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Biomass gasification is an established and widely utilized renewable energy system. The research work aims to develop and construct a downdraft gasifier to investigate gasifier performance. The gasifier’s performance and cold gas efficiency were calculated for three volumetric airflow rates: 7.16 m3/h, 5.97 m3/h, and 4.78 m3/h. The efficiency was found maximum of 69.6% for an airflow rate of 7.16 m3/h. The oxidation zone and neck region of the gasifier reactor had the maximum recorded temperatures of 845 °C and 823 °C for Swietenia macrophylla (SM) and Mangifera indica (MI), respectively. A two-dimensional computational fluid dynamics (CFD) model for a downdraft gasifier was also developed using ANSYS/FLUENT software. The simulation results provided valuable insights into thermal characteristics and the gasification process taking place inside the gasifier. Taking into account the introduction of wood at a rate of 6.2 kg/h and the flow of air at a rate of 7.16 m3/h, predictions were made about the composition of syngas, and subsequently, validation of the model was conducted with experimental data. The simulation study visually represents the gasification process, illustrating the distribution of velocity and the contours of carbon monoxide, carbon dioxide, and hydrogen within the gasifier. [ABSTRACT FROM AUTHOR]

Within the last decade, a construction‐friendly design principle using flexible wire ropes instead of traditional u‐bars for connecting wall elements has gained popularity. However, anchoring wire ropes in T and L connections remains a complex challenge. Here, the wire ropes stick out of the side of the wall element and are bent in the anchorage zone. This paper presents the findings of an extensive experimental program with 40 specimens, investigating the anchorage capacity of wire ropes in wall elements under these conditions. The study reveals that specially designed reinforcements significantly increase the anchorage capacity, while traditional wall reinforcements have minimal impact. Failure mechanisms primarily involve concrete cone failures, providing valuable insights for construction‐friendly connections. Based on the observed failure mechanism, the paper presents an analytical failure mechanism. The model is based on the upper‐bound theorem of plasticity theory. The model predicts both the capacity and the failure mechanism with satisfactory accuracy. [ABSTRACT FROM AUTHOR]

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Direct-fired supercritical CO2 (sCO2) power cycles are a pathway to low-CO2 fossil energy but contain O2 and H2O in the sCO2 from combustion. The effect of impurities on structural steels was investigated at 450°-650 °C in 30 MPa sCO2. The test matrix included 9 and 12%Cr ferritic-martensitic (FM) steels and conventional and advanced austenitic steels exposed for 1000-2000 h with and without additions of 1%O2 and 0.1%H2O to simulate the cycle after water removal. For FM steels, the mass gains and scale thicknesses were similar with and without impurities with the formation of thick, duplex Fe-rich scales in all cases including the observation that Fe2O3 only formed with 1%O2. For the austenitic steels, higher mass gains were observed at all temperatures with increased formation of Fe-rich oxides when impurities were added. Carbon ingress was assessed by bulk combustion analysis, glow discharge optical emission spectroscopy (GDOES) and measuring postexposure room temperature tensile properties. Bulk C content was strongly increased at 650 °C but not at 450° or 550 °C. [ABSTRACT FROM AUTHOR]

In today's rapidly developing infrastructure sector, which includes the construction of mega structures such as express highways, railways, tunnels, bridges, and tall buildings worldwide, finding suitable ground for these civil engineering projects poses a significant challenge for geotechnical engineers. Fortunately, several ground improvement techniques exist to strengthen weak and soft soils, tailored to the specific requirements of each application. In recent times, the use of Fiber-Reinforced Polymer (FRP) materials has gained popularity due to their multifunctionality, particularly in reinforcing concrete sections. This research delves into innovative approaches by employing FRP bars to enhance the bearing capacity and stiffness of soft clay soils. Specifically, two different polymer materials are investigated: uniaxial geogrid (an elastic–plastic material) and FRP (an elastic material). These materials aim to improve the bearing capacity of soft soil and enhance stability under loaded square footings. To explore their effectiveness, a model test was conducted using a square footing resting on soft clay. The study examined the impact of embedded FRB layers on controlling soft clay settlement and enhancing shear strength. The experimental model results were compared with analytical solutions obtained using the finite element program ABAQUS, revealing good agreement between computed and measured data. Further understanding of FRP—soil interaction outside the calibrated model is required to bridge the gap of the knowledge. Accordingly, a set of parametric studies were carried out using the calibrated numerical model. These studies investigated various parameters affecting the interaction mechanism between the soil and geogrid or FRP. Comparing reinforced and unreinforced cases, it was evident that using FRB is more effective than geogrid in improving the soft clay properties particularly in terms of settlement reduction and increased bearing capacity. Employing the FRP as reinforcement material significantly reduces soft clay settlement by approximately 48% while increasing its bearing capacity by about 93%. However, employing the geogrid reduces the settlement by about 30% of that developed unreinforced soil, while the bearing capacity of original soil increases by about 50%. Also, the efficiency of FRB layers is clear by adopting it at depth not less than 2.2B where, the first FRP net located at distance U = 0.7B under the footing. Also, the length FRB should be not less than 2B to be effective in reducing the consolidation settlement of the soft clay. Moreover, utilizing sand replacement with FRP layers proves effective in further reducing settlement and improving of bearing capacity of soft clay by about 90% and 130% respectively of that calculated in the unreinforced case. [ABSTRACT FROM AUTHOR]

