Single Pump Research Articles

Study on the performance characteristics of the substation PVASHP system based on TRNSYS

Taking the substation building as the research object, DeST software is used to simulate the annual building load of the case building, and the load results are connected to the TRNSYS software. At the same time, the G ENOPT software is used to optimize the solar inclination and azimuth, and the system simulation model of solar photovoltaic-air source heat pump is established and the data analysis is carried out. The results show that the peak cooling load of the substation building occurred on July 24th, The numerical value is the 49.28kW, The annual cumulative cooling load of the building is 20165.59 kWh; Based on Hooke Jeeves algorithm, the optimal inclination of photovoltaic panels is 44.18 and the optimal azimuth is 11.69; Typical days, The highest peak power of the air source heat pump appears at 1 a.m,Its peak power is 7.47 kW, The COP peak was 3.67; Within the typical week, Solar photovoltaic efficiency shows stable periodic changes, Peak aking around 12:00 noon, Its peak efficiency is 18.14%; There is a significant linear distribution relationship between the solar photovoltaic power generation capacity and the solar radiation, Its linear correlation coefficient was 0.85. Compared with the single air source heat pump system, the composite system saves 18.33% energy and has good application effect.

Dual coherent anti‐Stokes Raman scattering microscopy across the vibrational spectrum enabled by single pump optically synchronised oscillators and spectral focusing

AbstractCoherent anti‐Stokes Raman scattering microscopy probing two independently selectable vibrational frequencies across the vibrational spectrum is demonstrated. A one‐box femtosecond laser source provides three synchronised 100–200 fs pulses of 77 MHz repetition rate, one at a fixed wavelength of 1025 nm from an Yb oscillator and two independently tuneable ones, over 680–960 nm and 960–1300 nm, respectively, from two optically synchronised parametric oscillators. Combined with spectral focusing, the source allows addressing the fingerprint, cell silent and C–H stretch vibrational regions simultaneously, avoiding the motion artefacts seen in sequential imaging. We demonstrate the microscopy method on water/heavy water/oil emulsions, plastic beads and deuterated lipids inside cells.

Super-long gravity heat pipe geothermal space heating system: A practical case in Taiyuan, China

Using super-long gravity heat pipes (SLGHPs) to exploit deep-earth geothermal energy has indicated its technical superiority and viability; yet there is no practical application so far. The present work reports an SLGHP geothermal space heating system constructed in Taiyuan, China, which has two SLGHPs (2020 m and 2180 m long, respectively) in combination with a single heat pump. The two wells are located only ∼30 m apart, and the well-log temperature at 2000 m depth is around 63 °C for both. Temperatures measured by the optical fiber arranged along the SLGHP outer wall show remarkable uniformity, indicating the good performance of SLGHPs. Testing with the SLGHP system finds that the slightly longer SLGHP extracts 70 % more heat than the other one. Analyses reveal that the heat transfer in the geothermal formations surrounding the shorter SLGHP approximately follows the heat conduction regime while the convection of groundwater contributes less; the high yield of the slightly longer SLGHP is due to an interesting downhole heat transfer enhancement mechanism arising from the interlayer crossflow of groundwater. Further, a numerical model is developed to predict the SLGHP geothermal system's performance in 120-days’ operation. It is found that this system can output 1 MW of heat, sufficing space heating of ∼25,000 m2 buildings. The simulated 20-years’ operation indicates the thermal output degradation is 20.4 % for the shorter SLGHP, whereas it is only 6.8 % for the slightly longer SLGHP; the downhole groundwater crossflow lowers the SLGHP system degradation rate.

