Abstract
Purpose
The purpose of this paper is mainly to know: (1) the sound absorption coefficient of porous composite structures constituted by a new kind of lightweight ceramic foam and perforated plate; (2) the availability of an equivalent porous material model, recently proposed by the present author, to these composite structures in sound absorption.
Design/methodology/approach
A kind of lightweight ceramic foam with bulk density of 0.38–0.56 g·cm-3 was produced by means of molding, drying and sintering. The effect of stainless steel perforated plate on sound absorption performance of the ceramic foam was investigated by means of JTZB absorption tester.
Findings
The results indicate that the sound absorption performance could be obviously changed by adding the stainless steel perforated plate in front of the porous samples and the air gap in back of the porous samples. Adding the perforated plate to the porous sample with a relatively large pore size, the sound absorption performance could be evidently improved for the composite structure. When the air gap is added to the composite structure, the first absorption peak shifts to the lower frequency, and the sound absorption coefficient could increase in the low frequency range.
Originality/value
Based on the equivalent porous material model and the “perforated plate with air gap” model, the sound absorption performance of the composite structures can be simulated conveniently to a great extent by using Johnson-Champoux-Allard model.
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Ajay Kumar Singal and Faisal Mohammad Ahsan
Emerging economy firms seek strategic assets through cross-border acquisitions (CBAs) to upgrade their capabilities. The paper explores the relation between emerging economy…
Abstract
Purpose
Emerging economy firms seek strategic assets through cross-border acquisitions (CBAs) to upgrade their capabilities. The paper explores the relation between emerging economy firms' investments in CBAs and subsequent investments in domestic R&D. It investigates the underlying mechanism that links a firm's decision to pursue CBAs and the outcomes from the CBAs. The main idea behind the study is that firms have higher possibility of creating value from cross-border acquisitions when they simultaneously invest in domestic R&D though both investments are constrained by financial and managerial resources.
Design/methodology/approach
The hypotheses are tested on a panel data set of 296 Indian firms over a period of 13 years (2003–2015). The authors use a two-stage Heckman procedure for testing their hypotheses. In the first stage, a probit model predicts the probability of a firm being a cross-border acquirer. The second stage model is estimated by a pooled-data GLS (generalized least squares) regression technique.
Findings
The authors find a nonlinear (inverted U-shaped) relationship between firm's investments in CBAs and domestic R&D. This suggests a complementary relation between investments in CBAs and a firm's domestic R&D at lower levels of investments in CBAs. At higher levels of investments in CBAs, CBA investments begin to substitute for firm's domestic R&D investments. For firms with higher international product-market experience and those operating in the hi-tech industry, the relationship between investments in CBAs and domestic R&D is complementary even at higher levels of CBA investments.
Originality/value
The study highlights the role of an emerging market firm's investment in domestic R&D as a link between the decision to invest in CBAs and related outcomes thereof. Emerging market firms face resource constraints while pursuing simultaneous investments in CBAs and R&D, but investment in R&D is essential for realizing the acquisition objectives. The authors also establish the significance of industry context and experiential learning in deciding the allocation of resources between CBAs and internal R&D.
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Donghua Zhao, Weizhong Guo, Baibing Zhang and Feng Gao
This paper aims to investigate the circulation of moist silica sand to provide appropriate feeding modes and references for designing the coating device when printing sand mold…
Abstract
Purpose
This paper aims to investigate the circulation of moist silica sand to provide appropriate feeding modes and references for designing the coating device when printing sand mold with line-forming.
Design/methodology/approach
First, this paper briefly introduces sand mold printing with line-forming and the circulation problem brought by moist silica sand. The outlet may be choked due to poor flowability and solidification characteristic, resulting in poor dimensional tolerance and even production failure. Then, based on circulation modeling, a series of feeding modes is proposed to guarantee adequate feeding, avoid solidification and ensure successful fabrication. Finally, the GUI of control software is developed, including slicing, path planning and the function of virtual printing.
Findings
Several feeding modes of moist silica sand are put forward to avoid the choke.
Research limitations/implications
The authors will further investigate the flowability of furan no-bake sand based on experiments.
Originality/value
This paper is going to provide references for the novel design of nozzle, prototype and sand mold printing, influencing significantly on mold manufacturing and the casting industry. This research applies equally to equipment having the circulation of high moist particles with solidification features.
