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PENERAPAN MODEL PROBLEM BASED LEARNING (PBL) PADA KONSEP USAHA DAN ENERGI UNTUK MENINGKATKAN KETERAMPILAN BERPIKIR KRITIS DAN BERPIKIR KREATIF SISWA SMA Siska Sucirahayu; Abdul Halim; Nasrullah Idris
Jurnal Pendidikan Sains Indonesia Vol 3, No 1 (2015): April 2015
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (109.565 KB)

Abstract

Penelitian ini bertujuan untuk mengetahui aktifitas guru, meningkatkan keterampilan berpikir kritis dan berpikir kreatif siswa setelah diterapkan model PBL, mengetahui tanggapan siswa. Penelitian ini menggunakan metode pre-eksperimental dan one-group pretest-posttest design.Sampel penelitian diambil secara acak dari seluruh siswa kelas XI sebanyak 25 orang dari satu kelas. Pengumpulan data menggunakan instrumen keterampilan berpikir kritis dan berpikir kreatif,  pedoman observasi, angket siswa. Hasil penelitian menunjukkan bahwa aktifitas guru pada saat diterapkan model PBL menunjukkan kategori baik dan sangat baik, penerapan PBL mampu meningkatkan keterampilan berpikir kritis dan kreatif dengan kategori sedang, hampir seluruh siswa memberikan tanggapan positif atau setuju dengan penerapan PBL pada konsep usaha dan energi.
PREPARATION OF INORGANIC CATALYST BASED HEMATITE (a-Fe2O3) COMPOUND EXTRACTED FROM ACEH IRON ORE MINERAL AND ITS CATALYTIC ACTIVITY ON TRANSESTERIFICATION OF COCONUT OIL Muliadi Ramli; Anneza Astriet; T. Banta Darmawan; Saiful Saiful; Susilawati Susilawati; Nasrullah Idris
Jurnal Natural Volume 19, Number 1, February 2019
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24815/jn.v19i1.12855

Abstract

Hematite (Fe2O3) was successfully extracted from the Aceh iron ore mineral by precipitation method with employing sulphuricacid (H2SO4) as chemical agent.  Furthermore, the extracted hematite was modified with sodium metal (K), namely it doped with NaOH of 5% and 10% (w/w), respectively. Based on the characterization results using XRD and SEM- EDS proved that modified catalyst (Na2O/Fe2O3) with their homogeneous size were resulted while the hematite (Fe2O3) particles was dopped withNaOH at its low concentration of (5% wt/wt), however while doping with the higher concentration of NaOH (10% w/w), agglomeration was taken place among the catalyst particles in which decreasing the surface area of the modified catalysts. Finally, the modified catalyst (Na2O/Fe2O3) was successfully applied as an inorganic catalyst on transesterification of coconut oil and methanol (T = 55 – 60oC, 2 h)for forming methyl esters asbiodiesel compounds. 
Assessment of Al3+ Ion Selectivity Coefficient (Kij) in Polyurethane Membranes Derived from Castor Oil (Ricinus communis. L) via Separated Solution Method Jannah, Firaihanil; Idroes, Rinaldi; Nazaruddin, Nazaruddin; Idris, Nasrullah; Safitri, Eka; Md Sani, Nor Diyana
Grimsa Journal of Science Engineering and Technology Vol. 1 No. 2 (2023): December 2023
Publisher : Graha Primera Saintifika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.61975/gjset.v1i2.18

Abstract

The influence of foreign ions on the response of Al3+ ISE-based polyurethane membranes from castor oil has been determined using SSM. The results showed that the presence of the foreign ions tested did not affect the sensitivity and response of Al3+ ISE. The influence of foreign ions Na+, K+, Li+, Pb2+, Ca2+, Co2+, Cu2+, Ni2+, Cr3+, and Fe3+ on the selectivity of ion-selective electrodes (Al3+ ISE) in the concentration range 1x10-9 – 1x10-4 M has been performed using separate methods. The results show that the presence of foreign ions does not affect the performance of Al3+ ISE with a Kij value < 1. The selectivity sequence of foreign ions is Fe3+ > Cr3+ > Pb2+ > Cu2+ > Ni2+ > Co2+ > Ca2+ > Li+ > Na+ > K+ respectively.