bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simulative Study Into Injection Molding of Parts With Elastic Hinges by Applying Selective Heating
Authors: Mrozek Krzysztof , Poszwa Przemysław , Muszyński Paweł , Staniek Roman
Published: January 2018

In the conventional injection molding process a constant temperature of the mold is required depending on the type of injected polymer. Cooling process usually takes 2/3 of the entire production cycle time, so reduction of cooling time should lead to the decrease of the manufacturing cost. In practice, lower mold temperature can lead to the occurrence of the unwanted defects. The most common defects include short shots, diesel effect, visible weld lines, excessive internal stresses and warp. Those defects are more common and evident when injected parts are fitted with thin elastic hinges, where flow of the molten polymer through the very narrow channels causes the shear of polymer chains. In this work, a concept and simulative studies of selectively heated injection molds are presented. The idea of the novel technology is to heat only certain regions of the cavity where molten polymer cools down rapidly or where cavity cross-section is very narrow. It can be achieved with induction heating technology. The results showed that apart from the hinge geometry, the forming temperatures played an important role in shearing of polymer chains. The changes of analyzed parameters also influenced how material filled the cavity.
Pool Boiling Heat Transfer of Water on Copper Surfaces With Nanoparticles Coating
Authors: Cao Zhen , Preger Calle , Wu Zan , Abbood Sahar , Messing Maria E. , Deppert Knut , Sunden Bengt
Published: January 2018

Saturated pool boiling heat transfer is investigated experimentally on a copper substrate with copper nanoparticle coatings at atmospheric pressure, in terms of critical heat flux (CHF) and heat transfer coefficient (HTC). Experiments are carried out on the substrate surface with a diameter of 12 mm using DI water as the working fluid. The coating is formed by stacking copper nanoparticles generated by an aerosol method. The aerosol nanoparticles are generated by a spark discharge generator with nitrogen gas as carrier gas and size-selected prior to electrostatic deposition. The thickness of the coating is quantified by the deposition time. In the present study, copper particles with diameter 35± 5 nm are selected, considering better coverage on the surface, while the deposition time is controlled as 4h and 8h, respectively.

The boiling curves and heat transfer coefficient of MS-1 (4h deposition) and MS-2 (8h deposition) were compared with the BS (bare surface). The results show that CHFs of MS-1 and MS-2 are increased by 24% and 36%, respectively compared with the BS, while heat transfer is enhanced as well. High speed visualization tells that the coating provides more active nucleate sites and the hydrophobicity of the coating helps bubbles departure from the surface at low and moderate heat flux. At high heat flux, a hollow well occurs on MSs to supply liquid effectively to avoid dryout. Therefore, CHF and heat transfer are both improved.
Using Acoustic Waves to Modulate Stem Cell Growth and Differentiation
Authors: Maynard Jacqueline A. , Arabiyat Ahmad S. , Elefante Anna , Shearer Lucas , King Eoin , Kwaczala Andrea
Published: January 2018

During spaceflight, the loss of mechanical loads due to microgravity leads to rapid bone loss, where bone deteriorates at a rate of 1–2% per month, where some astronauts can lose as much as 20% of their skeletal mass in a single expedition [NASA, 2001]. In order to prevent muscle and bone loss, long-term space flight exercise regimes are strictly implemented [Shackleford, 2004]. Current research has demonstrated that mechanical vibrations can help to maintain or improve bone mass [Chan, 2013] and reduce adiposity [Chen, 2015, Sen, 2011] when signals are applied at the appropriate frequency and amplitude.

We have developed an acoustic sound chamber that can apply sound waves to stem cells grown in vitro. Characterization of the culture conditions inside the vibration chamber showed considerable variance across the culture plates where an applied acceleration of 0.6g varied at different spots in a 12-well tissue culture plate from as low as 0.47g to 0.78g. We believe the variance is caused by differences in the rigidity of the culture plates that makes the waves transmit inconsistently through the plastic. We hypothesized acoustic waves would induce osteogenic differentiation when applied to stem cells. We utilized pre-osteoblastic stem cells (MC3T3-E1-Subclone 4) to observe the effects of acoustic waves when applied at 0.3g and 0.6g, compared to non-vibrated controls. Cells were vibrated for 30 minutes a day for either 6 days (n = 24/group) or 12 days (n = 12/group). Cellular changes were characterized by assessing well-by-well cell number by a manual cell count and mineral content by Alizarin Red S staining. Differences between groups were determined using One-Way ANOVA with a post hoc test: Student’s t-test. To assess the effects of the variance across the culture plates, correlative analysis was conducted for well-by-well variation using Regression Analysis. Acoustically vibrated wells had 10x more cells after 6 days and showed more mineralization than non-vibrated wells at both 6 and 12 days. Acoustic waves have the ability to increase cell proliferation and can drive stem cell differentiation towards an osteoblastic lineage, this could lead to therapies that prevent bone loss during spaceflight.
Non-Linear Dynamic Analysis of a Cam With Flat-Faced Follower Linkage Mechanism
Authors: Yousuf Louay S. , Marghitu Dan B.
Published: January 2018

