Influência do desgaste das garras dos pneus e das condições superficiais do solo nas operações de campo de um trator agrícola

The objective of this work was to compare the performance of a tractor equipped with used and new bias-ply tires (63.4% and 41.2%, front and rear tire waste, respectively), in three surface conditions: tillage soil, vegetal covered soil and firm soil. Field data were collected to calculate: forward speed, front and rear slippage tires, drawbar pull, available power at drawbar bar and fuel consumption. Results showed that both, tires and soil conditions, changed tractor capacity on developing drawbar traction. The worst performance was observed on tillage soil. The best performance of the tractor was observed at firm soil track. On the track with tilled soil, results showed that the forward speed was the lowest among the three soil conditions due to the front and rear slippage tires which was higher than vegetal covered and firm soil tracks. Fuel consumption results showed higher values on tilled tracks when compared with firm and vegetal covered tracks. The fuel consumption levels evaluated on bias-ply tires lead to significant changes on tractor’s performance at tilled soil, indicating that, at this condition, it’s necessary to replace the used tires by new tires. For vegetal covered soil operations, and also on firm soil conditions, used tires, at studied levels, indicated that these tires might still be used without tractor performance changing.

Hydrodynamic theory of liquid slippage on a solid substrate near a moving contact line

In this Letter a hydrodynamic theory of liquid slippage on a solid substrate near a moving contact line is proposed. A family of spatially varying slip lengths in the Navier slip law recovers the results of past formulations for slip in continuum theories and molecular dynamics simulations and is consistent with well-established experimental observations of complete wetting. This formulation gives a general approach for continuum hydrodynamic theories. New fluid flow behaviors are also predicted yet to be seen in experiment. © 2013 American Physical Society.

Slippage: Reclaiming personal family history through contemporary photomedia

This paper addresses the role of photography as a documentary medium and how this forms a basis for my practice-led studio investigations. In it, I will explore how photography is used to create histories and sustain specific notions of ‘legacy’ within the context of the family photo album. Family history is often based on stories to which the photo album provides a visual point of reference. Despite the ostensible ‘objectivity’ of the family photograph though it is nonetheless as subjective as the stories that surround it. In this way, the photo album perpetuates a hegemony of truth that obscures the fragmentary and highly selective nature of these documents and stories. The result is that every photo album implicitly documents the gaps or voids present in understandings of our own histories. Homi Bhabha refers to these kinds of voids as ‘disjunctive historical spaces’ – spaces of slippage that create the opportunity for new narratives and understandings to occur. Using Bhabha’s ideas as a chief point of reference, I will explore how these voids or gaps in information – and the opportunities for re-examination that they open up - can be explored through contemporary photomedia. Digital technologies such as camera phones and scanners generate a space in which photography’s own documentary conventions can be turned in on themselves to create a subterfuge. My current studio-based research involves using the scanner to navigate through my family’s sometimes-‘occulted’ history, in order to explore, document and recover my connection to this narrative. I am primarily interested in the scanner as a tool for capturing not simply surfaces, but objects, moments or movements in time. Objects or moments captured by the scanner can often be simultaneously distorted and consolidated, blurred and sharpened. This paper will propose that this ‘slippage’, literally expressed in the disruption of the pixelated field, can be used to create a space in which alternative readings or understandings of past events can be explored and new narratives produced.

Valorization of scrap tires pyrolysis oil (STPO) through a 2-stage hydrotreating-hydrocracking strategy. Process variables and kinetic modeling

232 p.

Assessment of estrogenic activity of leachate from automobile tires with two in vitro bioassays

In this study, a combination of enzyme-linked receptor assay (ELRA) and yeast estrogen screen (YES) assay was firstly applied to determine whether automobile tires immersed in fresh water can leach chemicals, which display estrogenic activity. We optimized ELRA substituting the chromogene substrate by a luminescent one, and found that luminescent ELBA was more sensitive to 17 beta-estradiol (17 beta-E2) with a detection limit of 0.016 mu g/l, compared to 0.088 mu g/l in the chromogene version. In ELRA, all tire leachates obviously showed estrogenic activity, which was increased with duration of immersion. Moreover, the leachate from hackled tires showed more potent estrogenicity than that from the whole ones. In comparison to ELRA, no detectable estrogenic activity was found in all tire leachates with YES assay. The results from YES assay further evidenced that antiestrogenic compounds can be leached from tires. As tire leachates contain estrogenic compounds, they could be important pollution sources, potentially harmful to wildlife and human health. Thus, use of shredded tires as road fill or in landfill sites should arouse our attention.

