Links between particle surface hardening and rehydration impairment during micellar casein powder storage

Storage is an unavoidable critical phase regarding dairy powder reconstitution abilities, particularly for high casein content powders, which generally present a poor rehydration behavior. The ability of micellar casein powders to completely rehydrate can thus be particularly affected by storage time and temperature. To implement best practices for the optimization of storage conditions, understanding changes occurring is a crucial point. For the first time, biophysical techniques were used to investigate powder surface at the nanoscale. Atomic force microscopy revealed that particle surface became rougher during storage, associated with the formation of hollow zones (around 500 nm) holes when stored for 10 months at 40 °C. Mechanical properties of micellar casein particle surface during powder storage was quantified using AFM nanoindentation. Spatially-resolved force/indentation curves evidenced a significant stiffer surface for aged powder (Young modulus of ∼20 GPa) in comparison with the fresh one (∼0.2 GPa). These findings were fully consistent with the formation of a crust at the powder surface observed by high-resolution field-emission scanning electron microscopy during powder rehydration. Finally, alterations of the rehydration process can be related to modifications occurring at the particle surface during storage

Worker, peasant or entrepreneur? Analysis of the entrepreneurial logics and practices of family farmers in agrarian reform cooperatives in the SAISS (Morocco)

The aim of this paper is to analyze the emerging entrepreneurial practices and the underlying logic of family farms in two agrarian reform cooperatives in Morocco. These practices can be explained by the constant negotiation of multiple and sometimes even antagonistic logics (peasant, entrepreneurial, proletarian, capitalistic) within these farms in a context of rapid agrarian change and a juxtaposition of different farm types on the same territory. Five factors illustrate this emergence: (1) the access to credit, (2) the functioning of the farm (rotation of the crops, use of inputs, workforce), 3) the access to groundwater resources, (4) the marketing practices adopted by farmers and (5) the informational factors. The porosity of the peasant and entrepreneurial worlds is the main lesson we can draw from our study. There is a subtle process of hybridization between the peasant and entrepreneurial modes of farming, with a wide range of profiles, ranging from a pure 'peasant', to a pure 'entrepreneur' and in between the peasant-entrepreneur and the entrepreneur-peasant. If we only focus on the political discourse, the trend in the development of new modes of farming seems inescapable. Our study stresses the resistance of practices and logics of peasant modes of farming which can mix with a 'modern' vision of agriculture. However, the siren songs of entrepreneurship can lead to bankruptcy, an exit from agriculture, which could have a strong impact on the social cohesion of the Moroccan society, particularly in rural areas. (Résumé d'auteur

Linking a simulated annealing based optimization model with PHT3D simulation model for chemically reactuve transport processes to optimally characterize unknown contaminant sources in a former mine site in Australia

Historical mining activities often lead to continuing wide spread contaminants in both groundwater and surface water in previously operational mine site areas. The contamination may continue for many years after closing down the mining activities. The essential first step for sustainable management of groundwater and development of remediation strategies is the unknown contaminant source characterization. In a mining site, there are multiple species of contaminants involving complex geochemical processes. It is difficult to identify the potential sources and pathways incorporating the chemically reactive multiple species of contaminants making the source characterization process more challenging. To address this issue, a reactive transport simulation model PHT3D is linked to a Simulated Annealing based the optimum decision model. The numerical simulation model PHT3D is utilized for numerically simulating the reactive transport process involving multiple species in the former mine site area. The simulation results from the calibrated PHT3D model are illustrated, with and without incorporating the chemical reactions. These comparisons show the utility of using a reactive, geochemical transport process’ simulation model. Performance evaluation of the linked simulation optimization methodology is evaluated for a contamination scenario in a former mine site in Queensland, Australia. These performance evaluation results illustrate the applicability of linked simulation optimization model to identify the source characteristics while using PHT3D as a numerical reactive chemical species’ transport simulation model for the hydro-geochemically complex aquifer study area

Extraction of a tricarboxylic acid from a sugar-cane by-product – Study and modeling of the anion-exchange step

Extraction of a tricarboxylic acid from a sugar-cane by-product – Study and modeling of the anion-exchange step . 16. Congrès de la Société Française de Génie des Procédés "Le Génie des Procédés au Service de l'Homme" (SFGP 2017

Effects of Age and Task Load on Drivers’ Response Accuracy and Reaction Time When Responding to Traffic Lights

International audienceDue to population aging, elderly drivers represent an increasing proportion of car drivers. Yet, how aging alters sensorimotor functions and impacts driving safety remains poorly understood. This paper aimed at assessing to which extent elderly drivers are sensitive to various task loads and how this affects the reaction time (RT) in a driving context. Old and middle-aged people completed RT tasks which reproduced cognitive demands encountered while driving. Participants had to detect and respond to traffic lights or traffic light arrows as quickly as possible, under three experimental conditions of incremental difficulty. In both groups, we hypothesized that decision-making would be impacted by the number of cues to be processed. The first test was a simple measure of RT. The second and third tests were choice RT tasks requiring the processing of 3 and 5 cues, respectively. Responses were collected within a 2 s time-window. Otherwise, the trial was considered a no-response. In both groups, the data revealed that RT, error rate (incorrect answers), and no-response rate increased along with task difficulty. However, the middle-aged group outperformed the elderly group. The RT difference between the two groups increased drastically along with task difficulty. In the third test, the rate of no-response suggested that elderly drivers needed more than 2 s to process complex information and respond accurately. Both prolonged RT and increased no-response rate, especially for difficult tasks, might attest an impairment of cognitive abilities in relation to aging. Accordingly, casual driving conditions for young drivers may be particularly complex and stressful for elderly people who should thus be informed about the effects of normal aging upon driving

Structure of the {001} talc surface as seen by atomic force microscopy: Comparison with X-ray and electron diffraction results

In this study the surface structure of a centimetre sized crystal of talc from the Trimouns deposit (Ariège, France) was imaged by atomic force microscopy. The direct image shows detailed characteristics of clay tetrahedral surfaces. The unit-cell dimensions obtained 30 using atomic force microscopy (aor = 5.47±0.28 and bor = 9.48±0.28 Å) are found to be slightly higher, with an increased uncertainty, than those obtained using X-ray diffraction (aor = 5.288±0.007 and bor = 9.159±0.010 Å) and selected-area electron diffraction (aor = 5.32±0.03 and bor = 9.22±0.05 Å). Talc has a quasi-ideal surface, clean of strong 34 structural distortion as compared to most of other clay minerals and unlikely surface 35 relaxation. The observation on the obtained image of apparent cell dimension enlargement is 36 then more likely attributed to instrumental artefacts, also responsible for scattered values of unit-cell parameters rather than related to any surface structural features