Efficient Micro Research Articles

Биологически активные гидролизаты белков молока и их комплексы включения с циклодектринами

Enzymatic hydrolysis of dairy proteins increases their nutritional and biological value while reducing their allergenic potential. The subsequent complexation of peptides with cyclodextrins (CDs) reduces the bitterness of the hydrolyzed proteins. The research objective was to obtain hydrolysates of whey proteins and their cyclodextrin inclusion complexes with peptides, as well as to describe the peptide composition of the cleaved dairy proteins, biological activity, and sensory profile of the hydrolysates and inclusion complexes. The research featured enzymatic whey protein hydrolysates with an extensive hydrolysis degree and their inclusion complexes with β- and γ-CDs. Dairy proteins were hydrolyzed with alcalase, and the hydrolysates obtained were subjected to micro- and ultrafiltration (cut-off limit – 10 kDa). The peptide composition of the hydrolyzed proteins was determined by the methods of high-performance liquid chromatography and chromatography-mass spectrometry. The antimutagenic activity was evaluated using the Ames test whereas the antibacterial effect was studied with the impedimetric method. The antioxidant activity was detected with fluorimetry and spectrophotometry. The method of competitive enzyme immunoassay was applied to reveal the antigenic properties. The bitterness of the experimental sample s was determined by a sensory evaluation. The research delivered the optimal modes for whey protein cleavage with alcalase that made it possible to achieve efficient micro- and ultrafiltration. The resulting hypoallergenic peptide fractions and their inclusion complexes with β- and γ-CDs possessed antioxidant, antibacterial, and antimutagenic properties. The whey proteolysis and subsequent filtration with/without tindalization demonstrated a 265/589-fold decrease in the residual antigenicity. The fluorimetric method showed a 1.79/1.90-fold increase in the antioxidant activity of the hydrolysate in complexes with β- and γ-CDs. Binding of β-CDs to peptides enhanced their antimicrobial activity against Escherichia coli ATCC 8739 and Staphylococcus aureus ATCC 6538. The hydrolysate samples with β-CDs showed less bitterness. Whey proteolysis with alcalase under optimized conditions and subsequent fractionation resulted in a product with high consumer qualities. Enzymatic hydrolysates of dairy proteins and their CD inclusion complexes were able to substitute native protein components. Their bioactive properties, good taste, and low allergenic potential mean good prospects for the functional food industry.

Nanoporous carbon derived ZIF-67@MWCNTs-Fe3O4 reinforced hollow fiber to performe hollow fiber solid-phase micro extraction (HF-SPME) coupled with high-performance liquid chromatography to determine deltamethrin and cypermethrin

This study presents a novel micro extraction approach by developing a highly porous and stable Co@N-C/MWCNTs sorbent capable to addresses limitations of traditional sorbents. Zeolitic Imidazolate Framework-67 (ZIF-67) interconnected with magnetic Multi-walled Carbon Nanotubes (MWCNTs) selected as the template for the synthesis of sorbent possess distinctive N-doped and metal (Co) active sites coupled with carbon-rich nanotubes, resulting in a sorbent with a strong affinity to target analytes and excellent chemical stability. For the first time, this material integrated into the pores of a hollow fiber (HF) for a simplified and efficient Hollow Fiber Solid Phase Micro extraction (HF-SPME) method. This innovative integration increases the extraction surface area and minimize matrix interference. Under optimal conditions, the method achieved a wide linear range (0.1–200 μg L−1) for the target analytes, deltamethrin (DLT) and cypermethrin (CPM), the coefficient of determination of 0.9945 for DLT and 0.9982 for CPM. Additionally, it demonstrated excellent analytical performance with: Low limits of detection (LODs): 0.03 µg L−1 for DLT and 0.04 µg L−1 for CPM. Good precision: Inter and intra-day relative standard deviations (RSD) within 2.5–3.4 %. High enrichment factors (EFs): 68–58. The novel Co@N-C/MWCNTs coating, integrated with a hollow fiber, offers a promising advancement for HF-SPME due to its unique properties.

