Characterization of metal adsorption kinetic properties in batch and fixed-bed reactors.

PubMed

Chen, J Paul; Wang, Lin

2004-01-01

Copper adsorption kinetic properties in batch and fixed-bed reactors were studied in this paper. The isothermal adsorption experiments showed that the copper adsorption capacity of a granular activated carbon (Filtrasorb 200) increased when ionic strength was higher. The presence of EDTA diminished the adsorption. An intraparticle diffusion model and a fixed-bed model were successfully used to describe the batch kinetic and fixed-bed operation behaviors. The kinetics became faster when the solution pH was not controlled, implying that the surface precipitation caused some metal uptake. The external mass transfer coefficient, the diffusivity and the dispersion coefficient were obtained from the modeling. It was found that both external mass transfer and dispersion coefficients increased when the flow rate was higher. Finally effects of kinetic parameters on simulation of fixed-bed operation were conducted.

Method of immobilizing carbon dioxide from gas streams

DOEpatents

Holladay, David W.; Haag, Gary L.

1979-01-01

This invention is a method for rapidly and continuously immobilizing carbon dioxide contained in various industrial off-gas streams, the carbon dioxide being immobilized as dry, stable, and substantially water-insoluble particulates. Briefly, the method comprises passing the gas stream through a fixed or fluidized bed of hydrated barium hydroxide to remove and immobilize the carbon dioxide by converting the bed to barium carbonate. The method has several important advantages: it can be conducted effectively at ambient temperature; it provides a very rapid reaction rate over a wide range of carbon dioxide concentrations; it provides high decontamination factors; and it has a high capacity for carbon dioxide. The invention is especially well suited for the removal of radioactive carbon dioxide from off-gases generated by nuclear-fuel reprocessing facilities and nuclear power plants.

Extraction of citral oil from lemongrass (Cymbopogon Citratus) by steam-water distillation technique

NASA Astrophysics Data System (ADS)

Alam, P. N.; Husin, H.; Asnawi, T. M.; Adisalamun

2018-04-01

In Indonesia, production of citral oil from lemon grass (Cymbopogon Cytratus) is done by a traditional technique whereby a low yield results. To improve the yield, an appropriate extraction technology is required. In this research, a steam-water distillation technique was applied to extract the essential oil from the lemongrass. The effects of sample particle size and bed volume on yield and quality of citral oil produced were investigated. The drying and refining time of 2 hours were used as fixed variables. This research results that minimum citral oil yield of 0.53% was obtained on sample particle size of 3 cm and bed volume of 80%, whereas the maximum yield of 1.95% on sample particle size of 15 cm and bed volume of 40%. The lowest specific gravity of 0.80 and the highest specific gravity of 0.905 were obtained on sample particle size of 8 cm with bed volume of 80% and particle size of 12 cm with bed volume of 70%, respectively. The lowest refractive index of 1.480 and the highest refractive index of 1.495 were obtained on sample particle size of 8 cm with bed volume of 70% and sample particle size of 15 cm with bed volume of 40%, respectively. The solubility of the produced citral oil in alcohol was 70% in ratio of 1:1, and the citral oil concentration obtained was around 79%.

Fixed-bed adsorption of reactive azo dye onto granular activated carbon prepared from waste.

PubMed

Ahmad, A A; Hameed, B H

2010-03-15

In this work, the adsorption potential of bamboo waste based granular activated carbon (BGAC) to remove C.I. Reactive Black (RB5) from aqueous solution was investigated using fixed-bed adsorption column. The effects of inlet RB5 concentration (50-200mg/L), feed flow rate (10-30 mL/min) and activated carbon bed height (40-80 mm) on the breakthrough characteristics of the adsorption system were determined. The highest bed capacity of 39.02 mg/g was obtained using 100mg/L inlet dye concentration, 80 mm bed height and 10 mL/min flow rate. The adsorption data were fitted to three well-established fixed-bed adsorption models namely, Adam's-Bohart, Thomas and Yoon-Nelson models. The results fitted well to the Thomas and Yoon-Nelson models with coefficients of correlation R(2)>or=0.93 at different conditions. The BGAC was shown to be suitable adsorbent for adsorption of RB5 using fixed-bed adsorption column. (c) 2009 Elsevier B.V. All rights reserved.

[Comparison of PAHs distribution in stabilized sludge by sludge drying bed and reed bed].

PubMed

Cui, Yu-Bo; Sun, Hong-Jie; Ran, Chun-Qiu; Li, Jin-Feng; Xie, Yao

2013-03-01

The difference in the removal efficiencies of polycyclic aromatic hydrocarbons (PAHs) in planted and unplanted sludge drying bed was investigated. Pilot-scale sludge drying bed and reed bed had the same size of 3.0 m x 1.0 m x 1.3 m (L x W x H), and the bed height consisted of a 65 cm media layer and a 65 cm super height. Both beds had a ventilation pipe which was mounted on the drainage pipes. The experiment lasted for three years, and the first two years was the sludge loading period, and the third year was the natural stabilization period. In the first two years, a total thickness of 8.4 m of sludge was loaded and the average sludge loading rate was 41.3 kg x (m2 x a)(-1). After the three-year stabilization, the contents of the sixteen PAHs decreased with time in both the sludge drying bed and the reed bed. The total PAHs contents in the surface, middle and bottom sludge layers in the sludge drying bed were 4.161, 3.543 and 3.118 mg x kg(-1) (DW), corresponding to 26.91%, 37.77% and 45.23% of removal; and the values in the reed bed were 2.722, 1.648 and 1.218 mg x kg(-1) (DW), corresponding to 52.18%, 71.05% and 78.60% of removal. The average PAHs removal in the reed bed was 29.86% higher than that in the sludge drying bed. In the stabilized sludge, the removal of low-molecular-weight PAHs predominated. The results suggested that reed played a positive role in the removal of PAHs.

Recent advances in fluidized bed drying

NASA Astrophysics Data System (ADS)

Haron, N. S.; Zakaria, J. H.; Mohideen Batcha, M. F.

2017-09-01

Fluidized bed drying are very well known to yield high heat and mass transfer and hence adopted to many industrial drying processes particularly agricultural products. In this paper, recent advances in fluidized bed drying were reviewed and focus is given to the drying related to the usage of Computational Fluid Dynamics (CFD). It can be seen that usage of modern computational tools such as CFD helps to optimize the fluidized bed dryer design and operation for lower energy consumption and thus better thermal efficiency. Among agricultural products that were reviewed in this paper were oil palm frond, wheat grains, olive pomace, coconut, pepper corn and millet.

Fluidized bed drying characteristics and modeling of ginger ( zingiber officinale) slices

NASA Astrophysics Data System (ADS)

Parlak, Nezaket

2015-08-01

In this study fluidized bed drying characteristics of ginger have been investigated. The effects of the fluidizing air temperature, velocity, humidity and bed height on the drying performance of ginger slices have been found. The experimental moisture loss data of ginger slices has been fitted to the eight thin layer drying models. Two-term model drying model has shown a better fit to the experimental data with R2 of 0.998 as compared to others.

Effects of bedding quality on lying behavior of dairy cows.

PubMed

Fregonesi, J A; Veira, D M; von Keyserlingk, M A G; Weary, D M

2007-12-01

Cows prefer to spend more time lying down in free stalls with more bedding, but no research to date has addressed the effects of bedding quality. Bedding in stalls often becomes wet either from exposure to the elements or from feces and urine. The aim of this study was to test the effect of wet bedding on stall preference and use. Four groups of 6 nonlactating Holstein cows were housed in free stalls bedded daily with approximately 0.1 m of fresh sawdust. Following a 5-d adaptation period, each group of cows was tested sequentially with access to stalls with either dry or wet sawdust bedding (86.4 +/- 2.1 vs. 26.5 +/- 2.1% dry matter), each for 2 d. These no-choice phases were followed by a 2-d free-choice phase during which cows had simultaneous access to stalls containing either wet or dry bedding. Stall usage was assessed by using 24-h video recordings scanned at 10-min intervals, and responses were analyzed by using a mixed model, with group (n = 4) as the observational unit. The minimum and maximum environmental temperatures during the experiment were 3.4 +/- 2.2 and 6.8 +/- 2.5 degrees C, respectively. When cows had access only to stalls with wet bedding, they spent 8.8 +/- 0.8 h/d lying down, which increased to 13.8 +/- 0.8 h/d when stalls with dry bedding were provided. Cows spent more time standing with their front 2 hooves in the stall when provided with wet vs. dry bedding (92 +/- 10 vs. 32 +/- 10 min/d). During the free-choice phase, all cows spent more time lying down in the dry stalls, spending 12.5 +/- 0.3 h/d in the dry stalls vs. 0.9 +/- 0.3 h/ d in stalls with wet bedding. In conclusion, dairy cows show a clear preference for a dry lying surface, and they spend much more time standing outside the stall when only wet bedding is available.

Adsorption of ciprofloxacin and norfloxacin from aqueous solution onto granular activated carbon in fixed bed column.

PubMed

Darweesh, Teeba M; Ahmed, Muthanna J

2017-04-01

Carbonization of Phoenix dactylifera L stones followed by microwave K 2 CO 3 activation was adopted for preparation of granular activated carbon (KAC). High yield and favorable pore characteristics in terms of surface area and pore volume were reported for KAC as follows: 44%, 852m 2 /g, and 0.671cm 3 /g, respectively. The application of KAC as adsorbent for attraction of ciprofloxacin (CIP) and norfloxacin (NOR) was investigated using fixed bed systems. The effect of flow rate (0.5-1.5ml/min), bed height (15-25cm), and initial drug concentration (75-225mg/l) on the behavior of breakthrough curves was explained. The fixed bed analysis showed the better correlation of breakthrough data by both Thomas and Yoon-Nelson models. Inlet drug concentration was of greatest effect on breakthrough data compared to other fixed bed variables. Experimental and calculated breakthrough data were obtained for CIP and NOR adsorption on KAC, thus being important for design of fixed bed column. Copyright © 2016 Elsevier Inc. All rights reserved.

Dynamic transition between fixed- and mobile-bed: mathematical and numerical aspects

NASA Astrophysics Data System (ADS)

Zugliani, Daniel; Pasqualini, Matteo; Rosatti, Giorgio

2017-04-01

Free-surface flows with high sediment transport (as debris flow or hyper-concentrated flow) are composed by a mixture of fluid and solid phase, usually water and sediment. When these flows propagate over loose beds, particles constituting the mixture of water and sediments strongly interact with the ones forming the bed, leading to erosion or deposition. However, there are lots of other situations when the mixture flows over rigid bedrocks or over artificially paved transects, so there is no mass exchange between bed and mixture. The two situations are usually referred to as, respectively, mobile- and fixed-bed conditions. From a mathematical point of view, the systems of Partial Differential Equations (PDEs) that describe these flows derive from mass and momentum balance of both phases, but, the two resulting PDEs systems are different. The main difference concerns the concentration: in the mobile-bed condition, the concentration is linked to the local flow conditions by means of a suitable rheological relation, while in the fixed-bed case, the concentration is an unknown of the problem. It is quite common that a free surface flow with high sediment transport, in its path, encounters both conditions. In the recent work of Rosatti & Zugliani 2015, the mathematical and numerical description of the transition between fixed- and mobile-bed was successfully resolved, for the case of low sediment transport phenomena, by the introduction of a suitable erodibility variable and satisfactory results were obtained. The main disadvantage of the approach is related to the erodibility variable, that changes in space, based on bed characteristics, but remains constant in time. However, the nature of the bed can change dynamically as result of deposition over fixed bed or high erosion over mobile bed. With this work, we extend the applicability of the mentioned approach to the more complex PDEs describing the hyper-concentrated flow. Moreover, we introduce a strategy that allows a dynamic time variation of the erodibility variable. The issue of the dynamic transition between fixed- and mobile-bed condition is tackled, from a numerical point of view, using a particular predictor corrector technique that compare the transported concentration related with the fixed bed and the equilibrium concentration, deriving from a closure relation, associated to the mobile bed condition. Through a comparison between exact solution, built using the generalized Rankine - Hugoniot condition, and the numeric results, we highlight capabilities and limits of this enhanced technique. Bibliography: G. Rosatti and D. Zugliani, 2015. "Modelling the transition between fixed and mobile bed conditions in two-phase free-surface flows: The Composite Riemann Problem and its numerical solution". Journal of Computational Physics, 285:226-250

[Thermal energy utilization analysis and energy conservation measures of fluidized bed dryer].

PubMed

Xing, Liming; Zhao, Zhengsheng

2012-07-01

To propose measures for enhancing thermal energy utilization by analyzing drying process and operation principle of fluidized bed dryers,in order to guide optimization and upgrade of fluidized bed drying equipment. Through a systematic analysis on drying process and operation principle of fluidized beds,the energy conservation law was adopted to calculate thermal energy of dryers. The thermal energy of fluidized bed dryers is mainly used to make up for thermal consumption of water evaporation (Qw), hot air from outlet equipment (Qe), thermal consumption for heating and drying wet materials (Qm) and heat dissipation to surroundings through hot air pipelines and cyclone separators. Effective measures and major approaches to enhance thermal energy utilization of fluidized bed dryers were to reduce exhaust gas out by the loss of heat Qe, recycle dryer export air quantity of heat, preserve heat for dry towers, hot air pipes and cyclone separators, dehumidify clean air in inlets and reasonably control drying time and air temperature. Such technical parameters such air supply rate, air inlet temperature and humidity, material temperature and outlet temperature and humidity are set and controlled to effectively save energy during the drying process and reduce the production cost.

40 CFR 265.1033 - Standards: Closed-vent systems and control devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... carbon adsorption system such as a fixed-bed carbon adsorber that regenerates the carbon bed directly in... using a carbon adsorption system such as a fixed-bed carbon adsorber that regenerates the carbon bed... established as a requirement of § 265.1035(b)(4)(iii)(F). (h) An owner or operator using a carbon adsorption...

Performance evaluation of two black nickel and two black chrome solar collectors

NASA Technical Reports Server (NTRS)

Losey, R.

1977-01-01

The test program was based on the evaluation of four unique solar collectors described below: (1) black nickel collector surface with a desiccant drying bed, (2) black nickel collector surface without a desiccant drying bed, (3) black chrome collector surface with a dessicant drying bed, and (4) black chrome collector surface without a desiccant drying bed. The test program included three distinct phases: Initial performance evaluation, natural environmental aging, and post-aging performance evaluation. Results of Phase III testing conclusively indicated a higher normalized efficiency for Black Chrome surfaces when compared to Black Nickel.

Heat and mass transfer within partially wetted packed fractured granular beds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalil, E.B.; Karim, G.A.

1996-10-01

Fractured granular beds heated by hot gaseous streams have been the subject of numerous investigations in recent years due to their importance in many applications such as in in-situ and enhanced oil recovery. In a previous paper (Khalil and Karim, 1995) the results of an investigation of some aspects of the transport processes that occur within dry granular beds were reported. The present contribution examines similar beds when partially wetted. The granular beds were cylindrical in shape containing an axial central small diameter circular channel representing a fracture which can have different permeability from that of the main bed. Itmore » is shown that the mass flow rate of the hot gases, the relative permeability of the bed and the central channel as well as the initial liquid content of the bed control the drying rate. The results of an analytical model formulated to simulate the drying process in unobstructed channel beds showed good agreement with experimental results at low temperatures, however deviations occurred as the drying proceeds at higher temperatures.« less

Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed.

PubMed

Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

2015-05-01

In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on the combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k-ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW. Copyright © 2015 Elsevier Ltd. All rights reserved.

Study of the optimisation of puffing characteristics of potato cubes by spouted bed drying enhanced with microwave.

PubMed

Yan, Wei-qiang; Zhang, Min; Huang, Lue-lue; Tang, Juming; Mujumdar, Arun S; Sun, Jin-cai

2010-06-01

In commercial deep-fat frying of potato chips, the oil content of the final products ranges from 35 to 45 g 100 g(-1) (wet basis). High-temperature frying may cause the formation of acrylamide, making the products unhealthy to the consumer. The aim of this research was to explore a new method, spouted bed microwave drying, to produce healthier puffed snack potato cubes as possible alternatives to oil-fried potato chips. The influence of drying conditions of the spouted bed microwave drying on puffing characteristics of potato cubes were studied and compared with the direct microwave and hot air drying method. Tandem combination drying of microwave-enhanced spouted bed drying (MWSB) could achieve a good expansion ratio, breaking force and rehydration ratio. The puffing characteristics of potato cubes were significantly affected (P < 0.05) by moisture content before starting microwave power in spouted bed microwave drying, by microwave (MW) power, and by the original size of potato cubes. The optimum processing parameters were the moisture content at the start of microwave power (60%), the size of potato cubes (10-12 mm), and microwave power (2-2.5 W g(-1)) Copyright (c) 2010 Society of Chemical Industry.

Effects of sawdust bedding dry matter on lying behavior of dairy cows: a dose-dependent response.

PubMed

Reich, L J; Weary, D M; Veira, D M; von Keyserlingk, M A G

2010-04-01

The objective was to determine the effect of sawdust bedding dry matter on the lying behavior of Holstein cows. Dry matter (DM) was varied systematically over 5 treatment levels to test how cows respond to damp bedding. This experiment was repeated during summer and winter to test if the effects of damp bedding varied with season. The 5 bedding treatments averaged (+/-SD) 89.8+/-3.7, 74.2+/-6.4, 62.2+/-6.3, 43.9+/-4.0, and 34.7+/-3.8% DM. Over the course of the trial, minimum and maximum temperatures in the barn were 2.6+/-2.0 and 6.8+/-2.2 degrees C in the winter and 13.3+/-2.5 and 22.6+/-4.1 degrees C in the summer. In both seasons, 5 groups of 3 nonlactating cows were housed in free stalls bedded with sawdust. Following a 5-d acclimation period on dry bedding, groups were exposed to the 5 bedding treatments in a 5 x 5 Latin square. Each treatment lasted 4 d, followed by 1 d when the cows were provided with dry bedding. Stall usage was assessed by 24-h video scanned at 5-min intervals. Responses were analyzed within group (n=5) as the observational unit. Bedding DM affected lying time, averaging 10.4+/-0.4 h/d on the wettest treatment and increasing to 11.5+/-0.4 h/d on the driest bedding. Lying time varied with season, averaging 12.1+/-0.4 h/d across treatments during the winter and 9.9+/-0.6 h/d during the summer, but season and bedding DM did not interact. These results indicate that access to dry bedding is important for dairy cows. Copyright (c) 2010 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Integrated drying and incineration of wet sewage sludge in combined bubbling and circulating fluidized bed units.

PubMed

Li, Shiyuan; Li, Yunyu; Lu, Qinggang; Zhu, Jianguo; Yao, Yao; Bao, Shaolin

2014-12-01

An original integrated drying and incineration technique is proposed to dispose of sewage sludge with moisture content of about 80% in a circulating fluidized bed. This system combines a bubbling fluidized bed dryer with a circulating fluidized bed incinerator. After drying, sewage sludge with moisture less than 20% is transported directly and continuously from the fluidized bed dryer into a circulating fluidized bed incinerator. Pilot plant results showed that integrated drying and incineration is feasible in a unique single system. A 100 t/d Sewage Sludge Incineration Demonstration Project was constructed at the Qige sewage treatment plant in Hangzhou City in China. The operational performance showed that the main operation results conformed to the design values, from which it can be concluded that the scale-up of this technique is deemed both feasible and successful. Copyright © 2014 Elsevier Ltd. All rights reserved.

Preliminary investigation on the production of fuels and bio-char from Chlamydomonas reinhardtii biomass residue after bio-hydrogen production.

PubMed

Torri, Cristian; Samorì, Chiara; Adamiano, Alessio; Fabbri, Daniele; Faraloni, Cecilia; Torzillo, Giuseppe

2011-09-01

The aim of this work was to investigate the potential conversion of Chlamydomonas reinhardtii biomass harvested after hydrogen production. The spent algal biomass was converted into nitrogen-rich bio-char, biodiesel and pyrolysis oil (bio-oil). The yield of lipids (algal oil), obtained by solvent extraction, was 15 ± 2% w/w(dry-biomass). This oil was converted into biodiesel with a 8.7 ± 1% w/w(dry-biomass) yield. The extraction residue was pyrolysed in a fixed bed reactor at 350 °C obtaining bio-char as the principal fraction (44 ± 1% w/w(dry-biomass)) and 28 ± 2% w/w(dry-biomass) of bio-oil. Pyrolysis fractions were characterized by elemental analysis, while the chemical composition of bio-oil was fully characterized by GC-MS, using various derivatization techniques. Energy outputs resulting from this approach were distributed in hydrogen (40%), biodiesel (12%) and pyrolysis fractions (48%), whereas bio-char was the largest fraction in terms of mass. Copyright © 2011 Elsevier Ltd. All rights reserved.

MHD oxidant intermediate temperature ceramic heater study

NASA Technical Reports Server (NTRS)

Carlson, A. W.; Chait, I. L.; Saari, D. P.; Marksberry, C. L.

1981-01-01

The use of three types of directly fired ceramic heaters for preheating oxygen enriched air to an intermediate temperature of 1144K was investigated. The three types of ceramic heaters are: (1) a fixed bed, periodic flow ceramic brick regenerative heater; (2) a ceramic pebble regenerative heater. The heater design, performance and operating characteristics under conditions in which the particulate matter is not solidified are evaluated. A comparison and overall evaluation of the three types of ceramic heaters and temperature range determination at which the particulate matter in the MHD exhaust gas is estimated to be a dry powder are presented.

Flow near a model spur dike with a fixed scoured bed

USDA-ARS?s Scientific Manuscript database

Three-dimensional flow velocities were measured using an acoustic Doppler velocimeter at a closely spaced grid over a fixed scoured bed with a submerged spur dike. Three-dimensional flow velocities were measured at 3484 positions around the trapezoidal shaped submerged model spur dike over a fixed ...

29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 29 Labor 5 2011-07-01 2011-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet a...

29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 29 Labor 5 2010-07-01 2010-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet a...

29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 29 Labor 5 2013-07-01 2013-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet a...

29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 29 Labor 5 2014-07-01 2014-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet a...

29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 29 Labor 5 2012-07-01 2012-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet a...

Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Rui, E-mail: Sunsr@hit.edu.cn; Ismail, Tamer M., E-mail: temoil@aucegypt.edu; Ren, Xiaohan

Highlights: • The effects of moisture content on the burning process of MSW are investigated. • A two-dimensional mathematical model was built to simulate the combustion process. • Temperature distributions, process rates, gas species were measured and simulated. • The The conversion ratio of C/CO and N/NO in MSW are inverse to moisture content. - Abstract: In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on themore » combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k–ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW.« less

Porous filtering media comparison through wet and dry sampling of fixed bed gasification products

NASA Astrophysics Data System (ADS)

Allesina, G.; Pedrazzi, S.; Montermini, L.; Giorgini, L.; Bortolani, G.; Tartarini, P.

2014-11-01

The syngas produced by fixed bed gasifiers contains high quantities of particulate and tars. This issue, together with its high temperature, avoids its direct exploitation without a proper cleaning and cooling process. In fact, when the syngas produced by gasification is used in an Internal Combustion engine (IC), the higher the content of tars and particulate, the higher the risk to damage the engine is. If these compounds are not properly removed, the engine may fail to run. A way to avoid engine fails is to intensify the maintenance schedule, but these stops will reduce the system profitability. From a clean syngas does not only follow higher performance of the generator, but also less pollutants in the atmosphere. When is not possible to work on the gasification reactions, the filter plays the most important role in the engine safeguard process. This work is aimed at developing and comparing different porous filters for biomass gasifiers power plants. A drum filter was developed and tested filling it with different filtering media available on the market. As a starting point, the filter was implemented in a Power Pallet 10 kW gasifier produced by the California-based company "ALL Power Labs". The original filter was replaced with different porous biomasses, such as woodchips and corn cobs. Finally, a synthetic zeolites medium was tested and compared with the biological media previously used. The Tar Sampling Protocol (TSP) and a modified "dry" method using the Silica Gel material were applied to evaluate the tars, particulate and water amount in the syngas after the filtration process. Advantages and disadvantages of every filtering media chosen were reported and discussed.

Fluidized-Bed Drying and Storage Stability of Cryptococcus flavescens OH 182.9, a Biocontrol Agent of Fusarium Head Blight

USDA-ARS?s Scientific Manuscript database

A method to produce dried granules of Cryptococcus flavescens (formerly Cryptococcus nodaensis) OH 182.9 was developed and the granules evaluated for storage stability. Small spherical granules were produced and dried using a fluidized bed dryer. A drying and survival curve was produced for the pr...

Fluidization and drying of biomass particles in a vibrating fluidized bed with pulsed gas flow

DOE PAGES

Jia, Dening; Cathary, Océane; Peng, Jianghong; ...

2015-10-01

Fluidization of biomass particles in the absence of inert bed materials has been tested in a pulsed fluidized bed with vibration, with the pulsation frequency ranging from 033 to 6.67 Hz. Intermittent fluidization at 033 Hz and apparently 'normal' fluidization at 6.67 Hz with regular bubble patterns were observed. Pulsation has proven to be effective in overcoming the bridging of irregular biomass particles induced by strong inter-particle forces. The vibration is only effective when the pulsation is inadequate, either at too low a frequency or too low in amplitude. We dried biomass in order to quantify the effectiveness of gasmore » pulsation for fluidized bed dryers and torrefiers in terms of gas-solid contact efficiency and heat and mass transfer rates. Furthermore, the effects of gas flow rate, bed temperature, pulsation frequency and vibration intensity on drying performance have been systematically investigated. While higher temperature and gas flow rate are favored in drying, there exists an optimal range of pulsation frequency between 0.75 Hz and 1.5 Hz where gas-solid contact is enhanced in both the constant rate drying and falling rate drying periods.« less

Impact of feedstock properties and operating conditions on sewage sludge gasification in a fixed bed gasifier.

PubMed

Werle, Sebastian

2014-10-01

This work presents results of experimental studies on the gasification process of granulated sewage sludge in a laboratory fixed bed gasifier. Nowadays, there is a large and pressing need for the development of thermal methods for sewage sludge disposal. Gasification is an example of thermal method that has several advantages over the traditional combustion. Gasification leads to a combustible gas, which can be used for the generation of useful forms of final energy. It can also be used in processes, such as the drying of sewage sludge directly in waste treatment plant. In the present work, the operating parameters were varied over a wide range. Parameters, such as air ratio λ = 0.12 to 0.27 and the temperature of air preheating t = 50 °C to 250 °C, were found to influence temperature distribution and syngas properties. The results indicate that the syngas heating value decreases with rising air ratio for all analysed cases: i.e. for both cold and preheated air. The increase in the concentration of the main combustible components was accompanied by a decrease in the concentration of carbon dioxide. Preheating of the gasification agent supports the endothermic gasification and increases hydrogen and carbon monoxide production. © The Author(s) 2014.

Batch and fixed-bed column study for p-nitrophenol, methylene blue, and U(VI) removal by polyvinyl alcohol-graphene oxide macroporous hydrogel bead.

PubMed

Chen, Dan; Zhou, Jun; Wang, Hongyu; Yang, Kai

2018-01-01

There is an increasing need to explore effective and clean approaches for hazardous contamination removal from wastewaters. In this work, a novel bead adsorbent, polyvinyl alcohol-graphene oxide (PVA-GO) macroporous hydrogel bead was prepared as filter media for p-nitrophenol (PNP), dye methylene blue (MB), and heavy metal U(VI) removal from aqueous solution. Batch and fixed-bed column experiments were carried out to evaluate the adsorption capacities of PNP, MB, and U(VI) on this bead. From batch experiments, the maximum adsorption capacities of PNP, MB, and U(VI) reached 347.87, 422.90, and 327.55 mg/g. From the fixed-bed column experiments, the adsorption capacities of PNP, MB, and U(VI) decreased with initial concentration increasing from 100 to 400 mg/L. The adsorption capacities of PNP, MB, and U(VI) decreased with increasing flow rate. Also, the maximum adsorption capacity of PNP decreased as pH increased from 3 to 9, while MB and U(VI) presented opposite tendencies. Furthermore, the bed depth service Time (BDST) model showed good linear relationships for the three ions' adsorption processes in this fixed-bed column, which indicated that the BDST model effectively evaluated and optimized the adsorption process of PVA-GO macroporous hydrogel bead in fixed-bed columns for hazardous contaminant removal from wastewaters.

Thin layer drying of cassava starch using continuous vibrated fluidized bed dryer

NASA Astrophysics Data System (ADS)

Suherman, Trisnaningtyas, Rona

2015-12-01

This paper present the experimental work and thin layer modelling of cassava starch drying in continuous vibrated fluidized bed dryer. The experimental data was used to validate nine thin layer models of drying curve. Cassava starch with 0.21 initial moisture content was dried in different air drying temperature (50°C, 55°C, 60°C, 65°C, 70°C), different weir height in bed (0 and 1 cm), and different solid feed flow (10 and 30 gr.minute-1). The result showed air dryer temperature has a significant effect on drying curve, while the weir height and solid flow rate are slightly. Based on value of R2, χ2, and RMSE, Page Model is the most accurate simulation for thin layer drying model of cassava starch.

Method of shielding a liquid-metal-cooled reactor

DOEpatents

Sayre, Robert K.

1978-01-01

The primary heat transport system of a nuclear reactor -- particularly for a liquid-metal-cooled fast-breeder reactor -- is shielded and protected from leakage by establishing and maintaining a bed of a powdered oxide closely and completely surrounding all components thereof by passing a gas upwardly therethrough at such a rate as to slightly expand the bed to the extent that the components of the system are able to expand without damage and yet the particles of the bed remain close enough so that the bed acts as a guard vessel for the system. Preferably the gas contains 1 to 10% oxygen and the gas is passed upwardly through the bed at such a rate that the lower portion of the bed is a fixed bed while the upper portion is a fluidized bed, the line of demarcation therebetween being high enough that the fixed bed portion of the bed serves as guard vessel for the system.

Effects of natural organic matter on PCB-activated carbon sorption kinetics: implications for sediment capping applications.

PubMed

Fairey, Julian L; Wahman, David G; Lowry, Gregory V

2010-01-01

In situ capping of polychlorinated biphenyl (PCB)-contaminated sediments with a layer of activated carbon has been proposed, but several questions remain regarding the long-term effectiveness of this remediation strategy. Here, we assess the degree to which kinetic limitations, size exclusion effects, and electrostatic repulsions impaired PCB sorption to activated carbon. Sorption of 11 PCB congeners with activated carbon was studied in fixed bed reactors with organic-free water (OFW) and Suwannee River natural organic matter (SR-NOM), made by reconstituting freeze-dried SR-NOM at a concentration of 10 mg L(-1) as carbon. In the OFW test, no PCBs were detected in the column effluent over the 390-d study, indicating that PCB-activated carbon equilibrium sorption capacities may be achieved before breakthrough even at the relatively high hydraulic loading rate (HLR) of 3.1 m h(-1). However, in the SR-NOM fixed-bed test, partial PCB breakthrough occurred over the entire 320-d test (HLRs of 3.1-, 1.5-, and 0.8 m h(-1)). Simulations from a modified pore and surface diffusion model indicated that external (film diffusion) mass transfer was the dominant rate-limiting step but that internal (pore diffusion) mass transfer limitations were also present. The external mass transfer limitation was likely caused by formation of PCB-NOM complexes that reduced PCB sorption through a combination of (i) increased film diffusion resistance; (ii) size exclusion effects; and (iii) electrostatic repulsive forces between the PCBs and the NOM-coated activated carbon. However, the seepage velocities in the SR-NOM fixed bed test were about 1000 times higher than would be expected in a sediment cap. Therefore, additional studies are needed to assess whether the mass transfer limitations described here would be likely to manifest themselves at the lower seepage velocities observed in practice.

Manufacturing Solid Dosage Forms from Bulk Liquids Using the Fluid-bed Drying Technology.

PubMed

Qi, Jianping; Lu, Y I; Wu, Wei

2015-01-01

Solid dosage forms are better than liquid dosage forms in many ways, such as improved physical and chemical stability, ease of storage and transportation, improved handling properties, and patient compliance. Therefore, it is required to transform dosage forms of liquid origins into solid dosage forms. The functional approaches are to absorb the liquids by solid excipients or through drying. The conventional drying technologies for this purpose include drying by heating, vacuum-, freeze- and spray-drying, etc. Among these drying technologies, fluidbed drying emerges as a new technology that possesses unique advantages. Fluid-bed drying or coating is highly efficient in solvent removal, can be performed at relatively low temperatures, and is a one-step process to manufacture formulations in pellet forms. In this article, the status of the art of manufacturing solid dosage forms from bulk liquids by fluid-bed drying technology was reviewed emphasizing on its application in solid dispersion, inclusion complexes, self-microemulsifying systems, and various nanoscale drug delivery systems.

Assessment of Tree Leaves Flakes Mixed with Crude Glycerol as a Bioenergy Source

PubMed Central

Hilal-AlNaqbi, Ali; Al-Omari, Salah B.; Selim, Mohamed Y. E.

2016-01-01

The gasification and combustion of dry tree leaves and the cogasification of dry tree leaves soaking crude glycerol were studied experimentally. An updraft fixed bed gasification and combustion system was built. The operation was conducted at different air to fuel ratios. Results show more stable combustion and more effective heat transfer to furnace walls for the cases when tree leaves flakes are mixed with 20 percent (on mass basis) of crude glycerol, as compared with the case when only dry tree leaves are used as fuel. TGA analysis was also conducted for the two fuels used under both air and nitrogen environments. For the crude glycerol, four phases of pyrolysis and gasification were noticed under either of the two surrounding gaseous media (air or nitrogen). For the dry tree leaves, the pyrolysis under nitrogen shows only a simple smooth pyrolysis and gasification curve without showing the different distinct phases that were otherwise identified when the pyrolysis is conducted under air environment. Moreover, the air TGA results lead to more gasification due to the char oxidation at high temperatures. DTG results are also presented and discussed. PMID:27413749

Gaseous fuels production from dried sewage sludge via air gasification.

PubMed

Werle, Sebastian; Dudziak, Mariusz

2014-07-01

Gasification is a perspective alternative method of dried sewage sludge thermal treatment. For the purpose of experimental investigations, a laboratory fixed-bed gasifier installation was designed and built. Two sewage sludge (SS) feedstocks, taken from two typical Polish wastewater treatment systems, were analysed: SS1, from a mechanical-biological wastewater treatment system with anaerobic stabilization (fermentation) and high temperature drying; and (SS2) from a mechanical-biological-chemical wastewater treatment system with fermentation and low temperature drying. The gasification results show that greater oxygen content in sewage sludge has a strong influence on the properties of the produced gas. Increasing the air flow caused a decrease in the heating value of the produced gas. Higher hydrogen content in the sewage sludge (from SS1) affected the produced gas composition, which was characterized by high concentrations of combustible components. In the case of the SS1 gasification, ash, charcoal, and tar were produced as byproducts. In the case of SS2 gasification, only ash and tar were produced. SS1 and solid byproducts from its gasification (ash and charcoal) were characterized by lower toxicity in comparison to SS2. However, in all analysed cases, tar samples were toxic. © The Author(s) 2014.

Removal of emerging pharmaceutical contaminants by adsorption in a fixed-bed column: A review.

PubMed

Ahmed, M J; Hameed, B H

2018-03-01

Pharmaceutical pollutants substantially affect the environment; thus, their treatments have been the focus of many studies. In this article, the fixed-bed adsorption of pharmaceuticals on various adsorbents was reviewed. The experimental breakthrough curves of these pollutants under various flow rates, inlet concentrations, and bed heights were examined. Fixed-bed data in terms of saturation uptakes, breakthrough time, and the length of the mass transfer zone were included. The three most popular breakthrough models, namely, Adams-Bohart, Thomas, and Yoon-Nelson, were also reviewed for the correlation of breakthrough curve data along with the evaluation of model parameters. Compared with the Adams-Bohart model, the Thomas and Yoon-Nelson more effectively predicted the breakthrough data for the studied pollutants. Copyright © 2017 Elsevier Inc. All rights reserved.

Experimental study of cassava sun drying

DOE Office of Scientific and Technical Information (OSTI.GOV)

Njie, D.N.; Rumsey, T.R.

1997-03-01

Sun drying experiments were performed to compare drying of cassava chips in sheet-metal trays with drying on mesh wire trays. In the sheet-metal trays, there was air flow across the top of the bed chips, while the mesh wire trays permitted air to flow through the bed. Drying rate was faster and more uniform in the trays with through-flow air circulation. Higher temperatures were reached by chips in the sheet-metal trays than those in the mesh trays because of contact heating, but the drying rate was lower because of the reduced air flow.

Hydrogen-Rich Syngas Production from Gasification and Pyrolysis of Solar Dried Sewage Sludge: Experimental and Modeling Investigations

PubMed Central

Ghrib, Amina; Friaa, Athar; Ouerghi, Aymen; Naoui, Slim; Belayouni, Habib

2017-01-01

Solar dried sewage sludge (SS) conversion by pyrolysis and gasification processes has been performed, separately, using two laboratory-scale reactors, a fixed-bed pyrolyzer and a downdraft gasifier, to produce mainly hydrogen-rich syngas. Prior to SS conversion, solar drying has been conducted in order to reduce moisture content (up to 10%). SS characterization reveals that these biosolids could be appropriate materials for gaseous products production. The released gases from SS pyrolysis and gasification present relatively high heating values (up to 9.96 MJ/kg for pyrolysis and 8.02  9.96 MJ/kg for gasification) due to their high contents of H2 (up to 11 and 7 wt%, resp.) and CH4 (up to 17 and 5 wt%, resp.). The yields of combustible gases (H2 and CH4) show further increase with pyrolysis. Stoichiometric models of both pyrolysis and gasification reactions were determined based on the global biomass formula, CαHβOγNδSε, in order to assist in the products yields optimization. PMID:28856162

CTR Fuel recovery system using regeneration of a molecular sieve drying bed

DOEpatents

Folkers, Charles L.

1981-01-01

A primary molecular sieve drying bed is regenerated by circulating a hot inert gas through the heated primary bed to desorb water held on the bed. The inert gas plus water vapor is then cooled and passed through an auxiliary molecular sieve bed which adsorbs the water originally desorbed from the primary bed. The main advantage of the regeneration technique is that the partial pressure of water can be reduced to the 10.sup.-9 atm. range. This is significant in certain CTR applications where tritiated water (T.sub.2 O, HTO) must be collected and kept at very low partial pressure.

Energy monitoring and analysis during deformation of bedded-sandstone: use of acoustic emission.

