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Solving Recent Challenges for Wrought Ni-Base Superalloys

METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE 2020年第6期51卷 2626-2650页

作者： Hardy, M. C. Detrois, M. McDevitt, E. T. Argyrakis, C. Saraf, v. Jablonski, P. D. Hawk, J. A. Buckingham, R. C. Kitaguchi, H. S. Tin, S. Rolls Royce Plc POB 31 Derby DE24 8BJ England US DOE Natl Energy Technol Lab 1450 Queen Ave SW Albany OR 97321 USA LRST 1450 Queen Ave SW Albany OR 97321 USA Allegheny Technol Inc Specialty Mat 2020 Ashcraft AvePOB 5030 Monroe NC 28111 USA Allegheny Technol Inc Forged Prod Cudahy POB 89025481 S Packard Ave Cudahy WI 53110 USA Univ Birmingham Sch Met & Mat Birmingham B15 2TT W Midlands England IIT Dept Mech Mat & Aerosp Engn 10 West 32nd St Chicago IL 60616 USA

This paper reviews the status of technology in design and manufacture of new wrought polycrystalline Ni-base superalloys for critical engineering applications. There is a strong motivation to develop new alloys that are capable of operating at higher temperatures to realize improvements in thermal efficiency, which are necessary to achieve environmental targets for reduced emissions of harmful green-house gases. From the aerospace sector, the development of new powder metallurgy and ingot metallurgy alloys is discussed for disk rotor and static applications. New compositions for powder metallurgy contain about 50 to 55 pct of gamma prime (gamma ') strengthening precipitates to ensure components operate successfully at temperatures up to 788 degrees C (1450 degrees F). In contrast, new compositions for ingot metallurgy aim to occupy a design space in temperature capability between Alloy 718 and current powder alloys that are in-service, and show levels of gamma ' of about 30 to 44 pct. The focus in developing these alloys was design for manufacturability. To complement the aerospace developments, a review of work to understand the suitability of candidate alloys for multiple applications in Advanced-Ultra Supercritical (AUSC) power plants has been undertaken by Detrois, Jablonski, and Hawk from the National Energy Technology Laboratory. In these power plants, steam temperatures are required to reach 700 degrees C to 760 degrees C. The common thread is to develop alloys that demonstrate a combination of high-temperature properties, which are reliant on both the alloy composition and microstructure and can be produced readily at the right price. For the AUSC applications, the emphasis is on high-temperature strength, long-term creep life, phase stability, oxidation resistance, and robust welding for fabrications. Whereas for powder disk rotors in aircraft engines, the priority is enhanced resistance to time-dependent crack growth, phase stability, and resistance to env

关键词： Powder metallurgy

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基于SiGe BiCMOS W波段混频器设计

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微波学报 2023年第S01期39卷 382-385页

作者：陈翔周春霞程国枭吴文南京理工大学、电子工程与光电技术学院、近程射频感知芯片与微系统教育部重点实验室南京210094

基于130nm SiGe BiCMOS工艺,本文采用双吉尔伯特单元结构设计了一款高线性度的下变频混频器。在混频器的跨导级加入退化电感提高混频器的线性度,并且在中频输出端使用有源双转单电路,实现单端输出并提供增益。版图仿真结果表明,在本振... 详细信息

基于130nm SiGe BiCMOS工艺,本文采用双吉尔伯特单元结构设计了一款高线性度的下变频混频器。在混频器的跨导级加入退化电感提高混频器的线性度,并且在中频输出端使用有源双转单电路,实现单端输出并提供增益。版图仿真结果表明,在本振功率为4dBm时,转换增益为4.89dB,噪声系数为15.44dB,在本振信号为90G,射频信号为91G时,输入1dB压缩点P1dB为-0.02dBm,在3.3v的工作电压下,工作电流为14.1mA,功耗为46.53mW。

关键词： W波段下变频混频器高线性度

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Lighting design of an indoor sports field 20

Lighting design of an indoor sports field

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current developments in Lens design and optical engineering XX 2019

作者： Lee, Xuan-Hao Lin, Shih-Kang Yu, Yeh-Wei Yang, Tsung-Hsun Sun, Ching-Cherng Department of Optics and Photonics National Central University Taoyuan City32001 Taiwan Department of Optics and Photonics Feng Chia University Taichung City40724 Taiwan

ISBN: (数字)9781510629028

ISBN: (纸本)9781510629011

In this paper, an efficient lighting design for indoor sport field is presented. The average illuminance for the indoor sport field with eight playing courts can be achieve to 500 lx at a 11.2 m of the lamp's mounting height. Besides, because of specific arrangement of luminaires, the proposed lighting design can effectively reduced the glare effect and provide a comfortable illumination to players. © 2019 SPIE.

