Multi-signal Accelerated Degradation Testing of Rolling Ball Bearings Through Radial Overload

Bearings are essential components in rotating machinery found in abundance in nuclear power plants. Bearing failure in nuclear power plants can lead to increased operations and maintenance costs and even plant trips. When developing maintenance procedures, it is ideal to minimize costs and equipment downtime while maximizing safety. Reactive, or run-to-failure, maintenance minimizes maintenance costs at the expense of operation costs and safety. Preventative, or time-based, maintenance maximizes safety and minimizes operation costs at the expense of equipment downtime and maintenance costs. Predictive, or condition-based, maintenance attempts to optimize overall costs while maintaining system safety and reducing downtown. Predictive maintenance uses online equipment condition assessment and remaining useful life (RUL) predictions to schedule inspection and maintenance actions. The development of methods for early and accurate RUL predictions for bearings has the potential to transform maintenance planning in the nuclear power industry, reducing operation and maintenance costs while maintaining or improving overall system safety, reliability, and economics. In order to develop robust RUL models, examples of run-to-failure data are needed. Using data collected during accelerated degradation tests has the advantages of being easily controlled and of providing ample data over relatively a short test period. A testbed has been designed and constructed that incites bearing failure through the application of a radial load. Several parameters are monitored continuously and online, including motor current, shaft rotational speed, acoustics and bearing vibration and temperature. Bearing maintenance in nuclear power plants to date has relied on vibration data analysis performed at defined inspection intervals. By including several process signals in the testbed design, recommendations are made for online monitoring of bearings in nuclear power plants that would augment, or perhaps replace, the current maintenance scheme with gains in safety, economics, and system reliability

Performance or Marketing Benefits? The Case of LEED Certification

Green building adoption is driven by both performance-based benefits and marketing based benefits. Performance based benefits are those that improve performance or lower operating costs of the building or of building users. Marketing benefits stem from the consumer response to green certification. This study illustrates the relative importance of the marketing based benefits that accrue to Leadership in Energy and Environmental Design (LEED) buildings due to green signaling mechanisms, specifically related to the certification itself are identified. Of course, all participants in the LEED certification scheme seek marketing benefits. But even among LEED participants, the interest in green signaling is pronounced. The green signaling mechanism that occurs at the certification thresholds shifts building patterns from just below to just above the threshold level, and motivates builders to cluster buildings just above each threshold. Results are consistent across subsamples, though nonprofit organizations appear to build greener buildings and engage in more green signaling than for-profit entities. Using nonparametric regression discontinuity, signaling across different building types is observed. Marketing benefits due to LEED certification drives organizations to build “greener” buildings by upgrading buildings at the thresholds to reach certification levels

Common dynamical features of sensory adaptation in photoreceptors and olfactory sensory neurons

Sensory systems adapt, i.e., they adjust their sensitivity to external stimuli according to the ambient level. In this paper we show that single cell electrophysiological responses of vertebrate olfactory receptors and of photoreceptors to different input protocols exhibit several common features related to adaptation, and that these features can be used to investigate the dynamical structure of the feedback regulation responsible for the adaptation. In particular, we point out that two different forms of adaptation can be observed, in response to steps and to pairs of pulses. These two forms of adaptation appear to be in a dynamical trade-off: the more adaptation to a step is close to perfect, the slower is the recovery in adaptation to pulse pairs and viceversa. Neither of the two forms is explained by the dynamical models currently used to describe adaptation, such as the integral feedback model

