Internal Shapes Research Articles

Weaknesses of steady state analysis when used for selecting solar air heaters

The paper highlights the constrains faced by the user when choosing the most appropriate solar collector from a set of collectors belonging to the same category. Two basic kinds of one porous and one non-porous with single flow/pass flat solar air heaters were tested. The collectors have the same size but different internal shapes and absorber materials. The two collectors were tested and a shading procedure was implemented in order to emphasize several aspects related to the thermal inertia of the collectors. Comparison has been made between the efficiency values obtained experimentally. The shade test shows a faster decrease of the outlet air temperature for V-porous absorber collector in comparison with the U-corrugated absorber collector i.e. 6 °C and –3.5 °C respectively in a time interval of 74 s. Exposing the collectors on a fresh heating cycle under a low stability radiative regime (450–750 W/m2) one observe that 60% of the first 180 s the corrugated collector outperforms the porous collector; after that interval of time the porous collector becomes more effective. The low thermal inertia of the solar air collectors yields high variation of the thermal efficiency in days with low stability of the radiative regime. In such days, using measured series of solar irradiance data with long sampling period between two successive measurements does not allow a proper choice of the most appropriate solar collector type.

Experimental and numerical investigation in to the axial load behaviour of profiled composite walls reinforced by embedded tubes with comprehensive parametric study

This paper presents experimental and numerical investigation on the axial load behaviour of profiled composite wall (PCW) consisted of two profiled steel sheet (PSS) in-filled with concrete and reinforced with/without embedded cold formed steel tubes (CFSTs). This type of composite walls was designed to resist the in-plan axial loading (bearing wall) in buildings designed with shear walls system. The results of three different FE models, namely, NCW-FE, Oct-FE and OCT-L-FE were accurately verified with the results of three experimental specimens, namely, NCW-Exp, Oct- Exp and OCT-L- Exp. Then, after the verification study for the FE models a comprehensive parametric study was presented to show detailed information about the positive effect of the internal CFSTs thickness, number and cross sectional shapes with and without stiffeners on the axial load behaviour of the PCW. The effect of the PSSs thickness and the concrete compressive strength on the axial load resisting behaviour of the PCW was studied as well. The results of this study proved that the effects of the embedded CFSTs reduced the local buckling of the PSS and increased the ductility with the axial load resistance of the PCW.

EVALUATION OF THE SCATTER OF LIQUID LAUNCH VEHICLE POGO OSCILLATION AMPLITUDES DUE TO THE INFLUENCE OF THE SCATTER OF INTERNAL FACTORS

Almost all liquid launch vehicle developers faced the problem of ensuring stability in relation to POGO oscillations. The level of POGO amplitudes oscillations of the launch vehicle can be significantly affected by the scatter of internal factors. The study aims to create a mathematical model that can determine the range of POGO amplitudes in liquid launch vehicles. This will be demonstrated through the example of the Dnipro launch vehicle, which is affected by a variety of internal factors that cause its POGO amplitudes to vary. We developed the non-linear non-stationary mathematical model of POGO oscillations of the prototype of the Dnipro space launch vehicle. The model is built by taking into account the two lower vibration modes of the LV structure, two lower oscillation modes of the oxidizer feedline, and the first oscillation mode of the fuel feedline of the propulsion system. Modeling of dynamic processes was conducted in a combination of four liquid rocket engines based on the schematic of the staged rocket engine. The simulation takes into account cavitation phenomena in the engine pumps and delay times in the gas generators’ chambers. We have developed a method for determining the scatter of the POGO oscillations caused by the action of internal factors, which is based on the use of the LP uniformly distributed sequences. As internal factors, the frequencies, decrements, and shapes of LV structural oscillation modes, the values of pressurization of the propellant tanks, and the engines’ specific thrust impulses were considered. Based on the results of the calculations, the dependence of the POGO amplitudes in two regions of LV instability was determined, and the lower and upper enveloping curves for the POGO amplitudes were constructed. It is shown that the maximum POGO amplitudes oscillations in the first region of instability lie in the range from 0.23 g to 0.72 g and in the second region of instability — from 0 g to 0.60 g. Variants of combinations of internal factors, which provided the largest and smallest values of POGO amplitudes, were analyzed. This made it possible to determine the internal factors, the scatter of which has the greatest effect on the POGO amplitudes scatter: frequency, decrement, shape coefficients of oscillations of the oxidizer feedlines and the LV 1st mode structural longitudinal oscillations in the payload cross-section.

