bluuebunny/crossref_metadata_2025 huggingface dataset:
Simple Method for DTS/DSS Data Interpretation: An Application to Pipeline Geotechnical Monitoring
Authors: Ravet Fabien , Chin Sanghoon , Briffod Fabien , Rochat Etienne
Published: November 2019

Geotechnical monitoring based on optical fiber sensor technology has been used over more than a decade to detect hazards than can affect the integrity of pipelines. In particular when these sensors are implemented in the form of distributed temperature and strain sensors, respectively known as DTS and DSS, they provide information about hazard location and spatial extension. In addition, these sensors can capture the speed at which the event developing in particular when implemented as a permanent monitoring solution. So far these sensors were implemented as part of an alarming system detecting events such as landslides, erosion and subsidence. The current work aims at presenting simple method to extract additional information about the hazard such as the amplitude of the soil displacement in the case of landslides and subsidence or dirt cover for erosion. Estimation of stress in soil is also discussed based on the cable strain-stress relation obtained from the sensing cable qualification. The approach is validated by academic works conducted in parallel of the technology development. The method use is then illustrated by its application to field data collected from several events occurred over the past 10 years.
Learnings About Geohazards in Cenit Pipeline Integrity Management
Authors: Motta Tierradentro Carlos , Aristizabal Ceballos Jaime , Chaves Agudelo Julian , Torres Castro Camilo Eliecer
Published: November 2019

About 20% of Cenit’s hydrocarbon transport infrastructure are located on mountainous terrain susceptible to effect of geohazards. There is an integrity management plan based on inspection, monitoring and mitigation activities; however, the occurrence of accidents triggered by geohazards has caused emergencies with effects on environment receiver and on operation of transport systems This paper presents, through management some of these accidents, good practices identified, learning in terms of prevention, preparation and response to emergencies and identification of priorities and gaps, in order to strengthen continuous improvement of the geohazards integrity management strategy.
Natural-Language Chat and Control HMI for Manufacturing Shopfloor
Authors: Zhiqiang Zhao , Varghese Aby , Quan Chua Wei , Ashok Prabhu Vinayak
Published: November 2019

The ability to instantly and successfully interact among technical engineers, management team and machines is vital to the productivity and efficiency of manufacturing shopfloor. Chat messenger with smart mobile has obvious advantages for shopfloor management in group communication, instant notification and remote control. This paper presents a natural-language chat & control HMI for manufacturing shopfloor. The system successfully realizes a smooth two-way communication between users and shopfloor machines. Users can access just-in-time information, receive instant notifications, and remotely control shopfloor machines. All relevant parties can communicate over shopfloor matters in a chat group. The system comprises of four core modules, i.e. Chat Messenger, Chat Service Engine, Control & Communication Engine and Local Command Service. Chat Messenger provides chatting user interface and group management dealing with end-user’s enquiries and notifications via natural language. Chat Service Engine and Control & Communication Engine are two cloud-based service modules, which process questionnaire logic and transmit relevant commands and data bi-directionally between Chat Messenger and Local Command Service. Local Command Service is a local service terminal which implements interfaces and protocols directly interacting with shopfloor machines. It processes the requests and commands from Chat Messenger to shopfloor machines. It also checks real-time machine anomalies and automatically generates corresponding notifications. The system has been implemented in the advanced manufacturing shopfloor at Nanyang Polytechnic. The results and validation show the improvement of manufacturing shopfloor efficiency.
Minimizing Energy Consumption and Line Length of Mixed-Model Multi-Robotic Disassembly Line Systems Using Multi-Objective Evolutionary Optimization
Authors: Fang Yilin , Wei Hongkai , Liu Quan , Li Yongliang , Zhou Zude , Pham Duc Truong
Published: November 2019

Robot helps to increase automation and economic benefits of disassembly line systems, and reduce risk to the human worker. For the robotic disassembly line, its energy consumption can be further optimized to reduce carbon dioxide emissions. In this paper, energy consumption of disassembly line systems is considered to be one of optimization objectives of disassembly line balancing problem. In the proposed model, the optimization objectives are to minimize the energy consumption and the line length (number of multi-robotic workstations and number of opened disassembly robots). To solve this multi-objective optimization problem, an improved NSGA-III optimization algorithm which consists of problem-dependent global and local variation operators is proposed. Several experiments are conducted to verify the effectiveness of the proposed method. In terms of hypervolume indicator, compared with three other state-of-art multi-objective evolutionary algorithms, the proposed method outperforms the best in small-scale, medium-scale, and large-scale problems. The proposed method also performs better on the problem of all scales than MOEA\D and NSGA-II in inverted generational distance metric, the proposed approach outperforms NSGA-III in most small-scale, some medium-scale and large-scale problems. The Friedman test based on the indicators of hypervolume and inverted generational distance is also conducted to verify the effectiveness of the proposed method.
A New Joint Data-Model Driven Dynamic Scheduling Architecture for Intelligent Workshop
Authors: Peng Kunkun , Li Xinyu , Gao Liang , Wang Xi (Vincent) , Gao Yiping
Published: November 2019

