bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimizing the Performance of Construction Companies using Goal Programming Model
Authors: Lam Weng Siew , Lee Pei Fun , Lam Weng Hoe , Bin Bakar Mohd Abidin
Published: December 2023

The construction industry is the driver to the social and economic development of a country. However, the construction industry is capital intensive and resource-reliance with high risk. These characteristics of the construction industry show high vulnerability to financial uncertainties. Therefore, this paper aims to examine the financial performance of the construction companies in Malaysia with goal programming (GP) model. This paper found that ECONBHD, GADANG, and MELATI have high liabilities while GADANG and MELATI have low profits. The powerful GP model has highlighted that the construction companies have high liquidity and solvency risks and could face problems to sustain their operations. This study could help the companies to determine the decremental and incremental values to reach the benchmark values for better financial performance.
Efficient adsorption of Crystal Violet Dye using Coir Pith-Derived Biochar: CCD-RSM modelling and Characterization
Authors: Mathew Tharayil Jeevan , Chinnayan Prakash , Venkat Nivas Nandyala , Babu V Suresh , Murthy C Krishna
Published: December 2023

Effective wastewater treatment techniques are needed to mitigate the effects of water contamination, which is a severe environmental issue. The high adsorption capacity and sustainability of adsorption techniques using biochar from agricultural waste, such as coir pith, have made them appear promising. This work intends to optimize the adsorption procedure utilizing biochar made from coir pith using Central Composite Design (RSM-CCD). The effects of pH, time, adsorbent dosage, and adsorbate concentration were examined on adsorption efficiency. In order to comprehend its structural and elemental characteristics, the synthesized biochar was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). This study focuses on determining the optimal conditions for maximum adsorption efficiency and contributes to environmental engineering by utilizing agricultural waste for water remediation. The results showed that the biochar removed Crystal violet with a remarkable 72% efficiency, highlighting its potential as a powerful adsorbent for water purification.
Mechanical, Durability and Embodied Energy Analysis of Geopolymer Concrete with Fly Ash, GGBFS and Glass Fiber
Authors: L Nishanth , Patil Nayana N. , N A Ganesh
Published: December 2023

Concrete is the second most widely used material next to the basic human needs. As the demand for concrete as a structural material grows, so does the demand for ordinary Portland cement (OPC).Global warming, on the other hand, has emerged as a major concern. Greenhouse gases, such as carbon dioxide emissions caused by human activity, are responsible for global warming. The cement industry is a major contributor to carbon dioxide emissions because it produces the same amount of carbon dioxide as their product. A sustainable alternative material that completely eliminates cement is Geopolymer concrete. This study presents results of an experimental program to determine mechanical, durability and embodied energy of Glass fibre reinforced Geopolymer Concrete contains fly ash and Ground Granulated Blast Furnace Slag (GGBFS) as binder materials in a constant proportion (50%×50%) each. Alkaline liquids to binder ratio by mass as 0.35 with proportion of sodium silicate (Na2SiO3) solution-to-sodium hydroxide (NaOH) 10 Morality solution by mass as 2.5. Coarse and fine aggregates are used in the proportion of 60:40, and Glass fibres are varied by percentages of 0(control mix), 1, 1.5 and 2 by volume of binder material. In the geopolymer concrete composite for the addition of 1% glass fiber compressive strength 21.95%, split tensile strength 52.5% and flexural strength 76.47% were found to be increased when compared with control mix. And results for 1% glass fiber found to be 52.82 MPa, 6.1 MPa and 15 MPa respectively, were as control mix found to be 43.3 MPa, 4 MPa and 8.5 MPa respectively. Highest residual compressive strength was attained for mix with 1% Glass fibres with 52.8MPa before and 48.9MPa after acid exposure. It is observed that least percentage of water absorption was attained for mix with 1% Glass fibres.
Sustainable Approach for Conversion of Building to ‘Zero Energy Building’
Authors: Wadalkar Shruti S. , Patil Vanishri A. , Joshi Deepa A. , Menon Radhika , Sonawane Pratiksha
Published: December 2023

Energy efficient infrastructure is the need of the hour for sustainable development. Zero energy building (ZEB) is one of the concepts towards sustainability. One of the most effective ways to achieve sustainability is to convert existing buildings to zero energy buildings. In this study concept of zero energy building and various retrofitting techniques for conversion of existing building to zero energy is studied in detail. A case study of residential house in rural area has been done for retrofitting in which Building Envelope and Renewable Energy techniques are used for retrofitting. Cost analysis and recovery period of the retrofitting is carried out. The first 24 years are used to recoup the entire expense of the retrofit. Building is used for the remaining 16 years with the advantage of cost savings from retrofitting of Rs. 2, 87,445/-. From case study it is concluded that both the techniques are suitable and cost effective for conversion of residential house into zero energy building.
Performance Assessment of Outrigger System for High Rise Slender Structures
Authors: Rathore Manas , Ansari Mohammad Irshad , Baghel Rahul , Das Piyush , Dewangan Meghal , Verma Aloke
Published: December 2023

