Experimental and numerical research on the effects of pressure and CO2 dilution on soot formation in laminar co-flow methane/air diffusion flames.

An experimental and numerical investigation was conducted to examine the formation of soot in methane/air laminar diffusion flames under varying CO2 dilution ratios, ranging from 0% to 40%, and pressures between 5 and 10 atm. The experimental methodology incorporated diffuse-light two-dimensional line-of-sight attenuation (diffuse 2D-LOSA) to ascertain the volume fraction and peak temperature distribution of soot within the flames. For the numerical methodology, CoFlame-an open-source computational code-was utilized to calculate the detailed flame temperature, soot volume fraction, and the mole fractions of key intermediate species pivotal to soot generation. The study reveals that an increased dilution ratio of CO2 can reduce flame temperature and the molar fraction of hydrogen (H), while simultaneously increasing the molar fraction of hydroxyl (OH). This shift in chemical composition results in a reduced rate of soot nucleation and an intensified oxidation process during the later stages of soot development, thereby diminishing the overall soot volume fraction. An increase in pressure significantly boosts the processes of soot nucleation, HACA surface growth, and PAH condensation, thereby promoting the formation of soot. Elevated pressure corresponds to an increase in flame temperature and a narrower soot formation region. Additionally, the inhibitory effect of CO2 dilution on soot formation is mitigated under increased pressure. The findings from this research are expected to provide valuable insights and strategic guidance for the management and control of pollutants in the context of hydrocarbon fuel combustion, particularly when CO2 dilution is employed.

Photodetector with a metalens packaging module for visible light communication based on RGBY illumination LED light source.

A novel, to the best of our knowledge, photodetector with a metalens packaging module used as the visible light communication (VLC) receiver is proposed and designed. An LED consisting of red, green, blue, and yellow chips (RGBY-LED) is adopted as the transmitter for intensity modulation direct detection VLC systems. A metalens array with a numerical aperture (NA) of 0.707 used as a polarization-insensitive planar lens of the VLC system receiver is designed at wavelengths of 457, 523, 592, and 623 nm corresponding to blue, green, yellow, and red for high efficiency. Compared with a traditional Fresnel lens positive-intrinsic-negative (PIN) photodetector module as the VLC receiver, the introduction of a metalens module can decrease the form factor of the VLC receiver module and, in particular, it is much thinner. The combination of the multi-color LED transmitter and photodetector metalens packaging module receiver can increase the modulation bandwidth due to four different wavelengths used for the VLC system. Finite-difference time domain (FDTD) simulations are performed to validate the performance of the photodetector with a metalens module. It is revealed that the corresponding efficiencies of 57.5%, 55.4%, 57%, and 56.3% were achieved at wavelengths of 623, 592, 523, and 457 nm, respectively, based on a metalens array with a 0.707 NA and 2.5 µm radius of the active area of the photodetector. It is a promising technology for indoor VLC systems such as those for smart phones and other Internet of Things devices due to the need for compact packaging for the receiver.

Removal of toluene via non-thermal plasma generated by applying rare-earth tungsten electrode and nanosecond pulsed power supply.

The objective of this investigation is to evaluate the characteristics associated with degradation of toluene through the utilization of non-thermal plasma (NTP) generated via application of a low-work-function electrode and nanosecond pulsed power supply. Initially, a comparative analysis is made between toluene removal efficiency utilizing the low-work-function electrode and that achieved with the conventional stainless-steel electrode. The outcomes demonstrate that NTP generated by the low-work-function electrode exhibits markedly superior removal efficiency for toluene in comparison to the stainless-steel electrode operating at the same voltage. Subsequently, the impacts of voltage, pulse frequency, and initial concentration of toluene on the removal efficiency and production of by-products are investigated. It is found that as the voltage and frequency increase, the removal efficiency also increases, and a maximum toluene removal efficiency of 87.2% is achieved at a voltage of 12,000 V and pulse frequency of 2000 Hz. The removal efficiency first increases and then decreases with increasing toluene initial concentration. The investigation also finds that energy yield is negatively correlated with voltage and pulse frequency and positively correlated with the initial concentration. Finally, the reaction products were subjected to quantitative analysis using GC-MS. Based on the analysis results, potential reaction pathways are inferred.

