bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Response of a Rigid Foundation Subjected to a Distance Blast
Authors: Ojetola Deji , Hamidzadeh Hamid R.
Published: October 2013

Blasts and explosions occur in many activities that are either man-made or nature induced. The effect of the blasts could have a residual or devastating effect on the buildings at some distance within the vicinity of the explosion. In this investigation, an analytical solution for the time response of a rigid foundation subjected to a distant blast is considered. The medium is considered to be an elastic half space. A formal solution to the wave propagations on the medium is obtained by the integral transform method. To achieve numerical results for this case, an effective numerical technique has been developed for calculation of the integrals represented in the inversion of the transformed relations. Time functions for the vertical and radial displacements of the surface of the elastic half space due to a distant blast load are determined. Mathematical procedures for determination of the dynamic response of the surface of an elastic half-space subjected to the blast along with numerical results for displacements of a rigid foundation are provided.
Experimental Comparison of Different Diesel-Biodiesel Blends in a CFR Engine
Authors: Zamboni G. , Marelli S. , Marmorato G. , Capobianco M.
Published: October 2013

A wide experimental investigation was performed on a CFR engine with a view to comparing different renewable fuels in terms of Cetane Number, engine brake thermal efficiency and exhaust emissions.

The CFR engine available at the Internal Combustion Engines Group of the University of Genoa was properly modified and fully instrumented in order to control operating conditions and to measure the average engine parameters and in-cylinder pressure diagrams.

Aiming at the comparison of fuels obtained from various feedstock, an experimental procedure was then defined, including the standard Cetane Number evaluation and the definition of engine operating quantities in 16 different working points, considering four levels of rotational speed and load, for fixed levels of compression ratio and injection advance.

Methyl-esters of rapeseed oil and of vegetable oils mix were investigated, while rapeseed, palm and coconut oil were also available. Several blends, obtained by mixing different biodiesel fractions with conventional diesel oil, assumed as reference fuel, were tested applying the defined experimental procedure.

In the paper the experimental setup is firstly presented describing changes and instrumentation of CFR engine. The investigation program is then summarized in order to introduce results discussion, mainly focused on the analysis of the influence of the biodiesel content on brake thermal efficiency, NOx and soot emissions, taking into account fuel properties.
Experimental Investigation of a Desiccant Wheel Cycle
Authors: Al-Alili Ali , Hwang Yunho , Radermacher Reinhard
Published: October 2013

In hot and humid regions, removal of moisture from the air represents a considerable portion of the air conditioning load. Conventionally, air conditioning systems have to lower the air temperature below its dew point to accomplish dehumidification. Desiccant air conditioners offer a solution to meet the humidity and temperature requirements of buildings via decoupling latent and sensible loads. In this work, the performance of a new desiccant material is investigated experimentally. This desiccant material can be regenerated using a low temperature heat source, as low as 45°C. It also has a unique S-shape isotherm. The effects of the process air stream’s temperature and humidity, the regeneration temperature, the ventilation mass flow rate, and the desiccant wheel’s rotational speed on the cycle performance are investigated. ARI-humid conditions are used as a baseline and the moisture mass balance is maintained within 5%. The results are presented in terms of the moisture removal rate and latent coefficient of performance (COPlat). The results show a desiccant wheel’s COPlat higher than unity when it is coupled with an enthalpy wheel.
Effectiveness of Fractal Orifices for Flow Measurement
Authors: Fester Veruscha , Ntamba Ntamba Butteur , Rust Francois , Slatter Paul , Noble-Jack Ian
Published: October 2013

There is data available in the literature showing that more accurate flow measurement of air can be obtained using fractal-shaped orifice plates. Furthermore, energy losses over the fractal orifices were less than for circular orifices of the same area. The design of energy efficient systems is becoming increasingly important, therefore the testing of fractal orifices with fluid systems is of great interest. This present study determined pressure loss and discharge coefficients for both Newtonian and non-Newtonian fluids, for fractal shaped orifices plates.

Four short orifices, circular, triangular (0-generation), 1st generation and 2nd generation Von Koch fractal-shaped, were manufactured. The orifice plates had the same flow area as the circular orifice of equivalent diameter Deq = 26.2 mm (β = 0.57). This work provides novel experimental results on the performance of fractal orifices for Newtonian and non-Newtonian liquid flow applications. Flow measurement energy conversion efficiency of some 19% can be expected when using the fractal orifices over the standard circular geometry.
Effective NEMS Education and Training in an Undergraduate Course
Authors: Barakat Nael , Jiao Heidi
Published: October 2013

Increasing demand on workforce for nanotechnology implementation has resulted in an exponential increase of demand on educational material and methods to qualify this workforce. However, nanotechnology is a field that integrates many areas of science and engineering requiring a significant amount of background knowledge in both theory and application to build upon. This challenge is significantly magnified when trying to teach nanotechnology concepts and applications at the undergraduate engineering level. A considerable amount of time is needed for an undergraduate engineering student to be able to design and build a useful device applying nanotechnology concepts, within one course time.

