Oxygen control and improved denitrification efficiency by means of a post-anoxic reactor

The presence of dissolved oxygen (DO) in biological denitrification reactors determines inhibition effects on the denitrification rate. The article shows the results of an experimental study to control the DO concentration in the pre-denitrification stage by a post-anoxic reactor. The results demonstrate that the post-anoxic reactor is very effective in improving the nitrogen removal efficiency because it causes a considerable reduction of the DO content in the mixed liquor recycle sent to the pre-denitrification reactor. This reduction is influenced by both the retention time and the F:M ratio (referred to the denitrification and the oxidation-nitrification volume). In fact, a retention time and a F:M ratio equal to 1.5 h and 0.130 kgBOD5 kgMLVSS−1·day−1, respectively, allow to limit DO in the post-anoxic reactor at 0.31 mgO2·L−1. Such concentration determines a DO concentration of 0.11 mgO2·L−1 in the pre-denitrification reactor and, consequently, a denitrification efficiency of 91%. Moreover, the contribution of the endogenous denitrification to the whole denitrification efficiency was found negligible. The paper contributes to the progress in nitrogen removal from sewage, a fundamental issue for a sustainable management of water resources

Occupations at risk and organizational well-being: an empirical test of a Job Insecurity Integrated Model

One of the more visible effects of the societal changes is the increased feelings of uncertainty in the workforce. In fact, job insecurity represents a crucial occupational risk factor and a major job stressor that has negative consequences on both organizational well-being and individual health. Many studies have focused on the consequences about the fear and the perception of losing the job as a whole (called quantitative job insecurity), while more recently research has begun to examine more extensively the worries and the perceptions of losing valued job features (called qualitative job insecurity). The vast majority of the studies, however, have investigated the effects of quantitative and qualitative job insecurity separately. In this paper, we proposed the Job Insecurity Integrated Model aimed to examine the effects of quantitative job insecurity and qualitative job insecurity on their short-term and long-term outcomes. This model was empirically tested in two independent studies, hypothesizing that qualitative job insecurity mediated the effects of quantitative job insecurity on different outcomes, such as work engagement and organizational identification (Study 1), and job satisfaction, commitment, psychological stress and turnover intention (Study 2). Study 1 was conducted on 329 employees in private firms, while Study 2 on 278 employees in both public sector and private firms. Results robustly showed that qualitative job insecurity totally mediated the effects of quantitative on all the considered outcomes. By showing that the effects of quantitative job insecurity on its outcomes passed through qualitative job insecurity, the Job Insecurity Integrated Model contributes to clarifying previous findings in job insecurity research and puts forward a framework that could profitably produce new investigations with important theoretical and practical implications

Valorizzazione della Torre: un Museo della Scarpa e una Scuola Calzaturiera nel Paese dei Calzolai

La tesi di laurea elaborata ha come oggetto Villa Torlonia, chiamata anche “ la Torre” , un complesso edilizio risalente al Settecento. Il lavoro effettuato ha compreso prima di tutto uno studio della storia della Torre, l’evoluzione e il rapporto con il suo contesto. È seguita poi un’analisi del complesso, effettuata dal punto di vista sia della consistenza che dello stato di conservazione, per poi studiare l’insieme di interventi che l’hanno caratterizzata e che le hanno conferito l’attuale aspetto.Si tratta di opere di consolidamento, di recupero e di ripristino che hanno occupato un’epoca che va dagli ultimi vent’anni del Novecento fino ad ora. Solo dopo questa fase di studio e di ricerca si è passati ad elaborare un programma di riutilizzo della Villa, che occupa il quinto capitolo della Tesi. L’idea progettuale sviluppata parte dall'intento di valorizzare questo complesso edilizio che, essendo di proprietà comunale, è spesso oggetto di manifestazioni culturali. La grande corte esterna, il piano terra del corpo centrale ed i vecchi magazzini al piano interrato sono oggigiorno sede di incontri di moda e di momenti espositivi temporanei, molti dei quali legati alla produzione calzaturiera locale. San Mauro Pascoli ospita infatti le sede di alcune delle più note marche dell'alta moda calzaturiera e la sua economia così come la sua storia, è legata a questa attività che da più di un secolo rappresenta una vera e propria attrattiva locale. Il tipo di intervento che si viene a delineare parte quindi dal voler privilegiare questa tradizione del luogo, pertanto il progetto prevede l’inserimento di un Museo della scarpa e lo spostamento della scuola calzaturiera CERCAL, al fine di rendere Villa Torlonia un centro di attrazione turistica

Application Of A Decision Support System For The SustainablePlanning Of Rio Pojuca Basin (Bahia, Brazil) Water Resources

