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This paper modeled the tension fluctuation during automated fiber placement (AFP), which depicted the tension variations under different operating conditions. The stability and validity of the model were demonstrated using Bode plots and experiments, respectively. According to the model, the tension fluctuations of AFP at different stages were obtained. Additionally, the passive dancer parameters with the better system performance were determined using the evaluation methodology presented in this paper. Moreover, it was discovered that the damping coefficient affects the tension variation more significantly than the elasticity coefficient. Finally, the placement experiments showed that the determined passive dancer parameters improved the laying quality significantly. [ABSTRACT FROM AUTHOR]

In this paper, the fracture durability of composite–titanium adhesively bonded structures exposed to seawater environment was studied experimentally and numerically. The specimens were immersed in artificial seawater at 45°C for different exposure times. The results show that the tensile strength of the specimen aging for 130 days degraded by nearly 55.6%, and the degradation of the mechanical properties of adhesive was not only affected by the moisture but also showed a certain relationship with aging time. Under the condition of saturated moisture, the tensile strength of the specimen still decreased with the increase of aging time. The simulated moisture results of the aging fracture specimen indicate that the moisture of the boundary region of the adhesive layer was mainly absorbed from the adhesive itself, while the moisture of the central region was dependent on the moisture absorption of the composite adherend. Moreover, the moisture absorption of the pre‐crack tip adhesive resulted in different load responses and fracture modes of the aging fracture specimens. Consequently, the fracture toughness of the DCB and ENF specimens aging for 180 days degraded by nearly 66.4% and 33.0%, respectively. Highlights: Degradation of adhesive was also related to aging time apart from moisture.Boundary and central region severally absorb water from adhesive and CFRP.Moisture of the pre‐crack tip adhesive affected load responses and fracture modes.After 180 days, fracture toughness of modes I and II degraded by 66.4% and 33.0%. [ABSTRACT FROM AUTHOR]

The investigation on fracture test methods for dissimilar materials adhesively bonded structures is urgent. In this study, three mode II fracture test methods for composite‐titanium adhesively bonded structures are experimentally and numerically studied. A manual inverse fitting method is adopted to obtain accurate cohesive models, and sensitivity evaluation of test methods is comprehensively conducted. The results show that GII of the experimental end‐notched flexure (ENF) test is nearly 20% greater than end‐loaded split (ELS). The effect of friction can be ignored, while all methods are highly dependent on the adherend's thickness, especially the maximum deviation of ELS that is 23.74%. In addition, the condition that the adherend with smaller flexural stiffness places outside the bending direction should be avoided to achieve mode II dominant possibly. In summary, the ENF test method with span length of 100 mm and small adherend's thickness is recommended for the mode II fracture test of the dissimilar materials adhesively bonded structures. Highlights: End‐notched flexure (ENF), four‐point bending end‐notched flexure (4ENF), and end‐loaded split (ELS) test methods for carbon‐fiber‐reinforced plastics (CFRP)‐titanium bonded structures are studied.The GII obtained from the ENF test is relatively greater than 4ENF and ELS.All methods are highly dependent on adherend's thickness.Adherend with low flexural stiffness should not place outside bending direction.ENF test with span length of 100 mm and small adherend's thickness is recommended. [ABSTRACT FROM AUTHOR]

Nowadays, fracture characterization of dissimilar materials adhesively bonded structures still generally refers to standards for fiber‐reinforced plastic composites. Moreover, the calculation methods of fracture energy release rate specified in these standards often lead to great deviation due to the differences in material properties and geometry. In this paper, dissimilar materials corrected beam theory with effective crack length (DM‐CBTE) method for calculation of mode II fracture energy release rate of dissimilar materials adhesively bonded structures was proposed. The differences in material properties and geometry as well as the effect of clamp were all considered. The experimental and J‐integral numerical analysis results showed that the maximum deviation of the GIIC calculated by the methods recommended in standard from the J‐integral result is 28% while that by the DM‐CBTE method is only 5%, which proved good feasibility of the DM‐CBTE method for evaluation of mode II fracture performance of dissimilar materials adhesively bonded structures. Highlights: DM‐CBTE method for GII of dissimilar materials adhesively bonded samples was proposed.The differences in material, geometry, and clamp correction were all considered.Good feasibility of the DM‐CBTE method for evaluation of GII was validated. [ABSTRACT FROM AUTHOR]

