Surface Method Research Articles

Optimization for the Process Parameters of Nickel–Titanium Nitride Composites Fabricated via Jet Pulse Electrodeposition

The corrosion resistance of nickel–titanium nitride (Ni/TiN) composites is significantly influenced by the operation parameters during the jet pulse electrodeposition (JPE) process. The effect of current density, jet rate, TiN concentration, and duty cycle impact on the anti-corrosion property of Ni/TiN composites were investigated and optimized using the response surface method (RSM). After the optimization of the operation parameters, the corrosion current of Ni/TiN composites decreased from 9.52 × 10−5 A/cm2 to 4.63 × 10−5 A/cm2. The corrosion current of Ni/TiN composites decreased initially and then increased with an increase in current density, jet rate, TiN concentration, and duty cycle. During the jet electrodeposition process, the influence of the duty cycle on the corrosion current of Ni/TiN composites was comparatively insignificant, whereas the concentration of TiN had a significant effect on the corrosion current. The error rate between the predicted value and the measured result from the corrosion current of Ni/TiN composites was only 0.64%, indicating the high accuracy of fitting the model. Furthermore, X-ray diffraction (XRD) patterns and scanning electron microscope (SEM) images revealed that the optimized Ni/TiN composites comprised significant Ti content, fine nickel gain, and a compact, smooth structure. In addition, the electrochemical measured results demonstrated that the optimized Ni/TiN composites possessed a low self-corrosion current and high self-corrosion potential. These findings show that the optimized composites have a substantially greater corrosion resistance compared to two other unoptimized Ni/TiN composites.

Влияние горячей пластической деформации на структуру и свойства поверхностно модифицированных слоев после вневакуумной электронно-лучевой наплавки на сталь 12х18н9т с применением порошковой смеси состава 10Cr-30B

Introduction. Currently, austenitic Ni-Cr steels are widely used in the oil and gas industry for drilling wells due to its high corrosion resistance, non-magnetic properties, high impact strength, ductility and weldability. However, in order to increase the service life of products, it is necessary to increase the abrasive resistance of the surface layers while maintaining chemical resistance, which is a difficult technological task. The solution to such a problem can be the creation of sheet blanks “austenitic Ni-Cr steel - modified layer” subjected to hot plastic deformation. The purpose of the work is to study the effect of hot plastic deformation on the structure and phase composition of “modified layer – base metal” compositions obtained by the method of non-vacuum electron beam surfacing of a powder mixture of boron and chromium on austenitic Ni-Cr steel 0.12 C-18 Cr-9 Ni-Ti. Material and methods of research. The work investigated specimens made of steel 0.12 C-18 Cr-9 Ni-Ti with a modified 10Cr-30B layer formed by non-vacuum electron beam surfacing of a powder mixture of chromium and boron, and subsequent hot plastic deformation at a temperature of 950 °C. The research methods are mechanical tests for microhardness, X-ray spectral analysis of the modified layer, metallographic studies, profile analysis, calculation of lattice parameters. Results and discussion. It is revealed that after deformation, defect-free compositions are obtained, the surface layer of which is a matrix composite material containing oriented chromium carbide particles with altered crystal lattice parameters. After plastic deformation, cracks and delamination are not recorded, which allows us to speak about the high quality of the “modified layer – base metal” compositions with increased hardness values exceeding 6.5 times as-delivered steel 0.12 C-18 Cr-9 Ni-Ti (3…11 GPa and 2 GPa, respectively). In the modified layer, complex borides of type (FexCry)B are formed and located in a γ-solid solution of iron. The lattice parameter decreases for γ-iron from 3.588 Å to 3.580 Å, for boride parameter a from 5.126 Å to 5.111 Å, parameter c from 4.228 Å to 4.199 Å.