A mechanism with a cam and a flat-faced follower is considered for distinct angular velocities. The dynamic analysis presents follower linkage displacement driven by a cam rotating at a uniform angular velocity. The system has clearances between the flat-faced follower and the guides and the effect of clearance is analyzed. The cam-follower linkage mechanism is simulated using Solidworks program taking into account the impact and the friction between the cam, flat-faced follower, and the guides. The non-linear analysis tools are employed for the movement of the flat-faced follower. An experimental set up is established to capture the motion of the follower. High-resolution optical marker is mounted on the follower stem to capture the follower motion in the y-direction. The simulation and experimental results are compared and verified for largest Lyapunov exponent.
Friction Stir Welding of Aluminum 6061-T6 and Multi-Purpose Copper 11000 Alloy
Authors: Payton Lewis N.
Published: January 2018

Friction Stir Welding (FSW) is a solid-state joining process invented by The Welding Institute (TWI, United Kingdom) in 1991 in partnership with the National Aeronautics Space Agency. The process is emerging as one of the preferred alternative methods to permanently join materials that are difficult to join with traditional fusion methods (e.g., MIG, TIG, etc.). The welding of various copper alloys to various aluminum alloys is of great interest to the nuclear industry and the electrical distribution industry. The very different melting points of these two alloys preclude traditional fusion welding. Since the pin tool is simultaneously rotating and traversing through the work piece, flow around the tool is asymmetrical. This has led to designating one side of the tool as advancing and the opposite side as retreating. On the advancing side of the weld, the tool has a tangential velocity in the same direction as the weld is being created. The retreating side of the weld tool is the opposite. It can be can expected that asymmetric heating and deformation will occur in the weld due to this advancing/retreating nature of the FSW pin tool. Although previous studies have been performed that have observed this asymmetric behavior in both similar and dissimilar materials, the resulting welds have been of a poor quality. Large statistical experiments were conducted locally to study the effects of tool geometry, process parameters, and material composition have upon the friction stir butt welding of aluminum alloy 6061-T6 to copper alloy 11000 using a modern conventional 3-axis CNC vertical mill. The research seeks to determine (1) which direction a dissimilar metal friction stir weld between aluminum and copper should be executed, (2) the optimal shoulder diameter to be used when friction stir welding aluminum and copper on a CNC mill, and (3) the addition of a third material to act as an aide. The extensive statistical interactions between these parameters is also documented. A weld schedule was developed that resulted in an ultimate tensile strength (UTS) surpassing (greater than 90% of the weaker, more ductile copper alloy UTS strength) what has been documented in the current literature despite the machine limitations of the CNC vertical mill. Proper optimization of the welding schedule developed may approach 100 percent of the basic copper 11000 properties across the welded zone into the aluminum 6061-T6 alloy.
Creating a New Energy Efficiency Tool for Manufacturing Automation to Support Next Generation Sustainable Eco-Factories
Authors: Guerra-Zubiaga David A. , Newman Stephen
Published: January 2018

Global trends indicate that energy consumption in manufacturing automation is an important aspect to support next generation of sustainable eco-factories. Some manufacturing processes consume large amounts of energy to fully be automated. Researchers have been emphasizing the significant challenge energy generation will be in coming years to fulfill demand. Therefore, there is a need to explore new ways of reducing manufacturing automation energy consumption. This paper focuses on research concerned with energy consumption in a fully integrated manufacturing automation, and argues that the understanding of different approaches to explore novel tools for sustainable manufacturing is important to support eco-factories.
Local Entropy Generation in Large Eddy Simulation of Turbulent Reacting Flows
Authors: Safari Mehdi
Published: January 2018

Analysis of local entropy generation is an effective means to investigate sources of efficiency loss in turbulent combustion from the standpoint of the second law of thermodynamics. A methodology, termed the entropy filtered density function (En-FDF), is developed for large eddy simulation (LES) of turbulent reacting flows to include the transport of entropy, which embodies the complete statistical information about entropy variations within the subgrid scale. The modeled En-FDF contains a stochastic differential equation (SDE) for entropy which is solved by a Lagrangian Monte Carlo method. In this study, a numerical study has been done on effectiveness of SDE to model entropy variation using a partially stirred reactor (PaSR). This provides a computationally affordable case to compare different effects of entropy generation source terms and fine tune mixing coefficients. In this equation, turbulent mixing is modeled with Interaction by Exchange with the Mean (IEM). Combustion source terms are provided by direct integration of a GRI3.0 mechanism for methane/air system. Evolution of entropy was calculated from stochastic model and then compared with the one obtained directly by integrating the chemical mechanism. It was shown that results of both calculations have very good agreement versus different mixture fractions.
Development of an Innovative Coupling System for Industrial Vehicles: An AGV Oriented Approach
Authors: Pereira Davide , Machado José , Mendonça João Pedro
Published: January 2018

In this paper, authors explore the analysis and development of a innovative coupling system for industrial vehicles. After an introduction of the topic and the objectives, the advantages for developing such a system are described in detail. Some previously published studies with similar content or conclusions necessary to the understanding of the system under study are also presented.

