Distilling the salient features of natural systems: Commentary on “On the mapping of genotype to phenotype in evolutionary algorithms” by Whigham,Dick and Maclaurin

Here we comment on the article, “On the mapping of genotype to phenotype in evolutionary algorithms”, by Peter A. Whigham, Grant Dick, and James Maclaurin. The authors present a critical view on the use of genotype to phenotype mapping in Evolutionary Algorithms, and how the use of this analogy can be detrimental for problem solving. They examine a grammar-based approach to Genetic Programming (GP), Grammatical Evolution (GE), and highlight properties of GE which are detrimental to effective evolutionary search. Rather than use loose analogies and methaphors, we suggest that a focus should be (and has been in GE and other approaches to GP) on addressing one of the most significant open issues in our field, i.e., What are the sufficient set of features in natural, genetic, evolutionary and developmental systems, which can translate into the most effective computational approaches for program synthesis?     

Emergence of modern scientific discourse in the American continent: knowledge claims in the discovery of Erythronium/Vanadium in Mexico (1802–1832)

In the present paper, we study the discovery of the chemical element number 23, Erythronium/Vanadium (E/V), as an early example of the modern process of validating knowledge claims in México. We examined the published work between 1802 and 1832 of Andrés Manuel del Río (AMR) in the Royal Mining Seminar of México and contrasted the styles of argument and forms of certification between his teaching and experimental writings concerning his claim to the paternity of E/V discovery. We also analyze the respective papers of European authors that replicated, rediscovered and certified AMR’s finding. We use a combination of bibliometric, sociotechnical network and literary critical analysis in order to show that the certification of E/V spawned an emerging mode for producing and validating new knowledge in the American continent and particularly in México. In turn, this approach supports AMR’s claim to the discovery of E/V from the production process of the lead brown ore in Zimapán, México.

     

How to Attain Ultralow Interfacial Tension and Three-Phase Behavior with a Surfactant Formulation for Enhanced Oil Recovery: a Review—Part 3. Practical Procedures to Optimize the Laboratory Research According to the Current State of the Art in Surfactant Mixing

The minimum interfacial tension to be reached in enhanced oil recovery by surfactant flooding implies the attainment of a so-called optimum formulation. Part 1 of the present review showed that this formulation may be described as a numerical correlation between the involved variables defining the oil, the water, the surfactant and the temperature. Since it is unlikely to find a single surfactant matching the crude/brine/T/P system characteristic of a reservoir, a mixture of at least two surfactant species is always used. The scan technique method to test the mixing requires about ten interfacial tension or phase behavior experiments and results in a single data. Hence, the scan experiments have to be repeated many times to find a minimum tension which is low enough, e.g. 0.001 mN/m, for the given crude oil-brine system. Part 2 of this review has shown that there are many formulation variables and thus too many possibilities to easily choose experimental conditions. Since there is no simple method to select two or more surfactant species, the choice is made from partial experience or intuition, and sometimes at random. The laboratory time and cost to reach an appropriate optimum formulation is often excessive. Part 3 of this review shows that by cleverly using a three-surfactant mixture, the experimental work to attain a very low interfacial tension for a given reservoir case can be considerably reduced. It is a matter of using the available information along a proper sequential step by step path toward the optimum.     

A comparison of different approaches for depth profiling of films and coatings by confocal Raman microscopy

We compare and analyze different approaches to perform depth profiling of polymer films and coatings by confocal Raman microscopy (CRM). Data were generated using three methodologies: conventional metallurgical objectives, oil-immersion optics and numerical post processing of the as-measured intensity profiles, via an optimized deconvolution technique adapted to CRM. A series of bi- and multi-layered polymeric films were used as test systems. Strengths and weaknesses of each methodology are evaluated in terms of delivered depth resolution, signal throughput and flexibility. It is shown that the application of regularized deconvolution on data obtained from dry objectives yielded intensity profiles with a quality comparable, in some cases superior, to those obtained with immersion objectives, with the advantage of being totally non-invasive.     

