Relative Air Research Articles

Biochar, manure and superabsorbent improve the physical quality of saline‐sodic soil under greenhouse conditions

AbstractThe increasing salinization and sodification of soils in drylands and irrigated systems present a great challenge to agricultural production and threaten soil quality. There is an urgent need to investigate potential strategies to remediate soils that are threatened by these processes. To address this challenge, the current study investigated the effects of organic and inorganic amendments and leaching fraction (LF) on physical and hydraulic properties including the soil water characteristic curve (SWCC), Dexter's index of soil physical quality (SDexter), bulk density (BD), saturated hydraulic conductivity (Ks), and water repellency index (RI) in a saline‐sodic soil. A greenhouse experiment was carried out in a completely randomized design with two factors (amendment and LF). The amendments included superabsorbent (1%) (SA), zeolite modified with CaCl2 (2%) (ZC), biochar (2%) (B), biochar + manure (2%) (BM), and a control (no amendment) (CT), and combined with two levels of LF (15% and 30%). Spring wheat (Triticum aestivum, ‘UG99’) was planted in the soil columns. After harvest, undisturbed samples were collected from each column for the determination of soil properties. The results demonstrated the effectiveness of the SA and organic amendments to enhance Ks and decrease BD. There was a significant (p < 0.01) positive effect of the amendments, particularly biochar and superabsorbent on the soil pore size distribution. The SA amendment significantly increased soil water retention, especially at high matric potentials (i.e., 0 to −80 hPa). The effect of organic amendments on the SWCC was in between those of the ZC and SA amendments. The SA and BM treatments were sub‐critically water repellent, while the ZC treatment increased soil water repellency. The SA, B, and BM15 treatments exhibited very good physical quality (SDexter > 0.05). The relative air and moisture capacities were optimal in the B‐amended soil at field capacity (matric potential –330 hPa). We conclude that B, BM, and SA are suitable amendments for reducing the adverse effects of salinity and sodicity via an improvement in soil physical quality.

Impact of environmental factors on COVID-19 transmission: spatial variations in the world

ABSTRACT The COVID-19 pandemic caused enormous destruction to global health and the economy and has surged worldwide with colossal morbidity and mortality. The pattern of the COVID infection varies in diverse regions of the world based on the variations in the geographic environment. The multivariate generalized linear regression models: zero-inflated negative binomial regression, and the zero-inflated Poisson regression model, have been employed to determine the significant meteorological factors responsible for the spread of the pandemic in different continents. Asia experienced a high COVID-19 infection, and death was extreme in Europe. Relative humidity, air pressure, and wind speed are the salient factors significantly impacting the spread of COVID-19 in Africa. Death due to COVID-19 in Asia is influenced by air pressure, temperature, precipitation, and relative humidity. Air pressure and temperature substantially affect the spread of the pandemic in Europe.

Growth and toxin production of phomopsin A and ochratoxin A forming fungi under different storage conditions in a pea (Pisum sativum) model system

Phomopsins are mycotoxins mainly infesting lupines, with phomopsin A (PHOA) being the main mycotoxin. PHOA is produced by Diaporthe toxica, formerly assigned as toxigenic Phomopsis leptostromiformis, causing infections in lupine plants and harvested seeds. However, Diaporthe species may also grow on other grain legumes, similar to Aspergillus westerdijkiae as an especially potent ochratoxin A (OTA) producer. Formation of PHOA and OTA was investigated on whole field peas as model system to assess fungal growth and toxin production at adverse storage conditions. Field pea samples were inoculated with the two fungal strains at two water activity (aw) values of 0.94 and 0.98 and three different levels of 30, 50, and 80% relative air humidity.After 14 days at an aw value of 0.98, the fungi produced 4.49 to 34.3 mg/kg PHOA and 1.44 to 3.35 g/kg OTA, respectively. Strains of D. toxica also tested showed higher PHOA concentrations of 28.3 to 32.4 mg/kg.D. toxica strains did not grow or produce PHOA at an aw values of 0.94, while A. westerdijkiae still showed growth and OTA production.Elevated water activity has a major impact both on OTA and, even more pronouncedly, on PHOA formation and thus, proper drying and storage of lupins as well as other grain legumes is crucial for product safety.

