bluuebunny/crossref_metadata_2025 huggingface dataset:
Improvements of Performance and Emissions of a Diesel-Gen-Set With Biodiesel Having Guide Vanes of Various Angles
Authors: Bari S. , Saad Idris
Published: February 2017

Biodiesel has physiochemical properties similar to diesel fuel and it is renewable. It can be used in diesel engines with no or minor modifications. If biodiesel can be produced from renewable sources such as vegetable or other sources, the CO2 emission produced from the engine running on biodiesel can be consumed by the source itself. Then, the net production of CO2 emission in the atmosphere will be zero. However, the viscosity and density of biodiesel are higher than diesel fuel. These inferior properties make biodiesel less prone to evaporate, diffuse and mix with in-cylinder air resulting in inferior combustion and lower engine performance than diesel fuel. If the in-cylinder air-turbulence inside the combustion chamber can be increased, then this will probably enhance the higher viscous and lesser volatile biodiesel to evaporate faster and mix with air better resulting in better performance. Therefore, in this research, guide vanes were installed into the intake runner to increase the in-cylinder air turbulence especially during the injection period. Five guide vanes with the angles of 25°, 30°, 35°, 40° and 45° were fabricated and tested. The vanes were tested on a diesel-gen-set and run with 100% biodiesel. Based on the experimental results, the vane angle of 35° was found to be optimum as this vane angle showed the highest reductions of break specific consumption, CO and HC by 1.77%, 8.78% and 7.5%, respectively compared to the run with biodiesel without vanes. The other vanes showed lower improvements. Therefore, this research concludes that the improvement of in-cylinder air-turbulence can enhance the engine performance with higher viscous biodiesel.
High-Precision Tracking Control of Machine Tool Feed Drives Based on ADRC
Authors: Zhang Chengyong , Chen Yaolong
Published: February 2017

In this paper, the active-disturbance-rejection control (ADRC) is applied to realize the high-precision tracking control of CNC machine tool feed drives. First, according to the number of the feedback channel, the feed systems are divided into two types: signal-feedback system, e.g., linear motor and rotary table, and double-feedback system, e.g., ball screw feed drive with a load/table position feedback. Then, the appropriate controller is designed to ensure the closed-loop control performance of each type of system based on the idea of ADRC. In these control frameworks, the extended state observers (ESO) estimate and compensate for unmodeled dynamics, parameter perturbations, variable cutting load, and other uncertainties. For the signal-feedback system, the modified ADRC with an acceleration feedforward term is used directly to regulate the load/table position response. However, for the double-feedback system, the ADRC is applied only to the motor position control, and a simple PI controller is used to achieve the accurate position control of the load. In addition, based on ADRC feedback linearization, a novel equivalent-error-model based feedforward controller is designed to further improve the command following performance of the double-feedback system. The experimental results demonstrate that the proposed controllers of both systems have better tracking performance and robustness against the external disturbance compared with the conventional P-PI controller.
Parametric Study of the Effect of Particles and Contaminants on the Static Response of a MEMS System
Authors: Vutla Srinivasa Rao , Regalla Srinivasa Prakash , Ramaswamy Kannan , Pattnaik Prasant Kumar , Mandalika Bala Srinivas
Published: February 2017

This paper reports the effect of particulate contaminants on the static stress response of cantilever type micro-electromechanical systems (MEMS) devices, such as high precision MEMS pressure sensor. The contaminant presence has been qualitatively verified through computational fluid dynamic simulation of the clean room in COMSOL Multiphysics environment and quantitatively estimated for adverse conditions such as ISO-8 cleanliness. There is very little characterization of such impairing of response of cantilever systems though it has well been recognized to be important. Fabrication of MEMS based multi-functional devices demands complex integration of several micro-engineered components to perfection. It is therefore critical to ensure that at every stage of fabrication the contaminants or particles that get deposited on the device parts do not have any deleterious effect on the device performance. As most of the MEMS based devices are fabricated in a clean room environment the effects of contaminants on the device performance is assumed to be minimal. However, if the components are exposed to adverse conditions of cleanliness due to non-functional cleanroom or poor maintenance of cleanroom, the unaccounted mass of contaminants on the cantilever device can affect the static and dynamics response as well as the resonance characteristics. Thus it is important to understand performance with respect to various clean room parameters such as particulate density, temperature and humidity especially for the devices designed to measure very low values of physical/electrical/mechanical parameters.
Probabilistic Description of the Function-Structure Relationship in Products
Authors: Wang Pan , Li Yuan , Zhang Jie , Yu Jianfeng
Published: February 2017

