Loading Method Research Articles

A monitoring method for wind loads exerted on offshore gravity wind turbine through optimised mathematical model

The actual load borne by a structure throughout its entire lifecycle, such as the wind load on fixed offshore wind turbines, is unknown. This leads to significant differences between the actual life of a structure and the fatigue analysis results during the design phase. Wind-load identification can effectively obtain the wind load borne by a fixed fan throughout its lifecycle. However, measurement noise and an ill-posed mathematical model affect the identification accuracy and stability. In this study, the optimal orientation of the sensor was determined to improve the signal-to-noise ratio according to the stress analysis of the tower structure. A successive addition method (SAM) was proposed to reduce the ill-posedness and dimensions of the mathematical model used for wind-load identification in the frequency domain by removing inefficient strain gauge locations and directions. A distributed successive addition method (DSAM) was developed to improve computational efficiency. The SAM and DSAM were described in detail using a specific case study of an offshore gravity wind turbine; a mathematical model was established through structural harmonic-response analysis. The spectrum superposition method and Dirlik distribution were used to analyse the fatigue damage of the wind-power tower. Several numerical examples were used to demonstrate the effectiveness of the SAM and DSAM. The simulation results demonstrated that the SAM and DSAM can completely eliminate the ill-posedness of mathematical models. In addition, the results of the structural fatigue analysis using the identified wind loads were extremely similar to the fatigue analysis results using the original wind loads, with an error of less than 3%.

Superimposed frequency adaptive droop control strategy with balanced battery state of charge for distributed battery energy system

The conventional droop method for load sharing control in DC microgrid suffers from poor power sharing and voltage regulation, which affects the State of Charge (SoC) balance of distributed Battery Energy Units (BEUs). In this paper, an adaptive droop method based on superimposed frequency is proposed to balance the SoC among distributed BEUs. Accurate current sharing is achieved by using the introduced AC reactive power to adjust the reference voltage according to differences in line resistance. With the proposed SoC balance control method, the SoC balance among BEUs can be guaranteed by the accurate current sharing regardless of the different line resistances in the DC microgrid. In addition, voltage restoration is performed to maintain the average output voltage of the BEU at the nominal value. The effectiveness of the proposed control system is verified by simulation and HIT experimental tests.

EXPERIMENTAL DETERMINATION OF FLOOR PANELS DEFORMABILITY OF A LARGE-PANEL SYSTEM BUILDING AFTER RENOVATION

This paper deals with a field tests of prefabricated reinforced concrete floor panels of a multistory building by the method of hydrostatic loading. Object of study is presented by 3 damaged floor slabs of a 9-storey residential building which was hit during the russian invasion. After renovation of panels using the constructive solution which consists of a reinforced build-up layer in the compressed zone (upper part) and additional external reinforcement in the stretched zone (lower part) connected to each other with the help of anchor connections, a series of tests with water loading were set. For creation of loading an inventory pool was used, which was gradually filled with water at a step of 1kN/m2. Maximum created loading level was 5kN/m2 which corresponds to the operational load. After reaching the maximum load, the panels were left under load for 15 hours and then fully unloaded in steps of 1kN/m2. For each panel two type of tests were established: first when panel had both upper and lower part of reinforcement, and second – when lower reinforcement within steel beams was removed. The idea of dismantling of steel beams connected with previously performed numerical analysis which gave to little difference in deflections of panels for these two cases. Deflection measurements at critical locations along with thorough visual inspection were conducted during the loading and unloading cycles. No damage was observed during the in-situ loading and unloading cycles. Maximum vertical deflection for panel before dismantling of beams lies in the diapason of 1.95-2.1mm and 2.31-2.4mm after they were removed. These results meet the requirements of regulatory restrictions on the maximum deflection equal to 20 mm for this structure. Difference in deflection for two cases doesn’t exceed 20% which allows to abandon the use of lower reinforcement in the form of steel beams in the future. As the size of the pool doesn’t cover the whole panel area, the equivalent uniformly distributed load was also calculated using Lira software. Keywords. Large panel system house, reinforcement, floor panel, method of hydrostatic loading, deflection.

