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  • Aircraft Propulsion and Power  (37)
  • 42.75  (26)
  • 1950-1954  (63)
  • 1
    Publication Date: 2014-07-15
    Description: Sound pressure levels, frequency spectrum, and jet velocity profiles are presented for an engine-afterburner combination at various values of afterburner fuel - air ratio. At the high fuel-air ratios, severe low-frequency resonance was encountered which represented more than half the total energy in the sound spectrum. At similar thrust conditions, lower sound pressure levels were obtained from a current fighter air craft with a different afterburner configuration. The lower sound pressure levels are attributed to resonance-free afterburner operation and thereby indicate the importance of acoustic considerations in afterburner design.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E54G07
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  • 2
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.33 (1954) nr.6 p.41
    Publication Date: 2013-03-01
    Description: Unter diesem Titel, indessen mit dem Zusatz „unter Benutzung des Materials der Kollektion Eisner, Dahlem" — die Sammlung befindet sich z.Zt. im Rijksmuseum van Natuurlijke Historie, Leiden — haben mein Freund Felix Bryk und ich die Gruppen Parnassius mnemosyne L., P. stubbendorfi Ménétr., P. eversmanni Ménétr., P. nordmanni Ménétr., P. clarius Eversm., P. clodius Ménétr., P. Orleans Ch. Oberth., P. apollonius Eversm., P. honrathi Staud. und A. Bang-Haas, P. bremeri Bremer, P. phoebus F., P. actius Eversm., P. jacquemontii Boisd., P. epaphus Ch. Oberth., P. tianschanicus Ch. Oberth., P. nomion Hb. und einen Teil von P. apollo L. kritisch bearbeitet, bis die Entwicklung der politischen Verhältnisse in Deutschland die weitere Herausgabe der „Parnassiana" durch uns unmöglich machte und dadurch unsere Arbeit unterbrach. Wäre der Weltkrieg nicht ausgebrochen, hätten wir wahrscheinlich einen Weg gefunden, um das uns an's Herz gewachsene Werk schon längst fortzusetzen. Bryk weilt nun in Stockholm, mein Wohnsitz ist Den Haag, die enge Zusammenarbeit der Vergangenheit ist nicht möglich. Ich habe mich deshalb gefragt, ob ich es ohne die Unterstützung von Bryk's tiefem Wissen um die Parnassier und ohne seine kritische Kontrolle wagen kann, allein mit der Revision der Gattung fortzufahren. Ich habe aber das Gefühl, damit doch einen Beitrag zu der Kenntnis dieser interessanten Lepidopteren-Familie leisten zu können, und habe mich angemutigt durch meine Leidener Freunde entschlossen, dies zu tun. Herr Professor Boschma, dem ich dafür zu grossem Dank verpflichtet bin, hat mir angeboten, für die Veröffentlichung meiner Arbeiten in einer Form sorgen zu wollen, die es gestatten wird, diese separat zu sammeln und als Fortsetzung der früheren Veröffentlichung in „Parnassiana" zu ge-
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 3
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1954) nr.24 p.291
    Publication Date: 2013-03-01
    Description: In the taxonomy of Coccoidea or scale insects much confusion is due to an insufficient knowledge of the type species of several genera. Especially our knowledge of some of the older genera is very incomplete, as the descriptions of their type species are extremely short and superficial from the modern point of view. The type specimens, on which the original descriptions of the genera were based, are distributed over several museums in all parts of the world; in some cases type material is no longer in existence, and as far as available it is seldom lent to persons in foreign countries. In consequence of this we have often to rely on the original description, as the type material is not available for examination. Signoret (Essai sur les Cochenilles, 1868-1876) was one of the first to describe the microscopical details of the genera and species which he introduced. He boiled his specimens in a solution of caustic potash to make microscopical preparations of the chitinous parts and did not hesitate to prepare even unique specimens ("que nous n'avons pas hésité à sacrifier dans l'intérêt de la science, tout en conservant les préparations bonnes à consulter, pensant qu'elles seraient ainsi plus utiles qu'une masse informe attachée à un épingle et qui ne peut présenter aucun caractère que l'on puisse énumérer"). In many cases, however, his descriptions are not detailed enough for the needs of present taxonomy. As the number of described species has increased greatly since Signoret's time, it has become necessary to pay attention to several minute details which were formerly of no importance to separate the species then known. In consequence of the superficial descriptions by earlier authors the concepts of several genera are rather vague. Ferris has emphasized that in order
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 4
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.33 (1954) nr.7 p.49
    Publication Date: 2013-03-01
    Description: In seiner Behandlung der Gattung Archon Hb. im Tierreich „Lepidoptera pars I" kommt Bryk am Schluss seiner Betrachtungen zu der Feststellung, dass sich die geographischen „Formen" (subspecies?) in drei Gruppen zusammenfassen lassen. Unbestreitbar sind davon der „bellargus-Kreis" und der Rassenkreis, der die verschiedenen subspecies aus Pontus und Armenien beheimatet. Unklar ist die dritte Gruppe, zu der Bryk A. apollinus Herbst und subsp. thracica Buresch vereinigt. Die Diagnosen, die Bryk für die verschiedenen Rassen gibt, zwingen mich, da ich sein tiefes Wissen von allem und sein Feingefühl für alles, was mit Parnassxus zu tun hat, kenne, zu der Annahme, dass ihm ein zu beschränktes oder unzuverlässiges Material bei seiner Arbeit zu Verfügung gestanden hat. Ich weiss aus eigener Erfahrung, das gerade von Archon ungezählte Exemplare mit falschen Fundortetiquetten im Umlauf sind, oder solche, die den Vermerk e.l. missen. Das letztere ist insofern von Bedeutung, als mir eine grosse Anzahl e.l. Archon — teilweise aus eigener Zucht — vorliegen, die die Berechtigung der Aufstellung geographischer Rassen geradezu lügenzustrafen scheinen. Das Zudhtmaterial zeigt die ganze Variabilitätsbreite der Art und erinnert beispielsweise bei syrischer Herkunft kaum noch an das typische Aussehen von subsp. bellargus Staud. Zucht von Parnassiern ergibt fast stets Tiere, die vom Typus der betreffenden Rasse abweichen, aber sie doch nicht so vollständig verleugnen, wie es bei der grossen Serie Material, Herkunft Beyrouth, in meiner Sammlung der Fall ist. Was ist aber der typische apollinus? Bryk führt als Fundort für den Typus „Umgebung von Aleppo (Insel Kurlak)" auf, gibt aber als Verbreitungsgebiet gleichzeitig „Kleinasien, Mesopotamien" an. Der Begriff „Klein-
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 5
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.33 (1954) nr.8 p.55
    Publication Date: 2013-03-01
    Description: Viele Sammler rümpfen die Nase über die Benennung von Formen. Deren Festhaltung ist indessen wichtig, um einen Überblick über die Variabilitätsbreite einer Species zu geben ; ein weiterer Vorteil der dadurch erhaltenen Übersicht ist, dass er es dem Systematiker leichter macht, die für eine subspecies characteristischen Merkmale innerhalb der Variabilitätsmöglichkeit der species festzulegen. Aus dieser Anschauung heraus benenne ich die folgenden Formen: Luehdorfia puziloi Ersch. cf f. pallida (m.). Grundfarbe des cf weissgelb, wie sie sonst nur ? zeigen. Patria : Sutschanski-Rudnik, Ussuri, ι cf Typus. subsp. coreana Mats. f. fasciata (m.). ι cf mit im Hinterflügel einer continuierlichen Binde vom Wurzelfelde über Mittelzelle nach dem unteren Ende der Hinterrandschwärze. Patria: Umg. Seishin, N. Korea, ι cf Typus. subsp. inexpecta Shelj. f. rubrocatenaria (m.). Die roten Prachtflecken des Hinterflügels sind ungewöhnlich stark entwickelt zu einer breiten Binde, wie sie für subsp. chinensis Leech typisch ist, während bei inexpecta die roten Flecke normal gerade angedeutet sind. Patria: Kanoyama, Japan, ι cf ι ? Typen. Sericinus telamon Donov. f. cellopura (m.). Mittelzellfleck im Vorderflügel oberseits verschwunden, unterseits schwach als f. binaria Bryk erhalten, Endzell fleck stark reduciert. Patria : Mien-shan, Prov. Shansi, ι cf Typus, ι cf Paratypus, ι S Paratypus (subsp. mandschuricus Rosen). subsp. shantungensis M. Hering f. cellopurissima (m.).
