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"Growth and yield of plants are increased when plants are provided with mixtures of nitrate and ammonium compared with either form alone. Therefore, the objective of this experiment was determine the optimum of nitrate and ammonium ratio caused an increased in growth and yield of green pak choy (Brassica chinensis L.) The experiment was designed in Randomized Completely Design with five treatments of nitrate ammonium ratios and arranged in four replication. The treatments of nitrate ammonium ratio were : 100/0; 75/25; 50/50; 25/75 and 0/100. The results showed that nitrogen fertilizer applied in mixture nitrate and ammonium gave different effects in leaf nitrate reductase activity, leaf nitrogen content, growth and yield of green pak choy. There was significant correlation between the leaf nitrate reductase activity and leaf nitrogen content. There was also significant correlation between the leaf nitrate reductase activity with growth and yield of green pak choy. Nitrate ammonium ratio at 75/25 and 50/50 have better affect on the leaf nitrate reductase activity, leaf nitrogen content, growth and yield of green pak choy"

"Kelimpahan fitoplankton di suatu Situ tergantung pada kandungan nitrat dan fosfat. Konsentrasi kandungan nitrat dan fosfat di suatu situ dipengaruhi oleh buangan limbah. Kandungan nitrat dan fosfat dapat mempengaruhi keberadaan fitoplankton. Tujuan penelitian ini adalah untuk mengetahui seberapa kuat hubungan antara kandungan nitrat dan fosfat dengan kelimpahan fitoplankton, dan mengetahui parameter fisika-kimia di Situ Kenanga. Materi yang digunakan dalam penelitian ini adalah air sampel untuk uji nitrat dan fosfat dan sampel fitoplankton yang berasal dari Situ Kenanga. Sampling dilakukan pada bulan Oktober 2020 hingga Januari 2021 pada musim hujan, oleh karena kondisi lingkungan pada perairan sangat bergantung pada musim. Sampling dilakukan selama 3 minggu di 3 stasiun yang berbeda. Masing-masing stasiun terdiri dari 3 titik. Uji kandungan nitrat dan fosfat serta pencacahan fitoplankton dilakukan di laboratorium. Hasil penelitian menunjukkan kandungan nitrat di Situ Kenanga berkisar antara 2.29 mg/L - 3.89 mg/L. Kandungan nitrat tergolong baik sehingga optimal untuk pertumbuhan fitoplankton. Kandungan fosfat berkisar antara 0.3 mg/L - 0.5 mg/L. Kandungan fosfat tergolong tinggi namun masih dapat ditolerir oleh fitoplankton. Kelimpahan fitoplankton di Situ Kenanga berkisar antara 303.05 Sel/L – 727.65 Sel/L. Terdapat hubungan yang sangat kuat antara kandungan nitrat dan fosfat dengan kelimpahan fitoplankton di Situ Kenanga ( r = 0.99)

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The abundance of phytoplankton in a Situ depends on the content of nitrate and phosphate. The concentration of nitrate and phosphate content in a site is affected by the discharge of waste. The content of nitrate and phosphate can affect the presence of phytoplankton. The purpose of this study was to determine how strong the relationship between nitrate and phosphate content with the abundance of phytoplankton, and to determine the physico-chemical parameters in Situ Kenanga. The materials used in this study were sample water for nitrate and phosphate tests and phytoplankton samples from Situ Kenanga. Sampling was carried out from October 2020 to January 2021 during the rainy season, because environmental conditions in the waters depended on the season. Sampling was carried out for 3 weeks at 3 different stations. Each station consists of 3 points. Tests for nitrate and phosphate content as well as phytoplankton count were carried out in the laboratory. The results showed that the nitrate content in Situ Kenanga ranged from 2.29 mg/L - 3.89 mg/L. The nitrate content is classified as good so that it is optimal for the growth of phytoplankton. Phosphate content ranges from 0.3 mg/L - 0.5 mg/L. The phosphate content is relatively high but can still be tolerated by phytoplankton. The abundance of phytoplankton in Situ Kenanga ranged from 303.05 Cells/L – 727.65 Cells/L. There is a very strong relationship between the content of nitrate and phosphate with the abundance of phytoplankton in Situ Kenanga (r = 0.99)."

