Diseases and Causes of Death in European Bats: Dynamics in Disease Susceptibility and Infection Rates

Bats receive increasing attention in infectious disease studies, because of their well recognized status as reservoir species for various infectious agents. This is even more important, as bats with their capability of long distance dispersal and complex social structures are unique in the way microbes could be spread by these mammalian species. Nevertheless, infection studies in bats are predominantly limited to the identification of specific pathogens presenting a potential health threat to humans. But the impact of infectious agents on the individual host and their importance on bat mortality is largely unknown and has been neglected in most studies published to date.) were collected in different geographic regions in Germany. Most animals represented individual cases that have been incidentally found close to roosting sites or near human habitation in urban and urban-like environments. The bat carcasses were subjected to a post-mortem examination and investigated histo-pathologically, bacteriologically and virologically. Trauma and disease represented the most important causes of death in these bats. Comparative analysis of pathological findings and microbiological results show that microbial agents indeed have an impact on bats succumbing to infectious diseases, with fatal bacterial, viral and parasitic infections found in at least 12% of the bats investigated.Our data demonstrate the importance of diseases and infectious agents as cause of death in European bat species. The clear seasonal and individual variations in disease prevalence and infection rates indicate that maternity colonies are more susceptible to infectious agents, underlining the possible important role of host physiology, immunity and roosting behavior as risk factors for infection of bats

Model matematyczny silnika uniwersalnego zasilanego poprzez triak przy wykorzystaniu zespolonych szeregów fouriera

The present contribution shows an analytical method of the calculus of the torque ripple and current waveforms of a universal motor supplied by a triac directly from the network. The triac output voltage waveform is formulated by the complex Fourier series. The armature reaction of the motor is included in the calculus. The motor performance is computed using the circuit parameters determined by measurements. The calculated current waveforms are compared with the measured ones

Model matematyczny silnika uniwersalnego zasilanego poprzez tranzystor IGBT przy wykorzystaniu zespolonych szeregów Fouriera

The present contribution shows an analytical method of the calculus of the torque ripple and current waveforms of a universal motor supplied by an IGBT chopper. The chopper output voltage waveform is formulated by the Fourier series. The armature reaction of the motor is included in the calculus. The motor performance is computed using the circuit parameters determined by measurements. The calculated current waveforms are compared with the measured ones

EMC of universal DC motor

This document deals with electromagnetic compatibility (EMC) of universal motor operating at AC and DC power supply. Universal motors are used in a variety of applications and can be operated either at AC or DC supply current. The advantages of universal motors are especially high starting torque, very compact design and high running speeds. The drawback consists in the fact that the commutator and arcing brushes create electromagnetic interference (EMI), ozone and noise. This paper presents the results of oscilloscopic measurement of disturbing magnetic field in proximity of a universal motor at various speeds at AC and DC operation mode. The time derivation of the magnetic flux density is converted by an inductive coil to a voltage to be observed by oscilloscope

DC drive for universal motor

Universal motors are usually operated in AC mode and are controlled by means of triacs. This conventional solution is characterized by a cheap control hardware. On the other hand, it has some drawbacks. In particular the high peak to peak current gives poor motor efficiency and the consequential high brush temperature leads to limited motor lifetime. Significant improvements are obtained when using a more exacting converter. This paper presents the results obtained by using a diode rectifier and PWM controlled IGBT chopper. The RMS and peak-to-peak current of the motor are reduced, as well as electric losses and brush temperature. In addition, this operation mode enables increasing the motor output power or the motor lifetime. In order to reduce switching losses and electromagnetic interference of the converter, the assumed switching frequency is not higher than 1000 Hz

Sterowanie dwufazowego silnika indukcyjnego za pomocą konwencjonalnego trójfazowego falownika mostkowego

This paper describes the control of two-phase induction motor using a conventional three-phase bridge inverter. Two-phase induction motors in comparison with conventional three phase motors have the advantage of a simple stator current vector control. The physical phase currents themselves represent the coordinates of the stator current vector. For this reason two-phase induction motors are ideal for educational purposes as well as for experiments verifying various control strategies (for example sensorless speed control). The inherently best inverter topology for a two-phase induction motor consists of two single-phase bridge inverters. However, using a conventional three-phase bridge inverter may be an interesting alternative described in this paper.W artykule omówiono algorytm do obliczeń elektromagnetycznych silników synchronicznych z magnesami trwałymi o cewkach skupionych dla stanu pracy synchronicznej ustalonej. Algorytm bazuje na obliczeniu przebiegów czasowych strumieni skojarzonych z poszczególnymi fazami uzwojenia i napięć indukowanych w uzwojeniach oraz przebiegu czasowego momentu elektromagnetycznego w szczelinie powietrznej silnika. W tym celu wykorzystywana jest magnetostatyczna, dwuwymiarowa analiza rozkładu pola elektromagnetycznego w silniku metodą elementów skończonych (MES). W modelu MES silnika pozycja kątowa wirnika względem stojana ulega krokowej zmianie i dla każdej z pozycji siatka elementów skończonych jest odpowiednio modyfikowana. W artykule zaprezentowano przykładowe wyniki obliczeń dla 6-biegunowego silnika o cewkach skupionych i liczbie żłobków na biegun i fazę q=0.5. Uzyskane z pomocą nowego algorytmu wyniki obliczeń porównano z wynikami otrzymanymi z zastosowaniem oprogramowania komercyjnego, w którym wykorzystano tzw. analizę MES dla stanów przejściowych. Opracowany autorski algorytm obliczeniowy jest wykorzystywany do obliczania charakterystyk elektromechanicznych silników PMSM i CW-PMSM

Figure 2 from: Kaňuch P, Dorková M, Mikhailenko AP, Polumordvinov OA, Jarčuška B, Krištín A (2017) Isolated populations of the bush-cricket Pholidoptera frivaldszkyi (Orthoptera, Tettigoniidae) in Russia suggest a disjunct area of the species distribution. ZooKeys 665: 85-92. https://doi.org/10.3897/zookeys.665.12339

Figure 2 - Maximum-likelihood (ML) phylogenetic tree for 16 haplotypes of Pholidoptera frivaldszkyi (pf1–pf16; GenBank accession numbers KF706416–KF706428, KY554960–KY554962) with outgroup species (KC852400, KY554963–KY554966) based on a 778 bp fragment of the mtDNA COI gene. Tree topology and branch lengths of Bayesian inference were congruent with ML analysis. Nodes with significant support values are indicated (upper, ML bootstrap > 50%; lower, Bayesian posterior probability > 0.90)