Behavior of Paramagnetic Iron during the Thermal Transformations of Kaolinite

Kaolinites with various degrees of structural order and iron content were heated and subsequently analyzed via electron paramagnetic resonance. Iron was present in two different states in the heated materials, either as dilute structural Fe³⁺ ions or in concentrated Fe³⁺ phases. During metakaolinization, the environment of dilute Fe³⁺ ions changed, following modifications of the Al³⁺ coordination, and the Fe³⁺ concentration increased. With the breakdown of metakaolinite, the diffusion of Fe³⁺ ions induced their exsolution in superparamagnetic iron-rich domains (Fe³⁺ clusters in γ-Al₂O₃ and/or Fe³⁺ oxide nanophases), which produced a decrease in the dilute Fe³⁺ concentration. The subsequent breakdown of γ-Al₂O₃ and the formation of mullite made the dilute Fe³⁺ concentration increase again, because of the incorporation of Fe³⁺ ions in the mullite structure.     

Study of Deformation Mechanisms in Titanium by Interrupted Rolling and Channel Die Compression Tests

The mechanisms of small plastic deformation of titanium (T40) during cold rolling and channel die compression by means of "interrupted in situ" EBSD orientation measurements were studied. These interrupted EBSD orientation measurements allow to determine the rotation flow field which leads to the development of the crystallographic texture during the plastic deformation. Results show that during rolling, tension twins and compression twins occur and various glide systems are activated, the number of grains being larger with twins than with slip traces. In channel die compression, only tension twins are observed in some grains, whereas slip traces can be spotted in almost all observed grains. The different stress conditions and different strain rates existing under the two modes of deformation lead to the activation of different deformation mechanisms.     

Dual approach in non-linear fracture mechanics

A dual approach in fracture mechanics based on complementary energy is proposed. The analysis of the dissipation shows that the thermodynamical force associated with the evolution of a crack is an energy release rate, form of which depends on the presence or not of mechanical discontinuities. This energy release rate is given as a integral based on free or complementary energy. The invariance of sintegrals is analysed and the obtained results in elastoplasticity are discussed. The energy release rate is determined in terms of potential energy or complementary energy, first in elasticity and secondly in elastoplasticity. Associated to these definitions, the law of propagation of the crack is chosen as a Griffith law and the propagation is governed by a normality rule. In this framework we formulate the evolution problem concerning crack propagation in an elastoplastic material. Variational formulations are obtained in terms of rate of displacement, of stresses and of crack length.     

Experimental Investigation of the Hydraulic Erosion of Noncohesive Compacted Soils

This paper presents the results of a laboratory investigation whose purpose was to evaluate the effects of compaction on the erodibility of cohesionless soils. By means of a recently developed flume experiment, sediment erosion rates and incipient motion, as a function of shear stress, average velocity, and dry density, have been determined for three compacted sand and gravel mixtures. A preliminary comparison of the incipient motion values shows that granular soils compacted at the Proctor optimum have a higher resistance to free surface flow erosion than those compacted at lower and higher densities. This leads one to infer that the Proctor optimum, generally used as a standard for construction, might also be an optimum for hydraulic resistance and stability. Additional comparison of the experimental data with two commonly used incipient motion criteria also suggests that Yang’s criterion is a better predictor of soil detachment than the Shields-Yalin criterion.     

Old world and new world wine concepts of terroir and wine: perspectives of three renowned non-French wine makers

The concept of ‘terroir’ has roots steeped in French history of wine and evocative stories of the land. Today terroir is important as a quality marker in brand management for upmarket wines. French wines have benefited from their historical connotation with terroir but other wine growing countries have also adopted the term to mean characteristics in wine attributable to place of origin. However there is no universally accepted definition of terroir except to say it refers to a particular place. This paper addresses this ambiguity by seeking the practice-based views of three experienced non-French winemakers. This reveals a social dimension to terroir that in various degrees supports and extends both the technical/scientific progress and brand value for premium wines in both Old and New World regions. This article contributes to the growing body of research that seeks to understand the practicality of terroir as a marketing and brand value indicator.     