This paper presents an actual experience in teaching hands-on applications in nanotechnology to undergraduate engineering students through an optimized model, within a normal course time. The model significantly reduces the time needed by undergraduate students to learn the necessary manufacturing techniques and apply them to produce useful products at the micro and nano levels, by ensuring that infrastructure and legwork related to the educational process are partially completed and verified, before the course starts. The model also provides improved outcomes as all its pre-course work is also tested with students working under different arrangements of professors’ supervision. The result is an optimized infrastructure setup for micro and nanotechnology design and manufacturing education, built with students in mind, to be completed within the frame of one semester course.

The model was implemented at GVSU-SOE as the core hands-on part of a senior undergraduate course titled (EGR 457 nano/micro systems engineering). Students in the course were able to go through the design and build steps of different MEMS and NEMS products, while learning and utilizing cleanroom equipment and procedures. This was based on infrastructural arrangements by students preceding this class by a semester and working closely with the professors. Assessment was conducted on both sides of the model and results were collected for evaluation and improvement of the model.
Pulsed Laser Deposition and Biocompatibility of Titanium Nitride Coatings
Authors: Haywood Talisha M. , Darkwa Kwadwo M. , Gupta Ram K. , Kumar Dhananjay
Published: October 2013

TiN thin films were deposited on pure titanium (99.9 %) and stainless steel (316L) substrates using the pulsed laser deposition (PLD) technique. PLD is a very versatile technique to deposit high quality films and it allows the stoichiometry transfer of a multi-component system from target to deposited film. The crystallographic orientation of the films was studied using the X-ray diffraction technique and the results showed that the films were polycrystalline with the (111) preferred orientation. The hydrophilic/hydrophobicity nature of the films was investigated using contact angle measurements and the results indicated that the TiN coated surfaces were hydrophilic (< 90°). Biocompatibility of the TiN thin films was characterized in terms of cell attachment of bone cells on the surfaces of the coatings. Human bone marrow stromal cells were cultured, seeded, stained and imaged using a fluorescent microscope. Results on the biological behavior of the TiN thin films suggest that TiN is a good biocompatible material and has great promises in biological applications.
On the Role of Radiation in Low Density Silicon Carbide Foams
Authors: Tseng Charles C. , Sikorski Ruth L. , Viskanta R. , Chen Ming Y.
Published: October 2013

There are a variety of foams that can be used in thermal protection and/or thermal insulation systems. At high temperature (> 1000 K) thermal radiation may be important or dominate heat transfer in a foam; however, studies based on more detailed thermal radiation analysis are limited. In this paper foams are considered to be semitransparent, because radiation can penetrate through the pore (or void) space and/or foam skeleton (ligament), depending on the materials from which the foams are made. Of particular interest of this study is to understand how the properties of foam material such as its density, mean cell size, etc. affect the radiative transfer through silicon carbide (SiC) foams. In the paper, the dimensionless strut diameter is considered an important parameter of foams, and the radiative properties of the foams are analyzed by Mie scattering theory. The attenuation/extinction behavior of SiC foams can be considered as a function of the dimensionless strut diameter of the foam. The results reveal that the foam properties can significantly reduce radiative heat transfer through the high temperature foam used for the thermal protection.
Investigating the Structural Properties of Corn Stover Biomass
Authors: Ozdemir Ozan C. , Gent Stephen P. , Suess Taylor N. , Delfanian Fereidoon
Published: October 2013

The purpose of this study is to analyze structural material properties of biomass materials, namely corn stover. The microstructure of the biomass is examined by using a nano-hardness testing machine (NANOVEA®). The goal of this analysis is to test the hardness and elasticity of individual fibers using nanoindentation and to develop testing techniques to perform this task. The results of the stated tests are statistically analyzed. The measured structural properties of the biomass have the potential to be used in computer simulations for structural analysis and bulk solid flows. The bulk fluid motion of the pulverized/chopped biomass can be simulated in storage and transportation equipment, including auguring screws and pneumatic conveyance systems, as well as devices for feeding biomass feedstocks in biorefineries. Traditional biochemical and thermochemical reactors operate as batch systems because of the difficulty of feeding the biomass feedstock in a continuous manner. Having a clearer background about the structural and rheological properties of biomass feedstock will help simulate and design the bulk-solid flows within storage bins and conveyance systems.
Combustion Synthesis and Characterization of Porous NiTi Intermetallic for Structural Application
Authors: Vanterpool J. , Ilegbusi O. J. , Khatami N.
Published: October 2013

