Landfill leachate biological treatment: perspective for the aerobic granular sludge technology.

Landfill leachates are high-strength complex mixtures containing dissolved organic matter, ammonia, heavy metals, and sulfur species, among others. The problem of leachate treatment has subsisted for some time, but an efficient and cost-effective universal solution capable of ensuring environmental resources protection has not been found. Aerobic granular sludge (AGS) has been considered a promising technology for biological wastewater treatment in recent years. Granules' layered structure, with an aerobic outer layer and an anaerobic/anoxic core, enables the presence of diverse microbial populations without the need for support media, allowing simultaneous removal of different pollutants in a single unit. Besides, its strong and compact arrangement provides higher tolerance to toxic pollutants and the ability to withstand large load fluctuations. Furthermore, its good that settling properties allow high biomass retention and better sludge separation. Nevertheless, AGS-related research has focused on carbon-nitrogen-phosphorus removal, mainly from sanitary sewage. This review aims to summarize and analyze the main findings and problems reported in the literature regarding AGS application to landfill leachate treatment and identify the knowledge gaps for future applications.

Microstructure Effect of Heat Input on Ballistic Performance of Welded High Strength Armor Steel.

The effect of two different heat inputs, 1.2 and 0.8 kJ/ mg, on the microstructure associated with a welded high hardness armor (HHA) steel was investigated by ballistic tests. A novel way of comparing the ballistic performance between fusion zone (FZ), heat-affected zone (HAZ), and base metal (BM) of the HHA joint plate was applied by using results of the limit velocity V50. These results of V50 were combined with those of ballistic absorbed impact energy, microhardness, and Charpy and tensile strength revealing that the higher ballistic performance was attained for the lower heat input. Indeed, the lower heat input was associated with a superior performance of the HAZ, by reaching a V50 projectile limit velocity of 668 m/s, as compared to V50 of 622 m/s for higher heat input as well as to both FZ and BM, with 556 and 567 m/s, respectively. Another relevant result, which is for the first time disclosed, refers to the comparative lower microhardness of the HAZ (445 HV) vs. BM (503 HV), in spite of the HAZ superior ballistic performance. This apparent contradiction is attributed to the HAZ bainitic microstructure with a relatively greater toughness, which was found more determinant for the ballistic resistance than the harder microstructure of the BM tempered martensite.

Rehabilitación vocal fisiológica con ejercicios de tracto vocal semiocluido / Physiologic voice rehabilitation with semi-occluded vocal tract exercises

Introducción. Los ejercicios de tracto vocal semiocluido (ETVSO) son herramien-tas utilizadas en la rehabilitación fisiológica de la voz. Los ETVSO son ejercicios vocales producidos por la semioclusión del tracto vocal, a través de una serie de posturas que buscan alargar y/o ocluir el tracto vocal, generando un cambio en el patrón vibratorio de los pliegues vocales, grado de aducción y el patrón respiratorio. Los ETVSO pueden dividirse, según el tipo de semioclusión, en sostenida, transitoria y oscilatoria, así como en ejercicios de mayor resistencia a menor resistencia.Objetivo. Describir los diferentes tipos de ejercicios de tracto vocal semiocluido, el tipo de semioclusión, el grado de resistencia y sus efectos en los pliegues vocales, patrón respiratorio y configuración del tracto vocal. Metodología. Se realizó una revisión de la literatura en las bases de datos PubMed, Medline y Science Direct, usando los siguientes términos: "Semi-Occluded Vocal Tract Postures", "tract vocal semiocclude" y "ejercicios de tracto vocal semiocluido". Se utilizaron operadores booleanos "AND" y "OR" para especificar la búsqueda.Resultados. Los beneficios de estos ejercicios impactan positivamente en variables aerodinámicas, en la función glótica y en la configuración del tracto vocal. Conclusiones. Los ejercicios de tracto vocal semiocluido son una familia de ejerci-cios vocales producidos por semioclusión sostenida, transitoria y oscilatoria del tracto vocal, a través de una serie de posturas que buscan alargar y/o ocluir el tracto vocal, cuyos beneficios impactan positivamente los pliegues vocales y el tracto vocal

Introduction. Semi-occluded vocal tract exercises (SOVTE) are tools used in physiologic voice rehabilitation. Semi-occluded vocal tract exercises are vocal exer-cises produced by the semi-occlusion of the vocal tract through a series of postures that seek to lengthen and/or occlude the vocal tract, generating a change in the vibratory pattern of vocal folds, degree of vocal folds adduction, and the respira-tory pattern. SOVTE can be divided, according to the type of semi-occlusion, into sustained, transient and oscillatory, as well as exercises with high and low degree of airflow resistance.Objective. To describe the different types of semi-occluded vocal tract exercises, the type of semi-occlusion, the type of resistance, and their effects on the vocal folds, respiratory pattern, and configuration of the vocal tract.Methodology. A literature review was performed in the PubMed, Medline, and Science Direct databases, using the following terms: "Semi-occluded vocal tract pos-tures", "Semi-occluded vocal tract" and "Semi-occluded vocal tract exercises". Boo-lean operators "AND" and "OR" were used to specify the search.Results. The benefits of these exercises positively impact aerodynamic variables, glottal function, and configuration of the vocal tract.Conclusions. The semi-occluded vocal tract exercises are a family of vocal exerci-ses produced by the sustained, transitory, and oscillatory semi-occlusion of the vocal tract, through a series of postures that seek to lengthen and/or occlude the vocal tract, whose benefits positively impact on vocal folds and vocal tract.