PubMed

Wasantha, P L P; Ranjith, P G; Shao, S S

2014-01-01

This paper investigates the mechanical behaviour and energy releasing characteristics of bedded-sandstone with bedding layers in different orientations, under uniaxial compression. Cylindrical sandstone specimens (54 mm diameter and 108 mm height) with bedding layers inclined at angles of 10°, 20°, 35°, 55°, and 83° to the minor principal stress direction, were produced to perform a series of Uniaxial Compressive Strength (UCS) tests. One of the two identical sample sets was fully-saturated with water before testing and the other set was tested under dry conditions. An acoustic emission system was employed in all the testing to monitor the acoustic energy release during the whole deformation process of specimens. From the test results, the critical joint orientation was observed as 55° for both dry and saturated samples and the peak-strength losses due to water were 15.56%, 20.06%, 13.5%, 13.2%, and 13.52% for the bedding orientations 10°, 20°, 35°, 55°, and 83°, respectively. The failure mechanisms for the specimens with bedding layers in 10°, 20° orientations showed splitting type failure, while the specimens with bedding layers in 55°, 83° orientations were failed by sliding along a weaker bedding layer. The failure mechanism for the specimens with bedding layers in 35° orientation showed a mixed failure mode of both splitting and sliding types. Analysis of the acoustic energy, captured from the acoustic emission detection system, revealed that the acoustic energy release is considerably higher in dry specimens than that of the saturated specimens at any bedding orientation. In addition, higher energy release was observed for specimens with bedding layers oriented in shallow angles (which were undergoing splitting type failures), whereas specimens with steeply oriented bedding layers (which were undergoing sliding type failures) showed a comparatively less energy release under both dry and saturated conditions. Moreover, a considerable amount of energy dissipation before the ultimate failure was observed for specimens with bedding layers oriented in shallow angles under both dry and saturated conditions. These results confirm that when rock having bedding layers inclined in shallow angles the failures could be more violent and devastative than the failures of rock with steeply oriented bedding layers. Copyright © 2013 Elsevier B.V. All rights reserved.

Potential Regrowth and Recolonization of Salmonellae and Indicators in Biosolids and Biosolid-Amended Soil

PubMed Central

Zaleski, Kathleen J.; Josephson, Karen L.; Gerba, Charles P.; Pepper, Ian L.

2005-01-01

This study evaluated the potential for conversion of Class B to Class A biosolids with respect to salmonellae and fecal coliforms during solar drying in concrete lined drying beds. Anaerobically (8% solids) and aerobically (2% solids) digested Class B biosolids were pumped into field-scale drying beds, and microbial populations and environmental conditions were monitored. Numbers of fecal coliforms and salmonellae decreased as temperature and rate of desiccation increased. After 3 to 4 weeks, Class A requirements were achieved in both biosolids for the pathogens and the indicators. However, following rainfall events, significant increase in numbers was observed for both fecal coliforms and salmonellae. In laboratory studies, regrowth of fecal coliforms was observed in both biosolids and biosolid-amended soil, but the regrowth of salmonellae observed in the concrete-lined drying beds did not occur. These laboratory studies demonstrated that pathogens decreased in numbers when soil was amended with biosolids. Based on serotyping, the increased numbers of salmonellae seen in the concrete lined drying beds following rainfall events was most likely due to recolonization due to contamination from fecal matter introduced by animals and not from regrowth of salmonellae indigenous to biosolids. Overall, we conclude that the use of concrete-lined beds created a situation in which moisture added as rainfall accumulated in the beds, promoting the growth of fecal coliforms and salmonellae added from external sources. PMID:16000779

40 CFR 60.713 - Compliance provisions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operator of the affected coating operation shall perform a liquid-liquid VOC material balance over each and... emission control device (other than a fixed-bed carbon adsorption system with individual exhaust stacks for...) when a fixed-bed carbon adsorption system with individual exhaust stacks for each adsorber vessel is...

40 CFR 60.713 - Compliance provisions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... operator of the affected coating operation shall perform a liquid-liquid VOC material balance over each and... emission control device (other than a fixed-bed carbon adsorption system with individual exhaust stacks for...) when a fixed-bed carbon adsorption system with individual exhaust stacks for each adsorber vessel is...

40 CFR 60.713 - Compliance provisions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... operator of the affected coating operation shall perform a liquid-liquid VOC material balance over each and... emission control device (other than a fixed-bed carbon adsorption system with individual exhaust stacks for...) when a fixed-bed carbon adsorption system with individual exhaust stacks for each adsorber vessel is...

[Adsorption of the TiO2 @ yeast composite microspheres for adsorbing Fluorescent Whitening Agent-VBL in fixed bed].

PubMed

Wu, Fei; Zhang, Kai-Qiang; Bai, Bo; Wang, Hong-Lun; Suo, You-Rui

2015-02-01

In this work, the adsorption potential of TiO2@ yeast composite microspheres to remove Fluorescent Whitening Agent-VBL (FWA-VBL) from aqueous solution was investigated using fixed-bed adsorption column. The effects of pH(2.0-8.0), bed height (1-3 cm), inlet concentration (20-80 mg x L(-1)) and feed flow rate (5-11 mL x min(-1)) on the breakthrough characteristics of the adsorption system were determined. The results showed that the highest bed capacity of 223.80 mg x g(-1) was obtained under the condition of pH 2.0, 80 mg x L(-1) inlet dye concentration, 1.0 cm bed height and 5 mL x min(-1) flow rate. The adsorption data were fitted to three well-established fixed-bed adsorption models, namely, BDST model, Thomas model and Yoon-Nelson model. The results fitted well to the three models with coefficients of correlation R2 > 0.980 in different conditions. The TiO2 @ yeast composite microspheres have desired regeneration ability and could be reused for four times.

Effectiveness of bed bug monitors for detecting and trapping bed bugs in apartments.

PubMed

Wang, Changlu; Tsai, Wan-Tien; Cooper, Richard; White, Jeffrey

2011-02-01

Bed bugs, Cimex lectularius L., are now considered a serious urban pest in the United States. Because they are small and difficult to find, there has been strong interest in developing and using monitoring tools to detect bed bugs and evaluate the results of bed bug control efforts. Several bed bug monitoring devices were developed recently, but their effectiveness is unknown. We comparatively evaluated three active monitors that contain attractants: CDC3000, NightWatch, and a home-made dry ice trap. The Climbup Insect Interceptor, a passive monitor (without attractants), was used for estimating the bed bug numbers before and after placing active monitors. The results of the Interceptors also were compared with the results of the active monitors. In occupied apartments, the relative effectiveness of the active monitors was: dry ice trap > CDC3000 > NightWatch. In lightly infested apartments, the Interceptor (operated for 7 d) trapped similar number of bed bugs as the dry ice trap (operated for 1 d) and trapped more bed bugs than CDC3000 and NightWatch (operated for 1 d). The Interceptor was also more effective than visual inspections in detecting the presence of small numbers of bed bugs. CDC3000 and the dry ice trap operated for 1 d were equally as effective as the visual inspections for detecting very low level of infestations, whereas 1-d deployment of NightWatch detected significantly lower number of infestations compared with visual inspections. NightWatch was designed to be able to operate for several consecutive nights. When operated for four nights, NightWatch trapped similar number of bed bugs as the Interceptors operated for 10 d after deployment of NightWatch. We conclude these monitors are effective tools in detecting early bed bug infestations and evaluating the results of bed bug control programs.

Heterogeneous decomposition of silane in a fixed bed reactor

NASA Technical Reports Server (NTRS)

Iya, S. K.; Flagella, R. N.; Dipaolo, F. S.

1982-01-01

Heterogeneous decomposition of silane in a fluidized bed offers an attractive route for the low-cost production of silicon for photovoltaic application. To obtain design data for a fluid bed silane pyrolysis reactor, deposition experiments were conducted in a small-scale fixed bed apparatus. Data on the decomposition mode, plating rate, and deposition morphology were obtained in the temperature range 600-900 C. Conditions favorable for heterogeneous decomposition with good deposition morphology were identified. The kinetic rate data showed the reaction to be first order with an activation energy of 38.8 kcal/mol, which agrees well with work done by others. The results are promising for the development of an economically attractive fluid bed process.

FIXED-BED HYDROGENATION OF ORGANIC COMPOUNDS IN SUPERCRITICAL CARBON DIOXIDE. (R826034)

EPA Science Inventory

Abstract

The Pd/C hydrogenation of cyclohexene to cyclohexane was performed in a continuous fixed-bed reactor employing CO₂ to solubilize the reaction mixture in a single supercritical (sc) phase surrounding the solid catalyst. Employing an equimolar feed of...

40 CFR 60.745 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... determination of the efficiency of a fixed-bed carbon adsorption system with a common exhaust stack for all the... separate runs, each coinciding with one or more complete system rotations through the adsorption cycles of... efficiency of a fixed-bed carbon adsorption system with individual exhaust stacks for each adsorber vessel...

APPARATUS FOR SHORT TIME MEASUREMENTS IN A FIXED-BED, GAS/SOLID REACTOR

EPA Science Inventory

An apparatus for exposure of a solid to reactive process gas is described which makes possible short time (≥ 0.3 to 15 s) exposures in a fixed-bed reactor. Operating conditions for differential reaction with respect to the gas concentration and rapid quench for arresting hi...

40 CFR 60.745 - Test methods and procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... determination of the efficiency of a fixed-bed carbon adsorption system with a common exhaust stack for all the... separate runs, each coinciding with one or more complete system rotations through the adsorption cycles of... efficiency of a fixed-bed carbon adsorption system with individual exhaust stacks for each adsorber vessel...

Use of wood-based materials in beef bedded manure packs: 2. Effect on odorous volatile organic compounds, odor activity value, Escherichia coli, and nutrient concentrations

USDA-ARS?s Scientific Manuscript database

The objectives of this study were to determine the effects of three types of wood-based bedding materials (kiln-dried pine wood chips, dry cedar chips, and green cedar chips) and corn stover on concentration of odorous volatile organic compounds (VOC) and total Escherichia coli in bedded pack materi...

Pre-treatment processes of Azolla filiculoides to remove Pb(II), Cd(II), Ni(II) and Zn(II) from aqueous solution in the batch and fixed-bed reactors.

PubMed

Khosravi, Morteza; Rakhshaee, Roohan; Ganji, Masuod Taghi

2005-12-09

Intact and treated biomass can remove heavy metals from water and wastewater. This study examined the ability of the activated, semi-intact and inactivated Azolla filiculoides (a small water fern) to remove Pb(2+), Cd(2+), Ni(2+) and Zn(2+) from the aqueous solution. The maximum uptake capacities of these metal ions using the activated Azolla filiculoides by NaOH at pH 10.5 +/- 0.2 and then CaCl(2)/MgCl(2)/NaCl with total concentration of 2 M (2:1:1 mole ratio) in the separate batch reactors were obtained about 271, 111, 71 and 60 mg/g (dry Azolla), respectively. The obtained capacities of maximum adsorption for these kinds of the pre-treated Azolla in the fixed-bed reactors (N(o)) were also very close to the values obtained for the batch reactors (Q(max)). On the other hand, it was shown that HCl, CH(3)OH, C(2)H(5)OH, FeCl(2), SrCl(2), BaCl(2) and AlCl(3) in the pre-treatment processes decreased the ability of Azolla to remove the heavy metals in comparison to the semi-intact Azolla, considerably. The kinetic studies showed that the heavy metals uptake by the activated Azolla was done more rapid than those for the semi-intact Azolla.

Microcapsules loaded with the probiotic Lactobacillus paracasei BGP-1 produced by co-extrusion technology using alginate/shellac as wall material: Characterization and evaluation of drying processes.

PubMed

Silva, Marluci P; Tulini, Fabricio L; Ribas, Marcela M; Penning, Manfred; Fávaro-Trindade, Carmen S; Poncelet, Denis

2016-11-01

Microcapsules containing Lactobacillus paracasei BGP-1 were produced by co-extrusion technology using alginate and alginate-shellac blend as wall materials. Sunflower oil and coconut fat were used as vehicles to incorporate BGP-1 into the microcapsules. The microcapsules were evaluated with regard the particle size, morphology, water activity and survival of probiotics after 60days of storage at room temperature. Fluidized bed and lyophilization were used to dry the microcapsules and the effect of these processes on probiotic viability was also evaluated. Next, dried microcapsules were exposed to simulated gastrointestinal fluids to verify the survival of BGP-1. Microcapsules dried by fluidized bed had spherical shape and robust structures, whereas lyophilized microcapsules had porous and fragile structures. Dried microcapsules presented a medium size of 0.71-0.86mm and a w ranging from 0.14 to 0.36, depending on the drying process. When comparing the effects of drying processes on BGP-1 viability, the fluidized bed was less aggressive than lyophilization. The alginate-shellac blend combined with coconut fat as core effectively protected the encapsulated probiotic under simulated gastrointestinal conditions. Thus, the production of microcapsules by co-extrusion followed by drying using the fluidized bed is a promising strategy for protection of probiotic cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

Phytoremediation of selenium by two helophyte species in subsurface flow constructed wetland.

PubMed

Shardendu; Salhani, N; Boulyga, S F; Stengel, E

2003-03-01

The phytoremediation of selenium by two different wetland species was investigated. Selenium (20.4 microg/l) was supplied continuously to subsurface flow constructed wetlands, one vegetated with Typha latifolia L. and the other with Phragmites australis (Cav.) Trin. ex Steud. The beds of both species had same hydraulic loading rate (0.079 m(3)/m(2)/d) and water retention time (24 h). However, the mass loading rate was 1.27 mg Se/m(2)/d for Phragmites and 1.35 mg Se/m(2)/d for Typha. In the Typha bed Se migrated faster than in the Phragmites bed. After 25 d of Se supplementation in the Typha bed about 54% of the Se inlet concentration remained in the outlet water. In the Phragmites bed Se was removed completely from the water after passing through 3/4 of the bed length. After 65 d of Se supplementation the highest amount of Se (2.8 microg/g dry matter) was determined in the organic material of the Typha bed. Roots and rhizomes accumulated 2.2 and 1.8 microg/g dry matter respectively. Phragmites accumulated Se in the leaves and stems, but not in the rhizomes. The accumulation in the leaves (1.8 microg Se/g dry matter) was three times higher than in the stems (0.6 microg Se/g dry matter). Copyright 2002 Elsevier Science Ltd.

Two-compartmental population balance modeling of a pulsed spray fluidized bed granulation based on computational fluid dynamics (CFD) analysis.

PubMed

Liu, Huolong; Li, Mingzhong

2014-11-20

In this work a two-compartmental population balance model (TCPBM) was proposed to model a pulsed top-spray fluidized bed granulation. The proposed TCPBM considered the spatially heterogeneous granulation mechanisms of the granule growth by dividing the granulator into two perfectly mixed zones of the wetting compartment and drying compartment, in which the aggregation mechanism was assumed in the wetting compartment and the breakage mechanism was considered in the drying compartment. The sizes of the wetting and drying compartments were constant in the TCPBM, in which 30% of the bed was the wetting compartment and 70% of the bed was the drying compartment. The exchange rate of particles between the wetting and drying compartments was determined by the details of the flow properties and distribution of particles predicted by the computational fluid dynamics (CFD) simulation. The experimental validation has shown that the proposed TCPBM can predict evolution of the granule size and distribution within the granulator under different binder spray operating conditions accurately. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluating the biogas potential of the dry fraction from pretreatment of food waste from households.

PubMed

Murto, Marika; Björnsson, Lovisa; Rosqvist, Håkan; Bohn, Irene

2013-05-01

At the waste handling company NSR, Helsingborg, Sweden, the food waste fraction of source separated municipal solid waste is pretreated to obtain a liquid fraction, which is used for biogas production, and a dry fraction, which is at present incinerated. This pretreatment and separation is performed to remove impurities, however also some of the organic material is removed. The possibility of realising the methane potential of the dry fraction through batch-wise dry anaerobic digestion was investigated. The anaerobic digestion technique used was a two-stage process consisting of a static leach bed reactor and a methane reactor. Treatment of the dry fraction alone and in a mixture with structural material was tested to investigate the effect on the porosity of the leach bed. A tracer experiment was carried out to investigate the liquid flow through the leach beds, and this method proved useful in demonstrating a more homogenous flow through the leach bed when structural material was added. Addition of structural material to the dry fraction was needed to achieve a functional digestion process. A methane yield of 98 m3/ton was obtained from the dry fraction mixed with structural material after 76 days of digestion. This was in the same range as obtained in the laboratory scale biochemical methane potential test, showing that it was possible to extract the organic content in the dry fraction in this type of dry digestion system for the production of methane. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of radiation protraction on BED in the case of large fraction dose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuperman, V. Y.

2013-08-15

Purpose: To investigate the effect of radiation protraction on biologically effective dose (BED) in the case when dose per fraction is significantly greater than the standard dose of 2 Gy.Methods: By using the modified linear-quadratic model with monoexponential repair, the authors investigate the effect of long treatment times combined with dose escalation.Results: The dependences of the protraction factor and the corresponding BED on fraction time were determined for different doses per fraction typical for stereotactic radiosurgery (SRS) and stereotactic body radiation therapy (SBRT). In the calculations, the authors consider changes in the BED to the normal tissue under the conditionmore » of fixed BED to the target.Conclusion: The obtained results demonstrate that simultaneous increase in fraction time and dose per fraction can be beneficial for SRS and SBRT because of the related decrease in BED to normal structures while BED to the target is fixed.« less

Response of bed surface patchiness to reductions in sediment supply

NASA Astrophysics Data System (ADS)

Nelson, Peter A.; Venditti, Jeremy G.; Dietrich, William E.; Kirchner, James W.; Ikeda, Hiroshi; Iseya, Fujiko; Sklar, Leonard S.

2009-06-01

River beds are often arranged into patches of similar grain size and sorting. Patches can be distinguished into "free patches," which are zones of sorted material that move freely, such as bed load sheets; "forced patches," which are areas of sorting forced by topographic controls; and "fixed patches" of bed material rendered immobile through localized coarsening that remain fairly persistent through time. Two sets of flume experiments (one using bimodal, sand-rich sediment and the other using unimodal, sand-free sediment) are used to explore how fixed and free patches respond to stepwise reductions in sediment supply. At high sediment supply, migrating bed load sheets formed even in unimodal, sand-free sediment, yet grain interactions visibly played a central role in their formation. In both sets of experiments, reductions in supply led to the development of fixed coarse patches, which expanded at the expense of finer, more mobile patches, narrowing the zone of active bed load transport and leading to the eventual disappearance of migrating bed load sheets. Reductions in sediment supply decreased the migration rate of bed load sheets and increased the spacing between successive sheets. One-dimensional morphodynamic models of river channel beds generally are not designed to capture the observed variability, but should be capable of capturing the time-averaged character of the channel. When applied to our experiments, a 1-D morphodynamic model (RTe-bookAgDegNormGravMixPW.xls) predicted the bed load flux well, but overpredicted slope changes and was unable to predict the substantial variability in bed load flux (and load grain size) because of the migration of mobile patches. Our results suggest that (1) the distribution of free and fixed patches is primarily a function of sediment supply, (2) the dynamics of bed load sheets are primarily scaled by sediment supply, (3) channels with reduced sediment supply may inherently be unable to transport sediment uniformly across their width, and (4) cross-stream variability in shear stress and grain size can produce potentially large errors in width-averaged sediment flux calculations.

7 CFR 3201.15 - Bedding, bed linens, and towels.

Code of Federal Regulations, 2014 CFR

2014-01-01

... group of woven cloth products used as coverings on a bed. Bedding includes products such as blankets, bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding. (3) Towels are woven cloth products used primarily for drying and wiping. (b) Minimum biobased content. The...

7 CFR 2902.15 - Bedding, bed linens, and towels.

Code of Federal Regulations, 2011 CFR

2011-01-01

... group of woven cloth products used as coverings on a bed. Bedding includes products such as blankets, bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding. (3) Towels are woven cloth products used primarily for drying and wiping. (b) Minimum biobased content. The...

7 CFR 3201.15 - Bedding, bed linens, and towels.

Code of Federal Regulations, 2012 CFR

2012-01-01

... group of woven cloth products used as coverings on a bed. Bedding includes products such as blankets, bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding. (3) Towels are woven cloth products used primarily for drying and wiping. (b) Minimum biobased content. The...

7 CFR 3201.15 - Bedding, bed linens, and towels.

Code of Federal Regulations, 2013 CFR

2013-01-01

... group of woven cloth products used as coverings on a bed. Bedding includes products such as blankets, bedspreads, comforters, and quilts. (2) Bed linens are woven cloth sheets and pillowcases used in bedding. (3) Towels are woven cloth products used primarily for drying and wiping. (b) Minimum biobased content. The...

Thermal insulation and SIDS-an investigation of selected 'Eastern' and 'Western' infant bedding combinations.

PubMed

Wilson, C A; Chu, M S

2005-08-01

Differences in the incidence of SIDS between 'Western' and 'Eastern' countries has been attributed to cultural practices, which may affect the infants care and thermal environment. The purpose of this work was to estimate for selected 'commonly' used bedding, sleep positions and practices in Japan, Korea and New Zealand, the intrinsic 'dry' thermal resistance of bedding. Insulation levels are also discussed in the context of published information about the thermal environment in which the bedding is likely to be used. Selected Japanese, Korean and New Zealand bedding was loosely tucked over an infant manikin in the lateral, prone and supine sleep positions. Thickness in use was measured, and intrinsic 'dry' thermal resistance estimated using the Wilson Laing model which accommodates the effect on insulation of the three-dimensional arrangement of bedding combinations during use. Thickness of under- and upper-bedding varied among countries with thickness and estimated 'dry' thermal resistance of the upper-bedding affected by the type/combination of bedding and the infants sleep position. Insulation levels are discussed in relation to environmental conditions within and among countries and between seasons. Further information on thermal environments, bedding combinations used and care practices within both Asian and Western countries is needed. 'Eastern' infants appear likely to be generally covered in bedding combinations of greater insulation than those used to cover 'Western' infants in comparable seasons. Differences existed between insulation of the Japanese and Korean bedding combinations investigated. Lower rates of SIDS apparent in 'Asian' populations do not appear attributable to use of lower levels of bedding insulation only.

Removal of heavy metals from acid mine drainage using chicken eggshells in column mode.

PubMed

Zhang, Ting; Tu, Zhihong; Lu, Guining; Duan, Xingchun; Yi, Xiaoyun; Guo, Chuling; Dang, Zhi

2017-03-01

Chicken eggshells (ES) as alkaline sorbent were immobilized in a fixed bed to remove typical heavy metals from acid mine drainage (AMD). The obtained breakthrough curves showed that the breakthrough time increased with increasing bed height, but decreased with increasing flow rate and increasing particle size. The Thomas model and bed depth service time model could accurately predict the bed dynamic behavior. At a bed height of 10 cm, a flow rate of 10 mL/min, and with ES particle sizes of 0.18-0.425 mm, for a multi-component heavy metal solution containing Cd 2+ , Pb 2+ and Cu 2+ , the ES capacities were found to be 1.57, 146.44 and 387.51 mg/g, respectively. The acidity of AMD effluent clearly decreased. The ES fixed-bed showed the highest removal efficiency for Pb with a better adsorption potential. Because of the high concentration in AMD and high removal efficiency in ES fixed-bed of iron ions, iron floccules (Fe 2 (OH) 2 CO 3 ) formed and obstructed the bed to develop the overall effectiveness. The removal process was dominated by precipitation under the alkaline reaction of ES, and the co-precipitation of heavy metals with iron ions. The findings of this work will aid in guiding and optimizing pilot-scale application of ES to AMD treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Effects of wind speed on drying processes of fuelbeds composed of Mongolian oak broad-leaves.

PubMed

Zhang, Li Bin; Sun, Ping; Jin, Sen

2016-11-18

Water desorption processes of fuel beds with Mongolian oak broad-leaves were observed under conditions with various wind speeds but nearly constant air temperature and humidity. The effects of wind speed on drying coefficients of fuel beds with various moisture contents were analyzed. Three phases of drying process, namely high initial moisture content (>75%) of phase 1, transition state of phase 2, and equilibrium phase III could be identified. During phase 1, water loss rate under higher wind speed was higher than that under lower wind speed. Water loss rate under higher wind speed was lower than that under lower wind speed during phase 2. During phase 3, water loss rates under different wind speeds were similar. The wind effects decreased with the decrease of fuel moisture. The drying coefficient of the Mongolian oak broad-leaves fuel beds was affected by wind speed and fuel bed compactness, and the interaction between these two factors. The coefficient increased with wind speed roughly in a monotonic cubic polynomial form.

Evaluation of conductive cooling of lactating dairy cows under controlled environmental conditions.

PubMed

Ortiz, X A; Smith, J F; Rojano, F; Choi, C Y; Bruer, J; Steele, T; Schuring, N; Allen, J; Collier, R J

2015-03-01

Cooling systems used to reduce heat stress in dairy operations require high energy, water usage, or both. Steady increases in electricity costs and reduction of water availability and an increase in water usage regulations require evaluation of passive cooling systems to cool cows and reduce use of water and electricity. A study was conducted to evaluate the use of heat exchangers buried 25 cm below the surface as components in a conductive system for cooling cows. Six cows were housed in environmentally controlled rooms with tie-stall beds, which were equipped with a heat exchanger and filled with 25 cm of either sand or dried manure. Beds were connected to supply and return lines and individually controlled. Two beds (one per each kind of bedding material) constituted a control group (water off), and the other 4 (2 sand and 2 dried manure) used water at 7°C passing through the heat exchangers (water on). The experiment was divided in 2 periods of 40 d, and each period involved 3 repetitions of 3 different climates (hot and dry, thermo neutral, and hot and humid). Each cow was randomly assigned to a different treatment after each repetition was over. Sand bedding remained cooler than dried manure bedding in all environments and at all levels of cooling (water on or off). Bed temperatures were lower and heat flux higher during the bed treatment with sand and water on. We also detected a reduction in core body temperatures, respiration rates, rectal temperatures, and skin temperatures of those cows during the sand and water on treatment. Feed intake and milk yield numerically increased during the bed treatment with sand and water on for all climates. No major changes were observed in the lying time of cows or the composition of the milk produced. We conclude that use of heat exchangers is a viable adjunct to systems that employ fans, misters, and evaporative cooling methods to mitigate effects of heat stress on dairy cows. Sand was superior to dried manure as a bedding material in combination with heat exchangers. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Flow, turbulence, and drag associated with engineered log jams in a fixed-bed experimental channel

USDA-ARS?s Scientific Manuscript database

Engineered log jams (ELJs) have become attractive alternatives for river restoration and bank stabilization programs. Yet the effects of ELJs on turbulent flow and the fluid forces acting on the ELJs are not well known, and such information could inform design criteria. In this study, a fixed-bed ph...

An evaluation of fluid bed drying of aqueous granulations.

PubMed

Hlinak, A J; Saleki-Gerhardt, A

2000-01-01

The purpose of the work described was twofold: (a) to apply heat and mass balance approaches to evaluate the fluid bed drying cycle of an aqueous granulation, and (b) to determine the effect of the temperature and relative humidity of the drying air on the ability to meet a predetermined moisture content specification. Water content determinations were performed using Karl Fischer titration, and Computrac and Mark 1 moisture analyzers. The water vapor sorption isotherms were measured using a gravimetric moisture sorption apparatus with vacuum-drying capability. Temperature, relative humidity, and air flow were measured during the drying cycle of a production-scale fluid bed dryer. Heat and mass balance equations were used to calculate the evaporation rates. Evaporation rates calculated from heat and mass balance equations agreed well with the experimental data, whereas equilibrium moisture content values provided useful information for determination of the upper limit for inlet air humidity. Increasing the air flow rate and inlet temperature reduced the drying time through the effect on the primary driving force. As expected, additional drying of granules during the equilibration period did not show a significant impact on reducing the final moisture content of granules. Reducing the drying temperature resulted in measurement of higher equilibrium moisture content for the granules, which was in good agreement with the water vapor sorption data. Heat and mass balance equations can be used to successfully model the fluid bed drying cycle of aqueous granulations. The water vapor sorption characteristics of granules dictate the final moisture content at a given temperature and relative humidity.

Media arrangement impacts cell growth in anaerobic fixed-bed reactors treating sugarcane vinasse: Structured vs. randomic biomass immobilization.

PubMed

de Aquino, Samuel; Fuess, Lucas Tadeu; Pires, Eduardo Cleto

2017-07-01

This study reports on the application of an innovative structured-bed reactor (FVR) as an alternative to conventional packed-bed reactors (PBRs) to treat high-strength solid-rich wastewaters. Using the FVR prevents solids from accumulating within the fixed-bed, while maintaining the advantages of the biomass immobilization. The long-term operation (330days) of a FVR and a PBR applied to sugarcane vinasse under increasing organic loads (2.4-18.0kgCODm -3 day -1 ) was assessed, focusing on the impacts of the different media arrangements over the production and retention of biomass. Much higher organic matter degradation rates, as well as long-term operational stability and high conversion efficiencies (>80%) confirmed that the FVR performed better than the PBR. Despite the equivalent operating conditions, the biomass growth yield was different in both reactors, i.e., 0.095gVSSg -1 COD (FVR) and 0.066gVSSg -1 COD (PBR), indicating a clear control of the media arrangement over the biomass production in fixed-bed reactors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Conceptual process design and techno-economic assessment of ex situ catalytic fast pyrolysis of biomass: A fixed bed reactor implementation scenario for future feasibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dutta, Abhijit; Schaidle, Joshua A.; Humbird, David

Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid biofuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrolysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design reportmore » led by the National Renewable Energy Laboratory (NREL/TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suitable for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C–C coupling chemistry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C–C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition. Since this study is based on future projections, the impacts of uncertainties in the underlying assumptions are quantified via sensitivity analysis. As a result, this analysis indicates that catalyst researchers should prioritize by: carbon efficiency > catalyst cost > catalyst lifetime, after initially testing for basic operational feasibility.« less

Conceptual process design and techno-economic assessment of ex situ catalytic fast pyrolysis of biomass: A fixed bed reactor implementation scenario for future feasibility

DOE PAGES

Dutta, Abhijit; Schaidle, Joshua A.; Humbird, David; ...

2015-10-06

Ex situ catalytic fast pyrolysis of biomass is a promising route for the production of fungible liquid biofuels. There is significant ongoing research on the design and development of catalysts for this process. However, there are a limited number of studies investigating process configurations and their effects on biorefinery economics. Herein we present a conceptual process design with techno-economic assessment; it includes the production of upgraded bio-oil via fixed bed ex situ catalytic fast pyrolysis followed by final hydroprocessing to hydrocarbon fuel blendstocks. This study builds upon previous work using fluidized bed systems, as detailed in a recent design reportmore » led by the National Renewable Energy Laboratory (NREL/TP-5100-62455); overall yields are assumed to be similar, and are based on enabling future feasibility. Assuming similar yields provides a basis for easy comparison and for studying the impacts of areas of focus in this study, namely, fixed bed reactor configurations and their catalyst development requirements, and the impacts of an inline hot gas filter. A comparison with the fluidized bed system shows that there is potential for higher capital costs and lower catalyst costs in the fixed bed system, leading to comparable overall costs. The key catalyst requirement is to enable the effective transformation of highly oxygenated biomass into hydrocarbons products with properties suitable for blending into current fuels. Potential catalyst materials are discussed, along with their suitability for deoxygenation, hydrogenation and C–C coupling chemistry. This chemistry is necessary during pyrolysis vapor upgrading for improved bio-oil quality, which enables efficient downstream hydroprocessing; C–C coupling helps increase the proportion of diesel/jet fuel range product. One potential benefit of fixed bed upgrading over fluidized bed upgrading is catalyst flexibility, providing greater control over chemistry and product composition. Since this study is based on future projections, the impacts of uncertainties in the underlying assumptions are quantified via sensitivity analysis. As a result, this analysis indicates that catalyst researchers should prioritize by: carbon efficiency > catalyst cost > catalyst lifetime, after initially testing for basic operational feasibility.« less

Fixed bed column study for Cu (II) removal from aqueous solution using water hyacinth (Eichornia crassipes) biomass.

PubMed

Gandhimathi, R; Ramesh, S T; Yadu, Anubhav; Bharathi, K S

2013-07-01

This paper reports the results of the study on the performance of low-cost biosorbent water hyacinth (WH) in removing Cu (II) from aqueous solution. The adsorbent material adopted was found to be an efficient media for the removal of Cu (II) in continuous mode using fixed bed column. The column studies were conducted with 10 mg/L metal solution with a flow rate of 10 mL/min with different bed depths such as 10, 20 and 30 cm. The column design parameters like adsorption rate constant, adsorption capacity and minimum bed depth were calculated. It was found that, the adsorption capacity of copper ions by water hyacinth increased by increasing the bed depth and the contact time.

Fixed bed gasification for production of industrial fuel gas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1977-10-01

This report summarizes the results of technical and economic evaluations of six commercially available, fixed-bed coal gasification processes for the production of industrial fuel gas. The study was performed for DOE and is intended to assist industrial companies in exploring the feasibility of producing gaseous fuels for both retrofit and new industrial plant situations. The report includes a technical analysis of the physical configuration, performance capabilities, and commercial experiments to-date for both air-blown and oxygen-blown fixed bed gasifiers. The product gas from these gasifiers is analyzed economically for three different degrees of cleanliness: (1) hot raw gas, (2) dust-, tar-,more » and oil-free gas, and (3) dust-, tar-, oil-free and desulfurized gas. The evaluations indicate that low-Btu gases produced from fixed bed gasifiers constitute one of the most logical short-term solutions for helping ease the shortage of natural gas for industrial fuel applications because the technology is well-proven and has been utilized on a commercial scale for several decades both in this country and overseas; time from initiation of design to commercial operation is about two years; the technology is not complicated to construct, operate, or maintain; and a reliable supply of product gas can be generated on-site. The advantages and disadvantages of fixed bed gasification technology are listed. The cost of the low Btu gas is estimated at $2 to $4 per MM Btu depending on gas purity, cost of coal ($20 to $50 per ton) and a number of specified assumptions with respect to financing, reliability, etc. (LTN)« less

Modeling fixed and fluidized reactors for cassava starch Saccharification with immobilized enzyme

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zanin, G.M.; De Moraes, F.F.

1997-12-31

Cassava starch saccharification in fixed-and fluidized-bed reactors using immobilized enzyme was modeled in a previous paper using a simple model in which all dextrins were grouped in a single substrate. In that case, although good fit of the model to experimental data was obtained, physical inconsistency appeared as negative kinetic constants. In this work, a multisubstrate model, developed earlier for saccharification with free enzyme, is adapted for immobilized enzyme. This latter model takes into account the formation of intermediate substrates, which are dextrins competing for the catalytic site of the enzyme, reversibility of some reactions, inhibition by substrate and product,more » and the formation of isomaltose. Kinetic parameters to be used with this model were obtained from initial velocity saccharification tests using the immobilized enzyme and different liquefied starch concentrations. The new model was found to be valid for modeling both fixed- and fluidized-bed reactors. It did not present inconsistencies as the earlier one had and has shown that apparent glucose inhibition is about seven times higher in the fixed-bed than in fluidized-bed reactor. 13 refs., 5 figs., 1 tab.« less

Dry method for recycling iodine-loaded silver zeolite

DOEpatents

Thomas, Thomas R.; Staples, Bruce A.; Murphy, Llewellyn P.

1978-05-09

Fission product iodine is removed from a waste gas stream and stored by passing the gas stream through a bed of silver-exchanged zeolite until the zeolite is loaded with iodine, passing dry hydrogen gas through the bed to remove the iodine and regenerate the bed, and passing the hydrogen stream containing the hydrogen iodide thus formed through a lead-exchanged zeolite which adsorbs the radioactive iodine from the gas stream and permanently storing the lead-exchanged zeolite loaded with radioactive iodine.

Design and fabrication of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolytic oil production in Bangladesh

NASA Astrophysics Data System (ADS)

Aziz, Mohammad Abdul; Al-khulaidi, Rami Ali; Rashid, MM; Islam, M. R.; Rashid, MAN

2017-03-01

In this research, a development and performance test of a fixed-bed batch type pyrolysis reactor for pilot scale pyrolysis oil production was successfully completed. The characteristics of the pyrolysis oil were compared to other experimental results. A solid horizontal condenser, a burner for furnace heating and a reactor shield were designed. Due to the pilot scale pyrolytic oil production encountered numerous problems during the plant’s operation. This fixed-bed batch type pyrolysis reactor method will demonstrate the energy saving concept of solid waste tire by creating energy stability. From this experiment, product yields (wt. %) for liquid or pyrolytic oil were 49%, char 38.3 % and pyrolytic gas 12.7% with an operation running time of 185 minutes.

A green strategy for desorption of trihalomethanes adsorbed by humin and reuse of the fixed bed column.

PubMed

Cunha, G C; Romão, L P C; Santos, M C; Costa, A S; Alexandre, M R

2012-03-30

The objective of the present work was to develop a thermal desorption method for the removal of trihalomethanes (THM) adsorbed by humin, followed by multiple recycling of the fixed bed column in order to avoid excessive consumption of materials and reduce operating costs. The results obtained for adsorption on a fixed bed column confirmed the effectiveness of humin as an adsorbent, extracting between 45.9% and 90.1% of the total THM (TTHM). In none of the tests was the column fully saturated after 10h. Experiments involving thermal desorption were used to evaluate the potential of the technique for column regeneration. The adsorptive capacity of the humin bed increased significantly (p<0.05) between the first and fifth desorption cycle, by 18.9%, 18.1%, 24.2%, 20.2% and 24.2% for CHBr(3), CHBr(2)Cl, CHBrCl(2), CHCl(3) and TTHM, respectively. Copyright © 2011 Elsevier B.V. All rights reserved.

Fixed-bed biosorption of cadmium using immobilized Scenedesmus obliquus CNW-N cells on loofa (Luffa cylindrica) sponge.

PubMed

Chen, Bor-Yann; Chen, Chun-Yen; Guo, Wan-Qian; Chang, Hao-Wei; Chen, Wen-Ming; Lee, Duu-Jong; Huang, Chieh-Chen; Ren, Nan-Qi; Chang, Jo-Shu

2014-05-01

A continuous fixed-bed biosorption process was established for cadmium (Cd) removal by Scenedesmus obliquus CNW-N (isolated from southern Taiwan) cells immobilized onto loofa sponge. This immobilized-cell biosorption process allows better recovery and reusability of the microalgal biomass. The growth of microalgae on the matrix support with appropriate nutrient supplementation could enhance the overall metal removal activity. Major operating parameters (e.g., feeding flow rate, cycle number of medium replacement, and particle diameter of the sponge) were studied for treatability evaluation. The most promising cell growth on the sponge support was obtained at a flow rate of 0.284 bed volume (BV)/min, sponge particle diameter of 1 cm, and with one cycle of medium replacement. The performance of fixed-bed biosorption (adsorption capacity of 38.4 mg, breakthrough time at 15.5 h) was achieved at a flow rate of 5 ml/min with an influent concentration of 7.5 mg Cd/l. Copyright © 2014 Elsevier Ltd. All rights reserved.

Drying Beds. Sludge Treatment and Disposal Course #166. Instructor's Guide [and] Student Workbook.

ERIC Educational Resources Information Center

Klopping, Paul H.

Provided in this lesson is introductory material on sand and surfaced sludge drying beds. Typical construction and operation, proper maintenance, and safety procedures are considered. The lesson includes an instructor's guide and student workbook. The instructor's guide contains a description of the lesson, estimated presentation time,…

Biomass drying in a pulsed fluidized bed without inert bed particles

DOE PAGES

Jia, Dening; Bi, Xiaotao; Lim, C. Jim; ...