"ABSTRAKPenelitian torrefaksi bonggol jagung telah dilakukan untuk mempelajari pengaruh laju alir nitrogen terhadap yield dan komposisi bonggol jagung yang dihasilkan melalui proses torrefaksi. Pengaruh laju alir nitrogen diteliti dengan memvariasikan laju alir nitrogen sebesar 0,3 L/min, 0,5 L/min, dan 0,7 L/min dengan masing-masing variasi laju alir nitrogen dilakukan pada 3 variasi suhu torrefaksi, yaitu 250oC, 275oC, dan 300oC. Proses torrefaksi berlangsung di reaktor tubular dengan holding time 20 menit, heating rate 10oC/menit, dan total massa umpan 15 gram. Identifikasi pengaruh laju alir nitrogen dilakukan dengan menganalisis bonggol jagung hasil torrefaksi dengan menggunakan karakterisasi FTIR, Ultimate, dan Thermogravimetri Analysis (TGA). Hasil penelitian ini menunjukkan bahwa terdapat pengaruh laju alir nitrogen terhadap yield dan komposisi bonggol jagung hasil torrefaksi. Semakin besar laju alir nitrogen maka yield dari bonggol jagung hasil torrefaksi akan semakin kecil. Semakin besar laju alir nitrogen, kandungan oksigen dalam bonggol jagung hasil torrefaksi akan semakin berkurang dan kandungan karbonnya meningkat. Kandungan oksigen setelah torrefaksi menurun hingga 38% pada saat suhu torrefaksi 300oC dengan laju alir nitrogen sebesar 0,7 L/min sementara kandungan karbonnya meningkat hingga 44% bila dibandingkan dengan bonggol jagung umpan torrefaksi, rasio C/O meningkat dari 0,95 menjadi 2,19 dan rasio C/H meningkat dari 6,9 menjadi 13,99. Berdasarkan karakterisasi FTIR seiring semakin besar laju alir nitrogen maka gugus fungsi fenol, guaiacol, catechol, dan ether akan semakin tinggi. Data karakterisasi TGA menunjukan bahwa laju alir nitrogen tidak berpengaruh terhadap suhu pirolisis dari bonggol jagung yang sudah ditorrefaksi. Suhu torrefaksi adalah faktor yang mempengaruhi dari suhu pirolisis bonggol jagung yang sudah ditorrefaksi.

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ABSTRACTTorrefaction of corn cobs has been carried out to study the effect of nitrogen flow rate on yield and torrefied corn cobs composition produced through torrefaction. The effect of nitrogen flow rate was investigated by varying the nitrogen flow rate by 0,3 L/min, 0,5 L/min, and 0,7 L/min with each nitrogen flow rate variation performed on 3 torrefaction temperature variations are 250oC, 275oC, and 300oC. Torrefaction process takes place in a tubular reactor with a holding time of 20 minutes, a heating rate of 10oC/ minute, and a total feed mass of 15 grams. Identification of the effect of nitrogen flow rate was carried out by analyzing the torrefaction corn cobs using FTIR, Ultimate, and Thermogravimetric Analysis (TGA) characterizations. The results of this study indicate that nitrogen flow rate affects yield and torrefied corncobs composition. The greater the nitrogen flow rate, the lower is the yield of torrefied corn cobs. The greater the flow rate of nitrogen, the lower is the oxygen content in the corn cobs and the higher is the carbon content. The oxygen content after torrefaction decreased up to 38% when the torrefaction temperature was carried out at 300oC with a nitrogen flow rate of 0.7 L/min while the carbon content increased by 44%, the C/O ratio increased from 0,95 to 2,19 and the C/H ratio increased from 6,9 to 13,99. Based on FTIR characterization, increasing nitrogen flow rate increases the functional groups furan, phenol, guaiacol, catechol, and ether. Based on the TGA characterization, the nitrogen flow rate did not affect the pyrolysis temperature of the torrefied corn cobs. Torrefaction temperature is a factor that influences the pyrolysis temperature of torrefied corn cobs."

