825 research outputs found
Three solutions for pertubed Dirichilet problem
\begin{abstract}
In this paper we prove the existence of at least three distinct solutions
to the following perturbed Dirichlet problem
\begin{displaymath}
\left\{
\begin{array}{ll}
-\Delta u= f(x,u)+\lambda g(x,u) & \mbox{in\ } \Omega\\
u=0 & \mbox{on\ } \partial \Omega,
\end{array}\right.
\end{displaymath}
where is an open bounded set with smooth
boundary and . Under very mild
conditions on and some assumptions on the behaviour of the potential
of at and , our result assures the existence of at least
three distinct solutions to the above problem for small enough.
Moreover such solutions belong to a ball of the space
centered in the origin and with radius not dependent on .
\end{abstract
Three periodic solutions for pertubed second order Hamiltonian system
Three periodic solutions for perturbed second order Hamiltonian systems
\begin{abstract}
In this paper we study the existence of three distinct solutions for the
following problem
\begin{displaymath}
\begin{array}{ll}
-\ddot{u}+A(t)u=\nabla F(t,u)+\lambda \nabla G(t,u) & \mbox{a.e\ in\ }
[0,T] \\
u(T)-u(0)=\dot{u}(T)-\dot{u}(0)=0,
\end{array}
\end{displaymath}
where , is a real positive number,
is a continuous
map from the interval to the set of -order symmetric matrices.
We propose sufficient conditions only on the potential . More
precisely, we assume that satisfies only a usual growth condition
which allows us to use a variational approach.
\end{abstract
Anaerobic Digestion of Olive Mill Wastewater in the Presence of Biochar
Biological treatments focused on stabilizing and detoxifying olive mill wastewater facilitate agronomic reuse for irrigation and fertilization. Anaerobic digestion is particularly attractive in view of energy recovery, but is severely hampered by the microbial toxicity of olive mill wastewater. In this work, the addition of biochar to the digestion mixture was studied to improve the stability and efficiency of the anaerobic process. Kinetics and yields of biogas production were evaluated in batch digestion tests with biochar concentrations ranging from 0 to 45 g L−1. The addition of biochar reduced sensibly the lag phase for methanogenesis and increased the maximum rate of biogas generation. Final yields of hydrogen and methane were not affected. Upon addition of biochar, soluble COD removal increased from 66% up to 84%, and phenolics removal increased from 50% up to 95%. Digestate phytotoxicity, as measured by seed germination tests, was reduced compared to raw wastewater. Addition of biochar further reduced phytotoxicity and, furthermore, a stimulatory effect was observed for a twenty-fold dilution. In conclusion, biochar addition enhances the anaerobic digestion of olive mill wastewaters by effectively reducing methanogenesis inhibition and digestate phytotoxicity, thus improving energy and biomass recovery
Electro-optical modulation at 1550 nm in an as-deposited hydrogenated amorphous silicon p-i-n waveguiding device.
