bluuebunny/crossref_metadata_2025 huggingface dataset:
An Inverse Force Analysis of a Planar Two-Spring System
Authors: Pigoski Thomas M. , Duffy Joseph
Published: March 2021

A closed-form inverse force analysis was performed on a planar two-spring system. The two springs were grounded to pivots at one end and attached to a common pivot at the other. A known force was applied to the common pivot of the system, and it was required to determine all of the assembly configurations. By variable elimination, a sixth degree polynomial in the resultant length of one spring was derived, and from this, six real solutions of the point of application of force were obtained. Following this, the applied force was incremented along a line and the six paths of the moving pivot were tracked starting from the zero-load configurations. An analysis of these results showed stability phenomena indicating the workspace of this system contained regions of negative spring stiffness and points of catastrophe.
Genetic Design of Dynamically Optimal Four-Bar Linkages
Authors: Porter Brian , Mohamed Samir S. , Sangolola Bamidele A.
Published: March 2021

It Is shown in this paper that, once the problem of designing dynamically optimal mechanisms is formulated as a constrained minimisation problem, genetic algorithms provide a procedure for solving this design problem which is very powerful but also very simple. These general results are illustrated by the genetic optimisation of a particular four-bar linkage that was previously optimised non-genetlcally. However, It is pointed out that the genetic design methodology described in this paper can in principle be used to minimise any desired combination of forces and couples in any mechanism.
Analytical Synthesis of Adjustable Dyads and Triads for Designing Adjustable Mechanisms
Authors: Chuenchom Thatchai , Kota Sridhar
Published: March 2021

The paper presents generalized analytical methods for designing adjustable mechanisms based on synthesis of adjustable dyads and triads. The synthesis methods presented here are extensions of the well-known Burmester precison point theory. The adjustable dyad (and traid) synthesis method enables one to design mechanisms for multiple sets of precision points (multiple tasks). Two or more adjustable dyads (or triads) assembled together to form four-bar or geared five bar mechanisms that meet the requirements of multiple tasks. The method generates all adjustable -dyad and -triad solutions for given sets of precision points. Synthesis formulations and the solution spaces are described in detail. Design examples illustrating the synthesis methods are also presented.
A New Method and Automatic Generation for Kinematic Analysis of Complex Planar Mechanisms Based on the Ordered Single-Opened-Chains
Authors: Shen Hui-Ping , Yang Ting-Li
Published: March 2021

This work presents a new method for kinematic analysis of planar complex mechanisms, i. e, the ordered single-opened-chains method. This method makes use of the ordered single-opened chains (in short, SOC.) along with the properities of SOC, and the network constraints relationship between SOC. By this method, any planar complex mechanism ran be automatically decomposed into a series of the ordered single-opened chains and the optimal structural decomposition route(s) can be automatically selected for kinematic analysis. The kinematic analysis equations with fewest unknown variables can be automatically generated and easily solved. Perhaps, the most attractive features of this method are its high automation and convergence in computer implementations.

This work firstly describes the principle of the ordered SOC method and then introduces the computer automatic generation of this method along with the application to two complex linkages.

The method developed can be easily extended to the kinemetic analysis of the spatial mechanisms.
The Dynamics of Rigid Objects on Shaking Belt Conveyors for Self-Orientation
Authors: Khader Khaled M. , Angeles Jorge , Moustafa Mahmoud A. , El-Shakery Sabry A. , Abou-Elnasr Raafat A.
Published: March 2021

Flexible manufacturing systems with belt conveyors that transport workpieces in batches to be picked up by a robot motivated this work. In such systems, workpieces are discharged onto a belt conveyor with arbitrary orientations and then transported to another station where a robot picks them up. In order to enhance the reliability of the robot and simplify its operation, the workpieces should be presented with the same orientation, which is the task of the conveyors studied here.
A New Method and Automatic Generation for Dynamic Analysis of Complex Planar Mechanisms Based on the Ordered Single-Opened-Chains
Authors: Zhang Jian-Qing , Yang Ting-Li
Published: March 2021

This work presents a new method for kinetostatic analysis and dynamic analysis of complex planar mechanisms, i.e. the ordered single-opened-chains method. This method makes use of the ordered single-opened chains (in short, SOC,) along with the properties of SOC, and the network constraints relationship between SOC,. By this method, any planar complex mechanism can be automatically decomposed into a series of the ordered single-opened chains and the optimal structural decomposition route (s) can be automatically selected for dynamic analysis, the paper present the dynamic equation which can be used to solve both the kinetostatic problem and the general dynamic problem. The main advantage of the proposed approach is the possibility to reduce the number of equations to be solved simultaneously to the minimum, and its high automation as well. The other advantage is the simplification of the determination of the coefficients in the equations, and thus it maybe result in a much less time-consuming algorthem. The proposed approach is illustrated with three examples.

