Frequency Methods Applied to the Characterization of the Thermophysical Properties of a Granular Material with a Cylindrical Probe

In many fields, such as in the agri-food industry or in the building industry, it is important to be able to monitor the thermophysical properties of granular materials. Regular thermal probes allow for the determination of one or several thermophysical factors. The success of the method used depends in part on the nature of the signal sent, on the type of physical model applied and eventually on the type of probe used and its implantation in the material. Although efficacious for most applications, regular thermal probes do present some limitations. It is the case, for example, when one has to know precisely the thermal contact resistance or the nature of the signal sent. In this article is presented a characterization method based on thermal impedance formalism. This method allows for the determination of the thermal conductivity, the thermal diffusivity, and the contact thermal resistance in one single test. The application of this method requires the use of a specific probe developed to enable measurement of heat flux and temperature at the interface of the probe and the studied material. Its practical application is presented for dry sand.     

A method for measurement of multiple constitutive properties for composite materials

Accurate stress–strain constitutive properties are essential for understanding the complex deformation and failure mechanisms for materials with highly anisotropic mechanical properties. Among such materials, glass-fiber- and carbon-fiber-reinforced polymer–matrix composites play a critical role in advanced structural designs. The large number of different methods and specimen types currently required to generate three-dimensional allowables for structural design slows down the material characterization. Also, some of the material constitutive properties are never measured due to the prohibitive cost of the specimens needed. This work shows that simple short-beam shear (SBS) specimens are well-suited for measurement of multiple constitutive properties for composite materials and that can enable a major shift toward accurate material characterization. The material characterization is based on the digital image correlation (DIC) full-field deformation measurement. Two key elements show advantage of using DIC in the SBS tests. First, tensile, compressive, and shear stress–strain relations are measured in a single experiment. Second, a counter-intuitive feasibility of closed-form stress and modulus models, normally applicable to long beams, is demonstrated for short-beam specimens. The modulus and stress–strain data are presented for glass/epoxy and carbon/epoxy material systems.     

NERC matters: NERC enforcement needs improvements

When the North American Electric Reliability Corporation (NERC) and its regional entities began enforcing mandatory reliability standards, every potential violation, regardless of the potential risk to the Bulk Power System (BPS), was generally prosecuted. Although many of these violations were assessed zero or nominal penalties, the resources expended in their prosecution were substantially the same as those used for the prosecution of higher-risk violations, not only by the regional entity, but also by NERC and registered entities.     

NERC matters: Vexatious PRC-005

North American Electric Reliability Corporation (NERC) reliability standard PRC-005, which pertains to maintenance and testing of generation and transmission Protection Systems, is the “most violated standard of all time.” 1 And notwithstanding NERC's efforts at providing guidance to improve compliance, the standard remains vexatious. Moreover, recent changes to PRC-005 intended to provide clarity might increase the uncertainty as to how best to comply. At a minimum, registered entities will need to commit additional resources to revise their programs to satisfy these new requirements.     

NERC and Enforcement Issues: NERC Provides Best Practices for Effective Procedures

The North American Electric Reliability Corporation (NERC) recently issued a report of its findings after analyzing the auditing procedures of its eight regional entities, related to the disturbance event reporting standards: CIP-001-2a, EOP-004-1, and EOP-004-2. While an auditor must perform the due diligence necessary to have a reasonable assurance that a responsible entity (an entity responsible for compliance with a particular reliability standard) is in compliance with a standard, inevitably different compliance auditing practices are used across the eight regions. Such inconsistency could lead to different results.     

NERC and Enforcement Issues: Self‐Reporting Routine Compliance Violations

The Federal Energy Regulatory Commission (FERC) assessed a $750,000 civil penalty against International Transmission Company and several of its public utility affiliates for failure to obtain FERC approval under Section 203 of the Federal Power Act (FPA) for 20 jurisdictional transactions, which were self‐reported to FERC. The company and its affiliates were also penalized here for failing to make appropriate filings under FPA Section 205 with respect to 174 jurisdictional agreements that were not self‐reported to FERC.     

