Judul: Pengaruh Manajemen Naungan Stup terhadap Aktivitas Terbang `Galo-galo (Trigona drescheri) di Sumanik Sumatera Barat
Abstrak: Trigona drescheri merupakan spesies stingless bees yang berpotensi memproduksi propolis dan produktivitasnya dipengaruhi oleh aktivitas terbang pekerja. Atap asbes dan PVC digunakan sebagai naungan dalam penelitian ini dengan tujuan memperoleh informasi tentang aktivitas terbang lebah Trigona. Pengamatan dilakukan selama 10 menit per jam, yakni dari pukul 07.00-18.00. Suhu udara, kelembaban relatif, dan intensitas cahaya juga diukur. Waktu pengamatan pada pukul 07.00-17.00 meningkatkan aktivitas terbang lebah dan mencapai jumlah tertinggi antara pukul 15.00-17.00, kemudian menurun hingga pukul 18.00. Suhu udara (r=0.980 dan R2 =0.962 pada asbes; r=0.976 dan R 2 =0.953 pada PVC) dan kelembaban relatif (r=0.979 dan R2 =0.960 pada asbes; r=0.984 dan R2 =0.970 pada PVC) nyata (P<0.05) mempengaruhi aktivitas terbang T. drescheri. Intensitas cahaya tidak berpengaruh terhadap aktivitas terbang. Suhu 25-30 oC dan kelembaban relatif 60%-78% merupakan kondisi optimal bagi T. drescheri untuk beraktivitas terbang. Stup yang diletakkan di bawah atap PVC menghasilkan aktivitas terbang lebah yang nyata lebih tinggi (P<0.05) dari pada atap asbes.
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Judul: Aktivitas Terbang dan Produktivitas Lebah Trigona laeviceps pada Bahan Stup Kayu Sengon dan Kayu Lapis (Plywood)
Abstrak: Trigona laeviceps is one of stingless bees species which produce propolis and its productivity influenced by flight activity of the workers. This study aimed to obtain stup material place Trigona hive which may improve the weight of bees colony and increase production of propolis. The weight gain of colony was counted every week while propolis+bee pollen and honey was measured at the end of the study. Temperature, internal temperature, relative humidity, light intensity and wind speed were also measured. Daily flight activity of Trigona for obtain pollen/resin and nectar/water on sengon stup was very significantly higher (p<0.01) compared to the bees kept in plywood stup (80.40±41.40 vs 42.33±21.90 bees/day). The light intensity affect the daily flight activity (R2=78.3% in sengon stup and R2= 85.6% in stup plywood). Colony weight gain on sengon stup was significantly higher (p<0.05) as compared to those on plywood stup (23.70 vs -−8.44 g/week). Whereas the production of propolis+bee pollen and honey were not significantly different (24.77 and 19.66 vs 19.92 and 17.61 g/8 weeks).
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Judul: Characterizations of low alloy steel sae 4422  plated with chromic acid (Cro3)
Abstrak: Characterizations of low alloy steel SAE 4422 plated with chromic acid (CrOrO3) was use Optical Microscopy (OM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), RD),Energy Dispersive Analysis of X-Ray (EDAX), Hardness Test and Roughness Test. Microstructures analysis exhibits cracks and grain boundaries microcracks as a characteristics of chrome metal found at plating metal. Perlite and Ferrite as grains of steel found at base metal with grain boundaries around it. Phase analysis of plating metal appropriate to chrome metal with lattice constant (a) is 2.559 Å and phase analysis of base metal appropriate to iron ferrite with lattice constant (a) is 3.318 Å. Both plating and base metal have cubic system. Chemical analysis of plating metal at surface section exhibits that cracks area have highest value of carbon element compare with grains and grains boundaries area. While chemical analysis of base metal at cross section exhibits that perlite have highest value of carbon element compare with ferrite and grain boundaries. The hardness value of plating metal at surface section and cross section are 753 and 637 VHN. While, the hardness value of base metal and interface area at cross section are 205 and 373 VHN. The roughness value at measurement points of chrome surface for as received sample are 0.445 μm. Observation used Optical Microscopy and Scanning Electron Microscopy exhibits surface irregularities combine to form surface texture of plating metal at surface section.
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