Search

Defective hydrated vanadium oxide embedded in porous carbon textile enables highly reversible Zn2+ to intercalate/deintercalate and fast charge transport, thereby promoting the pseudocapacitive behavior of zinc-ion batteries.

MXenes have been reported to have excellent electrical and thermal properties theoretically. However, the actual properties of the synthesized MXene are far less than expected. This discrepancy arises mostly from the structural defects formed during synthesis. This work demonstrates that the thermal, electrical, and mechanical properties of the Ti3C2 MXene can be readily improved via the vapor phase infiltration (VPI) phenomenon of platinum (Pt) which usually occurs in the conventional atomic layer deposition (ALD) process. The infiltrated Pt atoms are found to cure Ti-defects in the MXene and to build bridges that interconnect MXene nanoflakes by creating covalent Pt–C bonds, which act as highly efficient channels for electrical and thermal conduction. The Pt infiltrated MXene displays drastic enhancement in thermal, electrical, and mechanical properties, simultaneously. Notably, both in-plane electrical/thermal conductivity and cross-plane electrical/thermal conductivity are found to significantly increase (∼2.4/∼1.8 times and ∼6.6/∼5.0 times, respectively). Electrothermal heaters made by using the Pt-infiltrated MXene exhibit outstanding efficiency, high heating rate, and good stability.

The thermal properties of the polymer, together with mechanical stability, have been one of the key engineering factors to be considered for various applications. Here, we engineered the thermal conductivity of the amorphous poly(acrylic acid) (PAA) polymer by vapor-phase infiltration (VPI), which has usually occurred during the atomic layer deposition process. We observed that the VPI causes metal infiltration (e.g., Al and Zn) into the amorphous PAA polymer, which noticeably increases the thermal conductivity of the PAA polymer. From spectroscopy analysis and density functional theory simulations, we found that the carboxyl groups (-COOH) in PAA are notably modified and the bonding states of carbon and oxygen are significantly altered by the infiltrated metal. The newly formed Al-mediated bonds likely provide continuous phonon propagation pathways, thereby enhancing the thermal conductance. We believe that VPI could be a simple and useful way to engineer the thermal properties of various polymeric materials.

International audience; Damage in reinforced concrete structures is frequently caused by reinforcement corrosion due to carbonation. Although a wide range of literature contributed to the concrete carbonation consisting of experimental investigations and numerical simulations, research work on a complete numerical model for concrete carbonation prediction with integrated climatic variables (e.g., temperature, relative humidity) is still a challenge. The present paper aims to propose an advanced numerical model to simulate the penetration of carbon dioxide and moisture, diffusion of calcium ions, heat transfer, and porosity modification in concrete material using COMSOL Multiphysics software. Three coupled mass conservation equations of calcium, water, and carbon dioxide are solved together with additional equations regarding the heat transfer, variation of porosity, and content of portlandite and other hydrates and calcites. In this study, the actual temporal variabilities of temperature and relative humidity in Toulouse, France, are used as a case study. The predicted results of portlandite profiles and carbonation depth are compared with the experimental data and discussed to identify the effect of climatic variables on the concrete carbonation.

Currently, the river sand is becoming depletion leading to a rise in the price of construction material and issues related to the environment such as the depth of the river bed, lowering of the groundwater and salinity intrusion into the rivers. Meanwhile, demand for construction materials increases annually due to growth in infrastructure development demand. Therefore, finding alternative material sources is an urgent problem needing to be addressed. Specifically, sea sand has many potential abilities to replace river sand and other materials in construction. The result of the study revealed that sea sand on the coast of Vietnam accommodates most of the roadbed materials requirements according to standard TCVN 9436:2012. The study has proposed a feasible method to construct the roadbed by sea sand. The results of stability analysis by Slope/W show that the roadbed using alternating filling method considerably improves the safety factor which increases on average 13.8% in comparison with the roadbed is filled by sea sand and covered by clay. In addition, a cost comparison between the roadbed constructed by the alternating method and conventional roadbed shows that using sea sand brings a significant cost saving for the project. Moreover, using sea sand as an alternative material source also has several positive effects on the environment such as utilizing, dredging ports and seabed, making use of wild dunes, reducing the amount of river sand extracted annually, minimizing the impacts of river sand exploitation.

