Cp Values Research Articles

Composition of the Solvation Shell of the Selected Cyclic Ethers (1,4-Dioxane, 12-Crown-4, 15-Crown-5 and 18-Crown-6) in a Mixture of Formamide with Water at Four Temperatures

The solution enthalpy of 15-crown-5 and 18-crown-6 ethers in the mixture of formamide (F) and water (W) was measured at four temperatures: 293.15 K, 298.15 K, 303.15 K, 308.15 K. The standard molar enthalpy of solution, ΔsolHo, depends on the size of cyclic ethers molecules and the temperature. With increasing temperature, the values of ΔsolHo become less negative. The values of the standard partial molar heat capacity Cp,2o of cyclic ethers at 298.15 K have been calculated. The Cp,2o=f(xW) curve shape indicates the hydrophobic hydration process of cyclic ethers in the range of a high-water content in the mixture with formamide. The enthalpic effect of preferential solvation of cyclic ethers was calculated and the effect of temperature on the preferential solvation process was discussed. The process of complex formation between 18C6 molecules and formamide molecules is observed. The cyclic ethers molecules are preferentially solvated by formamide molecules. The mole fraction of formamide in the solvation sphere of cyclic ethers has been calculated.

Effects of unsteady stream on hydrodynamic behavior of flexible hydrofoil in semi-passive mode

The effects of unsteady stream on the hydrodynamic behavior of a flexible hydrofoil in the semi-passive mode are investigated in this study with the goal of improving power extraction. Specifically, the influences of flow velocity amplitude (λ), the frequency ratio (σ) between hydrofoil and flow velocity, and phase difference (ε) between the flow velocity and pitching motion of the hydrofoil are examined. The results reveal that σ has a significant effect on lift force and heaving velocity, thus severely affecting the average power coefficient (CP‾) and heaving response. The peak value of CP‾ is attained when σ = 2; this is attributed to the satisfactory synchronization between the flow velocity and heaving motion of the hydrofoil. Initially, CP‾ increases with ε until ε = 90°; then, it decreases as ε further increases. The equilibrium position of the heaving response is sensitive to both ε and λ. The relative relationship between the flow velocity and pitching motion is modified by ε, altering the evolution of the lift force, heaving velocity, vortex, and pressure distribution. Through comprehensive adjusting σ and ε according to λ, the hydrofoil encounters minimum incoming flow near the dead point. This is the key to improve power extraction.

Performance Characteristics of Savonius Wind Turbines With Variations Air Gaps in Supporting the Development of Renewable Energy

<pre><strong><em>To overcome the occurrence of an energy crisis in the future, an innovation / invention of energy that is environmentally friendly and energy sources will not run out in the future. Energy sources that are environmentally friendly and their potential when developed is very large, one of which is energy sources derived from wind energy.</em></strong> <strong><em>This study aims to determine the effect of wind speed on the performance of wind turbines. To find out the performance characteristics of wind turbines with variations in air gaps. The research method begins with the design / design of the wind turbine, then continues the manufacturing stage, the assembling and installation stage, the testing of tools and analysis, the tests carried out include testing the performance characteristics of the wind turbine. The parameters measured in this study are rotation, torque as well as calculating the kinetic power produced, TSR and CP. The test results conducted showed that the 200 mm air gap Savonius wind turbine with a value of CP = 0.02480-0.15658 had optimum work at low wind speeds (4 m / s). Meanwhile, the 170 mm airborne Savonius wind turbine with a value of CP = 0.00593-0.14668 has optimum work at high wind speeds (8 m / s to 9 m / s). </em></strong></pre><p><strong><em>Keywords- wind turbine savonius, air gap, coefficent of power.</em></strong><strong><em></em></strong></p>

Cultured rat aortic vascular smooth muscle cells do not express a functional TRPV1.