Assessment of State-Space Building Energy System Models in Terms of Stability and Controllability

Building energy management system involves the development of control strategies for the heating, ventilation, and air-conditioning (HVAC), as well as lighting, systems. Building energy modeling is a significant part of designing such strategies. In order to analyze the feasibility of a building energy system model for any desired control strategy, a mathematical assessment tool is developed in this paper. A multi-input multi-output (MIMO) building energy system model, consisting of an outdoor wall, an external wall, two partition walls, one roof, and a ceiling, has been considered as the virtual test setup. A methodology for conducting stability and controllability assessment tests on the building energy model is proposed using inverse dynamics input theory (IDIT). IDIT enables the decoupling of control variables so as to enable the conversion of an MIMO system to a number of independent single-input single-output systems. The controllability is assessed based on the design properties for continuous systems: asymptotes and transmission zeros. The results show that the relative humidity and air temperature of the building space were controllable for all operating points; however, in unconditioned situations, where the humidity levels of the building space were greater than that of the outdoor levels, the models were unstable.

TECHNICAL FEATURES OF USING A COMPLEX WIND-SOLAR POWER SUPPLY SYSTEM OF AN ENERGY-EFFICIENT HOUSE


 
 
 The wish to achieve energy savings of organic fuel while reducing the negative man-made impact on the environment, especially in the context of global warming, encourages for the search for new approaches in the construction of energy efficient houses and buildings. Analysis of the accumulated meteorological data on wind and solar potentials in Kyiv shows that in an urban city it is possible to create a fully autonomous house, which will be supplied with electricity using solar and wind energy. Year-round monitoring of atmospheric parameters such as current values of wind speed and direction, relative humidity and barometric air pressure was carried out using a portable meteorological station TFA Nexus using appropriate Primus software, which allowed to collect and analyze measurement data. Data on insolation for the location of the energy-efficient house were obtained experimentally in 2019 using measurements with a pyranometer SR-U1. The developed system consists of a wind generator, solar modules, charge controllers, inverters and batteries. The calculation of electricity production by the solar station was performed in the PVSyst program according to meteorological data Meteonorm. At the same time, it should be noted that the energy contribution from photomodules is crucial for the power supply of an energy-efficient house. The proposed instrumental methods for determining the parameters of insolation provide an opportunity to assess its technically available potential for a given area, as well as to use the obtained data for the design of complex power supply systems using energy of wind and solar. The research results prove that in the conditions of the city of Kyiv there are potential opportunities for the creation of residential buildings with zero energy balance, in which, for the purpose of power supply, wind generators and solar modules can be used quite successfully.
 
 

Influence of relative humidity and air temperature on the stopping position of the automatic tool changer in a CNC machine when using a pneumatic cylinder

The automatic tool changer (ATC) in computerized numerical control (CNC) milling machine often uses pneumatic dynamic sources. Friction in the pneumatic cylinder affects the ATC’s stopping position; this friction depends on many factors, including the air environment’s relative humidity and temperature. This paper presents the results of research on the effects of relative humidity (RH) and air temperature (T) on the stopping position of an ATC using a pneumatic cylinder. Studies were conducted at temperatures of [Formula: see text]C, [Formula: see text]C and [Formula: see text]C and relative humidity values of 51%, 75% and 99% for different speeds of the pneumatic cylinder (30, 50 and 100 mm/s). The results show that when the humidity increases from 51% to 99% and the temperature increases from [Formula: see text]C to [Formula: see text]C, the friction force decreases. The friction force is related to the relative humidity and temperature of the air. Thus, the deviation of the ATC’s stopping position depends on the relative humidity and temperature of the area under investigation.

