Dual Feeder Research Articles

Effective Strategies for Electron Beam Additive Manufacturing of Graded Metal Interfaces between Stainless Steel and Vanadium

This work examines the feasibility of joining two dissimilar metals, vanadium (V) and wrought Nitronic 40 stainless steel, through electron beam additive manufacturing (EBAM). Depositing V on Nitronic 40 led to mixed results with some builds exhibiting microcracking and other builds exhibiting severe cracking resulting in delamination. These build failures are thought to be caused by a large coefficient of thermal expansion (CTE) mismatch and solubility issues, demonstrating the challenges associated with this material combination. The large melting temperature discrepancy between Nitronic 40 and V was thought to exacerbate the issues with CTE mismatch and solubility. Four strategies could be employed by EBAM to mitigate the observed issues to successfully deposit V on Nitronic 40: (1) adjust wire feed speed, (2) use dual wire feeders, (3) use different wire feedstocks to control composition, and (4) create a transition layer known as buttering to accommodate CTE mismatch.

Dual modality feeders: a group of human milk feeders with unique practices and needs.

Dual modality feeding (DMF) - feeding human milk interchangeably from the breast and from a bottle - comes with unique practical, emotional and relational challenges, as well as support needs. Yet, there is little research that explores the experiences of individuals who use DMF in the Canadian context. The aim of this study is to explore the practices, challenges, reasons and enablers of DMF. Repeat, semi-structured one-on-one interviews were conducted at 8 weeks and 22 weeks postpartum. Interview transcripts were thematically analysed using a critical feminist lens. Nova Scotia, Canada. Ten DMF mothers. DMF practices were influenced by a mix of social and material circumstances, including breast-feeding challenges, the involvement of support persons, finances and access to lactation support. Individuals who predominantly fed at the breast expressed milk strategically to mitigate transitory breast-feeding challenges, for convenience under specific circumstances, and to share feeding responsibilities with other caregivers for personal and practical reasons. Individuals who mainly bottle-fed did so due to long-term breast-feeding challenges or a need to return to employment. Enablers of successful DMF were consistent between the two groups and included practical, personal and relational aspects. DMF is a unique practice compared to feeding human milk solely from the breast or bottle. Despite the potential growing prevalence of DMF, it is currently understudied and inadequately addressed in existing support programmes in Nova Scotia. Tailored programming and public messaging are needed to support DMF families.

Interline Unified Power Quality Conditioner for Enhancing Power Quality using FOFPID-based Interleaved CUK Converter

Electrical distribution systems face increased non-linear loads due to using power electronics for the converters. Due to these non-linear loads, the system exhibits PQ problems in the distributed feeders. To enhance PQ problems in the dual feeder, fractional order fuzzy proportional integral derivative controller (FOFPID) is introduced with interline unified power quality (IUPQC) conditioner. IUPQC conditioner includes a distribution static compensator (DSTATCOM), dynamic voltage restorer (DVR) and interleaved cuk converter (ICC). DSTATCOM and DVR are used for compensating the voltages and current in the dual feeders (feeder-1 and feeder-2). Also, ICC monitors the switching between the DSTATCOM and DVR compensators by providing proper power flow. Moreover, the FOFPID controller regulates an input supply from both feeders. The simulation is performed through MATLAB/Simulink platform, demonstrating the robustness of a proposed FOFPID with an IUPQC controller. The performance of a proposed controller is analyzed through two cases for both feeders. Furthermore, the total harmonic distortions (THD) are calculated for the feeder parameters. The proposed FOFPID with IUPQC controller also maintains stability in a dual feeder. Therefore, the entire response shows the functionality and feasibility of a proposed controller.

Our Experience of Eight Patients with Dural Arteriovenous Fistula's at Foramen Magnum with Respect to Presentation, Angioarchitecture, and Endovascular Treatment Outcomes.

