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Effects of Ni Loadings on the Structure and Morphology of Carbon Nanotubes Using Nickel Doped Iron Oxide Catalysts

AbstractIron oxide and their different doped iron oxide catalyst have been used for decades and are considered as efficient catalysts in several synthesis schemes including synthesis of carbon nanotubes. The iron oxide of the catalyst is abundant in nature, high catalytic activity at low over potentials, stability in basic media and low cost, making it environmentally and economically attractive. Nickel doped iron oxide catalyst have not been reported in the literature. Doping of nickel over iron oxide catalyst, different percentage 1 %, 5 %, 10 % and 20 % were done by impregnation method. The samples were characterized by X‐Ray powder Diffraction (XRD), Fourier‐Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Energy Dispersive X‐ray (EDX) and Thermo Gravimetric Analysis (TGA). Nickel doped iron oxide was used as catalyst for the synthesis of carbon nanotubes (CNTs) and doping changed the morphology of carbon nanotube (CNTs). FTIR results confirmed the doping and presence of different functional groups. Chemical vapor deposition (CVD) was carried out for the synthesis of multiwall carbon nanotubes (MWCNTs) on nickel doped iron oxide catalyst for different percentage (1 %, 5 %, 10 % and 20 %) separately. CVD assembly was carried in tube furnace and the reaction was checked at two different temperature i.e 700 °C and 750 °C and using methane and compressed natural gas (CNG) as precursors. The catalyst was activated in the furnace at 800 °C for an hour. Methane and argon were used in proportion 2 : 1 inside the furnace. SEM showed formation of CNTs at 750 °C with CNG precursor. Formation of CNTs increased with increasing doping with this CNTs was confirmed by SEM.

Cyclic loading effects on the heat-generation performance of carbon nanotube-embedded cement composites

Abstract This study investigates the heat-generation stability of carbon nanotube (CNT)/cement composites after exposing to cyclic loading conditions. The specimens were fabricated with varying CNT contents and levels of fly ash replacement. Results showed that increasing CNT content reduced electrical resistivity, while the impact on the electrical characteristics was found to be insubstantial, even though a considerable portion of fly ash was replaced. In addition, the electrical resistivity of the specimens after exposed to cyclic loading increased. Electrical heating tests revealed both negative and positive temperature coefficient effects depending on the applied voltages. Higher CNT contents improved the heat-generation capability, but the heating capability decreased after exposed to the cyclic loadings which is deduced from the damage of CNT networks during cyclic loadings. In this regard, the authors concluded that the heat-generation stability can be significantly affected by the applied loadings. Thus, the future research will be conducted to improve the heat-generation stability of the cement-based electrical heating systems as exposed to artificial deteriorations.

Optimization study and application of box-behnken model for probing eggshell supported transition metals based catalysts to synthesize hydrazone & dihydropyrimidinones

Solid supported catalysts have several synthetic applications. Herein, finely ground eggshells were used as a solid support for the preparation of transition metal (Ni, Zn, Cu, Sn and Co) based catalysts to synthesize 2,4-dinitrophenylhydrazone (3) and dihydropyrimidinones (7 and 8). The effect of catalyst load, time and temperature on product yield was studied. Box Behnken Model was employed, and three predictors named catalyst amount (A), reaction time (B), and reaction temperature (C) were used to find the correlation of the predictors with the yield. Second order polynomial equation was used to estimate the effects of these factors. According to the statistical model, about 12% increase in yield was observed as a result of one-unit increase in reaction time while all other terms were kept constant. The values of S (18.1616) and R2 (71.2%) indicate that the statistical model gave an adequate fit to data. Quadratic model for the response surface was used for the analysis of variance (ANOVA) results, the larger F-values, and smaller p-values indicated that the predictors are in good agreement. The linear model terms of predictors were found to be significantly effective for yield (P < 0.05). The response surface and contour plots were also in agreement with the predicted model.

