bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Study on the Reduction of NOx Emissions From Pulse Detonation Combustion
Authors: Djordjevic Neda , Hanraths Niclas , Gray Joshua , Berndt Phillip , Moeck Jonas
Published: October 2017

A change in the combustion concept of gas turbines from conventional isobaric to constant volume combustion, such as in pulse detonation combustion (PDC), promises a significant increase in gas turbine efficiency. Current research focuses on the realization of reliable PDC operation and its challenging integration into a gas turbine. The topic of pollutant emissions from such systems has so far received very little attention. Few rare studies indicate that the extreme combustion conditions in PDC systems can lead to high emissions of nitrogen oxides (NOx). Therefore, it is essential already at this stage of development to begin working on primary measures for NOx emissions reduction if commercialization is to be feasible. The present study evaluates the potential of different primary methods for reducing NOx emissions produced during PDC of hydrogen. The considered primary methods involve utilization of lean combustion mixtures or its dilution by steam injection or exhaust gas recirculation. The influence of such measures on the detonability of the combustion mixture has been evaluated based on detonation cell sizes modeled with detailed chemistry. For the mixtures and operating conditions featuring promising detonability, NOx formation in the detonation wave has been simulated by solving the one-dimensional (1D) reacting Euler equations. The study enables an insight into the potential and limitations of considered measures for NOx emissions reduction and lays the groundwork for optimized operation of PDC systems.
Quantitative Assessment of Phase Change Material Utilization for Building Cooling Load Abatement in Composite Climatic Condition
Authors: Saxena Rajat , Biplab Kumar , Rakshit Dibakar
Published: October 2017

The global trend of energy consumption shows that buildings consume around 48% of the total energy, of which, over 50% is for heating and cooling applications. This study elucidates on cooling load reduction with phase change material (PCM) incorporation in a building envelope. PCM provides thermal shielding due to isothermal heat storage during phase change. PCM selection depends upon its phase change temperature, thermal capacity, and thermal conductivity, as they play a vital role in assessing their impact on energy conservation in buildings. The uniqueness of this study underlies in the fact that it focuses on the utilization of PCM for New Delhi (28.54°N, 77.19°E) climatic conditions and adjudges the suitability of three commercially available PCMs, based on the overall heat load reduction and their characteristic charging/discharging. The study aims at finding an optimum melting and solidification temperature of the PCM such that it may be discharged during the night by releasing the heat gained during the day and mark its suitability. The results of mathematical modeling indicate that as per the design conditions, the melting/solidification temperature of 34 °C is suitable for New Delhi to absorb the peak intensity of solar irradiation during summer. Based on the thermophysical properties in literature (Pluss Advanced Technologies Pvt. Ltd., 2015, “Technical Data Sheet of savE® HS29, PLUSS-TDS-DOC-304 Version R0,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India. Pluss Advanced Technologies Pvt. Ltd., 2015, “Technical Data Sheet of savE® OM32, PLUSS-TDS-DOC-394 Version R0,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India. Pluss Advanced Technologies Pvt. Ltd., 2012, “Technical Data Sheet - savEVR HS34, Doc:305,” Pluss Advanced Technologies Pvt. Ltd., Gurgaon, India), mathematical modeling showed HS34 to be suitable for New Delhi among the three PCMs. To ratify this, characteristic charging and discharging of HS34 is tested experimentally, using differential scanning calorimeter (DSC). The results showed that HS34 is a heterogeneous mixture of hydrated salts having super-cooling of 6 °C, reducing its peak solidification temperature to 30.52 °C during the cooling cycle also making it unsuitable for peak summers in New Delhi.
Sizing of a Photovoltaic-Wind-Oil Shale Hybrid System: Case Analysis in Jordan
Authors: AL-Ghussain Loiy , Taylan Onur , Fahrioglu Murat
Published: October 2017

The integration between renewable energy systems (RESs) and oil shale system ensures reliable power generation source with a competitive energy generation cost when compared to costs of conventional systems. In addition, this integration will prevent considerable amount of CO2 emissions. This study aims to determine the size of a grid-tied hybrid system in Al-Tafilah, Jordan that maximizes the yearly overall fraction of demand met with levelized cost of electricity (LCOE) equal to or lower than the local cost of electricity generation. In addition, the effect of the integration of lithium-ion batteries as short-term energy storage systems (ESSs) will be investigated in addition to the effect of carbon social cost on the economics of the system. The maximum FH by the hybrid system in Al-Tafilah is 97.2% with ESS and 96.9% without ESS where 70.4% of the demand is met by the 12 MW oil shale system; however, to achieve these fractions, enormous installed capacity of photovoltaic (PV) and wind is required where 99% of the energy production is excess and LCOE is larger than COEcon. The maximum FH with LCOE equals to COEcon can be achieved by 12 MW oil shale, 3.5 MW PV, and 6 MW wind turbines without ESS. Such size will have FH of 87.23%, capacity factor of 46.1%, RES fraction of 16.9%, net present value (NPV) of 34.8 million USD, and a payback period of 4.8 years.
Scenario-Based Multi-Objective Optimization of an Air-Based Building-Integrated Photovoltaic/Thermal System
Authors: Khaki Mahsa , Shahsavar Amin , Khanmohammadi Shoaib
Published: October 2017

