Total Pump Research Articles

On-chip power efficient MHz to GHz tunable Brillouin microwave photonic filters

Stimulated Brillouin scattering (SBS) offers optically tunable, narrowband gain and loss resonances, which makes it ideal for optical filtering and signal processing applications. However, broadband filters utilizing Brillouin scattering typically necessitate multiple pump sources or linear frequency modulated waveforms, which necessitate the use of overall high pump powers to achieve broadband and multi-band filter configurations. To overcome the trade-off between bandwidth and power consumption, we introduce an on-chip broadband bandpass filter scheme leveraging the SBS response and the concept of radio frequency interference. We present the MHz to GHz reconfigurable microwave photonic filters on a chip. The bandwidth is tunable from 30 MHz to 1.2 GHz at a total pump power of only 15 dBm, corresponding to a figure of merit (maximum bandwidth/pump power) improvement of a factor of 25 compared to previously reported work. Furthermore, the filter exhibits frequency tuning capabilities ranging from 10 to 40 GHz (X to Ka-band) and can be configured from single- to multi-bandpass filter responses and switched from bandpass to bandstop.

Numerical Modeling of a Primary Heat Exchanger in sCO2 Power Cycles for Thermal Energy Storage Systems

Abstract Renewable energy sources are the key for long-term decarbonization of energy. However, the intermittent nature of renewables does not always meet the energy demand in the electrical grid. Thus, electrical heated thermal energy storage systems (TES) coupled with sCO2 power cycles are investigated at Helmholtz-Zentrum Dresden-Rossendorf as a possible solution to balance this mismatch. In this study, a printed circuit heat exchanger (PCHE) is considered as candidate for the 1 MW primary heat exchanger, given the mechanical challenge induced by drastic pressure difference between the hot fluid of the TES and the cold fluid of the power cycle. The present work consists of two parts, one elaborates a one-dimensional (1D) model in order to optimize the PCHE regarding the pump power required to compensate the pressure loss. It was found that the hot fluid coming from the TES accounts for 80% of the total pump power after optimization because of its low density and its high mass flow rate. Furthermore, three-dimensional simulations by computational fluid dynamics (CFD) were done and compared to the results from the 1D model to ensure its validity. It was observed that the results from the 1D model and the CFD simulations are consistent, with a slight potential deviation in the calculation of the pressure profile.

Quantifying uncertainty in the contribution of mesopelagic fishes to the biological carbon pump in the Northeast Atlantic Ocean

Abstract Mesopelagic fishes may contribute substantially to marine carbon export and sequestration. However, uncertainty in this contribution due to limited precision of mesopelagic biomass and bioenergetic rate estimates has not been thoroughly quantified for any study site. Datasets that can confront these challenges are rare, particularly for comparing fish-mediated carbon flux to other biological carbon pump pathways. Using data from a unique three-ship expedition in spring 2021 in the subarctic Northeast Atlantic Ocean, we compare carbon transported by adult fish, zooplankton, and sinking particles, and calculate uncertainty in the relative contribution of fishes. Results indicate biomass- and bioenergetic-based uncertainty contributed roughly equally to variance in estimated carbon transport. The plausible range of mesopelagic fish carbon flux spans an order of magnitude: 1.6–21 mg C m−2 d−1 to 200 m depth and 0.52–9.6 mg C m−2 d−1 to 500 m. Fishes contributed ∼0.52%–18% at 200 m to the total biological carbon pump, and ∼0.43%–13% at 500 m. Of the fish-mediated carbon transport to 200 m, ∼8%–30% is sequestered on climate-relevant time scales (>100 years). This reinforces that carbon transport should not be conflated with carbon sequestration. These findings have implications for prioritizing future empirical measurements, evaluating trade-offs in fisheries management, and understanding the role of fishes in the biological carbon pump.

10 W, 2 mJ-level ns all-fiber amplifier at 2.8 µm.

In this Letter, we demonstrate a single-stage erbium-doped fluoride fiber amplifier composed of two spliced large core fibers with respective diameters of 85 and 130 µm. An optical parametric generator (OPG) operating at a 5 kHz repetition rate, and providing ∼2 ns pulse duration, and an average output power of 500 mW at a wavelength of 2.8 µm was used as a seed source. This nanosecond amplifier configuration achieved an average output power of 10 W with a record pulse energy of 2 mJ, corresponding to 1 MW of output peak power. The maximum slope efficiency of this hybrid amplifier is 21% with respect to the total incident pump power at 940 nm. The presented master-oscillator power-amplifier (MOPA) configuration shows its potential for further power and energy scaling.

