Vertical Irradiation Research Articles

Effect of Photoreactor Design on the Degradation of Thiamethoxam by Pure/Supported Titanium Dioxide

The environmental persistence of thiamethoxam (THX), a commonly used neonicotinoid insecticide, raises concerns about its long-term effects. This study explored the photocatalytic degradation of THX using pure and perlite supported TiO<sub>2</sub> photocatalysts in two distinct UV photoreactor configurations. Our investigation aimed to identify some optimal conditions for efficient THX removal while considering cost-effectiveness and sustainability for potential industrial applications. The results revealed that horizontal UV irradiation (System 1) significantly surpassed vertical irradiation (System 2) in both THX degradation rate and energy efficiency. This highlights the importance of photoreactor design for maximizing light utilization and mass transfer. While pure TiO<sub>2</sub> exhibited superior performance in both systems compared to perlite-supported TiO<sub>2</sub> (PST), the latter demonstrated an intriguing temperature dependence. PST achieved enhanced degradation at higher temperatures, suggesting its potential for industrial applications where waste heat is available. Furthermore, we discovered that low pH conditions substantially boosted THX degradation with PST, opening a promising avenue for optimizing industrial processes and minimizing chemical usage. This finding underscores the crucial role of operational parameters in tailoring photocatalytic performance. In conclusion, this study provided strong evidence for the effectiveness of TiO<sub>2</sub> photocatalysis in degrading THX, a persistent organic pollutant. We emphasized the impact of catalyst support, photoreactor design, and operational parameters, such as temperature and pH, on treatment efficiency. Notably, the enhanced performance of PST at higher temperatures and its responsiveness to low pH conditions suggest its potential for cost-effective and sustainable THX treatment in industrial settings. These findings pave the way for further research and development of optimized photocatalytic systems for mitigating environmental contamination by THX and other persistent organic pollutants.

Evaluation of disinfection effect of high-energy pulse ultraviolet disinfection equipment in medical institution settings

Objective: To evaluate the disinfection effect of high-energy pulse ultraviolet disinfection equipment in medical institution settings. Methods: The disinfection effect was evaluated through field tests and laboratory tests. Among them, 135 high-frequency contact points were selected from nine departments in the field test. Samples were collected before and after disinfection, and the disinfection effects of 75% alcohol wipes wiping disinfection, high-energy pulse ultraviolet disinfection robot disinfection and high-energy pulse ultraviolet handheld disinfection instrument were compared. In the laboratory test, 30 infected areas of the simulated test table were exposed to vertical ultraviolet irradiation and the bacterial-killing rate before and after disinfection was calculated. Results: In the field test, the bacteria-killing rates of 75% alcohol wipes, high-energy pulse ultraviolet disinfection robot and high-energy pulse ultraviolet handheld disinfection instrument were 94.99%, 91.53% and 95.94%, respectively, and the difference was statistically significant. The disinfection effect of the high-energy pulse ultraviolet handheld disinfection instrument was better than that of the high-energy pulse ultraviolet disinfection robot (P values <0.05). In the laboratory test, the killing log value of Staphylococcus aureus and Escherichia coli on the carrier were both greater than 3.00. In the simulated field test, the killing log value of Staphylococcus aureus on the surface samples were 4.99. Conclusion: Both the high-energy pulse ultraviolet handheld disinfection instrument and the high-energy pulse ultraviolet disinfection robot have good disinfection effects, which are similar to the disinfection effects of conventional 75% alcohol wipes.

Effect of varied amount of photocatalytically active TiO2 loaded on AlON carrier-type photocatalyst

An AlON carrier with light-transmitting performance and through-hole structure was prepared by carbothermal reduction and nitridation (CRN). The TiO2/AlON photocatalyst was prepared by hydrothermal method. Under vertical irradiation of the light source, the degradation rate of MB by TiO2(15%)/AlON photocatalyst was 97.3% after 180 min. And 88.8% MB was mineralized by determining the total organic carbon in the solution. An increase in TiO2 loading can accelerate the efficiency of TiO2/AlON degradation of MB within 0–90 min. At the same time, it will also exacerbate the blockage of AlON carrier and increase the amount of free TiO2. These can all exacerbate light loss, thereby shortening the penetration distance of light in the mixed liquid. Within the range of 90–180 min, the photocatalytic performance of TiO2(15%)/AlON powders was better than that of TiO2(25%)/AlON (97.3% vs 82.5%). In addition, TiO2/AlON photocatalyst was easy to cycle and has stable photocatalytic performance.

