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Micro-stereolithography (μ SL) is an advanced additive manufacturing technique that enables the fabrication of highly precise microstructures with fine feature resolution. One of the primary challenges in μ SL is achieving and maintaining precise focus throughout the fabrication process. For the successful application of μ SL, it is essential to maintain the sample surface within a focal depth of several microns. Despite the growing interest in auto-focus devices, limited attention has been directed towards auto-focus systems in image-based auto-focus microscope systems for precision μ SL. To address this challenge, we propose an image-based auto-focus microscope system incorporating visual servo control. In the optical design, a transflective beam splitter is employed, allowing the laser beam to pass through for fabrication while reflecting the focused beam on the sample surface to the microscope and camera. Utilizing captured spot images and the Foucault knife-edge test, a deep learning-based laser spot image processing algorithm is developed to determine the focus position based on spot size and the number of spot pixels on both sides. Experimental results demonstrate that the proposed auto-focus system effectively determines the relative position of the focal point using the laser spot image and achieves auto-focusing through visual servo control. [ABSTRACT FROM AUTHOR]

A nanocomposite (NC) of polyaniline (Pani), polyvinyl pyrrolidone (PVP) and zinc sulfide (ZnS) nanoparticles (NP) was prepared using chemical coprecipitation and ex-situ casting procedures. ZnS NP were synthesized using the chemical coprecipitation technique in atmospheric air. The x-ray diffraction (XRD) scans indicated that the synthesized ZnS had a nanonature and fit the cubic zinc blended structure. We used an infrared pulsed laser to irradiate the Pani/PVP/ZnS NC samples with fluences ranging from 3 to18 J/cm2. The induced changes in the NC were investigated using the UV spectroscopy and International Commission on Illumination (CIE) color difference methodology. When the laser fluence increased up to 18 J/cm2 both the direct and indirect optical bandgaps (Eg) decreased. Additionally, we used the optical dielectric loss (ε") to detect the type of microelectronic transition for the NC samples. The Eg of the exposed NC samples and the pristine samples exhibited indirect allowed transitions. The laser effects on the absorbance, extinction coefficient, transmission, refractive index, dielectric parameters and optical conductivity of the NC were studied. Lastly, the color differences between the pristine and exposed samples were determined. The pristine Pani/PVP/ZnS showed a significant color difference with the laser irradiated samples. The changes of the studied optical parameters with the laser fluence indicated that the laser radiation represents a convenient tool that would allow the application of Pani/PVP/ZnS NC in optoelectronic devices. [ABSTRACT FROM AUTHOR]

Copyright of Informatics Control Measurement in Economy & Environment Protection / Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska is the property of Lublin University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The refractive index of a liquid serves as a fundamental parameter reflecting its composition, thereby enabling the determination of component concentrations in various fields such as chemical research, the food industry, and environmental monitoring. Traditional methods for refractive index (RI) measurement rely on light deflection angles at interfaces between the liquid and a material with a known refractive index. In this paper, the authors present a new differential refractometer for the highly sensitive measurement of RI differences between two liquid samples. Using a configuration with two cells equipped with flat parallel plates as measuring elements, the instrument facilitates accurate analysis. Namely, the sensor signals from both the solution and the solvent cuvette are generated simultaneously with one laser pulse, reducing the possible fluctuations in the laser radiation intensity. Our evaluation shows the high sensitivity of RI measurements < 7 × 10 − 6 ), so this differential refractometer can be proposed not only as a high-sensitivity sensing tool that can be used for mobile detection of nanoparticles in solution samples but also to determine the level of environmental nano-pollution using water (including rain, snow) samples from various natural as well as industrial sources, thus helping to solve some important environmental problems. [ABSTRACT FROM AUTHOR]

The review summarizes the progress achieved in the surface modification of NiTi shape memory alloys (SMAs) with laser and electron beams in terms of their compliance with the requirements for biomedical devices and implants. The main provisions of the standards regulating this area of activity are aggregated. The production routes for manufacturing bulk items from NiTi SMAs are described. Since the formation of surface alloys on NiTi SMAs is now an intensively growing area of research, the influence of additional alloying elements on their functional properties is also discussed. The common patterns of interaction of laser and electron radiation with NiTi SMAs are specified. The typical requirements for surface layer conditions and conventional methods for their modification are reported. The results of various laser processing methods, differing in energy parameters, atmospheres and beam scanning algorithms, are summarized. They include remelting, annealing, nitriding, shock peening, alloying and texturing. In addition, some data on the modification and alloying of the surface layers with high-current pulsed electron beams are integrated. Finally, the aggregated information is compared and analyzed from the point of view of its prospects in these research areas. [ABSTRACT FROM AUTHOR]

The aim of the work was to study the influence of biogenic metal nanoparticles on the growth characteristics and biosynthetic activity of the fungus Laricifomes officinalis, as well as the effects of photocatalytic activity of NPs after exposure to low-intensity laser radiation under deep cultivation conditions. Material and Methods. Traditional mycological methods, colloidal solutions of nanoparticles biogenic metals, and unique photobiological methods were used. The effect of light on the biosynthetic acti vity of L. officinalis was studied using low-intensity coherent monochromatic laser light with specified spectral and intensity characteristics. The experiment used water-based colloidal solutions of biogenic metals such as Fe, Mg and Ag, obtained by a patented method. Results. Treatment of the inoculum with colloidal solutions of nanoparticles of all used metals increased the growth of L. officinalis by 31–54%, while irradiation of the fungal inoculum with laser light in a medium with nanoparticles reduced the growth activity of the L. officinalis mycelium by 14.4– 22.6%. All nanoparticles suppressed the biosynthesis of extracellular polysaccharides, whereas treatment of the inoculum with colloidal solutions of FeNPs and MgNPs stimulated the synthesis of endopolysaccharides. At the same time, laser light irradiation in the presence of AgNPs increased the amount of endopolysaccharides, while FeNPs and MgNPs slightly inhibited their synthesis. Treatment of the inoculum with colloidal metal solutions and laser light affected the total phenolic content (TPC) in the mycelial mass. The highest TPC values in ethanol extracts with AgNPs and laser light irradiation were 97.31±3.7 mg of GAEs/g of dry mass. Conclusions. The research results gave ground to consider nanoparticles of biogenic metals (AgNPs, FeNPs, MgNPs) and low-intensity laser light as a promising regulators of the biosynthetic activity of L. officinalis in the biotechnology of its cultivation. [ABSTRACT FROM AUTHOR]

