bluuebunny/crossref_metadata_2025_split huggingface dataset:
Can politicians jeopardize public–private partnerships? The case of the Mottarone cable car crash
Authors: Delfino Gianluca F. 
Published: May 2022

AbstractThis study discusses the possible effects of the intervention of politicians—actors that operate above organizations—in the monitoring and execution of public–private partnerships (PPPs). Using the recent case of the Mottarone cable car crash, this research offers evidence that, pressured by private organizations, political actors had both weakened the public sector's ability to effectively monitor the private sector in the execution of PPPs and facilitated private firms in deviating from their contractual obligations. These findings suggest that the interference of the government in PPPs likely has increased the challenges of establishing accountability, and this is also source of ethical issues.
Tobacco harvest phase is critical to runoff and soil loss in conventional tillage system
Authors: Antoneli Valdemir , Bednarz João Anésio , Thomaz Edivaldo Lopes 
Published: May 2022

AbstractSoil erosion in tobacco (Nicotiana tabacum) cultivation has been reported in recent years around the world. Moreover, studies also demonstrated total soil loss during cultivation. In this study, we proposed an assessment of loss of water and soil during the phases of tobacco cultivation. The tobacco cultivation cycle is approximately 180 days in Southern Brazil. We divided this period into 6 phases from planting (September) to the end of the harvest. During the phases, there were variations in soil management, which may indicate different rates of water and soil loss. Gerlach gutters were used to mediate soil and water loss. At each phase of cultivation, we also measured the surface roughness of the soil, water retention, soil exposure, trampling, soil resistance and soil bulk. Our results show that during cultivation the water and soil loss were 10.2% and 62.7 Mg ha−1, respectively. However, the variation of activities during tobacco cultivation indicates different rates of water and soil loss. In the first three phases (90 days after planting), the surface roughness remained high (~19.2%) due to the soil turning, thus reducing the loss of water and soil despite little ground surface coverage. The soil tillage is stopped when the harvest of tobacco begins 120 days after planting. During the harvest, there was an increase in daily activities in the tobacco field, as the leaves were harvested every week, thus reducing soil roughness (~6.8%) and increasing soil density and strength. These conditions increased the rate of soil erosion during harvest. Therefore, the harvest phase is critical to runoff and soil loss.
Preservation of basement architecture in zircon Hf isotope maps
Authors: Hartnady Michael I. H. , Kirkland Christopher L. 
Published: May 2022

AbstractZircon Hf isotopic mapping has been proposed to image large‐scale lithospheric architecture. Here we present zircon Hf isotope maps of the Proterozoic Albany–Fraser Orogen (AFO) in Western Australia, which records a protracted geological history in both extensional and compressional tectonic regimes. The spatial variation in Hf isotope composition of AFO granites is nearly orthogonal to the dominant crustal fabric. Although the 176Hf/177Hf compositions are too juvenile to represent direct melts of the Archaean basement, the variability in 176Hf/177Hf in these AFO magmatic rocks closely mimics the structure of the adjoining Yilgarn Craton. This orogen‐parallel heterogeneity is best illustrated during earliest Palaeoproterozoic magmatic events, which are characterised by low Sr/Y ratios, consistent with tectonic models involving relatively uniform extension along the craton margin during the Palaeoproterozoic. These results demonstrate that regional‐scale zircon Hf variability does not always image coeval lithospheric architecture, but may help illuminate deep basement structure in regions with complex deformation histories.
Importance of antimicrobial stewardship in solid organ transplant recipients: An ESCMID perspective
Authors: Ioannou Petros , Karakonstantis Stamatis , Schouten Jeroen , Kostyanev Tomislav , Charani Esmita , Vlahovic‐Palcevski Vera , Kofteridis Diamantis P. ,   Supported by the ESCMID Study Group for Antimicrobial Stewardship – ESGAP
Published: May 2022

