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Porous metal bearings are widely used in small and micro devices. To compute the pressure one has to solve the Reynolds equation coupled with the Laplace equation. We show that it is possible to give to the relevant boundary value problem a variational formulation. We show that the pressure of the film in a porous bearing is less than that of the corresponding non-porous bearing.

AIMS Sacral neuromodulation (SNM) has successfully treated patients with functional urinary and/or bowel disorders for more than two decades. Historically, patients with the InterStim system (Medtronic) were contraindicated for Magnetic Resonance Imaging (MRI) scans. In 2012, Medtronic obtained Food and Drug Administration (FDA) approval for allowing 1.5 Tesla (T) MRI head scans. In September 2019, the Axonics System (Axonics) received FDA approval for 1.5 T full-body MR Conditional labeling and then 3 T full-body MR Conditional labeling in July 2020. In August 2020, Medtronic received 1.5 and 3 T full-body MR Conditional labeling from the FDA for their new SNM systems (InterStim II and Micro devices with SureScanTM leads). With the advancements in MRI technology and availability of full-body MRI eligible SNM systems, it is important for physicians to better understand MRI safety for these systems. METHODS This paper explains the fundamentals of MRI physics, its interactions with active implantable medical devices (AIMDs), the subsequent potential safety hazards with emphasis on radio frequency (RF)-related safety, and the risks associated with "Off-label" scans, including abandoned and broken leads. RESULTS MRI guidelines provided by the AIMD device manufacturer should be followed to ensure MRI scan safety and avoid any unnecessary risk to patients. CONCLUSIONS MRI guidelines provided by the device manufacturer are the best resource for guidance for performing safe MRI scanning. Specific conditions should be fully understood and generalizations on MRI safety claims based on partial analysis or case studies should be avoided.

Nowadays, organizations need to have innovation mechanisms, and this is due to the market constantly evolving. This ever-changing climate may cause instability within organizations, in some cases even lead them to a scenario of bankruptcy. In this case study, we analysed the unlikely success story of Advanced Micro Devices (AMD). AMD is a company that operates in the semiconductor industry. A company responsible for computer processors since 1969, and more recently it went through a major change in its strategic management to survive a bankruptcy situation. Even though AMD showed a lack of adaptation throughout the years, especially when smartphones and tablets first appeared, AMD has, since then, turned their focus towards what they are fundamentally good at, and they bet on those segments, which were high performance computer components. These segments were mostly dominated by very few players, such as Intel and Nvidia. This restructuration was led by Dr. Lisa Su, as she rethought the various strategies used by the company, propelling AMD once again to the top and making it one of the market leaders in the technology industry. In this study we focused on the successful case of AMD, by understanding the type of strategy chosen by the company and how it influenced its ongoing success. To achieve this, we collected information in various ways. Regarding the gathering of information about the company, an analysis of Dr Lisa Su’s interviews and the organization’s website was made. After carrying out these tasks, academic articles were read to identify the approaches selected by the company. Dr. Lisa Su’s management proved to be fundamental to the company’s success, as her futuristic vision and her ability to bet on promising products allowed AMD not only to face its biggest competition, but also to go head-to-head against it. This study suffered some limitations in terms of data collecting since there was no opportunity to talk with the company and consequently ended up being based on the formed opinion of the authors.

With the advancement of micro-electro-mechanical systems (MEMS) technologies, it is compulsory to have the sources which power the micro devices at micron scale. Due to the miniaturization, compactness, inexpensive and ease of integration with the standard process compatibility, CMOS-MEMS capacitor is characterized. There are two major parts of characterization; static mode and dynamic mode. The moveable shuttle remains in static mode until the input voltage reaches to 50 V. In static mode, due to constant capacitance among stator and shuttle fingers, charge accumulates up to 1.17 pC and level of energy stored does not go so high. The shuttle fingers initially overlap with the stator fingers by 30 μm but in dynamic mode when the voltage raises above 50 V, moveable shuttle starts moving and fingers overlapping distance reaches to 50 μm with the increase in voltage of approximately 307 V. In dynamic mode, stored energy level increases from 30 to 1800 pJ. The stored energy increases exponentially in dynamic mode due to the increased overlapping of the fingers and against elastic forces of beams (1, 2, 3 and 4).

