bluuebunny/crossref_metadata_2025 huggingface dataset:
In vacuostudies on plasma-enhanced atomic layer deposition of cobalt thin films
Authors: Reif Johanna , Knaut Martin , Killge Sebastian , Winkler Felix , Albert Matthias , Bartha Johann W.
Published: December 2019

Plasma-enhanced atomic layer deposition (PE-ALD) of cobalt (Co) using cyclopentadienylcobalt dicarbonyl [CpCo(CO)2] combined with hydrogen, nitrogen, ammonia, and argon based plasma gases was investigated. The utilized ALD tool was clustered to an ultrahigh vacuum analytic system for direct surface analyses including X-ray photoelectron spectroscopy (XPS). The combination with a nondestructive surface analysis system enabled a sample transfer without vacuum break and thereby a direct qualification and quantification of the chemical surface composition under quasi in situ conditions. The authors studied the influence of process parameters (e.g., pulse times, plasma power, and substrate temperature) on film compositions and film properties. The occurrence and prevention of sputtering effects due to ion bombardment at high plasma powers were discussed. Beyond those results, precise information about the impact of different plasma gas compositions on the resulting film properties was obtained. Cobalt films grown using a hydrogen/nitrogen (H2/N2) plasma as a coreactant showed a stable film composition (CoNx) with a high Co content of 75 at. %. Using scanning electron microscopy and four point probe measurements, a moderate electrical resistivity of about 56 μΩ cm was calculated for a 20 nm film. The high sensitivity of in vacuo XPS measurements allowed investigations of interface reactions for a single PE-ALD pulse as well as investigations of the initial film growth mechanisms. The nucleation of CoNx films during PE-ALD using H2/N2 plasma as a coreactant was investigated on several substrate materials by XPS. After the very first cycle of the PE-ALD process, no Co could be detected on all the investigated substrates. XPS revealed that the plasma pulse was needed to provide active binding sites for the adsorption reaction of precursor molecules due to the formation of Si-Nx or Si-NxOy surfaces. Therefore, the plasma pulse plays an important role in the PE-ALD process of Co on silicon surfaces. The early cycles were characterized by the onset of Co—O bonds. The homogeneous film body on all substrates consisted of Co-nitride compounds.
Suspended single-crystalline oxide structures on silicon through wet-etch techniques: Effects of oxygen vacancies and dislocations on etch rates
Authors: Lim Zheng Hui , Chrysler Matthew , Kumar Abinash , Mauthe Jacob P. , Kumah Divine P. , Richardson Chris , LeBeau James M. , Ngai Joseph H.
Published: December 2019

Wet-etch techniques to realize suspended microscale structures of single-crystalline SrTiO3 and BaTiO3 grown on Si are explored. The authors examine the effects of oxygen vacancies and dislocations on etch rates. Both oxygen vacancies and dislocations enhance etching, yielding rates that are sufficiently high to enable conventional photoresist to serve as a mask layer. Suspended bridge structures are realized by etching the underlying Si substrate using a potassium hydroxide solution. The ability to realize suspended microscale structures using wet-etch techniques that are compatible with standard semiconductor device processing opens a pathway to integrate multifunctional oxides in microelectromechanical systems.
Concurrent Validity of 2D and Inertial Goniometer Motion Assessment
Authors: Kraus Kornelius , Kraus Elisabeth , Gojanovic Boris , Fourchet Francois
Published: December 2019

Context: The validity and reliability of manual goniometry is highly dependent on the examiner’s expertise. Technological advances can overcome these problems to some extent. Inertial goniometry, for instance, could bridge the gap between 2D and manual goniometry, but its validity remains to be studied. Participants: 40 healthy individuals (mean ± SD: 31 men, age = 23.9 ± 4.1 years, 184 ± 6 cm, 80.7 ± 10.0 kg; 9 women, age = 23.6 ± 3.6 years, 170 ± 4 cm, 60.6 ± 5.1 kg). Measurements: 2D and inertial goniometry by mobee med™ were used to measure active and passive single straight-leg raise mobility performance. Intracorrelation coefficients (ICCs) and typical error of the estimate (TEE) inform the reliability and quality of the measurement by the rater. Results: The relationship of the inertial goniometry for active and passive mobility of the single straight-leg raise was practically perfect (r = .95–.98). Based on the Bland-Altman plots, the means of the difference between the 2D and inertial based goniometry were small (2–3°). Conclusion: Due to its high concurrent validity, ease of use, and efficiency with regard to time and personnel requirements, this inertial goniometer device is an effective and efficient approach to measuring range of motion. However, additional validity and reliability studies should investigate joints with more degrees of freedom.
A Comprehensive Nonoperative Rehabilitation Program Including Blood Flow Restriction for a Talus Fracture in a Professional Hockey Player: A Case Report
Authors: Di Lemme Stephanie , Sanderson Jon , Celebrini Richard G. , Dover Geoffrey C.
Published: December 2019

