bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation of five rice nonendosperm tissue‐expressed promoters and evaluation of their activities in transgenic rice
Authors: Li Hao , Li Juan , Xu Rongfang , Qin Ruiying , Song Fengshun , Li Li , Wei Pengcheng , Yang Jianbo
Published: November 2017

Using promoters expressed in nonendosperm tissues to activate target genes in specific plant tissues or organs with very limited expression in the endosperm is an attractive approach in crop transgenic engineering. In this article, five putative nonendosperm tissue‐expressed promoters were cloned from the rice genome and designated POsNETE1, POsNETE2, POsNETE3, POsNETE4 and POsNETE5. By qualitatively and quantitatively examining GUSplus reporter gene expression in transgenic rice plants, POsNETE1‐POsNETE5 were all found to be active in the roots, leaves, stems, sheaths and panicles but not in the endosperm of plants at different developmental stages. In addition, POsNETE2, POsNETE4 and POsNETE5 were also inactive in rice embryos. Among these promoters, POsNETE4 and POsNETE5 exhibited higher activities in all of the tested tissues, and their activities in stems, leaves, roots and sheaths were higher than or comparable to those of the rice Actin1 promoter. We also progressively monitored the activities of POsNETE1‐POsNETE5 in two generations of single‐copy lines and found that these promoters were stably expressed between generations. Transgenic rice was produced using POsNETE4 and POsNETE5 to drive a modified Bt gene, mCry1Ab. Bt protein expressed in the tested plants ranged from 1769.4 to 4428.8 ng/g fresh leaves, whereas Bt protein was barely detected in the endosperm. Overall, our study identified five novel nonendosperm tissue‐expressed promoters that might be suitable for rice genetic engineering and might reduce potential social concern regarding the safety of GMO crops.
Expression and assembly of largest foreign protein in chloroplasts: oral delivery of human FVIII made in lettuce chloroplasts robustly suppresses inhibitor formation in haemophilia A mice
Authors: Kwon Kwang‐Chul , Sherman Alexandra , Chang Wan‐Jung , Kamesh Aditya , Biswas Moanaro , Herzog Roland W. , Daniell Henry
Published: November 2017

Inhibitor formation is a serious complication of factor VIII (FVIII) replacement therapy for the X‐linked bleeding disorder haemophilia A and occurs in 20%–30% of patients. No prophylactic tolerance protocol currently exists. Although we reported oral tolerance induction using FVIII domains expressed in tobacco chloroplasts, significant challenges in clinical advancement include expression of the full‐length CTB‐FVIII sequence to cover the entire patient population, regardless of individual CD4+ T‐cell epitope responses. Codon optimization of FVIII heavy chain (HC) and light chain (LC) increased expression 15‐ to 42‐fold higher than the native human genes. Homoplasmic lettuce lines expressed CTB fusion proteins of FVIII‐HC (99.3 kDa), LC (91.8 kDa), C2 (31 kDa) or single chain (SC, 178.2 kDa) up to 3622, 263, 3321 and 852 μg/g in lyophilized plant cells, when grown in a cGMP hydroponic facility (Fraunhofer). CTB‐FVIII‐SC is the largest foreign protein expressed in chloroplasts; despite a large pentamer size (891 kDa), assembly, folding and disulphide bonds were maintained upon lyophilization and long‐term storage as revealed by GM1‐ganglioside receptor binding assays. Repeated oral gavages (twice/week for 2 months) of CTB‐FVIII‐HC/CTB‐FVIII‐LC reduced inhibitor titres ~10‐fold (average 44 BU/mL to 4.7 BU/mL) in haemophilia A mice. Most importantly, increase in the frequency of circulating LAP‐expressing CD4+CD25+FoxP3+ Treg in tolerized mice could be used as an important cellular biomarker in human clinical trials for plant‐based oral tolerance induction. In conclusion, this study reports the first clinical candidate for oral tolerance induction that is urgently needed to protect haemophilia A patients receiving FVIII injections.
Comparative Probabilistic Assessment of Occupational Pesticide Exposures Based on Regulatory Assessments
Authors: Pouzou Jane G. , Cullen Alison C. , Yost Michael G. , Kissel John C. , Fenske Richard A.
Published: November 2017

Implementation of probabilistic analyses in exposure assessment can provide valuable insight into the risks of those at the extremes of population distributions, including more vulnerable or sensitive subgroups. Incorporation of these analyses into current regulatory methods for occupational pesticide exposure is enabled by the exposure data sets and associated data currently used in the risk assessment approach of the Environmental Protection Agency (EPA). Monte Carlo simulations were performed on exposure measurements from the Agricultural Handler Exposure Database and the Pesticide Handler Exposure Database along with data from the Exposure Factors Handbook and other sources to calculate exposure rates for three different neurotoxic compounds (azinphos methyl, acetamiprid, emamectin benzoate) across four pesticide‐handling scenarios. Probabilistic estimates of doses were compared with the no observable effect levels used in the EPA occupational risk assessments. Some percentage of workers were predicted to exceed the level of concern for all three compounds: 54% for azinphos methyl, 5% for acetamiprid, and 20% for emamectin benzoate. This finding has implications for pesticide risk assessment and offers an alternative procedure that may be more protective of those at the extremes of exposure than the current approach.
Central venous catheters for chronic hemodialysis: Is “last choice” never the “right choice”?
Authors: Dumaine Chance S. , Brown Robert S. , MacRae Jennifer M. , Oliver Matthew J. , Ravani Pietro , Quinn Robert R.
Published: November 2017