The presented method can be easily extended to the dynamic analysis of spatial mechanisms.
The Development of Flex-Gears for the Conduction of Electricity Across a Continuously Rotating Joint
Authors: Peritt Jonathan M. , Tsai Lung-Wen , Vranish John M.
Published: March 2021

The transfer of electricity across a continuously rotating joint is especially important in robot joints and brush-type motors. In this paper, the shortfalls of present technologies, such as electric brushes, arc discussed. Flex-gears are presented as an alternative method of transferring electricity across a continuously rotating joint. A new type of gear, called a pitch-rolling-gear, is developed from involute gear technology for use as a flex-gear. Finally, the design of planetary flex-gear devices using pitch-rolling-gears is presented.
Using Geared Mechanisms to Increase the Thermal Efficiency of Conventional IC-Engines
Authors: Rocheleau David N.
Published: March 2021

Two different geared mechanisms are examined as an alternative to the conventional crank-slider mechanism that is used for the 4-stroke internal combustion engine. The purpose of these geared mechanisms is to provide variable-stroke length and constant-volume combustion. The variable-stroke length feature gives a power stroke which is two to three times longer than the compression stroke, which allows additional work to be extracted as the gas expands to nearly atmospheric pressure. The constant-volume combustion feature prevents the dissipation of compressive work during ignition. The combination of these two features leads to theoretical thermal efficiency gains of up to 45% over the standard fixed-stroke length Otto-cycle internal combustion engine.
Modeling Continuum Multibody Systems Using the Finite Element Method and Element Convected Frames
Authors: Wasfy Tamer M.
Published: March 2021

A new method for predicting the dynamic response of flexible multibody systems is developed. The method can account for large rigid-body motion and large deflections. The method is based on the Finite Element Method and the use of a new type of element convected frames. Continuum type elements are used to model the multibody system. The motion of the “nodes” is referred to a global inertial reference frame. D’Alembert principle is used to derive the system’s equations of motion, by invoking the equilibrium, at the nodes, of inertia forces, structural (internal) forces and externally applied forces. Structural forces on a node are calculated from the state of deformation of the elements surrounding that node. Each element has a convected frame which translates and rotates with it. This frame is used to extract the flexible deformation of the element from the total element motion. The orientation of a convected frame is found using the deformation gradient tensor and the Polar decomposition theorem. The equations of motion are solved along with constraint equations using a direct implicit iterative integration scheme. A numerical example is solved to demonstrate some of the features of the new method.
Numerical Solution and Experiment Researches on Flexible Multibody Dynamics
Authors: Hongzhao Liu , Weiqing Cao
Published: March 2021

In this paper, a numerical solution method and an experiment research on flexible multibody dynamics are presented. The augment method is employed to transfer the differential-algebraic equations into differential equations, both generalized coordinates and lagrange multipliers are treated as unknowns, and the second-order self-correcting algorithm is introduced to guarantee convergence. The lagrange multipliers are eliminated analytically, and the half implicit Runge-Kutta formula is taken for solving the differential equations. The whole procedure is developed into a FORTRAN program. An elastic linkage test bed and a measuring system are made for verification. The computing results are in agreement with the measuring data.
A General Theory for Complete Balancing of Shaking Force and Shaking Moment of Spatial Linkages Using Counterweights and Inertia-Counterweights
Authors: Yang Ting-Li , Zhang Ming , Zhang Jian-Qin
Published: March 2021

The links of a spatial linkage with v independent loops can be divided into two parts — a set of v chord-links and a tree-system. Add a suitable counterweight to each chord-link for satisfying the certain conditions, under which, the v chord-links can be completely shaking force-moment-balanced by the counterweights and inertia-counterweights attached to the tree-system of the linkage; The conditions for complete balance of shaking force and shaking moment of the tree system can be written directly without extracting them from the kinematic equation of the linkage; A formula which define the minimum number of inertia-counterweights needed for a complete shaking-moment-balance and the criteria for selecting the optimum chord-link set have been presented. Two examples (a Bennett linkage and a spherical six-bar linkage) are provided.
Linking a CAD System to an Expert System: A Step Towards a Knowledge-Based Design System for Mechanisms
Authors: Funk Wolfram , Kinzinger Rudolf
Published: March 2021

The design process can be divided into different phases. The best order in which the designer should execute these steps remains difficult to predict. In principle, conventional computer programs can only be applied to problems for which algorithms are available. Therefore, in many fields the design process did not allow computer support. The technology of knowledge-based systems has led to new perspectives. However, knowledge-based systems can only be utilized if the well-established design aid, CAD system, is integrated into the concept of knowledge-based computer support. Conceptual considerations and new approaches to linking a CAD system to an expert system, which assists the designer in solving kinematic problems, especially in the conceptual phase, are presented.
Dimensional Synthesis of Compliant Constant-Force Slider Mechanisms
Authors: Howell Larry L. , Midha Ashok , Murphy Morgan D.
Published: March 2021

