bluuebunny/crossref_metadata_2025 huggingface dataset:
Recurrent Pneumothorax in a Critically Ill Ventilated COVID-19 Patient
Authors: Rehnberg Lucas , Chambers Robert , Lam Selina , Chamberlain Martin , Dushianthan Ahilanandan
Published: September 2020

We present this case of a young woman with SARS-CoV-2 viral infection resulting in coronavirus 2019 (COVID-19) lung disease complicated by a complex hydropneumothorax, recurrent pneumothorax, and pneumatoceles. A 33-year-old woman presented to the hospital with a one-week history of cough, shortness of breath, and myalgia, with no other significant past medical history. She tested positive for COVID-19 and subsequently, her respiratory function rapidly deteriorated, necessitating endotracheal intubation and mechanical ventilation. She had severe hypoxic respiratory failure requiring a protracted period on the mechanical ventilator with different ventilation strategies and multiple cycles of prone positioning. During her proning, after two weeks on the intensive care unit, she developed tension pneumothorax that required bilateral intercostal chest drains (ICD) to stabilise her. After 24 days, she had a percutaneous tracheostomy and began her respiratory wean; however, this was limited due to the ongoing infection. Thorax CT demonstrated a left-sided pneumothorax, with bilateral pneumatoceles and a sizeable, complex hydropneumothorax. Despite the insertion of ICDs, the hydropneumothorax persisted over months and initially progressed in size on serial scans needing multiple ICDs. She was too ill for surgical interventions initially, opting for conservative management. After 60 days, she successfully underwent a video-assisted thoracoscopic surgery (VATS) for a washout and placement of further ICDs. She was successfully decannulated after 109 days on the intensive care unit and was discharged to a rehabilitation unit after 116 days of being an inpatient, with her last thorax CT showing some residual pneumatoceles but significant improvement. Late changes may mean patients recovering from the COVID-19 infection are at increased risk of pneumothoracies. Clinicians need to be alert to this, especially as bullous rupture may not present as a classical pneumothorax.
Efficacy of Omalizumab Therapy in an Asthmatic with Low IgE
Authors: R Divya , Venkitakrishnan Rajesh , Augustine Jolsana , Cleetus Melcy
Published: September 2020

Asthma is one of the most common respiratory diseases encountered in clinical practice. Although the vast majority of asthmatics can be adequately controlled with inhaled steroids and other preventer medications, a small proportion remain uncontrolled. Anti-IgE treatment with omalizumab has been proposed in patients as a preferred approach in step 5 asthma therapy according to GINA guidelines. Although therapy with this molecule is approved for patients with atopic asthma and pretreatment serum IgE levels of 30-1500 only, there have been a few reports of its efficacy in subjects outside this reference IgE range. We report the case of a middle-aged lady with severe corticosteroid-dependent asthma and low serum IgE levels who was successfully treated with 9 months of omalizumab therapy. She gained good asthma control and was tapered off steroid use by the fifth month of therapy with omalizumab. The case report stresses the need for further investigation into expanding the spectrum of omalizumab usage in asthma beyond the current IgE suitability range.
Previously Unidentified Gene Variation Associated with Fabry Disease: The Impact on One Family
Authors: Vanga Amaresh R. , Schrier Vergano Samantha A. , Kowalewska Jolanta , McCune Thomas R.
Published: September 2020

Fabry disease is an X-linked lysosomal storage genetic disorder associated with over 1000 mutations in the alpha-galactosidase-A gene region. We report here a 69-year-old male who underwent a kidney biopsy to evaluate progressive renal failure. He was found to have zebra bodies in visceral epithelial cells on biopsy, with electron microscopy showing inclusions within the cytoplasm of multiple podocytes consistent with Fabry disease. An alpha-galactosidase level was found to be 21 nm/hr/mg (normal range 50–150 nm/hr/mg). Genetic studies revealed a missense variant in the GLA gene with alanine replaced by cysteine at position 682 (c.682 A > C, p.N228H) that had not been previously associated with Fabry disease. The same variant was detected in two additional family members. The pathologic findings, clinical features, and low alpha-galactosidase level suggest that the c.682 A > C variant is associated with Fabry disease.
Vitamin D Deficiency in Autism Spectrum Disorder: A Cross-Sectional Study
Authors: Petruzzelli Maria G. , Marzulli Lucia , Margari Francesco , De Giacomo Andrea , Gabellone Alessandra , Giannico Orazio V. , Margari Lucia
Published: September 2020

Vitamin D plays a role in central nervous system (CNS) development. Recent literature focused on vitamin D status in children and adolescents with autism spectrum disorder (ASD), but with inconsistent results. Our case-control study is aimed at evaluating serum 25-hydroxyl-vitamin D (25(OH)D) concentration in children with ASD (ASD group, n=54) compared to children affected by other neurological and psychiatric disorders (non-ASD group, n=36). All patients were admitted at the Complex Operative Unit of Child Neuropsychiatry, Polyclinic of Bari, Italy. 25(OH)D was quantified by chemiluminescence immunoassay and level defined as: deficiency (<20 ng/mL); insufficiency (20–30); normality (30-100); toxicity (>100). Statistical analysis was performed using SPSS20 (significance<0.05). The ASD group showed 25(OH)D a mean level significantly lower than control (p=0.014). Multivariable logistic regression analysis showed an association between ASD and vitamin D deficiency (p=0.006). The nature of such association is unclear. Vitamin D deficiency may probably act as a risk factor for the development of ASD. Further studies are needed to unravel the role of vitamin D in ASD etiology and investigate its therapeutic potential.
Convergence Analysis of H(div)-Conforming Finite Element Methods for a Nonlinear Poroelasticity Problem
Authors: Zeng Yuping , Weng Zhifeng , Liang Fen
Published: September 2020

