scholarly journals Study of Nitrobenzene Kinetic Particularities over Ni-containing Hypercrosslinked Polystyrene

2020 ◽  
Vol 6 (4) ◽  
pp. 18-26
Author(s):  
L. Mushinskii ◽  
I. Navrotskaya ◽  
R. Brovko ◽  
V. Doluda
Keyword(s):  
Maximum Yield ◽  
Preexponential Factor ◽  
Hydrogenation Reaction ◽  
Linear Increase ◽  
Effect Of Temperature ◽  
Maximum Speed ◽  
Transformation Rate ◽  
Nitrobenzene Hydrogenation ◽  
Multi Stage ◽  
Optimal Area

This paper presents a study of the kinetics of catalytic hydrogenation of nitrobenzene to aniline in the presence of Ni-containing catalysts based on super-crosslinked polystyrene. Aniline hydrogenation is a complex multi-stage process accompanied by the formation of a large number of both intermediate and by-products, including azobenzene, azoxybenzene, nitrosobenzene, phenylhydroxylamine and other substances. Therefor the study of the process kinetics is an important scientific and technical task necessary to increase the yield of the target product — aniline. The hydrogenation reaction of nitrobenzene was carried out in a six-cell high-pressure reactor Parr instruments, Series 5000. The products were analyzed by chromatography using a gas chromatograph Kristallux-4000M (Russia, Meta–Chrom). The effect of temperature, pressure, and concentration of the catalyst was studied; optimal reaction conditions were selected that ensure the maximum yield of aniline. Investigation of the effect of the nitrobenzene initial concentration on the rate of its transformation shows that increase of catalyst to nitrobenzene ratio from 0.2 to 0.6 kg (Cat)/kg (NB) leads to a linear increase in the rate of transformation of nitrobenzene from 0.0002 kg (NB) / (kg (Cat)*s ) to 0.0028 kg(NB)/(kg(Cat)*s), a further increase in the ratio of catalyst concentration to nitrobenzene concentration to 1.2 kg (Cat)/kg(NB) leads to stabilization of the nitrobenzene transformation rate at the level of 0.003 kg(NB)/(kg(Cat)*s). An increase in the temperature of the reaction from 90 to 160 °C contributes to a significant increase in the nitrobenzene transformation rate. The constructed dependences made it possible to calculate the apparent activation energy of the process, which amounted to be 50.4 kJ/mol and the preexponential factor, which amounted to be 15821.1 1/s. The applicability of the Langmuir–Henschelwood model to describe the basic kinetic laws of the reaction of catalytic nitrobenzene hydrogenation with the formation of aniline is studied. Numerical methods in the Matlab software allows to determine the values of preexponential factors and activation energies of the nitrobenzene hydrogenation processes, adsorption of nitrobenzene and adsorption of hydrogen, which made it possible to establish the optimal area of nitrobenzene hydrogenation process of hydrogenation of Pн2 = 15–18 atm, C(NB) = 1.2 kg(NB)/kg(Cat), t =115–120 °C providing maximum speed.

scholarly journals Studies on Effect of Temperature on Asphaltene precipitation using Multi Stage Extraction

2017 ◽  
Vol 7 (1.1) ◽  
pp. 599
Author(s):  
Kethineni Chandrika ◽  
N Sampath ◽  
Jobin V J ◽  
E Seetha Ramaiah ◽  
Vishnu Vipin ◽  
...  
Keyword(s):  
Good Yield ◽  
Maximum Yield ◽  
Extraction Process ◽  
Extraction Time ◽  
Effect Of Temperature ◽  
Solvent Ratio ◽  
Multistage Process ◽  
Asphaltene Precipitation ◽  
Extraction Percentage ◽  
Multi Stage

In the case of asphaltene extraction, single stage extraction given a maximum yield at 30°c with the sample to solvent ratio of 1:25. The time taken for the extraction process is 24 hours. In the case of long step extraction process its sample to ratio is 1:4. When the temperature increased in the process the yield also started increasing. The maximum yield we could get in the temperature range of 30°c to 50°c. It is possible to reduce the extraction time by increasing the temperature and it gives a good yield of asphaltene with the usage of multistage process. It increased the asphaltene presence about 69% in the solvent. The asphaltene yield at 30°c give raise an extraction of 85% in a six-stage extraction process. It is possible to get the same extraction percentage in a temperature of 50°c with three stage extraction process.  

