Strength Values Research Articles

Manufacturing of hexagonal cross-section thermoplastic matrix composite parts with automatic filament winding system

Thermoplastic filament winding is a flexible manufacturing method typically used in the production of cylindrical composite structures, allowing for in-situ consolidation without the need for a second consolidation step. The objective of this study is to produce non-cylindrical geometries, typically manufactured using thermoset matrix composites according to the literature, using the thermoplastic filament winding process. For this purpose, glass fiber (GF) reinforced polypropylene (PP) prepreg tapes were used to produce hexagonal cross-section thermoplastic composite parts. The critical process parameters; hot-air heater nozzle temperature, compression roller pressure, the linear speed of mandrel rotation, and corner radius of the mandrel, were determined using the Taguchi experimental design method. The interlaminar shear strength (ILSS) and maximum compressive strength (σmax) values were obtained as 211 MPa and 49.40 MPa as maximum, respectively. ANOVA analysis showed that the corner radius had the most significant impact on ILSS, while mandrel rotation speed and temperature were critical for σmax.

Waste glass as an eco-friendly substitute in plastering mortars: analyzing microstructure, thermal, and mechanical properties

This study investigates waste glass (WG) as an environmentally friendly substitute for natural sand in cement mixtures. Plastering mortars were fabricated by replacing sand with WG at proportions of 10%, 20%, and 30%. X-ray diffraction, Thermogravimetry, Scanning Electron Microscopy, and Energy-dispersive X-ray spectroscopy characterized the mortars. Compressive strength was measured at two ages (7 and 28 days) for WG-containing mortars. Results confirm the suitability of waste glass as a sand replacement in mortars, with the 20% WG sample showing optimal compressive strength, contributing to environmental and economic impact reduction. Thermogravimetric analysis of the 30% WG mortar shows a significant difference in mass loss percentages compared to the reference mortar, losing only 3.65% at 28 days versus 7.85%. Additionally, waste glass increased mortar density, reducing porosity and enhancing structural uniformity. Despite a decrease in compressive strength values, the results remain satisfactory for application in the Civil Construction industry. This comprehensive exploration underscores the potential of waste glass as a sustainable alternative, emphasizing its positive effects on both performance and environmental considerations.

De Novo Design and Characterization of Amphiphilic Peptides with Basic Side Chains for Tailored Interfacial Chemistries.

Lysine-leucine (LK) peptides have been used as model systems and platforms for 2D material design for decades. LK peptides are amphiphilic sequences designed to bind and fold at hydrophobic surfaces through hydrophobic leucine side chains and hydrophilic lysine side chains extending into the aqueous subphase. The hydrophobic periodicity of the sequence dictates the secondary structure at the interface. This robust design makes them ideal candidates for controlling interfacial chemistry. This study presents the de novo design and characterization of two novel peptides: LRα14 and LHα14, which substitute lysine with arginine and histidine, respectively, in the helical LKα14 sequence. This modification is intended to expand the LK peptide platform to a new basic interfacial chemistry. We explore the stability of the new LRα14 and LHα14 designs with respect to changes in pH and salt concentration in bulk solution and at the interface using circular dichroism (UV-CD) and vibrational sum-frequency generation spectroscopy, respectively. Notably, the structural stability of the peptides remains unaffected across a wide range of pH and ionic strength values. At the same time, the variation of side-chain chemistry leads to a wide spectrum of interfacial water structures. By extension of the LK platform to include arginine and histidine, this study broadens the toolbox for designing tailored interfacial chemistries with applications in material and biomedical sciences.

Evaluation of high-volume fly-ash cementitious binders incorporating nanosilica as eco-friendly sustainable concrete repair materials

