Types Of Materials Research Articles

Analyzing Process Types in Nigerian Newspapers Political Headlines Using Systemic Functional Linguistics (SFL) Transitivity Approach

Purpose: This study aims to examine the use of process types in Nigerian political headlines using the transitivity approach within the framework of Systemic Functional Linguistics (SFL). The purpose of the research is to understand how language is used to construct political narratives in Nigerian newspapers, focusing on the different process types—material, mental, relational, verbal, behavioral, and existential—that shape public perception of political events and actors. Methodology: The study adopts a qualitative method, analyzing 50 political headlines from five major Nigerian newspapers: Vanguard, Leadership News, Punch, Daily Trust, and The Guardian Nigeria. The headlines, selected from articles published between January 2024 and September 2024, are categorized and analyzed based on Halliday's transitivity framework. Findings: The findings reveal that material processes are the most frequently used, representing 48% of the headlines, followed by mental (32%), verbal (20%), and relational processes (10%). Existential and behavioral processes were minimally represented. These results suggest that political discourse in Nigeria is predominantly action- and belief-oriented, with a focus on tangible actions and the intentions of political figures. Unique Contribution to Theory, Practice and Policy: This study makes a unique contribution to theory by applying the SFL transitivity framework to Nigerian political headlines, expanding the understanding of how process types reflect political actions, intentions, and relationships. The findings have practical implications for media practitioners and politicians in crafting messages that effectively engage the public, emphasizing actions and beliefs to influence perception. From a policy perspective, the study suggests the need for greater media literacy to enable the public to critically assess political communication and its impact on public discourse.

The influence of weathering and pedogenesis on the geochemical record of Miocene marls and Plio-Quaternary sediments, Medvednica Mt., Croatia

The geochemical signature of weathering and pedogenesis in a temperate humid climate on two parent material types in the foothills of Medvednica Mt. was studied. Five soil profiles on Miocene marls and three sections of Plio-Quaternary (PlQ) proluvial sediments with overlying soil and weathered material were analyzed. The (clay) mineralogy of all profiles and sections had been determined in previous studies. The chemical composition of the samples was determined by inductively coupled plasma emission spectroscopy (ICP-OES) and inductively coupled plasma mass spectroscopy (ICP-MS). Poorly ordered Fe and Mn oxides were determined in the PlQ sediment and overlying soil samples by atomic absorption spectroscopy (AAS), after oxalate dissolution in the dark. The concentrations and element ratios were used to determine element enrichment/mobility and intensity of chemical weathering, material provenance, and to compare the geochemical signatures with previously obtained clay mineralogy results. Trace elements in the Miocene marls, including rare earth elements (REE), indicate the continental origin of the marl siliciclastic component, while more scattered geochemical data of the PlQ sediments reflect their proluvial/torrential nature. The mass transfer coefficient (τ) for major elements and element ratios of the Miocene marl profiles indicate chemical weathering and pedogenesis of lower intensity. The geochemistry of these samples shows homogeneity within the profiles. In the geochemical signature of the PlQ sections, a chaotic proluvial deposition of the material is visible, as well as the heterogeneity with the overlying soil and weathered material. Overall, the geochemistry results largely support the clay mineralogy of the samples and demonstrate how a multiproxy approach can help test hypotheses about past environments and provide valuable additional information for complex paleoenvironmental studies.

Development of a deep learning-based object recognition system for pre-stage separation to improve the recycling rate of major general-purpose plastics

ABSTRACT The generation of plastic waste has been increasing annually, necessitating various recycling methods. Among these, material recycling with low carbon emissions should be prioritized. This study aims to enhance the material recycling rate by developing a separation system using deep learning-based object recognition. To improve labeling efficiency, image data were acquired for each material type, and the performance of different labeling methods was evaluated. The average precision (AP) values for the single-material learning model using hybrid labeling (manual + automatic) were 0.947 for PET, 0.951 for PP, 0.892 for PE, and 0.896 for PS, demonstrating superior performance compared to other methods. An integrated learning model was also developed for composite materials, achieving AP values of 0.972 for PET, 0.976 for PP, 0.963 for PE, and 0.961 for PS. These results demonstrate the model’s strong applicability for plastic waste recognition.

