The Earth's human population is expected to pass eight billion by the year 2025, while rapid growth in the global economy will spur ever increasing demands for natural resources. The world will ...consequently face growing scarcities of such vital renewable resources as cropland, fresh water, and forests. Thomas Homer-Dixon argues in this sobering book that these environmental scarcities will have profound social consequences—contributing to insurrections, ethnic clashes, urban unrest, and other forms of civil violence, especially in the developing world. Homer-Dixon synthesizes work from a wide range of international research projects to develop a detailed model of the sources of environmental scarcity. He refers to water shortages in China, population growth in sub-Saharan Africa, and land distribution in Mexico, for example, to show that scarcities stem from the degradation and depletion of renewable resources, the increased demand for these resources, and/or their unequal distribution. He shows that these scarcities can lead to deepened poverty, large-scale migrations, sharpened social cleavages, and weakened institutions. And he describes the kinds of violence that can result from these social effects, arguing that conflicts in Chiapas, Mexico and ongoing turmoil in many African and Asian countries, for instance, are already partly a consequence of scarcity.
This is the first environmental history of China during the three thousand years for which there are written records. It is also a treasure trove of literary, political, aesthetic, scientific, and ...religious sources, which allow the reader direct access to the views and feelings of the Chinese people toward their environment and their landscape.Elvin chronicles the spread of the Chinese style of farming that eliminated the habitat of the elephants that populated the country alongside much of its original wildlife; the destruction of most of the forests; the impact of war on the environmental transformation of the landscape; and the re-engineering of the countryside through water-control systems, some of gigantic size. He documents the histories of three contrasting localities within China to show how ecological dynamics defined the lives of the inhabitants. And he shows that China in the eighteenth century, on the eve of the modern era, was probably more environmentally degraded than northwestern Europe around this time.Indispensable for its new perspective on long-term Chinese history and its explanation of the roots of China's present-day environmental crisis, this book opens a door into the Chinese past.
On the basis of an examination of the colonial mercury and silver production processes and related labor systems, Mercury, Mining, and Empire explores the effects of mercury pollution in colonial ...Huancavelica, Peru, and Potosí, in present-day Bolivia. The book presents a multifaceted and interwoven tale of what colonial exploitation of indigenous peoples and resources left in its wake. It is a socio-ecological history that explores the toxic interrelationships between mercury and silver production, urban environments, and the people who lived and worked in them. Nicholas A. Robins tells the story of how native peoples in the region were conscripted into the noxious ranks of foot soldiers of proto-globalism, and how their fate, and that of their communities, was-and still is-chained to it.
The cycle life of lithium-ion batteries was investigated using a modified USABC electric vehicle testing protocol designed to simulate the effect of a hybrid energy-storage system (ultracapacitor and ...battery) in a plug-in hybrid electric vehicle. A side-by-side comparison of battery capacity and impedance changes with and without the effect of the ultracapacitor was performed. Calendar-life degradation effects were corrected for using control cells. The battery's rate of cycle-related capacity degradation decreased by a factor of 2 and rate of cycle-related impedance degradation, by a factor of 5.9 when exposed to the ultracapacitor-modified profile. The modified profile avoids exposure to regeneration energy and reduces maximum voltage of the battery.
Abstract The emergence of the social awareness about the necessary preservation of natural spaces has led to the engagement of different actors which have been involved in an attempt to counter their ...degradation and disappearance. Through the primary documentary search it is intended to trace the precise moment when the break between the human being and the natural environment where he lived and to show the way in which this evolution began to be tangible in Zaragoza during the Late Middle Ages. Keywords Natural spaces; Zaragoza; anthropic pressure; spatial humanization; natural degradation. 1.INTRODUCCIÓN Hasta décadas recientes, en las que la sociedad ha mostrado una creciente concienciación hacia la conservación y protección del Medio Ambiente, la acción humana ha provocado el retraimiento, la degradación y la desaparición de un importante número de entornos naturales. Un ejemplo de ello es el paulatino desmantelamiento de los espacios naturales vinculados en mayor o menor medida con el agua, caso de las ramblas, lejas, sotos y cañaverales, a los que deberían añadirse las riberas fluviales, especialmente en lo que a sus tramos urbanos se refiere.
A series of hierarchical Bi sub(12)TiO sub(20)-grap hene nanoarchitectures (Bi sub(12)TiO sub(20)-GR) with GR loadings from 1% to 10% are fabricated by a single-step solvothermal treatment technique, ...and the intimate interfacial contact between flexible GR sheets and flower-like Bi sub(12)TiO sub(20) nanocrystals is observed in the Bi sub(12)TiO sub(20)-GR composites. As a novel composite photocatalyst, Bi sub(12)TiO sub(20)-GR with GR loading of 2% possesses the highest simulated sunlight photocatalytic activity towards the degradation of two typical organic pollutants, methyl orange (MO) and p-nitrophenol (PNP). Furthermore, the separation and transportation of the photogenerated carriers in the simulated sunlight-irradiating Bi sub(12)TiO sub(20)-GR system is studied, meanwhile, the active species (h sub(VB) super(+), O sub(2)&z.rad; super(-) and &z.rad; OH) generated in the Bi sub(12)TiO sub(20)-GR-p hotocatalyzed PNP degradation system are identified by free radical and hole scavenging experiments. Based on the experimental and theoretical results, the mechanism and pathway of photocatalytic degradation of PNP in the simulated sunlight-irradiating Bi sub(12)TiO sub(20)-GR system are proposed.
