Engineering Calculations Research Articles

The HVAC system engineering method for a new family of unified cabins of combine harvesters

BACKGROUND: Designing a combine harvester cabin climate system is a complex and multi-stage process that includes solving a set of tasks. To solve them, a design engineer must have knowledge and skills in various fields, starting with thermal engineering calculations and ending with experimental research methods and computer modeling, which requires a large amount of intellectual and time resources. Therefore, the task of creating a unified method of engineering of combine harvester cabin HVAC system is highly relevant. AIM: Development of the HVAC system for a unified cabin of a grain harvester and a forage harvester. The designed HVAC system is purposed to create a comfortable microclimate in the cabin of the combine for 2 people in summer and winter operating conditions. METHODS: The methodology of calculation and selection of the combine harvester cabin HVAC system, which includes the development of engineering calculation methods and mathematical modeling of thermodynamic and ventilation processes in the cabin, is considered. RESULTS: The main parameters were determined: heat intakes and heat losses for the grain harvester and forage harvester cabins, which amounted to 2.8 and 2.2 kW for the grain harvester, 2.9 and 2.35 kW for the forage harvester; the required air flow rate supplied to the cabin to ensure a comfortable temperature — 740 m3/h; the percentage of air recirculation regarding the conditions of absence of fogging and creation of excessive pressure in the cabin — 75%; the cooling and heating capacity of the HVAC system, taking into account the operating conditions of the combine, are 7.8 and 6.3 kW respectively. The selection of the main equipment of the HVAC system for a unified cabin for a new family of unified cabins of combines — the BUHLER 1000 MFWD evaporator-heater and the Valeo TM16 compressor are chosen. CONCLUSION: The HVAC system designed in accordance with the presented methodology is capable of ensuring a comfortable cabin air temperature in the range of 22–24 °C at various operating modes of the combine harvester in different regions. In addition, the HVAC system parameters eliminate fogging of the cabin windows and the penetration of dusty air inside due to the created excessive pressure.

A novel approach based on a mathematical algorithm and measurement of involute flanks for computing spur gear dimensions with unknown parameters

AbstractInvolute gears of all sizes and types are widely utilized in most machinery. Accurate generation of teeth flanks from the nominally required base circle is most vital in gear manufacturing, performance, and inspection. Despite the vital importance of the base circle in actual gear performance, it is not a widely used inspection parameter. Moreover, the size of base circle radius and geometrical center cannot be obtained by direct measurement. In this work, a new mathematical algorithm was developed to evaluate the base circle dimensions by measurement of only the teeth profiles. Measurement of the outer diameter is not required nor is the prior knowledge of any gear dimension such as its module or pressure angle. The evaluated base circle dimensions are then used to compute remaining dominant gear dimensions including its pressure angle. The developed approach was tested on an ideal gear model then applied to the flank points obtained by measurements performed on a Coordinate Measuring Machine (CMM) and by photogrammetry (PG). The experimental results were compared to those measured using a gear roll tester (GRT) and were found to be in very good agreement. The methodology and measurement procedure presented in this work are distinguished by their ability to measure the actual gear dimensions regardless of any tooth modification made to the profile or addendum during manufacturing. This makes the proposed work well-suited for reverse engineering and rapid prototyping reverse calculations.

Experimental Evaluation of Gas-Dynamic Conditions of Heat Exchange of Stationary Air Flows in Vertical Conical Diffuser

Conical diffusers are widely used in technical devices (gasifiers, turbines, combustion chambers) and technological processes (ejectors, mixers, renewable energy). The perfection of flow gas dynamics in a conical diffuser affects the intensity of heat and mass transfer processes, the quality of mixing/separation of working media and the flow characteristics of technical devices. These parameters largely determine the efficiency and productivity of the final product. This article presents an analysis of experimental data on the gas-dynamic characteristics of stationary air flows in a vertical, conical, flat diffuser under different initial boundary conditions. An experimental setup was created, measuring instruments were selected, and an automated data collection system was developed. Basic data on the gas dynamics of air flows were obtained using the thermal anemometry method. Experimental data on instantaneous values of air flow velocity in a diffuser for initial velocities from 0.4 m/s to 2.22 m/s are presented. These data were the basis for calculating and obtaining velocity fields and turbulence intensity fields of the air flow in a vertical diffuser. It is shown that the value of the initial flow velocity at the diffuser inlet has a significant effect on the gas-dynamic characteristics. In addition, a spectral analysis of the change in air flow velocity both by height and along the diffuser axis was performed. The obtained data may be useful for refining engineering calculations, verifying mathematical models, searching for technical solutions and deepening knowledge about the features of gas dynamics of air flows in vertical diffusers.