In order to develop a system more precise than the currently used, the common systems are study in this paper, focusing on four wheeled trailers, varying the coupling system’s rotation center, which can be on the front or rear vehicles. In the commonly used systems the trailers tend to get too close from the rotation center, this means that both trailers have lower trajectory paths and not ideal precision.

Having studied the systems currently used in shop floor, a new coupling system is developed, with the aim of increasing trailers’ trajectory precision and manoeuver options. Two different systems were under study. The first one is to control the trailers steering mechanism, in order to position the trailer in a more precise position. The other system is simply altering the coupling system length and rotation centers. By analyzing both results, the solution with the rotation of the rear axle in each trailer guarantees better precision, where the trailers perform a trajectory precision of 100%. However, the solution that better fits the industrial reality is the solution with the alteration of the length and the rotation center of the coupling system. This solution allows less precision but its better in price, cost and implementation effort.
Experimental Study on Buoyancy-Induced Convection in Open Cell Aluminium Metal Foams
Authors: Rama Krishna Tupakula , Ghosh Moulic Sandipan , Bhattacharya Anandaroop
Published: January 2018

This paper presents the results of an experimental study on buoyancy induced convection in open cell aluminium foams attached to a one sided heated plate. The foam samples had porosity of around 90% and pore densities of 2, 4, 8 and 16 pores per cm. (PPC). The experiments were conducted under different orientations ranging from horizontal (heated from below) to vertical (heated from side). The heat transfer rates from the heater plate was measured and found to be a strong function of pore density and orientation as well as temperature gradient. In all the cases, the heat transfer rate was found to be superior to that of a vertical flat plate. For a given porosity and height the samples with larger pore sizes were found to be more effective. Finally the effective heat transfer coefficient was plotted in the form of Nusselt number as a function of Rayleigh number to capture its dependence on the foam geometry and boundary condition.
Fabrication for and Flow Visualization in 2.5D Rock-Based Ceramic Micromodels
Authors: Park Daniel S. , Upadhyay J. , Sharmin K. , Robbins J. F. , Schoegl I. , Thompson K. E. , Nikitopoulos D. E.
Published: January 2018

A ceramic-based micromodel was fabricated with batching of green alumina ceramics mixed with polymer binders, extrusion of the green alumina tapes, and hot embossing of the green tapes with a metal mold. The metal mold fabricated using optical lithography of SU8 and electroforming of nickel contained 2.5D pore network geometry in 13 layers of a rock, Boise sandstone. The hot embossing process enabled the generation of the pore network geometries with a minimum feature size of 25 μm and for distinct formation of the 13 layers of the 2.5D pore geometry of the rock. The green ceramic micromodels were processed with solvent extraction, thermal debinding, and sintering. The sintered micromodels showed significant shrinkages at all directions of the micromodels, which were 17.6% in x, 17.5% in y, and 14.6% in z. The sintered, 2.5D rock-based ceramic micromodel was capped with a thin glass cover slide and used for flow visualization with a fluorescent dye and fluorescent nano-particles. The dye-filled micromodel showed good flow connectivity and fluorescence signal intensity dependence on depth. It was observed that the peak particle concentration close to the observation window and gradual decrease in particle concentration along the depth. The higher velocities were measured in the low flow resistance region with velocity variations along the depth. The microfabricated 2.5D ceramic micromodels will allow resistance to harsh experimental conditions such as high temperature and pressure, and opportunity for investigation of the complex flow patterns in 3D.
An Integrated Parallelizable Algorithm for Computer Motion Simulation of Large-Sized Bio-Molecular Structures
Authors: Duan Shanzhong (Shawn)
Published: January 2018

In this paper, an integrated parallelizable algorithm is presented for computer simulation of dynamics of multibody molecular structures in polymers and biopolymers. The algorithm is developed according to an integrated O(N) simulation procedure developed by the author for calculating interatomic forces and forming/solving equations of motion for large-sized bio-molecular structures. Specifically, the simulation procedure is created via a proper integration between a parallelizable multibody molecular simulation method (PMMM) produced by the author and a parallelizable fast multipole method (PFMM). PFMM is utilized for calculation of atomic forces such as Van der Waals and Coulomb attractions between the atomics in the molecular structures. The parallelizable multibody molecular method is used for forming/solving equations of motion of large-sized molecular structures in polymers and biopolymers.

Currently, the calculation of interatomic forces and formation/solution of equations of motion are treated separately by various procedures. For instance, Fast Multipole Method (FMM) and Cell Multipole Method (CMM) are applied for calculating interatomic forces only. Cartesian Coordinate Method (CCM) and Internal Coordinate Molecular Dynamics Method (ICMM) have been introduced independently for forming/solving equations of motion. Though formation and solution of equations of motions, and atomic force calculations are needed for same molecular structure, there is no direct conversation between two group methods.

