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"Cooling systems in tropical countries consume a large portion of the overall energy usage in a building, especially in tropical climates, where there is an especially high demand on cooling systems throughout the year. This paper presents a simulation of the effect of zeolite adsorbent granular size on a zeolite-water solar adsorption chiller for Universitas Indonesia. The adsorption chiller is being mathematically modeled and calculated numerically, using MATLAB®. The mathematical modeling is based on heat transfer principles inside the system for the water inlet and outlet of the system. The adsorption chiller is based on the most recent chiller developed by Shanghai Jiao Tong University (SJTU). The simulation results generally demonstrated the running characteristics of the chiller under a range of different values of granular size. The average granular sizes used in the simulation ranged from 0.5 mm to 1.5 mm. Furthermore, the simulation results showed in detail that the smaller the average granular size of zeolites, the faster the time needed to reach the maximum hot water temperature and the balance state of chilled water outlet temperature."

"Salah satu faktor penentu diperolehnya jumlah energi surya yang maksimal dengan menggunakan panel surya adalah dengan menentukan sudut arah pemasangannya (tilt Angle). Beberapa rekomendasi pemasangan sudut panel surya dengan elevasi tinggi dipandang kurang relevan terhadap kondisi area tropis yang seakan tegak lurus dengan matahari. Sudut pemasangan panel surya yang optimum di daerah tropis dipandang perlu dilakukan karena daerah tropis memiliki kharakteristik kondisi lingkungan yang berbeda dibanding dengan belahan bumi yang lain. Besar sudut optimum panel surya direpresentasikan dengan persamaan 1.15875 X + 0.001075718 Y(X merupakan lintang dan Y merupakan bujur bumi), dengan nilai RMSE 2.398 dan R square 0.979. Dari hasil perbandingan jenis panel surya, thin film terlihat lebih efektif dibanding dengan monocrystalin dan polycristalin dalam pertimbangan terhadap rata-rata suhu lingkungan di daerah tropis.

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One of determinant factor in gaining maximum solar energy collected by Photo Voltaic Panel depended on the tilt angle of the panel. Some recommendation of high elevation tilt angle was not too relevant in tropical area as upright with sun. Optimum tilt angle on tropical area need to do, because tropical area has a special environtment characteristic than other earth hemisphere. The Optimum tilt angle on tropic area represented by the equation 1.15875 X + 0.001075718 Y (X for latitude and Y for longitude), which the RMSE 2.398 and R square 0.979. The comparison result of different type solar panel is thin film was greater than monocrystalin and polycrystalin based on tropic ambient temperature average."

"Komunitas anggrek (Orchidaceae) merupakan salah satu kelompok tumbuhan yang terancam terhadap stres kekeringan akibat perubahan iklim. Komunitas anggrek di Indonesia mengembangkan dua bentuk hidup utama, yaitu epifit dan terestrial. Penelitian bertujuan untuk membandingkan adaptasi anatomi daun dan akar antara anggrek epifit dan terestrial; membandingkan tingkat adaptasi terhadap stres kekeringan antara bentuk hidup epifit dan terestrial pada spesies anggrek toleran terang; membandingkan tingkat adaptasi terhadap stres kekeringan antara bentuk hidup epifit dan terestrial pada spesies anggrek toleran naungan; serta membandingkan tingkat adaptasi terhadap stres kekeringan antara spesies Eulophia spectabilis dari tropis basah dan E. petersii dari tropis kering. Analisis anatomi dilakukan dengan pengamatan sayatan paradermal dan sayatan melintang daun maupun akar. Analisis fisiologi dilakukan secara eksperimental dengan perlakuan kekeringan di rumah kaca selama 30 hari. Hasil penelitian menunjukkan terdapat perbedaan strategi adaptasi anatomi daun dan akar antara anggrek epifit dengan terestrial. Anggrek epifit lebih mengutamakan penyesuaian ketebalan dan luasan jaringan penyusun organ daun maupun akar, sedangkan anggrek terestrial lebih mengutamakan penyesuaian luasan komponen pembuluh angkut daun dan akar, serta jumlah stomata dan luasan total stomata. Pada spesies anggrek toleran terang, kelompok epifit memiliki tingkat adaptasi yang lebih tinggi terhadap stres kekeringan dibandingkan kelompok terestrial. Pada spesies anggrek toleran naungan, kelompok epifit memiliki tingkat adaptasi terhadap stres kekeringan dengan rentang variasi yang lebih lebar dan tidak berbeda nyata dengan kelompok terestrial. Spesies Eulophia petersii dari tropis kering memiliki tingkat adaptasi yang lebih tinggi terhadap stres kekeringan dibandingkan Eulophia spectabilis dari tropis basah. Ciri anatomi pada komunitas anggrek tropis Indonesia terkait tingkat adaptasi yang lebih tinggi terhadap stes kekeringan meliputi: jaringan mesofil dan daun yang lebih tebal; lapisan kutikula yang lebih tebal; jaringan hipodermis yang berkembang; komponen pembuluh angkut daun yang lebih sempit, jaringan sklerenkim yang berkembang baik di sekitar pembuluh angkut primer daun; stomata dengan ukuran lebih besar, jumlah lebih sedikit, dan area total stomata yang lebih sempit; komponen pembuluh angkut akar yang lebih sempit; dan jaringan velamen yang lebih berkembang. Ciri fisiologi pada komunitas anggrek tropis Indonesia terkait tingkat adaptasi yang lebih tinggi terhadap stes kekeringan meliputi: selisih prolin yang lebih kecil, laju penurunan kandungan air relatif jaringan daun yang lebih rendah, dan nisbah klorofil a/b yang lebih tinggi.