Beyond the Wedge: Impact of Tidal Streams on Salinization of Groundwater in a Coastal Aquifer Stressed by Pumping and Sea‐Level Rise

AbstractSaltwater intrusion (SWI) is a well‐studied phenomenon that threatens the freshwater supplies of coastal communities around the world. The development and advancement of numerical models has led to improved assessment of the risk of salinization. However, these studies often fail to include the impact of surface waters as potential sources of aquifer salinity and how they may impact SWI. Based on field‐collected data, we developed a regional, variable‐density groundwater model using SEAWAT for east Dover, Delaware. In this location, major users of groundwater from the surficial aquifer are the City of Dover and irrigation for agriculture. Our model includes salinized marshland and tidal streams, along with irrigation and municipal pumping wells. Model scenarios were run for 100 years and included changes in pumping rates and sea‐level rise (SLR). We examined how these drivers of SWI affect the extent and location of salinization in the surficial aquifer by evaluating differences in chloride concentration near surface waters and the subsurface freshwater‐saltwater interface. We found the presence of the marsh inverts the typical freshwater‐saltwater wedge interface and that the edge of the interface did not migrate farther inland. Additionally, we found that tidal streams are the dominant pathways of SWI at our site with salinization from streams being exacerbated by SLR. Our results also show that spatial distribution of pumping affects both the magnitude and extent of salinization, with an increase in concentrated pumping leading to more intensive salinization than a more widely distributed increase of the same total pumping volume.

Simulation and experiment of CRAFT NNBI cryopump

The cryogenic vacuum system is an important subsystem of Comprehensive Research Facility for Fusion Technology Negative Neutral Beam Injector, which provides vacuum environment support for various experiments related to the beam generation and transport process. In the paper, a simulation and experimental study of the Comprehensive Research Facility for Fusion Reactor Negative Neutral Beam Injector (CRAFT NNBI) cryopump performance has been carried out. The Beam Line Vessel (BLV) and its components are modeled by Solidworks, the pressure distribution, gas molecular velocity distribution and adsorption uniformity of the crysorption pump in the BLV are analyzed by simulation using the Molflow software, at the same time, the performance of the south cryopump is tested experimentally using in-situ measurement method. The simulation results show that the average pressure near the Neutralizer is 8.5*10-3 Pa, the average pressure near the Electrical Residual Ion Dump (ERID) is 8*10-3 Pa, and the average pressure near the Calorimeter is 9*10-3 Pa. The adsorption percentage fluctuates around 12%, which indicates that single structure plays the function of adsorption efficiently, the theoretical pumping speed of the south cryopump on H2 was calculated to be 7.34*105 L/s, total theoretical pumping speed of two cryopumps can reach 3.67*106 L/s. The experimental results showed that when the south cryopump was operation, the pressures near the Neutralizer were 2.8*10-2 Pa, the pressures near the ERID were 2.7*10-2 Pa, and the pressures near the Calorimeter were 7*10-3 Pa, the actual pumping speed of the south cryopump on H2 was 6.37*105 L/s, total actual pumping speed of two cryopumps can reach 3.1*106 L/s.

CFD-DEM investigation of centrifugal slurry pump with polydisperse particle feeds

Polydisperse particle feed into centrifugal slurry complicates hydraulic performance and wall erosion but is poorly understood. This paper presents a numerical study of a centrifugal slurry pump, focusing on the effect of particle size distribution (PSD) using the combined computational fluid dynamics and discrete element method (CFD-DEM). It incorporates rigid impeller rotation and wall erosion. On this basis, the hydraulic and erosion model validity is verified by clear water performance and jet erosion test, respectively. Additionally, this CFD-DEM model is compared with the dense discrete phase model (DDPM), demonstrating more precise erosion prediction as its fully resolved particle-particle interactions. Generally, total pump erosion severity intensifies when the PSD is broadened. Compartment-wise, it indicates the necessity of tailoring flow structure to enlarge drag force, therefore, mitigate particle aggregation in the impeller. This in-house CFD-DEM model is promising for addressing particle-fluid flow problems in centrifugal pumps or coupling with data driven method.