Research on the aerodynamic characteristics of dragonfly leading edge.

Dragonflies are some of the most stable and maneuverable flying organisms. To explore the mechanism of how dragonfly leading edges enhance flight lift, this article conducts a detailed study on the leading edge veins and the microstructures on them of dragonfly wings. Observations have discovered the special leading edge vein and the regularly distributed microstructures on the leading edge vein. A biomimetic model has been established, and computational fluid dynamics (CFD) simulation analysis has been conducted on the biomimetic model. The analysis explores the effects of microstructure characteristics, distribution patterns, and positions on the aerodynamic characteristics of dragonfly gliding. The analysis shows that the leading edge structure influences the incoming flow, simultaneously promotes the formation of the leading edge vortex (LEV), and increases the lift-to-drag ratio by up to 4%. A wing prototype featuring biomimetic microstructures is subsequently fabricated and tested in wind tunnel experiments. Compared with a control group without leading edge structures, the airflow passing through the biomimetic structures is influenced by the shape and arrangement of these structures. The smoother transition of the leading edge vein's shape facilitates the flow of air. The microstructures primarily filter and accelerate the airflow. The spacing of the microstructures affects the stability of the airflow, thereby influencing aerodynamic performance. Additionally, the middle-row arrangement of microstructures is more beneficial for gliding conditions, while the upper-row arrangement is more advantageous for flapping conditions. These findings enhance our understanding of insect wings and advance micro aerial vehicle applications. RESEARCH HIGHLIGHTS: This study observed the leading-edge veins and microstructures of dragonfly wings in detail. Using a biomimetic model and computational fluid dynamics (CFD) simulations, it was found that these leading-edge structures promote the formation of leading-edge vortices (LEV), increasing the lift-to-drag ratio by up to 4%. Wind tunnel experiments demonstrated that wings with biomimetic microstructures significantly improved airflow smoothness and lift compared with control wings. Additionally, the arrangement of microstructures greatly affects airflow stability and aerodynamic performance, with middle-row arrangements being more beneficial for gliding and upper-row arrangements for flapping conditions. These findings enhance our understanding of insect wings and provide innovative guidance for designing efficient micro aerial vehicles.

Thermodynamic analysis of MHD Prandtl-Eyring fluid flow through a microchannel: A spectral quasi-linearization approach

In designing efficient micro devices, particularly microchannels used in cooling electronic components and biomedical microfluidic systems, The foremost application explored is the design and optimization of microchannels employed in the electronic device cooling systems. To possess these microchannels from overheating and damaging their gentle electronic components, exact fluid flow and heat transmission regulation are required. To better design cooling systems, engineers can use mathematical models of Prandtl-Eyring fluid flows to antedate temperature and velocity profiles. The entropy generation also helps in optimizing the design for better fluid transport efficiency. Therefore, the present aim is to characterize the impact of dissipative heat along with magnetization in Prandtl-Eyring non-Newtonian fluid via microchannel. The novelty of the study is the assumption of convective thermal boundary conditions that show efficient heat transport phenomena. A set of similarity rules is adopted for the transformation of the governing equations, and a spectral quasi-linearization technique is then utilized for the solution of the designed miniature. One of the special attractions of the proposed study is the analysis of entropy, which is obtained due to the irreversibility processes within the system. However, irreversibility occurs because of heat transfer, diffusion processes, viscous dissipation, etc. The physical behavior of the pertinent factors is deployed graphically, whereas the validation of the result in a particular case is displayed in tabular form. We use a second law analysis to determine the origins of irreversibility in the thermal system. It is evident that an increase in fluid parameters results in a reduction in entropy generation. An augmentation in the Biot number substantially intensifies the Bejan number. The findings suggest that the magnetic parameter and fluid parameter α have a diminishing effect on velocity.

