Values Of Radius Research Articles

Charge radius relations derived from the nuclear masses for two neighboring isotopes

In this paper, we get the nuclear mass-density parameter of known mass and known charge radius by using the AME2020 nuclear mass database and the CR2013 nuclear charge radius database. For the nuclei with [Formula: see text], we obtained an empirical formula of the constant parameter equal to 0 for the difference of nuclear mass-density parameter between two neighboring isotope. That is, the nuclear mass-density parameter of the two neighboring isotopes was equal. By using this empirical formula combined with AME2020 and CR2013 databases, the calculated value of 625 nuclear charge radii was obtained. The root-mean-square deviation (RMSD) of nuclear charge radius that we have successfully obtained is [Formula: see text][Formula: see text]fm. In addition, one of the corrections is the neutron factor. This correction is the key improvement which reduces the RMSD to 0.0077[Formula: see text]fm. Considering the neutron shell effect, the different shell ranges were divided into two categories for correction, and the RMSD was reduced to 0.0056[Formula: see text]fm. Based on the revised empirical formula combined with the AME2020 database, the calculated and predicted values of nuclear charge radius were obtained with high accuracy. Some of these predictions are also very consistent with experimental values measured in recent years. In addition, we use BP neural network to study the difference of nuclear mass-density parameter on the basis of two categories. The RMSDs obtained are 0.0028[Formula: see text]fm and 0.0038[Formula: see text]fm, respectively. It can be seen that such a division has a certain degree of reliability and feasibility. These results show that the new relation proposed in this paper has simplicity and reliability, which can be compared with other local nuclear charge radius relations.

Pressure sensor based on two-dimensional photonic crystal ring resonator

This paper proposes a novel pressure sensor utilizing a two-dimensional photonic crystal (2DPC) based on a ring resonator design. The sensor consists of a square ring resonator that is connected to two photonic crystal waveguides. The photonic crystal is comprised of a square lattice of circular Silicon dielectric rods with air serving as a background. The proposed sensor operates within a pressure range of 0 to 6 GPa, corresponding to a wavelength range of 1554 nm to 1569 nm. The band structures and transmission characteristics of the proposed sensor are studied using the plane wave expansion (PWE) and finite-difference time-domain (FDTD) methods. The normalized transmission spectra of the sensor are observed by varying parameters such as the refractive index, radius, lattice constant, and pressure value, resulting in corresponding wavelength shifts. The proposed sensor design offers a compact size, a wide dynamic range of 6 GPa pressure, and a high sensitivity of 3 nm/GPa. These properties make it highly suitable for a range of applications such as high-pressure or stress-sensing, medical applications, and long pipeline strain monitoring.

Energy absorption characteristics of aluminum foam-filled corrugated tube under axial compression loading

To improve the energy absorption characteristics of thin-walled structures and reduce the initial peak compression force and load fluctuation, a novel aluminum foam-filled corrugated tube was proposed in this study. Finite element model validated by quasi-static compression experiments was adopted to investigate the crashworthiness performances of aluminum foam-filled corrugated tubes and their combined energy-absorbing structures. The effects of structure parameters including corrugation radius, wall thickness, corrugation length and corrugation radius increments on axial compression characteristics were investigated through finite element analysis. The results showed that compared with aluminum foam-filled straight tubes, the initial peak compression force of aluminum foam filled corrugated tube was reduced by 22.87 %, the compression force efficiency was increased by 6.69 % and the load fluctuation was reduced by 17.94 %. The smaller the values of corrugation radius, wall thickness and corrugation length, the smaller the initial peak compression force; Because the corrugation radius had a great effect on the peak compression force, the order that the corrugations were compressed into folds can be controlled by designing the corrugation radius; In view of the peak and valley values of compression force, an innovative combination of single tubes with different △H was obtained, which had better energy absorption performance. Compared with a single aluminum foam-filled corrugated tube, the compression force efficiency of the combined structure (△H: 0–5–10) was increased by 18.15 % and the load fluctuation was reduced by 33.60 %. The research results can provide a reference for the design and optimization of energy-absorbing devices.

