337 research outputs found
Gradient Pattern Analysis of Cosmic Structure Formation: Norm and Phase Statistics
This paper presents the preliminary results of the characterization of
pattern evolution in the process of cosmic structure formation. We are applying
on N-body cosmological simulations data the technique proposed by Rosa, Sharma
& Valdivia (1999) and Ramos et al. (2000) to estimate the time behavior of
asymmetries in the gradient field. The gradient pattern analysis is a well
tested tool, used to build asymmetrical fragmentation parameters estimated over
a gradient field of an image matrix able to quantify a complexity measure of
nonlinear extended systems. In this investigation we work with the high
resolution cosmological data simulated by the Virgo consortium, in different
time steps, in order to obtain a diagnostic of the spatio-temporal disorder in
the matter density field. We perform the calculations of the gradient vectors
statistics, such as mean, variance, skewness, kurtosis, and correlations on the
gradient field. Our main goal is to determine different dynamical regimes
through the analysis of complex patterns arising from the evolutionary process
of structure formation. The results show that the gradient pattern technique,
specially the statistical analysis of second and third gradient moment, may
represent a very useful tool to describe the matter clustering in the Universe.Comment: Accepted for publication in Physica
Physiological and behavioural parameters of broiler chicks grown under different heating systems
Received: December 1st, 2022 ; Accepted: March 29th, 2023 ; Published: April 24th
, 2023 ; Correspondence: [email protected] study aimed to compare the internal environment, physiological variables, and
behavioural responses of chicks under two different heating systems. The experiment was
performed in two commercial broiler houses located in Brazil, where 28,000 male Cobb chicks
were housed during the first three weeks of life. One of the broiler houses was heated by an
industrial indirect-fired biomass furnace (S1). In addition, another heating system consisting of
two furnaces for indirect heating of the air using biomass (wood) as fuel, built by hand with
bricks, mud, and dung on an iron structure (S2), was tested. Measurements of the dry bulb
temperature (tdb), dew point temperature (tdp), and relative air humidity (RH) were performed.
Subsequently, the temperature-humidity index (THI) was calculated. In addition, the
physiological variables of the respiratory rate (RR) and cloacal temperature (tcloacal) were
measured three times a day (8:00 am, 2:00 pm, and 6:00 pm) in four chicks. The behaviours were
grouped by dendrograms, in which the similarity of these data was qualified. During the second
and third weeks of life, the THI values were below the recommended range. The RR and tcloacal
data were below the recommended comfort values, which may be an indicator that the chicks
were subjected to cold conditions. Regarding their behaviour, the chicks exhibited calm, feeding,
and sleepy behaviours most of the time. Problems in the heating system inside the broiler house
could be observed, possibly affecting the chicks’ thermal comfort and welfare, which
consequently can result in productive and economic losses
Comparison of airflow homogeneity in Compost Dairy Barns with different ventilation systems using the CFD model
In the pursuit of high milk productivity, producers are using confinement systems in
order to improve performance and animal welfare. Among the housing systems, the Compost
bedded-pack barns (CBP) stand out. In these barns a bedding area is provided inside, where cows
move freely. Generally this area is covered with carbon source material (such as sawdust or fine
dry wood shavings) which together with manure, thanks a regular mechanically stirring, ensures
the aerobic composting process. The ventilation in these facilities has the function of
dehumidifying the air, improving the air quality, drying the bedding, improving the thermal
comfort conditions of the confined animals. This work aimed at validating a computational model
using Computational Fluid Dynamics (CFD) to determine the best homogeneity of airflows
generated by different forced ventilation systems used in CBP barns. Two CBP barns were
compared with different ventilation systems: high volume low speed (HVLS) and low volume
high-speed (LVHS) fans. The results showed that the proposed model was satisfactory to predict
the flows generated by both types of fans. It was concluded that the use of HVLS fans produced