Efficient standalone micro thermoelectric generator powered by low noise premixed combustion

The distributed backup power source is vitally important under emergency conditions. Micro combustion powered thermoelectric generator (μ-CPTEG) is a promising candidate as a distributed backup power source. This study innovatively designed an all-in-one configuration to develop an efficient, standalone, and silent μ-CPTEG. The newly proposed all-in-one configuration organically integrates air-preheating, fuel premixing, low-noise combustion, efficient heat collection, and smooth heat compensation and spreading. Such an all-in-one configuration creates a standalone μ-CPTEG with an overall efficiency greater than 4.2 %, which is much larger than those in previous standalone μ-CPTEGs. The present μ-CPTEG incorporates 8 TE modules, and generates an electric power of 53.2 W with a running sound pressure level of 48 dB. Such performance indicates that the average electric power per TE module reaches 6.65 W, corresponding to a TE potential release level of 80.7 % systematically. The overall efficiency, as well as the efficiency of heat recovery, combustion, heat collection, TE and combined heat and power, are explored in detail. Comprehensive discussions are conducted to uncover the dense fog of releasing the TE potential at a systematic level in an μ-CPTEG. The present study provides a concrete method to develop a powerful, standalone, and silent μ-CPTEG.

Efficient continuous synthesis of long-chain alkylbenzenes catalyzed by ionic liquids in microreaction systems

Alkylbenzene (LAB) is an important benzene derivative that can be used as a raw material for high-performance anionic surfactants such as alkylbenzene sulfonates (LAS) to meet the new requirements for surfactants in many fields. LAB can be synthesized through Friedel-Crafts reaction in the presence of acidic catalysts as alkylating agents, which is commonly used in the production of fine chemicals. In this work, a novel and efficient continuous flow micro reaction system was introduced to enhance the production of long-chain alkylbenzene catalyzed by [(CH3)3NH][Al2Cl7] ionic liquid. The optimal conditions were investigated for the synthesis of long-chain alkylbenzenes with the 1-tetradecene and mixing α-alkenes of C14-C16 from Fischer-Tropsch process. The results showed that the yield of benzene alkylation can achieve 99 % under the optimal process conditions which the reaction tube length was 2000 mm, the reaction temperature was 30 ℃, the catalyst dosage was 0.30 mL/min and the molar ratio of aluminum chloride to trimethylamine hydrochloride was 2:1. In addition, α-alkenes with C14-C16 lead to deactivation of the ionic liquids catalyst easier because of transfer of AlCl3 from the ionic liquid to the organic phase compared to the pure 1-tetradecene as an alkylating agent. Continuous synthesis of the long-chain alkylbenzenes catalyzed by ionic liquids can achieve in the microchannel reaction system by controlling the flow patterns.

Effect of scandium concentration on the performances of cantilever based AlN unimorph piezoelectric energy harvester with silicon nitride substrate

Microelectromechanical systems (MEMS) offer its ability to sense, control and actuate on sub-micron scale and exhibit its effect on macro scale. To implement any specific MEMS system, small, efficient and long-lifespan micro power sources are required. Piezoelectric energy harvester (PEH) along with radioactive source is one of the most promising approaches to harness electrical energy at micro to millimeter range. In this report, a scandium (Sc) doped Aluminium Nitride (AlN) unimorph piezoelectric energy harvester has been demonstrated. Unimorph piezoelectric layer is built on Silicon Nitride (Si3N4) substrate platform that act as cantilever beam and that can be vibrated by inbuilt radioactive system. In particular, Si3N4 as cantilever material and the impact of Sc doping concentration on electrical and mechanical properties of AlN piezoelectric thin film materials have been studied in MATLAB simulation platform. Results obtained from numerical study suggests that the proposed energy harvester model composed of AlScN unimorph piezoelectric (with 10% Sc doping concentration, Sc-10%) layer and Si3N4 cantilever can yield a maximum power output of ~ 19.33 μW and overall mechanical energy conversion efficiency of ~ 91.07%. These are the maximum output power and mechanical energy conversion efficiency numerically obtained from Sc doped AlN piezoelectric energy harvester systems to the best of our knowledge.