Anisotropic strange quintessence stars in modified f(R,ϕ) theory of gravity

This paper investigated the anisotropic quintessence stars in the [Formula: see text] theory of gravity, where [Formula: see text] is the Ricci scalar and [Formula: see text] is the scalar potential. We investigated the field equations of the [Formula: see text] theory of gravity by using the Krori–Barua technique. We have determined that all the obtained solutions are free from central singularity and potentially stable. The observed values of mass and radius of the different strange stars Her X1, SAXJ1808.4-3658, and 4U1820-30 have been used to calculate the values of unknown constants in the Krori and Barua metric. The physical phenomena of stars, such as energy density, pressure components, anisotropy, sound speeds, equation of state parameters, energy conditions and redshift have been investigated in detail.

Anisotropic strange stars and its maximum mass in Finch-Skea geometry in dimensions D ≥ 4

In this article, we have demonstrated a stellar model for compact stars in the presence of strange matter embedded in D ≥ 4 dimensional space-time defined by the Finch-Skea metric. To study the relevant physical properties of the interior matter, we consider the equation of state (henceforth EOS) as proposed in the MIT bag model, where B is termed the bag constant. The mass-radius relationship in four and higher dimensions is determined using the range of values of surface density through the relation ρ s = 4B, for which bulk strange matter may be a viable issue for compact objects. Here, we choose the range of B so that stable strange matter may exist relative to a neutron at zero external pressure. We note that a maximum value of the stellar radius exists when B is fixed at a given allowed value for which metric functions considered to be real here. This is the maximum allowed radius in this model, which depends on the surface density of a strange star. In four dimensions, the compactness of a star is found to be greater than 0.33. In the case of higher dimensions (D > 4), we observed different values of compactness. Causality conditions are satisfied interior to the star up to the maximum allowed radius , for which the metric function is real. The validity of the energy conditions, surface redshift and other parameters of the stellar configuration are studied, and new results are found. The stability of the model is also studied.

Molecular dynamics calculations of the enthalpy of vaporization for different water models

Phase-change heat transfer processes involving water play a key role in numerous societal applications, such as electrical power generation, microelectronics cooling, or water desalination. Advanced computational tools, such as molecular dynamics (MD), are increasingly being used to simulate these processes, especially on nanostructured surfaces and in nanoparticle suspensions, to gain insight into the unique nanoscale physics at play. In these studies, it is critical to use models of the water molecule that yield accurate predictions of water’s thermophysical properties, particularly its enthalpy of vaporization. Here, we use MD to determine the enthalpy of vaporization (hfg) for six common water models and four different values of the cutoff radius (i.e., the intermolecular distance beyond which interactions are simplified or ignored). The most accurate prediction of hfg (within 2 % of the value tabulated by ASHRAE) comes from the TIP3P water model with a cutoff radius of 14 Å. We also conducted a preliminary study of the variation of hfg with pressure and found reasonable agreement between simulations and tabulated ASHRAE data (<7% error). This work provides physical insights into the sensitivity of the predicted macroscopic thermophysical properties of water to minute changes in the atomic-level properties and is expected to inform future MD-based studies of phase change processes of water, especially as they occur at elevated pressures and on nanostructured surfaces and in nanoconfined geometries.

Development and Analysis of Outage Probability and Achievable Rate for UAV Relay Implementation in Disaster Areas

Unmanned aerial vehicles (UAV) coupled with wireless networks have offered the potential for forthcoming mobile communications networks. The UAV-assisted wireless communication technology approach is an option for maintaining communication services, one of which is for disaster areas. This study aims to investigate the deployment of UAV-assisted communications in disaster areas. The simulation in this work is focused on investigating the relationship between the UAV’s height or radius and the outage probability and achievable rate. We identifies a UAV that behaves as a relay in a disaster area connected to two users, identified several critical parameters, such as UAV height, radius, and SNR value, and investigated the impact of changing each of them on outage probability and achievable rate values. Finally, we simulates the effect of these critical parameters on outage probability and achievable rate to maximize the use of UAV-assisted communication as a disaster management solution. According to the simulation results, as the signal to noise (SNR) increases, the probability of network communication interference decreases, and the achievable level increases. Moreover, increasing the range of UAVs can improve communication performance by reducing the probability of outages and increasing the achievable rate.