We showed previously that capsaicin, an active compound of chili peppers, can inhibit platelet-derived growth factor-induced proliferation in primary rat vascular smooth muscle cells (VSMCs). The inhibition of BrdU incorporation by capsaicin in these cells was revoked by BCTC, which might be explained by a role of TRPV1 in VSMCs proliferation. To further pursue the hypothesis of a TRPV1-dependent effect of capsaicin, we investigated TRPV1 expression and function. Commercially available antibodies against two different TRPV1 epitopes (N-terminus and C-terminus) were rendered invalid in detecting TRPV1, as shown: i) in western blot experiments using control lysates of TRPV1-expressing (PC-12 and hTRPV1 transfected HEK293T) and TRPV1-downregulated (CRISPR/Cas gene edited A10) cells, and ii) by substantial differences in staining patterns between the applied antibodies using fluorescence confocal microscopy. The TRPV1 agonists capsaicin, resiniferatoxin, piperine and evodiamine did not increase intracellular calcium levels in primary VSMCs and in A10 cells. Using RT qPCR, we could detect a rather low TRPV1 expression in VSMCs at the mRNA level (Cp value around 30), after validating the primer pair in NGF-stimulated PC-12 cells. We conclude that rat vascular smooth muscle cells do not possess canonical TRPV1 channel activity, which could explain the observed antiproliferative effect of capsaicin.

Thermodynamic stability of human lipocalin-type prostaglandin D synthase under various pH conditions.

Lipocalin-type prostaglandin D synthase (L-PGDS) binds various hydrophobic small molecules. Since we aim to use human L-PGDS as a carrier in a drug delivery system (DDS) for poorly water-soluble drugs, quality control of the protein is indispensable. In this study, we investigated the thermodynamic stability of human L-PGDS under various pH conditions. Differential scanning calorimetry revealed that the thermal unfolding of L-PGDS was an almost-reversible two-state transition between the native and unfolded states over the pH range from 2.5 to 7.4. The linear relationship of ΔH(Tm) to Tm in this pH range gave a heat capacity change (ΔCp) of 4.76kJ/(K·mol), which was small compared to those commonly found in globular proteins. The temperature-dependent free energy of unfolding, ΔG(T), specified by Tm, ΔH(Tm) and ΔCp, showed a pH dependence with the highest value at pH7.4 closest to the isoelectric point of 8.3. The small value of Cp resulted in a large value of ΔG(T), which contributed to the stability of the protein. Taken together, these results demonstrated that human L-PGDS is sufficiently thermostable for storage and practical use and can be useful as a delivery vehicle of protein-based DDS.

Structural and thermodynamic effects of hydration in Na-zeolite A (LTA) from low-temperature heat capacity

Zeolite A (Linde Type A; LTA) is an industrially important porous mineral that has recently been shown to exhibit framework flexibility upon changes in hydration level. To investigate the flexibility transition from a thermodynamic perspective, we have performed heat capacity measurements on sodium zeolite A at seven incremental hydration levels ranging from zero to equilibrium with ambient air. Excess low-frequency vibrations beyond the predictions of the Debye model are found in all samples, and the frequency of these vibrations increases as a function of hydration level. This suggests that an increase in hydration causes a decrease in at least one type of framework flexibility for sodium zeolite A. In addition, a subtle excess heat capacity contribution from 150 to 280 K is observed only for low and intermediate hydration levels, which may arise from a transformation tied to framework flexibility previously observed in zeolite A via gas absorption calorimetry. Values of the standard thermodynamic functions Cp,m°, Δ0TSm°, Δ0THm°, andΦm° are also reported.

The physicochemical properties of a starch–sodium stearoyl lactylate complex formed via annealing treatment in ethanol solutions

This work examined the physicochemical properties of potato starch–sodium stearoyl lactylate (SSL) complexes formed by annealing potato starch with 0.6% SSL in different ethanol solutions (65–100%). The complexes exhibited a higher iodine binding capacity compared to annealed potato starch without SSL. The iodine binding capacity values of the complexes increased from 46.65% to 96.87% as the ethanol solution concentration decreased from 100% to 65%. Rapid viscosity analysis showed peak viscosities of the complexes ranging from 11 cP to 2012 cP and breakdown values of zero, indicating that the complex pastes showed both thermal and shear stability. Differential scanning calorimetry results showed an increase in the gelatinization temperature of starch treated in SSL–ethanol solutions (65–85%) and a decrease in enthalpy. The formation of complexes markedly decreased the swelling power and solubility of the starch granules. Overall, the starch–SSL complexes formed by annealing in ethanol solution had the performance characteristics of chemically crosslinked starch and have potential applications in high-temperature processed foods. • Annealing starch in ethanol solution with sodium stearoyl lactylate (SSL) was studied. • The disordered structure of amylose induced by SSL and ethanol was formed. • The formation of disordered structure complexes was affected by ethanol concentration. • The thermal stability of starch was enhanced by ethanol annealing treatment with SSL.

