Strong Bonds Research Articles

ANALYSIS THE INFLUENCE OF VARIATION SHEAR REINFORCEMENT SPACING IN REINFORCED CONCRETE BEAM TESTING

Beams are crucial components of a building structure that require attention during the design phase. Several failures in beams occur due to inadequate installation of reinforcement according to the planned procedures or designs, which can lead to structural failures. Based on the analysis and testing of three reinforced concrete beams B1, B2, and B3 conducted in the laboratory, the maximum axial compressive strength obtained is 125 kN and the flexural tensile strength is 5.56 MPa. The deflection values observed for beam B1 7.05 mm, beam B2 8.4 mm, and beam B3 18.75 mm. The crack widths observed for beam B1 range from 0.1 to 0.4 cm, beam B2 range from 0.1 to 5 cm, and beam B3 range from 0.1 to 12 cm. Deflection values and crack patterns/failure modes observed in reinforced concrete beams B1, B2, and B3, it is evident that the most significant failure patterns occur in Beam B3 with a stirrup spacing @200mm compared to stirrup spacings @100mm and @150 mm. The use of 45° hooks on stirrups results in diagonal failure in beams. This is attributed to the strong bond between the concrete and the installed reinforcement, thereby interlocking with each other.

Computational investigation of amide derivative as potential anti-carbapenem-resistant Pseudomonas aeruginosa

Recent findings indicate a surge in morbidity and mortality probabilities associated with infections caused by carbapenem-resistant strains, underscoring an urgent need for the development of effective drugs against these strains. This study employs Density Functional Theory (DFT) with the ωB97XD/6–311++G (2d, 2p) model to investigate the electronic, structural, and the biological potential of N1, N10-Bis (1,3,4-thiadiazolo (3,2-a)pyridine-2-yl)-decanediamide (TDZ). Fourier Transform Infrared Spectroscopy highlights significant assignments related to C-H, C=C, and N=H functionalities, aligning well with experimental results. Chemical reactivity analysis orders the energy gap as TDZ_Acetone > TDZ_Gas > TDZ_DMSO > TDZ_Water. The visualization of weak interaction in wider regions of steric repulsions are seen for TDZ in solvents DMSO, acetone and water as well as transformation of strong halogen bonds to van der Waals interaction. Visual findings reveal the propensity of the compound to form hydrogen bonds with protein targets due to high electron localization around hydrogen atoms. Pharmacokinetics studies indicate TDZ's favorable intestinal absorption at 50.525 %. Moreover, TDZ does not inhibit hERG 1, eliminating the risk of potassium channel blocking-induced cardiac arrhythmia. Molecular docking analysis shows TDZ's enhanced biological activity and stronger binding affinity with 5XNW, with a binding affinity of −4.5 kcal/mol and the formation of five conventional hydrogen bonds. Comparatively, for 4AKX, the standard drug Dori records eight hydrogen bond interactions at −6.8 kcal/mol, while TDZ records nine interactions at −8.6 kcal/mol. This suggests that, despite Dori's favorable interactions and good biological activity, TDZ exhibits superior binding affinity and heightened biological activity potential, positioning it as a promising drug candidate against carbapenem-resistant Pseudomonas aeruginosa infections.

The Association Between Epidural Analgesia During Labor and Mother-Infant Bonding

(J Clin Anesth. 2022;80:110795 | https://doi.org/10.1016/j.jclinane.2022.110795 |) Labor involves significant pain for the mother, influenced by various factors. The ability to control this pain positively impacts the mother’s psychological and physiological well-being. Epidural analgesia is commonly chosen for pain relief during vaginal delivery. Mother-infant bonding, crucial for a child’s later attachment and self-perception, develops from pregnancy into early childhood. A strong bond correlates with positive parenting, cognitive development, and improved neurobehavioral outcomes. Impaired bonding, affecting 7% to 11.3% of mothers, can lead to long-term issues for both mother and child, including depression, anxiety, and socioemotional challenges. Several risk factors for impaired bonding include primiparity, negative feelings toward pregnancy, low birth weight, higher education, and postpartum depression. Pain during labor, a significant element, may impact the bonding process. Studies on epidural analgesia’s association with postpartum depression yield conflicting results, and no research examines its connection to mother-infant bonding. The primary study’s aim is to explore the link between epidural analgesia and mother-infant bonding, with a secondary focus on its association with postpartum depression immediately after childbirth.