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 6
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.33 (1954) nr.2 p.11
    Publication Date: 2013-03-01
    Description: During a short stay at Bangkok on December 3rd, 1953, Professor H. Boschma observed that enormous quantities of minute insects were attracted by lamplight in the hotel of the Royal Dutch Airlines (K.L.M.) "Plaswijk" at the airport Laksi. From the enormous accumulations of these insects around the lamps he collected a sample which he entrusted to me for examination. This sample proved to consist almost entirely of a new species of mayfly which is described in the present paper. Caenis demoulini nov. spec. Female imago. Head and thorax uniformly yellowish brown. Eyes purple-black, prominent. Antennae grey-brown ; median ocellus prominent, colour light brown with a darker edge. Abdomen pale yellowish brown, at the dorsal surface with light browngrey markings, except on the last three tergites. Ventral surface paler, especially the last three segments. Stigmata in or near a faint black or grey spot. Cerci and filum terminale silver-white, rather densely covered with stiff, long, silvery hairs, except at the base of these caudal filaments, where the colour passes into a very light brown, whilst here the hairs abruptly become much shorter, and are placed more densely. Anterior legs grey-brown, median and posterior legs pure white with a very faint yellowish spot at the end of the femora. Wings vitreous, veins light grey, except subcosta and radius, which are dark grey-brown. Area subcostalis very light ferruginous. Measurements: body Q 3.5 mm wing Ç 2.9-3.0 mm
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 7
    facet.materialart.
    Unknown
    In:  Zoologische Verhandelingen (0024-1652) vol.22 (1954) nr.1 p.1
    Publication Date: 2013-03-01
    Description: OLETHREUTINAE (Eucosmidae auct., Eucosminae auct.) Introduction The study of the South Asiatic representatives of the subfamily Olethreutinae of the Tortricidae is difficult on account of various reasons. Our basic knowledge of this group of insects originates from the knowledge of the Palaearctic fauna; unfortunately the taxonomy, and especially the nomenclature of the European Olethreutinae has for a long time been in a deplorable state of confusion and only recent pioneer work along modern lines, chiefly by Obraztsov, leads to some order. Unavoidably this confusion throws a shadow upon the study of the Olethreutinae from other regions than the Palaearctis. Since genital characters are of cardinal importance for the classification of the genera and species of the present group, it is clear that a fundamental revision is necessary, because nobody has ever bothered about these characters before, at least with regard to the South Asiatic fauna. When describing species from that region classic authors, as e.g., Snellen, usually chose a convenient generic name, familiar to the students of the Palaearctic fauna, to attribute them to ; Meyrick, as conveniently, merged many species in one of some four of his enormous genera. Many species of Olethreutinae are ornated with intricate markings that are very difficult to describe in a terse diagnose, as was the habit with those older authors; these descriptions are still more difficult to read! Other species are uniform to such an extent that their identification is impossible without the use of genital characters. Furthermore, Meyrick
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 8
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1954) nr.21 p.233
    Publication Date: 2013-03-01
    Description: In 1950 I received from Mr. D. Hille Ris Lambers a strange Pseudococcid from Java which had been collected by Mr. F. W. Rappard, a senior forestry officer, who regularly collects aphids for Mr. Hille Ris Lambers on his tours of duty. As this insect was a coccid, it was transmitted to me for examination. Its appearance is quite abnormal; the shape of its body reminds one almost of a large mite (fig. 4). The 6-segmented antennae have a dense vestiture of fine hairs, with exception of the 2 first segments which are very short. A tuft of 5 very long setae is present on the top of each of the anal lobes. The ungual digitules are extremely large and very flat. It was only after close study that the insect was recognized as a Pseudococcid. It has 2 pairs of ostioles in the usual position, a circulus on the ventral side of the second abdominal segment, and a few trilocular pores on both sides of the body. As I suspected an abnormal mode of living, I asked Mr. Hille Ris Lambers to write to Java for further particulars, and more material. To comply with this request Mr. Rappard has collected abundant material and communicated his field notes on these insects, which he calls "ant-riders" from their peculiar habit of climbing upon the black ants by which they are closely attended, as soon as these ants are disturbed, to have themselves transported in this way. The material at hand contains 3 different instars which seem to represent first and second stage larvae, and immature adult females. Of the latter stage only 3 specimens are available. Eggs or embryos were not observed in these specimens, but in one of them the oviduct and its exterior opening (one segment behind the posterior ostioles) is faintly visible in the chitinous
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 9
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.33 (1954) nr.11 p.69
    Publication Date: 2013-03-01
    Description: In the course of the year 1954 I received for identification a little Nematoceron belonging to the family Lycoriidae (Sciaridae). After a careful examination of the material and the literature I arrived at the conclusion that my specimens represented a hitherto undescribed species. It belongs to the genus Neosciara Pettey, 1918 (sensu Lengersdorf, 1930 and Frey, 1942). There is some confusion about the naming and delimitation of the genera in the subfamily Lycoriinae. The four most important opinions are : I. Lengersdorf (1930) : Genus Lycoria Meigen, 1800, syn. Saara Meigen, 1803, Gruppe I (no name, veins cu and m with bristles) and Gruppe II Neosciara Pettey, 1918 (cu and m bare). II. Séguy (1940) : Genus Lycoria Meigen, 1800 (cu and m with bristles) and S ciara Meigen, 1803 (veins cu and m bare). III. Frey (1942) : Genus Sciara Meigen, 1803, syn. Lycoria Meigen, 1800 (cu and m with bristles) and genus Neosciara Pettey, 1918 (cu and m without bristles). IV. Frey (1948): Genus Sciara Meigen, 1803 (cu and m with bristles) and genus Bradysia Winnertz, 1867, containing the subgenus Neosciara Pettey, 1918. The character concerning the bristles on the veins cu and m is very important for distinguishing these genera. When summarizing the above opinions we find that the species with bristles on cu and m have been named Lycoria Meigen, 1800 = Sciara Meigen, 1803 (Lengersdorf, 1930) ; Lycoria Meigen, 1800 (Séguy, 1940) ; Sciara Meigen, 1803 = Lycoria Meigen, 1800 (Frey, 1942, 1948). The species lacking setae on the veins cu and m have been named Neosciara Pettey, 1918 (Lengersdorf, 1930, Frey, 1942) ; Sciara
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 10
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1954) nr.22 p.259
    Publication Date: 2013-03-01
    Description: Apterous Aradidae were first brought to the attention of Hemipterists by N. C. E. Miller (Ann. Mag. Nat. Hist. [11] 1: 498-510, 1938). In fact it can be said that this paper with its excellent illustrations was the stimulus for the striking discoveries that have been made in this group in the past decade. The genus Chelonocoris Miller was proposed for a group of seven (actually 8 as is shown below) very large species from Malaya, Borneo, and (as it now appears) India. The present paper was prompted by the discovery in various European museums of several additional species which extend the known range of the genus to Java and Sumatra. In order to place these new species a key was prepared. The first key was based on Miller's types and was written while studying at the British Museum (Natural History) in 1949. A drastic revision of the key was necessitated when the species from Java and Sumatra were added. With the addition of the Sunda Island material certain inconsistencies became evident in the recorded distribution of the previously described species. I am indebted to N. C. E. Miller and W. E. China for their generous aid in straightening out these matters and for checking the revised key. It now appears that two species were included under the name Chelonocoris peregrinus Miller. The type is from Aring which is not in North Borneo but in India. The Malayan specimens represent a new species which is described below and dedicated to N. C. E. Miller in recognition of his pioneer work on apterous Aradidae. Another error which was detected by Miller and China is the drawing of the apex of the mesonotum in Chelonocoris malayensis (fig. 5c). Actually the mesonotum forms a continuous ridge in the female as in the male.
