Search

The paper presents two fuzzy logic control algorithms: type-1 and type-2. These two nonlinear techniques are used for adjust the speed control with a direct stator flux orientation control of a doubly fed induction motor. The effectiveness of the proposed control strategy is evaluated under different operating conditions such as of reference speed and for load torque step changes at nominal parameters and in the presence of parameter variation (stator resistance, rotor resistance and moment of inertia). The results of the simulation of the doubly fed induction motor velocity control have shown that fuzzy type-2 ensures better dynamic performances with respect to fuzzy type-1 control, even by parametric variations and external disturbances.

In this paper, a new control stra¬tegy is deve¬loped; an adaptive fuzzy controller based on Lyapunov's stability theory (AFLC) recalculates the real-time PI-fuzzy gains and combines the advantages of two robust techniques i.e. the fuzzy logic control and the adaptive one. For the new adaptive fuzzy control, we followed two steps: in the first one, a PI-fuzzy controller is designed, in the second step, the gains of a fuzzy regulator are determined. Extensive simulation results are presented to validate the proposed technique. The system is tested at different speeds and a very satisfactory performance has been achieved.

A new concept for reducing the losses in a boost converter is described. With the help of an auxiliary switch and a resonant circuit, zero-voltage switching at turn-off and zero-current switching during turn-on are achieved. The modes of the circuit are shown in detail. The energy recovery of the turn-off is analyzed and the recovered energy is calculated; an optimized switching concept therefore is described. The influence of the parasitic capacity of the switch is discussed. Dimensioning hints for the converter and the design of the recuperation circuit are given. A bread-boarded design shows the functional efficiency of the concept.

A solar electric vehicle (SEV) is an electric vehicle (EV) with onboard photovoltaic cells charging a set of batteries for extended driving range. This study aimed to improve the energy management system of a SEV, called YILDIZ, using a fuzzy logic control system (FLC). A MATLAB based simulation model of three basic components of a solar car: solar cell modules, batteries and motor drive system was performed. An original FLC was developed. For proving its applicability, the performances of the SEV were tested by simulation, in accordance with the standard test drive cycle ECE-15. The characteristics obtained with the original Proportional Integral Fuzzy Logic Control (PI-FLC) were compared with those obtained with a classical Proportional Integral (PI) controller. Using the designed model, we calculated the range of YILDIZ with and without PV feeding which gave us an opportunity to study and compare both SEV and EV models on real race-track situation. Then the optimum speed, at any time, which enabled the vehicle to reach a chosen destination as quickly as possible, while fully using the available energy, was calculated. Proposed solutions tested on YILDIZ. Results of simulations were compared with YILDIZ run on the Formula-G race track in Izmit, Turkey.

The paper presents the original SV-100 platform that enables low-cost and very high accuracy determinations of noise and vibration levels. The aim of the proposed platform is to achieve an effective integration of the two topics of this analysis: vibrations and noises. To the best of our knowledge, no low price, dedicated compact platform with embedded measuring instruments exists. For proving the practical utility of the proposed platform, two induction motors of 7.5 kW and 11 kW, respectively, in single-layer winding, at 1000 rpm, with IE3 premium efficiency were analyzed. This analysis is required because, according to IEC60034-30 standard, the IE3 efficiency standard has become mandatory for induction motors of rated power greater than 7.5 kW. Therefore, in order to improve the motor operating efficiency, the power losses caused by noises and vibrations have to be reduced. Several variants of supply were studied, i.e., by the three-phase 50 Hz network and by a three-phase inverter at 40, 50 and 60 Hz, respectively. The experimental determinations of noises are presented comparatively, by using a Bruel&Kjaer sonometer and by using the new platform SV-100. The results are compared with the IEC60034 standard.

An experimental exploration of using an Electro�nically Controlled Capacitor (ECC) in the supply system of a two speed single phase induction motor drive is presented. The ECC solution and the method with solution with a fixed value capacitor are comparatively analyzed in terms of efficiency and maximum torque availability. The losses and the over-voltages due to the electronic commutation are also analyzed. The paper proves the feasibility of the ECC solution and underlines its advantages and drawbacks. The optimal value of the switching frequency of ECC has been experimentally determined.