The Benefit Using a Circular Flow Disturbance on the Darrieus Turbine Performance

Darrieus is a vertical-axis type turbine with difficulty rotating at low current velocity. Adding a circular flow disturbance in front of the Darrieus turbine can improve the self-start capability. This study has aimed to improve the turbine's performance by identifying the configuration and diameter ratio of flow disturbance. Numerical modelling in transient conditions has been done by using Computational Fluid Dynamics (CFD) software with a sliding mesh technique. There are four diameter ratios ds/D 0.1, 0.3, 0.5, and 0.7 and three variations of cylinder position. Each combination variation has been simulated at current velocity of 0.3, 0.4, 0.5, and 0.6 m/s. As a result, depending on where the cylinder installation is located, the circular flow disturbance has an effect that might hinder or enhance the performance of the turbine. The best result is at the flow disturbance position of -60o with a diameter ratio of ds/D 0.5 at TSR 1.43. The maximum coefficient of power (Cp) value has increased by 38%. Furthermore, at overall current velocities with a range of 0.3–0.6 m/s, the average Cp has increased of 30% with the best diameter ratio usage of ds/D 0.5.

Investigation on the Performance of Micro Wind Turbine Rotor Using Whale-Inspired Blade Based on Low Wind Regime

The potential of wind energy in a country varies depending on the region. For example, in Northern regions of Nigeria, cities like Minna, Sokoto, Kano and Jos are the most potential locations and experience not more than 5.24 m/s mean wind speed with Jos having the highest average wind speed. In most cases internationally wind turbines are design to operate at the rated wind speed much greater than mean wind speeds in Nigeria (in most cases above 8 m/s). Installation of these wind turbines in a similar location to Nigeria (in terms of wind speed condition) will significantly decrease their performance. Therefore, it become necessary to design and produce wind turbines that will function efficiently in low wind speed locations. One of the technologies to improve wind turbine rotor blade effectiveness in low wind regime is to boost the operating angle of the wind turbine, and hence the prospect for the improvement of wind turbine performance. An innovative way recognized previously by some researchers for increasing the working angle of the blade at low wind speed for improved performance is modification of wind turbine blade leading edge. This research studied three-bladed wind turbine rotor with modified blades leading edges (by incorporating sinusoidal bumps) at low wind speeds using CFD method. Two CAD models of wind turbine blades based on 0.8m three-bladed wind turbine rotor were modelled and simulated. One blade model is having straight leading edge (N-Blade) and the other having bumpy leading edge (M-Blade). Both models have NASA LS (1)-0413 cross-section profile. Simulations were run using ANSYS 20 from a velocity of 2 m/s to 10 m/s at the interval of 2m/s considering TSR of 6 and 8. At a TSR of 6, the coefficients of performance (Cp) values are not equal, with the straight blade having better performance than the bumpy blade at all velocities tested; the Cp values of blade with straight leading edge are 0.180, 0.267, 0.300, 0.313, 0.322 at respective velocities of 2, 4, 6, 8, and 10m/s, while Cp values of blade with bumpy leading edge at the same velocities are 0.165, 0.250, 0.281, 0.294, and 0.303 respectively. At a TSR of 8, the CP values closely match for both straight and bumpy blade at all velocities tested for. Simulations were further run at constant angular velocity of 120 rad/s for a TSR of 2, 4, and 10, where the peak performance occurs is around TSR of 6 and 8. For instance, the Cp values of M-Blade are 0.022, 0.173, 0.294, 0.313, and 0.116 respectively at the TSR of 2, 4, 6, 8, and 10. At TSR of 2, 4, 8 and 10, the performance of both airfoils closely matches except at a TSR of 6 where the N-Blade Cp value is 0.313 and is better than that of M-Blade Cp value (0.294). It shows that the blade leading edge modification could not have advantage at all flow conditions and size of the HAWT blades; it shows no advantage on the performance of the rotor blade tested in this research at the velocities at which the simulation was conducted.

