bluuebunny/crossref_metadata_2025 huggingface dataset:
Test Apparatus for Powered Saw Chain Systems
Authors: Otto Andrew W. , Parmigiani John P.
Published: April 2014

The emergence of battery operated landscaping equipment has driven increased scrutiny of the energy usage of such devices. Energy consumption is a primary design constraint for these new yard tools due to the low energy density of current battery technology compared to gasoline. Consumer battery-powered electric chain saws are an example. In order to provide both portability and usability the system’s power use must be understood in detail. Power use associated with cutting, friction, vibration, chip removal, and parasitic loads are all relevant entities in cutting system design. Interface friction between the cutting chain and bar as well as increases in cutting force due to chain vibration are of particular interest.

In this work, a test apparatus capable of determining the efficiency of cutting systems for use on chain saws is designed and constructed. Cutting power and frictional losses can be determined with the device under automated, user specified conditions. Operational parameters including chain velocity, feed velocity, and feed load may be used as feedback for device control. A universal mounting and drive system allows for testing with a wide range of off-the-shelf chains, bars, and drive sprockets. Input torque to the chain and reaction forces on the cutting media are recorded outputs which are used to analyze system efficiency. Preliminary work with the machine confirms trends found in existing research literature. Future research performed with the test apparatus will aid in new product design and enhance understanding of energy consumption in chainsaw cutting systems.
Effect of Swirl Intensity on Heat Transfer Characteristics of Swirling Flame Impinging on a Flat Surface
Authors: Singh Gurpreet , Chander Subhash
Published: April 2014

An experimental investigation has been carried out to determine the effect of swirl intensity on heat transfer characteristics of swirling flame impinging on a flat surface. The swirl intensity was varied by using helical vane swirlers having angles of 15°, 30° and 60° (low, medium and high swirl). Qualitative flame structures were studied by taking direct photographs of impinging flames. Experiments were conducted for different helical vane swirlers at different dimensionless separation distances (H/d = 1–6) for fixed value of Reynolds number (Re = 5000) and equivalence ratio (ϕ = 1.0). A dip in heat flux was observed at stagnation point for all levels of swirl. Peak heat flux was observed slightly away from the stagnation point due to centrifugal effect. A comparison of stagnation point heat flux has been done for different swirl intensities and for fixed operating conditions. Most uniform heat flux distribution was obtained corresponds to 30° helical vane swirler (medium swirl) at all separation distances.
CFD Research on Francis Pump-Turbine Load Rejection Transient Under Pump Condition
Authors: Zhou Daqing , Zhang Languo
Published: April 2014

In the paper, three dimensional unsteady CFD numerical method is established to simulate load rejection transient of Francis pump-turbine in pump mode. First, pumped storage power station’s whole flow system geometric model including diversion tunnel, surge tank, penstock, pump turbine unit and tailrace tunnel has been built and subdivided with prism and tetrahedral mesh. Then, three dimensional unsteady CFD simulation begins from the original steady pump condition, with the Realizable k–ε turbulent model. Through numerical calculation, the variation regularity of unit rotate speed, flow rate, torque, axial thrust and static pressure of measuring points with time are revealed during the load rejection transient. By comparison with experimental data, the changing regularity of transient dynamic parameters can be verified and their differences in the detail also can be reflected. Simultaneously, the phenomenon of water hammer has been captured by recording time-varying static pressure of measuring points. Furthermore, flow configuration in the passage undergoes very complex and unsteady change during load rejection transient.
Ground Vibration Test Planning of a Fighter Aircraft by Using a Rough Finite Element Model
Authors: Koksal Sertac , Yildiz Erdinc Nuri , Yazicioglu Yigit , Ozgen Gokhan Osman
Published: April 2014

Certification process is one of the crucial procedures for safety in the design of a new aerial platform. Flight flutter testing is the most critical component for the certification process. Usually a flutter analysis is performed beforehand for the planning of flight flutter testing of an aircraft which mostly requires the Finite Element Model (FEM) together with Ground Vibration Testing (GVT) to construct the structural dynamic model of the complete aircraft for the flutter analyses. GVT is not only required for new aircraft design but also when considerable changes are made to an existing aircraft or when new external load configurations are introduced. Experimental methods require high effort, high budget, long time, and much repetition. Therefore, the computational and theoretical studies seem more applicable in the early phase. However, GVT of an available fighter aircraft in defense projects becomes an issue for the designers if a detailed FEM of the aircraft is not available prior to test. Hence, planning of the GVT in early stage is vital for project leaders. In this study, a rough FEM of a fighter aircraft is developed and correlated to available GVT data for planning purpose. The representative mode shapes are evaluated by estimation of the several sections of the aircraft. It is also shown that a rough FEM of the aircraft can be utilized for determination of the measurement and excitation points on the aircraft in planning stage. The geometrical properties, physical limitations and basic requirements of GVT are also taken into account for an efficient planning.
Novel Nanofibrous Scaffold to Improve Wound Healing
Authors: Mak Eva Yi-Wah , Leung Wallace Woon-Fong
Published: April 2014

