Essence Research Articles

Temperature adaptive passive daytime radiative cooling: The impact of their essential properties on energy performance of different building types

Passive daytime radiative cooling (PDRC) materials can reduce building cooling demands during hot periods but increase heating needs in colder times, known as heating penalties, limiting their practicality. Temperature adaptive (TA) materials offer a solution, yet optimal TA PDRC properties, such as changes in reflectivity or emissivity from high surface temperature (HST) to low surface temperature (LST) states and the switch temperature at which these changes occur, are under-researched. To address this, a wavelength-dependent PDRC model was coupled with EnergyPlus to identify the optimal reflectivity or emissivity in HST and LST states and determine the appropriate switch temperature. Results show that different reflectivity and emissivity values are needed for various climates to maximize TA PDRC benefits. Switch temperatures from 15 °C to 30 °C primarily affect cooling benefits with minimal impact on heating penalties. Additionally, the heating penalty and cooling benefit of TA PDRC vary across building types, requiring alignment between TA PDRC operational characteristics and HVAC systems to optimize advantages. Among building types, malls benefit the most from PDRC application.

DFT study of structural, electronic, optical and elastic properties of lead-free Bi based perovskites X2NaBiCl6 (X= K and Rb) with pressure

The pressure dependent structural, electronic, optical and mechanical properties of Bi-based cubic halide double perovskites, X2NaBiCl6 (X = K and Rb) are explored by implementing full-potential linearized augmented plane wave (FP-LAPW) method. At zero pressure, K2NaBiCl6 and Rb2NaBiCl6 posses indirect band gaps of 3.746 and 3.735eV, respectively and the band gaps decrease with increasing pressure for both compounds. The elliptical shape of charge density contours under high pressure ensured a strong covalent bonding between K/Rb and Cl atoms along (110) plane. We explored the essential optical properties for both compounds with different pressures and found a red-shift with increase in pressure. Furthermore, all the values of mechanical parameters, viz. elastic constants and moduli, Vickers hardness, Debye and melting temperatures are enhanced with increasing pressure. Due to suitable band gaps and appropriate mechanical parameters, both perovskites are proved as promising candidates in thermoelectric power generation and high temperature devices.

Preparation of bismuth ferric oxide nanoparticles for the microwave-induced photo-degradation of organic pollutants in greywater.

This work demonstrates a thorough investigation into the synthesis and characterization of bismuth ferric oxide (BFO) photocatalyst for microwave-induced photodegradation of organic pollutants in greywater. Microwave (MW) irradiation was executed to enhance the generation of reactive oxygen species, contributing to the catalytic effectiveness of the synthesized photocatalyst. Through an efficient ultrasound-assisted synthesis process, perovskite BFO nanoparticles with a rhombohedral crystal structure and a crystallite size of around 15nm were successfully manufactured. Comprehensive characterization employing various analytical techniques including X-ray diffraction (XRD), Energy Dispersive X-ray Analysis (EDAX), Fourier Transform Infrared and Raman Spectroscopy, UV-Visible Diffuse Reflectance Spectroscopy (UVDRS), photoluminescence spectroscopy, Scanning Electron Microscopy (SEM), and Brunauer-Emmett-Teller (BET) studies provided insights into the structural, elemental, spectral, optical, morphological, and surface area properties of the nanoparticles. The UV-vis spectroscopy and Tauc's plot were employed to elucidate the band structure of the photocatalyst, providing insights into its essential electronic properties for catalytic applications. With a narrow optical band gap of 2.13eV, the synthesized photocatalyst demonstrated suitability for optical applications and exhibited substantial catalytic activity in the microwave-induced photocatalytic degradation of greywater. Remarkably, it achieved a 93.5% reduction in total organic carbon (TOC) within 180min under moderate 50-W illumination. Refining process parameters through optimization studies notably augmented degradation efficiency. Scavenging investigations validated the efficient mineralization of total organic carbon content. Kinetic assessments provided mechanistic insights into improved catalytic activity of BFO, which was attributed to a changed band structure that allows for fast charge transfer across interfacial layers. Moreover, the stability and reusability of the BFO photocatalyst were assessed over five cycles, highlighting its potential practical application as an efficient and reusable photocatalyst for greywater treatment. These findings underscore the promising prospects of BFO in addressing environmental challenges and advancing sustainable wastewater treatment technologies.