Hundred-watt Ho:YAG oscillator pumped by high-power Tm:YLF laser with orthogonal cylindrical lenses spot shaping

A hundred-watt, linearly-polarized Ho:YAG oscillator, pumped by a 200 W, home-made and s-polarized Tm:YLF laser, was demonstrated. By utilizing a combination of a half-wave plate (HWP) and a thin-film polarizer (TFP), the Tm:YLF laser was split into two orthogonally polarized parts. Each part was significantly reshaped by a system of orthogonally arranged cylindrical lenses and subsequently used to dual-end pump the oscillator. With a total incident pump power of 183 W, a continuous wave (CW) output power of 101 W at 2.1 μm was achieved, with corresponding slope efficiency and optical-to-optical conversion efficiency (OOCE) of 61.6 % and 55.2 %, respectively. Additionally, the beam quality factors, measured in the x and y directions, were 1.59 and 1.35, respectively. Finally, under Q-switched operation at a repetition rate of 20 kHz, a maximum output power of 97 W was achieved, with a corresponding pulse width of less than 34 ns. The central wavelength of the laser was measured to be 2090.2 nm.

RANCANG BANGUN SISTEM PENDINGIN UNTUK MESIN BUBUT BV 20

The purpose of this study is to design and create a cooling system on the BV 20 lathe. The method used in this study is the design method by conducting direct design manufacturing based on the condition of the BV 20 lathe and designs by calculating the total head pump and pumping heading. The manufacturing process is carried out starting from the identification of working drawings and identification of components using existing tools or machines, ordering and procuring the market for other components. Then it can be produced a cooling system for a BV 20 lathe with a 3 watt pump. Keyword designs, cooling system, lathe BV 20

Design of Automatic Flood Control System in Kulon Progo, Special Region of Yogyakarta, Indonesia

The construction of Yogyakarta International Airport has resulted in land use changes and increased the topography in the area by up to 9 m, which has led to potential flooding. A spatial analysis was conducted on the flow direction after the airport's construction, specifically in the West Carik watershed. It was discovered that the flow direction was uncertain and trapped upstream of the airport. A polder system with automation is proposed as a solution to the drainage problem. An automation system is designed for pump operation with the objective of improving efficiency. The system is expected to reduce the volume of water in the polder by reducing human involvement and providing ease in monitoring. The results of hydrological analysis with a 50-year return period flood resulted in a design flood discharge of 11.73 m3/s. The polder has a storage capacity of 63,312 m3, a depth of 4 m, and a surface area of 1.58 ha. It requires a total pump capacity of 8.4 m3/s, consisting of three pump units, with one unit having a capacity of 1.8 m3/s and two units with 3.3 m3/s. One additional pump with a capacity of 3.3 m3/s is also planned as a backup pump. The pump automation system simulation employs an Arduino UNO as the controller, water level sensor, and relay. This system successfully fulfills the desired operational system for the pump. In the actual implementation, a Programmable Logic Controller (PLC) is required as the controller, with water level sensors, relays, and contactors as inputs and outputs.

Generation of a red-green-blue laser by stimulated Raman scattering of ethanol.

In this paper, we report an efficient red-green-blue (RGB) laser based on the stimulated Raman scattering (SRS) of ethanol. The wavelengths of the three-color laser are 631, 532, and 447 nm, respectively, and the gamut space that can cover is 116% of the Rec. 2020 standard gamut in the CIE1976 color space. The maximum output energy of the RGB laser was 595.9 µJ under the total pump energy of 1.56 mJ, which corresponds to an optical conversion efficiency of 38.2%. By adjusting the energy ratio of different wavelengths, a white laser output with a maximum output energy of 544.8 µJ is achieved, corresponding to a conversion efficiency of 34.9%. To the best of our knowledge, this is the first time that an RGB laser has been realized based on liquid SRS. It provides a simple, practical route for efficiently obtaining RGB and white lasers, which may find important applications in many fields like laser display, atmospheric monitoring, and medical beauty.

