Transfer Coefficient Research Articles

Preparation, characterization and super electrocatalytic sensing study of polyaniline@yttrium phosphate (PANI@Y(III)PO4) nanocomposite

Synthesis of Y(III) phosphate-functionalized polyaniline nanocomposite (PANI@Y(III)PO4) was achieved through sol–gel method. The synthesized PANI@Y(III)PO4 was characterized by various techniques including Fourier-transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM), Energy dispersive X-ray spectroscopy (EDX), X-ray diffraction spectroscopy (XRD), X-ray photoelectron spectroscopy (XPS), Thermogravimetric analysis (TGA)-Differential thermal analysis (TGA-DTA) and direct current (DC) electrical conductivity. Efficient employment for the nanocomposite as modifier glassy carbon electrode was characterized by electrochemical impedance spectroscopy (EIS) and cyclicvoltametry (CV). The modified electrode showed a powerful enhancing effect and great stability in electrochemical sensing of the heavy metal ion Pb(II), giving an anodic peak current with a formal potential of - 0.195 V in acetic solution. The electrochemical parameters of the proposed sensor such as exchange current density (ⅉ0), active surface area of PANI@Y(III)PO4 modified GCE (A), surface coverage (Γ) of Pb (II) on the surface of PANI@Y(III)PO4, transfer coefficient (α) and number of electrons (n) involved in the electro-reduction, were found to be 92.21 μA cm-2, 0.27 cm2, 3.24×10-7 mol cm-2, 0.26 and 1.6 ≈ 2, respectively. Two voltametric techniques namely CV and linear sweep voltammetry (LSV) studies exhibited that the anodic peak current was linearly dependent on the concentration of Pb(II) with a broad dynamic range of 2.85–199.92 μM and 2.85–62.85 μM, respectively. However, the LSV method showed the highest sensitivity (5.58 μA μM-1 Cm-2) and the lowest detection limit (0.04 μM).

Substantiating the pulse method for determining the time parameter of fire detectors with a thermoresistive sensing element

This paper substantiates the pulse method for determining the time parameter for fire detectors with a thermoresistive sensing element ‒ the time constant. The method is based on using the Joule-Lenz effect, which manifests itself when an electric current pulse passes through the thermoresistive sensing element of fire detectors. Thermal processes in such a sensing element are described by a mathematical model that belongs to the class of equations of mathematical physics. The solution to the differential equation of this class was derived using the Hankel integral transformation and is represented as a series relative to the Bessel functions. The resulting solution is used to construct a mathematical model of a thermoresistive sensing element in the form of a transfer function, which takes the form of the transfer function of the inertial link. To trigger the thermoresistive sensing element of fire detectors, a single pulse of electric current in the shape of a rectangular triangle is used. The integral Laplace transformation was applied to mathematically describe the response of a thermoresistive sensing element to the thermal effect of such a test influence. To obtain information about the time parameter of fire detectors with a thermoresistive sensing element, the ratio of its output signals is used, which are measured in the a priori defined moments. A two-parametric expression was built to determine the time parameter of fire detectors; a verbal interpretation of the pulse method to determine it was provided. The implementation of this method ensures the invariance of the time parameter of fire detectors with a thermoresistive sensing element relative to the amplitude of a single pulse of an electric current, as well as relative to the parameter that is included in its transfer coefficient.

The influence of toxic metals As, Cd, Ni and Pb on nutrients accumulation in Mentha piperita

Medicinal plants are, for a considerable part of the population, an important source of treatment for certain diseases. They contain essential nutrients for the human body such as magnesium, iron , and zinc. The present study shows the influence of the addition of As, Cd, Ni, Pb on mineral nutrients in different organs of Mentha piperita. The experiments were carried out in the laboratory for a period of three months (May-July). Mentha piperita plants were AsCd and AsCdNiPb exposed up to final concentrations corresponding to the soil intervention threshold according to Romanian Order no.756/1997 (25 mg/kg As, 5 mg/kg Cd, 150 mg/kg Ni and 100 mg/ kg Pb). Simultaneously with these experiments, a control experiment (M) was performed. To evaluate the effect of the addition of AsCd and AsCdNiPb on the accumulation and transfer of Ca, Cr, Cu, Mn, Mo, Fe and Zn, the transfer coefficient (TC), the translocation factor (TF), and the enrichment factor (EF) were calculated. A higher concentration of Ca, Cr, Cu, Fe, Mn, Mo, and Zn was observed especially in the mint root in the experiments in which AsCdNiPb was added compared to those in which only AsCd was added. The AsCdNiPb addition did not influence the translocation of micro and macronutrients from the root to the aerial (edible) parts of the plant. In the case of the AsCd, addition, the translocation of zinc from the root to the aerial parts (leaves and stem) of the plant was increased.