Field-theory action for the constructive standard model

We introduce a field-theory framework in which fields transform under the little group, rather than the Lorentz group, specific to each particle type. By utilizing these fields, along with spinor products and the x factor, we construct a field-theory action that naturally reproduces the vertices of the constructive standard model (CSM). This approach eliminates unphysical components, significantly reduces the degrees of freedom compared to traditional field theory, and offers deeper insights into the power of constructive amplitudes. Our action is momentum-conserving, Lorentz-invariant, Hermitian, and nonlocal. We also discuss this as a framework for developing new constructive field theories, discussing their essential properties and potential applicability in renormalization theory and nonperturbative calculations. Published by the American Physical Society 2024

Studying a cylindrical moving boundary problem in ductal carcinoma in situ

In this paper, a mathematical model of ductal carcinoma in situ (DCIS) is considered as a moving boundary problem in cylindrical coordinates. Using the front-fixing technique, first, we transform the problem into a nonlinear parabolic problem on a fixed domain, and then some essential properties of the solution, such as the uniqueness of the solution, are shown. A numerical approach based on the finite difference method is established for solving the fixed domain problem. The solvability of the proposed finite difference method is proved, and the stability and convergence of the numerical solution are shown. For a test case problem, analytical and numerical results are compared to demonstrate the ability and effectiveness of the numerical method.

Interaction of complex particles: A framework for the rapid and accurate approximation of pair potentials using neural networks

Motivated by the limitations of conventional coarse-grained molecular dynamics for simulation of large systems of nanoparticles and the challenges in efficiently representing general pair potentials for rigid bodies, we present a method for approximating general rigid body pair potentials based on a specialized type of deep neural network that maintains essential properties, such as conservation of energy and invariance to the chosen origins of the particles. The network uses a specialized geometric abstraction layer to convert the relative coordinates of the rigid bodies to input more suitable to a conventional artificial neural network, which is trained together with the specialized layer. This results in geometric representations of the particles optimized for the specific potential. The network can be trained directly on scalar values to fit a model without explicit gradient and then used to efficiently evaluate the force and torque on the particles resulting from the potential. The concept is demonstrated with an atomistic interaction model for carbon nanotubes and the resulting model is compared with a common type of coarse-grained model optimized for the same potential, with even very small networks comparing favourably and larger networks achieving up to two orders of magnitude lower cost. The sensitivity to noise in the training data is investigated and the model is found to strongly reject noise up to 12.5% given a dataset of 107 samples. The performance of a proof-of-concept implementation is demonstrated on a variety of hardware, showing the models viability for large-scale simulations. Furthermore, generalization to soft bodies and potentials for polydisperse systems are discussed. Published by the American Physical Society 2024

OTIMIZAÇÃO DE MISTURAS DE CONCRETO PARA REDUÇÃO DE CUSTOS COM USO DE POZOLANA

Concrete is the primary source for the development of civil engineering projects. In Brazil, its use reaches approximately 40 million cubic meters per year. As a result, concrete production is a central element in civil engineering, being used in a wide range of applications, from foundations to large structures. However, the costs associated with concrete production represent a significant portion of the total costs of a project. Therefore, the search for methods that can reduce these costs without compromising the quality and durability of structures is of utmost importance for the sector. The main objective of this work is to explore effective methods for optimizing concrete mixtures using additives or applying alternative materials in order to guarantee the quality of the product, with the aim of improving its physical-mechanical and economic characteristics. To achieve this goal, the following specific objectives were defined: to analyze the physical and mechanical properties of different concrete formulations, to identify the main factors that influence concrete production costs, to develop optimization models for concrete mixtures based on economic and performance criteria, and to evaluate the technical and economic feasibility of the proposed solutions in case studies. During the development of the research, comprehensive literature reviews were carried out to understand the latest trends and practices related to concrete production. In addition, laboratory experiments were conducted to analyze the physical and mechanical properties of different concrete formulations, taking into account the influence of variables such as type of aggregate and the use of pozzolan as an additive to improve concrete. Based on the data researched and the tests developed, it was possible to present pozzolan as a satisfactory additive for addition to concrete, since it reduces production costs while maintaining the essential properties of concrete, such as compressive strength, durability and workability. And because it is a more sustainable material, it reduces environmental damage.

