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Several techniques based on ultrasound have been proposed for non-destructive evaluation (NDE). It has been widely applied in many fields such as medicine, mechanical, and construction, especially for the detection of cracks and flaws in structures and for the identification of material properties, which is capable of performing tasks to provide quick measurements while guaranteeing great accuracy. In this paper, we have developed the technique of ultrasonic transmission by water immersion as an alternative technique to study the propagation of ultrasonic waves in two structural materials: wood and wood protected by liquid paint (cement). Overall, the application of the transmission technique by change of the angle of incidence enables the demonstration of the experimental dispersion curves for the ultrasonic modes within the plates and allows the investigation and characterization of the function of the paint system (cement) in the wood plate.

The paper presents a mathematical model for calculating cutting forces during the machining of 16MnCr5 steel using the Sandvik CNMG 120408 16P25T tool. The modeling process involved the use of a test rig constructed based on the 16Д25 machine, which enabled the measurement of real values of spindle speed, longitudinal feed, cutting depth, and cutting forces. The results transmitted to a computer through the LTR-EU-8 workstation, equipped with galvanic isolated LTR modules and a synchronization interface. Based on the experimental results, the theoretical model demonstrated a deviation from actual measurements of no more than 4.72%. The study provides evidence that the cutting force calculations commonly presented by leading tool manufacturers are inherently overestimated. he difference in cutting forces can be 9%.

In the last twenty years, the manufacturing of titanium and its alloys for commercial use continued to expand. As this material has several very advantageous properties, leading to increasing applications in various industries, it is seldom used in mechanical engineering applications due to its tribological properties, which are unfavourable. The nitriding process is one of the most frequently used thermochemical processes designed to enhance the surface characteristics of titanium alloys and improve tribological properties. Various types of nitriding for titanium are studied, such as ion nitriding, plasma nitriding, laser nitriding and gas nitriding. This article provides a comprehensive examination of research papers on different advancements through a systematic literature review conducted in the period 2017-2023 about titanium nitriding for its process parameters, characteristics and functionalities of the product, particularly emphasising their contributions in surface characteristics and mechanical properties. The review seeks to offer an understanding of how the predominant processing factors, specifically temperature and time, affect the microstructure and the creation of novel phases. This review suggests a challenge for future researchers to investigate mechanisms of microstructure evolution and its impact on mechanical properties in conditioned environments to microhardness and ability to withstand rusting of titanium and its alloys.

A deep understanding on the intermixing of components in hybrid yarn or composite structures is decisive in order to develop hybrid structures with desired properties. This paper presents the development of a versatile procedure for the determination of the degree of fiber mixing in yarns and composites based on microscopy images auto-segmented by a neural network. The procedure is based on the quantification of blend irregularity values and blend homogeneity. For this purpose, functions of spatial point patterns analysis have been used to investigate the blend uniformity of yarn and composite cross sectional areas. The results show that the trained neural network model for segmentation of images has an accuracy of 92 %, indicating that the method is capable of accurately assessing the location of fibers in hybrid struc-tures. The results of the spatial point patterns analysis reveals a correlation between the blend value and the properties of yarns and composites. The proposed method provides a fast and reliable way to evaluate the hybrid structures, which could be used as a tool for quality control and process optimization.

Motion capture, especially of the knee angle, is an important component for situational triggering of functional electrical stimulation (FES). One major disadvantage of commercial FES devices is their bulky design that prevents unobtrusive wearing in everyday life and limits the patient’s free choice of appearance. This paper presents an alternative approach of sensors for motion capture in form of textile-based strain sensors. These can be integrated in a FES system in form of functional leggings, which make the FES system suitable for an unobtrusive daily use. Textile sensors, especially knitted sensors have already proven to be very promising to detect tensile strain. In particular, weft-knitted strain sensors, which can be integrated directly into the clothing during the knitting process, have the potential to detect the knee angle and therefore derive the gait phase due to the bending of the limbs without disturbing the wearer unnecessarily. Different designs of the weft-knitted strain sensor and their influence on the measurement behaviour of the sensor have been investigated. The weft-knitted strain sensor can be directly integrated in the knee area of the functional leggings to be used as a soft trigger to initiate electrical impulses for FES.

In the research field of smart textiles, one main goal concerns quantifying environmental forces acting on the wearer's body since textiles, acting as the boundary between the two, are an excellent way of integrating sensors. Integrating strain and pressure sensors into wearables promises a simple way of monitoring a person's posture and forces acting on their body. Sensors relying on a capacitive measuring principle are highly suitable for this, as they are less sensitive to changes in temperature than resistive or inductive types. In this paper, textile-based capacitive sensors are produced by braiding conductive yarns with and without an electrically insulating TPU sheath. The produced sensors are analyzed in cyclic strain and compression tests. Moreover, their behavior under changing temperatures is tested to prove their resilience against environmental changes. To extend their capabilities from an integral measurement to a localized assessment of the strain, time-domain-reflectometry (TDR) is employed. Finally, the sensors are integrated into a flexible actuated bending beam, and their adoption for soft robotics is discussed. Strain is tested cyclically, showing good long-term stability. Pressure sensitivity is measured in a static compression test under increasing force. TDR is used to localize strain in two discreet sections of the sensor. Although strain could not be quantified through TDR, characteristic points in the measured response signal indicating the position of the strain were identified. Textile-based capacitive sensors are suitable for strain up to 10 % and pressure up to 8 N. The determined gauge factors are satisfactory, with strain sensors inherently having a higher gauge factor than pressure sensors. Furthermore, they display good long-term stability and no adverse reaction to changes in temperature. TDR is proven to provide localization of strain in flexible sensors.

