Life Cycle Assessment for Fiber-Reinforced Polymer (FRP)nComposites Used in Concrete Beams: A State-of-the-Art Review

Fiber-reinforced polymer (FRP) composites have become popularly utilized in structural engineering applications. The common use of the FRP composites is related to their economic benefits that can be observed right away or in a long-time period. With increasing concern about global warming and the shortage of natural resources, it is essential to study the environmental implications of the use of FRP composites. Life cycle assessment (LCA) is one of the most common techniques that can be used to take the environmental impact of the FRP into consideration. This paper presents a literature review about the LCA of FRP composites in concrete beams. The LCA results reported in the literature confirmed the use of FRP composites for reinforcing the RC beams instead of conventional steel rebars or that the strengthening of RC beams instead of demolishing and reconstruction is a more environment-friendly approach

Optimum Dispersion Parameters of Carbon Nanotubes: Concrete Strength by Response Surface Methodologies

"This paper implements Response Surface Methodologies (RSM) techniques to illustrate the maximum carbon nanotubes (CNTs)-concrete mechanical properties responses to the length, weight fraction and treatment variables. Mixes with different CNTs’ content were prepared and tested for flexure, compression and tension. RSM analysis showed that the highest effect on the strengths was due to the CNTs’ content variable. The analysis showed that a weight fraction of 0.3 wt.% of non-treated CNTs is required to achieve the maximum flexural, compressive and tensile strengths in a batch as per the predicted model. RSM analysis also showed that maximum flexural strength will be obtained by using 0.2 wt. % non-treated long CNTs, 0.25 wt. % non-treated short CNTs and 0.03 wt. % treated long CNTs, respectively.

Carbon nanotube effect on the ductility, flexural strength, and permeability of concrete

Recently, remarkable types of carbon nanofilaments called carbon nanotubes (CNTs) have raised the interest of many concrete and cementitious composite researchers due to their significant mechanical, electrical, thermal, kinetic, and chemical properties. These nanofilaments are considered promising applicants to use in producing high-performance cement-based composite materials. In this research, the effect of CNT use on the flexural strength, strain capacity, permeability, and microstructure of concrete was investigated. Concrete batches of 0, 0.03, 0.08, 0.15, and 0.25 wt.% CNTs were prepared using a mixing method that consisted of a 30-minute solution sonication and a 60-minute batch mixing. On the 28th day, the mechanical properties were determined. The results indicated that concrete prepared using high CNT contents of 0.15 and 0.25 wt.% increased the flexural strength by more than 100% in comparison with 0% CNT concrete. Furthermore, the results showed that CNTs would increase the ductility of concrete beams by about 150%. The permeability test results showed the benefits of CNT inclusion in reducing the permeability of concrete. The permeability coefficient (kT) decreased by at least 45% when CNTs were added to concrete. A qualitative microstructural analysis illustrated the uniform dispersion of CNT filaments within the concrete hydration products in all batches.Scopu

Integrated TOPSIS-COV approach for selecting a sustainable PET waste management technology: A case study in Qatar

In 2018, the global annual consumption of Polyethylene terephthalate (PET) bottles was approximately 27.64 million tons, with one million bottles sold worldwide every minute. Unmanaged PET bottles in the environment lead to a series of negative effects on the health of humans and ecosystems. Therefore, the objective of this research was to evaluate the sustainability of eight different PET waste bottle treatment methods using a holistic multi-criteria decision-making approach that combined the technique for order of preference by similarity to ideal solution (TOPSIS) with analytic hierarchy (AHP; TOPSIS-AHP) and coefficient of variation (COV; TOPSIS-COV) approaches. To the best of our knowledge, TOPSIS-COV has not yet been used for waste management. The treatment methods were compared and analyzed against twelve different performance criteria representing three pillars of sustainability: environmental, economic, and social. Both approaches determined closed-loop recycling to be optimal for treating PET waste bottles. The weights of performance indicators obtained using the COV and AHP approaches were comparable, except for cost, photochemical oxidant potential, and human toxicity. The large dispersion in the values of the photochemical oxidant potential causes it to have a higher weight in the COV approach. For cost, the weight was higher using the AHP approach by approximately 12%, which reflects the preference of decision-makers to reduce costs of ventures. 2022 The Author(s)This work was supported by the Awards GSRA4-1-0524-17104 from Qatar National Research Fund (a member of the Qatar Foundation). The contents herein are solely the responsibility of the authors.Scopu

