Dynamical and physical features of Perseid meteoroids from Tajikistan fireball network observations

2020 ◽  
Vol 494 (1) ◽  
pp. 1018-1026
Author(s):  
G I Kokhirova ◽  
P B Babadzhanov ◽  
U H Khamroev ◽  
M N Latipov ◽  
Sh B Faizov
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Meteor Shower ◽  
Light Curves ◽  
Optical Observations ◽  
Dust Trail ◽  
Annual Component ◽  
The Mean ◽  
Physical Features ◽  
Perihelion Passage

ABSTRACT We present the results of a study of the dynamical and physical properties of large-sized Perseid meteoroids based on optical observations. Photographic observations of the Perseid meteor shower were carried out during the maximum of its activity in 2007–2011 using the Tajikistan fireball network. Multistation images of 29 Perseids recorded during this period were processed. The atmospheric trajectories, velocities, radiants, orbits, photometric masses and densities of the meteoroids were determined using the astrometric and photometric reduction of fireball images. The initial masses of meteoroids that produced fireballs range from several to 20 g. The observed light-curves of the Perseids and the mean bulk density of most meteoroids of ~0.4 g cm−3 are typical for cometary matter. According to the radiants, velocities and orbits, the captured Perseids are related both to the annual component of the stream and to the dust trail ejected by the parent comet 109P/Swift–Tuttle during its last perihelion passage in 1992.

Growth of Container-grown Plants With and Without Azomite Soil Amendment

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 492c-492
Author(s):  
Chris Ely ◽  
Mark A. Hubbard
Keyword(s):  
Plant Growth ◽  
Physical Properties ◽  
Bulk Density ◽  
Soil Amendment ◽  
Extended Period ◽  
Mineral Elements ◽  
Field Soil ◽  
Rooted Cuttings ◽  
Sodium Calcium ◽  
Water Holding

Azomite is a mined, commercially available, hydrated sodium calcium aluminosiliclate soil amendment reported to act as a source of mineral elements. To determine its effect on plant growth, Dendranthema `Connie' rooted cuttings, Malus seedlings, and Citrus seedlings were grown in containers in one of two growing media: ProMix BX or ProMix BX with Azomite (1:1, v:v). Plant height was monitored weekly and after 6 weeks of growth, fresh and dry plant weights of roots and shoots were determined. There was no difference in any of the parameters measured as a result of the addition of Azomite. Any nutritional influence of the Azomite may only be evident in different conditions, e.g., field soil, or over an extended period of time. The Azomite altered the medium's physical properties and therefore bulk density and water-holding capacity of the Azomite were determined for consideration.

Measuring the Thermo-Technical Parameters of Autoclaved Aerated Concrete

2016 ◽  
Vol 824 ◽  
pp. 100-107 ◽  
Author(s):  
Alena Struhárová
Keyword(s):  
Thermal Conductivity ◽  
Moisture Content ◽  
Physical Properties ◽  
Bulk Density ◽  
Capillary Absorption ◽  
Measuring Device ◽  
Technical Parameters ◽  
Autoclaved Aerated Concrete ◽  
Aerated Concrete ◽  
Technical Properties

Bulk density and moisture content are factors that significantly affect the physical properties of autoclaved aerated concrete (AAC) including thermal conductivity and other thermo-technical characteristics. This article shows the results of measurements of compressive strength, capillary absorption, water absorption and porosity of AAC (ash on fluidized fly ash) at different bulk density and also the results of thermal conductivity of AAC at different bulk density and variable moisture content of the material. The thermo-technical properties were measured using the Isomet 2104, a portable measuring device. Acquired results demonstrate dependence of physical properties including thermal conductivity of AAC on bulk density and moisture content. The reliability and accuracy of the method of measuring was also shown.