In this paper, we introduce and analyze H(div)-conforming finite element methods for a nonlinear model in poroelasticity. More precisely, the flow variables are discretized by H(div)-conforming mixed finite elements, while the elastic displacement is approximated by the H(div)-conforming finite element with the interior penalty discontinuous Galerkin formulation. Optimal a priori error estimates are derived for both semidiscrete and fully discrete schemes.
Cytoprotective Effect of Astaxanthin in a Model of Normal Intraocular Pressure Glaucoma
Authors: Kikuchi Kasumi , Dong Zhenyu , Shinmei Yasuhiro , Murata Miyuki , Kanda Atsuhiro , Noda Kosuke , Harada Takayuki , Ishida Susumu
Published: September 2020

Glaucoma is characterized by axonal degeneration of retinal ganglion cells (RGCs) and apoptotic death of their cell bodies. Lowering intraocular pressure is currently the only way to treat glaucoma, but it is often insufficient to inhibit the progression of the disease. Glaucoma is a multifactorial disease, and the involvement of oxidative stress has recently received much attention. In the present study, we investigated the cytoprotective effect of astaxanthin (AST) on RGC degeneration using a normal-tension glaucoma (NTG) mouse model, which lacks the glutamate/aspartate transporter (Glast) and demonstrates spontaneous RGC and optic nerve degeneration without elevated intraocular pressure. Three-week-old Glast± mice were given intraperitoneal injections of AST at 10, 30, or 60 mg/kg/day or vehicle alone, and littermate control mice were given vehicle alone for 14 days, respectively. Five weeks after birth, the number of RGCs was counted in paraffin sections of retinal tissues stained with hematoxylin and eosin. We also used a retrograde labeling technique to quantify the number of RGCs. Additionally, the phosphorylated (p) IκB/total IκB ratio and the 4-hydroxynonenal (HNE) were measured in retinal tissues. The number of RGCs in Glast± mice was significantly decreased compared with that in control mice. RGC loss was suppressed by the administration of AST at 60 mg/kg/day, compared with vehicle alone. Following AST administration, the concentration of 4-HNE in the retina was also suppressed, but the pIκB/IκB ratio did not change. Our study revealed that the antioxidative stress effects of AST inhibit RGC degeneration in the retina and may be useful in the treatment of NTG.
Fundamental elements of constant volt/hertz induction motor drives based on dSPACE DS1104 controller
Authors: Mahsahirun Siti Nursyuhada , Nik Idris Nik Rumzi , Yusof Zulkifli Md. , Sutikno Tole
Published: September 2020

An induction motor (IM) has been the workhorse of the industry for decades. It is due to its robustness, simple construction, requiring less maintenance and cheap. One of the most widely adopted IM drive control schemes for industrial applications is the open-loop constant V/Hz. In this paper, the important elements of an open-loop constant V/Hz drives are presented. These include the fundamental concept of a constant V/Hz scheme, the voltage source inverter (VSI) and its modulation schemes. Techniques that are commonly used to solve problems of low-speed operation and rotor speed regulation are briefly described. Simulations using MATLAB/Simulink package are used to help in illustrating these fundamental concepts. Finally, simple laboratory-scale experiments are conducted to implement the constant V/Hz control scheme on a ¼ hp induction motor. The constant V/Hz control is implemented using the DS1104 controller board with the C codes automatically generated from the Simulink model. A closer look at the current waveform when fref=25 Hz and 12 Hz and its respective Fourier analysis are presented. The results show that the high-frequency harmonic contents around the switching frequency can be observed for both cases, and the voltage waveform presents more spike noises in constrast to  current waveform.
Experimental installation of wireless power transfer system based on the series resonance technology
Authors: Al-Chlaihawi Sarab , Tawafan Adnan Hasan , Abd Fatima Kadhem
Published: September 2020

In this work, we aim to install a wireless power transfer (WPT) system experimentally. Series resonance technology was used to achieve zero-voltage switching (ZVS). We investigated the impact of the primary and secondary resonance frequencies (fp and fd), and inverter frequency switching (fch) on the efficiency (β) and maximum transfer power in a WPT system based on the inductive wireless power transfer (IWPT) technology. An ultrasonic device was utilized as a generator to excite the coil at the primary side. The experimental outcomes showed that there is an optimum unlike fp and fd can be got to match fch. It was found also that there is a trade-off between the power supplied to the load (PRL) and DC-DC efficiency (β). At an air-gap of 5 cm, the obtained results are recorded as follows; the peak recorded system β is 62% that was obtained at fp=19 kHz, fd=fch=24 kHz that is corresponding to 101.88W of PRL; whereas the highest PRL resulted i.e. 244W when fp=19 kHz, fd =24 kHz, fch=21 kHz at 61% of β; in such case, the maximum β* PRL multiplication was achieved i.e. 149. Moreover, the coils’ misalignment was studied. The outcomes showed that the lateral misalignment has worst effect on the PRL and β than the air-gap. The experimental results were validated with simulation ones.
Experimental implementation PWM strategy for dual three-phase PMSM using 12-sector vector space decomposition applied on electric ship propulsion
Authors: Hasoun Mhammed , El Afia Aziz , Khafallah Mohamed , Benkirane Karim
Published: September 2020