2016-08-29

Batch drying was performed in the pulsed fluidized bed with various species of biomass particles as an indicator of gas–solid contact efficiency and mass transfer rate under different operating conditions including pulsation duty cycle and particle size distribution. The fluidization of cohesive biomass particles benefited from the shorter opening time of pulsed gas flow and increased peak pressure drop. The presence of fines enhanced gas–solid contact of large and irregular biomass particles, as well as the mass transfer efficiency. A drying model based on two-phase theory was proposed, from which effective diffusivity was calculated for various gas flow rates, temperaturemore » and pulsation frequency. Intricate relationship was discovered between pulsation frequency and effective diffusivity, as mass transfer was deeply connected with the hydrodynamics. Effective diffusivity was also found to be proportional to gas flow rate and drying temperature. In conclusion, operating near the natural frequency of the system also favored drying and mass transfer.« less

Air-drying beds reduce the quantities of antibiotic resistance genes and class 1 integrons in residual municipal wastewater solids.

PubMed

Burch, Tucker R; Sadowsky, Michael J; LaPara, Timothy M

2013-09-03

This study investigated whether air-drying beds reduce antibiotic resistance gene (ARG) concentrations in residual municipal wastewater solids. Three laboratory-scale drying beds were operated for a period of nearly 100 days. Real-time PCR was used to quantify 16S rRNA genes, 16S rRNA genes specific to fecal bacteria (AllBac) and human fecal bacteria (HF183), the integrase gene of class 1 integrons (intI1), and five ARGs representing a cross-section of antibiotic classes and resistance mechanisms (erm(B), sul1, tet(A), tet(W), and tet(X)). Air-drying beds were capable of reducing all gene target concentrations by 1 to 5 orders of magnitude, and the nature of this reduction was consistent with both a net decrease in the number of bacterial cells and a lack of selection within the microbial community. Half-lives varied between 1.5 d (HF183) and 5.4 d (tet(X)) during the first 20 d of treatment. After the first 20 d of treatment, however, half-lives varied between 8.6 d (tet(X)) and 19.3 d (AllBac), and 16S rRNA gene, intI1, and sul1 concentrations did not change (P > 0.05). These results demonstrate that air-drying beds can reduce ARG and intI1 concentrations in residual municipal wastewater solids within timeframes typical of operating practices.

CFD Analysis to Calculate the Optimal Air Velocity in Drying Green Tea Process Using Fluidized Bed Dryer

NASA Astrophysics Data System (ADS)

Yohana, Eflita; Nugraha, Afif Prasetya; Diana, Ade Eva; Mahawan, Ilham; Nugroho, Sri

2018-02-01

Tea processing is basically distinguished into three types which black tea, green tea, and oolong tea. Green tea is processed by heating and drying the leaves. Green tea factories in Indonesia are generally using the process of drying by panning the leaves. It is more recommended to use the fluidization process to speed up the drying process as the quality of the tea can be maintained. Bubbling fluidization is expected to occur in this research. It is a process of bubbles are formed in the fluidization. The effectiveness of the drying process in a fluidized bed dryer machine needs to be improved by using a CFD simulation method to proof that umf < u < ut, where the average velocity value is limited by the minimum and the maximum velocity of the calculation the experimental data. The minimum and the maximum velocity value of the fluidization is 0.96 m/s and 8.2 m/s. The result of the simulation obtained that the average velocity of the upper bed part is 1.81 m/s. From the results obtained, it can be concluded that the calculation and the simulation data is in accordance with the condition of bubbling fluidization in fluidized bed dryer.

Adsorptive Water Removal from Dichloromethane and Vapor-Phase Regeneration of a Molecular Sieve 3A Packed Bed

PubMed Central

2017-01-01

The drying of dichloromethane with a molecular sieve 3A packed bed process is modeled and experimentally verified. In the process, the dichloromethane is dried in the liquid phase and the adsorbent is regenerated by water desorption with dried dichloromethane product in the vapor phase. Adsorption equilibrium experiments show that dichloromethane does not compete with water adsorption, because of size exclusion; the pure water vapor isotherm from literature provides an accurate representation of the experiments. The breakthrough curves are adequately described by a mathematical model that includes external mass transfer, pore diffusion, and surface diffusion. During the desorption step, the main heat transfer mechanism is the condensation of the superheated dichloromethane vapor. The regeneration time is shortened significantly by external bed heating. Cyclic steady-state experiments demonstrate the feasibility of this novel, zero-emission drying process. PMID:28539701

ASPEN simulation of a fixed-bed integrated gasification combined-cycle power plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stone, K.R.

1986-03-01

A fixed-bed integrated gasification combined-cycle (IGCC) power plant has been modeled using the Advanced System for Process ENgineering (ASPEN). The ASPEN simulation is based on a conceptual design of a 509-MW IGCC power plant that uses British Gas Corporation (BGC)/Lurgi slagging gasifiers and the Lurgi acid gas removal process. The 39.3-percent thermal efficiency of the plant that was calculated by the simulation compares very favorably with the 39.4 percent that was reported by EPRI. The simulation addresses only thermal performance and does not calculate capital cost or process economics. Portions of the BGC-IGCC simulation flowsheet are based on the SLAGGERmore » fixed-bed gasifier model (Stefano May 1985), and the Kellogg-Rust-Westinghouse (KRW) iGCC, and the Texaco-IGCC simulations (Stone July 1985) that were developed at the Department of Energy (DOE), Morgantown Energy Technology Center (METC). The simulation runs in 32 minutes of Central Processing Unit (CPU) time on the VAX-11/780. The BGC-IGCC simulation was developed to give accurate mass and energy balances and to track coal tars and environmental species such as SO/sub x/ and NO/sub x/ for a fixed-bed, coal-to-electricity system. This simulation is the third in a series of three IGCC simulations that represent fluidized-bed, entrained-flow, and fixed-bed gasification processes. Alternate process configurations can be considered by adding, deleting, or rearranging unit operation blocks. The gasifier model is semipredictive; it can properly respond to a limited range of coal types and gasifier operating conditions. However, some models in the flowsheet are based on correlations that were derived from the EPRI study, and are therefore limited to coal types and operating conditions that are reasonably close to those given in the EPRI design. 4 refs., 7 figs., 2 tabs.« less

Enhanced removal of sulfonamide antibiotics by KOH-activated anthracite coal: Batch and fixed-bed studies.

PubMed

Zuo, Linzi; Ai, Jing; Fu, Heyun; Chen, Wei; Zheng, Shourong; Xu, Zhaoyi; Zhu, Dongqiang

2016-04-01

The presence of sulfonamide antibiotics in aquatic environments poses potential risks to human health and ecosystems. In the present study, a highly porous activated carbon was prepared by KOH activation of an anthracite coal (Anth-KOH), and its adsorption properties toward two sulfonamides (sulfamethoxazole and sulfapyridine) and three smaller-sized monoaromatics (phenol, 4-nitrophenol and 1,3-dinitrobenzene) were examined in both batch and fixed-bed adsorption experiments to probe the interplay between adsorbate molecular size and adsorbent pore structure. A commercial powder microporous activated carbon (PAC) and a commercial mesoporous carbon (CMK-3) possessing distinct pore properties were included as comparative adsorbents. Among the three adsorbents Anth-KOH exhibited the largest adsorption capacities for all test adsorbates (especially the two sulfonamides) in both batch mode and fixed-bed mode. After being normalized by the adsorbent surface area, the batch adsorption isotherms of sulfonamides on PAC and Anth-KOH were displaced upward relative to the isotherms on CMK-3, likely due to the micropore-filling effect facilitated by the microporosity of adsorbents. In the fixed-bed mode, the surface area-normalized adsorption capacities of Anth-KOH for sulfonamides were close to that of CMK-3, and higher than that of PAC. The irregular, closed micropores of PAC might impede the diffusion of the relatively large-sized sulfonamide molecules and in turn led to lowered fixed-bed adsorption capacities. The overall superior adsorption of sulfonamides on Anth-KOH can be attributed to its large specific surface area (2514 m(2)/g), high pore volume (1.23 cm(3)/g) and large micropore sizes (centered at 2.0 nm). These findings imply that KOH-activated anthracite coal is a promising adsorbent for the removal of sulfonamide antibiotics from aqueous solution. Copyright © 2016 Elsevier Ltd. All rights reserved.

Fluid bed material transfer method

DOEpatents

Pinske, Jr., Edward E.

1994-01-01

A fluidized bed apparatus comprising a pair of separated fluid bed enclosures, each enclosing a fluid bed carried on an air distributor plate supplied with fluidizing air from below the plate. At least one equalizing duct extending through sidewalls of both fluid bed enclosures and flexibly engaged therewith to communicate the fluid beds with each other. The equalizing duct being surrounded by insulation which is in turn encased by an outer duct having expansion means and being fixed between the sidewalls of the fluid bed enclosures.

Competitive adsorption of furfural and phenolic compounds onto activated carbon in fixed bed column.

PubMed

Sulaymon, Abbas H; Ahmed, Kawther W

2008-01-15

For a multicomponent competitive adsorption of furfural and phenolic compounds, a mathematical model was builtto describe the mass transfer kinetics in a fixed bed column with activated carbon. The effects of competitive adsorption equilibrium constant, axial dispersion, external mass transfer, and intraparticle diffusion resistance on the breakthrough curve were studied for weakly adsorbed compound (furfural) and strongly adsorbed compounds (parachlorophenol and phenol). Experiments were carried out to remove the furfural and phenolic compound from aqueous solution. The equilibrium data and intraparticle diffusion coefficients obtained from separate experiments in a batch adsorber, by fitting the experimental data with theoretical model. The results show that the mathematical model includes external mass transfer and pore diffusion using nonlinear isotherms and provides a good description of the adsorption process for furfural and phenolic compounds in a fixed bed adsorber.

Post-combustion CO2 capture with activated carbons using fixed bed adsorption

NASA Astrophysics Data System (ADS)

Al Mesfer, Mohammed K.; Danish, Mohd; Fahmy, Yasser M.; Rashid, Md. Mamoon

2018-03-01

In the current work, the capturing of carbon dioxide from flue gases of post combustion emission using fixed bed adsorption has been carried out. Two grades of commercial activated carbon (sorbent-1 and sorbent-2) were used as adsorbent. Feed consisting of CO2 and N2 mixture was used for carrying out the adsorption. The influence of bed temperature, feed rate, equilibrium partial pressure and initial % CO2 in feed were considered for analyzing adsorption-desorption process. It was found that the total adsorption-desorption cycle time decreases with increased column temperature and feed rates. The time required to achieve the condition of bed saturation decreases with increased bed temperature and feed rates. The amount of CO2 adsorbed/Kg of the adsorbent declines with increased bed temperature with in studied range for sorbent-1 and sorbent-2. It was suggested that the adsorption capacity of the both the sorbents increases with increased partial pressure of the gas.

Evaluation of the Parameters and Conditions of Process in the Ethylbenzene Dehydrogenation with Application of Permselective Membranes to Enhance Styrene Yield.

PubMed

Araújo, Paulo Jardel P; Leite, Manuela Souza; Ravagnani, Teresa M Kakuta

2016-01-01

Styrene is an important monomer in the manufacture of thermoplastic. Most of it is produced by the catalytic dehydrogenation of ethylbenzene. In this process that depends on reversible reactions, the yield is usually limited by the establishment of thermodynamic equilibrium in the reactor. The styrene yield can be increased by using a hybrid process, with reaction and separation simultaneously. It is proposed using permselective composite membrane to remove hydrogen and thus suppress the reverse and secondary reactions. This paper describes the simulation of a dehydrogenation process carried out in a tubular fixed-bed reactor wrapped in a permselective composite membrane. A mathematical model was developed, incorporating the various mass transport mechanisms found in each of the membrane layers and in the catalytic fixed bed. The effects of the reactor feed conditions (temperature, steam-to-oil ratio, and the weight hourly space velocity), the fixed-bed geometry (length, diameter, and volume), and the membrane geometry (thickness of the layers) on the styrene yield were analyzed. These variables were used to determine experimental conditions that favour the production of styrene. The simulation showed that an increase of 40.98% in the styrene yield, compared to a conventional fixed-bed process, could be obtained by wrapping the reactor in a permselective composite membrane.

Anaerobic treatment of winery wastewater in fixed bed reactors.

PubMed

Ganesh, Rangaraj; Rajinikanth, Rajagopal; Thanikal, Joseph V; Ramanujam, Ramamoorty Alwar; Torrijos, Michel

2010-06-01

The treatment of winery wastewater in three upflow anaerobic fixed-bed reactors (S9, S30 and S40) with low density floating supports of varying size and specific surface area was investigated. A maximum OLR of 42 g/l day with 80 +/- 0.5% removal efficiency was attained in S9, which had supports with the highest specific surface area. It was found that the efficiency of the reactors increased with decrease in size and increase in specific surface area of the support media. Total biomass accumulation in the reactors was also found to vary as a function of specific surface area and size of the support medium. The Stover-Kincannon kinetic model predicted satisfactorily the performance of the reactors. The maximum removal rate constant (U(max)) was 161.3, 99.0 and 77.5 g/l day and the saturation value constant (K(B)) was 162.0, 99.5 and 78.0 g/l day for S9, S30 and S40, respectively. Due to their higher biomass retention potential, the supports used in this study offer great promise as media in anaerobic fixed bed reactors. Anaerobic fixed-bed reactors with these supports can be applied as high-rate systems for the treatment of large volumes of wastewaters typically containing readily biodegradable organics, such as the winery wastewater.

Batch and fixed-bed biosorption of Cd(II) from aqueous solution using immobilized Pleurotus ostreatus spent substrate.

PubMed

Jin, Yu; Teng, Chunying; Yu, Sumei; Song, Tao; Dong, Liying; Liang, Jinsong; Bai, Xin; Liu, Xuesheng; Hu, Xiaojing; Qu, Juanjuan

2018-01-01

To prevent the blockage in a continuous fix-bed system, Pleurotus Ostreatus spent substrate (POSS), a composite agricultural waste, was immobilized into granular adsorbents (IPOSS) with polymeric matrix, and used to remove Cd(II) from synthetic wastewater in batch experiment as well as in continuous fixed-bed column system. In batch experiment, higher pH, temperature and Cd(II) initial concentration were conducive to a higher biosorption capacity, and the maximum biosorption capacity reached up to 87.2 mg/g at Cd(II) initial concentration of 200 mg/L, pH 6 and 25 °C. The biosorption of Cd(II) onto IPOSS followed the Langmuir isotherm model with the maximum adsorption capacity(q max ) of 100 mg/g. The biosorption was an endothermic reaction and a spontaneous process based on positive value of ΔH 0 and negative value of ΔG 0 . In fixed-bed column system, higher bed depth, lower flow rate and influent Cd(II) concentration led to a longer breakthrough and exhaustion time, and the best performance (equilibrium uptake (q e ) of 14.4 mg, breakthrough time at 31 h and exhaustion time at 78 h) was achieved at a bed depth of 110 cm, a flow rate of 1.2 L/h and an influent concentration of 100 mg/L. Furthermore, regeneration experiment revealed a good reusability of IPOSS with 0.1 M HNO 3 as eluting agent during three cycles of adsorption and desorption. Cd(II) biosorption onto IPOSS mainly relied on a chemical process including ion exchange and complexation or coordination revealed by SEM-EDX, FTIR and XRD analysis. Copyright © 2017. Published by Elsevier Ltd.

Hexagonal boron nitride catalyst in a fixed-bed reactor for exothermic propane oxidation dehydrogenation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tian, Jinshu; Lin, Jinhan; Xu, Mingliang

Hexagonal boron nitride (h-BN) with high thermal conductivity is potentially an effective catalyst for highly exothermic propane oxidative dehydrogenation (ODH) reaction. Here, we report our experimental and theoretic studies of such a catalyst for propane ODH in a fixed-bed reactor. Based on the computational fluid dynamics calculation (CFD) results, the catalyst bed temperature increases by less than 1°C in the h-BN catalyst bed which is much smaller than that (8°C) in the VO x/γ-Al 2O 3 catalyst bed at a similar propane conversion (25%) using a micro-tubular reactor with a diameter of 6 mm. Even in an industrially relevant reactormore » with an inner diameter of 60 mm, a uniform temperature profile can still be maintained using the h-BN catalyst bed due to its excellent thermal conductivity as opposed to a temperature gradient of 47°C in the VO x/γ-Al 2O 3 catalyst bed. The results reported here provide useful information for potential application of h-BN catalyst in propane ODH.« less

Hexagonal boron nitride catalyst in a fixed-bed reactor for exothermic propane oxidation dehydrogenation

DOE PAGES

Tian, Jinshu; Lin, Jinhan; Xu, Mingliang; ...

2018-04-17

Hexagonal boron nitride (h-BN) with high thermal conductivity is potentially an effective catalyst for highly exothermic propane oxidative dehydrogenation (ODH) reaction. Here, we report our experimental and theoretic studies of such a catalyst for propane ODH in a fixed-bed reactor. Based on the computational fluid dynamics calculation (CFD) results, the catalyst bed temperature increases by less than 1°C in the h-BN catalyst bed which is much smaller than that (8°C) in the VO x/γ-Al 2O 3 catalyst bed at a similar propane conversion (25%) using a micro-tubular reactor with a diameter of 6 mm. Even in an industrially relevant reactormore » with an inner diameter of 60 mm, a uniform temperature profile can still be maintained using the h-BN catalyst bed due to its excellent thermal conductivity as opposed to a temperature gradient of 47°C in the VO x/γ-Al 2O 3 catalyst bed. The results reported here provide useful information for potential application of h-BN catalyst in propane ODH.« less

Sludge dewatering and stabilization in drying reed beds: characterization of three full-scale systems in Catalonia, Spain.

PubMed

Uggetti, Enrica; Llorens, Esther; Pedescoll, Anna; Ferrer, Ivet; Castellnou, Roger; García, Joan

2009-09-01

Optimization of sludge management can help reducing sludge handling costs in wastewater treatment plants. Sludge drying reed beds appear as a new and alternative technology which has low energy requirements, reduced operating and maintenance costs, and causes little environmental impact. The objective of this work was to evaluate the efficiency of three full-scale drying reed beds in terms of sludge dewatering, stabilization and hygienisation. Samples of influent sludge and sludge accumulated in the reed beds were analysed for pH, Electrical Conductivity, Total Solids (TS), Volatile Solids (VS), Chemical Oxygen Demand, Biochemical Oxygen Demand, nutrients (Total Kjeldahl Nitrogen (TKN) and Total Phosphorus (TP)), heavy metals and faecal bacteria indicators (Escherichiacoli and Salmonella spp.). Lixiviate samples were also collected. There was a systematic increase in the TS concentration from 1-3% in the influent to 20-30% in the beds, which fits in the range obtained with conventional dewatering technologies. Progressive organic matter removal and sludge stabilization in the beds was also observed (VS concentration decreased from 52-67% TS in the influent to 31-49% TS in the beds). Concentration of nutrients of the sludge accumulated in the beds was quite low (TKN 2-7% TS and TP 0.04-0.7% TS), and heavy metals remained below law threshold concentrations. Salmonella spp. was not detected in any of the samples, while E. coli concentration was generally lower than 460MPN/g in the sludge accumulated in the beds. The studied systems demonstrated a good efficiency for sludge dewatering and stabilization in the context of small remote wastewater treatment plants.

Dry formulations of the biocontrol agent Candida sake CPA-1 using fluidised bed drying to control the main postharvest diseases on fruits.

PubMed

Carbó, Anna; Torres, Rosario; Usall, Josep; Fons, Estanislau; Teixidó, Neus

2017-08-01

The biocontrol agent Candida sake CPA-1 is effective against several diseases. Consequently, the optimisation of a dry formulation of C. sake to improve its shelf life and manipulability is essential for increasing its potential with respect to future commercial applications. The present study aimed to optimise the conditions for making a dry formulation of C. sake using a fluidised bed drying system and then to determine the shelf life of the optimised formulation and its efficacy against Penicillium expansum on apples. The optimal conditions for the drying process were found to be 40 °C for 45 min and the use of potato starch as the carrier significantly enhanced the viability. However, none of the protective compounds tested increased the viability of the dried cells. A temperature of 25 °C for 10 min in phosphate buffer was considered as the optimum condition to recover the dried formulations. The dried formulations should be stored at 4 °C and air-packaged; moreover, shelf life assays indicated good results after 12 months of storage. The formulated products maintained their biocontrol efficacy. A fluidised bed drying system is a suitable process for dehydrating C. sake cells; moreover, the C. sake formulation is easy to pack, store and transport, and is a cost-effective process. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Comparison of three different wastewater sludge and their respective drying processes: Solar, thermal and reed beds - Impact on organic matter characteristics.

PubMed

Collard, Marie; Teychené, Benoit; Lemée, Laurent

2017-12-01

Drying process aims at minimising the volume of wastewater sludge (WWS) before disposal, however it can impact sludge characteristics. Due to its high content in organic matter (OM) and lipids, sludge are mainly valorised by land farming but can also be considered as a feedstock for biodiesel production. As sludge composition is a major parameter for the choice of disposal techniques, the objective of this study was to determine the influence of the drying process. To reach this goal, three sludges obtained from solar, reed beds and thermal drying processes were investigated at the global and molecular scales. Before the drying step the sludges presented similar physico-chemical (OM content, elemental analysis, pH, infrared spectra) characteristics and lipid contents. A strong influence of the drying process on lipids and humic-like substances contents was observed through OM fractionation. Thermochemolysis-GCMS of raw sludge and lipids revealed similar molecular content mainly constituted with steroids and fatty acids. Molecular changes were noticeable for thermal drying through differences in branched to linear fatty acids ratio. Finally the thermal drying induced a weakening of OM whereas the solar drying led to a complexification. These findings show that smooth drying processes such as solar or reed-beds are preferable for amendment production whereas thermal process leads to pellets with a high lipid content which could be considered for fuel production. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of wood-based materials in beef bedded manure packs: 1. Effect on ammonia, total reduced sulfide, and greenhouse gas concentrations

USDA-ARS?s Scientific Manuscript database

The objectives of this study were to determine the effect of using corn stover or three different wood-based bedding materials (kiln-dried pine wood chips, dry cedar chips, or green cedar chips) on airborne concentrations of ammonia (NH3), total reduced sulfur (TRS), carbon dioxide (CO2), methane (C...

Use of radiation protraction to escalate biologically effective dose to the treatment target

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuperman, V. Y.; Spradlin, G. S.; Department of Mathematics, Embry-Riddle University, Daytona Beach, Florida 32114

2011-12-15

Purpose: The aim of this study is to evaluate how simultaneously increasing fraction time and dose per fraction affect biologically effective dose for the target (BED{sub tar}) while biologically effective dose for the normal tissue (BED{sub nt}) is fixed. Methods: In this investigation, BED{sub tar} and BED{sub nt} were studied by assuming mono-exponential repair of sublethal damage with tissue dependent repair half-time. Results: Our results demonstrate that under certain conditions simultaneously increasing fraction time and dose per fraction result in increased BED{sub tar} while BED{sub nt} is fixed. The dependence of biologically effective dose on fraction time is influenced bymore » the dose rate. In this investigation we analytically determined time-varying dose rate R-tilde which minimizes BED. Changes in BED with fraction time were compared for constant dose rate and for R-tilde. Conclusions: A number of recent experimental and theoretical studies have demonstrated that slow delivery of radiation (known as radiation protraction) leads to reduced therapeutic effect because of increased repair of sublethal damage. In contrast, our analysis shows that under certain conditions simultaneously increasing fraction time and dose per fraction are radiobiologically advantageous.« less

Batch and fixed bed adsorption of levofloxacin on granular activated carbon from date (Phoenix dactylifera L.) stones by KOH chemical activation.

PubMed

Darweesh, Teeba M; Ahmed, Muthanna J

2017-03-01

Granular activated carbon (KAC) was prepared from abundant Phoenix dactylifera L. stones by microwave- assisted KOH activation. The characteristics of KAC were tested by pore analyses, scanning electron microscopy (SEM) and Fourier transforms infrared spectroscopy (FTIR). The adsorption behavior of levofloxacin (LEV) antibiotic on KAC with surface area of 817m 2 /g and pore volume of 0.638cm 3 /g were analyzed using batch and fixed bed systems. The equilibrium data collected by batch experiments were well fitted with Langmuir compared to Freundlich and Temkin isotherms. The effect of flow rate (0.5-1.5ml/min), bed height (15-25cm), and initial LEV concentration (75-225mg/l) on the behavior of breakthrough curves was explained. The fixed bed analysis showed the better correlation of breakthrough data by both Thomas and Yoon-Nelson models. High LEV adsorption capacity of 100.3mg/g was reported on KAC, thus being an efficient adsorbent for antibiotic pollutants to protect ecological systems. Copyright © 2017 Elsevier B.V. All rights reserved.

Separation and purification of fructooligosaccharides on a zeolite fixed-bed column.

PubMed

Kuhn, Raquel Cristine; Mazutti, Marcio Antonio; Maugeri Filho, Francisco

2014-04-01

Fructooligosaccharides (FOS), a well-known prebiotic product, are obtained by enzymatic synthesis and consist of a mixture of mono- and disaccharides. In this work, a methodology for their separation and purification was developed using a zeolite fixed-bed column. The effects of column temperature (40-60°C), eluent flow rate (0.10-0.14 mL/min), injected to bed volume percent ratio (2.6-5.1%), and ethanol concentration in the eluent (40-60%, v/v) were investigated using a fractionary factorial design (2(4-1)), having the separation efficiency and purity as target responses. Additional experiments were performed as well, where the temperature and ethanol concentration were studied in a central composite design (2(2)). In this work, the zeolite fixed-bed column was shown to be a good alternative for FOS purification, allowing a FOS purity of 90% and separation efficiency of 6.86 between FOS and glucose, using an eluent at 45°C with 60% ethanol concentration. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optimization of the Carbon Dioxide Removal Assembly (CDRA-4EU) in Support of the International Space System and Advanced Exploration Systems

NASA Technical Reports Server (NTRS)

Knox, James C.; Stanley, Christine M.

2015-01-01

The Life Support Systems Project (LSSP) under the Advanced Exploration Systems (AES) program builds upon the work performed under the AES Atmosphere Resource Recovery and Environmental Monitoring (ARREM) project focusing on the numerous technology development areas. The Carbon Dioxide (CO2) removal and associated air drying development efforts are focused on improving the current state-of-the-art system on the International Space Station (ISS) utilizing fixed beds of sorbent pellets by seeking more robust pelletized sorbents, evaluating structured sorbents, and examining alternate bed configurations to improve system efficiency and reliability. A component of the CO2 removal effort utilizes a virtual Carbon Dioxide Removal Assembly, revision 4 (CDRA-4) test bed to test a large number of potential operational configurations with independent variations in flow rate, cycle time, heater ramp rate, and set point. Initial ground testing will provide prerequisite source data and provide baseline data in support of the virtual CDRA. Once the configurations with the highest performance and lowest power requirements are determined by the virtual CDRA, the results will be confirmed by testing these configurations with the CDRA-4EU ground test hardware. This paper describes the initial ground testing of select configurations. The development of the virtual CDRA under the AES-LSS Project will be discussed in a companion paper.

Effect of filter media thickness on the performance of sand drying beds used for faecal sludge management.

PubMed

Manga, M; Evans, B E; Camargo-Valero, M A; Horan, N J

2016-12-01

The effect of sand filter media thickness on the performance of faecal sludge (FS) drying beds was determined in terms of: dewatering time, contaminant load removal efficiency, solids generation rate, nutrient content and helminth eggs viability in the dried sludge. A mixture of ventilated improved pit latrine sludge and septage in the ratio 1:2 was dewatered using three pilot-scale sludge drying beds with sand media thicknesses of 150, 250 and 350 mm. Five dewatering cycles were conducted and monitored for each drying bed. Although the 150 mm filter had the shortest average dewatering time of 3.65 days followed by 250 mm and 350 mm filters with 3.83 and 4.02 days, respectively, there was no significant difference (p > 0.05) attributable to filter media thickness configurations. However, there was a significant difference for the percolate contaminant loads in the removal and recovery efficiency of suspended solids, total solids, total volatile solids, nitrogen species, total phosphorus, chemical oxygen demand, dissolved chemical oxygen demand and biochemical oxygen demand, with the highest removal efficiency for each parameter achieved by the 350 mm filter. There were also significant differences in the nutrient content (NPK) and helminth eggs viability of the solids generated by the tested filters. Filtering media configurations similar to 350 mm have the greatest potential for optimising nutrient recovery from FS.

Formulating food protein-stabilized indomethacin nanosuspensions into pellets by fluid-bed coating technology: physical characterization, redispersibility, and dissolution.

PubMed

He, Wei; Lu, Yi; Qi, Jianping; Chen, Lingyun; Yin, Lifang; Wu, Wei

2013-01-01

Drug nanosuspensions are very promising for enhancing the dissolution and bioavailability of drugs that are poorly soluble in water. However, the poor stability of nanosuspensions, reflected in particle growth, aggregation/agglomeration, and change in crystallinity state greatly limits their applications. Solidification of nanosuspensions is an ideal strategy for addressing this problem. Hence, the present work aimed to convert drug nanosuspensions into pellets using fluid-bed coating technology. Indomethacin nanosuspensions were prepared by the precipitation-ultrasonication method using food proteins (soybean protein isolate, whey protein isolate, β-lactoglobulin) as stabilizers. Dried nanosuspensions were prepared by coating the nanosuspensions onto pellets. The redispersibility, drug dissolution, solid-state forms, and morphology of the dried nanosuspensions were evaluated. The mean particle size for the nanosuspensions stabilized using soybean protein isolate, whey protein isolate, and β-lactoglobulin was 588 nm, 320 nm, and 243 nm, respectively. The nanosuspensions could be successfully layered onto pellets with high coating efficiency. Both the dried nanosuspensions and nanosuspensions in their original amorphous state and not influenced by the fluid-bed coating drying process could be redispersed in water, maintaining their original particle size and size distribution. Both the dried nanosuspensions and the original drug nanosuspensions showed similar dissolution profiles, which were both much faster than that of the raw crystals. Fluid-bed coating technology has potential for use in the solidification of drug nanosuspensions.

40 CFR 63.1413 - Compliance demonstration procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... measured and used to establish the outlet organic HAP concentration. (iii) For a carbon adsorption system that regenerates the carbon bed directly onsite in the control device, such as a fixed-bed adsorber... time, number and capacity of carbon beds, type and working capacity of activated carbon used for carbon...

40 CFR 63.1413 - Compliance demonstration procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... measured and used to establish the outlet organic HAP concentration. (iii) For a carbon adsorption system that regenerates the carbon bed directly onsite in the control device, such as a fixed-bed adsorber... time, number and capacity of carbon beds, type and working capacity of activated carbon used for carbon...

Degradation of anionic surfactants during drying of UASBR sludges on sand drying beds.

PubMed

Mungray, Arvind Kumar; Kumar, Pradeep

2008-09-01

Anionic surfactant (AS) concentrations in wet up-flow anaerobic sludge blanket reactor (UASBR) sludges from five sewage treatment plants (STPs) were found to range from 4480 to 9,233 mg kg(-1)dry wt. (average 7,347 mg kg(-1)dry wt.) over a period of 18 months. After drying on sand drying beds (SDBs), AS in dried-stabilized sludges averaged 1,452 mg kg(-1)dry wt., a reduction of around 80%. The kinetics of drying followed simple first-order reduction of moisture with value of drying constant (k(d))=0.051 d(-1). Reduction of AS also followed first-order kinetics. AS degradation rate constant (k(AS)) was found to be 0.034 d(-1) and half-life of AS as 20 days. The order of rates of removal observed was k(d)>k(AS)>k(COD)>k(OM) (drying >AS degradation>COD reduction>organic matter reduction). For the three applications of dried-stabilized sludges (soil, agricultural soil, grassland), values of risk quotient (RQ) were found to be <1, indicating no risk.

Odorous volatile organic compounds, Escherichia coli, and nutrient concentrations when kiln-dried pine chips and corn stover bedding are used in beef bedded manure packs

USDA-ARS?s Scientific Manuscript database

Pine (Pinus spp.) bedding has been shown to lower the concentration of odorous volatile organic compounds (VOCs) and pathogenic bacteria compared with corn (Zea mays L.) stover bedding, but availability and cost limit the use of pine bedding in cattle confinement facilities. The objectives of this s...

Fıxed bed slow pyrolysıs of bıomass solıd waste for bıo-char

NASA Astrophysics Data System (ADS)

Islam, M. N.; Ali, M. H.; Ahmad, I.

2017-06-01

Biomass solid waste in the form of rice husk particle is pyrolyzed in a fixed bed pyrolysis reactor. The reactor is made of stainless steel with dimensions of 76 mm in diameter and 90 cm in length. Rice husk is collected locally from Brunei-Muara district of Brunei Darussalam which is processed for pyrolysis. The particles are selected in the millimeter range. It is oven-dried at 105°C for 6 hours after being air-dried prior to pyrolysis. The reactor bed is heated by means of saw-dust in a biomass source heater. A temperature range of 390-410°C is maintained with an apperent vapor residence time of 30 min. Nitrogen gas is passed through the reactor system to make the atmosphere inert. A water-cooled condenser is used to derive bio-oil from the condensable vapors. The system is subjected to pyrolysis for a running time of 60 min. The products obtained are solid bio-char, liquid bio-oil and pyrolytic bio-gases. The solid char yield is found to be 45 by weight of solid biomass feedstock and the liquid product yield is found to be 29 by weight of solid biomass feedstock. The rest is gas flared into the atmosphere. The bio-char is retained in the reactor and collected at the end of the experimental run. The bio-char is found to be black in color retaining its original shape. The bio-char product is subjected to energy analysis for its higher heating value (HHV) by means of an oxygen bomb calorimeter. It is found to be 20.3 MJ/kg. The density of the bio-char is found to be 238.5 kg/m3 with an energy density of 4.85 GJ/m3.

Digestion of high rate activated sludge coupled to biochar formation for soil improvement in the tropics.

PubMed

Nansubuga, Irene; Banadda, Noble; Ronsse, Frederik; Verstraete, Willy; Rabaey, Korneel

2015-09-15

High rate activated sludge (HRAS) is well-biodegradable sludge enabling energy neutrality of wastewater treatment plants via anaerobic digestion. However, even through successful digestion a notable residue still remains. Here we investigated whether this residue can be converted to biochar, for its use as a fertilizer or as a solid fuel, and assessed its characteristics and overall process efficiency. In a first phase, HRAS was anaerobicaly digested under mesophilic conditions at a sludge retention time of 20 days. HRAS digested well (57.9 ± 6.2% VS degradation) producing on average 0.23 ± 0.04 L CH4 per gram VS fed. The digestate particulates were partially air-dried to mimic conditions used in developing countries, and subsequently converted to biochar by fixed-bed slow pyrolysis at a residence time of 15 min and at highest heating temperatures (HHT) of 300 °C, 400 °C and 600 °C. Subsequently, the produced chars were characterized by proximate analysis, CHN-elemental analysis, pH in solution and bomb calorimetry for higher heating value. The yield and volatile matter decreased with increasing HHT while ash content and fixed carbon increased with increasing HHT. The produced biochar showed properties optimal towards soil amendment when produced at a temperature of 600 °C with values of 5.91 wt%, 23.75 wt%, 70.35% on dry basis (db) and 0.44 for volatile matter, fixed carbon, ash content and H/C ratio, respectively. With regard to its use for energy purposes, the biochar represented a lower calorific value than the dried HRAS digestate likely due to high ash content. Based on these findings, it can be concluded that anaerobic digestion of HRAS and its subsequent biochar formation at HHT of 600 °C represents an attractive route for sludge management in tropic settings like in Uganda, coupling carbon capture to energy generation, carbon sequestration and nutrient recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of the Parameters and Conditions of Process in the Ethylbenzene Dehydrogenation with Application of Permselective Membranes to Enhance Styrene Yield

PubMed Central

Araújo, Paulo Jardel P.; Leite, Manuela Souza; Kakuta Ravagnani, Teresa M.

2016-01-01

Styrene is an important monomer in the manufacture of thermoplastic. Most of it is produced by the catalytic dehydrogenation of ethylbenzene. In this process that depends on reversible reactions, the yield is usually limited by the establishment of thermodynamic equilibrium in the reactor. The styrene yield can be increased by using a hybrid process, with reaction and separation simultaneously. It is proposed using permselective composite membrane to remove hydrogen and thus suppress the reverse and secondary reactions. This paper describes the simulation of a dehydrogenation process carried out in a tubular fixed-bed reactor wrapped in a permselective composite membrane. A mathematical model was developed, incorporating the various mass transport mechanisms found in each of the membrane layers and in the catalytic fixed bed. The effects of the reactor feed conditions (temperature, steam-to-oil ratio, and the weight hourly space velocity), the fixed-bed geometry (length, diameter, and volume), and the membrane geometry (thickness of the layers) on the styrene yield were analyzed. These variables were used to determine experimental conditions that favour the production of styrene. The simulation showed that an increase of 40.98% in the styrene yield, compared to a conventional fixed-bed process, could be obtained by wrapping the reactor in a permselective composite membrane. PMID:27069982

Differences in fundamental and functional properties of HPMC co-processed fillers prepared by fluid-bed coating and spray drying.

PubMed

Dong, QianQian; Zhou, MiaoMiao; Lin, Xiao; Shen, Lan; Feng, Yi

2018-07-01

This study aimed to develop novel co-processed tablet fillers based on the principle of particle engineering for direct compaction and to compare the characteristics of co-processed products obtained by fluid-bed coating and co-spray drying, respectively. Water-soluble mannitol and water-insoluble calcium carbonate were selected as representative fillers for this study. Hydroxypropyl methylcellulose (HPMC), serving as a surface property modifier, was distributed on the surface of primary filler particles via the two co-processing methods. Both fundamental and functional properties of the products were comparatively investigated. The results showed that functional properties of the fillers, like flowability, compactibility, and drug-loading capacity, were effectively improved by both co-processing methods. However, fluid-bed coating showed greater advantages over co-spray drying in some aspects, which was mainly attributed to the remarkable differences in some fundamental properties of co-processed powders, like particle size, surface topology, and particle structure. For example, the more irregular surface and porous structure induced by fluid-bed coating could contribute to better compaction properties and lower lubricant sensitivity due to the increasing contact area and mechanical interlocking between particles under pressure. More effective surface distribution of HPMC during fluid-bed coating was also a contributor. In addition, such a porous agglomerate structure could also reduce the separation of drug and excipients after mixing, resulting in the improvement in drug loading capacity and tablet uniformity. In summary, fluid-bed coating appears to be more promising for co-processing than spray drying in some aspects, and co-processed excipients produced by it have a great prospect for further investigations and development. Copyright © 2018 Elsevier B.V. All rights reserved.

Use of natural clinoptilolite for the removal of lead, copper and zinc in fixed bed column.

PubMed

Stylianou, Marinos A; Hadjiconstantinou, Michalis P; Inglezakis, Vasilis J; Moustakas, Konstantinos G; Loizidou, Maria D

2007-05-08

This work deals with the removal of lead, copper and zinc from aqueous solutions by using natural zeolite (clinoptilolite). Fixed bed experiments were performed, using three different volumetric flow rates of 5, 7 and 10bed volume/h, under a total normality of 0.01N, at initial pH of 4 and ambient temperature (25 degrees C). The removal efficiency increased when decreasing the flow rate and the following selectivity series was found: Pb(2+)>Zn(2+)> or =Cu(2+). Conductivity measurements showed that lead removal follows mainly ion exchange mechanism, while copper and zinc removal follows ion exchange and sorption mechanism as well.