Energetic Potential of Parallel Operation of Two Heat Sources in a Dual-Source Heat Pump

Dual-source heat pumps can mitigate disadvantages of single source heat pumps: They have fewer geological requirements compared to ground-source heat pumps while having higher efficiencies compared to air-source heat pumps. Parallel operation of two heat sources can also make electric heaters for peak loads obsolete, leading to economic benefits in the operational costs. Parallel operation has not been analysed thoroughly at different evaporation temperature gradients. To address this gap in research, four possible interconnections of two heat sources were analysed using a refrigerant cycle simulation, two with similar and two with separate evaporation pressures. The energetic potential of each interconnection is evaluated and compared to single source operation with an air-source and a ground-source heat pump. The results showed that only the interconnections with separate evaporation pressure allowed significant reduction in evaporation power from the ground source. As expected, the efficiency – compared to single air-source operation – increased for all parallel interconnections but decreased compared to ground-source operation. Efficient peak load coverage with small ground-source collectors therefore requires a more complex interconnection of completely split evaporator branches at different evaporation pressures. While the efficiency and heating power compared to single ground-source operation decreased slightly (by 4% and 6%, respectively), the power load on the GSHX and ASHX reduced to about 54% and 66% compared to the corresponding single-source operation, respectively. This allows high efficiency at reduced GSHX size and ASHX noise emission. Additionally, this interconnection also allows increased flexibility for improved heat source management.

Application of Free Ball Check Valve Mixed Grouting Device

In recent years, due to the uneven water abundance of the aquifer and the complexity of the underground seepage field, the grouting reconstruction project of coal mining enterprises is more difficult. The previous method is to install a high-pressure ball valve before the grouting pipe connected to the grouting pump is connected to the mixing device, which can be manually adjusted when the number of grouting pumps needs to be changed. However, under certain pressure, the ordinary high-pressure ball valve often fails due to the influence of high-pressure mixed slurry, cement solidification and wear, and the number of grouting pumps cannot be increased or decreased in real time. In order to solve the problem that the mixing device of traditional grouting system is easy to fail by using ordinary high-pressure ball valve, the mixing device of free ball check valve was developed and applied in the process of treating the Ordovician limestone aquifer area on the floor of No.9 coal seam in Xipang Well. The practical results show that the pipeline can be automatically closed when a single grouting pump stops grouting, and there is no need to flush the grouting pipeline with a large amount of water, which can improve the grouting efficiency and quality, and the influence time of single hole section is reduced from 8.25h to 0.34h. The process performance can meet the requirements of efficient grouting.

Pumps: A Possible Tool to Promote More Equitable Lactation Outcomes.

Pregnant individuals and infants in the US are experiencing rising morbidity and mortality rates. Breastfeeding is a cost-effective intervention associated with a lower risk of health conditions driving dyadic morbidity and mortality, including cardiometabolic disease and sudden infant death. Pregnant individuals and infants from racial/ethnic subgroups facing the highest risk of mortality also have the lowest breastfeeding rates, likely reflective of generational socioeconomic marginalization and its impact on health outcomes. Promoting breastfeeding among groups with the lowest rates could improve the health of dyads with the greatest health risk and facilitate more equitable, person-centered lactation outcomes. Multiple barriers to lactation initiation and duration exist for families who have been socioeconomically marginalized by health and public systems. These include the lack of paid parental leave, increased access to subsidized human milk substitutes, and reduced access to professional and lay breastfeeding expertise. Breast pumps have the potential to mitigate these barriers, making breastfeeding more accessible to all interested dyads. In 2012, The Patient Protection and Affordable Care Act (ACA) greatly expanded access to pumps through the preventative services mandate, with a single pump now available to most US families. Despite their near ubiquitous use among lactating individuals, little research has been conducted on how and when to use pumps appropriately to optimize breastfeeding outcomes. There is a timely and critical need for policy, scholarship, and education around pump use given their widespread provision and potential to promote equity for those families facing the greatest barriers to achieving their personal breastfeeding goals.

Efficient two-stage modeling of heat plume interactions of geothermal heat pumps in shallow aquifers using convolutional neural networks

