bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tomographic assessment of infrazygomatic crest bone depth for extra‐alveolar miniscrew insertion in subjects with different vertical and sagittal skeletal patterns
Authors: Tavares Alana , Montanha‐Andrade Kátia , Cury Patricia Ramos , Crusoé‐Rebello Ieda , Neves Frederico Sampaio 
Published: April 2021

AbstractObjectiveTo evaluate bone availability at the infrazygomatic crest for extra‐alveolar bone miniscrew insertion in subjects with different vertical and sagittal skeletal patterns.Setting and sample populationMeasurements of the infrazygomatic crest were performed on multislice computed tomography scans from 58 adults with different skeletal patterns.Materials and methodsInfrazygomatic crest bone depth was measured at 4, 5 and 6 mm from the cementoenamel junction (CEJ) of the maxillary first molar at three different angles (60°, 70° and 80°) in the first molar occlusal plane. The sagittal and vertical skeletal patterns were determined. Analysis of variance followed by Tukey's post hoc test was used (P ≤ .05).ResultsBone depth was greater near the CEJ (8.7 ± 3.1 mm) and lower in the apical area (5.8 ± 2.7 mm). In Class II subjects, considering 6 mm from the CEJ, there was a significantly lower depth at the 80° angle (5.4 ± 2.5 mm) than at 60° (8.6 ± 3.5 mm; P = .007). In mesofacial subjects, considering 5 and 6 mm from the CEJ, bone depth was lower at 80° (5.7 ± 3.2 mm and 5.3 ± 2.5 mm) than at 60° considering 4 mm from the CEJ (P ≤ .019).ConclusionBone availability was lower at the apical level, especially in Class II and mesofacial subjects. Therefore, when the planned insertion site is located in the apical direction, it is recommended to choose shorter miniscrews (2.0 x 12mm) and a smaller insertion angle (60°) and/or to plan a miniscrew bone insertion deep enough to allow bicortical fixation.
A replication of “Representative bureaucracy and the willingness to coproduce”
Authors: Sievert Martin 
Published: April 2021

AbstractResearch on symbolic representation suggests that citizen–state interactions might benefit from public organizations' representativeness. Recent experiments on symbolic gender representation provide contradictory findings regarding the influence on citizens' co‐production intentions. This study conducts a wide replication based on new data to reexamine the positive impact of symbolic gender representation identified by Riccucci et al. (2016, Public Administration Review, 76(1), pp. 121–130). The applied survey experiment closely resembles the original design aspects. The experiment is set in criminal justice policy, a policy field featuring co‐production of core public services such as prisoner rehabilitation. The results do not confirm a positive effect of symbolic gender representation on willingness to co‐produce. Instead, several arguments point to citizens' perceptions of uncertainty related to the co‐production context and procedures as a boundary condition for the effects of symbolic gender representation.
China's Pathway to Domestic Emergency Management: Unpacking the Characteristics in System Evolution
Authors: Liu Zezhao , Zhu Zhengwei 
Published: April 2021

China's emergency management (EM) system has undergone a series of reforms and organizational changes since the SARS epidemic in 2003. However, institutional segmentation, unbalanced power for the Emergency Management Office, pervasive internal corruption, and state monopoly control are threats to the administration's goal of resilient and modern EM systems. The new round of 2018 reforms was intended to promote integration through the establishment of the Ministry of Emergency Management and related institutional restructuring involving power redistribution. The reforms are nevertheless likely to face some potential problems like the operation of a super‐ministry, interorganizational integration, state‐society relations, and supervision. Through field interviews, the article investigates and uncovers issues in China's EM system and the perception from government sectors at different levels. The article suggests that cooperative governance in coping with state‐society relations and decentralization of power could be of great significance for future EM reform in China.Related ArticlesAsh, John. 2010. “New Nuclear Energy, Risk, and Justice: Regulatory Strategies for an era of Limited Trust.” Politics & Policy 38 (2): 255‐284. https://doi.org/10.1111/j.1747‐1346.2010.00237.xBrogan, Michael James. 2017. “Evaluating Risk and Natural gas Pipeline Safety.” Politics & Policy 45 (4): 657‐680. https://doi.org/10.1111/polp.12211Neill, Katharine A., and John C. Morris. 2012. “A Tangled web of Principals and Agents: Examining the Deepwater Horizon oil Spill through a Principal–Agent Lens.” Politics & Policy 40 (4): 629‐656. http://onlinelibrary.wiley.com/doi/10.1111/j.1747‐1346.2012.00371.x/full
Bull sperm selection by attachment to hyaluronic acid semi‐interpenetrated hydrogels
Authors: Liaudat Ana Cecilia , Blois Damian , Capella Virginia , Morilla Gricelda , Rivero Rebeca , Barbero César , Rodríguez Nancy , Rivarola Claudia , Bosch Pablo 
Published: April 2021

