Average Strength Research Articles

Preparation of tenofovir amibufenamide fumarate spherical particles to improve tableting performance and sticking propensity by designing a spherical crystallization process

Tenofovir amibufenamide fumarate (TMF) is the first oral drug developed in Asia for the treatment of adult patients with chronic viral hepatitis B, however, further applications are limited by poor tableting performance and high sticking propensity. In this work, the spherulitic growth process of TMF has been designed and explored with the help of molecular dynamics simulation and process analysis technologies (ATR-FTIR, FBRM and EasyViewer). The spherical particles with high bulk density, good flowability and uniform particle size distribution are prepared by a simple quenching process. More importantly, experimental results show that spherical particles have higher average tensile strength (100.8% increase), higher plastic deformability and lower amount of punch sticking (87.4% decrease in 30 tablets) compared to the commercial powder products. These contributions not only shed light on the design principle of drug spherulitic growth processes, but also provide guidance for the manufacture of high-quality tablet products.

The Effect of Dimethyl Sulfoxide on the Microtensile Bond Strength of Universal Adhesives to Dentin

Objectives: The goal of this investigation was to see how a dentin pretreatment with 5% DMSO affected the microtensile bond strength (μTBS) of universal adhesives. Materials and Methods: In terms of adhesive kind and etching procedure, 32 healthy third human molars were randomly separated into eight groups. Three universal adhesives with etch-and-rinse and self-etch strategies (G-Premio Bond: GPB.ER/SE, All-Bond Universal: ABU.ER/SE, Prime & Bond Elect: PBE.ER/SE), one two-stage self-etch adhesive (Clearfil SE Bond: CSB), and one two-stage etch-and-rinse adhesive (Adper Single Bond 2: ASB) were employed in with and without DMSO modes (group/N=16). Dentin pretreatment was conducted with 50 μl of 5% DMSO, followed by the use of an adhesive. The μTBS of samples was tested. The influence of adhesive type and DMSO application on bond strength was evaluated using a two-way analysis of variance (ANOVA) (=0.05). Results: The dentin-adhesive μTBS was significantly affected by DMSO administration (P=0.003), type of adhesive (P=0.001), and the combination of DMSO application and type of adhesive (P=0.027). In the DMSO application mode, the average bond strength of universal adhesives with etch and rinse mode was significantly higher than in the non-application mode, but in the self-etch technique, there was no significant difference pattern between DMSO applications and non-application modes in terms of adhesive bond strength. Conclusion: The use of DMSO in an etch-and-rinse technique can dramatically enhance the universal adhesive-dentin μTBS and has promise benefits for clinicians in terms of enhancing dentin bond performance.

A measurement of the escaping ionising efficiency of galaxies at redshift 5

The escaping ionising efficiency from galaxies, $f_ esc ion $, is a crucial ingredient for understanding their contribution to hydrogen reionisation, but both of its components, $f_ esc $ and $ ion $, are extremely difficult to measure. We measured the average escaping ionising efficiency $ esc ion of galaxies at $z=5$ implied by the mean level of ionisation in the intergalactic medium via the Lyman-alpha forest. We used the fact that $ N ion UV f_ esc ion $, the product of the ionising output and the UV density $ UV $, can be calculated from the known average strength of the UV background and the mean free path of ionising photons. These quantities, as well as $ UV $, are robustly measured at $z We calculated the missing factor of $ esc ion at $z=5$ during a convenient epoch after hydrogen reionisation had been completed and the intergalactic medium had reached ionisation equilibrium but before bright quasars began to dominate the ionising photon production. Intuitively, our constraint corresponds to the required escaping ionising production from galaxies in order to avoid over- or under-ionising the Lyman-alpha forest. We obtained a measurement of $ esc ion /$erg $ at $z=5$ when integrating the $ UV $ down to a limiting magnitude $M_ lim =-11$. Our measurement of the escaping ionising efficiency of galaxies is in rough agreement with both observations of early galaxies and with most models.

