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Article
Publication date: 25 August 2021

Asif Ur Rehman and Vincenzo M. Sglavo

Recent advances in 3D printing construction elements have focused on ordinary Portland cement (OPC) concrete using polymeric binders; herein, this study aims to produce…

Abstract

Purpose

Recent advances in 3D printing construction elements have focused on ordinary Portland cement (OPC) concrete using polymeric binders; herein, this study aims to produce the same using pure water.

Design/methodology/approach

A binder jet printer prototype was used to fabricate specimens that are used to assess geometric and mechanical properties. Two distinct water-based binder formulations, compatible with OPC chemistry and piezoelectric jetting device, were used: pure water and water-polyvinyl alcohol (98:2 w/w) solution.

Findings

This study examines the effect of binder flow rate on dimensional accuracy. Furthermore, the changes in the mechanical properties over time with hydration have been investigated.

Practical implications

Results indicate that the increase in mechanical strength of Portland cement concrete with pure water was consistent; however, it was delayed by the water: PVA (98:2 w/w) solution. Post-curing by water vapor hardened the structure with the removal of layering native to 3DP and decreased infilling porosity by diffusion mechanism.

Originality/value

This paper has used pure water jetting for BJT of Portland cement-containing bodies.

Details

Rapid Prototyping Journal, vol. 28 no. 2
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 23 September 2020

Asif Ur Rehman and Vincenzo M. Sglavo

Three-dimensional (3D) printing technology allows geometric complexity and customization with a significant reduction in the structural environmental impact. Nevertheless…

Abstract

Purpose

Three-dimensional (3D) printing technology allows geometric complexity and customization with a significant reduction in the structural environmental impact. Nevertheless, it poses a serious threat to the environment when organic binders are used. Binder jet printing of alkali-activated geopolymer precursor can represent a successful and environmental-friendly alternative.

Design/methodology/approach

The present work reports about the successful 3D printing of metakaolin-based alkali-activated concrete, with dimensional integrity and valuable mechanical behavior.

Findings

The geometric behavior was studied as a function of alkali activator flow rate, and the minimum geometric deviation with complete saturation was recorded at 103 mg/s. The printed specimen is characterized by a modulus of rupture as high as 4.4 MPa at 135 mg/s.

Practical implications

The 3D printed geopolymer-based concrete can be potentially used in a wide range of structural applications from construction to thermal insulation elements.

Originality/value

The analysis of the 3D geopolymer-based concrete printing system and material conducted in this paper is original.

Details

Rapid Prototyping Journal, vol. 26 no. 10
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 19 May 2022

Abid Ullah, Asif Ur Rehman, Metin Uymaz Salamci, Fatih Pıtır and Tingting Liu

This paper aims to reduce part defects and improve ceramic additive manufacturing (AM). Selective laser melting (SLM) experiments were carried out to explore the effect of…

Abstract

Purpose

This paper aims to reduce part defects and improve ceramic additive manufacturing (AM). Selective laser melting (SLM) experiments were carried out to explore the effect of laser power and scanning speed on the microstructure, melting behaviour and surface roughness of cuprous oxide (Cu2O) ceramic.

Design/methodology/approach

The experiments were designed based on varying laser power and scanning speed. The laser power was changed between 50 W and 140 W, and the scanning speed was changed between 170 mm/s and 210 mm/s. Other parameters, such as scanning strategy, layer thickness and hatch spacing, remain constant.

Findings

Laser power and scan speed are the two important laser parameters of great significance in the SLM technique that directly affect the molten state of ceramic powders. The findings reveal that Cu2O part defects are widely controlled by gradually increasing the laser power to 110 W and reducing the scanning speed to 170 mm/s. Furthermore, excessive laser power (>120 W) caused surface roughness, cavities and porous microstructure due to the extremely high energy input of the laser beam.

Originality/value

The SLM technique was used to produce Cu2O ceramic specimens. SLM of oxide ceramic became feasible using a slurry-based approach. The causes of several part defects such as spattering effect, crack initiation and propagation, the formation of porous microstructure, surface roughness and asymmetrical grain growth during the SLM of cuprous oxide (Cu2O) are thoroughly investigated.

