Discussion on the impacts of real inertia of the wind turbine which is prevailing naturally and artificially controlled because the inertia of wind turbine is not consistent due to wind speed, the ...speed of the turbine and the torque of the turbine. Nowadays, the preservation of natural resources are becoming more important to replace the conservation energy sources due to global warming and environment changing etc. Therefore, so many techniques are taken to control the wind turbine output according to the variable wind speed. In this research work, IG wind turbine and DFIG wind turbine are used to accumulate the frequency deviation and wind turbine rotor speed using a PI controller for an only DFIG turbine named speed controller. There is also a comparison between the fixed speed wind turbine and the variable wind turbine to control the inertial impact of the variable speed of the turbine rotor at the variable wind speed.
Clinical studies of chloroquine (CQ) and hydroxychloroquine (HCQ) in COVID-19 disease reported conflicting results. We sought to systematically evaluate the effect of CQ and HCQ with or without ...azithromycin on outcomes of COVID-19 patients.
We searched multiple databases, preprints and grey literature up to 17 July 2020. We pooled only adjusted-effect estimates of mortality using a random-effect model. We summarized the effect of CQ or HCQ on viral clearance, ICU admission/mechanical ventilation and hospitalization.
Seven randomized clinical trials (RCTs) and 14 cohort studies were included (20 979 patients). Thirteen studies (1 RCT and 12 cohort studies) with 15 938 hospitalized patients examined the effect of HCQ on short-term mortality. The pooled adjusted OR was 1.05 (95% CI 0.96-1.15, I2 = 0%). Six cohort studies examined the effect of the HCQ+azithromycin combination with a pooled adjusted OR of 1.32 (95% CI 1.00-1.75, I2 = 68.1%). Two cohort studies and four RCTs found no effect of HCQ on viral clearance. One small RCT demonstrated improved viral clearance with CQ and HCQ. Three cohort studies found that HCQ had no significant effect on mechanical ventilation/ICU admission. Two RCTs found no effect for HCQ on hospitalization risk in outpatients with COVID-19.
Moderate certainty evidence suggests that HCQ, with or without azithromycin, lacks efficacy in reducing short-term mortality in patients hospitalized with COVID-19 or risk of hospitalization in outpatients with COVID-19.
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In this study, an alternative precursor for production of activated carbon was introduced using dragon fruit (Hylocereus costaricensis) peel (DFP). Moreover, KOH was used as a ...chemical activator in the thermal carbonization process to convert DFP into activated carbon (DFPAC). In order to accomplish this research, several approaches were employed to examine the elemental composition, surface properties, amorphous and crystalline nature, essential active group, and surface morphology of the DFPAC. The Brunauer-Emmett-Teller test demonstrated a mesoporous structure of the DFPAC has a high surface area of 756.3 m2·g−1. The cationic dye Methylene Blue (MB) was used as a probe to assess the efficiency of DFPAC towards the removal of MB dye from aqueous solution. The effects of adsorption input factors (e.g. DFPAC dose (A: 0.04–0.12 g·L−1), pH (B: 3–10), and temperature (C: 30–50 °C)) were investigated and optimized using statistical analysis (i.e. Box–Behnken design (BBD)). The adsorption kinetic model can be best categorized as the pseudo-first order (PFO). Whereas, the adsorption isotherm model can be best described by Langmuir model, with maximum adsorption capacity of DFPAC for MB dye was 195.2 mg·g−1 at 50 °C. The adsorption mechanism of MB by DFPAC surface was attributed to the electrostatic interaction, π-π interaction, and H-bonding. Finally, the results support the ability of DFP to be a promising precursor for production of highly porous activated carbon suitable for removal of cationic dyes (e.g. MB).
Salinity stress is one of the most destructive non-biological stresses in plants that has adversely affected many agricultural lands in the world. Salinity stress causes many morphological, ...physiological, epigenetic and genetic changes in plants by increasing sodium and chlorine ions in the plant cells. The plants can alleviate this disorder to some extent through various mechanisms and return the cell to its original state, but if the salt dose is high, the plants may not be able to provide a proper response and can die due to salt stress. Nowadays, scientists have offered many solutions to this problem. Nanotechnology is one of the most emerging and efficient technologies that has been entered in this field and has recorded very brilliant results. Although some studies have confirmed the positive effects of nontechnology on plants under salinity stress, there is no the complete understanding of the relationship and interaction of nanoparticles and intracellular mechanisms in the plants. In the review paper, we have tried to reach a conclusion from the latest articles that how NPs could help salt-stressed plants to recover their cells under salt stress so that we can take a step towards clearing the existing ambiguities for researchers in this field.
•NPs can alleviate salt stress in plants.•NPs improved the plant growth and photosynthesis under salt stress.•NPs reduced the oxidative stress in plants under salt stress.•Effect of NPs under salt stress varies with size, types, doses, exposure time, plants species.•Interaction of NPs at intracellular levels in salt stressed plants is lacking.