Today, tailored laser beams are rarely used and thus an opportunity to optimize existing or introduce new processes is missed. New methods of dynamic beam shaping have the potential to change that in future. This keynote paper deals with methods allowing a transient energy input into the workpiece at such time scales that the underlying interaction processes are guided towards the desired result. It shows principles, categorizes necessary system technology, and gives application examples to familiarize the reader with the topic. It postulates that time-scale-dependent coupling between transient energy input and addressed process features is key for achieving the optimum. [ABSTRACT FROM AUTHOR]

In this work, a closed loop control system is developed to optically localize and track micro-robots with high precision. These micro-robots (i.e., micro-conveyors) are in motion simultaneously across a smart surface.The developed method's primary objectives are to optimize their trajectories, avoid collisions between them, and control their position with micrometric resolution. This article presents and characterizes the tracking of a single micro-conveyor, and the method works similarly when multiple micro-robots move over the surface. Our tracking method starts with a scanning phase, where a 2D steering mirror, placed above the smart surface, reflects a laser beam toward the conveying surface seeking for the target. Localization occurs when this light beam reaches the micro-conveyor. By adding a retro-reflective element, that reflects the light in the same direction of the the incident light, onto the surface of the micro-conveyor, the light will be reflected towards a photodetector. Depending on the feedback from the photodetector, the steering mirror rotates to track the trajectory of the micro-conveyor. The tip-tilt angular values of the steering mirror allows the micro-conveyor position to be obtained via calibrated localization system. The aim of this work is to regulate the micro-conveyor, within a closed-loop control system, to reduce the positional error between the actual and desired position. The actual position value is measured in real-time application using our developed optical sensor. Results for tracking in the x-and y-axis have validated the proposed method, with an average tracking error less than 30 µm within a range 150 mm × 150 mm. [ABSTRACT FROM AUTHOR]

We report consistent ignition of high-pressure ( p f i l l > 20–30 bar) hydrogen-oxygen mixtures diluted with helium in two different combustion vessels, using an unfocused Nd:YAG laser. This corresponds to laser irradiances several orders of magnitude below the minimum ignition energies reported in the literature. This unusual phenomena has led us to try to measure the amount of laser radiation absorbed by the gas medium. By placing a mirror inside a cylindrical vessel and filling it up to 100 bar with He-H 2 or He-O 2 non-combustible mixtures, we obtain the pressure-dependent absorptivity of the combustible He-H 2 -O 2 mixture. We find no measurable absorption of the laser signal by the medium, for the overall pressure range, to the experimental apparatus sensitivity (about 1% of the laser irradiance). The exact mechanism for ignition remains henceforth unknown. One possibility could the creation of seed electrons created by autofocusing ionization of dust/impurities in the gas, but this has yet to be experimentally confirmed. • A non-focused laser Nd:YAG can ignite high-pressure He-H 2 -O 2 mixtures. • Laser ignition of high-pressure mixtures can occur without a macroscopic spark. • Mixtures of H 2 -O 2 and He-H 2 at 100 bar are transparent to a 1064 nm laser. • The seed electrons are possibly generated by ionization of solid microparticles. [ABSTRACT FROM AUTHOR]

The aim of the present study was measurement of the color properties as Hue degree, Saturation value, and Brightness value (HSB). Three samples of Sesame oil was exposure by laser )diod laser with wavelength 450 nm) with three times (0.5, 1.0 and 1.5 h) and three samples of sesame oil were irradiated by Gamma Rays with three dosses (2, 4, 8 kGy) and one sample without any treatment (control). The processing of an image starts with the transfer of the image to the Personal Computer, where the image analysis process is applied. After that, it is performed the segmentation to watermark determine if each pixel belongs to bottom, skin or color. The parameters obtained from each Sesame oil sample (in each image are the pixel number of lighter oil (Stage 1), of darker or sesame oil profile (Stage 2). Taking image of each Sesame oil samples, a total number of 6 parameters can be obtained.Color properties {Hue, Saturation and brightness (HSB)}, color component {Red, Green and Blue (RGB)} of sesame oil. The obtained results were showed that by increasing Gamma radiation doses and exposure time of Laser, Hue degree was increased, that mean the color of sesame oil may be improved to be less quality. While, Hue degree was decreased by increasing storage period. Also, by increasing Gamma radiation doses and exposure time of Laser, the value of saturation was decreasing, that means that the color of sesame oil may be improved to be high quality. Meanwhile, the value of saturation was decreased by increasing storage period. As well as, by increasing Gamma radiation doses, exposure time of Laser and by increasing storage period the value of brightness was decreasing. [ABSTRACT FROM AUTHOR]

This review considers the fundamental dynamic processes involved in the laser heating of metal nanoparticles and their subsequent cooling. Of particular interest are the absorption of laser energy by nanoparticles, the heating of a single nanoparticle or an ensemble thereof, and the dissipation of the energy of nanoparticles due to heat exchange with the environment. The goal is to consider the dependences and values of the temperatures of the nanoparticles and the environment, their time scales, and other parameters that describe these processes. Experimental results and analytical studies on the heating of single metal nanoparticles by laser pulses are discussed, including the laser thresholds for initiating subsequent photothermal processes, how temperature influences the optical properties, and the heating of gold nanoparticles by laser pulses. Experimental studies of the heating of an ensemble of nanoparticles and the results of an analytical study of the heating of an ensemble of nanoparticles and the environment by laser radiation are considered. Nanothermometry methods for nanoparticles under laser heating are considered, including changes in the refractive indices of metals and spectral thermometry of optical scattering of nanoparticles, Raman spectroscopy, the thermal distortion of the refractive index of an environment heated by a nanoparticle, and thermochemical phase transitions in lipid bilayers surrounding a heated nanoparticle. Understanding the sequence of events after radiation absorption and their time scales underlies many applications of nanoparticles. The application fields for the laser heating of nanoparticles are reviewed, including thermochemical reactions and selective nanophotothermolysis initiated in the environment by laser-heated nanoparticles, thermal radiation emission by nanoparticles and laser-induced incandescence, electron and ion emission of heated nanoparticles, and optothermal chemical catalysis. Applications of the laser heating of nanoparticles in laser nanomedicine are of particular interest. Significant emphasis is given to the proposed analytical approaches to modeling and calculating the heating processes under the action of a laser pulse on metal nanoparticles, taking into account the temperature dependences of the parameters. The proposed models can be used to estimate the parameters of lasers and nanoparticles in the various application fields for the laser heating of nanoparticles. HIGHLIGHTS: • Analytical modeling of heating of a single nanoparticle or an ensemble thereof by laser radiation. • Nanothermometry methods for nanoparticle heating by laser radiation. • Applications of laser heating of nanoparticles in nanomedicine, nanoparticle processing, catalysis, etc. [ABSTRACT FROM AUTHOR]

