Innovations to increase the effective height of storeys in buildings are using a flat slab system. Flat slab system is a slab that is only supported by columns without any supporting beam. By the abstain of beams, designers are able to reduce the storey height and to reduce the structural weight. Other than that, flat slabs offer a more flexible installation of building utilities, simpler reinforcement, and simpler installation of scaffolding and formwork. This study was conducted to analyse the performance of flat slabs when applied to buildings compared with the conventional slabs. The flat slab system is expected to be able to withstand gravity and earthquake loads. The Building of the Faculty of Sport Science, Universitas Negeri Malang, with a total of 7 floors and 1 semi-basement was used as research object. This research was conducted using programme simulation, ETABS and SAP2000. The research was intended to analyse the resulting seismic base shear, the fundamental period, the structural stiffness, the ultimate performance evaluation, and the storey drift if the building designed using flat slab system. Results showed that (1) Building with flat slab system has a lighter weight than the one with conventional slab system. Building weight affects the seismic base shear value of the building. The heavier a building is, the greater the seismic base shear value of a building; (2) The fundamental period analysis resulted the structural vibration time (Tc) in flat slab structure is greater than in the conventional slabs. The heavier the building weight, the structural vibration time (Tc) that occurs will be smaller; (3) The structural stiffness of building using flat slab system is less than in the conventional slabs system; (4) Both of building using flat slab system and conventional slabs meet the requirement of service performance and ultimate performance; and (5) The storey drift in building using flat slab system is larger than in the conventional slabs. This is due to the conventional slab structure has a greater stiffness than flat slab structure.

Abstract. This paper presents the result of studies on utilizing metakaolin obtained from Belitung as fly ash substitute material to produce geopolymer paste. Mechanical properties were assessed by compressive strength while physical properties were assessed by setting time, porosity, microstructure test and density test. The experiment was performed on geopolymer paste with 0, 25%, 50%, 75% and 100% fly ash replacement with metakaolin. Sodium Hidroxide (NaOH) with concentration of 10 Molars and Sodium Silicate (Na2SiO3) were used as alkaline activator. In addition, activator ratio between sodium silicate to sodium hidroxide of 2 was applied. The result obtains that increasing metakaolin contain in mixture deliver longer setting time, higher open pore number, lower density and lower compressive strength of geopolymer paste. However, adding metakaolin up to 25 % into geopolymer paste mixture could increase mechanical and physical properties of geopolymer paste.

Abstraksi            Buah pisang adalah salah satu buah potensial di Desa Galengdowo, yang dapat berbuah sepanjang tahun. Hasil panen pisang mencapai ± 10 ton / tahun. Selama panen massal, terutama mangga, harga pisang turun sehingga petani mengalami kerugian besar. Akibatnya, solusi alternatif diperlukan untuk mengatasi masalah ini, yaitu dengan mengolah pisang menjadi keripik pisang, yang telah diprakarsai oleh beberapa kelompok pengrajin keripik pisang di desa Galengdowo. Masalah yang dihadapi oleh pengrajin adalah kapasitas produksi yang rendah, karena masih menggunakan metode manual, terutama terkait dengan pengeringan minyak dari wajan dan penimbangan keripik pisang. Mayoritas penduduk adalah petani & peternak sapi perah dengan tingkat pendidikan rendah (rata-rata lulusan SMP dan SMA). Dengan penyuluhan dan bantuan 1 unit TTG mesin spinner peniris minyak keripik pisang kapasitas 5 kg dan 1 unit timbangan digital dari tim, para pengrajin akan dapat meningkatkan kapasitas produksinya sehingga manfaat yang diperoleh akan lebih besar, dengan produksi keripik pisang yang enak, kering dan renyah, yang dapat diproduksi terus menerus. Sehingga akan dapat meningkatkan pendapatan pengrajin keripik pisang di Desa Galengdowo.Kata kunci: keripik pisang, mesin spinner, kapasitas produksi

