Cycle Temperature Research Articles

Experimental Investigation on the Effect of TiO2 Nanoparticles Emulsion in Water on Emissions and Performance Characteristics of DI Diesel Engine

The world is presently confronted with the twin crisis of resource restriction and environmental degradation. The search for solutions that promise a harmonious correlation with sustainable development, energy conservation, efficiency, and environmental preservation has become highly important. The main purpose of innovative studies on fuel refinement and combustion engines is to improve fuel properties by adding fuel additives. In this study, the impact of Titanium dioxide, TiO2, nanoparticles solution blended with diesel fuel on the performance and emission characteristics of four-stroke combustion engine OM 364 EU III, manufactured by IDEM Co and licensed by Daimler Benz, has been investigated. The selection of TiO2 nanoparticles is based on the easy access in the market and the gap recognized; in previous literature, these nanoparticles were added to biodiesel or n-butanol blends. The proposed combined fuel in this study contains 2.5 ppm TiO2 nanoparticles dissolved in 1200 [ml] water and added to 60 [Lit] base diesel fuel. The results of the aforementioned combined fuel have been compared with the base diesel fuel. It has been observed that applying nano-additives improves the mechanical performance of the diesel engine, such as power, torque, brake-specific fuel consumption, and thermal efficiency. Moreover, soot, unburned hydrocarbons, and carbon monoxide have declined by 2.78%, 3.55%, and 3.32%, respectively, due to TiO2 nanoparticles' catalytic effect on fuel combustion. However, the amount of NOx has increased up to 3.09% because of the high cycle temperature.

Effect of Magnetite Concrete on Splitting Tensile Strength and Gamma Ray Shielding Performance Exposed to Repeated Heating at High Temperature

Radiation shielding concrete is one of the most used materials in the construction of nuclear power plants and will be subjected to high temperatures for a long time during its service life. This study aims to investigate deterioration of radiation shielding concrete with multiple heating at different temperatures. A microwave oven was used as a heating apparatus to simulate irradiation, and 200, 300, and 400 °C were selected as experimental cycle temperatures. The apparent characteristics, mass loss, splitting tensile strength, and gamma ray shielding properties of the commonly used magnetite shielding concrete were investigated. The results showed that the splitting tensile strength and gamma shielding performance of concrete were dramatically reduced at first heating. Then, as the heating times increased, the splitting tensile strength and gamma shielding properties of the concrete continued to deteriorate, and the higher the increase in heating temperature, the more severe the deterioration of the concrete. During the service period of radiation shielded concrete, the magnitude of temperature under the service conditions will affect the deterioration degree of concrete, and the continuous change of temperature will continuously lead to the deterioration of concrete.

Mechanism of Separation of Contaminants from Activated Carbon by Closed Cycle Temperature Swing Desorption

In this paper, the mechanism of separation of volatile organic compounds (VOCs) from activated carbon adsorption beds during closed cycle temperature swing desorption was studied. Toluene gas at different concentrations was used as the gas for closed cycle temperature swing desorption to regenerate activated carbon beds saturated with toluene. This research advances our understanding of the separation of contaminants from activated carbon and the mechanism of the process by which waste gas with a background concentration desorbs activated carbon in hot gas with a background concentration, establishing a technological foundation for the closed cycle temperature swing desorption process of activated carbon. When the background concentration was 2 g/m3, the average desorption rates of unit activated carbon at 10 cm in 40 min and 60 min were the largest, at 0.0099 and 0.0067 g/ (g•min), respectively. The fit of the Bangham desorption rate equation was the best. When the background concentration of toluene was 2 g/m3 and the filling length of the activated carbon layer was 10 cm, the desorption rate constant was the highest, at 0.0152 min−1.