Nowadays, the use of environmentally friendly, long-lasting building materials with minimal energy and carbon dioxide emissions are highly recommended. Some of these materials can be made from industrial and agricultural wastes. By replacing ordinary Portland cement (OPC) with large volume of fly ash waste (FA), environmental issues associated with landfill disposal and cement manufacture can be mitigated. Nonetheless, using a high amount of FA (up to 50 %) to replace cement resulted in poor strength performance, particularly during early age. This experimental study created an increased strength cement mortar containing a high volume of FA (60 %) and bottle glass waste nanoparticles (BGWNPs). In this experiment BGWNPs were prepared and 2, 4, 6, 8 and 10 vol% of them were used as a replacement of OPC-FA binder. According to the results, by adding 0–6 % of BGWNPs to a high-volume FA matrix considerably increased the bond strength (from 12.5 % to 39.1 %). On the other hand, the findings revealed that the addition of nanoparticles (up to 6 %) caused a modest reduction in strength values. Other engineering and microstructure properties showed a similar pattern. The matrix with 6 % BGWNPs displayed the best performance when compared to other levels. The results also showed that replacing OPC by high volume FA incorporating BGWNPs significantly improved the durability of proposed mortar, such as reduction in drying shrinkage and increased acid attack and abrasion resistance. Related to the environment benefits, the proposed mortars contributed in a reduction of carbon dioxide emission, energy consumption and cost of binder by 61.9 %, 54.3 % and 50.6 % compared to OPC, respectively. To conclude, the use of BGWNPs make it possible to produce high volumes of FA-based cement mortars with acceptable mechanical and durable properties for concrete repair applications in the construction industry. Additionally, sustainability can be attained by lowering pollution, recycling waste, and finding solutions to landfill problems.

Trunk Flexor and Extensor Muscle Strength Capacity in Healthy Individuals

Objective: Generating reference values of trunk muscle strength is of value for specific age groups and gender in every society. The aim of this study was to define flexor and extensor muscle strength of the trunk and the flexion/extension ratio in healthy individuals. Materials and Methods: Hundred and two healthy individuals were included in this study. Isokinetic concentric strength of trunk flexor (Flex) and extensor (Ext) muscles of the participants were measured via an isokinetic dynamometer. Tests were performed at speeds of 60°/s and 180°/s. Maximum strength was characterized with peak torque (PT) (Flexabs, Extabs; N·m), peak torque normalized to body weight (PTNBW) (Flexnorm, Extnorm; N·m·kgbw-1), and Flexabs/Extabs ratio. Results: For angular velocity of 600/s, PT and PTNBW of flex and ext strength were higher in men; while for angular velocity of 1800/s, PTNBW of flex and ext strength were higher in women (p<0.05). Extensor strength for 600/s and 1800/s angular velocities yielded lower values than flexor strength in both genders. The Flexabs/Extabs ratios were 1.67±0.62 for 600/s and 4.93±4.60 for 1800/s. Conclusion: Trunk extensor strength was higher than flexor strength in men and women at 600/s and 1800/s angular velocities. In this study, the ratio of Flexabs/Extabs was not within the accepted range in non-active adults and there was no difference between men and women, indicating that muscle strength is not sufficient in this population. The data of this study can be used as a comparison parameter in future studies to get normative data, or common values in healthy individuals aged 18-30.

An Improved Practical Measuring Technique for Wireless Cellular Signal Path Loss Forecast in the African Terrain

Several studies on cellular signal path loss measurements at various locations under varying geographical and environmental circumstances in Africa have been conducted. Most of the techniques used, if not all, do not give consideration to the peculiar Africans’ road networks and building patterns, valleys, and hills that usually prevent the driving of motor cars within them when taking the signal strength measurements. The article presents an improved technique for wireless cellular signal strength measurement for better path loss prediction. The approach adopted for measurement is the regular grid outdoor foot technique. The technique was tested at various locations in the Ilorin metropolis and proved to be a better method of obtaining signal strength measurements. Although some of the signal strength values coincided with respect to distance when both methods were used, the drive test method overvalued the signal strength for study locations that were not in line of sight with the BTSs. These values range from 2 dBm to 8 dBm. If this technique is adopted, measurements will be taken in all vital locations that may not be accessible by means of a motor car drive test method, and more accurate values of the cellular signal strength will be obtained for better path loss prediction.

Systematic Evaluation of Isometric Maximal Muscle Strength in an Orthopaedic Cohort.

