POD Analysis Research Articles

Genome-wide association study of appearance quality traits and development of KASP makers in vegetable soybean

Vegetable soybean [(Glycine max (L.) Merr.], commonly referred to as edamame, holds significant agricultural importance in China as a legume vegetable harvested at the pod-filling stage (R6). The visual appeal of vegetable soybeans, crucial for consumer preference and marketability, depends on factors such as pod length, pod width, and pod color. This study cultivated 264 vegetable soybeans in Nanjing, Huai'an, and Nantong to assess pod traits using PlantPhenoM, a system for pod phenotypic identification and analysis. Results revealed a variability range of 8.64 to 30.00% in appearance quality traits among vegetable soybeans. Leveraging phenotypic data and employing a genome-wide association study (GWAS) we identified 525 SNPs significantly linked to appearance quality traits in different regions. In addition, candidate genes (Glyma.04G004700, Glyma.15G051600, Glyma.18G225700, Glyma.18G225900, and Glyma.18G272300) associated with target traits were identified, and KASP markers for S04_372771 (pod length), S18_51477324 (pod width), and S18_55553200 (pod color) were developed, respectively. This research offers valuable insights for breeding superior vegetable soybean varieties and lays the groundwork for exploring candidate genes and molecular markers related to appearance and quality traits in vegetable soybeans.

Determination of the regulatory network of two bZIP transcription factors, AhHYH and AhHY5, in light signal regulation in peanut by DAP-seq

Members of bZIP gene family play crucial roles in various biological processes, including plant growth and development, stress response, and light signal transduction. Despite their significance, there is limited information on the function of the bZIP gene family in peanuts. In this investigation, we identified a total of 99 bZIP gene family members in the peanut genome, distributed across 20 chromosomes. Phylogenetic tree analysis categorized the peanut bZIP gene family into 10 groups, with groups I, D, A and S being the most widely distributed. Transcriptome analysis of peanut pods revealed that 10 bZIP family genes exhibited significant induction in response to light, suggesting their potential involvement in light signal transduction in peanuts. Within the peanut bZIP family, group H comprises six genes AhbZIP13, AhbZIP63, AhbZIP39, AhbZIP44, AhbZIP91 and AhbZIP96. Particularly, the expression of the AhbZIP63 (AhHYH) gene significantly increased under light induction, indicating a pivotal role in light signal transduction. DAP-seq analysis of AhbZIP63 (AhHYH) demonstrated its direct regulation of genes associated with UV response and cellular response to nutrient levels.

MÔ PHỎNG XOÁY TÁCH RỜI TRONG NGHIÊN CỨU CÁC ĐẶC TRƯNG KHÍ ĐỘNG CỦA DÒNG CHẢY RỐI TRÊN VÙNG TƯƠNG TÁC

The turbulent mixing layer is a phenomenon that occurs and has many applications in aeronautical engineering. The study of mixing layer turbulence by the numerical method is suitable under domestic conditions. Two numerical simulation methods are used in most studies including, direct numerical simulation DNS and large eddy simulation LES, while there are very few studies using detached eddy simulation DES. In this article, the authors use numerical simulation methods evolving Reynolds average Navier-Stokes simulation RANS and detached eddy simulation DES to propose a numerical simulation model that allows to study of the aerodynamic characteristics of the turbulent flow interaction. RANS is used to evaluate grid independence. With the selected mesh, two models counting the DES-2D model and the DES-3D model are conducted. Processing velocity field data with Matlab code, the results show that the average flow behavior has closely followed the experimental results, while the turbulent kinetic energy still has a large error. POD and Q-criterion analysis has shown some large coherent structures in the interaction region.

Inspectability and POD investigation for optical solar reflector bonded satellite panels

Optical Solar Reflectors (OSR) are fully light-reflective materials, which are used in satellite panels that bonded with metallic sheets with a layer of silicon type adhesive. During the bonding process, entrapping of air bubbles in the bondline is the main problem, and the detection of air bubbles is crucial for the thermal integrity of the panel. The inspectability investigation established in this work is a complete methodology that consists of the determination of the applicable NDT method, parameter optimization, reference specimen design, and most importantly, execution of the POD analysis for the detection reliability to implement the method into post-manufacturing NDI operations of OSR panels. A comprehensive comparison of conventional and advanced inspection methods were performed in this study, including sonic, ultrasonic, radiographic and thermographic techniques. After trials on generic scale panels, high sensitivity surfaces of OSR and large density differences of bonded elements lead to the selection of the lockin thermography technique. Next, an appropriate reference specimen was designed for the POD approach with thermally representative artificial defects. The results show that the lock-in thermography technique can detect air bubbles at the adhesive layer for sizes larger than 20 mm2 with a probability of detection of 90% at a confidence level of 95%.