Constant-force mechanisms produce a constant output force for a range of input displacements. Such mechanisms are important in applications with a varying displacement but a constant resultant force required. Constant-force mechanism designs have been limited to rigid-link mechanisms, but the design of compliant, or flexible link, constant force mechanisms could increase the number of applications by taking advantage of the unique characteristics of compliant mechanisms. Murphy (1993) developed type-synthesis theories for compliant mechanisms and applied them to generate possible configurations for compliant constant-force slider mechanisms. This paper concentrates on the dimensional synthesis of several of the resulting topologies. Optimization and the pseudo-rigid-body-model concept are employed in the design procedure. An example application as an electrical connection for use in electronic chip carriers is also illustrated.
Emulating Micro-Gravity in Laboratory Studies of Space Robotics
Authors: Corrigan Thomas R. J. , Dubowsky Steven
Published: March 2021

Experimentally evaluating micro-gravity control and planning algorithms for space robotic systems on earth is difficult because gravity masks the more subtle dynamic forces which dominate in space. Previous experimental test beds for micro-gravity have been largely restricted to planar motion, or have other limitations. Recently developed is a fully spatial system called the VES which overcomes many of these problems. However, compensating for the effects of gravity with the VES is a challenge. Here, two methods of gravity compensation are presented which allow fully spatial emulation of the micro-gravity interaction between a space manipulator and its supporting structure or spacecraft. Experimental results show the effectiveness of the methods.
Assembly Product and Cooperating Multi-Robot Cell Design Based on Constraints Interaction Analysis
Authors: Rajan Venkat N.
Published: March 2021

Cooperating multi-robot cells are highly flexible, reliable, and reconfigurable. Flexibility is obtained by the enhanced task processing capability due to cooperation, reliability is obtained by the ability to substitute failed robots by cooperating robot sets, and re-configurability is obtained by the ease with which the cell can be changed from one assembled product to another. These features can only be exploited by the proper design and planning of the cell.

Integrated assembly and task planning is essential to generate optimal plans by the application of both assembly and cell constraints simultaneously. In prior research the integrated Cooperation Requirement Planning (CRP) methodology was presented. In this paper the CRP methodology is used to show the effect of interactions between fixed assembly constraints and variable robot constraints on the design of assembly products and multi-robot cells. It is shown that the planning methodology can be used to exploit the cell capability with minimal redesign. In cases where this is not possible, the planning results indicate potential modifications to the multi-robot cell and/or the assembled product.
Optimal Robotic Assembly Planning Using Dijkstra’s Algorithm
Authors: Anand Sam , Sabri Mohamed
Published: March 2021

Robots play an important role in the modern factory and are used in a manufacturing cell for several functions such as assembly, material handling, robotic welding, etc. One of the principal problems faced by robots while performing their tasks is the presence of obstacles such as fixtures, tools, and objects in the robot workspace. Such objects could result in a collision with one of the arms of the robots. Fast collision-free motion planning algorithms are therefore necessary for robotic manipulators to operate in a wide variety of changing environments. The configuration space approach is one of the widely used methods for collision-free robotic path planning. This paper presents a novel graph-based method of searching the configuration space for a collision-free path in a robotic assembly operation. Dijkstra’s graph search algorithm is used for optimizing the joint displacements of the robot while performing the assembly task. The methodology is illustrated using a simple robotic assembly planning task.
Passive Assembly of Non-Axisymmetric Rigid Parts
Authors: Sturges R. H. , Laowattana Schitt
Published: March 2021

This paper addresses automatic assembly with passive rather than active compliant devices. Previous work has shown that in an ideal manufacturing environment three assembly primitives (prismatic insertions, threaded fits and general path insertions) exhibit a high level of difficulty. None of these are reliably assemblable under sensor-based force control or with an ordinary remote center compliance (RCC) device. In this paper, we extend the science of part mating and apply dexterity theory to synthesize a passive assembly device for precision fits of three-dimensional prismatic parts. This Spatial Remote Center Compliance (SRCC) obviates sensor-based and force control approaches to precision assembly of non-axisymmetric parts.
Collaborative Engineering Based on Knowledge Sharing Agreements
Authors: Olsen Gregory R. , Cutkosky Mark , Tenenbaum Jay M. , Gruber Thomas R.
Published: March 2021

The design of products by multi-disciplinary groups is a knowledge intensive activity. Collaborators must be able to exchange information and share some common understanding of the information’s content. The hope, however, that a centralized standards effort will lead to integrated tools spanning the needs of engineering collaborators is misplaced. Standards cannot satisfy the information sharing needs of collaborators, because these needs cannot be standardized.

This paper discusses the design and use of a shared representation of knowledge (language and vocabulary) to facilitate communication among specialists and their tools. The paper advances the opinion that collaborators need the ability to establish and customize knowledge sharing agreements (i.e. mutually agreed upon terminology and definitions) that are usable by people and their machines. The paper describes a formal approach to representing engineering knowledge, describes its role in a computational framework that integrates a heterogeneous mix of software tools, and discusses its relationship to current and emerging data exchange standards.

