Search Results (223)

In periodic technical inspections (PTIs), evaluating the braking efficiency of light passenger vehicles at their Maximum Authorized Mass (MAM) presents a practical challenge, as bringing laden vehicles to inspection is often unfeasible due to logistical and infrastructure limitations. The fBrake method is proposed to overcome this issue by estimating braking efficiency at MAM based on measurements taken from vehicles in more accessible loading conditions. In this study, the fBrake method is validated by demonstrating the equivalence of its efficiency estimates extrapolated from two distinct configurations: an unladen state near the curb weight and a partially laden condition closer to MAM. Following the UNE 26110 standard (Road vehicles. Criteria for the assessment of the equivalence of braking efficiency test methods in relation to the methods defined in ISO 21069), roller brake tester measurements were used to obtain force data under both conditions. The analysis showed that the extrapolated efficiencies agree within combined uncertainty limits, with normalized errors below 1 in all segments tested. Confidence intervals were reduced by up to 74% after electronics update. These results confirm the reliability of the fBrake method for M1 and N1 vehicles and support its adoption as an equivalent procedure in compliance with UNE 26110, particularly when fully laden testing is impractical. Full article

Three-dimensional (3D) printing has emerged as a transformative technology in dental splint fabrication, offering significant advancements in customization, production speed, material efficiency, and patient comfort. This comprehensive review synthesizes the current literature on the clinical use, benefits, limitations, and future directions of 3D-printed dental splints across various disciplines, including prosthodontics, orthodontics, oral surgery, and restorative dentistry. Key 3D printing technologies such as stereolithography (SLA), digital light processing (DLP), and material jetting are discussed, along with the properties of contemporary photopolymer resins used in splint fabrication. Evidence indicates that while 3D-printed splints generally meet ISO standards for flexural strength and wear resistance, their mechanical properties are often 15–30% lower than those of heat-cured PMMA in head-to-head tests (flexural strength range 50–100 MPa vs. PMMA 100–130 MPa), and study-to-study variability is high. Some reports even show significantly reduced hardness and fatigue resistance in certain resins, underscoring material-specific heterogeneity. Clinical applications reviewed include occlusal stabilization for bruxism and temporomandibular disorders, surgical wafers for orthognathic procedures, orthodontic retainers, and endodontic guides. While current limitations include material aging, post-processing complexity, and variability in long-term outcomes, ongoing innovations—such as flexible resins, multi-material printing, and AI-driven design—hold promise for broader adoption. The review concludes with evidence-based clinical recommendations and identifies critical research gaps, particularly regarding long-term durability, pediatric applications, and quality control standards. This review supports the growing role of 3D printing as an efficient and versatile tool for delivering high-quality splint therapy in modern dental practice. Full article

Background and Objectives: This in vitro trial aimed to investigate if there is a correlation between the homogeneities of different composite materials and their adhesion to glass fiber posts (GFPs). Materials and Methods: Twenty intact human upper jaw central incisors extracted due to periodontal diseases were selected for this trial. Endodontic treatment was performed according to ISO recommendations. A total of 4 mm of guttapercha was left in the apical region. Canals were prepared for post insertion. Teeth were randomly allocated into the two following groups depending on the core restorative material (n = 10): I—cores build up with light cured composite; II—cores build up with dual cured composite resin. GFPs were inserted and cores were rebuilt with different composite resins. Longitudinal cuts were made across the axis of the teeth and examined under a scanning electron microscope (SEM). Statistical analysis was accomplished using Mann–Whitney U and Spearman tests (p < 0.05). Results: In the group where the number and size of pores at the interface of GFPs were analyzed, pores were found only in the specimens restored with the light-cured “bulk-filled” composite. In the group where the number and size of pores in the core material were analyzed, pores were found in specimens restored with both the light-cured “bulk-filled” composite and dual-cured resin composite. However, the dual-cured resin composite yielded better results in terms of core integration. Conclusions: There is no statistically significant correlation between the homogeneities of different composite materials and their adhesion to GFP. Full article

