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33 pages, 19731 KiB

Open AccessArticle

Comparative Study of Physicochemical Properties of Biochar Samples Derived from Nutshells as a Solid Fuel for Direct Carbon Solid Oxide Fuel Cells

by Magdalena Dudek, Bartosz Adamczyk, Anita Zych, Katarzyna Król, Przemysław Grzywacz, Krystian Sokołowski, Krzysztof Mech, Maciej Sitarz, Piotr Jeleń, Magdalena Ziąbka, Maja Mroczkowska-Szerszeń, Małgorzata Witkowska and Joanna Kowalska

Materials 2025, 18(9), 2112; https://doi.org/10.3390/ma18092112 - 4 May 2025

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Abstract

This paper presents the results of an investigation into the effect of the physicochemical properties of carbon chars (biochars) on the performance of direct carbon solid oxide fuel cells (DC-SOFCs). Biochars were obtained from walnut, coconut, pistachio, hazelnut and peanut shells by pyrolysis [...] Read more.

This paper presents the results of an investigation into the effect of the physicochemical properties of carbon chars (biochars) on the performance of direct carbon solid oxide fuel cells (DC-SOFCs). Biochars were obtained from walnut, coconut, pistachio, hazelnut and peanut shells by pyrolysis at a temperature of 850 °C. The results of structural studies conducted using X-ray diffraction and Raman spectroscopy reflected a low degree of graphitisation of carbon particles. Biochar derived from walnut shells is characterised by a relatively uniform content of alkali elements, such as sodium, potassium, calcium, magnesium and iron, which are natural components of the mineral residue and act as catalysts for the Boudouard reaction. This study of gasification of biochar samples in a CO₂ atmosphere recorded that the highest conversion rate from solid phase to gaseous phase was for the biochar sample produced from walnut shells. The superior properties of this sample are directly connected to structural features, as well as to the random distribution of alkali elements. DC-SOFCs involving 10 mol% of Sc₂O₃, 1 mol% of CeO₂, 89 mol% of ZrO₂ (10S1CeZ) or 8 mol% of Y₂O₃ in ZrO₂ (8YSZ) were used as both solid oxide electrolytes and components of the anode electrode. It was found that the highest electrochemical power output (P_max) was achieved for DC-SOFCs fuelled by biochar from walnut shells, with around 103 mW/cm² obtained for such DC-SOFCs involving 10S1CeZ electrolytes. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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17 pages, 11813 KiB

Open AccessArticle

Study on the Influence and Contribution Rates of Field Aging Factors on Rheological Performance of Bitumen

by Shanglin Song, Yunding Zhu, Zhen Wang, Ziyang Gao, Meng Guo, Jing Huang and Xiaoqiang Jiang

Materials 2025, 18(8), 1775; https://doi.org/10.3390/ma18081775 - 13 Apr 2025

Viewed by 198

Abstract

Laboratory simulation of aging cannot restore the complex aging behavior of bitumen well. The objective of study is to reveal the role of various field aging factors on the aging process of virgin bitumen and SBS(Styrene–Butadiene–Styrene)-modified bitumen. The influence of different field aging [...] Read more.

Laboratory simulation of aging cannot restore the complex aging behavior of bitumen well. The objective of study is to reveal the role of various field aging factors on the aging process of virgin bitumen and SBS(Styrene–Butadiene–Styrene)-modified bitumen. The influence of different field aging factors on aging behavior of virgin bitumen and SBS-modified bitumen were discussed. To achieve this goal, three different field aging styles were used to carry out field aging of virgin bitumen and SBS-modified bitumen. The aging behavior of the two types of bitumen were characterized based on rheological performance, and the influence degree of various aging factors on the rheological performance of bitumen was quantitatively analyzed through the contribution rates. The findings indicated that field aging had an obvious influence on the rheological performance of the two types of bitumen, which showed that the complex modulus, G-R parameter and stiffness modulus increased, and creep rate decreased. The contribution rates significantly indicated the degree of influence of hot oxygen, light and other factors (wind, water, dust, etc.) on the two types of bitumen. Among them, hot oxygen was the main factor leading to the aging of two types of bitumen. The virgin bitumen was not sensitive to aging caused by light, and the aging of SBS-modified bitumen was greatly affected by light. Other field aging factors (wind, water, dust, etc.) led to the aging of virgin bitumen to a certain extent, but inhibited the aging of SBS-modified bitumen. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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13 pages, 1965 KiB