Optimal Rotor Design for Reducing Electromagnetic Vibration in Traction Motors Based on Numerical Analysis

Interior permanent magnet synchronous motor (IPMSM) for traction applications have attracted significant attention due to their advantages of high torque and power density as well as a wide operating range. However, these motors suffer from high electromagnetic vibration noise due to their complex structure and structural rigidity. The main sources of this electromagnetic vibration noise are cogging torque, torque ripple, and radial force. To predict electromagnetic vibration noise, finite element analysis (FEA) with flux density analysis of the air gap is essential. This approach allows for the calculation of radial force that is the source of the vibration and enables the prediction of vibration in advance. The data obtained from these analyses provide important guidance for reducing vibration and noise in the design of electric motors. In this paper, the cogging torque and vibration at rated and maximum operating speed are analyzed, and an optimal cogging torque and vibration reduction model, with rotor taper and two-step skew structure, is proposed using the response surface method (RSM) to minimize them. The validity of the proposed model is demonstrated through formulations and FEA based entirely on numerical analysis and results. This study is expected to contribute to the design of more efficient and quieter electric motors by providing a solution to the electromagnetic vibration noise problem generated by IPMSM for traction applications with complex structures.

Optimization of auxetic tubular structures with dragonfly-wing-shape cells through advanced multiobjective optimization techniques

Abstract Interest in auxetic structures has surged due to their unique mechanical behavior, including a negative Poisson’s ratio and exceptional energy absorption capabilities. This study aims to enhance the mechanical properties of tubular structures using a dragonfly-shaped auxetic unit cell. An optimization framework is implemented to simultaneously minimize three critical structural objectives: Poisson’s ratio, mass, and stress. Numerical simulations facilitate metamodeling via the response surface method, creating surrogate models that accurately represent each response variable. A metaheuristic optimization technique, the Non-dominated Sorting Genetic Algorithm (NSGA-II), is then employed to optimize these responses for compression performance. Experimental validation supports the numerical findings, with two optimized designs proposed. The first design (TOPSIS 1) shows reductions in Poisson’s ratio by up to 3% and stress by 45%, while the second design (TOPSIS 2) demonstrates a stress reduction of 498%. Additionally, experimental validation reveals significant improvements in energy absorption capabilities, with TOPSIS 1 and TOPSIS 2 increasing energy absorption by 58% and 545%, respectively, compared to the baseline. The integration of Industry 4.0 concepts, such as additive manufacturing and numerical simulation, proves essential in achieving efficient and effective outcomes, highlighting the importance of advanced manufacturing techniques in enhancing structural design paradigms.

Hydrodistillation Optimization for Borago officinalis L. Essential Oil and Its Chemical Composition Analysis.

The essential oil extracted from Borago officinalis L. aerial parts using hydrodistillation contains several compounds, although it yields low amounts. For the first time, this study investigated the effects of hydrodistillation parameters and optimized conditions to maximize the yield of B. officinalis essential oil while characterizing its chemical composition using gas chromatography-mass spectrometry. A single-factor evaluation of three extraction parameters-extraction time, liquid-to-solid ratio, and soaking time-revealed optimal conditions of 4h, 10:1mL/g, and 2h, respectively. Subsequently, the Box-Behnken response surface method produced a significant polynomial model, determining optimal conditions of an extraction time of 5h, a liquid-to-solid ratio of 11.06:1mL/g, and a soaking time of 2h, 17min, and 34s, resulting in an essential oil yield of 0.42%. A total of 21 compounds were identified in B. officinalis essential oil, predominantly nonacosane (29.15%) and phytol (27.92%).

