bluuebunny/crossref_metadata_2025 huggingface dataset:
Participatory Noise Mapping: Harnessing the Potential of Smartphones Through the Development of a Dedicated Citizen-Science Platform
Authors: King Eoin A. , Tatoglu Akin , Celmer Robert D.
Published: January 2018

This paper presents results of an ongoing project which aims to develop a purpose-built platform for using smart phones as alternative to sound level meters for citizen-science based environment noise assessment.

In order to manage and control environmental noise effectively, the extent of the problem must first be quantified. Across the world, strategic noise maps are used to assess the impact of environmental noise in cities. Traditionally, these maps are developed using predictive techniques, but some authors have advocated the use of noise measurements to develop more reliable and robust noise maps.

If adopted correctly, smartphones have the capability to revolutionize the manner in which environmental noise assessments are performed. The development of smartphone technology, and its impact on environmental noise studies, has recently begun to receive attention in the academic literature. Recent research has assessed the capability of existing smartphone applications (apps) to be utilized as an alternative low-cost solution to traditional noise monitoring. Results show that the accuracy of current noise measurement apps varies widely relative to pre-specified reference levels. The high degree of measurement variability associated with such apps renders their robustness questionable in their current state. Further work is required to assess how smartphones with mobile apps may be used in the field and what limitations may be associated with their use.

To over come the above issues, this project is developing a platform specifically for citizen science noise assessment. The platform consists of a smartphone app that acquires a sound signal and transfers the data to a server via a web based API for post processing purposes. This then returns key information to the user, as well as logging the data for use in a massive noise mapping study. The structure of the proposed platform maintains a clear separation between client (phone) and server. This approach will allow implementation of future open source client side apps for both Android and iOS operating systems.
Assessing Near-Wall Hemodynamics of Blood Flow in the Left Anterior Descending Segment of the Left Coronary Artery Using Computational Fluid Dynamics
Authors: Asiruwa John J. , Propst Aaron M. , Gent Stephen P.
Published: January 2018

The objective of this study was to computationally investigate the flow mechanics and the near-wall hemodynamics associated with the different take-off angles in the left coronary artery of the human heart. It is hypothesized that increasing the take-off angles of the left coronary artery will significantly increase or decrease the likelihood of plaque (atherosclerosis) buildup in the left coronary artery bifurcations. Specifically, this study quantified the effects of the varying take-off angles on the branches along the left anterior descending (LAD) of the left coronary artery using computational fluid dynamics (CFD) simulations. The study compared five test cases of the different take off-angles of the left coronary artery (LCA) and four different branch angles between the LAD and the left circumflex (LCx). It also considered the branch angles of the coronary artery downstream the LAD. The LCA inlet boundary conditions was set as a pulsatile mass flow inlet and flow split ratios were set for the outlets boundary conditions. The nature of blood pulsatile flow characteristic was accounted for and the properties of blood which include the density (1,050 kg/m3) and dynamic viscosity (0.0046 Pa-s) were obtained from previous research.

The results from the simulations are compared using established scales for the parameters evaluated. The parameters evaluated were: (i) Oscillatory Shear Index (OSI); which quantifies the extent in which the blood flow changes direction during a cardiac cycle (ii) Time Average Wall Shear Stress (TAWSS); which quantifies the average shear stress experienced by the wall of the artery and (iii) Relative Residence Time (RRT); which quantifies how long blood spends in a location along the artery during blood flow. These parameters are used to predict the likelihood of blood clots, atherosclerosis, endothelial damage, plaque formation, and aneurysm in the blood vessels. The data from the simulations were analyzed using functional macros to quantify and generate threshold values for the parameters.
Investigating the Effects of Stent-Graft Structural Features Using Computational Fluid Dynamics
Authors: Looyenga Eric M. , Propst Aaron M. , Gent Stephen P.
Published: January 2018

The objective of this study was to assess the effects structural features of endovascular stent-grafts used to repair abdominal aortic aneurysms (AAA) have on the flow mechanics and near-wall hemodynamics using Computational Fluid Dynamics (CFD) simulations. This research compared two test case model representations: 1) a stent graft that included the wire struts in the graft walls, and 2) a stent graft that excluded the struts in the computational mesh. The two computer-aided design models were created to represent a bifurcated stent graft in the abdominal aorta, with the stent beginning in the thoracic region of the aorta and branching into the common iliac arteries. The geometries were imported as surface meshes into a commercially available CFD solver. Both models account for viscous pulsatile blood flow of the cardiac cycle using blood properties gathered from previous research. Results of the two simulations were compared by using established metrics, including oscillating shear index (OSI), time average wall shear stress (TAWSS), and relative residence time (RRT), all of which are used to predict the likelihood of clot formation, endothelial damage, and device failure. Scalar and vector scenes allow for visualization, and data was exported for quantifying threshold results of the parameters. Due to the expense of stent grafts and the risks involved with clinical trial, CFD modeling is becoming more prominent in endovascular repair of aneurysms. The overarching goal of this study is to enhance current models of stent grafts, which can potentially be used to complement clinical trial for stent graft development.
Life Prediction of a Turbine Engine Blade to Disk Attachment Under Coupled Thermo-Mechanical Fatigue
Authors: Naboulsi Sam
Published: January 2018