A 22-year-old male professional hockey player sustained a nondisplaced talus fracture. We present a comprehensive nonsurgical rehabilitation that includes blood flow restriction (BFR) training. Pain and function measures improved throughout the rehabilitation. Lower limb circumference did not change postinjury. The patient returned to play in less than 7 weeks, while current talar fracture management protocols indicate surgical fixation and 6 weeks of immobilization. BFR training may be useful in injury rehabilitation, negating muscle atrophy and increasing muscle strength while allowing the patient to exercise at relatively low loads. This is the first case of BFR training implemented in early fracture rehabilitation of an athlete.
“Suspended Above, and in Action”: Think Aloud as a Reflective Practice Tool
Authors: Stephenson James , Cronin Colum , Whitehead Amy E.
Published: December 2019

Think Aloud (TA) involves an individual verbalising his or her thoughts throughout the duration of a task. A case study approach examined the experiences of one football coach (Dave) as he engaged in four coaching sessions using TA. Dave completed four reflective diaries, supported by an overall narrative account, TA transcriptions, and two interviews. The aim of the case study was to gain a deeper understanding of Dave’s experiences of using TA in his context. Interpretative phenomenological analysis was utilised and revealed a superordinate theme of “suspended above himself” and actively engaging in the coaching session, which reflects the essence of TA for Dave. This metaphor captures the view that the TA process enabled Dave to move between analysing his own performance as if suspended above himself, and engaging in the action of the coaching session. Five subordinate themes were also generated: improved self-awareness, pedagogy, communication skills, feelings of apprehension, and distraction. These findings provide a rich description of the experience of TA and a novel glimpse into the potential pitfalls associated with TA that will inform coach educators. A further significant contribution is provided by highlighting relevant theoretical considerations that will inform future studies.
Why colorectal screening fails to achieve the uptake rates of breast and cervical cancer screening: a comparative qualitative study
Authors: Kotzur Marie , McCowan Colin , Macdonald Sara , Wyke Sally , Gatting Lauren , Campbell Christine , Weller David , Crighton Emilia , Steele Robert J C , Robb Kathryn A
Published: December 2019

Background

In Scotland, the uptake of clinic-based breast (72%) and cervical (77%) screening is higher than home-based colorectal screening (~60%). To inform new approaches to increase uptake of colorectal screening, we compared the perceptions of colorectal screening among women with different screening histories.

Methods

We purposively sampled women with different screening histories to invite to semistructured interviews: (1) participated in all; (2) participated in breast and cervical but not colorectal (‘colorectal-specific non-participants’); (3) participated in none. To identify the sample we linked the data for all women eligible for all three screening programmes in Glasgow, Scotland (aged 51–64 years; n=68 324). Interviews covered perceptions of cancer, screening and screening decisions. Framework method was used for analysis.

Results

Of the 2924 women invited, 86 expressed an interest, and 59 were interviewed. The three groups’ perceptions differed, with the colorectal-specific non-participants expressing that: (1) treatment for colorectal cancer is more severe than for breast or cervical cancer; (2) colorectal symptoms are easier to self-detect than breast or cervical symptoms; (3) they worried about completing the test incorrectly; and (4) the colorectal test could be more easily delayed or forgotten than breast or cervical screening.

Conclusion

Our comparative approach suggested targets for future interventions to increase colorectal screening uptake including: (1) reducing fear of colorectal cancer treatments; (2) increasing awareness that screening is for the asymptomatic; (3) increasing confidence to self-complete the test; and (4) providing a suggested deadline and/or additional reminders.
Modified fermion tunneling radiation of Demianski–Newman black hole at higher energy scales
Authors: Luo Z. , Lan X. G.
Published: December 2019

It is suggested that the dispersion relation might be corrected at higher energy scales and lead to the deformed Hamilton–Jacobi equation. In this paper, we use the correction to investigate the fermion tunneling radiation for Demianski–Newman black hole spacetime, and the result shows that the corresponding Hawking temperature and the black hole entropy are related to the angular parameters of the black hole coordinates.
PROPERTIES OF AUTOSEMANTIC WORD NETWORKS IN UKRAINIAN TEXTS
Authors: BUK SOLOMIJA , KRYNYTSKYI YURI , ROVENCHAK ANDRIJ
Published: December 2019

We present results of network analysis of Ukrainian texts. Autosemantic (meaningful) words are considered as network vertices connected with links when belonging to one sentence. Subnetworks corresponding to specific parts of speech (verbs, nouns, adjectives, etc.) are also built. The obtained networks are small-world and scale-free. To make comparisons, random texts with parameters corresponding to real texts are generated using several approaches. Various parameters of networks are calculated, including transitivity, betweenness, degree centralization, mean distance, network diameter, exponents of degree distribution, etc. Comparison of network parameters of real and generated texts shows that borders between them are quite fuzzy.
MINIMAL EDGE CONTROLLABILITY OF DIRECTED NETWORKS
Authors: XIANG LINYING , CHEN GUANRONG
Published: December 2019

Minimal edge controllability of directed networks is investigated in this paper. A new edge dynamics model is first introduced with two nonzero parameters describing the linear relationship between the node states and the edge states. Three different digraphs as skeleton structures for minimal edge controllability are analyzed. The conditions ensuring both node controllability and edge controllability for these three digraphs are presented, respectively. It is found that cycles in these networks play an important role in edge controllability. The notion of minimal edge controllability is then extended to signed digraphs. It is shown that the minimal edge controllability of a signed cycle depends on the number of edges with negative weights, regardless of the placement of the negative weights on the edges. Some examples are presented for illustration and verification.
Towards Adaptive Ontology Visualization — Predicting User Success from Behavioral Data
Authors: Fu Bo , Steichen Ben , Zhang Wenlu
Published: December 2019