The effect of air temperature on hospital admission of adults with community acquired pneumonia in Baotou, China

The relationship between air temperature and the hospital admission of adult patients with community-acquired pneumonia (CAP) was analyzed. The hospitalization data pertaining to adult CAP patients (age ≥ 18 years) in two tertiary comprehensive hospitals in Baotou, Inner Mongolia Autonomous Region, China from 2014 to 2018 and meteorological data there in the corresponding period were collected. The exposure–response relationship between the daily average temperature and the hospital admission of adult CAP patients was quantified by using a distributed lag non-linear model. A total of 4466 cases of adult patients with CAP were admitted. After eliminating some confounding factors such as relative humidity, wind speed, air pressure, long-term trend, and seasonal trend, a lower temperature was found to be associated with a higher risk of adult CAP. Compared to 21 °C, lower temperature range of 4 to –12 °C was associated with a greater number of CAP hospitalizations among those aged ≥ 65 years, and the highest relative risk (RR) was 2.80 (95% CI 1.15–6.80) at a temperature of − 10 °C. For those < 65 years, lower temperature was not related to CAP hospitalizations. Cumulative lag RRs of low temperature with CAP hospitalizations indicate that the risk associated with colder temperatures appeared at a lag of 0–7 days. For those ≥ 65 years, the cumulative RR of CAP hospitalizations over lagging days 0–5 was 1.89 (95% CI 1.01–3. 56). In brief, the lower temperature had age-specific effects on CAP hospitalizations in Baotou, China, especially among those aged ≥ 65 years.

Analysis of the Response of Urban Water Consumption to Climatic Variables: Case Study of Khorramabad City in Iran

Iran is located in a dry climate belt. Such conditions have made the supply of urban water resources one of the most fundamental management challenges. The amount of water consumed in a city is affected by the weather conditions greatly such that as the weather changes, the amount of water consumed changes as well. In this study, several models including zero-order Pearson’s correlation coefficient, first-order Pearson’s correlation, generalized additive model (GAM), generalized linear model (GLM), support vector machine (SVM-Nu), and simplex optimization algorithm were used in order to identify linear/nonlinear reactions of monthly water consumption to the individual and combined associations of meteorological variables (temperature, air pressure, and relative humidity) in Khorramabad city. Zero-order and first-order correlations showed that, by controlling the air temperature, the effect of pressure and relative humidity on changes in water consumption increase. On the other hand, both individual and combined GAM models showed the same result in the nonlinear response of water consumption to the changes in relative humidity and air pressure. The spline method also revealed that, by eliminating the effect of air temperature, the nonlinear reaction of water consumption to changes in pressure and relative humidity was increasing, and by eliminating the effects of the relative humidity and air pressure, the nonlinear reaction of water consumption to the air temperature was intensified. In general, by decreasing the air pressure and temperature, the amount of urban household water consumption decreases drastically. These conditions are generally provided by entering low-pressure systems.

Severe acute respiratory syndrome coronavirus-2 medical solid waste treatment: A need for efficient and effective strategies in low-resourced settings.

Understanding infections related to handling healthcare waste products is of critical importance and the application of simple and low-cost strategies remain a priority in low-income and middle-income countries to protect healthcare workers. We examined the potential effect of relative humidity (RH), air temperature and ultraviolet irradiation (UI) to establish an efficient and effective way to facilitate disposal of medical waste. Literature is emerging on the effect of high RH and high temperature, which would increase airborne mass deposition and decrease the viability of viruses in both airborne particles and on surfaces. On the other hand, severe acute respiratory syndrome coronavirus-2 has been proven to be susceptible to UI when suspended in air like other coronaviruses. An innovative approach utilizing environmental conditions might represent an effective and efficient way to ensure better and sustainable protection of the healthcare workers in low-resourced settings.

Extensão do PMV para avaliação do conforto térmico de idosas em ambientes com ventilação natural

O envelhecimento populacional torna necessário criar condições para que idosos vivam com qualidade de vida. O conforto térmico das edificações é fundamental para atingir essa meta. Esta pesquisa analisou a aplicabilidade do Voto Médio Estimado (PMV) e a sua extensão (PMVe) para avaliação do conforto térmico de idosas, com idade igual ou superior a 60 anos. O estudo foi aplicado em dois residenciais geriátricos naturalmente ventilados localizados em Santa Maria, RS, região de clima temperado com verão quente. As variáveis ambientais temperatura do ar, umidade relativa do ar, temperatura de globo e velocidade do ar foram medidas e foram aplicados questionários para o levantamento da sensação e preferência térmicas das idosas e das variáveis vestimenta e atividade metabólica. Então, calculou-se o índice de sensação de conforto. A sensação térmica real dos usuários foi comparada com o PMV e o PMVe, com fatores de correção de 0,5, 0,7 e 0,9. Comparando os três valores de PMVe, estimou-se que, quanto menor o fator expectativa, menor é a diferença entre PMVe e sensação térmica para valores negativos (frio). O PMVe com fator de correção 0,5 apresentou perfeita correlação das variáveis PMV e sensação térmica relatada em 11,54% das medições, já o PMVe de 0,7 e de 0,9 não apresentaram nenhum ponto sobre a reta de referência. O estudo mostrou que a extensão do PMV não corrige as imprecisões do modelo, mas reduz as diferenças encontradas com os valores de sensação térmica relatada, diminuindo a superestimação da sensação de frio que o PMV resultava para as idosas.