Abstract The current work discusses the radiation attenuation capability and different shielding characteristics of different mortar samples. The samples were prepared by replacing different percentages of fine aggregate with iron filling and replacing different percentages of hydrated lime with Bi2O3 (0–50 wt.%). The prepared mortar samples are coded as CHBFX where X = 0, 10, 30, and 50 wt.%. The mass and linear attenuation coefficient was determined experimentally using a narrow beam technique, where a high purity germanium detector, and different point gamma-ray sources (such as Am-241, Cs-137, and Co-60). The linear attenuation coefficient was also calculated using the Monte-Carlo simulation code and the online Phy-X/PSD software. The comparison of the three methods showed a good agreement in the results. The linear attenuation coefficient drops from 19.821 to 0.053 cm−1 for CHBF0, from 27.496 to 0.057 cm−1 for CHBF10, from 42.351 to 0.064 cm−1 for CHBF30, and from 55.068 to 0.071 cm−1 for CHBF50 at photon energy range from 0.015 to 15 MeV. The half-value layer thickness, tenth-value layer thickness, and mean free path of the prepared mortar composites were also calculated photon energy ranged from 0.015 to 15 MeV. The fast neutron removal cross-section of the prepared CHBFX mortar samples have values of 0.096 cm−1, 0.098 cm−1, 0.103 cm−1, and 0.107 cm−1 for the mortar samples CHBF0, CHBF10, CHBF30, and CHBF50, respectively. The results showed that the mortar sample with the highest iron filing concentration, CHBF50, provides the best protection against gamma rays and fast neutrons which could be used in the nuclear and medical fields.

This study investigates the numerical modeling of a high-velocity circular free-water jet impinging into a plunge pool, focusing on the simulation and validation of mean and fluctuating dynamic pressures on the pool floor. Numerical simulations were performed using two different computation methods, two-phase volume-of-fluid and Euler–Euler, under conditions replicating experimental data obtained at a jet velocity of 7.4 m/s and plunge pool depth of 0.8 m. The models, based respectively on the Volume of Fluid (VoF) and Euler–Euler methods, were evaluated for accuracy in replicating experimentally measured pressures and air concentration values. The Euler–Euler solver, coupled with the k-Omega SST turbulence model, demonstrated mesh independence for mean dynamic pressures with a mesh resolution of 24 cells across the jet diameter. In contrast, two-phase volume-of-fluid exhibited mesh dependency, particularly near the jet stagnation point and pressure values higher than the experimental ones. While the Euler–Euler accurately captured mean pressures and air concentration in close agreement with experimental data, its Reynolds-Averaged Navier–Stokes (RANS) formulation limited its ability to simulate pressure fluctuations directly. To approximate these fluctuations, turbulent kinetic energy values were used to derive empirical estimates, yielding results consistent with experimental measurements. This study demonstrates the efficacy of the Euler–Euler method with the k-Omega SST model in accurately capturing key dynamic pressures and air entrainment in plunge pools while highlighting opportunities for future work on pressure fluctuation modeling across a broader range of jet conditions.

Geothermal energy exploitation has emerged as a critical solution to combat global climate crises, such as reducing CO2 emissions and climate warming. Scaling is the process of mineral precipitation in fluid pathways and geothermal equipment. It is known to significantly hamper geothermal energy production by decreasing the rates of heat extraction. Numerous research efforts are dedicated to characterising dissolution and precipitation processes, not only to provide know-how for further and safer developments in geothermal energy, but also to adapt such findings to the ever emerging field of geothermal energy recovery. This paper presents an overview of experiments—performed under variable pressure and temperature conditions—with a focus on scaling. We assess the different factors that influence disequilibrium reactions in carbonate rocks, the different experimental setups, and their application to the field. The influence of experimental variables (such as temperature and pressure) on mineral dissolution and precipitation is discussed, and the main learning points from experiments are compared and contrasted. We address techniques for preventing and controlling scaling in geothermal wells based on a comprehensive analysis of experimental studies in carbonate rocks. We propose that the intelligent combination of fieldwork, numerical approaches, and laboratory experience provides a foundation for the success of future work in this field.

German has two demonstrative pronoun series: the short form der, die, das, and the long form dieser, diese, dieses. Both forms can be used anaphorically, and they contrast with the personal pronouns er, sie, es in that they refer to an antecedent that is less prominent at that point in the discourse when the discourse provides different potential antecedents. Demonstrative pronouns are typically used in the preverbal position in a German sentence, i.e., the topic position. Thus, they are assumed to be topic shifters (from a non-topical antecedent to the topical argument in the current sentence). However, der can be repeated, yielding topic chains, thus referring back to a topical antecedent, while this is not the case for dieser. In this article, we argue that der and dieser both contribute to topic management, but they do this in different ways: der is a marker of a sentence topic, while dieser is a marker of discourse topic shift. We present the results of two experiments that compare the use of personal pronouns with either demonstrative pronoun manipulating sentence topic or discourse topic. First, both experiments show that the personal pronoun is not sensitive to either type of topichood of its antecedent. Second, Experiment 1 shows that both demonstrative pronouns prefer a context where discourse topic and sentence topic are shifted. Third, Experiment 2 shows that only dieser prefers a context with a shifted discourse topic, but der is not sensitive to discourse topichood alone. We take the results as supporting our claim that the two demonstratives have different discourse functions: der marks a sentence topic, while dieser is a shifter (and marker) of the discourse topic. [ABSTRACT FROM AUTHOR]