Dealing with hot rocky environments: Critical thermal maxima and locomotor performance in Leptodactylus lithonaetes (Anura: Leptodactylidae)

2019 ◽  
pp. 155-161 ◽  
Author(s):  
Ivan Beltran
Keyword(s):  
Environmental Temperature ◽  
Extreme Temperature ◽  
Effect Of Temperature ◽  
Maximum Speed ◽  
Locomotor Performance ◽  
Extreme Temperatures ◽  
Physiological Limits ◽  
Fitness Consequences ◽  
Thermal Maximum ◽  
Environmental Temperatures

Environmental temperature has fitness consequences on ectotherm development, ecology and behaviour. Amphibians are especially vulnerable because thermoregulation often trades with appropriate water balance. Although substantial research has evaluated the effect of temperature in amphibian locomotion and physiological limits, there is little information about amphibians living under extreme temperature conditions. Leptodactylus lithonaetes is a frog allegedly specialised to forage and breed on dark granitic outcrops and associated puddles, which reach environmental temperatures well above 40 ˚C. Adults can select thermally favourable microhabitats during the day while tadpoles are constrained to rock puddles and associated temperature fluctuations; we thus established microhabitat temperatures and tested whether the critical thermal maximum (CTmax) of L. lithonaetes is higher in tadpoles compared to adults. In addition, we evaluated the effect of water temperature on locomotor performance of tadpoles. Contrary to our expectations, puddle temperatures were comparable and even lower than those temperatures measured in the microhabitats used by adults in the daytime. Nonetheless, the CTmax was 42.3 ˚C for tadpoles and 39.7 ˚C for adults. Regarding locomotor performance, maximum speed and maximum distance travelled by tadpoles peaked around 34 ˚C, approximately 1 ˚C below the maximum puddle temperatures registered in the puddles. In conclusion, L. lithonaetes tadpoles have a higher CTmax compared to adults, suggesting a longer exposure to extreme temperatures that lead to maintain their physiological performance at high temperatures. We suggest that these conditions are adaptations to face the strong selection forces driven by this granitic habitat.

scholarly journals Spatial arrangement of maize plants aiming to maximize grain yield in the hybrid BRS-3046

2020 ◽  
pp. 1662-1669
Author(s):  
Marcus Willame Lopes Carvalho ◽  
Edson Alves Bastos ◽  
Milton José Cardoso ◽  
Aderson Soares de Andrade Junior ◽  
Carlos Antônio Ferreira de Sousa
Keyword(s):  
Grain Yield ◽  
Plant Density ◽  
Intercellular Co2 Concentration ◽  
Maximum Yield ◽  
Co2 Concentration ◽  
Spatial Arrangement ◽  
Co2 Assimilation ◽  
Linear Increase ◽  
Planting Density ◽  
Row Spacing

The objectives of this study were to: (i) evaluate the effect of different spatial arrangements on morpho-physiological characteristics and (ii) determine the optimal spatial arrangement to maximize grain yield of the maize hybrid BRS-3046 grown in the Mid-North region of Brazil. We tested two row spacings (0.5 and 1 m) and five plant densities (2, 4, 6, 8, 10 plants m-2), which corresponded to 10 different plant spatial arrangements. Different morphophysiological variables, gas exchange rates and grain yield were measured. The increased planting density led to a linear increase in LAI, regardless of row spacing, while the net CO2 assimilation rate increased until the density of 4 and 6 plants m-2, under a row spacing of 0.5 and 1.0 m, respectively. On the other hand, we found a linear reduction in the stomatal conductance with increasing planting density. The intercellular CO2 concentration and the transpiration rate were higher in the widest row spacing. The instantaneous efficiency of carboxylation, in turn, showed a slight increase up to the density of six plants m-2, then falling, regardless of row spacing. Increasing plant density resulted in a linear increase in plant height and ear insertion height, regardless of row spacing. However, it had an opposite effect on stem diameter. Grain yield, in turn, increased up to 7.3 plants m-2 at a row spacing of 0.5 m and 8 plants m-2 at a row spacing of 1.0 m. This spatial arrangement was considered as ideal for achieving maximum yield

Demonstration and Characterization of a Multi-Stage Silicon Microturbine

2005 ◽  
Author(s):  
Changgu Lee ◽  
Luc G. Fre´chette
Keyword(s):  
Layer Structure ◽  
Experimental Testing ◽  
Maximum Speed ◽  
Glass Wafer ◽  
Multi Stage ◽  
Calculation Results ◽  
Etched Silicon ◽  
Radial Outflow ◽  
Isentropic Efficiency

