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    Effects of microencapsulated phase change material on physico-mechanical and thermoregulation performance of lightweight geopolymer concrete with zeolite and perlite
    (Elsevier, 2025) Oren, Osman Hulusi; Mandev, Emre; Kaya, Mehmet; Sari, Ahmet; Hekimoglu, Gokhan; Cikman, Ismail Umit; Subasi, Serkan
    This study examines impact of microencapsulated phase change material (MPCM) additives on physical and mechanical characteristics of geopolymers produced using natural zeolite and slaked lime. The binder composition consists of 90 % zeolite and 10 % slaked lime, activated with NaOH at a Na/binder ratio of 14 % by weight. Basalt-based sand and perlite were used as aggregates with a water/binder ratio of 0.60. MPCM was added in varying proportions of 8 %, 16 %, and 24 % relative to the binder weight. Samples were molded in dimensions of 50 x 50 x 50 mm and 200 x 200 x 20 mm, then cured at 95 degrees C for 24 h. Differential Scanning Calorimetry (DSC) outcomes presented that geopolymer composite with MPCM has a melting degree of 26.45 degrees C and a melting enthalpy of 17.8 J/g. Fourier Transform Infrared Spectroscopy (FTIR) results confirmed physical integration of MPCM into geopolymer structure. The study also evaluated compressive strength, ultrasound pulse velocity (UPV), dry unit weight, and microstructural properties using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS). Thermoregulation performance experiments demonstrated that the MPCMenhanced samples effectively moderated temperature fluctuations, maintaining lower temperatures for controlled heating and higher temperatures for natural cooling phases compared to the control sample. Thermal regulation capabilities of MPCM-infused geopolymers were evidenced by their property of absorbing and releasing heat, which is critical for energy-efficient building materials. Additionally, the durability and stability of the geopolymer matrix were enhanced by the uniform dispersion of MPCMs, which also improved the composite's mechanical performance. The successful integration of MPCMs highlights their potential in developing sustainable construction materials that contribute to energy savings and environmental conservation.
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    Sudden Death Due To Rupture Of Dissection Of The Aorta: Three Cases
    (Düzce Üniversitesi, 2010) Din, Hasan; Özbek, Ali; Kaya, Mehmet; Yağmur, Fatih
    Acute aorta dissection is an urgent condition that presented with chest pain, back or abdominalpain and usually resulted with death. We presented three autopsy performed cases thatdetermined cardiac tamponade developed secondary to aortic dissection. Three of them weremale and their ages were 36, 49 and 62 years. Death was occurred after back and epigastric painin two patients while other patient was found dead in home. All of them did not have any diseasein history. Death rates could be reduced under to %50 with intervention on time so the possibilityof aorta dissection must not be forgotten in cases with abdomen, thorax or back pain onadmission