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    Application fuzzy DEMATEL methodology to investigate some technical parameters of biochemical methane potential (BMP) test produced vegetable waste anaerobic biogas
    (Springer, 2022) Bashan, Veysi; Cetinkaya, Afsin Y.
    As the transition to renewable energy systems is accelerating, anaerobic digestion, which is one of the methods of energy recovery from organic substrates, continues to be studied with great interest by scientists. Anaerobic digestion research and applications are mostly carried out with biochemical methane potential (BMP) tests to decide the methane potency of sewage sludge, energy crops, and organic wastes. Unlike long and costly continually reactor experiments, actually, BMP tests are cumulative and can be performed with a relatively low investment of materials, technical labor, and also time. For the BMP to give accurate results, the effect of all the tools and technical parameters used in the implementation of the BMP should be well understood. In such situations, it is very useful to apply fuzzy logic methods in multi-criteria decision-making stages when more than one parameter changes at the same time. Therefore, in this study, fifteen parameters were determined and analyzed with the fuzzy DEMATEL (decision-making trial and evaluation laboratory) method to understand the cause-effect mechanism of the technical parameters of BMP. As a result of these analyses, it was seen that the material of the reactor (r(i)-c(j) value of 0.55), the particle size (r(i)-c(j) value of 0.43), the effect of mixing (r(i)-c(j) value of 0.32), and the amount of the total solids (TSA) value of 0.25) had a high effect in the causal sense. It was observed that the first-order parameter (material of reactor) was 27% stronger than the second-order (the particle size) parameter in terms of causality. Likewise, the second-order parameter is 34% stronger than the third-order parameter (the effect of mixing) in terms of cause effect. In addition, it was understood that the most effective parameters in the mechanism of effect were pH (r(i) +c(j) value of 3.41), C/N ratio (r(i)-c(j) value of 3.26), and temperature (r(i)-c(j) value of 3.07), respectively. Besides, high methane yield is seen in mesophilic conditions. The average cumulative biogas yield of the reactor is 282.1 NmL/g VS. The highest percentage of methane formed in the biogas occurred on the 21st day. Briefly, this study is important to provide a facilitating way for researchers working on BMP to understand the causeeffect mechanism of system technical requirements.
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    Influential Publications and Bibliometric Approach to Heavy Metal Removals for Water
    (Springer Int Publ Ag, 2022) Bashan, Veysi; Cetinkaya, Afsin Y.
    Heavy metals are elements that can have toxic effects even at low concentrations. Heavy metal pollution is one of the most concerning issues at the global level because of the health risks it causes and its negative effects on the ecosystem. Many studies have been carried out in the past years to reduce heavy metal emissions, pollution, and their effects on health. In this context, a scientometric study was conducted to show how this topic has developed academically and to identify effective studies in the field of heavy metal removals for water. When the Web of Science (WoS) database is searched, a total of 22,911 articles were collected based on the heavy metal removals for water subjects, and then, articles were sorted and the top 100 most cited articles were determined. By determining the top 100 most cited articles on this subject, bibliometric analysis has been carried out by covering co-occurrence, co-citation analysis, cluster analysis, and much more. When these top 100 most cited articles were examined, it was seen that review articles were in the majority (59%), and there were more studies in environmental sciences, engineering environmental, engineering chemical, biotechnology applied microbiology categories. It has been observed that most of these most cited articles were published between 2007 and 2012, and the citations given to these 100 articles increased almost linearly since 2007. In addition, it has been determined that China ranks first in this regard with 23 articles and 21,137 citations. The working network between countries, institutes/universities has been revealed. It was determined that the words adsorption, heavy metals, and waste were used the most among the keywords. This study is expected to lay the groundwork for future discussions on the subject. Our analysis provides information on technology and informs decision-makers and researchers about the value of new and existing technologies and future opportunities.