Details

Rapid Prototyping Journal, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1355-2546

Keywords

Article
Publication date: 12 November 2020

Abid Ullah, HengAn Wu, Asif Ur Rehman, YinBo Zhu, Tingting Liu and Kai Zhang

The purpose of this paper is to eliminate Part defects and enrich additive manufacturing of ceramics. Laser powder bed fusion (L-PBF) experiments were carried to…

Abstract

Purpose

The purpose of this paper is to eliminate Part defects and enrich additive manufacturing of ceramics. Laser powder bed fusion (L-PBF) experiments were carried to investigate the effects of laser parameters and selective oxidation of Titanium (mixed with TiO2) on the microstructure, surface quality and melting state of Titania. The causes of several L-PBF parts defects were thoroughly analyzed.

Design/methodology/approach

Laser power and scanning speed were varied within a specific range (50–125 W and 170–200 mm/s, respectively). Furthermore, varying loads of Ti (1%, 3%, 5% and 15%) were mixed with TiO2, which was selectively oxidized with laser beam in the presence of oxygen environment.

Findings

Part defects such as cracks, pores and uneven grains growth were widely reduced in TiO2 L-PBF specimens. Increasing the laser power and decreasing the scanning speed shown significant improvements in the surface morphology of TiO2 ceramics. The amount of Ti material was fully melted and simultaneously changed into TiO2 by the application of the laser beam. The selective oxidation of Ti material also improved the melting condition, microstructure and surface quality of the specimens.

Originality/value

TiO2 ceramic specimens were produced through L-PBF process. Increasing the laser power and decreasing the scanning speed is an effective way to sufficiently melt the powders and reduce parts defects. Selective oxidation of Ti by a high power laser beam approach was used to improve the manufacturability of TiO2 specimens.

Article
Publication date: 11 August 2020

Faheem Ur Rehman, Yibing Ding, Abul Ala Noman and Muhammad Asif Khan

Over the past two decades, China’s outward foreign direct investment (OFDI) has risen remarkably. Whether such an increase affects the Chinese export diversification (ED…

Abstract

Purpose

Over the past two decades, China’s outward foreign direct investment (OFDI) has risen remarkably. Whether such an increase affects the Chinese export diversification (ED) is a significant issue that has surprisingly remained unaddressed. This study aims to explain this issue that how OFDI plays a vital role in symmetric and asymmetric effects on its ED.

Design/methodology/approach

The authors introduce a robust nonlinear autoregressive distributed lag (NARDL) model. Ironically, the purpose of this study is to analyze the symmetric and asymmetric effect of OFDI on ED.

Findings

The authors propose that growing OFDI would be more advantageous to China, rather than the policies of contraction. Therefore, the study provides valuable policy insights to consider the long-run asymmetric momentum given to ED by China’s OFDI.

Originality/value

The results of this study may seem to be an important newsletter for further policy discussion on how China can catch up on the benefits of ED through OFDI.

Details

Journal of Chinese Economic and Foreign Trade Studies, vol. 13 no. 2
Type: Research Article
ISSN: 1754-4408

Keywords

Article
Publication date: 12 January 2021

Faheem Ur Rehman and Abul Ala Noman

China's outward foreign direct investment (OFDI) has risen remarkably over the past two decades. Does such increase affect the sophistication of Chinese exports, is a…

Abstract

Purpose

China's outward foreign direct investment (OFDI) has risen remarkably over the past two decades. Does such increase affect the sophistication of Chinese exports, is a significant issue that has surprisingly remained unaddressed? The purpose of this study is to investigate the impact of Chinese OFDI on bilateral export sophistication of China and its OFDI receiving partner countries during 2003–2017 by applying Poisson pseudo-maximum likelihood approach based on gravity model.

Design/methodology/approach

The analysis has been performed for total sample, region-wise grouped sample (Europe and Central Asia, Middle East and North Africa, Latin America and Caribbean, East Asia and Pacific, South Asia, North America and sub-Saharan Africa) and income-wise grouped sample (high income, upper middle income, lower middle income and lower income group sample).

Findings

The results confirmed the significant and positive effect of Chinese OFDI on bilateral export sophistication in total sample, regions-wise and income groups sample.

Originality/value

The study provides a helpful suggestion regarding policy towards achieving more sophistication in export and thus to achieve comparative advantage in trade.

