bluuebunny/crossref_metadata_2025 huggingface dataset:
A Simulation Study on Finned Cooling Channels in Injection Mold
Authors: Muszynski Pawel
Published: January 2018

This article presents the proposal of using new, finned cooling channels in injection molds, in order to improve the efficiency of a cooling process. Furthermore, the results of numerical modeling heat transfer in injection mold are presented and analyzed to justify the use of channels with proposed shapes. The need to explore this topic results from many problems associated with the moldings cooling process in injection molding cycle. The main problem during the cooling stage is to ensure the uniform and balanced heat removal from cooled material and proper dynamic of the entire process, as to avoid molding’s defects. The dynamics of the cooling process that is incorrectly selected can cause following defects in moldings: joining lines, streaks, the diesel effect, sink marks, differential shrinkage, excessive internal stresses, product warpage and others. The main aim of this article is to compare the effectiveness of heat transfer between cavity inserts with smooth cooling channels and finned cooling channels. The series of numerical simulations, using FEM, were performed to establish the best configuration of fins in respect of shape which guarantees the most effective heat transfer. The analysis was carried out for channels of various fin geometries (their different numbers and height). The conducted simulations helped to determine the efficiency rates of heat exchange and Darcy friction factors for the analyzed scenarios. The investigation results showed that using new solution allowed the increase in the effectiveness of the cooling process in injection molds.
Atomistic Simulation of Mixed Mode Fracture in Vitreous Silica
Authors: Lahkar Simanta , Ghosal Subhas , Singh Gaurav
Published: January 2018

In this work, molecular dynamics simulations have been used to study the brittle fracture behaviour of vitreous silica in mixed mode loading at room temperature. An implementation of the BKS potential with the coulombic term was used along with Lennard-Jones modification to model initial cristobalite. Ewald summation was used to obtain long-range coulombic contribution to the total potential energy of the system. A recipe (Huff et. al., Journal of Non-Crystalline Solids, 253, 133–142, 1999) was used to obtain the vitreous silica using a combination of different molecular dynamics runs which were done initially as NVT ensemble and at the end as NPT ensemble. Uniaxial tensile tests for uncracked specimen was carried out to validate the microscopic and macroscopic properties with that in the literature. Further, slit center cracks of different orientations were introduced in the vitreous silica and subjected to mixed mode loading by moving the boundaries slowly. Studies of mechanical behaviour were made to derive the variation of fracture stress and stiffness with the mode-mixity in amorphous solids.
Cyber Integrated Metrology, Learning and Evaluation System: An Approach Towards Smart Factories
Authors: Helgoson Martin , Westlin Pontus , Kalhori Vahid
Published: January 2018

Manufacturing processes has seen constant change in the last decades to remain a central element of global wealth and development. Despite large efforts to increase efficiency, still significant sources of waste during manufacturing execution exist. These are mainly based on poor manufacturability, inefficient processes and low machine utilization.

The digital transformation towards “smart factories” will however enable development of new types of methods and technologies that will support advanced automation, resource efficiency and further improvements towards Lean Manufacturing processes.

This paper presents an approach for integrated evaluation of errors introduced from process planning to machined component. Critical parameters, influencing and interrelated factors, nominal value deviations from successive process steps and real-time machining are analyzed in one common cyber-physical model. This will in turn enable analyses of root-causes and serve as basis for process feedback, quality assurance and machine learning.

The focus in this paper is to describe the architecture of the Cyber Integrated Metrology, Learning and Evaluation System (CIMLES) approach and results from proof of concept demonstrators for 3- and 5-axis machining, developed in order to evaluate and verify various subsystems of the approach.
Truss Optimization With Random Piecewise Linear Beams
Authors: Carroll Devin , Yim Mark
Published: January 2018

Disaster zones are often full of “found” material which are debris that can be recycled and used to build practical structures. In this paper, the question of how to build truss structures from these members of arbitrary geometry is introduced and a solution presented. Assuming a set of “found” truss members is provided and that each beam is made from a set of piecewise lines, they are approximated as straight. This is done to simplify the optimization process. A general linear search is then used to investigate possible structures until an optimal structure, with respect to weight and similarity to a desired construction, is found.
Modular Design of Data-Driven Analytics Models in Smart-Product Development
Authors: Li Yunpeng , Roy Utpal , Saltz Jeffrey S.
Published: January 2018

Data-driven analytics models have been built as critical components of a smart product to enable product autonomy and intelligence. Due in part to the dynamic nature of the machine-learning algorithms used in data-driven analytics models, the configuration of a smart product is frequently refined, often in a real-time context. Hence, a smart product requires a continuous evolution of its architecture.

