Chemical Engineering / Kimya Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/14
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Article Solunabilir Tozun Su Spreyleri Kullanılarak Bastırılmasında Son Gelişmeler(2000) Polat, Hürriyet; Polat, Mehmet; Gürgen, SabitTürkiye'de görülen meslek hastalıklarının çoğunu tozun solunmasından kaynaklanan pnömokonyoz oluşturmaktadır. Bu yazının amacı, yeraltı ocaklarında işçi sağlığı açısından sakıncalı olan havada asılı tozların, su spreyleri kullanılarak bastırılması konusunda gelinen aşamayı sunmaktır. Bu amaçla, havada asılı toz ve su damlalarıyla yapılan detaylı çalışmalar ışığında, sprey suyuna katılan yüzey aktif maddelerin istenen verim artışını sağlayamama nedenleri ele alınmakta ve su spreylerinin Türkiye'deki maden ocaklarında kullanım olanakları tartışılmaktadır.Conference Object Effect of Some Physical, and Chemical Variables on Flocculation and Sediment Behaviour(A.A. Balkema Publishers, 2000) Polat, Hürriyet; Polat, Mehmet; İpekoğlu, ÜnerEffect of some chemical and physical variables on the settling rate, final sediment height, sediment viscosity and supernatant turbidity of a clay sample was studied using various polyacrylamide type flocculants. Increasing flocculant concentration significantly increased both the settling rate and sediment viscosity. More importantly, changes in the final sediment, height, hence the packing density, was minimal for all the conditions tested once the sediment was allowed to consolidate. Also, the mode of addition of the polymer, at once or continuous, did not seem to affect any of the parameters measured. Conditioning time seemed to alter the settling rate at low polymer concentrations, but had no effect at high polymer concentrations. However, increasing the conditioning time caused a decrease in the sediment viscosity. Different types of the polyacrylimides generated different settling rates at a given concentration, but the final sediment height was nearly independent of polymer type.Conference Object Solution of the Non-Linear Poisson Boltzmann Theory for the General Case of Dissimilar Double Layers(2006) Polat, MehmetCalculation of the surface potentials, surface charges or electrostatic pressure for interacting colloidal particles is exceedingly important in mineral processing, environmental engineering, ceramic sciences, etc. Such calculations require solving the non-linear Poisson-Boltzmann theory at each plate separation. Though approximate analytical solutions of this theory are available for simplified cases, a general, but compact analytical solution is yet to be developed. A solution with no restrictions on surface potentials or charges is developed in this paper. The expressions developed are straightforward and require as input only the surface potentials at infinite separations.Book Part Citation - Scopus: 6Recent Advances in Chitosan-Based Systems for Delivery of Anticancer Drugs(Springer, 2020) Polat, Mehmet; Polat, HürriyetProblems in transporting drug molecules to tumor sites in required dose or constitution lead to low efficacy and significant side effects. Shielding the drug molecules in micelles, liposomes, or nanoparticles is a major line of investigation to improve chemotherapeutic treatment. Though compatibility for proper envelopment of the drug and timely release at the tumor site are required of such a carrier, protecting its own physicochemical and morphological integrity during transport is another precondition. Because of its superior polymerization capability, biocompatibility, pH dependence, and charging characteristics, chitosan has been in the forefront of potential drug carriers. Numerous synthesis routes for chitosan-based nanocarriers have been suggested to the extent that a search of the literature published since 2000 with the keywords “novel + nano + chitosan” in the title results in 527 articles, indicating the bewildering quality and quantity of the new information. This review was carried out not only to peruse this large amount of work on chitosan-based anticancer drug delivery but also to extract manageable patterns from numerous synthesis routes. The main conclusion is that the synthesis methods suggested in literature can be combined into two main routes, and the degree of hydrophobicity of the drug determines which route should be followed. © Springer Nature Singapore Pte Ltd. 2019.Book International Porous and Powder Materials Symposium and Exhibition Ppm 2015, 15-18 September 2015, Izmir-Turkey(Organizing Committee of the International Porous and Powder Materials Symposium and Exhibition, 2015) Polat, Mehmet; Tanoğlu, Metin; Kılıç Özdemir, Sevgi; Polat, Mehmet; Tanoğlu, MetinWe welcome you to the International Porous and Powder Materials Symposium and Exhibition, PPM 2015. The foreword of the proceedings and the abstracts books of the previous symposium, PPM 2013 which was the first of its series, started with the following sentence: ‘Idea of organizing a symposium on porous and powder materials owes its germination to the curiosity about the “other side of the fence”.’ It was a very fitting and almost a prophetic statement because 700 participants from 50 countries hosted by PPM 2013 belonged to an incredibly wide spectrum of science and technology, who one way or another dealt with porous and powder materials. It was both a fascinating and engaging sight to have people from the cement industry sitting in the sessions related to Biological and Medical Aspects since they realized that a characterization technique used in this field may actually answer some questions in theirs. Do we not deal with the same basic questions when we truly try to understand a material no matter where it originates from or how it is being put into application?Book International Porous and Powder Materials Symposium and Exhibition Ppm 2013, 3-6 September 2013, Çeşme Izmir-Turkey(Organizing Committee of the International Porous and Powder Materials Symposium and Exhibition, 2013) Özdemir, Sevgi Kılıç; Polat, Mehmet; Tanoğlu, Metin; Kılıç Özdemir, Sevgi; Polat, Mehmet; Tanoğlu, MetinWe welcome you to the first of the International Porous and Powder Materials Symposium and Exhibition, PPM 2013. The idea of organizing a symposium on porous and powder materials owes its germination to the curiosity about the ‘other side of the fence’. We are all familiar of the mild surprise when we come accross with a research paper from a totaly unrelated field written in a completely different terminology but describing something pleasantly familiar. Just imagine the elation of a PhD student in ceramics who is trying to optimize the stability and plasticity of the green body reading about the double layer around a protein, of an environmental engineer who is attempting to flocculate a nasty sludge coming accross with the concept of aggregation of micellar structures or of a researcher in chemical engineering who is looking for the perfect catalyst seeing the SEM pictures of porous nanoparticles developed for drug delivery. The list could be extended with much better examples by the readers of this book. But the best set of words to describe these feelings is an awareness of wholeness and solidarity.Conference Object Citation - Scopus: 3Characterization of Polysulfone Based Hemodialysis Membranes by Afm(Elsevier Ltd., 2012) Uz, Metin; Yaşar Mahlıçlı, Filiz; Polat, Mehmet; Alsoy Altınkaya, SacideMost of the hemodialysis membrane materials are hydrophobic in nature and allow protein adsorption on the surface easily due to hydrophobic interaction between membrane surface and protein molecules when in contact with blood. Adsorbed proteins can affect platelet and leukocyte adhesion, and modulate the response of plasmatic reactions followed by the activation of different defense systems in blood (Sun et al. 2003).Article Citation - WoS: 98Citation - Scopus: 108Capacity and Mechanism of Phenol Adsorption on Lignite(Elsevier Ltd., 2006) Polat, Hürriyet; Molva, Murat; Polat, MehmetA raw lignitic coal from Soma, Turkey was investigated to determine its potential as an adsorbent for phenol removal from wastewaters. Kinetic batch tests demonstrated that phenol could be completely removed from solution given sufficient solids loading and reaction time. The adsorption capacity of 10 mg/g obtained with the lignite is low compared to those achievable with activated carbons (around 300 mg/g). However, when normalized for the surface area, the adsorption capacity was much larger for the lignite (1.3 mg/m2) than that generally observed with activated carbons (0.05-0.3 mg/m2). Hydrogen-bonding of the phenolic -OH with the oxygen sites on the lignite surface is the most likely mechanism for adsorption. Though water molecules also have affinity for the same oxygen sites, lateral benzene ring interactions make phenol adsorption energetically more favorable. Since phenol molecules adsorbed in this fashion would project their benzene rings into solution, formation of a second layer through the action of the dispersive π-π interactions between the benzene rings is very likely. Residual water quality with respect to major elements and heavy metals was within acceptable limits defined by the ASTM standards. Dissolution of organic matter from the lignite was also observed to be negligible.Article Citation - WoS: 198Citation - Scopus: 210Physical and Chemical Interactions in Coal Flotation(Elsevier Ltd., 2003) Polat, Mehmet; Polat, Hürriyet; Chander, SubhashCoal flotation is a complex process involving several phases (particles, oil droplets and air bubbles). These phases simultaneously interact with each other and with other species such as the molecules of a promoting reagent and dissolved ions in water. The physical and chemical interactions determine the outcome of the flotation process. Physical and chemical interactions between fine coal particles could lead to aggregation, especially for high rank coals. Non-selective particle aggregation could be said to be the main reason for the selectivity problems in coal flotation. It should be addressed by physical (conditioning) or chemical (promoters) pretreatment before or during flotation. Although the interactions between the oil droplets and coal particles are actually favored, stabilization of the oil droplets by small amounts of fine hydrophobic particles may lead to a decrease in selectivity and an increase in oil consumption. These problems could be remedied by use of promoters that modify the coal surface for suitable particle-particle, droplet-particle and particle-bubble contact while emulsifying the oil droplets. The role of promoters may be different for different types of coals, however. They could be employed as modifiers to increase the hydrophobicity of low rank coals whereas their main role might be emulsification and aggregation control for high rank coals. In this paper, a detailed description of the various phases in coal flotation, their physical and chemical interactions with each other in the flotation pulp, the major parameters that affect these interactions and how these interactions, in turn, influence the flotation process are discussed.