Velocity Values Research Articles

Clot waveform analysis to differentiate mild, moderate, and severe hemophilia A

Background Clot waveform analysis can be used to evaluate clot formation profiles. This waveform can be obtained from activated partial thromboplastin time (APTT) assays without additional reagents and shows different patterns in hemophilia patients with coagulation factor VIII (F VIII) deficiency or abnormality. Objective To determine the clot wave pattern and its process in clot formation phases (pre-coagulation, coagulation, and post-coagulation) in normal and hemophilia A subjects, analyze for possible correlations between clot wave parameters and F VIII activity, and obtain the pattern of coagulation curves in hemophilia subjects as a step to assess clot waveform analysis as a possible screening tool for hemophilia. Methods In this cross-sectional study, we performed clot wave analysis in 145 adult and pediatric subjects with hemophilia to obtain the clot wave pattern in this condition. Clot wave analysis was also done in 160 subjects with normal hemostasis to obtain reference clot wave parameters. Results In this study, the starting point of coagulation phase in normal subjects was between 30-40 seconds, with a shorter pre-coagulation phase and steeper slope. Hemophilia patients had a longer pre-coagulation phase and flatter slope, especially in severe hemophilia A patients, who had longer and more variable coagulation starting points (P<0.001). The absolute values of maximum coagulation velocity (Min1), maximum coagulation acceleration (Min2), and maximum coagulation deceleration (Max2) of hemophilia A patients were also lower than those of normal hemostasis patients, with lower absolute value seen in severe than in mild-moderate hemophilia A patients. A moderate correlation was found between Min1, Min2, and Max2 with F VIII activity (P<0.001). Conclusion Clot wave analysis may be considered as a method for screening hemophilia patients to distinguish mild-moderate and severe hemophilia A patients in health facilities that lack the ability to perform F VIII assays.

Influence of magneto-hydrodynamic and couple stress squeeze film lubrication on conical bearing-a slip velocity model

This paper explores the impact of MHD couple stress and slip velocity over a conical bearing in the presence of magnetic field. The flow is considered as incompressible. A uniform magnetic field is imposed perpendicular to the bearing alongy-axis. The modified Reynolds equation is solved using appropriate boundary conditions in dimensionless form to find the pressure distribution which is then used to obtain the expression for load carrying capacity paving the way for the calculation of response time. Numerical computations of the results show that the MHD couple stress on the conical bearings indicates that enhances the pressure distribution, load carrying capacity and squeeze film time of the conical bearings. Further, decrease in these characteristics was observed for the increased values of slip velocity and cone angle.

Ultrasonic Velocity of Acrylates with Decane-2-ol at 313.15 K

Thermodynamic data involving ultrasonic velocities of binary liquid mixtures of methyl acrylate, ethyl acrylate and butyl acrylate with decane-2-ol have been measured at 313.15 K and at atmospheric pressure. Study of thermodynamic properties involves challenges of interpreting the excess quantities as a means of understanding the nature of intermolecular interactions among the mixed components. Experimental values of ultrasonic velocities were correlated with recently proposed Jouyban-Acree model. Deviations in isentropic compressibility were calculated and have been fitted to Redlich-Kister polynomial equation. Excess parameters like specific acoustic impendence, intermolecular free length, available volume, intrinsic pressure, molecular association and molar sound velocity were also calculated. Graphical representations of excess derived thermodynamic parameters used to explain the type and extent of intermolecular interactions

