bluuebunny/crossref_metadata_2025 huggingface dataset:
Cost Optimisation in Risk Reduction Management Based on Gross Disproportionation Concept
Authors: Marín Alejandro , Hernández Jon
Published: November 2019

Gross Disproportionation concept is used as indicator once risk reduction measures are required. This indicator shows that a measure must be implemented if its cost (i.e. Capital Expenditure), is not grossly disproportionate if compared to benefits — represented by casualties suppression — reached by the measure. Due to this, a risk reduction measure is reasonable feasible unless its cost is highly disproportionate in comparison to its benefits.

In hydrocarbon transportation industry, benefits represent the avoided cost if threats take place; on the other hand, for risk mitigation cost estimation, the cost per casualty averted must be accounted. The latter, provides a global cost of the mitigation measure adopted in relation to the direct cost of construction, with the reduction of the level of risk (i.e. social risk) and with the expected design period for that measure. In this last concept, the higher the reduction in the level of risk or the longer the design period of the mitigation measure, the lower the cost per casualty averted, a fact that reflects an effective mitigation measure in terms of risk reduction and its durability.

This document shows, from a case study, how the application of the concept of grow disproportionation allows to select the type of optimal intervention over Ocensa’s pipeline, with the most favorable relation between cost and benefit, and the effective risk reduction level.
Risk Management of Pipeline Breakage at River Crossings Through Quantitative Analysis of the Threat, Vulnerability and Consequences
Authors: Debandi Carlos , Martearena Fernando , Roth Natalia
Published: November 2019

The floods of rivers and streams are among the threats that most frequently cause technological accidents. A quantitative analysis of the risk of breakage of pipelines in crossings with channels is presented.

The proposed methodology evaluates the risk of rupture of the pipeline quantifying both the threat of being discovered and its vulnerability to hydrodynamic forces and those due to vortex shedding.

Decision-making for risk mitigation is complemented by the evaluation of the consequences that breakage can produce in the environment and in the activity of the operator, that is, the assessment of the severity of the risk. To this end, the impact is quantified in terms of the extent of the damage caused and the economic losses due to the stoppage of production and the remediation costs.

Finally, risk management is developed, which includes actions to mitigate the hazard and vulnerability, the priority of each of them and the implementation and monitoring plans.

The application of the proposed methodology achieves the early identification and reduction of risk of breakage, knowledge of the state of the crosses, objectivity and reliability in the assignment of risk levels and the correct allocation of resources for mitigation.
Enhancing Geohazard Management Practice for South American Pipelines
Authors: Porter Michael , Scordo Elisa , Barlow Pete , Welkner Daniela , Leach Miguel
Published: November 2019

Pipeline geohazard management practices and technologies have evolved rapidly over the past 15 years in step with industry’s drive towards zero failures. This paper describes the evolution in geohazard management for pipelines since the early 2000’s and describes how technology and management practices are currently being adapted to accommodate South American site conditions and data sources. It ends by outlining a possible framework for industry, regulatory and academic collaboration within South America that offers the potential for another step-function improvement in pipeline safety.
Investigations for Wax Coated 3D Printed Hybrid Patterns for Partial Dentures
Authors: Boparai Kamaljit Singh , Singh Gurpartap , Singh Rupinder , Singh Sarabjit
Published: November 2019

In this work, 3D printed master patterns of acrylonitrile butadiene styrene (ABS) thermoplastic material have been used for the preparation of Ni-Cr based functional prototypes as partial dentures (PD). The study started with patient specific three dimensional (3D), CAD data (fetched through scanning). This data was used for preparation of .STL file for printing of master patterns on fused deposition modeling (FDM) setup. The 3D printed master patterns were further wax coated to reduce the surface irregularities (as cost effective post processing technique). The hybrid patterns were subjected to investment casting for the preparation of Ni-Cr based PD. The finally prepared functional prototypes as PD were optimized for dimensional accuracy, surface finish and surface hardness as responses. The results are visualized and supported by photomicrographs and in-vitro analysis.
Experimental Investigation on Laser Peening of Additively Manufactured Ti6Al4V Alloy
Authors: Hu Yongxiang , Lai Mengqi , Yao Zhenqiang
Published: November 2019

Laser additive manufacturing is widely utilized to fabricate Ti6Al4V alloy, but post-processing is necessary to improve its performance for fatigue resistance of some critical components. This paper proposes laser peening (LP) as an effective way to improve the surface integrity of Ti6Al4V alloy fabricated by direct laser deposition (DLD). After laser peening, little difference of surface roughness is observed. Compressive residual stresses are induced on the top surface layer. The maximum value of compressive residual stress is about −520 MPa and the compressive state extends to the depth of 0.60 mm. In addition, the relative densities of specimen are measured using the Archimedes method. The average porosity is observed to decrease due to plastic deformation at the surface layer. Results of fatigue test show that the service cycle can be improved about three times.
Preliminary Study on Multiscale Modeling and Simulation of Liquid-Assisted Laser Beam Machining
Authors: James Sagil , Patil Aakash
Published: November 2019