The Heating Under Micro Variable Pressure (HUMVP) Process to Decrease the Level of Saponin in Quinoa: Evidence of the Antioxidation and the Inhibitory Activity of α-Amylase and α-Glucosidase

To reduce the level of saponin while preserving essential nutrients and antioxidative properties in quinoa (Chenopodium quinoa), this study delves into the optimization of the HUMVP process and thoroughly examines its effects on antioxidation as well as its inhibitory influence on α-amylase and α-glucosidase. The optimal HUMVP conditions involved wetting quinoa grains with 6% water (pH = 6.0) and subjecting them to a 4 min treatment under 0.35 MPa pressure. The values of •OH, DPPH, and ABTS•+ scavenging rate of the extracts from the quinoa sample (named Q2HUMVP) treated under the optimum HUMVP process were 70.02, 87.13, and 50.95%, respectively. Furthermore, the treatment preserved 95.20% of polyphenols and 73.06% of flavonoids, while the saponin content was reduced to 23.13% of that in raw quinoa. Notably, Q2HUMVP extracts demonstrated superior inhibitory activity against α-amylase and α-glucosidase compared to dehulled quinoa samples. The inhibition exhibited by the quinoa sample extracts on α-amylase and α-glucosidase was found to be reversible.

Quality Characteristics and Essential Oil Properties of Thymus capitatus, Mentha piperita, and Sideritis cypria Dried under Different Conditions

The drying of medicinal and aromatic plants (MAPs) is one of the main preservation methods for these products that can prolong their shelf life, if performed properly. The current study aimed to examine the effects of different drying conditions (sun, shade, and oven drying at 42 °C) on the quality characteristics of Thymus capitatus, Mentha piperita, and Sideritis cypria; their essential oil (EO) yield; and their biological properties (antioxidant and antibacterial activities). According to the results of the current study, oven drying resulted in faster moisture loss for all investigated species and slightly darker products. For T. capitatus, sun drying resulted in higher EO carvacrol content, whereas EOs obtained from shade and oven drying (at 42 °C) presented high total phenolic content and great antimicrobial activity. For M. piperita, shade drying resulted in a higher EO yield and higher iso-menthone content, whilst the EO obtained from oven-dried mint plants presented great antibacterial activity against the investigated foodborne pathogens. S. cypria plants dried in an air-ventilated oven produced an EO rich in β-caryophyllene and α-pinene, which also presented great antioxidant and antibacterial activity. The findings of the current study indicate that traditional drying methods, such as sun and shade, can result in good-quality dried MAPs that can yield EOs with significant biological activities, along with minimum energy consumption and lower carbon dioxide production (lower environmental carbon footprint), as opposed to oven drying. However, the drying-process duration could be a limitation at the industrial scale.

Ultra‐Low Power Photosynaptic Devices Based on Persistent Photoconductivity‐Modulated SnO2

AbstractRealizing visual perception performance using robust metal oxide devices is highly desirable for brain‐inspired neuromorphic computing, visual prosthetics, and artificial intelligence. SnO2, a representative transparent semiconductor, has attracted considerable attention for its potential in ultraviolet photodetectors and photosynaptic devices operating in solar‐blind spectral ranges. This problem has been circumvented by lowering the electron concentration and reducing the persistent photoconductivity (PPC), one of the essential properties of photosynaptic devices. In this case, the electron concentration and PPC properties in SnO2 must be controlled independently. This paper reports the successful control of PPC in SnO2 by controllable addition of Zn and Sr ions, which act as acceptors to annihilate the charge carriers and as a reductant to form oxygen vacancies, respectively. Zn and Sr‐added SnO2 exhibits superior synaptic performance with low energy consumption, successfully imitating the biological synapses without a gate electrode. As a result, the PPC remains at about 40% even after 20 seconds of turning off the ultraviolet light, and energy consumption is reduced to 1–10 fJ, similar to energy consumption with biological synapses. A novel optical sensor that can receive analog signals is demonstrated using a photosynaptic device with Zn and Sr‐added SnO2 thin films.

