Unlimited Lifetime Research Articles

Multi-Junction Solar Module and Supercapacitor Self-Powering Miniaturized Environmental Wireless Sensor Nodes

A novel prototype based on the combination of a multi-junction, high-efficiency photovoltaic (PV) module and a supercapacitor (SC) able to self-power a wireless sensor node (WSN) for outdoor air quality monitoring has been developed and tested. A PV module with about an 8 cm2 active area made of eight GaAs-based triple-junction solar cells with a nominal 29% efficiency was assembled and characterized under terrestrial clear-sky conditions. Energy is stored in a 4000 F/4.2 V supercapacitor with high energy capacity and a virtually infinite lifetime (104 cycles). The node power consumption was tailored to the typical power consumption of miniaturized, low-consumption NDIR CO2 sensors relying on an LED as the IR source. The charge/discharge cycles of the supercapacitor connected to the triple-junction PV module were measured under illumination with a Sun Simulator device at selected radiation intensities and different node duty cycles. Tests of the miniaturized prototype in different illumination conditions outdoors were carried out. A model was developed from the test outcomes to predict the maximum number of sensor samplings and data transmissions tolerated by the node, thus optimizing the WSN operating conditions to ensure its self-powering for years of outdoor deployment. The results show the self-powering ability of the WSN node over different insolation periods throughout the year, demonstrating its operation for a virtually unlimited lifetime without the need for battery substitution.

Compact eternal diffractive neural network chip for extreme environments

Artificial intelligence applications in extreme environments place high demands on hardware robustness, power consumption, and speed. Recently, diffractive neural networks have demonstrated superb advantages in high-throughput light-speed reasoning. However, the robustness and lifetime of existing diffractive neural networks cannot be guaranteed, severely limiting their compactness and long-term inference accuracy. Here, we have developed a millimeter-scale and robust bilayer-integrated diffractive neural network chip with virtually unlimited lifetime for optical inference. The two diffractive layers with binary phase modulation were engraved on both sides of a quartz wafer. Optical inference of handwritten digital recognition was demonstrated. The results showed that the chip achieved 82% recognition accuracy for ten types of digits. Moreover, the chip demonstrated high-performance stability at high temperatures. The room-temperature lifetime was estimated to be 1.84×1023 trillion years. Our chip satisfies the requirements for diffractive neural network hardware with high robustness, making it suitable for use in extreme environments.

Energy harvesting for unlimited lifetime systems

Energy harvesting for unlimited lifetime systems

Primary superconductivity in regular rotating electrically charged compact objects

In this paper, we refer to the early hypotheses on superconductivity in the models of the electron as an extended particle, and show how Nonlinear Electrodynamics minimally coupled to Gravity (NED-GR) predicts, without additional assumptions, the existence of primary superconductivity as the universal property of regular electrically charged rotating black holes and electromagnetic spinning solitons, replacing naked singularities and including that with the parameters of the electron. NED-GR dynamical equations describe basic generic properties of these objects in a self-consistent and the model-independent way, and establish the existence of the superconducting ring current in their deep interiors, which presents the non-dissipative source of the electromagnetic field of an object and provides its practically unlimited life time.

Powering for Long Term Monitoring in the Enclosed Areas

Paper presents possible solution and practical examples for wireless powering and signal transfer using the inductive coupling. It can be suitable for long term monitoring in enclosed areas and systems that are isolated form the surroundings. This solution allows avoiding the batteries. It can be used for probes bricked in to the wall, extreme temperature environment measurement, the barrels internal shells health monitoring etc. Main advantage of this kind of powering is nearly unlimited lifetime, no toxic pollutions (such as Cd, Li, H2SO4,… contained in the batteries) and universal applicability. The powering is provided by the near magnetic field. The resonance is considered in the design for increasing the voltage transfer. Also the passive signal transfer can be performed using this principle while it is similar to the RFID systems (Radio Frequency Identification). The main contribution of this paper is prediction of the powering potentialities and distance limits of this strategy. Voltage levels, power transfer efficiency and signal modulation effects are studied up to distance of 30 cm. The simple coils are considered. Also special converter principle is presented for this purpose.

