55 research outputs found
PFC Control for LED Lamp Driver Using Sensorless Predictive Current Controller
Light-emitting diodes (LEDs) have recently become of utmost significance to replace conventional lighting sources. Power factor correction (PFC) control of LED lamps requires three sensors which cause more cost, increase time delay, and increase noise, thus reducing drive reliability. Alternative methods to estimate the inductor current instead of its measurement are mandatory. This paper proposes a sensorless predictive current controller to enhance power factor (PF) of LED lamp driver and reduce driver cost. The inductor current is estimated instead of employing current sensor relying on measured input and output voltages. Zero-crossing detector is utilized to accomplish robust performance during distorted supply voltage. The controller and power circuit are isolated. The control algorithm employs a two-loop control to achieve a high PF with sinusoidal input current. Rapid speed performance is accomplished. The influences of PFC on input current value, PF and harmonic orders are presented. A prototype LED lamp driver with the suggested PFC structure is tested practically by a digital signal processor (DSP) DS1104 platform to validate its effectiveness. Experimental tests under various working conditions are provided to prove the usefulness of the suggested PFC control
Rehabilitation Of Ex-Mining Pond And Existing Wetland For Integrated Stormwater Management.
A study on rehabilitation of ex-mining pond and existing wetland for integrated storm water facilities has been carried out in Malaysia
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Functional signatures of evolutionarily young CTCF binding sites
Abstract: Background: The introduction of novel CTCF binding sites in gene regulatory regions in the rodent lineage is partly the effect of transposable element expansion, particularly in the murine lineage. The exact mechanism and functional impact of evolutionarily novel CTCF binding sites are not yet fully understood. We investigated the impact of novel subspecies-specific CTCF binding sites in two Mus genus subspecies, Mus musculus domesticus and Mus musculus castaneus, that diverged 0.5 million years ago. Results: CTCF binding site evolution is influenced by the action of the B2-B4 family of transposable elements independently in both lineages, leading to the proliferation of novel CTCF binding sites. A subset of evolutionarily young sites may harbour transcriptional functionality as evidenced by the stability of their binding across multiple tissues in M. musculus domesticus (BL6), while overall the distance of subspecies-specific CTCF binding to the nearest transcription start sites and/or topologically associated domains (TADs) is largely similar to musculus-common CTCF sites. Remarkably, we discovered a recurrent regulatory architecture consisting of a CTCF binding site and an interferon gene that appears to have been tandemly duplicated to create a 15-gene cluster on chromosome 4, thus forming a novel BL6 specific immune locus in which CTCF may play a regulatory role. Conclusions: Our results demonstrate that thousands of CTCF binding sites show multiple functional signatures rapidly after incorporation into the genome
Prevalence of <em>Brucella</em> spp. in milk from aborted and non-aborted animals in Dhamar governorate, Yemen
Brucella infection in animals is considered a great problem in most countries of the world. Our study designed to determine the prevalence of brucella in field animal’s milk in Dhamar governorate, Yemen. Total of 808 raw milk samples from non-aborted field animals, 120 milk samples from aborted animals, and 30 pasteurized milk samples were teste by Milk-Ring Test (MRT), milk-ELISA test, isolation and identification of brucella species, and antibiotic susceptibility. The prevalence of brucella in milk samples from field animals was 0.8%, 2.6%, and 2% in cows, sheep, and goat milk samples respectively with MRT, and 0.8%, 1.3% and 1.6% in cows, sheep and goat milk samples respectively with the milk- ELISA test. The prevalence rate in milk samples from aborted animals was 33%, 64% and 41.2% with the MRT and 39%, 49%, and 41.2% in cows, sheep and goats respectively with the milk-ELISA test. All pasteurized milk samples were negative for the milk-ELISA test. The result of isolation showed 0.1% of Brucella in milk samples from field animals while 9.2% from aborted animals. All isolates of Brucella species were sensitivities to rifampicin, doxycycline, kanamycin, gentamicin, streptomycin, tetracycline, and ciprofloxacin, while resistant to ampicillin, erythromycin, and novobiocin. In conclusion, the high prevalence of milk brucella especially in aborted animals needs focusing and build controlling strategies plans to decrease the losses to the economy and avoid transferred to humans with unpasteurized milk consumption
Sex-Based Disparities in Acute Myocardial Infarction Treatment Patterns and Outcomes in Older Adults Hospitalized Across 6 High-Income Countries: An Analysis From the International Health Systems Research Collaborative
BACKGROUND: Sex differences in acute myocardial infarction treatment and outcomes are well documented, but it is unclear whether differences are consistent across countries. The objective of this study was to investigate the epidemiology, use of interventional procedures, and outcomes for older females and males hospitalized with ST-segment-elevation myocardial infarction (STEMI) and non-ST-segment-elevation myocardial infarction (NSTEMI) in 6 diverse countries. METHODS: We conducted a serial cross-sectional cohort study of 1 508 205 adults aged ≥66 years hospitalized with STEMI and NSTEMI between 2011 and 2018 in the United States, Canada, England, the Netherlands, Taiwan, and Israel using administrative data. We compared females and males within each country with respect to age-standardized hospitalization rates, rates of cardiac catheterization, percutaneous coronary intervention, and coronary artery bypass graft surgery within 90 days of hospitalization, and 30-day age- and comorbidity-adjusted mortality. RESULTS: Hospitalization rates for STEMI and NSTEMI decreased between 2011 and 2018 in all countries, although the hospitalization rate ratio (rate in males/rate in females) increased in virtually all countries (eg, US STEMI ratio, 1.58:1 in 2011 and 1.73:1 in 2018; Israel NSTEMI ratio, 1.71:1 in 2011 and 2.11:1 in 2018). Rates of cardiac catheterization, percutaneous coronary intervention, and coronary artery bypass graft surgery were lower for females than males for STEMI in all countries and years (eg, US cardiac catheterization in 2018, 88.6% for females versus 91.5% for males; Israel percutaneous coronary intervention in 2018, 76.7% for females versus 84.8% for males) with similar findings for NSTEMI. Adjusted mortality for STEMI in 2018 was higher for females than males in 5 countries (the United States, Canada, the Netherlands, Israel, and Taiwan) but lower for females than males in 5 countries for NSTEMI. CONCLUSIONS: We observed a larger decline in acute myocardial infarction hospitalizations for females than males between 2011 and 2018. Females were less likely to receive cardiac interventions and had higher mortality after STEMI. Sex disparities seem to transcend borders, raising questions about the underlying causes and remedies
Two-Degrees of Freedom and Variable Structure Controllers for Induction Motor Drives
This paper presents a two-degrees-of-Freedom (2DOF) and variable structure control (VSC) schemes
for induction motor (IM) drives. The designed VSC incorporates independent feedback and
feedforward terms as 2DOF control principle. This structure improves the response of the
proposed VSC under speed reference tracking and load disturbance changes. Stability of
VSC using Lyapunov theory is discussed. Due to the variable nature of the switching function
of VSC, two conditions to ensure Lyapunov stability candidate are derived based on the error
signal. A design criterion for the parameters of VSC are introduced to guarantee the stability.
The complete IM drive system with the proposed VSC controller is built using MATLAB/Simulink.
A laboratory prototype is executed experimentally using DSP-DS1104 control board. All
controllers are implemented practically. Simulation and experimental results are provided
under different working conditions. Performance evaluation of classic control schemes and
the proposed VSC approach is presented. The proposed VSC approach gives superior behavior
under speed reference variations and torque disturbances. The disturbances using the proposed
controller are strongly suppressed compared to classic 2DOF control scheme
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