"ABSTRAKC. Vulgaris dikenal sebagai makhluk hidup yang kaya kandungan lipid yang dapat dimanfaatkan sebagi sumber energi baru. Besarnya kandungan lipid pada C. vulgaris dipengaruhi oleh nutrien yang terdapat di dalam medium dan salah satunya adalah konsentrasi nitrogen dalam kultur media. Pada penelitian ini, akan digunakan medium Walne sebagai kultur media C. vulgaris dengan variasi konsentrasi nitrat sebesar 0,100 g/L, 0,075 g/L, dan 0,050 g/L. Setelah sampai pada masa pemanenan, dilakukan pengambilan biomassa dan dilakukan uji kandungan dan kadar kandungan essensial, lipid, protein, klorofil, serta beta karoten. Dalam konsentrasi nitrogen 0,100 g/L kepadatan sel mencapai 1,251 g/L, konsentrasi 0,075 g/L sebesar 0,642 g/L, dan konsentrasi 0,050 g/L sebesar 0,636 g/L. Adapun kandungan lipid C. vulgaris dari konsentrasi nitrat0,100 g/L sebesar 14,08%, dalam konsentrasi 0,075 g/L sebesar 46,92% dan dalam konsentrasi 0,050 g/L mencapai 68,08%.

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Abstract

C. Vulgaris is known as a living creature that is rich in lipid content in which can be used as new energy sources. The amount of lipid content in C. vulgaris is affected by nutrients contained in the medium and one of them is the concentration of nitrogen in the culture media. In this study, will be used as culture Walne media as a culture media for C. vulgaris with the variation of nitrogen concentration of 0,100 g/L, 0,075 g/L, and 0,050 g/L. After arriving in the harvesting, done and done test shooting biomass content and levels of essential content, lipid, protein, chlorophyll and beta carotene. Nitrogen concentration in the 0,100 g/L, cell density reached 1,251 g/L, at concentration 0,075 g/L cell density reached 0,642 g/L, and at concentration 0,050 g/L cell density reached 0,636 g/L. The lipid content of C. vulgaris of the nitrogen concentration of 0,100 g/L at 14,08%, at concentration 0,075 g/L by 46,92% and at concentration of 0,050 g/L reached 68,08%."

"Tanaman dapat menyerap nitrogen secara efisien jika berbentuk nitrogen terfiksasi, seperti nitrat dan ammonia dalam pupuk. Air Plasma Electrolysis dapat dimanfaatkan dalam produksi pupuk nitrat cair dengan menggunakan bahan baku udara yang diinjeksikan melalui katoda menuju zona plasma. Penelitian ini bertujuan untuk memperoleh produk pupuk nitrat cair yang optimum dari prototipe alat produksi pupuk nitrat cair dengan injeksi udara di katoda dan mendapatkan kondisi operasinya. Penelitian ini dilakukan dalam reaktor batch, dengan variasi daya (400, 500, 600 Watt), laju alir udara (0; 0,4; 0,6; 0,8; 1; 1,2 lpm), jarak antara anoda (zona plasma) dengan injektor katoda (1 cm, 2 cm, 3 cm), variasi komposisi konsentrasi elektrolit (0,01 M K2HPO4/0,006 M K2SO4; 0,011 M K2HPO4/0,007 M K2SO4; 0,018 M K2HPO4/0,007 M K2SO4; 0,011 M K2HPO4/0,008 M K2SO4; dan 0,018 M K2HPO4/0,008 M K2SO4), suhu operasi (25 oC – 50 oC dan 50 oC), dan penambahan aditif Fe2+ (10 ppm, 20 ppm, 30 ppm). Produksi nitrat optimum sebesar 1727,2 ppm dengan energi spesifik sebesar 5,82 kJ/mmol, ketergerusan anoda sebesar 0,06 g, dalam waktu operasi 90 menit, pada daya 600 watt, laju alir udara 0,8 lpm, jarak antara anoda (zona plasma) dan injektor udara katoda sebesar 2 cm, menggunakan larutan elektrolit 0,007 M K₂SO₄ dan 0,011 M KH₂PO₄, dengan penambahan aditif ion Fe²⁺ sebesar 30 ppm, dan penggunaan elektroda Stainless Steel-316 (SS-316).

