Low Radiation Intensity Research Articles

Increasing the Efficiency of Ecological Solar Panels Combined with the Building’s Roof

This article is devoted to increasing the efficiency of ecological solar panels with their combination with the house’s roof. A solar panel construction that combines both the solar collector and the building cover is considered. This work investigates the efficiency of solar panels depending on the type of coating, heat-carrying medium mass flow rate, tube diameter, and the distance between the tubes. Among the coatings, Grafplast PDA roofing material is the most effective. Prandelli/Tuborama tubes with a diameter of 16 mm are recommended. The diameter of the tubes significantly affects the efficiency of the solar panel only at low intensity of solar radiation.

Impact of surface ultraviolet radiation intensity on hospital admissions for ischemic and hemorrhagic stroke: A large-scale database study using distributed lag nonlinear analysis, 2015-2022, in Harbin, China

ObjectivesOur aim is to evaluate the impact of surface ultraviolet radiation intensity on hospital admissions for stroke and to compare the correlation and differences among different subtypes of strokes. Materials and methodsWe collected daily data on surface ultraviolet radiation intensity, temperature, air pollution, and hospital admissions for stroke in Harbin from 2015 to 2022. Using a distributed lag non-linear model, we determined the correlation between daily surface ultraviolet radiation intensity and the stroke admission rate. Relative risks (RR) with 95% confidence intervals (CI) and attributable fractions (AF) with 95% CI were calculated based on stroke subtypes, gender, and age groups. ResultsA total of 132,952 hospitalized stroke cases (including hemorrhagic and ischemic strokes) were included in the study. We assessed the non-linear effects of ultraviolet intensity on hospitalized patients with ischemic and hemorrhagic strokes. Compared to the maximum morbidity benchmark ultraviolet intensity (19.2 × 10^5 for ischemic stroke and 20.25 for hemorrhagic stroke), over the 0-10 day lag period, the RR for extreme low radiation (1st percentile) was 0.86 (95% CI: 0.77, 0.96), and the RR for extreme high radiation (99th percentile) was 0.86 (95% CI: 0.77, 0.96). In summary, -4.842% (95% CI: -7.721%, -2.167%) and -1.668% (95% CI: -3.061%, -0.33%) of ischemic strokes were attributed to extreme low radiation intensity with a lag of 0 to 10 days and extreme high radiation intensity with a lag of 0 to 5 days, respectively. The reduction in stroke hospitalization rates due to low or high ultraviolet intensity was more pronounced in females and younger individuals compared to males and older individuals. None of the mentioned ultraviolet intensity intensities and lag days had a statistically significant impact on hemorrhagic stroke. ConclusionsOur study fundamentally suggests that both lower and higher levels of surface ultraviolet radiation intensity in Harbin, China, contribute to a reduced incidence of ischemic stroke, with this effect lasting approximately 10 days. This finding holds significant potential for public health and clinical relevance.

Rheological and microscopic characterization and correlation analysis of asphalt under high-intensity ultraviolet radiation

The lower radiation intensity (2–20 W/m2) was widely used for asphalt ultraviolet (UV) aging. The effect of high-intensity radiation on asphalt properties and microscopic morphology is unknown. This study investigated the rheological behavior, microscopic characterization, and correlation analysis of SBS modified asphalt under high-intensity UV radiation. Rheological properties tests encompassed temperature sweep (TS), multiple stress creep recovery (MSCR), and frequency sweep (FS). Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Gel Permeation Chromatography (GPC) tests were performed to reveal the microscopic characterization. In the early stages of UV aging, the rutting factor of asphalt was increased. The increment decreased as the UV aging time increased. The UV aging process did not alter the temperature sensitivity of asphalt. The complex shear modulus was influenced by UV radiation duration and loading frequency. Extended exposure to high-intensity UV radiation resulted in the formation of microcracks on the surface of the asphalt. The maximum molecular weight of the UV-aged asphalt was higher than that of the original asphalt. The degraded SBS modifier deteriorated the homogeneity of asphalt. The sulfoxide aging index, carbonyl aging index, number-average molecular weight (Mn), weight average molecular weight (Mw), and polymer dispersity index (PDI) presented a better correlation with rheological behavior indexes. The correlation between small molecule size (SMS), medium molecule size (MMS), and large molecule size (LMS) with rutting factor and complex shear modulus was poor. It was worth mentioning that the correlation between the MSCR test results and microscopic performance indicators was the best. Especially for the recovery rate and Jnr at 3.2 kPa, the mean absolute value of the correlation coefficient was 0.953.

