Sürdürülebilir Kalkınma Amaçları

Yazarlar

  • MakaleAçık Erişim2025Scopus SJRQ3
    A study on copolymers of styrene with a methacrylamide containing benzofuran side group: Their monomer reactivity ratios, thermal stabilities, thermal degradation kinetics

    Barim, Esra; Demir, Pınar; Değirmenci, Mustafa; Kirilmiş, Cumhur

    The aim of this study was to determine the monomer reactivity ratios, thermal properties and thermal degradation behavior of new P(N-[2-(4-brombenzoyl)-benzofuran-3-yl]-2-methac-rylamide-co-styrene) polymers synthesized at different compositions. For this purpose, novel copolymers of N-[2-(4-brombenzoyl)-benzofuran-3-yl]-2-methacrylamide (NBBM) monomer with styrene (St) monomer were prepared using free radical polymerization method. The 1 H-NMR spectra was used to calculate the compositions of the copolymers. The reactivity ratios of monomers were calculated in line with the universal copolymerization equation using Kelen-Tüdös and Finemann-Ross linearization methods, and found to be r1:0,62 r2:1,09 and r1:0,61, r2:1,07 respectively (where r1 is reactivity ratio of NBBM). DSC, TGA and DTG were used to study the thermal behaviors of the copolymers. The Tg value of P(NBMM) was found to be 211oC and the Tg values of the studied copolymers were determined to increase from 144oC to 184oC with increasing concentration of NBMM units. Thermal data showed that the maximum degradation temperatures increased from 349oC to 391oC as the St units increased in the copolymer system. The activation energy (Ea) values of P(NBBM) and the studied copolymer were determined from the TGA curves obtained at different heating rates and the Flynn-Wall-Qzawa, Kissinger, Tang isoconversional methods were used. Solid state reaction mechanisms were also calculated by being used the Van Krevelen method, a non-isoconversion model. The Ea values obtained with isoconversion models for P(NBBM) and copolymer were found very close to the values obtained from non-isoconversion models. Moreover, the R3 mechanism was proposed for the homopolymer and copolymer.

  • MakaleAçık Erişim2023Scopus SJRQ3
    Investigation of issues affecting thermal comfort in water system underfloor heating applications of buildings with Bayesian networks

    Erkol, Samet; Yücesan, Melih; Gül, Muhammet; Güneri, Ali Fuat

    Thermal comfort is related to the stability of the ambient temperature. Constant changes in ambient temperature appear as a situation that negatively affects comfort. The selected building systems must be arranged to maintain this stability for the continuity of thermal comfort. In this study, issues affecting thermal comfort in water system underfloor heating applications of buildings are handled and analyzed using the Bayesian Network modeling methodology. Visual examples of the problems encountered in field applications are also given. Three different scenarios are tested with the constructed Bayesian Network model. In the first scenario, assumed that mechanical project failures were prevented. In this case, it was observed that the failure rate decreased by about 5%. In the second scenario, assumed that mechanical application failures are prevented along with mechanical project failures. The failure rate decreased by 11% compared to the first situation. The third scenario assumed that the mechanical project preparation phase was concluded without any problems, the mechanical project was implemented without any failures, and the mechanical system was commissioned without any problems. In the last scenario, the failure rate decreased by 14% compared to the first case, and the probability of not providing thermal comfort remained at 2%. As a result of these three scenarios, the possibility of not providing thermal comfort in the underfloor heating system is detailed and interpreted.

  • MakaleAçık Erişim2022
    Characterization and dye adsorption effectiveness of activated carbon synthesized from olive pomace

    Deniz, Fatma; Başgöz, Öyküm; Güler, Ömer; Mazmanci, Mehmet Ali

    Studies, about products obtained from agricultural wastes, have increased within the scope of zero waste studies. The olive pomace is produced as a result of olive oil production. In the present study, activated carbon was synthesized using the olive pomace taken from the olive pomace processing plant operating with a three-phase process. The synthesized activated carbon characterization was performed using Scanning Electron Microscope (SEM), Fourier-Transform Infrared Spectroscopy (FT-IR), Brunauer – Emmett – Teller (BET), and X-Ray Crystallography (XRD) devices. Olive pomace activated carbon (OPAC) was used for the adsorption of dye from an aqueous solution. The adsorption efficiency of the OPAC was investigated. The initial pH value of dye solution (6–9), the amount of activated carbon (0.5 and 1.0 g/L), and initial dye concentration (600–1200 mg/L) were optimized. Also, adsorption kinetic and isotherm calculations were evaluated. The optimum parameters were found as the original pH value (pH=8) of dye solutions, OPAC amount of 1.0 g/L and the initial concentration of 1000 mg/L. The Langmuir isotherm model and the pseudo-second-order kinetic model were found as the most suitable models. It can be said that the synthesized material can be used at dye removing from wastewater.

