Zeki Aktas - Academia.edu (original) (raw)
Papers by Zeki Aktas
Fuel processing technology, 1996
... M: TECHNOLOGY ELSEVIER Fuel Processing Technology 48 (1996) 6172 Supercritical toluene extrac... more ... M: TECHNOLOGY ELSEVIER Fuel Processing Technology 48 (1996) 6172 Supercritical toluene extraction of a reduced Turkish lignite Zeki Aktas * , Aral 0lcay ... The lignite (run of mine, ROM) was crushed to particles of less than 5 mm diameter, which were then milled in a ball ...
International braz j urol : official journal of the Brazilian Society of Urology
Despite the well-known findings related to malignity in DRE such as nodule and induration, asymme... more Despite the well-known findings related to malignity in DRE such as nodule and induration, asymmetry of prostatic lobes, seen relatively, were investigated in a few studies as a predictor of prostate cancer so that there is no universally expected conclusion about asymmetry. We aimed to compare cancer detection rate of normal, asymmetric or suspicious findings in DRE by using biopsy results. Data of 1495 patients underwent prostate biopsy between 2006-2014 were searched retrospectively. Biopsy indications were abnormal DRE and or elevated PSA level( >4ng/mL). DRE findings were recorded as Group 1: Benign DRE, Group 2: Asymmetry and Group 3: Nodule/induration. Age, prostatic volume , biopsy results and PSA levels were recorded. Mean age, prostate volume and PSA level were 66.72, 55.98 cc and 18.61ng/ mL respectively. Overall cancer detection rate was 38.66 % (575 of 1495). PSA levels were similar in group 1 and 2 but significantly higher in group 3. Prostatic volume was similar in...
International journal of mineral processing, 2002
Spherical oil agglomeration of bituminous coal fines was carried out using diesel oil as a bridgi... more Spherical oil agglomeration of bituminous coal fines was carried out using diesel oil as a bridging liquid. The effects of parameters, such as the dosage of bridging liquid, the solid content of slurry, the agitation time and rate, the pH and surface active agent on the agglomeration performance, were investigated. When the bridging oil loading increased from 5 to 30 wt.%, the values of grade and recovery increased gradually. The grade increased from 0.62 to 0.79 and the recovery increased from 0.91 to 0.98. Under the test conditions reported, agitation time and rate did not significantly affect the grade and recovery values. When the solid content in the slurry increased from 5 to 25 wt.%, the grade values decreased from 0.75 to 0.6 and the recovery increased from 0.95 to 0.99. Laser particle size analyses of the agglomerate and tailing fractions showed that the agglomerates and tailings contained coarser and finer particles than the particles of the corresponding feed. However, the amounts of particles under 0.8 Am in the agglomerate fractions were higher than that of the tailing fractions. Variation of the pH of the slurry changed the agglomeration performance. The grade values were 0.78 and 0.72 for the pHs of 3.1 and 11, respectively. The addition of surface active agent (Triton X-100) caused a decrease in the recovery. However, the Triton X-100 in the slurry did not significantly change the grade of the final product.
Journal of Environmental Chemical Engineering
Applied Surface Science
A biomass based activated carbon was prepared by chemical activation using ZnCl 2 as an activatio... more A biomass based activated carbon was prepared by chemical activation using ZnCl 2 as an activation agent. Some of the activated carbon sample was subjected to a further single step heat treatment at 800°C under an inert atmosphere. Both carbon samples (untreated and heat treated) were tested as supercapacitor electrode materials. Further heat treatment significantly affected the surface properties of the carbon sample. Furthermore, a substantial enhancement in electrochemical performance was achieved in both aqueous and organic electrolytes despite its reduced specific surface area. The supercapacitor device based on the organic electrolyte exhibited higher rate capability than the aqueous one (KOH). The supercapacitor device assembled from the heat treated sample based on the organic electrolyte was scaled up from coin size to pouch size and the electrochemical response was maintained. Both coin and pouch supercapacitors showed good capacitance retention for over 10,000 cycles. This is comparable to the commercial high-rate activated carbon based supercapacitors.
Journal of Environmental Management
Journal of Industrial and Engineering Chemistry
Electrochimica Acta
Enhanced performance based on a hybrid cathode backing layer using a biomass derived activated ca... more Enhanced performance based on a hybrid cathode backing layer using a biomass derived activated carbon framework for methanol fuel cells. Electrochimica Acta.