The emergence of Cyber-Physical Systems (CPS) based principles and technologies holds the potential to facilitate global collaboration in various fields of engineering. Micro Devices Assembly (MDA)...

In the past decades, wireless milli and micro devices have been incorporated into medical procedures as a way to reduce invasiveness. However, the commercially available methods still consist of passive locomotion devices, which is a limiting factor to the development of minimally invasive devices. Magnetism simplifies the design of small-scale devices since it does not require on-board batteries or motors. This review presents locomotion techniques and features using magnetic actuation towards minimally invasive procedures. Requirements, advantages, and challenges are discussed.

“Microfluidics” is a generalized term denoting both, the science studying the conduct of fluids (gases and liquids) through microchannels and the manufacturing technology of micro miniature devices containing chambers and tunnels through which fluids flow or are confined to flow. Advancement in the field of nanotechnology has emphasized on the use of microfluidics due to several benefits associated with this technology in comparison to conventional techniques of nanoparticle fabrication. Microfluidic reactors have offered a vast range of advantages including better controllability and uniformity of nanoparticle characteristics. Potential applications of nanoparticles have made them an undeniable tool in the field of pharmaceuticals. Though nanoparticles are foreseen to overcome the challenges in effective delivery of therapeutic agents, the drawbacks associated with traditional preparation techniques has resulted in slow translation from research to clinical applications. Production of nanoparticles in commercial scale is an existing active challenge which could be overcome by the exciting opportunities of microfluidic technology to develop easy, safe and cost-effective drug delivery systems with good reproducibility. This chapter encompasses an overview of microfluidics technology in the production of nanoparticles and the use of micro devices as tools for investigation.

Energy losses originating from friction and wear are estimated to be 23% of the world’s total primary energy consumption. Reduction of friction is not only a problem to be solved in engineering application, but also a technical barrier for micro devices such as microelectromechanical systems. New lubrication techniques and materials related to energy-saving and green industry are urgently needed. Today, some advanced solutions have been proposed to potentially solve friction and wear problems for micro- or nanoelectromechanical system. Technologies of ultralow friction coefficient even superlubricity can greatly improve the energy efficiency of relative motion system. Up to now, a large number of superlubricity phenomena have been found, and several important superlubricity mechanisms have been revealed. In this chapter, we introduce a new phenomenon discovered recently to realize superlubricity, that is, the vibration-induced superlubricity, and its mechanism has been discussed.

This paper presents a new approach towards the design of paper based autonomous microfluidic devices. Autonomy in the device operation is achieved through the incorporation of mechanically actuated microfluidic switches that are versatile in their design and may be configured to be simple time triggered ON or OFF switches or more complex switches that can be timed to be in multiple states (timed ON, followed by timed OFF). These switches are self-contained and require no external power for their operation, deriving their functionality solely through stored elastic energy. This paper presents the design and fabrication of these switches as fluidic analogs of electronic transistors, and their integration into microfluidic paper based circuit demonstrating their operation as a programmable paper-based microfluidic device.

