Average Moment Research Articles

Flow dynamics of train under turbulent inflow at different crosswind yaw angles

The turbulence intensity and yaw angle of crosswinds exert a substantial impact on the aerodynamic characteristics of trains traveling in windy regions. It is urgent to study how the yaw angle and turbulence intensity of incoming flow jointly affect the aerodynamic characteristics of the train and the corresponding flow field under turbulent crosswind. A high-speed train scaled at a ratio of 1/8 of its actual size at different yaw angles was investigated. Three inflow conditions were adopted, including uniform inflow, Iu = 0.05 inflow, and Iu = 0.2 inflow (Iu is turbulence intensity). The turbulent inflow was generated by the synthetic eddy method. The instantaneous and time averaged characteristics of aerodynamic loads and pressure loads of the train were analyzed. The vortex structures, vorticity, swirling strength, mean velocity, reverse flow, and Reynolds stresses are analyzed to explore the flow pattern and flow evolution. The results found that the fluctuation of the aerodynamic loads, the average side fore, and the average rolling moment of the train are remarkably enhanced under turbulent inflow. These results stem from the alterations in the flow field around the train induced by turbulent inflow, consequently leading to variations in surface pressure on the train. As the turbulence intensity of the inflow increases, the stability of the vortex structures decreases, and the position of the large-scale vortex structure has been changed. Moreover, the yaw angle (β) exerts a more significant influence on the vortex structure's flow pattern on the leeward side compared to the inflow turbulence intensity.

Recurrence Times of Large Earthquakes: Assimilating the Effect of Seismic Coupling into a Renewal Model

ABSTRACT A renewal model for estimating recurrence times of large earthquakes is presented, which allows one to assimilate data from paleo, historic, and instrumental earthquake data as well as geodetic information in a simple and efficient way using three parameters: the Richter b-value, the mean recurrence time μT of paleo and historic earthquakes, and the seismic coupling coefficient χ. The core of the model is a state variable with linear drift in time reflecting Reid’s elastic rebound theory, decorated with random fluctuations modeling small and intermediate earthquakes. Furthermore, it is assumed that a fraction between 0% and 100% of the average seismic moment is released seismically, and the remaining part corresponds to aseismic processes such as creep. The model extends former renewal models of Matthews et al. (2002) and Zöller et al. (2008). Results for different regions indicate overall good performance and thus suggest that the model provides physically motivated constraints for recurrence time estimations in contrast to the standard fitting of a few data points to an assumed distribution.

Synthesis and examination of alkoxycyanobiphenyl mesogens with a single fluorine atom at specific locations in the tail

ABSTRACT Selective fluorination is a well-established technique to tailor and improve many of the physical properties of liquid crystals. Cyanobiphenyls are among the best-known and understood thermotropic liquid crystals and have served admirably as a testbed for structural modifications that can eventually be extended to other classes of liquid crystals. As such, and expanding on our earlier work, in the present study of the alkoxycyanobiphenyl M series, the individual tail sites of both 4’-(butoxy)[1,1’-biphenyl]-4-carbonitrile (M12) and 4’-(pentyloxy)[1,1’-biphenyl]-4-carbonitrile (M15) were selectively monofluorinated in order to examine the influence on the phase behavior. These fluorinated compounds were synthesized using epoxidation, regioselective epoxide opening and deoxyfluorination chemistry. In all the fluorinated compounds in both series a monotropic nematic phase was found in the cooling cycle. It was observed that as the fluorine atom on the tail moves closer to the core, the compounds exhibited a metastable room temperature nematic mesophase, but recrystallization invariably occurred. Both enantiomers of 4’-(2-fluorobutoxy)[1,1’-biphenyl]-4-carbonitrile were synthesized in high enantiomeric purity by regioselective opening of chiral epoxide intermediates followed by deoxyfluorination, as established by chiral high-performance liquid chromatography, and their phase behaviors were determined. Moreover, the average dipole moments of the synthesized fluorine substituted derivatives were also calculated.