Optimization of the Offshore Wind Turbines Layout Using Cuckoo Search Algorithm

Wind turbines have gained popularity as one of the efficient micro grid energy generation sources over the years. However, wind energy yield has been greatly impacted by the wind farm wake effect, especially when the size of the wind farm becomes very large. One way to address this challenge is through wind turbine arrangements and their scalability. Developing effective means of optimizing wind farm configurations is a major concern for energy communities. This has continuously led to increased power generation and a corresponding cost reduction. As such, this research article developed an optimal large-scale offshore wind turbine placement based on wind farm layout design. The system developed focuses on wind turbine placement in wind farm layouts that have a negative influence on the capital investment due to the increasing wake effect thereby reducing energy production. A multi-objective function consisting of wake effect and component costs within the wind farm is formulated. After-which a cuckoo search algorithm technique is employed in the wind farm model to optimize the optimization problem (minimizing the wake effect while improving power output and cost). Four test case scenarios were considered when implementing the wind model. The results obtained from the developed scheme were compared with those obtained when other optimization techniques were used, using power output and cost as performance metrics. The obtained power output and cost for the test case scenario in the ideal wind turbine position on the wind farm are 18288.3KW, 19680.1KW, 18879.9KW, 21105.8KW and 26.9, 28.7, 26.9, and 29.8KW, respectively. This shows that the result obtained from the developed scheme outperformed that obtained from PSO and that of WOA.

Retraction: Study of thermal characteristics of energy efficient micro channel heat sinks in advanced geometry structures and configurations: a review

Retraction: Study of thermal characteristics of energy efficient micro channel heat sinks in advanced geometry structures and configurations: a review

Extraordinary thermal conductivity for carbon nanotube encapsulated linear carbon chain

Carbyne is a sp1 linear carbon chain (LCC) with characteristics of strong chemical reactivity and extreme instability under environmental conditions, which has become an obstacle to the application of LCC with high thermal and electrical conductivity. Utilizing CNT as a container to store LCC is one of the most feasible ways to realize LCC applications. However, current research of LCC encapsulated in CNT (LCC@CNT) focuses on its preparation and lacks of in-depth exploration of the intrinsic heat transfer mechanism. This paper reports the high axis thermal conductivity of LCC@CNT, explore the thermal transport enhancement degree of LCC@CNT under a wide temperature range and multiple diameters, and analyzed the underling mechanism through crucial thermal parameters and phonon theory. When LCC is loaded in CNT, the axial thermal conductivity of CNT is further increased by 15 %. Moreover, LCC@CNT shows the lower sensitivity diameter than pristine CNT. This work is expected to provide data support for the application of LCC, the lower production standard of CNT, and also attempt the higher efficient one-dimensional thermal energy transfer micro devices.

Influences of hybrid fiber-reinforcement using wollastonite and cellulose nanofibers on strength and microstructure characterization of ultra-high-performance mortar

This paper presents the effect of incorporating wollastonite microfibers and cellulose nanofibers on mechanical properties and microstructure of ultra-high-performance mortar (UHPM). Cellulose nanofibers of 0.005%, 0.015%, and 0.030% are combined with 4.8% wollastonite microfiber by weight of binder, which consists of 10% silica fume and 90% cement. Compressive and flexural strengths of the UHPM specimens are measured at 7 days. The microstructure is characterized in terms of SEM/EDX, XRD, FTIR, and nanoindentation. The results show the effectiveness of the fiber hybridization in enhancing the compressive and flexural strength of ultra-high-performance mortar with the improvement in flexural toughness and fracture energy by as much as 10% than control mortar. Moreover, hybrid fiber-reinforcement based on the microstructural analysis provided more synergic effect and uniform distribution of the fibers, thus developing an efficient micro crack bridging mechanism as well as resulting in enhanced toughening properties and an increased load carrying capacity. Additionally, the combination of wollastonite microfibers and cellulose nanofibers promoted the hydration reaction products and contributed a denser matrix between the fibers and cement matrix, resulting in an increase of the microstructure and interface area between the fibers and cement matrix. Nano indentation analysis also confirmed the increase of UHD C-S-H from 65% to 84% and lower percentage of anhydrous phase in ultra-high-performance matrix after combining wollastonite microfibers and cellulose nanofibers.