Background Dural arteriovenous fistulas (DAVFs) around foramen magnum (FM) with peri medullary venous drainage, are uncommon and have wide spectrum of presentation. Literature about this lesion is sparse. We intent to analyze and report our experience with these cases with respect to presentation, evaluation, and endovascular treatment outcomes. Materials and Methods All the eight patients who were diagnosed with DAVFs at FM and treated with transarterial embolization using ethylene viny alcohol were included in this study. Clinical record sheets, radiological, and angiographic data of these patients were retrieved from our departmental database. Results Duration of symptoms ranged from 1 day to 3 years. Presentation with progressive ascending sensory symptoms and weakness ( N = 4), acute headache ( N = 2) acute quadriplegia ( N = 1), and right ear bruit ( N = 1) was seen. Exclusive feeders from occipital artery (OA) and vertebral artery (VA) were seen in two and four patients, respectively. Dual feeders from a combination of ascending pharyngeal artery and VA; from a combination of OA and VA were seen in one patient each. The exclusive venous drainage to spinal peri medullary veins ( N = 3), brain stem peri medullary veins ( N = 1), and both combined ( N = 4). Two patients had a draining vein aneurysm. Complete obliteration of fistula was achieved in all patients. Complete resolution of symptoms was seen in six patients; two patients had significant improvement. Conclusion The clinical presentation of dural AVF at foramen magnum is wide ranging and these lesions can be treated effectively and safely by transarterial embolization. Duration of symptoms strongly influences the final patient outcome.

Scimitar Syndrome in a Newborn

Introduction: Scimitar syndrome is a rare congenital condition that is usually presented in two major types, the infantile type as a severe condition with a poor outcome (median age: 2 months) and the adult type with a better condition and good outcome. It also has a wide spectrum of clinical presentations, from being asymptomatic in the adult type to cardiac and respiratory failure and pulmonary hypertension in the infantile type. Case Presentation: In this case report, we present a 43-day-old female case referred to Taleghani Children Hospital, Gorgan, Iran, with respiratory symptoms. In a physical examination, the case had a grade II/VI murmur, dextrocardia, and respiratory distress. In evaluations, the patient had severe stenosis proximal to the left common carotid artery after its origin. The heart and mediastinum were displaced to the right side, and the thoracic aorta was normal in size and orientation. bovine type of supra-aortic arch branches in the left-sided aortic arch, hypoplasia of the right upper lobe with severe hypoplasia of the right lower lobe were seen as well. There was sequestration adjacent to the right lower lobe with a dual feeder artery directly from the abdominal aorta and celiac branch and dual draining veins. Partial anomalous pulmonary venous connection was detected in the neck, and mediastinal computed tomography (CT) angiography with reconstructed views.. Bronchoscopy revealed right main bronchus hypoplasia and right lower lobe hypoplasia. Then, with the help of angiography, scimitar syndrome diagnosis was confirmed for the patient. Conclusions: Although scimitar syndrome is an uncommon condition, it has serious complications and poor outcomes in some patients. It is necessary to be aware of this rare congenital condition and use helpful methods, such as CT angiography and angiography, to confirm the diagnosis.

Practical quantum access network over a 10 Gbit/s Ethernet passive optical network.

Quantum key distribution (QKD) provides an information-theoretically secure method to share keys between legitimate users. To achieve large-scale deployment of QKD, it should be easily scalable and cost-effective. The infrastructure construction of quantum access network (QAN) expands network capacity and the integration between QKD and classical optical communications reduces the cost of channel. Here, we present a practical downstream QAN over a 10 Gbit/s Ethernet passive optical network (10G-EPON), which can support up to 64 users. In the full coexistence scheme using the single feeder fiber structure, the co-propagation of QAN and 10G-EPON signals with 9 dB attenuation is achieved over 21 km fiber, and the secure key rate for each of 16 users reaches 1.5 kbps. In the partial coexistence scheme using the dual feeder fiber structure, the combination of QAN and full-power 10G-EPON signals is achieved over 11 km with a network capacity of 64-user. The practical QAN over the 10G-EPON in our work implements an important step towards the achievement of large-scale QKD infrastructure.

Advanced Applications on Bilingual Document Analysis and Processing Systems

Today, rapid digitization requires efficient bilingual non-image and image document classification systems. Although many bilingual NLP and image-based systems provide solutions for real-world problems, they primarily focus on text extraction, identification, and recognition tasks with limited document types. This article discusses a journey of these systems and provides an overview of their methods, feature extraction techniques, document sets, classifiers, and accuracy for English-Hindi and other language pairs. The gaps found lead toward the idea of a generic and integrated bilingual English-Hindi document classification system, which classifies heterogeneous documents using a dual class feeder and two character corpora. Its non-image and image modules include pre- and post-processing stages and pre-and post-segmentation stages to classify documents into predefined classes. This article discusses many real-life applications on societal and commercial issues. The analytical results show important findings of existing and proposed systems.

