To see the other types of publications on this topic, follow the link: Response Spectrum Method(RSM).
Journal articles on the topic 'Response Spectrum Method(RSM)'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Response Spectrum Method(RSM).'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
S.S. Mane and Ashwini B. Sankpal. "A Comparative Review of Dynamic Analysis Techniques for Elevated Water Tanks: Time History Method Versus Response Spectrum Method." International Research Journal on Advanced Engineering and Management (IRJAEM) 2, no. 12 (2024): 3624–32. https://doi.org/10.47392/irjaem.2024.0537.
Full textAbstract:
This paper presents a comprehensive review of dynamic analysis techniques for elevated water tanks, with a specific focus on comparing the Time History Method (THM) and Response Spectrum Method (RSM). Drawing upon a wide range of literature sources, the review synthesizes existing research efforts dedicated to understanding structural behavior, seismic performance, bracing configurations, material considerations, and soil-structure interaction in the context of elevated water tanks. Despite the extensive body of literature in this field, a notable research gap exists in the systematic comparison of dynamic analysis techniques, particularly between THM and RSM. This paper highlights the need for a comparative review to evaluate the advantages, limitations, and applicability of THM and RSM for dynamic analysis of elevated water tanks, providing valuable guidance for engineers and researchers in selecting the most suitable method based on project requirements and constraints.
2
Mohammad, Hussain, and Amaresh S. Patil Prof. "Design & Plan of Skyscraper by ETABS & BIM Tool Software." JOURNAL OF SCIENTIFIC RESEARCH AND TECHNOLOGY 1, no. 1 (2023): 68–87. https://doi.org/10.5281/zenodo.7869114.
Full textAbstract:
<strong>Today, skyscrapers and other large buildings are common in India's main cities. This study applies a BIM method to skyscraper construction technology. AutoCAD is used for skyscraper planning, and Revit is used for modelling. A comparison is made between advanced structural analysis tools like ETABS and BIM (AutoCAD, Revit). In the proposed study, ETABS created and evaluated a skyscraper model in accordance with IS-875-Part1-3 and IS1893-2016-Part1. Today, skyscrapers and other large buildings are common in India's main cities. This study applies a BIM method to skyscraper construction technology. AutoCAD is used for skyscraper planning, and Revit is used for modelling. A comparison is made between advanced structural analysis tools like ETABS and BIM (AutoCAD, Revit). In the proposed study, ETABS created and evaluated a skyscraper model in accordance with IS-875-Part1-3 and IS1893-2016-Part1. The behavior of 40 storey building which lies in seismic zone Ⅱ has been studied.The Dynamic effects is find by Response spectrum method.One of the parameters such as base shear obtained by Equivalent static method and Response spectrum method has compared.All the parameters like Story dispⅼacement, Story drift, Base shear, Overturning moments, Acceⅼeration & Time period are calculated After results we concluded that BⅠM makes the entire building process simpler and more efficient.The conclusion is documented in the literature i.e.,the stórey òverturning mòment is inversely proportionaⅼ with storey height.And Base shear for Equivaⅼent Static Method(ESM) compared with Response Spectrum Method (RSM), to ensured that minimum strength of designed structure using RSM is similar to strength of designed structure using ESM,so scaling have to done.All other parameters are to be found to under maximum permissible limit.</strong>
3
M, Roopa, Venugopal H, Jayachandra, and Nagaral Madeva. "Soil Structure Interaction Analysis of a Single Layer Latticed Geodesic Dome." Indian Journal of Science and Technology 15, no. 7 (2022): 292–99. https://doi.org/10.17485/IJST/v15i7.35.
Full textAbstract:
Abstract <strong>Objectives:</strong> To analyze the soil structure interaction (SSI) behaviour of a geodesic dome for in situ soil conditions by using the response spectrum method (RSM). <strong>Methods:</strong> An existing geodesic dome of diameter 31m and a total height of 23.6 m is modeled using SAP2000, and the model is evaluated for the soil structure interaction. The existing geodesic dome structure falls under seismic zone II according to IS: 1893-2016, so the in-situ soil properties of the structure are considered to design the soil springs. <strong>Findings:</strong> Base shear in SSI condition observed 3.72 % lesser compared to the nonSSI conditions and natural time period, has been increased to 60.8% compared to nonSSI as it affirms the flexibility of the geodesic dome. <strong>Novelty:</strong> The present study aims to evaluate the dynamic behavior of the geodesic dome, which is a nonconventional structure in design and shape. Few investigations were carried out to analyze the soil structure interaction behavior on such structures. <strong>Keywords:</strong> Soil structure Interaction; geodesic dome; response spectrum method; SAP2000; dynamic behaviour
4
Abduh, Gierrald, Muhammad Said, and Poedji Loekitowati Hariani. "Photocatalytic Degradation of Congo Red Dye using ZnFe2O4/SnO2 Composite with Response Surface Methodology (RSM) Optimization." Trends in Sciences 22, no. 7 (2025): 9988. https://doi.org/10.48048/tis.2025.9988.
Full textAbstract:
In this investigation, the synthesized ZnFe2O4/SnO2 composites for the photocatalytic degradation of Congo red dye. Doping SnO₂ onto ZnFe2O4 optimized the energy gap, promoting light absorption in the visible spectrum. The ZnFe2O4/SnO2 composites were analyzed using XRD, UV-DRS, SEM-EDS, VSM, and pHpzc. Photocatalytic degradation is optimized using Central Composite Design (CCD), which is based on response surface methodology (RSM). The XRD characterization results of the ZnFe2O4/SnO2 composites demonstrate the success of the synthesis method. The composite has a combined 2θ of ZnFe2O4 and SnO2, with a crystallite size of 17.50 nm. A band gap value of 2.46 eV indicates that the material can absorb most of the visible light spectrum. The EDS mapping results verify the presence of SnO2 on the surface of ZnFe2O4, and the saturation magnetization value of 12.80 emu/g confirmed the composite’s magnetic properties. Degradation optimization using RSM indicated that the quadratic model effectively characterizes the photocatalytic degradation of Congo red dye. The RSM model’s high accuracy in predicting experimental outcomes is evidenced by the minor difference in efficiency degradation between experimental and predicted values, with an R2 of 0.9851 and a p-value < 0.05. The optimum degradation efficiency was achieved at a solution pH of 4, a Congo red dye concentration of 10 mg/L, and an irradiation time of 80 min. The composite exhibits great stability, efficiency, and reliability; the reuse evaluation after 5 cycles indicated a deterioration reduction of less than 5 %. HIGHLIGHTS Doping SnO₂ into ZnFe₂O₄ reduces the band gap energy, thereby enhancing its absorption capability within the visible light spectrum. Degradation optimization using RSM indicated that the quadratic model where solution pH, dye concentration and irradiation time affect degradation efficiency. The ZnFe₂O₄/SnO₂ composite demonstrated the ability to degrade over 90% of Congo red dye The deterioration efficiency diminished by less than 5% after after five consecutive cycles, signifying exceptional material stability. GRAPHICAL ABSTRACT
5
RODRIGUES, R. A., C. E. N. MAZZILLI, and T. N. BITTENCOURT. "Comparative analysis of normative provisions for seismic design and detailing of reinforced concrete structures." Revista IBRACON de Estruturas e Materiais 12, no. 5 (2019): 1220–47. http://dx.doi.org/10.1590/s1983-41952019000500013.
Full textAbstract:
Abstract The main objective of this work is to carry out a comparative analysis between the methods and provisions of the Brazilian code ABNT NBR 15421:2006 and those of the ASCE/SEI 7 and the Eurocode 8, on the seismic design of structures. The similarities and differences between these standards, as far as the application of the Equivalent Lateral Forces method (ELFM) and the Response Spectrum method (RSM) are concerned, will be addressed. The responses will be evaluated for a case study that will be modelled by the SCIA Engineer 17 software. This paper also presents some comments on the detailing of reinforced concrete structures to ensure a good performance under seismic loading, allowing for a more favourable interpretation of the seismic analysis results.
6
Wang, Jinghui, Ping Tan, Tiancan Huang, Xuefeng He, and Fulin Zhou. "Shear Fragility Analysis of Non-Classically Damped Three-Dimensional Structures Under Seismic Excitation." Buildings 14, no. 12 (2024): 3967. https://doi.org/10.3390/buildings14123967.
Full textAbstract:
This study proposes a seismic performance evaluation method for structures using the base shear index to calculate the collapse probability. After non-proportional damping was applied to the three-dimensional bar system model, the structural dynamic response was computed through large-scale finite element analysis. A three-dimensional matrix element for calculating viscous dampers was established in this study. The viscous unified elastoplastic (VUEL) damper element program was compiled using the Fortran language into the ABAQUS 6.14 software. An incremental dynamic analysis (IDA) routine was developed using Python 3.0 within the environment of ABAQUS. The uncontrolled structure was designed using the forced decoupling response spectrum method (FD-RSM), while the damped structure was designed using the complex modal response spectrum method (CM-RSM). Seismic fragility analysis was conducted on both uncontrolled and damped structures using the recommended far-field and near-field earthquake records from ATC-63 FEMAP-695. The shear-based fragility index and collapse probability were investigated to comprehensively assess the seismic performance of the uncontrolled and damped structures. The analysis results indicated that the ratios of the limit performance states for moderate damage (IO), severe damage (LS), and complete damage (CP) in the structure were 1:1.6:2.6. Compared with the various limit performance states of the uncontrolled structures, the increments in the moderate, severe, and complete damage limit performance states of the damped structures were 12.79%, 14.86%, and 16.97%, respectively.
7
QUAYYUM, SHAHRIAR, ISLAM MOHAMMAD NAZMUL, MOST MAHBUBA IASMIN, and KHAN MAHMUD AMANAT. "EFFECTS OF RANDOMLY DISTRIBUTED INFILL ON COLUMNS OF REINFORCED CONCRETE FRAMES WITH SOFT GROUND STOREY." International Journal of Structural Stability and Dynamics 10, no. 03 (2010): 555–69. http://dx.doi.org/10.1142/s0219455410003610.