This paper proposes a systematic method to facilitate the modularization of an analytics model architecture, so that a modular smart-product architecture can be achieved. Productizing an analytics model transforms conventional task-oriented data analytics activities into a data product development process. Issues related to the standardization of analytics models, the modular design approaches, the modularity quantification, and their impacts on the overall smart product design, are discussed. The proposed method is applied to an unmanned aircraft system (UAS) design so that a modular UAS architecture can be configured for various mission applications.
Free Convection Heat Transfer From Sierpinski Carpet Fractal Fins of Varying Size
Authors: Calamas David , Dannelley Daniel , Shaffer Jennifer , Soloiu Valentin
Published: January 2018

This works experimentally investigates the thermal performance of extended surfaces inspired by the first four fractal iterations of the Sierpinski carpet fractal pattern in a free convection environment. Fractal fins inspired by the Sierpinski carpet fractal pattern can result in an increase in surface area for convective heat transfer coupled with a simultaneous decrease in mass and are thus desirable in aerospace applications. The thermal performance of the Sierpinski carpet fractal fins was quantified based on fin efficiency, fin effectiveness, and perforated fin effectiveness. When compared with a solid rectangular fin, without perforations, and of an equal base area and package volume a fin inspired by the fourth iteration of the Sierpinski carpet fractal pattern was found to be more effective at dissipating heat by convection. The impact of fin size on the thermal performance of the fractal fins was investigated for a range of power inputs applied at the base (2.5 W, 5 W, and 10 W). A 5.08 cm × 5.08 cm (2 in × 2 in × 1/16 in) fractal fin inspired by the fourth iteration of the Sierpinski carpet fractal was found to have a convective effectiveness, convective efficiency, and convective effectiveness per unit mass, 10.91% more, 10.31% less, and 77.65% more, than a traditional solid (non-perforated) rectangular fin of equal height, width, and thickness. Similarly, a 10.16 cm × 10.16 cm (4 in × 4 in × 1/8 in) fin inspired by the fourth fractal iteration was found to have a convective effectiveness, convective efficiency, and convective effectiveness per unit mass, 3.97% more, 15.91% less, and 66.54% more, than a traditional solid (non-perforated) rectangular fin of equal height, width, and thickness. Thus, the thermal performance of the fractal fins increased as the size of the fins decreased. Regardless of size, the contribution of thermal radiation was significant (often greater than 50%) and should not be neglected. In general, for a fin with a uniform cross-section, intersurface thermal radiation accounts for a significant percentage of thermal radiation heat transfer, particularly as the size of the perforations decreases.
Mechanical Assessment of Anterior Cervical Decompression and Fusion Using a Zero-Profile Construct: A Computational Study
Authors: Uddin Ahsan , Alshareef Mohammed , Ferdous Jahid , Lowe Stephen , Shazly Tarek
Published: January 2018

Anterior cervical decompression and fusion (ACDF) is a surgical procedure typically utilized in cervical spine disc herniation to alleviate spinal cord compression. There have been several implants used in ACDF surgeries [6,11]. Common implants include standalone cages that insert in the intervertebral space (zero-profile) and cages with an anterior cervical plate and screws that connects the adjacent vertebral bodies. The anterior cervical plate and screw placement has been the preferred method due to increase in fusion rate, reduced graft subsidence, and overall improved lordotic alignment [1]. Multiple studies have shown that standalone cages like the zero-profile result in higher incidence of failure and cage subsidence [16, 17, 18, 10, 19, 20]. This study aims to evaluate the mechanical stress induced by a zero-profile construct throughout the spine as a means to understand device risk and predict mechanical failure.

There are specific levels within the cervical spine that fail more often if adjacent levels are fused. When the level above the construct fails, it tends to be a process of subsidence and collapses of the above vertebral body onto the construct. This can be due to poor bone quality, or failure of bone growth to induce bony fusion between the two levels adjacent to the construct. Conversely, levels below the construct do not subside, but have an increased chance for disc herniation, requiring re-operation and extension of the fusion. The interaction of these levels and implanted cages remains poorly understood from a mechanical standpoint, and even less so in instances of multilevel ACDF [2].

Our computational model geometry included a zero-profile construct placed at a single level, followed by the application of physiological loading to the vertebral column. Parametric studies that probe various load magnitudes predict that resultant stress fields are concentrated at the level above the construct. High stresses immediately above the construct suggest an increased likelihood for subsidence in comparison to the levels below, which is in concert with clinical findings. Interestingly, the levels below the contrast experienced minimal stress shielding in comparison to referent normal simulations. Additional studies examined multidirectional forces that mimic flexion and extension of the cervical spine, with qualitatively similar findings of elevated stress above the construct. This model enables mechanical assessment of cervical spine instrumentation and provides a framework for understanding multilevel ACDF and predicting the performance of new cages/approaches to stabilize the spine.
Capillary Force Guided Nanomanufacturing of Composite Materials for Advanced Battery Applications
Authors: Pint Cary L.
Published: January 2018

