scholarly journals Simulation of The Effect of Libyan Sand on The Reflectance Surface of CSP

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
E Endaya
Keyword(s):  
Weather Conditions ◽  
Chemical Compositions ◽  
Particle Sizes ◽  
Large Area ◽  
Sand Blasting ◽  
Speed Variation ◽  
Different Types

The reflector characteristics are negatively affected by the harsh desert weather conditions and hence the performance of the system decreases. This paper investigates the effect of two different types of moving sands “A” and “B” from Libya on the performance and safety of the solar reflectors. Samples are collected from areas that are suitable for installing CSP plants. They are in different particle sizes and chemical compositions: sand “A” with size ranges between 0.025-0.355 mm, and “B” is within 0.124-0.479 mm. The experiment outcome using sand blasting indicated that sand “A” has more influence than sand “B” as thesmall particles of “A” spread over a large area of the reflector. It is also noticed in the range studied that the speed variation effect has more impact than the mass quantity changing. For clean surfaces, the reflectivity is dropped by 2.2%, and the damaged surfaces increased about 1 mm in case of 0.5 g mass at 27 m/s storm speed. For 2g mass at 21 m/s storm speed, the roughness is found 3 mm.

scholarly journals Size-segregated characteristics of organic carbon (OC), elemental carbon (EC) and organic matter in particulate matter (PM) emitted from different types of ships in China

2020 ◽  
Vol 20 (3) ◽  
pp. 1549-1564 ◽  
Author(s):  
Fan Zhang ◽  
Hai Guo ◽  
Yingjun Chen ◽  
Volker Matthias ◽  
Yan Zhang ◽  
...  
Keyword(s):  
Particle Size ◽  
Elemental Carbon ◽  
Fine Particles ◽  
Particle Mass ◽  
Fuel Oil ◽  
Chemical Compositions ◽  
Particle Sizes ◽  
Heavy Fuel Oil ◽  
Different Types ◽  
Marine Diesel

Abstract. Studies of detailed chemical compositions in particles with different size ranges emitted from ships are in serious shortage. In this study, size-segregated distributions and characteristics of particle mass, organic carbon (OC), elemental carbon (EC), 16 EPA polycyclic aromatic hydrocarbons (PAHs) and 25 n-alkanes measured aboard 12 different vessels in China are presented. The results showed the following. (1) More than half of the total particle mass, OC, EC, PAHs and n-alkanes were concentrated in fine particles with aerodynamic diameter (Dp) < 1.1 µm for most of the tested ships. The relative contributions of OC, EC, PAH and alkanes to the size-segregated particle mass are decreasing with the increase in particle size. However, different types of ships showed quite different particle-size-dependent chemical compositions. (2) In fine particles, the OC and EC were the dominant components, while in coarse particles, OC and EC only accounted for very small proportions. With the increase in particle size, the OC / EC ratios first decreased and then increased, having the lowest values for particle sizes between 0.43 and 1.1 µm. (3) Out of the four OC fragments and three EC fragments obtained in thermal–optical analysis, OC1, OC2 and OC3 were the dominant OC fragments for all the tested ships, while EC1 and EC2 were the main EC fragments for ships running on heavy fuel oil (HFO) and marine-diesel fuel, respectively; different OC and EC fragments presented different distributions in different particle sizes. (4) The four-stroke low-power diesel fishing boat (4-LDF) had much higher PAH emission ratios than the four-stroke high-power marine-diesel vessel (4-HMV) and two-stroke high-power heavy-fuel-oil vessel (2-HHV) in fine particles, and 2-HHV had the lowest values. (5) PAHs and n-alkanes showed different profile patterns for different types of ships and also between different particle-size bins, which meant that the particle size should be considered when source apportionment is conducted. It is also noteworthy from the results in this study that the smaller the particle size, the more toxic the particle was, especially for the fishing boats in China.