Enhancing Network Lifetime of Duty Cycle-Based WSN With Mobile Sink Using Ambient Energy Harvesting

In order to guarantee a successful data collection process in wireless sensor networks with mobile sinks (WSN-MS), two primary objectives must be reached: 1) enabling the mobile sink to retrieve the maximum amount of data and 2) making sure that the network operates as long as possible. The first problem has been solved previously by proposing an innovative solution HXMAC. To address the second problem, on which this paper focuses, ambient energy harvesting is used to continuously supply power to each sensor node. Thus, this paper's main contribution is to propose EH-HXMAC (HXMAC with energy harvesting), which is based on all these improvements: seamless handover, duty cycling optimization, and mainly energy harvesting capability. EH-HXMAC has been evaluated using Cooja Contiki simulator. Obtained results based on the evaluation of the proposal EH-HXMAC clearly show its suitability as a good solution to promote unlimited lifetime for WSN-MS.

Scalable fabrication of MXene-based flexible micro-supercapacitor with outstanding volumetric capacitance

This work demonstrates a facile and reliable process for scalable and sustainable manufacturing of on-chip and flexible microsupercapacitor (MSC) devices for future applications in wearable/portable and miniaturized microelectronics. MSCs, which can provide high power density and a virtually unlimited lifetime, can be used as power supplies integrated into electronic systems. However, lower volumetric capacitance and energy density of conventional double-layer carbon supercapacitors limits their practical applications. In this study, a microfabrication process based on photolithography and a solution process were used to fabricate interdigitated micro-patterns of pristine MXene and 3D interconnected nanoporous MXene electrodes, which were then transferred onto flexible substrates. These flexible MSCs have properties that meet expectations for scalable manufacturing (107 chips in an 8 in.-wafer). They have an outstanding volumetric capacitance of 1,727F cm−3 (the highest ever reported for MXenes), desirable customization (essential at the 8-inch level of integrated microelectronics), and a remarkable energy density of 41.9 mWh cm−3, which is maintained at a high-power density of 26.8 W cm−3. Furthermore, the volumetric capacitance increased by approximately 140 % after 10,000 bending cycles, which was only observed in the planar interdigitated electrode micropatterns made of 2D MXene sheets and subjected to tensile stress on flexible polymer substrates.

Efficient dynamic control method of light polarization using single phase-only liquid crystal on silicon spatial light modulators for optical data storage.

The technology of five-dimensional (5D) optical data storage in transparent materials paves a promising way to unlimited lifetime data storage for future cloud use. Phase-only liquid-crystal-on-silicon spatial light modulators (LCOS SLMs) have already exhibited its potential for this application in tailoring ultrafast laser writing beams for 5D optical data storage. A phase-only LCOS SLM can generate arbitrary data patterns by using diffractive holographic imaging for data writing light beam generation. However, the polarization control of the output holographic image is still achieved by using an external polarization modulator, which leads to complications, bulkiness, and large delays in current methods. In this paper, we presented an efficient phase and polarization modulation method through a compact system based on a single phase-only LCOS SLM to simultaneously control both the holographic image and its polarization state. The proposed method utilizes two-polarization-component coding in conjunction with a polarization component rotation technique in a compact system. Using this polarization rotation technique, two light components can be independently coded by separately using two holograms on two halves of the LCOS SLM. We experimentally construct a proof-of-concept prototype of the compact system, and the effectiveness of the system has been experimentally verified.

Endurance testing and finite element simulation of a modified hip stem for integration of an energy harvesting system.

