https://docentes.fct.unl.pt/lblm/files/refmodchem-2018---1.pdf

Piezoelectric energy harvesting has received great attention over the last 20 years. The main goal of this work is to discuss the potential advantages of introducing non-linearities in the dynamics of a beam type piezoelectric vibration energy harvester. The described device is essentially a cantilever beam partially covered by piezoelectric material with a force electromagnetically applied to the beam. Through experimental tests it has been confirmed the benefits of introducing non-linearities in these types of systems.

This paper investigates whether the model uncertainty of reinforced recycled aggregate concrete (RAC) beams subjected to bending differs from that of reinforced natural aggregate concrete (NAC) beams. An introductory remark concerning the importance of the codification of RAC structural design is made and notions concerning model uncertainties and their role on structural codification are given. Afterwards, the criteria used in the construction of a database of RAC and NAC beams are referred before presenting the key findings of an analysis on the model uncertainty of the cracking, yielding and ultimate moments of beams subjected to four-point bending tests. The analytical moments were calculated following Eurocode 2 provisions. Probabilistic models for model uncertainties are proposed. Negligible differences in the model uncertainty of NAC and RAC beams are reported.

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Molybdenum is essential to most organisms, being found in the active site of enzymes that catalyze redox reactions involving carbon, nitrogen and sulfur atoms of key metabolites. Some of the molybdenum-dependent reactions constitute key steps in the global biogeochemical cycles of carbon, nitrogen and sulfur, with particular emphasis on the atmospheric dinitrogen fixation into ammonium. Presently, more than 50 molybdoenzymes are known. The great majority are prokaryotic, with eukaryotes holding only a restricted number of molybdoenzymes. Tungsten, probably because of its limited bioavailability, is less used, being found most often in anaerobic thermophilic prokaryotes.

This chapter provides an overview on the molybdo- and tungstoenzymes.
Their physiological context and significance will be described in Section 1.2,where the recent hypothesis that the lack of molybdenum could have been the limiting factor for the life evolution and expansion on early Earth will receive special attention (Section 1.2.1). A brief introduction to the chemical properties that shape the catalytically competent molybdenum/tungsten centres will be made in Section 1.3. In Section 1.4, the enzymes will be grouped in five main families (Sections 1.4.1 to 1.4.5), according to their metal/cofactor structure, and a general view on the structural (section (a)) and mechanistic (section (b)) versatility of each family will be presented. A brief account of novel heteronuclear centres containing molybdenum, whose physiological function is not yet fully understood, will be made in Section 1.4.6. A final outlook on our present knowledge about these enzymes will conclude this chapter.

http://docentes.fct.unl.pt/lblm/files/mo_w_enzymes-rsc_book-chap_1.pdf

http://docentes.fct.unl.pt/lblm/files/ica-2017-455-350.pdf

Reduced-bias versions of a very simple generalization of the ‘classical’ Hill estimator of a positive extreme value index (EVI) are put forward. The Hill estimator can be regarded as the logarithm of the mean-of-order-0 of a certain set of statistics. Instead of such a geometric mean, it is sensible to consider the mean-of-order-p (MOP) of those statistics, with p real. Under a third-order framework, the asymptotic behaviour of the MOP, optimal MOP and associated reduced-bias classes of EVI-estimators is derived. Information on the dominant non-null asymptotic bias is also provided so that we can deal with an asymptotic comparison at optimal levels of some of those classes. Large-scale Monte-Carlo simulation experiments are undertaken to provide finite sample comparisons.Reduced-bias versions of a very simple generalization of the ‘classical’ Hill estimator of a positive extreme value index (EVI) are put forward. The Hill estimator can be regarded as the logarithm of the mean-of-order-0 of a certain set of statistics. Instead of such a geometric mean, it is sensible to consider the mean-of-order-p (MOP) of those statistics, with p real. Under a third-order framework, the asymptotic behaviour of the MOP, optimal MOP and associated reduced-bias classes of EVI-estimators is derived. Information on the dominant non-null asymptotic bias is also provided so that we can deal with an asymptotic comparison at optimal levels of some of those classes. Large-scale Monte-Carlo simulation experiments are undertaken to provide finite sample comparisons.