The influence of microclimate on the calves' bodies in the bioclimatic conditions of the Caspian lowlands in Dagestan

The aim of our research was to study the microclimate's influence on some clinical and physiological parameters of calves in the conditions of livestock complexes of the Republic of Dagestan. Research methods: veterinary, zootechnical, logical, systemic. The results of the study of calf pen microclimate parameters showed the range of fluctuations: temperature 6,5-22,5 0 C, humidity 74.2 -98.1%, air velocity 0.25- 0.40m/s, carbon dioxide concentration 0.4 -0.2% and ammonia 2-6 mg/m3. The study results of the clinical and physiological calves’ state showed changes in body temperature from 38.0 to 39.3 0C, pulse rate from 65 to 71 beats per minute, respiratory frequency movements from 22 to 26 per minute. The results of hematological studies has shown that the studied indicators had a range of fluctuations: hemoglobin 8.6 - 9.4 g%, erythrocytes 7.1-7,9, leukocytes 7.2-8.9 th./mm3. Conclusions. The study results of the calf pen microclimate showed that it complied with zoohygienic norms. The relative humidity and air velocity indicators exceeded the permissible zoohygienic standards. Indicators of calves’ physiological condition corresponded to the norms of a healthy animal. Hematological and biochemical blood indicators of calves were within the physiological norm.

Field Study on Adaptive Thermal Comfort in Coastal Building in China

Liu, J.; Yu, W., and Cai, T., 2020. Field study on adaptive thermal comfort in coastal building in China. In: Liu, X. and Zhao, L. (eds.), Today's Modern Coastal Society: Technical and Sociological Aspects of Coastal Research. Journal of Coastal Research, Special Issue No. 111, pp. 226–230. Coconut Creek (Florida), ISSN 0749-0208.Different from inland areas, coastal areas are usually characterized by greater wind speed, relative humidity, and solar radiation levels. The indoor thermal environment of coastal buildings attracts more attention as a result. A field investigation on winter indoor thermal condition and thermal comfort was conducted in coastal buildings in Haikou, China. The average indoor air temperature was 21.05 ± 2.77° C during the survey period. And 65.2% of temperature datasets were within winter comfort band in American Society of Heating, Refrigerating and Air-Conditioning Engineers 55 Standard. The influences of relative humidity and air speed were insignificant. The thermal neutral temperature and acceptable temperature band for 90% of participants were 22.97° C and 19.84–26.10° C, respectively. Subjects would like a warmer thermal environment in winter with preferred temperature of 25.44° C. It indicates that thermal neutrality sometimes deviates from desired thermal environment. Adjusting clothes was observed to be a predominant adaptive action, helping subjects adapt to the variations in ambient thermal environment. In addition, the comprehensive impacts of adaptations on thermal comfort were also validated by applying cross analysis between thermal acceptability and Actual Mean Vote, thermal preference. The results obtained in present study provide reference on indoor thermal environment optimization for coastal buildings in tropical island region.

Quantitative CT-based image registration metrics provide different ventilation and lung motion patterns in prone and supine positions in healthy subjects