Liquid Assisted Laser Beam Machining (LA-LBM) process is used as an alternative to existing Laser beam machining (LBM) process to provide solutions to many of the problems associated with the extreme heat of the laser. In this research, the thermal effects of laser and hydrodynamics effects of the liquid medium in the LA-LBM process are investigated using a multiscale modeling and simulation approach. This preliminary study aims to understand the interactions between pulsed and continuous laser heat flux during the LA-LBM process. The results of the study would augment our existing knowledge of the complex mechanisms involved in the LA-LBM process.
Multizone Rapid Thermal Processing to Overcome Challenges in Carbon Nanotube Manufacturing by Chemical Vapor Deposition
Authors: Lee Jaegeun , Abdulhafez Moataz , Bedewy Mostafa
Published: November 2019

For the scalable production of commercial products based on vertically aligned carbon nanotubes (VACNTs), referred to as CNT forests, key manufacturing challenges must be overcome. In this work, we describe some of the main challenges currently facing CNT forest manufacturing, along with how we address these challenges with our custom-built rapid thermal processing chemical vapor deposition (CVD) reactor. First, the complexity of multistep processes and reaction pathways involved in CNT growth by CVD limits the control on CNT population growth dynamics. Importantly, gas-phase decomposition of hydrocarbons, formation of catalyst particles, and catalytic growth of CNTs are typically coupled. Here, we demonstrated a decoupled recipe with independent control of each step. Second, significant run-to-run variations plague CNT growth by CVD. To improve growth consistency, we designed various measures to remove oxygen-containing molecules from the reactor, including air baking between runs, dynamic pumping down cycles, and low-pressure baking before growth. Third, real-time measurements during growth are needed for process monitoring. We implement in situ height kinetics via videography. The combination of approaches presented here has the potential to transform lab-scale CNT synthesis to robust manufacturing processes.
Additive Manufacturing-Based Adaptive Dynamic Parameter Characterization by Using Pressure-Fed Flexure Mechanisms
Authors: Lee ChaBum , Han JaeMin , Kim Gyu Ha
Published: November 2019

This paper presents dynamic characteristics of pressure-fed flexure mechanisms with the additively manufactured internal fluidic channels. Additive manufacturing (AM) technology makes use of the mechanical design flexibility that can effectively control the material distribution in terms of stiffness and damping of the flexures. Five different fluidic channel geometry (circular, semicircular, inverse-semicircular, triangular, and inverse-triangular) with the same cross-sectional area was designed and fabricated inside of one-dimensional cantilever beam (10 × 30 × 100 mm3). Stiffness, damping ratio and natural frequency of each cantilever according to varying air pressure condition from 14.7 psi (atmospheric pressure) to 75 psi were characterized, and at the same time dynamic behaviors of each cantilever were identified by using dynamic signal analyzer. In addition, dynamic characteristics of water-filled flexure mechanism were compared to those of air-filled cases. As a result, the internal channel geometry and filled-in media in the channel have significant influences to determine dynamic characteristics of flexure mechanisms. Such pressure-fed mechanisms can be considered in the first stage of AM flexure design and fabrication processes to adaptively control dynamic behaviors in an easy, convenient and low-cost manner.
Springback Analysis of Hybrid Materials Created Through Alternative Layup Processes
Authors: Mamros Elizabeth M. , Nikhare Chetan P.
Published: November 2019

Various industry partners, particularly those in the automotive and aerospace industries, are continuing to grow their businesses and are seeking ways to improve their manufacturing processes. Some preliminary research has been conducted concerning the use of hybrid materials as a solution, but further analysis is required before these materials can be rolled out into industry universally. Two major benefits of potentially swapping out metal parts for hybrid (metal and composite) components are light weighting and cost reduction, which are currently two major objectives for these industries. It is imperative to understand the properties of the materials used in each manufacturing process as these properties will determine the result of each operation and ultimately the final product. A number of components are manufactured with sheet metal forming processes, and a commonly experienced, unwarranted effect is springback. Springback occurs when the die is removed following a forming operation, and the deformed part transforms its shape as a result of the elastic material properties. A component affected by springback may negatively affect future manufacturing processes, such as incorrect alignment during assembly. To further investigate a solution to this manufacturing defect, trilayer hybrid materials with metal and composite layers are considered. Due to complications resulting from the layup process in previous results, new techniques are required to eliminate delamination and gather additional springback measurements following channel bending tests. Trilayer sample compositions are composite metal composite or metal composite metal sandwiches. The layup techniques under consideration are resin plus hardener, a pillow method, and an enhanced adhesive mixture. The results from these experiments will support the movement to bring hybrid materials into manufacturing universally and will demonstrate the potential benefits of utilizing new layup techniques in the assembly of these materials.
Robots in the Industrial Internet: A Cloud-Based Approach Based on Gateways
Authors: Wang Xi Vincent , Wang Chen , Wang Lihui
Published: November 2019

