bluuebunny/crossref_metadata_2025 huggingface dataset:
Abrasive Waterjet Profile Cutting of Thick Titanium/Graphite Fiber Metal Laminate
Authors: Pahuja Rishi , Ramulu M. , Hashish M.
Published: February 2017

Fiber Metal Laminates (FML) are one of the most advanced engineered materials used in aerospace industry. The combination of metallic sheets interspersed in composite laminates in one hybrid material system provides higher impact and corrosion resistance when compared with their monolithic counterparts. However, due to the difference in machining responses for different material phases, conventional machining often induce damages and defects, affecting the cost and structural performance of the part. This research study investigates the machinability of thermoplastic Titanium Graphite (TiGr) FML. The feasibility and machinability of contouring thick (7.6 mm–10.5 mm) TiGr through Abrasive Waterjet (AWJ) process was studied in terms of machined kerf characteristics — taper ratio and surface quality. The effect of a wide range of process parameters was investigated such as geometric variables (mixing tube aspect ratio and orifice bore size), kinetic variables (water pressure, jet traverse speed) and abrasive load ratio on the machining quality. Predictive mathematical regression models were developed through Analysis of Variance (ANOVA) in order to optimize the process. Alongside, machined surface was examined to inspect the topological characteristics, material removal mechanism, and machining induced damage (micro-defects) and distortion through Surface Profilometry, Scanning electron and optical microscopy. A comparison was drawn between conventional and AWJ trimming of TiGr to demonstrate the superiority and high speed machining of AWJ with less damage.
Innovative Mechatronic Approach to Redesign a Punch and Bind Machine
Authors: Figueiredo Luís , Sousa João , Monteiro Luís , Mendonça João , Machado José
Published: February 2017

This paper focuses on the redesign of an innovative punch and bind machine. Business machines can be integrated with recent technology that enables productivity and efficiency. Integrating smart technologies in the existing traditional business machines will ease the evolution of these systems. The creation of a pilot platform is required, which enables further developments on servitization. In order to ease and increase the office document binding rate, as well as reduce the probability of errors to occur, efforts were made to develop a measuring system which allows the correct measurement of the document and simultaneously specify the appropriate binding spine. Developments were made in a system that allows the inserted spine verification. In addition, a system for automated document binding, with the correct position of paper sheets was developed. The integrated platform allowing communication between all systems is presented. The new system has several advantages in both its hardware design and its underlying sensors, providing a significant improvement in performance and upgradability over existing systems. The mechatronic system combines mechanical position sensing with electronics implementation of the hardware and the basic algorithms. This solution consists in a system that allows the punch and bind optimization of a range of sheets of paper, plastic or other materials.
Modeling and Simulation of Shoulder-Humerus Complex via Multibody Dynamics for a Walking Elder Using a Cane
Authors: Duan Shanzhong (Shawn)
Published: February 2017

The shoulder is a very mobile joint. Because of the mobility, the shoulder is considered to have an inherent weakness. The joint consists of three major bones, the clavicle, scapula and humerus. These bones are more commonly called the collarbone, shoulder blade, and upper arm bone, respectively. Collectively, the shoulder is referred to as the scapula-humeral-clavicle complex. The joint between the humerus and scapula is a ball-socket joint. The joint between the scapula and acromial process allows for some movement but is primarily fixed. The ligaments, tendons, and muscles surround the shoulder to provide stability, movement, and limit the amount of rotation.

In this paper, a multibody dynamics model of the shoulder-upper arm complex is presented. Three major bones clavicle, scapula, and Humerus in the shoulder-upper arm complex are represented by rigid bodies. The soft tissues such as tendons, ligaments, and muscles are modeled as springs and actuators respectively attached to the rigid bodies. The joints between the bones are expressed as ideal kinematic joints. Kane’s equations are then used to derive equations of motion of this multibody system. Based on the model, an elder who uses a cane with his or her shoulder-upper arm complex force to support his or her upper body weight during walking is analyzed. Commercial computer software is used to create the multibody shoulder-upper arm complex computational model and then carry out simulation. The model may be utilized in motion analysis of elderly people and sports medicine to study fatigue mechanism and prevent injuries of the shoulder-upper arm complex.
Development of an Active Biomimetic-Controlled Transfemoral Knee Prosthesis
Authors: Bernal-Torres Mario G. , Medellín-Castillo Hugo I. , Arellano-González Juan C.
Published: February 2017

Commercial available knee prostheses are still limited because most of them comprise passive elements that store and deliver energy during the gait cycle, but without providing additional energy. This inability to provide additional energy affects the performance of passive prostheses, which in some cases demands up to 60% of additional metabolic energy to perform a gait cycle. Recent research works have focused on the design of active knee prostheses, including the development and implementation of control strategies such as electromyographic (EMG) signals. However, the results of such implementations reveal that these control strategies are still limited because of the relatively long time response and inaccurate movements.

