bluuebunny/crossref_metadata_2025 huggingface dataset:
Step Ring Based 3D Path Planning via GPU Simulation for Subtractive 3D Printing
Authors: Wu Zhengkai , Tucker Thomas M. , Nath Chandra , Kurfess Thomas R. , Vuduc Richard W.
Published: September 2016

In this paper, both software model visualization with path simulation and associated machining product are produced based on the step ring based 3-axis path planning to demo model-driven graphics processing unit (GPU) feature in tool path planning and 3D image model classification by GPU simulation. Subtractive 3D printing (i.e., 3D machining) is represented as integration between 3D printing modeling and CNC machining via GPU simulated software. Path planning is applied through material surface removal visualization in high resolution and 3D path simulation via ring selective path planning based on accessibility of path through pattern selection. First, the step ring selects critical features to reconstruct computer aided design (CAD) design model as STL (stereolithography) voxel, and then local optimization is attained within interested ring area for time and energy saving of GPU volume generation as compared to global all automatic path planning with longer latency. The reconstructed CAD model comes from an original sample (GATech buzz) with 2D image information. CAD model for optimization and validation is adopted to sustain manufacturing reproduction based on system simulation feedback. To avoid collision with the produced path from retraction path, we pick adaptive ring path generation and prediction in each planning iteration, which may also minimize material removal. Moreover, we did partition analysis and g-code optimization for large scale model and high density volume data. Image classification and grid analysis based on adaptive 3D tree depth are proposed for multi-level set partition of the model to define no cutting zones. After that, accessibility map is computed based on accessibility space for rotational angular space of path orientation to compare step ring based pass planning verses global all path planning. Feature analysis via central processing unit (CPU) or GPU processor for GPU map computation contributes to high performance computing and cloud computing potential through parallel computing application of subtractive 3D printing in the future.
Optimizing Origami-Based Sheet Metal Parts Using Traversal Algorithms and Manufacturing Based Indices
Authors: Qattawi Ala
Published: September 2016

Origami-based sheet metal (OSM) folding techniques is a new emerging manufacturing procedure for sheet metal. In OSM the final part is folded into the desired 3D geometry using a sequence of folded bend lines. This process is enabled by creating material discontinues along the bend lines, either by laser cutting or by stamping. The objective of this paper is to optimize the design of OSM products while accounting for all possible flat patterns and accommodate manufacturing requirements for sheet metal products. OSM has an anticipated manufacturing benefits compared to traditional processes of sheet metal such as stamping; it requires minimal tooling and energy requirements thus is suitable for sustainable manufacturing alternatives. This paper discusses the implementation of optimization technique for OSM parts using a combination of traversal algorithm and manufacturing based indexes to reflect the requirements present in sheet metal industry. The outcomes of the optimization procedure resulted with topologically valid flat patterns with minimal scrap and wasted materials, in addition to minimal number of welded lines and fold line orientations in case of a robot effector is used to perform the fold. The work presented in this paper verified the validity of folding sheet metal using a single flat pattern into complex 3-D geometries from topological point view, in addition it highlights the major manufacturing concerns in folding sheet metal. This work also demonstrates a case study of optimizing a vehicular OSM part developed method.
Tool Posture and Polishing Force Control on Unknown 3-Dimensional Curved Surface
Authors: Oba Yuta , Kakinuma Yasuhiro
Published: September 2016

In the painting process in automotive manufacturing, the repair polishing process is still done manually by a worker with a sufficient skilled technique. However, the number of skilled workers is decreasing with the aging. In addition, the polishing time and the surface quality after the repair polishing are dependent on the proficiency level of the worker. Thus, skill-independent automation technology for the repair polishing is required. In our past research, the serial-parallel mechanism polishing machine was developed for automating the polishing process. The developed machine can control the tool trajectory, tool posture and polishing force simultaneously. In addition, the polishing force is controlled without external sensors by the reaction force observer system. This study aims to develop a polishing automation method for unknown 3-dimensional curved surface by using the developed machine. First, the tool posture control method on unknown curved surface was proposed. Second, the normal force control method based on the posture information was proposed. By using these proposed methods simultaneously, the tool posture and polishing force were controlled in the normal direction on unknown 3-dimesional curved surface. From the experimental results, the validity of the proposed method was verified.
Analysis on the Effects of Grinding Wheel Speed on Removal Behavior of Brittle Optical Materials
Authors: Li Ping , Jin Tan , Guo Zongfu , Yi Jun , Qu Meina
Published: September 2016

