Small Values Research Articles

Study on the Hydrodynamics of a Cownose Ray’s Flapping Pectoral Fin Model near the Ground

Cownose rays typically swim close to the ocean floor, and the nearby substrate inevitably influences their swimming performance. In this research, we numerically investigate the propulsive capability of cownose rays swimming near the ground by resolving three-dimensional viscous unsteady Navier–Stokes equations. The ground effect generally has a favorable impact on swimming. The thrust and lift increase as the near-substrate distance decreases. Nevertheless, a body length is the recommended distance from the ground, at which the flapping efficiency and swimming stability obtain a good trade-off. The increase in lift is due to the pressure difference between the dorsal and ventral surfaces of the ray, and the thrust boost is due to the enhanced shear vortex at the fin’s leading edge when swimming near the substrate. Our results indicate that the ground effect is more noticeable when the fin flaps are symmetrical compared to asymmetrical. In asymmetric flapping, the hydrodynamic performance improves at a smaller value than the half-amplitude ratio (HAR). The frequency of flapping also significantly affects swimming performance. We find that a superior flapping frequency, at which maximum efficiency is reached, occurs when flapping close to the substrate, and this superior frequency is consistent with the behavior of our model’s biological counterpart.

Differences in Uniquely Identified Peptides Between ddaPASEF and diaPASEF

Recent advancements in mass spectrometry-based proteomics have made it possible to conduct comprehensive protein analysis. In particular, the emergence of the data-independent acquisition (DIA) method powered by machine learning has significantly improved protein identification efficiency. However, compared with the conventional data-dependent acquisition (DDA) method, the degree to which peptides are uniquely identified by DIA and DDA has not been thoroughly examined. In this study, we identified over 10,000 proteins using the DDA and DIA methods and analyzed the characteristics of unique peptides identified by each method. Results showed that the number of peptides uniquely identified by DDA and DIA using the same column type was 19% and 32%, respectively, with shorter peptides preferentially detected by the DIA method. In addition, more DIA-specific peptides were identified, especially during the first 10% of elution time, and the overall 1/K0 and m/z shifted toward smaller values than in the DDA method. Furthermore, comparing the phosphorylation and ubiquitination proteome profiles with those of whole-cell lysates by DDA showed that the enrichment of post-translationally modified peptides resulted in wider m/z and 1/K0 ranges. Notably, the ubiquitin peptide-enriched samples displayed lower m/z values than the phospho-proteome. These findings suggest a bias in the types of peptides identified by the acquisition method and the importance of setting appropriate ranges for DIA based on the post-translational modification of peptide characteristics.

Analisis Peramalan Penjualan untuk Perencanaan Produksi pada Lavanda Brownies Karawang

This research was conducted at Lavanda Brownies Karawang which compared the moving average and exponential smoothing forecasting methods. This research aims to find out, calculate, analyze and explain how to use the moving average and exponential smoothing methods in sales forecasting for production planning at Lavanda Brownies Karawang as well as to find out, calculate, analyze and explain what forecasting method is most appropriate to use for Lavanda Brownies Karawang based on calculations of Mean Absolute Devitiation (MAD), Mean Square Error (MSE), and Mean Absolute Percent Error (MAPE). This research uses a quantitative descriptive method, to get a general picture of the company's condition, a literature review related to the research topic is carried out as well as field research through interviews and direct observation. Based on the research results, the exponential smoothing forecasting method based on alpha 0.9 is the best forecasting method for production planning. This method was chosen because it has the smallest MAD, MSE and MAPE accuracy values ​​when compared to other methods, namely with MAD of 489,909, MSE of 506.950 and a MAPE percentage of 14,14%, which percentage has the smallest value and is included in the category Good. A smaller MAPE accuracy value indicates more precise forecasting. Because in forecasting the smaller the accuracy value, the better the forecasting results so that the Lavanda Brownies business can plan optimal steamed brownie production activities in the next period.