Optimization of Solar-Assisted CCHP Systems: Enhancing Efficiency and Reducing Emissions Through Harris Hawks-Based Mathematical Modeling

The increasing demand for energy, driven by technological advances, population growth, and economic expansion, has intensified the focus on efficient energy management. Tri-generation systems, such as Combined Cooling, Heating, and Power (CCHP) systems, are of particular interest due to their efficiency and sustainability. Integrating renewable energy sources like solar power with traditional fossil fuels further optimizes CCHP systems. This study presents a novel method for enhancing the CCHP system efficiency by identifying the optimal design parameters and assisting decision makers in selecting the best geometric configurations. A mathematical programming model using the Harris Hawks optimizer was developed to maximize the net power and exergy efficiency while minimizing CO2 emissions in a solar-assisted CCHP system. The optimization resulted in 100 Pareto optimal solutions, offering various choices for performance improvement. This method achieved a higher net power output, satisfactory exergy efficiency, and lower CO2 emissions compared to similar studies. The study shows that the maximum net power and exergy efficiency, with reduced CO2 emissions, can be achieved with a system having a low compression ratio and low combustion chamber inlet temperature. The proposed approach surpassed the response surface method, achieving at least a 4.2% reduction in CO2 emissions and improved exergy values.

Mining, Identification, and Fermentation Optimization of Chitin Deacetylase from a Novel Strain Enterobacter sp. ZCDA27.

Chitin, a natural organic compound with content slightly lower than cellulose, is also known for chitosan, a substance derived from chitin through deacetylation. In this experiment, preliminary screening was conducted using the plate discoloration circle method, leading to the selection of a high-yield CDA-producing strain from 28 candidates through rescreening. Morphological characteristics and 16S rDNA sequence analysis revealed 99.93% homology with Enterobacter sichuanensis strain N24, thus naming this strain Enterobacter strain ZCDA27. Initial fermentation of the strain yielded CDA activity of 9.29 U/mL. Single-factor optimization was then performed, followed by a PB test to screen for significant factors affecting enzyme production. The response surface method was used to further optimize the fermentation conditions. The optimal fermentation conditions for the carbon source, nitrogen source, metal ion, fermentation temperature, time, liquid volume, and initial pH were explored. Significant factors affecting enzyme production, including MgSO4, initial medium pH, and fructose levels, were identified using the PB test. Finally, the fermentation conditions of ZCDA27 were optimized using the Box-Behnken design combined with RSM, which comprised fructose at 1.020%, magnesium sulfate at 0.016%, and peptone at 1%. The fermentation conditions included a temperature of 37, initial pH of 7.1, rotation speed of 140 × g, fermentation time of 28h, inoculation amount of 2%, and liquid volume of 40%. Under these conditions, the enzyme activity of ZCDA27 reached 14.52 U/mL, a 1.6-fold increase from the pre-optimization levels. In summary, this study provides an experimental foundation for further development and application of Enterobacter spp. ZCDA27 CDA.

3D geological fine modeling and dynamic updating method of fault slope in open-pit coal mine

Combining the requirements for refined modeling and dynamic update of fault slope geological models in open-pit coal mines, we systematically elaborated on the elements and rules of slope 3D geological modeling and proposed a fine modeling and dynamic updating method based on digital elevation model (DEM) and half-edge boundary representation (B-Rep) data structures. Initially, the stratigraphic division of the study area is conducted based on borehole and section data, combined with the geological evolution history and the level set theory. Applying inverse distance weighting (IDW) for estimation, the geological interface triangular irregular network (TIN) is constructed using the TIN algorithm. Secondly, fine reconstruction of fault surfaces through Morphing transformation improves the accuracy and smoothness of fault surface shape reconstruction under sparse data conditions. Then, the intersection-cutting processing method of fault-fault and fault-stratum for slope geological ground state model modeling under complex fault segmentation is investigated. Finally, constructing 3D geological models of fault slopes and the integrated correction of surface and subsurface are realized through dynamic updating methods for 3D surfaces and strata. Taking the 3D geological modeling of a fault slope of an open-pit coal mine in China as an example, the feasibility of the technical method is verified.

