Max Output Power Research Articles

Experimental passive and reactive control of a Laboratory Scale WEC Point Absorber

Scaled testing is an important and valuable step in the process of determining best practices of WEC development, validating numerical models of WEC systems, and/or preparing for larger scale testing. Validation and verification of numerical models are very important as there are physical phenomena that are hard to numerically model such as non-linear frictional effects. This paper builds on the 2021 EWTEC paper [1] in performing and evaluating experimental testing of the Laboratory Upgrade Point Absorber (LUPA). Since this last paper, LUPA has been fabricated and deployed and an initial characterization has been performed. Particularly passive (damping), and reactive (damping and stiffness) control methodologies are employed in regular waves to characterize and evaluate the mechanical power extracted from the waves. Reactive control allows us to invest energyin the system to get a greater average energy out as compared to damping control.
 The LUPA project has just finished its first deployment in the Large Wave Flume at the O.H. Hinsdale Wave Research Laboratory at Oregon State University as shown in Figure 1. Three modes of operation were tested, namely one body heave only, two body heave only, and six degrees of freedom. The one body heave only mode restricts the motion to linear and vertical and fixes the spar body so that the float is the only body free to move. The two body heave only maintains the vertical linear motion, but unlocks the float such that the float and spar are free to heave. The six degrees of freedom case is a floating moored mode with no restrictions on motion.
 This paper will focus on comparing passive and reactive control for the one body heave only case and the six degreesof freedom case with preliminary results shown in Figure 2. Regular waves were tested, focusing on a single wave heightand sweeping the wave period. Results will be presented in power (W) units and in capture width (m). Fig. 2. Top shows max power output vs input wave period for one body and two body configurations and just damping and damping and stiffness cases.Take note of differing input wave height. Bottom shows capture width.
 The LUPA project will provide a valuable testing platform for students and researchers. It will also provide a publicly available open source design and dataset for the research community here: https://github.com/PMECOSU/LUPA. This paper will serve as documentation of the initial testing of the system, providing baseline control results to be compared in future testing.

Exercise-induced Oxidative Stress During Exercise And Recovery In Hot Condition

Acute exercise of sufficient intensity and duration can result in oxidative stress (OS), characterized by elevated blood OS biomarkers. Unfortunately, the time course for the change in OS and its recovery (RC) has not been adequately determined in most studies. PURPOSE: This study investigated the pattern change in blood OS biomarkers (low density lipoproteins oxidized (LDLox) and glutathione ratio (oxidized glutathione (GSSG) to total glutathione (TGSH) during a 1 h bout of cycling and a 1 h RC period, compared to a rest condition. It was hypothesized that the blood OS biomarkers would be elevated within the first 30 min of exercise based on the predicted intensity with the OS biomarkers returning to baseline during RC. METHODS: Ten males (mean(SD)); age,24.4 (1) yrs; mass, 75.3 (2.1) kg; height 175.9 (1) cm; VO2max, 50.0 (1.8) ml·kg-1·min-1) arrived at 1800 h on two occasions and completed; an exercise (Ex) (70-75% max power output) or rest (RE) condition in a hot environment (40oC and 30% relative humidity), in a randomized order. Blood was sampled every 15 min during EX and at min 15, 30 and 60 mins during RC. Plasma LDLox and both reduced (GSH) and oxidized (GSSG) forms of glutathione status were assessed. Repeated measures ANOVAs (2 conditions x 4 times [EX] and 2 conditions x 4 times [RC]) determined if differences in LDLox, and GSSG/TGSH ratio occurred with an alpha set a priori p < .05. RESULTS: Mean HR for RE was 73 ± 3 bpm vs 165 ± 3 for EX overtime. Mean cycling power output was 151 ± 9 W during EX. There was no main effect for condition (p = 0.054) or time (p = 0.061) or interaction (time by condition) effect (p = 0.074) for LDLox during EX. The GSSG/TGSH ratio increased at 30 minutes regardless of condition (12.5% compared to 5% at 0 minutes in chamber). The GSSG/TGSH ratio had a main effect for time to increase at 60 min RC independent of condition (p = 0.02). CONCLUSIONS: The results did not support our hypothesis of an exercise-induced OS. Our findings were likely impacted by 1) the environmental conditions inducing a high heat stress at rest, 2) delayed recovery due to the high heat stress in combination with dehydration during recovery, and 3) and small sample size which could not overcome the large interindividual variability in LDLox values.

