The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Estrella Cadahia - One of the best experts on this subject based on the ideXlab platform.
-
micro oxygenation strategy depends on origin and size of oak chips or staves during accelerated red wine aging
Analytica Chimica Acta, 2010Co-Authors: Maria Del Alamo, Ignacio Nevares, Laura Gallego, Brigida Fernandez De Simon, Estrella CadahiaAbstract:Abstract The practice of wine aging in stainless Steel Tank involves storing wine in contact with wood and dosing it with small oxygen quantities in order to obtain a final wine more stable in time and with the same characteristics of barrel-aged wines. Oxygen dosing is a key factor and, to achieve a correct development of wine, needs to be applied according to wine necessities and to the kind of wood chosen. This paper shows the results obtained from the study of oxygen required by a same wine aged in Tanks with different alternative products (chips and staves) made of American (Q. alba ), French (Q. petraea ) and Spanish oak (Q. pyrenaica ), with a strategy of micro-oxygenation as required. The results indicate that the size and origin of the wood used determine the oxygen management during the process. In fact, wine treated with big pieces (staves) consumes more oxygen and, with regard to wood origin, wine aged with French oak (Q. petraea ) products needs of a higher oxygen dosage.
Robert Jankowski - One of the best experts on this subject based on the ideXlab platform.
-
Experimental determination of dynamic properties of cylindrical Steel Tank model filled with liquid
2020Co-Authors: Daniel Burkacki, Robert Jankowski, Tomasz FalborskiAbstract:In technical branches, such as chemical or petroleum industries, cylindrical Steel Tanks are essential structures used for storage of liquid products. Any failure might have disastrous consequences, therefore their safety and reliability is essential. The aim of the present paper is to show the results of the experimental study which has been conducted on a scaled model of a real Tank used in Poland. The investigation was carried out using the shaking table. The study included impact tests with modal analysis and harmonic tests of dynamic properties. The influence of liquid level on the natural vibration modes and natural frequencies has been investigated. The results of the study indicate that stored product may significantly influence the values of dynamic parameters.
-
Experimental study on models of cylindrical Steel Tanks under mining tremors and moderate earthquakes
Earthquakes and Structures, 2019Co-Authors: Daniel Burkacki, Robert JankowskiAbstract:The aim of the study is to show the results of complex shaking table experimental investigation focused on the response of two models of cylindrical Steel Tanks under mining tremors and moderate earthquakes, including the aspects of diagnosis of structural damage. Firstly, the impact and the sweep-sine tests have been carried out, so as to determine the dynamic properties of models filled with different levels of liquid. Then, the models have been subjected to seismic and paraseismic excitations. Finally, one fully filled structure has been tested after introducing two different types of damages, so as to verify the method of damage diagnosis. The results of the impact and the sweep-sine tests show that filling the models with liquid leads to substantial reduction in natural frequencies, due to gradually increasing overall mass. Moreover, the results of sweep-sine tests clearly indicate that the increase in the liquid level results in significant increase in the damping structural ratio, which is the effect of damping properties of liquid due to its sloshing. The results of seismic and paraseismic tests indicate that filling the Tank with liquid leads initially to considerable reduction in values of acceleration (damping effect of liquid sloshing); however, beyond a certain level of water filling, this regularity is inverted and acceleration values increase (effect of increasing total mass of the structure). Moreover, comparison of the responses under mining tremors and moderate earthquakes indicate that the power amplification factor of the mining tremors may be larger than the seismic power amplification factor. Finally, the results of damage diagnosis of fully filled Steel Tank model indicate that the forms of the Fourier spectra, together with the frequency and power spectral density values, can be directly related to the specific type of structural damage. They show a decrease in the natural frequencies for the model with unscrewed support bolts (global type of damage), while cutting the welds (local type of damage) has resulted in significant increase in values of the power spectral density for higher vibration modes.
-
Diagnosis of Damage in a Steel Tank with Self-Supported Roof through Numerical Analysis
Key Engineering Materials, 2013Co-Authors: Daniel Burkacki, Michał Wójcik, Robert JankowskiAbstract:The safety of civil engineering structures is one of the most important issues of building industry. That is why the assessment of the damage-involved structural response has recently become of major concern to engineers. Among a number of different approaches to diagnosis of damage, the method of measuring the changes in natural frequencies is considered to be one of the most effective indicators of global damage. From the practical point of view, the method has been successfully applied to relatively small structures, while in-situ tests on large structures, such as bridges, Tanks or dams, are very difficult. The aim of the present paper is to show the results of the numerical analysis concerning the diagnosis of damage in a cylindrical Steel Tank with self-supported roof which is filled with liquid. The tests have been conducted for various stages of damage, introduced in the numerical model by reducing the stiffness of Tank-soil system as well as by cutting the connection between the shell and roof of the Tank as well as between roof elements. The results of the numerical analysis have shown the characteristic decrease in the natural frequencies for the case of Tank-soil system with reduced stiffness, which is the global type of damage. On the other hand, cutting the welds, which can be considered as the local type of damage, has not lead to the differences in the natural frequency values, although differences in local deformations of shell in the vicinity of cuts have been observed in vibration modes.