Optimizing Arterial Tissue Thickness Measurement Protocols: Digital Vernier Caliper Versus Digital Thickness Gauge

Background: The aim of this study is to analyze the reproducibility of sample thickness measurements taken by a non-experienced user by comparing a standard digital vernier caliper, with four different protocols, to a specialized thickness gauge. Methods: The current study is a methodological study where we examined the thickness of the porcine arterial wall in the thoracic aorta of six pigs. Two adjacent samples of 10 × 10 mm from each aorta were excised longitudinally from the anterior wall, resulting in twelve specimens. Five protocols were employed to measure the thickness of each sample. In four of these protocols, digital vernier calipers (Multicomp PRO MP012475) were utilized, while the fifth protocol utilized a specialized digital thickness gauge (Mitutoyo 547-500S, Mitutoyo Corp., Kawasaki, Japan). Results: We observed a higher average thickness of the samples during the initial measurement compared to the second measurement (1.11 ± 0.16 vs. 0.94 ± 0.17, p = 0.0319) with the first protocol and smaller values than those determined at the last measurement (0.93 ± 0.15 vs. 1.10 ± 0.15, p = 0.0135) for the third protocol. Further, with the digital vernier calipers, we recorded lower values for all four protocols than for the digital thickness gauge determinations. In addition, we computed the ratio of the thicknesses measured during the first, second, and third measurements to analyze how consistent the values were across the three consecutive measurements, with no difference regarding the third, fourth, and control protocols. Conclusions: The digital thickness gauge offers dependable measurements, regardless of the user’s expertise in assessing tissue thickness, and demonstrates a substantially higher reproducibility when compared to the digital vernier. We also found that taking an average of the thickness measurements from four specific points on each half of the sides or on each diagonal of each corner yielded consistently reliable results over time when using a standard digital vernier caliper instead of a specialized one.

Adsorption Energies of X-Doped Fullerene (X = Si, Sn, BN): A First-Principles Study

The interaction of dopamine and Si-, Sn-, and BN-doped fullerenes was studied by using the density functional theory (DFT). Adsorption energies of dopamine–C60, dopamine–C59Si, dopamine–C58Sn, and dopamine–C58BN were -0.03 eV, -1.46 eV, -0.06 eV, and -0.05 eV, respectively. All systems had negative adsorption energies, indicating that dopamine can be adsorbed on fullerene. Furthermore, dopamine–C59Si had the smallest value and was chemisorbed shown by a created covalent bond between Si of fullerene and N of dopamine. Therefore, C59Si has a plausible potential as a drug carrier for dopamine molecules.

Computational Fluid Dynamics (CFD) in Arteriovenous (AV) Graft Implantation Through End-to-Side Anastomosis with Varying Tube Diameters Across Different Vascular Access Locations for Dialysis Treatment.

Background/Objectives: Arteriovenous (AV) graft is a procedure for hemodialysis performed in the arm. Optimizing AV graft design is vital to enhance haemodialytic efficiency in patients with kidney disease. Despite being a standard procedure, making it work optimally is still difficult due to various graft diameters and anastomosis configurations, which have limited studies. This research aims to find the ideal AV graft tube diameter on blood flow and pressure gradients and the ideal body site for AV graft implantation and to study their angles for dialysate flow. Methods: Nine models were designed in Autodesk Fusion 360 with 40°, 50°, and 60° angles each having 2 mm, 5.1 mm, and 14.5 mm diameters, all following specific equations on continuity, momentum (Navier-Stokes Equation)), and the Reynolds Stress Model (RSM). The CFD simulation of these models was performed in ANSYS Fluent with an established parameter of 0.3 m/s inlet velocity and stiff/no-slip graft and artery wall boundary condition. Results: As a result, the design with a diameter of 14.5 mm and a 40° angle was overall the most ideal in terms of minimal wall shear stress and turbulence. Conclusions: Thus the brachiocephalic area or the forearm is calculated to be the most optimal implantation site. Additionally, varying angles do affect dialysate flow, as smaller values cause less stress.

