Efficient Energy Delivery Research Articles

A Comparison of Double Poling Physiology and Kinematics Between Long-Distance and All-Round Cross-Country Skiers.

PurposeThe objective of this study was to compare physiological and kinematic responses to double poling (DP) between long-distance (LDS) and all-round (ARS) cross-country skiers.MethodsA number of five world-class LDS (28.8 ± 5.1 years, maximal oxygen uptake (VO2max): 70.4 ± 2.9 ml·kg−1·min−1) and seven ARS (22.3 ± 2.8 years, VO2max: 69.1 ± 4.2 ml·kg−1·min−1) athletes having similar training volumes and VO2max performed three identical tests; (1) submaximal and incremental tests to exhaustion while treadmill DP to determine gross efficiency (GE), peak oxygen uptake (DP-VO2peak), and peak speed; (2) submaximal and incremental running tests to exhaustion to determine GE, VO2max (RUN-VO2max), and peak speed; and (3) an upper-body pull-down exercise to determine one repetition maximum (1RM) and peak power. Physiological responses were determined during both DP and running, together with the assessments of kinematic responses and electromyography (EMG) of selected muscles during DP.ResultsCompared to ARS, LDS reached higher peak speed (22.1 ± 1.0 vs. 20.7 ± 0.9 km·h−1, p = 0.030), DP-VO2peak (68.3 ± 2.1 vs. 65.1 ± 2.7 ml·kg−1·min−1, p = 0.050), and DP-VO2peak/RUN-VO2max ratio (97 vs. 94%, p = 0.075) during incremental DP to exhaustion, as well as higher GE (17.2 vs. 15.9%, p = 0.029) during submaximal DP. There were no significant differences in cycle length or cycle rate between the groups during submaximal DP, although LDS displayed longer relative poling times (~2.4% points) at most speeds compared to ARS (p = 0.015). However, group × speed interaction effects (p < 0.05) were found for pole angle and vertical fluctuation of body center of mass, with LDS maintaining a more upright body position and more vertical pole angles at touchdown and lift-off at faster speeds. ARS displayed slightly higher normalized EMG amplitude than LDS in the muscles rectus abdominis (p = 0.074) and biceps femoris (p = 0.027). LDS performed slightly better on 1RM upper-body strength (122 vs. 114 kg, p = 0.198), with no group differences in power in the pull-down exercise.ConclusionsThe combination of better DP-specific aerobic energy delivery capacity, efficiency, and technical solutions seems to contribute to the superior DP performance found among specialized LDS in comparison with ARS.

Revision and Replacement of Spinal Cord Stimulator Paddle Leads

ObjectivesPaddle leads for spinal cord stimulation (SCS) offer more efficient energy delivery and advantages in some patients. However, there is concern for how safely SCS paddles can be replaced once previously implanted because of scar tissue and the relative vulnerability of the thoracic cord. In this study, we share our experience on SCS paddle replacement. Materials and MethodsParticipants who underwent SCS replacement at Albany Medical Center between 2011 and 2020 were identified. The medical records were reviewed for demographic data and information regarding initial complications, reason for removal or revision, subsequent complications of replacement surgery and its timing, and whether the implant was ultimately removed. Percutaneous lead replacement cases performed over the same period were used as a comparison group. ResultsA total of 1265 patients were identified to have had an SCS-related procedure based on billing codes. Of these, 73 involved replacement of epidural leads (51 paddles, 22 percutaneous). Most paddles (48/51) were replaced at the time of removal. A total of 30 of the 51 paddle replacements required additional lamina removal. Re-operations that occurred more than one year after initial implant were significantly more likely to require additional bone removal (p < 0.001). Paddle re-operations lasted in general 1.7 ± 0.2 hours and had 35 ± 5 mL of blood loss, whereas percutaneous operations lasted 1.3 ± 0.2 hours and had 12.5 ± 2 mL of blood loss. Despite the invasive nature of paddle replacement, there was no difference in complications (p = 0.23) compared with that in percutaneous leads. ConclusionsThis study characterizes the safety profile of SCS paddle replacement surgeries. Here, we demonstrate that the replacement of paddle leads at the time of removal, with additional lamina removal if needed because of scar, is associated with low rates of complications. This validates the feasibility and low-risk profile of replacing paddle leads when clinically indicated for experienced surgeons with specialization in SCS.

