Conventional Lamp Research Articles

Energy Efficiency Project for the Campuses of Unicamp

Unicamp is making progress in making its energy consumption more efficient through partnerships with companies in the electricity sector and projects carried out within the scope of the Coordination of Sustainability. Despite already being able to report a reduction of around 10% in energy consumption during the last four years, it is important for Unicamp to be able to accelerate the transition to a more sustainable operation. The Energy Efficiency Project aims to reduce the university's electricity consumption by 30% by 2030. For this purpose, it is divided into three sub projects aimed at saving energy, modernizing, and improving buildings and the university's sustainability indicators. The Unicamp 100% Led subproject foresees the replacement of conventional lamps by 18W LED tube lamps. The Sustainability in the Air subproject aims to replace old air conditioning equipment with efficient equipment. And the + Photovoltaic subproject aims to increase the generation of photovoltaic energy on the roofs of university buildings. The main goal of this is to report the implementation process of this project, its challenges, results achieved and indicators. The result of this explanation can be used as an example so that other universities can advance in the sustainable management of electric energy.

Effects of Far-Infrared Rays Emitted from Loess Bio-Balls on Lymphatic Circulation and Reduction of Inflammatory Fluids.

Background: FIR therapy is used in various medical settings to treat diseases associated with inflammation and edema. Unlike conventional FIR lamp therapy, this study investigated how body fluids change depending on the intensity and duration of FIR irradiation to the whole body. Method: Subjects in group A (n = 27) were exposed to FIR emitted from a loess bio-ball mat set at 40 °C for 30 min, and subjects in group B (n = 27) were exposed to FIR emitted from a loess bio-ball mat set at 30 °C for 7 h during sleep. Changes in bioimpedance parameters and fluid-related values were measured using a body fluid analyzer before and after exposure to FIR. Results: Changes in bioimpedance parameters associated with inflammatory fluids were quantitatively confirmed. In group A, there was a minimal change in fluid-related measurements. However, significant changes in bioimpedance parameters associated with inflammatory fluids were observed in group B exposure to FIR for 7 h during sleep. Conclusions: FIR emitted from loess bio-balls activates biological tissues and lymphatic circulation, gradually reducing the levels of inflammatory fluids over time.

UVB emitting phosphors based on singly and co-doped Ce3+, Gd3+ in Li4ZrF8 phosphors

Preparation of Li4ZrF8:Ce3+ and Li4ZrF8:Ce3+,Gd3+ phosphors is described. Data on luminescence characteristics are presented. Hydrothermal route was employed for the synthesis. Li4ZrF8 crystallizes in orthorhombic system with Pnma space group. Li atoms are distributed over two sites, both having same coordination of six. Zr is also similarly distributed over two 8 coordinated sites. Li4ZrF8:Ce3+ emits a broad band UVB light, while the emission of Li4ZrF8:Ce3+,Gd3+ is in form of a narrow line around 311 nm attributed to 6P7/2 → 8S7/2. Both phosphors exhibited a broad excitation spectrum with a peak at 253 nm. The excitation and emission properties are thus adequate enough to obtain UVB light sources using a conventional high pressure mercury vapour lamp or an ultraviolet LED.

Efficacy of UVC-LED radiation in bacterial, viral, and protozoan inactivation: an assessment of the influence of exposure doses and water quality

