Judul: Pertumbuhan Anakan Kapur Tanduk (Dryobalanops lanceolata Burck.) pada Berbagai Tingkat Penutupan Kanopi di KHDTK Haurbentes, Jasinga
Abstrak: Deforestasi hutan telah berdampak pada produktivitas hutan terutama pada kelompok jenis komersial, seperti jenis Dipterocarpaceae sehingga perlu dilakukan upaya rehabilitasi untuk keberlanjutan produksi. Jenis Dryobalanops lanceolata Burck. merupakan salah satu jenis dari famili Dipterocarpaceae yang pertumbuhannya termasuk cepat yang dapat dijadikan pilihan jenis untuk rehabilitasi. Penelitian ini bertujuan menganalisis persentase penutupan kanopi yang baik untuk pertumbuhan anakan D.lanceolata. Penelitian ini menggunakan hubungan regresi antara diameter dan tinggi tanaman dengan persentase penutupan kanopinya. Persamaan dengan fungsi rasio merupakan model yang dapat menjelaskan hubungan paling baik antara pertumbuhan anakan D.lanceolata dengan penutupan kanopinya. Adanya penutupan kanopi sebesar 31% - 37 % mampu memberikan pertumbuhan tinggi antara 70.6-75.5 cm untuk anakan D.lanceolata dan penutupan kanopi sebesar 29% - 31% mampu memberikan pertumbuhan diameter antara 11.6-11.7 mm.
Keyword: deforestasi, Dryobalanops lanceoalata, penutupan kanopi, pertumbuhan, rehabilitasi

Judul: The Effect of Canopy on Growth of Dryobalanops lanceolata Burck. in The Age at KHDTK Haurbentes, Jasinga
Abstrak: Jenis-jenis Dipterocarpaceae menjadi andalan dalam produk-produk hasil hutan berupa kayu pertukangan. Upaya melestarikan jenis-jenis Dipterocarpaceae, maka Badan Penelitian dan Pengembangan telah membangun Hutan Tanaman koleksi Dipterocarpaceae seluas 60 ha di Kawasan Hutan Dengan Tujuan Khusus (KHDTK) Haurbentes, Kabupaten Bogor, Provinsi Jawa Barat. Penelitian ini bertujuan untuk mengetahui persentase tutupan tajuk yang optimal dan karakteristik lingkungan yang tepat untuk pertumbuhan D. lanceolata. Data primer didapat dengan melakukan pengukuran dan pengamatan terhadap pertumbuhan D. lanceolata berupa diameter setinggi dada, tinggi pohon, tingkat tutupan tajuk dan kondisi lingkungan (temperatur dan kelembaban). Data sekunder berupa data pertumbuhan awal saat D. lanceolata baru ditanam dan kondisi umum lokasi penelitian. Pertumbuhan diameter dan tinggi D. lanceolata dipengaruhi oleh tutupan tajuk namun memiliki korelasi yang rendah. D. lanceolata dapat tumbuh pada rentang persentase tutupan tajuk sebesar 40% - 65% dan akan tumbuh dengan optimal apabila persentase tutupan tajuk dibawah 65%., Dipterocarp species are the mainstay of forest products in the form of carpentry wood. In an effort to preserve the Dipterocarpaceae species, the Research and Development Agency had established a 60 ha collection of Dipterocarp Forest Plantation in forest area with special purpose (KHDTK) Haurbentes, Bogor Regency, West Java Province. This study aims to determine the percentage of optimal canopy cover and appropriate environmental characteristics for the growth of D. lanceolata. Furthermore, primary data were obtained by measuring and observing the growth of D. lanceolata in the form of diameter at breast height, tree height, canopy cover level and environmental conditions (temperature and humidity). Meanwhile, secondary data, which was in the form of initial growth data when D. lanceolata, was newly planted and the general condition of the study site. The growth of diameter and height of D. lanceolata was influenced by canopy cover but had a low correlation. In addition, D. lanceolata can grow in the canopy cover percentage range of 40% - 65% and it will grow optimally if the percentage of canopy cover is below 65%.
Keyword: canopy, diameter, Dryobalanops lanceolata, height, growth

Judul: Exergy Analysis of Membrane Utilization for Solution Separation in LiBr-H2O Absorbtion Refrigeration System
Abstrak: Absorbtion refrigeration system provides prominent advantages in tems of environmental impact and energy consumption. Absorbtion refrigeration system uses natural refrigerant, such as water, which gives no harm to the environment. In terms of energy consumption, it requires heat to regenerate refrigerant from its absorber and provide the refrigeration effect. This form of energy is preferred since heat can be supplied from various sources, including waste heat and renewable energy, and thermodynamically categorized as low quality energy. However, effectiveness of refrigerant regeneration could only be obtained if the temperature is high enough. In this study, the heat utilization in the regeneration process will be eliminated by introducing membranes for separating the refrigerant from the absorber. Specifically, the objectives of this research are to :1) to study the absorbtion mechanism of water vapor by LiBr-H2O solution in a controlled condition, 2) to study the regeneration process of LiBr-H2O using reverse osmosis (RO) membrane and vacuum membrane distillation (VMD) when applied in LiBr-H2O absorbtion refrigeration system, 3) to perform the energy and exergy analysis in LiBr-H2O absorbtion refrigeration system using RO membrane. The membrane was used as a tool to separate the refrigerant from absorbent which performs as regeneration process in conventional absorbtion system. As separation component, RO membrane employs pressure to oppose the osmotic pressure and pass certain component through the pores. While, VMD employs vacuum pressure and thermal, so that the substance to be transported through the membrane is in form of vapor. The result shows that absorbtion rate of water vapor by LiBr-H2O solution was influenced by solution concentration, temperature, humidity and pressure. The highest absorbtion rate was 0.031 g/minute which was occurred at temperature 40°C, RH 70% and solution concentration 60%. Prediction model was developed to calculate the absorbtion parameter inspite of P-T-X diagram.The highest water vapor absorbtion in absorber using spiral wound module-based RO membrane occurred at initial concentration of 30%, wich is the highest concentration used in the experiment. Increasing of operation pressure during separation process will increase permeation flux but decrease rejection factor.Unexpectedly, permeate of the RO membrane still contain LiBr at concentration 7w/w %-9w/w%, which affect the achievable cooling temperature and cooling capacity. Optimization of regeneration using VMD was conducted with response surface methodology (RSM) and the result show that highest permeate flux (0.93 kg.m-2.s-1) can be achived at initial concentration of 47.5%, temperature of 80°C and flow rate of 1.9 L.min-1.COP obtained in absorbtion refrigeration system using RO membran with initial concentration 20% was in the range of 1.147-1.171. Exergy analysis shows that increasing pressure of RO membrane at concentration 20% increased the irreversibity.On the other hand, exergy analysis on VMD shows that higher concentration and temperature will increased irreversibility.
Keyword: refrigeration, absorbtion, reverse osmosis, vacuum membrane distillation, energy, exergy