Crystallinity regulation of ZIF-67 via defective MgO layer made by high voltage-assisted oxidation approach for optimal 4-nitrophenol reduction

Due to their unique structural characteristics, metal-organic frameworks (MOFs) have emerged as favorable contenders for photocatalytic applications. In this study, the crystallization of ZIF-67, a subclass of MOFs, on Mg and MgO substrates via dip coating was explored, and the resulting materials were employed as a photocatalyst for the 4-nitrophenol reduction. Due to the defective surface resulting from plasma activity during the high-voltage-assisted oxidation of AZ31 Mg alloy, MgO significantly impacts the crystallization of ZIF-67. This influence promotes the formation of a stable foundation and strong bonds, contributing to the emergence of a regular and symmetrical structure. This differs from the asymmetrical and irregular structure observed in ZIF-67@Mg when ZIF-67 is grown directly on the Mg substrate. Hence, the ZIF-67@MgO catalyst demonstrated remarkable enhancements in the reduction of 4-nitrophenol to 4-aminophenol, achieving an efficiency of approximately 97.12 % within 12 min under visible light. Importantly, the catalyst exhibited no stability decay even after ten consecutive cycles, surpassing the performance of previously reported catalysts. This research sheds light on the superior capabilities of ZIF-67@MgO in the context of visible-light-driven reduction of 4-NP. The results suggest potential for future progress in creating effective and eco-friendly photocatalytic materials for addressing environmental challenges.

Performance and Life Cycle Assessment of Composites Reinforced with Natural Fibers and End-of-Life Textiles

The growing need for materials that are eco-friendly and sustainable in the industrial sector has shifted focus from synthetic fossil to natural fibers, alongside the utilization of recycled polymer textiles. This research introduces a novel method for using end-of-life textiles, such as polyester and polyamide fabrics, in the production of composite materials, aiming to lessen textile waste and enhance material longevity. The mechanical attributes of flax fabric (FF), flax–recycled polyamide fabric (F/RPA), and flax–recycled polyester fabric (F/RPES) composite laminates are assessed through tensile, flexural, interlaminar shear, and Charpy impact tests. The study revealed that the addition of end-of-life synthetic fibers improves tensile strength, while the trend in modulus values suggests that flax provides a high degree of stiffness to the composites, which is moderated by the addition of synthetic fibers. This effect is consistent across both tensile and flexural testing, although the impact on stiffness is more significant in bending. The inclusion of polyester fibers in the composite laminate resulted in significant enhancements, with an 11.1% increase in interlaminar shear maximum force, a 17.4% improvement in interlaminar shear strength, and a 67.1% rise in un-notch impact energy, compared to composites made with only flax fiber (FF). The microscopic examination uncovered the internal structure and demonstrated a clear, strong bond between the polyester and polyamide fiber layers with the flax fibers. Additionally, the life cycle assessment revealed that the F/RPES composite had less environmental impact than FF and F/RPA in all 18 categories analyzed. This indicates that the environmental footprint of producing F/RPES is smaller than that of both FF and F/RPA.

Electronic and magnetic properties of Mn-doped and Mn-X (F, Cl, Br, I) co-doped modulated monolayer SnSe2

The density functional theory is employed for learning the modulation of the electronic structure and magnetic properties of monolayer SnSe2 by an Mn atom and by co-doping an Mn atom with a halogen atom. It is found that intrinsic SnSe2 is nonmagnetic, which is consistent with the properties of semiconductors. Following Mn atom doping, the doped system is magnetic and the magnetic moments are primarily responsible for the Mn atom. After co-doping the Mn atom with halogen atoms, the doped system's total magnetic moments are decreased. The examination of the electronic structure demonstrates that the doping of the Mn atom and the co-doping of the Mn atom with halogen atoms lead to the introduction of impurity energy levels into the doped system, which appear only in the spin-up part and do not cross the Fermi energy level. There is asymmetry between the spin-up and spin-down energy bands and the doped system exhibits magnetic semiconductor properties. The hybridization of the p-orbitals of the halogen atoms and the 3d orbitals of the Mn atom is primarily responsible for the introduction of impurity energy levels in the energy bands of the doped system. In the Mn-doped system, ionic bonds were shaped between Mn and Se. In the co-doped system, strong ionic bonds were shaped between the Mn atom and F, Cl atoms, and covalent bonds were shaped between the Mn atom and Br, I atoms.