It is often desired to increase the machining rate while maintaining the desired surface and subsurface integrity during fabricating high-quality optical glass components. This paper proposed a high-speed high-efficiency low-damage grinding technology for machining brittle optical materials, which consists of three grinding processes: rough grinding, semi-finishing grinding and finishing grinding. Grinding characteristics is investigated with respect to grinding forces, specific cutting energy, surface roughness, ground surface quality, subsurface damage, and material removal mechanisms in grinding of fused silica optical glasses with this technology at the grinding speeds of up to 150 m/s. These indications are thoroughly discussed by contacting the undeformed chip thickness. The results indicate that the level of these indications are significantly improved with an increase in the wheel speed due to the decrease of the undeformed chip thickness. It is also found that the improvement of ground surface quality is limited when the wheel speed from 120 m/s increases to 150 m/s may be due to the influence of vibration caused by the higher wheel speed. For different grinding processes, these results are also substantially improved with the change of grinding conditions. It is found that the material removal mechanism is dominated by brittle fracture at rough and semi-finishing grinding processes, while ductile flow mode can be observed at the finishing grinding process. There are some differences between the experimental results and the previous predicted model of subsurface damage depth.
Polishing Characteristics of Transparent Polycrystalline YAG Ceramics Using Magnetic Field-Assisted Finishing
Authors: Ross Daniel , Wang Yanming , Ramadhan Hadyan , Yamaguchi Hitomi
Published: September 2016

Transparent polycrystalline yttrium aluminum garnet (YAG) ceramics have garnered an increased level of interest for high-power laser applications due to their ability to be manufactured in large sizes, and doped in relatively substantial concentrations when compared to traditional single-crystalline gain media. However, surface characteristics have a direct effect on the lasing ability of these materials, and a lack of a fundamental understanding of the polishing mechanisms of these ceramics remains a challenge for their utilization. The aim of this paper is to study the polishing characteristics of YAG ceramics using magnetic field-assisted finishing (MAF). An experimental setup was developed, through the refinement of the MAF process, for YAG ceramic workpieces. Using this equipment with diamond abrasives, the YAG ceramic surfaces were polished to sub-nanometer scale. Polishing trials with fine diamond abrasive and colloidal silica were then performed on this sub-nanometer surface and the material removal mechanisms were analyzed.

Polishing with 0–0.1 μm diameter diamond abrasive caused increasing roughness with polishing time due to the continuous cycle of relatively substantial chipping followed by minor smoothing. Polishing with colloidal silica caused valleys to widen with increased polishing time and the grain structure of the ceramic influenced the material removal.
Experimental Study of Chemo-Thermal Micromachining of Glass
Authors: Ali Arham , Sundaram Murali
Published: September 2016

Chemo-thermal micro-machining is a hybrid method of micro fabrication achieved by integrating laser based thermal ablation and chemical etching. Material removal in this process involves focussing laser beam on a glass specimen submerged in aqueous sodium hydroxide (NaOH) solution that causes chemical degradation of glass along with thermal ablation at the laser target point. Though laser by itself is capable of machining numerous materials, it often causes micro fractures radially along the machined surface, especially when used on glass. In the proposed process, continuous waves of carbon dioxide laser (10.6 μm wavelength) with varying power are irradiated on the surface of borosilicate glass slide immersed in 1M NaOH solution for varying duration of exposure. This resulted in smaller hole diameter and better surface finish in the micro machining of glass, as compared to machining by laser beam alone.
Towards Resolution Enhancement and Process Repeatability With a Melt Electrospinning Writing Process: Design and Protocol Considerations
Authors: Tourlomousis Filippos , Ding Houzhu , Dole Antonio , Chang Robert C.
Published: September 2016

With recent advancements in the direct electrostatic printing of highly viscous thermoplastic polymers onto an automated collector, melt electrospinning writing technology (MEW) has shown great potential for addressing the fundamental effects of an engineered scaffold’s dimensional parameters (e.g. fiber diameter, apparent pore size, and pore shape) on cultured cell–scaffold interactions. The superior resolution obtainable with MEW compared to conventional extrusion-based 3D printing technologies and its ability for toolpath-controlled fiber printing can facilitate the creation of a complex cell microenvironment or niche. Such a cell niche would provide the microscale fiber diameter and pore size for a scaffold substrate to present dimensional cues that affect downstream cellular function. In this study, the authors present in detail the design of a custom MEW system that allows simultaneous thermal management in the material, spin-line, and collector regimes using a heat gun. The complex interplay of process and instrument-based parameters is clarified with respect to stable jet formation allowing the printing of scaffolds with various microstructural patterned cues and consistent fiber diameter in a reproducible manner. Current fabrication of high fidelity scaffolds requires that the ratio of inter-fiber distance to fiber diameter to be an approximate value of 10. Since this manufacturing challenge yields pore sizes that are prohibitively large for 3D cell culture studies, particular emphasis is given in this paper to address the underlying physical mechanisms that will enable the fabrication of pore sizes with MEW scaffolds at cellular-relevant fiber diameters (10 – 50 μm). The authors show that appropriate toolpath planning that takes into account the different modes of the process can improve the inter-fiber distance resolution and thus the scaffold’s apparent pore size.
Broaching Tool Degradation Characterization Based on Functional Descriptors
Authors: Tian Wenmeng , Wells Lee J. , Camelio Jaime A.
Published: September 2016