a more homogeneous airflow when compared to LVHS fans. The use of mechanical ventilation
in tropical conditions is necessary for the proper functioning of the system. In this study, the
systems used promoted the increase in air speed to levels close to adequate
Estimate of manure present in compost dairy barn systems for sizing of manure storage
Milk production is increasingly modernized as a result of the growing demand for food
around the world. Improvements in livestock facilities are observed, with a large increase in the
use of feedlot systems such as the Compost Dairy Barn. Increasing milk production in
confinement systems has also raised concerns such as the management of wastes (water, faeces
and urine) from the system, which has become one of the most important issues in the intensive
dairy farms. The aim of this work was to estimate the amount of manure present in compost dairy
barn systems in order to size the manure storage. The study was conducted at four compost dairy
barns in southern Minas Gerais, Brazil. These compost barns had different bedding materials and
dimensions. In each farm, data on milk yield and quality (daily production, fat and protein
content), animal weight and amount of feed ingested by the animals were collected. Total-day
manure delivered by the cows in the feeding alley and milking parlour was piled up together and
weighed. Based on the results, it was observed that, in the compost dairy barns, only part of the
total manure produced per day was delivered in the milking parlour (1.6 and 2.0%) and in the
feed alley (27.6 to 49.3%). These results are very important for designers for the proper manure
management system design of the dairy farms
Analysis of environmental conditions in two different Compost Bedded Pack Barn systems for dairy cattle
Received: February 1st, 2023 ; Accepted: April 27th, 2023 ; Published: May 10th, 2023 ; Correspondence: [email protected], [email protected] objective of this study was to analyse and compare the thermal environment of
dairy cattle facilities in an open compost bedded pack barn (CBP) with natural ventilation and
closed CBP (without thermal insulation) and climate control system. The research was conducted
in a property located in Zona da Mata, Minas Gerais, Brazil. During the summer and for different
periods of the day, the following average environmental variables observed inside the facilities
were measured: dry bulb temperature, relative humidity and Temperature and Humidity Index
(THI). The results were submitted to an analysis of variance to determine the significance of the
variables in the different treatments. It was found that the closed and climate control system CBP
promoted greater control of the facility's internal microclimate, registering smaller thermal
amplitudes and a greater reduction in the animals' exposure time to stressful thermal conditions,
compared to the CBP with natural ventilation. However, during summer afternoons, comfort
indices indicated moderate stress. It is concluded that the closed CBP, regarding the analysed
variables, indicated potential use, provided that a careful study of the climate of the region is
carried out before implementation, the factors related to the ambient conditioning and better
insulation of the construction are adjusted. The climatic variables inside the open CBP indicated
a high stress condition for the animals, suggesting the placement of positive pressure fans and
sprinklers properly distributed in the feed alley, to guarantee benefits to the entire area of the
animal housing
Analysis of environmental conditions and management in a compost-bedded pack barn with tunnel ventilation
Received: January 5th, 2021 ; Accepted: March 27th, 2021 ; Published: April 16th, 2021 ; Correspondence: [email protected] housing system based on compost-bedded pack for dairy cows is spreading rapidly
in Brazil. Completely open buildings without curtains and simple roofs are usually provided.
However, in the last years some new completely closed barns have been realized. This study aims
to analyse one of these closed barns, located in the State of Minas Gerais. The two main sides of
the facility are provided with polyethylene curtains of blue colour and five deflectors. The barn
is equipped with an evaporative adiabatic cooling system, associated with the tunnel-style
ventilation, realized with exhaust fans, continuously operating 24 hours a day. 85 lactating
Holstein cows were housed in the barn during the trials carried out in the winter season 2019.