Current research focuses on advancements and breakthroughs in the realm of smart textiles, with applications spanning various industries such as medicine and education. For producing flexible smart textiles, electrically conductive yarns (EC) are needed to transmit signals or as part of sensor systems. Mostly, these EC consist of a polymer core with an outer metallized layer. Using EC in contact with skin requires high reliability and safety, and thus, the EC must maintain their functional properties on a long-term scale under a range of different stresses. The electrical properties of EC deteriorate under mechanical stress applied during production or in-use through damage to the yarn’s surface. At present, there are only partially feasible solutions to protect the metal-layer of the yarn surface. Hence, this paper presents a newly developed non-toxic coating (NTC) to protect the EC surface. The NTC consists of an aqueous emulsion with polypropylene wax and oxidized wax. To determine the long-term stability of the coating, the produced yarns undergo comprehensive evaluation using a range of analytical techniques. The aim is to identify the optimal coating by exploring different equipment and parameters. Additionally, it is various test methods to gauge the durability of the newly developed NTC used and ensure its reliability over time. To characterize the yarn properties before and after the coating, light microscopy (LM), washing processes, mechanical resistance tests and resistivity measurement are conducted.

Transition metal dichalcogenides (TMDCs) nanomaterials, in particular Molybdenum disulfide (MoS2), have been employed frequently as a basis for flexible gas sensors due to their extreme sensitivity to gas molecules, super mechanical and electrical properties, and large surface area. This work aims to study the behavior of the flexible gas sensor made of 2D-MoS2 under exposure to nitrogen dioxide (NO2) gas at the part per million (ppm) level. The mono-layered MoS2 was successfully synthesized by Chemical Vapor Deposition (CVD). The formation of MoS2 layers was confirmed by Raman spectroscopy and Photoluminescence (PL). Two different gas-sensing devices were fabricated by transferring two MoS2 samples (obtained from two positions inside the CVD tube) onto paper substrates. Specifically, upstream sample Sup was obtained from an area near the MoO3 source, and downstream sample Sdown was obtained from an area far from the MoO3 source. Both sensors showed a good response to a concentration as low as (1.5 ppm) of NO2. Although a high response of 62.8% along with a fast response of 9 sec were recorded by Sdown, the sensor showed a slow recovery time of 42 sec. On the other hand, Sup showed good stability with an appropriate response of 36.8% along with a reasonable response time and recovery times of 20 and 27 sec, respectively. Such behavior could be accredited to the difference in the reactivity in both MoS2 samples. This work opens the way for further improvements in manufacturing MoS2-based flexible gas sensors.

Micro EDM is unconventional metal removing technique that is effective in machining hard-to-cut conductive materials. It has a big potential in modifying surfaces of metallic bone implants for better biocompatibility by providing proper surface topography to ease cell adhesion. However, it is still important to study machining performance. This paper investigates material removal rate (MRR) and surface roughness (SR) of micro WEDM on Ti-6Al-4V alloy. Three level Taguchi’s design was implemented to observe the effect of capacitance and gap voltage. Moreover, analysis of variance (ANOVA) and grey relation analysis (GRA) allowed to investigate contribution of each parameter and find their best combination for multiple output optimization. Results showed that highest MRR of 1.72*10-2 mm3/s can be achieved at 10 nF and 90 V values, while smallest SR of 0.309 µm can be achieved at 1nF and 90 V. In addition, the contribution and significance of capacitance on MRR and SR was considerably higher than the effect of gap voltage. Lastly, the optimal parameters for multiple output performance were calculated at 10 nF and 90 V values.

The paper deals with the problem of stress in the connection detail of vertical supporting structures with a flat slab and possible methods for its analysis. It mainly focuses on the problem of non-axial connection of columns and walls, which is typical for today's architectural designs. The parametric study compares the effect of the distance of the connected vertical support structures on reinforcement in the discontinuity region. Three different computational methods are used to stress analysis of this region - linear Finite Elements Method in SCIA Engineer software, 2D Strut-and-Tie Model and 2D non-linear Finite Elements Method in IDEA StatiCa software. The conclusion of the study is a comparison of the accuracy of different calculation methods and also a comparison of the solved design variants in terms of shear and bending stress and specific form of reinforcement.

The paper deals with the methods of software optimization of the concrete structure in terms of environmental issues, durability, and cost. It links to previously developed software tool that enables multi-criteria optimization of a 1 m2 one-way slab. A feasibility study focused on the optimization of larger structural units, and it analyses and compares methods of concrete structures optimization in terms of environmental impacts, durability, and life-cycle cost.

When analyzing slender columns, the second-generation Eurocode FprEN [2] recommends the calculation of the bending moment envelope, which consists of both first-order and second-order moments. This paper presents the aforementioned calculation method for both braced and bracing columns, utilizing a comprehensive “general” nonlinear approach.

One of the most effective and common ways of an increasing the punching shear capacity of the flat slabs is using of shear reinforcement. An important limit during the design is the determination of the maximum punching shear resistance. The fact that the calculation of such an important value is still clearly empirical has met with criticism from many experts in recent years. Consequently, a new design model for the calculation of the maximum punching shear resistance, based on the critical shear crack theory was developed. The second generation of the Eurocode 2 (prEC2) introduces a more accurate and sophisticated design model for the determination of the upper limit of the punching shear capacity and considers several parameters. The main aim of this paper is to describe the new methodology of calculation of the maximum punching shear strength and the parameters that could influence it. The paper deals also with an assessment of the suitability of new model by comparing it with experimental results, that have been selected from a database of specimens that failed by punching at the level of VR,max.