Bond strength of resin-based restorative materials to fast-setting calcium silicate cement using different resin adhesive systems.

This study assessed the bond strength of resin-based restorative materials to fast-setting calcium silicate cement (Aarhus Uinversity, Denmark) when treated with each of two one-bottle universal adhesive systems. The cement surface (N=256) was treated with a self-priming adhesive and a self-etch phosphate monomer-containing adhesive with and without etching of the cement surface. Specimens then received either resin composite or compomer restorative materials (n=32). The bond strength was measured after 1 day and 1500 thermocycles (n=16). The failure type was visually inspected. The cement-adhesive-restorative material interface was visualized using scanning electron microscopy (SEM). The data were analyzed using multiple linear regression. Restorative material type, resin adhesive system, and thermocycling had a statistically significant effect on the bond strength. Compomer restorative material and self-etch universal adhesive system demonstrated statistically significantly higher bond strength values to fast-setting calcium silicate cement, predominantly exhibiting cement cohesive failure. Etching the cement surface enhanced the bond strength of the self-priming universal adhesive. Thermocycling significantly reduced the bond strength. SEM showed self-etch universal adhesive seemingly diffused over the etched cement surface compared to other groups. Self-etch phosphate monomer-containing universal adhesive and compomer resulted in the highest bond strength to fast-setting calcium silicate cement.

Development and Characterization of Thermal Protection Gels for Steel Pipelines Transporting Combustible Materials

Due to low costs, pipelines are commonly used for transporting hazardous substances such as combustible liquids and gasses. Currently, chemical industrial parks and gas production stations have dense pipeline networks. In the case of a pipeline leakage and subsequent fire accident, the adjacent pipelines could be directly impinged by the flame or engulfed in hot smoke, with the potential to result in a chain of accidents and catastrophic consequences. It is thus of practical importance to develop an efficient thermal protection material for pipelines. In this study, a new type of bio-based gel material was prepared for pipeline thermal protection, using guar gum (GG) as the gelling agent, sodium tetraborate (B) as the crosslinking agent and magnesium chloride (MgCl2) as the fire retardant. Firstly, orthogonal experiments were conducted to examine the gelling time of the gel and determine the optimal formulations that meet the protection requirements. Subsequently, water retention, thermal stability and the microstructure of these formulations were analyzed. Finally, the thermal protection performance of the gel formulations was evaluated under the direct impingement of flames or high-temperature smoke. The results indicated that the best performance was achieved by the formulation with GG, B and MgCl2 mass fractions of 2.5, 0.6 and 0.5 wt%, respectively. This formulation also exhibited the best water retention capacity and thermal stability. In the pipeline thermal protection experiments, this formulation achieved effective protection times of 216 s (for a 90 mm diameter) and 312 s (for a 120 mm diameter) for the lower part of the pipeline under direct flame impingement. Under high-temperature smoke impingement, this formulation also showed excellent performance. These research and findings can provide an important foundation for the further development of thermal protection materials for pipelines under fire conditions.

Improvement of Mro Material Procurement Efficiency Through the Six Sigma Concept at PT Krakatau Steel (Persero) TBK

PT Krakatau Steel (Persero) Tbk (PTKS) is a State-Owned Enterprise engaged in the production of steel and related services. The MRO Procurement Department is a procurement function to process MRO Material purchasing at PTKS. The main problem currently faced is the lead time for the MRO material procurement process which takes a long time, the reason is that procurement is often conducted by spot method and repeatedly for the same material. Too long lead times pose a risk to the smooth production process due to the unavailability of MRO materials when needed. Referring to the MRO Procurement Department's KPI, >85% of the number of POs (Purchase Orders) issued must have a lead time of <41 days, however, based on the actual historical data for 2022, the PO lead time achievement for the MRO material procurement process does not meet the target. Department's KPI, >85% of the number of PO’s (Purchase Orders) issued must have a lead time of <41 days, however, based on the actual historical data for 2022, the PO lead time achievement for the MRO material procurement process does not reach the target. An alternative solution used to speed up procurement lead times is implementing a Blanket Purchase Agreement (BPA) and/or Consignment Contract for MRO routine/consumable material types. The results obtained are that the long and complicated MRO material procurement process for the same type of material can be eliminated, which means that with the improvements made, the MRO Procurement Department can implement a more efficient procurement process.

