Non-uniform Patterns Research Articles

Nerve-Sparing Gynecologic Surgery Enabled by A Near-Infrared Nerve-Specific Fluorophore Using Existing Clinical Fluorescence Imaging Systems.

Patients undergoing gynecological procedures suffer from lasting side effects due to intraoperative nerve damage. Small, delicate nerves with complex and nonuniform branching patterns in the female pelvic neuroanatomy make nerve-sparing efforts during standard gynecological procedures such as hysterectomy, cystectomy, and colorectal cancer resection difficult, and thus many patients are left with incontinence and sexual dysfunction. Herein, a near-infrared (NIR) fluorescent nerve-specific contrast agent, LGW08-35, that is spectrally compatible with clinical fluorescence guided surgery (FGS) systems is formulated and characterized for rapid implementation for nerve-sparing gynecologic surgeries. The toxicology, pharmacokinetics (PK), and pharmacodynamics (PD) of micelle formulated LGW08-35 are examined, enabling the determination of the optimal imaging doses and time points, blood and tissue uptake parameters, and maximum tolerated dose (MTD). Application of the formulated fluorophore to imaging of female rat and swine pelvic neuroanatomy validates the continued clinical translation and use for real-time identification of important nerves such as the femoral, sciatic, lumbar, iliac, and hypogastric nerves. Further development of LGW08-35 for clinical use will unlock a valuable tool for surgeons in direct visualization of important nerves and contribute to the ongoing characterization of the female pelvic neuroanatomy to eliminate the debilitating side effects of nerve damage during gynecological procedures.

A novel method to estimate the aggregate pollution index in a typical limestone mining and cement producing environment.

This study presents a novel method to estimate the aggregate pollution index (API) within the residential communities around a limestone mining and cement producing environment. The ranges for the air quality index (AQI), pollution load index in the topsoil (PLIt), pollution load index in the subsoil (PLIs), heavy metal pollution index in the water (HPI), and radiological external hazard index (Hex) were 5.99 to 57.97, 1.65E-07 to 3.6E-04, 1.7E-08 to 3.5E-04, 52.17 to 1053.13, and 0.0694Bq.kg-1 to 0.550, respectively. The AQI, PLIt, PLIs, HPI, and Hex revealed nonuniform patterns of variations across the communities, though there was a significant correlation between the PLIt and the PLIs, and between the HPI and the Hex; and a moderate correlation between the HPI and the AQI, between the HPI and the PLIt, and between the HPI and the PLIs. The measured quality indicators (MQI), and the calculated pollution indices (CPI) were subjected to the multivariate analysis. The principal components (PC) split the ten communities the same way in the CPI and the MQI. The API, using the PC, ranged from 3 to 9. The Afami, Balogun, and Akinbo communities had the highest API, while the Ewekoro and Itori communities had the lowest. The CPI was 41% of the MQI, with respect to the within-cluster variance, indicating that the CPI-based clustering was more reliable. Both the CPI and the MQI attributed a unique pollution signature to the Ewekoro community, while the remaining nine communities shared a common pollution status with the Ibese community.

Spatio-temporal species kinetics, thermal and electrical field evolution in an argon EFCAP under different rates of nitrogen seeding: A one-dimensional simulation study

Nitrogen seeding is crucial in cold plasma devices for production of reactive nitrogen species. Excitation Frequency Controlled Cold Atmospheric Pressure Plasma (EFCAP) devices belong to recent concepts in cold plasma where discharge kinetics can be controlled via tuning of external field frequency. The study presents time dependent modelling of such an atmospheric pressure non-DBD argon discharge between two bare electrodes in one dimension under different rates on nitrogen seeding using commercial software COMSOL Multiphysics version 5.4. A square alternating high voltage power source of frequency 11 kHz and peak voltage of 500V drives the discharge in the model. In every half-period, there is an electrical breakdown. Spatio-temporal variations in the electron density, ion density, electric field, electric potential, and electron temperature are investigated. Observed unique spatial oscillations in the species densities, species temperature and distinct drift in the observed characteristics with different rates of nitrogen seeding are some of the appealing aspects revealed by the study. The excitation and dissociation of molecules, generation and losses of ions, plasma mediated reactions and collisional excitations are accounted elaborately in the model developed. The study could explain the origin of typical non-uniform discharge patterns reported experimentally under different excitation frequencies in EFCAP. Obtained results are expected to be useful for better understanding of device physics towards development of improved cold plasma sources with desired characteristics.

