bluuebunny/crossref_metadata_2025 huggingface dataset:
Racialized Representations
Authors: Sarzynski Sarah
Published: September 2018

While race was not used as an organizing tool in the Northeast, it was also not entirely absent. The Ligas drew transnational connections between the Northeast and the US Civil Rights movement and African independence movements, positioning the white ruling majority or European colonists as the enemy of the people. Slavery was a common metaphor used to debate the possibilities of Brazil forming a coalition with the Soviet Union or the United States. The historical legacy of slavery in Northeastern Brazil also factored into debates over competing projects for development in the Northeast. Filmmakers focused on rural afro-descendent populations and stories of quilombos (maroon societies), using realism to portray the Nordestino as African, savage, impoverished and determined to survive. These racialized narratives shaped the cultural and political struggles for change in the Northeast while also redefining what it meant to be Nordestino and a part of the Third World.
Desert Borderland
Authors: Ellis Matthew H.
Published: September 2018

Desert Borderland is an investigation of the historical processes that transformed the local experience of place and political identity in the easternmost reaches of the Sahara Desert over the half century before World War I. Lying at the intersection of social and political history, the book shifts perspectives between an array of state and non-state actors to chart the region’s gradual evolution as a contested borderland between two distinct territorial domains—what would ultimately become the modern nation-states of Egypt and Libya. Desert Borderland challenges powerful nationalist assumptions about Egypt’s historical fixity as a bounded political space—assumptions that have been perpetuated in the standard historiography of modern Egypt, due to its overwhelmingly Cairo-centric nature. The book seeks to subvert this prevailing wisdom of Egypt’s timeless geographical unity by adopting, instead, the view from the margins—taking the reader on a tour of key sites throughout the country’s Libyan borderland, such as the oasis of Siwa, where a range of state- and nation-making projects were unfolding throughout the period in question. It argues that national territoriality was not simply imposed on Egypt’s western (or Ottoman Libya’s eastern) domains by centralizing state powers, but rather emerged through a complex and multilayered process of negotiation with the region’s predominantly bedouin and oasis-dwelling inhabitants, who were animated by their own local conceptions of space, sovereignty, and political belonging.
Legal Exceptionalism in Egypt’s Borderlands
Authors: Ellis Matthew H.
Published: September 2018

This chapter opens with a brief overview of the historical geography of the Egyptian West, highlighting the diversity within the region’s human and physical landscapes. It then moves on to illustrate the uneven political geography of the Egyptian nation-state in the late nineteenth century by highlighting two salient themes: the persistence of legal exceptionalism in the western oases and other desert territories, even after Egypt’s state-wide judicial reforms starting in the 1870s; and the state’s fraught efforts to standardize its policy vis-à-vis Egypt’s bedouin population around the country. Both these themes illustrate the emergence of Egypt’s borderlands as enclaves of exceptionalism within the emergent Egyptian nation-state. Accordingly, the chapter questions prevailing notions of territorial sovereignty in the nineteenth century and argues against normative Euro-centric top-down frameworks for understanding the process of state-building in the period.
The Emergence of Egypt’s Western Border Conflict
Authors: Ellis Matthew H.
Published: September 2018

This chapter documents the emergence of a bona fide “border crisis” in the Eastern Sahara in the decade prior to the Italian occupation of Ottoman Libya. Through a nuanced investigation of a range of primary sources, the chapter illustrates the interactive and multilayered process through which a sharper sense of borderland territorialization—a sense of there being distinctive Libyan and Ottoman territorial spheres—emerged in these pivotal years. Bedouin spatial practices were again central, drawing the Ottoman and Egyptian states deeper into political-diplomatic rivalry, while the Italian state seized upon the instability caused by the bedouin unrest to stake its own territorial claims. In this decade of heated inter-imperial rivalry and contestation, Egyptian sovereign capabilities emerged as ascendant in the region, to the deep chagrin of local Ottoman officials.
Du rejet à la réhabilitation : le sort des restaurations de l’époque allemande en Alsace au XXe siècle
Authors: Lefort Nicolas
Published: September 2018

L’Alsace est une région frontière, ballotée entre l’Allemagne et la France au cours de son histoire. Partie intégrante du Saint-Empire romain germanique, elle est rattachée au royaume de France au XVIIe siècle. Suite à la guerre franco-prussienne de 1870, le traité de Francfort de 1871 annexe l’Alsace et une partie de la Lorraine à l’Empire allemand dans lequel elles forment une Terre d’Empire (Reichsland) avec un statut différent des autres Länder. À la fin de la Première Guerre mondiale, l’Alsace-Lorraine retourne à la France, dont elle fait encore partie aujourd’hui. Cet article porte sur la façon comme cette histoire singulière a favorisé les influences artistiques croisées -aussi bien alleman­des que françaises- dans les monuments historiques d’Alsace; générant pendant le vingtième siècle un impact im­portant sur les choix de restauration des architectes, sur leur réception par les spécialistes de la conservation des deux nationalités et sur leur traitement lorsqu’il a fallu developper des restaurations. L’étude de ce phénomène met en lumière la façon comme les relations franco-allemandes ont généré depuis 1945 un changement progressif de regard sur les travaux de l’époque allemande.
L’exotisme dans les cinémas parisiens entre les deux guerres
Authors: Abadie Shahram
Published: September 2018

