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Search Results: 1 - 10 of 361602 matches for " G.L.;FREIRE "
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Phenol removal through combined biological and enzymatic treatments
Bevilaqua, J.V.;Cammarota, M.C.;Freire, D.M.G.;Sant?Anna Jr., G.L.;
Brazilian Journal of Chemical Engineering , 2002, DOI: 10.1590/S0104-66322002000200010
Abstract: this work studies the use of biological and combined biological/enzymatic treatments in phenol degradation. the systems studied were conventional batch aerobic biological followed or preceded by enzymatic treatment. tyrosinase extracted from the mushroom agaricus bispora was employed. biological treatment efficiently degraded effluents containing up to 420 mg.l-1 of phenol, removing 97% of the cod and 99% of the phenol in 48-hour batches. alterations in phenol concentration intake reduced treatment efficiency significantly. enzymatic polishing of biotreated effluent removed up to 75% of the remaining phenol in a four-hour reaction with 46 u.ml-1 of tyrosinase and 50 mg.l-1 of chitosan (used as coagulant). enzymatic pretreatment with 20 u.ml-1 of tyrosinase reduced the phenol concentration by 25 % after 2 hours of reaction, although initial cod increased up to 58%. the subsequent biological treatment of that enzymatic pretreated effluent reduced cod to 151 mgo2.l-1 and phenol concentration to 1 mg.l-1 in 24-hours batches.
Phenol removal through combined biological and enzymatic treatments
Bevilaqua J.V.,Cammarota M.C.,Freire D.M.G.,Sant?Anna Jr. G.L.
Brazilian Journal of Chemical Engineering , 2002,
Abstract: This work studies the use of biological and combined biological/enzymatic treatments in phenol degradation. The systems studied were conventional batch aerobic biological followed or preceded by enzymatic treatment. Tyrosinase extracted from the mushroom Agaricus bispora was employed. Biological treatment efficiently degraded effluents containing up to 420 mg.L-1 of phenol, removing 97% of the COD and 99% of the phenol in 48-hour batches. Alterations in phenol concentration intake reduced treatment efficiency significantly. Enzymatic polishing of biotreated effluent removed up to 75% of the remaining phenol in a four-hour reaction with 46 U.mL-1 of tyrosinase and 50 mg.L-1 of chitosan (used as coagulant). Enzymatic pretreatment with 20 U.mL-1 of tyrosinase reduced the phenol concentration by 25 % after 2 hours of reaction, although initial COD increased up to 58%. The subsequent biological treatment of that enzymatic pretreated effluent reduced COD to 151 mgO2.L-1 and phenol concentration to 1 mg.L-1 in 24-hours batches.
The Effect of Partial Replacement of Cement with Crushed Waste Glass in Laterized Concrete Production
G.L. Oyekan
Research Journal of Applied Sciences , 2012,
Abstract: Technologists, engineers and scientists are continuously on the lookout for materials which can be used as substitutes for conventional materials or which possess such properties that would enable them to be used for new designs and innovations. The waste materials that can be used in making concrete are many and include both organic and inorganic wastes. These materials may be used as a binder material, as partial replacement of conventional Portland cements or directly as aggregates in their natural or processed states. This study examines the effect of crushed waste glass (CWG) when used as partial substitute for cement in laterized concrete. One mix proportion (1:2:4) of cement + CWG, sand, latente and granite coarse aggregate was used with a constant water/cement ratio of 0.65. The effect of crushed waste glass on 2 properties of laterized concrete, namely, compressive strength and workability was investigated. The results showed that the CWG did not enhance the compressive strength of laterized concrete. The compressive strength of the laterized concrete actually decreased as the percentage CWG content increased. Laterized concrete (at 25, 50 and 75% laterite content) showed an initial increase in workability with increases in percentage CWG content in the cement matrix with the maximum slump being obtained at 25% CWG content. Further increases in CWG content resulted in decreased workability. The results also showed that laterized concrete containing 50% laterite and 15% cement replacement with CWG can be used for low/medium cost housing development.
Effect of Admixtures on the Compressive Strength of Sandcrete Blocks
G.l. Oyekan
Journal of Engineering and Applied Sciences , 2012,
Abstract: Sandcrete blocks are extensively used for cladding, load-bearing purposes and for demarcating properties in Nigeria and other nations around the world. The need to produce high quality sandcrete blocks of low cost in an impoverished economy like we have in Nigeria has necessitated research into the use of locally available raw materials in sandcrete block production. This study reports on the investigation carried out to determine the effect of admixtures (sawdust and sugar) on the compressive strength of sandcrete blocks. Results showed that sawdust did not significantly enhance the compressive strength of sandcrete blocks. The results on the use of sugar showed that that sugar had a significant effect on the compressive strength of the blocks increasing it by 17% at 28 days. Both admixtures slowed down the setting and early stiffening of the mortar mix.