Polymer-based membranes represent an irreplaceable group of materials that can be applied in a wide range of key industrial areas, from packaging to high-end technologies. Increased selectivity to transport properties or the possibility of controlling membrane permeability by external stimuli represents a key issue in current material research. In this work, we present an unconventional approach with the introduction of silver nanoparticles (AgNPs) into membrane pores, by immobilising them onto the surface of polyethyleneterephthalate (PET) foil with subsequent physical modification by means of laser and plasma radiation prior to membrane preparation. Our results showed that the surface characteristics of AgNP-decorated PET (surface morphology, AgNP content, and depth profile) affected the distribution and concentration of AgNPs in subsequent ion-track membranes. We believe that the presented approach affecting the redistribution of AgNPs in the polymer volume may open up new possibilities for the preparation of metal nanoparticle-filled polymeric membranes. The presence of AgNPs on the pore walls can facilitate the grafting of stimuli-responsive molecules onto these active sites and may contribute to the development of intelligent membranes with controllable transport properties. [ABSTRACT FROM AUTHOR]

The effect of terahertz (THz) radiation has been studied in medicine. However, there is a lack of scientific information regarding its possible mutagenicity. Therefore, the present study aimed to assess the mutagenicity of 1.6 THz laser irradiation. The Ames test was conducted using five bacterial tester strains. The bacteria were subjected to (i) 1.6 THz laser irradiation at 3.8 mW/cm2 for 60 min using a tabletop THz pulse laser system, (ii) ultraviolet irradiation, (iii) treatment with positive control chemicals (positive control) or (iv) treatment with the solvent used in the positive control (negative control). After treatment, the bacterial suspensions were cultured on minimal glucose agar to determine the number of revertant colonies. In addition, the comet assay was performed using fibroblasts (V79) to assess possible DNA damage caused by the THz laser irradiation. The Ames test demonstrated that the THz laser irradiation did not increase the number of revertant colonies compared to that in the negative control group, whereas the ultraviolet irradiation and positive control treatment increased the number of revertant colonies. Thus, 1.6 THz laser irradiation is unlikely to be mutagenic. The comet assay additionally suggests that the THz laser irradiation unlikely induce cellular DNA damage. [ABSTRACT FROM AUTHOR]

The prethreshold processes on the surface of copper and its alloys are investigated. In the absence of obvious traces of melting, while preserving the metal in a condensed state, under a nanosecond ultraviolet laser radiation energy density of 0.1–1.0 J/cm2, manifestations of high-temperature plastic deformation were observed. These are sliding and cracking along grain boundaries, within which crystallographic slipping was observed. A microprotrusion was formed on the surface of the irradiated zone, which was outwardly similar the distribution of laser radiation in the spot. The height of the microprotrusion reached 1 μm, and sometimes even more. An increase in the number of impacting impulses led to the accumulation of damage. The data obtained are in many ways similar to the acoustoplastic, electroplastic, and magnetoplastic effects. By analogy, we consider it possible to call the discovered effect optoplastic. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the composition of cluster ions in samples containing sodium stannate and tin(II) chloride. It has been shown that the composition of mass spectra is influenced by such parameters as the laser radiation energy and the substance content in the sample being studied. Conditions for preparing samples and recording mass spectra using these parameters were optimized. Presumptive identification of peaks in the recorded mass spectra was carried out. It has been shown that many of the ion peaks observed in the mass spectra may correspond to clusters containing tin. In the mass spectra of sodium stannate, ions of the general composition SnxOyNazHm were detected, in which the number of tin atoms reaches eight, and the maximum ion mass-to-charge ratio (m/z) is 1100. In the mass spectra of tin(II) chloride, there are ions of the general composition SnxOyHmClp and SnxCly, where the number of tin atoms reaches 4, and the highest m/z value is 1000. [ABSTRACT FROM AUTHOR]

The expansion and collapse of a cavitation bubble during laser heating and subcooled boiling of water in the vicinity of the tip of an optical fiber (laser heating element) installed in a water-filled glass tube with two open ends is studied experimentally and numerically. Cavitation, initiated by continuous laser radiation, is accompanied by the pushing and pulling movement of the heated liquid in the tube and outside it. For the first time, it has been shown that in a tube with an installed laser heating element in a liquid flow moving behind the walls of the bubble, when it collapses at the pole of the bubble surface remote from the end, a liquid jet appears, directed through the bubble to the end of the optical fiber. The jet speeds up the process of sucking liquid into the tube. [ABSTRACT FROM AUTHOR]

Objective(s): The waves of ultrasound and laser in the presence of nanoparticles are introduced as desirable candidates for the thermal treatment of cancer due to having fewer side effects, more speed, and superior treatment efficiency. Here, 2D Graphene oxide nanoparticle is used as a thermal nano-convertor for increasing the yield of thermal cancer therapy. Materials and Methods: The temperature of GO (in 0.2 and 0.4 mg/ml concentrations) and deionized water regarding heater, bath sonicate, probe sonicate (at a power range of 2-3.5 W), and laser properties at 808 nm with continuous wave (at a power of 0-2 W) in 10 min are investigated. Based on the experimental results, the effect of laser and ultrasound radiation on the temperature is simulated using a data mining approach. Results: Experimental and simulation results show that GO nanoparticle in this form is unsuitable for converting ultrasound waves into heat. But it is a strong absorber for electromagnetic waves at 808 nm and can raise the temperature to 85 °C. The results indicate that the laser + GO enhances the mortality percentage and treatment yield of MG63 cancerous cells by up to 85%. Also, GO uptake is analyzed by fluorescent microscopic images. Conclusion: This analysis confirmed that GO is important when laser radiation is used but not when Ultrasound is employed. Also, GO is an excellent photothermal nanoparticle for localized thermal therapy of osteosarcoma cancer cells by laser at 808 nm with low side effects. [ABSTRACT FROM AUTHOR]

