Significant hardness enhancement in an Al–Cu–Mg alloy with high Cu:Mg ratio by microalloying with Si and Ge

The evolution of hardness in an Al-Cu-Mg based alloy with high Cu:Mg ratio (= 2, at. %) microalloyed with Si and Ge was studied during artificial ageing treatment performed at 190 °C. The results were compared to those obtained in a similar alloy with no Mg content. The hardness evolution in the Mg containing alloy was similar to that of the Mg free alloy, but shifted by about 50 Hv to higher values for all ageing times. The peak hardness occurred after 3 h ageing in both alloys, with a value slightly above 200 Hv in the Mg containing alloy. The microstructure of the peak aged and the overaged condition were characterized by means of transmission electron microscopy (TEM). For the Mg-containing alloy the microstructure of the peak aged condition consisted of plate-shaped precipitates, with a very similar structure to that of the θ′ phase and a high density of small needle-shaped precipitates lying along the Al directions. In the peak aged and overaged conditions the needle-shaped precipitates were found to belong to the Q′ phase (Al4Cu2Mg8Si7) or its precursor phases, previously observed in the Al–Mg–Si system with minor Cu additions.Fil: Castro Riglos, Maria Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Morello, Nicolas. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Tolley, Alfredo Juan. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentin

Bioreactors landfills: comparison and kinetics of the different systems

The need for more sustainable landfilling has increased interest in bioreactor landfills as a suitable tool for optimising degradation processes. Bioreactors can be categorised as follows: anaerobic, aerobic, semi aerobic and hybrid. The choice of a specific bioreactor can be strongly influenced by the desired treatment objectives (i.e., energy recovery, increased rate of waste stabilisation, washing) as well as by the specific site conditions (e.g., waste characteristics, climate and social/economic situation, regulations). However, the increased rate of waste stabilisation should be the primary driving principle in the bioreactor landfill design (Cossu, 2010). Full-scale bioreactor landfills are still uncommon and one of the reasons is the perception that the effectiveness of this technology is not well demonstrated. This paper aims to contribute to filling this knowledge gap by analysing and comparing the lab scale applications of different types of bioreactors available in the literature and providing a survey of the different methods by considering their respective advantages and disadvantages. Qualitative analysis of the main types of bioreactor landfills is provided according to a few selected characteristics (i.e. energy recovery, biochemical kinetics, technological complexity, costs). Considering landfill sustainability, the discussion is primarily focused on the quantification of the stabilisation capability of the different bioreactors which is calculated in terms of COD and ammonia removal kinetics. The results demonstrate that the optimisation of COD removal kinetics is the highest in aerated bioreactors, while ammonia removal kinetics is maximum in hybrid bioreactors (i.e., 6 and 10 times higher, respectively, compared to the anaerobic bioreactors)

Il problema delle citazioni nella crisi del diritto comune. Interventi a carattere antigiurisprudenziale in alcuni ordinamenti italiani tra XV e XVIII secolo

Il presente lavoro si propone di esaminare come alcuni interventi diretti del potere assoluto, consistenti in provvedimenti autoritativi intesi a limitare le allegazioni in giudizio e le citazioni nelle sentenze, delle opiniones dei giuristi, e nell’obbligo di motivazione della sentenza, abbiano contribuito alla destabilizzazione del sistema normativo dello ius commune, avviandolo verso il suo inesorabile tramonto.This essay aims to examine how some actions of the absolute power, as authoritative measures that limited allegations and citations in judgments, contributed, together with jurists’ opiniones and with the obligation to state reasons, to destabilize the system of ius commune, initiating its sunset

Alle origini della tutela del lavoro minorile nello Stato unitario: la l. 11 febbraio 1886, n. 3657, a tutela dei bambini sfruttati