Designing and testing a heat pump unit for drying, low-temperature processing, and storing of food products

The use of heat pumps makes it possible to reduce energy consumption in drying processes. This study addresses the problem of efficient use of a heat pump for drying, low-temperature processing, and storage of food products. The object of the study is a heat pump unit capable of operating under the drying mode or under the refrigeration processing and storage mode. Studies have been conducted to design an experimental unit, as well as to improve the energy efficiency of the cooling system. The unit includes a single-stage freon compressor, two air condensers, a water-cooled coil heat exchanger-precondenser, an air evaporator, a thermostatic valve, axial fans, and a unit control system. It has been experimentally established that, depending on the temperature level of condensation of the refrigerant (from +20 °C to +50 °C), the increase in specific cooling capacity with the heat exchanger-precondenser turned off is from 82 kJ/kg to 135 kJ/kg, and with it turned on – from 98 kJ/kg to 143 kJ/kg. In this case, the specific work of compression of refrigerant vapors in the compressor with the heat exchanger-precondenser switched off changes from 36 kJ/kg to 18 kJ/kg. And when it is switched on – from 32 kJ/kg to 10 kJ/kg. That is, the reduction in specific energy consumption is from 4 kJ/kg to 8 kJ/kg, which indicates the advisability of including the precondenser in the installation scheme. In the installation, refrigeration treatment and storage of the product can be carried out in the temperature range from –20 °C to +20 °C and drying – from +10 °C to +40 °C. Under such modes, it is possible to obtain high-quality products with long shelf lives. The results could be used to improve the designs and optimize the operation of heat-transfer drying units and their engineering calculations

Инженерный расчет гибких оболочек лесосплавных опор

Currently, the issue of delivering wood raw materials from remote forest areas, where the largest volumes are located, is relevant. Often, this delivery is economically justified only when using a network of medium and small rivers with the use of environmentally friendly technologies. On such rivers, it is preferable to use mobile anchors, in particular shore fillable ones, for fixing timber-rafting objects. A description has been given of a new modification of such an anchor, which differs from the prototype by a container having a flexible shell. This allows to significantly reduce the material consumption for manufacturing the container, the dimensions of the anchor in the transport position, and to produce anchors of any realistic size. The choice of the most rational option for such a container implies the scientific justification of its parameters. The aim of the study is to develop a scientific basis for this justification. Analytical formulas have been theoretically obtained for determining the basic geometric characteristics of the cross-section of the container under consideration. These formulas are useful in scientific research, but their application is very problematic in practical engineering calculations. This is due to the dependence of the specified characteristics on elliptic integrals and parameters, which are very difficult to measure in engineering practice. Having performed calculations using these formulas for a single cross-sectional area, we have obtained its specific geometric characteristics for various shapes, i.e. for various width-to-height ratios of a container to be filled. The results of the calculations have been approximating dependencies linking the named characteristics with the specified ratio, which is called the shape factor. Multiplying the specific characteristics by the square root of the cross-sectional area gives the absolute values of the corresponding characteristics. As a result, we have obtained formulas convenient for practical use, allowing to determine the width and height of the container to be filled, the width of its base, the perimeter of the cross-section, the heights of the zero pressure line and the extreme lateral point of the cross-section above the base of the container. The accuracy of calculations based on these and analytical formulas is almost the same. A formula for determining the specific tension of a flexible container shell has been obtained. The nature and degree of influence of the shape factor and length of the container on its other geometric characteristics have been established. An algorithm for substantiating the key parameters of a container to be filled with a flexible shell has been developed using the described results.