This paper presents the design of a new biomimetic-controlled knee prosthesis for transfemoral amputation. The aim is to contribute to the development of simple and effective active knee prostheses. The proposed prosthesis consists of a polycentric mechanism obtained from the body-guidance kinematics synthesis of a four bar linkage. This synthesis is based on the natural movements of the human knee, taking into account the shortening effect of the leg during the walking process to avoid trips. The prosthetic knee mimics the human motion of the healthy leg by means of an echo-control strategy. An experimental prototype has been implemented and tested on a workbench. The experimental results have demonstrated the usability of the proposed biomimetic active knee prosthesis.
A Method for Characterizing Model Fidelity in Laser Powder Bed Fusion Additive Manufacturing
Authors: Assouroko Ibrahim , Lopez Felipe , Witherell Paul
Published: February 2017

As Additive Manufacturing (AM) matures as a technology, modeling methods have become increasingly sought after as a means for improving process planning, monitoring and control. For many, modeling offers the potential to complement, and in some cases perhaps ultimately supplant, tedious part qualification processes. Models are tailored for specific applications, focusing on specific predictions of interest. Such predictions are obtained with different degrees of fidelity. Limited knowledge of model fidelity hinders the user’s ability to make informed decisions on the selection, use, and reuse of models. A detailed study of the assumptions and approximations adopted in the development of models could be used to identify their predictive capabilities. This could then be used to estimate the level of fidelity to be expected from the models. This paper conceptualizes the modeling process and proposes a method to characterize AM models and ease the identification and communication of their capabilities, as determined by assumptions and approximations. An ontology is leveraged to provide structure to the identified characteristics. The resulting ontological framework enables the sharing of knowledge about indicators of model fidelity, through semantic query and knowledge browsing capabilities.
Electrically Addressable Hierarchical Carbon Nanotube Forests
Authors: Davis Benjamin , Muralidharan Nitin , Pint Cary , Maschmann Matthew R.
Published: February 2017

Hierarchical, branched carbon nanotube (CNT) forest assemblies were created by synthesizing a second generation of CNTs directly from the alumina-coated surface of a parent CNT forest. First, a parent CNT forest generation was synthesized using floating catalyst chemical vapor deposition (CVD) in which gaseous argon and hydrogen are flowed into a tube furnace, along with a controlled flow rate of ferrocene nanoparticles suspended in xylene solvent. Next, a thin alumina coating was applied to the parent CNT forest using atomic layer deposition (ALD). The ALD process pulses alternating gases of water vapor and trimethylaluminum (TMA) and is repeated for 100 cycles, yielding a 10nm coating. This coating adheres to the outer walls of the larger CNTs and serves as a supportive surface to enable the growth of a second CNT generation. Finally, a second CNT generation was synthesized from the parent CNT forest using a floating-catalyst CVD method similar to that used for the parent generation. The relatively low areal density of the parent CNT generation allows for gas-phase additive processing (i.e. ALD and floating catalyst CVD) to occur deep within the volume of the original parent CNT forest.

Transmission electron microscopy analysis of the hierarchical CNT forests shows that second-generation CNTs nucleate and grow from the alumina-coated walls of the parent generation rather than nucleating from the original growth substrate, as has been previously reported. Further, physical confinement of the second-generation catalyst particle on the external surface of the parent generation CNTs (28 nm average diameter) leads to small-diameter CNTs (8 nm average) for the second generation. Further, radial breathing modes are detected by Raman spectroscopy, indicating single-walled or few-walled CNTs are synthesized in the second generation.

The hierarchical forests exhibit many desirable properties compared to single generation forests. Because the second generation CNTs within the interstitial regions of the parent CNT forest, they increase the structural rigidity of the cellular CNT forest morphology, increasing in mechanical stiffness by ten-fold, relative to the parent CNT forest. Further, we demonstrate that electrical continuity between the CNT generations is retained. Because a thin alumina buffer layer exists between CNT generations, electrical continuity is not guaranteed. Cyclic voltammetry and electrochemical impedance spectroscopy are used to characterize the electrical resistance elements within the hierarchical forest. This hierarchical structure offers a new avenue to tailor the performance of CNT forests and offers performance enhancements for applications in thermal interfaces, electrical interconnects, dry adhesives and energy generation and storage.
Comparative Study of Analytical Expressions to Estimate the Deep Drawing Force of Cylindrical and Rectangular Parts
Authors: Rivas Menchi Aarón , Medellín Castillo Hugo I. , de Lange Dirk F. , García Zugasti Pedro de J.
Published: February 2017

The deep drawing process has been widely used in the industry because it eliminates costly operations such as welding and machining. However, there are many parameters involved that affect the quality of the final products. One of the main parameters of the deep drawing process is the maximum deep drawing force (DDF) or drawing load, which is the maximum force required to perform a particular deep drawing operation. This maximum DDF is needed to define the required capacity of the press, and to calculate the deep drawing work and the process efficiency. Several analytical expressions to estimate the maximum DDF have been proposed in the literature, particularly for cylindrical parts. However, few research works have focused on analyzing the prediction performance of these expressions.