Exploring the low-mass regime of galaxy-scale strong lensing: Insights into the mass structure of cluster galaxies

Context. Several recent studies have highlighted a discrepancy between the strong lensing (SL) properties of observed cluster galaxies and the predictions of Λ cold dark matter (CDM) cosmological hydrodynamical simulations. This discrepancy can be interpreted as the result of observed cluster members being more compact than their simulated counterparts. Aims. In this work, we aim at a direct measurement of the compactness of a few selected galaxy-scale lenses in massive clusters, testing the accuracy of the scaling laws adopted to describe the members in SL models of galaxy clusters. Methods. We selected the multiply imaged sources MACS J0416.1−2403 ID14 (z = 3.221), MACS J0416.1−2403 ID16 (z = 2.095), and MACS J1206.2−0847 ID14 (z = 3.753). Eight multiple images were observed for the first SL system, and six for the latter two. We focused on the main deflector of each galaxy-scale SL system (identified as members 8971, 8785, and 3910, respectively), and modelled its total mass distribution with a truncated isothermal sphere. To account for the lensing effects of the remaining components of the cluster, we took the most accurate SL model of its mass distribution available. To include the uncertainty and the systematics affecting the cluster-scale mass models, we explored the posterior probability distribution of its parameters and extracted 100 cluster mass distributions. For each of them, we optimised the mass parameters of the galaxy-scale lens: the bootstrapping procedure allowed us to obtain a realistic estimate of the uncertainty on their values. Results. We measured a truncation radius value of 6.1−1.1+2.3 kpc, 4.0−0.4+0.6 kpc, and 5.2−1.1+1.3 kpc for members 8971, 8785, and 3910, corresponding to total mass values of M = 1.2−0.1+0.3 × 1011 M⊙, M = 1.0−0.1+0.2 × 1010 M⊙, and M = 6.3−1.1+1.0 × 1010 M⊙, respectively. Alternative non-truncated models with a higher number of free parameters do not lead to an improved description of the SL system and show some parametric degeneracies. We measured the stellar-to-total mass fraction within the effective radius for the three cluster members, finding 0.51 ± 0.21, 1.0 ± 0.4, and 0.39 ± 0.16, respectively. Conclusions. We find that a parameterisation of the physical properties of cluster galaxies in SL models based on power-law scaling relations with respect to the observed total luminosity cannot accurately describe the compactness of the members over their full total mass range. Our results, instead, agree with recent modelling of the cluster members based on the Fundamental Plane relation. Finally, we report good agreement between our predicted values of the stellar-to-total mass fraction within the effective radius and those of early-type galaxies from the Sloan Lens ACS Survey. Our work significantly extends the regimes of the current samples of lens galaxies, towards the mass range that will be probed by the Euclid, Rubin, and James Webb Telescopes.

Acute Corneal Hydrops in Keratoconus Coinciding With COVID-19 Infection.

