Automation of the measurement of time record in determining the hydraulic conductivity of saturated soil

ABSTRACT The objective of this study was to automate the acquisition of water travel time, as well as the computation of hydraulic conductivity of saturated soil by the falling head method, using water sensors and the Arduino platform. To automate the measurement of travel time, the Arduino Uno board was used, and two water sensors were installed at the initial (h0) and final (h1) heights of the water inside the core. When the water flows across the soil and the water level passes the bottom part of the initial sensor (h0), the time recording starts; it ends when the water is absent from the final height of the second sensor (h1). The equation for calculating the hydraulic conductivity was inserted into the algorithm so the calculation was automatic. Undisturbed soil samples were taken in a long-term no-tillage area. There were no significant differences for the time and hydraulic conductivity means between the permeameters. The coefficient of the residual mass index showed an overestimation of the time variable; thus, the automated permeameter improves the precision of time recording and saturated hydraulic conductivity estimated by the falling head method.

Study on the Formation of Reactive Material Shaped Charge Jet by Trans-Scale Discretization Method

The formation process of reactive materials shaped charge is investigated by X-ray photographs and numerical simulation. In order to study the formation process, a trans-scale discretization method is proposed. A two-dimensional finite element model of shaped charge and reactive material liner is established and the jet formation process, granule size difference induced particle dispersion and granule distribution induced jet particle distribution are analyzed based on Autodyn-2D platform and Euler solver. The result shows that, under shock loading of shaped charge, the Al particle content decreases from the end to the tip of the jet, and increases as the particle size decreases. Besides, the quantity of Al particles at the bottom part of the liner has more prominent influence on the jet head density than that in the other parts, and the Al particle content in the high-speed section of jet shows inversely proportional relationship to the ratio of the particle quantity in the top area to that in the bottom area of liner.

Changing parameters of waters chemical composition in the Lake Arakhley water column (Eastern Transbaikalia)

The need to preserve the quality of water resources under conditions of anthropogenic impact is one of the most urgent problems of our time. The purpose of this work was to study the features of the distribution of the parameters of the chemical composition of the waters of Lake Arakhley in a vertical section. The investigated waters are characterised by a constancy of mineralisation and chemical composition, both within the water area and in the vertical section. The waters are ultra-fresh (salinity less than 200 mg / L), neutral and slightly alkaline (average pH 7.9), HCO3 Mg-Ca chemical composition. The carbon dioxide content in the water column has a significant impact on the concentration of hydrogen ions, as evidenced by the inverse relationship between pH and CO2 content. The observed increase in the nitrogen form and CO2 contents in the bottom part of the lake is most likely related to the life processes of organisms and vegetation. The recorded excess concentrations of Mn, Cu, Ni, and Al over maximum permissible concentrations indicate the need for additional studies to identify their sources.

Innovative Technology for Stamping a Small-Sized Sleeve Blank

The work is devoted to the development of an innovative technology of stamping from low-carbon steel for small-size liner blanks. The sequence of punching transitions includes a cold back extrusion operation, two cold drawing operations with thinning, and a cold crimping operation. Simulation with the use of the finite element method established the forces and specific forces during operations, the thermal effect during shaping, the shape and size of semi-finished products with distributions of the intensity of deformations. An elastoplastic metal model was used, which made it possible to reveal the deformation forces, tool extraction from deformed semifinished products and the effort to remove semifinished products from the dies. A hollow semi-finished product is obtained by reverse extrusion. The possibility of carrying out the first drawing operation with thinning through two sequentially located dies with the formation of a hole in the bottom part is shown. After this operation, annealing of the semi-finished product is required to restore plasticity. In the second operation, thinning stretching. The shape and dimensions of the wall of the semi-finished product after the second drawing, the distribution of the intensity of deformations in it are determined from the condition of reaching the final dimensions and mechanical properties of the sleeve blank at the last crimping operation. For this, the deformations obtained as a result of the second drawing are taken into account when modeling the crimp. For each transition of stamping, a construction of stamping equipment has been developed. The proposed technology for stamping a sleeve blank can be implemented on a universal pressing equipment, has a high productivity due to a reduction in the number of transitions and minimizes mechanical processing.