This paper presents an innovative approach to model the impact of geothermal heat pumps on groundwater temperature and the interaction of multiple heat plumes within the aquifer. The significance of this research lies in its applicability to real-time urban planning through a web application, where traditional simulation methods prove too time-consuming. Our methodology involves a two-stage neural network approach, leveraging convolutional neural networks (CNNs), trained on a simulated dataset constructed with realistic subsurface flow parameters extracted from borehole measurements in the Munich region.The research process is systematically structured into stages: the first stage rapidly predicts the general shape of a single heat pump’s plume in the absence of other influences. Building upon this, the second stage refines predictions by incorporating the interactions with neighboring heat plumes. Both stages employ CNNs, allowing for efficient training and evaluation. Experiments are conducted on dataset sizes of 100 and 1000 data points and on input parameters, focusing on a reduced dataset with data points of a spatial size of 256x16 pixels. The dataset is split into 70% training, 20% validation and 10% test data.Our results showcase the effectiveness of our approach, achieving a Root Mean Square Error (RMSE) of approximately 0.1 °C in both stages. This level of accuracy demonstrates the viability of our two-stage model in capturing the complex dynamics of GHWP interactions in shallow aquifers. The proposed methodology not only outperforms known analytical approximations but also significantly reduces computational costs of simulations, making it a promising tool for practical applications in city planning and beyond.

Optical reciprocity-nonreciprocity-amplification conversion based on degenerate four-wave mixing

Optical nonreciprocity plays an important role in optical communication and quantum networks. In this research, we propose and demonstrate a conversion scheme of magnetic-free dual-channel optical reciprocal amplification (RA) and nonreciprocal amplification (NRA) based on the multiple degenerate four-wave mixing (FWM) process in hot atoms. In our experiment, the dual-channel NRA works with the action of a single pump field based on the establishment of FWM in the same direction and breaking in the opposite direction. Based on stable ground-state Zeeman coherence, by introducing a counter-propagating pump field again, NRA can be changed to RA in the opposite direction of the two original amplified conjugate signals. Moreover, the frequencies of RA signals are very dependent on those of co-propagating pump fields. The experimental realization of NRA-RA conversion may have applications for multichannel angular momentum spatial multiplexing and quantum gate manipulation.

Comparative study of single pump all optical fiber amplifiers (POAs) with ultra wide band and high gain fiber optic parametric amplifiers in highly nonlinear fibers

Abstract This paper has clarified comparative study of single pump all optical fiber amplifiers with ultrawide band and high gain fiber optic parametric amplifiers in highly nonlinear fibers. Different amplifiers gain is demonstrated versus system distance for different light amplifiers in highly nonlinear fiber channel. As well as amplifier gain is clarified against system distance for different light amplifiers in DCF, DSF and NZDSF fiber channel. The mechanism of generation of single idler signal is studied based on single signal and pump signal. Moreover the mechanism of generation of single idler signal is analyzed and investigated clearly based on signal and two pump signals. Amplifier bandwidth is demonstrated against system distance for different fiber channel types in the presence of POA amplifiers based on 100 mW, 300 mW and 500 mW pumping power. The map of the signal losses is discussed and clarified versus wavelength band in the presence of all amplification techniques. Light signal per noise ratio and bit error rates are demonstrated against system distance for different fiber channel types in the presence of POA amplifiers based on 100 mW, 300 mW and 500 mW pumping power. POA is more suitable for the operation in HNLF fiber channel in compared to other proposed fiber communication channels. All optical amplifiers operation performance gain efficiency is compared together in different fiber channel media. The system can be employed with POAs for the fiber reach up to 100 km distance with a suitable amplifier gain and bandwidth. An important criteria for any amplifier is its gain and bandwidth for the compensation of the system loss and dispersion together. The optimum suitable pumping power is clarified for upgrade the system amplifier performance signature.

OSNR enhancement of Rayleigh-assisted Brillouin-Raman fiber laser via double pass configuration.

We propose and demonstrate a 10 GHz spacing multi-wavelength Brillouin-Raman fiber laser (MBRFL) with wide bandwidth and an outstanding optical signal-to-noise ratio (OSNR). This is achieved by utilizing loop mirror at one end of the laser cavity through a symmetrical bi-directional Raman pumping scheme. The setup is arranged in a double pass configuration by employing different lengths of dispersion compensating fibers (DCF). The attainment of MBRFL with outstanding performance necessitates the optimization of Raman pump power, Brillouin pump wavelength, and DCF length. By employing an 11 km DCF, when setting the Brillouin pump wavelength at 1531.4 nm, 504 Stoke lines are produced with a channel spacing of 0.08 nm. All the counted laser lines have less than a 1-dB peak amplitude variation and are spread across a 40.4 nm bandwidth that covers from 1531.4 to 1571.8 nm wavelength. In this case, the Raman pump power is fixed at 900 mW which results in average OSNR and Stokes peak amplitude level of 28 dB and -7 dBm respectively. To date, this is the simplest cavity design with the widest bandwidth and flattest spectrum together with outstanding OSNR attained in 10 GHz spacing multi-wavelength fiber lasers that incorporate a single low-power Raman pump unit.