Intelligent manufacturing plays a significant role in Industry 4.0. Dynamic shop scheduling is a key problem and hot research topic in the intelligent manufacturing systems, which is NP-hard. However, traditional shop scheduling mode, dynamic event prediction approach, scheduling model and scheduling algorithm, cannot cope with increasingly complicated problems under kinds of scales production disruptions in the real-world production. To deal with these problems, this paper proposes a new joint data-model driven dynamic scheduling architecture for intelligent workshop. The architecture includes four new and key characteristics in the aspects of scheduling mode, dynamic event prediction, scheduling model and algorithm. More specifically, the new scheduling mode introduces data analytics methods to quickly and accurately deal with the dynamic events encountered in the production process. The new prediction model improves the deep learning method, and further applies it predict the dynamic events accurately to provide reliable input to the dynamic scheduling. The new scheduling model proposes a new hybrid rescheduling and inverse scheduling model, which can cope with almost scales of abnormal production problems. The new scheduling algorithm hybridizes dynamic programming and intelligent optimization algorithm, which can overcome the disadvantages of the two methods based on the analysis of solution space. The dynamic programming is employed to provide high-quality initial solutions for the intelligent optimization algorithm by reducing the computation time greatly. To sum up, the presented architecture is a new attempt to understand the problem domain knowledge and broaden the solving idea, which can also provide new theories and technologies to manufacturing system optimization and promote the applications of the theoretical results.
Study of Effect of Teeth Number on Cutting Force for Cutter Selection in the End Milling of TC4
Authors: Shi Kaining , Liu Ning , Wang Sibao , Ma Chi , Yang Bo , Yi Lili , Kang Ling
Published: November 2019

Cutting force is a very important factor in machining processes for predicting chatter, surface roughness and machining efficiency. For a given cutter, cutting force is determined by cutting force coefficients and uncut chip thickness. Once a new cutter is adopted, repeated experiments are carried out to calibrate its cutting force coefficients. To reduce the high cost and longtime experiments, theoretical analysis of the effect of cutter parameters on cutting force is required. In current literatures, some cutter parameters, such as helix angle and pitch angle, have been studied to explore their effects on cutting force. However, there is little research about the effect of teeth number on the cutting force. To fill up this gap, the effect of teeth number on cutting force is studied in the paper. Firstly, it is derived and experimentally verified that the cutting force coefficients are unchanged for cutters with different teeth number but the same teeth parameters, e.g., rake angle, shear angle, etc. Secondly, by matching the measured cutting force point with the cutter rotation angle, the cutting force coefficients can be calibrated by only one experiment when we assume that the material of the cutter is the same. Therefore, the cutting forces generated by cutters with different teeth numbers can be predicted based on only one experiment. Thirdly, from the various comparisons, it is concluded that cutter with 2 teeth number is suggested for side milling and cutter with 3 teeth number is suggested for slotting when surface roughness is considered. The cutter with 5 teeth number is suggested when only the machining efficiency is concerned. Finally, various experiments are carried out to verify the proposed study in milling of titanium alloy Ti6Al4V (TC4), and the comparison results show a good agreement.
Friction Torque and Leakage Based Data-Driven Approach for Rotary Seal Prognostics in Manufacturing Industry
Authors: Ramachandran Madhumitha , Siddique Zahed
Published: November 2019

Rotary seals are found in many manufacturing equipment and machines used for various applications under a wide range of operating conditions. Rotary seal failure can be catastrophic and can lead to costly downtime and large expenses; so it is extremely important to assess the degradation of rotary seal to avoid fatal breakdown of machineries. Physics-based rotary seal prognostics require direct estimation of different physical parameters to assess the degradation of seals. Data-driven prognostics utilizing sensor technology and computational capabilities can aid in the in-direct estimation of rotary seals’ running condition unlike the physics-based approach. An important aspect of data-driven prognostics is to collect appropriate data in order to reduce the cost and time associated with the data collection, storage and computation. Seals in machineries operate in harsh conditions, especially in the oil field, seals are exposed to harsh environment and aggressive fluids which gradually reduces the elastic modulus and hardness of seals, resulting in lower friction torque and excessive leakage. Therefore, in this study we implement a data-driven prognostics approach which utilizes friction torque and leakage signals along with Multilayer Perceptron as a classifier to compare the performance of the two metrics in classifying the running condition of rotary seals. Friction torque was found to have a better performance than leakage in terms of differentiating the running condition of rotary seals throughout its service life. Although this approach was designed for seals in oil and gas industry, this approach can be implemented in any manufacturing industry with similar applications.
Experimental Study on the Warpage and Tensile Strength of Additively Manufactured Semi-Crystalline Polyamide 6
Authors: Struebig Konstantin , Schröffer Andreas , Lueth Tim C.
Published: November 2019

Semi-crystalline polymers offer great mechanical properties and are ubiquitously found in everyday life. Despite of this, they are not yet widespread among additive manufacturing processes, due to their high tendency to warp. This leads to unstable build processes and dimensionally inaccurate parts, which greatly reduces their usability. This paper describes the findings of an experimental study designed to identify relevant parameters that affect the warpage and investigate the influence of the manufacturing method on the mechanical properties of semi-crystalline PA6.