Effectiveness of hyperbaric chamber ventilation.

Hyperbaric chamber ventilation (HCV) refers to the intentional introduction of fresh gas, whether air, oxygen, or heliox, into a pressurised hyperbaric chamber in order to remove stale or otherwise compromised gas. The minimum required continuous HCV rate is usually determined by mathematical models derived from the contaminant mass balance within a well-stirred compartment. Non-uniform contaminant distribution patterns inside a hyperbaric chamber could emerge and invalidate the predictions of well-stirred models. Contaminant distribution was investigated inside a clinical hyperbaric chamber with the aim of comparing well-stirred model predictions with the actual contaminant concentration measurements. Local ventilation effectiveness inside a clinical hyperbaric chamber may be compromised, leading to higher contaminant concentration values compared to the predictions of a mathematical model with a well-stirred assumption. A well-stirred assumption in mathematical models is a useful simplification that allows reasonably accurate estimates of HCV requirements. However, local ventilation effectiveness values in a particular hyperbaric chamber might vary, with the potential for hazardous contaminant accumulation in under-ventilated zones.

Anomaly-Based Ship Detection Using SP Feature-Space Learning with False-Alarm Control in Sea-Surface SAR Images

Synthetic aperture radar (SAR) can provide high-resolution and large-scale maritime monitoring, which is beneficial to ship detection. However, ship-detection performance is significantly affected by the complexity of environments, such as uneven scattering of ship targets, the existence of speckle noise, ship side lobes, etc. In this paper, we present a novel anomaly-based detection method for ships using feature learning for superpixel (SP) processing cells. First, the multi-feature extraction of the SP cell is carried out, and to improve the discriminating ability for ship targets and clutter, we use the boundary feature described by the Haar-like descriptor, the saliency texture feature described by the non-uniform local binary pattern (LBP), and the intensity attention contrast feature to construct a three-dimensional (3D) feature space. Besides the feature extraction, the target classifier or determination is another key step in ship-detection processing, and therefore, the improved clutter-only feature-learning (COFL) strategy with false-alarm control is designed. In detection performance analyses, the public datasets HRSID and LS-SSDD-v1.0 are used to verify the method’s effectiveness. Many experimental results show that the proposed method can significantly improve the detection performance of ship targets, and has a high detection rate and low false-alarm rate in complex background and multi-target marine environments.

Probabilistic similarity of non-uniform corrosion pattern between natural corrosion and accelerated experiment

Concrete structures can be seriously deteriorated by the corrosion of steel reinforcement lasting for decades under realistic environment. It is still controversial whether and how the natural corrosion can be reasonably accelerated in experimental simulation. This paper focuses on the probabilistic similarity of corrosion pattern by comparing the normalized configuration of natural corrosion and galvanic accelerated experiment. The former is obtained by conducting the Monte-Carlo simulation of the electrochemical process based on the meso-scale model of concrete, whist the latter is analysed using digital image correlation method. The results indicated that their number and location of corrosion peaks are statistically consistent. The configurations of corrosion are very likely to be similar within the rear region of steel reinforcement in most cases, whereas possibly to be reversed in the front inward region and front outward region. The similarity is affected by the geometry of designed specimen and humidity of simulated environment.

Optimized Placement of Frost-Measuring Sensors in Heat Exchangers via Image Processing of Frost Formation Pattern.

