scholarly journals Degradation of Polymetallic Nodules in Deep-Sea Multi-Stage Lifting Motor Pump

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 656
Author(s):  
Yan Li ◽  
Kesen Liang ◽  
Huan Dai ◽  
Chi Zhang
Keyword(s):  
Particle Size ◽  
Calculation Method ◽  
Deep Sea ◽  
Experimental System ◽  
Design Parameters ◽  
Impeller Blade ◽  
Final Particle ◽  
Processing Equipment ◽  
Multi Stage ◽  
Polymetallic Nodules

The polymetallic nodules in the deep-sea multi-stage lifting motor pump will undergo repeated impeller blade impact and fragmentation, which will change the particle size, thereby affecting the number of ores that can be recovered on the surface and the design parameters of the processing equipment. A new calculation method of degradation rate is proposed. The degradation model of multiple impacts of particles is improved to quantitatively calculate the final particle size distribution (PSD) of polymetallic nodules transported from the Clarion Clipperton Zone (CCZ) to the ground through a series of multi-stage lifting electric pumps. The newly proposed calculation method is obtained by analyzing the degradation of experimental data of polymetallic nodules when they pass through the six-stage lifting motor pump experimental system many times. The improved model is used to predict the PSD of the nodules after running for 10 min in the experimental system, and compared with the experimental test results, the deviation is small. The new method can estimate the change in PSD of nodules due to degradation during transportation, reducing design costs for land processing equipment.

EXPERIMENTAL STUDIES OF REINFORCED CONCRETE STRUCTURES WITH CROSS-SHAPED SPATIAL CRACK UNDER TORSION WITH BENDING

2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Determination ◽  
Calculation Method ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Experimental Scheme

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.

Conjugate Heat Transfer and Film Cooling of a Multi-Stage Cooling Scheme

2008 ◽  
Author(s):  
M. Ghorab ◽  
S. I. Kim ◽  
I. Hassan
Keyword(s):  
Heat Transfer ◽  
Film Cooling ◽  
Gas Turbines ◽  
Conjugate Heat Transfer ◽  
Density Ratio ◽  
Design Parameters ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Multi Stage ◽  
Internal Gap

Cooling techniques play a key role in improving efficiency and power output of modern gas turbines. The conjugate technique of film and impingement cooling schemes is considered in this study. The Multi-Stage Cooling Scheme (MSCS) involves coolant passing from inside to outside turbine blade through two stages. The first stage; the coolant passes through first hole to internal gap where the impinging jet cools the external layer of the blade. Finally, the coolant passes through the internal gap to the second hole which has specific designed geometry for external film cooling. The effect of design parameters, such as, offset distance between two-stage holes, gap height, and inclination angle of the first hole, on upstream conjugate heat transfer rate and downstream film cooling effectiveness performance are investigated computationally. An Inconel 617 alloy with variable properties is selected for the solid material. The conjugate heat transfer and film cooling characteristics of MSCS are analyzed across blowing ratios of Br = 1 and 2 for density ratio, 2. This study presents upstream wall temperature distributions due to conjugate heat transfer for different gap design parameters. The maximum film cooling effectiveness with upstream conjugate heat transfer is less than adiabatic film cooling effectiveness by 24–34%. However, the full coverage of cooling effectiveness in spanwise direction can be obtained using internal cooling with conjugate heat transfer, whereas adiabatic film cooling effectiveness has narrow distribution.

scholarly journals Calculation Method of Permanent Deformation of Asphalt Mixture Based on Interval Number

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2116
Author(s):  
Yue Xiao ◽  
Limin Tang ◽  
Jiawei Xie
Keyword(s):  
Interval Analysis ◽  
Calculation Method ◽  
Design Theory ◽  
Permanent Deformation ◽  
Asphalt Mixture ◽  
Design Parameters ◽  
Interval Variable ◽  
Road Design ◽  
Weight Assignment ◽  
Variable Weight