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Plants can efficiently absorb nitrogen when it is in a fixed form, such as nitrate and ammonia in fertilizers. Air Plasma Electrolysis can be utilized in the production of liquid nitrate fertilizer using air injected through the cathode into the plasma zone. This study aims to obtain an optimum liquid nitrate fertilizer product from a prototype nitrate fertilizer production device with air injection at the cathode and to determine its operating conditions. The research is conducted in a batch reactor, with variations in power (400, 500, 600 watts), air flow rate (0; 0.4; 0.6; 0.8; 1; 1.2 lpm), distance between the anode (plasma zone) and cathode injector (1 cm, 2 cm, 3 cm), electrolyte composition (0.01 M K2HPO4/0.006 M K2SO4; 0.011 M K2HPO4/0.007 M K2SO4; 0.018 M K2HPO4/0.007 M K2SO4; 0.011 M K2HPO4/0.008 M K2SO4; and 0.018 M K2HPO4/0.008 M K2SO4), operating temperature (25°C – 50°C and 50°C), and the addition of Fe²⁺ additive (10 ppm, 20 ppm, 30 ppm). The optimum nitrate production is 1727.2 ppm with a specific energy of 5.82 kJ/mmol, anode erosion of 0.06 g, within an operating time of 90 minutes, at a power of 600 watts, air flow rate of 0.8 lpm, a distance between the anode (plasma zone) and cathode air injector of 2 cm, using an electrolyte solution of 0.007 M K₂SO₄ and 0.011 M KH₂PO₄, with the addition of Fe²⁺ ion additive at 30 ppm, and using Stainless Steel-316 (SS-316) electrodes."

"Latar belakang: Penelitian terdahulu telah menunjukkan peran penting bakteri Rothiaspp. dalam keseimbangan mikrobioma oral. Mikrobioma oral yang seimbang berperanterhadap pencegahan berbagai penyakit rongga mulut. Namun, pengaruh pemberian nitratterhadap pertumbuhan bakteri tersebut masih belum sepenuhnya dipahami, terutama padakelompok individu yang memiliki kebiasaan merokok. Merokok dapat mengubahkomposisi mikrobiota oral dan memengaruhi metabolisme bakteri, sehingga pentinguntuk menyelidiki bagaimana pajanan nitrat dapat memodulasi pertumbuhan bakteri inidalam konteks tersebut. Dasar dilakukannya penelitian ini adalah untuk mengeksplorasipotensi pajanan nitrat yang berasal dari sayur-sayuran dalam meningkatkan jumlahbakteri pereduksi nitrat pada biofilm saliva subjek perokok usia dewasa muda.Tujuan:Melihat potensi nitrat larutan daun arugula dalam meningkatkan pertumbuhan bakteriRothia spp. pda perokok usia dewasa muda. Metode: Sampel saliva hasil poolingdikelompokkan berdasarkan pH supernatant saliva dan kebiasaan merokok. Kemudian,sampel diberikan pajanan larutan daun arugula dengan konsentrasi nitrat berbeda (6,25μM dan 3,25 μM) dan durasi pajanan berbeda (5 dan 9 jam) untuk melihat perubahanterhadap pH supernatant saliva, kadar nitrit saliva dan jumlah bakteri Rothia spp.Pengukuran pH supernatant saliva dilakukan menggunakan kertas strip pH. Pengujiankadar nitrit saliva dilakukan dengan uji griess pada sampel yang merepresentasikan kadarnitratnya. Metode Total Plate Count digunakan untuk menghitung jumlah bakteri Rothiaspp. yang tumbuh pada medium spesifik. Untuk memastikan benar bakteri Rothia spp. yang tumbuh, dilakukan pewarnaan gram dan PCR konvensional dengan primer Rothia. Hasil: Tidak terdapat perbedaan yang signifikan antara pajanan larutan daun arugula terhadap kadar nitrit saliva dan jumlah bakteri Rothia spp. Terdapat pola peningkatan kadar nitrit saliva berdasarkan durasi pajanan dengan hasil yang berbanding lurus dengan jumlah bakteri Rothia spp. Kesimpulan: Hasil penelitian menunjukkan pajanan larutan daun arugula mampu mempertahankan dan mengurangi asidifikasi pH supernatant saliva. Secara umum, potensi nitrat asal daun arugula konsentrasi 3,25 μM memiliki potensi yang lebih tinggi dibandingkan dengan nitrat asal daun arugula konsentrasi 6,25 μM dalam meningkatkan pertumbuhan bakteri Rothia spp.