AbstractBackgroundIn the last decades, solid organ transplantation (SOT) has emerged as an important method in the management of chronic kidney, liver, heart, and lung failure. Antimicrobial use has led to a significant reduction of morbidity and mortality due to infectious complications among patients with SOT; however, it can lead to adverse events and drive the development of antimicrobial resistance; thus, antimicrobial stewardship is of extreme importance. Even though there are ongoing efforts of transplant societies to implement principles of antimicrobial stewardship in everyday practice in SOT, there is still a lack of guidelines in this patient population.AimThe aim of this study was to review the status of antimicrobial stewardship in patients with SOT, highlight its importance from the perspective of an ongoing vivid dialogue among ESCMID experts in the field of antimicrobial stewardship, and depict opportunities for future study in the field.ReviewAntimicrobial stewardship programs are important in order to allow appropriate initiation and termination of antimicrobials in SOT recipients, and also aid in the most appropriate dosing and choosing of the route of administration of antimicrobials. Application of already known antimicrobial stewardship principles and application of currently used biomarkers and newly developed molecular rapid diagnostic testing tools can aid to the rationalization of antimicrobial prescribing and to a more targeted treatment of infections. Finally, physicians caring for SOT recipients should be actively involved in antimicrobial stewardship in order to assure optimization of antimicrobial prescribing and become familiar with the principles of antimicrobial stewardship.
Automated Crack Detection With Image Analysis for the Blades of Steam Turbine
Authors: Liu Jun , Wang Huiwen , Jiang Anyao 
Published: May 2022

Abstract
Blades are a critical part of steam turbines. Since they usually work under extremely harsh conditions, it is necessary to detect cracks that are generated during operation in time and prevent them from developing into larger ones. Crack detection is crucial to maintaining the structural health and operational safety of steam turbines. Today, one of the most common detection methods is to perform magnetic particle flaw detection manually, but it is subject to the subjective judgment of inspectors, with a low level of automation. This paper presents an automated crack detection device, which can perform magnetic particle inspection on the blades and transfer images to a host computer for further image analysis. After comparing the performance of different object detection models, yolov4 (you only look once—version 4), which is a fast and accurate real-time object detection algorithm, is chosen in this paper to extract subimages containing cracks on the host computer. Furthermore, an intelligent crack detection model is established from image processing techniques, which can be divided into four steps: image preprocessing, edge detection, crack extraction and crack length calculation. In the step of image preprocessing, a new image pyramid method is proposed to blur the background and eliminate the texture of the metal surface while keeping the cracks' information to the utmost extent. An experimental study shows a reliable performance of the proposed crack detection model.
Nonlinear Normal Modes of a Three Degrees-of-Freedom Cyclically Symmetric Piecewise Linear System
Authors: Kumar Mohit , Sarkar Abhijit 
Published: May 2022

AbstractThis article investigates the nonlinear normal modes (NNMs) of a three degrees-of-freedom cyclically symmetric system with bilinear contact springs. Further, two different cases of zero and nonzero clearance are assumed for the contact model. These systems are found to exhibit qualitatively different characteristics. Interestingly, the former system admits positive-scaling of solutions, which is reminiscent of linear systems. Four classes of NNMs are found for both zero and nonzero clearance. The NNM solutions are calculated using analytical or numerical techniques. The analytical solution involves solving the equations of motion using appropriate ansatzes, while the numerical solution uses a shooting-based continuation scheme. The NNMs' features and their variations with contact spring stiffness and system energy are also studied. This study highlights certain simplifications applicable to cyclically symmetric structures with contact. These simplifications will be of practical interest for designing real-life structures.
Extended State Observer-Based Discrete-Time Sliding-Mode Control With Mismatched Disturbances Attenuation
Authors: Guo Peng , Zhu Limin , Huang Weiwei , Zhang Long , Huang Nuodi , Zhang Yang 
Published: May 2022