Study on the vibration characteristics of angular contact ball bearing cage under rolling-sliding compound motion

Abstract Cage fracture has become the main form of bearing failure, the study of factors affecting the operating condition of the cage has an important impact on the operating performance and life of bearings. This study takes the angular contact ball bearing H7006C as the object of study and extracts the bearing inner ring and cage speed to analyze the bearing slip rate law. Extract cage vibration data and analyze cage vibration frequency characteristics using the VMD method. The effects of load and speed induced bearing slippage on the vibration characteristics of cages are investigated by varying the induced bearing slippage factors. The effects of load and speed induced bearing slip on the vibration characteristics of cages are investigated separately by varying the induced bearing slip factors. The study found that, at a fixed rotational speed, the bearing slip rate decreases as the axial load increases from 0 to 350N, and then stabilizes beyond 350N. Under fixed load conditions, the bearing slip rate increases with the rotational speed ranging from 1000 to 9000rpm. At a constant speed, the axial load is varied within 50 to 100N, resulting in vibration frequency increases of 72Hz, 43.5Hz, and 24Hz at 1000 rpm, 5000 rpm, and 9000 rpm, respectively. The characteristic frequency of cage vibration rises with increasing load, contributing to smoother cage operation. Nonetheless, as the rotational speed increases, the influence of axial load-induced slippage on the vibration characteristics of the cage diminishes gradually. At a set load of 500N, the amplitudes of the cage vibration eigenfrequencies at 1000rpm, 3000rpm, and 7000rpm are 0.0317, 0.0288, and 0.0174, respectively, decreasing with rotational speed. This indicates that the cage does not operate smoothly. The findings of this study serve as a theoretical foundation for detecting and diagnosing bearing slip and vibration issues in rotating machinery.

General ventilation filters: what acoustic characteristics?

In the field of general ventilation, air filters are widely used, and introduced in ventilation ductworks, or air-handling units. These filters are passed through by air flow and noise. However, their characteristics of sound attenuation and sound generation are very poorly known, used and tested. This presentation reports a study done in collaboration with French air filtering manufacturers members of CETIAT. More than thirteen 592x592 mm filters representing four different types of air filters commercially available have been tested in laboratory, to characterise the insertion loss and the noise generation. Those types of filters are mini pleated (50 &amp; 100 mm thickness), V-bank, bags and pleated, with different materials such as glass fiber and synthetic fiber. In addition, the effect of the dust loading has been investigated the sound characteristics as well as the influence of a series installation of a prefilter and a filter. These experimental data will be helpful for acoustic studies of ventilation networks. Some results about sound absorption can be related to the characteristics of the filters, thickness or shape but also to the loading and the use in series, whereas no obvious relation can be found for sound generation.

Mechanical Loading Modulates AMPK and mTOR Signaling in Muscle Cells.

Skeletal muscle adaptation to exercise involves various phenotypic changes that enhance the metabolic and contractile functions. One key regulator of these adaptive responses is the activation of AMPK, which is influenced by exercise intensity. However, the mechanistic understanding of AMPK activation during exercise remains incomplete. In this study, we utilized an in vitro model to investigate the effects of mechanical loading on AMPK activation and its interaction with the mTOR signaling pathway. Proteomic analysis of muscle cells subjected to static loading (SL) revealed distinct quantitative protein alterations associated with RNA metabolism, with 10% SL inducing the most pronounced response compared to lower intensities of 5% and 2% as well as the control. Additionally, 10% SL suppressed RNA and protein synthesis while activating AMPK and inhibiting the mTOR pathway. We also found that SRSF2, necessary for pre-mRNA splicing, is regulated by AMPK and mTOR signaling, which, in turn, is regulated in an intensity-dependent manner by SL with the highest expression in 2% SL. Further examination showed that the ADP/ATP ratio was increased after 10% SL compared to the control and that SL induced changes in mitochondrial biogenesis. Furthermore, Seahorse assay results indicate that 10% SL enhances mitochondrial respiration. These findings provide novel insights into the cellular responses to mechanical loading and shed light on the intricate AMPK-mTOR regulatory network in muscle cells.

Boosting the bifunctional catalytic activity of Co3O4 on silver and nickel substrates for the alkaline oxygen evolution and reduction reactions