In the context of Industrial Internet, connectivity is a must during system construction as it provides the possibility of sharing the hardware data with the network, and accessing the hardware from other systems or devices. An efficient communication approach is the highest priority to deploy a successful technology like Industry 4.0, Industrial Internet, Internet of Things, etc.. Thus in this research, a system integration method is presented using industrial robots as the test scenario. Cloud and gateway technologies are utilised to achieve high-performance connectivity, integration and security. Multiple deployment models are developed for public, private and hybrid cloud scenarios. During implementation, the Universal Robot 5 is utilised as the test robot integrating to the KTH cloud system in Sweden. The results are quantifiably evaluated and discussed. The proposed approach also contributes to the Cloud Robotics research by proposing novel system structures and integration methods.
An Improvement of Physics Based Compressive Sensing With Domain Decomposition to Monitor Temperature in Fused Filament Fabrication Process
Authors: Lu Yanglong , Wang Yan
Published: November 2019

Sensors in manufacturing play an important role in monitoring and improving the quality of products. However, the rising cost of sensing subsystems and the bandwidth limitation of data transmission are challenges in modern manufacturing systems, which rely on a large number of sensors. Recently, a physics based compressive sensing (PBCS) approach was proposed to monitor manufacturing processes with reduced number of sensors and amount of collected data. PBCS significantly improves the compression ratio from classical compressed sensing by incorporating the knowledge of physical phenomena in specific applications. In this paper, a modified orthogonal matching pursuit (OMP) recovery algorithm, called constrained OMP, is developed for PBCS when coherence exists between the measurement matrix and basis matrix. The efficiency of PBCS recovery is also improved by introducing a domain decomposition approach, which can reduce the size of model matrices, such as the conduction matrix and mass matrix in the transient heat transfer application. The improved PBCS with the domain decomposition method is used to monitor the temperature distribution in the cooling process and real-time printing process of fused filament fabrication.
Glues Make Gummy Metals Easy to Cut
Authors: Udupa Anirudh , Sugihara Tatsuya , Mann James B.
Published: November 2019

Metals such as Cu, Al, Ni, Ta and stainless steels, despite their softness and ductility, are considered difficult to machine. This is due to large cutting forces and corresponding formation of a very thick chip during cutting and hence these metals are referred to as “gummy”. Their poor machinability of these materials arises because of an unsteady and highly redundant mode of plastic deformation referred to as sinuous flow. The prevailing plastic deformation mode during machining can be overcome by the application of certain coatings and chemical media on the un-deformed free surface of the workpiece ahead of the cutting process. Using in-situ imaging and concurrent force measurements we present two different mechanochemical routes through which these media can improve machinability. The first route, which requires chemicals that adhere to the metal surface, such as glues and inks, improves cutting by inducing a change in the local plastic deformation mode — from sinuous flow to one characterized by periodic fracture or segmented flow. The second route, which requires chemicals that can react with the workpiece to form a low-friction layer, changes the sinuous flow mode to a smooth, laminar one. Both routes decrease cutting forces by more than 50% with order of magnitude improvement in surface texture as characterized by measured roughness and defect density. The results suggest a broad range of opportunities for improving performance of machining processes for many difficult-to-cut gummy metals.
Custom Skull Cap With Precision Guides for Deep Insertion of Cellular-Scale Microwire Into Rat Brain
Authors: Chen Lei , Hartner Jeremiah , Van Dyke David , Dong Tianshu , Watson Brendon , Shih Albert
Published: November 2019

To understand the brain functioning mechanisms, electrophysiological methods represent the most mature approach for recording brain dynamics at millisecond timescales in either local or large spatial scales. Microwire-based microelectrode arrays (MEAs) are a well-established tool for chronic recording of electrophysiologic signals and furthermore have the advantage of minimal brain damage if constructed from cellular-scale (4–100 μm neuron diameter) microwires. However, such cellular-scale MEAs are not widely used by neuroscientists, especially on deep insertion cases, due to the barrier of implantation. Efforts to reduce the size of microwires bring collateral difficulties due to buckling during penetration through membranes (dura/pia) and consequent inability to implant deeply into the brain or in a manner that leaves intact protective biolayers such as the dura mater. In this paper, we developed a custom skull cap with precision guide holes to stabilize the brain and dura, provide sufficient support to microwire along the insertion path, and minimize the unsupported length of microwire during dura penetration and deeper insertion. A cap matched to individual skull anatomy with offset for brain stabilization was designed based on computed tomography (CT) scan of the rat head and fabricated by stereolithography. Micro-milling and wax molding were conducted to fabricate precision insertion guide inside the cap. Animal surgical studies were conducted to test the performance of skull cap and insertion guide. Rats with skull cap attached had survived for multiple weeks until sacrificed by experimenters. Through a test cube with precision guide, a 25 μm diameter tungsten microwire penetrated through the dura mater and was manually inserted over 10 mm into the brain without buckling. In comparison, without the precision guide, insertion of the same microwire caused over 2 mm dimpling of the dura without penetration and finally led to wire buckling. Results showed that the custom skull cap with precision guide holes enabled the insertion of cellular-scale microwire electrodes deep into the brain through the dura mater without buckling.
A Decision-Level Data Fusion Approach to Surface Roughness Prediction
Authors: Wei Yupeng , Wu Dazhong , Terpenny Janis
Published: November 2019