The proposed algorithm integrates multibody molecular method with fast multipole method in a parallel fashion so that both calculating atomic forces and forming/solving equations of motion can be carried out concurrently in a combined procedure. Computational loads associated with these two simulation tasks then can be divided among sub-chains, and each sub-chain is allocated to a processor on a parallel computing system via a proper integration between PFMM and PMMM. The algorithm can be used on both shared-memory and distributed-memory parallel computational systems. Compared with its counterpart of the integrated O(N) procedure developed by the author before, this algorithm has a computational complexity of O(logN) theoretically (N is number of subsets). The algorithm may find its applications for force calculation and motion simulation associated with large-sized molecular structures of polymers and biopolymers.
A Non-Intrusive Wearable Bio-Sensor Based Assistive Robotic System for Human Mental and Physical Intervention
Authors: Lansing Kyle , Yu Wei , Samanta Biswanath
Published: January 2018

Assistive robotics and technologies are going to play a vital role in our society. These platforms can support a level of human-robot interaction that is more meaningful, accommodating, and effective. This is especially true in the realms of medicine and rehabilitation, although assistive robots have a wider range of applications. In this work, using a non-intrusive wearable bio-sensor, a PC, and a mobile robot a novel proof of concept system has been developed that can detect human mental and physical states and intervene to promote mental and physical wellbeing. This study has utilized a skin-conductivity sensor to monitor changes in galvanic skin response (GSR) due to the presence of stress or anxiety along with a three-axis accelerometer to detect changes in physical activity levels. Two data processing algorithms have been developed to identify the mental and physical states by employing trend analysis techniques. By programming the system to obtain a baseline reading for individual subjects and comparing subsequent sensor values sustained changes in GSR levels due to stress can be detected. Similarly, by utilizing arrays and monitoring changes in accelerometer readings pattern changes associated with different physical activities can be detected. In addition, behaviors and motions aimed at alleviating human mental stress and physical inactivity have been developed by employing distraction and reminder intervention methods using a mobile robot. Experiments have been conducted on human subjects to evaluate the proposed robotic system’s capability to identify mental and physical states and intervene to improve their situation through participant responses. Based on the responses, a mean rating of 4.41 and 4.83 out of 5 has been given for the system’s ability to recognize human stress and physical state respectively. Additionally, participants have reported a mean of 30.3% reduction of stress and a mean of 23.3% increase in positive mood following the system’s intervention behavior.
Flow Visualization and 3D Measurements of Nano-Particle Transport in Rock-Based 2.5D Ceramic Micro-Models
Authors: Upadhyay Jagannath , Park Daniel S. , Sharmin Khurshida , Schoegl Ingmar , Thompson Karsten E. , Nikitopoulos Dimitris E.
Published: January 2018

Most flow visualizations and flow measurements to understand particle mobility in porous media are typically performed in transparent microfluidic devices (micro-models) with 2D pore-throat networks. Nano-particle mobility studies to date have been limited to micro-models made of transparent thermoplastic or silicone-based materials. In an effort to fabricate materials close to reservoir rock, ceramic micro-model has been designed and micro fabricated by our group to study nano-particle transport in rock-based ceramic micro-model. A Confocal Micro-Particle Image Velocimetry (C-μPIV) technique augmented with associated post processing algorithms [1] is used in obtaining 3D distributions of nano-particle velocity and concentration at selected locations of the ceramic micro-model. Furthermore, a novel in-situ, nondestructive method of measuring 3D geometry of non-transparent ceramic micro-model is described and validated. The particle experiment uses 860 nm fluorescence labeled polystyrene neutrally buoyant, and electrically neutral nano-particles. The data was acquired using confocal laser-scanning microscope to quantify 3D particle transport at selected observation locations. In addition, fluorescence microscope was used to measure in-situ geometry of porous media. Results of detailed 3D measurements of nano-particle velocity and particle concentration from experiment conducted at a constant flow rate of 30 nL/min in the rock-based micro-model are presented and discussed. Particle velocities range from 0 to 20.93 μm/sec in magnitude, and average concentration range from 6.02 × 103 to 6.79 × 103 particles at inlet channel while velocities range from 0 to 73.63 μm/sec and concentration range from 4.9 × 101 to 1.45 × 103 particles at selected observation locations of the ceramic micro-model. 3D velocity fields at selected locations also indicate that mean velocity closer to the top wall is comparatively higher than bottom wall, because of higher planar porosity and smooth pathway for the nano-particles closer to the top wall. The three dimensional micro-model geometry reconstructed from the fluorescence data can be used to conduct numerical simulations of the flow in the as-tested micro-model for future comparisons to experimental results after incorporating particle transport and particle-wall interaction models.
A Study on Adhesively Bonded Aluminum Plates Under Shock-Wave Loading
Authors: Yildiz Salih , Andreopoulos Yiannis , Jensen Robert E. , Shaffren Daniel , Jahnke Doug , Delale Feridun
Published: January 2018

Adhesive joint technology has been developed gradually, and the application fields of this type of joints have been expanded increasingly since they reduce the weight of the applications, provide uniform stress distribution across the joints, allow to bond similar, and dissimilar materials, and contribute to dampen the shock, and vibration. However, the performance of the adhesive joints under high loading rate such as blast or ballistic loading has been studied by few researchers. In this study, fully laminated plates consisting of 6061 aluminum plates (15” in diameter and 1/16” thick) and FM300K epoxy film adhesive were tested under shock wave loading. Full displacement field over the testing plates were obtained by TRC-SDIC technique, and the strain on the plates were computed by classical plate theory for large deflections. FEM model was analyzed and the results were compared with experimental results.
3D Printed Platforms to Facilitate Cell Culture on Carbon Nanotube Arrays
Authors: Kubrin Koby , Ahmed Adeel , Demiri Shkenca , Majid Maria , Dickerson Ian M. , Schrlau Michael G.
Published: January 2018