Open AccessArticle

New Biocompatible Cyanoacrylate and Polylactic Acid Hemostatic Patch: An In Vivo Proof of Concept Study

by Alexandru Ilie-Ene, Victor Petru Tosa, Luciana-Madalina Gherman, Raluca Maria Pop, Lorena-Maria Hantig, Catalin Ovidiu Popa and George Calin Dindelegan

Materials 2025, 18(6), 1271; https://doi.org/10.3390/ma18061271 - 13 Mar 2025

Viewed by 418

Abstract

Background: Traumatic injuries cause millions of deaths annually, with intra-abdominal hemorrhage as a leading cause. Achieving hemostasis remains challenging. This study evaluates the hemostatic properties of a novel biocompatible cyanoacrylate–polylactic acid patch. Methods: Thirty-six male Wistar rats were randomized into three groups (control, [...] Read more.

Background: Traumatic injuries cause millions of deaths annually, with intra-abdominal hemorrhage as a leading cause. Achieving hemostasis remains challenging. This study evaluates the hemostatic properties of a novel biocompatible cyanoacrylate–polylactic acid patch. Methods: Thirty-six male Wistar rats were randomized into three groups (control, study, and TachoSil^®) and underwent a standardized liver resection. The hemostasis times were recorded, and blood samples were drawn to assess hemoglobin, hematocrit, and cytokine levels (IL-6 and TNF-α) using validated assays. Results: In the study group, a median time to hemostasis of 94 s was recorded, compared with 256 s for electrocautery (p < 0.001) and 120 s for TachoSil^® (p = 0.010). Hemoglobin levels significantly decreased postoperatively in all groups, with the TachoSil^® group showing the lowest median value (from 15.4 g/dL to 11.9 g/dL, p = 0.006). Furthermore, only the TachoSil^® group exhibited a marked inflammatory response with a significant rise in IL-6 (from 15.6 to 26.8 pg/mL, p = 0.04) and TNF-α (from 9.8 to 28.6 pg/mL, p = 0.01). Conclusions: The results demonstrated that the novel cyanoacrylate–polylactic acid patch achieved rapid hemostasis and was associated with reduced inflammatory responses compared with both electrocautery and TachoSil^®. These findings suggest that this hybrid material may offer a safer and more effective hemostatic alternative. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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14 pages, 1378 KiB

Open AccessArticle

The Quality of the Herbal Product Obtained in the Pressure Agglomeration Process

by Sadowska Urszula, Żabiński Andrzej, Kukiełka Ewelina, Kopeć Aneta and Mudryk Krzysztof

Materials 2025, 18(4), 799; https://doi.org/10.3390/ma18040799 - 12 Feb 2025

Viewed by 537

Abstract

The aim of the conducted research was to evaluate the impact of the pressure agglomeration process of lemon balm (Melissa officinalis L.) on the mechanical properties of the obtained product, its antioxidant capacity, and total polyphenol content. Two fractions of lemon balm [...] Read more.

The aim of the conducted research was to evaluate the impact of the pressure agglomeration process of lemon balm (Melissa officinalis L.) on the mechanical properties of the obtained product, its antioxidant capacity, and total polyphenol content. Two fractions of lemon balm were isolated with particle sizes of 0.5–2.5 mm and 2.5–5.0 mm. The isolated fractions were compacted using a Fritz Heckert EU 20 hydraulic press, applying compaction pressures of 100, 150, and 200 MPa. A closed die was used, with 2 g of the plant sample introduced each time. The mechanical properties of the obtained product were determined through an abrasion test and diameter test (Brazilian method) using the MTS Insight 2 testing machine. The total polyphenol content and antioxidant activity were measured using the ABTS method, both directly after product preparation and after a 6-month storage period. The compaction of lemon balm resulted in an increase in total polyphenol content and antioxidant properties compared to the unpressed raw material. The obtained product displayed favorable mechanical properties, as confirmed by the conducted mechanical tests. Regardless of the applied herb fraction, an agglomeration pressure of 200 MPa is particularly recommended. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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13 pages, 4130 KiB

Open AccessArticle

Multi-Perspective Characterization of a Performance of a Barrel Drill Made of Tungsten Carbide Composite

by Kazimierz Rychlik, Mirosław Bramowicz and Sławomir Kulesza

Materials 2025, 18(4), 794; https://doi.org/10.3390/ma18040794 - 11 Feb 2025

Viewed by 600

Abstract

This paper presents the results of an estimation of the structural and roughness parameters of the outer surface layers of a barrel drill made of cobalt matrix sintered tungsten carbide samples (WC-Co) made by sintering and subjected to finishing by grinding. In order [...] Read more.