Developing an efficient bifunctional catalyst for oxygen reduction (ORR) and evolution reactions (OER) is a crucial step for the wide commercialization of alkaline water electrolyzers. However, a proper assessment and comparison of various catalysts is still challenging due to the different catalyst substrates and loadings. In this work, Co3O4 spinel nanoparticles (NPs) were investigated as a bifunctional catalyst at different substrates of glassy carbon or Ag bulk substrate or Ni particles and with different loadings. For Co3O4 (800 µg cm-2)/Ag electrode, not only the overpotential for ORR was 50 mV lower than the bare Ag electrode, but also the OER overpotential was 40 mV lower than the sole Co3O4. Besides, less than 1% peroxide intermediate was detected during ORR using the rotating ring disc electrode (RRDE) method, suggesting a 4-electron O2 reduction. Tafel slopes of 70 and 60 mV dec‑1 at Co3O4/Ag were obtained for ORR and OER, respectively. The improved bifunctional activity could be attributed to a synergistic effect between Co3O4 and the Ag support. For the loading effect, it is revealed that the number of accessible sites of Ag surface decreases with increasing the Co3O4 loading, as evaluated from lead-underpotential deposition measurements. Interestingly, after running ORR/OER cycles, the surface area increased by 4–6 times. This surface roughening was also confirmed by SEM and EDX. The study was extended to Co3O4+Ni mixed catalyst to validate the effect of the support on this induced synergism. Hence, this work provides a simple route for designing potential effective catalytic interfaces and contributes to unravelling the influence of the substrate and loading on the catalyst activity for water electrolyzers.

Drowning in emails: investigating email classes and work stressors as antecedents of high email load and implications for well-being.

High email load has been associated with impaired well-being because emails impose specific demands, disturb the workflow, and thereby overtax individuals' action regulation toward prioritized goals. However, the causes and well-being-related consequences of email load are not yet well understood, as previous studies have neglected the interaction type and function of emails as well as co-occurring stressors as antecedents of high email load and have relied predominantly on cross-sectional designs. In two studies, we aimed to clarify the nature of email load through the lens of action regulation theory. The first study, a two-wave investigation with a fortnightly interval, examined the lagged relationships among email load, work stressors, strain, and affective well-being. The sample included 444 individuals across various occupations and organizations, with 196 of them working from home or remotely at least part of the time. In the second cross-sectional study, we surveyed 257 individuals using a convenience sampling approach, 108 of whom worked from home or remotely at least partially. This study focused on evaluating how different email classes-distinguished by email interaction type (received vs. processed) and email function (communication vs. task)-serve as predictors of high email load. In Study 1, we found a positive lagged effect of high email load on strain, even when controlling for the co-occurring stressors time pressure and work interruptions. In addition, lagged effects of email load on time pressure and interruptions were identified, while no evidence was found for the reverse direction. The results of Study 2 suggest that only the number of communication-related emails received, but not the number of task-related emails received, or the number of all emails processed contribute to high email load. Findings suggest that email load can be considered a unique stressor and that different classes of email need to be distinguished to understand its nature. Clarifying the sources of email load can help develop effective strategies to address it.

Dynamic response and vibration suitability analysis of the large-span double-connected structure under coupled wind and pedestrian loads

Modern buildings increasingly utilize lightweight, high-strength materials and feature high-rise, large-span structural designs. These structures often exhibit low natural frequencies and are susceptible to resonance from low-frequency dynamic loads such as wind and pedestrian loads. This paper focuses on a large-span double-connected structure and analyzes its dynamic response under the combined effects of wind and pedestrian loads. First, a finite element model of the structure was created using ANSYS, and model validity verification and modal analysis were performed. Second, a Fourier-based pedestrian model was used to simulate pedestrian loads and generate time-range data. The pulsating wind speed was generated from the Davenport spectrum using the harmonic superposition method. Wind load time-range data were calculated for different heights using Bernoulli’s theorem. Finally, the solution yields information about the dynamic response of the structure. The study revealed maximum vertical comfort ratings in the connecting corridor were achieved when crowd density did not exceed 0.3 persons/m2. The connecting corridor’s most unfavorable horizontal comfort level was evaluated as a medium, except for the 0-degree wind angle condition. This paper provides experience in studying the dynamic response and vibration suitability assessment of the large-span double-connected structure under wind and pedestrian loads.

Evaluating Heat Stress Effects on Growth in Tunisian Local Kids: Enhancing Breeding Strategies for Arid Environments.

