Serpentine is widely distributed in the regolith and occurs in different types (chrysotile, lizardite, antigorite). The physical and chemical processes such as composition dissolution and structure evolution of serpentine occur constantly under the action of aqueous solutions. Based on the similarities and differences of polysomic structures and properties of chrysotile (tubular shapes) and lizardite (flat structural layers), the mineral–water interfacial reaction of these two minerals was carried out in a sulfuric acid solution with a concentration of 1 mol L–1. The mineral samples were characterized by powder X-ray diffraction, Fourier-transform infrared spectroscopy, scanning and transmission electron microscopy, Brunauer–Emmett–Teller surface area analysis, magic angle spinning nuclear magnetic resonance, and inductively coupled plasma mass spectrometry. The Si, Mg, and Fe dissolution concentrations, dissolution rates, and dissolution rules and structural changes of chrysotile and lizardite were studied and compared. The results show that H+ is more aggressive toward lizardite in sulfuric acid solution. The dissolution rate of Si, Mg, and Fe was faster, the dissolution concentration was greater, and structural changes occurred preferentially in lizardite. Specifically, Mg dissolved first in the octahedral sheets, and Si and Fe dissolved later in the tetrahedral sheets. After the water interfacial reaction with the sulfuric acid solution, the ion dissolution rates of both chrysotile and lizardite were Mg > Fe > Si. In summary, this work investigates the mineral–water interfacial reaction of chrysotile and lizardite in sulfuric acid media from different crystal structures and demonstrates that the crystal structure has a significant effect on the acid reactivity of lizardite minerals. Furthermore, the crystal chemistry patterns for the structural dissociation of different two-dimensional structural units were studied. This work provides a mineralogical basis for the study of the mechanisms of ion migration and crystal-structure evolution of serpentine under acidic media.

Acid activation of clay minerals is one of the most effective methods for production of materials with increased acidity and porosity. In this review, the benefits of infrared (IR) spectroscopy in studies of acid-treated clay minerals are demonstrated. Protons penetrating into the clay mineral layers evoke structural modifications that can be followed readily by changes in the characteristic absorption bands attributed to the vibrations of the OH and Si–O groups. In the first part of the review the effect of the clay mineral type, composition, layer charge, non-swelling layers, and organo-modification on the dissolution rate is reported. The identification of the acid sites via pyridine adsorption also included. The purpose was to gather the IR results published in previous studies in a single summary paper. In the second part select recent studies reporting the utilization of IR spectroscopy for the characterization of acid-activated clay minerals, mainly applied as catalysts or adsorbents, are discussed. IR spectroscopy as a simple and non-destructive technique deserves attention also today.

Materials in a high radioactive environment undergo structural changes. X-ray diffraction (XRD) is commonly used to study the micro-structural changes of such materials. Therefore, a safe procedure is required for the preparation of specimens. In this paper, a simple methodology for the preparation of radioactive powder specimens to be analyzed in a non-nuclearized laboratory diffractometer is presented. The process is carried out inside a shielded glove box, where the milling of the radioactive sample and specimen preparation occurs. Minimum amount of sample is required (<20 mg), which is drop-casted on a polyether ether ketone (PEEK) foil and glue-sealed inside a disposable plastic holder for a safe handling of the specimen. One example using neutron-irradiated granite is shown, where unit-cell parameters and crystal density of the main phases were calculated. The developed methodology represents an easy and affordable way to study neutron irradiated materials with low activity at laboratory scale.

The effect of mechanical activation on the ion-exchange selectivity of natural zeolites from Russia, namely clinoptilolite-bearing tuffs and chabazites, was studied. The structural modifications and thermal properties were investigated, and the specific surface area and porosity of mechanically activated zeolites were determined. At activation doses of up to 1.0 kJ g–1 the main processes are the breakdown of the zeolite particles and pore structure changes. At greater activation doses amorphization takes place. It was shown that during the initial stage of activation in most cases the clinoptilolite selectivity for Sr2+ increased slightly and then decreased; the selectivity for Cu2+ increased 100 times; and the selectivity of chabazite-1 for Sr2+ increased 300 times.

We present a set of theoretical and empirical papers and briefly describe the specific contributions to the Macroeconomic Dynamics special issue on technology aspects in the process of development.