Cet article interroge, à travers l’étude du cas parisien, l’idée reçue selon laquelle l’exotisme aurait marqué une phase importante de l’architecture cinématographique pendant l’entre-deux-guerres. Il s’agit de mettre en lumière les raisons d’être et l’ampleur de cette tendance en analysant le parcours des architectes et des commanditaires de cinémas ainsi que leur architecture dans le contexte des échanges internationaux avant de terminer par la réception et le devenir de ces exemples d’exotisme. La méthode consiste à croiser nos recherches doctorales avec des travaux sur l’exotisme et l’orientalisme dans l’art occidental. Cette synthèse a montré que le recours aux motifs exotiques dans les salles parisiennes est relativement précoce, mais ce mode décoratif reste marginal par rapport à la tendance Art déco. Cependant, bien que leurs premiers exploitants aient tous fait faillite, la singularité de ces cinémas a été le principal garant de leur survie et préservation comme patrimoine architectural et cinématographique.
Participación de venteros informales de Medellín: una herramienta de ordenación del espacio público*
Authors: Velásquez Gómez Carolina
Published: September 2018

La ciudad de Medellín es una de las ciudades en Colombia con mayor número de proyectos implementados para la organización de las ventas informales. Sin embargo, es evidente que en el centro de la ciudad aún no se ha logrado un equilibrio espacial entre el vendedor, el peatón y el vehículo. Este artículo tiene como objetivo comprobar la importancia de la participación de los usuarios directos a la hora de formular proyectos urbanos relacionados con ventas callejeras y dar a conocer las percepciones que peatones, vendedores formales y venteros informales tienen sobre el fenómeno y sus implicaciones. La principal herramienta metodológica utilizada fue el diseño participativo: 66 venteros informales regulados ubicados en la calle Pichincha entre Carabobo y Bolívar del centro de Medellín trabajaron de forma colaborativa con la academia para identificar sus principales necesidades, problemas y soluciones.
Formación ciudadana en comportamientos urbanos responsables: Etnografía rápida orientada a la convivencia en el espacio público urbano
Authors: Páramo Pablo , Contreras Díaz Margarita María
Published: September 2018

Se desarrolló un estudio dirigido a analizar el efecto del diseño de un metacontingencia apoyada en una señalización urbana en el seguimiento de reglas que guían la adopción de comportamientos urbanos responsables a lo largo de una avenida de la ciudad de Cúcuta, Colombia. Tras una evaluación de etnografía rápida, que incluyó entrevistas a gestores urbanos y ciudadanos y un experimento de campo, se evaluó el efecto de la metacontingencia sobre comportamientos del individuo en el espacio público. Los resultados confirman que el arreglo entre la interdependencia de los individuos y las consecuencias anunciadas en la señalización produce cambios significativos en la conducta de los ciudadanos que circulan por el espacio público. Se discuten las implicaciones de los hallazgos para el fortalecimiento de la convivencia ciudadana como una práctica cultural.
High-Throughput 3D Printing of Customized Imaging Lenses
Authors: Chen Xiangfan , Liu Wenzhong , Dong Biqin , Ware Henry Oliver T. , Zhang Hao F. , Sun Cheng
Published: September 2018

The emerging 3D printing technology has the potential to transform manufacturing customized optical elements, which currently heavily relies on the time-consuming and costly polishing and grinding processes. However, the inherent speed-accuracy trade-off seriously constraints the practical applications of 3D printing technology in optical realm. In addressing this issue, here, we report a new method featuring a significantly faster fabrication speed, at 24.54 mm3/h, without compromising the fabrication accuracy or surface finish required to 3D-print customized optical components. We demonstrated a high-speed 3D printing process with deep subwavelength (sub-10 nm) surface roughness by employing the projection micro-stereolithography process and the synergistic effects from the grayscale photopolymerization and the meniscus equilibrium post-curing methods. Fabricating a customized aspheric lens with 5 mm in height and 3 mm in diameter could be accomplished in less than four hours. The 3D-printed singlet aspheric lens demonstrated a maximal imaging resolution of 2.19 μm with low field distortion less than 0.13% across a 2-mm field of view. This work demonstrates the potential of 3D printing for rapid manufacturing of optical components.
Toward a New Mathematical Definition of Datums in Standards to Support Advanced Manufacturing
Authors: Shakarji Craig M. , Srinivasan Vijay
Published: September 2018

Recent advances in the digitization of manufacturing have prompted ASME and ISO standards committees to reexamine the definition of datums. Any new definition of datums considered by the standards committees should cover all datum feature types used in design, and support both traditional metrological methods and new digital measurement techniques. This is a challenging task that requires some careful compromise. This paper describes and analyzes various alternatives considered by the standards committees. Among them is a new mathematical definition of datums based on constrained least-squares fitting. It seems to provide the best compromise and has the potential to support advanced manufacturing that is increasingly dependent on digital technologies.
A Flexible Tactile Sensor Based on Porous Graphene Sponge for Tiny Force Measurement
Authors: Zhu Lingfeng , Wang Yancheng , Wu Xin , Mei Deqing
Published: September 2018

