1,520 research outputs found
On the equilibrium problem and infinitesimal mechanisms of class theta tensegrity systems
No full textThis work presents a study on the equilibrium problem and the infinitesimal mechanisms of class θ= 1 tensegrity prisms. Local solutions of the self-equilibrium problem are numerically obtained through Newton-Raphson iterations. The presented results suggest that the analyzed structures can be usefully employed as building blocks of novel tensegrity metamaterials, due to their rich kinematic response and the considerably large number of infinitesimal mechanisms. © 2019 Author(s)
Nesomyrmex tshiguvhoae Mbanyana & Robertson, 2008, sp. nov.
No full textNesomyrmex tshiguvhoae sp. nov. Fig. 4a -c Description of worker Holotype. HL 0.885, HW 0.677, HW1 0.777, CI 76, SL 0.696, SI 103, PW 0.482, ML 1.052, EL 0.290, EI 43. Mandibles predominantly smooth, with longitudinal striations in parts. Median clypeus smooth and bordered by two pairs of longitudinal striations beyond which are further shorter striations. Anterior clypeal margin convex in dorsal view with a projecting translucent lamella medially. Eyes large with 16 ommatidia in the longest row. Scapes relatively long (SI 103). Head in full with face-view hind margin evenly convex. Promesonotum in profile evenly convex. Metanotal groove deeply impressed with a few strongly developed cross ribs. Metapleural gland bulla massively developed, particularly noticeable in dorsal view. Propodeal dorsum long and shallowly convex and sloping down to a short declivity that is demarcated from the dorsum by a pair of angled projections, too short to be termed teeth. Metapleural lobes low and rounded. Anterior peduncle with a small, shallow keel-like subpetiolar process. Anterior and dorsal faces of the node form a well-defined angle, from which the short dorsal face slopes evenly into the posterior face. Postpetiole similar in height to petiolar node and more bulky and rounded. Headinfull face view smooth and shiny posteriorly and medially, with a few fine striations posterior tothe lobes. Promesonotal dorsum smooth and shining, with superficial reticulate sculpture towards the metanotal groove. Metanotal groove with cross-ribs. Propodeal dorsum and declivity with transverse rugulae becoming irregular anteriorly. Petiolar node and postpetiole with irregular, superficial reticulate sculpture. Base of first gastral tergite with short costulae and the rest of the tergite smooth and shining. Dorsum of head with 10 short suberect hairs and sparse pubescence present. The venter of head with five curved hairs. Six pairs of erect hairs on the promesonotum; three pairs of erect hairs on the propodeum; four suberect hairs on the petiolar node; and six suberect hairs on the postpetiole; sparse pubescence present. Gastral tergite and sternite with evenly distributed short suberect hairs, acute apically. Colour uniformly dark brown. Paratypes. HL 0.767-0.924, HW 0.570-0.705, HW1 0.637-0.801, CI 73-78, SL 0.561-0.718, SI 94-105, PW 0.420-0.526, ML 0.865-1.114, EL 0.219-0.311, EI 38-44. (9 of 30 measured). Same as holotype except the following differences: mandibles either with longitudinal striations or smooth and shining. The dorsum of head with up to 15 suberect hairs; the venter of head with 5-10 curved hairs. Base of first gastral tergite with or without short costulae. Diagnosis This is a distinctive dark brown species with metapleural gland bulla large and bulging so that in dorsal view the sides below