Rigid propagation of visual motion in the insect’s neural system

In the pursuit of developing an efficient artificial visual system for visual motion detection, researchers find inspiration from the visual motion-sensitive neural pathways in the insect’s neural system. Although multiple proposed neural computational models exhibit significant performance aligned with those observed from insects, the mathematical basis for how these models characterize the sensitivity of visual neurons to corresponding motion patterns remains to be elucidated. To fill this research gap, this study originally proposed that the rigid propagation of visual motion is an essential mathematical property of the models for the insect’s visual neural system, meaning that the dynamics of the model output remain consistent with the visual motion dynamics reflected in the input. To verify this property, this study uses the small target motion detector (STMD) neural pathway — one of the visual motion-sensitive pathways in the insect’s neural system — as an exemplar, rigorously demonstrating that the dynamics of translational visual motion are rigidly propagated through the encoding of retinal measurements in STMD computational models. Numerical experiment results further substantiate the proposed property of STMD models. This study offers a novel theoretical framework for exploring the nature of the visual motion perception underlying the insect’s visual neural system and brings an innovative perspective to the broader research field of insect visual motion perception and artificial visual systems.

The essence of soil and soil formation in accordance with soil water regime

The obtaining of new data on the transformation of parent materials into soil and on soil as a set of essential properties is provided on the basis of previously conducted fundamental studies of soils formed on loess-like loams in Belarus (15,000 numerical indicators). The study objects are autochthonous soils of uniform granulometric texture. The basic properties without which soils cannot exist are comprehensively considered. Interpolation of factual materials is given, highlighting the essential properties of soils. Soil formation is analyzed as a natural phenomenon depending on the life activity of biota and the water regime. Models for differentiation of the chemical profile and bioenergy potential of soils are presented. The results of the represented study interpret the available materials taking into account publications on the biology and water regime of soils over the past 50 years into three issues: the difference between soil and soil-like bodies; the soil formation as a natural phenomenon of the mobilization of soil biota from the energy of the sun, the atmosphere, and the destruction of minerals in the parent materials; and the essence of soil as a solid phase and as an ecosystem. The novelty of the article study is determined by the consideration of the priority of microorganisms and water regime in soil formation, chemical-analytical identification of types of water regime, and determination of the water regime as a marker of soil genesis.

KEDUDUKAN PEMIKIRAN KI HADJAR DEWANTARA DALAM FILSAFAT PENDIDIKAN

Ki Hadjar Dewantara is a central figure in education in Indonesia. His various thoughts were able to provide awareness to society during the Dutch colonial era, which did focus on education that was more oriented toward work skills. Ki Hadjar Dewantara through his great determination to establish an educational institution named "Taman Siswa" to restore the essence of education which gives the principle of independence. Education is also intended to help the growth and development of students so that students are active and able to realize all the competencies that exist in each individual student. This research seeks to find Ki Hadjar Dewantara's views regarding the concept of education and to see the position of Ki Hadjar Dewantara's thoughts regarding education in the structure of the philosophy of education. This study uses a qualitative method with a philosophical hermeneutic approach. The results of this study indicate that Ki Hadjar Dewantara's thoughts regarding the concept of education are more oriented toward the educational philosophy of essentialism, existentialism, progressivism, and perennials. So that in this context the idea of ​​Ki Hadjar Dewantara does not only rely on one school of educational philosophy, but is eclectic in nature, which means it combines several schools of educational philosophy which do not contradict one another but use positive principles from each school of philosophy. education and pay attention to the culture of Indonesian society.