The first experiment investigates the effect of water absorption over time, measuring weight and curling of 64 specimens over three weeks. The second part of this study focuses on the changes in geometry caused by the warpage by evaluating a basic model for simple part geometries. At last, a tension test was conducted and the results were compared to injection molded parts of the same material.

The results indicate, that while the absorption of water plays an important role in the warpage of hydrophilic polymers like PA6, other environmental factors also have a significant influence. The model evaluation showed, that the warpage geometry of the tested parts can be approximated with only three parameters for very simple parts, if there are no irregularities in the manufacturing process. The tensile tests revealed, that the additively manufactured specimens reach up to 85.9% of the strength of the injection molded reference parts, most likely due to imperfect filling and reduced density.

Overall, this study provides an insight into the challenges of additively manufacturing semi-crystalline polymers and the potential of PA6 as a tougher alternative to the common materials.
Magnetorheological Nano-Surface-Finishing of Tapered Cavity of Chrome Steel Punch
Authors: Thomas Arpit , Singh Anant Kumar
Published: November 2019

The need for finishing chrome steel punch has drastically increased in order to obtain products with high quality and productivity. Chrome steel finds its application in manufacturing of punch and dies because of its higher hardness as varies up to 62 HRC. The paper is focused on improving the productivity of chrome steel punch through improving the surface finish using magnetorheological finishing process with a solid rotating tool core. The traditional method used for finishing of the chrome steel punch involves diamond lapping where machining marks and surface micro cracks are observed. In punching operation, the punch undergoes adhesive wear which can be controlled if the surface finish of the punch is improved. The surface finish obtained after diamond lapping process is up to 408 nm range. In present work, the further finishing of the tapered cavity of chrome steel punch is carried out. The chrome steel punch workpiece is rotated in a direction opposite to the rotation of the tapered tool tip surface in order to efficiently perform the finishing operation. The final surface roughness value of the flat surface of circular tapered punch is obtained as 26 nm from 420nm while the roughness value of the tapered surface is obtained as 22 nm from 408 nm in 90 minutes of finishing.
Improving Room Temperature-Stretch Formability of Magnesium Alloys by Laser Shock Peening
Authors: Mao Bo , Zhang Xing , Liao Yiliang , Li Bin
Published: November 2019

The applications of magnesium (Mg) and their alloys are often restricted by their poor formability at room temperature. Several strategies have been developed in recent years to enhance the formability of Mg alloys, such as grain refinement and texture weakening, either by alloying or processing. Laser shock peening (LSP) is an advanced laser-based surface processing method which has been utilized improve the surface hardness, fatigue performance, and corrosion resistance of Mg alloys. Recent studies show that LSP can bring significant texture weakening and grain refinement effect in Mg alloy, indicating its potential capability of enhancing the formability of Mg alloys. This research is to explore the applicability of LSP to improve the room temperature-stretch formability of Mg alloys. LSP experiments are carried out on an AZ31B Mg alloys. The microstructure before and after LSP are characterized by optical microscopy (OM) and electron backscattered diffraction (EBSD) microscopy. Erichsen tests are carried out to evaluate the stretch formability of Mg alloys. The results show that LSP can bring texture weakening and grain refinement effect simultaneously, resulting in the improved room temperature-stretch formability of Mg alloys.
Effects Analysis of Internal Buffers in Serial Manufacturing Systems for Optimal Throughput
Authors: Imseitif Jad , Tang Herman
Published: November 2019

Buffers can improve the efficiency of manufacturing systems by accommodating the negative impacts of machine stoppage and maximize the system throughput. Buffers are often designed and integrated into manufacturing systems.

This study investigates the effects of small internal buffers on the throughput of serial manufacturing systems using discrete-event simulation (DES). For a serial manufacturing system, its internal buffer can be designed as an idle station or a small conveyor. In the study, typical automotive assembly lines are used as serial manufacturing systems. In addition, the capacity of a small internal buffer and two small buffers are studied for optimal throughput. The study results provide a general approach on where to assign small internal buffers in serial manufacturing systems and what the effects of such buffers and their configurations are.
Phase Diagram of Pinch-Off Behaviors During Drop-on-Demand Inkjetting of Alginate Solutions
Authors: Xu Changxue , Zhang Zhengyi , Huang Yong , Xu Heqi
Published: November 2019