scholarly journals Fundamental Parameters and Models of Stellar Atmospheres

1985 ◽  
Vol 111 ◽  
pp. 303-329
Author(s):  
Bengt Gustafsson ◽  
Uffe Graae-Jørgensen
Keyword(s):  
Model Atmosphere ◽  
Stellar Atmospheres ◽  
Chemical Compositions ◽  
Fundamental Parameters ◽  
Different Types ◽  
Effective Temperatures

The use of photometric and spectroscopic criteria, calibrated by model-atmosphere calculations, for determining effective temperatures, surface gravities and chemical compositions of stars is illustrated and commented on. The accuracy that can be obtained today in such calibrations is discussed, as well as possible ways of improving this accuracy further for different types of stars.

Large Area Surface Treatment by Ion Beam Technology

1996 ◽  
Vol 438 ◽  
Author(s):  
R. L. C. Wu ◽  
W. Lanter
Keyword(s):  
Ion Beam ◽  
High Vacuum ◽  
Polycrystalline Diamond ◽  
Carbon Films ◽  
Ultra High Vacuum ◽  
Diamond Like Carbon ◽  
Chemical Compositions ◽  
Rf Power ◽  
Large Area ◽  
Ion Energy

AbstractAn ultra high vacuum ion beam system, consisting of a 20 cm diameter Rf excilted (13.56 MHz) ion gun and a four-axis substrate scanner, has been used to modify large surfaces (up to 1000 cm2) of various materials, including; infrared windows, silicon nitride, polycrystalline diamond, 304 and 316 stainless steels, 440C and M50 steels, aluminum alloys, and polycarbonates; by depositing different chemical compositions of diamond-like carbon films. The influences of ion energy, Rf power, gas composition (H2/CH4 , Ar/CH4 and O2/CH4/H2), on the diamond-like carbon characteristics has been studied. Particular attention was focused on adhesion, environmental effects, IR(3–12 μm) transmission, coefficient of friction, and wear factors under spacelike environments of diamond-like carbon films on various substrates. A quadrupole mass spectrometer was utilized to monitor the ion beam composition for quality control and process optimization.

Abrasive Wear Research on Rubber

1961 ◽  
Vol 34 (2) ◽  
pp. 482-492 ◽  
Author(s):  
K. Wellinger ◽  
H. Uetz
Keyword(s):  
Abrasive Wear ◽  
Abrasion Resistance ◽  
Testing Methods ◽  
Sand Blasting ◽  
Testing Conditions ◽  
Different Types ◽  
Paper Method ◽  
Abrasive Paper ◽  
Blasting Method

Abstract The abrasion resistance of five different types of rubber were compared with steel (St 37) by various testing methods, such as the abrasive paper method, the abrasion cup method and the sand blasting method. The order of resistance of the various types of rubber against sand blasting is different from the order which is obtained with the sandpaper and abrasion cup methods. However, variations of the testing conditions within one method generally does not change the order. It has been shown, that rubber is more resistant against sand blasting than other materials investigated (basalb, malleable steel, non-alloyed hard castings) if the sand blast is directed essentially perpendicularly against the tested surface.

scholarly journals Influences of different curing methods on chemical compositions in different types of tobaccos

2021 ◽  
Vol 167 ◽  
pp. 113534
Author(s):  
Jie Chen ◽  
Yan Li ◽  
Xian He ◽  
Fangchan Jiao ◽  
Meiling Xu ◽  
...  
Keyword(s):  
Chemical Compositions ◽  
Different Types ◽  
Curing Methods

The growth of supernumerary legs in the cockroach

Development ◽  
1986 ◽  
Vol 92 (1) ◽  
pp. 115-131
Author(s):  
Paul R. Truby
Keyword(s):  
Wound Healing ◽  
Cell Division ◽  
Rapid Rate ◽  
Large Area ◽  
Anteroposterior Axis ◽  
Cell Divisions ◽  
Leucophaea Maderae ◽  
Different Types ◽  
Local Cell