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Yingying Chi, Lianghua Chen, Yufei Hu, Yafei Zu, Xue Peng and Jinpei Liu
Green technology, characterized by its environmentally friendly attributes and sustainable practices, has emerged as a crucial tool in harmonizing the economic and ecological…
Abstract
Purpose
Green technology, characterized by its environmentally friendly attributes and sustainable practices, has emerged as a crucial tool in harmonizing the economic and ecological benefits. However, the challenge lies in selecting the most effective strategies for acquiring green technology. This paper aims to explore how chemical enterprises choose green technology acquisition strategies across diverse scenarios.
Design/methodology/approach
Considering the influence of competition effects, spillover effects and their interactions on selecting green technology acquisition strategies, this paper develops three decision models (independent R&D, cooperative R&D and technology introduction). Drawing on the duopoly game theory as its theoretical framework, this paper delves into the examination of the economic and environmental benefits within distinct scenarios.
Findings
Cooperative R&D excels in promoting green technology R&D when spillover effects are strong, while independent R&D demonstrates superiority when spillover effects are weak. The threshold for the strength of spillover effects is related to competition effects. Additionally, cooperative R&D typically yields greater financial advantages than independent R&D and technology introduction. Moreover, the economic and environmental benefits may not be optimized simultaneously. Only enterprises that satisfy low competition and spillover effects as well as high competition and spillover effects, can achieve win-win economic and environmental benefits.
Originality/value
Although green technology R&D and introduction are alternative strategies, they have typically been considered separately in prior literature. This study attempts to incorporate green technology R&D and introduction into a strategic system to investigate the selection of green technology acquisition strategies, taking into account competition effects, spillover effects and their interactions.
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David J. Thompson, Dong Zhao, Evangelos Ntotsios, Giacomo Squicciarini, Ester Cierco and Erwin Jansen
The vibration of the rails is a significant source of railway rolling noise, often forming the dominant component of noise in the important frequency region between 400 and…
Abstract
Purpose
The vibration of the rails is a significant source of railway rolling noise, often forming the dominant component of noise in the important frequency region between 400 and 2000 Hz. The purpose of the paper is to investigate the influence of the ground profile and the presence of the train body on the sound radiation from the rail.
Design/methodology/approach
Two-dimensional boundary element calculations are used, in which the rail vibration is the source. The ground profile and various different shapes of train body are introduced in the model, and results are observed in terms of sound power and sound pressure. Comparisons are also made with vibro-acoustic measurements performed with and without a train present.
Findings
The sound radiated by the rail in the absence of the train body is strongly attenuated by shielding due to the ballast shoulder. When the train body is present, the sound from the vertical rail motion is reflected back down toward the track where it is partly absorbed by the ballast. Nevertheless, the sound pressure at the trackside is increased by typically 0–5 dB. For the lateral vibration of the rail, the effects are much smaller. Once the sound power is known, the sound pressure with the train present can be approximated reasonably well with simple line source directivities.
Originality/value
Numerical models used to predict the sound radiation from railway rails have generally neglected the influence of the ground profile and reflections from the underside of the train body on the sound power and directivity of the rail. These effects are studied in a systematic way including comparisons with measurements.
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Feiwu Ren, Yi Huang, Zihan Xia, Xiangyun Xu, Xin Li, Jiangtao Chi, Jiaying Li, Yanwei Wang and Jinbo Song
To address challenges such as inadequate funding and inefficiency in public infrastructure construction, PPPs have gained significant global traction. This study aims to…
Abstract
Purpose
To address challenges such as inadequate funding and inefficiency in public infrastructure construction, PPPs have gained significant global traction. This study aims to comprehensively assess the impacts and mechanisms of PPPs on the SDI and to provide rational policy recommendations based on the findings.
Design/methodology/approach
We collated a dataset from 30 Chinese provinces covering the years 2005–2020 as our research sample. The study’s hypotheses are tested using a double fixed-effects model, a chained mediated-effects model and a multidimensional heterogeneity analysis.
Findings
Our findings indicate that PPPs have a facilitating effect on SDI in general. This boost usually lags behind policy implementation and is cyclical in the time dimension. In the spatial dimension, PPPs contribute significantly to SDI in the eastern and western regions, but not in the central region. From the perspective of the dynamics of economic, social and industrial development, PPPs in economically backward areas are difficult to promote SDI, promote it the most in economically medium regions and are slightly less in economically developed regions than in medium regions. This promotion effect has an inverted U-shaped relationship with social development and diminishes with industrial structure upgrading. Finally, due to the negative relationship between PPPs and social development and between social development and SDI, PPPs are shown to contribute to SDI and are identified as critical paths. However, PPPs suppress SDI by inhibiting economic and industrial development.
