bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic Resonance in an Axial Multistage Compressor Leading to Non-Synchronous Blade Vibration
Authors: Fiquet Anne-Lise , Vercoutter Agathe , Buffaz Nicolas , Aubert Stéphane , Brandstetter Christoph
Published: January 2021

Significant non-synchronous blade vibrations (NSV) have been observed in an experimental three-stage high-speed compressor at part-speed conditions. High amplitude acoustic modes, propagating around the circumference and originating in the highly loaded Stage-3 have been observed in coherence with the structural vibration mode.

In order to understand the occurring phenomena, a detailed numerical study has been carried out to reproduce the mechanism. Unsteady full annulus RANS simulations of the whole setup have been performed using the solver elsA. The results revealed the development of propagating acoustic modes which are partially trapped in the annulus and are in resonance with an aerodynamic disturbance in Rotor-3. The aerodynamic disturbance is identified as an unsteady separation of the blade boundary layer in Rotor-3. The results indicate that the frequency and phase of the separation adapt to match those of the acoustic wave, and are therefore governed by acoustic propagation conditions.

Furthermore, the simulations clearly show the modulation of the propagating wave with the rotor blades, leading to a change of circumferential wave numbers while passing the blade row. To analyze if the effect is self-induced by the blade vibration, a noncoherent structural mode has been imposed in the simulations. Even at high vibration amplitude the formerly observed acoustic mode did not change its circumferential wave number.

This phenomenon is highly relevant to modern compressor designs, since the appearance of the axially propagating acoustic waves can excite blade vibrations if they coincide with a structural eigenmode, as observed in the presented experiments.
An Artificial Intelligence Based Method for Performance Prediction and Inverse Design of Hydraulic Turbochargers
Authors: Thatte Azam , Vurimi Ganesh , Borate Prabhav , Javaherchi Teymour
Published: January 2021

A neural network based method is developed that can learn the underlying physics of hydraulic turbocharger (a radial pump coupled with a radial turbine) from a set of sparse experimental data and can predict the performance of a new turbocharger design for any given set of previously unseen operating conditions and geometric parameters. The novelty of the algorithm is that it learns the underlying physical mechanisms from a very sparse data spanning a broad range of flow rates and geometrical size brackets and uses these deeper common features recognized through a “mass-learning process” to predict the full performance curves for any given single geometry. The deep learning algorithm is able to accurately predict the key performance parameters like total efficiency of the turbocharger, its operating speed, pressure rise provided by the radial pump of the turbocharger and the shaft power produced by the radial turbine of the turbocharger for any given input combination of pump and turbine flow rates, differential pressure across the turbine and a limited set of geometrical parameters of pump and turbine impellers and volutes. Lastly, a novel method for fast inverse design of turbomachinery using a physics trained neural network and a constrained optimization algorithms is developed. The algorithm uses Nelder-Mead and Interior Point methods to find the global minimum of turbocharger design objective function in multi-dimensional space. The newly developed method is found to be very efficient in optimizing turbomachinery design problems with both equality and inequality constraints. The inverse design algorithm is able to successfully recommend an optimal combination of geometrical parameters like pump blade exit angle, pump impeller diameter, blade width, eye diameter, turbine nozzle diameter and rotational speed for a given target efficiency and head rise requirements. The preliminary results from this study indicate that it has a great potential to minimize the need for expensive 3D CFD based methods for the design of turbomachinery.
Interactive Learning Platform for Turbine Design Using Reduced Order Methods
Authors: Oliveira Igor , Silva George Patton , Tonon Daniel , Bringhenti Cleverson , Takachi Tomita Jesuíno
Published: January 2021

This work presents the implementation of an interactive learning platform for turbine design in an engineering teaching environment. Due to the abundance of strategies and problems encountered in a multidisciplinary iterative design process, presenting the student to the multitude of scenarios can be a laborious and time-consuming task, often not possible in one-semester courses for undergraduate students.

The developed computational program breaks down the preliminary design methodology into a step-by-step analysis of a single-stage axial turbine for aeronautical application. In it, the student is guided through velocity diagram construction, performance prediction, tridimensional and compressible effects considerations, blade designing as well as accounting for losses. In this interactive learning tool, it is possible to explore the sensitivity and effects of each design choice at various design steps, generating insight and hopefully a more intimate understanding.

This exploration generates real-time changes in the output interface, for example the velocity diagrams and major geometrical features, in which the student is able through different trials to observe and compare the impact of different approaches, choices and assumptions.

The program is written in Python language and the loss models chosen were Kacker and Okapuu; Dunham and Came; and Ainley and Mathieson. As the same set of design requirements can lead to different — yet optimal — configurations, the student will be given guidelines based on established design methodologies with the aid of graphs and the usual ranges of the calculated parameters found in practice.

