Effects of the Light Irradiance on the Growth and Lipids Content of Amphidinium Carterae (Dinophyceae) for Biofuels Production

The irradiance level used to the microalgae cultures can modify the growth and proximate composition, however, this response is specie specific. The dinoflagellate group had the potential to be used as a source to biofuel production. In this study was evaluated the effect of five irradiance levels (50, 100, 150, 200, and 250 µmol photon m-2 s­-1) on the growth rate, proximal composition, pigment content, and photosynthesis of Amphidinium carterae. The highest cell concentration was for the cultures at 150 µmol photon m-2 s-1 (130 × 103 cells mL-1), and the lowest values for 50 µmol photon m-2 s-1 (49 × 103 cells mL-1). The cultures maintained under the low irradiance (50 µmol photon m-2 s-1) had the highest values of total dry weight (TDW) (13418 pg cell-1), organic dry weight (ODW) (3836 pg cell-1), and inorganic dry weight (IDW) (9582 pg cell-1). The protein content as the general trend increases significantly concerning the irradiance level, with the higher values (87.47 pg cell-1) at high irradiance (250 µmol photon m-2 s-1). Carbohydrate content was different by the effect of irradiance, with the higher values (32.85 pg cell-1) at the low irradiance used (50 µmol photon m-2 s-1). Lipid content was modified by the effect of irradiance, with the highest values (534.74 pg cell-1) at the low irradiance used (50 µmol photon m-2 s-1). As a general trend, the high irradiances increased the photosynthesis curves. These findings demonstrate that the strain of A. carterae used in this work can grow in high irradiances (100 to 250 µmol photon m-2 s-1) and increase significantly the lipid content on low irradiance used (50 µmol photon m-2 s-1).

A Novel Photovoltaic Module Quick Regulate MPPT Algorithm for Uniform Irradiation and Partial Shading Conditions

This study proposed a new photovoltaic module quick regulate (PVM-QR) maximum power point tracking (MPPT) algorithm, which can eliminate the disturbance problem of the hill-climbing (HC) algorithm, especially under low irradiance level and partial shading conditions (PSC). This proposed algorithm has the advantage that it only uses the detection photovoltaic module (PVM) impedance and the open-circuit voltage to simply and quickly calculate the PVM temperature, the irradiance level, and then the key factor parameter u. To achieve the MPPT quickly and accurately, this proposed algorithm is developed for the prediction of the best MPPT duty cycle based on the irradiance level, parameter u, and load. This study verified the proposed MPPT by the measurement results, where the HC algorithm MPPT has 95% efficiency at 0.55 kW/m2 but diverges at 0.2 kW/m2 under uniform irradiation conditions (UIC), and the proposed MPPT algorithm has an improved efficiency (99%) under the same conditions. Moreover, the proposed MPPT algorithm has 99% efficiency under PSC, while the HC algorithm MPPT’s efficiency is 66%. This study implemented a simple-design circuit with the proposed MPPT algorithm for UIC and PSC, where the actual experiment results can also verify that the proposed algorithm performs better than the HC algorithm.

Flow-Through Portable Antivirus UV-C Optical Enclosures to be Used with Protective Masks

UV-C light is an important disinfection tool against airborne viruses, while also being harmful if the light reaches the human skin. Body-attached reflective flow-through optical enclosures can be used for isolating the UV-C light from the user as well as elevating the irradiance level. In this study, we explain why air-sterilizing light enclosures are more effective than the expectations by introducing a dose multiplication factor of 4. As a result of omnidirectional illumination, air sterilization becomes more effective than surface disinfection if similar irradiance levels are measured from the enclosure wall. The methodology is explained by the design of a portable enclosure device primarily targeting the COVID-19 virus, and disinfection effectiveness better than 99.5% is demonstrated by biological tests.

