Existence and Decay of Solutions of a Nonlinear Viscoelastic Problem with a Mixed Nonhomogeneous Condition

We study the initial-boundary value problem for a nonlinear wave equation given by u_{tt}-u_{xx}+\int_{0}^{t}k(t-s)u_{xx}(s)ds+ u_{t}^{q-2}u_{t}=f(x,t,u) , 0 < x < 1, 0 < t < T, u_{x}(0,t)=u(0,t), u_{x}(1,t)+\eta u(1,t)=g(t), u(x,0)=\^u_{0}(x), u_{t}(x,0)={\^u}_{1}(x), where \eta \geq 0, q\geq 2 are given constants {\^u}_{0}, {\^u}_{1}, g, k, f are given functions. In part I under a certain local Lipschitzian condition on f, a global existence and uniqueness theorem is proved. The proof is based on the paper [10] associated to a contraction mapping theorem and standard arguments of density. In Part} 2, under more restrictive conditions it is proved that the solution u(t) and its derivative u_{x}(t) decay exponentially to 0 as t tends to infinity.Comment: 26 page

Large time behavior of differential equations with drifted periodic coefficients modeling Carbon storage in soil

This paper is concerned with the linear ODE in the form $y'(t)=\lambda\rho(t)y(t)+b(t)$, $\lambda <0$ which represents a simplified storage model of the carbon in the soil. In the first part, we show that, for a periodic function $\rho(t)$, a linear drift in the coefficient $b(t)$ involves a linear drift for the solution of this ODE. In the second part, we extend the previous results to a classical heat non-homogeneous equation. The connection with an analytic semi-group associated to the ODE equation is considered in the third part. Numerical examples are given.Comment: 18 page

YẾU TỐ ẢNH HƯỞNG ĐẾN SINH KẾ HỘ NGƯ NGHIỆP Ở HUYỆN QUẢNG ĐIỀN TỈNH THỪA THIÊN HUẾ

This study aims to determine the factors affecting the livelihood of fishing households in Quang Dien district, Thua Thien Hue Province. Data are collected from the survey of 150 fishing households in Quang Ngan and Quang Cong communes, Quang Dien district. Multiple regression model was used to analyze the factors affecting the household’s livelihood outcome.  The estimation results showed that, there were 6 factors positively impacting on the household’s livelihood outcome including the educational level of household heads, experiences, number of household’ labor, total farmland area, participation in unions and associations, and household’s livelihood strategies. Therefore, the policy implications have been proposed to improve household’s livelihood sustainability in the coming year.Nghiên cứu này nhằm xác định các yếu tố ảnh hưởng đến sinh kế của hộ ngư nghiệp tại huyện Quảng Điền, tỉnh Thừa Thiên Huế. Số liệu của nghiên cứu được thu thập thông qua khảo sát 150 hộ ngư nghiệp tại hai xã Quảng Ngạn và Quảng Công, huyện Quảng Điền. Phương pháp phân tích hồi quy đa biến được sử dụng để xem xét các yếu tố ảnh hưởng đến sinh kế của hộ. Kết quả ước lượng cho thấy, trong 9 yếu tố đưa vào mô hình, có 6 yếu tố có ảnh hưởng tích cực đến sinh kế của hộ, bao gồm: trình độ văn hóa của chủ hộ, kinh nghiệm sản xuất, số lao động, diện tích sản xuất, tham gia vào các tổ chức tại địa phương và chiến lược sinh kế. Từ đó, một số khuyến nghị được đề xuất nhằm giúp các hộ ngư nghiệp phát triển sinh kế bền vững trong thời gian tới

Correlation between Resilient Modulus MR and Deviator Stress for Subgrade soils of northern provinces in Vietnam