This paper presents the results of an estimation of the structural and roughness parameters of the outer surface layers of a barrel drill made of cobalt matrix sintered tungsten carbide samples (WC-Co) made by sintering and subjected to finishing by grinding. In order to evaluate the geometric and functional structure of the surface, profilometric measurements were carried out at different scan lengths. The geometric structure of the studied surfaces was characterized by the roughness parameters Ra, Rq, and Rz, while the functional structure was determined by the reduced profile heights Rpk, Rk, Rvk and the material ratios M_r1 and M_r2 determined by the Abbott-Firestone curves. Multiscale analysis of the dependence of the roughness and functional parameters on the measurement lengths was carried out using the root mean square (RMS) method, from which monofractal structures of the surface profile variations were found. Consistency of the fractal dimensions estimated for the drill bit might be due to its finer finishing. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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21 pages, 5175 KiB

Open AccessArticle

Effect of Undercut Bolt Anchor Depth on Failure Cone Geometry: A Numerical FEM Analysis and Experimental Verification

by Józef Jonak, Andrzej Wójcik, Robert Karpiński and Kamil Jonak

Materials 2025, 18(3), 686; https://doi.org/10.3390/ma18030686 - 4 Feb 2025

Viewed by 644

Abstract

This study examined the influence of the effective embedment depth h_ef of undercut anchors and the diameter of their heads on the formation of the so-called cone failure angle α. Cone failure formation during simulated anchor pull-out tests was analyzed numerically using [...] Read more.

This study examined the influence of the effective embedment depth h_ef of undercut anchors and the diameter of their heads on the formation of the so-called cone failure angle α. Cone failure formation during simulated anchor pull-out tests was analyzed numerically using the Finite Element Method (FEM) with the ABAQUS software and the XFEM algorithm. The analysis was conducted for three sizes of undercut anchor heads and four embedment depths. The numerical analysis results were compared with field test results obtained during pull-out tests of anchors installed in a rock medium (sandstone). Good agreement was observed between the numerical and field test results. The results of the numerical study are highly consistent with those obtained during the field survey. Moreover, they align closely with findings from previous numerical studies conducted by members of the research team, as presented in earlier publications. For the assumed simulation and field test conditions (sedimentary rocks, gray sandstone), no clear correlation was found between the embedment depth or the anchor head diameter and the value of the cone failure angle in the initial phase of the failure zone development. This result contrasts with certain findings reported in the literature. Many existing studies on anchor bolts focus on material properties or load-bearing capacity, but lack an in-depth analysis of how anchor depth influences the geometry of the failure cone. This research addresses that gap, providing valuable insights with practical implications for design codes and safety evaluations. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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15 pages, 3517 KiB

Open AccessArticle

Measurement of Sorption Isotherms to Guide Mixed Display of Archaeological Iron, Bone, and Glass

by David Thickett, Antanas Mėlinis and Bhavesh Shah

Materials 2024, 17(23), 5934; https://doi.org/10.3390/ma17235934 - 4 Dec 2024

Viewed by 670

Abstract

This study examines the preservation challenges of archaeological iron, bone, and glass within shared environments focusing on material-specific degradation mechanisms. The relative humidity (RH) requirements for these materials can vary significantly. Iron presents distinct stability groups at specific RH thresholds, albeit levels below [...] Read more.

This study examines the preservation challenges of archaeological iron, bone, and glass within shared environments focusing on material-specific degradation mechanisms. The relative humidity (RH) requirements for these materials can vary significantly. Iron presents distinct stability groups at specific RH thresholds, albeit levels below 30% RH are recommended for sensitive artefacts. Little is known about the moisture response of bone, and the heterogeneity of the material poses additional challenges for its examination. Glass can undergo deterioration at both high and low RHs due to the threat of aqueous attack and transformation of the pristine glass or the crizzling and delamination of the already transformed glass. Experiments employing dynamic vapour sorption (DVS), acoustic emission (AE), and oxygen depletion analyses provided insights into the moisture response behaviours of these materials. It was found that the deleterious akageneite formation increases dramatically at RHs > 30% in archaeological iron, reinforcing the current guidelines. Bone exhibits significant hygroscopicity as well as isotherm steepening below 25% RH on desorption, suggesting this threshold could be advisable to avoid structural damage. In glass, there is evidence of significant mass fluctuations between c. 60 and 95% RH, as well as isotherm steepening around 30% RH on desorption, thus providing more empirical evidence to published storage recommendations. This work sheds more light on the risk assessment for mixed-material showcases and underscores the necessity of nuanced RH guidelines that consider the material-specific degradation mechanisms. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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9 pages, 1124 KiB