In this paper, a genetic algorithm-based multi-objective optimization of a building-integrated photovoltaic/thermal (BIPV/T) system is carried out to find the best system configurations which lead to maximum energetic and exergetic performances for Kermanshah, Iran climatic condition. In the proposed BIPV/T system, the cooling potential of ventilation and exhaust airs are used in buildings for cooling the PV panels and also heating the ventilation air by heat rejection of PV panels. Four scenarios with various criteria in the form of system efficiencies and useful outputs are considered to reflect all possible useful outputs in the optimization procedure. This study models a glazed BIPV/T system with various collector areas (Apv=10,15,25,and30m2) and different length to width ratio (L/W=0.5,1,1.5,and2) to determine the optimum air mass flow rate, bottom heat loss coefficient, depth of the channel as well as the optimum depth of the air gap between PV panel and glass cover that maximize two defined objective functions in different scenarios. Results showed that using fourth scenario (with the annual total useful thermal and electrical outputs as objective functions) and first scenario (with the annual average first- and second-law efficiencies as objective functions) for optimizing the proposed BIPV/T system leads to the highest amount of useful thermal and overall outputs, respectively. Moreover, it was concluded that, if the electrical output of the system is more important than the thermal output, the first scenario gives better results.
Prediction of Blunting Area of Abrasive Grains on a Grinding Wheel
Authors: Dyakonov Aleksandr A. , Ardashev Dmitrii V.
Published: October 2017

The article presents the results of calculating the blunting area of abrasive grains of grinding wheels, determined in accordance with the previously developed model. The mathematic model of the size of the blunting area of an abrasive grain considers the main mechanisms of its wear—mechanical and physicochemical. These mechanisms are taken into account in the model. For the first time, the kinetic theory of strength was used for determining the mechanical wear of abrasive grain. The mass transfer theory was used to study the physicochemical wear: coefficients of chemical affinity with the abrasive material are experimentally defined for the assortment of workpiece materials. The developed mathematic model is a multiple-factor one and this will allow to predict the size of wear of the abrasive wheel for different technological conditions. Also, the article presents the experimental method for determining the blunting area of abrasive grains of grinding wheels, which allows making a direct measurement of wear parameters of grinding wheels. The main parameter of grinding wheel wear is the length of the blunting area of the grain, which was measured out in the direction of the cutting speed vector. The grinding wheels of different graininess were studied—F60 and F46. The grinding wheel working surface was studied by numerical photos and microscope. The results of these experiments have confirmed the adequacy of the design model.
Transient Heat Transfer in an Out-of-Pile SCWR Fuel Assembly Test at Near-Critical Pressure
Authors: Schulenberg Thomas , Li Hongbo
Published: October 2017

While supercritical water is a perfect coolant with excellent heat transfer, a temporary decrease of the system pressure to subcritical conditions, either during intended transients or by accident, can easily cause a boiling crisis with significantly higher cladding temperatures of the fuel assemblies. These conditions have been tested in an out-of-pile experiment with a bundle of four heated rods in the supercritical water multipurpose loop (SWAMUP) facility coconstructed by CGNPC and SJTU in China. Some of the transient tests have been simulated at KIT with a one-dimensional (1D) matlab code, assuming quasi-steady-state flow conditions, but time dependent temperatures in the fuel rods. Heat transfer at supercritical and at near-critical conditions was modeled with a recent look-up table of Zahlan (2015, “Derivation of a Look-Up Table for Trans-Critical Heat Transfer in Water Cooled Tubes,” Ph.D. dissertation, University of Ottawa, Ottawa, ON, Canada.), and subcritical film boiling was modeled with the look-up table of Groeneveld et al. (2003, “A Look-Up Table for Fully Developed Film Boiling Heat Transfer,” Nucl. Eng. Des., 225(1), pp. 83–97.). Moreover, a conduction controlled rewetting process was included in the analyses, which is based on an analytical solution of Schulenberg and Raqué (2014, “Transient Heat Transfer During Depressurization From Supercritical Pressure,” Int. J. Heat Mass Transfer, 79(12), pp. 233–240.). The method could well reproduce the boiling crisis during depressurization from supercritical to subcritical pressure, including rewetting of the hot zone within some minutes, but the peak temperature was somewhat under-predicted. Tests with a lower heat flux, which did not cause such phenomena, could be predicted as well. In another test with increasing pressure, however, a boiling crisis was also observed at a heat flux, which was significantly lower than the critical heat flux (CHF) predicted by the CHF look-up table of Groeneveld et al. (2007, “The 2006 CHF Look-Up Table,” Nucl. Eng. Des., 237(15–17), pp. 1909–1922.). The paper is summarizing the physical models and the numerical approach. Comparison with experimental data is used to discuss the applicability of the method for the design of supercritical water-cooled reactors (SCWR).
Effects of Thickness on the Responses of Piezoresponse Force Microscopy for Piezoelectric Film/Substrate Systems
Authors: Wang J. H. , Chen C. Q.
Published: October 2017