Advancement in the miniaturization of high-density power sources, electronic circuits, and communication technologies enabled the construction of miniaturized electronic devices, implanted directly in the heart. These include pacing devices to prevent low heart rates or terminate heart rhythm abnormalities (‘arrhythmias’), long-term rhythm monitoring devices for arrhythmia detection in unexplained syncope cases, and heart failure (HF) hemodynamic monitoring devices, enabling the real-time monitoring of cardiac pressures to detect and alert for early fluid overload. These devices were shown to prevent HF hospitalizations and improve HF patients’ life quality. Pacing devices include permanent pacemakers (PPM) that maintain normal heart rates, defibrillators that are capable of fast detection and the termination of life-threatening arrhythmias, and cardiac re-synchronization devices that improve cardiac function and the survival of HF patients. Traditionally, these devices are implanted via the venous system (‘endovascular’) using conductors (‘endovascular leads/electrodes’) that connect the subcutaneous device battery to the appropriate cardiac chamber. These leads are a potential source of multiple problems, including lead-failure and systemic infection resulting from the lifelong exposure of these leads to bacteria within the venous system. One of the important cardiac innovations in the last decade was the development of a leadless PPM functioning without venous leads, thus circumventing most endovascular PPM-related problems. Leadless PPM’s consist of a single device, including a miniaturized power source, electronic chips, and fixating mechanism, directly implanted into the cardiac muscle. Only rare device-related problems and almost no systemic infections occur with these devices. Current leadless PPM’s sense and pace only the ventricle. However, a novel leadless device that is capable of sensing both atrium and ventricle was recently FDA approved and miniaturized devices that are designed to synchronize right and left ventricles, using novel intra-body inner-device communication technologies, are under final experiments. This review will cover these novel implantable miniaturized cardiac devices and the basic algorithms and technologies that underlie their development. Advancement in the miniaturization of high-density power sources, electronic circuits, and communication technologies enabled the construction of miniaturized electronic devices, implanted directly in the heart. These include pacing devices to prevent low heart rates or terminate heart rhythm abnormalities (‘arrhythmias’), long-term rhythm monitoring devices for arrhythmia detection in unexplained syncope cases, and heart failure (HF) hemodynamic monitoring devices, enabling the real-time monitoring of cardiac pressures to detect and alert early fluid overload. These devices were shown to prevent HF hospitalizations and improve HF patients’ life quality. Pacing devices include permanent pacemakers (PPM) that maintain normal heart rates, defibrillators that are capable of fast detection and termination of life-threatening arrhythmias, and cardiac re-synchronization devices that improve cardiac function and survival of HF patients. Traditionally, these devices are implanted via the venous system (‘endovascular’) using conductors (‘endovascular leads/electrodes’) that connect the subcutaneous device battery to the appropriate cardiac chamber. These leads are a potential source of multiple problems, including lead-failure and systemic infection that result from the lifelong exposure of these leads to bacteria within the venous system. The development of a leadless PPM functioning without venous leads was one of the important cardiac innovations in the last decade, thus circumventing most endovascular PPM-related problems. Leadless PPM’s consist of a single device, including a miniaturized power source, electronic chips, and fixating mechanism, implanted directly into the cardiac muscle. Only rare device-related problems and almost no systemic infections occur with these devices. Current leadless PPM’s sense and pace only the ventricle. However, a novel leadless device that is capable of sensing both atrium and ventricle was recently FDA approved and miniaturized devices designed to synchronize right and left ventricles, using novel intra-body inner-device communication technologies, are under final experiments. This review will cover these novel implantable miniaturized cardiac devices and the basic algorithms and technologies that underlie their development.

In this work, we address the modelling of piezo-micromirrors with large opening angles. We focus on various sources of nonlinearites induced by the interaction with the surrounding fluid and by occurrence of geometric large transformations. Specific attention is also devoted to the piezoelectric coupling coefficient. Piezoelectric thin films have gained attention as key materials for the actuation of micro devices since they provide high drive forces, enabling devices with higher performances compared to electrostatic actuation. However they also induce material nonlinearities that cannot be neglected. The model is validated using experimental data obtained for various excitation levels. [2020-0229]

We report a facile patterning technique for precise controlling the degradation of silk protein based optical micro devices by rapid thermal nanoimprinting for transient applications. The solubility of silk films strongly depends on the crystalline conformation of the silk proteins, which can be well tuned by the spatial and temporal modification during thermal treatment. Compared with the previous methods, this approach mainly focuses on the customizing the degradation order and rate of multiple-drug-loaded soluble silk optics for programmable drug release and real-time monitoring via optical read-out. It opens up opportunities for manufacturing high-performance transient devices with programmable degradation rates.

Background: This review describes the use of molecularly imprinted polymers (MIPs) as tailor-made adsorbents for developing micro-solid phase extraction (µ-SPE) procedures when isolat-ing/assessing organic pollutants, drugs, and bioactive compounds from environmental, food, and clini-cal/forensic samples. Objective: Developments in MIP-µ-SPE are focused on synthesizing selective MIPs before preparing micro devices, and also when synthesizing MIPs onto nanoparticles such as magnetite (magnetic MIPs). Conclusion: The current paper also reviews advances in MIPs synthesis onto quantum dots (MIP-QDs) for fluorescenssce sensing of organic compounds, advantages and drawbacks of each methodology, and future expected trends.