Open AccessArticle

An Assessment of the Strength and Physical Properties of Edible Tableware from Flax Seed and Flaxseed Cake

by Dariusz Andrejko and Agata Blicharz-Kania

Materials 2024, 17(22), 5510; https://doi.org/10.3390/ma17225510 - 12 Nov 2024

Viewed by 961

Abstract

Alternatives to traditional disposable plastic tableware are constantly sought. The aim of the study was to assess the possibility of using oilseeds and their press cakes for the production of edible tableware. Edible vegan plates (P) and bowls (B) were produced. The basic [...] Read more.

Alternatives to traditional disposable plastic tableware are constantly sought. The aim of the study was to assess the possibility of using oilseeds and their press cakes for the production of edible tableware. Edible vegan plates (P) and bowls (B) were produced. The basic ingredients used for production were flax seeds (S) or flax press cake (C). Plates made using press cakes under a pressure of 3 kg deformed to a lesser extent than those containing seeds. However, they were more susceptible to crumbling during shaking. The colour of the tableware made on the basis of flax press cakes was lighter and was characterised by a higher chromaticity in the yellow and red direction. Significantly higher water absorption was characteristic of the tableware in which flax press cakes were used instead of flax seeds. The lowest water absorption (17.14%) after 30 min of soaking was recorded for the PS sample. After the test simulating the use of the tableware, a significant reduction in strength was observed overall (except for the PS test). The panelists rated the consistency and palatability of the PS, BS and PC tests very similarly. The highest overall acceptability was noted for the BS and PC tests. In conclusion, the development of edible bowls and plates made from flax seeds or flaxseed cake is an alternative solution for the production of environmentally friendly tableware. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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14 pages, 6674 KiB

Open AccessArticle

Application of Hybrid Absorptive–Diffusive Panels with Variable Acoustic Characteristics Based on Wooden Overlays Designed Using Third-Degree-of-Freedom Bezier Curves

by Bartlomiej Chojnacki, Kamil Schynol and Klara Chojnacka

Materials 2024, 17(22), 5421; https://doi.org/10.3390/ma17225421 - 6 Nov 2024

Viewed by 873

Abstract

This manuscript describes the application of novel hybrid acoustic panels with variable acoustic properties that could be used in the design process. Despite the significant growth in the modern acoustic absorbing and diffusing panel sector in recent years, there is still a need [...] Read more.

This manuscript describes the application of novel hybrid acoustic panels with variable acoustic properties that could be used in the design process. Despite the significant growth in the modern acoustic absorbing and diffusing panel sector in recent years, there is still a need for sustainable and original designs that will fit standard interior design trends. The most significant requirement is satisfying the design needs of variable acoustic venues. The availability of acoustic panels with variable properties is minimal, as most designs are based on textiles in the form of rolling banners; therefore, there is no market diversity. The current paper presents an original solution for a novel perforated wooden panel based on third-degree-of-freedom curves. Due to the possibility of exchanging the front panel, the acoustic surface can be varied and adjusted to the room considering different requirements for the acoustic climate, for example, by modifying the attenuation range from low to mid–high frequencies. The novel panels have unique esthetic properties with functional acoustic features regarding sound diffusion and absorption. In this paper, sound absorption and diffusion measurements will be presented for the different variants of the panels, presenting the option to modify the parameters to adjust the panel’s features to the room’s needs. In situ acoustic measurements in a laboratory were conducted to test the variable acoustic panels’ influence on the room’s acoustic parameters, such as T30 and C80. In summary, the advantages of this kind of design will be discussed, alongside the possible impact on modern construction materials’ utilization in architecture. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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13 pages, 6819 KiB

Open AccessArticle

Structural and Chemical Analysis of Three Regions of Bamboo (Phyllostachys Edulis)

by Shaohua Gu, Ana Lourenço, Xin Wei, Jorge Gominho, Ge Wang and Haitao Cheng

Materials 2024, 17(20), 5027; https://doi.org/10.3390/ma17205027 - 14 Oct 2024

Cited by 1 | Viewed by 1497

Abstract

This study focuses on three different regions of moso bamboo (Phyllostachys edulis): an inner layer (IB), middle layer (MB), and outer layer (OB), to comprehensively characterize the structural features, chemical composition (ash, extractives and lignin contents), and the lignin monomeric composition as determined [...] Read more.