Viscoelastic polymer solutions have been extensively utilized in drop-wise manufacturing (such as inkjet printing) for a variety of biomedical applications. The pinch-off of viscoelastic jets is a key step towards generation of droplets in inkjet printing. This complex process is governed by interplay of four stresses including inertial stress, capillary stress, viscous stress, and elastic stress. Depending on polymer solution properties and process conditions, four types of pinch-off phenomenon were observed during inkjetting of viscoelastic alginate solutions. In this study, material properties of alginate solutions with different concentrations have been characterized, and three dimensionless numbers (Ohnesorge number Oh, Deborah number De and Weber number We) have been proposed to analyze different pinch-off behaviors. Phase diagram in terms of these three dimensionless numbers has been constructed to classify the regimes for different pinch-off types during inkjetting of viscoelastic alginate solutions. It is found that: 1) At low De and Oh, the viscoelastic effect is small. The capillary stress is mainly balanced by the inertial stress, resulting in front pinching. 2) At medium De and low Oh, the capillary stress is still mainly balanced by the inertial stress, but the elastic effect starts to show its effect by delaying the ligament thinning near the front-pinching location. With the increase of We, the pinch-off type may change from front pinching to hybrid pinching to exit pinching. 3) At low Oh and high De, the viscous and inertial effects are small. The capillary stress is mainly balanced by the elastic stress, resulting in exit pinching. 4) At high Oh and De, the viscoelastic effect is dominant. The capillary stress is mainly balanced by the viscous and elastic stresses. With the increase of We, middle pinching turns to be exit pinching due to the increase of the initial ligament diameter near the forming droplet.
Where Do We Start? Guidance for Technology Implementation in Maintenance Management for Manufacturing
Authors: Brundage Michael P. , Sexton Thurston , Hodkiewicz Melinda , Morris KC , Arinez Jorge , Ameri Farhad , Ni Jun , Xiao Guoxian
Published: November 2019

Recent efforts in Smart Manufacturing (SM) have proven quite effective at elucidating system behavior using sensing systems, communications and computational platforms, along with statistical methods to collect and analyze real-time performance data. However, how do you effectively select where and when to implement these technology solutions within manufacturing operations? Furthermore, how do you account for the human-driven activities in manufacturing when inserting new technologies? Due to a reliance on human problem solving skills, today’s maintenance operations are largely manual processes without wide-spread automation. The current state-of-the-art maintenance management systems and out-of-the-box solutions do not directly provide necessary synergy between human and technology, and many paradigms ultimately keep the human and digital knowledge systems separate. Decision makers are using one or the other on a case-by-case basis, causing both human and machine to cannibalize each other’s function, leaving both disadvantaged despite ultimately having common goals.

A new paradigm can be achieved through a hybridized systems approach — where human intelligence is effectively augmented with sensing technology and decision support tools, including analytics, diagnostics, or prognostic tools. While these tools promise more efficient, cost-effective maintenance decisions, and improved system productivity, their use is hindered when it is unclear what core organizational or cultural problems they are being implemented to solve. To explicitly frame our discussion about implementation of new technologies in maintenance management around these problems, we adopt well established error mitigation frameworks from human factors experts — who have promoted human-systems integration for decades — to maintenance in manufacturing. Our resulting tiered mitigation strategy guides where and how to insert SM technologies into a human-dominated maintenance management process.
Binder Jetting Additive Manufacturing of Ceramics: Analytical and Numerical Models for Powder Spreading Process
Authors: Miao Guanxiong , Du Wenchao , Pei Zhijian , Ma Chao
Published: November 2019

Binder jetting additive manufacturing is a promising way to process ceramic materials which are hard to be manufactured into complex shapes using conventional methods. However, the application of binder jetting is limited by the relatively low density of manufactured parts. Powder bed forming process is a critical step that determines the powder bed density and consequently the part density. Thus, investigating and understanding the power spreading process is necessary to improve the part density. A numerical model is developed to predict the powder bed density under different spreading conditions using the discrete element method (DEM). The predicted DEM results are compared with the prediction of an analytical model. The results show that under different layer thicknesses (50 μm, 70 μm, 100 μm) and roller diameters (12 mm, 14 mm, and 16 mm), the predicted maximum powder bed density by these two models has nearly the same value and the predicted maximum packing stress has the same trend.
Performance Metrics for Product Flow Configuration in a Reconfigurable Manufacturing System (RMS)
Authors: Singh Prince Pal , Madan Jatinder , Singh Harwinder
Published: November 2019

We propose a systematic approach for product flow configuration selection for reconfigurable manufacturing system (RMS) that considers ten industrially relevant most important factors. The paper first defines performance metrics for the identified factors. A composite performance metric (CPM) has been proposed, which accounts for all ten-performance metrics to assess the performance of RMS with the help of a combined score. The methodology of developing CPM applies analytical hierarchy process (AHP) approach where weightage to each of the performance metric is also considered. To showcase the usefulness and feasibility of the CPM, it has been applied in an industrial environment with the help of an industrial case study. Both the CPM and other metric scores were found to be quite useful to identify a suitable configuration out of the available alternatives.
Mechanical Finishing of 3D Printed Continuous Carbon Fiber Reinforced Polymer Composites via CNC Machining
Authors: Parandoush Pedram , Deines Timothy , Lin Dong , Zhang Hao , Ye Chang
Published: November 2019