In lost foam casting (LFC), the distribution of polymer beads during the bead filling process is not uniform, and the collision between polymer beads determines the distribution of two-phase flow of gas and solid. The interaction between the gas and solid phases reveals as coupling effect of the force that gas exerts on particles or vice versa, or that among particles. The gas-solid flow in filling process is nonlinearity, which makes the coupling effect an essential point to carry out a simulation properly. Therefore, information of each particle’s motion is important for acquiring the law of filling process. In bead filling process, compressed air is pressed into mold cavity, and discharged from gas vent, creating a pressure difference between outer and inner space near the gas vent. This pressure difference directly changes the spatial distribution and motion trace of gas and solid phases. In this paper, Discrete Element Method (DEM) and Computational Fluid Dynamics (CFD) are employed to simulate the fluid dynamic character based on Newton’s Third Law of Motion. The simulation results of some casting products such as pressure plate and valve handle are compared with the result obtained from practical experiment in order to test the feasibility of DEM. The comparison shows that this DEM method can be a very promising tool in the mould filling simulation of beads’ movement.

In lost foam casting (LFC) the foam pattern is the key criterion, and the filling process is crucial to ensure the high quality of the foam pattern. Filling which lacks uniformity and denseness will cause various defects and affect the surface quality of the casting. The infl uential factors of the fi lling process are realized in this research. Optimization of the fi lling process, enhancement of effi ciency, decrease of waste, etc., are obtained by the numerical simulation of the fi lling process using a computer.The equations governing the dense gas-solid two-phase flow are established, and the physical significance of each equation is discussed. The Euler/Lagrange numerical model is used to simulate the fluid dynamic characteristics of the dense two-phase fl ow during the mould fi lling process in lost foam casting. The experiments and numerical results showed that this method can be a very promising tool in the mould fi lling simulation of beads' movement.

For automated fiber placement onto molds with complex surfaces, uneven compaction pressure distribution limits tows number in a single sequence and affects layup quality. Compaction roller has a direct influence on the pressure distribution, but the relationship between the two has not been widely explored. In this paper, the segmented compaction roller is used, and a theoretical model of compaction pressure distribution for layup onto general surfaces is established by analyzing the contact between the roller and prepreg layers, followed by experimental validation. Based on the model, single-point pressure uniformity and whole-path pressure uniformity are proposed to quantitatively evaluate the pressure distribution. Furthermore, pressure distribution and pressure uniformity of segmented roller and common roller are compared, as well as the influence of the two pressure distribution on layup quality. The results show that the established model can predict pressure distribution and provide a basis for analyzing layup defects, and segmented rollers apply evener compaction pressure and help to improve layup quality. [ABSTRACT FROM AUTHOR]

Automated fiber placement (AFP) combining with the autoclave curing process is the main manufacturing method for large-scale rotary composite parts. During the forming process, the mandrel plays an important role that affects the forming quality of the part directly. In this study, design and analysis of the mandrel structure for a composite S-shaped inlet are carried out. The preforming process of the rotary composite part using the AFP technique is introduced first. Then, design principles of the shaft are presented and applied to the shaft design for the mandrel of the S-shaped inlet, which then is transformed into an optimization problem. The internal penalty function method is adopted to solve this optimization problem in order to obtain the optimal axis position and axle diameter. Moreover, detailed structure design of the mandrel is proposed which takes the demolding into consideration, and the wall thickness is designed considering the total weight and the stiffness. The static analysis and modal analysis are also carried out by the finite element method to verify the feasibility of the proposed mandrel structure. [ABSTRACT FROM AUTHOR]