Ontology visualization plays an important role in human data interaction by offering clarity and insight for complex structured datasets. Recent usability studies of ontology visualization techniques have added to our understanding of desired features when assisting users in the interactive process. However, user behavioral data such as eye gaze and event logs have largely been used as indirect evidence to explain why a user may have carried out certain tasks in a controlled environment, as opposed to direct input that informs the underlying visualization system. Although findings from usability studies have contributed to the refinement of ontology visualizations as a whole, the visualization techniques themselves remain a one-size-fits-all approach, where all users are presented with the same visualizations and interactive features. By contrast, this paper investigates the feasibility of using behavioral data, such as user gaze and event logs, as real-time indicators of how appropriate or effective a given visualization may be for a specific user at a moment in time, which in turn may be used to inform the adaptation of the visualization to the user on the fly. To this end, we apply established predictive modeling techniques in Machine Learning to predict user success using gaze data and event logs. We present a detailed analysis from a controlled experiment and demonstrate such predictions are not only feasible, but can also be significantly better than a baseline classifier during visualization usage. These predictions can then be used to drive the adaptations of visual systems in providing ad hoc visualizations on a per user basis, which in turn may increase individual user success and performance. Furthermore, we demonstrate the prediction performance using several different feature sets, and report on the results generated from several notable classifiers, where a decision tree-based learning model using a boosting algorithm produced the best overall results.
Integrated Bioinformatics Analysis Identifies Hub Genes Associated with the Pathogenesis and Prognosis of Esophageal Squamous Cell Carcinoma
Authors: Zhang Hui , Zhong Jianing , Tu Youbing , Liu Benquan , Chen Zhibo , Luo Yunchen , Tang Yaping , Xiao Fei , Zhong Jincai
Published: December 2019

Esophageal squamous cell carcinoma (ESCC) accounts for over 90% of all esophageal tumors. However, the molecular mechanism underlying ESCC development and prognosis remains unclear, and there are still no effective molecular biomarkers for diagnosing or predicting the clinical outcome of patients with ESCC. Here, using bioinformatics analyses, we attempted to identify potential biomarkers and therapeutic targets for ESCC. Differentially expressed genes (DEGs) between ESCC and normal esophageal tissue samples were obtained through comprehensive analysis of three publicly available gene expression profile datasets from the Gene Expression Omnibus database. The biological roles of the DEGs were identified by Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. Moreover, the Cytoscape 3.7.1 platform and subsidiary tools such as Molecular Complex Detection (MCODE) and CytoHubba were used to visualize the protein-protein interaction (PPI) network of the DEGs and identify hub genes. A total of 345 DEGs were identified between normal esophageal and ESCC samples, which were enriched in the KEGG pathways of the cell cycle, endocytosis, pancreatic secretion, and fatty acid metabolism. Two of the highest scoring models were selected from the PPI network using Molecular Complex Detection. Moreover, CytoHubba revealed 21 hub genes with a valuable influence on the progression of ESCC in these patients. Among these, the high expression levels of five genes—SPP1, SPARC, BGN, POSTN, and COL1A2—were associated with poor disease-free survival of ESCC patients, as indicated by survival analysis. Taken together, we identified that elevated expression of five hub genes, including SPP1, is associated with poor prognosis in ESCC patients, which may serve as potential prognostic biomarkers or therapeutic target for ESCC.
Costus afer: A Systematic Review of Evidence-Based Data in support of Its Medicinal Relevance
Authors: Boison Daniel , Adinortey Cynthia Ayefoumi , Babanyinah Godwin Kweku , Quasie Olga , Agbeko Rosemary , Wiabo-Asabil Gilbert Kofi , Adinortey Michael Buenor
Published: December 2019

Costus afer (C. afer) is a plant commonly known as ginger lily, spiral ginger, or bush cane. It is reportedly used in traditional medicine practice (TMP) to treat and manage many ailments including diabetes mellitus, stomach ache, arthritis, inflammation, and gout. These purported ethnomedicinal uses have triggered many research studies on the plant to amass scientific evidence. However, these research reports are scattered, and thus, this systematic review seeks to provide a comprehensive update on it covering its traditional uses, phytochemical and nutritional constituents, pharmacological activities, and toxicological effects. An online search was done using search engines such as Google Scholar, PubMed, and ScienceDirect from the period 1970 to 2019. The online search included the use of keywords, “Costus afer Ker-Gawl” or “Costus afer.” The search revealed that the stem and leaves of the plant contain substantial amounts of micronutrients and macronutrients. The leaves, stem, rhizomes, and roots of C. afer contain several steroidal sapogenins, aferosides, dioscin, and paryphyllin C and flavonoid glycoside kaempferol-3-O-α-L-rhamnopyranoside. Experimental studies on various parts of the plant showed bioactivities such as antihyperglycemic, hepatocellular protection, cardioprotection, nephroprotection, testicular protection, CNS depressant, analgesic, antiarthritis, antibacterial, and antioxidant. Based on these evident data, it is concluded that the plant could be used as an alternative and complementary therapy for many oxidative stress-related diseases, provided further scientific studies on the toxicological and pharmacological aspects are carried out.
Hybrid DE-EM Algorithm for Gaussian Mixture Model-Based Wireless Channel Multipath Clustering
Authors: Li Yupeng , Zhang Jianhua , He Ruisi , Tian Lei , Wei Hewen
Published: December 2019

