bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Variable Phase Volume Fractions on the Effective Thermo-Mechanical Properties of Metal-Ceramic Composites With Graded Microstructures
Authors: Deierling Phillip , Zhupanska Olesya I. , Pasiliao Crystal
Published: March 2016

The present paper is specifically concerned with the evaluation of the effective temperature-dependent elastic, thermal and thermo-elastic material properties of artificially graded Ti-TiB2 microstructures (through thickness only). Effective properties of Ti-TiB2 composite are obtained using micromechanics models and finite element analysis of representative volume elements (RVEs). Two approaches have been adopted and compared to determine the proper RVE. In a fashion similar to previous studies [1], RVEs are generated by considering regions that have a uniform to slow variation in material composition (i.e., constant volume fraction), resulting in statistically homogenous piece-wise RVEs of the graded microstructure neglecting interaction from neighboring cells. In the second approach, continuous RVEs are generated by considering the entire FGM. As pointed out by Anthoine [2], modeling of the complete variation in a microstructure may influence the surrounding layers due to the interactions of varying material composition, particularly when there is a steep variation in material composition along the grading direction. To determine these effects of interlayer interactions, FGM microstructures were generated using three different types of material grading functions, linear, quadratic and square root, providing uniform, gradual and steep variations, respectively. Finite element analysis was performed to determine effective properties of the composite over a wide temperature range.
Osteo-Induction of Human Adipose Derived Stem Cells Cultured on Poly (L-Lactic Acid) Scaffolds Prepared by Thermally Induced Phase Separation Method
Authors: Chinnasami H. , Devireddy R.
Published: March 2016

Bio-degradable Poly (l-lactic acid) (PLLA) scaffolds synthesized using thermally induced phase separation (TIPS) method was used to load cryo-preserved human adipose derived stem cells (hASCs). To make the scaffolds, PLLA-Dioxane solutions were formed by dissolving PLLA in 1,4-Dioxane with three different compositions (wt/vol). These PLLA-Dioxane solutions, frozen in three different cooling rates were lyophilized at 0.037bar and −70°C for 48hrs resulting in porous PLLA scaffolds. Based on the porosity, pore size and compressive strength, a suitable scaffold was chosen to investigate its bio-compatibility and osteo-inductive potential.
Microstructural Analysis of Porcine Skull Bone Subjected to Impact Loading
Authors: Ranslow Allison N. , Kraft Reuben H. , Shannon Ryan , De Tomas-Medina Patricia , Radovitsky Raul , Jean Aurelie , Hautefeuille Martin Pierre , Fagan Brian , Ziegler Kimberly A. , Weerasooriya Tusit , Dileonardi Ann Mae , Gunnarsson Allan , Satapathy Sikhanda
Published: March 2016

Skull fracture can be a complex process involving various types of bone microstructure. Finite element analysis of the microscopic architecture in the bone allows for a controlled evaluation of the stress wave interactions, micro-crack growth, propagation and eventual coalescence of trabecular fracture. In this paper, the microstructure and mechanics of small-volume sections of a 6-month-old Gottingen Minipig skull were analyzed. MicroCT scans were used to generate finite element models. Various computational methods were investigated for modeling the intricacies contained within the porous microstructure of the trabecular bone. Pores were explicitly meshed in one method, whereas in the second, a mesh was created from a microCT image-informed mapping algorithm that mapped the trabecular porosity from an image stack to a solid volume mesh of the model. From here, all models were subject to uniaxial compression simulations. The output of the simulations allowed for a detailed understanding of the failure mechanics of the skull structure and allowed for comparison between the methods. Fracture typically occurs in the weakest areas where the bone is highly porous and forms a fracture surface throughout the material, which causes the bone to collapse upon itself.
Permeability Testing of Ceramic Foam Filters
Authors: Ostergaard Halsey , Dailey Patrick , Alam Mahabub , Parmigiani John
Published: March 2016

The construction and validation of an apparatus for measuring the permeability of ceramic foam filters (CFFs) at varying water flow rates is presented here. Commercially available CFFs are specified by pores per inch, which does not uniquely determine the flow characteristics of CFFs. Permeability, the pressure drop per unit filter thickness as a function of velocity, is desired for modeling and quality control purposes. Permeability is typically described with the Forchheimer equation, which can be broken into linear (Darcy) and quadratic (non-Darcy) components. Linear dependence comes from laminar flow at low flow rates, and is scaled by viscosity, while the square dependence dominates at high flow rates, and is scaled by fluid density.

CFF measurement systems are not commercially available, and while several examples are found in literature, they are expensive and labor intensive to operate, and are usually limited to specific sizes of filter. The methodology, apparatus, and verification work presented here aims to reduce the cost, time, and complexity of measuring the permeability of commercially available CFFs of different sizes and porosities.