BackgroundPrevious studies suggested that the prone position (PP) improves oxygenation and reduces mortality among patients with acute respiratory distress syndrome (ARDS). However, the mechanism of this clinical benefit of PP is not completely understood. The aim of the present study was to quantitatively compare regional characteristics of lung functions in the PP with those in the supine position (SP) using inspiratory and expiratory computed tomography (CT) scans.MethodsNinety subjects with normal pulmonary function and inspiration and expiration CT images were included in the study. Thirty-four subjects were scanned in PP, and 56 subjects were scanned in SP. Non-rigid image registration-based inspiratory-expiratory image matching assessment was used for regional lung function analysis. Tissue fractions (TF) were computed based on the CT density and compared on a lobar basis. Three registration-derived functional variables, relative regional air volume change (RRAVC), volumetric expansion ratio (J), and three-dimensional relative regional displacement (s*) were used to evaluate regional ventilation and deformation characteristics.ResultsJ was greater in PP than in SP in the right middle lobe (P = 0 .025), and RRAVC was increased in the upper and right middle lobes (P < 0.001). The ratio of the TF on inspiratory and expiratory scans, J, and RRAVC at the upper lobes to those at the middle and lower lobes and that ratio at the upper and middle lobes to those at the lower lobes of were all near unity in PP, and significantly higher than those in SP (0.98–1.06 vs 0.61–0.94, P < 0.001).ConclusionWe visually and quantitatively observed that PP not only induced more uniform contributions of regional lung ventilation along the ventral-dorsal axis but also minimized the lobar differences of lung functions in comparison with SP. This may help in the clinician’s search for an understanding of the benefits of the application of PP to the patients with ARDS or other gravitationally dependent pathologic lung diseases.Trial registrationRetrospectively registered.

Hydrothermal anomalies of the Earth's surface and crustal seismicity related to Ms8.0 Wenchuan EQ

Hydrothermal anomalies related to the Ms8.0 Wenchuan earthquake (EQ) on May 12, 2009, have been widely reported. However, the reported anomalies have not been associated with multi-geosphere analysis, and space–time analysis with crustal seismicity is lacking. In this paper, the space–time variation of hydrothermal parameters, including soil moisture, soil temperature, near-surface relative humidity (RHsig995) and air temperature (TMPsfc), was first extracted and analyzed with the NCEP-FNL reanalysis dataset. The b-value (a seismic parameter from the Gutenberg–Richter law) was calculated and mapped to unravel the crustal stress and rock rupture. Our results reveal a similar time window for hydrothermal anomalies on April 20 and April 30, 2008, and these anomalies are mainly distributed along the southern and middle parts of the Longmenshan fault zone. The surface temperature anomalies lag behind the humidity anomalies, and the accelerating stress accumulation started since June 2007 and lasted for eight to nine months before the mainshock. The b-value mapping shows a segmented difference along strike of the Longmenshan fault, and that regional stress accumulated mainly in the southern parts of the F2 and F3 faults. We propose the occurrence of a complex coupling process led by crustal stress buildup before the Wenchuan EQ. The anomalies are concentrated in the southern part of the surface rupture zone. The prolonged crustal stress accumulation corresponds to the short intermittent hydrothermal response on the Earth’s surface before the Wenchuan EQ. Our findings reveal new hydrothermal anomalies in the Earth’s surface and atmosphere and explore direct link with seismogenic processes in the crust.

RELATIVE CHLOROPHYLL INDEX OF MAIZE AND SOYBEAN ACCORDING TO WEATHER CONDITIONS AT DIFFERENT TIMES OF DAY

The present study aimed to identify the best day time to evaluate the relative chlorophyll index in maize and soybean crops as a function of weather conditions. The experiments were conducted in the 2018/2019 harvest, in January and February, in the experimental area of the State University of Goiás, Ipameri University Unit, in Ipameri-GO. A completely randomized design with three replications and 40 plants per plot was used. The measurements of relative chlorophyll index at 7:00, 10:00, 13:00, 16:00, and 19:00, at the maize stage R1 (silking) and soy stage R2 (full bloom), were evaluated. The replications consisted of alternating days over seven days. The relative chlorophyll index, leaf temperature, air temperature, and relative humidity, and light incidence were evaluated. The data were organized, and regression analysis was performed for all variables. The statistical analysis was processed using the Sisvar statistical analysis software. The maize shows higher values of relative chlorophyll index at times with the highest temperatures. For soybean, the relative chlorophyll index must be measured at temperatures close to 30 ºC. Studies with more species of C3 metabolisms, such as soybeans, should be carried out to standardize an adequate time to read the relative chlorophyll index.