Blast performance of concrete and ultra-high performance fiber concrete (UHPFRC) has been subject to numerous publications in the past decades. The enhanced force-deflection diagram of fiber concrete and ultra-high performance fiber concrete provide massive increase on the protective function of these materials compared to regular concrete. Nevertheless, concrete spalling cannot be fully avoided even when using UHPFRC. The next step for harmful debris ejection prevention can be supplementing the concrete specimens with steel slabs. The steel slab will not just hold the debris, but can, if properly bonded with concrete, contribute to the load bearing capacity as steel-concrete composite structure. This paper presents an overview of recent experiments on blast resistance of steel-concrete composite slabs. In total 6 pairs of specimens (dimension 1.000/1.000/150mm) were prepared, 6 specimens using regular concrete and 6 specimens using UHPFRC. One pair of specimens was reinforced by a steel mesh at 30mm cover from the soffit, one pair was supplemented by a steel plate bonded with 4 studs in the corners, at the complementary specimen pair, the concrete was also covered with a steel plate at the side subjected to blast loading, in the case of the further pair of specimens, the steel plates were connected by steel bars arranged in a mesh 150/150mm. The final 2 pairs represented steel-concrete composite slabs, in the first case, the shear studs were supplemented with a steel mesh (according to provisions of the European standard for steel-concrete composite structures), in the last case, the shear studs were replaced by a shear plate. All specimens were subjected to the same contact blast loading. The paper presents the experimental arrangement, the achieved results and a brief discussion on the structural behavior.

This paper deals with failure modes of a steel-concrete-steel sandwich loaded by pure in-plane shear. Current research together with the developed models imply that increase of reinforcement ratio leads to decrease of ductility and possibly to change a failure mode from yielding of steel in tension to crushing of concrete in compression which results in brittle failure. In order to give a reader basic information about in-plane shear behavior of a steel-concrete-steel sandwich, an analytical model is introduced. Japanese experimental program that researched a behavior of SCS panels with reinforcement ratio 2.3%, 3.2% and 4.5% is also shown. In addition to the effect of changing the reinforcement ratio, the experimental program also investigated the effect of the transverse steel plate on the ductility of test panels with a degree of reinforcement of 3.2%. The next chapter describes the methodology used by the author to model the individual parts of the model, the loads, and especially the method of supporting the model. This is followed by the presentation of the results of the analysis on the calibration and extrapolation models. Finally, a discussion is conducted on the agreement of the analysis results on the calibration models with the Japanese experimental results, followed by an evaluation of the analysis results on the extrapolation models. According to the results on the extrapolation models the critical degree of reinforcement at which a change in the failure mode of the structure occurs under in-plane shear loading is around 13%.

This paper describes an experimental investigation of the behaviour of anchors precast in Ultra High-Performance Fiber-Reinforced Concrete (UHPFRC) under static loading. Initially, the current state of the art and related experimental studies are briefly mentioned. The next part of the paper is devoted to an experimental program aimed at describing the anchorage in cement composite UHPFRC in more detail. A total of 45 pull-out tests were performed. The tests investigated the effect of the fiber quantity in volume in the UHPFRC matrix (vf), the effective embedment depth of the anchor (hef) and the position of the anchor in the mould during concreting. Finally, the results are documented, the failure mode and the shape of the concrete cone, load-displacement curves and summary tables are presented. The paper concludes with a discussion of the results and further directions for solving the problem.

The construction industry is undergoing another revolution, including the field of masonry construction. New materials and products for masonry are constantly being developed and construction details and implementation procedures are being resolved. Digitization and the introduction of automation in the masonry process (in prefabrication halls or on-site robotic bricklaying) are also an integral part of the development of the masonry construction industry. The topic of the following paper is a summary of problematic construction details of masonry buildings, i.e., the solution of the plinth console, the solution of the building opening, the bearing of lintels on the masonry and the bearing of the ceiling structure on the masonry wall. The results of laboratory tests are presented – the load-bearing capacity of the jamb of the building opening (accessory bricks / cut bricks in the jamb) and the load-bearing capacity of the lintel placed on the accessory edge brick. Furthermore, the paper deals with the construction of masonry buildings in the 21st century, including the first results of a compressive load test on masonry walls made of precast small-format units. The conclusion of the paper points out the importance of correct design details of masonry buildings before their application (programming) in software controlling the automated masonry process.

The resistance of structures to the effects of explosions is very current issue in these days. During explosion structures are subjected to extreme dynamic local loads and it is necessary to the structure and its reinforcement for this type of loading. In UHPFRC the reinforcement is evenly distributed throughout the structure in the form of dispersed steel fibres. Based on the knowledges of excellent mechanical properties of both steel and UHPFRC, there is an assumption that an appropriate combination of these materials in the sense of composite constructions should result in significantly less damage to the structure in the case of explosion. The paper is focused on the process of production of testing specimens intended for blast resistance tests. The first part of the paper describes tests elements and goals of the experiment. In the next part of the paper the design and material properties of the used concrete mixtures are described. Then production in the sense of formwork preparation and casting is described. At the end of the article, there is a brief comparison of the results achieved for specimens from UHPFRC and reference NSC.

In this paper, a series of tensile testing on wire drawing SUS 304 were conducted in order to meet the required specifications, thus, it can be utilized on the aircraft fighter components to remain stable and avoid shaking or vibration when the engine is operated. The studied material is expected to be used on flank airframes to improve its strength, wear resistance, corrosion, and aesthetic appearance. Series of tensile test has been conducted with universal testing machine (1 tonne) with modified jig configuration according to ASTM E8. The specimens were made according to the manufacture requirements such as wavy pin and straight pin connecting rod. The wire diameter has been drawing into the final diameter, which is Φ8.0 mm. From the tensile tests, yielding 1165.8 MPa and 1588.1 MPa, respectively. It is observed that the strength of woven SUS 304 wire drawing has reached the required specification to be manufactured in aircraft fastener. Factor of safety up to 2.0 has been acquired to the studied woven SUS 304 wire drawing.