3D printed scaffolds as delivery devices for nanocrystals: A proof of concept loading Atorvastatin with enhanced properties for sublingual route of administration

Increasing the solubility of drugs is a recurrent objective of pharmaceutical research, and one of the most widespread strategies today is the formulation of nanocrystals (NCs). Beyond the many advantages of formulating NCs, their incorporation into solid dosage forms remains a challenge that limits their use. In this work, we set out to load Atorvastatin NCs (ATV-NCs) in a delivery device by combining 3D scaffolds with an “in situ” loading method such as freeze-drying. When comparing two infill patterns for the scaffolds at two different percentages, the one with the highest NCs load was chosen (Gyroid 20 % infill pattern, 13.8 ± 0.5 mg). Colloidal stability studies of NCs suggest instability in acidic media, and therefore, the system is postulated for use as a sublingual device, potentially bypassing stomach and hepatic first-pass effects. An ad hoc dissolution device was developed to mimic the release of actives. The nanometric size and properties acquired in the process were maintained, mainly in the dissolution rate and speed, achieving 100 % dissolution of the content in 180 s. Based on these results, the proof of concept represents an innovative approach to converting NCs suspensions into solid dosage forms.

Antibacterial, Antifungal, and Cytotoxic Potential of PlumbaginLoaded pH-Responsive Vaginal Nanoformulations.

Plumbagin is a naphthoquinone from the roots of the Plumbago species and exhibits anticancer activity. Translational usage of plumbagin in biomedical sciences is restricted due to its poor solubility and bioavailability. Therefore, pH-responsive plumbagin-loaded vaginal nanoformulations with polylactic acid (PLA)-chitosan polymeric coat were fabricated by inotropic gelation technique. Among the four (F1, F2, F3, F4) nanoformulations prepared, F3 exhibited good interaction of polymers with plumbagin as evidenced by FTIR, XRD, and thermal analysis. The positive zeta potential (48.4 ± 5.57mV), optimal size (694 ± 65.76nm), low PDI (0.157), and good encapsulation efficiency (77.8 ± 3.62%) of F3 were significant. The indirect method of drug loading (58.35 ± 5.00%) confirmed the drug content of about 495.44 ± 5.00µg of plumbagin in 1mg of F3. The drug loading pattern was confirmed by TEM analysis, and the spherical morphology of the nanocomposite was confirmed by SEM analysis. F3 formulation showed 46% and 25.2% of drug release in 24h in simulated vaginal fluid at pH 4.5 and 7 respectively with sustained release and hydrolyses of lactic acid from PLA. Among all the nanoformulations evaluated, nanoformulation F3 with promising physicochemical properties showed good antifungal and antibacterial activity against various fungal and bacterial strains. F3 exhibited potent cytotoxicity with an IC50 of 3.6 ± 0.12µg/ml for HeLa and an IC50 of 0.81 ± 0.01µg/ml for SiHa cells. Altogether, the nanoformulation F3 exhibited potent antimicrobial activity against vaginal infections and cytotoxicity against cervical cancer cell lines.

RESEARCH OF THE STRESS-STRAIN STATE OF PRECAST REINFORCED CONCRETE HOLLOW CORE SLABS UNDER THE ACTION OF A CONCENTRATED AND UNIFORMLY DISTRIBUTED LOAD

