Gümüşhane ÜniversitesiGümüşhane ÜniversitesiAçık Erişim Arşivi · RDL Open

Sürdürülebilir Kalkınma Amaçları

Yazarlar

Yayınlar

Yeniden eskiyeEskiden yeniye
  • MakaleYalnız künye2021
    The performance of wong-zakai approximations for the investigation of stochastic differential equation models with nonlinear multiplicative noise

    Sengul, S.; Bekiryazici, Z.; Merdan, M.

    In this study, Wong-Zakai approximation method has been applied for the analysis of stochastic differential equations appearing in engineering sciences. Wong-Zakai approximation has been used with similar stochastic approximation methods to compare the approximate solutions of the problems and comment on the performance of the method. Models for lake pollution and computer virus spread under antivirus protection have been used with nonlinear stochastic noise as numerical examples to demonstrate the efficiency of Wong-Zakai method.

    İncele
  • MakaleYalnız künye2021
    Effects of puzzolanic materials in surface paste disposal by pilot-scale tests: observation of physical changes

    Bascetin, A.; Adiguzel, D.; Eker, H.; Odabas, E.; Tuylu, S.

    There are only a few pilot schemes, especially among scientific studies carried out to solve numerous environmental and ecological problems created by water during tailing storage on the surface. It is extremely important to establish precautions that can be taken, especially in the tailing storage process by examining the physical, chemical, mineralogical, and geotechnical changes that develop due to the effect of moisture in the tailing and surface water. In this study, 2 different pilot-scale designs of storage with no additions (reference) and with binder additions (cement and fly ash) to some layers were observed in field conditions for about 1 year to determine the effects of seasonal changes on paste material. The results of the measurements revealed that the water content of the reference design was ~ 10% higher than that of the design with cement addition at the substrates that provide stability and sudden temperature changes at the top layer of the reference design was found to be ~ 35 °C. Maximum sudden temperature changes in layers with cement addition and layers with cement and fly ash addition were observed to be ~ 15 °C. As a result, the use of cement has made the material more resistant to external factors. However, the study also revealed that fly ash could be used instead of cement with a substitute rate of 50% to reduce the cost for long-term storage in terms of industrial applications.

    • SDG 12 · Sorumlu Üretim ve Tüketim
    İncele
  • MakaleYalnız künye2021
    The effect of homocysteine on the expression of CD36, PPARγ, and C/EBPα in adipose tissue of normal and obese mice

    Mentese, Ahmet; Dogramaci, Seniz; Demir, Selim; Yaman, Serap Ozer; Ince, Imran; Altay, Diler Us; Erdem, Mehmet; Turan, Ibrahim; Alver, Ahmet

    The purpose of this study was to investigate the effect of homocysteine (Hcy) on CD36, PPARγ, and C/EBPα gene and protein expression in adipose tissue obtained from normal and high-calorie diet obesity models. CD36, PPARγ, and C/EBPα gene expression and protein levels in adipose tissue specimens were determined using the RT-PCR and ELISA methods, respectively. Significantly increased CD36 gene expression was observed in adipose tissue from obese mice, while Hcy significantly reduced CD36 gene expression in adipose tissue from normal and obese mice. PPARγ and C/EBPα gene expression levels decreased significantly in all groups compared to the normal group. In addition, levels of both PPARγ and C/EBPα gene expression were lower with Hcy supplementation compared to their own controls. In conclusion, Hcy’s reduction of CD36 gene expression in adipose tissue may be one probable factor in hyperhomocysteinemia representing an independent risk factor for cardiovascular diseases.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    İncele
  • MakaleAçık Erişim2021
    Determination of the effect of wheat germ on the mineral and fatty acid composition and aroma compounds of tarhana: A traditional fermented cereal food