The epicaridium larvae of Paragigantione species (Isopoda: Epicaridea: Bopyridae) have external yolk sacs: transfer of the genus to Pleurocryptellinae, description of two new species in the genus and a new species of hyperparasite (Isopoda: Epicaridea: Cabiropidae)

The epicaridean isopods previously known to have epicaridium larvae with posterior yolk sacs were species of Pleurocryptella Bonnier, 1900 and a new subfamily, Pleurocryptellinae, was recently erected for this genus. Epicaridium larvae bearing posterior yolk sacs are newly reported from two species of the genus Paragigantione Barnard, 1920 which is transferred from Pseudioninae to Pleurocryptelline on the basis of this and other shared characters of adult males and females with species of Pleurocryptella. Two new species of Paragigantione are described, one from the northeast Atlantic based on type material that was misidentified as belonging to the type species of the genus, P. papillosa Barnard, 1920 and a second from off New Zealand. One specimen of the New Zealand species had a cryptoniscus larva of a new species of hyperparasite of the genus Bourdonia Rybakov, 1990 in the marsupium while another had a species of Duplorbis (Rhizocephala); the former is described based on this material as well as a specimen from a specimen of Pseudione cf. fibriata Richardson, 1910 from New Zealand. Keys to species of Paragigantione for both males and females are provided.

EXPERIENCE IN THE APPLICATION OF METHODS OF RESTORATION OF DAMAGED REINFORCED CONCRETE STRUCTURES IN TRANSPORT CONSTRUCTION

Evidence suggests that concrete self-healing can be achieved by introducing bacteria into the concrete matrix. Despite the fact that a number of researchers have conducted experiments with different types of bacteria, the ideal combination of factors such as bacterial species, types of mineral substrate, types of carrier materials and the amount of each of these components has yet to be identified to make a qualitative breakthrough in solving the problem of self-healing concrete and reinforced concrete structures. The paper presents the results of a study on the development of a technology for obtaining materials with bio-additives, the study of the process of crack repair in concrete, and the establishment of physical and technical properties of concrete modified with a microbiological additive and restored materials. The article analyses the processes of structure formation, physical and mechanical properties of concrete and other cement composites, ways to improve them, degradation processes, damage and defects that reduce the durability of reinforced concrete structures, as well as methods of their repair and restoration. Based on the analysis of existing approaches to the creation of concrete using biotechnology and self-healing processes of defective reinforced concrete structures, theoretical prerequisites for the development of technology for the creation of concrete modified with microbiological additives and self-healing structures are developed. It is concluded that it is potentially possible to heal cracks in concrete under the control of bacteria as a result of mineral sludge formation. However, some areas of this concept require further development. It is necessary to clarify how effectively the deposition of minerals produced by bacteria seals large cracks, i.e. how much the permeability of cracked concrete is reduced to prevent corrosion of embedded reinforcement and thus increase the service life of the building material. In addition, it is necessary to select bacterial species that remain viable when introduced into the concrete matrix for at least the expected service life of the structure. Despite the fact that no qualitative breakthrough has yet been achieved in the field of concrete self-healing, this is a very promising area of research.

