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In the current scenario, COVID-19 has created a havoc negative impact on the lives of the people, which have triggered the research interest on the design and development of sensitive, low cost and power-efficient sensors for detecting a wide variety of biomolecules. Here, a novel hetero dielectric (HD) hetero material (HM) Bio-RFET based sensor is proposed which works as n or p MOSFET and n or p TFET and hence, is capable to sense the biomolecules through label-free dielectric modulation technique. Without labelling expenses, this biosensor detects a number of biomolecules present in human body as and when kept in a nano cavity. The dielectric polarization within the nanocavity due to the presence of foreign biomolecules under the influence of an electric field causes a variation in drain current. In this paper (SiO2 + TiO2) and AlGaAs/Si based HD-HM-RFET is explored for biosensing applications and mole fraction optimization of AlGaAs is done to obtain better results for four FETs. Work function of 4.5 eV is used in over drain and source electrodes, while metal work function of 4.7 eV is used for gate electrode. Finally, we found that the proposed device possesses better sensing capability for varying dielectric constant (K = 20 to 80) and charge (−5 × 1011 to 1 × 1013 C/cm2) as compared to a (SiO2 + HfO2)-HM-RFET and Si based (SiO2 + TiO2)-RFET. Further, it is observed that n-(SiO2 + TiO2)-HM-TFET is the best among all FETs and has highest Id-Vgs sensitivity = 5.09 × 1013, ION/IOFF = 1.23 × 109, lowest SS = 20.3 mV/dec and Vth = 1.48 V.

Metal oxide nanoparticles (MONPs) such as TiO2 and ZnO have been engineered for various industrial manufacturing processes. Among MONPs, environmental exposure to ZnO nanoparticles may cause health concerns about their significant toxicity. This leads to a desire of efficient methods for their removal in the aqueous environment with facile detection. In this work, 3-aminopropyltriethoxysilane (APTES) was chosen to treat aqueous suspensions containing ZnO and other metal oxide nanoparticles. APTES first formed a thin surface layer on ZnO nanoparticles and continued in branching polymerization to link up with adjacent APTES-ZnO nanoparticles. Eventually, a web-like sediment settled down onto the bottom and was confirmed to be APTES-ZnO conjugation by FT-IR. A high removal efficiency over 99 % w of ZnO nanoparticles in aqueous suspension was attained using 2.0 % by volume of APTES. The sedimentation was selective towards ZnO nanoparticles due to electrostatic interaction with ZnO to form a sturdy condensation coagulate. Other MONPs (Al2O3, CaO, CeO2, CuO and TiO2) did not form any web-like sediment with APTES but could co-precipitate with the ZnO nanoparticles. Meso-tetra(carboxyphenyl)porphyrin (TCPP) could be added as an indicator to co-precipitate with the sediment, with its color changing from red purple to bright green during the formation of APTES-TCPP-ZnO sediment. A filter paper or membrane placed at the bottom greatly facilitated the disposal of all sediments at a low cost.

Silica nanoparticles (SNPs) have shown great applicability potential in a number of fields like chemical, biomedical, biotechnology, agriculture, environmental remediation and even wastewater purification. With remarkably instinctive properties like mesoporous structure, high surface area, tunable pore size/diameter, biocompatibility, modifiability and polymeric hybridizability, the SNPs are growing in their applicable potential even further. These particles are shown to be non-toxic in nature, hence safe to be used in biomedical research. Moreover, the molecular mobilizability onto the internal and external surface of the particles makes them excellent carriers for biotic and non-biotic compounds. In this respect, the present study comprehensively reviews the most important and recent applications of SNPs in a number of fields along with synthetic approaches. Moreover, despite versatile contributions, the applicable potential of SNPs is still a tip of the iceberg waiting to be exploited more, hence, the last section of the review presents the future prospects containing only few of the many gaps/research extensions regarding SNPs that need to be addressed in future work.

In this paper, we present a double gate JL-TFET based biosensor by varying the gate dielectric constant to detect various biomolecules through label-free detection technique. An investigation regarding properties and behavior device has been investigated with the help of Silvaco TCAD. It is observed that Junction less TFET has advantageous over JLFET and TFETdue to the absence of junctions. The proposed device shows reduced short channel effects, lower subthreshold swing along with a higher voltage gain. The detection of the biomolecule is done by varying the gate dielectric constant inside the cavity and different electrical parameters such as electric field, sensing current, threshold voltage and transconductance are observed. The change in the threshold voltage, drain current, transconductance has been used as the sensing metric to detect the sensitivity of the presented device for biomolecule detection. Biomolecule position inside the cavity have been investigated to find out their effect on sensitivity parameter.