Optimizing nanostructured TiO2/Cu2O pn heterojunction solar cells using SCAPS for fourth industrial revolution

This study aims to optimize nanostructured TiO2/Cu2O pn heterojunction solar cells using Solar Cell Capacitance Simulator (SCAPS) to aid in clean, efficient and affordable energy delivery in readiness for industry 4.0. A clean, affordable and efficient energy affordable is crucial for the success of industry 4.0. The challenges of expensive and interrupted power supply still exist in some developing countries. Solar energy is capable of solving this challenge. Different research now looks at reducing the cost of solar energy to aid domestication. This study simulated an alternate material (metal oxide) to silicon solar cells. A working input of 300 K was used for the as-deposited and compared with air and nitrogen annealed (423.15 K) of the heterojunction. Additional working parameters involves sunlight represented by illumination of AM 1.5G with a 500 W Xenon lamp, the electrode/contact was represented by silver. The thickness of the absorber layer was 2000 nm and buffer layer was 200 nm. An improved efficiency was obtained for annealed samples compared to the as-deposited TiO2/Cu2O pn heterojunction efficiency of 1.25%. The fill factor of samples annealed in air was 49.5%, efficiency was 3.23%, and nitrogen annealed was 53.50% for fill factor and 3.85% for efficiency. This result will contribute to the investigation and fabrication of metal oxide based solar cells especially in developing countries.

WiFED Mobile: WiFi Friendly Energy Delivery With Mobile Distributed Beamforming

Wireless RF energy transfer for indoor sensors is an emerging paradigm ensuring continuous operation without battery limitations. However, high power radiation within ISM band interferes with packet reception for existing WiFi devices. The paper proposes the first effort in merging RF energy transfer within a standards compliant 802.11 protocol, realizing practical and WiFi-friendly Energy Delivery with Mobile Transmitters (WiFED Mobile). WiFED Mobile architecture is composed of a centralized controller coordinating the actions of multiple energy transmitters (ETs), and deployed sensors that periodically requires charging. The paper first describes 802.11 supported protocol features that can be exploited by sensors to request energy and for ETs to participate in energy transfer. Second, it devises a controller-driven bipartite matching algorithm, assigning appropriate number of ETs to sensors for efficient energy delivery. Thirdly, it detects outlier sensors (OS), which have limited power reception from static ETs and utilizes mobile ETs (METs) to satisfy their charging cycles. The proposed in-band and protocol supported coexistence in WiFED Mobile is validated via simulations and partly in a software defined radio testbed, showing that METs reduce latency by 42% and improve throughput by 83% in scenarios where using only static ETs fails to satisfy charging cycles of OS.

Unidirectional coherent energy transport via conjugated oligo(p-phenylene) chains.

We discovered a way to funnel high-frequency vibrational quanta rapidly and unidirectionally over large distances using oligo(p-phenylene) chains. After mid-IR photon photoexcitation of a -COOH end group, the excess energy is injected efficiently into the chain, forming vibrational wavepackets that propagate freely along the chain. The transport delivers high-energy vibrational quanta with a range of transport speeds reaching 8.6 km/s, which exceeds the speed of sound in common metals (∼5 km/s) and polymers (∼2 km/s). Efficiencies of energy injection into the chain and transport along the chain are found to be very high and dependent on the extent of conjugation across the structure. By tuning the degree of conjugation via electronic doping of the chain, the transport speed and efficiency can be controlled. The study opens avenues for developing materials with controllable energy transport properties for heat management, schemes with efficient energy delivery to hard-to-reach regions, including transport against thermal gradients, and ways for initiating chemical reactions remotely.

A review of antenna designs for percutaneous microwave ablation.

Microwave (MW) antenna is a key element in microwave ablation (MWA) treatments as the means that energy is delivered in a focused manner to the tumor and its surrounding area. The energy delivered results in a rise in temperature to a lethal level, resulting in cell death in the ablation zone. The delivery of energy and hence the success of MWA is closely dependent on the structure of the antennas. Therefore, three design criteria, such as expected ablation zone pattern, efficiency of energy delivery, and minimization of the diameter of the antennas have been the focus along the evolution of the MW antenna. To further improve the performance of MWA in the treatment of various tumors through inventing novel antennas, this article reviews the state-of-the-art and summarizes the development of MW antenna designs regarding the three design criteria.

