Results of comparing astronomical-geodetic and navigational-geodetic methods of determining the components of the deflection of vertical

The authors present the results of comparing the components of deflection of vertical obtained through astronomical-geodetic and navigational-geodetic methods. The first one is based on comparing astronomical and geodetic coordinates of a location. This method has recently been widely implemented in a digital zenith camera systems using a small-sized digital telescope with an astronomical camera based on CCD or CMOS technologies, a high-precision inclinometer and satellite navigation system receiver. In this case, the combination of a telescope, an astronomical camera and an inclinometer enables determining the local direction of the plumb line, expressed by astronomical coordinates, from observations of stars at the zenith and using high-precision star catalogs. The navigational-geodetic method is based on comparing the results of the normal heights’ increments, defined through geometric leveling, and geodetic heights, computed with the relative method of satellite coordinate determinations. For each method, random and systematic components of the error and its confidence bounds were calculated; the absolute values of the deflection of vertical components at two geographically separated points were compared.

Ecological and Energy Efficiency of Wood Pellets’ Production

In the technological cycle of enterprises of the forestry complex, a significant amount of wood waste is generated, but due to their high humidity, low energy density and heterogeneous granulometric composition, they refer to difficulty combustible fuels. The perspective direction of their enrichment is granulation. The results of comprehensive study of the energy and environmental performance of industrial lines of granulation of byproducts of sow mill production are presented. The change in thermomechanical characteristics and the fractional composition of wood material in the process of granulation investigated. The components of the heat balance and emissions of gas release are determined. To determine the heat loss to the environment, an elaborated technology based on the application of a relative method supplemented with a television survey. Recommendations for improving the energy-ecological performance of granulation lines are presented.

Evaluation of recent combined global geopotential models in Brazil

The aim of this paper is to present a quantitative analysis of the adequacy of the main currently existing combined Global Geopotential Models (GGMs) for modeling normal-geoid heights throughout Brazil. As major advances have been reached since mid-2016 in the combined GGMs elaboration and development, the main objective of this analysis is to verify if, in fact, the most recent models present superior or equivalent performance to the most performant previous models. The analysis was based on comparisons between normal-geoid height values obtained fromGNSS/leveling solutions and values calculated from GGMs XGM2016, GOCO05C, EIGEN-6C4 and EGM2008, according to different geopotential functionals - geoid height and height anomaly - and in different degrees of development, always through the relative method. This procedure was applied to 997 stations which carry information of both ellipsoidal and normal-orthometric heights, located all over Brazil. As a main result, it was observed the superior performance of the recent combined GGMs, GOCO05C and XGM2016, when compared to the older models, EIGEN-6C4 and EGM2008, when all of them are developed up to degree 720, the maximum degree of the recent models; and a approximate equality of results when all of the models are used in their individual maximum degrees.

Measurement of the High Temperature Elastic Modulus of Alumina Ceramics by Different Testing Methods

Alumina ceramics are widely used in the demanding high temperature applications in which the high temperature elastic moduli (EHT) is a key property for their reliability and safety. In this paper, the elastic modulus of alumina was determined by dynamic method (impulse excitation technique) and static tests (three-point bending test and four-point bending test). For the static tests, the relative method was applied to determine the accurate deflection measurement in the heating furnace. The measured results revealed that the modulus of alumina slowly decreased from RT to 1000 °C and rapidly decreased with the increasing temperatures from 1000 °C to 1300°C. The EHT evaluated by dynamic method were higher than that tested by static tests with the reason of that impulse excitation technique only applied small forces onto a sample such that defects activity is negligible. Also the resonant frequencies couldn’t be measured easily at high temperature, because the vibration signal emitted by the sample was weak. The static approaches combined with relative method were beyond the limit to high temperatures, and they can be also used to evaluate the ultra-high temperature modulus.

Evaluating Corrosion Damage Evolution of Cement Mortar in Acid Environment via Relative Elasticity Modulus Method

In order to study the damage variation along thickness from surface, a relative method combined with impulse excitation test was studied in this work to evaluate the elastic modulus of cement mortar corrosion damage layer, by simulating the damage layer as a coating. The damage layer with different damage degree is treated as multilayer coatings in which each layer has different properties. The elastic modulus of each layer is determined by using the relative method step by step. Single face of Portland cement mortar specimens was exposed in an aggressive environment, with 0%, 5%, 7.5% and 10% HCl content, respectively. The corrosion damage degree and evolution law of the mortar were investigated by measuring the elastic modulus of surface damage layer. With the increase of HCl concentration, thickness of corrosion damage layer increased and the modulus of the damage layer decreased greatly. The elastic modulus of each corrosion layer was obtained at different depths. By this way, damage depth and damage evolution were evaluated effectively.

The model is integrated satellite gyroscopic system operational determination of high-precision bearing

The article considers the possibility of rapid determination of azimuth directions with high accuracy. It is shown that the gyroscopic method and the relative method of space geodesy with high efficiency, allows to obtain the azimuths of the directions with high precision and Autonomous. To achieve high accuracy of orientation with the use of satellite geodetic equipment are encouraged to design observations with regard to the length and azimuth direction, and time of observation. This will allow to abandon the use of the original geodetic framework that will increase efficiency. To improve the reliability of the obtained azimuth directions, it is proposed to integrate the gyroscopic observations and satellite observations without using the original geodesic Foundation. Considered by the joint processing of satellite and gyro measurements as a dual and unequal dimensions. In conclusion, the a priori calculation of observing time and accuracy of the resulting values of azimuth directions.