With rapid advancements in sensing technologies and computation capabilities, high-resolution machine vision data have become available for various manufacturing processes. For machining, the use of machine vision data has shown great promise in machining tool condition monitoring, a critical factor for final product quality. Extensive research has been performed on wear characterization using intensity-based methods, but limited work has made use of process knowledge for image processing phases. Additionally, previous work focuses on single cutting edge machining tools, but no methods have been proposed for multiple cutting edge machining tools, such as broaches. In this paper, a process knowledge-based image filtering method is proposed to eliminate within-image and between-image noise to obtain effective wear region(s) for each cutting edge on a broach. In addition, these wear regions across multiple cutting edges are jointly described by fitting their relationship with each cutting edge’s respective chip load. Finally, the extracted model parameters are used for unsupervised learning to determine the entire tool’s degradation levels from a training dataset. A case study is introduced to show the effectiveness of the proposed methodology using a hexagonal broach.
Artificial Neural Network Based Geometric Compensation for Thermal Deformation in Additive Manufacturing Processes
Authors: Chowdhury Sushmit , Anand Sam
Published: September 2016

Additive manufacturing (AM) processes involve the fabrication of parts in a layer-wise manner. The layers of material are deposited using a variety of established methodologies, the most popular of which involve either the use of a powerful laser to sinter/melt successive layers of metal/alloy/polymer powders or, the deposition of layers of polymers through a heated extrusion head at a controlled rate. The thermal nature of these processes causes the development of temperature gradients throughout the part and as a result, the part undergoes irregular deformations which ultimately leads to dimensional inaccuracies in the manufactured part. An Artificial Neural Network (ANN) based methodology is presented in this paper to directly compensate the part geometric design which will help to counter the thermal deformations in the manufactured part. A feed-forward ANN model is trained using backpropagation algorithm to study part deformations resulting from the AM process. The trained network is subsequently employed on the part Stereolithography (STL) file to effect the required geometrical corrections. Two examples are presented to evaluate the performance of the proposed compensation methodology. A novel approach to evaluate the conformity of the final part profile to the original part CAD profile has also been developed to quantify the performance of the proposed methodology. The results of the examples show substantial improvement in the part accuracy and thus validate the ANN based geometric compensation approach.
Composability of Unit Manufacturing Process Models for Manufacturing Systems Analysis
Authors: Smullin Matteo M. , Garretson Ian C. , Haapala Karl R.
Published: September 2016

Manufacturing accounts for 31% of all energy consumed in the United States. Of increasing concern to industry decision makers is how to make their manufacturing processes more sustainable. Current sustainable assessment methods do not consider the parameters of unit manufacturing processes (UMPs) and, thus, do not provide the granular level of modeling required for accurate sustainability performance assessment. Further, there is little research within the field of sustainable manufacturing into how to recompose UMPs to form a unified model of a manufacturing system. This research attempts to rectify this deficiency by investigating the feasibility of composing (linking) disparate processes by incorporating the workpiece as an information repository. This enables modeling the information flows between processes as a co-product of the transformations imparted to the workpiece by the selected manufacturing processes. The result is a method for assessing the sustainability performance of a manufacturing system. This method would provide value to decision makers through more capable tools to better understand the sustainability performance of their manufacturing system.
Springback Induced in Single Point Incrementally Formed 2024-T3 Aluminum of Various Thicknesses
Authors: Neveux Trey C. , Roth John T. , Ragai Ihab
Published: September 2016

Incremental forming (IF) is sheet metal process proving to be of particular interest in industry as a method to create complex geometries. The technology offers the flexibility to create complex geometry on drafted profiles without the necessity of a forming die, which offers unique advantages over die forming processes, including: significantly reduced lead time, eliminating initial die costs and the need to retain the die after the products life cycle is complete, which can be significant, and the ability to modify the geometry with relative ease throughout the product’s life cycle.

During incremental forming, the material’s local plastic deformation induces high residual stresses into the workpiece, causing significant springback once it is released from the clamping fixture used to hold the workpiece stationary during forming. Different material thicknesses result in different degrees of springback on the workpiece. This is due in part to the change in section modulus of the formed part. Thicker materials will have a larger section modulus and therefore not be if two different material thicknesses undergo equal deformation, the thinner material will experience greater elastic recovery, or springback.

If incremental forming is to ever reach industry level applications, the material’s springback behavior at a variety of thicknesses must be characterized. Having the knowledge of the resulting springback is necessary for further research to be conducted on incremental forming in order to reduce or eliminate springback. Also, it is important for designers and engineers to design products within the capabilities of the technique.

This paper investigates the springback present in 5 thicknesses of 2024-T3 clad aluminum subsequent to incremental forming and release from the forming fixture.