Heat exchangers (HXs) play a critical role in maintaining human thermal comfort and ensuring product safety and quality in various industries. However, the formation of frost on HX surfaces during cooling operations can significantly impact their performance and energy efficiency. Traditional defrosting methods primarily rely on time-based control of heaters or HX operation, overlooking the actual frost formation pattern across the surface. This pattern is influenced by ambient air conditions (humidity and temperature) and surface temperature variations. To address this issue, frost formation sensors can be strategically placed within the HX. However, the non-uniform frost pattern poses challenges in sensor placement. This study proposes an optimized sensor placement approach using computer vision and image processing techniques to analyze the frost formation pattern. Through creating a frost formation map and evaluating various sensor locations, frost detection can be optimized to control defrosting operations with higher accuracy, thereby enhancing the thermal performance and energy efficiency of HXs. The results demonstrate the effectiveness of the proposed method in accurately detecting and monitoring frost formation, providing valuable insights for sensor placement optimization. This approach presents significant potential in enhancing the overall performance and sustainability of the operation of HXs.

PHM-IRNET: Self-training thermal segmentation approach for thermographic inspection of industrial components

Automating thermographic analysis for industrial and construction inspection is one of the essential aspects of NDT 4.0 in industrial transformation. Thermal segmentation is a preliminary step for characterizing a component’s heat signatures by detecting and extracting thermal patterns. Manual segmentation of areas with distinctive thermal patterns is a time-consuming task that consequently can increase the operation cost. Thus, automatic thermal segmentation can significantly assist companies in avoiding possible misinterpretation and decrease the operation cost. Due to the lack of enough labeled thermal images to train deep neural networks and the fact that, by nature, thermal abnormalities may have non-uniform patterns and form in different shapes and sizes, training a deep neural network can be a challenging task. Moreover, selecting common features can cause possible convergence onto dependency toward specific shapes or patterns. Thus, this paper proposes a self-training thermal segmentation method involving a novel process pipeline for using labeled and unlabeled data for training the presented deep-learning model. The method uses an unsupervised approach for predicting the ground truth in case of unlabeled data before passing the data to the secondary model for segmentation. For this paper, three experiments were conducted to evaluate the method’s performance and provide a comparative analysis with the most recent techniques. The first experiment used a simulated inspection created by COMSOL software. The second experiment employed several plate inspections in several isolated environments. Finally, the third experiment used thermal images acquired during an actual inspection of the piping structure and aerospace components.

Effect of Atmospheric Deposition of Pollutants on the Concentration of Trace Metals on Some Sun-Dried Food Items Dried at a Non-Vehicular Corridor in Ile-Ife Nigeria

The effect of atmospheric pollution on some sun-dried food items in Ile-Ife, Nigeria was investigated. Six farm produce: cassava (Manihot esculenta), plantain (Musa x paradisiaca), white yam (Dioscorea rotundata), yellow yam (Dioscorea cayenensis), red cocoyam (Xanthosoma sagittifolium) and sweet potato (Ipomoea batatas) were exposed, for different hours (0 h, 8 h, 20 h, 32 h, 42 h), to the sun at a location far from vehicular activities. Exposed samples were digested and analyzed for Cu, Zn, Ni, Mn, Cd, and Pb using Atomic Absorption Spectroscopy (AAS). The concentration of Cu, in exposed samples, ranged from mg/kg in sweet potato (32 h exposure) to mg/kg in cocoyam (0 h exposure), while the concentration of Zn ranged from mg/kg in plantain (42 h exposure) to mg/kg in cocoyam (0 h exposure). On the other hand, the concentration of Mn ranged from mg/kg in plantain (42 h exposure) to mg/kg in sweet potato (0 h exposure). Furthermore, the concentration of Ni ranged from mg/kg in yellow yam (32 h exposure) to mg/kg in the plantain (32 h exposure). The concentration of Cd ranged from mg/kg in cassava (32 h exposure) to mg/kg in plantain (20 h exposure). In comparison, the concentration of Pb ranged from mg/kg in cassava (20 h exposure) to mg/kg in plantain (20 h exposure). The study observed that there was no particular pattern in the effect of atmospheric deposition of the pollutants, Cu, Zn, Ni, Mn, Cd, and Pb, on the concentration of these pollutants in the sun-dried farm products, for the different exposure hours. The study believed that the non-uniform pattern could result from differences in the concentrations of the pollutants in the atmosphere. It could also be a result of the different water retention abilities of the respective farm products, which may impact the absorption or evaporation of deposited pollutants on these farm products.