Since the publication of the first vascular access clinical practice guidelines in 1997, the global nephrology community has dedicated significant time and resources toward increasing the prevalence of arteriovenous fistulas and decreasing the prevalence of central venous catheters for hemodialysis. These efforts have been bolstered by observational studies showing an association between catheter use and increased patient morbidity and mortality. To date, however, no randomized comparisons of the outcomes of different forms of vascular access have been conducted. There is mounting evidence that much of the difference in patient outcomes may be explained by patient factors, rather than choice of vascular access. Some have called into question the appropriateness of fistula creation for certain patient populations, such as those with limited life expectancy and those at high risk of fistula‐related complications. In this review, we explore the extent to which catheters and fistulas exhibit the characteristics of the “ideal” vascular access and highlight the significant knowledge gaps that exist in the current literature. Further studies, ideally randomized comparisons of different forms of vascular access, are required to better inform shared decision making.
Preoperative screening and intervention for mild anemia with low iron stores in elective hip and knee arthroplasty
Authors: Pujol‐Nicolas Andrea , Morrison Rory , Casson Clare , Khan Sameer , Marriott Allan , Tiplady Christopher , Kotze Alwyn , Gray William , Reed Mike
Published: November 2017

BACKGROUND

Preoperative anemia in patients undergoing elective hip and knee arthroplasty is associated with increased postoperative morbidity and mortality, red blood cell (RBC) transfusion, and length of stay (LOS). The aim of this study was to assess the effect of optimizing hemoglobin (Hb) levels before elective primary hip and knee arthroplasty.

STUDY DESIGN AND METHODS

This is a prospective comparative cohort study of patients who underwent elective hip and knee arthroplasty before (control) and after (intervention) the launch of a Hb optimization program. Patients with anemia followed an agreed upon algorithm dependent on their medical history and blood variables taken on listing for surgery. The primary outcome for this study was the requirement for allogenic RBC transfusion. Secondary outcomes included hospital LOS, admission to critical care, readmission, medical complications, incidence of thromboembolic events, mortality, and costs.

RESULTS

A total of 1814 control patients operated between February 2012 and February 2013 were compared to 1622 intervention patients operated between February 2013 and May 2014. In the intervention group transfusion was significantly reduced (108 [6%] vs. 63 [4.1%], p = 0.005) as well as readmission (81 [4.5%] vs. 48 [2.3%], p= 0.020) and critical care admission (23 [1.3%] vs. 9 [0.5%], p = 0.030). LOS was significantly reduced from 3.9 days to 3.6 days (p = 0.017). The saving for the cohort was £263,000 ($342,000).

CONCLUSIONS

Algorithm‐led preoperative anemia screening and management in elective arthroplasty was associated with reduced RBC transfusion, readmission, critical care admission, LOS, and costs.
Kinematic behavior of a novel pedicle screw‐rod fixation system for the canine lumbosacral joint
Authors: Zindl Claudia , Litsky Alan S. , Fitzpatrick Noel , Allen Matthew J.
Published: November 2017

Objective

To determine the biomechanical behavior of a novel distraction‐stabilization system, consisting of an intervertebral distraction bolt, polyaxial screws, and connecting rods, in the canine lumbosacral spine.

Study design

Biomechanical study.

Sample population

Cadaveric canine lumbosacral spines (L4‐Cd3) (N = 8).

Methods

Cadaveric lumbosacral spines were harvested, stripped of musculature, mounted on a 4‐point bending jig, and tested in extension, flexion, and lateral bending using nondestructive compressive axial loads (0‐150 N). Angular displacement was recorded from reflective optical trackers rigidly secured to L6, L7, and S1. Data for primary and coupled motion were collected from intact spines, after destabilization at L7‐S1, and following surgical stabilization with the new implant system.

Results

As compared with the intact spine, laminectomy resulted in a modest increase in angular displacement at L6‐L7 and a marked increase at L7‐S1. Instrumentation significantly reduced motion at the operated level (L7‐S1) with a concomitant increase at the adjacent level (L6‐L7).

Conclusion

The combination of a polyaxial pedicle screw‐rod system and intervertebral spacer provides a versatile solution of surgical stabilization of the lumbosacral joint following surgical decompression in the canine lumbosacral spine. The increase in motion at L6‐L7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this question.

