Chemical Engineering

We introduce a novel method for predicting the secondary structure of proteins, PREDICT (PRofile Enumeration DICTionary), in which the nearest-neighbor method is applied to a pattern space. For a given protein sequence, PSI-BLAST is used to generate a profile that defines patterns for amino acid residues and their local sequence environments. By applying the PSI-BLAST to protein sequences with known secondary structures, we construct pattern databases. The secondary structure of a query residue of a protein with unknown structure can be determined by comparing the query pattern with those in the pattern databases and selecting the patterns close to the query pattern. We have tested the PREDICT on the CB513 set (a set of 513 non-homologous proteins) in three different ways. The first test was based on a pattern database derived from 7777 proteins in the Protein Data Bank (PDB), including those homologous to proteins in the CB513 set and gave an average Q3 score of 78.8 % per chain. In the second test, in order to carry out a more stringent benchmark test on the CB513 set, we removed from the 7777 proteins all proteins homologous to the CB513 set, leaving 4330 proteins. Pattern databases were constructed based on these proteins, and the average Q3 score was 74.6 %. In the third test, we selected one query protein among the CB513 set and built pattern databases by using the remaining 512 proteins. This procedure was repeated for each of the 513 proteins, and the average Q3 score was 73.1 %. Finally, we participated in the CASP5 (group ID: 531) where we employed the first-layer database based on the 7777 proteins and the second-layer database based on the CB513 set. The PREDICT gave quite promising results with an average Q3 (Sov) score of 78.1 (77.4) % on 55 CASP5 targets.

In this study, pistachio shell is taken as the biomass sample to investigate the effects of pyrolysis temperature on the product yields and composition when slow pyrolysis is applied in a fixed-bed reactor at atmospheric pressure to the temperatures of 300, 400, 500, 550, 700°C. The maximum liquid yield was attained at about 500-550°C with a yield of 20.5%. The liquid product obtained under this optimum temperature and solid products obtained at all temperatures were characterized. As well as proximate and elemental analysis for the products were the basic steps for characterization, column chromatography, FT-IR, GC/MS and SEM were used for further characterization. The results showed that liquid and solid products from pistachio shells show similarities with high value conventional fuels.

The pyrolysis of tea waste was studied for determining the main characteristics and quantities of liquid and solid products. Particular investigated process variables were temperature (673-973 K), heating rate (5-700 K min À1 ) and nitrogen gas flow rate (200-800 cm 3 min À1 ). The maximum oil and char yields are 30.4 (773 K) and 43.3% (673 K), respectively. The liquid and its aliphatic sub-fraction were characterized by elemental analysis, FT-IR, 1 H NMR, and GC/MS. The char was characterized with elemental analysis, SEM, BET, and FT-IR techniques. The aliphatic sub-fraction of the obtained bio-oil contains predominantly n-alkanes and alkenes, and branched hydrocarbons. According to the experimental results the liquid products can be used as liquid fuels, whereas the solid product seems to be not suitable for adsorption purposes, due to having low surface areas.

This study consists of producing high surface area activated carbon from tobacco residues by chemical activation and its behavior of phenol removal from aqueous solutions. K 2 CO 3 and KOH were used as chemical activation agents and three impregnation ratios (50, 75 and 100 wt.%) were applied on biomass. Maximum BET surface areas of activated carbons were obtained from impregnation with 75 wt.% of K 2 CO 3 and 75 wt.% of KOH as 1635 and 1474 m 2 /g, respectively. Optimum adsorption conditions were determined as a function of pH, adsorbent dosage, initial phenol concentration, contact time and temperature of solution for phenol removal. To describe the equilibrium isotherms the experimental data were analyzed by the Langmuir, Freundlich, Dubinin-Radushkevich (D-R) and Temkin isotherm models. Pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models were used to find out the kinetic parameters and mechanism of adsorption process. The thermodynamic parameters such as G • , H • and S • were calculated for predicting the nature of adsorption. According to the experimental results, activated carbon prepared from tobacco residue seems to be an effective, low-cost and alternative adsorbent precursor for the removal of phenol from aqueous solutions.

This study covers the thermal degradation of polycarbonate by means of Thermogravimetric Analyzer coupled with Fourier transform infrared spectrometer (TGA-FTIR). Thermogravimetric analysis of polycarbonate was carried out at four different heating rates of 5, 10, 15, and 20 °C per minute from 25 °C to 1000 °C under nitrogen atmosphere. The results indicated that polycarbonate was decomposed in the temperature range of 425-600 °C. The kinetic parameters, such as activation energy, pre-exponential factor and reaction order were determined using five different kinetic models; namely Coast-Redfern, Friedman, Kissinger, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS). Overall decomposition reaction order was determined by Coats-Redfern method as 1.5. Average activation energy was calculated as 150.42, 230.76, 216.97, and 218.56 kJ/mol by using Kissinger, Friedman, FWO, and KAS models, respectively. Furthermore, the main gases released during the pyrolysis of polycarbonate were determined as CO 2 , CH 4 , CO, H 2 O, and other lower molecular weight hydrocarbons such as aldehydes, ketones and carbonyls by using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer.