Rapid progress of solar photovoltaic (PV) technology has caused growing interest in understanding interactions between large scale PV plants and near-surface atmosphere. However few attempts have been made to quantify the impact of PV modules on surface radiative forcing and energy partitioning process. Here, this issue is explored experimentally and analytically in the two adjacent sites located at the PV plant and the natural barren field respectively in Wujiaqu in Xinjiang of China. The results showed that the physical effect of PV panels is not symmetrical in the whole day. During the daytime, compared with the reference site, net shortwave radiative forcing increases 8%, a warming effect on the integrated underlying surface (0.1 K) and a cooling effect (∼-2.6 K) on the ground surface were found in the PV plant. 9.2% of the net radiation (NR) was converted into electric energy (PE), sensible heat flux (H) increased by 30.6% hence resulted in the convection heating effects of 0.64 K and 0.32 K on the near-surface air temperature at the height of 2 m and 10 m respectively, while latent heat flux (LE) and ground surface heat flux (GS) decreased by 49% and 3% respectively related to the reference site. At night, PV panels produce a cooling effect of −0.2 K and −2.3 K on the ground and integrated underlying surface respectively, and less GS is released in the PV plant which contribute to the cooling effects of −0.24 K and −0.08 K on the air temperature at the height of 2 m and 10 m respectively related to the reference site. In the whole day, in the PV plant, H increased by 27.6%, LE and GS decreased by 47.4% and 6.7% respectively, air temperature increased by 0.16 K and 0.1 K at 2 m and 10 m respectively. • The physical effect of PV modules is not symmetrical in the whole day. • Net shortwave radiative forcing induced by PV modules increases 7.2%. • Sensible heat increases 34.4% and latent heat decreased 20.9% in PV plant related to reference site. • Ground surface heat decreases 7.4%. • The reasons of physical effect of PV modules were explained. [ABSTRACT FROM AUTHOR]

Unfrozen water content significantly affects the thermal‐hydro‐mechanical characteristics of frozen soil. Currently, theoretical explanations for the presence of unfrozen water include capillary action, surface effects, adsorption forces, and the electrical double layer. However, the relationships between unfrozen water and these actions are not well explained, except for capillary forces. In addition, although frost heave experiments indicate that the electrical double‐layer solution on a clay particle contains the main portion of unfrozen water, the electrical double‐layer theory which produces a cation solution has not previously been used to calculate unfrozen water content. In this paper, it is assumed that the residual unfrozen water at very low temperatures (below −18°C) is held within the adsorption‐layer solution and that the remaining unfrozen water within the influence of surface effects is the cationic solution in the diffuse layer. Based on these assumptions, a theoretical model of unfrozen water is established with independent variables of temperature, specific surface area, and electrical double‐layer parameters. While the input parameters of the theoretical model are numerous and difficult to obtain, the theoretical model is simplified as a parametric model. Results of the parametric model are strongly consistent with experimental data within a certain temperature range, supporting the hypothetical conditions. The similarity in the underlying mathematical structure of the derived theoretical and parametric models to current semi‐empirical models further suggests that the surface effects of clay are the main causes of unfrozen water in frozen soil. Key Points: The presence of unfrozen water is explained by surface effects, adsorption forces, and the nature of the electrical double‐layer solutionThe surface effects are defined as the combined actions of molecules and negative charges on the clay surfaceThe residual unfrozen water is a stable adsorption‐layer solution [ABSTRACT FROM AUTHOR]

