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Fruit Yield and Quality, and Irrigation Water Use Efficiency of Summer Squash Drip-Irrigated with Different Irrigation Quantities in a Semi-Arid Agricultural Area

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Journal of Integrative Agriculture 2014年第11期13卷 2518-2526页

作者： Yasemin Kuslu Ustun Sahin Fatih M Kiziloglu Selcuk Memis department of Agricultural structures and Irrigation Atatürk University

Fruit yield, yield components, fruit mineral content, total phenolic content, antioxidant activity and irrigation water use efifciency （IWUE） of summer squash responses to different irrigation quantities were evaluated with a ifeld study. Irrigations were done when the total evaporated water from a Class A pan was about 30 mm. Different irrigation quantities were adjusted using three different plant-pan coefifcients （Kcp, 100% （Kcp1）, 85% （Kcp2） and 70% （Kcp3））. Results indicated that lower irrigation quantities provided statistically lower yield and yield components. The highest seasonal fruit yield （80.0 t ha-1） was determined in the Kcp1 treatment, which applied the highest volume of irrigation water （452.9 mm）. The highest early fruit yield, average fruit weight and fruit diameter, length and number per plant were also determined in the Kcp1 treatment, with values of 7.25 t ha-1, 264.1 g, 5.49 cm, 19.95 cm and 10.92, respectively. Although the IWUE value was the highest in the Kcp1 treatment （176.6 kg ha-1 mm-1）, it was statistically similar to the value for Kcp3 treatment （157.1 kg ha-1 mm-1）. Total phenolic content and antioxidant activity of fruits was higher in the Kcp1 （44.27 μg gallic acid equivalents （GAE） mg-1 fresh sample） and in the Kcp2 （84.75%） treatments, respectively. Major （Na, N, P, K, Ca, Mg and S） and trace （Fe, Cu, Mn, Zn and B） mineral contents of squash fruits were the highest in the Kcp2 treatment, with the exception of P, Ca and Cu. Mineral contents and total phenolic content were signiifcantly affected by irrigation quantities, but antioxidant activity was not affected. It can be concluded that the Kcp1 treatment was the most suitable for achieving higher yield and IWUE. However, the Kcp2 treatment will be the most suitable due to the high fruit quality and relatively high yield in water shortage conditions.

关键词： summer squash drip irrigation irrigation water use efifciency total phenolic content antioxidant activity fruit mineral content

Nonlinear integral resonant controller for vibration reduction in nonlinear systems

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Acta Mechanica Sinica 2016年第5期32卷 925-934页

作者： Ehsan Omidi S.Nima Mahmoodi Nonlinear Intelligent structures Laboratory Department of Mechanical Engineering The University of Alabama

A new nonlinear integral resonant controller（NIRC） is introduced in this paper to suppress vibration in nonlinear oscillatory smart structures. The NIRC consists of a first-order resonant integrator that provides additional damping in a closed-loop system response to reduce highamplitude nonlinear vibration around the fundamental resonance frequency. The method of multiple scales is used to obtain an approximate solution for the closed-loop *** closed-loop system stability is investigated using the resulting modulation equation. Finally, the effects of different control system parameters are illustrated and an approximate solution response is verified via numerical simulation *** advantages and disadvantages of the proposed controller are presented and extensively discussed in the results. The controlled system via the NIRC shows no high-amplitude peaks in the neighboring frequencies of the resonant mode,unlike conventional second-order compensation *** makes the NIRC controlled system robust to excitation frequency variations.

关键词： Active vibration control Cantilever Highamplitude oscillation Method of multiple scales Nonlinear vibration Piezoelectric actuator Smart structure

Deflection analysis of reinforced concrete beams strengthened with carbon fibre reinforced polymer under long-term load action

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第8期13卷 571-583页

作者： Mykolas DAUGEVIIUS Juozas VALIVONIS Gediminas MAR IUKAITIS department of Reinforced Concrete and Masonry structures Vilnius Gediminas Technical University

This paper presents the results of an experimental research on reinforced concrete beams strengthened with an external carbon fibre reinforced polymer(CFRP) layer under long-term load action that lasted for 330 *** describe the characteristics of deflection development of the beams strengthened with different additional anchorages of the external carbon fibre composite layer during the period of *** conducted experiments showed that the additional anchorage influences the slip of the external layer with respect to the strengthened ***,concrete and carbon fibre composite interface stiffness decreases with a long-term load ***,the proposed method of analysis based on the built-up-bars theory can be used to estimate concrete and carbon fibre composite interface stiffness in the case of long-term load.