Full textAbstract:
Reinforced concrete (RC) frames with an open ground floor and various infill distributions have been analyzed for seismic loadings by the finite element method. The infills have been modeled by diagonal struts. Focus is placed on the effects of infill distribution on various structural responses, including (i) the lateral deflection, (ii) the column axial forces, (iii) the column bending moments, (iv) the base shear, and (v) the natural period of the frame. The equivalent static force method (ESFM) and response spectrum method (RSM) for linear structures have been applied, and the results obtained have been compared. It was found that the structural responses do not change appreciably by the ESFM analysis for random infill distributions, while they increase noticeably in the RSM analysis. This manifests the inadequacy of using the ESFM for general purposes, for which modifications were proposed in this paper for the design of RC columns. As the natural period of the RC frame converges with the code equations only for higher amounts of infill, it is necessary to incorporate the amount and distribution of infill in the dynamic analysis of RC frames.
8
Trawczyńska, Ilona, and Sylwia Kwiatkowska-Marks. "Application of Response Surface Methodology for Optimization of the Biosorption Process from Copper-Containing Wastewater." Molecules 28, no. 1 (2023): 444. http://dx.doi.org/10.3390/molecules28010444.
Full textAbstract:
Copper-containing wastewater is a significant problem in the water industry. In this work, biosorption of copper ions on alginate beads have been considered as a promising solution. The effective diffusion coefficient De is the parameter describing the diffusion of copper ions in calcium alginate granules. Granules with a wide spectrum of alginate content from several to several dozen percent (0.6–20%) were tested. The granules with an alginate content of 20% were produced by a new method. The conductometric method was used to determine De. The study determined the De values depending on the process parameters (temperature and pH of copper solutions) and the alginate content in the granules. The RSM method was used to analyze the obtained results. The conducted research proved that all analyzed factors significantly affect the value of the diffusion coefficient (R2 = 0.98). The optimum operating conditions for biosorption of copper ions from CuCl2 salt, on alginate beads obtained by RSM were as follows: 0.57% of alginate content in the granules, temperature of 60.2 °C, and pH of 2. The maximum value of De was found to be 2.42·10−9 m2/s.
9
Srikandace, Yoice, Kamarisima Kamarisima, Sastia Prama Putri, and Pingkan Adiatiawati. "Optimization of Medium Components for Enhancing Antibacterial Activity of Marine Streptomyces aureofaciens A3 through Response Surface Methodology." Trends in Sciences 22, no. 3 (2025): 9144. https://doi.org/10.48048/tis.2025.9144.
Full textAbstract:
This study is the first to report on the statistical optimization of an antibacterial production medium for the marine bacterium Streptomyces aureofaciens A3. Glycolic and furoic acids have not been previously documented as metabolites produced by Streptomyces, especially by S. aureofaciens A3. The antibacterial metabolites were generated in an ISP4 medium enriched with artificial seawater with different concentrations of starch, NaCl, and ammonium sulfate. Media components were optimized through the Response Surface Method (RSM) using the Box-Behnken design (BBD) in submerged fermentation. Antibacterial metabolites produced during fermentation were extracted with ethyl acetate (EA) to obtain EA extracts. The extract activities were tested using the Kirby-Bauer method, and the extract compounds were annotated using GC/MS. The results showed that the specific concentrations of starch, ammonium sulfate, and NaCl enhanced the antibacterial activity for each tested bacteria were 11.06 - 12.07 g/L for starch and 1.39 - 1.56 g/L for ammonium sulfate and 1.76 - 2.45 g/L for NaCl. The media increased higher antibacterial activity against pathogens with rising percentages of inhibition zones of E. coli (62.33 %), S. aureus (9.41 %), S. typhimurium (48.69 %), P. aeruginosa (39.16 %) and B. subtilis (8.58 %), respectively. The inhibition zones of each test bacteria were 10.88 - 17.97 mm and categorized as strong antibacterial activity. GC/MS derivatization results showed that the annotated compounds in EA extracts consisted of primary metabolites such as glycolic acid, palmitic acid, stearic acid, lauric acid, myristic acid, oleic acid and secondary metabolites were furoic acid, phthalate acid, benzoic acid, methylmalonic acid. This study showed that the RSM method is efficient and effective for improving the activity of broad-spectrum antibacterial agents produced by S. aureofaciens A3. The application of RSM to optimize ISP4 medium enables the large-scale production of antibacterial metabolites for the pharmaceutical industry. HIGHLIGHTS The antibacterial activity of marine Streptomyces aureofaciens A3 was first optimized using the Response Surface Method with ISP4-modified media. Broad-spectrum antibacterial activity increases against all pathogenic bacteria with a media composition similar to seawater. The low ammonium sulfate concentration induces higher antibacterial activity against bacterial pathogens. GRAPHICAL ABSTRACT
10
Song, Jie, Zhi Gang Song, and Yi Jie Shen. "Analysis of RMS Acceleration Response Spectrum for Random Pedestrian Loads." Advanced Materials Research 261-263 (May 2011): 292–98. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.292.
Full textAbstract:
Pedestrian loads are affected by such uncertain parameters as walking step frequency, step length, dynamic load factors and phases of harmonic components, which lead to the uncertainties of structural response. A new method for calculation random response spectrum based on uniform design is introduced to reduce calculation work. A few representative samples of loads time histories are simulated using uniform design, and then the RMS acceleration response spectrums are obtained by dynamic time-history analysis of beam structures with different spans and damping ratios. The RMS acceleration response spectrums which have certain percentiles are obtained by reliability analysis based on response surface. Ultimately the general forms of RMS acceleration response spectrums are deduced from the analyses of sensitivities for damping ratio and span.
11
Machado, M. R., and J. M. C. Dos Santos. "Reliability Analysis of Damaged Beam Spectral Element with Parameter Uncertainties." Shock and Vibration 2015 (2015): 1–12. http://dx.doi.org/10.1155/2015/574846.
Full textAbstract:
The paper examines the influence of uncertainty parameters on the wave propagation responses at high frequencies for a damaged beam structure in the structural reliability context. The reliability analyses were performed using the perturbation method, First-Order Reliability Method (FORM), and response surface method (RSM) which were compared with Monte Carlo simulation (MCS) under the spectral element method environment. The simulated results were performed to investigate the effects of material property and geometric uncertainties on the response at high frequency modes, such as the computational efficiency of reliability methods. For the first time, the spectral element method is used in the context of reliability analysis at medium and high frequency bands applied to damage detection. It has shown the effects of parameters uncertainty on the dynamic beam response due on an impulsive load and the robustness of each method. Numerical examples in a bending vibrating beam with random parameters are performed to verify the computational efficiency of the present study.
12
Kitahara, Masaru, and Takeshi Ishihara. "Seismic soil–structure interaction analysis of wind turbine support structures using augmented complex mode superposition response spectrum method." Wind Energy Science 7, no. 3 (2022): 1007–20. http://dx.doi.org/10.5194/wes-7-1007-2022.
Full textAbstract:
Abstract. In this study, the seismic soil–structure interaction (SSI) of wind turbine support structures is investigated based on the complex mode superposition approach. For accurate and efficient estimation of seismic loadings on wind turbine support structures, an augmented complex mode superposition response spectrum method (RSM) is developed, where the maximum shear force and bending moment of the non-classically damped system are analytically derived. An empirical formula of the modal damping ratios with a threshold value for the allowable damping ratio is also proposed to improve the prediction accuracy of the shear force acting on the footing. Furthermore, additional loadings to consider the contribution of the mass moment of inertia of rotor and nacelle assembly and P−Δ effect to the bending moment on the tower are analytically derived. The proposed formulae are first demonstrated upon a 2 MW wind turbine supported by two different types of foundations. A parametric study is then carried out by changing the tower geometries and soil conditions to propose the threshold value for the allowable damping ratio.
13
Nan, Yu, Zhi Gang Song, and Shi Jiao. "Response Spectrum Analysis Method of Footbridge Lateral Vibration under Man-Bridge Interaction." Advanced Materials Research 838-841 (November 2013): 1165–69. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.1165.
Full textAbstract:
Based on the uniform experimental design method and combining with the additional lateral pedestrian role derived from social force, this paper establishes human-bridge dynamic interaction model and calculates dynamic response of simply supported structures with different span, damping ratio, walking stride frequency and other parameters under the man-bridge dynamic interaction. The acceleration response spectrum is obtained by FFT transform of acceleration response. Then RMS-acceleration response spectrum is calculated in accordance with ISO overall frequency weighting method and the response spectrum envelope formula is fitted by parametric analysis.
14
Wen, Yadong, Weijun Wang, Hua Liu, et al. "A Shape Optimization Method of a Specified Point Absorber Wave Energy Converter for the South China Sea." Energies 11, no. 10 (2018): 2645. http://dx.doi.org/10.3390/en11102645.
Full textAbstract:
In this paper, a shape optimization method of a truncated conical point absorber wave energy converter is proposed. This method converts the wave energy absorption efficiency into the matching problem between the wave spectrum of the South China Sea and the buoy’s absorption power spectrum. An objective function which combines these two spectra is established to reflect the energy absorbing efficiency. By applying Taguchi design, the frequency domain hydrodynamic analysis and the response surface method (RSM), the radius, cone angle and draft of the buoy are optimized. Since the significant influence of power take-off system (PTO) on energy absorption, the optimal PTO damping under random wave conditions is also studied. The optimal shape is acquired by maximizing the energy absorbing efficiency. Four types of performance and the influence of each geometrical parameter are also obtained. In addition, the cause of the trend of performance as well as the effects of adjusting the input parameters are analyzed. This study can provide guidance for the shape optimization of multi-parameter buoys.
