Toward halogen-free flame resistant polyethylene extrusion coated paper facings

Wire and cable coverings are potentially a major cause of fire in buildings and other installations. As they need to breach fire walls and are frequently located in vertical ducting, they have significant potential to increase the fire hazard. It is therefore important to understand the ignition and burning characteristics of cables by developing a model capable of predicting their burning behaviour for a range of scenarios. The fire performance of electrical cables is usually dominated by the fire performance of the sheathing materials. The complexity of the problem increases when cable sheathing incorporates fire retardants. One-dimensional pyrolysis models have been constructed for cable sheathing materials, based on milligram-scale and bench-scale test data by comparing the performance of three different software tools (ThermaKin, Comsol Multiphysics and FDS, version 6.0.1). Thermogravimetric analysis and differential scanning calorimetry were conducted on powdered cable coatings to determine the thermal degradation mechanism, the enthalpy of decomposition reactions, and the heat capacities of all apparent species. The emissivity and the in-depth absorption coefficient were determined using reflectance and transmittance measurements, with dispersive and non-dispersive spectrometers and integrating spheres. Bench-scale tests were conducted with a mass loss calorimeter flushed with nitrogen on samples in a horizontal orientation, for comparison with the pyrolysis model of non-flaming decomposition at an external heat flux of 50 kW m-2. The parameters determined through analysis of the milligram-scale data were used to construct a pyrolysis model that predicted the total mass loss from calorimeter tests in anaerobic conditions. A condensed phase pyrolysis model that accurately predicts in-depth temperature profiles of a solid fuel, and the mass flux of volatiles evolved during degradation of the fuel, is an essential component of a comprehensive fire model, which when coupled to a computational fluid dynamics code can be used to predict the burning processes in a fire scenario. Pyrolysis models vary considerably in complexity based on the assumptions incorporated into the development of the model

KARAKTERISTIK DAN PROSES PELAPUKAN PADA BATUAN PENYUSUN CANDI ABANG, KECAMATAN BERBAH, KABUPATEN SLEMAN, PROVINSI DAERAH ISTIMEWA YOGYAKARTA

Candi Abang merupakan salah satu peninggalan Hindu yang masih bertahan hingga sekarang. Berlokasidi Dusun Sentonorejo, Desa Jogotirto, Kecamatan Berbah, Sleman, Daerah Istimewa Yogyakarta, candi inidiperkirakandibangun sekitar abad ke-9 dan ke-10 pada zaman Kerajaan Mataram Kuno. Beberapa pendapat mengatakan bahwa candi ini diperkirakan mempunyai umur lebih muda dari candi-candi Hindu lainnya.Berbeda dengan candi-candi di Yogyakarta yang umumnya tersusun oleh batuan andesit berwarna hitam-abu-abu, Candi Abang tersusun oleh batuan beku yang permukaannya berubah menjadi merah.Oleh karena itu, penelitian karakteristik batuan penyusun Candi Abang perlu dilakukan untuk mengetahui asal-usul batuannya. Analisis petrografi dan XRD (XRay Diffraction) yang dilakukandalam penelitian ini digunakan untuk mengetahui tekstur dan mineralmineral penyusun batuan.Secara megaskopis batuan penyusun candi berupa andesit dengan struktur skoriadisusun oleh mineral plagioklas, piroksen, hornblende, dimana warna hitam semakin inensif bergradasi menjadi merah menuju permukaan batuan akibat proses pelapukan. Proses pelapukan terjadi akibat adanya lubang-lubang gas pada batuansehingga air hujan akan masuk dan melarutkan mineral penyusun batuan. Berdasarkan pengamatan petrografi, andesit penyusun Candi Abang bertekstur porfiroafanitik hipokristalin dengankomposisi mineral terdiri dariplagioklas, piroksen, hornblende, biotit dan mineral opak sebagaifenokris, sedangkan massa dasarnya berupa gelas vulkanik. Indikasi pelapukan diketahui dari analisis petrografi yang memperlihatkan besarnya persentase pori, adanya plagioklas yang mengalami perubahan bentuk dan batas mineral yang buruk. Analisis XRD bulk pada sampel batuan memperlihatkan penyusun yang dominan adalah plagioklas, biotit, piroksen, hornblende yang mengindikasikan batuan bersifat intermediet-basa. Hasil analisis XRD clayoriented pada batuan berwarna merah menunjukkan hadirnya mineral lempung jenis smektit, klorit dan kaolinit. Kata Kunci : Candi Abang,pelapukan, petrografi, xr