Life prediction of turbine engines is crucial part of the management and sustainment plan to aircraft jet engine. Fretting is one of the primary phenomena that leads to damage or failure of blade-disk attachments. Fretting is often the root cause of nucleation of cracks at attachment of structural components at or in the vicinity of the contact surfaces. It occurs when the blade and disk are pressed together in contact and experience a small oscillating relative displacement due to variations in engine speed and vibratory loading. It is a significant driver of fatigue damage and failure risk of disk blade attachments. Fretting is a complex phenomenon that depends on geometry, loading conditions, residual stresses, and surface roughness, among other factors. These complexities also go beyond the physics of material interactions and into the computational domain. This is an ongoing effort, and the Author has been working on computationally modeling the fretting fatigue phenomenon and damage in blade-disk attachment. The model has been evolving in the past few years, and it has been addressing various fretting conditions. The present effort includes the thermal effect and temperature fluctuation during engine operation, and it models the effects of blade to disk attachment’s thermal conditions and its influence on fretting fatigue damage. It further extends the earlier model to include a coupled fatigue damage model. It allows modeling higher speeds and longer durability associated with blade disk attachments. Finally, to demonstrate its capabilities and taking advantage of experimental validation model, the most recent numerical simulations will be presented.
Creep Behavior of a Solder Paste With Bi Addition
Authors: Ribeiro Pedro E. , Soares Delfim F. , Cerqueira Maria F. , Teixeira Senhorinha F. , Barros Daniel A. , Teixeira José C.
Published: January 2018

A common failure mode of electronic PCB’s is the appearance of cold solder joints between the component and PCB, during product life. This phenomenon is related to solder joint fatigue and is attributed mainly to the mismatch of the coefficients of thermal expansion (CTE) of component-solder-PCB assembly. Although some experiments show that newer lead-free tin-silver-copper (Sn-Ag-Cu, or SAC) solders perform better than the older SnPb ones, with today’s solder joint thickness decreasing and increasing working temperatures, among others, the stresses and strains due to temperature changes are growing, leading to limited fatigue life of the products. As fatigue life decreases with increasing plastic strain, creep occurrence should have significant impact, especially during thermal cycles. In order to improve mechanical properties, but also as an attempt to reduce maximum reflow cycle temperatures due to component damage and production costs, various SAC solder alloying additives are being considered to use in industrial production facilities. Solder paste producers are proposing new products based on new solder paste formulations, but the real life effects on thermo-mechanical performance aren’t well known at the moment. In this paper a dynamic mechanical analyser (DMA) is used to study the influence of Bismuth (Bi) addition, up to 5 wt %, on SAC405 solder paste, in terms of creep behaviour. Creep tests were made on three-point-bending configuration, isothermally at 30 °C, 50 °C and 75 °C, and three different stresses of 3, 5 and 9 MPa. The results shown not only a significant Bi concentration influence on creep behaviour but also a noticeable temperature dependence.
Analytical Modelling of Friction Along Tool Chip Interface for Inconel 718
Authors: Kumar Abhishek , Kuriachen Basil , Ontela Surender
Published: January 2018

Inconel 718 is gaining its importance in the aerospace and power plant industries because of its high strength to weight ratio. The lack of understanding of the tool chip interface for Inconel 718 restricts the prediction of the apparent coefficient of friction and thus the cutting forces, thereby the machining efficiency. In the present study an analytical model has been developed accounting the actual variation of stresses over the rake face. The model focuses on the variation of shear stresses in the sticking region and has been considered to be increasing exponentially with distance from tool tip. The primary shear zone is assumed to be a thin layer with constant thickness and has been modelled using Johnson Cook material model. The shear stresses at the entry and exit of the primary shear zone has been calculated using iterative techniques proposed in the literature. The secondary shear zone has been analyzed dividing the contact length into two distinct regions and each region has been dealt separately. The ratio of real area of contact to the apparent area of contact has been given consideration and dealt with at macroscopic level. Experimental values have been extracted from previous studies on Inconel 718. The predictions of the analytical model was found to be in good agreement with experimental results. The experimental apparent coefficient of friction was obtained as 0.5119 against 0.4733 from the developed model at a velocity of 70 mm/min, depth of cut of 1mm, nose radius of 0.8mm and with negative rake angle (−6°) with CNMG0812 tool. The predicted and the experimental friction coefficient showed a variation of 7.07% – 10% and thus can serve as reliable model for Inconel 718.
Estimation of Effective Thermal Conductivity of Porous Media Utilizing Inverse Heat Transfer Analysis on Cylindrical Configuration
Authors: Fabela Oscar , Patil Sandeep , Chintamani Siddarth , Dennis Brian H.
Published: January 2018