Piezoresponse force microscopy (PFM) extends the conventional nano-indentation technique and has become one of the most widely used methods to determine the properties of small scale piezoelectric materials. Its accuracy depends largely on whether a reliable analytical model for the corresponding properties is available. Based on the coupled theory and the image charge model, a rigorous analysis of the film thickness effects on the electromechanical behaviors of PFM for piezoelectric films is presented. When the film is very thick, analytical solutions for the surface displacement, electric potential, image charge, image charge distance, and effective piezoelectric coefficient are obtained. For the infinitely thin (IT) film case, the corresponding closed-form solutions are derived. When the film is of finite thickness, a single parameter semi-empirical formula agreeing well with the numerical results is proposed for the effective piezoelectric coefficient. It is found that if the film thickness effect is not taken into account, PFM can significantly underestimate the effective piezoelectric coefficient compared to the half space result. The effects of the ambient dielectric property on PFM responses are also explored. Humidity reduces the surface displacement, broadens the radial distribution peak, and greatly enlarges the image charge, resulting in reduced effective piezoelectric coefficient. The proposed semi-empirical formula is also suitable to describe the thickness effects on the effective piezoelectric coefficient of thin films in humid environment. The obtained results can be used to quantitatively interpret the PFM signals and enable the determination of intrinsic piezoelectric coefficient through PFM measurement for thin films.
A New Family of Deployable Mechanisms Derived From Two-Layer and Two-Loop Spatial Linkages With Five Revolute Pair Coupling Chains
Authors: Cao Wen-ao , Yang Donghao , Ding Huafeng
Published: October 2017

This paper aims to construct a novel family of deployable mechanisms from a class of two-layer and two-loop spatial linkages, each of which consists of an eight revolute pair (8R) single-loop linkage connected by a 5R serial chain. First, structural characteristics of the class of linkages as deployable units are analyzed and illustrated. Then, the two-layer and two-loop spatial linkages with 5R chains satisfying the structural characteristics are systematically synthesized. Mobile assembly modes between deployable units are established based on degree-of-freedom (DOF) analysis. Finally, a family of single DOF deployable mechanisms is constructed based on the synthesized deployable units and the established assembly modes. The derived deployable mechanisms have the characteristic of the umbrella-like structure, and they have various mesh shapes, which can meet different kinds of application requirements.
Experimental and Modeling Study of C1–C3 Hydrocarbon Ignition in the Presence of Nitric Oxide
Authors: Gokulakrishnan Ponnuthurai , Fuller Casey C. , Klassen Michael S.
Published: October 2017

Nitric oxide (NO) produced during combustion will be present in vitiated air used in many devices. An experimental and modeling investigation of the effect of NO on the ignition of C1–C3 hydrocarbon fuels, namely, CH4, C2H4, C2H6, and C3H6, is presented. These molecules are important intermediate species generated during the decomposition of long-chain hydrocarbon fuel components typically present in jet fuels. Moreover, CH4 and C2H6 are major components of natural gas fuels. Although the interaction between NOx and CH4 has been studied extensively, limited experimental work is reported on C2H4, C2H6, and C3H6. As a continuation of previous work with C3H8, ignition delay time (IDT) measurements were obtained using a flow reactor facility with the alkanes (CH4 and C2H6) and olefins (C2H4 and C3H6) at 900 K and 950 K temperatures with 15 mole% and 21 mole% O2. Based on the experimental data, the overall effectiveness of NO in promoting ignition is found to be: CH4 > C3H6 > C3H8 > C2H6 > C2H4. A detailed kinetic mechanism is used for model predictions as well as for reaction path analysis. The reaction between HO2 and NO plays a critical role in promoting the ignition by generating the OH radical. In addition, various important fuel-dependent reaction pathways also promote the ignition. H-atom abstraction by NO2 has significant contribution to the ignition of C2H4 and C2H6, whereas the reaction between NO2 and allyl radical (aC3H5) is an important route for the ignition of C3H6.
Multiphase Flow Performance Prediction Model for Twin-Screw Pump
Authors: Liu Peng , Patil Abhay , Morrison Gerald
Published: October 2017

This study is focused on the development and validation of an analytical model to predict the performance characteristics of multiphase flow twin-screw pump for wide range of operating conditions. A 200 HP, 635 gpm capacity multiphase flow twin-screw pump was tested with inlet pressure varying from 15 psig to 100 psig at gas void fraction (GVF) varying from 0% to 100% to validate the model. A new model is proposed to study the leakage flow in the twin screw pump. Adiabatic compressible flow is assumed in the circumferential clearance. The acceleration of the two-phase flow is taken into account in the new model. The change of Mach number of the leakage flow in the clearance and the possibility of choked flow at the outlet of the clearance was studied. Model provided important information about pressure distribution across the screw length, volumetric efficiency of the pump, and chocked flow condition. Model verification using experimental data concluded the paper.
Effects of Fluid Properties on Spray Characteristics of a Flow-Blurring Atomizer
Authors: Fisher Brian T. , Weismiller Michael R. , Tuttle Steven G. , Hinnant Katherine M.
Published: October 2017