This study evaluates the impact of thermal load on the weights of Tunisian local kids using 24 models with cubic and quadratic Legendre polynomials, based on daily temperatures (Tmin, Tmax, and Tavg) on the day of weight recording and averaged over 7, 14, and 21 days before weighing. The deviance information criterion (DIC) consistently shows that cubic polynomial models offer a better fit than quadratic models, highlighting their superior accuracy in studying the effects of thermal load on kid weights. The models with the best fit utilized average or maximum temperatures over 14 or 21 days. The patterns of response were similar across the temperature variables and periods, showing a stable weight response at lower temperatures (thermoneutral region) followed by a decline as the temperatures increased. The weight loss was -125 g/°C beyond the moderate heat stress threshold (Tavg21 = 17.7 °C) and -450 g/°C beyond the severe heat stress threshold (Tavg21 = 25.3 °C) for Tavg21. The heat stress thresholds for moderate heat stress (HS1) were 8.6 °C for Tmin14, 27.4 °C for Tmax14, and 18.6 °C for Tavg14; moreover, for acute heat stress (HS2), they were 17.2 °C for Tmin14, 32.4 °C for Tmax14, and 25.5 °C for Tavg14. High variability in individual responses was observed, with differences in the slope of response ranging from 2.0 kg/°C for moderate heat stress to around 3.0 kg/°C for severe heat stress for Tavg. The correlations between the weights under different temperatures were low, indicating that rankings based on weight could change with varying heat conditions. The animals with larger weight levels generally demonstrated better heat tolerance, and those with good heat tolerance under moderate conditions were also likely to have good tolerance under severe conditions.

Reliability analysis and calibration for flexural design provisions of GFRP-RC beams

This study aims to conduct reliability assessment and calibration of the design provisions for flexural capacity in existing design codes for glass fiber reinforced polymer bar reinforced concrete (GFRP-RC) beams. Firstly, model uncertainties for three design codes including GB 50608-2020, ACI 440.1R-15 and CSA S806-12 were evaluated using the statistical analysis methods. Subsequently, the reliability analysis of flexural capacity in three design codes was investigated based on Monte Carlo Simulation (MCS) method, considering stochastic factors such as material properties, geometric parameters, model uncertainties and load effect combinations. Moreover, the influences of tensile strength of GFRP bar, the ratio of reinforcement ratio to balanced reinforcement ratio (ρf/ρfb) and the live-to-dead load effect ratio (θ) on reliability index were explored. Meanwhile, the calibration of GFRP material partial factor (γf) for GB code was performed with the target reliability index of 3.7, based on the least squares analysis. Finally, the flexural capacity provisions of GFRP-RC beams in the GB code was revised for improving the reliability index under a relatively low live-to-dead load effect ratio θ by re-calibrating parameter γf for GFRP bar tensile failure and introducing revision coefficient ξ for concrete compressive failure, achieving target reliability index over 3.7.

Visible Light-Triggered Catalytic Performance of Reduced Graphene Oxide Decorated With Copper Oxide Nanocomposite for Degradation of Rhodamine B Dye and Kinetics Studies.

Herein, novel nanocomposites based on reduced graphene oxide decorated copper oxide nanoparticles (rGO/CuO) were prepared by the in situ co-precipitation method. The structural, morphological, and optical characterization of as-prepared nanocomposites was performed by powdered x-ray diffraction (p-XRD), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR), Raman, and ultraviolet-visible (UV-Vis) spectroscopy, respectively. The as-prepared nanocomposites exhibited better photocatalytic activity of rhodamine B dye with maximum ~94% degradation in 120 min with a rate constant of 0.2353 min-1 under optimized conditions. Furthermore, the effects of solution pH and catalyst loading are studied on the degradation process. Therefore, this state-of-the-art strategy for the decoration of CuO nanoparticles onto the surface of rGO nanosheets could be an ideal platform for fabricating highly efficient photocatalysts.

Coupled Modeling of Sea Surface Launch Flow and Multi-Body Motion

To simulate the launching process of missile complex flow, movement, and constraint states, a multifield coupling model is put forward based on a computational fluid dynamics (CFD) method. In this coupled model, a CFD method is used to solve the three-dimensional compressible transient flow, and the six-degree motion of the launching platform is considered, and the virtual contact method is used to deal with the constraint states of the guideway and the slider. The active force and moment are applied to the launching platform to simulate its rolling, pitching, and heaving motions under the 5-level waves. Collision detection is carried out through the minimum clearance distance between the slider and the guideway, and the contact force is handled by a modified Herz collision model. In the problem of launching a missile from the water surface, the change characteristics of the flow field, the load response characteristics, and the relative motion laws of the missile and the launching platform during the catapulting process are investigated. The results show that the motion laws of the projectile and the launch tube in the constrained direction are the same, and the established coupling model is able to simulate the launch separation process of the missile in the constrained state. In addition, the effect of wind load on the missile ejection process is analyzed using the coupled model.

Electrophysiological and hemodynamic mechanisms underlying load modulations in visuospatial working memory: A functional near-infrared spectroscopy (fNIRS) and electroencephalogram (EEG) study.

