Shahriar Abubakri, Pritpal S. Mangat, Konstantinos Grigoriadis and Vincenzo Starinieri
Microwave curing (MC) can facilitate rapid concrete repair in cold climates without using conventional accelerated curing technologies which are environmentally unsustainable…
Abstract
Purpose
Microwave curing (MC) can facilitate rapid concrete repair in cold climates without using conventional accelerated curing technologies which are environmentally unsustainable. Accelerated curing of concrete under MC can contribute to the decarbonisation of the environment and provide economies in construction in several ways such as reducing construction time, energy efficiency, lower cement content, lower carbonation risk and reducing emissions from equipment.
Design/methodology/approach
The paper investigates moisture loss and pore properties of six cement-based proprietary concrete repair materials subjected to MC. The impact of MC on these properties is critically important for its successful implementation in practice and current literature lacks this information. Specimens were microwave cured for 40–45 min to surface temperatures between 39.9 and 44.1 °C. The fast-setting repair material was microwave cured for 15 min to 40.7 °C. MC causes a higher water loss which shows the importance of preventing drying during MC and the following 24 h.
Findings
Portland cement-based normal density repair mortars, including materials incorporating pfa and polymer latex, benefit from the thermal effect of MC on hydration, resulting in up to 24% reduction in porosity relative to normal curing. Low density and flowing repair materials suffer an increase in porosity up to 16% due to MC. The moisture loss at the end of MC and after 24h is related to the mix water content and porosity, respectively.
Originality/value
The research on the application of MC for rapid repair of concrete is original. The research was funded by the European commission following a very rigorous and competitive review process which ensured its originality. Original data on the parameters of porosity and moisture loss under MC are provided for different generic cementitious repair materials which have not been studied before. Application of MC to concrete construction especially in cold climates will provide environmental, economic and energy benefits.
Details
Keywords
Moinak Maiti and A. Balakrishnan
The purpose of this paper is to focus on one of the major emerging Asian economies – India – to examine the role of human capital in asset prices.
Abstract
Purpose
The purpose of this paper is to focus on one of the major emerging Asian economies – India – to examine the role of human capital in asset prices.
Design/methodology/approach
The analysis uses various statistical techniques (e.g. multifactor regression model, 3D graphs, GRS test and residual graphs) to test the role of human capital in asset prices.
Findings
A six-factor model designed for capturing the size, value, profitability, investment and human capital patterns in average portfolio returns performs better than both Fama–French’s (1993) three- and Fama–French’s (2015) five-factor model. The main problem of six-factor model is its failure in capturing the average returns on “microcap with low-value stocks that are highly profitable invests aggressively for asset growth but invests much lesser for human growth” and “microcap with unprofitable stocks whose returns behave like those of low-value firms with conservative investment”. The study finds the investment factor (CMA) of Fama–French’s (2015) five-factor model as the redundant factor for describing the portfolio average returns in the study sample.
Research limitations/implications
The paper argues that human capital also plays a role in predicting returns. This has significant public policy content.
Originality/value
The present study is novel for several reasons: first, it includes six-factor model descriptions; second, no comprehensive asset pricing study is done with human capital in Asian emerging markets, especially in India. Perhaps, this is the first study to examine whether portfolio returns are affected by the human capital in the Indian context. Third, the study period and methodology used are completely different from the previous studies.
Details
Keywords
Mingkang Zhang, Yongqiang Yang, Meizhen Xu, Jie Chen and Di Wang
The purpose of this study is focused on the mechanical properties of multi-materials porous structures manufactured by selective laser melting (SLM).
Abstract
Purpose
The purpose of this study is focused on the mechanical properties of multi-materials porous structures manufactured by selective laser melting (SLM).
Design/methodology/approach
The Diamond structure was designed by the triply periodic minimal surface function in MATLAB, and multi-materials porous structures were manufactured by SLM. Compression tests were applied to analyze the anisotropy of mechanical properties of multi-materials porous structures.
Findings
Compression results show that the multi-materials porous structure has a strong anisotropy behavior. When the compression force direction is parallel to the material arrangement, multi-materials porous structure was compressed in a layer-by-layer way, which is the traditional deformation of the gradient structure. However, when the compression force direction is perpendicular to the material arrangement, the compression curves show a near-periodic saw-tooth waveform characteristic, and this kind of structure was compressed consistently. It is demonstrated that the combination with high strength brittle material and low strength plastic material improves compression mode, and plastic material plays a role in buffering fracture.
Originality/value
This research provides a new method for the design and manufacturing of multi-materials porous structures and an approach to change the compression behavior of the porous structure.
Details
Keywords
Adriano C. Lisboa, Rodney R. Saldanha, Renato C. Mesquita and Ricardo H.C. Takahashi
The purpose of this paper is to investigate the extension of Delaunay refinement algorithms to work directly with a curved geometry in arbitrary dimensional spaces, which is also…
Abstract
Purpose
The purpose of this paper is to investigate the extension of Delaunay refinement algorithms to work directly with a curved geometry in arbitrary dimensional spaces, which is also able to refine geometry pieces of different dimensions altogether.
Design/methodology/approach
The extension of Delaunay refinement is based on ideas of the Bowyer‐Watson algorithm and Ruppert algorithm.
Findings
The attempt to extend the fundamental ideas of Delaunay refinement to cope with curved geometries led to an algorithm whose performance in practice, regarding speed and mesh quality, is comparable to classical Delaunay refinement for flat geometries. Unfortunately, there are only theoretical guarantees that the refinement itself works under some conditions. No theoretical mesh quality bounds are provided.