Although the lower extremities are essential for movement function and human gait, no normalized isometric maximum strength values, which include the factors gender, age, weight, height, and body mass index (BMI), have been defined to date for orthopaedic patients. To systematically analyze the isometric maximal muscle strength of a cohort in an orthopaedic outpatient clinic and to evaluate its relation to gender, age, weight, height, BMI, and the differences between diseases. Cross-sectional study. Level 4. Isometric maximal muscle strength of knee extension, knee flexion, hip abduction, and hip adduction was measured in orthopaedic patients of an outpatient clinic using a specific muscle strength measurement device. Correlation analysis was performed for age, gender, height, weight, and BMI. Patients were grouped by disease characteristics. The cohort consisted of 311 subjects (sex: 164 male, 147 female; age: 48.63 years, SD = 16.595; BMI: 26.56 kg/m², SD = 4.9). Age correlated significantly with maximal isometric muscle strength. At the age of 54 years onward, based on 133 patients, a decline in maximum isometric muscle strength was detected. Gender showed a strong influence on maximal isometric muscle strength, with significantly higher values for male patients. Furthermore, weight and height, but not BMI, correlated significantly with muscle strength. For clinical studies comparing different evidence-based training interventions for rehabilitation, it is important to consider determinants such as gender, age, weight, and height for isometric maximum strength measurement. For further validation, follow-up examinations taking into account the performance level, other target groups, and other muscle groups are required to avoid the wide dispersion of isometric maximum strength values. These results and associated determinants are highly clinically relevant and can be used as a reference for further studies in the field of musculoskeletal regeneration.

Comparative Study of the Dehydrothermal Crosslinking of Electrospun Collagen Nanofibers: The Effects of Vacuum Conditions and Subsequent Chemical Crosslinking.

Collagen nanofibrous materials have become integral to tissue engineering due to their exceptional properties and biocompatibility. Dehydrothermal crosslinking (DHT) enhances stability and maintains structural integrity without the formation of toxic residues. The study involved the crosslinking of electrospun collagen, applying DHT with access to air and under vacuum conditions. Various DHT exposure times of up to 72 h were applied to examine the time dependance of the DHT process. The DHT crosslinked collagen was subsequently chemically crosslinked using carbodiimides. The material crosslinked in this way evinced elevated Young's modulus values and ultimate tensile strength values, a lower swelling rate and lower shrinkage ratio during crosslinking, and a higher degree of resistance to degradation than the material crosslinked solely with DHT or carbodiimides. It was shown that the crosslinking mechanism using DHT occupies different binding sites than those using chemical crosslinking. Access to air for 12 h or less did not exert a significant impact on the material properties compared to DHT under vacuum conditions. However, concerning longer exposure times, it was determined that access to air results in the deterioration of the properties of the material and that reactions take place that occupy the free bonding sites, which subsequently reduces the effectiveness of chemical crosslinking using carbodiimides.

Evaluating the Effectiveness of the "Double Finish Line Technique" on Full-Crown Retention for Short Abutments: An In Vitro Study.

Achieving clinically adequate retention for cast crowns in prepared short abutments represents a major challenge for practicing dentists. Despite the important developments with adhesive cement, only a few teeth can be treated this way, and conventional preparation techniques are still employed for most crowns. Numerous options for auxiliary features exist; however, there is no consensus about one preferred method. This study aimed to evaluate the effect of a new innovative technique called the "double finish line technique" on full-crown retention for short abutments and to compare it with another modified preparation method. A comparative in vitro experimental study was conducted at the Department of Fixed Prosthodontics, Damascus University. The study sample consisted of 30 chromium-cobalt abutments and 30 metal crowns. The sample was divided into three equal groups. The first group was a control group (CG) with a 20-degree total occlusal convergence, 3 mm height, and a 0.5 mm chamfer finish line. The second group had a reduced total occlusal convergence (TOC) in the cervical 1.5 mm of the axial wall from 20 to 8 degrees. The third group implemented the so-called "double finish line technique," adding another 0.5 mm chamfer finish line 1 mm above the first finish line (DFL group). The metal crowns were cemented to metal dies with zinc-phosphate cement. Pull-off tests were applied until failure. Data were analyzed, and the differences between the three groups were detected using one-way ANOVA followed by Bonferroni's post-hoc tests (p<0.05). The mean tensile strength values for the specimens were 115.36 (SD=14.59), 149.60 (SD=11.10), and 42.46 (SD=11.54) for the TOC, DFL, and CR groups, respectively. The reduced total occlusal convergence and double finish line techniques effectively increased full crown retention and resistance cemented on short abutments.

