Additional Supply Research Articles

Solar Wireless Electric Vehicle Charging System

This project outlines the design and implementation of a solar-powered electric vehicle charging station that addresses the dual challenges of high gasoline prices and harmful emissions. The number of countries adopting electric vehicles continues to rise, as they not only promote environmental sustainability but also significantly lower transportation costs by substituting expensive fuels with more affordable electricity. In this context, developing an electric vehicle charging infrastructure offers an innovative and effective solution. This system enables electric vehicles to charge while in motion, eliminating the need for stationary charging stops. Powered entirely by solar energy, it requires no additional power supply. The system incorporates solar panels, batteries, transformers, regulator circuits, copper coils, AC/DC converters, Atmega328P controllers, and LCD displays. This technology demonstrates the feasibility of an on-road solar-powered wireless charging system for electric vehicles.

Sustainable additive manufacturing supply chains with a plithogenic stakeholder analysis: Waste reduction through digital transformation

The Additive Manufacturing (AM) industry is of paramount importance as means of personalized design capabilities by rapid prototyping, using exact amount of required materials avoiding waste, and applying Industry 4.0 technologies with digital transformation ability. The characteristics of AM are regarded as the prerequisites for sustainability in the manufacturing industry. However, there are limited papers discussing the stakeholders and sustainability objectives in a single comprehensive analysis. Hence, the purpose of this research is to identify the degree of each stakeholder to achieve the objective of sustainability in AM supply chain by proposing a novel Plithogenic Fuzzy MACTOR approach. Results reveal that the customers are in triggering position to shape entire AM supply chain as the demand generators. Workforce is a significant player in the AM supply chain by creating the design, manufacturing, marketing, and communicating to provide the collaborations in this business segment. Academia positions here a supportive role to enable the whole supply chain members in terms of delivering technological advancements, training people, and providing the workforce. The AM manufacturers and material / software / printer suppliers are the key players leading to the supply chain by producing the main business products. Thus, a practitioner can interpret its position in the AM supply chain and understand the requirements of sustainability points in detail. Besides, this study provides a theoretical contribution to the literature by extending the MACTOR analysis with Plithogenic sets via including a different uncertainty measure.

Specific features of production and use of transportation biofuels in selected developing countries (part II)

Aim. To identify specific features of production and use of transportation biofuels in selected developing countries, as well as to assess the potential of bioethanol industry development in the Russian Federation (RF).Objectives. To assess the economic efficiency of bioethanol production in Russia; to reveal the potential of applying foreign experience in the development of bioethanol industry in our country.Methods. In the process of the research the methods of system analysis, comparative analysis, method of expert evaluations, mathematical, statistical methods were applied.Results. The actual estimation of economic efficiency of bioethanol production in Russia was obtained. The cost of a unit of bioethanol, which is equivalent to a liter of gasoline in terms of energy content, is 5-36% higher than the cost of a liter of gasoline (depending on the production technology). At the same time, state support for the production and use of bioethanol in our country is reasonable. This will allow to create additional demand for grain crops and reduce carbon dioxide emissions from motor transport. The production and use of bioethanol will form an additional supply in the gasoline market, will give an opportunity to support projects on deep processing of grain and wood chemistry.Conclusions. The experience of Brazil, China and Indonesia in the development of bioethanol industry is relevant for Russia. At the same time, in order to minimize possible risks in the field of food security at the initial stage of bioethanol industry development, low-quality grain stocks should be used as feedstock and the production of second-generation bioethanol should be stimulated.