In order to understand the reasons for the apparent benefits of using a flow-blurring (FB) atomizer in a combustion system, it is necessary to first examine fundamental spray characteristics under nonreacting conditions. Previous work on FB atomizers, however, has mostly involved only water and a relatively narrow range of parameters. In this study, a phase Doppler anemometry (PDA) instrument was used to characterize FB atomizer sprays and determine the effects of varying surface tension and viscosity of the liquid. Operating at room pressure and temperature (i.e., a “cold spray”), droplet sizes and velocities were measured for water, a water/surfactant mixture (lower surface tension), a water/glycerol mixture (higher viscosity), and glycerol (much higher viscosity). For all of the tested fluids, with the exception of pure glycerol, the FB atomizer produced small droplets (below 50 μm) whose size did not vary significantly in the radial or axial direction, particularly above a characteristic distance from the atomizer exit. Results show that the spray is essentially unaffected by a 4.5× decrease in surface tension or a 7× increase in viscosity, and that Sauter mean diameter (SMD) only increased by approximately a factor of three when substituting glycerol (750× higher viscosity) for water. The results suggest that the FB atomizer can effectively atomize a wide range of liquids, making it a useful fuel-flexible atomizer for combustion applications.
Flow Characteristics of Three-Dimensional Curved Wall Jets on a Cylinder
Authors: Kim Mirae , Kim Hyun Dong , Yeom Eunseop , Kim Kyung Chun
Published: October 2017

Three-dimensional (3D) curved wall jets are a significant topic in various applications related to local heat and mass transfer. This study investigates the effects of the impinging angle and Reynolds number with a fixed distance from the nozzle to the surface of a cylinder. The particle image velocimetry (PIV) method was used to measure the mean streamwise velocity profiles, which were normalized by the maximum velocity along the centerline of the impinging jet onto the cylinder. After the impingement of the circular jet, a 3D curved wall jet develops on the cylinder surface due to the Coanda effect. At a given Reynolds number, the initial momentum of the wall jet increases, and flow separation occurs further downstream than in normal impingement as the impinging angle increases. At a given impinging angle, flow separation is delayed with increasing Reynolds number. A self-preserving wall jet profile was not attained in the 3D curved wall jet. The turbulence intensity and the Reynolds shear stress were obtained to analyze the turbulence characteristics. The radial turbulence intensity showed similar tendencies to a two-dimensional (2D) curved wall jet, but the streamwise turbulence intensity was dissimilar. The Reynolds shear stress decreases downstream of the cylinder wall due to the decreased velocity and centrifugal force.
Particle Image Velocimetry Investigation of the Coherent Structures in a Leading-Edge Slat Flow
Authors: Richard Patrick R. , John Wilkins Stephen , Hall Joseph W.
Published: October 2017

Air traffic volume is expected to triple in the U.S. and Europe by 2025, and as a result, the aerospace industry is facing stricter noise regulations. Apart from the engines, one of the significant contributors of aircraft noise is the deployment of high-lift devices, like leading-edge slats. The unsteady turbulent flow over a leading-edge slat is studied herein. In particular, particle image velocimetry (PIV) measurements were performed on a scale-model wing equipped with a leading-edge slat in the H.J. Irving–J.C.C. Picot Wind Tunnel. Two Reynolds numbers based on wing chord were studied: Re = 6 × 105 and 1.3 × 106. A snapshot proper orthogonal decomposition (POD) analysis indicated that differences in the time-averaged statistics between the two Reynolds numbers were tied to differences in the coherent structures formed in the slat cove shear layer. In particular, the lower Reynolds number flow seemed to be dominated by a large-scale vortex formed in the slat cove that was related to the unsteady flapping and subsequent impingement of the shear layer onto the underside of the slat. A train of smaller, more regular vortices was detected for the larger Reynolds number case, which seemed to cause the shear layer to be less curved and impinge closer to the tail of the slat than for the lower Reynolds number case. The smaller structures are consistent with Rossiter modes being excited within the slat cove. The impingement of the shear layers on and the proximity of the vortices to the slat and the main wing are expected to be strong acoustic dipoles in both cases.
Estimation of Road Adhesion Coefficient Based on Tire Aligning Torque Distribution
Authors: Ma Biao , Lv Chen , Liu Yahui , Zheng Minghui , Yang Yiyong , Ji Xuewu
Published: October 2017