Template based chemical vapor deposition (CVD) is a process of effectively fabricating nanostructures such as Carbon nanotube arrays (CNT). During this process, a carbon-carrying precursor gas is used to deposit a layer of solid carbon on the surface of a template within a furnace. Template-based CVD using porous anodized aluminum oxide (AAO) membranes as the template has been applied to efficiently mass-produce CNT arrays which have shown promise for use in gene transfection applications. These AAO membranes are incredibly fragile, making them prone to cracks during handling which can compromise their performance. In order to ease handling of the CNT devices, three-dimensional (3D) printing has been applied to create a support structure for the fragile membranes. The work presented here focuses on the use of 3D printing as a means of integrating CNT arrays into nanofluidic devices, both increasing their useful application and preventing damage to the fragile arrays during handling. 3D printing allows the CNT arrays to be completely encapsulated within the fluidic device by printing a base of material before inserting the arrays. Additionally, 3D printing has been shown to create an adequate seal between the CNT arrays and the printed device without the need for additional adhesives or sealing processes. For this work, a commercially available, fused deposition modeling (FDM) 3D printer was used to print the devices out of polylactic acid (PLA) plastic. This approach has been shown to be effective and repeatable for nanofluidic device construction, while also being cost effective and less time consuming than other methods such as photolithography. Cell culture and has been demonstrated using HEK293 cells on the devices and was found to be comparable to tissue culture polystyrene.
Distributed Wind Energy Technologies: High Speed Scalable Epicyclic Gear Train Design
Authors: Menon Shruti Mohandas , Goudarzi Navid
Published: January 2018

Renewable energies are becoming increasingly favorite for grid connected and standalone applications. With recent concerns over climate change and global warming, the US department of Energy has implemented the use of alternative forms of energy with a target of 30 % energy production using renewable energy by 2025. However, there are certain disadvantages associated with the use of alternative forms such as intermittent energy generation, and high initial investment. This makes renewable energy less reliable leading to reluctance in adoption of these new technologies amongst consumers.

In this work, a high-speed scalable epicyclic gear train design is developed and studied analytically and numerically. An earlier developed Wind Tower Technology (WTT) is used as the case study for the gear train input parameters. Epicyclic gears are known to have advantages over parallel shaft drives in terms of weight, number of components, size, and power loss. These make epicyclic gear train a suitable choice for the WTT and similar concepts where an increase in the output shaft power in areas with low annual mean wind speed is required. The gear train configuration is designed based on the desired output speed and torque values, taking into consideration, the materials and the ease and novelty of machining and manufacturing. This work provides the preliminary analysis and results of developing this gearbox system for the WTT.
Study of Devolatilization Rates of Pine Wood and Mass Loss of Wood Pellets
Authors: Fraga Lelis , Silva João , Soares Delfim F. , Ferreira Manuel , Teixeira Senhorinha F. , Teixeira José Carlos
Published: January 2018

The present work investigates the mass loss of fine wood biomass using a TA INSTRUMENTS SDT 2960 simultaneous DSC-TGA instrument. The samples of sawdust were classified according to the grain size (< 0.063, 0.063–0.125, 0.125–0.25, 0.25–0.5, 0.5–1, and > 1 mm) and the micro samples were tested with air at a constant heating rate of 10 K/min, from the room temperature up to 800°C. From the results the kinetic properties of the biomass fuel were determined using the 1st order Coats-Redfern equation.

A transient thermal model of the fuel was implemented and was coupled with the biomass kinetic data in order to compute the mass loss of individual pellets and the results were compared with experimental data. The remaining mass, as fix carbon and ashes or unburnt substances, is approximately 3%. The kinetic parameters indicate that the biomass reactivity depends upon the particle size. The heating treatment of wood pellets at constant temperature and different time produced less nitrogen and more carbon and hydrogen for the short period of time.
Assistive Force Redirection of Crutch Gait Produced by the Kinetic Crutch Tip
Authors: Rasouli Fatemeh , Torres Alex , Reed Kyle B.
Published: January 2018

This paper investigates how crutch tip designs affect the user’s gait. Five Kinetic Crutch Tips (KCT), each with different durometers (i.e., stiffnesses) along with one carbon fiber reinforced nylon 3D printed KCT and one Standard Rubber Tip were tested. The first experiment examined eight healthy subjects to determine the assistive horizontal force generated and crutch angle range. The second experiment eliminates the human factor and uses a weighted crutch in free fall to investigate transitional angles between forward and backward motions. It was found that the KCT had a larger transitional angle than the Standard Rubber Tip. This increases the assistive forward forces of the crutch due to the surface kinetic shape of KCTs; however, the total angle of different crutch tips remains the same when used by the subjects. The assistive forces were present for the longest amount of time for the highest durometer KCT.
Applying Magnetic Consolidation Pressure During Cure to Improve Laminate Quality: A Comparative Analysis of Wet Lay-Up and Vacuum Assisted Resin Transfer Molding Processes
Authors: Pishvar Maya , Amirkhosravi Mehrad , Altan M. Cengiz
Published: January 2018