the propodeum are convex along their medial length; whereas in other species metapleural gland bulla is not prominent, indorsal view the sides below the propodeum are more-or-less straight along their medial length. Biology Recorded from Nama-Karoo north of Prince Albert and Renosterveld on tillite in the Nieuwoudtville region. Most specimens were caught in pitfalls but they were also in yellow pan traps, Malaise traps and from sweeping of vegetation. Etymology Named after Thidinalei Ennie Tshiguvho, who collected the holotype. Material examined Holotype: South Africa: Western Cape: 26 km from Prince Albert on Leeu Gamka road, 32°59'S 22°00'E, 10-19 October 1996, T.E. Tshiguvho, SAM-HYM-C009355. Paratypes: South Africa: Western Cape: 26 km from Prince Albert on Leeu Gamka road, 32°59'S 22°00'E, 10-19 October 1996, T.E. Tshiguvho, SAM-HYM-C009360 & SAM-HYM-C009356; 15 km from Prince Albert on Leeu Gamka road, 32°05'S 22°02'E, 10-19 October 1996, T.E. Tshiguvho, SAM-HYM-C009362, SAM-HYM-C009361 & SAM-HYM-C009359; Northern Cape: Hotbergsfontein farm, Boophone Site (4.64 km 125° SE Nieuwoudtville), 31°23'18"S 19°9'36"E, 12-19 October 2000, H.G. Robertson, D. Larsen & R. Adams, NW00-DN3-P07, SAM-HYM-C 019120; Hotbergsfontein farm, Boophone Site (4.64 km 125° SE Nieuwoudtville), 31°23.296'S 19°09.608'E, 12-19 October, S. van Noort & H.G. Robertson, NW00-DN3-Y217, SAM-HYM-C019121. Other material South Africa: Western Cape: 42 km from Prince Albert on Leeu Gamka road, 32°58S 21°58E, 10-19 October 1996, T.E. Tshiguvho, Site 30 Trap 5, SAM-HYM-C009358; Bleakhouse farm, Site B3, Nama-Karoo on dolerite soils, Pitfall, 32°15.41'S 22°54.93'E, 21-28 April 2001, H.G. Robertson & R. Tourle, BW01-B3-P10, SAM-HYM-C 019108; Kamferskraal farm, Site K4, Nama-Karoo on dolerite soils, Pitfall, 32°16.92'S 23°01.13'E, 22-29 April 2001, H.G. Robertson & R. Tourle, BW01-K4-P07; SAM-HYM-C019109; Kamferskraal farm, Site K4, Nama-Karoo on dolerite soils, Pitfall, 32°16.92'S 23°01.13'E, 22-29 April 2001, H.G. Robertson & R. Tourle, BW01-K4-P10; SAM-HYM-C019110; Kamferskraal farm, Site K5, Nama-Karoo on dolerite soils, Malaise trap, 32°17.45'S 23°58.46'E, 23 April 2001, S. van Noort & H.G. Robertson, BW01-K5- M16; SAM-HYM-C019111; Avondale farm, Site A3, Nama-Karoo on dolerite soils, Sweep, 32°13.33'S 22°57.53'E, Nama-Karoo on dolerite soils, Sweep, 19 April 2001, S. van Noort, BW01-A3-S104, SAM-HYM-C019112; Elandsfontein farm, Site E4, 32°17'41"S 23°0'0"E, 18 April 2001, H.G. Robertson, HGR00191, SAM-HYM-C017657; Helderberg Nature Reserve, Somerset West, 34°2'26"S 18°52'40"E, 01 March 2006, B. Braschler, Iimbovane 010306 1.9, SAM-HYM-C 019791; Beaufort West Karoo N.P., 32°20'23"S 22°31'19"E, flat Nama-Karoo, 12 March 2006, B. Braschler, Iimbovane Kar120306 F1.1, SAM-HYM-C019796; Beaufort West Municipal Land, near Central High School, 32°21'20"S 22°35'43"E, flat heavily disturbed Nama-Karoo, 13 March 2006, B. Braschler, Iimbovane SEN130306 2.3, SAM-HYM-C 019797; Northern Cape: Kortkop farm near Strydenburg, 30°09'S 23°44'E, Karoo vegetation, ex pitfall trap, 17 June 1995, B. Chambers, SAM-HYM-C008784; Merriman Station between Richmond and Britstown, 31°11'S 23°34'E, collected in the Karoo, March 2007, F. Duncan, PP1#2, SAM-HYM-C019581.Published as part of Mbanyana, N. & Robertson, H. G., 2008, Review of the ant genus Nesomyrmex (Hymenoptera: Formicidae: Myrmicinae) in southern Africa., pp. 35-55 in African Natural History 4 on page 3
Nesomyrmex vannoorti Mbanyana & Robertson, 2008, sp. nov.