DETERMINATION OF THE AVERAGE WALL TEMPERATURE OF THE PLATE IN A RECUPERATIVE HEAT EXCHANGER WITH A CORRUGATED MESH INSERT

This article discusses the issue of determining the value the average wall temperature of the plate of a recuperative heat exchanger type “air-to-air” with a corrugated mesh insert based on the results processing the data of a physical experiment to determine the thermohydraulic characteristics such heat exchange surfaces. It has been established that the temperature fi eld of heat exchange surfaces of this type is nonuniform, depends on the conditions of heat exchange and hydraulic regimes of air fl ow. Therefore, the adoption of the arithmetic means value of the measured surface temperatures as the calculated average temperature of the heat exchanger wall entails signifi cant errors in the subsequent processing of experimental data and fi nal the values of the heat transfer coeffi cients, the values the Nusselt criterion and the criterion equations of heat transfer. It is proposed to determine the average value the wall temperature of the heat exchanger based on the results of measurements the wall’s temperatures, the estimate of the coordinates the center of distribution the results of measurements the wall temperatures, the equations of heat balance and heat transfer.

INTENSIFICATION AND STUDY OF HEAT TRANSFER AND FRICTION IN THE PLATE HEATING SURFACES OF THE KMS-2 AIR HEATER WITH A PRESSURE GRADIENT

A numerical study of heat transfer and friction in the heat exchanger channels in the presence of a variable pressure gradient is performed. The research was carried out in software complexes (Code_Saturne, Salome). The results of the validation of the research method are presented and they showed that the deviation of the numerical simulation results from the calculation data according to the known criterion equations is within the error of generalization of the experimental data by the criterion equations. According to the results of studies at Red=3000, Red=4177, Red=6000, it was found that the average value of the heat transfer coeffi cient of the channel of variable cross-section is up to 20 % higher than for the channel at dp/dx0. At the same time, the thermal-hydraulic effi ciency of the alternating channel (L=117 mm, l=58.5 mm, n=2) in the initial section at x =0...0.08 is lower than in the channel with dp/dx>0 by 26.7 %, and at x =0.08...1 it is higher by 5 ... 15 %, at dp/dx

Exploration of the Polarization Curve for Proton-Exchange Membrane Fuel Cells.

The polarization curve is the most important profile to evaluate the performance of proton-exchange membrane fuel cells (PEMFCs). To explore the important thermodynamic parameters and their correlation with the composition, fabrication, and operational settings, a comprehensive data set consisting of 446 polarization curves from 191 perfluorosulfonate and 255 sulfonated hydrocarbon-based PEMs is collected. Then, a Markov chain Monte Carlo simulation within the Bayesian frame provides higher than 93% confidence to extract six important thermodynamic parameters including open-circuit potential, the transfer coefficient, the current loss, the reference exchange current density, the internal resistance, and the limiting current density. An extreme gradient boosting algorithm affords a mean determinative coefficient of 0.89 to predict the whole polarization curve and a confidence of 94% to predict the peak power density (PPD). Both approaches to explore the polarization curve for PEMFCs show good robustness in the blind test. Overall, the PPD is positively correlated with the ion-exchange capacity of the polymer, operational temperature, and humidity and is negatively affected by internal resistance, membrane thickness, and the loading of the catalyst. The flow rate of fuels can effectively enhance them, while the increase of catalyst loading or fuel concentration shows deleterious impacts.

Detection of Acetylcholine at Nanoscale NPOE/Water Liquid/Liquid Interface Electrodes.