Shear-Wave Velocity Data Assists Modeling for Offshore Windfarm Development

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 35354, “Pseudo-3D Underwater Multichannel Analysis of Surface Waves for Offshore Windfarm Development,” by Stephan Unterseh and Luis McArthur, TotalEnergies, and Edouard Mouton, SismOcean. The paper has not been peer reviewed. Copyright 2024 Offshore Technology Conference. _ In the course of a research and development (R&D) project dedicated to quantitative ground modeling, underwater multichannel analysis surface-wave (UMASW) data were acquired within an offshore windfarm area currently in development in the North Sea. The goal of the project described in the complete paper was to test the added value of the shear wave velocity (Vs) interpreted from the UMASW, particularly as a propagation tool of geotechnical information. While UMASW, together with seismic refraction, is regularly used to characterize the ground for burial or trenching purposes, it appears also to bring valuable design parameters for offshore wind turbine foundations. Introduction To investigate the value of Vs in the performance of quantitative ground modeling studies, an internal R&D initiative was launched aimed at acquiring Vs data and the associated uncertainties of foundation depth of an offshore windfarm currently in development. These data will be tested at a later stage for the propagation of geotechnical parameters used in foundation design. The acquisition consisted of obtaining Vs data through UMASW methodologies around two distinct geotechnical boreholes and along a corridor tying the two areas. The UMASW commonly is used in combination with seismic refraction to perform burial assessment analysis of cable or pipeline or to characterize ground conditions before performance of horizontal deviated drilling. Thus, the data acquisition did not require extensive hardware development. A unique pseudo-3D processing technique nevertheless was implemented to allow for 3D data visualization and ground characterization. Site Conditions The selected site lies in the North Sea in water depths ranging from 20 to 30 m. The area was first investigated with standard geophysical techniques. Preliminary geotechnical investigation included 6-m-deep vibrocores and 60-m-deep drilled boreholes, with alternating cone penetration tests and push sampling and coring. P-S logging also was performed at key geotechnical locations to gather 1D primary wave velocities (Vp) and Vs. The seabed generally consists of a thin cover of Holocene dense sand, occasionally with boulders, overlying quaternary subglacial formation deposits, including moraine, gravelly sand, and clays of variable thicknesses. The bedrock is generally Jurassic and includes dense sand; hard clay; weak claystone; and, locally, strong limestone bands. The test locations were selected within the coverage of the geophysical data set in areas where variable lithologies occur and where the seabed was found free of boulders and outcrops because these are detrimental to UMASW acquisition. The lithology of the two boreholes performed within the test area is indicated in Table 1 of the complete paper.

In Vitro Ciclopirox Glucuronidation in Liver Microsomes from Humans and Various Experimental Animals.

Ciclopirox is a widely used antifungal drug, redisposition of which has drawn increasing attentions due to multiple promising activities. The drug undergoes extensive glucuronidation, which acts as a major obstacle in the ongoing novel application and still remains poorly understood. The current study aims to phenotype ciclopirox glucuronidation pathway and as well to decipher the related species differences. Ciclopirox glucuronidation was investigated in liver microsomes from humans (HLM) and various experimental animals. Assays with recombinant uridine diphosphate glucuronosyltransferases (UGTs), enzyme kinetic analyses and selective inhibitors were used to determine the role of individual UGTs in ciclopirox glucuronidation. HLM is highly active in ciclopirox glucuronidation withMichaelis-Menten constant (Km),maximum velocity (Vmax), and intrinsic clearance (CLint)values of 139 μM, 7.89 nmol/min/mg, and 56 μL/min/mg, respectively. UGT1A9 displays by far the highest activity, whereas several other isoforms (UGT1A6, UGT1A7, and UGT1A8) catalyze formation of traced glucuronides. Further kinetic analysis demonstrates that UGT1A9 has a closed Km value (167 μM) to HLM. UGT1A9 selective inhibitor (magnolol) can potently inhibit ciclopirox glucuronidation in HLM with the IC50 value of 0.12 μM. The reaction displays remarkable differences across liver microsomes from mice, rats, cynomolgus monkey, minipig, and beagle dog, with the CLint values in the range of 26-369 μL/min/mg. In addition, ciclopirox glucuronidation activities of experimental animals' liver microsomes were less sensitive to magnolol than that of HLM. Ciclopirox glucuronidation displays remarkable species differences with UGT1A9 as a dominant contributor in humans. It is suggested that the pharmacological or toxicological effects ofciclopirox may be UGT1A9 and species dependent.

Identification and characterization of Lacticaseibacillus rhamnosus HP-B1083-derived β-glucuronidase and its application for baicalin biotransformation