Lateral Torsional Buckling Resistance and Design of High Strength Steel Beams Subjected to Nonuniform Temperature

The mechanical characteristics of high-strength steel (HSS) at high temperatures vary significantly from those of mild steel, so fire design regulations derived from mild steel cannot be transferred to HSS structures. Therefore, this paper investigates the fire resistance of beams made of HSSs, which will facilitate the design and application of HSS structures. Due to the heat dissipation of the concrete floor, steel beams are generally heated from three sides, and the temperature distribution in the steel beam cross-section is nonuniform. For such cases, the fire resistance of HSS beams is assessed using finite element models (FEMs) with nonuniform temperature distribution. A Ramberg–Osgood model was used to predict stress–strain relationships of Q460, Q690, and Q960 HSSs at elevated temperatures, and the model was verified by material tests. In the FEM, the proposed stress–strain relationships of HSSs at elevated temperatures, initial geometric imperfections and residual stress are considered for better accuracy. After verifying the established model against experimental results, the influence of nonuniform temperature distribution, load pattern, steel grade, and slenderness ratio on the resistance of HSS beams is investigated by conducting parametric analyses using the verified FEM. It is found that the critical bending moment of steel beams at elevated temperatures associated with lateral-torsional buckling highly depends on the reduction of elastic modulus of steel. By comparing FEM results with EN 1993-1-2, it is evident that EN 1993-1-2 is unsuitable for assessing the fire resistance of HSS beams. Therefore, the expression specified in EN 1993-1-2 is modified by fitting the finite analysis results to more accurately evaluate the fire resistance of HSS beams considering the nonuniform temperature distribution.

Improved equations of ground pressure for shallow large-diameter shield tunnel considering multiple impact factors

Reasonable estimation of ground pressure is of vital importance for lining segments design in shield tunnelling. With the rapid development of the urban transportation, the diameter of the shield tunnel tends to become larger. The existing prediction of the ground pressure may overestimate the ground pressure of the shallow large-diameter shield tunnel and thus produce higher cost for the shield tunnel construction. To provide more reasonable solution for ground pressure surrounding the shallow large-diameter shield tunnel, a series of improved equations are proposed in this study. The two-stage method with non-uniform displacement pattern through numerical modelling is used to simulate the shield tunnelling at first. Secondly, the effect of multiple impact factors on horizontal and vertical ground pressure at tunnel vault, haunch and invert is analyzed and five key impact factors are determined. Thirdly, a series of improved equations are presented based on a large number of numerical modelling through nonlinear regression analysis. These improved equations can consider the effect of multiple impact factors and predict the ground pressure varying with position which is more realistic for the shallow large-diameter shield tunnel. Therefore, when compared with both the numerical modelling results and field measurements for 70 case histories, the improved equations show good performance. Also, the ground pressure of the above cases is calculated by traditional methods such as overburden pressure, Protodiaconov's formula and so on. By contrast to 7 traditional methods, the improved equations predict more reasonable result of ground pressure. At last, the influence of the tunnel axis depth, tunnel diameter, GAP parameter, ground classification and in-situ coefficient of lateral pressure at rest on the vertical ground pressure at tunnel vault is investigated through the improved equations. The results indicate that the tunnel size is of significant importance to the ground pressure as expected and thus special attention should be paid to shallow large-diameter shield tunnel. However, engineers may save the cost when tunnel diameter outweighs 15 m as ground pressure varies insignificantly. Furthermore, the initial stress as well as the GAP parameter which represents the shield tunnel construction details also play a vital role in ground pressure.