Large-scale annotation of biochemically relevant pockets and tunnels in cognate enzyme–ligand complexes

Tunnels in enzymes with buried active sites are key structural features allowing the entry of substrates and the release of products, thus contributing to the catalytic efficiency. Targeting the bottlenecks of protein tunnels is also a powerful protein engineering strategy. However, the identification of functional tunnels in multiple protein structures is a non-trivial task that can only be addressed computationally. We present a pipeline integrating automated structural analysis with an in-house machine-learning predictor for the annotation of protein pockets, followed by the calculation of the energetics of ligand transport via biochemically relevant tunnels. A thorough validation using eight distinct molecular systems revealed that CaverDock analysis of ligand un/binding is on par with time-consuming molecular dynamics simulations, but much faster. The optimized and validated pipeline was applied to annotate more than 17,000 cognate enzyme–ligand complexes. Analysis of ligand un/binding energetics indicates that the top priority tunnel has the most favourable energies in 75% of cases. Moreover, energy profiles of cognate ligands revealed that a simple geometry analysis can correctly identify tunnel bottlenecks only in 50% of cases. Our study provides essential information for the interpretation of results from tunnel calculation and energy profiling in mechanistic enzymology and protein engineering. We formulated several simple rules allowing identification of biochemically relevant tunnels based on the binding pockets, tunnel geometry, and ligand transport energy profiles.Scientific contributionsThe pipeline introduced in this work allows for the detailed analysis of a large set of protein–ligand complexes, focusing on transport pathways. We are introducing a novel predictor for determining the relevance of binding pockets for tunnel calculation. For the first time in the field, we present a high-throughput energetic analysis of ligand binding and unbinding, showing that approximate methods for these simulations can identify additional mutagenesis hotspots in enzymes compared to purely geometrical methods. The predictor is included in the supplementary material and can also be accessed at https://github.com/Faranehhad/Large-Scale-Pocket-Tunnel-Annotation.git. The tunnel data calculated in this study has been made publicly available as part of the ChannelsDB 2.0 database, accessible at https://channelsdb2.biodata.ceitec.cz/.

Autonomous trajectory planning method for aircraft based on ripple diffusion algorithm

Aiming at the problem that route optimization in dynamic continuous airspace (non-discrete road network) is difficult to ensure optimality and has low computational efficiency, a non-circular ripple diffusion algorithm is proposed. Firstly, considering the influence of time-varying airflow and obstacle area in dynamic airspace, the airspace wind speed model, route network and dynamic network weight model are established, and 6 airspace environments and 4 road network structures with the influence of time-varying airflow and obstacle area are constructed. Then, the effects of traditional dynamic path optimization algorithm, co-evolutionary path optimization algorithm and non-circular ripple diffusion algorithm on route optimization are compared in 1000 experiments, taking the optimized path length, flight time and calculation time as indicators. The simulation results show that the traditional dynamic path optimization algorithm has the worst effect under the three indicators, and the calculation time of non-circular ripple diffusion algorithm is significantly less than that of the other two algorithms, which effectively improves the engineering calculation efficiency.

Hierarchical Engineering on Built‐In Electric Field of Bimetallic Zeolitic Imidazolate Derivatives Towards Amplified Dielectric Loss

AbstractConstruction of built‐in electric field (BIEF) in nanohybrids has been demonstrated as an efficacious strategy to boost the dielectric loss by facilitating oriented transfer and transition of charges, thus optimizing the electromagnetic wave absorption property. However, the specific influence of BIEF on interface polarization needs to explore thoroughly and the BIEF strength should be further augmented. Herein, several dielectric systems incorporated Mott–Schottky heterojunctions and hollow structures are designed and constructed, where bimetallic zeolitic imidazolate framework are employed to derive Cu‐ZnO Mott–Schottky heterojunctions, and hierarchical structures and BIEF are further enriched by introducing hollow structure and reduced graphene oxide. The well‐established “double” BIEF verified by theoretical calculation and hollow engineering can regulate the conductivity, and enhance the polarization relaxation effectively. Especially, there always coexisted both enhanced charge separation and reversed charge distribution in this “double” BIEF, boosting the interface polarization. Attributing to the synergy of well‐matched impedance and amplified dielectric loss, the obtained hybrids exhibited superior absorption (reflection loss of −46.29 dB and an ultra‐wide effective absorption bandwidth of 7.6 GHz at only 1.6 mm). This work proves an innovative model for dissecting dielectric loss mechanisms and pioneers a novel strategy to explore advanced absorbers through enhancing BIEF.