To the Editor: Acute corneal hydrops (AH), characterized by corneal stromal edema after a Descemet membrane rupture that allows aqueous humor entry, is observed in cases of keratoconus. Patients typically present with rapidly deteriorating visual acuity, photophobia, and pain. A timely diagnosis and management are essential to ruling out other vision-threatening pathologies such as corneal edema, infectious keratitis, uveitis, Fuchs endothelial dystrophy, postoperative edema, and acute transplant rejection. Here we describe a case of AH in a patient with keratoconus coinciding with coronavirus disease 2019 (COVID-19) infection and emphasize the importance of patient education in the context-restricted face-to-face consultations. A 20-year-old healthy man was evaluated regularly every 3 months for keratoconus using visual acuity and refraction assessments and anterior segment optical coherence tomography imaging. He wore corneal rigid gas-permeable contact lenses in both eyes. He also had a mild ocular allergy but no atopy or habit of eye-rubbing. There was no family history of keratoconus. A year earlier, he had an episode of AH in his left eye. While his left eye stabilized after pressure patching, the keratoconus progressed in his right eye. Examination findings at his last visit before the COVID-19 diagnosis included: corrected distance visual acuity with a gas-permeable contact lens of 20/30 (right) and 20/16 (left), anterior keratometry of 66.4 D (right) and 43.5 D (left), the thinnest corneal thickness of 264 mm (right) and 468 mm (left), and posterior “best-fit sphere” 9-mm radius values of 4.88 (right) and 6.46 mm (left). Approximately 2 months after the last follow-up, he developed flu-like symptoms (sore throat and fever) and was diagnosed the next day with COVID-19 on polymerase chain reaction. Two days after symptom onset, he noticed sudden deterioration of vision in his right eye and called our hospital. The cornea specialist in the ophthalmology department made a tentative phone diagnosis of AH based on his ocular history and instructed him to apply a pressure patch with ophthalmic ointment. He was examined at our hospital after 10 days of quarantine. The corrected distance visual acuity of the right eye was 20/2000, while a slitlamp examination revealed corneal protrusion and marked corneal epithelial as well as stromal edema in the right eye. Fluorescein corneal observation showed no epithelial abnormality, and a definitive AH diagnosis was made. Optical coherence tomography imaging revealed a break in Descemet membrane with overlying corneal edema (Supplemental Digital Content Fig. 1, https://links.lww.com/APJO/A179). No abnormality was noted in the left eye. He had received the second COVID-19 vaccine dose 1 month before the viral infection and reported experiencing no vaccine-related complications. On examination a month later, the AH in the right eye had remarkably improved. Various ophthalmic management and care delivery experiences have been reported during the COVID-19 pandemic. Perspectives in corneal crosslinking were reported relating to keratoconus in particular.1,2 To the best of our knowledge, our case is the first of AH with concomitant keratoconus and COVID-19 infection, although it was not possible to demonstrate a clear association among them. A previous history of AH in either eye is a predisposing risk factor for AH.3 This case underscores the importance of informing patients of their disease status and the need to undergo regular examinations. However, patients with COVID-19 may not be able to receive a timely ophthalmic examination. This patient was distressed until the postquarantine ophthalmic examination was performed; however, his previous experience with AH including successful pressure patching was helpful for the clinician and patient, who was better able to understand the extent of his condition and follow the provided instructions. In the absence of a clinical history of keratoconus, effectively managing AH before a face-to-face examination could be performed would have been challenging. Here are summary points of consideration when educating a patient with an acute event during a pandemic setting: Recognize the patient’s distress due to being in isolation during the acute event. Provide clear information about the disease and instructions for its independent management during quarantine. Strict hand hygiene should be thoroughly practiced while applying the pressure patch and patients should keep unwashed hands away from their face at times. Remote management may require conservative management methods. This requires careful consideration, particularly in acute ophthalmic cases. Although keratoconus was previously considered a noninflammatory ectatic corneal disease, recent evidence shows a relationship between its pathogenesis and chronic inflammatory events.4,5 Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is known to cause a proinflammatory state.6 There are several reports of corneal graft rejection in patients infected with COVID-19.6–8 Large population-based case-control studies are needed to investigate the possible association between AH in keratoconus and the SARS-CoV-2 cytokine response. Shizuka Koh, MD, PhD*† Takeshi Soma, MD, PhD† Vishal Jhanji, MD‡ Kohji Nishida, MD, PhD†

An Application Study of Improved Iris Image Localization Based on an Evolutionary Algorithm

This study aims to enhance the localization of the inner and outer circles of the iris while addressing issues of excessive invalid computations and inaccuracies. To achieve this objective, diverse methods are employed to improve the process to varying extents. Initially, the image undergoes pre-processing operations, including grayscale conversion, mathematical morphological transformation, noise reduction, and image enhancement. Subsequently, the accurate localization of the inner and outer edges is achieved by applying algorithms such as Canny edge detection and the Hough transform, allowing for the determination of their corresponding center and radius values within the iris image. Lastly, an improvement is made to the particle swarm optimization algorithm by combining various algorithms, namely LinWPSO, RandWPSO, contraction factor, LnCPSO, and AsyLnCPSO, employing mechanisms such as simulated annealing and the ant colony algorithm. Through dual validation on the CASIA-Iris-Syn dataset and a self-built CASIA dataset, this approach significantly enhances the precision of iris localization and reduces the required iteration count.