High-rise slender structures have become increasingly prevalent in modern urban landscapes due to the demand for efficient land use and sustainable development. However, these tall and slender buildings are susceptible to various structural challenges, including wind-induced vibrations and lateral deformations. To mitigate these issues and ensure the safety and comfort of occupants, outrigger systems have emerged as a popular structural solution. Through a thorough examination of their structural performance, the outrigger systems used in high-rise, slender structures are examined in this study to determine how they behave and how successful they are. In this way, the design base shear for the entire structure is calculated and distributed over its height. Response spectrum analysis employs eigen value analysis to identify natural frequencies and mode shapes. While time history analysis is a method for figuring out the precise reaction of a structure as a function of time, it is used to compute the peak response. The equation of motion is typically numerically integrated step by step to calculate the response history. This paper explores the impact of earthquakes on outrigger systems in high-rise slender structures. Outrigger systems, which typically consist of horizontal beams connecting the core and the perimeter of the building, play a crucial role in mitigating the effects of seismic activity. These systems provide stiffness and strength to the structure, limiting lateral sway and reducing damage during an earthquake. This paper innovative technologies and construction techniques that enhance the earthquake resilience of outrigger systems. This includes the use of advanced materials, base isolators, and dampers to improve the performance of high-rise slender structures during seismic events.
Wastewater Treatment in Constructed Wetlands by Phytoremediation Technique
Authors: Raju Hemadri Prasad , Vijaya Kumar Mamilla , Partheeban Pachaivannan
Published: December 2023

Water is the most required element next to air for terrestrial living being. Though the water is everywhere but no direct use is possible as the fresh water is getting contaminated through various human activities. The conventional treatment methods using activated sludge process, attached growth systems such as trickling filters, rotating biological contactors, aerated lagoons and stabilization ponds are normally practiced in many places with each one having its own merits and demerits depending on space availability, energy requirements etc. An alternative solution called phytoremediation method can save energy requirements to the great extent but space required will be more and it can be used advantageously where space is not a constraint. This method involves using plants to absorb and metabolize pollutants found in wastewater, including nutrients such as nitrogen and phosphorus, heavy metals and other organic and inorganic contaminants. In this study, sewage is passed through a bed of plants, which takes up nutrients and contaminants while releasing oxygen during their photosynthesis process. This promotes the growth of beneficial bacteria that further break down pollutants. In the present work, Spider lily (Hymenocallis littoralis) and Heliconia (Heliconia psittacorum) are two species of tropical plants used in constructed wetlands and that have shown potential in the treatment of sewage. Conducted the performance studies on both plants separately. The efficiency achieved with spider lily plants Heliconia plants are 87.2% and 79.6% in BOD removal respectively. These systems are also relatively low-cost and require minimal maintenance, making them a viable option for wastewater treatment in areas where conventional treatment systems may be too expensive or impractical.
Synthesis and Characterization of Hybrid Polymer Composite: An Experimental Approach
Authors: Gulia Vikas , Jatti Savita V. , Jatti Vinay S. , Maheshwari Shruti , Solke Nitin S.
Published: December 2023

Hybrid Polymer composites have recently emerged as one of the most important fields for researchers owing to their weight reduction benefits, corrosion resistance, design flexibility, manufacturing developments, multidiscipline applications, and sustainability. There are many types of hybrid polymer composites, one of which is made up of combining natural polymers and synthetic polymers and the other which is made up of combining natural-natural polymers. Hybrid composites also consist of nanocomposites, molecular composites, nanomaterials, and mesoscopic materials. In present study, hybrid polymer matrix composites reinforced with copper particulate were prepared using polycarbonate (PC), acrylonitrile butadiene styrene (ABS), and polycarbonate plus ABS. Injection moulding process employed to synthesize the hybrid polymer composite. Tensile strength, electrical conductivity and thermal expansion coefficient were measured as per the ASTM D638, ASTM D 257 and ASTM D 696, respectively. 50% Copper + 50% Polycarbonate outperform other combinations in terms of tensile strength, electrical conductivity, and coefficient of thermal expansion. In addition, scanning electron microscopy was also used to understand the homogenous mixture of hybrid polymer composites.
Evaluation of the biopositivity of the subgrade
Authors: Shestakov Nikolai , Tkach Evgeniya , Filimonova Yulia , Khokhlova Natalia
Published: December 2023

A large amount of industrial waste generates a certain interest in the possibilities of their use in the road industry. The article considers the possibility of using copper smelter slag as a man-made material for the construction of an embankment of roadbeds. The results of the performed elemental composition of the studied slag are presented, as well as micrographs characterizing its structure. As a result of the research, it has been established that copper smelter slags are valuable raw materials with weak binding properties and are potentially applicable for obtaining technogenic soils with high physical, mechanical and operational properties for highways.
Computational-experimental method for determining the height of steel fiber sedimentation in Ultra-High Performance Self-Compacting Concrete
Authors: Soloviev Vadim , Matiushin Evgenii
Published: December 2023

