bluuebunny/crossref_metadata_2025 huggingface dataset:
DYNAMIC TWO-DIMENSIONAL NONLINEAR VIBRATION MODELING AND ANALYSIS FOR SHIELD TBM CUTTERHEAD DRIVING SYSTEM
Authors: Li Xianhong , Yu Haibin , Zeng Peng , Yuan Mingzhe , Sun Lanxiang , Zhao Yu
Published: April 2018

This paper establishes a general dynamic two-dimensional nonlinear time-varying (TDNLTV) vibration model with multi-drive shaft for shield tunnel boring machine (TBM) cutterhead driving system. Multiple- input and multiple- output (MIMO) state-space vibration model of cutterhead driving system is also presented. TDNLTV vibration model is simulated, and physical parameters’ effects on the vibration response are detailed investigated. A preliminary approach is proposed to reduce vibration or nonlinear vibration behaviors. Dynamic TDNLTV vibration model provides a basic foundation of fault detection and diagnosis (FDD) and health monitoring for cutterhead driving system.
A THEORETICAL AND EXPERIMENTAL STUDY FOR THE LOAD OPTIMIZATION OF GEAR-LIKE PROFILES BY USING FORWARD AND LATERAL EXTRUSION
Authors: Altinbalik Tahir , Ayer Önder
Published: April 2018

The main purpose of this research is to investigate the minimum deformation load by selecting a suitable forming method for manufacturing of gear-like sections and to compare the load estimation methods between Upper Bound Analysis and DEFORM-3D. Forward and lateral extrusion were chosen as two different forming methods. The effect of die transition geometry on deformation load was also investigated by straight tapered and cosine profiles. A newly kinematical admissible velocity field to analyze different profiles of extrusion dies was proposed by upper bound analysis. Al 1070 was used as working material. Experiments using five sets of dies with gear-like form were performed, and the measured forming load results were compared with the predictions of the theoretical solutions. Experiments were carried out on the 150 metric ton hydraulic press.
SUCTION INLET VORTEX INVESTIGATION AT LOW REYNOLDS NUMBERS
Authors: Ho Wei Hua , Idris Omar Faruq bin , New Tze How
Published: April 2018

Under certain flow conditions, when an inlet is aspirated in close proximity to a solid boundary, a vortex will form between the surface and the inlet. The formation and ingestion of such vortices could potentially lead to inefficient fluid suction by pumps or catastrophic damages in high-speed jet engines. Previous studies established the basic relationship of such inlet vortices formation threshold and geometry and flow conditions, though they were typically considered at significantly high Reynolds numbers. It remains unclear if there is a lower limit to the Reynolds number at which this phenomenon ceases to exist. This study shows that this phenomenon exists even at low Reynolds number of Re = 160. In particular, the results are generally in agreement with the previously established relationships at much higher Reynolds numbers but certain correlations are not as significant. This suggests that formation of inlet vortices may be less sensitive to Reynolds numbers effects than previously thought.
OPTIMAL DESIGN FOR A COMPOSITE WIND TURBINE BLADE WITH FATIGUE AND FAILURE CONSTRAINTS
Authors: Chehouri Adam , Younes Rafic , Ilinca Adrian , Perron Jean , Lakiss Hassan
Published: April 2018

The search for more efficient and sustainable renewable energies is rapidly growing. Throughout the years, wind turbines matured towards a lowered cost-of-energy and have grown in rotor size therefore stretched the role of composite materials that offered the solution to more flexible, lighter and stronger blades. The objective of this paper is to present an improved version of the preliminary optimization tool called Co-Blade, which will offer designers and engineers an accelerated design phase by providing the capabilities to rapidly evaluate alternative composite layups and study their effects on static failure and fatigue of wind turbine blades. In this study, the optimization formulations include non-linear failure constraints. In addition a comparison between 3 formulations is made to show the importance of choosing the blade mass as the main objective function and the inclusion of failure constraints in the wind turbine blade design.
ADAPTIVE NEURAL NETWORK CONTROL OF A HUMAN SWING LEG AS A DOUBLE-PENDULUM CONSIDERING SELF-IMPACT JOINT CONSTRAINT
Authors: Bazargan-Lari Yousef , Eghtesad Mohammad , Khoogar Ahmad R. , Mohammad-Zadeh Alireza
Published: April 2018

For human walking, the swing leg is usually modeled as a double pendulum. Considering a joint self-impact constraint at the knee joint of the double pendulum model is the main difference in this study. The primary objective of this research is to propose a nonlinear Adaptive Neural Network (ANN) for this system. By using Gaussian RBF networks, asymptotically stable tracking is attained. We will use the available data of normal human walking for the desired trajectories of the hip and knee joints. By simulation of the system, we perceive that the swing leg tracks the normal human gait with a negligible and tolerable error.
ANALYSIS OF JOINT FAILURES ON THE LATERAL UNDULATION GAIT OF A ROBOTIC SNAKE
Authors: Irani Rishad , Bauer Robert , North Lydia , Nicholson Michael , Nolan David , West Brennan
Published: April 2018