Modeling and analysis of single-mode widely tunable all-fiber Ho-doped CW master oscillator power amplifier system

We report the design of an all-fiber single-mode polarization maintaining widely tunable Ho-doped master oscillator power amplifier (MOPA) system operating in the wavelength range of 2005-2135 nm based on a pre-amplifier and two power amplification stages. The single clad Ho-doped active fibers in the ring cavity based master oscillator, pre-amplifier, and power amplifiers are pumped using 1950 nm semiconductor laser diode pump sources. The amplification of the MOPA system is investigated over the entire spectral range of 2005-2135 nm. The highest output power achieved by the continuous wave (CW) Ho-doped MOPA system is 43 W at a wavelength of 2028.6 nm using pump power of 20 W with power conversion efficiency (PCE) of 90% for second power amplifier while the total pump power of Ho-doped MOPA system is 45 W. Optical bandpass filters (OBPFs) are employed between different stages of MOPA system to enable amplification over the wider spectral range of 2005-2135 nm by suppressing the amplified spontaneous emission (ASE). Not using OBPFs results in amplification that is limited to the spectral range of 2045-2130 nm. Therefore, a penalty of 45 nm can be avoided at the expense of using the OBPFs between different stages of MOPA system. This flexible MOPA system can be used in multiple applications, especially for space-borne high power transmitters operating in atmospheric transmission windows.

Modeling optimization design and amplification characteristics of O-band irregular Bragg bismuth-doped fiber amplifier

In recent years, O-band bismuth-doped fiber amplifier (BDFA) have been rapidly developed due to the fluorescence properties of bismuth-doped glass in the near-infrared (NIR) band, while there are still few studies on bismuth-doped fibers (BDF) with large mode fields as of now. In addition, although the use of a double-pass structure on the amplifier can lead to gain improvement, this also deteriorates the noise figure (NF). Therefore, the study of bismuth-doped fibers with large mode-field areas is a promising path to develop high-performance BDFA. In this work, taking a commercial bismuth-doped fiber as an instance, we first measured the refractive index distribution of the BDF in the O-band using a self-developed fiber refractive index tester, and thereby obtained its actual mode-field area. Then, based on this we further propose an irregular Bragg bismuth-doped fiber with the refractive index growing layer by layer. The results suggests that the effective mode-field area of this fiber reaches 401 um2 at 1320 nm, which is nearly 5.8 times that of a common single-mode BDF. Finally, we performed numerical simulations of the amplification performance based on this fiber. Under the condition of total pumping power of 8 W, the signal with −20 dBm input power obtains a gain of more than 54 dB and an NF of less than 5 dB at 1320 nm wavelength. This work demonstrates the great potential of this Bragg bismuth-doped fiber as an O-band high-gain amplifier and high-power laser.

Effects of Heat Exposure and Ice Slurry Ingestion on Risk-Taking Behavior in Healthcare Workers.

Healthcare workers (HCWs) wearing personal protective equipment (PPE) experience physiological strain that can impair motor and psychological functions, potentially affecting patient care. We assessed the effects of heat exposure on maximal strength and risk-taking behavior among PPE-wearing HCWs and the efficacy of ice slurry to alleviate adverse effects. Seventeen HCWS completed two experimental trials in a crossover design, consuming 5 g·kg -1 of body mass of ambient drink (AMB) or ice slurry (ICE) before donning PPE and undergoing 2 h of simulated decontamination exercise (wet-bulb globe temperature (WBGT): 25.9°C ± 0.8°C, PPE microenvironment WBGT: 29.1°C ± 2.1°C). Body core temperature ( Tc ), heart rate (HR), chest skin temperature ( Tsk ), ratings of perceived exertion (RPE), thermal sensation (RTS), maximal voluntary contraction (MVC), risk-taking behavior (balloon analogue risk-taking task (BART)), and salivary cortisol were assessed. Predrinking to postdrinking ∆ Tc was greater in ICE (-0.2°C ± 0.1°C) than AMB (-0.0°C ± 0.1°C, P = 0.003). Post-drinking RTS was lower in ICE (2.7 ± 1.2) than AMB (4.1 ± 0.4, P < 0.001). ICE and AMB had similar Tc and HR (both P > 0.05), but Tsk was lower in ICE than AMB ( P = 0.049). A lower MVC (30.3 ± 6.7 vs 27.4 ± 4.9 kg, P = 0.001) and higher BART-adjusted total pump count (472 ± 170 vs 615 ± 174 pumps, P = 0.017) was observed pretrial to posttrial in AMB but absent in ICE (both P > 0.05). Salivary cortisol was similar between trials ( P = 0.42). Heat-exposed PPE-wearing HCWs had impaired maximal strength and elevated risk-taking behavior. This may increase the risk of avoidable workplace accidents that can jeopardize HCWs and patient care. Ice slurry ingestion alleviated these heat-related impairments, suggesting its potential as an ergogenic aid.