The uniform distribution of steel fibers in self-compacting Ultra-High Performance Steel Fiber Reinforced Concrete is one of the factors that determine the properties of the hardened material. In self-compacting concrete mixes characterized by low yield stress and plastic viscosity, steel fibers can settle under gravity, which can lead to a decrease in strength. In this study, a computational-experimental method is proposed for determining the height of steel fiber sedimentation, as well as the segregation index of a steel fiber reinforced concrete mixture. Mixtures were tested with a superplasticizer content of 1, 1.3, and 1.6% with a slump flow diameter of 288, 356, and 378 mm. According to the results of calculations performed according to the proposed method, it was found that the height of steel fiber sedimentation is 3.1, 5.9, and 22.8 mm in mixtures with a plasticizer content of 1, 1.3 and 1.6%. The calculated value of the segregation index of the steel fiber reinforced concrete is quite close to the experimental one with a correlation coefficient of 0.998. Based on the results obtained, a criterion was proposed for determining the maximum allowable height of fiber sedimentation, taking into account the actual height of the concreted structure, which can be used in the concrete mix design.
Dynamics of rutting because of road surface wear
Authors: Lushnikov Nikolay , Lushnikov Pyotr , Nebratenko Dmitry , Nikolaevsky Vladimir
Published: December 2023

The results of the road surface wear observations in different periods of the year on one of the highways are considered in the paper. Reducing the rate of wear of road surfaces by car tires is an urgent task for the Russian Federation, since the state incurs huge losses owing to this. A set of measures is necessary to reduce the wear of road surfaces, especially during the period when studded tires are used on the cars. Additional researches related to the specifics of our country are required for developing such activities. Foreign measures cannot be applied without significant modification, since each country has its own approach to solving this issue. It is necessary to fulfill a research of wear mechanisms in the “car tire – road surface” system and obtain quantitative dependences of the wear rate on some external factors to substantiate organizational and technical measures aimed at reducing road surface wear. The article presents the results of observations of the rate of increase in the track and the road surface roughness degradation are presented in the paper. The following quantitative indicators were determined as a result of observations: the rate of change in rut depth due to the road surface wear; spectral density of the microprofile of road surface roughness during its wear. Preliminary conclusions were drawn about the mechanism of road surface wear and proposals were formulated for the trend of further researches based on the results of field studies.
The role of energy-efficient renovation in the sustainability of cities and settlements: European experience
Authors: Budakov Alexey , Safronova Natalia , Nikolaev Alexander Alexandrovich , Vu Le Quyen , Laamarti Yuliya A.
Published: December 2023

Building renovation is one of the industries with the largest investment gap. To achieve the proposed climate target of 55% by 2030 in the EU, additional investments of around €275 billion will be required annually. In the housing sector, the lack of simple, attractive and easily accessible state incentives for renovation and the absence of common financial products are often the main obstacles. The experience of energy-efficient renovation in European countries allows for calculated decisions when modeling housing policy and achieving sustainable development goals. To support this, some countries have already introduced minimum common efficiency requirements that apply from a certain date or at certain points in the building's life cycle. Such requirements form the basis of companies' expectations and work best along with reliable energy performance certificates and reliable financing. As for residential buildings, insufficient understanding of energy consumption and energy saving is seen as an important barrier for more participants in open public consultations on renovation work than any other obstacle. Various interests of building owners and users, differences in opinions among different owners, and difficulties in planning renovation work are also major obstacles to the formation of sustainable cities and settlements.
A Numerical Study on the Influence of Anchored Diaphragm Walls on Adjacent Buildings during Deep Excavation Construction
Authors: Nguyen Van-Hoa , Nikiforova Nadezhda Sergeevna , Nguyen Duy-Duan , Nguyen Tien-Hong
Published: December 2023

The aim of this numerical study is to investigate the impact of anchored diaphragm walls on adjacent buildings during deep excavation construction, considering five typical geological conditions in big cities of Vietnam. To achieve this, the behavior of anchored diaphragm walls systems is simulated using the Plaxis 2D program. By conducting these analyses, the study seeks to provide important insights into the behavior of anchored diaphragm walls and their effects on nearby buildings during deep excavation construction.
Stress-strain state of base strip foundation strengthening with a structure combined with a blind area
Authors: Yarkin Viktor , Lobacheva Nataliia , Denisova Daria
Published: December 2023

The article discusses a modified strengthening construction of the strip foundation, combined with a blind area, which makes it possible to increase the efficiency of this strengthen method. The results of experimental studies to verify the operability of structural protection measures are presented, and also to obtain the basic regularities of the stress-strain state of the foundation construction of a frameless building operated on an unevenly deformable base. The results of numerical studies for two cases are presented: strip foundation without strengthening construction, and strip foundation with strengthening construction. As a result of numerical studies, the dependences of the average vertical movements of the footing of the strengthened and non- strengthened foundation on the load, as well as its full bearing capacity in both cases, were obtained. The most effective application of this strengthening construction is in conditions in which the maximum critical pressures can be reached on certain sections of the strip foundation. For example, with significant uneven settlements along the length of the strip foundation.
Hydraulic Analysis of the Urban Drain System
Authors: Volgina Lyudmila V.
Published: December 2023

