bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessment of Elevator Risk and Code Requirements to Address These Hazards
Authors: Bress Thomas , Kennedy Eugenia , Sullivan MariAnne , Guttag Mark 
Published: January 2020

Abstract
The ASME A17.1 Safety Code for Elevators and Escalators establishes safe practices in the design, construction, installation, operation, testing, inspection, and maintenance of elevators. This Code continues to be updated with new regulations to improve safety for elevator riders. The estimated number of elevators in service in the U.S. is approximately 1.1 million.1 Two of the most common injuries for elevator riders are associated with unexpected door closures and trips and falls when entering or leaving an elevator. A recent study reported that door-related incidents accounted for 40% of the total elevator related injuries [1]. This same study reported that another 40% of the total injuries were associated with trips and falls caused by elevator cars that were not level with the landing. These two hazards result in approximately 80% of the elevator-related injuries occurring at the entrance of the elevator. Other recent studies have concluded that older adults [2] and young children [3] are particularly impacted by these elevator-related hazards.
This paper will focus on identifying and analyzing the hazards associated with elevator door closures. In this study, the National Electronic Injury Surveillance System (NEISS) database of the U.S. Consumer Product Safety Commission (CPSC) is reviewed from 1990 to 2017 to better understand the trends associated with door strikes, the affected body part and the age of those involved in the incidents. This study also explores and discusses the safety mechanisms currently available to address these hazards. An examination of updates to the ASME A17.1 Code along with improvements in door reopening technologies will be presented to guide the discussion.
Influence of Active Part Stiffness on Radiated Sound Power Level in Power Transformers
Authors: C. Linhares Cassiano , Costa João S. , Teixeira Ricardo E. R. , Coutinho Cristiano P. , Tavares Sérgio M. O. , Santo João P. A. E. , Mendes Hélder F. G. 
Published: January 2020

Abstract
Power transformers are associated with the radiation of unwanted noise in many circumstances due to its low frequency and relative high power, which reduction and mitigation is imperative. It is known that the main source of this noise are originated by the vibrations induced in the active part, namely the core, primarily due to electromagnetic forces and magnetomechanical effects. On the other hand, the laminated design of the core is indispensable in order to reduce the Foucault currents losses. Thus, in addition to the electrical requirements, the development of an appropriate model of the core dynamic behavior taking into account its segmented structure is urgent, in order to avoid resonances at any of the excitation frequencies. In the current proceeding, the influence of the core equivalent dynamic mechanical properties on a power transformer radiated noise was studied by performing a numerical parametric analysis. It was concluded that the active part stiffness properties, namely the directional component related to the out of lamination plane bending, ruled the vibroacoustic behavior of the transformer for the studied frequency range.
CFD Simulation of an Alfa-Stirling Engine to Study the Geometrical Parameters on the Engine Performance
Authors: Ferreira Ana C. , Teixeira Senhorinha F. C. F. , Oliveira Ricardo F. , Teixeira José C. 
Published: January 2020

Abstract
An alpha-Stirling configuration was modelled using a Computational Fluid Dynamic (CFD), using ANSYS® software. A Stirling engine is an externally heated engine which has the advantage of working with several heat sources with high efficiencies. The working gas flows between compression and expansion spaces by alternate crossing of, a low-temperature heat exchanger (cooler), a regenerator and a high-temperature heat exchanger (heater). Two pistons positioned at a phase angle of 90 degrees were designed and the heater and cooler were placed on the top of the pistons. The motion of the boundary conditions with displacement was defined through a User Defined Function (UDF) routine, providing the motion for the expansion and compression piston, respectively. In order to define the temperature differential between the engine hot and the cold sources, the walls of the heater and cooler were defined as constant temperatures, whereas the remaining are adiabatic. The objective is to study the thermal behavior of the working fluid considering the piston motion between the hot and cold sources and investigate the effect of operating conditions on engine performance. The influence of regenerator matrix porosity, hot and cold temperatures on the engine performance was investigated through predicting the PV diagram of the engine. The CFD simulation of the thermal engine’s performance provided a Stirling engine with 760W of power output. It was verified that the Stirling engine can be optimized when the best design parameters combination are applied, mostly the regenerator porosity and cylinders volume, which variation directly affect the power output.
Design and Start-Up of an Automatic Paint Mixer
Authors: Maradey Lázaro Jessica Gissella , Cáceres Kevin , Garrido Gianina 
Published: January 2020