This paper presents the application of a new technique, Magnet Assisted Composite Manufacturing (MACM), to enhance the quality of composite laminates fabricated by wet lay-up/vacuum bag (WLVB) and vacuum assisted resin transfer molding (VARTM). Towards this goal, a set of high-power, Neodymium permanent magnets, which are placed on a magnetic tool plate, is applied on the vacuum bag/lay-up. To further demonstrate the effectiveness of MACM, six-ply random mat, E-glass/epoxy composite laminates are produced under four processing scenarios: (i) Conventional WLVB; (ii) WLVB with magnetic consolidation; (iii) Conventional VARTM; and (iv) VARTM with magnetic consolidation. Applying magnetic consolidation pressure is found to be a convenient and efficient method for enhancing the overall quality of the laminates fabricated by WLVB and VARTM. For instance, in WLVB-MACM process, fiber volume fraction improves by 98% to 49% and void content reduces from 5% to less than 1.5% compared to conventional WLVB. These two factors lead to substantially increased mechanical properties of the WLVB-MACM laminates to a level comparable to those achieved by the higher-cost VARTM-MACM process.
Haptic-Assisted Virtual Osteotomy As a Training Tool
Authors: Govea-Valladares Eder H. , Medellín-Castillo Hugo I. , García-Zugasti Pedro J. , Limon-Leyva Pablo A.
Published: January 2018

The maxillofacial surgery is a complex surgical procedure to correct facial malformations located in the head of the patient. A precise and reliable surgical planning is necessary for a successful maxillofacial surgical procedure. The experience and clinical practice of surgeons play a very important role during the surgical procedures. Modern Computer Aided Systems (CAS) have been developed in order to speed up the surgical planning process and to increase the accuracy and reliability of the surgical procedure. However, CAS systems have not been focused on their ability to train and to provide experience and clinical practice to novice surgeons or medical student. In this way CAS systems could be a potential tool to improve the skill of surgeons in order to decrease human errors in the maxillofacial treatment and surgical procedures.

This paper presents an investigation to evaluate the use of virtual reality and haptic systems as a training tool for maxillofacial surgeries, in particular osteotomies procedures. The aim is to evaluate the effect of virtual training on surgeon skills. Thus, a virtual osteotomy system has been developed and is presented. The system is based on an open source computer and programming resources, and makes use of haptic technologies to provide the users with the sense of touch. The virtual osteotomy procedures implemented are based on current surgical orthognathic surgery procedures. Free-form 3D manual cutting of bone is available in the system by means of the haptic device and the force feedback provided to the user, which increases the level of realism of the virtual procedure. The evaluation results show that the haptic-enabled virtual training of osteotomies increases the psychomotor skills of the practitioner, leading to an improved accuracy when carrying out the actual bone cut.
Dynamic Instability Analysis of a Cantilever Beam With Breathing Crack
Authors: Krishnaswamy Vigneshwaran , Pandey Manoj
Published: January 2018

In this paper, dynamic characteristics of a beam with breathing crack is considered. Breathing crack is modeled as a bilinear oscillator. The stiffness of the cracked beam is estimated by using influence coefficients based on castigliano’s theorem and strain energy release rate (SERR). The equation of motion of breathing cracked beam is formulated using finite element method using Hamilton’s principle. The equation of motion of breathing cracked beam is converted into Mathieu-Hill type equation to obtain the regions of dynamic instability of beam using Harmonic balance method and it is further solved for Eigen frequency of the cracked beam. The increase in breathing crack depth increases the instability region and it is found that the effect of the crack location near to the fixed end is more for the cantilever beam, and this also increases the instability region. It is found that increase in dynamic instability index increases the instability regions of the cracked structure. In addition to that, the effect of static and dynamic loads are also investigated and discussed. The study has been conducted for the first two instability boundaries of the cracked structure only. It is hence seen that assuming the crack to remain open underestimates the stability boundaries of the system. Permitting the crack to open and close (breath) yields a stability boundaries in between the open and uncracked beam.
Assessment of Dissimilar Weld Between Duplex Stainless Steel Grades for Severe Corrosive Applications
Authors: Paranthaman Venkatesan , Shanmuga Sundaram K.
Published: January 2018

This paper deals with the investigations on dissimilar weld between two duplex stainless steel grades AISI 2205 and AISI 2507. Increasing use of duplex stainless steel grades instead of austenitic stainless steel grades are growing day by day. This study is an effort in this direction in particularly focusing the dissimilar welding of super duplex stainless steel (AISI 2507) and commercial duplex stainless steel (AISI 2205) grades. Gas tungsten arc welding process was used in this study to fabricate the defect free weld plate. Microstructural analysis on dissimilar weld was carried out to study the diffusion of alloying elements. Micro hardness analysis, Charpy impact toughness test, tensile test and formability test were carried out and the properties were compared with their corresponding base metal properties. Hot corrosion test was carried out to study the feasibility of dissimilar weld in severe corrosive applications. The findings of this paper try to fulfill the applications where commercial duplex stainless steel grades are frequently gets affected in the weld region due to the severity of corrosive environments and due to the sacrificing weld properties.
Simulation of Magnetic Field Induced Current for Magnetic Seizure Therapy
Authors: Wadkar Abhijeet , Jupalli Prithvi K. , Asokanthan Samuel F.
Published: January 2018