This paper introduces the use of capillary thermodynamics as a powerful nanomanufacturing tool, and its specific application to infiltrate sulfur into 3-D nanostructured electrodes for advanced lithium-sulfur and/or sodium-sulfur battery development. The capillary effect specifically targets nucleation from the equilibrium vapor pressure of bulk sulfur (gas phase) onto nanoscale surfaces (liquid phase). This leads to condensates that nucleate and grow uniformly over the surface leading to self-limited and conformal composite materials moderated by the chemical potential driving force between the nanoscale nuclei and the bulk sulfur. Our studies show highly consistent and repeatable sulfur loading exceeding 80 wt.% sulfur, fast kinetics that can lead to full infiltration in ∼ 10 minutes, and synergy with pre-formed carbon materials including carbon nanotube arrays, carbon nanotube foams and sponges, and microporous carbons with pore sizes ∼ 0.5 nm. This overcomes challenges of scaling to high areal capacity in lithium-sulfur and sodium-sulfur batteries, and our results emphasize the highest reported areal capacities for solid-processed cathodes to date (> 19 mAh/cm2). This paves the route to batteries with energy density > 500 Wh/kg with reliable manufacturing processes that simultaneously sustain low cost and high throughput.
A Preliminary Study on 3D Printed Smart Insoles With Stretchable Piezoresistive Sensors for Plantar Pressure Monitoring
Authors: Emon Md Omar Faruk , Choi Jae-Won
Published: January 2018

In this report, we present a 3D printed insole which has multiple soft pressure sensors inserted in it to detect the force on the sole including heel, midfoot, and forefoot as well as timing and location of the strike while walking. The insole was 3D printed using a soft and flexible material having multiple open channels on it to attach sensors. Flexible and stretchable piezoresistive sensors were fabricated via screen printing and molding processes. The multi-layer sensor comprises an ionic liquid (IL) based piezoresistive layer sandwiched between two multi-walled carbon nanotube (MWCNT) based stretchable electrodes and finally, top and bottom insulation layers. The sensor was constructed using 3D printable photopolymer as 3D printing is our target manufacturing technique to build the entire structure including insole. The sensor embedded insole was evaluated for different foot landing conditions such as heel strike, midfoot strike, and forefoot strike. Experimental results showed that the developed insole could indicate the amount of force on insole when foot hits ground, with timing and location of the strike.
Nonlinear Dynamics and Control of Rotors Operating Within the Clearance Gaps of Magnetic Bearing Systems
Authors: Keogh Patrick S. , Lusty Chris , Bailey Nicola Y.
Published: January 2018

Under normal operation a rotor spinning within an active magnetic bearing system will be levitated and hence rotor-stator contact conditions do not exist. In such a case, external disturbances and inherent unbalance will cause rotor responses that are maintained by the magnetic bearing control system to be within the clearance gap. However, magnetic bearings have limited dynamic load capacity due to magnetic material field saturation. Hence large external disturbances may be sufficient to cause the clearance gap to become closed and result in rotorstator contact. A touchdown bearing is usually incorporated as a sacrificial stator component to protect the expensive rotor, magnetic bearing and sensor components. Once contact has been made, rotor dynamic conditions may ensue resulting in persistent rotor bouncing or rubbing limit cycle responses. Prolonged exposure to these severe dynamics will cause touchdown bearing degradation and require regular replacement. A clear aim is therefore to restore contact-free levitation through available control capability in an efficient manner. This paper provides an analysis to gain an understanding of the uncontrolled rotor/touchdown contact dynamics. These will then be used to guide the control options that are available to restore contact-free levitation. The use of magnetic bearing control is appropriate if the required control forces are within saturation limits. It is also possible to actuate touchdown bearings and destabilize persistent rotor dynamic contact conditions. For example, piezo-based actuation offers larger control forces than those from magnetic bearing systems.
Experimental and Computational Comparison Between Widnall and E423 Shroud Designs for an Axial Wind Turbine
Authors: Marie Hazel , Jarullah Abbas
Published: January 2018

For at least 3000 years before using wind to generate electricity, wind power had been used on land, mainly for grinding grain or pumping water, and at sea, as power for sailing ships. In relatively recent times, the usage of wind turbines to generate electricity has gained momentum. This is partially due to environmental threats from fossil fuel usage. It has become essential to look for energy sources which are renewable and clean to eliminate or reduce the environmental pollution and lower economic costs. However, using wind turbines in traditionally low wind speed areas has proved to be economically prohibitive. To address this issue, ducted or shrouded wind turbines have been studied and developed throughout the twentieth century. When the shroud is designed optimally, a lift force is generated by the flow through the shroud, and the effect of this lift is to increase the mass flow rate through the rotor plane. This study compared two shroud designs; the established Widnall design and a new design shaped by revolving airfoil E423 (high lift force) about a center-line. Numerical and experimental simulations were conducted at lower wind speeds in order to compare the augmentation velocity factors of each design. The effect of various design parameters on the shroud performance, namely drag force, area ratio, angle of attack for the shrouds, cost effect, and shroud geometric influences were considered. The computational fluid dynamic techniques were conducted using commercially available software. Experimental investigations on a micro-shroud included measurement of the velocity distribution inside the shroud and determination of the extracted power in these shrouds by placing a small turbine at the throat region. A low speed wind tunnel was used for the experiments. Both of the shrouds (Widnall and E423) were modeled using readily available databases for each airfoil. The models were then manufactured with a 3D printer using PLA plastic material. Results obtained from numerical simulations showed that the velocity factor increased linearly with increasing area ratio and shroud length for both shrouds. Experimental investigations on an empty micro-shroud showed good agreement with the computational fluid dynamics velocity distribution and augmentation velocity factor at the throat area. Power output from the micro-turbine was experimentally determined for a no shroud system, a Widnall shroud system, and an E423 shroud system. Both shroud systems improved the micro-turbine performance. In all instances investigated, the E423 shroud outperformed the Widnall shroud.
Development of a Methodology for Paint Dust Waste Energetic Valorization Through RDF Production
Authors: Vilarinho Cândida , Ribeiro André , Carvalho Joana , Araújo Jorge , Ferreira Manuel Eduardo , Teixeira José
Published: January 2018