Fabrication and optical properties of Tm3+/Ho3+ co-doped lanthanum aluminosilicate photonic crystal fiber for 2 μm fiber lasers

In this study, the Tm3+/Ho3+ co-doped lanthanum aluminosilicate glass was prepared using the melt-quenching method. The absorption and emission properties of glass were studied. A Tm3+/Ho3+ co-doped lanthanum aluminosilicate photonic crystal fiber (PCF) was fabricated using the stacking and drawing method. The PCF structure effectively enhanced the laser performance and generated laser emission centered at 2051 nm. The max output power of the PCF laser was 256 mW under existing conditions and the optical-to-optical efficiency was 6.37%. In addition, the broadband luminescence characteristics strongly influenced by the length of fibers were presented. The results indicated that the Tm3+/Ho3+ co-doped lanthanum aluminosilicate PCF could be potentially used for 2 μm fiber lasers and amplifiers.

Beam–Wave Resynchronization Method of the Nonperiodic Meander Line and Folded-Waveguide SWS for TWTs

A beam-wave resynchronization (BWRS) method is proposed by changing the structural parameters of the nonperiodic (NP) slow wave structure (SWS) to reduce the phase velocity of the wave for traveling-wave tubes (TWT) application. The mathematical model and analysis for the BWRS method are introduced to investigate what condition the NP meander line SWS (ML-SWS) and the NP folded-waveguide SWS (FW-SWS) should satisfy so that the corresponding TWT can have a good output performance. As the applications, the NP zigzag ML-SWS and the concentric arc FW-SWS are designed according to the method, which is also compared with that designed according to the phase velocity synchronization (PVS). The simulated results show that, by using the BWRS method, the max output power (efficiency) of the zigzag ML-SWS TWT can be improved from 56.7 (18.9%) to 76.26 W (25.4%), and the bandwidth can be expanded from 6 to 10 GHz in the Ka-band. Furthermore, the max output power (efficiency) of the concentric arc FW-SWS TWT can be improved from 199 (27.6%) to 237 W (32.9%), and the bandwidth can be expanded more than twice in the W-band as before. These results indicate that the BWRS method is beneficial for the improvement of the output power and electron efficiency and may be beneficial for wider bandwidth.

Acute and Chronic Citrulline Malate Supplementation on Muscle Contractile Properties and Fatigue Rate of the Quadriceps.

This study compared the acute and chronic impact of citrulline malate (CM) supplementation on muscle contractile properties and fatigue rate of the quadriceps. Eighteen recreationally trained males consumed both a placebo (PL) and CM treatment for two separate dosing periods. The first experimental testing session for each dosing period was considered the baseline day, the second session the acute day, and the third session the chronic day, which followed seven consecutive days of supplementation. All testing sessions included exercising on a cycle ergometer at 50%-60% of their max power output for 30min followed by performing the Thorstensson test on an isokinetic dynamometer. A two-way (Supplement × Time) analysis of variance with repeated measures resulted in no significant interactions (p > .05) (PL: baseline day, acute day, chronic day vs. CM: baseline day, acute day, chronic day) for peak power (in watts) (469 ± 81, 490 ± 97, 502 ± 99 vs. 464 ± 85, 480 ± 103, 501 ± 81); peak torque (in newton meters) (150 ± 26, 157 ± 32, 161 ± 31 vs. 149 ± 27, 156 ± 33, 161 ± 26); fatigue rate (in percentage) (57 ± 9, 57 ± 10, 58 ± 9 vs. 57 ± 10, 56 ± 9, 58 ± 9); and heart rate (in beats per minute) (156 ± 17, 146 ± 13, 146 ± 9 vs. 155 ± 11, 146 ± 11, 146 ± 9). The results of this study suggest that neither acute nor chronic supplementation of CM had an effect on recovery or fatigue rate of the quadriceps.

