Parallel Feed Research Articles

Hybrid and boosted structures of multi-effect mechanical vapor compression for enhanced water production

Retrofitting the multi-effect mechanical vapor compression (MEMVC) process for water desalination through hybridization with membrane distillation (MD) and/or employing vapor boosting mechanism is investigated in this work. The impact of using more than one mechanical compression, their respective locations and flow rates is investigated. Integration of parallel feed scheme of MEMVC with MD owned the maximum MD water production compared to the hybrid forward feed and parallel cross feed arrangements that can reach up to 54 % enhancement. However, the contribution of the MD production to the total production of the hybrid system does not exceed 17 %. Recycling the vapor of the last three effects to boost the first effect indicated a positive impact. The MEMVC with parallel feed can achieve 134 % water production enhancement with 26 % increase in the specific energy consumption over the nominal condition, i.e., when only the steam of the last effect is recycled to the first effect. Recycling the vapor of the penultimate effect to boost the second effect illustrated superior performance compared to that of boosting the first effect. It is found that the MEMVC with forward feed can attain 61 % improvement in water production with 14 % reduction in the specific energy consumption.

Energy and exergoeconomic analyses of parallel cross feed multi effect desalination system driven by twin-screw compressor with water injection

This work proposes the design of a parallel cross-feed multi-effect desalination system with a twin-screw compressor, incorporating water injection to enhance system performance. The improvement is achieved by injecting water during the compression process to increase the isentropic efficiency of compression. The mathematical model is solved using Engineering Equation Solver software, and the resulting mass and energy balance equations are validated against literature data. The system is analyzed and evaluated from energy, exergy, and exergy-economic perspectives, and compared with the performance of the conventional configuration in terms of specific power consumption, exergy efficiency, and cost of produced water. The impact of various operating conditions, such as the number of effects, steam temperature, compressor efficiency, and injection pressure, on specific power consumption, exergy efficiency, exergy destruction, and final product cost, is examined in this study. Additionally, factors like interest rate, plant life expectancy, and electricity cost are investigated for their effect on the final product cost. The study demonstrates that replacing the normal compressor with a twin-screw compressor result in more than a 15 % reduction in specific power consumption, approximately 4 % less exergy destruction (indicating higher exergy efficiency), and a 14 % lower unit cost of freshwater.

Complementary split resonant ring inspired wide-angle frequency-scanning patch array leaky-wave antenna with open-stopband suppression

In this paper, a wide-angle scanning and dual-linearly polarized leaky-wave antenna (LWA) is proposed based on symmetrical complementary split resonant ring (CSRR) feeding lines. The CSRR excites high-dispersed spoof surface plasmon polaritons (SSPPs) and is inspired to enlarge the scanning angle of the circular patch array antenna. The coupling between CSRR and circular patch determines the unit cell dispersion characteristics of LWA, and the coupling between CSRR and circular patch is controlled by designing their respective periods, p/b, to suppress the open-stopband and reduce the grating lobe, The value of p/b controls the frequency range of the open-stopband. Two parallel CSRR feeding lines are located on the bottom layer of the antenna and feed the array antenna of 11 circular patches above the feeding layer with both differential and common modes excitations. The two modes switch with 1-bit phase shifters on the two parallel feeding lines fed with a Wilkinson power splitter and electronically switch dual-linearly polarized radiations. The proposed scenario of the LWA prototype is validated through simulations and experiments. According to the measurements, horizontally polarized radiation achieves large beam scanning angle from −59.5° to +40° in the frequency range from 8 to 11 GHz with common mode excitation. And vertically polarized radiation scanning the main beam from −47° to +41° in the frequency range from 7.8 to 10.8 GHz with differential-mode excitation. The measured peak gains of the two polarizations are 14.4 dBi and 14.2 dBi, respectively, and the cross-polarization ratios are above 21 dB.

Research on Fault Identification of Hybrid Multi-Feed High-Voltage Direct Current System Based on Line Commutated Converter and Voltage Source Converter

With the rapid development of voltage source converter (VSC) and line commutated converter (LCC) technology and the relative concentration of power and load, the inverter station of the flexible DC system is fed into the same AC bus with the conventional DC rectifier station, and the high-voltage direct current (HVDC) parallel hybrid feed system is formed in structure. As the electrical distance between the converter stations is very close, when a fault occurs in the near area, the current on the AC wiring on the VSC side will fluctuate greatly, resulting in the misoperation of the AC wiring protection. For this reason, this paper proposes a fault identification method based on VSC/LCC hybrid multi-fed HVDC system, which discriminates the fault and outputs the protection signal according to the protection criterion, and logically judges the combination of the output protection signal to identify the fault type. The simulation results show that the method can identify all kinds of faults of hybrid multi-feed DC system and solve the problem of protection misoperation of the hybrid multi-feed DC system.