Ultraviolet light-emitting diodes (UV-LEDs) have demonstrated the ability to inactivate microorganisms in water, offering an environmentally safer alternative to the conventional mercury lamp, in UV applications. While several studies have explored the microbiological effect of UVC-LEDs (200nm-280nm), limited information exists regarding their effects on waters with critical qualities. These critical qualities encompass bacteria, viruses, and protozoa – drinking water quality indicators defined by the World Health Organization for small water systems. For the first time, this work reports on the Escherichia coli, PhiX-174, MS2, and Cryptosporidium oocysts inactivation using a bench-scale UVC-LED (280 nm) water disinfection system. UV doses at a wavelength of 280 nm (UV280) of up to 143.4 mJ/cm2 were delivered under two quality-critical water conditions: filtered water (UV transmittance at 280 nm – UVT280 90.2 %) and WHO challenge water (UVT 15.7 %). Results revealed microbiological reductions dependent on exposure time and UVT. For UV280 dose of 16.1 mJ/cm2, 2.93-3.70 log E. coli reductions were observed in UVT 90.2 % and 15.7 %, 3.49-4.21 log for PhiX-174, 0.63-0.78 log for MS2, and 0.02-0.04 log for Cryptosporidium oocysts. Significantly higher UV280 doses of 143.4 mJ/cm2 led to reductions of 3.94-5.35 log for MS2 and 0.42-0.46 log for Cryptosporidium oocysts. Statistical analysis revealed that the sensitivity among the organisms to UV280 exposure was E. coli = PhiX-174 > MS2 >> Cryptosporidium oocysts. Although experiments with WHO challenge water posed greater challenges for achieving 1 log reduction compared to filtered water, this difference only proved statistically significant for PhiX-174 and MS2 reductions. Overall, UVC-LED technology demonstrated notable efficacy in microbiological inactivation, achieving significant reductions based on WHO scheme of evaluation for POU technologies in both bacteria and viruses even in critical-quality waters. The findings emphasize the potential for extending the application of UVC-LED as a viable solution for household water treatment.

On-Site Inactivation for Disinfection of Antibiotic-Resistant Bacteria in Hospital Effluent by UV and UV-LED.

The problem of antimicrobial resistance (AMR) is not limited to the medical field but is also becoming prevalent on a global scale in the environmental field. Environmental water pollution caused by the discharge of wastewater into aquatic environments has caused concern in the context of the sustainable development of modern society. However, there have been few studies focused on the treatment of hospital wastewater, and the potential consequences of this remain unknown. This study evaluated the efficacy of the inactivation of antimicrobial-resistant bacteria (AMRB) and antimicrobial resistance genes (AMRGs) in model wastewater treatment plant (WWTP) wastewater and hospital effluent based on direct ultraviolet (UV) light irradiation provided by a conventional mercury lamp with a peak wavelength of 254 nm and an ultraviolet light-emitting diode (UV-LED) with a peak emission of 280 nm under test conditions in which the irradiance of both was adjusted to the same intensity. The overall results indicated that both UV- and UV-LED-mediated disinfection effectively inactivated the AMRB in both wastewater types (>99.9% after 1-3 min of UV and 3 min of UV-LED treatment). Additionally, AMRGs were also removed (0.2-1.4 log10 for UV 254 nm and 0.1-1.3 log10 for UV 280 nm), and notably, there was no statistically significant decrease (p < 0.05) in the AMRGs between the UV and UV-LED treatments. The results of this study highlight the importance of utilizing a local inactivation treatment directly for wastewater generated by a hospital prior to its flow into a WWTP as sewage. Although additional disinfection treatment at the WWTP is likely necessary to remove the entire quantity of AMRB and AMRGs, the present study contributes to a significant reduction in the loads of WWTP and urgent prevention of the spread of infectious diseases, thus alleviating the potential threat to the environment and human health risks associated with AMR problems.

Evaluating the Diagnostic Accuracy of a Portable, Motorized, and Remotely Controlled Slit Lamp Imaging Adaptor Prototype for Head-Mounted Displays.

The purpose of this study was to validate the performance of a portable and remotely controlled slit lamp imaging adaptor. Twenty patients with anterior eye segment conditions participated in a randomized masked clinical trial. Imaging was performed using a Haag-Streit AG, BX 900 slit lamp biomicroscope and a new slit lamp prototype. Three ophthalmologists independently reviewed masked and randomized 2D images from both instruments and conducted physical eye examinations based on these images. Inter- and intra-grader reliability were assessed using kappa statistics, and sensitivity and specificity were determined with reference to the clinical eye examinations performed during the patients' visits. The sensitivity and specificity of the evaluations with the prototype were 47.8% and 64.1%. Similarly, the evaluations from the conventional system obtained a sensitivity and specificity of 49.5% and 66.2%. The differences in the sensitivity and specificity between imaging modalities were not statistically significant (P > 0.05). The intra-grader reliability showed moderate to substantial agreement between the systems (κ = 0.522-0.708). The inter-grader reliability also indicated moderate agreement for the evaluations with the conventional system (κ = 0.552) and the prototype (κ = 0.474). This study presents a new prototype that exhibits diagnostic accuracy on par with conventional slit lamps and moderate reliability. Further studies with larger sample sizes are required to characterize the prototype's performance. However, its remote functionality and accessibility suggest the potential to extend eye care. The development of portable and remotely controlled eye imaging systems will enhance teleophthalmology services and broaden access to eye care at the primary care level.