Il contributo intende analizzare il primo intervento dello Stato italiano, nella contrattazione privata e nella pratica dei rapporti tra datori di lavoro ed operai, posto in essere con la l. n. 3657 dell’11 febbraio 1886 a tutela del lavoro e dello sfruttamento minorile. Raggiunta da poco l'unificazione nazionale, la struttura economica del nostro Paese appariva, rispetto ad altre nazioni europee, ancora di tipo pre-industriale, e caratterizzata da pochi tentativi di passaggio dall'artigianato all'industria in determinati settori e solo nelle regioni del settentrione. Le condizioni dell'arretratezza dell'industria italiana, certamente poco sensibile alle esigenze di aggiornamento tecnico, hanno obbligato i datori di lavoro, costretti ad operare in un mercato fortemente concorrenziale e non garantito contro le merci straniere, verso le quali non era prevista alcuna forma di protezione, a sfruttare oltre ogni limite le condizioni più semplici, o per essere più precisi il basso costo del lavoro e l'assenza di protezione legale. Da qui un elevato quantitativo di forza lavoro infantile inserito (accanto a quella femminile: c.d. mezze forze) nel processo produttivo e utilizzato in lavori gravosi, nocivi e antigienici, con effetti praticamente deleteri dal punto di vista sanitario per le loro già tanto deboli condizioni fisiche, tra l'indifferenza dei datori di lavoro spinti prevalentemente dai loro interessi capitalistici a sfruttarli senza alcun vincolo legale, e la necessità sempre più impellente di tutelare questa manodopera.This essay intends to analyze the first intervention of the Italian State, in private bargaining and in the practice of relations between employers and workers, implemented with law 11 February 1886, no. 3657 for the protection of work and child exploitation. Soon after the national unification, the economic structure of Italy appeared, compared to other European nations, still of a pre-industrial type, and characterized by few attempts to move from craftsmanship to industry in certain sectors and only in the regions of north. The conditions of the backwardness of Italian industry, certainly not very sensitive to the need for technical updating, forced the employers, that mast operate in a highly competitive and unsecured market against foreign goods, to which no form was foreseen of protection, to exploit the simplest conditions beyond all limits, or to be more precise the low labor costs and the absence of legal protection. From here a great deal of child (together with the women: so-called half forces) in the production process and used in heavy, harmful and unhygienic works, with practically deleterious effects from the health point of view for their already so weak physical conditions, between the indifference of employers driven mainly by their capitalist interests to exploit them without any legal constraint, and the increasingly urgent need to protect this labor force

Alle origini della tutela degli infortuni sul lavoro

Il presente studio si propone di inquadrare dal punto di vista storico-giuridico le origini della tutela degli infortuni sul lavoro, mettendone in evidenza gli elementi definitori, ossia la causa violenta e l’occasione di lavoro.The present study aims to analyze from the historical-legal point of view the origins of the protection of work-related injuries. It brings to light the two peculiar facts of violent cause and occasion of work

Local reactions to tick bites

A retrospective histological and immunohistochemical study has been carried out in 25 cases of tick bites recorded in our Departments. The samples that included an attached tick showed a cement cone anchoring the mouthparts to the skin and a blood-soaked, spongiform appearance of the superficial dermis, with a mild neutrophilic and eosinophilic infiltration. The vessels displayed a loose multilayered endothelial proliferation, with plump endothelia, permeated with erythrocytes. A few of them were severed, allowing copious blood extravasation. The established lesions included the following: erythema chronicum migrans-like cases, foreign body granulomas-sometimes containing remnants of the mouthparts-cutaneous lymphoid hyperplasia, either of the T-cell or the B-cell type, and tick-bite alopecia. In both the T-cell and B-cell pseudolymphomas, several vessels showed concentric endothelial and perithelial proliferation similar to that seen in the acute lesions. In the tick-bite alopecia, a lymphocytic infiltrate attacked the permanent portion of the hair follicles, whose reaction was a noticeable hyperplasia of the fibrous sheaths, although only a minority of the hairs was destroyed. The observed alterations are specific in the acute lesions and in the alopecia, where they directly arise as a result of the interactions between the host's tissues and the antihemostatic, anti-inflammatory, and immunomodulatory chemicals contained in the tick saliva. In the other lesions, the changes seem less characteristic, although the fragments of mouthparts and the special vascular changes provide a clue to their etiolog