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

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

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

Solar panel simulator

This is a funny kind of power supply, not stable in voltage or in current: it simulates the comportment of a solar panel and can be very useful if you are playing around a solar powered device in a raining day. We designed it for internal use, but it may have a general value

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

Promoting individual and organizational ocbs: the mediating role of work engagement

In today's dynamic organizational environment, employees with a tendency to display discretional behaviors beyond their prescribed formal job duties represent a plus. Underpinned by the theories of social exchange and conservation of resources, these behaviors can be influenced by their level of job satisfaction (JS), defined as the extent to which employees like their work, and work engagement (WE), defined as a positive work-related state of mind. The present study investigates the mediating mechanism of WE in the relationship between JS and organizational citizenship behaviors (OCBs), which refer to discretionary behaviors that could benefit an organization (OCBs-O) and/or its members (OCBs-I). The mediational hypothesis is examined using structural equation modeling (SEM) among 719 Italian private and public sector employees. The significance of total, direct, and indirect effects was tested via bootstrapping. The results showed that JS was positively related to WE, which, in turn, was positively related to both OCBs-I and OCBs-O. The SEM results supported the hypotheses: WE fully mediated the relationship between JS and OCBs-I, and it partially mediated the relationship between JS and OCBs-O. This study sheds new light on this mechanism. Consequently, it is useful for HRM policy. It also helps us to better understand how satisfied and engaged employees are willing to adopt positive organizational behaviors

Dimensionality, reliability and validity of a multidimensional job insecurity questionnaire. preliminary findings in the italian context

Job insecurity is considered one of the major work stressors in the contemporary working life. Despite a long tradition of research, to date many questions about job insecurity are still open, including those regarding its measurement model. The present study aimed to introduce a Multidimensional Job Insecurity Questionnaire (MJIQ) and provide support for its psychometric properties. The MJIQ was composed by 20 items and is aimed at offering a complete and balanced assessment of job insecurity in its major dimensions (i.e. quantitative and qualitative) and narrow facets (affective and cognitive). Participants were employees from private and public Italian organizations (N=405). Results of Exploratory Factor Analysis supported the emergence of two major dimensions, namely quantitative and qualitative job insecurity. The invariance of the measurement model tested via Multi-group Confirmative Factor Analysis showed that the MJIQ parameters were invariant across gender. The two major dimensions of job insecurity evidenced good reliability and strong concurrent validity with wellknown job insecurity outcomes. Overall, these preliminary results show that MJIQ is a reliable and valid measure to tap the complexity of the job insecurity construct

Job crafting and job satisfaction in a sample of Italian teachers: the mediating role of Perceived Organizational Support

We aimed to explore the mediating role of perceived organizational support (POS) on the relationship between job crafting and job satisfaction, which is considered as an important outcome for the development of well being at work. Participants were 263 teachers from public schools in the South of Italy. Results indicated that POS fully mediated the relationship between job crafting and job satisfaction. Implications for management educational practice and limitations of the study are discussed

Radar Systems for Glaciology

This chapter deals with radar systems, measurements and instrumentation employed to study the internal core and bedrock of ice sheets in glaciology. The Earth's ice sheets are in Greenland and Antarctica. They cover about 10% of the land surface of the planet. The total accumulated ice comprises 90% of the global fresh water reserve. These ice sheets, associated with the ocean environment, provide a major heat sink which significantly modulates climate. Glaciology studies aim to understand the various process involved in the flow (dynamics), thermodynamics, and long-term behaviour of ice sheets. Studies of large ice masses are conducted in adverse environmental conditions (extreme cold, long periods of darkness). The development of remote sensing techniques have played an important role in obtaining useful results. The most widely used techniques are radar systems, employed since the 1950s in response to a need to provide a rapid and accurate method of measuring ice thickness. Year by year, polar research has become increasingly important because of global warming. Moreover, the discovery of numerous subglacial lake areas (water entrapped beneath the ice sheets) has attracted scientific interest in the possible existence of water circulation between lakes or beneath the ice (Kapitsa et al., 2006; Wingham et al., 2006; Bell et al., 2007). Recent studies in radar signal shape and amplitude could provide evidence of water circulation below the ice (Carter 2007, Oswald and Gogineni 2008). In this chapter the radar systems employed in glaciology, radio echo sounding (RES), are briefly described with some interesting results. RES are active remote sensing systems that utilize electromagnetic waves that penetrate the ice. They are used to obtain information about the electromagnetic properties of different interfaces (for example rock-ice, ice-water, seawater-ice) that reflect the incoming signal back to the radar. RES systems are characterized by a high energy (peak power from 10 W to 10 KW) variable transmitted pulse width (about from 0.5 ns to several microseconds) in order to investigate bedrock characteristics even in the thickest zones of the ice sheets (4755 m is the deepest ice thickness measured in Antarctica using a RES system). Changing the pulse length or the transmitted signal frequencies it is possible to investigate particular ice sheet details with different resolution. Long pulses allows transmission of higher power than short pulses, penetrating the thickest parts of the ice sheets but, as a consequence, resolution decreases. For example, the GPR system, commonly used in geophysics for rock, soil, ice, fresh water, pavement and structure characterization, employs a very short transmitted pulse (0.5 ns to 10 ns) that allow detailing of the shallow parts of an ice sheet (100-200 m in depth) (Reynolds 1997). Consequently, in recent years, GPR systems are also employed by explorers to find hidden crevasses on glaciers for safety. RES surveys have been widely employed in Antarctic ice sheet exploration and they are still an indispensable tool for mapping bedrock morphologies and properties of the last unexplored continent on Earth. The advantage of using these remote sensing techniques is that they allow large areas to be covered, in good detail and in short times using platforms like aeroplanes and surface vehicles