Aluminum materials are used in a wide field for household appliances, aircraft, cars, ships, and construction. This research aims to obtain a new material based on aluminum magnesium silicon (AlMgSi) alloy as an alternative material to replace the steel base material in the shaft propeller product. In this paper, we will use the die-casting method to investigate corrosion resistance and the microstructure of the propeller shaft with AlMgSi aluminum alloy base material. The main base material used is 6063 aluminum alloy, with variations in the addition of Si (1, 2, 4 wt%). Alloy Al6063 is heated to a temperature of 720°C to reach a complete liquid state. Then the temperature is lowered to 645°C, then the Si element is inserted into the heating furnace and stirred. Then the temperature is lowered to 615°C, then the Mg element is added, then stirred thoroughly by a mechanical stirrer. The rotational speed of the stirrer is 70 rpm and the stirring time is 240 seconds. They were then heated to a pouring temperature of 680°C. The mold is heated to a temperature of 265°C. Then poured into the mold and pressed 7 MPa. The cast is cooled at room temperature. Then the casting products were heat treated with a solution treatment temperature of 485°C for 3600 seconds and quenched. After that, the casting products were treated with artificial aging. The results of this study show corrosion resistance increases along with the addition of variations of Silicon. The highest corrosion rate was obtained by adding Si as much as 4 wt% of 511.28 mm/y. With the addition of variations of Silicon 0 wt%, 1 wt% and 2 wt% showed the corrosion rate of 173.35 mm/y, 201.60 mm/y, 233.49 mm/y. The microstructure shows differences in grain structure. materials with variations of si 0 wt% and materials with variations of si 0 wt%, 1 wt%, 2 wt% and 4 wt% have different grain sizes. The intermediate phase (Mg2Si) was mostly formed at Si 4% wt variation. So this study proves that adding silicon elements can increase grain sizes and refiner the propeller shaft.

This study presents a research paper on the influence of heat treatment on FSW in Al 7075 materials. A comprehensive investigation was used to examine the impact of crucial weld parameters on the weld quality, including strength, flexibility, corrosion resistance, and weld structure. Additionally, the influence of temperature and tempering time on the weld quality was thoroughly examined. A series of comprehensive experiments were carried out on a 2.5 m thick aluminum 7075 plate that was welded using the Friction Stir Welding (FSW) technique. The primary objective of these experiments was to methodically examine the impact of heat treatment on the welded plate's mechanical and microstructural characteristics. The samples underwent examination both before and during heat treatment. The macroscopic and microstructural characteristics were analyzed utilizing optical microscope, tensile testing, and microhardness assessment. The impact of heat treatment is noteworthy as it substantially reduces the weld hardness while enhancing its elasticity.

Rotary friction welding (RFW) is one of the most essential creations of modern technologies because it satisfies and compensates for the shortcomings of traditional welding methods. This paper presents a study on the impact of the annealing solution process on the joints of the rotary friction welding process in Al 6061 material and with a selection of the best parameter for the procedure. The quality of the weld-joints was evaluated by a series of experiments of measuring hardness, tensile strength tests and observing the micro-structures of the specimens to achieve conclusive evidence. The aim of these experiments is to carefully and precisely examine the impact of the heat treatment process on the welded joints’ physical properties and microstructure properties. The results show that the heat treatment does enhance the mechanical properties of the material, but it is essential to conduct experiments to find the optimized parameters; or else, the properties will decrease largely.

Additive Manufacturing (AM) is a technique in constructing components from a CAD model to a finished product. This is done by depositing molten material at a specific coordinate and height. This is done continuously until the finished product has been produced. Both FDM and PLA are well-known technology and material in the AM field. Optimizing the parameters will surely provide a good reach for hobbyists, researchers, and academicians. Optimization is a process concerned with the identification of the best possible value/condition for a certain parameter. Most research papers optimize a response/factor at a time given that less than five parameters are being studied. This paper aims to optimize three mechanical properties such as strength, elongation, and modulus of elasticity. This response was optimized through seven (7) benchmark parameters conducted in mixed levels (a combination of two and three levels). This paper was able to identify the optimum level per parameter, provide insight into the significant contributors affecting the target responses, and lastly, provide a contour plot to serve as a reference of AM end-users.

3D-printed polymer component parts and spare parts are now being widely used in various applications. In this paper, the 3D printing technologies and materials for spare part production in several applications are presented. Some opportunities and challenges faced when using 3d-printed spare parts are also discussed. The acrylonitrile butadiene styrene (ABS) has mostly been used. And it was found out that the durability of the spare parts could vary depending on the application.

The global market size for Additive Manufacturing is predicted to be around USD 20 billion by 2025. The question arises whether conventional machining such as Computer Numerical Control (CNC) should be replaced by Additive Manufacturing (AM). The results presented in this paper are the outcome of an ongoing study. The overall objective of this study is a decision tool to decide which manufacturing route to adopt from a sustainability perspective. This paper will discuss the first phase of this study looking at the mechanical performance, cost and complexity of parts produced from AM and CNC. The results show that small parts are cheaper to fabricate by AM regardless of part complexity, whereas large, simple parts are cheaper to fabricate by CNC machining. These results might help in identifying manufacturing limitations of AM process in terms of mechanical performance and cost. These results will serve as inputs into a decision-making framework to decide on the most effective manufacturing route based on desired application such as in the spare parts in oil and gas industry.

This paper aims to investigate the effects of adding and increasing the concentration of halloysite nanotube (HNT) to a cellulose acetate (CA) membrane which is produced through non-solvent-induced phase separation via hand casting. Different characterization tests are performed on the nanocomposite samples: Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR), and Atomic Absorption Spectroscopy (AAS). The addition of the filler itself increases the presence of peaks and valleys on the surface of the nanocomposite membrane. The 5% HNT nanocomposite membrane has the largest peaks and valleys-both in size and number. Using the following contact times: 2, 4, and 6 hours, the adsorption capacity of the CA-HNT membranes is obtained with the aid of AAS results. The 5% HNT sample leads to a nanocomposite membrane with a higher adsorption capacity relative to that of a pure CA membrane.