Introducing New 22? PDC Bit for Drilling Complex Shallow Sections in a Giant Field in the Middle East

Drilling a 22″ section across interbedded, high-impact, and abrasive formations has historically been challenging in giant fields in the Middle East. The section typically ranges from 3,000 ft to 4,000 ft long and requires three to four runs to reach the casing point with conventional TCI bits. This paper covers the introduction of a new 22″ PDC bit design run on rotary assembly, which has spectacularly improved the drilling performance over the conventional tricone bits. The introduction of this new 22″ PDC bit design followed a comprehensive engineering approach. Starting with the simulation of rock properties such as compressive strength, abrasiveness, and impact, a fit-for-purpose bit design was manufactured to address the needed cutting structure, number of blades, and depth of cut for the section. The downhole drilling dynamics were also thoroughly analyzed, and the bottom hole assembly configuration was revisited to match up with the new bit structure. Within the dedicated continuous improvement workflow set by the service company, the bit pattern was further optimized after the initial field trials. After an in-depth analysis of the various formation properties and their impact on bit life, the 22″ section was divided into two target runs. The upper part has high-impact and interbedded layers, and the lower part has high abrasiveness and formation compressive strength. In the upper part, the TCI bits had previously shown relatively good performance with acceptable ROP, while the PDC bits experienced damage to their cutting structure. As the impacts were lower in the bottom part, the PDC bit design was selected for the second run to the casing point, which resulted in significantly higher ROP and a longer lifetime than the TCI runs. The 2-bit strategy, spudding the section with the TCI bit and completing it with the PDC bit on rotary assembly, translated into a significant improvement of ROP by 32%. In addition to saving rig time, the overall number of bit runs was reduced by 29%, resulting in cost savings by using fewer bits. Drilling the section in two runs has now become the norm, and this winning strategy was adopted as the new standard for drilling the 22″ hole section. The introduction of the 22″ PDC bit on rotary drive returned excellent results and record-breaking ROP performance. While the 22″ PDC cost might seem prohibitive, the substantial rig time savings proved this solution to be very economical. Further development of this initiative to other basins in the Middle East or elsewhere will mutually benefit both the operator and service company.

Metasurface Superstrate Beam Steering Antenna with AMC for 5G/WiMAX/WLAN Applications

A beam-steering antenna based on non-uniform metasurface superstrate and AMC, operating at 3.5 GHz, is presented. The antenna can steer the beam along θ = -18° and 18° with the superstrate and along θ = 0° in the absence of the superstrate with almost zero scan loss. Antenna structure consists of a top layer of non-uniform metasurface superstrate made of a 20 × 20 grid of electrically-small square-shaped metallic pixels while the bottom part consists of AMC with a grid of 5 × 5 pixels. The radiating element, CPW-fed monopole antenna, is placed between AMC and superstrate. The fabricated prototype shows desired beam steering in directions of θ = -18°, 0°, and 18° while maintaining uniform realized gain of 5.5 dB and matches well with simulations.

Experimental and computational evaluation of a gas-solid suspension density distribution under circulating fluidized bed conditions

The paper presents the results of operational measurements of the suspension density distribution in the 966 MWth supercritical Circulating Fluidized Bed boiler. The tests were carried out for four different unit thermal loads, i.e. 40, 60, 80, and 100% MCR. The conducted operational measurements showed that the suspension density distribution of the particulate material in the combustion chamber of the CFB boiler has the form of an exponential curve with maximum values occurring in the bottom part of the furnace. On the basis of the operational data, an attempt was made to reflect the suspension density distribution in the combustion chamber of the boiler using the ANSYS CFD software. The calculations were carried out using the Eulerian multiphase model in an unsteady state condition. As revealed by the simulations, the Eulerian multiphase model allows for a quantitative representation of the suspension density distribution of the granular material only for the maximum boiler load. For other thermal loads, quantitative representation of experimental distributions of suspension density using the Eulerian method is possible except for the dense region.