This study focuses on three different regions of moso bamboo (Phyllostachys edulis): an inner layer (IB), middle layer (MB), and outer layer (OB), to comprehensively characterize the structural features, chemical composition (ash, extractives and lignin contents), and the lignin monomeric composition as determined by analytical pyrolysis. The results show that bamboo presents a gradient structure. From the IB to OB, the vascular bundle density and fiber sheath ratio increase, the porosity decreases (from 45.92% to 18.14%), and the vascular bundle diameter–chord ratio increases (from 0.85 to 1.48). In terms of chemical composition, the ash, extractives, and acid-soluble lignin content gradually decrease from IB to OB. The holocellulose content follows the trend: MB (66.3%) > OB (65.9%) > IB (62.8%), while the acid-insoluble lignin content exhibits the opposite trend: IB (22.6%) > OB (17.8%) > MB (17.7%). Pyrolysis products reveal the diversity of carbohydrates and lignin derivatives, with a lignin monomeric composition rich in syringyl and guaiacyl units and lower amounts of H-units: the IB has an H:G:S relation of 18:26:55, while 15:27:58 is the ratio for the MB and 15:40:45 for the OB; S/G ratio values were, respectively, 1.22, 1.46, and 0.99. A comprehensive analysis highlights significant gradient variations in the structure and chemistry of bamboo, providing robust support for the classification and refinement methods of bamboo residues for potential applications. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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11 pages, 6924 KiB

Open AccessArticle

Preparation of Imidazole Compounds as Latent Curing Agents and Their Application in RGB LED Packaging

by Jiangcong Chen, Shujuan Zhang, Biwen Li, Pinghu Chen and Hengfeng Li

Materials 2024, 17(19), 4935; https://doi.org/10.3390/ma17194935 - 9 Oct 2024

Viewed by 1050

Abstract

LED packaging miniaturization has raised more requirements for LED materials. As a material contacting the LED chip directly, the reliability of LED non-conductive adhesive has also garnered increasing attention. This study optimized the formula for non-conductive adhesives for an imidazole curing system. The [...] Read more.

LED packaging miniaturization has raised more requirements for LED materials. As a material contacting the LED chip directly, the reliability of LED non-conductive adhesive has also garnered increasing attention. This study optimized the formula for non-conductive adhesives for an imidazole curing system. The optimized composition of the adhesive is 25%wt for the curing agent and 30%wt for the silica. The prepared non-conductive adhesive has a 7-day pot life and 9-month storage stability. The shear strength reached 87 g and 72 g at 25 °C and 160 °C, respectively. The reliability of the LED modules packaged with the non-conductive adhesive was researched. The green and blue light intensity change was 4.7%, 43.7%, respectively, indicating good anti-aging properties. The blue light decay was mainly due to adhesive aging. The non-conductive adhesive effectively prevented “caterpillar” growth. This provides useful and practical guidelines for industry for applications of adhesive in different packages. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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20 pages, 3737 KiB

Open AccessArticle

Ammonia-Cyanuric Acid Co-Production in Boiler Denitrification System

by Qingjia Wang, Haowen Wu, Man Zhang, Qiang Song, Nan Hu and Hairui Yang

Materials 2024, 17(19), 4692; https://doi.org/10.3390/ma17194692 - 24 Sep 2024

Cited by 1 | Viewed by 965

Abstract

In response to the issues of poor economic efficiency and high CO₂ emissions in the urea-to-ammonia technology of thermal power plants, this paper innovatively proposes a new ammonia production process for thermal power plants. This process utilizes the waste heat of thermal [...] Read more.

In response to the issues of poor economic efficiency and high CO₂ emissions in the urea-to-ammonia technology of thermal power plants, this paper innovatively proposes a new ammonia production process for thermal power plants. This process utilizes the waste heat of thermal power plant boilers and conducts urea pyrolysis through two-stage heating to prepare ammonia and cyanuric acid. From this, the prepared ammonia can be used in the denitrification process of thermal power plants, and the prepared cyanuric acid can bring additional benefits to thermal power plants. The optimal process scheme was determined through orthogonal experiments of urea pyrolysis. And with the help of Aspen Plus software, a whole-process modeling analysis of urea pyrolysis experiments was carried out to investigate the influences of the melting temperature, melting time, reaction temperature, and reaction time on the process. The results show that when the melting temperature was 160 °C, the melting time was 45 min, the reaction temperature was 240 °C, and the reaction time is 20 min, which was the best scheme, 18.45% ammonia and 52.35% cyanuric acid could be obtained. Through the combined analysis of the Aspen Plus simulation and urea pyrolysis experiments, it was found that the melting temperature should be controlled within 160–167 °C, the melting time should be controlled within 40–45 min, the reaction temperature should be controlled within 240–245 °C, and the reaction time should be controlled within 15–20 min. Compared with the existing urea-to-ammonia process, this process has the advantages of nearly zero emissions and good economic benefits, thus providing reliable research data support for future industrialization. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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25 pages, 12892 KiB