In this paper, the performance of different analytical expressions to estimate the maximum DDF of cylindrical and rectangular parts, is evaluated and compared. Initially, several expressions proposed by different researches for the maximum DDF of cylindrical parts are presented. Then, these expressions are transformed into new expressions for the maximum DDF of rectangular parts by using different concepts of equivalency, such as the equivalent diameter concept. Finally, the prediction performance of all the expressions for both cylindrical and rectangular deep drawing is analysed and compared using experimental data from the literature. The performance is evaluated in terms of the prediction error. The results have suggested that the analytical expressions involving the largest number of parameters have a superior prediction performance than the analytical expressions involving less parameters.
Piecewise Fifth Order Spline Interpolation for Line Heating Forming Process
Authors: Champliaud Henri , Feng Zhengkun , Provencher David , Tousignant Danick , Gholipour Javad
Published: February 2017

A fifth order piecewise spline interpolation model has been developed for computing the evolving geometry of a plate deformed by line heating thermal gradients. 3D formulations are presented and applied to continuously derivable geometries to demonstrate the capability of the methodology. Then the developed formulation is used to form gradually, with a sequence of heating lines, a 3D shape from an initially flat plate. The geometric results obtained from finite element simulations with three heating lines are used to illustrate where heating lines should be applied on a flat plate to achieve the intended geometry of a workpiece. Furthermore, it is shown that applying the developed piecewise fifth order spline interpolation model to the same flat plate produces results very close to the ones obtained from the thermal structural FE simulations.
A Correlative CFD Study Between Recirculation Area and FPM in VHC Design
Authors: Oliveira Ricardo F. , Teixeira Senhorinha F. , Marques Helena Maria Cabral , Teixeira José Carlos
Published: February 2017

A major part of asthma treatment is made by the use of preventive inhalation drugs. The Pressurized Metered-Dose Inhalator (pMDI) has been the backbone device for this treatment, due to its simplicity, portability and widely acceptance. But no device comes without its limitations, and pMDI is hard to handle properly by elders and children < 5 years old, resulting in reduced amount of drug to the patient lungs. Add-on devices (e.g. spacers) were developed to mitigate the need for coordination and reduce the oral/throat deposition, namely the Valved Holding Chambers (VHC). These devices are incorporated with a one-way valve and a chamber that allows the spray droplets to rapidly reduce their size upon release on a stagnated and confined flow. The VHC main ability, in terms of efficiency, is to reduce the coarse fraction (i.e. particles with diameter > 4.7μm) of the plume by impaction and allow the fine fraction to be inhaled by the patient.

The VHC geometry will play a very importance role in the entrapment of small drug particles (i.e. fine fraction). The hypothesis proposed by this study is that a small particle has more probability to be trapped in geometries with higher recirculation areas (and stagnation zones). These macro vortices will cause a particle with small Stokes number to be entrapped; to assess this hypothesis a numerical study was modelled.

The numerical study was carried out on an idealized geometry of a VHC device, using a 2D axisymmetric approach. Different coordinates for a “corner” point, were tested. FLUENT® was used to obtain the unsteady numerical solution, meshes were generated using Meshing® software from ANSYS®. Once the flow field is stabilized (around 0.6s), a pMDI spray was injected into the domain during 0.1 seconds and the simulation continued until perform 4 seconds. The simulation takes into account the vaporization of the HFA-134a propellant present in the droplets of spray and a User Defined Function (UDF) for modeling the particle -wall interaction.

The post-processing of the results included the calculation of the recirculation area and the Fine Particle Mass (FPM) that exits the domain.

Results show that the percentage of recirculation area decreases linearly with the increase of axial position of the corner point, and rapidly increases with the radial displacement. FPM results are not so linear; nevertheless they show opposite behavior to the recirculation area.

Additionally, results show that high recirculation area reduces the amount of FPM emitted. Data can be correlated through a power function (FPM = 101.805*Area−0.244; R2 = 0.460). Results are more strongly correlated for lower values of radial displacement.

The results seem to corroborate the hypothesis that smaller particles tend to be entrapped by recirculation areas.
Investigation of Hydrophobic Nanoporous Particle Liquids for Impact Protection
Authors: Hsu Yi , Liu Yingtao
Published: February 2017

Recently, the development of hydrophobic nanoporous liquids has drawn increased attention, especially for the applications of energy absorption and impact protection. Although significant amount of research has been conducted to synthesis and characterize materials to protect structures from impact damage, the tradition methods needed to convert kinetic energy to other forms, such as heat and cell bulking, during impact protection. Due to their high energy absorption efficiency, hydrophobic nanoporous particle liquids are one of the most attractive impact mitigation materials. When impacted, such particles directly trap liquid molecules inside the non-wetting surface of nanopores in the particles. The captured impact energy is simply stored temporarily and isolated from the original energy transmission path.