The scientific work is devoted to a comprehensive study of the stress-strain state of prefabricated hollow-core floor slabs, establishing the nature of deformation, as well as determining the characteristics of crack resistance, deformability and load-bearing capacity experimentally under short-term loads. The experimental data obtained were confirmed by theoretical calculations. The scientific novelty of the experiments carried out within the framework of the presented work lies in the improvement of the principles of direct design of floor slabs from commercially produced beam slabs, the possibility of determining the stress-strain behavior of a slab structure using the formed ends. The method of monitoring the stressed behavior of a slab structure was also further developed. For the first time, the results of full-scale experimental studies of the stress-strain behavior of a prefabricated slab, carried out using the hydraulic loading method, have been obtained, and the features of the deformation of a slab embedded in the wall of a multi-story building have been experimentally established. The article provides recommendations for the practical use of the research results obtained, and also develops technical specifications for the production of concrete slabs during design and construction. The developed proposals were used in the construction of residential buildings in Kharkiv. When using the recommended grade of concrete C25/30 (instead of the actual grade C20/25 tested), the rigidity of the slab increases and its deflections will be smaller. Based on the data obtained from the experimental testing of the slabs, a generally positive test result should be stated. During further serial production of slabs, periodic testing of batches of slabs should be carried out in accordance with DSTU B V.2.6-53:2008. In this case, the slabs are accepted according to the indicators of strength, rigidity, crack resistance, fire resistance limits, frost resistance limits, as well as water resistance of slabs intended for use in aggressive environments. Keywords: concentrated load, testing, concrete, calculation, deflection, transverse force.

Development of Focused Ultrasound-Assisted Nanoplexes for RNA Delivery.

RNA-based therapeutics, including siRNA, have obtained recognition in recent years due to their potential to treat various chronic and rare diseases. However, there are still limitations to lipid-based drug delivery systems in the clinical use of RNA therapeutics due to the need for optimization in the design and the preparation process. In this study, we propose adaptive focused ultrasound (AFU) as a drug loading technique to protect RNA from degradation by encapsulating small RNA in nanoliposomes, which we term nanoplexes. The AFU method is non-invasive and isothermal, as nanoplexes are produced without direct contact with any external materials while maintaining precise temperature control according to the desired settings. The controllability of sample treatments can be effectively modulated, allowing for a wide range of ultrasound intensities to be applied. Importantly, the absence of co-solvents in the process eliminates the need for additional substances, thereby minimizing the potential for cross-contaminations. Since AFU is a non-invasive method, the entire process can be conducted under sterile conditions. A minimal volume (300 μL) is required for this process, and the treatment is speedy (10 min in this study). Our in vitro experiments with silencer CD44 siRNA, which performs as a model therapeutic drug in different mammalian cell lines, showed encouraging results (knockdown > 80%). To quantify gene silencing efficacy, we employed quantitative polymerase chain reaction (qPCR). Additionally, cryo-electron microscopy (cryo-EM) and atomic force microscopy (AFM) techniques were employed to capture images of nanoplexes. These images revealed the presence of individual nanoparticles measuring approximately 100-200 nm in contrast with the random distribution of clustered complexes observed in ultrasound-untreated samples of liposome nanoparticles and siRNA. AFU holds great potential as a standardized liposome processing and loading method because its process is fast, sterile, and does not require additional solvents.

Short-Term Electrical Load Forecasting Based on Fuzzy Rough Set Feature Selection and Multi-kernel Extreme Learning Machine

As the complexity of power systems increases, accurate load forecasting becomes crucial. This paper proposes a method for short-term electrical load forecasting that integrates fuzzy rough set (FRS) theory and multi-kernel extreme learning machine (MKELM) to improve both the accuracy and reliability of load predictions. First, we introduce the FRS theory for pre-selecting features. Next, we use correlation analysis (CA) to get rid of redundant features and choose the most important ones as prediction targets. Second, we introduce a novel prediction model based on the multi-kernel extreme learning machine (MKELM), utilizing an enhanced differential evolution algorithm (DEA) to optimize the kernel function’s parameters and the model’s weights. This approach allows for effective adaptation to various feature subsets. Experimental results on actual power load data demonstrate that our approach achieves high accuracy and reliability in short-term load forecasting. Moreover, comparative evaluations reveal that the proposed method outperforms alternative prediction models on key metrics. ANOVA and multiple comparisons further validate the statistical significance and superiority of the proposed method.