Copyright of Eurasian Physical Technical Journal is the property of E.A. Buketov Karaganda University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We aim to search for axion-like particles in the eV mass range using a variable-angle stimulated resonance photon collider (SRPC) with three intense laser beams. By changing angle of incidence of the three beams, the center-of-mass-system collision energy can be varied and the eV mass range can be continuously searched for. In this paper, we present the design and construction of such a variable-angle three-beam SRPC ( t SRPC ), the verification of the variable-angle mechanism using a calibration laser, and realistic sensitivity projections for searches in the near future. [ABSTRACT FROM AUTHOR]

The interaction of laser beams with metal oxide nanoparticles can be proposed for water remediation and cancer treatment. In this paper, H2Ti3O7 nanotubes (NTs) were synthesized by anodization technique and characterized using UV–visible, Raman scattering and FTIR and spectroscopies, field emission scanning and transmission electron microscopy, zeta potential, thermal analysis, and X-ray diffraction. The results declare that monoclinic hydrogen titanium oxide with a mean crystallite size of 16.0 nm is formed. The H2Ti3O7 NTs also have an average outer diameter and shell thickness of 34.0 nm and 1.69 nm, respectively. Furthermore, the NTs have considerable thermal stability and high colloidal stability with a negative surface charge value of − 39.6 mV. Additionally, the interactions of different laser lights with H2Ti3O7 NTs in the vicinity of lung and prostate cancer as two of the first frequent malignancy worldwide in male cancer with a significant increasing trend are in vitro investigated. The effects of various concentrations of bare H2Ti3O7 NTs at different incubation times in the presence and absence of laser light are investigated to estimate the effectiveness of the photodynamic therapy. Also, different laser wavelengths, laser intensities, and exposure times are applied to treat lung (A549 cells) and prostate (LNCap cells) treatment. The results indicated that H2Ti3O7 NTs can be an excellent candidate for the treatment of lung and prostate cancers and the reasons for the success of the treatment in dark and irradiated conditions are described in the paper. [ABSTRACT FROM AUTHOR]

In this article, we report on experimental studies of the influence of several laser radiation parameters, such as the duration of the laser pulse, the radiation wavelength, and the pulse energy, on the efficiency of the destruction of urinary calculi. The study used a laser lithotripter based on a fiber Tm laser generating at a wavelength of 1940 nm with pulses with a duration of about 1800 μs and pulse energy of up to 6 J, as well as a femtosecond solid-state Yb laser generating at a wavelength of 1032 nm with a pulse duration of about 250 fs and pulse energy of up to 400 μJ. A comparative analysis was carried out according to such criteria as the productivity of lasers when removing a unit mass of images and the amount of sample displacement resulting from the retropulsion effect. The results obtained in this work demonstrated that the femtosecond laser loses approximately two times its efficiency in terms of sample material removal. However, this shows the absolute advantage of the photoionization mechanism of femtosecond laser ablation in the study of retropulsion and thermal heating, which were completely absent in this case. [ABSTRACT FROM AUTHOR]

The manufacturing and application of micro-optical elements are constantly evolving toward miniaturization, integration, and intelligence and have important applications in holographic displays, optical imaging, laser processing, information processing, and other fields. Ultrafast lasers, with their ultrashort pulse width, extremely high peak power, high processing resolution, small thermal influence zone, and nondestructive material processing advantages, have become an important processing method for preparing micro-optical elements. However, the laser output from the laser usually has a Gaussian distribution, with limitations in spatial and temporal energy and shape distribution, making it difficult to meet the requirements of processing efficiency and quality, which poses new challenges to ultrafast laser manufacturing technology. Therefore, by shaping the ultrafast laser beam and regulating nonlinear optical effects, the optimization and adjustment of the beam shape can be achieved, thus improving the quality and efficiency of micro-optical element processing. Ultrafast laser beam shaping technology provides a new method for the manufacture of micro-optical elements. This article first introduces the commonly used manufacturing methods for micro-optical elements. Second, from the perspective of the temporal domain, spatial domain, and spatiotemporal domain, the basic principles, methods, and existing problems of ultrafast laser beam shaping are summarized. Then, the application of these shaping technologies in the preparation of micro-optical elements is elaborated. Finally, the challenges and future development prospects of ultrafast laser beam shaping technology are discussed. [ABSTRACT FROM AUTHOR]

The effect of pulsed laser radiation (1064 nm, 120 s, 10 Hz, and 1.5 J/cm2) on coal samples in argon is under study. The gaseous products of coal pyrolysis is analyzed using mass spectrometry. The dependences of the composition of gaseous pyrolysis products of coal samples and the proportion of reacted samples on their technical and genetic characteristics are revealed. Data on the yield of combustible gases per unit mass of reacted coal samples are obtained. [ABSTRACT FROM AUTHOR]

This investigation of sub clover germination responses to different combinations of Laser or/and Rhizobium under laboratory conditions. To study effect of irradiation seeds by laser radiation and seeds incubation by Rhizobium combination with laser exposed times 5, 10, and 15 minutes compared in untreated seeds on the germination parameters of clover seeds. Seed germination was monitored every 8 hours for the first 4 days, then inspected every 24 hours for 15 days. Obtained results were showed that using treate seeds by combination laser exposed times and Rhizobium gave higher the germination parameters than seeds which treat by the laser exposed time. By using Laser exsed timesor/and Rhizobium, the results were indicated that the germination parameters of seed cover were decreased for seed irradiation with Laser radiation of 5, 10 and 15 minutes, respectively, compared with untreated samples (Control). While, the higher values were when using laser exposed time of 5 minutes or/hizobium, but, the lowest values were noticed when using laser exposed time of 15 minutes or/and Rhizobium, because of less than untreated seeds (Control). [ABSTRACT FROM AUTHOR]