Additive manufacturing of interlocking glass masonry units

AbstractIn comparison to traditional glass casting, glass additive manufacturing (AM) presents an opportunity to increase design flexibility and reduce tooling costs for the production of highly variable geometries. While the latter has been extensively explored for masonry units, there is minimal research on the former for its viability to produce structural building components. This paper encompasses design, manufacturing, and experimental testing to assess the feasibility of using glass AM to produce interlocking masonry units for the construction industry. The glass 3D printer employed in this study is capable of printing a maximum volume of 32.5 $$\times $$ × 32.5 $$\times $$ × 38 cm–suitable for producing full-size masonry units. As part of this work, we discuss how to adapt design guidelines for glass AM to produce interlocking units. To evaluate fabrication ease and structural performance, three fabrication methods, Fully Hollow, Print-Cast, and Fully Printed, are compared. To compare the accuracy, repeatability, and structural capacity of each masonry unit, geometric analysis, surface roughness, and mechanical testing is conducted. Results varied by fabrication method, with average strength ranging from 3.64$$-$$ - 42.3 MPa for initial fracture and 64.0–118 MPa for ultimate strength. Accuracy in print dimensions was less than 1 mm with a standard deviation of 0.14–1.6 mm. Results demonstrated that Fully Hollow masonry units provide a more immediate path to implementation, while Fully Printed units have the potential to provide an entirely glass, transparent, and circular building component fabrication method.

Handgrip Evaluation Before and After Pulmonary Rehabilitation Therapy in Patients With Chronic Obstructive Pulmonary Disease (COPD).

Introduction Chronic Obstructive Pulmonary Disease (COPD) is a systemic disease characterized by skeletal muscle dysfunction, leading to increased morbidity and mortality and deteriorating quality of life. Pulmonary rehabilitation therapy improves symptoms and long-term adherence. This study aimed to evaluate how COPD patients respond to pulmonary rehabilitation therapy and its correlation with handgrip strength measurements. Materials and methods A prospective cohort study was conducted in patients over 45 years old with a spirometric diagnosis of COPD from a specialized reference center in Bucaramanga. Handgrip strength was measured before and after completing the pulmonary rehabilitation program. Patients with neurological or cognitive impairments, decompensated cardiovascular disease, nutritional diseases, or those in a telerehabilitation program were excluded. Results Seventy-one patients were included in the study, with 66.2% completing follow-up after the program. The average age was 73.38 years (SD ±7.77), 53.52% were women, and 60.56% had a history of smoking. After the follow-up, the average handgrip strength delta was 1.64 kg (SD ±3.48) p<0.001, 74.47% of them representing a positive result after pulmonary rehabilitation program. A higher Charlson index correlated with a positive delta, while a negative delta correlated with a lower Charlson index (p=0.01). A positive handgrip strength delta was associated with higher baseline quality of life scores. Conclusions Periodic handgrip strength measurements predict frailty and muscle dysfunction in COPD patients. Pulmonary rehabilitation therapy isa simple and cost-effective intervention that correlates with the improvement of indirect prognosis and survival indicators.

An efficient synergistic double-sided friction stir spot welding method: A case study on process optimization, interfacial characteristics and mechanical properties of 2198-T8 aluminum‑lithium alloy joints

