Maximum Irradiance Research Articles

Investigation of OFDM-Based HS-PON Using Front-End LiFiSystem for 5G Networks

Fifth-generation (5G) technology has enabled faster communication speeds, lower latency, a broader range of coverage, and greater capacity. This research aims to introduce a bidirectional high-speed passive optical network (HS-PON) for 5G applications and services including mobile computing, cloud computing, and fiber wireless convergence. Using 16-ary quadrature amplitude modulation orthogonal frequency division multiplexing techniques, the system transmits uplinks and downlinks with a pair of four wavelengths each. Light fidelity (LiFi) services are provided with blue light-emitting-diode-based technology. With a threshold bit error rate (BER) of 10−3, the results demonstrate reliable transportation over a 100 km fiber at −17 dBm received power and in a maximum LiFi range of 20 m. Furthermore, the system offers symmetric 4 × 50 Gbps transmission rates under the impact of fiber–LiFi channel impairments with maximum irradiance and incidence half-angles of 500. Additionally, at threshold BER, the system provides a detection surface range from 1.5 to 4 cm2. Compared to existing networks, the system also provides a high gain and low noise figure. A number of features make this system an attractive option. These include its high speed, high reach, high split ratio, low cost, easy upgradeability, pay-as-you-grow properties, high reliability, and ability to accommodate a large number of users.

Development of crude oil desalination unit by using solar flat plate collectors

To date, two-thirds of the world's crude oil reservoirs need desalination treatment to remove the salt content of crude oil. Ensuring the quality of produced crude oil shows the critical need for desalting units. But, these plants are one of the high-energy consuming processes, especially in the indirect-fired heaters. In this concern, exergy analysis investigated the thermodynamic efficiency of the plant's equipment. Aspen Hysys, and Matlab software are used for simulating and calculating the integrated system based on solar flat plate collectors. Based on exergy analysis, the most inefficient equipment are the skimmer tank, and dual indirect fired heaters by 680, 262 and 216 kW, respectively. Regarding the high rate of exergy destruction in the indirect fired heaters, implementing solar flat plate collectors as alternative equipment that is economically affordable was considered. The desalination unit has significant potential for using solar flat plate collectors, as determined by key solar characteristics such as temperature, clearness index, and daylight length. Mathematical modeling shows that maximum solar irradiation was attained at altitude angle (31°). The economical optimal area was assessed based on the life cycle saving cost parameter. After obtaining the optimal area, it was found that using 52000 m2 of solar flat plate can supply a proper substitute for inefficient heaters. A comprehensive economic analysis of this proposed plan is based on effective indicators, such as purchase side costs, maintenance costs, and fuel inflation rate. The economic results show that the investment cost will be reimbursed 14 years after start-up. This optimum area can reduce CO2 emission of heaters up to 83 %.

Simulation study of a novel small animal FLASH irradiator (SAFI) with integrated inverse-geometry CT based on circularly distributed kV X-ray sources

Ultra-high dose rate (UHDR) radiotherapy (RT) or FLASH-RT can potentially reduce normal tissue toxicity. A small animal irradiator that can deliver FLASH-RT treatments similar to clinical RT treatments is needed for pre-clinical studies of FLASH-RT. We designed and simulated a novel small animal FLASH irradiator (SAFI) based on distributed x-ray source technology. The SAFI system comprises a distributed x-ray source with 51 focal spots equally distributed on a 20 cm diameter ring, which are used for both FLASH-RT and onboard micro-CT imaging. Monte Carlo simulation was performed to estimate the dosimetric characteristics of the SAFI treatment beams. The maximum dose rate, which is limited by the power density of the tungsten target, was estimated based on finite-element analysis (FEA). The maximum DC electron beam current density is 2.6 mA/mm2, limited by the tungsten target's linear focal spot power density. At 160 kVp, 51 focal spots, each with a dimension of 2times 20 mm2 and 10° anode angle, can produce up to 120 Gy/s maximum DC irradiation at the center of a cylindrical water phantom. We further demonstrate forward and inverse FLASH-RT planning, as well as inverse-geometry micro-CT with circular source array imaging via numerical simulations.