Road adhesion coefficient is an important parameter in vehicle active safety control system. Many researchers estimate road adhesion coefficient by total tire self-aligning torque (SAT, also called front-axle aligning torque), which obtains the average road adhesion coefficient of front wheels, thus leading large estimation error. In this paper, a novel estimation of road adhesion coefficient based on single tire SAT, which is obtained by tire aligning torque distribution, is brought forward. Due to the use of SAT, the proposed estimation method is available in steering only condition. The main idea of the proposed method is that road adhesion coefficient is estimated by single tire SAT instead of total tire SAT. The single tire SAT is closer to real tire torque state, and it can be obtained by aligning torque distribution, which makes use of the ratio for the aligning torque of front-left wheel and front-right wheel. Tire sideslip angle used in torque distribution is estimated by unscented Kalman filter (UKF). Two coefficients, including front-left and front-right tire-road friction coefficients, are estimated by iteration algorithm form single tire SAT. The final road adhesion coefficient is determined by a coefficient identification rule, which is designed to determine which tire-road friction coefficient as the final road adhesion coefficient. Both simulations and tests that use gyroscope/lateral accelerometer/global position system (GPS)/strain gauge are conducted, to validate the proposed methodology that can provide accurate road adhesion coefficient to vehicle active safety control.
Microstructures and Friction–Wear Behaviors of Cathodic Arc Ion Plated Chromium Nitride Coatings at High Temperatures
Authors: Shouyu Zhu , Dejun Kong
Published: October 2017

A chromium nitride (CrN) coating was deposited on YT14 cemented carbide using a cathodic arc ion plating (CAIP). The high temperature friction and wear of the obtained coating were investigated using a wear test. The results show that the Cr and N form the atom-rich zones in the coating. The average coefficient of friction (COF) of CrN coatings at 300 °C, 400 °C, and 500 °C is 0.50, 0.62, and 0.43, respectively. The wear mechanism of CrN coating at 300 °C and 400 °C is abrasive wear, and that at 500 °C is abrasive wear, accompanied by slight oxidation wear.
Effect of milling time on sliding friction and wear behavior of hot isostatically pressed titanium alloys Ti-6Al-4X(X=V, Nb Fe) for biomedical applications
Authors: Fellah Mamoun , Aissani Linda
Published: October 2017

The aim of the present research was focused on the study of the effect of replacing vanadium by niobium and iron on the tribological behavior of Hot Isostatic Pressed (HIPed) titanium alloy (Ti-6Al-4V) biomaterial, using a ball-on-disk type Oscillating tribometer, under wet conditions using physiological solution conditions (Ringer solution) in accordance with the ASTMG 99, ISO 7148-1:2012, and ASTM G 133–95 standards. The tests were carried out under a normal load of 6 N, with an AISI 52100 grade steel ball as a counter face. The morphological changes and structural evolution of the nanoparticle powders using different milling times (2, 6, 12 and 18 h) were studied. The morphological characterization indicated that the particle and crystallite size continuously decreases with increasing milling time to reach the lowest value of 4 nm at 18 hours milling. The friction coefficient and wear rate were lower in the samples milled at 18 h (0.226, 0.297 and 0.423) and (0.66 x10-2, 0.87x10-2 and 1.51x10-2 µm3.N-1.µm-1) for Ti-6Al-4Fe, Ti-6Al-4Nb and Ti-6Al-4V, respectively. This improvement in friction and wear resistance is attributed to the grain refinement at 18 hour milling. The Ti-6Al-4Fe samples showed good tribological performance for all milling times
Measurement and Prediction of the Journal Circumferential Temperature Distribution for the Rotordynamic Morton Effect
Authors: Tong Xiaomeng , Palazzolo Alan
Published: October 2017

The journal is the part of a shaft that is inside a fluid film bearing and is usually assumed to be circumferentially isothermal. Recent work has shown that under certain vibration conditions, a significant temperature difference (ΔT) can develop around the journal circumference. The ΔT may cause the shaft to bend leading to a synchronous vibration instability problem, termed the “Morton effect” (ME). A test rig was developed to verify the asymmetric journal temperature of the ME and its prediction using a five-pad tilting pad journal bearing (TPJB) operating with an eccentric shaft to replicate a circular vibration orbit. The bearing is tested at various conditions including: supply oil temperature at 28 °C and 41 °C, bearing operating eccentricities of zero and 32%Cb, and rotor speed up to 5500 rpm. The journal temperature distribution is recorded with 20 sensors located around the journal circumference, and the measurements provide a benchmark for predictions from a time transient model with the three-dimensional (3D) fluid and solid finite element method (FEM), and with a simplified ME prediction approach using only steady-state results. The test results follow the predictions exhibiting a sinusoidal-like temperature profile around the circumference with an angular lag of the hot spot location behind the high spot location (angular position on the rotor that arrives at the minimum film thickness condition each rotation) by a speed-dependent angle. Increasing the supply oil temperature reduced the journal ΔT, while increasing the bearing operating eccentricity increased the journal ΔT. The agreement between the test and predicted results is significantly better for the 3D FEM transient model than for the steady-state-based model in terms of journal ΔT and hot spot position. An improved version of the latter approach is proposed and yields significantly better correlation with the test measurements.
Vibrational Response of Initially Deformed Bistable Microbeams Under the Combined Effect of Mechanical Shock Loads and Electrostatic Forces
Authors: Alqasimi Jihad E. , Ouakad Hassen M.
Published: October 2017