Periodic reverse electrodeposition of (1 1 1)-oriented nanotwinned Cu in small damascene SiO2 vias

It is quite challenging to electrodeposit (111)-oriented nanotwinned Cu in small damascene SiO2 vias because of the existence of the sidewalls of the vias. However, by tailoring electroplating waveforms and temperatures, one can overcome this difficulty. Fine pitch nanotwinned Cu (NT-Cu) with high ratio of (111) surface grains were fabricated using periodic reverse (PR) electrodeposition in damascene SiO2 vias. The PR electroplating parameters for via-filling were adjusted by tuning duty cycle and electrolyte temperatures. The PR current may remove randomly oriented nuclei caused by the sidewall-growing front. Thus, the bottom-up filling of the highly (111)-oriented NT-Cu was achieved. (111) surface ratios greater than 85% and 50% were obtained in 10-µm and 2-µm vias in diameter, respectively. Besides, a mathematical model was proposed to predict the (111) surface ratio of the ultra-fine pitch vias fabricated by PR electrodeposition. This investigation offers a new route to the development of NT-Cu interconnects for ultra-fine pitch packaging.

Continuous Phase Change Materials for Power Generation from Daily Air Temperature Cycles

AbstractPower generators that convert daily air temperature cycles to electricity should have both high power output and wide operating temperature range. Herein, a power generator combining a thermoelectric device and a mixture of various encapsulated alkanes that undergo continuous phase transitions induced by ambient temperature cycles is demonstrated. The operating temperature range of such a power generator can be extended by selecting appropriate alkane capsules to be incorporated into the device. A power generator with an operating temperature range of −0.2–37.2 °C is demonstrated; this operating temperature range is obtained when the temperature difference between the highest and lowest temperatures of the ambient temperature cycle is 14.2 °C, which is the equivalent environment in a Stevenson screen outdoors. The wide operating temperature range would permit power generation from daily temperature variations in many temperate and subtropical countries. The electric powers obtained by this power generator when placed in an indoor room and an outdoor Stevenson screen are 180 and 300 µW, respectively. Our temperature cycle‐based power generators pave the way for power sources that can generate electricity semi‐permanently in a broad range of environment.

Mimicking seasonal changes in light-dark cycle and ambient temperature modulates gut microbiome in mice under the same dietary regimen.

To better adapt to seasonal environmental changes, physiological processes and behaviors are regulated seasonally. The gut microbiome interacts with the physiology, behavior, and even the diseases of host animals, including humans and livestock. Seasonal changes in gut microbiome composition have been reported in several species under natural environments. Dietary content significantly affects the composition of the microbiome, and, in the natural environment, the diet varies between different seasons. Therefore, understanding the seasonal regulatory mechanisms of the gut microbiome is important for understanding the seasonal adaptation strategies of animals. Herein, we examined the effects of changing day length and temperature, which mimic summer and winter conditions, on the gut microbiome of laboratory mice. Principal coordinate analysis and analysis of the composition of microbiomes of 16S rRNA sequencing data demonstrated that the microbiomes of the cecum and large intestine showed significant differences between summer and winter mimicking conditions. Similar to previous studies, a daily rhythm was observed in the composition of the microbiome. Furthermore, the phylogenetic investigation of communities by reconstruction of unobserved states predicted seasonal changes in several metabolic pathways. Changing day length and temperature can affect the composition of the gut microbiome without changing dietary contents.

Synergistic multi-source ambient RF and thermal energy harvester for green IoT applications

In a future green Internet of Things (IoT) reality, billions of devices of the IoT infrastructure should be self-powered. Harvesting ambient energy to power IoT devices is an attractive solution that can extend battery life or can completely replace batteries. Considering the global applications of IoT, ubiquitous and continuous availability is an important requirement for ambient energy sources. Radio frequency (RF) energy from mobile phone towers and thermal energy from diurnal cycle temperature fluctuations are good candidates. In this study, we present a synergistic multi-source energy harvester (MSEH) comprising an RF energy harvester (RFEH) and a thermal energy harvester (TEH) integrated through a dual-function component, heatsink antenna. Both harvesters collect ambient energy 24 h a day and are not location specific. The TEH, which is in the shape of a box, collects energy using heatsinks on its sidewalls. The same heatsinks are optimized to also serve as receiving antennas of the RFEH, which collects energy from the GSM900, GSM1800, and 3G bands. Due to the synergistic integration, radiation efficiency of the antenna doubled from 40% to 80% which resulted in ∼10% increase in power conversion efficiency of the RFEH. Similarly, the average power of the TEH without heatsinks 120 μW is doubled to 240 μW for TEH with heatsinks. Field tests have shown that the outputs of the TEH and RFEH have increased 4 and 3 times compared to the independent TEH and RFEH respectively. A temperature and humidity sensor based IoT node has been successfully powered through this energy harvesting system. Overall, the MSEH can collect 3680 μWh of energy per day which is sufficient to obtain the sensors data with a time interval of 3.5 s.