This paper describes the development of a biologically-inspired hyper-redundant wheeled snake robot and a corresponding computer simulator to study the effects that joint failures have on the resulting lateral undulation motion. Experiments and corresponding simulations were carried out to study the robotic snake’s lateral undulation gait as power to individual joints was turned off. The results showed that joint failures were most detrimental to the snake’s lateral undulation gait when they occurred in the front half of the snake, while joint failures occurring between the midpoint and tail of the robotic snake were found to be less critical and generally resulted in slight lateral drifts as the forward motion progressed. To help compensate for joint failures in the tail-half part of the robot, a bias term was added to the control algorithm. For the conditions tested in this research, the use of a bias term appeared to be effective at reducing the lateral drift.
ANALYSES OF FREE CONVECTION FLOW OF AN INCLINED PLATE EMBEDDED IN A DOUBLE LAYER POROUS MEDIUM
Authors: Beithou Nabil Ibrahim
Published: April 2018

Porous media offer wide practical applications, such as the use of the porous medium in solar water desalination systems to enhance water evaporation or condensation. Water condensation represents half of the desalination process. This study presents a simulation for the condensation process with double porous layers. This problem is simulated as the natural convection from an inclined plate embedded in a double layer porous medium; the plate was subjected to a constant wall temperature with variable layers thickness, permeability ratio and different plate angles. The effects of these parameters on the temperature distribution and total heat transfer were investigated. It has been found that the heat transfer rate increases with increasing the permeability ratio. Also increasing the layers thickness ratio in low permeability ratios, or keeping the layers ratio as minimum in the high permeability ratios are favorite. The inclination angle affects negatively the rate of heat transfer due to the buoyancy effect.
ON THE HYBRID-DRIVEN LINKAGE MECHANISM WITH ONE INPUT CYCLE CORRESPONDING TO TWO OUTPUT CYCLES
Authors: Soong Ren-Chung
Published: April 2018

A hybrid-driven five-bar linkage mechanism with one input cycle corresponding to two output cycles is presented. The proposed linkage mechanism is driven by a constant-speed motor and a linear motor, respectively. The output link can generate two same required output cycles during a single input cycle, while the rotational input link rotates with a constant angular speed, and the linear input link follows a reciprocating motion along a specified linear guide fixed on the rotational input link. The configuration, displacement relationship between the input and output links, and conditions of mobility of this proposed mechanism were studied, and a kinematic analysis was performed. The selection of the instantaneous motion trajectory of the linear input link and an optimal dimensional synthesis are also described. An example is provided to verify the feasibility and effectiveness of this methodology.
BEARING COMPOUND FAULT ACOUSTIC DIAGNOSIS BASED ON IMPROVED BLIND DECONVOLUTION ALGORITHM
Authors: Pan Nan , Wu Xing , Guo Yu
Published: April 2018

In the progress of bearing fault acoustic testing, signals picked up by acoustic sensors are usually mixed with fault source signals and other noise signals due to the complexity of mechanical signals and various interference sources. In order to solve the above problems, an improved blind deconvolution algorithm is put forward. The proposed algorithm applies adaptive generalized morphological filtering to the observed signals to retain their characteristic details, and then utilizes an OMP algorithm based on the minimum kurtosis to restore the periodical signals in the mixed signals in order to reduce the impact of the periodic components on blind separation. Finally, the improved Kullback–Leibler (KL) distance algorithm is employed to calculate the distances between independent components, which is used as the clustering index, and then to perform fuzzy C-means clustering. The experiment results of bearing compound fault extraction in real working-environment demonstrate the accuracy and reliability of the proposed algorithm.
A STUDY ON THE THERMAL CHARACTERISTICS OF THE GRINDING MACHINE APPLIED HYDROSTATIC BEARING
Authors: Kim Bo-Sung , Bae Gyeong-Tae , Kim Gwi-Nam , Moon Hong-Man , Noh Jung-Pil , Huh Sun-Chul
Published: April 2018

In order to activate the high precision and multi-functional machine tool, adequate technical level of the high-precision products is required. The hydrostatic bearings is used as a method for producing the high-precision products. The hydrostatic bearing has a relatively small run-out compared to its shape error by fluid film effect in hydrostatic state similar to pneumatic bearing and has high stiffness, load capacity and damping characteristics. In this study, we conducted a study on the thermal deformation of the grinding machine that has a great influence on the machining accuracy of the product. The temperature of the front bearing is 10°C or higher than the temperature of the rear bearing. Thermal deformation of the spindle was found to be dependent on the temperature of the hydrostatic bearing and could identify the overall thermal characteristics of the grinding machine.
CHARACTERISTICS OF AA7075-T6 AND AA6061-T6 FRICTION WELDED JOINTS
Authors: Rengarajan Sathish , Rao Vaddi Seshagiri
Published: April 2018

In this experimental study dissimilar materials of AA6061-T6 and AA7075-T6 having distinctive difference in physical and thermal properties were welded using continuous direct drive friction welding. High strength was achieved by high friction, upset pressure, low burn off length and medium rotational speed. Mechanical characterization and Micro structural behavior of the joint were given the paramount importance in this experimental analysis. The macro structure indicates that change in the direction of flow of grains perpendicular to the initial grain direction of the parent metal. Also the micro structural analysis at the interface zone showed the presence of eutectic particles that are formed as fragmented agglomerates.
MAPPING DISCRETE-TIME MODELS FOR DESCRIPTOR-SYSTEMS WITH CONSISTENT INITIAL CONDITIONS
Authors: Kawai Shin , Hori Noriyuki
Published: April 2018

