EFFECT OF WASTE POLYETHYLENE TEREPHTHALATE BOTTLE FIBERS ON THE MECHANICAL PROPERTIES OF RECYCLED CONCRETE

The use of beverage containers, most of which are made of polyethylene terephthalate bottles, results in several problems with regard to sustainability. The purpose of this study was to evaluate and contrast the impact on the mechanical characteristics of concrete caused by the incorporation of polyethylene terephthalate bottle fibres in varying amounts. These fibres were generated by cutting bottles into precise dimensions (width of 5 mm and length of 25 mm), and they were used in various concentrations such as 0,25 %; 0,5 % and 1,0 % by volume of concrete with different amounts of recycled aggregate. To verify the reliability of the outcomes of the experiment, a statistical analysis was performed. According to the results, the concrete that contained 0 % recycled coarse aggregate and varying amounts of plastic fibres had a greater degree of workability compared with concrete that had either 50 % or 100 % recycled coarse aggregate. The comprehensive test findings demonstrated that the addition of polyethylene terephthalate fibres decreased compressive and split tensile strength. The study concluded that certain parameters, such as plastic fibres, curing days, and recycled aggregate, interacted together in a synergistic manner to impact the compressive and splitting tensile strengths of the concrete, with proposed equations for their prediction

EFFECT OF WASTE POLYETHYLENE TEREPHTHALATE BOTTLE FIBERS ON THE MECHANICAL PROPERTIES OF RECYCLED CONCRETE

The use of beverage containers, most of which are made of polyethylene terephthalate bottles, results in several problems with regard to sustainability. The purpose of this study was to evaluate and contrast the impact on the mechanical characteristics of concrete caused by the incorporation of polyethylene terephthalate bottle fibres in varying amounts. These fibres were generated by cutting bottles into precise dimensions (width of 5 mm and length of 25 mm), and they were used in various concentrations such as 0,25 %; 0,5 % and 1,0 % by volume of concrete with different amounts of recycled aggregate. To verify the reliability of the outcomes of the experiment, a statistical analysis was performed. According to the results, the concrete that contained 0 % recycled coarse aggregate and varying amounts of plastic fibres had a greater degree of workability compared with concrete that had either 50 % or 100 % recycled coarse aggregate. The comprehensive test findings demonstrated that the addition of polyethylene terephthalate fibres decreased compressive and split tensile strength. The study concluded that certain parameters, such as plastic fibres, curing days, and recycled aggregate, interacted together in a synergistic manner to impact the compressive and splitting tensile strengths of the concrete, with proposed equations for their prediction

28.2%-efficient, outdoor-stable perovskite/silicon tandem solar cell

Stacking perovskite solar cells onto crystalline silicon bottom cells in a monolithic tandem configuration enables power-conversion efficiencies (PCEs) well above those of their single-junction counterparts. However, state-of-the-art wide-band-gap perovskite films suffer from phase stability issues. Here, we show how carbazole as an additive to the perovskite precursor solution can not only reduce nonradiative recombination losses but, perhaps more importantly, also can suppress phase segregation under exposure to moisture and light illumination. This enables a stabilized PCE of 28.6% (independently certified at 28.2%) for a monolithic perovskite/silicon tandem solar cell over ∼1 cm2 and 27.1% over 3.8 cm2, built from a textured silicon heterojunction solar cell. The modified tandem devices retain ∼93% of their performance over 43 days in a hot and humid outdoor environment of almost 100% relative humidity over 250 h under continuous 1-sun illumination and about 87% during a 85/85 damp-heat test for 500 h, demonstrating the improved phase stability

The Art of Manipulating Masses and Failure of Leadership in Orwells Animal Farm and Pakistani Politics: A Comparative Study

