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Yayın Preface(Springer Science and Business Media Deutschland GmbH, 2021) Dutta, Subashisa; İnan, Esin; Dwivedy, Santosha Kumar[No abstract available]Yayın Development of acoustic and thermal insulation materials from pantyhose waste(Trans Tech Publications Ltd, 2023-03-31) Küçükali Öztürk, Merve; Sezgin, Hande; Yalçın Enis, İpek; Dolu, CemPopulation growth, urbanization, industrialization, developing technology, increasing welfare level and changing consumption habits cause solid wastes to increase day by day. There are also sub-waste groups that have not yet been fully recognized among the solid waste groups in which textile wastes have a large share. One of them is pantyhose, which has been indispensable for modern life since the day it was presented to the consumer. These socks, which are made of polyamide and elastane fibers that are easily punctured, run and become unusable when worn once or several times, are generally thrown away after use. These pantyhose wastes, which are not biodegradable due to their raw materials, also pose an environmental risk. Within the scope of the study, thermal and sound insulation properties of carded and needle-punched pantyhose wastes are investigated. The results show that the thermal and acoustic properties of the developed material are at a sufficient level, and it has ensured that polyamide wastes, which have superior properties among thermoplastic polymers and have high economic value, are brought back into the economy.Yayın Preface(Springer Science and Business Media Deutschland GmbH, 2020) Dutta, Subashisa; İnan, Esin; Dwivedy, Santosha Kumar[No abstract available]Yayın Yayın Evaluation of thermal insulation and air permeability of needle-punched nonwovens recycled from waste pantyhose(Trans Tech Publications Ltd, 2024) Sezgin, Hande; Yalçın Eniş, İpek; Maral, HıdırWaste amount in the textile industry is rising in tandem with rising production and consumption levels. Reusing waste is always the best option, but for some textile products, this isn't the case. A ruptured pair of pantyhose is among the one of the best examples. Due to their delicate structure, these products are easily punctured, so they are disposed of in solid waste sites after 2-3 times use. In this study, it is aimed to recycle these pantyhose waste (polyamide/elastane), and use it in the production of thermal panels, and to statistically examine the effects of varying thickness and elastane content on the thermal insulation and air permeability of this material. In order to create nonwoven structures with varying thicknesses and elastane ratios, the pantyhose wastes converted into fiber form and then into carded web by using a carding machine. Then, a needle punching technology is used for the web formation process. The Minitab software program is used to analyze changes in air permeability and thermal conductivity coefficient between the samples using a full factorial experimental design. The findings indicate that while both factors affected air permeability, only the changing thickness had a statistically significant impact on the thermal conductivity coefficient.Yayın Volatility spillovers and structural breaks across traditional and digital assets: an econometric investigation (2020–2025)(Springer Nature, 2026-04) Özyeşil, Mustafa; Teker, Dilek; Teker, Suat; Tembelo, HavaneThe need to comprehend the linkages of volatility is more pronounced now owing to the rise of different asset classes, both traditional and digital. In this light, this study focuses on examining the volatility spillovers and structural breaks of four selected key financial instruments: S&P 500 Index, NASDAQ Composite Index, Gold Futures, and Bitcoin. Specifically, this research is designed to investigate how volatility is evolving and transmitting in the presence of economic shocks using a high-frequency dataset for the period January 2020 to May 2025. To capture the dynamic dependencies and regime shifts, sophisticated econometric methods such as GARCH models, the Diebold–Yilmaz spillover index, wavelet coherence, and structural break tests were applied. The results exhibit that Bitcoin is characterized by greater conditional volatility relative to traditional assets. In addition, there is strong volatility clustering across all series. Furthermore, strong volatility spillovers, especially from equities to crypto assets, were identified, and several structural breaks align with important macro-financial milestones such as the COVID-19 crisis and inflationary shocks. It’s shown that the interlinkages among financial markets appear to be on the rise, with asset class volatility increasingly transmitted across them freely. The traits exhibited by digital assets such as Bitcoin differ significantly from those of traditional financial instruments, highlighting the need for more sophisticated risk management strategies. This research fills the gap in the literature cross-market volatility with a time-domain, frequency-domain, and structural change approach. These findings are timely for digital finance in relation to portfolio diversification, strategic asset allocation, and instep with new policies on digital assets.