Abstract
This paper proposed an extended state observer (ESO)-based discrete-time sliding-mode controller (DSMCer) to improve the steady-state output tracking accuracy of the systems with unmeasurable states and unknown mismatched disturbances. First, an ESO is designed based on disturbance decomposition, which decomposes the lumped disturbances into the matched part and the mismatched part. Instead of regarding all the elements of the lumped disturbance as new states, the proposed ESO regards the first several elements, i.e., the nonzero elements, of the mismatched part of the disturbances as new states. This will result in a smaller dimension and make it easier to guarantee the existence of the ESO. Then, based on the states of the proposed ESO, a new sliding surface is constructed, a new reaching law is designed, and subsequently, a desirable DSMCer is organized, which can solve the problems of unmeasurable states and unknown disturbances and can effectively attenuate the effect of the mismatched part of the disturbances on the output tracking performance. The system stability is analyzed, and the effectiveness of the proposed method is verified through numerical simulations.
A Methodology for the Efficient Quantification of Parameter and Model Uncertainty
Authors: Feldmann R. , Gehb C. M. , Schaeffner M. , Melz T. 
Published: May 2022

AbstractComplex structural systems often entail computationally intensive models that require efficient methods for statistical model calibration due to the high number of required model evaluations. In this paper, we present a Bayesian inference-based methodology for efficient statistical model calibration that builds upon the combination of the speed in the computation of a low-fidelity model with the accuracy of the computationally intensive high-fidelity model. The proposed two-stage method incorporates the adaptive Metropolis algorithm and a Gaussian process (GP)-based adaptive surrogate model as a low-fidelity model. In order to account for model uncertainty, we incorporate a GP-based discrepancy function into the model calibration. By calibrating the hyperparameters of the discrepancy function alongside the model parameters, we prevent the results of the model calibration to be biased. The methodology is illustrated by the statistical model calibration of a damping parameter in the modular active spring-damper system, a structural system developed within the collaborative research center SFB 805 at the Technical University of Darmstadt. The reduction of parameter and model uncertainty achieved by the application of our methodology is quantified and illustrated by assessing the predictive capability of the mathematical model of the modular active spring-damper system.
OBurnett Equations: Thermodynamically Consistent Continuum Theory Beyond the Navier–Stokes Regime
Authors: Jadhav Ravi Sudam , Yadav Upendra , Agrawal Amit 
Published: May 2022

Abstract
Rarefied gas flows are highly nonequilibrium flows whose flow physics cannot be discerned accurately within the framework of the Navier–Stokes equations. The Burnett equations and the Grad moment equations, which form a super-set of the Navier–Stokes equations, have been proposed in the literature to model such flows but not much success has been achieved because of some inherent limitations of these equations. In this review article, we mainly focus on the recently proposed Onsager-Burnett equations (Singh et al., 2017, “Derivation of stable Burnett equations for rarefied gas flows,” Phys. Rev. E 96, p. 013106) for rarefied gas flows, and the progress achieved so far by solving these equations for some benchmark flow problems. Like Burnett and Grad equations, the OBurnett equations form a super-set of the Navier–Stokes equations and belong to the class of higher order continuum transport equations. However, there are two fundamental aspects where the significance of the OBurnett equations is clearly visible. First, the OBurnett equations are unconditionally stable as well as thermodynamically consistent unlike the conventional Burnett and Grad moment equations. Second, the OBurnett constitutive relations for the stress tensor and the heat flux vector do not have any higher order derivatives of velocity, pressure, or temperature. This is quite significant since now the equations need the same number of boundary conditions as that of the Navier–Stokes equations. As such, the OBurnett equations form a complete theory, which cannot be said for the conventional Burnett equations. These two important aspects help to set the OBurnett equations apart from the rest of the higher order continuum theories. The results of the OBurnett equations are compiled for two benchmark rarefied flow problems: force-driven compressible Poiseuille flow and the normal shock wave flow problem. For force-driven compressible Poiseuille flow, the OBurnett equations successfully capture the nonequilibrium effects such as nonuniform pressure profile and presence of normal stresses and tangential heat flux in the flow. The accurate description of highly nonequilibrium internal structure of normal shocks has always been the stringent test for the higher order continuum theories. The results of the OBurnett equations for normal shocks show that there is no theoretical upper Mach number limit for the equations. Further, the equations predict smooth shock structures at all Mach numbers, existence of heteroclinic trajectory, positive entropy generation throughout the shock, and significant improvement over the results of the Navier–Stokes equations. Finally, the recently proposed Grad's second problem, which has the potential to become a benchmark problem, is discussed. The solution of Grad's second problem for different interaction potentials (Maxwell and hard-sphere molecules) within the Burnett hydrodynamics is also presented at length and some important remarks are made in this context.
Heat Transfer Due to Annular Jets Impinging on a Moving Surface
Authors: Dutta Prasun , Chattopadhyay Himadri 
Published: May 2022