At the end of this process, the student is able to harvest a final design from which it is possible to generate discussions among a class or examine the suitability of a final product in regards to a proposed assignment, objective or application.
The Design Analysis of the Damaged Compressor Blade Impact on the Aerodynamic Parameters
Authors: Fedechkin Konstantin S. , Kuzmin Maxim V. , Marchukov Evgeni U.
Published: January 2021

The research is about the traditional approach in defects assessment, like damages in aviation engine blades and problems in their further use based on the defects analysis not in one blade or stage but in the multistage compressor as a whole. When an airplane is in operation there can be incidents: birds in flight and a small stones and different metal object on the ground. When they penetrate into the engine, the fan’s blades are damaged. The software that simulates geometry model of blade damages has been developed. The calculation model of the damaged blade has been developed on the basis of real engine compressors. The calculation model of the compressor covers procedures for mesh generation and CFD code calculations. This model has been verified by experimental data.

It has been studied how compressor blades with nicks and bending affect the compressor performance and how compressor map changes. The studies resulted in the following conclusions:

-The existing limits on damages size do not cause serious problems in operation. It was confirmed by the calculation result.

- As the result of this compressor study, the critical size of blade nicks (more than 4mm or more than 6% blade chord) and bending (more than 0,023b in the leading edge in the circumferential direction) has been identified in terms of aerodynamics.
A Conjugate Heat Transfer and Thermal Stress Analysis of Film-Cooled Superalloy With Thermal Barrier Coating
Authors: Chen Xiaohu , Li Jiao , Long Yun , Wang Yuzhang , Weng Shilie , Yavuzkurt Savas
Published: January 2021

A conjugate heat transfer study is carried out to obtain temperature and thermal stress field of a film-cooled superalloy with multi-layer thermal barrier coatings (TBCs). The aim is to understand the effects of the blowing ratio and ceramic top coating (TC) thickness on temperature and thermal stress which have an influence on component reliability and life. Results reveal that the distribution of film cooling effectiveness gets more uniform as TC thickness decrease because thick TC with low thermal conductivity prevents heat conduction in the axial and spanwise directions. In the upstream of the film cooling hole, the cooling effect is enhanced nonlinearly with the increase of the blowing ratio since the flow separation in the cooling tube affects the heat transfer enhancement. The insulation performance is improved by about 10 K for every 0.1D increase in TC thickness and the cooling effect is improved by about 20 K when the blowing ratio is increased from 0.5 to 1.0 at the leading edge of the film-cooling tube. The influence of jet lift-off and hotgas entrainment on the insulation effect is greater than TC thickness. The stress is concentrated at the leading edge of the film cooling hole and interfaces of TBCs. The maximum Von-Mises stress (761 MPa) on the interfaces is not at the leading or trailing sides of the film-cooling tube, it is about ± 45° from the centerline of the BC/SUB interface. The debonding stress at TC/BC interface and BC/SUB interface are about 26 MPa and 175 MPa respectively. The normal stress near the film-cooling tube on the BC/SUB interface is 5 – 7 times the one at TC/BC interface. Therefore, the interface crack is more likely to initiate at the BC/SUB interface, and the crack may keep growing and cause the spalling of TBC.
Estimation of Aircraft Engine Flight Mission Severity Caused by Erosion
Authors: Brandes Tim , Koch Christian , Staudacher Stephan
Published: January 2021

More and more attention is being devoted to assessing severity of the engine operation for a high number of flights in a minimum of time. Compressor erosion is one of the physical phenomena contributing to this severity. Hence, an effective method is developed which allows a general judgment of the severity of engine operation with regards to compressor erosion. The shortening of the camber line at blade leading edge is selected as the parameter describing the degree of severity. The particle impingement conditions experienced by compressor blades throughout a flight mission are computed using a flight mission simulation and a non-dimensional engine model. Local flow conditions of all compressor blade rows are derived from mean line computations. A dimensional analysis of a straight through swirling annulus flow led to a simplified model of particle separation within the compressor blade rows. It turns out, that bypass ratio, bleed setting and degree of particle separation changing from operating point to operating point are significant drivers of erosion. Fan root and booster suffer less from compressor erosion than the high pressure compressor. The flight segments taxi, take-off, take-off climb, climb and cruise are significantly impacting the severity of a flight mission with regards to compressor erosion.
Squeeze Film Damper Bearing With Double-Ended Beam Centering Springs: Part I — Design and Analysis
Authors: Li Wei , Braman Christopher , Hantz Brian , Thorat Manish , Pettinato Brian
Published: January 2021

Squeeze film damper (SFD) bearings are widely used in industry to enhance rotor dynamic stability in super-critical applications. This study examines an SFD bearing design with double-ended beam centering springs placed external to the squeeze film and in parallel with O-ring seals. The purpose of the new SFD bearing design is to minimize the use of O-rings as a support and centering device, instead relying on compact external springs that can be independently adjusted to ensure centered operation. The new design is applicable to a wide range of bearing sizes and rotor weights with variable spring stiffness, damping value and envelope dimensions.