Numerical and experimental investigation into tool-workpiece interaction in flexible abrasive tool finishing

The present work examines the finishing performance of oxygen-free high conductivity (OFHC) copper using a fabricated flexible abrasive tool. It is challenging to finish soft materials like copper and aluminium using traditional finishing techniques due to frequent scratching. Flexible finishing tool can protect the surface integrity of the workpiece samples during finishing action. Flexible abrasive tools are fabricated using solvent casting method. This method fabricates the flexible tools with homogeneous abrasive dispersion and an open-cell porous structure. The developed tool is self-sharpening and self-lubricating and can finish soft materials efficiently. The flexible abrasive tools can be fabricated in different shapes and sizes to finish internal features and complex shapes. The interaction between the tool and workpiece is examined by the forces exerted by the flexible tool on the workpiece. The areal surface roughness of the finished surface is reduced to 33 nm from its initial roughness of 937 nm after 20 min of finishing a pre-defined region. Theoretical analysis is carried out to estimate contact pressure using Hertz contact theory. The results obtained from numerical and theoretical analysis have a close correlation with the experimental results. The maximum deviation of peak contact pressure obtained in theoretical estimation and numerical analysis from experimental results is found to be 20.73 % and 12.83 %, respectively. As the model includes the basic physics of the tool-workpiece interaction, the results can be improved with the inclusion of micro-level analysis of fluid-filled flexible abrasive tools with embedded abrasives.

Insights for improving the electromagnetic properties of conductive nanocomposites manufactured with carbon nanotubes

Additive manufacturing (AM) technologies offer many advantages that are attractive for electromagnetic compatibility (EMC) in industrial environments, and possibilities include customizable sizes and new complex internal shapes (infill) for parts. The polymeric nanocomposites with carbon-based nanomaterials, such as multi-walled carbon nanotubes (MWCNT), are of great interest and can be used for the development of functional electromagnetic components using the material extrusion (MEX) technique,. However, the literature lacks a deeper understanding of the relationship between the MEX process, the slicing parameters, the structure generated, and the electromagnetic behavior of the nanocomposite-based parts. This work studied the influence of building direction, various infill patterns, and orientations of acrylonitrile-butadiene-styrene copolymer (ABS)/MWCNT nanocomposite with 3 wt% of MWCNT on the manufacture of samples by additive manufacturing, with the evaluation of the electromagnetic interference shielding effectiveness (EMI SE) and reflection loss (RL) performances of the prepared materials. The correlation between geometric parameters and the EM response was explored and corroborated with computational simulations. The results pointed out that parts using the building direction (ZX and XY) may achieve similar shielding results depending mainly on the infill orientation. When the deposited filament (or the entire layer) is aligned with the electric field, the EM shielding behavior is maximized. In contrast, when the deposited filaments are orthogonal to the electric field, the behavior is impaired. The computational simulation of the rheological flow of the nanocomposite and the EM behavior corroborated these findings, and the MEX sample matched the attenuation of the injection molded sample behavior for a greater thickness (16 dB at 9 mm). Additionally, the RL behavior of the parts with different infill patterns and thicknesses was studied. These results indicated that the MEX process might be a promising way to promote the reflection loss (RL) behavior of conductive materials that, in bulk, would not promote such a good response. The best RL performance found was − 18 dB and 1.4 GHz bandwidth for the 50 wt% hexagonal infill pattern with an extra layer in the middle of the body sample.