Geometric Optimization of the Five-Point Double-Toggle System for the Clamping Unit of an Injection Molding Machine with the Response Surface Method

Injection molding is one of the most used processes for the manufacture of plastic products with high-volume capacity. The five-point double toggle mechanism is frequently employed in the clamping unit to augment the force generated by a linear actuator, thereby achieving the requisite clamping force. This is a crucial aspect that determines the productivity and quality of the finished product in the injection molding process. Nevertheless, the geometrical synthesis of this type of mechanism has not been sufficiently addressed with regard to its integration into the mold design and the opening/closing stroke. This paper presents a novel approach for analyzing and evaluating the impact of parameters pertaining to mechanism posture on its force amplification, employing the Taguchi method. The relationship between force amplification ratio and the most influential parameters is simplified with the Face-Centered Central Composite Design (FCCCD) method, thereby allowing the optimal posture of the mechanism at the mold-closing stage to be determined. With these optimal parameters, once the mold height and desired opening/closing stroke have been selected, the dimensions of the links in the mechanism can be calculated. The results demonstrate that there are numerous combinations of these parameters that can yield a high force amplification ratio, thus providing the designer with a range of options for the design of a clamping unit. The proposed method can be employed at the initial stage of the design process to obtain a preliminary design, thus preparing for the dynamic analysis or further optimization problems of the mechanism.

Preparation, oil removal and flocculation efficiency evaluation of a PAC-P(AM-BA) hybrid polymer flocculant based on response surface method

In this study, a novel inorganic-organic hybrid polymer flocculant PAC-P(AM-BA) with hydrophobic groups was synthesized using the aqueous solution free radical micelle polymerization method. The raw materials used were polyaluminum chloride (PAC), polyacrylamide (AM), and butadiene acetate (BA). Experimental results demonstrated that the optimal preparation conditions for PAC-P(AM-BA) were as follows: initiator mass fraction of 0.15% (based on total monomer), n(AM):n(BA)=98:2, urea mass fraction of 3.00%, total monomer mass fraction of 15.597%, inorganic component (PAC) mass fraction of 1.346%, and polymerization temperature of 24.225℃. In PAC-P(AM-BA), BA was chemically bonded within PAM, while PAC was connected to the organic long chain through ion bonding. Moreover, the thermal decomposition temperature of PAC-P(AM-BA) was found to be 275.93℃. The hybrid flocculant exhibited a rough surface and displayed strong adsorption bridge formation as well as net capture and sweeping performance.

Sulfonic-acid-functionalized lignin-derived LC900@SO3H: A promising catalyst for the efficient production of biodiesel via the esterification of oleic acid

The renewable and clean biodiesel production makes higher demands for cheap, green and efficient catalysts. A sulfonic-acid-functionalized LC900@SO3H catalyst was prepared using alkali lignin as the carbon source, which was applied in the esterification of oleic acid to produce biodiesel. The yield of biodiesel reached 96.3% under mild conditions (Temperature = 95 ◦C, Catalyst dosage = 3.5wt%, MeOH/Oleic acid = 11.2:1, Time = 1.5h). The catalysts were reused at least 3 times with a high biodiesel yield of over 80%. The morphological and spectral analyses of the catalysts were conducted using BET, TGA, Raman, SEM, FTIR, and XPS, and the products were analyzed by GC and GC-MS. Characterizations indicated that the huge specific surface area (1618.68 m2/g) and large pore volume (0.8573 cm3/g) endow the LC900@SO3H with abundant sulfonic-acid-functionalized active sites for excellent catalytic activity. In addition, the response surface method (RSM) revealed the interaction of different reaction conditions for biodiesel production. The cost of 1kg catalyst was estimated as $3.59, showing good economic viabilities.

