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Abstract

The study integrates geophysical and geotechnical methods for subsoil evaluation and shallow foundation design. The study involved six vertical electrical sounding and geotechnical investigation involving cone penetration test and laboratory soil analysis. Three major geologic units were delineated; the topsoil, weathered layer and partly weathered/fractured/fresh bedrock. The overburden thickness is in between 15.2–32.9 m. Based on resistivity (16–890 ohm-m) and thickness (12.7–32 m) the weathered layer is competent to distribute structural load to underlying soil/rock. The groundwater level varies from 4.5 to 12.3 m. Therefore an average allowable bearing capacity of 200 kPa is recommended and would be appropriate for design of shallow foundation in the area, at a depth not less than 1.0 m with an expected settlement ranging from 9.03–48.20 mm. The ultimate bearing and allowable bearing capacity for depth levels of 1–3 m vary from 1403–2666 kPa and 468–889 kPa for strip footing while square footing varies in between 1956–3489 kPa and 652–1163 kPa respectively.

Abstract

The article presents an original optical system to measure displacements across joints or cracks in building structures. It describes the concept of system operation, algorithms to be followed and results of practical tests that have been performed.

The proposed solution is based on digital photos taken with a non-metric digital camera, modified by defining its internal orientation elements and correction of lens distortion during calibration, constituting the measurement instrument registering the pictures of markers. QR (Quick Response) codes are proposed to be the markers. Being digitally processed, a set of registered images allow visualising the measured size of occurred displacements.

Owing to this solution, it is possible to obtain data on a mutual position of two or more QR codes in the form of translation elements in 3D space and appropriate three orientation angles. Appointed elements are unequivocal in spatial interpretation and not limited by dimension.

As the tests performed by the authors show, the results are more than satisfactory. The proposed measurement technology is an objective system of data acquisition, suitable for automating the whole monitoring process of displacements of building structure elements concerning joints and cracks.

Abstract

In this article, we have investigated a fitting proposal model for calculating the crystallite size of pure NiO thin films by varying the structural parameters, such as full width at half-maximum β, lattice parameter a and differences in aa 0. The experimental data of NiO thin films were prepared at several deposition temperatures in the range of 380–460°C. All estimated values of crystallite sizes are proportional to the experimental data. Thus, the measurement of the crystallite size values by this proposed model is compatible with practical measurements qualitative.

Abstract

Ureje Dam, Ado-Ekiti has witnessed drastic reduction in the water storage capacity of its reservoir. It became imperative to determine the possible cause(s) of the reduction in storage capacity. Geophysical investigation involving the vertical electrical sounding technique of the electrical resistivity method was conducted in the upstream part of the dam. Five lithologic units that include the mud/suspended materials, such as sandy clay, clay, weathered/fractured bedrock and fresh bedrock, were delineated. The respective resistivity and thickness range of the units are 2–19 ohm-m; 147–206 ohm-m, 2–38 ohm-m; 47–236 ohm-m and 455–1516 ohm-m and 0.4–1.9 m; 0.5–2.5 m; 1.0–12.2 m; 7.3–16.4 m and ∞. The thickness of suspended materials, resistivity/thickness of weathered layer and the presence of near-surface impervious layer were used as the main indices for the spatial demarcation of the dam axis in terms of vulnerability to loss of impounded water. Using the cumulative response of the indices, the study concluded that the eastern to southeastern parts of the dam axis showed the highest indications of vulnerability to loss of impounded water.

Abstract

The article presents the grain size distribution of soil samples from the Precambrian basement within the purview of the textural properties, deduced transportation history and the numerical assessments using statistical parameters. The fourteen soil samples collected from the study area were subjected to sieve analysis in the laboratory for the determination of their grain size distribution. The statistical parameters’ study includes the graphic mean, skewness, sorting and kurtosis. The result of the analysis of the soil samples ranged from coarse to fine-grained samples, moderately and poorly sorted, positively and negatively skewed and the kurtosis also shows leptokurtic as the most dominant which suggests the samples poorly distributed and moderately sorted at the centre of the grain size distribution. These results also suggest the geological environment of the soil samples could be responsible for the poorly and moderately sorted exhibited by the samples deposited in the location.

Abstract

Lithium additions to Al offer the promise of substantially reducing the weight of alloys, since each 1 wt. % Li added to Al reduces density by 3 % and increases elastic modulus. In the present work, the effect of 1.46 wt. % Li addition to AlSi7Mg (containing 7.05 wt. % Si and 0.35 wt. % Mg) was studied. The alloy showed reduced density and higher hardness after natural ageing. Experimental work showed that micro-structural and mechanical properties changed with Li addition. It was observed that 0.80 wt. % Li addition resulted in formation of new phase AlLiSi which has a great effect to increase hardness of AlSi7Mg. According to Scanning Electron Microscope (SEM) and X-ray diffraction analysis it was confirmed that the addition of Li causes formation of different phases which are: α-Al, β-Si and AlLiSi.

Abstract

In this paper, research on the possibilities of sodium sulphate (Na2SO4) separation from other substances in the filter ash sample is presented. The research material contains six components that differ in chemical composition and density. The possibilities of Na2SO4 separation using dry and wet methods were studied. The dry method was based on separation with a centrifugal air classifier at four cut size limits. The wet method was based on the dissolution of water-soluble components, filtration of insoluble components, and drying the products. The sulphur content of the individual products was determined using both methods. The aim of the research was to determine which method is more suitable for separation of the material in a way that most of the material would contain as little sulphur as possible and the rest of the material would contain concentrated sulphur. The wet method proved to be more successful. The product with mass fraction 33.1% of the total mass, obtained from the aqueous solution, contained 8.39% sulphur after filtration and drying. The water-insoluble component, with mass fraction 66.9% of the total mass, contained 0.56% sulphur. The dry method with the centrifugal air classifier proved to be less successful in comparison with the wet method. The particles containing Na2SO4 are very similar in size and density to the other components of the material, so the separation to the desired extent was not achieved.

Abstract

The paper presents the analysis of accessibility and usability of Landsat 8 Satellite Imagery for the purpose of Satellite Derived Bathymetry (SGB) products generation of the area of near-shore waters of the Polish coast. General assumptions of the SDB, Landsat program and factors affecting the products generation process have been described in details. Examples of SDB results, generated using both GIS software and Matlab, are presented on the example of chosen areas of Gulf of Gdańsk. The advantages and disadvantages of the SDB method are presented in the discussion and conclusion part with the proposed directions for the future works.

Abstract

The paper presents a concept of overall BLDC drive model. Target model will be improved with a functional model of battery cell, which is commonly used as a power supply for the drive. The paper shows previous achievements in form of a functional BLDC motor model. Also, simulation results are presented. These are the partial results, that aimed to verify the basic model’s correctness as a basis of future developments. The procedure of power source selection presented in the article is vital to specify the technical parameters of modelled battery cell.

Abstract

Detection of small objects in the airspace is a crucial task in the military. In the era of today’s unmanned aerial vehicles (UAVs) technology, many military units are exposed to recognition and observation through flying objects. They are often equipped with optoelectronic warhead making a way to collect essential and secret data of the military unit. Modern technical solutions make it possible to implement some methods facilitating detection of flying objects. A lot of them utilize computer vision techniques based on image processing algorithm. Therefore, in this article, we present an analysis of the most promising algorithm for detection of small flying objects.