Baicalein, showing higher bioavailability and stronger pharmacological activity, can be obtained via a β-glucuronidase (GUS)-catalyzed transformation of baicalein 7-O-β-D-glucuronide (baicalin). Recently, we have found that the fermentation broth of Lacticaseibacillus rhamnosus HP-B1083 can efficiently convert baicalin to baicalein. In this study, the L. rhamnosus HP-B1083-derived enzyme involved in baicalin biotransformation was identified and characterized. First, the LruidA gene, encoding the responsible enzyme, was cloned and sequenced. Sequence analysis revealed that the deduced enzyme (designated as LrUidA) belonged to the glycosyl hydrolase family 2. The recombinant LrUidA was expressed and purified for characterization. LrUidA had a molecular weight of 70 kDa, with an optimal temperature of 50 °C and pH 4.5. Although LrUidA was susceptible to temperature, it possessed a relative pH stability. Its Michaelis–Menten constant, maximum reaction velocity and catalytic constant values were 9.710 mM, 13.08 mM/min/mg, and 14.95 s−1, respectively. Site-directed mutagenesis experiment results demonstrated that the enzyme reaction uses side chains of E509 and E415 to hydrolyze the glycosidic bond of baicalin and involves three negatively charged residues, E450, D451, and D452, respectively. Surprisingly, biotransformation was performed under optimized reaction conditions by incubating the purified enzyme with 0.1 % baicalin for 4 h, resulting in a considerable conversion ratio of 99 %. Altogether, our findings provide insights into the properties of L. rhamnosus HP-B1083-derived enzyme and expand our understanding regarding using GUS for the industrial production of baicalein.

Resuspension Experiments of Cleanroom Particles

Satellite integration is conducted in a cleanroom to safeguard surfaces and instruments from contamination. Nevertheless, particulate contamination is frequently observed on satellite surfaces and instruments. Flushing, which involves the injection of a gas, is employed to reduce relative humidity and protect hygroscopic elements of the instruments. However, flushing carries the risk of displacing particulate contamination by resuspension. Furthermore, the resuspension of particles may also occur during launch as a result of depressurization and vibrations. The objective of this study was to experimentally investigate the resuspension of typical particles found in satellite assembly cleanrooms. To this end, an experiment was developed that allowed the resuspension to be filmed with high-speed cameras and used to obtain minimum flow velocity values for the resuspension of self-gripping fastener particles and textile fibers. This will help the contamination engineers limit flow velocity levels to avoid recontamination of previously cleaned surfaces. A method was also developed to measure adhesion force as a preliminary estimate to be used in further modeling work.

Assessing the severity of carpal tunnel syndrome during physical examination by measuring two-point discrimination: Post-hoc analysis of prospectively collected data

IntroductionCarpal tunnel syndrome (CTS) commonly presents after distal radius fractures. Assessing its degree of severity is essential to therapeutic decision-making - i.e. operative vs. conservative treatment. The role of the two-point discrimination (2PD) has not yet been evaluated as a potential indicator of severity during physical examination. Therefore, in our cross-sectional study, we aimed to find a correlation between 2PD values and disease severity, based on the gold-standard electromyography and electroneurography (EMG-ENG) and ultrasonography findings. MethodsWe conducted a post-hoc analysis of prospectively assessed CTS patients for 2PD values. We analyzed the correlation between 2PD and EMG-ENG measurement results, patient characteristics, nerve ultrasonography, and relevant CTS questionnaires. CTS severity was determined by EMG-ENG results. The Pearson correlation was calculated between variables. ResultsThe study included 81 patients. The three pre-determined EMG-ENG severity categories showed a significant correlation between both 2PD values and 2PD severity categories (r= 0.29 [0.07–0.48] and r= 0.26 [0.03–0.45]). Distal sensory latency and conduction velocity values correlated significantly with 2PD categories. However, the correlation coefficients (r= 0.25 [0.02–0.46] and r=-0.24 [-0.37–0.07]) were low. The 2PD severity categories showed no significant correlation with the severity assessed by nerve ultrasound (r=-0.07 [-0.38–0.25]). The 2PD values showed a significant correlation between the values of the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire (r= 0.3 [0.06–0.51]). We concluded that the best cut-off value for differentiating severe from non-severe CTS was at the 9.5 mm 2PD cut-off value (sensitivity = 0.65 [0.45–0.81], specificity = 0.71[0.58–0.82], AUC = 0.71 [0.59–0.83]). ConclusionThere is a significant correlation between 2PD values and the severity of carpal tunnel syndrome as determined by EMG-ENG; however, they are not interchangeable. Based on the results of our study, we propose that measuring two-point discrimination may be a quick and easy, reliable and cost-effective screening method to assess the severity of carpal tunnel syndrome following distal radius fractures.

Is there a relationship between vascular flow parameters of carotid arterial system and trigeminal neuralgia?