A Novel Process for Improving the Drug Loading of Highly Water-Soluble High-Dose Drug in FDM 3D Printed Tablets

ABSTRACTBackground: 3D printing technologies, also known as additive manufacturing technologies, are gaining importance in pharmaceutical research and manufacturing. These technologies are widely used in automobile, plastic, and material fabrication industries. In the recent past, pharmaceutical industries are actively working to increase the applicability of these technologies in commercial manufacturing. On the other hand, clinics and hospitals are ready to adopt these technologies due to their versatility such as flexibility, individual customization, and low-cost investment. FDM 3D printing technology is one of the widely used technologies for the manufacturing of finished products. However, this technology has limitations such as drug loading, scale-up issues, and regulatory requirements. The present study focused on developing a suitable solvent system along with a drug-loading method to increase the industrial applicability of this technology. Methods: Metformin, a high-dose, highly soluble drug, was selected as a model. Solvents such as water, ethanol, and methanol and their combinations were explored. Saturation solubility and drug loading in both PVA filaments and printed tablets were tested for drug loading. The solvent ratio of ethanol/methanol/water (8:1:1) was selected. The different infills of 10, 25, 50, 75, and 100% were printed using PVA filaments and were subjected to drug loading using soaking and solvent curing methods. Results: The soaking method has resulted in poor drug loading as well as layer separation and swelling of the polymer. The solvent curing method has a maximum drug loading of 91.9% w/w without physical deformities of the tablets. Moreover, the solvent curing method is a scalable process with less process time, and hence this method could be useful for both large-scale commercial manufacturing as well as customized formulations for personalized therapies. Conclusion: This method could be used for manufacturing thermoliable drug products and moderate-dose drug substances. Based on the research outcomes, we propose a novel, scalable, and rapid solvent-curing method for drug loading in the FDM 3D printing technique.

Combined axial load-biaxial bending interaction method for L-shaped CFSP shear walls

This paper reports the development of axial load and biaxial bending interaction method for L-shaped concrete-filled steel plate (CFSP) composite shear walls based on fiber section analysis model using the uniaxial constitutive relationship of materials. Owing to the complex interaction between the two perpendicular wall limbs (web and flange) of an L-shaped shear wall, the contour shape of the My-Mz curve is asymmetric. Linear transformation was employed to reduce the asymmetry of the contour shape, eliminate the influence of dimension, and perform parametric analysis. The analysis results indicate that when 0° ≤ θ(neutral axis angle) ≤ 90°, the influence of width-to-thickness ratio (hw1/bw) and shape coefficient (γ) on the coefficient that controls the contour shape (α) was negligible. The effect of shape coefficient (γ), steel content ratio (ρ), compressive strength of unconfined concrete (fc0), and yield strength of steel plate (fyp) on α is not significant for −180° ≤ θ ≤ −90°. Further, simplified equations were suggested to determine α. The axial load-moment interaction curve expressions for distinctive loading directions were determined by establishing the calculation method for the curve's characteristic points (axial load capacity, bending capacity, boundary points). Subsequently, the characteristic points were combined with the contour shape of the axial load-moment interaction curve derived by fitting the finite element simulation data to generate the axial load-moment interaction curve equations. A design approach was finally formulated based on the equations for the biaxial moment capacity curve and the axial load-moment interaction curves of the characteristic loading directions.

Effect of bismuth on the mechanical properties and microstructure evolution of iron matrix during drawing: a molecular dynamics study

This paper investigates the effects of bismuth nanoparticles on the mechanical properties and microstructure evolution of single-crystal iron matrix materials during the drawing process using molecular dynamics methods, and also explores the effects of different drawing speeds and loading methods on the drawing process. The results show that the incorporation of bismuth nanoparticles has a significant effect on the axial drawing force, dislocation, shear strain and crystal evolution during the drawing process. When the bismuth nanoparticles started to deform under the action of drawing force, the atomic shear strain and crystal evolution were concentrated around them, which hindered the generation of dislocations and led to the reduction of their axial drawing force. In addition, the degree of atomic shear strain and crystal evolution increases with the increase of drawing speed, leading to work hardening of the material, and thus increasing the axial drawing force. Finally, when the loading mode is positioned at the rear end, shear strain becomes more concentrated around the bismuth nanoparticles, hindering dislocation generation and increasing the material’s hardness and axial drawing force. This study is important for understanding the mechanism of bismuth nanoparticles on the iron matrix of single-crystal during the drawing process.

