scholarly journals Effect of CO2 Flow Rate and Carbonation Temperature in the Synthesis of Crystalline Precipitated Calcium Carbonate (PCC) from Limestone

2018 ◽  
Vol 18 (4) ◽  
pp. 573 ◽  
Author(s):  
Sri Wardhani ◽  
Fanny Prasetia ◽  
Mohammad Misbah Khunur ◽  
Danar Purwonugroho ◽  
Yuniar Ponco Prananto
Keyword(s):  
Flow Rate ◽  
Particle Diameter ◽  
Ammonia Solution ◽  
Powder Xrd ◽  
Low Flow ◽  
High Yield ◽  
Precipitated Calcium Carbonate ◽  
Optimum Flow Rate ◽  
Carbonation Process ◽  
Optimum Flow

The effect of CO2 flow rate and carbonation temperature were studied in the synthesis of PCC from limestone using carbonation method. The synthesis was started by dissolving CaO that was obtained from calcination of limestone into HNO3 6M. The solution was then added with ammonia solution and then streamed with CO2 until pH 8 with flow rates of 0.5; 1.0; 1.5; and 2.0 L/min. The optimum flow rate obtained from this stage was then applied in the carbonation process with temperatures of 50, 80, 100, 150, 200, and 250 °C. The results showed that low flow rate give reasonably high yield but the yields obtained in every flow rate used in this work has insignificant difference based on F-test. The optimum flow rate used for the synthesis of PCC in the next stage was 0.5 L/min with a yield of 62.95%. Different carbonation temperature influences the polymorphs and crystallinity of the synthesized PCC. The synthesized PCC was analyzed by FT-IT, powder-XRD, SEM-EDX, and PSA. FT-IR analysis showed stretching vibrations of C–O at 1419, 1479, and 1384 cm-1 which correspond to calcite, vaterite, and aragonite respectively. Powder-XRD and SEM-EDX confirms that at the carbonation temperature of 50 °C, calcite and vaterite were formed, while at the carbonation temperature of 80 °C, mixture of calcite-vaterite-aragonite were obtained. Higher carbonation temperature changes the vaterite and aragonite polymorphs into calcite, and the best crystallinity was obtained at 250 °C. PSA analysis showed that the particle diameter of the synthesized PCC was about 3.58 to 38.14 µm.

scholarly journals Head lettuce production and nutrition in relation to nutrient solution flow

2020 ◽  
Vol 38 (1) ◽  
pp. 21-26
Author(s):  
Cleiton Dalastra ◽  
Marcelo CM Teixeira Filho ◽  
Marcelo R da Silva ◽  
Thiago AR Nogueira ◽  
Guilherme Carlos Fernandes
Keyword(s):  
Nutrient Solution ◽  
Flow Rate ◽  
Nutrient Accumulation ◽  
Solution Flow ◽  
Flow Rates ◽  
Hydroponic System ◽  
Optimum Flow Rate ◽  
Technical Performance ◽  
Use Efficiency ◽  
Optimum Flow

ABSTRACT The optimum flow rate of nutrient solution in hydroponic system can better nourish the crops, allowing healthy and faster growth of lettuce. However, flow also interferes with electric power consumption, so further researches are necessary, mainly on the effect of flow rate, nutrient accumulation and lettuce production. In this context, the aim of this study was to evaluate nutrition and production of head lettuce in relation to the nutrient solution flow in NFT hydroponic system. The treatments consisted of nutrient solution application at the flow rates 0.5; 1; 2, and 4 liters per minute in each cultivation channel. Five replicates per treatment consisted of 15 plants each. The flow in hydroponic systems to produce head lettuce alters the technical performance of the crop. Due to the greater nutrient accumulation in shoot and use efficiency of these elements, the highest production (g/plant) of head lettuce was obtained with a flow rate of 1 L/min of the nutrient solution.