PERBANDINGAN FUZZY TIME SERIES MARKOV CHAIN DAN FUZZY TIME SERIES CHENG

Investing is a hot and fast-growing topic right now. Stock.investing.is one of the most popular investments by the public. The JCI is an index that measures the performance of all stocks listed on the IDX. The closing price of the stock is published daily and can be used by investors as an investment benchmark. The occurrence of stock price fluctuations entails a high risk of loss. Predicting stock prices is one way to avoid this risk. Fuzzy time series is a time series model that can be used to minimize the risk of future occurrences. Time parameter data is not stationary, so this research uses fuzzy time series with Markov chains and Cheng's method to determine the JCI completion dates from January 2018 to June 2022. Calculating the accuracy level of the two method approaches using symmetric Mean Absolute Percentage Error (sMAPE), the sMAPE value obtained in the Fuzzy Time Series Markov Chain method is 2.11% and the Fuzzy Time Series Cheng method is 2.98%. The conclusion is that of the two methods the Markov Chain has a smaller value and can be said to be a better method compared to the Cheng method.

Composition, divergence and variability: A comprehensive analysis of fish trait responses to connectivity

Connectivity, a fundamental concept in ecology, refers to the extent to which different habitats or ecosystems are interconnected through the movement of organisms, nutrients, and energy. Lateral hydrological connectivity (LHC) plays an especially critical role in shaping aquatic community organization in river-floodplain systems. However, a comprehensive understanding of various trait responses to LHC remains elusive. We characterized how attributes of fish community traits, specifically composition, divergence, and temporal variability respond to LHC in the Austrian-Hungarian floodplains of the Danube River using environmental DNA (eDNA) metabarcoding. Trait composition was quantified by community-level weighted means (CWM) as the degree of changes in trait responses along the LHC gradient from isolated oxbows to the main river. Divergence was measured using Rao’s quadratic functional diversity index and a null model approach to calculate standardized effect sizes (SES), with larger SES values indicating greater divergence and smaller values indicating convergence. Temporal variability, representing the degree of instability in community traits over time, was calculated using a functional beta diversity measure for multiple communities. Our findings revealed apparent compositional changes for many trait variables, highlighting the significance of LHC in shaping community functional diversity. Divergence patterns indicated that isolated habitats foster trait convergence presumably due to habitat filtering, whereas more connected areas promote trait divergence due to higher species richness and habitat availability. Temporal variability of traits associated with flow preference exhibited a hump-shaped relationship with LHC, suggesting intermediate connectivity zones are hotspots of ecological dynamism. The study suggests that examining composition, divergence, and temporal variability together provides a more complete understanding of trait responses to connectivity, stressing the importance of maintaining diverse connectivity levels in river-floodplain systems for effective conservation and ecosystem management.

Analisis Kualitas Layanan Aplikasi Prestige Di Kabupaten Gresik Menggunakan Metode ServQual

The Prestige application is an online attendance for Gresik Regency ASN. What is the assessment of the feasibility of the functionality of the Prestige Application, and what factors influence employees dissatisfaction with the Prestige Application. In previous research on attendance applications, only regarding the impact of the application on employee performance. This research tests the application functionality, so that it meets what is required. Researchers as instruments and data collectors provide assessments of the Prestige application, finding problems that result in a decrease in the quality of the Prestige application. The ServQual method or what is called the service quality concept is a method used to test the nature of service quality, and involves 90 questionnaire respondents. In this research, it was found that there is no forget password feature, and importantly there is a feature to display the total number of attendance points. The Reliability dimension gets the largest value, and the Empathy dimension gets the smallest value. As input, BKPSDM needs to add a forget password feature and information regarding total employee attendance points.

Nanoscale niobium coatings including superior conducting and corrosion resistance on titanium foil materials for PEMFC bipolar plates