Daily Light Integral, but Not the Photoperiod, Influences the Time to Flower and Finished Quality of Dianthus Specialty Cut Flowers

Because of the burgeoning year-round demand, greenhouse growers across the United States are increasingly becoming interested in producing specialty cut flowers for local and regional markets. However, outdoor or high tunnel production is not possible year-round in northern latitudes because of low temperatures and radiation intensities experienced during the winter and early spring. Additionally, natural short days in these seasons can limit which photoperiodic crops can be grown. Thus, our objectives were to quantify the influence of the photoperiod and daily light integral (DLI) on greenhouse-grown dianthus ‘Amazon Neon Cherry’ and ‘Amazon Rose Magic’ (Dianthus barbatus interspecific) cut flowers during the young plant and finishing stages. Seeds of both cultivars were sown under 9-, 10-, 11-, 12-, 13-, 15-, or 16-hour photoperiods and a DLI of either ≈5 or 10 mol⋅m−2⋅d−1. After 4 weeks, seedlings from several young-plant photoperiods were distributed across 11-, 12-, 13-, 14-, 15-, or 16-hour photoperiods or a 4-hour night interruption (NI) under a DLI of either ≈5 (low) or 14 (moderate) mol⋅m−2⋅d−1 for finishing. The young plant photoperiod generally had a statistical, but not commercial, influence on development and finished cut flower quality, whereas a 16-h finishing photoperiod marginally hastened development compared with an 11-hour finishing photoperiod. Additionally, stems were 11 to 13 cm longer when finished under the 16-hour photoperiod compared with those finished under the 11-hour photoperiod. Day length minimally influenced the time to flower and harvest, indicating a day-neutral flowering response. However, plants finished under a moderate DLI reached visible flower bud and were harvestable 9 to 10 days earlier than those finished under a low DLI. Additionally, ≈99% of cut flowers finished under a moderate DLI were harvestable, whereas only up to 32% and 57% of dianthus ‘Amazon Rose Magic’ and ‘Amazon Neon Cherry’, respectively, finished under a low DLI were harvestable. Although finished stem lengths were comparable between DLI treatments, cut flower stems were up to 29.6% thicker under a moderate DLI. These findings indicate that high-quality greenhouse-grown dianthus ‘Amazon Neon Cherry’ and ‘Amazon Rose Magic’ cut flowers can be produced when grown under any photoperiod between 9 and 16 hours for 4 weeks (during the young plant stage) and finished under any photoperiod between 11 and 16 hours or a 4-hour NI during finishing. If longer stems are desired, then plants can be finished under a 16-hour photoperiod. Young plants should be grown under a moderate DLI ≥10 mol⋅m−2⋅d−1 to promote biomass accumulation and reduce the young plant crop time. Additionally, plants should be finished under a moderate DLI ≥14 mol⋅m−2⋅d−1 to reduce crop time and increase stem thickness and yield.