In the present work, we used the solgel and ex situ casting techniques to synthesize a nanocomposite membrane (NCM) composed of lignosulfonate (LGS), polyvinyl alcohol (PVA), and nickel oxide (NiO) nanoparticles. Samples from the synthesized NCM were exposed to different laser fluences in the range 2–22 J/cm2. UV–vis spectroscopy and the CIE methodology were used to study the resultant effect of laser on the optical and color characteristics of the NCM. The increase of fluence up to 22 J/cm2 causes a drop in the optical bandgap (Eg) values from 5.88 to 5.56 eV when n = 1/2, associated with a rise in the refractive index. We attribute these changes to cross-linking that destroys the ordered regions and thus increases the amorphous phase. This cross-linking can lead to a more compacted structure of the LGS–PVA/NiO NCM. Additionally, the values of optical dielectric loss were calculated and plotted versus energy. The values of Eg attained from ɛ″ versus energy are nearby to those values attained by means of Tauc's relation when n = 1/2, indicating that the LGS–PVA/NiO NCM exhibited direct allowed transition. Furthermore, the CIE method was used to evaluate the color differences between the exposed NCMs and the pristine ones. We found that the value of color intensity is more than 5, suggesting permanent color changes. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Soil Sciences & Agricultural Engineering is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In many applications of joining and reinforcing timber elements with self-tapping fully threaded screws, the exact positioning of the screws becomes difficult as the screws tend to "stray" from their designated axis during insertion in wood and wooden semi-products. Experimental investigations show that besides natural local discontinuities like knots or resin inclusions, the screw-to-grain angle and the screws stiffness have an influence on the insertion process and thus can be identified as factors to a deviation of fully threaded screws. Mechanical predrilling cannot solve this problem, as the drills also stray during the predrilling process. As an alternative, a pyrolytic method of predrilling based on laser radiation proved suitable for obtaining guide holes with adequate straightness. This paper includes a description of the developed drilling processes using different lasers beam sources. The resulted borehole geometries of a QCW fiber laser, as well as an ultrashort pulsed laser, show satisfying results. Furthermore, the short- and long-term bond behavior of fully-threaded screws in a glued-laminated timber matrix, installed in laser predrilled guide holes, was tested and evaluated. The results show that with the new innovative wood processing method an exact positioning of fully-threaded screws is possible, almost without loss of withdrawal resistance of the screws. [ABSTRACT FROM AUTHOR]

Aromatic plants and laser beam wavelength in the red range of visible spectra (623.8 nm), most commonly used for treating plant species, were selected. As there is not much information in the references, it is necessary to set a scale with qualitative and partially quantitative evaluations of the results. Specimens of thyme seed (Thymus vulgaris) were selected as aromatic plants for studying the effect of low-power lasers on plant development, and continuous He-Ne laser, with irradiation times in the range of minutes. [ABSTRACT FROM AUTHOR]

Laser treatment has offered a relatively nonsurgical alternative for eye, life, and vision-sparing treatment of malignant melanoma of the choroid. Historically, the most commonly used forms of lasers were xenon-arc, argon laser, krypton laser, and the more recent transpupillary thermotherapy (TTT) and photodynamic therapy (PDT). Melanomas selected for laser treatment tend to be smaller and visibly accessible, which means these tumors are usually located in the posterior choroid. Laser treatments have been associated with both local tumor destruction and side effects. Unlike radiation therapy, laser treatment has been commonly associated with retinal traction, hemorrhage, chorioretinal neovascularization, and extra scleral tumor extension, as well as higher rates of local treatment failure. In addition, however, laser-treatment has been successfully used to treat tumor-related retinal detachments, radiation retinopathy, and neovascular glaucoma. We review the world's experience of ophthalmic laser treatment for choroidal melanoma, offer safety and efficacy guidelines, as well as a comparison of laser treatment to radiation therapy outcomes. [ABSTRACT FROM AUTHOR]

Algorithms for stochastic simulation of the signal arriving at the photodetector matrix of the aircraft navigation system are constructed. During the operation of the aircraft landing navigation system, the laser beam of the navigation system coincides in its direction with the glide path determining safe landing. Two photodetector units placed on board of the aircraft determine the glide path position in the coordinate system of the aircraft, which allows one to adjust the position of the touch point on the runway in poor visibility conditions. In this case, the estimation of the power and angular distributions of radiation recorded by the receiver of the navigation system is a relevant problem. In addition, it is interesting to study the effect of scattering of various multiplicities on the recorded signal. The algorithms developed here are based on direct statistical modelling (estimation over collisions) and local estimates of the Monte Carlo method. The calculations show that the proposed methods allow us to evaluate the efficiency of the laser navigation system in various conditions. [ABSTRACT FROM AUTHOR]

Laser technology is being widely studied for controlled energy deposition for a range of applications, including flow control, ignition, combustion, and diagnostics. The absorption and scattering of laser radiation by liquid droplets in aerosols affects propagation of the laser beam in the atmosphere, while the ignition and combustion characteristics in combustion chambers are influenced by the evaporation rate of the sprayed fuel. In this work, we present a mathematical model built on OpenFOAM for laser heating and evaporation of a single droplet in the diffusion-dominated regime taking into account absorption of the laser radiation, evaporation process, and vapor flow dynamics. The developed solver is validated against available experimental and numerical data for heating and evaporation of ethanol and water droplets. The two main regimes—continuous and pulsed laser heating—are explored. For continuous laser heating, the peak temperature is higher for larger droplets. For pulsed laser heating, when the peak irradiance is close to transition to the boiling regime, the temporal dynamics of the droplet temperature does not depend on the droplet size. With the empirical normalization of time, the dynamics of the droplet shrinkage and cooling are found to be independent of droplet sizes and peak laser intensities. [ABSTRACT FROM AUTHOR]