This paper focuses on the influence of sudden drop tests on the nonlinear structural behavior of electrically actuated bi-table shallow microelectromechanical system (MEMS) arches. The assumed structure consists of an initially bell-shaped doubly clamped microbeam with a rectangular cross section. The Euler–Bernoulli beam theory is assumed to model the nonlinear structural behavior of the bistable system under the combined effect of both the direct current (DC) actuating load and the shaking waves. Moreover, the structural model takes into account both geometric midplane stretching and electric actuation nonlinear terms. A multimode Galerkin-based decomposition is used to discretize the beam equations to extract a reduced-order model (ROM). The convergence of the ROM simulations are first verified and furthermore compared to published experimental data. A thorough ROM parametric study showed that the effect of increasing the shallow arch initial rise alter drastically the system behavior from undergoing a uninterrupted snap-through motion to a sudden snap-through instability. Moreover, the arch rise relationship with its shock spectrum response (SSR) is investigated and it was concluded that as increasing the rise value can cause the system to collapse under the combined DC and shock wave loadings if the shock wave duration is lower or near the system fundamental natural period. All the presented graphs in this investigation represent some robust numerical approaches and design tools to help MEMS designers in improving both the reliability and efficiency of these bistable-based microdevices under shaking dynamic environments.
An Experimental Research on the Force and Energy During the Sapphire Sawing Using Reciprocating Electroplated Diamond Wire Saw
Authors: Huang Hui , Li Xixi , Xu Xipeng
Published: October 2017

This study investigated the sawing of A-plane and C-plane sapphires using the reciprocating diamond wire saw. The influences of process parameters and sapphire crystal structure on sawing force were experimentally researched. The experimental results indicated that, in sapphire sawing process, the sapphire crystal structure, the wire speed, and the feed rate had effects on the tangential sawing forces, and the tangential forces had good linear relationships with the material removal rates (MRRs). The specific sawing energies in the stable stage were clearly smaller than in the unstable stage.
Numerical Investigation of Electro-Kinetic Effect on Pipe-Soil Interaction
Authors: Joshua Hakuri Nwen , Kara Fuat
Published: October 2017

The soft soil content and the high pressure and high temperature (HP/HT) of the operating fliud significantly account for the displacement of subsea pipelines. The abiltiy of the pipeline to resist displacement depents on the soil strength. Increasing the pipe-soil resistance will significantly reduced the pipeline displacement. One method used to increase soil shear strength is the Electro-kinetic (EK) process. This is applied to increase strength of onshore and offshore soil foundations. This paper uses ABAQUS software tool to investigate EK effect on axial displacement of pipeline due to pipe-soil interaction. Studies on both EK treated soil and non-EK treated soil are conducted and compared. Electro-osmosis using the varous flow process is demonstrated and effectively validated. The paper also demontrated the dynamic process due to axial pulling of the pipeline. The resistance developed for both conditions were determined and compared. Due to axial pulling of the pipeline from the soil, the present numerical results shows a remarkable increase of over 100% in frictional resistance to pipeline displacement.
Iceberg Detection in Low Visibility Conditions via Infra-Red Sensors: Processing and Modelling of Field Data
Authors: Bouquet Grégory , Schulerud Helene , Scibilia Francesco
Published: October 2017

This article deals with Short Wave Infra-Red (SWIR) and Long Wave Infra-Red (LWIR) imaging sensors for detecting icebergs in harsh metocean conditions. Field data acquired during the Statoil Offshore Newfoundland Research Expedition 2015 (ONRE15) is analyzed. The analysis is supported by a numerical modelling study which aims at simulating the optical properties of ice and water combined with the radiation transfer in the Infra Red.
Economical Proposal for an Offshore Logistic Hub
Authors: Asgari Peyman , Fernandes Antonio Carlos
Published: October 2017

Oil exploration in the pre-salt, mainly in the SANTOS BASIN, has increased significantly and as results increasing the number of thousands of people commute to offshore platforms in Brazil is inevitable. The presence of a remote terminal, the so-called HUB, adjacent to the platforms, not only reduces the shipment costs, but also increases the speed of commuting. The present work addresses the feasibility of utilizing a ship shape hull as an alternative logistic HUB. The present work analyzes the hull as a rigid body receiving mostly transversal waves and operating as a floating breakwater in deep water with a central turret. The crew boat is a HSV, which will also be included in the investigation. As a continuation of the previous study of the author in 2015, the relative vertical motion between two bodies is analyzed in (four) different configurations and angles of incoming waves by the panel method code in frequency domain. Finally, having in mind operation limits and criterion, operation probabilities are evaluated. Four configurations are considered to be analyzed numerically on the relative vertical motion between two bodies in different Configurations and different angles of incoming waves by a panel method code for frequency domain. Finally, operation probabilities are studied according to the operation limits and criterion.
Benchmark Study of Five Optimization Algorithms for Weather Routing
Authors: Wang Helong , Mao Wengang , Eriksson Leif
Published: October 2017

Safety and energy efficiency are two of the key issues in the maritime transport community. A sail plan system, which combines the concepts of weather routing and voyage optimization, are recognized by the shipping industry as an efficient measure to ensure a ship’s safety, gain more economic benefit, and reduce negative effects on our environment. In such a system, the key component is to develop a proper optimization algorithm to generate potential ship routes between a ship’s departure and destination.