Study on the spectrum model of light response of Manglietia yuyuanensis

Abstract To study the spectral characteristics of the photosynthetic response of Manglietia yuyuanensis, this paper uses a self-developed monochromatic light generator to generate 22 kinds of monochromatic light, and measures the net photosynthetic rate of Manglietia yuyuanensis under the irradiation of 22 kinds of monochromatic light, then obtains its light response curve under different wavelengths. The right-angle hyperbolic correction model was used to fit the light response curves under each kind of monochromatic light, and the completed spectrum of the light saturation points of Manglietia yuyuanensis was obtained. It makes up for the disadvantage that the self-developed monochromatic light generator cannot detect the light saturation point of the plant under some monochromatic light due to the low radiation intensity. This paper supposes that the coefficients α, β, γ, and Rd in the right-angle hyperbolic correction model are functions related to the wavelength λ, then fits a Gaussian function of α, β, γ, and Rd to wavelength λ. From the fitting results, the fitting degree of α, β, and γ can reach 0.8 or more, which indicates the fitting effect is good. The fitting degree of Rd is about 0.5. According to the fitting function, a new photosynthesis model related to wavelength and light radiation was obtained, and the fitting degree of the data by the new model is good, laying a foundation for future research on photosynthetic response curves of other plants.

Ghost polarimetry with a spatial light modulator for creation of structured illumination patterns

Subject of study. The spatial distribution of polarization properties for objects with linear dichroism is studied. Aim of study. A ghost polarimetry system using a spatial light modulator to measure the optical fields illuminating an object with linear dichroism is developed. Method. Ghost polarimetry is used to measure the integral intensity of radiation passing through an object. The intensity correlation functions are numerically calculated for two orthogonally polarized sets of optical fields for subsequent calculation of the modulus of the anisotropy azimuth for an object with linear dichroism. Main results. A ghost polarimetry device using a spatial light modulator is developed to measure the characteristics of structured optical fields. Images showing the polarization properties of three objects with linear dichroism are obtained. Practical significance. Ghost polarimetry has several advantages over traditional methods of obtaining polarization images when imaging objects with low radiation intensity, when imaging in high-turbulence environments, or when imaging in spectral ranges for which traditional measuring instruments are expensive or unavailable. The inclusion of a spatial light modulator in the ghost polarimetry device means it is no longer necessary to record the fields generated. This modification will enable the characteristics of optical fields for specific objects to be varied for microbiological and medical research.

Photocatalytic reduction of biomass‐derived aldehydes over Pt‐loaded on NiIn bimetallic oxides under light‐emitting diode lighting at mild conditions

Photocatalytic conversion of renewable biomass‐derived aldehydes into high‐valued chemicals is a promising path to meet the growing demand for clean energy and chemical resources. However, the approach still faces challenges, such as limited reaction types and low utilization rates due to the complex functional groups and involved polytropic reaction. In the present work, we developed a catalyst of Pt nanoparticles (Pt NPs) supported on a NiO–In2O3 bimetallic oxide (denoted as Pt/NiInOx) for photocatalytic hydrogenation of furfural (FAL) to furfural alcohol (FOL). Owing to the excellent band structure and efficient internal charge transfer on the p–n heterojunction in the catalyst, the highest 99.9% yield to FOL was obtained over the Pt/NiInOx under a light‐emitting diode (LED) light at low temperatures as 273 K. The combination of ·H dissociated from H2 and oxygen vacancy work synergically to adsorb, activate, and converse C=O to the C–O group. The photocatalytic system presents a highly efficient approach for the rapid hydrogenation of biomass‐based aldehydes under a low LED light radiation intensity at a low temperature. The work is expected to serve as an important reference in constructing bimetallic oxide‐supported active metals, enabling efficient separation of photogenerated electrons and holes, and offering oxygen vacancies in various photocatalytic reactions.

The Influence of the Heat Transfer Mode on the Stability of Foam Extinguishing Agents

The mass loss mechanisms of an aqueous film-forming foam (AF foam), an AR/AFFF water-soluble film-forming foam extinguishing agent (AR foam), and a Class A foam extinguishing agent (A foam) at different levels of thermal radiation, thermal convection, and heat conduction intensity were studied. At a relatively low thermal radiation intensity, the liquid separation rate of the AF, AR, and A foams is related to the properties of the foam itself, such as viscosity and surface/interface tension, which are relatively independent of the external radiation heat flux of the foam. At low radiation intensity (15 kW/m2 and 25 kW/m2), the liquid separation rate of the AF and A foams is relatively stable. When the heat flux intensity is 35 kW/m2, the liquid separation rate of the AF and A foams increases notably, which may be mainly due to the rapid decrease in foam viscosity. And the mass loss behavior is dominated by liquid separation in the AF, AR, and A foams under the influence of thermal radiation and thermal convection. Under the same experimental conditions, the liquid separation rate of AF is the fastest. There is no significant difference in the evaporation rates of the three kinds of foam in the same heat conduction condition. In addition, the AR and A foams usually have a 25% longer liquid separation time (t) under thermal radiation and thermal convection, and the thermal stability is better than AF foam. The temperature reached by the AF foam layer under thermal convection was lower than that of the AR and A foams, and the time for the foam layer to reach the highest temperature under heat conduction was longer than that of the AR and A foams.