Simple and low‐cost preparation of functionalised graphene by microwave expansion combined with ball milling grafting

AbstractThe preparation of functionalised graphene often involves consuming significant amounts of organic solvents, complicated steps, and expensive equipment. This study presented a simple, low‐cost, and efficient method for preparing well‐dispersed functionalised graphene. This method involved the microwave heating of commercial graphene precursors and ball milling of grafted expanded graphite, resulting in a short and straightforward preparation process without requiring large amounts of organic solvents. This process enabled the preparation of few‐layer graphene with a thickness of only 3.5 ± 0.5 nm. During this process, the majority of the surface oxygen‐containing groups were replaced by polyetheramine (D2000) at a grafting rate of up to 5.14%, which improved the interface adhesion strength between the graphene and the epoxy resin. The fabricated altered graphene notably enhanced the mechanical characteristics of the epoxy resin., that is, the toughening effect reached up to 171% with a graphene content of only 0.3 wt%, while the Young's modulus and tensile strength values increased by 54% and 39%, respectively. This process is cost‐effective, easy to operate, and highly efficient, making it suitable for the large‐scale production of well‐dispersed functionalised graphene.Highlights Pioneers mechanical chemical energy in graphene, a new materials science direction. First ball milling on microwave graphene, merging milling benefits with graphene. Ball milling cuts D2000 grafting time on graphene, boosting efficiency. Reduces organic solvent use, cutting costs and environmental effects. Ball milling lowers costs and impacts, aiding graphene material commercia‐lization.

Influence of the Composition of Provisional Luting Materials on the Bond Strength of Temporary Single-Tooth Crowns on Titanium Abutments.

In addition to zinc oxide-based cements, resin-based materials are also available for temporary cementation. The aim of this in vitro study was to determine the influence of the different material compositions on temporary bonds. In nine test series (n = 30), temporary bis-acrylate single-tooth crowns were bonded onto prefabricated titanium abutments with nine different temporary luting materials. After simulating an initial (24 h, distilled water, 37 °C), a short-term (7 days, distilled water, 37 °C) and a long-term provisional restoration period (12h, distilled water, 37 °C; thermocycling: 5000 cycles) in subgroups (n = 10), the bond strength was examined using a combined tensile-shear test. Statistical analysis was performed by univariate analysis of variance or a non-parametric Kruskal-Wallis test, followed by post hoc tests. Of the three resin-based materials, two showed significantly higher bond strength values compared to all other materials (p < 0.001), regardless of the storage procedure. The resin-based materials were followed by eugenol-free and eugenol-containing zinc oxide materials. Significant intragroup differences were observed between the composite-based materials after all storage periods. This was only observed for some of the zinc oxide-based materials. The results show that under in vitro conditions, not only the composition of the temporary luting materials but also the different storage conditions have a significant influence on temporary bonds.

Repair strength of 3D-printed denture base resins: Effect of surface treatment and repair material type.

The aim of the study was to investigate the effect of surface treatment and repair materials on the flexural strength of repaired 3D-printed denture base resins after thermal aging. Bar-shape specimens (64×10×3.3mm) were designed as intact (control) specimens while repair specimens were printed in sections with 2.5mm space for repair material. Printing was performed with either ASIGA or NextDent denture base material. In each material, one group received no surface treatment, while other repair groups were subjected to one of three surface treatments: (1) monomer application, (2) aluminium oxide particles-abrasion, or (3) both methods (aluminum oxide particles-abrasion and monomer application). Pairs were fixed in a customized mold then repaired with either autopolymerizing acrylic resin or flowable composite (n = 9). Repaired specimens were incubated for 48h at 37°C in distilled water and then subjected to thermal cycling (5000 cycles). A 3-point bending test was used to evaluate the flexural strength using a universal testing machine, and mode of failure determined followed by fractured surface analysis using scanning electron microscope. Data were analyzed using ANOVA and post hoc Tukey test (α = 0.05). Both resin materials showed a significant decrease in the flexural strength of repaired specimens when compared to control ones (p<0.001). Groups with no surface treatment had significantly lower flexural strength than those with surface treatment (p<0.001). Groups treated with monomer application, and with aluminum oxide particles abrasion plus monomer application had similar flexural strength values (p>0.05), which were higher than those treated with aluminum oxide particles abrasion alone (p<0.001). Specimens repaired with composite resin showed higher flexural strength than those repaired with auto-polymerized resin (p<0.05) however, specimens treated with aluminum oxide particles abrasion alone had similar values for both repair materials (p = 0.95). Adhesive failure was dominant in all repaired groups with auto-polymerized while cohesive and mixed were dominant with composite repair groups. Surface treatment improved the repair strength of 3D-printed denture base resins. Using composite resin for repair shows better strength with dominant cohesive and mixed failure suggesting that surface treatment and composite repair are suitable procedures for 3D-printed denture base repair.