The development of high-impact denture base formulations that are suitable for digital light processing (DLP) 3D printing is demanding. Indeed, a combination of high flexural strength/modulus and high fracture toughness is required. In this contribution, eight urethane macromonomers (UMs1-8) were synthesized in a one-pot, two-step procedure. Several rigid diols were first reacted with two equivalents of trimethylhexamethylene diisocyanate. The resulting diisocyanates were subsequently end-capped with a free-radically polymerizable monomer bearing a hydroxy group. UMs1-8 were combined with the monofunctional monomer (octahydro-4,7-methano-1H-indenyl)methyl acrylate and a poly(ε-caprolactone)-polydimethylsiloxane-poly(ε-caprolactone) (PCL-PDMS-PCL) triblock copolymer (BCP1) as a toughening agent. The double-bond conversion, glass transition temperature (T_g), and mechanical properties (flexural strength/modulus, fracture toughness) of corresponding light-cured materials were measured (cured in a mold using a light-curing unit). The results showed that the incorporation of BCP1 was highly efficient at significantly increasing the fracture toughness, as long as the obtained networks exhibited a low crosslink density. The structure of the urethane macromonomer (nature of the rigid group in the spacer; nature and number of polymerizable groups) was demonstrated to be crucial to reach the desired properties (balance between flexural strength/modulus and fracture toughness). Amongst the evaluated macromonomers, UM1 and UM2 were particularly promising. By correctly adjusting the BCP1 content, light-cured formulations based on those two urethane dimethacrylates were able to fulfill ISO20795-1:2013 standard requirements regarding high-impact materials. These formulations are therefore suitable for the development of 3D printable high-impact denture bases. Full article

The aviation sector significantly contributes to environmental challenges, including global warming and greenhouse gas emissions, due to its reliance on fossil fuels. Fuel cells present a viable alternative to conventional propulsion systems. In the context of light aircraft applications, proton exchange membrane fuel cells (PEMFCs) have recently attracted growing interest as a substitute for internal combustion engines (ICEs). However, their performance is highly sensitive to altitude variations, primarily due to limitations in compressor efficiency and instability in cathode pressure. To address these challenges, this research presents a comprehensive numerical model that couples a PEMFC system with a dynamic air compressor model under altitude-dependent conditions ranging from 0 to 3000 m. Iso-efficiency lines were integrated into the compressor map to evaluate its behavior across varying environmental parameters. The study examines key fuel cell stack characteristics, including voltage, current, and net power output. The results indicate that, as altitude increases, ambient pressure and air density decrease, causing the compressor to work harder to maintain the required compression ratio at the cathode of the fuel cell module. This research provides a detailed prediction of compressor efficiency trends by implementing iso-efficiency lines into the compressor map, contributing to sustainable aviation and aligning with global goals for low-emission energy systems by supporting cleaner propulsion technologies for lightweight aircraft. Full article

Traditional hazard identification techniques for Vibrio parahaemolyticus often neglect the distinction between viable and nonviable bacteria in aquatic products, leading to overestimated disease risks and uncertainties in risk assessments. To address this limitation, we developed an automated PMA pretreatment instrument that integrates dark incubation and photo-crosslinking into a unified workflow, allowing customizable parameters such as incubation time, light exposure duration, and mixing speed while maintaining stable temperatures (<±1 °C fluctuation) to preserve bacterial DNA integrity. Leveraging this system, a duplex qPCR assay was optimized for simultaneous quantitative detection of V. parahaemolyticus and V. cholerae in aquatic products and environmental samples. The assay demonstrated robust performance with 90–110% amplification efficiencies across diverse matrices, achieving low limits of detection (LODs) of 10¹–10² CFU/mL in shrimp farming environment water and 10²–10³ CFU/g in shrimp (Litopenaeus vannamei) and oyster (Crassostrea gigas). Notably, it effectively discriminated viable bacteria from 10⁶ CFU/mL(g) nonviable cells and showed strong correlation with ISO-standard methods in real-world sample validation. This integrated platform offers a rapid, automated solution for accurate viable bacterial quantification, with significant implications for food safety, pathogen surveillance, and risk management in aquatic industries. Full article