The impact of root end filling material type and the application of bone graft on healing of periapical tissues after endodontic microsurgery (a clinical randomized controlled trial)

To evaluate the effect of combining different bioactive root-end filling materials with composite bone graft (xenogeneic mixed with autogenous bone fragments) on the healing process of periapical tissues after endodontic micro-surgery procedure. In this triple-blinded clinical trial, 56 patients were divided into 2 main groups (28 each) according to the root-end filling material and 2 subgroups according to the presence or absence of the composite bone graft material. Group I: MTA root-end filling (n = 28) in which there are Sub-group A: without bone graft (n = 14) and Sub-group B: with composite bone graft (n = 14). Group II: TotalFill root-end filling (n = 28) in which there are Sub-group A: without bone graft (n = 14) and Sub-group B: with composite bone graft (n = 14). Healthy patients whose ages range from 20 to 50 years with small-to-medium size radiolucency in CBCT related to single-rooted maxillary teeth were included in this study. Patients were assigned a number starting from 1 to 56 and were randomly allocated to four test groups (2 main groups and 2 sub-groups) following simple randomization procedure guidelines described by IBM SPSS V23 (IBM USA) statistical analysis software. This trial was triple-blind where the patient, the outcome assessors, and the main operator were blinded to the applied intervention. Every patient was evaluated clinically and by CBCT at two main observation periods: presurgical and 12-month post-operative. They were also examined and evaluated clinically and radiographically through periapical x-rays after one week, three, and six months. Statistical analysis was performed with IBM SPSS Statistics for Windows Version 23.0. Armonk, NY: IBM Corp. Of the 56 patients enrolled in the study, 49 patients were available for the final analysis. All groups showed no statistically significant differences with regard to healing or success rates at the 12-month follow-up mark. No adverse effects were encountered. Results showed that high success rates were achieved using MTA and TotalFill in the healing of periapical lesions after endodontic surgery. The addition of bone graft in small-to-medium size lesions did not affect the success rate of endodontic surgeries.

An appraisal of phase change materials: characteristics, categorization, benefits, drawbacks and utilizations. A review

A new era of energy-efficient solutions has arrived thanks to the revolutionary class of substances known as phase change materials (PCMs), which have the extraordinary capacity to store and release thermal energy during phase transitions. The defining characteristics of PCMs, such as their well-defined melting and freezing temperatures, high latent heat of fusion, and variety of material types, including organic and inorganic PCMs, as well as eutectic combinations, are thoroughly examined in this thoroughly analysis. PCMs are divided into groups according to the physical shape they take and the temperature range in which they are used. These groups include low-temperature variations, high-temperature variants, encapsulated forms, and nanocomposite forms. PCMs provide a wide range of advantages, including effective thermal energy storage, cost-effective energy use, consistent temperature maintenance and small light designs. However, they do have some restrictions, such as compatibility issues and slow heat transfer rates. However, PCMs are used in a wide range of industries, from electronics and renewable energy to building and construction, revolutionizing temperature control, thermal management and energy efficiency. The future of PCM technology offers promise, with ongoing improvements aiming at improving heat transmission, integrating with renewable energy sources and enhancing encapsulation processes. This technology's vital position in a sustainable and efficient energy future is apparent, as it continues to transform our world in the hunt for responsible and green energy solutions.

A hybrid experimental configuration for emissivity measurement at cryogenic temperatures

Abstract In cryogenic and high vacuum systems, radiation mode of heat transfer is the primary source of energy interaction owing to the wide temperature differentials and very low temperatures and pressures. Measurement of radiative properties such as emissivity is crucial in the design of cryogenic systems. Emissivity measurement at cryogenic temperatures requires careful consideration of the sample preparation and measurement conditions to ensure accuracy and reliability. Most experimental techniques developed so far are complex in their design and equipment, and they work only on a single measuring method. To address these challenges, this research has proposed a simpler and hybrid experimental setup that could employ both calorimetric and heat flux methods to directly measure the total hemispherical emissivity in the range 90 K–180 K. Experiments were conducted with five types of materials (black paint, stainless steel, aluminum foil, aluminized mylar foil, and copper sheet) by using both methods, and the results were validated with the literature data. The data obtained by calorimetric and heat flux methods for each sample showed a high level of consistency with each other, with a variation of only ±1.5%. Moreover, the discrepancy between the measured and literature data was within the acceptable range of 0.3%–10%. The total hemispherical emissivity of mechanically treated copper was higher than that of chemically polished copper by 11%. This simplified setup has incorporated all possible means to minimize heat leakages into and from the cryostat while maintaining accuracy. The obtained data can be used to accurately estimate the radiation heat loads in cryopumps and other cryogenic systems that use similar components.