The Indonesian government is committed to reducing greenhouse gas emissions under the Paris Agreement. One form of this commitment is the program to replace diesel power plants with renewable energy plants in the electricity sector. Fossil-based diesel power plant operations have disadvantages, such as relatively expensive generation costs and greenhouse gas emissions. There are three renewable energy technology options as potential substitutes for diesel power plants: a solar photovoltaic (PV) power plant integrated with a battery energy storage system (BESS), a small-scale geothermal power plant, and a micro-hydropower plant. This paper will analyze the prospects of each technology option based on its economic and environmental impact. Various technical parameters, including renewable energy potential and intermittent factors, as well as economic parameters such as investment and generation costs, are important factors for selecting prospective renewable energy generators. The analysis was carried out by calculating the levelized cost of electricity (LCOE), CO2 emissions, and oil fuel consumption for four different scenarios. The results of the analysis show that replacing the diesel power plants with micro-hydropower plants can reduce LCOE by 0.24 USD/kWh to 0.12 USD/kWh. The use of a solar PV power plant integrated with a BESS has the most potential to reduce CO2 emissions, which account for 54% of emissions from diesel power plants. Meanwhile, the potential for oil fuel reduction from this program can reach an annual average of 0.85 million kl.

Biological pollution creates significant obstacles in the operation of power plants' technical water supply cooling systems (SCS). To minimize biological pollution, methods of corrective treatment with biocides are implemented. While these biocides effectively prevent fouling of the cooling system, they can also adversely affect the environment and structural materials. By evaluating structural materials' corrosion resistance and biocides' environmental safety for the cooling water during biocide treatment, any potential issues can be identified and addressed before they become a safety or operational concern. The paper presents the results of bench tests of the corrosion resistance of structural materials SCS, corrosion aggressiveness of the biocides: sodium hypochlorite NaClO and 2, 2-dibromo-3-nitriloropionamide (DBNPA), and the results of measurements of the concentration of biocides and their decomposition products to assess compliance with environmental standards when discharging return water when applying from biocides treatment. The cooling water SCS of the Rivne NPP (Nuclear Power Plant) was chosen as the research object. Bench corrosion tests were carried out using samples of corrosion indicators from materials: steels Ст20, 08Х18Н10Т; copper alloy МНЖ-5-1 and aluminum, which are defined as analogs of structural materials of the technical water supply system of the Rivne NPP. The conditions of operation of the technical water SCS of the Rivne NPP were simulated on the test bench, and corrosion rate measurement was carried out by the gravimetric method.

This paper is to study weldability and joining characteristics of dissimilar metal welding between low carbon steel and ferritic stainless steel using ER308L and ER309L filler wires. Weldability and welded joints were evaluated by microstructure analysis and bend test. It was observed that the microstructure of the fusion zone and the bend test of the welded joint were significantly affected by welding parameters and filler wire. A welded joint prepared with high heat input using the ER309L filler wire exhibited a significant delta ferrite and austenite microstructure. In contrast, when employing the ER308L filler wire with a high intensity welding current, martensite, and carbide formed at the fusion zone. The bend property was acceptable for all the specimens, and there was no evidence of solidification cracking.

A process when different materials are combined to produce a product with multiple layers is called co-extrusion. During this process, polymers are melted in separate machines and then extrudate from different die channels. Once these channels converge, the polymers meet and flow through a single channel. The surface where the two fluids face is called “interface”. It is crucial to maintain the interface's uniformity and stability in order to achieve the desired multi-layered structure. Most of the issues in co-extrusion are related to issues that can be classified into two categories such as polymer encapsulation/interfacial distortion and die swell. To solve these problems, designers focus on improving the interface's stability. This paper examines effects of cross-section modification of the two-channel feedblock on the interface location and velocity and pressure distributions of the flow. The ANSYS software was used to simulate the co-extrusion of polymers, LLDPE and HDPE, in two-channel feedblock with rectangular, circular, and straight slot cross-sections. The results show that sharp corners increase the thickness of dead zones, while rounding them decreases the thickness. Additionally, stadium-shaped (or straight-slot) cross-section channels can move the flow with a higher maximum velocity and thinner boundary layer combining the results of rectangular and circular feedblocks.

When using the coat hanger die method for co-extrusion, the biggest challenges often involve maintaining the uniformity of the velocity distribution at the outlet of the die and ensuring the stability of the interface plane. This paper investigates the effect of different cross-section of feed channels connected to the coat hanger die on the velocity and pressure distribution of the flow at different parts of the die. Co-extrusion of LLDPE (Linear Low Density Polyethylene) and HDPE (High Density Polyethylene) polymers is simulated using ANSYS software 2020 R2 for coat hanger die design with rectangular and circular cross-sections inlet geometry; the results are compared for Carreau-Yasuda model to observe the result differences between rectangular and circular coextrusion channels connected to coat hanger die. Our results showed that rectangular cross-section feedblock generated higher values for pressure in comparison with the pressure generated by the circular cross-section feedblock. The maximum velocity generated in the circular feedblock is lower than that generated in the rectangular one, nevertheless there is more uniformity in velocity distribution in circular than rectangular cross-section.