In this paper, an integrated calibration method for position sensitive detector (PSD) of moving support mechanism in vacuum plasma environment is proposed. That is, the PSD is used to track the laser spot to restore the coordinate information of the signal. Firstly, a PSD integrated calibration principle is proposed to reduce the position error of the signaler by tracking laser points with PSD. Then on this basis, due to the spatial declination angle in the PSD imaging model, a spatial declination correction model was established to compensate the spatial declination error. Finally, there are errors occurred in the measurement because of the nonlinearity of PSD, and the improved backpropagation (BP) neural network calibration algorithm is adopted to further correct the errors through the Fletcher–Reeves linear search method to obtain the accurate coordinate information of the annunciator. MATLAB is used to verify the convergence of the calibration algorithm error. Simulation results show that 951 epochs need to be trained by using the traditional BP algorithm to make the position error converge to 0.001 mm. But when using the improved BP algorithm, only 44 epochs are needed. [ABSTRACT FROM AUTHOR]

During automated fiber placement, insufficient compaction pressure leads to low bond strength between layers and may cause defects like bridging. The compaction roller contacts the prepreg and affects the pressure distribution directly. In this article, a model for analyzing the adaptability of rollers to molds is established. Then, compaction pressure distribution on prepreg tows is analyzed by finite element simulation and verified by pressure sensitive film experiment. Based on the simulation results, a calculation method of pressure uniformity is proposed. Moreover, the design parameters of the roller are optimized with an aim of improving pressure uniformity. The results show that the pressure uniformity can be improved significantly by design optimization of the roller, which indicated that higher bond quality between layers is achieved. [ABSTRACT FROM AUTHOR]

The resilient asynchronous dissipative control problem for Markov jump systems with sector-bounded nonlinearities in the discrete-time domain are examined in this study. The jumps between the system modes and controller modes are considered to be nonsynchronous. The mode transition of the controllers is governed by a nonstationary Markov chain, which can model the asynchronous jumps to different degrees that are also mode-dependent. The nonlinear functions are assumed to belong to sector sets with arbitrary boundaries. The sector boundaries can have positive and/or negative slopes, and therefore, we cover the most general case in our approach. Using the special structure of the system and by constructing a new multiple Lyapunov function, sufficient conditions regarding the existence of desired resilient asynchronous dissipative controllers are obtained in terms of linear matrix inequalities, which ensure the closed-loop system is stochastically stable and strictly dissipative. The designed controller can tolerate additive uncertainties in the controller gain matrix, which results from controller implementations. A numerical example is presented to show the effectiveness of the proposed theoretical results. [ABSTRACT FROM AUTHOR]

Extra-retinal, non-pineal, encephalic photoreceptors (EP) play important roles in mediating development of the reproductive system by the annual change in day length (photoperiodic gonadal response – PGR) in birds. However, the distribution of rhodopsin-like EPs and their functional daily, circadian and seasonal changes are still unclear in the avian brain. This study identifies two novel groups of rhodopsin-immunoreactive cells in the nucleus paraventricularis magnocellularis (PVN) of the hypothalamus and in the medial basal hypothalamus (MBH) in a seasonally breeding species, Gambel’s white-crowned sparrow ( Zonotrichia leucophrys gambelii ) . In the PVN, rhodopsin-ir cell number showed both daily and circadian changes with more labeled cells apparent in the night phase in photosensitive birds, while only circadian changes were observed involving fewer labeled cells in the night phase in photorefractory birds. Single long day photo-stimulation significantly decreased the rhodopsin-ir cell number only in photosensitive birds, coincident with a rise in plasma levels of luteinizing hormone (LH). In the MBH, rhodopsin-ir cell number did not show daily, circadian or single long day induced changes in either photoperiodic states. But, overall these rhodopsin expressing neurons significantly increased from photosensitive to photorefractory states. In the median eminence (ME), more intense rhodopsin-ir was detected in photorefractory birds compared to photosensitive birds. For expression of GnRH and vasoactive intestinal polypeptide (VIP), seasonal differences were found with opposite relationships, consistent with previous studies. Our results suggest different roles of the two groups of rhodopsin-like EPs in the regulation of PGR in white-crowned sparrows. [ABSTRACT FROM AUTHOR]

