The paper presents the special software for transient FE analysis of coupled electromagnetic-thermal problems in a squirrel cage submerged motor working at cryogenic temperature. A time-stepping finite element method and transients analysis of an induction motor has been applied. The non-linearity of the magnetic circuit, the movement of the rotor, skewed slots, and the influence of temperature on electric and thermal properties of the materials has been taken into account. Developed on the basis of presented algorithm a computer program used to analyze the phenomenon of current displacement in the rotor bars of high-voltage cage induction motor working in cryogenic conditions. The results of the simulations are presented.
As a consequence of recent implementations of EU Directives related to noise protection more and more students of various AGH-UST programs are introduced to the basics of acoustic measurements. Students at various levels of theoretical background in the field of acoustic measurements are offered practical training in measurements using digital sound analyzers. The situation would be optimal if each student could have a device at his/her own disposal. Unfortunately, such a situation is not possible at the moment because of various reasons. With the above problem in mind, a dedicated software package has been developed, implemented in the LabVIEW environment, which allows detailed studies of problems related to the acoustic signal measurement using sound level meters, as well as tasks in spectral analysis (1/1 and 1/3 band filters) and narrow-band (FFT) analysis. With such organization during the introductory laboratory classes each student is offered a direct individual contact with a virtual device that is properly pre-programmed for realization of a well-constructed learning process. It definitely facilitates understanding of the essence of acoustic signal measurements and provides a good basis for further laboratory work carried out as a team-activity.
An electronic system and an algorithm for estimating pedestrian geographic location in urban terrain is reported in the paper. Different sources of kinematic and positioning data are acquired (i.e.: accelerometer, gyroscope, GPS receiver, raster maps of terrain) and jointly processed by a Monte-Carlo simulation algorithm based on the particle filtering scheme. These data are processed and fused to estimate the most probable geographical location of the user. A prototype system was designed, built and tested with a view to aiding blind pedestrians. It was shown in the conducted field trials that the method yields superior results to sole GPS readouts. Moreover, the estimated location of the user can be effectively sustained when GPS fixes are not available (e.g. tunnels).
To evaluate the role of preovulatory progesterone on canine sexual behavior and the course of proestrus and estrus, seven bitches in spontaneous cycles were treated with aglepristone for temporary elimination of progesterone action. Aglepristone was administered at the dose 10 mg/kg b.m., two times 24 hours apart, beginning in early proestrus when progesterone concen- tration was <0.5 ng/ml. Seven untreated bitches served as a control group. Reproductive sexual behavior (standing behavior, display vulva, tail deviation) was evaluated according to behavioral score. Cytologic, clinical and vaginoscopic examinations and progesterone measurements were used for the determination of proestrus and estrus and estimation of ovulation time. Although, a similar pattern and magnitude of sexual behavior were observed in both groups, the duration of a total reproductive behavior was significantly extended (28.71 ± 2.06 vs 17.00 ± 2.45, p <0.05) in experimental group; similarly, the length of cytologic estrus (23.86 ± 3.02 vs 11.14 ± 2.41, p <0.05) was prolonged in treated bitches. In contrast, ovulation rate, duration of proestrus did not differ between the groups (p >0.05). We conclude, that during the canine estrus cycle the preovulatory progesterone terminates the duration of reproductive behavior and cytologic estrus.
There is no information available about the incidence of anestrus and its clinical forms after service in dairy cows in Poland. Thus, the aim of this study was to investigate the incidence of clinical forms of anoestrus after unsuccessful artificial insemination in dairy cows based on ultrasound examination. The study was carried out on 1543 Polish Holstein-Friesian cows in 8 dairy herds in north-east Poland over a three-year period. Cows were examined for pregnancy on day 35 after AI using a Honda 1500 portable ultrasound scanner equipped with a 5 MHz linear-array transducer. Cows diagnosed as pregnant were re-examined on day 45. Of the 1543 inseminated cows, 408 (26.4%) showed no estrus signs and were diagnosed not-pregnant by ultrasonography, 328 (21.3%) returned to estrus within 35 days, and 807 (52.3%) were pregnant via artificial insemination. The incidence of anestrus after service in non-pregnant cows varied among herds from 10.3% to 32.9% of cows (p<0.05). Based on ultrasound examination silent heat was diagnosed in 324 (79.4%), corpus luteum pseudograviditatis in 36 (8.8%), ovarian cysts in 26 (6.4%), and ovarian afunction in 22 (5.4%) of 408 anestrous, non-pregnant cows. The results of this study showed that the incidence of anestrus after service in dairy herds in North-East Poland was high. The most prevalent clinical form of post-service anestrus was silent heat.