Evaluation of strategic orientation-led competitive advantage: the role of knowledge integration and service innovation

PurposeThis paper aims to derive a model that explores how the interplay between knowledge integration capability and innovation impacts strategic orientation, leading to the attainment of sustainable competitive advantage. The study considers the constituents of strategic orientation, namely, customer orientation, competitor orientation and technology orientation, as the basis for achieving sustainable competitive advantage. The study suggests that the firm’s capacity for integrating external and internal knowledge shapes how strategic orientation influences sustainable competitive advantage through service innovation.Design/methodology/approachThis empirical research relies on qualitative and quantitative data gathered from telecom professionals to assess how knowledge integration and service innovation influence sustained competitive advantage. Structured equation modeling is used to examine the model and its interrelationships.FindingsThe research establishes significant relationships between strategic orientations, knowledge integration capability, service innovation and sustainable competitive advantage. Knowledge integration capability and service innovation are found to mediate the relationship between strategic orientations and the achievement of sustainable competitive advantage.Practical implicationsThe study highlights the significant contribution of a firm’s knowledge integration capability in driving service innovation, especially in technology-intensive service industries facing hypercompetition. It also advocates prioritizing technology orientation and integrating knowledge from internal and external sources for competitive advantage.Originality/valueTo the best of the authors’ knowledge, this study is the first to model the effect of knowledge integration capability and service innovation on strategic orientation-led sustainable competitive advantage.

Influence of internal angle and shape of the lining on residual stress of Class II molar restorations

Polymerization shrinkage is a major side effect of resin composite materials that affects the success and longevity of caries restorations. This study was to analyze the effect of the internal angle and shape of the lining on the shrinkage residual stress of dental restorations in Class II mesio-occlusal-distal (MOD) cavities through finite element analysis (FEA). A 3D reconstructed model of a human mandibular first molar was created from micro-CT images, and then the tooth was prepared as a Class II MOD cavity. 3D models of four regular internal corner shapes of Class II MOD cavities with different internal angles of lining and one 90° filleted corner model were created. The thermal expansion technique was applied to approximate the shrinkage impact of composite resin polymerization in the FE software ABAQUS. Von Mises stress was taken as a metric. The results showed that the level of residual stresses in the Class II MOD cavities was greatly dependent on the internal angle of the lining. The maximum von Mises stress in tooth tissue decreased as the internal angle of the lining increased. The internal shapes of the lining had no obvious effect on the stress, and the filleted corner model had less stress. This lining strategy is appropriate for Class II MOD cavities with serious loss of tooth tissue.

Fabrication of Tuneable Tissue-Mimicking Phantom for Optical Methods.

Tissue mimicking optical phantoms are commonly used to calibrate or validate the performance of near-infrared spectroscopy or tomography. Human tissue is not only irregular in shape, but also exhibits dynamic behaviour, which can cause changes in optical properties. However, existing phantoms lack complex structures and/or continuously varying optical properties. The project aimed to design, fabricate and characterise a novel phantom system for testing near-infrared imaging devices. We designed a dynamic tissue-mimicking phantom platform which features arbitrary internal shapes and variable optical properties. The solid part of phantom was made of silicone material with absorbing and scattering properties similar to the brain. We printed a semi-ellipsoidal sphere (a major axis=20 mmand a minor axis=the third axis=12 mm) using a water-soluble material polyvinyl alcohol (PVA). The shape was placed at the depth of 5 mm in the silicone bulk. The desired internal hollow structure was formed after curing and submerging the phantom in water. The liquid part contained dyes and Intralipid. The optical properties within the internal shape were adjusted by injecting the liquid solutions of varying dye concentrations with a syringe pump at a constant rate. The phantom was measured by a frequency domain near-infrared spectroscopy (FD NIRS) and imaged by a time domain near-infrared optical tomography (TD NIROT). A dynamic phantom system with a complex internal structure and varying optical properties was created. Changes in light intensity were detected by the FD NIRS. The internal structure of this phantom was accurately recovered by NIROT image reconstruction. We successfully developed a novel phantom system with an internal complex shape and continuously adjustable optical properties. This phantom was accurately imaged using NIROT, and the changing light intensity was detected by NIRS. It is a valuable tool for validating optical technologies.

