Compaction Conditions Research Articles

Approximating Common Solution of Minimization Problems Involving Asymptotically Quasi-Nonexpansive Multivalued Mappings

In this paper, an iterative scheme for finding common solutions of the set of fixed points for a pair of asymptotically quasi-nonexpansive mapping and the set of minimizers for the minimization problem is constructed. Using the idea of the jointly demicloseness principle, strong convergence results are achieved without imposing any compactness condition on the space or the operator. Our results improve, extend and generalize many important results in the literature.

Parameter Estimation in Adaptive Control of Time-Varying Systems Under a Range of Excitation Conditions

This article presents a new parameter estimation algorithm for the adaptive control of a class of time-varying plants. The main feature of this algorithm is a matrix of time-varying learning rates, which enables parameter estimation error trajectories to tend exponentially fast toward a compact set whenever excitation conditions are satisfied. This algorithm is employed in a large class of problems where unknown parameters are present and are time-varying. It is shown that this algorithm guarantees global boundedness of the state and parameter errors of the system, and avoids an often used filtering approach for constructing key regressor signals. In addition, intervals of time over which these errors tend exponentially fast toward a compact set are provided, both in the presence of finite and persistent excitation. A projection operator is used to ensure the boundedness of the learning rate matrix, as compared to a time-varying forgetting factor. Numerical simulations are provided to complement the theoretical analysis.

Evaluation of the performance of a drainage geocomposite in a simple cover system based on 10 year measurements

In the course of the geotechnical investigations for a new runway at Munich Airport the hydro-mechanical behaviour of organogenic clays was studied. With the aim of an efficient use of materials the organogenic clay shall be used for noise and view barriers. As the organogenic clays have increased arsenic contents the percolation of such structures should be minimized. For the detailed investigation of the hydro-mechanical behaviour and for the determination of seepage quantities, a large scale, 5 m high, 30 m long and 25 m wide test fill was constructed. Due to the low permeability of the organogenic clays in compacted condition a cover design with a drainage mat and a top layer without an additional sealing layer was chosen. Measurements of the water balance were collected since the installation in 2008. The results show very low leachate quantities, although humid climatic conditions with average annual precipitation of approx. 745 mm were present. The low leachate rates can be mainly attributed to the capillary-breaking effect of the drainage geocomposite and the high water retention capacity of the topsoil. Based on the results the presented simple cover system can be considered an efficient and effective solution for minimizing infiltration water into core materials of embankments and noise barriers in road-way design.

Exploring Conditions for Handling Packing and Shipping Aedes aegypti Males to Support an SIT Field Project in Brazil.

Simple SummaryAedes-transmitted diseases are one of the most burdensome problems for public health worldwide. These diseases can be controlled by reducing the vector population, which can use alternative methods by releasing sterile male mosquitoes. Here, we show the impact of chilling, compacting, and transporting procedures on male quality. Our results reveal the temperature required for the absolute knockout of the Aedes males from a local strain. We recorded an adverse effect of chilling on the escape rate; however, after 24 h of recovery, we did not detect it. The interaction between density and transportation time impacted the survival, insemination, and flight ability rates. These outcomes are essential to developing Aedes packing and shipping protocols for the mosquito sterile release technique.The sterile insect technique (SIT) application, as an alternative tool for conventional mosquito control methods, has recently gained prominence. Nevertheless, some SIT components require further development, such as protocols under large-scale conditions, focusing on packing and shipping mosquitoes, and considering transporting time. Immobilization of Aedes aegypti males was tested at temperatures 4, 7, 10, and 14 °C, and each temperature was assessed for 60, 90, and 120 min. The recovery after 24 h was also studied. Chilled and control-reared males had comparable survival rates for all conditions, although 4 °C for 120 min impacted male survival. The male escape rate was affected after 60 min of exposure at 4 °C; this difference was not significant, with 24 h of recovery. First, we defined the successful immobilization at 4 °C for 60 min, thus enabling the evaluation of two transportation intervals: 6 and 24 h, with the assessment of different compaction densities of 100 and 150 mosquitoes/cm3 at 10 °C to optimize the shipment. Compaction during simulated mosquito shipments reduced survival rates significantly after 6 and 24 h. In the mating propensity and insemination experiments, the sterile males managed to inseminate 40 to 66% for all treatments in laboratory conditions. The male insemination propensity was affected only by the highest compaction condition concerning the control. The analysis of the densities (100 and 150 males/cm3) showed that a higher density combined with an extended shipment period (24 h) negatively impacted the percentage of inseminated females. The results are very helpful in developing and improving the SIT packing and shipment protocols. Further studies are required to evaluate all combined parameters’ synergetic effects that can combine irradiation to assess sexual competitiveness when sterile males are released into the field.