Magnetic seizure therapy (MST) is currently on trial as an alternative to Electro-convulsive therapy (ECT) to treat patients suffering from treatment resistant depression (TRD). This paper is concerned with developing a deeper understanding of the mechanics behind MST by employing finite element analysis (FEA) of brain. To this end, a model that consists of concentric spherical layers that represent a realistic anatomical head model has been employed. Simulations performed via COMSOL Multi-physics helped identify the dimensions and coil types for the MST device as well as the angular probing orientations. Largest induced current due to the externally imposed magnetic field was found in the cerebrospinal fluid (CSF), which act as a barrier to induce current in the gray matter. Different copper coil configurations were experimented with namely the cap coil, stacked coil and the multi-stacked coil. These studies are envisaged to provide a quantitative approach to virtually simulate the MST procedure and hence enhance the benefits clinical trials that are currently underway.
Tuning Superhydrophilic Nanostructured Surfaces to Maximize Water Droplet Evaporation Heat Transfer Performance
Authors: Wemp Claire K. , Carey Van P.
Published: January 2018

Spraying water droplets on air fin surfaces is often used to augment performance of air-cooled Rankine power plant condensers and wet cooling tower heat exchangers for building air-conditioning systems. To get the best performance in such processes, the water droplets delivered to the surface should spread rapidly into an extensive, thin film and evaporate with no liquid leaving the surface due to recoil or splashing. This paper presents predictions of theoretical/computational modeling and results of experimental studies of droplet spreading on thin-layer, nanostructured, superhydrophilic surfaces that exhibit very high wicking rates (wickability) in the porous layer. Analysis of the experimental data in the model framework illuminates the key aspects of the physics of the droplet spreading process and evaporation heat transfer. This analysis also predicts the dependence of droplet spreading characteristics on the nanoporous surface morphology and other system parameters. The combined results of this investigation indicate specific key strategies for design and fabrication of surface coatings that will maximize the heat transfer performance for droplet evaporation on heat exchanger surfaces. The implications regarding wickability effects on pool boiling processes are also discussed.
Gold photothermal therapy: A positive for negative margins
Authors: Miller Miles A.
Published: January 2018

Nanoparticle-based photothermal therapy after tumor resection inhibits recurrence.
A tropical virus that prefers cool weather
Authors: Miner Jonathan
Published: January 2018

Cooler temperatures exacerbate chikungunya viral arthritis.
Draft Genome Sequence of
Brevibacillus
reuszeri
Strain NIT02, Isolated from a Laundered Rental Cloth Hot Towel
Authors: Sano Ken-Ichi , Anraku Asuka
Published: January 2018

Brevibacillus reuszeri
is a Gram-positive spore-forming bacterium. Here, we present the draft genome sequence of
Brevibacillus reuszeri
strain NIT02, which was isolated from a laundered rental cloth hot towel.
Draft Genome Sequence of
Prochlorococcus marinus
Strain XMU1401, Isolated from the Western Tropical North Pacific Ocean
Authors: Yan Wei , Zhang Rui , Wei Shuzhen , Zeng Qinglu , Xiao Xilin , Wang Qiong , Yan Hanrui , Jiao Nianzhi
Published: January 2018

Prochlorococcus marinus
is the most abundant photosynthetic organism in the tropical and subtropical oceans. Here, we report the draft genome sequence of
Prochlorococcus marinus
XMU1401, which was isolated from the Western Tropical North Pacific Ocean.
Genome Sequences of
Acholeplasma laidlawii
Strains with Increased Resistance to Tetracycline and Melittin
Authors: Baranova Natalia B. , Malygina Tatyana Y. , Medvedeva Elena S. , Boulygina Eugenia A. , Siniagina Maria N. , Dramchini Mohamed Amine , Prottoy Reshad Akbor , Mouzykantov Alexey A. , Davydova Marina N. , Chernova Olga A. , Chernov Vladislav M.
Published: January 2018

Acholeplasma laidlawii
is a well-suited model for studying the molecular basis for adapting mollicutes to environmental conditions. Here, we present the whole-genome sequences of two strains of
A. laidlawii
with increased resistance to tetracycline and melittin.
Draft Genome Sequence of
Lactobacillus fermentum
NCDC 400, Isolated from a Traditional Indian Dairy Product
Authors: Azmal Ali Syed , Kumar Sudarshan , Mohanty Ashok Kumar , Behare Pradip
Published: January 2018

We announce here the draft genome sequence of
Lactobacillus fermentum
NCDC 400, a potential probiotic strain isolated from a traditional Indian dairy product. The genome size of
Lactobacillus fermentum
NCDC 400 is 1.89 Mb, and the assembled sequence consists of 185 contigs joined into 138 scaffolds.
Efficacy of intensive multidisciplinary rehabilitation in Parkinson’s disease: a randomised controlled study
Authors: Ferrazzoli Davide , Ortelli Paola , Zivi Ilaria , Cian Veronica , Urso Elisa , Ghilardi Maria Felice , Maestri Roberto , Frazzitta Giuseppe
Published: January 2018

Objective

To evaluate whether a 4-week multidisciplinary, aerobic, motor-cognitive and intensive rehabilitation treatment (MIRT) improves the quality of life (QoL) of patients with Parkinson’s disease (PD), in the short-term and long-term period.

