Machine Learning-Based Prediction of Compressive Performance in Circular Concrete Columns Confined with FRP

This article presents a comprehensive investigation, focusing on the prediction and formulation of the design equation of compressive strength of circular concrete columns confined with Fiber Reinforced Polymer (FRP) using advanced machine learning models. Through an extensive analysis of 170 experimental data specimens, the study examines the effects of six key parameters, including concrete cylinder diameter, concrete cylinder-FRP thickness, compressive strength of concrete without FRP, initial compressive strain of concrete without FRP, elastic modulus and tensile strength of FRP, on the compressive strength of the circular concrete columns confined with FRP. The predictive model and design equation of compressive strength is developed using a machine learning technique, specifically the artificial neural networks (ANN) model. The results demonstrates strong correlations between the compressive strength of the circular concrete columns confined with FRP and certain factors, such as the compressive strength of the concrete and compressive strain of the concrete column without FRP, elastic modulus of FRP, and tensile strength of FRP. The ANN model specifically developed using Neural Designer, exhibits superior predictive accuracy compared to other constitutive models, showcasing its potential for practical implementation. The study's findings contribute valuable insights into accurately predicting the compressive performance of circular concrete columns confined with FRP, which can aid in optimizing and designing civil engineering structures for enhanced performance and efficiency

Potential of natural fibres and their composites for South Asian countries: Moving towards sustainability

Increased environmental concerns and depletion of petroleum-based resources arising from the use of non-renewable resources have increased the demand of natural fibre reinforced composites (NFRCs). Composite materials reinforced with glass and carbon fibres have limited end-of-life (EoL) options, which is a major concern. To minimise this situation, lignocellulose plant fibres have been studied extensively in recent years, due to the increasing demand for sustainable lightweight and environmentally friendly materials. Natural plant fibres are considered as a viable substitute to E-glass fibres owing to their many attractive benefits, such as biodegradable, recyclability, high specific strength and stiffness suitable as reinforcements for many semi-structural and structural composite applications. This new class of lightweight sustainable composites can offer environmental, social and economic benefits as substitute materials for various applications. Through an up-to-date review, this work presents an overview of natural plant fibres as reinforcements of composites for various applications, especially in the context of the South Asian countries.Final Published versio

On Load balancing in distributed systems with large time delays: Theory and experiment

In a distributed computing environment with a high communication cost, limiting the number of balancing instants results in a better performance than the case where load balancing is executed continuously. Therefore, finding the optimal number of balancing instants and optimizing the performance over the interbalancing time and over the load-balancing gain becomes an important problem. In this paper we discuss the performance of a previously reported, control-theoretic motivated single load-balancing strategy on a distributed physical system and the performance is compared to our simulation predictions. Based on the concept of regeneration, we also present a mathematical model for the distributed system with two nodes where a one-shot balancing is done. We obtain a system of four difference-differential equations characterizing the mean of the overall completion time. and compare its predictive capabilities via simulation to the physical system

Abrasive water jet drilling of advanced sustainable bio-fibre-reinforced polymer/hybrid composites : a comprehensive analysis of machining-induced damage responses

This paper aims at investigating the effects of variable traverse speeds on machining-induced damage of fibre-reinforced composites, using the abrasive water jet (AWJ) drilling. Three different types of epoxy-based composites laminates fabricated by vacuum bagging technique containing unidirectional (UD) flax, hybrid carbon-flax and carbon fibre-reinforced composite were used. The drilling parameters used were traverse speeds of 20, 40, 60 and 80 mm/min, constant water jet pressure of 300 MPa and a hole diameter of 10 mm. The results obtained depict that the traverse speed had a significant effect with respect to both surface roughness and delamination drilling-induced damage responses. Evidently, an increase in water jet traverse speed caused an increase in both damage responses of the three samples. Significantly, the CFRP composite sample recorded the lowest surface roughness damage response, followed by C-FFRP, while FFRP exhibited the highest. However, samples of FFRP and hybrid C-FFRP recorded lowest and highest delamination damage responses, respectively. The discrepancy in both damage responses, as further validated with micrographs of colour video microscopy (CVM), scanning electron microscopy (SEM) and X-ray micro-computed tomography (X-ray μCT), is attributed to the different mechanical properties of the reinforced fibres, fibre orientation/ply stacking and hybridisation of the samples.Peer reviewe

Characterization of Nano-Mechanical, Surface and Thermal Properties of Hemp Fiber-Reinforced Polycaprolactone (HF/PCL) Biocomposites

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).The quest for sustainable, low-cost and environmental friendly engineering materials has increased the application of natural fiber-reinforced polymer (FRP) composite. This paper experimentally investigates the effects of variable mean hemp fiber (HF) aspect ratios (ARs) of 00 (neat), aspect ratios AR_19, AR_26, AR_30 and AR_38 on nano-mechanical (hardness, modulus, elasticity and plasticity), surface and thermal properties of hemp fiber/polycaprolactone (HF/PCL) biocomposites. These biocomposites were characterized by nanoindentation, contact angle, surface energy, thermogravimetric analysis (TGA), thermal conductivity and differential scanning calorimetry (DSC) techniques. After nanoindentation and thermal conductivity tests, the results obtained evidently show that the HF/PCL sample with aspect ratio (AR_26) recorded optimal values. These values include maximum hardness of approximately 0.107 GPa, elastic modulus of 1.094 GPa, and plastic and elastic works of 1.580 and 1.210 nJ, respectively as well as maximum thermal conductivity of 0.2957 W/m.K, when compared with other samples. Similarly, the optimal sample exhibits highest main degradable temperature and degree of crystallinity of 432 ℃ and 60.6%, respectively. Further results obtained for the total surface energies and contact angles of these samples with glycerol and distilled water are significant for their materials selection, design, manufacturing and various applications.Peer reviewedFinal Published versio