This study seeks to better understand the determinants of green building technology (GBT) adoption intention of construction developers in developing countries. In order to address these objectives, this study integrates the Diffusion of Innovation theory, the theory of Resource-based View, and the Resource Dependence Theory to analyze and construct the theoretical model of developers&rsquo, intentions to adopt GBTs from three perspectives, namely, technological, organizational, and environmental. The model was tested using survey data collected from 142 experienced managers in Vietnam. Data analysis was performed by SEM using the partial least squares (PLS) approach. The findings show that perceived GBT advantages, perceived GBT disadvantages, top management leadership, government support, project partners&rsquo, green building readiness, and social demand of green buildings are the significant factors that affect GBT adoption intention by developers. However, organizational GBT resource and GBT market readiness have no significant effect on developers&rsquo, GBT adoption intention. Theoretical and practical implications and limitations of the research are discussed, and suggestions for future research are also proposed.

Biodegradable polymers have been often used in place of conventional nondegradable polymers for industrial and medical applications. In particular, polylactide (PLA) has been regarded as a popular ecofriendly plastic and has many advantages like good biocompatibility and processability. Yet, it still has some drawbacks in mechanical properties. Here, we prepared Ti-infiltrated PLA by mimicking the gelatinous jaw of a seaworm whose mechanical properties are toggled up and down by the tiny amount of metal ions, expecting to prepare a new type of alternative. Ti induced significant chemical and microstructural changes in the PLA, which led to a notable improvement in the mechanical properties as compared to the neat PLA. The Ti-infiltrated PLA exhibited high resistance to rapid degradation. More importantly, the toxicity assessment demonstrated that the resulting PLA is still biocompatible and nontoxic. Consequently, we proved that the Ti-infiltrated PLA has high mechanical properties comparable to conventional nondegradable polymers and good biocompatibility as well as delayed biodegradability. We anticipate the current Ti-infiltrated PLA to be an ecofriendly replacement of some conventional plastics, which helps preserve a green environment.

Trước áp lực giao thông ngày càng tăng tại các đô thị lớn của Việt Nam, trong khi giao thông cá nhân khó có thể đáp ứng và gây ra nhiều hệ lụy về ùn tắc, tai nạn, ô nhiễm và bất bình đẳng, chính quyền đô thị đã và đang quan tâm đầu tư phát triển vận tải hành khách công cộng (VTKHCC), nhất là các loại hình có sức chở lớn.Trong quá trình biên soạn từ kết quả nghiên cứu và các nguồn tài liệu tham khảo, tác giả đã cố gắng giới thiệu những vấn đề cơ bản trong phát triển hạ tầng và tổ chức, quản lý giao thông công cộng hướng tới kết nối, bền vững. Tuy nhiên do đặc thù lĩnh vực giao thông công cộng rất rộng, có tính riêng biệt cao đối với mỗi công trình, nên nội dung cuốn sách có thể không thỏa mãn hoàn toàn các mong muốn của người đọc. Vì vậy, tác giả mong muốn nhận được các ý kiến đóng góp của bạn đọc để các lần tái bản sau sách được hoàn thiện hơn.Nhà xuất bản Xây dựng

Nuclear transparency is beneficial to nonproliferation. It helps non-nuclear-weapon states demonstrate their commitment to the nonproliferation regime and nuclear-weapon states account for their st...

Consider meromorphic functions f, g, and $$\alpha ,$$ where $$\alpha $$ is a small function with respect to f and g. Let Q be a polynomial of one variable. We give suitable conditions on the degree of Q and on the number of zeros and the multiplicities of the zeros of $$Q'$$ so as to be able to conclude uniqueness results if differential polynomials of the form $$(Q(f))^{(k)}$$ and $$(Q(g))^{(k)}$$ share $$\alpha $$ counting multiplicities. We do not assume that Q has a large order zero, nor do we place restrictions on the zeros and poles of $$\alpha .$$ Thus, our work improves on many prior results that either assume Q has a high order zero or place restrictions on the small function $$\alpha $$ .

