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Koleksiyondaki öğeler
- MakaleAçık Erişim2019Scopus SJRQ2Effect of pH on Protein Extraction from Mahaleb Kernels and Functional Properties of Resulting Protein Concentrate
Güzel, Melih; Çelik, Mehtap; Yildirim, Metin
The aims of this research were to examine the effect of pH on extraction of proteins from mahaleb (Prunus mahaleb L.) kernels, and to investigate the functional properties of resulting protein concentrate. The optimum pH values for the protein extraction and precipitation were determined as 10.0 and 4.5, respectively. The protein concentrate containing 92.73% dry matter, 6.29% ash, 6.02% carbohydrate, 1.42% fat and 73.11% protein was produced by using these extraction and precipitation pH values. Water-holding capacity, oil-holding capacity and the least gelling concentration of the protein concentrate were 2.81 g water/g, 1.66 g oil/g and 12%, respectively. Moreover, emulsifying activity and stability indices, foaming capacity and stability of protein concentrate were 27.21 m2/g, 81.05 min, 43.75% and 71.33% (after 30 min), respectively. The functional and chemical properties of the protein concentrate indicate that it may find application as functional ingredient for various food products.
AtıfScopus9WoS8OpenAlex7İncele - MakaleYalnız künye2019Scopus SJRQ1A new colorimetric method for CUPRAC assay with using of TLC plate
Akar, Zeynep; Burnaz, Nesibe Arslan
Cupric reducing antioxidant capacity (CUPRAC) method is one of the most widely used antioxidant methods. However, its need for a spectrophotometer, as in many other methods, is an important disadvantage. Cupric reducing antioxidant capacity was determined based on color analysis with Image J program in computer with the new method developed in this study and thus, use of spectrophotometer was eliminated. The new colorimetric CUPRAC assay was applied to various standard antioxidants and plant extracts. The reaction mixtures were dropped on TLC plate. The colors formed on TLC were transferred to the computer by using scanner images, and CTEAC value in μmol/L of each sample was determined with the image J program. The CTEAC values were compared with the TEAC values measured with the spectrometric method. A linear relationship was found between both (C)TEAC values of antioxidant standards (R2 = 0.991) and plant extracts (R2 = 0.994). Thus, the new method developed for the CUPRAC antioxidant assay can be easily performed in any environment without spectrophotometer device, and it is a low-cost method.
AtıfScopus17WoS15OpenAlex25İncele - MakaleAçık Erişim2017Scopus SJRQ2Effect of brewing conditions on antioxidant properties of rosehip tea beverage: study by response surface methodology
İlyasoğlu, Huri; Arpa, Tuba Eda
The aim of this study was to investigate the effects of brewing conditions (infusion time and temperature) on the antioxidant properties of rosehip tea beverage. The ascorbic acid content, total phenolic content (TPC), and ferric reducing antioxidant power (FRAP) of rosehip tea beverage were analysed. A two-factor and three-level central composite design was applied to evaluate the effects of the variables on the responses. The best quadratic models were obtained for all responses. The generated models were validated under the optimal conditions. At the optimal conditions, the rosehip tea beverage had 3.15 mg 100 mL−1 of ascorbic acid, 61.44 mg 100 mL−1 of TPC, and 2591 µmol of FRAP. The best brewing conditions for the rosehip tea beverage were found to be an infusion time of 6–8 min at temperatures of 84–86 °C.