Carbon Nanotube Loading Strategies for Peptide Drugs: Insights from Molecular Dynamics Simulations.

Carbon nanotubes (CNTs) can be regarded as a potential platform for transmembrane drug delivery as many experimental works have demonstrated their capability to effectively transport bioactive molecules into living cells. Within this framework, the loading of a peptide drug onto either the interior or exterior of CNTs has gained considerable interest. This study aims to conduct a comprehensive comparison of these two loading methods. To this end, we performed molecular dynamics simulations and the umbrella sampling technique to investigate the interaction energy, conformational changes, and free energy changes of a model peptide drug containing α-helical structure interacting with the inner or outer walls of a 14.7-nm-long (20,20) CNT. Our finding reveals that, for a tube of such dimensions, it is thermodynamically more favorable for the peptide to be loaded onto the inner tube wall than the outer tube wall, primarily due to a larger free energy change for the former strategy. Conversely, unloading the drug from the tube interior poses greater challenges. Moreover, the tube's curvature plays an essential role in influencing the conformation of the adsorbed peptide. Despite the relatively weaker van der Waals interaction between the CNT exterior and the peptide, loading the peptide onto the exterior may induce significant conformational changes, particularly affecting the peptide's α-helix structure. In contrast, loading of the peptide on the CNT interior could maintain most of the α-helical content. CNTs do not typically attract specific peptide residues, with adsorbed groups primarily determined by the peptide's configurations and orientations. Finally, we offer a guideline for selecting an optimal loading strategy for CNT-based drug delivery.

PRIMARY AND POST-OSSEOINTEGRATION STABILITY OF SHORT (ULTRA-SHORT) IMPLANTS ON EDENTULOUS ATROPHIED DISTAL SEGMENTS OF THE MANDIBLE - AN INDICATOR OF IMMEDIATE OR DELAYED LOAD

Introduction. The issue of determining the possibility of immediate or long-term load on the selected type of implants, which will ensure the predictable result of their long-term functionality, remains an ongoing discussion. The results of the resonance frequency analysis, which perfectly characterize the stability of short and ultrashort implants at all stages of their osseointegration and post-osseointegration periods, can serve as such an indicator basis. Aim. To analyze the primary and post-osseointegration stability of short (ultra-short) implants placed by the methods at the level of the cortical bone layer and subcortically in case of bone atrophy caused by acquired final dentition defects. Materials and methods. The primary and post-osseointegration stability of thirty-nine dental short (h = 6.5 mm X b = 4.0 mm – 20 pieces) and ultra-short (h = 5.5 mm X b = 4.0 mm – 19 pieces) implants placed on the edentulous distal segments of the human mandible was studied. According to the clinical assessment that met the aim and objectives of this study, all patients were divided into four study groups: the first group consisted of patients with a preserved dentition who did not require dental implantation; the second group – 25-45 years old, the third group – 46-60 years old, and the fourth group – ≥ 61 years old. Using the resonance frequency analysis (RFA) method by Penguin Instruments, the results were interpreted in declarative units of measurement – the implant stability quotient (ISQ). Results. The installed short (ultrashort) implants, according to the methodology by the level of the cortical layer of bone tissue, are characterized by their high primary stability by anti-rotational force: in the second group of the study (25-45 years old) with a mean number (M) of 87.0 and an error of the mean (± m) of ± 2.3 ISQ; in the third group (46-60 years old) – 76.4 ± 3.0 ISQ; in the fourth group (persons ≥ 61 years old) – 69.8 ± 4.8 ISQ. Low values of primary stability were obtained in implants installed by the subcortical implantation technique in the second age group of the study and amounted to 59.6 ± 2.7 ISQ with a slight increase to 66.0 ± 4.1 ISQ in the third group and 71.7 ± 4.2 ISQ in the fourth group of the study, which do not guarantee the prognosis of functional redistribution of the supra occlusion immediate load on the biological basis, with further preservation of the course of normal physiological processes in the bone tissue around the implanted implants. Conclusions. Rehabilitation of patients with bone atrophy caused by the loss of the masticatory group of teeth is possible using short (h = 6.5-6.0 mm) and ultra-short (h = 5.5 mm) implants, with clinical justification for the choice of methods of immediate or post-osseointegration load, with a detailed resonance frequency analysis as a priority and reliable method – an effective indicator of their stability, at all stages of clinical rehabilitation of patients.