An antibacterial and biocompatible scaffold for fibroblasts proliferation based on chitosan has been developed. Chitosan solution is electrospun into uniform fibers of 100–200 nm in diameter that mimic the extracellular matrix of human skin. The fibrous mats are successfully cross-linked to be stable in acidic solution, which can be used to treat acute wounds. The crosslinked fibrous mats display antibacterial properties toward Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. The mechanical properties of fibrous mats are shown to be comparable to native skin dermis which protects the skin wound.
Enhanced Electrical and Mechanical Properties of Nanotube Reinforced Composites
Authors: Pal Kaushik , Kim Jin Kuk
Published: April 2014

Halloysite nanotube (HNT) and clay were introduced into the composites to improve the dispersion of MWNT. Combining the nanotubes with HNT/clay allows both electrical and mechanical behavior to be simultaneously enhanced with the addition of HNT and clay, dielectric property is also increased tremendously. MWNTs appear to have an affinity for clay that causes them to become more exfoliated and better networked in these composites.
A Computational Model for Predicting the Temperature Distribution Inside a CVD Reactor for Carbon Nanotube Synthesis
Authors: Raji K. , Sobhan C. B.
Published: April 2014

Chemical Vapor Deposition (CVD) is the cheapest method among various synthesis techniques of Carbon Nanotube (CNT). However, an optimal design of CVD systems encounters a lot of challenges due to the complexity of the reaction process and the energy interactions involved. Optimal designs can be evolved only on the basis of a good theoretical analysis of the CVD system, solving the governing equations of the physical phenomena, to predict the conditions inside the furnace. The work reported here investigates the reacting flow dynamics and temperature distributions inside the CVD reactor during the formation of carbon nanotubes. The theoretical approach solves the momentum and energy equations, in conjunction with the reaction kinetics involved. The mathematical model is numerically solved using a two dimensional CFD formulation, utilizing the COMSOL Software. The flow velocities, temperature distribution and local heat transfer inside the reactor are obtained from the analysis. It is concluded from the investigation that a considerable variation exists between the local temperature inside the reactor, at regions near the catalyst container, and the furnace wall temperature. The results obtained can provide important input information for a complete simulation of the CNT synthesis process, for the optimal design of the CVD system.
Multi-Physics Analyses of Articular Cartilage and Subchondral Bone by Using Micro-CT and MPM Measurement Based Model
Authors: Fukatani K. , Mizuta R. , Morita Y. , Sakamoto H. , Nakamachi E.
Published: April 2014

The articular cartilage and subchondral bone are modeled by using μ-CT and MPM measurement results for multi-physics analyses, which employed the conventional finite element code for the solid continuum and particle method — SPH — for the liquid continuum. The articular cartilage at the micro-scale consists of the chondrocyte, the extracellular matrix-collagen fiber, the proteoglycan and the intercellular fluid and modeled by using MPM observation results. The subchondral bone consists of the trabecular bone and the intercellular fluid, and these are modeled by using μ-CT measurement results. Both are remodeled by the cyclic stress caused by the joint movement such as walking and jogging. Especially, the flow of intercellular fluid causes the shear stress on the chondrocyte cell in the articular cartilage and on the bone cell in the trabecular bone. Therefore, the flow and stress analyses of both the articular cartilage and subchondral bone are strongly required. In this study, the multi-physics analyses combined with finite element and particle methods are carried out to investigate the stress stimulation on the chondrocyte cell and the surface of trabecular bone. For the solid phase analyses by using finite element code, the nonlinear viscoelastic constitutive model was introduced for collagen fiber, the elastic model for the trabecular bone. For the fluid phase analyses by using SPH code, the viscosity model was introduced for intercellular fluid.
Systems Generating Electricity Through Expansion of Natural Gas: Effect of the Ambient Temperature to the Performance
Authors: Morosuk T. , Tsatsaronis G. , Tesch S.
Published: April 2014

This paper discusses the thermodynamic performance of three different system configurations used to expand natural gas from a pressure of above 40 bar to a final pressure of approximately 12 bar: (1) System in which all natural gas passes through a throttling valve, (2) system that uses only an expander as the expansion device, and (3) system using in parallel both an expander and a throttling valve as expansion devices. The sensitivity analysis demonstrates how the mass flow rate of natural gas and the seasonal fluctuation of the ambient temperature affect the thermodynamic efficiency of these systems.
Effect of Alloying Elements on Creep and Fatigue Damage of Ni-Base Superalloy Caused by Strain-Induced Anisotropic Diffusion
Authors: Suzuki Ken , Sano Tomohiro , Miura Hideo
Published: April 2014