Wind-Induced Response Assessment of CAARC Building Based on LBM and FSI Simulation

It is very important for the wind-resistant design of high-rise buildings to assess wind-induced vibrations efficiently. The Lattice Boltzmann Method-based Large Eddy Simulation and Fluid–Structure Interaction techniques are used to identify the surface wind pressure and wind-induced dynamic response of a CAARC standard high-rise building. Compared with wind tunnel tests, a detailed analysis of the accuracy of simulated wind pressures and base moments of the CAARC model are discussed under multiple wind direction angles. The differences between one-way and two-way Fluid–Structure Interaction simulations are compared under two different reduced wind velocities. The research results show that the simulated mean surface wind pressures of building under seven wind direction conditions have an error within 15% compared to probe measurements, and the average and root mean square base bending moments agree well with the wind tunnel tests. The top transverse wind-induced vibrations of the buildings are significantly larger when the reduced wind velocity reaches 4.6, indicating that aerodynamic damping effects on structural responses should not be overlooked. The research findings of this article provide valuable technical references for the application of LBM methods in the wind load effect assessments of high-rise buildings.

Investigating the effectiveness of CFRP strengthening in improving the impact performance of RC members

Rising global rail infrastructure expansion has increased accidents involving train derailments. Reinforced concrete (RC) elements require impact-resistance enhancement to prevent structural damage or failure. While extensive research has analyzed CFRP-strengthened concrete columns under dynamic loading, further understanding of CFRP's impact on RC members is needed. Considering dynamic factors, this study investigates CFRP-RC components' performance under asymmetric impact. Components wrapped in one, four, or six CFRP layers underwent high-energy asymmetric lateral impact testing to obtain deflection-time curves. Results showed that multiple CFRP layers significantly improved impact resistance by increasing plateau force, reducing maximum deflection to 42%, and shortening duration. Longitudinal-circumferential bonding conferred better reinforcement than other arrangements. However, multiple CFRP layers increased fracture susceptibility due to severe concrete damage. An equation was derived from dynamic equilibrium principles. Finite element modeling validated experimentally was used to simulate lateral impact. Impact force, deflection, and bending moment over time were compared. Impact resistance, flexural capacity, plastic deformation, and energy absorption were also examined. Internal force distribution and development were analyzed. A simplified calculation estimated maximum deflection. CFRP reinforcement methods' effects were examined. Results indicate CFRP elevates plateau impact force and average bending moment while significantly decreasing deflection and duration, greatly enhancing impact resistance and flexural bearing capacity.

Experimental study of precast concrete walls using bamboo as alternative reinforcement

The public's demand for simple, livable houses means that material studies to support this continue to be carried out today, starting from using natural materials such as bamboo as precast concrete walls. This study aims to conduct an experimental study using bamboo rope from the Gigantochloa Apus variety as an alternative reinforcement for precast concrete walls. Research was carried out on 12 precast concrete wall test specimens, and the flexural properties, flexural strength, and crack patterns were formulated when subjected to a quasi-static load concentrated in the middle of the span. The concrete slab measures 600800 mm with a 50 and 75 mm thickness. The three configurations of bamboo bones used include (1) Gedhek-type woven bamboo slats, (2) bamboo slat type, and (3) Sasak-type woven bamboo slats. The research results show that Sasak-type woven bamboo slat reinforcement is the most effective alternative reinforcement. The behavior of the test specimen shows a ductile failure pattern similar to conventional reinforced concrete. The maximum moment capacity achieved is 1.5 to 2.2 times greater than the theoretical nominal moment capacity. Meanwhile, the behavior of test specimens with conventional plate-type woven bamboo slat reinforcement showed sudden and brittle failure due to slippage at the bond between the bamboo reinforcement and concrete. The average maximum moment from the test results is 60% of the theoretical nominal moment. The results of this research recommend that woven bamboo slats of the conventional plate reinforcement type are less effective as alternative reinforcement if they are not given special treatment to increase their adhesion to concrete. Gedhek-type woven bamboo slats are not effective as alternative reinforcement because they cause separation of the top and bottom parts of the woven concrete, thereby reducing the integrity of the cross-section and causing the cross-sectional capacity to be relatively small.