This study quantitatively evaluates the impact of motion blur—caused by high-speed movement—on image quality in a mobile tunnel scanning system (MTSS). To simulate movement at speeds of up to 70 km/h, a high-speed translational motion panel was developed. Images were captured under conditions compliant with the ISO 12233 international standard, and image quality was assessed using two metrics: blurred edge width (BEW) and the spatial frequency response at 50% contrast (MTF50). Experiments were conducted under varying shutter speeds, lighting conditions (15,000 lx and 40,000 lx), and motion speeds. The results demonstrated that increased motion speed increased BEW and decreased MTF50, indicating greater blur intensity and reduced image sharpness. Two-way analysis of variance and t-tests confirmed that shutter and motion speed significantly affected image quality. Although higher illumination levels partially improved, they also occasionally led to reduced sharpness. Field validation using MTSS in actual tunnel environments demonstrated that BEW and MTF50 effectively captured blur variations by scanning direction. This study proposes BEW and MTF50 as reliable indicators for quantitatively evaluating motion blur in tunnel inspection imagery and suggests their potential to optimize MTSS operation and improve the accuracy of automated defect detection. Full article

Dental researchers and manufacturers use the ISO 4049 standard to determine the depth of cure (DoC) of resin-based composites (RBCs). This standard uses a 4 mm diameter stainless-steel mold and subsequently divides the length of the remaining hard RBC by 2. However, the DoC values obtained using this mold have been challenged. Six bulk-fill RBCs (Tetric plus Fill, Tetric plus Flow, Tetric PowerFill, Tetric PowerFlow, Filtek One, and Aura Bulk Fill) were used to investigate the limitations of the 4 mm diameter mold used in the ISO 4049 standard when compared to a 6 mm diameter metal mold that represented the dimensions of a large cavity in a tooth. Two distinct light curing units were used. One light (Elipar S10) emitted a single peak wavelength of light, while the other (Bluephase G4) was a broad-spectrum, multiple-peak curing light. After 10 s of photocuring, the uncured RBC was immediately removed using acetone. The maximum length of the hard RBC remaining was measured and divided by two so that the effect of these two mold diameters on the DoC results could be compared. The DoC of all six RBCs tested was consistently greater in the 6 mm diameter mold (p < 0.0001). Sectioning revealed that the solvent-dissolved specimens had a clear internal boundary between the apparently well-cured RBC and a peripheral, solvent-resistant, “frosty” region. Using a 4 mm diameter stainless-steel mold resulted in a reduced depth of cure values compared to those obtained when the 6 mm diameter mold was used. The use of a broad-spectrum, multiple-peak LED curing light proved unnecessary for photocuring the six RBCs used in this study. Full article

(1) Background: In order to conduct in vitro studies regarding muco-supported dentures, it is necessary to have a simulation model that simulates the oral mucosa, as it is the main influencing factor for their retention and stabilisation. The aim of this study is to perform tensile and wettability tests in three different elastomers to identify the best material for simulating the oral mucosa. (2) Methods: A tensile test was performed according to ISO 527-1 and a compressive test was performed according to ISO 604:2002, at a constant speed of 10 mm/min. The E-modulus was calculated. A wettability test was performed according to ISO 19403-2. Shore A hardness was measured according to ISO 868:2003. All values were compared with the oral mucosa data. (3) Results: Tensile E-modulus calculation revealed no significant difference between Molloplast^® B and EXA’lence^TM Light Body. The mean drop angle calculation revealed no significant difference between Ufi Gel^® SC and Molloplast^® B. The compression E-modulus showed significant differences for Ufi Gel^® SC and EXA’lence^TM Light Body, while Molloplast^® B showed no significant deviation. Ufi Gel^® SC has a similar Shore A hardness to the other materials. (4) Conclusions: Molloplast^® B and Ufi Gel^® SC are the most similar elastomers to the alveolar mucosa. Full article