A New Formula for the BER of Binary Modulations with Dual-Branch Selection over Generalized-K Composite Fading Channels

Error performance is one of the main performance measures and derivation of its closed-form expression has proved to be quite involved for certain systems. In this letter, a unified closed-form expression, applicable to different binary modulation schemes, for the bit error rate of dual-branch selection diversity based systems undergoing independent but not necessarily identically distributed generalized-K fading is derived in terms of the extended generalized bivariate Meijer G-function.Comment: Diversity schemes, selection combining, dual-branch selection diversity, binary modulation schemes, generalized-K (GK) model, composite fading, bit error rate (BER), and Meijer G-function distributio

Survey and molecular detection of Melissococcus plutonius, the causative agent of European Foulbrood in honeybees in Saudi Arabia

AbstractA large-scale field survey was conducted to screen major Saudi Arabian beekeeping locations for infection by Melissococcus plutonius. M. plutonius is one of the major bacterial pathogens of honeybee broods and is the causative agent of European Foulbrood disease (EFB). Larvae from samples suspected of infection were collected from different apiaries and homogenized in phosphate buffered saline (PBS). Bacteria were isolated on MYPGP agar medium. Two bacterial isolates, ksuMP7 and ksuMP9 (16S rRNA GenBank accession numbers, KX417565 and KX417566, respectively), were subjected to molecular identification using M. plutonius -specific primers, a BLAST sequence analysis revealed that the two isolates were M. plutonius with more than 98% sequence identity. The molecular detection of M. plutonius from honeybee is the first recorded incidence of this pathogen in Saudi Arabia. This study emphasizes the need for official authorities to take immediate steps toward treating and limiting the spread of this disease throughout the country

Short-, Medium-, and Long-Term Prediction of Carbon Dioxide Emissions using Wavelet-Enhanced Extreme Learning Machine

Carbon dioxide (CO2) is the main greenhouse gas responsible for global warming. Early prediction of CO2 is critical for developing strategies to mitigate the effects of climate change. A sophisticated version of the extreme learning machine (ELM), the wavelet enhanced extreme learning machine (W-EELM), is used to predict CO2 on different time scales (weekly, monthly, and yearly). Data were collected from the Mauna Loa Observatory station in Hawaii, which is ideal for global air sampling. Instead of the traditional method (singular value decomposition), a complete orthogonal decomposition (COD) was used to accurately calculate the weights of the ELM output layers. Another contribution of this study is the removal of noise from the input signal using the wavelet transform technique. The results of the W-EELM model are compared with the results of the classical ELM. Various statistical metrics are used to evaluate the models, and the comparative figures confirm the superiority of the applied models over the ELM model. The proposed W-EELM model proves to be a robust and applicable computer-based technology for modeling CO2concentrations, which contributes to the fundamental knowledge of the environmental engineering perspective. Doi: 10.28991/CEJ-2023-09-04-04 Full Text: PD

Towards a cyber resilience quantification framework (CRQF) for IT infrastructure

Cyber resilience quantification is the process of evaluating and measuring an organisation’s ability to withstand, adapt to, and recover from cyber-attacks. It involves estimating IT systems, networks, and response strategies to ensure robust defence and effective recovery mechanisms in the event of a cyber-attack. Quantifying cyber resilience can be difficult due to the constantly changing components of IT infrastructure. Traditional methods like vulnerability assessments and penetration testing may not be effective. Measuring cyber resilience is essential to evaluate and strengthen an organisation’s preparedness against evolving cyber-attacks. It helps identify weaknesses, allocate resources, and ensure the uninterrupted operation of critical systems and information. There are various methods for measuring cyber resilience, such as evaluating, teaming and testing, and creating simulated models. This article proposes a cyber resilience quantification framework for IT infrastructure that utilises a simulation approach. This approach enables organisations to simulate different attack scenarios, identify vulnerabilities, and improve their cyber resilience. The comparative analysis of cyber resilience factors highlights pre-configuration’s robust planning and adaptation (61.44%), buffering supported’s initial readiness (44.53%), and network topologies’ robust planning but weak recovery and adaptation (60.04% to 77.86%), underscoring the need for comprehensive enhancements across all phases. The utilisation of the proposed factors is crucial in conducting a comprehensive evaluation of IT infrastructure in the event of a cyber-attack

Medication Sector in Qatar: Hand in Hand Facing the Blockade

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