Smart fabric inspection using Mimosa pudica plant

Fabric quality governing and defect detection are playing a crucial role in the textile industry with the development of high customer demand in the fashion market. This work presents fabric defect detection using the sensitive plant segmentation algorithm (SPSA) which, is developed with the sensitive behaviour of the plant biologically named “Mimosa pudica”i. This method consists of two stages. The first stage enhances the contrast of the defective fabric image and the second stage segments the fabric defects with aid of SPSA. The proposed work SPSA is developed for defective pixels identification in both uniform and non-uniform patterns of fabrics. In this work, SPSA has been done by checking with devised condition, correlation and error probability. Every pixel will be checked with the developed algorithm, to get marked either defective or non-defective pixels. The proposed SPSA has been tested on the different types of fabric defect databases and shows a prodigious performance over existing methods like the Differential evolution based optimal Gabor filter model (DEOGF), Gabor filter bank (GFB), Adaptive sparse representation-based detection model (ASR) and Fourier and wavelet shrinkage (FWR).

New tools for the investigation of muscle fiber-type spatial distributions across histological sections

BackgroundThe functional and metabolic properties of skeletal muscles are partly a function of the spatial arrangement of fibers across the muscle belly. Many muscles feature a non-uniform spatial pattern of fiber types, and alterations to the arrangement can reflect age or disease and correlate with changes in muscle mass and strength. Despite the significance of this event, descriptions of spatial fiber-type distributions across a muscle section are mainly provided qualitatively, by eye. Whilst several quantitative methods have been proposed, difficulties in implementation have meant that robust statistical analysis of fiber type distributions has not yielded new insight into the biological processes that drive the age- or disease-related changes in fiber type distributions.MethodsWe review currently available approaches for analysis of data reporting fast/slow fiber type distributions on muscle sections before proposing a new method based on a generalized additive model. We compare current approaches with our new method by analysis of sections of three mouse soleus muscles that exhibit visibly different spatial fiber patterns, and we also apply our model to a dataset representing the fiber type proportions and distributions of the mouse tibialis anterior.ResultsWe highlight how current methods can lead to differing interpretations when applied to the same dataset and demonstrate how our new method is the first to permit location-based estimation of fiber-type probabilities, in turn enabling useful graphical representation.ConclusionsWe present an open-access online application that implements current methods as well as our new method and which aids the interpretation of a variety of statistical tools for the spatial analysis of muscle fiber distributions.

Criminal System Disparity in The Indonesian Immigration Law 2011

The Criminal Provisions in Indonesian Immigration Law of 2011 are designed as acts of legislation for preventing transnational organized crimes in Indonesia. This law has existed for more than 10 years and has been no critical evaluation of the immigration criminal provisions. The construction of the criminal system has a non-uniform pattern of penal policy formation. This research employed the doctrinal research method with deductive reasoning that analyzed Articles on immigration criminal provisions from the perspective of Jeremy Bentham’s theory of punishment analyzing the quality of criminal Articles. The results indicate that there are reactive and not pre-empting immigration criminal provisions, poor criminal provisions during immigration examinations, disparities in Judge’s decisions at courts, varied patterns of punishment and sanctions, and inconsistency of criminal liability arrangements against corporations. Reconstruction of immigration criminal Articles is urged to achieve Bentham’s principles and objectives of the law in sentencing. Criminal Articles should be dominated to prevent cross-border crimes during immigration clearance.

Nonuniform structural properties of wings confer sensing advantages.