Hybrid data-driven and physics-based modeling for viscosity prediction of ionic liquids

Viscosity is one of the most important fundamental properties of fluids. However, accurate acquisition of viscosity for ionic liquids (ILs) remains a critical challenge. In this study, an approach integrating prior physical knowledge into the machine learning (ML) model was proposed to predict the viscosity reliably. The method was based on 16 quantum chemical descriptors determined from the first principles calculations and used as the input of the ML models to represent the size, structure, and interactions of the ILs. Three strategies based on the residuals of the COSMO-RS model were created as the output of ML, where the strategy directly using experimental data was also studied for comparison. The performance of six ML algorithms was compared in all strategies, and the CatBoost model was identified as the optimal one. The strategies employing the relative deviations were superior to that using the absolute deviation, and the relative ratio revealed the systematic prediction error of the COSMO-RS model. The CatBoost model based on the relative ratio achieved the highest prediction accuracy on the test set (R2 = 0.9999, MAE = 0.0325), reducing the average absolute relative deviation (AARD) in modeling from 52.45 % to 1.54 %. Features importance analysis indicated the average energy correction, solvation-free energy, and polarity moment were the key influencing the systematic deviation.

Promoting electrocatalytic nitrogen reduction by introducing low-spin sites in ferromagnetic single-atom alloys

In ferromagnetic single-atom alloys, the average electron spin moment P of dopants, a new descriptor, has volcano relationships with the e-NRR theoretical activity and selectivity.

Effect of alternating electric field induced by cold atmospheric plasma on conformation and function of interleukin-6

Cold atmospheric plasma (CAP) is considered to be a very promising cancer treatment method due to its “selective” killing effect on cancer cells. The CAP can inhibit tumor inflammatory responses and activate the immune system by reducing the expression of the key inflammatory factor Interleukin-6 (IL-6). However, the influence of the strong alternating electric field induced by CAP on the conformation and function of IL-6 remains unclear. In this study molecular dynamics simulation is used to investigate the effects of alternating electric fields with different frequencies and intensities on the conformation of IL-6. We statistically analyze the root mean square fluctuations, root mean square deviation, secondary structural alterations, and dipole moment changes of IL-6 under different electric field parameters. Furthermore, molecular docking is utilized to assess the influence on the receptor-binding process. The results show that when the electric field frequency is below 30 MHz and the intensity exceeds 0.5 V/nm, the average dipole moment of IL-6 increases, leading to changes in the rigid regions at the C-terminus which maintain structural stability. Specifically, the salt bridges that stabilize the long helices rupture, and the number of α-helices decreases. The docking outcomes reveal that the distance between the key binding residues of the conformationally altered IL-6 and its receptor increases, thereby disrupting the normal binding process and potentially impairing its normal biological functionality. This study explains the internal interaction mechanism of CAP-induced electric fields affecting IL-6-related biological effects at the micro level, and provides important theoretical basis for optimizing parameters in the practical application of CAP in tumor inflammation treatment and the development of effective cancer therapy strategies.

Controlled dynamic variation of interfacial electronic and optical properties of lithium intercalated ZrO2/MoS2 vdW heterostructure