Highlighting early detection of thyroid pathology and gestational diabetes effects on oxidative stress that provokes preterm delivery in thyroidology: Does that ring a bell?

ObjectivesAd fontes, the status of the thyroid gland, and metabolic disturbance lead to the alteration of oxygenation. In pregnancy, it is particularly crucial to possess all predictive parameters. MethodsThis cross-sectional study was conducted at the Clinic of Gynecology and Obstetrics, Clinical Center of Serbia, Belgrade, Serbia, between 2017 and 2021 which study included a total of 99 women who had been admitted for preterm delivery and had undergone thyroid analysis, detected Hashimoto thyroiditis, and Oral Glucose Tolerance Test (OGTT) 40 days after delivery and had pathological Homeostatic Model Assessment for Insulin Response (HOMA IR) indices. In the group of urgent patients with preterm delivery, we looked after not only routine Doppler of the umbilical artery, but we measured specific ratios such as the Cerebroplacental ratio (CP). ResultsThe mean maternal age was 32.23 ± 5.96 years and the mean gestational age was detected as 35.40 ± 2.39 weeks. The delivery was completed vaginally in 77 women (78%) and surgically in 22 (22%). The Mean APGAR score was 8.44 ± 1.18, the mean birth weight was 2666.87 ± 622.17g and the cases undergoing cesarean section had significantly higher values of pulsatility index (1.85 ± 0.27 vs. 1.34 ± 0.31) and CP (1.22 ± 0.26 vs. 0.47 ± 0.17). ConclusionsThe introduction of Doppler sonography for blood flow assessment helps to form a complete clinical description of the patient, particularly in conditions where oxidative stress became provocative by the thyroid gland antibodies and gestational diabetes in Thyroidology.

Thermodynamic properties of LiNiO2, LiCoO2, and LiMnO2 using density-functional theory.

The formation energies of LiCoO2, LiNiO2 and LiMnO2 were calculated using a combination of adequately selected Hess cycles and DFT computations. Several exchange-correlation functionals were tested and PBE for solids (PBEsol) turned out to be the most accurate. The enthalpies of formation at 0 K are -168.0 kJ mol at-1 for LiCoO2, -173.2 kJ mol at-1 for LiNiO2, -209.9 kJ mol at-1 for o-LiMnO2 and -208.8 kJ mol at-1 for r-LiMnO2. In comparison to experimental formation energy data, a difference of 1.6 and 0.01 kJ mol at-1 was obtained for LiCoO2 and LiMnO2, respectively. By contrast, a much larger discrepancy, around 24 kJ mol at-1, was obtained for LiNiO2 and confirmed by using an additional and independent Hess cycle. The influence of slight crystallographic distortions associated with magnetism and/or the Jahn-Teller effect on energy was carefully searched for and taken into account, as well as corrections arising from vibrational contributions. Hence, these results should motivate future measurements of the thermodynamic properties of LiNiO2, which are currently scarce. Vibrational contributions to the structural and energetic properties were computed within the harmonic and the quasi-harmonic approximations. The LiCoO2 heat capacity at constant pressure is in excellent agreement with experimental data, with a difference of only 3.3% at 300 K. In the case of LiNiO2 the difference reaches 17% at 300 K, which could also motivate further investigation. The Cp(T) value for the orthorhombic phase o-LiMnO2, for which no previous data were available, was computed. Structural properties such as specific mass, bulk modulus and coefficient of thermal expansion are presented.