The current paper aims at presenting and examining an implementation on a digital signal processor (DSP) of the conventional space vector pulse width modulation (CSVPWM) so as to control the dual three phase permanent magnet synchronous motors (DTP-PMSM) drives applied on electric ship propulsion. It is also an attempt to accomplish a developed control of this technique based on vector space decomposition (VSD) strategy. By this strategy, the analysis and the control of the machine are achieved in three two-dimensional orthogonal subspaces. Among the 12 voltage vectors having maximum, the conventional technique namely the adjacent two-vectors (12SA2V) is chosen. Thereby, the test platform allows the implementation of the chosen vectors which are modeled on MATLAB/Simulink using block diagrams and the automatically generated code which is targeted in the DSP card processor. Simulation and experimental results have exposed the efficiency of the proposed test bench of 5 KW prototype machine by using a low-cost TMS32F28379D.
Novel approach for SVPWM of two-level inverter fed induction motor drive
Authors: Elkholi Olwi A. , Enany Mohamed A. , Abdo Ahmed F. , Eid Mahmoud
Published: September 2020

Due to their better DC bus utilization and easier digital realization, Space Vector Pulse Width Modulation (SVPWM) scheme is the most widely used PWM scheme. Also two level inverter is the traditional frequency converter because it has fewer components and is lower complex to control, but on the other hand it generates higher harmonic distortion. This paper presents the realization of novel SVPWM approaches applied to the three phase induction motor drives. Specifically various schemes are based on using more combinations of step operation in each cycle to approximate the reference vector, such as 24 and 48 step operations in each cycle. The basic principle of conventional SVPWM with different modulation index M is presented. The switching sequences of new approaches are described. The modulation signals waveforms, DC bus voltage utilization, De-rated motor torque, standard error of average torque, voltage and current harmonic of new approaches are analyzed by the MATLAB/SIMULINK software. The results confirms that 48 step SVPWM approach is the best compared to other approaches.
Modulation index effect on inverter based induction motor drive
Authors: Sharma Akhilesh , N. Anandh , Gao Sarsing
Published: September 2020

Due to a substantial increase in the use of inverter for numerous electrical appliances starting from domestics to industrial drives, an inverter may be directly connected to the power grid system. The dependency on an inverter has been increased over the years. Hence, the proper and efficient design of the inverter will lead to higher efficiency. One of the major challenges is the generation of suitable gate pulses for power switching devices, which in turn depends on the modulation index. The selection of proper modulation index will help in the production of the rated voltage. If the modulation index is less, the duration of on-time pulses will be less and hence, the device's conduction time is also less, thereby the output voltage of the inverter is reduced. A reduced voltage, when applied to an induction motor will have lower speed and even its performance will be sluggish. The speed of the motor improves when it is operated in a closed-loop for the same modulation index. This research paper tries to bring out the effect of modulation index on speed control of an induction motor based on an inverter for both open as well as closed-loop operation. The simulated results indicate that the modulation index in the vicinity to unity will provide rated voltage for the smooth operation of the motor.
Selection the optimum place of FACTS devices using fuzzy control system
Authors: Hameed Jawad , Mohammed Hameed Ali , Saeed Amer T.
Published: September 2020

In this paper, the voltage stability of the power system is studied during fault conditions. Enhancement of the system’s stability will be achieved by utilizing Flexible AC transmission systems (FACTS) controllers at the best place in the system. The optimum placement of (FACTS) controllers occurred on the most affected bus by the fault in the system (weakest bus). Two approaches have been used in this study to effectively obtain the best location of the (FACTS) controllers in the system. The first method is based on computing the deviation which occurs in the active power and reactive power due to the fault at each load bus at a time. Whereas the second method is performed through exploiting a MATLAB fuzzy set technique utilizing two indices: Line Flow Index (LFI) and Voltage Profile Index (VPI) during fault and steady-state conditions. The results show that both of these indices resulted in the same bus as the best location. Remedial actions in the attempt at improving in the stability of the power system are discussed taking the advantage of using (FACTS) compensation (SVC) and (STATCOM) at the most vulnerable system buses. In this work, MATLAB program with an IEEE 24 bus system is examined.
An improved zero-voltage zero-current transition boost converter employing L-C-S resonant network
Authors: N Anandh , Sharma Akhilesh , S Julius Fusic , H Ramesh
Published: September 2020