Efficient strategies for modifying the characteristics of van der Waals (vdW) layered materials in a precise and reversible mode remain challenging. Our suggested method for customization entails the implementation of layer-sliding and intercalation. In this work, a norm-conserving approach within the context of density functional theory has been used to examine the electronic and optical properties of two-dimensional (2D) van der Waals heterostructure (vdWHS), which is modeled by using 2D zirconium dioxide (1T-ZrO2) and molybdenum disulfide (1T-MoS2) monolayers of similar phase. Both contributing monolayers have similar lattice structures, with a minimum lattice mismatch of 0.83 %, and have corrugation on both sides that can successfully retain foreign species at the vdW-gap. In the next step, interfacial engineering through Li-intercalation and layer-sliding was employed to modify physical properties of the vdWHS. It is the worth mentioning that a narrow bandgap of 0.102 eV (0.22 eV) has been observed in the unintercalated ZrO2/MoS2 vdWHS when employing PW-LDA (hybrid-functional). Li-intercalation and sliding process significantly influenced the electronic properties of the studied vdWHS. Furthermore, un-slided and fully-slided Li-intercalated vdWHS exhibit an increase in the vdW-gap by 3.78 % and 27.14 %, respectively, as compared to unintercalated vdWHS. To further understand the electrical behaviour at the interface of contributing monolayers, a comparative study has also been made for the variation in the planar average charge density difference, charge transfer, and interface dipole moment for unintercalated and intercalated vdWHS. In the unintercalated vdWHS, the calculated values of ΔQ and μ(z) provide evidence of significant charge transfer from 1T-ZrO2 to 1T-MoS2 before sliding, whereas in the fully-slided vdWHS, there is 80.11 % more charge transfer from 1T-MoS2 to 1T-ZrO2. Li-intercalation increases the magnitude of ΔQ (by 90.27 %) near 1T-MoS2, indicating a sufficient quantity of charge transfer from the 1T-MoS2 monolayer. The results of the anisotropic analysis show that the calculated in-plane and out-of-plane components of the real and imaginary parts of the dielectric function differ significantly. The optical absorption and energy losses of Li-intercalated vdWHS experience a substantial decrease of about 90 % and 50 %, respectively, as compared to unintercalated vdWHS. Our employed method promotes the notion that interfacial engineering through simultaneous layer-sliding and intercalation approach can be used to regulate and modify the physical properties of 2D insulator/metal based vdWHS.

Finite source properties of large strike-slip earthquakes

SUMMARY Earthquake ruptures are complex physical processes that may vary with the structure and tectonics of the region in which they occur. Characterizing the factors controlling this variability would provide fundamental constraints on the physics of earthquakes and faults. We investigate this by determining finite source properties from second moments of the stress glut for a global data set of large strike-slip earthquakes. Our approach uses a Bayesian inverse formulation with teleseismic body and surface waves, which yields a low-dimensional probabilistic description of rupture properties including the spatial deviation, directivity and temporal deviation of the source. This technique is useful for comparing events because it makes only minor geometric constraints, avoids bias due to rupture velocity parametrization and yields a full ensemble of possible solutions given the uncertainties of the data. We apply this framework to all great strike-slip earthquakes of the past three decades, and we use the resultant second moments to compare source quantities like directivity ratio, rectilinearity, average moment density and vertical deviation. We find that most strike-slip earthquakes have a large component of unilateral directivity, and many of these earthquakes show a mixture of unilateral and bilateral behaviour. We notice that oceanic intraplate earthquakes usually rupture a much larger width of the seismogenic zone than other strike-slip earthquakes, suggesting these earthquakes may often breach the expected thermal boundary for oceanic ruptures. We also use these second moments to resolve nodal plane ambiguity for the large oceanic intraplate earthquakes and find that the rupture orientation is usually unaligned with encompassing fossil fracture zones.

Moment arms of the coracobrachialis and short head of biceps following a Latarjet procedure: a modeling study

BackgroundThe Latarjet procedure transfers the coracoid process to the anterior glenoid. This prevents recurrent anterior humeral dislocation but alters the origin of the coracobrachialis (CBR) and short head of bicep (SHB). The impact of this alteration on the moment arms of these muscles has not been examined. MethodsThe Newcastle Shoulder Model was updated with 15 heathy cadaveric bone models to create customized shoulder models. The CBR and SHB muscles were attached to the anterior glenoid via an elliptical wrapping object. Muscle moment arms were calculated for abduction, forward flexion, scapula plane elevation and internal rotation with 20⁰ and 90⁰ abduction. Statistical comparison between native and Latarjet moment arms was performed using spm1D. ResultsBy transferring the origin of CBR and SHB to the anterior glenoid, both muscles had extension moment arms during glenohumeral elevation in coronal, sagittal, and scapular plane. Their average moment arms during abduction (CBR: -30.4±3.2mm; SHB: -29.8±3.0mm) and forward flexion (CBR: -26.0±3.1mm; SHB: -26.2±3.2mm) suggested that their role after Latarjet changed, compared with that of their role in a native shoulder (p<0.001). At higher abduction levels both the muscles had higher internal rotation moment arms compared to the native shoulder. ConclusionThe Latarjet procedure affected the moment arms of the CBR and SHB. Both muscles had increased extension and internal rotation moment arms at higher degrees of elevation, compared to the native shoulders, this suggests that these muscles act as dynamic stabilizers after Latarjet.

