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Lower extremity exoskeletons augment ability of walking, sitting and standing upright with a pair of robotic legs that ambulates the user with mobility disorder. As a mobility aid, being lightweight and compact can highly increase usability by allowing users to navigate through narrow passages. This paper summarizes the design of low profile actuators designed for minimally actuated exoskeleton, a lightweight and low profile powered medical exoskeleton developed in Robotics and Human Engineering Laboratory at UC Berkeley. An analytical method for designing low profile BLDC actuation units, critical hardware design aspects, and initial performance measurements are discussed. A set of pancake DC actuation units was designed, manufactured, assembled, and integrated into a lower limb medical exoskeleton. This exoskeleton was tested by a male 28-year-old paraplegic test pilot with injury level of T12.Copyright © 2015 by ASME

Our experimental research on fatigue performance of stainless steels and transferability of laboratory data to plant operational conditions focuses in niobium stabilized stainless steel (1.4550, X6CrNiNb1810mod) taken from a pipe manufactured as primary piping for a German NPP Good fatigue performance both in air and in PWR water was reported in previous PVP papers. The NUREG/CR-6909 report proposes Fen factors based on stroke controlled experiments in hot water for non-stabilized steels. Since PVP2013-97500 we have new data in 200°C PWR water to compare with predictions by NUREG/CR-6909. Our strain controlled tests in 325°C and 200°C PWR water give longer lives resp. smaller Fen factors. For the slowest tested strain rate 4·10−6 in 325°C water the prediction according to NUREG/CR-6909 goes just below the current ASME design curve, but our results remains well above. Including also the relevant design temperature effect, our result Fen = 4 is well below the predicted Fen = 14,5. The gap is smaller for higher strain rates and low Fen values. Simplified simulations of fatigue transients combined with normal operation indicated that relevant loading patterns as hold-time effects may result to notably longer lives than in standard laboratory tests. A concern was raised on transferability of data to thermal transients separated with months of normal operation. Cyclic strain (transients) followed by hot holds (normal operation) lead to time and temperature dependent hardening with reduction in cyclic plastic strain and fatigue usage, i.e. extension of life. This paper reports new data, challenges met and our progress towards developing realistic design factors for effects both reducing and extending fatigue endurance in nuclear power plant operational conditions.

Piezoelectric devices are among the most efficient and reliable solutions for power harvesting from environment vibrations. Considerable effort has been devoted recently in the engineering community towards reducing the size and increasing the power density of these generators at the micro level. The objectives of this paper are to identify commercially available materials and to determine the geometrical configuration best suited for energy harvesting applications by assessing their performance when used in a cantilever beam micro-generator with a fixed volume. To achieve this objective, a comprehensive database with properties of commercially available piezoelectric materials is first established. Then electro-mechanical simulation is carried out to study the changes in device performance with respect to variations in the geometrical configuration for a vibrating beam with a fixed end and a mass attached at the free tip. Once the materials and geometrical configuration providing the highest power output are identified, other aspects important to system implementation are discussed such as feasibility of fabrication at the desired scale and integration with the electronic circuitry. The results obtained provide guidelines for designing and realizing reduced scale cantilever-beam piezoelectric harvesters employing high performance, commercially available materials.Copyright © 2012 by ASME

When the ASME Code fatigue curves (S-N curves) are used in the assessment of high frequency cyclic stresses (such as those produced by flow-induced vibrations), the question arises as to the need for an E correction (i.e., multiplying the calculated cyclic stress by the ratio of the E value at the room temperature and the E value at the temperature used in the stress analysis). This question becomes significant for materials such as stainless steels when the two sets of S-N curves up to the 2007 Edition of the Code [1] are specified: i) the first curve covered the cyclic range of 10 to 106 cycles and specified an E value. This curve covered mostly the strain controlled fatigue data for which the correction for E is required. ii) The second curve covered the cyclic range of 106 to 1011 cycles and didn’t provide a specific E value. This curve covered mostly the load controlled fatigue test data for which the correction for E is not required since the stress was independent of E (stress was either P/A for axial loading or Mc/I for bending). However the 2010 and subsequently the 2013 Editions of the Code [2] combined the two curves into a single curve with a cycle range of 10 to 1011 cycles with E value specified at room temperature. This means that the E correction applies across the board for the entire cyclic range of 10 to 1011 cycles including the high cycle end where the test results are independent of E. The inclusion of the E correction for the high cycle fatigue range presents a problem for the evaluation of components with vibratory loading. The present paper describes the results of a thorough review of the past technical basis papers for the ASME Code S-N curves and examines the necessity for E correction at the high cycle end of the Code S-N curves for stainless steels.Copyright © 2015 by ASME

Every day, people are presented with tasks that are completed with very little mechanical effort such as turning a door knob, turning a screw driver, and grabbing a cup to move it to a new location and/or orientation. These tasks are often overlooked in the mechanical study of human movement due to the fact they carry with them very little biomechanical costs or effort. However, from a cognitive standpoint, these tasks carry high complexity. For example, the simple task of grabbing a cup and flipping it over is very easy mechanically and can be effortlessly achieved by a two year old. However, it is impossible to predict or simulate this motion without major intervention in the form of explicit constraints defining the task. The model itself cannot decide in which orientation the hand should assume in order to grasp the object. Also, it cannot decide where on the object the hand should be placed. These aspects must be assumed by the researcher and constrained in the formulation. In other words, digital human models, such as optimization-based motion prediction models, are unable to plan actions. This implies that for each task, a unique optimization formulation is needed in order to predict the motion/posture needed to complete each task. This paper presents a new method for task planning prediction within optimization based posture and motion prediction. It provides a new single optimization formulation that allows for the prediction of multiple unique manual manipulation tasks. The method is based on observations made from experimental studies on cognitive motor planning.Copyright © 2013 by ASME