An improved zero-voltage zero-current transition boost converter (IZVZCTBC) is introduced. This converter is basically a fourth-order DC-DC converter wherein a L-C-S (Inductor–Capacitor–Switch) resonant circuit is embedded for soft-switching. L-C-S tank network is the modified version of conventional ZVZCT switch cell. The main feature of L-C-S tank circuit is to enhance the performance of zero-voltage zero-current transition boost converter in terms of eliminating the high current stress, decreasing the switching losses and increasing the efficiency of converter. This converter exhibits both zero-voltage turn on and zero-current turn off switching characteristics based on the gating signals applied to switches. The principle of operation and time domain expressions of IZVZCT boost converter with L-C-S cell are presented. For the closed loop operation, digital controller is designed and the performance of the controller has been validated through simulation for different line and load variations. The mathematical and theoretical analysis is verified accurately by a 12-24 V, 30 W converter through PSIM simulation software and the results ensures that overall efficiency of the converter has improved to 97% along with elimination of current stress.
A narrative 3-phase 9-level voltage source inverter
Authors: Selvaperumal M. , Kirubakaran D.
Published: September 2020

A tale technique for a 3-stage nine-level voltage source inverter utilizing sixteen switches is presented. The given system utilizes ordinary 3-stage scaffolds of two-level as a diode braced model. A DC interface voltage is provided so that the fell H-connect produces the nine voltage levels. The exchanging designs are expressed as the levels expand then the example is hard to create three-stage yields with key balance procedures. Here an answer for an a-level inverter to create required voltage-level with less power electronic parts by setting up in the look-into tables. This investigation diagrams the correlations between nine-level voltage source inverters in various arrangements and proposed novel, sixteen switch three-stage inverter structured with a smaller number of intensity electronic parts and reenacted in MATLAB/Simulink.
A high-performance multilevel inverter with reduced power electronic devices
Authors: Chlaihawi Amer , Sabbar Adnan , Jedi Hur
Published: September 2020

This paper introduces a new topology of multilevel inverter, which is able to operate at high performance. This proposed circuit achieves requirements of reduced number of switches, gate-drive circuits, and high design flexibility. In most cases fifteen-level inverters need at least twelve switches. The proposed topology has only ten switches. The inverter has a quasi-sine output voltage, which is formed by level generator and polarity changer to produce the desired voltage and current waveforms. The detailed operation of the proposed inverter is explained. The theoretical analysis and design procedure are given. Simulation results are presented to confirm the analytical approach of the proposed circuit. A 15-level and 31-level multilevel inverters were designed and tested at 50 Hz.
A new space vector modulation technique for quasi Z-source B4 inverter
Authors: Mustafar Izni , Azli Naziha A. , Nordin Norjulia M.
Published: September 2020

A Quasi Z-Source (qZS) network has been utilized in a B4 inverter topology to provide voltage boosting effect by turning on the upper and lower switches simultaneously which is known as zero shoot-through states. However, the design of a qZS B4 inverter is not as straightforward as adding a qZS LC impedance network to the front-end of a B4 inverter. This is because there is no zero vectors available in a B4 inverter topology to insert the shoot through zero states, as in the case of a B6 inverter. This paper proposes a new Space Vector Modulation (SVM) technique for a qZS B4 inverter. Additional zero vectors have been appropriately added and distributed in the proposed SVM to avoid altering the existing volt-sec per switching cycle for the existing active vectors. The voltage vectors switching placement is carefully designed in order to enable the voltage boosting effect for this topology without altering the initial output voltage. In addition, an approach to compensate the DC-link voltage ripple has also been taken into consideration in its initial calculation to achieve balanced output voltage. The performance of the proposed modulation technique is verified using MATLAB/Simulink. It is shown that by using the proposed modulation technique, there is an overall improvement on the line to line output voltage where by it is able to produce balanced output voltages for the three-phase loads with or without boosting effect.
New adaptive hysteresis band width control for direct torque control of induction machine drives
Authors: Kadum Arkan A.
Published: September 2020

This paper presents a new adaptive hysteresis band control approach used in direct torque control (DTC) of the induction motor (IM) drives with the switching tables for the generation of PWM signals. Constant Hysteresis Direct torque control (CHB-DTC) method used the torque and stator flux errors to generate the stator voltage reference and frequency vectors for controlling the three-phase induction motor. The CHB-DTC gives better torque transient performance but it has large steady state ripples. To reduce torque and stator current ripples in CHB-DTC controlled induction motor drives a new adaptive hysteresis band control (AHB) approach is proposed, where the hysteresis band is adapted in real time with the stator flux and torque errors variation, instead of fixed bandwidth. Both classical CHB-DTC method and the proposed adaptive hysteresis band DTC (AHB-DTC) fed three induction motor have been simulated using Matlab/Simulink. The simulation results at different operating conditions over a wide speed range demonstrate the validity, effectiveness, and feasibility of the proposed scheme. The measurements showed that torque ripples were significantly decrease with the new AHB-DTC technique and better speed response in step up or down compared to the CHB-DTC.
Evaluation of DC-DC converter using renewable energy sources
Authors: B Rajapandian , G.T Sundarrajan
Published: September 2020

This work analyses and evaluates the performance of renewable energy sources-based converters using Intelligent techniques. The objective of the research is to maintain the reliability of the converters such that it decreases the switching losses, high duty cycle and recycles the leakage energy. To accomplish the high output voltage gain converters are designed with different intelligent methods. Due to heavy demands, the cost of fossil fuel has gone up.so the need for the time is identifying and developing renewable energy sources along with developing new technologies for energy saving in renewable energy system to fight the issues plaguing the environment.
Improvement of the performance of STATCOM in terms of voltage profile using ANN controller
Authors: Alatshan Mohammed Salheen , Alhamrouni Ibrahim , Sutikno Tole , Jusoh Awang
Published: September 2020