The paper presents the new methods of use of processing technologies for realizing proof-of-concept new medical micro-devices components. By using both classical mechanical machining and unconventional laser beam cutting and welding combined with soldering two proof-of-concept medical devices components were realized. The materials processed were stainless steel and super-elastic nitinol alloy. The selection of the processing technologies was done based on the specific requirements of the devices components as well as the characteristics of the applied materials. The selected technologies were fit for the requirements of the proof-of-concept medical micro-devices components, further RTD work being needed in order to comply with the bio-compatibility and in-exploitation requirements. The specific outcomes of using classical mechanical machining and laser beam processing are presented.

The non-uniformity of electroformed layers directly affects the mechanical properties and application requirements of micro devices. Therefore, uniformity of electroformed copper foil is significan...

Micro Devices Assembly (MDA) is an emerging domain involving the assembly of micron sized objects and devices. In this paper, the focus is the design of an IoT based Cyber Physical approach for the assembly of micro devices. An advanced IoT based framework comprising of integrated cyber and physical components has been developed to accomplish a targeted set of MDA life cycle activities which include assembly planning, Virtual Reality (VR) based assembly analysis, command generation and physical assembly. Advanced VR based environments using semi-immersive and fully immersive technologies (including Oculus Rift based platforms) have been designed to support assembly analysis where plans can be proposed, compared and validated. An information centric modeling approach is proposed to help design the data/information exchange among the various cyber and physical components and provide a structured foundation to design such complex IoT based approaches and frameworks.

Owing to the massive growth in the field of biomedical microsystems, a variety of innovative micro-electro-mechanical systems (MEMS) devices have been introduced. For decades, the health care sector has been using macro devices but due to the various disadvantages that came along with the macro devices, research about micro devices began. Micro devices have various advantages such as low energy consumption, lightweight, biocompatibility, small size and many more. This paper mainly focuses on application of MEMS in the field of medicine in three main fields: (1) MEMS in diagnosis (2) MEMS in precision surgery (3) MEMS in therapeutic systems. BioMEMS in diagnosis help in precise and early detection of medical conditions. BioMEMS in the surgical field help in performing less invasive surgery and thus shorter recovery period. BioMEMS in therapeutic field enable therapy treatment with increased efficiency. Micro and miniature devices offer numerous novel treatments that can be performed with more precision and less complication. It is a challenging research field as it involves the study of complex functions of living bodies. Miniaturized analytical, surgical and therapeutic microsystems will become a necessity for the medical field in the long term, to obtain a more delineated view into the processes of the living body and to deliver precise quantity of drugs more efficiently. Application of BioMEMS in the area of stent fabrication, microneedles patch requires more research and has the potential to improve health care.

We propose the smallest preload generation mechanisms that provide force between the rotor and the one cubic millimeter stator in a micro ultrasonic motor. Miniaturizing the preload mechanism is key for implementation of a micro ultrasonic motor with the best performance into micro devices. In this paper, we evaluate two kinds of preloads that exert in the axial and radial directions: an axial preload mechanism and a radial preload mechanism. The experiments clarify how both preload mechanisms improve motor performance measures such as angular velocity, torque, and efficiency. The micro ultrasonic motors with both preload mechanisms generated torque over 10 μNm at the experimentally optimized preload of approximately 6 g. By designing the miniature preload mechanisms using a micro coil spring, the preload mechanisms are miniaturized with similar motor performance. At present, they represent the smallest and most powerful ultrasonic motors with preload mechanisms.

A scheme for magnetic based biomolecular separation, transportation and detection has been proposed, designed, fabricated and successfully demonstrated through a novel micro-fabricated magnetic system. Magnetic separation becomes a popular technique to purify or isolate cells, intracellular and biological active compounds from heterogeneous mixtures. This thesis introduces and demonstrates a fully micro-magnetic system as a magnetic potential concentrator for manipulating micro/nano magnetic particles in bio- molecular separation systems. The functional components of the device are an electrically phased planar electromagnet array and magnetic pillars positioned at specific locations above the surface of the planar electromagnets. The components are located in a microfluidic chamber with a capacity of 5 l. This system presents a new tool of magnetic control for manipulating and sampling biochemical compounds. DOCTOR OF PHILOSOPHY (EEE)

Polymer micro devices or components are becoming more and more popular in bio-MEMS filed, such as micro-fluidic chips. In this paper, ultrasound provided by a commercial ultrasonic welding machine, was introduced to the molding process of micro devices from polymer films. Several layers of polymer films were ultrasonically heated and molded into a micro device. Micro-fluidic chips consisting of two substrates with micro-channels and connectors were demonstrated by ultrasonic molding process. The experiments show that ultrasonic molding based on multilayer of polymer films is a low-cost and high-efficiency method to fabricate micro polymer devices.