The effect of changing vertical irradiation angle of periapical radiography bisecting technique on the length dimension of mandibular teeth

Objectives: This research is aimed to determine the effect of changing the vertical irradiation angle with a change in angle of +10°, +5°, -5°, -10° in bisecting technique periapical radiography on the length dimension of mandibular teeth. Materials and Methods: This study used a laboratory experimental method with a post test only control group design. The samples used in this study were teeth I1, I2, C, P1, P2, M1, and M2 region 4. All teeth were treated by changing the angle from the standard angle recommended by White and Pharoah with changes of +10°, +5°, -5°, and -10° in each tooth using a Morita Veraview iX 70 Kv, 7mA dental X-ray unit. Results: The results showed that the angle change of -10°, -5° causes foreshortening and +10°, +5° causes elongation. Based on the results of the Saphiro-Wilk and Kruskal-Wallis test, it is known that there are significant differences in the dimensions of tooth length at +10°, +5°, -5°, -10° against changes in the angle 0° or angulation form White and Pharoah (p &lt; 0.05) . Conclusion: There is a significant effect on the change of vertical irradiation angle with angle changes of +10°, +5°, -5°, -10° in bisecting technique periapical radiography on the length dimension of mandibular teeth.

An experimental study on the effect of CO2 laser powers on melting characteristics of clear ice – Part II: Vertical irradiation

Icing phenomenon widely exists and plays negative effects in aviation and electricity fields. Laser deicing technology is a typical non-contact and high-efficiency deicing method. To accurately predict and control the laser-induced ice melting process, an experimental study on melting characteristics of clear ice under vertical CO2-laser irradiation and natural convection is carried out, with the laser power varied at a range of 20–60 W. As resulted, the axial melting rate tends to increase and then decrease with the increase of laser power. The maximum of average and instantaneous axial melting rate at 40 W are 5.85 mm/s and 13.95 mm/s, respectively. The higher the laser power, the larger the peaks of maximum melting length. At 20 W and 60 W, the peaks of maximum melting length are 10.51 mm and 12.19 mm, respectively. There is little correlation between the deflection of angle and laser power. At 30 W and 50 W, the maximum angles of melting length are 0.77° and 2.52°, respectively. When the melting depth is smaller than 81.5 mm, the maximum energy efficiency at 20 W is 64.8 %, while when it is greater than 81.5 mm, the maximum energy efficiency at 60 W is 63.6 %. Results of this study are meaningful for the optimization of laser deicing technology.

Field-effect transistor and giant magnetoresistance effect based on optically induced antichiral edge state in graphene

We propose a peculiar method to induce the antichiral edge state (AES) based on off-resonant circularly polarized (ORCP) light and further study its edge-state transitions and transport properties in zigzag graphene nanoribbon. The results show that the vertical irradiation of the ORCP light on two boundaries of the system could be regarded as a modified Haldane model for inducing the AES. In particular, under the antiferromagnetic (AFM) exchange field, the system with the AES can be controlled by an electric field between spin-polarized (SP) AESs and band insulators. As a result, a SPAES/AES/SPAES junction can be formed. In two SPAES regions, the spin orientation of the SPAES can be modulated by an electric field, giving rise to the switch between the on state with enhanced conductance contributed by two edge channels and a bulk channel, and the off state. Furthermore, by modulating the AFM exchange field in two SPAES regions as parallel and antiparallel configurations, the corresponding conductance is significantly different due to the different spin directions of the AES, finally leading to giant magnetoresistance effect that can be cut off and tuned on by an electric field. In addition, the transport properties based on the AESs are moderately robust against the disorder. These findings provide a view to study the peculiar AESs and are expected to be applied in electronic devices based on the AESs.