This paper describes experimental investigation of thermal and combustion phenomena as well as structure for self-propagating combustion synthesis of porous Ni–Ti intermetallic aimed for structural biomedical application. The objective is to correlate processing conditions with structure for the porous material. Ni–Ti mixture is prepared from elemental powders of Ni and Ti. The mixture is pressed into solid cylindrical samples of 1.1 cm diameter and 2–3 cm length, with initial porosity ranging from 30% to 42%. The samples are preheated to various initial temperatures and ignited from the top surface such that the flame propagates axially downwards. The flame images are recorded with a motion camera as well as the temperature profile. The samples were then cut using a diamond saw in both longitudinal and latitudinal directions. Image analysis software was then used to analyze the porosity distribution in each sample. The porosity distribution was then systematically correlated with the input processing conditions.
Peridynamic Simulation of Damage Evolution for Structural Health Monitoring
Authors: Littlewood David J. , Mish Kyran , Pierson Kendall
Published: October 2013

Modal-based methods for structural health monitoring require the identification of characteristic frequencies associated with a structure’s primary modes of failure. A major difficulty is the extraction of damage-related frequency shifts from the large set of often benign frequency shifts observed experimentally. In this study, we apply peridynamics in combination with modal analysis for the prediction of characteristic frequency shifts throughout the damage evolution process. Peridynamics, a nonlocal extension of continuum mechanics, is unique in its ability to capture progressive material damage. The application of modal analysis to peridynamic models enables the tracking of structural modes and characteristic frequencies over the course of a simulation. Shifts in characteristic frequencies resulting from evolving structural damage can then be isolated and utilized in the analysis of frequency responses observed experimentally. We present a methodology for quasi-static peridynamic analyses, including the solution of the eigenvalue problem for identification of structural modes. Repeated solution of the eigenvalue problem over the course of a transient simulation yields a data set from which critical shifts in modal frequencies can be isolated. The application of peridynamics to modal analysis is demonstrated on the benchmark problem of a simply-supported beam. The computed natural frequencies of an undamaged beam are found to agree well with the classical local solution. Analyses in the presence of cracks of various lengths are shown to reveal frequency shifts associated with structural damage.
Burr Size Minimization When Drilling 6061-T6 Aluminum Alloy
Authors: Zedan Y. , Niknam S. A. , Djebara A. , Songmene V.
Published: October 2013

The burr formation mechanisms strongly depend on the machining methods as well as cutting conditions. Cutting fluids play significant roles in machining, including reduction of friction and temperature. Using a cutting fluid, however, degrades the quality of the environment and increases machining costs. In the present work, initially the effects of cutting fluid application (dry, mist and flood) and their interaction with cutting parameters on the burr size during drilling of 6061-T6 aluminum alloys were investigated using multi-level full factorial design. Second-order non-linear mathematical models were developed to predict burr height for various lubrication modes. The accuracy of the regression equations formulated to predict burr height when using different lubrication modes has been verified through carrying out random experiments in the range of variation of these variables. A procedure was developed to minimize burr size for drilling holes by presenting the optimal levels of process parameters. Taguchi optimization method based on L9 orthogonal array design of experiment was then used which has shown very accurate process parameters selection that leads to minimum burr height. According to experimental study, it was observed that dry and mist drilling can produce parts with quality comparable with those obtained in wet drilling when using the optimal cutting conditions. In addition, increase in cutting speed and feed rate exhibits a decrease in burr size.
Analytical and Experimental Investigations of the Effect of Temperature Gradient on Rock Failure
Authors: Li Jun , Guo Boyun , Ai Chi
Published: October 2013

Drilling fluids injected into geothermal and oil and gas borehole create a temperature gradient in rock near the bottom hole. This temperature gradient is more pronounced in underbalanced drilling (UBD) with gaseous fluids due to Joule Thomason cooling effect at the drill bit. The effect of the temperature gradient on rock failure was investigated analytically and experimentally in this study. The result indicates that the temperature gradient can significantly promote rock failure during drilling. The rate of penetration (ROP) increased by 22.4% on average as the temperature differential increased from 30°C to 180°C in the Chagan Sandstone from the Tamuchage Basin, Mongolia. This explains high ROP, hole enlargement, and hole deviation in gas UBD operations. Although the test done at very small scale may not be representative to the real drilling conditions, the result supports the analytical model developed in this work, which can be used for optimizing drill bit and fluid injection rate in geothermal and oil and gas well drilling.
Developing Installations and Activities for an Interactive Light Studio at the American Sign Language and English Lower School
Authors: Baglione Melody , Short Dale , Correll Caitlin , Tan David
Published: October 2013

Students from The Cooper Union for the Advancement of Science and Art created new installations and activities for an Interactive Light Studio for pre-kindergarten students at The American Sign Language and English Lower School (P.S. 347) in New York City. The studio creates ways for both deaf and hearing students to explore light and sound while simultaneously promoting science and technology to students at a young age. Improvements to the studio in the 2011–12 school year strove to further the educational mission of the project while introducing new and exciting interactive multimedia installations. A digital projection system was created using easily assessable sensors, electronics, and open-source computer software creating an interactive play and learning environment that encourages self-driven discovery. The project engages young children, including minorities, girls, and disabled children, in active science learning while providing Cooper Union students with an opportunity to work on a real world project in their community.
Heat Transfer Enhancement of Laminar Internal Flows Using Electrically-Induced Swirling Effect
Authors: Lakeh Reza Baghaei , Molki Majid
Published: October 2013