Comparative study of low magnetic field effects in finger-finger and finger-split gate single electron pumps

Single Electron Pump (SEP) devices that can deliver single electrons at high frequencies are fabricated using two different gate geometries. The pump quantum dot (QD) can be defined either using two finger gates where the pump operates in what is known as the conventional pumping regime (CPR), or alternatively, the QD can be designed with the use of a single finger gate and split gate, where the pump operates in the long pumping regime (LPR). Here we investigate pump-maps produced in both the CPR and LPR under the effects of a low magnetic field (1 T to −1 T) and observe both the evolution of the pump-map and pump accuracy. Measurements were carried out in a cryogen free dilution refrigeration system with the use of a superconducting magnetic. Clear discrepancies between the behaviour of current in the different regimes can be seen indicating a fundamental difference in the operation of the pumps in the two different pumping regimes.

A novel data fusion based intelligent identification approach for working cycle stages of hydraulic excavators

Accurately identifying the stage of the excavator working cycle is the prerequisite to achieve the staged energy-saving control. However, current identification methods often overlook the influence of hydraulic system latency on identification results and depend on a single model, resulting in poor generalization performance of the identification approaches. Moreover, expert calibration system remains a necessary factor for improving identification accuracy. Aiming at these issues, a hybrid multi-scale feature extractor and a decision-level data fusion classifier approach (HMSFE-DFC) is proposed to identify the working cycle stages of excavator. The input signal employs mixed signals from the main pump pressure and the control current of the proportional solenoid valve to reduce the response delay caused by the single main pump pressure signal. A hybrid multi-scale feature extractor is constructed using a convolutional neural network temporal self-attention feature extraction mechanism and one-dimensional ResNet-50 architecture to extract multiscale features. To prevent overfitting, a decision-level data fusion classifier is used to fuse the decisions information of numerous classifiers. The accuracy of stage identification for 10 consecutive working cycles reaches 95.21%, which verifies its effectiveness.

Development of a bionic multi-chamber hydraulic cylinder for improving energy efficiency

Most hydraulic drive systems for robots are configured with one single pump and multiple cylinders, which suffers from low energy efficiency in the case of driving the variable loads. To solve the problem, this paper presents a multi-chamber hydraulic cylinder based on the bionic muscle drive mechanism. Firstly, the mechanical structure is designed, the mathematical models are derived, the mechanism of high energy efficiency is analyzed. Then, the simulation of load matching control is carried out, which shows the high energy efficiency improvement and the good position tracking. Finally, the multi-chamber hydraulic cylinder prototype is developed for experimental study, and output forces, output displacement, energy consumption, and friction characteristics are researched. The theoretical analysis and experimental research show that the bionic multi-chamber hydraulic cylinder can realize the power matching between the single power source and the variable loads in the hydraulic system, which provide a novel idea for the energy efficient hydraulic equipment.

A novel multicore Er/Yb co-doped microstructured optical fiber amplifier with peanut-shaped air holes cladding

Abstract The multicore fiber amplifier, as a key component in spatial division multiplexing (SDM) communication systems, presents higher technical difficulty compared to traditional multi-channel single core fiber amplifiers, which has sparked widespread attention. To achieve balance, efficiency, miniaturization, and cost-effectiveness in the performance of multi-core optical fiber amplifiers, we propose an innovative triple cladding 13-core Er/Yb co-doped microstructured fiber (13CEYDMOF). The proposed fiber features an outer cladding with peanut-shaped air holes, which enables uniform excitation of the 13 cores using a single multimode laser pump source within the inner cladding. This approach also prevents damage or aging of the fiber’s outer coating due to the pump laser. Furthermore, the design of Peanut-Shaped Air Holes effectively increases the numerical aperture (NA) of the inner cladding while reducing the outer diameter of the fiber, enhancing the fiber’s mechanical flexibility. To address the coupling difficulties caused by air holes, we bi-directionally pump the 13CEYDMOFA by utilizing a combined technique of the side winding and end pumping. The experimental results show that the 13CEYDMOFA can achieve an average gain of 23.8 dB, a noise figure (NF) of ∼4.6 dB, and an inter-core gain difference of less than 2 dB in the wavelength range of 1529–1565 nm. The in-line amplified transmission experiment demonstrates that the 13CEYDMOFA is well suited for the 13 spatial channels transmission. To the best of our knowledge, this is the first time to realize high performance telecommunication band amplification in a multicore microstructure fiber.