The post-impact response of flax/UP composite laminates under low velocity impact loading

Flax fiber reinforced unsaturated polyester (UP) composite laminates were fabricated by vacuum bagging process and their impact and post-impact responses was investigated through experimental testing and finite element simulations. Samples of 60 mm x 60 mm x 6.2 mm were cut from the composite laminates and were subjected to a low-velocity impact loading to near perforation using hemispherical steel impactor at three different energy levels, 25, 27 and 29 Joules, respectively. Post impact with incident energy of 25 Joules was employed to occure full penetration. The impacted composite plates were modelled with various lay-ups using finite element software LS-DYNA (LS-DYNA User’s Manual 1997) to provide a validated FE model for the future investigations in the field. The effects of impact and post impact on the failure mechanisms were evaluated using scanning electron microphotography (SEM). Parameters measured were load bearing capability, energy absorption and damage modes. The results show a significant reduction in impact strength after post impact events at all energy levels

The Impact of Leprosy on Marital Relationships and Sexual Health among Married Women in Eastern Nepal

Background. Leprosy is one of the most stigmatized diseases known today. The stigma surrounding leprosy can be a major burden and affects many dimensions of a person’s life, including intimate relationships. We aimed to investigate the experiences of women affected by leprosy regarding marital life and sexuality, comparing these to the experiences of women with other physical disabilities and to those of able-bodied women in South-East Nepal. Methods. This study used a qualitative approach and a cross-sectional, nonrandom survey design. Thirty women underwent in-depth interviews about their marital and sexual relationship by means of a semi-structured interview guide. These thirty women included ten women affected by leprosy, ten women with other physical disabilities, and ten able-bodied women living in South-East Nepal. Results. We found that many women faced violence and abuse in their marriages. However, women affected by leprosy appeared to face more problems with regard to their marital and sexual relationships than women with physical disabilities and able-bodied women. Some of these related to the fear of leprosy. Conclusions. Further research is recommended to investigate the extent of this problem and ways to ameliorate the situation of the affected women. Education and counselling at diagnosis may help prevent many of the problems reported

Urban energy consumption and CO2 emissions in Beijing: current and future

This paper calculates the energy consumption and CO2 emissions of Beijing over 2005–2011 in light of the Beijing’s energy balance table and the carbon emission coefficients of IPCC. Furthermore, based on a series of energy conservation planning program issued in Beijing, the Long-range Energy Alternatives Planning System (LEAP)-BJ model is developed to study the energy consumption and CO2 emissions of Beijing’s six end-use sectors and the energy conversion sector over 2012–2030 under the BAU scenario and POL scenario. Some results are found in this research: (1) During 2005–2011, the energy consumption kept increasing, while the total CO2 emissions fluctuated obviously in 2008 and 2011. The energy structure and the industrial structure have been optimized to a certain extent. (2) If the policies are completely implemented, the POL scenario is projected to save 21.36 and 35.37 % of the total energy consumption and CO2 emissions than the BAU scenario during 2012 and 2030. (3) The POL scenario presents a more optimized energy structure compared with the BAU scenario, with the decrease of coal consumption and the increase of natural gas consumption. (4) The commerce and service sector and the energy conversion sector will become the largest contributor to energy consumption and CO2 emissions, respectively. The transport sector and the industrial sector are the two most potential sectors in energy savings and carbon reduction. In terms of subscenarios, the energy conservation in transport (TEC) is the most effective one. (5) The macroparameters, such as the GDP growth rate and the industrial structure, have great influence on the urban energy consumption and carbon emissions

Chapter 12 - Human settlements, infrastructure and spatial planning

Urbanization is a process that involves simultaneous transitions and transformations across multiple dimensions, including demographic, economic, and physical changes in the landscape. Each of these dimensions presents different indicators and definitions of urbanization. The chapter begins with a brief discussion of the multiple dimensions and definitions of urbanization, including implications for GHG emissions accounting, and then continues with an assessment of historical, current, and future trends across different dimensions of urbanization in the context of GHG emissions (12.2). It then discusses GHG accounting approaches and challenges specific to urban areas and human settlements. In Section 12.3, the chapter assesses the drivers of urban GHG emissions in a systemic fashion, and examines the impacts of drivers on individuals sectors as well as the interaction and interdependence of drivers. In this section, the relative magnitude of each driver's impact on urban GHG emissions is discussed both qualitatively and quantitatively, and provides the context for a more detailed assessment of how urban form and infrastructure affect urban GHG emissions (12.4). Here, the section discusses the individual urban form drivers such as density, connectivity, and land use mix, as well as their interactions with each other. Section 12.4 also examines the links between infrastructure and urban form, as well as their combined and interacting effects on GHG emissions. Section 12.5 identifies spatial planning strategies and policy instruments that can affect multiple drivers, and Section 12.6 examines the institutional, governance, and financial requirements to implement such policies. Of particular importance with regard to mitigation potential at the urban or local scale is a discussion of the geographic and administrative scales for which policies are implemented, overlapping, and / or in conflict. The chapter then identifies the scale and range of mitigation actions currently planned and / or implemented by local governments, and assesses the evidence of successful implementation of the plans, as well as barriers to further implementation (12.7). Next, the chapter discusses major co-benefits and adverse side-effects of mitigation at the local scale, including opportunities for sustainable development (12.8). The chapter concludes with a discussion of the major gaps in knowledge with respect to mitigation of climate change in urban areas (12.9)