In order to make clear the mechanism of the directional coarsening (rafting) of γ′ phases in Ni-base superalloys under uni-axial tensile strain, molecular dynamics (MD) analysis was applied to investigate effects of alloying elements on diffusion characteristics around the interface between the γ phase and the γ′ phase. In this study, a simple interface structure model corresponding to the γ/γ′ interface, which consisted of Ni as γ and Ni3Al as γ′ structure, was used to analyze the diffusion properties of Ni and Al atoms under tensile strain. The strain-induced anisotropic diffusion of Al atoms perpendicular to the interface between the Ni(001) layer and the Ni3Al(001) layer was observed in the MD simulation, suggesting that the strain-induced anisotropic diffusion of Al atoms in γ′ phase is one of the dominant factors of the kinetics of the rafting during creep damage. The effect of alloying elements in the Ni-base superalloy on the strain-induced anisotropic diffusion of Al atoms was also analyzed. Both the atomic radius and the binding energy with Al and Ni of the alloying element are the dominant factors that change the strain-induced diffusion of Al atoms in the Ni-base super-alloy.
Innovative Designs for the Suspension System of Horizontal-Axis Washing Machines: Secondary Suspensions and Tuned Mass Dampers
Authors: Argentini T. , Belloli M. , Robustelli F. C. , Martegani L. , Fraternale G.
Published: April 2014

Cabinet vibrations during spinning cycles of washing machines are often perceived negatively by customers, both in acoustic and visual terms. Therefore, in a market that is more and more oriented towards customer satisfaction and appliance efficiency, reducing cabinet vibrations and noise is a very attractive target.

Previous experimental campaigns have highlighted that currently installed dry-friction dampers have highly non-linear characteristics and they are the main source of broadband forcing on the cabinet panels. To overcome these negative effects, two innovative designs for the suspension system have been studied and are here presented: the first solution is a secondary suspension system, designed to filter out the high frequency force components introduced by the dampers and therefore to mitigate panel vibrations; the second solution is more radical and it consists in removing the existing dampers and to substitute them with a tuned mass damper (TMD), directly fixed to the oscillating group. These solutions are a compromise between cost and efficiency, since a linear oil damper would impact excessively on the final cost of the appliance.

The secondary suspension system has been designed to meet the very strict requirements of the manufacturer: low cost (which implies small mass) and applicable to the existing machine without any modification of any part other than the dampers themselves. The desired results have been achieved increasing the mass of the damper rod and introducing a fixed-fixed (or hinged-hinged) beam spring. The prototype of the secondary suspension has been tested independently and assembled in the washing machine, and the vibratory and acoustic results will be reported.

The introduction of a TMD and the contextual removal of the dry-friction dampers, on the contrary, requires the modification of the oscillating group in order to work efficiently. As a matter of fact, a principle for the design of oscillating groups is the space optimization, which usually leads to asymmetric distributions of mass of the oscillating group, that in their turn lead to asymmetrically coupled mode shapes. This dynamic characteristic does not suit the design of a simple and compact TMD, with a limited number of degrees of freedom. We show that careful mass distribution and a specifically designed 2-dofs TMD can efficiently substitute the original dampers. An elemental prototype of the so defined TMD has been tested on a shaking table, and it seems an effective alternative to classical suspension systems.
Design, Simulation and Development of Gold Microneedles Patch
Authors: Tayyaba Shahzadi , Ashraf Muhammad Waseem , Afzulpurkar Nitin , Khaleeq ur Rahman Muhammad
Published: April 2014

Technological advancements are essential for all fields of life particularly in health discipline to test and analyze the biological and biomedical samples. Biological micro electromechanical system (Bio-MEMS) based healthcare technologies are handy to make human life comfortable and snug by ease of use, eradicating pain, reducing risk of diseases, improving diagnosis process and treatments techniques. In this study the design, simulation and development of piezoelectricaly actuated microfluidic device (gold needle patch) has been presented. The simulation of skin insertion using gold needle into skin to study the effects of skin piercing and optimize the design of needle has been conducted in ansys autodyne by making 3D model with applied force 0.4 to 0.9 N at the tip area of needle. The microfluidic analysis of 3×3 microneedle patch has been carry out in ansys workbench using computational fluid dynamic (CFX) environment. The maximum velocity 2.015 e4 m/Sec has been achieved. After the successful development of gold needles patch, the fluid transport and insertion test of piezoelectricaly actuated patch also has been conducted using chicken skin.
Tribological Behaviour of Hot Extruded Al6061-Si3N4 Composite
Authors: Chinnakurli Suryanarayana Ramesh , Khan Saleem , Koppad Praveennath G. , Khan Zulfiqar
Published: April 2014