This study investigates the thermal decomposition behavior of cottonseed via TGA/FT-IR/MS and the quantification/characterization of liquid products from fast pyrolysis. Thermal degradation of the biomass sample has occurred in four steps, corresponding to the removal of moisture, decomposition of cellulose, hemicellulose and lignin and it was completed at about 700 • C. The main gaseous products evolved were CO 2 , light hydrocarbons and H 2 O. For the fast pyrolysis experiments, particular investigated process variables were temperature (400-700 • C), heating rate (5-700 • C min −1) and nitrogen gas flow rate (100-800 cm 3 min −1). Maximum oil yield was attained at 500 • C with a yield of 49.5% under 200 cm 3 min −1 nitrogen flow rate and at a heating rate of 300 • C min −1. Bio-oil obtained at optimum conditions are separated into its fractions by column chromatography. The oil and its sub-fractions were characterized by elemental analysis, FT-IR, and GC/MS. The char was characterized with elemental analysis and FT-IR techniques. The aliphatic sub-fraction of the obtained bio-oil contains predominantly straight chain of n-alkanes and alkenes. According to the chemical characterization, the bio-oil can be utilized as conventional liquid fuels.

This study covers the thermal degradation of polycarbonate by means of Thermogravimetric Analyzer coupled with Fourier transform infrared spectrometer (TGA-FTIR). Thermogravimetric analysis of polycarbonate was carried out at four different heating rates of 5, 10, 15, and 20 °C per minute from 25 °C to 1000 °C under nitrogen atmosphere. The results indicated that polycarbonate was decomposed in the temperature range of 425-600 °C. The kinetic parameters, such as activation energy, pre-exponential factor and reaction order were determined using five different kinetic models; namely Coast-Redfern, Friedman, Kissinger, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS). Overall decomposition reaction order was determined by Coats-Redfern method as 1.5. Average activation energy was calculated as 150.42, 230.76, 216.97, and 218.56 kJ/mol by using Kissinger, Friedman, FWO, and KAS models, respectively. Furthermore, the main gases released during the pyrolysis of polycarbonate were determined as CO 2 , CH 4 , CO, H 2 O, and other lower molecular weight hydrocarbons such as aldehydes, ketones and carbonyls by using thermogravimetric analyzer coupled with Fourier transform infrared spectrometer.

When using hemosorbent laminar flow, a large active area of sorbents is used, the trauma of the blood corpuscles decreases dramatically, the ash content of the saline solution is absent. One of the methods of solving environmental problems is to develop various materials based on industrial waste. In the article, the method of obtaining carbonized rice husks is described, the adsorption capacity for methylene blue was measured for the obtained sample, the morphological structure was examined, comparative analysis with analogs was carried out. The authors carried out research work, such as collecting information, selecting methods, conducting analysis, processing the results. Granular hemosorbents that have been used until recently penetrate the blood-forming elements, creating a mechanism for thrombosis that violates the integrity of the erythrocyte membrane. The experimental part of the research work on the effectiveness of next generation chemosorbents confirmed the apparent achievement of results and the rejection of new capabilities in a clinical approach to extracorporeal detoxifying modes of use and chemosorption by possession. The use of chemosorption as the main therapeutic option for headache disorders due to liver and kidney pathology has been identified in cases where other conditions are unsuccessful or ineffective. However, the use of fixed cost chemosorption in terms of treatment for patients remains unclear. The presence of chemical, hemodynamic, electrolytic, hormonal, immunological disorders prevents the prevalence of existing use in extracorporeal chemisorption.

This study reports the experimental results for the pyrolysis of pistachio shell under different conditions in a tubular reactor under a nitrogen flow. For the different conditions of pyrolysis temperature, nitrogen flow rate and heating rate, pyrolysis temperature of 773 K gave the highest bio-oil yield with a value of 27.7% when the heating rate and carrier gas flow rate were chosen as 300 K min À1 and 100 cm 3 min À1 ; respectively. Column chromatography was applied to this bio-oil and its subfractions were characterized by elemental analysis, FT-IR and 1 H-NMR. Aliphatic subfraction was conducted to gas chromatographymass spectroscopy for further characterization. The results for the characterization show that using pistachio shell as a renewable source to produce valuable liquid products is applicable via pyrolysis.