Ultrasonic cavitation at liquid/solid interface in a thin Ga–In liquid layer with free surface

Cavitation in thin layer of liquid metal has potential applications in chemical reaction, soldering, extraction, and therapeutic equipment. In this work, the cavitation characteristics and acoustic pressure of a thin liquid Ga–In alloy were studied by high speed photography, numerical simulation, and bubble dynamics calculation. A self-made ultrasonic system with a TC4 sonotrode, was operated at a frequency of 20 kHz and a max output power of 1000 W during the cavitation recording experiment. The pressure field characteristic inside the thin liquid layer and its influence on the intensity, types, dimensions, and life cycles of cavitation bubbles and on the cavitation evolution process against experimental parameters were systematically studied. The results showed that acoustic pressure inside the thin liquid layer presented alternating positive and negative characteristics within 1 acoustic period (T). Cavitation bubbles nucleated and grew during the negative-pressure stage and shrank and collapsed during the positive-pressure stage. A high bubble growth speed of 16.8 m/s was obtained and evidenced by bubble dynamics calculation. The maximum absolute pressure was obtained at the bottom of the thin liquid layer and resulted in the strongest cavitation. Cavitation was divided into violent and weak stages. The violent cavitation stage lasted several hundreds of acoustic periods and had higher bubble intensity than the weak cavitation stage. Cavitation cloud preferentially appeared during the violent cavitation stage and had a life of several acoustic periods. Tiny cavitation bubbles with life cycles shorter than 1 T dominated the cavitation field. High cavitation intensities were observed at high ultrasonication power and when Q235B alloy was used because such conditions lead to high amplitudes on the substrate and further high acoustic pressure inside the liquid.

Validity Of The Session Rpe For Detecting Accumulated Fatigue

Studies have shown that the ratio of blood lactate concentration to Rating of Perceived Exertion (HLa/RPE) and session RPE (sRPE) may be considered useful to detect overreaching and accumulated fatigue. However, no study has investigated their relationship. PURPOSE: To examine the relationship between HLa/RPE and sRPE during a period of intensified training. METHODS: Twelve young adults performed incremental exercise to assess their max power output (MPO). They performed 30 and 60-min interval workouts on a cycle ergometer over a 2-week period. Each session started with a 5-min warm-up at 25% MPO followed by 5-min at 50% MPO, 2-min at 25% MPO, 5-min at 75% MPO, 2-min at 25% MPO, 2-min at 100% MPO, 2-min at 25% MPO and 7-min at 50% MPO, which finished the 30-min session. During the first week, 4 sessions consisting of 30-min on Monday, Tuesday, Wednesday and a 60-min (30-min session back to back) on Thursday, were organized. After 3 days off, the second week consisted of 3 consecutive 60-min sessions (Monday to Wednesday) with the last day (Thursday) being of 30-min. HLa and RPE were measured at the end of each stage of the interval training, and HLa/RPE computed for each session. sRPE was obtained after the sessions. Non-linear regression analysis was used to assess the relationship between HLa/RPE and sRPE. RESULTS: A very large negative relationship (r= -0.70, Root-mean-squared error =0.59, p<0.0001) was found (Figure 1). CONCLUSIONS: The negative relationship supports the concept that sRPE is a sensitive tool that, in addition to information about relative exercise intensity, might provide further information on accumulated fatigue. Coaches and exercise scientists without access to HLa measurment may gain insight into accumulated fatigue during periods of increased training by using sRPE.