    • SDG 6 · Temiz Su ve Sanitasyon
    • SDG 12 · Sorumlu Üretim ve Tüketim
    AtıfScopus6OpenAlex3
    ScopusTR Dizinİncele
  • MakaleAçık Erişim2021Scopus SJRQ3
    A BAYESIAN NETWORK-BASED APPROACH FOR FAILURE ANALYSIS IN WEAPON INDUSTRY

    Yucesan, Melih; Gul, Muhammet; Guneri, Ali Fuat

    Gun and rifle manufacturing contain various failures in the process of CNC machining, material supply, research & development, infrastructure and, operator. Due to these failures, the enterprise is exposed to great economic losses and a decrease in competition in the global market. In addition, failures in production cause events that seriously threaten human health. Failure analysis can increase safety by determining the cause of potential errors and taking measures for identified errors in the life cycle of the products. Therefore, this study employs a Bayesian Network (BN)-based modeling approach for capturing dependency among the basic events and obtaining top event probability. Firstly, a fault tree analysis (FTA) diagram is constructed, since its target is to pinpoint how basic event failures result in a top event (system) failure by an AND/OR logical gate. While, AND logical gate should take place in both cases, it is sufficient to realize one of the states in the OR logical gate. Then, a BN-based on fault tree transformation is applied. A case study in a leading weapon factory that produces various types of guns and rifles in the Black Sea region of Turkey is performed. For the application viewpoint, appropriate control measures can be taken into account to decrease the number of failed products based on the performed failure analysis.

    AtıfScopus6WoS5OpenAlex7
    ScopusWeb of Scienceİncele
  • MakaleYalnız künye2021
    DISSEMINATION OF HEAVY METAL CONTAMINATION IN SURFACE SEDIMENTS OF BATLAMA STREAM, GIRESUN, TURKEY

    Ustaoğlu, Fikret; Kutlu, Banu; Tepe, Yalçın; Aydin, Handan

    The aim of this study is to detect the heavy metal contamination in the sediment of Batlama Stream and to evaluate the anthropogenic effect. Field studies were seasonally carried out in 3 stations between June 2014 and July 2015. In the sampling studies carried out in Batlama Stream, contamination factor (CF), enrichment factor (EF), potential ecological risk factor (Eri), lowest effect level (LEL), geoaccumulation index (Igeo) contamination indicators were used in order to evaluate sediment contamination. In Batlama Stream, average heavy metal level of three stations was detected in mg/dry kg in the sediment as Cr 7.08, Mn 63.62, Fe 858.04, Co 5.47, Ni 4.99, Cu 20.61, Zn 49.60, Cd 0.09, and Pb 20.68. Elements which the sediment has most are Fe, Mn, and Zn. According to EF, Pb was detected as an enriching element. Eri Pb is in the low risk group. In LEL value, the highest Pb average was found as 31. According to Igeo values, Pb is a moderate contaminant. This metal has anthropogenic sources and it is caused by domestic, agricultural, and waste waters. In the elements analysed in Batlama Stream sediment (apart from Pb), it is indicated that it is generally a clean stream and considered reference stream.

    AtıfScopus3
    Scopusİncele
  • MakaleYalnız künye2020
    A RESEARCH FOR BACTERIAL SELF-HEALING IN METAKAOLIN BASED GEOPOLYMER MORTARS

    Yilmazer Polat, Berivan; Uysal, Mucteba; Korkmaz, Volkan

    Cement production is a polluting process for nature. For this reason, new types of concrete which can be produced with recycled materials and without cement continue to be investigated. On the other hand; cracks in structural elements reduce the strength and durability of a building. Extending service life of buildings has eliminated the cost of rebuilding and thus, contributed to both the economy and the ecosystem. Due to this, research on crack healing in Portland cement concretes with various bacteria is continuing for some time. However, there are not enough studies in literature regarding the improvement of metakaolin-based geopolymer mortars produced without using cement by urolytic bacteria. The parameters of temperature, pH and void ratio of bacterial geopolymer mortar affect the viability of bacteria. For example, pH value of the medium required for the survival of bacteria is, generally around nine. During the production of geopolymer concrete, a sudden increase in high alkali environment occurs due to use of activators. This reduces the survival rate of bacteria added to the mixture during the production of geopolymer mortar. In this study, the most suitable environment for geopolymer mortar, and the conditions for the bacteria to survive until the end of the curing process for the mortar to be strengthened were investigated. Analyses on the effects of urolytic bacteria and geopolymer mortar healing process on mechanical strength of the mortar were conducted. Sporosarcina Pasteurii were used for the self healing process. Various mixtures of geopolymer mortars were cured under different environmental conditions to observe changes in their mechanical strength and water absorption capacity. As the result of the study, the most suitable mixture ratio and curing medium were identified. It was observed that the nutrient, ensuring the life cycle of the urolytic bacteria, had no negative effect on the mechanical strength of mortar and reduced capillary water absorption of the mortar. This study is a specific text in the literature that analyzes bacterial curing conditions and the effect of improving geopolymer mortar.

    AtıfScopus14
    Scopusİncele
  • Dergi
    Environmental Research and Technology
  • Dergi
    Journal of Thermal Engineering
  • Dergi
    Sigma Journal of Engineering and Natural Sciences