Chronic lead exposure prolongs the immature stages of brown-legged grain mite, Aleuroglyphus ovatus, in a long-term population study.

An important aspect of environmental pollution, lead contamination is a widespread problem in several ecosystems. The present study aimed to evaluate the potential effects of low concentration lead stress on the development and reproduction of Aleuroglyphus ovatus. They were fed with artificial diet containing four different concentrations of lead (12.5, 25, 50, and 100 mg/kg). The results showed that there were both accelerating effect of lead (at low concentrations), as well as retarding effects (at high concentrations) on the development of the mite, and lead stress significantly prolonged the immature stages of A. ovatus and this inhibitory effect was greater with greater lead concentrations. The immature stages in the L group were shorter than those in the S group. In the S and L groups, the oviposition periods were significantly longer in the treatments with lower lead concentrations than in the control, while they were significantly shorter in those treatments of higher lead concentrations. Age-specific survival rate (lx) started to decline earlier in the S group, whereas there were no differences between the L group and CK. Age-specific fecundity rate (mx) peaked earlier in the S group than in CK, while mx peaked later in L1 and L2 than in CK. The rm value and net reproduction rate (R0) of treated A. ovatus decreased with increasing lead concentrations. Lower lead concentrations could promote population expansion while higher concentrations could inhibit population size. These results confirmed the developmental effect of lead stress on A. ovatus, highlighting that heavy metal contamination has negative effects on organisms in their natural environment.

TRNSYS simulation study of the operational energy characteristics of a hot water supply system for the integrated design of solar coupled air source heat pumps.

To address the issues with solar water heating systems taking up a lot of space, unstable hot water supply, air source heat pumps susceptible to frost in the winter, and low energy efficiency. The TRNSYS tool is employed in this work to simulate a solar-coupled air source heat pump system. The heat pump operation is first investigated using the inverse Carnot cycle. The performance coefficient is then calculated by the second law of thermodynamics without considering the pipeline's pressure drop and heat loss. The output temperature of the hot water that the heat pump circulates is then determined. The daily hot water needs can be estimated roughly based on information about solar radiation. The heat balance equation for flat plate solar collectors was used to compute the intensity of solar diffused radiation. The Berlage calculation was used to determine the solar radiation received on the collector's surface. After a qualitative analysis of the heat from the heat source, the efficiency of the linked heat pump and the conventional air source heat pump was compared. Analyzing the water temperature change graph for each month's data reveals that the system can achieve 50 °C during the water supply time each month. The heat pump's annual energy consumption is 6252.01 kWh, while the system's annual energy consumption is 9100.47 kWh. The study findings may be used as a guide to improving the design and management of the whole system. In addition, they may improve the solar water supply system's performance.

High-precision mapping reveals rare N6-deoxyadenosine methylation in the mammalian genome.

N6-deoxyadenosine methylation (6mA) is the most widespread type of DNA modification in prokaryotes and is also abundantly distributed in some unicellular eukaryotes. However, 6mA levels are remarkably low in mammals. The lack of a precise and comprehensive mapping method has hindered more advanced investigations of 6mA. Here, we report a new method MM-seq (modification-induced mismatch sequencing) for genome-wide 6mA mapping based on a novel detection principle. We found that modified DNA bases are prone to form a local open region that allows capture by antibody, for example, via a DNA breathing or base-flipping mechanism. Specified endonuclease or exonuclease can recognize the antibody-stabilized mismatch-like structure and mark the exact modified sites for sequencing readout. Using this method, we examined the genomic positions of 6mA in bacteria (E. coli), green algae (C. reinhardtii), and mammalian cells (HEK239T, Huh7, and HeLa cells). In contrast to bacteria and green algae, human cells possess a very limited number of 6mA sites which are sporadically distributed across the genome of different cell types. After knocking out the RNA m6A methyltransferase METTL3 in mouse ES cells, 6mA becomes mostly diminished. Our results imply that rare 6mA in the mammalian genome is introduced by RNA m6A machinery via a non-targeted mechanism.