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The orchid community (Orchidaceae) is one of the most threatened plant's groups to drought stress due to climate change. Indonesian orchid community has developed two main life forms, as epiphyte and terrestrial. The aims of this study were to compare the anatomical adaptation of leaf and root between epiphytic and terrestrial life forms on the Indonesian tropical orchid community; to compare the adaptation level to drought stress between epiphytic and terrestrial life forms in sun-tolerant orchid species; to compare the level of adaptation to drought stress between epiphytic and terrestrial life forms in shade-tolerant orchid species; to compare the level of adaptation to drought stress between orchid Eulophia spectabilis from wet tropical and E. petersii from dry tropical. The anatomical analysis was performed with observations on paradermal and transverse sections of leaves and roots. The physiological analysis was conducted experimentally in the greenhouse with drought treatment for 30-days. The results showed that epiphytic orchids have prioritized the anatomical adaptation strategy by adjusting the thickness and area of leaf and root's tissues, while the terrestrial orchids through the adjustment of the area of leaf and root's vascular components, as well as the number and total area of stomata; in sun-tolerant species, epiphytic orchids have shown a higher adaptation level to drought stress than terrestrial orchids; in shade-tolerant species, epiphytic orchids have shown a wider range of adaptation level to drought stress and not significantly different with terrestrial orchids; Eulophia petersii from dry tropical showed a higher adaptation level to drought stress than E. spectabilis. The anatomical traits related to a higher adaptation level to drought stress were: thicker mesophyll and leaf tissue, thicker cuticle layer, well developed hypodermic tissue, narrower leaf vascular bundle components, well developed sclerenchyma tissue around the leaf's primary vascular bundle, broader size-but fewer stomata, narrower total stomatal area, narrower root vascular components, and a more developed velamen layer. The physiological traits related to a higher adaptation level to drought stress were: lower proline deviation, lower decline rate in leaf water content, and a higher chlorophyll a/b ratio. "

"Forest fire is a massive threat towards tropical forest causing various negative impacts to nature and human being. Forest fire often leads to alteration of forest structure and its functions. This study of tree growth after forest fire was conducted using a model simulation. The model was performed at the individual level of plant community and built to analyze the potential of tree growth and its scenario for post-fire recovery. Five important tree species from montane forest of Mount Ciremai were chosen to build the model based on four main parameters i.e. plant growth rate, diameter at breast height (DBH), tree-to-grass competition and tree-to-tree competition. The scenario of post-fire recovery was performed by replanting similar species with 5 cm DBH seedling. Prediction from our model showed that most of the chosen species would recover to its pre-fire condition after 37 - 50 years. Considering the limitation of competition after re-planting, it was suggested to minimize tree to tree competition and applied silvicultural treatments to maximize tree growth and tree community recovery."

"Substrat makrofita memengaruhi kelimpahan dan keanekaragaman struktur komunitas epifiton. Mikroalga yang berpotensi bersifat perifitik menjadi komponen penyusun struktur komunitas epifiton. Berdasarkan penelitian sebelumnya, epifiton pada Utricularia berkeanekaragaman sedang dengan Cosmarium dan diatom sebagai penyusun utama komunitas epifiton, sementara epifiton pada Hydrilla dan Chara yaitu Closterium, Cosmarium, Euastrum, Micrasterias, Pleurotaenium, dan Staurastrum. Penelitian ini bertujuan mengetahui perbedaan antara struktur komunitas epifiton pada Utricularia sp. dengan Hydrilla sp. dan mengetahui plankton yang berpotensi menjadi epifiton di Situ Alam FMIPA UI. Komponen yang dikaji yaitu kelimpahan dan keanekaragaman epifiton. Penelitian dilakukan pada bulan Maret 2018 hingga Mei 2018 menggunakan metode purposive sampling dan mengambil sampel epifiton pada Utricularia sp., Hydrilla sp., gelas objek, dan plankton pada sampel air. Pengambilan tiap sampel dilakukan 3 kali dengan pengulangan 1 kali dalam jarak waktu 2 minggu. Penelitian menunjukkan 67 genus dengan 1 genus planktonik yang hanya ditemukan di sampel gelas objek saja. Kelimpahan epifiton pada Utricularia sp. sebanyak 84.609 sel/ml, lebih tinggi dibanding epifiton pada Hydrilla sp. yaitu 74.392 sel/ml. Nilai keanekaragaman epifiton pada kedua tanaman tersebut dikategorikan keanekaragaman rendah H rsquo;< 2,302. Keanekaragaman komunitas epifiton pada Utricularia sp. berbeda dengan komunitas epifiton pada Hydrilla sp. P0,05.

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Macrophytes as substrate affect abundance and diversity in community structure of epiphyton with periphytic microalgae become part of it. Previous research showed medium diversity of epiphyton on Utricularia mostly consists of Cosmarium and diatom, also Closterium, Cosmarium, Euastrum, Micrasterias, Pleurotaenium, and Staurastrum was found on epiphyton of Hydrilla and Chara.

The purpose of this research is to know the differences between community structure of epiphyton on Utricularia sp. and Hydrilla sp., also to know planktons that become epiphyton at Situ Alam FMIPA UI. Abundance and diversity of epiphyton community are the main discussion in this research.

Research begins on March 2018 until May 2018. Using purposive sampling method, samples were taken from Utricularia sp., Hydrilla sp., object glass, and water. Each sample was taken thrice, one repetition, once every 2 weeks.

Research shows 67 genera, including 1 planktonic genus that was found only on object glass. The abundance of epiphyton on Utricularia sp. shows 84.609 cell ml, higher than 74.392 cell ml that was found on epihyton of Hydrilla sp. Both diversity indices are categorized as low diversity."