In this work, the nanoscale Nb coating for titanium is fabricated by high power impulse magnetron sputtering technology to enhance its conductivity and corrosion resistance, which is utilized as bipolar plates material. The surface morphology, composition, corrosion resistance and conductivity of specimens with various deposition times were characterized. The results demonstrate that the thickness and roughness of nanoscale coatings increase with deposition time and all the Nb-coated titanium specimens exhibit superior corrosion resistance in 0.5 M H2SO4 solution with 5 ppm HF at 80 °C. The corrosion current density increases and then decreases with deposition time, reaching its smallest value at 600 s (3.07 μA cm−2), which is reduced by 3 orders of magnitude compared to the substrate (387.98 μA cm−2). After potentiostatic polarization experiment (PP) for 12 h, the polarization current density (ipp) of coatings reduces as deposition time increases, with values of 1.54, 0.58, 0.45 and 0.27 μA cm−2, respectively. Furthermore, a low ICR is obtained for fresh Nb-coated titanium specimens, with values of 8.45, 8.95, 3.62 and 3.04 mΩ cm2, respectively. After PP for 12 h, the ICR slightly increase to values of 9.83, 9.63, 6.76 and 6.15 mΩ cm2, which still satisfy the demand of 2025 DOE requirements (≤10 mΩ cm2).

Age-dependent flexion relaxation phenomenon in chronic low back pain patients.

The flexion relaxation phenomenon (FRP) is characterized by suddenly reduced paraspinal muscle activity during full flexion. Previous studies showed significant differences in FRP and flexion angles in chronic low back pain (cLBP) patients compared to individuals without back pain (no-BP). However, the relationship between FRP and flexion angles remains insufficiently understood in older populations. Thus, this study investigated the relationship between FRP and flexion angles concerning to the age and presence of cLBP. Forty no-BP subjects (20m/20f; mean age 41.5years) and thirty-eight cLBP patients (19m/19f; mean age 43.52years) performed maximum full upper body flexion task. Electromyographic (EMG) measurements were conducted to assess the activity of lumbar erector spinae (ESL), thoracic erector spinae (EST), and multifidus (MF). Lumbar, thoracic, and pelvic angles at the onset (OnsetL/T/P) and offset of the FRP (OffsetL/T/P) and maximum trunk inclination (MaxL/T/P) were calculated. The FRP was evaluated using a flexion relaxation ratio (FRR). cLBP patients showed smaller FRR in MF and right ESL compared to no-BP individuals (p < 0.05), while no differences were found in flexion angles between two groups. Subjects over 40 showed smaller FRR in MF and ESL, and smaller flexion angles on OffsetL and MaxL (p < 0.05). Age-related analysis in the cLBP group revealed that patients over 40, compared to younger ones, had smaller FRR in MF and ESL, and smaller values in all thoracic and lumbar flexion angles (p < 0.05). While in no-BP group, significant larger flexion angles in OnsetL and OffsetT (p < 0.05) were observed in participants over 40. Pain-related analysis in the older group revealed that the cLBP patients, compared to no-BP individuals, had smaller FRR in right MF and right ESL, and smaller values in all lumbar and thoracic flexion angles (p < 0.05), while in younger group, there were no significant pain-related differences in FRR, with larger values in all lumbar flexion angles (p < 0.05). Our findings indicate a reduction or absence of FRP in cLBP patients compared to no-BP individuals, with age being a significant factor as those over 40 showed smaller FRP and flexion angles compared to younger individuals.

Non‐Linearity in Mean Annual Peak Flow Scaling With Upstream Basin Area: Insights From Percolation Theory

ABSTRACTUnderstanding how annual peak flow, , relates to upstream basin area, , and their scaling have been one of the challenges in surface hydrology. Although a power‐law scaling relationship (i.e., ) has been widely applied in the literature, it is purely empirical, and due to its empiricism, the interpretation of its exponent, , and its variations from one basin to another is not clear. In the literature, different values of have been reported for various datasets and drainage basins of different areas. Invoking concepts of percolation theory as well as self‐affinity, we derived universal and non‐universal scaling laws to theoretically link to . In the universal scaling, we related the exponent to the fractal dimensionality of percolation, (i.e., ). In the non‐universal scaling, in addition to , the exponent was related to the Hurst exponent, , characterizing the boundaries of the drainage basin (i.e., ). The depends on the dimensionality of the drainage system (e.g., two or three dimensions) and percolation class (e.g., random or invasion percolation). We demonstrated that the theoretical universal and non‐universal bounds were in well agreement with experimental ranges of reported in the literature. More importantly, our theoretical framework revealed that greater values are theoretically expected when basins are more quasi two‐dimensional, while smaller values when basins are mainly quasi three‐dimensional. This is well consistent with the experimental data. We attributed it to the fact that small basins most probably display quasi‐two‐dimensional topography, while large basins quasi‐three‐dimensional topography.