Large components such as wing sections should be aligned and positioned in a desired position prior to the final manufacturing or assembly, so a digital alignment and position device based on six degree of freedom parallel manipulator with several prismatic-prismatic-prismatic-spherical branches was designed and fabricated to meet the needs. The digital alignment and position device is an alignment device based on the parallel manipulator, and it is also a positioning and holding fixture for large components manufacturing or assembly. In order to effectively and efficiently select the supporting points of large component where the digital alignment and position device branch is connected with, the performance of the parallel manipulator and the fixture should be comprehensively analyzed at the same time. The global performance indices such as the dexterity index, the bearing capacity index, and the stiffness index are calculated based on the mechanism Jacobean matrix of the parallel manipulator, and the positioning stability index is calculated based on the position Jacobean matrix of the fixture. The results show that the global performance indices are not related to the pose, but the positioning stability index is; in addition, all indices rely on the originally selected supporting points and provide the basis for the effective selection of the supporting points for large component aligned and positioned by the digital alignment and position device, which is based on parallel manipulator with prismatic- prismatic-prismatic-spherical pairs. [ABSTRACT FROM AUTHOR]

With the rapid deployment of utility-scale photovoltaic (PV) plants, the impact of PV plants on the environment is a new concern of the scientific and social communities. The exchange of sensible and latent heat energy and mass between land and air in PV plants is crucial to understanding its impact. It is known that the near surface turbulence characteristics rule the exchange. Therefore, it is essential for understanding the impact to study the characteristics of near surface turbulence. However, it is not well recognized. Turbulent fluxes and strength characteristics for the PV plant and the adjacent reference site in the Xinjiang Gobi area were investigated in this study. Various surface layer parameters including friction velocity, stability parameter, momentum flux, and turbulent flux were calculated using eddy correlation system. Results indicate that compared to the reference site, near the surface boundary layer was more unstable during the daytime due to the stronger convection heating, while it was more stable at night in the PV plant. In the PV plant, I u was weakened and I v was strengthened during the daytime, and I u and I v were all weakened at night, while I w was strengthened across the whole day. The significant difference between I u and I v in the PV plant indicated that the horizontally turbulence strengths were affected by the plant layout. The turbulent kinetic energy of the PV plant was lower than the reference site and the momentum in the PV plant was higher than the reference site, especially during the daytime. Compared to the reference site, the PV plant had a higher sensible heat flux and less latent heat flux. The turbulent components of wind followed the 1/3 power law in the unstable conditions and stable conditions in the PV plant and the reference site. [ABSTRACT FROM AUTHOR]

Solar photovoltaics (PV) has advanced at an unprecedented rate and the global cumulative installed PV capacity is growing exponentially. However, the ability to forecast PV power remains a key technical challenge due to the variability and uncertainty of solar irradiance resulting from the changes of clouds. Ground-based remote sensing with high temporal and spatial resolution may have potential for solar irradiation forecasting, especially under cloudy conditions. To this end, we established two ultra-short-term forecasting models of global horizonal irradiance (GHI) using Ternary Linear Regression (TLR) and Back Propagation Neural Network (BPN), respectively, based on the observation of a ground-based sky imager (TSI-880, Total Sky Imager) and a radiometer at a PV plant in Dunhuang, China. Sky images taken every 1 min (minute) were processed to determine the distribution of clouds with different optical depths (thick, thin) for generating a two-dimensional cloud map. To obtain the forecasted cloud map, the Particle Image Velocity (PIV) method was applied to the two consecutive images and the cloud map was advected to the future. Further, different types of cloud fraction combined with clear sky index derived from the GHI of clear sky conditions were used as the inputs of the two forecasting models. Limited validation on 4 partly cloudy days showed that the average relative root mean square error (rRMSE) of the 4 days ranged from 5% to 36% based on the TLR model and ranged from 12% to 32% based on the BPN model. The forecasting performance of the BPN model was better than the TLR model and the forecasting errors increased with the increase in lead time. [ABSTRACT FROM AUTHOR]

