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Ditemukan 15311 dokumen yang sesuai dengan query
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"The development of methods in measuring the photosynthesis process is now increasingly widespread, especially to get a more efficient method and fast. Photosynthesis efficiency of micro-algae periphytic has been estimated under the influence of light intensity and temperature by using the fluorescence monitoring system. the measurement on a colonized substrate by the saturation pulse method has been conducted using a FMSI(Fluorescence Monitoring Systems,Hansatech). Measurement of the fluorescence parameters was conducted every week on algal periphyton which was cultivated on the articial substrate during for 5 weeks under light and temperature conditions. The results show that fluorecence maximal value (Fm) increase linearly with chlorophyll a concentrations. For 20 derajat C (experiment where the biomass reached higher values),up to 100 mg chlorophyll a.m min 2 the change in Fm is approximately linear. After,the response of Fm is hyperbolic, sugesstting a measure in vivo chlorophyll a flurescence of periphyton in laboratory conditions. The instrument is simple to use, with convenient software control, especially when used in PC mode. "
2010
551 LIMNO 17:1 (2010)
Artikel Jurnal  Universitas Indonesia Library
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Hamim
"The experiment aimed to examine the growth and some physiological parameters of five metal-accumulator weed species in response to mercury (Hg) and lead (Pb) treatment. Five weed species (Branchiaria mutica, Cyperus kyllingia, Ipomea aquatica, Mikania micrantha, and Paspalum conjugatum) were grown in water culture using half strength Hoagland’s solution and subjected to Hg(NO3)2 and PB(NO3)2 at 0,  0.25 and 0.5 mM for 3 weeks. The growth, photosynthesis, lipid peroxidation and proline content were observed during the treatments. The result showed that both Hg and Pb decreased growth significantly, but the decrease was far higher in Hg than in Pb treatments. Hg treatment reduced photosynthetic rate dramatically under different photosynthetic photon flux density suggesting that heavy metal Hg until 0.5 mM caused the damage of photosynthetic apparatus almost all species except in I. aquatica. Hg and Pb treatment caused dramatic increase in leaf MDA content, which was associated with the decrease of chlorophyll content significantly. Almost all the species were tolerant to Pb treatment up to 0.5 mM except M. micrantha, while only C. kyllingia and I. aquatica were tolerant to Hg treatment up to 0.5 mM. Only Hg treatment and not Pb that induced higher proline content in the leaves of threated plants without clear pattern of the increment among the species suggesting that proline may have a role as alarm stress rather than tolerant indicator."
Bogor: Seameo Biotrop, 2020
634.6 BIO 27:3 (2020)
Artikel Jurnal  Universitas Indonesia Library
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Clayton, Roderick K.
Cambridge, UK: Cambridge University Press, 1980
572.46 CLA p
Buku Teks  Universitas Indonesia Library
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"The analysis of daily curves of dissolved oxygen in the Garonne, downstream of Toulouse, shows that the river is generally heterotrophic. It appears in contradiction with the fact that the river bed is covered with a thick periphytic biofilm. From the data obtained in-vitro and in-situ, we developed a model to calculate the net production, integrated over the section. This model makes it possible to simulate various environmental situations: variations of the wet cross section, seasons and turbidity. The simulations show that some zones of the section are highly productive. For the majority of the cases, the daily balance photosynthesis/respiration remains less than one. This negative daily balance is equilibrated by the re-aeration rate associated with the turbulent flow of the Garonne. This work shows, however, that the oxygen level in the river is strongly dependent on the total rate of respiration, so that a weak increase (pollution for example) could quickly induce a reduction in the dissolved oxygen"
2010
551 LIMNO 17:2 (2010)
Artikel Jurnal  Universitas Indonesia Library
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"Skipjack tuna is an important species targeting by pole and line fishery in Bone Bay. The distribution and abundance of this species tended to aggregate to the preferred bio-physical environments. To describe the short term relationship between skipjack tuna and oceanographic conditions and to visualize the predicted high catch areas, remotely sensed satellite based-oceanographic sea surface temperature (SST) and chlorophyll-a together fisheries data were used. Results indicated that the highest skipjack CPUEs were mainly found in coastal areas of Palopo and Kolaka both in 2007 and in 2009 during the period of study. The high tuna concentrations corresponded well with chlorophyll-a of 0.15-0.40 mg mg-3 and SST of 29.0-31.5 °C. The preferred ranges provide a good indicator for initially detecting potential skipjack fishing grounds. This study suggested that thermal and chlorophyll fronts as well as upwelling may important mechanisms in explaining the temporal and spatial dynamics of skipjack tuna distribution and abundance in Bone Bay."