Performance of high-efficiency UV-C LEDs in water disinfection: Experimental, life cycle assessment, and economic analysis of different operational scenarios

The widespread use of low or medium pressure mercury lamps in UV-C water disinfection should consider recent advances in UV-C LED lamps that offer a more sustainable approach and avoid its main drawbacks. The type of water and the mode of operation are critical when deciding on the treatment technology to be used. Therefore, this study investigates the potential application of UV-C LED disinfection technology in terms of kinetics, environmental assessment, and economic analysis for two scenarios: the continuous disinfection of a wastewater treatment plant (WWTP), and disinfection of harvested rainwater (RWH) in a residential household that operates intermittently. Experiments are conducted using both the new UV-C LED system and the conventional mercury lamp to disinfect real wastewater. Removal of total coliforms and Escherichia coli bacteria, with concentrations of approximately 105 and 104 CFU per 100 mL has been followed to assess the performance of both types of UV-C lamps. The experimental study provides kinetic parameters that have been further used in the environmental assessment conducted from a life cycle perspective. Additionally, considering the significant role of electricity consumption, a preliminary economic analysis has been conducted. The results indicate that first-order kinetic constants of pathogens removal with UV-C LEDs achieve 1.4 times higher values than Hg lamp. Regarding the environmental and economic assessment, for disinfection systems operating continuously, LEDs result in environmental impacts 5 times higher than Hg lamp in most categories, indicating that Hg lamps offer a viable option both from economic and environmental point of view. However, for installations with intermittent operation, LEDs emerge as the most competitive alternative, due to their ability to be turned on and off without affecting their lifespan. This study shows that UV-C LED lamps hold promise to replace conventional mercury lamps in a near future.

Comparative Evaluation of PCR-Based, LAMP and RPA-CRISPR/Cas12a Assays for the Rapid Detection of Diaporthe aspalathi.

Southern stem canker (SSC) of soybean, attributable to the fungal pathogen Diaporthe aspalathi, results in considerable losses of soybean in the field and has damaged production in several of the main soybean-producing countries worldwide. Early and precise identification of the causal pathogen is imperative for effective disease management. In this study, we performed an RPA-CRISPR/Cas12a, as well as LAMP, PCR and real-time PCR assays to verify and compare their sensitivity, specificity and simplicity and the practicality of the reactions. We screened crRNAs targeting a specific single-copy gene, and optimized the reagent concentrations, incubation temperatures and times for the conventional PCR, real-time PCR, LAMP, RPA and Cas12a cleavage stages for the detection of D. aspalathi. In comparison with the PCR-based assays, two thermostatic detection technologies, LAMP and RPA-CRISPR/Cas12a, led to higher specificity and sensitivity. The sensitivity of the LAMP assay could reach 0.01 ng μL-1 genomic DNA, and was 10 times more sensitive than real-time PCR (0.1 ng μL-1) and 100 times more sensitive than conventional PCR assay (1.0 ng μL-1); the reaction was completed within 1 h. The sensitivity of the RPA-CRISPR/Cas12a assay reached 0.1 ng μL-1 genomic DNA, and was 10 times more sensitive than conventional PCR (1.0 ng μL-1), with a 30 min reaction time. Furthermore, the feasibility of the two thermostatic methods was validated using infected soybean leaf and seeding samples. The rapid, visual one-pot detection assay developed could be operated by non-expert personnel without specialized equipment. This study provides a valuable diagnostic platform for the on-site detection of SSC or for use in resource-limited areas.

Performance evaluation of loop-mediated isothermal amplification, polymerase chain reaction and real-time polymerase chain reaction methods to detect Neisseria gonorrhoeae among symptomatic patients from India.