Discretization of a regular continuous-time descriptor-system, whose initial condition is consistent with its input, is considered using a general mapping method presented in our previous paper. The proposed mapping discrete-time model is shown to be a proper discretization under the definition explained in the paper. This assures that the response of the mapping model approaches that of the continuous-time descriptor system as the sampling period approaches zero. The consistency of initial conditions for the discrete-time model is also studied and the long-standing issue of ambiguities surrounding irregularities of discrete-time responses at the initial time are clarified with a simple solution. A proper range of design parameters are investigated and their suitable choices suggested. To illustrate the use of the proposed method, a simple circuit that cannot be expressed in the ordinary state-space form is considered. Its responses to a sinusoidal input when started from the consistent and inconsistent initial conditions are simulated to show that the irregularities at the initial time can be overcome easily. The proposed technique provides a convenient simulation and design environment for handling discrete-time systems in a unified manner with consistency and ease.
DERIVATION AND VALIDATION OF A SPATIAL MULTI-LINK HUMAN POSTURAL STABILITY MODEL
Authors: Bourgeois Nicholas R. , Langlois Robert G.
Published: April 2018

In naval engineering and related disciplines, it is common for dynamic models of the human body to be used in conjunction with quantitative records of body and ship motions, in order to study human balance behaviour while performing various shipboard activities. Research in this area can lead to improvements in ship operations and designs that improve crew safety and efficiency. This paper presents the development of a new spatial 18 degree-of-freedom (DOF)1 ship-inverted pendulum model that incorporates 6 DOF ship motion and 3 DOF joints representing ankle, knee, hip, and neck motions. The derived model is then validated by comparing it to similar models derived using alternative methods but simulated under equivalent input conditions.
MECHATRONICS DESIGN OF AN X-BY-WIRE PROTOTYPE OF AN ELECTRIC VEHICLE
Authors: Mousavi Mir Saman Rahimi , Sauze Guillaume , Morozov Alexei , Angeles Jorge , Boulet Benoit
Published: April 2018

The concept of electric vehicle as a fully automated mobile robot – a.k.a. X-by-Wire, or Drive-by-Wire (DbW) concepts – is becoming more and more attractive in the modern automotive industry. This idea is based on replacing a mechanical subsystem by its electronic equivalent, which includes sensors and actuators, with a computer in-between. Three of the components, namely Throttle-by-Wire, Brake-by-Wire, and Steer-by-Wire, are the most complex and risky elements of the X-by-Wire technology. Moreover, these elements constitute the inherent part of the general DbW paradigm. This paper reports work-in-progress on the design and prototyping of a scaled-down 1 : 6 proof-of-concept model of a commercial vehicle with an integrated X-by-Wire system. The control for its components is discussed, while emphasizing the Steer-by-Wire actuator based on the Ackermann condition. The influence of heading velocity and turning angle on the slipping angle and path error of the model is discussed. The performance of the dynamics of the prototype is assessed over prescribed paths; deviations from the no-slip condition are evaluated.
IDENTIFICATION OF MAJOR LEAN WASTE AND ITS CONTRIBUTING FACTORS USING THE FUZZY ANALYTICAL HIERARCHY PROCESS
Authors: Arunagiri P. , Gnanavelbabu A.
Published: April 2018

Lean refers to the reduction of non-value added activities in industries. It focuses on seven types of lean waste. The significant challenge is to identify and reduce the major lean waste. With this objective, a survey was conducted in an international exhibition in India using a questionnaire. The collected data were analyzed using Analytic Hierarchy Process (AHP) software template to check consistency. Finding consistent results obtained in AHP satisfactory, ranking was carried out to find the major lean waste using fuzzy AHP. After the identification of the major lean waste, the major contributing factors for the waste were ranked using the Binary Logistic Regression (BLR). These contributing factors were further investigated for the waste elimination in the automobile component manufacturing industries.
OPTIMAL MOTION PLANNING OF A PLANAR PARALLEL MANIPULATOR WITH KINEMATICALLY REDUNDANT DEGREES OF FREEDOM
Authors: Abadi Bahman Nouri Rahmat , Taghvaei Sajjad , Vatankhah Ramin
Published: April 2018

In this paper, an optimal motion planning algorithm and dynamic modeling of a planar kinematically redundant manipulator are considered. Kinematics of the manipulator is studied, Jacobian matrix is obtained and the dynamic equations are derived using D’Alembert’s principle. Also, a novel actuation method is introduced and applied to the 3-PRPR planar redundant manipulator. In this approach, the velocity of actuators is determined in such a way to minimize the 2-norm of the velocity vector, subjected to the derived kinematic relations as constraints. Having the optimal motion planning, the motion is controlled via a feedback linearization controller. The motion of the manipulator is simulated and the effectiveness of the proposed actuation strategy and the designed controller is investigated.
ANALYSIS OF ENERGY ABSORBING DEVICE BASED ON DAMPED DYNAMIC VIBRATION ABSORBER
Authors: Zheng Zhongqiang , Yao Tao , Huang Peng , Chang Zongyu
Published: April 2018