AtıfScopus31WoS23OpenAlex33İncele - Kitap BölümüYalnız künye2019Scopus SJRQ3COPRAS method with neutrosophic sets
Şahin, Rıdvan
Interval neutrosophic number (INN), which is descripted by the degree of truth-membership, indeterminacy-membership and falsity-membership of an element, is a powerful information tool with many application areas. The purpose of this study is to develop an extended form of COPRAS (Complex Proportional Assessment) method used for solving the decision making problems in which all the data presented by decision makers is in the form of interval neutrosophic matrix presented by INNs, and the information about criterion weights is partially known or completely unknown. In order to accomplish this goal, a new score function and an accuracy function that consider the decision maker’s risk attitude are defined under a parameter called the risk index to determine the ordering of INNs. Then, based on Maclaurin symmetric mean (MSM) operator that can capture the interrelationships among multi-input arguments, some aggregation operators are defined, such as interval neutrosophic Maclaurin symmetric mean (INMSM) operator and interval neutrosophic weighted Maclaurin symmetric mean (INWMSM) operator. Moreover, some optimization models are established to determine the subjective and objective weights of decision criteria. A numerical problem is solved to demonstrate the effective and feasible structure of the developed method. Then, a sensitive analysis is conducted according to the decision maker’s risk attitude, and the advantages of the developed method are listed. Finally, a comparison analysis is provided to present the relationships among the developed method and existing methods, and some conclusions are given at the end of the study.
AtıfScopus6OpenAlex6İncele - MakaleAçık Erişim2019Scopus SJRQ4Presence of different bacterial species in thermal sources and novelty in their industrial enzyme productions
Albayrak, Seyda; Genc, Berna; Ozkan, Hakan; Taskin, Mesut; Adiguzel, Ahmet
In this study, one hundred and thirty isolates were isolated from water and sludge samples taken from hot springs located in different regions of Turkey. Among them, eleven isolates were chosen according to conventional (morphological, physiological and biochemical tests) and molecular methods (rep-PCR and 16S rRNA sequencing). These bacteria were then tested for their capability to produce valuable enzymes. As a result; species belonging to Bacillus, Anoxybacillus, Aeribacillus, Enterococcus, Exiguobacterium and Paenibacillus were identified. Test strains were found to have optimum reproductive potential at pH 5.0-9.0 and 15-65°C, usually at a concentration of 1.0-10.0% (w/v) NaCl. In addition, all thermotolerant bacteria were Gram, endospore (except E. profundum), catalase and oxidase (except E. faecium and E. profundum) positive, and rod-shaped (except E. faecium). It was observed that all isolates had a 99% similarity percentage as a result of 16S rRNA sequence analysis. All of the isolates were capable of producing industrially important enzymes moreover, eight of them could produce at least two of these enzymes. Test strains had high potential of industrial enzyme production, and the enzymes from these thermo-tolerant isolates will be widely used in biotechnological processes.
AtıfScopus7WoS7OpenAlex7İncele - MakaleYayıncıda açık erişim2016Scopus SJRQ3The effects of Co addition on the mechanical and microstructural properties of the matrix material of a Fe-based marble cutting tool
Budak, S.; Kaplan, M.
In this study, four different kinds of marble cutting matrices with a base composition of Fe-Cu-Sn and with variable amounts of Co powder were produced. For compaction, hot sintering process was carried out at 850°C under 35 MPa for 4 min. The mechanical and microstructural properties of the matrix materials were determined using SEM with EDS, three-point bending test, density and hardness measurement techniques. The addition of Co powders to the matrix and the subsequent hot sintering process affected the mechanical and microstructural properties of the cutting tool, such as hardness, total elongation, % porosity and phase distribution.
- MakaleYalnız künye2016Scopus SJRQ1Effect of seasonal changes on the combustion characteristics of impregnated cedar (Cedrus libani A. Rich.) wood
Fidan, M. Said; Yaşar, Ş. Şadiye; Yaşar, Mehmet; Atar, Musa; Alkan, Elif
Wood is an irreplaceable material used as decorative and structural element both indoors and outdoors. When used as a structural material, wood has several superior characteristics in comparison to other structural constituents, although it is adversely affected by fires as well as biotic pests and abiotic effects. In this study, cedar (Cedrus libani A. Rich.) wood samples were impregnated using either Tanalith-E or Wolmanit-CB as detailed in ASTM-D 1413-76 and surface-treated using water-based or synthetic varnish. The impregnated and varnished samples were left outdoors with the aim of investigating the effect of seasonal changes. The samples were later subjected to combustion analysis as detailed in the combustion test standard ASTM-E 160-50. The results of the study indicated that the weight loss was lower during winter (87.82%), for samples that were impregnated using Wolmanit-CB (88.90%) and those that were treated with synthetic varnish (88.45%). On the other hand the O2 and CO2 contents were determined to be the highest in fall during combustion without flame (18.16% and 17.96%, respectively); the CO content was the highest during combustion without flame for the winter samples (28,907 ppm) and the NO content was the highest during combustion without flame for the spring samples (76.15 ppm). In conclusion, the winter samples that were impregnated using Wolmanit-CB and treated with synthetic varnish were determined to be safer to employ in areas with high fire risk.
