Light Bulb Research Articles

Exploring luminescent color tunability and efficient energy transfer mechanism of a single-phased hexagonal nanophosphor for white light emitting diodes (WLEDs) application

Nowadays, NUV-triggered phosphor-converted white light-emitting diodes (pc-WLEDs) have gained prominence as substantial alternatives to conventional incandescent and fluorescent lamps as a source of illumination. In this study, we have successfully developed a Tm3+ codoped La2O3:Sm3+ nanophosphor and investigated its potential suitability for application in white light-emitting diodes (WLEDs). X-ray diffraction (XRD) analysis was conducted to examine the phase impurity and structural characteristics of the synthesized nanophosphor. The analysis confirmed the formation of a single-phase La2O3 nanophosphor with a hexagonal crystal structure. The FT-IR spectrum of the synthesized nanophosphor exhibited distinct peaks associated with the vibrational frequencies of La-O bonds. The peaks observed in the fingerprint region of the spectrum, indicate the presence of La-O atoms in the nanophosphor. However, the HR-TEM analysis confirmed that the prepared nanophosphor had a polycrystalline nature and the observed particle sizes lay within the nanoscale range. The incorporation of Tm3+ ions into the host matrix led to a reduction in the optical band gap, leading to enhanced emission intensity. The photoluminescence (PL) study reveals that the Tm3+ ion exhibited blue emission upon excitation at 360 nm, whereas the Sm3+ ion emits reddish-orange light when excited at 379 nm and 408 nm, respectively. However, under 325 nm excitation, the nanophosphor exhibited a white emission color that resulted from the blending of colors emitted by both Tm3+ and Sm3+ ions. This unique finding suggests that this nanophosphor has the potential to generate white light specifically under this particular excitation wavelength. The efficient energy transfer between Tm3+ and Sm3+ ions was attributed to the electric multipolar interaction between the nearest neighbor ions, leading to a quenching phenomenon. Furthermore, the photometric analysis revealed that the correlated color temperatures (CCTs) associated with the emitted white light were found to be higher than 4000 K. Thus, based on these characteristics, it can be inferred that the prepared nanophosphor has the potential to be utilized as a cool white-emitting nanophosphor for single-phased WLEDs application.

Sistem Kontrol Lampu Dan Kipas Angin Dengan Google Assistant Berbasis IoT

Electricity usage in Indonesia has become an essential part of daily life, steadily increasing over the years. According to the Central Statistics Agency, per capita electricity consumption was 0.91 MWH in 2015, rising to 1.09 MWH in 2020. This upward trend can be curbed with technological advancements. In many buildings, lights and fans are manually controlled through switches. While suitable for small spaces, this method becomes inefficient and leads to energy wastage in larger buildings with multiple rooms, often going unnoticed. Additionally, the perception of electricity wastage varies among individuals, depending on their habits. To address this, a smart IoT-based system with Google Assistant control has been designed. The system employs NodeMCU ES8266 microcontroller, DHT11 sensors, 2-channel relay, USB fans, 5W light bulbs, Google Home, Google Assistant, and Sinric Pro. Tested in a black box scenario, the system achieved an accuracy rate of 83%. The DHT11 sensor exhibited a maximum error of 5% for temperature readings and 1% for humidity. The overall error for DHT11 sensor readings ranged from 13% to 8%.

ZnO nanoparticles with altered structural and optical traits by Cu and Li doping for elevated photocatalytic activity toward organic pollutants