Differential transpiration between pods and leaves during stress combination in soybean.

Climate change is causing an increase in the frequency and intensity of droughts, heat waves, and their combinations, diminishing agricultural productivity and destabilizing societies worldwide. We recently reported that during a combination of water deficit (WD) and heat stress (HS), stomata on leaves of soybean (Glycine max) plants are closed, while stomata on flowers are open. This unique stomatal response was accompanied by differential transpiration (higher in flowers, while lower in leaves) that cooled flowers during a combination of WD + HS. Here, we reveal that developing pods of soybean plants subjected to a combination of WD + HS use a similar acclimation strategy of differential transpiration to reduce internal pod temperature by approximately 4 °C. We further show that enhanced expression of transcripts involved in abscisic acid degradation accompanies this response and that preventing pod transpiration by sealing stomata causes a significant increase in internal pod temperature. Using an RNA-Seq analysis of pods developing on plants subjected to WD + HS, we also show that the response of pods to WD, HS, or WD + HS is distinct from that of leaves or flowers. Interestingly, we report that although the number of flowers, pods, and seeds per plant decreases under conditions of WD + HS, the seed mass of plants subjected to WD + HS increases compared to plants subjected to HS, and the number of seeds with suppressed/aborted development is lower in WD + HS compared to HS. Taken together, our findings reveal that differential transpiration occurs in pods of soybean plants subjected to WD + HS and that this process limits heat-induced damage to seed production.

On POD-based modal analysis in simulations of granular flows

Understanding the dynamics of granular flows is of great significance in various engineering fields but challenging because of flow complexity. The discrete element method (DEM) is often employed in simulations of various granular systems. Recently, modal analysis has been shown to remarkably deepen the understanding of these systems. The principle of the modal analysis is to extract a set of dominant structures from experimental or numerical datasets. In this study, an advanced modal analysis technique, i.e., the Lanczos-based proper orthogonal decomposition (LPOD), is incorporated into numerical simulations of a particle system. Two types of applications are presented. First, the modal analysis based on the LPOD technique is adopted to evaluate particle mixing in a rolling drum. It is demonstrated that the POD-mode distributions of particle movements can reveal dominant mechanisms, such as convection/diffusion. Second, the LPOD technique based modal analysis is employed to validate the adequacy of a coarse-grained DEM in a spouted bed. The results show that similar patterns of POD modes and related energy spectra are observed in the original particle and the coarse-grained particle systems. Consequently, not only can POD analysis be used to identify main mixing mechanisms, but also POD results are shown to be new effective parameters in the validation of the coarse-grained DEM. • An advanced Lanczos-based POD (LPOD) was employed to analyze granular phenomena. • Applicability of the LPOD was shown in simulations of a drum and a spouted bed. • LPOD was demonstrated to effectively identify main mixing mechanisms. • LPOD provided new parameters to effectively validate a coarse-grained DEM.

Characterization of shock-induced panel flutter with simultaneous use of DIC and PIV

In this experimental study, panel flutter induced by an impinging oblique shockwave is investigated at a freestream Mach number of 2, using the combination of planar particle image velocimetry (PIV) and stereographic digital image correlation (DIC) to obtain simultaneous full-field structural displacement and flow velocity measurements. High-speed cameras are employed to obtain a time-resolved description of the panel motion and the shockwave-boundary layer interaction (SWBLI). In order to prevent interference between the PIV and DIC systems, an optical isolation is implemented using fluorescent paint, dedicated light sources, and camera lens filters. The effect of the panel motion on the SWBLI behavior is assessed, by comparing it with the SWBLI on a rigid wall. The results show that panel oscillations occur with a maximum amplitude of ten times the panel thickness. The dominant frequencies observed in the panel oscillation (424 Hz and 1354 Hz) match the main spectral content of the reflected shockwave position. A further POD analysis of the panel displacement spatial distribution shows that these two frequency contributions are well captured by the first two POD modes, which correspond, respectively, to a first and a third bending mode shape and account for 92% of the total oscillation energy. The fluid-structure coupling is studied by identifying, in the flow, the regions of maximum correlation between the panel displacement and the flow velocity fluctuations. The results obtained prove that the inviscid flow region upstream of the SWBLI is perfectly in phase with the panel oscillation, while the downstream region has a delay of one quarter of the flutter cycle.