Silicon (Si) is the second richest element in the soil and surface of earth crust with a variety of positive roles in soils and plants. Different soil factors influence the Si bioavailability in ...soil-plant system. The Si involves in the mitigation of various biotic (insect pests and pathogenic diseases) and abiotic stresses (salt, drought, heat, and heavy metals etc.) in plants by improving plant tolerance mechanism at various levels. However, Si-mediated restrictions in heavy metals uptake and translocation from soil to plants and within plants require deep understandings. Recently, Si-based improvements in plant defense system, cell damage repair, cell homeostasis, and regulation of metabolism under heavy metal stress are getting more attention. However, limited knowledge is available on the molecular mechanisms by which Si can reduce the toxicity of heavy metals, their uptake and transfer from soil to plant roots. Thus, this review is focused the following facets in greater detail to provide better understandings about the role of Si at molecular level; (i) how Si improves tolerance in plants to variable environmental conditions, (ii) how biological factors affect Si pools in the soil (iii) how soil properties impact the release and capability of Si to decrease the bioavailability of heavy metals in soil and their accumulation in plant roots; (iv) how Si influences the plant root system with respect to heavy metals uptake or sequestration, root Fe/Mn plaque, root cell wall and compartment; (v) how Si makes complexes with heavy metals and restricts their translocation/transfer in root cell and influences the plant hormonal regulation; (vi) the competition of uptake between Si and heavy metals such as arsenic, aluminum, and cadmium due to similar membrane transporters, and (vii) how Si-mediated regulation of gene expression involves in the uptake, transportation and accumulation of heavy metals by plants and their possible detoxification mechanisms. Furthermore, future research work with respect to mitigation of heavy metal toxicity in plants is also discussed.
•Root application of silicon (Si) improved soil physical and chemical properties that help in decomposition of organic matter.•Exogenous Si efficiently restricted the heavy metals (HMs) uptake and translocation within the plants.•Si improved the root morphology and competed with HMs for uptake in root cells and translocation to xylem vessels.•Si actively participates in plant growth with respect to all aspect under HM toxicity.
Polyethylene glycol (PEG)-based nanofluids possess several unique properties that make them suitable for various applications. To utilize them on an industrial scale, it is crucial to understand ...their flow characteristics in different processing equipment. This article presents an investigation of the boundary layer flow of viscoelastic nanofluids over a moving wedge and plate, utilizing the Burger model with Maxwell representation for heat and mass transfer characteristics. The nanofluids utilized in this study consist of Polyethylene glycol (PEG) as the base fluid, and multi-wall carbon nanotubes (MWCNTs) as nonmaterial with a nanoparticle volume fraction ranging from 0.05% to 0.5%. Experimental data were collected in the form of storage (elastic) and loss (viscus) moduli against angular frequency, and mathematical expressions were derived to model this data at various nanoparticle volume fractions. These expressions were then incorporated into the flow equations, which were solved subject to appropriate boundary conditions using analytical techniques. The resulting velocity and temperature profiles, under the influence of nanoparticle volume fraction, are presented graphically. Additionally, physical quantities such as velocity and thermal boundary layer thickness, displacement, and momentum thickness were calculated numerically and presented in tabulated form. The findings of this study indicate that increasing nanoparticle volume fraction results in a decrease in the velocity profile and an increase in the temperature profile.
Menadione sodium bisulfite (MSB) is a crucial growth regulator mediating plant defense response. MSB-mediated regulation of defense mechanisms in wheat under chromium (Cr) toxicity has not been ...reported in the literature. Therefore, the present study was undertaken to appraise the efficacy of exogenous MSB on circumventing Cr phytotoxic effects on wheat. We also compared the effects of water-soluble MSB with that of water-insoluble menadiol diacetate (MD). The levels used in the present investigation for MSB and MD were 100 and 200 mg L
−1
. Wheat plants grown in soil contaminated with 25 mg kg
−1
Cr in the form of K
2
Cr
2
O
7
showed a notable reduction in growth, chlorophyll molecules, relative water contents, grain yield, total soluble sugars, phenolics, flavonoids, ascorbic acid, activities of antioxidant enzymes (SOD, POD, CAT), and uptake of essential nutrients (K, P, and Ca). Cr toxicity caused a noticeable accretion in total free amino acids, proline, malondialdehyde, H
2
O
2
, O
2
•−
, relative membrane permeability, methylglyoxal contents, activities of enzymes (lipoxygenase, glutathione-
S
-transferase, and ascorbate peroxidase), nitric oxide and H
2
S contents, glutathione and oxidized glutathione contents, total Cr contents, and Cr
6+
and Cr
3+
accumulation. MSB application significantly reduced lipid peroxidation, ROS overproduction, methylglyoxal levels, total Cr contents, and maintained higher Cr
3+
:Cr
6+
ratio in aerial parts. Besides, Cr-mediated inhibition in essential nutrient uptake was significantly circumvented by exogenous MSB. Consequently, MSB enhanced wheat growth by lessening oxidative damage, total Cr contents in aerial parts, and strengthening antioxidant enzyme activities. MD was not effective in mediating defense responses in wheat under Cr toxicity.
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