Vibrations exist widely in tall buildings, vehicle systems, and ocean platform suffering from environmental loading such as wind, wave or earthquake. With the global concern on energy and environmental issues, energy absorbing from large-scale vibrations becomes a research frontier. A type of damped dynamics vibration energy absorber is built and analyzed in this paper, in which an added mass is connected to the vibration system with the electromagnetic transducer and spring. The relationships between electrical damping ratio, excitation frequency ratio and dimensionless power are analyzed in frequency domain. The optimal parameters for maximizing the power output are discussed in analytical form while taking the inherent mechanical damping of the system into account. The results indicate that when the system has suitable optimal excitation frequency ratio and damping ratio and so on, more power can be obtained. It is helpful for the design of energy absorber devices.
HOLE PROBLEMS IN A CIRCULAR PIEZOELECTRIC PLATE
Authors: Liang Yen-Chu , Sun Yun-Ping , Wu Lung-Nan
Published: April 2018

Due to the unique electric-mechanical coupling effects, piezoelectric materials are widely used in sensors and actuators. Not only in smart structures but also in structural health monitoring, the developments of piezoelectric materials combined with the micro electro mechanical system (MEMS) techniques make our lives totally different. This paper provides a series of numerical simulations about the circular piezoelectric plate with a hole in the plate by using the special boundary element method (BEM). The Green’s functions of BEM are obtained from the derivation of extended Stroh formalism. By this formalism, the analytical closedform solutions of hole in an infinite piezoelectric medium under various loading conditions are obtained. The results demonstrate the coupling effects with different boundary conditions in the circular plate, which will satisfy the requirements of the designers who need to use the products with the hole in the piezoelectric circular plate.
EFFECTS OF CHOKE RING DIMENSION ON THERMAL AND FLUID FLOW IN A SRU THERMAL REACTOR
Authors: Yeh Chun-Lang
Published: April 2018

The effects of choke ring dimension on the thermal and fluid flow in a practical SRU (sulfur recovery unit) thermal reactor are investigated numerically. It is found that zone 1 is a higher temperature region. In contrast, zone 2 is a lower temperature region. The average temperature for the rich oxygen supply is higher than that of normal oxygen supply. Without a choke ring, the temperature difference between zone 1 and zone 2 is smaller and the temperature in zone 1 becomes lower while the temperature in zone 2 becomes higher. In addition, the average temperature in zone 1 and the sulfur concentration at exit are the lowest without a choke ring. The reactor with a choke ring height of 0.74 m has the lowest peak temperature and the largest sulfur concentration at exit. Finally, with a choke ring height of 1.11 m, the blockage effect of the choke ring leads to the largest peak skin friction coefficient.
CHIMNEY-ENHANCED DESIGN APPLIED ON THE THERMAL MANAGEMENT OF LED VEHICLE HEADLAMP
Authors: Lin Sheam-Chyun , Chen Yu-Cheng , Wu Yu-Chun , Yen Hung-Cheng
Published: April 2018

LED vehicle headlamp consists of several high-power LEDs and thermal module inside an enclosed space, and locates near the high-temperature engine compartment. Certainly, these factors results in a challenging task on the thermal management of headlamp. Obviously, the temperature stratification inside this bounded region is an unfavorable phenomenon for the natural-convection thermal module. This study utilizes the chimney effect to achieve a more uniform temperature distribution and thus enhance the heat-dissipation ability. Firstly, an enclosed space is selected for executing the parametric study on the chimney geometry. Several effective alternatives are obtained and verified via both numerical and experimental means on the chimney design. Also, a significant 4.6°C reduction on LED junction temperature is attained on the best chimney-enhanced module. Then, these guidelines are applied to a commercial LED headlamp. Consequently, a range of 3.8 ~ 4.6°C decrease on LEDs is found for this innovative chimney thermal module.
CONTACT STRESS AND RADIAL STIFFNESS OF A CYLINDRICAL ROLLER BEARING WITH CORRECTED ROLLER GENERATOR
Authors: Chen Guanci , Wang Hailiang
Published: April 2018

A method has been developed to study the radial stiffness of a cylindrical roller bearing with corrected roller generator. First, the finite-length contact question of roller-race contact was solved by cutting contact surface into slices and considering the influences among slices by a flexibility coefficient matrix, which was more accurate than the traditional method. Further, the more precise load-approach function of the contact of race and roller with corrected generator was determined. Then, the radial stiffness of a cylindrical roller bearing has been derived by coupling this load-approach function into a complete bearing mechanical model. Results show that the corrected roller generator has a great influence on the bearing radial stiffness. The maximum stiffness difference among the cases of straight and crowned generators is 28.7%. The bearing radial stiffness decreases rapidly with the rise of profile maximum deviation hmax. It is worthy noting that there is a sudden change of stiffness with the adding of load when the bearing is with clearance.
DESIGN AND EVALUATION OF A RIDE COMFORT BASED SUSPENSION SYSTEM USING AN OPTIMAL STIFFNESS-DETERMINATION METHOD
Authors: Zhao Jing , Wong Pak Kin , Xie Zhengchao , Wei Caiyang , Zhao Rongchen
Published: April 2018

This paper focuses on a ride comfort based suspension (RCS) system using an optimal stiffness-determination method. The proposed RCS system is composed of a variable hydraulic damper with gas chamber (VHDGC) and an air spring. In this work, the detailed structure, modeling process and parameter sensitivity of the proposed VHDGC are presented. Moreover, the mathematical relationship between the proposed damper and the air spring is considered. Numerical results reveal that the ride comfort of the proposed RCS system can be greatly improved as compared with the passive suspension. In addition, the overall performance of the RCS system is also guaranteed. In sum, the proposed RCS system is a promising solution in improving the ride comfort of the vehicle.
STRUCTURAL IDENTIFICATION OF DYNAMIC SYSTEMS USING PARAMETER UPDATING REANALYSIS METHOD: EXPERIMENTAL INVESTIGATION USING THE MEASURED DATA
Authors: Han Kyoungbong , Cho Dooyong , Park Sun Kyu
Published: April 2018