Development of a cost effective approach toward energy efficient buildings by design, fabrication and economical analysis of air conditioning pods: A case study of a bus station in Thailand

Energy consumption by air conditioners in buildings is 57% around the globe. However, particularly in Thailand percentage of energy consumption is 18.6% by bus stations due to the massive tourism. The current study aims to provide feasibility and economical analysis of small air conditioning (AC) pods at a bus station located in Hat Yai Thailand by design, fabrication and experimental investigation. As there is no need to cool complete waiting area. An economic analysis is performed in Homer Pro software. According to the results, thermal load calculated for Pod is 1236 W. COP of the system is 1.5. Moreover, proposed system is 9.5% more economical than pre working system with the payback period of 1.72years. Also, per unit cost of electricity after installation AC pods reduces by 31%. Moreover, The AC pod successfully lowered the cabin temperature down till 17 °C by using only 4.9 A and 1127 W. Current research can be used to provide thermal comfort to travelers at airports, subway or train stations or in office as a separate cabins using less amount of energy. Also, it will be a milestone towards development of simulation based small AC installations in commercial sectors, to save cost and energy in Thailand.

Effects of free-stream turbulence on motion-induced aerodynamic forces of a long-span flexible flat roof using LES simulations

This study aims to investigate the effects of free-stream turbulence on motion-induced aerodynamic forces of a long-span flexible flat roof. Large-eddy simulations (LES) of both rigid and forced vibrating roofs under different free-stream turbulence conditions are performed to obtain the aerodynamic forces and flow field data simultaneously. Firstly, the LES simulations of the rigid and vibrating roofs are validated against the reference experiments. And then, characteristics of the distributed pressures on vibrating roofs under free-stream flow turbulence conditions with different turbulence intensities are elucidated. Moreover, the motion-induced forces acting on the vibrating roof under different turbulence conditions are identified and compared, in which the power spectra of wind forces and aerodynamic damping and stiffness are examined. Furthermore, the underlying flow mechanism of the turbulence effects on the motion-induced forces is investigated based on POD analysis of the flow around the vibrating roof. It is found that dual effects exist between the influences of free-stream turbulence and roof motion on the aerodynamic forces, the motion-induced aerodynamic forces on the roof would be greatly decreased with the increase of free-stream turbulence, and the motion-induced effects become less dominant under high free-stream turbulence. The outcomes of this study would facilitate our understanding of the role played by the motion-induced aerodynamic forces and improve the wind-resistant design of long-span roof structures for engineering practices.

LES Analysis of the Effect of Snowdrift on Wind Pressure on a Low-Rise Building

This paper presents a comparative study of the distribution of wind pressure acting on a low-rise building roof with or without snowdrift through the Large-Eddy simulation (LES) method. Firstly, based on previous wind-blowing snow experiments, the stable snowdrift models were obtained by reverse technique. Secondly, the methodology of LES numerical simulation was introduced, where sensitivity analyses were conducted to determine a more reasonable grid configuration and data sampling time. Meanwhile, the numerical validation was also verified by comparing it with the previous PIV database. Finally, the wind pressure acting on the building’s roof with or without snowdrift were systematically compared and analyzed. It was found that the snow cover significantly restrains the size of the separation bubble and makes is lcoated earlier on the roof, which leads to the increasing passing velocity in the region near the roof. Meanwhile, the area-averaged pressure coefficient in the windward region (x/H < 0.5) for the snowdrift roof will be significantly amplified, especially for the fluctuating pressure, the maximum value of the Relative Difference even reaches 40%. Additionally, according to the POD analysis, the snowdrift causes the fluctuating wind energy to concentrate near the windward side of the roof. Therefore, more attention should be paid to the wind pressure in the windward region when the snowdrift is formed on the roof.