Contactless Excitation of Piezoelectric Device through Curvilinear shaped Electric Field Generator

Contactless excitation of piezoelectric (PZT) component through focused E-field has been investigated in this work. In the intended technique, E-field is focused to ground electrode from a curvilinear-shaped potential electrode so that maximum E-field can penetrate sufficiently through PZT component which is positioned inbetween the electrodes. Simulation analysis shows that the contactless energization of PZT component is due to electric resonance as well as piezo-electric resonance. The maximum vibration occurs across the PZT components when the E-field generator operating frequency (f0) matches with the mechanical resonance frequency (fm). The max output power across the contactless energized PZT component mainly rely on operating frequency, resonance, position &amp; resistive load. The output power achieved across the contactless excited PZT component by focused E-field generator is higher than the output power achieved across the contactless excited PZT component by capacitor like E- field generator. The max output power of 9.9mW is obtained across PZT component at 1295 kHz resonance frequency (fr) and 19.5 kΩ optimum loads with an input of 50 V and 8 mm electrode separation. By enactment of this excitation methods provide free actuation of PZT component so as to overcome the difficulties associated with the confined motion for different applications.

Mitochondrial adaptations to high intensity interval training in older females and males

Introduction: High intensity interval training (HIIT) has shown to be as effective as moderate intensity endurance training to improve metabolic health. However, the current knowledge on the effect of HIIT in older individuals is limited and it is uncertain whether the adaptations are sex specific. The aim was to investigate effects of HIIT on mitochondrial respiratory capacity and mitochondrial content in older females and males. Methods: Twenty-two older sedentary males (n = 11) and females (n = 11) completed 6 weeks of supervised HIIT 3 days per week. The training consisted of 5 × 1 min cycling (124 ± 3% of max power output at session 2–6 and 135 ± 3% of max power output at session 7–20) interspersed by 1½ min recovery. Before the intervention and 72 h after last training session a muscle biopsy was obtained and mitochondrial respiratory capacity, citrate synthase activity and proteins involved in mitochondria metabolism were assessed. Furthermore, body composition and ⩒O2max were measured. Results: ⩒O2max increased and body fat percentage decreased after HIIT in both sexes (p < 0.05). In addition, CS activity and protein content of MnSOD and complex I-V increased in both sexes. Coupled and uncoupled mitochondrial respiratory capacity increased only in males. Mitochondrial respiratory capacity normalised to CS activity (intrinsic mitochondrial respiratory capacity) did not change following HIIT. Conclusion: HIIT induces favourable adaptions in skeletal muscle in older subjects by increasing mitochondrial content, which may help to maintain muscle oxidative capacity and slow down the process of sarcopenia associated with ageing.

Maximization of the extracted power in resonant electromagnetic vibration harvesters applications employing bridge rectifiers

The capability of a resonant electromagnetic vibration harvester to provide power to a load, in given vibration conditions, is usually quantified by considering the power POPT that can be transferred to the harvester optimal impedance. In this paper it is explained that, in presence of a bridge rectifier between the harvester and the DC load, it is instead necessary to consider the power PSUBOPT, that is the power that can be transferred by the harvester to its optimal resistive load. PSUBOPT≤POPT and represents a more accurate estimate of the upper bound of the average power Ptot that can be actually transferred to the load in case a bridge rectifier is placed between the harvester and the DC load. In particular, in this paper it is shown that a bridge rectifier is able to roughly emulate a resistance and hence Ptot<PSUBOPT≤POPT. By means of a suitable theoretical analysis, it is also demonstrated why and how the power that can be transferred to the load by the harvester strongly depends on the value of the DC voltage V0 at the output of the bridge rectifier. Moreover, a closed form estimate of the optimal value V0* of V0 is also provided. Experimental results are also reported and discussed in order to validate the theoretical findings. In particular, a resonant electromagnetic vibration harvester prototype has been used. The values of its main parameters are: resonance frequency 16.2Hz, max output power 0.25mW (at a vibration amplitude equal to 1g), optimal DC voltage 1.2V, coil resistance=5720.4Ω, coil inductance=0.56H.