Investigating the pH-Dependence of Gelation process in Chitosan-glutaraldehyde Hydrogels with Diffusing Wave Spectroscopy

The gel time of functional hydrogels is an essential property that dictates their utility in various applications. To accurately assess this parameter, the chitosan-glutaraldehyde hydrogels were characterized here using two complementary analytical tools, rotational rheometer, and diffusing wave spectrometer (DWS). Rotational rheometers are widely used to continuously monitor the macro-mechanical properties of hydrogels during the gelation process. By observing the modulus change curve, one can gain insights into the instantaneous changes occurring within the gel network. This method provides a direct measurement of the gel's mechanical strength; however, it involves applying external forces to the sample, which may introduce artifacts such as measurement lag and potential sample deformation or destruction. Results of this study indicated that the application of external force during rotary rheometer measurements disrupted the gelation process. In contrast, DWS detected alterations in the microstructure by measuring light diffusion, allowing to track microstructural changes post-crosslinking, and curing without the interference of external stress. Thus, DWS offers a non-invasive approach to studying gelation as it detected the Brownian motion of particles within the hydrogel by monitoring the diffraction of light, thereby providing undisturbed dynamic information about the gel's behavior. The DWS technique is particularly useful for tracking microstructural changes that occur during hydrogel crosslinking and curing, without altering the gel's native state. An additional advantage of DWS is its ability to investigate the pH effect on gelation. By measuring changes in gelation time as a function of pH, we could achieve precise control over the gelation process. This fine-tuning of gelation kinetics is crucial for applications that require rapid or delayed gelation, offering a level of precision that is difficult to match with traditional rheological methods.

Improving essential oil production and antioxidant properties of Carum copticum L. by titanium dioxide nanoparticles and light spectrum interaction under hydroponic conditions

Improving essential oil production and antioxidant properties of Carum copticum L. by titanium dioxide nanoparticles and light spectrum interaction under hydroponic conditions

Mechanical-electric response characteristics of 1–3 connectivity pattern cement-based piezoelectric composite sensors with varying functional phase parameters under impact loading

In this study, 1–3 connectivity pattern cement-based piezoelectric composites (CPCs) and cement-based piezoelectric composite sensors (CPCSs) with varying functional phase parameters were developed. The essential properties of the CPC specimens were systematically characterized. Additionally, the mechanical-electric response characteristics of the CPCS specimens under impact loading were examined using the split Hopkinson pressure bar (SHPB) technique. The results indicate that the piezoelectric constant (d33) of the CPC specimens increases with higher functional phase volume ratios and greater composite thickness. Under impact loading, both stress and electric displacement showed similar response patterns, demonstrating a strong force-electric coupling. Furthermore, within the experimental range, the electric displacement of the CPCS specimens increased with strain rate, indicating their potential for real-time monitoring of dynamic responses under varying impact conditions.

Facilitating and restraining virus infection using cell-attachable soluble viral receptors

SARS-CoV-2 uses the receptor binding domain (RBD) of its spike protein to recognize and infect host cells by binding to the cell surface receptor angiotensin converting enzyme 2 (ACE2). The ACE2 receptor is composed of peptidase domain (PD), collectrin-like domain, transmembrane domain, and short cytoplasmic domain, and may exist as a dimer on cell surface. The RBD binding site is located atop of the ACE2 PD, but the involvement of other domains in virus infection is uncertain. We found that the ACE2 PD alone, whether anchored to cell membrane via a glycosylphosphatidylinositol anchor or attached to another surface protein, is fully functional as a receptor for spike-mediated cell fusion and virus infection. However, for ACE2 to function as the viral receptor, the RBD binding site must be positioned in close proximity to the cell membrane. Elevating the surface height of ACE2 using long and rigid protein spacers reduces or eliminates cell fusion and virus infection. Moreover, we found that the RBD-targeting neutralizing antibodies, nanobodies, and de novo designed miniprotein binders, when present on cell surface, also act as viral receptors, facilitating cell fusion and virus infection. Our data demonstrate that RBD binding and close membrane proximity are essential properties for a receptor to effectively mediate SARS-CoV-2 infection. Importantly, we show that soluble RBD-binders can be engineered to make cells either susceptible or resistant to virus infection, which has significant implications for antiviral therapy and various virus-mediated applications.