Natural gas accepted into the pipeline at receipt points is subject to gas quality specifications to ensure that downstream laterals and mainlines are not subjected to operational upsets, and that the integrity of the pipeline and related facilities is not compromised. One of the specifications is the maximum hydro-carbon dew point (HCDP) at the pipeline operating pressure. Occasionally, gas plants encounter operational upsets that result in a higher HCDP. If the HCDP exceeds the ground temperature, condensation of heavier hydrocarbon can potentially occur along the lateral. Ideally, after an upset has been detected and the producer has been shut in, the lateral would be pigged to remove the condensed hydrocarbons. However, if the lateral is unpiggable, the only way to remove the liquids is to evaporate them into a flow of dryer gas. The present paper compares two potential courses of action which may be taken after a high HCDP is detected at a receipt point on an unpiggable line: (a) flowing dry gas from the producer after the source of upset is corrected, or (b) pulling dryer gas back from the operator’s mainline through the lateral to the producer. In order to determine the most appropriate course of action for a given upset, the state of the lateral during and after the upset must first be accurately quantified. In the present paper, the state was modelled based on the governing equations of fluid flow including heat transfer and condensation, the GERG-2008 equation of state, and empirical liquid-hold-up equations. The effect of flow parameters (e.g., gas composition, lateral elevation profile, ground temperature, etc.) on the upset severity is explored. Subsequently, models for forward flow and pull back are presented, and the criteria for selecting when either course of action is appropriate are discussed.

An O-ring made of rubber exhibits excellent sealing performance with a wide range of applications. The highest sealing pressure can be up to 400MPa. The temperature ranges from −60 °C to 200 °C and the medium is low-corrosiveness. This paper proposes an O-ring sealing device for high pressure vessels, which can be opened and operated outside a cylinder. There are no bolts bearing the axial stress under the internal pressure load, and the sealing efficiency of this device is guaranteed by the dimension chain. The whole sealing device has no threaded connections except for the oriented screw which does not bear load under the working conditions. Based on this newly developed sealing device, a high pressure vessel with the design pressure of 60 MPa and the internal diameter of 700 mm used to simulate 6000 m deep sea environment is developed and investigated. This paper firstly introduces the rationale behind the design of the sealing structure for this high pressure vessel, and then discusses a finite element model of the cylinder end for this high pressure vessel and the stress classification method which is used to evaluate the safety of the critical sections. Lastly, the paper presents a set of experimental devices and a series of experiments which were carried out. The results show that the proposed sealing structure can be used in high pressure vessels. The results also verify the assumption of triangle contact pressure distribution between the shear ring and the cylinder end. It is hoped that this study will be of interest and value to researchers when they design the similar structures in the future.Copyright © 2013 by ASME

Sustainable development has become an increasingly common topic of both day-day conversations and in discussions about professional responsibility. In recent years, most of the professional engineering societies have moved to incorporate language about environmental responsibility, including sustainable development, into their codes of ethics. The ASME Code, for example, states that “Engineers shall consider environmental impact and sustainable development in the performance of their professional duties” (2). Despite this increased focus on sustainable development, it remains a nebulous concept at both a theoretical and practical level. Few engineers would deny that they have a responsibility to the environment. Ask those same engineers what this responsibility means in practice and you are likely to get a variety of answers; most of which will probably be on the vague side. Of course, variation and generality are not always negative features of a professional ethic. Nevertheless, it is important to get more precise about what sustainable development looks like in practice. In this paper, I will analyze ASME’s prescription that mechanical engineers consider their impact on the environment. I will examine how this prescription fits into the ASME Code as a whole. I will then survey several definitions of sustainable development; exploring challenges along the way. From here, I will begin developing a functional definition of sustainable development. In doing so, I will attempt to balance the demands of the principle of conservatism when spelling out professional obligations with those of moral leadership. The goal is to provide a useful and rigorous definition of sustainable development for practicing engineers. If am successful in this, this definition will lead to an operational understanding of sustainable development.

Recent tragic accidents have focused attention on the dangers of unmonitored helicopter dynamic assemblies. Methods are available to monitor the entire power train from the engine to the rotor. Apart from the obvious safety advantages, such systems offer the additional benefits of increased availability, a planned maintenance schedule and a reduction in life cycle costs. Historically, monitoring systems have evolved from isolated processing units, each performing single functions. Hawker Siddeley Dynamics Engineering Ltd, in conjunction with Stewart Hughes Ltd is developing a modular and integrated health and usage monitoring system. After a brief discussion of health monitoring equipment evolution, this paper focuses on the practical application of the techniques required to ensure the health of the modern helicopter.

Lab-grown diamond heat spreaders are becoming attractive solutions compared to traditional copper heat spreaders due to their high thermal conductivity, the ability to directly bond them on silicon, and allow for an ultra-thin silicon layer. Researchers have developed various thermal models and prototypes of lab-grown diamond heat spreaders to evaluate their cooling performance and heat spreading ability. The majority of existing thermal models are built using finite-element method (FEM) based simulators such as COMSOL and ANSYS. However, such commercial simulators are computationally expensive and lead to long solution times along with large memory requirements. These limitations make commercial simulators unsuitable for evaluating numerous design alternatives or runtime scenarios for real-world high-performance processors. Because of this modeling challenge, none of the existing works have evaluated the thermal behavior of lab-grown diamond heat spreaders on real-world high-performance processors running realistic application benchmarks. Recently, we have developed a parallel compact thermal simulator, PACT, that is able to carry out fast and accurate steady-state and transient thermal simulations and can be extended to support emerging integration and cooling technologies. In this paper, we use PACT to evaluate the steady-state and transient cooling performance of lab-grown diamond heat spreaders against traditional copper heat spreaders on various real-world high-performance processors (e.g., Intel i7 6950X, IBM Power9, and PicoSoC). By using PACT with architectural performance and power simulators such as Sniper and McPAT, we are able to run transient simulations with realistic benchmarks. Simulation results show that lab-grown diamond heat spreaders achieve maximum temperature and thermal gradient reductions of up to 26.73 °C and 13.75 °C when compared to traditional copper heat spreaders, respectively. The maximum steady-state and transient simulation times of PACT for the real-world high-performance chips and realistic applications used in our experiments are 259 s and 22 min, respectively.