    Tekgül, Yeliz; Çalışkan Koç, Gülşah; Erten, Edibe Seda; Akdoğan, Arda

    In this study, to supply to the trend toward natural and functional foods that do not include synthetic products, the wheat germ which exists as waste in nature was added to tarhana formulation in order to increase the nutritional content of tarhana. Wheat germ supplemented tarhana samples met the recommended dietary allowances of iron. A total of 63 compounds were detected and quantitated in all samples. Terpenes and terpenoids were observed as the dominant compound group. The addition of wheat germ to tarhana dough resulted in an increase in the number of volatile compounds. The most abundant odor-active compounds were acetic acid and 2-acetylpyyrole.The mineral (Mg, K, Zn, Mn), fatty acid (undecaenoic, linoleic, gondoic acid, and α-linolenic), oil, acid (propanoic and hexanoic), alcohol (linalool, benzyl, phenylethyl), aldehyde ((E)-2-heptenal, nonanal, 5-methyl-2-phenyl-2-hexenal), ketone (3-Octen-2-one), terpene (junipene, citronellol, trans-Carveol) contents of tarhana samples can be increased by addition of the wheat germ. Practical applications: The wheat germ which exists as waste in nature and contains a high amount of essential amino acids, proteins, fatty acids, minerals, dietary fiber, vitamins, etc. Wheat germ can be added to cereal-based food formulation such as tarhana in order to supply to the trend toward natural and functional foods that do not include synthetic products. Tarhana (basically made from yogurt, wheat flour, herbs, tomato, pepper, onion, etc.) which is a traditional fermented dry Turkish soup is rich in vitamins, minerals, and proteins. Wheat germ based-fermented products such as Tarhana may be considered promising new functional foods due to its probiotic effects in order to expand the market due to the increasing trend toward functional foods.

    İncele
  • MakaleAçık Erişim2021
    Crank-nicolson difference scheme for reverse parabolic nonlocal problem with integral and neumann boundary conditions

    Ashyralyyev, Charyyar; G¨onenc¸, Ahmet

    In this paper, we study Crank-Nicholson difference scheme for approximate solutions of parabolic nonlocal reverse problem with integral and Neumann boundary conditions. Stability estimates for its solution are established. Via Mathlab framework, we give numerical example with explanation on computer realization.

    İncele
  • MakaleAçık Erişim2021
    A comprehensive spatiotemporal evaluation of the current earthquake activity in different parts of the Frakull-Durrës fault zone, Albania

    Öztürk, Serkan; Ormeni, Rrapo

    This study presents a detailed spatiotemporal analysis for the Frakull-Durrës (F-D) fault zone at the beginning of 2020. For this purpose, the most frequently used statistical seismicity parameters such as magnitude completeness, Mc-value, Gutenberg-Richter b-value, recurrence times, annual probabilities and standard normal deviate, Z-value, were mapped. The F-D fault zone was divided into two seismogenic subregions, and Mc-value was taken as 2.5 for both the south and north parts. The b-value was estimated as 0.83 ± 0.06 for the south part and 0.85 ± 0.06 for the north part. b-values for both zones are smaller than 1.0 and these values may be considered to be a larger stress accumulation to build up over time and to be released by the next possible earthquakes. Clear decreasing trends were observed in time variations of b-values before the occurrences of several strong main shocks. Analyses of annual probabilities and recurrence times suggest that the study region has an intermediate/long-term earthquake hazard in comparison to occurrences of strong/destructive earthquakes in the short term. Some anomaly regions of a small b-value and a large Z-value were found along the F-D fault zone at the beginning of 2020: i) among Lushnje-Tirana-Durrës including the middle part of the F-D fault zone, ii) in and around Lezha including the north end of the F-D fault zone. Thus, the combination of regions with the lowest b-value and largest Z-value may supply preliminary results for earthquake hazard, and these regions may be considered to be the most likely regions for future strong/large earthquakes in the F-D fault zone.