This paper describes the application of inverse analysis to estimate the thermal conductivity of a porous material using temperature measurements at the surfaces. Finite volume analysis code is utilized to solve the steady state axisymmetric heat transfer governing energy equation. The analysis code is coupled with a numerical optimization method and is utilized to predict thermal conductivity constant using the measurements. An experimental setup was developed to test a porous media composed of a mixture of small pellets and air. Semi Analytic Complex Variable Method (SACVM) is used to determine the sensitivity of the predicted material properties on the error in temperature measurements. Temperature obtained from experiments, is used as input to inverse method. The objective function is minimization of least squares error between measured experimental and predicted temperatures. Conjugate Gradient Method (CGM) is used to solve the resulting problem. Accurate sensitivities for the CGM were computed by SACVM. Material properties predicted from this method show close agreement with literature.
Numerical Study of Turbulent Rotating Flow in a Tesla Disc Pump
Authors: Naz Saima , Lockhart Doug , Harwood Peter , Komrakova Alexandra E.
Published: January 2018

The advantages of Tesla’s bladeless turbine over the conventional bladed turbine — such as an easier manufacturing process; low cost; low noise; the ability to operate with different working fluids, including Newtonian and non-Newtonian fluids; and single phase or multi-phase systems [1] — keep the design development of this device a subject of ongoing research. The first design of the Tesla turbine was presented by N. Tesla in 1913 [2]. In the 60s and 70s, a number of research groups built the Tesla device to investigate its performance (power, torque, efficiency) [3]–[6]. At the present time, the efficient design of the Tesla device is still a focus of experimental and numerical research studies [7]–[13].

In this work, the computational fluid dynamics (CFD) simulations are performed to study three-dimensional turbulent compressible flow between the two corotating discs. The wide gap between the discs results in a Reynolds number of 1656, which is calculated based on the disc gap and the rotational speed of the discs. The CO2 gas is used as a working fluid. The simulations are performed using the commercial CFD software (STAR-CCM+, SIEMENS PLM). In this study, we determined the inlet and outlet boundary conditions together with the rotational speed of the discs that make the device work as a pump. The realizable k–ε turbulence model was used. The performance parameters of the pump were assessed by considering the dimensionless flow coefficient and efficiency.
Reissner’s Mixed Variational Theorem for Layer-Wise Refined Beam Models Based on the Unified Formulation
Authors: Carrera Erasmo , García de Miguel Alberto , Pagani Alfonso , Zappino Enrico
Published: January 2018

The present paper proposes the application of the Reissners Mixed Variational Theorem (RMVT) for the accurate stress analysis of general multi-layered beam problems. Laminated materials usually differ from homogeneous materials in that they exhibit much higher transverse shear and transverse normal deformabilities. These characteristics, and others such as the Transverse Anisotropy (TA) and the Interlaminar Continuity of transverse stresses (IC), make Classical Laminated Theories (CLT) inappropriate for the analysis of multi-layered structures. The Carrera Unified Formulation (CUF) sets a framework in which classical-to-refined beam models can be generated by expanding the unknown variables over the cross-sectional domain by means of arbitrary functions. A LW expansion is adopted for both displacements and transverse stresses over the cross-section section domain. In this manner, the ZZ condition is automatically satisfied through the use of independent kinematics for each layer in a LW sense, with no need of introducing ad-hoc ZZ functions.
Combination of Elementary Processes to Form a General Energy System Configuration
Authors: Toffolo A. , Rech S. , Lazzaretto A.
Published: January 2018

The fundamental challenge in the synthesis/design optimization of energy conversion systems is the definition of the system configuration and design parameters. The traditional way to operate in system engineering practice is to follow the previous experience, starting from design solutions that already exist. A more advanced strategy consists in the preliminary identification of a superstructure that should include all the possible solutions to the synthesis/design optimization problem, and in the selection of the system configuration starting from this superstructure through a design parameter optimization. This top-down approach cannot guarantee that all possible configurations could be predicted in advance and that all the configurations derived from the superstructure are really feasible.

To solve the general problem of the synthesis/design of complex energy systems a new bottom-up methodology is proposed, based on the original idea that the fundamental nucleus in the construction of any energy system configuration is the elementary thermodynamic cycle (compression, heat transfer with the hot source, expansion, heat transfer with the cold source). So, any configuration can be built by generating, according to a rigorous set of rules, all the combinations of the elementary thermodynamic cycles operated by different working fluids that can be identified within the system, and selecting the best resulting configuration through an optimization procedure.