To improve the quality of additively manufactured parts, it is crucial to develop real-time process monitoring systems and data-driven predictive models. While various sensor- and image-based process monitoring methods have been developed to improve the quality of additively manufactured parts, very limited research has been conducted to predict surface roughness. To fill this gap, this paper presents a decision-level data fusion approach to predicting surface roughness in the fused deposition modeling (FDM) process. The predictive models are trained by the random forests method using multiple sensor signals. A decision-level data fusion method is introduced to integrate sensor data sources. Experimental results have shown that the decision-level data fusion approach can predict surface roughness in FDM with high accuracy.
Structure and Deformation of Gradient Metal Foams Produced by Machining
Authors: Qiao H. , Murthy T. G. , Saldana C.
Published: November 2019

The effects of surface structure on mechanical performance for open-cell aluminum foam specimens was investigated in the present study. A surface gradient for pore structure and diameter was introduced into open cell aluminum foams by machining-based processing. The structure changes in the strut and pore network were evaluated by computed tomography characterization. The role of structure gradients in affecting mechanical performance was determined using digital volume correlation and in situ compression within the computed tomographic scanner. These preliminary results show that the strength of these materials may be enhanced through surface structural gradients.
Additive Manufacturing Processes for Infrastructure Construction: A Review
Authors: Bhardwaj Abhinav , Jones Scott Z. , Kalantar Negar , Pei Zhijian , Vickers John , Wangler Timothy , Zavattieri Pablo , Zou Na
Published: November 2019

Additive manufacturing (AM) has had an enormous impact in the manufacturing sector. Its role has evolved from printing prototypes to manufacturing functional parts for a variety of applications in the automotive, aerospace, and medical industries. Recently, AM processes have also been applied in the infrastructure construction industry. Applications of AM processes could bring in significant improvements in infrastructure construction, specifically in the areas of productivity and safety. It is desirable to have a review on the current state of emerging AM processes for infrastructure construction as well as existing gaps in this field. This paper reviews AM processes in infrastructure construction. It discusses the process principle, application examples, and gaps for each of the AM processes.
Forces in Deep-Hole Bone Drilling
Authors: Lee JuEun , Matsumoto Zachary , Chu Serena Y.
Published: November 2019

Deep-hole bone drilling is performed in many surgical implantation procedures. Unlike bone drilling of shallow holes (commonly 5 to 7 mm in depth), deep-hole bone drilling requires a larger hole depth (i.e., up to a depth of approximately 35 mm in cochlear implantation) using a high ratio of the length to diameter of the drill bit. This paper presents an experimental investigation of forces in deep-hole bone drilling. The hypothesis of this study was that the forces signals show a sudden transition with a considerable amount of increases during deep-hole bone drilling process. The objective of this study was to understand bone drilling behaviors as drilling depth increases. Drilling tests were performed on bovine cortical bones using a 2.5 mm diameter drill bit with a spindle speed of 3000 rpm and feed rates of 0.05 and 0.1 mm/rev at a drilling hole depth of 36 mm. The force signals showed two distinct states, which were referred to as normal and abnormal states in this study. After showing a constant force signals in the normal state once the drill tip became fully engaged in bone cutting, from a certain drilling depth, the force signals considerably increased, which is referred to abnormal state. This study observed that the chip morphology varies with respect to drilling depth, showing fragmented chips in the normal state and powdery chips in the abnormal state. The results of this study indicate that the abrupt increase in the force signals in the abnormal state is mainly attributed to chip clogging inside the flutes as the drilling depth increases.
Binder Jetting Additive Manufacturing of Metals: A Literature Review
Authors: Li Ming , Du Wenchao , Elwany Alaa , Pei Zhijian , Ma Chao
Published: November 2019

Binder jetting, also known as 3D printing, is an additive manufacturing (AM) technology utilizing a liquid-based binding agent to selectively join the material in a powder bed. It is capable of manufacturing complex-shaped parts with a variety of materials. This paper provides an overview of binder jetting of metals with a discussion about the knowledge gaps and research opportunities. The review deals with two parameter categories in terms of the material and process and their impacts. The achieved density, dimensional accuracy, and mechanical strength are summarized and analyzed. Further in-depth consideration of densification is discussed corresponding to various attributes of the packing, printing, and sintering behaviors. Though binder jetting has attracted increasing attention in the past several years, this fabrication process is not well studied. The understanding of powder spreading process and binder-powder interaction is crucial to the development of binder jetting but insufficient. In addition, the lack of investigation on the mechanical behavior of binder jetting metal part restricts the actualization of its wide-range applications.
Selective Laser Melting of Curved Surface Metal Parts: A Fundamental Study on Surface Finish and Dimensional Accuracy
Authors: Alelaumi Shrouq , Zhou Yue , Khoshkhoo Ali , Ning Fuda
Published: November 2019

