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A Mathematical Model for Simultaneous Saccharification and Co-fermentation （SSCF） of C6 and C5 Sugars

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Chinese Journal of Chemical Engineering 2011年第2期19卷 185-191页

作者： Ricardo Morales-Rodriguez Krist V.gernaey Anne S.Meyer gürkan sin Computer Aided Process Engineering Center (CAPEC) Department of Chemical and Biochemical EngineeringTechnical University of DenmarkDK-2800 LyngbyDenmark PROCESS Department of Chemical and Biochemical EngineeringTechnical University of DenmarkDK-2800 LyngbyDenmark BIOENg Department of Chemical and Biochemical EngineeringTechnical University of DenmarkDK-2800 LyngbyDenmark

Reliable production of biofuels and specifically bioethanol has attracted a significant amount of re-search *** this context,this study deals with dynamic simulation of bioethanol production processes and in particular aims at developing a mathematical model for describing simultaneous saccharification and co-fermentation （SSCF） of C6 and C5 *** model is constructed by combining existing mathematical mod-els for enzymatic hydrolysis and *** inhibition of ethanol on cellulose conversion is introduced in order to increase the *** mathematical model for the SSCF is verified by comparing the model predic-tions with experimental data obtained from the ethanol production based on kraft paper mill *** fitting the model to the data,only the yield coefficients for glucose and xylose metabolism were fine-tuned,which were found to be 0.43 g·g-1 （ethanol/glucose） and 0.35 g·g-1 （ethanol/xylose） *** promising validation results encourage further model application to evaluate different process configurations for lignocellulosic bioetha-nol technology.

关键词： bioethanol dynamic modeling simultaneous saccharification and co-fermentation

Catalytic-kinetic spectrophotometric determination of vanadium (V) based on the Celestine blue-bromate-vanadium (V)-citric acid reaction

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Rare Metals 2011年第4期30卷 348-358页

作者： Ramazan gürkan Olcay gürkan Department of Chemistry Faculty of Sciences University of Cumhuriyet Sivas Fen Lisesi Emek mah. 64. Basari Sok. TR-58010 Merkez Sivas TURKEY

A novel sensitive and relatively selective kinetic method is presented for the determination of V（V） based on its catalytic effect on the oxidation reaction of Celestine blue by potassium bromate in the presence of citric acid as an activator. The reaction was monitored spectropho- tometrically by measuring the decrease in absorbance of Celestine blue at a maximum absorption wavelength of 540 nm between 0.5 and 9 min （the fixed-time method） in an H3PO4 medium at 45℃. The effect of various parameters such as concentrations of H3PO4, citric acid, potassium bromate and Celestine blue, ionic strength, reaction temperature and time on the rate of V（V） catalyzed reaction was studied. The method is free from the most interferences, especially from large amounts of V（IV）. The decrease in absorbance is proportional to the concentration of V（V） over the entire concentration range tested （0.025-1.25 ***^-1） with a detection limit of 6.80 tag.L^-1 （according to statistical 3Sblank/k criterion） and a coefficient of variation （CV） of 1.78% （for ten replicate measurements at 95% confidence level）. The proposed method suffers from a few interferences such as Cr（VI） and Hg（Ⅱ） ions. The method was successfully applied to the determination of V（V） in river water, lake water, tap water, natural drinking water samples and a certified standard reference material such as SRM-1640 with satis- factory results. The vanadium contents of natural water samples were detected by using both linear calibration curve and standard addition curve methods. The recoveries of spiked vanadium （V） into the certified standard water sample were found to be quantitative, and the reproducibility was satisfactory. It was observed that the results of the SRM 1640 were in good agreement with the certified value.

