Output Intensity Research Articles

Orthogonal dispersion modeling of double-stage VIPA spectrometer in SBS system

Brillouin microscopy enables the assessment of the mechanical properties of biological tissues by mapping the Brillouin shift in three-dimensional (3D), all-optical, label-free, non-contact, and subcellular resolution. The virtually imaged phased array (VIPA) etalon is widely utilized for measuring Brillouin spectra owing to its superior light throughput, large angular dispersion, and rapid signal acquisition capabilities. The VIPA-based spectrometer plays a significant role in Brillouin microscopy, but it is highly sensitive to factors such as the tilt angle, beam radius, lens focal length, and so on. Here, we propose an orthogonal dispersion model based on paraxial wave theory. This model is employed to explore the output intensity distribution and dispersion characteristics of a double-stage VIPA spectrometer. To validate the proposed model, we develop a stimulated Brillouin scattering (SBS) system by leveraging the optimal spectrometer parameters to measure the Brillouin frequency shift in pure water. We demonstrate the capabilities of this model in mitigating spectral dispersion and enhancing spectral measurement accuracy by optimizing the spectrometer's system parameters. This work is pivotal for the future deployment of the double-stage VIPA spectrometer in SBS-based microscopy applications.

Depth of Cure of Resin-Based Composites Irradiated With Three Types of Light-Curing Units at Different Output Intensities

Depth of Cure of Resin-Based Composites Irradiated With Three Types of Light-Curing Units at Different Output Intensities

An eco-efficient European metal industry transition towards Circular Economy

The European metal industry can minimize carbon and energy intensity through Circular Economy (CE) solutions in order to achieve the Agendas’ 2030; 2050 targets. This paper evaluates the eco-efficiency in 21 European countries using hybrid window data envelopment analysis (WDEA) across two scenarios. The study compares short- and a meso-term policies by choosing different window widths. Inputs include gross fixed capital formation (GFCF), labor force, and energy intensity value added, with value added as desirable output and carbon intensity value added as undesirable output. Results show that the meso-term policy yields an average eco-efficiency of 47%, while the short-term policy achieves 55%, suggesting that short-term strategies are more effective for the metal industry in reaching the Net-Zero goals. Geographically, Western and Northern Europe exhibit better eco-efficiency than Eastern and Southern Europe. In essence, the European metal industry can reach a Net-Zero status through deep CE transformations in energy and carbon intensity via cleaner production.

Training for Elite Team-Pursuit Track Cyclists-Part I: A Profile of General Training Characteristics.

To profile the training characteristics of an elite team pursuit cycling squad and assess variations in training intensity and load accumulation across the 36-week period prior to a world-record performance at the 2018 Commonwealth Games. Training data of 5 male track endurance cyclists (mean [SD]; age 21.9 [3.52]y; 4.4 [0.16]W·kg-1 at anaerobic threshold; 6.2 [0.28]W·kg-1 maximal oxygen uptake 68.7 [2.99]mL kg·min-1) were analyzed with weekly total training volume and heart rate, power output, and torque intensity distributions calculated with reference to their 3:49.804min:s.ms performance requirements for a 4-km team pursuit. Athletes completed 543 (37)h-1 of training across 436 (16) sessions. On-bike activities accounted for 69.9% of all training sessions, with participants cycling 11,246 (1139)km-1 in the training period of interest, whereas 12.7% of sessions involved gym/strength training. A pyramidal intensity distribution was evident with over 65% and 70% of training, respectively, performed at low-intensity zone heart rate and power output, whereas 5.3% and 7.7% of training was performed above anaerobic threshold. The athletes accumulated 4.4% of total training volume at, or above, their world-record team pursuit lead position torque (55N·m). These data provide updated and novel insight to the power and torque demands and load accumulation contributing to world-record team pursuit performance. Although the observed pyramidal intensity distribution is common in endurance sports, the lack of shift toward a polarized intensity distribution during taper and competition peaking differs from previous research.

Training for Elite Team-Pursuit Track Cyclists-Part II: A Comparison of Preparation Phases in Consecutive World-Record-Breaking Seasons.