Effect of Calcium Carbonate as Filler on the Physicomechanical Properties of Polypropylene Random

To minimize the cost of production and enhancement pipe quality, this research aims to gain insights into the physical and mechanical characteristics of high-performance polypropylene random filled with rigid inorganic calcium carbonate particles at various content levels, with a specific focus on how the toughness of PPR changes. Virgin Polypropylene Random PPR, a new material extracted from a homopolymer polypropylene, is used as a matrix with 10, 20, 30, 40, and 50 wt. % of CaCO3. The density, melt flow rate, tensile strength, tensile strain, modulus of elasticity, and hardness are used to evaluate the quality of the material. The results showed that the density, the modulus of elasticity, and the hardness increased with increasing the percentage of CaCO3. As the percentage of CaCO3 increased, the melt flow rate decreased. The tensile strength and strain increased to 28.7 MPa and 533.25%, respectively at 20 wt.% of CaCO3, with 14.8% and 6.65% reaching gains compared to the virgin PPR (25 MPa and 500%). The enhancement of the mechanical properties is thanks to the presence of stiffer and rigid particles of CaCO3 that act as a reinforcing agent. Moreover, when CaCO3 is well dispersed, it forms a strong bond with the polypropylene matrix, and facilitates the transfer of stress from the matrix to the fillers, resulting in increased stiffness. The optimum percentage of CaCO3 to add into the inner layer of extruded PPR pipes is at a composition of the filler of 20 wt. %.

Research on bonding mechanism of Cu/Al corrugated composite plates rolled by flat finish roll bonding

Cu/Al composite plates with excellent properties were prepared using a new type of corrugated cold roll bonding (CCRB) + flat finish roll bonding (FFRB) process. In this paper, the bonding mechanism and interface strengthening mechanism of FFRB process were studied by experimental and numerical simulation methods. Furthermore, the mechanical properties of typical positions were studied. The results indicate that the FFRB process reduces the difference in bonding properties between the peak II and trough II. The bonding strength increases with the increase of reduction. When the reduction reaches 60%, the peel strength of interface at peak II and trough II is 45.04 N/mm and 35.83 N/mm, respectively. Meanwhile, the strong bond at the interface is conducive to transferring the center of strain localization (SL) to the Al side with excellent plasticity, delaying the necking and fracture of Cu/Al composite plates. After FFRB, Cu/Al composite plates develop from the annealed metallurgical bonding interface to the staggered distribution of metallurgical bonding and new bonding interface. The newly formed bonding interface and the particle pinning effect of the intermediate metal compounds (IMC) fragments work together to strengthen the bonding performance of the composite plates.

Catalyst-Free Activation and Fixation of Nitrogen by Laser-Induced Conversion.

Ultrafast N2 fixation reactions are quite challenging. Currently used methods for N2 fixation are limited, and strong dinitrogen bonds usually need to be activated via extreme temperature or pressure or by the use of an energy-consuming process with sophisticated catalysts. Herein, we report a novel laser-based chemical method for N2 fixation under ambient conditions without catalysts, this method is called laser bubbling in liquids (LBL), and it directly activates N2 in water (H2O) and efficiently converts N2 into valuable NH3 (max: 4.2 mmol h-1) and NO3- (0.17 mmol h-1). Remarkably, the highest yields of NH3 and NO3- are 4 orders of magnitude greater than the best values for electrocatalysis reported to date. Notably, we further validate the experimental mechanism by using optical emission spectroscopy to detect the production of intermediate plasma and by employing isotope tracing. We also establish that an extremely high-temperature environment far from thermodynamic equilibrium inside a laser-induced bubble and the kinetic process of rapid quenching of bubbles is crucial for N2 activation and fixation to generate NH3 and NOx via LBL. Based on these results, it is shown that LBL is a simple, safe, efficient, green, and sustainable technology that enables the rapid conversion of the renewable feedstocks H2O and N2 to NH3 and NO3-, facilitating new prospects for chemical N2 fixation.

