2 research outputs found
Geri dönü türülmü beton agrega ile üretilen nano silis katk l betonlar n mühendislik özelliklerinin belirlenmesi
No full textGeni bir alanda kullan ma hitap etmesi betonu en çok kullan lan yap malzemelerinden biri yapm t r. Anadolu'da uzun y llardan beri bilinen ve kullan lan betonun kullan m gün geçtikçe zaman içerisinde art göstermi tir. Türkiye Haz r Beton Birli i 2022 verilerine göre ülkemiz 105 milyon m³'ü bulan üretim ile Avrupa'da lider konumundad r. Bu denli üretimin fazla olmas neticesinde sektörde ortaya ç kan at klar n; üretimde tekrar kullan m ekonomik ve çevresel fayda sa lamas aç s ndan önem arz etmektedir. Türkiye'de beton üretim ve in aat at klar miktar dü ünüldü ünde geri dönü üm agregas n n çevresel ve ekonomik çerçevede büyük öneme sahip olmas nedeniyle, önümüzdeki dönemlerde kullan m n n yayg nla abilece i dü ünülmektedir. Bunun yan s ra geli en teknoloji ile en yayg n kullan lan ve en önemli yap malzemelerinden olan betona nano boyutta kullan lan baz maddelerin eklenmesiyle yeni özellikler kazand r labildi i ve bu yolla daha geli mi özelliklerde malzemelerin üretimi gerçekle tirildi i yap lan çal malar sonucu elde edilmi tir. Bu çal ma kapsam nda da yeryüzünde oksijenden sonra bile ikleri halinde en çok bulunan elementlerden olan silisyumdan üretilen nano silis kullan m ile at k betonlar n agrega olarak beton üretiminde kullan m ara t r lm t r. Nano silis katk s ve geri dönü türülmü beton agrega içermeyen referans kar m, %2,5 nano silis ve geri dönü türülmü beton agregas içeri ine sahip üretimi yap lan beton ile %5 nano silis katk l geri dönü türülmü beton agregas kullan larak üretilen beton numuneleri küp kal plara (15×15×15 cm) al nm ve kür havuzunda bekletilmi tir. Üretilen bu beton numuneleri mekanik ve fiziksel testlere tabi tutulmu tur. Bu testlerin yan s ra tane boyutu analizi, XRD, XRF,SEM ve DTA-TG gibi ileri teknolojik deneylerde gerçekle tirilmi tir. Bu çal ma sonucunda elde edilen veriler de erlendirildi inde; katk s z numunelerin fiziksel ve mekanik özelliklerinin daha yüksek ç kt fakat %2.5 ve % 5 oran nda nano silis ve geri dönü türülmü beton agrega içeri ine sahip betonlar nda 28 günlük kür sürelerinde tasarlanan C25/30 beton s n f n sa lad ve yap lan yüksek teknoloji analizlerinden de elde edilen veriler de erlendirildi inde geri dönü türülmü agregan n beton fiziksel ve mekanik özelliklerinde olumsuz yönde ne kadar etki gösterse de kullan lan nano silis ile beton kapanma mekanizmalar n n olu tu u ve durabilite özelliklerinin iyile ti i bu tip üretim yap lan betonlar n özel kullan m alanlar na sahip betonlarda kullan labilece i sonucuna ula lm t r
Individual Differences In The Relationship Between Attachment And Nomophobia Among College Students: The Mediating Role Of Mindfulness
No full textBackground There is a growing interest in nomophobia, which is defined as the fear of being out of cellular phone contact, or "feelings of discomfort or anxiety experienced by individuals when they are unable to use their mobile phones or utilize the affordances these devices provide”. However, only limited research can be found in terms of its determinants at present. Contemporary literature suggests that the relationships among attachment styles, mindfulness, and nomophobia have not been investigated. Objective This study aims to investigate the mediating effect of mindfulness on the relationship between attachment and nomophobia. In addition, the study also focuses on gender differences in attachment, mindfulness, and nomophobia. A theory-based structural model was tested to understand the essentials of the associations between the constructs. Methods The Experiences in Close Relationships Scale, Nomophobia Questionnaire, and Mindful Attention Awareness Scale were used to collect data from undergraduate students (N=450; 70.9% women [319/450]; mean age=21.94 years [SD 3.61]). Two measurement models (ie, attachment and mindfulness) and a structural model were specified, estimated, and evaluated. Results The structural equation model shows that the positive direct effects of avoidant (.13, P=.03) and anxious attachment (.48, P<.001) on nomophobia were significant. The negative direct effects of avoidant (?.18, P=.01) and anxious attachment (?.33, P<.001) on mindfulness were also significant. Moreover, mindfulness has a significant negative effect on nomophobia for women only (?.13, P=.03). Finally, the Sobel test showed that the indirect effects of avoidant and anxious attachment on nomophobia via mindfulness were significant (P<.001). The direct and indirect effects of anxious attachment, avoidant attachment, and mindfulness altogether accounted for 33% of the total variance in nomophobia. Gender comparison results show that there is a significant difference in attachment based on gender (F2,447=6.97, P=.01, Wilk ?=.97, partial ?2=.03). Women (mean 68.46 [SD 16.96]) scored significantly higher than men (mean 63.59 [SD 15.97]) in anxious attachment (F1=7.93, P=.01, partial ?2=.02). Gender differences in mindfulness were not significant (F4,448=3.45, P=.69). On the other hand, results do show significant gender differences in nomophobia (F4,445=2.71, P=.03, Wilk ?=.98, partial ?2=.02) where women scored significantly higher than men. Conclusions In general, individuals who are emotionally more dependent and crave more closeness and attention in the relationship tend to display higher levels of fear or discomfort when they have no access to their mobile phones. However, gender has a differential impact on the relationship between avoidant attachment and nomophobia. This study establishes the impact of mindfulness on nomophobia for women; therefore, future studies should test the effectiveness of mindfulness-based therapy approaches and confirm whether they are effective and efficient. On the basis of significant gender difference in nomophobia and attachment, we conclude that gender should be taken into account in mindfulness-based treatments dealing with nomophobia.PubMedWoSScopu