-
Diagnosis of Damage in a Steel Tank Model by Shaking Table Harmonic Tests
Key Engineering Materials, 2012Co-Authors: Daniel Burkacki, Robert JankowskiAbstract:Diagnosis of damage in civil engineering structures has recently become an important issue in the safety assessment procedure. Among a number of different approaches, a method of measuring the changes in natural frequencies is one of the most effective indicators of global damage. It has been successfully applied to relatively small structures, however, the tests on large structures are very difficult and the practical application of the method still requires further investigations. The aim of the present paper is to show the results of the shaking table experimental study concerning the diagnosis of damage in a model of cylindrical Steel Tank with self-supported roof which is filled with liquid. During the tests, the base of the structure was excited under the harmonic loading with variable frequency. The tests were repeated for different stages of damage, which was introduced in the model by easing the bolts of structural supports as well as by cutting the welds between the shell and roof as well as between roof elements. The results of the study show a characteristic decrease in the natural frequencies for the case of structural supports with reduced stiffness (global type of damage). On the other hand, cutting the welds (local type of damage) has lead to the considerable increase in the power spectral density values for higher vibration modes.
M.c. Duffy - One of the best experts on this subject based on the ideXlab platform.
-
The mercury-arc rectifier and supply to electric railways
Engineering Science and Education Journal, 1995Co-Authors: M.c. DuffyAbstract:The introduction in the 1890s of the heavy-duty LVDC rapid-transit railway, drawing current from an AC power station, required some form of rectifier for converting the supply to DC in the conductor rail or contact wire. The development of the HVDC railway by 1915 likewise necessitated rectifiers. Though the principle of using the mercury arc to convert AC to DC was well understood by 1905, the first valves, owing much to Cooper-Hewitt, were too low in capacity to serve railway needs before the early 1920s, and railway electrification relied on rotary converter sets. By the 1920s, both the glass-bulb and Steel-Tank types of mercury-vapour rectifier were sufficiently developed to be used in railway service, first for battery charging, then as supplements to rotary sets, and finally as main power rectifiers. Throughout the 1930s, both the glass-bulb type, and the multianode Steel-Tank rectifier were installed in automatic substations, remotely controlled. In Great Britain, London Transport pioneered their extensive use. Between 1945 and 1965, the air-cooled, pumpless rectifier found favour, but the developments in solid-state semiconductor rectifiers led to their replacement throughout industry. The types of mercury-arc rectifier mounted on locomotives proved unreliable in this service, and hence relatively few were used in this capacity. In stationary use, all major types of mercury-arc rectifier performed well, and in railway service the majority were employed in lineside substations.
Daniel Burkacki - One of the best experts on this subject based on the ideXlab platform.
-
Experimental determination of dynamic properties of cylindrical Steel Tank model filled with liquid
2020Co-Authors: Daniel Burkacki, Robert Jankowski, Tomasz FalborskiAbstract:In technical branches, such as chemical or petroleum industries, cylindrical Steel Tanks are essential structures used for storage of liquid products. Any failure might have disastrous consequences, therefore their safety and reliability is essential. The aim of the present paper is to show the results of the experimental study which has been conducted on a scaled model of a real Tank used in Poland. The investigation was carried out using the shaking table. The study included impact tests with modal analysis and harmonic tests of dynamic properties. The influence of liquid level on the natural vibration modes and natural frequencies has been investigated. The results of the study indicate that stored product may significantly influence the values of dynamic parameters.