Providing the designers with the relationship between functions and structures is an effective way to accelerate the design process. Currently, the function-structure relationship is usually obtained by theoretically analyzing the transformation from function to structure, such as the FBS model. Though these methods have provided the reasonable explorations of the function-structure relationship, they are complicated and not easy to achieve. Since the function-structure relationship in the existing products also follows the design pattern described by the existing studies, extracting the function-structure relationship from these products instead of the theoretical analysis could also transfer the significant information that what structures could satisfy the required function. Therefore, this paper presents an estimation approach to obtain the probabilistic description of the function-structure relationship in products. First, the product, structure and the functions contained by a product are described with product vector, structure vector and function vector, respectively. Meanwhile, the relationship between them is also defined. Then, a statistical strategy is proposed that treats all the products as the population and the products we gather as the sample, and defines the function-structure relationship as the conditional probability of the appearance of a structure given a function in the gathered products. Afterwards, the maximum likelihood estimation (MLE) is employed to estimate the conditional probability. Compared with other methods, the proposed approach replaces the theoretical analysis with discovering the products, which avoids the complicated modeling and description of the function-structure relationship. In case study, some experiments have been carried out, and a plug-in tool is developed to implement the application of the extracted function-structure relationship in product design. The results have shown the feasibility of the proposed approach and demonstrated the practical value in engineering.
Synthetic and Organic Supercharger Lubrication: The Tribological Performance of Ionic Liquids as Additives to Lubricants
Authors: Bain Derek , Fisk Dana , Gomez Serrano Camila , Orlando Samantha , Iglesias Patricia
Published: February 2017

A supercharger is a mechanical device that can be added to an engine of a car to increase engine power. It works by sucking air in at atmospheric pressure into the rotors and compressing it at high revolutions per minute. With the rotors spinning at high speeds, the supercharger gears are exposed to high values of friction and wear, which results in a reduction of their service life.

Ionic liquids (ILs) are substances that possess unique lubricating abilities when added to base oil or when used as neat lubricants. Properties include low volatility, non-flammability, as well high thermal resistance. These liquids are able to form ordered layers and tribofilms on the contacting surfaces which further protects the surface materials. In this work, the effect of adding ILs to low viscosity synthetic oil used to lubricate gears and to organic oil was investigated in the reduction of friction and overall wear of superchargers. Mobil 1 5W-30 Full Synthetic Engine Oil (MS) was used as a control and compared to coffee bean oil (CB). Additionally, the performance of these oils was observed with ionic liquids as additives at 1 wt. %. The chosen IL consisted of the cation Trihexyltetradecylphosphonium, [P6,6,6,14]+, with the anion Bis(trifluoromethylsulfonyl) amide, [NTf2]−. Lubricated flat disks of AISI 52100 stainless steel and 420C steel balls were studied using a Pin-on-Disk configuration. A total sliding distance of 500 meters was tested with a wear track diameter of 20 mm. Wear volume and average friction coefficient were measured according to ASTM-G99. Results showed that the addition of the ILs to the CB and MS reduced friction coefficient of the steel disks at medium speeds, and wear values achieved were comparable to the friction observed. The wear width values were also found to be reduced at medium speeds.
A Study of Shape Optimization Method on Connection Cones for Diesel Particulate Filter (DPF)
Authors: Mu Mingfei , Li Xinghu , Aslam Jawad , Qiu Yong , Yang Hao , Kou Guiyue , Wang Yan
Published: February 2017

For diesel vehicles equipped with a Diesel Particulate Filter (DPF), flow resistance (pressure drop) is a vital factor affecting power performance, fuel consumption and regeneration performance. Traditional methods for DPF pressure drop reduction mainly focus on developing a new filter material, optimizing its microstructure and structural parameters of gas channels. Although the above methods have greatly reduced the pressure drop, it is still difficult to meet the demand of increasingly stringent energy consumption and carbon emissions standards. Thus, improving the shape of connection (inlet and outlet) cones to further reduce pressure drop has become one of the important topics of DPF development.

In this paper, a simulation model of gas-particle two-phase flow through traditional connection cones has been established and wall-flow filter element is modeled with an equivalent porous material. The flow through DPF has been simulated with Fluent computational fluid dynamics (CFD) software under different exhaust emission velocities, expansion angles and ratios. The influence factors for flow uniformity and pressure drop in DPF have been analyzed. The variation tendency of pressure drop, flow velocity, vorticity, and turbulent kinetic energy in connection cones has been obtained. And then, based on calculation results and Non-Uniform Rational B-Splines (NURBS) theory, the fitting cure of optimum connection cones are drawn out at different expansion angles and ratios, compared with the calculation results of traditional connection cones, to deduce advantages of optimum connection cones on the flow uniformity and pressure drop.
Assessing the Target Reliability Index for Nuclear Piping
Authors: Avrithi Kleio
Published: February 2017

Previous research developed Load and Resistance Factor Design (LRFD) equations for Class 2 and 3 nuclear piping for different reliability levels and load combinations. The LRFD equations consider separate safety factors for each load and for the strength of steel in opposition to the Allowable Stress Design (ASD) equations used in the ASME Boiler and Pressure Vessel (B&PV) Code, Section III, Div. 1, where only one safety factor is considered. In order to use the developed LRFD equations for the design of nuclear piping, specific reliability levels or else acceptable probabilities of failure need to be assigned to each Code equation. The paper discusses the available methods for evaluating the target reliability index, such as historical data of piping failures, expert-opinion elicitation, and Code calibration. Code calibration is the method of determining the existing level of reliability in the Code equations and assigning the same reliability to the developed LRFD equations in a consistent manner. Code Calibration is explained to be the more appropriate method of assigning reliability levels to the LRFD equations. The other methods can supplement the analysis results.
Divergence Prediction for Practical Helicopter Slung Loads
Authors: Motahari Nicholas , Kim Thomas , Shukla Dhwanil , Hiremath Nandeesh , Komerath Narayanan
Published: February 2017

