Thermal resistance of building envelopes with heat-conducting elements in summer period

The analysis of the current methods and techniques of solving the problem of heat resistance of building envelopes with heat-conducting elements shows the solution of a onedimensional problem of heat resistance. One of the possible methods for determining the temperature fluctuation amplitude on the inner surface of the building envelopes with heatconducting elements is the modeling of non-stationary temperature conditions in the computer program. However, this solution causes great difficulties, as it transfers the specified calculation from engineering to scientific and cannot be recommended for practical application. The second method of solving this problem is the application of the convergence coefficient, which can be obtained empirically. The selection of the convergence coefficient allows for the influence of the heat-conducting elements on the weighted average surface temperature depending on the envelope configuration.The structural analysis of the building envelopes and their impact on the averaged amplitude of oscillations on the inner surface are conducted. The arrangement of heat-conducting elements at the outer edge is characterized by a negligible influence of the vibration amplitude on the averaged amplitude over the structural surface. The arrangement of heat-conducting elements greatly affects the heat-conducting elements. According to the comparative analysis, the convergence coefficient is preferable in harmonics of the average temperature fluctuations on the inner surface.

Decimetric Type-U Solar Radio Bursts and Associated EUV Phenomena on 2011 February 9

A GOES M1.9 flare took place in active region AR 11153 on 2011 February 9. With a resolution of 200 kHz and a time cadence of 80 ms, the reverse-drifting (RS) type-III bursts, intermittent sequence of type-U bursts, drifting pulsation structure (DPS), and fine structures were observed by the Yunnan Observatories Solar Radio Spectrometer (YNSRS). Combined information revealed by the multiwavelength data indicated that after the DPS was observed by YNSRS, the generation rate of type-U bursts suddenly increased to 5 times what it had been. In this event, the generation rate of type-U bursts may depend on the magnetic-reconnection rate. Our observations are consistent with previous numerical simulation results. After the first plasmoid produced (plasma instability occurred), the magnetic-reconnection rate suddenly increased by 5 to 8 times. Furthermore, after the DPS, the frequency range of the turnover frequency of type-U bursts was obviously broadened to thrice what it was before, which indicates a fluctuation amplitude of the density in the loop top. Our observations also support numerical simulations during the flare-impulsive phase. Turbulence occurs at the top of the flare loop and the plasmoids can trap nonthermal particles, causing density fluctuation at the loop top. The observations are generally consistent with the results of numerical simulations, helping us to better understand the characteristics of the whole physical process of eruption.

Research of Pressure Fluctuation with Experiment and Numerical Simulation for Dredging Pump

In order to reveal the dredge pump flow instability characteristics, the cavitation and pressure fluctuation in experimental study are carried out, the pressure fluctuation frequency domain and time domain characteristics of three different position inside the volute are analyzed. The results showed that, before cavitation, the main frequency at different positions at different flow rates is 1 times the main frequency of the blade. The fluctuation amplitude near the volute tongue and diffusion section is slightly larger than that at other positions. Before cavitation, the fluctuation amplitude at the same position off design flow is slightly higher than that near the design flow. Cavitation has little influence on the main frequency of the pressure fluctuation. After cavitation, the pressure fluctuation amplitude in the low flow point and the position of the volute tongue under each condition has little change, but cavitation aggravates the pressure fluctuation in the other conditions. Besides, the comparison between simulation and experiment results shows the dredge pump performance curve is in good agreement with the simulation curve, and the simulation results of pressure amplitude at different positions are basically consistent with the experiment results, which verifies the reliability of the numerical simulation method.

Pupillary fluctuation amplitude before target presentation reflects short-term vigilance level in Psychomotor Vigilance Tasks

Our daily activities require vigilance. Therefore, it is useful to externally monitor and predict our vigilance level using a straightforward method. It is known that the vigilance level is linked to pupillary fluctuations via Locus Coeruleus and Norepinephrine (LC-NE) system. However, previous methods of estimating long-term vigilance require monitoring pupillary fluctuations at rest over a long period. We developed a method of predicting the short-term vigilance level by monitoring pupillary fluctuation for a shorter period consisting of several seconds. The LC activity also fluctuates at a timescale of seconds. Therefore, we hypothesized that the short-term vigilance level could be estimated using pupillary fluctuations in a short period and quantified their amplitude as the Micro-Pupillary Unrest Index (M-PUI). We found an intra-individual trial-by-trial positive correlation between Reaction Time (RT) reflecting the short-term vigilance level and M-PUI in the period immediately before the target onset in a Psychomotor Vigilance Task (PVT). This relationship was most evident when the fluctuation was smoothed by a Hanning window of approximately 50 to 100 ms (including cases of down-sampled data at 100 and 50 Hz), and M-PUI was calculated in the period up to one or two seconds before the target onset. These results suggest that M-PUI can monitor and predict fluctuating levels of vigilance. M-PUI is also useful for examining pupillary fluctuations in a short period for elucidating the psychophysiological mechanisms of short-term vigilance.

Aggravated stress fluctuation and mechanical size effects of nanoscale lamellar bone pillars

The size effects of mechanical properties influence the microdeformation behaviors and failure mechanisms of hierarchical lamellar bones. Investigations of the continuous deformation behaviors and structure–behavior–property relationships of nanoscale lamellar bones provide essential data for reducing the risk of fracture. Here, five pillars with diameters ranging from 640 to 4971 nm inside a single lamella were fabricated. In situ pillar compressive tests inside a scanning electron microscope directly revealed the diameter-dependent enhanced strength, ductility, and stress fluctuation amplitude. Real-time observations also revealed the segmented deformation and morphological anisotropy of pillars with smaller diameters and the slight elastic recovery of pillars with larger diameters. The critical diameter leading to the brittle-to-ductile transition was confirmed. The “analogous to serrated flow” stress fluctuation behaviors at the nanoscale exhibited a significant size effect, with coincident fluctuation cycles independent of diameter, and each cycle of the fluctuation manifested as a slow stress increase and a rapid stress release. The discontinuous fracture of collagen fibrils, embedded enhancement of hydroxyapatite crystals, and layered dislocation movement on the basis of strain gradient plasticity theory were expected to induce cyclical stress fluctuations with different amplitudes.