In this paper, the Gaussian mixture model (GMM) is introduced to the channel multipath clustering. In the GMM field, the expectation-maximization (EM) algorithm is usually utilized to estimate the model parameters. However, the EM widely converges into local optimization. To address this issue, a hybrid differential evolution (DE) and EM (DE-EM) algorithms are proposed in this paper. To be specific, the DE is employed to initialize the GMM parameters. Then, the parameters are estimated with the EM algorithm. Thanks to the global searching ability of DE, the proposed hybrid DE-EM algorithm is more likely to obtain the global optimization. Simulations demonstrate that our proposed DE-EM clustering algorithm can significantly improve the clustering performance.
Wooden Penetrating Pelvic Trauma Passing the Foramen Ischiadicum
Authors: Abel Benedikt Ruben , Meyer Heinz-Lothar , Müller Roman , Henze Katharina , Dudda Marcel , Kauther Max Daniel
Published: December 2019

We describe the case of a 45-year-old woman who suffered an impalement injury of the pelvis with penetration of the sciatic foramen by a wooden foreign body. Following a single operation, the injury healed without complications or infection. We have taken this as an opportunity to describe the case and our standard procedure in more detail.
Ipilimumab- and Nivolumab-Induced Colitis Causing Severe Hypokalemia and QTc Prolongation
Authors: Anson David , Norton Joseph , Chaucer Benjamin , Bansal Saurabh
Published: December 2019

Immune-mediated colitis is an uncommon but well-documented adverse event in patients receiving nivolumab or ipilimumab therapy. In this report, we present a 69-year-old man who developed severe hypokalemia and colitis with significant corrected Q-T segment (QTc) prolongation as a result of combination nivolumab-ipilimumab immunotherapy for clear cell renal cell carcinoma.
All-Trans Retinoic Acid Enhances Bacterial Flagellin-Stimulated Proinflammatory Responses in Human Monocyte THP-1 Cells by Upregulating CD14
Authors: Hoang Thi Xoan , Jung Jong Hyeok , Kim Jae Young
Published: December 2019

All-trans retinoic acid (ATRA), an active form of vitamin A, exerts immunomodulatory functions. In this study, we examined the immune potentiating effect of ATRA on bacterial flagellin-induced NF-κB activation and proinflammatory cytokine production in human monocytic cell line THP-1. ATRA treatment significantly enhanced the flagellin-induced NF-κB/AP-1 activity in THP-1 via the RAR/RXR pathway. Similarly, ATRA enhanced the expression and production of TNF-αand IL-1βin THP-1 cells upon flagellin challenge. The cell surface expression of toll-like receptor 5 (TLR5), which is the receptor for bacterial flagellin, was significantly reduced by ATRA in a concentration- and time-dependent manner. To determine the mechanisms underlying the ATRA-enhanced immune response against bacterial flagellin despite the reduced cell surface expression of TLR5 in ATRA-treated THP-1, we examined the cell surface expression of CD14, which has been proposed to be a TLR co-receptor that enhances the response to microbial components. The cell surface expression of CD14 was significantly enhanced by ATRA treatment, especially in the presence of flagellin. Anti-CD14 antibody treatment prior to ATRA and flagellin treatments completely abolished ATRA-enhanced TNF-αand IL-1βproduction. Our results suggest that ATRA enhances flagellin-stimulated proinflammatory responses in human monocyte THP-1 cells by upregulating CD14 in a RAR/RXR-dependent manner.
Emphysematous Pyelonephritis Caused by a Giant Fecaloma
Authors: Abi Abdallah Mikael , Raad Nehme , Yarak Naim , Noujeim Jean Paul , Noujeim Antoine
Published: December 2019

Emphysematous pyelonephritis (EPN) is a gas-producing necrotizing bacterial infection that involves the renal parenchyma and perirenal tissue. It is a life-threatening condition that requires a high index of suspicion, an early diagnosis and an aggressive treatment. Rapid progression to septic shock may occur. We report, to the best of our knowledge, the first case of obstructive EPN caused by a giant fecaloma. The patient was successfully treated with percutaneous drainage and broad-spectrum antibiotics, in addition to fecaloma evacuation using fleet enemas and oral laxatives. This shows how fecal impaction, a common pathology in routine clinical practice, can cause some serious complications if left untreated, including extrinsic ureteral compression.
Human Adipose-Derived Hydrogel Characterization Based on In Vitro ASC Biocompatibility and Differentiation
Authors: Mohiuddin Omair A. , O’Donnell Benjamen T. , Poche J. Nicholas , Iftikhar Rida , Wise Rachel M. , Motherwell Jessica M. , Campbell Brett , Savkovic Suzana D. , Bunnell Bruce A. , Hayes Daniel J. , Gimble Jeffrey M.
Published: December 2019