During the last decades, the Mediterranean shallow-water benthic communities have experienced significant changes in taxa composition and distribution. These variations were related to a complex set of anthropogenic stressors as well as to mass mortality events starting from 1999 and related to the current climatic changes. To evaluate the effect of these changes on long-living species with a limited larval dispersal capacity, a quantitative and qualitative monitoring of the shallow-water hard bottom community structure was performed over a pluri-decennial interval of time. The aim of this work was the comparison of the quali-quantitative occurrence and seasonal cycles of several benthic taxa living on a rocky cliff of the Portofino Promontory (eastern Liguria, Mediterranean Sea), from 15 to 20 m depth. The studied community, within a Lithophyllo–Halimedetum tunae association, was analysed by sets of photographs repeated, exactly in the same site, at 25 years of distance (1987/88 and 2012/13). The results suggest that the macroalgal coverage of the surveyed cliff suffered, during the monitored span of time, a significant depletion in quali-quantitative terms, while the overall sponge coverage remained almost unvaried. Nevertheless, a discrete analysis of the most common sponge species present in the study area showed significant variations, with some taxa now more abundant (Axinella spp. and Agelas oroides), some virtually stable (Cliona viridis and the complex of red encrusting sponges), and others drastically depleted (Chondrosia reniformis, Phorbas tenacior, Acanthella acuta, Ircinia spp., Dysidea avara and Petrosia ficiformis). Finally, some sponge species showed clear seasonal cycles indicating recruitment periods and post-recruit mortalities.

A descriptive analysis and a survey of literature were used in this assessment of the transformation of the structure of production agriculture. The changes in production agriculture have important implications for resource use, population distribution in rural communities, and the survival of small farms. The shifting structural change in production agriculture as a response to economic and technological adjustments is not a temporary phenomenon. The economic and natural base of agriculture will change toward greater capital intensity and concentration of ownership, and will raise public policy questions in relation to the survival of a large farm population.

Cotton and synthetic fiber competition in textile mills between 1961-1990 was examined using a time-varying parameter regression model. Results indicate that the structure of demand for cotton is not stable and cotton's share responses to changes in the prices of cotton and synthetic fiber vary over time. Cotton and synthetic fiber competition in textile mill use is essentially between cotton and noncellulosic fiber. Cellulosic fiber is not a cotton competitor.

This study used aggregated data for fresh vegetables and fresh fruits toanalyze how trade flows in the fresh produce industry have changed undertrade agreements and to assess the potential implications to nutritionpolicies in the United States. The first part of the analysis uses aBai-Perron test to endogenously determine any structural break points invegetable and fruit trade movements and prices. Directed acyclic graphs andhistorical decompositions are used to establish causal patterns oninnovations from vector autoregression models fitted to annual observationsof trade flows, prices, and income. The results showed that trade agreementshave had significant impacts to the produce industry. Income was a majordeterminant of domestic fruit production and imports.

Remarkable changes have occurred over the years in the domestic andinternational economic environment of the fruit and vegetable industry.These changes are partly driven by the North American Free Trade Agreement,nutrition policies, and development and enforcement of new food safetystandards. The articles in this invited session examined the effect of thesedrivers and their implication on the future competitiveness of the southernfruit and vegetable industry.

The increase in the ageing population has generated much interest and research into what constitutes normal ageing. By identifying normal ageing processes it is hoped it will be possible to distinguish risk factors for the development of abnormal or premature ageing.

This review discusses biological, structural and mechanical changes in the cardiovascular system with ageing that are thought to increase the risk of cardiovascular disease with ageing. Contributory factors are thought to be genetic and lifestyle related. Measurements of biological as opposed to chronological ageing such as vascular stiffness are explored as a possible useful predictor of cardiovascular morbidity and mortality, indicating its possible utilization as a non-invasive screening tool in older people.

The identification of those at risk of cardiovascular disease and modification of risk factors may minimize interactions of the ageing process and therefore reduce the incidence of cardiovascular disease within the UK population.

We consider linear elliptic systems which arisein coupled elastic continuum mechanical models. In these systems, the straintensor ε P := sym (P -1∇u) is redefined to include amatrix valued inhomogeneity P(x) which cannot be described by a spacedependent fourth order elasticity tensor. Such systems arise naturally ingeometrically exact plasticity or in problems with eigenstresses.The tensor field P induces a structural change of the elasticity equations. Forsuch a model the FETI-DP method is formulated and a convergence estimateis provided for the special case that P -T = ∇ψ is a gradient.It is shown that the condition number depends only quadratic-logarithmicallyon the number of unknowns of each subdomain. Thedependence of the constants of the bound on P is highlighted. Numericalexamples confirm our theoretical findings. Promising results are also obtainedfor settings which are not covered by our theoretical estimates.