No full textNesomyrmex vannoorti sp. nov. Fig. 3j -l Description of worker Holotype. HL 0.669, HW 0.521, HW1 0.561, CI 78, SL 0.441, SI 85, PW 0.382, ML 0.818, EL 0.197 EI 38. Mandibles with longitudinal striations. Clypeus with longitudinal striations, with central and posterior region of median portion smooth to faintly reticulate. Anterior clypeal margin evenly convex and with a projecting translucent lamella medially. Large eyes with 16 ommatidia in the longest row. Scapes of moderate length (SI 85). Head in full face-view hind margin shallowly convex. Promesonotum in profile evenly convex and metanotal groove conspicuously impressed.Propodeumunarmed;forminganevenconvexity with declivity. Anterior peduncle with a small tooth-like subpetiolar process. Petiolar node in profile evenly convex; posterior to the node is a moderately broad cylindrical portionof the petiole. Postpetiole inprofile low and rounded. Dorsumofhead with faint reticulate pattern and faint longitudinal striations between the eyes and behind the antennal insertions. Promesonotum finely reticulate, propodeal dorsum reticulate-punctate. Petiolar node and postpetiole finely reticulate pattern. First gastral tergite with a very short basal costulae and the rest of the tergite smooth and shining. Dorsum of head with short erect hairs mostly concentrated along two longitudinal lines. The venter of head with five straight hairs and two curved hairs. Promesonotal dorsum with at least four pairs of short, erect hairs, acute apically. Propodeum with two pairs of erect hairs, petiolar node with two pairs of suberect acute hairs apically and postpetiole with two pairs of suberect hairs. Regularly spaced suberect hairs on the gastral tergite and sternite. Head and gaster dark brown, with mesosoma and nodes light brown in colour. Paratypes. HL 0.620-0.698, HW 0.462-0.582, HW1 0.502-0.610, CI 75-81, SL 0.398-0.492, SI 80-93, PW 0.352-0.423, ML 0.751-0.944, EL 0.177-0.236, EI33-42 (22 of 45 measured). Same as holotype except the following differences: Mandibles either with longitudinal striations or smooth and shining. Dorsum of head smooth or with faint reticulate pattern between the eyes; fine longitudinal striations between the eyes and behind the antennal insertions present. Promesonotum either finely reticulate, or smooth and shining, with a fine, barely evident, inlaid reticulate pattern. The venter of head with 3-5 long hairs. Promesonotal dorsum with 3-4 pairs of short suberect hairs. Base of first gastral tergite either with or without costulae. Colour either uniformly medium brown or head and gaster dark brown, with mesosoma and nodes light brown. Diagnosis Nesomyrmex vannoorti is similar-looking to N. ruani, N. nanniae and N. entabeni. In all of them the unarmed propodeum formsaneven convexityandcolourismedium to dark brown. It is distinguished from the three latter species by having hairs on the propodeum. Biology Specimens were collected from pitfall traps, yellow pan traps and from sweeping in Nama-Karoo on dolerite soils and from Ruschia spinisa/Eriocephalis veld. Etymology Named after our colleague Dr Simon van Noort who is a Curator of Entomology at Iziko South African Museum and who collected the holotype. Material examined Holotype: South Africa: Western Cape: Avondale farm, 32°15.00'S 22°56.60'E, 19 April 2001, S. van Noort, BW01-A1-S82, SAM-HYM-C019103 Paratypes: South Africa: Western Cape: Avondale farm, 32°15.00'S 22°56.60'E, 22-29 April 2001, H.G. Robertson & R Tourle, BW01-A1-P09, SAM-HYM-C019093; Avondale farm, 32°15.00'S 22°56.60'E, 22-29 April 2001, S. van Noort & D.Larsen, BW01-A1-Y95, SAM-HYM-C019095; Avondale farm, 32°13.33'S 22°57.53'E, 22-29 April 2001, H.G. Robertson & R. Tourle, BW01-A3-P08, SAM-HYM-C 019096; Avondale farm, 32°14.31'S 22°58.59'E, 22-29 April 2001, H.G. Robertson & R. Tourle, BW01-A4-P07, SAM-HYM-C019098; Avondale farm, 32°14.31'S 22°58.59'E, 22-29 April 2001, H.G. Robertson & R. Tourle, BW01-A4-P09, SAM-HYM-C019098; Avondale farm, 32°15.00'S 22°56.60'E, 22-29 April 2001, H.G. Robertson & R. Tourle, BW01-A1-P09, SAM-HYM-C019093; Avondale