VARIABILITY REGULARITIES OF THE CEPHALOMETRICAL PARAMETERS OF THE HUMAN FETAL SKULL

The purpose of the study – to find out the regularities of the age dynamics of cephalometricparameters and critical periods of the development of the skull of human fetuses.Material and methods. 60 preparations of skulls and 63 computer tomograms of theheads of human fetuses aged from 4 to 10 months of intrauterine development werestudied. A complex of morphological research methods was applied, which includedanthropometry, morphometry, three- dimensional reconstruction and statistical analysis.Linear and angular parameters of the skull were measured, and their ratios, characterizingthe constitutional and cephalometric parameters of the individual (cranial and facialindices), were determined. Results. The analysis of absolute cephalometric parameters (longitudinal, transversediameters, skull circumference, height dimensions) demonstrated the predominanceof logarithmic dynamics of their changes in human fetuses, that is explained by theiraccelerated growth during the 4th month of intrauterine development and a slowdownduring the 7th month with subsequent acceleration in the 8th month of prenatal development.A straight trend line is characteristic of the V-S height (distance from the Sella turcica tothe highest point of the skull), which is explained by the accelerated growth of the anteriorand posterior cranial fossae, while the sphenoid bone and the region of anterior fontanelledevelop in a consistent direction and pace. The linear pattern of growth is typical for theforamen magnum, hard palate, length of the orbit, body and ramus of the mandible, aswell as for relative cephalometric parameters that show a wide range of morphometricvariability. Analysis of the scatter diagram using the method of weighted least squaresdistances showed a decrease in the angle of the front part of the cranial base until the5th month of intrauterine development, followed by an increase in the 7th-8th months ofprenatal development. Multivariate regression analysis of the relationship between fetalage, cranial index and the value of the angle of the front part of the cranial base showedpronounced anatomical variability, which depended on the craniotype. Before the end ofintrauterine development, the N-S-Ba angle increases, but at the beginning of the fetal periodof ontogenesis, it decreases. It has the smallest values in dolichocephals compared to othercraniotypes. The largest values of this angle are found in mesocephals at the beginning of thefetal period, and in brachiocephals and mesocephals at the end of intrauterine development.Conclusions. 1. Critical periods of skull development in the fetal period of humanontogenesis are the 4-5th and 7-8th months, during which uneven changes in absoluteand relative craniometric parameters are observed. 2. The value of the angle of the frontpart of the cranial base can be a diagnostic and prognostic indicator in combinationwith the cranial index, which characterize the craniotype of the individual, during themonitoring of the normal development of the skull and brain of the fetus.

Bearing Capacity and Settlement of Bored Pile Foundation Based On Spt Test Data Aand CPT Test

One form of government effort for the community is the construction of flats. In the construction of Flats X, it is necessary to conduct an analysis in order to minimize the occurrence of foundation collapse beyond the permit limit requirements. In this research analysis using axial and lateral carrying capacity. For axial carrying capacity based on NSPT values using three methods, namely Wright and Reese, Mayerhoff, Luciano Decourt. As well as on shaman power based on the CPT Test using three methods, namely Aoki de Lancer, Mayerhoff, and Schmertmann and Nottingham. For lateral carrying capacity using the calculation of the p-y curve method and using LPille software. For the descent of the foundation using Settle3D. So, obtained in this study for axial carrying capacity taken from three methods in the SPT Test is using the mayerhoff method with the results obtained, namely Q (all press) = 170 tons and Q (all pull) = 85 tons. The axial carrying capacity based on the Cpt Test is obtained from the smallest value in the three methods is the Aoki de Lancer method with the results obtained, namely Q (all press) = 83 tons and Q (all pull) = 14 tons. For lateral carrying capacity using the LPille program, a lateral load of 63.2 kN was obtained. For the number of foundation needed, namely 306 foundations. As well as for the lowering of the foundation obtained using Settle3D which is 96.3 mm.