Purpose: The purpose of this research study is to comparatively study George Orwell’s Animal Farm (1945) and Pakistani political scenario. The study attempts to find similarities between the two from various aspects such as economy, freedom of speech, leadership, etc., and their effect on the masses. Design/Methodology/Approach: The study is mainly qualitative as the evidence is gathered from the novella Animal Farm and the public speeches, interviews, and from the social media handles of leading politicians. Critical Discourse Model (CDA), developed by Van Dijk (2001), is employed for the analysis and discussion. The selected texts were then contextualized for comparative analysis.  Findings: The textual evidence collected from the novella Animal Farm and the speeches, interviews, and social media posts from the political leaders reveal that there are certain common elements in both parties. The common elements include censorship on freedom of expression, lack of deliverance on the part of leadership, worsening economy, etc. Implications/Originality/Value: This research study is significant in the sense it is applicable on various levels such as leadership and its role in shaping the fate of society, the importance of freedom of speech as it paves the way for discussion for a better future of a nation. It also discusses the reason for the failure of economy. Furthermore, it is applicable to prevail justice and equality in society in all forms. This study aimed at discussing the common elements between Animal Farm and Pakistani politics. This is, to the best of my knowledge, perhaps, the first attempt in this regard. It is beneficial for readers in the sense that it provides them to relate the fictional world of Animal Farm to the real happenings in society and its impact on members of the society. Furthermore, it is suggestive in the sense that it provides a solution/alternative for the politicians and stakeholders of the state

n‑MoS₂/p-Si Solar Cells with Al₂O₃ Passivation for Enhanced Photogeneration

Molybdenum disulfide (MoS₂) has recently emerged as a promising candidate for fabricating ultrathin-film photovoltaic devices. These devices exhibit excellent photovoltaic performance, superior flexibility, and low production cost. Layered MoS₂ deposited on p-Si establishes a built-in electric field at MoS₂/Si interface that helps in photogenerated carrier separation for photovoltaic operation. We propose an Al₂O₃-based passivation at the MoS₂ surface to improve the photovoltaic performance of bulklike MoS₂/Si solar cells. Interestingly, it was observed that Al₂O₃ passivation enhances the built-in field by reduction of interface trap density at surface. Our device exhibits an improved power conversion efficiency (PCE) of 5.6%, which to our knowledge is the highest efficiency among all bulklike MoS₂-based photovoltaic cells. The demonstrated results hold the promise for integration of bulklike MoS₂ films with Si-based electronics to develop highly efficient photovoltaic cells

Front-contact passivation through 2D/3D perovskite heterojunctions enables efficient bifacial perovskite/silicon tandem solar cells

Abstract Understanding the effects of X‐rays on halide perovskite thin films is critical for accurate and reliable characterization of this class of materials, as well as their use in detection systems. In this study, advanced optical imaging techniques are employed, both spectrally and temporally resolved, coupled with chemical characterizations to obtain a comprehensive picture of the degradation mechanism occurring in the material during photoemission spectroscopy measurements. Two main degradation pathways are identified through the use of local correlative physico‐chemical analysis. The first one, at low X‐Ray fluence, shows minor changes of the surface chemistry and composition associated with the formation of electronic defects. Moreover, a second degradation route occurring at higher fluence leads to the evaporation of the organic cations and the formation of an iodine‐poor perovskite. Based on the local variation of the optoelectronic properties, a kinetic model describing the different mechanisms is proposed. These findings provide valuable insight on the impact of X‐rays on the perovskite layers during investigations using X‐ray based techniques. More generally, a deep understanding of the interaction mechanism of X‐rays with perovskite thin films is essential for the development of perovskite‐based X‐ray detectors and solar for space applications

Toward Stable Monolithic Perovskite/Silicon Tandem Photovoltaics: A Six-Month Outdoor Performance Study in a Hot and Humid Climate

Perovskite/silicon tandem solar cells are emerging as a high-efficiency and prospectively cost-effective solar technology with great promise for deployment at the utility scale. However, despite the remarkable performance progress reported lately, assuring sufficient device stability-particularly of the perovskite top cell-remains a challenge on the path to practical impact. In this work, we analyze the outdoor performance of encapsulated bifacial perovskite/silicon tandems, by carrying out field-testing in Saudi Arabia. Over a six month experiment, we find that the open circuit voltage retains its initial value, whereas the fill factor degrades, which is found to have two causes. A first degradation mechanism is linked with ion migration in the perovskite and is largely reversible overnight, though it does induce hysteretic behavior over time. A second, irreversible, mechanism is caused by corrosion of the silver metal top contact with the formation of silver iodide. These findings provide directions for the design of new and more stable perovskite/silicon tandem