Theoretical and experimental study on the application of diffuse-reflection concentrators in PV/T solar system

In order to improve the practicability of PV/T solar system, we proposed the theory and method on the application of diffuse-reflection concentrator in the PV/T solar system and analyzed the concentration characteristics of this proposed application. In addition, we designed experimental prototype of PV/T solar system and conducted test and analysis of the thermal and electrical characteristics of the PV/T solar system with or without a concentrator, respectively. The results showed that for the PV/T solar system with diffuse-reflection concentrator, the amount of incident irradiance was increased by an average of 26% during test period, and the 200-L water in the system was heated to 58 °C, which was 12 °C higher than that of PV/T solar system without diffuse-reflection concentrator; moreover, the max output power was increased by 11%. Therefore, it is a feasible way to improve the practicability of PT/V solar system by integrating a diffuse-reflection concentrator. Copyright © 2016 John Wiley & Sons, Ltd.

Modified output impedance matching solution for load modulation power amplifier performance enhancing

In this study, a modified load-modulated power amplifier (LMPA) structure is presented. Unlike the traditional LMPA (Doherty power amplifier) with quarter-wave line transformers, in this presented LMPA, the two-point matching network for the main amplifier and two-side matching network for the auxiliary amplifier are applied to achieve the back-off efficiency enhancing. The matching networks of the traditional DPAs are analysed and their limiting conditions to achieve optimal performance at back-off and peak power are deduced. A pre-matching is added to transform the load impedance (50 Ω) to complex impedance, then more freedom degrees are introduced to design the two point matching network, which results in the conditions for achieving optimal performance are more relaxed. In this way, the max output power at peak power and the optimal efficiency power at back-off can be achieved for the LMPA simultaneously. To verify the structure, an example LMPA base on GaN devices is designed. The measured max output power is about 43.8 dBm with drain efficiency (DE) of 64.9%. The measured 6 dB back-off DE is 54.9% and 4.5 dB back-off efficiency is 60.1%, which is about 15.2% higher than the class AB power amplifier.

A flexible and implantable piezoelectric generator harvesting energy from the pulsation of ascending aorta: in vitro and in vivo studies

This research is aimed to evaluate the feasibility and efficacy of generating electric power utilizing the pulsating energy of ascending aorta with a flexible and implantable piezoelectric generator (PG) through in vitro and in vivo studies. In the in vitro study, the max output voltage (Vmax), current (Imax) and power (Pmax) of the PG were 10.3V, 400nA and 681nW respectively. The quantity of electric charging by one pulse was about 7–9nC. Factors affecting its output performance were investigated with single variable experiments. We further implanted the PG to wrap around the ascending aorta of a porcine to investigate the output performance in vivo. The Vmax and Imax of the implanted PG were 1.5V and 300nA under the heart rate of 120bpm and the blood pressure of 160/105mmHg. The instantaneous output power was 30nW with a long-lasting duration of 700ms and 77.8% duty ratio. The implanted PG could charge for a 1μF capacitor to 1.0V within 40s.