A computational and experimental approach is conducted to enhance the convective heat transfer in fully developed laminar flow in parallel-plates configuration. Laminar internal flows are associated with unchanging Nusselt number along the channel due to the fully developed condition of the boundary layer. Inducing a swirling effect along the flow can disturb the flow field and enhance the convective heat transfer from the plates to the flow. The interaction between an electrically-induced secondary flow and the pressure-driven main flow complicates the flow field and causes a swirling effect. In this study, the electric field governing equations are solved numerically using finite volume method. In order to obtain a proper boundary condition for the charge density, an experimental setup was utilized to measure the time-averaged corona current. The distribution of electric field and charge density on the cross section of the channel is obtained and adopted to find the electric body-force at each point. The flow field computations are performed with FLUENT CFD code on a three-dimensional model using second-order upwind scheme. The secondary flow field is imposed on the cross section of the channel by corona discharge. An array of emitting and receiving flat electrodes are embedded in the parallel plates to induce a corona jet on the cross section of the channel. The axial component of velocity along with an array of corona jets gives birth to a swirling flow which can significantly enhance the convection coefficient and Nusselt number in the fully developed regime. This investigation indicated that the convective heat transfer can be enhanced up to 173% with an applied potential of 24 kV.
Effects of Side-Face Carburizing, Face Width, Tempering and Intergranular Oxidation on Bending Fatigue Strength of Case-Carburized Gear
Authors: Miyachika Kouitsu , Maeta Norimasa
Published: October 2013

The hardness measurements of hardened layer, the observation of intergranular oxidation with the SEM and the bending fatigue test for gas and vacuum case-carburized spur gears were carried out, and then profiles of hardened layer, case depth, amount of intergranular oxidation and S-N curves were obtained. Effects of the case depth, the side-face carburizing, the face width, the tempering and the intergranular oxidations on the bending fatigue strength were determined.
Bending Fatigue Strength of Innovative Gear Materials for Wind Turbines Gearboxes: Effect of Surface Coatings
Authors: Gorla Carlo , Rosa Francesco , Concli Franco , Albertini Horacio
Published: October 2013

In order to better exploit the available resources, wind turbine size is constantly increasing: the need of bigger gearboxes is an obvious and immediate consequence of this evolution tendency. The traditional manufacturing methods exhibit some difficulties for a mass-production of such large and high quality gears. The aim of the XL-Gear research project is to identify an alternative gear manufacturing procedure. This procedure mainly relies on the selection of innovative and adequate materials to manufacture the gears. Two innovative materials (Jomasco and Metasco) have been identified. A common gear material has been selected to define a baseline from which variations can be evaluated. In addition, the effects of a thermal spray tungsten carbide coating on the base material will be also investigated. In the first part of this research project, the bending resistance is evaluated, while, in the second part, the pitting resistance will be evaluated. In order to assess to bending strength, adequate gear geometry has been designed and some parts manufactured with the above mentioned materials. These gears have then been used to perform STF (Single Tooth Fatigue) bending fatigue tests. In the paper, the STF test procedure design and set-up will be described and the STF tests results on the baseline and coated gear will be presented and discussed.
Numerical Study of Heat and Mass Transfer in Evaporating Multiple Droplets Composed of Binary Mixture of Ethanol and Iso-Octane
Authors: Banerjee R. , Gopinath R.
Published: October 2013

Fuel injection and mixing is extremely important for efficient combustion in an IC engine. In order to develop an effective droplet evaporation model for such applications, evaporation from the surface of multiple droplets has been considered in this study. Droplets are composed of a binary mixture of ethanol and iso-octane. Numerical study has been performed using commercially available CFD software Ansys Fluent 13.0. Liquid/gas interface of the droplets was tracked using VOF multiphase model. As ethanol and iso-octane form a highly non-ideal mixture, vapour-liquid-equilibrium (VLE) calculations were made using UNIFAC group contribution method. Source terms arising due to interfacial mass transfer are implemented in the continuity, momentum, energy and species equations. VLE calculations and source terms for the various transport equations were implemented using user defined subroutines.
Development of a Particle Sizing Algorithm for Sub-10µm Particles Using Shadowgraphy
Authors: Robinson Michael , Mahmud Zakaria , Swenson Orven F. , Hoey Justin
Published: October 2013

We developed a Small Particle Sizing Algorithm (SPSA) that utilizes Fresnel and Fraunhofer diffraction profiles to determine sizes of small spherical particles from 1 to 10 μm in diameter. The SPSA uses standard shadowgraphy techniques to generate an image of the diffraction profile from which two characteristic parameters are measured, image size and image slope. Over specified ranges, the combinations of these parameters are unique, enabling the simultaneous calculation of particle size and distance from the object plane of the CCD camera.
Influence of Bonding Pressure on the Mechanical Properties of Copper Bumps
Authors: Nai S. M. L. , Lu H. J. , Cheng C. K. , Wei J.
Published: October 2013