THE RAPID DETERMINATION OF LOW CONCENTRATIONS OF CARBON MONOXIDE IN AIR

1948 ◽  
Vol 26f (8) ◽  
pp. 318-330 ◽  
Author(s):  
Morris Katz ◽  
John Katzman
Keyword(s):  
Carbon Monoxide ◽  
Flow Rate ◽  
Rapid Determination ◽  
Major Change ◽  
Space Velocity ◽  
Optimum Flow Rate ◽  
Low Concentrations ◽  
High Space ◽  
Optimum Flow

A granular form of silver permanganate on a zinc oxide carrier has been found to oxidize carbon monoxide in air at ordinary temperatures and at high space velocities. There is no noticeable change in activity over the range of 30 to 100% relative humidity of the air, although a small amount of water vapor is essential to initiate the combustion of carbon monoxide. The above properties have been utilized in the rapid determination of low concentrations by measuring the heat of oxidation in a thermocouple cell. The relation between the potential of the thermocouple junctions and the concentration of carbon monoxide is linear over the range of 0 to 600 p.p.m. at a definite space velocity. With increasing flow rate at a constant concentration the potential rises rapidly to a maximum, but in the range of optimum flow the flow rate may be varied considerably without producing a major change in e.m.f. The thermal efficiency is about 81% at the optimum flow rate. Hydrogen, unless it is present in amounts considerably in excess of the carbon monoxide concentration, does not introduce an appreciable error in the determination. The method is applicable to the field determination of considerably less than 0.005% carbon monoxide in air and the degree of precision is about equal to that of most laboratory methods. Twenty to twenty-five cubic centimeters of the material will give a useful life of over eight hours in continuous tests on concentrations below 0.1% carbon monoxide.

Experimental study on the optimum flow rate and pressure for selective cerebral perfusion

1995 ◽  
Vol 59 (3) ◽  
pp. 651-657 ◽  
Author(s):  
Hisashi Tanaka ◽  
Teruhisa Kazui ◽  
Hiroki Sato ◽  
Norio Inoue ◽  
Osamu Yamada ◽  
...  
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Cerebral Perfusion ◽  
Selective Cerebral Perfusion ◽  
Optimum Flow Rate ◽  
Optimum Flow

scholarly journals PENINGKATAN KUALITAS EFLUEN LIMBAH CAIR INDUSTRI TAHU PADA SISTEM LUMPUR AKTIF DENGAN VARIASI LAJU ALIR MENGGUNAKAN ARANG AKTIF KAYU ULIN (Eusideroxylon zwageri)

2016 ◽  
Vol 12 (3) ◽  
pp. 207
Author(s):  
Filomena Matilda ◽  
Danang Biyatmoko ◽  
Akhmad Rizali ◽  
Abdullah Abdullah
Keyword(s):  
Activated Sludge ◽  
Surface Area ◽  
Flow Rate ◽  
Activated Charcoal ◽  
Wastewater Effluent ◽  
Adsorption Method ◽  
Optimum Flow Rate ◽  
Alternative Processing ◽  
Optimum Flow

Tofu industry produces organic waste that can decrease the quality of the environment. The alternative processing method can be used among others is activated sludge system, but several types of research have not shown optimal results yet. To improve the quality of wastewater, the treatment of wastewater of tofu using activated charcoal needs to be done. The purpose of this research is to analyze the effects of the ironwood charcoal activation on the morphology and surface area of  ironwood activated charcoal, to analyze the effects of variations in the flow rate of tofu wastewater effluent from activated sludge using ironwood activated charcoal on the parameters of temperature, pH, TSS, BOD, COD and ammonia and to find out the optimum flow rate of tofu wastewater effluent from activated sludge using ironwood activated charcoal. This research used adsorption method with column system at 7 treatments of flow rate (50, 60, 70, 80, 90, 100 and 110 mL/h) with 3 replications. The activation of ironwood charcoal used Na2CO3 5% and was activated at 400oC. The results showed that the surface morphology of ironwood active charcoal had more open pore surfaces with more regular structures than before activation. The surface area of ironwood activated charcoal was 32.936 m2/g and increased to 53.7% compared with it before activation. Variations in the flow rate on the tofu wastewater effluent from activated sludge using ironwood activated charcoal showed highly significant (p < 0.01) in reducing the levels of TSS, BOD, COD, and ammonia. The optimum flow rate obtained at 50 mL/h with temperature was 25.8oC, pH 8.08, TSS 34.7 mg/L, BOD 43.8 mg/L, COD 117 mg/L and ammonia 14.8 mg/L. The value of temperature, pH, TSS and BOD have fulfilled the quality standards, the quality of tofu wastewater effluent increased from the activated sludge.