When fire exposes the hybrid reinforced concrete R.C. columns, it seriously damages the mechanical qualities of steel bars, concrete, and glass fiber reinforced polymer G.F.R.P. bars. This study focused on hybrid reinforced concrete R.C. columns’ behaviour and failure modes that were eccentrically and concentrically loaded during the fire until a failure. The behaviour of these R.C. columns will be quantified by demonstrating and going over the load-displacement relationships, failure mechanisms, crack patterns, strain distribution at failure, ductility, and stiffness. The number and width of cracks in the columns heated to 300 ºC, 500 ºC, and 700 ºC were significantly more than in the unheated columns. When the specimen is exposed to high temperatures, less force is needed to cause a first crack, and the ultimate strength decreases as the applied load and eccentricity ratio values increase. Hence, all specimens’ axial and lateral displacement values increase. This can be explained by two factors: the depth of the practical section because of the thermal expansion effect and the cracking expansion of concrete when subjected to high temperatures, and heating causes a loss in stiffness of column because the elasticity of concrete’s modulus of elasticity drops. [ABSTRACT FROM AUTHOR]

A weir is a structure consisting of an obstruction such as a dam that built across the open channel to change its flow characteristics. In the present study, a total 12 experiments were done in the laboratory of civil engineering department inside an open channel with 20 cm width and installing full width rectangular sharp crested weirs. Then the numerical runs were validated with experimental findings and additional runs were done. The implementation of Numerical Methods A volume of fluid (VOF) model was created for the situation when water and air are in direct contact with one another. Three distinct k-epsilon turbulence models were examined [standard, RNG, and realizable]. According to mass balance data, the greatest error in experimental measurements between the main channel's input and outlet discharges does not exceed 9.542%. Furthermore, average percentage of error between numerical and experimental outlet discharges for standard, RNG and realizable k-epsilon method was 7.235, 5.489 and 7.301 respectively. Cd increased with increasing the ratio of (H1/P). The water surface will be stable along 2 m of upstream channel length upstream of the sharp crested weir, and the longitudinal water levels will decrease slightly over the weir with a curved profile, as determined experimentally and numerically. [ABSTRACT FROM AUTHOR]

The current work discusses the radiation attenuation capability and different shielding characteristics of different mortar samples. The samples were prepared by replacing different percentages of fine aggregate with iron filling and replacing different percentages of hydrated lime with Bi2O3 (0–50 wt.%). The prepared mortar samples are coded as CHBFX where X = 0, 10, 30, and 50 wt.%. The mass and linear attenuation coefficient was determined experimentally using a narrow beam technique, where a high purity germanium detector, and different point gamma-ray sources (such as Am-241, Cs-137, and Co-60). The linear attenuation coefficient was also calculated using the Monte-Carlo simulation code and the online Phy-X/PSD software. The comparison of the three methods showed a good agreement in the results. The linear attenuation coefficient drops from 19.821 to 0.053 cm−1 for CHBF0, from 27.496 to 0.057 cm−1 for CHBF10, from 42.351 to 0.064 cm−1 for CHBF30, and from 55.068 to 0.071 cm−1 for CHBF50 at photon energy range from 0.015 to 15 MeV. The half-value layer thickness, tenth-value layer thickness, and mean free path of the prepared mortar composites were also calculated photon energy ranged from 0.015 to 15 MeV. The fast neutron removal cross-section of the prepared CHBFX mortar samples have values of 0.096 cm−1, 0.098 cm−1, 0.103 cm−1, and 0.107 cm−1 for the mortar samples CHBF0, CHBF10, CHBF30, and CHBF50, respectively. The results showed that the mortar sample with the highest iron filing concentration, CHBF50, provides the best protection against gamma rays and fast neutrons which could be used in the nuclear and medical fields. [ABSTRACT FROM AUTHOR]

Various industrial applications, including rotating and reciprocating machinery, depend on gears. Therefore, a sudden breakdown of the gears could result in substantial financial losses. Due to this, extensive studies have focused on defect diagnosis. Both machinery maintenance decisions and preventive maintenance techniques have been aided by vibration analysis. An increased vibration is a warning sign that a machine is about to malfunction or break down. Observing and evaluating the machine's vibration pulses can identify the nature and extent of the issue and, as a result, predict when the machine will fail. The vibration signal may identify gearbox defects early on and diagnose its problems. Hence, this research highlights the main crucial steps that can be followed for defect detection and identification, mainly based on vibration analysis methodologies. It provides an application methodology for various signal-processing techniques used successfully in rotating machinery. The study briefly explains the applied methods to diagnose problems that depend on hybrid artificial intelligence approaches, such as fuzzy sets, expert systems, and neural networks. The key aspect of the present paper is the parametric comparison of the performance of various artificial Intelligence systems used in rotary machines. As such, the paper reports a comprehensive study of the gearbox defect diagnosis and provides useful analysis, which would be helpful for the usage of such techniques in the engineering industry.