Assessing the co-heating test as reference for heat loss coefficient estimation: In-depth analysis on an artificial dataset

In order to bridge the building energy performance gap it is necessary to quantitatively and qualitatively characterize the actual energy demand of buildings and the thermal behaviour of their envelopes. Current European legislation prescribes the assessment of the energy efficiency of the building stock by means of energy performance certification, which labels the building performance based on theoretical data and specifications reflecting the design phase. At the current state, in most European countries such certificates provide the only insight into the overall performance of the building stock, while the need of characterizing the actually achieved building behaviour is recognized. The most common testing procedure used with the aim of characterizing the as-built thermal performance of commissioned dwellings is the co-heating test. It consists of a prescribed measurement procedure where a vacated house is submitted to an elevated indoor temperature. During the experiment, the indoor and outdoor environment, as well as the energy demand needed to maintain the stable indoor temperature are precisely monitored. Up to date, this testing procedure is acknowledged as the most reliable in practice, however, the limitations of the methodology are not yet completely explored and unambiguously defined. Thus, the aim of this work is to explore the limits of the co-heating testing procedure on artificially generated experiments which provide a completely defined environment and reference targets. To assess the impact of different aspects, such as the parameters of the statistical models or monitoring period and length, the artificial datasets provide the ideal conditions since the impact of measurement inaccuracy can be avoided and the expectations of the methodology itself can be evaluated. The main findings complement the prevalent research and indicate the possibility of assessing the building performance in the 10% bounds from the target, however considering idealised monitoring data. The research shows that using global horizontal instead of south vertical irradiation can provide overall more accurate results, especially in transient months. Finally, when assessing suitable periods for performing tests in a moderate climate, only 20% of the whole year can be considered to yield satisfactory results.

An experimental study on the effect of CO2 laser powers on melting characteristics of ice with trapped air bubbles under vertical irradiation

Icing occurs frequently and plays negative effects in natural and industrial fields. Air bubbles are always trapped in the ice during freezing, and then affect the thermal and mechanical properties of ice. As a typical non-contact and high-efficiency deicing method, laser deicing technology is tested on melting ice with trapped air bubbles, under vertical CO2 laser irradiation and natural convection, with the laser power varied at a range of 20 ∼ 60 W. As resulted, the axial melting rate tends to increase and then decrease with increasing laser power. The maximum values of average and instantaneous axial melting rate at 40 W are 5.46 mm/s and 12.32 mm/s, respectively. At 40 ∼ 60 W, the higher the laser power, the larger the average melting length after stabilization. At 40 W and 60 W, the average melting length are 3.60 mm and 5.59 mm, respectively. It is found little correlation between the melting angle and laser power. At 30 W and 50 W, the maximum melting angles in the front view are 2.49° and 1.15°, respectively. During the whole melting process, the highest energy efficiency is maintained at 20 W, and the maximum energy efficiency is 69.1%. Results of this study could provide a reference for the application of laser deicing technology.

Low-volume-loss surface polishing with a krypton fluoride excimer laser for polycrystalline diamond films

Surface polishing of hard diamond coatings is a key technique for applying such coatings in industry. In this study, we demonstrated surface modification of polycrystalline diamond films with minimal volume loss of the films by vertical irradiation of KrF excimer laser beams. Optimized laser scanning selectively removed surface asperities and reduced the surface roughness from ∼0.1 to ∼0.05 μm. Raman spectroscopic measurements revealed that laser polishing involves the phase transformation of diamond to amorphous carbon phases and thermal oxidation or evaporation of the amorphous phases. The residual amorphous carbon was almost completely removed by subsequent laser irradiation at appropriate fluences. We consider that the surface texture inherent to polycrystalline diamond films plays an important role in the concentration of laser beams on the nearby film surface. From reciprocating slide-type friction tests, we found that laser polishing decreased the initial friction coefficient from 0.5 to 0.1–0.3 against alumina balls and reduced the abrasion of the mating materials.