Abstract
This work investigates flow and heat transfer under an array of annular jets impinging on a heated moving surface. Numerical solutions of the full Navier–Stokes equation were attempted with a highly refined mesh. This study reports results for Reynolds numbers up to 500. In the surface movement direction, a periodic element from a jet-bank configuration was chosen, and the nondimensional surface velocity was considered from zero (i.e., a stationary plate) to two times the jet velocity. The impact of annular jet impingement over a moving surface on flow and heat transfer characteristics, including the development of the flow field, velocity profiles, skin friction coefficient and topology of skin friction lines, and local as well as surface averaged Nusselt number distribution are presented. It is observed that both the flow field and thermal performance are strongly affected by the surface motion. Heat transfer from the surface initially increases with the increasing surface motion, and after attainment of the highest value, heat transfer reduces with a further increase in surface velocity. However, higher surface velocity leads to higher uniformity in heat transfer, which may be beneficial for situations demanding uniformity in heat transfer.
Modeling and Simulation Study of Dry Ultrasonic Vibration-Assisted Grinding of Tool Steel With Single Alumina Abrasive Grit
Authors: Chaudhari Abhimanyu , Sharma Ashwani , Awale Akash Subhash , Khan Yusufzai Mohd Zaheer , Vashista Meghanshu 
Published: May 2022

Abstract
In the precision fabrication industries, ultrasonic vibration-assisted grinding is widely utilized for the finishing of “difficult-to-cut” materials due to its intermittent cutting mechanism and brittle-to-ductile mode machining. In this study, a two-dimensional finite element model (FEM) of single grit ultrasonic vibration-assisted dry grinding (UVADG) and conventional dry grinding (CDG) of AISI D2 steel has been developed, which taken into account the influence of longitudinal ultrasonic vibration on the workpiece with variable downfeed. The effects of ultrasonic vibration and downfeed on the chip formation mechanism, temperature field, grinding force, and equivalent stress and strain were evaluated by analytical and simulation methods. The results show that the formation of the grinding chips under UVADG is much shorter and straighter than CDG mode at all respective downfeed. The validation experiment compared the simulated and experimental grinding force in both grinding modes to verify the reliability of the FEM results. The validation results demonstrate that the FEM model can accurately describe the single grit UVADG and CDG grinding. At each downfeed, the CDG mode has generated a larger equivalent plastic strain than the UVADG mode, resulting in a higher thermomechanical load on the workpiece. According to the findings, UVADG mode has the least plastic damage on the ground surface, which may improve the surface integrity of the ground component.
A Survey of Wheeled Mobile Manipulation: A Decision-Making Perspective
Authors: Thakar Shantanu , Srinivasan Srivatsan , Al-Hussaini Sarah , Bhatt Prahar M. , Rajendran Pradeep , Jung Yoon Yeo , Dhanaraj Neel , Malhan Rishi K. , Schmid Matthias , Krovi Venkat N. , Gupta Satyandra K. 
Published: May 2022