This paper presents the experimental testing and characterization of a microscale radial outflow turbine with four concentric stages. The device is a five layer structure composed of shallow and deep reactive ion etched silicon wafers and an ultrasonically drilled Pyrex glass wafer that are assembled using anodic and fusion bonding techniques. They enclose a 4mm diameter rotor that was spun up to 330,000 rpm and produced roughly 0.1W of mechanical power from each stage totaling 0.38W with 0.75 atm differential pressure across the microturbine. Modeling of the turbine based on a mean line analysis with loss correlations extracted from CFD suggests a turbine isentropic efficiency of 35% and Re=266 at the maximum speed. The pressure distribution across the blades rows was measured and showed close agreement with the calculation results. Using the model, the microturbine is predicted to produce 3.2 watts with an isentropic efficiency of 63% at a rotor speed of 1.1 million rpm.

An All-Metal Compliant Seal Versus a Labyrinth Seal: A Comparison of Gas Leakage at High Temperatures

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Luis San Andrés ◽  
Alain Anderson
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
High Surface ◽  
Secondary Flows ◽  
Effect Of Temperature ◽  
Maximum Speed ◽  
The Novel ◽  
Steam Turbines ◽  
Flow Factor ◽  
Metal Seal

Parasitic secondary flows (seals' leakage) in centrifugal compressors and gas and steam turbines represent a substantial loss in efficiency and power delivery with an increase in specific fuel consumption. Labyrinth seals (LS) are the most common and inexpensive means of reducing secondary leakage, albeit wearing out with operation and thereby penalizing performance and even affecting rotordynamic stability. The novel hydrostatic advanced low leakage (HALO) seal is an all-metal seal with flexibly supported shoes that enable clearance self-control to effectively reduce leakage, in particular for operation with high pressure ratios and at high surface rotor speeds. This paper presents leakage tests with hot air (max. 300 °C) conducted in a test rig holding a LS and a HALO seal, both of similar diameter, axial length, and clearance. The novel seal leaks much less than the LS as the supply/discharge pressure ratio (Ps/Pa) increases. The leakage reduction is ∼50% for (Ps/Pa) < 2 and continuously dropping to 70% for (Ps/Pa) > 3.0. Thus, the savings in leakage are maximized for operation with a high pressure differential. Leakage measurements with a rotor spinning to a maximum speed of 2700 rpm (surface speed ∼24 m/s) produce a slight decrease in leakage for both seals. Characterization of seal leakage in terms of a flow factor removes the effect of temperature and supply pressure; the LS showing a constant flow factor for (Ps/Pa) > 2. Application of the novel seal technology will aid to increase system efficiency by reducing leakage and will extend maintenance intervals since it eliminates wear of components.

scholarly journals Impact of modified industrial wet pressing on the quantity and quality of Nile perch oil extracted from the viscera.

2019 ◽  
Author(s):  
DENNIS OTIENO ◽  
Nyaboke Hilda ◽  
Cyprian Odoli ◽  
Nyamweya Chrispine ◽  
Christopher Aura
Keyword(s):  
Fish Oil ◽  
Oil Quality ◽  
Maximum Yield ◽  
Extraction Process ◽  
Effect Of Temperature ◽  
Nile Perch ◽  
Omega 3 ◽  
Pressing Method ◽  
Wet Pressing

Global fish oil production is between 1 to 1.25 million tones and primarily exploiting fatty fish such as menhaden, herring, pilchards, anchovy, and sardine among others. The main producing countries include Japan, USA, Chile and Peru. Yet, fish oil from developing countries end up as bio waste since only the flesh is utilized. This paper discusses a simple approach for utilizing the fish bio waste to produce oil andhow the oil quality and quantityis impacted by the extraction process. The visceral organs were collected from fish filleting factory and markets in Kisumu town and oil extracted by modified wet pressing method adopted from Blight and Dyer (1959). The effect of temperature and serial washing on the oil quality and quantity was assessed from extraction temperatures at800C, 900C, 950C and 970C, while employing three serial washing using distilled water and pineapple juice. The quality of the oil produced was then determined based on the proportion of omega -3, vitamin A and E, peroxide value, iodine value and free fatty acids. Statistical analysis was conducted using R-data analysis software at P&lt;0.05 and ANOVA to determine significance. Results indicate that maximum extraction efficiency was achieved at 800C for 30 minutes where 157.66g of oil was extracted, when compared to 156.56g at 90ºC,156.49g at 95ºC,155.84g at 97ºC from a tissues of 171.25gin each case. It was concluded that the temperature manipulation procedures as per this study was reliable to produce maximum yield and can be adopted by oil producing plants. The study targets to utilize fish-biowaste which is dumped in aquatic systems that depletes dissolved oxygen levels in such ecosystems.