Single-mode narrow linewidth random fiber laser with enhanced feedback from Rayleigh scattering

The origin of Rayleigh scattering in fiber waveguides is numerically demonstrated, which indicates that the inhomogeneous doping and diameter variations during drawing are the two dominant reasons. And the scattering fiber with a loss as high as 0.54 dB/km is successfully fabricated based on such principles. The overall Rayleigh backscattering intensity of 5 km scattering fiber is 5 dB higher than that of SMF-28 with the same length in telecommunication window. The principle of single-mode random fiber laser is also studied. The emission spectrum is the superposition of a large number of random modes with arbitrary amplitudes and phases, among which only the highest gain modes can lasing through gain competition. In experiment, a single-mode erbium-doped fiber linear laser with a narrow linewidth of 3.5 kHz and a high contrast of 50 dB is achieved by combining with 500 m scattering fiber as the random feedback. The threshold pump current is reduced by 80 mA and the max output power is increased by 3 dBm for the proposed laser compared with those of the laser with 500 m SMF-28 as the feedback. The tunabiltiy of the proposed laser is determined mainly by the fiber Bragg grating.

전자기유도방식의 에너지 하베스팅을 이용한 자가발전 무선 비상호출기 구현 연구

This paper describes the design and implementation of a electromagnetic energy harvesting mechanism and electronic circuit for autonomous emergency call system. This analysis results show the power output of the proposed harvesting mechanism and circuit up to max power output 5V and it can hold up to 65 msec of the power generation and 10msec of the RF transmission. Based on the these testing results, the implementation of autonomous emergency call device without battery power or any external power source is feasible.

Effects of low-level laser irradiation on the pathogenicity of Candida albicans: in vitro and in vivo study.

The purpose of this study was to evaluate the effects of low-level laser irradiation (LLLI) on the in vitro growth characteristics and in vivo pathogenicity of Candida albicans in a murine model in the absence of a photosensitizer. C. albicans is an opportunistic commensal organism that causes a wide variety of diseases in human beings, ranging from superficial infections to life-threatening invasive candidiasis. The incidence of C. albicans infection is increasing, because of the greater frequency of acquired immunodeficiency conditions. A high recurrence rate has been reported for vulvovaginal and oral candidiasis, despite the best available treatments. Therefore, the search for new treatment modalities seems quite rational. Candida culture plates were exposed to common clinical energies of LLLI: 3, 5, 10, and 20 J at 685 nm (BTL Laser 5000, Medicinos Projektai, Czech Republic, Prague, max power output 50 mW) and 3, 5, 10, 30, and 50 J at 830 nm (BTL Laser 5000, Medicinos Projektai, Czech Republic, Prague, max power output 400 mW). Following LLLI with energies >10 J at both 685 and 830 nm wavelengths, statistically significant effects were observed in vitro on the turbidimetric growth kinetics of C. albicans and in vivo on the survival rate of infected mice (p value ≤ 0.05). Therefore, this energy could be considered a threshold for clinical investigation. Translating our data into the clinical setting, it can be proposed that a direct laser-based approach without using a photosensitizing dye can significantly reduce the pathogenicity of Candida albicans. It can also be concluded that laser light at specific wavelengths could be a possible promising novel treatment for superficial and mucocutaneous C. albicans infections.

Effects of cardiovascular fitness and training history on heart rate variability before, during, and after a progressive maximal intensity exercise test (881.2)

Heart rate variability (HRV) is a non‐invasive clinical indicator of cardiovascular health. We sought to examine differences in HRV as a function of exercise choice, frequency, length of regular participation, and aerobic capacity. 83 men (age: 23 ± 4 yr; height: 181 ± 8 cm; body mass: 83 ± 12 kg) with varying exercise preferences participated in the investigation. Heart rate was monitored with a five‐lead electrocardiogram before, during, and after exercise. Each experimental stage was two minutes long: subjects sat, stood, and then cycled in 35 W increments until volitional failure, before sitting in recovery (heart rate max: 184 ± 13 BPM; max power output: 256 ± 54 W; estimated VO2peak 3.16 ± 0.63 [L ● Min ‐1]). Measures of HRV were provided by time domain, frequency, and non‐linear analyses. Principal component analysis was used to distinguish contributory factors for HRV; the reliability of this analysis was confirmed with Chronbach’s Alpha test. Despite the use of a seemingly homogenous sample of college students, our analysis indicated consistent differences in HRV. Specifically, HRV varied with exercise preferences (p蠄0.05), and higher aerobic capacity (determined by the cycle exercise test) was associated with significantly lower HRV (p蠄0.05). We conclude that the unique and specific health benefits of exercise may be reflected in HRV. While further work on long‐term training outcomes is needed, HRV may serve as an indicator of cardiovascular and neuronal adaptations to exercise.