Doping of copper and lithium on zinc oxide nanoparticles (NPs) has attracted a great deal of attention due to their morphological change, large surface-to-volume ratio, and enhanced physical properties. In this study, Cu-doped ZnO NPs (CZO) and Li-doped ZnO NPs (LZO) were synthesized by one-step hydrothermal method. The obtained nanostructures were characterized using analytical techniques such as XRD, UV-visible spectroscopy, FTIR, SEM, and TEM. The XRD analysis of CZO and LZO revealed hexagonal nanorod structures possessing a dominant peak at (101) hkl plane. From SEM imaging, it was observed that the doping concentration of Cu- and Li- onto the ZnO nanoparticles had an effect on the morphology and size of the obtained nanorods. EDAX analysis confirmed the presence of Cu and Li ions in the ZnO lattice structures. The photocatalytic degradation of CZO and LZO was performed using two dyes namely Rhodamine B and methylene orange under tungsten bulb light source. CZO and LZO showed a degradation of 56.51%0.61% and 63.97%% for Rhodamine B; 45.68%0.39% and 40.01%% of degradation was observed for methylene orange dye.

Diversity of gene expression responses to light quality in barley

Light quality influence on barley development is poorly understood. We exposed three barley genotypes with either sensitive or insensitive response to two light sources producing different light spectra, fluorescent bulbs, and metal halide lamps, keeping constant light intensity, duration, and temperature. Through RNA-seq, we identified the main genes and pathways involved in the genotypic responses. A first analysis identified genotypic differences in gene expression of development-related genes, including photoreceptors and flowering time genes. Genes from the vernalization pathway of light quality-sensitive genotypes were affected by fluorescent light. In particular, vernalization-related repressors reacted differently: HvVRN2 did not experience relevant changes, whereas HvOS2 expression increased under fluorescent light. To identify the genes primarily related to light quality responses, and avoid the confounding effect of plant developmental stage, genes influenced by development were masked in a second analysis. Quantitative expression levels of PPD-H1, which influenced HvVRN1 and HvFT1, explained genotypic differences in development. Upstream mechanisms (light signaling and circadian clock) were also altered, but no specific genes linking photoreceptors and the photoperiod pathway were identified. The variety of light-quality sensitivities reveals the presence of possible mechanisms of adaptation of winter and facultative barley to latitudinal variation in light quality, which deserves further research.

Sistem Informasi Suhu dan Kelembaban Inkubator Telur Ayam Menggunakan Sensor Dht22 Berbasis Mikrokontroler

Measurement of temperature and humidity generally uses a tool that can determine the value of two physical quantities of a material or system (thermometer or hygrometer). When it comes to hatchery incubators, success and protection are priorities. The microcontroller is a small computer in the form of a chip, DHT22 temperature and humidity sensor with a range of (-40)-80°C. Formulation of the problem, (1) How to get digital data of hatching incubator room temperature using a microcontroller? (2) How is the application of the system to hatching incubators?. Methods of research, analysis, implementation, and simulation (a) Analysis, the lowest ideal temperature for hatching eggs shows a figure of approximately 38°C and the highest is 38.5–39°C. (b) Implementation, starting with the use of DHT22 giving a temperature signal according to whether or not when the condition of the incandescent lamp as a heater will turn on or off, the display will be displayed on the LCD. (c) Simulation, the first stage is the DHT22 schematic to Arduino, the second stage is the relay schematic to Arduino, the third is I2C LCD to Arduino, the fourth is relay to lights and indicators. Based on the analysis, implementation and simulation, conclusions are drawn (1) Digital data related to temperature from the DHT22 sensor displayed on the LCD can be applied to help monitor the hatching process of chicken eggs using an incubator. (2) Arduino board-based microcontrollers can be applied as controllers related to system flow in chicken egg hatching incubators.

Design Of Electric Switching Systems For Electronic Equipment In Home Based Internet of Thing (IoT)

The tool for designing an IoT-based electronic equipment switch system has been designed. This system uses the NodeMCU ESP 8266 microcontroller where the NodeMCU ESP8266 functions as a data processor, and also as a receiver for wi-fi networks emitted by wi-fi network systems. This tool system uses a control system using an Android smartphone to turn on and off switches for electronic devices at home, this tool uses a Wi-Fi network communication system so that the device system and Android smartphone can be connected, in this tool system it uses a DC fan and incandescent lamps as outputs. connected to an electrical switch system, and the switch can turn on and turn off electronic devices on designed devices. The smartphone application used in this design is the Blynk application which can be downloaded at Playstore or Google.com. This tool is expected to help and facilitate humans in controlling electronic equipment at home both at home and when traveling.