Palaeomagnetic field intensity measurements from the 2.6 Ga Yandinilling dyke swarm (Western Australia)

SUMMARY Precambrian palaeointensity measurements provide fundamental constraints on the evolution of the deep Earth. Core evolution models predict trends in dipole moment on billion-year timescales that can be tested by palaeomagnetic records. Here, we report new palaeointensity results from the recently identified ∼2.62 Ga Yandinilling dyke swarm of the Yilgarn Craton, Western Australia, and consider them alongside published measurements spanning 500 Myr across the late Archaean to earliest Proterozoic. Rock magnetic and scanning electron microscopy analysis confirm that the magnetic mineralogy is fine-grained magnetite, appearing mostly as exsolved lamellae with ilmenite. Six sites produced acceptable palaeointensity estimates from thermal and microwave IZZI protocol Thellier experiments and from double-heating technique Shaw experiments. These site mean values of 9–26 µT translate to virtual dipole moments of 11–44 ZAm2 that are considerably lower than today's dipole moment of ∼80 ZAm2 and the value predicted for this time period by some thermal evolution models. Their average (median = 41 ZAm2) is, however, similar to the long-term average during both of the intervals 2300–2800 Ma (median = 44 ZAm2; N = 103) and 10–500 Ma (median 41 ZAm2; N = 997). While there is little evidence for a substantial net change in average dipole moment between the late Archaean and Phanerozoic, there is preliminary evidence that its variance has increased between the two intervals. This lower variance more than two billion years ago supports the idea that the geodynamo, even while not producing a stronger magnetic field, was more stable on average at the Archaean–Proterozoic transition than it is today.

Applied and computational investigation of plasticizing effects of dibutyl maleate on polymethyl methacrylate acrylic resin material

In this study, the amount of change in the glass transition temperature (Tg) of PMMA was analyzed by DSC by adding different ratios of dibutyl maleate (DBM) plasticizer to polymethyl methacrylate (PMMA), which is used as the main ingredient of prosthetics in dentistry. For this, liquid DBM was added to powdered PMMA at a rate of 2, 5, 8 and 15 % by mass, and polymerization was carried out at 100 °C. Mechanical tests such as impact resistance, transverse resistance and maximum flexion tests were applied to these prepared mixtures. It was observed that there was a significant parallelism between the Tg values calculated from the DSC curves and the mechanical tests. The Tg value of PMMA was reduced by approximately half with the addition of DBM plasticizer. Additionally, the chemical interaction between PMMA and DBM was analyzed in the light of the Density Functional Theory (DFT) calculations. The binding energy for the mentioned interaction was determined as 1.591 eV. After both species interacted with each other, the glass transition temperature of the formed complex system was theoretically also predicted through the quantitative structure-property relationship (QSPR) model. For theoretical prediction of Tg, the molecular traceless quadrupole moment Θ and the molecular average hexadecapole moment Φ, are used. The change determined as experimental in glass transition temperature as a result of the interaction between PMMA and DBM was supported with theoretical calculations. Experimental and theoretical data are in good agreement.

Neutron-powder-diffraction studies of the nuclear and magnetic structure of the double-perovskite CaxSr2−xWMnO6 (x = 0.5, 1.0, and 1.5)