Industrial activity of aluminum surface coating, namely by electrostatic painting with a polyester powder based resin, generates a significant array of wastes. Among these wastes, paint dust is classified as 08 01 12 on the European List of Wastes. As consequence of the inexistence of adequate treatment routes for its correct management, this waste is currently landfilled, without any energy and / or material recovery. Therefore, the development of proper waste management technologies in line with the environmental policies is imperative in order to improve the industrial competitiveness and to preserve the natural resources.

In the present work, RDFs (Refused Derived Fuel) were produced, as pellets, for energetic valorization. These experimental RDF pellets were manufactured by mixing the industrial paint dust with sawdust (1.5 and 3%) and with paperboard (1.5%). They were subsequently tested on a purpose built experimental boiler and the combustion efficiency was assessed in terms of gaseous emissions and chemical composition of the bottom and fly ashes.

The paint dust waste was delivered by a local surface treatment company and characterized concerning chemical, physical and eco toxicological properties, proving to be rich in Carbon (50.2%) and Hydrogen (4.73%). The obtained RDFs were characterized for mechanical durability, elemental and chemical analysis, bulk density and lower heating value. Results show that the utmost lower heating value (19670 kJ/kg) was obtained for the maximum incorporation content of paint dust waste tested (3%).

Combustion trials were carried out at a fuel flow rate between 2 and 3 kg/h. The results showed that the incorporation of paint dust waste resulted in a decrease of the thermal efficiency which suggests that the air fuel ratio was not properly adjusted to the varying heat value of the fuel blend. For all the tests, the mass flow rate and the quality of the gaseous emissions were evaluated for the most relevant pollutants such as particles, SO2, TOC, CO and NOx. All parameters, except for particles in one single case, comply with strict environmental limits applicable. Samples of ashes have also been collected and their chemical composition correlated with the fusibility behavior. The results show that such levels of incorporation could be an effective process for paint dust waste management from both the environmental and energetic points of view.
Use of Supercritical CO2 Heated With Geothermal Energy for Power Production Through Direct Expansion and Heat Supply to an ORC Cycle
Authors: Ruiz-Casanova Eduardo , Soto-Sánchez Ana Laura , Rubio-Maya Carlos , Romero Carlos E. , Levy Edward K.
Published: January 2018

Sustainable energy supply and environmental impact caused by burning of fossil fuels are two of the major worldwide concerns. Regarding sustainable energy supply, several non-conventional alternatives and technologies are currently under study to be implemented from short- to mid-term. On the other hand, CO2 capture and sequestration (CCS) has been considered as a means for controlling anthropogenic greenhouse gas. Based on these considerations, CCS along with non-conventional heat mining and use of geothermal energy is one of the mid-term concepts that is subject to an in-depth research. One of those research lines involves injection of supercritical carbon dioxide (sCO2) in a naturally high-permeability hydrothermal reservoir in order to mine geothermal energy for subsequent power production. This requires to understand widely the behavior of sCO2 inside the geothermal reservoir, as well as to study feasible options for sustainable power production using sCO2 as a working fluid. The present work refers to CO2 captured from a fossil fuel plant that is compressed and injected into a geothermal reservoir forming a geothermal plume for extracting geothermal energy for power production. Assuming that hot sCO2 is available for power production, a power system is proposed and analyzed using a process simulation software. The plant configuration allows sCO2 to circulate through a direct expansion turbine for production of electricity, then sCO2 at the outlet of the turbine passes through a heat exchanger to provide heat to an organic Rankine cycle for additional power production. Supercritical CO2 leaving the heat exchanger is compressed and reinjected back into the geothermal reservoir for further heat mining. Based on a pre-selection stage, Isobutane, R245fa and CO2 were selected as working fluids to analyze the performance of these working fluids on the entire power system. The results show that the combined system makes use of geothermal heat mined by sCO2 more effectively than a pure ORC, increasing the overall energy efficiency of the system.
Simulation and Experimental Study of NiTi Double Helix Stents for Human Coronary Arteries
Authors: Potnuru Akshay
Published: January 2018

Despite new improvements in coronary artery stents, there is still great concern over the failure and lifecycle of stents in patients. In this work, we explore different models of existing stents fabricated using shape memory alloy and analyze them from the mechanical failure point of view and finally propose a novel double helix stent model for coronary arteries inspired from the structure of DNA. We conducted several simulations of the model under different conditions. The experiments are conducted using hyper elastic silicone rubber mimicking the human coronary arteries and the sample stent model made of super elastic NiTi shape memory material.
An Integrated Framework for the Outcome-Based Assessment and Accreditation Process: A Canadian Experience
Authors: Ismail Mohamed
Published: January 2018