Hydrogenated amorphous silicon (a-Si:H) has been already considered for the objective of passive optical elements, like waveguides and ring resonators, within photonic integrated circuits at λ = 1.55 μm. However the study of its electro-optical properties is still at an early stage, therefore this semiconductor in practice is not considered for light modulation as yet. We demonstrated, for the first time, effective electrooptical modulation in a reverse biased a-Si:H p-i-n waveguiding structure. In particular, phase modulation was studied in a waveguide integrated Fabry-Perot resonator in which the Vπ·Lπ product was determined to be 63 V·cm. Characteristic switch-on and switch-off times of 14 ns were measured. The device employed a wider gap amorphous silicon carbide (a-SiC:H) film for the lower cladding layer instead of silicon oxide. In this way the highest temperature involved in the fabrication process was 170°C, which ensured the desired technological compatibility with CMOS processes. © 2011 Optical Society of America
Unifying Foundation Models with Quadrotor Control for Visual Tracking Beyond Object Categories
Visual control enables quadrotors to adaptively navigate using real-time
sensory data, bridging perception with action. Yet, challenges persist,
including generalization across scenarios, maintaining reliability, and
ensuring real-time responsiveness. This paper introduces a perception framework
grounded in foundation models for universal object detection and tracking,
moving beyond specific training categories. Integral to our approach is a
multi-layered tracker integrated with the foundation detector, ensuring
continuous target visibility, even when faced with motion blur, abrupt light
shifts, and occlusions. Complementing this, we introduce a model-free
controller tailored for resilient quadrotor visual tracking. Our system
operates efficiently on limited hardware, relying solely on an onboard camera
and an inertial measurement unit. Through extensive validation in diverse
challenging indoor and outdoor environments, we demonstrate our system's
effectiveness and adaptability. In conclusion, our research represents a step
forward in quadrotor visual tracking, moving from task-specific methods to more
versatile and adaptable operations
The effects of kinematic condensation on internally resonant forced vibrations of shallow horizontal cables
This study aims at comparing non-linear modal interactions in shallow horizontal cables with kinematically non-condensed vs. condensed modeling, under simultaneous primary external and internal resonances. Planar 1:1 or 2:1 internal resonance is considered. The governing partial-differential equations of motion of non-condensed model account for spatio-temporal modification of dynamic tension, and explicitly capture non-linear coupling of longitudinal/ vertical displacements. On the contrary, in the condensed model, a single integro-differential equation is obtained by eliminating the longitudinal inertia according to a quasi-static cable stretching assumption, which entails spatially uniform dynamic tension. This model is largely considered in the literature. Based on a multi-modal discretization and a second-order multiple scales solution accounting for higher-order quadratic effects of a infinite number of modes, coupled/uncoupled dynamic responses and the associated stability are evaluated by means of frequency- and force-response diagrams. Direct numerical integrations confirm the occurrence of amplitude-steady or -modulated responses. Non-linear dynamic configurations and tensions are also examined. Depending on internal resonance condition, system elasto-geometric and control parameters, the condensed model may lead to significant quantitative and/or qualitative discrepancies, against the non-condensed model, in the evaluation of resonant dynamic responses, bifurcations and maximal/minimal stresses. Results of even shallow cables reveal meaningful drawbacks of the kinematic condensation and allow us to detect cases where the more accurate non-condensed model has to be used
Hydrogenated amorphous silicon multi-SOI waveguide modulator with low voltage-length product
n/
ANALOGUE OF DINI-RIEMANN THEOREM FOR NON-ABSOLUTELY CONVERGENT INTEGRALS
An analogue of classical Dini-Riemann theorem related to non-absolutelyconvergent series of real number is proved for the Lebesgue improper integral.An analogue of classical Dini-Riemann theorem related to non-absolutely convergent series of real number is proved for the Lebesgue improper integral
Henstock integral and Dini-Riemann theorem
In [5] an analogue of the classical Dini-Riemann theorem related to non-absolutely convergent series of real number is obtained for the Lebesgue improper integral. Here we are extending it to the case of the Henstock integral
synthesis characterization and applications of nano micro carbonaceous inerts a review
Abstract In recent years, a scientific shift has been observed towards the use of carbon based nano materials in different composites to enhance their mechanical and electrical properties. However, carbonaceous nano/micro inert particles synthesized through pyrolysis of agricultural and industrial wastes offer a very cost effective alternate to the commercially available carbon based materials such as carbon fibres, carbon nanotubes, graphene and graphene oxide. A comprehensive survey of reported data on the synthesis of carbon particles is presented in this article. The utilization of synthesized carbon particles as reinforcing material has also been explored together with an attempt of proposing future novel applications of synthesized carbon particles in cement based systems. In this paper, meticulous efforts have been made to overview the potential beneficial effects of synthesized carbon particles intrusions to cementitious systems for modifying/improving their mechanical characteristics
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