Considering “Pipeline Industry’s Need of the Hour - Self Reliance and Emerging Technology Trends” as theme of pipeline conference, my submission of paper is on several use cases on technology and innovation for pipeline’s different life cycle phases. There are continual developments in pipeline industry and several of technologies were successfully implemented or under consideration phase for implementation for pipeline industry. In all phases of pipeline lifecycle of material management, project implementation as well in Operation & Maintenance (O&M) of pipeline. Several technological changes as well several of innovations in existing systems are of extensive use for enhancing pipeline safety, reliability, monitoring system as well ease of operations and maintenance. Many of systems been used for other purposes and are of great use for pipelines. This paper discusses on few of such technologies and their implementation for pipelines.

Designing commercial aircraft to use liquid hydrogen (LH2) is one way to substantially reduce their life-cycle CO2 emissions. The merits of hydrogen as an aviation fuel have long been recognized, however, the handling of a cryogenic fuel adds complexity to aircraft and engine systems, operations, maintenance and storage. The fuel tanks could account for 8–10% of an aircraft’s operating empty weight, so designing them for the least added weight is of high significance. This paper describes the heat transfer model developed in the EU Horizon 2020 project that is used to predict heat ingress to a cylindrical tank with hemispherical end caps with external foam insulation. It accounts for heat transfer according to the state of the tank contents, the insulation material properties, the environment, and the dimensions of the tank. The model also estimates the rate of pressure change according to the state of the fuel and the rate at which fuel is withdrawn from the tank. In addition, a methodology is presented, that allows for tank sizing taking into consideration the requirements of a design flight mission, the maximum pressure developed, and the fuel evaporated. Finally, the study demonstrates how to select optimal insulation material and thickness to provide the lightest design for the cases where no gaseous hydrogen is extracted, and where some hydrogen gas is extracted during cruise, the latter giving gravimetric efficiencies as high as 74%.

In the recent years, the materials composing the traditional of aircrafts are being progressively replaced with lower density materials, as the Reinforced Plastics. The same trend has been highlighted in the Automotive field to assess the reduction of fuel consumption and CO2 emission. In order to achieve an optimization of maintenance a variety of on-board systems has been applied for on-line SHM based on piezoelectric transducers earned a particularly high interest for continuous monitoring on metallic and composite structures. The application of this system in automotive could enhance passenger safety, through the monitoring of the vehicle composite material structure health status. In this paper, six mathematical models for evaluating the electrical response of piezoelectric sensors have been implemented, with the aim of selecting the most effective model for damage identification. Experimental tests were carried out on three types of simpler specimens of different geometries made of different materials (steel, aluminum and carbon fiber). A correlation study has been carried on in order to support the positioning of sensors. The proposed numerical-experimental methodology is an essential foundation for the introduction of monitoring systems based on piezoelectric transducers in the Automotive sector.

Active aerodynamics is a promising technology to improve vehicle performance and efficiency, but so far in the automotive field the actuation methods suffer with several drawbacks that jeopardize its functioning and broad implementation. Morphing wings represent a technology already studied for aerospace applications that could help overcoming some of those issues. This paper proposes a piezoelectric transducer actuation for a composite material automotive wing and seeks to validate it through virtual models and physical tests. Experimental validation with a 3D-printed simplified wing profile confirms the feasibility of the technology and helps determining the best position for the piezo actuator. Furthermore, a FEM model is presented, where the piezo effect is simulated through a thermal analogy. An optimization of the composite stacking sequence is performed to maximize the trailing edge displacements, and its results are compared with the deflection caused by aerodynamic loads observed in the wing. The displacement of the trailing edge is in the order of tenths of a millimeter, even though further investigations are necessary to improve overall impact of the solution the preliminary results are promising.

In the current paper the reliability of spring interconnections for the use in automotive applications was investigated. A commercially available connector was used for contacting a piezo-jet printed silver pad on polycarbonate. The structures were tested using vibration tests at three different temperatures (−25°C, 25°C and 85°C) and measured using four-point probe measurement system and white light spectrometry. The obtained results showed the reliability of the printed structure and the contact, despite of the contact resistance change. The reasons of this change and experimental results are discussed in the paper. The investigations described in the paper provide an initial approach to the development of spring interconnections for printed electronics.

In the paper, a new test bench for characterization and durability assessment of multi disc wet clutches for motorbike applications is presented. The design of the new test bench is inspired by the current SAE standards J2490 and J286 that refer to the testing of friction material for automatic transmissions wet clutches. Differently from the test bench described in the two standards, which is mainly designed to test the friction material, the test bench presented in this paper has been designed for testing the whole clutch, comprising all discs and the actuation mechanism. The lubrication system of the clutch utilized on the test bench is very similar to the one present on the actual motorbike. The design and instrumentation of the new test rig is analysed and discussed in the paper. The test bench has been used for the characterization of different motorbike clutches. The bench has proved to be able to measure the clutch characteristic for different temperatures and clutch wear levels. A very good repeatability of the tests has been achieved allowing for a comparison of different clutches design, friction material properties and operating conditions (temperature, ..). Some experimental results are presented and discussed in the paper.

Additive manufacturing (AM) processes are gaining popularity and are currently used in many research activities including the biomedical applications, the automotive industries and the aerospace. Laser powder bed fusion (LPBF) is an important AM process. Metallic LPBF process is experiencing significant growth, but one of the difficulties facing this growth is limited knowledge of its dimensional and geometrical performances, in addition to the inability to predict it. In this paper, we present the dimensional deviations of some LPBF-manufactured parts selected for this investigation. a uniform method was developed regarding relevant test specimens to examine dimensional deviations in order to derive dimensional tolerance values. The manufactured test specimens were measured to examine the process dimensional deviations behavior. These parts were manufactured from AlSi10Mg powder using an EOSINT M280 printer. The results show possible dimensional tolerance values that were classified from IT1 to IT11 according to the international standard ISO 286.