Design and test of an efficient seedling pick-up device with a combination of air jet ejection and mechanical action

Low degree of transplanting automation will affect production efficiency and planting quality in vegetable cultivation. A new seedling pick-up device was designed and constructed to reduce direct grasping damages to seedlings and improve transplanting efficiency. The pick-up device consists of an air jet loosening device, a flexible pick-up manipulator, a parallel feeding device, and a multi-axis motion control system. Its working principle is to use air jet ejection to assist in loosening of seedling roots from the tray cells, grasp their stems for extracting with the pick-up manipulator, and finally transfer them to the delivery device for feeding into the planting device as needed. The mechanical structure and working parameters of each component were designed, and the control system was constructed according to the working requirements of ejecting, extracting, transferring, and discharging operations. A prototype of the new pick-up device was constructed, and its performance evaluation was conducted using an orthogonal experimental design using cucumber, pepper and caluiflower as test objects. The results showed that the test object, the root lump's moisture content and the loosening way (either as a whole or individual loosening of seedlings) had significant effects on the success ratio in picking up seedlings. Overall, the success in picking up seedlings from the cell was found to be influenced by horticultural and mechanical factors. Under the optimal level group, the maximum success ratio for automatic picking up seedlings was up to 94.49% for pepper while that of cucumber and cauliflower recorded 90.75% and 92.62%, respectively. The seedling pick-up performance was satisfactory for efficient transplanting requirements.

A [formula omitted]45°dual-polarized co-channel patch antenna array for in-band full-duplex applications

A broadband stacked patch antenna array with high port isolation is presented for in-band full-duplex (IBFD) applications in this article. A co-channel feeding scheme is proposed to simultaneously excite two ports of the patch antenna to achieve ±45°dual polarization. An antenna system is then designed using a 2 × 2 stacked patch array, a parallel feeding network, and a hybrid coupler. The coupling between the Tx and Rx ports due to mismatch and coupling between the antenna elements is analysed in detail and shown to be eliminated completely. A demonstrator is fabricated and measured to endorse the accuracy of the proposed feeding scheme. The measured results show that the developed prototype can operate from 3.15 GHz to 4.0 GHz. The isolation level between Tx and Rx ports is higher than 45 dB within the operating band. The realized gains of two ports are higher than 10.5 dBi throughout the band of interest with the maximum gain of 13.9 dBi, which are congruent with the simulated ones.

Efficient Deweahter Mixture-of-Experts with Uncertainty-Aware Feature-Wise Linear Modulation

The Mixture-of-Experts (MoE) approach has demonstrated outstanding scalability in multi-task learning including low-level upstream tasks such as concurrent removal of multiple adverse weather effects. However, the conventional MoE architecture with parallel Feed Forward Network (FFN) experts leads to significant parameter and computational overheads that hinder its efficient deployment. In addition, the naive MoE linear router is suboptimal in assigning task-specific features to multiple experts which limits its further scalability. In this work, we propose an efficient MoE architecture with weight sharing across the experts. Inspired by the idea of linear feature modulation (FM), our architecture implicitly instantiates multiple experts via learnable activation modulations on a single shared expert block. The proposed Feature Modulated Expert (FME) serves as a building block for the novel Mixture-of-Feature-Modulation-Experts (MoFME) architecture, which can scale up the number of experts with low overhead. We further propose an Uncertainty-aware Router (UaR) to assign task-specific features to different FM modules with well-calibrated weights. This enables MoFME to effectively learn diverse expert functions for multiple tasks. The conducted experiments on the multi-deweather task show that our MoFME outperforms the state-of-the-art in the image restoration quality by 0.1-0.2 dB while saving more than 74% of parameters and 20% inference time over the conventional MoE counterpart. Experiments on the downstream segmentation and classification tasks further demonstrate the generalizability of MoFME to real open-world applications.