Material selection for milling fixture of friction stir welding using simulia

Friction stir welding is an innovative welding technique that joins two different materials without the need for consumables. The process involves a profiled probe and shoulder tool that is rotated and plunged between the two workpieces at the interface during the friction stir process. The weld zone undergoes dynamic recrystallization, resulting in a strong bond between the materials. This method offers superior bonding compared to traditional arc welding. In the context of conventional or non-traditional milling machines, friction stir welding is performed. It is necessary to use a milling fixture to attach the plates that need to be butt and lap welded, fixture can be used in underwater FSW. To ensure the workpiece is securely held in place, a fixture or holder is necessary. In this article, friction-stir welding, and a fixture with a clamping setup are constructed. The fixture is carefully designed to consider the movement of the instrument and workpiece, and it is manufactured using CatiaV6 3D experience software. The fixture is then subjected to three different types of testing using Simulia software. The materials tested include cast iron, die steel, and tool steel. After simulation analysis, the best material for friction-stir welding operations is selected.

Pengenalan cita-cita melalui fun learning untuk meningkatkan minat belajar siswa taman kanak-kanak

This community service aims to enhance students' interest in learning at TK Karitas V, Surabaya, by introducing future goals through fun learning. Early childhood education, which falls within the golden age phase, requires teaching methods that can enhance children's focus, considering that children often face emotional instability during this period. In an effort to achieve this goal, the introduction of future goals is implemented through an engaging and interactive learning model, utilizing playful activities and musical movements to create an enjoyable and meaningful learning experience, thus enhancing the students' learning interest. The method used in this community service is service learning, involving direct interaction with children to create strong emotional bonds and interactions. The results of this community service show changes before and after participation among TK Karitas V students. Students demonstrate increased enthusiasm and eagerness to learn in pursuit of their dreams. Students also show improvement in their ability to understand and interpret aspirations related to their future.

The role of Au and Pd in photocatalytic activation of molecular oxygen: A mechanistic study

Activation of molecular oxygen plays an important role in photocatalytic selective oxidation reactions and complete degradation of organic pollutants. Noble metal cocatalysts are often employed to modulate the activation of oxygen to reach an optimum photocatalytic performance. However, the role of the metal nanoparticles (NPs) still remains unclear and deserves investigation for the design of efficient photocatalysts. Here, Au and Pd NPs are deposited on the TiO2 photocatalyst to study the promotional mechanism of O2 dissociation with the presence of glycerol under irradiation by near-ambient-pressure photoelectron spectroscopy and in-situ spectrometry approaches. While both Au and Pd NPs can dissociate O2 into activated oxygen species, a relatively strong bonds of dissociated oxygen atom is observed on Au NPs than on the Pd NPs. This results in a moderate reduction rate of O2 and eventually favors a mild oxidation reaction process for Au, and a rapid reduction rate of O2 and eventually a deep oxidation reaction process for Pd, respectively.

Thixotropic chitosan hydrogels for biomedical applications: Unravelling the effect of chitosan concentration on the mechanical behaviour

Chitosan hydrogels are highly sought after in biomedical applications due to their biocompatibility, non-toxicity, and tunable mechanical properties. Nevertheless, achieving stable hydrogels with the required mechanical strength remains a notable obstacle. In this study, we prepared chitosan hydrogels with enhanced stability using minimal concentrations of glutaraldehyde to mitigate toxicity risks. The resulting hydrogel system is characterized by strong covalent bonds formed through imine and hydrogen bonding, facilitated by the aldehyde groups of glutaraldehyde. Rheological analyses reveal the viscoelastic properties of the hydrogels, showcasing stable gel-like structures with shear-thinning behavior, which are further enhanced with increasing chitosan concentration. Our observation demonstrates that the complex shear moduli of 0.5 - 1.5 w/v% chitosan hydrogel ranged between 3.08 kPa and 8.5 kPa, closely matching the shear moduli of the brain and connective tissues. The shear moduli obtained for the 2 w/v% (10.2 kPa) and 2.5 w/v% hydrogels (11.34 kPa) conform to the shear moduli of liver, fat, relaxed muscle, and breast gland tissue. Thixotropic studies reveal good structural recovery behaviour in the hydrogels. The swellability of 2 w/v% and 2.5 w/v% hydrogels (50–70 %) suggests their suitability for bone tissue engineering, with moderate porosity required for bone growth (60–75 %). Moreover, the yield stress values of 0.5 - 1.5 w/v% hydrogels satisfy the requirements for soft tissue engineering, while those of 2 and 2.5 w/v% match the requirements for bone tissue engineering. Our findings suggest that chitosan hydrogels of varying concentrations (0.5–2.5 % w/v) hold promise for a range of biomedical applications, including tissue engineering for brain, nerve, soft, and bone tissues, and wound dressing. This research addresses the pressing need for stable chitosan hydrogels with tailored mechanical properties, potentially offering solutions to challenges in biomedical materials design.