Abstract
In daily life, is very common to witness scenes in which it is necessary to obtain different ranges of colors in the paintings that are used either with water or oil. This range of colors comes from the fusion and homogenization of primary colors or tones. Frequently, the process of mixing and dosing are carried out by people who, by trial and error, determine the color desired by the user. Then, the quality and precision of the paint is affected and generate customer dissatisfaction, claims, waste, and low productivity.
This article shows the design and start up process of an automatic mixer prototype that doses and mixes paint to create complex color shades by implementing a human-machine interface and a control stage and verification.
Also, the results of this investigation shows the engineering process carried out to obtain a prototype of a functional, automatic, exact mixing machine and a homogenous and quality product that meets the customer’s requirements. Improvements that will can do and future work are included too.
The Evolution of Tridimensional Metrology: The Era of Computer Aided Metrology
Authors: Machado Michael , Silva João , Sousa João , Vale André Filipe Pinto 
Published: January 2020

Abstract
The use of Coordinate Measuring Machine (CMM) provides an accurate and versatile solution for industrial metrology, that is being in use for decades. Although the electromechanical components of these machines have not suffered a great evolution in the last decade, the software used for controlling the CMM have suffer a great development in the last years, making them more user friendly, offering more powerful solutions, such as better CAD support and a better degree of automation, resulting in a faster measuring process. Together with the implementation of new non-contact technologies, like optical sensors for measuring purposes. Overall this resulted in a step further in the functions of a CMM, the measuring process becomes more automatic for either calculations and machine control. The use of new technologies also offers the possibility to work with a bigger amount of data, and virtual data systems turning the process more versatile and able to satisfy the actual demand of the industry, reducing the overall time and price of the inspection process.
Effect of Moisture on the Mechanical Properties of Additively Manufactured PLA, ABS and PLA/SiC Composites
Authors: Kakanuru Padmalatha , Pochiraju Kishore 
Published: January 2020

Abstract
In this study the tensile properties of additively manufactured Polylactic Acid (PLA), Acrylonitrile Butadiene Styrene (ABS) and Silicon Carbide (SiC) particulate filled PLA composites were assessed after aging for 4.5 months at 50°C in distilled water. The maximum moisture gain in PLA was about 16% by weight, and ABS gained 0.65%. In PLA/SiC composites, the weight gain due to moisture absorption was inversely proportional to the weight percentage of SiC loading. The PLA specimens degraded completely during aging without measurable residual strength. While the addition of SiC to PLA increased the room temperature tensile strength at lower volume fractions of SiC, the degradation of aged strength was similar to that of the pure PLA. The PLA/SiC composites had no measurable strength after aging. The ABS specimens retained their strength and failure strain after aging.
Numerical Investigation on a Flat - Tube Heat Exchanger in Metal Foam
Authors: Buonomo Bernardo , Cascetta Furio , di Pasqua Anna , Ginetti Piera , Manca Oronzio 
Published: January 2020

Abstract
A numerical analysis on a heat exchanger in aluminum foam with flat tubes is accomplished. The flow equations in two-dimensional steady state regime are written considering the local volume averaging process. The foam considered as an open porous medium is modelled in local thermal non-equilibrium (LTNE) under the Darcy-Brinkman-Forchheimer hypothesis. The metal foam behaviors such as porosity and pore density (pore per inch, PPI) are assigned equal to 0.9353 and 20. Several configurations of the flat tube with different dimensions are considered. A fixed surface temperature on the flat tube is selected and several mass flow rates are examined. The numerical solutions are carried out by means of the Ansys-FLUENT code Pressure drop in the system and average heat transfer coefficient on the flat tube external surfaces are presented. Moreover, pressure and temperature fields are reported for the different configurations. At the end, a comparison with the same scheme characterized by a circular tube is accomplished.
Effect of Uvula Length on Airflow and Pressure Oscillation in a Human Pharynx Model
Authors: Zhao Xuanming , Wang Junshi , Han Pan , Xi Jinxiang , Dong Haibo 
Published: January 2020