Capacitance spectroscopy of InAs quantum dots inserted in an AlGaAs/GaAs HEMT for photodetector applications

We have investigated the electrical characteristics of an AlGaAs/GaAs high electron mobility transistor, in which a layer of InAs self-assembled Quantum Dots (QDs) was inserted below the 2DEG channel. A Negative Differential Capacitance (NDC) appeared in the capacitance–voltage characteristics at a bias of 1 V and at low temperatures (even at room temperature) under different illumination powers using white light bulbs. This results in an increase in negative differential conductance with the increase in frequency and optical power. This also applies to the NDC except that it decreases with increasing frequency. The numerical simulation of the energy band structure of the device confirmed that the conduction band lowers to its minimum at a special bias value of 1 V. The numerical analysis of the evolution of the energy levels in the QD-HEMT follows the appearance of multiple capacitance peaks and their behavior with the gate voltage.

A functional decision support system for management of Graphiola leaf spot (Graphiola phoenicis) disease during hardening of date palm tissue cultured plants in a greenhouse

A functional decision support system (DSS) was developed through optimising values of parameters favour faster growth and development of tissue cultured plantlets of date palm and suppression of disease infection. The programming of control devices was further managed based on the ambient environmental conditions, which required variable simulation periods and a plan for controlling of all systems for maintaining the greenhouse environment. During the process of plant hardening, the plants were infected by Graphiola leaf spot (Graphiola phoenicis). The moderate temperature, and high humidity inside the greenhouse, accompanied by short days and frequent occurrence of fog during winter months, favoured the development of smut infection. It is required to manage an extended photoperiod for 16 hours with 15000 lux light intensity provided by white fluorescent tube lights and incandescent bulbs inside the greenhouse. The integrated practices of enhanced photoperiod and light intensity under the greenhouse in combination with fungicides application to plants were found very effective in suppressing the intensity of the disease and its adverse effects on the plants. Using this decision support system (DSS), the tissue cultured date palm plants cv. Barhee has been successfully hardened and managed disease and transplanted in the field for further studying establishment, survival, plant growth and fruiting-related parameters.

Crank shaft road electromagnetic road energy harvester for smart city applications

This paper addresses the issue of providing cheap and on-demand electricity to low-power devices and sensors of smart cities and infrastructures. A new design for an electromagnetic road energy harvester is proposed, and its performance is evaluated through numerical simulations and experiments. The new method can generate sufficient electricity to run the low-power facilities of the smart cities in real-time and provide enough power for further applications using energy storage devices. Unlike the current road energy harvesters, the new harvester has a compact design, negligible mismatch risk between the components, and is more compatible with high-speed roadways. It can be used as road rumbles, transverse rumbles, or smooth speed bumps with a minimal vertical displacement of a maximum of 25 mm. It is shown that the harvester can illuminate LED light bulbs of 2 W at a displacement of 18 mm, which is compatible with the required depth of road rumbles. This power generation level satisfies sensors and IoT requirements and can also be stored for large-scale applications.