The impact of fire source location on hot gas layer temperature in multi-compartment pre-flashover fires: Analysis and semi-empirical model development

A numerical study of a two-room structure (multi-compartment) subjected to fire in the inner room was carried out, employing the CFD (Computational Fluid Dynamics) software called FDS (Fire Dynamics Simulator), to (i) analyze the influence of the fire source position on the hot gas layer temperature, Tu, and its behavior in a multi-compartment fire, and (ii) develop a semi-empirical engineering calculation model to predict Tu in the adjacent room to a pre-flashover well-ventilated fire room, taking into account the fire source position. The results showed that when the fire origin occurs close to walls or elevated above the floor level, a reduced air entrainment is observed in the fire plume and flame, causing an increase in the Tu and a reduction of the smoke production in the fire room. This reduction in the smoke production led to a lower increase in the Tu of the adjacent room in relation to the case when the fire source was at the center of the fire room. It was also observed that the Tu in both rooms was inversely proportional to the ventilation factor (A.H0.5), with a significant increase observed as the ventilation factor decreases, depending on the fire source position. Furthermore, a semi-empirical engineering calculation model was developed to predict the Tu in the adjacent room, considering different fire source locations at ground level and elevated. The model was validated against experimental data from the literature, showing a good agreement (deviation of ≈20 %), thus demonstrating its applicability to other cases.

Optimization of time, effort, and costs for well planning using standardization and automation of the well design process on a cloud-based solution

Abstract The current well planning process for operators is capital-intensive that takes time and has a lot of discrete, disconnected steps. Well planners and engineers dedicate a significant amount of time and effort to analyze sub-surface and offset well data for trajectory planning, casing policy selection, casing design, torque & drag, hydraulics, time & cost analysis etc. For development wells and unconventional wells, it is a common scenario for drilling engineers to have a very clear understanding of how the well design shall look like as the oil & gas field is extremely well familiar. As an initial step towards standardization, a review and study of several well design processes were performed by interviewing several engineers, all around the globe. The study revealed that even though every engineer had their own way of working, there was an inherent workflow that could be standardized. This standardized workflow was then outlined with user experience development techniques to cater to the generic steps that well planners, engineers and managers had described. With implementation of this standardized workflow and UI/UX supported process, the next step was to build a cloud native solution which supports micro-services-based engineering calculations in the backend. This allowed to implement speed and scalability in the solution which can cater to various personas in a team. The next step was to automate the process for a development field. This was achieved by applying checkpoints in the workflow to identify an exploratory well vs. a development well, before calling a microservice. For a development field, the microservice architecture identifies the design aspects of an existing well and incorporates similar well trajectory turn points, casing policy, casing design, BHA, fluids, operational parameters etc. while honoring the surface hole location, targets, and datum reference of the new wells to be planned. This technique helped to not only automate the engineering calculations but also speed up the entire process of designing each well in under a minute. Apart from engineering calculations, a planning workflow is never complete without team governance, approvals from peers and supervisors, testing various scenarios and creating reports. As these tasks are an inherent part of the planning cycle, they were also incorporated in the workflow. The UX design process techniques ensured that these supplementary tasks were a part of the main workflow and did not interfere with the calculations. The solution has shown a tremendous increase in the work efficiency of user by reducing the planning efforts from days to minutes. The users can now focus on wells using management by exception as the entire design process can be automated. This also eliminates any unnecessary data entry and avoids errors.

Original Orthorhombic Tetrahedral-Trigonal Hybrid Allotropes Cn (n = 8, 10, 12, 14) with Ethene–Like and Propadiene–Like Units: Crystal Engineering and Quantum Mechanical Calculations

Original Orthorhombic Tetrahedral-Trigonal Hybrid Allotropes Cn (n = 8, 10, 12, 14) with Ethene–Like and Propadiene–Like Units: Crystal Engineering and Quantum Mechanical Calculations

Effects of the Characterization Methods of Heptane Plus Components (C7+) on the Phase Behavior of Volatile Fluids

For reservoir fluids with strong volatile tendencies, such as gas condensate and volatile oil, the determination of the characteristic parameters of the equation of state has a great influence on the fluid phase behavior and subsequent reservoir engineering, production engineering, and surface facilities design calculations. However, the process of characterizing reservoir fluid lacks a unified and standardized procedure, and the methods are largely empirical and rather complicated. In this paper, three main stages are defined for the characterization of the equation of state parameters for these volatile reservoir fluids, including (1) determining the C7+ distribution, (2) calculating the equation of state parameters for the C7+ single-carbon component, and (3) lump components. The typical calculation methods in each step and their effects on the fluid phase behavior calculations are quantitatively analyzed and compared. Finally, the workflow and the suitable characterization methods for gas condensate and volatile oil phase behavior calculations are selected. The results show that C7+ distribution and C7+ single carbon component properties have a greater influence on the phase behavior prediction of condensate gas and volatile oil, while the lumping of C7+ single carbon component has relatively little influence.