PERSISTENCE OF CHANGES IN SELECTED SOIL CHEMICAL AND PHYSICAL PROPERTIES AFTER PIPELINE INSTALLATION IN SOLONETZIC NATIVE RANGELAND

1987 ◽  
Vol 67 (4) ◽  
pp. 747-763 ◽  
Author(s):  
M. A. NAETH ◽  
A. W. BAILEY ◽  
W. B. McGILL
Keyword(s):  
Organic Matter ◽  
Physical Properties ◽  
Bulk Density ◽  
Organic Matter Content ◽  
Matter Content ◽  
Chemical Changes ◽  
Ecosystem Responses ◽  
Native Prairie ◽  
Natural Gas Pipelines ◽  
Mixed Prairie

A study was conducted in Solonetzic mixed prairie of southern Alberta to evaluate and determine the longevity of selected ecosystem responses to pipeline installation. Five adjacent natural gas pipelines on a series of rights-of-way (ROW) were studied at three sites. The lines, which were installed in 1957, 1963, 1968, 1972 and 1981, had diameters of 86, 86, 91, 107 and 107 cm, respectively. Soils were analyzed for particle size distribution, bulk density, pH, electrical conductivity, ion composition, and organic matter content. It was concluded that pipeline construction in Solonetzic mixed prairie range-land initially tended to improve surface soil chemical and physical properties compared to blowouts, but reduced soil quality in vegetated native prairie. Surface bulk density increased to 1.3–1.6 Mg m−3 from an undisturbed density of 0.9–1.0 Mg m−3. Increased densities were evident to 55 cm in all 1981 transects except the trench where subsurface densities were reduced. Chemical changes were associated with reduced organic matter and increased salts at the surface. On the basis of differences between the various ages of pipelines (1981, youngest; 1957, oldest) there was evidence for greater amelioration of chemical changes than of physical disturbances over time. The time needed to restore half the lost organic matter was estimated to be approximately 50 y. Key words: Pipeline, Solonetzic soil, rangeland (native), soil chemistry, bulk density, reclamation

scholarly journals Understanding Type II Supernovae

2005 ◽  
Vol 192 ◽  
pp. 275-280 ◽  
Author(s):  
L. Zampieri ◽  
M. Ramina ◽  
A. Pastorello
Keyword(s):  
Physical Properties ◽  
Large Range ◽  
Simultaneous Analysis ◽  
Light Curves ◽  
Physical Parameters ◽  
Expansion Velocity ◽  
Type Ii ◽  
Strong Correlations ◽  
Systematic Analysis ◽  
Robust Estimates

SummaryWe present the results of a systematic analysis of a group of Type II plateau supernovae that span a large range in luminosities, from faint objects like SN 1997D and 1999br to very luminous events like SN 1992am. The physical properties of the supernovae appear to be related to the plateau luminosity or the expansion velocity. The simultaneous analysis of the observed light curves, line velocities and continuum temperatures leads us to robust estimates of the physical parameters of the ejected envelope. We find strong correlations among several parameters. The implications of these results regarding the nature of the progenitor, the central remnant and the Ni yield are also addressed.

scholarly journals Surface lime and silicate application and crop production system effects on physical characteristics of a Brazilian Oxisol

Soil Research ◽  
2017 ◽  
Vol 55 (8) ◽  
pp. 778
Author(s):  
G. S. A. Castro ◽  
C. A. C. Crusciol ◽  
C. A. Rosolem ◽  
J. C. Calonego ◽  
K. R. Brye
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Production System ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Crop Productivity ◽  
Soil Physical Properties ◽  
Physical Characteristics ◽  
Forage Crop