Frond and mesophyll traits related to photosynthetic capacity and water‐use efficiency in ferns with different life‐forms ex situ

AbstractLeaf traits are known as indicative of species functional properties in angiosperms. Fern fronds are little studied in this concern, especially ex situ. We studied leaf mesophyll structure, pigments and gas exchange in four fern species grown in a glasshouse—Sphaeropteris cooperi (terrestrial tree fern), Phlebodium aureum (semi‐epiphytic herbaceous), Asplenium australasicum (epiphytic shrubby) and Platycerium bifurcatum (epiphytic herbaceous). Saturated assimilation rate (Asat) decreased and intrinsic water use efficiency (iWUE) increased from a terrestrial tree fern to epiphytic ferns. Asat positively correlated with chloroplast number (Nchl/A) and their surface area per leaf area (Achl/A). iWUE negatively related to Nchl/A and chlorophyll/carotenoid ratio. Most differences between species were found in the mesophyll thickness (MT) and mesophyll cell volume (Vcell) with the smallest values in S. cooperi and the largest ones in P. bifurcatum. We found that photosynthetic limitations in ferns were related to the chloroplast photosynthetic activity rather than to Nchl/A or pigment content which did not differ from most angiosperms. Epiphytic ferns showed larger values of Vcell per cell and per chloroplast compared to angiosperms and tree ferns. We concluded that an increase in MT and Vcell in the studied ferns was not associated with photosynthetic performance, but was related to volumetric cytoplasm–chloroplast ratio meaningful to light absorption and the water‐storage function of fern fronds.

Analisis Perbandingan Produktivitas Tukang dan Pekerja Menggunakan Metode Time Study dan Analisis Harga Satuan Pekerjaan 2022

The working time of handymen and workers before project implementation can be calculated from the labor coefficient in units of work quantity so that productivity can be known. However, between productivity based on the 2022 AHSP coefficient and field productivity often experience differences. This study aims to calculate the productivity of handymen and workers using the time study method and the comparison of the productivity of handymen and workers the time study method against the 2022 AHSP labor coefficient in the construction of projects in Palangka Raya City for red brick wall installation work. Data collection techniques with observation by recording work time and quantity of work as well as the number of handymen and workers. The data was analyzed using the time study method assisted by Microsoft Excel. The results showed that worker productivity: 6.38 m2⁄OH and handyman: 5.83 m2⁄OH. Comparison of work productivity using the time study method to the productivity of the 2022 AHSP coefficient in red brick wall installation work shows that worker productivity has a greater value and builders have a smaller value than productivity based on the 2022 AHSP coefficient.

Variations in gust factor with wind direction and height based on the measurements from a coastal tower during three landfalling typhoons

Using high-frequency onshore wind data from four different heights of a coastal tower, the variations in gust factor with turbulence intensity, height and wind speed were studied under typhoon conditions. The gust factor increases with increasing turbulence intensity and, most often, can be described by a linear relationship with the turbulence intensity. The gust factor decreases with height and is relatively small compared with those presented in the national codes and other studies. A value of 2.5 is acceptable for the peak factor, which is close to the recommended value of the national code in China. The gust factor increases with increasing wind speed and is also affected by the wind direction. The gust factor has a value to that of previously published results when the wind flows roughly perpendicular to the shoreline, and has a smaller value when the wind flows roughly parallel to the shoreline. The phenomenon is caused by the confinement of shoreline on the sea wave development. Sea waves tend to propagate normal to the shoreline because of the refraction effect. As a result, a shorter roughness length exists in the parallel direction to the shoreline. It can be further explained by the weakness in the momentum flux exchange between the air and sea based on the wave form drag theory when the wind flows parallel to the shoreline.

Visible-Light-Driven Reduction of CO2 to CO with Highly Active and Selective Earth-Abundant Metal Porphyrin-Conjugated Organic Polymers.

