Use of nanomaterials in the pretreatment of water samples for environmental analysis

The challenge of providing clean drinking water is of enormous relevance in today’s human civilization, being essential for human consumption, but also for agriculture, livestock and several industrial applications. In addition to remediation strategies, the accurate monitoring of pollutants in water sup-plies, which most of the times are present at low concentrations, is a critical challenge. The usual low concentration of target analytes, the presence of in-terferents and the incompatibility of the sample matrix with instrumental techniques and detectors are the main reasons that renders sample preparation a relevant part of environmental monitoring strategies. The discovery and ap-plication of new nanomaterials allowed improvements on the pretreatment of water samples, with benefits in terms of speed, reliability and sensitivity in analysis. In this chapter, the use of nanomaterials in solid-phase extraction (SPE) protocols for water samples pretreatment for environmental monitoring is addressed. The most used nanomaterials, including metallic nanoparticles, metal organic frameworks, molecularly imprinted polymers, carbon-based nanomaterials, silica-based nanoparticles and nanocomposites are described, and their applications and advantages overviewed. Main gaps are identified and new directions on the field are suggested.publishe

2011 30th IEEE International Symposium on Reliable Distributed Systems Process Implanting: A New Active Introspection Framework for Virtualization

Abstract—Previous research on virtual machine introspection proposed “out-of-box ” approach by moving out security tools from the guest operating system. However, compared to the traditional “in-the-box ” approach, it remains a challenge to obtain a complete semantic view due to the semantic gap between the guest VM and the hypervisor. In this paper, we present Process Implanting, a new active VM introspection framework, to narrow the semantic gap by implanting a process from the host into the guest VM and executing it under the cover of an existing running process. With the protection and coordination from the hypervisor, the implanted process can run with a degree of stealthiness and exit gracefully without leaving negative impact on the guest operating system. We have designed and implemented a proof-of-concept prototype on KVM which leverages hardware virtualization. We also propose and demonstrate application scenarios for Process Implanting in the area of VM security. Keywords-Security; Virtualization; Active VM introspection I

Dynamics of Paddy Field Patterns in Response to Urbanization: A Case Study of the Hang-Jia-Hu Plain

Urban land has increasingly expanded and encroached upon a significant number of paddy fields in Hang-Jia-Hu Plain, due to the rapid socio-economic development and agro-pedoclimatic conditions favorable to rice cultivation and human settlement. Although many studies have analyzed the characteristics of urban land expansion, relatively less attention has been paid to exploring the various urban expansion patterns and the impact of different urban expansion patterns on paddy field at a regional scale. This paper characterized the changing patterns of paddy fields in response to various urban expansion patterns in the Hang-Jia-Hu Plain integrating geographic information systems, gradient analyses and landscape metrics. Our results demonstrate that the amount of urban land expanded to nearly four times that of the initial area during 1980–2010 and that 88% of new urban land was developed on paddy fields. Of the total area of paddy fields, paddy fields of level I accounted for 96%. Moreover, various urban expansion styles differentially influenced the patterns of paddy fields. In autonomous expansion cities, sprawled urban land mainly occupied paddy fields in urban centers. However, the irregular expansion of passive expansion cities encroached on a number of paddy fields in the urban fringe where the landscape of urban patches and paddy fields was more complex and irregular in shape. Furthermore, the urbanization curve implies that future urbanization efforts will focus on the passive expansion cities, indicating that paddy fields still face the risk of disruption. We suggest that the boundary of urban development should be restricted, permanent paddy reserves should be delimited, and ecologically oriented management systems that target paddy field protection should be implemented to ensure the sustainable development of this region. This work improved the understanding of the urbanization process that governed paddy fields dynamics, and provides a scientific basis for decision-making processes to achieve regional sustainability

A Novel Color Image Encryption Algorithm Using Coupled Map Lattice with Polymorphic Mapping

Some typical security algorithms such as SHA, MD4, MD5, etc. have been cracked in recent years. However, these algorithms have some shortcomings. Therefore, the traditional one-dimensional-mapping coupled lattice is improved by using the idea of polymorphism in this paper, and a polymorphic mapping–coupled map lattice with information entropy is developed for encrypting color images. Firstly, we extend a diffusion matrix with the original 4 × 4 matrix into an n × n matrix. Then, the Huffman idea is employed to propose a new pixel-level substitution method, which is applied to replace the grey degree value. We employ the idea of polymorphism and select f(x) in the spatiotemporal chaotic system. The pseudo-random sequence is more diversified and the sequence is homogenized. Finally, three plaintext color images of 256×256×3, “Lena”, “Peppers” and “Mandrill”, are selected in order to prove the effectiveness of the proposed algorithm. The experimental results show that the proposed algorithm has a large key space, better sensitivity to keys and plaintext images, and a better encryption effect