Effect of Acrylamide And Potassium Peroxodisulphate on The Quality of Bead Gel Based on Cassava Bagasse-Carrageenan Using Microwave Grafting Method

Hydrogels are widely used for drug delivery systems, immuno-chemotherapy applications, efficient use of water, preventing dry soil, and increasing soil infiltration. Generally, hydrogels are derived from synthetic polymers which is non-biodegradable and toxic. Cassava bagasse is an alternative cellulose to make hydrogels. The purpose of this research was to determine the effect of the amount of acrylamide and potassium peroxodisulphate (KPS) initiator on the quality of bead gel based on cassava bagasse-carrageenan. Chemical structure of the hydrogel was studied using FTIR spectroscopy. Cassava bagasse was immersed in a solution of n-hexane to separate the fat. Then, fat-free cassava bagasse was grafted with mass ratios of cassava and acrylamide 1:5, 1:10, and 1:15 in 110 mL water. The solution was added with a KPS initiator with weight variations (g) 0.04; 0.08; 0.12 then stirred 15 min. The solution was put in the microwave with 630 watts of irradiation for 450 s with the cooling cycle temperature maintained at 65-70<sup>o</sup>C. The aqueous of grafted polymer and carrageenan was injected into beaker glass that contained 1 cm of palm oil and mixture of 0.2 M CaCl<sub>2</sub> and 0.2 M KCl in an ice bath. Results showed that the highest average swelling capacity was found in the bead gel variation 1:15 with the number of initiators 0.04 g of 1797.95% at a time of 210 minutes of immersion. From FTIR spectrum, it was found that there was a success in grafting acrylamide into bagasse’s backbone using the microwave grafting method with KPS as initiator.

Study of recirculating water-based and carbon-based working fluids on the combustion flow field and the cycle performances of semi-closed CO2-capturing Brayton-derived cycles

• A performance analysis was performed in CO 2 and H 2 O recycling cycles. • A CFD combustion study was performed in H 2 O and CO 2 representative conditions. • An economic analysis was performed in CO 2 and H 2 O recycling cycles. • CO 2 fluids give better cycle performances and H 2 O better combustion temperature fields. The transition into new power technologies that utilize fossil fuels with near zero emissions to the ambient is an urgent need to mitigate the worldwide environmental problems. In this study, detailed analyses of carbon-based and water-based oxy-combustion power cycles are introduced. The applied methodologies to perform these analyses comprise CFD analysis of reacting flows for dual recuperative cycle (DRC) and reheated cycle (RHC). The employed CFD methodologies used the non-simplified Navier-Stokes formulation of reacting flows to avoid the use of extra models or assumptions. It was found that recycling carbon-based fluids would allow better overall performances of the resulting cycles. Recycling water-based fluids, however, would provide some interesting features regarding the temperature field in the combustion chamber. Hence, it would avoid in a better way the possibility of facing overheating caused by oxy-combustion, as well as provide some valuable aerodynamic features for the turbines. When analyzing the obtained combustion flow field, CO 2 and H 2 O working fluids create a more important temperature abatement in the flame surrounding areas and trail than Air. When comparing CO 2 and H 2 O working fluids between them, the H 2 O working fluid initially showed a slightly bigger high-temperature zone than the CO 2 working fluid. Despite this fact, and after those initial zones, the H 2 O working fluid showed a more important temperature abatement than the CO 2 working fluid, except for the transversal tip of the flame trail, where temperatures are in a safe range for superalloys. When considering the temperature on the fluid domain symmetry axis and at the outlet, for the 30 atm case (30.4 bar), it was found that the CO 2 fluid presented a temperature equal to 86.9% of the Air one in the same location and pressure, whereas the H 2 O fluid presented an 82% of the Air one. In addition, thermoeconomic analyses were conducted for the DRC and RHC that are working at high pressure of less than 42 bar and operating temperatures of 1100 K to 1450 K to ensure feasible design for the cycle components. Furthermore, it is found that a maximum efficiency of 47.50% is obtained by the carbon-based RHC under wet-cooling conditions and a minimum cycle efficiency of 33.54% is obtained by the water-based DRC under dry-cooling conditions. From an economic point of view, the average LCOE of the present carbon-based and water-based cycles is 4.17 ¢/kWh, which is 28% lower than the average LCOE of the supercritical carbon-based and integrated gas-turbine-based cycles. Moreover, the LCOE of the carbon-based RHC is minimum (3.92 ¢/kWh) at minimum cycle temperature (T min ) of 305 K (wet cooling) and identical to the water-based RHC (4.00 ¢/kWh) at T min of 323 K (dry-cooling).