In modern society, the family is an important component of universal culture that preserves traditional national values. In the conditions of ongoing social changes leading to the growth of national self-consciousness, return to the roots, destruction of stereotypes, change of attitude to family values, it is necessary to preserve the understanding of the family as a traditional social institution. In this regard, the study of proverbs and sayings reflecting universal and national family values is of great importance. The aim of the study is to identify and substantiate family values in the upbringing of the younger generation in modern Chuvash families. The article considers traditional family values as the foundation of a strong and friendly family. The analysis of Chuvash proverbs and sayings about family life and family relations in the article shows that the Chuvash people place family values highly, brought up on national cultures and traditions. Our practical research shows that children's attachment to their parents is increasingly weakening. The lack of understanding of their children's behavior is explained by the following reasons: 1) parents' lack of fundamental pedagogical knowledge and skills; 2) parents' neglecting the basics of Chuvash family upbringing based on spiritual and moral values in the upbringing of their children. The author argues that the study of the basics of ethnic pedagogy will give positive results in the upbringing of children. The article used both general theoretical methods, including both the analysis of psychological and pedagogical literature on the topic under consideration, including encyclopedic and reference literature, folklore works, and empirical methods, including pedagogical observation, the use of questionnaires and surveys, and generalisation of ethnopedagogical experience. The experimental work was carried out to determine the moral potential of traditional family values in the Chuvash family. The author comes to the conclusion that Chuvash families have preserved national customs and traditions that they inherited from their ancestors in order to pass on to the next generations as a common reference point in their family life.

Developing mega structures like highways and railways, bridges, and tall buildings constructed over soft clay becomes challenging for geotechnical engineers. Soft clays are considered problematic soils as they possess high compressibility and low shear strength. There are several methods for improving in situ conditions of soft clays. This research focuses on using geogrid to improve soft soil and increase its stability under loaded square footing. A model test was developed in this study for square footing resting on soft clay to investigate the effect of uniaxial geogrid to control the soil settlement and enhance its shear strength. The results of the experimental model were compared with the analytical solution using the finite element program ABAQUS, where a good agreement was found between the computed and measured data. The second objective of the research was to focus on the parameters that increase the bearing capacity of soil and hence reduce the settlement other than the parameters used in the verification case. This was achieved by conducting parametric studies using the developed numerical model. The Parametric studies focus on the role of different parameters that affect the interaction mechanism between the soil and geogrid. These parameters included the number of geogrid layers, the first geogrid location, and the geogrid length. Also, the impact of creep settlement of reinforced soft clay was considered. It was found that placing geogrid layers at depth not less than 1.3B where, the first geogrid located at distance U = 0.7 under the footing is more appropriate for improving soft clay properties. Also, the length of geogrid should be not less than 3B to be effective in reducing the consolidation settlement of the soft clay. Moreover, the geogrid layers are ineffective in reducing the settlement resulting from creep.

German has two demonstrative pronoun series: the short form der, die, das, and the long form dieser, diese, dieses. Both forms can be used anaphorically, and they contrast with the personal pronouns er, sie, es in that they refer to an antecedent that is less prominent at that point in the discourse when the discourse provides different potential antecedents. Demonstrative pronouns are typically used in the preverbal position in a German sentence, i.e., the topic position. Thus, they are assumed to be topic shifters (from a non-topical antecedent to the topical argument in the current sentence). However, der can be repeated, yielding topic chains, thus referring back to a topical antecedent, while this is not the case for dieser. In this article, we argue that der and dieser both contribute to topic management, but they do this in different ways: der is a marker of a sentence topic, while dieser is a marker of discourse topic shift. We present the results of two experiments that compare the use of personal pronouns with either demonstrative pronoun manipulating sentence topic or discourse topic. First, both experiments show that the personal pronoun is not sensitive to either type of topichood of its antecedent. Second, Experiment 1 shows that both demonstrative pronouns prefer a context where discourse topic and sentence topic are shifted. Third, Experiment 2 shows that only dieser prefers a context with a shifted discourse topic, but der is not sensitive to discourse topichood alone. We take the results as supporting our claim that the two demonstratives have different discourse functions: der marks a sentence topic, while dieser is a shifter (and marker) of the discourse topic.

The article introduces the results, descriptions and analysis of the experiment on the reconstruction of the molding mass and the manufacture of ceramic vessels of the Chirik-Rabat culture (3rd–2nd centuries BC). The site adjacent to the pottery workshops of the Babish-mola 7 archaeological complex (Eastern Aral Sea region) was used as a landfill. There is the Akkyr hill nearby, abounding in reserves of clay raw materials. The experiment was conducted during the field research of the Chirik-Rabat archaeological expedition of the Margulan Institute of Archaeology in 2022. The main objective of this experiment was to determine all aspects of the production cycle for the manufacture of ceramic vessels – from collecting raw materials for the manufacture of ceramics, designing vessels, firing and ending with obtaining the result. During the experimental work, a search was carried out for clay deposits near the Babish-mola oasis along the riverbeds. The process of collecting organic matter (cattle manure) was carried out in the nearest settlement, located 60 km from the Babish-mola monument, for the admixture of chamotte, featureless fragments of ceramics from the monument were used. The vessels were formed on a single-disc turntable.