15
Saeed, Shagufta, Sibtain Ahmed, Fatima Qureshi, Muhammad Sheraz Yasin, Rida Waseem, and Tahir Mehmood. "Bioconversion of mango peels into itaconic acid through submerged fermentation and statistical optimization of parameters through response surface methodology." PeerJ 12 (October 18, 2024): e18188. http://dx.doi.org/10.7717/peerj.18188.
Full textAbstract:
Itaconic acid is an industrially crucial organic acid due to its broad range of applications. The main hurdle in itaconic acid production is the high cost of the substrate, i.e., pure glucose, required for the fermentation process. Pakistan annually produces about 1.7 to 1.8 million metric tonnes of mango fruit. Keeping this in view, the potential of a sugar-rich fruit by-product, i.e., mango peels, was analyzed to be used as a substrate for the biosynthesis of itaconic acid using Aspergillus niger by submerged fermentation. Different physicochemical parameters (incubation period, temperature, agitation rate, inoculum size, and pH) were optimized using the central composite design (CCD) design of response surface methodology (RSM). The maximum production of itaconic acid, i.e., 4.6 g/L, was analyzed using 10% mango peels w/v (water hydrolysate), 3 mL inoculum volume after 5 days of fermentation period at pH 3, and a temperature of 32 °C when the media was kept at a 200-rpm agitation speed. The itaconic acid extraction from mango peels was done using the solvent extraction method using n-butanol. The identification and quantification of itaconic acid produced in the study were done using the Fourier Transform Infrared Spectroscopy (FTIR) spectrum and the High-Performance Liquid Chromatography (HPLC) method. According to HPLC analysis, 98.74% purity of itaconic acid was obtained in the research. Hence, it is concluded from the results that sugar-rich mango peels can act as a promising substrate for the biosynthesis of itaconic acid. Further conditions can be optimized at the bioreactor level to meet industrial requirements.
16
Zhang, Yajing, Zirui Zhao, Wenlong Li, Yuanhu Tang, Huiwen Meng, and Shujie Wang. "Separation and Purification of Taxanes from Crude Taxus cuspidata Extract by Antisolvent Recrystallization Method." Separations 9, no. 10 (2022): 304. http://dx.doi.org/10.3390/separations9100304.
Full textAbstract:
Taxanes are natural compounds with strong antitumor activity. In this study, we first enriched taxanes by ultrasonic extraction and liquid–liquid extraction from Taxus cuspidata, then purified these taxanes by the antisolvent recrystallization method, and discussed the effects of four recrystallization conditions on the purity of eight target compounds. The most promising purification results were obtained using methanol as a solvent and water as an antisolvent. Response surface methodology (RSM) was used to further optimize the optimal purification conditions: when the crude extraction concentration was 555.28 mg/mL, an antisolvent to solvent volume ratio was 28.16 times, the deposition temperature was 22.91 °C, and the deposition time was 1.76 min, the purity of the taxanes reached its maximum. The scanning electron microscopy (SEM) results showed that recrystallization could effectively reduce the particle size of crude Taxus cuspidata and control the particle morphology. X-ray diffraction (XRD) and Raman spectrum experiments demonstrated that the amorphous state of the crude Taxus cuspidata did not change during the recrystallization process, and always remained amorphous. This recrystallization method can effectively improve the purity of taxanes in Taxus cuspidata, and is suitable for the preliminary purification of taxanes.
17
Tang, Yang, Jingwen Bai, Yu Yang, et al. "Effect of Syringopicroside Extracted from Syringa oblata Lindl on the Biofilm Formation of Streptococcus suis." Molecules 26, no. 5 (2021): 1295. http://dx.doi.org/10.3390/molecules26051295.
Full textAbstract:
Syringopicroside is a natural drug with antibacterial activity, which is the main ingredient of Syringa oblata Lindl (S. oblata). In order to further develop the application of S. oblata and evaluate the ability of syringopicroside against Streptococcus suis (S. suis), this investigation first applied an ultrasonic-assisted method to extract syringopicroside, and then response surface methodology (RSM) was performed to get the optimum condition. Based on RSM analysis, a second-order polynomial equation about the syringopicroside yield and four variables, including ultrasonic power, time, temperature, and liquid-to-solid ratio, was purposed. Through RSM prediction and model verification experiments, the optimum conditions were determined, as follows: ultrasonic time was 63 min, temperature was 60 °C, a liquid-to-solid ratio was set to 63 mL/g, and ultrasonic power was 835 W. Under this condition, a high syringopicroside yield was obtained (3.07 ± 0.13 mg/g), which was not significantly different with a predicated value. After separation and purification by HPD 500 microporous resin, then mass spectrum was applied to identify the main ingredient in aqueous extract. A minimal inhibitory concentration (MIC) assay revealed the value against S. suis of syringopicroside was 2.56 µg/µL and syringopicroside with sub-inhibitory concentrations that could effectively inhibit biofilm formation of S. suis. Besides, scanning electron microscopy analysis indicated syringopicroside could destroy the multi-layered aggregation structure of S. suis. Finally, molecular docking analysis confirmed that syringopicroside was combined with Orfy protein of S. suis through hydrogen bonds, hydrophobic interaction, and π-π stacking.
18
Eka Saputra, Nugraha, and Yulita Arni Priastiwi. "Comparative Study Of Dynamic Earthquake Analysis With Spectral Design And Time History Methods." Jurnal Indonesia Sosial Teknologi 4, no. 8 (2023): 1223–34. http://dx.doi.org/10.59141/jist.v4i8.700.
Full textAbstract:
Earthquakes are natural events that cannot be prevented by humans and their occurrence is very difficult to predict. In civil engineering, especially in the structural field, earthquake loads are a major problem in planning economical and safe building structures. This study aims to determine the comparison of earthquake structures with the Response Spectrum, Response Spectrum Matched, Time Histories, and Time Histories Matched methods on the magnitude of the natural vibration period of the structure, the basic shear force, mass participation, displacement, and deviation between levels. The results of this study that the period of natural vibration of the structure with the earthquake method RS 1.412 seconds, RSM 1.453 seconds, TH 1.453 seconds, and THM 1.453 seconds is between the lower limit of 1.054 seconds and the upper limit of 1.476 seconds, so it meets the requirements of SNI 1726:2019. The results of the base shear analysis showed that dynamic analysis is greater than static and the structural model meets the requirements that VDynamics > 100%. VStatic. The results of the analysis of building mass participation in various earthquake methods meet the provisions with results of more than 90%. The results of the analysis of displacements are obtained for the x-direction, the largest THM is 41.945 mm and for the y-direction, TH is 57.330 mm. The results of the drift ratio analysis are obtained for the results of the y-direction drift which is greater than the x-direction drift and permit control for all earthquake methods is safe and meets the requirements of SNI 1726:2019.
19
El Adnany, El Mustapha, Najat Elhadiri, Ayoub Mourjane, et al. "Impact and Optimization of the Conditions of Extraction of Phenolic Compounds and Antioxidant Activity of Olive Leaves (Moroccan picholine) Using Response Surface Methodology." Separations 10, no. 6 (2023): 326. http://dx.doi.org/10.3390/separations10060326.
Full textAbstract:
The Moroccan picholine tree’s leaves contain phenolic compounds that benefit human health. However, the amount and type of these compounds can vary based on factors such as the extraction method and conditions. This study aimed to improve phenolic compounds’ extraction while minimising harmful chemicals’ use. It has been found that using ethanol as a solvent with ultrasonic extraction is the most effective and environmentally friendly technique. Several parameters, such as the extraction time, solid/solvent ratio, and ethanol concentration as independent variables, were evaluated using a surface response method (RSM) based on the Box–Behnken design (BBD) to optimize the extraction conditions. The experimental data were fitted to a second-order polynomial equation using multiple regression analysis and also examined using the appropriate statistical methods. In optimal conditions, the ultrasonic time, the ratio (solvent/solid) and the concentration (ethanol/water), the content of total polyphenols (TPC), total flavonoids (TFC), and antioxidant activity (by DPPH, ABTS, FRAP) were, respectively, 74.45 ± 1.22 mg EAG/g DM, 17.08 ± 1.85 mg EC/g DM, 83.45 ± 0.89% 82.85 ± 1.52%, and 85.01 ± 2.35%. The identification of phenolic compounds by chromatography coupled with mass spectrum (HPLC-MS) under optimal conditions with two successive extractions showed the presence of hydroxytyrosol, catechin, caffeic acid, vanillin, naringin, oleuropein, quercetin, and kaempferol at high concentrations.
20
Kim, Hyemi, Hyeongyeong Kim, Yejin Ahn, et al. "The Preparation and Physiochemical Characterization of Tenebrio molitor Chitin Using Alcalase." Molecules 28, no. 7 (2023): 3254. http://dx.doi.org/10.3390/molecules28073254.
Full textAbstract:
Chitin is mostly produced from crustaceans, but it is difficult to supply raw materials due to marine pollution, and the commonly used chemical chitin extraction method is not environmentally friendly. Therefore, this study aims to establish a chitin extraction process using enzymes and to develop edible insect-derived chitin as an eco-friendly new material. The response surface methodology (RSM) was used to determine the optimal conditions for enzymatic hydrolysis. The optimal conditions for enzymatic hydrolysis by RSM were determined to be the substrate concentration (7.5%), enzyme concentration (80 μL/g), and reaction time (24 h). The solubility and DDA of the mealworm chitosan were 45% and 37%, respectively, and those of the commercial chitosan were 61% and 57%, respectively. In regard to the thermodynamic properties, the exothermic peak of mealworm chitin was similar to that of commercial chitin. In the FT-IR spectrum, a band was observed in mealworm chitin corresponding to the C=O of the NHCOCH3 group at 1645 cm−1, but this band showed low-intensity C=O in the mealworm chitosan due to deacetylation. Collectively, mealworm chitosan shows almost similar physical and chemical properties to commercial chitosan. Therefore, it is shown that an eco-friendly process can be introduced into chitosan production by using enzyme-extracted mealworms for chitin/chitosan production.