Effect of Different Bag Opening Methods of Oyster Mushroom (Pleurotus ostreatus) on Growth Parameter, Yield and Benefit Cost Ratio

Oyster mushroom growers are generally confused about the scientific basis of the cultivation technology with regard to the best bag opening method after a spawn run. The present study was undertaken to find out the effect of four different methods of bag opening on yield, benefit cost ratio (BCR) and biological efficiency of oyster mushrooms during November, 2020 to March, 2021. The results indicated that treatment-2 (retaining the polythene bag for the entire cultivation period) exhibited significantly the highest yield (1644.61 g bed-1) followed by treatment-3 (opening top part of the polythene bag after spawn run) (1536.62 g bed-1), and treatment-1 (opening top and bottom part of the polythene bag (1468.82 g bed-1) and treatment-4 (complete removal of the polythene bag) (1111.19 g). The BCR was also found to be the highest (4.39) in treatment-2 followed by treatment-3 (4.09), treatment-1 (3.96) and treatment-4 (2.98). Retaining the polythene bag during the entire cultivation period was found to be the best method of cultivation with regard to biological efficiency (82.23%). Opening the top part of the polythene bag after the spawn run showed the biological efficiency of 76.83% which was followed by the treatment with opening the polythene bag from the top and bottom part of the bed (73.44%).The lowest biological efficiency (55.56%) was observed in the treatment in which the entire polythene bag was removed after a spawn run in darkroom. Mushroom growers may retain the polythene bag surrounding the mushroom bed during the entire cultivation period for better economic return.

Influence of particles size distribution on the carbon content throughout sinter bed height

By the previous studies it was established that the character of solid fuel distribution throughout the bed height considerably effects the sintering machines productivity and the sinter quality. The purpose of the study was assessment of solid fuel distribution in the agglomerated burden throughout the height of bed at sintering machine. Sinter mix samples were taken from three sections of the bed: 150 mm - top part, 150 mm - middle part and 170 mm - bottom part at the sintering machines of NLMK. After screening the samples, particle size distribution was determined, as well as carbon content throughout the bed height and in the particles of different sizes. It was found that all solid fuel, irrespective of the size, gets balled into sinter mix granules, fine fuel (fraction -0.63 mm) was almost evenly distributed over the granules of different sizes, while coarse fuel (+3 mm) is mainly picked up by large granules. Solid fuel of -3 mm +0.63 mm fraction is mostly balled into 3-5 mm granules. Such nature of solid fuel distribution in the granules of the pelletized mix results in suboptimal distribution of fuel throughout the bed height at sintering machines No. 1, 2, despite satisfactory size segregation of the mix: it changes from low content in the top part to a higher content at the bottom of the bed. At sintering machines No. 3, 4 where there was no size segregation of the mix, fuel distribution throughout the bed height changes from optimal to non-optimal (low content in the top part). To optimize solid fuel distribution throughout the bed height with both good and poor segregation of the mix, it is necessary to reduce the content of 0-0.5 mm particles fraction in coke breeze.

Effects of overstory tree density, site preparation and ground vegetation on natural Scots pine seedling emergence and survival in northern boreal pine forests

Natural regeneration is commonly used forest regeneration method in Northern Finland. It is not known however, what would be the optimal overstory density and ground vegetation composition for seedling emergence and survival, and if site preparation is needed to accompany overstory density manipulation. We studied the effects of overstory density (unthinned control and thinning to 50, 150 and 250 trees ha-1) and ground vegetation removal (mechanical site preparation with disc trenching) on the number of naturally germinated pine seedlings and survival of individual seedlings during 8-11 years. Bare mineral soil was a superior seedbed compared to intact vegetation cover, even though also mortality rate was high on mineral soil. Greater cover of lingonberry, crowberry and slash had a negative effect on seedling number. Seedling mortality was initially high (60% died during the first two years) but decreased throughout the first five years. The mineral soil in the elevated part of disc trencher track showed twice the survival rate in the bottom part of the track. High coverage of small haired mosses was associated with poorer seedling survival. An overstory density of 50-150 trees ha-1 with site preparation seems to be an efficient treatment to promote regeneration under these circumstances.