It is found that as material sheet thickness increases and the specimens are formed to the same internal geometries, springback after releasing from the clamping fixture decreases, and variation in springback between equal thicknesses decreases.
Manufacturing of Anatomically Accurate Cerebral Arteries for the Brain Aneurysm Surgical Simulator
Authors: Price Alexander , Savastano Luis , Lin Wei-Chen , Belmont Barry , Shih Albert
Published: September 2016

Here we present the design and manufacture of a simulated middle cerebral artery for neurosurgeons to practice brain aneurysm surgical procedures. The middle cerebral artery made of silicone is hollow with anatomically accurate features (including the aneurysm) based on the patient geometry found via computed tomography. A five-step fabrication technique was developed to (1) 3D-print the positive shape of the middle cerebral artery, (2) submerge the vessel in silicone to create a mold of the negative shape of the vessel, (3) fill the silicone mold with low melting temperature metal to create a positive cast of the vessel, (4) coat the investment with silicone, and (5) remove the metal with hot water to create the hollow middle cerebral artery. This vessel has been evaluated by neurosurgeons and demonstrated to be feasible for brain aneurysm clinical simulations.
Laser Engineered Net Shaping of Commercially Pure Titanium: Effects of Fabricating Variables
Authors: Hu Yingbin , Wang Hui , Ning Fuda , Cong Weilong
Published: September 2016

Commercially pure titanium (CP-Ti) attracts a large number of attentions in biomedical, astronautical, and auto industrial areas due to its superior properties of good biocompatibility, excellent corrosion resistance, and high strength-to-weight ratio. Comparing with the conventional manufacturing processes (such as casting along with machining), laser additive manufacturing (LAM), mainly including selective laser sintering/melting (SLS/M) and laser engineered net shaping (LENS), has many advantages, such as complex shaped parts producing, more capability of shorter design-to-market time, energy consumption reducing, etc. It was reported that SLS/M has been successfully used in fabricating of CP-Ti components. Comparing with SLS/M processes, LENS has many advantages, including lower labor intensity, higher fabrication efficiency, and more capabilities for parts repairing and rebuilding. It is reported that LENS process was only used in CP-Ti coating and porous parts fabrication, there are no reported investigations on CP-Ti three-dimensional (3D) solid parts using LENS process. The investigations in this paper are going to conduct preliminary studies on effect of fabricating variables. In order to evaluate powder efficiency and parts’ quality, heights of fabricated parts and hardness on the top surface of the parts will be tested.
Electrically Assisted Global Springback Elimination After Single Point Incremental Forming
Authors: Neveux Trey , Ruszkiewicz Brandt J. , Grimm Tyler , Roth John T. , Ragai Ihab
Published: September 2016

There has been a push in the automotive and aerospace industries towards die-less forming processing that are able to reduce both part cost and part energy. Incremental forming is a die-less forming process that fabricates parts using hemispherical tools following a tool path (similar to that found with conventional milling operations), that slowly deforms the sheet metal into the final desired configuration. Global springback for incremental forming, as defined herein, occurs after the part is unclamped from the retaining fixture. This form of springback is currently a significant impediment to the process since, when the part is released, the residual stresses created during the forming process result in significant part distortion and thereby, undesirable part geometries. To reduce this issue, this paper examines the effect on direct electric current on residual stress and springback elimination when applied post forming, which previous work has shown the potential to reduce this issue. This work is an extension of previous work resented at MSEC 2015. The previous work examined applying electric current to areas of high residual stress through the material’s thickness. This work examines the effect of applying electric current along the length and width of a part (path testing). This work concludes that running multiple paths increases springback reduction and the order in which the path testing is conducted has very little appreciable effect on the springback reduction during path testing.
Dieless Double-Sided Incremental Hole-Flanging With Different Toolpath Strategies
Authors: Zhang Huan , Zhang Zixuan , Ren Huaqing , Moser Newell , Cao Jian
Published: September 2016

Incremental sheet forming is a flexible manufacturing process that does not require dedicated dies nor custom tooling. Hole-flanging via the ISF process is rapid and cost-effective, especially in prototyping and low-volume production. In this study, a double-sided incremental hole-flanging method was considered where the top and bottom tools were used as the forming tool and supporting tool respectively. Utilization of these generic, stylus tools provides enhanced flexibility and replaces the need for specific blank holders. The double-sided incremental hole-flanging method was experimentally studied with various toolpath techniques for the forming and supporting tools. Two toolpath strategies were determined that developed a successful symmetric hole-flange. The measured wall thickness was found to be comparatively uniform along the wall of the flange, while in-plane strains demonstrate excellent material formability. Additionally, the optimum strategy was trialed on a self-designed complex profile with shrink flange and stretch flange occur alternatively in an effort to demonstrate the flexibility and generality of the proposed double-sided incremental hole-flanging method. Possible future work in this area is also discussed.
Effects of Tool Deflection in Accumulated Double-Sided Incremental Forming Regarding Part Geometry
Authors: Ren Huaqing , Moser Newell , Zhang Zixuan , Ehmann Kornel F. , Cao Jian
Published: September 2016

Incremental forming is a flexible dieless forming process. In incremental forming, the metal sheet is clamped around its periphery. One or multiple generic stylus-type tools move along a predefined toolpath, incrementally deforming the sheet metal into a final, freeform shape. Compared with the traditional sheet metal forming process, the incremental forming process is more flexible, energy efficient and cost effective due to lower capital investment related to tooling. However, maintaining tight geometric tolerances in incremental formed parts can be a challenge. Specifically, undesired global bending is usually induced near the region between the tools and fixture resulting in a compromise in geometric accuracy.