Vision-based estimation method of crowd-induced vertical dynamic loading and vibration analysis

Most existing studies concentrating on human-induced loads on structures often rely on approximate formulas based on the loading from a single gait cycle, which inherently possess certain limitations. In this paper, a novel approach utilizing a multi-person 2D posture estimation model rooted in computer vision technology to real-time identify the posture of moving human bodies on construction sites is proposed. This approach works to deduce the reaction forces of moving bodies upon the floor by analyzing the motion characteristics of different body parts during their movement, ensuring an accurate estimation of structural loading. To validate the model’s accuracy, a series of tests were conducted, leveraging force measurement equipment to scrutinize the precision of load estimation during single-person motion. This examination seeks to ascertain the potential of the load prediction model in forecasting multi-person loads within actual project environments.

Research on deep peaking cost allocation mechanism considering peaking demand subject and thermal power unit

The current peak-shaving auxiliary service cost allocation mechanism balances the revenue and expenditure of the power plant side, the peak-valley difference of the power grid is mainly caused by the peak-valley characteristics of the load and renewable energy. It is not reasonable that not reasonable the peak-shaving cost allocation mechanism does not consider user allocation. Therefore, this paper establishes a peak-shaving cost allocation mechanism that considers the peak-shaving demand subject, this article incorporates renewable energy power plants and loads into the peak-shaving demand subject. Firstly, this paper constructs an alternative scenario without peak-shaving demand through the mean line of load and available energy output and establishes an optimal scheduling model with deep peak-shaving and pumped storage power stations, this article takes the difference of system peak-shaving cost between two scenarios with and without peak-shaving demand as the marginal peak-shaving cost. Then, the Shapley value method in cooperative game is used to establish the peak-shaving cost allocation mechanism considering the main body of peak-shaving demand. In addition, It is used that the equal-kWh following load method constructed the equivalent output curve of renewable energy, following load method improves the existing allocation mechanism by comprehensive similarity. Finally, this paper analyzes and compares three different peaking cost allocation mechanisms. The example analysis shows that the peaking cost allocation mechanism considering peaking demand subjects. The example can reflect the peaking cost caused by different subjects and reduce the peaking pressure of thermal power units.

Antioxidant potential of Quartzetin and Rosemary extract as components of Nanometric apatite biopolymer materials for osteoplasty

Significant oxidative stress is induced in the bone implant surrounding tissues is a well-known problem. It's expected that the introduction of antioxidant substances (AOS) – Quercetin (Qu) and Rosemary Extract (RE) into apatite-biopolymer composites for osteoplasty as potential drug carriers will affect the antioxidant activity (AOA) and promote the natural process of the damaged bone tissues regeneration due to the active absorption of reactive oxygen species (ROS). In the present work was synthesized hydroxyapatite(HA)-Alginate(Alg) matrix, doped with micro-(ZnOMPs), nano-(ZnONPs) particles, Zn2+ ions and loaded with Qu and RE. The dependence of AOA on the method of Qu and RE loading, as well as the influence of the inorganic component (HA, ZnONPs/MPs, Zn2+) and exposure time in methanol, phosphate buffer (PBS), was analyzed. Hydrophilic RE and hydrophobic Qu are evenly distributed in the matrix volume under sonication, which can slow down their diffusion, contributing to prolonged activity. The highest AOA after 54h showed ZnONPs containing samples with Qu loaded both during synthesis (76.93 %) and saturation (93.97 %) and RE-saturated samples with ZnONPs and Zn2+ (88.53 and 75.33 %, respectively). The adsorption and retention of AOS by matrix components also take place.