Three-dimensional evaluation of the transverse rotator cuff muscle's resultant force angle in relation to scapulohumeral subluxation and glenoid vault morphology in nonpathological shoulders

Static posterior subluxation of the humeral head (SPSH) results in glenohumeral osteoarthritis. Treatment strategies for SPSH with or without resulting osteoarthritis remain challenging. There is growing interest in evaluating the rotator cuff muscle volume, fatty infiltration, or forces in osteoarthritic shoulders with SPSH, mainly due to a possible transverse force imbalance. In nonpathological shoulders, the transverse angle of the rotator cuff muscle's resultant force may be associated with scapulohumeral alignment and glenoid vault morphology, despite an assumed transverse force balance. The purpose of this study was to assess the transverse rotator cuff muscle's resultant force angle (TRFA) and its relationship with the scapulohumeral subluxation index (SHSI) and selected glenoid vault parameters using computer modeling. Computed tomography scans of 55 trauma patients (age 31±13years, 36 males) with nonpathological shoulders were analyzed and all measurements performed in 3-dimension. We placed landmarks manually to determine the humeral head center and the rotator cuff tendon footprints. The contours of the rotator cuff muscle cross-sectional areas were automatically predicted in a plane perpendicular to the scapula. Each rotator cuff muscle was divided into virtual vector fibers with homogeneous density. The resultant force vector direction for each muscle, corresponding to the rotator cuff action line, was calculated by vectorially summing the normalized fiber vectors for each muscle, weighted by the muscle trophic ratio. The resultant force vector was projected on the axial plane, and its angle with the mediolateral scapular axis was used to determine TRFA. The SHSI according to Walch, glenoid version angle (GVA), glenoid anteroposterior offset angle (GOA), glenoid depth, glenoid width, and glenoid radius were also evaluated. The mean values for TRFA, SHSI, GVA, GOA, glenoid depth, glenoid width, and glenoid radius were 7.4±4.5°, 54.3±4.8%, -4.1±4.4°, 5.1±10.8°, 3.3±0.6mm, 20±2mm, and 33.6±4.6mm, respectively. The TRFA correlated strongly with SHSI (R=0.731, P<.001) and GVA (R=0.716, P<.001) and moderately with GOA (R=0.663, P<.001). The SHSI was strongly negatively correlated with GVA (R=-0.813, P<.001) and moderately with GOA (R=-0.552, P<.001). The GVA correlated strongly with GOA (R=0.768, P<.001). In contrast, TRFA, SHSI, GVA, and GOA did not correlate with glenoid depth, width, or radius. Despite an assumed balance in the transverse volume of the rotator cuff muscles in nonpathological shoulders, variations exist regarding the transverse resultant force depending on the SHSI, GVA, and GOA. In healthy/nonosteoarthritic shoulders, an increased glenoid retroversion is associated with a decreased anterior glenoid offset.