Effects of Plastic Waste on the Heat-Induced Spalling Performance and Mechanical Properties of High Strength Concrete.

This paper investigates a potential application of hard-to-recycle plastic waste as polymeric addition in high strength concrete, with a focus on the potential to mitigate heat-induced concrete spalling and the consequent effects on the mechanical properties. The waste corresponds to soft and hard plastic, including household polymers vastly disposed of in landfills, although technically recyclable. Mechanical and physical properties, cracking, mass loss, and the occurrence of spalling were assessed in high strength concrete samples produced with either plastic waste or polypropylene fibers after 2-h exposure to 600 °C. The analysis was supported by Scanning Electron Microscopy and X-Ray Computed Tomography images. The plastic waste is composed of different polymers with a thermal degradation between 250 to 500 °C. Polypropylene (PP) fibers and plastic waste dispersed in concrete have proved to play an essential role in mitigating heat-induced concrete spalling, contributing to the release of internal pressure after the polymer melting. The different morphology of plastic waste and polypropylene fibers leads to distinct mechanisms of action. While the vapor pressure dissipation network originated by polypropylene fibers is related to the formation of continuous channels, the plastic waste seems to cause discontinuous reservoirs and fewer damages into the concrete matrix. The incorporation of plastic waste improved heat-induced concrete spalling performance. While 6 kg/m3 of plastic increased the mechanical performance after exposure to high temperature, the incorporation of 3 kg/m3 resulted in mechanical properties comparable to the reference concrete.

A self-sustaining high-strength wastewater treatment system using solar-bio-hybrid power generation.

This study focuses on system analysis of a self-sustaining high-strength wastewater treatment concept combining solar technologies, anaerobic digestion, and aerobic treatment to reclaim water. A solar bio-hybrid power generation unit was adopted to power the wastewater treatment. Concentrated solar power (CSP) and photovoltaics (PV) were combined with biogas energy from anaerobic digestion. Biogas is also used to store the extra energy generated by the hybrid power unit and ensure stable and continuous wastewater treatment. It was determined from the energy balance analysis that the PV-bio hybrid power unit is the preferred energy unit to realize the self-sustaining high-strength wastewater treatment. With short-term solar energy storage, the PV-bio-hybrid power unit in Phoenix, AZ requires solar collection area (4032m2) and biogas storage (35m3), while the same unit in Lansing, MI needs bigger solar collection area and biogas storage (5821m2 and 105m3, respectively) due to the cold climate.

Implantes de titânio comercialmente puro com alta resistência mecânica para aplicações em Odontologia / High-strength, commercially pure titanium implants for dental applications

O titânio e as suas ligas são amplamente utilizados na fabricação de implantes dentários, face a sua alta resistência à corrosão e à biocompatibilidade. No entanto, o titânio comercialmente puro (Ti cp) e a liga Ti-6Al-4V (Ti G5) têm limitações para aplicações biomédicas. A grande diferença entre os módulos de elasticidade do Ti e osso leva à transmissão indevida de forças na interface osso/implante, induzindo a ocorrência de um fenômeno denominado stress shielding. Outra limitação do Ti cp é sua baixa resistência mecânica, o que dificulta a fabricação de implantes osseointegráveis com paredes finas. A limitação do Ti G5 está associada à libertação de ions de alumínio e vanádio, os quais são tóxicos. O objetivo deste trabalho foi comparar as propriedades mecânicas e a morfologia de um novo Ti cp grau 4 (Ti G4 Hard) com o Ti cp convencional e o Ti G5. Os resultados dos ensaios mecânicos demonstraram que a resistência à tração do Ti G4 Hard é superior ao Ti cp 2, 4 e 5. A análise por microscopia eletrônica de varredura mostrou que cp Ti G4 Hard após tratamento de superfície tem características morfológicas melhores do que o Ti cp convencional e o Ti G5...

Titanium and its alloys are widely used in dental implants because they have high corrosion resistance and adequate biocompatibility. However, commercially pure titanium (cp Ti) and Ti-6Al-4V (Ti G5) have limitations for biomedical applications. The large difference between the modulus of elasticity of Ti and bone leads to improper transmission of forces in the bone-implant interface, a phenomenon called “stress shielding”. Another limitation of cp Ti is a low tensile strength, which reduces the possibility to manufacture small implants with thin walls. The limitation of Ti G5 is the release of aluminum and vanadium ions, which are toxic. The objective of this work is to compare the properties of modified cp Ti Grade 4 (Ti G4 Hard) with those of conventional cp Ti and Ti G5. The results of the mechanical tests showed that the Ti G4 Hard tensile strength is higher than for cp Ti 2, 4 and 5. Scanning electron microscopy analysis showed that cp Ti G4 Hard after surface treating has better morphological features than conventional cp Ti and Ti G5...