620 JITK 3:1 (2011)
Artikel Jurnal  Universitas Indonesia Library
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Wira Indrayani
"The rain attenuation of down-link radio wave signals from the Superbird-C satellite and surface rainfall data have been
used to estimate the parameters of exponential raindrop size distribution (DSD) at Koto Tabang (100.32 E, 0.20 S),
West Sumatra, Indonesia. Prior to analyzing the measured data, the ability of the method to recover the parameters of
known DSDs from which the samples were taken was examined. It was found that the method can accurately retrieve
the input parameter of the sample. Only six case studies are presented here, so the results are representative rather than
definitive. The method successfully estimated the DSD parameters of a stratiform case with steady intensity and deep
convective rains of a short duration. This can be inferred from the small difference between the parameters derived from
rain attenuation data and those derived from a 2D video disdrometer. The poor performance of the method was
observed for a stratiform case with strong rain intensity fluctuation and shallow convective rains with very low rain top
height. This phenomenon is probably due to the bias that may be inherent in the estimation of specific rain attenuation,
such as the assumption of a constant path length throughout the rain.
Penentuan Parameter Distribusi Butiran Hujan dari Data Atenuasi Gelombang Elektromagnetik Satelit
Telekomunikasi Berfrekuensi Ku-Band. Data atenuasi sinyal down-link dari gelombang radio satelit Superbird C dan
data curah hujan permukaan telah dimanfaatkan untuk menghitung parameter eksponensial distribusi butiran hujan
(DSD) di Koto Tabang, Sumatera Barat, Indonesia. Pengujian metode terhadap data uji dengan parameter DSD yang
diketahui menunjukkan bahwa metode ini dapat dengan akurat menghitung kembali parameter tersebut. Metode ini
telah diujikan pada masing-masing dua studi kasus untuk hujan stratiform, deep dan shallow convective. Kemampuan
metode ini untuk memperkirakan parameter DSD dari hujan stratiform dengan intensitas curah hujan yang stabil dan
hujan deep convective dengan durasi singkat, sangat baik. Hal ini ditandai dengan kecilnya perbedaan antara parameter
DSD yang berasal dari atenuasi hujan dan dari data 2D-Video disdrometer (2DVD). Kurang baiknya kinerja metode ini
teramati pada hujan stratiform dengan fluktuasi intensitas curah hujan yang besar dan dan hujan shallow convective
dengan ketinggian puncak hujan yang sangat rendah. Fenomena ini kemungkinan disebabkan oleh bias dalam
memperkirakan spesifik atenuasi seperti bias akibat asumsi panjang lintasan penjalaran yang konstan selama hujan."