Ammoniacal nitrogen and COD removal from semi-aerobic landfill leachate using a composite adsorbent: fixed bed column adsorption performance.

PubMed

Halim, Azhar Abdul; Aziz, Hamidi Abdul; Johari, Megat Azmi Megat; Ariffin, Kamar Shah; Adlan, Mohd Nordin

2010-03-15

The performance of a carbon-mineral composite adsorbent used in a fixed bed column for the removal of ammoniacal nitrogen and aggregate organic pollutant (COD), which are commonly found in landfill leachate, was evaluated. The breakthrough capacities for ammoniacal nitrogen and COD adsorption were 4.46 and 3.23 mg/g, respectively. Additionally, the optimum empty bed contact time (EBCT) was 75 min. The column efficiency for ammoniacal nitrogen and COD adsorption using fresh adsorbent was 86.4% and 92.6%, respectively, and these values increased to 90.0% and 93.7%, respectively, after the regeneration process. (c) 2009 Elsevier B.V. All rights reserved.

An experimental investigation of the effect of walls on gas-liquid flows through fixed particle beds.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cooper, Marcia A.; Cote, Raymond O.; Torczynski, John Robert

The effect of particle diameter on downward co-current gas-liquid flow through a fixed bed of particles confined within a cylindrical column is investigated. Several hydrodynamic regimes that depend strongly on the properties of the gas stream, the liquid stream, and the packed particle bed are known to exist within these systems. This experimental study focuses on characterizing the effect of wall confinement on these hydrodynamic regimes as the diameter d of the spherical particles becomes comparable to the column diameter D (or D/d becomes order-unity). The packed bed consists of polished, solid, spherical, monodisperse particles (beads) with mean diameter inmore » the range of 0.64-2.54 cm. These diameters yield D/d values between 15 and 3.75, so this range overlaps and extends the previously investigated range for two-phase flow, Measurements of the pressure drop across the bed and across the pulses are obtained for varying gas and liquid flow rates.« less

Isolated thermocouple amplifier system for stirred fixed-bed gasifier

DOEpatents

Fasching, George E.

1992-01-01

A sensing system is provided for determining the bed temperature profile of the bed of a stirred, fixed-bed gasifier including a plurality of temperature sensors for sensing the bed temperature at different levels, a transmitter for transmitting data based on the outputs of the sensors to a remote operator's station, and a battery-based power supply. The system includes an isolation amplifier system comprising a plurality of isolation amplifier circuits for amplifying the outputs of the individual sensors. The isolation amplifier circuits each comprise an isolation operational amplifier connected to a sensor; a first "flying capacitor" circuit for, in operation, controlling the application of power from the power supply to the isolation amplifier; an output sample and hold circuit connected to the transmitter; a second "flying capacitor" circuit for, in operation, controlling the transfer of the output of the isolation amplifier to the sample and hold circuit; and a timing and control circuit for activating the first and second capacitor circuits in a predetermined timed sequence.

Grand Forks - East Grand Forks Urban Water Resources Study. Wastewater Management Appendix.

DTIC Science & Technology

1981-07-01

SLUIGES FROM AEROBIC DIGESTION . 2. LOADING RATE OF 20 LB/FT 2/YR APPLICABLE TO BIOLOGICAL SLUDGES FROM ANAEROBIC DIGESTION. 3. EXPECTED PERFORMANCE...plant size as follows: Sludge Handling Facilities Flow Range Biological Sludge Lime Sludge Flow <_ 3 MCD Flotation thickening, Gravity thicken & aerobic ... digestion , & drying beds. drying beds. 3 MGD < Mot; < 10 MGD Flotation thickening, Gravity thicken & anaerobic digestion, & vacuum filter. vacuum

[Prediction model of health workforce and beds in county hospitals of Hunan by multiple linear regression].

PubMed

Ling, Ru; Liu, Jiawang

2011-12-01

To construct prediction model for health workforce and hospital beds in county hospitals of Hunan by multiple linear regression. We surveyed 16 counties in Hunan with stratified random sampling according to uniform questionnaires,and multiple linear regression analysis with 20 quotas selected by literature view was done. Independent variables in the multiple linear regression model on medical personnels in county hospitals included the counties' urban residents' income, crude death rate, medical beds, business occupancy, professional equipment value, the number of devices valued above 10 000 yuan, fixed assets, long-term debt, medical income, medical expenses, outpatient and emergency visits, hospital visits, actual available bed days, and utilization rate of hospital beds. Independent variables in the multiple linear regression model on county hospital beds included the the population of aged 65 and above in the counties, disposable income of urban residents, medical personnel of medical institutions in county area, business occupancy, the total value of professional equipment, fixed assets, long-term debt, medical income, medical expenses, outpatient and emergency visits, hospital visits, actual available bed days, utilization rate of hospital beds, and length of hospitalization. The prediction model shows good explanatory and fitting, and may be used for short- and mid-term forecasting.

Fixed bed sorption of phosphorus from wastewater using iron oxide-based media derived from acid mine drainage

USGS Publications Warehouse

Sibrell, Philip L.; Tucker, T.W.

2012-01-01

Phosphorus (P) releases to the environment have been implicated in the eutrophication of important water bodies worldwide. Current technology for the removal of P from wastewaters consists of treatment with aluminum (Al) or iron (Fe) salts, but is expensive. The neutralization of acid mine drainage (AMD) generates sludge rich in Fe and Al oxides that has hitherto been considered a waste product, but these sludges could serve as an economical adsorption media for the removal of P from wastewaters. Therefore, we have evaluated an AMD-derived media as a sorbent for P in fixed bed sorption systems. The homogenous surface diffusion model (HSDM) was used to analyze fixed bed test data and to determine the value of related sorption parameters. The surface diffusion modulus Ed was found to be a useful predictor of sorption kinetics. Values of Ed < 0.2 were associated with early breakthrough of P, while more desirable S-shaped breakthrough curves resulted when 0.2 < Ed < 0.5. Computer simulations of the fixed bed process with the HSDM confirmed that if Ed was known, the shape of the breakthrough curve could be calculated. The surface diffusion coefficient D s was a critical factor in the calculation of Ed and could be estimated based on the sorption test conditions such as media characteristics, and influent flow rate and concentration. Optimal test results were obtained with a relatively small media particle size (average particle radius 0.028 cm) and resulted in 96 % removal of P from the influent over 46 days of continuous operation. These results indicate that fixed bed sorption of P would be a feasible option for the utilization of AMD residues, thus helping to decrease AMD treatment costs while at the same time ameliorating the impacts of P contamination.

Mechanistic modelling of fluidized bed drying processes of wet porous granules: a review.

PubMed

Mortier, Séverine Thérèse F C; De Beer, Thomas; Gernaey, Krist V; Remon, Jean Paul; Vervaet, Chris; Nopens, Ingmar

2011-10-01

Fluidized bed dryers are frequently used in industrial applications and also in the pharmaceutical industry. The general incentives to develop mechanistic models for pharmaceutical processes are listed, and our vision on how this can particularly be done for fluidized bed drying processes of wet granules is given. This review provides a basis for future mechanistic model development for the drying process of wet granules in pharmaceutical processes. It is intended for a broad audience with a varying level of knowledge on pharmaceutical processes and mathematical modelling. Mathematical models are powerful tools to gain process insight and eventually develop well-controlled processes. The level of detail embedded in such a model depends on the goal of the model. Several models have therefore been proposed in the literature and are reviewed here. The drying behaviour of one single granule, a porous particle, can be described using the continuum approach, the pore network modelling method and the shrinkage of the diameter of the wet core approach. As several granules dry at a drying rate dependent on the gas temperature, gas velocity, porosity, etc., the moisture content of a batch of granules will reside in a certain interval. Population Balance Model (ling) (PBM) offers a tool to describe the distribution of particle properties which can be of interest for the application. PBM formulation and solution methods are therefore reviewed. In a fluidized bed, the granules show a fluidization pattern depending on the geometry of the gas inlet, the gas velocity, characteristics of the particles, the dryer design, etc. Computational Fluid Dynamics (CFD) allows to model this behaviour. Moreover, turbulence can be modelled using several approaches: Reynolds-averaged Navier-Stokes Equations (RANS) or Large Eddy Simulation (LES). Another important aspect of CFD is the choice between the Eulerian-Lagrangian and the Eulerian-Eulerian approach. Finally, the PBM and CFD frameworks can be integrated, to describe the evolution of the moisture content of granules during fluidized bed drying. Copyright © 2011 Elsevier B.V. All rights reserved.

Evaluating the biogas potential of the dry fraction from pretreatment of food waste from households

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murto, Marika, E-mail: marika.murto@biotek.lu.se; Björnsson, Lovisa, E-mail: lovisa.bjornsson@miljo.lth.se; Environmental and Energy Systems Studies, Lund University, P.O. Box 118, SE-221 00 Lund

2013-05-15

Highlights: ► A novel approach for biogas production from a waste fraction that today is incinerated. ► Biogas production is possible in spite of the impurities of the waste. ► Tracer studies are applied in a novel way. ► Structural material is needed to improve the flow pattern of the waste. ► We provide a solution to biological treatment for the complex waste fraction. - Abstract: At the waste handling company NSR, Helsingborg, Sweden, the food waste fraction of source separated municipal solid waste is pretreated to obtain a liquid fraction, which is used for biogas production, and a drymore » fraction, which is at present incinerated. This pretreatment and separation is performed to remove impurities, however also some of the organic material is removed. The possibility of realising the methane potential of the dry fraction through batch-wise dry anaerobic digestion was investigated. The anaerobic digestion technique used was a two-stage process consisting of a static leach bed reactor and a methane reactor. Treatment of the dry fraction alone and in a mixture with structural material was tested to investigate the effect on the porosity of the leach bed. A tracer experiment was carried out to investigate the liquid flow through the leach beds, and this method proved useful in demonstrating a more homogenous flow through the leach bed when structural material was added. Addition of structural material to the dry fraction was needed to achieve a functional digestion process. A methane yield of 98 m{sup 3}/ton was obtained from the dry fraction mixed with structural material after 76 days of digestion. This was in the same range as obtained in the laboratory scale biochemical methane potential test, showing that it was possible to extract the organic content in the dry fraction in this type of dry digestion system for the production of methane.« less

Formulating food protein-stabilized indomethacin nanosuspensions into pellets by fluid-bed coating technology: physical characterization, redispersibility, and dissolution

PubMed Central

He, Wei; Lu, Yi; Qi, Jianping; Chen, Lingyun; Yin, Lifang; Wu, Wei

2013-01-01

Background Drug nanosuspensions are very promising for enhancing the dissolution and bioavailability of drugs that are poorly soluble in water. However, the poor stability of nanosuspensions, reflected in particle growth, aggregation/agglomeration, and change in crystallinity state greatly limits their applications. Solidification of nanosuspensions is an ideal strategy for addressing this problem. Hence, the present work aimed to convert drug nanosuspensions into pellets using fluid-bed coating technology. Methods Indomethacin nanosuspensions were prepared by the precipitation-ultrasonication method using food proteins (soybean protein isolate, whey protein isolate, β-lactoglobulin) as stabilizers. Dried nanosuspensions were prepared by coating the nanosuspensions onto pellets. The redispersibility, drug dissolution, solid-state forms, and morphology of the dried nanosuspensions were evaluated. Results The mean particle size for the nanosuspensions stabilized using soybean protein isolate, whey protein isolate, and β-lactoglobulin was 588 nm, 320 nm, and 243 nm, respectively. The nanosuspensions could be successfully layered onto pellets with high coating efficiency. Both the dried nanosuspensions and nanosuspensions in their original amorphous state and not influenced by the fluid-bed coating drying process could be redispersed in water, maintaining their original particle size and size distribution. Both the dried nanosuspensions and the original drug nanosuspensions showed similar dissolution profiles, which were both much faster than that of the raw crystals. Conclusion Fluid-bed coating technology has potential for use in the solidification of drug nanosuspensions. PMID:23983465

Studies on convective drying of `Ameclyae' Opuntia ficus-indica seeds and its effect on the quality of extracted oil based on its α-tocopherol content

NASA Astrophysics Data System (ADS)

Hassini, Lamine; Bettaieb, Emna; Motri, Samia; Desmorieux, Hélène

2018-02-01

The aim of this work is to model the thin layer convective drying kinetics of `Ameclyae' prickly pear seed variety and to evaluate the effects of drying conditions on the quality of extracted seed oil, specifically α-tocopherol content. Drying experiments were carried on following a full 23 factorial design using a vertical drying tunnel. The study is restricted to a particular particle size and a particular seed bed of height 0.5 cm, of effective porosity around 0.4 and of initial moisture content on dry basis equal to 1.2 (± 0.01) kg/kg. The temperature range was 45 to 70 °C, relative humidity range was 15-30% and air velocity was 1 and 2 m/s. The experimental drying curves were fitted to different semi-theoretical drying models proposed in the literature. The Midilli-Kucuk model was found with satisfaction describing the seed air drying curves with a correlation coefficient of 0.999 and a standard error of 0.01. For each drying condition, the extraction of fixed oil seeds was performed at cold using liquid/solid separation method. The oil quality was evaluated on the basis of the α-tocopherol content. The α-tocopherol was identified and quantified by high-performance liquid chromatography (HPLC-UV). According to the experimental results, it was found that drying air velocity is the most important factor influencing the concentration of α-tocopherol, whereas the effects of temperature and relative humidity were lower. The increase of the velocity from 1 m/s to 2 m/s reduced the α-tocopherol concentration by about 25%. The convective drying of thin layer of seeds at soft air conditions, drying temperature of 45 °C, relative humidity of 15% and air velocity of 1 m/s give the optimal quality of extracted oil in terms of α-tocopherol content. Characterization of the morphologic structure of seeds was also performed by SEM.

Fixed-bed adsorption study of methylene blue onto pyrolytic tire char

NASA Astrophysics Data System (ADS)

Makrigianni, Vassiliki; Giannakas, Aris; Papadaki, Maria; Albanis, Triantafyllos; Konstantinou, Ioannis

2016-04-01

In this work, the adsorption efficiency of acid treated pyrolytic tire char to cationic methylene blue (MB) dye adsorption from aqueous solutions was investigated by fixed-bed adsorption column experiments. The effects of the initial dye concentration (10 - 40 mg L-1) and feed flow rate (50 - 150 mL min -1) with a fixed bed height (15 cm) were studied in order to determine the breakthrough characteristics of the adsorption system. The Adams-Bohart, Yoon-Nelson and Thomas model were applied to the adsorption of MB onto char at different operational conditions to predict the breakthrough curves and to determine the characteristic parameters of the column. The results showed that the maximum adsorbed quantities decreased with increasing flow rate and increased with increasing initial MB concentration. Breakthrough time and exhaustion time increased with decreasing inlet dye concentration and flow rate. In contrast with Adams-Bohart model, Yoon-Nelson model followed by Thomas model were found more suitable to describe the fixed-bed adsorption of methylene blue by char. The correlation coefficient values R2 for both models at different operating conditions are higher than 0.9 and the low average relative error values provided very good fittings of experimental data at different operating conditions. Higher adsorption capacity of 3.85 mg g -1 was obtained at 15 cm of adsorbent bed height, flow rate of 100 mL min -1and initial MB concentration of 40 mg L-1. Although that activated carbons exhibited higher adsorption capacities in the literature, acid-treated pyrolytic tire char was found to be considerably efficient adsorbent for the removal of MB dye column taking into account the advantages of the simpler production process compared to activated carbons, as well as, the availability of waste tire feedstock and concurrent waste tire management.

Leaching of FGD Byproducts Using a CSTX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kairies, C.L.; Schroeder, K.T.; Cardone, C.R.

2005-09-01

Leaching studies of coal utilization byproducts (CUB) are often performed to determine the compatibility of the material in a particular end-use or disposal environment. Typically, these studies are conducted using either a batch or a fixed-bed column technique. Fixed-bed columns offer the advantage of a continuous flow of effluent that provides elution profiles with changing elution volume and pH. Unfortunately, clogs can form in fixed-bed leaching columns, either because of cementitious properties of the material itself, such as is seen for fluidized bed combustion (FBC) fly ash, or because of precipitate formation, such as can occur when a high-calcium ashmore » is subjected to sulfate-containing leachates. Also, very fine-grained materials, such as gypsum, do not provide sufficient permeability for study in a fixed-bed column. A continuous, stirred-tank extractor (CSTX) is being used as an alternative technique that can provide the elution profile of column leaching but without the low permeability problems. The CSTX has been successfully employed in the leaching of flue gas desulfurization products that would not be sufficiently permeable under traditional column leaching conditions. The results indicate that the leaching behavior depends on a number of factors, including (but not limited to) solubility and neutralization capacity of the mineral phases present, sorption properties of these phases, behavior of the solubilized material in the tank, and the type of species in solution. In addition, leaching to near-exhaustion of a wallboard produced from FGD gypsum has allowed the isolation of a highly adsorptive phase. This phase appears to be present in at least some FGD gypsums and accounts for the immobilization of trace metals such as arsenic, cobalt, lead, and mercury.« less

Drying characteristics and quality of rough rice under infrared radiation heating

USDA-ARS?s Scientific Manuscript database

Infrared (IR) radiation heating could provide high heating rate and rapid moisture removal for rough rice drying. The objective of this research was to investigate the effect of the drying bed thickness on drying characteristics and quality of rough rice subjected to IR heating. Samples of freshly ...

Empirical correlations for axial dispersion coefficient and Peclet number in fixed-bed columns.

PubMed

Rastegar, Seyed Omid; Gu, Tingyue

2017-03-24

In this work, a new correlation for the axial dispersion coefficient was obtained using experimental data in the literature for axial dispersion in fixed-bed columns packed with particles. The Chung and Wen correlation, the De Ligny correlation are two popular empirical correlations. However, the former lacks the molecular diffusion term and the latter does not consider bed voidage. The new axial dispersion coefficient correlation in this work was based on additional experimental data in the literature by considering both molecular diffusion and bed voidage. It is more comprehensive and accurate. The Peclet number correlation from the new axial dispersion coefficient correlation on the average leads to 12% lower Peclet number values compared to the values from the Chung and Wen correlation, and in many cases much smaller than those from the De Ligny correlation. Copyright © 2017 Elsevier B.V. All rights reserved.

Adsorption characteristics of methylene blue onto agricultural wastes lotus leaf in bath and column modes.

PubMed

Han, Xiuli; Wang, Wei; Ma, Xiaojian

2011-01-01

The adsorption potential of lotus leaf to remove methylene blue (MB) from aqueous solution was investigated in batch and fixed-bed column experiments. Langmuir, Freundlich, Temkin and Koble-Corrigan isotherm models were employed to discuss the adsorption behavior. The results of analysis indicated that the equilibrium data were perfectly represented by Temkin isotherm and the Langmuir saturation adsorption capacity of lotus leaf was found to be 239.6 mg g(-1) at 303 K. In fixed-bed column experiments, the effects of flow rate, influent concentration and bed height on the breakthrough characteristics of adsorption were discussed. The Thomas and the bed-depth/service time (BDST) models were applied to the column experimental data to determine the characteristic parameters of the column adsorption. The two models were found to be suitable to describe the dynamic behavior of MB adsorbed onto the lotus leaf powder column.

Monitoring fluidized bed drying of pharmaceutical granules.

PubMed

Briens, Lauren; Bojarra, Megan

2010-12-01

Placebo granules consisting of lactose monohydrate, corn starch, and polyvinylpyrrolidone were prepared using de-ionized water in a high-shear mixer and dried in a conical fluidized bed dryer at various superficial gas velocities. Acoustic, vibration, and pressure data obtained over the course of drying was analyzed using various statistical, frequency, fractal, and chaos techniques. Traditional monitoring methods were also used for reference. Analysis of the vibration data showed that the acceleration levels decreased during drying and reached a plateau once the granules had reached a final moisture content of 1–2 wt.%; this plateau did not differ significantly between superficial gas velocities, indicating a potential criterion to support drying endpoint identification. Acoustic emissions could not reliably identify the drying endpoint. However, high kurtosis values of acoustic emissions measured in the filtered air exhaust corresponded to high entrainment rates. This could be used for process control to adjust the fluidization gas velocity to allow drying to continue rapidly while minimizing entrainment and possible product losses.

Investigation on the quality of bio-oil produced through fast pyrolysis of biomass-polymer waste mixture

NASA Astrophysics Data System (ADS)

Jourabchi, S. A.; Ng, H. K.; Gan, S.; Yap, Z. Y.

2016-06-01

A high-impact poly-styrene (HIPS) was mixed with dried and ground coconut shell (CS) at equal weight percentage. Fast pyrolysis was carried out on the mixture in a fixed bed reactor over a temperature range of 573 K to 1073 K, and a nitrogen (N2) linear velocity range of 7.8x10-5 m/s to 6.7x10-2 m/s to produce bio-oil. Heat transfer and fluid dynamics of the pyrolysis process inside the reactor was visualised by using Computational Fluid Dynamics (CFD). The CFD modelling was validated by experimental results and they both indicated that at temperature of 923 K and N2 linear velocity of 7.8x10-5 m/s, the maximum bio-oil yield of 52.02 wt% is achieved.

Drop Breakup in Fixed Bed Flows as Model Stochastic Flow Fields

NASA Technical Reports Server (NTRS)

Shaqfeh, Eric S. G.; Mosler, Alisa B.; Patel, Prateek

1999-01-01

We examine drop breakup in a class of stochastic flow fields as a model for the flow through fixed fiber beds and to elucidate the general mechanisms whereby drops breakup in disordered, Lagrangian unsteady flows. Our study consists of two parallel streams of investigation. First, large scale numerical simulations of drop breakup in a class of anisotropic Gaussian fields will be presented. These fields are generated spectrally and have been shown in a previous publication to be exact representations of the flow in a dilute disordered bed of fibers if close interactions between the fibers and the drops are dynamically unimportant. In these simulations the drop shape is represented by second and third order small deformation theories which have been shown to be excellent for the prediction of drop breakup in steady strong flows. We show via these simulations that the mechanisms of drop breakup in these flows are quite different than in steady flows. The predominant mechanism of breakup appears to be very short lived twist breakups. Moreover, the occurrence of breakup events is poorly predicted by either the strength of the local flow in which the drop finds itself at breakup, or the degree of deformation that the drop achieves prior to breakup. It is suggested that a correlation function of both is necessary to be predictive of breakup events. In the second part of our research experiments are presented where the drop deformation and breakup in PDMS/polyisobutylene emulsions is considered. We consider very dilute emulsions such that coalescence is unimportant. The flows considered are simple shear and the flow through fixed fiber beds. Turbidity, small angle light scattering, dichroism and microscopy are used to interrogate the drop deformation process in both flows. It is demonstrated that breakup at very low capillary numbers occurs in both flows but larger drop deformation occurs in the fixed bed flow. Moreover, it is witnessed that breakup in the bed occurs continuously during flow and apparently with uniform probability through the bed length. The drop deformations witnessed in our experiments are larger than those predicted by the numerical simulations, and future plans to investigate these differences are discussed.

Tips for Travel

EPA Pesticide Factsheets

Avoid bringing bed bugs home by taking precautions when traveling such as inspecting bedding and luggage racks in hotel rooms, and upon returning home unpacking directly into a washing machine and dry at high temperatures.

Removal of furan and phenolic compounds from simulated biomass hydrolysates by batch adsorption and continuous fixed-bed column adsorption methods.

PubMed

Lee, Sang Cheol; Park, Sunkyu

2016-09-01

It has been proposed to remove all potential inhibitors and sulfuric acid in biomass hydrolysates generated from dilute-acid pretreatment of biomass, based on three steps of sugar purification process. This study focused on its first step in which furan and phenolic compounds were selectively removed from the simulated hydrolysates using activated charcoal. Batch adsorption experiments demonstrated that the affinity of activated charcoal for each component was highest in the order of vanillic acid, 4-hydroxybenzoic acid, furfural, acetic acid, sulfuric acid, and xylose. The affinity of activated charcoal for furan and phenolic compounds proved to be significantly higher than that of the other three components. Four separation strategies were conducted with a combination of batch adsorption and continuous fixed-bed column adsorption methods. It was observed that xylose loss was negligible with near complete removal of furan and phenolic compounds, when at least one fixed-bed column adsorption was implemented in the strategy. Copyright © 2016 Elsevier Ltd. All rights reserved.

Co-pyrolysis characteristics of sawdust and coal blend in TGA and a fixed bed reactor.

PubMed

Park, Dong Kyoo; Kim, Sang Done; Lee, See Hoon; Lee, Jae Goo

2010-08-01

Co-pyrolysis characteristics of sawdust and coal blend were determined in TGA and a fixed bed reactor. The yield and conversion of co-pyrolysis of sawdust and coal blend based on volatile matters are higher than those of the sum of sawdust and coal individually. Form TGA experiments, weight loss rate of sawdust and coal blend increases above 400 degrees C and additional weight loss was observed at 700 degrees C. In a fixed bed at isothermal condition, the synergy to produce more volatiles is appeared at 500-700 degrees C, and the maximum synergy exhibits with a sawdust blending ratio of 0.6 at 600 degrees C. The gas product yields remarkably increase at lower temperature range by reducing tar yield. The CO yield increases up to 26% at 400 degrees C and CH(4) yield increases up to 62% at 600 degrees C compared with the calculated value from the additive model. (c) 2010 Elsevier Ltd. All rights reserved.

Mass-transfer limitations for immobilized enzyme-catalyzed kinetic resolution of racemate in a fixed-bed reactor.

PubMed

Xiu, G H; Jiang, L; Li, P

2001-07-05

A mathematical model has been developed for immobilized enzyme-catalyzed kinetic resolution of racemate in a fixed-bed reactor in which the enzyme-catalyzed reaction (the irreversible uni-uni competitive Michaelis-Menten kinetics is chosen as an example) was coupled with intraparticle diffusion, external mass transfer, and axial dispersion. The effects of mass-transfer limitations, competitive inhibition of substrates, deactivation on the enzyme effective enantioselectivity, and the optical purity and yield of the desired product are examined quantitatively over a wide range of parameters using the orthogonal collocation method. For a first-order reaction, an analytical solution is derived from the mathematical model for slab-, cylindrical-, and spherical-enzyme supports. Based on the analytical solution for the steady-state resolution process, a new concise formulation is presented to predict quantitatively the mass-transfer limitations on enzyme effective enantioselectivity and optical purity and yield of the desired product for a continuous steady-state kinetic resolution process in a fixed-bed reactor. Copyright 2001 John Wiley & Sons, Inc.

Stay Legal and Safe in Treating for Bed Bugs

EPA Pesticide Factsheets

Quick fix solutions may sound appealing, but they may not be legal, safe, or effective. To avoid adverse effects such as poisoning, buy EPA-registered pesticides labeled for bed bug control, and follow all label directions and precautions.

Moisture and drug solid-state monitoring during a continuous drying process using empirical and mass balance models.

PubMed

Fonteyne, Margot; Gildemyn, Delphine; Peeters, Elisabeth; Mortier, Séverine Thérèse F C; Vercruysse, Jurgen; Gernaey, Krist V; Vervaet, Chris; Remon, Jean Paul; Nopens, Ingmar; De Beer, Thomas

2014-08-01

Classically, the end point detection during fluid bed drying has been performed using indirect parameters, such as the product temperature or the humidity of the outlet drying air. This paper aims at comparing those classic methods to both in-line moisture and solid-state determination by means of Process Analytical Technology (PAT) tools (Raman and NIR spectroscopy) and a mass balance approach. The six-segmented fluid bed drying system being part of a fully continuous from-powder-to-tablet production line (ConsiGma™-25) was used for this study. A theophylline:lactose:PVP (30:67.5:2.5) blend was chosen as model formulation. For the development of the NIR-based moisture determination model, 15 calibration experiments in the fluid bed dryer were performed. Six test experiments were conducted afterwards, and the product was monitored in-line with NIR and Raman spectroscopy during drying. The results (drying endpoint and residual moisture) obtained via the NIR-based moisture determination model, the classical approach by means of indirect parameters and the mass balance model were then compared. Our conclusion is that the PAT-based method is most suited for use in a production set-up. Secondly, the different size fractions of the dried granules obtained during different experiments (fines, yield and oversized granules) were compared separately, revealing differences in both solid state of theophylline and moisture content between the different granule size fractions. Copyright © 2014 Elsevier B.V. All rights reserved.

Hydrodynamics and morphodynamics of a mobile bed confluence under equilibrium conditions for different values of the flow discharge ratio

NASA Astrophysics Data System (ADS)

Birjukova Canelas, Olga; Lage Ferreira, Rui Miguel; Heleno Cardoso, António

2017-04-01

Under steady water and sediment feeding in laboratory conditions, sediment fluxes tend to reach a steady state and bed morphology tends to equilibrium. This laboratory study states two objectives: i) to provide a detailed three-dimensional characterization of the flow field at a movable bed confluence and ii) to contribute to the characterization of the effect of the flow discharge ratio (Qr = Qt/Qm, Qt - tributary flow discharge and Qm - main channel flow discharge) on the flow field. While the junction angle between the main channel and the tributary as well as the sediment discharge ratio were kept constant, two scenarios corresponding to two different flow discharge ratios with dominant main channel flow discharge (Qm > Qt) were analyzed. Prior to the flow velocity measurements, both channels were fed with water and sand mixtures and tests were run until the equilibrium condition was reached, i.e. until the moment where the difference between the total supplied sand discharge and the total outgoing sand discharge was smaller than ± 5%. During the experiments, bed topography was systematically recorded. Then, the flow was stopped, the water was slowly drained and the bed was carefully fixed with a cement and vernix coat and allowed to dry to guarantee that it remained stable from there on, while the clear water (free of sand) discharges were fed again to the fixed bed converging channels. A 3D side looking Acoustic Doppler Velocimeter (ADV), installed on a remotely controlled and precisely positioned (± 0.1 mm) robotic arm, was used to measure the instantaneous velocities at a very dense mesh. Once the velocities measured and recorded, the water surface levels were surveyed. For the case with more dominant tributary flow (Qr = 0.17), as expected, the scour hole formed at the tributary mouth is much deeper and larger and extends towards the outer bank of the post-confluence channel, as well as upstream the junction corner. The avalanche slopes are, consequently, steeper. On the other hand, for the case with a weaker tributary flow (Qr = 0.08), no erosion is observed immediately upstream the junction. Moreover, the bank-attached sediment bar downstream the junction is considerably more developed in longitudinal and vertical directions. In both scenarios, a strong horizontal vortical structure was observed immediately downstream the junction. More detailed analysis of the origin and the characteristics of these and other flow patterns is still under investigation. Acknowledgements This research as partially supported by Portuguese and European funds, within programs COMPETE2020 and PORL-FEDER, through project PTDC/ECM-HID/6387/2014 granted by the National Foundation for Science and Technology (FCT).

Inclined fluidized bed system for drying fine coal

DOEpatents

Cha, Chang Y.; Merriam, Norman W.; Boysen, John E.

1992-02-11

Coal is processed in an inclined fluidized bed dryer operated in a plug-flow manner with zonal temperature and composition control, and an inert fluidizing gas, such as carbon dioxide or combustion gas. Recycled carbon dioxide, which is used for drying, pyrolysis, quenching, and cooling, is produced by partial decarboxylation of the coal. The coal is heated sufficiently to mobilize coal tar by further pyrolysis, which seals micropores upon quenching. Further cooling with carbon dioxide enhances stabilization.

Attrition Resistant Iron-Based Catalysts For F-T SBCRs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeyinka A. Adeyiga

2006-01-31

The Fischer-Tropsch (F-T) reaction provides a way of converting coal-derived synthesis gas (CO+ H{sub 2}) to liquid fuels. Since the reaction is highly exothermic, one of the major problems in control of the reaction is heat removal. Recent work has shown that the use of slurry bubble column reactors (SBCRs) can largely solve this problem. The use of iron-(FE) based catalysts is attractive not only due to their low cost and ready availability, but also due to their high water-gas shift activity which makes it possible to use these catalysts with low H{sub 2}/CO ratios. However, a serious problem withmore » the use of Fe catalysts in a SBCR is their tendency to undergo attrition. This can cause fouling/plugging of downstream filters and equipment; makes the separation of catalyst from the oil/wax product very difficult, if not impossible; and results in a steady loss of catalyst from the reactor. Under a previous Department of Energy (DOE)/University Research Grant (UCR) grant, Hampton University reported, for the first time, the development of demonstrably attrition-resistant Fe F-T synthesis catalysts having good activity, selectivity, and attrition resistance. These catalysts were prepared by spray drying Fe catalysts with potassium (K), copper (Cu), and silica (SiO{sub 2}) as promoters. SiO{sub 2} was also used as a binder for spray drying. These catalysts were tested for activity and selectivity in a laboratory-scale fixed-bed reactor. Fundamental understanding of attrition is being addressed by incorporating suitable binders into the catalyst recipe. This has resulted in the preparation of a spray dried HPR-43 catalyst having average particle size (aps) of 70 {micro}m with high attrition resistance. This HPR-43 attrition resistant, active and selective catalyst gave 95% CO conversion through 125 hours of testing in a fixed-bed at 270 C, 1.48 MPa, H{sub 2}/CO=0.67 and 2.0 NL/g-cat/h with C{sub 5+} selectivity of >78% and methane selectivity of less than 5% at an {alpha} of 0.9. Research is proposed to enable further development and optimization of these catalysts by (1) better understanding the role and interrelationship of various catalyst composition and preparation parameters on attrition resistance, activity, and selectivity of these catalysts, (2) the presence of sulfide ions on a precipitated iron catalyst, and (3) the effect of water on sulfided iron F-T catalysts for its activity, selectivity, and attrition. Catalyst preparations will be based on spray drying. The research employed, among other measurements, attrition testing and F-T synthesis at high pressure. Catalyst activity and selectivity is evaluated using a small fixed-bed reactor and a continuous stirred tank reactor (CSTR). The catalysts were prepared by co-precipitation, followed by binder addition and spray drying at 250 C in a 1-m-diameter, 2-m-tall spray dryer. The binder silica content was varied from 0 to 20 wt%. The results show that the use of small amounts of precipitated SiO{sub 2} alone in spray-dried Fe catalysts can result in good attrition resistance. All catalysts investigated with SiO2 wt% {le} 12 produced fines less than 10 wt% during the jet cup attrition test, making them suitable for long-term use in a slurry bubble column reactor. Thus, concentration rather than the type of SiO{sub 2} incorporated into catalyst has a more critical impact on catalyst attrition resistance of spray-dried Fe catalysts. Lower amounts of SiO{sub 2} added to a catalyst give higher particle densities and therefore higher attrition resistances. In order to produce a suitable SBCR catalyst, however, the amount of SiO{sub 2} added has to be optimized to provide adequate surface area, particle density, and attrition resistance. Two of the catalysts with precipitated and binder silica were tested in Texas A&M University's CSTR (Autoclave Engineers). The two catalysts were also tested at The Center for Applied Energy Research in Lexington, Kentucky of the University of Kentucky. Spray-dried catalysts with compositions 100 Fe/5 Cu/4.2 K/11 (P) SiO{sub 2} and 100 Fe/5 Cu/4.2 K/1.1 (B) SiO{sub 2} have excellent selectivity characteristics (low methane and high C{sub 5+} yields), but their productivity and stability (deactivation rate) need to be improved. Mechanical integrity (attrition strength) of these two catalysts was markedly dependent upon their morphological features. The attrition strength of the catalyst made out of largely spherical particles (1.1 (B) SiO{sub 2}) was considerably higher than that of the catalyst consisting of irregularly shaped particles (11 (P) SiO{sub 2}).« less

Pilot scale-SO{sub 2} control by dry sodium bicarbonate injection and an electrostatic precipitator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pliat, M.J.; Wilder, J.M.

2007-10-15

A 500 actual cubic feet gas per minute (acfm) pilot-scale SO{sub 2} control study was undertaken to investigate flue gas desulfurization (FGD) by dry sodium sorbents in 400{sup o}F (204.5{sup o}C) flue gases emitted from a coal fired boiler with flue gas concentrations between 350 and 2500 ppm SO{sub 2}. Powdered sodium alkaline reagents were injected into the hot flue gas downstream of the air preheater and the spent reagents were collected using an electrostatic precipitator. Three different sorbents were used: processed sodium bicarbonate of two particle sizes; solution mined sodium bicarbonate, and processed sodium sesquicarbonate. SO{sub 2} concentrations weremore » measured upstream of the reagent injection, 25-ft (7.62 m) downstream of the injection point, and downstream of the electrostatic precipitator. SO{sub 2} collection efficiencies ranged from 40 to 80% using sodium bicarbonate stoichiometric ratios from 0.5 to 3.0. Much of the in-duct SO{sub 2} removal occurred during the first second of reagent reaction time, indicating that the sulfur dioxide-sodium reaction rates may be faster than have been measured for fixed bed measurements reported in the literature.« less

Robust Immobilized Amine CO 2 Sorbent Pellets Utilizing a Poly(Chloroprene) Polymer Binder and Fly Ash Additive

DOE PAGES

Wilfong, Walter Christopher; Kail, Brian W.; Howard, Bret H.; ...

2016-08-04

Pelletization of ca. 50 wt % amine/silica carbon dioxide sorbents was achieved with the novel combination of fly ash (FA) as a strength additive and hydrophobic poly(chloroprene) (PC) as a binder. The PC content and overall synthesis procedure of these materials were optimized to produce pellets, labeled as FA/E100-S_(20/80)_12.2, with the highest ball-mill attrition resistance (<0.5 wt % by fines, 24 h) and maximum CO 2 capture capacity of 1.78 mmol CO 2 g -1. The strength of the pellets was attributed to hydrogen-bonding of the relatively homogeneous PC network with the interlocked FA and BIAS particles (DRIFTS, SEM-EDS). Themore » low degradation of 3–4 % in the pellet's CO 2 capture capacity under both dry TGA (7.5 h) and practical fixed-bed (6.5 h dry; 4.5 h humid,≈5 vol % H 2O) CO 2 adsorption–desorption conditions highlights the pellet's excellent cyclic stability. These robust pellet characteristics make PC/FA/sorbent materials promising for commercial scale, point-source CO 2 capture.« less

Boron removal by a composite sorbent: Polyethylenimine/tannic acid derivative immobilized in alginate hydrogel beads.

PubMed

Bertagnolli, Caroline; Grishin, Andrey; Vincent, Thierry; Guibal, Eric

2017-03-21

A novel composite material was prepared by the grafting of tannic acid on polyethylenimine (PEI), which allows an efficient sorption of boron (sorption capacity close to 0.89 mmol B g -1 ). The encapsulation of this chelating sorbent (finely crushed) facilitates its use (readily solid/liquid separation, use in fixed-bed columns) at the expense of a loss in sorption capacity (proportionally decreased by the introduction of alginate having poor efficiency for boron uptake). Sorption isotherms are modeled using the Langmuir equation, while the kinetic profiles are presented a good fit by pseudo-second order rate equation. In addition, the encapsulating matrix introduces supplementary resistance to intraparticle diffusion, especially when the resin is dried without control: freeze-drying partially limits this effect. The stability (at long-term storage) of the sorbent is improved when the sorbent is stored under nitrogen atmosphere. The presence of an excess of NaCl was investigated. The degradation of the hydrogel (by ion-exchange of Ca(II) with Na(I)) leads to a decrease in the sorption performance of composite material but the action of Ca(II) ions in the solutions re-stabilizes the hydrogel.