-
Experimental study on models of cylindrical Steel Tanks under mining tremors and moderate earthquakes
Earthquakes and Structures, 2019Co-Authors: Daniel Burkacki, Robert JankowskiAbstract:The aim of the study is to show the results of complex shaking table experimental investigation focused on the response of two models of cylindrical Steel Tanks under mining tremors and moderate earthquakes, including the aspects of diagnosis of structural damage. Firstly, the impact and the sweep-sine tests have been carried out, so as to determine the dynamic properties of models filled with different levels of liquid. Then, the models have been subjected to seismic and paraseismic excitations. Finally, one fully filled structure has been tested after introducing two different types of damages, so as to verify the method of damage diagnosis. The results of the impact and the sweep-sine tests show that filling the models with liquid leads to substantial reduction in natural frequencies, due to gradually increasing overall mass. Moreover, the results of sweep-sine tests clearly indicate that the increase in the liquid level results in significant increase in the damping structural ratio, which is the effect of damping properties of liquid due to its sloshing. The results of seismic and paraseismic tests indicate that filling the Tank with liquid leads initially to considerable reduction in values of acceleration (damping effect of liquid sloshing); however, beyond a certain level of water filling, this regularity is inverted and acceleration values increase (effect of increasing total mass of the structure). Moreover, comparison of the responses under mining tremors and moderate earthquakes indicate that the power amplification factor of the mining tremors may be larger than the seismic power amplification factor. Finally, the results of damage diagnosis of fully filled Steel Tank model indicate that the forms of the Fourier spectra, together with the frequency and power spectral density values, can be directly related to the specific type of structural damage. They show a decrease in the natural frequencies for the model with unscrewed support bolts (global type of damage), while cutting the welds (local type of damage) has resulted in significant increase in values of the power spectral density for higher vibration modes.
-
Diagnosis of Damage in a Steel Tank with Self-Supported Roof through Numerical Analysis
Key Engineering Materials, 2013Co-Authors: Daniel Burkacki, Michał Wójcik, Robert JankowskiAbstract:The safety of civil engineering structures is one of the most important issues of building industry. That is why the assessment of the damage-involved structural response has recently become of major concern to engineers. Among a number of different approaches to diagnosis of damage, the method of measuring the changes in natural frequencies is considered to be one of the most effective indicators of global damage. From the practical point of view, the method has been successfully applied to relatively small structures, while in-situ tests on large structures, such as bridges, Tanks or dams, are very difficult. The aim of the present paper is to show the results of the numerical analysis concerning the diagnosis of damage in a cylindrical Steel Tank with self-supported roof which is filled with liquid. The tests have been conducted for various stages of damage, introduced in the numerical model by reducing the stiffness of Tank-soil system as well as by cutting the connection between the shell and roof of the Tank as well as between roof elements. The results of the numerical analysis have shown the characteristic decrease in the natural frequencies for the case of Tank-soil system with reduced stiffness, which is the global type of damage. On the other hand, cutting the welds, which can be considered as the local type of damage, has not lead to the differences in the natural frequency values, although differences in local deformations of shell in the vicinity of cuts have been observed in vibration modes.
-
Diagnosis of Damage in a Steel Tank Model by Shaking Table Harmonic Tests
Key Engineering Materials, 2012Co-Authors: Daniel Burkacki, Robert JankowskiAbstract:Diagnosis of damage in civil engineering structures has recently become an important issue in the safety assessment procedure. Among a number of different approaches, a method of measuring the changes in natural frequencies is one of the most effective indicators of global damage. It has been successfully applied to relatively small structures, however, the tests on large structures are very difficult and the practical application of the method still requires further investigations. The aim of the present paper is to show the results of the shaking table experimental study concerning the diagnosis of damage in a model of cylindrical Steel Tank with self-supported roof which is filled with liquid. During the tests, the base of the structure was excited under the harmonic loading with variable frequency. The tests were repeated for different stages of damage, which was introduced in the model by easing the bolts of structural supports as well as by cutting the welds between the shell and roof as well as between roof elements. The results of the study show a characteristic decrease in the natural frequencies for the case of structural supports with reduced stiffness (global type of damage). On the other hand, cutting the welds (local type of damage) has lead to the considerable increase in the power spectral density values for higher vibration modes.
Maria Del Alamo - One of the best experts on this subject based on the ideXlab platform.
-
micro oxygenation strategy depends on origin and size of oak chips or staves during accelerated red wine aging
Analytica Chimica Acta, 2010Co-Authors: Maria Del Alamo, Ignacio Nevares, Laura Gallego, Brigida Fernandez De Simon, Estrella CadahiaAbstract:Abstract The practice of wine aging in stainless Steel Tank involves storing wine in contact with wood and dosing it with small oxygen quantities in order to obtain a final wine more stable in time and with the same characteristics of barrel-aged wines. Oxygen dosing is a key factor and, to achieve a correct development of wine, needs to be applied according to wine necessities and to the kind of wood chosen. This paper shows the results obtained from the study of oxygen required by a same wine aged in Tanks with different alternative products (chips and staves) made of American (Q. alba ), French (Q. petraea ) and Spanish oak (Q. pyrenaica ), with a strategy of micro-oxygenation as required. The results indicate that the size and origin of the wood used determine the oxygen management during the process. In fact, wine treated with big pieces (staves) consumes more oxygen and, with regard to wood origin, wine aged with French oak (Q. petraea ) products needs of a higher oxygen dosage.