P23 Curing the nail

Abstract Introduction Ultraviolet light is a well known trigger for inducing cutaneous flares in people who are predisposed or have been diagnosed with cutaneous lupus, it may have far reaching implications, triggering organ threatening disease Ultraviolet light could be from various sources including the sun, light bulbs and drying lamps used in nail salons to “cure the nails”. Curing the nails is a term used in the manicure world where UVA type 2 light is used to facilitate complete and quick drying of the nail polish: these type of UV light have been implicated in the pathogenesis of lupus. Case description This is the case of a 41 year old lady of African descent diagnosed with discoid lupus at the age of 33. Symptoms include hair loss, hypopigmented lesions on her ear, urticarial rash, fatigue, joint stiffness. Prior history of pregnancy loss at 14 weeks noted, and her sister also suffers from lupus. On examination she was found to have scarring alopecia with hyperkeratotic erythematous lesions at the periungual area with acrylic nails. Blood work showed lymphopenia, positive ANA, positive dsDNA by ELISA, RO+, positive anti smith antibody, normal complements and no evidence of kidney involvement. She was treated with topical therapy and then escalated in turns to hydroxychloroquine, mycophenolate mofetil, azathioprine, rituximab and methotrexate. She had developed a rash on hydroxychloroquine leading to it's discontinuation. The periungual lesions were resistant to all of the above treatment including intralesional steroid. She had recurrent flares of the lesions which resulted in episodes of infection, pus drainage, and treatment with antibiotics. Nifedipine was introduced but did not ameliorate symptoms A causal link was eventually made between her exposure to UV light at the nail salon and the periungual lesion. She was advised to discontinue using the UV light and possibly resort to traditional nail polish and air drying. The periungual lesions significantly improved on cessation of using the UV lights. Discussion Gel/acrylic manicures are becoming increasingly popular as they are more aesthetically pleasing and long lasting compared to traditional nail polish which uses air drying method, however we should be aware of the risk of ultraviolet (UV) light exposure which is used to dry the nails. UV light stimulates keratinocytes to express more small nuclear ribonucleoproteins thereby secreting IL-1,1L-6, IL-3, GM-CSF which lead to tissue damage and increased autoantibody production, this can result in development of cutaneous lupus, worsening of cutaneous lupus or in some cases can precipitate organ threatening systemic lupus. As clinicians we should be aware of the risks and educate our patients on the implication to their disease, they should be encouraged not to use this method of manicure but rather resort to the traditional nail polish which uses air drying technique rather than UV light. Other options may include applying sun protection cream to the fingers before manicure or the use of UV protective gloves, these measures though may not provide adequate coverage to the periungual area. We should be aware and educate our patients on avoidance of other sources of UV light including avoidance of fluorescent light, tanning beds, surgical lamps and measures to reduce exposure. Key learning points Consider other sources of UV light exposure in patients with hard to treat skin disease. It is critical that we educate our patients on the possible side effects of UV exposure and counsel on strategies to minimise exposure

Performance study of an improved version of li-fi and wi-fi networks

With the increasing demand and need for telecommunication technologies, wireless communication has become a heavily useful and widely popular utility. Capacity, availability, efficiency, and security are issues generally linked to wireless communications, more specifically Wi-Fi systems. Yet we can exploit billions of light bulbs, which we use anywhere and everywhere on a daily basis and of which the infrastructure is already part of our ordinary life. This study focuses on Li-Fi theory and practices. The purpose of this paper is to demonstrate how these light sources can be used as a transmitter or, to be more precise, as an access point. This idea was proposed for the first time by Prof. Harald Hass in Global TED (2011). During the last two years, Li-Fi technology has been enhanced and improved by many professional and international studies. As new wireless communication technology develops to use LED, the efficiency, availability, security, and safety of light fidelity transform today’s telecommunication into tomorrow’s visible light communication.

Evaluation of the solar-powered Silver Bullet 2.1 (Lumin 8) light trap for sampling malaria vectors in western Kenya