A finite element based parametric study to assess the suitability of factors used in EJMA for estimation of the meridional stresses in bellows

Bellows are highly engineered components. In general, the design of bellows is carried out as per the standards of the expansion joints manufacturer’s association (EJMA). In EJMA, the basic form of the expressions for estimation of stresses was derived by considering the half convolution of the bellows as a strip beam. Since axisymmetric shell theory leads to a more realistic response of the bellows, EJMA had introduced factors Cp, Cd and Cf for estimation of the meridional stress in the bellows due to pressure and deflection. These factors in EJMA are plotted as a function of two parameters viz. QW and QDT, which are dependent on bellows geometry and ply thickness. This paper discusses the suitability of the above-mentioned factors considering various configurations of the bellows. A finite element based parametric study was carried out and meridional stresses in the bellows were calculated due to pressure and deflection loading for various values of the QW and QDT. Around 36 bellows geometries with different ranges of QW and QDT were analysed numerically. Based on FE analysis, the EJMA factors Cp, Cd and Cf values were estimated and compared with the corresponding values given in EJMA. It was observed that for both shallow (QW approaching 1) and deeper convolutions (QW approaching 0.2), the EJMA solutions lead to an under prediction of membrane stress due to deflection loading and over-prediction of meridional bending stress due to deflection and pressure loading. The effect of geometric nonlinearities on elastically calculated stresses bellows was quantified for various geometries.

Synthesis and characterization of ammonium-based protic ionic liquids for carbon dioxide absorption.

A series of ammonium-based protic ionic liquids (APILs) namely ethanolammonium pentanoate [ETOHA][C5], ethanolammonium heptanoate [ETOHA][C7], triethanolammonium pentanoate [TRIETOHA][C5], triethanolammonium heptanoate [TRIETOHA][C7], tributylammonium pentanoate [TBA][C5] and tributylammonium heptanoate [TBA][C7] was synthesized via proton transfer. Their structural confirmation and physiochemical properties namely thermal stability, phase transition, density, heat capacity (Cp) and refractive index (RI) have been determined. Specifically, [TRIETOHA] APILs have crystallization peaks ranging from -31.67 to -1.00 °C, owing to their large density values. A comparison study revealed the low Cp values of APILs in comparison to monoethanolamine (MEA) which could be advantageous for APILs to be used in CO2 separation during recyclability processes. Additionally, the performance of APILs toward CO2 absorption was investigated by using a pressure drop technique under a pressure range of 1-20 bar at 298.15 K. It was observed that [TBA][C7] recorded the highest CO2 absorption capacity with the value of 0.74 mole fraction at 20 bar. Additionally, the regeneration of [TBA][C7] for CO2 absorption was studied. Analysis of the measured CO2 absorption data showed marginal reduction in the mole fraction of CO2 absorbed between fresh and recycled [TBA][C7] thus proving the promising potential of APILs as good liquid absorbents for CO2 removal.

Hybrid nanocomposite of vanadium dioxide and carbon nanotubes embedded in a gypsum binder for thermal energy storage

This investigation studied the heat storage capacity of a gypsum blinder with a hybrid nanocomposite (NH) of vanadium dioxide and multiwall carbon nanotubes (VO2/MWCNT). The influence of the NH in the hydration kinetics and hydrated products was determined. The effect of the incorporated amount of NH in the wettability, mass loss by humectation-drying cycles, thermal conductivity, specific heat (Cp) and gypsum thermal performance at 40 °C was determined. Characterization techniques exhibited that the presence of VO2/MWCNT did not modify hydration kinetics and phases development, water drop angle or compressive strength. Nevertheless, gypsum blinders mass loss increased with the presence of the nanocomposite after 6 humectation-drying cycles. According to the thermal properties, it was found that the NH addition increased gypsum blinders thermal conductivity and Cp values. Finally, it was concluded that gypsum with VO2/MWCNT promotes self-thermal regulation properties without affecting its performance. The usage of VO2/MWCNT embedded in a gypsum as a construction material would provide thermal comfort conditions in buildings.