In this paper a deep analysis of the major features of the methodology is presented to show, through different examples of applications, how an artificial intelligence is able to generate system configurations of various complexity using preset logical rules without any “ad hoc” expertise.
Template-Based Synthesis of Integrated Carbon Micro- and Nanostructures
Authors: Scheibel Olivia V. , Lanza David , Schrlau Michael G.
Published: January 2018

This work demonstrates the manufacturing process of micro- and nanofluidic devices consisting of independent, aligned carbon pipes with potential applications as micro- and nanoscale dispensing systems, electrodes, and tools with which to study fundamental micro- and nanofluidics. A low-cost, high-throughput chemical vapor deposition (CVD) process was utilized to deposit carbon within novel silica-based templates. This simple template-based manufacturing process allows the carbon devices to be integrated into millimeter scale silica-based templates without micro- or nanoassembly, facilitating commercialization. Furthermore, the carbon-based devices were designed to readily integrate into standard laboratory equipment, promoting broad utilization. Herein, a repeatable methodology for fabricating multifunctional, carbon-based micro- and nanofluidic devices as well as establishing relationships between parameters at each stage of fabrication and the final geometry, including diameter and wall thickness of the carbon structures, of the device is presented.
Thermodynamic Analysis of Ocean Thermal Energy Conversion System With Different Working Fluids
Authors: Li Dashu , Zhang Li , Duan Xili , Tian Xiaosuai
Published: January 2018

A thermodynamic model is developed for ocean thermal energy conversion (OTEC) systems. Considering the narrow temperature range in the evaporator, different refrigerants including R717, R134a and R600 were analyzed and compared under sub-critical state with practical ocean thermal conditions. The results show that larger ocean temperature differences will lead to higher evaporation pressures, and less pumping power requirements for all pumps, i.e., warm sea water pump, cold sea water pump and pumps for the working fluid. The thermal efficiency of different systems and the net power output were found to be closely related to ocean temperature difference, with a positive linear relationship. It was also found that R717 provides the highest thermal efficiency with the least pump power requirement. This working fluid could potentially be used for OTEC system development. This study provides useful insights to the design and equipment selection of OTEC systems.
Uncertainty Propagation for Ring-Based Vibratory MEMS Gyroscopes Under Random Input Angular Speed Fluctuation
Authors: Abedin Nujhat , Asokanthan Samuel F.
Published: January 2018

Uncertainty quantification for ring-type MEMS gyroscopes due to frequency mismatch as well as quality factor is investigated. A suitable two-degree of freedom dynamic model is used to represent the vibratory behavior of a ring-gyroscope considering the second flexural modes. For the purposes of characterizing the vibratory behavior due to uncertain system as well as environmental parameters, steady state portion of transient responses are considered. Monte Carlo simulation method is used for estimating the ensemble mean as well as the standard deviation (measure of variance) of response samples. Employing an optimal sample number predicted via simulations, uncertainty quantification for the response statistics are evaluated via ensemble mean and standard deviations. It is envisaged that the predictions made from the output response statistics and uncertainty quantification analyses of the present study can lead to significant performance improvements in the design of this class of micro-machined ring-type vibratory angular rate sensors.
Continuous Liquid Interface Production of 3D Objects: An Unconventional Technology and its Challenges and Opportunities
Authors: Balli Judah , Kumpaty Subha , Anewenter Vince
Published: January 2018

The purpose of this paper is to understand and research literature on the “continuous liquid interface production (CLIP)” of 3D objects to address the current challenges. This proprietary technology was originally owned by EiPi Systems but is now being developed by Carbon 3D. Unlike conventional rapid prototyping of printing layer-by-layer to print 3D objects, CLIP is achieved with an oxygen-permeable window made of proprietary glass membrane and the ultraviolet image projection plane below it, which allows the continuous liquid interface to produce 3D objects where photo-polymerization is restricted between the window and the polymerizing part. This process eliminates the time requirement in between the layers resulting in the faster production of 3D objects with a resolution less than 100 microns. It is a known factor that the “supports” play a vital role in any liquid based 3D printing techniques and this does not change in CLIP. In addition to the parameters of support structure like shape, size, strength, ease of removability, surface finish after removal of supports etc, CLIP needs to deal with different types of materials. The support structure needs to be designed according to the respective material’s properties. There are two broad categories of the materials available from Carbon 3D, prototyping resins, and engineering resins. While the prototyping resin is used for the cosmetic models and the engineering resins are used for the practical applications. There are 6 types of engineering resins developed for the end user; of these, EPU and CE are more challenging to work with. EPU parts needs more supports and careful handling till the completion of post processing as the material is soft. CE parts are fragile and needs more systematic handling to complete the successful production. Although printing parts of EPU and CE is more time consuming when compared to the normal CLIP process, they are worth for their unmatched industrial applications. None of the existing 3D printing technologies offers this quality. The support structure, orientation and pot life are the influencing parameters for all resins. In this study, it is statistically proven that by optimizing the part orientation with respect to the slicing of each layer and customized supports; parts are built way better than before. The part orientation is optimized by ensuring each layer is supporting the subsequent layer and minimizing the islands. It is noticed that the results are always better by tilting the part 5 to 10 degrees in both X and Y axis in the build setup and this applies for most of the straight geometrical parts. For parts of specific geometry which can create a vacuum while pulling up the part needs to be oriented in a different way or create a re-closable air passage that can prevent the vacuum being created.
An Approach to Tagging Objects of Interest in Oceanic Environments Through the Use of an AUV
Authors: Waltuch Benjamin , Astle Elizabeth , Mirante Eric , Cornwall Brent , McCusker James , Ma Gloria
Published: January 2018