3D printing technology could be extremely beneficial for increasing the flexibly and reducing the cost of carbon fiber reinforced polymer composite (CFRP) production. However, this technology suffers from poor surface quality and uncertain engineering quality. Mechanical finishing processes could concurrently solve these surface issues with the 3D printed composites components. Herein, a mechanical finishing process for 3D printed CFRP composites via CNC milling is proposed to improve the surface quality of two 3D printing methods, namely fused deposition modeling (FDM) and laser assisted-laminated object manufacturing (LA-LOM). The 3D printed CFRP structures fabricated via both methods comprise of continuous carbon fiber reinforcement. The surface roughness and surface morphology of the original unfinished and finished surfaces with various cutting depths are extensively studied to investigate the feasibility of the proposed finishing technique. The surface morphology of the surfaces parallel and perpendicular to the 3D printed layers is the main focus of this work. After the CNC finishing process, the surface roughness of the 3D printed CFRP composites is improved by 70% and 60% for FDM and LA-LOM components, respectively. A smooth, consistent, and predictable surface morphology is achieved for various cutting depths demonstrating a substantial improvement over the original 3D printed surfaces.
Study on Formation and Performance of Electric-Aided Self-Piercing Riveted Aluminum Alloy and Dual-Phase Steels With Different Strength Grades
Authors: Lou Ming , Ma Yunwu , Li Yongbing
Published: November 2019

To improve the joint quality by reducing the deformation resistance of dual-phase (DP) steels, electric-aided self-piercing riveting (EA-SPR) was conducted in this paper. The effect of current density on the joint forming process, geometry characteristics and mechanical properties of EA-SPR for both combinations of aluminum to steel and steel to aluminum were investigated and compared with the traditional SPR joints. It was found that the riveting force decreased for all the DP steels with different strength grades. The increase amplitude of undercut increased with the elevated strength grades of DP steels. When riveting from aluminum to steel, the tensile-shear and cross-tension strengths of EA-SPR joints could improve up to 13.3% and 15.7% respectively, compared with the traditional SPR joints. For joints riveted from steel to aluminum, the current showed less effect on the tensile-shear strength due to the rivet shank fracture. Nevertheless, the cross-tension strength could still improve by 13.04%.
Laser Deposition-Additive Manufacturing of Graphene Oxide Reinforced IN718 Alloys: Effects on Surface Quality, Microstructure, and Mechanical Properties
Authors: Hu Yingbin , Wang Hui , Cong Weilong
Published: November 2019

Owing to its high stiffness and strength, low density, and excellent flexibility, nano-sized graphene oxide (GO) is considered as a competitive material to reinforce metallic materials. Conventional manufacturing methods for GO reinforced metal matrix fabrication include casting and powder metallurgy, both of which demonstrate disadvantages of high reinforcement agglomeration, high cost, and difficulty in fabrication of complex structures. To reduce these problems, it is important to investigate a finely-controlled, cost-saving, and near-net-shaping process for GO reinforced metal matrix manufacturing. Laser additive manufacturing is such a process that mainly includes selective laser sintering / melting (SLS / M) and laser deposition-additive manufacturing (LD-AM). Compared with SLS / M, LD-AM demonstrates parts remanufacturing capability and is capable of fabricating functionally gradient materials. In this investigation, GO reinforced Inconel 718 (IN718) parts, for the first time, are fabricated using LD-AM processes. The effects of GO on flatness, surface roughness, microstructure, microhardness, and wear resistance of LD-AM fabricated GO reinforced IN718 parts are studied. Experimental results show that the introduction of GO is beneficial for enhancing both microhardness and wear resistance but harmful to surface quality of fabricated parts. In addition, the presence of GO has little influence on microstructures.
A Numerical Study on the Keyhole Formation During Laser Powder Bed Fusion Process
Authors: Shrestha Subin , Chou Y. Kevin
Published: November 2019

The dynamic phenomenon of a melt pool during the laser powder bed fusion (LPBF) process is complex and sensitive to process parameters. As the energy density input exceeds a certain threshold, a huge vapor depression may form, known as the keyhole. This study focuses on understanding the keyhole behavior and related pore formation during the LPBF process through numerical analysis. For this purpose, a thermo-fluid model with discrete powder particles is developed. The powder distribution, obtained from a discrete element method (DEM), is incorporated into the computational domain to develop a 3D process physics model using FLOW-3D. The melt pool formation during the conduction mode and the keyhole mode of melting has been discerned and explained. The high energy density leads to the formation of a vapor column and consequently pores under the laser scan track. Further, the keyhole shape resulted from different laser powers and scan speeds is investigated. The numerical results indicated that the keyhole size increases with the increase in the laser power even with the same energy density. The keyhole becomes stable at a higher power, which may reduce the occurrence of pores during laser scanning.
Powder-Scale Meshfree Simulations of Powder Bed Fusion Based Additive Manufacturing Processes
Authors: Fan Zongyue , Wang Hao , Li Bo
Published: November 2019