Meta analysis on color, total flavonoids, antioxidants, frictional, mechanical, and cutting force of moringa pods

AbstractThe color, total flavonoids, antioxidants, frictional and mechanical properties (bending stress, hardness, puncture force, peak cutting force) and cutting power requirement of moringa pod was studied and reported. Drying curves exhibited the falling rate drying characteristics with drying rate constant (k) (−1.18 × 107–.00571 m−1) and effective moisture diffusivities (1.500 × 10−6–2.817× 10−8 m2 s−1). The Page model with high R2 (.997–.8282) and low value (.00119–.000927) shows the best fit on drying curves. The L*, a*, b* and total difference in color values varied from 47.05 to 32.5; −9.89 to 6.41; 35.76–21.07; and .07–21.07, respectively. The chlorophyll content (.353–.264 mg/g dm) and the total flavonoids (1.3023–.1050 mg QE/g dm) were recorded. The total phenolics (5.4–21.739 mg GAE/g dm) showed an increasing trend whereas the antioxidant activity (31.5102–20.922%) decreased with increasing drying temperature. The bending stress, hardness, and puncture force ranged from 6514.38 to 1189.33 N/mm2; from 14.707 to 225.16 N; from 267.625 to 25.364 N. The peak cutting forces; and power requirement for cutting on the horizontal and longitudinal direction of moringa pods were 94.67–27.27 N and 179.95–73 N; and .249–.704 W and .434–1.124 W; respectively. The SEM analysis of moringa pods substantiated the variations in mechanical properties through microstructural changes. The results indicated that aspect ratio significantly affected the drying characteristics, frictional, and mechanical properties of moringa pods. Therefore, the aspect ratio can be considered while designing cutting tools, conveying, and processing equipment.Practical ApplicationsMoringa pods are used as a vegetable in curries, soups, and cuisines in significant parts of Asia and Africa. It has good nutritional characteristics and a very tempting flavor and aroma. However, the processing and value addition of moringa lack owing to primary processing tools and value addition machines because of the non‐existence of frictional, mechanical properties, and cutting force data concerning size, that is, aspect ratio and moisture content. The study's findings can help design and develop the cutters, tools, machines, and conveyors used for the primary processing and value addition of moringa pods.

Preheated liquid jet breakup dynamics in a twin-fluid injector

• Effect of liquid preheating on primary jet breakup in twin-fluid injector is studied. • Jet breakup length, KH and flapping instabilities are experimentally characterized. • Measured parameters show considerable variation with T l beyond M ≈ 6 . • L ¯ / D l , when scaled appropriately using Oh , depends solely on St KH , though for M < 6. • Jet flapping governs breakup length fluctuations without/with liquid preheating. This paper aims to investigate the influence of liquid preheating on primary jet breakup in a coaxial twin-fluid injector. The injector was operated over a broad range of conditions. Three different liquid injection temperatures were realized. Time-resolved shadowgraphic images of the liquid jet breakup were recorded using a high-speed camera. The images were analysed to measure various parameters including effective jet diameter at the nozzle exit, the mean and fluctuations of the jet breakup length, as well as time-scale of Kelvin–Helmholtz (KH) instability. The jet flapping instability was characterized by POD analysis. Even moderate liquid preheating is found to strongly influence the jet breakup behaviour. Different trends of the measured jet breakup parameters with respect to liquid injection temperature are identified depending on gas-to-liquid momentum flux rati M , being larger or smaller than about 6. In this context, the roles of KH and flapping instabilities are explained.

A coupled phase-invariant POD and DMD analysis for the characterization of in-cylinder cycle-to-cycle flow variations under different swirl conditions

A coupled phase-invariant POD and DMD analysis for the characterization of in-cylinder cycle-to-cycle flow variations under different swirl conditions

Wake Patterns Around Front Tyre And Wheel On Vehicle Dynamics Clarified By On-Board PIV Application