    İncele
  • MakaleAçık Erişim2021
    A Data-Driven Approach to Control Fugitive Dust in Mine Operations

    Kahraman, Muhammet Mustafa; Erkayaoglu, Mustafa

    Particulate matter (PM) is one of the main actors related to air pollution caused by surface mining. Fugitive dust, considered as particulate matter that cannot be collected by conventional measures, is classified by the particle size. The Environmental Protection Agency (EPA) categorizes PM as coarse and fine particles based on the particle size being less than 10 μm (PM10) and less than 2.5 μm (PM2.5). Basic operations of surface mining such as drilling and blasting, loading, haulage, and processing are processes that can potentially generate fugitive dust. Regulations and legislations enforce the mining industry to use environmental monitoring systems, fugitive dust level measured by PM10 level as part of this. Air quality monitors are positioned at different locations around surface coal mines and track air quality levels during production. This study introduces a data-driven methodology to handle air quality issues related to fugitive dust at surface coal mines. Data is sourced from different mine equipment in real-time and they are integrated with air quality monitoring systems to provide information to support decisions for fugitive dust. The method is implemented and demonstrated in a case study at a large surface coal mine.

    İncele
  • MakaleAçık Erişim2021
    Diagnosis of COVID-19 and non-COVID-19 patients by classifying only a single cough sound

    Melek, Mesut

    In the last month of 2019, a new virus emerged in China, spreading rapidly and affecting the whole world. This virus, which is called corona, is the most contagious type of virus that humanity has ever encountered. The virus has caused a huge crisis worldwide as it leads to severe infections and eventually death in humans. On March 11, 2020, it was announced by the World Health Organization that a COVID-19 outbreak has occurred. Computer-aided digital technologies, which eliminate many problems and provide convenience in people's lives, did not leave humanity alone in this regard and rushed to provide a solution for this unfortunate event. One of the important aspects in which computer-aided digital technologies can be effective is the diagnosis of the disease. Reverse transcription-polymerase chain reaction (RT-PCR), which is a standard and precise technique for diagnosing the disease, is an expensive and time-consuming method. Moreover, its availability is not the same all over the world. For this reason, it can be very attractive and important to distinguish the COVID-19 disease from a cold or flu through a cough sound analysis via smartphones which have entered into the lives of many people in recent years. In this study, we proposed a machine learning-based system to distinguish patients with COVID-19 from non-COVID-19 patients by analyzing only a single cough sound. Two different data sets were used, one accessible for the public and the other available on request. After combining the data sets, the features were obtained from the cough sounds using the mel-frequency cepstral coefficients (MFCCs) method, and then, they were classified with seven different machine learning classifiers. To determine the optimum values of hyperparameters for MFCCs and classifiers, the leave-one-out cross-validation (LOO-CV) strategy was implemented. Based on the results, the k-nearest neighbors classifier based on the Euclidean distance (kNN Euclidean) with the accuracy rate, sensitivity of COVID-19, sensitivity of non-COVID-19, F-measure, and area under the ROC curve (AUC) of 0.9833, 1.0000, 0.9720, 0.9799, and 0.9860, respectively, is more successful than other classifiers. Finally, the best and most effective features were determined for each classifier using the sequential forward selection (SFS) method. According to the results, the proposed system is excellent compared with similar studies in the literature and can be easily used in smartphones and facilitate the diagnosis of COVID-19 patients. In addition, since the used data set includes reflex and unconscious coughs, the results showed that conscious or unconscious coughing has no effect on the diagnosis of COVID-19 patients based on the cough sound.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    İncele
  • MakaleYalnız künye2021
    Sodium silicate effect on setting properties, strength behavior and microstructure of cemented coal fly ash backfill