This work is supported by ARPA contract DAAA 15-91-C0104 as part of the SHADE project. (CDR TR# 19940912)
An Assembly Constraint Model for Parameterized Mechanical Systems
Authors: Wang J. H. , Wu J. K.
Published: March 2021

This paper (1) introduces Natural Assembly Relationships (NARs) to model assembly constraints between parts and (2) analyzes the constraint relationships that are defined using NARs for parameterized mechanical assemblies. The NARs are expressed as first order predicates using primitive features as arguments, such as planar and cylindrical surfaces. The concept of Basic Parameters Set is introduced as the design parameters in CAD systems, which, together with a set of form feature constraint relationships, maintains maximal consistency with original design meanings. Based on NARs, part parameters, and primitive features, design parameter chains can be constructed for closed loop assemblies. From these chains, constraint equations can be derived, which are the basis for change propagation and information management for mechanical system design.
An Architecture for Handling Manufacturing Exceptions Based on Information Integration
Authors: Wang Ching-Yang , Fulton Robert E.
Published: March 2021

Currently, most efforts to characterize manufacturing processes are based on the normal process assumption and pay little attention to exceptions. An exception is either a rare or an unexpected event which interrupts the normal manufacturing processes. There are potential exceptions in all stages of manufacturing processes. Exceptions like resource mismanagement (at the management decisions level), process out-of-control (at the technical strategies level) and product quality deterioration (at the operational plans level) can and do occur. These exceptions can have detrimental effects on quality, reliability and productivity. Little is known about managing unexpected events in manufacturing information integration.

A conceptual exception model for handling manufacturing exceptions is proposed. The architecture of the exception model includes the views of levels impacted, process flow, inference network and decision propagation, information relations, math/logic formalism, feedback control, user action and avoidance knowledge base. These multiple views are designed to aid in understanding the exceptional problems, in characterizing the information requirements and in building an information system.

An information system for an optical fiber manufacturing process was implemented as a case study of the model. The case study has been implemented in the Smalltalk environment. The developing procedure of the information system serves to illustrate the concepts of the exception model. This research is expected to benefit persons, such as system integrators, who need to build exception management information systems. Such an information system provides a platform for users to execute exception management capabilities such as recovery plans to aid in coping with exceptions and the impact and decision propagation regarding exceptions.
Integrating Human Knowledge Into the Product Development Process
Authors: Tegel Oliver
Published: March 2021

Specialists are often needed for solving the demanding tasks that arise during the development of today’s advanced products. During product development, assistance is required from other departments such as manufacturing, operations scheduling etc. Even the vendors and customers should be integrated into the product development process to guarantee the product developed will be accepted in the market. Information from different people in different forms must be collected aiming at a final good design. A problem occuring during product development is, how to know which people to contact for what kind of information. An approach for solving this problem is presented in this paper.
Progression of myopia in children and teenagers: a nationwide longitudinal study
Authors: Tricard Dorian , Marillet Simon , Ingrand Pierre , Bullimore Mark A , Bourne Rupert R A , Leveziel Nicolas
Published: March 2021

Background

Data on myopia prevalence and progression in European children are sparse. The aim of this work was to evaluate the progression of myopia in children and teenagers in a large prospective study.

Methods

A prospective study involving a nationwide cohort. Myopia was defined as a spherical equivalent (SE) of ≤ –0.50 diopters (D). Data on refractive error, gender and age were collected in 696 optical centres in France between 2013 and 2019, including 136 333 children (4–17 years old) in the analysis.

Progression of myopia was assessed between the first visit and the last visit over up to 6.5 years.

Results

Mean age was 11.3±3.8 years (55.0% of female). The proportion of children progressing more than –0.50 D per year was higher in age groups 7–9 years and 10–12 years and in children with SE ≤ –4.00 D at first visit, representing 33.1%, 29.4% and 30.0% of these groups, respectively. In multivariate analysis, progression during the first 11–24 months was higher in the 7–9 and 10–12 age groups (–0.43 D and –0.42 D, respectively), for higher SE at baseline (at least –0.33 D for SE ≤ –1 D) and for girls (–0.35 D).

Conclusion

This is the first French epidemiological study to investigate myopia progression in a large-scale cohort of children. Sex, age groups and myopia severity are associated with differing rates of progression.
NOTCH3 variants are more common than expected in the general population and associated with stroke and vascular dementia: an analysis of 200 000 participants
Authors: Cho Bernard P H , Nannoni Stefania , Harshfield Eric L , Tozer Daniel , Gräf Stefan , Bell Steven , Markus Hugh S
Published: March 2021

Background

Cysteine-altering NOTCH3 variants identical to those causing the rare monogenic form of stroke, CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy), have been reported more common than expected in the general population, but their clinical significance and contribution to stroke and dementia risk in the community remain unclear.

Methods

Cysteine-altering NOTCH3 variants were identified in UK Biobank whole-exome sequencing data (N=200 632). Frequency of stroke, vascular dementia and other clinical features of CADASIL, and MRI white matter hyperintensity volume were compared between variant carriers and non-carriers. MRIs from those with variants were visually rated, each matched with three controls.

