Search results

This paper aims to inspect the effect of indirect elevated temperature on the mechanical performance of nano silica concrete (NSC). The effect on both compressive and bond strengths is studied. Pre- and post-exposure to elevated temperature ranges of 200 to 600°C is examined. A range covered by three percentages of 1.5, 3 and 4.5 per cent nano silica (NS) in concrete mixes is tested.

Pre-exposure mechanical tests (normal conditions – room temperature), using 3 per cent NS in the concrete mix, led to the highest increase in both compressive and bond strengths (43 per cent and 38.5 per cent, respectively), compared to the control mix without NS (based on 28-day results). It is worth noticing that adding NS to the concrete mixes does not have a significant effect on improving early-age strength. Besides, permeability tests are performed on NSC with different NS ratios. NS improved the concrete permeability for all tested percentages of NS. The maximum reduction is accompanied by the maximum percentage used (4.5 per cent NS in the NSC mix), reducing permeability to half the value of the concrete mix without NS. As for post-exposure to elevated-temperature mechanical tests, NSC with 1.5 per cent NS exhibited the lowest loss in strength owing to indirect heat exposure of 600°C; the residual compressive and bond strengths are 73 per cent and 35 per cent, respectively.

The dispersion technique of NS has a key role in NSC-distinguished mechanical performance with NSC having lower NS percentages. NS significantly improved bond strength. NS has a remarkable effect on elevated temperature endurance. The bond strength of NSC exposed to elevated temperatures suffered faster deterioration than compressive strength of the exposed NSC.

A special scale factor needs to be investigated for the NSC.

Although a lot of effort is placed in evaluating the benefits of using nano materials in structural concrete, this paper presents one of the first outcomes of the thermal effects on concrete mixes with NS as a partial cement replacement.

Nano-Clay (NC) is reported as a candidate partial replacement for cement, due to its abundance and relatively low cost - beside reported promotion of different concrete properties. On the other hand, Steel Fibres (SF) has proven to have a positive effect on post fire exposure residual strength of concrete. This paper aims to present the outcomes of a comprehensive research program assessing a hybrid mix between NC and SF in concrete mixtures (NCSF-CRETE).

Physical chemical and physical characterization of NC is performed using different tools as XRF spectrometer, and TEM micrograph. Fresh concrete properties of NSCF-CRETE as slump and air content are investigated. Enhancement in permeability using NSCF is verified by comparing its resistance to the penetration of chlorides resistance with regular concrete mix. Besides, the proposed NCSF-CRETE compressive strength is evaluated compared to mixes with NC and SF each used separately at different curing ages. Besides, NSCF and compared mixes are exposed to an indirect fire testing program – two hours exposure – for: 300, 450 and 600°C. Degradation in compressive strength was investigated after exposure to different temperatures and percentage of residual strength is reported.

Results indicated an improved performance of NCSF -CRETE of about 40% compared to regular concrete in compressive strength at normal conditions. This improvement extended to its behavior when subjected to indirect fire exposure NSCF also maintained 40% more strength than the residual in regular concrete mix – which suffered severe damage – after 2 h exposure to 600°C.

Using NCSF-Crete allows retrofitting the structure after exposure to such drastic conditions.

The research works concerned with heritage management, in general, are available domestically and globally, but they are not as abundant as required when it comes to the management of twentieth-century urban heritages, particularly the Somali region. Thus, this research is assumed as innovative and evocative of additional research initiatives in the management of twentieth-century urban heritages, and it can assure the development of sustainable heritage tourism in the research area.

The study employed a cross-sectional survey as the research design, and qualitative data of both primary and secondary types were collected for this research. Therefore, purposively selected knowledgeable individuals in heritages of the study area were involved in in-depth interviews and focus group discussions, and field surveys of twentieth-century built urban heritage sites were conducted in Jigjiga, Erer and Qebridahar cities. Generally, observation, face-to-face interview interviews and focused group discussions were used to collect primary data, and document analysis was also used to collect secondary data.

The findings of the study revealed that the Somali region is rich in twentieth-century urban built heritage. The imperial palace, administrative centers, mosques, shrines, churches, military camps, Italian-built architecture sites, patriot centers, statues of local heroes, older bus stations and city centers are among the twentieth-century built heritages in the region. However, most of these heritages were not recognized. Consequently; conservation, promotion and use of the twentieth-century urban heritages for sustainable development are given little attention despite that there are infrastructural facilities for tourists in the region and the proximity of the region to the heritage tourism corridors of Harar and Dire Dawa.

Awareness should be made to the concerned institutions and societies about socio-economic and cultural values of the twentieth-century urban built heritage.

The Federal Culture and Tourism Ministry and Culture and Tourism Bureau of the Somali region should cooperatively develop a short and long-term plan of action to manage the twentieth-century built urban heritage of the region and use them for sustainable development through the participation of the society.

The local institutions, communities and individuals should be aware of and involved in the conservation, promotion and use of the twentieth-century built urban heritages for sustainable social, cultural and economic development.

As far as the researchers' knowledge is concerned, there is no research of a similar type in which the setting and results are closer to this. Therefore, this research is original and is based on extensive primary data gathered from field surveys.