Background: Neisseria gonorrhoeae is one of the most important causative organisms in causing sexually transmitted infections. The clinical presentation of gonorrhoea mimics the symptoms of other sexually transmitted infections, and a proper diagnosis of the same is therefore crucial in patient management. The current study intended to compare different in-house molecular methods: that is, conventional PCR, real-time PCR, and LAMP assay for detection of N. gonorrhoeae. Methods: A total of 163 samples were collected from 145 patients who presented with urethral and vaginal discharge. Collected samples were processed for culture on GC agar base, and three different molecular diagnostic tests (conventional PCR, real-time PCR, and LAMP assay) were performed simultaneously on all the samples. Results: Culture of N. gonorrhoeae was positive in 17 out of 21 (80.9%) swab samples. With culture as the gold standard method, conventional and real-time PCR had a sensitivity of 94.1%, whereas the sensitivity of the LAMP assay was found to be 88.2%. All three methods had a specificity of 100%. In addition to swab samples, evaluation of urine samples by different molecular methods yielded a good concordance with a kappa value of 0.85 by conventional PCR and real-time PCR showing a perfect level of agreement, while the LAMP assay was found to have a substantial level of agreement. Conclusion: LAMP assay had a comparable diagnostic accuracy to other molecular methods for the detection of N. gonorrhoeae and can be used as a point-of-care test in resource-limited settings.

A simple and economic method to modify large organic surfaces for enhancing adhesion and transparent Au/PMMA with high electromagnetic shielding efficiency

This study introduces a simple and cost-effective approach for modifying large organic surfaces, facilitating robust adhesion between Au films and polymethyl methacrylate (PMMA) while retaining transparency to visible light and effectively shielding against electromagnetic interference (EMI). The proposed surface modification method employs a cheap low-power conventional UV lamp to illuminate organic surfaces in an open environment, rending it convenient and applicable for surfaces ranging from small to massive, irrespective of size, shape and location. By subjecting transparent PMMA glass to a brief 20–30 min exposure to a 36 W UV lamp positioned 5 cm away from the sample surface, the PMMA surface is dramatically modified and the surface is turned from hydrophobic to hydrophilic, establishing a strong adhesion between PMMA and Au films. The resulting Au/PMMA glass exhibits remarkable transparency about 70% within the visible light spectrum, coupled with an impressive EMI shielding efficiency that surpasses 20 dB across a broad range of electromagnetic wavebands, encompassing the S, C, X and Ku bands that correspond to the wave frequencies of major electromagnetic pollution and crucial applications of 5G communication, credit card validation, radar systems, traffic control, etc. Various characterizations have been conducted, elucidating the underlying mechanisms. This study presents an important advancement, and the accessible and scalable nature of the large-scalable surface modification method has far-reaching implications across numerous industrial sectors and applications, in addition to transparent EMI shielding Au/PMMA glasses.

Surface Illumination as a Factor Influencing the Efficacy of Defect Recognition on a Rolled Metal Surface Using a Deep Neural Network

Modern neural networks have made great strides in recognising objects in images and are widely used in defect detection. However, the output of a neural network strongly depends on both the training dataset and the conditions under which the image was acquired for analysis. We have developed a software–hardware method for evaluating the effect of variable lighting on the results of defect recognition using a neural network model. The proposed approach allows us to analyse the recognition results of an existing neural network model and identify the optimal range of illumination at which the desired defects are recognised most consistently. For this purpose, we analysed the variability in quantitative parameters (area and orientation) of damage obtained at different degrees of illumination for two different light sources: LED and conventional incandescent lamps. We calculated each image’s average illuminance and quantitative parameters of recognised defects. Each set of parameters represents the results of defect recognition for a particular illuminance level of a given light source. The proposed approach allows the results obtained using different light sources and illumination levels to be compared and the optimal source type/illuminance level to be figured out. This makes implementing a defect detection environment that allows the best recognition accuracy and the most controlled product quality possible. An analysis of a steel sheet surface showed that the best recognition result was achieved at an illuminance of ~200 lx. An illuminance of less than ~150 lx does not allow most defects to be recognised, whereas an illuminance larger than ~250 lx increases the number of small objects that are falsely recognised as defects.

Assessing public street lighting in Morocco: evaluating efficiency and the impact of geometrical parameters on luminance

The main objective of this study is to present a bench marking of the public street lighting in typical road in Morocco. The study deals with a comparison between the conventional technology used in Moroccan road and the LED technology. The simulated system is based on road with two directions and a sidewalk, three arrangements type of pole layout are treated (Left, Middle and Two sides arrangement). Also, in this paper deals with a parametric analysis based on the variation of boom angle, light Center high and the pole distance in order to determine the luminance of each arrangement at each pole distance. The simulation is carried out using two luminaries, the fi rst one represents a conventional technology and LED lamp. The founding of this paper shows that the LED lamp present a high luminance value of 20 cd/m² for a pole distance of 10m and boom angle of 0°, in comparison with the conventional lamp that present a luminance of 8 cd/m² at the same condition. The left arrangement type shows the best energy effi ciency indicators such as DE and power per km, this means that this disposition is less consuming of energy and acceptable luminance values. Therefore, these two indicators play a crucial role in enhancing the effi ciency of the lighting.