Clinical relevance

These results support the feasibility of using this new implant system for the management of degenerative lumbosacral disease in dogs. The increase in motion at L6‐L7 may suggest the potential for adjacent level effects and clinical trials should be designed to address this question.
Estimation of Short-and Long-Term Probability Distributions of Wave-Induced Loads Acting on a Cruise Vessel in Extreme Seas
Authors: Rajendran Suresh , Fonseca Nuno , Guedes Soares C.
Published: November 2017

A time domain code based on strip theory is applied to calculate the probability distributions of relative motions and bending moments of a cruise ship in a set of extreme seas. The code includes two levels of complexity. The simpler one combines linear radiation and diffraction forces with nonlinear Froude–Krylov forces, hydrostatic forces, and shipping of green water on the bow. Cummins formulation is used to represent the radiation forces. The second approach is a generalization of the first one and, although the formulation is based on the linear assumption (of the radiation forces), the effects of body nonlinearity are considered by a simplified method: the memory functions, infinite frequency added masses, and the radiation restoring coefficients are assessed at each time instant as function of the instantaneous wetted surface. A similar procedure is used to calculate the diffraction forces. The code is used to analyze the responses of a cruise ship in a set of extreme sea conditions. The short-term nonlinear responses are represented by empirical probability distributions, obtained from the nonlinear time domain simulations, and the quality of the predictions is assessed by comparing with model tests experimental data. Finally, the long-term value of the bending moment is calculated from the short-term distribution of the nonlinear loads in a few extreme sea states selected based on coefficient of contribution method, and the results are compared with the International Association of Classification Societies (IACS) rule bending moment.
Some Dynamic Properties of Contact Patches in Bolted Joints
Authors: Lancereau Damien P. T. , Goyder Hugh G. D. , Ind Philip , Brown Daniel
Published: November 2017

The dynamics of structures built-up from components connected by bolted joints are not well understood. Experiments were conducted with bolted joints in a shear configuration in which instantaneous vibration frequencies and damping could be measured. A system with bolted joints was excited and the free vibration decay measured. As the vibration decays, the damping decreases and the frequencies increase.

This suggests a new interpretation for the contact patch in a bolted joint, involving bound, slipping and alternating regions. The changing size of the bound region controls the instantaneous frequencies and the relative displacement inside the slipping region and the alternating region controls the damping behaviour.

Shims of different lengths enabled the behaviour of the contact patch to be investigated. A clear trend exists between the length of the shims and the non-linear dynamic behaviour. The introduction of multiple shims did not increase the damping or alter the dynamic nonlinear behaviour. The introduction of grease into the bolted joint increased the damping but oil did not. The vibration measurements enable the size of the contact patch to be estimated.
Palpation-Like Devices of Ball Indentation for Softness Evaluation of Biological Tissue
Authors: Sakuma Atsushi , Shirai Yuki
Published: November 2017

Indentation technique for the mechanical evaluation of soft materials like biological tissue is discussed in order to develop the medical device of palpation. Here, the Hertzian contact theory is functionally extended to measure the mechanical characteristics of thin, viscous and fragile tissue, and then it is also modified to evaluate the elasticity and friction of the soft materials. The modification of the contact theory is applied to manufacture a trial device experimentally, and its availability is studied by using the FE analysis with the boundary condition of contact and friction.
Enhance Sustainability Benefits Through Scaling-Up Bioenergy Production From Terrestrial and Algae Feedstocks
Authors: Mirkouei Amin , Kardel Kamran
Published: November 2017

The techno-economic analysis outcomes of bioenergy production compared with traditional energy indicate that the existing production technologies are not promising, however environmental analyses demonstrate that bioenergy products support cross-cutting sustainability and strategic analysis efforts. Therefore, utilization of bio-products, such as bio-oil and biofuels, is expected to increase in the near future due to environmental pressures. The overarching goal is to balance the primary dimensions of sustainability using both distributed and centralized conversion technologies. To this end, this research proposes a conceptual decision making framework to examine biomass-derived energy production system infrastructures and process-level operations. This framework encompasses three phases (i.e., 5-ton study, 50-ton study, and 500-ton study), using techno-economic, financial risks, cross-cutting assessments to scale-up bioenergy production, foster technology commercialization, and enhance sustainability benefits. The motivation behind the proposed framework lies in inherent limitations of the existing bioenergy conversion technologies and production systems. As an application of this research, a sustainable bioenergy economy fueled by innovative conversion technologies is examined in the state of Georgia to produce (at least one billion gasoline gallon equivalent) hydrocarbon biofuels from underutilized feedstocks (e.g., terrestrial and algae). The outcomes can address national priorities: promote energy security and reduce dependence on imported oil, promote the use of diverse domestic and clean energy resources, establish advanced bioindustries and rural economies, and mitigate environmental impacts from fossil fuel production and consumption.
Fault Detection in Rotating Machinery by Using the Modal State Observer Approach
Authors: Leão Leandro de S. , Cavalini Aldemir Ap. , Morais Tobias S. , de Melo Gilberto Pechoto , Steffen Valder
Published: November 2017

