Judul: Pengaruh Tingkat Ketuaan dan Pemberian Gas Asetilna terhadap Mutu Kemasakan Buah Sirsak (Annona muricata L)
Abstrak: Tanaman sirsak (Annona muricata L. ) mempunyai potensi untuk dikembangkan sebagai bahan baku industri . Beberapa masalah mutu pasca panen pada buah sirsak antara lain mudah rusak dan busuk, kemasakan buah yang tidak seragam, gejala pencoklatan sampai kehitaman pada daging buah dan timbul rasa pahit pada buah yang masak. Untuk mendapatkan hasil olahan yang bermutu baik diperlukan bahan mentah yang bermutu tinggi. Alternatif perbaikan mutu dan untuk keseragaman kemasakan buah sirsak antara lain dengan mempercepat kemasakan dengan pemberian gas asetilena.
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Judul: Pengaruh perlakuan gas etilen dan asetilen terhadap proses pematangan buah sirsak(Annona muricata L.)
Abstrak: Tujuan penelitian ini adalah untuk memperoleh kondisi pemeraman yang praktis untuk buah sirsak, dengan perlakuan gas etilen dan asetilen, sehingga diperoleh kematangan yang merata dan seragam dalam waktu yang singkat. Metode yang dilakukan dalam penelitian ini, meliputi 3 tahap penelitian: (1) penelitian meliputi aspek pemasa- ran, pemanenan dan penanganan setelah panen, (2) mencari kondisi pemeraman yang paling praktis, pada suhu dan konsentrasi gas etilen dan asetilen, (3) proses pematangan buah sirsak secara terkendali dengan zat perangsang pema- tangan gas etilen dan asetilen. Kriteria kematangan buah sirsak telah dirumuskan berdasarkan penelitian Zulfahmi pada tahun 1992. Pematangan buah sirsak menggunakan gas etilen dan asetilen dengan waktu kontak selama 24 jam, dapat mem- percepat pematangannya selama 2 hari, yaitu dari 7 hari menjadi 5 hari, terhitung dari mulai buah dipetik dari pohon; dimana suhu kamar (30°C) merupakan suhu yang paling optimum untuk pemeraman buah sirsak. Dari hasil pengamatan di lapangan, telah disusun suatu pedoman Tingkat Kematangan dalam 6 tingkatan. Tingkat Kematangan IV (TK IV) sebagai batas matang dan TK VI sebagai batas lewat matang. Selama proses kematangan, komposisi kimia buah sirsak akan berubah tiap tahap kematangan. Selama proses pematangan terjadi peningkatan total asam, kadar air, total gula, total vitamin C, total padatan terlarut,...
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Judul: Thermal Characteristics and Dynamics of Tropical Cyclone over Western North Pacific Ocean: A Case Study of Typhoon Songda (Chedeng) 2011
Abstrak: The frequent occasion of Tropical Cyclone (TC) over Western North Pacific (WNP) Ocean lies from 10˚N to 26˚N and 121˚E to 170˚E. Sources of TC development come from warm ocean temperature where latent heat is released during condensation processes and subsequently concentrated in the boundary layer. Relative humidity at 850-700 hPa is responsible to produce the most intense storm. Meanwhile, weak vertical wind shear between 850-200 hPa is one of the dynamical factors that lead to the development of TC. Pressure level of 850-200 hPa is chosen to minimize the thermodynamic effect in the lower troposphere. Typhoon Songda (Chedeng in the Philippines) or TSC lasted from May 18th to 30th, 2011 and strengthened into powerful Super Typhoon stage between May 24th and 27th. Long curving track and the exhibition of all sequences of TC life cycle, TSC is then considered as an ideal case of TC. The objective of the study with case of TSC is to investigate the role of thermal characteristics and dynamics on TC intensity. The research is carried out by using Advanced Research of Weather Research and Forecasting model (WRF ARW model) version 3.3. Two domains are employed in the model. The first domain situate from 02˚N to 40˚N and 118˚E to 149˚E and cover spatial resolution () of 33.1 km. The second domain situate from 09˚N to 27˚N and 119˚E to 132˚E with of 11 km. Timestep of the model () is 120 seconds. The model is supported by the following physical parameterization, i.e., Yonsei University Scheme (YSU) in the boundary layer, Kain-Fritsch scheme (KF) in the cumulus, and WRF Single-Moment 3-class scheme in the microphysics. Initial meteorological condition prior to the formation of the cyclone is generated using WRF ARW standard-release model. Sensitivity of the model output is obtained from a selected single-parameter change scenarios, namely, 10 % to 20 % decrease and increase of wind shear initial data at 850-200 hPa, and by 10 % to 20 % decrease of relative humidity initial data at 850-700 hPa. The result showed that the negative correlations between wind shear and intensity are found in wind shear scenarios. Wind shears of 10 ms-1 which lead to strengthening of the wind intensity in the early period of Typhoon development are found in wind shear scenarios. The effect of wind shear changes on wind intensity is statistically significant in the 20 % wind shear scenarios. During mature stage, weak wind intensity occurred when wind shear increase as given in the WRF standard-release and the 20 % decreasing scenario. Different situation is found in the 20 % increasing scenario where wind shear tend to weak and lead to strong wind intensity at this stage. Meanwhile, the reduction of moisture supply at 850-700 hPa resulting from 20 % decreasing relative humidity play a major role in the weakening of wind intensity and reduces mechanical energy of the cycle process as much as 300 J kg-1.
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