Flexible tactile sensors have been utilized for epidermal pressure sensing, motion detecting, and healthcare monitoring in robotic and biomedical applications. This paper develops a novel piezoresistive flexible tactile sensor based on porous graphene sponges. The structural design, working principle, and fabrication method of the tactile sensor are presented. The developed tactile sensor has 3 × 3 sensing units and has a spatial resolution of 3.5 mm. Then, experimental setup and characterization of this tactile sensor are conducted. Results indicated that the developed flexible tactile sensor has good linearity and features two sensitivities of 2.08 V/N and 0.68 V/N. The high sensitivity can be used for tiny force detection. Human body wearing experiments demonstrated that this sensor can be used for distributed force sensing when the hand stretches and clenches. Thus the developed tactile sensor may have great potential in the applications of intelligent robotics and healthcare monitoring.
Contribution of Five-Axis Machine Geometric Errors and Workpiece Setup Errors to On-Machine Laser Scanning Measurement
Authors: Ibaraki Soichi , Goto Shunsuke , Tsuboi Keisuke , Saito Naoto , Kojima Noriaki
Published: September 2018

On-machine scanning measurement of workpiece geometry has a strong advantage in its efficiency, compared to conventional discrete measurement using a touch-trigger probe. When a workpiece is rotated and tilted, position and orientation errors in workpiece setup with respect to the machine’s rotary axes can be a significant contributor to the measurement error. The machine’s geometric errors also influence the measurement error. To establish the traceability of on-machine laser scanning measurement with workpiece rotation, this paper kinematically formulates their contribution to measured profiles. As a practical application example, this paper studies the sensitivity of work-piece setup errors and rotary axis geometric errors on the error in laser scanning measurement of an axis-symmetric part.
Analytical and Numerical Predictions of Machining-Induced Residual Stress in Milling of Inconel 718 Considering Dynamic Recrystallization
Authors: Feng Yixuan , Pan Zhipeng , Lu Xiaohong , Liang Steven Y.
Published: September 2018

A new analytical model is proposed to predict the residual stress in the milling process of Inconel 718 based upon the mechanics analysis of microstructural evolutions. The model proposes to quantify the effects of dynamic recrystallization process on the material flow stress under combined thermal-mechanical loadings in machining. Physics-based mechanistic model is applied to predict the percentage of dynamic recrystallization and the grain size as functions of the milling process parameters and materials constative attributes. The variation of grain size is expected to alter the yield stress, and such dependency relationship is applied to predict the flow stress, which is also dependent on strain, strain rate, and temperature. The time-varying trajectory of residual stress is then predicted at each milling rotation angle through the transformation from milling to equivalent orthogonal cutting, the calculation of stress distribution in loading process, and the stress change during relaxation. The results of analytical model are validated through numerical prediction. The residual stress profile predicted by proposed analytical model matches better with results from numerical model comparing with model without consideration of dynamic recrystallization, especially within subsurface area, with improved accuracy of peak compressive residual stress prediction.
Identifying High-Value CAD Models: An Exploratory Study on Dimensional Variability As Complexity Indicator
Authors: Camba Jorge D. , Contero Manuel , Company Pedro , Pérez-López David , Otey Jeffrey
Published: September 2018

Digital product data quality has proven to be a unifying theme in designing and reusing efficient products, particularly in the context of the Model-Based Enterprise (MBE). More specifically, the quality of the master model (usually a history-based parametric model) is critical, as it determines the quality of all secondary models used in subsequent downstream processes. However, no quantitative metrics exist that can provide a reliable assessment of quality at a high semantic level. In this paper, we introduce dimensional variability as a quality indicator for parametric models that connects the effective variability range of the dimensional constraints in a model to the robustness and flexibility of the parametric geometry, which determines its reusability. As a validation effort, we report the results of a study where a set of parametric models of varying complexity was analyzed, and discuss the significance of the links between the proposed metric and various aspects of the internal graph structure of the CAD model.
Manufacturing of Antibacterial Additives by Nano-Coating Fragmentation
Authors: Bellisario D. , Quadrini F. , Santo L. , Tedde G. M.
Published: September 2018

This study demonstrates the potential of a novel technique called nano-coating fragmentation to produce silver nanocomposites with antibacterial properties. This process starts from the production of an antibacterial additive without the separate production of silver nanoparticles. The additive was produced by depositing a silver nanofilm on polypropylene (PP) pellets by a physical vapor deposition sputtering process. Different set of sputtering parameters were used and different percentage of Ag were deposited on pellets. Afterwards, PP coated pellets were inserted in an injection molding machine to produce, in a single step, the nanocomposite by using shear forces. In facts, nanoparticles originate by the fragmentation of nano-coatings. The homogenously distributed silver particles were observed by microscope onto the nanocomposite surfaces. Thermal and mechanical properties of the nanocomposites were measured as well. The presence of dispersed nanofiller was confirmed by DSC analysis of the molded samples.
Prediction of Temperature Distribution and Residual Stress in SLM Printed Parts
Authors: Park Hong-Seok , Tran Ngoc-Hien , Jonaet Ansari Md
Published: September 2018