Effects of feed particle size, calcium concentration and phytase supplementation on InsP6 degradation in broiler chickens fed pelleted diets

ABSTRACT 1. The objective of the trial was to study the single and interactive effects of feed particle size in pelleted feed, dietary calcium (Ca) concentration and microbial phytase supplementation in broiler chickens. The studied traits were myo-inositol (1,2,3,4,5,6) hexakis (dihydrogen phosphate) (InsP6) degradation, pre-caecal digestibility of phosphorus (P), Ca and amino acids (AA) and retention of P, Ca and nitrogen (N). 2. Male Ross 308 broiler chickens were housed in metabolism units in groups of 10 and allocated to one of eight diets with seven pen replicates per diet. The 2 × 2 × 2-factorial arrangement included coarse and fine feed particle size (309 or 222 µm), low and high Ca concentration (4.9 and 7.2 g/kg) and without or with phytase supplementation (1,000 FTU/kg). 3. Pre-caecal InsP6 disappearance was higher with coarse than fine feed particle size when no phytase was added (54 vs. 48%) but not when phytase was added (74%; p = 0.046). High dietary Ca feeds decreased pre-caecal InsP6 disappearance (67 to 59%) and P digestibility (65 to 55%; p < 0.001). Gizzard pH was lower with coarse than fine feed particle size and higher with high Ca than low Ca (p < 0.001). Pre-caecal digestibility of most AA was approximately 3.5%-points lower with high Ca without phytase compared to the other treatments (p ≤ 0.047). Coarse feed particle size caused higher pre-caecal AA digestibility than fine particle size (~2%-points; p ≤ 0.031). InsP6 disappearance in the crop increased at high Ca concentration when phytase was added (22 vs. 37%; p = 0.011). 4. Coarser feed particle size in pellets increased gastrointestinal InsP6 degradation and nutrient digestibility, likely owing to effects on the gizzard functions. Additional Ca supply exerted antinutritive effects that was not compensated for by using coarser feed particles.

What is the True Cost of Motion Preservation? A Time-driven Activity-Based Cost Analysis of Anterior Cervical Discectomy and Fusion Versus Disc Replacement

Total disc replacement (TDR) has become a viable alternative to anterior cervical discectomy and fusion (ACDF) for select patients. Although most comparative studies have assessed outcomes, cost differences remain largely uninvestigated. This information is critical as we move towards value-based reimbursement. To address this knowledge gap, we used time-driven activity-based costing (TDABC) to compare total intraoperative costs between the two procedures. Total cost was divided into direct (personnel and supply cost) and indirect costs (administrative and overhead costs). Individual costs were determined through direct observation, electronic medical records, and through querying multiple departments (including business operations, sterile processing, plant operations, and pharmacy). Timestamps for all involved personnel and material resources were documented, in conjunction with process mapping of the intraoperative period. Total intraoperative costs were estimated for all ACDFs (n=810) and TDRs (n=54) from 2017 to 2022. Regression analyses were performed to identify factors associated with total cost. A total of 810 and 54 patients underwent one- and two-level ACDFs and TDRs, respectively. The average total intraoperative cost for an ACDF was $6,776 +/- $2,808, compared to $12,026 +/- $4,235 for TDR. Supply cost accounted for the majority of total cost for both procedures ($4,173 +/- $2,225 for ACDF and $9,532 +/- $4,010 for TDR). On multivariable linear regression analysis, TDR was associated with roughly $3,885 of additional cost compared to ACDF (p<0.001), as well as $4,072 in additional supply cost (p<0.001), most of which was driven by the higher cost of implants (p<0.001). TDABC is a highly useful methodology for estimating differences in true costs between procedures and determining cost drivers. TDRs were associated with an additional $3,885 of total intraoperative cost as compared to ACDFs, the majority of which was driven by the cost of implants.