Friction stir spot welding has important applications in the joining of thin metallic plates. However, the asymmetric thermomechanical action inherent in the single-sided friction stir spot welding inevitably generates the hook defect at the joint interface, and the defect deteriorates with the improvement of the interfacial metallurgical bonding, which causes the irreconcilable contradiction and significantly restricts the breakthrough of the process stability and welding efficiency. The synergistic double-sided probeless friction stir spot welding (SDP-FSSW) technology proposed in this study adopts a dual-axis synergistic control system, which introduces intense plastic deformation from both sides of the interface to form a wavy hook by accurate axial motion during the welding process. This innovative process solves the problem of hook warpage while realizing rapid metallurgical bonding and mechanical interlocking at the interface, thus obtaining AA2198-T8 aluminum‑lithium alloy spot joints with a tensile/shear strength exceeding 9kN in a short dwell time (0–3 s). Through response surface methodology, the optimal process parameters are identified, i.e. rotation speed of 603 rpm, dwell time of 3 s, and plunge depth of 0.26 mm, at which condition the average joint strength is 13.0 ± 0.5kN, a 47 % increase compared to an optimized joint of single-sided probeless friction stir spot welding (8.9kN). The optical microscope examination shows that the wavy hook can be adjusted by the rotation speed and the higher rotation speeds will make the wave disappear and produce an approximately straight interface. The fractographic analysis shows that the wavy hook can inhibit crack propagation and has good mechanical interlocking effect, but the flat hook at high rotation speeds leads to crack propagation directly along the interface, and the failure mode is changed from plug-pull fracture to interfacial fracture. Therefore, the joint strength at 1000 rpm is only 7.0kN, which decreases by about 47 % compared with the optimal strength. The electron backscattering diffraction analysis shows that continuous dynamic recrystallization occurs in the hook region and good metallurgical bonding is formed, and there are also some discontinuous dynamic recrystallized grains distributed between the large grains due to the larger strain rates and lower temperature at the interface during the SDP-FSSW process. It has been found that the wavy hook with good metallurgical bonding and mechanical interlocking can be introduced in spot welded joints by controlling the interface forming, which is a viable method to create high quality, efficient and reliable spot joints.

3D printing of high-stiffness and high-strength glass fiber reinforced PEEK composites by selective laser sintering

Glass fiber reinforced poly-ether-ether-ketone (PEEK) composites are emerging as structural materials of multifunctional devices in space applications, due to their outstanding mechanical properties, electrical insulating properties, and resistance to irradiation. Here, a new approach for preparing glass fiber/PEEK powders tailored for selective laser sintering (SLS) process is proposed. The surface of glass fiber is modified with the sulfonated PEEK following the designed procedure. The flowability of glass fiber/PEEK powders is also improved by adding the nano-scale SiO2 flow agent. The glass fiber reinforced PEEK composites are successfully 3D printed using the glass fiber/PEEK powders. Further, the enhancement of interfacial bonding between PEEK and glass fiber is analyzed through quasi-static tension tests and scanning electron microscopy (SEM) for the SLSed glass fiber reinforced PEEK composites. The average ultimate tensile strength reaches approximately 100 MPa using these optimal process parameters, while the average elastic modulus is around 7 GPa. Finally, the upper limit of fiber weight fraction is evaluated with the X-ray computed tomography (XCT) and the high-fidelity discrete element method (DEM) simulation.

PM1.0 removal enhancement in cooperated electric-ionic field by negative air ions carbon fiber electrode

The study focuses on improving the removal efficiency of submicron particles using negative air ions (NAIs), which are challenging to remove. To enhance this efficiency, cascaded carbon fiber tubular (CFT) chargers were designed to boost particle charging. Through experiments and numerical simulations, the chargers’ enhancement mechanisms, cooperation effects, and overall performance were evaluated. The optimal configuration for the CFT charger was identified as a gap distance (d = 2.0 r0) and grounded electrode length (L0 = 4πr03) that ensures high collection efficiency (96.7 % for 0.5 μm particles at 4 m/s) and ultra-low ozone generation (7.25 ppb). The study found that while the average electric field strength (E¯) and ion density significantly influence charging, an unusual improvement in collection efficiency was observed the charger with d = 2.0 r0 at u = 3 m/s, likely due to the potential predominance of the maximum electric field strength (Emax) at relative higher velocity. Besides, the CFT charger demonstrated balanced performance compared to other reported works, although higher relative humidity (80 ± 5 % RH) inhibits removal efficiency, which can be mitigated by reducing gas velocity.

Machine learning methods to discover hidden patterns in well-being and resilience for healthy aging.