Quantitative Prediction of Rock Pore-Throat Radius Based on Deep Neural Network

Pore-throat radius is one of the key parameters that characterizes the microscopic pore structure of rock, which has an important impact on oil-gas seepage and the prediction of remaining oil’s microscopic distribution. Currently, the quantitative characterization of a pore-throat radius mainly relies on rock-core experiments, then uses capillary pressure functions, e.g., the J-function, to predict the pore-throat radius of rocks which have not undergone core experiments. However, the prediction accuracy of the J-function struggles to meet the requirements of oil field development during a high water-cut stage. To solve this issue, in this study, based on core experimental data, we established a deep neural network (DNN) model to predict the maximum pore-throat radius Rmax, median pore-throat radius R50, and minimum flow pore-throat radius Rmin of rocks for the first time. To improve the prediction accuracy of the pore-throat radius, the key components of the DNN are preferably selected and the hyperparameters are adjusted, respectively. To illustrate the effectiveness of the DNN model, core samples from Q Oilfield were selected as the case study. The results show that the evaluation metrics of the DNN notably outperform when compared to other mature machine learning methods and conventional J-function method; the root-mean-square error (RMSE), mean absolute error (MAE), and mean absolute percentage error (MAPE) are decreased by 14–57.8%, 32.4–64.3% and 13.5–48.9%, respectively, and the predicted values are closer to the true values of the pore-throat radius. This method provides a new perspective on predicting the pore-throat radius of rocks, and it is of great significance for predicting the dominant waterflow pathway and in-depth profile control optimization.

Numerical Study of the Plastic Zone at the Crack Front in Cylindrical Aluminum Specimens Subjected to Tensile Loads.

Cylindrical specimens are of great interest in analyzing mechanical elements' behavior and investigating phenomena with biaxial loads. It is necessary to identify the behavior of the crack front along the thickness to interpret these results, which are usually based on the hypothesis of a straight crack and the observation of the outer face of the crack front. Based on the work carried out on compact tension type specimens, this work proposes adapting this methodology to cylindrical specimens, adapting the previous finite element models. Cylindrical specimens provide an asymmetric behavior influenced by the radius, where the CT (compact tensile) specimen can be considered the extreme infinite radius case. Combinations of the load level and radius values help us simulate the crack's behavior under intermediate hypotheses between a plane crack theory and a three-dimensional one. The plastic strain around the crack front will be analyzed as a function of the thickness and the load level applied. The results allow us to validate the numerical methodology and establish the differentiated behaviors of the plastic zones close to the outer and inner radii.

Improved Performance of Optical Fiber Core: Role of Plasmonic Metals Activation

Optical fiber core with customized characteristics became demanding for diverse high performance applications. Based on this idea, the optical fiber core was activated using various plasmonic metals (beryllium, chromium, and nickel) to improve its refractive index, sensitivity and bandwidth. The influence of various wavelengths and core radii on three modes (LP01, LP11 and LP21) propagation was determined using finite element analysis (FEM). The COMSOL MULTIPHYSICS software was used for the computation. The fiber core radii of the plasmonic metal activated and wavelengths were varied to control the forward and backward energy propagation as well as the modal dispersion relation. Quantities like effective refractive index, attenuation, propagation constant and diffusion coefficient for the three modes as a function of wavelengths and fiber core radii were calculated, which showed maximum values at shorter wavelengths. Irrespective of the type of metal activation in the fiber core, the refractive index of LP01 mode for the core of radius 200 nm was more significantly affected compared to others. Regardless of different metals inclusion, the dispersion relation (refractive index versus frequency) for all modes was strongly positive, showing increasing values for radius in the order of 200, 400, 600 nm. Plasmonic metals Cr and Ni displayed best effect, while Be required high values of V to get LP01 in a narrow range and other modes appeared in a larger range than V. Present results may be useful for the development of high performance optical fiber core.

Anthropomorphic Characterization of Ankle Joint.

Even though total ankle replacement has emerged as an alternative treatment to arthrodesis, the long-term clinical results are unsatisfactory. Proper design of the ankle device is required to achieve successful arthroplasty results. Therefore, a quantitative knowledge of the ankle joint is necessary. In this pilot study, imaging data of 22 subjects (with both females and males and across three age groups) was used to measure the morphological parameters of the ankle joint. A total of 40 measurements were collected by creating sections in the sagittal and coronal planes for the tibia and talus. Statistical analyses were performed to compare genders, age groups, and image acquisition techniques used to generate 3D models. About 13 measurements derived for parameters (TiAL, SRTi, TaAL, SRTa, TiW, TaW, and TTL) that are very critical for the implant design showed significant differences (p-value < 0.05) between males and females. Young adults showed a significant difference (p-value < 0.05) compared to adults for 15 measurements related to critical tibial and talus parameters (TiAL, TiW, TML, TaAL, SRTa, TaW, and TTL), but no significant differences were observed between young adults and older adults, and between adults and older adults for most of the parameters. A positive correlation (r > 0.70) was observed between tibial and talar width values and between the sagittal radius values. When compared with morphological parameters obtained in this study, the sizes of current total ankle replacement devices can only fit a very limited group of people in this study. This pilot study contributes to the comprehensive understanding of the effects of gender and age group on ankle joint morphology and the relationship between tibial and talus parameters that can be used to plan and design ankle devices.

