Extra Pump Research Articles

Magnon-mediated optical frequency comb in a cavity optomagnonical system

Generally, optical frequency combs (OFC) are generated through nonlinear effects in optical pumping, such as Kerr nonlinearity, the electro-optic effect, and second-order nonlinearity. Here, we propose an effective mechanism for generating OFC in a cavity optomagnonical system via the nonlinearity of magnon-photon coupling. Our results demonstrate that robust OFC can be achieved in this system when driven by effective nanosecond pulses in the non-perturbation regime. Notably, the addition of an extra microwave pump field can enhance magnon-photon coupling and reduce the system’s reliance on the optical pump field. Furthermore, the number and spacing of the OFC teeth can be adjusted by selecting appropriate experimental parameters. These findings contribute to a deeper understanding of the quantum and nonlinear properties of magnons and pave the way for the development of OFC devices in integrated optics and photonics.

Cross-dimensional multi-physics model and two-phase mass-transport enhancement for the hydrogen peroxide-based fuel cell

The direct liquid fuel cell utilizing hydrogen peroxide as an oxidant is considered to be the promising energy conversion technology, owing to its superior energy density and theoretical voltage. In the hydrogen peroxide-based fuel cells, the ever-changing two-phase mass transport and multi-component reaction processes resulting from the hydrogen peroxide self-decomposition exerts a pivotal influence on their performance. In this work, taken hydrogen peroxide self-decomposition into account, a cross-dimensional multi-physics model for the hydrogen peroxide-based fuel cell was proposed and developed to clarify the complex mechanisms of transports and reactions. In this ingeniously developed model, the multi-component reaction in the porous electrode is elucidated by a two-dimensional (2D) sub-model, the two-phase mass transport in the flow field is captured by a three-dimensional (3D) sub-model, and the one-dimensional (1D) correlation equation is served as a bridge between them. The uneven distribution of gas–liquid volume, velocity and current density and their relationships in fuel cell with serpentine flow field and dot matrix flow field were thus achieved. Furthermore, a novel gradient dot matrix flow field was developed to match the two-phase mass transport and multi-component reaction processes of hydrogen peroxide-based fuel cell. It is found that the continuously increasing pressure and velocity along flow path is balanced by the gradient-downsized ribs and the formation of large-volume oxygen bubbles is prevented by the gradient-densified ribs, achieving obviously uniformized current density distribution. Moreover, the gradient dot matrix flow field enables 54 % higher average hydrogen peroxide coverage contents (49 %) and 86 % lower average pressure drop (172 Pa) compared to the serpentine flow field, yielding 6.3 % higher peak power density (210 mW cm−2) and ultra-low extra pump power in fuel cell. This work will make contribution towards gaining profound insights into the intricate mechanisms underlying mass and charge transport, and offering invaluable guidance for the flow field design for the hydrogen peroxide-based fuel cells.

An energy saving strategy on the composite phase change material and spiral liquid cooling channel for battery thermal management

In order to ensure the safety and stability of the cooling system during the operation of the battery thermal management system combined with composite phase change material cooling and liquid cooling, it is usually necessary to continuously pump cooling water. It inevitably caused that the latent heat of composite phase change material could not be fully released and extra pump power was consumed. In the study, five different energy saving strategies were proposed and the energy efficiency ratio was defined to evaluate their cooling effects and energy saving. The effect of energy saving strategies on energy consumption of liquid cooling and latent heat utilization of composite phase change material was analyzed. The results show that III and V can meet their cooling requirements and have a high energy efficiency ratio. The screw pitch and cooling water flow rate in these two modes were investigated. The results show that the increase in screw pitch reduces the heat transfer efficiency, resulting in an increase in Tmax and ΔTmax, and ΔTmax exceeding the maximum range. Diminishing the cooling water flow will precipitate a rise in battery temperature, enabling the CPCM to operate at its maximum capacity and consequently decreasing ΔTmax. As a cooling water flow of 20 ml/min in III and V all can satisfy the cooling requirements. Additionally, the III was also competent when the cooling water temperature was raised from 25 °C to 35 °C.

Temperature analysis of extra vessel electromagnetic pump cooling for a Micro nuclear reactor with an electric power of 20 MW

Lead bismuth eutectic (LBE) is used as coolant for MicroURANUS, a small marine nuclear power plant, and this coolant is transported in the plant by an electromagnetic pump. Given the considerable heat generated by the electromagnetic pump, the cooling of the pump is essential. This study compared air cooling and water-cooling methods and found that the maximum temperatures during air and water cooling were 640 K and 372 K, respectively. These findings were utilized to design an electromagnetic pump with water-cooling. The maximum temperature of the pump was lower than the boiling point of water; thus, the pump did not require a separate pressurization. Consequently, the resistance problem of the coil and the deformation problem of the material caused by generated heat can be solved through water-cooling.