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Background:Previous research has shown the important role of Rothia spp. in maintaining the balance of oral microbiome. A balanced oral microbiome plays a crucial role in preventing various oral diseases. However, the effects of nitrate administration on the growth of these bacteria are not fully understood, especially in individuals who smoke. Smoking can alter the composition of oral microbiota and affect bacterial metabolism, making it important to investigate how nitrate exposure can modulate the growth of these bacteria. The basis of this research is to explore the potential of nitrate exposure derived from vegetables in increasing the number of nitrate-reducing bacteria in the salivary biofilm of young adult smokers. Objectives: The objective of this study is to investigate the potential of nitrate originating from arugula leaves in increasing the number of Rothia spp. bacteria in young adult smokers. Methods: Saliva samples were pooled based on supernatant pH and smoking habit. The samples were then exposed to arugula leaf solution with different nitrate concentration (6,25 μM dan 3,25 μM) and different exposure durations (5 and 9 hours) to observe changes in supernatant pH, nitrite levels, and the viability of Rothia spp. bacteria. Supenatant pH was measured using pH strips. The nitrite levels in saliva were tested using the Griess assay. The total plate count method was used to calculate the viability of Rothia spp.bacteria growing on specific media. To confirm that the bacteria growing were indeed Rothia spp., gram staining and conventional PCR with Rothia primers were performed. Results: There is no significant difference between the exposure of arugula leaf solution regarding the level of nitrite in saliva and the viability of Rothia spp. This study shows a pattern of increased nitrite levels in saliva according to the duration of exposure, which are linear with the viablity of Rothia spp. Conclusion: The results of the study indicate that exposure to arugula leaf solution can maintain and reduce the acidification of supenatant pH. In general, the nitrate potential of arugula leaves at a concentration of 3,25 μM has a higher potential compared to the nitrate potential of arugula leaves at a concentration of 6,25 μM in enhancing the growth of Rothia spp. bacteria."