We present a powder-scale meshfree direct numerical simulation (DNS) capability for the powder bed fusion (PBF) based additive manufacturing (AM) processes using the novel Hot Optimal Transportation Meshfree (HOTM) method. The HOTM method is an incremental Lagrangian meshfree computational framework for materials behaviors under extreme thermomechanical loading conditions, which combines the Optimal Transportation Meshfree (OTM) method and the variational thermomechanical constitutive updates. The realistic multi-layer powder bed geometry is modeled explicitly in the HOTM simulations based on experimental data. A phase-aware constitutive model is developed to predict the phase change and multiphase mixing during the PBF AM processes automatically. The governing equations including the linear momentum and energy conservation equations are solved for the multiphase flow simultaneously to predict the deformation, temperature and local state of the powder particles. The powder-scale DNS is employed to study the influence of various laser powers on the melt pool thermodynamics.
A State-of-the-Art Review on Aerosol Jet Printing (AJP) Additive Manufacturing Process
Authors: Salary Roozbeh Ross , Lombardi Jack P. , Weerawarne Darshana L. , Rao Prahalad K. , Poliks Mark D.
Published: November 2019

The goal of this work is to forward a comprehensive framework, relating to the most recent research works carried out in the area of flexible and hybrid electronics (FHE) fabrication with the aid of aerosol jet printing (AJP) additive manufacturing process. In pursuit of this goal, the objective is to review and classify a wide range of articles, published recently, concerning various aspects of AJP-based device fabrication, such as material synthesis, process monitoring, and control.

AJP has recently emerged as the technique of choice for integration as well as fabrication of a broad spectrum of electronic components and devices, e.g., interconnects, sensors, transistors, optical waveguides, quantum dot arrays, photodetectors, and circuits. This is preeminently because of advantages engendered by AJP process. AJP not only allows for high-resolution deposition of microstructures, but also accommodates a wide renege of ink viscosity. However, AJP is intrinsically complex and prone to gradual drifts of the process output (stemming from ink chemistry and formulation). Consequently, a large number of research works in the literature has focused on in situ process characterization, real-time monitoring, and closed-loop control with the aim to make AJP a rapid, reliable, and robust additive manufacturing method for the manufacture of flexible and hybrid electronic devices. It is expected that the market for flexible electronics will be worth over $50 billion by 2020 [1].
Computational Foundations for Using Three Degrees of Freedom Build Platforms to Enable Supportless Extrusion-Based Additive Manufacturing
Authors: Bhatt Prahar M. , Malhan Rishi K. , Gupta Satyandra K.
Published: November 2019

Extrusion-based additive manufacturing systems usually use three degrees of freedom extrusion tools to perform the deposition operation. This requires the use of support structures to deposit structures with overhang features. The use of support structures can be avoided by adding degrees of freedom to the build platform. The elimination of build structures can offer benefits in terms of reduction of build time and elimination of postprocessing costs. This paper demonstrates that the use of three degrees of freedom build platform enables printing of complex shapes without support structures. We present computational foundations for generating paths and trajectories for synchronizing the motion of three degrees of freedom build platforms and three degrees of freedom extrusion tools. We report results on six different test parts in terms of reduction in build time, accuracy, and surface roughness.
Dissecting
erm
(41)-Mediated Macrolide-Inducible Resistance in Mycobacterium abscessus
Authors: Richard Matthias , Gutiérrez Ana Victoria , Kremer Laurent
Published: November 2019

Macrolides are the cornerstone of
Mycobacterium abscessus
multidrug therapy, despite that most patients respond poorly to this class of antibiotics due to the inducible resistance phenotype that occurs during drug treatment. This mechanism is driven by the macrolide-inducible ribosomal methylase encoded by
erm
(41), whose expression is activated by the transcriptional regulator WhiB7.
Electronic Cigarette (E-Cigarette) Vapor Exposure Alters the Streptococcus pneumoniae Transcriptome in a Nicotine-Dependent Manner without Affecting Pneumococcal Virulence
Authors: Bagale Kamal , Paudel Santosh , Cagle Hayden , Sigel Erin , Kulkarni Ritwij
Published: November 2019

With the increasing popularity of e-cigarettes among cigarette smoking and nonsmoking adults and children and the recent reports of vaping-related lung illness and deaths, further analysis of the adverse health effects of e-cigarette vapor (EV) exposure is warranted. Since pathogenic bacteria such as
Streptococcus pneumoniae
can colonize the human nasopharynx as commensals, they may be affected by exposure to bioactive chemicals in EV. Hence, in this study we examined the effects of EV exposure on the physiology of
S. pneumoniae
strain TIGR4. In order to differentiate between the effects of nicotine and nonnicotine components, we specifically compared the RNA-Seq profiles and virulence of TIGR4 exposed to vapor from nicotine-containing and nicotine-free e-liquid formulations. We observed that nicotine-containing EV augmented TIGR4 biofilms and altered expression of TIGR4 genes predominantly involved in metabolism and stress response. However, neither nicotine-containing nor nicotine-free EV affected TIGR4 virulence in a mouse model.
Escherichia hermanniias the sole cause of osteomyelitis in a patient with an open tibial shaft fracture
Authors: Compton Jocelyn , Wynn Malynda , Willey Michael C , Sekar Poorani
Published: November 2019