Statistical Analysis using Taguchi Method for Designing a Robust Wind Turbine

The current paper presents the tolerance and parameter design for robust wind turbine. By utilizing the traditional Taguchi method along with its extensions, there is a way of designing a robust wind turbine by considering multiple objectives, constraints and design variables. The concept of design of experiment (DOE) i.e.; Taguchi Method is used to evaluate the constrained and unconstrained problems for the optimization. The current work produces an inexpensive and simpler approach for robust vertical axis wind turbine. DOE (Taguchi Method) of L-9 Orthogonal Array having four parameters along with their three levels i.e; type of NACA aerofoil, Reynolds number, Mach number and Angle of attack are utilized for the optimization and to derive the corresponding optimal values of CL, CD and CP. The parameters like coefficient of lift, drag and power for the wind turbine was determined by Q-Blade software, which is use for designing of wind turbine blades. From the obtained results the inferences drawn were: for CL the major impact was due to Reynolds number and least was due to angle of attack, for CD the major and minor impacting factors were angle of attack and Mach number respectively and for CP the most and least influenced parameters were Reynolds number and Mach number respectively. Also, for obtaining the optimized parameters, the Grey based Taguchi method was utilized which has the combination of orthogonal arrays and grey relational analysis. The analysis showed that the NACA0021 has the maximum lift coefficient of 1.0361 and the minimum drag coefficient of 0.02190 in the case of NACA0021 aerofoil.

Pengaruh Overlap Ratio pada Model Turbin Savonius terhadap Karakteristik Koefisien Daya Berdasarkan Eksperimen Pada Wind Tunnel

Wind energy is a resource that is abundant, environmentally friendly, and renewable, therefore it has the potential to be developed. Savonius vertical axis type is suitable for application in low wind speed conditions. The Savonius wind turbine has good self-starting so that it is able to rotate the rotor even though the wind speed is low, besides that the torque it produces is relatively high. This study aims to determine how differences in OR affect the performance of Savonius turbines with an aspect ratio (AR) of 2. The experimental method was applied in this research to investigate the characteristic Cp of the model using the wind tunnel with different overlap ratios of 0.1, 0.15, 0.2, 0.25, and 0.3. The wind turbine model that has been made using a 3D printing process made of PLA + material. The results obtained in each OR test are the maximum Cp value for the variation OR 0.1, which is 0.121, OR 0.15, the maximum Cp value obtained is 0.213, OR 0.2, the maximum Cp value is 0.245, OR 0.25, the maximum Cp value is 0.224 and OR 0.3, the maximum Cp value is 0.210. Based on the five overlap variations, the maximum Cp ratio is obtained at OR = 0.2, namely Cp = 0.245 and TSR = 0.7. The OR value of 0.2 is able to maximize turbine power and minimize negative torque because the flow through the overlap area can maximally direct wind power to the maximum backward blade.

Effect of Harvesting Time and Phosphate Bio fertilizers on the Nutritive Value of Two Maize Varieties

Two Maize (Zea mays) varieties namely (Hudibia and Mugtama) and two harvesting times were used in this study to evaluate the effect of inorganic phosphorous(P2O5) and phosphate biofertilizers namely, Bacillus, mycorrhiza and the combination of them on maize forage quality. The evaluation was done by determining the percentage of CP, EE, OM, NDF, ADF, ADL, in vitro dry matter digestibility, and in situ degradability. A significant difference (P<0.05) was found between the two varieties for all parameters except for CP. Early time of harvest had the highest value of CP, EE, OM and DMD, and the lowest value of NDF, ADF and ADL. The highest percentage of organic matter (89.45%) was found for the treatment with bacteria alone, while the highest percentage of CP (12.9%) was found for the combination between bacteria and mycorrhiza, while the lowest percentage was found for the control. The highest value of DMD was recorded for the combination between bacteria and mycorrhiza while the lowest value was found for the control. The effect of inorganic phosphorous source (P2O5) and phosphorous biofertilizers on the fiber types was significant (P<0.05). For NDF the lowest value (52.52 %) was recorded in the combination between bacteria and mycorrhiza, while for ADF the combination between inorganic phosphorous and bacteria secured the lowest value (39.98). The highest readily degradable faction (a) was found in the Hudibia variety when fertilized by inorganic phosphorous + mycorrhiza, while the highest slowly degradable fraction (b) was found in the Mugtamaa Varity when fertilized by phosphorous+ bacteria. The highest potential degradability (PD) was found in Mugtamaa variety when fertilized by inorganic phosphorous+ mycorrhiza. From this study, it could be concluded that the combination between bacteria and mycorrhiza improved the nutritive value of the forage by increasing CP and DMD content and decreasing the NDF content.