The friction clutch design strongly depends upon the frictional heat generated between contact surfaces during slipping at the beginning of the engagement. Firstly, the frictional heat generated reduces the performance of the clutch system and then leads to premature failure for contacting surfaces in some cases. The experimental effort in this work included manufacturing friction facing from functionally graded material (FGM) (aluminum and silicon carbide) for the clutch system. For this purpose, a special test rig was developed to investigate the thermal behavior of FGM and compare it with other frictional materials. The Taguchi L9 orthogonal design was selected to analyze the effect of the three factors (rotational, speed, torque, and the type of the frictional material) with three levels on the surface temperature of the contacting surfaces. A three-dimensional finite element model was built to validate the experimental results where the difference between them did not exceed 5.2%. The experimental results showed that the temperatures grew with the disc radius. Furthermore, the surfaces of the pressure plates and the flywheel were affected by frictional heat flow, and this effect increased when increasing the sliding speed. The lowest temperatures occurred when using FGM, which was lower than the other materials by 10%. This study presented an integrated approach consisting of design, manufacturing, and testing to study the complex frictional materials' effect on the clutch system's tribological performance. [ABSTRACT FROM AUTHOR]

Ethnoarchaeological research, which gained great popularity in the second half of the 20th century, has become a new full-fledged source for a variety of socio-economic reconstructions in archaeology, including when characterizing the features of industrial complexes. Developments that combine experimental traceological analysis of tools and ethnographic data play an important role in modeling ancient technologies, especially when ethnographic artifacts are a direct continuation of archaeological traditions, both in terms of their manufacturing method and specific purpose. In this regard, the study of stone knives from the Ekven burial ground of the 1st millennium AD is of great interest, discovered in Chukotka. These products have retained their specific form from antiquity to the present day. The presence in the archaeological and ethnographic collections of these items in varying degrees of processing and use (from blanks to tools with a completely recycled or redesigned working blade) made it possible not only to describe the chain of basic technological operations of their manufacture from the primary processing of raw materials, shaping, processing of the working and edge parts, mounts in the handle, but also to install the tools involved in this production process. The data obtained were verified using experimental work, which confirmed the invariability of the technology for processing slate raw materials and manufacturing archaeological and ethnographic man’s knives from it.

The gypseous soils present a challenge when utilizing them as a foundation for structures, making them a problematic soil type. However, when gypseous soils are saturated by anticipated sources such as acidic results from sewerage of industry, the minerals are soluble, resulting in the subsidence of the structures. The study aims to provide valuable insights into the behavior of gypseous soils, which are known for their tendency to collapse and settle. It considered the impact of acidity on the potential for the collapse of gypseous soils, a crucial area of research that can benefit multiple fields. To comprehend the mechanisms governing the behavior of acidic gypseous soils, an investigation in the lab is carried out to determine how the presence of acidity in varying concentrations affects the possibility of the collapse of gypsum soils. To examine the impact of acidity on the chemical composition of gypseous soils, a Scanning Electron Microscope (SEM) analysis was conducted. The results of the analysis were used to create a map of this effect. In addition, the effect of different parameters such as unit weight and initial water content of gypseous soils and their effect on the collapse potential is studied. The results indicate that gypsum dissolves due to a change in the chemical composition of the soil, resulting in an increase in the collapse potential of gypseous soils. Consequently, the concepts of gypsum soil treatment must take into consideration the nature of the facilities constructed on this type of soil, such as industrial structures. [ABSTRACT FROM AUTHOR]

The need for educational approaches that comply with the restrictions arising from the COVID-19 pandemic has raised a number of critical issues for students of different age groups. The delicate transition between high school and university has become a key point to focus on, leading many institutions to replan projects dedicated to students involved in this transition. A Physics vocational training project for high school students was carried out in the school year 2020–2021, and it was replicated in the school year 2021–2022. The project included webinars, self-assembled laboratory group experiences, and peer evaluation. The starting point on which we designed our project is that learning is an experience; thus, we built the entire project by particularly focusing on two peculiarities. One peculiarity is the assessment methods: student presentations describing their own experiences were evaluated by teachers and their peers. The second peculiarity is the open approach with respect to how students handle experimental activities. We present a description of these projects along with the results of an evaluation survey filled out by the participants and a descriptive analysis of the assessment strategies. Students appreciated the design of the entire project and, better still, the peer evaluation process. Moreover, we discovered that the evaluation provided by the teachers is lower compared to the assessment reported by the students. This disparity holds potential significance from a statistical perspective and warrants further investigation. [ABSTRACT FROM AUTHOR]