The presence of transversal cracks in rotating shafts can lead to catastrophic failures, which imply economic losses and security issues. In the last years, an important attention has been devoted to this subject, leading to the development of several vibration-based structural health monitoring approaches. In this paper, a fault detection technique based on the so-called modal state observer is applied to detect transversal cracks in rotating machines. The Luenberger state observer is described in modal domain to determine the most affected vibration modes due to the crack presence. A cracked rotor composed by a flexible horizontal shaft, two rigid discs, and two self-aligning ball bearings is used for illustration purposes. The additional flexibility introduced by the crack is calculated by using the linear fracture mechanics theory. The breathing behavior of the crack is simulated according to the Mayes’ model, in which the crack transition from fully open to fully closed is described by a cosine function. The obtained results lead to the conclusion that the modal state observer is a potential technique to detect cracks in rotating machines.
Research on Incomplete Design and Generating Theory of the Relief Surfaces of Dual-Cone Double Enveloping Hourglass Worm Gear Hob
Authors: Chengjie Rui , Haitao Li , Jie Yang , Wenjun Wei , Xuezhu Dong
Published: November 2017

The relief surfaces of the cutting teeth of a dual-cone double enveloping hourglass worm gear hob cannot be ground automatically until now because all of teeth have different profiles and different spiral angles with each other. The land width and the relief angle of the hob are two important factors when using the hob to hob a worm gear. In order to improve the precision of this type worm pair, the land width and the relief angle of the hob need to be machined accurately and effectively. For the purpose that the land width and the relief angle could be machined precisely, an incomplete design and generating theory of the relief surfaces of the dual-cone double enveloping hourglass worm gear hob is put forward in this paper. The mathematical model of the incomplete design and generating theory of the relief grinding of the hob is built. According to the model, a series of data of the motion parameters when grinding different points of the land edges of the different hob teeth are solved out. Using those data of the motion parameters on a four-axis hourglass worm-grinding machine, a machining simulation is built and the results of the simulation show that the relief surfaces of the hob can be ground continuously, and the land width and the relief angle are consistent with the design.
Numerical Analysis of Dry Friction Damping Effect of Tie-Boss Couplings on Three Blade Bundle
Authors: Pesek Ludek , Pust Ladislav , Bula Vitezslav , Cibulka Jan
Published: November 2017

This contribution deals with a design of bladed wheel model with tie-boss couplings for numerical and experimental dynamic analysis. Besides modal analysis of the linearized wheel model a non-linear dynamical response of the three blade bundle with friction couplings in the tie-bosses were computed for description of a friction damping. Three-dimensional FE model with friction contacts was developed in the program ANSYS 15.0. The Augmented Lagrangian method was used to compute contact normal pressures and friction stresses. The friction coupling was modeled by the Isotropic Coulomb’s law. For a description of the friction coefficient, its dependence on relative velocity was considered. The damping ratio of the friction damping was evaluated from the envelope of free vibration attenuations after short harmonic excitation. The first experimental results for validation of the numerical model are discussed at the end.
Lower-Order Active Disturbance Rejection Control and Frequency Analysis of High Order System
Authors: Zhang Ruiqing , Zhang Shubo , Xue Yali , Hu Yu , Wang Wendi
Published: November 2017

Linear active disturbance rejection control (LADRC) has been paid much attention in academic and industrial fields. However, the selection of the order for LADRC controller design and the choice of parameter b0 in system correcting are key facts which are still being faced by designer. In this paper, an effective method about how to select the order of LADRC and the parameter b0 is given first. Frequency analysis often used by engineers for designing controller, the normal transfer function form of LADRC is constructed, so the loop gain, close loop transfer function and disturbance transfer function to a general high-order system are presented and can be easily used. The example shows that the proposed method is easy to apply and verified the lower-order LADRC can obtain the better effective than PID and high-order LADRC, and the frequency response analysis of a thermal power plant is elaborated and the simulation result indicates that LADRC has a strong robustness against the large variation of parameters in the plant mode.
What is a Prototype?: Emergent Roles of Prototypes From Empirical Work in Three Diverse Companies
Authors: Lauff Carlye , Kotys-Schwartz Daria , Rentschler Mark E.
Published: November 2017

This paper explores the nature of prototypes from three diverse companies in the fields of consumer electronics, footwear, and medical devices. It is part of a larger qualitative research study developing a prototyping framework grounded in the emergent findings from practice and detailed inductive inquiry. In this paper, we describe the methods for setting up an appropriate research design, highlighting the conceptual framework, means for data collection and analysis, and validity. Then, we describe the emergent findings, introducing a modified definition of a prototype and the three roles of prototypes.

