Apparent Specific Weight Research Articles

Evaluation of the Structure of Dry Soil, Subjected to Dynamic Load in Different Managements

The structural evaluation of agricultural soil is essential for the performance and quality of production. Soils suffer surface consolidation when subjected to agricultural machinery traffic and alter their physical characteristics according to the management to which it is subjected. Therefore, this work aimed to evaluate the physical indices and surface consolidation of a red oxisol subjected to different loads and types of management. Undeformed soil samples were collected from three areas with different management systems: no-tillage, crop-livestock--forest integrated system (CLFI), and pasture area. Traffic simulations were conducted with application of dynamic loads, using 0 pass, 1 pass, and 2 passes (0, 108, and 216 kpa), evaluating the physical indices of the soil's natural specific weight (yn), dry apparent specific weight (yd), void index (n), and porosity (e). Subsequently, the samples were subjected to uniaxial compression tests using loads (108, 216, 432, 864, and 1500 Kpa) to verify the surface consolidation. The experiment was conducted in a completely randomized design, with a 3x3x5 factorial scheme in sub-subdivided plots. Thus, we verified that the no-tillage management system has a more porous soil due to its characteristics, presenting lower resistance and being better for planting. CLFI was characterized as a management that allowed the soil to be more resistant to the application of loads and, therefore, less porous. Pasture has an intermediate behavior.

Study of Various Mechanical Properties of Maize (Zea mays) as Influenced by Moisture Content

The mechanical properties of agricultural materials influence not only the loads occurring inside agricultural silos, but also the design of several types of post-harvest machinery. The loads generated by these materials inside silos can be predicted with silo calculation methodologies from their mechanical properties. It has been known for many years that these properties are highly dependent on the moisture content of the material. However, to date, there are not many studies focused on its determination. The goal of this research is the determination of the internal friction angle, apparent cohesion, angle of dilatancy and apparent specific weight of maize when different moisture contents are applied. The equipment used for this study consisted mainly of direct shear and oedometer assay apparatus. The maize samples used were moistened using a climatic chamber. Moisture contents applied to maize samples ranged from 9.3% to 17.4%. Results similar to those provided by other authors were obtained for the internal friction angle, apparent cohesion and apparent specific weight. On the other hand, the values obtained for the dilatancy angle of maize as a function of moisture content could not be compared because nothing has been published so far. The values obtained for this parameter overlap with those published for this material under ambient conditions. In addition, for the samples tested, these results did not allow confirming the existence of a direct relationship between the dilatancy angle and the moisture content. Finally, the increase in moisture content led to an increase in apparent specific weight, which differed from that published in the literature. The values provided here can be used for the optimization of storage and handling structures for granular agricultural materials.

Influence of Moisture Content on Some Mechanical Properties of Wheat

The loads generated inside agricultural silos under static and dynamic conditions depend on the mechanical properties of the materials stored inside them. Silo calculation methodologies are based on these mechanical properties. Although it is known that moisture content greatly influences the values reached by these mechanical properties, only a few studies have been conducted to determine them. The present work determines the angle of internal friction, the apparent cohesion, the dilatancy angle and the apparent specific weight of wheat when subjected to different moisture contents. Direct shear and oedometer assay devices were used. In addition, a climatic chamber was used to moisten the wheat samples used in this work. From the different assays conducted, it could be observed that the values of the angle of internal friction, the apparent cohesion and the apparent specific weight were like those found in the literature. However, no values of the dilatancy angle of wheat as influenced by moisture content were previously reported. The values obtained here for this parameter are within the range of those specified for dry wheat samples. Finally, higher apparent specific weight values were observed as moisture content increased up to 13.4%, then decreasing at a moisture content of 15.5%. This was not expected according to the results stated by some authors, although others reported a similar tendency. The values here provided can be used in silo load calculations involving numerical methods for modeling technological processes.