Universitas Andalas, Department of Physics, Faculty of Mathematics and Natural Science, 2016
AJ-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Diaz Ramadhan
"
Klorofil merupakan sekelompok pigmen amfifilik berwarna hijau yang memainkan peran
penting dalam proses fotosintesis. Ekstraksi dari klorofil secara tradisional kebanyakan akan
melibatkan teknik yang destruktif dan dapat mendegradasi molekul klorofil sehingga akan
mengurangi properti dari fungsionalitas senyawa. Dengan kemajuan teknologi, teknik untuk
ekstraksi klorofil dapat dilakukan dengan metode non-destruktif. Penelitian ini
memanfaatkan perkembangan teknologi tersebut dengan mencoba untuk
mengaplikasikannya untuk memprediksi kandungan klorofil berdasarkan varietas daun
menggunakan citra multispectral pada model ML dengan arsitektur CNN (Convolutional
Neural Network). Penelitian ini dilakukan dengan mencari sampel dari varietas daun untuk
mendapatkan populasi data, sampel-sampel tersebut akan diambil citranya dan diproses
sehingga tercipta suatu dataset yang dapat digunakan. Dataset-dataset ini selanjutnya akan
diberi beberapa perlakuan berbeda dan akan dicabangkan dengan augmentasi yang akan
menjadi varian dataset. Model dari arsitektur CNN yang digunakan berupa AlexNet dan
ResNet-18 yang dilatih untuk mendapatkan model regresi. Analisa dari hasil akan dilakukan
dengan mencari hasil akhir metrik R2 dan RMSE yang akan dibandingkan untuk uji
performa pada tiap dataset dengan model yang digunakan. Berdasarkan model yang telah
dilatih, dataset dengan performa terbaik berupa dataset 6 Channel dengan nilai pada model
AlexNet dengan parameter RMSE sebesar 8.02 pada label latih dan 8.76 pada label validasi,
dengan nilai R2 sebesar 0.84 pada label latih dan 0.79 pada label validasi. Sedangkan pada
model ResNet, dataset 6 Channel masih memiliki nilai performa terbaik pada kedua metrik
parameter. Namun, pada model ResNet, seluruh dataset mengalami penurunan performa
yang jauh dibanding model AlexNet, hal ini dapat disebabkan oleh sampel dataset yang
diambil maupun perlakuan dari dataset yang digunakan pada model ini.

Chlorophyll is a group of green amphiphilic pigments that play an important role in the
process of photosynthesis. Extraction of chlorophyll traditionally mostly involves
destructive techniques and can degrade the chlorophyll molecules, thereby reducing the
functional properties of the compounds. With the advancement of technology, techniques
for chlorophyll extraction can be done with non-destructive methods. This research utilizes
these technological developments by trying to apply them to predict chlorophyll content
based on leaf varieties using multispectral images in the ML model with CNN
(Convolutional Neural Network) architecture. This research is carried out by finding
samples of leaf varieties to obtain population data, these samples will be taken and processed
to create a dataset that can be used. These datasets will then be given several different
treatments and will be branched out with augmentation which will become variant datasets.
The models of the CNN architecture used in the form of AlexNet and ResNet-18 are trained
to obtain a regression model. Analysis of the results will be done by finding the final results
of the R2 and RMSE metrics which will be compared for performance testing on each dataset
with the model used. Based on the models that have been trained, the dataset with the best
performance is the 6 Channel dataset with a value on the AlexNet model with RMSE
parameters of 8.02 on the training label and 8.76 on the validation label, with an R2 value
of 0.84 on the training label and 0.79 on the validation label. While in the ResNet model,
the 6 Channel dataset still has the best performance value on both parameter metrics.
However, in the ResNet model, all datasets experience a significant decrease in performance
compared to the AlexNet model, this can be caused by the dataset samples taken or the
treatment of the datasets used in this model.
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Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2024
S-pdf
UI - Skripsi Membership  Universitas Indonesia Library
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Talib Hussain
"A
vacuum drying system is being designed and developed at National Institute of
Vacuum Science & Technology (NINVAST) to dry various materials under vacuum
conditions. Its performance and capabilities are tested by carrying out
different experiments on green (freshly cut) wood samples of Poplar and
Eucalyptus with dimensions of 990.6 mm x 76.2 mm x 25.4 mm and 469.9 mm x 50.8
mm x 25.4 mm, respectively. These samples were dried from green moisture
content (MC) 78% to 10% by this system at ultimate vacuum of about 1.6 x 103
pascal and at a temperature ranging from 35oC to 55oC for
about 20 hrs. Drying quality tests included: prong test, warp measurement,
surface checking and moisture content measurement, which were all performed.
The resulting wood samples showed no dislocation and no excessive stress
buildup. If compared to ordinary drying process, the vacuum drying is rapid and
the drying rate increases with rise in temperature. The designed system is
beneficial for commercial use."