Instrumented implants are a promising approach to further improve the clinical outcome of total hip arthroplasties. For the integrated sensors or active functions, an electrical power supply is required. Energy harvesting concepts can provide autonomous power with unlimited lifetime and are independent from external equipment. However, those systems occupy space within the mechanically loaded total hip replacement and can decrease the life span due to fatigue failure in the altered implant. We previously presented a piezoelectric energy harvesting system for an energy-autonomous instrumented total hip stem that notably changes the original implant geometry. The aim of this study was to investigate the remaining structural fatigue failure strength of the metallic femoral implant component in a worst-case scenario. Therefore, the modified hip stem was tested under load conditions based on ISO 7206-4:2010. The required five million cycles were completed twice by all samples (n = 3). Additionally applied cycles with incrementally increased load levels up to 4.7 kN did not induce implant failure. In total, 18 million cycles were endured, outperforming the requirements of the ISO standard. Supplementary finite element analysis was conducted to determine stress distribution within the implant. A high stress concentration was found in the region of modification. The stress level showed an increase compared to the previously evaluated physiological loading situation and was close to the fatigue data from the literature. The stress concentration factor compared to the original geometry amounted to 2.56. The assessed stress level in accordance with the experimental fatigue testing can serve as a maximum reference value for further implant design modifications and optimisations.

Buffer-aided relay selection for secure communication in two-hop wireless networks with limited packet lifetime

Buffer-aided relay selection serves as one of the key approaches for achieving physical layer security (PLS) of wireless networks. Existing studies on buffer-aided relay selection mainly concentrate on the scenarios where transmitted packets have unlimited lifetime, while the more practical and important scenarios with limited packet lifetime remain largely unexplored. This paper therefore aims to study the buffer-aided relay selection for achieving PLS in two-hop wireless networks with limited packet lifetime. We first propose a novel buffer-aided relay selection scheme by carefully considering the remaining lifetimes of packets, conditions of available links and channel state information (CSI) of eavesdroppers. To model the security and reliability performances achieved by the proposed scheme, we then apply tools from the Markov chain theory to derive expressions of the secrecy outage probability (SOP) and the packet discarding probability (PDP) of the network, respectively. Finally, extensive simulation and numerical results are provided to illustrate the performances of our proposed scheme and our theoretical framework. The results show that although our scheme achieves a slightly higher SOP than the typical buffer-aided max-link relay selection scheme, it can greatly reduce the PDP of the network.

Industry 4.0 and Smart Production

Industry4.0 is a popular topic in today's ecosystem. Many businesses that have high profitability, sustainable unlimited lifetime and high efficiency will be able to integrate Industry 4.0 technologies, which emerged in Germany in 2011, into their businesses and meet changing customer demands. On the other hand, they will be able to gain competitive advantage with this new technology. The concept is defined as a process in which an advanced level of automation is applied over a virtual network, the machines make decisions by communicating with each other, the data collected with the help of sensors are stored in the cloud system through these virtual networks, and used by all stakeholders integrated into the system when needed. In this study, it is aimed to explain what the Industry 4.0 technologies conceptualized in 2011, the concept of smart production and the benefits of these technologies to businesses.

Cooperative Communication Between Two Transiently Powered Sensor Nodes by Reinforcement Learning

Energy harvesting (EH)-powered sensor nodes can achieve theoretically unlimited lifetime by scavenging energy from ambient power sources, such as radio-frequency (RF) and kinetic energy. The nodes can collect and transmit data wirelessly with the harvested energy. However, the transmission between two sensor nodes is successful only when both nodes have enough energy at the same time. While the receiver can be actively listening, it may deplete the energy long before the sender has accumulated enough energy. Thus, given the scarce, unpredictable, and unevenly distributed energy among sensor nodes, it is challenging to ensure efficient data transmission between them. To address this challenge, we propose a sensor node architecture with multiple radios, each with different energy consumption on the sender and receiver. A node can be put into sleep when charged up and wakes up for communication when it infers that both nodes have enough energy based on its observations. What is more, two nodes can cooperatively and dynamically select different radios according to the stored energy and historical information to maximize the data throughput. To achieve cooperative communication adaptively, the communication procedure is modeled as a cooperative Markov game with partial observability on each node, and multiagent reinforcement learning (MARL) is employed to achieve the best results. Experimental results on hardware prototype and by simulation show that the proposed approaches achieve up to 89.1% of the optimal throughput and significantly outperform other online algorithms.