To compare the training characteristics of an elite team pursuit cycling squad in the 3-month preparation phases prior to 2 successive world-record (WR) performances. Training data of 5 male track endurance cyclists (mean [SD]; age 23.4 [3.46]y; body mass 80.2 [2.74]kg; 4.5 [0.17]W·kg-1 at LT2; maximal aerobic power6.2 [0.27]W·kg-1; maximal oxygen uptake 65.9 [2.89]mL·kg-1·min-1) were analyzed with weekly total training volume by training type and heart rate, power output, and torque intensity distributions calculated with reference to the respective WRs' performance requirements. Athletes completed 805 (82.81) and 725 (68.40)min·wk-1 of training, respectively, in each season. In the second season, there was a 32% increase in total track volume, although track sessions were shorter (ie,greater frequency) in the second season. A pyramidal intensity distribution was consistent across both seasons, with 81% of training, on average, performed below LT1 power output each week, whereas 6% of training was performed above LT2. Athletes accumulated greater volume above WR team pursuit lead power (2.4% vs 0.9%) and torque (6.2% vs 3.2%) in 2019. In one athlete, mean single-leg-press peak rate of force development was 71% and 46% higher at mid- and late-phases, respectively, during the preparation period. These findings provide novel insights into the common and contrasting methods contributing to successive WR team pursuit performances. Greater accumulation of volume above race-specific power and torque (eg,team pursuit lead), as well as improved neuromuscular force-generating capacities, may be worthy of investigation for implementation in training programs.

Signal-enhanced electrochemical sensor employing MWCNTs/CMK-3/AuNPs and Au@Pd core-shell structure for sensitive determinationof AFB1 in complex matrix.

A sandwich electrochemical sensor was fabricated based on multi-walled carbon nanotubes/ordered mesoporous carbon/AuNP (MWCNTs/CMK-3/AuNP) nanocomposites and porous core-shell nanoparticles Au@PdNPs to achieve rapid and sensitive detection of AFB1 in complex matrices. MWCNTs/CMK-3/AuNP nanocomposite, which was prepared by self-assembly method, served as a substrate material to increase the aptamer loading and improve the conductivity and electrocatalytic activity of the electrode for the first signal amplification. Then, Au@PdNPs, which were synthesized by one-pot aqueous phase method, were applied as nanocarriers loaded with plenty of capture probe antibody (Ab) and signal molecule toluidine blue (Tb) to form the Au@PdNPs-Ab-Tb bioconjugates for secondary signal amplification. The sensing system could still significantly improve the signal output intensity even in the presence of ultra-low concentration target compounddue to the dual signal amplification of MWCNTs/CMK-3/AuNP nanocomposites and Au@PdNPs-Ab-Tb. The method exhibited high selectivity, low detection limit (9.13fg/mL), and strong stability to differentiate AFB1 from other mycotoxins. Furthermore, the sensor has been successfully applied to the quantitative determination of AFB1 in corn, malt, and six herbs, which has potential applications in food safety, quality control, and environmental monitoring.

Uncovering socio-economic driving forces of volatile organic compounds emissions in the Beijing-Tianjin-Hebei region of China

The Beijing-Tianjin-Hebei (BTH) region is an important urban agglomeration in northern China, which has experienced rapid economic growth and heavy air pollution such as volatile organic compounds (VOCs) emissions. It is therefore urgent to uncover the socio-economic driving forces of VOCs emissions so that the BTH region can move toward sustainable development. This study aims to fill this research gap by measuring the contributions of different socio-economic factors to VOCs emissions in the BTH region during 2008–2017 by using the generalized Divisia index method (GDIM). Our results show that energy consumption scale and economic scale are the two largest contributors to the increase of VOCs emissions, while emission intensity of output and emission intensity of energy are the two dominant drivers for preventing the increase of VOCs emissions in the BTH region. Other factors, such as population scale, per capita emission, per capita GDP, and energy intensity, have marginal effects on VOCs emissions. These findings provide valuable insights to those policy makers in the BTH region to prepare effective measures to mitigate their VOCs pollution by considering regional disparity.