Concrete, a widely used construction material, exhibits inherent brittleness and limited tensile strength. To address these shortcomings, the incorporation of fibers has gained prominence, with polyolefin and polypropylene fibers emerging as promising reinforcements. This study experimentally conducted and examined the mechanical characteristics of polyolefin and polypropylene fibers-reinforced concrete. The study involved conducting compressive strength tests and durability tests, including sulfate resistance, acid resistance, chloride ion penetration resistance, and abrasion tests. The results demonstrated a notable enhancement in the compressive strength of both cubic and cylindrical specimens with varying dimensions, owing to the inclusion of polyolefin fibers. Polyolefin fibers exhibited a greater reinforcing effect compared to polypropylene fibers, especially in larger cubic specimens and cylindrical specimens. The quantitative results show that specimens with polypropylene fibers exhibited a 9.67 % improvement in compressive strength, while those with polyolefin fibers showed a 30.47 % enhancement compared to specimens without fibers. The acid resistance test revealed that both types of fiber-reinforced specimens exhibited higher compressive strength in acidic environments compared to plain concrete specimens. In the chloride ion penetration resistance test, the polyolefin fiber-reinforced specimen demonstrated the highest resistance to degradation, while the plain concrete specimen exhibited the lowest resistance. Polyolefin demonstrated superior reinforcement compared to polypropylene, with a 35 % increase in acid resistance and better chloride ion resistance. In contrast, specimens without fibers weakened by 35.36 % in a chloride environment. The sulfate resistance test showed that the polyolefin fiber-reinforced specimen had the highest compressive strength in a sulfate environment, while the plain concrete specimen had the lowest. In sulfate and abrasion tests, polyolefin-fiber-reinforced specimens displayed the highest resistance and the lowest abrasion rate of 34.6 %. These findings highlight the potential of polyolefin fiber-reinforced concrete for enhancing mechanical properties and durability in various applications.

Scour is a natural phenomenon caused by the removal of soil from bed caused by a stream's erosion, which happens around or next to moving water structures. Various studies have been conducted to understand better local scour events in order to construct hydraulic structures safely and economically. This paper investigated the use of a sill under the gate and its effect on the maximum scour depth downstream of a sluice gate. The experiments were performed at different relative sill heights (hs/Ls = without sill, 3.8, 8.0, 12.0, and 15.0%), and with various relative gate openings (a/Ls) of 13%, 18%, and 23%. The results revealed the effectiveness of the sill under the gate in decreasing the maximum scour depth. All sill heights reduced the maximum scour depth downstream of the sluice gate. The relative sill height of 8% gave the minimum value of the maximum relative scour depth for all relative gate openings. The results of this study can be used in the design considerations for gates and their protection. [ABSTRACT FROM AUTHOR]

In this study, a software has been developed for calculating static strength of bolted steel plates. This software has been developed by adding equations covering the bending moment that occurs during a tensile test as well as under real loading conditions. In order to test the accuracy of this program, 5 samples with the M6 bolt connection were prepared. In addition, the simulation result was compared with the experimental work performed with tensile tests and the finite element analysis made in Ansys. [ABSTRACT FROM AUTHOR]

In this study, the effects of the gate opening, sill placement with different widths under the gate, and the sill position from under the gate on the discharge coefficient were investigated experimentally. Sills are placed in positions below, tangentially and upstream of the gate at distances of 7.5 and 17.5 cm from the gate. The results of the present study showed that the discharge coefficient increases with increasing sill width and decreasing total area of the flow passing through the gate. The discharge coefficient increases by installing the sill at certain intervals at increasing distance with respect to the upstream of the sluice gate and has a lower value compared to the non-sill state. At the same opening in non-sill and suppressed sill states, with a sill below and tangential to the gate, the discharge coefficient of the sluice gate with the sill has increased compared to the non-sill state. In addition, the discharge coefficient for a tangential sill has the highest value. HIGHLIGHTS Experimental investigation of the sluice gate discharge coefficient without and with sills in different widths and positions has been done.; A general equation for calculating the flow rate passing through the sluice gate in suppressed sills was developed for non-suppressed sills.; This investigation improves the design of hydraulic control structures.;

There was a dearth of research into the behavior of eccentric RC columns reinforced with fibers, particularly recycled plastic fiber (RF) reinforced columns. The effect of employing end hooked steel fiber (EF) and RF on the performance of eccentric columns was explored in this experiment. Under compressive eccentric load, eight RC columns of 150 × 150 × 1000 mm with a 2% longitudinal reinforcement ratio were tested up to failure. The ratio of load eccentricity to column dimension was 15%. The fiber content (Vf) was variable. Both EF and RF had a Vf of 1%, 2%, and 3%. The applied load was recorded axial/lateral displacement and transverse/longitudinal reinforcement strain. The ultimate load (Pu), ultimate displacement, yield load, stiffness, and ductility index (∆) were all calculated to investigate column behavior. Results showed that adding fibers prevented the concrete cover separation hence prevented the sudden failure as it happened in the control column without fiber (P0). 1% RF and 2% EF enhanced Pu by 10.4% and 34.8%, respectively, while fiber content 3% decreased Pu. Stiffness of columns containing 1% RF and 2% EF was 16.3% and 33.8% higher than that of P0, respectively. The use of 1% and 2% EF delayed yield load, resulting in improved column performance. All fiber contents significantly improved ductility, with enhancement rates ranging from 4.2% with 3% RF to 146.2% with 3% EF. Also, use of 1% RF increased ductility by 70.6%. [ABSTRACT FROM AUTHOR]