Thermocompression bonding is one of the key ways to form interconnections in many hetegrogeneous devices. The quality of metallic joints formed using thermocompression is predominantly determined by the bonding temperature and pressure. In order to achieve a strong and reliable joint, metallic joints in particular copper, which has an oxidative nature, require a high bonding temperature (> 300 °C). However, thermomechanical-related stresses induced during bonding can compromise the performance of the interconnections in the long term. Thus, one way to manage this is to lower the bonding temperature used in forming the interconnections. In this study, copper-copper bonding is successfully demonstrated at a bonding temperature of 80 °C. In order to better understand the effect of bonding pressure on the joint’s performance, the mechanical properties of the individual bulk copper bumps are evaluated using the nanoindentation system. Studies are conducted on the bulk copper bumps subjected to different bonding pressures. Their corresponding yield strength and hardness results are then determined. It is observed that as the applied bonding pressure increases, the mechanical properties of the bulk copper bump reach a certain threshold value and beyond which, properties start to degrade. The microstructure and grain sizes of the copper bumps are also analyzed using the electron backscatter diffraction.
Effect of Wall Cooling With Condensation on Depressurization of a Steam-Prefilled Chamber
Authors: He Pengfei , Zhu Chao , Du Fen , Ji Zhiming , Lin Chao-Hsin
Published: October 2013

Depressurization can be realized by condensing saturated vapor of a pure substance inside a thermodynamically-closed system such as a confined chamber. The depressurization rate depends directly upon the effectiveness of cooling to the condensing vapor. This study is to investigate the transient characteristics of heat and mass transfer during the condensation-controlled depressurization process. Specifically, the objectives of the study include the transient changes in pressure, temperature and their distributions within the chamber. The representations of pressure and temperature in terms of the corresponding in-situ measurements are also of utmost interest. To this end, this study adopts a research methodology of combined modeling-simulation-experiment approaches, including (1) a pseudo-thermodynamics model to provide the limiting characteristics of depressurization and a quick parametric analysis, (2) a full-field numerical simulation to explore the phase non-equilibrium in momentum and heat transfer, (3) an experimental system to provide measurements for model validations, and (4) a heat transfer model to interpret the transient relationship between thermocouple measurements and vapor temperatures. Our study shows that the pressure in chamber is almost uniformly distributed, with a non-equilibrium margin less than 0.4% of the averaged chamber pressure. The vapor temperature distribution, however, can be highly non-uniform. The local vapor temperature is influenced by multiple factors, including near-by vapor condensation, heat conduction and convection from vapor movement, and convective heat transfer from cooling pipe and chamber wall. The transient thermocouple measurements can be significantly deviated from that of vapor, due to the thermal capacity of the thermocouple as well as the thermal radiations from cooling pipe and chamber wall. The deviation margin in temperature measurements can be thermocouple-location sensitive.
Analysis of the Non-Linear Dynamic Responses of an Elastic Rotor With a Slant Crack
Authors: Zhang Xiangmin , Chen Changping , Dai Liming
Published: October 2013

Considering a rotor system with a slant crack, and using an equivalent line-spring model to simulate the slant crack of the rotor, the flexibility model of the slant-cracked rotor is derived. Then considered the geometric non-linearity and based on the Lagrange equations, the non-linear dimensionless differential equations of motion for the slant-cracked rotor are obtained. Further the non-linear dynamic responses of the single rotor system with a slant crack are discussed by the Galerkin method and the harmonic balance method. It’s detailedly studied that the angle, the depth and the position of the slant crack on the rotor all affect on the non-linear dynamic responses of the rotor system, and the conclusion is very significant to the design of the rotor system in the practical reference aspect.
Experimental Study of the Influence of Surface Coke Deposition on Heat Transfer of Aviation Kerosene RP-3 at Supercritical Pressure
Authors: Jia Z. X. , Xu G. Q. , Wen J. , Deng H. W.
Published: October 2013

Experiments are performed to study the effect of surface coke deposition on heat transfer of aviation hydrocarbon RP-3 under supercritical pressure. The flowing RP-3 kerosene is stressed to 5MPa, and heated up to 130°C to 450°C in a stainless tube (1.8mm I.D., 2.2mm O.D., 1Cr18Ni9Ti) with a constant heat flux, and the mass flow rate is 3g/s. The working fluids flowed downwards through an 1800mm long tube. The experimental results indicated that insoluble products deposited onto metal surface have a significant impact on flow resistance and heat transfer the effect of coke deposition on heat transfer coefficient can be divided into four regimes: a) onset heat transfer enhancement zone; b) transition zone; c) heat transfer impairment zone; d) heat transfer stabilizing zone.
Performance Emission and Combustion Characteristics of Diesel Engine Fuelled With Biodiesel–Diesel–Diethyl Ether Blends
Authors: Anand R. , Kannan G. R. , Karthikeyan P.
Published: October 2013