Selective laser melting (SLM) is a powder bed based additive manufacturing (AM) process to manufacture metallic parts. SLM is the complex thermal-physical-chemical process of the interaction between a laser source and metallic powders. The SLM printing method has been applied widely for fabricating the metallic parts. However, the high temperature in heating and fast cooling during SLM process result in the large residual stress which affects to the quality of the SLM printed parts such as distortion and cracks. This research proposes to develop a system for predicting the quality of the part from the manufacturing planning to remove the failures before carrying out the real printing process. For developing such system, a model for predicting the temperature distribution should be generated. From this model, an interrelationship between process parameters and temperature distribution should be derived out. Based on that, the deformation can be predicted by calculating residual stress along with the result of temperature distribution.
Developments and Analyses of Alternative Processes for the Manufacturing of Fiber Metal Laminates
Authors: Mennecart Thomas , Werner Henrik , Ben Khalifa Nooman , Weidenmann Kay André
Published: September 2018

Two innovative processes for the in-situ hybridization of fiber metal laminate (FML) components in one process step are presented. In the first process, the wet compression molding is combined with deep drawing. In the second process, deep drawing is combined with resin transfer molding (RTM). One of the benefits of these processes is a better forming behavior of the FML due to the use of a low viscous monomer mixture which polymerizes directly between the metal blanks. A detailed overview on the manufacturing of such components is given. After showing the process feasibilities, the 3-dimensional components are analyzed regarding their geometry and their forming behavior. The results are used to set a process window and to set a recommended guidance for the process. With the help of the in-situ hybridization, 3-dimensional parts could be produced successfully without using pre-consolidated wrought material, so that a high flexibility of the materials’ choice can be obtained.
A Laser Triangulation-Based 3D Measurement System for Inner Surface of Deep Holes
Authors: Ye Zhu , Lianpo Wang , Gu Yonggang , Chao Zhai , Jiang Baoyang , Ni Jun
Published: September 2018

Basing on the laser-triangulation principle, a deep hole inner surface inspection system is developed in this research. Compared with existing inner surface measurement systems, this research takes assembly errors and refraction distortion into consideration and proposes a flexible laser plane calibration technique based on binocular vision that is easy to operate. The measurement system calibrated by proposed method performs well in the field test in which the maximum absolute error of the measured ring gauge diameter is 3μm. Experiment indicates that this system is accurate and suitable for inner surface measurement. Point cloud registration may be applied in the future to extend the system’s applicability.
Real-Time Control of Cyber-Physical Manufacturing Process Under Uncertainty
Authors: Nannapaneni Saideep , Mahadevan Sankaran , Dubey Abhishek
Published: September 2018

Modern manufacturing processes are increasing becoming cyber-physical in nature, where a computational system monitors the system performance, provides real-time process control by analyzing sensor data collected regarding process and product characteristics, in order to increase the quality of the manufactured product. Such real-time process monitoring and control techniques are useful in precision and ultra-precision machining processes. However, the output product quality is affected by several uncertainty sources in various stages of the manufacturing process such as the sensor uncertainty, computational system uncertainty, control input uncertainty, and the variability in the manufacturing process. The computational system may be a single computing node or a distributed computing network; the latter scenario introduces additional uncertainty due to the communication between several computing nodes. Due to the continuous monitoring process, these uncertainty sources aggregate and compound over time, resulting in variations of product quality. Therefore, characterization of the various uncertainty sources and their impact on the product quality are necessary to increase the efficiency and productivity of the overall manufacturing process. To this end, this paper develops a two-level dynamic Bayesian network methodology, where the higher level captures the uncertainty in the sensors, control inputs, and the manufacturing process while the lower level captures the uncertainty in the communication between several computing nodes. In addition, we illustrate the use of a variance-based global sensitivity analysis approach for dimension reduction in a high-dimensional manufacturing process, in order to enable real-time analysis for process control. The proposed methodologies of process control under uncertainty and dimension reduction are illustrated for a cyber-physical turning process.
Understanding Mechanical Integrity of Metal/Ceramic Interfaces Through In-Situ Micro Mechanical Testing and Multiscale Simulations
Authors: Zhang Xiaoman , Mu Yang , Shao Shuai , Wick Collin , Ramachandran Ramu , Meng Wen Jin
Published: September 2018

Mechanical failures of interfacial regions of ceramic-coating/metal-adhesion-layer/substrate systems were measured quantitatively and observed concurrently through instrumented microscale mechanical testing in-situ a scanning electron microscope (SEM). Failure of the interfacial regions of coating/interlayer/substrate systems was observed in micro-pillar specimens in-situ under different loading conditions, including shear, compression, and tension.