Hydrogels serve as three-dimensional scaffolds whose composition can be customized to allow attachment and proliferation of several different cell types. Extracellular matrix-derived hydrogels are considered close replicates of the tissue microenvironment. They can serve as scaffolds for in vitro tissue engineering and are a useful tool to study cell-scaffold interaction. The aim of the present study was to analyze the effect of adipose-derived stromal/stem cells (ASCs) and decellularized adipose tissue-derived (DAT) hydrogel interaction on ASC morphology, proliferation, differentiation, and DAT hydrogel microstructure. First, the ASCs were characterized using flow cytometry, adipogenic/osteogenic differentiation, colony-forming unit fibroblast assay and doubling time. The viability and proliferation assays showed that ASCs seeded in DAT hydrogel at different concentrations and cultured for 21 days remained viable and displayed proliferation. ASCs were seeded on DAT hydrogel and cultured in stromal, adipogenic, or osteogenic media for 14 or 28 days. The analysis of adipogenic differentiation demonstrated the upregulation of adipogenic marker genes and accumulation of oil droplets in the cells. Osteogenic differentiation demonstrated the upregulation of osteogenic marker genes and mineral deposition in the DAT hydrogel. The analysis of DAT hydrogel fiber metrics revealed that ASC seeding, and differentiation altered both the diameter and arrangement of fibers in the matrix. Matrix metalloproteinase-2 (MMP-2) activity was assessed to determine the possible mechanism for DAT hydrogel remodeling. MMP-2 activity was observed in all ASC seeded samples, with the osteogenic samples displaying the highest MMP-2 activity. These findings indicate that DAT hydrogel is a cytocompatible scaffold that supports the adipogenic and osteogenic differentiation of ASCs. Furthermore, the attachment of ASCs and differentiation along adipogenic and osteogenic lineages remodels the microstructure of DAT hydrogel.
Reduced-order observer for real-time implementation speed sensorless control of induction using RT-LAB software
Authors: Bechar Mansour , Hazzab Abdeldjebar , Habbab Mohamed , Sicard Pierre
Published: December 2019

In this paper, Reduced-Order Observer For Real-Time Implementation Speed Sensorless Control of Induction Using RT-LAB Softwareis presented. Speed estimation is performed through a reduced-order observer. The stability of the proposed observer is proved based on Lyapunov’s theorem. The model is initially built offline using Matlab/Simulink and implemented in real-time environment using RT-LAB package and an OP5600 digital simulator. RT-LAB configuration has two main subsystems master and console subsystems. These two subsystems were coordinated to achieve the real-time simulation. In order to verify the feasibility and effectiveness of proposed method, experimental results are presented over a wide speed range, including zero speed.
Performance evaluation of multi-phase permanent magnet synchronous motor based on different winding configurations and magnetization patterns
Authors: Rezal M. , Ishak D.
Published: December 2019

Permanent magnet synchronous motor (PMSM) is the most reliable and efficient machine that widely used in robotics and automation, industrial applications, electric vehicles, home appliances, aircraft and aerospace technology due to its high efficiency, good dynamic performance and high torque density. In this paper, the influence of various types of winding configuration and different magnetization patterns in the performance of a five-phase PMSM is investigated. Three types of magnetization patterns such as radial magnetization (RM), parallel magnetization (PaM), and multi-segmented Halbach magnetization (SH) are applied to the five-phase 10-slot/4-pole PMSM during open-circuit and on-load conditions. A 2D finite element method (FEM) is intensively used in this investigation to model and predict the electromagnetic characteristics and performance of the PMSM. The detailed results from the finite-element analysis (FEA) on the cogging torque, induced back-emf, airgap flux density and electromagnetic torque are analysed. The induced back-emf of the machine is computed further into its harmonic distortions. Additionally, the skewing method for minimization of cogging torque of PMSM is proposed. From the results, it is observed that the five-phase, 10-slot/4-pole PMSM with double layer distributed winding and parallel magnetization gives the best machine performance.
Power flow variation based on extreme learning machine algorithm in power system
Authors: Imen Labed , Djamel Labed
Published: December 2019

The main focus of this paper is a study that empowers us to understand how the temperature variation affects the transmission line resistance and as a result the power flow analysis with a specific end goal to assess losses in the electrical network. The paper is composed of two sections; the first part is a power flow study under normal conditions utilizing the neural network approach while the second investigated extreme learning machine algorithm efficiency and exactitude. Extreme learning machine algorithm has been used to settle several complications in power system: load forecasting, fault diagnosis, economic dispatch, security, transient stability; Thus, we proposed to study this technique to figure out this sort of complex issue.
The study was conducted for IEEE 30 bus test system. The simulation results are exposed and analyzed in detail at the end of this paper.
PV integrated series active filter for sag voltage and harmonic compensation
Authors: Meftouhi Abdelmalek , Abdelkhalek Othmane , Allali Ahmed , Abdelkader Abdallah Ben , Toumi Toufik
Published: December 2019