The hydrogen fuel quality is critical to the efficiency and longevity of fuel cell electric vehicles (FCEVs), with ISO 14687:2019 grade D establishing stringent impurity limits. This study compared two different sampling techniques for assessing the hydrogen fuel quality, focusing on the National Physical Laboratory hydrogen direct sampling apparatus (NPL DirSAM) from a 35 MPa heavy-duty (HD) dispenser and qualitizer sampling from a 70 MPa light-duty (LD) nozzle, both of which were deployed on the same day at a local hydrogen refuelling station (HRS). The collected samples were analysed as per the ISO 14687:2019 contaminants using the NPL H₂-quality laboratory. The NPL DirSAM was able to sample an HD HRS, demonstrating the ability to realise such sampling on an HD nozzle. The comparison of the LD (H₂ Qualitizer sampling) and HD (NPL DirSAM) devices showed good agreement but significant variation, especially for sulphur compounds, non-methane hydrocarbons and carbon dioxide. These variations may be related to the HRS difference between the LD and HD devices (e.g., flow path, refuelling conditions and precooling for light duty versus no precooling for heavy duty). Further study of HD and LD H₂ fuel at HRSs is needed for a better understanding. Full article

This study explores the synthesis of photocurable non-isocyanate polyhydroxyethylurethanes (BPHUs) derived from renewable sources, designed for biomedical applications and the development towards advanced light curing processes. The following two pathways were developed: an aliphatic route using 1,4-butanediol-derived cyclic carbonates and an aromatic route with resorcinol-based carbonates. Ring-opening polymerization with dodecanediamine produced BPHU intermediates, which were methacrylated to form photoreactive derivatives (aliphatic MAs and aromatic MAs). Comprehensive characterization, including NMR, GPC, and FTIR, confirmed the successful synthesis. The UV curing of these methacrylated compounds yielded hydrogels with swelling properties. Aliphatic BPHUs achieved a gel content of 91.3% and a swelling of 1057%, demonstrating the flexibility and UV stability suitable for adaptable biomedical applications. Conversely, aromatic BPHUs displayed a gel content of 78.1% and a swelling of 3304%, indicating higher rigidity, which is advantageous for load-bearing uses. Cytotoxicity assessments adhering to the DIN EN ISO 10993-5 standard demonstrated non-cytotoxicity, with an >80% cell viability for both variants. This research underscores the potential of green chemistry in crafting biocompatible, versatile BPHUs, paving the way for eco-friendly materials in implantable medical devices. Full article

β-glucans from filamentous fungi are important for human health. There is limited research on polysaccharides from filamentous fungi, and no reports have been published regarding the optimization of culture media to produce β-glucans from Rhizopus oryzae using liquid waste from potato starch processing. In this regard, the fermentation conditions to produce β-glucans from Rhizopus oryzae M10A1 were optimized using the one variable at a time (OVAT) and response surface methodology (RSM). The β-glucans were chemically characterized by determining moisture, nitrogen, protein, fat, ash, and total carbohydrates. The color, molecular weight, β-glucan content, monosaccharide composition, and structural and conformational characteristics were assessed by colorimetry, gel permeation chromatography, high-performance liquid chromatography, and Fourier transform infrared spectroscopy, respectively. The microbial indicators, mesophilic aerobes, molds, yeasts, and Escherichia coli were quantified following ISO standard protocols. Optimization indicated that supplementation with 0.8% (w/v) glucose and ammonium sulfate enhanced heteroglycan production (3254.56 mg/100 g of biomass). The β-glucans exhibited high purity, a light brown color, a molecular weight of 450 kDa, and a composition predominantly consisting of glucose and galactose. These findings suggest that β-glucans from Rhizopus oryzae M10A1 could be used for food and health applications. Full article