Non-doped and La-doped ZnTiO sub(3) nanoparticles were successfully synthesized viaa modified sol-gel method. The synthesized nanoparticles were structurally characterized by PXRD, UV-vis DRS, FT-IR, ...SEM-EDS, TEM, Raman and photoluminescence spectroscopy. The results show that doping of La into the framework of ZnTiO sub(3) has a strong influence on the physico-chemical properties of the synthesized nanoparticles. XRD results clearly show that the non-doped ZnTiO sub(3) exhibits a hexagonal phase at 800 degree C, whereas the La-doped ZnTiO sub(3) exhibits a cubic phase under similar experimental conditions. In spite of the fact that it has a large ionic radius, the La is efficiently involved in the evolution process by blocking the crystal growth and the cubic to hexagonal transformation in ZnTiO sub(3). Interestingly the absorption edge of the La-doped ZnTiO sub(3) nanoparticles shifted from the UV region to the visible region. The photocatalytic activity of the La-doped ZnTiO sub(3) nanoparticles was evaluated for the degradation of Rhodamine B under sunlight irradiation. The optimum photocatalytic activity was obtained for 2 atom% La-doped ZnTiO sub(3), which is much higher than that of the non-doped ZnTiO sub(3) as well as commercial N-TiO sub(2). A possible mechanism for the degradation of Rhodamine B over La-doped ZnTiO sub(3) was also discussed by trapping experiments. More importantly, the reusability of these nanoparticles is high. Hence La-doped ZnTiO sub(3) nanoparticles can be used as efficient photocatalysts for environmental applications.
The stability of perovskite proton conductors BaCe0.2Zr0.7Y0.1O2.95 and BaCe0.5Zr0.4Y0.1O2.95 (referred to as BCZY) has been tested by exposure of powders to water and ethanol at room temperature. ...The liquid phase was monitored as a function of time with inductively coupled plasma-optical emission spectrometry. With water, leaching of barium continued for over 200 days, the duration of the test. There was no systematic difference in leaching with solutions of native pH or alkalified with NH4OH. The powders, before and after treatment, were investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). TEM confirmed the degradation of the perovskite phase and revealed barium carbonate nanobranches and nanoparticles from the agglomeration of the fragmented perovskite. The effect of ethanol was much less severe; leaching of elements after immersion was negligible for up to 17 days, and XRD patterns before and after treatment did not show any structural degradation. It is concluded that ethanol is an appropriate choice as a processing solvent for tapecasting BCZY powders.
CeO sub(2)/TiO sub(2) nanobelt heterostructures are synthesized via a cost-effective hydrothermal method. The as-prepared nanocomposites consist of CeO sub(2) nanoparticles assembled on the rough ...surface of TiO sub(2) nanobelts. In comparison with P25 TiO sub(2) colloids, surface-coarsened TiO sub(2) nanobelts, and CeO sub(2) nanoparticles, the CeO sub(2)/TiO sub(2) nanobelt heterostructures exhibit a markedly enhanced photocatalytic activity in the degradation of organic pollutants such as methyl orange (MO) under either UV or visible light irradiation. The enhanced photocatalytic performance is attributed to a novel capture-photodegradation-release mechanism. During the photocatalytic process, MO molecules are captured by CeO sub(2) nanoparticles, degraded by photogenerated free radicals, and then released to the solution. With its high degradation efficiency, broad active light wavelength, and good stability, the CeO sub(2)/TiO sub(2) nanobelt heterostructures represent a new effective photocatalyst that is low-cost, recyclable, and will have wide application in photodegradation of various organic pollutants. The new capture-photodegradation-release mechanism for improved photocatalysis properties is of importance in the rational design and synthesis of new photocatalysts. The enhanced photocatalytic performance of CeO sub(2)/TiO sub(2) heterostructured nanobelts is attributed to a novel capture-photodegradation-release degradation mechanism. During the photocatalytic process, MO molecules are captured by CeO sub(2) nanoparticles on the surface of the heterostructure, then quickly photodegraded under UV or visible light irradiation, and ultimately the degradation products are released to external environment.
éditorial
Politique étrangère,
07/2021
2
Journal Article
Recenzirano
Il faut se pencher sur l'Asie du Sud-Est - au sens large, en allant jusqu'a l'Australie, de plus en plus insérée dans les grands montages stratégiques de la région -, sur les relations ...qu'entretiennent les pays tres divers de cette zone avec Pékin, pour imaginer l'avenir d'une région déterminante a la fois économiquement et politiquement, et tenter de cerner au plus pres les objectifs et les moyens des stratégies chinoises. On peut déja la voir comme un espace ou s'affirme sans fard la puissance chinoise, et ou s'articulent les réponses des autres : défenses concretes (militaires, contre la désinformation et les manœuvres d'influence, contre les cybermenaces; économiques contre des emprises prédatrices...), architectures diplomatiques (meme si l'on sait que la zone ne se détachera pas de la Chine, ne peut exister contre la Chine), invention de regles de coexistence avec une nouvelle puissance. Autrement dit, les zones d'influence existent, et se renforcent - meme si les résultats ne sont pas toujours positifs, comme en témoigne la réelle degradation de l'image internationale de la Chine.
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