In the field of underwater robotics, Autonomous Underwater Vehicles (AUV) have made many advancements in operating depth, mission endurance, and acoustic range making them the ideal vehicle for surveying and searching for any Object of Interest (OOI) over large areas of water. The downside to this technology is that the operator must wait for the vehicle’s mission to end to determine whether an OOI has been identified. Additionally, if an OOI is identified this object will need to be found again. The solution to this lengthy process is to equip the AUV with a suite of Underwater Locator Beacons (ULB) which can be deployed and anchored next to any positively identified OOI. This way, the operator can be actively listening for the pinging frequency of a deployed ULB where then a secondary Remotely Operated Vehicle (ROV) can be launched to retrieve or further investigate the OOI while the AUV continues its search and tag. This paper presents the design and test of a ULB deployment system that would be implemented into an AUV. An AUV is sensitive to changes in weight, therefore this novel design leverages the concepts of Archimedes Principle by preserving neutral buoyancy pre- and post-deployment of the ULB. Upon deployment, the ULB will be capable of securely anchoring itself in a wide range of seabed environments. To test the design described above, a custom ROV has been fabricated with the sole purpose of transporting the ULB deployment system to operating depth. The paper describes in detail both the test results from the ULB deployment system and a design for implementation into an AUV.
A Relevance Vector Regression Based Uncertainty Quantification Method for Robustness Design
Authors: Chen Chong , Zhan Zhenfei , Yu Huili , Zhao Hui
Published: January 2018

Metamodel based robustness design is commonly used to mitigate the consequences of variability without removing its underlying sources. However, uncertainties introduced by metamodels should be properly addressed before conducting design optimization. In addition, the measurable data uncertainties from physical tests and computer simulations are also unneglectable. Relevance Vector Regression (RVR) is a probability model based on the Bayesian learning framework. It shows potential in estimating the prediction uncertainty. This paper proposes an alternative RVR based robustness design procedure considering the design variables uncertainty, data uncertainty and metamodeling uncertainty. Based on the fundamental theory of RVR, simplified expressions of the response mean and variance is derived for robustness design accounting for three kinds of uncertainties. The formulation of RVR based robustness design is then built. Double loop Monte Carlo sampling is used to solve this optimization problem. An engineering example is used to demonstrate the proposed method and comparative studies are conducted between the proposed method and traditional robustness design.
Hydrogen Production From Renewables: Marine and Hydrokinetic Energy Systems
Authors: Raut Gagee , Goudarzi Navid
Published: January 2018

Hydrogen can be produced from various primary resources by using different processes. The full benefits of hydrogen production can be obtained when it is produced from renewable energy resources. Among these emerging renewable energy resources, marine and hydrokinetic (MHK) energy systems lower variability in the energy production. Also, more than 50% of the total US population resides near water bodies. In this paper, a brief review of renewable energy-based hydrogen production systems is provided, the emission level of both conventional and renewable energy sources for producing the same amount of hydrogen are compared using GREET model, and research needs for further MHK-based hydrogen production systems are discussed. The results showed the significant emission reductions obtained from renewable-based hydrogen production systems. Moreover, the study showed the potential of producing the same amount of hydrogen with less resource quantity of wave energy compared to that from other renewables such as solar energy.
Design of a Wearable 3-DOF Forearm Exoskeleton for Rehabilitation and Assistive Purposes
Authors: Lee Junghee , Ben-Tzvi Pinhas
Published: January 2018