Spring stiffness and stress coefficients were generated for 3.5-inch bearing and SFD assembly from a parametric finite element analysis (FEA). High cycle fatigue of the springs was evaluated using the Soderberg criterion with an additional safety factor. Rotor-dynamic performance of the new design was analyzed using an historical rotor applying both π-film and full-film models. To evaluate the design, the same 3.5 inch SFD bearing presented in this study was manufactured and tested in succeeding work.
The Story of the Dent-Gouge Fracture Model
Authors: Cosham Andrew , Hopkins Phil
Published: January 2021

Once upon a time the dent-gouge fracture model was developed by the then British Gas Corporation to estimate the burst pressure of a dent and gouge subject to internal pressure. The dent-gouge fracture model is based on a two-dimensional representation of a dent and gouge; it assumes an infinitely long, longitudinally-orientated gouge (a crack) at the base of infinitely long, longitudinally-orientated dent. The model was calibrated using the results of 109 ring tests and 23 vessel tests conducted by the British Gas Corporation; a dent was introduced and then a slot was machined in the base of the dent (all at zero pressure). It is a semi-empirical model. Part 12 of API 579-1/ASME FFS-1 2016 quotes the original dent-gouge fracture model.

A number of variations on the theme of the original dent-gouge fracture model have been developed. The variants have not significantly improved the accuracy of the original model, as is demonstrated by comparing the variants against the results of burst tests on rings and vessels containing a dent and gouge (or notch) reported in the published literature.

The dent-gouge fracture model is deconstructed in order to illustrate its component parts. The deconstruction clearly identifies the parts of the model that could be improved. It also highlights where semi-empiricism is embedded in the model. The effect of changes to the original model is illustrated using the results of the full-scale tests. The difficulties introduced by the scatter in the full-scale tests are discussed, noting that a number of different methods have been used to introduce the dent and gouge (or notch) into the ring or vessel. A factor of safety is proposed.

Pointers are given to how the dent-gouge fracture model might be improved or replaced. The need for a dent-gouge model is also considered, in the context of the guidance given in API Recommended Practice 1160 and ASME B31.8S.
Application of Noise Filtering Techniques for the Quantification of Uncertainty in Dent Strain Calculations
Authors: Ergezinger Noah , Virk Amandeep Singh , Woo Janine , Kainat Muntaseer , Adeeb Samer
Published: January 2021

The integrity assessment of dents in pipelines is primarily driven by the dent depths as per the stipulations in current codes and standards. There is a provision for strain-based analysis to quantify the severity of dents based on their shapes in the ASME B31.8 non-mandatory Appendix R. In recent years, the pipeline industry has also started leveraging more advanced techniques such as Finite Element Analysis (FEA) for dent assessment. These assessments require the detailed deformation profile of dents, which are available from In-line Inspection (ILI) tools.

The ILI tools use caliper arms that roll along the inside of the pipeline and scan the inner profile. The measurements recorded by each caliper arm are susceptible to noise due to the vibration of the ILI tool, and as a result, the dent shapes obtained from ILI are not smooth. Strain assessments of dents typically require the calculation of radius of curvature in the longitudinal and circumferential directions. This becomes a complex problem while the ILI data contains noise, particularly for relatively shallow dents, when the dent depth approaches the magnitude of the noise in the data. In these cases, the radius of curvature estimation can become highly inaccurate. Furthermore, the amount of noise in the data can vary between dents, and so the accuracy of the estimation varies as well.

This paper presents several methods to resolve the above-mentioned issues. To address the issue of data noise itself, a combination of Fast Fourier Transform (FFT) and Gaussian filtering is used to produce a smooth profile that can be used to calculate the maximum radius of curvature of the dent. The smoothed profile also results in a better estimation of dent depth. To estimate the amount of uncertainty in the data, we apply many independent iterations of random noise to the smoothed curve. Characteristics required for further reliability analysis, such as dent depth or radius of curvature, are calculated for each iteration. This forms a distribution for each characteristic, and the properties of each distribution are used to quantify the uncertainty in the ILI data.
Leveraging IOT Telemetry to Improve the Tracking of Inline Inspection Tools for Oil and Gas Pipelines
Authors: Shankar Vignesh , Li Herb , Pozniak Eric , Onuoha Chukwuma , McDonnell Shamus
Published: January 2021

To ensure the safe transportation of energy, Canadian pipeline operators spend roughly $1.5 billion every year on pipeline integrity. The most practiced form of pipeline integrity is the use of inline inspection (ILI) tools. To ensure that an ILI inspection occurs with minimal to no complications, operators often utilize tracking techniques for the runs. These techniques can be costly and have large safety risks and environmental impacts due to the nature of using manpower to perform the operation.

Using advanced Intemet of Things (IOT) telemetry devices, the tracking of ILI tools can be completed from remote locations by installing IOT devices semi-permanently along a pipeline right -of-way. This advancement has ensured the efficient, safe and reliable tracking of ILI tools while eliminating risks involved with conventional tracking. Furthermore, the current generation of IOT telemetry devices offers a tailored suite of ILI tracking sensors such as magnetics, ultrasonic frequency, extremely low frequency (22 Hz), and geophone. This multi sensor tracking solution increases an operator’s confidence in pig passages and flow rate estimations which allows the operator to optimize pump station bypassing. Finally, the IOT telemetry devices are supported by Global System for Mobile Communications (GSM) and satellite link which has ensured global coverage to remotely track tools. The communication module for the semi-permanent tracking solution is decided based on network availability and endpoints.