Silicon nitride (Si3N4) possesses excellent hot hardness, wear resistance coupled with good corrosion resistance. Further, it possesses high anti friction properties making it an ideal reinforcement in developing high quality light weight, metal matrix composites for tribological applications. Silicon nitride has been successfully dispersed in aluminum alloy matrices. Their tribological properties with the beneficial effect of silicon nitride in enhancing the wear resistance of metal matrix composite have been reported by several researchers. Most of the researchers have focused on development of silicon nitride reinforced aluminum composite by powder metallurgy and casting route. However, meager information is available as regards the secondary processing of these composites in particular hot extrusion. Several researchers have reported an improved tribological behaviour in composites after extrusion. Hot extrusion of light weight metal matrix composites is very challenging. In the light of the above, this paper discusses the tribological behaviour of hot extruded Al6061 aluminum composites, which were initially developed by stir casting technique. Nickel coated silicon nitride particles were dispersed in Al6061 alloy using stir casting process. The cast composites were extruded at an extrusion ratio of 1:10 adopting a temperature of 550°C. The hot extruded composite (6Wt% Si3N4) and the matrix alloy were subjected to metallographic studies, microhardness and friction and wear tests using a pin on disc machine. Friction and wear test were carried out at loads ranging from 10 to 60 N at a sliding velocity of 0.314m/s. The worn surfaces and wear debris analysis have been carried out to understand the mechanism of wear in the developed hot extruded composites. The developed hot extruded composites exhibited lower coefficient of friction and wear rates when compared with matrix alloy.
Effect of Anisotropic Strain Field on the Electronic Conductance of Carbon Nanotubes
Authors: Ohnishi Masato , Suzuki Ken , Miura Hideo
Published: April 2014

Since carbon nanotubes (CNTs) have unique electronic and mechanical properties, there have been many efforts to develop CNTs-based electronic devices and sensors. The authors have also validated the possibility of a highly sensitive strain sensor using popular resin in which multi-walled CNTs (MWNTs) were dispersed uniformly. It is, however, indispensable for clarifying how to change the electronic state of a deformed CNT for assuring the stable performance of the sensor because the reported sensitivity has ranged widely. In this study, the relationship between the deformation characteristic of a CNT under strain and its electronic properties was analyzed. The analysis result obtained from density functional theory (DFT) calculation showed that the orbital hybridization was occurred when the maximum local dihedral angle exceeded 10–20° and 25–30° in GNRs and CNTs, respectively, which induced the band gap.
Development of Force-Feedback Technology for Training Clinicians to Deliver Manual Cervical Distraction
Authors: Gudavalli Maruti Ram , Yadav Vikas , Vining Robert , Seidman Michael , Salsbury Stacie , Morgenthal Paige , Patwardhan Avinash , Goertz Christine
Published: April 2014

Objective: Neck pain is a prevalent musculoskeletal (MSK) complaint and costly societal burden. Doctors of chiropractic (DCs) provide manual therapies for neck pain patients to relieve discomfort and improve physical function. Manual cervical distraction (MCD) is a chiropractic procedure for neck pain. During MCD, the patient lies face down on a specially designed chiropractic table. The DC gently moves the head and neck in a cephalic direction while holding a gentle broad manual contact over the posterior neck, to create traction effects. MCD traction force profiles vary between clinicians making standardization of treatment delivery challenging. This paper reports on a bioengineering technology developed to provide clinicians with auditory and graphical feedback on the magnitude of cervical traction forces applied during MCD to simulated patients during training for a randomized controlled trial (RCT).

Methods: The Cox flexion-distraction chiropractic table is designed with a moveable headpiece. The table allows for long axis horizontal movement of the head and neck, while the patient’s trunk and legs rest on fixed table sections. We instrument-modified this table with three-dimensional force transducers to measure the traction forces applied by the doctor. Motion Monitor software collects data from force transducers. The software displays the magnitude of traction forces graphically as a function of time. Real-time audible feedback produces a steady tone when measured traction forces are <20N, no tone when forces range between 20–50N, and an audible tone when forces exceed 50N. Peer debriefing from simulated patients reinforces traction force data from the bioengineering technology.

Results: We used audible and graphical feedback to train and certify DCs to apply traction forces to the cervical spine of simulated patients within three specific ranges. This technology supports a RCT designed to assess the ability of clinicians to deliver MCD within specified force ranges to patients randomized to different force dosages as an intervention. Future applications may include training chiropractic students and clinicians to deliver the MCD treatment.
First-Principle Dynamic Modeling of a Linear Micro-Compressor
Authors: Alzoubi Mahmoud , Li Guanqiu , Zhang TieJun
Published: April 2014

Compressor is the main component in the Vapor Compression Cooling cycle (VCC). Comparing with scroll and screw compressors, linear compressors are used in miniature-scale VCC cycle for small and portable applications such as electronics cooling systems. Linear micro-compressors exhibit high performance because they have fewer moving components and less frictional losses than other types. In this paper, a first-principle dynamic model has been developed to characterize the transient pressure, temperature, and fluid flow inside a linear micro-compressor. A theoretical analysis and a parametric study have been performed in this research to reveal the influence of the piston motion profile on the pressure and temperature changes inside the compression chamber. Moreover, the effect of changing piston velocity on the flow rate, pressure and temperature trends has been studied in this research.
Thermorheological and Magnetorheological Effects on Rayleigh-Bénard-Marangoni Convection in Ferromagnetic Liquids With Non-Uniform Basic Temperature Gradient
Authors: Narendra Sekhar Gummadi , Gopal Jayalatha , Revanna Prakash
Published: April 2014