Vacuum pyrolysis of waste tires with basic additives

Granules of waste tires were pyrolyzed tinder vacuum (3.5-10 kPa) conditions, and the effects of temperature and basic additives (Na2CO3, NaOH) on the properties of pyrolysis were thoroughly investigated. It was obvious that with or without basic additives, pyrolysis oil yield increased gradually to a maximum and subsequently decreased with a temperature increase from 450 degrees C to 600 degrees C, irrespective of the addition of basic additives to the reactor. The addition of NaOH facilitated pyrolysis dramatically, as a maximal pyrolysis oil yield of about 48 wt% was achieved at 550 degrees C without the addition of basic additives, while a maximal pyrolysis oil yield of about 50 wt% was achieved at 480 degrees C by adding 3 wt% (w/w, powder/waste tire granules) of NaOH powder. The composition analysis of pyrolytic naphtha (i.b.p. (initial boiling point) similar to 205 degrees C) distilled from pyrolysis oil showed that more dl-limonene was obtained with basic additives and the maximal content of dl-limonene in pyrolysis oil was 12.39 wt% which is a valuable and widely-used fine chemical. However, no improvement in pyrolysis was observed with Na2CO3 addition. Pyrolysis gas was mainly composed of H-2, CO, CH4, CO2, C2H4 and C2H6. Pyrolytic char had a surface area comparable to commercial carbon black, but its proportion of ash (above 11.5 wt%) was much higher.

Liste ordinaire de 270 actions et 240 dixièmes d'action tirées à la loterie de la Compagnie des Indes le 25 janvier 1731...

[Acte. 1731]

« Sciences de la terre et du nom, ou Agla des Hébreux, avec plusieurs remarques et les Roues alphabétiques des nombres, des plus anciens autheurs, en partie tirées de l'hébraïque, dédiée[s] à monseigneur messire Jacques de Souvré, chevalier de Malte, grand-prieur de France, ambassadeur extraordinaire près la personne du Roy, en France », par monsieur « DE JOUVENCOURT. » (1er janvier 1670).

Traité de science occulte, en deux parties, la première (page 8), en 19 chapitres, appelée « Science de la terre », la seconde (page 234), en 20 chapitres, « Science du nom » ou traité de « Néomance » ou « Néomancie ». Figures dans la 2e partie. — Table des chapitres à la fin du volume. En tête du volume (page I), grand dessin lavé, représentant Jacques de Souvré, en buste, avec ses armoiries. A la page III, on lit : « Ex dono d[omini] Vallant. »

Recueil de copies de pièces, tirées des registres du parlement de Rouen, sur l'administration et la police de la ville de Rouen, etc.

On y remarque : « Ordonnances d'Admiralité, » 1517 (fol. 187) ; — « Oraison de monsr. le chancellier Olivier pour le Roy en la convention des estatz de Allemaigne » (fol. 257) ; — « Abbus de court d'église et des officiers de l'archevesque de Rouen » (fol. 278) ; — Deux mémoires sur les Ambassadeurs (fol. 318) ; — « Estat des deniers deubz sur les finances de ce royaume, tant à interestz que autrement du temps des feuz roys de bonne mémoire Françoys Ier et Henry IIe » (fol. 367). Provient peut-être d'Émery Bigot.

« Remarques tirées du livre de l'Harmonie universelle du P. MERSENNE, ainsy qu'il les avoit escrites, de sa main, à la marge et aux feuillets blancs devant et derrière dudit livre ».

Contient : Academia Parisiensis viros clarissimos Galilæi familiares et amicos lyncæos precatur, uti sequentibus in Dialogorum libros notis respondeant... et ad eximium geometram Genuensem D. Sanctininum mittant,... 1643 »