    Cavusoglu, Ibrahim; Yilmaz, Erol; Yilmaz, Ali Osman

    Representing an engineered mixture of coal fly ash, cement and water, cemented coal fly ash backfill (CCB) is typically employed for filling the openings created after coal excavation in the earth. A high rate of productivity for coal mines requires a high early-age strength backfill design. Therefore, the use of admixtures in CCB is key for accelerating the backfill setting time and augmenting short-and long-term strength. This study offers the effect of sodium silicate (SS) as an accelerator on early age mechanical and microstructure properties of CCB. SS-based admixture was used for a dosage of 0.5, 1 and 1.5 wt% in CCB that contains 25 wt% ordinary Portland cement OPC and 75 wt% coal fly ash. Backfill setting time was done by using the Vicat system while its strength and pore structure were measured by using the uniaxial compressive strength test, and scanning electron microscopy and Hg intrusion porosimetry. Results display that use of SS in CCB increases its short-term strength gain up to 14% and shortens the mining cycle by cutting its setting time up to 58%. The microstructure analyses also indicate that CCB formulated with SS has a finer pore structure than that without admixture. The outcomes of the present study will be advantageous to evaluate both setting time and strength behavior of CCB used in coal mines, thereby causing the effective backfill plan in terms of money saving and easy operation.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    İncele
  • MakaleAçık Erişim2021
    A Two-Phase Approach using Mask R-CNN and 3D U-Net for High-Accuracy Automatic Segmentation of Pancreas in CT Imaging

    Dogan, Ramazan Ozgur; Dogan, Hulya; Bayrak, Coskun; Kayikcioglu, Temel

    Background and objective: The size, shape, and position of the pancreas are affected by the patient characteristics such as age, sex, adiposity. Owing to more complex anatomical structures (size, shape, and position) of the pancreas, specialists have some difficulties in the analysis of pancreatic diseases (diabetes, pancreatic cancer, pancreatitis). Therefore, the treatment of the disease requires enormous time and depends on the experience of specialists. In order to decrease the rate of pancreatic disease deaths and to assist the specialist in the analysis of pancreatic diseases, automatic pancreas segmentation techniques have been actively developed in the research article for many years. Methods: Although the rapid growth of deep learning and proving satisfactory performance in many medical image processing and computer vision applications, the maximum Dice Similarity Coefficients (DSC) value of these techniques related to automatic pancreas segmentation is only around 85% due to complex structure of the pancreas and other factors. Contrary to previous techniques which are required significantly higher computational power and memory, this paper suggests a novel two-phase approach for high-accuracy automatic pancreas segmentation in computed tomography (CT) imaging. The proposed approach consists of two phases; (1) Pancreas Localization, where the rough pancreas position is detected on the 2D CT slice by adopting Mask R-CNN model, (2) Pancreas Segmentation, where the segmented pancreas region is produced by refining the candidate pancreas region with 3D U-Net on the 2D sub-CT slices generated in the first phase. Both qualitative and quantitative assessments of the proposed approach are performed on the NIH data set. Results: In order to evaluate the achievement of the recommended approach, a total of 16 different automatic pancreas segmentation techniques reported in the literature are compared by utilizing performance assessment procedures which are Dice Similarity Coefficient (DSC), Jaccard Index (JI), Precision (PRE), Recall (REC), Pixel Accuracy (ACC), Specificity (SPE), Receiver Operating Characteristics (ROC) and Area under ROC curve (AUC). The average values of DSC, JI, REC and ACC are computed as 86.15%, 75.93%, 86.27%, 86.27% and 99.95% respectively, which are the best values among well-established studies for automatic pancreas segmentation. Conclusion: It is demonstrated with qualitative and quantitative results that our suggested two-phase approach creates more favorable results than other existing approaches.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    İncele
  • Kitap BölümüYalnız künye2021
    Integrated Reporting and Combined Assurance: A Qualitative Research on the Awareness in Turkey*