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 11
    Publication Date: 2019-07-11
    Description: A method has been developed for modifying a rocket motor so that its exhaust characteristics simulate those of a turbojet engine. The analysis necessary to the design is presented along with tests from which the designs are evaluated. Simulation was found to be best if the exhaust characteristics to be duplicated were those of a turbojet engine at high altitudes and with the afterburner operative.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-L54I15
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  • 12
    Publication Date: 2019-07-12
    Description: The operational characteristics of a J57-P1 turbojet engine have been investigated at altitudes between 15,000 and 66,000 feet in the Lewis altitude wind tunnel. Included in this study is a discussion of fuel nozzle coking, the altitude operating limits with and without the standard engine control, the compressor surge characteristics, and the engine starting and windmilling characteristics. Severe circumferential turbine outlet temperature gradients which occurred at high altitude as a result of fuel nozzle coking were alleviated by the manufacturer's change in the fuel flow divider schedule and in a nozzle gasket material. Compressor air bleed is required to prevent surge of the outboard compressor in the low engine speed region. The maximum altitude at which the engine was operated without the control was about 66,000 feet at 0.8 flight Mach number and at a reduced engine speed to avoid compressor surge; with the engine control in operation, the altitude operating limit is reduced to approximately 59,000 feet. The maximum altitude at which the engine was started was about 40,000 feet.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE54C31
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  • 13
    Publication Date: 2019-07-12
    Description: A turbine blade with a porous stainless-steel shell sintered to a supporting steel strut has been fabricated for tests at the NACA by Federal-Mogul Corporation under contract from the Bureau of Aeronautics, Department of the Navy. The apparent permeability of this blade, on the average, more nearly approaches the values specified by the NAGA than did two strut-supported bronze blades in a previous investigation. Random variations of permeability in the present blade are substantialy greater than those of the bronze blades, but projected improvements in certain phases of the fabrication process are expected to reduce these variations.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE54D29
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  • 14
    Publication Date: 2019-07-11
    Description: An investigation of a decoupler and a controlled-feathering device incorporated with the YT-56A turboprop engine has been made to determine the effectiveness of these devices in reducing the high negative thrust (drag) which accompanies power failure of this type of engine. Power failures were simulated by fuel cut-off, both without either device free to operate, and with each device free to operate singly. The investigation was made through an airspeed range from 50 to 230 mph. It was found that with neither device free to operate, the drag levels realized after power failures at airspeeds above 170 mph would impose vertical tail loads higher than those allowable for the YC-130, the airplane for which the test power package was designed. These levels were reached in approximately one second. The maximum drag realized after power failure was not appreciably altered by the use of the decoupler although the decoupler did put a limit on the duration of the peak drag. The controlled-feathering device maintained a level of essentially zero drag after power failure. The use of the decoupler in the YT-56A engine complicates windmilling air-starting procedures and makes it necessary to place operating restrictions on the engine to assure safe flight at low-power conditions,
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SA54I09
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  • 15
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.9 p.87
    Publication Date: 2013-03-01
    Description: I have to thank Dr. H. C. Blöte of the Leiden Museum of Natural History for his kindness to entrust me with a number of Carabidae from Indonesia for identification. A few species appear to be new to science; the descriptions follow below. One genus, Horniulus Jedl., is new to the whole of the Malay Archipelago, and another, Bembidion Latr., is new to Sumatra. Of the latter genus there are already a couple of species known from Java. I am much obliged to Mr. E. B. Britton of the British Museum, who carefully compared a few species with specimens in the collections of the British Museum and in Andrewes' collections. The type specimens are in the Leiden Museum. Oxygnathopsis gen. nov. (fig. 1 f) (Andrewes (1938, p. 196) described Oxygnathus javanus upon a single specimen from Java. With regard to the proper genus Andrewes was not absolutely sure because of a number of important differences, but before introducing a new genus he preferred to wait till more material was available. In the sending of the Leiden Museum I found a second specimen, which shows the same characteristics as the specimen described by Andrewes, so that in my opinion a new genus is desirable. The two genera are to be distinguished as follows: 1 (2) Head with the clypeus bisetose, two setae on each side over the eyes, facial carinae and sulci present; prothorax with two lateral setae on each side. Range: Assam and Burma.........Oxygnathus Dej. 2 (1) Clypeus without setae, one supra-orbital seta, the front seta is wanting, no facial Fig. 1. a, Coptodera flavipes sp. n., left elytron; b, Horniulus quadrimaculatus sp. n.,
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 16
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.3 p.31
    Publication Date: 2013-03-01
    Description: Eine Bestimmungssendung des Deutschen Entomologischen Institutes veranlasste mich, die Systematik der asiatischen Coenochilus zu studieren. Die Museen Leiden, Berlin und München und die Herren Frey, Haberäcker, Klapperich und van Nidek stellten mir ihr Material zur Verfügung; Herr Reichert des Museums Dresden und Herr Ruter des Museums Paris gaben bereitwillig Auskunft über Typen ihrer Museen. Ihnen alien sowie den Herren Prof. Dr. Sachtleben, Prof. Dr. Delkeskamp, Dr. C. de Jong, Dr. H. C. Blöte, Dr. Forster, H. Freude, P. Müller und St. von Breuning danke ich bestens für ihre Hilfe. Als Ergebnis meiner Studien veröffentliche ich hier die Beschreibung zweier neuer Arten und des ♂ von C. leopoldi Bourg. sowie eine aus der Arrow'schen Tabelle in der Fauna of British India weiterentwickelte Bestimmungstabelle aller asiatischen Arten. 1. Der Katalog von Junk-Schenkling Pars 72 aus 1921 ist auf Seite 366 f. durch folgende Arten zu ergänzen: assmuthi Wasmann, Wiener Ent. Zeit., vol. 37, 1918, S. 19. bifoveolatus Fairmaire, Ann. Soc. Ent. Fr., 1888, S. 344. leopoldi Bourgoin, Mem. Mus. Roy. H.N. Belg., 1933, Voyage Leopold, vol. IV fasc. 9, Col. II, S. 31. leveillei Nonfried, Berl. Ent. Zeit., 1891, S. 372, der nach Arrow kein Pilinurgus ist. obesus Wasmann, Wiener Ent. Zeit., vol. 37, 1918, S. 21. obscurus Westwood, Tijdsch. v. Ent., vol. 26, 1883, S. 62-65. platycerus Gerstäcker, von S. 368 des Kat. (1883). sumatranus Westwood, Tijdsch. v. Ent., vol. 26, 1883, S. 62-65. uncinatipes Moser, D. Ent. Zeit., 1915, S. 596.
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 17
    Publication Date: 2013-03-01
    Description: Contents ι. Introduction..............I 2. Systematics (a, The correct name of the genus p. 4; b, Diagnostic characters of the species and subspecies p. 6; c, Abbreviations p. 9; d, Key to the species and subspecies p. 10; e, Survey of the species and subspecies p. 11; f, Disregarded specimens p. 30; g, Wilcoxon tests for the difference between certain measurements in allied subspecies p. 31; h, Early stages p. 36; i, The species concept in Nyctalemon p. 37).......... 3. Biology............... 38 4. Distribution.............. 43 5. Evolution............... 46 6. Bibliography.............. 52 1. INTRODUCTION In November 1949 the late Professor Dr. L. J. Toxopeus of Bandung, Java, sent me a specimen of Nyctalemon for identification, but neither with the help of our collection, nor with the current literature did I succeed in ascertaining the correct name of this insect. On the contrary it appeared that, though the described forms of this genus clearly were of different value, viz., partly good species, partly geographical subspecies representing these species in restricted areas, no satisfactory division of the genus into species and subspecies had been given. Thus, Seitz' classification of the known forms into four species of which three are polytypic proved to make no sense. Therefore I resolved to study the genus more closely. In the ensuing correspondence Toxopeus gave me the benefit of his experience by providing references to relevant literature and quotations from
    Keywords: 42.75
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  • 18
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.18 p.203
    Publication Date: 2013-03-01
    Description: COPROMORPHIDAE Meyrick, 1905, Journ. Bombay Nat. Hist. Soc, vol. 16, p. 606. This small family represents a natural group with clearly marked characters, and is easy of descrimination. It inhabits tropical regions of Asia and extends through the Papuan region over the whole Pacific. The last mentioned region might be the country of origin of this group, as genera with peculiar and possibly archaic characters have been recorded from the Pacific Islands; some of those species are distinguished by an exceptionally large size. One of the interesting points with regard to the family is its possible place in the system. The long-ciliate or pectinate antennae, the neuration, and the complicated genital apparatus of the male seem to indicate an affinity with the Tineoidea. The general facies, however, is divergent to some extent, while the presence of a cubital pecten on the hind wings fundamentally discriminates this family from all the Tineoidea sensu stricto. When describing the family, Meyrick suggested that the cubital pecten might point towards an affinity with the Tortricoidea ; this relation, however, is not supported by any other characters. He further surmised that the Copromorphidae would be nearest allied to the Xyloryctidae ; in my opinion this surmise is devoid of any ground. Later Meyrick tried to combine with the Copromorphidae two other groups of "Tineina" that also are in possession of a cubital pecten, viz., the family Orneodidae, and the genus Hypertropha Meyr. The relation of the former with the Copromorphidae, however, is problematic, and deserves further proofs, while Hypertropha has in my opinion nothing in common with the family concerned, except for the
    Keywords: 42.75
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  • 19
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.5 p.43
    Publication Date: 2013-03-01
    Description: Some time ago I was asked to identify a fossil coleopteron which had been found in the drill cuttings of an oil well in the Southern part of Sumatra. As the fossil is only a few millimetres long it may be mentioned as an amazing fact that so small an object has been found during rather rough work like oil drilling. The details of the locality as given by Mr. A. Wright Jr. of the N.V. Standard-Vacuum Petroleum Maatschappij are as follows: "The well is one of our Kaja wells, a wildcat well located 3.3 kilometres N. 300 E. from the northeast edge of the Djirah oilfield. The drill cutting was obtained from a depth of 1930 feet subsea. Although, in drill cuttings, there is a certain measure of uncertainty as to the exact level of derivation, we have sufficient evidence to be sure that the fossil actually derives from this depth. The age is Tertiary-e; it occurs below beds of Baturadja stage age, but 200 feet above a lepidocyclina-bearing horizon. The fossil occurs in a shale interval of a formation which is generally non-fossiliferous; conditions were presumably marine, but either oligotrophe or toxic; the water at the time of deposition was shallow." The fossil is pyritized, dark bronze-greyish in colour. It is nearly free from substrate, though in some crevices a light grey, rather soft, somewhat fattish substance is found which can be taken away rather easily. The fossil was sent to the Rijksmuseum van Natuurlijke Historie at Leiden, mounted in a small box on a slide, pasted to the bottom with tragacanth. During the studies it was left in the small box, and kept in an exsiccator to preserve the fossil against deterioration by atmospheric influence.
