Effects Of Extreme Conditions Research Articles

Physics-informed reinforcement learning for probabilistic wind power forecasting under extreme events

With wind power penetration increases, accurate and reliable wind power forecasting is becoming gradually critical, and data driven model is a promising solution to implement this task. However, limited by deficient data samples under extreme conditions, scarcity of feature measurements fails to meet the number of training samples required, making the forecasting model exhibits low adaptability. This paper proposes a physics-informed reinforcement learning based method for probabilistic forecasting. Analytical physical expression of wind power output under extreme event is established to construct the error evaluation function for abrupt feature. Deep deterministic policy gradient-based quantile fitting model is then proposed, with abrupt feature embedded as the auxiliary input data for neural network. On this basis, parameter training technique under small data set is proposed to deal with the effect of extreme conditions on correction process of network. It extracts key historical transitions from experience replay pool to establish effective training samples, and model parameters are updated through the small-batch learning strategy to minimize long-term error feedback. Test result on the practical cold wave event of wind farms in China shows effectiveness of the proposed method.

Wind-snow interactions at the Ojos del Salado region as a potential Mars analogue site in the Altiplano - Atacama desert region

We describe the general characteristics and interactions happening at a unique, potential new Mars analogue site, located in the Altiplano and Atacama Desert region: the Ojos del Salado inactive volcano. The interaction between rare snowing events and strong winds transported large masses of porous volcanic grains there could produce decimeter - meter thick buried snow masses fast, shielded against sublimation for extended periods (years). Subsurface temperature logging suggests that water ice melting is rare and surface modification is dominated by desiccation of the cryosphere and wind activity – just like on Mars. The first analysis of aeolian transported grains in the area points to immature material sized between coarse sand and coarse silt, and indicates the possibility of larger snow occurrence in winter when the site is inaccessible – however further observations are necessary The site contains decameter scale megaripples, which are unusual for Earth and also support the understanding of resemble features on Mars. The shallow subsurface analysis with Mars relevance is supported here by drilled cores of evaporitic sediments presented carbonate, aragonite, anhydrite, talc and clay minerals in the shallow subsurface with Mars relevance. Though the region is generally felsic in composition, basalts can be found at a hillside near Laguna Verde where the effect of extreme conditions (including the strong UV radiation) on rock weathering could be analysed. The temperature, dryness, wind exposure, decreased atmospheric pressure and elevated UV radiation together make Ojos del Salado a unique Mars analogue site, and it is accessible up to 5200 m altitude by regular pick-up trucks via a 5–6 h driving from the Copiapo airport.

ON THE QUESTION OF WAYS OF MOVEMENT CELLS AND SECRETS BY CHANNEL CHANNELS AND DUCTS

To substantiate the possible relationship of the parameters of homeostasis of the concentration of Ca2+, K+, Na+ and the mass of organic and inorganic substances secreted synthesized еt by the tissues of the genital system of males and females (bull – sperm plasma; cow – vaginal mucus), with passive and/or by active methods of movement of sperm and ova through their channels and ducts, the peculiarities of the distribution of components of open and closed systems of the type "environment – cell (substance)" were investigated.
 Methods of spectrophotometric (flame photometry, Flapho-4) and gravimetric (combustion, extraction, elimination) analysis of the studied samples experimentally established that the adaptive response of sperm to the protective and/or harmful effects of extreme conditions (concentration, temperature, properties of protective environment components). Sperm preservation (TCS) is different. Depending on those (exo-) or other (endogenous) circumstances, the antiportic way of moving ions can change to symportic.
 The peculiarities of the parameters of concentration and mass of the components of the studied systems revealed in this connection indicate that the fractions of aqueous extracts (PVE) of tissues and secretions of bull and cow, at different functional states of genitals (norm, pathology), have different concentrations of free of bound alkali metal ions, mass and content of substances of their dry residue eliminated in distilled water and insoluble (water, acids).
 The limit of the difference of the ratio of the ratio (IC:1) of the concentration of one- (Ca2+:Ca2+, K+:K+, Na+:Nа+) and different (Na+:Ca2+, K+:Ca2+, Na+:K+) pairs of ions indicates that that the limit of osmotic pressure parameters of the organic and inorganic components of samples of tissues of genitals, sperm and uterine-vaginal mucus can also be different.
 This suggests that different parameters of osmotic pressure of the components of the synthesized secretions and the formed sperm and eggs create (initiate, stimulate, inhibit) favorable conditions for their passive and/or active movement through the channels and ducts of the genitals. However, it should be added that the proposed hypothesis requires discussion and experimental confirmation.