Detached Plasma Studies in GOL-NB with Extra Gas Injection

The magnetic system of an open trap usually includes expansion sections located between highfield magnetic mirrors and end surfaces that receive plasma. In the GOL-NB device, an arc plasma gun is located in one of the expanders, which creates a low-temperature starting plasma in the confinement area. The parameters of the surface plasma sheath affect the electrical connection of the confinement area with the walls and, thereby, affect the contribution of the line-tying effect to the plasma stability and the longitudinal energy losses from the trap. The experiments with additional hydrogen injection into the plasma gun were carried out at GOL-NB. We observed a radiating plasma formation detached from the surface, which visually corresponds to that in radiating divertors in tokamaks. In both standard and detached modes, decaying plasma existed near the receiving electrodes during the entire observation time after the discharge current was terminated. In the central trap of GOL-NB, some structures in the Fourier spectrogram of magnetic fluctuations manifest earlier in the detachment mode than in the standard mode and have lower frequencies. We associate these structures with the onset of interchange-like modes due to the loss of plasma stabilization by the line-tying to the conducting ends. The observed plasma response to the additional gas supply confirmed our understanding of the line-tying effect as the main factor stabilizing the plasma core in the initial phase of density accumulation in the central trap.

Implementation of a Standardized Process of Coude Catheter Insertion Decreases Traumatic Catheterizations

ObjectiveTo address the issue of traumatic foley catheterization we developed and implemented a coude catheter education program for operating room nurses as well as standardize the usage of a coude catheter for male patients. Traumatic catheterization leads to patient morbidity and increased healthcare costs. MethodsA retrospective review was conducted to identify all traumatic catherizations over a 6-month period for several surgical services at our institution. A nursing education program was implemented that included basic urological anatomy, coude urethral catheter insertion techniques, and catheter safety. We conducted our trial over a period of 2-months with all catheterizations tracked. Following the trial, the process and outcomes were reviewed and then implemented for all male patients >18 years old requiring indwelling catheter placement in the operating room. ResultsOn retrospective review there were 18 traumatic foley catheterizations of patients on the three surgical services out of a total 601 catheter placements (3% traumatic placement rate). The total cost of these traumatic catherizations was $27,793 when accounting for additional procedures, supplies, and additional OR time required for each traumatic catheterization. The average cost per patient was $1,544. After full implementation of the process across all operating room services in June 2021 there have been 2038 catheterizations performed using a coude catheter kit with 4 traumatic foley placements through May 2022 (0.2% traumatic catheterization rate). ConclusionImplementation of the nursing education program and utilization of the coude catheter for all male catheterizations reduces costs, decreases iatrogenic urethral injury, and improves patient safety.

A passive self-excited oscillation AC low-voltage energy harvesting circuit without a bridge

Most current electromagnetic energy harvesters use capacitor voltage multipliers or boost circuits controlled by external signals to step up and store energy. However, for most low-voltage output electromagnetic energy harvesters, generating switching control signals and rectification results in significant energy loss. To reduce these losses, this paper proposes an AC boost circuit without additional power supply or rectifier bridge, designed for low-voltage electromagnetic energy harvesting. Both theoretical analysis and experimental results confirm the effectiveness of the proposed interface. The results show that the circuit can start self-excited boosting at an initial voltage of 0.48V and achieve an AC-DC conversion efficiency of 71.3 % within an input voltage range of 0–2.9V.

Urban trees left high and dry – Modelling urban trees´ water supply and evapotranspiration under drought

Abstract Long-lasting extreme weather conditions are expected to occur more frequently in the future owing to climate change, as demonstrated by the recent heat waves. In particular, the decrease in precipitation during the summer months had a significant impact on urban tree water availability. Therefore, it is imperative to develop methodologies for determining the available water supply and evaporation rates for urban trees. We mapped data from 49 urban small-leaved linden trees with varying characteristics including groundwater levels, shading situations, tree pit sizes, pavement materials, and sealing ratios. By combining these data with an adapted Penman-Monteith method to calculate evapotranspiration, we simulated the soil water storage and evapotranspiration rates of these trees during the very dry year of 2018 as an example. Model validations were performed using lysimeter and sap-flow studies on Tilia cordata trees in 2022.&amp;#xD;During the growing season, most trees experienced water stress on &gt; 85% of the days because of weak precipitation events that failed to refill soil water storage. In contrast, trees with additional water supply through capillary rise reached water stress approximately 45 d later. The model results suggest that many trees will require additional water supply during predicted droughts in the future, which could have significant implications for urban forestry management. This model approach can be used to test and refine future water supply management strategies, making it a useful planning tool for improving the water efficiency of trees in urban areas and blue-green infrastructure.&amp;#xD;

