Now showing items 1-20 of 1754

    • Reconceptualising sustainability assessment 

      Pope, Jenny; Bond, Alan; Morrison-Saunders, Angus; Hugé, Jean (Elsevier, 2017)
      Sustainability assessment as an ex ante tool for directing decision-making towards sustainability has emerged in a diverse range of forms across the world over the past decade or so. This broad practice of sustainability ...
    • Current status, hurdles and future prospects of biogas digestion technology in Africa 

      Roopnarain, Ashira; Adeleke, Rasheed (Elsevier, 2017)
      Anaerobic digestion of organic wastes results in the production of biogas and a nutrient-rich digestate. The biogas that is produced through this process consists of methane, carbon dioxide and minute amounts of other ...
    • Sequential rank CUSUM charts for angular data 

      Lombard, F.; Hawkins, Douglas M.; Potgieter, Cornelis J. (Elsevier, 2017)
      A cumulative sum (CUSUM) control chart has desirable properties for checking whether a distribution has changed from an in-control to an out-of-control setting. Distribution-free CUSUMs based on sequential ranks to detect ...
    • Structural assignment of commercial polyisobutylene succinic anhydride-based surfactants 

      Van der Merwe, Marina M.; Jordaan, Johannes H.L.; Otto, Daniel P.; Landman, Marilé; Van Rooyen, Petrus H. (Springer, 2017)
      Concentration of the surface active agents in industrial products is a common source of error. In order to compare the efficiency of a number of polyisobutylene succinic anhydride (PIBSA) based surfactants, their concentration ...
    • Polyol preparation by liquefaction of technical lignins in crude glycerol 

      Muller, Louis C.; Marx, Sanette; Vosloo, Hermanus C.M. (Scrivener Publishing, 2017)
      This work reports a study of polyol synthesis through liquefaction of technical lignins in crude glycerol by means of 1H and 31P NMR spectroscopy. The polyols are intended for preparation of polyurethane foam; thus, it is ...
    • Low-literate consumers' use of clothing labels amidst personal and product related challenges 

      Van Staden, Hanlie; Van der Merwe, Daleen; Van Aardt, Annette; Ellis, Susanna (Wiley, 2017)
      Low-literate consumers experience various challenges in the marketplace. This quantitative study focused on low-literate female consumers' use of clothing labels amidst personal and product-related challenges in the ...
    • Relativistic jets in active galactic nuclei and microquasars 

      Romero, Gustavo E.; Böttcher, M.; Markoff, S.; Tavecchio, F. (Springer, 2017)
      Collimated outflows (jets) appear to be a ubiquitous phenomenon associated with the accretion of material onto a compact object. Despite this ubiquity, many fundamental physics aspects of jets are still poorly understood ...
    • Graphs with sparsity order at most two: the complex case 

      Ter Horst, S.; Klem, E.M. (Taylor & Francis, 2017)
      The sparsity order of a (simple undirected) graph is the highest possible rank (over or ) of the extremal elements in the matrix cone that consists of positive semidefinite matrices with prescribed zeros on the positions ...
    • Particle scattering off of right-handed dispersive waves 

      Schreiner, C.; Spanier, F.; Kilian, P. (IOP Publishing, 2017)
      Resonant scattering of fast particles off low frequency plasma waves is a major process determining transport characteristics of energetic particles in the heliosphere and contributing to their acceleration. Usually, only ...
    • Class II 6.7 GHz methanol maser association with young massive cores revealed by ALMA 

      Chibueze, James O.; Csengeri, Timea; Tatematsu, Ken'ichi; Hasegawa, Tetsuo; Iguchi, Satoru (American Astronomical Society, 2017)
      We explored the implication of the association (or lack of it) of 6.7 GHz class II methanol (CH3OH) masers with massive dense cores (MDCs) detected (within a sample of ATLASGAL selected infrared quiet massive clumps) at ...
    • The re-acceleration of galactic electrons at the heliospheric termination shock 

      Prinsloo, P.L.; Potgieter, M.S.; Strauss, R.D. (American Astronomical Society, 2017)
      Observations by the Voyager spacecraft in the outer heliosphere presented several challenges for the paradigm of diffusive shock acceleration (DSA) at the solar wind termination shock (TS). In this study, the viability of ...
    • Phosphonic acid functionalized poly(pentafluorostyrene) as polyelectrolyte membrane for fuel cell application 