Eco-evolutionary dynamics of gut phageome in wild gibbons (Hoolock tianxing) with seasonal diet variations

It has been extensively studied that the gut microbiome provides animals flexibility to adapt to food variability. Yet, how gut phageome responds to diet variation of wild animals remains unexplored. Here, we analyze the eco-evolutionary dynamics of gut phageome in six wild gibbons (Hoolock tianxing) by collecting individually-resolved fresh fecal samples and parallel feeding behavior data for 15 consecutive months. Application of complementary viral and microbial metagenomics recovers 39,198 virulent and temperate phage genomes from the feces. Hierarchical cluster analyses show remarkable seasonal diet variations in gibbons. From high-fruit to high-leaf feeding period, the abundances of phage populations are seasonally fluctuated, especially driven by the increased abundance of virulent phages that kill the Lachnospiraceae hosts, and a decreased abundance of temperate phages that piggyback the Bacteroidaceae hosts. Functional profiling reveals an enrichment through horizontal gene transfers of toxin-antitoxin genes on temperate phage genomes in high-leaf season, potentially conferring benefits to their prokaryotic hosts. The phage-host ecological dynamics are driven by the coevolutionary processes which select for tail fiber and DNA primase genes on virulent and temperate phage genomes, respectively. Our results highlight complex phageome-microbiome interactions as a key feature of the gibbon gut microbial ecosystem responding to the seasonal diet.

Theoretical performance assessment of a multi-effect distillation system integrated with thermal vapour compression unit running on solar energy

Abstract Mathematical models can be successfully applied to predict the multi-effect distillation system integrated with thermal vapour compression unit (MED-TVC) performance under different operating conditions. In this work, a one-dimensional (1-D) mathematical model was developed to perform the theoretical analysis of a small-scale parallel feed MED-TVC desalination system driven by solar heat. A parametric study was conducted allowing the ejector motive steam temperature, first effect temperature, between effects temperature difference and ejector compression ratio to vary within an expectable range. The results showed that higher motive steam temperatures, had a positive impact on the water yield up to an optimal point. Any additional increase of driving steam temperature reduced water yield. Gain output ratio ($GOR$) was maximum at the highest considered motive temperature. It was found that the calculated specific heat transfer area does not depend on the motive temperature variation. Water yield, $GOR$ and specific heat transfer area decrease with the ejector compression ratio. The temperature difference between the evaporator effects had no effect on the water yield and $GOR$. It only decreases the specific heat transfer area. First effect temperature should be as low as possible with respect to operational constraints. Based on the parametric study, the optimal design operating conditions, corresponding to the maximum water yield is identified for a small-scale three-effect desalination system. The unit can produce up to 204 l/h drinking water with a gain output ratio of 8.6 and specific heat transfer area of 575 m2/kg/s using about 22 kW of solar heat.

Solar parallel feed multi effect distillation plant: An experimental study

This paper discusses about the parametric studies carried out on 10 m3/day capacity multi effect distillation desalination plant. In the present work studies were performed to determine the effect of process parameters on the production capacity of the MED plant. GOR of plant is around 3.6. Effect of solar irradiation on the evaporation rate in each effect is determined and presented with respect to time. Influence of the operating pressure and temperature on the performance of each effect is measured during the experiment and presented in the current work. Influence of steam input on the system performance is discussed. It was observed that increase in solar irradiation influences the steam production. Increase in the steam production rate influences GOR. Increase in the solar irradiation by 24% maximum on a typical day resulted in increase of evaporation rate by 20.6%, 17.3%, 15.7% and 12.3% corresponding to the effect 1, 2, 3 and 4 respectively. It was also observed that the production rate is found to be higher after the mid noon compared to the forenoon even though the solar irradiation is measured to be comparatively higher in forenoon than after mid noon.

MED-TVC Parallel Feed Water with Energy Recovery from Brine Preheating

MED-TVC Parallel Feed Water with Energy Recovery from Brine Preheating

A Review and Comparison of Transformer and Static Frequency Converter Traction Supply Architectures for AC Electrified Railways

Electrification of the U.K. railway network will play a critical role in achieving targets of net-zero CO2 emissions while providing major benefits to train operators, passengers, and industry. In the drive to make electrification a more cost-effective prospect, this paper intends to complete a comparison of the common feeding arrangements and the novel Static Frequency Converter for use in AC electrification using PSCAD EMTDC simulations. The findings illustrate the performance of two classic architectures and autotransformer feeding compared to a proposed classic SFC arrangement and provide recommendations for SFC implementation with separations between feeder stations of up to 60 kilometres using a parallel feeding arrangement, along with demonstrating SFCs exhibiting more robust performance in the event of faults.