AtıfScopus6WoS9OpenAlex5İncele - MakaleYalnız künye2018Scopus SJRQ2Evaluation of Pomological and Morphological Characteristics and Chemical Compositions of Local Pear Varieties (Pyrus communis L.) Grown in Gumushane, Turkey; [Pomologische und morphologische Eigenschaften sowie Inhaltsstoffe lokaler Birnensorten (Pyrus communis L.) in Gumushane (Türkei)]
Kalkisim, Ozgun; Okcu, Zuhal; Karabulut, Besim; Ozdes, Duygu; Duran, Celal
The aim of the present research was to investigate the fruit quality of twenty different local pear varieties (Pyrus communis L.), namely Ahlat, Ankara, Arpa, Bıldırcın, Çermai, Cinci, Gelin Boğan, Hacı Hamza, Hahır, Kabak, Kızıl, Kokulu, Mehrani, Menendi, Sulu, Şalgam, Tokat Sultanı, Turşu, Yaz, and Yaz Meyriği, grown in Gumushane province in terms of pomological and morphological characteristics and chemical compositions. The fruit mass, fruit width and length, fruit stem thickness and length, fruit kernel width and length, hardness of pulp, number of seeds, leaf width and length, leaf stem length and thickness, and water soluble dry matter (WSDM) of the pear fruits have been determined as pomological and morphological characteristics. On the other hand, the chemical compositions of the pear varieties have been evaluated in terms of protein, ash, sucrose, fructose, glucose, total sugar, titratable acidity, moisture, and mineral element levels. Both pomological and morphological results demonstrated that the local pear varieties are important in terms of rehabilitation studies and detailed selection studies on these local varieties should be performed. The chemical analyses result of the pear varieties revealed that there is no component that may be harmful to human health when consumed, and also these varieties contains the necessary amount of mineral elements.
AtıfScopus10WoS10OpenAlex20İncele - MakaleYalnız künye2018Scopus SJRQ1Dynamic response of a historical armory building using the finite element model validated by the ambient vibration test
Altunişik, Ahmet Can; Genç, Ali Fuat; Günaydin, Murat; Okur, Fatih Yesevi; Karahasan, Olguhan Şevket
In this paper, the aim was to determine the nonlinear dynamic response of historical masonry armory buildings using a validated finite element model. Eight ambient vibration tests were conducted on the building, using three different measurement test setups to extract the dynamic characteristics using the Enhanced Frequency Domain Decomposition method. A finite element model was constructed in ANSYS and the dynamic characteristics were obtained numerically. It can be seen that there is a good correlation between the mode shapes, but there are differences in natural frequencies with maximum values of 10.1%, 7.4% and 13.4% for first the three modes. To determine the nonlinear dynamic response, the validated finite element model was analyzed using the Kocaeli earthquake motion. The Drucker–Prager criterion and Willam–Warnke surface were considered for the nonlinear material models. At the end of the analyses, maximum displacements, principal stresses and strains are given in detail using contour diagrams. It is evident that the displacements show an increasing trend from the base to the top point of the building. Stresses occurred on the corners, openings and transition segments. In addition, crack distribution diagrams were drawn up to illustrate the stress accumulation points.