Abstract
Unsteady uvula motions and the resultant pressure oscillations within the pharyngeal airway are critical for the pathology of snoring and sleeping apnea. In this paper, an immersed-boundary-method based direct numerical simulation flow solver was adopted to simulate the unsteady flows in an anatomically accurate pharynx model reconstructed from human magnetic resonance images (MRI) with prescribed uvula oscillation and airway obstruction. In order to study the influence of uvula length on the aerodynamics of pharyngeal airflow, simulations were conducted using various uvula models with scaled uvula lengths at 25%, 50%, 75%, and 100% of the original length, respectively. Analyses of vortex dynamics, pressure oscillations, and the aerodynamic force of uvula were conducted. It was found the length of uvula had significant impacts on vortex development as well as aerodynamic pressure/force. Shorter uvula induced weaker pressure oscillations and fewer vortices in the airway. Further fast Fourier transform analysis of pressures from different pressure probes showed higher-order harmonic waves other than the base frequency of uvula motion. This study is expected to bring understanding of snoring and sleep apnea and provide guidance for surgery.
A Capacity Planning Model for Microgrids in Rural India
Authors: Bandyopadhyay Arkasama , Ramirez-Meyers Katrina , Wikramanayake Enakshi D. , Leibowicz Benjamin D. , Webber Michael E. , Bahadur Vaibhav 
Published: January 2020

Abstract
In this study, we develop a load estimation method and an optimization tool for community-driven planning of rural electricity systems which aims to encourage stakeholder involvement in planning processes and reinforce the sustainability of small-scale electrification projects. Electricity demand is estimated through the bottom-up construction of load profiles based on devices used in three common rural end-use sectors. A cost minimization model is then implemented to determine the least-cost capacity composition that can be installed based on the load profile and energy availability. The energy sources modeled are small-scale wind, hydro, solar (photovoltaic), diesel, and battery. In the base case, which includes the three sectors equally, most of the optimal capacity (77%) is provided by renewable energy at an average levelized cost of electricity (LCOE) of $0.05/kWh for a notional village with 500 houses. The base case results are compared to the results when each sector is respectively favored. The results show that backup dispatchable generation and batteries can both be solutions to intermittent renewables, and the choice between the two appears to depend on the load shape. We also find that the base case results are not very sensitive to the CO2 tax, suggesting that not only are renewables cost-competitive with or without the tax, but they also benefit economically from coupling with cheap fossil fuel generators.
Application of Extended Kalman Filter to Dynamic Tracking Problem in R-LATs
Authors: Su Wenjun , Jia Kang , Hong Jun , Liu Zhigang 
Published: January 2020

Abstract
Many applications requiring dynamic tracking have been needed in large-scale. As a novel distributed measurement system, RLATs is presented and the key techniques are shown in detail. Because of the intrinsical drawback of distributed measurement systems, the Extend Kalman Filter approach is introduced to eliminate the tracking error and improve the tracking accuracy. State space model of RLATs are formulated, and an analytical expression for the linearized measurement function is derived. Comparison with the method of LS simulated data which presented a considerable improvement and stability in accuracy and the proposed EKF method while target’s moving speed is less than 100 mm/s.
An Enhanced Hybrid Model for Teaching Mechanics of Structures Courses
Authors: Rodríguez-Paz Miguel X. , González-Mendivil Jorge A. , Zárate-García J. Asuncion , Zamora-Hernandez Israel 
Published: January 2020