Neoformation of antioxidants in glycation model systems treated under subcritical water extraction conditions

In this work, the possibility of finding newly formed Maillard reaction products produced as a result of the subcritical water extraction (SWE) conditions is explored. Simplified powdered glycation model systems were prepared mixing amino acid (Lys, Arg or Ala) and glucose in a molar ratio 1:4. Samples constituted by glucose or amino acids alone were also prepared as controls. SWE was carried out at room temperature, 100 °C and 200 °C and 100 bar of pressure for 20 min. Different assays were performed in order to determine the extent of glycation by analyzing the decrease of free amino groups and/or the formation of Maillard reaction products (early, advanced and end products). Namely, formation of early colorless Maillard reaction products, Amadori compounds, was detected by ESI-MS; advanced glycation end products (AGEs) were detected by measuring the fluorescence intensity (λ_ex = 360 nm, λ_em = 460 nm) while end brown products were detected by reading the absorbance at 360 and 420 nm. Besides, the antioxidant capacity of the aqueous extracts was determined by using ABTS and ORAC_FL assays. Results obtained indicated the occurrence of the Maillard reaction under our specific extraction conditions. Early, advanced and end products were detected in the samples. Caramelization of sugar also occurred. As expected, the extent of the non-enzymatic browning depended on the intensity of the thermal treatment. Additionally, data on antioxidant activity suggested the formation of neoantioxidants. These compounds were predominantly formed at 200 °C. In conclusion, this report demonstrates the formation of antioxidant compounds in simplified glycation model systems under SWE conditions.     

碎裂的城市塞维利亚 对1992年世博后的思考

位于欧洲南部中等规模的城市塞维利亚曾分别在1929年与1992年举办过两次重要的国际性博览会,博览会不仅塑造了当下的城市形状,且通过加强通信设施与基础建设转变了城市与整个区域的关系。作为城市发展的捷径,这些大事件能加快发展并有机会通过连贯统一的提案重塑城市,避免长期通用的总体规划带来一系列问题。塞维利亚面对一条需要恢复水体环境的河流,并将成为新的城市节点。然而经过20年,世博会场址仍然与城市其他部分相隔离。该区域城市功能的设置缺失居住和商业,使其置于深度破碎的境地;被包裹的簇团必然将城市区域撕裂开来。这里是碎裂的城市。     

Creep study on alumina and alumina/SWCNT nanocomposites

Alumina and alumina/SWCNT nanocomposites have been sintered by spark plasma sintering, obtaining relative densities higher than 99%. Microstuctural characterization revealed a grain microstructure in the submicron range, where alumina/SWCNT nanocomposites exhibited a good CNTs dispersion thought the ceramic matrix. Creep experiments performed in both materials showed a similar mechanical behavior, where the addition of CNTs seems to have a negligible effect on the strain rate, in contrast to results reported by other authors. Grain boundary sliding accommodated by lattice diffusion has been identified as the high temperature deformation mechanisms in both samples, alumina and alumina/SWCNT nanocomposites. We have discussed about the role of CNTs influence on the plasticity of these composites.     

The regeneration of field-spent granular-activated carbons.

The thermal regeneration of field-spent granular-activated carbons (GAC) is being increasingly adopted as a cost-effective alternative to disposal. The success of this practice requires the adjustment of process conditions to maximise the recovery of the original carbon characteristics while minimising carbon loss. This paper describes an investigation into the regeneration of several field-spent GAC representative of those typically generated by the drinking water treatment industry. The carbons were initially investigated for their ash contents and inorganic compositions in order to determine the accumulation of metallic species that affect the regeneration process. Regeneration was conducted in steam at 800 degrees C over reaction times between 0 and 60 min in order to achieve different degrees of carbon gasification. Weight losses were determined for each condition and the resulting carbons characterised for their apparent density, porosity, surface area and aqueous adsorption characteristics. Results showed that spent carbons recovered most of their adsorption characteristics when heated to 800 degrees C under inert conditions. Steam gasification in the range of 5-10 wt% burn-off had some positive effects on the characteristics of the spent carbons which were in most cases counteracted by a reduction in the carbon yield. Steam gasification in excess of 15 wt% burn-off caused a rapid increase in the carbon mesoporosity but a significant deterioration in the carbon microporosity, BET surface area and adsorption capacity for organic species of small molecular size.