Under shear loading, shear failure of the interfacial region was observed to occur in two stages: an initial uniform shear plastic deformation of the entire metal interlayer followed by an unstable shear-off close to the metal/ceramic interface. Additional testing under compression loading conditions suggests that the unstable shear-off is concomitant with the metal/ceramic interface going from being “locked”, with no relative displacement between materials on the two sides of the interface, to being “unlocked”, with significant relative displacements. Failure of the interfacial region was also observed under tensile loading conditions.

Density functional theory (DFT) and molecular dynamics (MD) studies on one particular metal/ceramic interface, namely Ti/TiN, showed that a weak interaction plane exists in the metal layer near the chemical interface in a coherent Ti/TiN structure. Consequently, the free energy and theoretical shear strength of the semi-coherent Ti/TiN interface is found to depend on the physical location of the misfit dislocation network (MDN). The minimum energy and strength of the interface occur when the MDN is near, but not at the chemical interface. The present work gives new insight into the nature of mechanical failure of metal/ceramic interfaces, is relevant to materials-based engineering of metal/ceramic interfaces, and has applications to engineering of ceramic coating/substrate systems.
Redundancy Allocation for Serial-Parallel System Considering Heterogeneity of Components
Authors: Zhu Zhicheng , Xiang Yisha , Coit David
Published: September 2018

The redundancy allocation problem (RAP) for series-parallel system is a system design problem by selecting an appropriate number of components from multiple choices for desired objectives, such as maximizing system reliability, minimizing system cost. RAP has been extensively studied in the last decades. The majority of existing RAP models assume that components for selection are from homogeneous populations. However, due to manufacturing difficulties and variations in raw materials, many manufactured components/parts are heterogeneous, consisting of multiple subpopulations. In this research, we consider a typical RAP with the objective of maximizing the system reliability subject to the constraint of system cost. Components in each choice are assumed to be degradation-based, and each choice consists one normal subpopulation and several abnormal subpopulations. Numerical examples are investigated to illustrate the impact of the component heterogeneity.
In-Situ Image-Based Monitoring and Closed-Loop Control of Aerosol Jet Printing
Authors: Lombardi Jack P. , Salary Roozbeh (Ross) , Weerawarne Darshana L. , Rao Prahalada K. , Poliks Mark D.
Published: September 2018

Aerosol jet printing (AJP) is a complex process for additive electronics that is often unstable. To overcome this instability, real-time observation and control of the printing process using image based monitoring is demonstrated. This monitoring is validated against images taken after the print and shown highly correlated and useful for determination of printed linewidth. These images and the observed linewidth are used as input for closed-loop control of the printing process, with print speed changed in response to changes in observed linewidth. Linear regression is used to relate these quantities and forms the basis of a proportional control. A test using multiple print speeds and the observed linewidths is used to set the control gain. Electrical test structures were printed with controlled and uncontrolled printing, and it was found that the control influenced their linewidth and electrical properties, giving improved uniformity in both size and electrical performance.
Surface Roughness Prediction in Additive Manufacturing Using Machine Learning
Authors: Wu Dazhong , Wei Yupeng , Terpenny Janis
Published: September 2018

To realize high quality, additively manufactured parts, real-time process monitoring and advanced predictive modeling tools are crucial for accelerating quality assurance and quality control in additive manufacturing. While previous research has demonstrated the effectiveness of physics- and model-based diagnosis and prognosis for additive manufacturing, very little research has been reported on real-time monitoring and prediction of surface roughness in fused deposition modeling (FDM). This paper presents a new data-driven approach to surface roughness prediction in FDM. A real-time monitoring system is developed to monitor the health condition of a 3D printer and FDM processes using multiple sensors. A predictive model is built by random forests (RFs). Experimental results have shown that the predictive model is capable of predicting the surface roughness of a printed part with very high accuracy.
High-Fidelity Roll Profile Contact Modeling by Simplified Mixed Finite Element Method
Authors: Zhang Feng , Malik Arif S. , Yu Haoliang
Published: September 2018

Roll diameter surface deviations can generate significant strip flatness defects in the cold rolling of thin gauge metal sheet. The resolution of roll profile deviations can vary between 0.001 and 0.01 mm. In such a high-fidelity contact problem, lack of availability of the measured data, and high computational cost in using the data in simulations, make it very difficult to predict the effects of such deviations. Nonetheless, an understanding of how high-fidelity roll profile deviations can lead to rolled sheet flatness defects is very important since such defects may be unrecoverable. This paper evaluates the ability of a simplified mixed finite element roll-stack model to predict contact behavior effects on the rolled sheet created by high-fidelity roll profile deviations. The simplified finite element method combines 3D Timoshenko beam elements with Winkler elastic foundations. The beam elements are used to capture bending and shear deformation, while the Winkler foundations are tested for their ability to accurately and efficiently capture the high-fidelity flattening-type contact behavior. Results for a simple roll and plate contact case study indicate favorable comparison with the results obtained from a large-scale commercial finite element simulation, and yet the methods requires a small fraction of the associated computing time and memory. The work also offers significant insights into the sheet flatness defects that can arise in cold rolling because of low magnitude but high fidelity roll diameter machining errors.
Stochastic Modeling and Analysis of Spindle Energy Consumption During Hard Milling With a Focus on Tool Wear
Authors: Wang Xingtao , Williams Robert E. , Sealy Michael P. , Rao Prahalada , Guo Yuebin
Published: September 2018