To address this issue, Accumulated Double-Sided Incremental Forming (ADSIF) is proposed, which utilizes two tools on both sides of the metal to better achieve localized deformation while simultaneously constraining global bending outside the forming area. Moreover, in ADSIF, the two tools are moving from inward to outward, and thus the tools are always forming virgin material and so as to limit forces on the already-formed part. Thus, ADSIF has a higher potential to achieve the desired geometry. Nevertheless, tool deflection due to machine compliance is still an issue that can have a considerable effect on geometric accuracy.

In this work, the effect of tool deflection related to part geometry is studied for the ADSIF process. The nature of using two tools, rather than one, in ADSIF inherently implies that relative tool position is a critical process parameter. It is the region near these two tools where local squeezing and bending of the sheet occurs, the primary modes of deformation found in ADSIF. The change of relative tool positions (i.e., tool gap and relative position angle) are studied in detail by first developing an analytical model. It is concluded that the tool gap will be enlarged under the influence of tool compliance while the relative position angle is less affected. Additionally, a finite element simulation capable of modeling tool deflection is established. The comparison between the simulation results using rigid tools and deformable ones clearly demonstrated the significant influence of tool compliance on part geometry. Lastly, an axisymmetric part with varying wall angles was formed, and it was confirmed that ADSIF demonstrates improved geometry accuracy compared with conventional Double-Sided Incremental Forming.
A Novel Hybrid Heating Method for Elevated Temperature Mechanical Testing of Miniature Specimens
Authors: Li Lin , Ngaile Gracious , Hassan Tasnim
Published: September 2016

The lack of robust testing systems to generate uniform elevated temperatures on specimens in material tests is hindering the advancement of small specimen testing technology (SSTT). The purpose of this study is to develop a novel hybrid heating method combining coil heating and electric-resistance specimen heating to uniformly heat micro specimens in material tests. In a hybrid heating process, two heating coils are used to heat the local temperatures on the specimen ends, and electric current is conducted through the specimen to generate Joule heat and compensate the heat transfer effects of natural convection and radiation around the specimen center area. In this way, a highly uniform temperature distribution can be generated on the specimen between the heating coils. In this study, Thermal-Electrical and Transient Thermal FEA simulations are applied to analyze the temperature distributions and preheating times on the micro specimens under coil heating, electric-resistance specimen heating, and hybrid heating respectively. According to the simulation results, it can be concluded that hybrid heating method can provide the ability to generate highly uniform elevated temperature conditions on different micro tubular specimens with short preheating times.
A New Approach to Manufacturing Biocomposite Sandwich Structures: Mycelium-Based Cores
Authors: Jiang Lai , Walczyk Daniel , McIntyre Gavin , Bucinell Ronald
Published: September 2016

A new approach to manufacturing biocomposite sandwich structures is introduced. Materials used in the biocomposite are natural textile reinforcement, mycelium-bound agricultural waste as core, and bioresin. This paper focuses on three specific steps of the seven-step manufacturing process: filling pre-stamped textile shells with core mixture; allowing the core material to grow thereby binding reinforcement particles and textile skins into a unitized preform; and oven drying said preform to drive off moisture and inactivate the mycelium. Specific process details highlighted include design and thermoforming of growth trays, tray sterilization, filling trays with mycelium-inoculated substrates filling and allowing growth to occur, and finally conduction and convection drying/inactivation of the grown parts. To study the new material’s stiffness using different materials and under different processing conditions, specimen dimensions were based on ASTM D7250 and C393 standards. All dried samples were tested in flexure by three-point bending method to determine the stiffness and strength of the resin-less preforms and to identify optimal material combinations.
Additive Manufacturing of Magnetic Field-Responsive Smart Polymer Composites
Authors: Pan Yayue , Lu Lu
Published: September 2016

In this paper, an additive manufacturing process, named Magnetic Field-assisted Projection Stereolithography (M-PSL), is presented for applications such as fabricating magnetic field-responsive smart polymer composites. The 3D printed magnetic field-responsive smart polymer composite creates a wide range of motions, opening up possibilities for various new applications, like sensing and actuation in soft robotics, biomedical devices, and autonomous systems. In M-PSL process, a certain amount of nano- or micro-scale ferromagnetic particles is deposited into resin vat with a programmable microdeposition nozzle. Then a magnetic field is applied to direct the magnetic particles to the desired area. After that, digital mask images are used to cure particles in photopolymer with certain patterns. Important issues like magnetic particle movements, curing mechanisms, and manufacturing process planning are discussed. Two test cases, an impeller and a two-wheel roller, have been successfully fabricated for remote control under external magnetic field, showing the capability of printed smart polymer composites on performing desired functions.
Selective Laser Melting of AISI316L: Process Optimization and Mechanical Property Evaluation
Authors: Liverani Erica , Gamberoni Andrea , Balducci Eleonora , Ascari Alessandro , Ceschini Lorella , Fortunato Alessandro
Published: September 2016