Adsorptive removal of biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) from greywater using activated carbon prepared from tropical almond and palm kernel shells

This study assesses the reduction of 5-day biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) of household greywater using palm kernel activated carbon (PKAC) and tropical almond activated carbon (TAAC) produced from locally available materials in a kiln at 800oC and activated using steam at a flowrate of 120 mL hr-1. Brunauer-Emmet-Teller (BET) surface area determination revealed that PKAC had a larger surface area than TAAC. Scanning electron microscope (SEM) imagery of the carbons also revealed amorphous and large internal shapes for TAAC while crystalline and closed packed shapes for PKAC. X-ray diffraction (XRD) analysis indicated that the major component present in the PKAC and TAAC was carbon and other allotropes of carbon. Batch results showed that reduction of BOD5 and COD was affected by particle size. The maximum percentage reduction of BOD5 and COD by PKAC was 76% and 65% respectively while reduction by TAAC was 62% and 52% respectively. The adsorption process was well described by the Freundlich adsorption isotherm. The studies showed that PKAC is a better adsorbent for reducing BOD5 and COD from domestic greywater as compared with TAAC. The PKAC is a potential low-cost adsorbent for BOD5 and COD removal from domestic greywater.

"They don't care about people; they only care about the money": the effects of border enforcement, commodification and migration industries on the mobility of migrants in transit through Mexico.

How does border enforcement affect the mobility of migrants and refugees in countries of transit? What impact does it have on migrants' bodily experiences of mobility and their reliance on actors of the migration industry? While the externalization of borders affects undocumented people by increasing their vulnerability to violence during transit, the impact of the migration regime on the social construction of inequalities in every-day interactions and its relationship to the capacity for mobility has not been studied in depth. This article intends to bridge this gap: based on ethnographic fieldwork I conducted between 2013 and 2019, this article analyzes the relation between immigration enforcement and the mobility strategies of migrants and refugees, particularly women. It focuses on the intertwining of border enforcement and violence and their impact on people's bodily mobility experiences in transit through Mexico along intersecting lines of inequality such as race, class, gender and nationality. First, I analyze how border enforcement contributes to internal bordering, thereby increasing the vulnerability and dependence of migrants on brokers for mobility; second, it looks at the bodily experiences of women in transit and the ways in which internal bordering shapes gendered power hierarchies among actors in the field of mobility. The analysis shows how women negotiate mobility and bodily integrity in social interactions with different actors and how they face constraints resulting from the gendered hierarchies to mobility on routes of transit. Furthermore, it demonstrates how women's bodies have become a privileged site for the construction of a 'body politic' exploitable by others, since border enforcement has contributed to weakening the possibilities of negotiating mobility and bodily integrity in transit.

Surface direct conversion of 511 keV gamma rays in large-area laminated multichannel-plate electron multipliers

We have used the TOPAS simulation framework to model the direct conversion of 511 keV gamma rays to electrons in a micro-channel plate (MCP) constructed from thin laminae of a heavy-metal-loaded dielectric such as lead-glass, patterned with micro-channels (LMCP). The laminae serve as the converter of the gamma ray to a primary electron within a depth from a channel-forming surface such that the electron penetrates the channel surface (‘surface direct conversion’). The channels are coated with a secondary-emitting material to produce electron multiplication in the channels. The laminae are stacked on edge with the channels running from the top of the resulting ‘slab’ to the bottom; after assembly the slab is metalized top and bottom to form the finished LMCP.The shape of the perimeter of a lamina determines the dimensions of the slab at the lamina location in the slab, allowing non-uniform cross-sections in slab thickness, width, and length. The slab also can be non-planar, allowing curved surfaces in both lateral dimensions. The laminar construction allows incorporating structural elements in the LMCP for modular assembly in large-area arrays.The channels can be patterned on the laminae surfaces with internal shapes and structure, texture, and coatings optimized for specific applications and performance. The channels can be non-uniform across the LMCP and need not be parallel in either transverse direction.Surface direct conversion of the gamma ray to an electron eliminates the common two-step conversion of the gamma ray into an optical photon in a scintillator followed by the conversion of the photon into an electron in a photodetector. The simulations predict an efficiency for conversion of 511 keV gamma rays of ⪆ 30% for a 2.54 cm-thick lead-glass LMCP. The elimination of the photocathode allows assembly at atmospheric pressure.