AbstractWe report the development of a hydrogel‐based approach to select bull spermatozoa, a crucial step for successful assisted reproductive techniques (ARTs). Hyaluronic acid (HA) semi‐interpenetrated N‐isopropylacrylamide (PNIPAM) co‐20% N‐Tris (hydroxymethyl) methyl acrylamide (HMA) hydrogels were synthetized on glass surfaces and cultured in presence of frozen‐thawed bull spermatozoa. A fraction of motile bull spermatozoa population strongly attached to hydrogels and was partially released by treatment with hyaluronidase. Fifty‐nine (59 ± 7.24) per cent of sperm cells attached to PNIPAM‐HMA‐HA hydrogels and 31.16 ± 4.81% of them were released upon treatment with medium containing hyaluronidase. This attached‐released sperm fraction has acceptable characteristics of progressive motility (50.0 ± 5.0%), vigour (4), high viability (58.7 ± 11.7%) and low percentage of acrosome reacted spermatozoa (23.36 ± 4.1%). Our findings indicate that PNIPAM‐HMA‐HA hydrogels are non‐toxic and allow the selection of high‐quality sperm cells for ART.
Prevention of strain‐induced impairments of patellar tendon micromorphology in adolescent athletes
Authors: Mersmann Falk , Domroes Theresa , Pentidis Nikolaos , Tsai Meng‐Shiuan , Bohm Sebastian , Schroll Arno , Arampatzis Adamantios 
Published: April 2021

High‐level patellar tendon strain may cause impairments of the tendon's micromorphological integrity in growing athletes and increase the risk for tendinopathy. This study investigated if an evidence‐based tendon exercise intervention prevents high‐level patellar tendon strain, impairments of micromorphology and pain in adolescent basketball players (male, 13–15 years). At three time points over a season (M1‐3), tendon mechanical properties were measured using ultrasound and dynamometry, proximal tendon micromorphology with a spatial frequency analysis and pain and disability using VISA‐P scores. The control group (CON, n = 19) followed the usual strength training plan, including sprint and change‐of‐direction drills. In the intervention group (INT, n = 14), three sessions per week with functional exercises were integrated into the training, providing repetitive high‐magnitude tendon loading for at least 3 s per repetition. The frequency of high‐level strain (ie, ≥9%) continuously decreased in INT, while tending to increase in CON since tendon force increased in both (p < 0.001), yet tendon stiffness only in INT (p = 0.004). In CON, tendon strain was inversely associated with tendon peak spatial frequency at all time points (p < 0.05), indicating impairments of tendon micromorphological integrity with higher strain, but not at M2 and M3 in INT. Descriptively, the fraction of asymptomatic athletes at baseline was similar in both groups (~70%) and increased to 100% in M3 in INT, while remaining unchanged in CON. We suggest that functional high‐load tendon exercises could reduce the prevalence of high‐level patellar tendon strain and associated impairments of its micromorphology in adolescent athletes, providing new opportunities for tendinopathy prevention.
Research on the Flow Resistance Coefficient of a Multihole, Secondary Pressure-Reducing Sleeve Valve
Authors: Xu Dong-tao , Ge Chang-rong , Meng Xiang-rui 
Published: April 2021