This paper will present a comprehensive analysis that compares conventional ILI tracking to cutting-edge IOT telemetry ILI tracking and illustrates improvements in operational efficiency, operational risk, overall safety, environmental impact, and cost-effectiveness. In addition, case studies from recent tracking runs will be shared to demonstrate advancements in IOT telemetry, tracking sensor technology, dynamic user interface capabilities, advanced data dissemination methods, and high precision benchmarking.
Performance Evaluation of White Coconut Oil Based Metal Working Fluid (MWF) Under Minimum Quantity Lubrication (MQL) for Machining of Inconel 718 and AISI 304
Authors: Wickramasinghe K. C. , Sasahara Hiroyuki , Masatoshi Usui
Published: January 2021

Machining is one of the most prominent manufacturing methods in automobile, aerospace and marine industries. The materials which are frequently consumed in such industries are hard to machine through conventional techniques. Therefore, it requires sophisticated process approaches and better cooling and lubrication environment. Hence, industries trend to use petroleum oil based MWFs because of the better cooling and lubrication properties. However, petroleum oil based MWFs express adverse health and environment effect throughout their lifecycle. Authors have formulated a white coconut oil based MWF as an alternative to the hazardous petroleum oil based MWF. The performance of the novel white coconut oil based MWF was evaluated via MQL approach for Inconel 718 and AISI 304. Machining experiments were conducted to investigate work tool interface temperature, cutting forces and compared them with commercially available MWF. Favorable results for the work tool interface temperature and cutting forces were obtained for the newly formulated MWF compared to the industrial available petroleum oil based MWF. Hence, the industrial applicability of the formulated MWF was confirmed for the selected cutting specifications for both work materials.
Smooth Path Blending for 5-Axis Machine Tools
Authors: Tajima Shingo , Sencer Burak , Yoshioka Hayato , Shinno Hidenori
Published: January 2021

5-axis machining is widely used to manufacture complex sculptured parts, such as impellers used in jet engines. In order to machine complex part surfaces, the surface is discretized by a series of short-segmented point to point linear segments by CAD/CAM systems. Smooth non-stop motion of the tool must be interpolated along those discrete tool-paths. This paper proposes novel discrete linear path smoothing algorithms to interpolate tool position and orientation commands synchronously for 5-axis machining. Finite Impulse Response (FIR) filtering based feed profiling technique is developed to generate a smooth tool-pose trajectory with both local and global smoothing functionality. Analytical techniques are proposed to confine the blending errors within user specified tolerances. The proposed technique is computationally efficient and suitable for real-time implementation on modern NC systems. Path blending errors are defined in both the Cartesian workpiece coordinate system for tool positioning errors and the spherical coordinate system for tool orientation errors. Both position and orientation contouring errors are controlled in each coordinate system with respect to the user-defined tolerances. Simulation results validate that the proposed FIR based corner smoothing algorithm can generate smooth and non-stop trajectories for 5-axis machining. It can lead to significant cycle time gain without jeopardizing part tolerances.
Low Friction Realised by Hydrogen-Ended DLC Surface Through Photocatalyst Effect in Water Lubricated Condition
Authors: Murashima Motoyuki , Imaizumi Yusuke , Yamada Takazumi , Shotaro Katsuno , Yoshida Tomoki , Umehara Noritsugu , Tokoroyama Takayuki
Published: January 2021

This study shows a new friction reduction method for a diamond-like carbon (DLC) coating using photocatalyst in water lubricated condition. It is well known that one of DLC coatings (e.g. hydrogenated amorphous carbon, a-C:H) exhibits low friction due to repulsive force generated by hydrogens on their top most surfaces. Thus, the low friction is mainly occurred in inert gas environment. On the other hand, if we can produce hydrogenated surface positively, low friction may be achieved in lubricated conditions. Here, it is well known that water electrolysis by photocatalyst generates hydrogen and oxygen atoms/molecules. In this research, we propose a new hydrogen terminating method for DLC surfaces with hydrogens generated by water electrolysis. Moreover, we clarified the effect of the hydrogen-end on lowering friction. We conducted friction tests using an a-C:H coating against a TiO2 disk (photocatalyst) in water lubricated condition. The friction test result showed a decrease in the friction coefficient which was associated with UV irradiation. It is considered that the reduction in hydrogen-bonding component of surface energy indicates a highly hydrogen-ended surface creation, resulting in higher repulsive force and lower friction.
Molecular Dynamic Simulation of Micro-Structured Diamond Tool in Silicon Carbide Cutting
Authors: Liu Changlin , Chu Jianning , Ke Jinyang , Chen Xiao , Zhang Jianguo , Xiao Junfeng , Xu Jianfeng
Published: January 2021