Solar-Hydrogen system of additional power supply and digital control system for on-board power supply system

Even for short space flights, such as manned flights to the Moon back in the 60s, it became extremely obvious that electric batteries are completely unsuitable because of their huge mass needed to store the required supply of onboard energy. Therefore, already in the 60s of the last century, the USA and the USSR took the path of using a hydrogen storage system using hydrogen fuel cells.Solar-hydrogen energy systems for spacecraft reliably provide energy for carrying out various kinds of unscheduled work on board and for eliminating emergency situations. Surplus energy is constantly accumulated on board in the form of the chemical energy of cryogenic hydrogen. The article presents too the result of the development of a solar-hydrogen power supply system for spacecraft, the onboard network of which provides slow and fast processes. This paper delves into designing digital control systems for power conditioning devices on the example of charging-discharging device based on a boost DC-DC converter. The device was implemented to condition a storage battery by properly charging and discharging it. A technique for constructing a small signal model of the converter has been developed. This involves constructing a block diagram using the discontinuous switching functions and analog models of electrical circuit components. The transfer functions of the analog controllers for the two-loop subordinate control system were derived. Then the procedure of a bilinear z-transform to the given transfer functions was applied. As a result, the discrete transfer functions of the digital controllers were obtained. Realization both analog and digital controllers in Matlab Simulink confirmed their identical behavior and stability within the power converter. Experimental studies of the static and dynamic waveforms of the digital control system showed controllability and stability of the charging-discharging device for the storage battery in typical operating modes. Thus, the method of synthesizing digital control systems for energy converters is proved valid and applicable for designing new power conditioning devices within modern power supplies.

Divide and Save: A Critical Care Air Transport Team Case With Prolonged Field Care

ABSTRACT Critical care air transport teams (CCATTs) specialize in providing intensive medical and postoperative resuscitative care during air evacuations. In a 2014 mission, a seasoned CCATT was urgently deployed to evacuate 6 American service members with gunshot wounds. Despite only having 2 hours of premission preparation and no further injury or treatment details, CCATT secured additional equipment, medications, and blood supply. Upon arrival to a foreign nonmilitary hospital, they discovered that American ground commanders had lost trust in local medical capabilities. One patient experienced prolonged extremity tourniquet time and surgical delay. This led to acute renal failure, preventing immediate evacuation without continuous renal replacement therapy (CRRT). Deviating from the standard procedure, the CCATT obtained permission to split their team. The CCATT nurse attended 5 stabilized patients during unregulated critical care air transport with plans to swiftly return with CRRT equipment for the critical sixth patient. The physician and respiratory therapist remained at the foreign hospital for 2 days to provide prolonged field care. This case demonstrates the evolving mission scope of CCATT, which may encompass ground triage, prolonged field care, unregulated movement, and atypical CCATT equipment such as CRRT, occasionally necessitating a split team construct. To adapt to these evolving needs, updated policies and training now incorporate these diverse CCATT concepts, emphasizing the importance of flexibility in en route critical care missions.

A novel 4-point scleral fixation technique with a hydrophobic IOL: The LOTO technique.