farm, 32°14.31'S 22°58.59'E, 22-29 April 2001, S. van Noort & D. Larsen, BW01-A4-Y107, SAM-HYM-C019106; Avondale farm 32°14.31'S 22°58.59'E, 22-29 April 2001, H.G. Robertson & R. Tourle, BW01-A4-P02, SAM-HYM-C 019097; Avondale farm, 32°14.31'S 22°58.59'E, 22-29 April 2001, S. van Noort & D. Larsen, BW01-A4-Y103, SAM-HYM-C 019107; Tierberg near Prince Albert, 33°10'0"S 22°16'0"E, 12 September 1995, H. Adie, Ref. no. 094, SAM-HYM-C008454; Tierberg near Prince Albert, 33°10'0"S 22°16'0"E, 11 September 1995, H. Adie, SAM-HYM-C008785. Other material South Africa: Western Cape: Elandsfontein farm, Site E1, 32°17.69'S 22°55.53'E, Nama-Karoo on dolerite soils, Sweep, 21 April 2001, S. van Noort, BW01-E1S155, SAM-HYM-CO19102; Kamferskraal farm, Site K3, 32°13.83'S 22°58.59'E, Nama-Karoo on dolerite soils, Pitfall, 22-29 April 2001, H.G. Robertson & R. Tourle, BW01-K3-P06, SAM-HYM-C019101; Bleakhouse farm, Site B3, 32°15.41'S 22°54.93'E, Nama-Karoo on dolerite, Yellow pan trap, 21-28 April 2001, S. van Noort & D. Larsen, BW01-B3-Y73, SAM-HYM-C019105; 33 km from Seekoegat on Prince Albert road, 33°10'S 22°14'E, 10-19 October 1996, T.E. Tshiguvho, SAM-HYM-C009365; 10 km from Prince Albert on Leeu Gamka road, 33°07'S 22°02'E, 10-19 October 1996, T.E. Tshiguvho, SAM-HYM-9354; Northern Cape: Kortkop farm near Strydenburg, 30°09'S 23°44'E, Karoo vegetation, ex pitfall trap, 17 June 1995, B. Chambers, SAM-HYM-C008766; Merriman Station between Richmond and Britstown, 31°11'S 23°34'E, collected in the Karoo, March 2007, F. Duncan, PP1#2, SAM-HYM-C019585.Published as part of Mbanyana, N. & Robertson, H. G., 2008, Review of the ant genus Nesomyrmex (Hymenoptera: Formicidae: Myrmicinae) in southern Africa., pp. 35-55 in African Natural History 4 on page 3
Full 3D CAD procedure for the speedy evaluation of the seismic vulnerability of masonry towers
No full textA very straightforward 3D CAD approach for the speedy evaluation of the seismic vulnerability of existing masonry towers is presented. The procedure requires only the detailed 3D geometric model of the structure and automatically calculates the collapse acceleration on a user defined failure mechanism. In this paper, few pre-assigned mechanisms are tested, as for instance vertical splitting, simple overturning at the base, rocking with inclined yield lines and combined rocking and vertical splitting. The restriction of the possible tower failure within such a few mechanisms grounds on previous numerical research in the field and post-earthquake surveys experience. In any case, any user can define his own mechanisms according to the specificity of the case-study under consideration, directly shaping distinct volumes inside the CAD software. The procedure is automatized and the direct application of the principle of virtual works-assuming that masonry behaves as a no-tension material-allows the immediate evaluation of the horizontal acceleration at collapse. The mechanism associated to the minimum acceleration, in agreement with the kinematic theorem of limit analysis, is that most probably would occur in reality during a seismic event. The approach allows a straightforward evaluation of the seismic vulnerability of a tower and can be used even by practitioners not familiar with advanced FE computations and limit analysis concepts, so adapting well to the heterogeneous community involved in cultural heritage preservation. The automatized procedure is applied in this paper to a historical tower located in central Italy, to show the capabilities of the approach. © 2019 Author(s)
Members of the Vernon hockey team with their 1903/04 B.C. championship trophy
No full textB (L-R): A.O. Cochrane, Leonard Norris, T.E. Crowell, S.C. Smith, O.J. Vail. M (L-R): A. McQueen, R.H. Robertson, E. Elworthy, W. Sawyer, O. St. Clair Mabee. F (L-R): , E.S. Jackson, E. Smith
The Arab peoples of T.E. Lawrence's Seven Pillars of Wisdom in the light of post-colonial theory