The interface between two immiscible electrolyte solutions (ITIES) has become a very powerful analytical platform for sensing a diverse range of chemicals (e.g., metal ions and neurotransmitters) with the advantage of being able to detect non-redox electroactive species. The ITIES is formed between organic and aqueous phases. Organic solvent identity is crucial to the detection characteristics of the ITIES [half-wave transfer potential (E1/2), potential window range, limit of detection, transfer coefficient (α), standard heterogeneous ion-transfer rate constant (k0), etc.]. Here, we demonstrated, for the first time at the nanoscale, the detection characteristics of the NPOE/water ITIES. Linear detection of the diffusion-limited current at different concentrations of acetylcholine (ACh) was demonstrated with cyclic voltammetry (CV) and i-t amperometry. The E1/2 of ACh transfer at the NPOE/water nanoITIES was -0.342 ± 0.009 V versus the E1/2 of tetrabutylammonium (TBA+). The limit of detection of ACh at the NPOE/water nanoITIES was 37.1 ± 1.5 μM for an electrode with a radius of ∼127 nm. We also determined the ion-transfer kinetics parameters, α and k0, of TBA+ at the NPOE/water nanoITIES by fitting theoretical cyclic voltammograms to experimental voltammograms. This work lays the basis for future cellular studies using ACh detection at the nanoscale and for studies to detect other analytes. The NPOE/water ITIES offers a potential window distinct from that of the 1,2-dichloroethane (DCE)/water ITIES. This unique potential window would offer the ability to detect analytes that are not easily detected at the DCE/water ITIES.

Influence of soil inorganic amendments on heavy metal accumulation by leafy vegetables.

The present study aims to assess the effect of four inorganic soil amendments, such as lime (CaCO3), red mud consisting of 75% hematite (Fe2O3), gypsum (CaSO4·2H2O), and Al oxide (Al2O3), of an alkaline heavy metal-contaminated soil. For this purpose, a pot experiment was conducted by physically mixing individual six subsamples of a soil sample collected from Thessaly area with four inorganic soil amendments along with two leafy plants, spinach and lettuce. Al oxide causes the maximum reduction of the water-soluble Cu concentration, as its concentrations is no longer detectable. The Cu availability index decreases when aluminum oxide was used. The use of gypsum and red mud caused almost equal reduction while the smallest decrease was caused by the use of lime. The Zn availability index decreased equally when aluminum oxide and gypsum were mixed with the soil sample. The highest reduction of Cu and Zn transfer coefficient (TC) was observed when the Al2O3 was used. In spinach, Zn TC reduction was 39.8% and Cu TC reduction was 41.0%. In lettuce, the addition of Al2O3 led to Cu TC reduction of over 37.3% and Zn TC reduction of up to 38.7%. Generally, Al2O3 nanoparticles may function as suitable sorbents for the removal of Zn and Cu from soil samples, with an increasing effectiveness in spinach rather than lettuce. Liming materials seem to increase the soil alkalinity and promote the complexation of soluble heavy metals with hydroxide ions leading to immobilization of heavy metals in soil and reduce their amount in leafy vegetables. Remediation of contaminated soils is considered necessary to reduce environmental risks and to achieve the means available to increase agricultural production of safe and quality food.

Investigation of Potential Recovery Rates of Nickel, Manganese, Cobalt, and Particularly Lithium from NMC-Type Cathode Materials (LiNixMnyCozO2) by Carbo-Thermal Reduction in an Inductively Heated Carbon Bed Reactor

Within the e-mobility sector, which represents a major driver of the development of the overall lithium-ion battery market, batteries with nickel-manganese-cobalt (NMC) cathode chemistries are currently gaining ground. This work is specifically dedicated to this NMC battery type and investigates achievable recovery rates of the valuable materials contained when applying an unconventional, pyrometallurgical reactor concept. For this purpose, the currently most prevalent NMC modifications (5-3-2, 6-2-2, and 8-1-1) with carbon addition were analyzed using thermogravimetric analysis and differential scanning calorimetry, and treated in a lab-scale application of the mentioned reactor principle. It was shown that the reactor concept achieves high recovery rates for nickel, cobalt, and manganese of well above 80%. For lithium, which is usually oxidized and slagged, the transfer coefficient into the slag phase was less than 10% in every experimental trial. Instead, it was possible to remove the vast amount of it via a gas phase, which could potentially open up new paths regarding metal recovery from spent lithium-ion batteries.

