Judul: Studi morfologi dan morfometrik imago Xystrocera festiva Pascoe
Abstrak: Dewasa ini semakin banyak pengusahaan hutan tanaman monokultur. Kondisi tegakan demikian pada umumnya rentan terhadap serangan hama, misalnya serangan Hypsipylla robusta Moore pada tegakan murni mahoni (Swietenia macro- phylla King) dan serangan Xystrocera festiva Pascoe pada tegakan sengon (Paraserianthes falcataria (L) Nielsen). X. festiva (nama daerah boktor/wowolan/uter/engkes- engkes) telah banyak dilaporkan menyerang tanaman sengon sejak tahun 1897 (Koeningsberger). De Jong (1931) telah melihat semakin hebatnya serangan X. festiva ini pada tanaman sengon yang digunakan sebagai pohon pelindung pada tanaman teh (Thea cinensis L.) di Sukabumi Jawa Barat. Hama ini mempunyai daerah penyebaran yang luas meliputi Burma, Sumatera, Kalimantan dan Jawa. Dari hasil pengumpulan keterangan-keterangan tentang adanya serangan- serangan X. festiva di Indonesia oleh Lembaga Pusat Penyelidikan Kehutanan (LPPK) pada tahun 1960 ternyata bahwa X. festiva telah menyerang di setiap tempat di In- donesia dimana terdapat tanaman sengon, dengan serangan menghebat terutama terjadi di pulau Jawa. Laporan terakhir dari Matsumoto (1992) menunjukkan bahwa selain menyerang sengon, X. festiva juga menyerang tanaman Acacia mangium, Acacia auriculiformis, Albizia chinensis, hybrid (Acacia mangium X Acacia auriculiformis), Acacia vera, Acacia arabica, Acacia catecu, Pithecelobium jiringa, Pithecelobi- um dulce, Parkia speciosa, Samanea saman, Enterolobium cyclocarpum, dan Calliandra calothyrsus di daerah-daerah Ngancar (Kediri), Benakat (Sumatra Selatan), Curug Nangka, Sukaluyu, Rancamaya, Sukaraja (Bogor), Lampung Utara dan Tasikmalaya. Pengenalan X. festiva terjadi berkaitan dengan kegiatan-kegiatan pengendalian tersebut...
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Judul: Populasi larva dan banyaknya lubang gerek Xystrocera festiva Pascoe pada berbagai umur tegakan sengon (Paraserianthes falcataria (L) Nielsen
Abstrak: Salah satu spesies pohon andalan adalah Paraserianthes falcataria atau sengon. Masalah yang paling umum dihadapi dalam pengusahaan hutan tanaman sengon adalah serangan hama penggerek batang Xystrocera festiva atau dikenal juga dengan nama boktor sengon. Penelitian ini bertujuan untuk mengetahui populasi larva Xystrocera festiva dan banyaknya lubang gerek per pohon dan per hektar pada berbagai umur tegakan sengon. Data jumlah larva dan lubang gerek Xystrocera festiva ini dapat dimanfaatkan dalam pengendalian hama.
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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