Methods

This is a prospective, parallel-group, single-centre, single-blind, randomised clinical trial (ClinicalTrials.gov NCT02756676). 186 patients with PD, assigned to experimental group, underwent MIRT; conversely, 48 patients, assigned to control group, did not receive rehabilitation. Parkinson’s Disease Questionnaire-39 was assessed 2 (T0), 10 (T1) and 18 (T2, only experimental group) weeks after the enrolment. We compared T1 versus T0 scores within subjects and delta scores (T1–T0) between subjects. To investigate the long-term effects, we compared T2 and T0 scores in the experimental group.

Results

At T0, no between-group differences in the Global Index Score (GBI) were observed (experimental group: 43.6±21.4, controls: 41.6±22.9, P=0.50). At T1, we did not find significant changes in controls (delta score: 1.2±9.9, P=0.23), and we found an improvement in GBI in the experimental group (delta score: −8.3±18.0, P<0.0001), significant also between subjects (P<0.0001). Comparing T2 versus T0 in the experimental group, the GBI maintained a significant improvement (delta score: −4.8±17.5, P<0.0001).

Conclusions

A rehabilitation treatment such as MIRT could improve QoL in patients with PD in the short-term and long-term period. Even though the single-blind design and the possible role of the placebo effect on the conclusive results must be considered as limitations of this study, the improvement in outcome measure, also maintained after a 3-month follow-up period, suggests the effectiveness of MIRT on the QoL.

Clinical trial registration

NCT02756676: Pre-results.
Experimental study of microbubble drag reduction on an axisymmetric body
Authors: Song Wuchao , Wang Cong , Wei Yingjie , Zhang Xiaoshi , Wang Wei
Published: January 2018

Microbubble drag reduction on the axisymmetric body is experimentally investigated in the turbulent water tunnel. Microbubbles are created by injecting compressed air through the porous medium with various average pore sizes. The morphology of microbubble flow and the size distribution of microbubble are observed by the high-speed visualization system. Drag measurements are obtained by the balance which is presented as the function of void ratio. The results show that when the air injection flow rate is high, uniformly dispersed microbubble flow is coalesced into an air layer with the larger increment rate of drag reduction ratio. The diameter distributions of microbubble under various conditions are submitted to normal distribution. Microbubble drag reduction can be divided into three distinguishable regions in which the drag reduction ratio experiences increase stage, rapid increase stage and stability stage, respectively, corresponding to the various morphologies of microbubble flow. Moreover, drag reduction ratio increases with the decreasing pore sizes of porous medium at the identical void ratio in the area of low speeds, while the effect of pore sizes on drag reduction is reduced gradually until it disappears with the increasing free stream speeds, which indicates that smaller microbubbles have better efficiency in drag reduction. This research results help to improve the understanding of microbubble drag reduction and provides helpful references for practical applications.
THE USE OF COMPUTATIONAL FLUID DYNAMICS IN THE OPTIMIZATION OF AIR-IMPEDANCE ELECTROSPUN STRUCTURES FOR TISSUE ENGINEERING
Authors: LAKTAS JACOB M. , GROWNEY KALAF EMILY A. , SELL SCOTT A. , MCQUILLING MARK W.
Published: January 2018

Electrospinning is a viable method for dermal tissue engineering scaffold fabrication. Grafts using air-impedance electrospinning possess the ability to significantly increase cellular infiltration. However, current air-impedance methods lack precise control over flow properties through the collecting mandrel and are unable to accurately control fiber deposition in an organized and well-distributed manner. This study focusses on the use of computational fluid dynamics (CFD) and its application to air-impedance structures to optimize the deposition of the resulting dermal graft. Air-impedance structures were created from a range of air pressures to determine the optimal pressure for fiber collection. Initial results showed a pressure of 11[Formula: see text]psi (1.3[Formula: see text]scfm), which led to increased cellular penetration, but created uneven structures. This inlet flow rate was implemented as the primary boundary condition for CFD simulations. CFD software was used to gather data on fluid flow characteristics for a variety of mandrel geometries. Results showed that a mandrel with increased length and offset pore geometry provided the highest uniformity of flow along the length of the model over the other mandrel lengths, geometries, and pore alignments based largely on pressure and velocity analysis. This mandrel was manufactured and used for validation of CFD data via scaffold analysis and cellular infiltration studies. Scaffold characterization confirmed a significant advantage in the creation of structures fabricated with the optimized air-impedance mandrel by effectively doubling the efficiency of production via larger usable scaffold area. The results indicate that CFD validation is a valuable technique to optimize air impedance scaffolds in silico and has proven to be a useful tool in the fabrication of tissue engineering scaffolds.