AWARENESS OF THE EQUILIBRIUM MOISTURE CONTENT OF CHIA SEEDS IS AN IMPORTANT STEP TO PRESERVING IT

The article presents the results of studies of hygroscopic properties of chia seeds, which is a relatively new culturefor the Ukrainian industry. Chia seeds are a product with a high nutrient content and rich in trace elements, vitamins andminerals that can be of great benefit to human health. Therefore, the main task of post-harvest technology is to bring it to a state that will ensure long-term storage of chia seeds without loss in weight and poor quality. An important influence on the condition of the grain mass during storage and, in particular, during the initial treatment has its hygroscopicity, ie the ability to sorption and desorption of water vapor. Knowledge about the hygroscopic properties of grain are of practical importance for the scientific substantiation of the choice of rational modes of active ventilation, drying. The main characteristic of hygroscopic properties of grain materials is equilibrium moisture, so its determination is an important step for maintaining the quality of grain. The equilibrium moisture of chia seeds has been determined for the first time. The studies were carried out by the generally accepted tensimetric method in the range of air temperatures in the range of 5... 25 °C and iota relative humidity of 33...70 %, which model the conditions of storage of seeds and corresponding to the long-term average data, correspond to the warm and cold seasons in Odessa region. The influence of relative humidity, air temperature and grain moisture on the equilibrium moisture of chia was investigated, numerical values of equilibrium moisture of chia seeds were determined according to environmental parameters: temperature 5, 15, 25 °C and relative humidity 33, 45 and 70 %.The nature of the change in the equilibrium moisture of chia seeds was determined depending on the temperature and relative humidity. With increasing relative humidity and decreasing ambient temperature, the equilibrium moisture of chia seeds increases. The empirical coefficients and the equation that describes the dependence of the equilibrium moisture of chia seeds on the parameters of ambient air - temperature and relative humidity at which its change can be predicted.The data obtained can be used to select drying and active ventilation modes, as well as storage conditions for chia.

Numberical Simulation of Evapotranspiration with Limited Data in the Pearl River Basin

This research compared and analyzed the adaptation of four evapotranspiration equations: the FAO56 Penman-Monteith (PM), Priestley-Taylor, Hargreaves-Samani and Thornthwaite equations by using the day-to-day meteorological data of the 42 observation stations in the Pearl River basin. Numberical simulation of the four equations in different seasons and regions was made in order to find out the most suitable one for the evapotranspiration estimate in the Pearl River basin. Results show that the calculation results of the PM equation seem more stable in different seasons and regions, and is closer to the actual observation, due to the detailed consideration of the effects of aerodynamics and energy supply on evapotranspiration in its calculation procedure. The missing data of relative humidity, sunshine duration, wind speed and air pressure would have influence on the calculation accuracy of the PM equation. Temperature can be used to instead of the above variable in the PM equation, which is called the PMT equation. The applicability and the calculation accuracy is explored in this study. And the results show that the calculation results of the PMT equation is larger than those of the PM equation. By setting a correction coefficient in the PMT equation, the calculation accuracy can be obviously improved. Therefore, in the absence of other data, the PMT equation calculated only using temperature data can be use as an ideal equation for the evapotranspiration calculation and research in the Pearl River basin.