Results

Of 200 632 participants with exome sequencing data available, 443 (~1 in 450) carried 67 different cysteine-altering NOTCH3 variants. After adjustment for various covariates, NOTCH3 variant carriers had increased risk of stroke (OR: 2.33, p=0.0004) and vascular dementia (OR: 5.00, p=0.007), and increased white matter hyperintensity volume (standardised difference: 0.52, p<0.001) and white matter ultrastructural damage on diffusion MRI (standardised difference: 0.72, p<0.001). On visual analysis of MRIs from 47 carriers and 148 matched controls, variants were associated with presence of lacunes (OR: 5.97, p<0.001) and cerebral microbleeds (OR: 4.38, p<0.001). White matter hyperintensity prevalence was most increased in the anterior temporal lobes (OR: 7.65, p<0.001) and external capsule (OR: 13.32, p<0.001).

Conclusions

Cysteine-changing NOTCH3 variants are more common in the general population than expected from CADASIL prevalence and are risk factors for apparently ‘sporadic’ stroke and vascular dementia. They are associated with MRI changes of small vessel disease, in a distribution similar to that seen in CADASIL.
Trends and outcomes of ruptured ovarian cysts
Authors: Lim Wei How , Woods Nikki , Lamaro Vincent P
Published: March 2021

Background

Ruptured ovarian cysts are common gynaecological presentation to health institutions with abdominal pain. While this phenomenon is generally self-limiting, surgery may be necessary in cases of haemodynamic compromise or association with torsion. The aim of this audit is to identify the trend of hospital presentations, as well as the review the management of modern gynaecology practice.

Methods

A retrospective audit of all women who presented to the emergency department with an imaging diagnosis of ruptured ovarian cysts was conducted over a 5-year period at St Vincent's Hospital, Sydney.

Results

During the study period, 408 women were identified. There was a trend towards conservative management, as observed in 84.7% of women, while the remaining 15.4% underwent surgery. Haemorrhagic or ruptured corpus luteum was the most common diagnoses. As expected, women who had surgical intervention were more likely to have larger cysts (20 vs 50%; p<0.05), and larger free fluid findings on imaging (1.4 vs 23.8%; p<0.05) compared with those managed conservatively. There were no statistically significant differences in location of ovarian cysts (right or left) or antecedent to hospital presentation (vaginal intercourse or trauma).

Conclusion

Ruptured ovarian cysts of both functional and non-functional types remained a common clinical presentation of acute pain for women to the emergency department. Majority of women were managed conservatively in our cohort, and indications for surgery were large ovarian cysts and large free fluid seen on imaging findings. Surgery was largely feasible with minimal complications.
The potential environmental risks associated with the development of rare earth element production in Canada
Authors: Yin Xiangbo , Martineau Christine , Demers Isabelle , Basiliko Nathan , Fenton Nicole J.
Published: March 2021

The development of rare earth element (REE) production in Canada could generate significant economic benefits but also poses serious potential risks to the environment. Rare earth elements have been widely used in modern life and industries and are even indispensable in some crucial advanced technologies (e.g., permanent magnets). Increasing demand and the current United States – China trade tensions provide a commercial economic development opportunity for Canada, which has rich resources of REEs, to develop its own sector. However, environmental and health issues caused by REE production are challenges that Canada has to face given that significant environmental impacts have been reported elsewhere (e.g., China). Little literature is available on the potential environmental risks associated with the development of REE production in Canada. It is important to know what environmental issues, particularly those generated by REEs themselves, may happen in Canada in the future. Therefore, three major aspects are evaluated and summarized from multidisciplinary perspectives in this paper: (1) a general conceptual model of the transport of REEs as a group in the environment is established; (2) toxicity levels, biochemical mechanisms, and physiological effects of REEs on different organisms are reviewed, and case-studies from existing REE mining areas are briefly highlighted; and (3) considering specific environmental condition and risk factors, environmental risks that Canada may face in future REE developments are identified and discussed. This review concludes with macro-identification of potential environmental risks associated with the development of REE production in Canada considering both human and ecological health. We note that ingestion, inhalation, and dermal exposure for workers and surrounding residents (including potentially Indigenous communities) and subarctic and arctic climate conditions could increase the risks to human and ecological health in future REE production development in Canada. Finally, future research directions are proposed that could be applied to both Canadian and other geographical contexts.
A generalized anisotropic model for super dense stars
Authors: Estevez-Delgado Joaquin , Estevez-Delgado Gabino , Maya Noel Enrique Rodríguez , Peña José Martínez , Murguía Aurelio Tamez
Published: March 2021

A static anisotropic relativistic fluid sphere model with regular geometry and finite hydrostatic functions is presented. In the interior of the sphere, the density, radial pressure and tangential pressure are positives, monotonically decreasing with increasing radius and the radial pressure vanishes at the surface of the matter distribution and is joined continuously to the exterior Schwarzschild’s solution at this surface. The speeds of the radial and tangential sound are positive and lower than the speed of light, that is, the causal condition is not violated, and also the behavior of these guarantees that the model is potentially stable. Furthermore, the range of the compactness ratio is characteristic of compact stars and it is shown that the effect of the anisotropy generates that the speed of the radial sound can behave as a function monotonically increasing or monotonically decreasing.
Upper triangle free detour number of a graph
Authors: Sethu Ramalingam S. , Athisayanathan S.
Published: March 2021