A Numerical Study to Improve the Efficiency of Solar Collector used for water heating using Phase Change Material

Solar water heaters are an effective technology for harnessing renewable solar energy to provide hot water for households and businesses. However, their efficiency can be impacted by factors like intermittent sunshine, heat losses, and low radiation intensity. The aim of this study is to increase the efficiency of solar water heaters through the use of phase change materials (PCMs). PCMs have the ability to store latent heat during phase change, releasing it later when needed. This study uses numerical simulations to analyze the effect of integrating different PCMs into a flat plate solar collector design. The findings could then be validated experimentally and applied to improve the real-world performance of solar water heating systems. The PCMs are placed inside the collector to absorb heat during the day and release it after sunset to continue heating the water. The research seeks to determine the optimal PCM properties, structure, and placement within the collector to maximize heat storage and transfer. The efficiency and performance of the solar collector system with different PCM configurations have been compared to those of a conventional collector without PCM. The outcomes uncover that the use of suitable PCMs can significantly improve the efficiency and heat output of the solar collector, especially during periods of low radiation and after sunset. The optimal PCM configuration maintains higher water temperatures for longer, allowing solar water heating to continue into the evening. The results may provide valuable insights for using PCMs to boost the efficiency of solar thermal technologies

Controllable preparation of Ag@Fe3O4 core-shell nanoparticles and evaporation characteristics of nanoparticles-modified carbon membranes

To improve the ability of the medium to capture solar energy, Ag@Fe3O4 core-shell nanoparticles (NPs) were prepared in this paper. The influences of different preparation conditions on the particle structure and photo-thermal properties were investigated, and the growth and spectral absorption properties of Ag@Fe3O4 NPs were analyzed. At the same time, nanoparticles-modified carbon membranes (NPCMs) were prepared by electrostatic adsorption method. The influences of radiation intensity and preparation concentration on photo-thermal properties were investigated, and the local evaporation mechanism of NPCMs was deeply explored. Experiments showed that changing the molar ratio of the precursor can effectively regulate the structure and optical properties of the NPs. The increase of the core radius of the NPs will increase the electric field strength (E) of the core surface and promote the absorption of light. Optimizing the temperature and heating time of the preparation process is very important for the successful realization of Fe3O4 coated Ag, while deepening the coupling between plasmons on the surface of adjacent NPs. Compared with the intensity of 5 sun, the evaporation efficiency at 2 sun is increased by 13.37%. The local evaporation effect caused by NPCMs makes the system still have good evaporation efficiency at low radiation intensity.

Development of a dynamic gas lock inhibited model for EUV-induced carbon deposition.

The optical surface of extreme ultraviolet (EUV) lithography machines is highly vulnerable to contamination by hydrocarbons, resulting in the formation of carbon deposits that significantly degrade the quality and efficiency of lithography. The dynamic gas lock (DGL) has been proven as an effective approach to alleviate carbon deposition. However, the majority of existing studies on carbon deposition neglect the influence of the DGL. This paper is dedicated to investigating the phenomena of hydrocarbon adsorption, desorption, and cleavage with considering the effects of the DGL. A comprehensive mathematical model of the carbon deposition process is established, and the impact of radiation intensity, temperature, and hydrocarbon types on the depositing rate is considered. The results suggest that the primary cause of carbon deposition is the direct cracking of hydrocarbons induced by photons with a wavelength range between 12.5 and 14.5nm. Additionally, it has been observed that the carbon deposition rate decreases exponentially as clean gas flow increases when EUV radiation intensity exceeds 50 mW/mm2. Conversely, at low EUV radiation intensity, clean gas flow has little effect on the carbon deposition rate. An effective approach to mitigate carbon deposition is to elevate the temperature of the optical surface and employ light hydrocarbon materials in the EUV process.