Aim: To investigate the flow velocity values and resistance parameters determined by carotid artery doppler ultrasonography (DUS) examination in patients with trigeminal neuralgia (TN). Materials and Methods: 79 patients diagnosed with TN and who underwent carotid DUS were included in the study. Spectral examination results were recorded for the TN side and the healthy side. Results: Peak systolic velocity (PSV) internal carotid artery (ICA), resistive index (RI) (ICA) and PSV (ICA)/PSV external carotid (ECA) values in patients were relatively higher in arterial structures on the TN clinical side compared to the healthy side. RI (ICA)/RI common carotid artery (CCA) value was also high in arterial structures on the TN diagnosed side. Conclusion: It was shown that especially ICA flow velocity and vascular resistance parameters increased in the carotid arterial system on the TN side. These findings indicate that flow parameters in the carotid artery system may also be effective in TN pathophysiology.

Left atrial appendage emptying velocity and left ventricular function as predictors of inotropic support in patients undergoing elective off-pump coronary artery bypass grafting

Abstract Background: Patients undergoing elective off-pump coronary artery bypass grafting (CABG) are at risk of hemodynamic instability, ischemia, arrhythmia, and dysfunction. These events need to be managed by pharmacological supports or relieving of mechanical obstruction (octopus) of the heart to maintain the hemodynamic stability. There is a paucity of data on the effect of left ventricular (LV) dysfunction on left atrial appendage (LAA) emptying velocity. We evaluated the relationship between LV function and LAA emptying velocity and requirement of inotropic support perioperatively. Materials and Methods: In this prospective open-label all-comer study, fifty patients undergoing elective off-pump CABG under general anesthesia, we measured LAA emptying velocity by pulsed wave Doppler and evaluated if it could predict the need for inotropes perioperatively. It is a case series of 50 patients without a comparator arm. We measured pulsed wave Doppler across the mitral valve leaflet and early mitral inflow velocity (Evel) and late mitral inflow velocity, tissue Doppler at the lateral annulus of the mitral valve (e’) and also calculated the ratio of Evel and e’. Need for inotrope in the intraoperative and postoperative period was captured perioperatively. Vasoactive-inotropic score (VIS) was calculated for all the patients. Results: The VIS was significant (P < 0.0001, with odds ratio of 131.6 and confidence interval of 95% (0.9–1). However, there was no significant correlation between ejection fraction (EF) and VIS (P = 0.87). In patients with the need of inotropes, LAA emptying velocity was significantly increased in the postgrafting period as compared to the pregrafting period (75.64 cm/s vs. 57.9 cm/s, P < 0.001). Conclusion: The assessment of LAA emptying velocity value was a useful predictor of the need of inotropic support during off-pump surgery, especially during Obtuse marginal and Ramus grafting. This study paves the need of larger case–control studies to validate the findings.

L-carnitine supplementation in conventional slow and ultra-rapid freezing media improves motility, membrane integrity, and fertilizing ability of dog epididymal sperm

This study aimed to assess the impact of L-carnitine (LC) supplementation in conventional-slow (CS) and ultra-rapid (UR) freezing media on post-thaw quality and fertilizing ability of dog epididymal spermatozoa. Sperm samples were collected from 60 epididymides obtained from 30 adult orchiectomized dogs via retrograde flushing. Twenty pooled sperm samples were then created (3 epididymal samples/pool). Four treatments were established according to the freezing method (CS and UR) and LC supplementation (5 and 0 mM [control, Co]): CS-LC5, CS-Co, UR-LC5, and UR-Co. The CS freezing involved exposing 0.25 mL straw to liquid nitrogen vapors (LN2), while UR freezing submerged 30-µL drops of sperm samples directly into LN2. Sperm kinematics, membrane integrity, and fertilizing ability (by heterologous in vitro fertilization using bovine oocytes) were evaluated for all treatments. Post-thaw results revealed that the CS freezing treatments resulted in significantly higher values (P < 0.05) of curvilinear and average-path velocities, and beat-cross frequency compared to the UR freezing treatments, regardless of LC supplementation. The CS-LC5 and UR-LC5 treatments cryoprotected the sperm by increasing (P < 0.05) the percentage of ‘live-sperm/intact-acrosome’ compared to their controls treatments CS-Co and UR-Co. Regarding fertilizing ability, the CS-LC5 treatment yielded a higher percentage (P < 0.05) of pronuclei formation compared to both UR treatments. The UR-LC5 treatment, however, obtained greater percentage (P < 0.05) than their control UR-Co. In conclusion, supplementation with L-carnitine in conventional-slow and ultra-rapid freezing improved sperm motility, plasma, and acrosome membranes integrity and fertilizing ability of dog epididymal spermatozoa.