For any two vertices [Formula: see text] and [Formula: see text] in a connected graph [Formula: see text], the [Formula: see text] path [Formula: see text] is called a [Formula: see text] triangle free path if no three vertices of [Formula: see text] induce a triangle. The triangle free detour distance [Formula: see text] is the length of a longest [Formula: see text] triangle free path in [Formula: see text]. A [Formula: see text] path of length [Formula: see text] is called a [Formula: see text] triangle free detour. A set [Formula: see text] is called a triangle free detour set of [Formula: see text] if every vertex of [Formula: see text] lies on a [Formula: see text] triangle free detour joining a pair of vertices of [Formula: see text]. The triangle free detour number [Formula: see text] of [Formula: see text] is the minimum order of its triangle free detour sets and any triangle free detour set of order [Formula: see text] is a triangle free detour basis of [Formula: see text]. A triangle free detour set [Formula: see text] of [Formula: see text] is called a minimal triangle free detour set if no proper subset of [Formula: see text] is a triangle free detour set of [Formula: see text]. The upper triangle free detour number [Formula: see text] of [Formula: see text] is the maximum order of its minimal triangle free detour sets and any minimal triangle free detour set of order [Formula: see text] is an upper triangle free detour basis of [Formula: see text]. We determine bounds for it and characterize graphs which realize these bounds. For any connected graph [Formula: see text] of order [Formula: see text], [Formula: see text] Also, for any four positive integers [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] with [Formula: see text], it is shown that there exists a connected graph [Formula: see text] such that [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text], where [Formula: see text] is the upper detour number, [Formula: see text] is the upper detour monophonic number and [Formula: see text] is the upper geodetic number of a graph [Formula: see text].
Nature of the Cuvier Abyssal Plain crust, offshore NW Australia
Authors: Reeve Matthew T. , Magee Craig , Bastow Ian D. , McDermott Carl , Jackson Christopher A.-L. , Bell Rebecca E. , Prytulak Julie
Published: March 2021

Magnetic stripes have long been assumed to be indicative of oceanic crust. However, continental crust heavily intruded by magma can also record magnetic stripes. We re-evaluate the nature of the Cuvier Abyssal Plain (CAP), offshore NW Australia, which hosts magnetic stripes and has previously been defined as oceanic crust. We show that chemical data from a basalt within the CAP, previously described as an enriched mid-ocean ridge basalt, could equally be interpreted to contain evidence of contamination by continental material. We also recognize seaward-dipping reflector sequences in seismic reflection data across the CAP. Borehole data from overlying sedimentary rocks suggests that these seaward-dipping reflectors were emplaced in a shallow water (<200 m depth) or subaerial environment. Our results indicate that the CAP may not be unambiguous oceanic crust, but may instead consist of a spectrum of heavily intruded continental crust through to fully oceanic crust. If the CAP represents such a continent–ocean transition zone, then the adjacent unambiguous oceanic crust would be located >500 km further offshore NW Australia than currently thought. This would impact plate tectonic reconstructions, as well as heat flow and basin modelling studies. Our work also supports the growing consensus that magnetic stripes cannot, by themselves, be used to determine crustal affinity.

Supplementary material:
Enlarged and uninterpreted versions of the magnetic data and seismic reflection lines are available at
https://doi.org/10.6084/m9.figshare.c.5332172
South-Central Barents Sea Composite Tectono-Sedimentary Element
Authors: Doré A. G. , Dahlgren T. , Flowerdew M. J. , Forthun T. , Hansen J. O. , Henriksen L. B. , Kåsli K. , Rafaelsen B. , Ryseth A. E. , Rønning K. , Similox-Tohon D. , Stoupakova A. , Thießen O.
Published: March 2021

The south-central Barents Sea today comprises a shallow continental shelf with water depths mainly in the 200–400 m range, straddling the Norway–Russia marine boundary. Geologically, it consists of a stable platform (the Bjarmeland Platform) dissected by rifts of probable Late Carboniferous age, with a significant and geologically persistent basement high (the Fedynsky High) in its southeastern part. The rifts are the ENE–WSW-trending Nordkapp Basin, the similarly trending but less clearly demarcated Ottar Basin and the NW–SE Tiddlybanken Basin. The varying rift trends appear to reflect the orogenic grain patchwork of the basement (Caledonide and Timanide), and these basins were infilled with a variable facies assemblage including substantial Carboniferous–Permian halites.