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 20
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.32 (1953) nr.6 p.49
    Publication Date: 2013-03-01
    Description: I. Attacus dohertyi dammermani nov. subspec. (Plate II) Large, apex of fore wing moderately produced, general coloration of wings, head, notum including patagia, and abdomen rather light reddish brown, several intersegmental folds between the abdominal tergites blackish. In both wings the terminal area somewhat lighter, more yellowish brown, in apex of fore wing grading into yellowish. Hind wing with the apical area markedly reddish. In fore wing the dark apical spot and red dash weak, submarginal line practically wanting, in hind wing a somewhat undulating submarginal dark line well developed. Postmedian band in both wings strongly serrate, but not bent inwards. Antemedian band in both wings less distinct, not serrate, in fore wing angled on base of v2, in hind wing curved inwards. The vitreous patches in both wings very large, guttiform by having the base curved outwards, the basal angles rounded, and the top elongated and pointed towards the postmedian band. In both wings with two additional vitreous patches which are in fore wing slightly larger than in hind wing. In hind wing the lower patch communicates with the interior black border of the postmedian band. All these spots bordered by a black margin. The interior orange yellow border, so obvious in many dohertyi specimens, is wanting or indicated by some inconspicuous traces only. Underside corresponding with upperside, the outer half very light, as in atlas, but the subterminal markings in both wings practically wanting or obsolete. Lateral markings of abdomen much less developed than in atlas. I ♀, 25 cm, holotype, W. Sumba, IV. 1925, labelled Dammerman, Sumba Exp., in Museum Leiden. 2. THE SPECIES OF THE GENUS Attacus L. IN THE FAR EAST.
    Keywords: 42.75
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  • 21
    Publication Date: 2019-07-12
    Description: A program was undertaken to determine the J73 turbojet engine compressor stall and surge characteristics and combustor blow-out limits enc ountered during transient engine operation. Data were obtained in the form of oscillograph traces showing the time history of several engi ne parameters with changes in engine fuel flow. The data presented in this report are for step and ramp changes in fuel flow at an altitude of 45,000 feet and flight Mach numbers of 0 and 0.8.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE53F30
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  • 22
    Publication Date: 2019-07-12
    Description: The performance of a 13-stage development comressor for the J40-WE-24 engine has been determined at equivalent speeds from 30 to 112 percent of design. The design total-pressure ratio of 6.0 and the design weight flow of 164 pounds per second were not attained, An analysis was conducted to determine the reasons for the poor performance at the design and over-design speed. The analysis indicated that most of the difficulty could be attributed to the fact that the first stage was overcompromised to favor part-speed performance,
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE53D17
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  • 23
    Publication Date: 2019-07-12
    Description: Altitude performance of a YJ71-A-7 turbojet engine, with afterburner inoperative, was determined in the NACA Lewis altitude wind tunnel over a wide range of flight conditions. Engine speed and exhaust-nozzle area were controlled independently during this investigation. The variation of corrected values of air flow, net thrust, and fuel flow with corrected engine speed was not defined by a single curve with changes in altitude at given flight Mach number. Changes in altitude had very little effect on minimum specific fuel consumption at altitudes up to 45,000 feet. There is one exhaust-nozzle schedule that is nearly optimum for all flight conditions. Performance calculated from pumping characteristics agreed with experimental values and can therefore be used to extend engine performance data.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E53E13
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  • 24
    Publication Date: 2019-07-12
    Description: A program was undertaken to determine the J73 turbojet engine compressor stall and surge characteristics and combustor blow-out limits encountered during transient engine operation. Data were obtained in the form of oscillograph traces showing the time history of several engine performance parameters with changes in engine fuel flow. The data presented in this report are for step changes in fuel flow at an altitude of 35,000 feet, at flight Mach numbers of 0.3, 0.8, and 1.2, and at several engine-inlet temperatures,
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE53F29
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  • 25
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1952) nr.16 p.165
    Publication Date: 2013-03-01
    Description: When revising the genera of Indo-Australian and Papuan Tortricidae (1939) the author was very much in doubt as to the systematic position of the genus Diactenis Meyrick, 1907, referred before to the Tortricidae. It did not fit in that family, neither could it be successfully transferred to any other Tortricoid family known. Through lack of further data the author decided at last to transfer Diactenis to the family Chlidanotidae; the necessity of its removal from the Tortricidae being only too evident. This decision, however, was not very happy, as Diactenis was neither at its proper place in the Chlidanotidae. In the same year (1939) the late T. Bainbrigge Fletcher suggested to the author (in litt.) to erect for Diactenis a new family. Although this seemed a reasonable solution, we esteemed such an action to be premature, our information on the possible congeners of Diactenis being insufficient at that time. Instead, however temporarily, Diactenis was transferred back to the Tortricidae; but at the same time attention was drawn to the close correlation of that genus with two others (1941). Soon afterwards still more new forms of the Diactenis relationship continued coming to our notice, and the conception of this new family began to take shape. It materialized after our study of the excellent collection of Microlepidoptera, brought together by our lamented friend, the late Dr. L. J. Toxopeus, during the Third Archbold Expedition to New Guinea. The results of this study will be published soon. Meanwhile we are satisfied that the information collected during these twelve years is entirely sufficient for carrying into effect the so long
    Keywords: 42.75
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  • 26
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1952) nr.24 p.259
    Publication Date: 2013-03-01
    Description: A study of the collection of Dermaptera in the Rijksmuseum van Natuurlijke Historie at Leiden has been made by the author during the years 1942 and 1943, but publication of the results had to be postponed for several years on account of various difficulties arising during and since the war. These investigations yielded some interesting results, including the descriptions of several new species. It is intended to publish these descriptions in the near future after a study of the literature of the group that has appeared since 1943. Of the subfamily Diplatyinae the material of the Leiden Museum contains specimens of two forms that proved to belong to hitherto undescribed species. Together with other representatives of this subfamily these specimens were sent to Dr. W. D. Hincks of the Manchester Museum, for comparison with the material that formed the basis for his nearly completed revision of the group. Of the two forms referred to above, one appeared to be conspecific with a species to be described by Dr. Hincks in the near future, the other is described in the present paper, in order that notes on this species may be incorporated into the revision of the group. Diplatys sumatranus nov. spec. 1 ♂, Air Njuruk, Dempu, Sumatra, 1400 m, VIII 1916, coll. E. Jacobson. The present specimen is small and slender, of the usual general appearance in this genus (see fig. 1). Colouration: the head and the prozona of the pronotum are castaneous; the same colour, though less dark generally, is shown by the median part of the metazona, the elytra, a band along the outer margins of the wing-scales, Fig. 1. Diplatys sumatranus nov. spec. af habitus of male, and end of abdomen in lateral
    Keywords: 42.75
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  • 27
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1952) nr.23 p.251
    Publication Date: 2013-03-01
    Description: In the course of the later years a rather large number of specimens of various groups of insects from New Guinea were among the acquisitions of the Rijksmuseum van Natuurlijke Historie. Shortly after the war the collections made by Professor H. Boschma, during his visit to the Wissel Lakes in 1939 as the zoologist of the expedition organized by the Royal Netherlands Geographical Society (Koninklijk Nederlandsch Aardrijkskundig Genootschap), arrived safely from Bogor (Java) where they had to stay during the German occupation of the Netherlands. Quite recently we obtained the first captures made by Dr. L. D. Brongersma in various places in and near New Guinea. From both collections a number of new and interesting Heteroptera is to be described. A few Oncomerini, belonging to the genera Lyramorpha and Agapophyta, are the subject of the present note. Lyramorpha Subgenus Lyrodes Of the subgenus Lyrodes two new species were collected at and near the Wissel Lakes. The first, which I will name Lyramorpha (Lyrodes) edulis nov. spec.*) (figs. 1-2), shows no definite spot or patch on the corium; the basal corners of the scutellum are yellowish, medially from this yellow spot a distinct dark point is to be seen, except in specimens that are more or less immature. The general colour is more or less castaneous, with inVentral views of the ultimate abdominal segments of: fig. I, Lyramorpha (Lyrodes) edulis ♂ ; fig. 2, Lyramorpha (Lyrodes) edulis ♀ ; fig. 3, Lyramorpha (Lyrodes) plagifer ♂ ; fig. 4, Lyramorpha (Lyrodes) plagifer ♀ ; fig. 5, Lyramorpha (Diploxiphus) maculifer ♂ ; fig. 6, Lyramorpha (Diploxiphus) maculifer ♀.