Silicon carbide (SiC) is a material of great interest in many industrial applications. However, due to the hardness and brittleness nature, achieving ultra-precision machining of SiC is still challenging. In recent years, function surface with micro-structures has been introduced in cutting tool to suppress wear process. But the wear mechanism of the structured tool has not been revealed completely. Therefore, in present research, molecular dynamic simulations were conducted to investigate the influence of the micro-structure on the nano scale cutting process of 3C-SiC. The simulation results showed that the dislocation propagation in workpiece can be suppressed with a structured tool. The micro-structures have a great influence on the stress distribution in the workpiece subsurface. Furthermore, the abrasive wear of the structured tool is obvious smaller since the edges of the tool became blunt and the contact face between tool and workpiece changed to the close-packed plane of diamond. Moreover, the amorphization of the structured tool is effectively suppressed. This study contributes to the understanding of the details involved in the ultra-precision cutting of SiC.
Sequence-Dependent Robotic Disassembly Line Balancing Problem Considering Disassembly Path
Authors: Chen Qinglian , Yao Bitao , Pham Duc Truong
Published: January 2021

For the realization of environmental protection and resource conservation, remanufacturing is of great significance. Disassembly is a key step in remanufacturing, the disassembly line system is the main scenario for product disassembly, usually consisting of multiple workstations, and has prolific productivity. The application of the robots in the disassembly line will eliminate various problems caused by manual disassembly. Moreover, the disassembly line balancing problem (DLBP) is of great importance for environmental remanufacturing. In the past, disassembly work was usually done manually with high cost and relatively low efficiency. Therefore, more and more researches are focusing on the automatic DLBP due to its high efficiency. This research solves the sequence-dependent robotic disassembly line balancing problem (SDRDLBP) with multiple objectives. It considers the sequence-dependent time increments and requires the generated feasible disassembly sequence to be assigned to ordered disassembly workstations according to the specific robotic workstation assignment method. In robotic DLBP, due to the special characteristics of robotic disassembly, we need to consider the moving time of the robots’ disassembly path during the disassembly process. This is also the first time to consider sequence-dependent time increments while considering the disassembly path of the robots. Then with the help of crossover and mutation operators, multi-objective evolutionary algorithms (MOEAs) are proposed to solve SDRDLBP. Based on the gear pump model, the performance of the used algorithm under different cycle times is analyzed and compared with another two algorithms. The average values of the HV and IGD indicators have been calculated, respectively. The results show the NSGA-II algorithm presents outstanding performance among the three MOEAs, and hence demonstrate the superiority of the NSGA-II algorithm.
Design Framework for Preparing Workforce Towards Industry 4.0 Implementation in Small and Medium-Sized Enterprises
Authors: James Sagil , Shetty Anupam
Published: January 2021

The fourth industrial revolution, also known as Industry 4.0 is a new paradigm that is significantly influencing several manufacturing industries across the globe. Industry 4.0 synchronizes concepts such as Smart Manufacturing, Smart Factory, and the Internet of Things with existing factory automation technologies in order to improve value in manufacturing by monitoring key performance indicators and creates value in all manufacturing related aspects. Currently, several large companies industries have started early initiatives for implementing these technologies. However, small and medium-sized enterprises (SMEs) face massive challenges in adopting Industry 4.0 technologies. As the SMEs are evaluating their readiness for implementing the Industry 4.0 concepts, several challenges need to be addressed, including high initial investment, lack of standardization, data security, and lack of skilled labor. A strategic roadmap towards implementing the Industry 4.0 paradigms is still unclear in the SME sector as well as in academia. This research focuses on designing a framework for training/retraining the strong workforce for SMEs to enable Industry 4.0 adoption and implementation. The framework is created using qualitative research methods followed by the secondary data collection approach. The study suggests the use of a three-step implementation process consisting of 1) creating new jobs, 2) recruiting, and 3) retraining and retaining the talent. The results of this study are expected to create a platform to train the workforce for Industry 4.0, reduce skill gaps, and retain incumbent workers in the manufacturing sector.
IoT Devices and Applications for Wire-Based Hybrid Manufacturing Machine Tools
Authors: Thien Austen , Saldana Christopher J. , Feldhausen Thomas , Kurfess Thomas
Published: January 2021

Hybrid manufacturing machine tools have the potential to be a disruptive technology as they can leverage the benefits of both additive and subtractive manufacturing by incorporating both processes on the same machine while limiting the downsides of the individual processes. Since these machines use two very disparate manufacturing processes and hybrid manufacturing is an emerging technology, it will be useful to monitor data coming from the machine and apply it to improve the manufacturing process, the operation of the machine, and to integrate the machine into the larger digital framework of Industrial Internet of Things (IoT). The present work discusses IoT devices that would be beneficial to add to a hybrid machine tool as well as applications for those devices. The proposed methods discussed in this work have not been experimentally implemented on a hybrid machine tool and so there are no performance data available yet. The hybrid machine tool used as a basis to generate these IoT applications is the Mazak VC-500A/5x AM Hot Wire Deposition, which is a 5-axis machine tool incorporated with a wire feedstock 4kW laser deposition system. Methodologies and applications will be outlined for machine health and process monitoring. Other areas covered include process benchmarking, secure networking options for the proposed IoT framework, and hybrid process improvement. Limitations of these methods and future work for new sensor devices and application areas is also discussed.
Initial Process Planning of a Hybrid Multi-Tasking Platform
Authors: DeWitte Lisa N. , Saldana Christopher J. , Feldhausen Thomas A. , Kurfess Thomas R.
Published: January 2021