Open AccessArticle

Mechanism of Rock Mass Detachment Using Undercutting Anchors: A Numerical Finite Element Method (FEM) Analysis

by Andrzej Wójcik, Kamil Jonak, Robert Karpiński, Józef Jonak, Marek Kalita and Dariusz Prostański

Materials 2024, 17(18), 4468; https://doi.org/10.3390/ma17184468 - 11 Sep 2024

Cited by 1 | Viewed by 1478

Abstract

Undercutting anchors are structural elements used in construction and geotechnics to stabilize both structures and soils. Their main applications include stabilizing slopes and embankments, reinforcing foundations, and providing support during tunnel construction and other underground works. The authors propose the use of these [...] Read more.

Undercutting anchors are structural elements used in construction and geotechnics to stabilize both structures and soils. Their main applications include stabilizing slopes and embankments, reinforcing foundations, and providing support during tunnel construction and other underground works. The authors propose the use of these anchors in rock mass detachment technology. This article presents a comprehensive analysis of the mechanism behind rock mass detachment using an undercutting anchor. Particular attention is given to the influence of parameters such as the fracture energy of the medium and the coefficient of friction between the medium and the anchor head on the detachment process of rock elements during anchor expansion in the drilled hole. Numerical FEM analysis was employed to model the effect of changes in the shape and size of failure cones under varying simulation conditions. The discussed problem is crucial for evaluating the effectiveness of this anchor design under non-standard conditions, particularly in the unconventional destruction of rock media. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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15 pages, 4640 KiB

Open AccessArticle

Investigation of Releasing Chamomile Essential Oil from Inserts with Cellulose Agar and Microcrystalline Cellulose Agar Films Used in Biotextronics Systems for Lower Urinary Tract Inflammation Treatment

by Emilia Frydrysiak, Krzysztof Śmigielski, Alina Kunicka-Styczyńska and Michał Frydrysiak

Materials 2024, 17(16), 4119; https://doi.org/10.3390/ma17164119 - 20 Aug 2024

Viewed by 1390

Abstract

Lower urinary tract inflammation is a very common problem which occurs particularly in women. That is why the idea of a biotextronics system for preventive and supportive treatment came to be. The system is a kind of a therapeutic clothing in the form [...] Read more.

Lower urinary tract inflammation is a very common problem which occurs particularly in women. That is why the idea of a biotextronics system for preventive and supportive treatment came to be. The system is a kind of a therapeutic clothing in the form of underwear integrated with a four-layer pantiliner with biological active compounds (from chamomile essential oil) immobilized on the insert with a cellulose agar or microcrystalline cellulose agar film. In this research, the outer part of the insert was investigated for its ability to release compounds with antibacterial and anti-inflammatory activity under the temperature of the treatment (40 °C). The research was conducted on the day of the insert preparation (day 0) and also after 7, 14, 28, and 56 days to test the ability of the insert to be stored without changing its properties. The results showed that even after 56 days of storage, there are compounds released that are known to have antibacterial activity, such as α-bisabolol. The system requires further tests involving bacteria; however, chamomile essential oil seems to be good substrate for biotextronics systems for preventive and supportive treatment of lower urinary tract inflammations. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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16 pages, 5769 KiB

Open AccessArticle

Fabrication of Soft Biodegradable Foam with Improved Shrinkage Resistance and Thermal Stability

by Fangwei Tian, Hanyi Huang, Yaozong Li and Wentao Zhai

Materials 2024, 17(15), 3712; https://doi.org/10.3390/ma17153712 - 27 Jul 2024

Cited by 5 | Viewed by 1357

Abstract

The soft PBAT foam shows good flexibility, high elasticity, degradable nature, and it can be used as an environmental-friendly candidate for EVA and PU foams. Unfortunately, there are few reports on the application of PBAT as a soft foam. In this study, PBAT [...] Read more.