In this study, the proposed parameter updating reanalysis method was directly used on the measured data of the structures. Structural reanalysis generates a correlated analytical model that defines the structure on applying the initially assumed baseline analytical model and is presented through the structure’s FRF (frequency response function). Two numerical tests were previously conducted in order to demonstrate the effectiveness of the suggested reanalysis method. The suggested method generates the correlated analytical model with higher precision, as compared to the existing method, despite the application of the noise factor to the observed data. The method initially proven by the numerical experiment of an actual structure was applied to a pseudo-dynamic test on the full-scale concrete pier. The results indicate that the proposed reanalysis is useful even for application to response data of the actual structure.
MAINTAINABILITY ANALYSIS AND EVALUATION OF FLEXIBLE CABLES BASED ON DELMIA
Authors: Tu Meixia , Chuan Lv , Wang Meihui , Zhou Dong , Xu Yiliu , Wan Bile , He Wenxing
Published: April 2018

This paper presents a virtual maintenance application for the maintainability analysis and evaluation of flexible cables to provide recommendations on the maintainability of products containing cables during the early stages of product design. This paper provides a methodology for complex products containing cables detecting the potential defects via virtual maintenance technology. An integrated platform for analyzing and evaluating cable maintenance in a virtual environment is designed. Then, based on the maintenance simulation platform DELMIA, a cable maintainability evaluation system is proposed. The system consists of an evaluation element, a evaluation criteria, and an evaluation method. A case study on aviation aircraft subsystem disassembly was used to validate the feasibility of virtual maintenance in improving cable maintainability designs.
Towards the appropriate synthesis of the four-bar linkage
Authors: Pickard Joshua K. , Carretero Juan A. , Merlet Jean-Pierre
Published: April 2018

Uncertainties are an inherent element in all mechanisms, arising from the manufacturing and assembly process or even from the operation of the device. In terms of synthesis routines for mechanisms, uncertainties are generally neglected since they are difficult to account for. In this work, the concept of appropriate design is utilized to develop routines that can more easily account for uncertainties in the geometrical parameters. These routines have been developed for linkages, specifically the four-bar linkage, and are capable of synthesizing the complete set of design solutions, referred to as allowable regions, for a set of desired coupler curve characteristics. The description of the desired coupler curve may contain any number of precision points and (or) trajectories. Several problems are solved in this work, including obtaining a representation of the coupler curve corresponding to a set of design parameters containing uncertainties, and synthesizing the appropriate designs for multiple descriptions of desired coupler curves. The results are quite promising and show great potential for using the appropriate design methodology for linkage synthesis.
Geometric optimization of a self-adaptive robotic leg
Authors: Fedorov Dmitri , Birglen Lionel
Published: April 2018

This paper demonstrates the self-adaptive capabilities of a two-degree-of-freedom Hoeckens-pantograph robotic leg (inspired by underactuated mechanical fingers) as well as its optimization, allowing it to overcome unexpected obstacles during its swing phase. A multi-objective optimization of the mechanism’s geometric parameters is performed using a genetic algorithm to highlight the trade-off between two conflicting objectives and select an appropriate compromise. The first of those objective functions measures the leg’s passive adaptation capability through a calculation of the input torque required to initiate the desired sliding motion along an obstacle. The second objective function evaluates the free-space trajectory followed by the leg endpoint using three criteria: linearity, stance ratio, and height-to-width ratio. In comparison with the initial geometry based on the Hoecken’s linkage, the selected final mechanism chosen from the Pareto front shows an important improvement of the adaptation capabilities, at the cost of a slight decrease in the stance phase duration. This paper expands on mechanical self-adaptive design philosophy, which has recently attracted a lot of attention in the field of grasping, to legged locomotion and paves the way for subsequent experimental validation of this approach.
Frobenius algebra with relaxed associativity constraint
Authors: Oziewicz Zbigniew , Page William Stewart
Published: April 2018

Frobenius algebra is formulated within the Abelian monoidal category of operad of graphs. A not necessarily associative algebra [Formula: see text] is said to be a Frobenius algebra if there exists a [Formula: see text]-module isomorphism. A new concept of a solvable Frobenius algebra is introduced: an algebra [Formula: see text] is said to be a solvable Frobenius algebra if it possesses a nonzero one-sided [Formula: see text]-module morphism with nontrivial radical. In the category of operad of graphs, we can express the necessary and sufficient conditions for an algebra to be a solvable Frobenius algebra. The notion of a solvable Frobenius algebra makes it possible to find all commutative nonassociative Frobenius algebras (Conjecture 10.1), and to find all Frobenius structures for commutative associative Frobenius algebras. Frobenius algebra allows [Formula: see text]-permuted opposite algebra to be extended to [Formula: see text]-permuted algebras.
Equivalence of two definitions of set-theoretic Yang–Baxter homology and general Yang–Baxter homology
Authors: Przytycki Józef H. , Wang Xiao
Published: April 2018