In this paper, an integrated system for outcome-based assessment and continuous improvement is presented. The system is designed and implemented as a suite of three integrated Apps: An Excel-App for creating Auto Grading Sheets (AGSs); a Web-App for building assessment trees, updating server database(s), uploading associated documents, and conducting surveys; and a Win-App for program-wide and faculty-wide OBA data compilation, performance analysis, and data-informed continuous improvement. The proposed system adopts a bottom-up approach for building assessment trees that define the structure and the smart logic embedded in AGSs. Some course assessment activities, possibly all, are mapped to graduate attributes, more precisely indicators, and course learning outcomes. The proposed system analyzes the collected data from three different views: 1) Categorical Analysis view (CAs), 2) Learning Outcomes Analysis view (LOAs), and 3) Graduate Attributes Analysis (GAAs) view. The paper presents some principles related to the proposed system, demonstrates its multiple user interfaces, and digs more into OBA analytics and its proposed closed-loop continues improvement process. The objective of the proposed system and its underlying framework is to set new grounds for the accreditation process by making it more appealing, more economical, and more fruitful for all involved stakeholders.
Simplified Approach for Formula SAE Car Suspension Design and Component Size Optimization Using Finite Element Method
Authors: Subedi Subodh , Logan Joshua , Zahui Marcellin
Published: January 2018

Multiple parts with varying degrees of freedom create complexity in the analysis and design of car suspension. Formula SAE® teams design their cars based on the governing rules for competition every year. A proper selection of suspension components, body weight and geometry is required for well-designed racecar. Handling of a car during cornering must be carefully considered during design because of the presence of both lateral and longitudinal accelerations. A calculated balance has to be made with the placement and size of each of the suspension components. One critical component of the suspension is the Anti Sway Bar (ASB), which stabilizes the car during cornering. Simplified 3-D CAD model of an open wheel formula style car is created and analyzed for performance with and without ASB. The results indicate a superior control over the car during cornering when ASB are installed. Static analysis of the different suspension components were carried out using the maximum dynamic loads generated during rigid dynamic simulation. The objective of the static structural analysis is to examine the suitability of size, material and attachments to the chassis of these components. The results of the analysis presented here are validated with theoretical values and other results in literature. This work is an attempt to seek a simple approach for designing and analyzing a Formula SAE® racecar.
Determination of Optimum Hollowness of Normally Loaded Circular and Square Rings With Central Holes
Authors: Subedi Subodh , Zahui Marcellin
Published: January 2018

Hollowness of loaded members has been investigated using rings and square plates with central hole under normal compressive loads. The objective is to define the relative size of the central hole or optimum hollowness that will not compromise the load carrying capability of the rings and plates. Hollowness is thus defined as the volume percentage of measurable void in load carrying member. The work presented here uses finite element analysis to plot the radial and transverse stresses of a ring and a square plate with central hole versus the radius the hole or hollowness. The observations from the numerical analysis are further confirmed with experimental verification using strain gages. Seven rings and seven plates are normally loaded between two plates while the radial and transverse strains are measured. The derived stress are plotted with respect to hollowness. The plots show a moderate increase in stresses up to about 35% to 40% hollowness in both finite element and experimental results. Above these values, which represent the optimum hollowness, the stresses increase along a steep curve. These results indicate that some load carrying or transmitting machine components can be fabricated with measurable voids leveraging recent advances in Additive Manufacturing.
Dynamics During Speed Ratio Change of a Double Roller Full Toroidal Traction Drive
Authors: Roy Hardik , Maiti Rathindranath
Published: January 2018

The dynamics of the speed ratio change process of a double roller full toroidal variator (DFTV) is presented. Speed ratio variation process is observed by finding settling time and efficiency during the ratio variation. A numerical model is developed and simulated using computer software. Contact analyses between roller and discs are based on Hertz theory. The traction and spin moment coefficients are estimated using elasto-hydrodynamic lubrication (EHL) theory. Equation for maximum acceleration of output shaft is derived in terms of maximum output torque. Finally, a procedure to obtain maximum efficiency keeping certain dynamic speed ratio change requirements is discussed.
Numerical Investigation on the Dynamics of a Microparticle Pair Traveling in Confined Flow
Authors: Yuan Chen , Pan Zhenhai , Wu Huiying
Published: January 2018

In recent years, particle hydrodynamic focusing and ordering in a confined microchannel has been developed as a promising technique in lab-on-a-chip systems such as microparticle/cell separation, on-chip flow cytometry and detection. During the focusing, the uniformly distributed finite-sized particles from the channel inlet migrate across streamlines to several equilibrium positions according to the balance between series of hydrodynamic lift forces. While most studies in literature focus on single particle’s motion in the hydrodynamic focusing process by considering particle-liquid interactions, very few of them investigate particle-particle interactions, which is important in particle ordering and manipulation at high throughput. In this study, we use an immersed boundary (IB) - lattice Boltzmann (LB) coupled model to investigate the dynamic behaviors of a particle pair traveling through a square microchannel. The utilized numerical model retains the advantages of both LBM and IBM, which can accurately model the momentum exchange between liquid and particles, and conveniently treat complex geometry and movement of liquid-particle surfaces. By conducting numerical simulations, the time-dependent dynamic behaviors of particle pairs, including trajectories and interactions from initial rest condition to final quasi-equilibrium condition are obtained. Influences of important factors, such as Reynolds number and particle sizes on particles’ motions are discussed and the underlying physical mechanisms of particle-particle interactions are revealed in-depth.
Non-Model-Based Multiple Damage Identification of Beams Under Spatially Dense Vibration Measurement
Authors: Chen Da-Ming , Xu Y. F. , Zhu W. D.
Published: January 2018