Performance evaluation of natural and forced convection indirect type solar dryers during drying ivy gourd: An experimental study

The performance investigation of natural and forced convection indirect type solar dryers was performed by drying ivy gourd. The natural convection setup was modified by fitting a trapezoidal duct and central processing unit fans run by photovoltaic panels to promote forced convection. The data from the experiment was used to estimate collector and dryer efficiencies, energies, effective moisture diffusivity, transfer coefficients, specific energy consumption and specific moisture extraction rate. The average actual heat supplied was 776.6 and 997.76 W for natural and forced convections, respectively. The average collector efficiency for the same was 62.56% and 77.2%, respectively. The average drying efficiency for the same was 6.62% and 7.8%, respectively. The average values of activation energy, mass transfer, heat transfer and diffusion coefficients were estimated to be 39.85 and 35.54 kJ/mol, 7.06 × 10−9 and 8.35 × 10−9 m2/s, 0.0033 and 0.0043 m/s, and 3.85 and 4.93 W/m2 K, respectively, for natural and forced convection setups, respectively. The specific energy consumption and specific moisture extraction rate were evaluated where forced convection setup gave the best results. The drying correlations were developed for mass transfer, heat transfer and diffusion coefficients. Uncertainty analysis was performed to check the authenticity of the results.

EVALUATION OF RISK ASSESSMENT FACTORS AMONG SELECTED METALS IN ROADSIDE GROWN CEREALS OF THE SUDAN SAVANNA ECOLOGY OF NIGERIA

Phytoaccumulation of metals (Cd, Cr, Cu, Pb, Zn) in roadside grown wheat and maize varieties ( Pavon-76, Siettecerros, Zea mays L. and Zea mays everta L.) and the toxicity and phytoremediation capability of the plants was investigated. Four sampling sites, roadside (SU 1, SU 3) and distant sites (SU 2 and SU 4) were selected by principle to represent the level of pollution near major traffic routes and were the reference sampling points. Whole plant metal levels of the four crops were determined using the multi-elemental technique- Energy Dispersive X-ray Fluorescent (EDXRF) and double beam AAS at A.B.U Zaria. Plant uptake factor (PUF), soil-plant transfer coefficient (TC) and translocation factor (TF) was computed for each metal. Pearson correlation analyses between the risk assessment factors of the metals were evaluated. Results revealed a positive significant (P<0.05) relationship between PUF/TC and PUT/TF for Cr and Zn in Pavon-76, PUF/TC for Cr and Zn in the two species of Zea mays L. and Cu in Siettecerros indicates atmospheric inputs and special ability or strong selective ability of each of the crops to accumulate certain metals. The inverse correlation between PUF/TC, PUF/TF and TC/TF among the metals indicates the proximity of SU 1 to the major highway, influence of traffic density, atmospheric inputs and geological material and a combination of other factors. This study reveals the potentialities of these varieties of Wheat and Maize which are terrestrial higher plants as accumulators of metallic elements and phytoremediators of roadside soil pollution

Electrochemical separation of La from LiCl-KCl fused salt by forming La-Pb alloys

To separate La from LiCl-KCl fused salt by forming La-Pb alloy, the electrochemical codeposition of Pb(II) and La(III) on inert W electrode and electroreduction of La(III) on liquid Pb were explored, respectively, using a group of electrochemical measurement methods. The formation mechanism reduction peak potentials of La-Pb intermetallics were obtained from the results of cycle voltammetry (CV), square wave voltammetry (SWV) and anodic stripping voltammetry (ASV). The kinetic data of La(III)/La (in Pb) couple on liquid Pb cathode, for instance, exchange current density, transfer coefficient, charge transfer resistance and activation energy, were studied by linear polarization and Tafel techniques. Moreover, constant potentials electrolysis (CPE) and constant current electrolysis (CCE) were conducted onliquid Pb cathode to recover La from fused salt. The electrolytic products checked by SEM-EDS and XRD were composed of LaPb3 phases.The maximum separation efficiency of La could reach 92.03% after CCE (0.15 A) for 7 h, which confirmed the feasibility of separating La from LiCl-KCl fused salt.