DESIGNING FIXED-BED ADSORBERS TO REMOVE MIXTURES OF ORGANICS.

EPA Science Inventory

A liquid-phase granular activated carbon (GAC) pilot plant and a full-scale GAC adsorber were designed, built, and operated in order to evaluate their performance for treating a groundwater contaminated with several volatile and synthetic organic chemicals. Several empty bed con...

Riverside East Solar Energy Zone (SEZ) - California

Science.gov Websites

Los Mogotes East Nevada Amargosa Valley Dry Lake Dry Lake Valley North Gold Point Millers New Mexico Pavement Cultural Gravel Bench I 10 Wiley Well Road South Wiley Well Rest Stop Ford Dry Lake Get Adobe there are also dry lake beds, sandy areas, and dry washes with ironwood and other trees. Some areas are

Advanced development of immobilized enzyme reactors

NASA Technical Reports Server (NTRS)

Jolly, Clifford D.; Schussel, Leonard J.; Carter, Layne

1991-01-01

Fixed-bed reactors have been used at NASA-Marshall to purify wastewater generated by an end-use equipment facility, on the basis of a combination of multifiltration unibeds and enzyme unibeds. The enzyme beds were found to effectively remove such targeted organics as urea, alcohols, and aldehydes, down to levels lying below detection limits. The enzyme beds were also found to remove organic contaminants not specifically targeted.

Mineral Separation in a CELSS by Ion-exchange Chromatography

NASA Technical Reports Server (NTRS)

Ballou, E. V.; Spitze, L. A.; Wong, F. W.; Wydeven, T.; Johnson, C. C.

1982-01-01

Operational parameters pertinent to ion exchange chromatography separation were identified. The experiments were performed with 9 mm diameter ion exchange columns and conventional column accessories. The cation separation beds were packed with AG 50W-X2 strong acid cation exchange resin in H(+) form and 200-400 dry mesh particle size. The stripper beds used in some experiments were packed with AG 1-XB strong base cation exchange resin in OH(-) form and 200-400 dry mesh particle size.

Drought Stress Response of Dry Forest Trees of the Brazilian Caatinga

NASA Astrophysics Data System (ADS)

Menezes, R.; Worbes, M.

2015-12-01

Martin Worbes and Romulo Menezes In the frame of the "Tropi-Dry" network we studied drought response strategies of six tree species in a Caatinga forest at the Fazenda Tamandua near Patos in Paraiba, NE Brazil. We selected the tree species as representatives of the different phenological ecotypes: evergreen, deciduous and stem succulent. The deciduous group comprised N-fixing as well as non N-fixing Leguminosae. Over an entire vegetation period (dry and wet-season) we monitored their phenological behaviour, photosynthesis rates, stomata conductance and water potential, measured if leaves were present and we estimated seasonal variations in stable carbon and N15 content of the leaves. The major results are: Evergreen species (e.g. Capparis) may compensate low carbon-fixing rates in the wet season with a much longer vegetation period as the deciduous species. Stem succulents (Jatropha) do not fulfill the expectations of being high productive species under drought stress conditions, while the N-fixing Mimosa performed in particular at the end and the beginning of the dry period better than the rest of the investigated species. In general the results may help to understand different strategies of tree species in respect to extended dry periods of at least six months as in our study area and their role in carbon sequestration of tropical dry forests. The variety of observed strategies may contribute to the resilience of the ecosystem tropical dry forests.

Fixed-bed operation for manganese removal from water using chitosan/bentonite/MnO composite beads.

PubMed

Muliwa, Anthony M; Leswifi, Taile Y; Maity, Arjun; Ochieng, Aoyi; Onyango, Maurice S

2018-04-24

In the present study, a new composite adsorbent, chitosan/bentonite/manganese oxide (CBMnO) beads, cross-linked with tetraethyl-ortho-silicate (TEOS) was applied in a fixed-bed column for the removal of Mn (II) from water. The adsorbent was characterised by scanning electron microscopy (SEM), Fourier transform infra-red (FT-IR), N 2 adsorption-desorption and X-ray photoelectron spectroscopy (XPS) techniques, and moreover the point of zero charge (pH pzc ) was determined. The extend of Mn (II) breakthrough behaviour was investigated by varying bed mass, flow rate and influent concentration, and by using real environmental water samples. The dynamics of the column showed great dependency of breakthrough curves on the process conditions. The breakthrough time (t b ), bed exhaustion time (t s ), bed capacity (q e ) and the overall bed efficiency (R%) increased with an increase in bed mass, but decreased with the increase in both influent flow rate and concentration. Non-linear regression suggested that the Thomas model effectively described the breakthrough curves while large-scale column performance could be estimated by the bed depth service time (BDST) model. Experiments with environmental water revealed that coexisting ions had little impact on Mn (II) removal, and it was possible to achieve 6.0 mg/g breakthrough capacity (q b ), 4.0 L total treated water and 651 bed volumes processed with an initial concentration of 38.5 mg/L and 5.0 g bed mass. The exhausted bed could be regenerated with 0.001 M nitric acid solution within 1 h, and the sorbent could be reused twice without any significant loss of capacity. The findings advocate that CBMnO composite beads can provide an efficient scavenging pathway for Mn (II) in polluted water.

25. Typical valves used to control flow into and out ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

25. Typical valves used to control flow into and out of filtration bed. Left valve (painted red) drains the bed, and center valve (painted green) admits water into the bed. The right valve is a cross over valve which is used to admit water into a dry bed from the bottom. This bottom fill excludes entrapped air as the bed is filled. When the water reached to top of the bed, filling is continued from the top of the bed. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

Fixed bed column study for water defluoridation using neem oil-phenolic resin treated plant bio-sorbent.

PubMed

Manna, Suvendu; Saha, Prosenjit; Roy, Debasis; Adhikari, Basudam; Das, Papita

2018-04-15

Fluoride has both detrimental and beneficial effects on living beings depending on the concentration and consumption periods. The study presented in this article investigated the feasibility of using neem oil phenolic resin treated lignocellulosic bio-sorbents for fluoride removal from water through fixed bed column study. Results indicated that treated bio-sorbents could remove fluoride both from synthetic and groundwater with variable bed depth, flow rate, fluoride concentration and column diameter. Data obtained from this study indicated that columns with the thickest bed, lowest flow rate, and fluoride concentration showed best column performance. Bio-sorbents used in this study are regenerable and reusable for more than five cycles. The initial materials cost needed to remove one gram of fluoride also found to be lower than the available alternatives. This makes the process more promising candidate to be used for fluoride removal. In addition, the process is also technically advantageous over the available alternatives. Copyright © 2018 Elsevier Ltd. All rights reserved.

Research on acting mechanism and behavior of a gas bubble in the air dense medium fluidized bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tao, X.; Chen, Q.; Yang, Y.

1996-12-31

Coal dry beneficiation with air-dense medium fluidized bed has now been established as a high efficiency dry separation technology, it is the application of fluidization technology to the coal preparation field. The tiny particle media forms an uniform and stable fluidized bed with a density acted by airflow, which is used to separate 80{micro}m to {approximately}6mm size coal. This technology has achieved satisfied industrialization results, and attracted the expert`s attention in the field. In fluidized bed, the interaction between gas and solid was mainly decided by the existence state of heavy media particles mass (position and distance) relative velocity ofmore » gas-solid two phase, as well turbulent action. A change of vertical gas-solid fluidizing state essentially is the one of a energy transforming process. For a coal separating process with air-dense medium fluidized bed, the gas bubble, producing a turbulent and stirring action in the bed, leads to two effects. It can promote a uniform distribution of heavy media particles, and a uniform and stability of a bed density. Otherwise it will decrease effective contacts between gas-solids two phases, producing a bigger gas bubble. Therefore controlling a gas bubble size in bed should be optimized. This paper analyzes mutual movement between gas-solid, and studies the gas bubble behavior in the bed. A mechanic mode and a separating process of coal in the bed is discussed. It aims to research the coal separating mechanism with air-dense fluidized bed.« less

An evaluation of tannery industry wastewater treatment sludge gasification by artificial neural network modeling.

PubMed

Ongen, Atakan; Ozcan, H Kurtulus; Arayıcı, Semiha

2013-12-15

This paper reports on the calorific value of synthetic gas (syngas) produced by gasification of dewatered sludge derived from treatment of tannery wastewater. Proximate and ultimate analyses of samples were performed. Thermochemical conversion alters the chemical structure of the waste. Dried air was used as a gasification agent at varying flow rates, which allowed the feedstock to be quickly converted into gas by means of different heterogeneous reactions. A lab-scale updraft fixed-bed steel reactor was used for thermochemical conversion of sludge samples. Artificial neural network (ANN) modeling techniques were used to observe variations in the syngas related to operational conditions. Modeled outputs showed that temporal changes of model predictions were in close accordance with real values. Correlation coefficients (r) showed that the ANN used in this study gave results with high sensitivity. Copyright © 2013 Elsevier B.V. All rights reserved.

Remediation of trichloroethylene by bio-precipitated and encapsulated palladium nanoparticles in a fixed bed reactor.

PubMed

Hennebel, Tom; Verhagen, Pieter; Simoen, Henri; De Gusseme, Bart; Vlaeminck, Siegfried E; Boon, Nico; Verstraete, Willy

2009-08-01

Trichloroethylene is a toxic and recalcitrant groundwater pollutant. Palladium nanoparticles bio-precipitated on Shewanella oneidensis were encapsulated in polyurethane, polyacrylamide, alginate, silica or coated on zeolites. The reactivity of these bio-Pd beads and zeolites was tested in batch experiments and trichloroethylene dechlorination followed first order reaction kinetics. The calculated k-values of the encapsulated catalysts were a factor of six lower compared to non-encapsulated bio-Pd. Bio-Pd, used as a catalyst, was able to dechlorinate 100 mgL(-1) trichloroethylene within a time period of 1h. The main reaction product was ethane; yet small levels of chlorinated intermediates were detected. Subsequently polyurethane cubes empowered with bio-Pd were implemented in a fixed bed reactor for the treatment of water containing trichloroethylene. The influent recycle configuration resulted in a cumulative removal of 98% after 22 h. The same reactor in a flow through configuration achieved removal rates up to 1059 mg trichloroethylene g Pd(-1)d(-1). This work showed that fixed bed reactors with bio-Pd polyurethane cubes can be instrumental for remediation of water contaminated with trichloroethylene.

Co-pyrolysis behaviors of saw dust and Shenfu coal in drop tube furnace and fixed bed reactor.

PubMed

Li, Shuaidan; Chen, Xueli; Wang, Li; Liu, Aibin; Yu, Guangsuo

2013-11-01

Co-pyrolysis behaviors of saw dust (SD) and Shenfu bituminous coal (SF) were studied in a drop tube furnace and a fixed bed reactor at different temperatures respectively. Six different biomass/coal ratios (B:C) were used. Compared the results with the calculated value obtained by the additional behavior, CO volume yields were lower while H2, CH4, CO2, volume yields were higher. Blend char yields had a good agreement with the calculated values, and their structures remained similar with SD and SF char's. Synergy effect occurred in gaseous phase, which was mainly caused by the secondary reactions. Compared the blend char yields in the drop tube furnace with those in the fixed bed reactor, the results showed the contacting way of biomass and coal particles had little influence on char yield in co-pyrolysis process. The reactivity index of blend char achieved the minimum at B:C=40:60 and the maximum at B:C=80:20. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dry particle generation with a 3-D printed fluidized bed generator

DOE PAGES

Roesch, Michael; Roesch, Carolin; Cziczo, Daniel J.

2017-06-02

We describe the design and testing of PRIZE (PRinted fluidIZed bed gEnerator), a compact fluidized bed aerosol generator manufactured using stereolithography (SLA) printing. Dispersing small quantities of powdered materials – due to either rarity or expense – is challenging due to a lack of small, low-cost dry aerosol generators. With this as motivation, we designed and built a generator that uses a mineral dust or other dry powder sample mixed with bronze beads that sit atop a porous screen. A particle-free airflow is introduced, dispersing the sample as airborne particles. The total particle number concentrations and size distributions were measured duringmore » different stages of the assembling process to show that the SLA 3-D printed generator did not generate particles until the mineral dust sample was introduced. Furthermore, time-series measurements with Arizona Test Dust (ATD) showed stable total particle number concentrations of 10–150 cm -3, depending on the sample mass, from the sub- to super-micrometer size range. Additional tests with collected soil dust samples are also presented. PRIZE is simple to assemble, easy to clean, inexpensive and deployable for laboratory and field studies that require dry particle generation.« less

Dry particle generation with a 3-D printed fluidized bed generator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roesch, Michael; Roesch, Carolin; Cziczo, Daniel J.

We describe the design and testing of PRIZE (PRinted fluidIZed bed gEnerator), a compact fluidized bed aerosol generator manufactured using stereolithography (SLA) printing. Dispersing small quantities of powdered materials – due to either rarity or expense – is challenging due to a lack of small, low-cost dry aerosol generators. With this as motivation, we designed and built a generator that uses a mineral dust or other dry powder sample mixed with bronze beads that sit atop a porous screen. A particle-free airflow is introduced, dispersing the sample as airborne particles. The total particle number concentrations and size distributions were measured duringmore » different stages of the assembling process to show that the SLA 3-D printed generator did not generate particles until the mineral dust sample was introduced. Furthermore, time-series measurements with Arizona Test Dust (ATD) showed stable total particle number concentrations of 10–150 cm -3, depending on the sample mass, from the sub- to super-micrometer size range. Additional tests with collected soil dust samples are also presented. PRIZE is simple to assemble, easy to clean, inexpensive and deployable for laboratory and field studies that require dry particle generation.« less

Development and evaluation of a dimensionless mechanistic pan coating model for the prediction of coated tablet appearance.

PubMed

Niblett, Daniel; Porter, Stuart; Reynolds, Gavin; Morgan, Tomos; Greenamoyer, Jennifer; Hach, Ronald; Sido, Stephanie; Karan, Kapish; Gabbott, Ian

2017-08-07

A mathematical, mechanistic tablet film-coating model has been developed for pharmaceutical pan coating systems based on the mechanisms of atomisation, tablet bed movement and droplet drying with the main purpose of predicting tablet appearance quality. Two dimensionless quantities were used to characterise the product properties and operating parameters: the dimensionless Spray Flux (relating to area coverage of the spray droplets) and the Niblett Number (relating to the time available for drying of coating droplets). The Niblett Number is the ratio between the time a droplet needs to dry under given thermodynamic conditions and the time available for the droplet while on the surface of the tablet bed. The time available for drying on the tablet bed surface is critical for appearance quality. These two dimensionless quantities were used to select process parameters for a set of 22 coating experiments, performed over a wide range of multivariate process parameters. The dimensionless Regime Map created can be used to visualise the effect of interacting process parameters on overall tablet appearance quality and defects such as picking and logo bridging. Copyright © 2017 Elsevier B.V. All rights reserved.

Fixed-bed column performances of azure-II and auramine-O adsorption by Pinus eldarica stalks activated carbon and its composite with zno nanoparticles: Optimization by response surface methodology based on central composite design.

PubMed

Jafari, Maryam; Rahimi, Mahmood Reza; Ghaedi, Mehrorang; Javadian, Hamedreza; Asfaram, Arash

2017-12-01

A continuous adsorption was used for removal of azure II (AZ II) and auramine O (AO) from aqueous solutions using Pinus eldarica stalks activated carbon (PES-AC) from aqueous solutions. The effects of initial dye concentration, flow rate, bed height and contact time on removal percentage of AO and AZ II were evaluated and optimized by central composite design (CCD) at optimum pH = 7.0. ZnO nanoparticles loaded on activated carbon were also used to remove AO and AZ II at pH = 7.0 and other optimum conditions. The breakthrough curves were obtained at different flow rates, initial dye concentrations and bed heights and the experimental data were fitted by Thomas, Adams-Bohart and Yoon-Nelson models. The main parameters of fixed-bed column including its adsorption capacity at breakthrough point (q b ), adsorption capacity at saturation point (q s ), mass transfer zone (MTZ), total removal percentage (R%), and empty bed contact time (EBCT) were calculated. The removal percentages calculated for AZ II and AO II were in the range of 51.6-61.1% and 40.6-61.6%, respectively. Bed adsorption capacity (N 0 ) and critical bed depth (Z 0 ) were obtained by BDST model. Copyright © 2017 Elsevier Inc. All rights reserved.

Virtual Design of a Four-Bed Molecular Sieve for Exploration

NASA Technical Reports Server (NTRS)

Giesy, T. J.; Coker, R. F.; O'Connor, B. F.; Knox, J. C.

2017-01-01

Aboard the International Space Station, CO2 is removed from the cabin atmosphere by a four-bed molecular sieve (4BMS) process called the Carbon Dioxide Removal Assembly (CDRA).1 This 4BMS process operates by passing the CO2-laden air through a desiccant bed to remove any humidity and then passing the dried air through a sorbent bed to remove the CO2. While one pair of beds is in use, the other pair is thermally regenerated to allow for continuous CO2 removal.

Recent developments in drying of food products

NASA Astrophysics Data System (ADS)

Valarmathi, T. N.; Sekar, S.; Purushothaman, M.; Sekar, S. D.; Rama Sharath Reddy, Maddela; Reddy, Kancham Reddy Naveen Kumar

2017-05-01

Drying is a dehydration process to preserve agricultural products for long period usage. The most common and cheapest method is open sun drying in which the products are simply laid on ground, road, mats, roof, etc. But the open sun drying has some disadvantages like dependent on good weather, contamination by dust, birds and animals consume a considerable quantity, slow drying rate and damages due to strong winds and rain. To overcome these difficulties solar dryers are developed with closed environment for drying agricultural products effectively. To obtain good quality food with reduced energy consumption, selection of appropriate drying process and proper input parameters is essential. In recent years several researchers across the world have developed new drying systems for improving the product quality, increasing the drying rate, decreasing the energy consumption, etc. Some of the new systems are fluidized bed, vibrated fluidized bed, desiccant, microwave, vacuum, freeze, infrared, intermittent, electro hydrodynamic and hybrid dryers. In this review the most recent progress in the field of drying of agricultural food products such as new methods, new products and modeling and optimization techniques has been presented. Challenges and future directions are also highlighted. The review will be useful for new researchers entering into this ever needed and ever growing field of engineering.

Two-stage fixed-bed gasifier with selectable middle gas off-take point

DOEpatents

Strickland, Larry D.; Bissett, Larry A.

1992-01-01

A two-stage fixed bed coal gasifier wherein an annular region is in registry with a gasification zone underlying a devolatilization zone for extracting a side stream of high temperature substantially tar-free gas from the gasifier. A vertically displaceable skirt means is positioned within the gasifier to define the lower portion of the annular region so that vertical displacement of the skirt means positions the inlet into the annular region in a selected location within or in close proximity to the gasification zone for providing a positive control over the composition of the side stream gas.

Removal of dioxins and furans from flue gases by non-flammable adsorbents in a fixed bed.

PubMed

Fell, H J; Tuczek, M

1998-01-01

The presented adsorption--process KOMBISORBON is applied for high efficient off-gas purification, preferably of polychlorinated dioxins and furans from off-gas of incineration plants, which are generated, when these are operated under unfavourable conditions [2]. This off-gas purification process complies with german laws, which limit the concentration of these substances to less than 0.1 ng toxicity equivalents (TE) per cubic metre of gas [1]. The adsorbent, the adsorption process and its plant concept (fixed bed) is described in detail including economics and obtained operation results. Alternative removal technologies are briefly outlined.

Modeling adsorption of copper(II), cobalt(II) and nickel(II) metal ions from aqueous solution onto a new carboxylated sugarcane bagasse. Part II: Optimization of monocomponent fixed-bed column adsorption.

PubMed

Xavier, Amália Luísa Pedrosa; Adarme, Oscar Fernando Herrera; Furtado, Laís Milagres; Ferreira, Gabriel Max Dias; da Silva, Luis Henrique Mendes; Gil, Laurent Frédéric; Gurgel, Leandro Vinícius Alves

2018-04-15

In the second part of this series of studies, the monocomponent adsorption of Cu 2+ , Co 2+ and Ni 2+ onto STA adsorbent in a fixed-bed column was investigated and optimized using a 2 2 central composite design. The process variables studied were: initial metal ion concentration and spatial time, and the optimized responses were: adsorption capacity of the bed (Q max ), efficiency of the adsorption process (EAP), and effective use of the bed (H). The higher Q max for Cu 2+ , Co 2+ and Ni 2+ were 1.060, 0.800 and 1.029 mmol/g, respectively. The breakthrough curves were modeled by the original Thomas and Bohart-Adams models. The changes in enthalpy (Δ ads H°) of adsorption of the metal ions onto STA were determined by isothermal titration calorimetry (ITC). The values of Δ ads H° were in the range of 3.0-6.8 kJ/mol, suggesting that the adsorption process involved physisorption. Desorption (E des ) and re-adsorption (E re-ads ) of metal ions from the STA adsorbent were also investigated in batch mode, and the optimum conditions were applied for three cycles of adsorption/desorption in a fixed bed column. For these cycles, the lowest values of E des and E re-ads were 95 and 92.3%, respectively, showing that STA is a promising candidate for real applications on a large scale. Copyright © 2018 Elsevier Inc. All rights reserved.

Development of a Rational Modeling Approach for the Design, and Optimization of the Multifiltration Unit. Volume 1

NASA Technical Reports Server (NTRS)

Hand, David W.; Crittenden, John C.; Ali, Anisa N.; Bulloch, John L.; Hokanson, David R.; Parrem, David L.

1996-01-01

This thesis includes the development and verification of an adsorption model for analysis and optimization of the adsorption processes within the International Space Station multifiltration beds. The fixed bed adsorption model includes multicomponent equilibrium and both external and intraparticle mass transfer resistances. Single solute isotherm parameters were used in the multicomponent equilibrium description to predict the competitive adsorption interactions occurring during the adsorption process. The multicomponent equilibrium description used the Fictive Component Analysis to describe adsorption in unknown background matrices. Multicomponent isotherms were used to validate the multicomponent equilibrium description. Column studies were used to develop and validate external and intraparticle mass transfer parameter correlations for compounds of interest. The fixed bed model was verified using a shower and handwash ersatz water which served as a surrogate to the actual shower and handwash wastewater.

Aqueous phase adsorption of cephalexin by walnut shell-based activated carbon: A fixed-bed column study

NASA Astrophysics Data System (ADS)

Nazari, Ghadir; Abolghasemi, Hossein; Esmaieli, Mohamad; Sadeghi Pouya, Ehsan

2016-07-01

The walnut shell was used as a low cost adsorbent to produce activated carbon (AC) for the removal of cephalexin (CFX) from aqueous solution. A fixed-bed column adsorption was carried out using the walnut shell AC. The effect of various parameters like bed height (1.5, 2 and 2.5 cm), flow rate (4.5, 6 and 7.5 mL/min) and initial CFX concentration (50, 100 and 150 mg/L) on the breakthrough characteristics of the adsorption system was investigated at optimum pH 6.5. The highest bed capacity of 211.78 mg/g was obtained using 100 mg/L inlet drug concentration, 2 cm bed height and 4.5 mL/min flow rate. Three kinetic models, namely Adam's-Bohart, Thomas and Yoon-Nelson were applied for analysis of experimental data. The Thomas and Yoon-Nelson models were appropriate for walnut shell AC column design under various conditions. The experimental adsorption capacity values were fitted to the Bangham and intra-particle diffusion models in order to propose adsorption mechanisms. The effect of temperature on the degradation of CFX was also studied.

Observations of axisymmetric tracer particle orientation during flow through a dilute fixed bed of fibers

NASA Astrophysics Data System (ADS)

Frattini, Paul L.; Shaqfeh, Eric S. G.; Levy, Jeffrey L.; Koch, Donald L.

1991-11-01

Direct microstructural evidence for net tracer particle orientation induced solely by hydrodynamic interactions in a dilute, disordered, fibrous media is reported. A dilute fixed bed of randomly placed fibers was constructed and glycerol/water suspensions of either synthetic akaganeite (βFeOOH, average aspect ratio 6.3) or hematite (αFe2O3, average aspect ratio 1.6) tracer particles were made to flow axially through the bed at prescribed flow rates. Conservative linear dichroism, a noninvasive light scattering technique, was employed to provide a direct measure of the orientational order parameter for the tracer particle population at the end of the bed. The effect of Brownian motion on the hydrodynamically induced order in the suspensions was studied over three orders of magnitude in scaled rotary Peclet number, 5

Biosorption of cobalt(II) with sunflower biomass from aqueous solutions in a fixed bed column and neural networks modelling.

PubMed

Oguz, Ensar; Ersoy, Muhammed

2014-01-01

The effects of inlet cobalt(II) concentration (20-60 ppm), feed flow rate (8-19 ml/min) and bed height (5-15 cm), initial solution pH (3-5) and particle size (0.25

Transient Combustion in Granular Propellant Beds. Part I. Theoretical Modeling and Numerical Solution of Transient Combustion Processes in Mobile Granular Propellant Beds

DTIC Science & Technology

1977-08-01

TR~ANSIENT COMBUSTION PROCESSES IN MOBILE GRANULAR PROPELLANT BEDS Prqprid by The Pennsylvania Stats UnIversiV 197 Dopartme of Nmchanica! EngwineerIng...the ignition and flame spreadinb prc-eases by assuming that the granular propillents are fixed in space; and 3) modeling cf mobile granular beds so...through an aggrtgate of mobile "’actin&, partic~vi. The diffevewsoa Wi derivation of conservation equa~tions betvewu our approacit md this -f a Aivorain

Hydrodynamics of concordant and discordant fixed bed open-channel confluences

NASA Astrophysics Data System (ADS)

Birjukova Canelas, Olga; Lage Ferreira, Rui Miguel; Heleno Cardoso, António

2017-04-01

The detailed characterization of the flow field in river confluences constitutes a relevant step towards the understanding of the hydro-morpho-dynamics of these key zones of the fluvial system. With a few exceptions, existing works on this topic covered concordant bed scenarios, meaning that both confluent channels had the same elevation. This laboratory study aims to contribute to a detailed three-dimensional characterization of the flow field at a fixed bed confluence, as well as to shed light on how bed elevation discordance modifies the flow patterns of the converging flows. While the junction angle and the discharge ratio were kept fixed, two scenarios were studied on the basis of detailed water level and 3D ADV measurements at the denser mesh ever. The internal flow structure of the concordant bed scenario mostly complied with the classical conceptual models. A relevant difference concerns the size of the stagnation zone, much smaller close to the bed of the discordant bed confluence. A more significant difference is a horizontal flow structure, not previously identified in the literature, characterized by strong streamwise mean vorticity and strong secondary motion. It is observed for the discordant bed case, occurring along the inner wall of the main channel and downstream the junction corner. This structure is spatially well-correlated to a pronounced imbalance of cross-stream and vertical normal Reynolds stresses. This highlights the role of Reynolds stress anisotropy (RSA) that is generated in the shear layers than accompany the entrance of the tributary flow. Since this structure is not present in the concordant case, where RSA is also evident, it is argued that convective effects should also play a role in its formation, presumably due to deflection of the flow in the main channel by the tributary. The newly identified secondary motion should, thus, be a combination of Prandtĺs second kind and Prandtĺs first kind of secondary flow. The relative importance of each generating mechanism is still under investigation. Acknowledgements This research as partially supported by Portuguese and European funds, within programs COMPETE2020 and PORL-FEDER, through project PTDC/ECM-HID/6387/2014 granted by the National Foundation for Science and Technology (FCT).

Batch and continuous (fixed-bed column) biosorption of crystal violet by Artocarpus heterophyllus (jackfruit) leaf powder.

PubMed

Saha, Papita Das; Chakraborty, Sagnik; Chowdhury, Shamik

2012-04-01

In this study, batch and fixed-bed column experiments were performed to investigate the biosorption potential of Artocarpus heterophyllus (jackfruit) leaf powder (JLP) to remove crystal violet (CV) from aqueous solutions. Batch biosorption studies were carried out as a function of solution pH, contact time, initial dye concentration and temperature. The biosorption equilibrium data showed excellent fit to the Langmuir isotherm model with maximum monolayer biosorption capacity of 43.39 mg g(-1) at pH 7.0, initial dye concentration=50 mg L(-1), temperature=293 K and contact time=120 min. According to Dubinin-Radushkevich (D-R) isotherm model, biosorption of CV by JLP was chemisorption. The biosorption kinetics followed the pseudo-second-order kinetic model. Thermodynamic analysis revealed that biosorption of CV from aqueous solution by JLP was a spontaneous and exothermic process. In order to ascertain the practical applicability of the biosorbent, fixed-bed column studies were also performed. The breakthrough time increased with increasing bed height and decreased with increasing flow rate. The Thomas model as well as the BDST model showed good agreement with the experimental results at all the process parameters studied. It can be concluded that JLP is a promising biosorbent for removal of CV from aqueous solutions. Copyright © 2011 Elsevier B.V. All rights reserved.

CHARACTERISTICS OF MERCURY DESORPTION FROM SORBENTS AT ELEVATED TEMPERATURES. (R822721C697)

EPA Science Inventory

This study investigated the dynamic desorption characteristics of mercury during the thermal treatment of mercury-loaded sorbents at elevated temperatures under fixed-bed operations. Experiments were carried out in a 25.4 mm ID quartz bed enclosed in an electric furnace. ...

CHARACTERISTICS OF MERCURY DESORPTION FROM SORBENTS AT ELEVATED TEMPERATURES. (R826694C697)

EPA Science Inventory

This study investigated the dynamic desorption characteristics of mercury during the thermal treatment of mercury-loaded sorbents at elevated temperatures under fixed-bed operations. Experiments were carried out in a 25.4 mm ID quartz bed enclosed in an electric furnace. ...

Surplus activated sludge dewatering in pilot-scale sludge drying reed beds.

PubMed

Stefanakis, A I; Akratos, C S; Melidis, P; Tsihrintzis, V A

2009-12-30

A pilot-scale experiment on dewatering of surplus activated sludge (SAS) is presented, where two pilot-scale vertical flow, sludge drying reed beds (SDRBs), planted with Phragmites australis are used. The bottom of the beds is filled with cobbles, connected to the atmosphere through perforated PVC ventilation tubes, in order to achieve oxygen diffusion through the overlying porous medium that is colonized by roots and an abundant nitrifying biomass. Two layers of gravel, of decreasing size from bottom to top, make the drainage layer where the reeds are planted. The two beds were fed according to the following cycle: one week feeding with SAS at rates one 30 kg/m(2)/year and the other 75 kg/m(2)/year, and resting for three weeks. The results show that planted SDRBs can effectively dewater SAS from domestic sewage, the produced residual sludge presents a high dry weight content, the degree of volume reduction depends upon the initial SAS concentration and can be of the order of 90%, and decomposition of organic matter and high levels of mineralization can be achieved. Furthermore, the percolating water is not septic. The fertilizer value of the treated SAS, which contains no added chemicals, is comparable to that of SAS treated by other methods.

Feasibility Study of the Geotextile Waste Filtration Unit.

DTIC Science & Technology

2000-02-10

Treatment Module 3-32 Figure 3-20. THE SCHEMATIC OF THE MOVING BED BIOFILM REACTOR ( MBBR ) 3൪ Figure 4-1. The Original Distributed Concept for WFUs...Moving Bed Biofilm Reactor ( MBBR ) process appears to be one of the most feasible processes available to meet Force Provider liquid waste stream...Moving Bed Biofilm Reactor ( MBBR ) process was then examined.31 In this system, both activated sludge and fixed-film processes occur in a bioreactor

Simulated moving bed system for CO.sub.2 separation, and method of same

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elliott, Jeannine Elizabeth; Copeland, Robert James; Lind, Jeff

A system and method for separating and/or purification of CO.sub.2 gas from a CO.sub.2 feed stream is described. The system and method include a plurality of fixed sorbent beds, adsorption zones and desorption zones, where the sorbent beds are connected via valve and lines to create a simulated moving bed system, where the sorbent beds move from one adsorption position to another adsorption position, and then into one regeneration position to another regeneration position, and optionally back to an adsorption position. The system and method operate by concentration swing adsorption/desorption and by adsorptive/desorptive displacement.

Large-scale Clinical-grade Retroviral Vector Production in a Fixed-Bed Bioreactor

PubMed Central

Wang, Xiuyan; Olszewska, Malgorzata; Qu, Jinrong; Wasielewska, Teresa; Bartido, Shirley; Hermetet, Gregory; Sadelain, Michel

2015-01-01

The successful genetic engineering of patient T cells with γ-retroviral vectors expressing chimeric antigen receptors or T-cell receptors for phase II clinical trials and beyond requires the large-scale manufacture of high-titer vector stocks. The production of retroviral vectors from stable packaging cell lines using roller bottles or 10- to 40-layer cell factories is limited by a narrow harvest window, labor intensity, open-system operations, and the requirement for significant incubator space. To circumvent these shortcomings, we optimized the production of vector stocks in a disposable fixed-bed bioreactor using good manufacturing practice–grade packaging cell lines. High-titer vector stocks were harvested over 10 days, representing a much broader harvest window than the 3-day harvest afforded by cell factories. For PG13 and 293Vec packaging cells, the average vector titer and the vector stocks’ yield in the bioreactor were higher by 3.2- to 7.3-fold, and 5.6- to 13.1-fold, respectively, than those obtained in cell factories. The vector production was 10.4 and 18.6 times more efficient than in cell factories for PG13 and 293Vec cells, respectively. Furthermore, the vectors produced from the fixed-bed bioreactors passed the release test assays for clinical applications. Therefore, a single vector lot derived from 293Vec is suitable to transduce up to 500 patients cell doses in the context of large clinical trials using chimeric antigen receptors or T-cell receptors. These findings demonstrate for the first time that a robust fixed-bed bioreactor process can be used to produce γ-retroviral vector stocks scalable up to the commercialization phase. PMID:25751502

Aeolian process of the dried-up riverbeds of the Hexi Corridor, China: a wind tunnel experiment.

PubMed

Zhang, Caixia; Wang, Xunming; Dong, Zhibao; Hua, Ting

2017-08-01

Wind tunnel studies, which remain limited, are an important tool to understand the aeolian processes of dried-up riverbeds. The particle size, chemical composition, and the mineral contents of sediments arising from the dried river beds are poorly understood. Dried-up riverbeds cover a wide area in the Hexi Corridor, China, and comprise a complex synthesis of different land surfaces, including aeolian deposits, pavement surfaces, and Takyr crust. The results of the present wind tunnel experiment suggest that aeolian transport from the dried-up riverbeds of the Hexi Corridor ranges from 0 to 177.04 g/m 2 /min and that dry riverbeds could be one of the main sources of dust emissions in this region. As soon as the wind velocity reaches 16 m/s and assuming that there are abundant source materials available, aeolian transport intensity increases rapidly. The dried-up riverbed sediment and the associated aeolian transported material were composed mainly of fine and medium sands. However, the transported samples were coarser than the bed samples, because of the sorting effect of the aeolian processes on the sediment. The aeolian processes also led to regional elemental migration and mineral composition variations.

Near-Bed Turbulent Kinetic Energy Budget Under a Large-Scale Plunging Breaking Wave Over a Fixed Bar

NASA Astrophysics Data System (ADS)

van der Zanden, Joep; van der A, Dominic A.; Cáceres, Iván.; Hurther, David; McLelland, Stuart J.; Ribberink, Jan S.; O'Donoghue, Tom

2018-02-01

Hydrodynamics under regular plunging breaking waves over a fixed breaker bar were studied in a large-scale wave flume. A previous paper reported on the outer flow hydrodynamics; the present paper focuses on the turbulence dynamics near the bed (up to 0.10 m from the bed). Velocities were measured with high spatial and temporal resolution using a two component laser Doppler anemometer. The results show that even at close distance from the bed (1 mm), the turbulent kinetic energy (TKE) increases by a factor five between the shoaling, and breaking regions because of invasion of wave breaking turbulence. The sign and phase behavior of the time-dependent Reynolds shear stresses at elevations up to approximately 0.02 m from the bed (roughly twice the elevation of the boundary layer overshoot) are mainly controlled by local bed-shear-generated turbulence, but at higher elevations Reynolds stresses are controlled by wave breaking turbulence. The measurements are subsequently analyzed to investigate the TKE budget at wave-averaged and intrawave time scales. Horizontal and vertical turbulence advection, production, and dissipation are the major terms. A two-dimensional wave-averaged circulation drives advection of wave breaking turbulence through the near-bed layer, resulting in a net downward influx in the bar trough region, followed by seaward advection along the bar's shoreward slope, and an upward outflux above the bar crest. The strongly nonuniform flow across the bar combined with the presence of anisotropic turbulence enhances turbulent production rates near the bed.

Adsorption performance of fixed-bed column for the removal of Fe (II) in groundwater using activated carbon made from palm kernel shells

NASA Astrophysics Data System (ADS)

Sylvia, N.; Hakim, L.; Fardian, N.; Yunardi

2018-03-01

When the manganese is under the acceptable limit, then the removal of Fe (II) ion, the common metallic compound contained in groundwater, is one of the most important stages in the processing of groundwater to become potable water. This study was aimed at investigating the performance of a fixed-bed adsorption column filled, with activated carbon prepared from palm kernel shells, in the removal of Fe (II) ion from groundwater. The influence of important parameters such as bed depth and the flow rate was investigated. The bed depth adsorbent was varied at 7.5, 10 and 12 cm. At a different flow rate of 6, 10 and 14 L/minute. The Atomic Absorb Spectrophotometer was used to measure the Fe (II) ion concentration, thereafter the results were confirmed using a breakthrough curve showing that flow rate and bed depth affected the curve. The mathematical model that used to predict the result was the Thomas and Adams-Bohart model. This model is used to process design, in which predicting time and bed depth needed to meet the breakthrough. This study reveals that the Thomas model was the most appropriate one, including the use of Palm Kernel Shell for processing groundwater. According to the Thomas Model, the highest capacity of adsorption (66.189 mg/g) of 0.169-mg/L of groundwater was achieved with a flow rate of 6 L/minute, with the bed depth at 14 cm.

Ash level meter for a fixed-bed coal gasifier

DOEpatents

Fasching, George E.

1984-01-01

An ash level meter for a fixed-bed coal gasifier is provided which utilizes the known ash level temperature profile to monitor the ash bed level. A bed stirrer which travels up and down through the extent of the bed ash level is modified by installing thermocouples to measure the bed temperature as the stirrer travels through the stirring cycle. The temperature measurement signals are transmitted to an electronic signal process system by an FM/FM telemetry system. The processing system uses the temperature signals together with an analog stirrer position signal, taken from a position transducer disposed to measure the stirrer position to compute the vertical location of the ash zone upper boundary. The circuit determines the fraction of each total stirrer cycle time the stirrer-derived bed temperature is below a selected set point, multiplies this fraction by the average stirrer signal level, multiplies this result by an appropriate constant and adds another constant such that a 1 to 5 volt signal from the processor corresponds to a 0 to 30 inch span of the ash upper boundary level. Three individual counters in the processor store clock counts that are representative of: (1) the time the stirrer temperature is below the set point (500.degree. F.), (2) the time duration of the corresponding stirrer travel cycle, and (3) the corresponding average stirrer vertical position. The inputs to all three counters are disconnected during any period that the stirrer is stopped, eliminating corruption of the measurement by stirrer stoppage.