Attractors for the inhomogeneous incompressible Navier–Stokes flows

This paper is devoted to the evolution of Lions’s weak solutions to the inhomogeneous Navier–Stokes equations. After proving that the kinetic energy is eventually bounded, we obtain a weakly compact global attractor that all Lions’s weak solutions approach as time tends to infinity. Furthermore, the existence of attracting sets in strong topology is established for short trajectories satisfying an additional compactness condition on the density.

USING THE MEASURE OF NONCOMPACTNESS TO STUDY A NONLINEAR IMPULSIVE CAUCHY PROBLEM WITH TWO DIFFERENT KINDS OF DELAY

We apply the noncompactness measure by Mawhin to establish sufficient conditions for the existence and uniqueness (EU) of solution to a nonlinear Cauchy problem. The aforesaid problem is investigated under impulsive and nonlinear integral boundary conditions. Further, the problem under consideration contains Caputo-type fractional-order derivative while two different kinds of delay are also involved. After establishing the existence results, we derive some adequate results for the stability analysis of Hyers–Ulam (HU) type. Here, it should be kept in mind that the proposed tools can reduce the strong compact condition by weaker compactness. For justification, we provide some examples also.

A Modified Proximal Point Algorithm for Finite Families of Minimization Problems and Fixed Point Problems of Asymptotically Quasi-nonexpansive Multivalued Mappings

ln this paper, a new iterative algorithm for finding common ele-ments of the set of fixed points for a finite family of asymptotically quasi-nonexpansive multivalued mappings and the set of minimizers for a finite family of minimization problem is constructed. Under mild conditions on the control sequences, strong convergence of our algorithm was achieved without necessarily imposing any compactness condition on the space or the operator by using an independent approach. Our results improve, ex-tend and generalize many important results recently announced in current literature.

Research into compaction characteristics of large-size coarse-grained soil and application

The filling characteristic of rockfill is a non-ignorable engineering problem for high dams, and a reasonable control of compaction quality is the key to promoting the development of high dams. In this article, numerical and field tests were implemented to study the main problems affecting the compaction characteristics of large-size coarse-grained soil, namely determinations of the reasonable H0/dmax (the ratio of the compaction layer thickness to the maximum particle size) and the main influencing factors of minimum porosity. The macroscopic manifestations of the compaction characteristics were analyzed from the perspectives of energy, force chain, and particle breakage. The interaction between particles was explained by the ‘filling effect’ of fine particles, the ‘wedging effect’, and the ‘wall effect’ of coarse particles. It was found that the minimum porosity was not an inherent characteristic of rockfill, since the porosity and the corresponding degree of breakage were influenced by the compaction conditions. The value of H0/dmax meeting engineering practice was proposed, which can create favorable compaction conditions for obtaining the minimum porosity. Meantime, some suggestions were provided for obtaining the minimum porosity of large-size coarse-grained soil. The research results have an application reference value for the filling design and evaluation of high dams.

ADER scheme for incompressible Navier-Stokes equations on overset grids with a compact transmission condition

A space-time Finite Volume method is devised to simulate incompressible viscous flows in an evolving domain. Inspired by the ADER method (based on a Finite-Element-prediction/Finite-Volume-correction approach), the Navier-Stokes equations are discretized onto a space-time overset grid which is able to take into account both the shape of a possibly moving object and the evolution of the domain. A compact transmission condition is employed in order to mutually exchange information from one mesh to the other. The resulting method is second order accurate in space and time for both velocity and pressure. The accuracy and efficiency of the method are tested through reference simulations.