Customizable beam splitting in planar adiabatic acoustic couplers composed of cylindrical scatterers.

In this work, five-waveguide (five-WG) acoustic couplers with planar configurations are designed based on quantumlike adiabatic transfer, through which the incident waves can efficiently transfer from the middle WG to the other two WGs with a customized intensity ratio. The five WGs are connected by space-varying cylindrical scatterers, and the coupling between two adjacent WGs is determined by two Gaussian pulses with a certain delay. Since the evolution process of acoustic waves can adiabatically follow the dark state, the coupler could have a broadband and stable performance. Moreover, it is easy to change the ratio of the beam splitting by utilizing different peak values of the coupling between the middle three WGs. The agreements between analytical, numerical, and experimental results confirm the feasibility of the design, providing an effective solution for high-performance acoustic beam splitters with customizable output intensities.

Reaching the precision limit with tensor-based wavefront shaping

Perturbations in complex media, due to their own dynamical evolution or to external effects, are often seen as detrimental. Therefore, a common strategy, especially for telecommunication and imaging applications, is to limit the sensitivity to those perturbations in order to avoid them. Here, instead, we consider enhancing the interaction between light and perturbations to produce the largest change in the output intensity distribution. Our work hinges on the use of tensor-based techniques, presently at the forefront of machine learning explorations, to study intensity-based measurements where its quadratic relationship to the field prevents the use of standard matrix methods. With this tensor-based framework, we can identify the maximum-information intensity channel which maximizes the change in its output intensity distribution and the Fisher information encoded in it about a given perturbation. We further demonstrate experimentally its superiority for robust and precise sensing applications. Additionally, we derive the appropriate strategy to reach the precision limit for intensity-based measurements, leading to an increase in Fisher information by more than four orders of magnitude compared to the mean for random wavefronts when measured with the pixels of a camera.

Coupled analysis of arable land input intensity and output intensity based on sliding windows

Sustainable intensification (SI) of agriculture can produce more food to meet the demand of a growing population while considering ecosystem health. The current SI estimation framework ignores the complex coupling between input and output intensity of arable land. A method for coupled analysis of arable land input intensity and output intensity based on sliding windows is proposed. By calculating the correlation coefficient and partial correlation coefficient between input intensity and output intensity in different value ranges as the order parameter, the phase transition and the influence process of input intensity on output intensity can be explained. Meanwhile, a python-based framework is developed.An application of the method was made to reveal the interaction process between annual provincial input intensity and output intensity in mainland China. Researchers in many fields may benefit from the method by obtaining a fast way to analysis the coupling relationship between driving and dependent variables in complex systems.•New method for SI estimation is presented.•The order parameter of the coupling relationship between input and output intensity is calculated based on sliding windows.•Analysis of coupling relationships between driving and dependent variables in complex systems.

Determinants of urban agriculture market participation decision and intensity in eastern Ethiopia

Small-scale urban farmers' active involvement in the urban agriculture (UA) output market is one strategy to ease an urban food shortage while sustaining their livelihoods and income. Enhancing market participation and intensity requires identifying the factors that affect UA market participation. Thus, the study aimed to determine the factors influencing UA market participation decisions and intensity in Eastern Ethiopia. Using a semi-structured questionnaire, the study utilized primary data collected from 270 randomly selected urban farmers. The Double Hurdle (DH) Model was used to determine the factors influencing urban farmers' participation and intensity in the UA output market. According to the first stage DH Model results, age, education, occupation, family size, farming experience, UA-related training, dependency ratio, and market information, all had a significant impact on the decision to participate in the UA output market. The second stage DH Model of Truncated regression indicated that the intensity of UA output market participation decision was significantly affected by the education, land size, UA-related training, and market information are all important factors determine the intensity of UA output market participation. Improving the ability to use the land for UA purposes, awareness creation through short-term training, and improving information access are important recommendations to enhance UA output market participation and intensity of participation.

Free-space laser emission from Nd:YAG elliptical microdisks.