to describe a new surgical technique that combines 4-point, flanged polypropylene scleral fixation with a hydrophobic IOL. Using the Envista MX60 and 6.0 polypropylene, scleral 4-point fixation was achieved using a flanged-suture technique 5 times in a model eye and in a case series of 8 patients, retrospectively reviewed. The polypropylene is passed through each eyelet in a novel configuration (LOTO: Loop to Optic and Trailing ends to Outside). Conjunctival peritomies, scleral flaps/pockets, glue, and suture knots are avoided. The load needed for haptic fracture and scanning electron microscopy (SEM) at fracture sites were studied. Haptic fracture occurred once following the first model eye implantation due to excessive suture tension. The fracture load was similar between the LOTO and the simple-pass technique (1.08 ± 0.52 N vs 1.09 ± 0.32 N), suggesting no safety compromise. SEM did not disclose cheese-wiring effect. Over a mean follow-up of 10.8 months (range: 3 to 19; median 11.5 months), all cases experienced visual improvement with best-achieved-postoperative uncorrected visual acuity (BAPUCVA) of 20/25-20/200, and the IOL was well-centered. Postoperative IOL tilt averaged 2.9 degrees (range: 0 to 9.6; median: 2.9 degrees). Two patients developed post-operative CME treated topically. The first case developed flange extrusion that was readily repaired in clinic. This novel technique adds 2 main advantages to previously described flanged-suture techniques: 1) 4-point fixation of a hydrophobic IOL and 2) immediate application at the time of initial complicated cataract surgery since it requires no additional supply, IOL, or instrumentation.

De novo Cu-MOF@CNS nanocomposite coated on a cotton fibrils framework for sustainable solar-driven desalination.

Environmental researchers are extremely concerned about addressing the declining availability of drinking water, which is a critical issue in many nations. Solar-driven desalination is an emerging and pioneering renewable approach to reduce potable water scarcity that is suitable for remote locations, developing countries, and disaster zones as it does not require additional energy supply. However, there are still issues with the scalable preparation of photothermal materials, such as achieving low cost and widening the assortment of useful applications. Conventional carbon- and metal-based absorbers are intricate and fragile, which make them difficult to install and transport in places with minimal infrastructure. Thus, a universal process for creating adaptable solar evaporators is sorely required. Herein, we have come up with a holistic approach using a solar absorber (GJ-01(Cal)) derived from a Cu-MOF (HKUST-1) and carbon nanosheets (CNSs) for generating potable water from saline water using solar radiation. The as-synthesized material provides high-performance photothermal water evaporation when illuminated under solar irradiation at the air-water interface. Moreover, its porous structure, high photothermal conversion efficiency, rapid water flow, and heat insulation make it appropriate for saline water desalination. CNS play a pivotal role in improving the photothermal features of the solar absorber (GJ-01(Cal)) in terms of conjugation to promote Cu(0) species and pyrrolic nitrogen (P-N) amplification and thereby enrich the p-type nature of the absorber's triphasic configuration. With these photothermal factors, the localised surface plasmon resonance (LSPR) of electrons increases and achieves high solar spectrum absorption. The GJ-01(Cal) was further coated on porous cotton fibrils (CF) that regulate photothermal interfacial evaporation (PTIE) by allowing water transportation via capillary action. This assemblage of the nanocomposite on CF efficiently evaporates water at a higher surface temperature of ∼47 °C under one solar illumination, achieving 4.23 kg m-2 h-1 of evaporation flux and 96.5% light-to-heat conversion efficiency. Interestingly, the GJ-01(Cal) coated over CF can be recycled at least 10 times. Additionally, it offers scalable production for higher photothermal efficiency with a flexible substrate as a solar evaporator and is beneficial for society paving new horizons towards a sustainable environment.

A two-stage stochastic programming framework for blood product inventory management with ABO substitution and lateral transshipment

This work proposes a two-stage stochastic optimization model for managing the inventory of a two-echelon blood supply chain comprised of a blood center and a network of hospitals and transfusion points. The proposed model identifies optimal distribution quantities across the supply chain, considering demand stochasticity and product perishability. Furthermore, the model utilizes redistribution policies, such as lateral transshipment and product substitution based on ABO compatibility, as corrective actions to minimize outdates (i.e., expired product) and shortages across the network. Using a computational experiment that includes a network with one regional blood center and twenty hospitals, we show that inventory management policies that include both ABO substitution and transshipment can significantly decrease the expected total network costs. Similarly, we see corresponding reductions in the expected number of outdated units and emergency requests to external networks for additional supply to satisfy unmet demand.