The performance analysis of a compressed air energy storage (CAES) for peak moving with cooling, Heating, and power production

This study focuses on modeling and optimizing a multifaceted geothermal-based energy production system within the context of Denmark. The primary objectives revolve around enhancing system efficiency and reducing operational costs. The system under investigation comprises geothermal components, an organic Rankine cycle, a compressed air energy storage facility, and an absorption chiller. The organic Rankine cycle operates using refrigerants R123 and ammonia, effectively converting thermal energy into electricity and thermal energy for various applications. Optimization was carried out employing the Response Surface Method in tandem with Design-Expert software, facilitating the fine-tuning of objective functions. Two key objectives were selected: Exergy Round Trip Efficiency and cost rate, aimed at improving technical performance and curbing economic expenditure. A range of design variables were considered for optimization, including turbine and pump inlet temperatures, geothermal mass flow rate, turbine and pump efficiencies, compressor and gas turbine efficiency, inlet pressure to the compressed air energy storage tank, and evaporator pinch point temperature. The system reached an impressive exergy efficiency peak of 77.98%, accompanied by a modest cost rate of 5.48 $/h. The costliest components in the system were the compressed air energy storage unit, followed closely by organic Rankine cycle 1 and organic Rankine cycle 2. In contemplating the practical implementation of this innovative energy system, ten cities in Denmark underwent rigorous analysis, accounting for technical and economic factors. Subsequent assessments identified Aarhus as the optimal location to initiate the system. The environmental results showed that by producing 13981.9 megawatts of electricity annually in Arhus City, it is possible to help reduce CO2 emissions by 2853.2 tons of CO2/year and avoid environmental costs of 68455.3 $/year. The environmental assessment also highlighted the potential for substantial green space expansion, estimating an additional 13 hectares of green areas in the city of Aarhus, Denmark.

Optimizing corncob pretreatment with eco-friendly deep eutectic solvents to enhance lignin extraction and cellulose-to-glucose conversion

Deep eutectic solvents (DES) are an eco-friendly, cost-effective alternative to traditional ionic liquids for biomass pretreatment, with unique characteristics encompassed by hydrogen bond donor (HBD), the molar ratio of hydrogen bond acceptor (HBA) to HBD, temperature, and time affecting efficiency. Despite its potential, a comprehensive study exploring the interplay of these factors is limited. This study explores the optimization of pretreatment variables using choline chloride/lactic acid (1:5) via the response surface method (RSM). It aims to evaluate the effects of time and temperature on lignin extraction, cellulose-to-glucose conversion, and hemicellulose removal. Employing a 22 central composite design with temperature (80–140 °C) and time (2–6 h) as variables, optimal conditions were 123 °C for 6 h. Results include 90.08±1.42 % lignin extraction, 68.77±6.9 % cellulose-to-glucose conversion, and 77.34±0.85 % hemicellulose removal, with 52.52±8.07 % lignin recovery. The fractions of pretreated CC and lignin recovered in the optimal condition found were characterized by X-ray diffraction (XDR), Fourier transform infrared spectroscopy (FTIR), 1H, 13C, 2D-HSQC NMR spectroscopy, Thermogravimetric analysis (TGA/DTG), Gel Permeation Chromatography (GPC) to elucidate chemical characteristics of the materials obtained and facilitate downstream valorization. High efficiency was achieved in lignin extraction and cellulose conversion, and addressing solvent viscosity and DES recycling will further enhance the potential for industrial scalability.

Enhancing Paddy Rice Drying Quality with Non-Destructive LPG Refrigeration System in a Fixed-Bed Dryer

High relative air humidity in humid climates slows the process of paddy drying and leads to rehydration. The use of a liquefied petroleum gas (LPG) refrigeration system for dehumidifying ambient air effectively reduces drying time and improves product quality in a non-destructive manner. This environmentally friendly method enhances both the quality of the rice samples and the efficiency of the drying process. This study examined the impact of dehumidification on Hashemi rice quality and moisture reduction, using the Response Surface Method to optimize drying conditions at three levels of temperature (40, 45, and 50 °C), air velocity (1.7, 2.2, and 2.7 m/s), and relative humidity (70, 80, and 90%). The results showed that dehumidification led to a moisture content of 6% and the lowest cracking rate of 2%. Temperature was the most influential factor, affecting responses by 73.09% under dehumidified conditions. Optimal conditions of 40 °C, 80% RH, and 1.7 m/s air velocity resulted in a cracking rate of 2% and a desirability index of 0.958. The Response Surface Method showed an excellent fit for the cracking index (R² = 0.98). These results highlight the LPG refrigeration system as an effective, non-destructive, and environmentally friendly method for drying paddy in humid regions, making it suitable for industrial applications.