Characterisation of cementitious composite materials based on calcined clay activated by silicate from rice husk ash and Ingessil silicate - activator: sodium hydroxide (NaOH)

The ever-increasing cost of cement and its production of harmful carbone dioxide (CO2) has led development actors to continuously search for less environmentally polluting and low-cost binders. Hence the interest in the valorisation of agricultural resources through the production of different binders such as silicate for the elaboration of geopolymers at low manufacturing temperatures (<100 °C). In this study, Ingessil industrial silicate and rice husk ash silicate were used as pozzolan raw materials to prepare geopolymers with sodium hydroxide as activator at a concentration of 12 M. Two types of samples were developed: geopolymer mortars based on Ingessil silicate and geopolymer concretes based on Ingessil industrial silicate and rice husk ash silicate. Sand and gravel were used as fine and coarse aggregates for the production of geopolymer concretes. They were represented 80% of the mass of the geopolymer concretes according to the standards of elaboration.The porosity values obtained were of the order of 30%, i.e. water absorption values of about 18%, apparent specific weight of about 5% and bulk density of 1.7%. The mechanical values of BGAC-RHA samples are higher than those of BGAC-I. The physico-chemical properties of geopolymer mortars and concretes were similar.

Validity of Euphrates River Terraces Deposits between Baghdad and Fallujah for Concrete Works

Four sites for deposits between Baghdad and Fallujah were studied. The results showed that all sites conform to the limits of the American Standard Specifications ASTMC33-03 and British Standard Specifications for Building Materials. As for Sieve Analysis for the coarse aggregate, the results for the first and fourth sites correspond to the nominal size of 4.75-19mm, with a deviation at the particle size of 19mm in the second and third sites. The apparent specific weight values ranged between 2.72-2.75 g/cm3 for fine aggregate and between 2.63-2.64 g/cm3 for coarse aggregate. While the rate of absorption was 1.40-1.63% for fine aggregates and 0.60-1.26% for coarse aggregates. The percentage of fine materials ranged between 1.58-4.51% for fine aggregates and 0.79-1.71% for coarse aggregates. The percentage of clay blocks and friable materials was 2.31-12.09% for fine aggregates and 0.39-1.55% for coarse aggregates. The percentage of lightweight materials is between 0.30-0.58% for fine aggregates and 0.24-0.48% for coarse aggregates. The flatness ratio of coarse aggregates ranged between 11.9-13.4% and the elongation ratio between 16.3-20.7%. The percentage of Soundness ranged between 5.56-7.46% for fine aggregates and between 3.14-5.88% for coarse aggregates. The chemical results were within the limits of the standard specifications. One of the most essential recommendations of the current study is to wash the fine and coarse aggregates with water well before use in concrete works should be considered to get rid of impurities, harmful substances, and salts.

Values for the Mechanical Properties of Wheat, Maize and Wood Pellets for Use in Silo Load Calculations Involving Numerical Methods

The mechanical properties of the materials stored in agricultural silos determine the loads they generate under static and dynamic conditions. The present work describes the mechanical properties of wheat, maize and wood pellets. Direct shear and triaxial assay devices, and oedometers (all commonly used in geotechnical assays), were used to determine these materials’ internal angle of friction, Poisson’s ratio, Young’s modulus, apparent specific weight, etc. The results for wheat and maize were similar to those previously reported by other authors. For the wood pellets, the results for the internal angle of friction and apparent specific weight were also similar to those found in the literature. However, this is a relatively new type of material, and few results of this type have been reported, certainly not enough for reference values to be available. This work is the first to report this material’s dilatancy angle and Poisson’s ratio. A table is provided with suggested reference values for the studied mechanical properties of each of the test materials; these can be used in silo load calculations involving numerical methods.

Ceramic bricks containing Ni ions from contaminated biomass used as an adsorbent

This article shows how pine sawdust residues can be used to adsorb nickel ions from synthetic solutions and then to produce porous bricks for civil construction using a mixture of natural clay and biomass containing the adsorbed metals. The adsorption tests were performed by mixing NiCl2 solutions with pine sawdust during a fixed stirring period of 24 h. The set was filtered and the filtrate was analysed. Highest efficiency adsorbate/adsorbent ratio was 50 mL of 1 M NiCl2 solution and 20 g L− 1 of pine sawdust. This was the contaminated biomass sample used in the manufacture of the bricks. This paper analyses the properties of the bricks achieved and compares them with bricks without added biomass, porous bricks containing zinc and commercial bricks. The obtained values of bulk density, apparent specific weight, apparent porosity, water absorption, apparent volume, weight loss on ignition, compressive strength, flexural modulus of rupture and efficiency retention of metal in the brick, demonstrate that the ceramic pieces obtained are optimal for construction.