Additive manufacturing (AM) of metal has been experiencing rapid growth in recent years by employing a variety of techniques. Among them, selective laser melting (SLM) of metal exhibits advantages in terms of its capabilities to build complex geometries, good surface finish, and high dimensional accuracy. Due to these benefits, SLM has demonstrated the ability to create metallic parts that can be applied in aerospace, automotive, and medical industries. However, most parts are geometrically complex with curved surface features, which would be difficult to be fabricated through traditional manufacturing methods. In order to increase the adoption and effectiveness of SLM for metal parts fabrication, the as-built surface finish and dimensional accuracy of the parts with curved surface features should be well understood. Great attempts have been made to investigate the surface texture of SLM as-built parts with various surface types. Most investigations characterize the surface texture of SLM-fabricated specimens with planar surface features. However, little is known about the surface finish and dimensional accuracy of SLM-fabricated metal parts with curved surfaces. Directly applying knowledge derived from planar surfaces to curved ones can be misleading. In this work, stainless steel 316L parts with curved surface features were built using SLM to examine the surface finish and dimensional accuracy. The results showed that 11 surface texture variables were significant at five different curvatures and the three most significant roughness variables were Sk, Spc, and Vmc. It was found that curvatures C1 and C5 significantly differed from the other curvatures (C2, C3, and C4) in all the 11 surface texture variables. In addition, the thickness of the as-built curved surface part at varied curvature locations would be almost constant.
Binder Jetting Additive Manufacturing of Ceramics: Feedstock Powder Preparation by Spray Freeze Granulation
Authors: Du Wenchao , Miao Guanxiong , Liu Lianlian , Pei Zhijian , Ma Chao
Published: November 2019

Objective of this study is to prepare the binder jetting feedstock powder by spray freeze drying and study the effects of its parameters on the powder properties. Binder jetting additive manufacturing is a promising technology for fabricating ceramic parts with complex or customized geometries. However, this process is limited by the relatively low density of the fabricated parts even after sintering. The main cause comes from the contradicting requirements of the particle size of the feedstock powder: a large particle size (> 5 μm) is required for a high flowability while a small particle size (< 1 μm) for a high sinterability. For the first time, a novel technology for the feedstock material preparation, called spray freeze drying, is investigated to address this contradiction. Using raw alumina nanopowder (100 nm), a full factorial design at two levels for two factors (spraying pressure and slurry feed rate) was formed to study their effects on the properties (i.e., granule size, flowability, and sinterability) of the obtained granulated powder. Results show that high pressure and small feed rate lead to small granule size. Compared with the raw powder, the flowability of the granulated powders was significantly increased, and the high sinterability was also maintained. This study proves that spray freeze granulation is a promising technology for the feedstock powder preparation of binder jetting additive manufacturing.
Geometric Deep Learning for Shape Correspondence in Mass Customization
Authors: Huang Jida , Sun Hongyue , Kwok Tsz-Ho , Zhou Chi , Xu Wenyao
Published: November 2019

Many industries, such as human-centric product manufacturers, are calling for mass customization with personalized products. One key enabler of mass customization is 3D printing, which makes the flexible design and manufacturing possible. However, personalized designs bring obstacles for the shape matching and analysis, owing to the high complexity and large shape variations. Traditional shape matching methods are limited to shape alignment, which cannot determine the intrinsic in-variance of mass customized models. To extract the deformations widely seen in mass customization paradigm and address the issues of alignment methods in shape matching, we redefine the geometry matching problem as a correspondence problem, and solve for the correspondence of all vertices on a queried shape to a reference shape. A state-of-the-art geometric deep learning method is used to learn the correspondence of a set of collected models. Through learning the intrinsic deformations of the products, the underlying variations of the shapes are extracted. We demonstrate the application of the proposed approach in orthodontics industry, and the experimental results show the effectiveness of the proposed method and the defined problem is favorably suitable for shape analysis in mass customization.
Rotary Ultrasonic Machining of CFRP Composites: Effects of Machining Variables on Workpiece Delamination
Authors: Chen Xiaoxu , Wang Hui , Hu Yingbin , Zhang Dongzhe , Cong Weilong , Burks Anthony R.
Published: November 2019