The influence of selective laser melting (SLM) process parameters such as laser power, build direction and scan hatch spacing on mechanical properties, microstructures and porosity formation in AISI 316L components is presented. Experimental activities are performed based on a statistical design-of-experiment approach based on a three-factor, two-level experimental plane. Mechanical tests, as well as optical and SEM analyses were carried out to correlate the resulting microstructures and defects to the process parameters. In order to better characterize the process, gas type, gas flux, coater speed and component positioning were also taken into account.
Primitive Study on Model-Based Process Identification by Utilizing Force Estimation Techniques
Authors: Suzuki Norikazu , Ikeda Ryosuke , Shamoto Eiji
Published: September 2016

This study presents a new method to identify parameters representing cutting process and transfer function of flexible mechanical structures mounted on a traveling stage by utilizing only internal information of computerized numerical control (CNC) system. Disturbance force input to CNC is estimated by disturbance observer and cutting force is estimated based on cutting force model. Analyzing influence of the estimated cutting force on the disturbance force, parameters used in the assumed models of cutting process and structural dynamics are identified in quasi-real-time. Least square method (LSM) is utilized for the parameter identification. Face turning experiment using an ultra-precision machine tool was conducted to verify feasibility of the proposed method. Experimental results clarified that the cutting force coefficient and the modal parameters representing the dynamic characteristics of the force transfer function can be identified accurately by the proposed method.
An Environmental and Cost Analysis of Stamping Sheet Metal Parts
Authors: Cooper Daniel R. , Rossie Kathleen E. , Gutowski Timothy G.
Published: September 2016

Little work has been done on quantifying the environmental impacts and costs of sheet metal stamping. In this work we present models that can be used to predict the energy requirements, global warming potential, human health impacts, and costs of making drawn parts using zinc (kirksite) die-sets and hydraulic or mechanical presses. The methodology presented can also be used to produce models of stamping using other die materials, such as iron, for which casting data already exists.

An unprecedented study on the environmental impacts and costs of zinc die-set production was conducted at a leading Michigan die-maker. This analysis was used in conjunction with electrical energy measurements on forming presses to complete cradle-to-gate impact and cost analyses on producing small batch size hood and tailgate parts. These case studies were used to inform a generalized model that allows engineers to predict the impacts and costs of forming based on as little information as the final part material, surface area, thickness and batch size (number of units produced).

The case studies show that press electricity is an insignificant contributor to the overall impacts and costs. The generalized models highlight that while costs for small batch production are dominated by the die-set, the environmental impacts are often dominated by the sheet metal. These findings explain the motivation behind research into die-less forming processes such as incremental sheet forming, and emphasize the need to minimize sheet metal scrap generation in order to reduce environmental impacts.
Simulation of nonlinear propagation of biomedical ultrasound using pzflex and the Khokhlov-Zabolotskaya-Kuznetsov Texas code
Authors: Qiao Shan , Jackson Edward , Coussios Constantin C. , Cleveland Robin O.
Published: September 2016

Nonlinear acoustics plays an important role in both diagnostic and therapeutic applications of biomedical ultrasound and a number of research and commercial software packages are available. In this manuscript, predictions of two solvers available in a commercial software package, pzflex, one using the finite-element-method (FEM) and the other a pseudo-spectral method, spectralflex, are compared with measurements and the Khokhlov-Zabolotskaya-Kuznetsov (KZK) Texas code (a finite-difference time-domain algorithm). The pzflex methods solve the continuity equation, momentum equation and equation of state where they account for nonlinearity to second order whereas the KZK code solves a nonlinear wave equation with a paraxial approximation for diffraction. Measurements of the field from a single element 3.3 MHz focused transducer were compared with the simulations and there was good agreement for the fundamental frequency and the harmonics; however the FEM pzflex solver incurred a high computational cost to achieve equivalent accuracy. In addition, pzflex results exhibited non-physical oscillations in the spatial distribution of harmonics when the amplitudes were relatively low. It was found that spectralflex was able to accurately capture the nonlinear fields at reasonable computational cost. These results emphasize the need to benchmark nonlinear simulations before using codes as predictive tools.
Perceptions of Group-Based Walks and Strategies to Inform the Development of an Intervention in Retirement Villages: Perspectives of Residents and Village Managers
Authors: Thøgersen-Ntoumani Cecilie , Ntoumanis Nikos , Uren Hannah , Stathi Afroditi , Wold Catrina , Hill Keith D.
Published: September 2016

