Comparative Analysis of Facade Work Using Kumkang Precast, Concrete Precast, and Curtain Wall Methods in terms of Cost and Time

The development of the construction world in terms of innovation has become one of the methods of supporting success to gain advantages in terms of cost and time, one of which is the outer wall which can generally categorize into cast-in-situ and precast methods. (1) Comparison of the cost of implementing precast kumkang materials, precast concrete facades, and curtain wall facades. The precast kumkang method is 24% cheaper than the precast concrete method, the precast kumkang method is 87% cheaper than the curtain wall method, and the precast concrete method is 52% cheaper than the curtain wall method. Sorted from the cheapest to the most expensive are precast kumkang facades, precast concrete facades, and curtain wall facades. (2) Comparison of the working time of precast kumkang materials, precast concrete facades, and curtain wall facades with the results, namely curtain wall facades for 31 weeks, kumkang material precast facades for 53 weeks, and precast concrete facades for 55 weeks. Sorted from the fastest to longest, namely curtain wall facades, precast kumkang material facades, and then precast concrete facades.

Performance of a Nozzle to Control Bath Level Oscillations and Turbulence of the Metal-Flux Interface in Slab Molds

The characterization of the turbulent flow of liquid steel in a slab mold using a commercial nozzle was carried out through physical experiments and mathematical models. Six ultrasonic sensors were located at each side of the nozzle to obtain real-time plotting of the bath levels during the experimental time. An ultrasonic transducer located in the mold, 20 mm below the meniscus, determines the velocities and the turbulent variables along with the distance from the narrow face to the position of the nozzle’s outer wall. These data, together with the mathematical simulations, demonstrated a high correlation of bath level oscillations and the time-dependent behavior of the discharging jets. The flow inside the mold shows low-frequency non-symmetric patterns without a severe turbulent in the meniscus. The source of this instability is the partial opening of the slide valve gate used to control the mass flow of liquid.

Discussion on the Improvement of Technical Safety Scheme Compilation for Hazardous and Ultrahazardous Projects

This paper reviews the summary and analysis of special technical safety schemes for hazardous and ultrahazardous activities, supported by housing scaffolding, installation, and dismantling of outer wall attached tower crane, deep foundation pit with supporting structure, municipal bridge box girder formwork support, as well as grooved Larsen steel sheet pile, which are commonly seen in recent years, so as to enhance the pertinence, rationality, and economy of the special program to strengthen safety.

Active earth pressure against flexible retaining wall for finite soils under the drum deformation mode

A reasonable method is proposed to calculate the active earth pressure of finite soils based on the drum deformation mode of the flexible retaining wall close to the basement’s outer wall. The flexible retaining wall with cohesionless sand is studied, and the ultimate failure angle of finite soils close to the basement’s outer wall is obtained using the Coulomb theory. Soil arch theory is led to get the earth pressure coefficient in the subarea using the trace line of minor principal stress of circular arc after stress deflection. The soil layers at the top and bottom part of the retaining wall are restrained when the drum deformation occurs, and the soil layers are in a non-limit state. The linear relationship between the wall movement’s magnitude and the mobilization of the internal friction angle and the wall friction anger is presented. The level layer analysis method is modified to propose the resultant force of active earth pressure, the action point’s height, and the pressure distribution. Model tests are carried out to emulate the process of drum deformation and soil rupture with limited width. Through image analysis, it is found that the failure angle of soil within the limited width is larger than that of infinite soil. With the increase of the aspect ratio, the failure angle gradually reduces and tends to be constant. Compared with the test results, it is shown that the horizontal earth pressure reduces with the reduction of the aspect ratio within critical width, and the resultant force decreases with the increase of the limit state region under the same ratio. The middle part of the distribution curve is concave. The active earth pressure strength decreases less than Coulomb’s value, the upper and lower soil layers are in the non-limit state, and the active earth pressure strength is more than Coulomb’s value.

Effect of Strain Rate Sensitivity on Fracture of Laminated Rings under Dynamic Compressive Loading

The effects of cladding layers of rate-sensitive materials on the ductility and fracture strain of compressed rings are numerically investigated by using the finite element method (FEM) and employing the Johnson–Cook (J–C) model. The results show that ductility is governed by the behavior of the material that is located at the ring outer wall regardless of the volume fraction of the core and clad materials. However, as the number of layers increases, this influence becomes less noticeable. Moreover, as barreling increases at the outer wall and decreases at the inner wall, fracture strain increases. Furthermore, the effects of ring shape factor and bonding type of clad and core materials are numerically evaluated. The numerical results show that less force per unit volume is required to fracture narrower rings and that using a noise diffusion pattern at the interface of the materials is more suitable to simulate crack propagation in the compressed rings and functionally graded materials (FGMs). Additionally, delamination has a direct relation to layer thickness and can occur even in the presence of perfect bonding conditions owing to differences among the material and fracture parameters of laminated layers.