Theoptical‐thermalmodeling of carbon black filled glass fiber reinforced poly‐ether‐ether‐ketone in laser assisted tape winding

AbstractTo facilitate the application of carbon black filled glass fiber reinforced poly‐ether‐ether‐ketone (CB‐GF/PEEK) prepreg in laser assisted tape winding (LATW), a finite element method is used to analyze the optical‐thermal characteristics of the following three prepregs with distinct laser absorption properties: (i) 0.5%CB (incomplete absorption), (ii) 2.74%CB (complete, single‐layer absorption), (iii) 4%CB (complete, near‐surface absorption). Thus, the energy distribution, temperature distribution and thermal accumulation are revealed, and the heating strategy is customized according to the laser absorption characteristics of each prerpeg. Then the feasibility of CB filled GF/PEEK prepreg in LATW is verified by manufacturing and testing NOL rings. Finally, the nip‐point irradiation scheme is optimized. The simulation results reveal a significant difference between the optical‐thermal characteristics of the 0.5%CB and those of the other two prerpegs. Benefited from the energy leakage, the 0.5%CB facilitated twice melting by thermal accumulation, along with a higher nip‐point temperature. Meanwhile, the mechanical performance tests of the NOL rings indicate a similar tensile strength of ~1300 MPa for the 0.5%CB and 4%CB, while the interlaminar strength of the 0.5%CB is slightly higher than that of the 4%CB. The latter result may be due to the higher nip‐point temperature of the 0.5%CB, which promotes resin diffusion and enhances the bonding strength. Finally, an optimized heating strategy with short laser length, vertical irradiation of the nip‐point is proposed, and is shown to reduce the ineffective thermal accumulation and ensured the suitability of Tape and Laminate temperature.

Floating Carbon Nitride Composites for Practical Solar Reforming of Pre-Treated Wastes to Hydrogen Gas.

Solar reforming (SR) is a promising green-energy technology that can use sunlight to mitigate biomass and plastic waste while producing hydrogen gas at ambient pressure and temperature. However, practical challenges, including photocatalyst lifetime, recyclability, and low production rates in turbid waste suspensions, limit SR's industrial potential. By immobilizing SR catalyst materials (carbon nitride/platinum; CNx |Pt and carbon nitride/nickel phosphide; CNx |Ni2 P) on hollow glass microspheres (HGM), which act as floating supports enabling practical composite recycling, such limitations can be overcome. Substrates derived from plastic and biomass, including poly(ethylene terephthalate) (PET) and cellulose, are reformed by floating SR composites, which are reused for up to ten consecutive cycles under realistic, vertical simulated solar irradiation (AM1.5G), reaching activities of 1333 ± 240 µmolH2 m-2 h-1 on pre-treated PET. Floating SR composites are also advantageous in realistic waste where turbidity prevents light absorption by non-floating catalyst powders, achieving 338.1 ± 1.1µmolH2 m-2 h-1 using floating CNx versus non-detectable H2 production with non-floating CNx and a pre-treated PET bottle as substrate. Low Pt loadings (0.033 ± 0.0013% m/m) demonstrate consistent performance and recyclability, allowing efficient use of precious metals for SR hydrogen production from waste substrates at large areal scale (217 cm2 ), taking an important step toward practical SR implementation.

Ultrasmall Fe2O3 Tubular Nanomotors: The First Example of Swarming Photocatalytic Nanomotors Operating in High-Electrolyte Media.

Self-propelled chemical micro/nanomotors (MNMs) have demonstrated considerable potential in targeted drug delivery, (bio)sensing, and environmental remediation due to their autonomous nature and possible intelligent self-targeting behaviors (e.g., chemotaxis and phototaxis). However, these MNMs are commonly limited by their primary propulsion mechanisms of self-electrophoresis and electrolyte self-diffusiophoresis, making them prone to quenching in high electrolyte environments. Thus, the swarming behaviors of chemical MNMs in high-electrolyte media remain underexplored, despite their potential to enable the execution of complex tasks in high-electrolyte biological media or natural waters. In this study, we develop ultrasmall tubular nanomotors that exhibit ion-tolerant propulsions and collective behaviors. Upon vertical upward UV irradiation, the ultrasmall Fe2O3 tubular nanomotors (Fe2O3 TNMs) demonstrate positive superdiffusive photogravitaxis and can further self-organize into nanoclusters near the substrate in a reversible manner. After self-organization, the Fe2O3 TNMs exhibit a pronounced emergent behavior, allowing them to switch from random superdiffusions to ballistic motions near the substrate. Even at a high electrolyte concentration (Ce), the ultrasmall Fe2O3 TNMs retain a relatively thick electrical double layer (EDL) compared to their size, and the electroosmotic slip flow in their EDL is strong enough to propel them and induce phoretic interactions among them. As a result, the nanomotors can rapidly concentrate near the substrate and then gather into motile nanoclusters in high-electrolyte environments. This work opens a gate for designing swarming ion-tolerant chemical nanomotors and may expedite their applications in biomedicine and environmental remediation.