Oral drug delivery is the Holy Grail in the field of drug delivery. However, poor bioavailability limits the oral intake of macromolecular drugs. Oral devices may overcome this limitation, but a knowledge gap exists on the device-tissue interaction. This study focuses on needle insertion into the human stomach experimentally and numerically. This will guide early stages of device development. Needle insertions were done into excised human gastric tissue with sharp and blunt needles at velocities of 0.0001 and 0.1 m/s. Parameters for constitutive models were determined from tensile visco-hyperelastic biomechanical tests. The computational setup modeled four different needle shape indentations at five velocities from 0.0001 to 5 m/s. From experiments, peak forces at 0.1 and 0.0001 m/s were 0.995 ± 0.296 N and 1.281 ± 0.670 N (blunt needle) and 0.325 ± 0.235 N and 0.362 ± 0.119 N (sharp needle). The needle geometry significantly influenced peak forces (p < 0.05). A Yeoh-Prony series combination was fitted to the tensile visco-hyperelastic biomechanical data and used for the numerical model with excellent fit (R2 = 0.973). Both needle geometry and insertion velocity influenced the stress contour and displacement magnitudes as well as energy curves. This study contributes to a better understanding of needle insertion into the stomach wall. The numerical model demonstrated agreement with experimental data providing a good approach to early device iterations. Findings in this study showed that insertion velocity and needle shape affect tissue mechanical outcomes. [Display omitted] • Experimental and numerical analysis of needle insertions into human stomach. • Comprehensive setup with different needle insertion velocities and needle geometries. • Numerical excellence in capturing needle-tissue behavior. • Simple numerical model is useful in early device iterations. • Insertion velocity and needle geometry significant affect tissue mechanical outcomes. [ABSTRACT FROM AUTHOR]

Featured Application: The study's findings have implications for the design of reinforced concrete structures, as they reveal new insights into the location and prediction of cracks in beams subjected to bending. Based on these findings, the authors recommend that design rules for predicting crack widths should be updated to incorporate the sag-to-free-span ratio as a key factor. As materials and structural optimization continue to be important in design, structural safety checks for service limit states have become increasingly important. One key aspect of these checks is the controlling of cracks to prevent them from affecting the structure's function or appearance. However, the authors have found that current regulations do not accurately reflect the reality of crack behavior. This is the case of the crack spacing. To address this issue, the authors conducted experiments on 27 reinforced concrete beams to investigate crack location, cracking moment, corresponding deflection, and crack width values as sag increases. Their main finding was that cracks tend to appear at the stirrup locations, and that crack width increases linearly with the sag-to-free-span ratio up to the yielding point. They also concluded that increasing the amount of tensile reinforcement is an effective way to reduce crack width for the same sag. [ABSTRACT FROM AUTHOR]

The friction clutch design strongly depends upon the frictional heat generated between contact surfaces during slipping at the beginning of the engagement. Firstly, the frictional heat generated reduces the performance of the clutch system and then leads to premature failure for contacting surfaces in some cases. The experimental effort in this work included manufacturing friction facing from functionally graded material (FGM) (aluminum and silicon carbide) for the clutch system. For this purpose, a special test rig was developed to investigate the thermal behavior of FGM and compare it with other frictional materials. The Taguchi L9 orthogonal design was selected to analyze the effect of the three factors (rotational, speed, torque, and the type of the frictional material) with three levels on the surface temperature of the contacting surfaces. A three-dimensional finite element model was built to validate the experimental results where the difference between them did not exceed 5.2%. The experimental results showed that the temperatures grew with the disc radius. Furthermore, the surfaces of the pressure plates and the flywheel were affected by frictional heat flow, and this effect increased when increasing the sliding speed. The lowest temperatures occurred when using FGM, which was lower than the other materials by 10%. This study presented an integrated approach consisting of design, manufacturing, and testing to study the complex frictional materials’ effect on the clutch system’s tribological performance.

In this research, an ejector was designed and manufactured from brass metal as part of a cooling system to cool agricultural products, work of ejector is based on the Venturi principle. The primary fluid is air and steam of product is the secondary fluid, used the primary pressure (1, 8, 1) bar for the purpose of conducting the experiment. The ejector was manufactured from a number of interconnected parts to give the final shape. The performance of the ejector was analyzed theoretically, through operating of system evaporation of water take place in vessel leads to cooling product at change operation condition and the examination, it was reached: a- The cooling efficiency of the product increases by increasing the primary pressure. b- The cooling efficiency of the product increases by decreasing the mass of the product. c- The loss weight of the product increases by increasing the primary pressure.