BackgroundCenters for Disease Control and Prevention (CDC) light traps are widely used for sampling mosquitoes. However, this trap, manufactured in the USA, poses challenges for use in sub-Saharan Africa due to procurement costs and shipping time. Traps that are equally efficient than the CDC light trap, but which are amenable for use in remote African settings and made in Africa, are desirable to improve local vector surveillance. This study evaluated a novel solar-powered light trap made in South Africa (Silver Bullet trap; SB), for its efficiency in malaria vector sampling in western Kenya.MethodsLarge cage (173.7 m3) experiments and field evaluations were conducted to compare the CDC-incandescent light trap (CDC-iLT), CDC-UV fluorescent tube light trap (CDC-UV), SB with white diodes (SB-White) and SB with UV diodes (SB-UV) for sampling Anopheles mosquitoes. Field assessments were done indoors and outdoors following a Latin square design. The wavelengths and absolute spectral irradiance of traps were compared using spectrometry.ResultsThe odds of catching a released Anopheles in the large cage experiments with the SB-UV under ambient conditions in the presence of a CDC-iLT in the same system was three times higher than what would have been expected when the two traps were equally attractive (odds ratio (OR) 3.2, 95% confidence interval CI 2.8–3.7, P < 0.01)). However, when the white light diode was used in the SB trap, it could not compete with the CDC-iLT (OR 0.56, 95% CI 0.48–0.66, p < 0.01) when the two traps were provided as choices in a closed system. In the field, the CDC and Silver Bullet traps were equally effective in mosquito sampling. Irrespective of manufacturer, traps emitting UV light performed better than white or incandescent light for indoor sampling, collecting two times more Anopheles funestus sensu lato (s.l.) (RR 2.5; 95% CI 1.7–3.8) and Anopheles gambiae s.l. (RR 2.5; 95% 1.7–3.6). Outdoor collections were lower than indoor collections and similar for all light sources and traps.ConclusionsThe solar-powered SB trap compared well with the CDC trap in the field and presents a promising new surveillance device especially when charging on mains electricity is challenging in remote settings.

Alternatives to incandescent bulbs in Berlese funnels for detecting stored-product beetles in grain

We conducted a study to find alternative bulbs to use with Berlese funnels as a replacement for incandescent bulbs following widespread bans on their production and use. To do this, we measured the mean percent-recovery of adults and larvae of common stored-product beetles from 1-kg samples of wheat (12.5–14.5% moisture content) after 6 h using A19-style halogen bulbs and ceramic heat lamps, and compared them to recoveries using incandescent bulbs. We found that the 72W halogen bulb performed similarly to the incandescent bulb for all four species tested. Using this bulb, we recovered, on average, >85% of adult Cryptolestes ferrugineus, Rhyzopertha dominica, and adult and larval Tribolium castaneum, as well as >70% of adult Sitophilus oryzae. Recovery of adult beetles using the heat lamp was similar to the incandescent bulb, but recovery of larval T. castaneum was significantly lower. The 43W and 53W halogens had significantly lower recovery rates compared to the incandescent bulb for adult C. ferrugineus (both bulbs) and adult and larval T. castaneum (43W halogen). Average recovery of larval C. ferrugineus was low for all bulbs (<70%). Grain moisture content did not influence average recovery across species or life stages. We also investigated whether an operating time shorter than 6 h could be used with an alternative bulb, but found that 6 h was still the minimum time required to maximize adult and larval recovery. We recommend using 72W A19 style halogen bulbs in place of incandescent bulbs because they have similar recovery rates as the incandescent bulb, and are cost-effective compared to ceramic heat lamps. However, some systems may not be able to handle the increase in power consumption and so we suggest assessing the system before running a full bank of lights.

Experimental Complex for Spectral Diagnostics of Particle Flow Temperature during Gas-Thermal Spraying

The paper presents an instrumental diagnostic complex developed by the authors. The compact LR1 spectrometer for spectral diagnostics of particle temperature of two-phase flow is an integral part of the complex, as well as the calibration tool with the reference emitter. Additionally, a special emitter consisting of miniature light bulbs attached closely to each other was used in test experiments. This special emitter served as a simulation model of particle thermal radiation of gas-thermal flow used for spraying of functional coatings on technical products. The program-controlled adjustment of current flow through bulbs interconnected in different configurations yields a variety of simulated test histograms of the temperature distribution of the bulbs that correspond to actual particle temperature distribution histograms. The emitter with light bulbs has been used as a simulation model to confirm the validity of the physical and mathematical model of the integral (total) spectrum of particle thermal radiation for the proposed experimental spectrum registration method employing the LR1 spectrometer.