Fish-lighting complementary photovoltaic power station organically combines aquaculture and renewable energy. In this study we aimed to develop a solar photovoltaic that is not confined to land. We used a shade net to simulate photovoltaic panels, and studied the effects of different proportions of photovoltaic panels on water and fish. The results showed that the average light intensity of the unshaded area and the shaded area were 16,661.7 Lux and 2437.0 Lux. The average light intensity of the shaded area was 85.4% lower than that of the unshaded area. The effective range of the shaded area for the light intensity of the water layer was 0 cm~30 cm. The temperature and pH in the water body showed a linear decreasing trend with the increase of the photovoltaic deployment ratio, and the dissolved oxygen showed an inverted "U"-shaped change characteristic, but this effect was limited. When the photovoltaic deployment ratio was 25% to 75%, the dissolved oxygen in the water body increases by an average of 2.37% compared to the unshaded area. The appropriate proportion of photovoltaic deployment did not affect the dissolved oxygen content in the water body. When the photovoltaic deployment ratio reached 75%, the number of algae species and algae biomass was the largest, and the fish production was the highest at 8094.6 kg·acre−1, which is an increase of 166.2 kg·acre−1 compared to the average yield in unshaded areas. Therefore, photovoltaic layout will not affect the growth of fish, and the proportion of 75% is the best layout choice. [ABSTRACT FROM AUTHOR]

• Artificial light at night changed circadian rhythm of bird locomotive activity. • Artificial light at night suppressed melatonin secretion of tree sparrow. • Intestinal microbial community of tree sparrow was altered by urban light pollution. Artificial light at night (ALAN) or light pollution is rapidly widespread with fast urbanization and becomes an obvious environmental disturbance. Recent studies showed ALAN has multiple negative impacts on a wide range of species including bird biological rhythm disruption, behavioral and physiological disturbance and hormone secretion disorder. However, its effects on bird gut microbiota are scarcely studied. In this study, we used Eurasian tree sparrow (Passer montanus), a widely distributed and locally abundant bird species in both urban and rural areas of China to examine the effects of ALAN on locomotor activity rhythm and melatonin secretion, and species diversity and community structure of intestinal microbiota by simulating urban and rural night light environment. Our results showed ALAN strongly affected circadian rhythm of locomotor activity with earlier start of activity before light-on and later rest after light-off. Moreover, ALAN significantly suppressed melatonin release. Last but not least, ALAN profoundly affected taxonomic compositions, species diversity and community structure of intestinal microbiota of birds. We concluded that ALAN may cause bird health damage by disrupting circadian rhythm, inhibiting melatonin release and altering intestinal microbiota. Melatonin hormone level and intestinal microbiota diversity may be important bioindicators for light pollution. [ABSTRACT FROM AUTHOR]

Lead (Pb) is one of the most hazardous metals to human and wildlife and it also has multiple negative impacts on birds. However, its influences on bird gut morphology and intestinal microbiota were still unclear. We used female Japanese quails (Coturnix japonica) to examine the effects of chronic lead exposure (0, 50 ppm and 1000 ppm) on cecal histology, microbial communities and immune function. The results showed 50 ppm lead exposure caused subtle damages of cecum cell structure. However, 1000 ppm lead exposure caused severe cecum histopathological changes characterized by mucosa abscission, Lieberkühn glands destruction and lymphocyte proliferation. Moreover, both lead concentrations induced ultrastructural damages featured by nucleus pyknosis, mitochondrial vacuolation and microvilli contraction. Meanwhile, microbial community structure, species diversity, taxonomic compositions and taxa abundance in the cecum were affected by lead exposure. Furthermore, the mRNA relative expression of immunity-related genes such as interleukin 2 (IL-2) and gamma interferon (IFN-γ) was significantly downregulated while that of interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and natural killer kappa B (NF-κB) was significantly upregulated in the cecum of 50 and 1000 ppm lead exposure groups. We concluded that lead exposure may cause gut health impairment of female Japanese quails by inducing cecal histopathological changes, microbiota dysbiosis and cecal immune disorder. • Chronic lead exposure led to cecal histopathological damages in Japanese quails. • Ultrastructural impairment of the cecum was caused by lead exposure. • Cecal microbial community structure and diversity were perturbed by lead stress. • The expression of immunity-related genes in the cecum was altered by lead exposure. [ABSTRACT FROM AUTHOR]

