Yazar "Ozkan, A" seçeneğine göre listele
Listeleniyor 1 - 13 / 13
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Coagulation and flocculation characteristics of celestite with different inorganic salts and polymers(ELSEVIER SCIENCE SA, 2004) Ozkan, A; Yekeler, MCoagulation and flocculation characteristics of celestite were investigated using CaCl2, MgCl2 and AlCl3 and anionic (A-150), cationic (C-573) and non-ionic (N-100) flocculants, respectively. Isoelectric point of celestite sample studied was found to be located at a pH of 2.6 using hindered settling technique. It was determined that the magnesium ion was more effective on the celestite suspension than calcium and aluminum ions and its effect significantly varied depending on concentration and pH of the suspension. The coagulation power values for magnesium ion increased rapidly towards the 5 x 10(-5) M concentration and reached a maximum value (similar to90%) at a pH of 11. While calcium and magnesium ions were not effective below neutral pH, aluminum ion caused the stabilization of the celestite suspension below pH 8.5. A-150 and N-100 polymers strongly flocculated the celestite suspension than C-573 polymer. While the celestite suspension with A-150 polymer was flocculated well at neutral and alkaline pH range, N-100 polymer was not much affected by the pH changes of the suspension. For the flocculation experiments with A-150 polymer at pH 11 with pre-addition of particular concentrations of calcium and magnesium ions into the suspension, i.e. destabilization process prior to the flocculation, the flocculation of the celestite suspension was enhanced by the coagulation process. (C) 2003 Elsevier B.V. All rights reserved.Öğe Critical solution surface tension for oil agglomeration(ELSEVIER SCIENCE BV, 2005) Ozkan, A; Aydogan, S; Yekeler, MThis paper presents the effect of surface tension of solution used as medium for the oil agglomeration of minerals. Naturally occurring hydrophobic and hydrophilic minerals are used in this study. It was determined that the oil agglomeration recoveries of these minerals decreased with decreasing solution surface tension and the oil agglomeration process of the mineral did not occur below a particular value of solution surface tension. The solution surface tension value at which oil agglomeration does not take place was defined as 'the critical solution surface tension for oil agglomeration, gamma (c-a)'. These critical solution surface tension values obtained for those hydrophobic minerals were close to their critical surface tension of wetting (gamma(c)) values. On the other hand, the gamma(c-a) values obtained for the hydrophilic minerals treated with surfactants were slightly higher than their gamma(c) values. For a successful oil agglomeration of a mineral, the solution surface tension value must be higher than the critical surface tension of oil agglomeration (gamma(c-a)). (c) 2004 Elsevier B.V. All rights reserved.Öğe Delaying the reverse sural flap provides predictable results for complicated wounds in diabetic foot(LIPPINCOTT WILLIAMS & WILKINS, 2005) Tosun, Z; Ozkan, A; Karacor, Z; Savaci, NDefective wounds in diabetic foot are difficult to manage. Several studies reported the use of reverse sural flap in a small number of patients with varying success. We presented our experience with the reverse sural island flap (RSIF) in a series of 37 patients associated with diabetic foot using the delay procedure. The ages of the patients ranged between 36 and 73 years. We did not perform angiographic evaluation to determine the existence of vascular connections between the branches of the peroneal and posterior tibial artery; however, Doppler ultrasound evaluation was done to determine the patency of anterior and posterior tibial arteries, as well as lesser saphenous vein before the operation. The flaps were transferred using a 3-step delay procedure. While all the first and second steps of the operations were done under local anesthesia, the third steps were performed using general anesthesia in 12 and spinal anesthesia in 25 patients. All flaps survived except 4 showing partial necrosis due to venous insufficiency. Delaying the RSIF is a reliable procedure for diabetic foot skin defects.Öğe Destabilization characteristics of talc in distilled and fresh waters(NATL INST SCIENCE COMMUNICATION, 2004) Ozkan, AThe destabilization characteristics of talc were investigated in distilled and fresh water containing Ca2+, Ma(2+), Na+ and K+ ions. The stability of the talc suspension remained almost constant in distilled water at all pH values, while it sharply decreased with these cations (i.e. in fresh water) at pH values above 10.5. In addition, the effects of A-95 (anionic), C-521 (cationic) and N-100 (non-ionic) flocculants on the destabilization of the suspension were also investigated in distilled and fresh waters. In fresh water, anionic and non-ionic flocculants were very effective on the talc suspensions at pH 7.2 and at pH values greater than 10.5. The stability of talc suspension was decreased by flocculation and also coagulation effect at pH levels greater than 10.5. The cationic flocculant caused weak destabilization of the suspension with distilled water in acidic conditions. However, this polymer was ineffective on the talc suspensions in fresh water at almost all pH levels.