The geometric shapes of coils influence the performance of a 3D IPT system. In this paper, we proposed a 3D coil design method based on (3D) printing electronics. Given a 3D transmitter coil, the center position of the receiver coil is estimated as a random seed position in the corresponding 3D surface first. At this position, we use the heatmap method with electromagnetic constraints to iteratively extend the coil until the desired power can be transferred via the coil. For each extension of the coil, i.e. a new turn, the shape of the coil is optimized by calculating the convex hull of the new turn in the 2D projection plane. Using this method, we are able to generate a receiver coil to transmit “just enough” power at a given seed position. Then, by fixing the receiver coil, the 3D shape of the transmitter coil can be optimized as well. This zig-zag optimization process iterates until there are few changes of the position and 3D shapes in the iteration. Experiment results with Ansys Maxwell verified the effectiveness of the proposed 3D coil design method, and highlighted possible future research directions as well.

A substantial part of the global energy mix depends upon fossil fuels that needed to be reduced to overcome the pollution and environment-related challenges. This has directed the world to shift the energy mix towards renewable energy technologies. Among the development in renewable energy technologies, the development of solar tower power plant is an active research topic. Over the past decade, advances in computers and simulation software systems have greatly expanded their use in design and development, which can facilitate the engineering activities of solar tower power plants. However, an important limitation is the visualization of three-dimensional geometrical design data onto two-dimensional computer screens. VR technologies are a great means in the visualization of 3D data. Therefore, this article attempts to illustrate a concept for the application of VR technologies in the development of solar tower power plant and lists down relevant support scenarios. The main focus of the paper is on analyzing the efficiency of the VR technology used in the design of solar tower power plants and learning from the experience gained in this process. A discussion about further scenarios ranging from on-site visualization of solar tower power plant infrastructure, installation and repair, cleaning and maintenance, etc. is included as well as future directions are pointed out. The demonstrator part consists of an Android Smartphone-based VR application and an HMD based VR application. Furthermore, a brief comparison of both the applications as well as of HMD and sVR is also provided.

The adoption of additive manufacturing methods is becoming prevalent in industry. Socio-economic trends seek more customization and sustainability in production. An increase in unique service components will warrant the need for more flexible repair methods. This is particularly important for components that are difficult to access or disassemble — thus requiring an on-site repair. This paper introduces the use of 3D printing pens as a means to perform repair to additively manufacturing components. A study was conducted to assess the feasibility of using a 3D printing pen in maintenance, repair and overhaul (MRO) applications on polymer-based service products. A series of tensile tests were conducted on printed specimens, pre- and post-repair, to examine the tensile retention of the mended region. Results indicate significant retention in tensile strength in the mended specimens, supporting the notion of the pens relevance in repair and overhaul applications. Specimens that fractured within the repair region were seen to have retained (81 ± 10) % of their original tensile strength while specimens that fractured outside the region retained (86 ± 4) %. Considering the limited control of the study, results acquired encourage further analysis of the underlying mechanisms in the process, with the intent to more efficiently exploit this approach for practical structure-based repair applications.

Social Impact has been widely discussed by the engineering community, but studies show that there is currently little systematic consideration of the social impact of products in both academia and in industry beyond social impacts on health and safety. This paper illustrates how Failure Mode and Effect Analaysis (FMEA) style analysis can be applied to evaluating the social impact of products. The authors propose a new method titled Social Impact Effects Analysis (SIEA), describe how it is performed, and explain the benefits of performing SIEA.

System Engineering education typically includes content to help students learn to design and engineer large, complex systems in a structured way. In this paper, we describe the outcomes of introducing a human-centered design tool, the Inspiration Design Toolkit (IDT), to encourage students to think non-linearly. The IDT is an educational resource consisting of a deck of illustrated cards that contain provocative questions, reflection messages and icons, applicative examples, and key takeaways on microlearning units. The aim of the IDT is to improve the participants’ learning experience and course engagement, increase opportunities for them to interact with their peers and teaching team, enable them to practice and reinforce the concepts through the creation of their own IDT cards, and share the cards in the discussion to increase learners’ engagement with course material and peers. We designed the IDT for an MIT online course on System Thinking. We collected, analyzed, and synthesized qualitative and quantitative feedback from 171 course participants. Our findings suggest that IDT provides learners with a digital asset that allows them to reinforce and recall the course takeaways, and apply them to other contexts. For future research, we want to understand how learners like and use IDT through demographic differences and preferred self-identified learning styles. We discuss how these findings may help educators consider critical design principles and for creating a digital self-learning toolkit connected to the course content and increasing its content adaptability.

Approximately one-third of anthropogenic greenhouse gas emissions from energy and processing are from making products and chemicals. These emissions can be lowered if they are deliberately considered during the design of products. How can lean product and process development (LPPD) be used to build environmental considerations into the product development system? We explore if LPPD is an effective system in delivering sustainable manufacturing. We conducted case studies in the automotive and oil & gas industries in which LPPD was used to deliver significant physical changes to the product and product manufacturing. We completed semi-structured interviews with stakeholders and focused on the motivation for the change, how LPPD was either a help or hindrance, and the delivered cost savings and environmental benefits. Findings from the case studies were used to structure a workshop on LPPD and sustainability held at a leading manufacturing (industry focused) conference. In this workshop, we focused on first identifying the main environmental impacts in each industry, the physical opportunities to reduce those impacts, and how LPPD might help or hinder delivering that change. This article structures the findings from the case studies and workshop. We present a guide (with examples) for how various LPPD methods (e.g., concept papers, value stream mapping, and design guides) might be used to meet sustainability challenges (e.g., reducing the generation of manufacturing scrap). While LPPD is itself agnostic to sustainability, we suggest that it is an effective method of creating an organizational system for promoting sustainable manufacturing particularly in complex environments.