A linear stability analysis of buoyancy and surface tension driven convection in temperature and magnetic field sensitive Newtonian ferromagnetic liquid is studied. The importance of this problem lies in the interesting possibility of regulating convection using a heat source (sink). The problem discussed in this paper leads to a situation that the basic temperature gradient here is non-uniform. The governing equations thereby are of variable coefficients. The principle of exchange of stabilities is shown to be valid. The critical values are obtained using higher order Galerkin technique. The influence of various magnetic and nonmagnetic parameters on the onset of convection has been analyzed. It is found that there is tight coupling between Rayleigh and Marangoni numbers, with an increase in one resulting in a decrease in the other. Variable viscosity parameter and heat source destabilize the system. The effect of heat sink is to stabilize the system. Buoyancy magnetization parameter destabilizes the system both in presence/absence of heat source/sink.
Kinematics, Dynamics and Vibration Models for 3RPR Parallel Kinematics Manipulator
Authors: El-Khasawneh Bashar , Alazzam Anas
Published: April 2014

Parallel link manipulators are the type of mechanisms that have closed kinematics chains. Some of their advantages over open kinematics chains (called also serial kinematics manipulators) are their high stiffness and accuracy. This paper carries out forward and inverse kinematic and dynamic analysis on a certain type of parallel kinematic mechanisms. This is needed to conduct vibration analysis on the same platform. The type of mechanism is planar 3 RPR manipulator. This entails identifying the modes of the manipulator. A simplified vibration theoretical model is derived. This derivation helps in the optimization of parallel kinematics machine design for improved/optimized dynamic performance. The implications of dynamic stiffness modeling should reflect on better noise rejection, less chatter during machining, and increasing the bandwidth of such mechanisms to admit running at higher speeds.
Fabrication and Characterization of Micro-Patterned Magnetorheological Elastomeric Structures
Authors: Yashaa Ammar S. , Manoochehri Souran
Published: April 2014

This paper presents fabrication and characterization of micro-patterned magnetorheological elastomeric structures composed of magnetorheological fluid (MRF) sandwiched with magnetorheological elastomeric (MRE) materials. The MRE structures are made of polydimethylsiloxane (PMDS) with and without an additive of carbonyl iron (CI) particles with a size range of 6–9 um and the MRF is composed of silicon fluid mixed with the CI particles of the same size range. Three different SU-8 master molds of plain, longitudinal, and latitudinal patterns are constructed. Also, four MR elastomeric structures of different CI particle arrangements of isotropic MRE, anisotropic top-to-bottom-aligned MRE, anisotropic side-to-side-aligned MRE, and pure PDMS for each SU-8 master mold are fabricated. MRE structures are then characterized by using a tensile testing machine under a normal condition (off-state) and a low magnetic field condition (on-state). The tensile tests were performed to experimentally investigate their tunable properties. Later, the data gathered are compared for different conditions.
Water Supply Sustainability Indicators for the Southern California-Baja California Area
Authors: Gil Samaniego Ramos Margarita , Campbell Ramírez Héctor Enrique , Tapia Olivas Juan Carlos
Published: April 2014

Southern California and Baja California share, besides a dynamic social and economic exchange and 226 kilometers of borderline, an important natural resource: water from the Colorado River. Both areas have arid and semiarid climate in large zones and local fresh water sources are scarce, so water imports from the Colorado are strategic for their continued social and economic growth.

Southern California’s water supply comes from the State Water Project, the Colorado River Aqueduct and local sources; in turn, Baja California depends mostly on the water supplied by the Colorado River, with an aqueduct that serves the Pacific coastline cities of the state. Both water supply systems are considered high energy consumers, affecting the quality of life in the region.

The sustainable development of both communities is a challenge to Mexican and American public policy planners who must recognize that, to meet the future water demands to support sustainable development in this area it will require improved utilization and management of water resources.

In this paper, water supply sustainable indicators were calculated for southern California and Baja California to evaluate and compare their performance towards sustainability. Findings show big differences in the indicators like water use per person, percentage of the cost of water relative to household income, cost of electricity to convey water, etc. High contrast in both economies makes up for these differences, but as water stakeholders of an only source, that is, the Colorado River, Mexico and the United States should avoid those imbalances in water use and management efficiencies, as it might affect its availability and cost, bringing potential conflicts and disturbing the traditional friendly coexistence and growth of both communities.
Optimization Methodology for Innovative Automotive Crash Absorbers
Authors: D’Agostino Luca , Bertocchi Luca , Splendi Luca , Strozzi Antonio , Moruzzi Patrizio
Published: April 2014

The simulation of vehicle crash impacts requires accurate and computationally expensive Finite Element analysis. An effective procedure consists in considering and establishing which improvement can be made on an equivalent sub-model of the full vehicle. In this way, all the analysis can be performed on smaller models, thus saving computational time. A full vehicle simulation is required only at the end of the design process to validate the results of the sub-model analysis.

A software based on a genetic optimization algorithm has been developed in order to optimize the geometrical parameters of a variable-thickness crash absorber. A numerical study on the folding of thin-walled aluminum tubes with variable-thickness has been performed in order to achieve the maximum energy absorption-to-mass ratio. Moreover, the performance in terms of folding length and crush load peaks have been considered.