Growth of zinc oxide nanowires by a hot water deposition method.

Recently, various methods have been developed for synthesizing zinc oxide (ZnO) nanostructures, including physical and chemical vapor deposition, as well as wet chemistry. These common methods require either high temperature, high vacuum, or toxic chemicals. In this study, we report the growth of zinc oxide ZnO nanowires by a new hot water deposition (HWD) method on various types of substrates, including copper plates, foams, and meshes, as well as on indium tin oxide (ITO)-coated glasses (ITO/glass). HWD is derived from the hot water treatment (HWT) method, which involves immersing piece(s) of metal and substrate(s) in hot deionized water and does not require any additives or catalysts. Metal acts as the source of metal oxide molecules that migrate in water and deposit on the substrate surface to form metal oxide nanostructures (MONSTRs). The morphological and crystallographic analyses of the source-metals and substrates revealed the presence of uniformly crystalline ZnO nanorods after the HWD. In addition, the growth mechanism of ZnO nanowires using HWD is discussed. This process is simple, inexpensive, low temperature, scalable, and eco-friendly. Moreover, HWD can be used to deposit a large variety of MONSTRs on almost any type of substrate material or geometry.

Data evaluation for identifying meaningful engineering characteristics of the flexible panels used for aerial module for pedological drought

The existing worldwide information related to the aerial modules used for transporting mulching substances is particularly pernicious. Thus, at this moment, on an international level, cargo transport solutions for mulching lands affected by soil drought are limited to identifying the maximum value of the load (1250–4500 kgf), the type of raw material from which it is made (polyamide), the shape (quadratic, octagonal, rectangular) and its dimensions (2.13 m × 3 m for a maximum transport capacity of 1250 kgf – 5.5 m × 5.5 m for a maximum transport capacity of 4500 kgf). Also, among the solutions for protecting lands affected by wildfires, the sowing technique with the help of drones was identified. Thus, the seeded compost balls are allowed to fall by gravity from the drones, being released randomly in the demineralised areas, difficult to reach by land transport. The paper presents the latest research of INCDTP specialists – carried out in the national premiere – regarding the iterative-incremental development of a multi-role collapsible aerial module that has as its theatre of operations the desertified areas (due to the pedological drought) of Romania. The central point of the research is focused on: i) the experimentation in the accredited laboratories of INCDTP, of flexible panels joined by mechanical-textile technology; ii) statistical analysis of values; iii) predicting the minimum values of the physical-mechanical characteristics of the composite material.

Performance optimization of hydrogen storage reactors based on PCM coupled with heat transfer fins or metal foams

Metal hydride is a type of solid hydrogen storage material that offers excellent hydrogen absorption and desorption reaction properties. However, there is a strong thermal effect during the reaction process when the materials are applied in reactors. Thus, effective thermal management techniques are crucial for promoting efficient reactions. Prior studies on the subject have shown that phase change materials can be coupled with metal hydride reactors to transfer the reaction heat. To further enhance the transfer of heat and reaction efficiency of the metal hydride reactors based on phase change materials, this study explored heat transfer enhancement methods on the phase change materials side, including adding heat transfer fins and discussing the fin parameters and composite foam metal. The findings of the study showed that in comparison to the reactor without fins, the absorption rate of adding 10 sets of fins can increase by 28%, and as the number of fins increased to 14, this value could increase to 39.4%. The use of Y-shaped fins did not substantially improve the reaction rate, mainly due to the sufficient number of straight fins, and the heat transfer area reaching the limit of the fin enhanced the process of heat transport. Thus, the improved method of using copper foam is further considered. Compared with the reactor with and without fins, the absorption rate of the copper foam coupled reactor is increased by 23.4% and 61.3%, respectively.

Scanning Acousto-Optoelectric Spectroscopy on a Transition Metal Dichalcogenide Monolayer.