Quad bike impacts on vegetation and soil physicochemical properties in an arid ecosystem

The increase use of Off-Road Vehicles (ORVs) coupled with the absence of control strategies have led to extensive use of natural areas for the creation of recreational trails. We assessed the effects of quad bikes on vegetation and soils in an arid ecosystem subjected to intensive quad bike use. We selected randomly eight traffic sites (disturbed sites) and eight adjacent control sites (undisturbed sites). Plant cover and composition were assessed with the point-intercept method and phytosociological census. In each site, we collected soil samples to assess soil physicochemical properties, including apparent specific weight (ASG), actual specific weight (RSG), porosity, texture, electric conductivity (EC) and pH. Soil compaction was measured at 30 spaces points per site. Plant cover and richness was significant lower in disturbed sites, with only four species present in areas subjected to disturbance. There were also changes in species dominance, with native perennial shrubs and grasses characterizing the undisturbed sites while the disturbed sites were mainly dominated by the invasive exotic herb Salsola kali. ORVs traffic also affected soil physicochemical properties including soil compaction, ASG, EC and soil pH. Soil compaction was more than double in disturbed sites and ASG tended to be higher under this condition. The EC was significantly higher and soil pH was significantly lower in the disturbed sites. Reduced vegetation cover and changes to soils physicochemical properties on quadbike trails highlights the impacts of ORVs in the landscape and the need to develop management strategies to minimize disturbance from ORVs on vegetation and soils.

Application of hybrid modified UASB - MBBR technology for wastewater treatment of Sao Thai Duong Pharmaceuticals and Cosmetics Factory

Wastewater of Sao Thai Duong Pharmaceuticals & Cosmetics Factory contains high concentration (more than 1000 mg/l) COD and BOD. Besides, some persistent substances are also found such as surfactants, emulsion oil and ammonium. Especially, the quite low BOD/COD ratio of 0.3 makes the treatment process of organic matters more complicated. Furthermore, the troublesome settlement of oil emulsions inhibits the wastewater biological treatment process which results in difficulties for selection of a stable and sustainable technology. For these reasons, it is recommended to use the Upflow Anaerobic Sludge Blanket Filtration (UASB) technique combined with the use of the bio-logical named carriers DHY-01 and DHY-02 (produced by Vinse Company). DHY carriers have a high porosity (92-96%), large surface area (10000-12000 m2) and apparent specific weight of 33 g/l. The anaerobic treatment tank (Upflow Blanket Filter - UBF) has a retention time of 10-12 hours. Influent COD concentration is about 1000-2000 mg/l, reduced by 65-70% after treatment. Influent BOD concentration is 200-600mg/l, reduced by about 60-65% after treatment. Aerobic tank (moving bed biofilm reactor - MBBR) has a retention time of 4-6 hours. COD and ammonium removal efficiency is about 85-90%.

Evaluation of Some Traits in Local Iranian Quince (Cydonia Oblonga Miller) Genotypes

ABSTRACTQuince (Cydonia oblonga Miller.) belongs to the Rosaceae family and is generally used for fresh consumption and processed items. In this research, fruit characteristics of eight quince genotypes from Iran were investigated via genotype by trait interactions (GTI) biplot. Results indicated that the first two principal components analysis (PC1 and PC2) were used to create a two-dimensional GTI biplot that accounted percentages of 31% and 22%, respectively, of sums of squares of the GTI. The vertex genotypes in polygon were Svs1, Esf, Nb1, Kud2 and Et1; and Svs1 was the winning genotype for pectin, fruit length, phosphorus percent and fruit hardness while Esf was the best genotype for iron percent, fruit diameter, fruit weight and end hold. There were positive correlation among pectin, fruit length, fruit hardness and phosphorus percent as well as among zinc percent, branch length, fruit apparent specific weight, calcium percent and potassium percent. Genotype Svs1 was more desirable followed by genotypes Nb4, Esf and Et1 based on ideal entry biplot and pectin and fruit length were the best traits according to ideal tester biplot. The best genotype for obtaining of high fruit weight was Esf following to Nb4, Svs1 and Nb1 and ranking traits based on fruit weight showed that fruit diameter is more important followed by end hold and iron percent. This study showed that there was relatively high level of variation in quince genotypes grown and morphological traits used in this research indicating that they can be used for characterization and diversity analysis of quince. We concluded from this study that it is imperative for breeders to pay more attention to improve quince morphological traits coordinated to fruit yield performance.