Electrochemical investigations-based on ZnO@Cu core–shell in presence of CTAB surfactant for 4-Chlorophenol

The electrochemical performance of 4-Chlorophenol (4CP) was studied using a cationic surfactant cetyltrimethylammonium bromide (CTAB) and zinc oxide @ copper core–shell nanoparticles ([email protected] core–shell NPs) incorporated in carbon paste electrode (CPE) i.e., poly(CTAB)/[email protected] core–shell NP’s/CPE. The toxic molecule 4CP was investigated in the real samples such as soil, water, vegetables, and fruit samples employing the square wave voltammetric technique (SWV). The poly(CTAB)/ [email protected] core–shell NPs/CPE was characterized as sensitive due to its superior sensing characteristics for the identification of the analyte 4CP. The sensor exhibited excellent catalytic features and peak current with the involvement of pH 7.0 of phosphate buffer solution (PBS) of strength 0.2M employing techniques of voltammetry such as cyclic voltammetry (CV) and square wave voltammetry (SWV). The electro-kinetic parameters like heterogeneous rate constant, effect of temperature, transfer coefficient, scan rate, activation energy, accumulation time, pH, and involvement of electrons in 4CP electro-oxidation of was investigated. For bare CPE, the peak current was noted to be 2.315μA with peak potential of 0.8559 V. For coreshell/CPE, the peak current was 5.642μA with peak potential of 0.7587 V and for CTAB/coreshell/CPE, the peak current was 12.02μA with the peak potential of 0.7217 V. The soil and water samples were showed peak potential at 0.7124 V for different concentrations of 4CP. The limit of detection and quantification was estimated to be 1.655 × 10−9 M and 5.517 × 10−9 M for 4CP.

Simulation of 3D Electrochemical Phase Formation: Mixed Growth Control.

Processes of nucleation and growth largely determine the structure and properties of thin films obtained by electrodeposition on foreign substrates. Theoretical aspects of the initial stages of electrochemical phase formation under constant and variable overpotentials are considered in this work. Simulation of multiple nucleation with mixed (charge transfer, and diffusion) controlled growth was performed for three cases (cyclic voltammetry, potentiostatic electrodeposition, and galvanostatic electrodeposition). The influence of the bulk concentration of depositing ions and the exchange current density at the electrolyte/nucleus interface on cyclic voltammograms (CVs), transients of current and overpotential, as well as the number and size of non-interacting new-phase nuclei was analyzed. It is found that, under galvanostatic conditions, the number of nuclei decreases as the concentration of depositing ions increases due to a more rapid decrease in overpotential. The proposed model was applied to determine the diffusion coefficient, exchange current density, and transfer coefficient considering the experimental CV.

Ambient Temperature Sodium Polysulfide Catholyte for Nonaqueous Redox Flow Batteries

Long-duration energy storage (LDES) systems are needed to enable widespread adoption of intermittent energy resources. Redox flow batteries (RFBs) are particularly well-suited for grid-leveling applications because the system’s energy and power densities can be independently scaled. Despite exciting recent progress in both aqueous and nonaqueous systems, a major limitation of RFBs remains their high cost. For LDES applications, developing high energy density electrolytes containing earth abundant active materials is critical to meet targets for installed energy capital costs.Na-based batteries containing sulfur cathodes are attractive for low cost, high energy batteries due to sulfur’s earth abundance and high capacity (e.g., 1,672 mAh/gS for complete reduction to Na2S). Notable examples of S electrodes for reversible Na storage include: (i) molten S (e.g., high temperature Na/S batteries commercialized by NGK Insulators, Ltd. and Tokyo Electric Power Company), (ii) S-based composites containing carbon matrices designed to mitigate dissolution of sodium polysulfides (Na2Sx) in liquid electrolytes, and (iii) RFB electrolytes containing soluble Na2Sx species.This presentation will describe recent work on Na-based biphenyl|polysulfide RFBs and will highlight the effects of soluble vs. insoluble reaction products on reversible capacity and cycling stability. Full cells exhibited stable capacities (up to 200 mAh/gS) with high coulombic efficiency (99.68 ± 0.40%) and negligible capacity fade in both static and flowing cell geometries. For the first time in nonaqueous RFBs, we report the use of 3-electrode galvanostatic AC impedance measurements to identify rate limiting processes in the system. These findings demonstrate that voltage losses are dominated by charge transfer at the cathode, and relevant kinetic parameters (i.e., exchange current density and transfer coefficients) were calculated through a Tafel analysis. In this study, Na+ ß” Al2O3 (BASE) was used as a prototypical membrane, but practical systems require development of low-cost, mechanically robust membranes with high ionic conductivity and minimal crossover. Acknowledgements This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and is sponsored by the U.S. Department of Energy through the Energy Storage Program in the Office of Electricity.