Additive manufacturing of titanium and nickel- based superalloys: A review

This paper reviews on the rapidly emerging manufacturing technology known as additive manufacturing (AM) which utilizes computer-aided design (CAD) data to produce three-dimensional objects by building up layers of material. One of the most promising areas of application for additive manufacturing is in the use of Titanium and Ni-based superalloys for aerospace and biomedical applications. These superalloys have exceptional strength and corrosion resistance, making them ideal for use in parts that are exposed to high temperatures and harsh environments. AM allows for the precise control of the microstructure of these materials, leading to improved mechanical properties and performance. Additionally, AM could be utilized to produce internal structures and complex shapes that would be hard or unattainable to achieve with conventional manufacturing methods. A detailed discussion of applications of AM in biomedical, aerospace, nuclear and automobile industries which deal with Titanium and Ni-based superalloys is the primary focus of this paper.

A STUDY ON CONVERGENCE MODELING OF CULTURAL ARTIFACT USING X-RAY COMPUTED TOMOGRAPHY AND THREE-DIMENSIONAL SCANNING TECHNOLOGIES

Abstract. Optical three-dimensional (3D) scanning technology is extensively used for digital recording and shape analysis of cultural heritage because it is simple to obtain precise surface shape and color information. In addition, X-ray computed tomography (X-ray CT) is used to record and analyze the internal shape of cultural heritage. However, while the 3D shape acquired by X-ray CT technology is excellent for visualizing the internal shape, expressing the high resolution of the surface shape is difficult. If the benefits of each technology are used to digitize the inside and outside of cultural heritage, the results of surface shape recording based on 3D scanning can be advanced, and various stereoscopic analysis can be performed. Therefore, an optimization modeling process that combines X-ray CT and optical surface scanning is required to record both internal and external shapes of cultural heritage. In this study, optimization modeling methodology was applied to cultural heritage by combining X-ray CT technology and optical 3D scanning technology. Based on the models obtained through both technologies, a mesh-based optimization convergence modeling methodology considering internal and external surface shapes and color is organized. Furthermore, because the X-ray CT data has a characteristic of a voxel base, it is determined that additional convergence methods, including internal voxel data, are required, and a voxel-based optimization model process is established concurrently. Following that, two convergence modeling methods were applied to each of the deer-shaped horn cup artifacts that had an interior shape. As a result, the 3D convergence model creation and mapping optimization process, which can reveal important internal and external information about artifacts such as surface color, fine shape, and internal structure, can be improved. This 3D convergence modeling methodology was able to supplement the two technologies while preserving the benefits of optical 3D scanning and X-ray CT technology. This is thought to contribute to the expansion of the digital recording process from a single technology to multiple technologies. The X-ray CT-based convergence modeling pipeline is expected to be an opportunity in promoting the revitalization of X-ray CT technology in the cultural heritage field because it can be used for a wide range of purposes such as shape analysis, preservation status evaluation, monitoring, restoration, and reproduction.

Computational fluid dynamics modeling of contaminant transport with adsorption filtration inside planar-shaped air-purifying respirator canister

We performed computational fluid dynamics (CFD) simulations of the contaminant transport with adsorption filtration inside a planar-shaped air-purifying respirator (APR) canister and predicted the breakthrough times of the canisters with various internal shapes. The numerical modeling of the adsorption process based on the backward differentiation formulas, which comprise the implicit method implemented in COMSOL Multiphysics, demonstrated the validity through the simulations of the fixed-bed column breakthrough test. Model parameters were estimated by applying Bayesian inference to the breakthrough test and pressure drop measurement data. Previous CFD studies assessed the filtering efficiency based on the local flow speed and mean air age; this approach replaced adsorption modeling, which is computationally expensive. We tested six planar-shaped APR canisters and observed that the dead zone near the walls in the air age field does not appear in the contaminant transport simulation with adsorption modeling. We identified that the velocity fields inside the filter determined the breakthrough distributions. Further, we confirmed that the breakthrough time was more related to the maximum flow speed inside the filter and less with local mean air age. We demonstrated the importance of simulating contaminant transport with adsorption modeling for the APR canister and reliability of the alternative indices.