Circulating fluidized bed boilers are increasingly used in the power generation due to their higher combustion efficiency and lower pollutant emissions. Such boilers require an effective control of the bed temperature, because it influences the boiler combustion efficiency and the rate of harmful emissions. A Particle-Swarm-Optimization-Proportional-Integrative-Derivative (PSO-PID) controller for the bed temperature of a circulating fluidized bed boiler is presented. In order to prove the capability of the proposed controller, its performances are compared at different boiler loads with those of a Fuzzy Logic (FL) controller. The simulation results demonstrate some advantages of the proposed controller.

The value of the immunohistochemistry (IHC) method used in the differential diagnosis of primary tumors and metastatic tumors with unknown primary was estimated. From 323 cases where IHC was performed, in 254 cases it was used for target therapy selection in breast cancer patients. GIST was confirmed in 73 cases. From 96 cases of various biopsy and surgical excision samples, 23 cases of retroperitoneal tumor masses were studied detail. In 12 cases, tumors were primary and in 11 cases, there were retroperitoneal lymphadenopathies with unknown primary. The value of certain monoclonal antibodies positivity for exact diagnosis was estimated. In conclusion, we consider that IHC is an important investigation method for the differential diagnosis of tumors with unknown origin. [ABSTRACT FROM AUTHOR]

Urinary tract infections (UTI) of sows (characterized by ascending infections of the urinary bladder (cyst), ureters, and renal pelvis), are major health issues with a significant economic impact to the swine industry. The current detection of UTI incidents lacks sensitivity; thus, UTIs remain largely under-diagnosed. The value of metabolomics in unraveling the mechanisms of sow UTI has not yet been established. This study aims to investigate the urine metabolome of sows for UTI biomarkers. Urine samples were collected from 58 culled sows from a farrow-to-finish herd in Greece. Urine metabolomic profiles in 31 healthy controls and in 27 inflammatory ones were evaluated. UHPLC-qTOF MS/MS was applied for the analysis with a combination of multivariate and univariate statistical analysis. Eighteen potential markers were found. The changes in several urine metabolites classes (nucleosides, indoles, isoflavones, and dipeptides), as well as amino-acids allowed for an adequate discrimination between the study groups. Identified metabolites were involved in purine metabolism; phenylalanine; tyrosine and tryptophan biosynthesis; and phenylalanine metabolism. Through ROC analysis it was shown that the 18 identified metabolite biomarkers exhibited good predictive accuracy. In summary, our study provided new information on the potential targets for predicting early and accurate diagnosis of UTI. Further, this information also sheds light on how it could be applied in live animals.

The objective of the present study was to investigate the mechanical indices of hoof horn and their association with length measurements and lesion score. The feet of 185 culled sows from three Greek farms (A: 57 sows; B: 64 sows; C: 64 sows) were used. A slice from the dorsal wall of each claw was used to assess by a three-point bending test the Young's modulus, yield stress and aximum stress values. The available data from a companion study (part 1) on the length measurements and lesion scores of the claws were used to reveal possible relationships. The Young's modulus values were significantly higher ( p < 0.001 or p < 0.01 depending on location of claw) in the sows of farm C compared to those in sows of farms A and B and in sows of farm B compared to those in the sows of farm A. Yield and maximum stress values were significantly higher ( p < 0.05 or p < 0.001 depending on the location of the claw) in the sows of farm C compared to those in the sows of farm A and in the sows of farm B compared to those in the sows of farm A. An increase in heel-sole length decreased all mechanical indices. Young's modulus and yield stress were associated with wall lesion severity while maximum stress with wall and heel lesion severity. Overall, we conclude that mechanical efficiency deteriorates as length and lesion score increases.