In this paper we investigate the energy absorption efficiency of multiple nanoporous particles and liquids. Inorganic nanoporous silica nanoparticles are investigated as the hydrophobic materials. Nanoporous particle liquids are prepared by dispersing the nano-materials in deionized water. The effects of small molecular promoters, such as methanol and ethanol, on energy absorption efficiency, are studied in this paper. The energy absorption efficiency of these liquids is experimentally characterized using an Instron mechanical testing frame and in-house develop stainless steel hydraulic cylinder system under quasi-static load conditions.
Taguchi Design of Experiment for the Optimization of Electrochemical Polishing of Metal Additive Manufacturing Components
Authors: Brent Denikka , Saunders Tyler Alyssa , Garcia Moreno Francisco , Tyagi Pawan
Published: February 2017

3D Printing (Additive Manufacturing, AM) offers benefits such as lower costs, easier customization and creating complex functional products. However, utilization of AM components in the engineering applications may be severely limited by the high surface roughness. For most industrial uses the high surface roughness can cause stress concentrations, premature failure, and corrosion susceptibility. Unfortunately, conventional surface reduction processes like machining, extrude honing, and sandblasting, may not be feasible for the complex AM components. This research focused on exploring electropolishing as a viable surface smoothing approach for the AM components. However, electropolishing is a multivariable process and requires extensive parameter optimization. We have employed Taguchi’s design of experiment to find the suitable combination of electropolishing parameters. Our Taguchi analysis yielded a set of optimum experimental parameters for the electropolishing of steel AM components. This experimental process reduced the roughness of AM component surfaces as much as ∼63%.
Optimizing Cutting Planes for Advanced Joining and Additive Manufacturing
Authors: Massoni Brandon , Campbell Matthew I.
Published: February 2017

While additive manufacturing allows more complex shapes than conventional manufacturing processes, there is a clear benefit in leveraging both new and old processes in the definition of new parts. For example, one could create complex part shapes where the main “body” is defined by extrusion and machining, while small protruding features are defined by additive manufacturing. This paper looks at how optimization and geometric reasoning can be combined to identify optimal separation planes within a complex three-dimensional shapes. These separations indicate the joining processes in reverse. The optimization method presents possible manufacturing alternatives to an engineering designer where optimality is defined as a minimization of cost. The process identifies the cutting planes as well as the combination of processes required to join the individual parts together. The paper presents several examples of complex shapes and describes how the optimization finds the optimal results.
Mechanical Response of the Brain Under Blast: The Effect of Blast Direction and the Head Protection
Authors: Sarvghad-Moghaddam Hesam , Rezaei Asghar , Eslaminejad Ashkan , Ziejewski Mariusz , Karami Ghodrat
Published: February 2017

Blast-induced traumatic brain injury (bTBI), is defined as a type of acquired brain injury that occurs upon the interaction of the human head with blast-generated high-pressure shockwaves. Lack of experimental studies due to moral issues, have motivated the researchers to employ computational methods to study the bTBI mechanisms. Accordingly, a nonlinear finite element (FE) analysis was employed to study the interaction of both unprotected and protected head models with explosion pressure waves. The head was exposed to the incoming shockwaves from front, back, and side directions. The main goal was to examine the effects of head protection tools and the direction of blast waves on the tissue and kinematical responses of the brain. Generation, propagation, and interactions of blast waves with the head were modeled using an arbitrary Lagrangian-Eulerian (ALE) method and a fluid-structure interaction (FSI) coupling algorithm. The FE simulations were performed using Ls-Dyna, a transient, nonlinear FE code. Side blast predicted the highest mechanical responses for the brain. Moreover, the protection assemblies showed to significantly alter the blast flow mechanics. Use of faceshield was also observed to be highly effective in the front blast due to hindering of shockwaves.
Shear Lag Sutures: Improved Suture Repair Through the Use of Adhesives
Authors: Linderman Stephen W. , Kormpakis Ioannis , Gelberman Richard H. , Birman Victor , Wegst Ulrike G. K. , Thomopoulos Stavros , Genin Guy M.
Published: February 2017

Conventional surgical suture is mechanically limited by the ability of the suture to transfer load to tissue at suture anchor points. Sutures coated with adhesives can improve mechanical load transfer beyond the range of performance of existing suture methods, thereby strengthening orthopaedic repairs and decreasing the risk of failure. The mechanical properties of suitable adhesives were identified using a shear lag model. Examination of the design space for an optimal adhesive demonstrated requirements for strong adhesion and low stiffness to maximize strength. As a proof of concept, cyanoacrylate-coated sutures were used to perform a clinically relevant flexor digitorum profundus tendon repair in cadaver tissue. Even with this non-ideal adhesive, the maximum load resisted by repaired cadaveric canine flexor tendon increased by ∼ 17.0% compared to standard repairs without adhesive. To rapidly assess adhesive binding to tendon, we additionally developed a lap shear test method using bovine deep digital flexor tendons as the adherends. Further study is needed to develop a strongly adherent, compliant adhesive within the optimal design space described by the model.
Computational Micromechanics of Trabecular Porcine Skull Bone Using the Material Point Method
Authors: Fang Ziwen , Ranslow Allison N. , Kraft Reuben H.
Published: February 2017