Cluster assembly times as a cosmological test

The abundance of galaxy clusters in the low-redshift universe provides an important cosmological test, constraining a product of the initial amplitude of fluctuations and the amount by which they have grown since early times. The degeneracy of the test with respect to these two factors remains a limitation of abundance studies. Clusters will have different mean assembly times, however, depending on the relative importance of initial fluctuation amplitude and subsequent growth. Thus, structural probes of cluster age such as concentration, shape or substructure may provide a new cosmological test that breaks the main degeneracy in number counts. We review analytic predictions for how mean assembly time should depend on cosmological parameters, and test these predictions using cosmological simulations. Given the overall sensitivity expected, we estimate the cosmological parameter constraints that could be derived from the cluster catalogues of forthcoming surveys such as Euclid, the Nancy Grace Roman Space Telescope, eROSITA, or CMB-S4. We show that by considering the structural properties of their cluster samples, such surveys could easily achieve errors of Δσ8 = 0.01 or better.

Water Level Regulation for Eco-social Services Under Climate Change in Erhai Lake Over the Past 68 years in China

Water level plays a crucial role in the function and social services of lakes. Studies on historical changes in water level and its eco-social function can give insights into future water conservation and management. In this study, interannual and seasonal changes in the water level of Erhai Lake were analyzed from 1952 to 2019 to explore water level responses to human activities and climate change. The time series was divided into three distinct periods, i.e., 1952–1971, 1972–2003, and 2004–2019. Results showed that the water level and fluctuation amplitude differed among the different time periods, i.e., 1965.8 and 1.3 m (1952–1971), 1964.4 and 1.9 m (1972–2003), and 1965.2 and 1.2 m (1972–2003), respectively. The construction and operation of a hydroelectric power plant along the outlet river significantly decreased the water level and increased fluctuation amplitude in the 1972–2003 period. Since 2004, due to the implementation of local government water level management laws for Erhai Lake, the water level has remained relatively high, with moderate fluctuation amplitude. In addition, compared to the increase in water level amplitude in response to increased wet season (May–October) precipitation in the 1952–1971 period, response sensitivity increased in the 1972–2003 period, but became non-significant in the 2004–2019 period. In regard to the multi-timescale relationship between water level and precipitation, precipitation decreased by 89 mm in the 2004–2019 period compared with that from 1952 to 1971, and artificial water-level regulation resulted in a time-lag of 2, 3–3.5, and 4 months between water level and precipitation during the 1952–1971, 1972–2003, and 2004–2019 periods, respectively. The eco-social aspects of changes in water level are discussed below, and water level regulation from an ecological perspective is recommended to gain economic returns in the future.

Experimental Study of the Thermal Behavior of a Watercress Planted Roofed Cubic Cell to be Watered with Domestic Wastewater

One of the virtues of watercress is its ability to grow in wastewater. This work aims at experimentally studying the thermal behavior of a watercress planted roofed cubic cell. To do this, the temperatures of various components of the cell and the solar radiation received by this cell were measured in order to compare the watercress roof performance with that of the conventional concrete roof. Then, the influence of the opening applied on the door of the studied cell was analyzed. As results, the fluctuation amplitude of the indoor ambient temperature of the concrete roofed cell is wider than that of the green roofed cell. Moreover, the last opening applied to the facades of the cell was the optimum area that the ambient temperature indoor was more attenuated. The LAI’s crop was worth 1.2. In addition, the low value of the canopy apparent thermal conductivity revealed that this layer plays a role of thermal insulation. The rooftop greening allows energy savings of about 85% compared to the consumed energy with conventional roofing. An extension of this work could be the energy performance analysis of a system using renewable energy for pumping domestic wastewater produced in or around green roofed housing.

Preliminary simulation analysis of the temperature fluctuation effect on Taiji-1 Laser interferometer

Space-borne gravitational wave detection imposes a demanding requirement on the sensitivity of the laser interferometer. Among all disturbances that affect the measurement accuracy of the laser interferometer, temperature fluctuations contribute significantly. In this paper, the structure model and the interference path design of Taiji-1 laser interferometer have been used to conduct a preliminary simulation analysis of the temperature fluctuation noise through the finite element method. The temperature, the displacement and the optical path difference fluctuations have been obtained and theoretically analyzed. The preliminary simulation results are consistent with the theoretical analysis, which shows that the thermal–structural–optical simulation scheme adopted in this paper is reasonable. With the preliminary simulation results and the actual temperature control of Taiji-1 laser interferometer, we estimate that in Taiji-1 laser interferometer system, the temperature fluctuation is below the order of mK, the node displacement is within [Formula: see text][Formula: see text]pm, and the interference arm length difference fluctuation amplitude of the laser interferometer is also within [Formula: see text][Formula: see text]pm.

Hubble parameter and related formulas for a Weyl scaling invariant dark energy action

We extend our previous analysis of a model for “dark energy” based on a Weyl scaling invariant dark energy action. We reexpress all prior results in terms of proper time, using the fluctuation amplitude [Formula: see text] without approximation, and derive a compact formula for the squared effective Hubble parameter. This formula involves effective dark energy and matter densities that differ from their expressions in the standard [Formula: see text] cosmology. We also give new analytic results for the function [Formula: see text] and discuss their implications.