Review of Solid State Transfer Switch on Requirements, Standards, Topologies, Control, and Switching Mechanisms: Issues and Challenges

Large-scale industrial loads, sensitive loads, and electrical power distribution systems suffer from power quality issues such as voltage interruptions, flickering, and sags which can cause a significant financial loss. The semiconductor based solid-state transfer switch (SSTS) can utilize the dual power feeders to protect the loads against these power disturbance issues. Conventional SSTS often requires more than quarter cycles to complete the transfer process because of load dependent commutation. Numerous researchers proposed the improved SSTS with impulse commutated circuit, which can reduce the transfer time and provide better ride-through capability against voltage sags. However, the SSTS specification depends on the application types and design procedure. Recently, hybrid SSTS has been introduced by the researchers to overcome all these issues. It has been investigated that not much papers are available in literature so far to aggregate all these issues. Therefore, towards the novel contribution of research, this review critically described the requirements, standards, and specifications of SSTS; control and switching mechanisms; and application of SSTS as single or hybrid topology, to give a comprehensive idea to the future researchers about the design of SSTS for a specific application. This paper also contributes to analyzing the key issues related to the SSTS applications, which can provide an easy control strategy and reduce the transfer time significantly. Overall, this research will strengthen the efforts of the researchers and industrialists to select, develop, and design the appropriate SSTS for a particular application.

Conveying Characteristics of Dual Pneumatic Feeder Used for Biomass Pyrolysis

A novel dual pneumatic feeder was developed to achieve constant and steady biomass conveying for pyrolysis. To facilitate the feedstock replenishment, an injection pipe was installed inside a pressure chamber to convey the feedstock. Another stream of gas entered the pressure chamber from the bottom to fluidize the particles. Experiments were performed to test the performance of the new feeder, and three injection pipes and gas distributors were used. Results showed that the feeding rate depended on both the injection and fluidizing gas velocities. The feeding rate decreased with the inner diameter (ID) of an injection pipe, due to its impact on gas velocity, while the effective injection distance had a negative effect within a certain range. The opening ratio of the gas distributors had a positive effect on the feeding rate. Then, a model was developed, based on the Ergun equation, to describe relationships between the feeding rate and the gas velocities. The classical equation was further reformed to establish the correlation between the solid mass flowrate and the construction parameters of the feeder. The developed model deviated from the measured values within ± 15%, which was considered capable to predict the feeder performances.

Understanding the cold spray deposition efficiencies of 316L/Fe mixed powders by performing splat tests onto as-polished coatings

Some of the current trends in cold spray include the production of metal-metal composite coatings; however, the deposition mechanisms of mixed powders are often vaguely understood. In this study, single component 316L stainless steel and Fe coatings, as well as composite 316L/Fe coatings, were deposited through cold spray and the deposition efficiencies (DE) were measured. The composite coatings featuring various feedstock fractions were produced using a dual powder feeder setup. Splat tests were then performed on the as-polished coatings to investigate the deposition behavior of each component powder on the previously deposited layers. Bond ratio (BR) was determined from the splat tests to correlate with DE. Results show that the 316L powder has a better DE than Fe; whereas the DE of 316L/Fe mixed powder increases with increasing the mixture feedstock Fe fraction. The BR was found to correlate well with the DE of both single component and mixed powders. For the individual deposition behavior of the component powder, the BR of 316L monotonically decreases on the composite coating with an increasing Fe fraction; while the BR of Fe plateaus at a relatively high value regardless of the composite coating composition, which results in the overall increase of mixture DE.

Late Quaternary Faunal Changes in Northeastern Patagonia (Argentina) according to a Dynamic Mosaic of Benthic Habitats: Taphonomic and Paleoecological Analyses of Mollusk Assemblages