A massive sedimentary influx of fluvio-deltaic to shallow-marine sediments took place in the Triassic, from the east and SE (Urals, Novaya Zemlya and western Siberia) and the south (Baltic Shield), resulting in doming and diapirism in the areas of thickest salt, particularly in the rifts. The succeeding Jurassic, Cretaceous and Cenozoic successions are generally thin, locally thickening in rim synclines and in the NE of the area towards the deep basins flanking Novaya Zemlya. Reactivation of the halokinetic structures took place in the early Cenozoic, probably associated with the development of the NE Atlantic–Arctic Ocean linkage.

Marine source rocks of Triassic and Late Jurassic age are present in the area, along with Carboniferous and Permian source rocks of uncertain effectiveness. Petroleum has been found in Jurassic and Triassic clastic reservoirs, including recent shallow Jurassic oil and gas discoveries. Although none is currently in production, near-future oil development is likely in the Wisting discovery, on the western margin of the area. New exploration, including drilling, has taken place in the east of the area as a result of recent Norwegian and Russian licensing.
BOND
Authors: Ma Qiang , Cao Zhichao , Gong Wei , Zheng Xiaolong
Published: March 2021

In a large-scale wireless sensor network, hundreds and thousands of sensors sample and forward data back to the sink periodically. In two real outdoor deployments GreenOrbs and CitySee, we observe that some bottleneck nodes strongly impact other nodes’ data collection and thus degrade the whole network performance. To figure out the importance of a node in the process of data collection, system manager is required to understand interactive behaviors among the parent and child nodes. So we present a management tool BOND (BOttleneck Node Detector), which explains the concept of
Node Dependence
to characterize how much a node relies on each of its parent nodes, and also models the routing process as a Hidden Markov Model and then uses a machine learning approach to learn the state transition probabilities in this model. Moreover, BOND can predict the network dataflow if some nodes are added or removed to avoid data loss and flow congestion in network redeployment. We implement BOND on real hardware and deploy it in an outdoor network system. The extensive experiments show that
Node Dependence
indeed help to explore the hidden bottleneck nodes in the network, and BOND infers the
Node Dependence
with an average accuracy of more than 85%.
Distrinet
Authors: Di Lena Giuseppe , Tomassilli Andrea , Saucez Damien , Giroire Frédéric , Turletti Thierry , Lac Chidung
Published: March 2021

Networks have become complex systems that combine various concepts, techniques, and technologies. As a consequence, modelling or simulating them now is extremely complicated and researchers massively resort to prototyping techniques. Mininet is the most popular tool when it comes to evaluate SDN propositions. Mininet allows to emulate SDN networks on a single computer but shows its limitations with resource intensive experiments as the emulating host may become overloaded. To tackle this issue, we propose
Distrinet
, a distributed implementation of Mininet over multiple hosts, based on LXD/LXC, Ansible, and VXLAN tunnels. Distrinet uses the same API than Mininet, meaning that it is compatible with Mininet programs. It is generic and can deploy experiments on Linux clusters (e.g., Grid'5000), as well as on the Amazon EC2 cloud platform.
Data Science in Chemical Engineering: Applications to Molecular Science
Authors: Ashraf Chowdhury , Joshi Nisarg , Beck David A.C. , Pfaendtner Jim
Published: March 2021

Chemical engineering is being rapidly transformed by the tools of data science. On the horizon, artificial intelligence (AI) applications will impact a huge swath of our work, ranging from the discovery and design of new molecules to operations and manufacturing and many areas in between. Early adoption of data science, machine learning, and early examples of AI in chemical engineering has been rich with examples of molecular data science—the application tools for molecular discovery and property optimization at the atomic scale. We summarize key advances in this nascent subfield while introducing molecular data science for a broad chemical engineering readership. We introduce the field through the concept of a molecular data science life cycle and discuss relevant aspects of five distinct phases of this process: creation of curated data sets, molecular representations, data-driven property prediction, generation of new molecules, and feasibility and synthesizability considerations.
Effect of Nitrogen Level on Herbage and Seed Yield of Rhodes Grass (Chloris gayana)
Authors: Faji Dida Mulisa , Abebe Lemore Alemeyehu , Ahmed Seid Kedija
Published: March 2021

Nitrogen is the most important macronutrient for forage and food crop production. Currently, cultivable lands in Ethiopia undergo a deficiency of this element. Thus, this study was conducted to find an appropriate rate of nitrogen (N) fertilizer for the better agronomic performance of Chloris gayana Masaba. The experiment was carried out at Assosa Agricultural Research Center. The experiment was conducted using a randomized complete block design with three replications, and the treatments were five levels of nitrogen fertilizer (0, 23, 46, 69, and 92 kg N/ha). The collected data were analyzed using the general linear model procedure of SAS, and the least significance difference was used for mean separation. Plant height at forage harvesting, dry matter yield, leaf to stem ratio, leaf height, number of leaves per plant, number of tillers, and seed yield were significantly (

p
<
0.001

) influenced by the year of planting while nonsignificantly (

p
>
0.05

) by nitrogen fertilizer rate and interaction of planting year and fertilizer rate. The mean leaf to stem ratio was significantly (

p
<
0.001

) higher in 2017 and 2018 than in the 2019 planting year. However, forage dry matter yield was significantly (

p
<
0.001

) higher in 2019, followed by 2018 and 2017 planting years. Mean seed yield was significantly (

p
<
0.001

) different among the establishment years and the peak seed yield productivity attained during the third year of harvesting (1st = 2nd < 3rd year of harvesting). Generally, all measured agronomic traits were not significantly responsive to the different fertilizer rates, and in the economic point of view, 0 kg of N/ha is recommended.
Autonomous Last-Mile Delivery Based on the Cooperation of Multiple Heterogeneous Unmanned Ground Vehicles
Authors: Wu Yuzhan , Ding Yuanhao , Ding Susheng , Savaria Yvon , Li Meng
Published: March 2021