21
Jiang, Hongqi, and Shuncai Li. "The Wind-Induced Vibration Response for Tower Crane Based on Virtual Excitation Method." Open Mechanical Engineering Journal 8, no. 1 (2014): 201–5. http://dx.doi.org/10.2174/1874155x01408010201.
Full textAbstract:
The dynamics of Tower Crane is complicated by wind excitation which complicates the wind-induced vibration response analysis. The random wind-induced response analysis of tower crane is presented based on finite element method and virtual excitation method. The pulsating wind loads change into multiple-point correlation stationary excitation. This paper uses Davenport’s wind speed spectrum which does not change with height, and considers multiplepoint correlation of wind-induction. The tower crane was employed as a numerical example; the response spectra and Mean Square Root (RMS) of the tower crane were obtained by wind-induced vibration. The results indicate that the vibration of the tower crane showed a greater response in low frequency with the One-third Octave acceleration RMS being lower. Finally, the influences of the wind-induced vibration on comfort were analyzed.
22
Yadav, Mr Rajesh Kumar. "Seismic Analysis of Lightweight and Conventional Buildings: A Comparative Study." International Journal for Research in Applied Science and Engineering Technology 9, no. 10 (2021): 1079–83. http://dx.doi.org/10.22214/ijraset.2021.38500.
Full textAbstract:
Abstract: In recent decades, the use of light-weight materials over heavy-weight materials has increased at a faster rate. When it comes to cost and resource savings, lightweight construction is considered to be more essential. AAC block is a lightweight construction material that provides good acoustic and thermal insulation. In seismic zones, the use of lightweight materials in building reduces the percentage of damages. The goal of this research is to conduct a project comparison study of seismic analysis of buildings composed of lightweight and conventional materials. RSM creates a structural model of a multi-story structure (G+3) and analyses it in Etabs (Response Spectrum Method). Buildings constructed using infill AAC (Autoclaved aerated concrete) blocks and traditional clay brick masonry are designed for the same seismic hazard in conformity with Indian norms. The buildings' analytical results will be compared. The project also aims to familiarise students with Etabs2016. Keywords: Autoclaved Aerated Concrete, Conventional Brick Replacement, Lightweight Construction, Lightweight Material.
23
Sumit, S. Khandare, and P. Jaiswal Shyamali. "Comparative Study of Seismic Analysis of Building with Light Weight and Conventional Material." International Journal of Engineering and Management Research 9, no. 2 (2019): 162–65. https://doi.org/10.31033/ijemr.9.2.21.
Full textAbstract:
In recent decades, the lightweight materials are used in construction instead of conventional material. Lightweight construction is considered to be favourable due to the saving in construction cost and materials. AAC block is a lightweight structural material with excellent acoustic and thermal insulation properties. Due to the use of lightweight material in construction in seismic zone reduce the percentage of damages. In this paper the attempt has been made to carry out the project comparative study of seismic analysis of building with lightweight and conventional material. Structural model of multi storey building (G+3) and analysis is carried out in STAAD-Pro by RSM (Response Spectrum Method). Building using infill AAC (Autoclaved aerated concrete) block and conventional clay brick masonry are designed for the same seismic hazard in accordance with the applicable provisions given in Indian codes. The analytical results of the buildings will be compared. The project is also aimed at getting familiarity with STAAD-Pro.2008.
24
Setiowati, Arima Diah, Elita Yeliani, and Chusnul Hidayat. "Whey Protein-Pectin Conjugate by Wet-Dry Heating: Optimization using Response Surface Methodology with Box-Behnken Design." agriTECH 43, no. 4 (2023): 297. http://dx.doi.org/10.22146/agritech.71301.
Full textAbstract:
The recent progress in glycation of proteins utilizing saccharides through the Maillard reaction has garnered substantial attention, with a specific emphasis on Whey Protein Concentrate (WPC). Conjugation mode is frequently intricate and poses challenges when scaling up for large-scale production. Consequently, this investigation sought to optimize the conditions of the WPC-pectin conjugation process using Response Surface Methodology (RSM) in conjunction with Box-Behnken design (BBD). The experimentation was executed employing a cabinet dryer, incorporating both wet and dry heating procedures to yield a WPC-pectin conjugate exhibiting favorable functional properties. The independent variables investigated encompassed pectin concentration (ranging from 0 to 1%), pH (ranging from 6 to 8), and drying time (ranging from 2 to 6 hours), The measured responses encompassed the emulsion stability index (ESI), emulsifying activity index (EAI), and solubility. Analyzing the experimental data underwent scrutiny for model sufficiency through diagnostic plots, and a second-order polynomial equation was fitted through multi-response regression analysis, resulting in a high coefficient of determination (R 2 ) value. The most effective parameters were identified as a pectin concentration of 0.49%, pH 6.7, and a drying duration of 4.12 hours, yielding a peak ESI of 452.267 minutes, EAI measuring 49.95 m 2 g -1 , and solubility reaching 48.09%. Further experiments were conducted to validate these outcomes, and the presence of the Maillard reaction was confirmed using Fourier Transform Infrared Spectrum (FTIR). The et-dry method demonstrated efficacy in producing WPCpectin conjugates with commendable functional properties.
25
García-Beleño, Jeniffer, and Eduardo Rodríguez de San Miguel. "Integration of Response Surface Methodology (RSM) and Principal Component Analysis (PCA) as an Optimization Tool for Polymer Inclusion Membrane Based-Optodes Designed for Hg(II), Cd(II), and Pb(II)." Membranes 11, no. 4 (2021): 288. http://dx.doi.org/10.3390/membranes11040288.
Full textAbstract:
An optimization of the composition of polymer inclusion membrane (PIM)-based optodes, and their exposure times to metal ion solutions (Hg(II), Cd(II), and Pb(II)) was performed using two different chromophores, diphenylthiocarbazone (dithizone) and 1-(2-pyridylazo)-2-naphthol (PAN). Four factors were evaluated (chromophore (0.06–1 mg), cellulose triacetate (25–100 mg) and plasticizer amounts (25–100 mg), and exposure time (20–80 min)). Derringer’s desirability functions values were employed as response variables to perform the optimization obtained from the results of three different processes of spectral data treatment: two full-spectrum methods (M1 and M3) and one band-based method (M2). The three different methods were compared using a heatmap of the coefficients and dendrograms of the Principal Component Analysis (PCA)reductions of their desirability functions. The final recommended M3 processing method, i.e., using the scores values of the first two principal components in PCA after subtraction of the normalized spectra of the membranes before and after complexation, gave more discernable differences between the PIMs in the Design of Experiments (DoE), as the nodes among samples appeared at longer distances and varyingly distributed in the dendrogram analysis. The optimal values were time of 35–65 min, 0.53 mg–1.0 mg of chromophores, plasticizers 34.4–71.9 of chromophores, and 62.5–100 mg of CTA, depending on the metal ion. In addition, the method yielded the best outcomes in terms of interpretability and an easily discernable color change so that it is recommended as a novel optimization method for this kind of PIM optode.
26
K., Udaya Sri, S. N. Murthy B, and Mohan Rao N. "Monitoring Exhaust Emissions of A Direct Injection Diesel Engine Fueled With Linseed Oil Biodiesel - Hydrogen Dual Fuel." International Journal of Innovative Technology and Exploring Engineering (IJITEE) 10, no. 6 (2021): 42–49. https://doi.org/10.35940/ijitee.F8765.0410621.
Full textAbstract:
This study presents an experimental and analytical investigation on the effects of using methyl ester of linseed oil (MELO)-diesel blend of B10, B20, and B30 with hydrogen injection of 5%, 10%, and 15% in a VCR (Variable Compression Ratio) diesel engine, operated with the compression ratios (CRs) of 15, 16, 17, and 18 on DFM (duel fuel mode). This study also gives emphasis on the optimized emissions of CO, CO2, NO, and smoke, when the engine was operated with MELO-diesel blends, and hydrogen injections with the variation in engine load, crank angle (CA), using response surface methodology (RSM) with the help of MINITAB programming. During the analysis it was observed that the emissions of CO, CO2, O2, NO, and smoke were found to be a function of biodiesel blends, compression ratios, load, and percentage of hydrogen injection. The research results report that, the dual fuel mode of diesel MELO 20% blend with hydrogen injection of about 10% gave optimized results in terms of performance and exhaust emissions, while the optimized CR was 17. The engine was smoothly operated with B20-H10-CR17 over lower emissions compared to diesel, throughout the load spectrum.
27
Ran, Junjian, Youzhi Wu, Bo Zhang, et al. "Paenibacillus polymyxa Antagonism towards Fusarium: Identification and Optimisation of Antibiotic Production." Toxins 15, no. 2 (2023): 138. http://dx.doi.org/10.3390/toxins15020138.
Full textAbstract:
An antibiotic produced by Paenibacillus polymyxa 7F1 was studied. The 7F1 strain was isolated from the rhizosphere of a wheat field. Response surface methodology was used to optimize the physicochemical parameters. The strain showed broad-spectrum activity against several plant pathogens. Identification of the strain was realized based on 16s rRNA gene and gyrB gene sequencing. The antibiotic was optimized by one-factor-at-a-time (OFAT) and response surface methodology (RSM) approaches. The suitable antibiotic production conditions were optimized using the one-factor-at-a-time method. The individual and interaction effects of three independent variables: culture temperature, initial pH, and culture time, were optimized by Box-Behnken design. The 16SrRNA gene sequence (1239 nucleotides) and gyrB gene (1111 nucleotides) were determined for strain 7F1 and shared the highest identities to those of Paenibacillus polymyxa. The results showed the optimal fermentation conditions for antibiotics produced by Paenibacillus polymyxa 7F1 were a culture temperature of 38 °C, initial pH of 8.0, and culture time of 8 h. The antibiotics produced by Paenibacillus polymyxa 7F1 include lipopeptides such as iturin A and surfactin. The results provide a theoretical basis for the development of bacteriostatic biological agents and the control of mycotoxins.