This work aimed to evaluate the effects of crop rotations and soil acidity amelioration on soil physical properties of an Oxisol (Rhodic Ferralsol or Red Ferrosol in the Australian Soil Classification) from October 2006 to September 2011 in Botucatu, SP, Brazil. Treatments consisted of four soybean (Glycine max)–maize (Zea mays)–rice (Oryza sativa) rotations that differed in their off-season crop, either a signal grass (Urochloa ruziziensis) forage crop, a second crop, a cover crop, or fallow. Two acid-neutralising materials, dolomitic lime (effective calcium carbonate equivalent (ECCE) = 90%) and calcium-magnesium silicate (ECCE = 80%), were surface applied to raise the soil’s base saturation to 70%. Selected soil physical characteristics were evaluated at three depths (0–0.1, 0.1–0.2, and 0.2–0.4 m). In the top 0.1 m, soil bulk density was lowest (P < 0.05) and macroporosity and aggregate stability index were greatest (P < 0.05) in the forage crop compared with all other production systems. Also, bulk density was lower (P < 0.05) and macroporosity was greater (P < 0.05) in the acid-neutralising-amended than the unamended control soil. In the 0.1–0.2-m interval, mean weight diameter and mean geometric diameter were greater (P < 0.05) in the forage crop compared with all other production systems. All soil properties evaluated in this study in the 0.2–0.4-m interval were unaffected by production system or soil amendment after five complete cropping cycles. Results of this study demonstrated that certain soil physical properties can be improved in a no-tillage soybean–maize–rice rotation using a forage crop in the off-season and with the addition of acid-neutralising soil amendments. Any soil and crop management practices that improve soil physical properties will likely contribute to sustaining long-term soil and crop productivity in areas with highly weathered, organic matter-depleted, acidic Oxisols.

scholarly journals Characterizing Soil Physical Properties for Soil Moisture Monitoring with the North Carolina Environment and Climate Observing Network

2012 ◽  
Vol 29 (7) ◽  
pp. 933-943 ◽  
Author(s):  
Weinan Pan ◽  
R. P. Boyles ◽  
J. G. White ◽  
J. L. Heitman
Keyword(s):  
North Carolina ◽  
Soil Moisture ◽  
Physical Properties ◽  
Soil Properties ◽  
Water Content ◽  
Bulk Density ◽  
Soil Physical Properties ◽  
The North ◽  
Wide Range ◽  
Soil Moisture Monitoring

Abstract Soil moisture has important implications for meteorology, climatology, hydrology, and agriculture. This has led to growing interest in development of in situ soil moisture monitoring networks. Measurement interpretation is severely limited without soil property data. In North Carolina, soil moisture has been monitored since 1999 as a routine parameter in the statewide Environment and Climate Observing Network (ECONet), but with little soils information available for ECONet sites. The objective of this paper is to provide soils data for ECONet development. The authors studied soil physical properties at 27 ECONet sites and generated a database with 13 soil physical parameters, including sand, silt, and clay contents; bulk density; total porosity; saturated hydraulic conductivity; air-dried water content; and water retention at six pressures. Soil properties were highly variable among individual ECONet sites [coefficients of variation (CVs) ranging from 12% to 80%]. This wide range of properties suggests very different behavior among sites with respect to soil moisture. A principal component analysis indicated parameter groupings associated primarily with soil texture, bulk density, and air-dried water content accounted for 80% of the total variance in the dataset. These results suggested that a few specific soil properties could be measured to provide an understanding of differences in sites with respect to major soil properties. The authors also illustrate how the measured soil properties have been used to develop new soil moisture products and data screening for the North Carolina ECONet. The methods, analysis, and results presented here have applications to North Carolina and for other regions with heterogeneous soils where soil moisture monitoring is valuable.

scholarly journals Optical observations of the Phoenicid meteor shower in 2014 and activity of comet 289P/Blanpain in the early 20th century

2017 ◽  
Vol 69 (4) ◽  
Author(s):  
Yasunori Fujiwara ◽  
Takuji Nakamura ◽  
Satoshi Uehara ◽  
Toru Sagayama ◽  
Hiroyuki Toda ◽  
...  
Keyword(s):  
20Th Century ◽  
Meteor Shower ◽  
Optical Observations ◽  
Early 20Th Century

scholarly journals Effect of Different Extrusion Processing Parameters on Physical Properties of Soy White Flakes and High Protein Distillers Dried Grains-Based Extruded Aquafeeds