      Atanasov, Vladimir; Kerres, Jochen; Oleynikov, Andrey; Xia, Jiabing; Lyonnard, Sandrine (Elsevier, 2017)
      In this paper we introduce polyelectrolyte membranes based on phosphonated poly(pentafluorostyrene) (PPFS) and their performances in a fuel cell. The polyelectrolytes were obtained via partial phosphonation of PPFS varying ...
    • Copula-graphic estimation with left-truncated and right-censored data 

      De Uña-Alvarez, Jacobo; Veraverbeke, Noël (Taylor & Francis, 2017)
      In Survival Analysis and related fields of research right-censored and left-truncated data often appear. Usually, it is assumed that the right-censoring variable is independent of the lifetime of ultimate interest. However, ...
    • Exposure to high levels of fumarate and succinate leads to apoptotic cytotoxicity and altered global DNA methylation profiles in vitro 

      Wentzel, Johannes F.; Lewies, Angelique; Bronkhorst, Abel J.; Van Dyk, Etresia; Du Plessis, Lissinda H.; Pretorius, Piet J. (Elsevier, 2017)
      In the Krebs cycle, succinate is oxidized to fumarate by succinate dehydrogenase (SDH), followed by the conversion of fumarate to malate by fumarate hydratase (FH). In cells with defective SDH and FH, the Krebs cycle is ...
    • Synthesis and structural investigation of mono- and dimetallic N-heterocyclic carbene complexes of group VII transition metals 

      Fraser, Roan; Van Sittert, Cornelia G.C.E.; Van Rooyen, Petrus H.; Landman, Marilé (Elsevier, 2017)
      N-heterocyclic carbene complexes of group VII transition metals (Mn and Re) were synthesized and the electronic and structural aspects theoretically investigated. The synthesis yielded carbene complexes of type [Mx(CO)yL(NHC)] ...
    • The quadratic variation of continuous time stochastic processes in vector lattices 

      Grobler, Jacobus J.; Labuschagne, Coenraad C.A. (Elsevier, 2017)
      We define and study order continuity, topological continuity, γ-Hölder-continuity and Kolmogorov–Čentsov-continuity of continuous-time stochastic processes in vector lattices and show that every such kind of continuous ...
    • Very high energy outburst of Markarian 501 in May 2009 

      Aliu, E.; Böttcher, M.; Archambault, S.; Archer, A.; Arlen, T. (EDP Sciences, 2016)
      The very high energy (VHE; E> 100 GeV) blazar Markarian 501 was observed between April 17 and May 5 (MJD 54 938–54 956), 2009, as part of an extensive multi-wavelength campaign from radio to VHE. Strong VHE γ-ray activity ...
    • A canonical form for H-unitary matrices 

      Groenewald, G.J.; Janse van Rensburg, D.B.; Ran, A.C.M. (Ele-Math, 2016)
      In this paper matrices A are considered that have the property that A∗HA = H ,where H = H∗ is invertible. A canonical form is given for the pair of matrices (A,H) under transformations (A,H) → ( S−1AS,S∗HS), ...
    • New evidence for charge-sign-dependent modulation during the solar minimum of 2006 to 2009 

      Di Felice, V.; Vos, E.E.; Potgieter, M.S.; Munini, R. (IOP Publishing, 2017)
      The PAMELA space experiment, in orbit since 2006, has measured cosmic rays (CRs) through the most recent period of minimum solar activity with the magnetic field polarity as A < 0. During this entire time, galactic electrons ...
    • Measurements of biogenic volatile organic compounds at a grazed savannah grassland agricultural landscape in South Africa 

      Jaars, Kerneels; Van Zyl, Pieter G.; Beukes, Johan P.; Josipovic, Micky; Venter, Andrew D.; Knoetze, Leandra; Cilliers, Dirk P.; Siebert, Stefan J.; Laakso, Lauri (EGU, 2016)
      Biogenic volatile organic compounds (BVOCs) play an important role in the chemistry of the troposphere, especially in the formation of tropospheric ozone (O3) and secondary organic aerosols (SOA). Ecosystems produce and ...