28
Pandey, Akash Vijay, Er Bajrang Ambhore, and Prof Pallavi N. Bhende. "Comparative Study of Seismic Analysis of Vertically Irregular R.C. Frame Using Indian and Euro Code." International Journal for Research in Applied Science and Engineering Technology 13, no. 5 (2025): 1192–200. https://doi.org/10.22214/ijraset.2025.70366.
Full textAbstract:
Abstract:The present study conducts a comparative evaluation of the seismic performance of reinforced concrete (RC) building frames designed in accordance with two globally accepted design codes: the Indian Standard (IS 1893:2016) and the European Standard (Eurocode 8). Structures with vertical irregularities are known to be more susceptible to seismic damage, particularly when appropriate strength and detailing measures are not implemented. High-rise buildings, especially those exhibiting geometric discontinuities, require a comprehensive assessment of their seismic response to ensure safety and resilience. This research investigates a G+22 storey RC building characterized by vertical geometric irregularities. The seismic analysis is carried out using ETABS software, employing the Response Spectrum Method (RSM) to evaluate structural response parameters, including storey drift, overturning moment, storey shear, and lateral displacement in both principal directions. The study highlights the practical differences between the two codes by comparing their design implications. In particular, it is observed that structures analyzed under IS 1893 tend to exhibit relatively lower response values that remain within acceptable limits, whereas Eurocode 8 analysis results in higher seismic demand due to its detailed spectral definitions and consideration of site-specific soil characteristics. This comparison underlines that IS 1893 offers a more conservative design approach, particularly beneficial for seismically active regions. The research further emphasizes the relevance of adopting international standards, such as Eurocode 8, for improving construction practices and enhancing structural safety in regions influenced by global construction norms, including the Gulf countries.
29
Rhea, Carter Lee, Julie Hlavacek-Larrondo, Alexandre Adam, et al. "Deconvolving X-Ray Galaxy Cluster Spectra Using a Recurrent Inference Machine." Astronomical Journal 169, no. 5 (2025): 268. https://doi.org/10.3847/1538-3881/adbf7b.
Full textAbstract:
Abstract Recent advances in machine learning algorithms have unlocked new insights in observational astronomy by allowing astronomers to probe new frontiers. In this article, we present a methodology to disentangle the intrinsic X-ray spectrum of galaxy clusters from the instrumental response function. Employing state-of-the-art modeling software and data mining techniques of the Chandra data archive, we construct a set of 100,000 mock Chandra spectra. We train a Recurrent Inference Machine (RIM) to take in the instrumental response and mock observation and output the intrinsic X-ray spectrum. The RIM can recover the mock intrinsic spectrum below the 1σ error threshold; moreover, the RIM reconstruction of the mock observations is indistinguishable from the observations themselves. To further test the algorithm, we deconvolve extracted spectra from the central regions of the galaxy group NGC 1550, known to have a rich X-ray spectrum, and the massive galaxy clusters A1795. Despite the RIM reconstructions consistently remaining below the 1σ noise level, the recovered intrinsic spectra did not align with modeled expectations. This discrepancy is likely attributable to the RIM’s method of implicitly encoding prior information within the neural network. This approach holds promise for unlocking new possibilities in accurate spectral reconstructions and advancing our understanding of complex X-ray cosmic phenomena.
30
Es-haghi, Ali, Mohammad Ehsan Taghavizadeh Yazdi, Mohammad Sharifalhoseini, et al. "Application of Response Surface Methodology for Optimizing the Therapeutic Activity of ZnO Nanoparticles Biosynthesized from Aspergillus niger." Biomimetics 6, no. 2 (2021): 34. http://dx.doi.org/10.3390/biomimetics6020034.
Full textAbstract:
In this study, the biosynthesis of zinc oxide nanoparticles using Aspergillus niger (A/ZnO-NPs) is described. These particles have been characterized by UV–Vis spectrum analysis, X-ray powder diffraction, field emission scanning electron microscopy, and transmission electron microscopy. To use this biosynthesized nanoparticle as an antiproliferative and antimicrobial agent, the IC50 value against the breast cancer cell line and inhibition zone against Escherichia coli were used to optimize the effect of two processing factors including dose of filtrate fungi cell and temperature. The biosynthesized A/ZnO-NPs had an absorbance band at 320 nm and spherical shapes. The mean particles size was 35 nm. RSM (response surface methodology) was utilized to investigate the outcome responses. The Model F-value of 12.21 and 7.29 implies that the model was significant for both responses. The contour plot against inhibition zone for temperature and dose showed that if the dose increases from 3.8 to 17.2 µg/mL, the inhibition zone increases up to 35 mm. As an alternative to chemical and/or physical methods, biosynthesizing zinc oxide NPs through fungi extracts can serve as a more facile and eco-friendly strategy. Additionally, for optimization of the processes, the outcome responses in the biomedical available test can be used in the synthesis of ZnO-NPs that are utilized for large-scale production in various medical applications.
31
Çelik, Saffet, Naciye Kutlu, Yusuf Can Gerçek, Sinan Bayram, Ravi Pandiselvam, and Nesrin Ecem Bayram. "Optimization of Ultrasonic Extraction of Nutraceutical and Pharmaceutical Compounds from Bee Pollen with Deep Eutectic Solvents Using Response Surface Methodology." Foods 11, no. 22 (2022): 3652. http://dx.doi.org/10.3390/foods11223652.
Full textAbstract:
In recent years, there has been increasing interest in green extraction methods and green solvents due to their many advantages. In this study, the effects of an ultrasonic extraction method and deep eutectic solvents (DESs) on the extraction of different bioactive substances from bee pollen were investigated. In this regard, the effects of process variables such as the molar ratio of the DES (1, 1.5, and 2), sonication time (15, 30, and 45 min), and ultrasonic power (90, 135 and 180 W) on total individual amino acids, total individual organic acids, and total individual phenolic compounds were investigated by response surface methodology (RSM). The optimal conditions were found to be a molar ratio of 2, sonication time of 45 min, and ultrasonic power of 180 W (R2 = 0.84). Extracts obtained via the maceration method using ethanol as a solvent were evaluated as the control group. Compared with the control group, the total individual amino acid and total individual organic acid values were higher using DESs. In addition, compounds such as myricetin, kaempferol, and quercetin were extracted at higher concentrations using DESs compared to controls. The results obtained in antimicrobial activity tests showed that the DES groups had broad-spectrum antibacterial effects against all bacterial samples, without exception. However, in yeast-like fungus samples, this inhibition effect was negligibly low. This study is the first to evaluate the impact of DESs on the extraction of bioactive substances from bee pollen. The obtained results show that this innovative and green extraction technique/solvent (ultrasonic extraction/DES) can be used successfully to obtain important bioactive compounds from bee pollen.
32
Pappas, Dimitri, Tiffany L. Correll, Nathan C. Pixley, Benjamin W. Smith, and J. D. Winefordner. "Detection of Mie Scattering Using a Resonance Fluorescence Monochromator." Applied Spectroscopy 56, no. 9 (2002): 1237–40. http://dx.doi.org/10.1366/000370202760295502.
Full textAbstract:
The use of a resonance fluorescence monochromator (RFM) is described as a method for detecting Mie scatter. The detector has a spectral resolution limited by the atomic vapor used in the system (400 MHz for cesium). The RFM is used to detect Mie scatter from a particulate suspension, and deconvolution methods are used to extract the Mie scatter spectrum from the instrument response. The Mie scattering linewidth (140 MHz) is close to the literature value (100 MHz for air). Methods to reduce the linewidth of atomic vapor filters are briefly described.
33
Wan Ikhsan, Syarifah Nazirah Wan, Norhaniza Yusof, Farhana Aziz, et al. "Synthesis and Optimization of Superhydrophilic-Superoleophobic Chitosan–Silica/HNT Nanocomposite Coating for Oil–Water Separation Using Response Surface Methodology." Nanomaterials 12, no. 20 (2022): 3673. http://dx.doi.org/10.3390/nano12203673.
Full textAbstract:
In this current study, facile, one-pot synthesis of functionalised nanocomposite coating with simultaneous hydrophilic and oleophobic properties was successfully achieved via the sol–gel technique. The synthesis of this nanocomposite coating aims to develop a highly efficient, simultaneously oleophobic-hydrophilic coating intended for polymer membranes to spontaneously separate oil-in-water emulsions, therefore, mitigating the fouling issue posed by an unmodified polymer membrane. The simultaneous hydrophilicity-oleophobicity of the nanocoating can be applied onto an existing membrane to improve their capability to spontaneously separate oil-in-water substances in the treatment of oily wastewater using little to no energy and being environmentally friendly. The synthesis of hybrid chitosan–silica (CTS-Si)/halloysite nanotube (HNT) nanocomposite coating using the sol–gel method was presented, and the resultant coating was characterised using FTIR, XPS, XRD, NMR, BET, Zeta Potential, and TGA. The wettability of the nanocomposite coating was evaluated in terms of water and oil contact angle, in which it was coated onto a polymer substrate. The coating was optimised in terms of oil and water contact angle using Response Surface Modification (RSM) with Central Composite Design (CCD) theory. The XPS results revealed the successful grafting of organosilanes groups of HNT onto the CTS-Si denoted by a wide band between 102.6–103.7 eV at Si2p. FTIR spectrum presented significant peaks at 3621 cm−1; 1013 cm−1 was attributed to chitosan, and 787 cm−1 signified the stretching of Si-O-Si on HNT. 29Si, 27Al, and 13H NMR spectroscopy confirmed the extensive modification of the particle’s shells with chitosan–silica hybrid covalently linked to the halloysite nanotube domains. The morphological analysis via FESEM resulted in the surface morphology that indicates improved wettability of the nanocomposite. The resultant colloids have a high colloid stability of 19.3 mV and electrophoretic mobility of 0.1904 µmcm/Vs. The coating recorded high hydrophilicity with amplified oleophobic properties depicted by a low water contact angle (WCA) of 11° and high oil contact angle (OCA) of 171.3°. The optimisation results via RSM suggested that the optimised sol pH and nanoparticle loadings were pH 7.0 and 1.05 wt%, respectively, yielding 95% desirability for high oil contact angle and low water contact angle.