Applications of hybrid technology are expanding from refurbishment and repair to low quantity, specialty part production, which are staple characteristics in medical implant, energy, and aerospace industry sectors, among others. This expansion has led to the development of the Mazak VC-500A/5X AM HWD, a wire fed laser cladding unit equipped with a standard 5 axis CNC. This unit is capable of building near net geometry of complex medium to large parts within a profitable timeframe, due to its comparatively high rate of deposition to that of a powder fed hybrid system. In this study, deposition and machining capabilities of the VC-500A/5X AM HWD are assessed through the production of three different test geometries by different process plans. Production of these test geometries is supported by an open loop sensor package primarily for monitoring machine health, data collection, and machine operator aid. The viability of extended deposition followed by machining is evaluated against a more cyclical strategy of reoccurring deposition and machining operations. Lastly, common defects in as-built geometries are evaluated and addressed through revisions to original process plans and toolpaths, indicating the need for continued innovation in hybrid manufacturing specific CAM/CAD software, as well as closed loop machine monitoring and quality control.
Laser Engineered Net Shaping In-Situ Synthesis of NiTi Alloy: Effects of Processing Parameters
Authors: Zhang Dongzhe , Li Yunze , Wang Hui , Cong Weilong
Published: January 2021

Nickel-Titanium (NiTi) alloy is difficult to be machined and fabricated due to its properties of rapid work-hardening and superelasticity. Traditional manufacturing methods, such as casting, vacuum arc melting, and hot-isostatic pressing, have disadvantages of high cost, time-consuming, and limitation in the complexity of parts’ fabrication. In order to reduce or solve these problems, laser additive manufacturing methods have been studied in the fabrication of NiTi alloy. Among the investigations, laser engineered net-shaping (LENS) in-situ synthesis of NiTi from blended Ni and Ti powders shows its unique advantage of cost-effectiveness and flexibility in tailoring NiTi’s phase transformation properties. In addition, it is reported that LENS in-situ synthesized NiTi parts have comparable properties with NiTi alloys fabricated from pre-alloyed powders. However, there are no existing investigations on the effects of processing parameters on the mechanical properties of the LENS in-situ fabricated NiTi parts. The processing parameters would have great influences on the properties of the LENS in-situ synthesized NiTi parts. This paper, for the first time, reports the effects of laser power, powder feeding rate, and Z increment of the deposition head on microstructure, microhardness, and Young’s modulus of the LENS in-situ synthesized NiTi parts.
The Effect of Assembly Instructions and Part Organization on Assembly Time and Process Variation
Authors: Wescoat Ethan , Krugh Matthew , Krishnan Gayathry , Mears Laine
Published: January 2021

In mass production, planning for customized products is difficult to achieve against the effort toward standardization of parts and processes. In a complex product such as a vehicle, varying an entire subassembly multiple times per shift increases the margin of error for defects and slows the production rate. To understand the effect of assembly instructions and part organization on assembly time as a result of process variation, this study examines building different subassemblies of two different models to simulate a customized production line. Assembly time is measured while varying the work instructions, part organization, and subassembly type, and relationships among these variables drawn. Picture instructions result in shorter assembly times for all subassemblies, while line configurations for shape and color part organization have the shortest assembly times. However, only picture instructions for two out of four subassemblies show a statistically significant effect on lowering assembly time characterized by a p-value below 0.1. Based on a linear model, total product assembly time is predicted within a 20% margin of error, based on which subassemblies are built and instructions used. Based on these preliminary tests, a better experimental plan is needed to isolate test variables for model creation. In addition, more experimental data is required to improve the statistical significance of the results. A heavier emphasis should be placed on the cognitive factors of the assembler in assembly production planning.
New species of Gamasellodes Athias-Henriot and Zerconopsis Hull (Mesostigmata: Ascidae) from Colombia, with a complement to a recently published key to the world species of Gamasellodes, and with a key to the world species of Zerconopsis

Authors: Mesa Cobo Nora Cristina , Abo-shnaf Reham I.a. , Rueda-ramirez Diana Marcela , De Castro Luiz A.s. , De Moraes Gilberto J.
Published: January 2021

Gamasellodes unalpalmi Mesa, Abo-Shnaf & Rueda-Ramirez sp. nov. and Zerconopsis zumbambicae Mesa, Abo-Shnaf & Rueda-Ramirez sp. nov. are described based on the morphology of adults obtained from litter and soil samples collected at Valle del Cauca province, Colombia. A complement to a recently published key to the world species of Gamasellodes and a key for the separation of females of the 18 recognizable world species of Zerconopsis are provided.
Review of free-living predatory cheyletid mites (Acari: Cheyletidae) of Western Siberia, Russia