Incorporating user trust in the development of intelligent systems is one of the new challenges in engineering design field. Trust in human-intelligent system interaction determines how much user relies on the system and directly influences the benefits that an intelligent system provides to human decision-making. This paper reviews the existing literature on trust in human-AI interaction to highlight key areas for engineering system design research to address the overarching issue of user trust in system development. We present how trust influences the use of an intelligent system, describe multiple contexts that users interact with intelligent systems and categorize ways in which trust is formed based on the literature. We classify the key factors that are critical in the formation of user trust in three categories of human user attributes, design of the intelligent system, and task characteristics. We also present the analytical models that exist in the literature used to evaluate and predict trust. This paper is not intended to be a thorough literature review but rather a position paper that provides a structure to the existing literature as a reference for engineering design research. We propose future directions for engineering system design community based on the gaps and open questions identified in the literature.

The Theory of Inventive Problem Solving (TRIZ) method and toolkit provides a well-structured approach to support engineering design with pre-defined steps: interpret and define the problem, search for standard engineering parameters, search for inventive principles to adapt, and generate final solutions. The research presented in this paper explores the neuro-cognitive differences of each of these steps. We measured the neuro-cognitive activation in the prefrontal cortex (PFC) of 30 engineering students. Neuro-cognitive activation was recorded while students completed an engineering design task. The results show a varying activation pattern. When interpreting and defining the problem, higher activation is found in the left PFC, generally associated with goal directed planning and making analytical. Neuro-cognitive activation shifts to the right PFC during the search process, a region usually involved in exploring the problem space. During solution generation more activation occurs in the medial PFC, a region generally related to making associations. The findings offer new insights and evidence explaining the dynamic neuro-cognitive activations when using TRIZ in engineering design.

Smart farming experiential learning and research endeavors have been ongoing at the University of Maryland Eastern Shore (UMES) for the past several years. Recent field implementation of contemporary technologies for variable rate fertilizer application based on multispectral drone imagery; deployment of wireless solar powered soil moisture sensor network on a field with subsurface drip and fertigation capability; and development of a sustainable platform integrated with a Cartesian robotic device powered by solar and wind energy that can seed, weed, irrigate, and capture time-lapse photography while servicing a small raised bed for specialty crops and vegetables will be described in this paper. Results from the initial phase of implementation efforts and future goals will also be highlighted.

Most innovations happen at the intersections of disciplines. New products get designed through synergistic integration of multi-disciplinary concepts. For example, in today’s automobiles purely mechanical systems have been replaced by “by-wire” devices that are software controlled, lighter, more efficient, and reliable. While engineering disciplines are merging seamlessly in real world products, academic silos are mostly still intact. At University of Detroit Mercy, we have broken down some silos by launching the Robotics and Mechatronics Systems Engineering major. Mechatronic Systems Modeling is a mandatory course in this major. This course uses a technique of power flow called bond graphs to model mechatronic systems. This technique is not discipline specific and students with different disciplinary background can easily understand and master it. Recently, the use of Simscape, a MATLAB/Simulink tool for physical system modeling has also been added to this course. The use of these two tools in complex system modeling tasks helps students develop an understanding of engineering system behavior by moving beyond the narrow boundaries of individual disciplines. This paper describes the course content and structure, the modeling methods, selected student projects, some of the lessons learned, and several offshoot activities that have resulted from this course.

Mechatronics and control education is supported by laboratory intensive assignments that allow students acquire software and hardware skills to solve real world problems. However, COVID-19 force many schools to switch into remote learning complicating the instruction of practical assignments. This paper presents a novel proposal for interactive remote teaching of the laboratory component of the course ME-142: Mechatronics at the University of California, Merced using Digital Twins (DT) and the flipped classroom methodology. Each lab experience is composed by a set of on-demand supporting materials with the foundations of mechatronics simulation using MATLAB/Simulink to enhance and adapt the learning experience of the students. Once the students acquire advanced simulation skills, a set of Digital Twin models are provided to the students in order to begin their interaction with virtual representations of real systems for identification, analysis, controller design and validation, which are available online for remote access. By the end of the course, students were able not only to gain valuable experience with mechatronic systems but also interact and build advanced modelling techniques as Digital Twin, contributing to compensate the lack of remote hardware interaction.

The exploration of new lands has always been a source of motivation for mankind. Despite the common idea that our planet is fully known, a huge number of inaccessible places still remains unvisited today, especially below the surface. Recent advances in robotics allow some of these locations to be explored by unmanned vehicles. This paper presents the design of a 3-modules lighter-than-air vehicle specifically conceived to autonomously explore inaccessible caves and underground environments. The design is inspired from an arthropod, scutigera coleoptrata, a long-legged centipede commonly found in our houses. Instead of crawling on walls like its biological counterpart, the robotic scutigera hovers and flies in cave tunnels. The aim is to develop a flexible semi-rigid, segmented airship that can withstand long, smooth explorations of caves while transmitting in real-time the images and sounds that it captures. To develop the model of the system, the kinematics of the modules are obtained in the inertial frame, and the dynamic derivation of the vehicle is obtained using Kane’s equations, which can also be extended for an n-bodies system. Its motion is illustrated with a couple of simplified scenarios in the horizontal plane and only having actuation in the front, or first module, of the airship. A structural design of the modules is presented and supported with a proof-of-concept prototype.

In order to characterize wastewater pumps regarding their clogging behaviour, a wide variety of test procedures with artificial wastewater exist. These tests provide a good insight into the clogging characteristics of a pump. However, conclusions about the clogging mechanisms and their sources cannot be drawn. This paper deals with the design and implementation of an optical access on the suction side of a wastewater pump to allow visualisation of the interaction between impeller and textile via high-speed recordings. The optical access is realized by an endoscope and a connected high-speed camera with a frame rate of 2000 fps and a resolution of 1024 × 1024 pixels. To ensure sufficient illumination of the impeller, a light ring assembled from 12 high power LEDs with a luminous flux of 5595 lumen are circumferentially arranged around the suction side of the pump. The light ring concept is scalable to fit any pump size. A clogging-affine impeller is developed, 3D printed and used for experimental investigations. For the investigated impeller, the blade’s upper area is identified to be crucial for pump clogging. Optical accessibility provides an important contribution to develop non-clogging impellers.