Microclimatic data were collected continuously. Air speed, illuminance and bedding temperature
were measured during the farm visits. Pack moisture was calculated. The results state the
importance of bedding management and climatic conditions inside the barn. It emerges that the
cows housed in this kind of closed barn, with forced ventilation, are in good thermal conditions,
which are fairly constant. The average illumination of the barn can be considered acceptable
(55.06 lx), even if some areas of the barn present values below the minimum ones reported in
literature. The bedding temperature varies between a maximum of 36.33 °C and a minimum of
25.44 °C with an average of 31.26 °C. The values of bedding moisture are between a maximum
of 64.36% and a minimum of 60.81% with an average of 62.48%
Spatial distribution of bed variables, animal welfare indicators, and milk production in a closed compost-bedded pack barn with a negative tunnel ventilation system
This research aimed to characterize, evaluate and compare the spatial distribution of the leading bed variables,
animal welfare indicators, and milk production in a closed compost-bedded pack barn (CBP) with a negative
tunnel ventilation system, for summer and winter periods. The study was carried out in a CBP located in the Zona
da Mata region, Minas Gerais, Brazil. The geostatistical modeling technique evaluated the variables of temper ature, moisture content, and pH (on the surface and depth of 0.20m) across the length of the bed. Bed samples
were characterized for carbon (C), nitrogen (N), and C:N ratio. Cows housed in the CBP were assessed for
locomotion and hygiene scores and average milk production. To evaluate the thermoregulation of the cows, the
respiratory rate (RR) and surface temperature (ST) were measured. Geostatistical analysis showed spatial
dependence and the non-uniformity of the spatial distribution of bed variables. The worst levels of bed tem perature and moisture were found in the regions close to the evaporative cooling plate, surrounding the feeding
alley, and in the region with the highest cow stocking. The C:N ratio, obtained in both climatic seasons of the
year, remained outside the recommended range for ideal composting. During the summer and winter, the bed
variables’ values suggest that the material was below levels for optimal composting; however, the aerated inner
layer was biologically active. The high animal density significantly impacted the worsening of the bed moisture
content and internal temperature. In general, dairy cows showed adequate hygiene (score of 1 and 2) and
locomotion (score of 0 and 1) scores for the two climatic seasons evaluated, indicating good welfare conditions.
In relation to RR and ST, the summer period presented less favorable environmental conditions. During winter,
the average milk production was 28.1 ± 7.2 kg day-1, and during summer, it was 26.9 ± 6.7 kg day-1
Rare earth element and yttrium geochemistry applied to the genetic study of cryolite ore at the Pitinga Mine (Amazon, Brazil)
This work aims at the geochemical study of Pitinga cryolite mineralization through REE and Y analyses in disseminated and massive cryolite ore deposits, as well as in fluorite occurrences. REE signatures in fluorite and cryolite are similar to those in the Madeira albite granite. The highest ΣREE values are found in magmatic cryolite (677 to 1345 ppm); ΣREE is lower in massive cryolite. Average values for the different cryolite types are 10.3 ppm, 6.66 ppm and 8.38 ppm (for nucleated, caramel and white types, respectively). Disseminated fluorite displays higher ΣREE values (1708 and 1526ppm) than fluorite in late veins(34.81ppm). Yttrium concentration is higher in disseminated fluorite and in magmatic cryolite. The evolution of several parameters (REEtotal, LREE/HREE, Y) was followed throughout successive stages of evolution in albite granites and associated mineralization. At the end of the process, late cryolite was formed with low REEtotal content. REE data indicate that the MCD was formed by, and the disseminated ore enriched by (additional formation of hydrothermal disseminated cryolite), hydrothermal fluids, residual from albite granite. The presence of tetrads is poorly defined, although nucleated, caramel and white cryolite types show evidence for tetrad effect.Este trabalho enfoca a geoquímica de elementos terras raras (ETR) e de Y no minério criolítico disseminado, no depósito criolítico maciço e na fluorita associada na mina Pitinga. As assinaturas de ETR na criolita e fluorita são similares àquelas do granito Madeira. Os maiores valores de SETR são