The highway embankment construction allows to consume a huge volume of coal ash up to hundreds of thousands of tons per km. However, this is a material with very different physical and chemical properties from traditional materials, which requires different design, construction and acceptance solutions.

Street flooding in urban areas in Vietnam has always been a stress issue despite the municipal government’s investment in renovating and upgrading the drainage system. Until present, in order to evaluate and classify street flooding spots, the authorities have been applying the criteria specified in Document No. 338/BXD-KTQH issued by Ministry of Construction dated March 10, 2003. Despite their certain efficiency and value, the current criteria have not shown how the flooding spots affect traffic and not clarified how to measure or determine the parameters as a basis for flood classification, etc. Therefore, the Ministry of Construction has ordered the research team to develop a set of quantitative criteria for evaluating and classifying the street flooding spots in Vietnam. Accordingly, this paper presents the results of the study in contribution to more effective management of urban infrastructure.

A new solution using ultra-high performance concrete (UHPC) sheet piles was a hard wall structure combined with gabion groyne dams for the purpose of shore protection, sand accretion, and tourist beach creation was proposed in this study. The proposed approach was then applied to meet the both shore protection and sandy beach generation requirements of private Rung Duong resort project in Ba Ria-Vung Tau, Vietnam. The UHPC sheet piles reinforced by fiber reinforcement polymer (FRP) installed in form of a vertical wall were designed and constructed for the shore protection purpose. Together with the later built gabion groyne dam system, the combined structure brought a very good coastal protection effect. As a result observed from Rung Duong resort, the shoreline was pushed back out very far from the resort, while sandy beaches in front of the resort were formed and expanded widely.

Antimicrobial drug resistance occurs when bacteria undergo certain modifications to eliminate the effectiveness of drugs, chemicals, or other agents designed to cure infections. To date, the burden of resistance has remained one of the major clinical concerns as it renders prolonged and complicated treatments, thereby increasing the medical costs with lengthier hospital stays. Of complex causes for bacterial resistance, there has been increasing evidence that proved the significant role of efflux pumps in antibiotic resistance. Coadministration of Efflux Pump Inhibitors (EPIs) with antibiotics has been considered one of the promising ways not only to improve the efficacy but also to extend the clinical utility of existing antibiotics. This chapter begins with outlining current knowledge about bacterial efflux pumps and drug designs applied in identification of their modulating compounds. Following, the chapter addresses and provides a discussion on Quantitative Structure-Activity Relationship (QSAR) analyses in search of novel and potent efflux pump inhibitors.

In recent decades, the nuclear export market has observed a marked shift of demand from traditional customers in the Western world to Asia. The lack of projects in the United States, the delay in the French construction of advanced reactors, and the Fukushima accident in Japan have also led to the declining export capabilities of their companies. In contrast, Russia has gained numerous contracts, and China will likely become another major exporter. In this paper, the evolution of the market was examined from both the supply and demand sides with issues including the more concentrated and uncertain market, the lack of full participation by emerging suppliers to the nonproliferation regime, and the lesser governance capabilities of the newcomers. Addressing these issues, a range of policy suggestions was made, including the reinforcement of market shares of Western suppliers, the encouragement of newcomers to adhere to international norms, and a better safeguards contribution scheme.

This paper examines the relationships between macroscopic determinants (typically, monetary policies) and microscopic factors (mainly, cash flows and other controlling variables) on corporate investment. By employing system-GMM estimation for the 250 Vietnamese non-financial firms, the authors find that the expansionary monetary policy not only encourages the borrowing activities but also results in more corporate investment activities over the period from 2006 to 2016. Noticeably, the internal cash flow is also significant factor, which enhances the activities of corporate investment. Finally, there are differences between internal cash flow effects on corporate investments between two groups, divided by three theoretical criteria. To recapitulate, our implications highlight the importance of monetary policy stability for sustainable growth in corporate investment in Vietnam.