    Keywords: 42.75
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  • 28
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1952) nr.20 p.225
    Publication Date: 2013-03-01
    Description: The present paper constitutes a report on the Machilidae and Lepismatidae collected by Dr. C. O. van Regteren Altena in the Canary Islands in the spring of 1947. We are much obliged to Dr. van Regteren Altena for allowing us to study these interesting specimens. The first notice on Thysanura from the Canary Islands seems to be the mentioning of Machilis maritima by Lucas (1836-44). Unfortunately it is quite impossible nowadays to identify that species as understood by Lucas. Ridley (1881) mentions three species from the Canary Islands, viz., Lepisma saccharina L., from Tenerife and Gran Canaria; Lepisma mauritanica Lucas, from Las Palmas (Gran Canaria) and Lepisma eatonii Ridley, from Tenerife. L. saccharina has apparently not been found again on the Islands; anyhow we do not see any reason to doubt its presence there. Lepisma mauritanica, actually included in the genus Ctenolepisma, is a species that is rare as well as very difficult to identify; Ridley's specimens were most probably nothing else but dark Ctenolepisma lineata, a species common in the Islands. Finally Lepisma eatonii, whose correct name should be Ctenolepisma lineata eatonii, is nothing more than a colour form of Ctenolepisma lineata, which may not deserve even subspecific rank. Escherich (1905) also mentions Ctenolepisma lineata eatonii from Tenerife. Silvestri (1940) gives the first record for Lepisma myrmecobia Silvestri from the Islands (Gran Canaria and Tenerife). Wygodzinsky (1941) described Dilta insulicola from Tenerife. In the present paper an additional species of Dilta, Dilta altenai sp. n. is described from Tenerife, and several of the formerly known species of
    Keywords: 42.75
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  • 29
    facet.materialart.
    Unknown
    In:  Zoologische Verhandelingen (0024-1652) vol.16 (1952) nr.1 p.1
    Publication Date: 2013-03-01
    Description: The Oriental bees of the genus Ceratina Latr. are difficult to identify. Until now our knowledge of these insects consisted mainly of a considerable number (about 90) of isolated descriptions, scattered through several scientific journals. Most of these descriptions are based on colour characters and although these are certainly not without taxonomic value, they must be used with great care on account of their intra-specific variability. The structural and sculptural characters which are much more reliable for distinguishing the species have thus far not received sufficient attention. There exist a few keys, dealing with the species occurring in certain parts of the region, but none of these contains more than 11 species and the characters used are often of doubtful taxonomic value. An attempt to identify a large number of species collected in Indonesia, mainly in Java, by Dr. and Mrs. Lieftinck, my wife and myself, soon demonstrated the necessity of a revision of the Ceratina species described from this and other parts of the Oriental region. It would have been completely impossible to recognize the majority of these species with sufficient certainty from their descriptions. Fortunately I had an opportunity to study much authentic material. In September 1951 I examined the types of several species described by Smith, Cameron, and Cockerell in the collections of the British Museum (Natural History) and the Oxford University Museum ; some additional types, preserved in the Rothney collection in the latter Museum, were kindly sent to me for study at a later date. The U.S. National Museum sent me a very interesting collection of oriental Ceratina, containing several species identified by Cockerell as well
    Keywords: 42.75
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  • 30
    Publication Date: 2019-07-12
    Description: A theoretical method for evaluating the stability characteristics and the amplitude and the frequency of pulsation of ram-jet engines without heat addition is presented herein. Experimental verification of the theoretical results are included where data were available. Theory and experiment show that the pulsation amplitude of a high mass-flow-ratio diffuser having no cone surface flow separation increases with decreasing mass flow. The theoretical trends for changes in amplitude, frequency, and mean-pressure recovery with changes in plenum-chamber volume were experimentally confirmed. For perforated convergent-divergent-type diffusers, a stability hysteresis loop was predicted on the pressure-recovery mass-flow-ratio curve. At a given mean mass-flow ratio, the higher.value of mean pressure recovery corresponded to oscillatory flow in the diffuser while the lower branch was stable. This hysteresis has been observed experimentally. The theory indicates that for a ram-jet engine of given diameter, the amplitude of pulsation of a supersonic diffuser is increased by decreasing the relative size of the plenum chamber with respect to the diffuser volume down to a critical value at which oscillations cease. In the region of these critical values, the stable mass-flow range of the diffuser may be increased either by decreasing the combustion chamber volume or by increasing the length of the diffuser.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E52I24
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  • 31
    Publication Date: 2019-07-11
    Description: An investigation was conducted at simulated high-altitude flight conditions to evaluate the use of compressor evaporative cooling as a means of turbojet-engine thrust augmentation. Comparison of the performance of the engine with water-alcohol injection at the compressor inlet, at the sixth stage of the compressor, and at the sixth and ninth stages was made. From consideration of the thrust increases achieved, the interstage injection of the coolant was considered more desirable preferred over the combined sixth- and ninth-stage injection because of its relative simplicity. A maximum augmented net-thrust ratio of 1.106 and a maximum augmented jet-thrust ratio of 1.062 were obtained at an augmented liquid ratio of 2.98 and an engine-inlet temperature of 80 F. At lower inlet temperatures (-40 to 40 F), the maximum augmented net-thrust ratios ranged from 1.040 to 1.076 and the maximum augmented jet-thrust ratios ranged from 1.027 to 1.048, depending upon the inlet temperature. The relatively small increase in performance at the lower inlet-air temperatures can be partially attributed to the inadequate evaporation of the water-alcohol mixture, but the more significant limitation was believed to be caused by the negative influence of the liquid coolant on engine- component performance. In general, it is concluded that the effectiveness of the injection of a coolant into the compressor as a means of thrust augmentation is considerably influenced by the design characteristics of the components of the engine being used.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E52F20
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  • 32
    Publication Date: 2019-07-12
    Description: The stator-blade angles in the twelfth to fifteenth stages of a 16-stage high-pressure-ratio axial-flow compressor were decreased 3 deg The over-all performance of this compressor is compared with the performance of the same compressor with standard blade angles. The matching characteristics of the modified compressor and a two-stage turbine were also obtained and compared with those of the compressor with the original blade angles and the same turbine.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E51L03
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  • 33
    Publication Date: 2019-07-12
    Description: An investigation to increase the compressor surge-limit pressure ratio of the XJ40-WE-6 turbojet engine at high equivalent speeds was conducted at the NACA Lewis altitude wind tunnel. This report evaluates the compressor modifications which were restricted to (1) twisting rotor blades (in place) to change blade section angles and (2) inserting new stator diaphragms with different blade angles. Such configuration changes could be incorporated quickly and easily in existing engines at overhaul depots. It was found that slight improvements in the compressor surge limit were possible by compressor blade adjustment. However, some of the modifications also reduced the engine air flow and hence penalized the thrust. The use of a mixer assembly at the compressor outlet improved the surge limit with no appreciable thrust penalty.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE52G03
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  • 34
    Publication Date: 2019-07-12
    Description: An investigation of the effect of inlet pressure, corrected engine speed, and turbine temperature level on turbine-inlet gas temperature distributions was conducted on a J40-WE-6, interim J40-WE-6, and prototype J40-WE-8 turbojet engine in the altitude wind tunnel at the NAC.4 Lewis laboratory. The engines were investigated over a range of simulated pressure altitudes from 15,000 to 55,000 feet, flight Mach numbers from 0.12 to 0.64, and corrected engine speeds from 7198 to 8026 rpm, The gas temperature distribution at the turbine of the three engines over the range of operating conditions investigated was considered satisfactory from the standpoint of desired temperature distribution with one exception - the distribution for the J40-WE-6 engine indicated a trend with decreasing engine-inlet pressure for the temperature to exceed the desired in the region of the blade hub. Installation of a compressor-outlet mixer vane assembly remedied this undesirable temperature distribution, The experimental data have shown that turbine-inlet temperature distributions are influenced in the expected manner by changes in compressor-outlet pressure or mass-flow distribution and by changes in combustor hole-area distribution. The similarity between turbine-inlet and turbine-outlet temperature distribution indicated only a small shift in temperature distribution imposed by the turbine rotors. The attainable jet thrusts of the three engines were influenced in different degrees and directions by changes in temperature distributions with change in engine-inlet pressure. Inability to match the desired temperature distribution resulted, for the J40-WE-6 engine, in an 11-percent thrust loss based on an average turbine-inlet temperature of 1500 F at an engine-inlet pressure of 500 pounds per square foot absolute. Departure from the desired temperature distribution in the Slade tip region results, for the prototype J40-WE-8 engine, in an attainable thrust increase of 3 to 4 percent as compared with that obtained if tip-region temperature limitations were observed.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E52H06
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  • 35
    Publication Date: 2019-07-10
    Description: An investigation was made of the performance of nine conical cooling-air ejectors at primary jet pressure ratios from 1 to 10, secondary pressure ratios to 4.0, and a temperature ratio of unity. This phase of the investigation was limited to conical ejectors having shroud exit to primary nozzle exit diameter ratios of 1.06 and 1.40, with several spacing ratios for each. The experimental results indicated that the pumping range and amount of cooling-air flow obtained with a 1.06 diameter ratio ejector were relatively small for cooling purposes but that the maximum possible thrust loss, which occurred with no secondary flow, was only 7 percent of convergent nozzle thrust. The 1.40 diameter ratio ejector produced a large cooling air flow and showed a possible thrust loss of 29.5 percent with no cooling air flow. Thrust gains were attained with ejectors of both diameter ratios at secondary pressure ratios greater than 1.0. The limiting primary pressure ratio below which an ejector can operate at a specific secondary pressure ratio (cut-off point) may be estimated for various flight conditions from data contained herein.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E52F26
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  • 36
    Publication Date: 2014-07-15
    Description: An experimental investigation was conducted to determine the cooling effectiveness of a wide variety of air-cooled turbine-blade configurations. The blades, which were tested in the turbine of a - commercial turbojet engine that was modified for this investigation by replacing two of the original blades with air-cooled blades located diametrically opposite each other, are untwisted, have no aerodynamic taper, and have essentially the same external profile. The cooling-passage configuration is different for each blade, however. The fabrication procedures were varied and often unique. The blades were fabricated using methods most suitable for obtaining a small number of blades for use in the cooling investigations and therefore not all the fabrication procedures would be directly applicable to production processes, although some of the ideas and steps might be useful. Blade shells were obtained by both casting and forming. The cast shells were either welded to the blade base or cast integrally with the base. The formed shells were attached to the base by a brazing and two welding methods. Additional surface area was supplied in the coolant passages by the addition of fins or tubes that were S-brazed. to the shell. A number of blades with special leading- and trailing-edge designs that provided added cooling to these areas were fabricated. The cooling effectiveness and purposes of the various blade configurations are discussed briefly.