There are great uncertainties in road design parameters, and the traditional point numerical calculation results cannot reflect the complexity of the actual project well. Additionally, the calculation method of road design theory based on interval analysis is more difficult in the use of uncertain design parameters. In order to simplify the calculation process of the interval parameters in the road design theory, the asphalt pavement design is taken as the analysis object, and the permanent deformation of the asphalt mixture is simplified by combining the interval analysis theory. Considering the uncertainty of the design parameters, the data with boundaries but uncertain size are expressed in intervals, and then the interval calculation formula for the permanent deformation of the asphalt mixture is derived, and the interval results are obtained. In order to avoid the dependence of interval calculation on the computer code, according to the interval calculation rule, the interval calculation method with the upper and lower end point values as point operations is proposed. In order to overcome the contradiction between interval expansion results and engineering applications, by splitting the multi-interval variable formulas, the interval variable weights are reasonably given, and the synthesis of each single interval result realizes a simplified calculation based on interval variable weight assignment. The analysis results show that the interval calculation method based on the point operation rule is accurate and reliable, and the simplified method based on the interval variable weight assignment is effective and feasible. The simplified interval calculation method proposed in this paper provides a reference for the interval application of road design theory.

scholarly journals A thermodynamic assessment of precipitation, growth, and control of MnS inclusion in U75V heavy rail steel

2021 ◽  
Vol 40 (1) ◽  
pp. 178-192
Author(s):  
Wen-Qiang Ren ◽  
Lu Wang ◽  
Zheng-Liang Xue ◽  
Cheng-Zhi Li ◽  
Hang-Yu Zhu ◽  
...  
Keyword(s):  
Particle Size ◽  
Rail Steel ◽  
Solidification Process ◽  
Segregation Ratio ◽  
Two Phase ◽  
Final Particle ◽  
Solid Liquid ◽  
And Control ◽  
Heavy Rail ◽  
Heavy Rail Steel

Abstract Thermodynamic analysis of the precipitation behavior, growth kinetic, and control mechanism of MnS inclusion in U75V heavy rail steel was conducted in this study. The results showed that solute element S had a much higher segregation ratio than that of Mn, and MnS would only precipitate in the solid–liquid (two-phase) regions at the late stage during the solidification process at the solid fraction of 0.9518. Increasing the cooling rate had no obvious influence on the precipitation time of MnS inclusion; however, its particle size would be decreased greatly. The results also suggested that increasing the concentration of Mn would lead to an earlier precipitation time of MnS, while it had little effect on the final particle size; as to S, it was found that increasing its concentration could not only make the precipitation time earlier but also make the particle size larger. Adding a certain amount of Ti additive could improve the mechanical properties of U75V heavy rail steel due to the formation of TiO x –MnS or MnS–TiS complex inclusions. The precipitation sequences of Ti3O5 → Ti2O3 → TiO2 → TiO → MnS → TiS for Ti treatment were determined based on the thermodynamic calculation.

scholarly journals Grinding Kinetics of Slag and Effect of Final Particle Size on the Compressive Strength of Alkali Activated Materials

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 714 ◽  
Author(s):  
Evangelos Petrakis ◽  
Vasiliki Karmali ◽  
Georgios Bartzas ◽  
Konstantinos Komnitsas
Keyword(s):  
Particle Size ◽  
Compressive Strength ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Ageing Time ◽  
Reduction Rate ◽  
Curing Temperature ◽  
Alkali Activation ◽  
Final Particle ◽  
Alkali Activated

This study aims to model grinding of a Polish ferronickel slag and evaluate the particle size distributions (PSDs) of the products obtained after different grinding times. Then, selected products were alkali activated in order to investigate the effect of particle size on the compressive strength of the produced alkali activated materials (AAMs). Other parameters affecting alkali activation, i.e., temperature, curing, and ageing time were also examined. Among the different mathematical models used to simulate the particle size distribution, Rosin–Rammler (RR) was found to be the most suitable. When piecewise regression analysis was applied to experimental data it was found that the particle size distribution of the slag products exhibits multifractal character. In addition, grinding of slag exhibits non-first-order behavior and the reduction rate of each size is time dependent. The grinding rate and consequently the grinding efficiency increases when the particle size increases, but drops sharply near zero after prolonged grinding periods. Regarding alkali activation, it is deduced that among the parameters studied, particle size (and the respective specific surface area) of the raw slag product and curing temperature have the most noticeable impact on the compressive strength of the produced AAMs.