The emerging research field of functional micro devices and microbots aims at developing remote-controlled microsensors and actuators that can operate inside living organisms for biomedical applications. However, a significant gap remains in controlling with high accuracy such microdevices in complex environments. This is primarily due to the lack of high spatial and temporal resolution techniques. Here we demonstrate the detection of synthetic microstructures with sizes between 10 and 50 µm size, in deep tissue-mimicking phantoms, using multispectral optoacoustic tomography (MSOT). When referring to guidance/propulsion, cargo-delivery, and imaging capabilities, these microstructures represent key components of the physical, chemical and biohybrid microbots. They are conceived for diverse in vivo medical applications, including non-invasive diagnosis and therapy.

This chapter introduces several investigations including development of novel processes including combining micro press-forming and automatically assembling in a progressive die for fabrication of micro devices, heat-assisted forming, dieless tube forming, and coating system for micro-die adapted to microforming. Micro parts in several hundreds of micrometers and a micro pump in several millimeters were made by using this microforming technology. Several investigations were carried out to indicate the advantages of heating-assisted microforming for improving and formability of workpiece and accuracy of the product. The heat-assisted microforming system with resistance heating was designed to satisfy low energy consumption and high forming accuracy to heat only the workpiece material and to limit the heat transferring to tools. Microtube which is one of the important micro components is used in various applications such as a painless injection needle and stent, heat exchanger, and micro nozzle. The chapter discusses the die surface treatment toward the final goal of the achievement of lubricant-free microforming.

Fabrication of soft actuators that may perform multiple tasks simultaneously, as observed for the complex natural systems, is one of the goals in biomimetics. Biomolecular motor systems are the smallest natural machine that can perform mechanical work with a high efficiency. Because of their wide range of scalability and adaptability, the biomolecular motor systems are promising candidates for developing biomimetic soft actuators. The biological power units are able to convert chemical energy obtained from hydrolysis of adenosine triphosphate (ATP) into mechanical work. By virtue of their highly efficient mechanism of power generation, they are able to form highly ordered structures in living organism, which facilitates their emergent functions. To exploit the advantages of the biomolecular motor systems, nowadays they are used as building blocks of biomimetic soft actuators or devices. In this chapter we discuss the latest applications of a classical biomolecular motor system microtubule/kinesin in designing biomimetic soft actuators and micro devices. Nowadays the microtubule/kinesin system can be reconstructed and self-assembled or integrated to complex hierarchical structures which offer emergent functions. Utilization of biomolecular motor systems can greatly advance the development of highly efficient biomimetic soft actuators which in turn would benefit soft robotics in near future.

Analysis of radionuclides in radioactive waste is performed according to a number of operating protocols which are usually time-consuming and difficult to implement. The use of micro devices for liquid-liquid extraction of radionuclides is promising, since small amounts of materials are needed. In this work, a plug flow modelling approach for the liquid-liquid extraction in microdevices is presented. A multi-component chemical process based on the PUREX-TRUEX waste management treatment is analysed. We evaluate the performance of the coupled micro-units as a function of channel size, superficial mixture velocity, and initial loading. The results show that it is possible to use the model in an optimisation based design procedure for microfluidic devices.