Certifying the highest safe speed for an aircraft with a slung load, is life-critical yet daunting. Two flight cases are considered, to test an iterative procedure that predicts the divergence speed from experimental scale model data and simulations. The first is an empty engine canister. The second is a segment of a water-floatable military Ribbon Bridge. In each case, mass, geometry, tether length from a single rotation-bearing attachment, and moments of inertia, come from flight preparations. An initial aerodynamic load map is interpolated and synthesized from a growing library on bluff body aerodynamics. Dynamic simulation with these data predict maximum roll, pitch and yaw angles reached as functions of freestream speed. This yieldw a good initial estimate of critical speeds and dynamics. Model-scale wind tunnel data using our Continuous Rotation method about the required axes, refine simulation. For the engine canister, simulations matched detailed flight test data on maximum trailing and rolling amplitudes over the operational speed range. Trail angle data showed that Reynolds number errors are not significant. In this paper, model-based results explained the correct speed where the ribbobn bridge flight test was stopped. While flight test oscillation amplitude histories depend on initial perturbations of the load, a 15-degree initial amplitude gives conservative results. Ribbon bridge airloads resemble those on a long container but with asymmetries. Dynamic behavior follows the general pattern of an intermediate hump in roll amplitude followed by stable operation at higher speeds until divergence occurs.
Numerical and Analytical Investigation of Viscous Fluids in a Screw Extruder
Authors: Ozsipahi Mustafa , Cadirci Sertac , Gunes Hasan
Published: February 2017

This study presents a flow model for a single screw extruder which has been investigated by means of analytical and numerical methods. Flow phenomena in single screw extruders has evoked attention of many researchers since non-Newtonian type of fluid transport by an extruder is utilized in many industrial applications. In this study we focused on the Newtonian-type of fluid transport by a single screw extruder since we aimed to generate an analytical model for the simplified Navier-Stokes equations under certain boundary conditions. The analytical model for a steady, laminar, isothermal and incompressible flow is derived using integral transform technique for a highly viscous flow where the convective acceleration terms are assumed to be negligible. Numerical investigation is conducted by an incompressible, laminar, finite volume based flow solver using a Volume of Fluid (VoF) approximation. An appropriate single-screw extruder model is used for the simulations. The novelty of the study relies on the usage of a simplified analytical model for a highly viscous flow and the comparison between the analytical and numerical results where the numerical results are obtained by a two-phase flow solver for the full Navier-Stokes equations using the complex extruder geometry.
Numerical Comparison and Sizing of Sensible and Latent Thermal Energy Storage for Compressed Air Energy Storage Systems
Authors: Kaya Mine , Tari Ilker , Baker Derek K.
Published: February 2017

Compressed Air Energy Storage is a promising large-scale storage system in part because of its high power rating during discharge. But it is not the cleanest way of storing energy due to the necessity of an external heat source (typically the combustion of natural gas) to heat the air at the turbine inlet. This problem can be overcome with Thermal Energy Storage by storing the thermal energy of air at the compressor exhaust in order to be used for heating air before turbine. In this study, a numerical transient heat transfer model of Thermal Energy Storage is developed and the performance of Thermal Energy Storage is investigated based on heat storage capacity, required time to store unit amount of energy and air temperature profiles at the outlet of Thermal Energy Storage during discharge for the system. High heat storage per volume is necessary for more compact systems. Required time to store unit amount of energy is desired to be short for a fixed volume Thermal Energy Storage in order to maintain continuous operation; on the other hand, air at the outlet (turbine inlet) should be at a high temperature for the longest time possible to supply hot air to turbine. In order to investigate the effects of operating parameters, different volumes of Thermal Energy Storage tank filled with different storage mediums of various sizes are explored. Latent Heat and Sensible Heat Thermal Energy Storage systems are compared using magnesium chloride hexahydrate, paraffin, myristic acid and naphthalene as phase change materials and rock as sensible storage medium. Results show that Latent Heat Thermal Energy Storage gives a better performance than Sensible Heat Thermal Energy Storage. Among phase change materials, magnesium chloride hexahydrate provides the highest heat storage per volume. Required time to store unit amount of energy are comparable among the phase change materials. Magnesium chloride hexahydrate seems promising considering the discharge temperature profile at the Thermal Energy Storage outlet. Capsule size should be kept as small as possible which can be challenging in terms of manufacturing.
Macro-Micro Biomechanics Finite Element Modeling of Brain Injury Under Concussive Loadings
Authors: Tan X. Gary , Przekwas Andrzej J. , Gupta Raj K.
Published: February 2017