The effects of extreme conditions on molecular solids

Welcome to this themed issue of CrystEngComm entitled: ‘The effects of extreme conditions on molecular solids’.

The effects of extremely hot summer 2010 on water temperature and oxygen distribution in Karelian lakes

Presented are the results of the analysis of interannual variability of the thermal regime of two Karelian lakes. The data of long-term observations in Lake Syamozero (1953–2011) and Lake Vendyurskoe (2007–2013) enabled analyzing and comparing the range of the natural interannual variability of water temperature and its values in hot summer 2010. Considered are the effects of extreme conditions in summer 2010 on the formation of thermal stratification and on the dissolved oxygen regime in the lakes. It is revealed that the global warming may increase the probability of deep anoxia development in shallow lakes in the temperate zone.

Water Budget on Various Land Use Areas Using NARR Reanalysis Data in Florida

1992 to 2002 data from North American Regional Reanalysis (NARR) were used to investigate water budget on five land use areas: urban, forest, agriculture, lake, and wetland in the state of Florida, USA. The data were evaluated based on the anomalies of rainfall, evaporation, and soil moisture from the average condition. The anomalies were used to investigate the effect of extreme conditions on water budget parameters for various land uses in both northeast and south of Florida. The results showed that extreme events such as La Niña strongly affected the water budget on land-use areas in both regions as the negative monthly rainfall anomalies were observed during the 1999-2000 event, while EI Niño and thunderstorms in summer caused positive rainfall anomalies with more than 70% in all study areas. Higher rainfall led to higher soil moisture anomalies for the agriculture, forest, and wetland from 1992 to May 1998 in both study regions. However, soil moisture becomes primary source for evaporation in drier conditions, and differences in capacity of plants access water, often dictated by the rooting depth, can result in contrasting evaporative losses across vegetation types. Hence, the forest, which had the deeper roots, had lower soil moisture anomalies, but higher evaporation anomalies than agriculture area during the drought event.

Polymeric fibre composites, basic types, principles of fabrication, and properties. Part 5. Effect of performance effects on polymeric fibre composites; safety/hazardousness characteristics

The principles of materials science of polymeric fibre composite materials (PFCM) containing different reinforcing fibrous fillers (short-cut fibres, paper, yarn, tow, sliver, fabrics, and nonwoven materials) and different matrices (thermoplasts and thermosets) are examined in an analytical review [Khim. Volokna, No. 4 and 5 (2005); No. 1, 4, and 6 (2006)]. The mutual effect and reaction of the components of PFCM fibres and matrices) are analyzed, information is reported on the fabrication and properties of different kinds of composites: fibre-filled molding materials, pertinaxes, textolites, unidirectional composites, honeycomb plastics, etc. New types of composites with ultrahigh mechanical and thermal characteristics are examined. Testing methods and the functional properties of PFCM are examined: mechanical, thermophysical, electrophysical, optical. The mechanisms of the changes in the structure and properties of PFCM under external effects: thermal, photochemical, ionizing radiation, active media, and other factors, are analyzed. Performance reliability indexes are examined, including aging and the effect of extreme conditions. Safety/hazardousness characteristics are very important in selection of PFCM and use of articles made from them: sanitary-hygienic and toxicological, combustibility and toxicity of products of combustion. The following features of polymeric fibre composites in comparison to other materials are summarized below based on the examination: — Combination of different kinds of fibre fillers and matrices (binders) allows regulating the properties of PCM in a wide range, selecting the optimum indexes for items with a wide spectrum of applications. — Items made of PFCM involve low specific consumption of materials and are easy to manufacture, process, and treat in comparison to many traditional materials, metals and ceramics in particular. — Articles made from composites are reliable in use, almost not subject to corrosion, and do not require special protection or periodic painting of the surface. — With respect to specific mass characteristics, PFCM can be many times better than items made of metals and other traditional materials. This is important for using them in vehicles, aircraft, rescue craft, and sporting goods. Due to the features of the properties and the positive performance characteristics, PFCM have a great future in the most varied areas of application.