Forget-Me-Not: The Persistent Effect of Information Provision for Adopting Climate-Friendly Goods

It is well documented that people have misperceptions about energy costs. However, there is mixed empirical evidence about the effectiveness of information provision and its persistence over time. Understanding the interplay between information regarding the private and social benefits of low-carbon technologies and identifying mechanisms through which information treatments affect people’s long-term behaviors can help reconcile the mixed findings in the literature. In this paper, we measured the long-term effects of information provision through online experiments involving more than 3,000 households in China. We provided people with information on low-carbon light bulbs’ monetary and climate benefits and observed their purchasing decisions over 10 months. We find that information on private or social benefits leads to a temporary effect on most households and a persistent one on the uninformed. This evidence suggests that information provision works through two different mechanisms: increasing saliency and filling the information gap. This paper was accepted by Yan Chen, behavioral economics and decision analysis. Funding: Y. Gao received financial support from the National Natural Science Foundation of China [Grant 71903006]. M. Tavoni received financial support from the FP7 Ideas: European Research Council [Grant ERC-336155–COBHAM]. Supplemental Material: The data files and online appendix are available at https://doi.org/10.1287/mnsc.2023.4910 .

Application of Plant Microbial Fuel Cell (Pmfc) to Agricultural Industry in Contribution to Green Energy

Most of the innovation used by humans depends on electricity, thus becoming a crucial necessity. It enables people to live harmoniously and comfortably with the help of electricity which gives life to human inventions. Without electricity, most human inventions would be useless or nonexistent. Microbial Fuel Cell was conducted to test the efficiency of the generated current of microbes living inside the wet lands. By the use of the existing MFC series circuits, the researchers found out that there is an enough current that the MFC generated through electrodes (Zinc and Copper). The present study experimentally investigated the efficiency of generated current in MFC enough to power up low electronic materials such as: LED Light bulbs and Ditrio LED Lights. The farm lands will serve as the main source of electricity where the sludges will be taken and gathered to create a series circuit composed of two different prototypes.The global need for energy is always rising. In this case, carbon-based fuels have in one way or another provided for a significant share of the total energy requirement. As a result, fossil fuel resources have been severely depleted, which is now contributing to an ecological imbalance. Additionally, the burning of fossil fuels produces a significant amount of carbon dioxide, a significant greenhouse gas that has severe effects on the climate. MFC Systems or Microbial Fuel Cells Systems is a set of technology that uses microorganism as catalysts to oxidize organic and inorganic matter and generate current. Basically, wastewater such as sludge could carry these bacteria so it would be suspended to the system to generate current. It works as a battery where stacking multiple MFCs would create a higher voltage enough to power a household (Chaturvedi, Bioresources &amp; Bioprocessing, 2016). This allows bacteria to facilitate in electron transfer processes as the propose application of Plant Microbial Fuel Cell to Agricultural industry especially in farmlands is to assess the feasibility as potential source of electricity. The MFC system in farmlands may serve as an additional source of renewable green energy in contribution to fight against climate change.

Technical-economic prospect for photovoltaic on fixed lift net in Indonesia

The limited fossil energy and uncertain prices have an indirect effect on fishing activities using a fixed lift net. Therefore, energy diversification is carried out by utilizing solar energy with photovoltaics on the fixed lift net. This energy is very abundant and available throughout the year, except during the rainy season. This study uses observation, interviews, and questionnaires given to fishermen and tries to compare the utilization of photovoltaic (PV) systems with generators using different types of lamps, such as LED, CFL, incandescent lamps, and halogen lamps. The use of PV systems in fixed lift nets from a technical and economic perspective allows it to be utilized in the long term. Based on the technical aspects, the PV system can produce 471.59 Wh per day. This technical result will be more profitable if the lamp used is a light emitting diode (LED) lamp. Meanwhile, from economic aspect, the use of electrical energy from a PV system is more profitable because it provides a lower operational value than a generator, and provides good net present value (NPV) and internal rate of return (IRR) values. This utilization is also supported by the good response from fishermen towards the energy produced and the ease of operation and maintenance of the PV system.