Wideband millimeter-wave hybrid dielectric resonator antenna array with dual-slot feeding

ABSTRACTA hybrid dielectric resonator antenna (DRA) array is proposed for the wideband millimeter-wave communication. The radiator is composed with a pair of stacked dielectric resonators (DRs), which are H-shaped and Hexagon-shaped DRs, respectively. The dual-slots on the substrate integrated waveguide (SIW) cavity are utilized for higher mode generation in the DRA element. The antenna bandwidth is improved by the stacked DRs and dual-slot feeding. The structural characteristics and key parameters of feeding slots are discussed in detail. The DRA array fed with parallel power distribution feeding network is fabricated and measured to verify the reliability of the simulations, and the simulations and measurements have reasonable consistency. The impedance bandwidth is from 23.55 GHz to 27.28 GHz (14.7%), and the measured gain ranges from 13.1 dBi to 15.7 dBi. The radiation patterns are stable in the operation band. The proposed DRA array has a promising application prospect for 5 G communication system.

Energy and exergo-economic analysis of a parallel feed multi-effect system integrated with humidification–dehumidification system for brine recovery

Desalination technologies reject large amounts of brine with significant value back to sea. The concept of hybridization of different desalination technologies has proven that it can be effective in terms of reducing rejected brine and increasing the freshwater production rate as well as reducing the freshwater cost. In this work, brine recovery to improve water production through a simple modified configuration of integrating a multi-effect desalination (MED) system with humidification–dehumidification system (HDH). The rejected brine of the MED system is used as the feed for the HDH system without the need for preheating the rejected brine since it leaves the MED at a suitable temperature for HDH application. The study focuses on investigating the effect of different operating conditions on the increase in system freshwater production rate and recovery ratio as well as the exergetic efficiency. Parameters investigated include steam temperature, feed salinity, number of brine streams, cooling water flow rate, and ambient temperature. An exergo-economic analysis has also been conducted using the cost flow method to evaluate the freshwater production cost for the modified system. Results indicate that the integration of HDH can increase the water production rate by a maximum of 7.82% and produce fresh water at 2.08 $/m3 compared to 2.094 $/m3 when using the standalone system under the same conditions.

High-Gain Omnidirectional Horizontally Polarized Dipole Array for Sub-6 Base Station

A novel omnidirectional horizontally polarized (OHP) dipole antenna array with wide bandwidth and high gain is reported, which operates at Sub-6 band. A major improvement is the feeding method for omnidirectional radiation patterns which is inspired by classic turnstile antenna array. Six pairs of modified cross dipoles are positioned along a parallel feeding wire transmission line, and the dipole elements are placed in two orthogonal planes, with six dipole elements in each plane. The adjacent dipole elements on different planes are spaced by a quarter wavelength to produce an omnidirectional radiation pattern. The antenna array is simply machined with 1 mm diameter copper wire and fed by a coaxial structure at the center of the array. The max cross-section area is 3.17×0.5 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">λ</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> which can be limited in a cylinder. The measured and simulated results are in good agreement. The measured -10 dB impedance bandwidth covers 1.19 GHz from 3.83 to 5.02 GHz and the measured peak realized gain (RG) value is 7.44 dBi. The measured 1dB gain bandwidth of the proposed antenna is 1 GHz (22%) from 4 to 5 GHz. The advantages of high gain, broadband, omnidirectional radiation, and low cost make this antenna favorable in base station situations.

A cascaded modeling approach for comprehensive reaction state perception of a hydrometallurgical reactor

A hydrometallurgical reactor is the central production unit in a hydrometallurgy process. Due to the correlation between multiple parallel reactions and feeding condition fluctuations, modeling the outlet technical indicator alone is insufficient to express the highly informative reaction state comprehensively. This paper proposes a cascaded modeling approach for comprehensive reaction state perception of a hydrometallurgical reactor by considering the feeding conditions, operation modes, outlet technical indicators, and their relations. First, propose a perception model based on the information of two adjacent reactors for feeding condition perception. Second, develop an online operating mode perception model, combining dynamic feature extraction methods based on dynamic inner principal component analysis and mechanism knowledge. Finally, an outlet technical indicator perception model integrates mechanism and data features for multiple operation modes. The simulation results reveal that the proposed model can comprehensively describe the reaction state and guide on-site control.