Water is used as the working fluid, which is pumped through a CFF held in a modular cartridge. Pressure transducers are mounted close to the filter on either side. For testing different diameters of commercially available CFFs, different inlet and outlet pipe sizes are used to approximately match the diameter of the filter. This approach avoids the need for computational modeling of an effective filter diameter when the pipe and filter diameters do not match. Long, straight rigid pipe runs are used on the inlet to ensure fully developed flow profiles. Flow is measured with a magnetic flow meter. Pressure drop and flow rate are recorded at discrete flow rates after allowing the system to settle to a constant flow rate. A continuously variable methodology was evaluated and rejected. During testing, it was found that the decreased viscosity of water heated by the pump during long testing runs affected the measured permeability. To compensate, water temperature is measured during each run, and the viscosity is calculated for each run. The linear and quadratic permeability coefficients are determined by fitting a quadratic model through pressure drop data as a function of flow rate.

In order to verify the accuracy of the device, a validation disc was created. A 49.6 mm disc of aluminum was drilled with 1,467 evenly spaced holes. An analytical formula from literature was used to calculate the theoretical permeability of the array. The measured permeability was below the calculated value, but surface defects in the disk were shown to have a large impact on measured permeability.
Simulation Platform for Rapid Testing of Methods to Control Exothermic Chemical Reactions
Authors: Choi Siusan , Rege Alok A. , Dennis Brian H.
Published: March 2016

In many applications involving chemical reactions, the efficiency of the process is dependent on the ability to control the temperature of the system. In case of an exothermic chemical reaction, maintaining the desired temperature of the system becomes difficult when the reaction heat is released rapidly once an activation temperature is reached. In this study, a multi-platform coupled simulation using ANSYS-FLUENT and MATLAB/Simulink was established to simulate the chemically reacting flows coupled with different control algorithms. To demonstrate this system, a simple test case was created. A fixed-bed reactor was modelled in ANSYS-FLUENT and was coupled with two different control algorithms including Proportional-Integral-Derivative Control (PID) and Model Predictive Control (MPC) compiled in Simulink. The two software packages exchanged data via a shared file system, thus allowing each package to run on a separate computing platform. This multi-platform coupled simulation framework enabled this study to investigate the ability of different control techniques to maintain the temperature of the system as a function of reaction rate. The results verify the feasibility of using such platform to test different control algorithms for a temperature control problem.
Experimental and Computational Fluid Dynamic Analysis of Melt Flow Behavior in Fused Deposition Modelling of Poly(lactic) Acid
Authors: Stewart Samuel R. , Wentz John E. , Allison Joseph T.
Published: March 2016

Fused deposition modelling (FDM) creates three-dimensional parts by feeding a rigid thermoplastic filament through a heated barrel to achieve a semi-fluid state and then extruding it layer-by-layer to create a part geometry. The melt flow behavior within FDM must be analyzed in order to correctly understand the temperature gradients within the system to promote part quality, process control, and efficiency. The presented research consists of analyzing the melt flow behavior of polymer poly(lactic) acid (PLA) within FDM. This includes an experimental analysis of the power output of the resistive heat source, a theoretical analysis of external coefficients of heat-transfer, and an experimental validation of liquefier temperatures. A three-dimensional fluid-flow model is created using the accurate geometry of the extruder assembly, calculated conditions from initial experimental results, and referenced material properties. Results of this research include a significant temperature difference between the areas of the liquefier assembly close in proximity to the power source to those further away such as the inlet and outlet, suggesting that external heat transfer mechanisms play a significant role in liquefier dynamics, contrary to the more common assumption of constant wall temperature or constant heat flux used in modeling. The research presented provides new information regarding the melt flow of PLA, a method of modeling external heat transfer, and a way of understanding power consumption that can lead to liquefier design improvements. The process itself will also aid in identifying modeling considerations for further investigations of melt flow involving various extruder designs and material options. Specifically, the use of this type of comprehensive model is of interest to the additive manufacturing community with respect to thermally sensitive component specification and heating and cooling needs within process based on changing system parameters such as extrusion temperature and mass flow rates (i.e. material feed rate and/or change in extrusion diameter).
Optimizing the Curriculum in Thermodynamics and Heat Transfer With Better Labs, In-Class Demonstrations and Interesting Realistic Problems to Enhance Learning
Authors: Larsen K. , Hossain A. , Weiser M.
Published: March 2016