Risk Factors for Thyroid Cancer in Northern Italy

Franceschi S (Epidemiology Unit, Aviano Cancer Centre, Via Pedemontana Occ, 33081 Aviano (PN) Italy), Fassina A, Talamini R, Mazzolini A, Vianello S, Bidoli E, Serraino D and La Vecchia C. Risk factors for thyroid cancer in Northern Italy. International Journal of Epidemiology, 1989, 18: 578-584. We conducted a hospital based case-control study of 245 cases of thyroid cancer (62 males and 183 females) and 411 controls in three areas of Northern Italy, Subjects with thyroid cancer more often had a history of benign thyroid nodules (18 cases versus 0 controls, lower 95% confidence limit = 7.84), goitre (RR = 5.61, 95% confidence interval (CI): 2.13-14.77) and residence in endemic goitre areas (RR for residence longer than 20 years = 2.29, 95% CI: 1.23-4.29). Heavy (> 1000 rads) irradiation of the neck was reported only by seven cases (lower 95% confidence limit: 2.45). Among 31 food items considered, a few showed direct association, including starchy foods and various sources of animal fats or proteins, whereas frequent consumption of other foods, including major sources of dietary iodine (such as fish, green vegetables and fruit) gave significant protection. When analysis was restricted to various subgroups of patients (ie, different histological types, sexes and major groups of hospital controls), it yielded similar result

Risk Factors for Thyroid Cancer in Northern Italy

none8noneFranceschi S;Fassina A;Talamini R;Mazzolini A;Vianello S;Bidoli E;Serraino D;La Vecchia CFranceschi, S; Fassina, Ambrogio; Talamini, R; Mazzolini, A; Vianello, S; Bidoli, E; Serraino, D; La Vecchia, C

Silane-Mediated Expansion of Domains in Si-Doped κ-Ga2O3 Epitaxy and its Impact on the In-Plane Electronic Conduction

Unintentionally doped (001)-oriented orthorhombic κ-Ga2O3 epitaxial films on c-plane sapphire substrates are characterized by the presence of ≈ 10 nm wide columnar rotational domains that can severely inhibit in-plane electronic conduction. Comparing the in- and out-of-plane resistance on well-defined sample geometries, it is experimentally proved that the in-plane resistivity is at least ten times higher than the out-of-plane one. The introduction of silane during metal-organic vapor phase epitaxial growth not only allows for n-type Si extrinsic doping, but also results in the increase of more than one order of magnitude in the domain size (up to ≈ 300 nm) and mobility (highest µ ≈ 10 cm2V−1s−1, with corresponding lowest ρ ≈ 0.2 Ωcm). To qualitatively compare the mean domain dimension in κ-Ga2O3 epitaxial films, non-destructive experimental procedures are provided based on X-ray diffraction and Raman spectroscopy. The results of this study pave the way to significantly improved in-plane conduction in κ-Ga2O3 and its possible breakthrough in new generation electronics. The set of cross-linked experimental techniques and corresponding interpretation here proposed can apply to a wide range of material systems that suffer/benefit from domain-related functional properties

Influence of Polymorphism on the Electronic Structure of Ga2O3

The search for new wide band gap materials is intensifying to satisfy the need for more advanced and energy efficient power electronic devices. Ga$_2$O$_3$ has emerged as an alternative to SiC and GaN, sparking a renewed interest in its fundamental properties beyond the main $\beta$-phase. Here, three polymorphs of Ga$_2$O$_3$, $\alpha$, $\beta$ and $\varepsilon$, are investigated using X-ray diffraction, X-ray photoelectron and absorption spectroscopy, and ab initio theoretical approaches to gain insights into their structure - electronic structure relationships. Valence and conduction electronic structure as well as semi-core and core states are probed, providing a complete picture of the influence of local coordination environments on the electronic structure. State-of-the-art electronic structure theory, including all-electron density functional theory and many-body perturbation theory, provide detailed understanding of the spectroscopic results. The calculated spectra provide very accurate descriptions of all experimental spectra and additionally illuminate the origin of observed spectral features. This work provides a strong basis for the exploration of the Ga$_2$O$_3$ polymorphs as materials at the heart of future electronic device generations.Comment: Updated manuscript version after peer revie

Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition)