Hydroponic Cultivation of Spices and Aromatics: Techniques, Benefits and Challenges

The global shift towards urbanization, with 55% of the population residing in urban areas and an anticipated rise to 68% by 2050, presents challenges to traditional farming. The increasing world population, further intensifies the strain on available agricultural land due to urban expansion. Climate change combines with these issues, make conventional cultivation more challenging. Alternative agricultural practices, such as hydroponics, gain significance in addressing these concerns. Aromatic and spices have been used for centuries for their medicinal and culinary properties. They contain various essential oils, flavonoids, and other phytochemicals responsible for their distinctive flavour and aroma, as well as their health benefits. The rising global demand for natural products from herbs and spices has led to its market growth. Hydroponics, a technology for cultivating plants in nutrient solutions with or without an artificial medium such as sand, gravel, vermiculite, rockwool, peat moss, coir or sawdust, offers a promising solution. This paper explores the potential of hydroponic cultivation for planting material production, enhancing the yield, nutritional composition, essential oil content and medicinal properties of various spice and aromatic crops, including black pepper, saffron, ginger, garlic, coriander, mint, celery, fenugreek, parsley, thyme, rosemary, green mustard, basil and others. The main challenges in hydroponic production of these crops include high initial investment, precise monitoring and lack of technical knowledge. Hence by reviewing recent literature, this paper aims to provide insights into the classification of hydroponics and its different techniques, benefits and challenges of hydroponic cultivation, various growing media and nutrient solutions used, types of hydroponics utilized and their purposes in the production of diverse herbs and spices. Embracing hydroponic techniques could contribute to sustainable agricultural practices, particularly in urbanized environments where traditional farming faces constraints.

Voxel Interface Control in Multimaterial Extrusion 3D Printing.

Interfaces are crucial in natural and engineered systems, dictating essential biological, ecological, and technological properties that augment performance, functionality, and user experience. Yet, achieving precise interfacial control poses significant challenges in both conventional and additive manufacturing, where scalability constraints impede the controlled deposition of quasi-2D layers within 3D objects. This paper introduces Voxel-Interface 3D Printing (VI3DP), which enables comprehensive control over extruded voxel interfaces irrespective of the printhead diameter that conventionally dictates feature size. Various optical, mechanical, and electrical functionalizations, attaining interface thicknesses up to three orders of magnitude smaller than the voxel size are reported. Notable applications include encoding data in soft matter through fluorescent interfaces, creating tight fits and movable mechanisms through non-adhesive interfaces, fabricating bio-inspired composites with tailored failure modes, and developing a single filament capacitive touch sensor. VI3DP opens new avenues for enhanced functionality and efficiency across multiple fields, including biomedical technology, electronics, optics, andnanotechnology.

Fanya Juu terraces improve soil properties of cultivated land in erosion-prone semi-arid area of Ethiopia

Soil erosion is a major process that affect soil fertility and agricultural productivity. To reduce soil erosion by water, physical soil and water conservation measures such as Fanya juu have been widely introduced. However, the study on the performance of those measures against its target is limited. Objective of this study was to assess the effects of physical soil and water conservation (SWC) measures (e.g., Fanya juu) on selected soil physico-chemical properties. Soil samples were collected at 0–20 cm depth of fields treated with Fanya juu and non-treated (without any physical SWC) and analyzed following standard laboratory procedures. Paired sample t-test and one-way ANOVA were used to analyze data. The results of the analysis revealed that clay, silt, sand, soil pH, soil organic carbon (SOC), total nitrogen (TN), available phosphorous (Pav.), and available potassium (Kav.) differed significantly (p < 0.05) between 8-years conserved and non-conserved land. This could be due to the positive effect of conservation measures in reducing erosion. In addition, in the intra- Fanya juu areas clay, sand, Kav., TN, and SOC were significantly varied (p < 0.05), with greater clay, SOC and nutrients at above Fanya juu (deposition area) than below Fanya juu (loss zone), which can be due to the downward movement of organic matter and surface soil and the protection ability of Fanya juu against erosion. In erosion-prone areas, lacking physical SWC measures could degrade essential soil properties as compared to farm fields with physical SWC measures. The spatial variation in intra-Fanya juu area should be amended by integrating additional soil fertility management practices for better effect.