Abstract
When fluid flows through a regulating valve, static pressure changes due to the change of fluid area. If the static pressure is lower than saturated vapor pressure, cavitations erosion, and flash vaporization will occur. Cavitations and flash vaporization are the main causes of the vibration and noise of the valve. A multihole sleeve valve with a secondary pressure-reducing function is presented in this paper, two pressure-reducing components are assembled to the valve. The high-pressure difference in the valve can be broken down into several small pressure differences. But the pressure-reducing components have a significant influence on the flow resistance coefficient of the valve. So, the common flow resistance coefficient is no longer suitable for designing the multihole, secondary pressure-reducing sleeve valve. In this paper, the relationship of the flow rate, the flow area, and flow resistance coefficient of the valve is established. The flow area and the flow rate of the valve at the different openings are obtained using simulation software. They are substituted into the relationship equation, in this way, the flow resistance coefficients of the valve can be obtained. In order to verify the reliability of the simulation, a parallel flow test equipment for the valve is established, and the flow rate at different opening are detected. The test result shows that the valve designed by simulation conforms to the specified flow characteristics. By the revision of the flow resistance coefficient, the throttling holes of the valve can be designed conveniently and accurately. The designed valve has good flow regulating ability and can solve the problem of cavitations erosion and flash vaporization.
Vortex Dynamics and Instability Mechanisms in a Radially Lobed Nozzle
Authors: Sekaran Aarthi , Amini Noushin 
Published: April 2021

AbstractThe application of radially lobed nozzles has seen renewed challenges in the recent past with their roles in combustion chambers and passive flow control. The free jet flow from such nozzles has been studied for different flow conditions and compared to jets from round nozzles, verifying their improved mixing abilities. The precise mixing mechanisms of these nozzles are, however, not entirely understood and yet to be analyzed for typical jet parameters and excitation modes. This study carries out three-dimensional large eddy simulations (LESs) of the flow from a tubular radially lobed nozzle to identify instability mechanisms and vortex dynamics that lead to enhanced mixing. The flow is studied at two Reynolds numbers of around 6000 and 75,000, based on the effective jet diameter. The low Reynolds number jet is compared to that from a round nozzle and experimental data to demonstrate changes in mixing mechanisms. The present simulations confirmed the presence of Kelvin–Helmholtz (K–H)-like modes and their evolution. The analysis also confirms the evolution of three distinct types of structures—the large-scale streamwise modes at the lobe crests, corresponding K–H structures at the troughs, and an additional set of structures generated from the lobe walls. The higher Reynolds number simulations indicate changes in the mechanics with a subdued role of the lobe walls.
A Taxonomy of Mechanical Design
Authors: Ullman D. G. 
Published: April 2021

Abstract
Over the last few years there has been a flurry of activity in the study of the mechanical design process. This has been fostered by a perceived lack of efficiency and resulting quality in U.S. product designs compared with those of the Japanese and the Europeans. Research activity is broad and has varied over areas as diverse as: the development of computer codes using AI techniques to solve specific problems requiring expertise in a narrow domain; the commercialization of general, parametric design tools; and the modeling of the human cognitive design process. As results have been published, it has become obvious that the term “design” means different things to different researchers. The field is mature enough to allow techniques and results to be classified, compared and contrasted. However, this is difficult because there is no agreed upon description of the types of design and design studies. In other words, there is a need for a taxonomy to characterize the mechanical design process and the research on it.
Partitioning and Guided Search: A Generalized Approach to Problem Solving in Preliminary Design
Authors: Srinivasan S. , Allen R. H. 
Published: April 2021