Analysis efficiency operating drain sewer systems (DSS) is a part of urban water management. Two basic parameters flooding and sediment formation with average annual precipitation and with rains varying intensity are considering. Dealing with hydraulic problems, modelling focus lies on non-pressure systems with two-phase flows. The main requirement in the design of gravity collectors is the flow rate with self-cleaning velocity. The initial data for hydraulics calculation DSS is the flow rate in hole system and geometrical characteristic of the each elements. The average velocity in local tube depends on average flow rate and the cross-sectional area. For calculation, cross-section area needs to estimate depth of flow, which can be find only in situ. The average velocity was found for each element of the system by combining the two matrices. The first contains the initial data of the working collector, and the second contains all possible velocities and depth of the collector with such geometric characteristics. Verification of the proposed model was carried out using data from the standards and from engineering systems in Moscow. Maps with the coordinates of the tube outlet in the considered part of Moscow where the flooded collectors and collectors with sediment were compiled.
Safety cages efficiency during ascent and descent on vertical ladders
Authors: Vasilenko Vasiliy Vladimirovich , Zherdev Kirill Valerievich
Published: December 2023

Issues of ensuring the safety of working on height do not lose their relevance. Civil engineering is in the first place of the amount of injuries and deaths. It accounts for 17% of the structure of the main types of economy activity. The main reason of injuries is the fall from a height (30.5% of all injuries) More than 40% of accidents are lethal or cause partly or complete inability to work. The paper considers safety during ascent and descent on caged ladders, representing a way of collective protection. The construction of vertical ladders, arc cages and the mechanic of worker ascent are considered. Preliminary kinematic model of human fall has been considered during tests, using falling mannequin on caged ladders, with additional safety systems and without them. The analysis show, that caged ladders cannot provide enough protection and create an imaginary protection threat especially when the construction has three vertical bars, which has been set and tested. There is a high probability of falling on the ground or another platform. The paper shows, that cages are not as safe as personal protection equipment, installed on ladders. Some normative documents about vertical ladders allow falling from height less than 10m, which raises many questions about the safety of using that standards.
Calculation of energy consumption in the construction of low-rise buildings
Authors: Korol Elena , Zhuravleva Anastasia
Published: December 2023

Low-rise housing construction is a promising segment of the development of the housing construction industry. One of the priority tasks of state policy in advanced countries is to increase energy efficiency in various sectors of the national economy. In the general life cycle, the stage of construction of buildings, despite a relatively short period of time, is a large consumer of energy resources, so the issue of energy saving during the construction of buildings becomes especially relevant. The predominance of manual labor, as well as the use of low-power construction equipment, significantly affects the reduction of energy consumption at the stage of construction of low-rise residential buildings. However, the widespread use of various technologies for low-rise construction and, as a consequence, differences in design and technological solutions affect the specifics of the use of construction machines and mechanisms. From the standpoint of rational energy consumption, it is advisable to take into account the costs of fuel and energy resources at the construction planning stage. The article proposes tools for calculating the consumption of fuel and energy resources during work on a construction site, identifies the most energy-intensive technology for low-rise housing construction.
Architectural and planning features of terracing of multi-storey residential buildings on flat terrain
Authors: Sarkisyan David Armenovich , Melnikova Irina Borisovna
Published: December 2023

The paper deals with terracing techniques for multi-storey residential buildings on flat terrain. The relevance of terracing application in modern architecture is substantiated, as this architectural and planning method allows not only to radically change the visual qualities of a residential building, but also to enhance the planning qualities of apartments, supplementing them with additional individual open spaces. The paper outlines the classification of terracing techniques for multi-storey residential buildings from the point of forming their volumetric and spatial composition. An analysis of different terracing methods with examples from current world practice is presented. The presented terracing techniques demonstrate the great potential of this method in design practice both for achieving expressive architecture of buildings and complexes, and for improving the quality of urbanized residential environment in general.
Gridshell Structures in Moscow: A Review of Design, Construction, and Applications
Authors: Sokolova Lidia Nataly Somarriba , Ermakova Evgenia Vladimirovna
Published: December 2023

Gridshell structures have gained significant attention in recent years due to their remarkable architectural flexibility, sustainable construction techniques, and aesthetically pleasing designs. This article explores the application of gridshell structures in the city of Moscow. The study begins with an introduction to the concept, construction methods, and advantages of gridshell structures. It further investigates their utilization in various architectural projects in Moscow, highlighting their contributions to the city's urban landscape and sustainability goals.
Urban Regeneration: What Are the Architectural Trends?
Authors: Sedova Anastasiia , Celani Alberto
Published: December 2023

Many cities suffer overpopulation and the presence of obsolete underutilised areas which sometimes are located in central city areas. Urban regeneration is an effective tool to “breathe life” into such spaces. Urban regeneration has become common in the last few decades; there are many successful cases of implemented or planned urban regeneration worldwide. The Authors of this paper study such best practices in order to identify current architectural trends in urban regeneration, which contribute to the creation of more green, resilient, sustainable, safe, accessible urban areas. The case studies shown in this article are the winning projects of the C40 Reinventing Cities competition, which is a global competition that was established to accelerate the development of decarbonised and resilient urban regeneration across the globe. This paper contributes to the knowledge through highlighting five architectural trends which are the most common and crucial for facilitating positive urban regeneration processes.
Generation of a low-temperature plasma in a nozzle to initiate ion-cluster reactions in jets of mixtures of methane with a buffer gas
Authors: Khudozhitkov Vitalii , Zarvin Alexandr , Kalyada Valerii
Published: December 2023