Determination of hydrostatic pressure on the plane surface of an arbitrary non-simmetrical form by the three-command method K123

Competitive struggle in the conditions of wide access to unlimited amounts of information and computerization of all branches of production and services imposes strict requirements on specialized knowledge, practical skills and general mathematical culture of future engineers. The online program of modern multivariate engineering calculation of the problem of determining the force of hydrostatic pressure on an element of a flat asymmetric surface with a curvilinear face is presented - https://www.k123.org.ua/jeh5.html. Algorithms are implemented according to the author's method of three commands K123 (c) Yu.D. Kopanytsia (hereinafter the K123 method). A client-server solution based on CGI technology with a web form for inputting source data has been implemented. The results of the online calculation were performed according to the new analytical dependencies obtained on the basis of the author's method K123. In parallel, the numerical algorithms of the author's method of three K123 commands and the conclusions of the corresponding calculations in tabular form were implemented. Realized generation of graphics by the server program based on the coordinates of the points obtained by iterative calculations according to the algorithms of the numerical implementation of the K123 method. The relative error of iterative calculations and the estimation of the accuracy of the result are automatically determined based on the proposed exact analytical dependencies.

Structural and Parametric Synthesis of a Hybrid Repetitive Control System for Uncertain Multi-Mode Plant

Article deals with the problem of constructing a hybrid adaptive-robust repetitive control system for one class of a MIMO plants which operating with structural and parametric uncertainty and constant action of an external disturbances. A procedure for structural and parametric synthesis of a control system is proposed. At the structural synthesis stage with the help of hyperstability criterion the authors are developing a decentralized combined controller. After that using the method of continuous models the authors are built a continuous-discrete control system. The main feature of a control loop structure synthesis stage is to ensure the validity of V. M. Popov’s integral inequality. For this purpose, the authors determining the special estimates that guarantee positivity for nonlinear non-stationary part of the system under consideration. At the system’s parametric synthesis stage the authors are use the environment of engineering and technical calculations "Matlab — Simulink" to perform optimization modeling of the continuous and hybrid repetitive control systems. This action is carried out using one of the functional optimization methods — a genetic algorithm. Authors use the criterion of generalized operation for automatic control systems to form the functionality for assessing the quality of the proposed system. At the simulation stage initially for continuous repetitive system it was searched its controller parameters which ensure the minimum value of the specified functional. Then, with a given discretization step of the control loop elements, the hybrid periodic system was optimized in order to improve the quality of its operation.

ELECTRIC PULSE METHOD OF ROCK DESTRUCTION AND BLAST WELLS DRILLING

The paper proposes an electric pulse method for rock destruction and drilling blast holes based on microwave radiation generated by a magneto-cumulative generator. A description of an electric pulse method installation with a magneto-cumulative generator, protected by a Russian patent, is provided. Relationships are given for an engineering calculation method during the periods of mastering a new technology and it is shown that the introduction of an innovative technology based on the proposed electric pulse method will allow us to talk about a low dependence of the efficiency of electric pulse drilling on the strength of rocks.

Thin-walled aluminium waste remelting in circulation circuit with magnetodynamic pump

Modern technologies for remelting thin-walled aluminium waste are considered, and a new method to implement such process is proposed. This made it possible to increase the yield of a suitable remelted product to 83% from the mass of the initial remelting portion. The main idea is to use indirect heating of the charge. This will allow to significantly reduce the irreversible loss of metal due to burning which can reach 60%. In the proposed process, solid waste is melted by overheated melt stream. The movement of such stream is provided by the action of electromagnetic field. For the practical implementation of the offered idea, there was used a magnetodynamic pump (MDP) designed in the Physico-Technological Institute of Metals and Alloys of National Academy of Sciences of Ukraine. The MDP has a significantly higher heat and power factor than electromagnetic pumps of travelling magnetic field which are often used in similar technologies. Mathematical model of the remelting process of aluminium thin-walled and fine charge due to convective heat transfer was developed. On the basis of this model, an engineering calculation of the specific process of remelting used aluminium cans in the liquid aluminium stream was also carried out. The obtained results were used at further conducting a full-scale experiment. There is designed and successfully practically tested the experimental two-chamber circulation circuit with MDP for remelting thin-walled aluminium waste. Recommendations for further development of the proposed process were formulated.Graphical abstract