Rapid Response of Daphnia magna Motor Behavior to Mercury Chloride Toxicity Based on Target Tracking.

A rapid and timely response to the impacts of mercury chloride, which is indispensable to the chemical industry, on aquatic organisms is of great significance. Here, we investigated whether the YOLOX (improvements to the YOLO series, forming a new high-performance detector) observation system can be used for the rapid detection of the response of Daphnia magna targets to mercury chloride stress. Thus, we used this system for the real-time tracking and observation of the multidimensional motional behavior of D. magna. The results obtained showed that the average velocity (v¯), average acceleration (a¯), and cumulative travel (L) values of D. magna exposed to mercury chloride stress changed significantly under different exposure times and concentrations. Further, we observed that v¯, a¯ and L values of D. magna could be used as indexes of toxicity response. Analysis also showed evident D. magna inhibition at exposure concentrations of 0.08 and 0.02 mg/L after exposure for 10 and 25 min, respectively. However, under 0.06 and 0.04 mg/L toxic stress, v¯ and L showed faster toxic response than a¯, and overall, v¯ was identified as the most sensitive index for the rapid detection of D. magna response to toxicity stress. Therefore, we provide a strategy for tracking the motile behavior of D. magna in response to toxic stress and lay the foundations for the comprehensive screening of toxicity in water based on motile behavior.

STELLA Lightcurves of Energetic Pair-instability Supernovae in the Context of SN2018ibb

SN2018ibb is a recently observed hydrogen-poor superluminous supernova that appears to be powered by the decay of 30 M ⊙ of radioactive nickel. This supernova has been suggested to show hybrid signatures of a pair-instability supernova and an interacting supernova. In a previous paper, we found that rotating, metal-enriched pair-instability supernova progenitors appeared to check both of these boxes. In this paper, we model the lightcurves of the pair-instability supernovae using STELLA. We find that the STELLA models can explain the overall shape of the bolometric lightcurve of SN2018ibb, though not specific morphological features such as the luminosity peak or the bump at roughly 300 days after the peak. We also estimate the contribution from interaction and find that with relatively low wind velocities, the circumstellar medium originating from the stellar winds is consistent with the evidence for interaction in the spectra. The observed values of the photosphere velocity in the 100 days after peak luminosity are similar to the STELLA models, but the deceleration is lower. This leads to the biggest inconsistency, which is the blackbody temperature of SN2018ibb being much hotter than any of the STELLA models. We note that this high temperature (and the flat velocity) may be difficult to reconcile with the long rise time of SN2018ibb, but nevertheless conclude that if it is accurate, this discrepancy represents a challenge for SN2018ibb being a robust PISN candidate. This result is noteworthy given the lack of other scenarios for this supernova.

Thermal slip and variable viscosity analysis on heat rate and magnetic flux through accelerating non-conducting wedge in the presence of induced magnetic field

The focus of present study is to incorporate the variable viscosity and temperature slip impact on heating rate and induced magnetic gradient along the moving non-conducting wedge under magnetic field. In industrial and engineering procedures, the impact of induced magnetization improves the efficiency of thermal systems to main the heating rates. The similarity transformations and stream functions are applied to reduce the governing equations into ordinary form. During this transformation, the pertinent parameters such as wedge parameter, moving parameter, Prandtl factor, viscosity parameter and temperature-slip parameter is obtained. These parameters play a prominent role on the physical values of fluid velocity, induced magnetic field and temperature distributions. The skin friction, Nusselt coefficient and induced magnetic gradient are incorporated through these parameters. The numerical values are executed by using the Keller box analysis with Newton–Raphson technique. It is depicted that the maximum slip in fluid velocity and temperature distribution is obtained for each values of thermal-slip parameter. It is noticed that maximum magnitude in induced magnetic field is reported for each wedge factor. The maximum velocity slip and temperature slip is observed for each choice of moving parameter. It is reported that the maximum variation in heating rate and induced magnetic gradient is obtained for magnetic force and viscosity parameter. The enhancing behavior of skin friction is observed for maximum values of Prandtl number.