    Keywords: Aircraft Propulsion and Power
    Type: REPT-2203 , NACA-RM-E51E23
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  • 37
    Publication Date: 2014-07-15
    Description: Tests of two propellers having two blades and differing only in the inboard pitch distribution were made in the Langley 8-foot highspeed tunnel to determine the effect of inboard pitch distribution on propeller performance. propeller was designed for operation in the reduced velocity region ahead of an NACA cowling; the inboard pitch distribution of the modified propeller was increased for operation at or near free-stream velocities, such as would be obtained in a pusher installation. conditions covering climb, cruise, and high-speed operation. Wake surveys were taken behind the propellers in order to determine the distribution of thrust along the blades and to aid in the analysis of the results. Test results showed that the modified propeller was about 2.5 percent less efficient for a typical climb condition at all altitudes, 2 percent more efficient for one cruise condition, and 5 percent more efficient for high-speed operation. speed condition, the modified propeller showed a 6-percent loss in efficiency due to compressibility; whereas the original propeller showed an 11-percent efficiency loss due to compressiblity. The lower compressibility loss for the modified propeller resulted from the fact that the inboard sections of this propeller could operate at increased thrust loading after compressibility losses had occurred at the outboard sections.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-TN-2268
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  • 38
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1951) nr.13 p.129
    Publication Date: 2013-03-01
    Description: Records of cave-dwelling Lepidoptera are scarce in comparison with those in other orders of Insects, e.g., Coleoptera, of which even a whole subfamily (Silphidae, Bathysciinae) is in a most remarkable way adapted to this peculiar habitat. In the group of the so-called Microlepidoptera we could find examples of some eight species only, belonging to different families. Apparently none of them is a true cave-dweller, i. e., a permanent resident of caves and really adapted to life in total darkness. Crypsithyris spelaea Meyrick, 1908 (Tinaeidae) only has been regarded as an exception. This species has been described from a large cave in Moulmein, Burma, and originally was reported as "being practically bleached or colourless", but with normally developed eyes and wings (Meyrick, 1908, p. 399). Later on better material has been collected at the same locality, and this time the moth appeared to be not quite colourless (Meyrick, 1916, pp. 602-603). It remains uncertain, therefore, whether there is question of any adaptation to cave-life and whether this species can be regarded as an "obligate cavernicole,, insect, the more so as larvae of closely allied species of this genus have been found living in the open, in portable cases on lichens covering rocks. Furthermore we could find reference to three species of the genus Tinaea: T. antricola Meyr., 1924, and T. pyrosoma Meyr., 1924, both from Siju Caves, Assam, and T. palaechrysis Meyr., 1929, from Batu Caves, Selangor (Malaya). Of the latter was said that it "belongs to the typically unicolorous yellow group, but has probably acquired fuscous colouring as an adaptation to cave life; it may therefore be a true cave-dweller, possibly restricted to these particular caves" (Meyrick, 1929, p. 375). Afterwards, however, Dam-
    Keywords: 42.75
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  • 39
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1951) nr.15 p.149
    Publication Date: 2013-03-01
    Description: I. Grouping of European species of the genus Astata Latr. It is not my intention to anticipate in this paper a subgeneric division of the genus Astata 1). For the purpose of such division, it would be necessary to investigate more non-European material than at present is at my disposal. But at first view it seems to me that the European species may be divided into four distinct groups, which may be separated with the key given below. Two of the proposed groups (the stigma-group and the tricolor-group) form part of the subgenus Dryudella Spinola, as this subgenus has generally been understood; nevertheless, the differences between these two groups, namely in the shape of the clypeus and, in the females, in the habitus, seem to justify separating them; although, investigation of allied non-European species might make it necessary to adapt or to modify the key to the groups. Eventually, the possibility that non-European intermediate forms will make the separations untenable cannot be absolutely excluded. A decision about the taxonomic rank of the proposed groups, therefore, must be postponed. Spinola (1843, P- 135), erecting the genus or subgenus Dryudella ("une nouvelle coupe, qu'on appellera genre ou sous-genre, selon les principes qu'on aura adoptes dans la nomenclature binominale"), based the "nouvelle coupe" on the wing venation of "Dimorpha cincta Perris" and separated it from "Dimorpha" 1) "par la troisieme cubitale, lunulee comme dans les "Lyrops" 2) et par la premiere nervure recurrente, qui s'anastomose avec la nervure transversale qui separe la premiere de la seconde cubitale". However, in these critical features, Spinola was incorrect in several respects. Even excluding stigma and its near allies from Dryudella (Spinola himself never
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 40
    Publication Date: 2019-06-28
    Description: A comparison of the operating characteristics of 75-millimeter-bore (size 215) cylindrical-roller one-piece inner-race-riding cage-type bearings was made using a laboratory test rig and a turbojet engine. Cooling correlation parameters were determined by means of dimensional analysis, and the generalized results for both the inner- and outer-race bearing operating temperatures are compared for the laboratory test rig and the turbojet engine. Inner- and outer-race cooling-correlation curves were obtained for the turbojet-engine turbine-roller bearing with the same inner- and outer-race correlation parameters and exponents as those determined for the laboratory test-rig bearing. The inner- and outer-race turbine roller-bearing temperatures may be predicted from a single curve, regardless of variations in speed, load, oil flow, oil inlet temperature, oil inlet viscosity, oil-jet diameter or any combination of these parameters. The turbojet-engine turbine-roller-bearing inner-race temperatures were 30 to 60 F greater than the outer-race-maximum temperatures, the exact values depending on the operating condition and oil viscosity; these results are in contrast to the laboratory test-rig results where the inner-race temperatures were less than the outer-race-maximum temperatures. The turbojet-engine turbine-roller bearing, maximum outer-race circumferential temperature variation was approximately 30 F for each of the oils used. The effect of oil viscosity on inner- and outer-race turbojet-engine turbine-roller-bearing temperatures was found to be significant. With the lower viscosity oil (6x10(exp -7) reyns (4.9 centistokes) at 100 F; viscosity index, 83), the inner-race temperature was approximately 30 to 35 F less than with the higher viscosity oil (53x10(exp -7) reyns (42.8 centistokes) at 100 F; viscosity index, 150); whereas the outer-race-maximum temperatures were 12 to 28 F lower with the lower viscosity oil over the DN range investigated.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E51I05
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  • 41
    Publication Date: 2019-07-12
    Description: At the request of the Bureau of Aeronautics, Department of the Navy, an investigation of the Westinghouse XJ34-WE-32 turbojet engine is being conducted in the NACA Lewis altitude wind tunnel to determine the steady-state and transient operating characteristics of the controlled and uncontrolled engine at various altitudes and ram pressure ratios. As part of this program, transient performance data that illustrate the operation of the engine is obtained in the form of oscillographic traces. Similar data for engine operation i n the afterburning range, covering a range of throttle settings from the minimum value giving rated speed (throttle position, 72 degrees) to full afterburning (throttle position, ll0 degrees), is presented herein. These data thus serve to indicate the transient characteristics of the engine when the throttle is advance into, withdrawn from, and moved within the afterburning range in a stepwise manner, as well as the steady-state stability of the engine during afterburning .