Corrosion Performances of Selective Laser Melting Ti6Al4V Alloy in Different Solutions

Selective laser melting (SLM) can fabricate titanium and its alloy components with both elaborate internal architectures and complex shapes without geometric constrictions. The corrosion resistance of SLM-produced Ti and its alloy is crucial in some applications such as marine and biomedical environments. Here, potentiodynamic polarization and electrochemical impedance spectroscopy were used to evaluate the corrosion behaviors of SLM-produced Ti-6Al-4V in the four corrosive media (simulated body fluid (SBF), phosphate buffered saline solutions (PBS), 3.5 wt.% NaCl aqueous solution, 15 wt.% NaCl aqueous solution). The relevant results demonstrate the inferior corrosion resistance of the SLM-produced Ti-6Al-4V sheet compared with the commercial casting Ti-6Al-4V sheet in the four solutions. The corrosive current density of SLM-produced Ti-6Al-4V in PBS solution is 1.78 μA cm−2 and 7.065 μA cm−2 in 15 wt.% NaCl solution, and the values of charge transfer resistance for SLM-produced Ti-6Al-4V in the four solutions are in the order: 17.9 kΩ cm−2 (in 15 wt.% NaCl) < 25.2 kΩ cm−2 (in 3.5 wt.% NaCl) < 28.1 kΩ cm−2 (in SBF) < 39.8 kΩ cm−2 (in PBS), demonstrating the best protective performance of the passivation film on the SLM-produced Ti-6Al-4V sheet in PBS.

Analysis of Internal Nasal Valves Shapes and Angle due to Nasal Obstruction in Asian Nose

BACKGROUND
 Internal nasal valve (INV) is widely discussed because it is believed to have a role in structural nasal obstruction. Caucasian has a rather acute angle of INV due to the known geometric of their nose. Whilst Asian generally has broader, thicker, and bigger anthropometric proportion of nose than Caucasian. Asia is vastly diverse in ethnicity, one can only assume that Asian INV may be differ in shape and larger in angles compare to Caucasian, due to the minimum publication addressing this issue.
 AIM
 To report the anatomy of INV and its angle in obstructed Asian noses.
 METHOD
 A case control study was conducted. Forty cases of nasal obstruction and 80 controls without nasal obstruction. Both groups were evaluated using Nasal Obstruction Symptom Evaluation (NOSE) questionnaire, rigid nasal endoscopy and active anterior rhinomanometry (AAR). Anatomy and angle of INV was later measured using digital image analysis.
 RESULT
 Six basic INV shapes were seen throughout both groups, many has different shape combinations. Most commonly (more than 60%) observed shape in both groups were the occupied by nasal septal body (NSB). The right INV angle in case group was 15,5º ± 10,1º (p = 0,123) and left INV angle was 17,2º ± 9,0º (p = 0,022). In control group, the right INV angle was 19,6º ± 11,8º (p = 0,123) and left INV angle was 23,2º ± 12,5º (p = 0,022).
 CONCLUSION
 It is shown that most common shape of Asian INV in both groups, is the occupancy by NSB. Internal nasal valve angle in obstructed nose is narrower in comparison to those without nasal obstruction. This study also demonstrates Asian, particularly Indonesian, has a wider angle than Caucasian.