The soft PBAT foam shows good flexibility, high elasticity, degradable nature, and it can be used as an environmental-friendly candidate for EVA and PU foams. Unfortunately, there are few reports on the application of PBAT as a soft foam. In this study, PBAT foam was fabricated by a pressure quenching method using CO₂ as the blowing agent. A significant volume shrinkage of about 81% occurred, where the initial PBAT foam had an extremely high expansion ratio, of about 31 times. A 5–10 wt% PBS with high crystallinity was blended, and N₂ with low gas solubility and diffusivity was mixed, with the aim of resisting foam shrinkage and preparing PBAT with a high final expansion ratio of 14.7 times. The possible mechanism behind this phenomenon was established, and the increased matrix modulus and decreased pressure difference within and outside the cell structure were the main reasons for the shrinkage resistance. The properties of PBAT and PBAT/PBS foams with a density of 0.1 g/cm³ were measured, based on the requirements for shoe applications. The 5–10 wt% PBS loading presented advantages in reducing thermal shrinkage at 75 °C/40 min, without compromising the hardness, elasticity, and the compression set, which ensures that PBAT/PBS foams have good prospects for use as soft foams. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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15 pages, 3053 KiB

Open AccessArticle

The Impact of Boron Nitride Additive on Thermal and Thermochromic Properties of Organic Thermochromic Phase Change Materials

by Natalia Paprota, Magdalena Szumera and Kinga Pielichowska

Materials 2024, 17(15), 3632; https://doi.org/10.3390/ma17153632 - 23 Jul 2024

Viewed by 1021

Abstract

Thermochromic phase change materials (TPCMs) are gaining increasing interest among scientists. These multifunctional materials can store thermal energy but also, at the same time, during the phase transition, they can change colour. Thermal conductivity is also extremely important for this type of material, [...] Read more.

Thermochromic phase change materials (TPCMs) are gaining increasing interest among scientists. These multifunctional materials can store thermal energy but also, at the same time, during the phase transition, they can change colour. Thermal conductivity is also extremely important for this type of material, which is why various additives are used for this purpose. This work aimed to study the properties of thermochromic phase change materials with an inorganic modifier. Stearic acid, behenyl alcohol, and bromocresol purple were used as thermochromic system components, while boron nitride particles were used as an additive. The key tests for such systems are thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), which allow determining the thermal stability of the materials (at around 170 °C) and phase transition parameters (thermal energy storage of 300 J/g in the range of 40–75 °C). The thermochromic properties were tested, and satisfactory results were obtained. In the end, laser flash analysis (LFA) tests indicated that boron nitride improves the thermal conductivity of the organic thermochromic phase change material by almost 30%. The results showed that the tested materials have great potential as thermochromic phase change materials for thermal energy storage. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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11 pages, 12125 KiB

Open AccessFeature PaperArticle

Surprising Effects of Ti and Al₂O₃ Coatings on Tribocatalytic Degradation of Organic Dyes by GaN Nanoparticles

by Xi Xu, Chenyue Mao, Jiannan Song, Senhua Ke, Yongming Hu, Wanping Chen and Chunxu Pan

Materials 2024, 17(14), 3487; https://doi.org/10.3390/ma17143487 - 14 Jul 2024

Cited by 6 | Viewed by 1364

Abstract

GaN is more stable than most metal oxide semiconductors for the photocatalytic degradation of organic pollutants in harsh conditions, while its catalytic efficiency has been difficult to be substantially improved. In this study, the tribocatalytic degradation of organic dyes by GaN nanoparticles has [...] Read more.

GaN is more stable than most metal oxide semiconductors for the photocatalytic degradation of organic pollutants in harsh conditions, while its catalytic efficiency has been difficult to be substantially improved. In this study, the tribocatalytic degradation of organic dyes by GaN nanoparticles has been investigated. Stimulated through magnetic stirring using homemade Teflon magnetic rotary disks in glass beakers, the GaN nanoparticles were found to induce negligible degradation in rhodamine B (RhB) and methyl orange (MO) solutions. Surprisingly, the degradation was greatly enhanced in beakers with Ti and Al₂O₃ coatings on their bottoms: 99.2% and 99.8% of the 20 mg/L RhB solutions were degraded in 3 h for the Ti and Al₂O₃ coatings, respectively, and 56% and 60.2% of the 20 mg/L MO solutions were degraded in 24 h for the Ti and Al₂O₃ coatings, respectively. Moreover, the MO molecules were only broken into smaller organic molecules for the Ti coating, while they were completely degraded for the Al₂O₃ coating. These findings are important for the catalytic degradation of organic pollutants by GaN in harsh environments and for achieving a better understanding of tribocatalysis as well. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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19 pages, 2701 KiB