Feasibility of Tear Meniscus Height Measurements Obtained with a Smartphone-Attachable Portable Device and Agreement of the Results with Standard Slit Lamp Examination

Purpose: We aimed to evaluate the feasibility of using a novel device, the Smart Eye Camera (SEC), for assessing tear meniscus height (TMH) after fluorescein staining and the agreement of the results with measurements obtained using standard slit lamp examination. Methods: TMH was assessed using both SEC and conventional slit lamp examination. The images were analyzed using the software ImageJ 1.53t (National Institutes of Health, Bethesda, MD, USA). A common measurement unit scale was established based on a paper strip, which was used as a calibration marker to convert pixels into metric scale. A color threshold was applied using uniform parameters for brightness, saturation, and hue. The images were then binarized to black and white to enhance the representation of the tear menisci. A 2 mm area around the upper and lower meniscus in the central eye lid zone was selected and magnified 3200 times to facilitate manual measurement. The values obtained using SEC were compared with those obtained with a slit lamp. Results: The upper and lower TMH values measured using the SEC were not statistically different from those obtained with a slit lamp (0.209 ± 0.073 mm vs. 0.235 ± 0.085, p = 0.073, and 0.297 ± 0.168 vs. 0.260 ± 0.173, p = 0.275, respectively). The results of Bland–Altman analysis demonstrated strong agreement between the two instruments, with a mean bias of −0.016 mm (agreement limits: −0.117 to 0.145 mm) for upper TMH and 0.031 mm (agreement limits: −0.306 to 0.368 mm) for lower TMH. Conclusions: The SEC demonstrated sufficient validity and reliability for assessing TMH in healthy eyes in a clinical setting, demonstrating concordance with the conventional slit lamp examination.

Sustainable Photocatalytic Acylation of Transition Metal Dichalcogenides with Atom Economy.

Transition metal dichalcogenides (TMDs) are promising 2D nanomaterials for diverse applications, but their intrinsic chemical inertness hinders their modification. Herein, a novel approach is presented for the photocatalytic acylation of 2H-MoS2 and 2H-MoSe2, utilizing tetrabutyl ammonium decatungstate ((nBu4N)4W10O32) polyoxometalate complex as a catalyst and a conventional halogen lamp as a source of irradiation. By harnessing the semiconducting properties of TMDs, new avenues emerge for the functionalization of these materials. This novel photocatalytic protocol constitutes the first report on the chemical modification of 2D nanomaterials based on a catalytic protocol and applies to both aliphatic and aromatic substrates. The scope of the decatungstate-photocatalyzed acylation reaction of TMDs is explored by employing an alkyl and an aromatic aldehyde and the success of the methodology is confirmed by diverse spectroscopic, thermal, microscopy imaging, and redox techniques. This catalytic approach on modifying 2D nanomaterials introduces the principles of atom economy in a functionalization protocol for TMDs. It marks a transformative shift toward more sustainable and efficient methodologies in the realm of TMD modification and nanomaterial chemistry.

Novel point-of-care rapid detection of monkeypox virus.

Monkeypox, a viral zoonotic disease caused by MPXV, has emerged as a significant global health concern since the first outbreak outside Africa in 2003. As of the current data, there have been 30 189 confirmed cases of monkeypox in 88 countries, with 29 844 cases reported in 81 countries. Given the absence of prior documented instances of the disease, swift and accurate testing is imperative to contain the spread of monkeypox. In this study, we developed a LAMP detection reagent for monkeypox and evaluated its performance in terms of sensitivity, specificity, repeatability, stability, linear range, and linearity, utilizing a commercial magnetic bead-based nucleic acid extraction system. This has led to the establishment of an integrated on-site detection platform for the monkeypox virus, utilizing a closed cartridge. The sensitivity was found to be 100 copies per μL, with no cross-reactivity observed with three other viruses, indicating robust performance. The parameters of repeatability, stability, linear range, and linearity were also assessed. For 28 simulated samples, the detection results obtained from the integrated system were consistent with those from conventional laboratory methods, specifically qPCR and LAMP detection following nucleic acid extraction. The entire process can be completed in approximately one hour, making it highly suitable for immediate rapid testing.