EXPERIMENTAL RESEARCH OF FIRES IN GRASSY ECOSYSTEMS

Formulation of the problem. The fire hazard of grass ecosystems depends on many factors that determine the proper condition of the combustible material and support the burning process. The most important indicators of danger are the condition and humidity of grass. The main external factors of influence on the occurrence and spread of fires in natural ecosystems are: air temperature and air relative humidity, precipitation, wind speed. The urgent task is to determine the rate of spread of fires in grassy ecosystems.&#x0D; The purpose of this work is to establish the features of occurrence and spread out of grass fires in the forest-steppe conditions of Ukraine on the basis of fire hazard analysis and experimental studies.&#x0D; Research methods. The studies were conducted in the forest-steppe zone in the Vinnytsia region on November 1-3, 2019. The plots with 10 m in length and 3 m in width were chosen, taking into account the wind direction along the plot. During the studies, the wind speed was in a range of 0 to 10 meters per second, the air temperature varied from 7 to 14 Celsium degrees during the day and from -3 to 12 Celsium degrees at night. The air humidity varied from 52 to 69 per cent during the day and from 72 to 84 per cent at night. The humidity of the grass was 20-22 per cent in the daytime, and 27-30 per cent at night. The fire load on the sites was 4-5 t/ha.&#x0D; The main results of the study. Combustion mostly did not happen since 19 p.m. till 10 a.m. because the grass cover during the night increased the moisture content due to the relative humidity increasing and drop of temperature. After 10 a.m. in clear conditions and in the presence of wind, the humidity of the grasses decreased, which facilitated their ignition and spread of fire. However, in the absence of wind, ignition did not happen.&#x0D; The fire spreading rate depended on wind speed and grass height. For grasses 40 cm high the fire spread rate was from 2.5 m/min (wind speed 1-2 m/s) to 3.5 m/min (wind speed 6-8 m/s). For grasses 60 cm high the fire spread rate was from 3.1 m/min (wind speed 1-2 m/s) to 12.5 m/min (wind speed 6-8 m/s).&#x0D; Conclusions. The rate of fire spread in grassу ecosystems depend on temperature and relative humidity, wind speed, grass humidity, height and spatial location. At night, the high humidity of grasses, caused by high relative humidity and low air temperature, hinders ignition and burning, but the fire may occur in the presence of wind in the presence of several sources of ignition with sufficient energy.

Calidad de poroto (Phaseolus vulgaris L.) almacenado en silobolsa en condiciones de intemperie en relación a la presencia de materias extrañas y granos partidos

El objetivo del trabajo fue estudiar el deterioro del poroto blanco alubia almacenado en silobolsa con la presencia de materias extrañas y granos partidos. Se evaluaron silobolsas con diferentes contenidos iniciales de humedad, materias extrañas, granos partidos y granos manchados. Se midió la evolución de estos parámetros y la concentración de dióxido de carbono. Se registró humedad relativa y temperatura del aire intergranario. Se utilizó la actividad acuosa como parámetro de actividad microbiana. Los resultados indican que el manchado de los granos aumentó con altos contenidos iniciales de manchado, humedad y materias extrañas, que coincidió con el incremento de microorganismos. Estos últimos se localizaron según la ubicación del material fino en la base de la bolsa, o en puntos húmedos del estrato superior producto de la condensación. Bajos valores de humedad y materias extrañas evidenciaron control microbiano por humedad relativa &lt;70%. Se observó interacción entre los efectos de materias extrañas y granos partidos, que generó el manchado de los granos, favorecida por períodos prolongados y altas temperaturas. El efecto de los granos partidos se relacionó con el contenido de humedad y el efecto del material extraño con el tiempo. Se observó la estratificación de la humedad. La concentración de dióxido de carbono aumentó con el incremento de la temperatura. Los incrementos de la actividad acuosa se relacionaron con altas proporciones de materias extrañas y granos partidos presentes en el granel, y con elevados contenidos de humedad de los mismos y del grano, lo cual ocasiona mayor actividad microbiológica.

Actual and Relative Soil Air Permeability as Soil Physical Quality Index

Developing indices to evaluate soil physical quality can facilitate diagnosis and decision-making. In this context, intrinsic soil air permeability (Kair) is a physical parameter very sensitive to structural changes due to soil management. However, it is important to establish a standard Kair, considering a reference soil physical state. Thus, the present study proposes to create an index called relative soil air permeability (Kairr), taking as reference the physical state of maximum bulk density, obtained by normal Proctor test. Kairr is the ratio between compacted soil air permeability (Kairc) and actual soil air permeability (Kair). Kairr was evaluated using disturbed and undisturbed samples of a Latossolo and a Planossolo. The experimental design was completely randomized, with four treatments (T1-Latossolo 0-0.1 m; T2-Latossolo 0.1-0.2 m; T3-Planossolo 0-0.1 m and T4-Planossolo 0.1-0.2 m) and eight replicates. Kairr was equal to 0.1032 and 0.3547 in the Latossolo and to 0.4115 and 0.1923 in the Planossolo, in the 0-0.1 and 0.1-0.2 m layers, respectively. These characteristic values observed in both soils and layers are due to the management adopted in the area. In Latossolo, the use of medium harrow has made the 0.1-0.2 m layer more restrictive to air movement, whereas the Planossolo showed lower values of relative soil air permeability in the 0-0.1 m layer due to animal grazing, which has greater impact on the superficial portion of the soil.