AtıfScopus26WoS25OpenAlex23İncele - Derleme MakaleYalnız künye2019Scopus SJRQ2Automation in the Mining Industry: Review of Technology, Systems, Human Factors, and Political Risk
Rogers, W. Pratt; Kahraman, M. Mustafa; Drews, Frank A.; Powell, Kody; Haight, Joel M.; Wang, Yaxue; Baxla, Kritika; Sobalkar, Mohit
In the opinion of these authors, technology alone can never give an organization an edge over competitors or provide an industry step change. However, history has shown that technology applied with correct logistics and strategy makes a significant difference. Never has the minerals industry faced such daunting challenges and been in such need of a step change. Application of autonomous systems has been steadily increasing in the minerals industry. Automation technology has changed the mining value chain from exploration to mineral processing and refining. The future state will only see additional in-roads of automation into more processes and the whole system design. To better understand the near-future potential of automation, it is useful to explore and review the current state of automation in minerals development. A review of the state of automation research is given. The review will consider three critical areas: automation technology, system’s engineering and management processes around automation, and the role of human factors engineering in automated and semi-automated systems. The review ends with a discussion on the social and political risks of automation in terms of shared value and sustainable development.
AtıfScopus95WoS70OpenAlex75İncele - MakaleYayıncıda açık erişim2016Scopus SJRQ1Organic geochemistry and element distribution in coals formed in eocene lagoon facies from the Eastern Black Sea Region,NE Turkey
Saydam Eker, Çiğdem; Akpinar, İbrahim; Sipahi, Ferkan
The amount and type,the inorganic element content,and the maturity of organic materials of Eocene coals,shaly coals,and coaly shales exposed in the Gümüşhane and Bayburt districts of the Eastern Black Sea Region of Turkey were investigated. The depositional environments and hydrocarbon potentials were also interpreted. The total organic carbon concentrations in the studied samples ranged from 0.50% to 63.08%. The samples from Özyurt,Kayadibi,and Tarhanas contained types II and III kerogen,and those from Sökmen and Manas contained type III kerogen. The samples contained Co,Cs,Ga,Hf,Th,U,Y,Mo,Be,Cd,Sb,and La,with average values similar to those of standard brown coals. The samples showed average contents of Co,Ga,Nb,Rb,V,Y,Cu,Pb,Zn,As,Be,and Se,similar to those of other Turkish coals. The sediment source of Eocene samples in the five areas was characterized by rocks with intermediate or mafic geochemical characteristics. The terrigenous/aquatic ratio of coal and shaly coal samples of the areas in question is >1. The sterane distribution was C29 > C28 > C27 and C29 > C27 > C28 for the Özyurt and Tarhanas areas,respectively. The average Tmax values for samples are between 424 °C and 460 °C. For samples Oz-1 and Ta-2,22S/(22S + 22R) homohopane (C32) ratios are 0.48 and 0.61,respectively; 20S/(20S + 20R) sterane (C29) ratios are 0.18 and 0.53,respectively; and Ts/(Ts + Tm) ratios are 0.015 and 0.64,respectively. The Pr/Ph ratios of the samples are >3. The studied samples have low sterane/hopane and high (C19+C20)/C23) ratios without anoxic biomarkers (17α(H)-28,30-bisnorhopane). Based on these data,the coals,shaly coals,and coaly shales were probably deposited under an oxic-suboxic mixture of marine and terrestrial environment conditions; these materials contain terrestrial organic matter and cannot generate hydrocarbon.
AtıfScopus15WoS16OpenAlex22TR Dizin4İncele - MakaleAçık Erişim2016Scopus SJRQ2Optimum Tuning of a Gyroscopic Vibration Absorber Using Coupled Gyroscopes for Vibration Control of a Vertical Cantilever Beam
Ünker, F.; Çuvalci, O.
This paper deals with the investigation of optimum values of the stiffness and damping which connect two gyroscopic systems formed by two rotors mounted in gimbal assuming negligible masses for the spring, damper, and gimbal support. These coupled gyroscopes use two gyroscopic flywheels, spinning in opposing directions to have reverse precessions to eliminate the forces due to the torque existing in the torsional spring and the damper between gyroscopes. The system is mounted on a vertical cantilever with the purpose of studying the horizontal and vertical vibrations. The equation of motion of the compound system (gyro-beam system) is introduced and solved to find the response measured on the primary system. This is fundamental to design, in some way, the dynamic absorber or neutralizer. On the other hand, the effect of the angular velocities of the gyroscopes are studied, and it is shown that the angular velocity (spin velocity) of a gyroscope has a significant effect on the behavior of the dynamic motion. Correctness of the analytical results is verified by numerical simulations. The comparison with the results from the derivation of the corresponding frequency equations shows that the optimized stiffness and damping values are very accurate.