Abstract
In this paper we show results on how a proposed enhanced model for the teaching of Applied Mechanics Courses, particularly Mechanics of Structures courses, facilitates the motivation of students and lecturers resulting in an overall improvement of student satisfaction and their grades. The use and design of new spaces for teaching of such engineering courses that make use of collaborative activities and the solution of specific challenges are also presented. The enhanced model presented in this paper includes the use of new technologies in teaching, namely offline video repositories, new facilities for the teaching that are no longer the classic lecture room and the combination of traditional techniques such as tutorials. The paper also shows how they are incorporated into the proposed teaching model resulting in an hybrid model. The model is applied to a number of courses at the undergraduate level taken by second-year Architecture and Civil Engineering students. The results show that all the factors mentioned above are well received by students and improve the overall satisfaction that students show for the selected courses and above all, the improvement in the passing rates for the courses. The conclusions and results presented in this paper could help in the design of new courses and spaces for teaching of courses that are considered difficult by students, such as Applied Mechanics Courses.
Study of the Effect of Carbon Nano-Tube Waviness and Volume Fraction on the Damping Property of a Polymer Composite
Authors: Kulkarni Shank S. , Tabarraei Alireza , Shukla Satyam 
Published: January 2020

Abstract
Composites including carbon nanotubes are of great value due to their thermal, electrical and mechanical properties. They have a wide range of uses in the structural and electrical/electronic industry due to their high strength to weight ratio and high conductivity. Here we study the effect of carbon nanotube waviness and volume fraction on the damping properties of a polymer composite. The analysis is done using the finite element method over a representative volume element which consists of carbon nanotubes as inclusions dispersed in a viscoelastic matrix. The carbon nanotubes are of similar density as the matrix but have a higher modulus of elasticity. This study analyzes the effect of change in volume fraction and waviness of the nanotubes on the damping properties when subjected to a range of vibration frequencies under mixed boundary conditions. This study also analyzes the effect of two different loading direction while keeping the boundary conditions the same. It has been observed that the damping capacity of the composite is greatly dependent on applied loading frequency. Also, the damping capacity of composite decreases significantly as the volume fraction of nanotubes increases. The waviness of nanotubes also has a similar effect on damping property of composite as of volume fraction of nanotubes.
Experimental Investigation of PolyJet 3D Printing Process: Effects of Finish Type and Material Color on Color Appearance
Authors: Wei Xingjian , Zeng Li , Pei Zhijian 
Published: January 2020

Abstract
The Stratasys J750 PolyJet printer is capable of printing full-color parts. However, little information is currently available about the effects of finish type and material color on color appearance of parts printed by the PolyJet process. In this study, the effects of finish type and material color on color appearance of PolyJet printed parts are investigated; two finish types (glossy and matte) and four material colors (cyan, magenta, yellow, and black) are considered. The results suggest that the main effects of finish type and its interactions with material color are significant. Especially, the effects of finish type when material color is black are more significant among the material colors. These results would be valuable to users of the full-color PolyJet 3D printer.
Dependence of Measuring Instrument Eccentricity and Tilt Error on the Four Mathematical Methods of Circularity Form Errors
Authors: Ghosh Suhash , Sahay Chittaranjan , Malempati Poorna Pruthvi Chandra , Singh Swetabh 
Published: January 2020