This paper presents the design and analysis of a portable forearm exoskeleton designed for rehabilitation and assistive purposes (FE.RAP). The design uses a direct-drive mechanism to actuate three degrees of freedom (DOFs) of the wrist, including: (1) wrist flexion and extension, (2) wrist radial and ulnar deviation, and (3) forearm supination and pronation. In recent decades, automated at-home recovery therapies have emerged as popular alternatives to hospital-based rehabilitation. Often in the case of lower arm rehabilitation, however, existing exoskeletons are not practical to use as home rehabilitation devices due to being non-transportable, bulky in size, and heavy in weight. In addition, compact sized exoskeletons often lack sufficient DOFs to mirror the natural movements of the hand. This paper proposes a design that addresses the drawbacks of current exoskeletons. The FE.RAP is designed to be portable and lightweight, while maintaining sufficient DOFs to help patients recover the range of motion needed by the wrist and forearm to support activities of daily living (ADL). Along with the design, the paper presents an analysis used to optimize the workspace for each DOF of the system. A kinematic analysis is performed to validate and compare the workspace of the system, as well as the coupling relationship between the DOFs, to that of the human hand and wrist. Finally, the torque required to support most ADLs is determined using static and dynamic analyses.
Adjoint-Based Design Optimization of S-Shaped Intake Geometry
Authors: Askari Rasoul , Shoureshi Peyman , Soltani Mohammad Reza , Khajeh Fard Afshin
Published: January 2018

The S-shaped air intakes are very common shapes due to their ease in the engine-body integration or Radar Cross Section, RCS, specifications especially for fighter aircrafts. The numerical shape optimization of an S-shaped air intake using adjoint method is conducted. The flow of a specified air intake that uses S-duct M2129 is simulated using three dimensional (3D) numerical solution of Reynolds-Averaged Navier-Stokes equation along with k-ω SST turbulence model. The main purpose of this optimization scheme is to maximize the total pressure recovery (TPR). Further, the scheme is developed in such a way that would be applicable in industry thru satisfying specified constraint requirements. The cross sectional areas of the geometry of duct inlet and outlet (known as engine face) remain unchanged. In addition, small shape modification in each optimization step is considered. Finally after nine optimization cycles new S-shaped air intake geometry with higher TPR and lower distortion (DC) is generated, that would achieve higher performance during its operation.
Tacit Knowledge Elicitation Techniques Applied to Complex Manufacturing Processes
Authors: Guerra-Zubiaga David A.
Published: January 2018

Tacit knowledge is one of the main intangible assets in different corporations and an important issue is to explore new tacit knowledge elicitation techniques, being able to identify, categorize, represent, store and reuse this important knowledge type. This paper presents a new tacit knowledge technique called MAKMOSE (Manufacturing tAcit Knowledge MOtion Sequence Elicitation). The new knowledge elicitation technique explores the uses of motion sequence to explore the movements that workers and robots use when performing complex activities. This research provides a knowledge infrastructure representing a tacit knowledge super class to extract valuable experiences. This paper argues that the implementation of MAKMOSE requires exploration and connection of (a) a tacit knowledge infrastructure as a repository, (b) a tacit knowledge life cycle, and (c) implementing the right technology capturing valuable experiences through motion sequence. An important challenge is to demonstrate how new tacit knowledge types can be identified, categorized, stored and reused using motion sequences techniques. This paper presents some research ideas to implement the MAKMOSE in Complex Manufacturing Processes (CMP).
Sensorial Experience Extensions in Learning Environments
Authors: Luís-Ferreira Fernando , Sarraipa João , McManus Gary
Published: January 2018

Emerging technologies are providing a wide range of benefits for people in their different activities. That fact ranges from daily life activities, to business, teaching or simply for recreation. In what concerns to people with special needs there is a wide range of devices and applications that can be of use in addressing those needs and the will to progress in life. Observing in perspective, the support provided by technology can be seen as augmenting our sensorial experience by providing additional information as in the case of virtual reality and augmented reality. The devices provide additional information for what people sense, adding information and enlarging the sensorial experience while mounting additional information. This paper describes a strategy to extend, thru common use technology, the awareness of people with limited sensorial experience, aligning with other emergent technologies widely applicable to different situations while keeping a focus on teaching environments. That includes sensory devices like the Leap Motion device and 3D printed materials, which combined provide new opportunities for blind people to sense and retrieve new information.
On the Dynamics of Complex Network
Authors: Yang Chun-Lin , Suh C. Steve
Published: January 2018

Controlling complex network systems is challenging because network systems are highly coupled by ensembles and behaving with uncertainty. A network is composed by nodes and edges. Edges serve as the connection between nodes to exchange state information and further achieve state consensus. Through edges, the dynamics of individual nodes at the local level intimately affects the network dynamics at the global level. As a following bird can occasionally lose visual contact with the target bird in a flock at any moment, the edge between two nodes in a real world network systems is not necessarily always intact. Contrary to common sense, these real-world networks are usually perfectly stable even when the edges between the nodes are unstable. This suggests that not only nodes are dynamical, edges are dynamical, too. Since the edges between the nodes are changing dynamically, network configuration is also dynamical. Further, edges need be defined and quantified so that the unstable connection behavior can be properly described. The paper explores the concepts of statistical mechanics and statistical entropy to address the particular need. Statistical mechanics describes the behavior of a mechanical system that has uncertain states. Statistical entropy on the other hand defines the distribution of the microstates by probability. Entropy provides a measure of the level of network integrity. With entropy, one can assign desired dynamics to the network to ensure desired network property. This work aims to construct a complex network structure model based on the edge dynamics. Coupled with node self-dynamic and consensus law, a general dynamical network model can be constructed.
On Robustness of Concurrent Learning Adaptive Control to Time-Varying Disturbances and System Uncertainties
Authors: Sarsilmaz S. Burak , Kutay A. Turker , Yucelen Tansel
Published: January 2018