Recently, Resilient Modulus is applied in pavement structural design in Vietnam. The resilient modulus of subgrade soil is an essential input parameter for a flexible pavement design. The resilient modulus depends on soil properties, stress state, and soil type.  However, there is limited research on resilient modulus of soils and models to estimate resilient modulus in Vietnam. Therefore, in this study, soil samples were collected from two provinces in northern Vietnam, namely Bac Giang province and Ninh Binh province, and then physical and mechanical tests were conducted for these samples. In addition, a series of cyclic triaxial tests also conducted according to AASHTO T307 specification to obtain resilient modulus of these soils.  The results showed that the resilient modulus decreased with the increase of deviator stress for Bac Giang samples and increased with the increase of deviator stress in the case of Ninh Binh samples. Simple deviator stress models have developed to estimate a resilient modulus of soils in the area

Correlation between Resilient Modulus MR and Deviator Stress for Subgrade soils of northern provinces in Vietnam

Recently, Resilient Modulus is applied in pavement structural design in Vietnam. The resilient modulus of subgrade soil is an essential input parameter for a flexible pavement design. The resilient modulus depends on soil properties, stress state, and soil type.  However, there is limited research on resilient modulus of soils and models to estimate resilient modulus in Vietnam. Therefore, in this study, soil samples were collected from two provinces in northern Vietnam, namely Bac Giang province and Ninh Binh province, and then physical and mechanical tests were conducted for these samples. In addition, a series of cyclic triaxial tests also conducted according to AASHTO T307 specification to obtain resilient modulus of these soils.  The results showed that the resilient modulus decreased with the increase of deviator stress for Bac Giang samples and increased with the increase of deviator stress in the case of Ninh Binh samples. Simple deviator stress models have developed to estimate a resilient modulus of soils in the area

The regularity and exponential decay of solution for a linear wave equation associated with two-point boundary conditions

This paper is concerned with the existence and the regularity of global solutions to the linear wave equation associated with two-point type boundary conditions. We also investigate the decay properties of the global solutions to this problem by the construction of a suitable Lyapunov functional.Comment: 18 page

Existence, blow-up and exponential decay estimates for a nonlinear wave equation with boundary conditions of two-point type

This paper is devoted to study a nonlinear wave equation with boundary conditions of two-point type. First, we state two local existence theorems and under suitable conditions, we prove that any weak solutions with negative initial energy will blow up in finite time. Next, we give a sufficient condition to guarantee the global existence and exponential decay of weak solutions. Finally, we present numerical resultsComment: 2

DEVELOPMENT AND EVALUATION OF ORAL SUSTAINED-RELEASE RANITIDINE DELIVERY SYSTEM BASED ON BACTERIAL NANOCELLULOSE MATERIAL PRODUCED BY KOMAGATAEIBACTER XYLINUS

Objective: The short biological half-life (2-3 h) and low bioavailability (50 %) of ranitidine (RAN) following oral administration favor the development of a controlled release system. This study was aimed to develop and in vitro evaluate oral sustained-release RAN delivery system based on the bacterial nanocellulose material (BNM) produced by Komagataeibacter xylinus (K. xylinus) from selected culture media. Methods: BNMs are biosynthesized by K. xylinus in the standard medium (SM) and coconut water (CW). RAN was loaded in BNMs by the absorption method. The structural and physicochemical properties of BNMs and BNMs-RAN were evaluated via swelling behavior, FTIR, and FESEM techniques. Moreover, the effect of BNMs on RAN release profile and release kinetics was analyzed and evaluated. Results: The amount of loaded RAN or entrapment efficacy for BNM-CW is higher than for BNM-SM. The BNM-SM-RAN and BNM-CW-RAN exhibited a decreased initial burst release system followed by a prolonged RAN release up to 24 h in relation to the commercial tablets containing RAN. The RAN release from these formulations was found higher in the SGF medium than that of in SIF medium. RAN released from these formulations was found to follow the Korsmeyer-Peppas model and diffusion sustained drug release mechanism. The sustained release of RAN from BNM-SM-RAN was slower than for RAN from BNM-CW-RAN, but the mechanism of sustained RAN release was the same. Conclusion: Oral sustained-release RAN delivery system based on BNMs was successfully prepared and evaluated for various in vitro parameters. The biopolymers like BNM-SM and BNM-CW could be utilized to develop oral sustained RAN release dosage form