2014 ◽  
Vol 3 (6) ◽  
pp. 107 ◽  
Author(s):  
Sushil K. Singh ◽  
K. Muthukumarappan
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Bulk Density ◽  
Water Solubility ◽  
Expansion Ratio ◽  
High Protein ◽  
Regression Equations ◽  
Process Variables ◽  
Distillers Dried Grains ◽  
Durability Index

<p>Nutritionally balanced ingredient blends for catla (<em>Catla catla</em>), belonging to the family Cyprinidae, were extruded using single screw extruder. The extrusion was carried out at five levels of soy white flakes content (21%, 29%, 40%, 52%, and 59% db), five levels of moisture content (15, 19, 25, 31, and 35% db) and five levels of barrel temperature (100, 110, 125, 140, and 150 ºC) using three different die nozzles (having L/D ratios 3.33, 5.83, and 7.25). Blends with net protein content of 32.5% contains soy white flakes, along with high protein distillers dried grains (HP-DDG), corn flour, corn gluten meal, fish meal, vitamin, and mineral mix. A central composite rotatable design (CCRD) and  response surface methodology (RSM) was used to investigate the significance of independent and interaction effects of the extrusion process variables on the extrudates physical properties namely pellet durability index, bulk density, water absorption and solubility indices and expansion ratio. Quadratic polynomial regression equations were developed to correlate the product responses and process variables as well as to obtain the response surfaces plots. The independent variables had significant (<em>P </em>&lt; 0.05) effects on physical properties of extrudates: (i) higher soy white flakes content increased the pellet durability index and water absorption index, but decreased the water solubility index, (ii) higher temperature decreased pellet durability index, bulk density and water solubility index, (iii) increased L/D ratio from 3.33 to 7.25 increased the pellet durability index, expansion ratio but decreased the bulk density of the extrudates.</p>

scholarly journals Does Mixing Tree Species Affect Water Storage Capacity of the Forest Floor? Laboratory Test of Pine-Oak and Fir-Beech Litter Layers

Forests ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1674
Author(s):  
Anna Ilek ◽  
Małgorzata Szostek ◽  
Anna Mikołajczyk ◽  
Marta Rajtar
Keyword(s):  
Physical Properties ◽  
Bulk Density ◽  
Tree Species ◽  
Forest Floor ◽  
Storage Capacity ◽  
Water Storage ◽  
Pine Needles ◽  
Litter Layer ◽  
Water Storage Capacity ◽  
Organic Debris

During the last decade, tree species mixing has been widely supported as a silvicultural approach to reduce drought stress. However, little is known on the influence of tree species mixing on physical properties and the water storage capacity of forest soils (including the forest floor). Thus, the study aimed to analyze the effect of mixing pine needles and oak leaves and mixing fir needles and beech leaves on hydro-physical properties of the litter layer during laboratory tests. We used fir-beech and pine-oak litter containing various shares of conifer needles (i.e., 0, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90 and 100%) to determine the influence of the needle admixture on bulk density, total porosity, macroporosity, water storage capacity, the amount of water stored in pores between organic debris and the degree of saturation of mixed litter compared to broadleaf litter (oak or beech). We found that the admixture of fir needles increased the bulk density of litter from 7.9% with a 5% share of needles to 55.5% with a 50% share (compared to pure beech litter), while the share of pine needles < 40% caused a decrease in bulk density by an average of 3.0–11.0% (compared to pure oak litter). Pine needles decreased the water storage capacity of litter by about 13–14% with the share of needles up to 10% and on average by 28% with the 40 and 50% shares of pine needles in the litter layer. Both conifer admixtures reduced the amount of water stored in the pores between organic debris (pine needles more than fir needles).

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