Cassava Starch Processing at Small Scale in North Vietnam

In Northern Vietnam, small‐scale cassava starch processing is conducted in densely populated craft villages, where processors face difficulties to expand their activities. Three different processing systems were studied among a cluster of three communes in the Red River Delta, producing up to 430 t of starch (at 55% dry matter) per day. The first system, type A, is a cylindrical rasper and a manual sieve, the second, type B, is a cylindrical rasper and stirring‐filtering machine and the third, type C, used equipment for both the rasping and filtering stages. Moisture, starch, crude fibers and ash content analysis were carried out on samples collected from the A‐B‐C manufacturing processes to establish the mass balance of starch. Production capacity, water consumption, electrical requirements and capital‐labor costs per tonne of starch (12% moisture) were also reported. A‐B‐C manufacturing processes enabled 75% recovery of the starch present in fresh roots. No significant change was observed in the composition of starch. Upgrading from system A to B and subsequently to C resulted in an increase in the extraction capacities (up to 0.9 t of peeled roots per hour), the extraction efficiencies during the extraction stage (up to 93%), and an increase in the water consumption and electrical power (up to 21 m³ and 55 kWh per tonne of starch, respectively). The highest amount of total solids carried in the waste‐water was obtained with type C (up to 17% of the dry weight of fresh roots, compared to 10% and 13% for type A and B, respectively). This may lead to a higher chemical oxygen demand (COD) and biological oxygen demand (BOD) in waste‐water, which can result in more polluted waste‐water than compared with the type A and B technologies. Upgrading the rasping‐extraction technologies also resulted in higher profits and reduction of labor per tonne of starch (up to 18 US$ and 26 man‐hours respectively). The diagnosis proposed in this study can be applied in different contexts to recommend technological options by considering space, energy and capital‐labor availabilities.     

Geographical origin classification of olive oils by PTR-MS

The volatile compositions of 192 olive oil samples from five different European countries were investigated by PTR-MS sample headspace analysis. The mass spectra of all samples showed many masses with high abundances, indicating the complex VOC composition of olive oil. Three different PLS-DA models were fitted to the data to classify samples into ‘country’, ‘region’ and ‘district’ of origin, respectively. Correct classification rates were assessed by cross-validation. The first fitted model produced an 86% success rate in classifying the samples into their country of origin. The second model, which was fitted to the Italian oils only, also demonstrated satisfactory results, with 74% of samples successfully classified into region of origin. The third model, classifying the Italian samples into district of origin, yielded a success rate of only 52%. This lower success rate might be due to either the small class set, or to genuine similarities between olive oil VOC compositions on this tight scale.     

Economic and environmental assessment on the energetic valorization of organic material for a municipality in Quebec, Canada

Waste-to-energy provides a solution to two problems: waste management and energy generation. An integrated anaerobic waste valorization process is an interesting option, but because of investments cost and low energy value in the province of Quebec, it is hard for a municipality to commit to that solution. This paper investigated the economic possibilities to manage organic material, organic fraction of municipal solid waste, and municipal wastewater sludge by anaerobic digestion for a 150,000 inhabitant municipality, with consideration to energy generation and greenhouse gas emission reduction. Using the biogas to co-generation solution brings a payback time on investment (PBT) of 3.7 years with electricity price at 0.10 $Cdn/kW h. The addition of manure from surrounding farms increases the biogas production by 37%, but increases the PBT to 6.8 years unless the leftover digestate can be used for agronomic valorization; then it becomes economically advantageous. The natural gas purchasing cost is too low to promote the enrichment of biogas into renewable natural gas. However, this scenario has the lowest energetic payback time (3.3 years) and reduces the most greenhouse gas emissions (4261 tCO₂eq/a).