The aim of the current study was to explore perceptions of group-based walking and gather suggestions to inform the development of a group-based walking intervention among older adults in retirement villages. Twenty-four physically inactive residents (16 female, 8 male; age range: 69–88) and four managers from four retirement villages were interviewed. Inductive thematic analysis revealed six broad themes: lack of motivation, values versus constraints, fears and confidence, need for structure, creating a sense of belonging, and the physical environment as a double-edged sword. Proposed intervention strategies included using trained walk leaders, using small groups, planning for flexibility, setting attainable goals, creating a routine, creating opportunities for sharing experiences, and planning a variety of walks. Group-based walking programs may be used to promote physical activity but careful planning of such programs is needed to make them appealing and feasible to a diverse group of residents.
The NF-κB subunit RelB controls p100 processing by competing with the kinases NIK and IKK1 for binding to p100
Authors: Fusco Amanda J. , Mazumder Anup , Wang Vivien Ya-Fan , Tao Zhihua , Ware Carl , Ghosh Gourisankar
Published: September 2016

The NF-κB subunit RelB determines whether inhibitory or transcriptionally active complexes are formed during noncanonical signaling.
Bypassing STAT3-mediated inhibition of the transcriptional regulator ID2 improves the antitumor efficacy of dendritic cells
Authors: Li Haiyan S. , Liu Chengwen , Xiao Yichuan , Chu Fuliang , Liang Xiaoxuan , Peng Weiyi , Hu Jianhua , Neelapu Sattva S. , Sun Shao-Cong , Hwu Patrick , Watowich Stephanie S.
Published: September 2016

Blocking tumor-derived cytokine signaling in dendritic cells enables engineered dendritic cells to function as an antitumor vaccine.
Paper of note in
Science Translational Medicine
Authors: Ferrarelli Leslie K.
Published: September 2016

This week’s article describes how natural killer cells might be harnessed as a new immunotherapy to treat patients with acute myeloid leukemia.
Antimold Prophylaxis May Reduce the Risk of Invasive Fusariosis in Hematologic Patients with Superficial Skin Lesions with Positive Culture for Fusarium
Authors: Varon Andrea G. , Nouér Simone A. , Barreiros Gloria , Trope Beatriz Moritz , Akiti Tiyomi , Nucci Marcio
Published: September 2016

Hematologic patients with superficial skin lesions on admission growing
Fusarium
spp. are at a high risk for developing invasive fusariosis during neutropenia. We evaluated the impact of primary prophylaxis with a mold-active azole in preventing invasive fusariosis in these patients. Between August 2008 and December 2014, patients with acute leukemia or aplastic anemia and recipients of hematopoietic cell transplants were screened on admission with dermatologic and direct exams and fungal cultures of superficial skin lesions. Until November 2009, no interventions were made. Beginning in December 2009, patients with baseline skin lesions and a direct exam and/or culture suggestive of the presence of
Fusarium
spp. received prophylaxis with voriconazole or posaconazole. Skin lesions in the extremities (mostly onychomycosis and interdigital intertrigo) were present on admission in 88 of 239 episodes (36.8%); 44 lesions had hyaline septate hyphae identified by direct exam, and cultures from 11 lesions grew
Fusarium
spp. Antimold prophylaxis was given for 20 episodes (voriconazole for 17 and posaconazole for 3). Invasive fusariosis was diagnosed in 14 episodes (5.8%). Among patients with baseline skin lesions with positive cultures for
Fusarium
spp., 4 of 5 without antimold prophylaxis developed invasive fusariosis versus 0 of 6 with antimold prophylaxis (
P
= 0.01; 95% confidence interval for the difference between proportions, 22% to 96%). Primary antifungal prophylaxis with an antimold azole may prevent the occurrence of invasive fusariosis in high-risk hematologic patients with superficial skin lesions on admission growing
Fusarium
spp.
Esculentin-1a-Derived Peptides Promote Clearance of Pseudomonas aeruginosa Internalized in Bronchial Cells of Cystic Fibrosis Patients and Lung Cell Migration: Biochemical Properties and a Plausible Mode of Action
Authors: Cappiello Floriana , Di Grazia Antonio , Segev-Zarko Li-av , Scali Silvia , Ferrera Loretta , Galietta Luis , Pini Alessandro , Shai Yechiel , Di Y. Peter , Mangoni Maria Luisa
Published: September 2016

