734 research outputs found
Method to control a photovoltaic plant and corresponding control apparatus
No full textApparatus to control a photovoltaic plant comprising at least a string of photovoltaic modules connected to an electric energy converter, and a switch connected in parallel to said string and to said electric energy converter
An accurate fourier-series expansion for round-rotor electric machine permeance function including large eccentricity effects
No full textOne of the key tasks in the modeling of electric machines is the analytical expression of self and mutual phase inductances as a function of the rotor position. Winding and permeance functions are a powerful tool for this purpose. This paper investigates the expression of the air-gap permeance function for a round rotor machine subject to pronounced eccentricity. An expression is sought in the form of a Fourier series expansion in order to make it suitable for modeling purposes. Although derived through non trivial algebraic passages, the final expression proposed is proved to be accurate and computationally efficient as the theoretically infinite sums involved in it exhibit a very rapid convergence to their asymptotical values
Memoirs of San Martino, Italy and History of the San Martino Club in Trail, B.C
No full textThis paper details the history of Italian immigrants in Trail, their homeland in San Martino, Italy, and the activities that the San Martino Club puts on in Trail. Food, games, and other cultural traditions are described, having been brought over from Italy to Canada, and kept alive in part through the communal effort of the San Martino Club.Student paper submitted for Anthropology 101
Nutritional value of canola expellers produced "on farm" by cold extraction of oil used as bio fuel
No full textGeneral aim of this thesis was to study canola expellers (CE) extracted by cold pressing in a small plant (on farm) and to evaluate the validity to use this by-product in ruminant feeding. The thesis includes the results of four experimental contributes: the first one aimed to evaluate the stability of CE at different times and temperatures of storage in order to determine if the conditions usually found in the farms, especially during the hot season, can result in changes in fatty acids profile and in some oxidative parameters. Results found that under different temperatures (12, 24, and 36°C) and times of storage (10, 20, and 30 d), CE maintained a good oxidative stability, as evidenced by low peroxide values (< 10 mEq/kg fat) in all samples collected, by negative response for Kreis test and by low changes in fatty acids profile. From these results it could be hypothesized that the storage of these by-products did not change the characteristics of the lipid fraction. In the second contribute in vitro gas production (GP) values obtained from the incubation of CE, whole soybean seed (WSS) and soybean meal (SBM) were compared, incubating feed samples with two media containing N-rich buffer or N-free buffer, in order to compare the effect of the availability of feed as unique protein source. Results of the experiment showed that CE is an easily degradable protein source. In the first hours of incubation with limiting N availability, higher gas production was recorded compared to the two soybeans. On this basis, CE could be interesting in diets at low protein content, currently suggested in order to reduce nitrogen excretion. No toxic effects on the microbial yield were observed during the fermentation of the three different feeds. The third contribute compared four diets formulated for beef cattle, based on corn silage and containing WSS or CE as protein sources at two different inclusion levels, in order to obtain 15 and 11 % CP of DM in the diets. Diets were tested using Rusitec fermenter. Compared to WSS, CE provided greater NDF degradability (P < 0.01), produced less acetate and propionate (P < 0.001) but more butyrate and branched-chain VFA. The total VFA production was similar for the two protein sources. With regard to nitrogen balance, CE showed greater 15N enrichment in the non-ammonia N (P < 0.01) and nominally lower values of microbial N derived from ammonia compared to WSS (P = 0.06). At high inclusion level, the 15N enrichments for ammonia N, non-ammonia N and total bacteria N were also greater than observed at low inclusion levels (P < 0.001). In conclusion, the two feeds showed different fermentation patterns. The manipulation of dietary protein level seemed to lead primarily to a variation of bypass protein, without effects on the synthesis of microbial N.