Different optimization strategies have been implemented to find out which solution guarantees the achievement of the optimization target with the lowest computational cost.

The results show how the approach proposed by the authors allows an efficient variable-thickness crash absorber to be obtained. In fact it performs better in term of crash behavior and energy dissipation-to-mass ratio, with respect to the original constant_thickness model.
Hand Gestures in CAD Systems
Authors: Tumkor Serdar , Esche Sven K. , Chassapis Constantin
Published: April 2014

When designing products, networked computers are increasingly used to facilitate the collaboration among team members from remote locations. Design visualization plays a critical role in understanding the design concepts shared by the design team members. CAD systems have 3D visualization capabilities that are designed to help users to understand complex structures easily and to design better products. However, 3D visualization on a 2D screen has limitations in communicating complex structures. Furthermore, gestures play a significant role in face-to-face communication but are missing in remote collaboration. Object manipulation in 3D using gestures in the real physical space without a cumbersome hand-held peripheral device may ease the visualization and understanding of the concept model. Today, peripheral devices for human-computer interfaces are not only becoming more advanced but also less expensive. Some of the game controllers are now equipped with depth cameras (RGB-D cameras) and have a great potential for complementing or even replacing the traditional keyboard and mouse interface with hand or body gestures. In this paper, new low-cost mixed reality devices for 3D user inputs and visual outputs are investigated and their possible uses with CAD systems in the process of collaborative design are discussed.

In this study, a hand tracking system built based on two Kinect sensors has been used to track the position and orientation of the user’s hands. In this system, CAD models can be manipulated and disassembled using hand gestures. The new user interface provides for a user-friendly interaction between designer and CAD system.
Comparison of Theoretical and Experimental Corn Drying Profiles Within a Cross-Flow Column Dryer
Authors: Mattison Lars M. , Suess Taylor N. , Twedt Michael P. , Gent Stephen P.
Published: April 2014

This study compared the drying characteristics of corn within a continuous flow dryer under a variety of operating conditions. The tests were completed on a pilot scale cross flow corn dryer with variable fan speed and column thickness. The dryer column has a height of 3.35 m (132 in.), width of 0.61 m (24 in.) and variable thicknesses ranging from 0.30–0.36 m (12–14 in.). In addition, the drying air temperature and air flow rate per volume of grain were varied. An array of thermocouples measured the thermal profile of the corn bed within the dryer. The dryer exhaust was divided into four zones, each 0.83 m (33 in.) tall. Each zone measured incoming air velocity and exhaust temperature and relative humidity. Using these measured values in conjunction with the known ambient conditions, the theoretical amount of moisture removed from each zone was calculated. Corn dryer efficiency and throughput are becoming increasingly important, as it is the second largest cost associated with corn production. Improved farming practices, in conjunction with improved corn genetics, have resulted in increased yields and the ability to grow corn in locations not possible two decades prior. The overarching goal of this research is to help determine the key factors which help to dry corn more efficiently.
Composite Materials in Automotive: Improving Safety by Refining FEA Correlation
Authors: Miscia Giuseppe , Bertocchi Enrico , D’Agostino Luca , Baldini Andrea , Dolcini Enrico , Narducci Angelo
Published: April 2014

In the last few years, the restrictive safety standards and the need for weight reduction have brought the crashworthiness research to focus on composite materials because of their high energy absortion-to-mass ratio. On the other hand, the possibility of obtaining predictive dynamic FEA models for these new materials is still an open issue: the present work aims at developing a methodology for the characterization of composite materials with particular interest for the head impact simulation.

Composite materials behavior, defined through the mathematical models implemented in FEA codes, is very complex and requires a large amount of physical and numerical setting parameters. The majority of these parameters can be obtained by an experimental campaign that involves several kind of different tests. The presented methodology allows to obtain a good numerical-experimental correlation simply performing few tests which emulate the behavior of the component during the head impact event.

A software tool based on a genetic optimization technique has been developed in order to determinate automatically the material properties values that guarantee the best numerical-experimental correlation.
Overall Structure Control for Product Design Using Geometric Skeleton Based on Functional Decomposition
Authors: Guo LianShui , Zhou Xuan , Zhao Lian , Liu Qingming
Published: April 2014

Product conceptual design derives from the functional requirement initially, and the overall structure control for product design is one of the most difficult problems being addressed in CAD modeling.

The objective of this investigation is to present a framework on rapid modeling using rules and mechanism library for mapping between functions and mechanism structures. In this paper, it is shown that the overall structure can be achieved largely by using multi-level parametric skeleton model. In order to drive the conceptual design into a more detailed design, the intelligent master model is presented to realize the parametric feature modeling and design knowledge reuse.

