RSM optimization of the catalytic wet peroxide oxidation of methyl orange and correlation with major intermediates and by-products

Statistical response surface methodology (RSM) was used to optimize the main parameters of the CWPO reaction in the catalytic degradation of methyl orange (MO) in a 1.5 L semi-batch reactor. Studied experimental variables were: (i) catalyst’s concentration, (ii) dose of hydrogen peroxide and (iii) reaction time; Non-controllable variables were: starting pH, Temperature and initial [MO] loading (as Total Organic Carbon - TOC)

Degradación de naranja de metilo mediante la tecnología PCFH activada con un catalizador Al-Fe/PILC

Entre los procesos de oxidación avanzada (POAs), la Peroxidación Catalítica en Fase Húmeda (PCFH) activada con un catalizador de tipo Al/Fe-PILC ha demostrado un enorme potencial para la depuración de compuestos orgánicos tóxicos disueltos en agua (Figura 1) [1]. Por otra parte, recientes estudios han demostrado que la Materia Orgánica Natural (MON) en las fuentes de abastecimiento, está generando serios problemas en los sistemas de tratamiento para la producción de agua potable [2]. Sin embargo, dado que la estructura de la MON es bastante compleja, con una significativa contribución de fenoles y aminas aromáticas, los colorantes diazoicos como el naranja de metilo (NM) pueden servir como moléculas modelo para anticipar el comportamiento de la fracción nitrogenada presente en la MON ante la degradación vía POAs. De acuerdo a lo anterior, en el presente trabajo se reporta la optimización simultánea de los principales parámetros de la degradación PCFH de naranja de metilo (NM) en medio acuoso, empleando un diseño estadístico de experimentos central compuesto, seguido de análisis por superficies multi-respuesta (MSR). Durante el proceso se maximizaron las respuestas: mineralización de NM (eliminación de COD), decoloración (UV-Vis), fracción de peróxido reaccionada (UV-Vis) y eliminación de nitrógeno total (NT) combinadas en una función deseabilidad. También se siguieron los principales intermediarios y subproductos de la oxidación mediante HPLC/DAD y GC/FI

Development of low-pH cementitious materials for HLRW repositories. Resistance against ground waters aggression

One of the most accepted engineering construction concepts of underground repositories for high radioactive waste considers the use of low-pH cementitious materials. This paper deals with the design of those based on Ordinary Portland Cements with high contents of silica fume and/or fly ashes that modify most of the concrete “standard” properties, the pore fluid composition and the microstructure of the hydrated products. Their resistance to long-term groundwater aggression is also evaluated. The results show that the use of OPC cement binders with high silica content produces low-pH pore waters and the microstructure of these cement pastes is different from the conventional OPC ones, generating C–S–H gels with lower CaO/SiO2 ratios that possibly bind alkali ions. Leaching tests show a good resistance of low-pH concretes against groundwater aggression although an altered front can be observe

Presence of Adult Companion Goats Favors the Rumen Microbial and Functional Development in Artificially Reared Kids

Newborn dairy ruminants are usually separated from their dams after birth and fed on milk replacer. This lack of contact with adult animals may hinder the rumen microbiological and physiological development. This study evaluates the effects of rearing newborn goat kids in contact with adult companions on the rumen development. Thirty-two newborn goat kids were randomly allocated to two experimental groups which were reared either in the absence (CTL) or in the presence of non-lactating adult goats (CMP) and weaned at 7 weeks of age. Blood and rumen samples were taken at 5, 7, and 9 weeks of age to evaluate blood metabolites and rumen microbial fermentation. Next-generation sequencing was carried out on rumen samples collected at 7 weeks of age. Results showed that CTL kids lacked rumen protozoa, whereas CMP kids had an abundant and complex protozoal community as well as higher methanogen abundance which positively correlated with the body weight and blood beta-hydroxybutyrate as indicators of the physiological development. CMP kids also had a more diverse bacterial community (+132 ASVs) and a different structure of the bacterial and methanogen communities than CTL kids. The core rumen bacterial community in CMP animals had 53 more ASVs than that of CTL animals. Furthermore, the number of ASVs shared with the adult companions was over 4-fold higher in CMP kids than in CTL kids. Greater levels of early rumen colonizers Proteobacteria and Spirochaetes were found in CTL kids, while CMP kids had higher levels of Bacteroidetes and other less abundant taxa (Veillonellaceae, Cyanobacteria, and Selenomonas). These findings suggest that the presence of adult companions facilitated the rumen microbial development prior to weaning. This accelerated microbial development had no effect on the animal growth, but CMP animals presented higher rumen pH and butyrate (+45%) and ammonia concentrations than CTL kids, suggesting higher fibrolytic and proteolytic activities. CMP kids also had higher blood beta-hydroxybutyrate (+79%) and lower blood glucose concentrations (-23%) at weaning, indicating an earlier metabolic development which could favor the transition from pre-ruminant to ruminant after the weaning process. Further research is needed to determine the effects of this intervention in more challenging farm conditions

Physical mapping of ribosomal DNA and genome size in diploid and polyploid North African Calligonum species (Polygonaceae).

Most Calligonum species are desert plants, characteristic of the Saharan bioclimatic region. All species karyologically analyzed until present have the basic chromosome number x = 9 and comprise diploids, triploids and tetraploids. The Tunisian flora comprises diploid Calligonum arich and C. azel, of restricted distribution, and the tetraploid C. comosum with wider distribution. Analyses of their karyotypes and polyploidisation-linked rDNA changes by orcein staining, fluorochrome banding with chromomycin A3 and fluorescent in situ hybridisation with 5S and 26S ribosomal DNA probes have been performed. We report the chromosome number for Calligonum arich (2n = 18) as well as the diploid level for C. comosum for the first time. Chromosome counts have also verified the earlier described tetraploid cytotype (2n = 36) of C. comosum. A general pattern of six GC-rich bands as well as two 35S sites and four 5S sites is described for Calligonum species at the diploid level although there is intraspecific variation regarding the site number in a second type of C. comosum, with one pair of 35S rDNA sites and two pairs of 5S rDNA sites. The tetraploid cytotype of C. comosum has undergone locus loss and genome downsizing. Genome size assessments confirmed previous data. Nonetheless, statistically significant differences were found depending on the type of tissue used for estimation. Measurements from seeds had always larger values than from leaves. The presence of cytosolic compounds in leaves, interfering with DNA staining, is discussed as a possible cause of the differences

Recent Technological Developments on LGAD and iLGAD Detectors for Tracking and Timing Applications

This paper reports the last technological development on the Low Gain Avalanche Detector (LGAD) and introduces a new architecture of these detectors called inverse-LGAD (iLGAD). Both approaches are based on the standard Avalanche Photo Diodes (APD) concept, commonly used in optical and X-ray detection applications, including an internal multiplication of the charge generated by radiation. The multiplication is inherent to the basic n++-p+-p structure, where the doping profile of the p+ layer is optimized to achieve high field and high impact ionization at the junction. The LGAD structures are optimized for applications such as tracking or timing detectors for high energy physics experiments or medical applications where time resolution lower than 30 ps is required. Detailed TCAD device simulations together with the electrical and charge collection measurements are presented through this work.Comment: Keywords: silicon detectors, avalanche multiplication, timing detectors, tracking detectors. 8 pages. 8 Figure