Simulations were used in lecture-based courses, Thermodynamics I and Thermodynamics II, for demonstration purposes and as digital assignments. Digital assignments were separate from the customary pencil & paper homework given once a week. The primary objective was to model the flow and heat transfer in a system, reinforce theoretical concepts, and allow study of more complex two- and three-dimensional problems. Students encounter fluid flow and heat transfer in the sophomore course, Thermodynamics I, for the first time. Velocity, pressure and temperature fields are quite complicated even for simple geometries, hard to visualize, and difficult to understand. Digital assignments go beyond basic theoretical concepts and relatively simple pencil & paper problems. Initially, there were 6 digital assignments in each course. After the first offerings and assessments, the number of assignments is expected to grow to 8–10. Scaffolding of digital assignments ensured that simulations gain in complexity as students become more familiar with both the theoretical underpinnings and the software interface. Our Mechanical Engineering program, has a freshmen graphic communication course incorporating AutoCAD and a junior CAD course with SolidWorks and Ansys. This provided both a challenge and an opportunity for lecture-based thermo-fluids courses positioned ‘in between.’ Modern computational skills were obtained outside the classroom, and that was accomplished with effective use of an on-line environment. Ansys Fluent was chosen to present and reinforce thermo-fluids fundamentals. Each digital assignment had a mesh, detailed grading criteria, and supplementary documentation. Students worked on the: (1) problem set up in the preprocessor-stage, (2) solver, and (3) postprocessor. This approach helped students (1) understand the flow and heat transfer inside the system as well as the application of conservation of mass and energy, (2) understand and interpret results by comparing them with theoretical and experimental data, (3) develop modern technical skills relevant to the demands of Industry 4.0, and (4) develop research capabilities. Simulations in the classroom and as digital assignments are a representation of the real world, and provide an egalitarian and unrestricted way for students to interact with it, acquiring skills and an appreciation for subject matter as well as the engineering profession. Semester long discussions on various aspects of digital assignments help develop a mentor-mentee bond. This approach to teaching, research and mentoring does not depend on access to laboratory facilities and funding that can reach only a limited number of students. It encourages students’ spirit of inquiry, and ultimately leads to a professional development opportunities beyond the classroom setting.

Turbine Control System (DEH) and Turbine Protection System (ETS) are important auxiliary systems for turbines. Normally DEH and ETS are supplied by turbine manufacturers. This paper investigates the operation experience in Nuclear Power Plants (NPPs) in China, there are many problems including information security, maintenance inconvenience, long supply cycle guarantee, high cost and so on in DEH and ETS. This paper analyzes the problems and tries to get the reasons why DEH&ETS have these problems. The Distribute Control System (DCS) technology has been widely used in nuclear power plant in now days, so this paper puts forward a technical solution based on the safety DCS and non-safety DCS platform to realize the DEH and ETS, and according to the feasibility analysis of products, and the test results based on engineering prototype, the solution can solve the problems of DEH and ETS effectively, some performances of the DEH&ETS have been improved, and the solution has a good prospect in further.

With the increasing demands of versatile and long-lasting requirements of deep space missions, space nuclear reactor (SNR) power system is becoming the most potential energy source compared to conventional solar-battery and chemical energy in the future large-scale and long-life space missions. Since the very first successful launch of SNR system (SNAP-10A) in 1965, the United States, the Soviet Union / Russia, the European Union, Japan, Brazil and China have proposed various technical routes and schemes for SNR technologies over the past few decades. This paper presents a historical review of several key technologies (i.e., space nuclear reactor system and thermoelectric conversion system), especially focus on technical progress for recent decade and discusses on-going development activities. The paper also presents a forecast of potential future space applications of these key technologies.

As one of the key technologies of the fourth industrial revolution, Additive Manufacturing (AM, also called 3D printing), which is the basis of innovation design with its high degree of manufacturing freedom, has been widely used in the construction field, aerospace field, automobile manufacturing field, biomedical field, etc. With the increasing maturity of additive manufacturing technology, it has been gradually used in the field of nuclear energy in order to realize design reform. Public reports have shows that additive manufacturing for the pressure vessel fuel, some kinds of fuel pellets, parts of fuel assembly and related core components has been realized. In this paper, the advantages and challenges of additive manufacturing technology used in nuclear fuel assembly design and manufacturing are analyzed, the application status of additive manufacturing technology in the field of nuclear fuel assembly design and manufacturing is summarized, and the application development trend of the additive manufacturing technology for the fuel assembly is also clarified. In general, although the application of the additive manufacturing technology in the field of nuclear fuel assembly design and engineering is still at the stage of research, the application scope of this innovative technology will be greatly expanded with the continuous progress and improvement of the additive manufacturing technology in the near future.

In terms of quality management of raw materials for nuclear power equipment, equipment manufacturers implement quality management for raw materials according to different standards, to ensure the quality and reliability of nuclear power equipment. However, through some typical cases, it is found that many manufacturers do not effectively operate the quality assurance system in the equipment raw material quality management, and there are not enough anti-counterfeiting measures, resulting in unqualified raw material quality affecting the quality of nuclear power equipment. For example, when a manufacturer purchased ASME code grade bars for manufacturing nuclear valves, the raw material supplier forged part of the test reports from the third-party laboratory to make the results meet the requirements of the standard. However, the manufacturer did not find the problem in the procurement process. By comparing the quality assurance requirements of nuclear power units under different standards, this paper analyzes the problems in the process of raw material purchasing and quality management, combined with some measures and requirements to prevention CFSI, puts forward some suggestions for optimizing the quality assurance of raw materials for nuclear power equipment.