The need for educational approaches that comply with the restrictions arising from the COVID-19 pandemic has raised a number of critical issues for students of different age groups. The delicate transition between high school and university has become a key point to focus on, leading many institutions to replan projects dedicated to students involved in this transition. A Physics vocational training project for high school students was carried out in the school year 2020–2021, and it was replicated in the school year 2021–2022. The project included webinars, self-assembled laboratory group experiences, and peer evaluation. The starting point on which we designed our project is that learning is an experience; thus, we built the entire project by particularly focusing on two peculiarities. One peculiarity is the assessment methods: student presentations describing their own experiences were evaluated by teachers and their peers. The second peculiarity is the open approach with respect to how students handle experimental activities. We present a description of these projects along with the results of an evaluation survey filled out by the participants and a descriptive analysis of the assessment strategies. Students appreciated the design of the entire project and, better still, the peer evaluation process. Moreover, we discovered that the evaluation provided by the teachers is lower compared to the assessment reported by the students. This disparity holds potential significance from a statistical perspective and warrants further investigation.

Infilled frames are usually modelled in the context of global building analysis using simplified procedures without considering the aspects resulting from the interaction between the panel and the frame. Other aspects, such as adequate design of the floor beams and the beam-columns' joints, and control of potential sliding shear failure of the columns, that significantly affect the structural response, are also typically not accounted for. In the present work it is intended to look over the literature to evaluate the state of the art regarding the lessons learn from recent earthquakes, the evolution of the structural codes considering the infill masonry panels, and how this influences the evolution of the numerical models and the experimental works to overcome the existent gaps. [ABSTRACT FROM AUTHOR]

The thermal characteristics of four types of dry friction clutch materials (LUK, G95, HCC, and Tiger) are investigated experimentally and numerically in the present work under different working conditions; such as initial sliding angular velocity (ωro), torque (T), and sliding time (ts). The temperature distributions over a cross‐section of friction clutch elements (pressure plate and flywheel) are investigated and optimized during the sliding period (heating phase), and full engagement period (cooling phase). The effect of alternative frictional materials lining of a clutch disc on the thermal behavior of the sliding system under different operating conditions (different angular velocities, torques, and sliding periods) is investigated experimentally. The results showed that the maximum effect on the temperature values occurred when applying maximum torque (4.5 kg·m), maximum initial rotational speed (1200 rpm), slipping period (30 s). However, the temperature values at interface contact decrease when decreasing all the above input conditions values to (2.5 kg·m, 690 rpm, and slipping period to 8 s). The results showed that the temperature reduced (53%) from (180.4°C) for applied torque 4.5 kg·m with initial rotational speed (1200 rpm) and slip period (30 s) to (83.3°C) when applied torque 2.5 kg·m, initial rotational speed (680 rpm) and slip period (8 s) for clutch disc (LUK). It was obtained the same behavior for the other three discs (G95, HCC, and Tiger), but with different values of temperatures. The results show that the temperatures of the pressure plate interface (Tmax = 159.1°C) are higher than those at the flywheel interface (Tmax = 152.7°C), due to the low thermal capacity of pressure plate compared to the flywheel when using G95 frictional material. The experimental optimization results showed that the highest temperatures were obtained when using friction clutch disc (LUK), and minimum temperature when using (HCC) disc, around (20%) reduction when replaced (LUK) material with (HCC) under the same working conditions (T = 4.5 kg·m, ωro = 1200 rpm, and ts = 30 s). [ABSTRACT FROM AUTHOR]

Introduction: successful treatment in patients with significant bone defects secondary to infection, non-union and osteoporotic fractures resulting from previous trauma is challenging. In the current literature we did not find any reports that compare the use of intramedullary allograft boards versus the same ones placed lateral to the lesion. Material and methods: we worked on a sample of 20 rabbits (2 groups of 10 rabbits each). Group 1 underwent surgery using the extramedullary allograft placement technique, while group 2 with the intramedullary technique. Four months after surgery, imaging and histology studies were performed to compare between groups. Results: the analysis of the imaging studies showed a statistically significant difference between both groups with greater resorption and bone integration of the intramedullary placed allograft. Regarding histology, there were no statistically significant differences, but there was a significant prediction with a p value < 0.10 in favor of the intramedullary allograft. Conclusion: through our work we were able to show the great difference between the allograft placement technique with respect to imaging and histological analysis using revascularization markers. Although the intramedullary placed allograft shows us greater bone integration, the extramedullary graft will provide more support and structure in patients who require it. [ABSTRACT FROM AUTHOR]

The placement of buildings and structures on/or adjacent to slopes is possible, but this poses a danger to the structure due to failures that occur in slopes. Therefore, a solution or improvement should be determined for these issues of the collapse of the structure as a result of the failure of the slopes. A laboratory model has been built to test the impact of some variables on the bearing capacity factor. The variables include the magnitude of static axial load applied at the center of footing, the depth of embedment, the spacing between geogrid reinforcement layer and the numbering of the geogrid sheet under the footing, the inclination angle of slope clayey soil (ß), the spacing between the footing's edge and the slope's end (b/H). The results show that the critical case of reduction in bearing capacity is mobilized at (b/H< 0.25) and (β> 30°). A design chart has been obtained to the case of unreinforced slope soil under a footing to describe the reduction in (Nc) when increasing the inclination angle and another design chart of the case of reinforced slope soil with (N=1, 2 and 3) has been obtained to show the increase in value of (Nc) with increasing the number of the reinforced layer at different values of (ß) and finally simple equations have been obtained in order to calculate the ultimate bearing capacity of foundation on sloped clayey soil at different number of reinforcement. [ABSTRACT FROM AUTHOR]