The main contribution of this paper is that an integrated framework has been developed to design assembling tools of satellite by using a necessary auxiliary wizard. The case studies presented demonstrate the potential significance of this work for a wide range of engineering design problems.
Advanced Traction Control System for Motorbikes
Authors: Castillo Juan J. , Cabrera Juan A.
Published: April 2014

Traction control systems are a fundamental active safety equipment of vehicles; they control wheel slip when excessive torque is applied on driving wheels, helping the driver to bring the vehicle under control and improving handling and stability when starting or accelerating and especially under poor or slippery road conditions. The aim of this work is to develop a parameter estimation block for further development of an intelligent traction control system. To evaluate the performance of the proposed estimation algorithm, estimated variables are compared making use of BikeSim 2.0 ®. Parameter estimation was performed using an extended Kalman filter optimized using genetic algorithms. Using an artificial neural network, the slip that maximizes the tire-road friction coefficient is identified.
Potential Utilization of Higher Alcohols in Unmodified Diesel Engine
Authors: Kumar Naveen , Bansal Sidharth , Vibhanshu Vipul
Published: April 2014

India does not have large reserves of crude petroleum and spends a huge amount of foreign exchange for importing crude petroleum. The environmental degradation caused by burning of petroleum derived fuels is also causing an ecological imbalance. Research is carried world over on renewable fuels which could either be used as an extender or substitute to petroleum origin fuels and in this context alcohols such as ethanol and butanol have an immense potential. The earlier work on use of alcohols as a blend with diesel in the compression ignition engine has suggested reduction in emissions, however, problems such as phase separation and increase in fuel consumption has also been encountered while utilizing ethanol in diesel engines. To alleviate this problem, isobutanol has the potential to be used along with ethanol to make a homogenous blend without any phase separation and simultaneous advantage of alcohol being an oxygenated fuel which shall improve the combustion and reduce emission. The present study was carried out to explore the potential utilization of ethanol-isobutanol-diesel blends (containing up to 20% ethanol-isobutanol mixture in equal proportions) in compression ignition engine. Three blends were prepared having 5%, 10%, 20% ethanol-isobutanol mixtures respectively and calorific value, kinematic viscosity; specific gravity and density of blends were found to decrease with increase in ethanol-isobutanol percentage. The engine trial was conducted on an unmodified diesel engine to evaluate the performance and emission characteristics on ethanol-isobutanol-diesel blends and results were compared with baseline data of diesel. The results obtained from the engine trial suggested that brake thermal efficiency (BTE) increased and brake specific energy consumption (BSEC) decreased for the blends and considerable reduction in carbon monoxide (CO) and carbon dioxide (CO2) was observed with blends with a small increase in unburnt hydrocarbon (UBHC). The nitrogen oxide (NOx) and smoke emissions were also found to reduce for the ethanol-isobutanol-diesel blends.
A DOE- and Kriging-Based Model for Studying on the Dynamics of Multibody Mechanical Systems With Revolute Joint Clearance
Authors: Zhang Zhenhua , Xu Liang , Flores Paulo , Lankarani Hamid M.
Published: April 2014

Over the last two decades, extensive work has been conducted on dynamic effect of joint clearances in multibody mechanical systems. In contrast, little work has been devoted to optimizing the performance of these systems. In this study, analysis of revolute joint clearance is formulated in term of a Hertzian-based contact force model. For illustration, the classical slider-crank mechanism with a revolute clearance joint at the piston pin is presented, and a simulation model is developed using the analysis/design code MSC.ADAMS. The clearance is modeled as a pin-in-a-hole surface-to-surface dry contact, with appropriate contact force model between the joint and bearing surfaces. Different simulations are performed to demonstrate the influence of the joint clearance size and the input crank speed on the dynamic behavior of the system with the clearance joint. An innovative design-of-experiment (DOE)-based method for optimizing the performance of a mechanical system with the revolute joint clearance for different ranges of design parameters is then proposed. Based on the simulation model results from sample points, which are selected by a Latin hypercube sampling (LHS) method, a polynomial function Kriging meta-model is established instead of the actual simulation model. The reason for development and use of the meta-model is to bypass computationally intensive simulations of a computer model for different design parameter values in place of a more efficient and cost-effective mathematical model. Finally, numerical results obtained from two application examples, considering the different design parameters, including the joint clearance size, crank speed, and contact stiffness, are presented for further analyzing the dynamics of the revolute clearance joint in a mechanical system. This allows for predicting the influence of design parameter changes, in order to minimize contact forces, accelerations, and power requirements due to the existence of joint clearance.
A Method for Applying High Cyclic Strain to Focal Adhesions and Measuring the Cell Response
Authors: Shiraishi Toshihiko , Ohara Takuya , Morishita Shin
Published: April 2014

This paper describes a method by which broadband cyclic strain can be applied to focal adhesions of a cell. In recent years, evidence has been growing that focal adhesions act as mechanosensors of cells which convert mechanical force into biomechanical signaling. However, there are no effective methods by which mechanical stimulation with high frequency can be directly applied to each focal adhesion. Here we develop a micropillar substrate embedding micron-sized magnetic particles and enabling the micropillars to be deflected by external magnetic field. The combination of long and short micropillars produces the difference of deflection between them and enables the micropillars to apply strain to a cell. We verified that the micropillars responded to external magnetic field up to at least 25 Hz without phase difference. Using the magnetic micropillar substrate, we observed the cytoskeletal deformation of an osteoblast cell. The findings indicate that the present micro device can be used for investigating mechanosensing systems of a cell.
Multiphase Flow Simulation of Water-Entry and -Exit of Axisymmetric Bodies
Authors: Nguyen Van-Tu , Ha Cong-Tu , Park Warn-Gyu
Published: April 2014