关键词： Light emitting diodes

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Flexible Zno:Pvdf Based Free Standing Piezoelectric Nanogenerator for vibrational Energy Harvesting and Wearable Shoe Insole Pedometer Sensor

SSRN

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SSRN 2023年

作者： Mahapatra, Abhinav Ajimsha, R.S. Ittoop, M.O. Sharma, Arpit Karmakar, Sanjib Shaikh, Aasiya Sankar, P. Ram Misra, Pankaj Oxide Nano-Electronics Lab Laser Material Processing Division Raja Ramanna Centre for Advanced Technology Indore452013 India Homi Bhabha National Institute Training School Complex Anushakti Nagar Mumbai400 094 India Materials Engineering Lab Laser Material Processing Division Raja Ramanna Centre for Advanced Technology Indore452013 India Shri G. S. Institute of Technology and Science Indore452 003 India Optical and Dielectric Ceramics Lab Laser and Functional Materials Division Raja Ramanna Centre for Advanced Technology Indore452 013 India Chemical Treatment Laboratory Design and Manufacturing Technology Division Raja Ramanna Centre for Advanced Technology Indore452 013 India

The increasing demand of energy harvesting and wearable electronics applications requires the development of flexible and highly durable piezoelectric nanogenerators (PENG). In this work, We have fabricated flexible ZnO:PvDF based PENGs for vibrational energy harvesting and shoe insole pedometer applications. ZnO nanorods were grown by hydrothermal method and incorporated into PvDF matrixes in the concentration range of 5–15 wt%. These homogeneous ZnO:PvDF composite films were sandwiched between Al electrodes to realize flexible free standing PENGs. The open circuit voltage (voc), short circuit current (Isc) and instantaneous power density of PENGs increased from ~ 4 v, 0.4 µA and 1.6 µW/cm2 to ~ 14.6 v, 0.6 µA and 21.3 µW/cm2 respectively when ZnO nanorods concentration in PvDF increased from 0 to 10 wt% and decreased with further increase in ZnO nanorods concentration. The enhancement in output characteristics of ZnO:PvDF PENG with increasing ZnO concentration was attributed to β-phase crystallization of PvDF, which was confirmed by XRD and FTIR measurements. The deterioration in output characteristics beyond 10 wt% of ZnO nanorods concentration was explained considering the variation of dielectric constant and remnant polarization. The rectified output of the PENGs was effectively stored in various commercially available capacitors and used to power LEDs and stopwatch displays. The PENG with 10 wt% ZnO concentration was used to develop shoe insole pedometer which was interfaced with android based mobile application via Bluetooth. The shoe insole pedometer was successfully tested for 5000 steps at different walking frequencies ranging from 0.5 Hz to 2 Hz in the speed range of ~ 1.4 km/h to 5.5 km/h. This study not only gives an insight into the mechanism of ZnO:PvDF based PENGs but also opens up their potential in vibration energy harvesting and shoe insole pedometer applications. © 2023, The Authors. All rights reserved.

关键词： Zinc oxide

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Progress in the electrochemical reduction of CO₂ to formic acid: A review on current trends and future prospects

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JOURNAL OF ENvIRONMENTAL CHEMICAL engineering 2021年第6期9卷

作者： Duarah, Prangan Haldar, Dibyajyoti Yadav, v. S. K. Purkait, Mihir Kumar Indian Inst Technol Guwahati Ctr Environm Gauhati 781039 Assam India Karunya Inst Technol & Sci Dept Biotechnol Coimbatore 641114 Tamil Nadu India Indian Inst Technol Guwahati Dept Chem Engn Gauhati 781039 Assam India

The utilization of CO2 to produce formic acid (HCOOH) is regarded as an acceptable and efficient approach for mitigating the negative effects of gaseous emissions from chemical industries and other anthropogenic activities. Electrochemical reduction (ECR) is a method for converting CO2 to HCOOH in which electrocatalysts, electrodes, and electrolytes all play a vital role. Despite considerable advancements in CO2ECR, its efficiency is still hampered by a number of difficulties, including high electrocatalyst costs, selectivity toward HCOOH production, poor electrode surface area, and reactor mass transfer limitation. Numerous researches have been performed in recent decades to alleviate such constraints. The current review focuses on the progress in the production of HCOOH through CO2ECR. The involvement of the electrocatalyst, electrode and electrolyte in the ECR process is thoroughly examined. Furthermore, the impact of different parameters such as pressure, temperature, and reactor design are thoroughly analyzed. Further, the commercial aspects and techno-economic analysis of the utilization of CO2 are featured to highlight the process feasibility. Finally, this paper is concluded by discussing the challenges that are frequently encountered during the ECR process for HCOOH production with an aspiration of futuristic developments. The readers of this paper will be highly benefited by acquiring comprehensive knowledge on the ECR mechanism for HCOOH production.