The accelerator-driven subcritical system (ADS) can transmute nuclear waste by using high-energy neutrons, which is the most effective nuclear waste disposal scheme at present. The zero-power lead-bismuth alloy device accurately constructed the interaction mode between nuclear fuel and lead-bismuth alloy coolant material, and more accurately simulated the core physical characteristics of lead-bismuth reactor. Moreover, the inherent safety of the reactor is enhanced by installing several passive safety shutdown systems. However, due to the particularity of the potential harm caused by radioactive material leakage, nuclear-grade equipment should maintain high safety performance under many working conditions, such as earthquake working conditions. To ensure the safe operation of the ADS zero-power device and the safe shutdown under seismic conditions, the motion of the control rod of the ADS zero-power device must be analyzed under seismic conditions. At present, most studies on the control rod drop analysis focus on water reactor, but this paper will analyze and calculate the control rod drop of the lead reactor. In this paper, the physical mechanism of rod falling of the control rod component is analyzed, and the influence of contact collision between the control rod component and the guide tube of the control rod on the whole rod falling time is considered. In this paper, the finite element method is used for transient analysis of ADS lead-bismuth alloy zero power reactor, and the time history diagram of the control bar position is obtained under the seismic conditions, thus verifying that ADS lead-bismuth alloy zero power reactor can be safely shut down under the safe shutdown earthquake (SSE).

The decommissioning technology of nuclear facilities has been one of the most important research directions of nuclear industry for several decades, and further enhancements are being carried out in the world. The global published patents about the decommissioning technology of nuclear facilities are investigated in this work. The technology forecasting and the development strategy of the decommissioning technology of nuclear facilities was provided from the view of patents, based on the nations, the technology field, the trend in the number of patents applications. This work will contribute to understanding the advanced developments of the decommissioning technology of nuclear facilities by a new perspective. Through quantitative statistics and content analysis, the understanding of relevant industries and technology development trend of personnel in the industry is promoted from the perspective of open patent data, a complex of technology, law and economy. Through the technology and economy behind the patent data to ensure its reliability and authenticity, this paper puts forward suggestions and prospects for the practitioners in the field of nuclear facilities decommissioning from the aspects of how to combine the research and analysis of patent situation with the development of the industry.

Decommissioning of the Fukushima Daiichi nuclear power station (NPS) is an unprecedented effort in which the entire plant was contaminated with radioactive materials from the accident and radiation dose levels were not low. The decommissioning workers in these sites are indicated to wear personal protective equipment (PPE) properly for radiation protection. In response to the difficulties of on-site PPE management in decommissioning site of Fukushima Daiichi NPS, this paper presents a graph-based scene understanding approach that automatically identifies whether workers at a decommissioning site are using PPE properly. The experimental results demonstrate that the high precision and high recall of the model can effectively detect decommissioning workers’ failure use of PPE and can facilitate improved safety inspection and supervision.

Nuclear technology, as a high quality, clean and reliable energy supply, is attracting broad interest from countries across the world. F321 austenitic stainless steel (F321SS) is widely utilized in key components of nuclear power plant due to its excellent corrosion resistance and high temperature mechanical properties. Irradiation can easily lead to the degradation behaviors of materials, such as irradiation hardening, irradiation embrittlement and high-temperature He embrittlement, etc. Understanding such degradation is important for predicting the evolution of material behavior under irradiation and extending the lifespan of existing nuclear reactors. Ion irradiation is most commonly used to model neutron-induced damage since the irradiation conditions (temperature, flux, spectrum, etc.) can be regulated more accurately and flexibly. In this paper, the Fe-ion irradiation experiments of F321SS at different temperatures and doses were carried out, and the nanoindentation experiments under different conditions were further conducted. Irradiation hardening is observed in all specimens and strongly depending on irradiation temperature and damage dose. The hardness after irradiating increases with doses and saturates for at least 1dpa under low temperature regimes (< 300°C). However, at higher temperature (450°C and 560°C), nano-hardness reaches the peak at ∼0.5dpa and then declines. Moreover, the hardness of all specimens has a similar trend with temperature, that is, it first increases, reaches the peak, and then decreases.

Pressure-temperature ratings for aluminum alloy flanges made from ASTM B247 3003-H112 and 6061-T6 materials are covered in ASME B31.3 Appendix L since 1995. They were previously included in ANSI B16.5 between 1960 and 1968, and in ANSI B16.31 Non-ferrous Alloy Flanges from 1968 and until it was withdrawn in 1981. In 2018, Xu and Rana [PVP 2018-84076] used a modified version of the rules for establishing the pressure-temperature rating from ASME B16.5 Steel Flanges to re-assess the pressure-temperature rating of aluminum alloy currently listed in ASME B31.3 Appendix L. Based on their work, they recommended raising the pressure-temperature ratings for Classes 150, 300 and 600, as well as expanding rating to cover Classes 900 and 1500. In this paper, the author will revisit this topic, explain the background of why ANSI B16.31 was withdrawn and the drawbacks of higher pressure-temperature rating of aluminum alloy flanges. The author will also explain the concept of “ceiling pressure” used in B16 standards to cap the maximum pressure rating for flanges and valves, and significant difference in the modulus of elasticity between Carbon Steel and Aluminum alloys, and its impact on flange rigidity and leak tightness, and will propose alternative rules for establishing the pressure-temperature ratings for aluminum alloy flanges.