The rapid development of modern science and technology brings with it a high demand for manufacturing quality. The surface integrity of a machined part is a critical factor which needs to be considered in the selection of the appropriate machining processes. By monitoring and predicting tool wear, it is possible to improve sustainability by reducing the scrap rate due to poor surface integrity. In this work, Data Dependent Systems (DDS), a stochastic modeling and analysis technique, was applied to study spindle motor energy consumption during a hard milling operation. The objective was to correlate the spindle power to tool wear conditions using DDS analysis. The spindle power was monitored and the time series trends were decomposed to study the frequency variation with different severities of tool wear conditions and processing parameters. Analysis of Variance (ANOVA) was also used to determine factors significant to the energy consumption by a spindle motor. Experiments indicate that low-level frequency of spindle power is correlated with the amount of tool wear, cutting speed, and feed per tooth. Results suggest that effective tool wear monitoring may be achieved by focusing on low-level frequencies (0.1 rad/sec) highlighted by DDS methodology.
Predictive Modeling of Droplet Velocity and Size in Inkjet-Based Bioprinting
Authors: Wu Dazhong , Xu Changxue , Krishnamoorthy Srikumar
Published: September 2018

Additive manufacturing is driving major innovations in many areas such as biomedical engineering. Recent advances have enabled 3D printing of biocompatible materials and cells into complex 3D functional living tissues and organs using bioink. Inkjet-based bioprinting fabricates the tissue and organ constructs by ejecting droplets onto a substrate. Compared with microextrusion-based and laser-assisted bioprinting, it is very difficult to predict and control the droplet formation process (e.g., droplet velocity and size). To address this issue, this paper presents a new data-driven approach to predict droplet velocity and size in the inkjet-based bioprinting process. An imaging system was used to monitor the droplet formation process. To investigate the effects of excitation voltage, dwell time, and rise time on droplet velocity and droplet size, a full factorial design of experiments was conducted. Two predictive models were developed to predict droplet velocity and droplet size using random forests. The accuracy of the two predictive models was evaluated using the relative error. Experimental results have shown that the predictive models are capable of predicting droplet velocity and size with sufficient accuracy.
Friction Stir Back Extrusion: Tooling and Process Design for AL-1100-O
Authors: Emblom William J. , Babineaux Robin , Nix Charles , Parr Katie , Saltzman Tyler , Olayinka Ayotunde , Wagner Scott W. , Wahab Muhammad A.
Published: September 2018

Friction stir back extrusion has recently been identified as a method for manufacturing stronger, more ductile seamless tubes. The long term goal of the project described here is to miniaturize the process in order to produce highly ductile microscale tubes for biomedical, microscale heat exchanger, and fuel cell manufacturing applications. The process is similar to friction stir welding and processing in that the end of a non-cutting tool rotates against a metal workpiece, heats the workpiece, and creates an ultrafine grain structure. Conventional microtube manufacturing is done by hot direct extrusion using dies with mandrels. After the workpiece passes the mandrels, the tube segments weld together from residual heat. The work described here considers macroscale tooling design prior to down scaling to the multi and microscale. The immediate objective was to develop tooling that can produce 50mm long tubes with 12.5mm outside diameters and 6.35mm inside diameters. Design considerations such as strength, fatigue, buckling, and vibration were considered. This paper documents the development of the tooling design process that was used in order to overcome the various design issues. Tooling failure and analysis is presented as part of the evolution of the tooling design. While majority of the paper discusses the tooling design process, a final design was developed and preliminary results for friction stir back extrusion tests are presented for tubes that are 25 and 50mm long.
A Universal Postprocessor of General Table-Tilting Type of Five-Axis Machine Tools Without Rotational Tool Center Point Function for Actual NC Code Generation
Authors: Fu Guoqiang , Gao Hongli , Gu Tengda
Published: September 2018

The postprocessor is essential for machining with five-axis machine tools. This paper develops one universal postprocessor for table-tilting type of five-axis machine tools without rotational tool center point (RTCP) function. Firstly, positions of two rotary axes and the workpiece in the machine coordinate system (MCS) are introduced into the kinematic chain of the five-axis machine tools. The uniform product of exponential (POE) formula of the tool relative to the workpiece is established to obtain the universal forward kinematics. On this basis, the postprocessor of table-tilting type of five-axis machine tools is developed. The calculation of rotation angles of rotation axes is proposed in details, including the calculation of double solutions, the determination of rotation angles of C-axis and the selection principle of the shortest path of rotation angles. Movements of linear axes are calculated with rotation angles of rotary axes. The generated movements of all axes are actual positions of all axes relative to their zero positions, which can be used for machining directly. The postprocessor does not rely on RTCP function with positions of rotary axes and the workpiece in MCS. Finally, cutting test in VERICUT and real cutting experiments on SmartCNC500_DRTD five-axis machine tool are carried out to verify the effectiveness of the proposed postprocessor.
Effects of Line Energy on Mechanical Properties, Corrosion and Shape Memory Behavior of Laser-Welded NiTinol Joints
Authors: Datta Susmita , Raza Mohammad Shahid , Saha Partha , Pratihar Dilip Kumar
Published: September 2018