34
Liu, Jinze, Jinyue Song, Fusheng Gao, et al. "Extraction, Purification, and Structural Characterization of Polysaccharides from Sanghuangporus vaninii with Anti-Inflammatory Activity." Molecules 28, no. 16 (2023): 6081. http://dx.doi.org/10.3390/molecules28166081.
Full textAbstract:
In order to obtain homogeneous Sanghuangporus vaninii polysaccharides with antioxidant and anti-inflammatory activities, a response surface method (RSM) was used to compare the polysaccharide extraction rate of hot water extraction and ultrasonic-assisted extraction from Sanghuangporus vaninii. The optimal conditions for ultrasonic-assisted extraction were determined as follows: an extraction temperature of 60 °C, an extraction time of 60 min, a solid–liquid ratio of 40 g/mL, and an ultrasonic power of 70 W. An SVP (Sanghuangporus vaninii polysaccharides) extraction rate of 1.41% was achieved. Five homogeneous monosaccharides were obtained by gradient ethanol precipitation with diethylaminoethyl–cellulose (DEAE) and SephadexG-100 separation and purification. The five polysaccharides were characterized by high performance liquid chromatography, the ultraviolet spectrum, the Fourier transform infrared spectrum, TG (thermogravimetric analysis), the Zeta potential, and SEM (scanning electron microscopy). The five polysaccharides had certain levels of antioxidant activity in vitro. In addition, we the investigated the anti-inflammatory effects of polysaccharides derived from Sanghuangporus vaninii on lipopolysaccharide (LPS)-induced RAW 264.7 cells and Kupffer cells. Further, we found that SVP-60 significantly inhibited the levels of pro-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in lipopolysaccharide (LPS)-induced RAW 264.7 cells and promoted the level of the anti-inflammatory cytokine IL-10 in lipopolysaccharide (LPS)-induced RAW 264.7 cells. Our study provides theoretical support for the potential application of Sanghuangporus vaninii in the field of antioxidant and anti-inflammatory activities in vitro.
35
Gao, Guohua, Jeroen C. Vink, Faruk O. Alpak, and W. Mo. "An Efficient Optimization Work Flow for Field-Scale In-Situ Upgrading Developments." SPE Journal 20, no. 04 (2015): 701–16. http://dx.doi.org/10.2118/2014-1885283-pa.
Full textAbstract:
Summary In-situ upgrading process (IUP) is an attractive technology for developing unconventional extraheavy-oil reserves. Decisions are generally made on field-scale economics evaluated with dedicated commercial tools. However, it is difficult to conduct an automated IUP optimization process because of unavailable interface between the economic evaluator and commercial simulator/optimizer, and because IUP is such a highly complex process that full-field simulations are generally not feasible. In this paper, we developed an efficient optimization work flow by addressing three technical challenges for field-scale IUP developments. The first challenge was deriving an upscaling factor modeled after analytical superposition formulation; proposing an effective method of scaling up simulation results and economic terms generated from a single-pattern IUP reservoir-simulation model to field scale; and validating this approach numerically. The second challenge was proposing a response-surface model (RSM) of field economics to analytically compute key field economical indicators, such as net present value (NPV), by use of only a few single-pattern economic terms together with the upscaling factor, and validating this approach with a commercial tool. The proposed RSM approach is more efficient, accurate, and convenient because it requires only 15–20 simulation cases as training data, compared with thousands of simulation runs required by conventional methods. The third challenge is developing a new optimization method with many attractive features: well-parallelized, highly efficient and robust, and with a much-wider spectrum of applications than gradient-based or derivative-free methods, applicable to problems without any derivative, with derivatives available for some variables, or with derivatives available for all variables. This work flow allows us to perform automated field IUP optimizations by maximizing a full-field economics target while honoring all field-level facility constraints effectively. We have applied the work flow to optimize the IUP development of a carbonate heavy-oil asset. Our results show that the approach is robust and efficient, and leads to development options with a significantly improved field-scale NPV. This work flow can also be applied to other kinds of pattern-based field developments of shale gas and oil, and thermal processes such as steamdrive or steam-assisted gravity drainage.
36
Maher, Tahani, Nassereldeen A. Kabbashi, Mohamed E. S. Mirghani, et al. "Optimization of Ultrasound-Assisted Extraction of Bioactive Compounds from Acacia Seyal Gum Using Response Surface Methodology and Their Chemical Content Identification by Raman, FTIR, and GC-TOFMS." Antioxidants 10, no. 10 (2021): 1612. http://dx.doi.org/10.3390/antiox10101612.
Full textAbstract:
Acacia Seyal gum (ASG), also known as gum Arabic, is an antioxidant-rich soluble fiber. ASG has been reported to have many biological activities, including anticancer, antidiabetic, antiulcer, and immunomodulatory activity. Extraction of bioactive compounds from ASG is commonly performed using conventional extraction methods. However, these techniques have certain limitation in terms of extraction time, energy, and solvent requirements. Ultrasound-assisted extraction (UAE) could be used as an alternative technique to extract bioactive compounds in less time, at low temperature, and with less energy and solvent requirements. In this study, the UAE extraction of ASG was optimized using response surface methodology (RSM). A face-centered central composite design (FCCCD) was used to monitor the effect of different independent factors of ultrasound operation (sonication time, temperature, and solvent ratio) on ASG extraction yield. In addition, screening and characterization of phytochemicals in 60% ethanol ASG extract was carried out using Raman microscopy, Fourier transform infrared spectroscopy (FTIR), and gas chromatography time-of-flight mass spectroscopy (GC-TOFMS) analysis. The results indicated that, under optimal conditions (extraction time 45 min, extraction temperature 40 °C, and solid–liquid ratio of 1:25 g/mL), the yield of ASG was 75.87% ± 0.10. This yield was reasonably close to the predicted yield of 75.39% suggested by the design of experiment. The ANOVA revealed that the model was highly significant due to the low probability value (p < 0.0001). Raman spectrum fingerprint detected polysaccharides, such as galactose and glucose, and protein like lysine and proline, while FTIR spectrum revealed the presence of functional groups peaks value of alkanes, aldehydes, aliphatic amines, and phenol. GC-TOFMS spectroscopic detected the presence of strong d-galactopyranose, carotenoid, and lycopene antioxidant compounds. In conclusion, this study demonstrated that the UAE technique is an efficient method to achieve a high yield of ASG extracts. The selected model is adequate to optimize the extraction of several chemical compounds reported in this study.
37
Ong, Mei Yin, and Saifuddin Nomanbhay. "Optimization Study on Microwave-Assisted Hydrothermal Liquefaction of Malaysian Macroalgae Chaetomorpha sp. for Phenolic-Rich Bio-Oil Production." Energies 15, no. 11 (2022): 3974. http://dx.doi.org/10.3390/en15113974.
Full textAbstract:
There are several methods of biomass conversion, including hydrothermal liquefaction (HTL). The implementation of microwave technology in the HTL process is still new, especially on the conversion of marine biomass into bio-crude. In this work, the macroalgae Chaetomorpha sp. was used as the biomass feedstock to produce phenolic-rich bio-oil through microwave-assisted HTL. Chaetomorpha sp. was abundantly found in Malaysia, creating a green tides issue. By utilizing these algae, the green tide issue can be solved and value-added bio-oil is obtained. However, bio-oil from macroalgae has a relatively low heating value, restricting its fuel application. Therefore, it is suggested to be used for bio-polymer synthesis, including bio-based phenol formaldehyde. In this study, the effect of different parameters, such as reaction temperature, preloaded pressure, water-to-algal biomass ratio, and holding time, on both the bio-oil yield and phenolic yield was evaluated. Folin–Ciocalteu method was introduced as the phenolic determination method and the optimal conditions were located by using Response Surface Methodology (RSM). As a results, an optimal biodiesel yield and phenolic yield of 21.47 wt% and 19.22 wt% Gallic Acid Equivalent was obtained at a reaction temperature of 226 °C, 42 bar preloaded pressure and 30:1 water-to-algal biomass ratio after 79 min. Sensitivity analysis also concluded that the water-to-algal biomass ratio is the most influential factor, followed by the preloaded pressure. The FTIR spectrum of the bio-oil produced indicated the presence of different functional group of compounds. In short, Chaetomorpha sp. has been successfully converted into valuable bio-oil through microwave-assisted HTL.
38
Hossain, Sabbir, and S. K. Singh. "Comparative analysis of irregular RCC buildings in different zones." IOP Conference Series: Earth and Environmental Science 1110, no. 1 (2023): 012035. http://dx.doi.org/10.1088/1755-1315/1110/1/012035.
Full textAbstract:
Abstract The earthquake is the most devastating and unexpected natural phenomenon, causing massive damage to both human lives and infrastructure. In this study, two different irregulars Reinforced Cement Concrete (RCC) building plans of 25th story buildings with the ground floor (G+25) and 9th storey buildings with the ground floor (G+9) were subjected to four different zones making a total of eight model structures to test their ability to withstand gravity and seismic loads. The design was response spectrum method (RSM) then subjected to an earthquake load in accordance with Indian Standard (IS) 1893. The earthquake performance is evaluated on the basis of the structure’s design, serviceability, and earthquake power using an extended three-dimensional analysis of building systems (ETABS). The behaviour of building irregularities under seismic loading is investigated in this work. In this study, it has been compared the results in terms of max story displacement, max story drifts, and base shear. It was found that the model in zone 5 has maximum story displacements among all other models as well as higher max story drifts and base shears for both plans of G+9 and G+25. From the result, it was concluded that both the building models in the lower zone showed better performance in terms of max story displacement, max story drift, and base shear.