Engineering Method for Calculating the Temperature on the Inner Surface of the Outer Corner of a Building

Постановка задачи. Температура на внутренней поверхности наружного угла всегда меньше, чем по глади наружной стены, что при низких температурах наружного воздуха может приводить к образованию конденсата на внутренней поверхности стены. В связи с этим актуальным является проблема разработки инженерного метода расчета температуры в наружном углу для исключения возможности конденсатообразования на внутренней поверхности угла на стадии проектирования стеновых конструкций. Результаты. Для решения этой задачи на основе решения уравнения теплового баланса, учета амплитуды колебания температуры воздуха в помещении и теплопоглощения внутренних поверхностей стен, междуэтажных перекрытий (поверхности потолка и пола), перегородок, окон получена формула для вычисления температуры на внутренней поверхности наружного угла. Также в ходе исследования проведены натурные испытания стеновой конструкции с наружным углом и получены значения температур на внутренней и наружной поверхностях. Выводы. Сопоставление результатов расчетов по разработанной методике и экспериментальных данных показало, что значения температур на внутренней поверхности наружного угла практически совпадают. Это дает основание использовать предложенный инженерный метод расчета температуры на внутренней поверхности угла наружной стены при проектировании ограждающих конструкций зданий для создания благоприятных комфортных и санитарно-гигиенических условий в помещении. Statement of the problem. The temperature on the inner surface of the outer corner is always lower than on the inner surface of the outer wall. This temperature difference might lead to the formation of condensation on the inner surface of the wall at low outdoor temperatures. Therefore the problem of developing an engineering method for calculating the temperature in the outer corner to exclude the possibility of condensation on the inner surface in the design process of the outer wall structures is extremely relevant. Results. To address this problem, based on solving the heat balance equation, taking into account the amplitude of air temperature fluctuations in the room and heat absorption of the inner surfaces of walls, intermediate bottoms (ceiling and floor surfaces), parting walls, a formula was obtained to calculate the temperature on the inner surface of the outer corner. Also, through the course of the study, natural tests of the wall structure with an outer corner were carried out and the temperatures on the inner and outer surfaces were obtained. Conclusions. Comparison of the calculation results using the developed engineering calculation method and experimental data showed that the temperatures on the inner surface of the outer corner almost coincided. This makes it possible to use the suggested engineering method for calculating the temperature on the inner surface of the outer wall corner in the design of enclosing structures to exclude condensation.

Vortex evolution in a rotating tank with an off-axis drain

Fluid entering the periphery of a steadily rotating cylindrical tank exits through an off-axis drain hole, located in the tank's base at the half-radius. Experiments show that, though a concentrated vortex forms over the drain, it soon advects around the tank in what is at first a circular path. Though inviscid vortex dynamics predicts continued motion, our experiments show that the vortex moves inwards from the predicted circular path, finally coming to rest at approximately $50^{\circ }$ from the drain. In this final state, the vorticity is concentrated in a thin shear layer bounding an irrotational core, which passes over the drain. The broadening of the vortex structure and eventual steady-state formation are believed to be due to the growing boundary layer on the outer wall.

The Effect of Catalyst Placement on the Stability of a U-Bend Catalytic Heat-Recirculating Micro-Combustor: A Numerical Investigation

This study investigates the combined effect of catalyst placement and solid thermal conductivity on the stability of a U-bend catalytic heat-recirculating micro-combustor. The CFD code ANSYS Fluent 2020 R1 was used for two-dimensional simulations of lean premixed propane/air combustion by varying the inlet gas velocity, i.e., the input power. Three configurations were compared at low (3 W/(m K)) and high (30 W/(m K)) wall thermal conductivity: (A) the configuration in which both inner and outer walls are catalyst coated; (B) only the inner wall is catalyst coated; and (C) only the outer wall is catalyst coated. Numerical results show that, at low thermal conductivity, configuration (B) exhibits the same resistance to extinction as configuration (A), whereas at high thermal conductivity, configurations (B) and (C) exhibit much lower resistance to blowout than configuration (A). Accordingly, for low-power systems, which typically lose stability via extinction and thus require low-conductive materials, an optimal catalyst placement can be the partial coating of configuration (B). Conversely, for high-power systems, which are prone to blowout and thus require high-conductivity materials, a full coating of both the inner and outer walls is needed to guarantee higher stability. To elucidate these findings, a detailed analysis of the combustion behavior of the three configurations is presented.

A Review on Otitis externa: An Approach to a Etiopathogenesis, Epidemiology, Clinical Features and Management Protocol

Introduction: The external ear is the part of our ears which is seen from outside. It is made up of the auricles (pinna) and external auditory canal; and, includes the outer wall of the middle ear, i.e. the eardrum. Otitis externa is a regular presentation when on call for ENT or at the emergency ENT health clinic or centre. Infective and reaction groups of otitis externa are classified. Methodology: The articles reviewed in this narrative review article have been traced from a variety of links and sources over the internet like PubMed, NCBI, ScienceDirect, NHSINFORM, Uptodate, WebmedCentral, American family physician, ClevelandClinic, StatPearls, and many more. References from high yielding sources were taken and the articles were properly assessed. Results: Paying attention to the scientific elements while performing an operative procedure can give a physician extended results. Which operative modality to be chosen depends on the patient. The patient’s choices are also important in the decision making of the operation. Discussion: External otitis is possibly spotted in almost every peer category. Approximately ten percent (10%) of humans may face this condition during their lifetime. Most of the time, the infection is mixed. Medical intervention of the ear can prove painful for most cases, therefore, post-surgery analgesics must be utilized for a time period which the treating physician prescribes. The aim of curing the patient is to free him/her from the symptoms and getting rid-off any pathogen causing a specific infection. Conclusion: The efficacy of operative modalities of extremes of otitis externa will rely on complete patient examination, history and lab results. Selection of the correct intervention, proper knowlege of the regional anatomy, paying attention to scientific elements and good post-operative care is necessary. It is never easy to avoid otitis externa, but we can make an effort to decrease the risk of developing this problem.