High-temperature resistance of ceramic sanitaryware waste and fly ash-based geopolymer and hybrid geopolymer mortars produced at ambient curing conditions

In this study, five different hybrid geopolymer mortar mixtures were prepared, incorporating two different geopolymers and low percentages of Portland cement (PC), (16.6 % and 33.3 %). In geopolymer mixtures, 100 % ceramic sanitaryware waste (SW) and 100 % fly ash (FA) were used as precursor materials. In hybrid mixtures, the precursor materials include FA+ PC, SW+PC, and FA+SW+PC. The flexural and compressive strengths of mortars were determined up to 56 days to investigate their strength development. Additionally, the mortars were exposed to elevated temperatures up to 800 °C, separately. After the high-temperature exposure, phase (XRD) and microstructure (SEM/EDS) analyses were conducted on the selected mortars. All the hybrid geopolymers had higher flexural and compressive strengths than the geopolymers for all the curing ages. The highest 28-day flexural and compressive strength values of 5.3 MPa and 37.0 MPa were obtained on the mixture where FA+SW+PC precursors were used in equal amounts, respectively. The geopolymer and hybrid geopolymer mortars (containing 16.6 % PC) performed well under the high-temperature effect up to 800ºC. The strength values of all the mortars were obtained higher at 800ºC than at 600ºC. After high-temperature exposure, additional crystalline phases such as gehlenite were detected in hybrid mortars.

Handgrip strength as a prognostic factor for COVID-19 mortality among older adult patients admitted to the intensive care unit (ICU): a comparison Alpha (B.1.1.7) and Delta (B.1.617.2) variants

Handgrip strength (HGS) is a non-invasive and reliable biomarker of overall health, physical function, mobility, and mortality. This study aimed to investigate the possible relationship between HGS and mortality in older adult patients hospitalized with COVID-19 in the intensive care unit (ICU) by Alpha (B.1.1.7) and Delta (B.1.617.2) variants. This retrospective cohort study was conducted on 472 COVID-19 patients (222 female and 250 male) aged 60–85 years admitted to the ICU. Demographic data, underlying comorbidities, COVID-19-related symptoms, as well as laboratory and computed tomography (CT) findings were obtained from the patient’s medical records. Using a JAMAR® hydraulic dynamometer, the average grip strength value (kg) after three measurements on the dominant side was recorded for subsequent analysis. Low grip strength (LGS) was defined as an arbitrary cut-off of two standard deviations below the gender-specific peak mean value of normative HGS in Iranian healthy population, i.e. < 26 kg in males and < 14 kg in females. The findings showed lower mean grip strength and high frequency of LGS in the non-survivors patients versus survivors group and in the Delta (B.1.617.2) variant vs. Alpha (B.1.1.7) variant, respectively (both p < 0.01). The binary logistic regression analysis showed that chronic obstructive pulmonary disease (COPD) (adjusted odds ratio [OR] 5.125, 95% CI 1.425–25.330), LGS (OR 4.805, 95% CI 1.624–10.776), SaO2 (OR − 3.501, 95% CI 2.452–1.268), C-reactive protein (CRP) level (OR 2.625, 95% CI 1.256–7.356), and age (OR 1.118, 95% CI 1.045–1.092) were found to be independent predictors for mortality of patients with Alpha (B.1.1.7) variant (all p < 0.05). However, only four independent predictors including COPD (OR 6.728, 95% CI 1.683–28.635), LGS (OR 5.405, 95% CI 1.461–11.768), SaO2 (OR − 4.120, 95% CI 2.924–1.428), and CRP level (OR 1.893, 95% CI 1.127–8.692) can be predicted the mortality of patients with Delta (B.1.617.2) variant (p < 0.05). Along with the well-known and common risk factors (i.e. COPD, CRP, and SaO2), handgrip strength can be a quick and low-cost prognostic tool in predicting chances of mortality in older adults who are afflicted with COVID-19 variants.