An Automatic PI Tuning Method for Photovoltaic Irrigation Systems Based on Voltage Perturbation Using Feedforward Input

This paper proposes a new automatic tuning method for the proportional-integral (PI) controllers of photovoltaic irrigation systems (PVIS) without the need for any other power source or batteries. It enables the optimisation of the values of the PI parameters (Kp and Ki) automatically, eliminating the requirement for skilled personnel during the installation phase of PVIS. This method is based on the system’s voltage response when a disturbance signal is introduced through the feedforward input of the PI controller. To automatically assess the response properties, two indicators are proposed: the total harmonic distortion (THD), used to evaluate the sine response, and the total square distortion (TSD), used to evaluate the square response. The results indicate that the tuning changes for different irradiance and temperature conditions due to the non-linearity of the system, obtaining the most conservative values at maximum irradiance and temperature. The robustness of the results of the new automatic tuning method to abrupt photovoltaic (PV) power fluctuations due to clouds passing over the PV generator has been experimentally tested and the results show that the obtained tuning values make the PVIS stable, even when PV power drops of 66% occur abruptly.

Low-carbon methanol production using solar thermal energy: A techno-economic assessment

This work presents a techno-economic and greenhouse gas emissions assessment of a proposed low-carbon methanol production process. The process takes a novel low-carbon methanol production method and reduces its emissions further by integrating a solar thermal energy (STE) system to provide for its electricity requirements. The authors investigate three different scenarios for the STE system, analysing the effects of solar irradiance design point, and the impact of thermal energy storage on system performance. Case-1 (15.57 MW) was designed for daytime operation and sized for the maximum annual solar irradiance, with Case-2 (24.91 MW) incorporating thermal energy storage to enable 24-hour operation. Case-3 (48.66 MW) also utilised thermal energy storage to enable 24-hour operation, but was sized for the minimum annual solar irradiance. The methanol process and the STE system were modelled in Aspen Plus and Aspen HYSYS, with the simulation data being used with mass and energy balances to conduct a techno-economic and greenhouse gas emissions assessment. The standalone methanol plant was estimated to emit 0.37 t CO2/t CH3OH, with the integration of the STE system reducing this to 0.29 (Case-1), 0.23 (Case-2), and 0.10 (Case-3), resulting in one of the lowest emitting traditional methanol production methods available. The cost of abatement of these remaining emissions through carbon capture and storage was also considered. The economic analysis found that the integrated processes in Case-1 and 2 were financially viable, resulting in a net present value of $247 million and $72 million respectively. The net present value was reduced to $185 and $21 million when considering the cost of carbon capture and storage. Conversely, the net present value for Case-3 was negative, requiring an increase in the price of methanol to ∼$600/t, and a reduction in the cost of capital to ∼8%, to become financially viable.

A method for design optimization of roof-integrated two-stage solar concentrators (TSSCs)

The optimal performance of two-stage solar concentrators (TSSCs) as building-integrated energy solutions is achievable through an integrative design of TSSCs and the building geometry. Such a design process reflects a multi-criteria decision-making problem involving different stakeholders having domain-specific concerns. To support this, in this study, a method to perform a two-step, design optimization of building and TSSCs engineered concerning building geometry is presented by developing a parametric model and applying, a multi-objective optimization algorithm (NSGA-II). The method allows for the creation of different design solutions in several iterations using a population set of individuals (decision variables) related to building design (i.e., roof type and slope, building orientation, length, width, and building type), and TSSC design (type, geometric ratio, mirrors' separation distance, modules number, and receiver area). Thus in several iterations, the method enables finding optimal solutions i.e., building with maximum direct normal irradiance (DNI) and TSSCs with maximum average load match index (av.LMI), and minimum average covered roof area (av.CRA). The application of the method is shown in a case study of four different, hypothetical residential buildings under the climate settings of Berlin. These buildings are illustrative (descriptive), which depict theoretical volumes as abstract representations of future constructions. Thus, a set of simulation runs are performed according to different model settings, to enable early-stage design exploration of future/new constructions which differ in size (varying floor levels) and energy demand. Results indicate that most solutions reflect buildings of high DNI (more than 125 kW/m2/month) and TSSC of av.LMI from 0.4 to 4.2, and av.CRA from 8% to 47%. Nevertheless, the performance of TSSCs depends on the building type. The method enables a performance-driven design approach, searches for the most feasible solutions, and helps to meaningfully support the decision-making process.

