The Stirling engine's efficiency is noticeably improved by the addition of a NiTiNOL spring to the base plate, as shown in the experimental results, showcasing the shape memory alloy's impact on the performance output of the Stirling engine. The engine, having undergone modifications, has been officially named the STIRNOL ENGINE. Scrutinizing Stirling and Stirnol engines comparatively, a minuscule improvement in efficiency is evident, yet this advancement opens avenues for future researchers to delve into this new area. Innovative engine designs are anticipated in the future, with a focus on complex configurations and improved combinations of Stirling and NiTiNOL technologies. Investigating performance variations in the Stirnol engine, this research centers around changing the base plate's material and incorporating a NiTiNOL spring element. The experiments necessitate the application of a minimum of four categories of materials.
Geopolymer composites are currently attracting considerable attention as an eco-friendly option for repairing the exteriors of both historical and modern buildings. Even though the application of these compounds is substantially lower than standard concrete, utilizing ecological geopolymer substitutes for their core components offers the potential to significantly diminish the carbon footprint and reduce the emission of greenhouse gases into the surrounding air. The research project sought to develop geopolymer concrete with improved physical, mechanical, and adhesive characteristics, tailored for building facade finishing restoration. Chemical analysis, scanning electron microscopy, and regulatory methods were all incorporated into the experimental procedure. The optimal additive proportions of ceramic waste powder (PCW) and polyvinyl acetate (PVA) were found to produce geopolymer concretes with superior qualities. In these formulations, 20% PCW was incorporated instead of part of the metakaolin, accompanied by 6% PVA. Strength and physical characteristics are maximally enhanced when PCW and PVA additives are combined and administered in optimal dosages. The geopolymer concrete displayed substantial enhancements in compressive strength, increasing by up to 18%, and bending strength, improving by up to 17%. Moreover, water absorption decreased by up to 54% and adhesion increased by up to 9%. A concrete base presents a slightly improved adhesion characteristic for the modified geopolymer composite, when compared to a ceramic base, with a maximum enhancement of 5%. Geopolymer concretes, reinforced with PCW and PVA, display a denser matrix with significantly reduced pore formation and micro-crack generation. Developed compositions are usable in the restoration process of building and structure facades.
A critical analysis of reactive sputtering modeling is undertaken in this work, exploring its evolution over the past fifty years. A comprehensive review of the key attributes exhibited in various experimental studies of simple metal compound film depositions, including nitrides, oxides, oxynitrides, carbides, and others, is provided. The above features are defined by considerable non-linearity and hysteresis. In the initial years of the 1970s, certain chemisorption models were proposed. The models' foundation rested on the expectation of a compound film forming on the target as a result of chemisorption. Their development directly led to the general isothermal chemisorption model, a model which was subsequently modified to include processes occurring on the surfaces of the vacuum chamber and the substrate. Fetuin datasheet Various problems relating to reactive sputtering have necessitated numerous changes to the model. In the subsequent stage of model refinement, the reactive sputtering deposition (RSD) model was proposed, which was predicated on the implantation of reactive gas molecules into the target, involving bulk chemical reactions, chemisorption mechanisms, and the knock-on effect. A different modeling pathway is the nonisothermal physicochemical model, which utilizes the Langmuir isotherm in conjunction with the law of mass action. By employing diverse modifications, this model provided a more comprehensive description of reactive sputtering processes, encompassing situations where the sputtering apparatus featured a hot target or a sandwich target arrangement.
Predicting the depth of corrosion in a district heating pipeline necessitates examining a range of corrosion-related factors. Corrosion depth was evaluated in relation to corrosion factors (pH, dissolved oxygen, and operating time) in this study, which utilized the Box-Behnken method within the context of response surface methodology. To increase the rate of corrosion, galvanostatic tests were executed in a synthetic district heating water solution. EMB endomyocardial biopsy The following step was to perform a multiple regression analysis, utilizing the measured corrosion depth as a basis for determining a formula relating corrosion depth to the contributing corrosion factors. The regression model produced the following formula to calculate corrosion depth (in meters): corrosion depth (m) = -133 + 171 pH + 0.000072 DO + 1252 Time – 795 pH × Time + 0.0002921 DO × Time.