Oral delivery of peptides is challenging due to their low uptake through the small intestinal epithelium. Tight junctions, connecting the enterocytes, impede permeability, often necessitating the use of permeation enhancers in the formulation. Loading of peptide and permeation enhancer into micro-scale devices, such as microcontainers, can potentially confine the effective absorptive area through unidirectional release and thereby enhance absorption. This concept is investigated by in vitro permeation studies of insulin across Caco-2 cell and Caco-2/HT29-MTX-E12 co-culture monolayers mimicking the intestinal absorption barrier. The importance of proximity between the microcontainers and the barrier is assessed, by keeping the amounts of insulin and sodium caprate fixed throughout all experiments, while collectively orienting the unidirectional release towards the cell monolayers. Increasing the distance is observed to have a negative effect on insulin permeation matching a one-phase exponential decay function, while no difference in insulin transport is observed between Caco-2 and co-culture monolayers. Although there are no signs of cytotoxicity caused by the microcontainer material, reversible cell deterioration, as a consequence of high local concentrations of sodium caprate, becomes evident upon qualitative assessment of the cell monolayers. These results both suggest a potential of increasing oral bioavailability of peptides by the use of microcontainers, while simultaneously visualising the ability of regaining monolayer integrity upon local permeation enhancer induced toxicity.

With the advent and breakthrough of interaction between humans and electronic devices using speech in communication, we have seen a lot of applications using speech recognition and speech synthesis technology. There are some limitations we have identified to these applications. Availability of a lot of resources and internet connectivity have made it possible in making case but with limited resources it is quite difficult to achieve this feat. As a result, it limits the application of the technology into micro devices and deploying them into areas where there are no internet connectivity. In this article, we developed a smaller Deep Neural Network models for Automatic Speech Recognition (ASR) and Text-to-Speech (TTS) for communication on micro devices such as Raspberry Pi. We tested and evaluated the models of the system. The accuracy and the performance of the models to be implemented on micro devices shows that they are good for application development in micro devices.

Research on the biotechnology field using micro devices has been carried out variously, and we focus on mechanical stimulation to biological samples in this paper. However, dedicated devices such as microprobes tend to be expensive and are not easy to fabricate. Therefore, we propose a device which can stimulate the biological sample using PDMS structure deformation by pressure control, and can easily fabricate it. By measuring the relationship between inlet pressure and PDMS deformation, we confirmed the stability of behavior of the proposed device. Furthermore, using the proposed device, an experiment system for roots of broccoli sprout is constructed.

Activity monitors such as the SenseWear Pro3 (SWP3) and the activPAL3 Micro (aP3M) are regularly used by researchers and practitioners to provide estimates of the metabolic cost (METs) of activities in free-living settings. The purpose of this study is to examine the accuracy of the MET predictions from the SWP3 and the aP3M compared to the criterion standard MET values from indirect calorimetry. Fifty-six participants (mean age: 39.9 (±11.5), 25M/31F) performed eight activities (four daily living, three ambulatory and one cycling), while simultaneously wearing a SWP3, aP3M and the Cosmed K4B2 (K4B2) mobile metabolic unit. Paired samples T-tests were used to examine differences between device predicted METs and criterion METs. Bland–Altman plots were constructed to examine the mean bias and limits of agreement for predicted METs compared to criterion METs. SWP3 predicted MET values were significantly different from the K4B2 for each activity (p ≤ 0.004), excluding sweeping (p = 0.122). aP3M predicted MET values were significantly different (p < 0.001) from the K4B2 for each activity. When examining the activities collectively, both devices underestimated activity intensity (0.20 METs (SWP3), 0.95 METs (aP3M)). The greatest mean bias for the SWP3 was for cycling (−3.25 METs), with jogging (−5.16 METs) producing the greatest mean bias for the aP3M. All of the activities (excluding SWP3 sweeping) were significantly different from the criterion measure. Although the SWP3 predicted METs are more accurate than their aP3M equivalent, the predicted MET values from both devices are significantly different from the criterion measure for the majority of activities.

Response characteristics in the opening and closing operations of the micro magnetic fluid diaphragm mechanism by the alternating magnetic field are described. The micro magnetic fluid diaphragm mechanism was composed of a ring shaped permanent magnet and kerosene-based magnetic fluid. The driving principle of micro magnetic fluid device was based on the surface phenomena of magnetic fluid adsorbed on a permanent magnet. The opening and shutting time of diaphragm mechanism in the alternating magnetic field was measured by high-speed video camera system. The details of magnetic fluid surface response in the opening and closing operations of magnetic fluid hole were revealed experimentally.