Покращення показників автомобільних дизельних двигунів при додаванні водневої каталітичної добавки

The aim of the study is to present a new proposed method for improving the efficiency of transportation diesel engines. Considering the rising cost of transportation, where 80% of the expenses are attributed to fuel costs, there is a necessity to develop methods for reducing fuel consumption. Among the main approaches are the use of alternative fuels or fuel additives. One of the most effective and promising options is the utilization of hydrogen, both as an alternative fuel and a fuel additive. Among the crucial factors significantly influencing the efficiency of hydrogen additives is the method of their delivery to the internal combustion engine. Injecting hydrogen during the engine's intake stroke, although a simple method, faces challenges in achieving precise engine control and poses risks due to the potential formation of an explosive mixture in the intake tract and subsequent ignition. A proposed solution involves introducing small hydrogen additives into the high-pressure fuel line, between the fuel pump and the injector. After the completion of the injection process in the high-pressure line, a "rarefaction wave" is generated. Utilizing this effect allows introducing a small amount of hydrogen into the diesel fuel. Hydrogen delivery is ensured by a special device equipped with a check valve that reacts to changes in pressure in the fuel line. Hydrogen, when introduced into the fuel, promotes improved combustion and increased engine efficiency. This results in a reduction in fuel consumption by 0.4 to 3.5% compared to nominal values, with particularly high fuel efficiency observed at partial load conditions, as well as during acceleration and maneuvers. It is worth noting the positive environmental impact of this technology. When adding hydrogen in a proportion of 0.1% of the fuel mass, a decrease in hydrocarbon emissions by 40–50% and carbon monoxide by 15–25% is observed. However, an increase in nitrogen oxide emissions by 3–7% has been identified, which is associated with a certain elevation of the maximum cycle temperature. Nevertheless, NOx emissions increase can be mitigated by implementing appropriate adjustments to the engine's operating parameters.

Is there a link between the length of the solar cycle and Earth’s temperature?

The Sun provides most of external energy to Earth’s system and thus has the potential of influencing it. Various studies reported a correlation between the solar cycle length and the northern hemisphere temperatures on Earth. Here, we reassess the cycle length record by incorporating the newly revised and updated sunspot number series as well as plage area composite, before comparing it to Earth temperature records. We find that cycle length series constructed from sunspot and plage data exhibit the same behaviour, both showing a downward trend after 1940. Our results suggest that the agreement between solar cycle lengths and temperatures found earlier is an artefact of (1) some arbitrary choices made by those studies when constructing the cycle length series as well as (2) a rather short time interval, to which the analyses were restricted. When considering the entire period of reliable sunspot and temperature data, these records diverge before about 1870 and after 1960. We also find a poor agreement between Earth temperatures and cycle length when using plage areas instead of sunspot data to derive cycle lengths. Our result of the divergence between cycle length series and Earth’s temperature after 1960 implies that the cycle length cannot be used to support a solar origin for the warming on Earth over the last 5 decades.