Journal of Cleaner Production, 2017
The adsorption of reagent on the surface of porous material and the regeneration of porous materi... more The adsorption of reagent on the surface of porous material and the regeneration of porous material are significant processes that are widely used in chemical industries. The performance of a granular commercial activated carbon and two activated carbons synthesised from the factory waste tea and demineralised waste tea, were tested during a series of adsorption and regeneration cycles. Phenol and p-nitrophenol (PNP, 4nitrophenol) were used as the reagents to represent water pollutants. The activated carbon samples were regenerated by the application of a short period of microwave energy (30 s). The influence of the microwave regeneration process on the surface area and pore volumes were investigated with laboratory characterisation techniques. Several cycles of adsorption and regeneration processes were conducted to determine the variation in the adsorption capacity and the characteristics of each porous material. The adsorption and regeneration processes were interpreted in terms of the amount of adsorbed reagent and surface characteristic of the porous material. The materials were found to be good adsorbents for phenol and PNP and the regeneration process worked effectively; broadly maintaining the adsorption capacity over multiple adsorption-regeneration cycles.
Computers Chemical Engineering, May 1, 2004
Froth flotation is an effective process for separating sulphur and fine minerals from coal. Such ... more Froth flotation is an effective process for separating sulphur and fine minerals from coal. Such pre-cleaning of coal is necessary in order to reduce the environmental and operational problems in power plants. The separation depends very much on particle surface properties, and the selectivity can be improved by addition of a reagent. Image analysis can be used to determine the amount of reagent, by using the relation between surface properties and froth bubble sizes. This work reports some improvements in the efficiency of the image analysis, and in determination of bubble diameter distribution towards developing froth-based flotation models. Ultimate benefit of the technique would allow a pre-determined reagent addition profile to be identified for controlling the separation process.
Radiat Phys Chem, 2005
The results of the treatment of activated carbons prepared from Turkish Elbistan lignite with γ-i... more The results of the treatment of activated carbons prepared from Turkish Elbistan lignite with γ-irradiation from a 60 Co source are presented and associated volatilization of surface material of the activated carbon as a means to obtain a physical modification of the material is ...
Applied Surface Science, 2015
Colloids and Surfaces A-physicochemical and Engineering Aspects, 2008
Hydroxyapatite (HA) nanoparticles were synthesized by precipitation method in the presence of sim... more Hydroxyapatite (HA) nanoparticles were synthesized by precipitation method in the presence of simulated body fluid (SBF) solution or calcium phosphor tris (CaPTris) solution which was used for the first time. The synthesized powders were characterized in terms of structure (Fourier transform infrared spectrograph, FTIR and X-ray diffraction, XRD), particle size and morphology (zeta sizer and scanning electron microscopy, SEM). HA
Applied Surface Science, 2014
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2014
ABSTRACT
Fuel processing technology, 1996
... M: TECHNOLOGY ELSEVIER Fuel Processing Technology 48 (1996) 6172 Supercritical toluene extrac... more ... M: TECHNOLOGY ELSEVIER Fuel Processing Technology 48 (1996) 6172 Supercritical toluene extraction of a reduced Turkish lignite Zeki Aktas * , Aral 0lcay ... The lignite (run of mine, ROM) was crushed to particles of less than 5 mm diameter, which were then milled in a ball ...
International braz j urol : official journal of the Brazilian Society of Urology
Despite the well-known findings related to malignity in DRE such as nodule and induration, asymme... more Despite the well-known findings related to malignity in DRE such as nodule and induration, asymmetry of prostatic lobes, seen relatively, were investigated in a few studies as a predictor of prostate cancer so that there is no universally expected conclusion about asymmetry. We aimed to compare cancer detection rate of normal, asymmetric or suspicious findings in DRE by using biopsy results. Data of 1495 patients underwent prostate biopsy between 2006-2014 were searched retrospectively. Biopsy indications were abnormal DRE and or elevated PSA level( >4ng/mL). DRE findings were recorded as Group 1: Benign DRE, Group 2: Asymmetry and Group 3: Nodule/induration. Age, prostatic volume , biopsy results and PSA levels were recorded. Mean age, prostate volume and PSA level were 66.72, 55.98 cc and 18.61ng/ mL respectively. Overall cancer detection rate was 38.66 % (575 of 1495). PSA levels were similar in group 1 and 2 but significantly higher in group 3. Prostatic volume was similar in...
International journal of mineral processing, 2002
Spherical oil agglomeration of bituminous coal fines was carried out using diesel oil as a bridgi... more Spherical oil agglomeration of bituminous coal fines was carried out using diesel oil as a bridging liquid. The effects of parameters, such as the dosage of bridging liquid, the solid content of slurry, the agitation time and rate, the pH and surface active agent on the agglomeration performance, were investigated. When the bridging oil loading increased from 5 to 30 wt.%, the values of grade and recovery increased gradually. The grade increased from 0.62 to 0.79 and the recovery increased from 0.91 to 0.98. Under the test conditions reported, agitation time and rate did not significantly affect the grade and recovery values. When the solid content in the slurry increased from 5 to 25 wt.%, the grade values decreased from 0.75 to 0.6 and the recovery increased from 0.95 to 0.99. Laser particle size analyses of the agglomerate and tailing fractions showed that the agglomerates and tailings contained coarser and finer particles than the particles of the corresponding feed. However, the amounts of particles under 0.8 Am in the agglomerate fractions were higher than that of the tailing fractions. Variation of the pH of the slurry changed the agglomeration performance. The grade values were 0.78 and 0.72 for the pHs of 3.1 and 11, respectively. The addition of surface active agent (Triton X-100) caused a decrease in the recovery. However, the Triton X-100 in the slurry did not significantly change the grade of the final product.