Study on the changing patterns of production performance of laying hens and their relationships with environmental factors in a large-scale henhouse

The production performance of laying hens is influenced by various environmental factors within the henhouse. The intricate interactions among these factors make the impact process highly complicated. The exact relationships between production performance and environmental variables are still not well understood. In this study, we measured the production performance of laying hens and various environmental variables across different parts of the henhouse, evaluated the weight of each environmental variable, and constructed a laying rate prediction model. Results displayed that body weight, laying rate, egg weight and eggshell thickness of hens decrease gradually from WCA to FA (P < 0.05). Serum levels of FSH and LH, as well as antibody level of H5 Re-13, gradually decrease from WCA to FA (P < 0.05). Moreover, the values for temperature (T), temperature-humidity index (THI), air velocity (AV), carbon dioxide (CO2), and particulate matter (PM2.5) gradually increase from WCA to FA (P < 0.05). Conversely, the relative humidity (RH) value gradually decreases from FA to WCA (P < 0.05). Additionally, the weights of the environmental variables, determined using a combination of the grey relational analysis (GRA) and analytic hierarchy process (AHP), were as follows in descending order: RH, THI, T, light intensity (LI), AV, PM2.5, NH3, and CO2. When the number of decision trees in the laying rate prediction model was set to 2,500, the results displayed a high level of agreement between the model's predictions and the observed outcomes. The model's performance evaluation yielded an R2 value of 0.89995 for the test set, suggesting strong predictive effects. In conclusion, the current study revealed significant differences in both the production performance of laying hens and the environmental variables across different parts of the henhouse. Furthermore, the study demonstrated that different environmental factors have distinct impacts on laying rate, with humidity and temperature identified as the primary factors. Finally, a multi-variable prediction model was constructed, exhibiting high accuracy in predicting laying rate.

Estimating velocity distribution and flood discharge at river bridges using entropy theory – insights from computational fluid dynamics flow fields

Abstract. Estimating the flow velocity and discharge in rivers is of particular interest for monitoring, modeling, and research purposes. Instruments for measuring water level and surface velocity are generally mounted on bridge decks, and this poses a challenge because the bridge structure, with piers and abutments, can perturb the flow field. The current research aims to investigate the applicability of entropy theory to estimate the velocity distribution and the discharge in the vicinity of river bridges. For this purpose, a computational fluid dynamics (CFD) model is used to obtain three-dimensional flow fields along a stretch of the Paglia River (central Italy), where a historical multi-arch bridge strongly affects flood flows. The input data for the entropy model include the cross-sectional bathymetry and the surface velocity provided by the numerical simulations. A total of 12 samples, including three different flow conditions at four cross-sections, one upstream and three downstream of the bridge, are considered. It is found that the entropy model can be reliably applied upstream of the bridge, also when forced with a single (i.e., the maximum) value of the surface velocity, with errors on total discharge below 13 % in the considered case. By contrast, downstream of the bridge, the wakes generated by the bridge piers strongly affect the velocity distribution, both in the spanwise and in the vertical directions and for very long distances. Here, notwithstanding the complex and multimodal spanwise distribution of flow velocity, the entropy model estimates the discharge with error lower than 8 % if forced with the river-wide distribution of the surface velocity. The present study has important implications for the optimal positioning of sensors and suggests the potential of using CFD modeling and entropy theory jointly to foster greater knowledge of river systems.

Determining the geomechanical units using rock physics methods

The stability of the drilled wellbores in carbonate formations is of great importance. This paper is a new approach to determine the elastic properties of the wellbore based on rock physics methods using the Hashin-Shtrikman bounds to determine the wellbore stability. Initially, the static elastic parameters were determined by two different methods, namely the rock physics method and DSI log, followed by clustering through Multi-Resolutional Graph-Based clustering (MRGC) and calculating geomechanical-units (GMUs) of each method separately. The obtained results from DSI log and rock physic methods were then compared followed by determining the wellbore stability. The results showed that the correlation between shear and compressional wave velocity obtained from the petrophysical method with the measured values of shear and pressure wave velocity in the well was 0.94 and 0.90, respectively, which shows that the petrophysical method can estimate these two logs with high accuracy, and it can be a suitable alternative instead of using the Dipole Shear Sonic Imager (DSI). It was observed that the geomechanical units of elastic parameters calculated by proposed rock physics method are in good agreement with those obtained from DSI log. Rock-physic method can be a good alternative for when expensive DSI logs are missing.