The primary objective of a thermodynamic/heat transfer course is to provide the fundamental knowledge necessary to understand the behavior of thermal systems. A thermodynamic/heat transfer course provides a detailed calculus-based analysis of energy, entropy, exergy, conduction, convection, and radiation using these concepts to calculate the behavior and efficiencies of different processes and cycles. Proper conceptual and theoretical understanding of thermodynamics/heat transfer is very important to solve real life problems. In order to understand and properly use the concepts, it is necessary that there be effective labs and in-class demonstrations, as well as realistic problems to serve this purpose. Most thermodynamic/heat transfer courses have some labs and some courses use in-class demonstrations that attempt to apply what is being learned in the class room. How effective these labs and demonstrations are in helping the students understanding of the thermodynamic/heat transfer principles is questionable. To facilitate theoretical learning, instructors need to also solve a variety of interesting problems in thermodynamics/heat transfer, besides solving the conventional problems from the text book. Solving these realistic problems helps students to also enhance their conceptual understanding, and, motivate students to continue their learning. This paper describes an example of an interesting heat transfer problem that compares an analytical solution with that of an FEA solution to help engage the students in learning how to apply both approaches to a realistic problem. Furthermore, this paper discusses a series of labs that are currently used at Eastern Washington University (EWU) to help students apply what they are learning in a thermodynamic/heat transfer course. The labs at EWU are compared to a survey conducted at 25 universities to find other possible labs and in-class demonstrations. From this study, the best labs and in-class demonstrations will be discussed, explored, and implementation recommendations will be given.
VHC Performance Evaluation at Connstant Flow: 30 L/Min
Authors: Oliveira Ricardo F. , Cabral Marques Helena Maria , Machado Ana V. , Teixeira José Carlos , Teixeira Senhorinha F.
Published: March 2016

Asthma treatment provided by a pressurized Metered Dose Inhaler (MDI) coupled to a Valved Holding Chamber (VHC), in cases of children younger than 5 years old, is a standard well-stablished in the medical community. The lack of experimental studies for comparison of several commercial VHC alternatives is the main goal of this study. The VHC device needs to be evaluated in terms of Fine Particle Mass (FPM) emitted and Performance. Such assessment was made based on a cascade impaction methodology (i.e. Multi-Stage Liquid Impinger - MSLI) at 30 ± 5 L/min. This impactor apparatus is composed by five stage of impaction, where the spray particle size distribution is collected by ranges of aerodynamic diameter, from coarse to fine particles. This evaluation was executed for 8 VHC devices: Aerochamber Plus®, A2A Spacer®, Compact Space Chamber Plus®, Space Chamber Plus®, Nebuchamber®, Vortex®, OptiChamber Diamond® and Volumatic®. The Ventolin® (salbutamol sulphate 100 μg/dose) was the chosen MDI device, due to its widely prescription and acceptance. Drug mass per stage was quantified by UV-Vis Spectrometry, through washing solutions of NaOH 0.01M.

Results show clear distinction between the use of MDI alone or coupled with any VHC. Its Emitted Dose (ED) is higher when coupled to a VHC, although the FPM emitted is not different. In other hand the use of VHC provides a reduction from 82.7% to 95.3% of the Throat deposition in comparison to MDI alone.

Results point the Aerochamber, Volumatic and Nebuchamber as the highest FPM emitters (27.5 ± 2.4 μg, 27.3 ± 2.7 μg, 26.5 ± 1.8 μg) and with high performance indexes (5.3 ± 0.1, 6.6 ± 1.3, 5.0 ± 0.4).

A complete device characteristics analysis is provided, showing that Throat deposition is highly related to the valve design. The Leaflet design (≈5.0 μg) has lower throat deposition than Duck type (≈9.5 μg).

A Handling and Attractiveness index is calculated and plotted against the Performance index divided by the device cost. This analysis shows that Volumatic is the best investment (1.73 ± 0.34 £−1) for home / hospital use (2.0 g−1·m−3), while the Aerochamber shows the best portability (53.2 g−1·m−3) and a reasonable investment (1.10 ± 0.02 £−1).
Thermal Simulations for Cooling Rate Mapping in Electron Beam Additive Manufacturing
Authors: Cheng Bo , Chou Y. Kevin
Published: March 2016

The powder-bed electron beam additive manufacturing (EBAM) process is a relatively new AM technology that utilizes a high-energy heat source to fabricate metallic parts in a layer by layer fashion by melting metal powder in selected regions. EBAM can be able to produce full density part and complicated components such as near-net-shape parts for medical implants and internal channels. However, the large variation in mechanical properties of AM build parts is an important issue that impedes the mass production ability of AM technology. It is known that the cooling rate in the melt pool directly related to the build part microstructure, which greatly influences the mechanical properties such as strength and hardness. And the cooling rate is correlated to the basic heat transport process physics in EBAM, which includes a moving heat source and rapid self-cooling process. Therefore, a better understanding of the thermal process of the EBAM process is necessary. In this study, a 3D thermal model, using a finite element method (FEM), was utilized for EBAM heat transport process simulations. The process temperature prediction offers information of the cooling rate during the heating-cooling cycle. The thermal model is applied to evaluate, for the case of Ti-6Al-4V in EBAM, the process parameter effects, such as the beam speed and power, on the temperature profile along the melt scan and the corresponding cooling rate characteristics. The relationship between cooling rates and process parameters is systematically investigated, through multiple simulations, by incorporating different combinations of process parameters into the thermal model. The beam scanning speed vs. beam power curves of constant cooling rates can be obtained from 3D surface plots (cooling rate vs. different process parameters), which may facilitate the process parameters selections and achieve consistent build part quality through controlling the cooling rate.
Damage Simulation of Stitched CFRP Laminates Under High-Velocity Projectile Impact
Authors: Yoshimura Akinori , Mikami Yasuhito , Nakayama Masahiro , Ogasawara Toshio , Watanabe Naoyuki
Published: March 2016