Artificial Skin with Patterned Stripes for Color Camouflage and Thermoregulation.

Chameleons are famous for their quick color changing abilities, and it is commonly assumed that they do this for camouflage. However, recent reports revealed that chameleons also change color for body temperature regulation. Inspired by the structure of the panther chameleon's skin, a stripe-patterned poly(N-isopropylacrylamide) (PNIPAM) and polyacrylamide (PAM) hydrogel film with a laminated structure is fabricated in this work; thus, both camouflage and thermoregulation can be achieved through controlling Vis and NIR light effectively. For the PNIPAM stripe, the upper layer is the native PNIPAM hydrogel and the lower layer is the carbon nanotube-composited PNIPAM hydrogel. Thus, the PNIPAM stripe is capable of reaching 28 °C at a low environmental temperature (12 °C) and a low radiation intensity (20 mW cm-2), while preventing the body temperature from rising by changing to white under a strong radiation intensity (100 mW cm-2). For the PAM stripe, the upper layer combines colloidal photonic crystals and displays a tunable structural color by stretching, and the lower layer is mixed with PNIPAM microgels for thermal regulation. Through the fabrication of multifunctional patterns, the film can achieve both dynamic structural color and thermoregulation by precisely controlling solar radiation absorption, scattering, and reflection. More importantly, in the stripe-patterned system, the shrinkage of the PNIPAM stripes can effectively trigger the elongation of the PAM stripe, which endows the structural color changing process to be self-powered completely. The performances show that the stripe-patterned film may have potential applications in intelligent coatings, especially in areas with large temperature differences during the day such as high plains.

Aggregation-induced emission photosensitizer/bacteria biohybrids enhance Cerenkov radiation-induced photodynamic therapy by activating anti-tumor immunity for synergistic tumor treatment

Cerenkov radiation-induced photodynamic therapy (CR-PDT) gets rid of the limited tissue penetration depth of the external light source and provides a feasible scheme for the PDT excited by the internal light. However, due to the low luminescence intensity of Cerenkov radiation, CR-PDT alone cannot effectively inhibit tumor growth, curbing the potential clinical translation of CR-PDT. Herein, we reported an AIE-PS/bacteria biohybrid (EcN@TTVP) composed of Escherichia coli Nissle 1917 (EcN) loaded with aggregation-induced emission photosensitizer (AIE-PS) termed TTVP, which enhanced CR-PDT by activating anti-tumor immunity for synergistic tumor treatment. The preferential tumor-colonized EcN@TTVP and radiopharmaceutical 18F-fluorodeoxyglucose (18F-FDG) were administered sequentially to enable them to co-enrich in the tumor site, thereby triggering CR-PDT and promoting immunogenic tumor cell death. Most importantly, EcN acting as immunoadjuvants enhanced the maturation of dendritic cells (DCs) and priming of cytotoxic T cells (CTLs). Therefore, under the synergistic treatment of CR-PDT and immunotherapy, AIE-PS/bacteria biohybrids resulted in either efficient tumor remission or a survival prolongation in tumor-bearing mice, which presented significant advantages over single CR-PDT. Remarkably, no obvious toxic effects were observed during the treatment. In this study, we proposed a synergistic therapeutic strategy based on EcN@TTVP for combined CR-PDT and immunotherapy against tumors. Moreover, this strategy may have great potential in clinical translation and provide references for deep-seated tumor treatment. Statement of significancePDT is restricted due to the shallow penetration depth of light into tumor tissues. Using CR as the excitation light source for PDT can overcome the aforementioned issue and greatly expand the application of PDT. However, the low efficacy of single CR-PDT limits further its applications. Therefore, the design and development of feasible strategies to improve the efficacy of CR-PDT are of immediate importance. Introducing probiotics to our study can be used not only as tumor-targeting carriers of photosensitizers but also as immunoadjuvants. Under co-stimulation by immunogenic tumor cell death triggered by CR-PDT and probiotics acting as immunoadjuvants, anti-tumor immune responses were effectively activated, thus remarkably enhancing the efficacy of CR-PDT.