Escherichia hermanniiis a rare monomicrobial cause of infection in humans.E. hermanniihas never before been reported as the sole isolate from an infected open tibia fracture. We present a case ofE. hermanniiinfection after a type III open tibia fracture. The patient was initially treated with irrigation and debridement, open reduction internal fixation and primary wound closure. However, after 8 weeks, he developed a draining wound and infection at the fracture site. He required a repeat debridement, hardware removal, external fixation and 6 weeks of intravenous ceftriaxone for treatment. At 2-year follow-up, he remains infection free, asymptomatic and continues to work with excellent functional outcomes. This case adds to the growing literature that evidencesE. hermanniias an organism that can be pathogenic, virulent and cause monomicrobial infection.
Development of pyogenic granuloma with strong vascular endothelial growth factor receptor-2 expression during ramucirumab treatment
Authors: Ibe Tatsuya , Hamamoto Yoichiro , Takabatake Mikage , Kamoshida Shingo
Published: November 2019

The angiogenesis inhibitor ramucirumab (IMC-1121B) is a fully humanised IgG1 monoclonal antibody targeting the extracellular domain of vascular endothelial growth factor receptor 2. Ramucirumab has been approved as a second-line treatment for lung cancer. Pyogenic granuloma is an acquired, benign vascular tumour of the skin or mucous membrane. We encountered a patient with pyogenic granuloma who was treated with ramucirumab. The patient was a 48-year-old Japanese woman with advanced lung cancer who had been heavily pretreated using several lines of chemotherapy. Ramucirumab was administered as the fifth-line treatment with docetaxel. After 10 days, a painless rice-coloured or pink papule appeared on her finger. One month later, it increased in size to 20 mm. We examined the pathological condition by immunostaining using the resected specimen diagnosed as pyogenic granuloma. Paradoxically, this vascular tumour arose during the administration of an angiogenesis inhibitor.
Intracranial invasive mycosis mimicking hepatic encephalopathy in a patient with cirrhosis
Authors: Roy Akash , Verma Nipun , Ahuja Chirag Kamal
Published: November 2019

A 45-year-old man with alcohol-related decompensated cirrhosis presented with jaundice, fever, headache and altered sensorium. At presentation, he had tachycardia, disorientation to time and place, asterixis, icterus and upgoing plantar response. Investigations showed anaemia, thrombocytopenia, leucocytosis, hyperbilirubinemia and elevated arterial ammonia. Despite management with antihepatic coma measures and normalisation of ammonia, broad-spectrum antibiotics, 20% albumin, the patient worsened. On day 3, the patient developed generalised tonic–clonic seizure prompting mechanical ventilation. Examination showed right proptosis, chemosis and pupillary anisocoria. MRI brain showed multifocal infarcts in the right temporal lobe, right cerebellum and brainstem with inflammation in the right orbit, infratemporal fossa with right internal carotid artery thrombosis, and suspicious maxillary sinus thickening. Nasal scrapings showed aseptate fungal hyphae and serum galactomannan index was positive. Despite receiving liposomal amphotericin-B, patient had an unfavourable outcome. Intracranial invasive mycosis can mimic hepatic encephalopathy and is associated with high mortality in cirrhotics. A high index of suspicion, positive biomarkers and diagnostic radiology may provide the key to the diagnosis.
Synovial sarcoma mimicking a traumatic pseudoaneurysm in the upper extremity
Authors: Wang Judy , Kok Hong Kuan , Bayat Iman
Published: November 2019

Synovial sarcomas are a rare but aggressive malignancy that primarily affects young patients. Diagnosis is often difficult and delayed due to its insidious onset, heterogenous presentation and mimicry of other pathologies. We present the case of a patient with a history of a slow-growing left arm mass that arose after a traumatic fracture of the humerus. Multimodal imaging was undertaken and reported the mass as being consistent with a vascular malformation of the brachial artery. The patient underwent surgical repair of the artery and intraoperative biopsies confirmed a diagnosis of synovial sarcoma. This case highlights the importance of maintaining suspicion for soft-tissue sarcomas in young patients presenting with a mass, and demonstrates the way in which these tumours may mimic other pathologies both clinically and radiologically. Early referral to a specialist sarcoma centre is key for further investigative workup.
Implementation of research evidence in orthopaedics: a tale of three trials
Authors: Reeves Katharine , Chan Samuel , Marsh Alastair , Gallier Suzy , Wigley Catrin , Khunti Kamlesh , Lilford Richard J
Published: November 2019

Objective

To examine implementation of evidence in orthopaedic practice following publication of the results of three pivotal clinical trials.

Design

Case studies based on three orthopaedic trials funded in sequence by the National Institute for Health Research Health Technology Assessment (HTA) programme. These trials dealt with treatment of fractures of the humerus, radius and ankle, respectively. For each case study, we conducted time-series analyses to examine the relationship between publication of findings and the implementation (or not) of the findings.