AtıfScopus4WoS2OpenAlex5İncele - MakaleAçık Erişim2017Scopus SJRQ4The effect of sintering in different atmospheres on superconductivity parameters of YBCO
Başoǧlu, Mehmet
YBa2Cu3O7 (Y123) is a superconductor material discovered in 1987 and its transition temperature is above the liquid nitrogen temperature. It is known that superconductor samples produced by the solid-state reaction route are very often sintered in air atmosphere. However, in the presented work, Y123 was prepared by the same technique using a sintering ambient composed of a mixture of oxygen and argon gases for the first time. Critical current densities of the samples were calculated using results of magnetization measurements. It was obtained from magnetization analysis that all the samples exhibited superconductor character. It was also observed that the sample sintered in the 50% oxygen and 50% argon atmosphere showed the highest critical current density.
AtıfOpenAlex1İncele - BildiriYalnız künye2016Determination of the ground-building relationships in the KTU campus area with microtremor measurements
Beker, Y.; Sayil, N.; Akin, O.; Coban, K.H.
Microtremor measurement obtained by ground vibrations is one of the useful methods for determination of ground characteristics. Also the method has been using to specify building resonance risk during earthquakes in the last decades. In this study, single station microtremor recordings have been taken on the ground and at the 6 buildings in the KTU campus area. The measurements taken on the ground and in the buildings have been evaluated by Nakamura (H/V ratio) method. The eastern of the campus area presents Class-IV and the middle and western part of the campus present Class-II- Class-III according to Kanai and Tanaka ground classification. The predominant frequencies of the buildings are not in a harmony with the values of the ground. It can be deduce that the resonance risk is low for these buildings during the earthquakes. The H/V ratios of the ground change between 1-3 and lower than the buildings ratios which change between 5.0-8.5.
AtıfScopus1İncele - MakaleAçık Erişim2017Scopus SJRQ1A new colorimetric DPPH• scavenging activity method with no need for a spectrophotometer applied on synthetic and natural antioxidants and medicinal herbs
Akar, Zeynep; Küçük, Murat; Doğan, Hacer
2,2-Diphenyl-1-picrylhydrazyl (DPPH•) radical scavenging, the most commonly used antioxidant method with more than seventeen thousand articles cited, is very practical; however, as with most assays, it has the major disadvantage of dependence on a spectrophotometer. To overcome this drawback, the colorimetric determination of the antioxidant activity using a scanner and freely available Image J software was developed. In this new method, the mixtures of solutions of DPPH• and standard antioxidants or extracts of common medicinal herbs were dropped onto TLC plates, after an incubation period. The spot images were evaluated with Image J software to determine CSC50 values, the sample concentrations providing 50% colour reduction, which were very similar with the SC50 values obtained with spectrophotometric method. The advantages of the new method are the use of lower amounts of reagents and solvents, no need for costly spectrophotometers, and thus significantly lowered costs, and convenient implementation in any environment and situation.
AtıfScopus188WoS143OpenAlex169İncele - MakaleYalnız künye2017Scopus SJRQ1An injectable alginate-based hydrogel for microfluidic applications
Akay, Seref; Heils, Rene; Trieu, Hoc Khiem; Smirnova, Irina; Yesil-Celiktas, Ozlem
The objective of this study was to develop an injectable alginate based formulation for immobilizing enzymes into microfluidic systems. The gelation was induced upon lowering the pH by addition of D-glucono-δ-lactone (GDL) and release of Ca+ ions from solid CaCO3. The effects of GDL concentration on enzymatic activity and gelation time were investigated. The results indicated that increasing the GDL concentration increased both surface area and enzymatic activity. Also, chitosan was added to the formulation at different ratios to enhance the stability of enzyme during immobilization. For microfluidic application, 100 μl spiral coil single channel microchip was fabricated and alginate GDL mixture containing β-glucosidase was injected to the microchannel prior to gelation. Enzymatic conversion was performed by pumping substrate (pNPG) through the microchannel. The results indicated that the entire substrate was converted continuously during 24 h without any leakage or deactivation of immobilized enzyme.