The nuclear and magnetic structures of CaxSr2−xWMnO6 (x = 0.5, 1.0, 1.5) have been investigated by neutron diffraction at 295, 30 or 40 K, and 4 or 5 K. The compounds crystallized in the monoclinic symmetry with a space group P21/n. The nuclear structure consists of ordered WO6 and Mn2+O6 octahedral frameworks, with lattice constant a decreasing more rapidly than b with increasing Ca content. No structural change was found around the magnetic transition temperature, although the Mn octahedron below the magnetic order temperature exhibited a slightly compressed Jahn–Teller distortion (0.1–0.3 Å) along the c axis. A standard magnetic model was used to solve the magnetic structure, with the Mn magnetic moments ferromagnetically coupled along the a axis and anti-ferromagnetically coupled along the b and c axes, resulting in a magnetic propagation vector of k = (0,1/2, 1/2) and a magnetic superlattice of 1a × 2b × 2c. In each crystallographic cell, the Mn1–Mn2 atoms are antiferromagnetically configurated, compensating the total moment to zero by symmetry. A layer-type magnetism along the (111) crystallographic plane was confirmed to couple antiferromagnetically between these planes and ferromagnetically within them. The magnetic structure refinement confirmed an average Mn moment of 4.5 μB. Also, it reveals that the collinear magnetic Mn configuration has three possible spin orientations, namely, (with their standard deviation) [μx = (3.3 ± 0.4) μB, μy = (2.5 ± 0.3) μB, μz = (−0.7 ± 0.7) μB], [μx = (3.0 ± 0.4) μB, μy = (0.5 ± 0.2) μB, μz = (−2.8 ± 0.2) μB, and [μx = (−1.8 ± 0.4) μB, μy = (2.9 ± 0.2) μB, μz = (−2.4 ± 0.3) μB. The first configuration is estimated to be the ground state, while the other magnetic configurations are an optimum local value derived from the refinements. Combined with the density functional theory calculations, these experimental results confirm a high-spin state Mn2+ (d5) electron configuration.

Wave-impact forces and moments due to random waves on a jacket-type platform for different relative submergence of the deck

Force and moment measurements due to wave impacts were conducted on a jacket platform model under six distinct relative deck submergence conditions. The water depth was carefully chosen to facilitate scenarios ranging from sufficient deck air gaps to partial and complete submergence. For the purpose of our analysis, we focused on peak and average peak wave force and moment values. The study uncovers that the peak wave force towards the shore can escalate to 1.5 times the peak wave force towards the sea. Moreover, the ratio of the peak shoreward force to the average peak shoreward force fluctuates between 3 and 4, contingent upon the relative water level at the deck base and the prevailing wave condition. Remarkably, the peak upward wave force on the deck can reach 5 to 7 times the peak inline wave force. A review of existing guidelines suggests a significant need to enhance research regarding the air gap between the deck and the still water level (SWL), as well as its effect on global and local wave forces and moments on the structures. Our finding establishes that the relative water level from the base of the deck is a crucial parameter in the design process of these structures. This study presents a more in-depth understanding of the physical mechanisms at play by utilizing a realistic jacket platform model. It serves as an initial exploration into the influence of air gap and relative water depth on wave-impact forces and moments. The results obtained from this study shed light on optimal design strategies for jacket-type offshore drilling platforms, considering green water effects. This understanding will enhance the life expectancy and survivability of such platforms.

PENGARUH SUBSTITUSI CANGKANG KERANG DARI ENDE NTT TERHADAP KUAT TEKAN DANKUAT LENTUR BETON fc’= 19,3 MPa

The use of concrete for basic construction materials today is indeed increasing rapidly along with the development of construction construction.Only a concrete quality of 19.3 MPa (fc '= 25 MPa) was considered in this study. Since cement, aggregates, sand and water are extracted from nature, they must be limited. So in this study using additional material clam shells. One of them is shells, shellfish waste or shells are usually only used as decorations or toys so that there is still a lot of waste wasted. Inside the shell, the clam contains pozzolan chemical compounds, namely lime (CaO), aluminum oxide and silica. It can be expected to improve the quality of concrete.&#x0D; As a result of compressive strength test by changing the clamshell to 0%, 10%, 20%, 30%, 40% and 50%, the average compressive strength value of 0% (ordinary concrete) was 15.81 MPa. The addition of a 10% clam shell results in an average compressive strength value of 20.58 MPa. For the addition of clam shells by 20% obtained an average compressive strength value of 23.37 MPa. 30% yields an average compressive strength of 40.31 Mpa, to 40% of 29.12 Mpa. As for the addition of 50% clam shells, the average compressive strength value is 24.79 Mpa. Thus it can be concluded that the addition of clam shells 30% compressive strength value is higher than the compressive strength value of concrete with the addition of clam shells 0%, 10%, 20%, 40%, and 50%The flexural strength test value in terms of the maximum average moment on the beam for each variation of the test specimen is maximum moment value 75.02 kN.m for 0% variation, maximum moment value 62.52 kN.m for 10% variation, maximum moment value 68.77 kN.m for 20% variation, maximum moment value for 30% variation 62.52 kN.m, 40% variation at maximum moment value of 62.52 kN.m. Therefore, the percentage of specimens that can withstand the highest load in the flexural strength test is 0% and the maximum moment value is 75.02 kN.m.