The aim of the study was to investigate variations in lengths and lesions in claws of culled sows and to evaluate their association. All four feet of 185 sows from three Greek farrow-to-finish farms (Farm A: 57 sows; Farm B: 64 sows; Farm C: 64 sows) were examined for lesions and their lengths were measured. All claw lengths were lower in sows of farm C compared to those from sows of B and A. Claw lengths in sows of farm B were lower compared to those from A for all lateral toes of front feet and for all medial and four out of three lateral toes of rear feet. Sum of length measurements of the main toes of the front feet (SLF) associated with lesions on sole, white line and heel of front feet, while sum of length measurements of the main toes of the rear feet (SLR) associated with all lesions of the rear feet. The lengths of the main toes were correlated with the length of dew claws on front and rear feet. Overall, sows' claw lesion severity and claw lengths may differ between farms and frequency of lesions is higher in longer claws.

Background: Urinary tract infections (UTI) of sows characterized by cystitis, which may progress to ureteritis and pyelonephritis, can affect their productivity, longevity and welfare. In this study, we determined the prevalence of UTI by histopathology and bacteriology. Furthermore, we investigated possible associations between histologically confirmed cystitis and the results of urinalysis and urine cultures in culled sows from three farrow-to-finish herds in Greece., Materials and Methods: One hundred eighty-five routinely culled sows were included in the study. Their urinary bladder was collected from abattoirs and subjected to histopathology. Furthermore, urinalysis and urine cultures were performed on urine samples aseptically collected from the bladders., Results: Histologically confirmed cystitis was evident in 85/185 (45.94%) culled sows. Among those, 44 (51.76%) suffered from acute and 41 (48.24%) from chronic inflammation. The majority of positive urine cultures were due to colonization of the urinary tract with E.coli, which accounted for 55.81% of the total cases, followed by Staphylococcus spp. which accounted for 18.60% of detected infections. Evidence of cystitis was associated with bacteriuria and sows with bacteriuria were 2.30 (P = 0.03, 95% CI: 1.10-4.83) times more likely to have histologically confirmed cystitis compared to sows with negative urine cultures. Bacteriuria was associated with proteinuria (P < 0.01, OR = 9.72, 2.63-35.88), increased urine pH (P < 0.01, 3.40, 1.10-10.56) and presence of sediment (P < 0.01, 6.00, 1.50-23.76) in urine. Sows with proteinuria had 9.72 (P < 0.01, 2.63-35.88) times higher odds of bacteriuria than those without. Histologically defined cystitis was associated with proteinuria (P < 0.01, 2.03-13.20) and decreased urine pH (P < 0.01, 0.13-0.72). Sows with proteinuria were 5.18 (P < 0.01, 2.03-13.2) times more likely to have histological lesions consistent with cystitis, than those without. For one unit increase in pH, it was 3.20 (P = 0.006, 1.39-7.69) times less likely for a sow to have chronic or acute cystitis compared to absence of cystitis., Conclusion: In the studied population, UTI affected almost one out of two culled sows. Bacteriuria, which was more common among sows with UTI than those without, was mainly ascribed to members of the intestinal and environmental bacteria. Proteinuria and the existence of urine sediment which were associated with UTI, could be used as proxy traits for UTI in live sows.

Background: Gastrointestinal stromal tumors (GISTs) are low-grade malignant tumors that may arise anywhere in the alimentary tract, and in the past, most of them were diagnosed as intestinal leiomyoma or leiomyosarcoma. GISTs of the duodenum make up only 4.5% of all GISTs., Materials and Methods: We report a patient presented with upper GI bleeding who exhibited radiological findings of a tumor in the third portion of the duodenum. The patient underwent a segmental duodenectomy. Pathological examination concluded in a GIST., Results: The patient is free of recurrence for one year after surgery., Conclusions: Our case report, along with other, highlights that surgical resection remains the cornerstone of treatment for patients with localized disease. Along with others, we agree that from oncologic point of view, partial resection of the duodenum is an alternative to a duodenopancreatectomy.

By inducing experimental ulcers in the rabbit with the type 1 Herpes simplex strain, isolated from the herpes vesicles from a vagotomized patient, the authors demonstrate the protective role of vagotomy, the ulcerogenic capacity of the virus, which can be considered as an etiological factor of human gastroduodenal ulceration. They also discuss the possibilities for a new medical therapy of this disturbance.