39
Treetrong, Juggrapong. "Fault Prediction of Induction Motor Based on Time-Frequency Analysis." Applied Mechanics and Materials 52-54 (March 2011): 115–20. http://dx.doi.org/10.4028/www.scientific.net/amm.52-54.115.
Full textAbstract:
Because the faults happening in the motor (such as the stator and the rotor faults) can distort the sinusoidal response of the motor RPM and the main frequency, hence the spectrum method has previously been introduced which it relates to both amplitudes and phases among harmonics in a signal. The method popularly applied for fault detection is based on frequency analysis by observing the side band, its harmonics around main frequencies or its other harmonics. Based on the present experiments, the spectrum method by FFT function has ability to distinguish the motor condition. But, the fault severity levels seem to not able to analyze. Hence the time-frequency Analysis (or spectrogram) of the stator phase currents is proposed here. The method is expected to show relation between the phase current signals and the fault levels which make it can detect the faults and also indicate the fault levels. The experiments show that the proposed method can provide good accuracy for fault prediction and fault level quantification. Hence it can conclude that the propose method can be an effective tool for motor fault prediction.
40
Jiang, Bin, Jiaxin Na, Lele Wang, Dongmei Li, Chunhong Liu, and Zhibiao Feng. "Reutilization of Food Waste: One-Step Extration, Purification and Characterization of Ovalbumin from Salted Egg White by Aqueous Two-Phase Flotation." Foods 8, no. 8 (2019): 286. http://dx.doi.org/10.3390/foods8080286.
Full textAbstract:
For the purpose of reducing pollution and the reutilization of salted egg whites, which are byproducts of the manufacturing process of salted egg yolks and normally treated as waste, an aqueous two-phase flotation (ATPF) composed of polyethylene glycols (PEG 1000) and (NH4)2SO4 was applied to develop a simple, inexpensive and efficient process for the separation of ovalbumin (OVA) from salted egg whites. The effects of the concentration of PEG, the concentration of (NH4)2SO4, the flow rate and the flotation time on the flotation efficiency (Y) and purity (P) of OVA were investigated. A response surface method (RSM) experiment was carried out on the basis of a single-factor experiment. An efficient separation was achieved using ATPF containing 5 mL of 80% PEG 1000 (w/w), 28 mL of 28% (NH4)2SO4 (w/w), 35 mL/min of the flow rate and 30 min of the flotation time, while 2 mL of the salted egg white solution (salted eggs white (v): water (v) = 1:4) was loaded. Under the optimal conditions, Y and P of OVA could reach 82.15 ± 0.24% and 92.98 ± 0.68%, respectively. The purified OVA was characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), reverse phase high-performance liquid chromatography (RP-HPLC), liquid chromatography-nano electrospray ionisation mass spectrometry (Nano LC-ESI-MS/MS), ultraviolet spectrum (UV), fluorescence spectrum (FL) and fourier transform infrared spectroscopy (FT-IR). The results indicated that the purity of OVA obtained by ATPF was satisfactory and there was no obvious difference in the structure of the OVA separated by ATPF and the standard. The results of the functional properties revealed no significant differences between OVA obtained by ATPF and the standard in oil binding capacity, viscosity, emulsibility and foam capacity.
41
Gross, G. W. "Nitrates in ice: uptake; dielectric response by the layered capacitor method." Canadian Journal of Physics 81, no. 1-2 (2003): 439–50. http://dx.doi.org/10.1139/p02-143.
Full textAbstract:
Ice columns of 0.200.25 m length and 0.038 m diameter were grown in the laboratory from dilute solutions (105 to 102 N) of potassium, sodium, or ammonium nitrate at a constant freezing rate of 0.002 m h1 and stirring at 300 rpm. The distribution coefficient was computed at ~0.015 m intervals as the ratio of nitrate concentration in the melted ice and in the liquid phase as a function of interface position. The average distribution coefficients were (2.25 ± 0.55) × 104 for the potassium and sodium nitrate, and (6.1 ± 1.4) × 103 for the ammonium nitrate samples about a 27-fold increase. These results are in line with other large anions such as sulfate and methanesulfonate that were previously investigated. The dielectric relaxation spectrum of ice slices (~0.012 m thick and sandwiched between thin fluoroplastic foils) was measured between 1 and 85°C at frequencies from 1 Hz to 100 kHz with a lock-in amplifier technique. First, the ice response was recovered from the (MaxwellWagner) layered capacitor. The dielectric relaxation ranges were then separated and their characteristic parameters computed. The complex conductivity (Grant plot) and the conductivity frequency-response plot have been the most useful tools for this purpose. Both (alkali-metal and ammonium nitrate) sample groups exhibit the Debye dispersion of polar molecules so characteristic for ice regardless of impurity content. There is also a dispersion range at lower frequencies, and a static or quasi-static conductivity. In the alkali-metal nitrates the low-frequency dispersion is a prominent space-charge dispersion, and the temperature-dependent interaction between orientational and ionic point defects in the ice lattice leads to the conductivity crossover phenomenon. Ammonium greatly reduces the ionic lattice defects responsible for space charge and static conductivity; there is no crossover. Both the Debye dispersion and the crossover support the concept of co-operative responses by the polar molecules making up the ice substance to physico-chemical stimuli. PACS Nos.: 61.72, 77.22G, 77.22J, 81.30F
42
Sek, Michael A., Vincent Rouillard, and Anthony Parker. "Characterisation of the Nonlinear Behaviour of Expanded Polystyrene Cushions." Applied Mechanics and Materials 7-8 (August 2007): 283–88. http://dx.doi.org/10.4028/www.scientific.net/amm.7-8.283.
Full textAbstract:
There are two main characteristics of cushioning materials that are required to design a robust cushioning system for the protection of critical element against enviro-mechanical hazards: the attenuation of shocks as a function of the static load and the vibration transmissibility. The effect of a shock on a hypothetical critical element is normally evaluated by the Shock Response Spectrum (SRS) whereas the Frequency Response Function (FRF) performs similar function in relation to vibrations. This paper is concerned with the latter. Cushioning materials are generally nonlinear and, together with the interacting mass, form a nonlinear dynamic system. This paper shows how the Reverse Multiple Input-Single-Output (R-MISO) method can be used to describe the nonlinear characteristics of cushioning systems by generating a series of FRF terms. However, this creates ambiguity in relation to the effect of transmitted vibration on the critical element. This paper proposes to resolve this, by analogy to the SRS, through a numerical calculation of the Vibration Response Spectrum (VRS) for a hypothetical critical element, using as the excitation of the critical element either experimental cushion response data or data synthesised via R-MISO FRFs. Values of the VRS are defined as the ratio of acceleration rms of the critical element to the rms of the cushion excitation, although other descriptors of critical element's exertion can also be considered. The VRS can be considered as the true transmissibility. It is shown that the R-MISO method is superior over the Single Input-Single-Output (SISO) method in determining the transmissibility of polystyrene cushions. Since the cushion system is nonlinear, the excitation of the linear critical element will in general be non-Gaussian, although this paper has shown that it is near- Gaussian in the vicinity of cushion resonance. A chosen hypothetical critical element can be linear or, if its characteristics is known in advance, nonlinear. Results presented in this paper demonstrate how the R-MISO and the VRS can be used to determine the dynamic characteristics of EPS as a nonlinear cushioning material.
43
Pan, Xiao Dong, Jia En Zhong, and Chao Chao He. "Nonstationary Probabilistic Seismic Response Analysis of Nonlinear Soil Profile under Bidirectional Dynamic Loading." Applied Mechanics and Materials 193-194 (August 2012): 949–53. http://dx.doi.org/10.4028/www.scientific.net/amm.193-194.949.
Full textAbstract:
In this paper, according to the characteristics of near-fault earthquakes, combined with the strong ground motion attenuation law in China, the nonstationary power spectrum of bidirectional ground motion input is obtained through random vibration analysis. By introducing the pseudo excitation algorithm, the evolutionary power spectral density (PSD) of acceleration at the engineering bedrock is handled as the nonstationary pseudo input, and the Hardin-Drnevich hyperbolic model is utilized to take into account the nonlinearity of soil layer. On this basis, finite element method in the time domain and frequency domain are used for seismic response analysis of soil profile. Values including various time-varying power spectral density of the dynamic response, time varying RMS and time-dependent reliability at different threshold can be obtained by calculating, which provides a basis for the analysis of the foundation dynamic reliability assessment.
44
K, Anju, Anitha Jegadeeshwari L, and Nagendra Gandhi N. "OPTIMIZATION OF GREEN SYNTHESIZED SILVER NANOPARTICLES FROM CARALLUMA UMBELLATA." International Journal of Applied Pharmaceutics 10, no. 4 (2018): 103. http://dx.doi.org/10.22159/ijap.2018v10i4.26928.