Traumatic brain injury (TBI) occurs in many blunt, ballistic and blast impact events. During trauma axons in the white matter are especially vulnerable to injury due to the rapid mechanical loading of brain. The axonal pathology leads to cytoskeletal failure and disconnection. The microtubules are one of major structural components of the cytoskeleton filamentous network. By bridging the macroscopic forces acting on the whole brain with the cellular and subcellular failure, the macro-micro computational models in both time and space can help us better understand the complex biophysics and elucidate the injury mechanism of both severe and mild TBI (concussion). At the macroscopic scale we developed the high-fidelity anatomical human body finite element model (FEM) to predict intracranial pressures and strain and strain rate fields of brain in the blast event. The macro-scale models and the coupled blast and biomechanics approach were validated against test data of shock wave interacting with a surrogate head in the shock tube. The mechanical deformation of brain tissue was mapped to the white matter tracts to obtain local axonal strain and strain rate for the micromechanical models. We developed the micromechanical FEM of myelinated axons interconnected with the oligodendrocyte by the processes, utilizing a novel beam element free of rotational degrees of freedom (DOFs). The numerical results reveal the possible mechanism of impact-induced axon injury including demyelination, breakup of processes, and axonal varicosity. We also investigate the dynamic response of microtubules bundles under traumatic loading. Different from the commonly discrete bead-spring models, a network of microtubules cross-linked with microtubule-associated-protein (MAP) tau proteins was modeled by the nonlinear beam model. Tau protein is modeled by the rate-dependent bar element for its complicated material behavior. The model considers the rupture of microtubule and the failure of tau-tau interface and tau-microtubule interface. The simulation result of the combined effects of the failure of the cross-linked architecture and elongation and bending of the bundle are possibly correlated to the axonal undulations following traumatic loading observed in the experiments. The developed macro-micro biomechanics models can be used as a starting point for modeling the neurobiology effects and guide the design of novel injury protection strategies.
Flow Distribution Control Between Two Parallel Meso-Scale Evaporators With Electrohydrodynamic Conduction Pumping
Authors: Yang Lei , Talmor Michal , Seyed-Yagoobi Jamal
Published: February 2017

Electrohydrodynamic (EHD) conduction pumps generate pressure to drive dielectric liquids via the electrical Coulomb force exerted within heterocharge layers of finite thickness in the vicinity of the electrodes. By applying an external electric field in a dielectric liquid, the heterocharge layers form due to the net charges as a result of the process of enhanced dissociation of neutral molecules versus the recombination of the generated ions. EHD conduction pumping can be applied to enhance and control mass and heat transfer of both isothermal and nonisothermal liquid and two-phase fluid, with many advantages such as simple design, no moving parts and low power consumption. It also shows its potential as an active control technique for flow distribution for multi-scale systems in both terrestrial and microgravity environment. Flow distribution control based on EHD conduction pumping mechanism was previously investigated in macro-scale. This study experimentally examines its capability in controlling two-phase flow distribution between two parallel meso-scale evaporators. The working fluid was refrigerant HCFC-123. It has been found that an EHD conduction pump could effectively control the two-phase flow distribution via adjusting the flow rate in each branch line, and facilitate the recovery from dry-out condition in two-phase system.
Thermal Performance of Asymmetrical Saw-Toothed Microchannels With Phase Change
Authors: Gao Le , Pool James M. , Bhavnani Sushil H.
Published: February 2017

Modern-day microprocessors consist of over one billion integrated circuits on silicon chips as small as a human fingernail. Normal operation of this circuitry produces an enormous amount of heat on a very small footprint. Dissipating this heat is a very challenging task, perhaps the largest roadblock to continued increases in computing technology. Microchannel heat sinks utilizing either single-phase flow or phase-change are an effective means of cooling stacked 3-D microelectronics. A roadblock to practical implementation of microchannels is the presence of flow instabilities. The asymmetric saw-toothed microchannel heat sink is proposed to address this issue. Deep reactive-ion etching is used to produce channels comprised of asymmetric sawtoothed structures that alter the local flow structure within the microchannel. All experiments are conducted using the dielectric fluid, FC-72. Each microchannel array has a footprint of 1 cm × 1 cm, comprised of thirty-four channels etched into a silicon wafer. A series of thin film serpentine copper heaters is fabricated on the other side of the silicon wafer to provide a uniform heat flux boundary condition. Experimental information is presented for a range of mass fluxes from 381 to 1777 kg/m2s, and inlet subcooling from 5°C to 20°C. Parameters presented and analyzed includes boiling curves, onset of boiling (ONB), averaged two-phase heat transfer coefficient.
Identification of Shear Properties for Woven Fiber Reinforced Polymer Simulation
Authors: Yang Dongyang , Stalin Benoit , Xia Yong , Zhou Qing
Published: February 2017