Process knowledge inspired opportunistic approach for thermodynamically feasible and efficient design of hydrogen liquefaction process

Hydrogen (H2) liquefaction process is one of the complex processes because of the highly non-linear interaction between design variables and objective function. Finding a feasible design for such a complex process is challenging. Knowledge of refrigerant selection, composition, cycle temperatures, and compression ratio is essential in finding this feasible design. This study presents a simple, yet efficient approach inspired by process knowledge, known as knowledge-based optimization (KBO), to selecting an optimal mixed refrigerant (MR) composition and studying the effect of each refrigerant on the performance of the H2 liquefaction process. The infeasible design shows approach temperature (i.e., MITA) values as −33.5 °C, −4.0 °C, and −11.65 °C. The design variables' values are adjusted based on the KBO approach to keep the MITA value in the range of 1–2 °C. The share of each MR component in optimal case is 17% C1, 5% C2, 70% C3, 8% N2 in precooling, 9% C1, 80% N2, 11% H2 in cooling and 85% H2, 15% He in liquefaction cycle. Further, the KBO approach guides in selecting the lower and upper limit of each refrigerant based on their impact inside heat exchangers. Additionally, the heat flow behavior of H2 streams is analyzed for adiabatic and isothermal ortho-to-para reactors. This study will help process engineers and engineering practitioners to develop an energy-efficient and cost-effective initial design for the H2 liquefaction process.

The Influence of Condenser Temperature on the Energy and Exergy Efficiencies of the ORC

From low-grade heat sources, the organic Rankine cycle may be exploited to create power. The thermal efficiency of the organic Rankine cycle is affected by the value of the lowest cycle temperature, which is the condensation temperature. This study looks at the effect of condensation temperature on the efficiency of energy systems that use organic Rankine cycles. At a condensing temperature of 10–20 °C, the ORC thermal efficiency is calculated. R134a working fluid was used in the study. The expander's power output was boosted to 0.09765 kW by decreasing the condensing temperature. Additionally, the thermal efficiency has been enhanced by 3.826 %. At a minimum temperature of 10 °C, the expander speed at 595 rpm. Exergy efficiency has an 18.26 %. is shown that lowering the condensing temperature increased the ORC system's thermal efficiency and energy output.

Improving the Performance Properties of Eutectoid Steel Products by a Complex Effect

This study focuses on the assessment of possible hypereutectoid steel carbide mesh crushing. It is used for tools production, including forming rolls of various diameters, with modification and cyclic heat treatment methods. For steel containing 1.79-1.83% C, we studied the effect of 0.35-1.15% Si on the possible crushing of the cementite mesh within crystallization by introducing modifiers Ti, V, N, as well as simultaneously modifying V with N and Ti with N. The obtained castings of Ø200 mm, 400 mm high were cut into discs, from which we made samples for tests on wear, determining mechanical properties, thermal resistance, and susceptibility to brittle fracture. The assessment was performed in the as-cast and after double and triple normalizing and annealing with drawback. With additional fans blowing, we changed the cooling rate from 25 °C/h to 100-150 °C/h. We performed the microstructure analyses using traditional metallographic, micro-X-ray spectral analyses, and also used the segmentation process based on 2D image markers. It was found that the as-cast modifying additives infusion is insufficient for carbide mesh crushing. It can be made by multi-stage normalizing with accelerated cool-down for products up to 600 mm in diameter to cycle temperatures above the steel transfer from a plastic to elastic state (above 450 °C).

Investigation of thermal efficiency for subcritical ORC and TFC using super dry working fluids

AbstractEfficiency is a crucial factor for power cycles. Generally, in the same temperature range, the cycle efficiency for a basic organic Rankine cycle (ORC) is higher than a similar trilateral flash cycle (TFC) for almost all working fluids and heat source/heat sink temperature pairs. According to some recent results, by using super dry working fluids, the thermal efficiency of TFC can outperform its ORC counterpart at high temperatures. This study performed the thermodynamics analysis using three dry working fluids with subcritical basic ORC and TFC with zero to partial recuperated heat ratio. The results showed that using recuperative heat exchange effectively contributes to increasing the efficiency of ORC and TFC. However, the rate of efficiency increase in ORC is higher than the TFC, which can be clearly seen, especially at high maximal cycle temperatures. Using super dry working fluids, the recuperator‐free TFC has favorable cycle efficiency at high heat source temperatures. In contrast, by adding heat recovery for both systems, the ORC can outperform the TFC at 0.4, 0.2, and 0.1 recuperated heat effectiveness for Dodecane, Decane, and Nonane, respectively.