A whole person approach to healthy aging can provide insight into social factors that may be critical. Digital technologies, such as mobile health (mHealth) applications, hold promise to provide novel insights for healthy aging and the ability to collect data between clinical care visits. Machine learning/artificial intelligence methods have the potential to uncover insights into healthy aging. Nurses and nurse informaticians have a unique lens to shape the future use of this technology. The purpose of this research was to apply machine learning methods to MyStrengths+MyHealth de-identified data (N = 988) for adults 45 years of age and older. An exploratory data analysis process guided this work. Overall (n = 988), the average Strength was 66.1% (SD = 5.1), average Challenges 66.5% (SD = 7.5), and average Needs 60.06% (SD = 3.1). There was a significant difference between Strengths and Needs (p < 0.001), between Challenges and Needs (p < 0.001), and no significant differences between average Strengths and Challenges. Four concept groups were identified from the data (Thinking, Moving, Emotions, and Sleeping). The Thinking group had the most statistically significant challenges (11) associated with having at least one Thinking Challenge and the highest average Strengths (66.5%) and Needs (83.6%) compared to the other groups. This retrospective analysis applied machine learning methods to de-identified whole person health resilience data from the MSMH application. Adults 45 and older had many Strengths despite numerous Challenges and Needs. The Thinking group had the highest Strengths, Challenges, and Needs, which aligns with the literature and highlights the co-occurring health challenges experienced by this group. Machine learning methods applied to consumer health data identify unique insights applicable to specific conditions (e.g., cognitive) and healthy aging. The next steps involve testing personalized interventions with nurses leading artificial intelligence integration into clinical care.

Microstructural and mechanical properties analysis of SS 316L structure fabricated using CMT-wire arc additive manufacturing

Integrating robotic arm technology with cold metal transfer (CMT) has revolutionized wire arc additive manufacturing (WAAM). The research work consists of the fabrication of SS 316L WAAM using the CMT technique. Investigations of mechanical and microstructural properties, i.e. residual stress measurement (RSM), microhardness (MH), ultimate tensile strength (UTS), percentage elongation (PE), and microstructure of WAAM sample and cold rolled (CR) plate, results were compared. WAAM attained an UTS of 590 MPa, with an average yield strength (YS) of around 302 MPa, exceeding the CR plate’s UTS of 557 MPa while maintaining a similar YS of 305 MPa. WAAM and the CR plate exhibited nearly identical PE, with 64% and 62% values, respectively. Residual stress analysis revealed that the WAAM sample showed an average compressive residual stress of 124 MPa, accounting for 87% of the average residual stress observed in the CR plate, which measured 142 MPa. The MH profile of WAAM revealed an average value of 230 HV0.5, accounting for 88% of the MH observed in the CR plate at 260 HV0.5. The performance of WAAM closely matched that of the CR plate in terms of residual stress and MH.

Development of Ti3SiC2 MAX phase tubular structures for solar receiver applications

Solar receiver tubes are key components of concentrating solar-thermal power (CSP) systems that harvest solar energy. For better efficiency, the Gen3 CSP receivers, which collect heat into a heat transfer fluid, require a temperature exceeding 700 °C during operation and need to perform under extreme conditions of high temperature and high thermal stress. Operators are seeking CSP designs using new high-temperature structural materials with high thermal conductivity and high creep resistance to achieve a design life of 30 years and thus help recover the plant capital cost sooner. MAX phase materials, which consist of an early transition metal element, an A-group element, and carbon or nitrogen, are expected to exhibit high creep resistance as well as high fracture toughness. In this paper, we describe fabricating both (1) dense Ti3SiC2 MAX phase disks and (2) short-length tubes using field-assisted sintering technology (FAST). First, the disk samples that we fabricated are fully dense and contain ≈90 % Ti3SiC2 MAX phase materials and ≈10 % TiC phase materials. We determined a flexure strength of 519 ± 32 MPa by conducting a four-point bending test at room temperature with rectangular bar samples of ≈100 % density. The thermal conductivity of the Ti3SiC2 MAX phase samples, measured by light-flashing analysis, decreases linearly from a value of 41 W·m−1·K−1 at room temperature to a value of 36 W·m−1·K−1 at 650 °C. A solar reflectance measurement of the Ti3SiC2 MAX phase revealed that, temperature increases from 400 to 1400 °C, thermal emittance increases from 0.39 to 0.49, while selectivity decreases from 1.8 to 1.4, respectively. Whereas the surface oxidized MAX phase samples after 100 h exposure to air at 1000 °C exhibit that of SiC.Next, we discuss fabrication of the crack-free Ti3SiC2 MAX phase tubular structures accomplished by using FAST processing in graphite bedding. A Ti3SiC2 MAX phase content of > 95 % with traceable ≈3% remaining TiC phase and ≈15 % porosity were demonstrated after high-temperature annealing. An average fracture strength of ≈250 MPa was determined with Ti3SiC2 MAX phase tubes of ≈85 % density by diametral compression testing at room temperature. Our work demonstrated that using FAST processing to produce Ti3SiC2 MAX phase tubular structures for CSP receiver applications is a viable approach.