Carbon fiber reinforced plastic (CFRP) composites were widely used in machinery, automobile, and aerospace industries due to the superior properties of high stiffness, high strength-to-weight ratio, high fatigue resistance, and good wear resistance. In these applications, hole making on CFRP composites was needed for assembly purpose. In different hole making processes, delamination was considered as a crucial issue, leading to premature failure of products. Compared with the conventional CFRP hole making processes (such as twist drilling, milling, grinding, etc.), rotary ultrasonic machine (RUM) had advantages of low cutting force and torque, low surface roughness, and long tool life. Therefore, numbers of researchers worked on RUM processes. The reported investigations mainly focused on the effects of input variables (including machining variables, tool variables, and workpiece properties) on cutting force, torque, surface roughness, and tool life, etc. In addition, effects of cutting tool variables on delamination were also reported. However, there were no reported investigations on effects of machining variables on delamination in RUM of CFRP composites. This investigation, for the first time, reported the effects of ultrasonic power, tool rotation speed, and feedrate on delamination as well as its associated cutting force. Based on the experiments, the results showed that delamination decreased with ultrasonic power increasing, tool rotation speed increasing, or feedrate decreasing. The relationships between cutting force and delamination were also studied.
Predicting Part-Level Thermal History in Metal Additive Manufacturing Using Graph Theory: Experimental Validation With Directed Energy Deposition of Titanium Alloy Parts
Authors: Yavari Reza , Severson Jordan , Gaikwad Aniruddha , Cole Kevin , Rao Prahalad
Published: November 2019

The objective of this paper is to experimentally validate the graph-based approach that was advanced in our previous work for predicting the heat flux in metal additive manufactured parts. We realize this objective in the specific context of the directed energy deposition (DED) additive manufacturing process. Accordingly, titanium alloy (Ti6Al4V) test parts (cubes) measuring 12.7 mm × 12.7 mm × 12.7 mm were deposited using an Optomec hybrid DED system at the University of Nebraska-Lincoln (UNL). A total of six test parts were manufactured under varying process settings of laser power, material flow rate, layer thickness, scan velocity, and dwell time between layers. During the build, the temperature profiles for these test parts were acquired using a single thermocouple affixed to the substrate (also Ti6Al4V). The graph-based approach was tailored to mimic the experimental DED process conditions. The results indicate that the temperature trends predicted from the graph theoretic approach closely match the experimental data; the mean absolute percentage error between the experimental and predicted temperature trends were in the range of 6% ∼ 15%. This work thus lays the foundation for predicting distortion and the microstructure evolved in metal additive manufactured parts as a function of the heat flux. In our forthcoming research we will focus on validating the model in the context of the laser powder bed fusion process.
Fabrication of Glass to Metal Connections Using a Laser Heated Additive Approach
Authors: Curtis Bret , Lough Cody , Landers Robert , Bristow Doug , Kinzel Edward
Published: November 2019

Glass-to-metal seals are important in hermetic electrical feedthroughs for high-temperature and high-pressure applications. Traditionally, glass-to-metal seals are created using a high temperature furnace with controlled pressure and atmosphere. Current manufacturing techniques for glass-to-metal seals require precise fixturing (limiting unitization) and face restrictions in terms of the coefficient of thermal expansion for the glass/metal system. This paper explores the potential to use a laser to locally heat the glass as the first step toward the additive manufacturing of glass to metal seals. Studies are conducted fusing both frit and preforms under ambient conditions. The effects of process parameters on the process are quantified. The paper shows the potential of the process using Selective Laser Melting equipment, which can lead to greater flexibility for glass-to-metal seals with respect to geometry, materials, and spatially varying properties.
Pharmaceutical otoprotection strategies to prevent impulse noise-induced hearing loss
Authors: Bielefeld Eric C. , Harrison Ryan T. , Riley DeBacker J.
Published: November 2019

One of the ongoing challenges for hearing researchers is successful protection of the ear from noise injury. For decades, the most effective methods have been based on modifying the acoustic properties of the noise, either by reducing noise output from various sources, interfering in the acoustic exposure path with environmental controls, or altering the noise dose for the individual with personal hearing protection devices. Because of the inefficiencies of some of the acoustic modification procedures, pharmaceutical otoprotection is targeted at making the cochlea less susceptible to injury. Short-duration, high-level impulse noises, typically caused by small-scale explosions, cause different sets of injuries in the ear than long-duration, low-variance noise exposures. Therefore, the expectation is that the ears exposed to impulse noise may need different pharmaceutical interventions, both in type of compounds used and the time course of administration of the compounds. The current review discusses four different classes of compounds that have been tested as impulse noise otoprotectants. In the process of describing those experiments, particular emphasis is placed on the acoustic properties of the impulses used, with the goal of providing context for evaluating the relevance of these different models to human impulse noise-induced hearing loss.
Noise-dose estimated with and without pre-cochlear amplification
Authors: Grinn Sarah K. , Le Prell Colleen G.
Published: November 2019