Commercial polyethylene (PE) fiber-based masks are currently used as personal filters for protection against various microorganisms. Due to the coronavirus (SARS-CoV-2) pandemic of 2020, the use of masks has become the critical mechanism in reducing the spread. The PE mask filter uses a sieve (geometry) in a spider web fashion to filter out microorganisms using Van der Waals atomic forces. However, the non-geometrical part of the filtration process is not fully understood. In this work, we utilized luminescent ultra-small silicon nanoparticles, which are Si-H or/and Si-OH terminated to examine how the filter operates at a chemical level. The particles were sprayed onto the fiber network by an atomizer and we used scanning electron microscopy (SEM), optical microscope and fluorescence spectroscopy under UV radiation. The images and measurements clearly showed that the Si nanoparticles bonded to the PE fiber network. The results were analyzed in terms of chemical bonding between Si nanoparticle and fiber. Our findings suggest that the PE fibers could act as a chemical filter via hydrogen or hydrolysis-based bonding or via Si-C bonding, which is complementary to their physical filtration ability via the geometric sieve process. Graphic Abstract

TFET based label-free biosensors are fast, sensitive and more power efficient as compared to CMOS biosensors, which are prone to short channel effects (SCEs). However, literature is flooded with various TFET biosensors that have become the reason of dilemma for researchers during pandemic situations like COVID-19. Therefore, in this work, a physically doped (PD), charge plasma (CP) and electrically doped (ED) dielectric modulated (DM) TFET based label-free biosensors are compared, which cover almost the entire range of doping and junctionless devices. Also, we found that the ED based TFET biosensors provide better current sensitivities of 5.10 x 10(7), 4.77 x 10(8) and 7.11 x 10(8) for biomolecules with K=12, positive charge= 1 x 10(13) C/cm(2) and negative charge= -1 x 10(13) C/cm(2) respectively. Hence, ED-DM-TFET based biosensors can act as promising candidates to provide better detection and identification quality.

The most affected disease in recent years is Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-COV-2) that is notable as COVID-19. It has been started as a disease in one place and arisen as a pandemic throughout the world. A serious health problem is developed in the lungs due to the effect of this coronavirus. Sometimes it may result in death as a consequence of extensive alveolar damage and progressive respiratory failure. Hence, early detection and appropriate diagnosis of corona virus in patient’s body is very essential to save the lives of affected patients This work evolves a Silicon (Si) based label-free electrical device i.e. the reduced graphene oxide field-effect transistor (rGO FET) for SARS-CoV-2 detection. Firstly rGO FET functionalized with SARS-CoV-2 monoclonal antibodies (mAbs). Then the rGO FET characteristic response is observed to detect the antibody-antigen reaction of SARS-CoV-2 with different molar ranges. The developed GFET shows better performance towards the drain current and limit-of-detection (LoD) up to 2E-18 M. Therefore, we believe that an intense response was observed than the earlier developed devices and signifies impressive capability for subsequent implementation in point-of-care (PoC) diagnostic tests.

The present work investigates the effect of using olive pomace bottom ash, the by-product of the clay brick industry, as an additive in the manufacture of fired clay bricks. Furthermore, it aims to improve the properties of clay bricks by using naturally available materials and also to develop an innovative way of recycling the waste resulting from the brick firing process. Olive pomace bottom ash was added to clay with multiple proportions (0%, 5%, 10%, 15%, and 20%) by weight. Bricks were molded by compression at 6.5 MPa, using a hydraulic brick press machine, and fired in an industrial scale furnace. The physicochemical, mineral, and geotechnical properties of raw materials were identified to study raw materials’ effect on the final fired products’ performance. The quality of fired specimens was determined by bulk density, linear shrinkage, water absorption, porosity, compressive strength, and thermal conductivity. In fact, samples with 5% olive pomace ash represent the highest compressive strength level, 11.5 MPa, compared to 9.65 MPa of reference samples. On the other hand, additions up to 20% increase the brick sample’s porosity from 18.28% to 34% for the reference mixture and the brick incorporated with 20% of additive, respectively, and decrease the brick’s bulk density from 1522 kg/m3 to 1431 kg/m3 for the reference mixture and the brick incorporated with 20% of additive, respectively. The incorporation of ash also improves the thermal conductivity of brick specimens. Expressly, thermal conductivity went from 0.41 W/m.K to 0.33 W/m.K for the reference mixture and the brick incorporated with 20% of additive, respectively, showing 37% of gain in thermal insulating properties of brick. Unfortunately, the capillary water absorption coefficient increases to 28% when 20% of additive is incorporated, which is not desired in the properties of construction materials. ASTMC67-07a standards: 2003, recommend water absorption level less than 17% for bricks with moderate weathering resistance. It was concluded that the addition of olive pomace bottom ash should not exceed 10% since it can be helpful in fired clay brick production based on standards requirements, leading to remarkable ecological gains without a loss of brick’s performances.