An effective non-model-based multiple damage identification method for beams by using a continuously scanning laser Doppler vibrometer (CSLDV) system is presented. Velocity response of a beam along a scan line under sinusoidal excitation is measured by the CSLDV system and a spatially dense operating deflection shape (ODS) of the beam along the scan line is obtained by the demodulation method from velocity response. The ODS of an associated undamaged beam is obtained by using a polynomial with a proper order to fit the ODS from the demodulation method. The curvature of an ODS (CODS) is used to identify abnormality induced by multiple damage. A curvature damage index (CDI) using differences between CODSs associated with ODSs that are obtained by the demodulation method and the polynomial fit is proposed to identify multiple damage. An auxiliary CDI obtained by averaging CDIs at different excitation frequencies is defined to further assist identification of multiple damage. Experiments on three beams with three damage on each beam in the form of three small cuts are conducted. Widths and depths of the three damage are varied from 3 mm to 9 mm with an increment of 3 mm and from 5% of thickness reduction to 15% with an increment of 5%, respectively, and their effects on ODSs, CODSs, and CDIs are investigated. Three frequencies close to natural frequencies of the beams and one randomly selected frequency that is not close to any natural frequencies of the beams are used as sinusoidal excitation frequencies. Each damage is successfully identified near regions with consistently high values of CDIs at different excitation frequencies when the damage is not close to a nodal point of an ODS. The three damage on each beam is successfully identified with the auxiliary CDI by obvious peaks at locations of the three damage.
Statics and Dynamics of an Aortic Segment Considering Residual Stresses
Authors: Breslavsky Ivan , Amabili Marco , Tubaldi Eleonora , Ruimi Annie
Published: January 2018

Static and dynamic analysis of a circular cylindrical shell that models a segment of human aorta is carried out in this study. The shell is assumed to have three hyperelastic layers with residual stresses. Material data and residual stresses are taken from the literature from human toracic descending aorta. The material model is the Holzapfel-Gasser-Ogden (HGO). Dissipation is modelled by viscoelasticity. The dynamic load is given by a pulsating pressure reproducing the physiological pressure during the heart beating. The inertial effect of the contained blood fluid is taken into account. Under the static pressure, the initially soft shell becomes much stiffer, which is a common feature of soft biological tissues. The nonlinear dynamics is not particularly complicated, due to the significant damping.
Investigating the Effects of Sodium Chloride Particles on Thermoelectric Properties of Bismuth Telluride
Authors: Alexander T. , Rahman M. , Asmatulu R.
Published: January 2018

Cylindrical pellets of near stoichiometric bismuth telluride (Bi2Te3) powder with NaCl particles were made using a cold pressing and pressureless sintering technique. The sodium chloride was leached out from the samples in hot water, resulting in porous samples with varying levels of porosity. The electrical conductivity, Seebeck coefficient, and thermal conductivity were measured at room temperature using a testing apparatus designed and built by the researcher, both before and after the leaching of sodium chloride. From this data, the figure of merit was calculated. Samples of pure bismuth telluride (0% NaCl) served as the baseline samples for comparison. Both the presence of NaCl and pores were efficient at increasing the dimensionless figure of merit. Porous samples initially containing 20% NaCl had a 37.55% higher figure of merit compared to baseline samples, and an 89.07% increase in the figure of merit was seen from the solid samples with NaCl inclusions at a concentration of 30% by volume. The electrical conductivity was negatively affected by both inclusions and porosity, but significant increases in Seebeck coefficient, and reduced thermal conductivity were significantly enough for an overall increase in dimensionless figure of merit. The figure of merit for the baseline sample was approximately 0.18, and the highest values observed for the NaCl inclusion and porous samples were 0.34 and 0.25 respectively. These values are far less than that of what is considered a state of the art thermoelectric material, but the materials and methods used were simple, inexpensive, and scalable, showing great potential for applicability for use with optimized thermoelectric materials in hopes of further increasing their figure of merit.
Identification and Ranking of Noise Sources on a Jumbo Drill Machine During Operation
Authors: Camargo Hugo E. , Peterson Jeffrey S. , Azman Amanda S.
Published: January 2018