CPEH: A Clustering Protocol for the Energy Harvesting Wireless Sensor Networks

In the last decade, energy harvesting wireless sensor network (EHWSN) has been well developed. By harvesting energy from the surrounding environment, sensors in EHWSN remove the energy constraint and have an unlimited lifetime in theory. The long‐lasting character makes EHWSN suitable for Industry 4.0 applications that usually need sensors to monitor the machine state and detect errors continuously. Most wireless sensor network protocols have become inefficient in EHWSN due to neglecting the energy harvesting property. In this paper, we propose CPEH, which is a clustering protocol specially designed for the EHWSN. CPEH considers the diversity of the energy harvesting ability among sensors in both cluster formation and intercluster communication. It takes the node’s information such as local energy state, local density, and remote degree into account and uses fuzzy logic to conduct the cluster head selection and cluster size allocation. Meanwhile, the Ant Colony Optimization (ACO) as a reinforcement learning strategy is utilized by CPEH to discover a highly efficient intercluster routing between cluster heads and the base station. Furthermore, to avoid cluster dormancy, CPEH introduces the Cluster Head Relay (CHR) strategy to allow the proper cluster member to undertake the cluster head that is energy depletion. We make a detailed simulation of CPEH with some famous clustering protocols under different network scenarios. The result shows that CPEH can effectively improve the network throughput and delivery ratio than others as well as successfully solve the cluster dormancy problem.

Effect of Normal Forces on the Electrical Endurance of Tin-Plated Contacts Under Elevated Temperature Fretting Conditions

In this article, an attempt is made to explore the effects of normal force and temperature on the threshold displacement amplitudes of tin-plated electrical contacts at elevated temperatures. Fretting tests were conducted at 323, 348, and 373 K at normal forces of 1, 1.25, 1.5, and 2 N. Riders and flats made from a 0.3-mm-thick brass sheet were coated with $10~\mu \text{m}$ of tin. Dimples were commonly found at the center of the contact area of the test specimens corresponding to an unlimited lifetime. In the testing temperature range, the threshold displacement amplitude decreases with an increase in the temperature and with a decrease in the normal force. In this range, the threshold displacement amplitude was found to be controlled by the oxidation of a tin-plated surface. The activation energy was found to be 7.5 kJ/mole, which is close to the value of the activation energy for the growth of tin oxide film. The threshold displacement amplitude can be represented in the form of an Arrhenius equation and is proportional to the normal force.

Review of MXene electrochemical microsupercapacitors

The rapid development of miniaturized and wearable electronics has stimulated growing needs for compatible miniaturized energy storage components. Owing to their unlimited lifetime and high-power density, miniaturized electrochemical capacitors (microsupercapacitors) are considered to be an attractive solution for the development of these microelectronics, but they often depend on the choice of electrode materials and fabrication protocols for scalable production. Recently, a new family of two-dimensional transition metal carbides, carbonitride and nitrides (referred to as MXenes) has shown great promise in advanced microsupercapacitors with high energy and power densities. This was achieved thanks to the high pseudocapacitance, metallic conductivity and ease of solution processing of MXene. In this review, recent progress on MXene synthesis, microstructure design, and fabrication strategies of MXene microsupercapacitors are discussed, and their electrochemical performance is summarized. Further, we briefly discuss the technical challenges and future directions.

On-the-fly particle metrology in hollow-core photonic crystal fibre.