关键词： Carbon fibre composite Beam strengthening Beam deflection Long-term load Bending stiffness Concrete and carbon fibre composite interface stiffness Effective inertia moment

MODELING OF FREE JUMPS DOWNSTREAM SYMMETRIC AND ASYMMETRIC EXPANSIONS:THEORITICAL ANALYSIS AND METHOD OF STOCHASTIC GRADIENT BOOSTING

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Journal of Hydrodynamics 2010年第1期22卷 110-120页

作者： MOHAMED A.Nassar Water and Water structures Engineering department Faculty of EngineeringZagazig University

The general computational approach of Stochastic Gradient Boosting （SGB） is seen as one of the most powerful methods in predictive data mining. Its applications include regression analysis, classification problems with/without continuous categorical predictors. The present theoretical and experimental study aims to model the free hydraulic jump created through rectangular Channels Downstream （DS） symmetric and asymmetric expansions using SGB. A theoretical model for prediction of the depth ratio of jumps is developed using the governing flow equations. At the same time, statistical models using linear regression are also developed. Three different parameters of the hydraulic jump are investigated experimentally using modified angled-guide walls. The results from the modified SGB model indicate a significant improvement on the original models. The present study shows the possibility of applying the modified SGB method in engineering designs and other practical applications.

关键词： Stochastic Gradient Boosting (SGB) free jump symmetric asymmetric theoretical regression experiment

Lyapunov stability of competitive cells dynamics in tumor mechanobiology

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Acta Mechanica Sinica 2021年第2期37卷 244-263页

作者： Angelo Rosario Carotenuto Arsenio Cutolo Stefania Palumbo Massimiliano Fraldi department of structures for Engineering and Architecture University of Napoli Federico IINapoliItaly

Poromechanics plays a key role in modelling hard and soft tissue behaviours,by providing a thermodynamic framework in which chemo-mechanical mutual interactions among fluid and solid constituents can be consistently rooted,at different scale *** this context,how different biological species(including cells,extra-cellular components and chemical metabolites)interplay within complex environments is studied for characterizing the mechanobiology of tumor growth,governed by intra-tumoral residual stresses that initiate mechanotransductive processes deregulating normal tissue homeostasis and leading to tissue *** the coupling between tumor poroelasticity and interspecific competitive dynamics has recently highlighted how microscopic cells and environment interactions influence growth-associated stresses and tumor pathophysiology,the nonlinear interlacing among biochemical factors and mechanics somehow hindered the possibility of gaining qualitative insights into cells *** by this,in the present work we recover the linear poroelasticity in order to benefit of a reduced complexity,so first deriving the well-known Lyapunov stability criterion from the thermodynamic dissipation principle and then analysing the stability of the mechanical competition among cells fighting for common space and resources during cancer growth and *** the end,the linear poroelastic model enriched by interspecific dynamics is also exploited to show how growth anisotropy can alter the stress field in spherical tumor masses,by thus indirectly affecting cell mechano-sensing.

关键词： Tumor growth Poroelasticity Cells competition Volterra-Lotka dynamics Stability

Influence of earthquake direction on the seismic response of irregular plan RC frame buildings

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Earthquake Engineering and Engineering Vibration 2014年第2期13卷 243-256页

作者： Magliulo G Maddaloni G Petrone C University of Naples Federico II Department of Structures for Engineering and Architecture University of Naples Parthenope Department of Engineering

The nonlinear response of structures is usually evaluated by considering two accelerograms acting simultaneously along the orthogonal directions. In this study, the infl uence of the earthquake direction on the seismic response of building structures is examined. Three multi-story RC buildings, representing a very common structural typology in Italy, are used as case studies for the evaluation. They are, respectively, a rectangular plan shape, an L plan shape and a rectangular plan shape with courtyard buildings. Nonlinear static and dynamic analyses are performed by considering different seismic levels, characterized by peak ground acceleration on stiff soil equal to 0.35 g, 0.25 g and 0.15 g. Nonlinear dynamic analyses are carried out by considering twelve different earthquake directions, and rotating the direction of both the orthogonal components by 30° for each analysis(from 0° to 330°). The survey is carried out on the L plan shape structure. The results show that the angle of the seismic input motion signifi cantly infl uences the response of RC structures; the critical seismic angle, i.e., the incidence angle that produces the maximum demand, provides an increase of up to 37% in terms of both roof displacements and plastic hinge rotations.