The use of loads in the past few days is becoming vast, giving an alarm signal to the power system and electronics engineers in terms of power quality. Due to the large amount of non-linear power electronics, utilities frequently experience voltage and harmonic distortions every day. In this paper, the combination of the Series active power filter SAPF with a PV source is deliberated. The PV based on the SAPF aims to compensate voltage deviations or disturbances that occur in the system caused by power quality issues. The proposed system consists of a PV source connected to the DC link through two dc-dc converters, the first extracts the maximum power of the PV source through pulse with modulation PWM signals generated from the maximum power point tracker MPPT controller. Thus, the second converter is used to regulate the high voltage side of the converter through closed control loops using Fuzzy Logic Controller FLC, in addition to a voltage source inverter VSI and a series injection transformer. Despite of fluctuations of the DC link during the compensation of the needed energy, MPPT and closed control loops generate PWM signals to the switching devices of dc-dc boost converters in order to extract maximum PV power and to maintain the bus voltage within its limits and around its reference values respectively. The proposed topology is simulated in Matlab Simulink software, where simulation results show that the proposed PV based SAPF can efficiently reduce problems of voltage sag and harmonic.
Single-bit modulator for wireless power transfer system
Authors: Almakhles Dhafer , Swain Akshya , Subramaniam Umashankar
Published: December 2019

This paper proposes a single-bit ADC system based Proportional and Integral (PI) controller to maintain a desired level of power transfer efficiency in Capacitive Power Transfer (CPT) systems. In this paper, a simple single-bit ADC system i.e., Single-Bit Modulator (SBM) is considered as an alternative to the commonly used multi-bit ADC systems. Unique features of employing SBM are 1) its ability to convert analog signals into single-bit signals and 2) its easy integrability in digital chips with linear variable differential transformers (LVDTs) such as FPGAs. A SBM based PI (SBM-PI) controller is designed to judicially interface with the single-bit output of SBM. The proposed (SBM-PI) controller guarantees less hardware resources, latency and regulates the output voltage to provide the desired power transfer efficiency. The behavior of SBM-PI controller is compared to that of a conventional multi-bit controller, with the results of both controllers being identical. The effectiveness of the proposed controller with SBM is further demonstrated using the experimental prototype of CPT by implementing a SBM-PI controller using $16$ MHz ATmega8 microcontroller. The experimental results from a laboratory prototype illustrate that SBM-PI controller successfully regulates the output voltage of CPT to control the power flow.
Comparison of solar based closed loop DC-DC converter using PID and ANN control for shunt motor drive
Authors: Jayaprakash S. , Ramani R. , Kavitha M. , Nayagam V. Senthil
Published: December 2019

This paper explained details of Comparison of solar based closed loop DC -DC converter using PID and ANN Control for Shunt motor drive. Solar panel output is given to full bridge converter, stepup transformer, full wave converter, ∏ filter and Shunt motor drive are connected.Comparator compare the set value and the output signal of the motor produce a signal, based on the signal, full wave conveter produce the voltage to run the motor, Speed of motor,Torque and Armature current,Rise time,Peak time, Settling time and Steady state error are measured and evaluated by experimental.A circuit operation and simulation designed for a 1000 RPM speed of shunt motor arrived and tested.
High performance PV system based on artificial neural network MPPT with PI controller for direct current water pump applications
Authors: Attia Hussain
Published: December 2019

This paper presents a new design of a standalone photovoltaic system which is supplying the required power to a direct current water pump that have difficulty to supply by the utility electricity. The system is controlled by an artificial neural networks (ANN) algorithm with function softening by PI controller that to guarantee the maximum power point tracking (MPPT) working conditions. A parallel connected PV array is designed to supply the required power to the water pump. The proposed design considers Permanent Magnet DC motor (PMDC) of 48 Volts, and 500 Watts as a water pump’s motor, the direct current (DC) pump is adopted to avoid the complexity of the alternating current AC pumping system which includes inverter, power filter, and insulated step up transformer, so the presented design avoids the mentioned AC system components. A feed forward ANN algorithm is adopted in this study to produce the reference voltage for the MPPT functioning of the PV system, Proportional Integral (PI) controller is inserted to soften the MPPT controller performance. System design, MATLAB simulation with results and the results’ analysis all are presented in this paper. The study conclusion confirms the effectiveness of the proposal as a successful system for practical applications. 
A piecewise affine PI controller for buck converter generated DC motor
Authors: Hanif Mohd Ikhmil Fadzrizan Mohd , Suid Mohd Helmi , Ahmad Mohd Ashraf
Published: December 2019

This paper presents a new Piecewise Affine Proportional-Integral (PA-PI) controller for angular velocity tracking of a buck converter generated dc motor. A Safe Experimentation Dynamics (SED) algorithm is employed as a data-driven optimization tool to find the optimal PA-PI controller parameters such that the integral square of error and input are reduced. The essential feature of the PA-PI controller is that the parameters of proportional and integral gains are adaptive to the error variations according to the Piecewise Affine (PA) function. Moreover, the proposed PA function is expected to provide better control accuracy than the other existing variable structure PID controller. In order to verify the effectiveness of the PA-PI controller, a widely known buck converter generated dc motor is considered. The performances of the proposed controller are observed in terms of the integral square of error and input, and the responses of the angular velocity and duty ration input. The simulation results verify that the proposed PA-PI controller yields higher control accuracy than the other existing controllers of buck converter generated dc motor.
Bridgeless PFC single ended primary inductance converter in continuous current mode
Authors: Rai Nor Akmal , Aziz Mohd Junaidi Abdul , Sahid Mohd Rodhi , Ayob Shahrin Md.
Published: December 2019