The n-back task has been widely used to study working memory. Previous studies investigating the electrophysiological (electroencephalogram [EEG]) and hemodynamic correlates (functional near-infrared spectroscopy [fNIRS]) of the n-back task have been generally based on verbal stimuli and only investigated EEG frequency bands. We simultaneously acquired the EEG and fNIRS in 35 participants (16 males; age = 26.4 ± 4.3 years; educational attainment = 18 ± 2 years) during a visuospatial n-back task. The task encompassed a control condition and a low (requiring to recall one previous stimulus) and a high (requiring to recall two previous stimuli) working memory load experimental conditions. Accuracy decreased and reaction times slowed in the high compared to both low load and control conditions. Regarding EEG, P3a showed higher amplitude in the experimental conditions compared to the control one, and P3b exhibited higher amplitude in the low compared to the high load condition. Regarding fNIRS, the high load condition showed higher deoxygenated hemoglobin compared to the control one. Moreover, the central frontopolar cortex showed higher activation compared with the left frontal cortex. Our study showed that working memory load during a visuospatial n-back task influenced behavioral and electrophysiological indices. Even if the load effect was only observed for deoxygenated hemoglobin on hemodynamic data, this was in line with previous studies and coherent with its electrophysiological correlates. Thus, our study confirms that EEG and fNIRS can be successfully used in multimodal acquisitions, but also highlights that future studies are needed to develop a novel version of the task. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Characteristic analysis of rain-wind induced stay-cable vibration based on friction damper in field observation

Abstract Both domestic and foreign scholars have developed various friction dampers with good characteristics. The primary types of friction dampers include conventional friction dampers, Pall friction dampers, Sumitomo friction dampers, and Centripetal friction dampers. The components of these dampers will slip or deform under load effect when the energy is consumed by friction. As the structural vibration period increases while the external energy input decreases, the vibration amplitude is reduced. This vibration reduction method is widely used in the automotive industry. Most of the hysteresis models of dampers are similar to rectangular shapes, making the selection of an accurate initial sliding force crucial for the rectangular hysteresis model. Based on the effective data collected from the field observation test, a self-made friction damper, which has a good vibration reduction effect, was used to observe rain-wind induced stay-cable vibration at Dongting Lake Bridge in Yueyang, Hunan Province. Accordingly, some suggestions are put forward for the research work on rain-wind-induced vibration.

Constraining the origin of the Norwegian strandflat – The influence of isostatic and dynamic surface changes

The Norwegian strandflat is a prominent low-relief bedrock surface found near sea level along most of the west coast of Norway. Its origin has been discussed throughout the last 130 years but is yet to be resolved. Some studies suggest that the strandflat represent a tropical weathering front of Mesozoic age that has since been buried and re-exhumed, while others relate its origin to Pleistocene periglacial and glacial processes and/or wave-induced weathering and erosion. Previous interpretations of the strandflat have considered postglacial isostatic uplift, but the impacts of isostatic changes due to glacial erosion and deposition, as well as dynamic surface changes driven by mantle convection, have been largely overlooked. Here we examine how geomorphological-driven isostatic changes and dynamic surface changes have influenced the land-surface elevation along the Norwegian coast during late Pliocene-Quaternary (the last ca. 3 million years). We employ quantitative estimates of glacial erosion and deposition to assess the flexural isostatic response from the resulting load changes. Our analyses show that patterns of geomorphic isostatic adjustments and dynamic surface changes are generally not reflected in the present elevation of the strandflat. Only the loading effect from the deposition of the North Sea Fan can clearly be correlated with the submerged strandflat found near Stad (~62 °N). Our results imply that if the strandflat formed synchronously along the Norwegian coast as a flat surface at sea level, the strandflat we observe today must have developed after the majority of late Pliocene-Quaternary glacial erosion took place, but prior to the main deposition of the North Sea Fan. This would place strandflat formation within the last few glacial cycles, but before the Last Glacial Maximum (LGM). This inferred pre-LGM age of the strandflat is generally consistent with cosmogenic nuclide exposure ages and observed striations on the strandflat. Finally, we examine ice cover and land-surface changes relative to sea level during the last 80,000 years and find no extended periods favorable for synchronous strandflat formation across all regions along the Norwegian coast. This implies that either the strandflat is diachronous, or that the processes of formation have either been extremely fast under certain conditions or are independent of sea level, for instance related to glacial erosion.

