Microwave interferometric technique for characterizing few mode fibers

We propose and experimentally demonstrate a simple and accurate technique for measuring differential mode group delay (DMGD) in few mode fibers (FMF). A frequency-swept microwave signal is modulated on a filtered optical incoherent source. The microwave signals carried on different fiber modes experience different time delays and interfere with each other in the photodetector. Optical interference between propagating fiber modes is avoided by the use of an incoherent optical source. A mathematical model is established to analyze the interference pattern and extract the DMGD values. A 456-m two-mode fiber and a 981-m FMF, which supports four LP modes, are measured. The measurement covers the whole C-band and the results coincide well with those obtained by the time-of-flight method and the numerical simulations. A precision of ±0.002 ps/m is achieved.

Secagem e armazenamento de sementes de juçara

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A simplified method for determining the high frequency induction motor equivalent electrical circuit parameters to be used in EMI effect

The aim of this paper is to present a simple method for determining the high frequency parameters of a three-phase induction motor to be used in studies involving variable speed drives with PWM three-phase inverters, in which it is necessary to check the effects caused to the motor by the electromagnetic interference, (EMI) in the differential mode, as well as in the common mode. The motor parameters determination is generally performed in adequate laboratories using accurate instruments, such as very expensive RLC bridges. The method proposed here consists in the identification of the motor equivalent electrical circuit parameters in rated frequency and in high frequency through characteristic tests in the laboratory, together with the use of characteristic equations and curves, shown in the references to be mentioned for determining the motor high frequency parasite capacitances and also through system simulations using dedicated software, like Pspice, determining the characteristic waveforms involved in the differential and common mode phenomena, comparing and validating the procedure through published papers [01].

Kinetic asymmetry in the gel-liquid crystalline state transitions of DDAB vesicles studied by differential scanning calorimetry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Measurement of inclusive differential cross sections for Upsilon(1S) production in p(p)over-bar collisions at root s=1.96 TeV

We present measurements of the inclusive production cross sections of the Upsilon(1S) bottomonium state in p (p) over bar collisions at root s=1.96 TeV. Using the Upsilon(1S)->mu(+)mu(-) decay mode for a data sample of 159 +/- 10 pb(-1) collected by the D0 detector at the Fermilab Tevatron collider, we determine the differential cross sections as a function of the Upsilon(1S) transverse momentum for three ranges of the Upsilon(1S) rapidity: 0 <\y(Upsilon)\<= 0.6, 0.6 <\y(Upsilon)\<= 1.2, and 1.2 <\y(Upsilon)\<= 1.8.

B-mode Ultrasound and Doppler Mode for Early-stage Pregnancy Diagnosis in Shi-Tzu Bitches

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Histopathological and b-mode ultrasound characteristics in a primary canine duodenal adenocarcinoma - case report

Lower gastrointestinal tract neoplasms are rare in domestic animals, representing 3% of all biopsies and necropsies. Our objective is to describe the histopathological and B-mode ultrasound findings in a case of duodenal adenocarcinoma in a dog, since it commonly occurs in the large intestine. On ultrasound examination, there was transmural wall thickening in the duodenum with loss of layer structure, focal peritonitis and adenopathy. Histopathological examination of the intestinal mass revealed a malignant epithelial neoplasm, densely cellular and infiltrative, extending through the lamina propria, submucosa, muscle and hypodermis, characterizing a duodenal adenocarcinoma. We conclude that adenocarcinomas may be included in the differential diagnosis of transmural lesions in the duodenum in B-mode ultrasound examinations, but a laparotomy and biopsy are required for definitive diagnosis.