Stability Studies of Agrifood Reference Materials Under Different Conditions of Storage by Near-Infrared Spectroscopy

Reference materials (RM) play an increasingly important role for laboratories. The aim of this work is to compare different conditions of storage and assess the stability of agrifood external reference materials (ERM). These materials could be used as tools by laboratories notably for their quality control procedure. However, as the other RM, their stability must be assessed during stability studies. The determination of the limiting date of stability (LDS), defined as the period during which analytes called marker of stability are still considered as stable, is used on this purpose. The influences of the environmental factor were tested by the application of full experimental designs with two tested environmental factors: the temperature (storage at +4 °C or +20 ± 10 °C) and the composition of the atmosphere (absence or presence of gases in the packaging). Thus, the setting under vacuum increases clearly the stability for the studied analyte. Almost all ERM stored in the best conditions have a determined LDS higher than those stored in current condition of storage. Indeed, the bread wheat ERM LDS is higher than the current storage of 24 months     

Mechanical behaviour of SSRT specimens optimized for IGSCC concerns

Simulating testing conditions leading to evaluate the intergranular stress corrosion cracking sensitivity of structural alloys is crucial to estimate the lifetime of in-service components. Former studies have pointed out that a simple modification of the design of slow strain rate tensile specimens was particularly convenient for evaluating the susceptibility to intergranular stress corrosion cracking of nickel-base alloys. The aim of the present work is to characterize and model the mechanical behaviour of such specimens. Validation of proposed modelling relies mainly on tensile tests carried on specimens equipped with strain gages. One of the striking results is that, for a given displacement rate of the heads of the specimen, a much slower strain rate can be obtained locally in comparison with the strain rate of an equivalent smooth specimen.     

Influence of δ phase precipitation on the stress corrosion cracking resistance of alloy 718 in PWR primary water

The negative influence of δ phase on the intergranular stress corrosion cracking (IGSCC) resistance of alloy 718 is commonly taken for granted. In addition, δ phase formed at low temperature (about 1023 K) do not present the same characteristics than the one formed at higher temperatures (from 1173 to 1273 K). The aim of the present study is then to understand how δ phase precipitation could enhance crack initiation in alloy 718, whatever the form of δ phase is. For that purpose, several heat treatments leading to δ phase precipitation were realized on two alloy 718 heats, one sensitive to IGSCC and the second not. Specific slow strain rate tensile tests carried out on thin tensile specimens in simulated PWR primary medium at 633 K conclusively prove that δ phase has no effect on the intrinsic sensitivity to intergranular crack initiation of tested heats.     

Bayesian Robot Programming

We propose a new method to program robots based on Bayesian inference and learning. It is called BRP for Bayesian Robot Programming. The capacities of this programming method are demonstrated through a succession of increasingly complex experiments. Starting from the learning of simple reactive behaviors, we present instances of behavior combination, sensor fusion, hierarchical behavior composition, situation recognition and temporal sequencing. This series of experiments comprises the steps in the incremental development of a complex robot program. The advantages and drawbacks of BRP are discussed along with these different experiments and summed up as a conclusion. These different robotics programs may be seen as an illustration of probabilistic programming applicable whenever one must deal with problems based on uncertain or incomplete knowledge. The scope of possible applications is obviously much broader than robotics.     

The effect of drawing on memory performance in young children.

In Experiment 1, 32 5- to 6-year-old boys and girls participated in a unique event and were interviewed about that event 1 day later. Half of the children were asked to draw what happened during the event and half were asked to tell what happened. In both conditions, only children's verbal behavior was scored. Children in the draw group were as accurate and reported more information than children in the tell group, especially in response to direct questions. In Experiment 2, 32 5- to 6-year-olds and 32 3- to 4-year-olds participated in the same event used in Experiment 1 and were interviewed 1 month later. The 5- to 6-year-olds in the draw group reported more information than the 5- to 6-year-olds in the tell group after the 1-month delay. Drawing did not, however, increase the amount of information reported by 3- to 4-year-olds. These findings have important theoretical implications for memory development and important practical implications for children's eyewitness testimony. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Leak rate test of personnel airlock for LWR containment subject to pressures and temperatures beyond design

As part of the U.S. Nuclear Regulatory Commission's (USNRC) Containment Integrity Program, a full-size personnel airlock for a nuclear containment building was subjected to conditions simulating a severe accident.The objective of the test was to characterize the performance of an airlock when subjected to conditions that exceeded design. The gasket tested was a “double dog-ear” configuration made from an elastomer known as EPDM E603. The data obtained from this test will be used by SNL as a benchmark for development of analytical methods.Strain, temperature, displacements, pressure, and leak rate data were measured and recorded from over 330 transducers. The test lasted approximately 60 hours. Data were recorded at regular intervals during heating, pressurization and depressurization.The airlock was originally designed for 340°F and 60 psig. The airlock inner door and bulkhead were exposed to a maximum air temperature of approximately 850°F and a maximum air pressure of 300 psig. Two heating and pressurization cycles were planned; one to heat the air to 400°F and pressurize to 300 psig, and the second to heat to 800°F and pressurize to 300 psig. No significant leakage was recorded during these two cycles. A third cycle was added to the test program. The air temperature was increased to approximately 850°F and held at this temperature for nearly 12 hours. Pressure was increased and the inner door seal failed at a pressure of 150.5 psig. The maximum leak rate recorded past the inner door seal was 706 SCFM. The outer door seal did not fail.     

Synthesis and Organo-Catalyzed Ring-Opening of a Six-Membered Heterocycle Combining Phosphonate and Ester Functions

The synthesis of a difunctional P-heterocycle combining phosphonate and ester moieties in a six-membered ring is described. Using trifluoromethane sulfonic acid HOTf as organocatalyst, ring-opening with neopentyl alcohol readily occurs with complete selectivity for O-acyl bond cleavage. In turn, ring-opening polymerization proceeds in a controlled manner when an excess of P-heterocycle is used. Copolymerization with ϵ-caprolactone is also reported and semi-batch conditions are shown to enable regular incorporation of the phosphonate moieties along the polymer chains.     

High-Throughput Strategies for the Design,Discovery, and Analysis of Bismuth-Based Photocatalysts

Bismuth-based nanostructures (BBNs) have attracted extensive research attention due to their tremendous development in the fields of photocatalysis and electro-catalysis. BBNs are considered potential photocatalysts because of their easily tuned electronic properties by changing their chemical composition, surface morphology, crystal structure, and band energies. However, their photocatalytic performance is not satisfactory yet, which limits their use in practical applications. To date, the charge carrier behavior of surface-engineered bismuth-based nanostructured photocatalysts has been under study to harness abundant solar energy for pollutant degradation and water splitting. Therefore, in this review, photocatalytic concepts and surface engineering for improving charge transport and the separation of available photocatalysts are first introduced. Afterward, the different strategies mainly implemented for the improvement of the photocatalytic activity are considered, including different synthetic approaches, the engineering of nanostructures, the influence of phase structure, and the active species produced from heterojunctions. Photocatalytic enhancement via the surface plasmon resonance effect is also examined and the photocatalytic performance of the bismuth-based photocatalytic mechanism is elucidated and discussed in detail, considering the different semiconductor junctions. Based on recent reports, current challenges and future directions for designing and developing bismuth-based nanostructured photocatalysts for enhanced photoactivity and stability are summarized.