In the current study, by employing first-principles computations, the adsorption behavior of letrozole (LET) was investigated on the pristine graphdiyne nanosheet (GDY) as well as Si-doped graphdiyne (SiGDY). According to the adsorption energy, charge transfer value, and the change in the bang gap energy, the tendency of the pristine GDY towards LET is insignificant. However, the interaction of LET with SiGDY was strong and the adsorption energy was approximately − 19.20 kcal/mol. In addition, the associated electrical conductivity with SiGDY increased by approximately 23.53 % following the adsorption of LET. The results show that SiGDY can be employed as an electronic sensor to detect LET. Furthermore, LET is detected by SiGDY in the water phase based on the magnitude of solvation energy. Finally, a considerable charge-transfer between LET and SiGDY is a precondition for the adsorption of the LET molecule with proper binding energies, which delivers the Si atoms with a significant positive charge.

Sugarcane bagasse ash is used as a pozzolan in concrete. Although studies on sugarcane bagasse ash blended concrete are available, investigation on the influence of different curing methods in the performance of bagasse ash and marble waste blended concrete is essential. Therefore, the present study focuses on the effect of eight types of curing methods on the strength and durability of bagasse ash and marble waste based concrete. Sugarcane bagasse ash (20 %) and marble waste (25 %) were used at their optimum levels as a pozzolan and fine aggregates in concrete. Compressive strength, water permeability, sorptivity and abrasive resistance of concrete for different curing methods were studied. River sand and crusher sand were used as primary fine aggregate. Strength and durability performance of concrete specimens was comparable for moist curing, jute bag curing and straw curing. Normal water curing is found to be beneficial than other curing methods. Water cured bagasse ash and marble waste blended specimens had higher strength (36 %) and lesser permeability (18.8 %) than ambient cured specimens. Although variations in the abrasive wear are observed in the SCBA and MW blended concrete specimens, it is lesser than the permissible limit of 10 mm.

A highly-sensitive remote temperature sensor based on Tamm resonance is proposed using a one-dimensional photonic crystal. The proposed structure is prism/Ag/Toluene/SiO2 /(PSi1/PSi2)N/Si. The transfer matrix method is used to discuss the interaction between the structure and the S-polarization of the incident radiation waves. We optimized the structure by studying the effect of the incident angle, the thickness of the first and second layers of the photonic crystal unit cell, the porosity of them, and the thickness of the toluene layer. High sensitivity, high signal-to-noise ratio, and very low resolution are achieved due to the coupling between the porous silicon photonic crystal properties and Tamm resonance that makes it very distinguished compared to previous works.

In this research work, a master batch (comprising of AA2024 alloy, Silicon Nitride (Si3N4) and Graphite particulates) was reinforced by Silicon-Carbide (SiC) ceramic particulates (0–6 wt.-%; at steps of 2%; i.e. four composites samples viz. ASC-0; ASC-2; ASC-4; ASC-6) with the aim of enhancing mechanical and sliding tribology performance. The semi-automatic stir-casting fabrication process was followed as per standard industrial practice in-order-to fabricate the sample plates of the said alloy composites as per design. Thereafter, the sample specimens were prepared via wire EDM cutting followed by polishing over emery paper; as per ASTM standard dimensions and various physical (density and void content), mechanical (tensile strength, flexural strength, impact strength, hardness etc.), sliding tribology performance (steady state sliding wear; ASTM G-99; Pin-on-Disc tribo-meter), thermal (thermal conductivity, Thermo-Gravimetric Analysis (TGA)); thermo-mechanical (Dynamic Mechanical Analysis (DMA)), fracture-analysis, X-ray diffraction (XRD) etc. characterisation were performed and discussed. In Part-1: Physical, mechanical and sliding tribology performances were discussed. The Taguchi design of experiment technique was employed for designing of experimental runs having input controlling parameters like sliding velocity (0.654–2.616 m/s), sliding distance (784.8–3139.2 m), normal load (5–50 N), reinforcement content (0–6 wt.-%) and environment temperature (20–50 °C). The worn surface morphology studies were performed to understand prevalent wear mechanism using Field Emission Scanning Electron Microscope (FESEM) along with Energy-dispersive X-ray spectroscopy (EDS) that reveals elemental composition and its dispersion on the surface. In Part-2: evaluation of characterizations like thermal, thermo-mechanical, fracture-analysis, X-ray diffraction (XRD) etc. were discussed in correlation with mechanical and sliding wear performance. In Part-3: the entire performance data are analysed using hybrid AHP-TOPSIS technique (an MCDM technique; computationally simple and easy to understand) in-order-to rank the composites formulations.