Ozone saturation and decomposition kinetics in porous medium containing different hybrids of maize

ABSTRACT The objective of this study was to evaluate ozone saturation and decomposition kinetics in porous medium containing grains of different hybrids of maize. The following hybrids were used: common maize hybrid AG 1051, super sweet maize hybrids Tropical Plus, GSS 42072, GSS 41499 and GSS 41243. 1 kg grain samples with water contents of 13.0% (w.b.) were placed in glass containers with 3.25 L capacity. The grains were ozonized at the concentration of 1.28 mg L-1, at 25 ºC, with gas flow rate of 5.0 L min-1. Saturation time and concentration, half-life time and physical properties such as apparent specific weight, actual specific weight, porosity, sphericity and circularity of each maize hybrid were determined. The experiments were conducted in a completely randomized design with three replicates, using regression analysis of the data. Ozone saturation times remained between 6.6 and 163.9 min, with saturation concentration varying from 0.34 to 1.12 mg L-1. As for the ozone half-life time, the highest value was 10.5 min for the common maize hybrid AG 1051 and the lowest value was 0.14 min for the super sweet maize hybrid GSS 41499. It was concluded that ozone saturation and decomposition kinetics in maize depends on the hybrid contained in the porous medium. Ozone decomposition is faster in porous medium containing super sweet maize hybrids compared with the common maize hybrid.

Natural Durability and Apparent Specific Weights of Acrocarpus fraxinifolius Wight & Arn (Pink Cedar) Cultivated in the Province of Misiones, Argentina.

The objectives of this study were to explore the natural durability of heartwood and sapwood facing the action of the fungus Laetiporus sulphureus BAFC: 205, and also to determinetheapparent specific weightsof twelve years old Acrocarpus fraxinifolius Wight & Arn tree woods (Pink cedar), grown in Misiones, Argentina. The selected trees werefelledand sectionedinto logs, then sawed into strips from which the samples were obtained in order to carry out the durability testing following the modified European Norm No 113, and the apparent specific weight using theIRAM Argentine Norm No.9544. The results showed that heartwood is non-resistant, sapwood is perishable, and also according to the apparent specific weight it must be classified as half-heavy wood.We conclude that the A. fraxinifolius wood can be used mainly for interior constructions and for furniture.

Buckling of Masts of Bamboos Bundles

Bamboos generally have elasticity module in compression of about 9 GPa, which is a relatively low value compared to timber and concrete, 20 GPa, and steel, 200 GPa. However, the compressive strength is high - 40 to 80 MPa – that, combined with axissimetria of the cross section, makes the bamboos structural elements with high strength and flexibility. Considering the low apparent specific weight of the material 8 kN/m3, photosynthetic production and workability, bamboos have no competitor in the market so that loads can be absorbed independently by any of the above materials. But the industrial structural elements may be produced with dimensions and geometries provided in accordance with the load to be transported. This is not the case of bamboo. Thus, the capacity of the bamboo in compression becomes limited by its natural flexural rigidity, EI. Thus, different structural systems with pipe threads to make large columns or masts were investigated, [1,2], all with bamboo Phyllostachys pubescens species. In this paper, a kind of mast composed of a central bamboo 6 m in length and six smaller segments axi-symmetrically distributed around this central bamboo will be presented. This proposed design is organizationally a set of bars shackled by steel bands along the length of the beam. Flexion-compression tests with bamboo species Phyllostachys pubescens, combined with numerical modeling through the MEF were made. The loading capacity was tripled and the lateral deviations are negligible when compared with the axial bamboo tested alone. This mast, while consuming a relatively high number of bamboo units, has the advantages of ease and constructive possibility of structural use of smaller diameter bamboo. All the design and results of experimental and numerical analyzes will be discussed in this paper.

5600028 Method for producing lower polyhydric alcohols and a new ruthenium-based catalyst used in this method

A ruthenium-based hydrogenation catalyst, particularly but not exclusively for hydrogenolysis under pressure of higher polyhydric alcohols, comprises ruthenium supported on granular activated carbon, and has: a specific surface area of from 600 to 1000 m2 /g; a total pore volume of from 0.5 to 1.2 cm3 /g; an apparent specific weight (bulk density) of from 0.45 to 0.55 g/cm3 ; an actual specific weight of from 1.9 to 2.3 g/cm3 ; a total volume of micropores having a radius smaller than 75 A of from 0.4 to 0.55 cm3 /g; and an ash content of from 2 to 5% by weight. The catalyst is used in a method for the continuous production of lower polyhydric alcohols in a fixed bed reactor, by means of hydrogenolysis under pressure of higher polyhydric alcohols.