Sustainable energy transition and decision-making for enhancing the performance of building equipment in diverse climatic conditions

The utilization of renewable resources for energy generation holds paramount significance in ensuring substantial and enduring growth for every nation. Both developing and developed countries heavily rely on conventional energy sources like coal, petroleum, and natural gas in thermal power plants, resulting in significant environmental impact due to their emissions. This research culminates in the successful evaluation of alternative approaches to implement sustainable green structures using an innovative scientific technique. This research has effectively identified ten key challenges impeding operational efficiency in the construction industry. The application of the groundbreaking Analytical hierarchy process (AHP) technology facilitated the simultaneous ranking of the most optimal solutions. The precise assessment of numerous Energy Management equipment options for sustainable green buildings was achieved, highlighting the tool’s impartiality and neutrality in addressing Multiple Criteria Decision Making (MCDM) challenges. The ‘Roof-mounted Solar Photovoltaic (SPV)’ configuration consistently ranked first across all MCDM solution techniques examined in this study. This robust consensus underscores the significance of solar panels followed by biodiesel nanoparticles energy generation as the preferred choice. In conclusion, the impartiality of the tools used to address multi-criteria challenges in “greening building” projects empowers decision-makers within institutions to make informed investment choices. By considering the rankings generated by these tools, funding can be directed towards the most appropriate projects. Following prioritization, the alternatives are ranked as follows: Solar thermal setup > Installing sunshade devices > Light switches > Free cooling > Controlling the cooling & heating of spaces > Utilizing the chiller’s waste heat > Energy-efficient light bulbs > Electrical appliance energy efficiency ratings > Effective active space cooling solutions.

Two-color thermal imaging of the melt pool in powder-blown laser-directed energy deposition

This work demonstrates an experimental technique to image melt pool temperature fields with a commercial color camera for laser-directed energy deposition (L-DED) processes. The technique relies on two-color thermography to construct spatially-resolved temperature fields and is demonstrated on 316L stainless steel (SS) melt pools from solidus to near-boiling temperatures. This two-color thermal imaging system negates the need for a priori knowledge of melt pool emissivity or the camera’s view factor and was validated with a calibrated tungsten filament lamp between temperatures of 1220 K and 2850 K. In-situ temperature measurements are combined with ex-situ cross-sectional geometry to determine the material’s effective absorptivity and coefficient of temperature-dependent surface tension, which is responsible for Marangoni convection, in a multi-physics computational fluid dynamics (CFD) model. Measured peak melt pool temperatures are important for understanding the molten convection within the melt pool, and measured cooling rates can be related to the resulting part microstructure. Peak temperatures from 1750 K to 3000 K show that below the boiling point, temperature increases with increasing laser power density and decreases with increasing scanning velocity. Thermal images are used to estimate cooling rates in the melt pool tail, which increase with the ratio of scanning velocity to power. Our thermal imaging strategy will advance measurement science in L-DED processes by validating multi-physics CFD models, quantifying cooling rates, providing real-time feedback control, and allowing process mapping of critical melt pool behaviors.

Analysis of the results of laboratory tests of the system of automatic control of the illumination of the led light

The article discusses the results of experimental data on the response of a photoconverter under the influence of radiation reflected from the working surface of various light sources (LED light source, incandescent lamp, fluorescent lamp, natural light source - the sun). The results of mathematical planning by three-factor and two-factor experiments are presented. As a result of the tests, it was found that when calibrating the automatic illumination control system for an LED lamp, when creating the same illumination on the working surface, the illumination coefficient should be taken into account. If the working surface is additionally affected by a solar light source, then an illumination coefficient of 3.99 is taken to calculate the resulting output signal; for fluorescent lamps - 3.38; incandescent lamps - 1.71.