Winter entrainment drives the mixed layer supply of manganese in the Southern Ocean

AbstractDespite the subnanomolar dissolved manganese concentrations that can co‐limit Southern Ocean primary production, their physical supply mechanisms during winter, for biological consumption in spring and summer have not yet been explored. During austral winter and spring 2019, two cruises were conducted in the Atlantic sector of the Southern Ocean, to determine the distribution and surface water supply mechanisms of dissolved manganese in the upper water column. The supply mechanisms were used to calculate the total flux of dissolved manganese to productive surface waters and were compared to biological consumption estimates. Mean dissolved manganese concentrations in the upper water column (&lt; 500 m) during winter and spring were comparably low (≤ 0.34 nmol kg−1; p &gt; 0.05), with seasonal mixed layer reservoir sizes averaging 65.21 ± 12.93 and 21.64 ± 19.32 μmol m−2, respectively. Winter entrainment contributed 89.33–99.99% (average 97.26% ± 5.28%) of the total dissolved manganese flux, while diapycnal diffusion contributed 0.52–10.58% (average 4.92% ± 5.14%), was identified as the dominant mechanisms for transporting dissolved manganese into the mixed layer in the subantarctic zone, polar frontal zone, and antarctic zone. Here, the winter physical supply rates were higher than the estimated consumption rates during spring, meeting phytoplankton biological demands. Whereas in the subtropical zone, the supply rates were lower than the consumption rates, indicating the presence of additional supply mechanisms such as coastal upwelling, which may help to meet the biological demands in this region.

Self-powered system for real-time wireless monitoring and early warning of UAV motor vibration based on triboelectric nanogenerator

Unmanned aerial vehicle (UAV) is widely used in various industries due to their high flexibility and large maneuverable space. Abnormal vibration of UAV motors can prevent it from working properly due to the abnormal state of the motors and the harsh external environment. There is no suitable method to monitor the UAV motors vibration in real time. At the same time, commercial sensors require an additional power supply to power the sensor, which indirectly limited their application in UAVs. A vibration sensor (AV-TENG) with magnetic spring structure was proposed in this paper for monitoring the vibration of UAV motors. The experimental results show that the magnetic spring has excellent stability. AV-TENG can achieve frequency detection in a wide frequency band. It also has excellent linearity with a maximum error of only 0.0062 %. Simultaneously, to verify the performance of AV-TENG in various environments and simulate its loading, the results demonstrate that AV-TENG can adapt well to the working conditions of UAV. Finally, this paper constructs a low-cost (less than $7), easy-to-manufacture signal acquisition system, and conducts a field demonstration, realizing the monitoring of the vibration frequency and acceleration of the UAV motors, and realizing the early warning, which is expected to promote the development of the field of UAV as well as the practical application of the triboelectric nanogenerator.

Application of flow-through flaps for replantation after traumatic limb amputation according to the angiosome concept.

This study was performed to explore the treatment of the injury caused by traumatic limb amputation. From October 2002 to October 2021, 30 cases were enrolled in the present study. The reasons for injury were as follows: 8 cases with single hydraulic column crush injury, 12 cases with gear and wire rope stranding, 6 cases with belt avulsion injury, and 4 cases with carbon block smash injury. The present study application of a free or small saphenous vein bypass to reconstruct the injured artery and vein according to the concept of the angiosome model. The defective vessels were bridged with the axial vessels of a flow-through flap, such as a medial calf flap or anterolateral femoral flap, to construct an additional blood supply and drainage vein for the severed limb. The clinical data of 30 cases with traumatic limb amputation of the lower leg and ankle were retrospectively analyzed. In all 30 cases of traumatic limb amputation, the replantation via the adoption of a flow-through flap was successful, and 85.6% of the patients remained in good postoperative condition. There were no symptoms of ischemia in the marginal segment after blood supply reconstruction of the transected limb by axial vascular bridging within the flap. Via the adoption of microsurgical techniques, the blood supply to the transected limb can be reconstructed by bridging the defective vessels with the adoption of the axial vessels of the flow-through flap is a feasible and advanced treatment option.