ANALYSIS OF FINGER-JOINTS IN GLASS FIBER-REINFORCED POLYMER (GFRP) COMPOSITE GLUED LAMINATED TIMBER BEAMS

The objective of this paper was to evaluate the effect of finger-joint reinforcement on thebending strength and stiffness of glulam beams made from high-density Eucalyptus spp. glued with resorcinol-formaldehyde adhesive.Six glulam beams were tested: three reinforced with glass fiber-reinforced polymer(GFRP) and three unreinforced for comparison. The GFRP was placed between the last two laminatesand at the bottom edge of theglulam only in the finger-joint position. The stiffness and strength of glulam beams were evaluated using static bending tests, which showed that the use of GFRP reinforcement resulted in a gain of more than 100% in average ultimate bending moment and about 10% in average bending stiffness. Tocalculate the theoretical bending stiffness and normal stresses, a theoretical analysis of beam bending was performed using the transformed section method, which showed agreement with the experimental results.

Bonding mechanism and magnetic ordering in Laves phase λ1−MgCo2 intermetallic compound from theoretical and experimental studies

In the present work we have studied the bonding mechanism and magnetism in a hexagonal λ1−MgCo2 Laves phase intermetallic formed at rA/rB= 1.280. Ab initio theoretical calculations for MgCo2 using the projector-augmented wave method implemented in the VASP code showed that Mg carries a formal charge +1.7 |e| while Co atoms are also positively charged with around +0.7 |e| being donated to establish the interatomic covalent Co-Co bonding in a three-dimensional network of Co tetrahedra. MgCo2 is a metallic conductor with ferromagnetic properties and TC=303 K. Neutron Powder Diffraction study showed a collinear ordering of the Co moments, their alignment along the c-axis of the hexagonal unit cell with an average moment of 1.51(2) μB/atom Co. Ab initio computational studies indicate that the Co moments reach the experimentally observed value approx.1.5 μB when the unit cell volume exceeds 160 Å3 (average Co-Co distances 2.43 Å).

Application of scaled boundary finite element method in failure probability estimation of square nanographene sheet

In recent years, so much attention has been drawn to the field of nano computational material science. Due to the extensive applications of nanographene sheets in various industries such as aerospace industry, fracture analysis of square nanographene sheets is of crucial importance. Stochastic analysis is widely applied in fracture mechanics because it helps the results to be more realistic. In the present work, probabilistic fracture analysis of nanographene sheets is done using scaled boundary finite element (SBFEM) that is a novel semi-analytical method. In order to apply the stochastic method, we need to select certain statistical parameters, the ones considered here include crack length and failure stress. The results using the stochastic response method are compared with those of the Monte Carlo, which shows good agreement. Average, variance, third and fourth moments of stress and the fracture probability are calculated for all the bonds in two states of crack angle 0°, 90°. The results indicate that the maximum crack-tip fracture probability for central crack θ = 90° is 95%, while for θ = 0° equals 58%. For central crack θ = 90°, the failure probability in crack tip bonds, bonds adjacent to the crack edge and other bonds equal 95%, 88% and 65%, respectively. For nanographene sheet having the central crack θ = 90°, probabilistic density function is Gaussian, which reaches the highest point at the displacement being 0.990 pm. The third moment of the stress turned out to be zero, which shows that the input uncertain variables are all normal. The results obtained from computing the failure probability of all the bonds indicates that the highest failure probability is in the tip and edges of the crack. The stochastic fracture sensitivity versus crack length is calculated which shows that the maximum sensitivity in central crack happens when θ = 90° and crack length ranges between 0.3 and 0.4.