This research paper aims to investigate the significance of considering the humidity factor during material selection in plastic product design. Humidity is a crucial environmental parameter that can profoundly influence the properties and performance of plastic materials. To ensure the long-term performance and dependability of plastic products, it is essential to comprehend and take into consideration the impacts of moisture on plastics. Humidity plays a fundamental role in the degradation and functional changes of plastic materials. Moisture absorption can lead to reduced mechanical strength and accelerated degradation processes. The selection of appropriate materials that can withstand humid conditions becomes paramount in product design. For this reason it is important to evaluate the moisture absorption properties of plastic materials. Different polymers exhibit varying degrees of moisture diffusion rates that directly affect their performance in humid environments. Evaluation of moisture measurement results allows designers to make informed decisions during material selection. For this reason, we designed an experiment to investigate which material retains less moisture. In our research, we determined 2 different experimental groups. The first of these groups (type A) was kept under normal conditions by adding glass fiber additive at different rates to the PA66 material, and each product with 3 different additives was tested for moisture for 10 days and the results were recorded. In the second experimental group, type B, the products produced with the same material and additives at the same rate were kept in water for 24 hours, then they were removed from the water and moisture tests were performed. It is aimed to make material selection by interpreting the test results and thus to facilitate the making of designs suitable for use.

This article will try to implement an ecological pavement using paper cellulose obtained from the recycling process of non-toxic sanitary waste, in order to combat environmental problems and make better use of this desire, thus preventing its increase in dumps or landfills. Therefore, tests were carried out to determine the optimal percentages of recycled paper cellulose that should be added to obtain an asphalt mixture that meets the proper parameters to be used, in this case focused on the realization of bicycle lanes. This would represent a benefit for the environment, which aims to create awareness in people, showing them the type of civil works that could improve from an adequate recycling process. Our study implements the RAMCODES methodology, which optimizes the production of briquettes, considerably reduces their number and guarantees a good result, giving way to this methodology that can be used in the future for new studies and that these are carried out in a faster and with guaranteed results.

Sustainability is very important to keep industrial growth and human development going. Concrete is the largest manufacturing material in the world and includes cement as a key bonding agent for developing strength. This paper shows that the use of chopped carbon fiber to reinforce cementitious materials improved the mechanical properties characteristics of the mortar. also proposes appropriate curing conditions for the chosen mortar. The experimental investigation was carried out to evaluate the mechanical properties of cement mortar, The study plan consists of four cement mortar mixtures with ratios include 0%, 0.25%, 0.5% and 1% of chopped carbon fiber volume fraction by weight % of cement using normal water for curing. The effects of four different methods of curing on the mechanical properties of cement mortar that have the best properties from adding chopped carbon fiber were investigated including the convectional curing. 1% carbon fibers showed the best improvement in the mortar strength.

In practical engineering applications, it usually gets the expected value of the ultimate side friction of concrete piles by the empirical parameter method. The expected value of the ultimate side friction of concrete piles cannot achieve maximum optimization due to the complexity of formation conditions and the lack of experience of technicians. To accurately obtain the ultimate lateral friction resistance of piles in homogeneous soil layers, optimize the standard value of pile ultimate lateral resistance, ensure construction safety, and save construction costs, the research method combining theoretical derivation and on-site measurement data validation was done in the manuscript. Based on the shear strength of the pile-soil interface of different materials and the shear performance of the soil around the pile, a calculation equation for the standard value of the ultimate lateral friction resistance of concrete piles in different homogeneous soil materials was derived and applied to the equation for calculating the ultimate bearing capacity of foundation pile and the axial force of pile. Finally, based on an engineering example, the calculated results were compared with the measured resultsThe research results show that in thick coarse-grained soil, as the foundation pile is short, the ultimate bearing capacity of a single pile obtained using the calculation equation deduced in this paper is less than that obtained using the empirical equation provided by the national code. In a deep cohesionless homogeneous soil material, the concrete pile shaft axial force calculation using the pile shaft axial force calculation equation deduced in this paper is close to the measured value when the foundation pile bears the ultimate load; the proposed new method has good application value.

The promise of transforming wastes from the Azores into building materials is the focus of this research. The insulation properties of some of these materials can be advantageous to the building construction sector. These materials are upcycled into non-structural components of the building such as panels for ceilings and walls as a factor to control thermal comfort economically. In this paper, insulation panels using cryptomeria waste from the carpentry industry were developed and experimentally evaluated in terms of conductivity for further study of their thermal properties, as well as life cycle analysis. Sodium silicate was used as a primary binding material along with these treated materials. The different composite panels made from the waste and surplus materials are expected to be analysed in Test cells that are built in Azores using this together with other wastes available in the region. These panels will be tested for longer periods in these test cells subjected to the local climatic conditions. The results of thermal conductivity are promising for the two composites sampled.

The end milling process plays a crucial role in shaping the material into surface structures that meet the stringent requirements of these demanding industries. The present paper aims to optimize the end milling process of Al6061 with nano tungsten carbide reinforcement at 6% by studying metal removal rate (MRR), and surface finish based on the parameters of depth of cut, feed, and cutting speed. The aluminium metal matrix composite is prepared with 6 weight percentage of nano tungsten carbide is reinforced with Al6061 alloy is casted by using stir casting method. RSM analysis is used to find the best operating condition by using L9 orthogonal array. The ANOVA result shows that cutting speed is the most domineering factor which influences the MRR and feed rate is the most influencing factor on surface roughness.

