Analysis of the benefits of adopting roof sandwich panels integrated with PCM versus PUR to mitigate energy costs and carbon dioxide emissions

The construction industry's thirst for power has skyrocketed on a global scale. A significant amount of this power is used for buildings' heating, ventilation, and air-conditioning needs (HVAC systems), which in turn ensure occupants' comfort. A sustainable future requires more zero-energy or green buildings to meet the massive global energy demand. This study explores the possibility of reducing air conditioning expenses while taking into account various roof systems referring to sheet panels integrated with thermal insulation or a phase change material. Within the context of the current investigation, four sheet panels made of acrylic, aluminium, galvanized iron, and polycarbonate were examined. In addition, aforementioned sheet panels were filled with either polyurethane (PUR) foam insulation or a form-stable phase change material of FS29, an organic and inorganic mixture. In order to ascertain the thermo-physical properties of FS29 PCM (in both its solid and liquid phases), as well as its latent heat, experiments were carried out. According to the findings, the roof with the acrylic PCM integrated roof (ACPIR) succeeds in the best annual air conditioning or energy cost savings (7.90 and 8.18 $/m2/year), the highest carbon emission mitigations (144.15 and 156.44 kg-CO2/year) and the shortest payback period (9 and 8.7 years), for India's composite and warm-humid climatic conditions

Enhancing flexural property and mesoscopic mechanism of cementitious tailings backfill fabricated with 3D-printed polymers

Backfill mining, one of the most common methods for removing hazardous tailings, is performed on cementitious tailings backfill (CTB), which can be employed to fully discard risky tailings while diminishing the ecological effect on the surface by delivering them underground voids as backfill material. By counting mechanized mining tools, the downward backfill hexagonal approach mining method is an effective way to exploit surrounding rock with poor properties. With this innovative extraction technique, it is crucial to guarantee the safety, productivity and cost control of a solid artificial false roof. To further strengthen the toughness and strength of CTB structures, two new 3D-printed polymer (3D-PP) models (i.e., Models 1 and 2) were constructed in this study. The fracture toughness and flexural strengths of CTB were explored via 3-point bending tests and scanning electron microscopy (SEM) observations. Lab testing results showed that 3D-PP application considerably enhanced the flexural/deflection properties of CTB. The bending strength of the CTB structures fabricated with 3D-printed polymers was 1.72 MPa, which indicates a major increase of 409% when compared with that of the control specimens (N-3D-PP). The highest deflection value was 17.6 mm, which also showed a significant increase in CTB structures. One can also interpret from the SEM–EDS results that CTB structures presented many CSH products, which escorted with major elements: O, Si, and Ca. Applying 3D-PP results in backfill with good toughness and ductility, while N-3D-PP reveals brittleness. Moreover, the deflection enhancement effect of Model 2 is much greater than that of Model 1. Finally, this study urges that the development of flexural properties and mesoscopic mechanisms of CTB be ensured by 3D-PP models, maintaining a decreased failure probability of mine fills

Optimization of clean-up in QuEChERS method for extraction of mycotoxins in food samples: A systematic review

Mycotoxins in food should be evaluated regularly. In order to determine the amount of mycotoxins in food, accurate extraction methods should be used. In this systematic review, the type of clean-up step in the QuEChERS method was considered in the preparation of food samples for the measurement of mycotoxins. Furthermore, the method of extraction was also investigated. The selected keywords in important databases were defined as QuEChERS, mycotoxin, analytical method, detection, evaluation, and food. 291 articles were the result of the search. The manuscripts that were optimized for cleanup were selected. About 80% of the studies identified mycotoxins in food with plant origin. In the extraction stage, the most used solvent was acetonitrile, which was acidified with formic acid or acetic acid. Clean-up was used in most of the studies. Usually two compounds, C18 and PSA, were used together or alone. PSA was more recommended for foods containing carbohydrates, starches, and pigments, and C18 for foods containing high fat

Impact of CdSeTe and CdSe film deposition parameter on the properties of CdSeTe/CdTe absorber structure for solar cell applications

In this study, the effect of depositing CdSeTe and CdTe layers at different substrate temperatures (STs) by evaporation in vacuum on the properties of the CdSeTe/CdTe stacks was investigated. First, CdSeTe layers in stack structure were grown at STs of 150 °C, 200 °C and 250 °C and then CdTe layers on the CdSeTe produced with the optimum temperature were coated at STs of 150 °C, 200 °C and 250 °C. The employing of STs up to 150 °C on both CdSeTe and CdTe films in CdSeTe/CdTe stacks demonstrated the presence of Te and/or oxide phases as well as the alloying, while more stable phase structures at higher temperatures. In the CdSeTe/CdTe stack, the increase in ST of CdSeTe promoted the alloying, while it weakened the alloy in which was applied in CdTe. It was concluded that under the applied experimental conditions, STs of 250 °C and 200 °C with the graded alloying structure, suitable absorption sites, more homogeneous surface morphology for potential solar cell applications would be more suitable for CdSeTe and CdTe, respectively. As a result, the application of ST to CdSeTe or CdTe in the stacks can be used as a tool to control the properties of the stack structure

The continuity in q of the Lupaş q-analogues of the Bernstein operators

The Lupas q-analogue Rn,q of the Bernstein operator is the first known q-version of the Bernstein polynomials. It had been proposed by A. Lupas in 1987, but gained the popularity only 20 years later, when q-analogues of classical operators pertinent to the approximation theory became an area of intensive research. In this work, the continuity of operators Rn,q with respect to parameter q in the strong operator topology and in the uniform operator topology has been investigated. The cases when n is fixed and n -> infinity have been considered. (c) 2022 Elsevier Inc. All rights reserved