The leather materials are used in a multitude of sectors, including footwear, apparel, handicrafts, and the automotive industry. Due to the radiant heat generated by a laser beam, the laser cutting of leather results in a carbonized cut edge. There is currently no technology available for measuring the carbonization along the contour edges of leather. The purpose of this experimental investigation was to determine the impact of power diode-based laser cutting on the carbonization of machined buffalo leather with the help of a digital microscope to improve the machining process. The ATR-FTIR spectrum was used to analyze the carbon-related functional group in the mid-IR spectrum of carbonized leather samples. It was found that the proposed method can measure the amount of carbon deposition in the cutting zone. The lower amplitude duty cycle with higher feed rate can reduce carbon formation owing to the lower thermal energy distribution. The amplitude (4.5 V), duty cycle (70%) and feed rate (90 mm/s) can produce optimal performance measures. [ABSTRACT FROM AUTHOR]

In the present work, we used the ex situ casting technique to synthesize a nanocomposite (NC) of polyvinyl alcohol (PVA) and nanosize palladium (Pd). The Pd has a particle size in the range from 2 to 22 nm with 10 nm on average. Samples from the synthesized NC have been irradiated with different fluences ranging from 2 to 20 J/cm2 from GaAs infrared pulsed laser (5-watt power, 904 nm wavelength, 200 ns pulse duration, 1200 Hz frequency and 0.28 cm2 spot area). Nonisothermal crystallization kinetics of the synthesized NC was investigated using differential scanning calorimetry (DSC) with different cooling rates. The Jeziorny and Mo approaches were applied to describe the nonisothermal analysis. Several nonisothermal kinetic parameters, such as the crystallization peak temperature (Tc), the enthalpy of crystallization (ΔHc), the degree of crystallinity (Xc), the crystallization halftime (t1/2), the Avrami exponent (n) and the activation of crystallization (Ea) were evaluated and interpreted as a function of laser fluences. The results indicated that the incorporation Pd nanoparticles into the PVA matrix accelerate the crystallization process, while the laser radiation causes chain crosslinking that reduces the crystallinity. [ABSTRACT FROM AUTHOR]

Monochromatic hard X-rays with high brightness are desired for medical applications including Auger therapy. One can generate such X-rays through laser-Compton scattering (LCS) by allowing photons from a compact laser system to interact with electrons accelerated by a compact electron accelerator. In this paper, after a brief description of laser-Compton X-ray sources, a scheme called crab crossing to enhance the X-ray intensity is proposed. The effect of crab crossing is evaluated, and we report our dedicated laser system for the crab crossing LCS research. The luminosity enhancement factor by crab crossing is evaluated. For the electron beam, a rf deflector will be used to generate a tilted electron beam. For the laser system, chirped pulsed amplification is adopted. Yb-doped optical fibers and a Yb:YAG thin-disk is used for the laser gain media. The luminosity enhancement factor by crab crossing is expected to be 3.8 when the crossing angle is 45 degrees. 10mJ pulse energy was achieved by thin-disk regenerative amplifier. The pulse duration after the pulse compressor was about 1.5 ps. We are going to demonstrate the LCS X-ray enhancement by crab crossing of electron beam and laser pulse. The expected enhancement factor is 3.8. We have successfully finished the laser development and the proof-of-principle experiment will be conducted soon. [ABSTRACT FROM AUTHOR]

In this study, the silk fabrics mordanted at the ratio of 1%, 5%, 10%, 20% of aluminum potassium sulfate (KAl(SO4)2·12H2O) and 0.1%, 0.5%, 1%, 3%, of iron sulfate (FeSO₄) were separately dyed 50% weld (Reseda luteola L.). Then firstly, laser radiation was used on un-mordanted silk fabrics and as a second step, silk samples with different ratios mordanted and dyed with weld were irradiated to investigate the laser radiation effects on color using several combinations of the two main laser parameters namely energy density and number of pulses. Nd:YAG laser device was used two different wavelengths of 1064 nm and 532 nm, and it was found that the laser wavelength of 532 nm is most appropriate to all dyed fabrics, while 1064 nm wavelength causes damages such as discoloration and burning in the iron sulfate mordanted fabrics. Colorimetric analysis was performed to examine surface alterations of silk samples. The CIEL*a*b* color values of the silk fabrics were measured and compared with each other. In general, the use of iron sulfate (FeSO₄) as a mordant increased the color difference (ΔE*) of dyed fabrics at 1064 nm. The color coordinates and fastness values of rubbing and light were investigated. Morphological analysis was performed using optical and scanning electron microscopy. Elemental analysis was performed using SEM-EDX (scanning electron microscopy–energy-dispersive X-ray spectroscopy) to identify mordants. A reserved phase high-performance liquid chromatography (RP-HPLC) with the diode-array detection (DAD) method was utilized for the identification of the components of dyes present in the silk samples. [ABSTRACT FROM AUTHOR]

During the laser application process, laser energy is usually converted into heat energy, causing high temperature, which affects the (high-speed) aircraft in routine flight. A completely novel photochemical method was investigated to potentially minimize the energy effect of the laser beam. Ag nanoparticles/ C 3 N 4 were synthesized by an ultra-low temperature reduced deposit method with Ag mean diameters of 5–25 nm for photofixation of N 2 . The absorption performance of laser can be improved by using appropriate charge density and small size Ag metal particles. The energy absorption rate was 7.1% over Ag/ C 3 N 4 (−40) at 5 mJ / cm 2 of laser energy. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) has extremely high hardness (Mohs hardness: 9.3) and high chemical stability; thus, it is quite difficult to achieve a high material removal rate in the chemical–mechanical polishing (CMP) process. This paper presents a method to accelerate the CMP process by irradiating SiC with a femtosecond laser. The effects of laser fluence and pulse duration on the C face and Si face modification are discussed. The ablation threshold of the C face is lower than that of the Si face. After laser irradiation, the thicknesses of laser-induced periodic structures of the C face and Si face are about 1 µm due to the optical interference effect between the incident femtosecond laser beam and the surface plasmon polaritons. SiC surfaces after laser irradiation present graphitization. Moreover, the hardness of the C face of laser-irradiated SiC samples is higher than that of the Si face in the same laser fluence. In the CMP process, the material removal rates of the C face and Si face of SiC samples after laser irradiation exhibited an improvement of 77% and 207%. This study reveals the advantages of femtosecond laser in the CMP process. [ABSTRACT FROM AUTHOR]