Research limitations/implications
A mesh refinement algorithm that deals with curved geometries is a key feature for adaptive mesh generators, so that points are inserted properly in the curved pieces instead of in linear approximations of them. For instance, it is well known that sharp edges are singular points of finite element formulations. This singularity fulfills in practice as mesh is refined around them. Those corners can be rounded up to avoid singularities. Furthermore, with this kind of tool, for instance, a user could start to mesh a disc from a single triangle representing it. Points would be efficiently inserted in the circle as needed during refinement.
Originality/value
This paper introduces the concept of manifold complex and also an extension of Delaunay refinement algorithm to deal with curved geometries.
Details
Keywords
Piezoelectric ceramics are often combined with other materials to fabricate composites, which are used for constructions of intelligent systems. This paper is concerned with the…
Abstract
Piezoelectric ceramics are often combined with other materials to fabricate composites, which are used for constructions of intelligent systems. This paper is concerned with the fracture of a piezoelectric fiber embedded in an elastic matrix of finite radius. The fiber composite medium is subjected to the axially symmetric mechanical and electrical loads. Fourier and Hankel transforms are used to reduce the problem to the solution of a system of integral equations. Numerical solutions for the crack tip fields are obtained for various crack sizes and different piezoelectric fiber volume fractions. Both impermeable and permeable crack‐face electrical boundary conditions are considered. Applicability and effect of the crack‐face electrical boundary conditions are discussed.
Details
Keywords
Vanessa P. Dennen, Lauren M. Bagdy and Hilal Ayan Karabatman
This study aims to explore the use and perceptions of social media among university students before and during their transition from high school to higher education.
Abstract
Purpose
This study aims to explore the use and perceptions of social media among university students before and during their transition from high school to higher education.
Design/methodology/approach
This exploratory, cross-sectional study uses an online survey of 312 undergraduate students at a large public research university in the USA.
Findings
Active participation was prevalent for connecting with peers, while passive use was high when learning about university-related topics. While at university, social media was most useful for finding campus events and connecting with classmates, but least effective for connecting with instructors. Most participants experienced meaningful change in their social media use from high school to university, which is often attributed to personal growth. Social media intensity correlated weakly but positively with usefulness and sense of belonging.
Research limitations/implications
The study’s sample from a single university limits generalizability. While similar institutions might show comparable results, variations due to student demographics and differing institutional practices could emerge. The retrospective approach for reporting high school behaviors also poses a limitation. Future research could longitudinally follow students from university search to enrollment and attendance.
Practical implications
The study recommends universities adjust social media strategies by prioritizing social content, using student ambassadors and customizing feeds. Universities should support students both online and offline, recognizing diverse pathways to belonging.
Originality/value
This study examines the transition period by asking university students to retrospectively reflect on high school experiences and also report current experiences. It also offers insights into student perceptions of whether their social media use has changed in meaningful ways.
Details
Keywords
Thomas Wright, Imran Hyder, Mitchell Daniels, David Kim and John P. Parmigiani
The purpose of this paper is to determine which of the ten material properties of the Hashin progressive damage model significantly affect the maximum load-carrying ability of…
Abstract
Purpose
The purpose of this paper is to determine which of the ten material properties of the Hashin progressive damage model significantly affect the maximum load-carrying ability of center-notched carbon fiber panels under in-plane tension and out-of-plane bending.
Design/methodology/approach
The approach used is to calculate the maximum load using a finite element model for a range of material property values as specified by a fraction factorial design. The finite element model used has been experimentally validated in prior work.
Findings
Results showed that for the laminates considered, at most three and as few as one of the ten Hashin material properties significantly affected the magnitude of the maximum load.
Practical implications
While the results of this paper only specifically apply to the laminates included in the study, the results suggest that, in general, only a small number of the Hashin material properties affect laminate load-carrying ability.
Originality/value
Knowing which properties are significant is of value in selecting materials to optimize performance and also in determining which properties need to be known to a high accuracy.
Details
Keywords
Fan‐Hua Kung and Cheng Li Huang
The purpose of this paper is to investigate the influence of moral philosophy on the ethical beliefs of auditors. The paper argues that an individual's moral philosophy is the key…
Abstract
Purpose
The purpose of this paper is to investigate the influence of moral philosophy on the ethical beliefs of auditors. The paper argues that an individual's moral philosophy is the key factor in how one views ethical issues and largely determines the ethical choices one makes. The paper also seeks to discover the influence of personal values on the reasoning processes associated with ethics and to explore whether the personal value preferences of auditors, as a manifestation of their moral philosophy, influence their ethical beliefs and (presumably) their subsequent actions.
Design/methodology/approach
The authors designed a survey instrument to assess the value preferences, moral philosophies, and reactions of practicing auditors to judgment dilemmas. They then employed structural equation modeling to examine the sensitivity of auditors to the competence and integrity of clients with the aim of gaining insight into the ethical beliefs of auditors in general.
Findings
These results show that value preferences alone fail as predictors of ethical beliefs. Instead, personal values have an indirect influence on ethical beliefs via moral philosophy. Moreover, auditors strongly motivated by values based on self‐enhancement were negatively associated with idealism in ethics and positively associated with relativism. Therefore, it can be concluded that idealist auditors were more likely to condemn the actions of clients that violated moral norms, while relativist auditors were more permissive.
Originality/value
The results identify the role of moral philosophy as a mediator for the personal values and ethical beliefs of auditors, shedding light on how personal values can influence ethical sensitivity.
Details
Keywords
The cardinal purpose of mathematical analysis is to establish the validity of the concepts, theorems and artifices which comprise the mathematical machine, and to prescribe the…
Abstract
The cardinal purpose of mathematical analysis is to establish the validity of the concepts, theorems and artifices which comprise the mathematical machine, and to prescribe the limitations and reservations to which the operations by this machine are subject.