The electronic equipments are extremely sensitive to variation in electric supply. The increasing of a nonlinear system with several interconnected unpredicted and non-linear loads are causing some problems to the power system. The major problem facing the power system is power quality, controlling of reactive power and voltage drop. A static synchronous compensator (STATCOM) is an important device commonly used for compensation purposes, it can provide reactive support to a bus to compensate voltage level. In this paper, the Artificial Neural Network (ANN) controlled STATCOM has been designed to replace the conventional PI controller to enhance the STATCOM performance. The ANN controller is proposed due to its simple structure, adaptability, robustness, considering the power grid non linearities. The ANN is trained offline using data from the PI controller. The performance of STATCOM with case of Load increasing and three-phase faults case was analyzed using MATLAB/Simulink software on the IEEE 14-bus system. The comprehensive result of the PI and ANN controllers has demonstrated the effectiveness of the proposed ANN controller in enhancing the STATCOM performance for Voltage profile at different operating conditions. Furthermore, it has produced better results than the conventional PI controller.
Modeling of battery pack sizing for electric vehicles
Authors: Sandeep V. , Shastri Suchitra , Sardar Arghya , Salkuti Surender Reddy
Published: September 2020

The paper presents the mathematical modeling for battery pack sizing to evaluate the vehicle energy consumption by using the derivation from Parametric Analytical Model of Vehicle Energy Consumption (PAMVEC) by Simpson in R Studio. The assess of storage batteries for electric vehicles (EVs) application is presented in this paper. The main source of power in EVs are batteries and to properly optimize their use in them, a parametric vehicle dynamic model is created and factors like battery mass, energy needed for the EV etc. are predicted using inputs such as battery specific energy, range etc. An assessment of output parameters is performed by using different batteries and compared to determine best battery for EV application.
Robust non-linear control of a hybrid water pumping system based on induction motor
Authors: Massaq Zakaria , Abounada Abdelouahed , Ramzi Mohamed
Published: September 2020

This contribution presents a non-linear control of a hybrid pumping system supplied with a photovoltaic generator and a battery. This system is employed for delivering a continuous volume of water whatever the climatic conditions. In the DC side, a boost converter is controlled with the indirect double integral sliding mode controller (DISMC) for maximum power point tracking (MPPT). The DISMC is suitable for MPPT because it gives a fast response and reduces the amplitude of power oscillations. Then, a bidirectional buck-boost converter is adopted to ensure the energy management between the battery and the DC-bus, and this converter is controlled with integral sliding mode control (ISMC) theory.  The non-linear predictive control (NPC) is chosen to drive an induction motor (IM), the NPC is known by its fast dynamic and high capacity to reject disturbances. The hybrid system is modelled in MATLAB/Simulink software. During simulations, the DISMC-MPPT is compared with other techniques such as sliding mode controller (SMC) MPPT and integral SMC MPPT, the DISMC provides the best tracking performances under different irradiances. Moreover, the designed controller for the bidirectional converter regulates the DC-link voltage with better performances than the classical PI controller. Lastly, the NPC regulates the speed of the IM with high robustness.
Photovoltaic array maximum power point tracking via modified perturbation and observation algorithm
Authors: Numan Bahaa Abdulkhailq , Shakir Amina Mahmoud , Mahmood Anas Lateef
Published: September 2020

One drawback of PVs is their low efficiency. As the PVs have a unique maximum Power Point for a specified irradiation level, there must be an effective method for extracting maximum power from the PV module to raise the efficiency. Conventional Perturbation and Observation (P&O) is a simple algorithm for maximum power point tracking (MPPT) but it suffers from oscillation during steady state conditions and is deviated from the maximum power point during slow and rapid irradiation level change. This paper presents a modified P&O by adding variation in PV current as a third in addition to the voltage and power variation parameters. This new algorithm is capable of eliminating the MPPT deviation. To increase the perturbation speed, a double step is taken as the tracking is deviated from the MPP. The modified P&O algorithm is used to control the duty cycle of DC-DC buck converter. The simulation shows that the modified P&O is faster than the conventional. The power loss due to oscillation before attaining the steady state is less for modified P&O. For slow irradiation level change (ramp up 600 to 1000 and ramp down 1000-800) W/m2, the modified P&O shows less tracking diverge. As the irradiation level changes rapidly from 800 to 200 W/m2, it's shown that the modified algorithm attains the steady state faster than the conventional P&O and the average efficiency increased by 4.34%.
Novel technique for hill climbing search to reach maximum power point tracking
Authors: Badawi Ahmed Samir , Hasbullah Nurul Fadzlin , Yusoff Siti Hajar , Hashim Aisha H , Zyoud Alhareth
Published: September 2020