This paper proposes a novel framework, named HIgh-order Substate Chain (HISC) modeling, to capture the entire system dynamics underlying the transaction time series, where the transaction contains explosive states due to the combinatorics of massively observed inputs. In a practical situation, the objective system consists of multiple subsystems where a state of each subsystem is represented by a subset of the transaction. Thus, a transaction observed from the entire objective system is considered to be a collection of such subsets, and each subset is called a "substate" of the objective system. The basic task of our HISC modeling is to efficiently and simultaneously identify the substates and their transitions embedded in the time series. For application, the methods for system dynamics simulation and substate prediction by using the HISC model have been developed. Its significant performance has been confirmed through the evaluation on synthetic data, the comparisons with some High-order Markov chain models in the state of the art and the application to practical data analysis.

International audience; The two-echelon location-routing problem (LRP-2E) is raised by the design of transportation networks with two types of trips: first-level trips serving from one main depot a set of satellite depots, to be located, and second-level trips supplying customers from these satellites. In the proposed multi-start iterated local search (MS-ILS), three greedy randomized heuristics are used cyclically to get initial solutions. Each ILS run alternates between two search spaces: LRP-2E solutions, and travelling salesman (TSP) tours covering the main depot and the customers. The number of iterations allotted to a run is reduced whenever a known solution (stored in a tabu list) is revisited. MS-ILS can be reinforced by a path-relinking procedure (PR), used internally for intensification, as post-optimization, or both. On two sets with 24 and 30 LRP-2E instances, MS-ILS outperforms on average two GRASP algorithms and adding PR brings a further improvement. Our metaheuristic also surpasses a tabu search on 30 instances for a more general problem with several main depots. It is still effective on a particular case, the capacitated location-routing problem (CLRP): In a comparison with four published metaheuristics, only one (LRGTS, Prins et al., 2007) does better.

International audience; The two-echelon location-routing problem (LRP-2E) arises from recent transportation applications like city logistics. In this problem, still seldom studied, first-level trips serve from a main depot a set of satellite depots, which must be located, while second-level trips visit customers from these satellites. After a literature review on the LRP-2E, we present four constructive heuristics and a hybrid metaheuristic: A greedy randomized adaptive search procedure (GRASP) complemented by a learning process (LP) and path relinking (PR). The GRASP and learning process involve three greedy randomized heuristics to generate trial solutions and two variable neighbourhood descent (VND) procedures to improve them. The optional path relinking adds a memory mechanism by combining intensification strategy and post-optimization. Numerical tests show that the GRASP with LP and PR outperforms the simple heuristics and an adaptation of a matheuristic initially published for a particular case, the capacitated location-routing problem (CLRP). Additional tests on the CLRP indicate that the best GRASP competes with the best metaheuristics published.

This paper proposes novel principles and techniques of a particle filter to estimate dynamic system states under an observed time series data and a state-space model which are possibly non-linear and have the dimensions more than several hundreds. First, we point out two crucial curses of dimensionality and propose three key ideas to overcome them. Second, we propose the novel particle filters implementing these ideas and analyse their mathematical characteristics. Our experimental evaluation demonstrates their significant accuracy, robustness and efficiency for both artificial and real-world problems having large scales.

In the current Vietnamese urban, there are existences of two close at-grade intersections, which are defined as double-intersections. Traffic congestion at these intersections occurs frequently, especially in rush hours. The most considered concern is the short distance between two junctions, which makes the confliction to the mixed flow in this space. This paper presents two methods for designing signalized double-intersections and their application for a case study of Lang - Lang Ha - Le Van Luong - Nguyen Ngoc Vu double-intersections. Based on acceptable results, the methods can be potentially implemented for double-intersection design in the large scale in Vietnam, especially, in the places where modern software is not used widely for designing intersections.