Properties of foam concrete containing phase change material impregnated pumice

Energy consumption rises as a result of numerous electrical devices used to maintain thermal comfort of interior building areas. Using building materials with low thermal conductivity and density as well as an effective thermal energy storage plan can help to mitigate this. In order to enhance thermal performance of building, phase change material (PCM) was incorporated to foam concrete mixture in this study. Capric acid (CA)-palmitic acid (PA) eutectic mixture was prepared and impregnated with pumice (50 % by weight), a light and porous material. DSC results indicated that pumice/CA-PA composite exhibited a melting temperature of 22.84˚C and a freezing temperature of 20.85˚C, with corresponding enthalpy values for melting and freezing determined to be 85.4 J/g and 85.1 J/g, respectively. TGA analyses demonstrated that operational temperature of pumice/CA-PA composite was significantly below its thermal degradation temperature (194˚C). The prepared pumice/CA-PA composites were replaced with silica aggregate at different rates and incorporated in foam concrete mixture. Porosity and water absorption values rose as pumice/PCM content increased, yet there was a 7.2–41.1 % drop in dry unit weight when compared to reference. Compressive strength also showed a linear decrease and the lowest compressive strength value was recorded as 4.71 MPa in the presence of 40 % pumice/PCM. Thermal conductivity dropped from 0.487 W/mK to 0.167 W/mK, suggesting that foam concrete samples that were produced are all suitable as insulation materials. In peak solar radiation hours, PCM-impregnated pumice foam concrete (PFC) provided about 11.8 % and 8.72 % surface and room center temperatures compared to that of the reference in maximum case. PFC with PCM provided 6.54 % warmer surface temperature in cold weather. PFC-PCM can provide a cooler indoor temperature during peak temperature hours. Therefore, it may have a great potential to decrease the cooling load of a building.

Friction weldability of ultrafine-grained titanium grade 2

The paper presents the results of an experimental study of the friction weldability of Titanium Grade 2 with ultrafine-grained (UFG) microstructure obtained by hydrostatic extrusion and rotary swaging (HE+RS). High-speed friction welding with different rotational speed (n) values was used as a joining method. The best properties were obtained for n=7000 rpm. Metallographic observations confirmed the formation of a continuous friction joint with a changed microstructure of the base material in the thermal-mechanical affected zone (TMAZ) and a friction weld (FW). The results of the mechanical properties showed the greatest decrease in hardness in the TMAZ. The friction welded joint had an 18 % lower tensile strength value than initial state UFG Titanium Grade 2 after the HE+RS process (with UTS=1050 MPa).

Inhomogeneous deformation in the radial direction of the cold radial forged 30SiMn2MoVA steel tube

In this paper, the inhomogeneous deformation in the radial direction of the cold radial forged 30SiMn2MoVA steel tube was studied by finite element method, analyzing the microstructure and mechanical tests. The simulated result shows that the inhomogeneous deformation mainly distributed from the inner layer to the middle layer. In this region, the equivalent plastic strain rapidly decreases. The change from the middle to the outer is not significant. The distribution of microstructure and the results of mechanical properties also follow this pattern. The inner layer has the most refined grain size and the highest dislocation density. The strongest {110}<110> texture component has also been formed in the inner layer. The strength value of the inner layer is the highest, and the elongation is the lowest. There is not much difference in these indicators between the middle and outer regions. By calculating the strengthening contributions of solid solutions, dislocation density, and grain boundaries to yield strength, it was found that dislocation density is the main contributor. The calculated yield strength value is consistent with the experimental value.