The scarcity of water, especially during the dry season, is the main factor influencing water consideration with unknown characteristics for mixing cement mortar and concrete. This study investigates Palm Oil Mill Effluent (POME) effects as mixing and curing water on the hardened cement matrix properties. The cement pastes were prepared with ordinary Portland cement, which was used as a binder. In contrast, Potable Water (PW) and POME were used separately for mixing cement and a mixture of cement and sand to produce cement paste and cement mortar, respectively. Two different mix ratios of cement: sand of 1:3 and 1:5 with the constant water-to-cement ratio of 0.5 were used to prepare the cement mortar. The PW and POME were also utilized as the liquid curing media for hardened cement mortar until the testing ages of 7, 14, and 28 days. Soundness, normal consistency, and setting times tests were performed to evaluate cement paste’s fresh properties, while unit weight and compressive strength tests to determine the hardened properties of cement mortar at different ages. The results showed that soundness, normal consistency, and setting times of cement paste with POME as mixing water were higher than that of PW. This indicates that POME exhibits the potential of serving as retarding admixture. The unit weights of mortar (1:3 or 1:5 mix proportion) with POME as mixing water were lower than those produced with PW as mixing water after curing in PW or POME for 28 days; but for the mortar with POME as mixing water, the unit weight was slightly higher when cured in POME than water at the same curing age. The mortar specimens with 1:3 mix proportions with PW as mixing and curing water had the maximum 28-day compressive strength values of 26.01 N/mm2, while a decrease of 20% was recorded when cured in POME. Further decrease in 28-day compressive strength values was recorded cement mortar with 1:3 mix proportions and POME as mixing water after being cured in PW and POME. A similar trend was observed for cement mortar with 1:5 mix proportion with POME as mixing water when cured in PW and POME, and PW as mixing water when cured in POME, compared with the cement mortar with PW when cured in PW for 28 days. The maximum strength reduction of 20% specified by the standard for cement composite or concrete at 28 days of curing for water from the questionable source was exceeded with the use of POME as mixing water. It can be concluded that POME is not suitable for mixing cement mortar.

High performance concrete (HPC) is produced in this study by utilizing the agriculture industry by-product. The usage of by-product helps to condense the disposal issues, ecological degradation and also makes the production of concrete economical. The raw sugarcane bagasse ash from sugarcane industry is processed to ensure the suitability with the properties of cement to be used in HPC. Sugarcane bagasse ash (SCBA) is used as binder in HPC as an alternative of ordinary Portland cement. The properties of the SCBA have been studied. Investigation were carried out experimentally on M 60 grade of high performance concrete blended with SCBA to assess the workability, strength and durability properties at different ages of curing. Three SCBA blended HPC specimens were tested for each trial and test. Test results indicate improved performance in strength and durability properties up to 15% substitution level of SCBA with ordinary Portland cement.

In this fast-growing technological world biosensors become more substantial in human life and the extensive use of biosensors creates enormous research interest among researchers to define different approaches to detect biomolecules. The FET based biosensors have gained a lot of attention among all because of its high detection ability, low power, low cost, label-free detection of biomolecules, and CMOS compatible on-chip integration. The sensitivity of the biosensor inversely proportional to device size since they detect low concentration yields quick response time. Although FET based biosensor is having a lot of advantages among others but the short channel effects (SCE’s) and the theoretical limitation on the subthreshold swing (SS > 60mv/dec) of the FET leads to restrict device sensitivity and also have higher power dissipation due to the thermionic emission of electrons. To avoid these problems researchers focus shifts to the new technology FET based biosensors i.e. TFET based biosensors which are having low power and superior characteristics due to Band to band tunneling of carrier and steep subthreshold swing. This manuscript describes the full-fledged detail about the TFET based biosensors right from unfolding the device evaluation to biosensor application which includes qualitative and quantitative parameters analysis study like sensitivity parameters and different factors affecting the sensitivity by comparing different structures and the mechanisms involved. The manuscript also describes a brief review of different sensitivity parameters and improvement techniques. This manuscript will give researchers a brief idea for developing for the future generation TFET biosensors with better performance and ease of fabrication.