This research is a contribution to the field of design theory and methodology by adding new knowledge about prototypes from companies. Prototyping is an essential part of product development, and yet it is one of the least formally explored areas of design. The significance of this work lies in its ability to gain insights into the role of prototyping in the natural work environment, which has not been holistically documented. By using diverse industries, we will build and test our framework across them all to ensure validity.
Design Optimization of a Prismatic-Revolute-Revolute Joint Hand for Grasping From Unconstrained Vehicles
Authors: Backus Spencer B. , Dollar Aaron M.
Published: November 2017

Adding grasping and manipulation capabilities to unconstrained vehicles such as UAVs, AUVs, and small space craft so that they can deliver cargo, grasp and retrieve objects, perch on features in the environment, and even manipulating their environment is an ongoing area of research. However, these efforts have relied heavily on structuring the interaction task and have predominantly utilized existing gripper designs that were not specialized for the platform or task. In this paper, we present a parametric model of a novel underactuated hand design that is composed of prismatic-revolute-revolute joint fingers. This kinematic configuration attempts to minimize disturbance forces to the body of the vehicle while achieving stable grasps on a wide range of objects under significant positional uncertainty. In particular, this paper investigates the impact of various design parameters, including the relative link lengths and force allocation across the three joints, on grasping performance and suggests optimal design parameters for a prototype hand.
A Network-Based Computational Model for Creative Knowledge Discovery Bridging Human-Computer Interaction and Data Mining
Authors: Chen Liuqing , Shi Feng , Han Ji , Childs Peter R. N.
Published: November 2017

As a branch of computational creativity, Creative Knowledge Discovery (CKD) aims to search for valuable, previously unknown, or ignored, relationships between concepts, and create new patterns by taking advantage of existing patterns or by analogy to patterns in other domains. Data mining has been widely used in CKD research. However, most proposed mining algorithms lack a theoretical basis for computational creativity due to their origins in traditional knowledge discovery in databases (KDD), which stymies novelty. In addition, integration of human-computer interaction (HCI) is often overlooked for assisting discovery of creative knowledge despite the human end user possessing problem solving intelligence. To address these issues, a network-based computational model bridging human-computer interaction and data mining is proposed arising from an initial investigation on the theoretical basis of computational creativity. A corresponding creativity evaluation methodology, Multi-dimensional In-depth Long-term Case studies (MILCs) is also introduced. In order to evaluate the proposed model, a web tool called B-Link has been developed. Longitudinal interviews and a questionnaire survey have been conducted by applying the MILCs evaluation method. The success of finding novel items and obtaining inspiration in interviews as well as the positive survey rating results of all five creativity metrics have suggested that B-Link is able to guide thinking processes and aid creative knowledge discovery effectively, which demonstrates the capability of the proposed network-based computational creativity model integrating human-computer interaction and data mining.
Design Exploration of Affordable Refreshable Braille Display Technology for Low-Income Visually Impaired Users
Authors: Walker Anthony S. , Sangelkar Shraddha
Published: November 2017

People with visual disability need assistance in reading and writing by converting text to braille. Braille allows tactile display of the information for the visually impaired. Refreshable braille displays are commonly available in developed countries for a high price with the number of cells the display contains being the most influential factor on that price. Low-income blind individuals from developing countries cannot afford an expensive refreshable braille display, which in turn limits their access to digital information. The purpose to this paper is to explore design options for reducing the cost of refreshable braille displays. The paper begins with a summary of currently available refreshable braille displays on the market and their features. Next, the design requirements are explored for developing a low-cost device for visually impaired users in the developing countries. The paper also explains the state-of-the-art technologies for actuating the braille dots that may reduce the cost of the device. Finally, the recommendations for reducing the cost of these displays are presented.
Kinematic Analysis of Multi-4-Bar Mechanisms Using Algebraic Geometry
Authors: Piipponen Samuli , Hyry Eero , Arponen Teijo
Published: November 2017

The configuration spaces (c-space) of mechanisms and robots can in many cases be presented as an algebraic variety. Different motion modes of mechanisms and robots are found as irreducible components of the variety. Singularities of the variety correspond usually (but not necessarily) to intersections of irreducible components/motion modes of the configuration space. A well-known method for finding the modes is the prime (and/or primary) decomposition of the constraint ideal corresponding to the mechanisms specific constraint map. However the direct computation of these decompositions is still in many cases too exhausting at least for standard computers. In this paper we present a method to speed up the decomposition significantly. If the mechanism consists or is constructed of subsystems whose c-space can be decomposed in feasible time then the whole decomposition of the c-space of the mechanism can be constructed from the decompositions of the subsystems. Here we concentrate on the 4-bar-subsystems but the approach generalizes naturally to more complicated subsystems as well. In fact the method works for all mechanisms which are constructed of subsystems whose decomposition is already known or can be computed. Further we present a way to investigate the nature of singularities which relies on the computation of the tangent cone at singular points of the c-space and the investigation of the primary decomposition of the tangent cone itself and partially its connection to intersection theory of algebraic varieties.
Reduction of Vibration in Spur Gears by an Asymmetric Tooth Profile With High Contact Ratio
Authors: Fujikawa Ryo , Ikejo Kiyotaka , Ibaraki Soichi , Nagamura Kazuteru
Published: November 2017