Study of photosensitizer dyes for high-performance dye-sensitized solar cells application: A computational investigation

Dye-sensitized solar cells (DSSCs) offer a promising, cost-effective alternative to conventional photovoltaic systems. Organic sensitizers, capable of capturing a broad spectrum of sunlight, are key components in DSSCs, but their development and testing are often time-consuming and expensive. Quantum chemical calculations, specifically Density Functional Theory (DFT), have emerged as valuable tools to evaluate potential dye candidates, streamlining the design process and reducing costs. This study investigated the molecular structures and photophysical properties of three common dye classes used in high-performance DSSCs: natural pigments, anthocyanidin pigments, and squaraine dyes. Employing DFT and time-dependent DFT (TD-DFT) at the B3LYP/6–31G level, key parameters such as the HOMO-LUMO energy gap, free energy differences for electron injection and dye regeneration, short-circuit current density, total reorganization energy, and open-circuit voltage were analyzed. Additionally, maximum absorption wavelengths and oscillator strength values were calculated. Our findings provide valuable insights into the optical and electrical properties of these natural dyes, aiding DSSC manufacturers in selecting optimal sensitizers. This research highlights the potential of computational methods in accelerating dye development and improving the overall efficiency of DSSC technology.

Hip adduction and abduction strength values in elite-level male and female youth soccer players: A comparison between sexes, and across age-groups

ObjectivesTo report isometric hip adduction squeeze and abduction press strength values of elite-level youth male and female soccer players and examine if differences exist between sexes, and age-groups. DesignCross-sectional cohort study. SettingElite youth soccer academy. Participants102 soccer players (n = 64; male, n = 38 female) competing in the national youth soccer leagues from under (U) 14–19 years of age level (U-14, U-15, U-17, U-19). Main outcome measuresIsometric hip adduction and abduction strength values were measured with a ForceFrame in various testing positions. ResultsIsometric hip adduction and abduction strength values are presented. Male U-17 and U-19 players demonstrated significantly greater (p < 0.05) absolute(N) and relative (N/kg) hip adduction and abduction strength than their female counterparts, with large (η2 = 0.068–0.227) and medium-to-large (η2 = 0.049–0.234) effect size, respectively. Significant differences in absolute strength, but not relative strength, were observed for hip adduction and abduction between male age-groups (U-14, U-15, U-17, U-19), with hip abduction strength differences only existing between U-14 and U-17 groups. No significant differences in hip strength were observed between U-17 and U-19 groups for female players. ConclusionMale youth soccer players have higher absolute and relative hip adduction and abduction strength than females at the U-17 and U-19 level.

Spark plasma sintering of cenosphere-derived Cs/Sr-aluminosilicates for 137Cs and 90Sr immobilization in mineral-like ceramics

In this study, a promising method of spark plasma sintering (SPS) was investigated for the fabrication of ceramic matrices designed for the reliable immobilization of highly radioactive radionuclides 137Cs and 90Sr. The ceramic matrices were derived from a mixed composition of two aluminosilicate mineral-like phases – pollucite (Cs,Na)AlSi2O6 and gehlenite Sr2Al2SiO7. The originality of the developed approach lies in the utilization of hydrothermal synthesis for obtaining granulated precursor material. Hollow aluminosilicate microspheres (cenospheres) from coal fly ash served as the initial raw material, which were treated with alkaline solutions containing Cs+ and Sr2+ ions as simulants for the corresponding radionuclides. This method facilitated the achievement of high efficiency in cation removal from solutions exceeding 98 %. For a comprehensive examination of the composition and morphology of cenosphere-derived precursor particles, and the influence of sintering temperature on phase and structure formation of ceramic matrices under non-equilibrium conditions of spark plasma heating, various analytical techniques were employed. These included thermogravimetry/differential thermal analysis (TG/DTA), powdered X-ray diffraction analysis (PXRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), as well as the method of low-temperature nitrogen adsorption for determining the specific surface area. The obtained ceramic samples exhibited high values of specific density (2.688–2.915 g/cm³), compressive strength (666–808 MPa), and Vickers microhardness (1.8–2.5 GPa), attesting to their high quality and stability. The results of the hydrolytic stability assessment revealed that the leaching rates of Cs+ and Sr2+ ions from the ceramics are extremely low, within the range of 10−5–10−6 g/cm²·day. These values fully satisfy the requirements of GOST R 50926–96 and the international standard ISO 6961:1982 for solidified forms of high-level waste.