Abstract
In precision machining of cylindrical parts, the measurement and evaluation of circularity is an indispensable component to quantify form tolerance. Of all the methods of measuring these form errors, the most precise is the one with accurate spindle/turntable type measuring instrument. On the instrument, the component is rotated on a highly accurate spindle which provides an imaginary circular datum. The workpiece axis is aligned with the axis of the spindle by means of a centering and tilt adjustment leveling table. Based on reference circles, this paper focuses on the four modeling methods of roundness, namely, (1) Least Squares Circle (LSC), (2) Maximum Inscribed Circle (MIC), (3) Minimum Circumscribed Circle (MCC) and (4) Minimum Zone or Minimum Radial Separation (MRS) Circles. These methods have been explained in author’s previous article in the context of their implications on design applications, advantages and disadvantages. In this article, the authors have investigated the dependence of these mathematical methods based circularity form error on instrument’s centering error (also known as eccentricity) and tilt error. Some intriguing results were observed for the highly nonlinear relationship of machine’s centering/tilt error with circularity results outside its useful linear region (50–600 μin for this specific machine used in this investigation). Further, the linear and nonlinear relationship was mapped within the effective boundaries of eccentricity settings to investigate the best and worst methods of circularity measurements that are susceptible to instrument errors. Very high and low machine eccentricity settings in its nonlinear regions were not accurately compensated by the machine in circularity results processing. In this study, a master part with different circular and cylindrical features was studied with varying levels of preset instrument eccentricity and tilt errors. Off the four methods, MRS reported the least circularity results. The other three methods didn’t provide any predictable trend. Circularity results were observed to differ up to 35% within these four methods. However, in this preliminary investigation, this maximum difference doesn’t appear to follow any predictable trend with varying machine eccentricities. This article also reinforces the significance of these parameters, and the way they should be understood and be incorporated into undergraduate and graduate engineering curriculum, and be taught as an improved toolkit to the aspiring engineers.
Transient Thermal Performance and Ground Temperature Variation for a Heat Pump System Using High Thermal Conductivity Energy Piles
Authors: Mwesigye Aggrey , Nguyen Hiep V. , Daneshazarian Reza , Bayomy Ayman , Atefrad Pedram , Dworkin Seth B. 
Published: January 2020

Abstract
To reduce the cost of ground source heat pump systems (GSHPs), the use of foundation piles as ground heat exchangers is a promising alternative. Unlike conventional systems, no additional drilling costs are incurred, greatly reducing the initial cost. In this study, the influence of varying pile sizes and grout backfill material thermal conductivity on the performance of a foundation pile ground heat exchanger is numerically modelled and optimized. Piles with diameters between 0.15 m and 2 m with a depth of 30 m, and backfill material with thermal conductivities of 2.0 W/mK and 3.6 W/mK have been considered. The study was accomplished using a thoroughly validated finite element model that determines the ground temperature distribution and energy transfer rates accurately. First, steady state performance was determined for different inlet temperatures in the range 0 to 45°C, then, using an actual heating and cooling load profile for a balanced building, the performance of the heat pump system was determined over a 4-year period. From the study, only the 2000 mm pile gives the most stable performance for the load used with COPs between 3.1 and 6.2 for the 2.0 W/mK backfill material. Smaller piles are shown to be unsuitable for the load, leading to malfunctioning of the heat pump in the cooling season. For a 1200 mm pile, the COP is in the range 0–6.0, but does not handle the cooling loads in the summer. Improving the thermal conductivity from 2.0 W/mK to 3.6 W/mK for the 1200 mm significantly improves the cooling performance and helps avoid failure of the heat pump. The cooling COP increases to about 2.0 from below zero values when the thermal conductivity is 2.0 W/mK for the 1200 mm pile.
Atomistic Investigation on Mechanical Properties of Sn-Ag-Cu Based Nanocrystalline Solder Material
Authors: Motalab Mohammad , Subad Rafsan A. S. I. , Ahmed Ayesha , Bose Pritom , Paul Ratul , Suhling Jeffrey C. 
Published: January 2020

Abstract
In order to develop light weight electrical components, the nano-sized lead free solders have been identified as potential materials to provide better mechanical properties as compared to the conventional solders. Sn–Ag–Cu (SAC) solders have been widely acknowledged as one of the most promising replacements for Sn-Pb solders. In our previous work, mechanical properties of single crystal SAC solder material were investigated through atomistic simulation studies. In this work, the mechanical properties of nanocrystalline SAC305 (nc-SAC305) (96.5Sn-3.0Ag-0.5Cu) solder have been investigated through molecular dynamics (MD) simulations. A set of modified embedded atom method (MEAM) potential parameters have been proposed for nc-SAC solder. Impact of grain size, strain rate and temperature on the uniaxial tensile properties have been studied. The results have revealed an inverse Hall-Petch relationship in the nc-SAC305 material, and grain boundary decohesion is observed as the dominating failure mechanism. The results also suggest that the ultimate tensile strength of SAC305 significantly increases with increasing strain rate. Moreover, increased ductility and decreased ultimate tensile strength are observed at elevated temperatures.