IoT based Smart Grid Attack Resistance in AC and DC State Estimation

Use of automation and intelligence in smart grids has led to implementation in a number of applications. When internet of things is incorporated it will result in the significant improvement a number of factors such as fault recovery, energy delivery efficiency, demand response and reliability. However, the collaboration of internet of things and smart grid gives rise to a number of security issues and threats. This is especially the case when using internet based protocols and public communication infrastructure. To address these issues we should ensure that the data stored is secure and critical information from the data is extracted in a careful manner. If any threat to its security is detective an early blackout warning should be issued immediately. In this paper we have proposed a geometric view point for big data attacks which is capable of bypassing bad data detection. We have created an environment where replay scheme is used launch blind energy big data attack. The defence mechanism of our proposed work is studied and found to be efficient. Experimental evidence supports our theory and we have found our methodology to efficiently improve error detection rate.

Artificial intelligence techniques for stability analysis and control in smart grids: Methodologies, applications, challenges and future directions

Smart grid is the new trend for clean, sustainable, efficient and reliable energy generation, delivery and use. To ensure stable and secure operation is essential for the smart grid, which needs effective stability analysis and control. As the smart grid has evolved through a growing scale of interconnection, increasing integration of renewable energy, widespread operation of direct current power transmission systems, and liberalization of electricity markets, the stability characteristics of it are much more complex than the past. Due to these changes, conventional stability analysis and control approaches have a series of drawbacks in terms of speed, effectiveness and economy. On the contrary, the emerging artificial intelligence (AI) techniques provide powerful and promising tools for stability analysis and control in smart grids and have attracted growing attention. This paper aims to give a comprehensive and clear picture of recent advances in this research area. First, we present a general overview of AI, including its definitions, history and state-of-the-art methodologies. And then, this paper gives a comprehensive review of its applications to security assessment, stability assessment, fault diagnosis, and stability control in smart grids. These applications have achieved impressive results. Nevertheless, we also identify some major challenges these applications face in practice: high requirements on data, imbalanced learning, interpretability of AI, difficulties in transfer learning, the robustness of AI to communication quality, and the robustness against attack or adversarial examples. Furthermore, we provide suggestions for potential important future investigation directions to overcome these challenges and bridge the gap between research and practice.

Optimization design of a new type of high-frequency piezoelectric ultrasonic transducer with the compliant hinge-based mounting clamp

Piezoceramic-based ultrasonic transducers are widely used in the fabrication and packaging of the microelectronic device and their performance largely depends on the ultrasonic energy delivery efficiency (UEDE) which can be reflected by the tip vibration amplitude output (TVAO) of the transducer indirectly. Recently, it was reported that a new type of flexure hinge-based mounting clamp could enhance the TVAO of the transducer significantly. To get the best effect, this research aimed at developing an optimization method for this newly proposed mounting clamp. For the purpose, a series of researches were performed against a self-developed transducer equipped with a pair of circular notched hinge-based mounting clamps. Firstly, the influential rules of several key geometric parameters of the flexure hinge on the TVAO of the ultrasonic transducer were explored. Then, an optimization objective function together with a group of constraints was constructed. Next, the Particle Swarm Optimization (PSO) algorithm was used to optimize the geometric parameters of the circular hinge-based mounting clamp. Finally, the performance of the optimized mounting clamp was tested based on a measurement and evaluation system. The results show the optimized mounting clamp can enhance the TVAO of the transducer greatly, presenting a good improvement effect of the UEDE, and manifesting the feasibility and effectiveness of the developed method.

Time-gated iterative phase conjugation for efficient light energy delivery in scattering media.

Light waves propagating through complex biological tissues are spatially spread by multiple light scattering, and this spread limits the working depth in optical bioimaging, phototherapy, and optogenetics. Here, we propose the iterative phase conjugation of time-gated backscattered waves for enhancing the light energy delivered to a target object embedded in a scattering medium. We demonstrate the enhancement of light energy delivered to a target object hidden behind a 200-µm-thick mouse skull by more than ten times in comparison with the initial random input. The maximum enhancement was reached in only 10 iterations, more than a hundred times smaller than existing methods based on either a time-gated reflection matrix or iterative feedback optimization of the time-gated reflection intensity. Consequently, the proposed method is less sensitive to sample perturbations. Furthermore, the number of images required for optimization remained almost unchanged with an increase in the illumination area, unlike existing methods, where the convergence time scales with the illumination area. The proposed method provides high operation speed over a wide illumination area, which can facilitate the use of wavefront shaping in practical applications.