Gear drive is a mechanism transmitting a power and a motion through the teeth contact. The number of teeth in contact changes during a mesh cycle. That raises a discontinuity of the mesh stiffness, and causes a gear vibration. The discontinuity implies a direct relationship with the contact ratio of the gear pair. In general, the high contact ratio more than two decreases the discontinuity of the mesh stiffness. Therefore, the increase of the contact ratio is able to reduce the vibration and the noise in the gear drives. An adoption of a helical gear pair is a method to obtain two or more contact ratio. However, that provides a thrust force and a difficulty to machine and assemble. For a spur gear pair, though it is possible to increase the contact ratio by stretching the tooth depth, the tooth thickness may reduce or be excessively sharp at the tooth tip on the addendum circle.

In this study, we designed and made a high contact ratio spur gear pair with an asymmetric tooth profile. The gear pair has a large tooth depth to increase the contact ratio, and the asymmetric tooth profile to prevent the sharpness of tooth at the tip circle. In the running test, the vibration and the noise were measured. Consequently, we succeeded in a reduction of vibration and noise in spur gear drives with the asymmetric tooth profile.
Robust Optimization With Parameter and Model Uncertainties Using Gaussian Processes With Limited Samples
Authors: Zhang Yanjun , Li Mian
Published: November 2017

Uncertainty is inevitable in engineering design. The existence of uncertainty may change the optimality and/or the feasibility of the obtained optimal solutions. In simulation-based engineering design, uncertainty could have various types of sources, such as parameter uncertainty, model uncertainty, and other random errors. To deal with uncertainty, robust optimization (RO) algorithms are developed to find solutions which are not only optimal but also robust with respect to uncertainty. Parameter uncertainty has been taken care of by various RO approaches. While model uncertainty has been ignored in majority of existing RO algorithms with the hypothesis that the simulation model used could represent the real physical system perfectly. In the authors’ earlier work, a RO framework was proposed to consider both parameter and model uncertainties using the Bayesian approach with Gaussian processes (GP), where metamodeling uncertainty introduced by GP modeling is ignored by assuming the constructed GP model is accurate enough with sufficient training samples. However, infinite samples are impossible for real applications due to prohibitive time and/or computational cost. In this work, a new RO framework is proposed to deal with both parameter and model uncertainties using GP models but only with limited samples. The compound effect of parameter, model, and metamodeling uncertainties is derived with the form of the compound mean and variance to formulate the proposed RO approach. The proposed RO approach will reduce the risk for the obtained robust optimal designs considering parameter and model uncertainties becoming non-optimal and/or infeasible due to insufficiency of samples for GP modeling. Two test examples with different degrees of complexity are utilized to demonstrate the applicability and effectiveness of the proposed approach.
Numerical Modeling and Analysis of Piston Lubrication for Flexible Bodies Through Elastohydrodynamics and Modal Reduction Method
Authors: Kim Seongsu , Choi Juhwan , Rhim Sungsoo , Choi Jin Hwan
Published: November 2017

An analysis for operating characteristics of piston lubrication system is performed based on the numerical model in the area of fluid-structure interaction. A numerical model with an integration of elastohydrodynamics and multi-flexible-body dynamics (MFBD) is developed to analyze lubrication characteristics such as oil film thickness and pressure. In particular, elastic deformation of components in piston lubrication system through modal reduction method is reflected on elastohydrodynamic analysis. The oil film pressure evaluated from elastohydrodynamic analysis is used as external force to calculate the elastic deformation of flexible bodies in multi-flexible-body dynamics (MFBD) again. A series of process proposed in this study is available for the analysis of realistic elastohydrodynamic lubrication phenomenon. Moreover, asperity contact effect is also implemented. Finally, a numerical example for the piston lubrication system is also demonstrated.
Coupled Dynamic Characteristics of Wind Turbine Gearbox Driven by Ring Gear Considering Gravity
Authors: Zhang Aiqiang , Wei Jing , Qin Datong , Hou Shaoshuai , Lim Teik C.
Published: November 2017

Gravity is usually neglected in the dynamic modeling and analysis of the transmission system, especially in some relatively lightweight equipment. The wind turbine gearbox weight up to tens of tons or even hundreds of tons, and the effects of gravity have not been explored and quantified. In order to obtain accurate vibration response predictions to understand the coupled dynamic characteristics of the wind turbine gear transmission system, a comprehensive, fully coupled, dynamic model is established using the node finite element method with gravity considered. Both time-domain and frequency-domain dynamic responses are calculated using the precise integration method with various excitations being taken into account. The results indicate that gravity has a significant impact on the vibration equilibrium position of central floating components, but the changing trends are different. Gravity does not change the composition of the excitation frequency, but will have a certain impact on the distribution ratio of the frequency components. And the high frequency vibrations are hardly affected by gravity. In addition, the load sharing coefficient is greater when gravity is taken into account, both of internal gearing and external gearing system. When the planet gears have a certain position error in accordance with certain rules, the load sharing performance of the system will be better.
Development of Reduced Order Thermomechanical Model Using Floating Frame of Reference Formulation
Authors: Yamashita Hiroki , Arora Rohit , Kanazawa Hiroyuki , Sugiyama Hiroyuki
Published: November 2017