In this paper, we study the robustness characteristics of a recently developed concurrent learning model reference adaptive control approach to time-varying disturbances and system uncertainties. Specifically, the commonly-used constant (or slowly time-varying) assumption on disturbances and system uncertainties for this particular adaptive control approach is replaced with its bounded counterpart with piecewise continuous and bounded derivatives. Based on the Lyapunov’s direct method, we then show that the solutions of the closed-loop system are uniformly ultimately bounded, without requiring a modification term in the adaptive law. Estimates for the ultimate bound and the exponential convergence rate to that ultimate bound are further provided. According to these estimates and illustrative numerical examples, similarities and differences between concurrent learning and one of the well-known robustness modifications in adaptive control, namely σ modification, are explored.
Anisotropic Elasticity Solution of Single Layered Composite Plate Under Self-Equilibrating Cubically Distributed Shear Loading
Authors: Rezaei Amir G. , Tabatabaei Mohseni Amin
Published: January 2018

The anisotropic plane elasticity solution of the stresses throughout a thin, rectangular, laminated composite plate subjected to self-equilibrating cubically distributed shear stress at the two ends of the plate is obtained. The plate is assumed to be a symmetric laminate and hygrothermal effects are not considered. The characteristic decay length under the shear loading is estimated for different cases of isotropic, orthotropic, and anisotropic plate. The work is intended to be presented as an example during a lecture or to be published in new textbook demonstrating the numerical method.
Non-Invasive Water Flow Sensing for Smart Water Heater Controller
Authors: Singer Joe , Jansen Scott , Wang Chenli , Lee Hohyun
Published: January 2018

Water flow rate sensors in residential homes have the capacity to revolutionize energy conservation by providing real time, user specific water usage data to the Internet of Things. Water heaters typically heat water to a constant set-temperature throughout the day. This constant heating contributes to about 18% of total home energy usage, making water heaters an especially effective target for potential energy savings. By harnessing the knowledge of hot water usage and flow rate, machine learning processes can determine an optimized water heating schedule for individual users. However, current methods to determine water flow rate involve either a complicated installation process or use of expensive equipment. The work in this paper proposes an economical, non-invasive package to both detect hot water usage and measure the flow rate, by utilizing three temperature sensors. Processing of the data quantitatively correlates temperature change of the incoming/outgoing water pipes to the water flow rate through the pipes. To accomplish this, the principle of energy conservation was applied using transient temperature measurements taken from the outer surface of both the cold inlet and hot outlet pipes. In the process of formulating energy conservation equations, there exist unknowns which will be determined by different self-testing algorithms. Developing transient and steady state equations for the inlet and outlet pipes allowed for calculations of the flow rate through a water heater to be performed. Specified conservation equations applied to both cold inlet and hot outlet pipes will enhance the accuracy and reliability of the proposed method. For verification, experimental setup was built to verify our model by comparing actual usage and flow rate measurements from a household water heater with the calculated usage and flow rate from the temperature change rate.
Thermal Perception of Skin Using Optical Projections
Authors: Madera Coralis , Hojatmadani Mehdi , Crane Nathan , Reed Kyle
Published: January 2018

The largest human organ is skin, which covers and protects the body from external objects and serves as a medium of interaction with the outside world. Having adequate knowledge about human thermal perception aids in the design of devices that interact with skin and broaden our perspective of the affecting parameters in the perception process. A thermal projector was designed based on an Optima X316 Projector which is capable of creating different thermal patterns on a surface with different intensities by use of visible light waves. Skin temperature was measured via a FLIR A325-SC thermal camera. Using these devices we were able to create thermal patterns and control the rates at which the temperature of human skin is changed. A psychophysical experiment using the setup was used to determine skin thermal sensitivity and threshold. Subjects’ skin was exposed to different thermal projections and their skin was heated at constant rates to certain degrees higher than their skin temperature. As their skin temperature was altered incrementally on each location, they stated whether they could feel the heat on their skin. The experiment showed that there was statistical significance between the rate at which the subjects’ skin was heated and whether the subjects felt a temperature change. Statistical significance was also found between the amount of exposure time prior to the instance subjects felt a change in temperature and the rate at which the skin was exposed.
Experimental Investigation on Heat Transfer Enhancement by Transversal Ribs in Channels
Authors: Buonomo Bernardo , Cirillo Luca , Manca Oronzio , Nardini Sergio
Published: January 2018