Pre- and postnatal growth phenomena of Burchell's Zebra Equus Burchelli Antiquorum
G.L. Smuts
Koedoe : African Protected Area Conservation and Science , 1975, DOI: 10.4102/koedoe.v18i1.915
Abstract: Between 1969 and 1972 growth data were collected from 175 zebra Equus burchelli antiquorum and 138 zebra embryos and foetuses from the Central District of the Kruger National Park, Republic of South Africa. Statistical analysis of data indicated no significant difference between body mass of adult stallions (range == 267,3 to 373,3 kg; mean = 318,5 kg; n = 57) and adult non-pregnant mares (range = 272,6 to 386,9 kg; mean = 321,6 kg; n = 51) (t = 0,587). The heaviest zebra had a body mass of 429,4 kilogram. This was a pregnant mare carrying a 35,2 kg foetus. Von Bertalanffy growth curves indicated that shoulder heights in young zebra may reach the adult range by one year of age, the adult body mass range is, however, only attained after three years of age. These curves also showed that age classification of free roaming zebra is only reliable up to the age of about two years, after which individual variation is too great. Stallions were significantly taller at the shoulder than mares (mean = 1,8 cm) (t = 2,032) and neck thickness was the only body dimension showing visible sexual dimorphism in adults. Here the stallion had a neck girth on average 8,1 cm greater than the mare. Regression equations for estimating body mass from body dimensions were calculated by using a standard logarithmic transformation and fitting a linear regression by the method of least squares and also by undertaking standard straight line linear regression analyses. Exponential curves obtained by the first method indicated that growth was not isometric (not linear) and that the ratios of any of the dimensions of length to body mass were con- stantly changing, i.e. growth is allometric. Marked allometric growth differences existed between the two sexes except in the case of the heart girth-body mass relationship. Comparison of growth data from E. b. antiquorum with that of E. b. boehmi from Tanzania (Sachs 1967), indicates that E. b. antiquorum is considerably larger. Body masses differ by an average of 70 kg and 102 kg for stallions and mares respectively. Average birth mass for zebra was 33,7 kg. The largest foetus had a body mass of 39,0 kilogram. Foetal growth curves are provided. The first signs of body stripes occur at between 250 and 270 days of pregnancy (gestati
Xylazine Hydrochloride (Rompun) and the new retractable-barbed dart ("drop-out" dart) for the capture of some nervous and aggressive antelope species
G.L. Smuts
Koedoe : African Protected Area Conservation and Science , 1973, DOI: 10.4102/koedoe.v16i1.893
Abstract: he successful capture and restraint of gemsbok, eland and kudu using the potent sedative, Xylazine hydrochloride (Rompun, Bayer) and the new retractable-barbed dart ("drop-out" dart) is described. These species were rapidly immobilized and rendered 100 per cent tractable by Etorphine/Rompun or Fentanyl/Rompun drug combinations. The drop-out dart proved to be invaluable for the capture of timid species as flight distances were greatly reduced and the chances of capture myopathy (overstraining disease) subsequently obviated.
Home range sizes for burchell's zebra equus burchelli antiquorum from the Kruger National Park
G.L. Smuts
Koedoe : African Protected Area Conservation and Science , 1975, DOI: 10.4102/koedoe.v18i1.918
Abstract: Annual home range sizes were determined for 49 marked zebra family groups in the Kruger National Park. Sizes varied from 49 to 566 sq. km, the mean for the Park being 164 square kilometre. Mean home range sizes for different zebra sub-populations and biotic areas were found to differ considerably. Present herbivore densities have not influenced intra- and inter-specific tolerance levels to the extent that home range sizes have increased. Local habitat conditions, and particularly seasonal vegetational changes, were found to have the most profound influence on the shape and mean size of home ranges. The large home range sizes obtained in the Kruger Park, when compared to an area such as the Ngorongoro Crater, can be ascribed to a lower carrying capacity with respect to zebra, large portions of the habitat being sub-optimal, either seasonally or annually.
Ketamine Hydrochloride - a useful drug for the field immobilization of the Spotted Hyaena Crocuta Crocuta
G.L. Smuts
Koedoe : African Protected Area Conservation and Science , 1973, DOI: 10.4102/koedoe.v16i1.894
Abstract: The use of Ketamine hydrochloride (Vetalar, Parke-Davis) for the capture and restraint of five spotted hyaenas (Crocuta crocuta) is discussed. The wide margin of safety andrelatively short recovery period associated with Ketamine makeit a useful substitute for drugs such as Phencyclidine hydro-chloride (Sernylan) and Succinylcholine Chloride, routinely used for the capture of carnivores.
Making it new in 1884; Lie Kim Hok's Syair Siti Akbari
G.L. Koster
Bijdragen tot de Taal-, Land- en Volkenkunde , 1998,
Abstract:
Role of Biochemical Investigations in Assessment of the Newborn Kidney Function Damage after a Hypoxia
G.L. Shunkina
Sovremennye Tehnologii v Medicine , 2010,
Abstract: Aim of investigation is revealing of the kidney work disturbance peculiarities in newborns at the background of endured hypoxia.Materials and methods. 135 newborns, treating at a CICH №1 of N. Novgorod at the first week of life with endured hypoxia of a different degree of gravity, are examined. The biochemical investigations were conducted according to a certain scheme; a fermenturia degree was also studied.Results. The trustworthy data is received that the kidney functions are disturbed at hypoxia: a filtration rate is decreased, which is expressed by a creatinin level increase in a blood serum; the tubular and glomerular apparates of kidneys suffer, which is confirmed by the gamma-glutamyltransferase and cholinesterase activity increase in urine; the disturbances in a calcium and phosphoric metabolism take place.Conclusion. A complex of biochemical investigations for the kidney damage assessment is recommended for children endured a hypoxia.
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