Energy Acquisition of Solar-Powered Joint-Wing Aircraft Considering Mismatch Power Loss

Solar-powered aircraft can perform long-term flights with clean solar energy. However, the energy derived from solar irradiation is influenced by the time of year and latitude, which limits the energy acquisition ability of solar aircraft with a straight-wing configuration. Hence, unconventional configurations based on increasing wing dihedral to track the sun are proposed to improve energy acquisition at high-latitude regions in winter, which may involve power loss caused by mismatch in the photovoltaic system. However, mismatch loss is seldom considered and may cause energy to be overestimated. In this paper, the energy acquisition characteristics of a joint-wing configuration are presented based on the simulation of an energy system to investigate the mismatch power loss. The results indicate a 4~15% deviation from the frequently used estimation method and show that the mismatch loss is influenced by the curved upper surface, the severity of shading and the circuit configuration. Then, the configuration energy acquisition factor is proposed to represent the energy acquisition ability of the joint-wing configuration. Finally, the matching between the aircraft configuration and flight trajectory is analyzed, demonstrating that the solar-powered aircraft with an unconventional wing configuration is more sensitive to the coupling between configuration and trajectory.

Research on Radio Frequency Energy Acquisition Technology Used in Partial Discharge Sensors

To solve the energy supply problem of distributed sensor nodes for power equipment condition monitoring, the radio frequency energy acquisition technology scheme and low power consumption control method suitable for this type of sensor are studied. In the research of radio frequency energy technology, a high-gain radio frequency receiving unit is designed to convert a specific frequency high-frequency spatial electromagnetic wave into a AC small signal, and a radio frequency-voltage doubler rectifier unit is designed to convert the AC small signal into a DC signal and boost it, a supporting energy management unit is designed to control the energy interaction with the back-end sensor and provide a reliable and stable DC voltage to the partial discharge sensor. In terms of low-power control, the hardware adopts frequency-reduction detection and low-power devices, and the software proposes a work mode switching strategy, forming an ultra-low power design and application scheme for partial discharge sensors.

Optimal Design of Antenna for Radio Frequency Energy Acquisition System

At present, many sensors are gradually developing in the direction of ultra-low power consumption, miniaturization, and low cost, which makes radio frequency energy acquisition technology a popular research field with a wide range of applications. However, traditional sensors are generally powered by batteries, which greatly increases the size of the device. Furthermore, antenna is an important module for radio frequency energy acquisition, and optimization of its sensitivity and other performance is particularly important. This article uses HFSS electromagnetic simulation software to simulate antenna elements and arrays made of PTFE, and simulates various parameters. And optimization, an antenna array element whose port impedance characteristics and unit antenna gain both meet the design requirements is constructed. Finally, the gain of the 2×2 array antenna after parameter optimization is 13.8dB, which greatly improves the gain of the receiving antenna.

The Fire

Societies need energy in order to sustain themselves and their members. This energy comes in two forms: fuel and food. These are continuous: they are both means of energy acquisition consumed for the same purpose, the maintenance of a complex society. The energy sources that sustain a society—whether fuel or food—must have a sufficiently high aggregate energy returned on energy invested (EROI). The EROI of a source is the energy acquired from a source divided by the energy that the society had to invest in acquiring it. Once the EROI of a society’s energy sources drops below a certain threshold, societal collapse often results: the breakup of that society and the emergence of new, simpler societies. Calculations suggest that maintenance of a society recognizably similar to our own vis-à-vis socioeconomic parameters requires energy sources with EROIs in the 11–14 range. Maintenance of certain markers of liberal democracies may require higher EROIs, in the 20–30 range.

Aging as a consequence of selection to reduce the environmental risk of dying

Each animal in the Darwinian theater is exposed to a number of abiotic and biotic risk factors causing mortality. Several of these risk factors are intimately associated with the act of energy acquisition as such and with the amount of reserve the organism has available from this acquisition for overcoming temporary distress. Because a considerable fraction of an individual’s lifetime energy acquisition is spent on somatic maintenance, there is a close link between energy expenditure on somatic maintenance and mortality risk. Here, we show, by simple life-history theory reasoning backed up by empirical cohort survivorship data, how reduction of mortality risk might be achieved by restraining allocation to somatic maintenance, which enhances lifetime fitness but results in aging. Our results predict the ubiquitous presence of senescent individuals in a highly diverse group of natural animal populations, which may display constant, increasing, or decreasing mortality with age. This suggests that allocation to somatic maintenance is primarily tuned to expected life span by stabilizing selection and is not necessarily traded against reproductive effort or other traits. Due to this ubiquitous strategy of modulating the somatic maintenance budget so as to increase fitness under natural conditions, it follows that individuals kept in protected environments with very low environmental mortality risk will have their expected life span primarily defined by somatic damage accumulation mechanisms laid down by natural selection in the wild.

An evolutionary explanation of female-biased sexual size dimorphism in North Sea plaice, Pleuronectes platessa L.

Sexual size dimorphism (SSD) is caused by differences in selection pressures and life-history tradeoffs faced by males and females. Proximate causes of SSD may involve sex-specific mortality, energy acqui-sition, and energy expenditure for maintenance, reproductive tissues, and reproductive behavior. Using a quantitative, individual-based, eco-genetic model parameterized for North Sea plaice, we explore the importance of these mechanisms for female-biased SSD, under which males are smaller and reach sexual maturity earlier than females (common among fish, but also arising in arthropods and mammals). We consider two mechanisms potentially serving as ultimate causes: (1) male investments into male repro-ductive behavior might detract energy resources that would otherwise be available for somatic growth, and (2) diminishing returns on male reproductive investments might lead to reduced energy acquisition. In general, both of these can bring about smaller male body sizes. We report the following findings. First, higher investments into male reproductive behavior alone cannot explain the North Sea plaice SSD. This is because such higher reproductive investments require increased energy acquisition, which would cause a delay in maturation, leading to male-biased SSD contrary to observations. When account-ing for the observed differential (lower) male mortality, maturation is postponed even further, leading to even larger males. Second, diminishing returns on male reproductive investments alone can qualitative-ly account for the North Sea plaice SSD, even though the quantitative match is imperfect. Third, both mechanisms can be reconciled with, and thus provide a mechanistic basis for, the previously advanced Ghiselin-Reiss hypothesis, according to which smaller males will evolve if their reproductive success is dominated by scramble competition for fertilizing females, as males would consequently invest more into reproduction than growth, potentially implying lower survival rates relaxing male-male competition. Fourth, a good quantitative fit is achieved by combining both mechanisms while accounting for costs males incur during spawning.