Self-synchronized temporal-spectral characterization system for revealing ultrafast fiber laser dynamics

Due to the electronic bottleneck limited real-time measurement speed of common temporal-spectral detection and the particle-like nature of optical soliton enabled nonrepeatable transient behaviors, capturing the ultrafast laser pulses with unknown times of arrival and synchronously characterizing their temporal-spectral dynamic evolution is still a challenge. Here, using the Raman soliton frequency shift based temporal magnifier and dispersive Fourier transform based spectral analyzer, we demonstrate a self-synchronized, ultrafast temporal-spectral characterization system with a resolution of 160 fs and 0.05 nm, and a recording length above milliseconds. The synchronized nonlinear process makes it possible to image full-filled temporal sub-picosecond pulse trains regardless of their arrival times and without extra pump lasers and photoelectric conversion devices. To demonstrate the significance of this improvement, a buildup dynamic process of a soliton laser with a complex breakup and collisions of multisolitons is visually displayed in the spectral and temporal domains. The soliton dynamic evolution processes observed by our characterization system are in one-to-one correspondence with the numerical simulation results. We believe this work provides a new multidimensional technique to break the electronic bottleneck to gain additional insight into the dynamics of ultrafast lasers and nonlinear science.

Self-parametric amplification of a bound-state dissipative soliton assisted by spectral filtering effect in the negative dispersion regime

Various striking nonlinear dynamics have been obtained from an ultrafast fiber laser. Herein, we first numerically demonstrate the self-parametric amplification of the bound-state dissipative soliton induced by the spectral filtering effect in the negative dispersion regime. The self-parametric amplification in our work manifests itself as optical spectrum intensity enhancement in the absence of extra pump light injection, which is resulted by the energy flowing within the laser field. Comparing the ultrafast fiber laser system without bandwidth filter and those with 8-nm or 10-nm bandwidth filters respectively, a stable spectrum and two spectral periodic evolutions can be observed, which demonstrates that the spectral filtering effect plays a key role in the self-parametric amplification process. These findings can provide new insights into the complex nonlinear behavior of bound-state dissipative solitons in the ultrafast fiber lasers.

Optimization of an extra vessel electromagnetic pump for Lead–Bismuth eutectic coolant circulation in a non-refueling full-life small reactor

This study presents an optimal design of the coolant system of a non-refueling full-life small reactor by analyzing the space-integrated geometrical and electromagnetic variables of an extra vessel electromagnetic pump (EVEMP) for the circulation of a lead–bismuth eutectic (LBE) coolant. The EVEMP is an ideal alternative to the thermal-hydraulic system of non-refueling full-life micro reactors as it possesses no internal structures, such as impellors or sealing structures, for the transportation of LBE. Typically, the LBE passes through the annular flow channel of a reactor, is cooled by the heat exchanger, and then circulates back to the EVEMP flow channel. This thermal–hydraulic flow method is similar to natural circulation, which enhances thermal efficiency, while providing a golden time for cooling cores in the event of an emergency. When the forced circulation technology of the EVEMP was applied, the non-refueling full-life micro reactor achieve an output power of 60 MWt, which is higher than that achievable via the natural circulation method (30 MWt). Accordingly, an optimized EVEMP for Micro URANUS with a flow rate of 4196 kg/s and developed pressure of 73 kPa under a working temperature of 250 °C was designed.

Antioxidant Profiling of Ginger via Reaction Flow Chromatography

Reaction flow (RF) chromatography is a powerful and efficient approach that utilizes conventional high-performance liquid chromatography (HPLC)–ultraviolet (UV)–visible detection. This technique exploits a novel column end-fitting and an extra HPLC pump that delivers a reagent specific for selective detection, in particular the antioxidant profiling of natural products. This study employed RF for the first time to identify antioxidants in a commercial ginger sample. This demonstrated the previously validated assay's ease and power to extract information about the natural product's antioxidant properties. Due to the simplicity involved with data analysis and peak matching process, the following information was revealed between the chemical and antioxidant profiles: three of the strongest antioxidant activity peaks in the ginger sample (593 nm) did not correlate with the three most abundant chemical profile peaks (UV absorbance at 254 and 280 nm); the ratio of seven antioxidant peaks may be potentially used for food authenticity purposes, and future research should target these peaks for the early discovery of novel antioxidants sourced in ginger. Utilization of this previously validated assay provided the resolution of numerous peaks in the ginger extract and information associated with their antioxidant attributes and chemical abundance. This approach is more informative than total antioxidant assays that lack compound specificity information. Furthermore, it is superior to mass spectrometric (MS) assays that cannot evaluate each compound's antioxidant strength, and does not involve the expense involved in the acquisition and maintenance of the MS detection hardware, and does not require the high level of expertise needed to conduct the MS data analysis.

