322,901 research outputs found
Vector Model for Losses in Non-Oriented Steel sheets
No full textThe presence of two-dimensional (2D) magnetization processes in devices and electrical machines calls for the development of vector model for loss prediction. Starting from the Del Vecchio-Charap work [2], we developed a static model able to reproduce the 2D evolution of magnetization in soft non-oriented steel sheets: the most interesting case for applications.
The material is assimilated to an ensemble of biaxial grains, each associated with a hysteron having two orthogonal easy axes. In each of them, the field driven irreversible switch of magnetization between the easy directions (Barkhausen jump: BJ) is governed by the value of local coercive field (about ten times smaller than the anisotropy fields); the ensemble of all these BJs accounts for the domain wall displacement. After the BJ, the local magnetization is brought to its energy minimum by the antagonism between anisotropy and Zeeman energy, so determining the reversible magnetization component. Domain wall reversible processes (bending) are not considered, whereas the role of macroscopic and internal demagnetizing fields is accounted for.
The system average magnetization is obtained after integrating the outputs of single hysterons, each weighted by probability density functions suitably characterizing the material properties (i.e.: grain orientations, coercive and anisotropy fields). We have been able to reproduce the loss vs. polarization W(Jp) evolution in several non-oriented materials, subjected to alternating and rotating fields. In particular, under circular induction, the W drop at high Jp was always found, without introducing “ad hoc” fitting functions. It is remarkable that the outlined approach can be extended to systems magnetized in dynamic conditions.
[1] C. Appino, C. Ragusa, and F. Fiorillo, “Can rotational magnetization be theoretically assessd?”, IJAEM 44 (20144), 355-370
[2] R.M. Del Vecchio, S. H. Charap, “Two dimensional hysteresis model”, IEEE Trans. Mag. 20 (1984), 1437-143
Variazioni istologiche ed istochimoche dell’endometrio di bovine affette da corpo luteo persistente e trattate con PgF2 .
No full textPriapism in a castrated cat associated with feline infectious peritonitis
No full textThis report describes a case of feline infectious peritonitis (FIP) in a castrated cat which first presented with the unusual sign of priapism. Laboratory examinations showed increased serum protein content and decreased albumin/globulin ratio. Serum electrophoresis revealed increased α2- and γ-globulin content. One month after the first examination, the cat died. At necropsy, histopathological evaluation of organs showed inflammatory granulomatous lesions compatible with non-effusive FIP and coronavirus-specific polymerase chain reaction confirmed the diagnosis. FIP antigen was demonstrated immunohistochemically in penile tissue
Priapism in a castrated cat associated with feline infectious peritonitis
No full textThis report describes a case of feline infectious peritonitis (FIP) in a castrated cat which first presented with the unusual sign of priapism. Laboratory examinations showed increased serum protein content and decreased albumin/globulin ratio. Serum electrophoresis revealed increased α2- and γ-globulin content. One month after the first examination, the cat died. At necropsy, histopathological evaluation of organs showed inflammatory granulomatous lesions compatible with non-effusive FIP and coronavirus-specific polymerase chain reaction confirmed the diagnosis. FIP antigen was demonstrated immunohistochemically in penile tissue
VALUTAZIONE DELLA PRESENZA DI CHLAMYDOPHILA ABORTUS IN TAMPONI VAGINALI DI DONNE AFFETTE DA PROBLEMI D’INFERTILITÀ
No full textSevere tail defects in the spermatozoa ejaculated by an English bulldog.
No full textThis paper describes the case of a 2-year-old English Bulldog with severe teratozoospermia that consisted mainly of "Dag-like" defects, which is strong coiling of the tail. Although libido, semen volume and sperm concentration were normal, sperm motility was 5.0%, and 93.3% of spermatozoa exhibited morphological abnormalities affecting the tail. Transmission electron microscopic examination of the spermatozoa revealed strong folding, coiling and fracture of sperm midpieces and tails, axonemal defects and the presence of swollen and unevenly distributed mitochondria. Taking into account the dog's history and examinations and the constantly high percentage of abnormal spermatozoa over time, the defect was considered to be genetic in origin
An intercomparison of rotational loss measurements in non-oriented Fe-Si alloys
No full textWe report a comparison of rotational energy loss measurements in the same non-oriented Fe–Si laminations carried out by two
laboratories Istituto Nazionale di Ricerca Metrologica (INRiM) in Torino, Italy and Wolfson Centre for Magnetics (WCM) in Cardiff,
United Kingdom. The measurements were performed on disk samples at magnetizing frequencies between 5 and 200 Hz with controlled
circular flux density loci ranging between 0.2 and 1.9 T. Energy loss was measured applying both the fieldmetric and the rate-of-rise of
temperature methods. The latter, exploiting the rate of rise of temperature under quasi-adiabatic conditions, is conveniently adopted on
approaching magnetic saturation. Results from the two laboratories agree well up to 1.4 T, despite the different physical principles of the
fieldmetric vs. rate-of-rise of temperature methods and the different size of sample and measuring areas. The rate-of-rise of temperature
method seems to be the natural approach at high induction values
Evidenziazione di Chlamydia psittaci da organi bovini e membrane fetali abortite mediante reazione a catena della polimerasi (PCR)
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