Amplification from natural ear canal resonance has been documented as highly variable across individuals. However, individual variability in total pre-cochlear amplification (i.e., combined external and middle ear mechanisms) remains understudied in relevance to noise-induced hearing loss (NIHL). It is well-known that more noise means more risk of hearing loss, yet the current risk-models do not consider individually variable pre-cochlear amplification, also referred to as the transfer function of the open ear (TFOE). The present study principally documented individual TFOE variability and explored the feasibility and accuracy of simple proxy metrics, which could be used to estimate TFOE. Participants' TFOE values were used to estimate their NIHL risk in hypothetical free-field exposures. Forty-eight adult participants (42 female, 6 male, ages 21–60 years) met inclusion criteria of 2 healthy pinnae and ear canals (<10% cerumen occlusion) and type-A tympanometric examination. Participants underwent otoscopy, tympanometry, pinna size measurement, real-ear-to-coupler-difference, and TFOE measurement. TFOE ranged from 5 to 15 dB-A (mean = 10 dB-A); given that NIHL risk is estimated to double in either 3 or 5 dB-A increments, the observed variability could explain a substantial portion of individual vulnerability to NIHL. A simple regression model with eardrum compliance (ml) was correlated with individual TFOE (p < 0.05). TFOE variability has the potential to substantially explain why two individuals with the same noise-exposure can develop significantly different degrees of NIHL. Eardrum compliance (ml) was a correlated proxy measurement of TFOE in this principally adult, female dataset; additional research is needed to confirm this relationship in a unique, heterogeneous dataset.
The role of diet in vulnerability to noise-induced cochlear injury and hearing loss
Authors: Spankovich Christopher , Le Prell Colleen G.
Published: November 2019

The influence of dietary nutrient intake on the onset and trajectory of hearing loss during aging and in mediating protection from challenges such as noise is an important relationship yet to be fully appreciated. Dietary intake provides essential nutrients that support basic cellular processes related to influencing cellular stress response, immune response, cardiometabolic status, neural status, and psychological well-being. Dietary quality has been shown to alter risk for essentially all chronic health conditions including hearing loss and tinnitus. Evidence of nutrients with antioxidant, anti-inflammatory, and anti-ischemic properties, and overall healthy diet quality as otoprotective strategies are slowly accumulating, but many questions remain unanswered. In this article, the authors will discuss (1) animal models in nutritional research, (2) evidence of dietary nutrient-based otoprotection, and (3) consideration of confounds and limitations to nutrient and dietary study in hearing sciences. Given that there are some 60 physiologically essential nutrients, unraveling the intricate biochemistry and multitude of interactions among nutrients may ultimately prove infeasible; however, the wealth of available data suggesting healthy nutrient intake to be associated with improved hearing outcomes suggests the development of evidence-based guidance regarding diets that support healthy hearing may not require precise understanding of all possible interactions among variables. Clinical trials evaluating otoprotective benefits of nutrients should account for dietary quality, noise exposure history, and exercise habits as potential covariates that may influence the efficacy and effectiveness of test agents; pharmacokinetic measures are also encouraged.
Newly discovered variant of oesophageal atresia: ‘Type Y’
Authors: Fouad Dina , Macdonald Alexander , Bouhadiba Nordeen , Yardley Iain
Published: November 2019

Multiple variations of oesophageal atresia (OA) have been described. We present two cases of a new variant of OA (‘Type Y’) where the fistula enters the trachea in a Y-shaped configuration. Awareness of this is important. Bronchoscopy will reveal a single fistula opening and therefore there will initially be no suspicion of anatomical variation. It may be that only one bifurcation of the ‘Y’ fistula is patent which poses a risk of incomplete fistula closure.
Rhabdomyosarcoma involving maxilla mimicking gingival enlargement: A diagnostic challenge
Authors: Nangalia Richa , Shah Neha , Sheikh Mahmud Abdul , Pal Mousumi
Published: November 2019

Rhabdomyosarcoma (RMS) is a rare, rapidly growing, highly aggressive malignant neoplasm, originating from undifferentiated mesenchymal cells that retain their ability to differentiate into skeletal muscle. It mainly affects children, accounts for <1% of all adult malignancies and has varied clinical presentations. The head and neck region accounts for 35%–40% of all RMS cases, of which 10%–12% cases involve the oral cavity. This report deals with a case of RMS in a 40-year-old woman, primarily involving maxillary gingiva for which she underwent excision with subsequent recurrences. The uniqueness of this case is that it reminds us of the essential clinical dictum that ‘every growth we encounter, no matter how benign it appears clinically, should be looked upon with suspicion’. Hence, proper integration of history, clinical examination and investigation is required to reach a correct diagnosis enabling early treatment, thereby preventing functional and aesthetic loss and psychological trauma.
Associations of dairy intake with risk of mortality in women and men: three prospective cohort studies
Authors: Ding Ming , Li Jun , Qi Lu , Ellervik Christina , Zhang Xuehong , Manson JoAnn E , Stampfer Meir , Chavarro Jorge E , Rexrode Kathryn M , Kraft Peter , Chasman Daniel , Willett Walter C , Hu Frank B
Published: November 2019

Objective

To examine the association of consumption of dairy foods with risk of total and cause specific mortality in women and men.

Design

Three prospective cohort studies with repeated measures of diet and lifestyle factors.

Setting

Nurses’ Health Study, Nurses’ Health Study II, and the Health Professionals Follow-up Study, in the United States.

Participants

168 153 women and 49 602 men without cardiovascular disease or cancer at baseline.