In this experimental work, the effects of line energy at constant scan speed on quality of bead-on-plate laser welding of NiTinol sheets were investigated. Variations of bead geometry, changes in microstructure, variation of micro-hardness value along the weld-bead, generation of new phase during welding, changes in tensile strength of the welded samples, corrosion behavior of welded and parent material, and changes in phase transformation temperatures were measured for characterization of welded samples. Laser weld-bead profile was changed from a wine glass without base to glass shape with the increasing line energy. Quality aspects of weld-bead geometry quality aspects showed an increasing trend with line energy. Microstructure was changed during welding due to competitive grain growth. Microhardness values gradually increased from weld centre line to base metal. Tensile strength of the material was reduced after welding due to the formation of brittle intermetallics compounds. A dual failure mode for the welded sample was observed; whereas a single mode of failure was detected for parent material. The corrosion properties of the welded samples were found to be better than that of parent material. Phase transformation temperatures were also found to be reduced after welding.
Knowledge Sharing and Evolution of Industrial Cloud Robotics
Authors: Jin Lixue , Xu Wenjun , Liu Zhihao , Yan Junwei , Zhou Zude , Pham Duc Truong
Published: September 2018

Industrial Cloud Robotics (ICR), with the characteristics of resource sharing, lower cost and convenient access, etc., can realize the knowledge interaction and coordination among cloud Robotics (CR) through the knowledge sharing mechanism. However, the current researches mainly focus on the knowledge sharing of service-oriented robots and the knowledge updating of a single robot. The interaction and collaboration among robots in a cloud environment still have challenges, such as the improper updating of knowledge, the inconvenience of online data processing and the inflexibility of sharing mechanism. In addition, the industrial robot (IR) also lacks a well-developed knowledge management framework in order to facilitate the knowledge evolution of industrial robots. In this paper, a knowledge evolution mechanism of ICR based on the approach of knowledge acquisition - interactive sharing - iterative updating is established, and a novel architecture of ICR knowledge sharing is also developed. Moreover, the semantic knowledge in the robot system can encapsulate knowledge of manufacturing tasks, robot model and scheme decision into the cloud manufacturing process. As new manufacturing tasks arrived, the robot platform downloads task-oriented knowledge models from the cloud service platform, and then selects the optimal service composition and updates the cloud knowledge by simulation iterations. Finally, the feasibility and effectiveness of the proposed architecture and approaches are demonstrated through the case studies.
Automated Surface Inspection Using 3D Point Cloud Data in Manufacturing: A Case Study
Authors: Dastoorian Romina , Elhabashy Ahmad E. , Tian Wenmeng , Wells Lee J. , Camelio Jaime A.
Published: September 2018

With the latest advancements in three-dimensional (3D) measurement technologies, obtaining 3D point cloud data for inspection purposes in manufacturing is becoming more common. While 3D point cloud data allows for better inspection capabilities, their analysis is typically challenging. Especially with unstructured 3D point cloud data, containing coordinates at random locations, the challenges increase with higher levels of noise and larger volumes of data. Hence, the objective of this paper is to extend the previously developed Adaptive Generalized Likelihood Ratio (AGLR) approach to handle unstructured 3D point cloud data used for automated surface defect inspection in manufacturing. More specifically, the AGLR approach was implemented in a practical case study to inspect twenty-seven samples, each with a unique fault. These faults were designed to cover an array of possible faults having three different sizes, three different magnitudes, and located in three different locations. The results show that the AGLR approach can indeed differentiate between non-faulty and a varying range of faulty surfaces while being able to pinpoint the fault location. This work also serves as a validation for the previously developed AGLR approach in a practical scenario.
Experimental and Statistical Study on Magnetic-Field Assisted Finishing of Mold Steel Using Nano-Scale Solid Lubricant and Abrasive Particles
Authors: Lee Pil-Ho , Chung Haseung , McCormick Patrick Steven , Kwon Patrick , Nguyen Hoa , Yang Yuhang , Shao Chenhui
Published: September 2018

Magnetic field-assisted finishing (MAF) is a surface quality enhancing process that utilizes a flexible brush composed of ferrous metal and abrasive particles. This paper experimentally and statistically investigates the characteristics of a MAF process with nano-scale solid lubricant. A new MAF tool was developed by integrating iron and abrasive particles, and nano-scale solid lubricant. In this experiment, the optical microscopic images of the surface are obtained to measure the surface roughness resulting from MAF processes with varying the content of abrasive particles and the presence of nano-scale solid lubricant. Furthermore, spatial statistics techniques are used to quantitatively evaluate the quality of the surface resulting from each combination of MAF parameters. It is demonstrated that the size and type of abrasive particles mainly affect MAF process and the newly developed MAF tool with nano-scale solid lubricant can improve the final surface quality.
Gaussian Process Model for Touch Probing
Authors: Wang Xilu , Qian Xiaoping
Published: September 2018