Results of welding a wide range of light alloys by highly-concentrated heat sources have been analyzed. It is shown that the characteristic defects are hot cracks, internal pores, HAZ softening, weld sagging, undercuts and irregular reinforcement bead formation. It was found that in order to produce sound joints, it is necessary to thoroughly select welding mode parameters, remove the oxide film from billet edges before welding, ensure reliable protection of the weld pool, and in some cases and it is rational to apply preheating or concurrent heating. One of the advanced methods to minimize the susceptibility to formation of the above-mentioned defects is application of hybrid laser-arc and laser-plasma welding processes. The welds produced by electron beam and laser (СО2 - and fiber-optic lasers) welding processes are quite similar visually, by their macrostructure, as well as the main characteristics. The weld strength parameters and heat input required for full penetration of the metal are somewhat different for different welding methods (for fiberoptic laser it is usually 30 % less). 54 Ref., 3 Tabl., 8 Fig. [ABSTRACT FROM AUTHOR]

Monocrystalline AlN is a hard-brittle material. Thus, much focus has been on finding ways to treat it efficiently while minimizing damage. This work uses the molecular dynamics approach to examine the surface roughness and material removal process of monocrystalline AlN utilizing the micro-laser-aided polishing (MLA-PL) method. Hence, this study can theoretically examine the effects of temperature on the AlN material removal mechanism in the MLA-PL process using micro-laser-supported technology, using the average strength of the laser pulses as a variable. The results show that Laser irradiation in AlN affects root-mean-square roughness, subsurface damage depth, and material removal rate. Traditional polishing and MLA-PL caused dislocations, stacking defects, amorphous transitions, and hexagonal-to-cubic phase transitions. [Display omitted] • MD simulation of MLA-PL rolling-abrasive polishing of AlN is performed. • The pileup receives more heat supplied from the external laser source than from the polishing tool. • Plastic deformation of AlN happens via amorphous transition and dislocation slip motion when it is exposed to beams of laser light. • Excessive laser power density causes serious subsurface damage and higher material removal rates. [ABSTRACT FROM AUTHOR]

A dual-wavelength Q-switched Nd:YAG laser emitting at 1064 nm and 532 nm and an Er:YAG laser were tested on a range of feathers containing melanin, carotenoids and psittacofulvins. Dyed, white and iridescent feathers, as well as down feathers, were also included in the study. First, the damage threshold fluence was determined for each type of feather and then, as appropriate, laser tests were conducted on feathers artificially soiled with dust or carbon black. The Nd:YAG laser was unsuccessful at cleaning feathers soiled with carbon black. Better outcomes were obtained on feathers soiled with dust: the Nd:YAG laser was effective at both wavelengths at removing dust from white feathers, dyed feathers and yellow feathers containing psittacofulvins. Feathers containing melanin, as their main colourant, were found to have a much lower damage threshold fluence than other feathers. Also, laser radiation at 532 nm at high fluences can cause discolouration on pink feathers containing carotenoids. Finally, it was not possible to remove dust from down feathers without causing thermal damage. This investigation showed that laser cleaning using a Q-switched Nd:YAG laser can remove dust from certain types of feathers. However, further research is needed to assess any potential chemical or long-term effects of laser cleaning on feathers. Finally, the Er:YAG laser was found to be unsuitable for laser cleaning resulting in thermal damage to all feathers at low fluences. [ABSTRACT FROM AUTHOR]

Laser beam exposure rarely leads to a macular injury which may result in a serious sequelae. Here, we present the clinical features and treatment macular neovascularization confirmed by optical coherence angiography which developed following axillary laser hair removal procedure in a 29-years old pregnant woman (gestational age: 24 weeks). Following 2 consecutive intravitreal ranibizumab injection by 5-weeks interval, the visual acuity was improved from 1/10 at baseline to 8/10 at month 9. . Conclusion: Unintentional laser beam exposure related macular neovascularization can be successfully treated with the intravitreal anti VEGF agent administration. [ABSTRACT FROM AUTHOR]

Optical interference caused by gas bubbles in water is of prime concern in underwater laser micromachining process since it importantly affects the quality of laser-ablated surface and material removal rate. This study applied positive water pressure in the underwater laser ablation with the attempts to reduce the bubble size, minimize the optical disturbance to the laser beam in water, and promote the cut quality. A nanosecond pulse laser was used for grooving a single-crystalline silicon wafer in a pressurized water environment. The effects of water pressure and average laser power on groove width, groove depth, size of heat-affected zone, and cut surface morphology were examined and discussed together with the analysis of laser beam refraction in water. The results revealed that the higher the water pressure, the cleaner the cut surface, and smaller heat-affected zone and higher aspect ratio of groove were obtained. The ablation technique proposed in this paper could be a promising method for scribing silicon and plausibly other semiconductor materials at high removal rate with high cut quality and negligible damage. [ABSTRACT FROM AUTHOR]

Two types of transparent Y 2 O 3 ceramics without including large scattering sources such as residual pores, one with very high optical homogeneity (type A) and another one with slightly insufficient optical homogeneity (type B), are purposely prepared, and their optical properties are investigated and compared qualitatively and quantitatively. Type A ceramic exhibits transmittance characteristics with very low internal loss in the visible to infrared wavelength region, while type B ceramic is inferior in various optical performances especially in the short (visible) wavelength region. In type B ceramic, birefringence occurs due to optical inhomogeneity in the visible region, resulting in a decrease in the extinction ratio. Non-uniform refractive index distribution is also observed in the Schlieren image of type B ceramic, hence the laser beam quality through that material is degraded. This study proved the importance of optical homogeneity of transparent ceramics and clarified the problems in actual applications. [ABSTRACT FROM AUTHOR]