Finite element simulation of composite materials is still challenging as anisotropy of the material brings difficulty in accurately identifying shear properties for modeling. In this study, ±45° tensile tests, Iosipescu shear tests, rail shear tests and Arcan shear tests are conducted to obtain the engineering shear stress-strain curve of woven fiber reinforced polymer. Digital image correlation method is adopted to obtain the strain field of the specimens. It is indicated that Iosipescu shear tests introduce a strain field close to pure shear state while the other three test types introduce relatively large tensile strain or compressive strain. Shear properties obtained from Iosipescu tests are used to calibrate an extensively used composite material model, Matzenmiller-Lubliner-Taylor (MLT) model. The calibrated MLT model is then verified by simulating Arcan tests with different loading angles. The simulations indicate that MLT model gives reliable predictions on Arcan tests with smaller loading angles, while it overestimates the force-displacement responses at larger loading angles.
Energy Optimization of Air Handling Unit Using CO2 Data and Coil Performance
Authors: Razban Ali , Edalatnoor Arash , Goodman David , Chen Jie
Published: February 2017

Air handling unit systems (AHU) are the series of mechanical systems that regulate and circulate the air through the ducts inside the buildings. In a commercial setting, air handling units accounted for more than 50% of the total energy cost of the building in 2013. To make the system more energy efficient without compromising comfort, it is very important for building energy management personnel to have tools to monitor the system performance and optimize its operation. Models are needed to meet the needs. The objectives of this study were to (1) develop models for the AHU elements and (2) implement control strategies to improve energy efficiency without sacrificing room comfort based on the published American Society of Heating Refrigeration and Air Conditioning Engineers (ASHRAE) standard.

In this study, algorithms were developed to model the energy usage for heating/cooling coils as well as fans for AHU. Enthalpy based effectiveness and Dry Wet coil methods were identified and compared for accuracy of evaluating the system performance. Two different types of control systems were modeled and the results were shown based on occupancy reflected by the collected the rooms’ CO2 data. Discrete On/Off and fuzzy logic controller techniques were simulated using Simulink Matlab software and compared based on energy reduction and system performance.

The models were used on an AHU in one of the campus buildings. The data for model inputs were collected wirelessly from the building using fully function devices (FFD) and a pan coordinator to send/receive the data. Current building management system Metasys software was also used to get additional data. The AHU modeling was done using Engineering Equation Solver (EES) Software for the coils and subsystems. Moving Average technique was utilized to process the data.

The models were validated by comparing the calculated results with these measured experimentally. Simulation results showed that in humid regions, where there is more than 45% of relative humidity, the dry wet coil method is the effective way to provide more accurate details of the heat transfer and energy usage of the AHU comparing to the enthalpy based effectiveness.

Also results of fuzzy logic controller method show that 62% of the current return fan energy can be reduced weekly using this method without sacrificing the occupant comfort level comparing to the ON/OFF method. Energy consumption can be optimized inside the building using fuzzy logic controller. At the same time system performance can be increased by taking the appropriate steps to prevent the loss of static pressure in the ducts.

The implementation of the method developed in this study will improve the energy efficiency of the AHU while the occupants comfort level stay intact.
Interconversion of Frequency Domain Complex Modulus to Time Domain Modulus and Compliance of Asphalt Concrete: Numerical Modeling and Laboratory Validation
Authors: Rahman A. S. M. Asifur , Tarefder Rafiqul A.
Published: February 2017

Viscoelastic material functions such as time domain functions, such as, relaxation modulus and creep compliance, or frequency domain function, such as, complex modulus can be used to characterize the linear viscoelastic behavior of asphalt concrete in modeling and analysis of pavement structure. Among these, the complex modulus has been adopted in the recent pavement Mechanistic-Empirical (M-E) design software AASHTOWare-ME. However, for advanced analysis of pavement, such as, use of finite element method requires that the complex modulus function to be converted into relaxation modulus or creep compliance functions. There are a number of exact or approximate methods available in the literature to convert complex modulus function to relaxation modulus or creep compliance functions. All these methods (i.e. exact or approximate methods) are applicable for any linear viscoelastic material up to a certain level of accuracy. However, the applicability and accuracy of these interconversion methods for asphalt concrete material were not studied very much in the past and thus question arises if these methods are even applicable in case of asphalt concrete, and if so, what is the precision level of the interconversion method being used. Therefore, to investigate these facts, this study undertaken an effort to validate a numerical interconversion technique by conducting representative laboratory tests. Cylindrical specimens of asphalt concrete were prepared in the laboratory for conducting complex modulus, relaxation modulus, and creep compliance tests at different test temperatures and loading rates. The time-temperature superposition principle was applied to develop broadband linear viscoelastic material functions. A numerical interconversion technique was used to convert complex modulus function to relaxation modulus and creep compliance functions, and hence, the converted relaxation modulus and creep compliance are compared to the laboratory tested relaxation modulus and creep compliance functions. The comparison showed good agreement with the laboratory test data. Toward the end, a statistical evaluation was conducted to determine if the interconverted material functions are similar to the laboratory tested material functions.
Collision Avoidance Algorithm for a Heavy Commercial Road Vehicle Under Heterogeneous Traffic
Authors: Rajaram Vignesh , Subramanian Shankar C.
Published: February 2017