The paper presents the structure and the application of a Decision Support System (DSS) to Pojuca River watershed placed in the Northeast Region of Brazil (Bahia State). It is composed of surface-water quality models (total phosphorus, BOD, dissolved oxygen concentration and thermo-tolerant coliform bacteria pollution). A model evaluates the riverine microhabitat applying autochthonous fish species habitat suitability indexes (water depth, velocity, substrate and dissolved oxygen) valuated by local ichthyologists. Surface-water quality and microhabitat models are based on a hydrologic and hydraulic model. Models have been calibrated and validated using discharge and water quality measurements collected during a 1.5-year period of monitoring. Output data are available on a spreadsheet and ready to be spatially analyzed in a GIS software. We show how DSS can help the decision-making process to achieve the sustainable development of the basin, considering population growth, economic activities, climate change, management of sewage and wastewater treatment systems. The DSS is also applied to a challenging scenario: the building of an in series reservoir for supplying the Capital (Salvador) of drinking water. The experience has been characterized also by a large involvement of local specialists, with the aim to emphasize the existing qualifications and to consider local culture

Brand influence in children's economic choices

La investigación tiene como objetivo verificar si la elección de los consumidores jóvenes depende de la marca de los productos. En particular, estudiamos las preferencias de los niños en lo que se refiere a cuatro tipos de productos (nombres de marca y no de marca): juguetes, artículos escolares, aperitivos y ropa. Nuestra hipótesis es que los niños optan por productos de marca y, en especial, que prefieren juegos y ropa, mientras muestran menos interés hacia los artículos escolares y refrigerios. Hemos llevado a cabo un estudio sobre una muestra de 106 niños de entre 6 y 11 años de edad; el cuestionario fue diseñado para entender las opciones y preferencias económicas de los niños. Se analizaron los datos a través del método de Thurstone de comparación por parejas (Pedon, 2005), que permitió la creación de una escala de intervalo en un continuo que representa el grado de preferencia de los estímulos dados. Los resultados confirman que los jóvenes consumidores prefieren productos de marca y, en especial, eligieron juegos. La investigación demuestra la utilidad del método que nos ha permitido describir con precisión el nivel de preferencia hacia los diferentes estímulos. Aunque muchos estudios ya habían demostrado que los jóvenes consumidores prefieren productos de marca, los resultados de éste mostraron que algunos productos, como los juegos y ropa, se eligen entre otros sin importar la marca.The research aims to verify if the choice of young consumers depends on the brand of products. In particular, we studied the children’s preferences referred to four kinds of products (brand and non-brand names): toys, school items, snacks and clothing. Our hypothesis is that children choose brand-name products and, they especially prefer games and clothes while they show less interest in school items and snacks. We carried out a study on a sample of 106 children between 6 and 11 years of age; the questionnaire was designed to understand the children’s economic choices and prefer- ences. We analysed the data through Thurstone’s method of paired comparison (Pedon, 2005) that allowed the creation of an interval scale on a continuum which represents the degree of preference of the given stimuli. The results confirm that young consumers prefer brand-name products and, in particular, they chose games. The research demonstrates the usefulness of the method that has allowed us to describe accurately the level of preference of the various stimuli. Although many studies had already shown that young consumers prefer branded products, the results of this study showed that some products, like games and clothes, are chosen over other regardless of brand.peerReviewe

Recovery of different waste vegetable oils for biodiesel production: a pilot experience in Bahia State, Brazil

In Brazil, and mainly in the State of Bahia, crude vegetable oils are widely used in the preparation of food. Street stalls, restaurants and canteens make a great use of palm oil and soybean oil. There is also some use of castor oil, which is widely cultivated in the Sert\ue3o Region (within the State of Bahia), and widely applied in industry. This massive use in food preparation leads to a huge amount of waste oil of different types, which needs either to be properly disposed of, or recovered. At the Laboratorio Energia e Gas-LEN (Energy & Gas lab.) of the Universidade Federal da Bahia, a cycle of experiments were carried out to evaluate the recovery of waste oils for biodiesel production. The experiences were carried out on a laboratory scale and, in a semi-industrial pilot plant using waste oils of different qualities. In the transesterification process, applied waste vegetable oils were reacted with methanol with the support of a basic catalyst, such as NaOH or KOH. The conversion rate settled at between 81-85% (in weight). The most suitable molar ratio of waste oils to alcohol was 1:6, and the amount of catalyst required was 0.5% (of the weight of the incoming oil), in the case of NaOH, and 1%, in case of KOH. The quality of the biodiesel produced was tested to determine the final product quality. The parameters analyzed were the acid value, kinematic viscosity, monoglycerides, diglycerides, triglycerides, free glycerine, total glycerine, clearness; the conversion yield of the process was also evaluated