When the anteroposterior axis of a cockroach leg is reversed at a graft by exchanging a left leg for a right leg at the mid-tibia level, regeneration occurs in the region of the graft/host junction. This results in the formation of a pair of lateral supernumerary legs. In these experiments the patterns of cell division which take place during supernumerary leg formation were observed in sections of regenerating legs of the cockroach Leucophaea maderae. Early patterns of cell division resemble those seen in control grafts in which no axial reversal had been carried out during grafting. These cell divisions are associated with the process of wound healing. Later, a large area of the epidermis proximal to the graft/host junction becomes activated and shows a rapid rate of cell division. This area forms two outgrowths which grow by cell division throughout their epidermis to form the epidermis of the supernumerary legs. The results are more consistent with the view that the formation of supernumerary legs involves dedifferentiation of the epidermis in the region of the graft/host junction to form a blastema, rather than being due to local cell division at the point of maximum pattern discontinuity. This conclusion is used to offer an explanation for the range of different types of outcome of left-right grafts that has been observed.

scholarly journals The Review of Chemistry, Pharmacology and Processing Method of Rhubarb (Rheum species)

2019 ◽  
Vol 8 ◽  
Author(s):  
Jingwen He ◽  
Liang Wang ◽  
Hongxing Guo ◽  
Hui Zhao ◽  
Jiachen Sun
Keyword(s):  
Blood Circulation ◽  
Processing Method ◽  
The Body ◽  
Chemical Compositions ◽  
Pharmacological Activities ◽  
Processing Methods ◽  
Traditional Medicines ◽  
Toxic Materials ◽  
Different Types ◽  
Body Cooling

Rhubarb is one of the Chinese traditional medicines. About ninety-four compounds with five different types of skeletons (anthraquinone, anthrones, stilbenes, flavonoids and acylglucosides) have been isolated from rhubarb so far. These constituents are effective in purgative, clearing heat-fire, removing toxic materials from the body, cooling blood and promoting blood circulation. Recent studies have shown that the appropriate processing methods may directly impact on its nutraceutical activities and chemical compositions. Here, we summarize the update progress in the chemical compositions, pharmacological activities and processing methods of rhubarb.

scholarly journals A general database of hydrometeor single scattering properties at microwave and sub-millimetre wavelengths

2018 ◽  
Author(s):  
Patrick Eriksson ◽  
Robin Ekelund ◽  
Jana Mendrok ◽  
Manfred Brath ◽  
Oliver Lemke ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Single Scattering ◽  
Particle Orientation ◽  
Maximum Diameter ◽  
Particle Sizes ◽  
Orientation Data ◽  
Different Types ◽  
Rain Drops ◽  
Cloud Ice ◽  
Random Particle

Abstract. A main limitation today in simulations and inversions of microwave observations of ice hydrometeors (cloud ice, snow, hail ...) is the lack of data describing the interaction between electromagnetic waves and the particles. To improve the situation, the development of a comprehensive dataset of such "scattering properties" has been started. The database aims at giving a broad coverage in both frequency (1 to 886 GHz) and temperature (190 to 270 K), to support both passive and active current and planned measurements, and to provide data corresponding to the full Stokes vector. This first version of the database is restricted to totally random particle orientation. Data for 34 particle sets, i.e. habits, have been generated. About 17 of the habits can be classified as single crystals, three habits can be seen as heavily rimed particles, and remaining habits are aggregates of different types, representing e.g. snow and hail. The particle sizes considered vary between the habits, but a maximum diameter of 10 and 20 mm are typical values for the largest single crystal and aggregate particles, respectively, and the number of sizes per habit is at least 30. Particles containing liquid water are also inside the scope of the database, but this phase of water is so far only represented by a liquid sphere habit. The database is built upon the netCDF4 file format. Interfaces to browse, extract and convert data for selected radiative transfer models are provided in Matlab and Python. The database and associated tools are publically available from Zenedo (https://doi.org/10.5281/zenodo.1175572 and https://doi.org/10.5281/zenodo.1175588, respectively). Planned extensions include non-spherical rain drops, melting particles and a second orientation case that can be denoted as azimuthally random.

scholarly journals Reclaiming land flooded with salt water.