Higher Topological Type Semiclassical States for Sobolev Critical Dirac Equations with Degenerate Potential

In this paper, we are concerned with semiclassical states to the following Sobolev critical Dirac equation with degenerate potential, $$-\text {i} \epsilon \alpha \cdot \nabla u + a \beta u + V(x) u=|u|^{q-2} u + |u| u \quad \text{ in } \,\, \mathbb {R}^3, $$ where $$u:\mathbb {R}^3\rightarrow \mathbb {C}^4$$ , $$2<q<3$$ , $$\epsilon >0$$ is a small parameter, $$a>0$$ is a constant, $$\alpha =(\alpha _1, \alpha _2, \alpha _3)$$ , $$\alpha _j$$ and $$\beta $$ are $$4 \times 4$$ Pauli–Dirac matrices. We construct an infinite sequence of higher topological type semiclassical states with higher energies concentrating around the local minimum points of the degenerate potential V. Here the degeneracy of V means that $$|V(x)|<a$$ for any $$x \in \mathbb {R}^3$$ and |V(x)| may approach a as |x| tends to infinity. The solutions are obtained from a minimax characterization of higher dimensional symmetric linking structure, which correspond to critical points of the underlying energy functional at energy levels where compactness condition breaks down. Our approach is variational, which mainly relies on penalization method and blow-up arguments along with local type Pohozaev identity.

Conditions for compactness of integral operator on Musielak--Orlicz space of vector-valued functions

Conditions for compactness of integral operator on Musielak--Orlicz space of vector-valued functions

Degenerate Fractional Kirchhoff-Type System with Magnetic Fields and Upper Critical Growth

This paper deals with the following degenerate fractional Kirchhoff-type system with magnetic fields and critical growth: $$\begin{aligned} \left\{ \begin{array}{lll} -\mathfrak {M}(\Vert u\Vert _{s,A}^2)[(-\Delta )^s_Au+u] = G_u(|x|,|u|^2,|v|^2) \\ \quad +\left( \mathcal {I}_\mu *|u|^{p^*}\right) |u|^{p^*-2}u \ &{}\text{ in }\,\,\mathbb {R}^N,\\ \mathfrak {M}(\Vert v\Vert _{s,A})[(-\Delta )^s_Av+v] = G_v(|x|,|u|^2,|v|^2) \\ \quad +\left( \mathcal {I}_\mu *|v|^{p^*}\right) |v|^{p^*-2}v \ &{}\text{ in }\,\,\mathbb {R}^N, \end{array}\right. \end{aligned}$$where $$\begin{aligned}\Vert u\Vert _{s,A}=\left( \iint _{\mathbb {R}^{2N}}\frac{|u(x)-e^{i(x-y)\cdot A(\frac{x+y}{2})}u(y)|^2}{|x-y|^{N+2s}}{\text {d}}x {\text {d}}y+\int _{\mathbb {R}^N}|u|^2{\text {d}}x\right) ^{1/2},\end{aligned}$$and \((-\Delta )_{A}^s\) and A are called magnetic operator and magnetic potential, respectively, \(\mathfrak {M}:\mathbb {R}^{+}_{0}\rightarrow \mathbb {R}^{+}_0\) is a continuous Kirchhoff function, \(\mathcal {I}_\mu (x) = |x|^{N-\mu }\) with \(0<\mu <N\), \(C^1\)-function G satisfies some suitable conditions, and \(p^* =\frac{N+\mu }{N-2s}\). We prove the multiplicity results for this problem using the limit index theory. The novelty of our work is the appearance of convolution terms and critical nonlinearities. To overcome the difficulty caused by degenerate Kirchhoff function and critical nonlinearity, we introduce several analytical tools and the fractional version concentration-compactness principles which are useful tools for proving the compactness condition.