Increasing energy demand and rapid depletion of fossil fuels has accelerated the search for an alternative fuel for diesel engine. Biodiesel produced from waste cooking oil is the most suitable alternative for diesel due to low production cost. Higher viscosity, pour and cloud point of biodiesel causes several engine operating problems such as injector choking, piston ring sticking and unfavorable pumping and spray characteristics. In order to avoid the problem associated with biodiesel various combinations of biodiesel-diesel-diethyl ether were prepared in this present investigation. Based on the stability and fuel properties close to diesel the combination namely B70D20DEE10 (biodiesel 70%, diesel 20% and diethyl ether 10%) was further selected for experimental investigation. Experiments were performed on a single cylinder direct injection water cooled diesel engine under varying load, injection timing and injection pressure while keeping engine speed constant of 1500 rpm. The highest brake thermal efficiency was reported for B70D20DEE10 at an injection timing of 25.5 bTDC and injection pressure of 260 bar at full load condition which is 5.6% higher than diesel. The highest heat release rate (HRR) was observed at above operating condition is 29.4 MJ/°CA, which is 5.3% higher than diesel. Further a slight reduction in unburnt hydrocarbon (UBHC) by 12 ppm, nitric oxide by 116 ppm and smoke opacity by 18% was observed when compared to diesel.
Research on Mechatronic Coupling Facts of Linear Motor Feed Drive System Based on Spectrum Characteristics
Authors: Liu Hui , Yang XiaoJun , Zhang Huijie , Zhao Wanhua , Zhang Jun , Cao Kun
Published: October 2013

In this paper, the servo thrust and mechanical structure are analyzed in frequency domain using Maxwell Tensor and Dale Bert’s principle, respectively. Three modes of mechatronic coupling are found as follows. 1) The thrust spectrum varies with velocity, which leading to a worse dynamic precision and even instability when the coupling occurs at a certain resonance frequency between the thrust and the mechanical structure; 2) The coupling occurs between mechanical structure and servo system when adjusting the gain in speed control loop or current control loop. 3) The output of linear encoder will fluctuate due to the variation of normal force between the mover and stator, which leading to the variation of the servo thrust spectrum and a re-coupling between servo drive and mechanical structure. In addition, the mechanism and influence factors of the three types of coupling are studied, respectively. The results show that the spectrums of servo drive system and mechanical structure evolve under different control parameters and operational condition, and happen to interaction once at the same natural frequency. Finally, the associated experiments are performed to verify the previous analysis.
Study on Performance and Emission Characteristics of DI Diesel Engine Fuelled With Deccan Hemp Methyl Ester
Authors: Balasubramanian K. R. , Anand R. , Venkatesh B. , Kannan G. R. , Sivapirakasam S. P.
Published: October 2013

The world needs an alternative fuels that could maintain the world running on its wheels due to the increasing energy demand and uncertainty in availability of the fossil fuels. The present investigation analyzes the scope of utilizing the Deccan hemp oil based biodiesel derived from jute seed as an alternative to the diesel. Experimental investigation was carried out at diesel engine with different loads from 0% to 100% and 10% overload condition under a constant speed of 1500 rpm. It was found that the reduction in brake thermal efficiency and higher brake specific fuel consumption was observed with biodiesel in comparison with diesel. The carbon monoxide (CO), carbon-dioxide (CO2), unburnt hydrocarbon (HC) and nitric oxide (NO) emissions for Deccan hemp oil based biodiesel were reduced by 0.2% vol, 1.6% vol, 62.5%, 36.84% whereas slightly higher smoke emission was observed when compared to diesel fuel. These studies revealed that Deccan hemp oil based biodiesel can be used as a fuel in compression ignition engine without any engine modifications.
Study on Frequency Variety Stiffness of Metal Springs
Authors: Liu L. , Zhang W. H. , Li Y. , Huang G. H.
Published: October 2013

For the sake of studying dynamic characteristics and the response of dynamic stiffness to driving frequency in metal helical spring, the paper studied on rolling stock spring (helical spring). The paper adopted FEM to establish the finite element model of the spring, calculate out steady-state spring’s response and draw frequency-amplitude characteristic curve of the spring. The results indicate that spring dynamic stiffness is increasing with the increase of driving frequency in general tendency, dynamic stiffness is minimal and smaller than static stiffness corresponding to resonant frequencies and, however, dynamic stiffness is maximal and greater than static stiffness corresponding to anti-resonant frequencies. In order to apply the result in simulation, the paper proposed an equivalent algorithm, compared the calculating result of the equivalent model with one of the spring model and found that the gap between them was very small. So remarkable dynamic characteristic exists in metal helical spring and it is doable to make multi-degree of freedom system be equivalent to continuous spring system.
Analytical Modeling and Experimental Measurements of Ternary Molten Salt Heat Transfer Fluids for Energy Applications
Authors: Coscia Kevin , Neti Sudhakar , Oztekin Alparslan , Elliot Tucker , Mohapatra Satish
Published: October 2013