A novel biochar, whose precursor is popped rice, was produced to remove oil pollution in water. Popped rice biochar is characteristic with large pores. When popped rice was carbonized at 300 °C, its oil absorption capacity for paraffin oil is up to 10.88 ± 0.51 g/g, being much higher than that of the original popped rice (4.03 ± 0.39 g/g). In order to improve the oil-water separation property of popped rice biochar to absorb oil selectively, epoxy resin was used as a binder to make superhydrophobic SiO2 coated on the surface of popped rice biochar. The water contact angle of superhydrophobic SiO2 / popped rice biochar is 153 ± 0.9°, and it has good oil-absorption capacity with low water-absorption ratio. As the oil-absorption material is environmentally friendly, it will be a good select for the removal of oil pollution.

Herein, abrasive wear characteristics of SiCp dispersed zinc-aluminum based composites have been analyzed under high-stress condition. The wear tests were conducted on a Pin-on-Disc machine at a constant linear velocity of 1.57 m/s in the applied load range of 1-7 N while the abrasive platform used is 600 grit emery paper. A matrix alloy was also characterized under identical conditions to assess the influence of the dispersoid (SiC) particle on the wear behaviour. Wear rate, frictional heating and friction coefficient are the focused parameters of the study. The base alloy used has a dendrite structure comprising of α-dendrites surrounded by an α + η eutectoid and metastable e phase in interdendritic regions. The composite shows similar features to those of the base alloy except the additional presence of the reinforcing SiC particles. The wear rate and friction coefficient decrease with increase in abrading distance while a reverse trend was observed in the case of frictional heating which gradually increases with the increase in abrading distance. Incorporation of SiC particles improves the wear resistance of the matrix alloy and increasing the percentage of SiC increases the frictional heating and reduces the friction coefficient of the test material. The wear mechanism has been understood through SEM examination of wear surface, subsurface, debris particles and degraded abrasive grit papers.

The northeast region is the main producer of melons in Brazil. Soils under melon cultivation in this region are mainly pH-neutral and sandy, and hence prone to respond to Si fertilization, but there are no studies investigating Si application and melon responses in such an important producing area. To address this, here we carried out a field experiment to evaluate the effects of applying a diatomaceous earth-based fertilizer to melon grown on a Si-depleted soil from northeastern Brazil. The yield, weight, number, and quality of fruits, as well as the accumulation of Si and nutrients in melon leaves were evaluated. We found that Si fertilizer application increased the number, weight, and tonnage of melon fruits. This improvement in yield was related to an enhanced Si and nutrient uptake (N, P, K, Ca, Mg, Fe, Mn and Zn) by melon plants with the addition of silicon. Applying Si to soil did not significantly improve the pulp thickness, pulp firmness or soluble solids of melon fruits, despite a trend towards increased pulp thickness and soluble solids. The benefits of Si application were clearly observed to melon grown in sandy soils of northeast Brazil, but careful dose recommendation must be observed to make the practice cost-efficient and sustainable.

The aim of this study is to present the advantages of artificial stone production from the sludge of stone cutting factories (SSCFs), which is a self-cleaning and low-cost process, in Lorestan province, Iran. The basic formulation of artificial stone is the sludge stone: 50 % of the weight (wt.%) of sludge stone is cement. 12 wt.%, 25 wt.%, and 7 wt.% of the cement consists of unsaturated polyester resin liquid (UPR), water, and, filler respectively. The filler itself is made up of micro-silica and different amounts of anatase TiO2-NP and ZnO-NP. Nanoparticles lead to hydrophobicity, the analysis of oil stains, the elimination of bad odor, the sterilization and self-cleaning of artificial stone. The production of artificial stone via this method is pressure-resistant, highly flexible, resistant to freezing and scrapes, lightweight, capable of being cut and formed with a low thickness, and self-cleaning compared to the natural stone.