Fabrication, swift heavy ion irradiation, and damage analysis of lanthanide targets

Abstract One limiting factor in progress in the discovery and study of new superheavy elements (SHE) is the maximum achievable thickness and irradiation stability of current generation actinide targets. The desired thickness of targets, using full excitation function widths, cannot be achieved with current target technology, especially the widely used molecular plating (MP). The aim of this study was to transfer progress in the electrochemistry of lanthanides and actinides to the production of targets. Here, we report on the production of lanthanide targets using anhydrous electrochemical routes. In a first irradiation series, thulium thin films with areal densities up to 1800 μg/cm2 were produced using anhydrous triflate compounds and subjected to irradiation tests, using 6.0 MeV/u 48Ca ions at a fluence of 3.9 × 1014 ions/cm2 and 8.6 MeV/u 197Au ions at fluences in the range of 3.0 × 1011 to 1.0 × 1013 ions/cm2. The thin films were characterised before and after the irradiations using scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX).

PREOPERATIVE BRAIN IRRADIATION IN GLIOBLASTOMA (POBIG TRIAL): FEASIBILITY AND EVALUATION OF TREATMENT RESPONSE IN ENHANCING AND NON-ENHANCING REGIONS

Abstract AIMS Patients with glioblastoma have dismal outcomes and there is an urgent need for new treatment modalities. The POBIG trial is the first to evaluate the safety and feasibility of single-fraction preoperative radiotherapy for newly diagnosed glioblastoma. We report the results from our first dose arm. METHOD POBIG is a phase I radiotherapy dose and volume escalation trial. The first dose arm received 8Gy preoperative radiotherapy to a maximum irradiation volume of 30cm3. The irradiation field included enhancing and non- enhancing FLAIR hyperintense regions judged as highest risk for remaining as postoperative residuum. Part of the tumour remained unirradiated (<2Gy) with a margin for diagnostic sampling. Surgical resection took place within 1 week. Patients underwent diffusion/perfusion MRI scans before/after preoperative radiotherapy. RESULTS Two female and one male patient aged 61, 67 and 45 years, respectively, were enrolled. Preoperative radio- therapy was delivered at a dose of 8Gy to an irradiation volume of 7-30cm3. Near-total surgical resection was performed 2-3 days after preoperative radiotherapy treatment. Pathological examination of irradiated areas showed necrosis including fibrinoid necrosis of vessel walls. There was an increase in Ktrans permeability in both irradiated enhancing tumour (0.097,0.150) and unirradiated enhancing tumour (0.077,0.147) 24-hours after treatment. In contrast, no obvious changes were noted in irradiated (0.002,0.002) and unirradiated (0.002,0.004) non-enhancing FLAIR hyperintense regions or reference unirradiated contralateral white matter (0.000,0.000). CONCLUSIONS Preoperative radiotherapy is feasible in newly diagnosed glioblastoma. Very early radiotherapy changes manifest in enhancing tumour regardless of radiotherapy dose, evident as increased permeability and radiation- induced tumour necrosis.

Sea Surface Energy Fluxes' Response to the Quasi‐Biweekly Oscillation: A Case Study in the South China Sea

AbstractThe South China Sea (SCS) owns the world's strongest quasi‐biweekly oscillation (QBWO) in boreal summer, but the mechanism is still unclear. This case study summarizes two modes of QBWO over the summer SCS in 2019 by using empirical orthogonal function on the 10–20‐day bandpass‐filtered outgoing longwave radiation fields. The maximum positive irradiance anomalies for the two modes are 90 W m−2. The upward solar and downward longwave radiation anomalies own about 4%–8% of the irradiance magnitude, and the surface upward longwave radiation shows a weak response. Sea surface turbulent heat fluxes' responses to QBWO display different spatial patterns compared to radiation fluxes. Their changes are mainly ascribed to the surface wind in Mode1 and the air‐sea thermal contrast in Mode2. We also discuss the cause and impact of sea surface turbulent heat fluxes on QBWO.