The effect of temperature, water input and length of growing season on sugar beet yield in five locations in Greece

2013 ◽  
Vol 152 (2) ◽  
pp. 177-187 ◽  
Author(s):  
J. T. TSIALTAS ◽  
N. MASLARIS
Keyword(s):  
Sugar Beet ◽  
Field Experiments ◽  
Maximum Yield ◽  
Growing Season ◽  
Effect Of Temperature ◽  
Maximum Temperature ◽  
Daily Minimum Temperature ◽  
Daily Maximum Temperature ◽  
Daily Maximum ◽  
Root Weight

SUMMARYFrom 1999 to 2006, 36 field experiments were conducted in five sugar beet growing areas in Greece (Larissa, Plati, Serres, Xanthi and Orestiada) to monitor yield. Locations differed significantly regarding thermal variables during the growing season with Xanthi having the most favourable thermal conditions (Tmax, average daily maximum temperature;Tmean, average daily mean temperature; GDD, growing degree days) for sugar beet growth. From early June to the end of the harvesting campaign, successive harvests were conducted. Over the years, fresh root weight and sugar yield at the last harvest of the season (FRWLH, SYLH) did not differ significantly among locations. Also, there were no significant differences among locations regarding GDD for maximum FRW and SY (GDDMFRW, GDDMSY), with the means over location estimated at 2639·9 and 2792·5 °C, respectively. Days after seeding (DAS) necessary for maximum yield (DASMFRW, DASMSY, respectively) differed among locations, with the longest period (DASMFRW206·4 days, DASMSY: 204·5 days) occurring in the northernmost location (Orestiada). Means for DASMFRWand DASMSYat the five locations were estimated at 190·4 and 188·9·days, respectively. Excluding Xanthi and combining the remaining locations, FRWLHand SYLHwere negatively correlated with the average temperatures (Tmean,TmaxandTmin, daily minimum temperature) over the growing season. The opposite was evident for Xanthi where sugar beet was grown under sub-optimal temperatures. The optimum meanTmaxof the five locations was estimated at 25·5 and 25·1 °C for FRWLHand SYLH, respectively. Elongation of the growing season, by means of early sowing, would increase yield by decreasing average temperatures (Tmean,Tmax) over the growing season in locations with the highest recorded temperatures (Larissa, Plati, Serres and Orestiada). In Xanthi, the projected temperature increase, as a result of climate change, is expected to have a positive effect on yields.

An All-Metal Compliant Seal Versus a Labyrinth Seal: A Comparison of Gas Leakage at High Temperatures

2014 ◽  
Author(s):  
Luis San Andrés ◽  
Alain Anderson
Keyword(s):  
High Pressure ◽  
Pressure Ratio ◽  
High Surface ◽  
Labyrinth Seal ◽  
Secondary Flows ◽  
Effect Of Temperature ◽  
Maximum Speed ◽  
The Novel ◽  
Flow Factor ◽  
Metal Seal

Parasitic secondary flows (seals’ leakage) in centrifugal compressors and gas and steam turbines represent a substantial loss in efficiency and power delivery with an increase in specific fuel consumption. Labyrinth seals are the most common and inexpensive means of reducing secondary leakage, albeit wearing out with operation and thereby penalizing performance and even affecting rotordynamic stability. The novel Hydrostatic Advanced Low Leakage (HALO) seal is an all-metal seal with flexibly supported shoes that enable clearance self-control to effectively reduce leakage, in particular for operation with high pressure ratios and at high surface rotor speeds. This paper presents leakage tests with hot air (max. 300°C) conducted in a test rig holding a labyrinth seal and a HALO seal, both of similar diameter, axial length and clearance. The novel seal leaks much less than the labyrinth seal as the supply/discharge pressure ratio (Ps/Pa) increases. The leakage reduction is ∼50% for (Ps/Pa) < 2 and continuously dropping to 70% for (Ps/Pa) > 3.0. Thus, the savings in leakage are maximized for operation with a high pressure differential. Leakage measurements with a rotor spinning to a maximum speed of 2,700 rpm (surface speed ∼ 24 m/s) produce a slight decrease in leakage for both seals. Characterization of seal leakage in terms of a flow factor removes the effect of temperature and supply pressure; the labyrinth seal showing a constant flow factor for (Ps/Pa) > 2. Application of the novel seal technology will aid to increase system efficiency by reducing leakage and will extend maintenance intervals since it eliminates wear of components.