The accurate prediction of surface solar irradiance is of great significance for the generation of photovoltaic power. Surface solar irradiance is affected by many random mutation factors, which means that there are great challenges faced in short-term prediction. In Northwest China, there are abundant solar energy resources and large desert areas, which have broad prospects for the development of photovoltaic (PV) systems. For the desert areas in Northwest China, where meteorological stations are scarce, satellite remote sensing data are extremely precious exploration data. In this paper, we present a model using FY-4A satellite images to forecast (up to 15–180 min ahead) global horizontal solar irradiance (GHI), at a 15 min temporal resolution in desert areas under different sky conditions, and compare it with the persistence model (SP). The spatial resolution of the FY-4A satellite images we used was 1 km × 1 km. Particle image velocimetry (PIV) was used to derive the cloud motion vector (CMV) field from the satellite cloud images. The accuracy of the forecast model was evaluated by the ground observed GHI data. The results showed that the normalized root mean square error (nRMSE) ranged from 18.9% to 21.6% and the normalized mean bias error (nMBE) ranged from 3.2% to 4.9% for time horizons from 15 to 180 min under all sky conditions. Compared with the SP model, the nRMSE value was reduced by about 6%, 8%, and 14% with the time horizons of 60, 120, and 180 min, respectively. [ABSTRACT FROM AUTHOR]

Abstract This study concerns a computational model for the postbuckling failure mechanism of composite T-stiffened panels with different bonding methods. The model is then validated against the available experiments and excellent agreement is obtained. Further, the model is used to predict the postbuckling behavior of the stiffeners co-cured, co-bonded, and secondary bonded to the skin, where the new separation phenomenon including margin cohesive failure, local debonding, and global debonding are captured. Moreover, a parametric study is also carried out to investigate the effect of skin-stiffener interface energy and strength on the postbuckling response of composite panels. The numerical results show that the bonding method has little effect on the uniaxial compressive stiffness of the composite T-stiffened panel, but influences the collapse load and failure process by affecting the skin-stiffener interface behavior. Besides, the collapse load and the failure mode are influenced by the ratio of the interface strength to the interlaminar shear strength. The fiber failure location and shape of load-shortening curve are affected by the ratio of the interface energy to the interlaminar fracture energy. [ABSTRACT FROM AUTHOR]

In order to identify impacts of photovoltaic (PV) power plant on surface radiation, this paper conducted a comparative study on the surface radiation and surface albedo characteristics between the PV site and reference site in the Gobi area in Xinjiang, China in the summer of 2020. The results show that, the upward long-wave radiation at the PV site was significantly lower than that at the reference site in the night, while the two were basically the same during the daytime. The average surface albedo at the PV site (0.14) was 39.1% lower than that at the reference site (0.23). Net radiation was higher at the PV site than that at the reference site throughout the whole day. The average net radiation of the underlying surface at the PV site was 30.7% more than that at the reference site, 75% of which was contributed by lower upward shortwave radiation and 25% was due to nocturnal lower upward longwave radiation at the PV site. • Average surface albedo at photovoltaic power site decreases 39.1%. • Upward long-wave radiation at photovoltaic power site decreases significantly. • Average net radiation at photovoltaic power site increases 30.7%. [ABSTRACT FROM AUTHOR]