In this study, numerical analytical model which simulates the damage behavior of the through-the-thickness stitched CFRP laminates under high velocity impact (HVI) is developed. The simulation results are compared with experimental results for validation of the developed model. Through-the-thickness stitched CFRP laminates have good mechanical properties such as higher delamination toughness and better impact resistance than that of conventional laminates. In this study, rigid body impact tests were conducted for the stitched CFRP laminates. Test results revealed that through-the-thickness stitching effectively suppressed the propagation of the delamination, and it increased the performance against the perforation. Among them, moderate stitched CFRP had the highest performance. In order to analyze the HVI damage behavior of the stitched CFRP laminate, special finite element model was developed. In the model, the in-plane tensile and compressive fiber damages were considered by using stress criterion. Transverse cracks were modeled by continuum damage mechanics (CDM). Delamination was modeled by cohesive zone model (CZM). The effect of the stitch threads were introduced by multiscale approach. Out-of-plane tensile tests were performed for small specimens those include single stitching. Small finite element model which contains a non-linear spring element was prepared, and the load-displacement relationship of the non-linear spring was decided so that the result of the model agreed with the tests. Then, the spring elements were introduced to the HVI simulation model. The simulation results revealed that stitching bridges the delamination and delamination area was reduced. On the other hand, the simulation results revealed that delamination reduces the tensile stress in the bottom surface of the laminate. Because delamination easily propagate in the moderate stitched laminates, the performance against the perforation of the moderate stitched laminates is the highest among the stitched laminates.
Design and Testing of a Crashworthy Landing Gear
Authors: Kim Tae-Uk , Shin JeongWoo , Lee Sang Wook
Published: March 2016

The development of a crashworthy landing gear is presented based on the civil regulations and the military specifications. For this, two representative crashworthy requirements are applied to helicopter landing gear design; the nose gear is designed to collapse in a controlled manner so that it does not penetrate the cabin and cause secondary hazards, and the main gear has to absorb energy as much as possible in crash case to decelerate the aircraft. To satisfy the requirements, the collapse mechanism triggered by shear-pin failure and the shock absorber using blow-off valve are implemented in the nose and main gear, respectively. The crash performance of landing gear is demonstrated by drop tests. In the tests, performance data such as ground reaction loads and shock absorber stroke are measured and crash behaviors are recorded by high-speed camera. The test data shows a good agreement with the prediction by simulation model, which proves the validity of the design and analysis.
Experimental Study of Mechanical Properties of Additively Manufactured ABS Plastic as a Function of Layer Parameters
Authors: Letcher Todd , Rankouhi Behzad , Javadpour Sina
Published: March 2016

In this study, a preliminary effort was undertaken to represent the mechanical properties of a 3D printed specimen as a function of layer number, thickness and raster orientation by investigating the correlation between the mechanical properties of parts manufactured out of ABS using Fused Filament Fabrication (FFF) with a commercially available 3D printer, Makerbot Replicator 2x, and the printing parameters, such as layer thickness and raster orientation, were considered. Specimen were printed at raster orientation angles of 0°, 45° and 90°. Layer thickness of 0.2 mm was chosen to print specimens from a single layer to 35 layers. Samples were tested using an MTS Universal Testing Machine with extensometer to determine mechanical strength characteristics such as modulus of elasticity, ultimate tensile strength, maximum force and maximum elongation as the number of layers increased. Results showed that 0° raster orientation yields the highest mechanical properties compared to 45° and 90° at each individual layer. A linear relationship was found between the number of layers and the maximum force for all three orientations, in other words, maximum force required to break specimens linearly increased as the number of layers increased. The results also found the elastic modulus and maximum stress to increase as the number of layers increased up to almost 12 layers. For samples with more than 12 layers, the elastic modulus and maximum stress still increased, but at a much slower rate. These results can help software developers, mechanical designers and engineers reduce manufacturing time, material usage and cost by eliminating unnecessary layers that do not increase the ultimate stress of the material by improving material properties due to the addition of layers.
Performance-Index Functions in Networked Control Systems With Disturbance and Noise
Authors: Kim Kuktae , Kim Won-jong
Published: March 2016

This paper presents performance-index functions (PIFs) in networked control systems (NCSs) with disturbance and noise using nonlinear approximations. Based on experimental data, exponential and polynomial approximations are formulated to describe the system performance versus frequency and disturbance. Approximation methods can be used to estimate the amount of disturbance at a given frequency. Once the frequency and the magnitude of disturbance are determined, the optimal sampling frequency can be calculated from PIFs. The exponential and polynomial approximation techniques can be used for an NCS to run within an allowable performance level using PIFs with minimizing the system bandwidth utilization (BU). In this paper, a DC motor speed control system through network is used as an example. From experimental data, the coefficients for exponential and polynomial approximation equations are calculated using a trust-region algorithm and a linear least squares algorithm, respectively. Although the exponential method traces the experimental data better than the polynomial one, it will also take up more resources in real time and may degrade the NCS performance if its calculation time takes more than the allowable time for a given sampling period. Thus a balance between cost and performance should be maintained.
Humidity and Temperature Control Applied to a Controlled Environment Chamber
Authors: Cardona Gil Jorge A. , Pazos Urrea Juan P. , Osorio Marisol , Hincapié Carlos A.
Published: March 2016