Abstract
We report on using problem partitioning and constraint-guided search as a generalized approach to problem-solving in preliminary design. Specifically, a generic design template has been created as a tool to structure information to facilitate problem-solving in three different domains. The approach has been tested through the implementation of knowledge-based systems for the preliminary design of mechanical springs, composite sublaminates and expert systems. Information in each implementation has been partitioned as hierarchical levels of abstraction related through constraints. Function identifies the top level design goals to reduce the search involved for feasible solutions. Goal-directed search, driven by the design application and top-down refinement, reduces the number of possible alternatives. The commonalities extant in the domains have been represented as design goals at three levels of abstraction in the design template. Similar frame-based knowledge representations with inheritance hierarchies and mixed reasoning have been developed for the KEE™-based implementations in each domain. Distinctions among the domains have been modelled as low level slots in the frame hierarchy.
Parametric studies in the domains of mechanical springs, composite sublaminates and expert systems indicate that the minimum number of decision levels required to characterize the preliminary design process in these domains is three; fewer levels would be insufficient to fundamentally characterize the designs. Further, it is observed hierarchical structuring of design information facilitates capturing the interactions among design variables at different levels of abstraction. By using the template representation and reasoning in other divisible domains, the effectiveness of our approach can be further investigated.
Geometric Feature Recognition by Object Decomposition
Authors: Karra C. , Phelps T. A. 
Published: April 2021

Abstract
Design engineers have traditionally have had inadequate manufacturing information. One method of getting that information to them is through its inclusion in computer-based design tools such as geometric solid modelling programs. Analysis of geometry requires methods such as feature recognition. A new approach to feature recognition has been developed which recognizes features by taking apart the original solid object into prismatic primitives. This approach already covers a very large portion of what is currently manufactured. The expected applications of this approach include automatic manufacturability analysis, design for assembly, process planning, etc.
A Simple Practical Criterion to Guarantee Second Order Smoothness of Blend Surfaces
Authors: Pegna J. , Wolter F.-E. 
Published: April 2021

Abstract
Computer Aided Geometric Design of surfaces sometimes presents problems that were not envisioned by mathematicians in differential geometry. This paper presents mathematical results that pertain to the design of second order smooth blending surfaces. Second order smoothness normally requires that normal curvatures agree along all tangent directions at all points of the common boundary of two patches, called the linkage curve. The Linkage Curve Theorem proved here shows that, for the blend to be second order smooth when it is already first order smooth, it is sufficient that normal curvatures agree in one direction other than the tangent to a first order continuous linkage curve. This result is significant for it substantiates earlier works in computer aided geometric design. It also offers simple practical means of generating second order blends for it reduces the dimensionality of the problem to that of curve fairing, and is well adapted to a formulation of the blend surface using sweeps. From a theoretical viewpoint, it is remarkable that one can generate second order smooth blends with the assumption that the linkage curve is only first order smooth. This property may be helpful to the designer since linkage curves can be constructed from low order piecewise continuous curves.
The Modeling of Bevel Gears Using the Exact Spherical Involute
Authors: Al-Daccak M. J. , Angeles J. 
Published: April 2021

Abstract
The solid modeling of bevel gears has been recognized as a major design challenge. Various approaches have been proposed to approximate the theoretical involute-generated contact surface of bevel gears. As a means to accurately represent contact surfaces of these gears, the exact spherical involute is introduced here. The solid models of straight and spiral bevel gears are obtained by applying simple sweeping techniques to their tooth profiles which are described by the exact spherical involute. Furthermore, the volumetric properties of the modeled bevel gears are readily computed from their piecewise-linear approximation.
The Evaluation of Moments of Regions With Piecewise-Linearly Approximated Boundaries via Line Integration
Authors: Angeles J. , Al-Daccak M. J. 
Published: April 2021

Abstract
The subject of this paper is the computation of the first three moments of bounded regions imbedded in the three-dimensional Euclidean space. The method adopted here is based upon a repeated application of Gauss’s Divergence Theorem to reduce the computation of the said moments — volume, vector first moment and inertia tensor — to line integration. Explicit, readily implementable formulae are developed to evaluate the said moments for arbitrary solids, given their piecewise-linearly approximated boundary. An example is included that illustrates the applicability of the formulae.
Expert System Built on a Chip
Authors: Lu P. , Siddall J. N. , Verhaeghe J. 
Published: April 2021