Polydopamine-functionalized polyethersulfone membrane: A paradigm advancement in the field of α-amylase stability and immobilization

Biocatalytic membranes have great potential in various industrial sectors, with the immobilization of enzymes being a crucial stage. Immobilizing enzymes through covalent bonds is a complex and time-consuming process for large-scale applications. Polydopamine (PDA) offers a more sustainable and eco-friendly alternative for enzyme immobilization. Therefore, surface modification with polydopamine as mussel-inspired antifouling coatings has increased resistance to fouling. In this study, α-amylase enzyme was covalently bound to a bioactive PDA-coated polyethersulfone (PES) membrane surface using cyanuric chloride as a linker. The optimal activity of α-amylase enzyme immobilized on PES/PDA membrane was obtained at temperature and pH of 55°C and 6.5, respectively. The immobilized enzyme can be reused up to five reaction cycles with 55 % retention of initial activity. Besides, it maintained 60 % of its activity after being stored for five weeks at 4°C. Additionally, the immobilized enzyme demonstrated increased Michaelis constant and maximum velocity values during starch hydrolysis. The results of the biofouling experiment of various membranes in a dead-end cell demonstrated that the PES membrane’s water flux increased from 6722.7 Lmh to 7560.2 Lmh after PDA modification. Although α-amylase immobilization reduced the flux to 7458.5 Lmh due to enhanced hydrophilicity, compared to unmodified membrane. The findings of this study demonstrated that the membrane produced through co-deposition exhibited superior hydrophilicity, enhanced coating stability, and strong antifouling properties, positioning it as a promising candidate for industrial applications.

Estimation of Friction for a Hydrodynamic Sliding Bearing for the Turbulent Regime From Single-Phase and Two-Phase Fluid Flow Behaviour

The hydrodynamic plain bearing relies on the generation of a lubricant film through the rotational movement of the journal. As the journal rotates, it creates a layer of lubricant between the bearing and journal surfaces. This lubricant film separates the two surfaces, preventing direct contact and minimizing friction and wear. The high speeds can lead to severe conditions such as cavitation due to rapid oil evaporation, which introduces a new phase into the flow. In this study, it is anticipated that a two-phase flow will occur through the shaft-bushing conjunction because of the rupture of the lubricating film near the contact outlet. Pressure disturbances above these rupture zones may induce vapor-cavity formation at a small scale. A numerical analysis was conducted by solving Navier–Stokes continuity equations and vapor-transport equations. The k-epsilon model was used to analyze friction at the fluid-bearing interface for the turbulent regime. The results indicate that higher flow velocity values and pressure were observed in the case of two-phase flow compared to one-phase flow.

Analysis and optimization of vibration characteristics of gyratory crusher based on DEM-MBD and PSO

Dynamic analysis and optimization can improve the stability of gyratory crushers. In this research, a multibody dynamic (MBD) model of a gyratory crusher was built for motion simulation, and the discrete element method (DEM) was applied to describe ore breakage numerically. Specifically, both the stiffness and damping parameters were defined for vibration analysis. A bonding particle model (BPM) was used to extract the distributed breaking force. Then, actual production data was taken to determine the value ranges of key parameters in the established DEM-MBD co-simulation system such as the self-rotation friction coefficient of the mantle, stiffness and damping of the base. Furthermore, the influence of the horizontal stiffness and damping parameters on the vibration of the gyratory crusher was analyzed using the co-simulation results. A dynamic performance prediction model of the gyratory crusher was established using the kriging interpolation method. Finally, based on the prediction model, the particle swarm optimization (PSO) algorithm was applied for the multi-objective optimization of the gyratory crusher. The simulation results indicate that mantle movement is influenced by the horizontal stiffness and damping parameters, which became more complex with the extension of breaking time. The interaction between the stiffness coefficient and the damping coefficient in the Z direction significantly influences productivity. Additionally, horizontal vibrations are significantly affected by the damping coefficient in the Z direction. After optimization, the productivity increased by 10.96 %, the root mean square (RMS) value of the vibration velocity in the X direction decreased by 21.12 %, and that in the Z direction decreased by 4.21 %.