Cavitation diagnosis method of centrifugal pump based on characteristic frequency and kurtosis

Centrifugal pumps are important equipment in industrial production. At present, vibration signals are often used to diagnose cavitation in centrifugal pumps, but the vibration signals are easy to be disturbed and the fault characteristics are unstable to be detected. In this paper, a single stage centrifugal pump is taken as the study object, and the vibration signals of various parts of the centrifugal pump cavitation state are collected under different flow conditions. The short-time Fourier transform and one-third octave analysis are performed on the filtered signals, and the characteristic frequency of cavitation and the energy near the characteristic frequency with the development of cavitation are obtained. Based on vibration signals, the vibration root mean square (rms) and kurtosis values of different cavitation states are obtained. Flow state, kurtosis, and rms are used as input variables in the double-layer backpropagation neural network model to identify and classify the cavitation states of centrifugal pumps. The results show that the trained neural network model can accurately identify and classify the cavitation state of the centrifugal pump under the conditions of low flow rate, rated flow rate, and large flow rate, and the accuracy is more than 99.5%. This study provides a new technique for diagnosing cavitation in centrifugal pumps.

Optimal selection of parallel pumps running as turbines for energy harvesting in water transmission lines considering economic parameters

The need for energy is growing due to concerns about development and well-being, but the traditional methods of energy production harm people and the environment. This impact can be reduced by using renewable energy sources like hydropower. Since the cost of electromechanical equipment in small hydroelectric power plants accounts for a large percentage of the capital cost, applying the pump as turbine (PAT) is recommended. In this research, an effort has been made to select the optimal arrangement of PATs for a water transmission line without the need for control systems. The selection optimization process involves selecting the model of the pump as turbine and the number of turbines in parallel simultaneously. The optimization process relies on economic parameters, aiming to maximize the Net Present Value (NPV) of the power plant. In addition, the financial analysis of the project has been carried out. As a first step to achieve this objective, a database including single and double-suction pumps based on available pumps is needed. To cover a wider range of heads and flow rates, impeller trimming relationships for the pumps are considered. The Brute-Force algorithm has been used for the optimization process and two different objective functions (OF) have been investigated. First, it is based on economic optimization, and the NPV function is used as the OF; then, the Multi-Criteria Decision Making (MCDM) method is used as the second OF. The case study of this research is a water transmission line between two cities in Iran. A MATLAB code has been developed to perform all the steps of this study. The results demonstrate that by considering impeller trimming for pumps in the database and using NPV as OF, the number of pumps used for the power plant decreased from 12 to 6 and the capital cost decreased by about 10%. By implementing impeller trimming, the NPV and energy production of the PAT power plant are increased. Comparing the two desired objective functions leads to the recommended appropriate OF for applications. It is worth mentioning that the harvested energy from this water transmission line is about 9 GWh/year. The economic analysis results show that the PAT power plant payback period (PP) for this water transmission line is less than one year.