Transcriptome analysis reveals the molecular mechanism of boron deficiency tolerance in leaves of boron-efficient Beta vulgaris seedlings

Sugar beet (Beta vulgaris L.) has a high demand for B, and B deficiency inhibits normal growth and productivity. However, there is a lack of information on how B deficiency affects the growth of beet at the transcriptome level, and the factors that govern B utilisation efficiency. This study aimed to identify the genes differentially expressed under B deficiency and those that underlie the mechanisms of efficient B use in two sugar beet cultivars. Accordingly, B-efficient (H, KWS1197) and B-inefficient (L, KWS0143) sugar beet cultivars were used, and two levels of boron were employed in the hydroponic experiments: B0.1 (0.1 μM B, deficiency) and B50 (50 μM B, CK). The results showed that B deficiency inhibited leaf growth, significantly reduced B concentration and B transfer coefficient, and increased peroxidase (POD) activity and malondialdehyde and proline content. The transcriptome data showed that the B-efficient variety exhibited more differentially expressed genes than the B-inefficient variety. Metabolic pathways were the most critical pathways involved in the B deficiency response. The expression of POD, bHLH, WRKY transcription factors, and nodulin26-like intrinsic protein (NIP5;1) were upregulated in the KWS1197 variety. In conclusion, the KWS1197 variety had physiological advantages and a highly efficient B utilisation molecular mechanism, contributing to a high B deficiency tolerance. This study provides a theoretical basis for the adaptation mechanism to B deficiency in sugar beets.

Identifying Interindustry CO2 Emissions Transfer Structure Using Network Methods

People's production and life have been inseparable from the consumption of various products, which often directly or indirectly release CO2. As CO2 emissions can transfer among industries, the identification and classification of the industries that release CO2 directly or indirectly can contribute to curbing the CO2 emissions. This paper proposes an input-output-based methodology to measure CO2 emissions transfer caused by linkages between industries in an economy and constructs the network topology in terms of the remarkable coefficients of interindustry CO2 emissions transfer. We classify all industries according to the role played in the emissions transfer process, and the network is represented by a “Bow-Tie” structure. In the visualization expression, it is easy to find the star nodes and the transmission paths of CO2 emissions among industries. Finally, the method is applied to the case of China. Empirical results indicate that the method developed in this paper provides new tools for the study of industrial CO2 emissions theory.

Effect of Nanofluids on the Enhancement of Boiling Heat Transfer: A Review

Boiling heat transfer can play a vital role in the two-phase flow applications. The analysis of the boiling hat transfer enhancement is of importance in such applications and the enhancement can be mostly conducted by using various active and passive techniques. One type of passive techniques is the enhancement of heat transfer by nanofluids. This article presents an extensive review on the effect of different nanofluids on the enhancement of heat transfer coefficient (HTC) and critical heat flux (CHF) for both pool as well as flow boiling. Nanoparticles addition to a working fluid is done arbitrarily to improve the thermophysical properties which in turn improves heat transfer rate. Numerous works have been done in the studies on nanofluid boiling. Among various nanoparticles, the most frequently used nanoparticles are Al2O3 and TiO2. In the case of binary nanoparticles, the most commonly used combination is Al2O3 and TiO2. After reviewing the relevant literatures, it is found that for pool boiling, the maximum HTC is increased to 138% for TiO2 nanoparticles and the maximum CHF is increased to 274.2% for MWCNTs. Conversely, in flow boiling the maximum HTC is increased to 126% for ZnO nanoparticles and the maximum CHF increased to as 100% for GO nanoparticles. In addition, when two or more nanoparticles in succession or binary nanofluids are used the CHF in pool boiling increased up to 100% for Al2O3 and TiO2 as well as the CHF in flow boiling increased up to 100% for Al2O3, ZnO, and Diamond. Though the information of the coefficient of heat transfer and the critical heat flux varied for different nanofluids and vary from experiment to experiment for each of the nanofluids. This variation happens because the coefficient of heat transfer and the critical heat flux in boiling is dependent upon several factors.