关键词： catalytic effect vanadium spectrophotometry bromates Celestine blue citric acid

Micellar sensitized catalytic kinetic spectrophotometry for highly accurate and reproducible determination of Ⅴ(Ⅳ) and Ⅴ(Ⅴ)

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Rare Metals 2014年第4期33卷 466-478页

作者： Ramazan grkan Can Emektas Department of Chemistry Faculty of SciencesUniversity of Cumhuriyet

A highly accurate and reproducible micellar sensitized kinetic method was proposed for determination of V（VI）. The method is based on its catalytic effect on the oxidation of Coomassie brilliant blue R 250 （CBB＋） by bromate at pH 2.0. The reaction was monitored spectro- photometrically by measuring absorbance change with a fixed-time method of 5 min at 594 and 552 nm with and without surfactant. The variables influencing the calibra- tion sensitivity were extensively investigated, and the optimal conditions were established. The linear calibration range was 10-1,600 μg.L-1 with a relative SD ranging from 0.35 % to 3.35 % （for five replicate measurements of 75, 500, 1,000, and 1,500 μg.L-1） and a detection limit of 3.8 μg.L-1. The selectivity was also investigated, and greatly enhanced by suitable masking agents. The method was successfully applied to the analysis of V（IV） in pre- sence of excess V（V） up to 25 fold in environmental waters with the recoveries of 100.0 %-102.8 % for V（IV） and 95.7 %-99.7 % for total V. Its accuracy was validated by analysis of certified reference material via the present kinetic method and standard flame atomic absorption spectrometric method after extractive preconcentration with good agreement between certified and found values.

关键词： Vanadium speciation Kineticspectrophotometry Bromate Coomassie brilliant blue R250 Micellar effect

A novel indicator system for catalytic spectrophotometric determination and speciation of inorganic selenium species (Se(Ⅳ), Se(Ⅵ)) at trace levels in natural lake and river water samples

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Rare Metals 2011年第5期30卷 477-487页

作者： Ramazan gürkan Halil brahim Ulusoy Mehmet Akay Pinar Bulut Department of Chemistry Faculty of Science University of Cumhuriyet

A novel catalytic kinetic method is proposed for the determination of Se（Ⅳ）, Se（Ⅵ）, and total inorganic selenium in water based on the catalytic effect of Se（Ⅳ） on the reduction of Celestine blue by sodium sulfide at pH 7.0 phosphate buffer. The fixed-time method was adopted for the determination and speciation of inorganic selenium. Under the optimum conditions, the two calibration graphs are linear with a good correlation coefficient in the range 2-20 and 20-200 μg·L-1 of Se（Ⅳ） for the fixed-time method at 30℃. The experimental and theo- retical detection limits of the developed kinetic method were found to be 0.21 and 2.50 μg·L-1 for the fixed-time method （3 min）. All of the variables that affect the sensitivity at 645 nm were investigated, and the optimum conditions were established. The interference effect of various cations and anions on the Se（Ⅳ） determination was also studied. The selectivity of the selenium determination was greatly improved with the use of the strongly cation exchange resin such as Amberlite IR120 plus as long as chelating agents of thiourea and thiosulphate. The proposed kinetic method was validated statistically and through recovery studies in natural water samples. The relative standard deviations （RSDs） for ten replicate measurements of 2, 10, and 20 μg·L-1 of Se（Ⅳ） change between 0.35% and 5.58%, while the RSDs for ten replicate measurements of 3, 6, and 12 μg·L-1 of Se（Ⅵ） change between 0.49% and 1.61%. Analyses of a certified standard reference material （NIST SRM 1643e） for selenium using the fixed-time method showed that the proposed kinetic method has good accuracy. The Se（Ⅳ）, Se（Ⅵ）, and total inorganic selenium in lake and river water samples have been successfully determined by this method after selective reduction of Se（Ⅵ） to Se（Ⅳ）.