Effect of hydrothermal treatment in the presence of salts on the chromatographic properties of silica gel

The effects of hydrothermal treatment of silica gel in the presence of some inorganic salts on the chromatographic properties of the product have been studied. In addition to the specific surface area and the mean pore diameter, the selectivity and retention properties of the treated silica gel as well as some hydrodynamic properties are also changed. The extent of these changes depended both on the duration of the hydrothermal treatment and on the nature of the salt added. The treatment with phosphate ion solution produced a decrease in the specific pore volume and in the apparent specific weight of the silica gel skeleton, along with significant changes in its selectivity.

Oscillation of a Drop Hanging from a Tube

Oscillation of a drop hanging from a tube is investigated both theoretically and experimentally. The period of oscillation is obtained based on the assumption that the apparent specific weight, which is defined as the sum of the actual force and the inertial force per unit volume minus the force due to the surface tension, is unifrom at each time in the drop. The results agree well with experimental values obtained by high-speed photography.

空気分級における分級精度について

The classification method by pneumatic sieve has been developed to eliminate fines in ores charged into blast furnaces. When particles are supplied into air stream upward, smaller particles float up and larger one sink down. In this method, the apparent specific weight, the drag ccefficient of the particles, and the interference of moving particles in the air stream (especially between floating-up and sinking-down particles) affect the classification accuracy.In this paper, the above effects are experimentally and theoretically discussed. Conclus: ons are as follows;(1) The classification by pneumatic sieve is available with the difference of floating velocity of particles, even if apparent specific weight and drag coefficient scatter in some extent.(2) The scattering of apparent specific weight and drag coefficient affects the classification accuracy significantly for the particles of diameter nearly equal to the floating particle diameter Ds and negligibly for the particles of diameter less than half of Ds.(3) For the classification of particles in the same particle size distribution, the weight ratio in each size range of floating-up particles to supplied one decreases logarithmically with increasing mixing ratio M.

Radioactive methods for the quantitative determination of coastal drift rate

This paper presents the possibilities of a new method, known as the “count rate balance”, for the quantitative evaluation of coastal drift. It is based on conventional radioactive tracer experiments to which are applied space integration measurements. The “count rate balance” operation consists of the determination, from the family of isocount curves, of the total number of counts detectable over the radioactive patch as a whole: N = ▪ s n ds A relationship in fact exists between the burial depth of the layer of tracer immersed and the count rate measured at the surface. Because of the absorption of radiation, this activity gives fewer counts the more deeply it is buried. It also depends on the response of the probe, which is calibrated in the laboratory. This response takes the form: f=f o e−αz where α and f 0 are the calibration coefficients, z the depth at which the layer is buried, f is expressed in counts for 1 μ Ci/m 2 at a depth z. From the equation: 1 β × α f o × N A ×E=1− e αE where A is the total activity injected and N calculated from readings taken on the site; E is deduced graphically or by successive approximations. Once the thickness of the layer in movement is known, the solid displacement rate can be calculated from the formula: Q=ϱV m E where ϱ is the apparent specific weight of the sediment, E the thickness of the layer in movement, V m the mean transport velocity, and Q the drift rate for a 1 m width perpendicular to the direction of transport. This method was applied to a radioactive tracer experiment carried out on April 20, 1967 on the Roussillon coast (southwestern France) by immersion of 4.2 kg of natural sediment labelled with 10 Ci of chromium 51 (half-life 27.8 days), at a depth of 4 m between two folds in the sea bed. The transport was governed by two dominant types of wind and swell conditions. From April 20 to 29, swells from the north led to a southward displacement of about 1.05 tons/day/linear metre. From May 5 onward, south-southeast swells caused a northward movement reaching 1.43 tons/day per linear metre. Since the displacement rate is mainly a function of the thickness of the layer in movement, the results were checked by core samplings carried out by aqualung. The burial depths given by the core samples, although close to these found by calculation, only have a point value and are not a good illustration of the overall phenomenon. The method could enter into regular use after comparisons with other methods. In fact it has the advantage of requiring no special equipment apart from that needed in conventional radioactive tracer experiments, and no sampling is necessary.