AtıfScopus42WoS34OpenAlex38İncele - MakaleYalnız künye2019Scopus SJRQ2Exploring the value of using data: a case study of continuous improvement through data warehousing
Rogers, W. Pratt; Kahraman, M. Mustafa; Dessureault, Sean
The mining industry is adapting data-rich technology. Data management processes and infrastructure require additional investment which, can be difficult to justify. A valuation model for data management infrastructure would necessitate modelling the ‘use’ of data and quantifying the value and the likelihood of success of improvement initiatives. A model is presented which can assess the impacts of a data-driven initiative. The initiatives are shown to be the foundation of improved shift coordination resulting in significant and sustained operational improvements. This paper aims to illustrate the value of using data from source systems in mining operations.
AtıfScopus9WoS8OpenAlex11İncele - MakaleYalnız künye2017Scopus SJRQ1An Investigation of the Seismic Behaviour of an Ancient Masonry Bastion Using Non-Destructive and Numerical Methods
Altunisik, A.C.; Adanur, S.; Genc, A.F.; Gunaydin, M.; Okur, F.Y.
Determining the structural behavior of masonry structures is a challenge due to their lack of homogeneity. The seismic behavior of masonry structures is especially complex. The aim of this study was to examine the structural behavior of Zağanos Bastion using both experimental and numerical methods. The Operational Modal Analysis technique, including the Enhanced Frequency Domain Decomposition Method, and the Stochastic Subspace Identification Method were used to illustrate experimentally the dynamic characteristic of the bastion. A finite element model was developed using ANSYS software in order that the dynamic characteristics of the bastion, including natural frequencies and mode shapes, could be calculated numerically. Seismic analysis was carried out using the 1999 Kocaeli earthquake ground motion record to determine the linear and nonlinear seismic behavior of the bastion. The Turkish Earthquake Code and its general technical specifications were used to evaluate the seismic results. The results show that the maximum and minimum principal stresses exerted on the masonry components exceeded the code requirements at some points, but in general the requirements for the stresses were satisfied.
AtıfScopus22WoS22OpenAlex19İncele - BildiriYalnız künye2018Generalized beta parameters for a SVEIR-type random model of Polio transmission
Bekiryazici, Zafer; Merdan, Mehmet; Kesemen, Tulay
In this study, a SVEIR-type compartmental model of Poliomyelitis transmission is examined under random effects. We introduce Generalized Beta and normal distributed random parameters into the equation system to investigate the random dynamics of the disease. The approximate analytical solution of the model under random effects is obtained by using Random Differential Transformation Method (RDTM). Results from simulations and RDTM are analyzed to comment on the randomness of the compartments and disease transmission. It is seen that the random model successfully provides similar results that can be obtained through the deterministic model while providing additional information on the random behavior of the disease, such as the standard deviations and the variation coefficients.
AtıfScopus1WoS1İncele - MakaleAçık Erişim2016Scopus SJRQ1Comparison of practices related to occupational health and safety in microscale wood-product enterprises
Top, Yener; Adanur, Hakan; Öz, Mehmet
Risk factors in the workplace vary according to the sector and scale of the business. Small and medium-sized enterprises, especially those within the scope of the wood-products manufacturing industry, are considered to be risky, and have a relatively high accident rate. Here, we focus on the timber and furniture industries, two subsectors of the wood-products industry. A total of 47 enterprises was visited and asked to participate in a formal structured questionnaire. The findings show that the usage of personal protective equipment (PPE) was low, that lighting was often inadequate, and that these enterprises typically lacked routine organising and cleaning practices. The subsectors and the occupational health and safety practices were found to be independent, and a statistically significant relationship could only be established between the subsectors in terms of the use of dust masks and goggles. Despite the unfavourable working conditions, only one business out of 47 reported having an employee with symptoms of occupational diseases.
AtıfScopus33WoS30OpenAlex38İncele
