The effects of porosity,asphalt content and fiberglass incorporation on the tensile strength and resilient modulus of asphalt concrete blends

Asphalt concrete is the prevailing material used for road surface construction. Its adequate characteristics in providing stability, durability and driving safety are controlled by complex interactions between its components. Thus, it is important to estimate the sensitivity of asphalt concrete mechanical properties as a function of its volumetrics. For this study, different combinations between asphalt content (3.5, 5 and 7.5%) and porosity values (above 4%) were used in order to disassociate these properties. The influence of mixing in fiberglass (0.5%) was also analyzed. It was found that porosity is significantly more relevant than the asphalt content in the prediction of tensile strength and resilient modulus of fiber-free asphalt concretes. In fiber-reinforced mixtures, the mechanical properties are improved by increasing the asphalt content, which suggests a better bonding between fibers and aggregates. For both cases, decreasing porosity is beneficial. By grouping both sets of results, it was possible to create a unique theoretical curve for both the tensile strength (q_t) and the resilient modulus (RM). The RM/q_t ratio was 5800 for the fiber-free group, and 3900 for the fiber-reinforced group - suggesting a better fatigue life indicator for asphalt concretes when fibers are added.     

Use of electronic nose and trained sensory panel in the evaluation of tomato quality

In this paper the performances of an electronic nose based on metalloporphyrin‐coated quartz microbalance sensors and of an experienced panel of seven human assessors in the evaluation of gases derived from degradation reactions in tomatoes are presented and discussed. The performances are measured in terms of the capability of both systems to distinguish between samples of different quality coming from conventional and organic production systems. The study deals with the application of pattern recognition techniques based on either multivariate statistical methods (PCA, GPA) or artificial neural networks using a self‐organising map (SOM). The response pattern of the sensor array and the sensory data are analysed and compared using these methods. Similarities in the classification of the data by electronic nose and human sensory profiling are found. © 2000 Society of Chemical Industry     

Sustainability assessment of bio-ethanol production in Brazil considering land use change,GHG emissions and socio-economic aspects

Three sustainability aspects of bioethanol production in Brazil were considered in this paper. Results show that the recent expansion of sugarcane has mostly occurred at the expense of pasturelands and other temporary crops, and that the hypothesis of induced deforestation is not confirmed. Avoided greenhouse gas emissions due to the use of anhydrous ethanol blended with gasoline in Brazil (E25) were estimated as 78%, while this figure would be 70% in case of its use in Europe (E10). Conversely, considering the direct impacts of land use change, the avoided emissions (e.g., ethanol consumed in Europe) would vary from −2.2% (i.e., emissions slightly higher than gasoline) to 164.8% (a remarkable carbon capture effect) depending on the management practices employed previous to land use change and also along sugarcane cropping. In addition, it was shown that where the bulk of sugarcane production takes place, in state of São Paulo, positive socio-economic aspects are observed. The general conclusion is that a significant share of ethanol production in Brazil can be considered sustainable, in particular regarding the three aspects assessed. However, as production conditions are extremely heterogeneous, a generalization of results is not possible.     

Effect of process parameters and composition on mechanical,thermal, and morphological properties of polypropylene/sawdust composites

Polypropylene/sawdust composites have been prepared according to a statistical experimental design, with varying sawdust and compatibilizer (maleic anhydride grafted PP) concentrations. To investigate process conditions, composites were first extruded in a twin screw extruder coupled to a Haake torque rheometer, without degassing, and then reextruded in a Werner Pfleiderer twin screw extruder, with two degassing zones. Process conditions were analyzed according to statistical techniques. Effect of the variables on mechanical properties was assessed through flexural modulus, tensile strength, and percent elongation at break and morphology was assessed by scanning electron microscopy. Comparison between the extruded and reextruded compounds indicated the need to reduce moisture, prior to and during processing, as well as the need of effective mixing of the compounds. Sawdust concentration showed to be the variable which affected most all properties assessed. Increase in sawdust concentration resulted in increased composite stiffness. The presence of the compatibilizer caused a slight increase in tensile strength and reduction in percent elongation at break, indicating improved adhesion at the PP/sawdust interface. The reprocessed compounds were also analyzed by differential scanning calorimetry. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Incremental testing of finite state machines

The automatic generation of test suites for systems modelled as finite state machines (FSMs) is an important problem that impacts several critical applications. Known methods that automatically generate tests for FSMs, specially the W‐method and some derivations, strongly assume that the number of system states is small. If the overall number of states in the FSM specification is relatively large, such methods become difficult to use. However, often in practice, a system is defined as a combination of several subsystems, with the latter already independently designed, developed and tested. In this paper, we define the concept of combined FSMs and introduce a new method to test modular compositions of FSMs. This method allows for a new incremental testing strategy that turns the testing of new systems into a much more scalable process. As an example, we present an infinite family of naturally occurring FSM models for which our method produces exponentially more compact test suites than the W‐method. Copyright © 2012 John Wiley & Sons, Ltd.     