An Autonomous Clutter Inspection Approach for Radiological Survey Using Mobile Robot

In the event of a radiological emergency, scattered clutters around the accident sites should be thoroughly inspected as they are potentially contaminated and require proper safety handling. The goal of this work was to localise the position of the hotspot within the clutters and estimate their respective radiation intensity using a mobile robot. Given the information from a 2D occupancy map, we proposed a strategy to identify the position of clutters and formulate waypoints that simultaneously serve as sampling positions to acquire radiation measurement. Particle filter was adapted to fuse the measured data and provide the results in real-time. We also introduced clutter contamination analysis that takes into account the limitations of the detector to derive the worst-case scenario; thus, preventing misclassifications of hotspots with low radiation intensity as clean areas. The approach was implemented in ROS and a commercial mobile robot with a Geiger Muller detector. Finally, we evaluated the overall performance in simulation and real-world experiments. Note to Practitioners—This work was motivated by the goal of realising automation of clutter inspection using a mobile robot to complement the current achievement in robotics radiation mapping. Currently, we still rely on human workers to conduct a thorough radiation survey, including detailed inspections on all clutters, before clearing any radiological accident or incident site. The theoretical framework in this paper proposed a practical solution to localise and estimate the intensity of the hotspot within the clutter in real-time. We demonstrated the versatility and performance of our proposed approach using a small commercial robot and Geiger Muller tube (typically available in any radiation facilities). This method reduces radiation exposure to human workers and provides a cost-effective solution for preliminary screening in radiological emergency situations.

DETERMINING GAMMA SOURCE IN URANIUM MOLYBDENUM OF FUEL IN G.A SIWABESSY MULTI PURPOSE REACTOR

Nuclear fission reactions produce a lot of radionuclides that release energy, one of which is in the form of gamma radiation. Gamma radiation is produced by various types of radionuclides, and nuclear reactor fuel will produce different values of gamma intensity. Uranium Molybdenum (U7Mo-Al) is the type of nuclear fuel for future research reactors that possesses many advantages. For the application of molybdenum-based fuel, it is necessary to determine the resulting gamma radiation. The purpose is to determine the gamma radiation produced from molybdenum-based fuel with various densities. This study begins with the determination of the mass composition of the reactor component, calculations with ORIGEN2.1, and data output analysis. The U7Mo-Al density was varied, namely 2.96 gU/cm3, 3.85 gU/cm3, 4.44 gU/cm3, 5.43 gU/cm3, 6.91 gU/cm3, and 8.29 gU/cm3. The gamma radiation yield of U7Mo-Al is lower than that of uranium silicide (U3Si2) with the same density of 2.96 gU/cm3. The result will add to the justification for the superiority of U7Mo-Al compared to U3Si2/Al. For U7Mo-Al with densities of 3.85 gU/cm3, 4.44 gU/cm3, 5.43 gU/cm3, 6.91 gU/cm3, and 8.29 gU/cm3, the one that produced the lowest gamma radiation intensity is 3.85 gU/cm3 while the highest is 8.29 gU/cm3. This explains that the intensity of the gamma radiation produced is directly proportional to the fuel density. The low intensity of gamma radiation in molybdenum-based fuel can be used as a suggestion in shielding design to ensure the operational safety of reactors.