The temperature, the relative humidity (RH) and the light are variables that influence and affect considerably the development of plants and mites. The study of the different stimulus’s effect on plants and animals is possible under controlled conditions when the variables of interest are regulated. With this project we aim to obtain a suitable temperature and RH controller, property of the Grupo de Investigaciones Agroindustriales (GRAIN). Formerly, the chamber belonged to this research group and it was used as meat ripening facility, but it was necessary to ensure the proper environment for plants and mites for further research. In order to fulfill this new objective, a better control must be designed. As a final product we obtained a graphic interface in both the PLC (Programmable Logic Controller) and the computer. In this way, the user can set certain conditions of temperature and RH inside the chamber, with and without the requirement of a computer to accomplish the control of these variables.
Simulation of Electric Propulsion Drive With Surface Piercing Propeller for Planing-Hull Watercraft
Authors: Xiros Nikolaos I.
Published: March 2016

A simulation model for planing-hull watercraft propulsion consisting of a 3ph induction motor as prime mover, direct shaft drive, surface piercing propeller as thruster and speed controller was developed, tested, and operated demonstrating the ability to analyze the entire system numerically. The modularity of the model allows for the user to easily substitute different or more advanced modules, or add additional ones to obtain greater level of detail or simulate more complex interactions. Trends indicate an interest in all electric ship design as well as the use of surface piercing propellers for small craft. All-electric drive plants offer distinct advantages due to their flexibility in arrangements, ability to eliminate reduction gears in many cases, and wide range of available sizes. Of particular interest is the ability to apply electric drive to small craft with planing-hull, which achieve significantly higher velocities and where arrangements and maneuverability are of high concern. The accurate control of speed combined with the ability to output fairly constant torque across a wide range of speeds allows application of non-conventional thrusters such as surface piercing propellers to small craft. Due to the availability of towing tank data from a surface piercing propeller, a methodology to translate measured performance data for non-conventional thrusters as a computer simulation block needed to be developed. The derived modeling block of the surface piercing propeller, which took the form of a neural net, was integrated with an AC induction motor prime mover module, detailed dynamic propulsion shaft module and Proportional-Integral (PI) control module. The modules were finally augmented with a block implementing Savitsky’s method for planing-hull modeling. Simulations were conducted using full-scale real-world conditions for a hull Bayliner 170 Bowrider boat the hull of which can be adjusted to accommodate for a 50HP electric motor and a surface-piercing propeller. The runs conducted demonstrated the model functionality and level of detail.
Development of a Smart Pipe Inspection Gauge for Detection of Pipeline Defects
Authors: Olugboji Oluwafemi Ayodeji , Sadiq Adinoyi Abdulmajeed , Olorunsaiye Oluwafemi , Peters David Omeiza , Ajayi Babatunde Ayobami
Published: March 2016

Pipeline defects and oil leakages pose an enormous challenge especially in the oil and gas industries, hence, the need for an effective and economical pipeline inspection system. This work focused on the development of a cost effective In-Line-Inspection tool called a smart pipe inspection gauge (PIG). A Test bed was designed and developed to simulate the impulses experienced by the PIG as it moved along the pipeline. The electronics and sensors embedded in the smart PIG were designed to detect vibrations as it moved along the pipe wall and allowed for the wireless transmission of data collected by the PIG system. The results obtained from the laboratory tests revealed dramatic changes in the vibrational intensity experienced by the smart PIG at various intervals. This validates the use of off-the-shelf sensing equipment with a low cost assembly to detect defects in pipelines.
Design of Low Profile Actuators for Medical Exoskeletons
Authors: Jeong Yoon Jung , Kazerooni Homayoon
Published: March 2016

Lower extremity exoskeletons augment ability of walking, sitting and standing upright with a pair of robotic legs that ambulates the user with mobility disorder. As a mobility aid, being lightweight and compact can highly increase usability by allowing users to navigate through narrow passages. This paper summarizes the design of low profile actuators designed for minimally actuated exoskeleton, a lightweight and low profile powered medical exoskeleton developed in Robotics and Human Engineering Laboratory at UC Berkeley. An analytical method for designing low profile BLDC actuation units, critical hardware design aspects, and initial performance measurements are discussed. A set of pancake DC actuation units was designed, manufactured, assembled, and integrated into a lower limb medical exoskeleton. This exoskeleton was tested by a male 28-year-old paraplegic test pilot with injury level of T12.
Isolation of Circulating Tumor Cells Using Stiffness-Based Filtration Platform
Authors: Celik Emrah , Rongione Nicolas , Bahamonde Amelia , Ao Zheng , Datar Ram
Published: March 2016