Comprehensive performance of parallel feed MEE-MVC evaporation system

Abstract The mathematical model based on conservation of energy, mass and salinity is established to analyse the comprehensive performance of parallel feed multi-effect evaporation system with mechanical vapor compression (MEE-MVC) system. It is found that the efficiency of the MVC evaporation system gradually improves as the number of evaporator effect increases. However, the optimization trend of specific power consumption (SPC) and coefficient of performance (COP) are declining when the number of evaporator effect exceeds 3, which makes the marginal effect of the efforts made to improve the system gradually weakened. Then, the three-effect MVC evaporation system is taken as the main research subject to investigate comprehensive performance of the system. It was found that the SPC of the system increases with the increase of the total heat transfer temperature difference; on the other hand, the COP decreased significantly with the increase of the total heat transfer temperature difference. Furthermore, increasing the evaporation temperature in the last evaporator as well as compressor efficiency can optimize the energy efficiency of the system. In addition, the compressor efficiency has a greater influence on the SPC when the total heat transfer temperature difference is larger, whereas the compressor efficiency has a greater influence on the COP when the total heat transfer temperature difference is smaller.

Reaction-diffusion model applied to enhancing U-Net accuracy for semantic image segmentation

&lt;p style='text-indent:20px;'&gt;In our current paper we are introducing a new method to enhance semantic image segmentation accuracy of a U-Net neural network model by integrating it with a mathematical model based on reaction-diffusion equations.&lt;/p&gt;&lt;p style='text-indent:20px;'&gt;The methods currently used for semantic image segmentation, including U-Net neural networks, are processing images as blocks of pixels in which the boundaries, the colors and patterns are all mixed together as inputs to the transformations that take place inside the layers of the convolutional neural networks. In our method we are modifying the architecture of a U-Net network and introduce a new data input feed in parallel to the image feed that needs to be segmented. The new input feed is mathematically extracted from the input image and contains the edges (shape) information of the image to be processed. The new input feed it's used during the U-Net decoding phase in order to help shape more precisely the up-scaled output edges, thus leading to improved accuracy performance of the network.&lt;/p&gt;&lt;p style='text-indent:20px;'&gt;Introducing the parallel feed shows an improvement of accuracy metrics up to 4% (if compared to the U-Net model) and has a limited impact on computational resources consumed at training, because we are only adding a small number of new parameters to be calculated.&lt;/p&gt;

Novel Planar Ultra-Wideband Modular Antenna Array with Low Profile

A planar ultra-wideband modular antenna array with an ultra-low profile based on a tight coupling effect is proposed. The antenna array is composed of multi-layer printed circuit boards. Since its frequency operation can extend up to the grading lobe frequency, the number of T/R components for the antenna aperture is reduced to the greatest extent. Specifically, a horizontal “fin” structure is added on the parallel feeding lines, which assists in improving the impedance matching of the array. In order to break the bandwidth limitation of the low-frequency loop mode, a capacitive short-circuit probe is introduced to push the common-mode resonance point into the low-frequency band. Finally, subject to Active VSWR &lt; 3, the array can realize E-plane, H-plane, and D-plane ± 45° beam scan coverage across the 6:1 frequency band (3.48–20.97 GHz). A 128-element prototype was processed and tested to validate the design. This array not only has the advantages of low profile, modularity, easy assembly, and maintenance but also minimizes the number of T/R components and reduces the cost of phased array antennas.

Compact multiband bandpass filters based on parallel coupled split structure multimode resonators

In this letter, a novel sext-band bandpass filter (BPF) using two split-type multiple-mode resonators is proposed. The filter is composed of two sets of resonators which are respectively designed to realize Filter 1 with two passbands and Filter 2 with quad passbands. Then the two BPFs are combined by parallel coupling feed lines for sext-band responses, and each of the six centre frequencies in the proposed sext-band BPF is able to be controlled due to the design freedom. To validate the design and analysis, a prototype filter has been fabricated with six passbands centred at 1.88/2.59/3.48/5.26/5.82/6.75 GHz. The measured result of the fabricated filter agrees well with the simulation, which shows that the proposed structure is a good candidate for sext-band BPF designs and validates the proposed design flow well.