The trabecular bone in the porcine skull is geometrically complex. It can be characterized experimentally, but requires many test configurations, loading rates, and samples to develop trusted constitutive models that fully characterize the complexity. Typically, Lagrangian finite element simulations are used in the bone modeling community to replicate experimental results for model validation and determination of material properties. In this approach, microCT images are used to develop anatomically accurate surfaces that are then volume meshed. While this modeling approach is valuable, there are some limitations. For example, with high-resolution micoCT data, traditional meshing techniques have proven to be insufficient. Specifically with highly porous trabecular bone data, the complexity of the pore architecture is difficult to be replicated by finite element mesh. To overcome this challenge, the application of material point method (MPM) has been investigated for analyzing the material properties of trabecular bone. This meshless method requires a “particle mesh” that can be derived directly from the microCT data. This process is much easier than developing a finite element mesh. Preliminary results have focused on generating the stress-strain curves for quasi-static loading and comparing numerical predictions with experimental results, as well as verifying the MPM against the finite element method. Initial results are promising and we have seen good comparison with experimental results. Parallel scalability of MPM has also been assessed since large-scale simulations can be expected for the future research.
Validation of Embedded Element Method in the Prediction of White Matter Disruption in Concussions
Authors: Garimella Harsha T. , Kraft Reuben H.
Published: February 2017

A better understanding of the axonal injury would help us develop improved diagnostic tools, protective measures, and rehabilitation treatments. Computational modeling coupled with advanced neuroimaging techniques might be a promising tool for this purpose. However, before the models can be used for real life applications, they need to be validated and cross-verified with real life scenarios to establish the credibility of the model. In this work, progress has been made in validating a human head finite element model with embedded axonal fiber tractography (using embedded element method) using pre- and post-diffusion tensor imaging data (DTI) of a concussed athlete. Fractional anisotropy (FA) was used to determine the microstructural changes during injury. These damaged locations correlated well with the damaged locations observed from the finite element model. This work could be characterized as a first step towards the development of a more comprehensively validated human head finite element model.
Stability and Collapsing Mechanism of Cavitation-Induced Nanobubbles in Simulated Extra-Cellular Matrix (ECM) Near Neuron
Authors: Wu Y.-T. , Adnan A.
Published: February 2017

In blast-induced traumatic brain injury, shock waves (SW) play an important role along with cavitation phenomena. Due to the lack of reliable and reproducible experimental investigations, we have a limited understanding of the role of cavitation in brain damage. The present study aims to develop an atomistic simulation model to determine the role of shock-induced impulse and different constituents of the brain’s extra-cellular matrix (ECM) on the formation mechanism, stability and collapsing mechanism of nanobubbles in the ECM. The ECM in the brain can be divided into three major types depending on their location behind the blood-brain barrier, namely (a) the basement membrane (basal lamina), (b) the perineuronal nets and (3) the neural interstitial matrix. In this paper, we have studied the interaction of nanobubbles with bio-molecules of the perineuronal nets. We have chosen this zone of the ECM because we are interested to obtain the role of cavitation bubble collapse in neuron damage. Most biomolecules of perineuronal nets are slender in shape and flexible which is believed to induce special solid-fluid interaction between the fluid domain and the solid domain within the ECM. In addition, perineuronal nets contain a significant number of sodium ions. The relationship between sodium ion and solid-like constituents of perineuronal nets on the stability and the collapsing mechanism of nanobubbles will be discussed.
Thermal Shock Buckling of a Functionally Graded Circular Plate
Authors: Zhang Jinghua , Zhao Xingxing
Published: February 2017

The dynamic buckling of a functionally graded material (FGM) circular plate subjected to thermal shock is studied in the Hamilton system. It is assumed that the lower surface of the circular plate is subjected to uniform thermal shock. Considering the one-dimensional heat conduction problem and basing on theory of Fourier heat conduction, the dynamic temperature fields of the FGM circular plate under thermal shock are obtained. The dynamic buckling problem of the FGM circular plate is finally reduced to zero-eigenvalue problem in the symplectic space. The critical loads and buckling modes of the functionally graded circular plate correspond to generalized eigenvalue and eigen solution, and can be obtained through bifurcation condition. In this study, the buckling characteristics of the FGM plate subjected to thermal shock are solved by symplectic method, and the solution process is given. The effects of the material constitution, structural geometric parameters and thermal shock load on the critical temperature are discussed.
Field Improvised Electric Arc Welder
Authors: Geiser Kyle , Maier William , Ives Nicholas , Van Curen Jared , Tamm Gunnar , Hoyer Brodie , Moore Harry
Published: February 2017

Generations of warfighters have benefited from field manuals to provide instructional knowledge for creating improvised devices and capabilities from readily available resources. These devices range from simple fundamentals to classified advances in materials and technologies. A collaborative effort between the United States Military Academy and the U.S. Army Armament Research, Development and Engineering Center is creating the latest repertoire of capabilities for soldiers in theater. An improvised electric arc welder was developed to provide field expedient capabilities to them. Both AC wall power and DC power from car batteries were utilized to demonstrate various options. This paper provides the electrical models, experimental results and lessons learned. Welds were tested in a tension tester to determine their viability.
Analyzing the Effect of Workpiece Stiffness Variation on the Stability in Flank Milling of an Impeller Blade
Authors: Singh Narendra , Agrawal Ankita , Wanaskar Kapil , Kartik V. , Joshi Suhas S.
Published: February 2017

