27 resultados para hammers
Resumo:
This study aimed to evaluate the dynamic factor applied to the results obtained by dynamic resistance formulas Janbu and Hiley, would lead to the results obtained by static strength analysis CAPWAPC ®. The evaluation was done by backcalculation dynamic loading tests (ECD), taking into consideration the type of soil in which the cutting base precast concrete were settled, and using the information on the effective energy transmitted to the stakes by hammers, obtained by CAPWAPC ®. The results are shown in tables and graphs, and showed that the use of these formulations and their dynamic factors can become an efficient and economical field, assisting the engineer in making decisions regarding the staking of the work
Resumo:
Table of Contents: Crystal River’s Manatee Rescue Squad, page 3 Focus on . . . Birds and Birding, pages 8-15 Assessing Damage in an Arizona Wilderness, page 16 Have Hammers, Will Travel page 18
Resumo:
Wild bearded capuchin monkeys, Cebus libidinosus, use stone tools to crack palm nuts to obtain the kernel. In five experiments, we gave 10 monkeys from one wild group of bearded capuchins a choice of two nuts differing in resistance and size and/or two manufactured stones of the same shape, volume and composition but different mass. Monkeys consistently selected the nut that was easier to crack and the heavier stone. When choosing between two stones differing in mass by a ratio of 1.3:1, monkeys frequently touched the stones or tapped them with their fingers or with a nut. They showed these behaviours more frequently before making their first selection of a stone than afterward. These results suggest that capuchins discriminate between nuts and between stones, selecting materials that allow them to crack nuts with fewer strikes, and generate exploratory behaviours to discriminate stones of varying mass. In the final experiment, humans effectively discriminated the mass of stones using the same tapping and handling behaviours as capuchins. Capuchins explore objects in ways that allow them to perceive invariant properties (e.g. mass) of objects, enabling selection of objects for specific uses. We predict that species that use tools will generate behaviours that reveal invariant properties of objects such as mass; species that do not use tools are less likely to explore objects in this way. The precision with which individuals can judge invariant properties may differ considerably, and this also should predict prevalence of tool use across species. (C) 2010 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Resumo:
Chimpanzees have been the traditional referential models for investigating human evolution and stone tool use by hominins. We enlarge this comparative scenario by describing normative use of hammer stones and anvils in two wild groups of bearded capuchin monkeys (Cebus libidinosus) over one year. We found that most of the individuals habitually use stones and anvils to crack nuts and other encased food items. Further, we found that in adults (1) males use stone tools more frequently than females, (2) males crack high resistance nuts more frequently than females, (3) efficiency at opening a food by percussive tool use varies according to the resistance of the encased food, (4) heavier individuals are more efficient at cracking high resistant nuts than smaller individuals, and (5) to crack open encased foods, both sexes select hammer stones on the basis of material and weight. These findings confirm and extend previous experimental evidence concerning tool selectivity in wild capuchin monkeys (Visalberghi et al., 2009b; Fragaszy et al., 2010b). Male capuchins use tools more frequently than females and body mass is the best predictor of efficiency, but the sexes do not differ in terms of efficiency. We argue that the contrasting pattern of sex differences in capuchins compared with chimpanzees, in which females use tools more frequently and more skillfully than males, may have arisen from the degree of sexual dimorphism in body size of the two species, which is larger in capuchins than in chimpanzees. Our findings show the importance of taking sex and body mass into account as separate variables to assess their role in tool use. (C) 2011 Elsevier Ltd. All rights reserved.