"Nitrogen adalah unsur terpenting bagi tanaman untuk hidup, dan hanya dapat diserap oleh tanaman dalam bentuk yang lebih sederhana, yaitu nitrat. Elektrolisis Plasma adalah teknologi untuk sintesis material baru yang spesies reaktif seperti radikal hidroksil yang dapat menginisiasi berbagai reaksi, termasuk reaksi fiksasi nitrogen dari udara menjadi pupuk cair nitrat, yang merupakan pupuk cair untuk tanaman. Penelitian ini bertujuan untuk mengetahui bagaimana nitrat dapat dibentuk melalui proses Elektrolisis Plasma dan pengaruh konsentrasi elektrolit, laju alir udara, dan efek penambahan ion Fe2+. Penelitian ini dilakukan pada reaktor batch menggunakan elektrolit K2SO4 dengan konsentrasi 0,01 M; 0,02 M; 0,04 M, laju alir udara 0,1 lpm; 0,2 lpm; 0,8 lpm, dan penambahan 50 ppm ion Fe2+. Proses dilakukan pada daya optimal yang diperoleh dari hasil karakterisasi arus-tegangan. Konsentrasi nitrat yang terbentuk diuji secara kuantitatif menggunakan metode spektrofotometri UV-Vis. Hasil penelitian ini menunjukkan bahwa semakin besar konsentrasi elektrolit dan semakin besar laju alir udara akan meningkatkan produktivitas nitrat. Sementara itu penambahan ion Fe2+ membuat nitrat yang dihasilkan berkurang. Konsumsi energi spesifik yang diperlukan dari setiap variasi berkurang seiring dengan meningkatnya jumlah nitrat. Nitrat tertinggi yang terbentuk adalah 636,8 ppm pada konsentrasi 0,02 M K2SO4, laju alir udara 0,8 lpm, tanpa penambahan ion Fe2+. Konsumsi energi spesifiknya adalah 35,06 kJ/mmol. Hasil ini menunjukkan bahwa nitrat dapat diproduksi secara efektif dengan metode Elektrolisis Plasma.

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Nitrogen is the important element for plants to live, and it just can be absorbed by plants in the simpler compounds form, which is nitrate. Contact Glow Discharge Electrolysis (CGDE) is a technology for the synthesis of new materials with the reactive species such as hydroxyl radicals are produced, including fixation of nitrogen from the air into nitrate solutions, which is the liquid fertilizer for plants.

This research aims to determine how the nitrate can be formed through CGDE process and the influence of potassium sulfate concentration, air flow rate, and the Fe2+ ion effect. This research was conducted in a batch reactor using K2SO4 electrolyte with a concentration of 0.01 M; 0.02 M; 0.04 M. air flow rate of 0,1 lpm; 0,2 lpm; 0,8 lpm, and the adding of 50 ppm Fe2+. The process is carried out at optimum power obtained from the results of plasma electrolysis current-voltage characterization. The concentration of nitrate formed was tested quantitatively using the UV-Vis spectrophotometry method.

The results of this research show that the greater the concentration of electrolytes and the greater air flow rate increase the nitrate productivity. Meanwhile the adding Fe2+ make the nitrate produced decrease. The specific energy consumption needed of each variation is decrease with the increase of nitrate amount. Highest nitrate formed is 636,8 ppm at 0,02 M K2SO4 concentration, 0,8 lpm air flow rate, without adding the Fe2+. Its specific energy consumption is 35,06 kJ/mmol. These results indicate that nitrates can be produced effectively by the CGDE method."

"Senyawa pirimidin merupakan senyawa heterosiklik bahan alam yang memiliki bioaktivitas seperti penghambat kanal kalsium, antimikroba, antivirus, antioksidan, dan antikanker. Senyawa turunan pirimidin dapat disintesis melalui reaksi Biginelli yang termasuk reaksi multikomponen. Reaksi ini dapat dilakukan pada suhu ruang dalam satu wadah dengan menggunakan prekursor tiourea, etil asetoasetat, dan aldehida aromatik. Pada penelitian ini, dilakukan sintesis senyawa turunan pirimidin dengan bantuan katalis organik L-prolin nitrat. Katalis L-prolin nitrat dapat meningkatkan efisiensi waktu dan meningkatkan yield hasil sintesis. Hasil sintesis senyawa pirimidin optimal dilakukan pada kondisi penggunakan katalis sebesar 10% mol dan menggunakan pelarut metanol. Hasil sintesis didapatkan berupa senyawa 1 dengan %yield sebesar 86,74%, senyawa 2 sebesar 87,93%, dan senyawa 3 sebesar 84,80%. Produk hasil sintesis dan katalis L-prolin nitrat dikonfirmasi dengan menggunakan intrumen KLT, FT-IR, spektrofotometer