Analysis of isolated cancer cells in circulation is proven to help determine the success of the cancer treatment and understand the genetic signature of cancer disease. Scarcity of these cells in blood circulation (1–10 CTC in 1ml blood) however, makes the isolation process extremely challenging. Ever improving CTC isolation methods fall into two main categories: 1.Immunomagnetic separation based on antibody binding to tumor specific biomarkers expressed on the cell 2. Physical separation based on the size of the CTCs. Efficiency in cell isolation is still low in these techniques due to the variation in expression level of tumor specific antigens and tumor cell size. Therefore, tumor cell isolation strategies using new CTC biomarkers must be explored.

In this study, we investigated the feasibility of using mechanical stiffness difference in order to detect and isolate the circulating tumor cells from the blood cells. AFM nanindentation experiments revealed that cancer cells are significantly softer than the surrounding white blood cells and therefore, stiffness can be used as a biomarker for CTC isolation. In addition, finite element analysis simulations have shown that CTC isolation can be performed at high efficiency using stiffness-based isolation. Therefore, stiffness based isolation has a potential to achieve fast, label-free isolation of CTCs at high efficiency for clinical applications.
Built-Up-Edge Formation in Micromilling
Authors: Kovvuri V. , Wang Z. , Araujo A. , da Silva M. B. , Bukkapatnam S. , Hung W. N. P.
Published: March 2016

This paper presents experimental study on conditions for built-up-edge (BUE) formation and its effects in micromilling. Surface finish and BUE area density on a micromilled surface are used to quantify the presence of BUE. A model for surface finish is derived based on the topography of milled surface and tool geometry. Assuming no BUE formation, this empirical model shows the dependence of surface finish on chip load, tool concavity angle, and includes the effect of cutting parameters and milling modes (up-milling or down-milling). Micromilling tools of 100–400 μm diameters are used for milling stainless steel at 10–60 m/min cutting speed, 0.05–1 μm/flute chip load, in minimum quality lubrication condition (MQL). A BUE, embedded onto either a milled surface or tool cutting edge or chip, is identified by scanning electron microscopy and energy dispersive spectroscopy techniques; the severity of BUE formation is quantified as area density when observing a machined surface at high magnification with optical microscopy or interferometry.

Condition for BUE formation is presented by mapping the surface finish and BUE area density against cutting speed and chip load. A microtool would fracture catastrophically at high cutting speeds and/or high chip loads due to excessive dynamic stresses on a microtool; such tool would also fail at the other extreme when low cutting speeds and chip loads promote formation and detachment of BUE on the tool surface, therefore, chipping the fragile microcutting edges of a microtool. There is an optimal zone for effective micromilling without tool failure and BUEs. The measured surface finish approaches the theoretical value when BUE is absent, i.e. micromilling in minimum quantity lubrication at cutting speed between 40–60 m/min and chip load higher than 0.15μm/tooth. The BUE area density for up-milling is lower than that for down-milling at low cutting speed; such difference gradually diminishes when selecting milling parameters in the optimal zone where BUE is practically absent.
Experimental Study of the Maximum Resolution and Packing Density Achievable in Sintered and Non-Sintered Binder-Jet 3D Printed Steel Microchannels
Authors: Elliott Amelia M. , Momen Ayyoub Mehdizadeh , Benedict Michael , Kiggans James
Published: March 2016

Developing high-resolution 3D printed metallic microchannels is a challenge especially when there is an essential need for high packing density of the primary metal. While high packing density could be achieved by heating the structure to the sintering temperature, some heat sensitive applications require other strategies to improve the packing density of primary metal. In this study the goal is to develop microchannels with high green (bound) or pack densities on the scale of 100–300 microns which have a robust mechanical structure. Binder-jet 3D printing is an additive manufacturing process in which droplets of binder are deposited via inkjet into a bed of powder. By repeatedly spreading thin layers of powder and depositing binder into the appropriate 2D profiles, complex 3D objects can be created one layer at time. Microchannels with features on the order of 500 microns were fabricated via binder jetting of steel powder and then sintered and/or infiltrated with a secondary material. The droplet volume of the inkjet-deposited binder was varied along with the print orientation. The resolution of the process, the subsequent features sizes of the microchannels, and the overall microchannel quality were studied as a function of droplet volume, orientation, and infiltration level.
Realization of Surface Morphology and Process Parameter Optimization in MicroEDM Hole Drilling of Maraging Steel 300 Alloy
Authors: Yeole Shivraj , Nunna Nagabhushana Ramesh , Banoth Balu Naik , Alluru Ramya
Published: March 2016