In this paper, a collision avoidance algorithm (CAA) has been proposed using variable time headway considering heterogeneous traffic. The time headway used in the proposed CAA was tuned based on the traffic scenarios, the host vehicle’s load conditions and the type of the lead vehicle that the host vehicle encounters in the traffic. The proposed variable time headway would help to avoid the intervention of the collision avoidance system during normal driving and gain driver’s acceptance. The CAA was evaluated using a hardware-in-the-loop (HiL) experimental set-up integrated with the vehicle dynamic simulation software IPG/TruckMaker® for different categories of lead vehicles such as 2/3 wheelers, passenger cars, light commercial road vehicles (LCVs) and heavy commercial road vehicles (HCVs). From the results, it was observed that while following a HCV, a smaller time headway was sufficient to prevent a collision compared to following a passenger car, LCV and 2/3 wheeler.
Screw Rotor Profiles of Variable Lead Vacuum and Multiphase Machines and Their Calculation Models
Authors: Stosic Nikola , Rane Sham , Kovacevic Ahmed , Smith Ian K.
Published: February 2017

Twin screw machines are mechanically simple and reliable, having only two moving parts, while their manufacturing cost is low and, as a result of optimization of their rotor proportions and profiles, their efficiency is high. Consequently, they are now used widely both as multiphase and vacuum pumps.

This study gives the results of an investigation of how their performance is affected by changing the rotor lead, i.e. the axial step along the rotor wrap, from a constant value to a variable one. A number of different configurations have been considered and it is shown that, for machines with a large wrap angle, a variable lead results in greater displacement and improved efficiency.
Large Deformation Strain Measurement Using Digital Image Correlation Technique During Axial Crushing of an Extruded AA-6063 Tube
Authors: Sudalaiyandi Arun Kumar , Krishnamurthi Ramesh , Prakash Raghu V.
Published: February 2017

Thin-walled metal tubes are extensively used in aircraft and automobile industries as energy absorbers during collision. When a thin wall tube is subjected to an axial compressive load, lobes are formed sequentially and each lobe undergoes a large plastic deformation without any cracking; this is referred to as progressive buckling. The focus of this paper is to study the displacement and strain fields near the buckled zone of a thin-walled square tube both experimentally and numerically. Quasi-static test was conducted on thin-walled square tubes made of aluminum alloy AA-6063 and the displacement and full-field strain was measured using Digital Image Correlation (DIC) technique. It is noted that while one face of the tube undergoes tensile deformation, the adjacent faces undergo compressive deformation. The strain levels exceed the fracture strain obtained during a tensile test. Strain estimated from DIC was found to be in good agreement with the strain gauge measurements at far field. Further, strain estimations obtained through numerical simulations showed a reasonable agreement with DIC measurements.
Analyzing Fluid Elastic Instability of Vibrating Tubes Failure at HRSG Steam Generator by Adopting Criteria of ASME Sec III Div.1 App. N-1330
Authors: Al-Nasser Adel M.
Published: February 2017

Current study analyzes dynamic instability of evaporator tube array at heat recovery steam-generator (HRSG) that encounters repetitive tube vibration failure. The tube array experiences turbulent swirling flue-gas. The analysis according to ASME criteria predicts critical instability velocities at 26.2 m/s, dimensionless reduced velocity factor at 85.7 and dimensionless mass damping at 50.2. These levels create large response of high vibration amplitude of tube reflecting strong coupling between tube structure and exhaust gas. CFD model for exhaust gas flow regime upstream tube array predicts large variation in velocity. The model is not validated but results agree with experience of repetitive tube failure within the high velocity profile sections. The calculated natural frequency of tube is 6 Hz, dimensionless reduced mass damping factor of tube is found at 243 meeting ASME criterion of greater than 64. Thus, synchronous vortex shedding vibration will not occur at the tube. Last, HRSG encounters structural vibration, cracks and high noise level at stack side. Fundamental acoustic frequency and vortex shedding frequency are calculated at 65 Hz and 134 Hz, respectively. These values don’t meet 80–120% range. Thus acoustic vibration noise will not occur.
Engineering Options for an Emission-Free Global Economy by 2050
Authors: Platzer Max F. , Sarigul-Klijn Nesrin
Published: February 2017

An overview is presented of the two engineering options which have been offered during the past seven years to accomplish a complete transition to renewable global power generation by 2050. These two approaches are the Wind-Water-Solar program, proposed by Jacobson and Delucchi, and the Energy Ship program, proposed by Platzer and Sarigul-Klijn. A comparative evaluation of the technical, economic and social acceptability aspects of the two options is given. It is argued that the demonstration of techno-economic feasibility needs to be supplemented by an additional ranking criterion, namely the social acceptability factor, in order to select the most promising engineering approach for a successful transition to an emission-free global economy by 2050.
Review of Solar Sorption Cooling Research in the MENA Region
Authors: Mohammad Iqbal Abdul Ahad , Al-Alili Ali
Published: February 2017

This paper provides a brief overview of closed sorption cooling technologies, and highlights the research performed on them in the Middle East and North Africa region. The main findings are summarized and presented in tabulated and graphical forms. The reviewed studies are compared in terms of the working pair, the Coefficient of Performance, the normalized collector area, etc. The results show that the average cyclic Coefficient of Performance for the adsorption chillers was 0.41, whereas the average chiller Coefficient of Performance for the absorption chillers was 0.677.