In the weather routing market, four routing optimization algorithms are commonly used. They are the so-called modified Isochrone and Isopone methods, dynamic programming, threedimensional dynamic programming, and Dijkstra’s algorithm, respectively. Each optimization algorithm has its own advantages and disadvantages to estimate a ship routing with shortest sailing time or/and minimum fuel consumption. This paper will present a benchmark study that compare these algorithms for routing optimization aiming at minimum fuel consumption. A merchant ship sailing in the North Atlantic with full-scale performance measurements, are employed as the case study vessels for the comparison. The ship’s speed/power performance is based on the ISO2015 methods combined with the measurement data. It is expected to demonstrate the pros and cons of different algorithms for the ship’s sail planning.
Ditch Magnet Performance
Authors: Strømø Kjartan M. , Saasen Arild , Hodne Helge , Pallin Jan Egil , Aaker Gudmund
Published: October 2017

Magnetic shielding of the Measurement While Drilling (MWD) directional tools and damages to mud pumps, down-hole tools and casing/drill-pipe and difficulties in understanding logging results are some of the main problems caused by steel and magnetic contaminated drilling fluids. In order to have these problems significantly reduced, all the magnetic contaminants should ideally be removed from the drilling fluid by the use of ditch magnets. Hence, the magnets and their ability to remove magnetic waste from the drilling fluid was evaluated by field evaluations.

Data from a field test of a new ditch magnet system where all the drilling fluid is forced to flow into an area with a strong magnetic fields have been compared with data from an operation with a traditional ditch magnet system in order to see if there are any significant differences in the total amount of magnetic waste material collected from the two systems. It is shown how drilling length, inclination and casing size may affect the production of magnetic debris entering the drilling fluid, and hence, show the well construction dependence of the ditch magnet performance.
Wave Energy Conversion Efficiency of the Dual Cylindrical Caisson Breakwaters Embodying an OWC With a Semi-Arc Inlet on Outer Wall
Authors: Chen Jing , Wang Yongxue , Wang Guoyu , Cai Li
Published: October 2017

In the paper, the integrated structure of a dual cylindrical caisson embodying an OWC device is designed. The seaside hemi-toroidal column of the dual cylinder caisson is an air chamber for water column oscillation while the leeside hemi-toroidal column of the dual cylinder is filled with sand for caisson stability. Experimental investigations were carried out on the performance of the OWC at different water depths, wave heights and wave periods, as well as on the layout of the caissons and the nozzle area ratio. Experimental results show that the water depth has significant effect on the wave energy conversion efficiency of dual cylindrical caisson breakwaters embodying an OWC. The new structure proposed as a breakwater or revetment structure especially arranged in a one-third convex arc has advantages in collecting more energy and creating a fine landscape environment.
Theoretical Basis for Prediction of Drilling Fluid Removal in Annuli
Authors: Saasen Arild , Lund Bjørnar , Ytrehus Jan David
Published: October 2017

Displacement processes are part of several drilling fluid operations. These operations include non-trivial items like changing from water based drilling fluid to oil based or opposite, casing cleaning operations, change to completion fluids or displacement operations during cementing. Among these operations, cementing is the most important and difficult because the scope is to create a permanent barrier and permanent zonal isolation in operations involving only limited volumes of fluids and slurries.

Empirical guidelines have been implemented to improve displacement processes in wells. Analytical and numerical models are frequently used. The models seem to be efficient in predicting pressure losses. However, they seem to be incapable of accurately predict the displacement efficiency. Laboratory experimental results have been evaluated and have been scaled up to for field application with variable success rate. These difficulties are caused by the presence of too many length scales or other dimensional scales.
Data-Driven Real-Time Decision Support and its Application to Hybrid Propulsion Systems
Authors: Reite Karl-Johan , Ladstein Jarle , Haugen Joakim
Published: October 2017

This paper describes a method for providing real time decision support based on measurements rather than optimizing a mathematical model. The proposed method is thus beneficial for systems for which the modelling would be inaccurate, the dynamics and complexity of the system would make it difficult to optimize in real time, or the risk of returning local minima is not acceptable.

The proposed method is implemented on four fishing vessels. These vessels are complex and give the skipper many choices related to how the vessel is operated. The developed tool advises the crew on in real time on operational decisions, particularly on the use of various diesel electric and diesel mechanic propulsion modes, including decisions such as the use use of shaft generator, direct coupling between main engine and propeller or not, propeller pitch, etc. This will presumably reduce both fuel consumption and emissions of CO2 and NOX.