The Micro-Electrical Discharge Machining, popularly known as micro-EDM, is a nonconventional machining process mainly used for producing micro features like micro holes, micro gears, micro moulds etc. that are difficult to be obtained by conventional process. It can machine different types of conductive materials especially the ones which are difficult to cut and machine. Microholes have been drilled using micro-EDM process on various alloys like Ti-6Al-4V, Inconel 718 etc. using electrodes like Copper, Tungsten etc. The parts produced by micro-EDM are widely used in micro-electro-mechanical systems (MEMS), biomedical applications, automotive industry, and defence industry. Selection and use of correct process parameters is of paramount importance for achieving superior surface quality and higher machining rates while performing micro drilling. However, this process has been characterized by low tool wear rate, low machining rate and longer machining time as compared to other non-conventional processes. This paper aims at studying the influence of various process parameters while drilling micro holes on Maraging Steel 300 alloy using a brass electrode. Maraging Steel 300 alloy is widely used in aerospace, tooling and machinery applications. Brass was selected as the electrode material so as to know its influence in the microdrilling process as it is known for achieving high material removal rate along with high wear ratio. Machining parameters considered in this work were pulse on time, pulse off time, tool diameter and current. A total of 27 micro holes of 300 μm, 400 μm and 500 μm were drilled on Maraging Steel 300 alloy as per the orthogonal array design based Taguchi methodology. Experiments were carried out on Toolcraft V04056 micro-EDM machine. Dielectric used was distilled water. The output responses observed were material removal rate, tool wear rate and overcut. Analysis was carried out using signal to noise ratio analysis. Material removal rate, tool wear rate and overcut were found to be influenced mainly by pulse on time and current. In order to know and better understand the surface morphology of the micro-holes, SEM micro-graphs were obtained. Presence of spatters and re-deposited eroded material were observed in few of the drilled micro holes. The results were verified by performing confirmation experiment at the obtained optimum combination. The confirmation results were in close proximity to the predicted results.
A New Strategy of Cavity Cutting Trajectory Generation in High Speed Machining
Authors: Yin Yue , Guo LianShui , Han Ning , Zheng Ji , Zhang Pengpeng
Published: March 2016

High speed machining is widely used in manufacturing. For its high cutting speed, high feeding rate, and high machining accuracy, its requirements for cutting trajectory in high speed machining are so strict that only continuous and smooth trajectories with even cutting loads can lead to high machining efficiency and accuracy. The traditional row or ring machining trajectory fails to meet these requirements. In order to acquire the continuous and smooth machining trajectories, and to avoid load mutation in the machining process, some researchers developed a curvilinear cutting trajectory generating method based on partial differential equation. This trajectory, however, is still made up from free form curve segment, and unable to completely eliminate the effects on smoothness by line segment interpolation, which has a very adverse effect on the efficiency, tool life and machining accuracy.

A new strategy to generate a continuous and smooth cavity cutting trajectories in high speed machining is introduced in this article. The new trajectory determines the necessity-nodes from outside (the boundary) to inside in the way of spiral cutting. It starts from the cavity center with spiral expanding, and each cutting loop adopts end connection between straight line and the tangent arc, meeting continuous first-order constraint satisfaction. The smooth trajectory reduces the amplitude and directing mutation of cutting force, thus effectively avoids the impact on the machining efficiency and machining accuracy by speeding down in the corner. The strategy also, by controlling the row space, ensures that there is no cutting residual.

A cavity machining programming system based on this strategy is developed on Siemens UG-CAM module. The manufacturing of triangle cavities is studied as a case. It turns out that the new trajectory improves efficiency by 26.23% compared with the traditional one. It ensures a stable operation of the cutting tool in machining, therefore effectively extends the tool life. The main advantages are that the new strategy adopts the geometrical drawing strategy and the trajectories are all made up from the straight lines and the tangent arcs. The trajectory can greatly reduce NC code. It thoroughly removes the effort to mind the smooth, continuity and even cutting load of the tool-path.
Tacit Knowledge Reuse in a Next Generation Sustainable Manufacturing Process
Authors: Guerra-Zubiaga David A. , Heiling Drew , Onadipe Olusola , Katuwal Rojan-Kumar , Dhital Prabin , Mamun Abdullah A.
Published: March 2016

Tacit knowledge is a very important intangible asset at manufacturing enterprises and Next Generation Manufacturing Systems (NGMS) is a relevant concept to understand manufacturing paradigms. Some Manufacturing paradigms are Factory of the future (FoF) in a Sustainable Manufacturing environment. There is a need not only to create approaches to understands the NGMS addressing the FoF to support Sustainable Manufacture, but also to capture the key manufacturing tacit knowledge through this process. This paper presents a novel idea about tacit knowledge modeling and reuse in a sustainable manufacturing application.
Pilot-scale electron cyclotron resonance-metal organic chemical vapor deposition system for the preparation of large-area fluorine-doped SnO2 thin films
Authors: Jeon Bup Ju , Hudaya Chairul , Lee Joong Kee
Published: March 2016