Effect of Flexural Fatigue Loading on Mechanical Properties, Permeability, and Rainstorm Resistance of Novel Pervious Concrete

Effect of Flexural Fatigue Loading on Mechanical Properties, Permeability, and Rainstorm Resistance of Novel Pervious Concrete

Full-scale in-situ tests on a displacement cast in situ energy pile: Effects of cyclic thermal loads under different mechanical load levels on pile stress and strain

Numerous full-scale in situ tests have been conducted to assess the effect of thermal cycles on the pile response. However, those studies investigated the response of only precast and cast in-situ energy piles, with limited focus on the impact of the applied mechanical load on the pile response. This study presents the results of a field test conducted on a new type of energy pile, i.e. a displacement cast in-situ energy pile in multilayered soft soils, subjected to different fixed mechanical loads while undergoing simultaneous thermal cycles. Four tests were carried out, each corresponding to various axial loads ranging from 0 to 60% of the pile’s estimated bearing capacity. After applying the axial load on the pile head (0%, 30%, 40%, or 60% of the bearing capacity), the pile was subjected to up to ten thermal cycles. The highest magnitudes of thermal axial strains were observed near the pile top due to the lowest restraint provided by the made ground layer in all tests. Under zero (0%) mechanical load, the thermal axial strains near the pile head were elastic and recoverable, while residual strain was observed near the toe. Under reasonable working mechanical loads (30%, 40%, or 60%) residual strains were observed near both the pile head and the toe, with higher residual strains observed under higher mechanical loads. The results indicate that the cyclic thermal loadings could induce an increase in the compressive stress in the energy pile, attributed to the drag-down effects of the surrounding soil. The compressive stress induced by drag-down effects counteracts thermally induced tensile stress and thus leads to an insignificant effect on the energy pile during cooling. A limited impact of the shaft capacity was observed and was mainly attributed to the drag-down of the surrounding soil and thermal creep along the pile-soil interface.

Soybean oil-based green diesel production via catalytic deoxygenation (CDO) technology using low-cost modified dolomite and commercial zeolite-based catalyst

Green diesel derived from sustainable biomass is an alternative and potential energy source to petroleum fossil fuel replacement in response to reducing carbon footprint and achieving a circular economy, which has sparked public interest and concern in advancing renewable energy development. Catalytic deoxygenation (CDO) is a promising method because it can process a wide variety of feedstocks and produce a diverse range of fuels. The CDO of soybean oil (SO) was executed using a modified low-cost dolomite catalyst denoted as NiO-CD catalyst and its performance has been compared with commercial zeolite heterogeneous-based catalysts such as ZSM-5, HY-zeolite and FCC. The NiO-CD catalyst exhibited exceptional deoxygenation ability, attaining an 88.6 % removal efficiency of oxygenated compounds, markedly surpassing all commercially available zeolite catalysts. The highest degree of CDO of SO via decarboxylation/decarbonylation (deCOx) reaction was achieved due to improvement in particle size, mesoporous structure and the presence of the synergistic effect of modified bi-functional acid-base properties of NiO-CaO/MgO catalyst. To investigate the effect of NiO-CD catalyst loading ranging from 1 to 7 wt%, a One Factor At a Time (OFAT) optimisation study was performed. The current study found that an optimised NiO-CD catalyst loading of 5 wt% yielded the highest green diesel (50.5 wt%) with an 88.63 % hydrocarbon composition. The influence of catalyst loading on deoxygenation activity is significant in green diesel production using NiO-CD catalyst.

Nonlinear Finite Element Formulation for Thin-Walled Conical Shells

This study presents a novel finite element formulation to predict the geometrically nonlinear response of conical shells under a wide range of practical loading conditions. The formulation expresses the discretized equilibrium equations in terms of the first Piola-Kirchhoff stress tensor and its conjugate gradient of the virtual displacements, is based on the kinematics of Love-Kirchhoff thin shell theory and the Saint-Venant-Kirchhoff constitutive model, and captures the follower effect of pressure loading. The formulation takes advantage of the axisymmetric nature of the shell geometries by adopting a Fourier series to characterize the displacement distributions along the circumferential direction while using Hermitian interpolation along the meridional direction. Comparisons with general shell models show the accuracy of the formulation under various loading conditions with a minimal number of degrees of freedom, resulting in a significant computational efficiency compared to conventional general-purpose shell solutions.