EVALUATION OF LUNG FUNCTION AFTER SARS-COV-2 PNEUMONIA

TOPIC: Pulmonary Physiology TYPE: Original Investigations PURPOSE: To investigate the patients' lung function at 3 and 6 months after hospital discharge for Coronavirus Disease 2019 (COVID-19) pneumonia. METHODS: A prospective lung function assessment has been conducted with spirometry measurements, including lung volumes, lung diffusion capacity for carbon monoxide (DLCO) with alveolar volume (VA), and transfer coefficient (KCO) determination. Patients with a restrictive ventilatory defect or impaired DLCO were re-evaluated at 6 months with global spirometry and chest HRCT scan. RESULTS: 40 patients have been enrolled in the study. Among them, 19 (48%) had normal pulmonary function tests (group A), and 21 (52%) showed residual lung function abnormalities at 3 months after hospital discharge (group B). In group B, 4 patients (19%) had an isolated loss of lung volume (Subgroup B1), 13 patients (62%) had both lung volume, and DLCO decreased (Subgroup B2), and 4 patients (19%) had isolated reduction in DLCO (Subgroup B3). At the 6-month follow-up visit, in Subgroup B1, although all patients improved, only one normalized the total lung capacity (TLC). In Subgroup B2, TLC and DLCO increased significantly (p<0.01), but only 3 patients reached normal values. In Subgroup B3, DLCO improved for most patients, normalizing in 50% of them. Always at the 6-months follow-up visit, significant correlations between an internal chest HRCT scan severity score and TLC (r2=0.33;p<0.01) and DLCO (r2=0.32;p<0.01) has been found. CONCLUSIONS: Nearly 50% of patients recovered in the post-critical phase. Most of those with abnormal pulmonary function tests at the 3-months follow-up visit had an improvement at the 6-month evaluation, but only 29% reached normal values. CLINICAL IMPLICATIONS: In patients with previous COVID-19 pneumonia, lung function spontaneous recovery is faster at first. However, at 6-months after hospital discharge, this recovery process goes more slowly, leaving more than one-third of patients with abnormal lung function tests. DISCLOSURES: No relevant relationships by Francesca Cettolo, source=Web Response No relevant relationships by Manuela Ciarfaglia, source=Web Response No relevant relationships by Jordan Franz Giordani, source=Web Response No relevant relationships by Michele Guerini, source=Web Response No relevant relationships by Guido Levi, source=Web Response No relevant relationships by Nicla Orzes, source=Web Response No relevant relationships by Laura Pini, source=Web Response No relevant relationships by Alessandro Pini, source=Web Response No relevant relationships by Claudio Tantucci, source=Web Response No relevant relationships by Silvia Uccelli, source=Web Response

Mathematical modelling of a staged pulverized coal gasification using O2/CO2 mixtures

Conversion of pulverized coal in a two-stage gasifier is studied. When considering carbon capture power plants, mixtures of oxygen with carbon dioxide may be used as a gasification agent. Carbon dioxide is a gasification agent, so characteristics of the gasification process change significantly compared to gasification in oxygen-nitrogen mixtures. The conversion efficiency is determined by the thermophysical factor (change in the heat capacity of the gas mixture and transfer coefficients) and the concentration factor (increase in the concentration of the gaseous reagent). The ratio of primary and secondary fuel consumption determines the leading stage of the process. The influence of process efficiency on oxygen concentration is estimated in the range of 21–30 vol. %.