关键词： selenium speciation Celestine blue catalytic effect kinetic spectrophotometry natural waters

Vibrational investigation of 1-cyclopentylpiperazine:A combined experimental and theoretical study

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Science China(Physics,Mechanics & Astronomy) 2014年第9期57卷 1654-1661页

作者： BAgLAYAN zge KESAN gürkan PARLAK Cemal ALVER zgür SENYEL Mustafa Department of Physics Science Faculty Anadolu University Institute of Physics and Biophysics Faculty of Science University of South Bohemia Department of Physics Dumlupinar University

FT-IR and Raman spectra of 1-cyclopentylpiperazine(1cppp)have been experimentally examined in the region of 4000–*** optimized geometric parameters,conformational equilibria,normal mode frequencies and corresponding vibrational assignments of 1cppp(C9H18N2)are theoretically examined by means of B3LYP hybrid density functional theory(DFT)method together with 6-31++g(d,p)basis *** the basis of potential energy distribution(PED)reliable vibrational assignments have been made and the thermodynamics functions,highest occupied and lowest unoccupied molecular orbitals(HOMO and LUMO)of 1cppp have been *** are employed for four different conformations in C1 and Cs point groups of 1cppp in gas *** between the experimental and theoretical results indicates that B3LYP method is able to provide satisfactory results for predicting vibrational frequencies and the structural parameters,vibrational frequencies and ***,C1(equatorial-axial)point group has been found as the most stable conformer of 1cppp.

关键词： 1-cyclopentylpiperazine vibrational spectra PED DFT B3LYP

An SPH Framework for Earthquake-Induced Liquefaction Hazard Assessment of geotechnical Structures

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 251-277页

作者： Sourabh Mhaski g.V.Ramana Department of Civil Engineering Indian Institute of Technology DelhiNew Delhi110016India

Earthquake-induced soil liquefaction poses significant risks to the stability of geotechnical structures *** understanding of the liquefaction triggering,and the post-failure large deformation behaviour is essential for designing resilient *** present study develops a Smoothed Particle Hydrodynamics(SPH)framework for earthquake-induced liquefaction hazard assessment of geotechnical *** coupled flowdeformation behaviour of soils subjected to cyclic loading is described using the PM4Sand model implemented in a three-phase,single-layer SPH framework.A staggered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energy modes and tensile ***,non-reflecting boundary conditions for seismic analysis of semi-infinite soil domains using the SPH method are *** numerical framework is employed for the analysis of cyclic direct simple shear test,seismic analysis of a level ground site,and liquefaction-induced failure of the Lower San Fernando *** agreement for liquefaction triggering and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading on field-scale geotechnical *** present study also serves as the basis for future advancements of the SPH method for applications related to earthquake geotechnical engineering.

关键词： Earthquake seismic liquefaction stress particle PM4Sand smoothed particle hydrodynamics(SPH)

Comparison of body mass index, anti-müllerian hormone and insulin resistance parameters among different phenotypes of polycystic ovary syndrome

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gynecology and Obstetrics Clinical Medicine 2022年第4期2卷 164-170页

作者： Türkan gürsu Alper Eraslan Berk Angun University of Health Sciences Turkey Zeynep Kamil Maternity and Children's Training and Research HospitalDepartment of Obstetrics and GynecologyIstanbulTurkey Dunya IVF Center KyreniaCyprus Department of Reproductive Endocrinology and InfertilityTurkey

Background:Diagnosis of polycystic ovary syndrome(PCOS)depends on 2003 Rotterdam *** to these criteria there are four possible combinations resulting in various *** aimed(i)to confirm that the levels of body mass index(BMI),anti-müllerian hormone(AMH)levels and insulin resistance(IR)are higher in PCOS patients and higher in phenotype-A among PCOS patients,and(ii)to determine cut-off values for the diagnosis of PCOS and *** and methods:This study was conducted in an IVF Center,between November 2019 and January *** of infertile women participating in the study was evaluated *** such as menstruation pattern,clinical hyperandrogenism,age,BMI,follicle stimulating hormone(FSH),luteinizing hormone(LH),estradiol,thyroid stimulating hormone(TSH),prolactin,AMH,dehydroepiandrosterone sulphate(DHEA-S),fasting blood glucose,fasting insulin levels,antral follicle counts(AFC)and ovarian volumes were recorded for each *** were grouped as PCOS and non-PCOS,and PCOS group was further divided into 4 subgroups according to their *** of infertile patients with PCOS patients were compared with infertile non-PCOS patients and PCOS phenotypes were compared among each ***:Data of 244 infertile patients was included in the ***,AMH,AFC,and HOMA-IR were statistically higher in PCOS patients,compared to non-PCOS *** found the AMH level of>3.105 ng/ml to be having 90.8%sensitivity and 90%specificity to diagnose a patient as *** different phenotypes,also BMI,AMH,and insulin resistance index(HOMA-IR)levels were significantly higher in infertile PCOS phenotype-A when compared to other three phenotypes(p:0.003,p:0.000,and p:0.000,respectively).The AMH cut-off value to estimate phenotype-A was found as 6.095 ng/ml with 69.2%sensitivity and 86.7%*** did not found threshold levels of BMI and HOMA-IR with high sensitivity to identify ***:Properly di