Details

China Finance Review International, vol. 12 no. 1
Type: Research Article
ISSN: 2044-1398

Keywords

Article
Publication date: 11 November 2020

Faheem Ur Rehman and Abul Ala Noman

Infrastructure deficiency in Southeast Asian countries is ever growing and touched to a level where it harms the local economy as well as the international sector of the…

Abstract

Purpose

Infrastructure deficiency in Southeast Asian countries is ever growing and touched to a level where it harms the local economy as well as the international sector of the country. The gap between demand and supply for infrastructure is constantly on the upswing. The purpose of this study to investigate the effect of infrastructure on exports and foreign direct investment (FDI) inflow in selected Southeast Asian economies.

Design/methodology/approach

This study employs the pooled mean group (PMG) technique to velaborate that how the infrastructure affects export and FDI in the short run and long run during 1990–2018. For cointegration, Pedroni and Kao tests are used. Dynamic ordinary least square (DOLS) and the fully modified least squares (FMOLSs) estimators are employed for robustness check.

Findings

The findings support that aggregate and sub-indices of infrastructure significantly promote the export and FDI inflow in the long run. Also infrastructure, export and FDI inflow are cointegrated in the long run. FMOLS and DOLS found the most robust results.

Originality/value

Infrastructure development in determining trade and FDI has established a significant deal of attention in the modern era where a plethora of research studies encourage the opinion that better infrastructure attracts FDI and enhances export. However, this study uses a global infrastructure index, which comprises the sub-indices like transport, telecommunication, energy and financial sector, which gives us a clear picture regarding how Southeast Asia can catch up FDI and export benefits through infrastructure.

Details

Journal of Economic Studies, vol. 48 no. 7
Type: Research Article
ISSN: 0144-3585

Keywords

Article
Publication date: 30 August 2022

Faheem Ur Rehman, Md. Monirul Islam and Kazi Sohag

China's Belt and Road Initiative (BRI) is the most ambitious investment strategy for infrastructural development belonging to the significant potential for stimulating…

Abstract

Purpose

China's Belt and Road Initiative (BRI) is the most ambitious investment strategy for infrastructural development belonging to the significant potential for stimulating regional economic growth in Asia, Europe and Africa. This study aims to investigate the impact of infrastructure on spurring inward foreign direct investment (FDI) within the purview of human capital, GDP per capita, foreign aid, trade, domestic investment, population and institutional quality in BRI countries.

Design/methodology/approach

In doing so, the authors analyze panel data from 2000 to 2019 within the framework of the system generalized method of movement (GMM) approach for 66 BRI countries from Europe, Asia, Africa and the Middle East.

Findings

The investigated results demonstrate that aggregate and disaggregate infrastructure indices, e.g. transport, telecommunications, financial and energy infrastructures, are the driving forces in attracting foreign direct investment (FDI) in the BRI countries. In addition, control variables (i.e. institutional quality, human capital, trade, domestic investment, foreign aid and GDP per capita) play an essential role in spurring FDI inflows.

Originality/value

The authors’ study uniquely investigates both the pre- (2000–2012) and post- (2013–2019) BRI scenarios using the aggregate and disaggregate infrastructural components from the perspectives of full and clustered sample regions, such as Asia, Europe, Africa and the Middle East. The study provides several policy implications.

Details

International Journal of Emerging Markets, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1746-8809

Keywords

Book part
Publication date: 3 September 2021

Najma Sadiq

The restrictive measures related to the COVID-19 pandemic put a halt to everything across the world. The global crisis hit every sphere of life. The mobility restrictive…

Abstract

The restrictive measures related to the COVID-19 pandemic put a halt to everything across the world. The global crisis hit every sphere of life. The mobility restrictive nature of the pandemic was a major blow to the travel, tourism and hospitality industry. For a country like Pakistan, with an unstable economy and struggling tourism, the pandemic served as ground zero. This chapter critically examines tourism dimensions in Pakistan and how it sustained the impact of various crises. It pays attention to the concepts of vulnerability, social and community resilience, and adaptive capacity to provide a theoretical understanding of the revival of tourism in Pakistan. It also considers the impact of COVID-led measures on the tourism industry and corresponding initiatives of the government. The chapter concludes by arguing that Pakistan should carefully monitor and assess the current debates on tourism policies and practices. The chapter suggests that the national tourism strategy should incorporate a mechanism that can address tourism in crises in addition to addressing the environmental, socio-cultural and economic impact of tourism.