Climate change poses a fundamental threat to human prosperity, and thus solutions for both mitigation and adaptation strategies are becoming increasingly necessary. Biochar offers an interesting and eco-friendly carbon sequestration solution. However, it also raises a number of questions, regarding sustainable feedstock provision, biomass pyrolysis, and biochar amendment. These questions, among various others, are addressed in this state-of-the-art compendium. Covering a broad geographical range, this interdisciplinary volume includes regional assessments of biochar systems from North America, Europe, the Near East, and Southeast Asia. It focuses on the entire biochar supply chain, from the availability and economics of biomass resources, to pyrolysis, and ultimately to the impacts on soil properties when biochar is used as a soil amendment. The combination of theory with practical examples, including case studies and experiments, makes this a valuable book for researchers, policymakers, and graduate students alike, in fields such as soil science, sustainable development, climate change mitigation, biomass and bioenergy, forestry, environmental engineering, and pyrolysis.

Climate change is a rising threat for the entire world population. It makes future uncertain, especially in terms of provision of food and the usability of natural resources because a greater number and intensity of extreme weather events is expected as a consequence. Besides the direct physical damage such events may create on local scales, moderate, but persistent changes e.g. in temperature and precipitation, have the ability to change the capacities to produce enough food and consequently cause hunger, social inequalities and conflicts for resources. Although it is important to point out that there are both losers and winners in climate change scenarios, there is a good chance that the negative consequences dominate at the end of the day. There is no doubt in the scientific community that anthropogenic greenhouse gas (GHG) emissions are indeed playing a key role in rising global average temperatures during the last decades. Carbon dioxide (CO2) is put into center stage as it is ...

In the present work four different biomass samples (pine cone, soybean cake, corn stalk and peanut shell) were pyrolyzed to 550 • C in an inert gas atmosphere and a comparison between the properties of chars produced has been performed. Characterization of biomass samples was carried out with FT-IR, 13 C NMR, SEM and EDX. The influence of the parent material on char quality was investigated. The chars were characterized by their proximate and ultimate analysis and surface areas by N 2 adsorption at 77 K using BET equation. The morphological changes in carbonaceous solids were observed by scanning electron microscopy (SEM), and FT-IR spectra were obtained to evaluate the functional groups. The results obtained from the different techniques were combined to give an overview of the chemical and physical properties of the biomass char samples.

Biyokütlenin oksijensiz ortamda bozundurulması ile elde edilen piroliz katı ürünü (biyoçar), toprak kalitesini iyileştirici özelliğinden dolayı toprak düzenleyicisi olarak kullanılabilmektedir. Yapılan bu çalışmada, ceviz kabuğundan 500 °C'de biyoçar elde edilmiş ve biyoçar (g):toprak (kg) oranı 5, 10 ve 20 olmak üzere üç farklı oranda biyoçar-toprak karışımları hazırlanmıştır. Elde edilen karışımlar 3, 8 ve 12 haftalık sürelerde inkübasyona bırakılmış ve inkübasyon sonunda toprak örneklerinin karakterizasyonu için pH, elektriksel iletkenlik, katyon değiştirme kapasitesi (KDK) ve su tutma kapasitesi (STK) ölçümleri yapılmıştır. Taramalı Elektron Mikroskobu-Enerji-Dağılımlı X-Işını (SEM-EDX) tekniği ile inorganik madde miktarı ve Kjeldahl metodu ile azot miktarı belirlenmiştir. Yüksek karbon içeriğine ve gözenekli yapıya sahip olan biyoçar, toprağın elektriksel iletkenlik ve pH değerlerini önemli ölçüde azaltırken, azot miktarını ise artırmıştır. Toprak için su tutma kapasitesi yaklaşık 0.55 g/g olarak belirlenirken, biyoçar-toprak karışımında bu değerin 0.60 g/g'a yükseldiği görülmektedir. Biyoçarın bitki büyüme üzerindeki etkisi incelendiğinde, en verimli sonucun biyoçar (g):toprak (kg) oranının 5 olduğu örnekten elde edildiği belirlenmiştir. Anahtar Kelimeler-Biyokütle, Biyoçar, Ceviz Kabuğu, Toprak, pH bstract-Biomass can be used as a soil conditioner due to its soil quality enhancing properties. In this study, walnut shell biochar was produced at 500 °C and mixed with three different doses of soil, including biochar (g):toprak (kg) ratio are 5, 10 and 20. The obtained soil-biochar mixtures were incubated for 3, 8 and 12 weeks. Electrical conductivity, pH measurements, cation exchange capacity (CEC) and water holding capacity (WHC) were carried out to characterize soil samples at the end of incubation periods. The amount of nitrogen was determined by Kjeldahl method and Scanning Electron Microscope-Energy-Dispersive X-Ray (SEM-EDX) was used to specify the amount of inorganic substance in soil. The biochar with high carbon content and porous structure significantly reduced the pH and electrical conductivity values of the soil and increased the nitrogen amount. While the water holding capacity for the soil is determined as approximately 0.55 g/g, it is seen that this value increases to 0.60 g/g in the biochar-soil mixture. When the effect of biochar on plant growth was examined, it was determined that the most efficient result was obtained from 5 g of biochar/1 kg soil mixture.