Sensory feedback is essential to both animals and robotic systems for achieving coordinated, precise movements. Mechanosensory feedback, which provides information about body deformation, depends not only on the properties of sensors but also on the structure in which they are embedded. In insects, wing structure plays a particularly important role in flapping flight: in addition to generating aerodynamic forces, wings provide mechanosensory feedback necessary for guiding flight while undergoing dramatic deformations during each wingbeat. However, the role that wing structure plays in determining mechanosensory information is relatively unexplored. Insect wings exhibit characteristic stiffness gradients and are subject to both aerodynamic and structural damping. Here we examine how both of these properties impact sensory performance, using finite element analysis combined with sensor placement optimization approaches. We show that wings with nonuniform stiffness exhibit several advantages over uniform stiffness wings, resulting in higher accuracy of rotation detection and lower sensitivity to the placement of sensors on the wing. Moreover, we show that higher damping generally improves the accuracy with which body rotations can be detected. These results contribute to our understanding of the evolution of the nonuniform stiffness patterns in insect wings, as well as suggest design principles for robotic systems.

An edge-located uniform pattern recovery mechanism using statistical feature-based optimal center pixel selection strategy for local binary pattern

The Local Binary Pattern (LBP) is a commonly used method for texture classification that performs well in terms of feature discrimination. However, (1) LBP can misclassify some important edge-located textures as non-uniform patterns with only one bin in the feature histogram, thus losing their discrimination capability. (2) When center pixel is contaminated by noise, a uniform pattern may be transformed into a non-uniform pattern, which can seriously affect the obtained LBP, thus degrading the classification results. To overcome these drawbacks, an edge-located uniform pattern recovery mechanism using statistical feature-based optimal center pixel selection strategy (SFB-OCPS) is proposed in this paper.To extract the correct edge pixels, we divide the whole texture image into 16 = 4 × 4 sub-images and propose an edge pixel selection strategy (EPSS) based on adaptive quantization with local threshold on each sub-image. Then 3 candidate center pixels constructed by statistical features of the local sampling neighborhood are generated for each edge-located center pixel. After the steps above, the SFB-OCPS strategy is introduced into the LBP-based algorithms. It is possible to recover some important edge-located non-uniform patterns to uniform patterns with an optimal center pixel selection, thus improving feature discrimination capability of the LBP-based algorithms.It should be emphasized that any LBP variants can introduce the proposed SFB-OCPS strategy to achieve the recovery of the edge-located uniform patterns. To validate the effectiveness of the proposed SFB-OCPS strategy, we introduce the SFB-OCPS strategy into the original LBP and 5 representative LBP-based algorithms. Experiments are conducted on 6 representative texture databases. Classification comparison reveals that the introduction of SFB-OCPS strategy can significantly improve the texture classification performance of LBP-based algorithms. Additionally, the noise-robustness of the proposed SFB-OCPS strategy is also verified through a series of experiments.

Thermal management and temperature uniformity enhancement of cylindrical lithium-ion battery pack based on liquid cooling equipped with twisted tapes

BackgroundThe technology of lithium-ion batteries is adopted as a brilliant energy source for electric vehicles because of its outstanding benefits, such as constant power, long shelf life, lightweight, fast and safe charging, etc. A channeled liquid cooling system is one of the forceful techniques in the thermal management of battery packs. MethodsA cooling system equipped with diverse configurations of twisted tapes is established for a battery module consisting of sixteen commercial ICR18650–26 J lithium-ion batteries. First, the effects of the specific design factor of twisted tapes are investigated. Then to improve the temperature uniformity of the module, nonuniform patterns of twisted tapes are introduced. Significant FindingsThe corresponding findings corroborate the effectiveness of using twisted tapes. It is found that the maximum battery temperature can be controlled at around 305 K when the number of twist pitches is seven. However, the results express that the performance changes are not noticeable for increasing this parameter by more than five. It is ascertained that the cooling system with nonuniform twisted tapes is superior to the conventional case. The temperature difference in the battery module is stabilized within 11.25 K by using the twisted tape having an intensified ratio of 1.5.