On-line monitoring of fluid bed granulation by photometric imaging.

PubMed

Soppela, Ira; Antikainen, Osmo; Sandler, Niklas; Yliruusi, Jouko

2014-11-01

This paper introduces and discusses a photometric surface imaging approach for on-line monitoring of fluid bed granulation. Five granule batches consisting of paracetamol and varying amounts of lactose and microcrystalline cellulose were manufactured with an instrumented fluid bed granulator. Photometric images and NIR spectra were continuously captured on-line and particle size information was extracted from them. Also key process parameters were recorded. The images provided direct real-time information on the growth, attrition and packing behaviour of the batches. Moreover, decreasing image brightness in the drying phase was found to indicate granule drying. The changes observed in the image data were also linked to the moisture and temperature profiles of the processes. Combined with complementary process analytical tools, photometric imaging opens up possibilities for improved real-time evaluation fluid bed granulation. Furthermore, images can give valuable insight into the behaviour of excipients or formulations during product development. Copyright © 2014 Elsevier B.V. All rights reserved.

Liquid membrane coated ion-exchange column solids

DOEpatents

Barkey, Dale P.

1988-01-01

This invention relates to a method for improving the performance of liquid membrane separations by coating a liquid membrane onto solid ion-exchange resin beads in a fixed bed. Ion-exchange beads fabricated from an ion-exchange resin are swelled with water and are coated with a liquid membrane material that forms a film over the beads. The beads constitute a fixed bed ion-exchange column. Fluid being treated that contains the desired ion to be trapped by the ion-exchange particle is passed through the column. A carrier molecule, contained in the liquid membrane ion-exchange material, is selective for the desired ion in the fluid. The carrier molecule forms a complex with the desired ion, transporting it through the membrane and thus separating it from the other ions. The solution is fed continuously until breakthrough occurs at which time the ion is recovered, and the bed is regenerated.

Liquid membrane coated ion-exchange column solids

DOEpatents

Barkey, Dale P.

1989-01-01

This invention relates to a method for improving the performance of liquid embrane separations by coating a liquid membrane onto solid ion-exchange resin beads in a fixed bed. Ion-exchange beads fabricated from an ion-exchange resin are swelled with water and are coated with a liquid membrane material that forms a film over the beads. The beads constitute a fixed bed ion-exchange column. Fluid being treated that contains the desired ion to be trapped by the ion-exchange particle is passed through the column. A carrier molecule, contained in the liquid membrane ion-exchange material, is selected for the desired ion in the fluid. The carrier molecule forms a complex with the desired ion, transporting it through the membrane and thus separating it from the other ions. The solution is fed continuously until breakthrough occurs at which time the ion is recovered, and the bed is regenerated.

Fixed-bed column studies of total organic carbon removal from industrial wastewater by use of diatomite decorated with polyethylenimine-functionalized pyroxene nanoparticles.

PubMed

Hethnawi, Afif; Manasrah, Abdallah D; Vitale, Gerardo; Nassar, Nashaat N

2018-03-01

In this study, a fixed-bed column adsorption process was employed to remove organic pollutants from a real industrial wastewater effluent using polyethylenimine-functionalized pyroxene nanoparticles (PEI-PY) embedded into Diatomite at very low mass percentage. Various dynamic parameters (e.g., inlet concentration, inlet flow rate, bed height, and PEI-nanoparticle concentration in Diatomite, (%nps)) were investigated to determine the breakthrough behavior. The obtained breakthrough curves were fit with a convection-dispersion model to determine the characteristic parameters based on mass transfer phenomena. The axial dispersion coefficient (D L ) and group of dimensionless numbers; including Renold number (Re), Schmidt number (Sc), and Sherwood number (Sh) were all determined and correlated by Wilson-Geankoplis correlation that was used to estimate the external film diffusion coefficients (Kc) at 0.0015 < Re<55. Copyright © 2017 Elsevier Inc. All rights reserved.

Rapid Response Concentration-Controlled Desorption of Activated Carbon to Dampen Concentration Fluctuations

DTIC Science & Technology

2007-01-01

Behavior of trickle - bed air biofilter for toluene removal: Effect of non-use periods. Environ. Prog. 2005, 24, 155-161. (3) Martin, F. J.; Loehr, R. C...dampen the fluctuation in acetone concentration at high concentrations. The effect of inlet concentration and empty bed contact time (EBCT) on dampening...oxidizer. The MSA-SST system is a fixed- bed system that rapidly controls the power that heats the adsorbent/adsorbate, resulting in controlled

Potentiality of a fruit peel (banana peel) toward abatement of fluoride from synthetic and underground water samples collected from fluoride affected villages of Birbhum district

NASA Astrophysics Data System (ADS)

Mondal, Naba Kumar; Roy, Arunabha

2018-06-01

Contamination of underground water with fluoride (F) is a tremendous health hazard. Excessive F (> 1.5 mg/L) in drinking water can cause both dental and skeletal fluorosis. A fixed-bed column experiments were carried out with the operating variables such as different initial F concentrations, bed depths, pH and flow rates. Results revealed that the breakthrough time and exhaustion time decrease with increasing flow rate, decreasing bed depth and increasing influent fluoride concentration. The optimized conditions are: 10 mg/L initial fluoride concentration; flow rate 3.4 mL/min, bed depth 3.5 and pH 5. The bed depth service time model and the Thomas model were applied to the experimental results. Both the models were in good agreement with the experimental data for all the process parameters studied except flow rate, indicating that the models were appropriate for removal of F by natural banana peel dust in fix-bed design. Moreover, column adsorption was reversible and the regeneration was accomplished by pumping of 0.1 M NaOH through the loaded banana peel dust column. On the other hand, field water sample analysis data revealed that 86.5% fluoride can be removed under such optimized conditions. From the experimental results, it may be inferred that natural banana peel dust is an effective adsorbent for defluoridation of water.

Responses of experimental river corridors to engineered log jams

USDA-ARS?s Scientific Manuscript database

Physical models of the Big Sioux River, SD, were constructed to assess the impact on flow, drag, and bed erosion and deposition in response to the installation of two different types of engineered log jams (ELJs). A fixed-bed model focused on flow velocity and forces acting on an instrumented ELJ, a...

Propagation of a fluidization - combustion wave

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pron, G.P.; Gusachenko, L.K.; Zarko, V.E.

1994-05-01

A fluidization-combustion wave propagating through a fixed and initially cool bed was created by igniting coal at the top surface of the bed. The proposed physical interpretation of the phenomenon is in qualitative agreement with the experimental dependences of the characteristics of the process on determining parameters. A kindling regime with forced wave propagation is suggested.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khare, G.P.; Delzer, G.A.; Kubicek, D.H.

Phillips Z-Sorb sorbents have been evaluated successfully as regenerable sorbents for hydrogen sulfide in the fuel gas that is produced in a clean coal technology power plant. Tests have been carried out in fixed-,moving-, and fluid-bed applications. The fixed-bed tests completed at the Morgantown Energy Technology Center showed that Phillips Z-Sorb sorbent performed better than zinc titanate. The performance of Phillips Z-Sorb sorbent in a moving-bed application was very encouraging. The sorbent flowed well, H{sub 2}S was reduced to less than 50 ppm at the absorber outlet over long periods and post-test analysis of the sorbent indicated very low sulfatemore » levels at the regenerator exit. The fluidizable version of Phillips Z-Sorb sorbent was tested in Research Triangle Institutes`s high temperature, high pressure, semi-bath, fluidized-bed reactor system. in a life cycle test consisting of 50 cycles of sulfidation and regeneration, this sorbent exhibited excellent activity and regenerability. The sulfur loading was observed to be 90 + percent of the theoretical capacity. The sorbent consistently demonstrated a sharp regeneration profile with no evidence of sulfate accumulation. 7 refs., 7 fig., 5 tabs.« less

Modeling integrated fixed-film activated sludge and moving-bed biofilm reactor systems II: evaluation.

PubMed

Boltz, Joshua P; Johnson, Bruce R; Daigger, Glen T; Sandino, Julian; Elenter, Deborah

2009-06-01

A steady-state model presented by Boltz, Johnson, Daigger, and Sandino (2009) describing integrated fixed-film activated sludge (IFAS) and moving-bed biofilm reactor (MBBR) systems has been demonstrated to simulate, with reasonable accuracy, four wastewater treatment configurations with published operational data. Conditions simulated include combined carbon oxidation and nitrification (both IFAS and MBBR), tertiary nitrification MBBR, and post denitrification IFAS with methanol addition as the external carbon source. Simulation results illustrate that the IFAS/MBBR model is sufficiently accurate for describing ammonia-nitrogen reduction, nitrate/nitrite-nitrogen reduction and production, biofilm and suspended biomass distribution, and sludge production.

Industrial wastewater treatment in a new gas-induced ozone reactor.

PubMed

Lin, Sheng H; Wang, Ching H

2003-03-17

The present work was to investigate industrial wastewater treatment by ozonation in a new gas-induced reactor in conjunction with chemical coagulation pretreatment. The reactor was specifically designed in a fashion that gas induction was created on the liquid surface by the high-speed action of an impeller turbine inside a draft tube to maximize the ozone gas utilization. A new design feature of the present reactor system was a fixed granular activated carbon (GAC) bed packed in a circular compartment between the reactor wall and the shaft tube. The fixed GAC bed provided additional adsorption and catalytic degradation of organic pollutants. Combination of the fixed GAC bed and ozonation results in enhanced oxidation of organic pollutants. In addition to enhanced pollutant oxidation, ozonation was found to provide in situ GAC regeneration that was considered crucial in the present reaction system. Kinetic investigations were also made using a proposed complex kinetic model to elucidate the possible oxidation reaction mechanisms of the present gas-induced ozonation system. As a complementary measure, chemical coagulation pretreatment was found able to achieve up to 50% COD and 85% ADMI removal. Experimental tests were conducted to identify its optimum operating conditions. Copyright 2003 Elsevier Science B.V.

Treatment of mountain refuge wastewater by fixed and moving bed biofilm systems.

PubMed

Andreottola, G; Damiani, E; Foladori, P; Nardelli, P; Ragazzi, M

2003-01-01

Tourists visiting mountain refuges in the Alps have increased significantly in the last decade and the number of refuges and huts at high altitude too. In this research the results of an intensive monitoring of a wastewater treatment plant (WWTP) for a tourist mountain refuge located at 2,981 m a.s.l. are described. Two biofilm reactors were adopted: (a) a Moving Bed Biofilm Reactor (MBBR); (b) a submerged Fixed Bed Biofilm Reactor (FBBR). The aims of this research were: (i) the evaluation of the main parameters characterising the processes and involved in the design of the wastewater plants, in order to compare advantages and disadvantages of the two tested alternatives; (ii) the acquisition of an adequate knowledge of the problems connected with the wastewater treatment in alpine refuges. The main results have been: (i) a quick start-up of the biological reactors obtainable thanks to a pre-colonization before the transportation of the plastic carriers to the refuge at the beginning of the tourist season; (ii) low volume and area requirement; (iii) significantly higher removal efficiency compared to other fixed biomass systems, such as trickling filters, but the energy consumption is higher.

Bed composition generation for morphodynamic modeling: Case study of San Pablo Bay in California, USA

USGS Publications Warehouse

van der Wegen, M.; Dastgheib, A.; Jaffe, B.E.; Roelvink, D.

2011-01-01

Applications of process-based morphodynamic models are often constrained by limited availability of data on bed composition, which may have a considerable impact on the modeled morphodynamic development. One may even distinguish a period of "morphodynamic spin-up" in which the model generates the bed level according to some ill-defined initial bed composition rather than describing the realistic behavior of the system. The present paper proposes a methodology to generate bed composition of multiple sand and/or mud fractions that can act as the initial condition for the process-based numerical model Delft3D. The bed composition generation (BCG) run does not include bed level changes, but does permit the redistribution of multiple sediment fractions over the modeled domain. The model applies the concept of an active layer that may differ in sediment composition above an underlayer with fixed composition. In the case of a BCG run, the bed level is kept constant, whereas the bed composition can change. The approach is applied to San Pablo Bay in California, USA. Model results show that the BCG run reallocates sand and mud fractions over the model domain. Initially, a major sediment reallocation takes place, but development rates decrease in the longer term. Runs that take the outcome of a BCG run as a starting point lead to more gradual morphodynamic development. Sensitivity analysis shows the impact of variations in the morphological factor, the active layer thickness, and wind waves. An important but difficult to characterize criterion for a successful application of a BCG run is that it should not lead to a bed composition that fixes the bed so that it dominates the "natural" morphodynamic development of the system. Future research will focus on a decadal morphodynamic hindcast and comparison with measured bathymetries in San Pablo Bay so that the proposed methodology can be tested and optimized. ?? 2010 The Author(s).

Fundamental aspects related to batch and fixed-bed sulfate sorption by the macroporous type 1 strong base ion exchange resin Purolite A500.

PubMed

Guimarães, Damaris; Leão, Versiane A

2014-12-01

Acid mine drainage is a natural process occurring when sulfide minerals such as pyrite are exposed to water and oxygen. The bacterially catalyzed oxidation of pyrite is particularly common in coal mining operations and usually results in a low-pH water polluted with toxic metals and sulfate. Although high sulfate concentrations can be reduced by gypsum precipitation, removing lower concentrations (below 1200 mg/L) remains a challenge. Therefore, this work sought to investigate the application of ion exchange resins for sulfate sorption. The macroporous type 1 strong base IX resin Purolite A500 was selected for bath and fixed-bed sorption experiments using synthetic sulfate solutions. Equilibrium experiments showed that sulfate loading on the resin can be described by the Langmuir isotherm with a maximum uptake of 59 mg mL-resin(-1). The enthalpy of sorption was determined as +2.83 kJ mol(-1), implying an endothermic physisorption process that occurred with decreasing entropy (-15.5 J mol(-1).K(-1)). Fixed-bed experiments were performed at different bed depths, flow rates, and initial sulfate concentrations. The Miura and Hashimoto model predicted a maximum bed loading of 25-30 g L-bed(-1) and indicated that both film diffusion (3.2 × 10(-3) cm s(-1) to 22.6 × 10(-3) cm s(-1)) and surface diffusion (1.46 × 10(-7) cm(2) s(-1) to 5.64 × 10(-7) cm(2) s(-1)) resistances control the sorption process. It was shown that IX resins are an alternative for the removal of sulfate from mine waters; they ensure very low residual concentrations, particularly in effluents where the sulfate concentration is below the gypsum solubility threshold. Copyright © 2014 Elsevier Ltd. All rights reserved.

Performance of the fixed-bed of granular activated carbon for the removal of pesticides from water supply.

PubMed

Alves, Alcione Aparecida de Almeida; Ruiz, Giselle Louise de Oliveira; Nonato, Thyara Campos Martins; Müller, Laura Cecilia; Sens, Maurício Luiz

2018-02-26

The application of a fixed bed adsorption column of granular activated carbon (FBAC-GAC), in the removal of carbaryl, methomyl and carbofuran at a concentration of 25 μg L -1 for each carbamate, from the public water supply was investigated. For the determination of the presence of pesticides in the water supply, the analytical technique of high-performance liquid chromatography with post-column derivatization was used. Under conditions of constant diffusivity, the FBAC-GAC was saturated after 196 h of operation on a pilot scale. The exhaust rate of the granular activated carbon (GAC) in the FBAC-GAC until the point of saturation was 0.02 kg GAC m -3 of treated water. By comparing a rapid small-scale column test and FBAC-GAC, it was confirmed that the predominant intraparticle diffusivity in the adsorption column was constant diffusivity. Based on the results obtained on a pilot scale, it was possible to estimate the values to be applied in the FBAC-GAC (full scale) to remove the pesticides, which are particle size with an average diameter of 1.5 mm GAC; relationship between the internal diameter of the column and the average diameter of GAC ≥50 in order to avoid preferential flow near the adsorption column wall; surface application rate 240 m 3  m -2  d -1 and an empty bed contact time of 3 min. BV: bed volume; CD: constant diffusivity; EBCT: empty bed contact time; FBAC-GAC: fixed bed adsorption column of granular activated carbon; GAC: granular activated carbon; MPV: maximum permitted values; NOM: natural organic matter; PD: proportional diffusivity; pH PCZ : pH of the zero charge point; SAR: surface application rate; RSSCT: rapid small-scale column test; WTCS: water treated conventional system.

6. VIEW OF POWER PLANT BUILDING LOOKING NORTHWEST. DRY CANAL ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. VIEW OF POWER PLANT BUILDING LOOKING NORTHWEST. DRY CANAL BED TO THE LEFT. - Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 mile upriver from confluence with Shenandoah River, Harpers Ferry, Jefferson County, WV

9. EXTERIOR PERSPECTIVE OF POWER PLANT BUILDING LOOKING NORTHEAST. DRY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

9. EXTERIOR PERSPECTIVE OF POWER PLANT BUILDING LOOKING NORTHEAST. DRY CANAL BED IN FOREGROUND. - Potomac Power Plant, On West Virginia Shore of Potomac River, about 1 mile upriver from confluence with Shenandoah River, Harpers Ferry, Jefferson County, WV

Laboratory Testing of a Fluidized Bed Dry Scrubbing Process for Removal of Sulfur Dioxide and Phosphorous Pentoxide from an Inert Carrier Gas.

DTIC Science & Technology

1988-03-01

flue gas desulfurization . A number of lab-scale studies have been conducted in...data on dry scrubbing of P205 could not be located. However, there is a significant volume of data in the literature on flue gas desulfurization and, to...8217’ ’--- -’ -- ’ -; ’ -’-’ .’ .’’. -’-’ - .".’,-" . ;"> . .. -, " ’. < + i i ,.- F).V A 23 REFERENCE S 1. A. Skopp et al., Fluid Bed Studies of the Limestone Based Flue Gas

Recovery of useful chemicals from palm oil mill wastewater

NASA Astrophysics Data System (ADS)

Ratanaporn, Yuangsawad; Duangkamol, Na-Ranong; Teruoki, Tago; Takao, Masuda

2017-11-01

A two-step process consisting of pyrolysis of dried sludge and catalytic upgrading of pyrolysed liquid was proposed. Wastewater from a palm oil mill was separated to solid cake and liquid by filtration. The solid cake was dried and pyrolysed at 773 K. Liquid product obtained from the pyrolysis had two immiscible aqueous and oil phases (PL-A and PL-O). Identification of chemicals in PL-A and PL-O indicated that both phases contained various chemicals with unsaturated bonds, such as carboxylic acids and alcohols, however, most of the chemicals could not be identified. Catalytic upgrading of PL-A and PL-O over ZrO2·FeOx were separately performed using a fixed bed reactor at various conditions, T = 513-723 K and mass of catalyst to feed rate = 0.25-10 h. The main components in the liquid products of PL-A upgrading were methanol and acetone whereas they were acetone and phenol in the case of PL-O upgrading. More than 15% of carbon in raw material was deposited on the catalyst. To reduce the carbon deposition, the used catalyst was treated with air at 823 K. This simple treatment could reasonably regenerate the catalyst only for the case of PL-A catalytic upgrading.

Gravimetric measurement of momentary drying rate of spray freeze-dried powders in vials.

PubMed

Gieseler, Henning; Lee, Geoffrey

2009-09-01

The profile of drying rate versus primary drying time for a spray freeze-dried trehalose aqueous solution is much different from that determined for regular freeze-drying. Drying rate declines very rapidly, attributed to rate-limiting heat transfer through the packed bed of frozen microparticles contained in a vial. The inter-particulate spaces appear to be the cause of this rate limitation. Use of either liquid nitrogen or liquid propane as a cryogenic produced strong differences in both SFD particle morphology and drying rate using trehalose, sucrose, or mannitol. The lack of any evident correlation supports the argument that the inter-particulate voids determine drying behavior.

Material handling systems for the fluidized-bed combustion boiler at Rivesville, West Virginia

NASA Technical Reports Server (NTRS)

Branam, J. G.; Rosborough, W. W.

1977-01-01

The 300,000 lbs/hr steam capacity multicell fluidized-bed boiler (MFB) utilizes complex material handling systems. The material handling systems can be divided into the following areas: (1) coal preparation; transfer and delivery, (2) limestone handling system, (3) fly-ash removal and (4) bed material handling system. Each of the above systems are described in detail and some of the potential problem areas are discussed. A major potential problem that exists is the coal drying system. The coal dryer is designed to use 600 F preheated combustion air as drying medium and the dryer effluent is designed to enter a hot electrostatic precipitator (730 F) after passage through a cyclone. Other problem areas to be discussed include the steam generator coal and limestone feed system which may have operating difficulties with wet coal and/or coal fines.

Trace contaminant adsorption and sorbent regeneration in closed ecological systems

NASA Technical Reports Server (NTRS)

Arnold, C. R.; Kersels, G. J.; Merrill, R. P.; Robell, A. J.; Wheeler, A.

1972-01-01

Correlation was obtained for determining sorptive capacity of carbon for pure and mixed contaminants under dry and humid conditions at various temperatures. Vacuum desorption rates were investigated for single particles and for sorbent beds. For sorbent beds, rate-determining step is Knudsen diffusion through interparticle voids.

A fuzzy-logic-based controller for methane production in anaerobic fixed-film reactors.

PubMed

Robles, A; Latrille, E; Ruano, M V; Steyer, J P

2017-01-01

The main objective of this work was to develop a controller for biogas production in continuous anaerobic fixed-bed reactors, which used effluent total volatile fatty acids (VFA) concentration as control input in order to prevent process acidification at closed loop. To this aim, a fuzzy-logic-based control system was developed, tuned and validated in an anaerobic fixed-bed reactor at pilot scale that treated industrial winery wastewater. The proposed controller varied the flow rate of wastewater entering the system as a function of the gaseous outflow rate of methane and VFA concentration. Simulation results show that the proposed controller is capable to achieve great process stability even when operating at high VFA concentrations. Pilot results showed the potential of this control approach to maintain the process working properly under similar conditions to the ones expected at full-scale plants.

Coal-feeding mechanism for a fluidized bed combustion chamber

DOEpatents

Gall, Robert L.

1981-01-01

The present invention is directed to a fuel-feeding mechanism for a fluidized bed combustor. In accordance with the present invention a perforated conveyor belt is utilized in place of the fixed grid normally disposed at the lower end of the fluidized bed combustion zone. The conveyor belt is fed with fuel, e.g. coal, at one end thereof so that the air passing through the perforations dislodges the coal from the belt and feeds the coal into the fluidized zone in a substantially uniform manner.

First post-fire flush in a Mediterranean temporary stream: source ascription in bed sediments

NASA Astrophysics Data System (ADS)

Estrany Bertos, Joan; García-Comendador, Julián; Fortesa, Josep; Calsamiglia, Aleix; Garcias, Francesca

2017-04-01

First flushes can be of great importance for suspended-sediment transport in fluvial systems of drylands, being temporary streams a characteristic feature of Mediterranean basins. After a wildfire, storm flows may enhance runoff delivery to channels and then increasing the first-flush effect. 137Cs and 210Pbex were used as tracers for recognizing the first post-fire flush effect in the source ascription of bed sediments temporarily stored in a Mediterranean temporary stream severely affected by a wildfire. Thirty potential sediment source samples were collected along the main stem of a catchment located in Mallorca (Spain) during a field campaign developed some weeks after the wildfire. The sample collection was designed considering the wildfire affection, and also distinguishing between soil surface and channel bank. To quantify the relative source contribution to the bed sediment temporarily stored, five sediment samples -deposited during the first storm occurred three months after the wildfire- were collected into the bed stream of the main channel. The 137Cs and 210Pbex concentrations were measured by gamma spectrometry. Then, a linear mixing model was used to establish the relative contribution of each source type to the bed sediments discerning between the most upstream and the downstream parts of the catchment. Post-fire first-flush effect was generated by a torrential event with a suspended-sediment concentration peak ca. 33,618 mg L-1, although transmission losses under a very low runoff coefficient (1%) promoted sediment deposition. Significant differences were observed in fallout radionuclide concentrations between burned surface soil and channel bank samples (p < 0.05), as well as between burned and unburned sources at the downstream part of the catchment (p < 0.01). The radioactivity concentrations in bed sediments samples were statistically similar (p > 0.05). Source ascription in bed sediments in the middle stream shows that 67% was generated in burned hillslopes, reaching 75% in the downstream part because downstream propagation of the sediment derived from the burned area. Bed sediments were mostly generated in burned hillslopes because of the fire effects on soils and sediment availability, high intensity rainfall and limited contribution of channel banks that are fixed by dry-stone walls. This hydro-sedimentary response indicates an association between driven sediment transport factors and sediment availability, generating an effective slope-to-channel sediment connectivity. Long-term sediment sources monitoring will elucidate if the most effective period of the window of disturbance at catchment scale is further extended (i.e., ≈5 years).

Packed-bed catalytic cracking of oak derived pyrolytic vapors

USDA-ARS?s Scientific Manuscript database

Catalytic upgrading of pyrolysis vapors derived from oak was carried out using a fixed-bed catalytic column at 425 deg C. The vapors were drawn by splitting a fraction from the full stream of vapors produced at 500 deg C in a 5 kg/hr bench-scale fast pyrolysis reactor system downstream the cyclone s...

40 CFR 264.1033 - Standards: Closed-vent systems and control devices.

Code of Federal Regulations, 2011 CFR

2011-07-01

... condenser exit (i.e., product side). (vii) For a carbon adsorption system that regenerates the carbon bed... requirements of this section. (g) An owner or operator using a -carbon adsorption system such as a fixed-bed...)(F). (h) An owner or operator using a carbon adsorption system such as a carbon canister that does...

High efficiency power generation from coal and wastes utilizing high temperature air combustion technology (Part 1: Performance of pebble bed gasifier for coal and wastes)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kosaka, Hitoshi; Iwahashi, Takashi; Yoshida, Nobuhiro

1998-07-01

A new concept of a gasifier for coal and wastes is proposed where entrained bed and fixed pebble bed are combined. Main features of this pebble bed gasifier are high efficiency molten slag capture, high efficiency gasification and compactness. Coal and RFD combustion experiments using the pebble bed gasifier demonstrated high efficiency capture and continuous extraction of molten slag as well as complete char combustion with extra ordinarily short residence time of pulverized coal and crushed RDF at the temperature level of about 1,500 C within the pebble bed. Durability tests using high temperature electric furnace has shown that highmore » density alumna is a good candidate for pebble material.« less

Paired Straight Hearth Furnace - Transformational Ironmaking Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Wei-Kao; Debski, Paul

2014-11-19

The U. S. steel industry has reduced its energy intensity per ton of steel shipped by 33% since 1990. However, further significant gains in energy efficiency will require the development of new, transformational iron and steelmaking processes. The Paired Straight Hearth Furnace (PSH) process is an emerging alternative high productivity, direct reduced iron (DRI) technology that may achieve very low fuel rates and has the potential to replace blast furnace ironmaking. The PSH furnace can operate independently or may be coupled with other melting technologies to produce liquid hot metal that is both similar to blast furnace iron and suitablemore » as a feedstock for basic oxygen steelmaking furnaces. The PSH process uses non-metallurgical coal as a reductant to convert iron oxides such as iron ore and steelmaking by-product oxides to DRI pellets. In this process, a multi-layer, nominally 120mm tall bed of composite “green balls” made from oxide, coal and binder is built up and contained within a moving refractory hearth. The pellet bed absorbs radiant heat energy during exposure to the high temperature interior refractory surfaces of the PSH while generating a strongly reducing gas atmosphere in the bed that yields a highly metalized DRI product. The PSH concept has been well tested in static hearth experiments. A moving bed design is being developed. The process developers believe that if successful, the PSH process has the potential to replace blast furnaces and coke ovens at a fraction of the operating and capital cost while using about 30% less energy relative to current blast furnace technology. DRI output could also feed electric arc furnaces (EAFs) by displacing a portion of the scrap charge.« less

Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

NASA Astrophysics Data System (ADS)

Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

2017-02-01

Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal.

Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater.

PubMed

Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

2017-02-20

Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal.

Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

PubMed Central

Ahmadi, Ehsan; Yousefzadeh, Samira; Ansari, Mohsen; Ghaffari, Hamid Reza; Azari, Ali; Miri, Mohammad; Mesdaghinia, Alireza; Nabizadeh, Ramin; Kakavandi, Babak; Ahmadi, Peyman; Badi, Mojtaba Yegane; Gholami, Mitra; Sharafi, Kiomars; Karimaei, Mostafa; Ghoochani, Mahboobeh; Brahmand, Masoud Binesh; Mohseni, Seyed Mohsen; Sarkhosh, Maryam; Rezaei, Soheila; Asgharnia, Hosseinali; Dehghanifard, Emad; Jafari, Behdad; Mortezapour, Alireza; Moghaddam, Vahid Kazemi; Mahmoudi, Mohammad Molla; Taghipour, Nader

2017-01-01

Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal. PMID:28216654

SOURCES OF PCBS TO THE ATMOSPHERE IN CHICAGO

EPA Science Inventory

The project will obtain additional short-term PCB samples in southwestern Chicago to determine the amount of PCB emissions to the air from a sludge drying facility. Four different types of samples will be collected: (1) short-term ambient air samples surrounding the drying beds,...

Analysis of fixed bed data for the extraction of a rate mechanism for the reaction of hematite with methane

DOE PAGES

Breault, Ronald W.; Monazam, Esmail R.

2015-04-01

In this study, chemical looping combustion is a promising technology for the capture of CO 2 involving redox materials as oxygen carriers. The effects of reduction conditions, namely, temperature and fuel partial pressure on the conversion products are investigated. The experiments were conducted in a laboratory fixed-bed reactor that was operated cyclically with alternating reduction and oxidation periods. Reactions are assumed to occur in the shell surrounding the particle grains with diffusion of oxygen to the surface from the grain core. Activation energies for the shell and core reactions range from 9 to 209 kJ/mol depending on the reaction step.

Using Mechanical Energy as a Probe for the Detection and Imaging of Shallow Buried Inclusions in Dry Granular Beds

NASA Astrophysics Data System (ADS)

Sen, Surajit; Krishna Mohan, T. R.; Visco, Donald P.; Swaminathan, Saravanan; Sokolow, Adam; Avalos, Edgar; Nakagawa, Masami

Mechanical energy, such as sound waves and impulses, have been used to detect shallow buried objects for more than half a century. Yet, very little is understood about how mechanical energy propagates into one of the simplest kinds of soil, namely, a granular bed. Here we present an overview of the state of the art in our understanding of mechanical energy propagation in granular beds.

Forces on stationary particles in near-bed turbulent flows

NASA Astrophysics Data System (ADS)

Schmeeckle, Mark W.; Nelson, Jonathan M.; Shreve, Ronald L.

2007-06-01

In natural flows, bed sediment particles are entrained and moved by the fluctuating forces, such as lift and drag, exerted by the overlying flow on the particles. To develop a better understanding of these forces and the relation of the forces to the local flow, the downstream and vertical components of force on near-bed fixed particles and of fluid velocity above or in front of them were measured synchronously at turbulence-resolving frequencies (200 or 500 Hz) in a laboratory flume. Measurements were made for a spherical test particle fixed at various heights above a smooth bed, above a smooth bed downstream of a downstream-facing step, and in a gravel bed of similarly sized particles as well as for a cubical test particle and 7 natural particles above a smooth bed. Horizontal force was well correlated with downstream velocity and not correlated with vertical velocity or vertical momentum flux. The standard drag formula worked well to predict the horizontal force, but the required value of the drag coefficient was significantly higher than generally used to model bed load motion. For the spheres, cubes, and natural particles, average drag coefficients were found to be 0.76, 1.36, and 0.91, respectively. For comparison, the drag coefficient for a sphere settling in still water at similar particle Reynolds numbers is only about 0.4. The variability of the horizontal force relative to its mean was strongly increased by the presence of the step and the gravel bed. Peak deviations were about 30% of the mean force for the sphere over the smooth bed, about twice the mean with the step, and 4 times it for the sphere protruding roughly half its diameter above the gravel bed. Vertical force correlated poorly with downstream velocity, vertical velocity, and vertical momentum flux whether measured over or ahead of the test particle. Typical formulas for shear-induced lift based on Bernoulli's principle poorly predict the vertical forces on near-bed particles. The measurements suggest that particle-scale pressure variations associated with turbulence are significant in the particle momentum balance.

Forces on stationary particles in near-bed turbulent flows

USGS Publications Warehouse

Schmeeckle, M.W.; Nelson, J.M.; Shreve, R.L.

2007-01-01

In natural flows, bed sediment particles are entrained and moved by the fluctuating forces, such as lift and drag, exerted by the overlying flow on the particles. To develop a better understanding of these forces and the relation of the forces to the local flow, the downstream and vertical components of force on near-bed fixed particles and of fluid velocity above or in front of them were measured synchronously at turbulence-resolving frequencies (200 or 500 Hz) in a laboratory flume. Measurements were made for a spherical test particle fixed at various heights above a smooth bed, above a smooth bed downstream of a downstream-facing step, and in a gravel bed of similarly sized particles as well as for a cubical test particle and 7 natural particles above a smooth bed. Horizontal force was well correlated with downstream velocity and not correlated with vertical velocity or vertical momentum flux. The standard drag formula worked well to predict the horizontal force, but the required value of the drag coefficient was significantly higher than generally used to model bed load motion. For the spheres, cubes, and natural particles, average drag coefficients were found to be 0.76, 1.36, and 0.91, respectively. For comparison, the drag coefficient for a sphere settling in still water at similar particle Reynolds numbers is only about 0.4. The variability of the horizontal force relative to its mean was strongly increased by the presence of the step and the gravel bed. Peak deviations were about 30% of the mean force for the sphere over the smooth bed, about twice the mean with the step, and 4 times it for the sphere protruding roughly half its diameter above the gravel bed. Vertical force correlated poorly with downstream velocity, vertical velocity, and vertical momentum flux whether measured over or ahead of the test particle. Typical formulas for shear-induced lift based on Bernoulli's principle poorly predict the vertical forces on near-bed particles. The measurements suggest that particle-scale pressure variations associated with turbulence are significant in the particle momentum balance. Copyright 2007 by the American Geophysical Union.

Packed-bed column biosorption of chromium(VI) and nickel(II) onto Fenton modified Hydrilla verticillata dried biomass.

PubMed

Mishra, Ashutosh; Tripathi, Brahma Dutt; Rai, Ashwani Kumar

2016-10-01

The present study represents the first attempt to investigate the biosorption potential of Fenton modified Hydrilla verticillata dried biomass (FMB) in removing chromium(VI) and nickel(II) ions from wastewater using up-flow packed-bed column reactor. Effects of different packed-bed column parameters such as bed height, flow rate, influent metal ion concentration and particle size were examined. The outcome of the column experiments illustrated that highest bed height (25cm); lowest flow rate (10mLmin(-1)), lowest influent metal concentration (5mgL(-1)) and smallest particle size range (0.25-0.50mm) are favourable for biosorption. The maximum biosorption capacity of FMB for chromium(VI) and nickel(II) removal were estimated to be 89.32 and 87.18mgg(-1) respectively. The breakthrough curves were analyzed using Bed Depth Service Time (BDST) and Thomas models. The experimental results obtained agree to both the models. Column regeneration experiments were also carried out using 0.1M HNO3. Results revealed good reusability of FMB during ten cycles of sorption and desorption. Performance of FMB-packed column in treating secondary effluent was also tested under identical experimental conditions. Results demonstrated significant reduction in chromium(VI) and nickel(II) ions concentration after the biosorption process. Copyright © 2016 Elsevier Inc. All rights reserved.

Impacts of tilling and covering treatments on the biosolids solar drying conversion from Class B to Class A

USDA-ARS?s Scientific Manuscript database

The objective of this study was to evaluate the effects of tillage and cover treatments of solar drying on the conversion of Class B treated sewage sludge to a Class A product. The experiments were performed over two years at Green Valley, Arizona in steel-constructed sand-filled drying beds of 1.0m...

Preliminary CFD study of Pebble Size and its Effect on Heat Transfer in a Pebble Bed Reactor

NASA Astrophysics Data System (ADS)

Jones, Andrew; Enriquez, Christian; Spangler, Julian; Yee, Tein; Park, Jungkyu; Farfan, Eduardo

2017-11-01

In pebble bed reactors, the typical pebble diameter used is 6cm, and within each pebble is are thousands of nuclear fuel kernels. However, efficiency of the reactor does not solely depend on the number of kernels of fuel within each graphite sphere, but also depends on the type and motion of the coolant within the voids between the spheres and the reactor itself. In this work a physical analysis of the pebble bed nuclear reactor's fluid dynamics is undertaken using Computational Fluid Dynamics software. The primary goal of this work is to observe the relationship between the different pebble diameters in an idealized alignment and the thermal transport efficiency of the reactor. The model constructed of our idealized argument will consist on stacked 8 pebble columns that fixed at the inlet on the reactor. Two different pebble sizes 4 cm and 6 cm will be studied and helium will be supplied as coolant with a fixed flow rate of 96 kg/s, also a fixed pebble surface temperatures will be used. Comparison will then be made to evaluate the efficiency of coolant to transport heat due to the varying sizes of the pebbles. Assistant Professor for the Department of Civil and Construction Engineering PhD.

Fundamental Studies on Two-Phase Gas-Liquid Flows Through Packed Beds in Microgravity

NASA Technical Reports Server (NTRS)

Balakotaiah, Vemuri; McCready, Mark J.; Motil, Brian J.

2002-01-01

In the typical operation of a packed-bed reactor, gas and liquid flow simultaneously through a fixed bed of solid particles. Depending on the application, the particles can be of various shapes and sizes and provide for intimate contact and high rates of transport between the phases needed to sustain chemical or biological reactions. The packing may also serve as either a catalyst or as a support for growing biological material. NASA has flown two of these packed-bed systems in a microgravity environment with limited or no success. The goal of this research is to develop models (with scale-up capability) needed for the design of the physicochemical equipment to carry out these unit operations in microgravity. New insight will also lead to improvements in normal gravity operations. Our initial experiment was flown using an existing KC-135 two-phase flow rig with a modified test section. The test section is a clear polycarbonate rectangular column with a depth of 2.54 cm, a width of 5.08 cm, and 60 cm long. The column was randomly packed with spherical glass beads by slowly dropping the beads into the bed. Even though care was taken in handling the column after it was filled with packing, the alternating high and low gravity cycles with each parabola created a slightly tighter packed bed than is typically reported for this type. By the usual method of comparing the weight difference of a completely dry column versus a column filled with water, the void fraction was found to be .345 for both sizes of beads used. Five flush mounted differential pressure transducers are spaced at even intervals with the first location 4 cm from the inlet port and the subsequent pressure transducers spaced at 13 cm intervals along the column. Differential pressure data was acquired at 1000 Hz to adequately observe pulse formation and characteristics. Visual images of the flow were recorded using a high-speed SVHS system at 500 frames per second. Over 250 different test conditions were evaluated along with a companion set of tests in normal gravity. The flow rates, fluid properties and packing properties were selected to provide a range of several orders-of-magnitude for the important dimensionless parameters. Additional information is included in the original extended abstract.