STRP-DBSCAN: A Parallel DBSCAN Algorithm Based on Spatial-Temporal Random Partitioning for Clustering Trajectory Data

Trajectory clustering algorithms analyze the movement trajectory of the target objects to mine the potential movement trend, regularity, and behavioral patterns of the object. Therefore, the trajectory clustering algorithm has a wide range of applications in the fields of traffic flow analysis, logistics and transportation management, and crime analysis. Existing algorithms do not make good use of the temporal attributes of trajectory data, resulting in a long clustering time and low clustering accuracy of spatial-temporal trajectory data. Meanwhile, the density-based clustering algorithms represented by DBSCAN are very sensitive to the clustering parameters. The radius value Eps and the minimal points number MinPts within Eps radius, defined by the user, have a significant impact on the clustering results, and tuning these parameters is difficult. In this paper, we present STRP-DBSCAN, a parallel DBSCAN algorithm based on spatial-temporal random partitioning for clustering trajectory data. It adopts spatial-temporal random partitioning to distribute balanced computation among different computing nodes and reduce the communication overhead of the parallel clustering algorithm, thus improving the execution efficiency of the DBSCAN algorithm. We also present the PER-SAC algorithm, which uses deep reinforcement learning to combine the prioritized experience replay (PER) and the soft actor-critic (SAC) algorithm for autotuning the optimal parameters of DBSCAN. The experimental results show that STRP-DBSCAN effectively reduces the clustering time of spatial-temporal trajectory data by up to 96.2% and 31.2% compared to parallel DBSCAN and the state-of-the-art RP-DBSCAN. The PER-SAC algorithm also outperforms the state-of-the-art DBSCAN parameter tuning algorithms and improves the clustering accuracy by up to 8.8%. At the same time, the proposed algorithm obtains a higher stability of clustering accuracy.

Significance role of dual porosity and interfacial nanolayer mechanisms on hybrid nanofluids flow: A symmetry flow model

The investigation of heat and mass transfer between two porous disks containing porous media is the focus of this paper. In this research, (Ag–Al2O3/water)-based hybrid nanofluid is used. Governing partial differential equations are converted to nonlinear ordinary differential equations by similarity transformations. Numerical solutions to nonlinear systems of equations are achieved using the shooting technique. It is examined how the particle’s diameter and nanolayer thickness affect the thermal conductivity of a hybrid nanofluid. Due to the increment of nanolayer thickness, the Nusselt number increases and vice versa for the radius of the particle. Tables and graphs show how the governing parameters influence velocity, temperature, and mass concentration profiles, as well as physical quantities such as skin friction coefficient and Nusselt number. As the values of the porous medium parameters ([Formula: see text]–13) and nanolayer thickness ([Formula: see text]–12) elevate, the flow of skin friction coefficient and Nusselt number escalate in both porous disks. Moreover, as the values of the particle radius ([Formula: see text]% to 12%) and Reynolds number ([Formula: see text]1 to 2) amplify, the flow of heat transfer rate is diminished in the lower disk. Porous materials have a high surface area, which increases the contact area between the nanofluids and the porous medium. Porous materials can enhance the permeability of the fluid, reducing the pressure drop in the system. This can be advantageous in applications where high flow rates and low-pressure drops are desired, such as in heat exchangers or cooling systems. Porous materials can provide trapping sites or adhesion points for the nanoparticles, enhancing their dispersion and stability within the hybrid nanofluids. The porosity of the flow medium can therefore influence the purification and filtration efficiency of the hybrid nanofluids, ensuring their cleanliness and functionality. Understanding and controlling the porosity can help optimize the flow characteristics of the nanofluids in various applications. Overall this field will focus on refining hybrid nanofluid compositions, improving modeling techniques, validating experimental findings, optimizing system designs, and exploring new applications.