Impact of compaction ratio and loading period on compressional behavior of foam glass aggregates

Foam glass aggregates are used as a lightweight material in various civil engineering applications due to their big granular nature. Investigating the impact of compaction ratio, loading period, and environmental condition on the compressional behavior of the material is highly appreciated. In this study, after examining the pore microstructure and elements of the material, a series of static compression loads starting from 50 kPa to 300 kPa with 50 kPa intervals were applied on foam glass aggregate samples which were prepared with four different compaction ratios (10%, 20%, 30%, and 40%). The density and porosity of the material at different compaction ratios were also tested. The results showed a significant decrease in vertical strain values, from 6.2% at 10% compaction to 0.8% at 40% compaction. The compressibility rate significantly reduced, especially after 20% compaction. Calculated Eoed ranged between 7.9 MPa at 10% compaction under 50 kPa loading to 23 MPa at 40% compaction under 300 kPa loading. The long-term loading stage revealed that the material's strain values are not significantly time-dependent, especially when the material has been compacted more than 20%. The porosity of the samples was only reduced by 3% after compacting the aggregate to a 40% ratio. The influence of submergence on the compressional behavior of foam glass aggregate for the given loading range was eliminated when the material was compacted by more than 20%.

Evaluation of long-term strength and durability performance of cementitious composites with low polypropylene fiber content and local river sand

This study aims to investigate the long-term mechanical properties and durability of cementitious composites (CC) with low polypropylene (PP) fiber content and local river sand. The CC samples were prepared with different water-to-binder (w/b) ratios (0.20, 0.25, and 0.3), low PP fiber content (0.6% by mass of binder), locally available river sand, and fly ash (FA) sourced in the Mekong Delta region, corresponding to the mixture name WB20, WB25, and WB30, respectively. Then, the mechanical properties were investigated through compressive and flexural strengths and ultrasonic pulse velocity tests, while durability was assessed via chloride ion penetration and sulfate resistance. The results revealed that the mixture with the w/b of 0.25 achieved the best performance in terms of both mechanical and durability performance due to the optimal conditions of compaction, mixing water content, and also the latent pozzolanic reaction of FA in the hydrated cementitious composites. Besides, the CC samples with 0.6% PP fiber exhibited ductility behavior under compression and flexure, characterizing that CC samples do not completely separate from each other when damaged due to the fiber bridging effect. Moreover, the CC samples obtained excellent long-term durability (up to 120 days old) in terms of sulfate attack and chloride resistance in the following order WB25 &gt; WB20 &gt; WB30. The results of this study confirm the applicability of the local materials for producing good quality and low-cost cementitious composites.

Structure evaluation of a tropical residual soil under wide range of compaction conditions

Soil compaction is one of the most common techniques used to engineer the soil. It is especially appealing to developing countries for its cost-effective and sustainable attributes for improving the soil's geotechnical characteristics. The compaction process along with the complexity of residual soils, abundant in the tropics zone, can have an impact on the performance of geotechnical structures built with these soils. Therefore, it is important to understand the influence that certain compaction conditions have on the structure of these materials. To investigate that, mercury intrusion porosimetry tests were performed on compacted samples of a tropical residual soil from Brazil under different conditions of water content and compactive effort. Results show that the compacted soil under all studied conditions presents a bimodal pore-size distribution (PSD). It appears that the low availability of water within the macro-pores, hence suction, could have played a decisive role in maintaining the bimodal framework of the PSD. In this respect, this study contributes to a better understanding of the tropical residual soils’ structure when subjected to different compaction conditions, thus providing means to improve field applications.

Compactness and fractal dimensions of inhomogeneous continuum random trees

We introduce a new stick-breaking construction for inhomogeneous continuum random trees. This new construction allows us to prove the necessary and sufficient condition for compactness conjectured by Aldous et al. (Probab Theory Relat Fields 129(2):182–218, 2004) by comparison with Lévy trees. We also compute the fractal dimensions (Minkowski, Packing, Hausdorff).