We have considered the option of generating cluster ions directly at the nozzle by initiating an electric discharge. Here, a low-temperature plasma in the flow is formed as a result of the outflow of a partially ionized gas. Conditions for the formation of clusters in the presence of excited particles are provided downstream. To implement this generation option, a scheme for creating an effective discharge in the diffuser part of a supersonic nozzle was proposed and implemented. The diagnostic system of the LEMPUS-2 gas-dynamic facility was adapted to register processes in a supersonic flow of ionized gas with clusters. Molecular nitrogen, which is weakly condensing under experimental conditions, was used as the primary reference gas. The methods of molecular beam mass spectrometry were used to study gas mixtures consisting of 20% methane in an inert carrier gas. Highly condensable argon and practically non-condensable helium were used as carrier gases. It was found that when using the ionized particle selection system for detection, only methane monomers and dimers are registered in mixtures with argon, whereas in mixtures with helium larger clusters are registered. A version of the explanation of the detected dependencies was presented.
Features of the flow structure in the boundary layer of a V-shaped flying wing model with controls and a distributed electric propulsion
Authors: Alpatskiy Nikita , Pavlenko Alexander , Melnik Elizaveta , Kaprilevskaya Valeria , Zanin Boris
Published: December 2023

The study was carried out on a model of a small-sized aircraft of the type of a flying wing, which has a V-shape in plan. The structure of the flow on the wing surface was studied depending on the angle of attack and deflection of the controls. Experiments were carried out to study the influence of the work of the distributed electric propulsion on the flow structure on the wing surface. As a result, flow patterns were obtained using the “soot-oil” visualization method for each flow regime.
Experimental study of the process of gravitational settling of a monodisperse cluster of drops under the influence of an external air flow
Authors: Arkhipov Vladimir , Basalaev Sergey , Zolotorev Nikolay , Perfilieva Ksenia , Usanina Anna
Published: December 2023

A technique and an experimental setup for studying the dynamics of gravitational settling of a monodisperse cluster of distilled water droplets under external influence of an air flow are presented. A qualitative picture of the dynamics of deposition of a monodisperse cluster of 60 drops is presented. It is shown that with an increase in the speed of the ascending airflow from 0 to 1 m/s, the average sedimentation velocity of a monodisperse droplet cluster decreases from 3.8 m/s to 2.8 m/s. The results of comparing the deposition rate of a cluster and individual droplets included in it are presented.
Regimes of falling liquid film flowing over the vertical cylinder at contact angles up to 90° and Reynold number 50
Authors: Sakhnov Alexey , Volodin Oleg , Pecherkin Nikolay , Pavlenko Alexandr
Published: December 2023

The paper presents 3D numerical modeling of spreading dynamics of R21 (mol. fraction: 0.9) and R114 refrigerant mixture film. We considered an outer flow along a round vertical cylinder at Reynolds numbers of 50 and contact angles of 10°, 30°, 50°, 70° and 90°. The simulation was performed in OpenFOAM software on the basis of the volume of fluid (VOF) method. We obtained that the contact angle has a key effect on the wetted area due to the change of liquid spreading modes over the cylinder. At that, we distinguished the following flow modes: the stable jet mode, the cascade jet mode, the jet-droplet mode and the drying mode. These modes are similar ones for horizontal tubes. In some flow modes over the vertical cylinder, we demonstrated the existence of the back liquid flow between jets, directed against gravity.
Numerical study of pressure profiles in an annular combustor and a manifold during continuous spin detonation of nonstoichiometric hydrogen-air mixtures
Authors: Simonov Evgeny
Published: December 2023

A closed mathematical model of continuous spin detonation of nonstoichiometric hydrogen-air mixtures in a quasi-three-dimensional unsteady gas-dynamic formulation taking into account the reverse effect of the oscillation processes in the combustor on the mixture injection system is utilized in pressure profiles in the combustion chamber and in the manifold investigation. Numerical simulations are performed for the flow-type annular combustor 503 mm in diameter with an annular gap of width 18 mm and other geometric dimensions corresponding to experiments. Three-wave mode of continuous spin detonation is calculated and the flow structure is analyzed for the equivalence ratio of 0.6 and the specific hydrogen-air mixture flow rate of 390.6 kg/(s·m2). The static, the mean static and the mean total pressure distributions in the combustor are calculated. The results are validated against experimental data.
Numerical modelling of raw materials atomization and vaporization in a heat carrier gas flow in technical carbon production based on the Euler approach
Authors: Aksenov Andrey A. , Zhluktov Sergey V. , Kashirin Vladimir S. , Sazonova Marina L. , Cherny Sergey G. , Zeziulin Ilia V. , Drozdova Ekaterina A. , Rode Alexandr A.
Published: December 2023

Previously, the authors of this article proposed a 3D Euler-Eulerian model of raw materials spraying and evaporation in the heat-carrier gas flow in the carbon production reactor. The raw materials' droplets fragmentation and evaporation are considered as the carrier and dispersed phase interaction. The continuous phase is a heat carrier gas whose motion is described by the Navier-Stokes equations. Dispersed phase (droplets of raw material and products of its evaporation) motion is described using a non-uniform convective-diffusion equation for the particle concentration. The model was tested with water as a raw material. In this work, hydrocarbons are specified as raw materials. It is proposed next to solve the inverse problem with the target functional providing zero contact of the unevaporated raw materials with the reactor wall. Then the number of solid coke particles in the final product will be minimal. An analysis is made of the unevaporated raw material area sensitivity to the inlet velocity of the heat-carrier gas flow. This parameter has the most impact on the distribution area of the unevaporated raw materials and is assumed to be varied in the optimization problem.
Modelling of pool boiling on the structured surfaces using Lattice Boltzmann method
Authors: Fedoseev Alexander , Salnikov Mikhail , Ostapchenko Anastasiya
Published: December 2023