Noise-induced hearing loss (NIHL) is the second most prevalent illness in the mining industry. According to a study conducted by the National Institute for Occupational Safety and Health (NIOSH), in which over 42,000 audiograms from metal/nonmetal miners were analyzed, approximately 70% of miners have hearing impairment as compared to 9% of non-occupationally noise-exposed workers. One of the machines used extensively in metal/nonmetal mines responsible for high noise exposure levels of its operators is the jumbo drill, used to drill holes at the mines for blasting purposes. In this context, NIOSH is conducting research to develop engineering noise controls for jumbo drills that would reduce the prevalence of hearing loss among operators of this equipment. The first step of the noise control development process consists of identifying and ranking dominant noise sources present during operation of the jumbo drill. To this end, a noise study was conducted at NIOSH’s laboratories in which a microphone phased array system was used to identify dominant noise sources, and the transfer path analysis method was used to rank these sources based on their contribution to the operator location. Results showed that the drill string and the drilling mechanism — known as the drifter — are the dominant sound-radiating components in the operation of the jumbo drill.
Campylobacter jejuni Colonization in the Crow Gut Involves Many Deletions within the Cytolethal Distending Toxin Gene Cluster
Authors: Sen Keya , Lu Jingrang , Mukherjee Piyali , Berglund Tanner , Varughese Eunice , Mukhopadhyay Asish K.
Published: January 2018

Campylobacterspp. are major causes of gastroenteritis worldwide. The virulence potential ofCampylobactershed in crow feces obtained from a roost area in Bothell, Washington, was studied and compared with that from isolates from other parts of Washington and from a different crow species 7,000 miles away in Kolkata, India.Campylobacterorganisms were isolated from 61% and 69% of the fecal samples obtained from Washington and Kolkata, respectively, and were confirmed to beC. jejuni. The cytolethal distending toxin (CDT) gene cluster from these isolates revealed a truncated sequence of approximately 1,350 bp. Sequencing of the gene cluster revealed two types of mutations: a 668-bp deletion acrosscdtAandcdtBand a 51-bp deletion withincdtB. Some strains had additional 20-bp deletions incdtB. In either case, a functional toxin is not expected; a functional toxin is produced by the expression of three tandem genes,cdtA,cdtB, andcdtC. Reverse transcriptase PCR with total RNA extracted from the isolates showed no expression ofcdtB. A toxin assay performed with these isolates on HeLa cells failed to show cytotoxic effects on the cells. However, the isolates were able to colonize the chicken ceca for a period of at least 4 weeks, similar to that of a clinical isolate. Other virulence gene markers, flagellin A and CadF, were present in 100% of the isolates. Our study suggests that crows carry the bacteriumC. jejunibut with a dysfunctional toxin protein that is expected to drastically reduce its potential to cause diarrhea.

IMPORTANCECampylobacters are a major cause of gastroenteritis in humans. Since outbreaks have most often been correlated with poultry or unpasteurized dairy products, contact with farm animals, or contaminated water, historically, the majority of the studies have been with campylobacter isolates from poultry, domestic animals, and human patients. However, the bacterium has a broad host range that includes birds. These reservoirs need to be investigated, because the identification of the source and a determination of the transmission routes for a pathogen are important for the development of evidence-based disease control programs. In this study, two species of the human-commensal crow, from two different geographical regions separated by 7,000 miles of land and water, have been examined for their ability to cause disease by shedding campylobacters. Our results show that the crow may not play a significant role in campylobacteriosis, because the campylobacter organisms they shed produce a nonfunctional toxin.
Genome Sequence of a Novel Strain of a Phasi Charoen-Like Virus Identified in Zhanjiang, China
Authors: Zhang Xiaomin , Jin Tao , Huang Yalan , Huang Suibin , Yang Fan , Lin Peng , Liu Yang , Huang Dana , Wu Chunli , Xie Jianbin , Cheng Jinquan , Wan Chengsong , Zhang Renli
Published: January 2018

Here, we report the genome sequence of a novel strain of a Phasi Charoen-like virus, isolated from
Aedes aegypti
mosquitoes caught in Zhanjiang province of China. Phylogenetic analysis suggested that this virus belongs to a new genus,
Goukovirus
, in the family
Bunyaviridae
. This is the first reported genome sequence of a Phasi Charoen-like virus identified in China.
Genome Sequences of Four Cluster P Mycobacteriophages
Authors: Doyle Erin L. , Fillman Christy L. , Reyna Nathan S. , Tobiason Deborah M. , Westholm Daniel E. , Askins Jonathan L. , Backus Brittany P. , Baker Ashlynn C. , Ballard Harrison S. , Bisesi Paul J. , Bond Logan , Byrnes Deanna , Carlstedt Hannah , Dodson Kinnon S. , Fallert Megan J. , Foster Kyla J. , Games Daniel N. , Grams Tristan R. , Guild Nancy A. , Hurd Autumn , Iwata Nicholas , Kepler Cassidy R. , Krenzke Lucinda R. , Luekens Kelly , Lewis Jackie , McEntee Cali , McGee Justin C. , Nalley Noah , Plymale Ruth C. , Prochaska Jade , Rogers Reid G. , Schipper Jessica B. , Snyder Kelsey , Uhrich Kali , Vermillion Chelsey D. , Vickers Sarah K. , Wenta Meredyth D. , Yates Tyler Z. , Young Chas F. , Stoner Ty H. , Pope Welkin H. , Jacobs-Sera Deborah , Garlena Rebecca A. , Russell Daniel A. , Cresawn Steven G. , Hatfull Graham F.
Published: January 2018