Mn-S chemical bond mediated Z-scheme photocatalyst boosting efficient H2 evolution with apparent quantum yield exceeding 32% under visible light

Developing a highly effective solar-to-H2 conversion system is a promising strategy for carbon neutrality. Here, we report a chemically bonded Z-scheme photocatalyst by specifically linking the conduction band site of ZnIn2S4 with the valence band site of Mn0.3Cd0.7S1-x. Deviates from the typical van der Waals interactions between two semiconductors, the in-built robust binding force (Mn-S bond) and charge transfer channel facilitates the electron mobility, minimizes detrimental deep charge trapping, and prolongs the active charge lifetime from 983 ps to 4250 ps. The sulfur vacancies in Mn0.3Cd0.7S1-x are partially refilled by atoms of the same element in ZnIn2S4 during the in-situ formation of heterojunctions, which promotes and solidates the establishment of interfacial chemical bonds. The optimal photocatalyst achieves a high quantum efficiency of 32.71 % at 420 nm. This study offers a new insight into the development of Z-Scheme heterojunctions via a synergistic approach involving doping, vacancy filling and strong interfacial chemical bonds.

Survey Study of the Importance of Cultural Diplomacy of Indonesia in Azerbaijan

Since the existence of the Embassy of the Republic of Indonesia in Azerbaijan, Indonesia began to strengthen its relations with Azerbaijan massively through cultural diplomacy through performances as well as cultural events. Furthermore, the cultural diplomacy of Indonesia and Azerbaijan is also conducted through cultural scholarship, the study of the Indonesian language, as well as learning its dances in the embassy for Azeri students. This study aims to describe the importance of Indonesia's cultural diplomacy in Azerbaijan by employing a descriptive quantitative research method in which the data is obtained through the primary survey conducted by the author. The study found that utilising culture in Indonesia’s diplomatic practices in Azerbaijan is a paramount thing to building a strong bond and trust between countries, especially at the young age of the embassy existence in Azerbaijan.

Cow and calf-level factors associated with nursing behaviours in beef cattle during the 24-hours following an assisted calving

Nursing behaviour is essential following parturition to ensure transfer of passive immunity and the development of a strong cow-calf bond. One factor that could modify nursing behaviour is dystocia; however, little work has documented this effect. The objective of this study was to: 1) characterize nursing be­haviour in beef cattle for 24 hr following an assisted calving, 2) identify cow- and calf-level factors associated with nursing behaviours, and 3) determine the effects of cow and calf behav­iours on the transfer of passive immunity.

Formation of Organic Monolayers on KF-Etched Si Surfaces

Silicon is the most commonly used material in the microelectronics industry, due to its inherent advantages of high natural abundance, low cost, and high purity, coupled with the chemical and electrical stability at the interface with its oxide. For molecular electronics applications, oxide-free Si surfaces are widely used because of the relative ease of removing the oxide (SiOx) by chemical means, yielding a surface which forms strong covalent bonds with a wide range of chemical functional groups; another advantage is that these surfaces remain oxide-free in the absence of oxidising agents. Standard procedures require the use of either HF, NH4F, or a mixture of both as the etching solution; however, these two chemicals are highly corrosive and toxic, posing a significant risk to the experimentalist. Here, we report that for silicon wafers etched by using potassium fluoride, a less toxic chemical, the resulting surface is free of oxides and can be functionalized by self-assembled monolayers of 1,8-nonadiyne. To demonstrate this, Si/SiOx wafers were etched by using either KF or NH4F, followed by hydrosilylation with 1,8-nonadiyne and a click reaction of the terminal alkyne with azidomethylferrocene. The surface coverages and electron transfer kinetics of the ferrocene-terminated KF-etched surfaces are comparable to those formed by acidic fluoride etching procedures. This is the first study comparing the differences between surfaces functionalized by self-assembled monolayers of 1,8-nonadiyne which were etched by KF and NH4F. KF could be used as a replacement chemical for etching silicon wafers when a less corrosive and toxic chemical is required.