The process of boiling on spatially structured surfaces is simulated by a hybrid model based on Lattice Boltzmann Method and heat transfer equation. The model permits to study heat transfer at boiling in a wide range of surface superheats for different surface structural characteristics. The regimes of natural convection, nucleate boiling, and transition to film boiling are studied. The boiling curves for the surfaces with different structural and wetting properties are obtained. It was shown that the onset of nucleate boiling occurs at lower wall superheat on the structured surfaces than that on the smooth surface. However, at high wall superheats the heat flux and the critical heat flux at modified surfaces are lower. It was obtained that special modification of both structural and wetting properties of heat exchange surface permits to obtain higher removal heat flux as well as higher critical heat flux.
Effect of SDS concentration on the process of hydrate formation by explosive boiling of liquefied freon 134a in water with SDS volume
Authors: Meleshkin Anton
Published: December 2023

This work is part of a comprehensive study of a method for obtaining gas hydrates, based on the explosive boiling of a liquefied hydrate-forming gas in a volume of water during pressure release. The method shows high efficiency and productivity. Freon 134a is used as a hydrate-forming gas. The paper presents the results of an experimental study on the effect of the concentration of the kinetic promoter sodium dodecyl sulfate (SDS) on the conversion of water into a gas hydrate state. The change in pressure and temperature in the process of hydroformation is shown.
Calculation and analysis of the flamelet library for numerical modelling of the non-premixed combustion of natural gas in a pilot burner
Authors: Krasinsky Denis
Published: December 2023

The flamelet modelling concept has been employed for numerical simulation of the non-premixed combustion of natural gas in a pilot burner of novel type. This prospective laboratory-scale burner device is featured by axial supply of high-speed jet of flue gases, while the fuel (natural gas) and the oxidizer (air) are supplied radially and separately inside the burner chamber. With the use of chemical kinetics mechanism for natural gas (62 species, 398 reactions) the flamelet library has been generated, from its analysis the flame quenching has been determined at the scalar dissipation rate limit of 42 (1/s). From this library the lookup-table of thermochemical solution has been pre-calculated with the presumed beta-function pdf averaging. On this basis the numerical simulation of aerodynamics, heat transfer and the natural gas combustion processes, including soot formation and its effect on radiative heat transfer, has been performed in the considered pilot burner run at the thermal load of 8.8 kW and air excess coefficient of 0.85 (inside the burner body). The distributions of gas species are presented. The predicted NOx emission in exhaust gases is 48.8 mg/m3 for the studied burner regime.
Features of the formation of a flame at a collision of two laminar gas jets
Authors: Kozlov Victor , Litvinenko Yury , Katasonov Mikhail , Shmakov Andrey
Published: December 2023

The results of studies of the interaction process of two colliding axisymmetric microjets of propane/butane mixture with and without diffusion combustion are presented. The outflow of the gas mixture was carried out through round tubes at the same velocities. During the experiment, the transverse position of the tubes was varied while maintaining the angle between them. The features of the formation of the resulting jet depending on the transverse position of the tubes are defined. When the tubes are in the same plane, the resulting jet is formed in a plane orthogonal to it. This process is observed during the interaction of burning and non-burning jets. At increasing velocity of the jets, a region of local gap of the flame front was found.
The effect of the thickness of the liquid layer and the relative humidity of the environment on the condensation growth of microdroplets levitating over a thin layer of liquid
Authors: Shatekova Almira , Zaitsev Dmitry
Published: December 2023

Tests were carried out on levitating microdroplets in a test section comprising a cuvette containing a thin layer of liquid. At the base of the cuvette, there is a round heating element with a diameter of 3 mm that is flush-sealed. We investigated how the size of the droplets changed due to condensation under different conditions, such as the thickness of the liquid layer and the humidity of the surrounding air. Our results showed that increasing the thickness of the liquid layer did not affect the growth of the droplets, but increasing the humidity of the air caused them to grow at a slower rate.
A Comparative Study of Endoderm Differentiation Between Activin A and
Small Molecules
Authors: Li Qiang , Li Jin , Wang Ping , He Xiaoqun , Hong Mingzhao , Liu Feng
Published: December 2023