scholarly journals Optimasi Efisiensi Kolom dalam Kromatografi Menggunakan Visual Basic 2008

2012 ◽  
Vol 12 (1) ◽  
pp. 13
Author(s):  
Harry S.J Koleangan
Keyword(s):  
Flow Rate ◽  
Secondary Data ◽  
Visual Basic ◽  
Column Efficiency ◽  
Optimum Flow Rate ◽  
Optimization Parameters ◽  
Gauss Elimination ◽  
Optimum Flow ◽  
Gauss Elimination Method ◽  
Van Deemter Equation

OPTIMASI EFISIENSI KOLOM  DALAM KROMATOGRAFI MENGGUNAKAN VISUAL BASIC 2008 ABSTRAK Telah dibuat sebuah program aplikasi yang ditujukan untuk optimasi efisiensi kolom yang digunakan dalam pemisahan secara kromatografi. Parameter-parameter untuk optimasi ini dianalisis menggunakan metode eliminasi Gauss dalam bentuk program komputer yang ditulis menggunakan bahasa pemrograman Visual Basic 2008 Express Edition. Penggunaan program ini terhadap suatu data sekunder memberikan hasil efisiensi kolom optimum, yang dinyatakan sebagai tinggi plat teoritis (H) terkecil, sebesar 0,0223 cm yang dicapai pada laju alir optimum 20,6 cm/det. Kata kunci: Efisiensi kolom, eliminasi Gauss, persamaan van Deemter, Visual Basic 2008   OPTIMIZATION OF COLUMN EFFICIENY IN CHROMATOGRAPHY USING VISUAL BASIC 2008 ABSTRACT An application program to optimize  column efficiency in chromatographic separation had been developed. Optimization parameters were analyzed using Gauss elimination method which was written in the form of a computer program using Visual Basic 2008 Express Edition programming language. Application of the program on the secondary data gave the optimum column efficiency, which was represented as height equivalent to a theoritical plate (H), of 0,0223 cm which was achieved at optimum flow rate of 20,6 cm/det Keywords: Column efficiency, Gauss elimination, van Deemter equation, Visual Basic 2008

scholarly journals TITANIUM DIOXIDE SUSPENSION PHOTOCATALYSIS IN A TUBULAR PHOTOREACTOR AND TITANIUM DIOXIDE REUSE ON THE REMOVAL OF PHENOL

2018 ◽  
Vol 4 (2) ◽  
Author(s):  
Dhanus Suryaman
Keyword(s):  
Titanium Dioxide ◽  
Flow Rate ◽  
Tap Water ◽  
Deionized Water ◽  
Degradation Efficiency ◽  
Low Flow ◽  
Single Pass ◽  
Flow Treatment ◽  
Optimum Flow ◽  
Dioxide Suspension

We studied flow rate, electrolytes effects, titanium dioxide separation and reuse and sunlight application on photocatalysis in a tubular photoreactor integrated with the titanium dioxide separation/reuse. The circulative flow treatment was preferred over the single pass treatment. Phenol and TOC removals in tap and deionized waters were a maximum at the circulative flow rate of 600 ml min-1 and the transmittance of 0.26%. At low flow rate, titanium dioxide particles were sedimented in tap water, but those were perfectly suspended in deionized water. The titanium dioxide slurry was sedimented spontaneously by standing and was repeatedly reused without decreasing the degradation efficiency.  Keywords : Photocatalytic, Optimum flow, Electrolytes, Separation, Solra 

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