In this paper, a reduced order thermomechanical model based on the Craig-Bampton component mode synthesis method is extended to the floating frame of reference formulation for the thermomechanical analysis of flexible multibody systems. To this end, coupled structural and thermal equations of finite element models are partitioned in terms of the internal and interface coordinates, each of which consists of the structural and thermal coordinates. Both deformation including the thermal effect and temperature in the internal region are then defined by a linear combination of the thermomechanical fixed-interface normal modes and thermomechanical constraint modes to account for structural and thermal modes associated with external forces and heat sources applied to the system. The final form of equations include equations of motion associated with a flexible body that incorporates thermal deformation and the reduced order heat equations that describe the transient change in the temperature over the flexible body. For this reason, the inertia coupling of the reference motion and the thermal deformation is automatically considered using the floating frame of reference formulation. Both equations are integrated forward in time simultaneously using general multibody dynamics computer algorithms to account for the coupled structural and thermal behavior of flexible multibody systems. Several numerical examples are presented to demonstrate the use of the numerical procedure developed in this study.
Vibration Control of a Rotating Cantilever Beam by Using the Giant Magnetostrictive Actuator
Authors: Xu Xueping , Han Qinkai , Chu Fulei
Published: November 2017

The dynamic model and control strategy of a rotating cantilever beam are investigated in the paper. The magnetostrictive layer is applied as the actuator and the nonlinear constitutive relation is analyzed. The kinetic energy and potential energy of the beam are obtained. The Hamilton method and Galerkin approach are adopted to obtain and disperse the dynamic equations, respectively. The negative feedback control methodology is used in the control system, which is performed by the solenoid coils. Numerical results show that the magnetostrictive control method is effective and plays the role of damping in the dynamic equations. The nonlinear constrictive characteristics of the magnetostrictive material can affect the control results deeply and should be paid enough attention. The magnetostrictive control performances are influenced by many parameters such as the bias magnetic field, control gain and pre-stress etc.
Design and Integration of a Two-Digit Exoskeleton Glove
Authors: Refour Eric , Sebastain Bijo , Ben-Tzvi Pinhas
Published: November 2017

This paper presents the design and integration of a two-digit exoskeleton glove. The proposed glove is designed to assist the user with grasping motions, such as the pincer grasp, while maintaining a natural coupling relationship among the finger and thumb joints, resembling that of a normal human hand. The design employs single degree of freedom linkage mechanisms to achieve active flexion and extension of the index finger and thumb. This greatly reduces the overall weight and size of the system making it ideal for prolonged usage. The paper describes the design, mathematical modeling of the proposed system, detailed electromechanical design, and software architecture of the integrated prototype. The prototype is capable of recording information about the index finger and thumb movements, interaction forces exerted by the finger/thumb on the exoskeleton, and can provide feedback through vibration. In addition, the glove can serve as a standalone device for rehabilitation purposes, such as assisting in achieving tip or pulp pinch. The paper concludes with an experimental validation of the proposed design by comparing the motion produced using the exoskeleton glove on a wooden mannequin with that of a natural human hand.
Investigation of Helmet Based on Origami Structures
Authors: Yang Yang , Nara Chie , Chen Xiaoshi , Hagiwara Ichiro
Published: November 2017

The earthquake is a natural disaster which is irresistible and hard to forecast. In the earthquakes, the helmets play an important role in protecting the head of people. The traditional helmets have some disadvantages of storability. Even very few foldable helmets have been designed, the price of them are expensive. In order to overcome these disadvantages, and from the prospect of application to origami-engineering, we challenged to invent a foldable helmet based on origami structures. We designed the helmet using the origami structures of accordion cover origami structure/honeycomb origami structure and the low-priced energy absorption material of corrugated cardboard. Because the designed origami helmet is necessary to satisfy the safety performance, the impact FEM analyses are done to investigate the mechanical characteristics of the designed origami helmets. And the experiments are also done to confirm the safety performance of the designed helmets. Finally, the numerical analysis results are compared with the experimental results.
Body Gesture-Based User Interaction in Design Review
Authors: Xiao Yu , Peng Qingjin
Published: November 2017

Human-computer interactions (HCI) are essential in computer-aided design (CAD) systems. Replacing the traditional mouse and keyboard by gestures for the design input has aroused wide interests of researchers to improve the naturalness and intuitiveness of HCI. A gesture-based design review system is proposed in this paper for the CAD model review. Human gestures are captured using Microsoft Kinect. Based on the review of frequently-used CAD commands in the design review process, six commands including translation, scaling, rotation, navigation, exploding and assembly are proposed using human body gestures for the design review process. FAAST is used as a middleware to transmit skeleton joint signals from Kinect to the review system via VRPN. Applications of the interface show the proposed method is able to effectively trigger required design operations via gestures. Results of the user test shows that intuitiveness and naturalness of HCI are improved via gestures compared to traditional methods of the design input.
A Robust Control Interpretation on Generalized Separation Principle of Active Disturbance Rejection Control
Authors: Jin Huiyu , Lan Weiyao
Published: November 2017