Experimental investigation on the impact of fin structure factors on the finned-Trombe wall thermal performance

By increasing surface area, fins can enhance the heat transfer and improve the Trombe wall thermal performance. However, there is still a lack of detailed experimental research on the impact of fin structure factors on the thermal performance of finned-Trombe wall (F-TW). This experiment establishes a platform under laboratory conditions to investigate the impact of fin height and spacing on the F-TW thermal performance. Electric heating is used to simulate the solar radiation. The results indicate that in areas with relatively low solar radiation intensity, the F-TW is more cost-effective for improving F-TW thermal performance. The F-TW thermal parameters including air temperature rise, mass flow rate, thermal efficiency and overall natural convective heat transfer coefficient are enlarged as the fin height increases and fin spacing decreases, while the heat loss coefficient of glass cover is opposite. The fin spacing has a more significant influence on the F-TW thermal performance and natural convective heat transfer in the channel than the fin height does. The maximum thermal efficiency of 63.75% is obtained at heat flux of 860W/m2, relative fin height of 0.75 and relative fin spacing of 0.06. Finally, for the engineering design and performance assessment of F-TW, the experimental correlation is provided to calculate the average natural convective heat transfer Nusselt number in the channel.

The distribution of submerged macrophytes in response to intense solar radiation and salinity reveals hydrogen peroxide as an abiotic stress indicator

The feasible condition for submerged macrophyte growth is hard to understand as many environmental factors contribute to establishing macrophyte distribution with different intensities generating excess reactive oxygen species (ROS). Among various kinds of ROS, hydrogen peroxide (H2O2) is relatively stable and can be measured accurately. Thus, for the quantification of submerged macrophyte species, H2O2 can be used to evaluate their distribution in a lake. Submerged macrophytes, such as Potamogeton anguillanus, were abundant in Lake Shinji. The largest biomass distribution was around 1.35 m deep, under low solar radiation intensity, and nearly no biomass was found less than 0.3 m deep, where solar radiation was high. Tissue H2O2 concentrations varied in response to the diurnal photosynthetically active radiation (PAR) intensity, which was followed by antioxidant activities, though slightly delayed. Laboratory experiments were conducted with different PAR intensities or salinity concentrations. A stable level of H2O2 was maintained up to about 200 μmol m−2 s−1 of PAR for 30 days, followed by a gradual increase as PAR increased. The H2O2 concentration increased with higher salinity. A change in Chlorophyll a (Chl-a) concentration is associated with an altering H2O2 concentration, following a unique negative relationship with H2O2 concentration. If H2O2 exceeded 45 μmol/gFW, the homeostasis collapsed, and H2O2 and Chl-a significantly declined afterward. The above findings indicate that H2O2 has a negative effect on the physiological condition of the plant. The increase in H2O2 concentration was prevented by antioxidant activities, which elevated with increasing H2O2 concentration.

Supplemental Lighting Quality Influences Time to Flower and Finished Quality of Three Long-Day Specialty Cut Flowers

Year-round demand for locally sourced specialty cut flowers continues to increase. However, due to low radiation intensities and temperatures, growers in northern latitudes must utilize greenhouses, but limited production information detailing manipulation of the radiation environment exists. Therefore, our objective is to quantify the influence of supplemental lighting (SL) quality on time to flower and harvest and stem quality of three long-day specialty cut flowers. Godetia ‘Grace Rose Pink’ (Clarkia amoena), snapdragon ‘Potomac Royal’ (Antirrhinum majus), and stock ‘Iron Rose’ (Matthiola incana) plugs are transplanted into bulb crates and placed in one of six greenhouse compartments with SL providing a total photon flux density of 120 µmol·m−2·s−1 from 0700 to 1900 HR. After four weeks, SL is extended to provide a 16 h photoperiod to induce flowering. SL treatments are provided by either high-pressure sodium (HPS) fixtures or various light-emitting diode (LED) fixtures. Treatments are defined by their 100 nm wavebands of blue (B; 400–500 nm), green (G; 500–600 nm), red (R; 600–700 nm), and far-red (FR; 700–800 nm) radiation (photon flux density in μmol·m−2·s−1) as B7G60R44FR9 (HPS120), B20G50R45FR5, B20R85FR15, B30G25R65, B120, or R120. Time to harvest (TTH) is up to 14, 15, and 10 d slower under R120 SL for godetia, snapdragon, and stock, respectively, compared to the quickest treatments (HPS120, B120, and B20R85FR15 SL). However, R120 SL produces cut flowers up to 18% longer than those grown under the quickest treatments. Both broad-spectrum LED fixtures slightly delay TTH compared to the quickest treatments. Stem caliper is not commercially different between treatments for godetia or snapdragon, although stems are up to 14% thinner for stock grown under B120 SL compared to the other treatments. Flower petal color is not commercially different between SL treatments. We recommend utilizing a SL fixture providing a spectrum similar to B20R85FR15 SL or B20G50R45FR5, as they elicit desirable crop responses with minimal developmental, quality, and visibility tradeoffs. While HPS lamps perform similarly to the recommended fixtures, we recommend utilizing LEDs for their higher photon efficacy and potential energy savings.

