrication of prototypes of the proposed pressure sensor and its performance evaluation by static calibration. The fabricated pressure sensor is proposed to measure pressure in static test environment for a short period in the order of few seconds. The limitations of the fabricated pressure sensor related to temperature problems are highlighted and the suitable design changes are recommended to aid the future design.

Design/methodology/approach
The design of ECDS-based pressure sensor is aimed to provide non-contact transduction to overcome the limitations of the strain gauge type of pressure sensor. The ECDS is designed and fabricated with two configurations to measure deflection of the diaphragm corresponding to the applied pressure. The fabricated ECDS is calibrated using a standard micro meter to ensure transduction within limits. The fabricated prototypes of pressure sensors are calibrated using dead weight tester, and the calibration results are analyzed to select the best configuration. The proposed pressure sensor is tested at different temperatures, and the test results are analyzed to provide recommendations to overcome the shortcomings.

Findings
The performance of the different configurations of the pressure sensor using ECDS is evaluated using the calibration data. The analysis of the calibration results indicates that the pressure sensor using ECDS (coil-B) with the diaphragm as target is the best configuration. The accuracy of the fabricated pressure sensor with best configuration is ±2.8 per cent and the full scale (FS) output is 3.8 KHz. The designed non-contact transduction method extends the operating temperature of the pressure sensor up to 150°C with the specified accuracy for the short period.

Originality/value
Most studies of eddy current sensing coil focus on the displacement and position measurement but not on the pressure measurement. This paper is concerned with the design of the pressure sensor using ECDS to realize the non-contact transduction to overcome the limitations of strain gauge type pressure sensors and evaluation of the fabricated prototypes. It is shown that the accuracy of the proposed pressure sensor is not affected by the high temperature for the short period due to non-contact transduction using ECDS.
Comparative Transcriptome Analysis Reveals the Mechanism Underlying 3,5-Dibromo-4-Hydroxybenzoate Catabolism via a New Oxidative Decarboxylation Pathway
Authors: Chen Kai , Mu Yang , Jian Shanshan , Zang Xiaoxia , Chen Qing , Jia Weibin , Ke Zhuang , Gao Yanzheng , Jiang Jiandong 
Published: January 2018

ABSTRACT

The compound 3,5-dibromo-4-hydroxybenzoate (DBHB) is both anthropogenically released into and naturally produced in the environment, and its environmental fate is of great concern. Aerobic and anaerobic reductive dehalogenations are the only two reported pathways for DBHB catabolism. In this study, a new oxidative decarboxylation pathway for DBHB catabolism was identified in a DBHB-utilizing strain,
Pigmentiphaga
sp. strain H8. The genetic determinants underlying this pathway were elucidated based on comparative transcriptome analysis and subsequent experimental validation. A gene cluster comprising
orf420
to
orf426
, with transcripts that were about 33- to 4,400-fold upregulated in DBHB-induced cells compared with those in uninduced cells, was suspected to be involved in DBHB catabolism. The gene
odcA
(
orf420
), which is essential for the initial catabolism of DBHB, encodes a novel NAD(P)H-dependent flavin monooxygenase that mediates the oxidative decarboxylation of DBHB to 2,6-dibromohydroquinone (2,6-DBHQ). The substrate specificity of the purified OdcA indicated that the 4-hydroxyl group and its
ortho
-halogen(s) are important for hydroxylation of the C-1 site carboxyl group by OdcA. 2,6-DBHQ is then ring cleaved by the dioxygenase OdcB (Orf425) to 2-bromomaleylacetate, which is finally transformed to β-ketoadipate by the maleylacetate reductase OdcC (Orf426). These results provide a better understanding of the molecular mechanism underlying the catabolic diversity of halogenated
para
-hydroxybenzoates.

IMPORTANCE
Halogenated hydroxybenzoates (HBs), which are widely used synthetic precursors for chemical products and common metabolic intermediates from halogenated aromatics, exert considerable adverse effects on human health and ecological security. Microbial catabolism plays key roles in the dissipation of halogenated HBs in the environment. In this study, the discovery of a new catabolic pathway for 3,5-dibromo-4-hydroxybenzoate (DBHB) and clarification of the genetic determinants underlying the pathway broaden our knowledge of the catabolic diversity of halogenated HBs in microorganisms. Furthermore, the NAD(P)H-dependent flavin monooxygenase OdcA identified in
Pigmentiphaga
sp. strain H8 represents a novel 1-monooxygenase for halogenated
para
-HBs found in prokaryotes and enhances our knowledge of the decarboxylative hydroxylation of (halogenated)
para
-HBs.
Contribution of YthA, a PspC Family Transcriptional Regulator of Lactococcus lactis F44 Acid Tolerance and Nisin Yield: a Transcriptomic Approach
Authors: Wu Hao , Liu Jingui , Miao Sen , Zhao Yue , Zhu Hongji , Qiao Mingqiang , Saris Per Erik Joakim , Qiao Jianjun 
Published: January 2018

ABSTRACT

To overcome the adverse impacts of environmental stresses during growth, different adaptive regulation mechanisms can be activated in
Lactococcus lactis
. In this study, the transcription levels of eight transcriptional regulators of
L. lactis
subsp.
lactis
F44 under acid stress were analyzed using quantitative reverse transcription-PCR. Eight gene-overexpressing strains were then constructed to examine their influences on acid-resistant capability. Overexpressing
ythA
, a PspC family transcriptional regulator, increased the survival rate by 3.2-fold compared to the control at the lethal pH 3.0 acid shock. Moreover, the nisin yield was increased by 45.50%. The
ythA
-overexpressing strain FythA appeared to have higher intracellular pH stability and nisin-resistant ability. Subsequently, transcriptome analysis revealed that the vast majority of genes associated with amino acid biosynthesis, including arginine, serine, phenylalanine, and tyrosine, were predominantly upregulated in FythA. Arginine biosynthesis (
argG
and
argH
), arginine deiminase pathway, and polar amino acid transport (
ysfE
and
ysfF
) were proposed to be the main regulation mechanisms of YthA. Furthermore, the transcription of genes associated with pyrimidine and exopolysaccharide biosynthesis were upregulated. The transcriptional levels of
nisIPRKFEG
genes were substantially higher in FythA, which directly contributed to the yield and resistance of nisin. Three potential DNA-binding sequences were predicted by computer analysis using the upstream regions of genes with prominent changes. This study showed that YthA could increase acid resistance and nisin yield and revealed a putative regulation mechanism of YthA.

IMPORTANCE
Nisin, produced by
Lactococcus lactis
subsp.
lactis
, is widely used as a safe food preservative. Acid stress becomes the primary restrictive factor of cell growth and nisin yield. In this research, we found that the transcriptional regulator YthA was conducive to enhancing the acid resistance of
L. lactis
F44. Overexpressing
ythA
could significantly improve the survival rate and nisin yield. The stability of intracellular pH and nisin resistance were also increased. Transcriptome analysis showed that nisin immunity and the biosynthesis of some amino acids, pyrimidine, and exopolysaccharides were enhanced in the engineered strain. This study elucidates the regulation mechanism of YthA and provides a novel strategy for constructing robust industrial
L. lactis
strains.