Landau quantization and spin polarization of cold magnetized quark matter * *Support from the National Natural Science Foundation of China (11875181, 11875052, 11947098, 12005005, 61973109), the Hunan Provincial Natural Science Foundation of China (2021JJ40188), the Scientific Research Fund of Hunan Provincial Education Department of China (19C0772), the Scientific Research Fund of Hunan University of Science and Technology (E52059), and the

The magnetic field and density behaviors of various thermodynamic quantities of strange quark matter under compact star conditions are investigated in the framework of the thermodynamically self-consistent quasiparticle model. For individual species, a larger number density leads to a larger magnetic field strength threshold that aligns all particles parallel or antiparallel to the magnetic field. Accordingly, in contrast to the finite baryon density effect which reduces the spin polarization of magnetized strange quark matter, the magnetic field effect leads to an enhancement of it. We also compute the sound velocity as a function of the baryon density and find the sound velocity shows an obvious oscillation with increasing density. Except for the oscillation, the sound velocity grows with increasing density, similar to the zero-magnetic field case, and approaches the conformal limit at high densities from below.

Toeplitz Operators on the Unit Ball with Locally Integrable Symbols

We study the boundedness of Toeplitz operators T_psi with locally integrable symbols on weighted harmonic Bergman spaces over the unit ball of {mathbb {R}}^n. Generalizing earlier results for analytic function spaces, we derive a general sufficient condition for the boundedness of T_psi in terms of suitable averages of its symbol. We also obtain a similar “vanishing” condition for compactness. Finally, we show how these results can be transferred to the setting of the standard weighted Bergman spaces of analytic functions.

Numerical analysis of cover systems for mining waste in tropical regions

ABSTRACT The flow of water in mining waste may cause serious environmental impacts associated with acid-rock drainage. In relatively dry climates, dry soil covers have been considered as feasible alternatives to minimise such effects. The objective of this paper is to evaluate the influence of the hydrological cycle and soil type on the performance of dry cover systems, considering the tropical conditions found in Brazil’s central-west region. Numerical analyzes of four different cover systems composed of tropical soils were performed using the Finite Element Method. Among the proposed arrangements, three use a soil that presents a bimodal soil-water characteristic curve and the fourth system employs a unimodal soil. The thicknesses of intermediate materials were varied and different representative precipitation parameters were considered for a period of one year. The results obtained were compared in terms of the internal flow and the capacity of the cover to store water. The results indicate that bimodal soils may not be ideal materials and require specific compaction conditions to reduce the volume of macropores. Unimodal tropical soils presented adequate response as store-and-release materials. The use of an intermediate layer acting as a capillary barrier did not offer significant improvement to the cover systems evaluated.

The structure of tropical lateritic soils as an impacting factor in the shape of soil-water characteristic curves

The presence of unsaturated flow in tropical lateritic soils of unknown hydromechanical behavior may lead to severe geotechnical problems. It is known that soil-water characteristic curves (SWCC) are a valuable tool to define this behavior and facilitate the suction estimation, acting on tests performed with no control of such parameter. This article aimed to determine and model the SWCC for 3 unprecedented tropical soils, in the undisturbed and the compacted conditions, from the Paraná state, located in the south of Brazil. The soils studied are one clay and two sands, all lateritic. The pressure plate and the filter paper methods were used to determine the SWCC. The samples were carved and submitted to the drying paths. Furthermore, Mercury Intrusion Porosimetry (MIP) tests were performed in samples of the studied soils in order to obtain the pore size distribution (PSD), contributing to the bimodal definition of curves and the prediction of SWCC main parameters. Both techniques (pressure plate and filter paper) were combined and the SWCC was adjusted by Gitirana &amp; Fredlund model, which efficiently represents the shape of the traditional curves for tropical soils. Furthermore, the SWCCs were predicted by PSD and obtained satisfactory numerical fits. All SWCC presented air entry values in the macropores that are characteristic of soils as the lateritic, given that its structure was considered a key factor in the shape of the curves.