This paper presents bridgeless single ended primary inductor (SEPIC) converter operated in continuous conduction mode (CCM). The converter used in the study offers a lesser conduction loss compared to the other bridgeless SEPIC converter.   In order to regulate the required output current and output voltage with high efficiency while achieving high power factor correction (PFC) at the input side, average current mode control (ACMC) is applied. The model is simulated using MATLAB/Simulink and it is found that the converter and the proposed control strategy provide a promising result. The preliminary results obtained from the experimental test-rig shows a good agreement as in simulation. The theoretical analysis of the proposed controller is verified on an output 100V to 300W prototype.
Development of active power filter using rectifier boost technique
Authors: Osman Dygku Aniqnatasa Awg , Baharom Rahimi , Johari Dalina , Hidayat Muhamad Nabil , Muhammad Khairul Safuan
Published: December 2019

The development of active power filter (APF) using rectifier boost technique has been identified to compensate for the pulsating nature of the distorted supply current waveform of non-linear load. In this work, investigation is carried out on the operation of rectifier without any filters function. This is then extended to operate the rectifier converter with an active power filter function. APF function is implemented by enabling the closed-loop control using standard proportional integral control to rectify the distorted supply current to become continuous, sinusoidal and in-phase with the supply voltage waveform. Consequently, the total harmonic distortion (THD) level was reduced to meet the acceptable limit defined in the standard of IEEE-519 1992. The selected simulation results obtained from MATLAB/Simulink are presented to justify the proposed filter structure.
Enhanced decoupled current control with voltage compensation for modular multilevel converter (MMC) based STATCOM
Authors: Lawan Abdurrahman Umar , Almurib Haider A.F. , Khor Jeen G.
Published: December 2019

This paper presents the application of modular multilevel converter (MMC) as a static compensator (STATCOM) for reactive current control. The current control is mostly achieved using proportional controller, proportional-integral (PI) controller, and hysteresis controller among others. PI controllers have the advantage of low harmonics and small variations.  However, due to the PI controller’s dependency on the system parameters and also due to the variations within the MMC during capacitors voltage control, variation in the MMC performance during the STATCOM non-ideal operations occur. To mitigate this, an improved performance of MMC will be presented using vector-based compensation concept. The proposed control will be introduced to depress the effect of the dynamics of the MMC based STATCOM non-ideal variations considering the impact of the voltage disturbance. This will be achieved by the introduction of voltage variables to subtract the transient variations from PI controllers’ outputs at the grid-interface; thus, improving the performance.
Control of the photoelectric generator for used in feeding of the independent wind turbine system
Authors: Kendzi Mohammed , Aissaoui Abdelghani , Abid Mohamed , Tahour Ahmed
Published: December 2019

In this paper, a hybrid power system is proposed to eliminate any interruption caused to absence of power supply network by the Fusion between the wind source and the photovoltaic source to create a hybrid system with internal power supply autonomy. The hybrid power system includes a solar and wind source whose wind energy conversion system is based on a doubly fed induction generator. The photovoltaic conversion system extracts the maximum power from the sun. A part of this power is used to supply the rotor of a doubly fed induction generator; the rest is injected in the grid. The connection between the two conversion systems is made by means of static converters (chopper/inverter). In the photovoltaic conversion chain, a controller for tracking the maximum power point is designed using the direct search approach the Perturb and observe method. The wind energy conversion system contains a doubly fed asynchronous generator with a control system of generated powers by the technique of the fuzzy logic. The simulation was done to prove the validity of the strategy and of the control method used for the control of the power generated by the hybrid system.
Design of solar photovoltaic pressurized drip irrigation pumping system at al-salman district in samawa governorate
Authors: Mejeed Raghad Ali , Oudah Samah Shyaa , Abed Rasha Yasen
Published: December 2019

The seasonal climate changes have direct effects on determination of crop water requirement, irrigation scheduling and the potential of solar energy generation to operate the pumping system for watering crops. This research paper studied the technical evaluation of solar pumping and pressurized drip irrigation systems to investigate the recommended water required for suggested tomatoes crop in area of (one hectare) at AL-Salman district using measured climatic data from AL-Salman Agro-meteorological weather station for a period (2013-2017). The maximum average monthly of solar radiation was 7.6 kWh/m2 at June in all the years of recording data, while the minimum average monthly value was 3.37kWh/m2 at December where the sun at lowest point across the sky. The annual average hours of peak sun that corresponds to the operation time of the pumping system at maximum water consumption was calculated at eight months from March to October with a value of 7.2 hours/day, while it was 5.2 hours/day during the other four months (January, February, November and December). The Solar pumping sizing based on H-Q performance curve of a maximum flow rate of 64.45 m3/h and pump capacity of 16.79 kW with compounds motor pump efficiency of 61.2%. The total water production was 230000 m³/per year which indicates compatible overall system design and adequate to irrigate more planting land with same or other crop types.
A new high performance variable step size perturb-and-observe MPPT algorithm for photovoltaic system
Authors: Saidi Khadidja , Maamoun Mountassar , Bounekhla M’hamed
Published: December 2019