The ASME Code, Section III, provides rules for the evaluation of cyclic loading that include evaluations of fatigue. These rules were first developed in the 1960s along with the original development of Section III. Since then, technology and analytical advancements have improved our understanding of the fatigue phenomenon. As an example, the developments in environmentally assisted fatigue (EAF) have become a major consideration in the low-cycle fatigue for light water reactors and plant life extension. Fatigue usage has an outsized impact on the overall cost and complexity of nuclear plants, which goes beyond just the qualification of ASME components. For example, pipe break locations, pipe whip restraints, and inservice inspections are, in part, based on fatigue analysis results. Therefore, it is important that fatigue analyses provide the most realistic assessment of fatigue with appropriate conservatism. The Section III Standards Committee has been working to keep the Code up to date with the latest research, analysis tools and fatigue data. In 2017, a Fatigue Steering Committee was formed to provide a venue for stakeholders to identify and coordinate development of updated fatigue design criteria, analysis methods, and their associated physical and thermo-mechanical properties for application to Section III of the ASME BPV Code. The stakeholders include many international organizations including the Japan Society of Mechanical Engineers. Many PVP papers have been used as the basis for the Fatigue Action Plan items. The Steering Committee completed its work in 2019 with the adoption of a Fatigue Action Plan, which provided a vision for advanced fatigue approaches. The Fatigue Action Plan recommended specific Code actions and activities to guide and coordinate the Code actions in the area of fatigue. This paper outlines the overall Fatigue Action Plan and provides an update on the implementation progress. Section III has already accomplished several actions on the Fatigue Action Plan by publishing numerous Code Cases and Code revisions that have improved the analysis tools available to designers to address fatigue. This paper provides an overview and introduction to these Code Cases and other tools for designers. The Fatigue Action Plan was largely based on addressing the need for the light water reactor fleet to address low cycle thermal fatigue. The Committee also recognizes that going forward the Fatigue Action Plan must address the needs of the growing advanced reactor community as well as other users of the Code. The paper discusses these needs and Section III plans to meet these future needs.

The rules for the design of high temperature reactor components in Section III, Division 5, Subsection HB, Subpart B (HBB) of the ASME Boiler and Pressure Vessel Code contain two options for evaluating the deformation-controlled design limits on strain accumulation and creep-fatigue: design by elastic analysis and design by inelastic analysis. Of these options design by inelastic analysis tends to be less overconservative and produce more efficient designs. However, the HBB currently does not provide approved material models for use with the inelastic analysis rules, limiting their widespread use. A nonmandatory appendix has been developed to provide general guidance on appropriate material models and provide reference material models suitable for use with the design by inelastic analysis approach. This paper describes a viscoplastic model for Alloy 617 suitable for use with the HBB rules proposed for incorporation into the new appendix. The model represents the high temperature creep, creep-fatigue, and tensile response of Alloy 617 and accurately accounts for rate sensitivity across a wide range of temperatures. The focus in developing the model was on capturing key features of material deformation required for accurately executing the HBB rules and on developing a relatively simple model form that can be implemented in commercial finite element analysis software. The paper validates the model against an extensive experimental database collected as part of the Alloy 617 Code qualification effort as well as against specialized experimental tests examining the effect of elastic follow up on stress relaxation and creep deformation in the material.

The seismic probabilistic risk assessment is an important methodology to evaluate the seismic safety of nuclear power plants. In this assessment, the core damage frequency is evaluated from the seismic hazard, seismic fragilities, and accident sequence. Regarding the seismic fragility evaluation, the probabilistic fracture mechanics can be applied as a useful evaluation technique for aged piping systems with crack or wall thinning due to the age-related degradation mechanisms. In this study, to advance seismic probabilistic risk assessment methodology of nuclear power plants that have been in operation for a long time, a guideline on the seismic fragility evaluation of the typical aged piping systems of nuclear power plants has been developed considering the age-related degradation mechanisms. This paper provides an outline of the guideline and several examples of seismic fragility evaluation based on the guideline and utilizing the probabilistic fracture mechanics analysis code.

In the past couple of decades there have been significant developments in the fatigue design approach for metallic bellows expansion joints. For example, where there were previously separate fatigue curves for reinforced and unreinforced bellows, there is now only one fatigue curve. This paper describes the developments over time and explains the technical reasons for the changes.

Implementing the generation IV nuclear reactor concept to nuclear service needed elevated temperature component analysis and design methodologies. These components experience elevated temperature loads such as creep, fatigue, creep-fatigue, and ratcheting. Traditional elastic, simplified inelastic, or elastic-perfectly plastic analysis and design methods per Section III, Division 5 fails to capture the detailed material behavior. Full inelastic analysis methods governed by the unified constitutive model (UCM) have shown promise in capturing the complicated material behavior at elevated temperatures. Current Section III, Division 5 design code do not provide guidelines for UCM based full inelastic analysis of Gen. IV components using finite element methods. Gap analysis of the current Section III, Division 5 design code indicated the need to develop unified constitutive models (UCMs) and their optimized parameter sets for performing full inelastic analysis. This paper presents a UCM with two and four nonlinear kinematic hardening rules for diffusion bonded (DB) Alloy 800H. Experiments on DB Alloy 800H are performed for developing and validating a UCM. The developed UCM captures the critical fatigue, creep, and creep-fatigue response features such as hysteresis loop, stress relaxation, rate effects, and cyclic hardening demonstrated by DB Alloy 800H experiments performed. Description of the UCM model developed and its optimized parameters for DB Alloy 800H and cor-responding simulations are presented. Future works to further develop the UCM are discussed.

This paper provides an overview of the significant revisions to the upcoming 2021 edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) Section VIII Division 3, Alternative Rules for Construction of High Pressure Vessels, as well as potential changes to future editions under consideration by the Subgroup on High Pressure Vessels (SG-HPV).

Degradation found in carbon steel Service Water piping is typically characterized as localized corrosion or “pitting.” Localized corrosion or pitting is identified as small sections of thinning that deviate from the average wall thickness. In its most basic sense, a pit is simply a geometric entity that is abrupt and distinct that can range in size, extent, and density throughout the system. This raises the question of how one defines a pit and what geometric characteristics can be used to create this definition. Research has been conducted to help provide answers to this question through detailed study of wall thickness examination results on operating service water piping in a nuclear power plant. This analysis has determined that the primary geometric characteristics are the depth-to-extent ratio, the extents of thinning, the shape of the pit, and the distance between adjacent pits. Statistical distributions of these characteristics for the evaluated data sets were developed to understand the overall trends of the pitting. With further research, the results of this evaluation can be used to extrapolate these trends of pitting characteristics, with high statistical confidence, to sections of service water piping that have little to no detailed non-destructive examination data. The objective of this paper is to present the preliminary findings of the statistical study on “pitting” and provide a set of geometric characteristics that best define a pit.