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Irradiating hohlraum targets with high-power laser pulses is a promising approach to achieve inertial confinement fusion (ICF). Unfortunately, such interaction is accompanied by intense electromagnetic pulses (EMPs). The EMPs can interfere with various physical diagnostic signals and even cause a malfunction of some crucial equipment. In this study, EMPs generated due to kJ-laser coupling with hohlraum targets are recorded using B-dot probes inside the target chamber. The configuration of the hohlraum has a more remarkable effect on EMP amplitudes compared to laser energy. 0.6 mg/cc of He gas filling in the hohlraum and the presence of the capsule inside the hohlraum both dramatically reduce EMPs. Moreover, EMP frequencies corresponding to various hohlraums are basically below 1.75 GHz. Soft X-ray (0.1–4 keV) radiant flux is used to reveal the characteristics of EMPs. The conclusions are expected to enable us to better understand the relationship of EMPs with target configuration and laser energy. [ABSTRACT FROM AUTHOR]

The laser power transfer system is one of the most promising systems in the long-range wireless power transfer field. However, the low efficiency at photovoltaic (PV) receiver limits the performance of an implemented system due to the Gaussian laser beam. Since the irradiance profile of the Gaussian laser beam is not uniform, the PV array exhibits complex output characteristics with multiple peaks, leading that the conventional maximum power point tracking (MPPT) method is not acceptable either on tracking accuracy or on tracking speed. In this article, a simple and rapid voltage-location global MPPT (VL-GMPPT) method is proposed for PV array under Gaussian laser beam condition (GLBC) in terms of reducing the voltage searching range. In order to do so, the mathematical model of PV array's global maximum power point (GMPP) is developed under GLBC. Then, the VL-GMPPT method incorporates voltage-location mechanism to directly move the operating point to the vicinity of GMPP and employs IncCond method to accurately find the GMPP. The experimental and simulation results are shown to verify the proposed GMPPT method. It was found that the proposed method can reduce 90% of tracking time that is consumed by the conventional global searching method. [ABSTRACT FROM AUTHOR]

The effect of pulsed nanosecond laser radiation (wavelength 532 nm, pulse duration 14 ns, pulse repetition frequency 6 Hz, the density of laser radiation power 0.2-0.6 J/cm2) on the tableted samples of high volatile C bituminous coal in argon medium is investigated. Among the gaseous products of pyrolysis, H2, CH4, C2H2, CO and CO2 are detected. The volume fractions of gaseous products from sample pyrolysis depending on the laser radiation power density is established. Within the laser radiation power density range 0.2-0.4 J/cm2, the volume of the formed combustible gases per unit mass of the reacted sample increases, and remains almost unchanged with further increase in power density. The volume fraction of combustible gases in the mixture of gaseous pyrolysis products are only slightly dependent on the laser radiation power density. The action of nanosecond laser radiation with a power density of more than 0.4 J/cm2 causes intense ablation of the tableted sample containing 0.005 wt.%. polyvinyl alcohol. A tableted sample containing no binding material is destroyed under the action of nanosecond laser radiation with a power density of more than 0.2 J/cm2. [ABSTRACT FROM AUTHOR]

We report, to the best of our knowledge, the first CW bismuth-doped fiber laser operating at around 1.31 μ m with an output power of > 1 W utilizing a cladding-pumping configuration with multimode semiconductor laser diodes emitting at a wavelength of 793 nm. The Bi-doped fiber (BDF) serving as an active medium of the laser was based on a pedestal-index design, where P 2 O 5 − SiO 2 glass core surrounded by P-doped cladding. The BDF construction offers advanced gain characteristics and an increased mode size (∼ 13 μ m). The fiber preform was fabricated by the conventional modified chemical vapor deposition (MCVD) method combined with all gas-phase doping technique. The BDF with low-index polymer coating provided sufficient cladding peak absorption at 750 nm belonging to bismuth active centers associated with phosphorus atoms (BACs-P) that allowed to develop a continuous-wave laser with a linear cavity configuration and enable a maximum slope efficiency of ∼ 4% with respect to the absorbed pump power. In addition, near-field spatial intensity distribution of optical beam has good quality ( M 2 < 1. 13) and close to Gaussian mode profile in x and y directions. The perspectives for optimization of BDF design and laser system configurations based on such fibers for further power scaling are discussed. • A bismuth-doped phosphosilicate glass core fiber with a P-doped pedestal design with advanced gain characteristics has been fabricated using the conventional modified chemical vapor deposition (MCVD) technique. • The first CW bismuth-doped fiber laser operating at around 1.31 μ m with an output power of > 1 W has been developed utilizing a cladding-pumping configuration with multimode semiconductor laser diodes at a wavelength of 793 nm. • A near-field spatial intensity distribution of optical beam of the laser has good quality (M 2 < 1.13) and close to Gaussian mode profile in x and y directions. [ABSTRACT FROM AUTHOR]

The capabilities of drones are increasing every day, as is the ease with which civilians can buy and fly them. Most drones are equipped with a camera that is used by a point-of-view operator and, at the same time, can be used for image capture. The use of drones creates a threat to privacy whereby anyone who can fly a drone can take pictures without permission. This study aims to create a 2-axis tracker system that can recognize a drone and locate the position of the drone camera so that a laser beam can track and dazzle the drone camera. The depth-sensing camera is used to localize the part of the target corresponding to the drone's camera and is created using the YOLOv5 algorithm as a deep-learning detector model. The drone's camera range and position are challenging to detect due to its small size. Our adaptive detection method combines drone detection and drone camera detection. The depth-sensing camera provides input in the form of a three-coordinate axis from the target. If only the drone is detected, a predictive algorithm can determine the camera's position for illumination with the laser. Alternatively, if the drone camera is detected, the laser can follow the target's movement more quickly. In this study, a green (520 nm) laser module with adjustable power is used to investigate factors that affect the dazzling range. The computer vision detection algorithm can detect and localize the position of the drone camera up to 500 cm with a confidence level of more than 65%. If the target is in the center of the field of view, the accuracy of the target position can reach 98%. The tracker can follow the drone's movement from 2 m/s to 4 m/s with a maximum error of 1.9 cm from the center point of the drone camera for close range. For long range, the maximum error is 6.2 cm. A laser power of 23.5 mW at 500 cm distance is found to be sufficient to dazzle and track drone cameras. • Drone and drone camera detection based on depth-sensing camera and YOLOv5 algorithm. • The 2-axis real-time tracking system recognizes a drone and locates the position of the drone camera. • Vision disruption based on laser dazzling. • The adaptive detection method combines drone detection and drone camera detection. [ABSTRACT FROM AUTHOR]