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Visualizing hypoxic modulation of beta cell secretions via a sensor augmented oxygen gradient

Microsystems & Nanoengineering 2023年第1期9卷 191-202页

作者： Kai Duan Mengyang Zhou Yong Wang Jose Oberholzer Joe F.Lo Department of Mechanical Engineering Bioengineering ProgramUniversity of Michigan at DearbornDearbornMI48128USA Department of Surgery/Transplant University of VirginiaCharlottesvilleVA22908USA

One distinct advantage of microfluidic-based cell assays is their scalability for multiple concentrations or *** scaling can be extremely powerful when combining multiple parameters and ***,in situ stimulation and detection eliminates variability between individual ***,conventional microfluidics must combat diffusion,which limits the spatial distance and time for molecules traveling through ***,we leveraged a multilayered microfluidic approach to integrate a novel oxygen gradient(0–20%)with an enhanced hydrogel sensor to study pancreatic beta *** enabled our microfluidics to achieve spatiotemporal detection that is difficult to achieve with traditional *** this device,we demonstrated the in situ detection of calcium,insulin,and ATP(adenosine triphosphate)in response to glucose and oxygen ***,insulin was quantified at levels as low as 25 pg/mL using our imaging ***,by analyzing the spatial detection data dynamically over time,we uncovered a new relationship between oxygen and beta cell *** observed an optimum oxygen level between 10 and 12%,which is neither hypoxic nor normoxic in the conventional cell culture *** results provide evidence to support the current islet oscillator *** future applications,this spatial microfluidic technique can be adapted for discrete protein detection in a robust platform to study numerous oxygen-dependent tissue dysfunctions.

关键词： hypoxic stimulation gradient

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Recycling of Magnesium Alloy Using the Gravity-Driven Multiple-Effect Thermal System (G-METS)

Recycling of Magnesium Alloy Using the Gravity-Driven Multip...

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Magnesium Technology Symposium held at the TMS Annual Meeting and Exhibition, 2024

作者： Mc Arthur Sehar, Daniel Telgerafchi, Armaghan Ehsani Iurkovskyi, Artem Opoku, Emmanuel Powell, Adam Materials Science and Engineering Program Department of Mechanical Engineering Worcester Polytechnic Institute WorcesterMA United States Department of Mechanical Engineering Worcester Polytechnic Institute WorcesterMA United States

ISBN: (纸本)9783031502392

MagnesiumMagnesium metal has been significantly used in commercial applications from automobiles to aluminum alloys to defense weaponry. The surge in structural usage of magnesium over the past years has been due to high strength and excellent stiffness-to-weight ratio. RecyclingRecycling magnesium scrap is a crucial aspect of the sustainability of the economy and environmental welfare. G-METS is an advanced distillationDistillation system used in the conversion of low-grade magnesium scrap into high-purityHigh-purity magnesium metal. This multiple-effect system uses the weight of magnesiumMagnesium as a compressor, to build pressure differences between each effect of the condenser-evaporator, modifying boiling points, and enabling transfer of vaporization enthalpy. This system is exceptionally efficient compared to the energy-intensive conventional distillationDistillation technique. This study compares experiments and models of one- and two-effect distillers. © The Minerals, Metals & Materials Society 2024.

关键词： Magnesium alloys

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Development and experimental studies of a light vehicle diesel after treatment system with DOC, DPF and urea SCR 1

Development and experimental studies of a light vehicle dies...

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1st International Conference on Materials Innovation in engineering and Technology, ICMIET 2024

作者： Thangapandian, P. Paulsingarayar, S. Chandraprakash, R. Seenivasan, S. Kannan, I. Vimal Siddeshwar, S.A. Department of Mechanical Engineering Rathinam Technical Campus Coimbatore641021 India Department of Mechanical Engineering NPR College of Engineering and Technology Dindigul Natham624401 India Department of Robotics and Automation Engineering Dhaanish Ahmed Institute of Technology Coimbatore641 105 India Department of Mechanical and Automation Engineering Sri Sai Ram Engineering College West Tambaram Chennai600 044 India