The aim of this study was to describe and interpret the paleoenvironmental history of the San Matias Gulf (SMG) in northern Patagonia, Argentina, associated to possible biotic and abiotic changes occurred during the late Quaternary. In this regard a taphonomic (disarticulation, right/left valve ratio; fragmentation, abrasion, teeth preservation) and paleoecologic (alpha diversity, species abundance, life habit, substrate preference, feeding mode) analysis of A. purputata (the target species) and its accompanying faunal remains (the non-target species) in modern, Holocene and Pleistocene shell assemblages was performed. The general trend of the SMG throughout the late Quaternary is as a low energy environment, with varying intensity depending on the study area. Additionally, each study site contains different substrates showing patches of sand and rock, and this would also have determined the presence of certain species; in turn, the proportion of sandy and rocky patches may have changed over time which led to the development of different local paleocommunities. This gulf therefore presents a dynamic mosaic of environments over time, as evidenced by taphonomic and paleoecological analyses. Its waters would have been sufficiently rich in nutrients to allow the development of the filter fauna which have dominated the late Quaternary, especially A. purpurata. Dual feeder gastropods from hard substrates (Crepidula species) have increased in proportion through the Holocene. The variation in the composition of the fauna accompanying A. purpurata is due to certain physical, biological and even anthropic environmental conditions, which have changed through time. These changes coincided with the Last Glacial Maximum, the final configuration of the SMG and the Climatic Optimum of the Holocene.

Quantum secured gigabit optical access networks.

Optical access networks connect multiple endpoints to a common network node via shared fibre infrastructure. They will play a vital role to scale up the number of users in quantum key distribution (QKD) networks. However, the presence of power splitters in the commonly used passive network architecture makes successful transmission of weak quantum signals challenging. This is especially true if QKD and data signals are multiplexed in the passive network. The splitter introduces an imbalance between quantum signal and Raman noise, which can prevent the recovery of the quantum signal completely. Here we introduce a method to overcome this limitation and demonstrate coexistence of multi-user QKD and full power data traffic from a gigabit passive optical network (GPON) for the first time. The dual feeder implementation is compatible with standard GPON architectures and can support up to 128 users, highlighting that quantum protected GPON networks could be commonplace in the future.

Performance Analysis of Multi Converter Unified Power Quality Conditioner with Dual Feeder System using Fuzzy Logic Control

Many customers who require high reliable power, utilities provide dual feeds; i.e. service to a facility comes from two independent transmission lines. Maintaining power quality is an important issue in the transmission and sub transmission system. Unified Power Quality Conditioner is the optimal solution to ameliorate the quality of power. Many researchers analyzed the performance of UPQC with various control techniques. Recent advanced UPQC is the Multi Converter Unified Power Quality Conditioner (MCUPQC). Conventionally the MC-UPQC is controlled using the PI controller for DC link voltage control. This paper proposes Fuzzy Logic Controller (FLC) to enhance the performance of the MC-UPQC to improve the power quality in a multi bus with sub transmission system. In this article MC-UPQC is designed with two series and one shunt voltage-source converters (VSC). It is nominated to follow out in adjacent transmission lines to improve the quality of electric potential. In the proposed system, all converters are connected back to back on the dc side and share a common DC-link capacitor. It results in the transfer of power from one line to adjacent line to compensate for voltage sag/swell. Performance of MC-UPQC using the conventional PI controller and proposed FLC are compared. Harmonics produced by voltage distortion is also reduced within IEEE standards. The whole system is simulated and analyzed using MATLAB7.7/ Simulink.

Power budget analysis of dual/single feeder fiber WDMPON

This paper investigates how to reduce the cost of wavelength division multiplexing passive optical network (WDMPON) by comparing the transmission performance of bidirectional single feeder fiber and dual feeder fiber. Comparison is performed on the basis of power budgeting and cost of both arrangements. Simulation results using Optisystem show that the performance of a single feeder fiber is almost equivalent to that of a dual feeder fiber. Therefore, the single feeder fiber WDM-PON can efficiently replace the dual feeder fiber WDM-PON with the minimum deterioration in system performance and reduction in cost.

Impact of Rayleigh backscattering on single/dual feeder fiber WDM-PON architectures based on array waveguide gratings

The performance of colorless wavelength-division multiplexing passive optical network (WDMPON) systems suffers from transmission impairments due to Rayleigh backscattering (RB). A single feeder fiber colorless WDM-PON architecture was modeled, simulated and analyzed at 25 km distance that sustained the noise induced by RB. We analytically compared the performances between single feeder and dual feeder WDM-PON architectures based on array waveguide gratings (AWGs). For single feeder WDM-PON, the high extinction ratios in both return-to-zeros (RZ)-shaped differential phase shift keying (DPSK) downstream and intensity remodulated upstream data signals helped to increase the tolerance to the noise induced by RB. However, a cost effective colorless system in dual feeder WDM-PON architecture was achieved without any optical amplification and dispersion compensation, low power penalty. These results illustrate that single feeder fiber architecture was cost effective in terms of deployment having a power penalty, while dual feeder fiber had lower power penalty thereby with better performance. Simulation results show that downstream and upstream signals achieved error-free performance at 10-Gbps with negligible penalty and enhanced tolerance to the noise induced by RB over 25 km single mode fiber.