Heating performance of a vapor compression heat pump cascaded with a thermoelectric heat pump

Air source heat pumps (ASHPs) are widely utilized for heating and cooling in residential buildings; however, their effectiveness in heating mode is compromised during extreme weather conditions. Extensive research endeavors have been undertaken to develop, test, and assess a cost-effective vapor compression ASHP suitable for cold climate regions. This study takes an innovative approach by developing component and system prototypes for a cold climate heat pump. This design combines a thermoelectric heat pump (TEHP) with a traditional residential split ASHP to augment heating capacity in low ambient temperature conditions. The component and system prototypes underwent experimental testing in the psychrometric chambers. The experimental findings revealed a 13.6 % to 13.7 % increase in total heat pump heating capacity, accompanied by a 3.1 % to 5.0 % decrease in the coefficient of performance (COP) at ambient temperatures of −15 °C and −19 °C, when compared to the original ASHP. The COP of the TEHP is relatively constant, ranging from 1.63 to 1.76. This prototype offers a solution to address the challenges associated with reduced heat pump capacity at low ambient temperatures. The experimental results indicated that the lower the ambient temperature, thermoelectric heat pump auxiliary heating can increase the heating efficiency 60 % in comparison to electric resistance.

In situ effective pumping speed measurements as a tool for non-evaporable getter activation and saturation monitoring

We have developed method of in situ effective pumping speed measurements based on injecting finite gas pulse into a vacuum volume and subsequent recording of pressure response using a Residual Gas Analyzer (RGA). The pressure burst caused by injected gas pulse falls exponentially in time and the exponential coefficient of such pressure decay is proportional to total effective pumping speed of all vacuum pumps acting on vacuum chamber volume. The effective pumping speed can be extracted from the dependence of injected gas species pressure vs time recorded by an RGA. Non-Evaporable Getters (NEGs) are widely used in multiple ultra and extremely high vacuum devices and applications during the last several decades. Areas of NEG applications were recently expanded into vacuum devices with relatively high-pressure levels (up to 10−7 Torr) by the invention of high capacity ZAO NEG which can be operated at elevated temperatures. The intrinsic property of all NEG-based vacuum pumps is the reduction of their pumping speed, called “NEG saturation”, after an extended period of operation. Typical time interval for such process can span from about a month and up to a few years depending on NEG type, vacuum level of NEG pump operation, and residual gas content. After that, the NEG pump will require a re-activation cycle to restore its pumping speed close to the initial value. For many applications it is difficult to realize what is the current pumping speed of NEG pump is and when the pump should be re-activated. A method for in situ effective pumping speed measurements developed in this study can be used as a tool for NEG-based pump activation and saturation monitoring. Application of such an approach to monitor pumping status of NEG pumps was utilized and will be continually used at Extended EBIS which was recently developed and commissioned for Relativistic Heavy Ion Collider (RHIC) and future Electron Ion Collider (EIC). The results obtained during commissioning are presented and discussed.

Analysis of seawater intrusion triggered under different pumping well layout schemes based on a numerical model

AbstractSeawater intrusion (SWI) is a consequence of communication between the ocean and inland groundwater entailed by overexploitation and has been a global issue harming production, life and ecology in coastal regions. This paper established a numerical model to identify SWI features in a wider space under different pumping‐well layouts based on the number of wells (N), distance between the coastline and wells (Dcw), and distance between wells (Dww) and further researched the influence of the location of the screen (Ls) and calculated S as an index inferring the SWI degree. An evaluation index (EI) was proposed considering two contradictory parameters: the corresponding total critical pumping rate (Qc) indicated the critical situation in which saltwater was almost pumped, played a good role as the resource function, and S referred the negative environmental impact. Sensitivity analysis was performed to explore the relationship between the evaluation indexes and the parameters of pumping well layouts. The results revealed how seawater intruded inland groundwater under different pumping well layouts and the anthropogenic impact factors influencing the SWI process. Sensitivity analysis verified that Dcw was the key factor in optimizing pumping well layouts to maximize the quantity of groundwater resources and minimize the environmental damage of SWI. Research on Ls revealed that a higher location of the screen of the well could effectively abate SWI. This research fully explained SWI characteristics under different pumping well layouts and proposed the key factors during coastal groundwater exploitation work, which enhanced the understanding of SWI and contributed to the arrangement of real‐world water pumping activities in coastal regions.