Small molecules such as ROCK inhibitors (Fasudil) and inducer of definitive
endoderm 1 (IDE1) can promote differentiation of definitive endoderm, but their
effects remain controversial. Therefore, we attempted to verify the effect of
these small molecules on promoting definitive endoderm differentiation and found
that Fasudil or IDE1 alone could not achieve a similar effect as activin A. On
the contrary, CHIR99021 could efficiently promote definitive endoderm
differentiation. Nearly 43.4% of experimental cells were SRY-box
transcription factor 17 (SOX17)-positive under the synergistic effect of IDE1
and CHIR99021, but its ability to differentiate towards definitive endoderm was
still insufficient. Transcriptional analysis and comparison of IDE1 and
CHIR99021 synergistic groups (IC) and activin A and CHIR99021 synergistic groups
(AC) showed significantly down-regulated definitive endoderm markers in the IC
group compared with those in the AC group and the differences between the two
groups were mainly due to bone morphogenetic proteins (BMP4) and fibroblast
growth factor 17 (FGF17). Further single-cell transcriptome analysis revealed
lower expression of BMP4 in SOX17-positive populations, while mothers against
decapentaplegic homolog (SMAD) protein translation signal and FGF17 in the AC
group were higher than that in the IC group. Western blot analysis showed a
significant difference in levels of p-SMAD2/3 between AC and IC groups,
which suggests that regulating p-SMAD2/3 may provide a reference to
improve the differentiation of definitive endoderm.
Intradermal testing and serum allergen-specific IgE-testing in cats
with naturally occurring feline bronchial disease
Authors: Richter Petra , Stursberg Ulrike , Pfeiffer Isabella , Loesenbeck Gerhard , Sauter-Louis Carola , Hartmann Katrin , Mueller Ralf S. , Doerfelt Renè , Schulz Bianka S.
Published: December 2023

Objectives While feline asthma (FA) is considered to be of allergic
origin, the etiology of feline chronic bronchitis (CB) to date is unknown. Aim
of the study was to compare the results of intradermal testing (IDT) and serum
testing for allergen-specific immunoglobulin E (SAT) in cats diagnosed with FA
and CB.

Material and methods Twenty-seven client-owned cats with clinical signs,
suggestive of feline inflammatory bronchial disease (FBD) were prospectively
enrolled in the study. Patients were assigned to 3 groups based on results of
bronchoalveolar-lavage-fluid (BALF)-cytology: FA (n=8), CB
(n=10), or cats with a physiological BALF cytology (PB; n=9). A
standardized IDT for 27 allergens was performed in all cats. In addition,
allergen-specific IgE was measured in serum samples using an
FcεRIα-ELISA. The number of positive reactions in both tests was
compared between groups, and agreement between test results of both tests was
evaluated.

Results Regarding the number of positive reactions, no statistically
significant difference was detected between groups in IDT (p=0.65) and
SAT (p=0.51). When comparing the 2 test systems, a weak correlation was
found for the allergens Tyrophagus putrescentiae (k=0.256),
Dermatophagoides farinae (k=0.276), and rye
(k=0.273). The most commonly observed reactions were to house dust
mites, storage mites, rye and nettle in IDT and to sheep sorrel, storage mites,
and house dust mites in SAT.

Conclusion and relevance IDT and SAT in cats with feline inflammatory
bronchial disease (FBD) cannot be used interchangeably for allergen detection.
Sensitization to environmental allergens can occur in cats with and without
airway inflammation. Therefore, a positive test result should always be assessed
in context with clinical signs and allergen exposure.
Subdermale Hyaluronsäureinjektion zur Behandlung eines
Oberlidentropiums bei einem Kaninchen
Authors: Drießen Freya
Published: December 2023

Das Entropium wird in der Regel chirurgisch therapiert. Gerade bei
älteren Patienten und vor allem bei kleinen Heimtieren besteht
häufig ein nicht unerhebliches Narkoserisiko, welches häufig zur
Ablehnung der chirurgischen Therapie von Seiten der Besitzer führen
kann. Das im Folgenden vorgestellte, 9 Jahre alte Kaninchen litt unter einem
superfiziellen Hornhautulkus und einem Oberlidentropium. Die Lidstellung wurde
mittels subdermaler Hyaluronsäureinjektion (Alayna SG 24
Distinct®, BSC Medical Devices GmbH, München,
Deutschland) ohne Allgemeinanästhesie oder Sedierung erfolgreich
korrigiert. Nach 273 Tagen machte ein Rezidiv eine erneute Injektion notwendig,
die ebenfalls erfolgreich die Lidstellung korrigierte. Ein Entropium am
kontralateralen Auge während des Beobachtungszeitraums machte auch hier
eine Therapie notwendig. Die Anwendung von subdermal injizierter
Hyaluronsäure zeigte sich bei diesem Patienten als insgesamt
komplikationsfrei und erfolgreich.
Alveoläre Echinokokkose bei Mastschweinen in einem
konventionellen Haltungssystem
Authors: Igelbrink Ralf , Frey Tanja , Schwabe Ingo , Prot Manuel , Reimus Fenja , Oehme Rainer , Löwenstein Frederik
Published: December 2023