Polymetallic Nodules: Resource Potential and Mining Prospects

2021 ◽  
Vol 55 (6) ◽  
pp. 22-30
Author(s):  
Rahul Sharma
Keyword(s):  
Deep Sea ◽  
Environmental Issues ◽  
Industrial Applications ◽  
Green Energy ◽  
Steady Increase ◽  
Critical Metals ◽  
Alternative Source ◽  
Resource Potential ◽  
Polymetallic Nodules ◽  
International Seabed Authority

Abstract Deep-sea minerals such as polymetallic nodules have attracted significant interest among stakeholders not only for evaluating their potential as an alternative source of critical metals that are required for various industrial applications including green energy but also in developing technology for their exploitation. There has been a steady increase in the number of contractors having exploration rights over large tracts on the seafloor in the “Area,” and the International Seabed Authority that is mandated with the responsibility of regulating such activities is in the process of preparing a code for exploitation of these deep-sea minerals. This commentary takes a look at the resource potential and mining prospects of polymetallic nodules while addressing the economic and environmental issues associated with them.

Combined destruction of ethylene glycol, formaldehyde and methanol by biological methods

2021 ◽  
pp. 40-47
Author(s):  
М.Г. Зубов ◽  
Е.В. Вильсон ◽  
В.А. Литвиненко ◽  
А.А. Кадревич
Keyword(s):  
Ethylene Glycol ◽  
Pilot Plant ◽  
Treatment Plant ◽  
Ammonium Nitrogen ◽  
Design Parameters ◽  
Specific Rate ◽  
Toxic Substances ◽  
Multi Stage ◽  
Enhanced Biodegradation ◽  
Biological Methods

Целью прикладного научного исследования является определение удельной скорости окисления токсичных органических соединений – этиленгликоля, формальдегида и метанола – сообществом микроорганизмов иммобилизованного биоценоза на носителе ЁРШ®, установленном в пилотной установке. Для достижения поставленной цели реализован многоэтапный эксперимент, позволивший определить возможность глубокой биодеградации токсичных веществ и установить необходимую концентрацию азота аммонийного в исходной сточной воде для реализации процесса биодеградации. В ходе исследования были выполнены следующие работы: определение времени выхода на режим пилотной установки после плановой остановки в подаче сточных вод на 31-й день; оценка удельной скорости окисления прикрепленным биоценозом по показателям этиленгликоль, формальдегид, ХПК, БПК; оценка ассимиляции и трансформации соединений азота; формулирование выводов на основе проведенного анализа результатов исследований, необходимых для оценки целесообразности применения биологической очистки сточных вод прикрепленным биоценозом исследуемых загрязнителей и определения расчетных параметров очистного сооружения. The objective of the applied scientific research is to determine the specific rate of oxidation of toxic organic compounds – ethylene glycol, formaldehyde and methanol – by the community of microorganisms of the immobilized biocenosis on the IORSh carrier installed in a pilot plant. To achieve this goal, a multi-stage experiment was carried out that provided for determining possible enhanced biodegradation of toxic substances and specifying the required concentration of ammonium nitrogen in raw wastewater for the implementation of the biodegradation process. In the course of the study, the following works were carried out: determining the process stabilization time in the pilot plant after the scheduled shutdown in the wastewater supply on the 31stday; assessing the specific rate of oxidation by the attached biocenosis in terms of ethylene glycol, formaldehyde, COD, BOD; assessing the assimilation and transformation of nitrogen compounds; drawing conclusions based on the analysis of the research results required for estimating the feasibility of using biological wastewater treatment with the attached biocenosis of the pollutants under study and determining the design parameters of the treatment plant.

scholarly journals Silurian metalliferous nodules from the region of Asaritsa peak, West Balkan mountain – preliminary results

2020 ◽  
Vol 81 (3) ◽  
pp. 75-77
Author(s):  
Atanas Hikov ◽  
Valeri Sachanski ◽  
Zlatka Milakovska ◽  
Elitsa Stefanova ◽  
Irena Peytcheva ◽  
...  
Keyword(s):  
Deep Sea ◽  
Nodule Formation ◽  
Deposition Mechanism ◽  
Preliminary Results ◽  
Polymetallic Nodule ◽  
Polymetallic Nodules

First data for polymetallic nodules and host sediments in Silurian sequence from the region of Asaritsa peak, West Balkan mountain are presented. The nodules are rich of Fe, Mn, Co and Ni. Both sediments and nodules have high content of REE. The described Silurian nodules and sediments show a number of similarities with modern deep-sea polymetallic nodule bearing sediments. Some differences such as probable depth of deposition, mechanism of nodule formation, degree of lithification are also established.

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