2016
J-Pdf
Artikel Jurnal  Universitas Indonesia Library
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Talib Hussain
"A vacuum drying system is being designed and developed at National Institute of Vacuum Science & Technology (NINVAST) to dry various materials under vacuum conditions. Its performance and capabilities are tested by carrying out different experiments on green (freshly cut) wood samples of Poplar and Eucalyptus with dimensions of 990.6 mm x 76.2 mm x 25.4 mm and 469.9 mm x 50.8 mm x 25.4 mm, respectively. These samples were dried from green moisture content (MC) 78% to 10% by this system at ultimate vacuum of about 1.6 x 103 pascal and at a temperature ranging from 35oC to 55oC for about 20 hrs. Drying quality tests included: prong test, warp measurement, surface checking and moisture content measurement, which were all performed. The resulting wood samples showed no dislocation and no excessive stress buildup. If compared to ordinary drying process, the vacuum drying is rapid and the drying rate increases with rise in temperature. The designed system is beneficial for commercial use."
Depok: Faculty of Engineering, Universitas Indonesia, 2016
UI-IJTECH 7:5 (2016)
Artikel Jurnal  Universitas Indonesia Library
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Ignasius Ferdie
"Saat ini, sistem penerangan merupakan salah satu penggunaan energi listrik yang besar. Dengan penggunaan lampu, kegiatan manusia dapat berlangsung sepanjang hari dan malam. Semakin tingginya tingkat aktifitas akan mempengaruhi intensitas cahaya yang dibutuhkan. Dalam hal tersebut, dibutuhkan pengupayaan penghematan energi pada sistem penerangan.
Pada skripsi ini, komponen utama sensor dalam sistem pengaturan intensitas cahaya adalah LDR (Light Dependant Resistor). Sistem ini akan berjalan optimal apabila didukung dengan peralatan yang berkualitas dan juga pengkalibrasian yang tepat. LDR sebagai komponen pasif akan mendapatkan perubahan hambatan listrik sebagai reaksi terhadap perubahan intensitas cahaya. Nilai pengaturan (set point) lux pada sensor cahaya berguna sebagai acuan dasar mikro prosesor dalam mengatur intensitas cahaya keluaran pada LED (Light Emitting Diode).
Dalam simulasi Proteus dan Envision Project, terbukti bahwa sensitifitas sensor sangat berpengaruh terhadap berjalannya sistem pengaturan intensitas cahaya. Pengkalibrasian dua titik pada program Envision Project sangat berguna dalam mendapatkan nilai lux yang diharapkan. Dalam pengujian dan perhitungan efisiensi energi, terbukti bahwa dengan mengaplikasikan sistem pengaturan intensitas cahaya (dimmer), efisiensi energi mencapai 65% tanpa memperhitungkan faktor-faktor lainnya. Selain penghematan energi listrik, kenyamanan kerja dan meningkatknya performa pekerja akan terjadi seiring dengan pengaturan intensitas cahaya pada gedung perkantoran.

Nowadays, the lighting system is one of the major usage of electrical energy. With the use of light, human activities can take place throughout the day and night. Increasing levels of activity will affect the intensity of light required. In that case, it needs the effort for energy savings on lighting systems.
In this final project, the main sensor component used in the light intensity system setting is the LDR (Light Dependant Resistor). This system will run optimally when supported with the good quality equipment and proper calibration. LDR as a passive component will get an alteration in electrical resistance in response to the change of light intensity which fall on to the sensor. Setting of lux value (set point) at a light sensor is the basic reference for the microprocessor in adjusting light intensity output of the LED (Light Emitting Diode).
In Proteus simulation and Envision Project, it is proved that the sensitivity of the sensor affects the function of the light intensity controller. Two points calibration on Envision Project program is very useful in getting the expected intensity value. In the testing and calculation of energy efficiency, it is proved that by applying light intensity (dimmer) control system, energy savings could reach 65% of total energy without consider other factors. Beside electrical energy savings, the comfort of working and the increase performance of workers will be occur proportionally with the light intensity settings in an office buildings.
"
Depok: Fakultas Teknik Universitas Indonesia, 2013
S54661
UI - Tugas Akhir  Universitas Indonesia Library
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