In 2004, Carter, Elhamdadi and Saito defined a homology theory for set-theoretic Yang–Baxter operators (we will call it the “algebraic” version in this paper). In 2012, Przytycki defined another homology theory for pre-Yang–Baxter operators which has a nice graphic visualization (we will call it the “graphic” version in this paper). We show that they are equivalent. The “graphic” homology is also defined for pre-Yang–Baxter operators, and we give some examples of its one-term and two-term homologies. In the two-term case, we have found torsion in homology of Yang–Baxter operator that yields the Jones polynomial.
On a conjecture about the quasirecognition by prime graph of some finite simple groups
Authors: Mahmoudifar Ali
Published: April 2018

It is proved that some finite simple groups are quasirecognizable by prime graph. In [A. Mahmoudifar and B. Khosravi, On quasirecognition by prime graph of the simple groups [Formula: see text] and [Formula: see text], J. Algebra Appl. 14(1) (2015) 12pp], the authors proved that if [Formula: see text] is a prime number and [Formula: see text], then there exists a natural number [Formula: see text] such that for all [Formula: see text], the simple group [Formula: see text] (where [Formula: see text] is a linear or unitary simple group) is quasirecognizable by prime graph. Also[Formula: see text] in that paper[Formula: see text] the author posed the following conjecture:

Conjecture. For every prime power [Formula: see text] there exists a natural number [Formula: see text] such that for all [Formula: see text] the simple group [Formula: see text] is quasirecognizable by prime graph.

In this paper [Formula: see text] as the main theorem we prove that if [Formula: see text] is a prime power and satisfies some especial conditions [Formula: see text] then there exists a number [Formula: see text] associated to [Formula: see text] such that for all [Formula: see text] the finite linear simple group [Formula: see text] is quasirecognizable by prime graph. Finally [Formula: see text] by a calculation via a computer program [Formula: see text] we conclude that the above conjecture is valid for the simple group [Formula: see text] where [Formula: see text] [Formula: see text] is an odd number and [Formula: see text].
Cohen–Macaulay binomial edge ideals of cactus graphs
Authors: Rinaldo Giancarlo
Published: April 2018

We classify the Cohen–Macaulay binomial edge ideals of cactus and bicyclic graphs.
On normal subgroups of M-groups
Authors: Chang Xuewu
Published: April 2018

The normal embedding problem of finite solvable groups into [Formula: see text]-groups was studied. It was proved that for a finite solvable group [Formula: see text], if [Formula: see text] has a special normal nilpotent Hall subgroup, then [Formula: see text] cannot be a normal subgroup of any [Formula: see text]-group; on the other hand, if [Formula: see text] has a maximal normal subgroup which is an [Formula: see text]-group, then [Formula: see text] can occur as a normal subgroup of an [Formula: see text]-group under some suitable conditions. The results generalize the normal embedding theorem on solvable minimal non-[Formula: see text]-groups to arbitrary [Formula: see text]-groups due to van der Waall, and also cover the famous counterexample given by Dade and van der Waall independently to the Dornhoff’s conjecture which states that normal subgroups of arbitrary [Formula: see text]-groups must be [Formula: see text]-groups.
Characterization of rings with nullity degree at least 1 4
Authors: Esmkhani M. A. , Jafarian Amiri S. M.
Published: April 2018

Let [Formula: see text] be a finite commutative ring with nonzero identity. The nullity degree of [Formula: see text], denoted by [Formula: see text], is the probability that the multiplication of two randomly chosen elements of [Formula: see text] is zero. In this paper, we characterize all rings [Formula: see text] with [Formula: see text]. Also, we study rings [Formula: see text] with [Formula: see text], where [Formula: see text] is a prime number.
Magnifying elements of semigroups of transformations with invariant set
Authors: Chinram Ronnason , Baupradist Samruam
Published: April 2018

Let [Formula: see text] be a semigroup of all transformations on a set [Formula: see text] Let [Formula: see text] be a fixed nonempty subset of [Formula: see text] and [Formula: see text] Then [Formula: see text] is a subsemigroup of [Formula: see text] which leaves a subset [Formula: see text] of [Formula: see text] invariant. If [Formula: see text] then [Formula: see text] In this paper, we give necessary and sufficient conditions for elements in [Formula: see text] to be left or right magnifying.
Seismic and geomorphic records of Antarctic Ice Sheet evolution in the Ross Sea and controlling factors in its behaviour
Authors: Anderson John B. , Simkins Lauren M. , Bart Phillip J. , De Santis Laura , Halberstadt Anna Ruth W. , Olivo Elisabetta , Greenwood Sarah L.
Published: April 2018

A robust collection of seismic and geomorphic data is used to examine the evolution of the Antarctic Ice Sheet within the Ross Sea Embayment. We use geomorphic data to reconstruct Last Glacial Maximum and post-Last Glacial Maximum ice sheet drainage and demonstrate retreat behaviours for the East Antarctic and West Antarctic sectors of the ice sheet. Using this framework, we then use seismic data and chronostratigraphic information from drill cores to reconstruct the long-term evolution of the ice sheet. Early ice sheet evolution during the Late Oligocene was characterized by isolated ice caps on bathymetric highs, followed by an interval of sediment infilling of rift basins and the development of more subdued relief in the eastern Ross Sea than in the western Ross Sea. Both ice sheets have experienced multiple episodes of expansion across the continental shelf since the Middle Miocene, with the frequency increasing during the Plio-Pleistocene. We conclude that seafloor bathymetry has been the principal control on ice sheet palaeodrainage and retreat behaviour since at least the middle Miocene, demonstrated by broad West Antarctic ice streams loosely guided by south to north cross-shelf troughs, whereas East Antarctic ice streams were funnelled through troughs that merge and converge around banks.
Fractures in shale: the significance of igneous intrusions for groundwater flow
Authors: MacDonald Alan M. , Davies Jeff
Published: April 2018