Irradiance footprint of phototherapy devices: a comparative study

Background Phototherapy (PT) is the standard treatment of neonatal unconjugated hyperbilirubinemia. The irradiance footprint, i.e., the illuminated area by the PT device with sufficient spectral irradiance, is essential for PT to be effective. Irradiance footprint measurements are not performed in current clinical practice. We describe a user-friendly method to systematically evaluate the high spectral irradiance (HSI) footprint (illuminated area with spectral irradiance of ≥30 μW cm−2 nm−1) of PT devices in clinical practice. Materials and methods Six commercially available LED-based overhead PT devices were evaluated in overhead configuration with an incubator. Spectral irradiance (µW cm−2 nm−1) and HSI footprint were measured with a radiospectrometer (BiliBlanket Meter II). Results The average measured spectral irradiance ranged between 27 and 52 μW cm−2 nm−1 and HSI footprint ranged between 67 and 1465 cm2, respectively. Three, two, and one PT devices out of six covered the average BSA of an infant born at 22, 26–32, and 40 weeks of gestation, respectively. Conclusion Spectral irradiance of LED-based overhead PT devices is often lower than manufacturer’s specifications, and HSI footprints not always cover the average BSA of a newborn infant. The proposed measurement method will contribute to awareness of the importance of irradiance level as well as footprint measurements in the management of neonatal jaundice. Impact While a sufficient spectral irradiance footprint is essential for PT to be effective, some PT devices have spectral irradiance footprints that are too small to cover the entire body surface area (BSA) of a newborn infant. This study introduces a user-friendly, accessible method to systematically evaluate the spectral irradiance level and footprint of PT devices. This study supports awareness on the role of the spectral irradiance footprint in the efficacy of PT devices. Irradiance footprint can be easily measured during phototherapy with the proposed method.

Experimental determination of the evolution of the incident heat flux received by a combustible during a cone calorimeter test: Influence of the flame irradiance

The decomposition kinetic of polymeric materials in a cone calorimeter strongly depends on the irradiance level imposed at the sample’s surface. Indeed, even if the irradiance level is supposed to be kept constant during cone calorimeter test, the amount of heat flux which is emitted by the flame can greatly increase the total heat flux received by the material. Analytical treatment on recently obtained results of an acrylonitrile-butadiene-styrene’s mass loss rate with controlled atmosphere cone calorimeter has shown that the differences observed between well-ventilated and inert environments can be attributed to the impact of the flame. This observation has brought the necessity to determine the impact of the flaming process on the material thermal decomposition. To do so, series of experiments have been devised, based on the insertion of a heat fluxmeter within the matrix of an acrylonitrile butadiene styrene material, during cone calorimeter tests in order to measure the flame heat flux as a function of the decomposition and the combustion processes.

The impact of high temperature and irradiance source on the efficiency of polycrystalline photovoltaic panel in a controlled environment

Solar cells are highly sensitive to temperature, which affects its operating parameters. The study has its aim in accessing the impact of temperature (in excess above the maximum operating cell temperature) and irradiance source on the efficiency of polycrystalline photovoltaic (PV) solar panels in an environment where the temperature and irradiance level can be fully controlled. For the study to achieve its aim, a solar box and tungsten light bulbs were used to create an environment where the irradiance level and the temperature can be controlled. The solar panel was placed inside the solar box facing the light source while the irradiance level and temperature were measured and held constant. Results show a steady decrease in voltage with increasing temperature while the performance ratio and efficiency of the photovoltaic module followed a similar trend as that of voltage once the temperature exceeds the maximum operating cell temperature. Results also show the output voltage of the photovoltaic to be higher under the tungsten light than the sun, but the efficiency achieved by the photovoltaic under the sun far exceeds that obtained under the tungsten light.

A Novel Variable Step Size Incremental Conductance Method with an Adaptive Scaling Factor

In this paper, a novel variable step size (VSS) incremental conductance (INC) method with an adaptive scaling factor is proposed. The proposed technique utilizes the model-based state estimation method to calculate the irradiance level and then determine an appropriate scaling factor accordingly to enhance the capability of maximum power point tracking (MPPT). The fast and accurate tracking can be achieved by the presented method without the need for extra irradiance and temperature sensors. Only the voltage-and-current sets of any two operating points on the characteristic curve are needed to estimate the irradiance level. By choosing a proper scaling factor, the performance of the conventional VSS INC method can be improved. To validate the studied algorithm, a 600 W prototyping circuit is constructed and the performances are demonstrated experimentally. Compared to conventional VSS INC methods under the tested conditions, the tracking time is shortened by 31.8%. The tracking accuracy is also improved by 2.1% and 3.5%, respectively. Besides, tracking energy loss is reduced by 43.9% and 29.9%, respectively.