Ultra-short-term prediction of microgrid source load power considering weather characteristics and multivariate correlation

Multiple microgrids interconnect to form a microgrid cluster. To fully exploit the comprehensive benefits of the microgrid cluster, it is imperative to optimize dispatch based on the matching degree between the sources and loads of each microgrid. The power of distributed energy sources such as wind and photovoltaic systems and the sensitive loads in microgrids is related to the regional weather characteristics. Given the relatively small geographical scope of microgrid areas and the fact that distributed energy sources and loads within the grid share the same weather characteristics, simultaneous ultra-short-term forecasting of power for both sources and loads is essential in the same environmental context. Firstly, the introduction of the multi-variable uniform information coefficient (MV-UIC) is proposed for extracting the correlation between weather characteristics and the sequences of source and load power. Subsequently, the application of factor analysis (FA) is introduced to reduce the dimensionality of input feature variables. Drawing inspiration from the concept of combination forecasting models, a combined forecasting model based on Error Back Propagation Training (BP), Long Short-Term Memory (LSTM), and Bidirectional Long Short-Term Memory Neural Network (BiLSTM) is constructed. This model is established on the MV-UIC-FA foundation for the joint ultra-short-term forecasting of source and load power in microgrids. Simulation is conducted using the DTU 7K 47-bus system as an example to analyze the accuracy, applicability, and effectiveness of the proposed joint forecasting method for sources and loads.

Supremacy of in-situ doping over surface loading technique for the preparation of alkali metal-promoted tellurates as efficient reusable catalysts to approach hydroxylation and dehalogenation of aryl halides

The novel alkali metal doped transition metal tellurate catalysts are prepared by two different methods, namely the in-situ doping method (alkali metal is added to the hydroxides of copper and tellurium and then calcinated) and surface loading method (alkali metal is added to the as-prepared metal tellurate and then calcined second time). In this study, the supremacy of in-situ doping over surface loading of alkali metal promoters (AM: Na, K, Rb, or Cs) to the metal tellurate for hydroxylation of aryl halides and dehalogenation of aryl halides reactions are investigated. Besides, the catalytic activity depends on the AM used for doping; the decreasing order of activity is K-Cu3TeO6 > Na-Cu3TeO6 > Rb-Cu3TeO6 > Cs-Cu3TeO6 and the occupancy of AM is in the sequence of Cs+ < Rb+ < K+ < Na+. The presence of the potassium on the copper tellurate is confirmed by XPS and flame photometry even after 6 cycles.

Advanced RBF Methods for Mapping Aerodynamic Loads onto Structures in High-Fidelity FSI Simulations

Advanced RBF Methods for Mapping Aerodynamic Loads onto Structures in High-Fidelity FSI Simulations

Research on a Calculation Method for the Horizontal Displacement of the Retaining Structure of Deep Foundation Pits

The precise calculation and effective control of the horizontal displacement of deep foundation pit retaining structures are critical for foundation pit support design and construction. Based on stress–strain linear elastomer theory and considering the deformation coordination between an enclosure wall and its internal support member, a formula for the redundant restraint force acting on the retaining wall was derived through the unit load method and the principle of elastic superposition. Moreover, a method for calculating the horizontal displacement of the retaining structure of a deep foundation pit was formulated, which is convenient for engineering applications. The method can also be used to calculate the horizontal displacement of cantilevered and anchored retaining structures when the loading conditions of the deep foundation pit and the relevant parameters of the enclosure structure are known. A case study was conducted on a standard section with an excavation width H of 19.3 m and an excavation depth h of 17.8 m. The structural parameters of the enclosure wall, along with the elastic support stiffness coefficient and soil layer parameters of the pit, were inputted into a MATLAB calculation code. Then, four internal support constraint forces Fi and the calculated values for the horizontal displacement of the enclosure wall were obtained after running the code. The calculated curve closely matched the curve of values measured in the field. The horizontal displacements of the top of the wall of several cement–soil gravity enclosure structures mentioned in the literature were also calculated. The results of these calculations were then compared with the measured data and corresponding data from the literature. The examples provided clear evidence demonstrating that the proposed method is highly reliable for calculating the horizontal displacement of deep foundation pit enclosure structures.