关键词： Polycystic ovarian syndrome Body mass index Anti-müllerian hormone Insulin resistance PCOS Phenotypes

Effect of Boron and Heat Treatment on Mechanical Properties of White Cast Iron for Mining Application

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Journal of Iron and Steel Research International 2011年第11期18卷 31-39页

作者： Havva Kazdal Zeytin Hakan Yildirim Banu Berme Selim Duduoglu gürkan Kazdal Adem Deniz TUBITAK MRC Duduoglu Steel Casting Industry and Trade Inc Co TuBITAK MRC Materials Institute Chemistry Metallurgy Faculty Istanbul Technical University

Heat treatment methods were applied to white cast iron for improving the impact and wear resistance. Additionally, chemical composition optimization was made. Furthermore, the effect of boron addition on such applica- tions was investigated. Samples were investigated by using optical and electron microscope methods. Hardness, wear and impact tests were conducted. The results showed that the secondary carbides in the standard alloy were iron-enriched, needle-like carbides M3C when the boron-added alloy contained Fe23 （C, B）6 type, globular secondary carbides. It was concluded that heat treatment B provided higher wear and hardness properties, compared to the stand- ard heat treatment. Optimum mechanical properties were obtained by lower destabilisation temperatures and increasing temperature reduced the wear resistance and hardness.

关键词： white cast iron mining application impact resistance wear toughness

Response of hydrological drought to meteorological drought in the eastern Mediterranean Basin of Turkey

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Journal of Arid Land 2021年第5期13卷 470-486页

作者： Türkan BAYER ALTIN Bekir N ALTIN Department of geography Faculty of Science and LettersNiğdeÖmer Halisdemir UniversityNiğde 51240Turkey

The hydrographic eastern Mediterranean Basin of Turkey is a drought sensitive *** basin is an important agricultural area and it is necessary to determine the extent of extreme regional climatic changes as they occur in this ***’s correlation coefficient was used to show the correlation between standardized precipitation index(SPI)and standardized streamflow index(SSI)values on different time *** from five meteorological stations and seven stream gauging stations in four sub-basins of the eastern Mediterranean Basin were analyzed over the period from 1967 to *** correlation between SSI and SPI indicated that in response to meteorological drought,hydrological drought experiences a one-year delay then occurs in the following *** is more evident at all stations from the mid-1990 *** main factor causing hydrological drought is prolonged low precipitation or the presence of a particularly dry *** showed that over a long period(12 months),hydrological drought is longer and more severe in the upper part than the lower part of the *** to SPI-12 values,an uninterrupted drought period is observed from 2002–2003 to 2008–*** indicated that among the drought events,moderate drought is the most common on all timescales in all sub-basins during the past 51 ***-term dry periods with moderate and severe droughts are observed for up to 10 years or more since the late 1990 s,especially in the upper part of the *** precipitation increases in late autumn and early winter,the stream flow also increases and thus the highest and most positive correlation values(0.26–0.54)are found in *** values(ranging between–0.11 and–0.01)are weaker and negative in summer and autumn due to low *** is more evident at all stations in *** relation between hydrological and meteorological droughts is more evident,with the correlation values above 0.50 on longer timescales(12-and 24-month

关键词： meteorological drought hydrological drought standardized precipitation index(SPI) standardized streamflow index(SSI) eastern Mediterranean Basin