The authors report the surface morphology, optical, electrical, thermal and humidity impacts, and electromagnetic interference properties of fluorine-doped tin oxide (SnO2:F or “FTO”) thin films on a flexible polyethylene terephthalate (PET) substrate fabricated by a pilot-scale electron cyclotron resonance–metal organic chemical vapor deposition (PS ECR-MOCVD). The characteristics of large area FTO thin films were compared with a commercially available transparent conductive electrode made of tin-doped indium oxide (ITO), prepared with an identical film and PET thickness of 125 nm and 188 μm, respectively. The results revealed that the as-prepared FTO thin films exhibited comparable performances with the incumbent ITO films, including a high optical transmittance of 97% (substrate-subtracted), low electrical resistivity of about 5 × 10−3 Ω cm, improved electrical and optical performances due to the external thermal and humidity impact, and an excellent shielding effectiveness of electromagnetic interference of nearly 2.3 dB. These excellent performances of the FTO thin films were strongly attributed to the design of the PS ECR-MOCVD, which enabled a uniform plasma environment resulting from a proper mixture of electromagnetic profiles and microwave power.
Amputee Locomotion: Ground Reaction Forces During Submaximal Running With Running-Specific Prostheses
Authors: Baum Brian S. , Hobara Hiroaki , Kim Yoon Hyuk , Shim Jae Kun
Published: March 2016

Individuals with lower extremity amputation must adapt the mechanical interactions between the feet and ground to account for musculoskeletal function loss. However, it is currently unknown how individuals with amputation modulate three-dimensional ground reaction forces (GRFs) when running. This study aimed to understand how running with running-specific prostheses influences three-dimensional support forces from the ground. Eight individuals with unilateral transtibial amputations and 8 control subjects ran overground at 2.5, 3.0, and 3.5 m/s. Ten force plates measured GRFs at 1000 Hz. Peak and average GRFs and impulses in each plane were compared between limbs and groups. Prosthetic limbs generated reduced vertical impulses, braking forces and impulses, and mediolateral forces while generating similar propulsive impulses compared with intact and control limbs. Intact limbs generated greater peak and average vertical forces and average braking forces than control subjects’ limbs. These data indicate that the nonamputated limb experiences elevated mechanical loading compared with prosthetic and control limbs. This may place individuals with amputation at greater risk of acute injury or joint degeneration in their intact limb. Individuals with amputation adapted to running-specific prosthesis force production limitations by generating longer periods of positive impulse thus producing propulsive impulses equivalent to intact and control limbs.
A Six-Week Resistance Training Program Does Not Change Shear Modulus of the Triceps Brachii
Authors: Akagi Ryota , Shikiba Tomofumi , Tanaka Jun , Takahashi Hideyuki
Published: March 2016

We investigated the effect of a 6-week resistance training program on the shear modulus of the triceps brachii (TB). Twentythree young men were randomly assigned to either the training (n = 13) or control group (n = 10). Before and after conducting the resistance training program, the shear modulus of the long head of the TB was measured at the point 70% along the length of the upper arm from the acromial process of the scapula to the lateral epicondyle of the humerus using shear wave ultrasound elastography. Muscle thickness of the long head of the TB was also determined at the same site by ultrasonography used during both tests. A resistance exercise was performed 3 days a week for 6 weeks using a dumbbell mass-adjusted to 80% of the 1-repetition maximum (1RM). The training effect on the muscle thickness and 1RM was significant. Nevertheless, the muscle shear modulus was not significantly changed after the training program. From the perspective of muscle mechanical properties, the present results indicate that significant adaptation must occur to make the TB more resistant to subsequent damaging bouts during the 6-week training program to target the TB.
A calcium-redox feedback loop controls human monocyte immune responses: The role of ORAI Ca
2+
channels
Authors: Saul Stephanie , Gibhardt Christine S. , Schmidt Barbara , Lis Annette , Pasieka Bastian , Conrad David , Jung Philipp , Gaupp Rosmarie , Wonnenberg Bodo , Diler Ebru , Stanisz Hedwig , Vogt Thomas , Schwarz Eva C. , Bischoff Markus , Herrmann Mathias , Tschernig Thomas , Kappl Reinhard , Rieger Heiko , Niemeyer Barbara A. , Bogeski Ivan
Published: March 2016

Monocytes adjust deadly reactive oxygen species production by altering the subunit composition of the ORAI calcium channel.
Science Signaling
Podcast for 8 March 2016: Calcium signaling and ROS in monocytes
Authors: Bogeski Ivan , VanHook Annalisa M.
Published: March 2016

Redox-insensitive ORAI calcium channels enable monocytes to sustain calcium signaling while still producing bactericidal reactive oxygen species.
Focus Issue: The ins and outs of ORAI in immune cells
Authors: Gough Nancy R.
Published: March 2016

Understanding how ORAI activity is regulated will lead to a better understanding of immune cell function and diseases involving the immune system.
Papers of note in
Science Translational Medicine
Authors: Ferrarelli Leslie K.
Published: March 2016

This week’s articles describe how to enhance vaccine-induced immunosurveillance against glioma, how neurons might be spared following hemorrhagic brain injury, and how an activating mutation in the kinase SRC in bone marrow cells contributes to various pathologies.