The utilization of deformed microcavities, such as elliptical microdisks, has been widely acknowledged as an effective solution for achieving free-space emission in microcavity lasers. However, the deformations introduced in the microcavity structure tend to decrease the quality factor (Q factor), resulting in weakened output intensity. To address this issue, one potential approach is to employ highly efficient laser gain media that can compensate for the negative impact of the structure on the output intensity. In this study, we employed the exceptional laser crystal material Nd:YAG as the laser gain medium and successfully fabricated an elliptical microdisk laser with a major semiaxis of 15 µm and an eccentricity ratio of 0.15. By utilizing an 808 nm laser for pumping, we were able to achieve free-space laser emission with a slope efficiency of 1.7% and a remarkable maximum output power of 58 µW. This work contributes toward the advancement of the application of deformation microcavity lasers.

High performance of straight and U-shaped probe microfiber sensors for sucrose solution detection applications

A low cost, highly sensitive sensor with easy fabrication has been successfully developed to detect variations in the concentration of sucrose solutions using a microfiber probe sensor. The microfiber probe was fabricated using a flame brushing mixture of butane and oxygen with single-mode optical fiber material and pulled on both sides to achieve a size of 16.48 µm. These microfiber probes were characterized into two sensor probe shapes: straight and u-shaped, to measure variations in the sucrose solution concentration. The results for both probe shapes showed a decrease in peak output intensity and a shift in peak wavelength as the sucrose concentration increased from 0.5% to 3%. The straight shape exhibited a sensitivity of 0.241 dBm/% with a slope linearity of 99.5% and a resolution of 0.0415%, while the U-shape had a sensitivity of 2.692 dBm/% with a slope linearity of 90.6% and a resolution of 0.0030%. The measurement spectra results indicated significant differences in u-shape at each concentration. In conclusion, both microfiber sensor probe shapes exhibited excellent performance and are suitable for use as chemical sensors to measure variations in solutions.

Triplet-Triplet Annihilation Upconverting Liposomes: Mechanistic Insights into the Role of Membranes in Two-Dimensional TTA-UC.

Triplet-triplet annihilation upconversion (TTA-UC) implemented in nanoparticle assemblies is of emerging interest in biomedical applications, including in drug delivery and imaging. As it is a bimolecular process, ensuring sufficient mobility of the sensitizer and annihilator to facilitate effective collision in the nanoparticle is key. Liposomes can provide the benefits of two-dimensional confinement and condensed concentration of the sensitizer and annihilator along with superior fluidity compared to other nanoparticle assemblies. They are also biocompatible and widely applied across drug delivery modalities. However, there are relatively few liposomal TTA-UC systems reported to date, so systematic studies of the influence of the liposomal environment on TTA-UC are currently lacking. Here, we report the first example of a BODIPY-based sensitizer TTA-UC system within liposomes and use this system to study TTA-UC generation and compare the relative intensity of the anti-Stokes signal for this system as a function of liposome composition and membrane fluidity. We report for the first time on time-resolved spectroscopic studies of TTA-UC in membranes. Nanosecond transient absorption data reveal the BODIPY-perylene dyad sensitizer has a long triplet lifetime in liposome with contributions from three triplet excited states, whose lifetimes are reduced upon coinclusion of the annihilator due to triplet-triplet energy transfer, to a greater extent than in solution. This indicates triplet energy transfer between the sensitizer and the annihilator is enhanced in the membrane system. Molecular dynamics simulations of the sensitizer and annihilator TTA collision complex are modeled in the membrane and confirm the co-orientation of the pair within the membrane structure and that the persistence time of the bound complex exceeds the TTA kinetics. Modeling also reliably predicted the diffusion coefficient for the sensitizer which matches closely with the experimental values from fluorescence correlation spectroscopy. The relative intensity of the TTA-UC output across nine liposomal systems of different lipid compositions was explored to examine the influence of membrane viscosity on upconversion (UC). UC showed the highest relative intensity for the most fluidic membranes and the weakest intensity for highly viscous membrane compositions, including a phase separation membrane. Overall, our study reveals that the co-orientation of the UC pair within the membrane is crucial for effective TTA-UC within a biomembrane and that the intensity of the TTA-UC output can be tuned in liposomal nanoparticles by modifying the phase and fluidity of the liposome. These new insights will aid in the design of liposomal TTA-UC systems for biomedical applications.