Three-Dimensional Metal-Insulator-Metal Decoupling Capacitors with Optimized ZrO2 ALD Properties for Improved Electrical and Reliability Parameters

Embedded three-dimensional (3-D) metal-insulator-metal (MIM) decoupling capacitors with high-κ dielectric films of high capacitance and long-life time are increasingly needed on integrated chips. Towards achieving better electrical performance, there is a need for investigation into the influence of the variation in atomic layer deposition (ALD) parameters used for thin high-κ dielectric films (10 nm) made of Al2O3-doped ZrO2. This variation should always be related to the structural uniformity, the electrical characteristics, and the electrical reliability of the capacitors. This paper discusses the influence of different Zr precursor pulse times per ALD cycle and deposition temperatures (283 °C/556 K and 303 °C/576 K) with respect to the capacitance density (C-V), voltage linearity and leakage current density (I-V). Moreover, the dielectric breakdown and TDDB characteristics are evaluated under a wide range of temperatures (223-423 K).

Collapse Limit of Thermally Treated Line Pipe Under Combined External Pressure and Bending Deformation

Abstract This study discusses the collapse criteria for thermally treated line pipe and their bending interaction against collapse based on a full-scale test under external pressure with and without bending loading. The critical collapse strain in the pressure bending test was much higher than that estimated by the DNV-ST-F101 standard because it was calculated based on estimating collapse pressures without bending interaction based on specified minimum yield stress (SMYS) of design pipe in the standard. However, the collapse pressures without bending interaction in full-scale test was significantly higher than that of the estimation according to DNV-ST-F101 standard. The effect of the thermal heat cycle simulated anti-corrosion coating heating on line pipe collapse criteria is also discussed based on the change of yield stress of pre-strained and thermally treated material. As the maximum heat cycle temperature increases, the reduction of the compressive yield stress along circumferential direction by the Baushinger effect due to UOE process (U: U-ing, cold forming from a plate; O: O-ing, cold forming from the U shape; E: cold expansion to meet geometric tolerances) becomes small. It is thought that a DNV equation for estimating the critical bending strain to collapse will provide a more accurate estimation of the critical collapse pressure and strain for thermally treated line pipe when the collapse pressure is calculated considering the change of strength parameters due to the tensile pre-strain level and heat cycle temperature.

IMPROVMENT OF ENVIRONMENTAL PERFORMANCE TWO-STROKE DIESEL DURING OPERATION

The development of world shipping is taking place in the context of ever-increasing requirements to reduce the concentrations of toxic components of gaseous combustion products of hydrocarbon fuels. Concentration limits for these substances are regulated in accordance with Appendix VI of the MARPOL 73/78 Convention. Among the controlled components of diesel exhaust gases, nitrogen oxides are the most dangerous for humans and environment. However, a decrease in the content of nitrogen oxides is inevitably associated with limitations on the maximum cycle temperature, that is, thermal efficiency, and hence with a deterioration in the fuel efficiency of the engine. At the moment, in order to reduce emissions of nitrogen oxides by large transport diesel engines, the most widely used is the recirculation of exhaust gases into the air receiver. A significant disadvantage of using this scheme is the need for cooling the exhaust gases and their additional purification, which leads to an increase in the weight and size characteristics of the system and to its rise in price. Therefore, to reduce its cost, it seems logical to combine exhaust gas recirculation with other ways to reduce nitrogen oxide emissions. For engines in operation, one of these methods is to change the angle of fuel injection. It can be assumed that the later the fuel is injected into the cylinder, the lower the temperature of the air charge will be and, accordingly, the lower the maximum combustion temperature, and hence the amount of nitrogen oxides. The calculation of nitrogen oxide emissions was simulated for the main engine MAN-B&W 7S50MC-C installed on the vessel "LILA SHANGHAI". Initially, the model created using the AVL-BOOST package was verified based on the available indexing results. After verification, the calculation of emissions of nitrogen oxides NOx was made with a variation in the angle of the start of fuel combustion at the nominal mode. The composition of the gases in the receiver was taken unchanged. As the fuel combustion start angle shifted further from the TDC, deterioration in fuel efficiency and a drop in cylinder power were observed, while reducing the mass of emitted nitrogen oxides NOx. However, it can be said that the environmental friendliness of an engine improves much faster than its fuel and power characteristics deteriorate. The above calculations show that for engines already in operation, changing the fuel injection angle makes it possible to reduce nitrogen oxide emissions. Therefore, this approach can be combined without much difficulty with other methods, thus reducing the cost of environmental improvement of the engine.