The charge carrier dynamics are investigated by surface acoustic waves (SAWs) inside a WSe2 monolayer on LiNbO3 by scanning acousto-optoelectric spectroscopy. A strong enhancement of the PL emission intensity is observed almost over the entire area of the flake. This enhancement increases with increasing amplitude of the wave and is especially strong at or in the vicinity to defects. The latter is attributed to the SAW-driven Poole-Frenkel activation of trapped charge carriers bound to trapping sites at these defects. In addition, the PL intensity exhibit clear periodic modulations at the SAW's frequencyfSAW and at 2 fSAW. These modulations are clear and unambiguous fingerprints of spatio-temporal carrier dynamics driven by the SAW. These occur on sub-nanosecond timescales which are found in good agreement with calculated exciton dissociation times. Mapping and analyzing both effects, this study shows that scanning acousto-electric spectroscopy provides a highly sensitive and local contact-free probe which uncovers distinct local features not resolved by conventional quasi-static photoluminescence techniques. The method is ideally suited to study carrier transport in 2D and other types of nanoscale materials and to reveal dynamic exciton modulation, and carrier localization and activation dynamics in the technologically important megahertz to gigahertz frequency range.

Sustainability assessment of additive manufacturing end-of-life material management

Additive manufacturing (AM) methods enable complex, customized, and on-demand production of many products from different material types across various industries. The growing demand for flexible and more sustainable manufacturing solutions places AM in the mix of processes considered for non-commodities. However, AM processes also present unintentional environmental releases in end-of-life (EoL) material management, compromising overall sustainability. Data availability to assess the sustainability of individual EoL material management from individual AM processes is limited. Even so, EoL materials generated across AM practices frequently overlap, supporting high-level assessment as an alternative approach. Therefore, a holistic AM EoL material management sustainability analysis was completed using a customized list of efficiency, environmental, energy, and economic indicators from the Gauging Reaction Effectiveness for the Environmental Sustainability of Chemistries with a multi-Objective Process Evaluator (GREENSCOPE) methodology. Subsequently, this assessment identified low material recycling rates and high energy costs in some EoL material management processes, such as incineration and recovery. Subsequently, a trade-off analysis was performed to determine process modification opportunities, including implementing recycling to reduce the amount of hazardous waste at the expense of additional energy and cost investment. The AM EoL-specific sustainability analysis serves as a resource to offer insights and empower policymakers and stakeholders to enhance pollution prevention strategies and optimize the existing EoL material management processes.

Microlearning: Innovative Digital Learning for Various Educational Contexts and Groups

Microlearning brings a number of advantages that make it an attractive tool for education. Short and clear lessons minimize the risk of information overload, promote better understanding of the material, and enable quick and easy retention of information. The relevance of microlearning lies in its ability to respond to current educational needs and trends. Microlearning is considered to be a flexible, effective and innovative approach to learning that can be successfully applied in different learning environments, for different learning content and to different target groups. The aim of the research is to describe the impact of microlearning modules on the level of learning outcomes and perceived effectiveness in different target groups. Our research focuses on examining the effectiveness of microlearning on lower secondary school pupils, secondary school students and librarians. In the context of lower secondary schools, specific microlearning units thematically focused on programming and working in Scratch will be presented. This part of the research was carried out using an experiment and a questionnaire survey. In the experiment, the effectiveness of this type of teaching and digital learning materials was investigated. The experiment was conducted in parallel classes of a lower secondary school, and the participants were pupils aged 11 to 12 years old. The aim of the questionnaire survey was to find out the probands' opinions about microlearning. In the context of secondary schools and learning librarians, we conducted a survey of available materials and microlearning modules. In this paper we will introduce general concepts and strategies, with more detailed descriptions of specific modules to be published later. This paper aims to contribute to the growing awareness of the importance of microlearning as an effective educational tool and highlights its potential in different educational settings, especially lower secondary schools, thus providing useful material and inspiration for educators. The results suggest that the implementation of microlearning in lower secondary school settings has led to improved student learning outcomes.