Confined aquifer dewatering optimization with a modified simulation–optimization method capable of determining the optimal well screen length and depth

Simulation-optimization methods are widely used in dewatering optimization. However, traditional simulation–optimization methods do not address the optimization of well screen length and depth. This study proposes a modified simulation–optimization method for confined aquifer dewatering optimization, which is capable of determining the optimal screen length and depth. The proposed method is based on the linear programming method, and the multivariate adaptive regression splines method is also introduced to develop the prediction model for the parameters required in the linear programming model. A hypothetical case of deep excavation dewatering was optimized using the proposed method to demonstrate its feasibility, with the optimal pumping rate, screen length and depth of each well computed. Furthermore, parametric studies were performed to investigate the effects of some key factors on the optimization results, such as the number of considered pumping wells, required drawdown, insertion ratio of the waterproof curtain, aquifer anisotropy coefficient, and prescribed well screen. The results show that optimal total pumping rate and screen length generally increase with increasing required drawdown and aquifer anisotropy coefficient, while they decrease with increasing well number and insertion ratio of the waterproof curtain. Adjusting screen length is more critical to the optimization results since lower screen depth is always preferred. Optimizing well screen is more essential for higher well number, insertion ratio of the waterproof curtain, and lower aquifer anisotropy coefficient.

Influence of Geology, Hydrogeology, and Climate on Ground Source Heat Pump Distribution in Slovenia and Selected European Countries

Shallow geothermal energy (SGE) is a renewable energy that could contribute to the decarbonatization of the heating and cooling sector. SGE is predominantly harnessed through ground source heat pump (GSHP) systems. The choice of which type of GSHP system depends on various factors. Understanding these factors is crucial for optimizing the efficiency of GSHP systems and fostering their implementation. In this paper, we have analysed the spatial distribution of GSHPs in Slovenia. We identified 1073 groundwater and 1122 ground-coupled heat pump systems with a total heat pump capacity of almost 30 MW. We quantitatively assessed the influence of geological, hydrogeological, and climate conditions on their spatial distribution. Using the χ2 test and information value method, we identified hydrogeological conditions as the most influential factor for the GSHP systems’ spatial distribution. We also performed the spatial analysis of geological and hydrogeological data in 22 European countries, including Slovenia. We collected the reported numbers of installed GSHP units in 2020 and were able to distinguish the shares of groundwater and ground-coupled heat pump systems for 12 of these countries. The analysis showed that ground-coupled heat pumps predominate in most countries, even if the natural conditions are favourable for groundwater heat pumps.

Simultaneous realization of high gain and low DMG of four-mode EDFA under bidirectional hybrid-mode pump.

We theoretically and experimentally verify that, the bidirectional hybrid-mode pumping scheme can address the optimization problem of trade-off between high gain and low differential modal gain (DMG) of four-mode erbium-doped fiber amplifier (4M-EDFA), in comparison with traditional both forward and backward hybrid-mode pumping scheme. It is noticed that, when the total pump power is fixed, the bidirectional hybrid-mode pumping scheme can not only achieve higher gain, but also suppress DMG due to different overlap integrals for the forward and backward pumping schemes. The bidirectional hybrid-mode pumped 4M-EDFA is developed with the forward pumping at LP02 mode and the backward pumping at LP21 mode, under a pump power ratio of 30%:70%. Thus, we can achieve an average gain of up to 21.16 dB and a low DMG of 0.43 dB at 1550 nm, and an average gain of up to 20.64 dB with a DMG of less than 1.6 dB over the C-band. In particular, the bidirectional hybrid-mode pumping scheme allows us to tailor the gain characteristics of the few-mode erbium-doped fiber amplifiers (FM-EDFAs), by adjusting the power ratio between forward and backward pumps.