Journal of Environmental Chemical Engineering
Applied Surface Science
A biomass based activated carbon was prepared by chemical activation using ZnCl 2 as an activatio... more A biomass based activated carbon was prepared by chemical activation using ZnCl 2 as an activation agent. Some of the activated carbon sample was subjected to a further single step heat treatment at 800°C under an inert atmosphere. Both carbon samples (untreated and heat treated) were tested as supercapacitor electrode materials. Further heat treatment significantly affected the surface properties of the carbon sample. Furthermore, a substantial enhancement in electrochemical performance was achieved in both aqueous and organic electrolytes despite its reduced specific surface area. The supercapacitor device based on the organic electrolyte exhibited higher rate capability than the aqueous one (KOH). The supercapacitor device assembled from the heat treated sample based on the organic electrolyte was scaled up from coin size to pouch size and the electrochemical response was maintained. Both coin and pouch supercapacitors showed good capacitance retention for over 10,000 cycles. This is comparable to the commercial high-rate activated carbon based supercapacitors.
Journal of Environmental Management
Journal of Industrial and Engineering Chemistry
Electrochimica Acta
Enhanced performance based on a hybrid cathode backing layer using a biomass derived activated ca... more Enhanced performance based on a hybrid cathode backing layer using a biomass derived activated carbon framework for methanol fuel cells. Electrochimica Acta.
Journal of Cleaner Production, 2017
The adsorption of reagent on the surface of porous material and the regeneration of porous materi... more The adsorption of reagent on the surface of porous material and the regeneration of porous material are significant processes that are widely used in chemical industries. The performance of a granular commercial activated carbon and two activated carbons synthesised from the factory waste tea and demineralised waste tea, were tested during a series of adsorption and regeneration cycles. Phenol and p-nitrophenol (PNP, 4nitrophenol) were used as the reagents to represent water pollutants. The activated carbon samples were regenerated by the application of a short period of microwave energy (30 s). The influence of the microwave regeneration process on the surface area and pore volumes were investigated with laboratory characterisation techniques. Several cycles of adsorption and regeneration processes were conducted to determine the variation in the adsorption capacity and the characteristics of each porous material. The adsorption and regeneration processes were interpreted in terms of the amount of adsorbed reagent and surface characteristic of the porous material. The materials were found to be good adsorbents for phenol and PNP and the regeneration process worked effectively; broadly maintaining the adsorption capacity over multiple adsorption-regeneration cycles.
Computers Chemical Engineering, May 1, 2004
Froth flotation is an effective process for separating sulphur and fine minerals from coal. Such ... more Froth flotation is an effective process for separating sulphur and fine minerals from coal. Such pre-cleaning of coal is necessary in order to reduce the environmental and operational problems in power plants. The separation depends very much on particle surface properties, and the selectivity can be improved by addition of a reagent. Image analysis can be used to determine the amount of reagent, by using the relation between surface properties and froth bubble sizes. This work reports some improvements in the efficiency of the image analysis, and in determination of bubble diameter distribution towards developing froth-based flotation models. Ultimate benefit of the technique would allow a pre-determined reagent addition profile to be identified for controlling the separation process.
Radiat Phys Chem, 2005
The results of the treatment of activated carbons prepared from Turkish Elbistan lignite with γ-i... more The results of the treatment of activated carbons prepared from Turkish Elbistan lignite with γ-irradiation from a 60 Co source are presented and associated volatilization of surface material of the activated carbon as a means to obtain a physical modification of the material is ...
Applied Surface Science, 2015
Colloids and Surfaces A-physicochemical and Engineering Aspects, 2008
Hydroxyapatite (HA) nanoparticles were synthesized by precipitation method in the presence of sim... more Hydroxyapatite (HA) nanoparticles were synthesized by precipitation method in the presence of simulated body fluid (SBF) solution or calcium phosphor tris (CaPTris) solution which was used for the first time. The synthesized powders were characterized in terms of structure (Fourier transform infrared spectrograph, FTIR and X-ray diffraction, XRD), particle size and morphology (zeta sizer and scanning electron microscopy, SEM). HA
Applied Surface Science, 2014
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2014
ABSTRACT