Synergistic efficacy of ultrasound and ammonium persulfate in inactivating Escherichia coli O157:H7 in buffered peptone water and orange juice

This study investigated the synergistic effects of ammonium persulfate (PS) and ultrasound (US) on the inactivation of Escherichia coli O157:H7 in buffered peptone water (BPW) and orange juice products. A comprehensive assessment of PS concentrations ranging from 1 to 300 mM, considering not only the statistical significance but also the reliability and stability of the experimental outcomes, showed that 150 mM was the optimal PS concentration for the inactivation of E. coli O157:H7. Additionally, US output intensities varying from 30 % to 60 % of the maximum US intensity were evaluated, and 50 % US amplitude was found to be the optimal US condition. A 50 % amplitude setting on the sonicator corresponds to half of its maximum displacement, approximately 60 μm, based on a maximum amplitude of 120 μm. The inactivation level of E. coli O157:H7 was significantly enhanced by the combined treatment of PS and US, compared to each treatment of PS and US alone. In the BPW, a 10-min treatment with the combination of PS and US resulted in a significant synergistic inactivation, achieving up to a log reduction of 3.86 log CFU/mL. Similarly, in orange juice products, a 5-min treatment with the combination of PS and US yielded a significant synergistic inactivation, with a reduction reaching 5.90 log CFU/mL. Although the treatment caused a significant color change in the sample, the visual differences between the treated and non-treated groups were not pronounced. Furthermore, the combined treatment in orange juice demonstrated significantly enhanced antimicrobial efficacy relative to BPW. Despite identical 5-min treatment periods, the application in orange juice resulted in a substantially higher log reduction of E. coli O157:H7, achieving 7.16 log CFU/mL at a reduced PS concentration of 30 mM, whereas the same treatment in BPW yielded only a 2.89 log CFU/mL reduction at a PS concentration of 150 mM, thereby highlighting its significantly superior antimicrobial performance in orange juice. The mechanism underlying microbial inactivation, induced by the combined treatment of PS and US, was identified as significant cell membrane damage. This damage is mediated by sulfate radicals, generated through the sono-activation of persulfate. In addition, the low pH of orange juice, measured at 3.7, is likely to have further deteriorated the E. coli O157:H7 cells compared to BPW (pH 7.2), by disrupting their cell membranes, proton gradients, and energy metabolism. These findings underscore the effectiveness of PS and US integration as a promising approach for non-thermal pasteurization in the food industry. Further research is needed to optimize treatment parameters and fully explore the practical application of this technique in large-scale food processing operations. Sensory evaluation and nutritional assessment are also necessary to address the limitations of PS.

Accuracy of linear transformations performed on a nonideal Mach–Zehnder interferometer

We consider a mathematical model of a planar Mach–Zehnder interferometer with nonideal beam splitters. For this model, we obtain two fidelity estimates of the matrix–vector multiplication in the form of dependences of the multiplication error on the beam splitting error in directional couplers. The first estimate is obtained as a measure of the difference between the transfer matrices implemented by interferometers and is presented in the form of the norm of the difference between two unitary matrices corresponding to ideal and non-ideal interferometers. The second estimate is obtained as a measure of the difference in output intensities. It is shown that in the latter case the fidelity depends both on the beam splitter error and on the parameters of the input signals. We verified the second estimate using computer simulations of MZI in COMSOL Multiphysics.