Experimental and Computational Analysis of Aluminum-Coated Dimple and Plain Tubes in Solar Water Heater System

Solar power is often regarded as one of the most promising forms of alternative energy since it is both sustainable and renewable. It is difficult to utilize and benefit from solar energy in residential and industrial applications because of the intermittent nature of its supply. A solar-based water heating system is efficient for using solar thermal conversion, the simplest and most successful method of turning solar energy into thermal energy. In this research, the performance analysis of Parabolic Trough Solar Collectors (PTSCs) with aluminum-coated copper dimple tubes was computationally and experimentally analyzed. For computational analysis, a Computational Fluid Dynamics (CFD) tool was used. For experimental analysis, aluminum-coated dimple tubes were used to pass the base fluid (water) in it while varying the mass flow rate from 1.0 to 3.0 kg/min at steps of 0.5 kg/min to examine the effect of dimple texturing and aluminum coating on the performance of the solar water heater. The parameters, such as thermal efficiency, friction factor, convective heat transfer coefficient, Nusselt number, and effectiveness of the PTSC, were analyzed, and we found remarkable improvement towards high conversion efficiency. At a flow rate of 2.5 kg/min, the thermal efficiency was improved by about 36%, the friction factor increased by about 0.32%, the convective heat transfer coefficient was improved by 1150 W/m2K, Nusselt number was improved by about 53.8 and the effectiveness was enhanced by 0.4. The simulation results were compared with the experimental results, and the deviation was about ±3.8%, which may be due to an error in the instrument as well as environmental conditions during the analysis. The outcome of results can be used for real-life applications in industrial water heating and domestic water heating especially, the places exposed to low solar radiation intensity throughout the year.

Effects of aspect ratio and inlet wind velocity on thermal characteristics of Trombe wall channel under different ventilation strategies: An indoor experiment

Due to the air flow channel's “C”-shaped structure with asymmetric thermal boundary conditions, the structural and operating parameters have unique intrinsic impacts on overall performance of Trombe wall. In order to match the engineering practice well, under laboratory conditions, an experimental research platform with adjustable channel width and fans was established to reveal the effects of aspect ratio and inlet wind velocity on thermal characteristics of air flow channel under different ventilation strategies. The results show that under natural ventilation strategy, the air flow channel's thermal performance has an extremum when the aspect ratio is about 0.05. Under forced ventilation strategy, with the growth of inlet wind velocity, the comprehensive average convective heat transfer coefficient rises while thermal efficiency shows different trends under various heat fluxes and reaches the maximum when heat flux is greater than 360 W/m2 and inlet wind velocity is 0.6 m/s. A larger aspect ratio leads to a lower comprehensive convective heat transfer coefficient and a smaller thermal efficiency. Compared with the natural ventilation strategy, except for the air temperature rise, the air flow channel's thermal performance is improved to a certain extent under forced ventilation strategy. The improvement of thermal efficiency is particularly significant when the heat flux is small, indicating that forced ventilation strategy has high application potential in areas with low solar radiation intensity. Finally, the Nusselt number correlations reflecting comprehensive average convective heat transfer performance of Trombe wall channel under two ventilation strategies were obtained for engineering design and performance evaluation of Trombe wall.