In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. For example, a key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process versus those that measure fl ux through the autophagy pathway (i.e., the complete process including the amount and rate of cargo sequestered and degraded). In particular, a block in macroautophagy that results in autophagosome accumulation must be differentiated from stimuli that increase autophagic activity, defi ned as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (inmost higher eukaryotes and some protists such as Dictyostelium ) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the fi eld understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. It is worth emphasizing here that lysosomal digestion is a stage of autophagy and evaluating its competence is a crucial part of the evaluation of autophagic flux, or complete autophagy. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. Along these lines, because of the potential for pleiotropic effects due to blocking autophagy through genetic manipulation it is imperative to delete or knock down more than one autophagy-related gene. In addition, some individual Atg proteins, or groups of proteins, are involved in other cellular pathways so not all Atg proteins can be used as a specific marker for an autophagic process. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field

Il ruolo della pianificazione nella citt\ue0 della nuova espansione in Mozambico: le sfide di una consolidata disciplina urbanistica

Il Mozambico, uno dei Paesi che ad oggi registra uno dei pi\uf9 rapidi tassi di urbanizzazione, si trova al centro di un grande processo di trasformazione e sviluppo socio-economico che sta velocemente cambiandone la conformazione territoriale. Oltre a questo, sta cambiando la maniera di espandersi delle sue citt\ue0 con una nuova domanda di abitazioni per la classe media urbana in crescita. Il Paesenegli anni \u201980deve la fondazione della Facolt\ue0 di Architettura e Pianificazione (UEM) alla Cooperazione Italiana ed al progetto interdisciplinare con la Facolt\ue0 La Sapienza. Ha da poco inaugurato, sempre tramite docenza italiana, la seconda Facolt\ue0 di Architettura e Pianificazione (UNILURIO) a Nampula, zona di grandi trasformazioni territoriali derivantidall\u2019apertura di nuove rotte commerciali. In Mozambico le questioni della citt\ue0 sono drammaticamente legate ai problemi ambientali. Impostando un ordinamento che rispondesse alle esigenze del contesto, l\u2019urbanistica \ue8 sempre stata promossa come uno strumento per studiare ipotesi caratterizzatedall'effettiva priorit\ue0 sociale degli interventi. I progetti dovevano essere credibili (possibili a breve termine ed in situazioni difficili)ed al tempo stesso culturalmente legati al dibattito ed alla ricerca comuni. L\u2019approccio base della disciplina \ue8 stato il considerare la citt\ue0 \u201cinformale\u201d come rappresentazione della citt\ue0 africana, avvicinandosi ad essacon umilt\ue0 ma intervenendovicon incisivit\ue0, cogliendonegli elementi della micro-strutturazione e cercando di rendere sopportabile un quadro di vita limite con risorse scarsissime. Oggi le sfidedell\u2019urbanistica in Mozambico non si limitano al dubbio di come fare un\u2019urbanistica o un\u2019architettura corretta per una realt\ue0 squilibrata, o a come includere nella pianificazione le dinamiche della citt\ue0 informale. Il paper si propone, partendo da una breve rilettura dell\u2019insegnamento dell\u2019urbanistica nel Paese, di analizzare quali siano le prossime sfide per la pianificazione urbana nel Paese e come si traducano in campo disciplinare. Inoltre prende in considerazione i nuovi possibili percorsi di ricerca interdisciplinari Italia-Mozambico, anche tramite il Master Post-Laurea, appena finanziato, sulla gestione delle aree informali (chiaro risultato dell\u2019importante impronta disciplinare passata). E\u2019 un momento di delicata transizione per il Mozambico, che si inserisce nel pi\uf9 ampio dibattito su cosa sia, oggi, la citt\ue0 dei Paesi in Via di Sviluppo. E\u2019 necessaria la definizione di un nuovo paradigma, e le Universit\ue0 in primis sono chiamate a questo compito, se si tiene in considerazione che la maggior parte dei laureati va a ricoprire, da sempre, importanti ruoli nella gestione della citt\ue0. Come mantenere l\u2019impronta sociale data all\u2019insegnamento dell\u2019urbanistica in un contesto in cui sono pi\uf9 che altro certe scelte politiche a definire il \u201cdisegno della citt\ue0\u201d \ue8 una delle sfide pi\uf9 ardue ed uno dei fattori determinanti nel futuro urbano di un Paese in rapida trasformazione