Polymer-Biologically Active Principle Conjugates Obtained by Esterification of Poly(Vinyl Alcohol)

The paper deals with the study of some polymer-biologically active principle systems characterized by the controlled release of the bioactive component by hydrolyze followed by diffusion. The systems were obtained by coupling the 2-mercapto-benzotiazolyl-acetic acid and N-(m-nitrobenzoyl)-L-methionine on poly(vinyl alcohol) by means of esteric bonds in the presence of diciclohexylcarbodiimide as an activator. The influence of some coupling process parameters on the reaction efficiency was studied, such as the drug/support and activator/support ratios. The coupling products with a maximum content of biologically active compound were characterized by spectral measurements, also as regards the capacity of bioactive compound release under the conditions simulating those within the gastro-intestinal tract. The antibacterial activity of the conjugates against Staphylococcus aureus, Eschrichia coli, Sarcina lutea, and Bacillus subtilis was determined.     

On the energetic balance for the flow of a Maxwell fluid due to a constantly accelerating plate

Dissipation, the power due to the shear stress at the wall and the boundary layer thickness for the motion of a Maxwell fluid, induced by a constantly accelerating plate, are established in exact and approximate forms. The corresponding solutions for Newtonian fluids, performing the same motion, are obtained as limiting cases of our solutions. In comparison with the Newtonian model, the dissipation and the boundary layer thickness decrease.     

Sediment greenhouse gases (methane and carbon dioxide) in the Lobo-Broa Reservoir, São Paulo State, Brazil: Concentrations and diffuse emission fluxes for carbon budget considerations

Carbon gases (methane, CH₄, and carbon dioxide, CO₂) were measured for the first time in sediments of the Lobo‐Broa Reservoir, near São Carlos in São Paulo State, Brazil. It is believed these are the first measurements of this kind in any of the many reservoirs located in Brazil. Even though the Lobo‐Broa Reservoir is classified as oligotrophic, the sediment gas concentrations were exceedingly high, ranging from 0.4–3 mmol L^?1 for CH₄ and 1–9 mmol L^?1 for CO₂. Both gases exceeded their in situ gas saturation values at these shallow water depths (7 m in central basin; 11 m at dam), resulting in numerous sediment bubbles. Organic matter was highly concentrated in the reservoir sediments, averaging 25.5% loss on ignition (LOI) (dam) to 26.9% LOI (central basin) for the 0–12 cm depth interval, with values as high as 29–30% LOI (12% organic carbon) in the surface 0–5 mm layer. The theoretical flux of dissolved pore water carbon gases to the sediment–water interface (SWI) averaged 3.4 mmol L^?1 m^?2 day^?1 CH₄ and 7.3 mmol L^?1 m^?2 day^?1 CO₂ for the surface 0–10 mm. From gas emission measurements at the water surface, it was calculated that 90% of CH₄ is consumed either at the SWI or in the water column, resulting in a loss of 0.31 mmol L^?1 m^?2 day^?1 of CH₄ to the atmosphere. However, only 20% of the total CO₂ gas transported across the water–atmosphere interface (36.3 mmol L^?1 m^?2 day^?1, or 1600 mg CO₂ m^?2 day^?1) was produced in the sediments. The remaining 80% of CO₂ probably comes from other carbon sources. With CH₄ oxidation in the aerobic water column, close to 30% of the carbon gas flux to the atmosphere could be accounted for by gas production of CO₂ and CH₄ in the sediments and their diffuse transport to the water column.     

The Effect of Electroporation of a Lyotroic Liquid Crystal Genistein-Based Formulation in the Recovery of Murine Melanoma Lesions

A lamellar lyotropic liquid crystal genistein-based formulation (LLC-Gen) was prepared in order to increase the aqueous solubility of the lipophilic phytocompound genistein. The formulation was applied locally, in a murine model of melanoma, with or without electroporation. The results demonstrated that, when the formulation was applied by electroporation, the tumors appeared later. During the 21 days of the experiment, the LLC-Gen formulation decreased the tumor volume, the amount of melanin and the degree of erythema, but when electroporation was applied, all these parameters indicated a better prognosis even (lower tumor volume, amount of melanin and degree of erythema). Although hematoxylin–eosin (HE) staining confirmed the above events, application of the LLC-Gen formulation by electroporation did not lead to a significant effect in terms of the serum concentrations of the protein S100B and serum neuron specific enolase (NSE), or the tissue expression of the platelet-derived growth factor receptor β (PDGFRβ) antibody.