Identifying routes and organizational practices for resilient performance: a study in the construction industry

Cognition, Technology & Work - Modern organizations live in a context of political, economic, technological, social and environmental changes for which they need to be prepared to adapt and...     

Dynamics and scaling of explosion cratering in granular media

Granular cratering is a ubiquitous phenomenon occurring in various natural and industrial contexts. Although impact‐induced granular cratering has been extensively studied, fewer experiments have been conducted on granular cratering via low‐energy explosions. Here, we study the dynamics and scaling of explosion granular cratering by injecting short pulses of pressurized air in quasi‐two‐dimensional granular media. Through an analysis of the dynamics of explosion processes at different explosion pressures, explosion durations, and burial depths, we identify two regimes, the bubbling and the eruption regimes, in explosion granular cratering. Our experiments explore the distinctive dynamics and crater morphologies of these regimes and show the energy scaling of the size of explosion craters. We compare high‐energy and low‐energy explosion cratering as well as explosion and impact cratering in terms of their energy scalings. Our work illustrates complex granular flows in explosion cratering and provides new insights into the general scaling of granular cratering processes. © 2017 American Institute of Chemical Engineers AIChE J, 64: 2972–2981, 2018     

Polycarbonate/1‐(2‐hydroxyethyl)‐2,3‐dimethylimidazolium chloride composite membranes and short‐range chain mobility analysis

In this investigation, the incorporation of imidazolium salt, 1‐(2‐hydroxehtyl)‐2,3‐dimethylimidazolium chloride [hydemmim][Cl] within bisphenol A polycarbonate (PC) matrix and the subsequent formation of membranes via casting were studied. Characterizations that aimed to establish structure‐property correlations by Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, dynamic mechanical thermal analysis, and water vapor transport (WVT) were performed. The results indicated that the presence of ionic liquid (IL) within the PC matrix significantly alter the local and macromolecular structure. The thermal stability is increased for all levels of incorporation. The plasticizing and antiplasticizing effects were observed due to the influence of the proportions of IL incorporated and of the cation's substituent chain of this IL. Distinct mechanisms of WVT were also observed in the presence of IL. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45117.     

Cellular localization of cadmium and structural changes in maize plants grown on a cadmium contaminated soil with and without liming

The effects of different concentrations of soil cadmium (0, 1, 3, 5, 10, and 20mgkg(-1)) on growth, structural changes and cadmium cellular localization in leaves of maize plants (Zea mays L.) were investigated in a pot experiment. The results showed that the structural changes observed in maize leaves were not only a response to the Cd-induced stress but also a cellular mechanism to reduce the free Cd(+2) in the cytoplasm. However, this mechanism seems to be efficient only up to a Cd concentration in leaves between 27 and 35mgkg(-1) for soils without and with liming, respectively. The cellular response varied with both the Cd concentration in soil and liming. For limed soil, Cd was preferentially accumulated in the apoplast while for unlimed soils Cd was more evenly distributed into the cells. The ability of Cd accumulation depended on the leaf tissue considered. The apoplast collenchyma presented the highest Cd concentration followed by the endodermis, perycicle, xylem, and epidermis. On the other hand, symplast Cd accumulated mainly in the endodermis, bundle sheath cells, parenchyma, and phloem. Based on the structural changes and growth reduction, the critical toxic concentration of soil Cd to maize plants is between 5 and 10mgkg(-1).     

Evaluation of Tungsten Coil Atomic Emission Spectrometry for the Direct Determination of Al in Tea Infusions and Iced Tea

This work describes the determination of aluminum in tea infusions and iced tea by tungsten coil atomic emission spectrometry (WCAES). The instrumentation is simple, inexpensive, and potentially portable. It uses a tungsten filament extracted from 150 W, 15 V commercially available slide projector light bulbs as electrothermal atomizer. A simple power supply that provides a constant potential is used to heat the coil. Tea infusions were directly analyzed by application of an optimized heating program. In order to avoid matrix interferences, the iced tea samples were diluted with an oxidizing mixture composed of hydrogen peroxide and nitric acid and also analyzed by a tailored heating program. Aluminum was quantified in all samples, and the results were in agreement with those obtained by inductively coupled plasma optical emission spectrometry at a 95 % confidence level. The limit of detection and the relative standard deviation for a solution containing 2.5 mg L^?1 Al (n?=?10) were determined, and the values were 0.09 mg L^?1 and 5.1 %, respectively.     

Antibody labeling of cholesterol/ceramide ordered domains in cell membranes

A monoclonal antibody raised against mixed monolayers of 60:40 mol % cholesterol/C16-ceramide of known structure was used to label cholesterol/ceramide-rich domains in cell membranes. The antibody, Cer-Chol 405F specifically recognizes the mixed crystalline and homogeneous phase in monolayers, but it does not interact with either of the components separately. It interacts differently with mixed monolayers that contain ceramides of different acyl chain length. When used on cells, the antibody labeling is sensitive to changes in cholesterol and ceramide levels, as well as to over-expression of specific ceramides; this is in agreement with the results that were obtained on lipid monolayers. This represents a proof of concept of the applicability of a new approach to the structural characterization of lipid microdomains in cell membranes. The approach consists of raising antibodies that recognize specific structural organizations of lipids in artificial mixtures, characterizing the antibody/ordered domain complexes in vitro, and subsequently using them to detect the presence of the same (or similar) domains in cell membranes.     

Mechanical Properties and Microstructural Characterization of Aged Nickel-based Alloy 625 Weld Metal

Metallurgical and Materials Transactions A - The aim of this work was to evaluate the different phases formed during solidification and after thermal aging of the as-welded 625 nickel-based alloy,...     

Probing the Relationship of Long-Range Order in Nanodomain FeCo Alloys with Ternary Additions Using Neutron Diffraction

The effects of tailoring FeCo alloys with addition of ternary elements Pt, Pd, Mn, Ir, and Re have been investigated. In the composition range of 30 to 70 pct Co, FeCo alloys undergo a continuous order-disorder phase transition at a maximum temperature of 730 °C at the equiatomic composition. The effects of temperature and composition on the degree of long-range order in six alloys (Fe₇₀Co₃₀, Fe₆₇Co₃₀Pt₃, Fe₆₇Co₃₀Pd₃, Fe₆₇Co₃₀Mn₃, Fe₆₇Co₃₀Ir₃, and Fe₆₇Co₃₀Re₃; at. pct) were compared using neutron diffraction. The transition goes along with growing of antiphase domains during the heating process.