The research trends reveal that interest in solar sorption cooling was low in the 1980s and 1990s, and gradually increased during the 2000s. In addition, the most installed solar cooling system in the Middle East and North Africa region is utilizing absorption cycles.
Analysis of Total Head Loss in Various Configurations of Spiral Casing: A Numerical Study
Authors: Nakkina Parameswara Rao , Karaiyan Arul Prakash , Gurunathan Saravana Kumar
Published: February 2017

Numerical simulation of fluid flow through various configurations like decelerated, free vortex, accelerated and spiral casing with different aspect ratios (AR) based on cross section has been studied using finite element method. An explicit Eulerian velocity correction scheme has been deployed to solve the Reynolds averaged Navier-stokes equations. The simulations have been performed to describe the fluid flow in high Reynolds number (106) regime. A streamline upwind Petrov Galerkin technique has been used for discretising governing equations. The pressure distribution inside the spiral casing has been studied. Total head loss for all configurations with various aspect ratios is modeled using response surface approximation. Subsequently, unconstrained non-linear minimization method is implemented to obtain optimum spiral casing by minimizing the total head loss.
Electromagnets as Actuators for a Novel 3D-Printed Musculoskeletal Prosthesis
Authors: Hamade R. F. , Assaad Magdalena , El Hajj Diana , El Jurdi Julie
Published: February 2017

3D printing was used to produce custom and anatomically-faithful prototype prosthesis device as a missing hand replacement. 3D-printed bones (ABS) were actuated electromagnetically activated copper wire coils (resulting in field of about 9 mT) via nylon lines being attached to one side of the metacarpal bones of the hand, one for each finger, and the other attached to the distal phalanges providing sufficient force for finger bending and functioning. For emotional factors, the device was wrapped in an exact replica of the amputee’s hand anatomy obtained by mirror-imaging the other existing hand.
Computational Analysis of the Methane Steam Reforming Process With Low-Temperature Waste Heat Source
Authors: Shin Gahui , Yun Jinwon , Yu Sangseok
Published: February 2017

When the high temperature stationary fuel cell system is designed with external reformer, typical approach to improve efficiency of system is to employ catalytic burner with fuel lean anode-off gas for methane steam reformer. Recently, there have been many studies on the hybrid fuel cell system using anode-off gas to produce additional power. In those hybrid systems, maximum temperature of heat duty for the reformer is significantly reduced. Optimization of heat management is very important for these low temperature reformers. In this study, we carried out an analytic study of the methane steam reforming process with heat duty of non-reactive, low temperature gases. It is found out that the temperature uniformity of inlet gases is crucial for high efficiency. Additionally, the reformer geometry such as heat transfer area and the aspect ratio are meaningful parameters which can severely affect the methane conversion rate under given conditions.
Closed-Loop Subspace Identification of MIMO Motion System With Flexible Structures for Motion Control
Authors: Huang Tao , Yang Kaiming , Cheng Rong , Mu Haihua , Zhu Yu
Published: February 2017

In this paper, we study the closed-loop subspace identification of MIMO motion system with flexible structures. The fundamental objective of identification experiment is to achieve the state space model for motion control. The model with flexible structures of the motion system is analyzed and deduced to the form of state space model, which is composed with rigid modes and flexible modes. As the stability and safety case, the closed-loop subspace identification method is employed. The proposed identification method is suitable for modern control algorithms to construct space state model. The rigid and flexible modes are obtained and updated by the modal approach. Identification experiment is carried on the industrial wafer stage, which is the typical MIMO motion system with flexible structures. The results of experiment verify the feasibility and validity of the proposed identification method.
Enhanced Heat Transfer and Thermal Performance of Metal Foam Microchannel Heat Sinks With Internal Y-Shaped Bifurcation
Authors: Shen Han , Liu Xueting , Sunden Bengt , Xie Gongnan
Published: February 2017

Internal Y-shaped bifurcation has been proved to be an advantageous way on improving thermal performance of microchannel heat sinks according to the previous research. Metal foams are known due to their predominate performance such as low-density, large surface area and high thermal conductivity. In this paper, different parameters of metal foams in Y-shaped bifurcation microchannel heat sinks are designed and investigated numerically. The effects of Reynolds number, porosity of metal foam, and the pore density (PPI) of the metal foam on the microchannel heat sinks are analyzed in detail. It is found that the internal Y-shaped bifurcation microchannel heat sinks with metal foam exhibit better heat transfer enhancement and overall thermal performance. This research provides broad application prospects for heat sinks with metal foam in the thermal management of high power density electronic devices.
Development of Surface Treatment Technique With Photolytic Macromolecule Including RGDS Peptide
Authors: Taki Y. , Morita Y. , Nishimura S. , Hirata A. , Koga T. , Nakamachi E.
Published: February 2017