    Selimoglu, Seval Kardes; Yesilcelebi, Gul

    Purpose: The aim of this study is to reveal the opinions of the auditors, academicians, and institutions that published integrated reports regarding the development and execution of the assurance process of integrated reports. Design/methodology/approach: For this purpose, interviews were conducted using qualitative research technique to determine awareness about integrated reporting and combined assurance. Within the scope of the research, semi-structured interviews were conducted with six auditors, five academicians, and five workers in institutions that published integrated reports. Qualitative data analysis method was used to analyze the data. Findings: As a result of the research, combined assurance process criteria were proposed in the integrated reports which in line with the opinions of the participants. Originality/value: Institutions around the world are increasingly publishing integrated reports. However, when institutions publish integrated reports, there is no clear standard or any guidance on how to ensure the reliability of these reports. It is seen that AA1000, ISAE3000, GRI Standards, and some local standards are used to provide assurance. At this point, the combined assurance model can be used for the reliability of the information in the integrated reports. Integrated reporting and combined assurance are still relatively new concepts in Turkey. Furthermore, this study is important in terms of the lack of studies on how to provide combined assurance for integrated report when scanned related literature in Turkey. Although readily integrated reporting continued in Turkey, it continues to be an area of application is still under development. In particular, the research reflects the level of integrated reporting awareness and how to ensure assurance of these reports.

    İncele
  • MakaleYalnız künye2021
    A reduced variance unsupervised ensemble learning algorithm based on modern portfolio theory

    Ünlü, Ramazan; Xanthopoulos, Petros

    Unsupervised ensemble learning or consensus clustering has gained popularity due to its ability to combine multiple clustering solutions into a single solution that is robust and often performs better than the individual ones. There have been several approaches to consensus clustering including voting and weighted voting algorithmic schemes. Although there have been several algorithms for adjusting the weights of a consensus clustering all of them are tuned based on some performance characteristic associated with clustering accuracy. In this paper, we propose a method for incorporating weights by taking into consideration the intra algorithmic variability i.e. algorithms that provide solutions with very different performance upon multiple runs. The methodology is inspired by modern portfolio theory and more specifically from Markowitz model for asset allocation where one is trying to identify the most efficient portfolio through the solution of a convex optimization problem. Here, efficiency is defined as the minimum amount of risk for an expected return. We apply this method to different datasets and compare with respect to performance and robustness. The proposed scheme appears to achieve competitive average performance with very low variability.

    İncele
  • MakaleAçık Erişim2021
    Quadrotor Flight System Design using Collective and Differential Morphing with SPSA and ANN

    Kose, Oguz; Oktay, Tugrul

    Quadrotor modeling has been done with collective and differential morphing. Quadrotor initial state and morphing states are drawn in the Solidworks program. Newton-Euler approximation was used for quadrotor modeling. The mass and moment of inertia values required for modeling and simulation were obtained from the Solidworks program. Matlab / Simulink environment and state-space model approaches are used for simulations. A simultaneous perturbation stochastic approximation (SPSA) algorithm was used to determine the quadrotor morphing rates. If the morphing state obtained by SPSA is not included in the values obtained from the drawings, here it is provided to find the moments of inertia with the method based on learning by using the data obtained with the Artificial Neural Network(ANN). Proportional Integral Derivative (PID) is used as the quadrotor control algorithm. PID coefficients are also determined by SPSA.

    İncele
  • MakaleYalnız künye2021
    The Relationship between Body Mass Index and Eating Disorder Risk and Intuitive Eating among Young Adults