Sustainable Soil Additives for Water and Micronutrient Supply: Swelling and Chelating Properties of Polyaspartic Acid Hydrogels Utilizing Newly Developed Crosslinkers.

Drought and water shortage are serious problems in many arid and semi-arid regions. This problem is getting worse and even continues in temperate climatic regions due to climate change. To address this problem, the use of biodegradable hydrogels is increasingly important for the application as water-retaining additives in soil. Furthermore, efficient (micro-)nutrient supply can be provided by the use of tailored hydrogels. Biodegradable polyaspartic acid (PASP) hydrogels with different available (1,6-hexamethylene diamine (HMD) and L-lysine (LYS)) and newly developed crosslinkers based on diesters of glycine (GLY) and (di-)ethylene glycol (DEG and EG, respectively) were synthesized and characterized using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) and regarding their swelling properties (kinetic, absorbency under load (AUL)) as well as biodegradability of PASP hydrogel. Copper (II) and zinc (II), respectively, were loaded as micronutrients in two different approaches: in situ with crosslinking and subsequent loading of prepared hydrogels. The results showed successful syntheses of di-glycine-ester-based crosslinkers. Hydrogels with good water-absorbing properties were formed. Moreover, the developed crosslinking agents in combination with the specific reaction conditions resulted in higher water absorbency with increased crosslinker content used in synthesis (10% vs. 20%). The prepared hydrogels are candidates for water-storing soil additives due to the biodegradability of PASP, which is shown in an exemple. The incorporation of Cu(II) and Zn(II) ions can provide these micronutrients for plant growth.

Organic laser power converter for efficient wireless micro power transfer

Wireless power transfer with collimated power transmission and efficient conversion provides an alternative charging mode for off-grid and portable micro-power electronics. However, charging micro-power electronics with low photon flux can be challenging for current laser power converters. Here we show laser power converters with organic photovoltaic cells with good performance for application in laser wireless power transfer. The laser selection strategy is established and the upper limit of efficiency is proposed. The organic laser power converters exhibit a 36.2% efficiency at a 660 nm laser with a photon flux of 9.5 mW cm−2 and achieve wireless micro power transfer with an output of 0.5 W on a 2 meter scale. This work shows the good performance of organic photovoltaic cells in constructing organic laser power converters and provides a potential solution for the wireless power transfer of micro-power electronics.

Electrospun fiber-based micro- and nano-system for delivery of high concentrated quercetin to cancer cells

The anticancer potential of quercetin (Q), a plant-derived flavonoid, and underlining molecular mechanisms are widely documented in cellular models in vitro. However, biomedical applications of Q are limited due to its low bioavailability and hydrophilicity. In the present study, the electrospinning approach was used to obtain polylactide (PLA) and PLA and polyethylene oxide (PEO)-based micro- and nanofibers containing Q, namely PLA/Q and PLA/PEO/Q, respectively, in a form of non-woven fabrics. The structure and physico-chemical properties of Q-loaded fibers were characterized by scanning electron and atomic force microscopy (SEM and AFM), X-ray powder diffraction (XRD), differential scanning calorimetry (DSC), goniometry and FTIR and Raman spectroscopy. The anticancer action of PLA/Q and PLA/PEO/Q was revealed using two types of cancer and nine cell lines, namely osteosarcoma (MG-63, U-2 OS, SaOS-2 cells) and breast cancer (SK-BR-3, MCF-7, MDA-MB-231, MDA-MB-468, Hs 578T, and BT-20 cells). The anticancer activity of Q-loaded fibers was more pronounced than the action of free Q. PLA/Q and PLA/PEO/Q promoted cell cycle arrest, oxidative stress and apoptotic cell death that was not overcome by heat shock protein (HSP)-mediated adaptive response. PLA/Q and PLA/PEO/Q were biocompatible and safe, as judged by in vitro testing using normal fibroblasts. We postulate that PLA/Q and PLA/PEO/Q with Q releasing activity can be considered as a novel and more efficient micro- and nano-system to deliver Q and eliminate phenotypically different cancer cells.