Efficient Energy Delivery System of the CHP-PV Based Microgrids with the Economic Feasibility Study

AbstractA comprehensive theoretical investigation validated by the measurement is necessary to assess the impact of a microgrid on the electric distribution system. Some key parameters worth investigating are- enhancing economy, reliability, quality, and resiliency of a microgrid. Considering this necessity, a study of energy delivery system in a microgrid and its financial feasibility to integrate into the energy infrastructure has been presented in this paper. A campus microgrid with energy-efficient combined heat and power (CHP) natural gas-fired microturbine and photovoltaic generation has been used as a testbed to evaluate the efficiency of the power delivery. With distributed control and communication capability, this microgrid can be considered as a building block of smart grid that facilitates the inclusion of renewable and energy-efficient distributed generation. Simulation work has been performed to study the economic feasibility to integrate such microgrid into the energy grid. Several cases of remote microgrid operation have been studied to compare the best possible solution.

Harmonic excitation response performance and active regulation of the high-frequency piezoelectric ultrasonic transducer used in the thermosonic bonding for microelectronics

High-frequency piezoelectric ultrasonic transducer is one of the most important components in the modern thermosonic bonding for microelectronics and its harmonic excitation response performance can vary due to many reasons, often leading to a mutable bonding quality. In this research, an in-depth understanding of the harmonic excitation response performance of the transducer was provided. Relying on the electromechanical equivalent method and a series of experimental investigations, the main influential factors of the response performance, and the relevant rules were explored and analyzed. Then, the percentage peak overshoot and settling time were extracted from the exciting response signal and viewed as two basic morphological feature parameters to characterize the response performance. To regulate the exciting response performance actively and get the desired ultrasonic energy delivery efficiency, a new method based on radial basis function neural network was developed and it could predict the resonant frequency and the settling time accurately when the excitation condition of the transducer was changed. Test results manifest the newly proposed method is feasible and efficient, and it also can be used to the ultrasonic transducers in other applications.

Iterative optimization of time-gated reflectance for the efficient light energy delivery within scattering media.

In complex media, light waves are diffused both in space and time due to multiple light scattering, and its intensity is attenuated with the increase of propagation depth. In this paper, we propose an iterative wavefront shaping method for enhancing time-gated reflection intensity, which leads to efficient light energy delivery to a target object embedded in a highly scattering medium. We achieved an over 10 times enhancement of reflectance at the specific flight time and demonstrated the focusing of light energy to the target object. Since the proposed method does not require reflection matrix measurement, it will be highly suited to samples in mechanically dynamic conditions.

V02-08 A COMPARISON OF TRADITIONAL HOLMIUM AND MOSES LASERS FOR PROSTATIC ENUCLEATION IN A SINGLE PATIENT

INTRODUCTION AND OBJECTIVES:Holmium laser enucleation of the prostate (HoLEP) has become a therapeutic mainstay for prostatic obstruction, particularly for larger glands. The technique has been found to be durable and effective despite some limitations such as operative time and learning curve. The Moses laser fiber produced by Lumenis (Yokneam, Israel) is a novel technology that provides more efficient energy delivery to a target structure by decreasing water absorption of the beam. Though prior research has shown benefit of the technology as applied to stone surgery, there have been no reports of utilizing the Moses laser for prostatic enucleation. We sought to subjectively evaluate Moses laser enucleation of the prostate (MoLEP) as a novel alteration to HoLEP.METHODS:Prostatic enucleation was performed in a single patient by a single surgeon. The prostate was removed in two sections, divided by left and right prostatic lobes. Traditional holmium laser was used for the patient's right lobe, while the Mo...

Layered CuI-MOFs containing [Mo8O26]4− clusters as supercapacitor electrode materials

We have successfully synthesized two kinetically stable CuI-MOFs with 2D layered architectures by introduction of β-[Mo8O26]4− clusters, denoted as [CuI2(β-Mo8O26)(bnie)2][Cu2(bnie)2] (NAU-1) and [CuI2(bnie)2]2(β-Mo8O26) (NAU-2) respectively. According to the result of electrochemical analysis, all these framework active materials behave as pseudo-capacitor and exhibit high capacitance and excellent energy delivery efficiency. For instance, the maximum gravimetric capacitance of NAU-1 and NAU-2 electrode is 800 and 828 F g−1 at a current density of 1.0 A g−1 separately. Theory mechanism analyses suggest capacitive (i ∝ v) and diffusion-controlled (i ∝ v1/2) currents contribute equally during redox reaction process. Particularly, after integration of carbon-based conductive matrix with CuI-MOFs, the structural stability and cycling life are both promoted. Whether carbon nanotubes or graphene oxide, they both boost the conductivity of the electrode and the capacitance retentions of these electrodes keep growing trends that all surpass 100% after 5000 continuous cycles. The excellent electrochemical performance may be ascribed to the β-[Mo8O26]4− clusters occupying the void space of 2D layered structures that facilitate electron transport and ions transmission.