Open AccessArticle

Are Critical Fluctuations Responsible for Glass Formation?

by Szymon Starzonek, Joanna Łoś, Sylwester J. Rzoska, Aleksandra Drozd-Rzoska and Aleš Iglič

Materials 2024, 17(14), 3385; https://doi.org/10.3390/ma17143385 - 9 Jul 2024

Cited by 1 | Viewed by 1030

Abstract

The dynamic heterogeneities occurring just before the transition to the glassy phase have been named as the cause of amorphization in supercooled systems. Numerous studies conducted so far have confirmed this hypothesis, and based on it, a widely accepted solution to the puzzle [...] Read more.

The dynamic heterogeneities occurring just before the transition to the glassy phase have been named as the cause of amorphization in supercooled systems. Numerous studies conducted so far have confirmed this hypothesis, and based on it, a widely accepted solution to the puzzle of glass transition has been developed. This report focuses on verifying the existence of a strong pretransitional anomaly near the glass transition

T_{g}

. For this purpose, supercooled liquid-crystalline systems with a strong rod-like structure were selected. Based on the obtained experimental data, we demonstrate in this article that the previously postulated dynamic heterogeneities exhibit a critical characteristic, meaning a strong pretransitional anomaly can be observed with the described critical exponent

α = 0.5

. Due to this property, it can be concluded that these heterogeneities are critical fluctuations, and consequently, the transition to the glassy state can be described based on the theory of critical phenomena. To measure the pretransitional anomaly near

T_{g}

in supercooled liquid-crystalline systems, broadband dielectric spectroscopy (BDS) and nonlinear dielectric effect (NDE) methods were applied. The exponent

α

provides insight into the nature and intensity of critical fluctuations in the system. A value of

α = 0.5

suggests that the fluctuations become increasingly intense as the system approaches the critical point, contributing to the divergence in specific heat. Understanding the role of critical fluctuations in the glass transition is crucial for innovating and improving a wide range of materials for energy storage, materials design, biomedical applications, food preservation, and environmental sustainability. These advancements can lead to materials with superior properties, optimized manufacturing processes, and applications that meet the demands of modern technology and sustainability challenges. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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Review

Jump to: Research

33 pages, 10261 KiB

Open AccessReview

Theory and Measurement of Heat Transport in Solids: How Rigidity and Spectral Properties Govern Behavior

by Anne M. Hofmeister

Materials 2024, 17(18), 4469; https://doi.org/10.3390/ma17184469 - 11 Sep 2024

Cited by 1 | Viewed by 1951

Abstract

Models of heat transport in solids, being based on idealized elastic collisions of gas molecules, are flawed because heat and mass diffuse independently in solids but together in gas. To better understand heat transfer, an analytical, theoretical approach is combined with data from [...] Read more.

Models of heat transport in solids, being based on idealized elastic collisions of gas molecules, are flawed because heat and mass diffuse independently in solids but together in gas. To better understand heat transfer, an analytical, theoretical approach is combined with data from laser flash analysis, which is the most accurate method available. Dimensional analysis of Fourier’s heat equation shows that thermal diffusivity (D) depends on length-scale, which has been confirmed experimentally for metallic, semiconducting, and electrically insulating solids. A radiative diffusion model reproduces measured thermal conductivity (K = Dρc_P = D × density × specific heat) for thick solids from ~0 to >1200 K using idealized spectra represented by 2–4 parameters. Heat diffusion at laboratory temperatures (conduction) proceeds by absorption and re-emission of infrared light, which explains why heat flows into, through, and out of a material. Because heat added to matter performs work, thermal expansivity is proportional to ρc_P/Young’s modulus (i.e., rigidity or strength), which is confirmed experimentally over wide temperature ranges. Greater uptake of applied heat (e.g., c_P generally increasing with T or at certain phase transitions) reduces the amount of heat that can flow through the solid, but because K = Dρc_P, the rate (D) must decrease to compensate. Laser flash analysis data confirm this proposal. Transport properties thus depend on heat uptake, which is controlled by the interaction of light with the material under the conditions of interest. This new finding supports a radiative diffusion mechanism for heat transport and explains behavior from ~0 K to above melting. Full article

(This article belongs to the Special Issue Advances in Materials Science and Engineering—in Celebration of 55th Anniversary of the Faculty of Technical Sciences, Warmia and Mazury University in Olsztyn, Poland)

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