Some examples of obtainable results from both onshore analyses and the onboard application are presented to demonstrate the methods applicability.
The Study of a New Concept of Flexible Pipe With Carbon Fiber/Epoxy Reinforced Inner Sheath
Authors: Zhou Chongyao , Huang Zhiming , Kang Yongtian , Zhang Dagang , Ye Naiquan , Sævik Svein
Published: October 2017

Flexible pipe has been widely used in offshore industry for many years. The traditional composite structure of flexible pipe consists of many layers, including multiple metallic layers, such as tensile armor, pressure armor and carcass, as well as nonmetallic layers, such as sheath and liner. Typical flexible pipe is heavy and requires complex manufacturing process, especially pressure armor and carcass manufacturing. Therefore, there is a desire to find a replacement to pressure armor and carcass. With the recent development of a new composite material with lighter weight and higher strength, it now becomes possible. This new composite material is called epoxy compounded carbon fiber (EP/CF). Carbon fiber is 10 times stronger than steel, while it is only 1/5 of the steel weight. Epoxy protects carbon fiber from environmental conditions such as high temperature and corrosion, also bond carbon fiber together and help to redistribute the loading between carbon fibers.

This paper is to present a new concept of flexible pipe by applying the EP/CF material to flexible design. In this new flexible concept, EP/CF is used to strengthen the inner sheath by surface activation treatment of sheath material. This provides excellent hoop strength to resist the inner pressure, hence provides a good replacement to the pressure armor and carcass.

A new FEA analysis method with ABAQUS is also presented in this paper. In the analysis approach, all helix fibers are modelled using predefined beam element, and EP/CF reinforced inner sheath is modeled using laminated composite shell. Nonlinear FEA analysis is carried out in ABAQUS to investigate the tension and bending behavior of flexible pipe with reinforced inner sheath, including the performance of inner pressure resistance, which is one of the key performances. Analysis is also carried out to study the benefit of using EP/CF on outer sheath reinforcement for collision protection. Lastly, the economics and feasibility of this concept are discussed, and conclusions are drawn.
Developments in Testing and Manufacture of Thick-Walled Pipe
Authors: Walker Alastair , Chee Jayden , Roberts Peter
Published: October 2017

Over the past 20 years there has been a considerable development of the capability to design and manufacture thick walled pipe to manufacture pipelines to operate in ultra-deep water. Design guidance is available in DNV OS F101 [1] in which the safety from pressure collapse failure during pipeline installation is determined by the use of a safety factor. The safety factor has been calibrated using the Load and Resistance Factor Design (LRFD) method in comparison with collapse pressure test results available at the time of preparation of DNV guidance. Because of the huge financial implications of loss of a very long pipeline during installation in ultra-deep water it has been the practice further to base the design of such a pipeline on specific pipe joint collapse tests in conjunction with the DNV information. Pressure testing full-scale pipe joints is an expensive undertaking that requires a suitable pressure chamber. Only a few chambers capable of applying pressures corresponding to very deep water are available in the world and transport of the pipes from the pipe mill to a suitable test facility may be very inconvenient and certainly expensive. This paper describes an alternative approach which could provide data that would enable the preparation of a safe approach specific to the pipeline diameter and design water depth. The approach could enable optimisation of the pipe design, particularly the pipe wall thickness. The proposed method is based on replacing costly full scale pipe tests by corresponding tests on ring specimens cut and machined from manufactured pipe joints. The proposal to use ring testing as the basis for design has been included successfully in the design of pipe for a recent ultra-deep water project [2]. The paper describes equipment used to subject the rings to external pressure and reports on tests carried out to validate the correspondence between the ring collapse pressure and that for the pipe joint from which the ring was obtained. Based on results from such tests it is concluded in this paper that ring pressure collapse testing is indeed a valid method to use as the basis for the design pipes in the next stage of ultra-deep water, i.e. increasing the capability to install pipeline in water depths down to 3500m from the current maximum level of 2500m.
A New Type of Collapsible Wing Sail and its Aerodynamic Performance
Authors: Li Dongqin , Li Guohuan , Dai Jingjing , Li Peng
Published: October 2017

In recent years, research on energy saving and emission reduction has been given much attention and the rise in the usage of renewable energy technologies has been remarkable. Through the use of wind energy, the goals of energy saving and emission reduction could be realized for ocean-going ships. Sail assisted technology is undoubtedly safe and reliable, but also is suitable for the current ship transportation. In order to ensure the safety of the ship and promote the full usage of clean energy at sea, a new type of ship propulsion-assisted wing sail was proposed innovatively. Focusing on the automatic and flexible structural features of the wing sail, this new type of collapsible wing sail is designed to increase the propulsion efficiency by enlarging the wing sail area in the transverse and vertical directions when the wind conditions get available. In the meanwhile, it can be folded up automatically in the poor weather condition and reduce the wind area in the transverse section and improve the sailing safety for ship. This new wing sail is composed of three parts: the main wing, the front wing and the back wing. Based on the technology of Computational Fluid Dynamics (CFD), the sail parameters such as gaps and rotation angles between different wings were investigated and the best setup parameters with excellent aerodynamic performance were fixed. Through the numerical simulation methods, the results of lift coefficients and drag coefficients for the new wing sail under different attack angles were obtained and also compared with the traditional arc-shaped rigid sail and variable-camber sail which was innovatively proposed by Qiao Li in 2015. From the viewpoint of the sailing performance of the vessel, our results demonstrate that this new type of wing sail has good aerodynamic performance and can reduce fuel costs for commercial vessels.