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Pyrimidine is a natural heterocyclic compound which has bioactivities such as calcium channel blocker, antibacterial, antivirus, antioxidant, and anticancer. Pyrimidine derivatives can be synthesized using Biginelli reaction which classified as a multicomponent reaction. This reaction can be undergone in room temperature in one pot using thiourea, ethyl acetoacetate, and aromatic aldehyde as the precursors. Synthesis of pyrimidine derivatives using L-proline nitrate as organocatalyst has been conducted, which was elevating time efficiency and elevating yield of the products on the system of the reaction. The optimum results could be achieved at 10 mol % using methanol as a solvent. The % yield of the compound  1, 2, and 3 are 86.74%, 87.93%, and 84.80%, respectively. The results of the Biginelli reaction and the L-proline nitrate have been confirmed using TLC, FT-IR spectrometer, UV-Vis spectrometer, and GC-MS."

"Characterizations have been performed on single stage Transversely Excited Nitrogen Laser of Blumlein type. Optical cavity arrangement is varied prior to measurement which shows no significant increase in energy on both configurations of inserting a mirror only and a pair of mirror and a quartz parallel plate. Frequency repetitions respond reveals a small drop in energy at higher frequency i.e. 10 Hz by a factor of 20%. N2 flow rate consideration behaves on the similar way like pressure profile. At higher supply voltage maximum energy is shifted to higher N2 flow rate. A similar tendency occurs on pressure curve but with more pronounced maximum energy. Higher supply voltage would shift maximum energy to higher N2 pressure. Other operating conditions have been kept constant. Beam divergence measurement has given 1,87 mrad on vertical direction and 9,32 mrad on horizontal axis. However, beam cross section experiences a -10° tilt against horizontal reference. This may happen due to a slight twist on main electrodes. Measurements on different date have showed inconsistent results. Major cause is suspected on using different N2 cylinder, replacement on the gauge pressure, and crater creation on HV side spark gap electrode."

"ABSTRAKDenitrifikasi merupakan proses perubahan bentuk nitrat menjadi gas nitrogen. Proses tersebut umumnya dilakukan oleh bakteri dalam kondisi lingkungan dengan konsentrasi nitrat tinggi dan rendah oksigen. Isolat CD I-III telah diisolasi dari sungai Cideng, Jakarta, diketahui memiliki kemampuan denitrifikasi. Optimasi terhadap aktivitas denitrifikasi dilakukan dengan menumbuhkan isolat dalam medium Nitrate Broth dengan variasi sumber karbon glukosa dan gliserol selama 19 hari. Parameter uji aktivitas denitrifikasi dilakukan dengan perhitungan konsentrasi nitrat dan nitrit menggunakan metode kolorimetri dan perhitungan jumlah bakteri dengan metode Total Plate Count. Identifikasi isolat CD I-III dilakukan menggunakan VITEK-2. Hasil penelitian menunjukkan bahwa penambahan sumber karbon glukosa dan gliserol memberikan perbedaan signifikan pada = 0,05 terhadap perubahan konsentrasi nitrat dan nitrit namun tidak pada jumlah bakteri. Isolat CD I-III berhasil diidentifikasi menggunakan VITEK-2 sebagai Escherichia hermannii dengan tingkat probabilitas 97.

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ABSTRACTDenitrification is reducing processes of nitrate into nitrogen gases. Bacteria is able to do this process in high nitrate and low oxygen concentration. Isolate CD I III isolated from Cideng river, Jakarta, is known to have the denitrification ability. Isolate was inoculated in Nitrate Broth medium with carbon source variations for 19 days to optimize denitrification activity. Parameters used to measure the denitrification activity are nitrate and nitrite concentration by colorimetric method and bacterial viability by total plate count method. Isolate was also identified by using VITEK 2. The result revealed that glucose and glycerol as carbon source variations gave a significant difference 0,05 in nitrate and nitrite concentration whilst no difference in bacterial viability. Isolate CD I III was identified by VITEK 2 as Escherichia hermannii with 97 probability."