Arg-Gly-Asp-Ser (RGDS) coating is one of effective methods to improve the cell adhesive property of the scaffold surface. However, it is difficult to regulate the RGDS quantity and distribution, and to visualize RGDS distribution. The purpose of this study was to develop a surface treatment technique that the RGDS quantity can be regulated with the ultraviolet rays irradiation and the RGDS distribution can be visualized with the fluorescence. P(MMA-g-ANP-RGDS) and P(HEMA-g-ANP-RGDS) were respectively synthesized by radical copolymerization of methylmethacrylate (MMA) and 2-hydroxyethylmethacrylate (HEMA) with peptide-macromonomer containing photo-labile linker (3-amino-3-(2-nitrophenyl)propionic acid (ANP)) and RGDS. Each polymer film was produced by using spin-coater, and then ultraviolet rays was irradiated to the each film through the glass mask with three different ultraviolet rays transmissivity of 0 %, 30 % and 60 %. In both polymer films, the RGDS quantity can be regulated by ultraviolet rays irradiation, and the luminance decreased same as the RGDS quantity. Adherent osteoblast-like cells were not observed on P(HEMA-g-ANP-RGDS) film, but the number of adherent osteoblast-like cells was increased with increasing the RGDS quantity on the P(MMA-g-ANP-RGDS) film. In conclusion, we accomplished to develop the surface treatment technique with P(MMA-g-ANP-RGDS) to regulate and visualize the RGDS quantity and distribution.
Rheological Characterization of Green Sand Flow
Authors: Jabbari Masoud , Spangenberg Jon , Hovad Emil , Comminal Raphaël , Hattel Jesper H. , Hartmann Katja I. , Schütz Denis
Published: February 2017

The main aim of this paper is to characterize experimentally the flow behaviour of the green sand that is used for casting of sand moulds. After the sand casting process is performed, the sand moulds are used for metal castings. The rheological properties of the green sand is important to quantify as they can be used to evaluate whether the casting process will be successful. In addition, the properties can potentially be implemented in a computational fluid dynamics model which can be used as a tool to optimize the process. The rheological experiments are carried out on a MCR 502 rheometer with a new module for characterizing granular materials. The new module enables viscosity measurements of the green sand as function of the shear rate at different flow rates, i.e. 0, 2, 4, 6, 8, 10, 12 and 15 L/min. The results show generally that the viscosity decreases with both the shear- and flow rate. In addition, the measurements show that the green sand flow follows a shear-thinning behaviour even after the full fluidization point.
Damage Quantification and Location Detection in Carbon Nanotube Enhanced Composite Panels
Authors: Ardebili Mahmoud K. , Ikikardaslar Kerim T. , Sugrim Shivron , Delale Feridun
Published: February 2017

Epoxy resin based composite panels enhanced with carbon nanotube were subjected to damage while their electrical resistivity was monitored. The objective of the study was to utilize the composite piezoresistivity as means of damage quantification and location detection. Two different multi walled CNT-epoxy composites were manufactured for this study: one was CNT enhanced epoxy resin and the second was glass fabric reinforced CNT epoxy resin. Rectangular panels of various proportions were studied. Disks made out of copper foil were affixed to surfaces of CNT epoxy specimen, while in glass fabric CNT epoxy specimen the disks were embedded inside the samples. The disks acted as electrodes, enabling resistivity measurements using Kelvin in-line four-probe technique. The technique minimizes contact resistance between electrodes and the composite. Two different configurations of electrode network were employed to scan resistivity of entire samples. The networks included evenly spaced electrodes that spanned the entire surface of the panel, and one that covered the panel’s diagonals and its edges. To further investigate influence of electrodes distribution, finite element methods were employed to solve for the electrical potential distribution in the panel simulating various damage location and extent. Pre and post damage resistivity change was used as gauge in determining the damage location and its extent quantification. The finite element method simulation results matched experimental data closely allowing further studies with electrodes distribution, damage geometry and location. The results indicated that a relatively small spaced electrode network is capable of determining location and quantification of visible and hardly visible damages. As spacing between electrodes is increased they become less responsive to smaller damages.
Simulation of Wear for Revolute Joint Experiencing Periodic Load of a Gear Door Lock
Authors: Zhuang Xinchen , Yu Tianxiang , Sun Zhongchao , Yang Zhaohui , Guo Bozhi
Published: February 2017

Simulation of wear for a typical revolute joint under periodic load of a gear door lock is implemented with a three-dimension finite element model based on Archard’s wear law. Both the wear of the journal and the shaft of different materials are taken into account. The load and motion of the joint are acquired by the dynamic solution of the mechanism as the inputs of wear simulation. Displacements of the nodes experiencing wear are governed by the user subroutine UMESHMOTION in the finite-element code ABAQUS by which the direction of wear and wear depth are calculated. ALE adaptive meshing technology has been used to maintain a high-quality mesh. An effective adaptive extrapolation method is presented to minimize computational time and keep the accuracy by the processor algorithm. In the last part, the influence of clearances on the simulation of wear is investigated with the developed model.