Full textAbstract:
Objective: The current study focuses on optimization and ecologically innocuous green synthesis of silver nanoparticles (AgNPs) using tribal plant Caralluma umbellata and to study its potential as an antibacterial and antifungal agent.Methods: The synthesis of AgNPs were confirmed by the colour change of the stem extract from yellow to dark brown and by UV-Visible spectroscopy. The optimum conditions for synthesis of AgNPs were analysed using Response surface methodology (RSM) based Box-Behnken design (BBD) using Design Expert software (7.0.0 trial version). The AgNPs synthesized were characterized by Scanning electron microscope (SEM), Energy dispersive X-ray (EDX), Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analysis. Further, antibacterial and antifungal activity were performed using well diffusion method for both plant extract and AgNPs.Results: The UV-Visible spectrum of AgNPs revealed characteristic peak at 425.5 nm. The crystalline nature of synthesized AgNPs was confirmed by XRD with average size 26 nm. SEM confirms the spherical shape of AgNPs and by EDX the presence of elemental silver was observed. The ability of the plant to produce both reducing and capping agents were confirmed by FTIR. The optimum conditions for synthesis of AgNPs were found to be 0.55 mmol AgNO3 concentration, 45 °C temperature and 24h reaction time. Both plant sample and synthesized AgNPs exhibited good antimicrobial activity where AgNPs showed superior efficacy as an antimicrobial agent over the other.Conclusion: From the results obtained, it can be deduced that both C. umbellata stem extract and synthesized AgNPs can act as potent antimicrobial agent. But the synthesized AgNPs is more potent against bacteria and fungus.
45
Jordan, Bianca, Naiefa Rashied, and Marius Venter. "Rethinking Local Economic Development for Fetal Alcohol Spectrum Disorder in Renosterberg Local Municipality, South Africa." International Journal of Environmental Research and Public Health 20, no. 5 (2023): 4492. http://dx.doi.org/10.3390/ijerph20054492.
Full textAbstract:
Two towns in Renosterberg Local Municipality (RLM) in the Northern Cape Province of South Africa, Petrusville and Philipstown, have high Fetal Alcohol Spectrum Disorder (FASD) prevalence rates. FASD is linked to poverty and imposes high national economic costs. Thus, it is critical to understand the local economic development (LED) strategies used to mitigate the high prevalence of FASD. Moreover, there is sparse literature examining adult communities where FASD children reside. Understanding these adult communities is important because FASD cannot exist without adult gestational exposure to alcohol consumption. Using a mixed-method approach, this study uses a six-phase analytic approach to investigate the drinking culture and drinking motives in RLM, applied to two cross-sectional in-depth community needs assessments, five in-depth interviews, and three focus groups. This study also evaluates how the RLM targets FASD, as well as binge and risky drinking, in its municipal economic strategy by analysing its Integrated Development Plan (IDP) with respect to an eight-stage policy development process. The results indicate that 57% of respondents expressed concern regarding the unhealthy drinking culture in RLM, 40% felt that the residents of RLM drank in response to unemployment-related hopelessness, and 52% attributed the drinking culture to a lack of hobbies and recreational opportunities. The results of an analysis of the RLM IDP through the lens of Ryder’s eight-stage policy development process suggest that the decisive policy development process is not open to the public and that, furthermore, FASD is neglected. A dedicated alcohol consumption census-style study is recommended to broadly capture alcohol consumption in RLM, allowing researchers to identify the exact alcohol consumption patterns and priority areas for the IDP and public health policy. RLM should directly publicise its policy development process so that its IDP is inclusively formulated to address FASD, risky drinking, binge drinking, and gestational alcohol consumption.
46
Wang, Li-Jun, and Zhi-Wei Wang. "FEM verification of accelerated vibration test method based on Grms - T curve." Advances in Mechanical Engineering 14, no. 2 (2022): 168781322210784. http://dx.doi.org/10.1177/16878132221078487.
Full textAbstract:
Accelerated random vibration test is now the important dynamic performance and safety evaluation technique for transport packaging system during transportation. The current widely used time scale of accelerated random vibration test in engineering test and some standards is “Inverse power law,” which is based on Basquin (power function) fatigue damage model and [Formula: see text] curve, but is not completely suitable for transport packaging system. In author’s previous research, the general theory of accelerated random vibration test based on acceleration PSD and [Formula: see text] curve was developed which is applied for any fatigue damage model besides Basquin type. The study in this paper is the further and extensive research of previous research. The definite expression between response von Mises equivalent stress ([Formula: see text]) of the products and tri-axial acceleration Root-Mean-Square (RMS) was developed, based on which [Formula: see text] curve was transformed to [Formula: see text] curve to describe the product damage. Time scale of accelerated random vibration was obtained. The proposed method was verified by finite element analysis. In addition, the effects of excitation spectrum shape and system damping on the response vibration of products were discussed. This study is valuable in engineering for safety assessment and random vibration analysis of transport packaging system.
47
Wang, Zhi-Wei, and Li-Jun Wang. "On accelerated random vibration testing of product based on component acceleration RMS–life curve." Journal of Vibration and Control 24, no. 15 (2017): 3384–99. http://dx.doi.org/10.1177/1077546317705555.
Full textAbstract:
Accelerated random vibration testing is usually used to certify a product in random vibration environments. The current certification method is based on the inverse power law and is strictly valid only for Basquin’s type of damage and fatigue of materials. Based on the response spectrum analysis of the product in “the simply scaled accelerated vibrations” and taking the size of acceleration power spectral densities (PSD) the component is undergoing as an index to characterize and compare the damage of the component in different experiments, this paper develops a more practical method in engineering for accelerated random vibration testing of the product in the framework of linear random vibration theory and the rule of acceleration root mean square (RMS)–life curve of the component. The suggested method shows that the time scale is determined by the zero-th and second-order response acceleration spectral moments of the component in real vibration and that simulated in the laboratory, which demonstrates its potential value and advantage in practical application when compared with that based on the von Mises equivalent stress. Simplifications of the method are discussed in detail. In “the simply scaled accelerated vibrations”, the time scale is determined by the acceleration root mean square of the component in real or simulated vibration. It is coincident with the form reported by Allegri but having different physical significance in the case of Basquin’s type of damage and fatigue of the component. The validation experiment with a desk computer was carried out, leading to the verification of the present method.
48
Sha, Yun Dong, Hao Yuan Wang, and Huan Yu. "Nonlinear Response of Carbon-Carbon Laminated Panels to Random Acoustic Excitation under a Gradient Temperature Field." Applied Mechanics and Materials 696 (November 2014): 23–29. http://dx.doi.org/10.4028/www.scientific.net/amm.696.23.
Full textAbstract:
Future missions for aircraft will expose structures to severe thermal and acoustic loads. Efficient analysis methods for predicting nonlinear random response and fatigue life are urgently important. This paper presents a finite element model for analyzing nonlinear random dynamic behaviors of Carbon-Carbon composite panels under temperature gradients and Guassian excitations. The temperature distribution over the plate follows double sine curve. A finite element formulation combined with the equivalent linearization approach and normal mode method is established. The global system of equations is reduced to a set of nonlinear, coupled modal equations. Examples are given for an orthotropic C/C composite laminated panel at various combinations of temperatures gradients and sound pressure levels. Numerical results include RMS values of maximum deflection, time histories of deflection response and stress response, power spectrum densities, probability distribution functions and higher statistical moments. Numerical results verified all three types of panel motions for a simply supported orthotropic laminated plate: small-deflection random vibration about the initial equilibrium positions, snap-through motions between the two buckled positions, and nonlinear random response about new equilibrium positions after post-buckling. Numerical results will provide the important reference basis to aero engine structural integrity design and improving the structure dynamic strength and working life.
49
Li, Meng, and Yong Zhang. "Convergence Optimization and Verification for Single-Channel Remote Parameter Control of a Nonlinear System." Applied Sciences 9, no. 3 (2019): 549. http://dx.doi.org/10.3390/app9030549.
Full textAbstract:
In this paper, the theory of RPC (remote parameter control) iteration process of linear situation without and with iteration coefficient as well as nonlinear situation with coefficient is analyzed. The influence of iteration coefficient on iterative convergence control condition is analyzed. Two kinds of optimized control method for iteration coefficient based on the system transfer function estimation are proposed. A lightweight motorcycle and electro-hydraulic servo road vibration test bench are used to verify the feasibility of the optimized control methods for the reproduction of road profiles of SISO (single-input, single-output) system. According to the experiment result, which is the RMS (root mean square) of the NSRE (normalized spectrum of response error) of system, the convergent precision, convergent speed and iteration stability are discussed to present the advantage and disadvantage of the optimized control methods. Compared with three commonly used manual methods, the result shows the rapidity and stability of optimized control methods.
50
Webb, David J. "David Edgar Cartwright. 21 October 1926 — 2 December 2015." Biographical Memoirs of Fellows of the Royal Society 63 (January 2017): 99–115. http://dx.doi.org/10.1098/rsbm.2017.0001.
Full textAbstract:
David Cartwright was one of the world's leading authorities on the tides. However, when reflecting on his life, Cartwright made the point that his early scientific career was not a success. Indeed in 1953, at the age of 27, he had virtually despaired of any creative scientific future. At the time he was being pressurized to stop his work on the statistics of ship motions but his prospects rapidly changed when he was invited to apply for a post at the new National Institute of Oceanography (NIO) being set up by George Deacon. At NIO he soon made important contributions to the study of ocean waves, especially the calculation of directional spectrum and wave climate. His earlier involvement with ship motions also culminated in a successful joint study with Louis Rydill on the response of ships to the spectrum of waves. Following this, his use of computer methods for time-series analysis led to an invitation to the Scripps Institution of Oceanography where, with Walter Munk, he developed the response method of analysing tides making use of the very long tidal records collected from Hawaii and Newlyn. He was also made aware of the significant lack of good tidal data from the deep ocean. Returning to the UK, he continued these interests, studying the deep-ocean tides of the Atlantic and leading an international collaboration that measured deep-ocean tides. He also investigated the effect of tides on storm surges around the UK. He became assistant director in charge of the Institute of Oceanographic Sciences (IOS) Bidston laboratory, where he continued these activities and started research on estimating the tides using data from the Seasat radar altimeter. After retirement he successfully extended this work with Richard Ray at the Goddard Space Flight Center. Using Geosat altimeter data they generated accurate global maps of the tides in a set of papers that Cartwright considered to be his best work. He wrote a successful book titled ‘ Tides: a scientific history ’, and later published further work with Ray on the internal tides of the ocean.