Mechanochemical synthesis of poly(lactic acid) block copolymers: overcoming the miscibility of the macroinitiator, monomer and catalyst under solvent-free conditions

Efficient mixing and energy delivery by ball-milling promoted the lactide polymer growth from macroinitiators without the use of a solvent.

Oncological hyperthermia: The correct dosing in clinical applications.

The problem with the application of conventional hyperthermia in oncology is firmly connected to the dose definition, which conventionally uses the concept of the homogeneous (isothermal) temperature of the target. Its imprecise control and complex evaluation is the primary barrier to the extensive clinical applications. The aim of this study was to show the basis of the problems of the misleading dose concept. A clear clarification of the proper dose concept must begin with the description of the limitations of the present doses in conventional hyperthermia applications. The surmounting of the limits the dose of oncologic hyperthermia has to be based on the applicability of the Eyring transition state theory on thermal effects. In order to avoid the countereffects of thermal homeostasis, the use of precise heating on the nanoscale with highly efficient energy delivery is recommended. The nano-scale heating allows for an energy-based dose to control the process. The main aspects of the method are the following: i) It is not isothermal (no homogeneous heating); ii) malignant cells are heated selectively; and iii) it employs high heating efficacy, with less energy loss. The applied rigorous thermodynamical considerations show the proper terminology and dose concept of hyperthermia, which is based on the energy-absorption (such as in the case of ionizing radiation) instead of the temperature-based ideas. On the whole, according to the present study, the appropriate dose in oncological hyperthermia must use an energy-based concept, as it is well-known in all the ionizing radiation therapies. We propose the use of Gy (J/kg) in cases of non-ionizing radiation (hyperthermia) as well.

Development of a microwave stunning system for cattle 2: Preliminary observations on behavioural responses and EEG

DTS: Diathermic Syncope® (DTS) is a novel system for rendering animals insensible prior to slaughter, utilizing microwave energy to induce a rise in temperature in the brain to a point at which the animal is expected to lose consciousness. During development and optimisation of the system, two trials were carried out utilizing non-anaesthetized adult cattle, to gather data on behavioural outcomes and EEG changes following energy application. In trial1, ten cattle received DTS treatments (high energy >290 kJ, n = 3; low energy <200 kJ, n = 4; and intermediate 200 < 290 kJ, n = 3), and seven received captive bolt stunning, prior to exsanguination. In trial 2, following improvements to the efficiency of energy delivery, 20 cattle received DTS (200–360 kJ). Post treatment EEG was characterized by seizure-like activity and reductions in 95% spectral edge and median frequencies; with EEG suppression persisting for at least 80 s up to over 4 min post treatment application. Animals showed: Loss of posture, Loss of corneal responses; Loss of withdrawal response (pinprick); Eye staring, not following movement. The animals remained unresponsive to stimuli for up to 4 min post DTS, and behavioural expression of distress was not observed. Seventeen of the 30 animals showed indications of returning reflex responses after 100 s post treatment, suggesting that animals receiving lower energy applications may recover from the stun.

Indoor environment monitoring based on humidity conditions using a low-cost sensor network

Strict energy targets are driving demands for greener and more sustainable energy generation, distribution and consumption practices. A significant portion of energy consumption is due to the use of heating, ventilation and air-conditioning (HVAC) systems within building. Optimising HVAC systems for energy efficiency requires improved environmental monitoring; as such more sensors are necessary for monitoring the indoor space. However, use of multiple sensors could be cost prohibitive, hence the need for low-cost sensor network systems. This paper presents a low-cost monitoring system and the testing of the system on humidity conditions, which is an important parameter affecting thermal comfort conditions in the indoor environment and by extension, energy consumption and/ or conservation. We argue that appropriately monitoring and reporting on indoor environment conditions helps to ensure appropriate application of control measures leading to efficient energy management and delivery. The system, with some modification and further development can also be used to monitor and control Mini/Microgrid systems or in other fields.

Mechanochemical Post-Polymerization Modification: Solvent-Free Solid-State Synthesis of Functional Polymers.

Mechanochemical postpolymerization modification is reported herein. The fast and efficient synthesis of a library of macromolecules with functional diversity and structural uniformity was realized without a solvent by means of a high speed ball-milling technique. A series of polymers prepared from 4-vinylbenzaldehyde (4-VBA) underwent solid-state Schiff base formations with a series of amines and amine derivatives. The efficient mixing and energy delivery provided by the collisions between balls not only promoted rapid imine formation but also eliminated the need for a chemical solvent, which is highly desirable for green chemical synthesis.