Abstract
Mobile manipulators that combine base mobility with the dexterity of an articulated manipulator have gained popularity in numerous applications ranging from manufacturing and infrastructure inspection to domestic service. Deployments span a range of interaction tasks with the operational environment comprising minimal interaction tasks such as inspection and complex interaction tasks such as logistics resupply and assembly. This flexibility, offered by the redundancy, needs to be carefully orchestrated to realize enhanced performance. Thus, advanced decision-support methodologies and frameworks are crucial for successful mobile manipulation in (semi-) autonomous and teleoperation contexts. Given the enormous scope of the literature, we restrict our attention to decision-support frameworks specifically in the context of wheeled mobile manipulation. Hence, here, we present a classification of wheeled mobile manipulation literature while accounting for its diversity. The intertwining of the deployment tasks, application arenas, and decision-making methodologies are discussed with an eye for future avenues for research.
Effect of the Streamwise Orientation of a Pair of Vortex Generator on the Flow and Heat Transfer Characteristics in a Plain Channel
Authors: Mehra B. , Simo Tala J. V. , Habchi C. , Russeil S. , Bougeard D. 
Published: May 2022

Abstract
For a rectangular channel flow, a variant of delta winglet vortex generator (VG) in common flow up (CFU) orientation is presented to enhance the thermal performance factor by decreasing the friction losses. The new vortex generator is a simple reversal of a standard CFU orientation such that the leading edge and suction side of the conventional CFU orientation of the winglet become the trailing edge and pressure side for the reverse common flow up (RCFU) orientation of the winglet, respectively. Numerical simulations were carried out for a three-dimensional, steady, laminar, and incompressible rectangular channel flow with and without the two VG configurations. Performance analysis was done for global Nusselt number and friction factor for different inter-winglet spacings of the VG pair at a Reynolds number of 1478. An increase of 2.3% in the thermal enhancement factor was achieved in RCFU compared to CFU orientation at an inter-winglet spacing equal to 0.02 times the channel height. At the highest inter-winglet spacing equal to 0.6 times the channel height, the CFU orientation exhibited a gain of 3.2% in the enhancement factor over the RCFU orientation. Heat transfer downstream of the vortex generator was shown to be impacted in the reverse configuration (RCFU) due to stronger vortex formation compared to a standard CFU configuration at the least inter-winglet spacing.
Validation of a Two-Phase CFD Air/Mist Film Cooling Model With Experimental Details—Part I: Development of an Experimental Test Facility
Authors: Wang Ting , Zhao Lei , Abdelmaksoud Ramy 
Published: May 2022

Abstract
Film cooling is a cooling technique widely used in high-performance gas turbines to protect the turbine airfoils from being damaged by hot flue gases. Motivated by the need to further improve the turbine hot section cooling performance, a mist/air film cooling scheme is investigated. A small amount of tiny water droplets with an average diameter of about 7 µm (mist) is injected into the cooling air to enhance the cooling performance. One key feature in understanding mist cooling is the ability to capture droplet information. In order to thoroughly investigate a two-phase flow, experimental and computational studies are needed. Designing an experimental setup for a two-phase flow experiment is challenging, therefore, the authors will dedicate this paper as Part I to discuss all the challenges faced in order to create a successful experimental facility for air/mist film cooling while Part II will discuss how to conduct a high-fidelity computational model for air/mist film cooling accompanied with a validation study by including detailed experimental conditions. This paper presents the experimental facility and instrumentation of an air/mist film cooling study with both heat transfer and droplet measurements. A wind tunnel system and test facilities are built. A phase doppler particle analyzer (PDPA) system is employed to measure the two-phase flow characteristics, including droplet size, droplet dynamics, velocity, and turbulence. An infrared camera and thermocouples are both used for temperature measurements. An extensive uncertainty analysis is performed to assist in identifying large uncertainty sources and planning for an experimental procedure. It was found during the experiment design process that resolving the mist agglomeration problem is the key in successfully generating a well-controlled mist/air mixture and reducing experimental uncertainties. The test apparatus has proven to serve the purpose well to investigate mist/air film cooling with both heat transfer and droplet measurements. Selected experimental data are presented.