Originality/value
This study makes three novel contributions to the existing body of knowledge: (1) we innovatively introduce the United Nations Sustainable Development Goals (SDGs) into the field of infrastructure research, offering fresh perspectives on SDI enhancement; (2) revealing the mechanisms by which PPPs affect SDI through the three dimensions of economic, social and industrial development enabling policymakers to better understand and optimize resource allocation and improve planning, design and management of PPP projects for sustainable infrastructure and (3) we assess the spatiotemporal variances of PPPs’ effects on SDI and the diversity across regions at different social, economic and industrial structures developmental stages, offering critical insights to global decision-makers to devise tailored policy measures.
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Abstract
Purpose
The purpose of this study is to investigate the inhibition efficiency and mechanism of a specific carboxylate corrosion inhibitor which consists of benzoic acid and dimethylethanolamine on steel surface.
Design/methodology/approach
The performance of carbon steel influenced by this organic inhibitor under different concentration of Cl− and immersion time was studied by linear polarization resistance and electrochemical impedance spectroscopy in a simulated concrete pore (SCP) solution. The surface morphology and composition of steel was also analyzed by optical microscopy, SEM and EDS to investigate the effect of inhibitor on the pattern of the steel surface after long-term immersion.
Findings
Carboxylate of benzoic acid and dimethylethanolamine can increase the chloride threshold level and decrease the corrosion area of carbon steel in SCP solution with 0.6 mol/L Cl− even after 120 days exposure. The inhibition mechanism of inhibitor lies in quick adsorption and buffering effect at initial time then formed deposited layer on steel surface after long-term immersion in chloride-rich environment.
Originality/value
It demonstrated that the carboxylate corrosion inhibitor not only can improve the chloride threshold level for carbon steel but also effectively decrease the corrosion rate even in chloride-rich SCP solution after long-term immersion, which is different form the conventional amino alcohol.
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The ELINOR electronic library system is a well integrated, fully functioning system implemented at De Montfort University in 1993. The system currently contains the full contents…
Abstract
The ELINOR electronic library system is a well integrated, fully functioning system implemented at De Montfort University in 1993. The system currently contains the full contents of some 35 000‐page course materials assisting the teaching and learning of one undergraduate course. The core software for the system is PixTex/EFS, a free text retrieval system with well integrated imaging functions. A usage statistics collection and management subsystem and a printing control subsystem were developed in‐house later for copyright management and other management purposes. This paper presents the various aspects of the ELINOR electronic library system including its database, browsing, searching, printing, document capturing, managing, architecture, the user aspect, and the pros and cons of the system.
Wenyan Xu, Qiran Zhao, Wei Si and Chen Zhu
While the adverse health consequences of obesity are well-documented, the causal effect between obesity and economic outcomes, particularly individual income in the labor market…
Abstract
Purpose
While the adverse health consequences of obesity are well-documented, the causal effect between obesity and economic outcomes, particularly individual income in the labor market, has yielded inconsistent findings. At the same time, China has the highest number of obese or overweight people around the world in recent years. However, limited research has examined the causal effect of obesity on Chinese rural residents’ income. To answer this question, our study aims to identify the causal impact of obesity on Chinese rural residents.
Design/methodology/approach
First, we conduct ordinary least squares, instrumental variable and Mendelian randomization methods to evaluate the impact of obesity on Chinese rural residents’ income. Then, we employ quantile regression and instrumental variable quantile regression to investigate the potential distributional impacts of obesity across various income segments. For the generality of our results, we also use 485,849 samples from the UK Biobank and the two-sample Mendelian randomization method to analyze.
Findings
Our one-sample Mendelian randomization analysis, based on a sample of 441 people collected from rural China in 2019 and 2021, revealed that obesity reduced residents’ annual income by 647.87 China Yuan. Results from the UK further support our findings. We also find that the adverse causal impact of obesity on income is significant in individuals within the above 50th percentile of the income distribution. Additionally, childhood obesity has a long-term adverse effect on income in adulthood.
Research limitations/implications
These results contribute to a more nuanced understanding of the economic costs of obesity. Weight penalties may lead to a deviation from the efficiency that should be pursued in the labor market and widen income disparity.
Originality/value
We provide novel and robust instrumental variables and utilize the Mendelian randomization method to analyze the effect of obesity on Chinese rural residents.