While the blade like components of uniform thickness have been investigated for their stability in machining, impeller blade like components with varying thickness along the length and with varying width along the height have received little attention so far. Therefore, this work focuses on analyzing the effect of variation in workpiece flexibility, stiffness and rigidity on the stability of flank milling operation on impeller blade like component. Extensive experimentation was done on work specimens of (i) varying thickness along length and (ii) varying width along height. Cutting forces, acceleration and deflection of tool and work specimens were captured during all the experiments through FFT plots, chatter boundary plots followed by the stability region diagrams. The cutting force data was acquired in time domain at five different locations under varying conditions of spindle speeds and depths of cut, and were the main inputs for plotting stability region diagram. The consolidated stability region diagram shows that the stable machining, baring the few chatter peaks of low frequency and magnitude, is possible at the feed rate of 240 mm/min. and depth of cut of 1.5 mm, when the thickness as well as the width variations in the impeller blade like specimens are considered.
Analytical Model of Progression of Flank Wear Land Width in Drilling
Authors: Das Ranjan , Joshi Suhas S. , Barshilia Harish C.
Published: February 2017

In multi-point operations like drilling, cutting velocities and cutting edge geometries vary along cutting lips so is the rate of progression of flank wear. Analytical evaluation of flank wear land width in the case of complex tools has received a limited attention so far. This work evaluates progression of flank wear in orthogonal machining and adopts it to drilling. An abrasive flank wear has been modeled, wherein, cutting speed determines the rate of abrasion, and the feed rate determines the chip load. The model considers stress distribution along rake surfaces, and temperature dependent properties of tool and work materials. Assuming that the flank wear follows a typical wear progression as in a pin-on-disc test, the model evaluates cutting forces and the consequent abrasive wear rate for an orthogonal cutting. To adopt it to drilling, variation in cutting velocity and, dynamic variation in rake, shear and friction angles along the length of the cutting lips have been considered. Knowing the wear rate, the length of the worn out flank (VB) has been evaluated. The model captures progression of flank wear in zones I, II and III of a typical tool life plot. It marginally underestimates the wear in the rapid wear region and marginally overestimates it in the steady-state region.
Study on the Effect of Weld Speed and Tool Rotation Speed on the Quality of Friction Stir Welded Joints by Using XRD and EBSD
Authors: Sanjeevi Maran Jaishree , Patro Pratyush Kumar , Murugesan Ilangovan , Sekar Sai Krishna , Bamarani Thangaswamy Sidhaarth
Published: February 2017

Friction Stir processing, a novel welding process which weld similar and dissimilar metals and alloys in solid state for joining metallic alloys and it has replaced conventional welding processes and have become an alternative welding technique. The commonly used aluminum alloys AA6061 and AA5086 were joined together using FSW. In this study, two parameters such as weld speed and tool rotation speed are taken into account. By varying these parameters the dissimilar alloys were welded together. The welded joints were analyzed for its chemical composition and phases formed due to heat produced by friction. The composition is characterized by Electron Back Scattered Diffraction technique (EBSD) and X-ray Diffraction technique (XRD). The influence of tool rotation speed and weld speed on texture has been studied.
A Sensitivity Study of the Porcine Head Subjected to Bump Impact
Authors: Thompson Kimberly A. , Sokolow Adam C. , Ivancik Juliana , Zhang Timothy G. , Mermagen William H. , Satapathy Sikhanda S.
Published: February 2017

Understanding load transfer to the human brain is a complex problem that has been a key subject of recent investigations [4–6]. Because the porcine is a gyrencephalic species, having greater structural and functional similarities to the human brain than other lower species outlined in the literature, it is commonly chosen as a surrogate for human brain studies [7]. Consequently, we have chosen to use a porcine model in this work. To understand stress wave transfer to and through the brain, it is important to fully characterize the nature of the impact (i.e. source, location, and speed) as well as the response of the constituent tissues under such impact. We suspect the material and topology of these tissues play an important role in their response.

In this paper, we report on a numerical study assessing the sensitivity of model parameters for a 6-month old Gottingen mini-pig model, under bump loading. In this study, 2D models are used for computational simplicity. While a 3D model is more realistic in nature, a 2D representation is still valuable in that it can provide trends on parameter sensitivity that can help steer the development of the 3D model. In this work, we investigate the variation of skull and skin thickness, evaluate material variability of the skull, and consider the effects of nasal cavities on load transfer. Eighty simulations are computed in LS-DYNA and analyzed in MATLAB. The results of this study will provide useful knowledge on the necessary components and parameters of the porcine model and therefore provide more confidence in the analysis. This is an essential first step as we look toward bridging the gap between correlates of injury in animal and human models.
Fabrication of germanium nanodisk array by neutral beam etching with protein as etching mask
Authors: Fujii Takuya , Okada Takeru , Isoda Taiga , Syazwan Mohd Erman , Chentir Mohamed-Tahar , Itoh Kohei M. , Yamashita Ichiro , Samukawa Seiji
Published: February 2017

A uniform 10 nm diameter Ge two-dimensional (2D) nanodisk array structure was fabricated using iron oxide cores in a 2D closed-packed array of cage shaped proteins, ferritins, as an etching mask. Thin Ge layer on Si substrate was protected by a-Si capping layer and etched, which eliminated an uncontrollable factor of Ge native oxide. The density of Ge nanodisks was as high as 5.8 × 1011 cm−2, and the center-to-center distance was estimated to be 14 nm. It was demonstrated that a quantum confinement effect can be obtained with our fabricated Ge nanodisk array by controlling the nanodisk thickness. The obtained high density Ge nanodisk is promising for Ge/Si quantum dot intermediate band solar cells and other photonics devices.
Language-independent talker-specificity in first-language and second-language speech production by bilingual talkers: L1 speaking rate predicts L2 speaking rate
Authors: Bradlow Ann R. , Kim Midam , Blasingame Michael
Published: February 2017