关键词： plan irregularity nonlinear analyses reinforced concrete buildings seismic performance ground motion directionality

Simulation Tools for a Fiber-Optic Based Structural Health Monitoring System

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第2期35卷 219-225页

作者： Alfredo Güemes Antonio Fernandez-Lopez Jaime García-Ramírez Maria Eugenia Reyes-Perez Flor Criado Zurita Laboratory for Composites & Smart structures Department of AeronauticsPolytechnic University of Madrid

Probability of detection(POD)graphics allow for a change from qualitative to quantitative assessment for every damage detection system,and as such it is a main request for conventional non-destructive testing(NDT)*** availability can greatly help towards the industrialization of the corresponding Structural health monitoring(SHM)*** having in mind that for SHM systems the sensors are at fixed positions,and the location of a potential damage would change its *** robust simulation tools are required to obtain the model assisted probability of detection(MAPOD)which is needed to validate the SHM *** tool may also help for the optimization of the sensor distribution,and finally will allow a probabilistic risk ***,simulation of ultrasonic waves SHM system,was a main milestone in this *** article deals with the simulation tools for a strain based SHM system,using fiber optic sensors(FOS).FOS are essentially strain/temperature sensors,either with multi-point or with distributed *** simulation tool includes the finite element model(FEM)for the original and damaged structure,and algorithms to compare the strain data at the pre-established sensors locations,and from this comparison to extract information about damage occurrence and *** study has been applied to the structure of an all-composite unmanned aircraft vehicle(UAV)now under construction,designed at Universidad Politecnica de Madrid for the inspection of electrical utilities *** sensing optical fibers were internally bonded at the fuselage and *** inspection is planned to be done with the aircraft at the test bench by imposing known *** the acquired strain data,damage occurrence may be calculated as slight deviations from the *** is a fast inspection procedure without requiring trained specialists,and it would allow for detection of hidden *** indicates that stringer par

关键词： damage detection fiber optics distributed sensing finite element models probability of detection(POD) principal component analysis (PCA) fibre bragg gratings (FBG)

Damage detection on framed structures: modal curvature evaluation using Stockwell Transform under seismic excitation

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Earthquake Engineering and Engineering Vibration 2015年第2期14卷 265-274页

作者： R.Ditommaso F.C.Ponzo G.Auletta department of structures Geotechnics Engineering Geology University of Basilicata School of Engineering University of Basilicata

The key parameters for damage detection and localization are eigenfrequencies, related equivalent viscous damping factors and mode shapes. The classical approach is based on the evaluation of these structural parameters before and after a seismic event, but by using a modern approach based on time-frequency transformations it is possible to quantify these parameters throughout the ground shaking phase. In particular with the use of the S-Transform, it is possible to follow the temporal evolution of the structural dynamics parameters before, during and after an earthquake. In this paper, a methodology for damage localization on framed structures subjected to strong motion earthquakes is proposed based on monitoring the modal curvature variation in the natural frequency of a structure. Two examples of application are described to illustrate the technique: Computer simulation of the nonlinear response of a model, and several laboratory(shaking table) tests performed at the University of Basilicata(Italy). Damage detected using the proposed approach and damage revealed via visual inspections in the tests are compared.

关键词： damage detection S-transform band-variable fi lter

Perforation studies of concrete panel under high velocity projectile impact based on an improved dynamic constitutive model

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Defence Technology（防务技术） 2023年第9期27卷 64-82页

作者： Fei Zhou Hao Wu Yuehua Cheng department of Disaster Mitigation for structures College of Civil EngineeringTongji UniversityShanghai200092China

The finite-depth concrete panels have been widely applied in the protective structures,and its impact resistance and dynamic fracture failures,especially the scabbing/perforation limits,under high velocity projectile impact,are mainly concerned by protective engineers,which are numerically studied based on an improved dynamic concrete model in this ***,based on the framework of the KCC(Karagozian&Case concrete)model,a dynamic concrete model is proposed which considers an independent tensile damage model and a continued transition between dynamic tensile and compressive ***,the strength surface,equation of state and damage parameters of the proposed model are comprehensively calibrated by a triaxial compressive test with high confinement pressure,the rationality of which is further verified based on the single element tests,e.g.,uniaxial and triaxial compression as well as uniaxial,biaxial and triaxial ***,a series of projectile high velocity impact tests on thin and thick concrete panels are simulated,which indicates that the projectile residual velocity and dynamic fracture failures are reproduced satisfactorily,while the KCC model underestimates both the spalling and scabbing dimensions ***,based on the validated concrete model and finite element analyses approach,the validations of the existing five empirical formulae are evaluated,in terms of the depth of penetration(DOP)and scabbing/perforation limits of concrete *** the Army corps of engineers(ACE)and modified National Defense Research Committee(NDRC)formulae are recommended in the design of the protective structure to avoid scabbing failure.

关键词： Concrete panel Projectile Dynamic fracture Scabbing limit Constitutive model