Transient ablation topography of a thin chromium film after ultrashort pulsed laser irradiation in the spallation and phase explosion regime

Time-resolved imaging pump–probe reflectometry is an established technique to characterize the dynamic processes occurring during the material ablation upon ultrashort pulsed laser irradiation. In the phase explosion regime, however, the presence of an expanding liquid–vapor mixture on top of the ablated material makes an unambiguous determination of the transient ablation topography almost impossible, especially when only front-side pump–probe reflectometry is used. To circumvent this limitation, the front-side reflectometry was complemented by rear-side reflectometry, where the probe radiation does not interact with the liquid–vapor mixture, and the underneath ablation kinetics of the material becomes observable. To interpret the measured front- and rear-side reflectances, an optical multilayer model of the ablation process was developed. Its applicability is demonstrated on a thin chromium film that was ablated by a single pump pulse. The optical model replicates the Newton rings measured during spallation and phase explosion very well, which allows the reconstruction of the transient ablation topography. The combination of the front- and rear-side reflectometry with modeling offers a valuable tool for studying the ablation processes in thin metal films, because it overcomes the challenges of the phase explosion regime, and thus enhances the understanding of material dynamics upon laser irradiation.

Sub-Nanosecond, High Peak Power Yb:YAG/Cr4+:YAG/YVO4 Passively Q-Switched Raman Microchip Laser with the Emission of Multiple Pulses

This paper demonstrates the capability of sub-nanosecond, high peak power Yb:YAG/Cr4+:YAG/YVO4 passively Q-switched Raman microchip lasers at 1134 nm operated in multiple pulses mode under quasi-continuous-wave (QCW) pumping. Total pulse energy for the Stokes laser was 1.8 mJ with a 4 mm YVO4 crystal and TOC = 16%. The corresponding pulse repetition rate reached 225 kHz within a single pumping pulse. By employing a compact plane-concave cavity and 5 mm YVO4 crystal, the single pulse energy for the Raman laser was further scaled up to 44 μJ. The corresponding peak power was 95 kW. A highest output pulse repetition rate of 87.8 kHz and shortest pulse duration of 464 ps were found for the Raman laser. The results indicate that the Raman microchip laser configuration under QCW LD pumping is a promising approach for developing high peak power, commercial and portable Raman lasers with a pulse duration of several hundred-picoseconds at a pulse repetition rate of hundred kilohertz.

A Comprehensive Study on Phase Sensitive Amplification and Stimulated Brillouin Scattering in Nonlinear Fibers with Longitudinally Varying Dispersion

Fiber optic parametric and phase sensitive amplifiers (PSA) are interesting for modern day communication technologies due to their low noise and high gain amplification properties with a potential for all optical signal processing and wide band operation. PSAs are typically employed in either a single pump or dual pump configuration. In this article we explore the utilities of both configurations, however considering a fiber with a longitudinally varying dispersion profile. For the single pump case, PSA operation at large pump-signal detunings, that arise due to the longitudinal dispersion variation, were studied numerically, and recipes of using the system as a wide band wavelength selective filter were laid out. For the dual-pump case, emphasis was laid on achieving a larger signal gain, by reducing stimulated Brillouin scattering (SBS) that prevents large pump power transport through the nonlinear fiber. First, the effects of dispersion variation on the gain of a dual pump PSA were studied analytically and numerically in order to optimize the dispersion variation profile, neglecting SBS processes. Then we independently studied the SBS dynamics of the system numerically. A sinusoidally dispersion oscillating fiber (DOF) was found to be an optimal candidate with respect to its PSA and SBS performances. To establish this claim, we also experimentally compared the performance of an available DOF over a standard highly nonlinear fiber (HNLF) that has a constant dispersion profile and established its utility for designing a high gain PSA system, thanks to the SBS mitigation due to the longitudinal dispersion variation of the fiber.

Mapping Light-Dressed Floquet Bands by Highly Nonlinear Optical Excitations and Valley Polarization.

Ultrafast nonlinear optical phenomena in solids have been attracting a great deal of interest as novel methodologies for the femtosecond spectroscopy of electron dynamics and control of the properties of materials. Here, we theoretically investigate strong-field nonlinear optical transitions in a prototypical two-dimensional material, hBN, and show that the k-resolved conduction band charge occupation patterns induced by an elliptically polarized laser can be understood in a multiphoton resonant picture, but, remarkably, only if using the Floquet light-dressed states instead of the undressed matter states. Our work demonstrates that Floquet dressing affects ultrafast charge dynamics and photoexcitation even from a single pump pulse and establishes a direct measurable signature for band dressing in nonlinear optical processes in solids, opening new paths for ultrafast spectroscopy and valley manipulation.