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE50L29
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  • 42
    Publication Date: 2019-07-12
    Description: An investigation was conducted at the NACA Lewis laboratory to determine whether simulated porous gas-turbine blades fabricated by the Eaton Manufacturing Company of Cleveland, Ohio would be satisfactory with respect to coolant flow for application in gas-turbine engines. These blades simulated porous turbine blades by forcing the cooling air onto the blade surface through a large number of chordwise openings or slits between laminations of sheet metal or wire. This type of surface has a finite number of openings, whereas a porous surface has an almost infinite number of smaller openings for the coolant flow. The investigation showed that a blade made of sheet-metal laminations stacked on a support member that passed up through the coolant passage was completely unsatisfactory because of extremely poor coolant flow distribution over the blade surface. The flow distribution for two wire-wound blades was more uniform, but the pressure drop between the coolant supply pressure and the local pressure on the outside of the blades was too low by a factor ranging from 3 to 3.5 for the required coolant flow rates. The pressure drop could be increased by forcing the wires closer together during blade fabrication.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE51C13
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  • 43
    Publication Date: 2019-07-12
    Description: This report summarizes the effects of fuel volatility and engine design variables on the problem of starting gas-turbine engines at sea-level and altitude conditions. The starting operation for engines with tubular combustors is considered as three steps; namely, (1) ignition of a fuel-air mixture in the combustor, (2) propagation of flame through cross-fire tubes to all combustors, and (3) acceleration of the engine from windmilling or starting speed to the operating speed range. Pertinent data from laboratory researches, single-combustor studies, and full-scale engine investigations are presented on each phase of the starting problem.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE51B02
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  • 44
    Publication Date: 2019-07-12
    Description: A .General Electric fuel and torque regulator was tested in conjunction with a T31-3 turbine-propeller engine in the sea-level static test stand at the NACA Lewis laboratory. The engine and control were operated over the entire speed range: 11,000 rpm, nominal flight idle, to 13,000 rpm, full power. Steady-state and transient data were recorded and are presented with a description of the four control loops being used in the system. Results of this investigation indicated that single-lever control operation was satisfactory under conditions of test. Transient data presented showed that turbine-outlet temperature did overshoot maximum operating value on acceleration but that the time duration of overshoot did not exceed approximately 1 second. This temperature limiting resulted from a control on fuel flow as a function of engine speed. Speed and torque first reached their desired values 0.4 second from the time of change in power-setting lever position. Maximum speed overshoot was 3 percent.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE1H20
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  • 45
    Publication Date: 2019-07-11
    Description: Strain-gages were used to measure blade vibrations causing failures in the third stage of a production 11-stage axial-flow compressor. After the serious third-stage vibration was detected, a series of investigations were conducted with second-stage vane assemblies of varying angles of incidence. Curves presented herein show the effect of varying the angle of incidence of second-stage vane assembly on third-stage rotor-blade vibration amplitude and engine performance. A minimum vibration amplitude was obtained without greatly affecting the engine performance with a second-stage vane assembly of 9deg. greater angle of incidence than the assembly normally furnished with the engine.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE51F08
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  • 46
    Publication Date: 2019-07-12
    Description: Component data on the J35-A-23 compressor and two-stage turbine were used to determine the problems in matching the two units for operatio n in a turbojet engine. Possible operating regions were determined an d an equilibrium operating line was also determined for the assumed c onditions of zero flight speed and a jet nozzle area approximately 5. 5 percent greater than the wide-open nozzle area.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E51H15
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  • 47
    Publication Date: 2019-07-11
    Description: An investigation of the altitude performance characteristics of an Allison J35-A-17 turbojet engines have been conducted in an altitude chamber at the NACA Lewis laboratory. Engine performance was obtained over a range of altitudes from 20,000 to 60,000 feet at a flight Mach number of 0.62 and a range of flight Mach numbers from 0.42 to 1.22 at an altitude of 30,000 feet. The performance of the engine over the range investigated could be generalized up to an altitude of 30,000 feet. Performance of the engine at any flight Mach number in the range investigated can be predicted for those operating condition a t which critical flow exits in the exhaust nozzle with the exception of the variables corrected net thrust, and net-thrust specific fuel consumption.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-E50I15
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  • 48
    Publication Date: 2019-07-11
    Description: This report presents a compilation of static sea-level data on existing or designed American and British axial-flow turbojet engines in terms of basic engine parameters such as thrust and air flow. In the data presented, changes in the over-U engine performance with time sre examined as well as the relation of the various engine parameters to each other.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-51K29
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  • 49
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-08-13
    Description: The performance of a jet power plant consisting of a compressor and a turbine is determined by the characteristic curves of these component parts and is controllable by the characteristics of the compressor and the turbine i n relation t o each other. The normal. output, overload, and throttled load of the Jet power plant are obtained on the basis of assumed straight-line characteristics.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-TM-1258
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  • 50
    Publication Date: 2014-07-15
    Description: A literature survey was conducted to determine the relation between aircraft ignition sources and inflammables. Available literature applicable to the problem of aircraft fire hazards is analyzed and, discussed herein. Data pertaining to the effect of many variables on ignition temperatures, minimum ignition pressures, and minimum spark-ignition energies of inflammables, quenching distances of electrode configurations, and size of openings incapable of flame propagation are presented and discussed. The ignition temperatures and the limits of inflammability of gasoline in air in different test environments, and the minimum ignition pressure and the minimum size of openings for flame propagation of gasoline - air mixtures are included. Inerting of gasoline - air mixtures is discussed.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-TN-2227
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  • 51
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1950) nr.7 p.67
    Publication Date: 2013-03-01
    Description: On trouvera ici l'étude d'une partie des Hepialidae du Musée de Leiden que le Dr. van Regteren Altena a bien voulu nous confier pour étude, ce dont le remercions vivement. Nous y avons ajouté l'étude de quatre espèces du British Museum (N.H.) et une du Museum de Paris. HÉPIALIDES DE LA NOUVELLE GUINÉE On connait quelques Hépiales décrites de Nouvelle Guinée. Elles appartiennent au magnifique genre Oenetus H.S. et au genre Oxycanus Walk, (s.l.). On trouvera ici l'étude de quelques espèces appartenant à ce dernier genre. Grace à l'amabilité de Mr. J. D. Bradley du British Museum (N.H.), que nous remercions, les quatre espèces décrites par Joicey et Talbot (1917) ont pu etre étudièes. Paraoxycanus n. gen. Ce nouveau genre, très proche du genre Oxycanus Walk, ne comprend jusqu'à présent, à notre connaissance, que quelques Hépiales néo-guinéennes classées jadis dans le genre Porina Walk. Tindale (1936) a montré que ce dernier nom était préoccupé et que, de plus, il était synonyme d'Oxycanus Walk. L'espèce type de ce genre a été fixée par Kirby (1892) comme étant australis Walk. Ayant trouvé que l'armure génitale male des espèces étudiées était différente de celle d'australis Walk. nous devons créer ce genre. On pourra comparer les figures 7 et 8. La nervation est la meme que celle du genre Oxycanus Walk. La patte prothoracique porte un strigil. Les antennes ne sont pas fortement bipectinees, mais seulement avec un petit bouquet de soies a l'apex de chaque article. Enfin dans rarmure genitale male il existe une nette difference dans le vinculum, dans les relations de celui-ci avec la membrane mtersegmentaire
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 52
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1950) nr.4 p.39
    Publication Date: 2013-03-01
    Description: The genus Podolestes, as far as at present known, is confined to the Malaysian subregion of the Indo-Australian Archipelago. Descriptions and drawings of structural details of four species are to be found in two of the writer's previous papers on Malaysian dragonf lies, viz.: New and little known Odonata of the Oriental and Australian Regions. Treubia, 15, 1935: 177-183, fig. 1-3. Descriptions and records of South-East Asiatic Odonata (II). Ibid. 17, 1940: 347-350, fig. 4-5. The species of Podolestes have been found in marshes and along muddy creeks flowing through wooded areas in low country. Owing to their retiring habits the insects are but seldom encountered and all species are rare in collections. Little or nothing is known of their life-histories, and the larva is still unknown. The six known members of the genus, two of which are here described for the first time, may be distinguished by the following Key to the species. 1. Dorsum of thorax uniform metallic bronzy black. Labrum, mandibles and genae shiny black. Ante-alar triangles bronzy-black, unmarked. Nervure Ac situated much nearer Ax2 than Ax1; nervure Ab complete, meeting Ac at the wing-margin. Quadrilateral short, markedly widened distally, costal and distal sides approximately equal in length in fore wing. Three to four postquadrangular antenodal cells. Male anal appendages of slender build, blackish in colour; superior pair a trifle longer than the inferiors; apex of inf. app. expanded, truncated and slightly notched 2. —. Dorsum of thorax with two pairs of light-coloured spots on mesepisternum, and sides with an oblique band extending from below the spiracle upwards as far as the dorsal
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
    Type: Article / Letter to the editor
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  • 53
    facet.materialart.
    Unknown
    In:  Zoologische Verhandelingen (0024-1652) vol.11 (1950) nr.1 p.1
    Publication Date: 2013-03-01
    Description: CONTENTS Introduction............... 3 Systematic survey of the Limacidae of the central and western Canary Islands 5 Biogeographical notes on the Limacidae of the Canary Islands . . . . 21 Alphabetical list of the persons who collected or observed Limacidae in the Canary Islands.............. 31 Literature............... 32 INTRODUCTION In the spring of 1947 I was so fortunate as to join for some 9 weeks the Danish Zoological Expedition to the Canary Islands. During my stay I collected materials for the Rijksmuseum van Natuurlijke Historie at Leiden, paying special attention to the land- and freshwater Mollusca. This paper contains the first results of the examination of the Mollusca collected. My Danish friends Dr. Gunnar Thorson and Dr. Helge Volsøe generously put at my disposal the non-marine Mollusca they collected during their stay in the Canaries. When the material has been worked up, duplicates will be deposited in the Zoological Museum at Copenhagen. I am indebted to several persons who helped me in various ways in the investigations here published. Prof. Dr. N. Hj. Odhner (Stockholm) very kindly put at my disposal a MS list of all the Mollusca of the Canary Islands and their distribution, which he had compiled for private use. Mr. Hugh Watson (Cambridge) never failed to help me by examining or lending specimens, and in detailed letters gave me the benefit of his great experience. During my stay in Paris in March 1950 Dr. G. Ranson and Dr. A. Franc put at my disposal for examination the Canarian slugs present in the Muséum
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 54
    facet.materialart.