SIFAT MEKANIS KOMPOSIT MATRIKS ALUMINIUM BERPENGUAT ABU JERAMI DENGAN METODE METALURGI SERBUK

The powder metallurgy method is one method for making metal matrix composite products. This method provides researchers with material engineering.This study aims to determine how the effect of variations in mixing time and sintering holding time affects the hardness and compressive strength of composites made of aluminum powder and straw ash. The composition of this composite is 90%wt Aluminum and 10%wt straw ash. Preparation of specimens using powder metallurgy method. Mixing time variations were applied for 120, 150 and 180 minutes with the dry mixing method. Variation of sintering holding time was applied for 60, 120 and 180 minutes at 550°C.The mechanical test carried out are hardness test and compression test. The results showed that the optimum hardness value was found in the specimens with a mixing time of 150 minutes and sintering holding time of 180 minutes with an average hardness of 96 HRF. The optimum compressive strength is found in specimens with a mixing time of 150 minutes and sintering holding time of 120 minutes with an average compressive strength of 101.28 MPa. It can be concluded that mixing time and sintering holding time affect the hardness and compressive strength of the metal matrix composite.

Coupling effect of dynamic power and oscillation path on butt weld formation and melt flow behavior during aluminum alloys

The influence of the coupling effect between dynamic power and oscillation path on the formation of weld seams and the fluid behavior of the molten pool during laser welding of 5A06 aluminum alloy was investigated through numerical simulation and experimentation. Three power modes were compared in the experiments: equal power (EP), delayed dynamic power (D-DP), and non-delayed dynamic power (ND-DP). The experimental results show that both D-DP and ND-DP modes are favorable to improve the mechanical properties. Among them, the joints formed under the D-DP mode exhibit the best mechanical properties, with an average tensile strength reaching ≈ 99.1% of the base material, which is an increase of ≈ 35.3% and ≈ 5.6% compared to the EP and ND-DP modes, respectively. Numerical simulation results indicate that the D-DP mode effectively mitigates the average flow velocity of the molten pool, reduces the collision effects between liquid flows, suppresses the impact of fluid on the keyhole walls, and improves the stability of the keyhole and the welding process, thereby enhancing the mechanical properties of the joints.

ISHELL K-band Survey of Class I and Flat Spectrum Sources: Magnetic Field Measurements in the Protostellar Phase

We perform the first magnetic field strength survey of Class I and Flat Spectrum (FS) sources using K-band observations with iSHELL. We obtained new observations of 42 Class I and FS sources and additionally included 10 sources from the archive. We detect photospheric lines in 44 of the sources, in addition to Brγ, H2, and CO emission in several objects. We model the photospheric absorption lines of 32 Class I and FS sources and measure their magnetic field strengths, K-band temperatures, gravities, projected rotational velocities, and infrared veiling values. We put the physical properties of Class I and FS sources in context by comparing them to the values derived for a sample of Class II sources. We find that (a) the average magnetic field strength of Class I and FS sources 〈B〉 = 2.0 ± 0.15 kG is consistent with the average magnetic field strength of Class II sources 〈B〉 = 1.8 ± 0.15 kG, and (b) the average gravity of Class I and FS objects logg=3.43±0.07 is lower than the average gravity of Class II sources logg=3.75±0.04 , although there is significant overlap between both gravity distributions. Furthermore, using stellar evolutionary models, we deduce that Class I and FS sources have a median age of ∼0.6 Myr, and are, as a group, younger than the Class II stars with a median age of ∼3 Myr. Our results confirm that Class I and FS sources host strong magnetic fields on their photospheres. Thus, it is likely that these sources accrete disk material through a magnetosphere similar to the more evolved T Tauri stars.