One of the major impediments of current energy applications is the availability of an economical and reliable heat transfer fluid. Such applications include concentrated solar power, gas processing, petrochemicals, nuclear, and other high-temperature processes. Organic heat transfer fluids currently in use have limitations approaching 390°C, and other salt-based fluids have rather high freezing temperatures. Ternary nitrate salts have the potential to operate at high temperatures while maintaining low freezing temperatures. Some melting temperatures of LiNO3-NaNO3-KNO3 salt mixtures as a function of LiNO3 composition have been investigated using differential scanning calorimetry. Phase diagrams have also been predicted for the LiNO3-NaNO3-KNO3, CsNO3-NaNO3-KNO3, and CsNO3-LiNO3-KNO3 systems using mathematical modeling and the results are encouraging. The results presented in this work are expected to make a significant impact on the development of economical and practical ternary nitrate mixtures in energy applications.
Simulation of Biomanipulation Using Molecular Dynamics
Authors: Pishkenari H. Nejat , Mahboobi S. H. , Mahjour M. A. , Meghdari A.
Published: October 2013

In this paper, the simulation of biomolecules manipulation using molecular dynamics (MD) is studied. In order to investigate the manipulation behavior, we have used the ubiquitin as biomolecule, a single-walled carbon nanotube (SWCNT) as manipulation probe, a two-layer graphene sheet as substrate. Along this line, a series of simulations are conducted to study the effects of different conditions on the success of manipulation process. These conditions include tip diameter, vertical gap between the tip and substrate, initial orientation of protein, and the tip position with respect to the biomolecule.
The Slippage Analysis at Bearing Surface of Bolted Joints due to Cyclic Transverse Loads
Authors: Zhu Linbo , Hong Jun , Yang Guoqing , Li Baotong , Yang Zhaohui
Published: October 2013

Bolted joints are widely used in mechanical structures due to their easy installation and maintenance. However, self-loosening of bolted joints caused by cyclic transverse loads has remained unsolved. In this study, the parametric finite element (FE) model is established to simulate the self-loosening. The slippage state at bearing surface and thread surface is investigated based on the FE model. Moreover, the influences of transverse frequency, amplitude, friction coefficient and initial preload on residual preload are discussed under a certain amount of time; the variations in back-off angle of nut and residual preload with time are analyzed under multi transverse loops. The results show that thread surface undergoes complete slip prior to the bearing surface, which provides theoretical guidance for looseness-proof design of bolted joints to some degree. The FE model can also be used to design the initial preload and predict the connections life under given vibration environment.
Aeroelastic Computation of a Wind Turbine Blade Profile
Authors: Nejat A. , Abianaki M. R. , Rahbari I.
Published: October 2013

Wind turbine is one of the important devices to extract clean energy from the wind flow. The efficiency of wind turbines must be examined under various working conditions in order to estimate the off-design performance. Numerous aerodynamic and structural research works have been carried out to compute the aeroelastic effects on wind turbines. Most of those suffer from either simplicity of the modeling approach or from the difficulty of the computing technique which limit the practical applicability of the results. In this research, a robust approach is proposed to compute the aeroelastic behavior of a horizontal axis wind turbine for the preliminary design purposes. The simplicity and applicability of the taken approach are the significant points of the research work. Aerodynamic and elastic computations are done using XFOIL and MATLAB PDE toolbox respectively. Those software are linked through an algorithm to compute aeroelastic effects interactively. A real measured time history of wind velocity is used as an input flow condition to simulate a real of angle of attack for the aeroelastic computation. Investigation of numerical output shows lift and drag coefficient values are lower compared to corresponding values of the rigid profile. Also the study of modulus of elasticity value on the separation point location is conducted and the delayed stall is observed by decreasing the airfoil rigidity.
Developing an Effective Platform for Introducing Mechanical Engineering in a Large Public University
Authors: Lilly Blaine W. , Abrams Lisa M. , Neal Michael , Srinivasan K. , Mendelsohn Daniel
Published: October 2013

In conjunction with a shift from an academic calendar based on ten–week quarters to one based on semesters, the Department of Mechanical and Aerospace Engineering at The Ohio State University has completely re–designed the mechanical engineering curriculum. As a part of this re–design, the MAE department has added a new course for sophomores entering the department that will emphasize hands–on skills in machining and electronics while simultaneously giving students a broad introduction to the kinds of problems that mechanical engineers typically confront in industrial practice.

This paper describes the evolution of our thinking as we created the teaching platform that is the heart of the course, a multi–cylinder compressed air motor. Lectures are structured to provide ‘just in time’ information to the students as they build and test this platform in the laboratory. It was crucial to create a device that would be complex enough to challenge the students and provide an opportunity to explore the widest possible range of mechanical engineering concepts. After a review of similar courses in other programs, we decided to employ a multi–cylinder compressed air motor, controlled by a commercially available microprocessor, as the teaching platform.