    Yılmaz, Hacı Ömer; Zemzemoglu, Tuba Eda Arpa

    Background: Obesity is a serious health problem that threatens public health. There are limited researches exploring the relationship between obesity and eating disorder risk and intuitive eating. The purpose of this study was to determine the rate of eating disorder risk and obesity, and identify the relationship between body mass index (BMI) and eating disorder risk and intuitive eating among young adults. Methods: This cross-sectional study enrolled 1216 young adults. The data were obtained through a questionnaire consisted of three sections of socio-demographic information in the first part, Intuitive Eating Scale-2 (IES-2) in second part and Eating Attitudes Test-26 (EAT-26) in third part. Weight, height, and BMI of participants were also measured by researchers. Results: The overall overweight/obesity rate of the participants was 16% (male=25.9%; female=10.9%). The rate of eating disorders risk was 24.3% in general (male=21.5%; female=25.4%). Overweight/obese had higher eating disorders risk than normal and underweight (26.7%, 23.8%, 21.6%, respectively). IES-2 score of underweight was significantly higher than overweight/obese (3.33±0.35, 3.20±0.37, respectively). Conclusion: This is the first study to examine the relationship between BMI and EAT-26 subscale showing that BMI was positively correlated with EAT-26 and negatively was correlated with IES-2 score. Therefore, BMI may be affected by eating behaviors and intuitive eating. Also, intuitive eating can be a new method of eating, and weight control and management.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    İncele
  • Kitap BölümüYalnız künye2021
    Pandemic transaction cost and impact on the economy

    Çiçen, Yildirim Beyazit

    İncele
  • MakaleYalnız künye2021
    A rapid method to detect green pea and peanut adulteration in pistachio by using portable FT-MIR and FT-NIR spectroscopy combined with chemometrics

    Aykas, Didem Peren; Menevseoglu, Ahmed

    In this research, the determination of green pea and peanut adulteration in pistachio by portable Fourier transform mid-infrared (FT-MIR) and Fourier transform near-infrared (FT-NIR) spectroscopy was studied. A rapid method to detect adulteration in pistachio is a necessity in the food industry because of its high commodity value and being one of the most consumed tree nuts. Pistachio nut is a target for economically motivated adulteration, and green pea, spinach, and peanut are the most seen adulterants in pistachio. Portable FT-MIR and FT-NIR spectrometers are simple, non-invasive, rapid, easy to transport, and cheaper alternatives to traditional methods, including chromatography (GC, HPLC), mass-spectroscopy (GC-MS, LC-MS) for the detection of pistachio adulteration. Powdered pistachio samples were adulterated with powdered green pea and peanut samples at different concentrations (5–40%). Spectra were collected with a portable FT-MIR and FT-NIR spectrometers and analyzed by Soft Independent Modeling of Class Analogy (SIMCA) to generate a classification model to authenticate pure pistachio, and Partial Least Square Regression (PLSR) to predict the levels of adulterants in pistachio. SIMCA provided, in both units, very distinct clusters for pure and adulterated samples with inter-class distance (ICD) over 3. Both units also showed superior performance in predicting adulterant levels with rVal>0.99, standard error of prediction (SEP) < 2.5%. Based on SIMCA and PLSR models, portable FT-NIR spectrometer provided more advantages over portable FT-MIR unit because the prediction with the FT-NIR spectrometer was more precise than the FT-MIR unit. Both portable FT-MIR and FT-NIR units can be used as alternative methods to traditional methods and showed great potential for real-time surveillance to detect green pea and peanut adulteration in pistachio.

    • SDG 2 · Açlığa Son
    İncele
  • Kitap BölümüAçık Erişim2021
    Investigation of the foreign direct investment and environmental pollution nexus for developing countries

    Çelik, Orkun; Korkmaz, Özge; Adalı, Zafer

    In theory, the foreign direct investment and environmental pollution nexus is explained by three hypotheses. Firstly, pollution haven hypothesis assumes that there is a positive nexus between these variables. Secondly, pollution halo hypothesis supposes that there is negative connection between these variables. Lastly, neutrality hypothesis asserts the non-existence of the connection between these variables. In recent years, many researchers have frequently tested whether these hypotheses are valid for different countries. In this study, applying Westerlund panel cointegration test, the authors aim to explore the nexus between foreign direct investment and environmental pollution for 23 developing countries after global crisis. For this aim, they use annual data covering the period 2009-2019. According to the obtained empirical findings, the presence of the long-term nexus between foreign direct investment and environmental pollution is not detected for 23 developing countries. Accordingly, the authors can say that there is neutrality hypothesis.