In this paper, a new technique has been proposed to solve the trade off common problem in hill climbing search algorithm (HCS) to reach maximum power point tracking (MPPT). The main aim of the new technique is to increase the power efficiency for the wind energy conversion system (WECS). The proposed technique has been combined the three-mode algorithm to be simpler. The novel algorithm is increasing the ability to reach the MPPT without delay. The novel algorithm shows fast tracking capability and enhanced stability under change wind speed conditions.
Optimal configuration of hybrid PV-generator (diesel/GPL) for a decentralized production of electricity in Algeria
Authors: Mohamed Amara , Abdelkader Zablah , Abdelkrim Bouanane
Published: September 2020

The absence of electricity in rural areas is one of the major challenges faced by many developing countries like Algeria. This work has been devoted to the design of an off-grid renewable hybrid power system for a rural village in the region of Tindouf located in south Algeria. The main objective of this study is to determine the optimum size of the hybrid power system able to fulfill the requirements of 709 kWh/day primary load with 66 kW peak load for a remote area of 230 households. This study is based on simulation and optimization of a (PV-Diesel) and (PV-GPL) hybrid system with a technical-economic analysis. Simulation results showed that electrifying using a PV/GPL generator hybrid system is more advantageous when compared to the PV/diesel generator hybrid system as it has lower operating costs and emissions. The comparison is based on per unit cost of electrical energy production, operating cost of conventional fossil fuel-based energy sources and pollutants gases reduction.
Islanding detection of distributed generation systems using hybrid technique for multi-machine system
Authors: Sirige Sindhura S. , Choudhury Sallena , N. S. Jayalakshmi
Published: September 2020

Due to depletion of conventional fuels and increase in power demand, many renewable energy sources are being integrated into the electrical grid. One of the major concerns with this integration of these renewable sources with utility grid is unintentional islanding. Many techniques have been proposed to detect unintentional islanding, all of them trying to comply with the IEEE standard 1547. This paper presents an analysis of the hybrid technique to detect the islanding condition of the power system with multi-machine systems. This work aims at analysing the technique against increasing size of the system with increasing number of distributed generators by including practical voltage unbalance formula. The validity of this detection technique is verified using IEEE standard test power systems in MATLAB platform. This method can be used to identify multiple islanding conditions effectively. The simulation results show the effectiveness of the technique to detect islanding condition for multi-machine systems.
Intelligent control of flywheel energy storage system associated with the wind generator for uninterrupted power supply
Authors: Amel Bensaid , Soraya Zebirate , Abdelkader Chaker
Published: September 2020

Wind energy is currently the fastest-growing energy source in the world. However, the inherent characteristic of intermittent energy production, due to the stochastic nature of wind, still comprises the main drawback of wind power. To avoid such problems, various configurations have been reccomended in order to reduce output power variation. The paper concentrates on performance benefits of adding energy storage system with the wind generator in order to regulate the electric power delivered into the power grid. Compared with other means of energy storage, the flywheel energy storage system (FESS) is the best choice to solve power quality problems. In this paper, a FESS associated to a variable speed wind generation (VSWG) is investigated by presenting two control strategies applied to the storage system equipped with an induction machine; both techniques are studied and developed and consist of a field control (FOC) and a Fuzzy Logic Control (FLC). Simulation model is established in MATLAB/Simulink and comparative results are then reported.
A real-time system for vehicle detection with shadow removal and vehicle classification based on vehicle features at urban roads
Authors: Atouf Issan , Al Okaishi Wahban Yahya , Zaaran Abdelmoghit , Slimani Ibtissam , Benrabh Mohamed
Published: September 2020

Monitoring traffic in urban areas is an important task for intelligent transport applications to alleviate the traffic problems like traffic jams and long trip times. The traffic flow in urban areas is more complicated than the traffic flow in highway, due to the slow movement of vehicles and crowded traffic flows in urban areas. In this paper, a vehicle detection and classification system at intersections is proposed. The system consists of three main phases: vehicle detection, vehicle tracking and vehicle classification. In the vehicle detection, the background subtraction is utilized to detect the moving vehicles by employing mixture of Gaussians (MoGs) algorithm, and then the removal shadow algorithm is developed to improve the detection phase and eliminate the undesired detected region (shadows). After the vehicle detection phase, the vehicles are tracked until they reach the classification line. Then the vehicle dimensions are utilized to classify the vehicles into three classes (cars, bikes, and trucks). In this system, there are three counters; one counter for each class. When the vehicle is classified to a specific class, the class counter is incremented by one. The counting results can be used to estimate the traffic density at intersections, and adjust the timing of traffic light for the next light cycle. The system is applied to videos obtained by stationary cameras. The results obtained demonstrate the robustness and accuracy of the proposed system.
Islanding detection in a distribution network with distributed generators using signal processing techniques
Authors: Kim Seong-Cheol , Ray Papia , Salkuti Surender Reddy
Published: September 2020

This paper proposes quick & accurate islanding detection technique for a distribution system with distributed generators (DGs). Here two schemes of islanding detection based on signal processing is proposed of which one is based on discrete wavelet transform (DWT) with artificial neural network (ANN), and another one is based on S-transform with ANN. The negative sequence current/voltage signals are retrieved at targeted DG location which are used for islanding detection in the distribution system. Here, the wavelet and S-transforms are used for fault location and classification applications. Further, the feature extraction is used for reducing the size of data matrix by transforming it into set of features. In this work, particle swarm optimization (PSO) based feature selection scheme is applied. Simulation results on test system indicate the efficacy of proposed islanding detection techniques.
Hybrid unified power quality conditioner for power quality enhancement
Authors: Djoudi Djellouli , Cherif Benoudjafer , Toufik Toumi , Abdelkhalek Othmane
Published: September 2020