Because the course will be required of all students entering the major, an overriding constraint on the design is that the device is simple enough for three hundred students a year, working in teams, to construct and test it. At the same time, the air motors must also be complex enough to support the learning objectives of this course and subsequent courses in the curriculum. Our final design is a direct–injection six–cylinder radial compressed air motor that is controlled by an Arduino© microprocessor. Students will spend five weeks machining and assembling the motors in the machine shop, another four weeks learning to program the Arduino© to control the motor, and the remainder of the term testing and analyzing the performance of the motors.

The air motors allow us to introduce students to machine design, engine design, thermodynamics, fluid flow, vibrations, electronics, and controls. We have pilot tested this course twice, and find that the students quickly take ownership of the motors, and are quite interested in optimizing the design to improve performance.
Leaf Spring Flats, A Frugal Alternative for Making Rotavator Tines
Authors: Bheeman Balaji Visvanath , Badrinarayanan Nivrithi , Mohan Varadharajan , Sivaprakasam Sabarish , Venkataperumal Pramodh
Published: October 2013

A rotavator plays a significant role in tilling soil, which is the primary phase in crop production. Tillage is one of the most energy demanding operations of the agricultural production process. In spite of the rotavator’s versatility, the material used for development of the rotavator tines is found to wear out quickly at very high rates during field work. The blades which cost an average of ₹ 150 in the market wear out after a meagre 60 hours of usage. Considering the Indian agricultural market which has its farmers based in the rural areas, the blades are quite unaffordable. Focusing on a frugal alternative, this work presents a feasible solution of cheap, durable rotavator tines manufactured using discarded leaf spring flats. The study was aimed at analyzing abrasive wear with different samples of tine material, taking into account the soil characteristics as well. Samples of forged leaf spring flats of two different materials (Mn dominant and Si dominant) were taken along with a few commercially available tines from leading brands. The tine samples were split into lots and designated with markings. The profile outlines of all the tine samples were traced. The work then involved analysis and validation by a field test for 25 hours under known soil conditions using a commercial tractor and a rotavator. Upon completion of the field test, the tines were analyzed for wear on a gravimetric and a dimensional basis. The worn-out tine profiles were also traced for comparative visual representation of the wear. It was then concluded that Mn dominant leaf spring flats were more wear resistant and proved to be a prudent substitute for commercially available tine materials.
Numerical Analysis of Convective Heat Transfer of Nanofluids for Laminar Flow in a Circular Tube
Authors: Kirez Oguz , Yazicioglu Almila , Kakac Sadik
Published: October 2013

In this study, a numerical analysis of heat transfer enhancement of Alumina/water nanofluid in a steady-state, single-phase, laminar flow in a circular duct is presented for the case of constant wall heat flux and constant wall temperature boundary conditions. The analysis is performed with a newly suggested model (Corcione) for effective thermal conductivity and viscosity, which show the effects of temperature and nanoparticle diameter. The results for Nusselt number and heat transfer enhancement are presented in graphical and tabular forms, for a given Peclet number, nanoparticle volumetric fraction, and particle diameter in the thermal entrance region. The results are compared with the experimental results available in the literature under the same conditions and a good agreement is found. The two boundary conditions are compared and slightly differing results are discussed. Finally, the effect of the axial conduction and viscous dissipation are investigated. The axial conduction effect is found to be negligible for practical cases while the viscous dissipation effect is found to be significantly important depending on the boundary conditions and the pipe diameter.
Computational and Experimental Investigation of the Low Velocity Impact Behavior of Nano Engineered E-Glass Fiber Reinforced Composite Laminates
Authors: Rasel Abu , Kimbro Evan , Mohan Ram , Kelar Ajit D.
Published: October 2013

This paper presents computational and experimental investigation of the low velocity impact behavior of nano engineered E-glass fiber reinforced composite laminates. The Tetra Ethyl Orthosilicate (TEOS) chemically engineered glass nanofibers were manufactured using electrospinning technique and were investigated for their potential to improve the interlaminar properties. Plain weave fiberglass prepregs were used for manufacturing ten ply thick laminates. For production of the laminates with electrospinning interface layers the addition of the electrospinning sheets and an additional layer of resin film was used. The fabricated laminates were subjected to low velocity impacts of various energy levels to study the progressive damage and deformation mechanics of fiberglass laminates with and without electrospun nanofibers. The low velocity impact behavior was modeled using the transient dynamic finite element program LSDYNA. It was observed that the simulations results are in good agreement with the experimental results for lower impact energies. In addition, the simulated maximum impact force is smaller than the experimental value (soft response) at each drop height and at higher energy levels, the area under impact force vs time increases when electrospun nanofibers are used in the laminates. The study indicates that, the impact duration increases when electrospun nanofibers are used. Impact duration increases due to an additional damage accumulations in electrospun nanofibers layers. Both computational and experimental investigations clearly indicate that inserting interlaminar electrospun nanofiber layers improves the impact resistance of composites by absorbing additional impact energies.