Research in Cretaceous shales from West Africa has demonstrated that significant permeability can develop within shales at shallow depths (<100 m), equivalent to a permeability of >1 m day
−1
. Much of the variation in permeability is related to the degree of burial metamorphism, with shales that have been altered and that approach the anchizone having the highest permeability and those that are largely unaltered (early diagenetic zone) having the lowest permeability. However, further research targeting largely unaltered shales dominated by smectite clay has shown that the presence of small igneous intrusions can radically alter the hydrogeology. Twenty-four exploratory boreholes were drilled into smectite-dominated shale and nine of these boreholes were targeted to small dolerite intrusions within the shale. The dolerite was intensely fractured at the intrusion edge, with significant zeolite growth along the fracture surfaces. The permeability in the fractured dolerite was the highest measured in any shale borehole, with transmissivities of up to 60 m
2
day
−1
measured from pumping tests. Fracturing was less where dolerite was intruded into sandstones, however, and the measured transmissivity was lower (<0.5 m
2
day
−1
). We postulate that the low permeability and high water content of the shale enabled high pressures to develop during intrusion, facilitating the development of fractures along the intrusion contact zone.
Dating protracted fault activities: microstructures, microchemistry and geochronology of the Vaikrita Thrust, Main Central Thrust zone, Garhwal Himalaya, NW India
Authors: Montemagni Chiara , Montomoli Chiara , Iaccarino Salvatore , Carosi Rodolfo , Jain Arvind K. , Massonne Hans-J. , Villa Igor M.
Published: April 2018

The timing of shearing along the Vaikrita Thrust, the upper structural boundary of the Main Central Thrust Zone in the Garhwal Himalaya, was constrained by combined microstructural, microchemical and geochronological investigations. Three different biotite–muscovite growth and recrystallization episodes were observed: a relict mica-1; mica-2 along the main mylonitic foliation; and mica-3 in coronitic structures around garnet during its breakdown. Electron microprobe analyses of biotite showed chloritization and a bimodal composition of biotite-2 in one sample. Muscovite-2 and muscovite-3 differed in composition from each other. Biotite and muscovite
39
Ar–
40
Ar age spectra from all samples showed both inter- and intra-sample discrepancies. Biotite step-ages ranged between 8.6 and 16 Ma and muscovite step-ages between 3.6 and 7.8 Ma. These ages cannot be interpreted as ‘cooling ages’ because samples from the same outcrop cooled simultaneously. Instead, the Ar systematics reflect sample-specific recrystallization markers. Intergrown impurities were diagnosed by the Ca/K ratios. The age data of biotite were interpreted as a mixture of true biotite-2 (9.00 ± 0.10 Ma) and two alteration products. The negative Cl/K–age correlation identified a Cl-poor muscovite-2 (>7 Ma) and a Cl-rich, post-deformational, coronitic muscovite-3 grown at ≤5.88 ± 0.03 Ma. The Vaikrita Thrust was active at least from 9 to 6 Ma at
c.
600°C; its movement had ended by 6 Ma.

Supplementary material:
Thermometric and
39
Ar–
40
Ar data are available at
https://doi.org/10.6084/m9.figshare.c.4069076
Nocturnal swallowing and arousal threshold in individuals with chronic spinal cord injury
Authors: Rizwan Aliza , Sankari Abdulghani , Bascom Amy T. , Vaughan Sarah , Badr M. Safwan
Published: April 2018

Respiratory complications are potential causes of death in patients with spinal cord injury (SCI). Nocturnal swallowing could be related to transient arousals and could lead to fragmented sleep in SCI patients. However, the impact of nocturnal swallowing on breathing and sleep physiology in SCI is unknown. The objectives of this study were 1) to determine whether nocturnal swallowing is more common in SCI than in able-bodied (AB) subjects, 2) to determine the role of nocturnal swallowing on arousal threshold (ArTh) in SCI individuals with sleep-disordered breathing (SDB), and 3) to determine the effect of continuous positive airway pressure (CPAP) treatment on nocturnal swallowing. A total of 16 SCI and 13 AB subjects with SDB completed in-laboratory polysomnography with a pharyngeal catheter. A swallowing event (SW) was defined as a positive spike in pharyngeal pressure and was used to calculate the swallow index (SI) defined as a number of SW/total sleep time. Each SW was assessed for a relationship to the sleep stages and respiratory cycle phases, and associated arousals and ArTh were calculated. SI was higher in the SCI group compared with AB subjects during wake and different sleep stages ( P < 0.05). SWs were found to be significantly higher in the late expiratory phase in the group with SCI compared with the other respiratory phases and were eliminated by CPAP ( P < 0.05). ArTh for the subjects with SCI was significantly lower ( P < 0.05) compared with the AB subjects. Nocturnal swallowing is more common in SCI than in AB individuals who have SDB, particularly during the expiratory phase. The ArTh is significantly lower in SCI (indicating increased arousal propensity), which may contribute to the mechanism of sleep disturbances in SCI.