In einem konventionellen Schweinemastbetrieb in Süddeutschland wurden im
Jahresverlauf 2022 bis zu 100 % der Lebern einzelner Schlachtpartien
wegen parasitärer Läsionen beanstandet. Eine Intensivierung der
Antiparasitenmetaphylaxe mit Fenbendazol zur Bekämpfung von Ascaris
suum im Bestand blieb erfolglos. Im Rahmen einer pathomorphologischen
Untersuchung von 6 Lebern aus 2 Schlachtpartien konnten oligofokale bindegewebig
gekapselte Entzündungen festgestellt werden. Histologisch wurden eine
chronische granulomatöse Hepatitis mit massenhafter Beteiligung von
eosinophilen Granulozyten sowie zentrale parasitäre Strukturen eines
Helminthen nachgewiesen. Die Untersuchung der Leberläsionen mittels PCR
ergab den Nachweis von Echinococcus (E.) multilocularis. Zur
Ermittlung der Eintragsquelle in den Bestand wurden Kotproben von halbwild
lebenden Hauskatzen nahe des Futtermischers und im Stallgang entnommen.
Parasitologisch wurden Cestoden-Eier in den Kotproben nachgewiesen.
Genomfragmente von E. multilocularis konnten mittels PCR aus dem Kot
nicht amplifiziert werden. Im vorliegenden Fall wurden Hauskatzen als
wahrscheinlichste Eintragsquelle in den Bestand vermutet.
Bekämpfungsmaßnahmen zielten auf die Vermeidung des
Parasiteneintrags durch eine Therapie mit Antiparasitika der Hauskatzen ab.
Differentialdiagnostisch konnten mittels PCR und bakteriologischer Untersuchung
keine anderen in Frage kommenden Erreger nachgewiesen werden.
Applicant Perceptions of In-Person versus Virtual Interview Format for Surgical Retina Fellowship
Authors: Besagar Sonya , Patel Shriji , Vajzovic Lejla , Scott Adrienne W. , Ji Xiangyu , Chen Qingxia , Finn Avni
Published: December 2023

Purpose This article compares applicants' perceptions of and experiences with virtual and in-person interviews for surgical retina fellowship.

Methods A survey was distributed via email to all applicants of three vitreoretinal surgery fellowship programs for the 2021 to 2022 and 2022 to 2023 application cycles.

Main Outcome Measures Participants were surveyed regarding cost; burden of scheduling; number of applications and interviews completed; ability to gain a true feel of the program, location, and preceptor; and number of work and surgical days missed.

Results Of 151 applicants contacted, 36 completed the survey (23.8% response rate). Of the respondents, 25.0% attended only virtual interviews, 19.4% attended mostly virtual interviews, 30.6% attended mostly in-person interviews, and 25.0% attended half virtual and half in-person interviews. Average expenditure was significantly lower for applicants with mostly and completely virtual interviews compared with applicants with mostly in-person and half virtual, half in-person (p < 0.001). Applicants with mostly virtual interviews reported a lower ability to gain a true perception of the program and the program location (p = 0.003 and p < 0.001, respectively). There was no difference in burden of scheduling, number of interviews completed, or number of work and surgical days missed. When applicants were asked what type of interview format they would prefer if they could repeat the cycle, those who interviewed mostly in-person largely chose in-person as their preference (72.7%), while participants who interviewed mostly or completely virtually were evenly split between in-person, virtual, and hybrid (p = 0.136).

Conclusion As fellowship programs and institutions decide whether they will return to in-person interviews or maintain a virtual interview format in the long term, they must weigh the lower cost of virtual interviews with the improved ability to gain a more accurate perception of the program and location allowed by in-person interviews, as well as potentially greater satisfaction with the in-person format.
Mod 𝑝 homology of unordered configuration spaces of 𝑝 points in parallelizable surfaces
Authors: Chen Matthew , Zhang Adela
Published: December 2023

We provide a short proof that the dimensions of the mod

p
p

homology groups of the unordered configuration space

B
k

(
T
)

B_k(T)

of

k
k

points in a closed torus are the same as its Betti numbers for

p
>
2

p>2

and

k
≤
p

k\leq p

. Hence the integral homology has no

p
p

-power torsion in this range. The same argument works for the once-punctured genus

g
g

surface with

g
≥
0

g\geq 0

, thereby recovering a result of Brantner-Hahn-Knudsen via Lubin-Tate theory.
On Liouville-type theorems for 𝑘-Hessian equations with gradient terms
Authors: Doerr Cameron , Mohammed Ahmed
Published: December 2023

In this paper, we investigate several Liouville-type theorems related to

k
k

-Hessian equations with non-linear gradient terms. More specifically, we study non-negative solutions to

S
k

[

D
2

u
]
≥
h
(
u
,

|

D
u

|

)

S_k[D^2u]\ge h(u,|Du|)

in

R

n

\mathbb {R}^n

. The results depend on some qualified growth conditions of

h
h

at infinity. A Liouville-type result to subsolutions of a prototype equation
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper S Subscript k Baseline left-bracket upper D squared u right-bracket equals f left-parenthesis u right-parenthesis plus g left-parenthesis u right-parenthesis pi left-parenthesis StartAbsoluteValue upper D u EndAbsoluteValue right-parenthesis">

S
k

[

D
2

u
]
=
f
(
u
)
+
g
(
u
)
ϖ
(

|

D
u

|

)

S_k[D^2u]=f(u)+g(u)\varpi (|Du|)

is investigated. A necessary and sufficient condition for the existence of a non-trivial non-negative entire solution to

S
k

[

D
2

u
]
=
f
(
u
)
+
g
(
u
)

|

D
u

|

q

S_k[D^2u]=f(u)+g(u)|Du|^q

for

0
≤
q
>
k
+
1

0\le q>k+1

is also given.