A thermo-hydrodynamic lubrication model is developed to characterize the leakage of an upstream pumping face seal featuring inclined ellipse dimples in a high-temperature and high-speed liquid lubricating regime. The novelty of this model is in its comprehensive approach to the thermo-viscosity and cavitation effects. Numerical calculations explored the effects of operational parameters, including rotational speed, seal clearance, seal pressure, and ambient temperature, and structural parameters, such as dimple depth, inclination angle, slender ratio, and dimple count, on the opening force and leakage rate. The results confirm a relationship between the thermo-viscosity effect and a substantial drop in cavitation intensity, leading to a more potent upstream pumping effect from the ellipse dimples. Importantly, the thermo-viscosity effect likely increases both the rate of upstream pumping leakage and the opening force by approximately 10%. Inclined ellipse dimples are a source of noticeable upstream pumping and hydrodynamic effects. The logically crafted dimple parameter design facilitates zero leakage in the sealed medium, and this simultaneously leads to an improvement in opening force exceeding 50%. Future upstream liquid face seal designs may be guided and theoretically grounded by the proposed model.
This research project aimed to develop a mortar composite that exhibits enhanced gamma-ray shielding, utilizing WO3 and Bi2O3 nanoparticles, and integrating granite residue as a partial replacement for sand. pediatric hematology oncology fellowship An analysis of the physical properties and effects of sand substitution and nanoparticle addition on mortar composites was undertaken. The TEM analysis indicated that Bi2O3 nanoparticles' dimensions were 40.5 nanometers, and WO3 nanoparticles' dimensions were 35.2 nanometers, respectively. Microscopic examination (SEM) showed that increasing the granite residue and nanoparticle content improved the even distribution of the components and minimized the occurrence of empty spaces. Thermal gravimetric analysis (TGA) showed that the material's thermal properties were enhanced by the addition of nanoparticles, without any corresponding reduction in weight at elevated temperatures. Measurements of linear attenuation coefficients (LAC) demonstrated a 247-fold increase at 0.006 MeV in the presence of Bi2O3 and a 112-fold increase at 0.662 MeV. From LAC data, Bi2O3 nanoparticle addition produces a substantial alteration in LAC at low energies, and a slight, yet noticeable, influence at higher energy levels. Gamma-ray shielding properties of mortars were enhanced by the addition of Bi2O3 nanoparticles, which resulted in a decrease in the half-value layer. The observed mean free path of the mortars exhibited a trend of increment with escalating photon energy; nevertheless, the addition of Bi2O3 led to a decreased mean free path and augmented attenuation, ultimately making the CGN-20 mortar the superior choice in shielding capabilities compared to the other mortars. The enhanced gamma ray shielding capabilities of our developed mortar composite hold substantial promise for radiation protection and granite waste recycling.
The practical application of a novel, environmentally sound electrochemical sensor, constructed with spherical glassy carbon microparticles and multi-walled carbon nanotubes in low-dimensional structures, is explored. To determine Cd(II), the anodic stripping voltammetric method was applied to a sensor modified with a bismuth film. The sensitivity of the method was meticulously studied by varying instrumental and chemical parameters. The most suitable values for these parameters were chosen (acetate buffer solution pH 3.01; 0.015 mmol L⁻¹ Bi(III); activation potential/time -2 V/3 s; accumulation potential/time -0.9 V/50 s). The method, operating under the specified conditions, displayed a linear response in the concentration range of Cd(II) from 2 x 10^-9 to 2 x 10^-7 mol L^-1, with a corresponding detection limit of 6.2 x 10^-10 mol L^-1 Cd(II). The sensor's application for Cd(II) detection, as evidenced by the results, exhibited no substantial interference from a variety of foreign ions. Through addition and recovery tests conducted on TM-255 Environmental Matrix Reference Material, SPS-WW1 Waste Water Certified Reference Material, and river water samples, the applicability of this procedure was determined.
During the early development of an experimental pavement, the incorporation of steel slag as a substitute for basalt coarse aggregate in Stone Mastic Asphalt-13 (SMA-13) gradings is investigated, together with an evaluation of the mix's performance and the application of 3D scanning techniques to analyze the pavement's initial textural characteristics. Laboratory testing involving water immersion Marshall tests, freeze-thaw splitting tests, and rutting tests was undertaken to establish the gradation of two asphalt mixtures and assess their strength, resistance to chipping, and cracking. To contrast these laboratory results, the surface texture of the pavement was analyzed to gather data on height parameters (Sp, Sv, Sz, Sq, Ssk), and morphological parameters (Spc), with the objective of evaluating the skid resistance of the mixtures.