Bond behavior of reinforcing steel bars in metakaolin – calcium carbide residue-based geopolymer concrete

The bond property of concrete is a key characteristic of concrete that affect the structural activity of reinforced concrete beams. Concrete produced from geopolymer has the prospect to replace concrete produced from ordinary Portland cement (OPC) for structural applications. Therefore, this research evaluates the bond behavior of metakaolin-calcium carbide residue (CCR)-based geopolymer concrete for use in in situ structural applications. Comparative studies were carried out on concrete made of geopolymer and OPC. The embedment lengths (5ϕ and 7ϕ) and reinforcing bar diameters (14 and 16 mm) were varied and the bonding activity of the different concrete types was studied. Additionally, the qualities of the concrete produced were assessed, including density, ultrasonic pulse velocity, and compressive and flexural strengths. Generally, the metakaolin-CCR-based geopolymer concrete samples had the best mechanical properties, followed by metakaolin-based geopolymer and OPC concrete, respectively. Bond activity enhanced when embedment length and diameter of reinforcement were reduced in all types of concrete. Thus, with a reinforcing bar diameter of 14 mm and an embedment length of 5ϕ, the average bond strength of the metakaolin-CCR-based geopolymer concrete was 14.3MPa, which was 18.87% and 105.46% higher than that of the metakaolin-based geopolymer and OPC concrete, respectively. Influenced by experimental conclusions, it can be established that the metakaolin-CCR-based geopolymer concrete has the capacity to be used in place of OPC concrete in bond applications where steel reinforcing bars are employed.

Comparison between Compression Strength of Composite Resin with and without Stamp Technique

Background: This study aims to determine whether there is a difference in compression strength between resin composites that use the stamp technique and those that do not use the stamp technique. Objective: To identify the effect of the stamp technique with occlusal matrix on the compression strength and compare it with the one without stamp technique. Materials and methods: This study used an occlusal matrix from a transparent impression made of silicone to print the occlusal teeth. This transparent impression was attached to the resin surface composite prior to polymerization and remained on the surface until polymerization ended. The advantage of using this transparent occlusal matrix is ​​that the light cure can penetrate through the transparent layer of the impression. It can be used to isolate oxygen during polymerization. Results: The average compression strength of composite resin with the stamp technique was 128.5300 ±17.23023 MPa, while composite resin without the stamp technique was 91.2460 ±8,72802 MPa. Conclusion: This study showed the difference between the two test groups, where the resin composite using the stamp strength had a higher compression strength.

Local and global mechanical properties of orbital friction stir welding on API X65 PSL2 steel / Inconel 625 clad pipes

Orbital friction stir welding (FSW) is a promising approach to joining clad pipes. In this work, the influence of individual process parameters on the material flow even as, mechanical properties in orbital friction stir welded clad pipes is investigated. Due to the local heterogeneous microstructures within the weld, joints were evaluated by optical and scanning electron microscopy (SEM), microhardness, and digital image correlation (DIC). A microhardness increase was observed, with a maximum of 380 HV0.5 within the Inconel 625 and 265 HV0.5 within the X65 steel stir zones. Sound joints had an average ultimate tensile strength (UTS) exceeding up to 13% of the calculated theoretical tensile strength, which is obtained considering the minimum tensile strength of both materials. Additionally, failure occurred in the base material during the tensile testing, where the local strain in the stir zones of the X65 steel and Inconel 625 were only 3.3% and 10%, respectively. In summary, this investigation shows friction stir welded joints of API X65 steel and Inconel 625 clad pipes with high mechanical properties.