Fraunhofer line-based wavelength-calibration method without calibration targets for planetary lander instruments

High-accuracy wavelength calibration is critical for qualitative and quantitative spectroscopic measurements. Many spectrometers employed in planetary-exploration missions have onboard calibration sources, including standard lamps and calibration targets. However, such calibration sources are not always available because planetary missions, particularly landing missions, usually have limitations in size and mass. Thus, a wavelength calibration method without requiring hardware addition can be highly beneficial. In this study, we demonstrate a method for wavelength calibration using solar Fraunhofer lines observed in the reflectance spectra of planetary surfaces. Using a Raman spectrometer prototype developed for a Phobos rover, we measured the spectrum of the sunlight reflected from a spectral standard, manufactured to provide similar reflectance spectra to the surface of Phobos. We identified 35 Fraunhofer absorption lines in the wavelength range between 530 and 700 nm and utilized these features for the wavelength calibration of the spectrometer. This approach using Fraunhofer lines achieved good results (better than +0.04/−0.06 nm), comparable to the results achieved using a conventional Ne lamp. The wavelength accuracy corresponds to a wavenumber accuracy better than ±1.5 cm−1 in the 0–4000 cm−1 Raman shift (Stokes shift) range with a 532 nm excitation laser. This result enabled the estimation of the magnesium number (Mg#) of olivine, achieving a value more precise than 1.5% based on the Raman peak positions. In addition, we examined the number of solar Fraunhofer lines detectable at different wavelength resolutions by binning the solar spectrum acquired in this study. We found that more than 10 Fraunhofer lines could be detected as prominent absorption lines when the wavelength resolution is higher than 1 nm/pix (30 cm−1/pix at 1000 cm−1). This result suggests that the target-free wavelength-calibration method using solar Fraunhofer lines can be applied to other spectrometers simply by observing sunlit planetary surfaces.

Sensitization of TiO2 NPs with curcumin and chlorella and photocatalytic performance for degradation of phenol and organic dyes

Titanium dioxide (TiO2) is the most used semiconductor for heterogeneous photocatalysis. However, there is a limitation to its use because it is only activated under ultraviolet radiation (below 390 nm). Sunlight comprises only 5 % of UV radiation and consequently limits the use of TiO2 as a photocatalyst. Several studies were performed to extend the photocatalytic activity of TiO2 to the visible spectrum. Therefore, in this work two TiO2 NPs (S1 and P25) were sensitized with natural extracts to extend their photocatalytic activity to the visible light. In a previous work of our group TiO2 nanoparticles with a high surface area were synthesized via controlled precipitation method (called S1). In sequence they were wet sensitized with extracts of curcumin and Chlorella pyrenoidosa microalga to extend their photocatalytic activity to the visible light. After sensitization with natural extracts, the samples were characterized. The photoactivity of the NPs was evaluated for the degradation of phenol and the methylene blue, Rhodamine B and methyl orange dyes, under visible light using conventional LED lamps (380 to 780 nm). By XRD analysis all samples showed anatase and rutile as the only phases. The NPs sensitized with the highest content of chlorella and curcumin showed the highest mass loss (16 and 49 wt%, respectively), determined by DSC/TG, proving the adsorption of both extracts. Chemical bonds ascribed to both extracts were observed by the FTIR analysis. In addition, the NPs sensitized with the less content of the extracts presented the higher specific surface areas (∼207 m2/g, by BET analysis). The NPs are stable in water solution, presenting a zeta potential of −33 mV. Chlorella shows a larger absorption spectrum than curcumin. The calculated band gaps are 2.25 eV for chlorella and 2.07 eV for curcumin. Finally, the sensitization did not change the size or shape of the NPs (FESEM). The results of the photocatalytic activity tests show that the sensitized S1 NPs show higher efficiency than the commercial sensitized P25 NPs for the discoloration of the dyes, reaching 97 % for rhodamine B dye.