Authors: Khaustov Alexander A.
Published: January 2021

Investigation of diversity of free-living predatory mites of the family Cheyletidae in Western Siberia, Russia, undertaken for the first time, has recorded 10 species, of which eight species are new for this region. Description of a new species Eutogenes bicornis sp. nov. includes all active stages; a male of Cheletomimus (Hemicheyletia) recki (Volgin, 1966) comb. nov. is redescribed and its remanining active stages are described for the first time; Cheyletus rashtiensis Salarzehi et al. 2018 is recorded from Russia for the first time, and its female is redescribed, and tritonymph is described for the first time; Chelacheles apanaskevichi Bochkov and Abramov, 2016, Cheletacarus raptor Volgin, 1961, Paracheyletia pyriformis (Banks, 1904), Cunliffella whartoni (Baker, 1949), and Bothrocheyla pavlovskyi (Volgin, 1964) are recorded from Western Siberia for the first time. Nomenclature of some setal structures of legs is discussed.
Spider mites (Acari: Tetranychidae) from Serbia: new species for the country and the Balkan Peninsula, with a key to all known Serbian species
Authors: Marić Ivana , Međo Irena , Marčić Dejan , Petanović Radmila , Jovanović Slobodan , Ueckermann Edward A.
Published: January 2021

Seven spider mite species were recorded for the first time in Serbia: Bryobia macedonica Hatzinikolis & Panou, 1996 and Bryobia querci Hatzinikolis & Panou, 1997 from Bryobiinae, and Eutetranychus orientalis Klein, 1936; Oligonychus bicolor Banks, 1894; Oligonychus platani McGregor, 1950 Tetranychus canadensis McGregor, 1950 and Tetranychus ludeni Zacher, 1913 from Tetranychinae. Together with previously reported data, these findings raise the number of known tetranychid species in Serbia to 44, the second highest number of spider mite species recorded in the Balkan countries. The records of O. bicolor and T. canadensis are also the first ones on the Balkan Peninsula. The most frequent species were T. ludeni and E. orientalis, found in 24 and 13 out of 57 sampling locations. Spider mites were recorded on host plants in four basic habitat types, but predominantly in cultivated habitats and woodlands. A total of 27 plant species from nine families were recorded as hosts for newly recorded spider mites, including 12 plant species as new hosts for four tetranychids, and three plant species as new hosts for the family Tetranychidae. Plant family Rosaceae had the highest number of new hosts (7) and harbored the highest number of spider mite species (5). Tetranychus ludeni had the highest number of host plants (11) with two plant species as its new hosts. Oligonychus bicolor was found on eight host plants including five new hosts for this species and one new host for the family Tetranychidae. The other two new hosts for the family Tetranychidae harbored O. platani and B. querci, respectively. Symptoms of heavy infestations by E. orientalis and T. ludeni were recorded on host plants in several locations.
Holographic extraction of plane waves from an ultrasound beam for acoustic characterization of an absorbing layer of finite dimensions
Authors: Nikolaev Dmitry A. , Tsysar Sergey A. , Khokhlova Vera A. , Kreider Wayne , Sapozhnikov Oleg A.
Published: January 2021

For the acoustic characterization of materials, a method is proposed for interpreting experiments with finite-sized transducers and test samples in terms of the idealized situation in which plane waves are transmitted through an infinite plane-parallel layer. The method uses acoustic holography, which experimentally provides complete knowledge of the wave field by recording pressure waveforms at points on a surface intersected by the acoustic beam. The measured hologram makes it possible to calculate the angular spectrum of the beam to decompose the field into a superposition of plane waves propagating in different directions. Because these waves cancel one another outside the beam, the idealized geometry of an infinite layer can be represented by a sample of finite size if its lateral dimensions exceed the width of the acoustic beam. The proposed method relies on holograms that represent the acoustic beam with and without the test sample in the transmission path. The method is described theoretically, and its capabilities are demonstrated experimentally for silicone rubber samples by measuring their frequency-dependent phase velocities and absorption coefficients in the megahertz frequency range.
Feasibility of remote assessment of the binaural intelligibility level difference in school-age children
Authors: Merchant Gabrielle R. , Dorey Claire , Porter Heather L. , Buss Emily , Leibold Lori J.
Published: January 2021

This work evaluated the feasibility and reliability of remotely assessing masked speech recognition and the binaural intelligibility level difference (BILD) in children. Participants were 28 children (6–17 years) and 11 adults (22–45 years) with self-reported normal hearing. A three-alternative forced-choice word recognition task was completed using participants' personal hardware (headphones and computer) and custom software that uploaded results to a central database. Results demonstrate that assessment of masked speech recognition and the BILD is feasible and generally reliable in a remote setting. Variability of results across individuals would likely have been reduced by distributing or specifying appropriate headphones.
The Rab32/BLOC-3–dependent pathway mediates host defense against different pathogens in human macrophages
Authors: Baldassarre Massimiliano , Solano-Collado Virtu , Balci Arda , Colamarino Rosa A. , Dambuza Ivy M. , Reid Delyth M. , Wilson Heather M. , Brown Gordon D. , Mukhopadhyay Subhankar , Dougan Gordon , Spanò Stefania
Published: January 2021

The small GTPase Rab32 and its exchange factor BLOC-3 complex control a new antimicrobial activity in mouse and human macrophages.
Overlap of NatA and IAP substrates implicates N-terminal acetylation in protein stabilization
Authors: Mueller Franziska , Friese Alexandra , Pathe Claudio , da Silva Richard Cardoso , Rodriguez Kenny Bravo , Musacchio Andrea , Bange Tanja
Published: January 2021