The optimization of energy in a photovoltaic conversion chain remains a topic of study. The maximum power point tracking (MPPT) is considered the most appropriate solution to ensure the extraction of the maximum power which a photovoltaic generator can provide. Perturb and observe (P&O) algorithm is the well-known MPPT tracker; it shows an important and decisive role in the development of photovoltaic (PV) systems. In This article we introduce a new improved adjustable step size P&O (imVS_PO) MPPT method.The performances of the new algorithm are compared to the conventional P&O MPPT techniques and to the existing adjustable step size P&O (VS_PO) MPPT algorithm. The results clearly show the efficiency of the improved algorithm which contributed to the increase of the tracking speed with negligible fluctuations when the MPP is reached, and especially in rapid variation of insolation.
Fault detection and classification in wind turbine by using artificial neural network
Authors: Fadzail N. F. , Zali S. Mat
Published: December 2019

Wind turbine is one of the present renewable energy sources that has become the most popular. The operational and maintenance cost is continuously increasing, especially for wind generator. Early fault detection is very important to optimise the operational and maintenance cost. The goal of this project is to study fault detection and classification for a wind turbine (WT) by using artificial neural network (ANN). In this project, a single phase fault was placed at 9 MW doubly-fed induction generator (DFIG) WT in MATLAB Simulink. The WT was tested under different conditions, i.e., normal condition, fault at Phase A, Phase B and Phase C. The simulation results were used as inputs in the ANN model for training. Then, a new set of data was taken under different conditions as inputs for ANN fault classifier. The target outputs of ANN fault classifier were set as ‘0’ or ‘1’, based on the fault condition. Results obtained showed that the ANN fault classifier outputs had followed the target outputs. In conclusion, the WT fault detection and classification method by using ANN were successfully developed.
Speed performance evaluation of BLDC motor based on dynamic wavelet neural network and PSO algorithm
Authors: Obed Adel Ahmed , Saleh Ameer Lateef , Kadhim Abbas Kareem
Published: December 2019

In this paper, several methods are developed to control the brushless DC (BLDC) motor speed. Since it is difficult to get a good showing by utilizing classical PID controller, the Dynamic Wavelet Neural Network (DWNN) is the proposed work in this paper, with parallel PID controller to obtain an novel controller named DWNN-PID controller. It collects the artificial neural ability of its networks for imparting from motor of BLDC with drive system and the ability of identification for the wavelet decomposition and control of the dynamic system furthermore to have ability for adapting and self-learning.  The suggested controller method is utilizing to control the speed of BLDC motor of which supply a better showing than utilizing classical controllers with a wide range of control. The proposed controller parameters are matched continuously using Particle Swarm Optimization (PSO) algorithm. The simulation results based on proposed DWNN-PID controller demonstrate a superior in the stability and performance compared at utilizing classical WNN-PID and conventional PID controllers. The simulation results are accomplished using Matlab/Simulink. It shows that the proposed control scheme has a superior performance.
Design and optimization of HTS flux-switching permanent magnet machine
Authors: Shuraiji Ahlam Luaibi , Al-ani M.M.J.
Published: December 2019

Flux-switching permanent magnet (FSPM) machine with high temperature superconductors (HTS) bulks located between the rotor poles to eliminate the flux leakage in the rotor, termed as (HTS-FSPM) machine has been proposed in this paper. Using genetic algorithm, the HTS and the conventional FSPM machines having the same size constraints and load conditions have been globally optimized for max. aveage torque. To highlight the advantages of the HTS-FSPM machine, a performance comparison between the conventional and HTS-FSPM machines has been presented. It is found that the HTS-FSPM machine can increase the torque by 27%, however, this comes with the expense of higher torque ripple and power losses.  
A smart cascaded H-bridge multilevel inverter with an optimized modulation techniques increasing the quality and reducing harmonics
Authors: Babkrani Youssef , Naddami Ahmed , Hilal Mohamed
Published: December 2019

The world community relied heavily on fossils energies but just after the big oil crisis the use of renewable energy has greatly increased and has become the main interest of many countries for its many advantages such as: minimal impact on the environment, renewable generators requiring less maintenance than traditional ones and it has also a great impact on economy. It is easy to get charmed by the advantages of using the renewable resources but we must also be aware of their disadvantages. One of the major disadvantages is that the renewable energy resources are intermittent and thus they have led scientists to develop new semiconductor power converters among which are the multilevel inverter. In this paper a new smart multi-level inverter is proposed so as to increase its levels according to the user’s needs and also to avoid the impact of shades and the intermittence on photovoltaic panels. We also propose a modification on the multicarrier aiming to reduce the harmonics. This modification introduces a sinusoidal wave compared with trapezoidal multi-carrier to generate the pulses. In order to obtain the line voltages and the total harmonic distortions (THD) MATLAB/SIMULINK is used.