The increasing human population drives up energy consumption, particularly in the transportation and industrial sectors. Due to the limited and non-renewable availability of fossil fuels encourages various technological developments in the field of renewable energy, including biodiesel. Biodiesel is a biodegradable, non-toxic, and environmentally favorable renewable fuel. One of typical technique of biodiesel production is involving esterification reaction between fatty acids and alcohols by addition acid catalyst to enhance reaction rate. Solid acid catalysts are widely utilized for esterification reaction due to their ability to overcome the drawback of homogeneous catalysts that are difficult to separate. Solid acid catalysts can be produced from cellulose aerogel derived from coir fiber, which is then pyrolyzed into carbon aerogel and sulfonated through grafting process. Although sulfuric acid is a common sulfonic agent used in the catalyst sulfonation process, it has a lengthy grafting time. The addition of 4-aminobenzenesulfonic acid (sulfanilic acid) as a sulfonic agent alternative for sulfuric acid was investigated in this work. This paper reports the methods for preparing cellulose aerogel derived from coir fiber, pyrolysis of cellulose aerogel into carbon aerogel, sulfonation of carbon aerogel into solid acid catalyst, and application of solid acid catalyst for ethyl acetate production. The solid acid catalyst characterization tests include acid density, adsorption-desorption nitrogen analysis, SEM, and FTIR analysis. According to the adsorption-desorption nitrogen analysis results, the sulfonated carbon aerogel catalyst has a specific surface area of 220.29 g/m2. Sulfonated carbon aerogel catalyst with acid density value of 2.81 mmol/g can be obtained at the mass ratio of sulfanilic acid to carbon substrates of 1:1 and pyrolysis temperature of 700°C. The esterification reaction was carried out at 80°C and reached a conversion of 31.37% after 4 h.

The requirement for effective cooling of modern electrical and mechanical components has increased due to the desire for more compact and efficient designs. Thermal systems have used working fluids as a method for cooling systems for many years. However, technological improvements have dictated that working fluids must be more efficient for their applications. Researchers presented nanofluids as a possible solution for this issue, and they have gained a lot of attention due to their capability to enhance the heat transfer coefficient in miniaturized cooling or heating systems. The main purpose of this paper is to enhance the heat transfer coefficient in micro scales by encouraging the random motion of the particles in the nanofluid. This is accomplished by placing a nozzle between two micro-channels. The random motion of the particles is enhanced within the nozzle, increasing the heat transfer coefficient in the microchannel downstream as a result. In addition, the effects of characteristics of nanofluid are discussed briefly.

In this paper, a novel artificial staggered grid points and under-relaxation free solution for a checkerboard pattern problem in a quasi-one-dimensional, incompressible, steady, and inviscid flow is introduced. The purpose of this numerical development is to obtain a new numerical solution, which is under-relaxation factor free scheme, more accurate, and easier to implement than a conventional staggered grid scheme. The proposed numerical solution can be described as the non-staggered grid/collocated grid central difference scheme which is free of pressure checkerboard pattern or spurious oscillation. The accuracy and convergence speed of the proposed numerical scheme is benchmarked against a conventional SIMPLE-based finite volume scheme and the exact solution for the flow problem in a convergent nozzle. The numerical analysis shows that the proposed numerical scheme outperforms the SIMPLE-based finite volume scheme in terms of accuracy, computational resource, and convergence speed. Also, the proposed numerical scheme has consistent numbers of iteration over the different grid sizes in contrast to the SIMPLE-based scheme which is iteration-grid size dependent. The proposed numerical scheme can be implemented with both uniform and non-uniform grid points and shows good agreement with the exact solution for every grid size. However, the uniform grid approach produces significantly more accurate results than the non-uniform grid approach. Hence, the choice of grid distribution is still an important factor affecting the accuracy of the proposed numerical solution. The proposed numerical technique can be further extended to solve incompressible flow problem in the complex 2D-3D domain with unstructural grids.

Effective cooling of the electronic devices is of great importance to their performance. Of particular interest is when the size of the equipment has scaled down to micro level. Despite a continuous improvement over the years, there is only a handful information on gas-liquid flow in wavy microchannels. This paper presents an experimental study of the air-water two-phase flow in a wavy microchannels heatsink typically used for cooling of electronic devices. The heatsink was made from copper with 26 wavy channels. The width and the depth of each channel were 800 and 500 μm, respectively. Two cartridge heaters were used to generate a constant heat flux. Pressure and temperatures of the working fluid at the inlet and outlet of the test section were measured using a pressure transducer and thermocouples. To evaluate the benefit of using the wavy microchannels, experiment was performed using water as the working fluid. The results showed that the wavy microchannels could elevate the Nusselt number by up to 112% compared to that obtained from the straight microchannels. Experiments at various air and water flowrates in the wavy microchannels suggested that the advantages of using the air-water flow would be obvious at the liquid Reynolds number above 379.

Architecture is rapidly developing with new technologies, materials, and a desire to create more efficient and sustainable cities. It is becoming increasingly important in improving people's lives and cities by providing sustainable, more comfortable, and more aesthetically pleasing living and working environments. Architecture and construction materials have been developing rapidly in recent years, dramatically improving the quality of life and the look of cities. From energy-efficient building materials to smart management systems. ETFE is a fluorine-based plastic polymer that has become increasingly popular in the construction of modern buildings because of its lightweight and durable properties. This paper examines the characteristics of ETFE (ethylene tetrafluoroethylene) material in architecture and its application benefits in construction projects taking the Al-Abdali shopping center an example, which is located in the capital city of Amman, Jordan, where sustainable materials have remarkably grown in the past few 20 years. The study employed a direct observation method to assess the importance of ETFE sustainable material in the shopping center in Amman. Data from previous research and studies that are mainly related to construction materials were also included to build the base of this study. The study's results provide both an overview of ETFE material characteristics in architecture and an insight into its application in the chosen case in Amman. This paper contributes to understanding ETFE material characteristics, its application in architecture, and its potential for future use in similar projects.

Trabecular bone undergoes changes in its morphology when subjected to external loading. This paper analyses changes in morphological parameters of individual trabeculae (trabecular thickness and bone volume fraction) in response to loadings at different directions: 0°, 20°, 45°, 70° and 90°. It was found that increase in the load incline caused increase in trabecular thickness and bone volume fraction. In addition, the equilibrium-state trabeculae obtained from adaptation to load at 90° (shear loading) had the highest axial and lateral stiffnesses, as compared to trabecular geometries obtained from other loading scenarios.