تحسين علاقة المرهون لضغط نقطة الفقاعة للنفط الخام الليبي

Accurate estimation of crude oil bubble point pressure plays a vital role in many petroleum engineering calculations, such as reserve estimation, material balance, reservoir simulation, production equipment design, and optimization of well performance. The Pb can be measured in the pressure-volume-temperature (PVT) experiments. Nonetheless, the PVT measurements have limitations, such as being costly and time-consuming. In this paper, the Al-Marhoun correlation for bubble point pressure for black oil reservoirs is improved using the linearization of non-linear regression techniques to fit Libyan crudes accurately. A total of 62 PVT data reports taken from various Libyan oil fields were used in the study. The PVT data consist of an oil gravity range of 24.7 ºAPI to 46.8 ºAPI and bubble point pressures of 123 psig to 6100 psig. Statistical error analyses and graphical methods were used to evaluate the original and modified Al-Marhoun correlations. The results showed that the improved Al-Marhoun correlation exhibits significantly lower average absolute error and deviation than the published ones. The correlation coefficient of R2 of the improved Al-Marhoun correlation is 96.70%, and the average percent error (APE) is 0.70% with a standard deviation (SD) of 14.70.

Vaporisation Thermodynamics: Are Triazolium Ionic Liquids a Real Alternative to Popular Imidazolium-Based Ionic Liquids?

New experimental vapour pressures and vaporisation enthalpies of the ionic liquids [2,4-dimethyl-1,2,4-triazolium][NTf2], [2-methyl-4-ethyl-1,2,4-triazolium][NTf2], and [2-ethyl-4-methyl-1,2,4-triazolium][NTf2] were measured using the Langmuir method in combination with the quartz crystal microbalance. New experimental vapour pressures and vaporisation enthalpies of the molecular liquids 1H-1,2,4-triazole, 1-methyl-1,2,4-triazole, 1-ethyl-1,2,4-triazole, and 1H-1,2,3-triazole were measured using the transpiration method. Structure–property relationships between molecular and ionic liquids were studied. These results will facilitate chemical engineering calculations of processes involving ILs.

Estimation of the Reduction Coefficient When Calculating the Seismic Resistance of a Reinforced Concrete Frame Building after a Fire

The consequences of destructive earthquakes show that the problem of analyzing the response of reinforced concrete frames under seismic loads after a fire is relevant. The calculation models used for individual elements and buildings as a whole must take into account the nonlinear properties of concrete and reinforcement. In the spectral calculation method, the nonlinear properties of materials are taken into account by introducing a reduction coefficient to the elastic spectrum. When determining the reduction coefficient, a common deformation criterion is based on the use of the plasticity coefficient. The seismic resistance of a three-span, five-story reinforced concrete frame under four different fire exposure options is considered. The residual strength and stiffness of frame elements after a fire is assessed by performing a thermal engineering calculation in the SOLIDWORKS software for a standard fire. For the central sections of the elements, the highest temperatures were obtained after heating—during the cooling stage. The reduction coefficient is estimated by performing a nonlinear static analysis of reinforced concrete frames in OpenSees and constructing load-bearing capacity curves. Fracture patterns and damage levels in plastic hinges are analyzed. Based on the numerical modeling of reinforced concrete frames after exposure to fire, it was revealed that the most dangerous scenario is the occurrence of a fire on the first floor of the building. Based on the obtained plasticity coefficients, reduction coefficients were determined in the range of 2.62 to 2.44. The influence of fire on the permissible damage coefficient of a reinforced concrete frame is assessed using the coefficient φK—the coefficient of additional damage after a fire, which is equal to the ratio of the reduction coefficients for the control and fire-damaged frames. Depending on the percentage of damaged structures on the first floor, the following values were obtained: 50% or less—φK = 1.09; 100%—φK = 1.17. The obtained coefficients are recommended to be used when assessing the seismic resistance of a reinforced concrete frame after a local fire.

Density Prediction Model of Binary or Ternary Diesel Fuel Blends with Biodiesel and Ethanol for Compression-Ignition Engine Calculations

Density Prediction Model of Binary or Ternary Diesel Fuel Blends with Biodiesel and Ethanol for Compression-Ignition Engine Calculations