Mobilisation of bacteria in a fine-grained residual soil by electrophoresis

An investigation of electrokinetic bacterial mobilisation in a residual soil from gneiss is presented here. The experimental program aimed at assessing the efficacy of electrophoresis against the electro-osmotic flow to transport endospores of Bacillus subtilis LBBMA 155 and nitrogen-starved cells of Pseudomonas sp. LBBMA 81. Electrokinesis was performed on a low hydraulic reconstituted clayey soil column submitted to a 5mA electrical current for 24h. Cells were coccoid-shaped and characterised as possessing low surface hydrophobicity and less than 1microm in diameter. Distribution coefficient for B. subtilis in the soil was between 16.8 and 19.9 times higher than that for Pseudomonas sp. Distribution coefficient for B. subtilis between eluate and anionic exchange column was 11.8 times higher than that for Pseudomonas sp. After the electrokinesis, it was shown that cells and endospores were distributed hyperbolically through the soil probe and moved against the electro-osmotic flow; however, endospores were transported throughout all soil core and starved cells only till half of its length. The higher transport efficiency of B. subtilis endospores was attributed to their higher negative charge on cell surface. These results demonstrate that electrokinesis can be used for bacteria transport in soils with low hydraulic conductivity, even against the electro-osmotic flow.     

Structural and optical properties of pillared Eu3+-containing layered double hydroxides intercalated by 2- to 12-carbon aliphatic dicarboxylates

While the versatile composition of layered double hydroxides(LDHs)allows the introduction of almost any polyvalent cation in their structure,the exchangeable negatively charged ions intercalated between the plates increase their vast range of functionalities.Here we report on the preparation and optical properties of pillared Eu³⁺-substituted ZnAl LDHs intercalated by aliphatic dicarboxylates:-OOC-(CH₂)_n-2-COO-.The basal distance in these materials is dependent on the size and packing of the intercalated anions.By varying the number(n)of carbon atoms in the aliphatic chain from 2 to 12,the interlayer gallery of these ZnAlEu LDHs is considerably expanded from 0.9 to 2.1 nm.In the interlayer gallery,the aliphatic dicarboxylates form a monolayer,with the aliphatic chain inclined by an angleα≈63°with the hydroxide layers.The carbon atom in the COO-group is 0.43 nm far from the metal plane,showing that these carboxylates are not grafted in the brucite-like layers.These LDHs are thermally stable up to around 150℃,after which dehydroxylation of the hydroxide layers is observed.The Judd-Ofelt intensity parameters were obtained and compared to the Eu³⁺-containing complexes with the same ligand series indicating a more symmetrical and less polarizable chemical environment around the rare earth ion.     

Biomass energy in Brazil : Past activities and perspectives

Historically, biomass has provided a large share of Brazil's energy supply. Despite its relevance, the success of some biomass programs has been constrained by short-term priorities to the detriment of long-term policies. The potential of biomass will only be accomplished if further activities are focused on sustainability in a broader sense. Arnaldo Walter, State University of Campinas, Brazil assesses bioenergy use in the country, highlighting past programs, activities and barriers to accomplishing future goals.     

Optimization of single mode fibre sensors to detect organic vapours

The construction of single mode optical fibre (SMF) sensors to handle with volatile organic compounds (VOCs), has been optimized to operate at the third telecommunication window (1550 nm). The main motivation is to take advantage of the photonic devices used in telecommunication systems that makes easier sensors multiplexing. Moreover, the low transmission attenuation at that wavelength offers the possibility of remote sensing. The sensing materials used suffer reversible structural alterations in the presence of VOC, such as colour change, which are detectable with a photonic system. Following the Electrostatic Self Assembly method (ESAm), a nanostructure is constructed onto cleaved ended SMF, which is doped with a sensing material. The fabrication of this type of sensors was focused on multimode fibres (MMF) and in the visible spectral range (VIS) so far. The implementation has been adapted to SMF and to operate around 1550 nm, specifically, by easing the adsorption of the VOCs molecules. It has been observed that the sensing material affects the morphology of the nanostructures as well and so, to the sensors response. The devices implemented show a potential use in the identification of single and complex mixtures of VOCs.     

Improvement of the mechanical and aesthetic properties of a coating by inkjet technology

Different amounts of ink, made up almost entirely of a frit that devitrified abundant small crystals of anorthoclase, were applied by inkjet printing onto a traditional unfired glaze substrate. The rheological properties of the ink and porous texture of the unfired glaze substrate were characterized. The fired coatings were analyzed by SEM–EDX to determine the elemental composition at different surface depths, and their microstructure was observed. The results confirmed the validity of the ink penetration model, developed in a previous study, for describing the composition profile in inkjet coatings as a function of the applied amount of ink and pore size and volume in the unfired glaze substrate relative to average ink particle size. Microhardness and indentation modulus of the fired glaze substrate without an ink application and of the fired ink-containing coatings were determined. The values of these properties were verified to fit a Weibull distribution function. The coatings containing an ink application at 400 and 600 dots per inch (dpi), respectively, displayed the best mechanical behavior. The study confirmed that inkjet printing a suspension with appropriate physico-chemical characteristics onto an unfired glaze substrate substantially improved the aesthetic characteristics and mechanical properties of the resulting fired coating.