With the development of e-commerce, the last-mile delivery has become a significant part of customers’ shopping experience. In this paper, an autonomous last-mile delivery method using multiple unmanned ground vehicles is investigated. Being a smart logistics service, it provides a promising solution to reduce the delivery cost, improve efficiency, and avoid the spread of airborne diseases, such as SARS and COVID-19. By using a cooperation strategy with multiple heterogeneous robots, contactless parcel delivery can be carried out within apartment complexes efficiently. In this paper, the last-mile delivery with heterogeneous UGVs is formulated as an optimization problem aimed at minimizing the maximum makespan to complete all tasks. Then, a heuristic algorithm combining the Floyd’s algorithm and PSO algorithm is proposed for task assignment and path planning. This algorithm is further realized in a distributed scheme, with all robots in a swarm working together to obtain the best task schedule. A good solution with an optimized makespan is achieved by considering the constraints of various robots in terms of speed and payload. Simulations and experiments are carried out and the obtained results confirm the validity and applicability of the developed approaches.
The Topical Tranexamic Acid Have Potential Hazard of Promoting Biofilm Formation of Staphylococcus aureus in Microenvironment of the Prosthetic Joint
Authors: Zhang Feiyang , Dong Wenjun , Wang Fengyan , Yu Jinlong , Jiang Feng , Tang Jin , Qian Yan , Shen Hao
Published: March 2021

Background. Perioperative topical tranexamic acid as antifibrinolytic agent is often used for total joint replacement to reduce bleeding currently. Staphylococcus aureus was the most common isolates from perioperative infection of prosthetic joint. The influence of topical application with tranexamic acid on the incidence of acute prosthetic joint infection of Staphylococcus aureus has not been clarified. Methods. Mouse model of Staphylococcus aureus knee prosthesis infection was constructed. Tranexamic acid was intra‐articular injected during the perioperative period. CFU counting from tissue and implant sample was evaluated 3 days and 7 days after inoculating of Staphylococcus aureus. Bacterial growth curve, biofilm formation, aggregation, and plasmin inhibition of Staphylococcus aureus were tested with tranexamic acid added to the synovial culture medium. Results. There were no significant differences of CFU counting from tissue and implant samples in knee prosthesis infection after a single local injection of tranexamic acid at the postoperative 3 or 7 days. The amount of bacterial colonization on the surface of implant increased after 3 days’ continuous local injection of tranexamic acid. Tranexamic acid has no effect on bacterial growth at the concentration (10 mg/ml) of clinical application, but it can inhibit bacterial aggregation and mildly inhibit biofilm formation. Plasmin can significantly inhibit biofilm formation which can be revised by adding tranexamic acid. Conclusion. Although continuous local injection of tranexamic acid can promote the biofilm formation of Staphylococcus aureus on the surface of articular implant, it has clinical safety for using one single local injection of tranexamic acid during the perioperative period.
Infectious Mononucleosis Complicated with Bilateral Peritonsillar Abscess and Splenic Infarction
Authors: Hasibi Mehrdad , Zargaran Mahsa , Asadollahi-Amin Ali
Published: March 2021

Infectious mononucleosis (IM) due to Epstein–Barr virus (EBV) infection is usually self-limited. It presents with fever, pharyngitis, fatigue, and cervical lymph node enlargement. It is common among adolescents and young adults. Although most patients recovered without any sequelae, rare complications have been reported. We described a 28-year-old man with fever, sore throat, dysphagia, and a positive IgM viral capsid Ag (VCA Ag) for EBV infection. He was admitted and received dexamethasone. He developed bilateral peritonsillar abscess (PTA) and splenic infarction, rare complications of acute EBV infection, two days after discharge. Although early reports noted PTA might occur following dexamethasone administration, recently, no obvious evidence supports it. However, high erythrocyte sedimentation rate level in our patient might indicate bacterial superinfection, which could exacerbate with dexamethasone administration. Several mechanisms such as transient hypercoagulable state and insufficient blood supply due to splenomegaly were proposed for splenic infarction due to EBV infection. Since our patient remained asymptomatic during the disease, IM-associated splenic complications, including splenic infarction, should be kept in mind. Our patient underwent bilateral tonsillectomy and received conservative management for the splenic infarction. These two rare complications of acute EBV infection have not been reported simultaneously yet.