Water and Food Sustainability in the Riparian Countries of Lake Chad in Africa

Lake Chad is a strategic water resource shared by more than 40 million people in Sub-Saharan Africa. In the 1960s, it served as a primary source of water for irrigation and fishing in the region, but the capacity of Lake Chad to supply water for irrigation plummeted by 90% at the beginning of the twenty-first century. With some initiatives taken by the neighboring countries, Lake Chad has recovered about 5% of its water volume in recent years. This research conducted an extensive literature review on Lake Chad and its riparian countries. The four major riparian countries were given particular attention due to their significant stake in the sustainability of lake Chad. This review identified and analyzed the water usage trends in this region, both before and after the lake’s decline in water levels. Our research findings revealed that riparian countries around Lake Chad have experienced an 80% increase in population growth and that the lake has now been reduced to 10% of its original size in the 1960s. Animal production in the region has increased significantly, too, particularly in Chad, and this increase of over 75% has contributed to the conflicts between farmers and herders in the region. The possible solutions proposed for the restoration of Lake Chad include increased water harvesting activities in the basin, developing a legal framework for sustainable water use, incentive-based policies for stakeholders to mitigate climate extremes events, establishing a joint water administration for the basin, and introducing regenerative agricultural practices with a highly efficient micro irrigation system.

A high temporal-spatial resolution three-dimensional imaging method using arrayed-focus structured illumination with differential axial enhancement

High precision and fast three-dimensional (3D) microscopic imaging technology plays an extremely important role in MEMS, micro optics, microelectronics, biomedicine and other fields. In this paper, a confocal microscopic 3D imaging method based on differential array focusing structured light illumination (DAF-SIM) is proposed. Theoretical analysis and experimental results show that under the 100x/NA 0.95 objective lens, the lateral resolution of this method reaches 173 nm, exceeding the optical diffraction limit, the axial sensitivity is better than 10 nm, and the time resolution is about 3 Hz@2.3 M Pixel, achieving the goal of high horizontal and axial resolution and time resolution. The high spatial and temporal resolution of DAF-SIM 3D micro imaging method provides a highly applicable, efficient and high-precision online micro terrain detection scheme for intelligent manufacturing and other fields.

A novel and efficient dual-antenna micro plasma thruster

A novel dual-antenna micro plasma thruster (DMPT) driven by radio-frequency (rf) power supply is proposed and characterized experimentally. The Langmuir probe (LP) and the retarding potential analyzer (RPA) are applied to measure the plasma parameters. The results show that compared to the single-antenna, the dual-antenna yields higher electron density, electron temperature, and ion energy. The measurements from the rf I–V probe indicate that the power coupling efficiency for the dual-antenna is about 2.6 times higher than that for the single-antenna. The plasma potential drop in the plume of the DMPT is the reason for the formation of ion beam. The neutral gas temperature is measured by rovibrational ban matching of the first negative band system of ionic nitrogen (N2+) for operating powers of 20 W up to 100 W. The total thrust of the DMPT has been calculated by the sum of the ion thrust and the neutral gas thrust. The total thrust at 100 sccm argon flow rate and 100 W rf power is ∼2.23 mN, which indicates an up to 168% thrust gain compared to the cold gas thrust, and a significant 11% total thrust is attributed to the ions’ electrostatic acceleration. The specific impulse and thruster efficiency at the above experimental conditions are ∼76 s and ∼0.8%, respectively. These initial results show that the dual-antenna scheme has better performance and is more promising than the traditional single-antenna design for electrodeless micro-electric propulsion. This novel and efficient micro plasma thruster is particularly useful for cubic satellites and scientific experiments in space (such as gravitational wave detection) which require gesture and orbit control of great precision.