关键词： CO2 reduction Formic acid Electrochemical reduction Electrocatalyst Advancements

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Reflection-mode virtual histology using photoacoustic remote sensing microscopy

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SCIENTIFIC REPORTS 2020年第1期10卷 1-13页

作者： Bell, Kevan Abbasi, Saad Dinakaran, Deepak Taher, Muba Bigras, Gilbert van Landeghem, Frank K. H. Mackey, John R. Reza, Parsin Haji Univ Waterloo PhotoMed Labs Dept Syst Design Engn E7-6416 200 Univ Ave West Waterloo ON N2L 3G1 Canada Univ Waterloo Dept Syst Design Engn IllumiSon Inc Waterloo ON N2L 3G1 Canada Univ Alberta Dept Oncol Edmonton AB T6G 1Z2 Canada Univ Alberta Div Dermatol Dept Med Edmonton AB T6G 2V1 Canada Univ Alberta Dept Lab Med & Pathol Edmonton AB T6G 2V1 Canada

Histological visualizations are critical to clinical disease management and are fundamental to biological understanding. However, current approaches that rely on bright-field microscopy require extensive tissue preparation prior to imaging. These processes are both labor intensive and contribute to creating significant delays in clinical feedback for treatment decisions that can extend to 2-3 weeks for standard paraffin-embedded tissue preparation and interpretation, especially if ancillary testing is needed. Here, we present the first comprehensive study on the broad application of a novel label-free reflection-mode imaging modality known as photoacoustic remote sensing (PARS) for visualizing salient subcellular structures from various common histopathological tissue preparations and for use in unprocessed freshly resected tissues. The PARS modality permits non-contact visualizations of intrinsic endogenous optical absorption contrast to be extracted from thick and opaque biological targets with optical resolution. The technique was examined both as a rapid assessment tool that is capable of managing large samples (>1 cm(2)) in under 10 min, and as a high contrast imaging modality capable of extracting specific biological contrast to simulate conventional histological stains such as hematoxylin and eosin (H&E). The capabilities of the proposed method are demonstrated in a variety of human tissue preparations including formalin-fixed paraffin-embedded tissue blocks and unstained slides sectioned from these blocks, including normal and neoplastic human brain, and breast epithelium involved with breast cancer. Similarly, PARS images of human skin prepared by frozen section clearly demonstrated basal cell carcinoma and normal human skin tissue. Finally, we imaged unprocessed murine kidney and achieved histologically relevant subcellular morphology in fresh tissue. This represents a vital step towards an effective real-time clinical microscope that overcomes the limitat

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Collaborative Intelligence: Challenges and Opportunities

Collaborative Intelligence: Challenges and Opportunities

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IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Ivan v. Bajic Weisi Lin Yonghong Tian School of Engineering Science Simon Fraser University Canada School of Computer Science and Engineering Nanyang Technological University Singapore Peking University China

This paper presents an overview of the emerging area of collaborative intelligence (CI). Our goal is to raise awareness in the signal processing community of the challenges and opportunities in this area of growing importance, where key developments are expected to come from signal processing and related disciplines. The paper surveys the current state of the art in CI, with special emphasis on signal processing-related challenges in feature compression, error resilience, privacy, and system-level design.

关键词： Privacy Conferences Collaboration Signal processing Acoustics Speech processing Collaborative intelligence

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Micro-EDM Machining With Copper Foil

Research Square

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Research Square 2021年

作者： Mouralova, Katerina Bednar, Josef Benes, Libor Prokes, Tomas Fries, Jiri Brno University of Technology Faculty of Mechanical Engineering Brno Czech Republic Jan Evangelista Purkyně University Faculty of Production Technologies and Management Ústí nad Labem Czech Republic Technical University of Ostrava Department of Production Machines and Design Ostrava Czech Republic

Electrical discharge die-sinking machining (EDM) is one of the indispensable unconventional technologies enabling the machining of all materials that are at least minimally electrically conductive. Due to the clear trend of miniaturization of products, it is necessary to ensure their quality and accurate production, also with the help of micro-EDM. It is the optical instruments used for testing car lights that contain these miniaturized parts necessary for the correct functioning of the device. For this reason, this study was performed, which focused on the production of a precise slot measuring 5000x170 µm in a copper foil with a thickness of 125 µm. The same copper foil was used as a tool, which represents an advance in the production of micro-parts. A design of experiment Box and Behnken Response Surface design was performed for a total of 15 rounds, monitoring the effect of machine setting parameters (Pulse current, Pulse on time and voltage) on responses in the form of Erosion rate, corner radius, slot length and width. Using multi-criteria optimization, the optimal setting of the machine parameters for the production of a given slit was determined, which is Pulse current = 2.1 A, Pulse on time = 40 µs and voltage = 238.8 v. © 2021, CC BY.