Factors influencing the nitrification efficiency of fluidized bed filter with a plastic bead medium

USGS Publications Warehouse

Sandu, S.I.; Boardman, G.D.; Watten, B.J.; Brazil, B.L.

2002-01-01

The performance of fluidized bed nitrification filters charged with 2 ?? 4 ABS plastic beads (specific gravity 1.06) was evaluated. Three unique bed-height to diameter ratios were established, in triplicate, using column diameters of 12.7, 15.2 and 17.8 cm. Filters received water spiked with recycled nutrients and ammonia (TAN), from one of the three 500 1 feed tank system. With daily ammonia loading fixed at 8.6 g per system, TAN removal increased with column diameter at each of four tests hydraulic loading rates (6, 8, 10 and 12 Lpm). TAN in recirculated water (influent) rose from 0.5 to 1.0 mg/1 as ammonia loading increased from 180 mg/m2-day to 360 mg/m2-day. When hydraulic loading was fixed at 12 Lpm, TAN removal (%) was maximized with ammonia loadings ranging from 225 to 270 mg/m2-day. Biofilm thickness increased with ammonia loading, but decreased with increased hydraulic loading rates. Fluidized beds of ABS plastic beads were effective in reducing energy costs (head loss) of water treatment. ?? 2002 Elsevier Science B.V. All rights reserved.

Effects of temperature, pressure, and carrier gas on the cracking of coal tar over a char-dolomite mixtures and calcined dolomite in a fixed-bed reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seshadri, K.; Shamsi, A.

1998-10-01

A distillation fraction of a coal-derived liquid (tar) was cracked over a char-dolomite mixture, calcined dolomite, and silicon carbide in a fixed-bed reactor. The char-dolomite mixture (FWC) was produced from Pittsburgh No. 8 coal and dolomite in a Foster Wheeler carbonizer. The experiments were conducted under nitrogen and simulated coal gas (SCG), which was a mixture of CO, CO{sub 2}, H{sub 2}S, CH{sub 4}, N{sub 2}, and steam, at 1 and 17 atm. The conversion over these materials under nitrogen was much higher at 17 atm than at 1 atm. At higher pressures, tar molecules were trapped in the poresmore » of the bed material and underwent secondary reactions, resulting in the formation of excess char. However, when nitrogen was replaced by SCG, the reactions that induce char formation were suppressed, thus increasing the yield of gaseous products. The analysis of the gaseous products and the spent bed materials for organic and inorganic carbons suggested that the product distribution can be altered by changing the carrier gas, temperature, and pressure.« less

Statistical estimate of mercury removal efficiencies for air pollution control devices of municipal solid waste incinerators.

PubMed

Takahashi, Fumitake; Kida, Akiko; Shimaoka, Takayuki

2010-10-15

Although representative removal efficiencies of gaseous mercury for air pollution control devices (APCDs) are important to prepare more reliable atmospheric emission inventories of mercury, they have been still uncertain because they depend sensitively on many factors like the type of APCDs, gas temperature, and mercury speciation. In this study, representative removal efficiencies of gaseous mercury for several types of APCDs of municipal solid waste incineration (MSWI) were offered using a statistical method. 534 data of mercury removal efficiencies for APCDs used in MSWI were collected. APCDs were categorized as fixed-bed absorber (FA), wet scrubber (WS), electrostatic precipitator (ESP), and fabric filter (FF), and their hybrid systems. Data series of all APCD types had Gaussian log-normality. The average removal efficiency with a 95% confidence interval for each APCD was estimated. The FA, WS, and FF with carbon and/or dry sorbent injection systems had 75% to 82% average removal efficiencies. On the other hand, the ESP with/without dry sorbent injection had lower removal efficiencies of up to 22%. The type of dry sorbent injection in the FF system, dry or semi-dry, did not make more than 1% difference to the removal efficiency. The injection of activated carbon and carbon-containing fly ash in the FF system made less than 3% difference. Estimation errors of removal efficiency were especially high for the ESP. The national average of removal efficiency of APCDs in Japanese MSWI plants was estimated on the basis of incineration capacity. Owing to the replacement of old APCDs for dioxin control, the national average removal efficiency increased from 34.5% in 1991 to 92.5% in 2003. This resulted in an additional reduction of about 0.86Mg emission in 2003. Further study using the methodology in this study to other important emission sources like coal-fired power plants will contribute to better emission inventories. Copyright © 2010 Elsevier B.V. All rights reserved.

The influence of process parameters in production of lipopeptide iturin A using aerated packed bed bioreactors in solid-state fermentation.

PubMed

Piedrahíta-Aguirre, C A; Bastos, R G; Carvalho, A L; Monte Alegre, R

2014-08-01

The strain Bacillus iso 1 co-produces the lipopeptide iturin A and biopolymer poly-γ-glutamic acid (γ-PGA) in solid-state fermentation of substrate consisting of soybean meal, wheat bran with rice husks as an inert support. The effects of pressure drop, oxygen consumption, medium permeability and temperature profile were studied in an aerated packed bed bioreactor to produce iturin A, diameter of which was 50 mm and bed height 300 mm. The highest concentrations of iturin A and γ-PGA were 5.58 and 3.58 g/kg-dry substrate, respectively, at 0.4 L/min after 96 h of fermentation. The low oxygen uptake rates, being 23.34 and 22.56 mg O2/kg-dry solid substrate for each air flow rate tested generated 5.75 W/kg-dry substrate that increased the fermentation temperature at 3.7 °C. The highest pressure drop was 561 Pa/m at 0.8 L/min in 24 h. This is the highest concentration of iturin A produced to date in an aerated packed bed bioreactor in solid-state fermentation. The results can be useful to design strategies to scale-up process of iturin A in aerated packed bed bioreactors. Low concentration of γ-PGA affected seriously pressure drop, decreasing the viability of the process due to generation of huge pressure gradients with volumetric air flow rates. Also, the low oxygenation favored the iturin A production due to the reduction of free void by γ-PGA production, and finally, the low oxygen consumption generated low metabolic heat. The results show that it must control the pressure gradients to scale-up the process of iturin A production.

Forming MOFs into spheres by use of molecular gastronomy methods.

PubMed

Spjelkavik, Aud I; Aarti; Divekar, Swapnil; Didriksen, Terje; Blom, Richard

2014-07-14

A novel method utilizing hydrocolloids to prepare nicely shaped spheres of metal-organic frameworks (MOFs) has been developed. Microcrystalline CPO-27-Ni particles are dispersed in either alginate or chitosan solutions, which are added dropwise to solutions containing, respectively, either divalent group 2 cations or base that act as gelling agents. Well-shaped spheres are immediately formed, which can be dried into spheres containing mainly MOF (>95 wt %). The spheronizing procedures have been optimized with respect to maximum specific surface area, shape, and particle density of the final sphere. At optimal conditions, well-shaped 2.5-3.5 mm diameter CPO-27-Ni spheres with weight-specific surface areas <10 % lower than the nonformulated CPO-27-Ni precursor, and having sphere densities in the range 0.8 to 0.9 g cm(-3) and particle crushing strengths above 20 N, can be obtained. The spheres are well suited for use in fixed-bed catalytic or adsorption processes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Moving bed reactor setup to study complex gas-solid reactions.

PubMed

Gupta, Puneet; Velazquez-Vargas, Luis G; Valentine, Charles; Fan, Liang-Shih

2007-08-01

A moving bed scale reactor setup for studying complex gas-solid reactions has been designed in order to obtain kinetic data for scale-up purpose. In this bench scale reactor setup, gas and solid reactants can be contacted in a cocurrent and countercurrent manner at high temperatures. Gas and solid sampling can be performed through the reactor bed with their composition profiles determined at steady state. The reactor setup can be used to evaluate and corroborate model parameters accounting for intrinsic reaction rates in both simple and complex gas-solid reaction systems. The moving bed design allows experimentation over a variety of gas and solid compositions in a single experiment unlike differential bed reactors where the gas composition is usually fixed. The data obtained from the reactor can also be used for direct scale-up of designs for moving bed reactors.

A model for complex flows of soft glassy materials with application to flows through fixed fiber beds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarkar, Arijit; Koch, Donald L., E-mail: dlk15@cornell.edu

2015-11-15

The soft glassy rheology (SGR) model has successfully described the time dependent simple shear rheology of a broad class of complex fluids including foams, concentrated emulsions, colloidal glasses, and solvent-free nanoparticle-organic hybrid materials (NOHMs). The model considers a distribution of mesoscopic fluid elements that hop from trap to trap at a rate which is enhanced by the work done to strain the fluid element. While an SGR fluid has a broad exponential distribution of trap energies, the rheology of NOHMs is better described by a narrower energy distribution and we consider both types of trap energy distributions in this study.more » We introduce a tensorial version of these models with a hopping rate that depends on the orientation of the element relative to the mean stress field, allowing a range of relative strengths of the extensional and simple shear responses of the fluid. As an application of these models we consider the flow of a soft glassy material through a dilute fixed bed of fibers. The dilute fixed bed exhibits a range of local linear flows which alternate in a chaotic manner with time in a Lagrangian reference frame. It is amenable to an analytical treatment and has been used to characterize the strong flow response of many complex fluids including fiber suspensions, dilute polymer solutions and emulsions. We show that the accumulated strain in the fluid elements has an abrupt nonlinear growth at a Deborah number of order one in a manner similar to that observed for polymer solutions. The exponential dependence of the hopping rate on strain leads to a fluid element deformation that grows logarithmically with Deborah number at high Deborah numbers. SGR fluids having a broad range of trap energies flowing through fixed beds can exhibit a range of rheological behaviors at small Deborah numbers ranging from a yield stress, to a power law response and finally to Newtonian behavior.« less

TiO2-photocatalyzed As(III) oxidation in a fixed-bed, flow-through reactor.

PubMed

Ferguson, Megan A; Hering, Janet G

2006-07-01

Compliance with the U.S. drinking water standard for arsenic (As) of 10 microg L(-1) is required in January 2006. This will necessitate implementation of treatment technologies for As removal by thousands of water suppliers. Although a variety of such technologies is available, most require preoxidation of As(III) to As(V) for efficient performance. Previous batch studies with illuminated TiO2 slurries have demonstrated that TiO2-photocatalyzed AS(III) oxidation occurs rapidly. This study examined reaction efficiency in a flow-through, fixed-bed reactor that provides a better model for treatment in practice. Glass beads were coated with mixed P25/sol gel TiO2 and employed in an upflow reactor irradiated from above. The reactor residence time, influent As(III) concentration, number of TiO2 coatings on the beads, solution matrix, and light source were varied to characterize this reaction and determine its feasibility for water treatment. Repeated usage of the same beads in multiple experiments or extended use was found to affect effluent As(V) concentrations but not the steady-state effluent As(III) concentration, which suggests that As(III) oxidation at the TiO2 surface undergoes dynamic sorption equilibration. Catalyst poisoning was not observed either from As(V) or from competitively adsorbing anions, although the higher steady-state effluent As(III) concentrations in synthetic groundwater compared to 5 mM NaNO3 indicated that competitive sorbates in the matrix partially hinder the reaction. A reactive transport model with rate constants proportional to incident light at each bead layer fit the experimental data well despite simplifying assumptions. TiO2-photocatalyzed oxidation of As(III) was also effective under natural sunlight. Limitations to the efficiency of As(III) oxidation in the fixed-bed reactor were attributable to constraints of the reactor geometry, which could be overcome by improved design. The fixed-bed TiO2 reactor offers an environmentally benign method for As(III) oxidation.

Arsenic removal via ZVI in a hybrid spouted vessel/fixed bed filter system

PubMed Central

Calo, Joseph M.; Madhavan, Lakshmi; Kirchner, Johannes; Bain, Euan J.

2012-01-01

The description and operation of a novel, hybrid spouted vessel/fixed bed filter system for the removal of arsenic from water are presented. The system utilizes zero-valent iron (ZVI) particles circulating in a spouted vessel that continuously generates active colloidal iron corrosion products via the “self-polishing” action between ZVI source particles rolling in the moving bed that forms on the conical bottom of the spouted vessel. This action also serves as a “surface renewal” mechanism for the particles that provides for maximum utilization of the ZVI material. (Results of batch experiments conducted to examine this mechanism are also presented.) The colloidal material produced in this fashion is continuously captured and concentrated in a fixed bed filter located within the spouted vessel reservoir wherein arsenic complexation occurs. It is demonstrated that this system is very effective for arsenic removal in the microgram per liter arsenic concentration (i.e., drinking water treatment) range, reducing 100 μg/L of arsenic to below detectable levels (≪10 μg/L) in less than an hour. A mechanistic analysis of arsenic behavior in the system is presented, identifying the principal components of the population of active colloidal material for arsenic removal that explains the experimental observations and working principles of the system. It is concluded that the apparent kinetic behavior of arsenic in systems where colloidal (i.e., micro/nano) iron corrosion products are dominant can be complex and may not be explained by simple first or zeroth order kinetics. PMID:22539917

In situ magnetic resonance measurement of conversion, hydrodynamics and mass transfer during single- and two-phase flow in fixed-bed reactors.

PubMed

Gladden, L F; Alexander, P; Britton, M M; Mantle, M D; Sederman, A J; Yuen, E H L

2003-01-01

In recent years there has been increasing interest in applying magnetic resonance (MR) techniques in areas of engineering and chemical technology. The science that underpins many of these applications is the physics and chemistry of transport and reaction processes in porous materials. Key to the exploitation of MR methods will be our ability to demonstrate that MR yields information that cannot be obtained using conventional measurement techniques in engineering research. This article describes two case studies that highlight the power of MR to give new insights to chemical engineers. First, we demonstrate the application of MR techniques to explore both mass transfer and chemical conversion in situ within a fixed bed of catalyst, and we then use these data to identify the rate-controlling step of the chemical conversion. Second, we implement a rapid imaging technique to study the stability of the gas-liquid distribution in the low- and high-interaction two-phase flow regimes in a trickle-bed reactor.

Fixed bed pyrolysis of biomass solid waste for bio-oil

NASA Astrophysics Data System (ADS)

Islam, Mohammad Nurul; Ali, Mohamed Hairol Md; Haziq, Miftah

2017-08-01

Biomass solid waste in the form of rice husk particle is pyrolyzed in a fixed bed stainless steel pyrolysis reactor of 50 mm diameter and 50 cm length. The biomass solid feedstock is prepared prior to pyrolysis. The reactor bed is heated by means of a cylindrical heater of biomass source. A temperature of 500°C is maintained with an apperent vapor residence time of 3-5 sec. The products obtained are liquid bio-oil, solid char and gases. The liquid product yield is found to be 30% by weight of solid biomass feedstock while the solid product yield is found to be 35% by weight of solid biomass feedtock, the rest is gas. The bio-oil is a single-phase brownish color liquid of acrid smell. The heating value of the oil is determined to be 25 MJ/kg. The density and pH value are found to be 1.125 kg/m3 and 3.78 respectively.

Fixed Bed Column Study for Adsolubilization of 2,4-D Herbicide on Surfactant Modified Silica Gel Waste

NASA Astrophysics Data System (ADS)

Koner, S.; Adak, A.

2012-09-01

The fixed bed column study was conducted for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D), a widely used herbicide from synthetically prepared wastewater using surfactant modified silica gel waste (SMSGW) as an adsorbing media. The adsorbing media was prepared by treating silica gel waste (SGW) with cationic surfactant. The removal was due to adsolubilization of 2,4-D molecules within the admicelles formed on the surface of SGW. The column having 2.5 cm diameter, with different bed heights such as 20, 30 and 40 cm were used in the study. The different column design parameters like depth of exchange zone, time required for exchange zone to move its own height, adsorption rate constant, adsorption capacity constant were calculated using BDST model. The SMSGW was found to be a very efficient media for the removal of 2,4-D from wastewater. Column design parameters were modeled for different field conditions to predict the duration of column run for practical application.

Impacts of backwashing on granular activated carbon filters for advanced wastewater treatment.

PubMed

Frank, Joshua; Ruhl, Aki Sebastian; Jekel, Martin

2015-12-15

The use of granular activated carbon (GAC) in fixed bed filters is a promising option for the removal of organic micropollutants (OMP) from wastewater treatment plant effluents. Frequent backwashing of the filter bed is inevitable, but its effect on potential filter stratification is not well understood yet and thus has been evaluated in the present study for two commercial GAC products. Backwashing of GAC filters was simulated with 10 or 100 filter bed expansions of 20 or 100% at backwash velocities of 12 and 40 m/h, respectively. Five vertical fractions were extracted and revealed a vertical stratification according to grain sizes and material densities. Sieve analyses indicated increasing grain sizes towards the bottom for one GAC while grain sizes of the other GAC were more homogeneously distributed throughout the filter bed. The apparent densities of the top sections were significantly lower than that of the bottom sections of both products. Comparative long term fixed bed adsorption experiments with the top and bottom sections of the stratified GAC showed remarkable differences in breakthrough curves of dissolved organic carbon, UV light absorption at 254 nm wavelength (UVA254) and OMP. GAC from the upper section showed constantly better removal efficiencies than GAC from the bottom section, especially for weakly adsorbing OMP such as sulfamethoxazole. Furthermore correlations between UVA254 reductions and OMP removals were found. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermal and chemical remediation of mixed waste

DOEpatents

Nelson, P.A.; Swift, W.M.

1994-08-09

A process and system for treating organic waste materials without venting gaseous emissions to the atmosphere. A fluidized bed including lime particles is operated at a temperature of at least 500 C by blowing gas having 20%/70% oxygen upwardly through the bed particles at a rate sufficient to fluidize same. A toxic organic waste material is fed into the fluidized bed where the organic waste material reacts with the lime forming CaCO[sub 3]. The off gases are filtered and cooled to condense water which is separated. A portion of the calcium carbonate formed during operation of the fluidized bed is replaced with lime particles. The off gases from the fluidized bed after drying are recirculated until the toxic organic waste material in the bed is destroyed. 3 figs.

Thermal and chemical remediation of mixed waste

DOEpatents

Nelson, Paul A.; Swift, William M.

1994-01-01

A process and system for treating organic waste materials without venting gaseous emissions to the atmosphere. A fluidized bed including lime particles is operated at a temperature of at least 500.degree. C. by blowing gas having 20%/70% oxygen upwardly through the bed particles at a rate sufficient to fluidize same. A toxic organic waste material is fed into the fluidized bed where the organic waste material reacts with the lime forming CaCO.sub.3. The off gases are filtered and cooled to condense water which is separated. A portion of the calcium carbonate formed during operation of the fluidized bed is replaced with lime particles. The off gases from the fluidized bed after drying are recirculated until the toxic organic waste material in the bed is destroyed.

Tolerance or avoidance: drought frequency determines the response of an N2 -fixing tree.

PubMed

Minucci, Jeffrey M; Miniat, Chelcy Ford; Teskey, Robert O; Wurzburger, Nina

2017-07-01

Climate change is increasing drought frequency, which may affect symbiotic N 2 fixation (SNF), a process that facilitates ecosystem recovery from disturbance. Here, we assessed the effect of drought frequency on the ecophysiology and SNF rate of a common N 2 -fixing tree in eastern US forests. We grew Robinia pseudoacacia seedlings under the same mean soil moisture, but with different drought frequency caused by wet-dry cycles of varying periodicity. We found no effect of drought frequency on final biomass or mean SNF rate. However, seedlings responded differently to wet and dry phases depending on drought frequency. Under low-frequency droughts, plants fixed carbon (C) and nitrogen (N) at similar rates during wet and dry phases. Conversely, under high-frequency droughts, plants fixed C and N at low rates during dry phases and at high rates during wet phases. Our findings suggest that R. pseudoacacia growth is resistant to increased drought frequency because it employs two strategies - drought tolerance or drought avoidance, followed by compensation. SNF may play a role in both by supplying N to leaf tissues for acclimation and by facilitating compensatory growth following drought. Our findings point to SNF as a mechanism for plants and ecosystems to cope with drought. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

Wastewater treatment with submerged fixed bed biofilm reactor systems--design rules, operating experiences and ongoing developments.

PubMed

Schlegel, S; Koeser, H

2007-01-01

Wastewater treatment systems using bio-films that grow attached to a support media are an alternative to the widely used suspended growth activated sludge process. Different fixed growth biofilm reactors are commercially used for the treatment of municipal as well as industrial wastewater. In this paper a fairly new fixed growth biofilm system, the submerged fixed bed biofilm reactor (SFBBR), is discussed. SFBBRs are based on aerated submerged fixed open structured plastic media for the support of the biofilm. They are generally operated without sludge recirculation in order to avoid clogging of the support media and problems with the control of the biofilm. Reactor and process design considerations for these reactors are reviewed. Measures to ensure the development and maintenance of an active biofilm are examined. SFBBRs have been applied successfully to small wastewater treatment plants where complete nitrification but no high degree of denitrification is necessary. For the pre-treatment of industrial wastewater the use of SFBBRs is advantageous, especially in cases of wastewater with high organic loading or high content of compounds with low biodegradability. Performance data from exemplary commercial plants are given. Ongoing research and development efforts aim at achieving a high simultaneous total nitrogen (TN) removal of aerated SFBBRs and at improving the efficiency of TN removal in anoxic SFBBRs.

Updraft gasification of salmon processing waste.

PubMed

Rowland, Sarah; Bower, Cynthia K; Patil, Krushna N; DeWitt, Christina A Mireles

2009-10-01

The purpose of this study was to judge the feasibility of gasification for the disposal of waste streams generated through salmon harvesting. Gasification is the process of converting carbonaceous materials into combustible "syngas" in a high temperature (above 700 degrees C), oxygen deficient environment. Syngas can be combusted to generate power, which recycles energy from waste products. At 66% to 79% moisture, raw salmon waste streams are too wet to undergo pyrolysis and combustion. Ground raw or de-oiled salmon whole fish, heads, viscera, or frames were therefore "dried" by mixing with wood pellets to a final moisture content of 20%. Ground whole salmon with moisture reduced to 12% moisture was gasified without a drying agent. Gasification tests were performed in a small-scale, fixed-bed, updraft gasifer. After an initial start-up period, the gasifier was loaded with 1.5 kg of biomass. Temperature was recorded at 6 points in the gasifier. Syngas was collected during the short steady-state period during each gasifier run and analyzed. Percentages of each type of gas in the syngas were used to calculate syngas heating value. High heating value (HHV) ranged from 1.45 to 1.98 MJ/kg. Bomb calorimetry determined maximum heating value for the salmon by-products. Comparing heating values shows the efficiency of gasification. Cold gas efficiencies of 13.6% to 26% were obtained from the various samples gasified. Though research of gasification as a means of salmon waste disposal and energy production is ongoing, it can be concluded that pre-dried salmon or relatively low moisture content mixtures of waste with wood are gasifiable.

Seabird nutrient subsidies benefit non-nitrogen fixing trees and alter species composition in South American coastal dry forests.

PubMed

Havik, Gilles; Catenazzi, Alessandro; Holmgren, Milena

2014-01-01

Marine-derived nutrients can increase primary productivity and change species composition of terrestrial plant communities in coastal and riverine ecosystems. We hypothesized that sea nutrient subsidies have a positive effect on nitrogen assimilation and seedling survival of non-nitrogen fixing species, increasing the relative abundance of non-nitrogen fixing species close to seashore. Moreover, we proposed that herbivores can alter the effects of nutrient supplementation by preferentially feeding on high nutrient plants. We studied the effects of nutrient fertilization by seabird guano on tree recruitment and how these effects can be modulated by herbivorous lizards in the coastal dry forests of northwestern Peru. We combined field studies, experiments and stable isotope analysis to study the response of the two most common tree species in these forests, the nitrogen-fixing Prosopis pallida and the non-nitrogen-fixing Capparis scabrida. We did not find differences in herbivore pressure along the sea-inland gradient. We found that the non-nitrogen fixing C. scabrida assimilates marine-derived nitrogen and is more abundant than P. pallida closer to guano-rich soil. We conclude that the input of marine-derived nitrogen through guano deposited by seabirds feeding in the Pacific Ocean affects the two dominant tree species of the coastal dry forests of northern Peru in contrasting ways. The non-nitrogen fixing species, C. scabrida may benefit from sea nutrient subsidies by incorporating guano-derived nitrogen into its foliar tissues, whereas P. pallida, capable of atmospheric fixation, does not.

Seabird Nutrient Subsidies Benefit Non-Nitrogen Fixing Trees and Alter Species Composition in South American Coastal Dry Forests

PubMed Central

Havik, Gilles; Catenazzi, Alessandro; Holmgren, Milena

2014-01-01

Marine-derived nutrients can increase primary productivity and change species composition of terrestrial plant communities in coastal and riverine ecosystems. We hypothesized that sea nutrient subsidies have a positive effect on nitrogen assimilation and seedling survival of non-nitrogen fixing species, increasing the relative abundance of non-nitrogen fixing species close to seashore. Moreover, we proposed that herbivores can alter the effects of nutrient supplementation by preferentially feeding on high nutrient plants. We studied the effects of nutrient fertilization by seabird guano on tree recruitment and how these effects can be modulated by herbivorous lizards in the coastal dry forests of northwestern Peru. We combined field studies, experiments and stable isotope analysis to study the response of the two most common tree species in these forests, the nitrogen-fixing Prosopis pallida and the non-nitrogen-fixing Capparis scabrida. We did not find differences in herbivore pressure along the sea-inland gradient. We found that the non-nitrogen fixing C. scabrida assimilates marine-derived nitrogen and is more abundant than P. pallida closer to guano-rich soil. We conclude that the input of marine-derived nitrogen through guano deposited by seabirds feeding in the Pacific Ocean affects the two dominant tree species of the coastal dry forests of northern Peru in contrasting ways. The non-nitrogen fixing species, C. scabrida may benefit from sea nutrient subsidies by incorporating guano-derived nitrogen into its foliar tissues, whereas P. pallida, capable of atmospheric fixation, does not. PMID:24466065

An ethanol-based fixation method for anatomical and micro-morphological characterization of leaves of various tree species.

PubMed

Chieco, C; Rotondi, A; Morrone, L; Rapparini, F; Baraldi, R

2013-02-01

The use of formalin constitutes serious health hazards for laboratory workers. We investigated the suitability and performance of the ethanol-based fixative, FineFIX, as a substitute for formalin for anatomical and cellular structure investigations of leaves by light microscopy and for leaf surface and ultrastructural analysis by scanning electron microscopy (SEM). We compared the anatomical features of leaf materials prepared using conventional formalin fixation with the FineFIX. Leaves were collected from ornamental tree species commonly used in urban areas. FineFIX was also compared with glutaraldehyde fixation and air drying normally used for scanning electron microscopy to develop a new method for evaluating leaf morphology and microstructure in three ornamental tree species. The cytological features of the samples processed for histological analysis were well preserved by both fixatives as demonstrated by the absence of nuclear swelling or shrinkage, cell wall detachment or tissue flaking, and good presentation of cytoplasmic vacuolization. In addition, good preservation of surface details and the absence of shrinkage artefacts confirmed the efficacy of FineFIX fixation for SEM analysis. Cuticular wax was preserved only in air dried samples. Samples treated with chemical substances during the fixation and dehydration phases showed various alterations of the wax structures. In some air dried samples a loss of turgidity of the cells was observed that caused general wrinkling of the epidermal surfaces. Commercial FineFIX is an adequate substitute for formalin in histology and it can be applied successfully also for SEM investigation, while reducing the health risks of glutaraldehyde or other toxic fixatives. To investigate the potential for plants to absorb and capture particulates in air, which requires preservation of the natural morphology of trichomes and epicuticular waxes, a combination of FineFIX fixation and air drying is recommended.

Mathematical Modelling of Drying Kinetics of Wheat in Electron Fired Fluidized Bed Drying System

NASA Astrophysics Data System (ADS)

Deomore, Dayanand N.; Yarasu, Ravindra B.

2018-02-01

The conventional method of electrical heating is replaced by electron firing system. The drying kinetics of wheat is studied using electron fired fluidized bed dryer. The results are simulated by using ANSYS. It was observed that the graphs are in agreement with each other. Therefore, the new proposed electronic firing system can be employed instead of electrical firing. It was observed that the drop in Relative Humidity in case of Electrical heating is 68.75% for temp reaching up to 70° C in 67 sec for pressure drop of 13 psi while for the electronic Firing system it is 67.6 % temp reaches to 70° C in 70 sec for pressure drop of 12.67 psi. As the results are in agreement with each other it was concluded that for the grains like wheat which has low initial moisture content both systems can be used.

Upflow fixed bed bioelectrochemical reactor for wastewater treatment applications.

PubMed

González-Gutiérrez, Linda; Frontana, Carlos; Martínez, Eduardo

2015-01-01

A cylindrical Upflow Fixed Bed Reactor (UFB-BER) with granular activated carbon, steel mesh electrodes and anaerobic microorganisms, was constructed for analyzing how hydrodynamic parameters affect the reactions involved during wastewater treatment processes for azo dye degradation. Dye removal percentage was not compromised by decreasing HRTm (99-90% upon changing HRTm from 4 to 1h in single pass mode). Using the residence time distribution method for hydrodynamic characterization, it was found that a higher dispersion in the reactor occurs for HRTm=1h, than for HRTm=4h. A kinetic analysis suggests that this dispersion effect could be associated to a higher specific reaction rate dependent on the azo dye concentration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Adsorption equilibrium and kinetics of Immunoglobulin G on a mixed-mode adsorbent in batch and packed bed configuration.

PubMed

Gomes, Pedro Ferreira; Loureiro, José Miguel; Rodrigues, Alírio E

2017-11-17

It is commonly accepted that efficient protein separation and purification to the desired level of purity is one bottleneck in pharmaceutical industries. MabDirect MM is a new type of mixed mode adsorbent, especially designed to operate in expanded bed adsorption (EBA) mode. In this study, equilibrium and kinetics experiments were carried out for the adsorption of Human Immunoglobulin G (hIgG) protein on this new adsorbent. The effects of ionic strength and pH are assessed. Langmuir isotherms parameters are obtained along with the estimation of the effective pore diffusion coefficient (D pe ) by fitting the batch adsorption kinetics experiments with the pore diffusion model. The maximum adsorption of the IgG protein on the MabDirect MM adsorbent, 149.7±7.1mg·g dry -1 , was observed from a pH 5.0 buffer solution without salt addition. Adding salt to the buffer solution, and/or increasing pH, decreases the adsorption capacity which is 4.7±0.4mg·g dry -1 for pH 7.0 with 0.4M NaCl in solution. Regarding the D pe estimation, a value of 15.4×10 -6 cm 2 ·min -1 was obtained for a pH 5.0 solution without salt. Increasing the salt concentration and/or the pH value will decrease the effective pore diffusion, the lowest D pe (0.16×10 -6 cm 2 ·min -1 ) value being observed for an IgG solution at pH 7.0 with 0.4M NaCl. Fixed bed experiments were conducted with the purpose to validate the equilibrium and kinetic parameters obtained in batch. For a feed concentration of 0.5 g·L -1 of IgG in pH 5.0 buffer solution with 0.4M NaCl, a dynamic binding capacity at 10% of breakthrough of 5.3mg·g wet -1 (15.4mg IgG ·mL resin -1 ) was obtained, representing 62% of the saturation capacity. As far as the authors know, this study is the first one concerning the adsorption of hIgG on this type of mixed mode chromatography adsorbent. Copyright © 2017 Elsevier B.V. All rights reserved.

Sedimentology and sequence stratigraphy of the Lower Jurassic Kayenta Formation, Colorado Plateau, United States

NASA Astrophysics Data System (ADS)

Sanabria, Diego Ignacio

2001-07-01

Detailed outcrop analysis of the Lower Jurassic Kayenta Formation provides the basis for the formulation of a new sequence stratigraphic model for arid to semi-arid continental deposits and the generation of a comprehensive set of sedimentologic criteria for the recognition of ephemeral stream deposits. Criteria for the recognition of ephemeral deposits in the ancient record were divided into three categories according to the scale of the feature being considered. The first category takes into account sedimentary structures commonly found in the record of ephemeral stream deposits including hyperconcentrated and debris flow deposits, planar parallel bedding, sigmoidal cross-bedding, hummocky cross-bedding, climbing ripple lamination, scour-and-fill structures, convolute bedding, overturned cross-bedding, ball-and-pillow structures, pocket structures, pillars, mud curls, flaser lamination, algal lamination, termite nests, and vertebrate tracks. The second category is concerned with the mesoscale facies architecture of ephemeral stream deposits and includes waning flow successions, bedform climb, downstream accretion, terminal wadi splays, and channel-fill successions indicating catastrophic flooding. At the large-scale facies architecture level, the third category, ephemeral stream deposits are commonly arranged in depositional units characterized by a downstream decrease in grain size and scale of sedimentary structures resulting from deposition in terminal fan systems. Outcrops of the Kayenta Formation and its transition to the Navajo Sandstone along the Vermilion and Echo Cliffs of Northern Arizona indicate that wet/dry climatic cyclicity exerted a major control on regional facies architecture. Two scales of wet/dry climatic cyclicity can be recognized in northern Arizona. Three sequence sets composed of rocks accumulated under predominantly dry or wet conditions are the expression of long-term climatic cyclicity. Short-term climatic cyclicity, on the other hand, is represented by high-frequency sequences composed of eolian or ephemeral fluvial deposits overlain by perennial fluvial sediments. Increased evapotranspiration rates, depressed water tables, and accumulation of eolian or ephemeral fluvial deposits characterize the dry portion of these cycles. The wet part of the cycles is marked by an increase in precipitation and the establishment of perennial fluvial systems and lacustrine basins. This depositional model constitutes a valuable tool for correlation of similar deposits in the subsurface.

Thermal Cracking of Tars in a Continuously Fed Reactor with Steam

DTIC Science & Technology

2011-05-01

Fluidized Bed using biomass 8 Tars  Mixture of organic components present in gasification product gas with high molecular weight hydrocarbons [MW...Disable sulfur removal systems FoulingPlugging [Ref. 3: Biomass Gasification – Tar and Particles in Product Gases Sampling and Analysis”, European...P., and Nussbaumer T., “Gas Cleaning Requirements for Internal Combustion Engine Applications of Fixed Bed Biomass Gasification ”, Biomass and

Determination of Electrical Resistivity of Dry Coke Beds

NASA Astrophysics Data System (ADS)

Eidem, P. A.; Tangstad, M.; Bakken, J. A.

2008-02-01

The electrical resistivity of the coke bed is of great importance when producing FeMn, SiMn, and FeCr in a submerged arc furnace. In these processes, a coke bed is situated below and around the electrode tip and consists of metallurgical coke, slag, gas, and metal droplets. Since the basic mechanisms determining the electrical resistivity of a coke bed is not yet fully understood, this investigation is focused on the resistivity of dry coke beds consisting of different carbonaceous materials, i.e., coke beds containing no slag or metal. A method that reliably compares the electrical bulk resistivity of different metallurgical cokes at 1500 °C to 1600 °C is developed. The apparatus is dimensioned for industrial sized materials, and the electrical resistivity of anthracite, charcoal, petroleum coke, and metallurgical coke has been measured. The resistivity at high temperatures of the Magnitogorsk coke, which has the highest resistivity of the metallurgical cokes investigated, is twice the resistivity of the Corus coke, which has the lowest electrical resistivity. Zdzieszowice and SSAB coke sort in between with decreasing resistivities in the respective order. The electrical resistivity of anthracite, charcoal, and petroleum coke is generally higher than the resistivity of the metallurgical cokes, ranging from about two to about eight times the resistivity of the Corus coke at 1450 °C. The general trend is that the bulk resistivity of carbon materials decreases with increasing temperature and increasing particle size.

Resistance to airflow through bedding materials used in infancy.

PubMed Central

Hatch, D J; Helms, P; Matthew, D J; Skinner, D

1982-01-01

Various bedding materials used in infancy, including duvets (or continental quilts), were tested for airflow using the British Standards Institution tests for pillows or fabrics. Resistance was also measured when the items were placed on a dummy infant face. Measurements were made on washed and unwashed garments, which were tested both dry and wet. Results suggest that all the bedding materials tested are safe for use even in the newborn period. The duvets produced slightly lower resistance to breathing than conventional blankets and sheets. In view of the wide variety of infant bedding fabrics it seems desirable for standard airflow performance requirements to be introduced. PMID:7092309

New approach for dry formulation techniques for rhizobacteria

NASA Astrophysics Data System (ADS)

Elchin, A. A.; Mashinistova, A. V.; Gorbunova, N. V.; Muratov, V. S.; Kydralieva, K. A.; Jorobekova, Sh. J.

2009-04-01

Two beneficial Pseudomonas isolates selected from rhizosphere of abundant weed - couch-grass Elytrigia repens L. Nevski have been found to have biocontrol activity. An adequate biocontrol effect requires high yield and long stability of the bacterial preparation [1], which could be achieved by an effective and stable formulation. This study was aimed to test various approaches to dry formulation techniques for Pseudomonas- based preparations. To reach this goal, two drying formulation techniques have been tested: the first one, spray drying and the second, low-temperature contact-convective drying in fluidized bed. The optimal temperature parameters for each technique were estimated. Main merits of the selected approach to dry technique are high yield, moderate specific energy expenditures per 1 kg of evaporated moisture, minimal time of contact of the drying product with drying agent. The technological process for dry formulation included the following stages: the obtaining of cell liquids, the low-temperature concentrating and the subsequent drying of a concentrate. The preliminary technological stages consist in cultivation of the rhizobacteria cultures and concentrating the cell liquids. The following requirements for cultivation regime in laboratory conditions were proposed: optimal temperatures are 26-28°С in 3 days, concentration of viable cells in cell liquid makes 1010-1011 cell/g of absolutely dry substance (ADS). For concentrating the cell liquids the method of a vacuum evaporation, which preserves both rhizobacteria cells and the secondary metabolites of cell liquid, has been used. The process of concentrating was conducted at the minimum possible temperature, i.e. not above 30-33°С. In this case the concentration of viable cells has decreased up to 109-1010 cell/g of ADS. For spray drying the laboratory up-dated drier BUCHI 190, intended for the drying of thermolabile products, was used. The temperatures of an in- and outcoming air did not exceed 50°С and 38°С, respectively. To enrich of dry product yield, 20% of sodium humate [2] was used as filling agent. As a result, concentration of viable cells in yield makes 105-106 cell/g of ADS. Low-temperature contact-convective drying in fluidized bed with use of preliminarily dried heat-carrier was evaluated at 25-30°С. Granules of humic acids (d 3 mm) served as inert carrying agent. So, the concentration of viable cells in dry product makes 108-109 cell/g of ADS. The results presented demonstrated that fluidized bed drying technique applied on rhizobacteria-based BCA had higher beneficial effect in terms of high yield as compared to spray drying. Acknowledgement. This research was supported by the grant of ISTC KR-993.2. 1. Levenfors, J.R., et al. Biological control of snow mould (Microdochium nivale) in winter cereals by Pseudomonas brassicacearum MA250. Biocontrol 2007. 2. Orlov, D.S. (1990) Soil Humic Acids and General Theory of Humification, MSU Publisher, Moscow

A Preliminary Study on Rock Bed Heat Storage from Biomass Combustion for Rice Drying

NASA Astrophysics Data System (ADS)

Nelwan, L. O.; Wulandani, D.; Subrata, I. D. M.