Regulating sulfur migration and transformation in low water-binder ratio cementitious system incorporating phosphogypsum aggregate: Environmentally friendly clean materials

The paper aims to clarify the regulation mechanism of sulfur migration and transformation in a low water-binder ratio system incorporating phosphogypsum aggregate (LWC-PG). Firstly, the combination of S-containing adhesive material and phosphate gypsum aggregate can reduce the migration of sulfate ions (SO42−) in the phosphate gypsum aggregate. The reaction mechanism and macro and micro properties of LWC-PG are characterized by universal testing machine, low field nuclear magnetic field, isothermal calorimeter, XRD diffractometer, scanning electron microscope and nano-indentation. The results show that the calcium sulfoaluminate cementitious system (CSA) is compatible with PG. The results show that CSA is compatible with PG, and the 28d strength of 80 % phosphogypsum is 83.4 MPa, which can maintain the required strength for high-performance concrete. Secondly, the sulfides in PG react with C4A6S in CSA, resulting in the formation of ettringite that coats the surface of the C–S–H gel, thereby retarding the hydration rate of the slurry. However, due to the presence of phosphate gypsum aggregate, the reaction continues, enhancing the hydration of sulfate cement. Moreover, the interfacial transition zone between the PG and matrix exhibits a strong bond and shows no significant signs of deterioration. Lastly, when using 80 % phosphogypsum aggregate instead of natural sand and gravel to produce 100 m3 of concrete, 42 t of phosphogypsum aggregate can be used, which reduces the consumption of natural sand and gravel by 61.4 t, decreases energy consumption by 3070 MJ, reduces CO2 emissions by 178.06 kg, SO2 emissions by 0.37 kg, NOX emissions by 0.25 kg, and dust emissions by 0.087 kg. Life cycle evaluation demonstrates that the production of LWC-PG is associated with low carbon emissions and environmental friendliness, which significantly reduces environmental burden. This is of significant research importance for solid waste management and energy-saving and carbon reduction efforts.

Study on the characteristics of Napier grass fibre reinforced porcelain filler particulates poly lactic acid matrix biocomposite

This study investigates the complex properties of a novel biocomposite by a conventional process, which is composed of poly (lactic acid) (PLA) as the matrix, porcelain particles as fillers, and Napier grass fibre as reinforcement. The primary objective was to evaluate the mechanical, crystalline, water absorption, morphological, and antibacterial properties of the biocomposites in relation to the individual components and their synergistic impacts. When 25 g porcelain particles were added to PLA with Napier grass fibre, mechanical tests demonstrated a 25% increase in tensile strength (maximum tensile strength of 39.76 MPa) and a 30% increase in flexural strength (maximum flexural strength of 41.29 MPa). Scanning electron microscopy (SEM) revealed a strong interfacial bond between the fibre and matrix, with porcelain particles serving as bridges to facilitate stress transmission. The biocomposite exhibited reduced water absorption due to the inherent hydrophobic nature of porcelain, which enhances its resistance to bacterial growth. The study demonstrates that combining Napier grass fibre with porcelain filler particles synergistically enhances the properties of PLA, creating a viable biocomposite material suitable for use in packaging, automotive, and sustainable building industries.

N2 cleavage by silylene and formation of H2Si(μ-N)2SiH2

Fixation and functionalisation of N2 by main-group elements has remained scarce. Herein, we report a fixation and cleavage of the N ≡ N triple bond achieved in a dinitrogen (N2) matrix by the reaction of hydrogen and laser-ablated silicon atoms. The four-membered heterocycle H2Si(μ-N)2SiH2, the H2SiNN(H2) and HNSiNH complexes are characterized by infrared spectroscopy in conjunction with quantum-chemical calculations. The synergistic interaction of the two SiH2 moieties with N2 results in the formation of final product H2Si(μ-N)2SiH2, and theoretical calculations reveal the donation of electron density of Si to π* antibonding orbitals and the removal of electron density from the π bonding orbitals of N2, leading to cleave the non-polar and strong NN triple bond.