Ultrasonic Lamb waves have gained popularity in non-destructive testing of plate-like structures due to their advantages such as low attenuation, high sensitivity, and wide detection range. This paper presents a novel baseline-free method for inspecting curved plate-like structures based on reciprocity loss. The method combines a modified damage imaging algorithm, a baseline-free detection method based on time reciprocity, and a calculation method for damage index values using the analysis of the focus position of time reciprocity signals. Experimental results demonstrate favorable effectiveness of the baseline-free method in detecting and locating multiple defects in the curved plate made of composite laminate.

Researchers have become interested in functionally graded concrete (FGC) in recent years due to its potential to enhance the desired performance. Functional gradation can be carried out in a continuous or stepped/layered manner. Most studies have been conducted on two layered FGC beams by substituting the richer mixes in either tension or compression zone. Previous studies have incorporated and presented the structural design approach of such two-layered beams. Moreover, the layer in the compression zone was assumed to bear entire compressive stresses. Previous studies exhibited savings in cement by up to 37% using a layer of the concrete class defined by exposure conditions around reinforcement and the concrete of minimal structural class. However, using structural concrete of minimal class in the remaining segments may result in a higher reinforcement requirement, reducing the benefits of savings in embodied CO2 offered by reduced cement consumption. This paper examines how designing the beam as a Functionally Graded Reinforced Concrete (FGRC) beam following Indian Standard 456:2016 affects the cost and embodied CO2 based on cement and steel consumption through the durability approach of design, wherein the substitution of the layer is considered in the tension zone. The study revealed that a 10% and 16% reduction in cost and embodied CO2 could be accomplished.

This paper serves as basis for subsequent studies investigating a potential material and manufacturing method selection for producing lattice structures to be used as energy absorption device, such as in novel wearable protective gear. Four additively manufactured plastics from two additive manufacturing methods are examined in detail. Polyamide 12 specimens produced on two Powder Bed Fusion (PBF) machines are compared against specimens produced on a stereolithography (SLA) printer using a standard and an engineering-grade resin. A comprehensive analysis of their mechanical properties is presented by measuring their densities as well as tensile, fatigue, and impact properties. In addition, Poisson’s ratio of the resin materials is estimated using Digital Image Correlation (DIC).

In this paper present the effects of 316L steel in the environment of repeated heat load, and the impact of the thermal load on fatigue life. Using thermal fatigue experiments and ABAQUS software, rain flow counting method is used to simplify the strain cycle spectrum of stress load. The Coffin-Manson nonlinear empirical equation was established based on thermal fatigue experiments, and the fatigue life estimation was completed in accordance with the Miner damage accumulation rule and FE-SAFE fatigue software. The test rods were respectively placed at room temperature and heated at 250°C for water cooling for tensile testing. Fatigue tests were performed with 5 strain parameters (0.8%, 0.7%, 0.6%, 0.5% and 0.4%). ABAQUS and FE-SAFE software used to study 316L testing rod fatigue life verification analysis. A composite heat exchange system model made of 316L was designed for the case study. It is found that the fatigue life after heating is reduced by 35% to 12% from the experimental results and numerical simulation calculation. Therefore, when the 316L steel is subjected to thermal fatigue, the fatigue life will be reduced. The research results can provide a reference for the design of heat exchangers using 316 steel in various fields.

The role of non-metallic inclusions is gaining increasing attention in steel research. Various inclusion characterisation techniques and methods are utilised in order to obtain reliable and accurate results. Automatic inclusion measurements carried out using field-emission scanning electron microscope with energy dispersive spectroscopy produces a large amount of data about detected inclusions in the scanned area. The data obtained must be processed and analysed in one way or another, for example, to classify the inclusions or construct size distributions. Until now, a Matlab script has been used to determine the phase composition of inclusions, and to classify them accordingly. The Matlab script has acted as the basis for the recently developed Karakterizer tool, written in Python. In addition to less restricted use, the recent advances include a graphical user interface. This paper demonstrates the use of Karakterizer tool in characterising inclusions with examples of direct-quenched martensitic steels with a yield strength of 1000 MPa.

LVD Company NV and Kawasaki Heavy Industries, ltd. developed the cutting-edge, high performance CNC press brake [1] for high accuracy/precision bending of approx.10m (L) by 2.5m (W) size aircraft skins. Those skin sheets have complex shapes which include mainly machine milled thickness reduction area called pockets, thickness tapers, cutouts for the windows and doors. Due to those characters, the materials have large thickness variation between less than 2 mm and more than 11 mm in a single skin sheet. Here in this paper, the overview of this intelligence press brake equipment and its forming process are described. The materials with complex shapes described above can be bent accurately including material edges with the features of the press brake which are the synchronized material handling system, 210 numbers of variable punches, the special die suitable for the variable punches, the curvature measurement devices, and an automated bending mechanism with curvature feedback /feedforward. In addition, cardboard-like-filler jigs which are used to make thickness variations flat in a traditional bending process and shims to adjust regional press strokes can be eliminated, which reduce significant process time and product quality without worker’s superior skills. As a result, full automation of accurate bending process of aircraft skins have been achieved.

Compared to discrete manufacturing, sheet material is produced in a continuous manufacturing process with several dimension and volume changes. This includes thickness reduction by rolling and width and length changes by slitting and cross-cutting. Along the process chain, this happens several times using different manufacturing facilities, where each work step is usually followed by coiling. Each of these machines records high-frequent production data in a time-based manner. General research topics in this field [1, 2] aim to assign the time-based records to the related section of the alloy sheet (length-based). This paper deals with challenges concerning the identification of strips and the assignment of the corresponding process data. In a particular application, the coil orientation for each process step is calculated and documented for a given part of the production process. This is a necessary precondition for further process data assignment. Furthermore, the effort for certain manual tasks can be reduced by using the calculated coil orientation.