Resumo:
The use of stones to crack open encapsulated fruit is widespread among wild bearded capuchin monkeys (Cebus libidinosus) inhabiting savanna-like environments. Some populations in Serra da Capivara National Park (Piaui, Brazil), though, exhibit a seemingly broader toolkit, using wooden sticks as probes, and employing stone tools for a variety of purposes. Over the course of 701.5 hr of visual contact of two wild capuchin groups we recorded 677 tool use episodes. Five hundred and seventeen of these involved the use of stones, and 160 involved the use of sticks (or other plant parts) as probes to access water, arthropods, or the contents of insects` nests. Stones were mostly used as ""hammers""-not only to open fruit or seeds, or smash other food items, but also to break dead wood, conglomerate rock, or cement in search of arthropods, to dislodge bigger stones, and to pulverize embedded quartz pebbles (licking, sniffing, or rubbing the body with the powder produced). Stones also were used in a ""hammer-like"" fashion to loosen the soil for digging out roots and arthropods, and sometimes as ""hoes"" to pull the loosened soil. In a few cases, we observed the re-utilization of stone tools for different purposes (N = 3), or the combined use of two tools-stones and sticks (N = 4) or two stones (N = 5), as sequential or associative tools. On three occasions, the monkeys used smaller stones to loosen bigger quartz pebbles embedded in conglomerate rock, which were subsequently used as tools. These could be considered the first reports of secondary tool use by wild capuchin monkeys. Am. J. Primatol. 71:242-251, 2009. (c) 2008 Wiley-Liss, Inc.
Resumo:
Appreciation of objects` affordances and planning is a hallmark of human technology. Archeological evidence suggests that Pliocene hominins selected raw material for tool making [1, 2]. Stone pounding has been considered a precursor to tool making [3, 4], and tool use by living primates provides insight into the origins of material selection by human ancestors. No study has experimentally investigated selectivity of stone tools in wild animals, although chimpanzees appear to select stones according to properties of different nut species [5, 6]. We recently discovered that wild capuchins with terrestrial habits [7] use hammers to crack open nuts on anvils [8-10]. As for chimpanzees, examination of anvil sites suggests stone selectivity [11], but indirect evidence cannot prove it. Here, we demonstrate that capuchins, which last shared a common ancestor with humans 35 million years ago, faced with stones differing in functional features (friability and weight) choose, transport, and use the effective stone to crack nuts. Moreover, when weight cannot be judged by visual attributes, capuchins act to gain information to guide their selection. Thus, planning actions and intentional selection of tools is within the ken of monkeys and similar to the tool activities of hominins and apes.
Resumo:
To determine whether tool use varied in relation to food availability in bearded capuchin monkeys, we recorded anvil and stone hammer use in two sympatric wild groups, one of which was provisioned daily, and assessed climatic variables and availability of fruits, invertebrates and palm nuts. Capuchins used tools to crack open encased fruits, mostly palm nuts, throughout the year. Significant differences between wet and dry seasons were found in rainfall, abundance of invertebrates and palm nuts, but not in fruit abundance. Catule nuts were more abundant in the dry season. We tested the predictions of the necessity hypothesis (according to which tool use is maintained by sustenance needs during resource scarcity) and of the opportunity hypothesis (according to which tool use is maintained by repeated exposure to appropriate ecological conditions, such as preferred food resources necessitating the use of tools). Our findings support only the opportunity hypothesis. The rate of tool use was not affected by provisioning, and the monthly rate of tool use was not correlated with the availability of fruits and invertebrates. Conversely, all capuchins cracked food items other than palm nuts (e.g. cashew nuts) when available, and adult males cracked nuts more in the dry season when catule nuts (the most common and exploited nut) are especially abundant. Hence, in our field site capuchins use tools opportunistically. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
Resumo:
Bereits im Jahre 1956 wurde bei Baugrund-Aufschlußbohrungen für das zweite Kurmittelhaus in Bad Bramstedt bei einer Serie von 11 Bohrungen - ausgeführt durch die Firma Fritz Eising K. G. in Hamburg - in drei benachbart gelegenen Bohrpunkten an der südlichen Ecke des Gebäudes in einer Teufe von ca. 10 m u. T. eine offensichtlich organogene Schicht von ca. 2 m Mächtigkeit erbohrt. Eines dieser Bohrprofile hat folgenden Aufbau: -5,8 m Fein-Mittelsand, -7,7 m Mittelsand, Fein-Mittelkies, -10,0 m Mittelsand, wenig Kies, -12,0 m Gyttja, -15,0 m Mittelsand, Grobsand. Die bereits wiedergegebene Teufenangabe ist insofern recht interessant, als im Jahre 1966 bei der Brücke über die Bramau bei Hitzhusen, demnach in der Talaue der Bramau in einer Teufe von 8,55 m ebenfalls eine Gyttja erbohrt wurde. Die Tiefenlagen beider Vorkommen scheinen sich demnach relativ zu entsprechen. Das gesamte Profil bei Hitzhusen ist in einigen Punkten abweichend ausgebildet und enthält vor allem noch ein zweites Gyttja-Band in 11,25 m Teufe. Im Einzelnen wurde hier durch die Bohrfirma Paul Hammers A. G., Hamburg, diese Schichtfolge angetroffen: -1.55 m Fein-Mittelsand, Humus, -3,10 m Mittel-Grobsand, Kies, Steine, etwas Lehm, -4,50 m Mittel-Grobsand, -7,20 m Mittel-Grobsand, Kies, -8,00 m Grobsand, -8,55 m Grobsand, Kies, -8,65 m Schluff-Gyttja, -9,70 m Fein-Grobsand, -10,25 m Mittel-Grobsand, Kies, -10,75 m Mittel-Grobsand, -11,25 m Mittel-Grobsand, Schluffstreifen, -11,40 m Schluff-Gyttja, -12,10 m Mittelsand, -12,30 m Mittel-Grobsand, Kies, -17,85 m Geschiebemergel. Die gewonnenen Proben der Schluff-Gyttjen wurden näher untersucht. Da es sich in beiden Fällen um geringmächtige Lagen handelt (0,1 m resp. 0,15 m), und das Material durchaus als stark feinsandig bis schluffig zu bezeichnen ist (das spricht für eine wesentlich schnellere Sedimentation, als die einer reinen biogenen Gyttja), ist der Effekt einer 'Mischprobe' weitgehend ausgeschlossen. Außerdem lagen die Proben - obgleich wahrscheinlich mit einem Ventilbohrer gefördert - als relativ ungestörte Brocken mit erhaltengebliebener Feinschichtung vor. Auf den Schichtflächen waren gröbere Pflanzenreste erkennbar (in der Tabelle angegeben). Der sehr hohe mineralische Anteil läßt zunächst den Verdacht auf sekundären Pollen aufkommen. Keines der beiden pollenanalytisch ermittelten Vegetationsbilder liefert dagegen irgendeine Bestätigung hierfür.
Resumo:
Bibliography: p. 22.
Resumo:
Making sense of auction sales, in terms of English contract law, is no easy task. Despite the common perception of hammers hitting blocks, signifying the creation of the basic sale contract,1 a typical auction sale necessarily involves the making of several forms of contract other than the obvious primary sale agreement. The purpose of this article, therefore, is threefold, namely, to (1) examine these various forms of contractual relationship2 which may come into existence as a result of a traditional (face to face) auction sale; (2) consider specifically the selling of land at public auction with a view to advocating a change in the law requiring the formality of writing for sales contracts of land for both private and public auctions, and (3) compare briefly the contractual elements of an online ascending model of auction sale typified by the eBay phenomenon.
Resumo:
Inscriptions: Verso: [stamped] Photograph by Freda Leinwand. [463 West Street, Studio 229G, New York, NY 10014].
Resumo:
The failure of materials is always an unwelcome event for several reasons: human lives are put in danger, economic losses, and interference in the availability of products and services. Although the causes of failures and behaviour of materials can be known, the prevention of such a condition is difficult to be guaranteed. Among the failures, wear abrasion by the low voltage is the kind of failure that occurs in more equipment and parts industry. The Plants Sucroalcooleiras suffer significant losses because of such attrition, this fact that motivated their choice for the development of this work. For both, were considered failures in the swing hammers desfibradores stopped soon after the exchange provided in accordance with tonnage of cane processed, then were analyzed by the level of wear testing of rubber wheel defined by the standard ASTM G65-91.The failures were classified as to the origin of the cause and mechanism, moreover, were prepared with samples of welding procedures according to ASME code, sec. IX as well, using the technique of thermal spraying to analyze the performance of these materials produced in laboratories, and compares them with the solder used in the plant. It was observed that the bodies-of-proof prepared by the procedure described as welding, and the thermal spraying the results of losing weight have been minimized significantly compared to the preparations in the plant. This is because the use of techniques more appropriate and more controlled conditions of the parameters of welding. As for the thermal spraying, this technique has presented a satisfactory result, but requires the use of these coatings in the best condition for real affirmation of the results