Modelling and analysis of extra vessel electro magnetic pump for a small modular lead-bismuth fast reactor

The model of the EVEMP (Extra Vessel Electro Magnetic Pump) with a mass flow of 5000 kg/s and a developed pressure of 15000 Pa in the 350 °C operating temperature has many advantages as a coolant circulation pump for the Micro URANUS.Micro URANUS is an SMR with a rated output of 60 MWt which is abbreviated as ‘Micro Ubiquitous, Rugged, Accident-forgiving, Nonproliferating, and Ultra-lasting Sustainer’. Micro URANUS has a six-angle grid core as a pool type fast reactor using LBE, which is chemically stable as a coolant and can achieve a fast neutron spectrum. It is necessary to utilize natural circulation for the reactor to run without pumps even during normal operation, as well as accident situations. However, natural circulation was calculated to be only possible in the current design up to an output of 30 MWt as the size of the power source is very small compared to that given by the pump. In order to install pumps for enhanced output in Micro URANUS with these very small sizes and special structures, installation of EVEMP using the concept of an electromagnetic pump that is easy to free up space and operates in contactless ways is essential, and this is used to design enhanced power up to 60 MWt. The relationship of performances and design factors are analysed for the optimization of the EVEMP, derives data such as P-Q characteristics, input power changes, and efficiency changes depending on the different input power conditions of the EVEMP are predicted.

Simultaneous determination of acetamiprid and 6-chloronicotinic acid in environmental samples by using ion chromatography hyphenated to online photoinduced fluorescence detector.

This study aims to introduce a simple, sensitive, and cost-effective method for the simultaneous determination of acetamiprid and its main metabolite 6-chloronicotinic acid in environmental samples by using a nonsuppressed ion chromatography hyphenated with an online postcolumn photoinduced fluorescence detection system. The fluorescence detector wavelengths λex /λem =257/382nm was set for up to 6.0min for acetamiprid, while λex /λem =231/370nm programmed for 6-chloronicotinic acid for the rest of the analysis time. Both samples were treated by applying miniaturized quick, easy, cheap, effective, rugged, and safe method before the separation of analytes on an IonPac® AS11-HC column by pumping 40mM NaOH having minuscule content of acetonitrile (5%, v/v) as an eluent. Both intrinsically nonfluorescent analytes were turned-on by online postcolumn photoinduced derivatization, avoiding the need for complex chemical derivatization or addition of a postcolumn extra pump. The developed method was appraised for the analysis of environmental samples, exhibiting excellent linearity (0.050-10μg/mL) with a correlation coefficient greater than 0.9993 for both analytes. Whereas, obtained limit of detection (0.025-0.0072μg/mL), recoveries (98.02-116.00%), and inter- and intraday precision (≤3.02 %) were satisfactory for both compounds in environmental samples.

Evaluation of ground source heat pump system’s enhancement by extracting groundwater and making artificial groundwater velocity

This study used moving line source technique as a practical approach to simultaneously determine effective thermal conductivity, groundwater velocity and borehole resistance. It mainly focused on the applicability of this approach for observing the effect of groundwater extraction, in particular for ungrouted ground heat exchangers. The thermal response tests were carried out for different ground heat exchangers at two sites on the Akita University campus, northern Japan. The test conditions varied, based on different borehole filling condition (grouted/ungrouted), heat loads and presence of an extra pump for groundwater extraction. The hydro-thermal parameters of the ground were determined by a MATLAB code, especially for consideration of the effect of artificial groundwater velocity under a special test, where a water pump extracts the groundwater from the casing of the borehole during the test. This method can estimate the groundwater velocity and the effective thermal conductivity of the soil by reproducing the temperature distribution in the well and minimizing the root mean squared error between the calculated results and the measured data. As a result, the groundwater velocity and thermal conductivity calculated by this method improved to 205.3 cm/day and 7.48 W/m K, respectively, due to presence of the external pump, whereas the undisturbed groundwater velocity in the other cases without pumping was estimated in the range of 15 to 16 cm/day. Furthermore, the minimum groundwater velocity and thermal conductivity were reported for the grouted well as being equal to 10.79 cm/day and 1.16 W/m K, respectively.