关键词： design of experiments

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Recent progress in bismuth-based high Curie temperature piezo-/ferroelectric perovskites for electromechanical transduction applications

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current OPINION IN SOLID STATE & MATERIALS SCIENCE 2022年第5期26卷

作者： Liu, Zenghui Wu, Hua Yuan, Yi Wan, Hongyan Luo, Zeng Gao, Pan Zhuang, Jian Zhang, Jie Zhang, Nan Li, Jingrui Zhan, Yage Ren, Wei Ye, Zuo-Guang Xi An Jiao Tong Univ Key Lab Minist Educ & Int Ctr Dielect Res Sch Elect Sci & Engn Elect Mat Res Lab Xian 710049 Peoples R China Donghua Univ Coll Sci Ren Min Rd 2999 Songjiang Shanghai 201620 Peoples R China Simon Fraser Univ Dept Chem LABS 4D Burnaby BC V5A 1S6 Canada Shaanxi Univ Sci & Technol Sch Elect Informat & Artificial Intelligence Xian 710021 Peoples R China

Piezo-/ferroelectric materials with high Curie temperature (TC) are widely needed in sensors, actuators and transducers which can be used for high-temperature (HT) electromechanical transduction applications. In recent years, remarkable progress has been made in bismuth-based piezo-/ferroelectric perovskite materials (BPPs). In this article, recent progress in high TC BPPs is reviewed. This review starts with an introduction to HT piezoelectrics and their applications. A detailed survey is then carried out on bismuth-based perovskites (BPs) with high TC. Material synthesis, doping effects and chemical modifications of the related solid solutions are examined. Based on this analysis, the structure-property relationship of these materials is established. In addition, recent developments of BPPs for HT electromechanical transduction applications are presented and evaluated. Lastly, some main existing issues are analyzed and their possible solutions are proposed. This article provides a comprehensive overview of the research and development of BPPs and offers some prospects towards making these materials a viable resource for the design and fabrication of electromechanical transducers with unique specifications, especially, high temperature, high frequency and high power, for a wide range of technological applications.

关键词： Bismuth-based perovskite High Curie temperature Piezoelectric and ferroelectric materials Electromechanical transduction applications

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Hexagonal Resonator Loaded Star Shaped Polarization Insensitive Compact Broadband Zero Indexed Nano-Meta Absorber for optical Region Applications: A Numerical Approach

Research Square

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Research Square 2021年

作者： Samsuzzaman, MD. Hossain, Ismail Hoque, Ahasanul Islam, Mohammad Tariqul Almutairi, Ali F. Universiti Kebangsaan Malaysia UKM Selangor Bangi43600 Malaysia Faculty of Computer Science and Engineering Patuakhali Science and Technology University Bangladesh Electrical Engineering Department Kuwait University Kuwait City13060 Kuwait Dept. of Electrical Electronic and Systems Engineering Faculty of Engineering and Built Environment Universiti Kebangsaan Malaysia Malaysia

Broadband response metamaterial absorber (MMA) remains a challenge among researchers. A nanostructured new Zero Indexed Metamaterial (ZIM) absorber is presented in this study, which is constructed with a hexagonal shape resonator for the optical region applications. The design consists of a resonator and dielectric layers made with tungsten and quartz (Fused), respectively. The proposed absorbent exhibits average absorption of more than 0.8972 (89.72%) within the visible wavelength of 450-600 nm and almost perfect absorption 0.99 (99%) at 458.54 nm. Based on computational analysis, the proposed absorber can be characterized as Zero Indexed Metamaterial. The developments of ZIM absorbers have demonstrated plasmonic resonance characteristics and a perfect impedance match. The incidence obliquity in typically the range of 0°–90° both in TE and TM mode with maximum absorbance is more than 0.8972 (~89.72%) and up to 35° angular stability,which is suitable for solar cell applications, like exploiting solar energy. The proposed structure prototype is designed and simulated by a study of microwave technology numerical computer simulation (CST) tools. Finite integration technique (FIT) and finite element method (FEM) is performed to data analysis in CST software, and HFSS also helps validate the numerical data of the proposed ZIM absorber. The proposed MMA design is appropriate for substantial amounts of absorption, wide-angle stability, absolute invisible layers, magnetic resonance imaging (MRI), color images, and thermal imaging applications. © 2021, CC BY.

关键词： Polarization

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