Main outcome measure

Death confirmed by state vital records, the national death index, or reported by families and the postal system. During up to 32 years of follow-up, 51 438 deaths were documented, including 12 143 cardiovascular deaths and 15 120 cancer deaths. Multivariable analysis further adjusted for family history of cardiovascular disease and cancer, physical activity, overall dietary pattern (alternate healthy eating index 2010), total energy intake, smoking status, alcohol consumption, menopausal status (women only), and postmenopausal hormone use (women only).

Results

Compared to the lowest category of total dairy consumption (average 0.8 servings/day), the multivariate pooled hazard ratio for total mortality was 0.98 (95% confidence interval 0.96 to 1.01) for the second category of dairy consumption (average 1.5 servings/day), 1.00 (0.97 to 1.03) for the third (average 2.0 servings/day), 1.02 (0.99 to 1.05) for the fourth (average 2.8 servings/day), and 1.07 (1.04 to 1.10) for highest category (average 4.2 servings/day; P for trend <0.001). For the highest compared to the lowest category of total dairy consumption, the hazard ratio was 1.02 (0.95 to 1.08) for cardiovascular mortality and 1.05 (0.99 to 1.11) for cancer mortality. For subtypes of dairy products, whole milk intake was significantly associated with higher risks of total mortality (hazard ratio per 0.5 additional serving/day 1.11, 1.09 to 1.14), cardiovascular mortality (1.09, 1.03 to 1.15), and cancer mortality (1.11, 1.06 to 1.17). In food substitution analyses, consumption of nuts, legumes, or whole grains instead of dairy foods was associated with a lower mortality, whereas consumption of red and processed meat instead of dairy foods was associated with higher mortality.

Conclusion

These data from large cohorts do not support an inverse association between high amount of total dairy consumption and risk of mortality. The health effects of dairy could depend on the comparison foods used to replace dairy. Slightly higher cancer mortality was non-significantly associated with dairy consumption, but warrants further investigation.
Outcomes after peripheral artery disease intervention among Medicare–Medicaid dual-eligible patients compared with the general medicare population in the Vascular Quality Initiative registry
Authors: Austin Andrea M , Chakraborti Gouri , Columbo Jesse , Ramkumar Niveditta , Moore Kayla , Scheurich Michelle , Goodney Phil
Published: November 2019

Objective

To determine whether patients from the Vascular Quality Initiative (VQI) registry who are Medicare–Medicaid dual-eligible have outcomes after surgical intervention with medical devices such as stents for peripheral artery disease comparable to the outcomes of those eligible for Medicare alone.

Methods

The study cohort included fee-for-service Medicare beneficiaries from 2010 to 2015 who underwent peripheral vascular intervention as determined by the VQI. We performed propensity matching between the dual-eligible and non-dual-eligible cohorts. Postintervention use, including imaging, amputation and death, was determined using Medicare claims data.

Results

Rates of major amputation were higher among dual-eligible patients (13.0% vs 10.5%, p<0.001), while time to amputation by disease severity was similar (p=0.443). For patients with more advanced disease (critical limb ischaemia (CLI) vs claudication), dual-eligible patients have significantly faster times to any amputation and death (p<0.001). For of postoperative imaging, 48.4% of dual-eligible patients receive at least one postoperative image, while the percentage for non-dual-eligible patients is 47.2% (p=0.187).

Conclusions

Patients with mild forms of peripheral artery disease (PAD), such as claudication, demonstrated similar outcomes regardless of dual-eligibility status. However, those with severe PAD, such as CLI, who were also dual-eligible had both inferior overall survival and amputation-free survival. Minimal differences were observed in process-driven aspects of care between dual-eligible and non-dual-eligible patients, including postoperative imaging. These findings indicate that despite receiving similar care, dual-eligible patients with severe PAD have inferior long-term outcomes, suggesting the Medicaid safety net is not timely enough to benefit from long-term outcomes for these patients.
A comparison of waste leaching determination methods in the context of dewatered oil sands fine tailings
Authors: Utting N. , McMullen C. , Morin M. , Muñoz P.
Published: November 2019

Leaching tests are an important component in assessing the potential of contaminants to leach from waste materials to the environment. Numerous leaching test protocols have been developed for different applications. In this study, we compare four different methods in the context of assessing leaching of inorganic ions from oil sands tailings. The four methods compared were: United States Environmental Protection Agency (EPA) Toxicity Characteristic Leaching Procedure; ASTM D6234; ASTM D3987; and what we refer to as the Deionized method (modified from Syncrude Analytical Aqueous Extraction of Oil Sand Method 1.7). It was found that the EPA Toxicity Characteristic Leaching Procedure generally resulted in the highest ion concentrations. The EPA method had statistically different results for three of the four tailings mixes when compared with the other three leaching methods. For Mo and Ti the EPA method always resulted in the lowest concentrations compared with the other methods, and As, Tl, and Pb sometimes resulted in the lowest concentrations. The other three leaching protocols resulted in similar dissolved ion concentrations.