Experimental investigation of the effects of the Reynolds number on the performance and near wake of a wind turbine

Wind tunnel experiments provide worthwhile insights for designing efficient micro wind energy harvesters and large-scale wind turbines. As wind tunnel tests with large-scale wind turbines are expensive and not always feasible, most experiments are conducted with geometrically scaled rotors. Furthermore, micro-scale runners used for wind energy harvesting face the issue of lower efficiency than large turbines. A better understanding of Reynolds number effects induced by the downsizing of a turbine would help to design more efficient wind energy harvesters and more faithfully scaled experiments. This paper reports on Reynolds number effects on the performance and wake of micro-scale wind turbines. Wind turbines’ power and torque coefficients are measured in a wind tunnel for a wide range of Reynolds numbers. The wake axial velocity fields and the vortex core locations are collected for three Reynolds numbers using phase-averaged and phase-locked particle image velocimetry technique. The results emphasize that an increase in the Reynolds number leads to larger power coefficients, torque coefficients, and optimum tip-speed ratios. Higher Reynolds numbers induce wider wake expansion and a larger axial velocity defect. This quantitative analysis will contribute to a clearer understanding of the scaling effects and help to design more efficient wind energy harvesters.

An ultra-high efficient micro combined heat and power cogeneration system based on gas combustion powered thermoelectric generator

People never stop seeking distributed, efficient, and multi-purpose energy technologies. A micro combined heat and power (CHP) cogeneration system based on gas combustion powered thermoelectric generator is designed and tested in this study to provide such a solution. A systematic controlling strategy, interlinking various aspects including power generation, temperature uniformity, heat collection and distribution via several passive and active controlling measures, is first proposed to simultaneously augment electric power, overall power generation efficiency and CHP efficiency. The developed CHP cogeneration system is featured by extraordinary high CHP efficiency (92.5 %), high electric power (75.6 W), and remarkable thermoelectric efficiency (4.44 %) through comprehensive optimizations of pin fin area, compensatory heat collection, and extract draft fan running parameter. Various parameters including input power, cooling method, and load resistance are explored to identify their influences on the generated electric power, heat collection, thermoelectric, overall power generation, and CHP efficiencies. The major contribution of the present study is to provide a concrete systematic controlling strategy to release the potential of each thermoelectric module (6.3 W per module). Moreover, the underlying controlling mechanism of the proposed strategy is revealed through in-depth discussions. It is found that decoupling the interdependence between power generation and heat collection, and applying appropriate compensatory heat collection are two essential logics to simultaneously augment electric power, overall power generation, and CHP efficiencies. Another contribution of the present work is the modularization of the developed CHP cogeneration prototype. A scale-up CHP system is manufactured and tested, confirming the reliability and equal scale magnification of modularization.

Topological beaming of light.

Nanophotonic light emitters are key components in numerous application areas because of their compactness and versatility. Here, we propose a topological beam emitter structure that takes advantage of submicrometer footprint size, small divergence angle, high efficiency, and adaptable beam shaping capability. The proposed structure consists of a topological junction of two guided-mode resonance gratings inducing a leaky Jackiw-Rebbi state resonance. The leaky Jackiw-Rebbi state leads to in-plane optical confinement with funnel-like energy flow and enhanced emission probability, resulting in highly efficient optical beam emission. In addition, the structure allows adaptable beam shaping for any desired positive definite profiles by means of Dirac mass distribution control, which can be directly encoded in lattice geometry parameters. Therefore, the proposed approach provides highly desirable properties for efficient micro-light emitters and detectors in various applications including display, solid-state light detection and ranging, laser machining, label-free sensors, optical interconnects, and telecommunications.