In this paper, we present an approach to determine probing points for the CMM (coordinate measurement machine) measurement. A surface uncertainty based approach is developed to maximize the amount of information acquired by the touch probing of the surface deviations caused by machining errors. The surface uncertainty is modeled by the Gaussian process model and the probing points are selected to minimize the maximum surface uncertainty (surface variance) conditioned on the touch probings at the selected points. The algorithm has been tested with various numerical examples and has been applied in real machining scenarios. The surface reconstruction error based on the developed algorithm is 50% smaller than uniform sampling. The experiments of on machine probing has validated that the selected points can adequately capture the machining errors.
Effect of Graphene Addition on Crack Propagation Resistance in Glass Fibre Reinforced Polymer Matrix Composite
Authors: Vigneshwaran G. V. , Prabu S. Balasivanandha , Paskaramoorthy R.
Published: September 2018

The effect of graphene nanoplatelets (GNPs) on enhancing the interlaminar fracture toughness of glass fiber/epoxy composites was investigated. The GnPs were physically deposited on the fiber surface by the dip coating technique. The composites were fabricated by hand layup technique followed by the compression molding process. Mode-I fracture test was conducted on the composite specimens. Crack propagation was studied by the digital image correlation (DIC) technique. Mode-I fracture toughness for composites loaded with 0.5 wt.% GnPs showed improvement by an average of 60% when compared to the pristine composites. It is concluded that the addition of GnPs produces a strong fiber/matrix interface bonding which effectively limits the crack propagation.
A Novel Magnetic Source Design for Flexible Fixturing Based on Magnetorheological Fluid
Authors: Wang Yongqing , Luo Qi , Liu Haibo , Liu Kuo , Wu Jiakun
Published: September 2018

Magnetic source configuration plays an important role in flexible fixturing based on magnetorheological fluid (MRF). In this article, a novel magnetic source connected to spindle of machine tool is designed to generate specific magnetic field in machining region. The magnetic field can follow machining trajectory in real time, solidifying magnetorheological fluid under current machining region and constituting a mirror support to axial milling force. The magnetic field makes magnetorheological fluid work in squeeze mode, thus providing a stronger supporting capability under the same magnetic field. The magnetic source has self-cooling function, permitting a very strong coil current throughout the whole machining process. Compared with other magnetic sources used in magnetorheological fixturing, magnetic source researched in this paper is more universal and economical.
In Situ Functional Monitoring of Aerosol Jet-Printed Electronic Devices Using a Combined Sparse Representation-Based Classification (SRC) Approach
Authors: Salary Roozbeh (Ross) , Lombardi Jack P. , Weerawarne Darshana L. , Tootooni M. Samie , Rao Prahalada K. , Poliks Mark D.
Published: September 2018

The goal of this work is in situ monitoring of the functional properties of aerosol jet-printed electronic devices. In pursuit of this goal, the objective is to develop a multiple-input, single-output (MISO) machine learning model to estimate the device functional properties in a near real-time fashion as a function of process parameters as well as 2D/3D features of line morphology. The aim is to use the MISO model for in situ estimation and thus, monitoring of line/device resistance in aerosol jet printing (AJP) process. To realize this objective, silver nanoparticle structures are printed by varying three process parameters: (i) sheath gas flow rate (ShGFR), (ii) exhaust gas flow rate (EGFR), and (iii) print speed (PS). Subsequently, line morphology is captured in situ using a high-resolution charge-coupled device (CCD) camera, mounted coaxial to the nozzle. Besides, utilizing 2D/3D quantifiers (introduced in the authors’ previous publications), the line morphology is further quantified, and the extracted features (e.g., line width, overspray, cross-sectional area, etc.) are fed as inputs to a novel sparse representation-based classification (SRC) model. The four-point probe method is used for measurement of resistance, and definition of a priori classification labels. The outcome of this research paves the way for future control of device functional properties in AJP process.
Friction Stir Lap Welding of Thin AA6061-T6 and AISI304 Sheets at Different Values of Pin Penetrations
Authors: Mahto Raju Prasad , Pal Surjya K.
Published: September 2018

The present paper focuses on the influence of pin penetration on joint strength achieved in friction stir lap welding between AA6061-T6 and AISI304. Penetration of pin into the steel substrate, which is placed below the aluminium, has an influencing role in achieving a good weld. Beyond a certain depth of penetration of pin into the steel, non-uniform thicker intermetallic compound and the weld defects have been found. Defects were found to be located in the stir zone. Thus, an excessive penetrations of the pin into the steel matrix has been produced a detrimental effect to the weld strength. An optimum penetration of pin has been experimentally found out.