Strict adherence to pollution limits poses a risk to light-duty diesel engines due to challenges in post-treatment procedures, product limitations, and emission criteria. This paper aims to determine the underlying principles for the technological development of an after-treatment technique that incorporates a diesel oxidation catalyst (DOC), catalytic Diesel Particle Filter (DPF), urea injector, and catalytic urea selective reduction (SCR). Implementing this selective catalytic reduction (SCR) technique would greatly enhance the catalyst's ability to convert NOx by regulating the evaporation of urea and avoiding a decrease in exhaust temperature and mixing efficiencies. Moreover, the uniformity of the NH3 concentration distribution over the catalyst surface is advantageous. This study explored the concept of an electrically evaporated urea-dosing device. The investigation revealed that heated urea had a beneficial effect on improving the elimination of NOx from both continuous and intermittent motor operations before its application to the gas exhaust. The cylindrical urea evaporative heating chamber was equipped with a venturi jet that directed urea vapour down the exhaust drain. The urea solution dosing technique, administered by spraying, was a customised method more advantageous than the conventional liquid dosage system. © 2024 Institute of Physics Publishing. All rights reserved.

关键词： Selective catalytic reduction

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Assess the Level of Temperature Uniformity in Intermediate Level Incubators Type Incandescent Lamp and Heater Plate 3rd

Assess the Level of Temperature Uniformity in Intermediate L...

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3rd International Conference on Experimental and Computational Mechanics in engineering, ICECME 2021

作者： Riswandha, Ditya Syuhada, Ahmad Hamdani of Mechanical Engineering Study Program Department of Mechanical and Industrial Engineering Faculty of Engineering Universitas Syiah Kuala Banda Aceh Indonesia

ISBN: (纸本)9789811936289

One of the business activities favored by the villagers is poultry farming. This happened because the harvest period is fast and the market is easy, especially for public consumption in the province of Nanggroe Aceh Darussalam. Due to the large number of people who are trying to raise ducks, chickens, and laying eggs, problems have arisen with the provision of these poultry seeds. So far, poultry seeds in the Aceh Province have been obtained from a small portion of the populationAcehnese themselves and the rest were imported from North Sumatra. This causes the fluctuating supply of seed poultry which will eventually disrupt the community's poultry farming business in Aceh Province. Seeing these problems, this research wants to produce a multilevel incubator heating system that maintains a uniform temperature for better incubator efficiency. The test is carried out by paying attention to the temperature distribution in the egg incubator. Thus, measuring the distribution temperature with a value range of 37 °C–38 °C at certain points through the test channel is the main thing that must be done. The variation in this research is the number of incandescent lamps/heating plates (4 and 6) which differs whether or not the zinc plate is under the incandescent lamp/heating plate with a power of 100 and 112 Watts for each heater. The heater in the incubator room will turn on at 37 °C and will turn off automatically at 38 °C due to the influence of the thermostat equipment. After testing, the temperature was 0.7 °C for 4 (four) heating plates without using a zinc plate under the heating plate and 0.8 °C for 4 (four) incandescent lamps without using a zinc plate under the incandescent lamp. However, there is a small comparison, namely 0.4 °C for 6 (six) heating plates using a zinc plate under the heating plate and 0.5 °C for 6 (six) light bulbs using a zinc plate under an incandescent lamp. Also 96% test results with various methods. It is a good heat transfer and efficient pro

关键词： Incandescent lamps

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Simulation of Data Acquisition System Using SimulIDE, Virtual Serial Port and Python 9

Simulation of Data Acquisition System Using SimulIDE, Virtua...

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9th International Conference on Education and Technology, ICET 2023

作者： Puji, Muhammad Nurul Astuti, Winda Binus Aso School of Engineering Bina Nusantara University Automotive and Robotics Engineering Program Computer Engineering Department Jakarta Indonesia

ISBN: (纸本)9798350358292

Data acquisition systems are commonplace in the current era of digitalization and Industry 4.0. These systems are typically used to obtain data from sensors, whether analog or digital, which is then stored for processing in subsequent stages. However, the implementation of hardware for creating data acquisition systems can be challenging due to constraints such as laboratory facilities, budget limitations, and other factors. Therefore, in this research, SimulIDE simulation software was employed to simulate electronic components and the Arduino Uno. To make this virtual Arduino appear as a physical one to the host computer, PyVirtualSerialPorts was used as a virtual serial port. The data acquisition system was created using Python programming with several key features: it can store data in CSV format, present data plots and graphs, and display the frequency spectrum of signals. The system achieved a sampling speed of 1000 data points per second, with input signals limited to a maximum of 10 Hz. This study also shows that signal distortion can occur due to excessively frequent data plotting and Fast Fourier Transform (FFT) processing. Therefore, the use of SimulIDE simulator, virtual serial port, and Python can be utilized in the learning process of a simple data acquisition system. © 2023 IEEE.