In this paper an experimental investigation is carried out on forced convection in channels with the lower ribbed wall heated with a uniform heat flux. The fluid is air. The experimental apparatus is made up of a channel with a transversal rectangular section, a test section, a convergent channel, to reduce the rectangular transversal section in a circular section and a fan between circular tubes. The unheated rectangular channel is long 2.50 m, the transversal rectangular section is 27.8 mm high and 250 mm wide. The test section is 300 mm long and it has the same rectangular transversal section of the unheated channel. In the test section the lower plate is in aluminum and is heated by two electrical resistances whereas the upper plate and the lateral walls are in glass. The experiments are carried out employing a smooth or a ribbed plate. The ribs are transversal and can be squared or triangular. In both cases the ribs are 5.0 mm wide and 5.0 mm high. The rib pitch is 40 mm and along the heated plate there are 7 ribs. Results are obtained in a Reynolds number range from 5000 to 15000 and wall heat flux of 3000 W/m2 and 5000 W/m2. In the experiments two heated wall emissivity values are considered, 0.05 and 0.95. Results are given in terms of wall temperature profiles, air temperature, average Nusselt numbers and pressure drops.
Computer Assisted Design and Structural Topology Optimization of Customized Craniofacial Implants
Authors: Gómez Pérez Carlos A. , Medellín-Castillo Hugo I. , Espinosa-Castañeda Raquel
Published: January 2018

Modern design and manufacturing engineering technologies have greatly improved the way in which modern craniofacial implants are designed and fabricated. However, few efforts have been made in order to optimize their design. While the weight of polymer-based implants (e.g. PMMA implants) may not affect the patient’s comfort, the higher weight of metal-based implants (e.g. titanium implants), could greatly affect the patient’s comfort, causing in some cases nuisances and imbalance problems. Thus, the optimization of the implant becomes relevant in order to guarantee its structural stiffness but with a reduced weight.

In this paper, the design and structural optimization of customized craniofacial implants based on the use of modern engineering technologies is presented. The aim is to introduce an engineering methodology for the design and optimization of customized craniofacial implants. The methodology starts from the patient’s medical images, obtained from a computerized tomography (CT), which are processed to reconstruct the digital 3D model. Next, the geometrical design of the implant is carried out in a computer aided design (CAD) system using the patient’s 3D model. Then, the structural analysis of the implant is performed using the Finite Element Method (FEM) and considering a quasi-static load. The topology optimization of the implant is made using the Solid Isotropic Material Penalization (SIMP) method. Finally, the optimized customized implant is fabricated in an additive manufacturing (AM) system. A case study of a craniofacial implant is presented and the results reveal that the proposed methodology is an effective approach to design and optimize craniofacial implants.
Acoustic Multiple Scattering Using Fast Iterative Techniques
Authors: Amirkulova Feruza A. , Norris Andrew N.
Published: January 2018

Acoustic multiple scattering by an arbitrary configuration of cylinders in an acoustic medium is considered. An iteratively computable Neumann series (NS) expansion technique is employed to expedite the MS solution by means of MS theory. The method works if the spectral radius of the interaction matrix is less than one. The spectral properties of this matrix are investigated for different configurations of cylinders, e.g. rigid cylinders, elastic thin shells, etc.; the validity of solution is shown by modifying the frequency ω, the number of scatterers M, and their separation distance d. Fast computation of Neumann series is investigated using renormalized series expansions.
Energy and GHG Emissions Assessment in a Plastic Injection Process at Machine Component Level: A Case Study of ABS Plastic Part Produced in a Hybrid Injection Molding Machine
Authors: Ávila Javier , Borja Vicente , López-Parra Marcelo , Ramírez-Reivich Alejandro C.
Published: January 2018

In this article a GHG and energy analysis for the plastic injection process of an ABS medium sized injected part carried out in a hybrid injection molding machine is reported. A power consumption process pattern for an ABS medium-size part is defined as well as the energy usage of components, the energy used for the injection process is calculated for the injection cycle and for the process setup. The reported study includes a hybrid machine analysis working under an electric network that relies mainly on thermoelectric energy generation. The GHG emissions assessment was estimated using the 2015 emission factor applied for Mexico. The results provide new experimental data for ABS plastic injected parts in hybrid injection machines.

This paper describes the outcomes of a GHG emissions and energy assessment for an ABS medium-sized injected part carried out in a HIMM at UNAM. The approach followed by the authors in this assessment was aimed at providing information about the energy usage and GHG emissions for the process and the part.

The main contribution of this paper is the insight related to energy usage indicators in the process, the energy usage and the GHG emissions within components. The product used as a case study and the results of its GHG emissions and energy assessment are presented.