Photoelectric current generation in a monolayer MoSe2–WS2 lateral heterojunction

Based on density functional theory calculations and non-equilibrium Green’s function method, we study the photovoltaic effect of monolayer MoSe2–WS2 lateral heterojunction under vertical irradiation. Combined with the differential charge density, it predicts the stability of the MoSe2–WS2 heterojunction and the high possibility of charge transfer from MoSe2 to WS2. As a result, such MoSe2–WS2 lateral heterojunction breaks the spatial inversion symmetry thus leading to a photocurrent. The resultant photocurrent increases from close to zero to a maximum value in the range of photon energy of 1.7 eV–2.8 eV. The photocurrent response fits the cosine function with respect to the polarization angle. The peak photocurrent is obtained when the photon energy is 2.8 eV, and can be attributable to the large density state peaks near −1.3 eV in the valence band and 1.5 eV in the conduction band. Meanwhile, the single-layer MoSe2–WS2 lateral heterojunction exhibits higher polarization sensitivity that is characterized by an extinction ratio of up to 9.6. These results suggest possible applications of the single-layer MoSe2–WS2 lateral heterojunction in next generation optoelectronic devices.

Bulk Physical Properties of a Magnetic Weyl Semimetal Candidate NdAlGe Grown by a Laser Floating-Zone Method

In this study, we report the successful growth of single crystals of a magnetic Weyl semimetal candidate NdAlGe with the space group I41md. The crystals were grown using a floating-zone technique, which used five laser diodes, with a total power of 2 kW, as the heat source. To ensure that the molten zone was stably formed during the growth, we employed a bell-shaped distribution profile of the vertical irradiation intensity. After the nominal powder, crushed from an arc-melted ingot, was shaped under hydrostatic pressure, we sintered the feed and seed rods in an Ar atmosphere under ultra-low oxygen partial pressure (&lt;10−26 atm) generated by an oxygen pump made of yttria-stabilized zirconia heated at 873 K. Single crystals of NdAlGe were successfully grown to a length of 50 mm. The grown crystals showed magnetic order in bulk at 13.5 K. The fundamental physical properties were characterized by magnetic susceptibility, magnetization, specific heat, thermal expansion, and electrical resistivity measurements. This study demonstrates that the magnetic order induces anisotropic magnetoelasticity, magneto-entropy, and charge transport in NdAlGe.

Bio-inspired micro/nanomotor with visible light dependent in situ rotation and phototaxis

In nature, many microorganisms (such as volvox) normally rotate in situ and exhibit the phototactic motion when they sense the changes of the light signal. However, it is still challenging for the artificial micro/nanomotor counterpart to achieve such switchable motion behavior. Herein, we report a biomimetic visible light driven micro/nanomotor (MNM) with motion behavior similar to that of the volvox. The MNM, which consists of Ag nanoparticle decorated WO3 microrod (with a size of ∼5 μm), exhibits the in-situ rotation with an angular speed of ∼ 4.67 rad/s (under vertical light irradiation with an intensity of 600 mW/cm2) and shows the negative phototaxis when the irradiation condition is changed to the tilted one (e.g. 45° incident angle) with the angular and linear velocities of ∼ 4.59 rad/s and ∼ 1.47 μm/s, respectively. The biomimetic motion behavior relies on the interaction between the two underlying mechanisms, i.e. self-electrophoresis and self-diffusiophoresis. More interestingly, the MNM exhibits the controlled in situ clockwise/counterclockwise rotation with designated angles (e.g. 90°, 180°). The results in the current study may further boost the development of light-driven MNMs with biomimetic features for a wide range of microfluidics, microrobotics, and cargo transportation applications.