Kinetics and Mechanism Study of Different Types of Surface‐Imprinted Polymers for CO2 Adsorption

ABSTRACTThe increased level of CO2 in the atmosphere has led to global warming and climate change. To mitigate these problems, solid adsorbents have become attractive materials for capturing excess CO2 in the post‐combustion method. Molecularly imprinted polymer (MIP) can be applied to prepare highly selective adsorbents that could capture CO2 molecules. The MIP was prepared using the surface imprinted polymer technique in this preliminary work. Only two types of support materials were used (graphite and silica gel) to screen the best support material that could enhance the CO2 adsorption capacity of the resulting adsorbent, which was analyzed using a fixed‐bed column reactor. Graphite‐imprinted polymer (GMIP) was found to be a good potential for CO2 adsorption. The Avrami model best described the adsorption system, while the fixed‐bed curve data fit the Yoon–Nelson model well. The semi‐empirical method was used to assess the interaction mechanism of the molecularly imprinted polymer with CO2 during adsorption. This investigation involved testing four different ratios of the template complex to functional monomers. The ratio of 1:4 (CO2:Allylthiourea) demonstrated the highest binding energy, with a higher formation of hydrogen bonds. Film diffusion and intraparticle diffusion were the main rate‐limiting steps that played vital roles at different stages of CO2 adsorption. This preliminary work has enhanced the development of MIP for CO2 adsorption and showcased the integration of computational approaches in tailoring specific MIPs.

Stress relaxation and improved fracture toughness of metal bonding using flexible monolith sheets and an epoxy adhesive

AbstractWhile epoxy resins exhibit excellent mechanical and insulating properties as well as excellent stability against heat and chemicals, epoxy adhesives also have drawbacks such as brittleness and stress concentration. Rubber-based materials are often added to epoxy adhesives to increase toughness, but they are sensitive to heat and moisture, limiting their effectiveness in harsh environments. In this study, we propose a new sheet-type adhesive consisting of a conventional liquid epoxy adhesive and an epoxy monolith sheet with internal continuous pores, using the advantageous properties of the flexibility and toughness of the epoxy monolith to avoid stress concentration. We evaluated the adhesion strength for metal bonding using the sheet-type epoxy adhesives via a lap-shear tensile adhesion test at various temperatures. The total destruction energy was also estimated via a tapered double cantilever beam test. Furthermore, a heat cycle adhesion test was conducted using two types of metallic materials with different coefficients of thermal expansion to elucidate the effect of the monolith sheet on the improvement of interfacial failure induced by stress concentration.

The Use of 3D Model Printing for Acute Planning in Oral and Maxillofacial Traumatology

Introduction Due to the complex anatomy of craniomaxillofacial structures, facial reconstruction following high-impact traumas is extremely challenging. Therefore, this study aimed to evaluate the use of biomodels in the surgical planning of complex fractures and the sequelae in the oromaxillofacial region. Materials and Methods This is a cross-sectional, exploratory, descriptive, and quantitative documentary study. It was conducted at the “Dom Luiz Gonzaga Fernandes” Emergency and Trauma Hospital, in the hinterland of the state of Paraíba, in Brazil, based on cases recorded between November 2021 and November 2022. The research instrument utilized was a self-developed questionnaire. Results No statistically significant correlation was observed between the biomodel acquisition time and the length of hospitalization, with a Spearman's correlation coefficient of r = -0.079. Although the need for adjustment of osteosynthesis material was 50% in cases where acrylonitrile butadiene styrene (ABS) models were used, with p (1) = 0.464, in order to be significantly more faithful, it would require a study with a higher sample size. The average length of surgery, in minutes, was 91.25 ± 28.00. The average cost of the materials used to manufacture the biomodels, in Brazilian reais (R$), was R$122.00 ± R$89.09. Conclusion The use of biomodels in the surgical planning of complex fractures and oromaxillofacial sequelae did not increase the length of hospitalization. The material used for the prototype manufacture suggests a potential influence on its faithfulness. The length of surgery was shorter in interventions that utilized biomodels in the planning phase. It was also noted that the average cost of manufacture varies according to the type of material chosen and the quantity required.