Öğe Determination of the critical surface tension of wetting of minerals treated with surfactants by shear flocculation approach(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2004) Ozkan, AThis paper contributes the shear flocculation method as a new approach to determine the critical surface tension of wetting of minerals treated with surfactants. This newly developed approach is based on the decrease of the shear flocculation of the mineral suspension, with decreasing of the surface tension of the liquids used. The solution surface tension value at which shear flocculation does not occur can be defined as the critical surface tension of wetting (gamma(c)) of the mineral. By using the shear flocculation method, the critical surface tensions of wetting (gamma(c)) for calcite and barite minerals, treated with surfactants, were obtained as 30.9 and 35.0 mN/m, respectively. These values are in good agreement with data reported previously on the same minerals obtained by the contact angle measurement and flotation methods. The chemical agents used for the treatment of calcite and barite particles were sodium oleate and sodium dodecyl sulfate, respectively. (C) 2004 Elsevier Inc. All rights reserved.Öğe Drains in aesthetic surgery: Should they beradio-opaque or not?(SPRINGER, 2005) Tosun, Z; Sutcu, M; Ozkan, A; Savaci, N[Abstract not Available]Öğe Effects of isoflurane and sevoflurane on the survival of skin flaps in rats(TAYLOR & FRANCIS AS, 2005) Tosun, Z; Tuncer, S; Yosunkaya, A; Ozkan, A; Senturk, S; Savaci, NThe effects of inhalational anaesthetic agents on survival of flaps are not well known. We investigated the effect of isoflurane and sevoflurane anaesthesia on survival of flaps using a caudally-based McFarlane skin flap in 20 male Wistar rats. Sevoflurane 1 minimum alveolar concentration (MAC) and isoflurane (1 MAC) in oxygen mixture was given to the animals. A 4 x 10 cm caudally-based standard McFarlane flap was raised. There were no differences in any haemodynamic values or blood gases between the sevoflurane group and the isoflurane group. Skin flaps were assessed on the seventh day. The isoflurane group had a significantly smaller area of skin flap necrosis and an increased area of flap surviving than the sevoflurane group. We conclude that survival is significantly improved when isoflurane is used as the inhalational anaesthetic rather than sevoflurane.Öğe Is surgery always necessary in the treatment of aplasia cutis congenita?(LIPPINCOTT WILLIAMS & WILKINS, 2006) Tosun, Z; Ozkan, A; Savaci, N[Abstract not Available]Öğe Microsurgical training model for nerve repair(THIEME MEDICAL PUBL INC, 2005) Senturk, S; Tosun, Z; Ozkan, A[Abstract not Available]Öğe Palatal perforation as a result of neonatal sepsis(LIPPINCOTT WILLIAMS & WILKINS, 2005) Tosun, Z; Ozkan, A; Karacor, Z; Savaci, N[Abstract not Available]Öğe Shear flocculation of celestite with anionic surfactants and effects of some inorganic dispersants(ELSEVIER SCIENCE BV, 2006) Ozkan, A; Ucbeyiay, H; Aydogan, SShear flocculation characteristics of celestite (SrSO4) mineral have been investigated using sodium dodecyl sulfate (SDS) and Aero845 as anionic surfactants. The celestite suspension could be flocculated by SDS and Aero 845 in the broad pH range. However, these surfactants were slightly more effective on the celestite suspension at a pH of 7. The shear flocculation of celestite with SDS and Aero 845 increased rapidly with increasing surfactant concentration. However, it decreased at SDS concentrations higher than 45 mg/dm(3), and eventually stabilization of the suspension took place at concentration values above approximately 80 mg/dm3. From the experiments carried out to determine the effects of stirring speed and flocculation time on the shear flocculation of celestite suspension, it was found that a stirring speed of 500 rpm and a flocculation time of 3 min were required to achieve the maximum aggregation degree of celestite particles. The effects of sodium silicate, sodium phosphate and sodium polyphosphate used as inorganic dispersants on the shear flocculation of celestite were also studied. Sodium silicate strongly prevented the shear flocculation of celestite with SDS. However, the dispersive effect of sodium silicate was low in the presence of Aero 845. In the case of sodium polyphosphate, a dispersive effect on the celestite suspension was not observed for both surfactants. On the contrary, the shear flocculation power values increased slowly in the presence of sodium polyphosphate. In addition, the similar phenomenon also took place for sodium phosphate in the presence of SDS. (c) 2006 Elsevier B.V. All rights reserved.Öğe Shear flocculation of celestite with sodium oleate and tallow amine acetate: effects of cations(ACADEMIC PRESS INC ELSEVIER SCIENCE, 2004) Ozkan, A; Yekeler, MSodium oleate and tallow amine acetate (TAA) were used as surfactants for the shear flocculation of celestite. The shear-flocculation power values obtained with sodium oleate were higher than those obtained with TAA in terms of the concentrations used in the shear-flocculation experiments. In addition, sodium oleate and TAA were more effective on the celestite suspension in the pH ranges of 7-11 and 6-10, respectively. For the shear-flocculation experiments with sodium oleate at pH 11, with preaddition of calcium or magnesium ions at 5 x 10(-5) M and lower concentrations into the suspension, the shear-flocculation of the celestite suspension was promoted by the coagulation process due to the calcium and magnesium cations added. However, the shear-flocculation power values decreased due to the interaction between surfactant and cations at concentration values higher than 5 x 10-5 M for magnesium ions and 10(-3) M for calcium ion. Particularly, magnesium ions significantly reduced the shear-flocculation power values by slime coating of Mg(OH)(2) precipitates. (C) 2004 Elsevier Inc. All rights reserved.Öğe Two scrotal calcinosis cases with different causal mechanisms(LIPPINCOTT WILLIAMS & WILKINS, 2005) Tosun, Z; Karacor, Z; Ozkan, A; Toy, H; Savaci, N[Abstract not Available]