    • SDG 9 · Sanayi, Yenilikçilik ve Altyapı
    İncele
  • MakaleYalnız künye2021
    Determining the phenolic components by using HPLC and biological activity of Centaurea triumfetti

    Acet, Tuba

    Centaurea species belonging to Asteraceae family are traditionally used herbs in treating many diseases in Anatolia. In the present study, I aimed to determine the biological activities and phenolic contents of the extracts of the aerial parts of Centaurea triumfetti collected from areas with extreme climatic conditions. The determination of antioxidant activity was performed using in vitro assays such as ABTS (2,2-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) and DPPH (1,1-diphenyl-2-picrylhydrazyl). Disc diffusion and microdilution methods were used for determine of antimicrobial activity. Besides that, the diabetes-related inhibition activities of enzymes such as alpha-glucosidase and alpha-amylase were determined using colorimetric methods. The phenolic components of the extracts were analysed by using HPLC. The biological activity of ethyl acetate extracts of the stem was found to be higher those than that of other extracts. This extract was also found to have high antimicrobial and enzyme inhibition activity. Moreover, the major component of the extract was found to be chlorogenic acid. In conclusion, these results suggest that C. triumfetti has the potential for pharmaceutical usage.

    • SDG 3 · Sağlık ve Kaliteli Yaşam
    İncele
  • MakaleYalnız künye2021
    Additivity effect on properties of cemented coal fly ash backfill containing water-reducing admixtures

    Cavusoglu, Ibrahim; Yilmaz, Erol; Yilmaz, Ali Osman

    Cemented coal fly ash backfill (CCB), a flowable structure of coal fly ash, binding agent and mixing water, has been often employed in mining operations to offer ground support as well as waste disposal solutions. An appropriate CCB mass should have sufficient rheological (e.g., workability) and mechanical (e.g., strength and stability) characteristics. Chemical admixtures are well known to greatly enhance the pumpability and strength properties of cementitious materials. Thus, this work provides the effect of water-reducing admixtures (namely, Sikament MR 50 W and Sikament FFN) on characteristics of CCB materials manufactured at a constant slump value. The role of admixtures in CCB mix is to reduce the cement-related costs, to modify the properties of the hardened backfills, and to ensure the quality of the backfill during mixing, transporting, placing, and curing. These admixtures were used at a dosage of 1% and 2% by weight of anhydrous material on cement. Several laboratory tests including slump, setting time, uniaxial compressive strength, scanning electron microscopy and mercury intrusion porosimetry were undertaken on CCB samples to understand their fresh and hardened performance. Experimental results show that the admixtures used ensure the slump required to deliver CCB at low water/cement ratios, improve short- and long-term backfill strengths up to 33%, and decrease the total porosity of the tested CCB. The findings of this study also show that the admixture use in CCB leads to a significant decrease in the considered cement content and a remarkable increase in the mechanical strength. As a result, understanding the actual fresh and hardened properties of CCB remains crucial for the choice of the greatest acting backfill admixture and for a fruitful change from capable experimental results to the in-situ conditions.

    • SDG 12 · Sorumlu Üretim ve Tüketim
    İncele
  • MakaleAçık Erişim2021
    Fuzzy inverse logic: part-2. validation and evaluation of the method; [Bulanık ters mantık: kısım-2. yöntemin doğrulanması ve değerlendirilmesi]

    Öztekin, Ertekin

    In the first part of this study, which consists of two parts, the introduction of the fuzzy inverse logic method, its foundations, computation and process flow and details were given. In this second part, the method was applied on a very simple mathematical problem and on a simple civil engineering design problem in order to investigate and evaluate the validity of the method easily. Fuzzy inverse logic computations have been carried out on these two simple problems for different dimension, sensitivity and acceptable error values. By comparing the obtained results with the desired outputs and mathematical results, the effective computation ability of the method was tried to be revealed. As a result, it is understood that the method developed in this study has many promising aspects in terms of theoretical computations and practical applications and can be used effectively in many scientific fields.

    İncele