Generalized separation principle (GSP) is a main reason why active disturbance rejection control (ADRC) is easy to use. In this short note, GSP is interpreted from the respective of robust control. Linear active disturbance rejection control (LADRC) is described as an interconnection of two subsystems, while to design LADRC is a process to tuning the gains of them. Small gain theorem guarantees separately tuning is possible. That is why GSP works.
A Survey: Towards Understanding Emergent Behavior in Complex Engineered Systems
Authors: Soria Zurita Nicolás F. , Tumer Irem Y.
Published: November 2017

The design of complex engineered systems is challenging, especially in early design stages due to the complex emergent behavior that often results in unforeseen failures. Emergent behavior is a distinctive aspect of systems in which the exhibited behavior of the system is more complex than the behavior of the individual components that shape the system. Understanding the emergent behavior is critical to perform an accurate assessment of the designed system. The objective of this paper is to explore the different existing concepts, methods, and approaches used by researchers to understand and manage emergent behavior in complex systems. We provide a critical review of the emergence concept to discern what characteristics about the causal process it reflects, so it can be used or implemented in further research in complex engineered systems. Specifically, this research explores the current state of-the-art on emergence, and identifies possible gaps in the research literature. We present different approaches used by engineers to deal with emergent behavior in different research areas such as Multiagent Systems (MAS), System of Systems (SOS), and Emergence Engineering.
A Novel Six-Bar Mechanism for Executing Motion Trajectories of Sit-to-Stand Transformation in a Multifunctional Mobility Assist Device
Authors: Purwar Anurag , Jadhav Akshay
Published: November 2017

This paper presents a novel six-bar Sit-to-Stand (STS) linkage mechanism integrated in a multi-functional assistive device1, that helps improve mobility of individuals with lower extremity weaknesses. The six-bar linkage follows the J-shaped trajectory of the shoulder-joint and maintains orientation of the supporting bar for the comfort and ergonomics. An overall goal was to design a device that is comfortable to the user during STS transformation, compact, light-weight, portable and one that requires minimum number of external actuators. By following the natural posture and movement of certain joints, a biomechanically correct STS motion is achieved. A natural motion ensures minimum stresses on joints and muscles and if the user can move their legs, they can undergo ambulation therapy and stimulate functional neural pathways. Dynamic analysis is done on the mechanism to design a frame and to select actuators for lifting a person weighing 300lbs. The device was tried by individuals with lower extremity weaknesses and the results showed that it lifts users well and also helps balance and stabilize them during ambulation.
A Method to Determine the Optimal Checking-Fixture Layout for Gauge Repeatability
Authors: Slon Christopher M. , Pandey Vijitashwa
Published: November 2017

This paper proposes a method for finding the optimal fixture layout to achieve acceptable gauge repeatability in the inspection process of a non-rigid part. Currently, there are no rigorous means of evaluating the effectiveness of a fixture layout for a part in terms of gauge repeatability until actual parts and gauges are available late in the product development process. Changes to the part design or modifications to the gauge at this late stage are usually costly and can result in program delays, incurring substantial costs. This paper proposes an approach to arrive at the best locator layout for gauge repeatability early in the part design phase thereby avoiding costly and time-consuming changes during the build phase. The method is implemented using a commercially available tolerance stack software with finite element analysis combined with a specially coded genetic algorithm. The method’s effectiveness is demonstrated through the improvement in gauge repeatability from an arbitrary datum scheme to the optimal datum scheme in a notional design problem as well as an actual production part. We also demonstrate that the commonly accepted datum scheme of using a primary plane along the largest dimension of a part may be highly suboptimal for gauge repeatability.
An Evaluation of ARFIMA Programs
Authors: Liu Kai , Zhang Xi , Chen YangQuan
Published: November 2017

Strong coupling between values at different time that exhibit properties of long range dependence, non-stationary, spiky signals cannot be processed by the conventional time series analysis. The ARFIMA model, which employs the fractional order signal processing techniques, is the generalization of the conventional integer order models — ARIMA and ARMA model. Therefore, it has much wider applications since it could capture both short-range dependence and long range dependence. For now, several software have developed functions dealing with ARFIMA processes. However, it could be a big difference, if using different numerical tools for time series analysis. Time to time, being asked about which tool is suitable for a specific application, the authors decide to carry out this survey to present recapitulative information of the available tools in the literature, in hope of benefiting researchers with different academic backgrounds. In this paper, 4 primary functions concerning simulation, fractional order difference filter, estimation and forecast are compared and evaluated respectively in the different software and informative comments are also provided for selection.