Temporal and spatial wake patterns and behaviors around rotating tires and wheels are some of the most critical flow phenomena on aerodynamic performance and vehicle dynamics. In particular, aerodynamic drag is one of the most important factors on greenhouse effect gas and fuel efficiencies, in these days remarkably focused on the shift from conventional fossil fuel power plants to electric ones to prevent the global warming. From the point of view of aerodynamics, OEMs' wind tunnel facilities with moving ground and high fidelity CFD tools are employed to optimize the exterior body shape and aerodynamic device in order to reduce the aerodynamic drag. Recently, high fidelity CFD tools which include tire rotations are easily employed by users, not only specialists, to analyze the flow around the vehicle and to optimize the exterior design at the development phase. However, more accurate and detailed understanding of complicated flow phenomena around vehicle during motion are required to predict these flow phenomena accurately by CFD tools at early development phase. Moreover, the more detailed experimental investigation is essential for the aerodynamicists, not only to develop the prediction tool but also to understand the flow phenomena around vehicle in its essence. Therefore, in this study, the on-board 2D-3C PIV measurement system in wind tunnel facility has been developed to investigate the wake patterns around rotating front tire and wheel. As result, the critical wake patterns have been clarified by POD analysis of the mentioned on-board 2D-3C PIV measurement data. These front wheelhouse wake patterns were classified in terms of the wake generation locations that produced the aerodynamic drag. These results indicate that there is the potential for an improvement in not only aerodynamic drag and but also vehicle dynamics by flow control to suppress the wake generations around front wheelhouse and the flow fluctuation around bodyside, moreover, this system can be applied to real world running condition in near future.

Reliability Assessment of PAUT Technique in Lieu of RT for Tube Welds in Thermal Power Plant Facilities

In this study, a reliability evaluation of the phased array ultrasonic testing (PAUT) method was performed to examine the applicability of the method for tube weld specimens with flaws having the same specifications as the tubes in the boilers of thermal power plant facilities. To this end, test specimens were fabricated by inserting flaws into tube welds with identical materials and specifications to those used in the thermal power plant. PAUT data acquisition was obtained using a round robin test (RRT) on the fabricated specimen, and the data were compared with the results of radiographic testing (RT) for a comparative evaluation of the flaw detection performance. In addition, for quantitative reliability analysis, the flaw detection performance (probability of detection; POD) and the error in the sizing accuracy (root-mean-square error; RMSE) were calculated with different materials of the specimens (carbon steel, stainless steel, dissimilar metal) and flaw types (volumetric, planar). In the analysis results, for high-risk planar defects, the PAUT technique exhibited superior flaw detection performance to the RT technique. A POD analysis of the PAUT technique indicated that flaws of 6.9 mm length were detected at 80% probability for total tube specimens. Furthermore, a reliability analysis was performed for test specimens of different materials and flaw types, and the results were derived. Through the findings of this study, the applicable range of the PAUT technique was examined, and a technical basis for PAUT in lieu of RT was established.

A new data assimilation method of recovering turbulent mean flow field at high Reynolds numbers

This paper proposes a new data assimilation method for recovering the high-fidelity turbulent mean flow field around airfoil at high Reynolds numbers based on experimental data, which is called Proper Orthogonal Decomposition Inversion (POD-Inversion) data assimilation method. Aiming at flows including shock wave discontinuities or separation at high angles of attack, the proposed method can reconstruct the high-fidelity mean flow field combined with experimental force coefficients. We firstly perform the POD analysis to turbulent eddy viscosity fields computed by the SA model and obtain base POD modes. Then the POD coefficients are optimized by global optimization algorithm coupling with computational fluid dynamics (CFD) solver. The high-fidelity turbulent mean flow fields are recovered by several main modes, which can dramatically reduce dimensions of the system. The effectiveness of the method is verified by cases of transonic flow around the RAE2822 airfoil at high Reynolds numbers and the separated flow around S809 airfoil at high angles of attack. The results demonstrate that the proposed data assimilation method can recover turbulent flow fields which optimally match the experimental data, and can significantly reduce the error of aerodynamic coefficients. Furthermore, the proposed method can provide high-fidelity mean field data to establish turbulence models based on machine learning.

Transcriptomic and Metabolomic Analyses Reveal a Potential Mechanism to Improve Soybean Resistance to Anthracnose.