Open Access
Article
Publication date: 27 April 2022

Fahmida Akhter, Mohammad Rokibul Hossain, Hamzah Elrehail, Shafique Ur Rehman and Bashar Almansour

The study seeks to evaluate the extent and quality of environmental reporting following a longitudinal analysis and covering a wide spectrum of industries in a single…

Abstract

Purpose

The study seeks to evaluate the extent and quality of environmental reporting following a longitudinal analysis and covering a wide spectrum of industries in a single frame. The study also attempts to identify the set of most favored environmental reporting items by firms and items which are least disclosed. Furthermore, the study attempts to test whether certain corporate attributes such as firm size, age of the firm, leverage ratio, profitability, presence of independent directors in the board and gender diversity have any influencing power over environmental disclosure practices. The whole study has been carried out from legitimacy theory setting.

Design/methodology/approach

The study follows longitudinal analysis to identify the extent and quality of environmental disclosures. A self-constructed checklist of 12 environmental reporting items has been developed analyzing the annual report and content analysis method is followed to measure the extent and quality of environmental disclosures and identify environmental reporting items which are mostly disclosed and which are least disclosed. The study further uses panel data regression analysis to investigate whether certain corporate attributes have any impact on environmental disclosures using multiple linear regression. Total of 345 annual reports of listed financial and nonfinancial institutions have been observed in this study ranging from 2015 to 2019.

Findings

The key finding suggests that strict enforcement of Green Banking Rules 2011 fosters country’s commercial banks to invest more to protect the environment and commercial banks encourage nonfinancial institutions for environmental performance and related disclosures through finance. Therefore, almost 50% of sample firms disclose their environmental performance through reporting in either narrative, quantitative or monetary format which was only 2.23% in the last decade. Findings also reveal that tree plantation is the most reported environment disclosure followed by investment in renewable energy and green infrastructural projects and the least reported items are fund allocation for climatic changes and carbon management policy. Further analysis shows that firm size and leverage ratio both have positive impact on environmental reporting.

Research limitations/implications

An in-depth analysis may be conducted to identify why certain environmental items are least disclosed such as fund allotment for climatic changes, carbon management policy, etc. and how corporations may earn social appreciation and motivation by investing in those least preferred items in legitimacy theory setting. Future research may also take into consideration other corporate attributes which are not considered in the study.

Originality/value

The study conducted an in-depth analysis to understand the most favored form of environmental disclosures (narrative/quantitative/monetary) and their extent after incorporation of regulatory guidelines, which is the first of its kind in the research of environmental disclosures. The study indeed contributes to the documentation of environmental reporting in the context of a developing country where there is a lack of longitudinal analysis from the lens of legitimacy theory. Moreover, a wide spectrum of industries has been taken into consideration which facilitates the generalized findings on the environmental disclosure practices of corporations in Bangladesh.

研究目的

本研究擬評估公司報告環境方面的程度和質量, 以及對就環境報告披露而言、最受青睞和最不受歡迎的項目加以處理。研究亦擬測試企業屬性對實踐環境信息披露的影響。

研究方法

研究使用內容分析法、去測量環境信息披露的程度和質量。研究使用多元回歸分析、去探討企業屬性對環境信息披露的影響。研究涵蓋孟加拉國上市公司共345個年度報告, 涵蓋的年期為2015年至 2019年。

研究結果

研究結果似乎顯示綠色金融規則 - 2011 、成功鼓勵機構為保護環境而投放更多資源; 機構最樂於匯報的項目為植樹, 而披露最少的則為氣候變化和碳管理政策。進一步的研究分析顯示, 公司的規模和杠杆比率均會對環境匯報帶來正面的影響。

研究的原創性/新穎性

本研究豐富了關於發展中國家環境匯報的官方文件記錄, 而在這類國家, 透過合法化理論而進行的縱貫性分析研究頗為缺乏。本研究以深度分析法、去瞭解環境信息披露方面最受青睞的信息披露方式 (故事形式的敘述/定量形式/金融形式), 也去瞭解納入強制的規管指引後環境信息披露的程度; 就此而言, 本研究為這類環境信息披露研究的首個研究。

Details

European Journal of Management and Business Economics, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 2444-8451

Keywords

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