Simulation of Hand Anatomy Using Medical Imaging

Precision modeling of the hand internal musculoskeletal anatomy has been largely limited to individual poses, and has not been connected into continuous volumetric motion of the hand anatomy actuating across the hand's entire range of motion. This is for a good reason, as hand anatomy and its motion are extremely complex and cannot be predicted merely from the anatomy in a single pose. We give a method to simulate the volumetric shape of hand's musculoskeletal organs to any pose in the hand's range of motion, producing external hand shapes and internal organ shapes that match ground truth optical scans and medical images (MRI) in multiple scanned poses. We achieve this by combining MRI images in multiple hand poses with FEM multibody nonlinear elastoplastic simulation. Our system models bones, muscles, tendons, joint ligaments and fat as separate volumetric organs that mechanically interact through contact and attachments, and whose shape matches medical images (MRI) in the MRI-scanned hand poses. The match to MRI is achieved by incorporating pose-space deformation and plastic strains into the simulation. We show how to do this in a non-intrusive manner that still retains all the simulation benefits, namely the ability to prescribe realistic material properties, generalize to arbitrary poses, preserve volume and obey contacts and attachments. We use our method to produce volumetric renders of the internal anatomy of the human hand in motion, and to compute and render highly realistic hand surface shapes. We evaluate our method by comparing it to optical scans, and demonstrate that we qualitatively and quantitatively substantially decrease the error compared to previous work. We test our method on five complex hand sequences, generated either using keyframe animation or performance animation using modern hand tracking techniques.

Wpływ kształtu wzmacniających profili okiennych na wytrzymałość i sztywność skrętną okien

Leading European manufacturers of profiles intended for the production of construction joinery currently use mainly PVC profiles with various configurations of external and internal shapes, allowing the production of functional products due to their intended use, shape, possibility of building them, maintaining color and maintaining low thermal transmittance coefficients of profiles. It is important to obtain high cross-sectional strengths, especially for torsion and bending. It is related to high wind loads of structures. A profile is made of a PVC with a low Young’s modulus compared to other materials, and thus it has low stiffness and strength indicators. This leads to relatively easy deformation of the joinery profiles during assembly. To avoid this unfavorable effect, the PVC profiles are reinforced with steel sections. Currently, in the industry producing PVC profiles, open steel reinforcement profiles are almost exclusively used. This solution is very disadvantageous for reasons of stiffness. However, manufacturers use such profiles primarily for technological and price reasons. Closed profiles pose many technological problems in their production and are approx. 30% more expensive compared to the corresponding open profiles. This paper presents research on the use of closed steel stiffening sections in place of open profiles. The main advantage of stiffening closed profiles is many times greater bending and torsional stiffness compared to open profiles. The theoretical and experimental studies carried out for selected cross-sections have shown that the stresses in a closed profile are several times lower than in an identical open profile, and the torsional stiffness of a closed profile is even several dozen times higher than that of an identical open profile.

(Digital Presentation) Developing Meat Alternatives with Screw-Based 3D Food Printing

Food 3D printers are next generation devices that can fabricate food products with complex internal structures and external shapes, and are expected to be used as devices for producing food products with shapes and textures that meet people's preferences, but also provide requirement of seven essential factors for a balanced diet: carbs, protein, fat, fiber, vitamins, minerals, and water [1, 2]. The food 3D printer can handle two types of food at the same time, and since it can form food in two colors, it can make food that cannot be made with a syringe nozzle. On the other hand, there are concerns about the shortage of protein supply due to the increase in population, and alternative meats that are not derived from livestock are attracting attention [3]. Currently, there are few reports of research on alternative meats using food 3D printers, and in particular, 3D modeling of alternative meat that reproduces the texture of actual meat has not been done much. In this study, we have developed a food 3D printer technology that enables the modeling of alternative meat that reproduces the texture of actual meat. We have investigated the composition of alternative meat materials suitable for 3D printing based on soy protein, and the material properties of the dough using a rheometer. In future, we will report on the movement and layering during the 3D food printing process.

ИССЛЕДОВАНИЕ ХАРАКТЕРИСТИК ПРОЧНОСТИ СИНТЕЗИРОВАННОГО СПЛАВА СИСТЕМЫ Co–Cr–Ni–W–Ta

Additive manufacturing is increasingly used in the aviation industry. Its main feature is the manufacture of parts of complex external and internal geometric shapes without increasing the cost of their production. To calculate the resource of nodes and reliable operation of new equipment, it is necessary to have a set of calculated values of characteristics of structural strength, including the characteristics of tensile, creep rupture and high-cycle fatigue (HCF). The study of characteristics of tensile, creep rupture and HCF of the Co–Cr–Ni–W–Ta alloy obtained by the method of selective laser melting (SLM) is presented in this paper.