ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Publication Date: 2020-09-26
    Description: Most pumping machineries have a problem of obtaining a higher efficiency over a wide range of operating conditions. To solve that problem, an optimization strategy has been designed to widen the high-efficiency range of the double-suction centrifugal pump at design (Qd) and nondesign flow conditions. An orthogonal experimental scheme is therefore designed with the impeller hub and shroud angles as the decision variables. Then, the “efficiency-house” theory is introduced to convert the multiple objectives into a single optimization target. A two-layer feedforward artificial neural network (ANN) and the Kriging model were combine based on a hybrid approximate model and solved with swarm intelligence for global best parameters that would maximize the pump efficiency. The pump performance is predicted using three-dimensional Reynolds-averaged Navier–Stokes equations which is validated by the experimental test. With ANN, Kriging, and a hybrid approximate model, an optimization strategy is built to widen the high-efficiency range of the double-suction centrifugal pump at overload conditions by 1.63%, 1.95%, and 4.94% for flow conditions 0.8Qd, 1.0Qd, and 1.2Qd, respectively. A higher fitting accuracy is achieved for the hybrid approximation model compared with the single approximation model. A complete optimization platform based on efficiency-house and the hybrid approximation model is built to optimize the model double-suction centrifugal pump, and the results are satisfactory.
    Print ISSN: 1076-2787
    Electronic ISSN: 1099-0526
    Topics: Computer Science , Mathematics
    Published by Hindawi
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Publication Date: 2020-09-15
    Description: The present study aimed to investigate the physiochemical activities of Senna occidentalis (Linn) roots and phytochemicals as insecticidal (ethyl acetate and methanol) and antidiabetic (ethanolic extract) activities. Physicochemical properties were carried out by using Association of Official Analytical Chemist methods; thin layer chromatography was carried out according to the Stahl method. Larvicidal activity and LD50 were studied against the third instar of Culex quinquefasciatus mosquito larvae to detect and extract toxicity. The ethanolic extracts of the roots were orally tested at the dose 200 mg/kg for the hypoglycemic effect on induced hyperglycemia in normal rats, assessed in the ethanol extract, and were compared with diabetic control and standards glibenclamide 10 mg/kg. Physiochemical parameters showed high rate in the nitrogen-free extract (69.6%), curd fiber (14.5%), crude proteins (8.15%), ether extract (3.75%), and both ash and moisture (2%), and high concentrations values were found in potassium (43 mg/l) followed by phosphorous (28.5 mg/l), calcium (15 mg/l), sodium (3.65 mg/l), and magnesium (0.145 mg/l). In this part, phytochemical compounds showed high amount of alkaloids, triterpene, flavonoids, tannins, sugars, and few amount of anthraquinone glycosides. Thin-layer chromatography (TLC) studies different colored phytochemical constituted with different Rf values. All the spots are colored under UV light, but some are localized colorless after spaying. The ethyl acetate (EtAc) extract showed eight spots, and the methanol (MeOH) extract showed thirteen spots. The larvicidal activity showed that the ethyl acetate extract was safe against mosquito larvae with an LD50 value 1412.54 (p
    Print ISSN: 2090-2247
    Electronic ISSN: 2090-2255
    Topics: Biology , Chemistry and Pharmacology
    Published by Hindawi
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Publication Date: 1982-02-01
    Description: SUMMARYDifferent seeding combinations and monocultures of sorghum forage, Abu Sabein, and legume forage, Lubia, were grown under irrigation on saline marginal lands for two seasons. Certain seeding combination treatinents, particularly (¾ Abu Sabein + ¼ Lubia), produced higher total D.M. than the higher yielding component, Abu Sabein, grown as a monoculture. This mixture treatment, together with some others, yielded more total crude protein than Abu Sabein alone. The seeding combination treatments influenced the pattern of D.M. distribution amongst different strata in the crop canopy. As the percentage of Lubia in the mixture increased, the D.M. of Abu Sabein tended to accumulate in greater proportions in the higher strata.
    Print ISSN: 0021-8596
    Electronic ISSN: 1469-5146
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    The @journal of modern African studies 5 (1967), S. 288-288 
    ISSN: 0022-278X
    Source: Cambridge Journals Digital Archives
    Topics: Ethnic Sciences , History , Political Science , Economics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    The @journal of modern African studies 28 (1990), S. 199-224 
    ISSN: 0022-278X
    Source: Cambridge Journals Digital Archives
    Topics: Ethnic Sciences , History , Political Science , Economics
    Notes: This article discusses the political situation in the Sudan in the aftermath of the 1985 popular uprising which reinstated parliamentary democracy, and focuses on the major challenges which confronted the civilian leaders before their downfall, notably the economic crisis, the issue of Sharia law, the agonising war in the South, and the corrupt and inefficient party system.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    The @journal of modern African studies 8 (1970), S. 339-362 
    ISSN: 0022-278X
    Source: Cambridge Journals Digital Archives
    Topics: Ethnic Sciences , History , Political Science , Economics
    Notes: The 55 countries and territories of Africa can be classified today from the monetary point of view into six major groups. Of these, four are monetary areas based on the currency of the former or actual metropolitan country: the French franc, the pound sterling, the Portuguese escudo, and the Spanish peseta. The sterling area includes the area of the South African rand; and finally there is a group of independent countries, some with very new central banks and others with a longer tradition of monetary independence.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    The @journal of modern African studies 4 (1966), S. 558-560 
    ISSN: 0022-278X
    Source: Cambridge Journals Digital Archives
    Topics: Ethnic Sciences , History , Political Science , Economics
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Cambridge : Cambridge University Press
    The @journal of modern African studies 4 (1966), S. 155-176 
    ISSN: 0022-278X
    Source: Cambridge Journals Digital Archives
    Topics: Ethnic Sciences , History , Political Science , Economics
    Notes: The difficulties experienced by some African countries in settling their external payments have become a matter of considerable concern, both to the countries themselves as well as to the regional and international institutions concerned with economic and financial development. More and more countries are plagued by these difficulties, while the difficulties themselves continue to multiply. Nevertheless, it appears that the nature, the size, and the implications of these payments problems are not always fully understood. This article seeks to analyse them, to emphasise the need for further study and to seek possible solutions.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2015-06-01
    Description: We study the surfaces corresponding to solutions of the localized induction equation in the pseudo-Galilean space . We classify such surfaces with null curvature and characterize some special curves on these surfaces in .
    Print ISSN: 1687-9120
    Electronic ISSN: 1687-9139
    Topics: Mathematics , Physics
    Published by Hindawi
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2013-04-10
    Description: The purpose of this study is to present an approximate solution that depends on collocation points and Bernstein polynomials for a class of Lane-Emden type equations with mixed conditions. The method is given with some priori error estimate. Even the exact solution is unknown, an upper bound based on the regularity of the exact solution will be obtained. By using the residual correction procedure, the absolute error can be estimated. Also, one can specify the optimal truncation limit which gives a better result in any norm. Finally, the effectiveness of the method is illustrated by some numerical experiments. Numerical results are consistent with the theoretical results.
    Print ISSN: 1024-123X
    Electronic ISSN: 1563-5147
    Topics: Mathematics , Technology
    Published by Hindawi
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...