A Novel Integrated Electronic Lighting Driver Circuit for Supplying an LED Projection Lamp with High Power Factor and Soft Switching Characteristics

The traditional light source of projection lamps adopts a halogen lamp, which has the advantages of high brightness, but its luminous efficiency is not good and consumes energy. A light-emitting diode (LED) has the characteristics of high luminous efficiency and energy savings and can be used as a new light source for projection lamps. The conventional two-stage electronic lighting driver circuit for supplying an LED projection lamp is composed of an AC-DC converter with power factor correction (PFC) as the first stage and a DC-DC converter for providing rated lamp voltage and current as the second stage. The conventional LED projection lamp driver circuit has more circuit components, a higher cost and limited efficiency. Therefore, this paper proposes a novel electronic lighting driver circuit for supplying an LED projection lamp with PFC function, which integrates a modified stacked dual boost converter and a half-bridge LLC resonant converter into a single-stage power-conversion circuit. The inductor inside the modified stacked boost converter is designed to operate at discontinuous conduction mode (DCM) for the driver circuit achieving PFC. Wide bandgap semiconductor devices silicon carbide (SiC)-based Schottky diodes are utilized to reduce power diode losses, and soft switching is implemented in the proposed LED projector lamp driver circuit to reduce the switching losses of the power switches and thus improve circuit efficiency. This paper has completed a single-stage prototype driver circuit for an LED projection lamp with PFC function, and the prototype circuit has a high power factor (PF &gt; 0.98), low input current total-harmonic-distortion (THD &lt; 6%) and high efficiency (&gt;89%) in the case of an AC input power supply with an RMS value of 110 volts, and both power switches have the characteristics of soft switching.

Quantitative classification of melasma with photoacoustic microscopy: a pilot study.

The classification of melasma is critical for correct clinical diagnosis, treatment selection, and postoperative measures. However, preoperative quantitative determination of melasma type remains challenging using conventional Wood's lamp and optical dermoscopy techniques. Using photoacoustic microscopy (PAM) to simultaneously obtain the two diagnostic indicators of melanin and blood vessels for melasma classification and perform quantitative analysis to finally achieve accurate classification, rather than relying solely on physicians' experience. First, the patients were classified by experienced dermatologists with Wood's lamp and optical dermoscopy. Next, the patients were examined in vivo using the PAM imaging system. Further, the horizontal section images ( plane) of epidermal melanin and dermal vascular involvement were extracted from the 3D photoacoustic imaging results, which are important basis for PAM to quantitatively classify melasma. PAM can quantitatively reveal epidermal thickness and dermal vascular morphology in each case and obtain the quantitative diagnostic indicators of melanin and blood vessels. The mean vascular diameter in lesional skin () of epidermal M+V-type was much larger than that in non-lesional skin (), and the mean vascular density in lesional skin was more than three times that in non-lesional skin. Importantly, vascular diameter and density are important parameters for distinguishing M type from M+V type. PAM can obtain the data of epidermal thickness, pigment depth, subcutaneous vascular diameter, and vascular density, and realize the dual standard quantitative melasma classification by combining the parameters of melanin and blood vessels. In addition, PAM can provide new diagnostic information for uncertain melasma types and further refine the typing.

Mitigating the impacts of street lighting on biodiversity and ecosystem functioning.

Street lights are not only a major source of direct light pollution emissions, but stock has been transitioning to light-emitting diode (LED) technology in many parts of the world, resulting in increases in the blue part of the visible spectrum that is more harmful to biodiversity and human health. But LEDs can be modified more easily than conventional sodium lamps by adjusting their intensity, spectral output and other features of street light systems. In this Opinion piece, I provide an updated overview of street light mitigation strategies and contend that research in this area has been slow. I show how experimental lighting rigs that mimic real street lights can be used for mitigation testing, since invertebrate behaviour, abundances and interactions can respond quickly and measurably. I demonstrate how advances in network ecology that use species interaction data can provide much-needed assessments of the impacts of street lights on biodiversity and ecosystem functioning, and ultimately provide new tools and metrics for biomonitoring. I acknowledge the limitations of measuring local, short-term responses of biodiversity and identify promising avenues for collaborating with industry and government agencies in new or existing road lighting schemes, to minimize the negative long-term impacts at marginal cost. This article is part of the theme issue 'Light pollution in complex ecological systems'.