关键词： Python

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An Electrochemical HbA1c Immunosensor With a Simple Electrode of Gold Nanoparticle Monolayer

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IEEE Sensors Journal 2023年第15期23卷 16579-16584页

作者： Tseng, Chun-Chiang Lin, Ying-Ting Wang, Gou-Jen National Chung-Hsing University Department of Mechanical Engineering Taichung40227 Taiwan National Chung-Hsing University Program in Tissue Engineering and Regenerative Medicine Taichung40227 Taiwan National Chung-Hsing University Department of Mechanical Engineering The Graduate Institute of Biomedical Engineering Taichung40227 Taiwan

This study developed a novel electrochemical glycosylated hemoglobin (HbA1c) immunosensor. Polyethylene terephthalate (PET) was used as a substrate. After gold (Au) film sputtering on the PET surface, 1,6-hexanedithol with thiol groups on both terminals was used as an intermediary to attach a monolayer of uniformly distributed Au nanoparticles (AuNPs) to the Au thin film to form a nanostructured electrode. HbA1c antibodies were successfully immobilized on the AuNP monolayer via the self-assembled monolayer (SAM) approach. To mimic a real clinical detection environment, a calibration curve for HbA1c detection was performed in a mixture solution containing heparin sodium, red blood cell (RBC) lysis buffer, artificial human serum, and hemoglobin. The experimental results revealed that the proposed HbA1c immunosensor detected HbA1c in a linear range from 2500 to 10 000 ng/mL with a limit of detection of 2253 ng/mL. The developed HbA1c-sensing chip offers the advantages of simple operation, low cost, short detection time, and provides high feasibility for clinical application. © 2001-2012 IEEE.

关键词： Gold nanoparticles

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AN IMPROVED AND ENHANCED DEPTH MAP APPROACH FOR OBSTACLE DETECTION IN UNKNOWN ENVIRONMENTS FOR REACTIVE AUTONOMOUS MOBILE ROBOTS

AN IMPROVED AND ENHANCED DEPTH MAP APPROACH FOR OBSTACLE DET...

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ASME 2024 International mechanical engineering Congress and Exposition, IMECE 2024

作者： Raju, Vomsheendhur Selekwa, Majura F. Mechatronics and Robotics Laboratory Department of Mechanical Engineering North Dakota State University FargoND United States

ISBN: (纸本)9780791888636

Interest in autonomous vehicles has attracted research into developing better navigation systems. Autonomous navigation systems guide unmanned vehicles to traverse any environment without human intervention;they require clear knowledge of the environment to make correct decisions. Information about the environment can be obtained from either ranging or vision sensors. Although ranging sensors such as LiDARs, radars, or sonars can detect the presence and location of obstacles, they don’t provide any information on whether the obstacles are traversable. On the other hand, vision sensors produce images similar to how human eyes perceive the environment, which can be processed to determine whether the sensed obstacle is traversable. Since vision sensors are light, less costly, and consume low power compared to LiDARs or Radars, there is an increasing interest in using them in autonomous navigation of unmanned ground vehicles. The main limitation of vision sensors for this purpose is their failure to directly identify the locations of the obstacles. Often, the location is determined by using a depth map, which is not always accurate and can be very computational. This paper proposes a new method of processing a depth map with improved accuracy. The depth of the closest objects to the stereo camera is extracted using the horizontal and vertical field of view of the sensor. It is further enhanced using morphological operations and the P-Tile segmentation technique to segment the obstacle(s) from its background and noise. This approach generates a denser map without any discontinuities, which leads to improved accuracy in locating close-by objects at less computational cost. Information from this depth map can be used as a low-cost alternative to ranging information in the navigation system for ground vehicles. Copyright © 2024 by ASME.

关键词： Stereo image processing

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Real-Time Geometric Joint Uncertainty Tracking for Surgical Automation on the dVRK System

Real-Time Geometric Joint Uncertainty Tracking for Surgical ...