Efficient monitoring of airborne particulate matter (PM), especially particles with aerodynamic diameter less than 2.5 µm (PM2.5), is crucial for improving public health. Reliable information on the concentration, size distribution and chemical characteristics of PMs is key to evaluating air pollution and identifying its sources. Standard methods for PM2.5 characterization require sample collection from the atmosphere and post-analysis using sophisticated equipment in a laboratory environment, and are normally very time-consuming. Although optical methods based on analysis of scattering of free-space laser beams or evanescent fields are in principle suitable for real-time particle counting and sizing, lack of knowledge of the refractive index in these methods not only leads to inevitable sizing ambiguity but also prevents identification of the particle material. In the case of evanescent wave detection, the system lifetime is strongly limited by adhesion of particles to the surfaces. Here we report a novel technique for airborne particle metrology based on hollow-core photonic crystal fibre. It offers in situ particle counting, sizing and refractive index measurement with effectively unlimited device lifetime, and relies on optical forces that automatically capture airborne particles in front of the hollow core and propel them into the fibre. The resulting transmission drop, together with the time-of-flight of the particles passing through the fibre, provide unambiguous mapping of particle size and refractive index with high accuracy. The technique offers unique advantages over currently available real-time particle metrology systems, and can be directly applied to monitoring air pollution in the open atmosphere as well as precise particle characterization in a local environment such as a closed room or a reaction vessel.

A lot sizing model for imperfect and deteriorating product with destructive testing and inspection errors

ABSTRACT Nowadays, the management and control of perishable inventories is important in many units and industrial enterprises. Perishable inventory management and control is more complex and challenging than inventories with unlimited lifetime. Hence determining the optimal inventory policies for these products is very important. In this paper, the optimal inventory policy for perishable products, produced in a system that manufactures prefect and imperfect items, using a sampling plan for accepting incoming lot is developed. The test used to ensure the quality of products is destructive and there are inspection errors. After developing a model for the problem and obtaining the objective function, first a simple algorithm is proposed to calculate the optimal order quantity. Then, the proposed model is validated using numerical examples after which sensitivity analysis is performed.

Exploration of the Kinetics of Toehold-Mediated Strand Displacement via Plasmon Rulers.

DNA/RNA strand displacement is one of the most fundamental reactions in DNA and RNA circuits and nanomachines. In this work, we reported an exploration of the dynamic process of the toehold-mediated strand displacement via core-satellite plasmon rulers at the single-molecule level. Applying plasmon rulers with unlimited lifetime, single-strand displacement triggered by the invader that resulted in stepwise leaving of satellite from the core was continuously monitored by changes of scattering signal for hours. The kinetics of strand displacement in vitro with three different toehold lengths have been investigated. Also, the study revealed the difference in the kinetics of strand displacement between DNA/RNA and DNA/DNA duplexes. For the kinetics study in vivo, influence from the surrounding medium has been evaluated using both phosphate buffer and cell lysate. Applying core-satellite plasmon rulers with high signal/noise ratio, kinetics study in living cells proceeded for the first time, which was not possible by conventional methods with a fluorescent reporter. The plasmon rulers, which are flexible, easily constructed, and robust, have proven to be effective tools in exploring the dynamical behaviors of biochemical reactions in vivo.

Дослідження структури рідкоскляного теплоізоляціоного матеріалу з використанням гранульованого наповнювача