Abstract
The paper describes an exploration of the possibility of embedding the rules of an expert system directly onto a commercial programmable logic array microchip. The rules are first converted to Boolean form and reduced to minimal form. An interface was developed for using the chip with an IBM PC clone for processing inputs and outputs. No control system (inference engine) is required; and the execution of an application is equivalent to parallel processing. The inputs are transferred to the input pins of the logic array chip in successive bytes of data, and the conclusions then immediately appear at the output pins. The success of the approach was verified with two small examples.
We have also extended the concept to develop an original algorithm for minimizing the number of required inputs for a specific application.
This approach to designing expert systems should have an important potential for control systems where speed is important, and also in other systems where size and speed are important performance characteristics.
Optimal and Conforming Motion of a Point in a Constrained Plane
Authors: Ahrikencheikh C. , Seireg A. A. , Ravani B. 
Published: April 2021

Abstract
This paper deals with automatic generation of motion of a point under both geometric and non-geometric constraints. Optimal point paths are generated which are not only free of collisions with polygonal obstacles representing geometric constraints but also conform to non-geometric constraints such as speed of the motion, a maximum allowable change in the velocity vector and a minimum clearance from the obstacle boundaries. The concept of passage networks and conforming paths on the network are introduced. These are used to provide a new representation of the free space as well as a motion generation algorithm with a computational time complexity of only O(n3.log(n)), where n designates the total number of obstacle vertices. The algorithm finds the shortest or fastest (curved) path that also conforms with preset constraints on the motion of the point. The point paths generated are proved to be optimal while conforming to the constraints.
Optimality and Constrained Derivatives in Two-Level Design Optimization
Authors: Azarm S. , Li W.-C. 
Published: April 2021

Abstract
The objective of this paper is twofold. First, an optimality test is presented to show that the optimality conditions for a two-level design optimization problem before and after its decomposition are the same. Second, based on identification of active constraints and exploitation of problem structure, a simple approach for calculating the gradient of a “second-level” problem is presented. This gradient is an important piece of information which is needed for solution of two-level design optimization problems. Three examples are given to demonstrate applications of the approach.
The Method of Alternate Formulations Applied to Optimization Problems With Functionally Dependent State Equations
Authors: Hammond C. R. , Johnson G. E. 
Published: April 2021

Abstract
The Method of Alternate Formulations (MAF) is a non-numerical approach to constrained optimal design. MAF requires that the problem statement be transformed into an objective function, a set of equality-constraints (i.e. state equations), and a set of upper and lower bounds on the variables. In this format, the design vector can be partitioned into decision variable and state variable components. This is the same format as used in the solution of such problems by the generalized reduced gradient method.
The fact that there are usually several ways to effect the partition of the design vector gives rise to the existence of alternate formulations. Each alternate formulation contains all of the information about the physical system — and the constrained optima are invariant under the transformation from form to form. Yet all other mathematical properties (e.g., convexity, linearity, scaling, etc.) can change.
In this paper, we consider the special case when the state equations are functionally dependent, hence some of the expected constraint intersections do not exist. Several examples are used to demonstrate the concept of functional dependence and to show how functional dependence affects the search for the solution.
Numerical Optimization of Rotor-Bearing Systems
Authors: Sadler J. P. , Rouch K. E. , Rani A. S. 
Published: April 2021

Abstract
Nonlinear programming techniques are combined with a finite element program for dynamic analysis of rotor-bearing systems. The resulting program provides the means for obtaining optimal designs for improved dynamic performance of a rotor through the automated selection of various design parameters of the rotor-bearing system. Both constrained and unconstrained optimizations are considered. Illustrative examples are presented for the case of optimum placement of critical speeds.