In a low-voltage electrical network, harmonics, reactive power, the current and voltage imbalance, and voltage dips have harmful effects on electrical equipments. To overcome these problems, the hybrid UPQC is proposed. This paper discusses the structure of passive filters, parallel active filters, serial and combines (UPQC) to study the compensation of all types of disturbances likely to appear in the grid. Furthermore, the aim of reducing the size, cost of UPQC is to improve the quality of electric power, making it in compliance with the new regulatory constraints, we proposed the hybrid UPQC which uses passive filters and a combination of active filters. To validate the proposed topology, several sags of source voltage have been applied, at the point of common coupling (PCC). The simulation results from MATLAB/Simulink are discussed to verify the proposed topology.
A non-linear control method for active magnetic bearings with bounded input and output
Authors: Nguyen Danh Huy , Nguyen Lam Tung , Hoang Duc Chinh
Published: September 2020

Magnetic bearing is well-known for its advantage of reducing friction in rotary machines and is placing conventional bearings where high-speed operations and cleanliness are essential. It can be shown that the AM is a nonlinear system due to the relation between the magnetic force and current/rotor displacement. In this paper, a mathematical model of a 4-DOF AMB supported by four dual electric magnets is presented. The control objective is placed in a view of control input saturation and output limitation that are meaningful aspect in practical applications. Backstepping algorithm based control strategy is then adopted in order to achieve the high dynamic performance of the bearing. The control is designed in such a way that it takes input and output constraints into account by flexibly using hyperbolic tangent and barrier Lyapunov functions. Informative simulation studies are carried out to understand the operations of the machine and evaluate the controller quality.
PID optimal control to reduce energy consumption in DC-drive system
Authors: Maghfiroh Hari , Nizam Muhammad , Praptodiyono Supriyanto
Published: September 2020

The control system that is widely used in industry is PID (Proportional Integral Derivative). Almost 90% of industries still use PID control systems because of its simplicity, applicability, and reliability. However, the weakness of PID is that it takes a long time to tune. PID control with good performance and low energy consumption can be achieved using GA tuning with the appropriate objective function. The contribution of this paper is to propose the implementation of LQR control in the form of PID using GA tuning with LQR objective function. The proposed algorithm was implemented both in the simulation and hardware which is a mini conveyor with a DC motor. The result shows that the proposed algorithm is better in both IAE and energy consumption compared with other PID tuning, Ziegler–Nichols (ZN), and GA with IAE objective function. Compared with PID ZN, it has IAE and energy reduction by 2.76% and 16.07% respectively. Although its performance is lower than the LQR, it has other advantages that use fewer sensors. The other advantage of the proposed method is, PID is more familiar using. Therefore, it easy to be implemented in the existing system without a lot of changes.
Analysis on EMF characteristics for torque ripple reduction in BLAC motor intended for HVLS fan application
Authors: Abdullah Nurfaezah , Raja Othman Raja Nor Firdaus , Karim Kasrul Abdul , Tat Lim Seng
Published: September 2020

This paper analyzes the harmonic characteristics of electromagnetic force (EMF) in Brushless Alternating Current (BLAC) motor for High Volume Low Speed (HVLS) fan application. Vibration and noise are one of the main crucial things in HVLS fan application. It comes from torque ripples which can be detected by harmonics of Electro Magnetic Force (EMF). Commonly, there are a few methods to eliminate the noise and vibrations issue, but most literatures only focus on small motor and not intended for HVLS fan application. Thus, the objective of this paper is to eliminate the harmonics content in EMF at early stage design. Through EMF harmonics the expected torque produced could be used to select proper slot-pole number in order to eliminate the noise and vibrations issue. In here, the analysis involves three different slot-pole numbers which are 18s/20p, 12s/10p and 9s/8p BLAC model, respectively. All models have similar volume of permanent magnet. The analysis is carried out using FLUX 2D Finite Element Analysis (FEA) for EMF computational and transient torque computation. Later, Fast Fourier Transform (FFT) analysis is used to calculate the harmonics of EMF. The analysis stage includes the EMF parameter analysis, harmonics and torque ripples analysis. It was found that 18s/20p has higher output torque with the lowest 5% torque ripple value. As a conclusion, this paper presents low torque ripple in point of view of the EMF characteristics in designing HVLS fan.
Long Noncoding RNA LINC00261 Induces Chemosensitization to Tamoxifen in Human Breast Cancer
Authors: Shi Zhaoyan , Xiao Weidong , Hu Meifang
Published: September 2020