Second-language (L2) speech is consistently slower than first-language (L1) speech, and L1 speaking rate varies within- and across-talkers depending on many individual, situational, linguistic, and sociolinguistic factors. It is asked whether speaking rate is also determined by a language-independent talker-specific trait such that, across a group of bilinguals, L1 speaking rate significantly predicts L2 speaking rate. Two measurements of speaking rate were automatically extracted from recordings of read and spontaneous speech by English monolinguals (n = 27) and bilinguals from ten L1 backgrounds (n = 86): speech rate (syllables/second), and articulation rate (syllables/second excluding silent pauses). Replicating prior work, L2 speaking rates were significantly slower than L1 speaking rates both across-groups (monolinguals' L1 English vs bilinguals' L2 English), and across L1 and L2 within bilinguals. Critically, within the bilingual group, L1 speaking rate significantly predicted L2 speaking rate, suggesting that a significant portion of inter-talker variation in L2 speech is derived from inter-talker variation in L1 speech, and that individual variability in L2 spoken language production may be best understood within the context of individual variability in L1 spoken language production.
The role of interaural differences on speech intelligibility in complex multi-talker environments
Authors: Ellinger Rachel L. , Jakien Kasey M. , Gallun Frederick J.
Published: February 2017

Interaural differences in time (ITDs) and interaural differences in level (ILDs) contribute to a listener's ability to achieve spatial release from masking (SRM), and help to improve speech intelligibility in noisy environments. In this study, the extent to which ITDs and ILDs contribute to SRM and the relationships with aging and hearing loss were examined. SRM was greatest when stimuli were presented with consistent ITD and ILD, relative to ITD or ILD alone, all of which produced greater SRM than when ITD and ILD cues were in conflict with each other. This pattern was independent of age and hearing loss.
Failed spinal cord trial offers cautionary tale
Authors: Servick Kelly
Published: February 2017

Collaborators contend clinical stem cell lines lacked support from animal studies.
The Birth of CRISPR Inc
Authors: Cohen Jon
Published: February 2017

How a community fractured as a revolutionary genome-editing tool became a business.
Host cell attachment elicits posttranscriptional regulation in infecting enteropathogenic bacteria
Authors: Katsowich Naama , Elbaz Netanel , Pal Ritesh Ranjan , Mills Erez , Kobi Simi , Kahan Tamar , Rosenshine Ilan
Published: February 2017

Touchdown for gut pathogen virulence

Escherichia coli
is transformed from a commensal organism into a pathogen by acquisition of genetic elements called pathogenicity islands (PAIs). Katsowich
et al.
investigated how the PAI virulence genes of enteropathogenic
E. coli
(EPEC) respond when the bacterium attaches to a host gut cell. EPEC first sticks to the host by means of pili and then uses a PAI-encoded type 3 secretion system (T3SS) to inject multiple effectors into the host cell. But not all virulence mediators are injected. For example, CesT, a bacterial chaperone, delivers virulence effectors into the T3SS apparatus. Then, within the bacterial cytoplasm, it interacts with a gene repressor called CsrA, which reprograms bacterial gene expression to help the bacteria to adapt to epithelial cell–associated life.

Science
, this issue p.
735
Treadmilling by FtsZ filaments drives peptidoglycan synthesis and bacterial cell division
Authors: Bisson-Filho Alexandre W. , Hsu Yen-Pang , Squyres Georgia R. , Kuru Erkin , Wu Fabai , Jukes Calum , Sun Yingjie , Dekker Cees , Holden Seamus , VanNieuwenhze Michael S. , Brun Yves V. , Garner Ethan C.
Published: February 2017

Coordinating cell wall synthesis and cell division

Most bacteria are protected by peptidoglycan cell walls, which must be remodeled to split the cell. Cell division requires the tubulin homolog FtsZ, a highly conserved cytoskeletal polymer that specifies the future site of division. Bisson-Filho
et al.
and Yang
et al.
found that the dynamic treadmilling of FtsZ filaments controls both the location and activity of the associated cell wall synthetic enzymes. This creates discrete sites of cell wall synthesis that circle around the division plane to divide the cell.