In the fourth contribute the same diets tested in Rusitec fermenter (third contribute) were evaluated using RF system (Ankom Technology, Macedon, NY, USA) in order to evaluate their gas production kinetics. Results showed that both NDFd and TDMd values were greater (P<0.05) for CE diets compared to WSS, confirming the results obtained with Rusitec and as expected were lower (P=0.04) for L compared to H diets. Compared to WSS, CE inclusion in the diets increased the rate of GP (P<0.05;) but did not affect the total amount of GP. The reduction of CP level in the diets from 15 to 11% decreased the rate of GP without effects on total GP. Ammonia content increased (P<0.01), as expected, with the level of dietary CP. In conclusion, when diets with low CE levels are used, the inclusion of rapeseed cake in replacement to soybean seeds could improve the rate of degradation during the first hours of fermentation. In general CE obtained by cold extraction on farm could be an interesting feed in ruminant feeding with economical and environmental benefits
Practical assessment of homothetic dimensioning criteria for induction motors
No full textInduction motors are presently the most widespread kind of electric machinery used in industrial applications. In the engineering practice, it frequently happens that designers or final users have to roughly estimate the size, weight and some basic performance data of an induction motor based on few specification requirements such as its rated speed and power. This paper describes homothety as an effective answer to this problem. The main principles of homothety as an induction motor sizing approach are discussed and quantitative formulas are derived based on theoretical considerations. The homotetic laws are finally assessed considering a set of sample built four-pole machines (whose data are fully available). The assessment confirms homothety as an actually powerful approach for a first-attempt estimation of many motor data including size, weight, utilization factor, current density, electric loading, etc
Change in body condition score of Holstein cows as affected by parity and mature equivalent milk yield
No full textCows from 25 dairy herds were scored for body
condition at 3-mo intervals for over 2 yr to study the
pattern of changes during lactation and the effects of
parity and milk yield capability of cows on changes in
body reserves. Data were recorded for 1395 Holstein
cows grouped into three parity classes and five classes
of mature equivalent milk yield. The analysis model
accounted for nearly 70% of the variation in body
condition score. Body reserves decreased during early
lactation until about 100 DIM and were restored during
mid and late lactation. The pattern of change in
body condition score varied among lactations and
dairy merit of cows. Depletion and subsequent recovery
of body reserves were less intense for primiparous
cows than for multiparous cows. Loss of body condition
scores was higher and more prolonged for cows of
higher dairy merit. The minimum body condition
score occurred at 3 mo after calving for the worst
yielding cows and at 4 mo after calving for the best
yielding cows; the highest yielding cows had twice the
loss in body condition as the lowest yielding cows.
General equations are presented as a proposed guideline
to examine changes in body condition score of
Holstein cows of different parities and dairy merit
Investigation into induction motor equivalent circuit parameter dependency on current and frequency variations
No full textInduction motors are presently the most widespread kind of electric machinery used for industrial and general purpose applications. The parameters of their equivalent circuit model can be determined with a combination of magneto-static and time-harmonic Finite Element Analysis (FEA) simulations. This paper investigates how equivalent circuit parameters depend on current and frequency variations. Calculation results obtained from FEA combined with analytical formulas are experimentally assessed by measurements on a small sample motor used for household appliances
Ethos Presenza Storia: la ricerca filosofica di Ernesto De Martino
No full textSergio Fabio Berardini ha scelto di concentrare il proprio interesse scientifico sul versante squisitamente antropologico del pensiero di De Martino, sottoponendo ad un esame accurato e penetrante la nozione di “ethos trascendentale del trascendimento”: «ethos specificamente e uni-versalmente umano che è trascendimento della vita secondo valorizzazioni comunitarie e tendenzialmente intersoggettive». Si tratta di una nozione-chiave, ricca d’implicazioni di estrema importanza, senza la quale l’intero ‘edificio’ costruito da De Martino risulta inafferrabile nella sua effettiva complessità: per metterne a fuoco il significato d’insieme e le molteplici sfaccettature, Berardini si è addentrato con perizia nell’analisi delle moderne correnti filosofiche europee e italiane. Il risultato è un quadro affascinante, di notevole pregio, sostenuto da una scrittura elegante, immune da tecnicismi gratuiti, dal quale affiora l’originalità del pensiero demartiniano.
(dalla Prefazione di Marcello Massenzio
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