Voltage Comparator With 60% Faster Speed by Using Charge Pump

This brief proposes a novel comparator to greatly increase its comparison speed while not degrading its noise performance. This comparator is well suited for high-speed high-resolution SAR ADCs. Its structure is based on the classic Miyahara’s two-stage comparator with the addition of only an extra charge pump. This simple modification greatly accelerates both the second-stage amplification phase and the regeneration phase, leading to significantly increased comparison speed. Meanwhile, the noise performance is not degraded, because the input pair transconductance of the second stage is increased while its integration time is decreased. For fair comparison, both the proposed comparator and the classic Miyahara’s comparator are implemented in the same 40nm CMOS process. Measurement results show that the proposed comparator speed is faster by 60% compared with the classic Miyahara’s comparator, while the input-referred noise is similar.

Experimental and numerical study of PCM thermophysical parameters on lithium-ion battery thermal management

Lithium-ion battery (LIB) nowadays plays a key role as one of the most widely used energy storage technologies such as the application in electric vehicles. Thermal management critically affects the performance of LIB. Phase change cooling using phase change material (PCM) has become a promising method due to its high latent heat and no need to consume extra pump power. In this study, thermal performance of a battery module with 25-parallel 18650 lithium-ion battery has been numerically and experimentally investigated by adopting phase change cooling with PCM. Firstly, the internal resistance of the unit cell has been experimentally tested to build up the heat generation model. Based on the heat generation model and heat transfer model, the effects of PCMs thermophysical parameters including thermal conductivity, latent heat and porosity are investigated when they are applied in the thermal management of designed LIB module. The results indicate that the higher thermal conductivity and latent heat lead to better thermal management performance comprehensively considering the maximum temperature and temperature uniformity of LIB module. Results also illustrate that thermal management performance increases very slightly when the thermal conductivity and latent heat attain a relatively high value. As for the porosity of paraffin/metal foam, an optimal value of 94% exists to achieve the lowest maximum temperature for LIB module.

Streamlining the Power Generation Profile of Concentrating Solar Power Plants

A scheme to streamline the electric power generation profile of concentrating solar power (CSP) plants of the parabolic trough collector (PTC) type is suggested. The scheme seeks to even out heat transfer rates from the solar field (SF) to the power block (PB) by splitting the typical heat transfer fluid (HTF) loop into two loops using an extra vessel and an extra pump. In the first loop, cold HTF is pumped by the cold pump from the cold vessel to the SF to collect heat before accumulating in the newly introduced hot vessel. In the second loop, hot HTF is pumped by the hot pump from the hot vessel to a heat exchanger train (HXT) to supply the PB with its heat load before accumulating in the cold vessel. The new scheme moderately decouples heat supply from heat sink allowing for more control of heat delivery rates thereby evening out power generation.

Energetic and exergetic investigation of a novel refrigeration system utilizing ejector integrated subcooling using different refrigerants

Increase in coefficient of performance of refrigeration systems is eminently important for various applications such as household refrigerator, tumble dryer, and more in practical applications. A new ejector subcooling system is described and investigated numerically without using an extra pump or compressor. After condenser, some part of the liquid (by-pass refrigerant) is expanded so that its temperature could be lower than the intended subcooling temperature. By using this by-pass refrigerant, the main flow of the refrigerant is subcooled. After evaporation, the by-pass refrigerant is expanded using an ejector. Seven different refrigerants are considered as working fluids (namely; R32, R1234yf, R290, R134a, R717, R600a and R245fa). R1234yf, R290, R600a and R717 are considered as low global warming potential refrigerants in European Union regulation. For each refrigerant, the values of coefficient of performance, relative increment in coefficient of performance and exergy efficiencies are calculated and demonstrated graphically for different condenser temperatures between 30°C/70°C and evaporator temperatures between −20°C/10°C. Results show that the best performance is obtained for R1234yf with an increment of about 20% in coefficient of performance and 18% in exergy efficiency. These efficiencies can be higher or lower approximately by 3% using ejector with higher or lower component efficiencies.

Determination of nitenpyram and 6-chloronicotinic acid in environmental samples by ion chromatography coupled with online photochemically induced fluorescence detector.