Results

The results of all three trials favoured the less expensive and less invasive option. In two cases, a change of practice, in line with the evidence that eventually emerged, preceded publication. Furthermore, the upturn in use of the intervention most supported by each of these two trials corresponded to the start of recruitment to the respective trial. The remaining trial failed to influence practice despite yielding clear-cut evidence.

Conclusions

Implementation of results of all three HTA orthopaedic trials favoured the less expensive and less invasive option. In two of the three studies, a change in practice, in line with the evidence that eventually emerged, preceded publication of that evidence. A trend or a change in practice, at around the start of the trial, indicates that the direction of causation opposes our hypothesis that publication of trial findings would lead to changes in practice. Our results provide provocative insight into the nuanced topic of research and practice, but further qualitative work is needed to fully explain what led to the pre-emptive change in practice we observed and why there was no change in the third case.
Improving access to contraception through integration of family planning services into a multidrug-resistant tuberculosis treatment programme
Authors: Cornish Emily F , Hudson Jonathan , Sayers Ross , Loveday Marian
Published: November 2019

Objectives

Multidrug-resistant tuberculosis (MDR-TB) is a global public health priority. The advent of the World Health Organisation’s Short Course regimen for MDR-TB, which halves treatment duration, has transformed outcomes and treatment acceptability for affected patients. Bedaquiline, a cornerstone of the Short Course regimen, has unknown teratogenicity and the WHO therefore recommends reliable contraception for all female MDR-TB patients in order to secure eligibility for bedaquiline. We were concerned that low contraceptive uptake among female patients in our rural South African MDR-TB treatment programme could jeopardise their access to bedaquiline. We therefore conducted a service delivery improvement project that aimed to audit contraceptive use in female MDR-TB patients, integrate family planning services into MDR-TB care, and increase the proportion of female patients eligible for bedaquiline therapy.

Methods

Contraceptive use and pregnancy rates were audited in all female patients aged 13–50 years initiated on our MDR-TB treatment programme in 2016. We then implemented an intervention consisting of procurement of depot-medroxyprogesterone acetate (DMPA) for the MDR-TB unit and training of specialist MDR-TB nurses in administration of DMPA. The audit cycle was repeated for all female patients aged 13–50 years initiated on the programme in January–October 2017 (post-intervention).

Results

The proportion of women on injectable contraceptives by the time of MDR-TB treatment initiation increased significantly in the post-intervention cohort (77.4% vs 23.9%, p<0.0001).

Conclusion

By integrating contraceptive services into our MDR-TB programme we significantly increased contraceptive uptake, protecting women from the obstetric risks associated with pregnancy during MDR-TB treatment and maximising their eligibility for bedaquiline therapy.
A novel self-expanding primarily bioabsorbable braided flow-diverting stent for aneurysms: initial safety results
Authors: Jamshidi Mehdi , Rajabian Mahmoud , Avery Michael B , Sundararaj Uttandaraman , Ronsky Janet , Belanger Brooke , Wong John H , Mitha Alim P
Published: November 2019

Introduction

The advent of metal flow-diverting stents has provided neurointerventionalists with an option for treating aneurysms without requiring manipulations within the aneurysm sac. The large amount of metal in these stents, however, can lead to early and late thrombotic complications, and thus requires long-term antiplatelet agents. Bioabsorbable stents have been postulated to mitigate the risk of these complications. Here we present early data on the first self-expandable primarily bioabsorbable stent for aneurysms.

Methods

Braided stents were developed using poly-L-lactic acid fibers with material surface area similar to metal flow diverters. Crush resistance force, hemolysis, and thrombogenicity were determined and compared with existing commercial devices. Stents were deployed in infra-renal rabbit aortas to determine angiographic side branch patency and to study neointima formation for a 1-month follow-up period.

Results

Crush resistance force was determined to be on the order of existing commercial devices. Hemolytic behavior was similar to existing metal devices, and thrombogenicity was lower than metal flow-diverting stents. A smooth neointimal layer was found over the absorbable stent surface and all covered side branches were patent at follow-up.

Conclusion

The design of self-expanding primarily bioabsorbable flow-diverting stents is possible, and preliminary safety data is consistent with a favorable profile in terms of mechanical behavior, hemocompatibility, side branch patency, and histological effects. Additional in vitro and long-term in vivo studies are in progress and will help determine aneurysm occlusion rates and absorption characteristics of the stent.
Lund jet images from generative and cycle-consistent adversarial networks
Authors: Carrazza Stefano , Dreyer Frédéric A.
Published: November 2019

We introduce a generative model to simulate radiation patterns within a jet using the Lund jet plane. We show that using an appropriate neural network architecture with a stochastic generation of images, it is possible to construct a generative model which retrieves the underlying two-dimensional distribution to within a few percent. We compare our model with several alternative state-of-the-art generative techniques. Finally, we show how a mapping can be created between different categories of jets, and use this method to retroactively change simulation settings or the underlying process on an existing sample. These results provide a framework for significantly reducing simulation times through fast inference of the neural network as well as for data augmentation of physical measurements.