Four bacteriophages infecting
Mycobacterium smegmatis
mc
2
155 (three belonging to subcluster P1 and one belonging to subcluster P2) were isolated from soil and sequenced. All four phages are similar in the left arm of their genomes, but the P2 phage differs in the right arm. All four genomes contain features of temperate phages.
Complete Genome Sequencing of
Acinetobacter
sp. Strain LoGeW2-3, Isolated from the Pellet of a White Stork, Reveals a Novel Class D Beta-Lactamase Gene
Authors: Blaschke Ulrike , Skiebe Evelyn , Kaatz Michael , Higgins Paul G. , Pfeifer Yvonne , Wilharm Gottfried
Published: January 2018

Whole-genome sequencing of
Acinetobacter
sp. strain LoGeW2-3, isolated from the pellet of a white stork (
Ciconia ciconia
), reveals the presence of a plasmid of 179,399 bp encoding a CRISPR-Cas (clustered regularly interspaced short palindromic repeats and associated genes) system of the I-F type, and the chromosomally encoded novel class D beta-lactamase OXA-568.
Whole-Genome Sequences of
Brucella melitensis
Strain QH61, Isolated from Yak in Qinghai, China
Authors: Cao Xiaoan , Li Zhaocai , Lou Zhongzi , Fu Baoquan , Liu Yongsheng , Shang Youjun , Zhou Jizhang , Jing Zhizhong
Published: January 2018

The facultative intracellular Gram-negative bacterium
Brucella melitensis
causes brucellosis in domestic and wild mammals.
Brucella melitensis
QH61 was isolated from a yak suffering from abortion in 2015 in Qinghai, China. Here, we report the whole-genome sequence of
B. melitensis
strain QH61.
Draft Genome Sequences of
Bifidobacterium
Strains N4G05 and N5G01, Isolated from the Human Vaginal Microbiome
Authors: Freitas Aline C. , Hill Janet E.
Published: January 2018

We report here the draft genome sequences of
Bifidobacterium
strains N4G05 and N5G01, isolated from the human vaginal microbiome. Genome sequences were obtained by
de novo
assembly from high-quality reads. Both strains were closely related to
Bifidobacterium kashiwanohense
based on barcode marker sequences and average nucleotide identity analysis.
Issues and challenges for research in major trauma
Authors: Swain Sharon Ann , Stiff Graham
Published: January 2018

The starting point for evidence-based guidelines is the systematic review and critical appraisal of the relevant literature. This review highlights the risk of bias identified while critically appraising the evidence to inform the National Institute of Health and Care Excellence guideline on the assessment and initial management of major trauma.
Addressing complexity in population health intervention research: the context/intervention interface
Authors: Minary Laetitia , Alla François , Cambon Linda , Kivits Joelle , Potvin Louise
Published: January 2018

Background

Public health interventions are increasingly being recognised as complex and context dependent. Related to this is the need for a systemic and dynamic conception of interventions that raises the question of delineating the scope and contours of interventions in complex systems. This means identifying which elements belong to the intervention (and therefore participate in its effects and can be transferred), which ones belong to the context and interact with the former to influence results (and therefore must be taken into account when transferring the intervention) and which contextual elements are irrelevant to the intervention.

Discussion

This paper, from which derives criteria based on a network framework, operationalises how the context and intervention systems interact and identify what needs to be replicated as interventions are implemented in different contexts. Representing interventions as networks (composed of human and non-human entities), we introduce the idea that the density of interconnections among the various entities provides a criterion for distinguishing core intervention from intervention context without disconnecting the two systems. This differentiates endogenous and exogenous intervention contexts and the mediators that connect them, which form the fuzzy and constantly changing intervention/context interface.

Conclusion

We propose that a network framework representing intervention/context systems constitutes a promising approach for deriving empirical criteria to delineate the scope and contour of what is replicable in an intervention. This approach should allow better identification and description of the entities that have to be transferred to ensure the potential effectiveness of an intervention in a specific context.
Modelling impacts of recent warming on seasonal carbon exchange in higher latitudes of North America
Authors: Mekonnen Zelalem A. , Grant Robert F. , Schwalm Christopher
Published: January 2018

An ecosystem model, ecosys, has been used to examine the effects of recent warming on carbon exchange in higher latitudes of North America. Model results indicated that gradual warming during the past 30 years has increased net ecosystem productivity (NEP) and leaf area index (LAI). Spring increases in LAI advanced by 2.3 days decade−1 and decreases in autumn were delayed by 5.0 days decade−1 from 1982 to 2006. These advances and delays were corroborated by similar trends observed in the normalized difference vegetation index. NEP modelled during this period increased at an average rate of 17.6 Tg C decade−1. Increasing carbon losses modelled with soil warming in autumn, when thaw depth was greatest, offset 34% of increasing carbon gains modelled in spring. If autumn warming continues, carbon losses in this season may further offset enhanced carbon sequestration in spring.