Chemical and Biological Activities of Callistemon citrinus and Punica granatum

Abstract: Plants have great potential for researchers with their active ingredients. In the study, extracts of Callistemon citrinus (Brush bush) and Punica granatum (Pomegranate) bark plants were prepared at 2.5 and 5 concentrations. The antimicrobial activities of the extracts were investigated by the agar well method against various Gram negative, Gram positive bacteria and two Candida species. Anti Quorum sensing activity was investigated with Chromobacterium violaceum and Pseudomonas aeruginosa strains. In addition, its antioxidant properties were screened by the DPPH (1,1-Diphenyl-2-picrylhydrazil radical; C18H12N5O6) method. According to the findings obtained as a result of the study, it was seen that both plants were effective in terms of antimicrobial activity. Antioxidant property scans show that 2.5% concentration data is more successful than the data of 5% concentration extracts. As a result of the study, it was observed that the plants were rich in new antibiotic active substances and bioactive substances. Antibiotic resistance, which has increased rapidly in recent years, is one of the leading public health threats. Researchers are searching for alternative methods for new and effective antibiotics to combat resistance. Different methodologies such as quarum sensing have gained importance in the search for active substances. It was determined that antiquarum detection activity was especially high in pomegranate extract groups

Machine learning driven optimization and parameter selection of multi-surface HTS Maglev

This research aims to tackle the challenges posed by precise force measurement for high temperature superconducting (HTS) Maglev systems, including mechanical constraints, step motor limitations, and sensor resolutions. For this aim, six machine learning (ML) models namely Support Vector Machine (SVM), Gaussian Process Regression (GPR), Extreme Gradient Boosting (XGB), Long Short-Term Memory (LSTM), Extreme Machine Learning (EML), and Convolutional Neural Network (CNN) were developed to predict levitation force (Fz) and lateral force (Fx) based on process parameters including permanent magnet width (PMW), field cooling height (FCH), the movement in the z-axis (vertical distance), and the movement in the x-axis (lateral distance). Among six ML models, CNN emerged as the most accurate model, demonstrating smaller root mean square deviation (RMSD) without compromising correlation coefficients. Furthermore, an innovative process window approach was introduced to select process parameters that simultaneously meet the minimum value of Fz and maximum value of Fx, named β1 and β2, set at 90 N and 0 N, respectively. Within this window, PMW of 30 mm and z values less than 10 mm were found to be consistent for all FCH and x values. The novelty of this study is to formulate the optimisation problem in HTS Maglev using the developed ML model by addressing two specific objectives one of which focuses on maximizing Fz while ensuring Fx remains within a defined tolerance (β3), representing the minimum allowable ratio of the levitation force to the total force, and the second problem aims to maximize Fz while obtaining zero Fx. The optimum PMW, FCH, x, and z values were obtained at 30 mm, 30 mm, 4 mm and 5 mm, corresponding to Fz and Fx values of 224.2 N and -53.8 N for option 1. As for option 2, the process parameters were obtained as 28.6 mm, 25.9 mm, 0 mm, and 5 mm, corresponding to Fz and Fx values of 194.2 N and 0 N. It was obtained both experimentally and by the optimization that Fz reaches close its maximum as the Fx gains attractive character. Hence, it is expected that the outcomes of this study will significantly benefit the design of HTS Maglev systems and find valuable applications across various transportation engineering projects

Performance assessment of oxygenated CdS films-based photodetector

dS films were grown by thermal evaporation on glass substrates. After growth process, samples were oxygenated at 400 °C at various gas pressures for 5 mins employing rapid thermal process. The produced CdS films were used as photodetectors in blue light. X-ray diffraction results revealed that as-deposited CdS films had a wurtzite crystal structure with a satrong preferred orientation along (002) plane. The intensity of (002) peak increased by rising oxygen gas pressure to 2 atm and then decreased with further increase of oxygen gas pressure to 4 atm. Scanning electron microscopy analysis indicated that even though as-deposited CdS thin films included some aligned rod-like grains on an underlaying layer, oxygenation at various gas pressures changed the surface morphology of CdS films. CdS films oxygenated at a gas pressure of 2 atm exhibited the best transmittance value of 80% in the range of 600–1000 nm. It was calculated that band gap increased from 2.42 eV to 2.45 eV as CdS films were oxygenated at a gas pressure of 2 atm. Photoluminescence spectrum of as-deposited CdS films indicated two fundamental peaks located at 530 nm and an interval of 550–700 nm, corresponding to green and deep level emissions, respectively. Consequently, it was attained that CdS films oxygenated at a pressure of 2 atm had the optimized structural, morphological and optical results and therefore, this sample was further employed for photodetecting applications. From photocurrent-time curves, the best photodetecting performance was reached for CdS films-based device oxygenated at a gas pressure of 2 atm including rise time and fall time values of 22 ms and 25 ms, respectively. In addition, the maximum responsivity, detectivity and external quantum efficiency were found to be 23.7 mA/W, 4.75 × 108 Jones and 6.6 for the same photodetector, respectively

Pulmonary artery pseudoaneurysms in cannonball metastases

...

Addressing the looming epidemic of metabolic dysfunction-associated steatotic liver disease in Pakistan: A call for action

The term metabolic dysfunction-associated steatotic liver disease (MASLD), which evolved from its predecessor, nonalcoholic fatty liver disease (NAFLD),[1