No full textIt can be said that The Seven Pillars of Wisdom is a work whose true potential has not yet been discovered. That the work presents itself to be of greater value than may have previously seemed goes without question. However, during the more than eighty years of its existence, it was the author and not the work that created major interest in the academic world. The complicated character of T.E. Lawrence offered itself to psycho-analyst interpretation and most critiques have been built on these premises. Other works have concentrated on major historical events in Lawrence's life creating thorough biographies and numbers of fascinating approaches, some more, some less misleading were created. However. The Seven Pillars of Wisdom (from henceforth "Seven Pillars") foremostly survived in the shadows of David Lean's film "Lawrence of Arabia" and it was only during the late seventies, that concentration on the Seven Pillars as a text had begun to be cultivated. Additionally, it has only been during the past few years that works by writers such as Gertrude Bell, T.E. Lawrence or Charles M. Doughty have begun to gain a larger public interest. The aim of this work, however, is not to analyse the historical purpose of Lawrence's presence in the Middle East, nor to align the Seven Pillars with historical facts. Such..
The Arab peoples of T.E. Lawrence's Seven Pillars of Wisdom in the light of post-colonial theory
No full textIt can be said that The Seven Pillars of Wisdom is a work whose true potential has not yet been discovered. That the work presents itself to be of greater value than may have previously seemed goes without question. However, during the more than eighty years of its existence, it was the author and not the work that created major interest in the academic world. The complicated character of T.E. Lawrence offered itself to psycho-analyst interpretation and most critiques have been built on these premises. Other works have concentrated on major historical events in Lawrence's life creating thorough biographies and numbers of fascinating approaches, some more, some less misleading were created. However. The Seven Pillars of Wisdom (from henceforth "Seven Pillars") foremostly survived in the shadows of David Lean's film "Lawrence of Arabia" and it was only during the late seventies, that concentration on the Seven Pillars as a text had begun to be cultivated. Additionally, it has only been during the past few years that works by writers such as Gertrude Bell, T.E. Lawrence or Charles M. Doughty have begun to gain a larger public interest. The aim of this work, however, is not to analyse the historical purpose of Lawrence's presence in the Middle East, nor to align the Seven Pillars with historical facts. Such..
Minimum MSE estimation of a regression model with fixed effects from a series of cross sections (Revised version)
No full textEstimation
Pretoriana, no. 052, Dec. 1966
No full textMessage from the Mayor = Boodskap van die Burgemeester / J.F. Becker -- Gelukwensing van Dr. Willem Punt -- Dr. T.S. van Rooyen, 'n waardering / J.H. Hattingh -- Na vyftien jaar / G. v. W. Eybers -- An appreciation of Pretoriana, 1951-1966 / W.S. Robertson -- Vyftien jaar, meer as vyftig uitgawes van Pretoriana / Jan Ploeger -- Simpatiebetuiging i.s. wyle Mev. P.M. Beezhold -- Dr. Jan Ploeger en Pretoriana / F.J. du Toit Spies == Frederik Willem Beezhold Sr. en Jr. / H.M. Rex -- Joan Hoskyn Davies / J.H. Mienie -- My indebtedness to Pretoriana / T.E. Andrews -- Norman Eaton -- Johan Christiaan Vlok, in memoriam / J. Ploeger -- Norman Eaton was the finest architect in the country / A.L. Meiring -- Norman Eaton : biographical notes -- Presidents' biographies portrayed / Pretoria News -- Esteemed members of Old Pretoria Society ... quoted by Randolph Churchill / W.S. Robertson -- Mev. A.W. (Tissa) Eybers, in memoriam -- Mnr. A.M. Davey skrywe uit Kaapstad -- A monument to Johann Rissik in Arcadia Park / C.J. Beanes -- The arrival of the first Trans-African plane in Pretoria / H.P.H. Behrens -- Onthulling van twee gedenkplate op Krugerdag, 1966 / N.A. Coetzee -- Jaarverslag = Annual report 196
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