Previous studies have compared the effectiveness of dinoprost and cloprostenol in cows yielding conflicting results. The aim of our study was to evaluate the efficacy of single treatment with cloprostenol or dinoprost on estrus and reproductive performance in cows with unobserved estrus after service. The study was conducted over four years in two dairy herds of Polish Holstein Frisian cows under a herd health program with an average milk yield per cow over 9000 L. Cows (n=523) diagnosed ultrasonographically as non-pregnant and with a corpus luteum were randomly assigned to be treated with either cloprostenol (n=261) or dinoprost (n=262). The estrus detection rates after administration of cloprostenol or dinoprost were 59.4%, and 57.6%, respectively. The difference between both groups was not statistically significant (p>0.05). Distribution of observed estrus did not differ between cloprostenol and dinoprost. There were no differences (p>0.05) between cloprostenol and dinoprost in conception rate (65.2% vs. 66.2%, respectively) and pregnancy rate (57.5% vs. 54.9%, respectively). Mean days open were similar in cows of both treatments (177.5 ± 74.6 days vs. 175.8 ± 62.6 days, respectively; p>0.05). In conclusion, data from this study showed no significant differences in estrus detection rates and fertility between cows with unobserved estrus after service treated with cloprostenol or dinoprost. Both products are equally useful for the treatment of non-pregnant dairy cows with anestrus after service within a reproductive herd health program.
In the paper, the mathematical model of coupled electromagnetic and thermal phenomena in the pulse transformer taking into account the magnetic hysteresis is presented. For the mapping of magnetic hysteresis, Jiles-Atherton model is applied. In order to solve field equations, the finite element method (FEM), "step-by-step" procedure and Newton-Raphson algorithm are used. Software elaborated on this basis is used for analysis of hysteresis loss in the core. Selected results of investigations are shown.
The paper presents an FE model of coupled electromagnetic and thermal phenomena in Line Start Permanent Magnet Synchronous Motors (LSPMSMs). An algorithm for solving equations of a discrete model using the FEM has been presented. On the basis of this algorithm the author’s personally developed software for the analysis of coupled electromagnetic-thermal phenomena in the LSPMS motors was elaborated. This software was used to analyze the start-up process of motors with identical stator and rotor magnetic circuits and different materials of the starting cage. The start-up process of motors with the squirrel-cage made of aluminum and copper was considered. The influence of temperature on the start-up process has been taken into account. The results of simulation tests were compared with the results of measurements.
The objective of this study was to evaluate the effect of a second prostaglandin F2α (PGF2α) treatment during Ovsynch on luteal regression and fertility in dairy cows, compared with standard Ovsynch. The study was conducted on 111 Holstein Friesian multiparous cows on commercial dairy farm. The cows in the experimental group (n=48) received two treatments of PGF2α 24 hours apart during Ovsynch. The cows in the control group (n=63) were synchronized with standard Ovsynch. To assess the progesterone (P4) concentration blood samples were collected at the day of PGF2α treatment and at the 2nd GnRH treatment. Pregnancy was evaluated by ultrasound examination 37-40 days after timed artificial insemination (TAI) by ultrasound. Cows diagnosed pregnant were re-examined between days 70-80 after TAI. The percentage of cows with complete corpus luteum (CL) regression (P4<0.5 ng/ml at the time of the 2nd GnRH treatment) was 89.6 % after two PGF2α treatments and 88.9 % after one PGF2α treatment. There were no statistically significant differences (p>0.05) in the pregnancies per artificial insemination (P/AI) between the experimental and control group (P/AI). However, the pregnancy loss rate was lower in cows receiving two PGF2α treatments than in the control animals (0.0 % vs. 6.4 %; p<0.05). In conclusion, the second PGF2α treatment during Ovsynch protocol had no significant effect on CL regression and P/AI in dairy cows. The pregnancy losses until days 75-80 after TAI were significantly lower after two PGF2α treatments than after one PGF2α treatment.
The aim of the study was to investigate the influence of cystic ovarian follicles (COFs) occurring after puerperium on fertility and the effect of their treatment with progesterone releasing device on reproductive performance in dairy cows. The study was carried out in 3 herds of Polish Holstein-Friesian cows under herd health program. COFs were diagnosed by ultrasound above 60 days p.p. They were defined as follicular structures with a diameter > 2.5 cm in the absence of a corpus luteum at two repeated examinations at the 14-days interval. On the day of COF diagnosis blood samples were collected to measure progesterone (P4) concentration. On the basis of the wall thickness measurement and progesterone concentration at the first examination, the COFs were differentiated into follicular and luteal cysts. The experimental group consisted of 23 animals with COF. The cows were treated with PRID Delta (Ceva Animal Health, Poland), containing 1.55 g of progesterone, for 7 days. The cows without oestrus signs within 14 days after treatment were re-examinated. If COF persisted, the cows were treated again with PRID Delta. The treatment was repeated maximum three times. Fifteen cows with ovarian cysts were left untreated and served as a control group. The cows with COF were matched to healthy cows without COF. The cows with COF had worse fertility performances compared to cows without COF. There were significant (p<0.05) differences in conception rates, number of services per conception and days open between these groups. Compared with non-treated cows with COF, in cows with COF treated with PRID Delta conceptions rates and number of services per conception were similar, but the days open were significantly (p<0.05) lower in cows treated than in non-treated (183.3 days vs. 277.6 days). There were no differences in reproductive performances between the follicular and luteal cysts in treated and non-treated cows. In conclusion, the results of our study confirm the negative impact of COF after puerperium on fertility in dairy cows. Furthermore the results indicate the usefulness of PRID Delta for the treatment of COF occurring after the puerperium regardless of cysts type.