COMPUTATIONAL STUDY OF RADIATION CHARACTERISTICS IN THE NICHE OF THE EXPERIMENTAL DEVICES OF THE WWR-K REACTOR

A nuclear reactor is a complex engineering and technical installation that generates radiation. Because of this, the experimental measurement of the radiation characteristics of a nuclear reactor is a difficult task, and in some cases technically impossible. The modern development of calculation codes and tools makes it possible to determine the radiation characteristics of a nuclear reactor with sufficient accuracy and reliability. Due to this, computational modeling of physical processes occurring in a nuclear reactor has become one of the main scientific research methods. The WWRK reactor is a multi-purpose research reactor with a large number of vertical and horizontal irradiation positions used for a wide range of scientific and applied problems. The irradiation position with the largest dimensions in the WWR-K reactor is the niche of experimental devices, which makes it possible to irradiate objects up to 1000 mm in diameter. This position is considered as a candidate for neutron transmutation doping of silicon ingots with a diameter of more than 200 mm. The article presents the radiation characteristics for the current and modernized configuration of the niche of the experimental devices of the WWR-K reactor. It is shown that the upgrade of the configuration leads to an improvement in the neutron characteristics in the irradiated position.

SEU Tolerance Efficiency of Multiple Layout-Hardened 28 nm DICE D Flip-Flops

Three layout-hardened Dual Interlocked Storage Cell (DICE) D Flip-Flops (DFFs) were designed and manufactured based on an advanced 28 nm planar technology. The systematic vertical and tilt heavy ion irradiations demonstrated that the DICE structure contributes to radiation tolerance. However, it is hard to achieve immunity from a Single Event Upset (SEU), even when a ~3-µm well isolation is utilized. The SEU mitigation of the hardened DFFs was affected by the data patterns and clock signals due to the imbalance in the number of upset nodes. When the clock signal equalled 0, no error was observed in 181Ta irradiation, indicating that the DICE DFFs are SEU tolerant in vertical irradiation owing to their reasonable isolation of sensitive volumes. The divergences of SEU cross-sections were enlarged by our specially designed joint change of tilt incidences for both the along-cell and cross-cell irradiation of heavy ions. The evaluations of SEU for both the vertical and tilt irradiations assist with eliminating the overestimation of SEU tolerance and guarantee the in-orbit safety of spacecraft in harsh radiation environments.

Predictive modeling of microhole profile drilled using a focused electron beam with backing materials

This study establishes a simple and rapid predictive model for a microhole profile drilled using a focused electron beam based on the finite difference method. Vertical irradiation and full penetration using a focused beam with a Gaussian distribution were reflected onto the three-dimensional mesh of metallic substrates. The predictive hole profiles on the substrate were estimated by analyzing the phase transition using predictive temperature distributions. To validate the predictive accuracy of model, experimental drilling processes on AISI 304 stainless steel substrates were conducted, and the experimental hole qualities were measured using microcomputed tomography. Comparisons between predictive and experimental results represented high predictive accuracy in three criteria: hole diameters, straightness, and geometrical hole shape. Applying the fractional energy absorptance dependent on the substrate depth significantly improved the prediction accuracy of model. The predictive results demonstrated that the thermal analysis with temperature distributions could predict the drilled hole qualities rapidly and accurately, avoiding the high computational loads from considerations for velocity fields or pressure distributions around the substrate.

Thermographic diagnostics of instability of endoprostheses of large joints with assessment of somatosympathetic vasomotor reflex

Forty two patients with total hip (12 patients) and total knee (30 patients) replacements were examined by computer thermography method. Total joint replacement was performed after bone tumor resection. It was shown that additional afferent impulsation occured at implant loosening and the degree of vertical polysegmental irradiation of sympathic neurons excitation as well as the deficit of spinal cord inhibition on the side of arthroplasty incresed. Thermographic evaluation of the amplitute and volume of somatosympathic vasomotor reflex is an effective for the diagnosis of joint prosthesis loosening and it is subsidiary to the radiologic control.

Energy Performances of Tensile Material in Building Renovation in the Nordic Region

Tensile materials are increasingly used in the building envelope as second-skin systems, despite a lack of investigation on their effects. In this work, a second-skin system integrating a tensile material as an outer layer has been adopted in the retrofit analysis of two of the most common building typologies in the Norwegian context. The simulations were carried out by implementing a custom control logic for the system, considering the outdoor air temperature and the global vertical irradiation on the façades. The proposed retrofit solution allowed for a primary energy saving of about 35%.