Coupling of laser diode with cylindrical microlens fabricated on the tip of single-mode photonic crystal fiber: prediction of coupling optics by ABCD matrix

Abstract We report the theoretical prediction of the coupling optics involving a laser diode and photonic crystal fiber which contains on its tip cylindrical microlens. The analysis is based on relevant ABCD matrix formalism. Though photonic crystal fiber has very large single-mode region, we carry on the investigation for two commonly used wavelengths such as 1.3 µm and 1.5 µm. For the particular kind of photonic crystal having specific value of air filling ratio and hole pitch, we have optimized the distance of laser diode from the microlens in order to get maximum value of coupling efficiency for each value of radius of cylindrical microlens. Incidentally, we have got here maximum coupling efficiency to the extent of 86.99 % at the wavelength 1.3 µm when the radius of the cylindrical microlens is 8.5 µm and effective spot size of the fiber is 4.433909 µm. Further, the maximum efficiency becomes 91.78 % at 1.3 µm when the radius of the cylindrical microlens is 4.0 µm and effective spot size of the fiber is 1.859907 µm. It has been shown that wavelength 1.5 µm is not so coupling efficient like 1.3 µm. Moreover, it has been shown that with same set of relevant parameters, PCF is more coupling efficient compared to ordinary graded index fiber. Thus the present work generates scope for varying different photonic crystal fiber parameters and the wavelengths of source as well for enhancing the coupling efficiency. Accordingly, the present analysis will be extremely helpful for design of efficient coupler of this kind.

Microstructure and Corrosion Property of Prepared CoCrW Coatings on the TC4 Surface by Laser Cladding

Ti6Al4V (TC4) is widely used in aerospace, marine equipment, and the petrochemical industry. However, the dense oxide film on the surface of this alloy will be destroyed in reducing acid solution, resulting in surface corrosion in practical application. To enhance the corrosion resistance of TC4 in marine environments, this study employed laser cladding technology to deposit a CoCrW cladding layer on the TC4 alloy surface. Experimental results validated the successful preparation of a dense, crack-free CoCrW layer. The microstructure of the CoCrW layer was characterized by predominant bulk grains and minor equiaxed crystal constituents, demonstrating a robust metallurgical bond to the matrix. Notably, the corrosion resistance of the TC4 surface witnessed a marked improvement, evident from the CoCrW coating’s increased open circuit potential, elevated electrochemical impedance spectroscopy (EIS) radius, phase angle, and impedance modulus values. The corrosion rates of both the TC4 and CoCrW cladding layers escalated with extended immersion time and increased immersion corrosion temperature. However, the CoCrW cladding layer reported minimal mass loss and the least corrosion rate. In summary, the CoCrW coating, when prepared via laser cladding on the TC4 surface, markedly bolstered corrosion resistance.

Application of novel methods for quality improvement in explosion puffing drying of apple snacks

In this study, vacuum drying (VD), microwave drying (MW) and freeze-drying (FD) alternatives to air drying (AD) were applied to apple samples before explosion puffing drying (EPD). The volumes of AD+EPD samples were determined 20% higher than the volume of AD samples. The porosity value and the average pore radius value were obtained by examining the SEM images with the MATLAB program. Porosity values were found between 0.41-0.82 for all drying processes applied. The lowest porosity was found at 180MW, and the highest porosity was found in the FD samples. It is seen that the porosity ratio increases as the microwave power per product increases. Rehydration rates of 180, 360 and 600MW samples were determined as 308, 320 and 336%, respectively. It contributed to the increase in rehydration due to the increase in the porosity of the product with the increase in power density per product in MW drying. There was an increase in the amount of TPC with the combined use of the EPD process. The highest ABTS and DPPH were determined in the FD, FD+EPD and 600MW+EPD samples, respectively. The pre-drying methods and parameters described in the study significantly affected the quality of apples in terms of their physical and chemical properties.