Excessively increased pulmonary artery systolic pressure during exercise in adults with a history of extreme premature birth is unresponsive to sildenafil (1175.8)

Extreme preterm birth results in abnormal alveologenesis and pulmonary vasculogenesis. Abnormal pulmonary vasculature may be unable to accommodate increased cardiac output during exercise, thereby resulting in an abnormally increased pulmonary artery systolic pressure (PASP) and exercise‐induced pulmonary hemorrhage (EIPH) in adult with a history of extreme preterm birth (PRE). We hypothesized that 1) PRE would have increased PASP during exercise thereby causing EIPH and 2) oral sildenafil would reduce PASP thereby preventing EIPH. PRE (n = 2) performed exercise at 80% of max power output to exhaustion on a cycle ergometer 60 mins after 100 mg sildenafil (p.o.) and, on a separate day, without sildenafil. Age and sex matched full term controls (CON; n = 2) exercised at the same workload and for the same time as PRE. PASP was measured via ultrasonography at rest and within the last minute of exercise. Induced sputum samples were collected post‐exercise and analyzed for cellular constituents. PASP was not different at rest between groups. During exercise, PASP was greater in PRE (54 Torr) vs CONT (48 Torr) without drug, and was unchanged in PRE (59 Torr) but decreased in CONT (41 Torr), with sildenafil. There was no evidence of EIPH in either group. These data suggest that excessive PASP during exercise in PRE may be the result of abnormal pulmonary vascular architecture, which cannot be ameliorated by oral sildenafil.Grant Funding Source: Supported by AHA Scientist Development Grant and OHSU Early Clinical Investigator Grant

The Fabrication of Piezoelectric Vibration Energy Harvester Arrays Based on AlN Thin Film

This paper describes the fabrication and measurement results of piezoelectric energy harvester arrays based on aluminum nitride (AlN) as a piezoelectric material. The AlN piezoelectric thin film with crystal orientation (002) and crystal orientation (101) is deposited respectively by pulsed_DC sputtering on the different bottom electrode materials. Based on the AlN thin film, the piezoelectric vibration energy harvester arrays with 5 cantilever beams were developed. Then the load characteristics, frequency characteristics, harvester connected in series and parallel properties of harvester were investigated. In addition, we compare the properties of piezoelectric vibration energy harvester arrays with crystal orientation (101) and (002), where a record max power output of 0.23 μW and 0.38μW are obtained respectively when the value of acceleration was 1 g, while for the latter, the maximum power is 9.13 μW at the acceleration of 5.0g with the optimized resistance of 15 kΩ.

Refractive index graded anti-reflection coating for solar cells based on low cost reclaimed silicon

To meet the demands of the high efficiency and low cost of the photovoltaic industry, it has focused attention on more cost effective silicon cells and cells with a significantly lower energy payback time. In this study, silicon substrates, reclaimed from the integrated circuit industry via polishing and etching treatments, are used after the wet etching process for the surface texturing. An advanced refractive index (RI) graded anti-reflection coating (ARC) is developed based on the stacked depositions of a group of multi silicon nitride nano layers, using an SPTS Plasma Enhanced Chemical Vapor Deposition (PECVD) system. Compared to the cell with single RI ARC, the reclaimed silicon wafers with the novel graded RI ARC have shown a significantly enhanced cell performance. The short circuit current, open circuit voltage, max output power, and fill factor were increased by 7.16%, 4.17%, 30.1% and 15.6%, respectively, based on the low cost reclaimed silicon substrates.