Scavenging of laser-generated aerosols with electrostatic-charged spray droplets

At the Fukushima Daiichi nuclear power station, high radiation hot spots were found at the concrete shield plugs above the Primary Containment Vessel (PCV), indicating that radioactive material may have flowed into narrow gaps at the upper part of the reactor building. High-power fiber lasers can be the preferred choice for cutting fuel debris and cleaning high radiation hot spots due to their advantages over conventional mechanical removal methods. However, laser decontamination generates submicron radioactive particles that pose a risk of internal dose to workers if dispersed. Effective confinement and scavenging are critical to reducing the risk of radiation exposure during decommissioning processes at the Fukushima Daiichi nuclear power station. Various other industries such as coal, mining, and chemical produce flue gases that contain particles smaller than a micron in size, which are harmful to both the environment and human health. To understand the feasibility of implementing an electrostatically charged spray to capture the aerosol particles in decommissioning applications and other industries, laser cleaning experiments were conducted inside UTARTS (University of Tokyo Aerosol Removal Test with Sprays) facility with a class-4 laser having maximum irradiation power of 1.5 kW. Various test samples made of carbon steel (CS), stainless steel (SS), and concrete were coated with CeO2 and cleaned using the laser. The aerosol particles generated during laser decontamination were confined inside the UTARTS and captured using a spray and electrostatic droplet charging system. The study proposes the use of a charged spray, which proves highly efficient for scavenging aerosols generated through laser irradiation. This technique can be used to efficiently decontaminate radiation hotspots adhering to shield plugs, PCV walls, and structures to ensure the safety of operators in high-dose environments and extend the operating time of electronic devices.

Optimum yearly and seasonal tilt angle of solar system in the center of Babylon/Iraq using PVsyst software

The photovoltaic system tilt angle is one of the more significant factors for obtaining the maximum solar energy that will fall on the PV panel. Consequently, then obtain maximum power output, the solar array needs to be angled properly. The analysis for a stand-alone system is simulated and modelled using PVsyst software version-7.2 for system power 3,120 Wp to obtain the optimum value of the tilt angles of maximum solar irradiation in the center of Babylon Governorate, Iraq. The ideal tilt angle for the south has been found for both yearly and the seasons. Different tilt angles were taken which were (29°, 30°, and 31°) annually, azimuth angle for all is (0°). The incident global irradiation in the collector plane, Incident beam irradiation in the collector plane is maximum at tilt angle (29°) that produces maximum available energy 5,132 kWh/kWp/year. same processing for annual different tilt angle was taken for seasonally; the results show that the angle (49°) for summer and (13°) for winter are the optimum tilt angle which obtains the maximum incident global irradiation in the collector plane, maximum incident beam irradiation in the collector plane at this angle then product maximum available energy 5,343 kWh/kWp/year.

On UV Photon Distribution of Discharge in GIS Busbar Based on Ray Tracing

In order to clarify the distribution law of the ultraviolet photon field in gas insulated switchgear busbar, meanwhile to correct the detection range of the ultraviolet sensor, the optical model of the gas insulated switchgear busbar based on the uniform theory of diffraction is proposed based on ray tracing. the distributions of the radiation ultraviolet fields are calculated when partial discharge occurs at the key positions such as basin insulator and conductor. Based on the average irradiance, maximum irradiance, and attenuation characteristics, the distribution law in the busbar is further analyzed, which provides a new method to confirm the location of ultraviolet sensors.

Diffuse and Direct UV Index Experimental Values

In this work, we study the different components of the UV Index, direct, diffuse, and global, for seven years of UV erythemal measurements in a Mediterranean locality at Burjassot AtmoSpheric Station (BASS). The measurements have been taken with three YES-UVB-1 radiometers: one provided with a shadow disk on a Sun tracker; a radiometer to measure the global horizontal radiation; and a Sun-tracking radiometer to measure the direct radiation with an especially designed radiance collimator. It is known that diffuse UV irradiance represents at least 50% of total UV irradiance on a horizontal plane, which means being able to obtain a high UV Index even under shade. Our study aims to establish the relationship between the UV Index at noon and the maximum daily UV erythemal irradiance in the mid-latitude area, as well as the potential erythemal effects of exposure to solar UV radiation on different skin phototypes (skin phototypes I–IV) for both direct and diffuse components.