Breast cancer (BC) is one of the most prevalent and mortal malignancies in women worldwide, and tamoxifen is the mainstay treatment of breast cancer and the development of resistance represents a major obstacle for a cure. Long non-coding RNAs (LncRNAs) LINC00261 have been identified
to serve a key role in the development of several tumors. However, the role of LINC00261 in breast cancer and chemotherapy resistance remains largely unknown. To investigate the role of LINC00261 in BC cells, LINC00261 was upregulated in MCF-7-TAM cells by transfecting with LINC00261 plasmid
(pcDNA-LINCC00261). Subsequently, cell viability and drug sensitivity were measured using the CCK-8 assay. Reverse transcription-quantitative polymerase chain reaction (qRT-PCR) was performed to detect the level of LINC00261 in BC cells. Cell migration, invasion, and apoptosis were detected
by Transwell, Scratch Test and Flow cytometry, respectively. Additionally, the associated protein expression was detected using Western blot. The results demonstrated that LINC00261 was significantly down-regulated in BC cells, especially in MCF-7-TAM cells. Overexpression of LINC00261 inhibited
cell proliferation, migration, and invasion in MCF-7-TAM cells. Further, an abundant of LINC00261 sensitized breast cancer cells to tamoxifen and reduced tamoxifen-induced apoptosis in MCF-7-TAM cells. Finally, LINC00261 significantly regulated the protein expression of drug-resistant genes
and the protein expression related to tumor metastasis and cell apoptosis. Therefore, this study revealed that LINC00261 induces chemosensitization to tamoxifen in human breast cancer, it may be a useful biomarker and potential therapeutic target.
AB23A Reduces TGF-β1-Induced Human Cardiac Fibroblasts (HCF) Proliferation and Collagen Secretion via MER/ERK1/2/CREB Pathway
Authors: Hu Dinghui , Wu Yanhu , Du Jin , Li Hang , Liu Zuntao
Published: September 2020

Background and Objectives: Myocardial fibrosis is associated with many forms of heart diseases which is characterized by the accumulation of activated cardiac fibroblasts (CFBs) and excess deposition of extracellular matrix (ECM). Natural compounds such as Alisol B 23-acetate
has been proved to maintain the activation of ERK1/2, but whether it can affect cardiac fibroblasts by MER/ERK1/2/CREB signaling pathway is still unknown. Methods: The cell was identified with α-SMA protein level detected by immunofluorescence staining method. The cell
proliferation was examined by CCK8 assay. Col I and Col III protein levels were examined by western blot and sirius red staining to detect the ECM level. Furthermore, p-MERK, MERK, P-ERK, ERK and CREB were examined by western blot to verify whether Alisol could activate the MERK/ERK1/2/CREB
pathway in myocardial fibrosis. Results: CCK8 assay result indicated that Alisol reduced the cell viability of CFBs induced by TGF-β1. In addition, Alisol significantly decreased the ECM deposition of CFBs. Furthermore, Alisol could activate MERK/ERK1/2/CREB signaling pathway.
Conclusion: These results verified that Alisol inhibited myocardial fibrosis via MERK/ERK1/2/CREB pathway.
Finite Element Analysis of Cartilage Stress of Rabbits in the Knee Joints and Establishment of a Model for Cartilage Defects in Different Weight-Bearing Sites
Authors: Wei Tan Zhen , Bin-ang Wang , Jialei Chen , Xin Duan , Ming Liu , Zhou Xiang
Published: September 2020

New Zealand white rabbits have been widely used to establish cartilage defect models, but there has been less research on stress analysis of the knee joint, and even less in cartilage defect models at different weight-bearing sites. A biomechanical model of the upper zone was established
using finite element analysis. An animal model of cartilage defect was established to replicate minor trauma in different weight-bearing parts by simple surgery. The results showed that the stress in the posterior region of condyle was heavier than any weight-bearing areas, the stress in the
posterior part of condyle was intermediate, the stress in the trochlear region was the smallest. The cartilage can be exposed by prolonging the medial surgical incision and then cartilage defects can be formed. Finite element analysis is an effective technique to study the mechanical properties
of animal cartilage. Prolonging the medial incision can expose cartilage at different weight-bearing sites and establish a cartilage defect model.
Latent Membrane Protein 1 Antibody Inhibited Cell Stemness Growth of Nasopharyngeal Carcinoma by Regulating PI3K/AKT Signaling Pathway
Authors: Zhang Dawei , Xiong Lin , Li Liang , Chen Yuan , Tang Xiaojun , Tang Qi , Mao Yuan , Ming Hao , Chen Zhi , Du Yinjuan , Wang Yang , Chen Renjie , Zhu Jin
Published: September 2020

Objective: The aim of the study was to investigate the effects of LMP1-Fab antibody on Nasopharyngeal carcinoma (NPC) cancer stem cells (CSCs). Methods/Results: LMP1 was identified to play an important role in maintaining the stemness characteristics of NPC by sphere formation,
as is evidenced by CCK-8 and colony formation assays. Furthermore, CCK8 and TUNEL assays indicated that LMP1-Fab antibody could accelerate cell apoptosis while inhibiting cell proliferation in nasopharyngeal carcinoma stem cell. Notably, LMP1-Fab antibody inhibited NPC xenograft cancer growth
in the nude mice. At the molecular level, LMP1-Fab antibody inhibited the phosphorylation of PI3K/AKT signaling pathway both in vitro and in vivo. More importantly, these effects were blocked by PI3K/AKT phosphorylation inhibitor LY294002. Conclusion: These results suggested
that the novel antibody-targeting LMP1 is likely to be a promising strategy for the treatment of NPC.