Biotechnological and economic assessment of the productivity of Chlorella vulgaris IBSS-19 microalgae under different cultivation regimes

The production of microalgae biomass and the management of productivity plays an important role in global biotechnology. This research aimed to study the kinetic characteristics of C. vulgaris growth, conduct an economic analysis of biomass production, and develop a simple optimization model for choosing the optimal cultivation regime. The results showed that the additional CO2 supply increased the specific growth rate of C. vulgaris by 35 % and increased productivity by 47 %. Analysis of the batch growth curve of microalgae revealed potentially effective cultivation cycles, which were two, four, and six days. Economic analysis revealed that the greatest biomass yield can be obtained using a two-day cultivation period. Depending on the biomass yield, the cost of production, net income, and profitability of production were calculated according to the cultivation cycles.

АНАЛИЗ НАДЕЖНОСТИ СРЕДСТВ ИНДИВИДУАЛЬНОЙ ЗАЩИТЫ ОРГАНОВ ДЫХАНИЯ ПОЖАРНЫХ

The article examines the analysis of the equipment of fire and rescue units of the Ministry of Emergency Situations of Russia in the Vladimir region with personal respiratory and visual protection equipment for firefighters. The statistics of their failures are presented, as well as the process of determining the most unreliable elements of the personal respiratory and visual protection equipment for firefighters, as well as an analysis of the causes of failures. It was determined that the main reasons for the failures of the personal respiratory and visual protection equipment for firefighters are a decrease in the reliability of the functional elements of the pulmonary automaton: a violation of the tightness of the housing, incomplete switching on/off of the additional air supply button (bypass) due to mechanical action on the actuator (springs, membranes), a change in the shape and chemical composition of plastic elements. It is shown that a significant number of negative factors affect the reliability of the personal respiratory and visual protection equipment for firefighters. The results of the study will be useful for both responding fire and rescue units and manufacturers of personal respiratory and visual protection equipment for firefighters in terms of forecasting and monitoring the reliability of their elements. In practice, this will increase the safety and efficiency of fire protection units in an inhospitable environment.

Self-powered intelligent liquid crystal attenuator for metasurface real-time modulating

Triboelectric Nanogenerator (TENG) is capable of efficiently capturing mechanical energy and transforming it into electrical energy for self-powered systems, making it an ideal power source for Polymer Dispersed Liquid Crystal (PDLC). Herein, a Self-powered Intelligent Liquid Crystal Attenuator (SPILCA) is demonstrated for metasurface real-time modulating. The convergent beam-shaping metasurface consisting of holey meta-atoms with diameters ranging from 100 nm to 300 nm is fabricated by e-beam lithography (EBL). While the unique optical characteristics of the metasurface can be modulated within a certain frequency range, the E7 Liquid Crystal (E7-LC) has a large index of birefringence, and it can be powered by TENG to switch between two optical response states. Therefore, the combination of metasurface and SPILCA can achieve real-time control of metasurface by using the electricity regulatory of LC and the electromagnetic response of the metasurface. In order to build this SPILCA for metasurface modulating, a vertically contact-separated TENG based on Nylon electrospun film as triboelectric material is proposed. The maximum values of the open-circuit voltage, short-circuit current, transferred charge are 165 V, 25 µA, and 86 nC, respectively. By measuring the optical power and testing the modulation effect of SPILCA on the metasurface, it can be seen that the SPILCA has a good modulation effect on the optical signal, and even can reach 96 % intensity modulation when the laser source wavelength is 450 nm and the current is 0.09 A. This self-powered photoelectric response device does not require additional electrical power supply, and has great potential in future smart optical system design.