Colistin-niclosamide effervescent dry suspension combats colistin-resistant Salmonella in vitro and in vivo

The increasing incidence of bacterial infections caused by multidrug-resistant (MDR) Gram-negative bacteria has deepened the need for new effective treatments. It has been reported that niclosamide (NIC) can restore the sensitivity of Gram-negative bacteria to colistin (COL). However, NIC is practically insoluble in water and sparingly soluble in organic solvents, leading to limited therapeutic applications. This study aims to prepare a COL-NIC effervescent dry suspension (CNEDS) and evaluate its antibacterial effect against COL-resistant Salmonella both in vitro and in broiler chickens. With the sedimentation volume ratio as an index, suitable suspending agent, wetting agent, filler and effervescent agent were screened through a single-factor method. The preparation conditions were optimized using the Box-Behnken response surface method to obtain the formulation for CNEDS. The quality evaluation results showed that the successfully prepared CNEDS had a sedimentation volume ratio of 0.99, a drying weight loss of 1.3%, and a re-dispersion capability of 1-2 times, all of which met pharmacopoeial requirements. In terms of pharmacological evaluation, we first demonstrated that CNEDS substantially restored COL sensitivity against COL-resistant bacteria. Subsequently, time-killing analysis, scanning electron microscopy (SEM) and live/dead assays confirmed the antibacterial activity of CNEDS against COL-resistant bacteria. Finally, a Salmonella infection model in broiler chickens was established to further assess the therapeutic effect of CNEDS in vivo. CNEDS improved the survival rate of broiler chickens, reduced the bacterial burden on organs. These findings suggest that CNEDS effectively overcome COL resistance, indicating its potential for the treatment of COL-resistant bacterial infections in broiler chickens.

CFD-based optimization of a high-throughput recycle micromixer

The present paper uses computational fluid dynamics (CFD) and the response surface method (RSM) to optimize the performance of a novel high-throughput recycle micromixer. The micromixing of DI water and blood plasma with various thermophysical properties is simulated for a broad range of DI water Reynolds numbers (50 <ReDI< 400). The impacts of geometrical parameters and ReDI are assessed on the mixing index (MI) and pressure drop (Δp). It is found that the chaotic advection can be enhanced by changing effective parameters due to the recirculating flow in feedback channels and vortex generation in mixing chambers. Accordingly, the channel depth has a major effect on MI and Δp in such a way that when the channel depth changes from 50 to 1000 μm, MI is augmented from 23 % to 73.25 % and Δp is reduced from 75.171 kPa to 12.85 kPa when ReDI= 400. It is revealed that MI is an enhancing function of ReDIand the number of mixing units. Besides, the figure-of-merit (FoM) analysis shows that the proposed micromixer gives a much greater FoM compared to the micromixers with ordered flow patterns when Re is an order of 50. The RSM provides two mathematical correlations for MI and Δp to obtain an optimal recycle micromixer that can be efficiently utilized in biological and clinical applications.

Analysis of Volume Calculations for Clay Mining Excavation Plans Using The Surface to Surface Method

Abstract Calculating the volume of excavation is generally a large and complex problem for a project in an industry. This is because the accuracy of the volume calculation affects the project budget for the project provider. Calculating the excavation volume is important aspect of mine planning since it serves as a guide for hitting production goals in terms of both profit and technical success. The method commonly used in calculating excavation volume is surface to surface. To overcome this problem, a method or technique is needed to calculate the excavation volume that can provide accurate calculation results. the surface-to-surface approach will be used to optimize volume calculations. Additionally, the accuracy of excavation volume calculations based on ASTM (American Society for Testing and Material) tolerances. Analysis is carried out by calculating the smallest percentage value. In this way, excavation volume results will be obtained that are close to the reference value based on ASTM tolerances. The aim of this research is to determine the optimal results of surface-to-surface method volume calculations from the most accurate contour intervals. The volume calculation results that are closest to the reference of 999,922.91 tonnes have a percentage value of 0.01% with a volume difference to the forecast study of 77.09 tonnes. To obtain accurate volume calculations, a contour interval of 1 meter is better than several other contour intervals. This research can become new alternative in volume calculations to support SDGs activities, especially in the resource use efficiency to achieve a sustainable industrialisation.