Pseudomonas aeruginosa
is the major microorganism colonizing the respiratory epithelium in cystic fibrosis (CF) sufferers. The widespread use of available antibiotics has drastically reduced their efficacy, and antimicrobial peptides (AMPs) are a promising alternative. Among them, the frog skin-derived AMPs, i.e., Esc(1-21) and its diastereomer, Esc(1-21)-1c, have recently shown potent activity against free-living and sessile forms of
P. aeruginosa
. Importantly, this pathogen also escapes antibiotics treatment by invading airway epithelial cells. Here, we demonstrate that both AMPs kill
Pseudomonas
once internalized into bronchial cells which express either the functional or the ΔF508 mutant of the CF transmembrane conductance regulator. A higher efficacy is displayed by Esc(1-21)-1c (90% killing at 15 μM in 1 h). We also show the peptides' ability to stimulate migration of these cells and restore the induction of cell migration that is inhibited by
Pseudomonas
lipopolysaccharide when used at concentrations mimicking lung infection. This property of AMPs was not investigated before. Our findings suggest new therapeutics that not only eliminate bacteria but also can promote reepithelialization of the injured infected tissue. Confocal microscopy indicated that both peptides are intracellularly localized with a different distribution. Biochemical analyses highlighted that Esc(1-21)-1c is significantly more resistant than the all-
l
peptide to bacterial and human elastase, which is abundant in CF lungs. Besides proposing a plausible mechanism underlying the properties of the two AMPs, we discuss the data with regard to differences between them and suggest Esc(1-21)-1c as a candidate for the development of a new multifunctional drug against
Pseudomonas
respiratory infections.
Crystal Structure of the Pseudomonas aeruginosa BEL-1 Extended-Spectrum β-Lactamase and Its Complexes with Moxalactam and Imipenem
Authors: Pozzi Cecilia , De Luca Filomena , Benvenuti Manuela , Poirel Laurent , Nordmann Patrice , Rossolini Gian Maria , Mangani Stefano , Docquier Jean-Denis
Published: September 2016

BEL-1 is an acquired class A extended-spectrum β-lactamase (ESBL) found in
Pseudomonas aeruginosa
clinical isolates from Belgium which is divergent from other ESBLs (maximum identity of 54% with GES-type enzymes). This enzyme is efficiently inhibited by clavulanate, imipenem, and moxalactam. Crystals of BEL-1 were obtained at pH 5.6, and the structure of native BEL-1 was determined from orthorhombic and monoclinic crystal forms at 1.60-Å and 1.48-Å resolution, respectively. By soaking native BEL-1 crystals, complexes with imipenem (monoclinic form, 1.79-Å resolution) and moxalactam (orthorhombic form, 1.85-Å resolution) were also obtained. In the acyl-enzyme complexes, imipenem and moxalactam differ by the position of the α-substituent and of the carbonyl oxygen (in or out of the oxyanion hole). More surprisingly, the Ω-loop, which includes the catalytically relevant residue Glu166, was found in different conformations in the various subunits, resulting in the Glu166 side chain being rotated out of the active site or even in displacement of its Cα atom up to approximately 10 Å. A BEL-1 variant showing the single Leu162Phe substitution (BEL-2) confers a higher level of resistance to CAZ, CTX, and FEP and shows significantly lower

K
m

values than BEL-1, especially with oxyiminocephalosporins. BEL-1 Leu162 is located at the beginning of the Ω-loop and is surrounded by Phe72, Leu139, and Leu148 (contact distances, 3.5 to 3.9 Å). This small hydrophobic cavity could not reasonably accommodate the bulkier Phe162 found in BEL-2 without altering neighboring residues or the Ω-loop itself, thus likely causing an important alteration of the enzyme kinetic properties.
Antibiofilm Activity and Synergistic Inhibition of Staphylococcus aureus Biofilms by Bactericidal Protein P128 in Combination with Antibiotics
Authors: Nair Sandhya , Desai Srividya , Poonacha Nethravathi , Vipra Aradhana , Sharma Umender
Published: September 2016

P128 is an antistaphylococcal protein, comprising a cell wall-degrading enzymatic region and a
Staphylococcus
-specific binding region, which possesses specific and potent bactericidal activity against sensitive and drug-resistant strains of
Staphylococcus aureus
. To explore P128's ability to kill
S. aureus
in a range of environments relevant to clinical infection, we investigated the anti-
S. aureus
activity of P128 alone and in combination with standard-of-care antibiotics on planktonic and biofilm-embedded cells. P128 was found to have potent antibiofilm activity on preformed
S. aureus
biofilms as detected by CFU reduction and a colorimetric minimum biofilm inhibitory concentration (MBIC) assay. Scanning electron microscopic images of biofilms formed on the surfaces of microtiter plates and on catheters showed that P128 at low concentrations could destroy the biofilm structure and lyse the cells. When it was tested in combination with antibiotics which are known to be poor inhibitors of
S. aureus
in biofilms, such as vancomycin, gentamicin, ciprofloxacin, linezolid, and daptomycin, P128 showed highly synergistic antibiofilm activity that resulted in much reduced MBIC values for P128 and the individual antibiotics. The synergistic effect was seen for both sensitive and resistant isolates of
S. aureus
. Additionally, in an
in vitro
mixed-biofilm model mimicking the wound infection environment, P128 was able to prevent biofilm formation by virtue of its anti-
Staphylococcus
activity. The potent
S. aureus
biofilm-inhibiting activity of P128 both alone and in combination with antibiotics is an encouraging sign for the development of P128 for treatment of complicated
S. aureus
infections involving biofilms.