Effect of temperature on development and reproduction of the carmine spider mite, Tetranychus cinnabarinus (Acari: Tetranychiae), fed on cassava leaves.

The effect of five constant temperatures (16, 20, 24, 28 and 32 °C) on the development, survival and reproduction of Tetranychus cinnabarinus (Boisduval) [= Tetranychus urticae Koch (red form)] fed on cassava leaves was examined in the laboratory at 85% relative humidity. Development time of various immature stages decreased with increasing temperature, with total egg-to-adult development time varying from 27.7 to 6.7 days. The lower thermal threshold for development was 10.8 °C and the thermal constant from egg to adult was 142.4 degree-days. Pre- and post-oviposition period and female longevity all decreased as temperature increased. The longest oviposition period was observed at 20 °C with 20.4 days. Under different temperatures, mated females laid, on average, 1.0, 2.9, 4.7, 4.7 and 4.9 eggs per day, respectively. The maximum fecundity (81.5 eggs per female) was at 28 °C and the intrinsic rate of increase (r m ) was highest (0.25) at 32 °C. The results of this study indicate that T. cinnabarinus population could increase rapidly when cassava leaves serve as a food source. At the appropriate temperature T. cinnabarinus could seriously threaten growth of cassava.

Differential expression patterns of two delta-9-acyl-CoA desaturases in Thitarodes pui (Lepidoptera: Hepialidae) during different seasons and cold exposure.

Thitarodes pui larvae have a limited distribution in the Tibetan Plateau and are the host of a parasitic fungus, Ophiocordyceps sinensis. Low temperature is a main environmental stress. However, understanding of T. pui cold adaptation mechanisms is insufficient. Delta-9-acyl-CoA desaturase (D9D) is closely correlated with cold adaptation for many organisms. To further understand the cold adaptation processes in T. pui larvae, two D9Ds, TpdesatA and TpdesatB were sequenced, and expression patterns were investigated during different seasons and cold exposure (under 0°C) in the laboratory. The full lengths of two cDNAs are 1,290 bp and 1,603 bp, and the ORFs encode a polypeptide of 348 and 359 amino acids, respectively. Four transmembrane domains, three conserved histidine residues and five hydrophobic regions exist in these two sequences. The expression level of TpdesatA is up-regulated in the long-term cold exposure and negatively correlated with temperature in seasonal patterns. TpdesatB responds to cold temperature in short-term cold exposure and positively corresponds temporarily in seasonal expression. Two D9Ds may have different substrate specificities, TpdesatA tends to use C16:0 and C18:0 as substrate while TpdesatB prefers C18:0. In conclusion, TpdesatA may play a very important role in T. pui cold tolerance and TpdesatB regulates function in short-term cold exposure and content change of fatty acids in the body.

[The spectrogram characteristics of organic blue-emissive light-emitting excitated YAG : Ce phosphor].

It is demonstrated that the panchromatic luminescence devices with organic blue-emissive light-emitting was fabricated. This technique used down conversion, which was already popular in inorganic power LEDs to obtain white light emission. A blue OLED device with a configuration of ITO/2T-NATA (30 nm)/AND : TBPe (50 Wt%, 40 nm)/Alq3 (100 nm)/LiF(1 nm)/Al(100 nm) was prepared via vacuum deposition process, and then coated with YAG : Ce phosphor layers of different thicknesses to obtain a controllable and uniform shape while the CIE coordinates were fine tuned. This development not only decreased steps of technics and degree of difficulty, but also applied the mature technology of phosphor. The results showed that steady spectrogram was obtained in the devices with phosphor, with a best performance of a maximum luminance of 13 840 cd x m(-2) which was about 2 times of that of the devices without phosphor; a maximum current efficiency of 17.3 cd x A(-1) was increased more two times more than the devices without phosphor. The emission spectrum could be adjusted by varying the concentration and thickness of the phosphor layers. Absoulte spectrogram of devices was in direct proportion with different driving current corresponding.