encontrados na criolita magmática disseminada (677 a 1.345 ppm); SETR é menor na criolita maciça, com valores médios de 10,3 ppm, 6,66 ppm e 8,38 ppm, respectivamente, nos tipos de criolita nucleada, caramelo e branca. A fluorita magmática disseminada apresenta os valores mais altos de SETR (1.708 e 1.526 ppm), contrastando com a fluorita de veio tardio(34,81 ppm). A concentração de Y é maior na fluorita disseminada e na criolita magmática. As evoluções de diversos parâmetros (SETR, ETRL/ETRP, Y) podem ser seguidas através dos sucessivos estágios de evolução dos albita granitos e mineralização associada. Os dados de ETR indicam que o depósito criolítico maciço foi formado por, e o minério disseminado enriquecido por (formação adicional criolita disseminada hidrotermal), fluidos hidrotermais residuais do albita granito. A presença do efeito tetrad não é bem definida, embora as criolitas maciças nucleada, caramelo e branca apresentem algumas evidências deste efeito.FINEPAgência para o Desenvolvimento da Indústria Mineral do BrasilConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) - Departamento Nacional de Produção MineralFundação de Amparo à Pesquisa do Estado do Rio Grande do Sul (FAPERGS) - Programa de Apoio a Núcleos de ExcelênciaCNP
Effect of environmental temperature during the of brooding period on growing period of pullets viscera and tibia
ArticlePoultry production in subtropical and tropical regions faces many problems, one of
which is the high air temperature causing thermal stress, particularly dangerous in high-producing
birds. Thus, the negative effects caused by heat stress (HS) must be managed. The objective of
this study was to evaluate the effects of four different levels of HS in viscera and tibia of pullets.
A total of 648 chicks (Lohmann LSL Lite) were used in this study in two different phases. The
pre-experimental phase (PEP) was from day 1 through 6 weeks of age. The birds were reared
with three different environmental temperatures: thermal comfort, hot and cold. The experimental
phase (EP) was conducted from the 7th to the 17th week. Pullets from each thermal environment
of the PEP were submitted to: 20 °C, 25 °C, 30 °C, 35 °C. At the end of the 17th week of age 120
pullets were euthanatized and the organs, heart, liver, spleen and gizzard were weighed, as also
their tibias. Effects of PEP, and its interaction with EP, were not significant (P < 0.05) for viscera
and tibia weight. However, a significant increase (P < 0.05) in heart weight with the decrease of
the environmental temperature was observed, being the pullets subject to 20ºC and 25 °C with
the heaviest weights. For the liver, pullets subject to the 35 °C had the lowest weight and were
different (P < 0.05) from the other three treatments. For gizzard, the difference (P < 0.05) was
between the treatments 20ºC and 35 °C. These results indicate that brooding temperatures tested
during the first 6 weeks of life did not affect the viscera and bone weight during the growing
phase
Alternative form to obtain the black globe temperature from environmental variables
ArticleReaching thermal comfort conditions of animals is essential to improve well-being and
to obtain good productive performance. For that reason, farmers require tools to monitor the
microclimatic situation inside the barn. Black Globe-Humidity Index (BGHI) acts as a producer
management tool, assisting in the management of the thermal environment and in decision
making how protect animals from heat stress. The objective of this work was to develop a
mathematical model to estimate the black globe temperature starting from air temperature,
relative humidity and air velocity. To reach this goal, data of air temperature and humidity were
collected, with the aid of recording sensors. The black globe temperature was measured with a
black copper globe thermometer and the air velocity was monitored with a hot wire anemometer.
Data were analysed using a regression model to predict the black globe temperature as a function
of the other variables monitored. The model was evaluated, based on the significance of the
regression and the regression parameters, and the coefficient of determination (R²). The model
proved to be adequate for the estimation of the black globe temperature with R2 = 0.9166 and the
regression and its parameters being significant (p < 0.05). The percentage error of the model was
low (approximately 2.2%). In conclusion, a high relation between the data estimated by the model
with the data obtained by the standard black globe thermometer was demonstrated
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