N-terminal acetylation by NATA acetyltransferase shields many of its targets from inhibitor of apoptosis ubiquitin ligases.
Structure and noncanonical Cdk8 activation mechanism within an Argonaute-containing Mediator kinase module
Authors: Li Yi-Chuan , Chao Ti-Chun , Kim Hee Jong , Cholko Timothy , Chen Shin-Fu , Li Guojie , Snyder Laura , Nakanishi Kotaro , Chang Chia-en , Murakami Kenji , Garcia Benjamin A. , Boyer Thomas G. , Tsai Kuang-Lei
Published: January 2021

The structure of Mediator kinase module reveals its Med12-dependent Cdk8 activation mechanism and an Argonaute-like Med13 protein.
Direct coherent multi-ink printing of fabric supercapacitors
Authors: Zhao Jingxin , Lu Hongyu , Zhang Yan , Yu Shixiong , Malyi Oleksandr I. , Zhao Xiaoxin , Wang Litong , Wang Huibo , Peng Jianhong , Li Xifei , Zhang Yanyan , Chen Shi , Pan Hui , Xing Guichuan , Lu Conghua , Tang Yuxin , Chen Xiaodong
Published: January 2021

A direct coherent multi-ink writing 3D printing technology constructs coaxial fiber-shaped asymmetric supercapacitors.
Systemic inequalities for LGBTQ professionals in STEM
Authors: Cech E. A. , Waidzunas T. J.
Published: January 2021

LGBTQ STEM professionals experience more career limitations, devaluation, health issues, and attrition intentions than their peers.
Changes in Bacterial and Chemical Components and Growth Prediction for Lactobacillus sakei during Kimoto-Style Fermentation Starter Preparation in Sake Brewing: a Comprehensive Analysis
Authors: Takahashi Masayuki , Morikawa Kana , Kita Yasuko , Shimoda Takamasa , Akao Takeshi , Goto-Yamamoto Nami
Published: January 2021

It is important to produce lactic acid in kimoto-style seed mash; however, the bacterial transition is different depending on the sake brewery. The reason why there are diverse bacterial transitions during kimoto-style seed mash preparation for each sake brewery is unclear so far, and it causes difficulty in starting kimoto-style seed mash.
Seeing and Touching the Mycomembrane at the Nanoscale
Authors: Viljoen Albertus , Räth Esther , Mckinney John D. , Fantner Georg E. , Dufrêne Yves F.
Published: January 2021

Mycobacteria have unique cell envelopes, surface properties, and growth dynamics, which all play a part in the ability of these important pathogens to infect, evade host immunity, disseminate, and resist antibiotic challenges. Recent atomic force microscopy (AFM) studies have brought new insights into the nanometer-scale ultrastructural and mechanical properties of mycobacteria.
Alkaline pH Increases Swimming Speed and Facilitates Mucus Penetration for Vibrio cholerae
Authors: Nhu Nguyen T. Q. , Lee John S. , Wang Helen J. , Dufour Yann S.
Published: January 2021

The diarrheal disease cholera is still a burden for populations in developing countries with poor sanitation. To develop effective vaccines and prevention strategies against
Vibrio cholerae
, we must understand the initial steps of infection leading to the colonization of the small intestine.
Staphylococcus aureus Trigger Factor Is Involved in Biofilm Formation and Cooperates with the Chaperone PpiB
Authors: Keogh Rebecca A. , Zapf Rachel L. , Frey Andrew , Marino Emily C. , Null Gillian G. , Wiemels Richard E. , Holzschu Donald L. , Shaw Lindsey N. , Carroll Ronan K.
Published: January 2021

S. aureus
encodes a large number of virulence factors that aid the bacterium in survival and pathogenesis. These virulence factors have a wide variety of functions; however, they must all be properly secreted in order to be functional.
Outcomes of a uniformly active approach to infants born at 22–24 weeks of gestation
Authors: Söderström Fanny , Normann Erik , Jonsson Maria , Ågren Johan
Published: January 2021

Objective

To determine survival and outcomes in infants born at 22–24 weeks of gestation in a centre with a uniformly active approach to management of extremely preterm infants.

Study design

Single-centre retrospective cohort study including infants born 2006–2015. Short-term morbidities assessed included retinopathy of prematurity, necrotising enterocolitis, patent ductus arteriosus, intraventricular haemorrhage, periventricular malacia and bronchopulmonary dysplasia. Neurodevelopmental outcomes assessed included cerebral palsy, visual impairment, hearing impairment and developmental delay.

Results

Total survival was 64% (143/222), ranging from 52% at 22 weeks to 70% at 24 weeks. Of 133 (93%) children available for follow-up at 2.5 years corrected age, 34% had neurodevelopmental impairment with 11% classified as moderately to severely impaired. Treatment-requiring retinopathy of prematurity, severe bronchopulmonary dysplasia, visual impairment and developmental delay correlated with lower gestational age.

Conclusions

A uniformly active approach to all extremely preterm infants results in survival rates that are not distinctly different across the gestational ages of 22–24 weeks and more than 50% survival even in infants at 22 weeks. The majority were unimpaired at 2.5 years, suggesting that such an approach does not result in higher rates of long-term adverse neurological outcome.