Pyrolysis of Empty Fruit Bunch (EFB) in a Vertical Fixed Bed Reactor

2014 ◽  
Vol 695 ◽  
pp. 228-231 ◽  
Author(s):  
K. Azduwin ◽  
Mohd Jamir Mohd Ridzuan ◽  
A.R. Mohamed ◽  
S.M. Hafis
Keyword(s):  
Particle Size ◽  
Fossil Fuels ◽  
Pyrolysis Temperature ◽  
Hold Time ◽  
Maximum Yield ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Effect Of Temperature ◽  
Empty Fruit Bunch ◽  
Bio Oil

Uncontrolled uses of fossil fuels lead to serious energy problems and since Malaysia is one of the largest producers of palm oil in the world, it has caused a lot of waste such as empty fruit bunches (EFB) which can actually be converted into renewable energy via pyrolysis. In this work, firstly the characterizations of the EFB were analyzed such as elemental, proximate and component analysis. The pyrolysis experiment of empty fruit bunch using vertical fixed-bed reactor was conducted at different pyrolysis temperature range from 300 - 600 °C and the particle size of EFB was also varied from 125-250 μm with constant nitrogen flow rate of 100 cm3/min, heating rate of 30 °C/min, and 30 minutes hold time. For the effect of temperature, the optimum pyrolysis temperature was 500 °C to produce maximum yield of bio-oil which is 39.2 wt. % while 46.13 wt. % is the highest bio-oil yield produced at size of 500-710 μm for the effect of particle size. The analysis on bio-oil was conducted by using Fourier Transform Infrared (FTIR) with the results shows for the presents of phenol/alcohol group, ketones and C-O bond. The bio-oil obtained is in the acidic condition with pH 3.5.

scholarly journals EKSTRAKSI MULTI TAHAP KURKUMIN DARI TEMULAWAK (Curcuma xanthorriza Roxb.) MENGGUNAKAN PELARUT ETANOL

2015 ◽  
Vol 4 (2) ◽  
pp. 39-45 ◽  
Author(s):  
Dwimas Anggoro ◽  
Rajian Sobri Rezki ◽  
Siswarni MZ
Keyword(s):  
Extraction Method ◽  
Ethanol Concentration ◽  
Maximum Yield ◽  
Yellow Crystal ◽  
Extraction Time ◽  
Solvent Concentration ◽  
Multi Stage ◽  
Three Stages ◽  
Two Stages ◽  
Efficiency Rate

Curcumin is a pigment in turmeric (Curcuma xanthorriza Roxb.), which has an orange-yellow crystal appearance, and commonly being used as a colouring agent. Extraction method which is used in extracting curcumin from turmeric is one stage extraction. This research will study a multi stage extraction of curcumin from turmeric. The purposes of this research is to find the best condition in extracting curcumin using multi stages extraction method to increase the efficiency rate in curcumin extraction. This research used ethanol as a solvent, and effect from variables such as extraction time, solvent concentration, and number of extraction stages are observed. Extraction times are 60 minutes, 120 minutes, and 180 minutes. Variations of ethanol concentration are 50%, 70%, and 96%. Stage numbers of extraction are two stages extraction and three stages extraction. Extracts of curcumin are examined with qualitative analysis and quantitative analysis. The best condition of multi stages curcumin extraction is determined based on yield and content of curcumin. The maximum yield obtained in this study was 16,35 % with conditions 180 minutes extraction time, 96% ethanol concentration, and three stages extraction. The highest content of curcumin obtained is 2,617% with conditions 180 minutes extraction time, 96% ethanol concentration, and three stages extraction. Content means a fraction of yield. These results show that increase in the extraction time, the solvent concentration and the stage numbers of extraction will increase the yield and content of curcumin.

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