Exploring the performance of an innovative integrated solar tower power plant with hydrogen generation and storage

This study examines the incorporation of solar tower technology with a Solid Oxide Fuel cell, and a steam turbine to produce power from solar energy. The various subsystems are combined to accomplish high overall energy efficiency, provide steady operation, as well as decrease rate of exergy destruction. In order to ensure a continuous operation, power is produced during the discharge cycle by the Solid Oxide Fuel Cell (SOFC), utilizing the hydrogen produced by the Solid Oxide Electrolysis Cell (SOEC). The energetic and exergetic analyses, as well as the exergoeconomic technique, are applied to evaluate the system's performance indexes. Simulation is conducted for Yazd, Iran, utilizing the maximum solar irradiation. The exergy and economic results of the suggested system demonstrate that the solar tower has the most considerable exergy destruction rate as well as capital investment cost, which is 296.4 MW and 2515$/h, respectively. As a result, this examined work is computed to have 12.73% energy efficiency and 13.39% exergy efficiency.

Which power cycle is the best fit for parabolic trough solar collectors? A comparative and comprehensive case study for six sub-configurations of the three main cycles

In this study, the integration of a Parabolic Trough Collector with different power cycles was investigated on an annual basis in terms of Energy, Exergy, Economics and Environmental under different meteorological conditions. A parabolic trough collector with 500 collectors with a gross and net aperture area of 432,000 and 817.43 m2, was installed in a place that has a high solar energy potential. With a Parabolic trough collector, hourly Direct Normal Irradiation, wind speed, wind direction, ambient temperature and incident angle values were obtained for the 15th of each month for a year. The performance of the 3 power cycles with 6 different configurations using the Parabolic trough collector as the heat source was comprehensively analyzed and compared. During the dynamic data use and various commonly used power systems comparing study, it was aimed to answer the most commonly asked questions by the researchers in this area. To do this, the effect of direct normal irradiation and incident angle on the performance of systems to reach the maximum net power was studied. After calculations, the maximum net power was not found on July 15 (12:00) when the maximum direct normal irradiation (840.868 W/m2) was seen. The maximum net power (67867 kW) was found on September 15 (12:00) when the incident angle was minimum (1.71°) along with the high direct normal irradiation. Steam Rankine Cycle, Organic Rankine Cycle and Kalina Cycle performance comparisons were made both annually depending on time and with different configurations and fluids. In addition to tangibly showing the superiority of incident angle on direct normal irradiation, the present study aimed to present the best-performing system configuration for the researcher, user, scientists, and manufacturers. Interestingly, while the Organic Rankine Cycle with heat exchanger with R123 showed better performance in terms of power production and carbon dioxide emission reduction, the Kalina Cycle was found much more feasible in terms of economics.

Experimental Demonstration of a Visible Light Communications System Based on Binary Frequency-Shift Keying Modulation: A New Step toward Improved Noise Resilience.

Visible light communications (VLC) are an emerging technology that is increasingly demonstrating its ability to provide wireless communications in areas where radio frequency (RF) technology might have some limitations. Therefore, VLC systems offer possible answers to various applications in outdoor conditions, such as in the road traffic safety domain, or even inside large buildings, such as in indoor positioning applications for blind people. Nevertheless, several challenges must still be addressed in order to obtain a fully reliable solution. One of the most important challenges is focused on further improving the immunity to optical noise. Different from most works, where on-off keying (OOK) modulation and Manchester coding have been the preferred choices, this article proposes a prototype based on a binary frequency-shift keying (BFSK) modulation and non-return-to-zero (NRZ) coding, for which the resilience to noise is compared to that of a standard OOK VLC system. The experimental results showed an optical noise resilience improvement of 25% in direct exposure to incandescent light sources. The VLC system using BFSK modulation was able to maintain a maximum noise irradiance of 3500 µW/cm2 as compared with 2800 µW/cm2 for the OOK modulation, and an improvement of almost 20% in indirect exposure to the incandescent light sources. The VLC system with BFSK modulation was able to maintain the active link in an equivalent maximum noise irradiance of 65,000 µW/cm2, as opposed to the equivalent 54,000 µW/cm2 for the OOK modulation. Based on these results, one can see that based on a proper system design, VLC systems are able to provide impressive resilience to optical noise.