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2024 IEEE International Conference on robotics and Biomimetics, ROBIO 2024

作者： Li, Bin Lin, Hongbin Zhong, Fangxun Liu, Yunhui T Stone Robotics Institute The Chinese University of Hong Kong The Department of Mechanical and Automation Engineering Hong Kong

ISBN: (纸本)9781665481090

Accurate control of surgical robotics under uncertainty is crucial for achieving surgical autonomy. This uncertainty arises from sensor or model inaccuracies in surgical platforms, e.g., dVRK system, where joint bias in positioning and complex transmission effects caused by backlash and cable stretch. Previous approaches usually rely on depth sensors or additional offline calibration steps, making them difficult to deploy in real-world laparoscopy surgeries. In this paper, we propose a real-time geometric approach for calibrating joint errors on-the-fly combined with geometric features. An efficient visual detector is employed to identify the shaft mask and wrist keypoints. Based on the extracted features, we introduce a geometric model to recover the shaft axis pose and determine the first two joints uncertainty. Additionally, we develop a geometric model for wrist joints in projection space, calibrating remaining joint uncertainty through spatial geometry and the analytical structure of dVRK platform. Experimental results in simulation show that our approach significantly reduces joint error from 15° to 0.02°, with end-effector pose accuracy improving from centimeter to sub-millimeter level. This greatly enhances the accuracy and success rate of surgical automation. We also demonstrate robust control performance in diverse surgical tasks, highlighting the effectiveness of our geometric model in achieving accurate control despite joint offsets. © 2024 IEEE.

关键词： End effectors

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Manufacturing process design for cellular structure used as impact energy absorbers 4

Manufacturing process design for cellular structure used as ...

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4th International Symposium on Advances and Innovation in mechanical engineering, ISAIME 2023

作者： Komara, Asep Indra Setiawan, Rachman Budiwantoro, Bagus Doctoral Program of Mechanical Engineering Faculty of Mechanical and Aerospace Engineering Institut Teknologi Bandung Bandung Indonesia Faculty of Mechanical and Aerospace Engineering Institut Teknologi Bandung Bandung Indonesia Manufacturing Design Engineering Department Politeknik Manufaktur Bandung Bandung Indonesia

The application of passive safety technology in vehicles is generally through impact-absorbing structures. This technology has been widely applied to trains, planes, and cars to protect passengers from fatal accidents. Cellular structures are defined by a unit cell that combines material, space, and unit cell repetition to obtain a large structure. It is selected as the base structure of the impact energy absorber for its potentially high specific energy absorption (SEA]. Such a structure poses a challenge in its manufacturing method. This study examines alternative manufacturing processes for cellular structures designed as impact absorbers, and then selects and develops an effective and efficient manufacturing method to produce these cellular structures. Several alternative manufacturing methods were chosen to exercise the use of a combined plaster molding technology and additive manufacturing for prototyping. Manufacturing process simulation studies were conducted using Altair Inspire Cast software to determine the success of the casting process. The final stage is to carry out the process of making cell structures and evaluating the results. This work results in an effective manufacturing process design to be implemented throughout the production stage. Furthermore, for mass production, mold patterns may be replaced by using injection molding. © 2025 Institute of Physics Publishing. All rights reserved.

关键词： Injection molding

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Coverage Path Planning of Agricultural Spraying Drones with Graph Convolutional Network 12

Coverage Path Planning of Agricultural Spraying Drones with ...

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12th RSI International Conference on robotics and Mechatronics, ICRoM 2024

作者： Khaloujini, Amirmasood Talaeizadeh, Amin Taheri, Alireza Alastya, Aria Advanced Research Lab for Control and Agricultural Robotics Sharif University of Technology Social and Cognitive Robotics Lab. Department of Mechanical Engineering Tehran Iran

ISBN: (纸本)9798331529734

Optimal route planning for autonomous robots is a crucial element of contemporary agriculture, especially for activities like spraying and pollination. This paper presents a Graph Convolutional Network (GCN) model especially developed to address the Coverage Path Planning (CPP). The aim of this paper is to convert the CPP problem into a Traveling Salesman Problem (TSP), so that by solving the TSP using the proposed neural network, an optimal route can be extracted for each agricultural field in the shortest possible time and with sufficient accuracy, ensuring full coverage of the field's area. The proposed model is a GCN, augmented with a transformer layer and a Multi-Layer Perceptron (MLP), was trained using datasets produced by a Genetic Algorithm (GA) Method. The model obtained a network error of 0.12 while solving TSP cases with 20 points. It showed robust generalization skills, as evidenced by validation and test errors of 0.1261 and 0.1264, respectively. Significantly, the GCN model reduces the solution time to approximately one-tenth compared to conventional approaches, a benefit that increases as the number of points increases. The effectiveness of the model in producing ideal coverage routes highlights its potential for wider use in optimization and coverage path planning, especially in dynamic and extensive agricultural environments. © 2024 IEEE.

关键词： Traveling salesman problem

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