Biomass and Coal Ash Sintering—Thermodynamic Equilibrium Modeling versus Pressure Drop Test and Mechanical Test

The problem of biomass combustion and co-combustion is a particularly important aspect of many district heating systems, where the use of biomass makes it possible to reduce CO2 emissions. The present article is a continuation of previous studies of the behavior of the mineral matter of selected fuels during the sintering processes. Three biomasses were studied: wheat straw, barley straw and rye straw, as well as two coals from Polish mines: bituminous coal and lignite. The study included ultimate and proximate analyses and oxide analysis. On the basis of the oxide analysis and using FactSage 8.0. software, the sintering process of ash from selected fuels was simulated. In particular, the content of the slag phase as well as the values of the specific heat cp and density were determined without considering the gas phase. The obtained results were compared with the results of measurements of fracture stress (mechanical method) and pressure drop (pressure drop test) determined during the sintering process of the ash samples. The study showed that there is a fairly pronounced correlation between the sintering temperatures determined by the mechanical and pressure drop test and the physical properties of the ashes, such as density and heat capacity, and chemical properties, i.e., the content of the slag phase. The completed research work indicates and confirms that nonstandard methods of studying ash sintering temperatures (mechanical and pressure drop test) are very promising because they directly reflect the behavior of coals and biofuels in combustion systems.

Evaluating energy loss with the entropy production theory: A case study of a micro horizontal axis river ducted turbine

Hydrokineticpoweras acleanrenewableenergy has been aroused awidespread concern. Horizontal axis turbines are widely used in the field of tidal and river current energy power generation, but their internal flow loss characteristics have not been fully revealed. In this paper, a micro horizontal axis river ducted turbine is taken as the research object, and the flow loss characteristics of the turbine under different yaw angles and tip clearances are analyzed by numerical simulation method combined with entropy production theory. A detailed entropy production analysis shows that most of the energy losses take place near the blade tip, at the outlet of the duct, and in the downstream wake region. The turbulent dissipation is the main cause of entropy generation in the ducted turbine. Results demonstrated that with the increase of the yaw angle, the power coefficient Cp increases first, and then reduces. The Cp is up to maximum at θ = 10°. When θ = 25°, the maximum value of Cp decreased by 24.8%, compared with θ = 10°. It is also suggested that there is no obvious negative effect to shaft work and power coefficient for ducted turbine under certain yaw environment (θ ≤ 10°) and the optimal tip clearance should be between 0.02D and 0.04D.

Sustainable microbial fuel cell functionalized with a bio-waste: A feasible route to formaldehyde bioremediation along with bioelectricity generation

Bioelectrochemical systems, especially microbial fuel cell (MFC), are gaining popularity owing to their eco-friendly and energy generation with bioremediation. Due to its unstable electrode material, MFCs have poor electron transportation and production. To increase electron transport and bacterial biocompatibility, better anode materials are needed. Waste palm kernel shell-derived graphene oxide (PKS-GO) and reduced graphene oxide (PKS-rGO) were used to produce the anode electrodes to increase electron transport. The MFC with the PKS-rGO anode generated more energy (24.47 mW/m2) than the PKS-GO anode (13.77 mW/m2). Similarly, the maximum current densities recorded for both anodes were 84.98 mA/m2 for PKS-rGO and 63.74 mA/m2 for PKS-GO. Additionally, the PKS-GO anode showed a 0.00015F/g specific capacitance (Cp) value, whereas the PKS-rGO anode had a Cp value of 0.00021F/g. The enhanced capacitance of the PKS-rGO anode may be due to redox enzymes on microbial cell membranes. The electrochemical impendence spectroscopy also showed a rapid transportation rate of electrons in the case of the PKS-rGO anode. PKS-GO's anode has 1240 ῼ internal resistance, whereas PKS-rGO has 232 ῼ. The secondary use of MFC in wastewater treatment was also taken into account. The PKS-rGO anode (87 %) is more effective in bioremediating formaldehyde (FA) than the PKS-GO anode (81.70 %). The sequence reveals a prominent species of Niallia circulans strain for the PKS-GO anode, and two dominant species for the PKS-rGO anode, Bacillus siamensis strain and Bacillus velezensis strain. A comparative overview shows the effectiveness of the material compared to previous studies. Critical challenges constraining progress in MFC power output enhancement and future perspectives are also included.