This paper presents the second part of the investigation on resistance to elevated temperatures of a proposed hybrid composite concrete (NCSF-Crete) mix. The composite including nano metakaolin (NC) and steel fibers (SF) in addition to regular concrete components has proven -in the first published part-earlier promoted fresh concrete behavior, and to have reduced loss in compressive strength after exposure to a wide range of elevated temperatures. This presented work evaluates another two critical mechanical characteristics for the proposed composite -namely- splitting and bond strengths.

A modified formula correlating splitting and compressive strength (28 days) based on experiments results for NCSF is proposed and compared to formulas derived for regular concrete in different design codes. Finally, both spitting and bond strengths are evaluated pre- and post-exposure to elevated temperatures reaching 600 °C for two hours.

The proposed NCSF-Crete shows remarkable fire endurance, especially in promoting bond strength as after 600 °C heat exposure tests, it maintained strength equivalent to 70% of a regular concrete control mix at room temperature. Improving residual splitting strength was very significant up to 450 °C exposure.

Obvious deterioration is monitored in splitting resistance for all concretes at 600 °C.

This proposed composite improved elevated heats resistance of the most significant concrete mechanical properties.

Using a more green and sustainable constituents in the composite.

The proposed composite gathers the merits of using NC and SF, each has been investigated separately as an addition to concrete mixes.

This paper aims to examine the effects of taqwa (God-consciousness) and syukr (gratitude to God) on emotional intelligence (EI) in a Muslim population in Malaysia.

Structural equation modelling tool AMOS was used to test the study’s hypotheses. In total, data were sourced from 302 Muslim employees working in Malaysia's public and private sectors.

Taqwa and syukr positively influence EI, and people with taqwa and syukr demonstrate greater levels of self-emotional appraisal compared with other emotional appraisals. This study also shows that people with taqwa and syukr give increased priority to understanding and distinguishing positive and negative emotions because of their understanding of Islamic teachings. They also exhibit concern with knowing their emotions well before advising or responding to the emotions of others. This may increase their sense of empathy, thereby improving their emotional competency and EI.

The findings indicate that taqwa and syukr predispose Muslims to EI. This study applied the Qur’anic model of self-development, which connects the origin of emotion with the soul, thereby further enriching the literature on the subject. It also highlights the importance of taqwa and syukr to Muslim employees for achieving EI that is useful in creating a harmonious atmosphere in the workplace and prosperous relationships in society.

Authenticity/ الصحة (as-sehah) serves as a criterion or predictor variable for the purpose of a comparative theological investigation of employment relations parameters in light of social teachings from Sunni Islam and Roman Catholicism. Authenticity finds initial, shared significance in both religious traditions because of its critically important role in judgments concerning the legitimacy of source documents. It also stands in both traditions as an inspirational goal for human life.

Particular issues of theological method for cross-cultural analysis are addressed by the use of insight-based critical realism as a transcultural foundation. Workplace parameters, the minimal enabling conditions for the possibility of authentic employment relations, are then identified and compared. The authors explore shared expectations for authenticity enabling conditions in terms of the direct and indirect employer: those national laws, systems and traditions that condition the functional range of authenticity that can be actualized within national or other work settings as experienced in the direct employment contract.

The study found remarkable consistency in the minimal conditions identified by Roman Catholic and Sunni Islam social teachings for the prospects of authenticity in employment relations. These conditions addressed seven parameters: work and the concept of labor; private property; the nature of the employment contract; unions and collective bargaining; the treatment of wages; the relationship between managerial prerogative and employee participation; and the crucial role of the state as indirect employer.

Specific minimal or threshold conditions of employment are described to ensure the prospect for authenticity in modern employment relations according to religious traditions. These include just cause employment conditions, unions and collective bargaining support, some form of management consultation/Shura, a living wage and a consultative exercise of managerial prerogative.

The study offers prescriptive and analytical aid to ensure assessment of circumstances fostering authenticity in employment relations.

The method and findings are a first effort to clarify thought and aid mutual understanding for inter-faith employment circumstances based on Roman Catholic and Sunni Islam social teachings through a transcultural foundation in cognitional operations. The criterion variable specification of authenticity conditions offers a fully developed basis to support further empirical research in management spirituality, corporate social responsibility and enterprise sustainability.

This study investigates the flow and heat transfer in a magnetohydrodynamic (MHD) ternary hybrid nanofluid (HNF), considering the effects of viscous dissipation and radiation.

The transport equations are transformed into nondimensional partial differential equations. The local nonsimilarity (LNS) technique is implemented to truncate nonsimilar dimensionless system. The LNS truncated equation can be treated as ordinary differential equations. The numerical results of the equation are accomplished through the implementation of the bvp4c solver, which leverages the fourth-order three-stage Lobatto IIIa formula as a finite difference scheme.

The findings of a comparative investigation carried out under diverse physical limitations demonstrate that ternary HNFs exhibit remarkably elevated thermal efficiency in contrast to conventional nanofluids.

The LNS approach (Mahesh et al., 2023; Khan et al., 20223; Farooq et al., 2023) that we have proposed is not currently being used to clarify the dynamical issue of HNF via porous media. The LNS method, in conjunction with the bvp4c up to its second truncation level, yields numerical solutions to nonlinear-coupled PDEs. Relevant results of the topic at hand, obtained by adjusting the appropriate parameters, are explained and shown visually via tables and diagrams.