The Fractured Permian Reservoir and Its Significance in the Gas Exploitation in the Sichuan Basin, China

Large gas reserves have been found in the Permian platform margin of the Kaijiang-Liangping area of the Sichuan Basin in SW China. They are assumed to be a widely developed reef–shoal reservoir. However, the tight matrix reservoir cannot support high gas production using conventional development technology at deep subsurface. In this contribution, we analyze the fractured reservoirs along the strike-slip fault zones using the compiled data of cores, well logging, and production data, and provide a seismic description. It was shown that the fractures and their dissolution developed along the strike-slip fault zones. The porosity and permeability of the fractured reservoir could increase by more than one and 1–2 orders of magnitude, respectively. The seismic anisotropic energy found in the steerable pyramid process suggests that fractured reservoirs have a strong heterogeneity, with a localized fault damage zone. This fracturing has both positive and negative effects, showing varied reservoir parameters in the fault damage zone. The development pattern should adopt a non-uniform well pattern, in order to target the localized “sweet spot” of the fractures in these deep tight matrix reservoirs.

Thermohydraulic Characteristics of Printed Circuit Recuperators in a Supercritical CO2 Brayton Cycle with Nonuniform Minichannels

Supercritical carbon dioxide (SCO2) technologies have been under the spotlight of developed countries because they believe that such applied sciences can be ingenious solutions to resolve energy and environmental problems. The SCO2 power cycle is one of the most promising technologies in this field due to its high efficiency and low expenditure. However, optimal designs of heat exchange devices are a vital issue in the SCO2 power cycle because they account for almost 80% of the capital costs. In this study, the comparison of diverse combinations of convergent and divergent minichannels inside the low temperature recuperator (LTR) and high temperature recuperator (HTR) is suggested to recognize the strengths and weaknesses of nonuniform minichannels at high operating pressures and temperatures. Three-dimensional conjugate simulations are carried out, and existing data in the literature are used to validate the obtained results. The comparison reveals a slight deviation (less than 10%) in temperature and pressure profiles. After the evaluation of the studied cases in terms of thermal and hydraulic characteristics, different criteria are employed to explore optimal combinations of the hot side and cold side minichannels. Totally, the minichannel convergence enhances thermal performance of recuperators (up to 26%), and their divergence improves the hydraulic behavior. Nonetheless, diverging the minichannels imposes greater positive effects than converging them. The overall analysis specifies that the most efficient LTR and HTR would be attained by diverging the hot side minichannel, while the cold side minichannel is kept unchanged. This combination of minichannels allows reaching the highest SCO2 temperature at the outlet of LTR and HTR (456 K and 656 K) with the minimum pressure drops (around 0.02% of inlet pressures) and achieving the best performance indexes (approximately 2). Finally, the comparative study discloses that at low Reynolds numbers (less than 14000 for the hot side and 10000 for the cold side), the nonuniform patterns of minichannels perform better than the complicated structures, such as zigzag, wavy, and other optimized geometries. The average performance enhancements for the hot and cold sides are 36.3% and 37.4%, respectively.

Experimental and numerical investigation of the gap flow between a pusher and a barge in deep and shallow water

The flow in the gap between a pusher boat and a barge of a conventional inland waterway convoy was experimentally and numerically investigated to gain insight into the complex flow pattern and to provide benchmark data for validation of an adequate turbulence model. Two water depths were considered, corresponding to deep water and moderately shallow water conditions. Both cases highlighted the extremely unsteady non-uniform flow pattern in the gap. The collected data were subsequently used to assess a numerical method based on solving the Reynolds-averaged Navier–Stokes (RANS) equations and the Improved Delayed Detached Eddy Simulation (IDDES) technique. Generally, our numerical predictions compared favorably to the experimental data; however, the IDDES method proved to be more accurate, especially in the prediction of the velocity field in the gap region. The IDDES technique was then used to analyze the flow in water depth to draft ratios h/T of 2.14, 1.5, and 1.2. At h/T=1.2, comparatively larger recirculation zones and a massive increase in resistance were observed. Additionally, to quantify the influence of the gap between pusher and barge on resistance in shallow waters, we modified our model by simply covering the gap and then analyzing this modified model by carrying out an additional simulation at h/T=1.2. Covering the gap reduced the overall longitudinal hydrodynamic force acting on the convoy by about 6.5 %.