Anthracnose, caused by Colletotrichum truncatum, leads to large-scale reduction in quality and yield in soybean production. Limited information is available regarding the molecular mechanisms of resistance to anthracnose in soybean. We conducted a transcriptomic and targeted metabolomic analysis of pods from two soybean lines, “Zhechun No. 3” (ZC3) and ZC-2, in response to C. truncatum infection. Factors contributing to the enhanced resistance of ZC-2 to anthracnose compared with that of ZC3, included signal transduction (jasmonic acid, auxin, mitogen-activated protein kinase, and Ca2+ signaling), transcription factors (WRKY and bHLH), resistance genes (PTI1, RPP13, RGA2, RPS6, and ULP2B), pathogenesis-related genes (chitinase and lipid transfer protein), and terpenoid metabolism. Targeted metabolomic analysis revealed that terpenoid metabolism responded more promptly and more intensely to C. truncatum infection in ZC-2 than in ZC3. In vitro antifungal activity and resistance induction test confirmed that jasmonic acid, auxin signaling and terpenoids played important roles in soybean resistance to anthracnose. This research is the first study to explore the molecular mechanisms of soybean resistance to anthracnose. The findings are important for in-depth analysis of molecular resistance mechanisms, discovery of resistance genes, and to expedite the breeding of anthracnose-resistant soybean cultivars.

High-fidelity modeling of turbulent shear flow downstream of a 3-D airfoil with spanwise ice contamination leading stall

The characteristics of turbulent shear flow downstream of NACA23012 airfoil with ridge-ice contamination leading stall are investigated in this paper. A low-dissipated compressible N–S solver is employed to simulate its unsteadiness via Improved Delayed Detached Eddy Simulation (IDDES) with sufficient spatial and temporal resolution. Nonlinear phenomena of eddy dynamics, such as vortex pairing, shedding, merging and breaking down, are fully resolved with extremely fine grid scale over 0.2 billion. The calculated Reynolds number based on the airfoil chord length is near 2.1×106. High-fidelity results show that the turbulent shear stream quickly develops into tubular geometry after leaving the ridge. The shedding-off tubular geometries quickly show anisotropy, twist in all directions, and finally decomposed into turbulence. Large-scale structural interaction is found above the trailing edge zone, determined by the shedding-off vortex and the rolling-up flow from the lower surface of the airfoil. Using POD and DMD analysis, we make sense it as the cause of low-frequency oscillation of the shear layer and even the lift fluctuation.

Experimental and numerical study on the horizontal-vertical pneumatic conveying system with pulse excitation flow based on POD and recursive analysis

To solve the problem of energy loss during pneumatic conveying, a new energy-saving method of pneumatic transportation, pulse excitation flow, is proposed and applied to the transportation of petroleum coke. Firstly, the minimum pressure drop velocity of petroleum coke transported by pulse excitation flow is obtained through experimental research, and then the energy-saving mechanism of pulse excitation flow is explored through CFD-EDM coupling. The experimental results show that the energy loss coefficient of pulse excitation flow is reduced by 12.6% compared with axial flow. The numerical results show that the pulse excitation flow will produce alternating positive and negative vortices, and using the pulse excited flow conveying can make the particles enter the suspension region 6D earlier and reduce the energy loss, which further indicates that the gas–solid coupling effect of the pulsed excitation flow is more conducive to the dispersion and acceleration of the particles compared with axial flow.

Experimental investigation of the flow-spray field in a realistic concentric staged high-temperature-rise combustor

The present work investigated the flow and spray fields in a realistic concentric staged high-temperature-rise (HTR) combustor in isothermal conditions using high-speed (10 kHz) particle image velocimetry (PIV) and 10 Hz kerosene planar laser-induced fluorescence (kerosene-PLIF). The two stages of the combustor, including a pilot stage and a main stage, were operated both individually and jointly to investigate their corresponding flow fields and the interactions between the flow from the two stages. From the time-averaged flow field results, strong coupling between the pilot and main swirling flows has been identified, leading to the formation of a primary recirculation zone (PRZ) and a lip recirculation zone (LRZ). From the instantaneous flow fields, the presence of a precessing vortex core (PVC) was observed when the two stages were flowing jointly, and the dominant PVC unsteady motions located in the inner shear layer of the pilot swirling was identified using snapshot proper orthogonal decomposition (snapshot POD) with dominant frequencies at 1400 and 1515.4 Hz. Comparing the flow field with the spray field indicates that the unsteady flow motion, in addition to the mean bulk flow, plays a key role in the understanding of the spray distribution. Noticeably, it is shown in present study that the dominant unsteady flow motions properly captured from the POD analyses show good agreement with some primary features of the spray distribution, which can be valuable to unraveling the complex flow-spray coupling in the HTR combustor operated under realistic conditions.