1953 ◽  
Vol 1 (4) ◽  
pp. 225-244
Author(s):  
C.W.C. Beekom
Keyword(s):  
Salt Concentration ◽  
Sea Water ◽  
Salt Water ◽  
Soil Layer ◽  
Weather Conditions ◽  
Phleum Pratense ◽  
Active Growth ◽  
Warm Weather ◽  
Different Types ◽  
Spring Sowing

The effect of sea floods on grassland is described and recommendations are made for the restoration of inundated grassland. Turf may be heavily damaged after +or- 4 weeks inundation with water containing more than 20 g. NaCl per 1. At lower salt concentrations Poa sp. and Trifolium repens are still badly damaged but other species, notably Lolium perenne, Agrostis stolonifera and Alopecurus sp., are capable of immediate regrowth after drainage. If grassland remains submerged during spring, rising temperatures promote active growth of the grasses followed by rapid decay caused by lack of oxygen. L. perenne is especially sensitive to submergence in warm weather. The dominant weed communities which appear on land on which the turf has been destroyed by sea-water are described. Reseeding is recommended as the quickest method of restoring badly damaged turf. The flooded land should first be thoroughly drained and then repeatedly harrowed to produce a shallow seed-bed on which herbage mixtures can be sown without the application of gypsum. Given average weather conditions, normal permanent grassland mixtures can be sown at salt concentrations, measured in spring, of up to 8-10 g. NaCl per 1. of moisture in the 5-20 cm. soil layer. At a salt concentration of about 10 g. per 1. measured in spring, L. perenne tends to dominate over other species while Poa sp. and T. repens suffer during the summer. At a salt concentration of 10-15 g. per 1. in spring, Poa sp. and T. repens should be omitted from seed mixtures, instead mixtures consisting of different types of L. perenne, Festuca pratensis and Phleum pratense should be sown. When the salt concentration of the soil moisture is higher that 15 g. per 1. in spring, sowing should be delayed and the weeds checked by mowing or grazing. Temporary rises of the salt concentration in dry symmers to 25 g. per 1. are tolerated by L. perenne, F. pratensis and Ph. pratense; similar rises up to 15-18 g. per 1. are tolerated by Poa sp. and T. repens.-W.J.B. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Evaluation of Selected Performance Properties of Nanoclay-Modified Asphalt Binders

2019 ◽  
Vol 271 ◽  
pp. 03006
Author(s):  
Mohammad N. Hassan ◽  
M M Tariq Morshed ◽  
Zahid Hossain
Keyword(s):  
Colloidal Stability ◽  
Asphalt Binder ◽  
Weather Conditions ◽  
Good Alternative ◽  
Asphalt Binders ◽  
Chemical Compositions ◽  
Modified Asphalt ◽  
Adverse Weather ◽  
Modified Asphalt Binder ◽  
Improved Performance

Asphalt binders are often modified with additives such as acid, polymer, or a combination of multiple additives to achieve improved performance to sustain heavy loads and adverse weather conditions. According to some previous researches, nanoclay can be a good alternative of currently practiced Styrene-Butadiene-Styrene (SBS) modification, and the former is expected to reduce the overall cost of the asphalt binder. Three types of nanoclay (Cloisite 10A, 11B, and 15A) were blended with asphalt binders prepared from two different sources (Arabian Crude and Canadian Crude). A blending protocol has been developed to blend nanoclay with the base binders. Mechanical properties including viscosity, rutting parameter have undergone significant changes after the nanoclay modification. It was also observed that nanoclay modified binders offer different moisture susceptibility while bonding with different aggregates; the nanoclay modified asphalt binder exhibits better bonding with gravel than sandstone. Mechanistic properties such as viscosity and rutting parameter are found to be highly correlated with the chemical compositions. Binders from the Canadian crude showed more colloidal stability than binders from the Arabian crude after nanoclay modification.

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