    Unknown
    In:  Zoologische Mededelingen (0024-0672) vol.31 (1950) nr.6 p.63
    Publication Date: 2013-03-01
    Description: Part of the butterfly collection of Mr. P. Zondervan, who died in a Japanese camp, was saved from destruction during the Japanese occupation and the post-war troubles and finally came into my hands. The material is for the greater part still in an excellent condition and contains many interesting forms. The number of specimens is small, as it was Mr. Zondervan's habit to mount only one pair of any new species he collected. The bulk so remained in papers and these all got lost. Here follows an account of some interesting Pieridae. Appias (paulina) urania (Wall.) Tachyris urania, Wallace, "Eastern Pieridae", Trans. ent. Soc. 6 (3) 3 (1867), Tondano, mountains of N. Celebes (♂). Appias urania, Martin, D. ent. Zeits. Iris, 91, 1919. 1 ♂, Tondano, 17.7.1939, 1 ♀, Tondano, 9.1937; 1 ♂, var. albata Hopff., Tondano, 22.12.1939. The ♀ seems to be very rare, though it shows up in rather good numbers in other places of the paulina area in the favourable season, which is at the end of the wet monsoon. It would have been waste of paper to mention these captures, were it not that Mr. Zondervan captured another ♂ specimen of the paulina complex which is so deviating from the above that anybody first seeing it would conceive it as belonging to a distinct species. It represents the leis (Hbn.) group of paulina (Cram.) in the Celebes district, just as urania Wall., together with some local races from the Lesser Sunda Is., is the general representative in the Archipelago. In other words, there has been some overlapping in Celebes, and one more species duplex must be added to the
    Keywords: 42.75
    Repository Name: National Museum of Natural History, Netherlands
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  • 55
    Publication Date: 2019-07-11
    Description: Performance data obtained with recording oscillographs are presented to show the transient response of the General Electric Integrated Electronic Control operating on the J47 RXl-3 turbo-Jet engine over a range of altitudes from 10,000 to 45,000 feet and at ram pressure ratios of 1.03 and 1.4. These data represent the performance of the final control configuration developed after an investigation of the engine transient behavior in the NACA altitude wind tunnel. Oscillograph traces of controlled accelerations (throttle bursts),oontrolled decelerations (throttle chops), and controlled altitude starts are presented.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE50G12
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  • 56
    Publication Date: 2019-07-11
    Description: A modified J33-A-27 compressor was operated over a range of equivalent impeller speeds from 6100 to 13,250 rpm in order to obtain the over-all compressor performance. At the equivalent design speed of 11,800 rpm, the maximum efficiency of 0.764 and peak pressure ratio of 4.56 occurred at an equivalent weight flow of 104.07 pounds per second. At the highest equivalent speed (13,250 rpm) a maximum efficiency of 0.711, a maximum equivalent weight flow of 123.00 pounds per second, and a peak pressure ratio of 5.76 were obtained.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE50D25
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  • 57
    Publication Date: 2019-07-12
    Description: An investigation is being conducted to determine the performance of the 12-stage axial-flow compressor of the XT-46 turbine-propeller engine. This compressor was designed to produce a pressure ratio of 9 at an adiabatic efficiency of 0.86. The design pressure ratios per stage were considerably greater than any employed in current aircraft gas-turbine engines using this type of compressor. The compressor performance was evaluated at two stations. The station near the entrance section of the combustors indicated a peak pressure ratio of 6.3 at an adiabatic efficiency of 0.63 for a corrected weight flow of 23.1 pounds per second. The other, located one blade-chord downstream of the last stator row, indicated a peak pressure ratio of 6.97 at an adiabatic efficiency of 0.81 for a corrected weight flow of 30.4 pounds per second. The difference in performance obtained at the two stations is attributed to shock waves in the vicinity of the last stator row. These shock waves and the accompanying flow choking, together with interstage circulatory flows, shift the compressor operating curves into the region where surge would normally occur. The inability of the compressor to meet design pressure ratio is probably due to boundary-layer buildup in the last stages, which cause axial velocities greater than design values that, in turn, adversely affect the angles of attack and turning angles in these blade rows.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE50E22
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  • 58
    Publication Date: 2019-07-11
    Description: The compressor from the XT-46 turbine-propeller engine was revised by removing the last two rows of stator blades and by eliminating the interstage leakage paths described in a previous report. With the revised compressor, the flow choking point shifted upstream into the last rotor-blade row but the maximum weight flow was not increased over that of the original compressor. The flow range of the revised compressor was reduced to about two-thirds that obtained with the original compressor. The later stages of the compressor did not produce the design static-pressure increase probably because of excessive boundary-layer build-up in this region. Measurements obtained in the ninth-stage stator showed that the performance up to this station was promising but that the last three stages of the compressor were limiting the useful operating range of the preceding stages. Some modifications in flow-passage geometry and blade settings are believed to be necessary, however, before any major improvements in over-all compressor performance can be obtained.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE50J10
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  • 59
    Publication Date: 2019-07-11
    Description: An investigation was conducted to determine the effects of water injection on the over-all performance of a modified J33-A-27 turbojet-engine compressor at the design equivalent speed of 11,800 rpm. The water-air ratio by weight was 0.05. With water injection the peak pressure ratio increased 9.0 per- cent, the maximum efficiency decreased 15 percent (actual numerical difference 0.12), and. the maximum total weight flow increased 9.3 percent.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE50F14
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  • 60
    Publication Date: 2019-07-11
    Description: The power plant from a Mark 25 aerial torpedo was investigated both as a two-stage turbine and as a single-stage modified turbine to determine the effect on overall performance of nozzle size and shape, first-stage rotor-blade configuration, and axial nozzle-rotor running clearance. Performance was evaluated in terms of brake, rotor, and blade efficiencies. All the performance data were obtained for inlet total to outlet static pressure ratios of 8, 15 (design), and 20 with inlet conditions maintained constant at 95 pounds per square inch gage and 1000 F for rotor speeds from approximately 6000 to 18,000 rpm.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-RM-SE50D12
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  • 61
    Publication Date: 2019-06-28
    Description: As part of a general investigation of propellers at high forward speeds, tests of two 2-blade propellers having the NACA 4-(3)(8)-03 and NACA 4-(3)(8)-45 blade designs have been made in the Langley 8-foot high-speed tunnel through a range of blade angle from 20 degrees to 60 degrees for forward Mach numbers from 0.165 to 0.725 to establish in detail the changes in propeller characteristics due to compressibility effects. These propellers differed primarily only in blade solidity, one propeller having 50 percent and more solidity than the other. Serious losses in propeller efficiency were found as the propeller tip Mach number exceeded 0.91, irrespective of forward speed or blade angle. The magnitude of the efficiency losses varied from 9 percent to 22 percent per 0.1 increase in tip Mach number above the critical value. The range of advance ratio for peak efficiency decreased markedly with increase of forward speed. The general form of the changes in thrust and power coefficients was found to be similar to the changes in airfoil lift coefficient with changes in Mach number. Efficiency losses due to compressibility effects decreased with increase of blade width. The results indicated that the high level of propeller efficiency obtained at low speeds could be maintained to forward sea-level speeds exceeding 500 miles per hour.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-TR-999
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  • 62
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-28
    Description: An investigation has been made to explore the possibilities of axial-flow compressors operating with supersonic velocities into the blade rows. Preliminary calculations showed that very high pressure ratios across a stage, together with somewhat increased mass flows, were apparently possible with compressors which decelerated air through the speed of sound in their blading. The first phase of the investigation was the development of efficient supersonic diffusers to decelerate air through the speed of sound. The present report is largely a general discussion of some of the essential aerodynamics of single-stage supersonic axial-flow compressors. As an approach to the study of supersonic compressors, three possible velocity diagrams are discussed briefly. Because of the encouraging results of this study, an experimental single-stage supersonic compressor has been constructed and tested in Freon-12. In this compressor, air decelerates through the speed of sound in the rotor blading and enters the stators at subsonic speeds. A pressure ratio of about 1.8 at an efficiency of about 80 percent has been obtained.
    Keywords: Aircraft Propulsion and Power
    Type: NACA-TR-974 , NACA-ACR-L6D02 , NACA-AR-36
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  • 63
    Publication Date: 2019-08-16
    Description: Contents: Preliminary notes on the efficiency of propulsion systems; Part I: Propulsion systems with direct axial reaction rockets and rockets with thrust augmentation; Part II: Helicoidal reaction propulsion systems; Appendix I: Steady flow of viscous gases; Appendix II: On the theory of viscous fluids in nozzles; and Appendix III: On the thrusts augmenters, and particularly of gas augmenters
    Keywords: Aircraft Propulsion and Power
    Type: NACA-TM-1259
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