Ecology of Powdery Mildews – Influence of Abiotic Factors on their Development and Epidemiology

Powdery mildews are some of the most common and dangerous biotrophic plant pathogens. They attack more than 10, 000 plant species, and can be found mainly in temperate and sub-tropical zones. This review evaluates the effects of most important abiotic conditions on powdery mildew namely temperature, humidity, light quality, air composition (mainly CO2 and ozone concentration) and movement. With the most intensively studied factors, temperature and humidity, powdery mildew species vary in their requirements, this variation occurring in different phases of their life cycle. Generally, temperatures between 13 and 30 °C were optimal for their development, with conidial germination being the least and sporulation the most affected part of the life cycle and lower marginal temperatures only prolonging the latent period. The role of moisture in their development is more elusive; free moisture inhibits dispersal and germination of conidia and extension of hyphae of most powdery mildews. However, for further development high relative humidity is preferred and free water is required for release and dispersal of ascospores. Light most affects the pathogen indirectly through its effect on the host. Although germination and appressorial maturation is possible under low illumination and darkness, light is needed for completion of the disease cycle. A suitable photoperiod (alternating day and night) favors optimal development, e.g., continuous light reduces infection. The effect of CO2 concentration is complex; sometimes an increased concentration of CO2 causes more intensive disease, sometimes less or no effect at all. Most environmental factors also affect the host thus affecting the pathogen indirectly; other factors (e.g. UV or CO2) mainly directly affect the pathogen. Hypotheses on the possible effect of predicted climate change on pathosystems are discussed.

Dynamical modeling and coordinated control design of a multimodular nuclear power-hydrogen cogeneration plant

Based on the idea of interconnecting the modular high temperature gas-cooled reactor (mHTGR), steam Rankine cycle, Cu-Cl cycle and high temperature electrolysis (HTE), the schematic design of a multimodular nuclear power-hydrogen cogeneration is proposed. This cogeneration plant can be utilized to balance the net load by redistributing the motive steam between power generation and hydrogen production. The operational flexibility provided by steam redistribution relies heavily on plant-wide coordinated control. Since dynamic modeling is a crucial basis of control design, a lumped-parameter dynamic model of this nuclear cogeneration plant (NCP) is developed and implemented as a numerical simulation program. The steady-state modeling results show that the rated thermal power of this NCP is about 1523 MW, and the maximal values of hydrogen production rate and output electric power are 11.76 metric tons per hour and 647.3 MW, respectively. The open-loop transient analysis shows that the model's dynamic behavior is in good accordance with physical mechanisms. Further, a hierarchical coordinated control scheme is designed for this NCP, providing a load-following control function based upon steam redistribution, and the corresponding validations are also given. For the load decreasing with ramp rate at 8 MW/min and amplitude of 540 MW, the control system guarantees the grid frequency deviation is smaller than 0.2 Hz while the reactor thermal power, as well as the temperatures and pressures of hydrogen production reactions, are maintained around their expected values. The results in this paper show that the mHTGR-based power-hydrogen cogeneration plant is not only a clean source of electricity and hydrogen but also a flexible source for grid frequency stabilization.