NEW & NOTEWORTHY Nocturnal swallowing is common in patients with chronic spinal cord injury (SCI) and is associated with frequent arousals from sleep. The lower arousal threshold during sleep in SCI may contribute to the mechanism of sleep disturbances that are commonly found in cervical and high thoracic SCI. Continuous positive airway pressure may play a therapeutic role in alleviating nocturnal swallowing, which may contribute to reduced risk of aspiration.
Nonlinear Dynamic Analysis of High‐Voltage Overhead Transmission Lines
Authors: Zhang Meng , Zhao Guifeng , Li Jie
Published: April 2018

According to a generalized Hamilton’s principle, three‐dimensional (3D) nonlinear vibration equations for overhead transmission lines that consider geometric nonlinearity are established. Based on the characteristics of an actual transmission line, the 3D equations are simplified to two‐dimensional equations, and the nonlinear vibration behavior of transmission lines is investigated by combining theoretical analysis with numerical simulation. The results show that transmission lines have inherently nonlinear vibration characteristics. When in free vibration, a transmission line can undergo nonlinear internal resonance, even when its initial out‐of‐plane energy is relatively low; as its initial out‐of‐plane energy increases, the coupling of in‐plane and out‐of‐plane vibration becomes stronger. When forced to vibrate by an external excitation, due to the combined action of internal and primary resonance, the vibration energy of a transmission line transfers from the out‐of‐plane direction to the in‐plane direction that is not directly under the excitation, resulting in an increase in the dynamic tension and the displacement amplitude of the transmission line. Increasing damping can consume the vibration energy of a transmission line but cannot prevent the occurrence of internal resonance.
Penetrating Sacral Injury with a Wooden Foreign Body
Authors: Fattahi Arash , Jahanbakhshi Amin , Shahivand Ardeshir , Dastmalchi Alireza
Published: April 2018

Spinal penetrating trauma has a complex neurosurgical management. This study presents a 55-year-old male admitted in our center with a 1 × 1 centimeter laceration on the sacral area skin due to a wooden penetrating object. The computed tomography (CT) of the spine revealed a hypodense penetrating object that was introduced from the posterior aspect of the sacrum into dural space and then stopped in the S1 vertebral body. We performed a laminectomy of intact superior portion of the S1 lamina and released the wood from the surrounding bone, and finally, we pulled it out.
Preaugmentation Soft Tissue Expansion: A Report of Four Pilot Cases
Authors: Asa’ad Farah , Bellucci Gionata , Ferrantino Luca , Trisciuoglio Davide , Taschieri Silvio , Del Fabbro Massimo
Published: April 2018

This pilot study aimed at investigating the safety and feasibility of pre-augmentation soft tissue expansion (STE). Tissue expanders of different sizes (from 240 to 1300 mm3) were implanted subperiosteally in four patients requiring vertical and/or horizontal bone augmentation, and left in situ for 20–60 days, according to the expander size. Guided bone regeneration was carried out after STE completion. Horizontal and vertical bone gains were analyzed through CBCT. Optical scanning and superimposition of cast models were used for volumetric analysis. The mean soft tissue volume increase was 483.8 ± 251.7 mm3. Horizontal bone gain averaged 3 mm in two successfully expanded sites while one case had a vertical bone gain of 8 mm. Despite promising outcomes in bone and soft tissue gain, the present technique needs improvement before being applied routinely in everyday dental practice.
High Mobility Group Box Protein 1 Serves as a Potential Prognostic Marker of Lung Cancer and Promotes Its Invasion and Metastasis by Matrix Metalloproteinase-2 in a Nuclear Factor-κB-Dependent Manner
Authors: Wu Xiaojin , Wang Weitao , Chen Yuanyuan , Liu Xiangqun , Wang Jindong , Qin Xiaobin , Yuan Dawei , Yu Tao , Chen Guangxia , Mi Yanyan , Mou Jie , Cui Jinpeng , Hu Ankang , E Yunxiang , Pei Dongsheng
Published: April 2018

Several studies have reported a significant role of high mobility group box protein 1 (HMGB1) in lung cancer. Nevertheless, there is a lack of knowledge regarding the expression of HMGB1 and its correlation with the clinicopathological features of lung cancer. In addition, the potential molecular mechanisms underlying the role of HMGB1 in lung cancer are still unknown. We therefore investigated the clinicopathological and prognostic significance as well as the potential role of HMGB1 in the development and progression of lung cancer. HMGB1 expression in the tumor tissues of the cohort correlated with clinicopathological features. Moreover, lung cell migration and invasion were significantly increased after treatment with HMGB1. The matrix metalloproteinase-2 (MMP-2) expression and activity were upregulated after treatment with HMGB1, while the upregulated expression of MMP-2 stimulated by HMGB1 in lung cancer cells was significantly reduced with the blockage of si-p65. These results indicated that HMGB1 expression was significantly associated with lung cancer progression. We also showed that HMGB1 promoted lung cancer invasion and metastasis by upregulating the expression and activity of MMP-2 in an NF-κB-dependent manner. Taken together, these data suggested that HMGB1 may be a potential prognosis and therapeutic marker for lung cancer.