H igh release of heavy metals from industries like metal processing, refining, paint, battery industry and mining causes serious wastewater contamination because of the non-degradable nature of metals. Released metal ions become poisonous for both plants and living organisms after certain concentrations since they tend to pile up in living organisms and cause various disturbances and disorders [1-4]. Hence, various physical and/or chemical treatment techniques have been applied for many years, such as chemical reduction, precipitation, solvent extraction, coagulation, flocculation and filtration, membrane processes [5-7]. However, feasible applications of the mentioned techniques are limited due to high operational and initial capital costs, low efficiency and production of undesirable sludge. Many of the mentioned techniques have substantial penalties, such as demand for high-priced equipment, high reagent consumption, high energy requirement, inadequate metal removal, and generation of toxic sludge. On the other hand, adsorption systems are rapidly gaining

This study covers the thermal degradation of polycarbonate by means of Thermogravimetric Analyzer coupled with Fourier transform infrared spectrometer (TGA-FTIR). Thermogravimetric analysis of polycarbonate was carried out at four different heating rates of 5, 10, 15, and 20 °C per minute from 25 °C to 1000 °C under nitrogen atmosphere. The results indicated that polycarbonate was decomposed in the temperature range of 425-600 °C. The kinetic parameters, such as activation energy, pre-exponential factor and reaction order were determined using five different kinetic models; namely Coast-Redfern, Friedman, Kissinger, Flynn-Wall-Ozawa (FWO), and Kissinger-Akahira-Sunose (KAS). Overall decomposition reaction order was determined by Coats-Redfern method as 1.5. Average activation energy was calculated as 150.42, 230.76, 216.97, and 218.56 kJ/mol by using Kissinger, Friedman, FWO, and KAS models, respectively. Furthermore, the main gases released during the pyrolysis of polycarbonate wer...

Preparation of activated carbons from Euphorbia rigida by chemical activation with different impregnation agents and ratios was studied. ZnCl 2 , K 2 CO 3 , NaOH and H 3 PO 4 were used as chemical activation agents and four impregnation ratios (25-50-75-100%) by mass were applied on biomass. Activation is applied to impregnated biomass samples at 700 • C under sweeping gas in a fixed bed reactor. For determination of chemical and physical properties of the obtained activated carbons; elemental analysis was applied to determine the elemental composition (C, H, N, O) and FT-IR spectra was used to analyze the functional groups. BET equation was used to calculate the surface areas of activated carbons. For understanding the changes in the surface structure, activated carbons were conducted to Scanning Electron Microscopy (SEM). Maximum BET surface area (2613 m 2 /g) was reached with 75% K 2 CO 3 impregnated biomass sample. Experimental results showed that impregnation types and ratios have a significant effect on the pore structure of activated carbon and E. rigida seems to be an alternative precursor for commercial activated carbon production.

We conjecture that the set of all Hilbert functions of (artinian) level algebras enjoys a very natural form of regularity, which we call the Interval Conjecture (IC): If, for some positive integer α, (1, h1, ..., hi, ..., he) and (1, h1, ..., hi +α, ..., he) are both level h-vectors, then (1, h1, ..., hi+ β, ..., he) is also level for each integer β = 0, 1, ..., α. In the Gorenstein case, i.e. when he = 1, we also supply the Gorenstein Interval Conjecture (GIC), which naturally generalizes the IC, and basically states that the same property simultaneously holds for any two symmetric entries, say hi and he−i, of a Gorenstein h-vector. These conjectures are inspired by the research performed in this area over the last few years. A series of recent results seems to indicate that it will be nearly impossible to characterize explicitly the sets of all Gorenstein or of all level Hilbert functions. Therefore, our conjectures would at least provide the existence of a very strong-and natural-form of order in the structure of such important and complicated sets. We are still far from proving the conjectures at this point. However, we will already solve a few interesting cases, especially when it comes to the IC, in this paper. Among them, that of Gorenstein h-vectors of socle degree 4, that of level h-vectors of socle degree 2, and that of non-unimodal level h-vectors of socle degree 3 and any given codimension.