A simple, cost-effective, sensitive, and quick method for the determination of nitenpyram and its metabolite 6-chloronicotinic acid in environmental samples was developed by coupling an ion chromatograph with a fluorescence detector and a post-column photochemical reactor. This developed analytical method involved a rapid sample extraction by modified and miniaturized quick, easy, cheap, effective, rugged, and safe method followed by isocratic ion chromatographic separation of nitenpyram and 6-chloronicotinic acid into an IonPac™ AS11-HC column protected by IonPac™ AG11A guard column by running 30mM NaOH + 10% acetonitrile mobile phase. A homemade post-column photochemical reactor was also integrated with the ion chromatographic system for online transformation of both analytes into their respective highly fluorescent photoproduct in basic media without using an extra pump. The developed method was validated by following SANTE/11945/2015 guidelines on analytical quality control and validation procedures. The method showed a good linear response (r>0.999), improved limit of detection (0.101-0.132μg/L), minimum or no matrix effect, excellent recoveries (90.2-100.10%) and relative standard deviations were found to be ≤6.50%.

Polyethylene glycol coating for hydrophilicity enhancement of polydimethylsiloxane self-driven microfluidic chip

The hydrophilic microfluidic chip that can self-actuate fluidic flow effectively with no extra pump is an important device for bio lab-on-a-chip (LOC) application. Polydimethylsiloxane (PDMS) is a common material for bio-microfluidic chip but suffers from hydrophobic surface problem. In this article, the surface modification of PDMS material for long-term hydrophilicity improvement has been studied by O2 plasma and polyethylene glycol (PEG) coating. Three kinds of surface treatment namely the O2 plasma treatment, PEG coating and O2 plasma followed by PEG coating were performed for hydrophilic enhancement on pristine PDMS. The contact angle measurement was used for examining hydrophilic duration after treatment. The contact angle of pristine PDMS is hydrophobic around 100°±3°. Using only O2 plasma treatment made the contact angle of PDMS below 10° initially but its hydrophobicity recovered quickly after 2h that hindered practical application. Adding PEG coating on the O2 plasma treated PDMS surface can make hydrophilic behavior retained longer than 400h. The Fourier transform infrared spectrometer and contact angle variation were used for identifying the evolution of hydrophilicity enhancement. The cross-form microchip was used for testing the self-driven flow of rhodamine droplet into the microchannel successfully. This method is low-cost, disposable and easy to integrate with the microfluidic LOC system.

Parametric strong mode-coupling in carbon nanotube mechanical resonators.

Carbon nanotubes (CNTs) have attracted much attention for use in nanomechanical devices because of their exceptional properties, such as large resonant frequencies, low mass, and high quality factors. Here, we report the first experimental realization of parametric strong coupling between two mechanical modes on a single CNT nanomechanical resonator, by applying an extra microwave pump. This parametric pump method can be used to couple mechanical modes with arbitrary frequency differences. The properties of the mechanical resonator are detected by single-electron tunneling at low temperature, which is found to be strongly coupled to both modes. The coupling strength between the two modes can be tuned by the pump power, setting the coupling regime from weak to strong. This tunability may be useful in further phonon manipulations in carbon nanotubes.

Broadband Compensation of Dispersion in APL Using OPC Based on DFB Semiconductor Lasers

A broadband chromatic dispersion (CD) compensation scheme using optical phase conjugation (OPC) based on a DFB semiconductor laser is proposed and experimentally demonstrated in analog photonic links (APLs). The DFB laser acts as a nonlinear medium to induce four-wave mixing and a pump laser simultaneously. Compared with the conventional OPC based on a semiconductor optical amplifier or a dispersion-shifted fiber, an extra pump laser is no longer required. Experimental results show that the power fading caused by the CD in a 50.4-km APL can be compensated with a 3-dB bandwidth up to 33 GHz. Meanwhile, the spur-free dynamic range is enhanced with 12.6 dB · Hz 2/3 ; the transmission performance is also improved.

Capillary force pumping fluid for glucose oxidase enzymatic fuel cells

Micro-fluidic channel plate for self-pumping glucose oxidase enzymatic fuel cell was designed and fabricated. Fuel was driven into the fuel cell by a capillary force without any extra pump. Fuel cell structure design included both end plates and micro-fluidic flow channel plate. Three reservoirs are fabricated onto the end plate. According to the experimental analysis, the cathode and anode flow rate were less than ideal flow rate. Anode and cathode flow rate were 0.499 µl.s−1 and 0.764 µl.s−1, respectively. And the capillary driven liquid efficiency of anode and cathode flow field was 36 % and 53 %, respectively. The result of Tafel test for self-pumping fluid enzymatic fuel cell showing a power output 0.534 mW.cm−2 (111.217 mW.cm−3) was achieved. Comparing to the active pumping method, the passive (self-pumping) method showed a lower output power. However, the current output performance of long term experiments at a constant voltage of 0.42 V indicated that the self-pumping fluid enzymatic fuel cell may work stably under a continuous fuel supply. It provides a solution for bio-pumping power source different from current power generators.