Effect of Extreme Conditions On the Mechanical Properties of Wood Fiber-Polystyrene Composites. Ii. Sawdust as a Reinforcing Filler

Abstract The mechanical properties and dimensional stability of composites of polystyrene filled with sawdust of hardwood aspen and softwood spruce have been investigated under various extreme conditions, for example, exposure to water at room temperature for 14 days and at boiling temperature for 24 h, as well as heat exposure at ± 105°C for 5 days and at -20°C for 2 h. Mechanical properties improve due to the treatment of the composites with a coupling agent [e.g., 3% poly [methylene(polyphenyl isocyanate)] (PMPPIC)], or by using coated (10% polymer ± 8% PMPPIC) or grafted (styrene) fibers. the treated composites or treated fiber-filled composites also showed more dimensional stability compared to nontreated composites. In addition, mechanical properties improve due to the treatment of the composites under different extreme conditions compared to normal ones. From the experimental results, it is suggested that different compounding methods of preparation of composites play an important role in improving the mechanical properties of the wood fiber-filled thermoplastic composites, even under extreme conditions.

Comparison of Time Delay during In-Flight and Ground Simulation

An in-flight experiment was performed to investigate the effects of time delay on manual flight control and flying qualities. The experiment was conducted using the USAF/FDL variable-stability NT-33A aircraft. Pure time delay was added equally to the pitch and roll flight control system. Evaluation tasks were presented on a head-up display (HUD). Instrument meteorological conditions (IMC) were simulated which limited the visual cues available to the pilot to the 20 degree foveal scene provided by the HUD. The in-flight time delay data were generated with full fidelity, unlimited range of motion cues. Using the same cockpit and a digital aerodynamic simulation, the in-flight experiment was completely replicated as a fixed-based ground simulation. Thus, the effects of extreme conditions in motion cuing (i.e., full motion versus no-motion) were examined for constant visual cuing.

Use of grafted aspen fibers in thermoplastic composites: IV. Effect of extreme conditions on mechanical properties of polyethylene composites

AbstractHardwood fibers of aspen in the form of chemithermo‐mechanical pulp (CTMP) have been used as reinforcement in linear low density polyethylene (LLDPE). The effect of composite treatment (immersion in boiling water, heat exposure at 105°C for seven days or at a temperature of −40°C) on resulting mechanical properties were evaluated. The grafted aspen CTMP composites showed by far the best results with regard to secant modulus, tensile strength, energy, and strain when compared to those of wood flour, mica or glass–fiber filled LLDPE, as well as to virgin LLDPE. Finally, the dimensional stability of CTMP aspen‐filled LLDPE composites immersed for four hours in boiling water was better than that of mica or glass–fiber filled LLDPE.

Early prediction of corn yields from daily weather data and single predetermined seasonal constants

Since a large portion of year-to-year fluctuation in crop yields is due to weather variations, there have been many efforts to model crop—environment relationships and develop operational yield-prediction systems. However, this effort has been complicated by the fact that the end result (yield) is the summation of many diverse daily responses of plants to environmental factors. Further, most plant responses are not linear, therefore effects of extreme conditions are lost if daily weather variables are averaged over periods of days or weeks and then correlated with plant growth and/or development. The objective of this study was to quantify daily growth responses of maize ( Zea mays L.), determine generalized growth—environment relationships, and develop a yield-prediction system adapted to daily input of commonly published weather variables for large areas of production. Daily growth rates obtained in Illinois, Iowa and Minnesota (1978–1979), from measurements of leaf extension, were regressed on selected environmental variables to obtain a growth-prediction equation applicable to average temperature and rainfall data for areas such as crop reporting divisions. Daily values of the growth-prediction equation applied to recorded weather data from Iowa (by crop reporting divisions) for the period 1950–1973 were summed each year for 20, 40 and 60 days from the date 50% of the crop was planted (beginning date), to obtain growth indices for subsequent use in the analysis of growth—yield relationships. Recorded yields 1950–1973 (USDA) were regressed on: growth index, latitude, beginning date, running 15-day sum of maximum temperature, running 15-day sum of percent estimated soil moisture, sum of percent estimated soil moisture from beginning date to prediction, fertilizer applied (nitrogen); and various transformations of these seven basic variables. The prediction equation (specific for Iowa) obtained from this regression (along with the growth-prediction equation) applied to independent data for 1974-177, resulted in yield predictions a few days to a month earlier, and equal or better than the first CRB-SRS-USDA forecasts each year. To extend the system to other states the same procedure is applied for development of appropriate coefficients.