Thermal insulation materials are among the most effective building materials, which can significantly reduce the consumption of materials and the cost of constructions. The purpose of thermal insulation is to limit the amount of heat transferred. Any fencing offers some resistance to heat transfer. However, to achieve significant thermal resistance, it is necessary either to make fencing of a large thickness, which is not economically feasible, or to use heat-insulating materials that can significantly reduce the thickness of the fencing. Recently, the tendency of replacing organic construction foams with inorganic ones - based on liquid glass - has become increasingly common in the world. Heat insulating materials based on liquid glass have low density and thermal conductivity, high porosity, the effective temperature range of their operation is from -20 °C to +600 °C, they are non-combustible, resistant to acids and their vapors, do not emit toxic substances, are not affected fungi and microorganisms, have an unlimited lifetime, which gives these materials advantages over combustible and toxic organic polymers, which, moreover, have a very limited lifetime. The foam properties are determined by its structural parameters, which, in turn, depend on the composition of the composition and the technology of the foaming process. In this paper there has been investigated the structure of block thermal insulation materials made on the basis liquid glass binding and granular filler, also made on the basis of liquid glass obtained by cold foaming using various blowing agents. There has been studied the effect of blowing agents and different ratio of granular filler to the binder to cross pore diameter, coefficient of shape and degree of heterogeneity structure of the blocks. When investigating the structure of insulation materials, it was found that the best gas-forming agent is aluminum powder. The samples obtained with its use are characterized by high porosity, which positively affects the thermal insulation characteristics of the material, and rather high strength indicators, which allows the material to be transported without significant damage. The introduction of granular filler into the composition contributes to the formation of a more even and durable structure of the heat-insulating material. Pores of this material are mostly closed, evenly distributed throughout the volume.

(Invited) Wearable Sensor Systems for Long Term Health and Environmental Monitoring

The role of health care continues to be one of the biggest global challenges. Numerous countries are grappling with how to provide effective, yet low cost health care for its citizens. Much of the cost associated with healthcare arise from chronic diseases (heart disease, respiratory disease, diabetes, etc.). With minimal focus on prevention, proper lifestyle, role of environment (known to impact respiratory diseases and cancers), and limited early diagnosis and management, we are now in a situation where one in three Americans suffer from chronic conditions and most Americans over the age of 65 suffer from multiple chronic conditions. This situation presents a huge burden to health care costs and leads to poor quality of life for our citizens. Advanced wearable health platforms have the potential of providing monitoring of an individual’s critical health parameters and their personal environmental exposure in a reliable, accurate, long-term/continuous, hassle-free manner can create a paradigm shift in chronic disease management. Long term monitoring of multiple health and environmental sensors, enabled by ultra-low power electronics and energy harvesting, can have many disruptive benefits. They can: i) prevent negative outcomes by vigilantly monitoring conditions such as arrhythmia, heart rate variability (HRV), epilepsy, etc., ii) provide constant feedback to users on their lifestyle choices, e.g., exercise on wellness/biochemical stress, diet on glycemic index, and more, iii) enable an understanding of the relationship between health and environmental toxins, e.g., ozone and asthma, particulates, and heart rate variability, iv) build personalized health databases for individuals that span years and even decades, e.g., blood pressure variation, and v) predict onset of life threatening health conditions using data analytics and longitudinal data. This talk will present the work being carried out in the NSF funded Engineering Research Center for Advanced Self-Powered Systems of Integrated Sensors and Technology (ASSIST) to to build disruptive health platforms that are wearable, wireless, comfortable, powered by the human body, and consist of multimodal health and environment sensors. In this effort, power is being harvested from the human body in the form of heat and movement/strain and utilized very effectively using subthreshold CMOS computation and ultra low power novel radios. In addition, ASSIST is building medically validated low-power health sensors (EKG, hydration, pulse-oximetry, biochemical markers such as cortisol and even personal environmental exposures to toxins such as ozone (related to Asthma triggers) that go much further than simple activity monitoring and provide a significantly more sophisticated understanding of human health due to correlation of multiple/heterogeneous data streams. This combination of harvesting power from the human body and using it effectively using low power logic/radios and sensors enable “forever” powering of sensors by small energy harvesters. Ultimately, these sensor systems with their miniature form factors, unlimited operating lifetime, reliable sensors for health and wellness supported by infrastructure on ubiquitous mobile platforms that convert data to actionable information have the potential of creating a paradigm shift in future global health. Access to this level of individual health data can revolutionize medical practices, decrease need for hospital admissions, reduce length of hospital stays and hospital readmissions, facilitate rapid diagnosis and effective treatment decisions. These ASSIST technologies can cause disruptive changes in the implementation of the exploding wearable health space and enable society to transition to wellness.