A fully-compressible, multiphase, homogeneous mixture model, based on unsteady Reynolds-averaged Navier-Stokes equations is presented in this study. Dual-time preconditioning method was employed to improve the computational efficiency of the solution. The multiphase flow solver has been applied to computations of: (1) cavitating flows over underwater projectiles; (2) transonic flow past an underwater projectile; (3) water impact of a circular cylinder entering the water; (4) water-entry of a hemisphere with one degree of freedom; and (5) supercavitating flows over an axisymmetric projectile during water-entry and water-exit. The surface pressure coefficients, water impact forces, vertical accelerations, and impact velocities are compared with available experiments and other published results. Good agreements with those results are obtained. Aspects of water-entry and water-exit flow physics of a projectile with and without gaseous exhaust plume including cavity shape, phase topography and drag coefficients are presented.
Application of Arlequin Framework for the Numerical Simulation of Rotating Machinery
Authors: Nouri-Baranger Thouraya , Torkhani Mohamed , Altmeyer Guillaume
Published: April 2014

Rotating machinery are a place where specific vibrating phenomena take place, due to particular loadings, rotating effects and damping. Numerous numerical simulation of rotating machinery are based on the use of costless beam models. These models are however insufficient to represent localized non-linear phenomena. In these zones, 3D models are more adapted to accurately represent the effects of contact or cracks. Their cost is however prohibitive for industrial applications. In this paper, development of a method coupling 1D and 3D models is proposed to simulate advanced dynamic of rotating machinery.

The bases of Arlequin method, allowing multi-model/multi-scheme connecting the different zones by a superposition technique, are developed and applied to the simulation of contact between rotor and stator. Specific operators are introduced, such as gyroscopic matrix, angular acceleration matrix and centrifugal stiffening one.
Flight Opportunities for Testing and Demonstrating Emerging Space Technologies
Authors: Maclise Douglas (Dougal) C. , Mains Richard C. , van Dijk Alexander
Published: April 2014

NASA’s Flight Opportunities Program has two primary goals — provide flight opportunities to be used to mature new technologies and foster the new commercial space industry. Since 2010 the Program has contracted with seven commercial flight providers and has flown over 18 campaigns that carried over 45 technology payloads. The flight opportunities are awarded through an open competitive solicitation called the Announcement of Flight Opportunities (AFO) or through other NASA solicitations for new technology development. To date over 100 technologies have been selected for flight testing. This paper profiles four examples of the technologies that have been tested or demonstrated on suborbital flights: 3-D Printing in Space developed by Made In Space Inc., Fine Water Mist Portable Fire Extinguisher developed by ADA Technologies and NASA/Glenn Research Center, Precision Landing Exploration Technology developed by Draper Labs, and On-orbit Propellant Storage Stability developed by Embry-Riddle Aeronautical University.
Lattice Boltzmann Modeling of Ultrafast Laser Heating on Metal Film
Authors: Wang Dadong , Ma Yanbao
Published: April 2014

Lattice Boltzmann method based on Boltzmann transport equation is developed to simulate the nanoscale heat transport in metal film. The Boltzmann transport equation is applicable to describe both electron and phonon scattering processes: the absorption of photon energy by electrons and the subsequent heating of metal lattice (phonons) through electron-phonon collisions. We show that the Boltzmann transport equation can give rise to the well-known two-temperature model. To validate our numerical tool, ultrafast laser heating on metal film is analyzed by lattice Boltzmann method and finite difference method based on two-step model separately, and exactly the same results are obtained. The predicted transient reflectivity changes agree with picosecond laser heating experiments data also.
Modeling and Simulation of Microscale Bipolar Particle Dynamics in an Applied Electric Field
Authors: Hossan Mohammad Robiul , Dillon Robert , Dutta Prashanta
Published: April 2014

The colloidal dynamics of bipolar microparticles is of growing theoretical interest in understanding and advancement of electrorheology and ferroelectric research. In this paper we present an interface resolved numerical study to analyze dynamics of ellipsoidal bipolar microparticles for various initial configurations. The bipolarity is imposed by providing surface charges of opposite polarity at the two ends of ellipsoidal particles. The numerical simulations show that in the absence of an external electric field, ellipsoidal particles form a head-to-tail chain or stay apart from each other depending on the inter-particle distance, as well as the magnitude and direction of the inherent polar moment. On the other hand, in presence of an external electric field, the assembly or clustering mechanism primarily depends on the magnitude and direction of the applied electric field. Simulation results also show that the electrorotation process is a function of initial configuration. This comprehensive numerical study will help to better understand the mechanisms of clustering, string formation, and the disaggregation of bipolar microparticles.