ДИНАМИЧЕСКИЙ АНАЛИЗ КЛИНИКО-МЕТАБОЛИЧЕСКИХ ПОКАЗАТЕЛЕЙ У ПОДРОСТКОВ С ОЖИРЕНИЕМ В ГЕНДЕРНОМ АСПЕКТЕ

Obesity in children and adolescents makes a significant contribution to the comorbidity of the pathology of the adult population, which is primarily associated with the development of metabolic syndrome. Of particular interest are gender differences in the detection and progression of symptoms of metabolic disorders. The purpose of the study was to conduct a dynamic analysis of clinical and metabolic indicators in adolescents with obesity in the gender aspect. The study reflects the dynamics of anthropometric indicators (body mass index and waist circumference to hip circumference ratio), metabolic indicators of carbohydrate and lipid profiles in the gender aspect. At the same time, no statistically significant gender differences were found both during the initial examination and after 12 months, however, there was a violation of glucose tolerance in girls in dynamics, which is probably associated with the progression of obesity. Correlations showing significant differences between the anthropome are interesting. Thus, among young men, the average strength of the relationship between age and glucose levels after exercise (correlation coefficient -0,59) and blood insulin content (correlation coefficient 0,55) turned out to be significant. At the same time, higher BMI values were accompanied by an increase in fasting blood glucose (correlation coefficient 0,6). Similar direct relationships between BMI and indicators of carbohydrate and lipid metabolism were observed in girls: the higher the BMI, the higher the levels of glucose after exercise, insulin and triglycerides in the blood (correlation coefficients 0,63, 0,81 and 0,52).

Technology of Manufacturing Hollow Soil-Cement Blocks

The author analyzed technological solutions for the production of blocks from soil cement. It is proposed to make soil cement blocks from portland cement brand 400 in the amount of 20 % of the mass of soil and water. Experimental addition of fly ash to the solution in different amounts depending on the cement content. It is proposed to add ash removed from the Darnytsya thermal power plant, which was sifted through a 4 mm sieve, because the ash contains a significant amount of impurities. The content of inclusions from 1 to 4 mm was up to 40 %. It is proposed to make blocks from soil cement with the addition of fly ash with the aim of improving the thermotechnical properties. It is proposed to make soil-cement blocks with two voids. To ensure high-quality compaction of products in forms, the moisture content of the content for most soils should be within 14–23 %. The maximum force that the sample can withstand was taken as a destructive load. It was decided that the use of fly ash as part of the mixture in the production of soil cement gives a positive effect. With an increase in the period of exposure of samples in water to 90 days, the average compressive strength of soil cement samples without additives and with the addition of the appropriate percentage of fly ash increases.

Experimental In-Plane Shear Performance of Masonry Infill Walls Assembled with Cementitious Matrix–Grid Composites

This paper presents a study on strengthening infill walls using composite materials to enhance shear capacity. The cementitious matrix-grid (CMG) material was employed for this purpose. Various configurations of the CMG, including single or double layers, applied to one or both sides of the wall, with or without anchorage, were tested. The study consisted of two stages. Initially, the mechanical properties of the bricks, mortar, and CMG mortar were determined using twenty-seven specimens. In the second stage, ten specimens, divided into five groups with one group left unstrengthened, underwent shear tests. Shear strength and shear strain relationships were determined for each specimen. Comparative analysis between strengthened and unstrengthened specimens revealed the effectiveness of the strengthening technique. The strengthened specimens exhibited superior structural performance compared to the control specimens. Specifically, the average maximum shear strength of all strengthened specimens surpassed that of the controls. Moreover, double-layer strengthening notably improved ductility. The findings suggest that applying a double layer of CMG to both sides of the wall with anchorage is the most effective method for strengthening. CMG composites significantly enhance the shear strength of infill walls and promote ductile failure. The comparisons of different strengthening combinations can contribute significantly to the existing literature and the construction sector by offering retrofitting options that can be tailored to address various economic and temporal, as well as target strengthening considerations.