Phalaenopsis sp is one of the types of orchids native to Indonesia with high commercial value, but these orchids are quite difficult to cultivate because the seeds are microscopic and do not have endosperm that need to be cultivated in vitro. In vitro orchid cultivation requires a suitable supporting medium. This study aims to determine the effect of coconut water (Cocos nucifera L) using VW medium on the growth of Phalaenopsis sp protocorm orchid in vitro. Research has been carried out at the DD Orchid Nursery Network Culture Laboratory Dadaprejo Junrejo, Batu, East Java, starting from November to January 2020. This study uses a Completely Randomized Design (CRD) to compare different concentrations of coconut water (Cocos nucifera L) as ie, 0%, 15%, 30%, and 60% treatment. Each concentration was repeated 5 times and each repetition consisted of 5 bottles of Phalaenopsis sp. Protocorm and cultured for 4 weeks. The results showed that the highest number of protochromes and shoots were produced at the same concentration, namely 150 ml / L coconut water treatment (15% concentration) with an average number of 64 protocorms and 14 shoots. Keywords: Coconut water (Cocos nucifera L), Phalaenopsis sp., In vitro, growthABSTRAKPhalaenopsis sp merupakan salah satu jenis anggrek asli Indonesia dengan nilai komersial yang tinggi, tetapi anggrek ini cukup sulit dibudidayakan karena bijinya bersifat mikroskopis dan tidak memiliki endosperm sehingga perlu dibudidayakan secara in vitro. Budidaya anggrek secara in vitro memerlukan medium pendukung yang sesuai. Penelitian ini bertujuan untuk mengetahui pengaruh air kelapa (Cocos nucifera L)  menggunakan medium VW terhadap pertumbuhan protocorm anggrek Phalaenopsis sp secara in vitro. Telah dilakukan penelitian di Laboratorium Kultur Jaringan DD Orchid Nursery Dadaprejo Junrejo Kabupaten Batu Jawa Timur, dimulai dari bulan November sampai dengan bulan Januari 2020. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) untuk membandingkan beberapa konsentrasi air kelapa (Cocos nucifera L) yang berbeda  sebagai perlakuan yaitu, 0 %, 15%, 30%, dan 60 %. Masing-masing konsentrasi dilakukan 5 kali pengulangan dan setiap pengulangan terdiri dari 5 botol protocorm Phalaenopsis sp  dan dikultur selama 4 minggu. Hasil penelitian menunjukkan bahwa jumlah protokrom dan tunas terbanyak dihasilkan pada konsentrasi yang sama, yaitu perlakuan air kelapa 150 ml/L (konsentrasi 15%) dengan rata-rata jumlah  64 protocorm dan 14 tunas.Kata kunci : Air kelapa (Cocos nucifera L), Phalaenopsis sp., in vitro, pertumbuhan.

Shear walls in high-rise buildings serve to increase the resistance of high-rise buildings to lateral loads. This study aims to compare the structural performance of an existing 8 (eight) storey building designed as a special moment resisting frame structure against a building designed as a dual system, which consists of: structural vibration time, base shear force, displacement, and drift. Three configurations for shear walls are designed, as follows: (1) L-shaped located at the corner of one side of the building, totaling 2 (two) units (SW1); (2) L-shaped located at the four corners of the building totaling 4 (four) units (SW2); and 3) I-shaped located along the side of the building totaling 6 (six) units (SW3). Simulations are run using the Etabs by taking into account dead loads, live loads, and earthquake loads. The results show that the addition of shear walls can: (1) reduce the vibration period of the structure up to 62,55% in SW3, (2) increase the base shear force up to 86,34% in SW3, (3) reduce peak displacement up to 84,86% in SW3, and (4) reduce the drift between floors up to 89,58% in SW3. However, the SW2 is considered to be better applied to the building by taking into account the structural performance, effectiveness and efficiency factors.