Study on UV optical field distribution of partial discharge in GIS disconnector based on ray tracing method

Abstract In order to clarify the distribution law of the radiation optical field of the gas insulated switchgear disconnector defect and determine the detection range of partial discharge optical sensor, the optical model of the gas insulated switchgear disconnector based on the uniform geometrical theory of diffraction theory is established based on ray tracing method, and the distribution of the radiation light field is calculated when partial discharge occurs at the key positions such as the basin insulator, shield, and support insulator barrel. Based on the maximum irradiance, average irradiance and attenuation characteristics on the shell interface, the distribution law is further analysed, and based on this, the optimal location of the ultraviolet detector is proposed.

Ensemble Machine-Learning Models for Accurate Prediction of Solar Irradiation in Bangladesh

Improved irradiance forecasting ensures precise solar power generation forecasts, resulting in smoother operation of the distribution grid. Empirical models are used to estimate irradiation using a wide range of data and specific national or regional parameters. In contrast, algorithms based on Artificial Intelligence (AI) are becoming increasingly popular and effective for estimating solar irradiance. Although there has been significant development in this area elsewhere, employing an AI model to investigate irradiance in Bangladesh is limited. This research forecasts solar radiation in Bangladesh using ensemble machine-learning models. The meteorological data collected from 32 stations contain maximum temperature, minimum temperature, total rain, humidity, sunshine, wind speed, cloud coverage, and irradiance. Ensemble machine-learning algorithms including Adaboost regression (ABR), gradient-boosting regression (GBR), random forest regression (RFR), and bagging regression (BR) are developed to predict solar irradiance. With the default parameters, the GBR provides the best performance as it has the lowest standard deviation of errors. Then, the important hyperparameters of the GRB are tuned with the grid-search algorithms to further improve the prediction accuracy. On the testing dataset, the optimized GBR has the highest coefficient of determination (R2) performance, with a value of 0.9995. The same approach also has the lowest root mean squared error (0.0007), mean absolute percentage error (0.0052), and mean squared logarithmic error (0.0001), implying superior performance. The absolute error of the prediction lies within a narrow range, indicating good performance. Overall, ensemble machine-learning models are an effective method for forecasting irradiance in Bangladesh. They can attain high accuracy and robustness and give significant information for the assessment of solar energy resources.

Pilot Scheme Conceptual Analysis of Rooftop East–West-Oriented Solar Energy System with Optimizer

In recent years, photovoltaic energy has become a popular alternative to traditional fossil fuels due to its renewable and sustainable nature, and the incentives provided by countries to encourage research and development in this field have accelerated the implementation of photovoltaic roofs. One important factor in maximizing the efficiency of solar panels is their orientation to harness maximum irradiation with minimum roof area. In this article, an optimizer-supported east–west-oriented solar power plant installation is experimentally presented to utilize more solar energy with less area compared to wide-area south orientation. Furthermore, an analysis of different angle placements is simulated by PVSOL and PVGIS to test the robustness of the presented approach, and the pros/cons of the features of the east–west and south orientation are discussed comparatively. The obtained results are promising for the ideal placement of solar systems along with the use of optimizers to further enhance their performance, and for the minimization of the economic return of such an investment.

Design of Integrating Sphere Uniform Light System for Solar Simulator

In the process of designing and adjusting the solar simulator, the side lobe effect and aberration of the optical integrator affect the irradiation uniformity, an integrating sphere is proposed to replace the optical integrator for uniform light and the compound parabolic reflector for beam shaping. First, based on the equal illuminance theorem and the radiation transfer theory, the calculation formula of the energy transmission efficiency of the porous integrating sphere is derived; Then, the light hole illuminance interference factor is introduced, and the effects of the aperture size of the integrating sphere, the radius of the integrating sphere, and the size and position of the baffle on the energy transmission efficiency and irradiation uniformity are analyzed. Finally, an integrating sphere uniform light system with high energy transmission efficiency and uniformity is designed and simulated with LightTools software. The simulation results show that: the average difference of irradiation uniformity and the range difference of irradiation uniformity are closest to 1 in the area where the ratio of the opening size and radius of the integrating sphere is 36%–40%, and the light is evenly distributed; When the baffle position is 0.8 times of integrating sphere radius away from the light entrance hole, irradiation non-uniformity at the outlet hole is 1.99%, which is the best position of the baffle; In the effective irradiation surface of Φ1032 mm, the irradiation non-uniformity is 1.98%, and the maximum irradiance is 0.62 solar constants, the spot simulation with high irradiation uniformity on large irradiation surface is realized.