Science
, this issue p.
739
, p.
744
Fighting the enemy within
Authors: Tacconelli Evelina , Autenrieth Ingo B. , Peschel Andreas
Published: February 2017

Halting the rise in antibiotic-resistant infections requires drugs that selectively target pathogens in microbiota
Clonal Complexity in Mycobacterium tuberculosis Can Hamper Diagnostic Procedures
Authors: Pérez-Lago Laura , Herranz Marta , Navarro Yurena , Ruiz Serrano María Jesús , Miralles Pilar , Bouza Emilio , García-de-Viedma Darío
Published: February 2017

Clonal complexity is increasingly accepted inMycobacterium tuberculosisinfection, including mixed infections by ≥2 strains, which usually occur in settings with a high burden of tuberculosis and/or a high risk of overexposure to infected patients. Mixed infections can hamper diagnostic procedures; obtaining an accurate antibiogram is difficult when the susceptibility patterns of the strains differ. Here, we show how mixed infections can also prove challenging for other diagnostic procedures, even outside settings where mixed infections are traditionally expected. We show how an unnoticed mixed infection in an HIV-positive patient diagnosed in Madrid, Spain, with differences in the representativeness of the coinfecting strains in different sputum samples, markedly complicated the resolution of a laboratory cross-contamination false positivity alert.
Establishment and Use of Epidemiological Cutoff Values for Molds and Yeasts by Use of the Clinical and Laboratory Standards Institute M57 Standard
Authors: Lockhart Shawn R. , Ghannoum Mahmoud A. , Alexander Barbara D.
Published: February 2017

Breakpoints are used to predict whether an antifungal agent will be clinically effective against a particular fungal isolate. They are based on a combination of MIC values, pharmacokinetic/pharmacodynamic values, and clinical outcome data. For many fungus-antifungal combinations, these data might never be available. For these combinations, epidemiological cutoff values (ECVs) provide a methodology for categorizing isolates as either wild type (WT) or non-WT. In this review, we define ECVs, explain how they are generated using the CLSI methodology in standard M57, and describe how they can be used in clinical practice.
The Long Noncoding RNA NEAT1 Exerts Antihantaviral Effects by Acting as Positive Feedback for RIG-I Signaling
Authors: Ma Hongwei , Han Peijun , Ye Wei , Chen Hesong , Zheng Xuyang , Cheng Linfeng , Zhang Liang , Yu Lan , Wu Xing'an , Xu Zhikai , Lei Yingfeng , Zhang Fanglin
Published: February 2017

Hantavirus infection, which causes zoonotic diseases with a high mortality rate in humans, has long been a global public health concern. Over the past decades, accumulating evidence suggests that long noncoding RNAs (lncRNAs) play key regulatory roles in innate immunity. However, the involvement of host lncRNAs in hantaviral control remains uncharacterized. In this study, we identified the lncRNA NEAT1 as a vital antiviral modulator. NEAT1 was dramatically upregulated after Hantaan virus (HTNV) infection, whereas its downregulation
in vitro
or
in vivo
delayed host innate immune responses and aggravated HTNV replication. Ectopic expression of NEAT1 enhanced beta interferon (IFN-β) production and suppressed HTNV infection. Further investigation suggested that NEAT1 served as positive feedback for RIG-I signaling. HTNV infection activated NEAT1 transcription through the RIG-I–IRF7 pathway, whereas NEAT1 removed the transcriptional inhibitory effects of the splicing factor proline- and glutamine-rich protein (SFPQ) by relocating SFPQ to paraspeckles, thus promoting the expression of RIG-I and DDX60. RIG-I and DDX60 had synergic effects on IFN production. Taken together, our findings demonstrate that NEAT1 modulates the innate immune response against HTNV infection, providing another layer of information about the role of lncRNAs in controlling viral infections.

IMPORTANCE
Hantaviruses have attracted worldwide attention as archetypal emerging pathogens. Recently, increasing evidence has highlighted long noncoding RNAs (lncRNAs) as key regulators of innate immunity; however, their roles in hantavirus infection remain unknown. In the present work, a new unexplored function of lncRNA NEAT1 in controlling HTNV replication was found. NEAT1 promoted interferon (IFN) responses by acting as positive feedback for RIG-I signaling. This lncRNA was induced by HTNV through the RIG-I–IRF7 pathway in a time- and dose-dependent manner and promoted HTNV-induced IFN production by facilitating RIG-I and DDX60 expression. Intriguingly, NEAT1 relocated SFPQ and formed paraspeckles after HTNV infection, which might reverse inhibitive effects of SFPQ on the transcription of RIG-I and DDX60. To the best of our knowledge, this is the first study to address the regulatory role of the lncRNA NEAT1 in host innate immunity after HTNV infection. In summary, our findings provide additional insights regarding the role of lncRNAs in controlling viral infections.
Musculoskeletal dysfunctions associated with swimmers’ shoulder
Authors: Struyf Filip , Tate Angela , Kuppens Kevin , Feijen Stef , Michener Lori A
Published: February 2017

Shoulder pain is the most reported area of orthopaedic injury in swimmers. The so-called ‘swimmers’ shoulder’ has been applied to a variety of complaints involving shoulder pain in swimmers without specific reference to contributing mechanisms or structures. Knowledge of dysfunctions associated with swimmers’ shoulder can assist clinicians in developing rehabilitation strategies. This literature review aims at providing clinicians insight into the musculoskeletal mechanisms and impairments associated with swimmers’ shoulder that could aid them in developing rehabilitation strategies. The following musculoskeletal dysfunctions will be discussed: muscle activity, strength, endurance, muscle control, range of motion, glenohumeral laxity, glenohumeral instability, shoulder posture and scapular dyskinesis. The findings in this review may have implications for swimmers, their coaches, and rehabilitation specialists working with swimmers.