The field of artificial photosynthesis, which focuses on harnessing solar light for the conversion of CO2 to economically valuable chemical products, remains a captivating area of research. In this study, we developed a series of photocatalysts based on Earth abundant elements (Fe, Co, Ni, Cu, and Zn) incorporated into 2D metalloporphyrin-conjugated organic polymers known as MTBPP-BEPA-COPs. These photocatalysts were utilized for the photoreduction of CO2 employing only H2O as the electron donor, without the need for any sacrificial agents or precious-metal cocatalysts. Remarkably, all of the synthesized MTBPP-BEPA-COPs exhibited an exceptional CO2 photoreduction performance only irradiated by visible light. Particularly, upon optimizing the metal ion coordinated with porphyrin units, ZnTBPP-BEPA-COP outperformed the other MTBPP-BEPA-COPs in terms of photocatalytic activity, achieving an impressive CO reduction yield of 152.18 μmol g-1 after just 4 h of irradiation. The electrostatic potential surfaces calculated by density functional theory suggest the potential involvement of metal centers as binding and catalytic sites for the binding of CO2. The calculated adsorption energy of CO2 with ZnTBPP-BEPA-COP exhibited one of the two smallest values. This may be the reason for the excellent catalytic effect of ZnTBPP-BEPA-COP. Thus, the present study not only demonstrates the potential of porphyrin-based conjugated polymers as highly efficient photocatalysts for CO2 reduction but also offers valuable insights into the rational design of such materials in the future.

Modelling of evaporative falling-film heat transfer over a horizontal tube

This article focuses on evaporative falling film heat transfer through numerical simulations. A two-dimensional symmetric liquid film flowing outside a single horizontal tube was simulated using the open-source CFD software OpenFOAM. The Tanasawa model was employed to consider mass transfer at the liquid–vapour interface, and the isoAdvector VOF method was used for interface tracking. The simulations explored the impact of film flow rate, tube surface heat flux, and tube diameter on the liquid film thickness and surface heat transfer coefficient. Additionally, the critical heat flux and operational limits were considered. The results demonstrate the accurate reproduction of evaporative falling film heat transfer performance by the present model. The film thickness exhibits a similar profile to adiabatic and sensible falling film heat transfer but provides smaller values. Similarly, the evaporative heat transfer coefficient exhibits significantly higher values and a gentle peripheral variation. The influence of heat flux on evaporative falling film heat transfer is contingent on the film flow rate; it can either enhance or weaken the process. Notably, a larger tube diameter negatively affects heat transfer, suppressing the impact of heat flux, and also increases the risk of liquid film dryout. For a given film flow rate, the average heat transfer coefficient increases initially, reaches a maximum value, and then decreases as the wall heat flux is increased. The peak heat flux, termed critical heat flux, increases with film flow rate but decreases with tube diameter. An operational limit exists where the heat flux is lower than the critical heat flux and the film flow rate is higher than the critical film flow rate; under these conditions, evaporative falling film heat transfer operates in a fully wetting status.

A quantitative study of the microstructure of Indian Gondwana shale: a fractal and algebraic topology approach

This paper covers a novel micro-level application of image processing in understanding the topological and petrophysical properties of Indian Gondwana shale using X-ray computed microtomography images. The complexity and randomness in the pore system are explained through the concept of fractal dimension (FD). In this paper, a quantitative analysis of 2D and 3D fractal dimensions of pores, grains and interfaces was performed for Indian Gondwana shale, using the box-counting method. A pore network is formed by the connection of many subpore clusters, each with a different volume. Hence, an image segmentation algorithm was applied to label different subclusters, and subsequently an analysis of FD was carried out on such subclusters of pores and grains. We implemented a novel application of Betti numbers (B0, B1 and B2) and Euler characteristics on our sample and calculated the possible flow channels of the sample. The FD of grains was found to be greater than the FD of the pore–grain interfaces, while the FD of pores was found to have the smallest value. Consequently, we also observed how the FD of both pores and grains was majorly controlled by the largest subcluster, and during fluid intrusion we observed a significant decrease in the FD of pores. Finally, the pore network with a larger B0 and larger difference of B1 was proved to be best for the storage of hydrocarbons and for fluid movement along more flow channels.