DETERMINANTS OF PHYSIOLOGICAL RESPONSE TO EXERTIONAL HEAT STRESS IN HUMANS

INTRODUCTION AND AIMS Previous field studies of exercise undertaken in hot conditions reported dissociation between heat-related symptoms and body core temperature (Tc) elevation. This prompted us to examine physiological mechanisms underpinning responses to exertional heat exposure in a controlled laboratory experiment. METHODS Thirty-eight apparently healthy participants had body composition (DEXA) and fitness (V̇O2peak) measured in a preliminary visit. Tc, heart rate (HR), exercise intensity (V̇O2) and echocardiographic measures of end-diastolic volume (EDV), stroke volume (SV) and cardiac output (Q̇) were measured at rest and at 30-minute intervals throughout a two-hour walk (5km/h and 2% gradient) in a climate-controlled chamber (40⸰C and 50% relative-humidity). RESULTS Twenty-seven participants completed the experiment (Completers; Com), 7 were stopped due to Tc exceeding 39⸰C (Hyperthermics; Hyp). Four participants did not complete the protocol due to adverse symptoms and were excluded from this analysis. Hyp had significantly greater Tc at 60-minutes (38.6±0.5⸰C vs. 38.0±0.3⸰C; P=<0.001) and 90-minutes (39.0±0.3⸰C vs. 38.3±0.3⸰C; P=<0.001) than Com. Baseline V̇O2peak (ml.kg-1.min-1) did not differ between Hyp and Com (P=0.248). Whilst body weight and lean body mass did not significantly differ between Hyp and Com, visceral adipose tissue (VAT) volume (463.2±194.3cm3 vs. 259.9±284.4cm3 P=0.014) and mass (437.0±183.1g vs. 245.2±268.2g P=0.013) were significantly greater in Hyp vs Com. In Hyp, HR change from baseline was greater at 60-minutes (Δ57±15bpm vs. Δ36±18bpm; P=0.01) and 90-minutes (Δ63±20bpm vs. Δ42±19bpm; P=0.017), whilst change in EDV (Δ-22.7±11.4ml vs. Δ-6.92±11.2ml; P=0.016) and SV (Δ-19.4±6.1ml vs. Δ-0.7±7.5ml; P=<0.001) were significantly reduced in Hyp compared to Com. CONCLUSION During walking in the heat, subjects who became hyperthermic had significantly higher baseline visceral fat mass and early signs of exaggerated haemodynamic burden during exertional heat exposure. This study has implications for the identification of appropriate variables for establishing safe work limits during heat exposure in military and work-related contexts.

Polarization-independent edge detection based on the spin–orbit interaction of light

In previous edge detection schemes based on the spin-orbit interaction of light, the direction and intensity of the edge-enhanced images are influenced by the incident polarization state. In this study, we develop an edge detection strategy that is insensitive to changes in both the incident polarization and the incident angle. The output intensity and transfer function remain entirely impervious to changes in incident polarization, being explicitly formulated as functions of the incident angle, specifically in terms of cot2⁡θ i and cot⁡θ i , respectively. This behavior is attributed to the opposing nature of the polarization components E~ r H−H and E~ r V−V in the x-direction after undergoing mapping through the Glan polarizer, while the sum of polarization components E~ r H−V and E~ r V−H in the y-direction can be simplified to terms independent of incident polarization. Furthermore, we propose a metasurface design to achieve the required optical properties in order to realize the derived edge detection scheme.

Single-shot measurement of photonic topological invariant

Topological design enables robustness to be engineered into a system. However, a general challenge remains to experimentally characterize topological properties. In this work, we demonstrate a technique for directly observing a winding-number invariant using a single measurement. By propagating light with a sufficiently broad spectrum along a topological photonic crystal fiber, we calculate the winding number invariant from the output intensity pattern. We quantify the capabilities of this single-shot method, which works even for surprisingly narrow and asymmetric spectral distributions. We demonstrate our approach using topological fiber, but our method is generalizable to other platforms. Our method is experimentally straightforward: we use only a broadband input excitation and a single output to measure the topological invariant. Published by the American Physical Society 2024

Feedback enhanced phonon lasing of a microwave frequency resonator

The amplitude of self-oscillating mechanical resonators in cavity optomechanical systems is typically limited by nonlinearities arising from the cavity’s finite optical bandwidth. We propose and demonstrate a feedback technique for increasing this limit. By modulating the cavity input field with a signal derived from its output intensity, we increase the amplitude of a self-oscillating GHz frequency mechanical resonator by 22% (an increase in coherent phonon number of 50%), limited only by the achievable optomechanical cooperativity of the system. This technique will advance applications dependent on high dynamic mechanical stress, such as coherent spin-phonon coupling, as well as the implementation of sensors based on self-oscillating resonators.