Waveguide Antenna Feeders With Integrated Reconfigurable Dual Circular Polarization

Waveguide antenna feeders with reconfigurable circular polarization sense are proposed in this paper. They can be switched between right and left hand circular polarization, without any mechanical rotation between the feeder and the antenna. Two types of feeders are presented. The polarizer works with a single switchable polarization for each state. The dual feeder can work with both polarizations at the same frequency band simultaneously, each one associated with a different rectangular waveguide port. The polarization sense is controlled by metallic posts that block or open the signal paths connecting the rectangular ports with a septum-orthomode polarizer. These posts are automated with piezo-motors integrated in the structure, leading to a very compact layout, reduced size, and practical for applications with diverse switching speed. The proof of concept and the automation are shown with experimental Ku-band prototypes.

Radiation efficiency improvement for dual-mode mobile phone using a slot on a ground plane

A dual-band mobile phone antenna with dual feeders is proposed to improve antenna radiation efficiency in the CDMA band of 824–894 MHz and the GSM band of 880–960 MHz. The proposed antenna consists of two planar inverted-F antennas and a common ground plane with a slot. The electric fields are more confined on each radiating element region at each band in this configuration. Measured results show that radiation efficiencies of the proposed antenna are improved by up to 20% compared to those of the antenna without a slot.

Quantum key distribution on a 10Gb/s WDM-PON

We present the first demonstration of quantum key distribution (QKD) on a multi-user wavelength division multiplexed passive optical network (WDM-PON) with simultaneous, bidirectional 10Gb/s classical channel transmission. The C-Band QKD system operates at a clock rate of 10GHz and employs differential phase shift keying (DPSK). A dual feeder fiber and band filtering scheme is used to suppress classical to quantum channel cross-talk generated by spontaneous Raman scattering, which would otherwise prevent secure key distribution. Quantum keys were distributed to 4 users with negligible Raman cross-talk penalties. The mean QBER value for 4 users was 3.5% with a mean raw key distribution rate of 1.3Mb/s, which decreased to 696kb/s after temporal windowing to reduce inter-symbol interference due to single photon detector timing jitter.

Design of an Impulse Commutation Bridge for the Solid-State Transfer Switch

Voltage sags have become a very critical power quality issue in recent years. In particular, in the high-tech industry parks of Taiwan, manufacturers can lose up to one million U.S. dollars for each voltage sag event. Some utility companies provide dual power feeders to these high-tech manufacturers to enhance power quality and reliability. The solid-state transfer switch (STS) based on thyristors can thus utilize the dual power feeders to protect sensitive loads against voltage sags. Conventional STS often requires more than a quarter cycle to complete the transfer process because its commutation is load dependent. An improved STS with impulse commutated circuit can greatly reduce the transfer time and provide better ride-through capability against voltage sags. In this paper, an impulse commutation bridge STS (ICBSTS) system is proposed to further simplify the forced-commutation circuitry. This paper also discusses the in-rush phenomenon of the transformer due to the line transfer. A flux estimator is developed with the ICBSTS system to reduce the in-rush current.

An In-Rush Current Suppression Technique for the Solid-State Transfer Switch System

More and more utility companies provide dual power feeders as a premier service of high power quality and reliability. To take advantage of this, the solid-state transfer switch (STS) is adopted to protect the sensitive load against the voltage sag. However, the fast transfer process may cause in-rush current on the load-side transformer due to the resulting DC-offset in its magnetic flux as the load-transfer is completed. The in-rush current can reach 2∼6 p.u. and it may trigger the over-current protections on the power feeder. This paper develops a flux estimation scheme and a thyristor gating scheme based on the impulse commutation bridge STS (ICBSTS) to minimize the DC-offset on the magnetic flux. By sensing the line voltages of both feeders, the flux estimator can predict the peak transient flux linkage at the moment of load-transfer and evaluate a suitable moment for the transfer to minimize the in-rush current. Laboratory test results are presented to validate the performance of the proposed system.