Optimizing Duct Geometry for Micro-Scale VAWTs: Exploring Aerodynamics and Aeroacoustics with URANS and DDES Models

Among several advantages of the Vertical Axis Wind Turbines (VAWTs), such as the low cut-in speed, these turbines have lower efficiency compared to Horizontal Axis Wind Turbines (HAWTs). In order to increase the power of VAWTs, a novel approach is employed to address the aforementioned issue. In this study, a convergent-divergent duct (including three components: nozzle, diffuser, and flange) is used, and in the first step of this study, the angles and lengths of all duct components and throat width are optimized (in 3D configuration). In the optimization process, first, the design points are determined by the Design of Experiment (DOE) method, and for each design point, the flow field inside the duct is modeled by the Reynolds-Averaged Navier-Stokes (RANS) approach. Moreover, the objective function of this optimization problem is to maximize the velocity of the flow inside the duct. In the following, the general treatment of the statistical population is forecasted using the Response Surface Method (RSM), and the optimal duct is obtained using the Genetic Algorithm (GA). It is observed that the optimal duct increases the local wind speed up to 1.99 times (from 5 m/s to 9.94 m/s at the throat). Furthermore, a sensitivity analysis was performed on the duct components, which are the most effective parameters in increasing wind speed, nozzle angle, and nozzle length. In the second step, a Darrieus VAWT (with both 2D and 3D configurations) is numerically validated, and then this turbine is scaled-down and located in the optimal duct. The position and tip-clearance of a turbine within the optimal duct are investigated to find the best configuration for higher power generation. Subsequently, both the bare wind turbine and the ducted wind turbine undergo thorough aerodynamic and aeroacoustic analysis, using unsteady RANS and Delayed Detached Eddy Simulations (DDES) approaches, respectively. The results reveal a remarkable improvement in the aerodynamic efficiency (power coefficient increased up to 2.5 times) with the addition of the optimal duct, while the aeroacoustic performance of the system is compromised, leading to an increase in sound pressure level.

Optimisation of hexagon-shaped floating units using the response surface method

ABSTRACT A hexagon-shaped floating unit (HS-FU) was proposed, and the optimisation was performed with respect to the geometric dimension based on the response surface method (RSM). A multi-objective optimisation model considering the weight and heave response was established to achieve a satisfactory balance between economy and safety, constrained by the roll, initial metacentric height, freeboard, and collision issue. The results show that, opposite to the heave response, the structural weight is positively proportional to the side lengths of the water tank and living area; the stability can be improved by increasing the water tank height and the living area side length. The combination of weighting factors with a value of 0.4 for weight and 0.6 for heave was selected as one of the optimal designs. Compared with the initial design, the optimal design shows better performance, with the heave response decreasing by 22.51% and the initial metacentric height increasing by 28.30%.

Modal Matching of Key Components in the Launching System Based on Response Surface Method

This chapter adopts Response Surface Methodology (RSM) combined with dynamic simulation and statistical analysis to deeply investigate the impact of modal matching of the inherent frequencies of key components of the launching system on the disturbances at the launch box opening during firing. Through experimental design, a polynomial fitting response surface model is established between design parameters and response objectives. The ultimate goal is to find the optimal design scheme that minimizes the initial disturbance, thereby achieving effective modal matching between the main components of the launching device. This research aims to provide a theoretical basis for improving firing accuracy and system stability.