The aim of this study was to assess the mechanical properties of experimental flow composites incorporating remineralizing and bactericidal fillers (hydroxyapatite (HAp), calcium fluoride, and nanosilver). The evaluated properties included wear resistance, dynamic properties (impact strength), hardness, and static strength (compressive and bending strength). This work includes SEM analysis. The specimens were prepared using a commercial light-cured composite material based on bisphenol A-glycidyl dimethacrylate (Bis-GMA) (Arkona Flow Art, Niemce, Poland) and composite material modified by adding 2 wt%, 5 wt% of hydroxyapatite powder containing fluoride (calcium fluoride), and nanosilver. For this purpose, hydroxyapatite (HAp) with a grain size of 30 μm, which was previously synthesized using the wet method, was used. The results were evaluated against the ISO 4049 standard. The results were subjected to statistical analysis using IBM SPSS Statistics, version 29 (IBM Corp., Armonk, NY, USA). A significance level of 5% (α = 0.05) was established. Based on the hardness measurements obtained in this study, it can be concluded that the incorporation of hydroxyapatite, calcium fluoride, and nanosilver fillers increased the hardness of the flowable composites (89 ShD). The results revealed that incorporating fillers such as hydroxyapatite, nanosilver, and calcium fluoride led to a decrease in the impact strength of the material (0.095 J/cm²). The results of the compressive strength tests revealed that the flowable composite containing 2 wt% of HAp, F, and Ag exhibited the highest compressive strength (190 MPa) among all of the tested materials. Among the experimental composites, the highest bending strength was observed in the variant containing 2 wt% of HAp, F, and Ag, with a value of 76.48 MPa. Significantly higher wear was observed for the composite containing nanosilver filler (4.02 × 10⁻⁴ Mm³/Nm) compared to the other composites. However, the inclusion of nanosilver as a filler in the composite matrix was found to significantly deteriorate the mechanical properties of the material. Full article

Ethnographic sources from Finland and Estonia in the 18th to early 20th centuries often mention alder bark as a dye source. The bark of grey alder (Alnus incana) and black alder (Alnus glutinosa) was used to dye wool and linen yarns reddish, paint leather red, and darken linen fishing nets. These recipes were simple folk craft and are not represented in dye books. Combining various sources, a selection of ethnographic and historical recipes was reconstructed through dyeing experiments to deepen the knowledge of alder bark dyeing practices and to recreate a colour palette based on past recipes. To understand the properties of the alder bark dye, the dyed textile samples were tested according to the ISO standards for washing, rubbing, and light fastness, and colour was recorded with the CIELab values. Our results show that it was possible to obtain different shades of brown, reddish brown, and dark brown. The colour fastness of dyed wool samples was moderate or good. Slight colour changes in the washed samples compared to the untreated ones were observed, which can be due to the standard’s heavily alkaline detergent. Full article

A framework to include life cycle assessment (LCA) in the importance assessment of quality, safety and environmental (QSE) aspects of a management system has been studied to improve the sustainable development performance in the environmental, social and economic dimensions. But there is a literature gap where impact assessment is a critical factor. This research follows a mixed-methods approach, including a survey of 127 Moroccan companies to assess the adoption and impact of LCA integration. The survey’s findings show that 40% of companies have integrated LCA through significant advances in operational quality, regulatory compliance and sustainability performance. The findings also demonstrate how integration has enhanced long-term strategic decision-making, process optimization and environmental impact assessment. The proposed model aligns the requirements of sustainable LCA standards (ISO 14040/44, ISO 26000 and ISO 15686-5) with certifiable standards (ISO 14001, ISO 9001 and ISO 45001), addresses the opportunities and limitations of organizations during integration, and includes indicators for sustainability analysis. The study highlights how implementing LCA in QSE management creates a systematic approach to sustainability, particularly in terms of employee training, regular performance monitoring and regulatory compliance. In light of changing laws and industry norms, these findings provide a means for sectors to enhance their sustainability performance. Full article