2018-05-01

One of the main constraints of biomass fuel utilization in a small scale rice drying system is the operating difficulties related to the adjustment of combustion/feeding rate. Use of thermal storage may reduce the problem since combustion operation can be accomplished in a much shorter time and then the use of heat can be regulated by simply adjusting the air flow. An integrated biomass furnace-rock bed thermal storage with a storage volume of 540 L was designed and tested. There were four experiments conducted in this study. Charging was performed within 1-2 hours with a combustion rate of 11.5-15.5 kg/h. In discharging process, the mixing of air passing through the rock bed and ambient air were regulated by valves. Without adjusting the valve during the discharging process, air temperature increased up to 80°C, which is not suitable for rice batch drying process. Charging with sufficiently high combustion rate (14 kg/h) within 1 hour continued by adjusting the valve during discharging process below 60°C increased the discharge-charge time ratio (DCTR) up to 5.33 at average air temperature of 49°C and ambient temperature of 33°C.The efficiency of heat discharging was ranged from 34.5 to 45.8%. From the simulation, as much as 156.8-268.8 kg of rice was able to be dried by the discharging conditions.

Bacterial flora of commonly used soaps in three hospitals in Nigeria.

PubMed

Afolabi, B A; Oduyebo, O O; Ogunsola, F T

2007-10-01

To obtain general information on soap use and soap bacterial flora, and to assess the risk of transmission of organisms from contaminated soap to patients. Descriptive study. Three hospitals in an urban area of Lagos, Nigeria. A teaching (761 bed) hospital, a general hospital (a 51 bed secondary healthcare facility) and a private hospital (a 30 bed private community with a surgical specialty). Bar soaps were much more commonly used than liquid soaps. Out of the thirty six bar soaps and their receptacles studied, 19 (52.8%) were found wet, nine (25%) dry, five (13.9%) very dry, and three (8.3%) in a pool of water. A total of 39% soaps and 75% of receptacles were contaminated. Thirty three percent of the dry soaps and 68.4% of the wet soaps were contaminated. None of the very dry soaps and all in a pool of water were contaminated. The bacteria isolated from soaps included Pseudomonas aeruginosa (89.5%) and Klebsiella pneumoniae (10.5%), while Pseudomonas aeruginosa (70.6%), Klebsiella pneumoniae (14.7%), Staphylococcus aureus (11.8%) and Serratia marcescens (2.9%) were isolated from the receptacles. The antibiogram showed that the Pseudomonas aeruginosa isolated from the soaps and their containers (sinks) were distinct from those obtained from colonised or infected wounds. The soap contamination rates correlated with the conditions in which the soaps were kept. The type of soap containers in particular, played a vital role in keeping the soap dry or wet. In all the hospitals studied, the policies on soap use, if any, were not in agreement with the recommended guidelines. The healthcare workers need to be re-educated on these guidelines.

Effect of Fumigation on Rotylenchulus reniformis Population Density Through Subsurface Drip Irrigation Located Every Other Furrow.

PubMed

Wheeler, T A; Porter, D O; Archer, D; Mullinix, B G

2008-09-01

Plots naturally infested with Rotylenchulus reniformis were sampled in the spring of 2006 and 2007 at depths of 15 and 30 cm in the bed, furrow over the drip tape, and "dry" furrow, and at approximately 40 to 45 cm depth in the bed and dry furrow. Then, 1,3-dichloropropene (Telone EC) was injected into the subsurface drip irrigation at 46 kg a.i./ha, and 3 to 4 weeks later the plots were resampled and assayed for nematodes. The transformed values for nematode population density (IvLRr) before fumigation were higher at 30 and 40 cm depths than at a 15 cm depth. IvLRr before fumigation was higher in the soil over the drip lines than in the bed or dry furrow and was higher in the bed than the dry furrow. IvLRr was higher in the plots to be fumigated than the plots that were not to be fumigated for all depths and locations except at a 15 cm depth over the drip lines, where the values were similar. However, after fumigation, IvLRr was lower over the drip lines at a 30 cm depth in plots that were fumigated compared to samples in a similar location and depth that were not fumigated. There were no other location/depth combinations where the fumigation reduced IvLRr below that in the nonfumigated plots. Yield in 2006, which was a very hot and dry year, was predicted adequately (R(2) = 0.67) by a linear model based on the preplant population density of R. reniformis, with a very steep slope (-2.8 kg lint/ha per R. reniformis/100 cm(3) soil). However, no relationship between nematode density and yield was seen in 2007, which had cooler weather for most of the season. Yield was not significantly improved by fumigation through the drip irrigation system in either year compared to plots treated only with aldicarb (0.84 kg a.i./ha), indicating that the level of control with fumigation did not kill enough R. reniformis to be successful.

Scaling of Sediment Dynamics in a Reach-Scale Laboratory Model of a Sand-Bed Stream with Riparian Vegetation

NASA Astrophysics Data System (ADS)

Gorrick, S.; Rodriguez, J. F.

2011-12-01

A movable bed physical model was designed in a laboratory flume to simulate both bed and suspended load transport in a mildly sinuous sand-bed stream. Model simulations investigated the impact of different vegetation arrangements along the outer bank to evaluate rehabilitation options. Preserving similitude in the 1:16 laboratory model was very important. In this presentation the scaling approach, as well as the successes and challenges of the strategy are outlined. Firstly a near-bankfull flow event was chosen for laboratory simulation. In nature, bankfull events at the field site deposit new in-channel features but cause only small amounts of bank erosion. Thus the fixed banks in the model were not a drastic simplification. Next, and as in other studies, the flow velocity and turbulence measurements were collected in separate fixed bed experiments. The scaling of flow in these experiments was simply maintained by matching the Froude number and roughness levels. The subsequent movable bed experiments were then conducted under similar hydrodynamic conditions. In nature, the sand-bed stream is fairly typical; in high flows most sediment transport occurs in suspension and migrating dunes cover the bed. To achieve similar dynamics in the model equivalent values of the dimensionless bed shear stress and the particle Reynolds number were important. Close values of the two dimensionless numbers were achieved with lightweight sediments (R=0.3) including coal and apricot pips with a particle size distribution similar to that of the field site. Overall the moveable bed experiments were able to replicate the dominant sediment dynamics present in the stream during a bankfull flow and yielded relevant information for the analysis of the effects of riparian vegetation. There was a potential conflict in the strategy, in that grain roughness was exaggerated with respect to nature. The advantage of this strategy is that although grain roughness is exaggerated, the similarity of bedforms and resulting drag can return similar levels of roughness to those in the field site.

DNA-based methodologies for the quantification of live and dead cells in formulated biocontrol products based on Pantoea agglomerans CPA-2.

PubMed

Soto-Muñoz, Lourdes; Torres, Rosario; Usall, Josep; Viñas, Inmaculada; Solsona, Cristina; Teixidó, Neus

2015-10-01

Pantoea agglomerans strain CPA-2 is an effective biocontrol agent (BCA) against the major postharvest pathogens present on pome and citrus fruits. Dehydration, such as freeze-drying, spray-drying and fluidized bed drying is one of the best ways to formulate BCAs. In this work, the survival of CPA-2 cells after formulation was determined by dilution plating and molecular methods as qPCR alone and combined with a sample pretreatment with a propidium monoazide dye (PMA-qPCR) and they were used to calculate treatment concentrations in efficacy trials on postharvest oranges. Furthermore, no significant differences in CPA-2 survival were observed as determined by dilution plating and PMA-qPCR after both the freeze drying and fluidized bed drying processes; however, an interesting significant difference was observed in the spray dried product comparing all quantitative methods. A difference of 0.48 and 2.17 log10 CFU or cells g/dw was observed among PMA-qPCR with qPCR and dilution plating, respectively. According to our study, dilution plating was shown to be an unreliable tool for monitoring the survival of CPA-2 after spray drying. In contrast, the combination of PMA and qPCR enabled a quick and unequivocal methodology to enumerate viable and VBNC CPA-2 cells under stress-dried conditions. Efficacy trials showed that, after 3 days, spray drying formulation rehydrated with 10% non-fat skimmed milk (NFSM) was as effective as fresh cells to control Penicillium digitatum in oranges. Copyright © 2015 Elsevier B.V. All rights reserved.

40 CFR 60.155 - Reporting.

Code of Federal Regulations, 2012 CFR

2012-07-01

.... (a) The owner or operator of any multiple hearth, fluidized bed, or electric sludge incinerator... kg/Mg (0.75 lb/ton) dry sludge input or less during the most recent performance test, a scrubber... particulate matter emission rate of greater than 0.38 kg/Mg (0.75 lb/ton) dry sludge input during the most...

40 CFR 60.155 - Reporting.

Code of Federal Regulations, 2013 CFR

2013-07-01

.... (a) The owner or operator of any multiple hearth, fluidized bed, or electric sludge incinerator... kg/Mg (0.75 lb/ton) dry sludge input or less during the most recent performance test, a scrubber... particulate matter emission rate of greater than 0.38 kg/Mg (0.75 lb/ton) dry sludge input during the most...

40 CFR 60.155 - Reporting.

Code of Federal Regulations, 2014 CFR

2014-07-01

.... (a) The owner or operator of any multiple hearth, fluidized bed, or electric sludge incinerator... kg/Mg (0.75 lb/ton) dry sludge input or less during the most recent performance test, a scrubber... particulate matter emission rate of greater than 0.38 kg/Mg (0.75 lb/ton) dry sludge input during the most...

40 CFR 60.155 - Reporting.

Code of Federal Regulations, 2011 CFR

2011-07-01

.... (a) The owner or operator of any multiple hearth, fluidized bed, or electric sludge incinerator... kg/Mg (0.75 lb/ton) dry sludge input or less during the most recent performance test, a scrubber... particulate matter emission rate of greater than 0.38 kg/Mg (0.75 lb/ton) dry sludge input during the most...

Fully coupled approach to modeling shallow water flow, sediment transport, and bed evolution in rivers

NASA Astrophysics Data System (ADS)

Li, Shuangcai; Duffy, Christopher J.

2011-03-01

Our ability to predict complex environmental fluid flow and transport hinges on accurate and efficient simulations of multiple physical phenomenon operating simultaneously over a wide range of spatial and temporal scales, including overbank floods, coastal storm surge events, drying and wetting bed conditions, and simultaneous bed form evolution. This research implements a fully coupled strategy for solving shallow water hydrodynamics, sediment transport, and morphological bed evolution in rivers and floodplains (PIHM_Hydro) and applies the model to field and laboratory experiments that cover a wide range of spatial and temporal scales. The model uses a standard upwind finite volume method and Roe's approximate Riemann solver for unstructured grids. A multidimensional linear reconstruction and slope limiter are implemented, achieving second-order spatial accuracy. Model efficiency and stability are treated using an explicit-implicit method for temporal discretization with operator splitting. Laboratory-and field-scale experiments were compiled where coupled processes across a range of scales were observed and where higher-order spatial and temporal accuracy might be needed for accurate and efficient solutions. These experiments demonstrate the ability of the fully coupled strategy in capturing dynamics of field-scale flood waves and small-scale drying-wetting processes.

Improved lignin pyrolysis for phenolics production in a bubbling bed reactor--Effect of bed materials.

PubMed

Li, Dongbing; Briens, Cedric; Berruti, Franco

2015-01-01

Lignin pyrolysis was studied in a bubbling fluidized bed reactor equipped with a fractional condensation train, using nitrogen as the fluidization gas. The effect of different bed materials (silica sand, lignin char, activated lignin char, birch bark char, and foamed glass beads) on bio-oil yield and quality was investigated for a pyrolysis temperature of 550 °C. Results how that a bed of activated lignin char is preferable to the commonly used silica sand: pyrolysis of Kraft lignin with a bed of activated lignin char not only provides a pure char product, but also a higher dry bio-oil yield (with a relative increase of 43%), lower pyrolytic water production, and better bio-oil quality. The bio-oil obtained from Kraft lignin pyrolysis with a bed of activated lignin char has a lower average molecular weight, less tar, more phenolics, and less acidity than when sand is used as bed material. Copyright © 2015 Elsevier Ltd. All rights reserved.

Numerical investigation of flow and heat transfer in a novel configuration multi-tubular fixed bed reactor for propylene to acrolein process

NASA Astrophysics Data System (ADS)

Jiang, Bin; Hao, Li; Zhang, Luhong; Sun, Yongli; Xiao, Xiaoming

2015-01-01

In the present contribution, a numerical study of fluid flow and heat transfer performance in a pilot-scale multi-tubular fixed bed reactor for propylene to acrolein oxidation reaction is presented using computational fluid dynamics (CFD) method. Firstly, a two-dimensional CFD model is developed to simulate flow behaviors, catalytic oxidation reaction, heat and mass transfer adopting porous medium model on tube side to achieve the temperature distribution and investigate the effect of operation parameters on hot spot temperature. Secondly, based on the conclusions of tube-side, a novel configuration multi-tubular fixed-bed reactor comprising 790 tubes design with disk-and-doughnut baffles is proposed by comparing with segmental baffles reactor and their performance of fluid flow and heat transfer is analyzed to ensure the uniformity condition using molten salt as heat carrier medium on shell-side by three-dimensional CFD method. The results reveal that comprehensive performance of the reactor with disk-and-doughnut baffles is better than that of with segmental baffles. Finally, the effects of operating conditions to control the hot spots are investigated. The results show that the flow velocity range about 0.65 m/s is applicable and the co-current cooling system flow direction is better than counter-current flow to control the hottest temperature.

Application of response surface methodology and semi-mechanistic model to optimize fluoride removal using crushed concrete in a fixed-bed column.

PubMed

Gu, Bon-Wun; Lee, Chang-Gu; Park, Seong-Jik

2018-03-01

The aim of this study was to investigate the removal of fluoride from aqueous solutions by using crushed concrete fines as a filter medium under varying conditions of pH 3-7, flow rate of 0.3-0.7 mL/min, and filter depth of 10-20 cm. The performance of fixed-bed columns was evaluated on the basis of the removal ratio (Re), uptake capacity (qe), degree of sorbent used (DoSU), and sorbent usage rate (SUR) obtained from breakthrough curves (BTCs). Three widely used semi-mechanistic models, that is, Bohart-Adams, Thomas, and Yoon-Nelson models, were applied to simulate the BTCs and to derive the design parameters. The Box-Behnken design of response surface methodology (RSM) was used to elucidate the individual and interactive effects of the three operational parameters on the column performance and to optimize these parameters. The results demonstrated that pH is the most important factor in the performance of fluoride removal by a fixed-bed column. The flow rate had a significant negative influence on Re and DoSU, and the effect of filter depth was observed only in the regression model for DoSU. Statistical analysis indicated that the model attained from the RSM study is suitable for describing the semi-mechanistic model parameters.

Catalyst and process development for synthesis gas conversion to isobutylene. Final report, September 1, 1990--January 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anthony, R.G.; Akgerman, A.

1994-05-06

Previous work on isosynthesis (conversion of synthesis gas to isobutane and isobutylene) was performed at very low conversions or extreme process conditions. The objectives of this research were (1) determine the optimum process conditions for isosynthesis; (2) determine the optimum catalyst preparation method and catalyst composition/properties for isosynthesis; (3) determine the kinetics for the best catalyst; (4) develop reactor models for trickle bed, slurry, and fixed bed reactors; and (5) simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for isosynthesis. More improvement in catalyst activity and selectivity is needed beforemore » isosynthesis can become a commercially feasible (stand-alone) process. Catalysts prepared by the precipitation method show the most promise for future development as compared with those prepared hydrothermally, by calcining zirconyl nitrate, or by a modified sol-gel method. For current catalysts the high temperatures (>673 K) required for activity also cause the production of methane (because of thermodynamics). A catalyst with higher activity at lower temperatures would magnify the unique selectivity of zirconia for isobutylene. Perhaps with a more active catalyst and acidification, oxygenate production could be limited at lower temperatures. Pressures above 50 atm cause an undesirable shift in product distribution toward heavier hydrocarbons. A model was developed that can predict carbon monoxide conversion an product distribution. The rate equation for carbon monoxide conversion contains only a rate constant and an adsorption equilibrium constant. The product distribution was predicted using a simple ratio of the rate of CO conversion. This report is divided into Introduction, Experimental, and Results and Discussion sections.« less

Algal Foams Applied in Fixed-Bed Process for Lead(II) Removal Using Recirculation or One-Pass Modes

PubMed Central

Wang, Shengye; Vincent, Thierry; Faur, Catherine; Guibal, Eric

2017-01-01

The incorporation of brown algae into biopolymer beads or foams for metal sorption has been previously reported. However, the direct use of these biomasses for preparing foams is a new approach. In this study, two kinds of porous foams were prepared by ionotropic gelation using algal biomass (AB, Laminaria digitata) or alginate (as the reference) and applied for Pb(II) sorption. These foams (manufactured as macroporous discs) were packed in filtration holders (simulating fixed-bed column) and the system was operated in either a recirculation or a one-pass mode. Sorption isotherms, uptake kinetics and sorbent reuse were studied in the recirculation mode (analogous to batch system). In the one-pass mode (continuous fixed-bed system), the influence of parameters such as flow rate, feed metal concentration and bed height were investigated on both sorption and desorption. In addition, the effect of Cu(II) on Pb(II) recovery from binary solutions was also studied in terms of both sorption and desorption. Sorption isotherms are well fitted by the Langmuir equation while the pseudo-second order rate equation described well both sorption and desorption kinetic profiles. The study of material regeneration confirms that the reuse of the foams was feasible with a small mass loss, even after 9 cycles. In the one-pass mode, for alginate foams, a slower flow rate led to a smaller saturation volume, while the effect of flow rate was less marked for AB foams. Competitive study suggests that the foams have a preference for Pb(II) over Cu(II) but cannot selectively remove Pb(II) from the binary solution. PMID:29039806

Development and characterization of a carbon-based composite material for reducing patulin levels in apple juice.

PubMed

Huebner, H J; Mayura, K; Pallaroni, L; Ake, C L; Lemke, S L; Herrera, P; Phillips, T D

2000-01-01

Patulin, a heterocyclic lactone produced by various species of Penicillium and Aspergillus fungi, is often detected in apple juices and ciders. Previous research has shown the effectiveness of granular activated carbon for reducing patulin levels in aqueous solutions, apple juices, and ciders. In this study, ultrafine activated carbon was bonded onto granular quartz to produce a composite carbon adsorbent (CCA) with a high carbonaceous surface area, good bed porosity, and increased bulk density. CCA in fixed-bed adsorption columns was evaluated for efficacy in reducing patulin levels from aqueous solutions and apple juice. Columns containing 1.0, 0.5, and 0.25 g of CCA were continuously loaded with a patulin solution (10 microg/ml) and eluted at a flow rate of 1 ml/min. Results indicated that 50% breakthrough capacities for patulin on 1.0-, 0.5-, and 0.25-g CCA columns were 137.5, 38.5, and 19.9 microg, respectively. The effectiveness of CCA to adsorb patulin and prevent toxic effects was confirmed in vitro using adult hydra in culture. Hydra were sensitive to the effects of patulin, with a minimal affective concentration equal to 0.7 microg/ml; CCA adsorption prevented patulin toxicity until 76% breakthrough capacity was achieved. Fixed-bed adsorption with 1.0 g of CCA was also effective in reducing patulin concentrations (20 microg/liter) in a naturally contaminated apple juice, and breakthrough capacities were shown to increase with temperature. Additionally, CCA offered a higher initial breakthrough capacity than pelleted activated carbon when compared in parallel experiments. This study suggests that CCA used in fixed-bed adsorption systems effectively reduced patulin levels in both aqueous solutions and naturally contaminated apple juice; however, the appearance and taste of apple juice may be affected by the treatment process.

Development and characterization of couscous-like product using bulgur flour as by-product.

PubMed

Yuksel, Ayse Nur; Öner, Mehmet Durdu; Bayram, Mustafa

2017-12-01

Couscous is produced traditionally by agglomeration of Triticum durum semolina with water. The aims of this study were: to produce couscous-like product by substitution of semolina with bulgur by-product (undersize bulgur); to find optimum quantity of bulgur flour and processing conditions. In order to determine the optimum processing parameters and recipes; 0, 25 and 50% of bulgur containing couscous-like samples were prepared. The color, yield, sensory properties, total phenol and flavonoid contents, bulk density, protein and ash content, texture properties were determined. Two different types of dryer e.g. packed bed and microwave were used. Optimum parameters were predicted as 50% of bulgur flour for packed bed (60 °C) and microwave (180 W) drying with 50% (w/w) of water according to yields, color (L*, a*, b*) values and sensory properties (color, odor, general appearance). For packed bed drying at 60 °C yields were 54.28 ± 3.78, 47.70 ± 1.73 and 52.57 ± 7.04% for 0, 25 and 50% bulgur flour containing samples, respectively. Lightness (L*) values of couscous-like samples were decreased with increasing the quantity of bulgur flour after both drying processes. Results of sensory analysis revealed that couscous-like bulgur were more preferable for consumers.

Removal of arsenic from drinking water using rice husk

NASA Astrophysics Data System (ADS)

Asif, Zunaira; Chen, Zhi

2017-06-01

Rice husk adsorption column method has proved to be a promising solution for arsenic (As) removal over the other conventional methods. The present work investigates the potential of raw rice husk as an adsorbent for the removal of arsenic [As(V)] from drinking water. Effects of various operating parameters such as diameter of column, bed height, flow rate, initial arsenic feed concentration and particle size were investigated using continuous fixed bed column to check the removal efficiency of arsenic. This method shows maximum removal of As, i.e., 90.7 % under the following conditions: rice husk amount 42.5 g; 7 mL/min flow rate in 5 cm diameter column at the bed height of 28 cm for 15 ppb inlet feed concentration. Removal efficiency was increased from 83.4 to 90.7 % by reducing the particle size from 1.18 mm to 710 µm for 15 ppb concentration. Langmuir and Freundlich isotherm models were employed to discuss the adsorption behavior. The effect of different operating parameters on the column adsorption was determined using breakthrough curves. In the present study, three kinetic models Adam-Bohart, Thomas and Yoon-Nelson were applied to find out the saturated concentration, fixed bed adsorption capacity and time required for 50 % adsorbate breakthrough, respectively. At the end, solidification was done for disposal of rice husk.

A geochemical investigation into the effect of coal rank on the potential environmental effects of CO2 sequestration in deep coal beds

USGS Publications Warehouse

Kolak, Jonathan J.; Burruss, Robert A.

2005-01-01

Coal samples of different rank were extracted in the laboratory with supercritical CO2 to evaluate the potential for mobilizing hydrocarbons during CO2 sequestration or enhanced coal bed methane recovery from deep coal beds. The concentrations of aliphatic hydrocarbons mobilized from the subbituminous C, high-volatile C bituminous, and anthracite coal samples were 41.2, 43.1, and 3.11 ?g g-1 dry coal, respectively. Substantial, but lower, concentrations of polycyclic aromatic hydrocarbons (PAHs) were mobilized from these samples: 2.19, 10.1, and 1.44 ?g g-1 dry coal, respectively. The hydrocarbon distributions within the aliphatic and aromatic fractions obtained from each coal sample also varied with coal rank and reflected changes to the coal matrix associated with increasing degree of coalification. Bitumen present within the coal matrix may affect hydrocarbon partitioning between coal and supercritical CO2. The coal samples continued to yield hydrocarbons during consecutive extractions with supercritical CO2. The amount of hydrocarbons mobilized declined with each successive extraction, and the relative proportion of higher molecular weight hydrocarbons increased during successive extractions. These results demonstrate that the potential for mobilizing hydrocarbons from coal beds, and the effect of coal rank on this process, are important to consider when evaluating coal beds for CO2 storage.

Olivine, dolomite and ceramic filters in one vessel to produce clean gas from biomass.

PubMed

Rapagnà, Sergio; Gallucci, Katia; Foscolo, Pier Ugo

2018-01-01

Heavy organic compounds produced during almond shells gasification in a steam and/or air atmosphere, usually called tar, are drastically reduced in the product gas by using simultaneously in one vessel a ceramic filter placed in the freeboard and a mixture of olivine and dolomite particles in the fluidized bed of the gasifier. The content of tar in the product gas during a reference gasification test with air, in presence of fresh olivine particles only, was 8600mg/Nm 3 of dry gas. By gasifying biomass with steam at the same temperature level of 820°C in a bed of olivine and dolomite (20% by weight), and in the presence of a catalytic ceramic filter inserted in the freeboard of the fluidized bed gasifier, the level of tar was brought down to 57mg/Nm 3 of dry producct gas, with a decrease of more than two orders of magnitude. Copyright © 2017 Elsevier Ltd. All rights reserved.

Shielded fluid stream injector for particle bed reactor

DOEpatents

Notestein, John E.

1993-01-01

A shielded fluid-stream injector assembly is provided for particle bed reactors. The assembly includes a perforated pipe injector disposed across the particle bed region of the reactor and an inverted V-shaped shield placed over the pipe, overlapping it to prevent descending particles from coming into direct contact with the pipe. The pipe and shield are fixedly secured at one end to the reactor wall and slidably secured at the other end to compensate for thermal expansion. An axially extending housing aligned with the pipe and outside the reactor and an in-line reamer are provided for removing deposits from the inside of the pipe. The assembly enables fluid streams to be injected and distributed uniformly into the particle bed with minimized clogging of injector ports. The same design may also be used for extraction of fluid streams from particle bed reactors.

Removal of hexavalent chromium by biosorption process in rotating packed bed.

PubMed

Panda, M; Bhowal, A; Datta, S

2011-10-01

Removal of hexavalent chromium ions from an aqueous solution by crude tamarind (Tamarindus indica) fruit shell was examined in a rotating packed bed contactor by continuously recirculating a given volume of solution through the bed. Reduction of Cr(VI) to Cr(III) within the biosorbent appeared to be the removal mechanism. Depletion rate of Cr(VI) from, and release of reduced Cr(III) ions into the aqueous phase, was influenced by mass transfer resistance besides pH and packing depth. A mathematical model considering the reduction reaction to be irreversible and incorporating intraparticle and external phase mass transfer resistances represented the experimental data adequately. The study indicated that the limitations of fixed bed contactor operating under terrestrial gravity in intensifying mass transfer rates for this system can be overcome with rotating packed bed due to liquid flow under centrifugal acceleration.

Note: "Lock-in accelerometry" to follow sink dynamics in shaken granular matter.

PubMed

Sánchez-Colina, G; Alonso-Llanes, L; Martínez, E; Batista-Leyva, A J; Clement, C; Fliedner, C; Toussaint, R; Altshuler, E

2014-12-01

Understanding the penetration dynamics of intruders in granular beds is relevant not only for fundamental physics, but also for geophysical processes and construction on sediments or granular soils in areas potentially affected by earthquakes. While the penetration of intruders in two dimensional (2D) laboratory granular beds can be followed using video recording, this is useless in three dimensional (3D) beds of non-transparent materials such as common sand. Here, we propose a method to quantify the sink dynamics of an intruder into laterally shaken granular beds based on the temporal correlations between the signals from a reference accelerometer fixed to the shaken granular bed, and a probe accelerometer deployed inside the intruder. Due to its analogy with the working principle of a lock-in amplifier, we call this technique lock-in accelerometry.

Addition of Alarm Pheromone Components Improves the Effectiveness of Desiccant Dusts Against Cimex lectularius

PubMed Central

BENOIT, JOSHUA B.; PHILLIPS, SETH A.; CROXALL, TRAVIS J.; CHRISTENSEN, BRADY S.; YODER, JAY A.; DENLINGER, DAVID L.

2009-01-01

We demonstrate that the addition of bed bug, Cimex lectularius, alarm pheromone to desiccant formulations greatly enhances their effectiveness during short-term exposure. Two desiccant formulations, diatomaceous earth (DE) and Dri-die (silica gel), were applied at the label rate with and without bed bug alarm pheromone components, (E)-2-hexenal, (E)-2-octenal, and a (E)-2-hexenal:(E)-2-octenal blend. First-instar nymphs and adult females were subjected to 10-min exposures, and water loss rates were used to evaluate the response. Optimal effectiveness was achieved with a pheromone concentration of 0.01 M. With Dri-die alone, the water loss was 21% higher than in untreated controls, and water loss increased nearly two times with (E)-2-hexenal and (E)-2-octenal and three times with the (E)-2-hexenal: (E)-2-octenal blend. This shortened survival of first-instar nymphs from 4 to 1 d, with a similar reduction noted in adult females. DE was effective only if supplemented with pheromone, resulting in a 50% increase in water loss over controls with the (E)-2-hexenal:(E)-2-octenal blend, and a survival decrease from 4 to 2 d in first-instar nymphs. Consistently, the addition of the pheromone blend to desiccant dust was more effective than adding either component by itself or by using Dri-die or DE alone. Based on observations in a small microhabitat, the addition of alarm pheromone components prompted bed bugs to leave their protective harborages and to move through the desiccant, improving the use of desiccants for control. We concluded that short exposure to Dri-die is a more effective treatment against bed bugs than DE and that the effectiveness of the desiccants can be further enhanced by incorporation of alarm pheromone. Presumably, the addition of alarm pheromone elevates excited crawling activity, thereby promoting cuticular changes that increase water loss. PMID:19496429

Ion wind generation and its application to drying of wild Ginger slices (Curcuma Xanthorhiza)

NASA Astrophysics Data System (ADS)

Sumariyah; Khuriati, Ainie; Fachriyah, Enny

2018-05-01

Temulawak or wild ginger is a herbal medicinal derived from lndonesia original. Wild ginger contains include an active compound as curcuminoid and antioxidant oleoresin components having a special quality to take care of health from various diseases. Drying is the important process to produce wild ginger (Curcuma xanthorrhiza) simplicia as raw material herbal medicine. In this study, has been dried of wild ginger using ion wind which yielded from corona discharge utilizing pin-multi ring concentred electrodes. Corona discharge was generated by using the fixed DC high voltage of 4,3 kV and drying was done at the distance between the fixed electrodes of 4 mm. Shaped of the five temulawak slices is a circle with a thickness of 2 mm and the diameter of 10 mm - 30 mm with 5 mm diameter interval. The sliced temulawak is placed just below the concentric multi-ring electrode and is 2 mm in distance. The wild ginger slices were dried with time varied 5-65 minutes with time interval 5 minutes. The researched result of drying of wild ginger slices obtained drying rate and shrinkage is inversely proportional to drying time.

Herd-level risk factors for hock injuries in freestall-housed dairy cows in the northeastern United States and California.

PubMed

Barrientos, A K; Chapinal, N; Weary, D M; Galo, E; von Keyserlingk, M A G

2013-06-01

The aim of this study was to investigate the associations between management and facility design factors and the prevalence of hock injuries in high-producing dairy cows in 76 freestall herds in the northeastern United States (NE-US; Vermont, New York, Pennsylvania) and California (CA). One group of high-production multiparous cows was monitored on each farm, and data on management, facility and stall design, and the conditions of the hocks were collected. Focal cows [n=38 ± 3 (mean ± standard deviation)] were evaluated for hock injuries using a 3-point scale (where 1=healthy and 3=evidently swollen or severe injury). Measures associated with the proportion (logit-transformed) of cows having injuries (score ≥ 2) or severe injuries (score=3) at the univariable level were submitted to multivariable general linear models. In NE-US, overall hock injuries increased with the percentage of stalls with fecal contamination [odds ratio (OR)=1.26; 95% confidence interval (CI)=1.02-1.54, for a 10% increase], and with the use of sawdust as bedding (OR=3.47; CI=1.14-10.62), and decreased with deep bedding (i.e., at least 10 cm depth of any type of bedding; OR=0.05; CI=0.02-0.14), use of sand as bedding (OR=0.06; CI=0.02-0.15), bedding dry matter (DM) ≥ 83.9% (OR=0.08; CI=0.03-0.20), and access to pasture during the dry period (OR=0.17; CI=0.05-0.53). When these variables were submitted to a multivariable model, the presence of deep bedding was the only factor that remained significant, explaining 54% of the variation in overall injuries. Severe hock injuries increased with the use of automatic scrapers (OR=2.29; CI=1.11-4.71) and the percentage of stalls with fecal contamination (OR=1.14; CI=1.00-1.31, for a 10% increase), and decreased with sand bedding (OR=0.22; CI=0.10-0.49), deep bedding (OR=0.24; CI=0.11-0.52), bedding DM ≥ 83.9% (OR=0.28; CI=0.14-0.58), and access to pasture during the dry period (OR=0.42; CI=0.18-0.97). The final multivariable model, which explained 36% of the variation in severe hock injuries, included the use of automatic scrapers and deep bedding. In CA, stall stocking density (OR=1.41; CI=1.00-2.01, for a 10% increase) and poor bedding maintenance (OR=1.08; CI=1.01-1.16, for a 2.5-cm decrease in depth of deep-bedded stalls) were associated with an increase of overall and severe hock injuries, respectively. Deep-bedded and well-maintained stalls reduce the risk of hock injuries. Regional variation in risk factors for these injuries should be considered when formulating on-farm recommendations. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

The dependence of the CO2 removal efficiency of LiOH on humidity and mesh size. [in spacecraft life support systems

NASA Technical Reports Server (NTRS)

Davis, S. H.; Kissinger, L. D.

1978-01-01

The effect of humidity on the CO2 removal efficiency of small beds of anhydrous LiOH has been studied. Experimental data taken in this small bed system clearly show that there is an optimum humidity for beds loaded with LiOH from a single lot. The CO2 efficiency falls rapidly under dry conditions, but this behavior is approximately the same in all samples. The behavior of the bed under wet conditions is quite dependent on material size distribution. The presence of large particles in a sample can lead to rapid fall off in the CO2 efficiency as the humidity increases.

Countercurrent fixed-bed gasification of biomass at laboratory scale

DOE Office of Scientific and Technical Information (OSTI.GOV)

Di Blasi, C.; Signorelli, G.; Portoricco, G.

1999-07-01

A laboratory-scale countercurrent fixed-bed gasification plant has been designed and constructed to produce data for process modeling and to compare the gasification characteristics of several biomasses (beechwood, nutshells, olive husks, and grape residues). The composition of producer gas and spatial temperature profiles have been measured for biomass gasification at different air flow rates. The gas-heating value always attains a maximum as a function of this operating variable, associated with a decrease of the air-to-fuel ratio. Optical gasification conditions of wood and agricultural residues give rise to comparable gas-heating values, comprised in the range 5--5.5 MJ/Nm{sup 3} with 28--30% CO, 5--7%more » CO{sub 2}, 6--8% H{sub 2}, 1--2% CH{sub 4}, and small amounts of C{sub 2}- hydrocarbons (apart from nitrogen). However, gasification of agricultural residues is more difficult because of bed transport, partial ash sintering, nonuniform flow distribution, and the presence of a muddy phase in the effluents, so that proper pretreatments are needed for largescale applications.« less

Use of laterite for the removal of fluoride from contaminated drinking water.

PubMed

Sarkar, Mitali; Banerjee, Aparna; Pramanick, Partha Pratim; Sarkar, Asit R

2006-10-15

The effects of different operational variables on the mechanistic function of laterite in removal of fluoride have been investigated. Thermodynamic parameters such as free energy change, enthalpy, and entropy of the process, as well as the sorption isotherm, were evaluated. The extent of solute removal is determined by initial solute concentration, operational conditions, laterite dose, and solution pH. For a fixed set of experimental conditions, a model equation is developed from which the percent removal corresponding to each load of fluoride is determined. The mechanism of fluoride adsorption is governed by the zero point charge of laterite and follows a first-order rate equation. pH has a vital role influencing the surface characteristics of laterite. To simulate the flow dynamics, fluoride solution was run through a fixed bed column. The pattern of breakthrough curves for different influent fluoride concentration, pH, and column bed height was characterized. The column efficiency was tested from the bed depth-service time model. The elution of the retained fluoride was studied and the effectiveness of column operation was determined by the retention-elution cycles.

40 CFR 60.734 - Monitoring of emissions and operations.

Code of Federal Regulations, 2010 CFR

2010-07-01

... operator of an affected facility subject to the provisions of this subpart who uses a dry control device to... control device. (b) In lieu of a continuous opacity monitoring system, the owner or operator of a ball... vermiculite fluid bed dryer, or a vermiculite rotary dryer who uses a dry control device may have a certified...

Using Remote-sensing to Survey Topography and Morphologic Change on Large Braided River Beds

NASA Astrophysics Data System (ADS)

Maurice, D.; Hicks, M.; Shankar, U.

2007-12-01

Since 1999 we have made extensive use of a variety of remote-sensing technologies to survey bed topography over reaches of large braided gravel-bed rivers on the east coast of New Zealand's South Island. The motivations have been (i) to collect input and validation data for 2-d hydrodynamic models for quantifying in-stream physical habitat and for predicting flood levels and (ii) to survey spatially-distributed riverbed erosion and deposition in order to estimate bedload fluxes by the 'morphological' method. Typical applications have been to river reaches 3-4 km long and 1 km wide, with grid cells from 1-5 m. We use different techniques to survey dry and wet areas of braided riverbed. For dry areas, we have used digital photogrammetry and infra-red airborne LiDAR. For wetted channels, we have generally used ortho-rectified colour imagery or multi-spectral scanning to map water depth, then we map bed topography by subtracting the water depth from a DEM of the water surface obtained from photogrammetry or LiDAR. The imagery is calibrated to water depth using field measurements on the day of imagery acquisition. Surveys are undertaken during low flows to maximise bed exposure. We use ground-based RTK-GPS and echo-sounding to collect calibration and validation data, and sometimes simply use these methods to survey the wetted areas. Orthoimagery at multiple river flows is used to validate 2-d model results. We have been able to achieve elevation accuracies at interpolated points of the order of 10-15 cm for dry areas. This accuracy typically degrades to 20-30 cm for wetted areas. Our experience has exposed a number of issues relating to survey accuracy and practicality at large river scales. These include: changing geoidal models between surveys; local systematic error with photogrammetric model mosaics; geospatial synchronisation of multi-platform data; time-synchronisation of LiDAR and imagery- collecting aeroplanes and suitable weather and river conditions; confusions in water depth mapping; and the critical importance of good data at key hydraulic controls for eco-hydrologic applications. We suggest that high resolution bathymetric LiDAR offers the best potential for future surveys in large river reaches. While the current bathymetry LiDAR systems do not appear to deliver a significantly better accuracy of submerged bed elevations than we have achieved with mixed-technology approaches for dry and wet areas, and their cost remains high, a one-stop package is hard to beat in terms of practicality and data synchronisation.

Pulsed atmospheric fluidized bed combustor apparatus and process

DOEpatents

Mansour, Momtaz N.

1992-01-01

A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g. organic and medical waste, drying, calcining and the like.

Dry Stream Reaches in Carbonate Terranes: Surface Indicators of Ground-Water Reservoirs

USGS Publications Warehouse

Brahana, J.V.; Hollyday, E.F.

1988-01-01

In areas where dry stream reaches occur, subsurface drainage successfully competes with surface drainage, and sheet-like dissolution openings have developed parallel to bedding creating the ground-water reservoir. Union Hollow in south-central Tennessee is the setting for a case study that illustrates the application of the dry stream reach technique. In this technique, dry stream reach identification is based on two types of readily acquired information: remotely sensed black and white infrared aerial photography; and surface reconnaissance of stream channel characteristics. Test drilling in Union Hollow subsequent to identification of the dry reach proved that a localized ground-water reservoir was present.

Effects of physical interventions on house dust mite allergen levels in carpet, bed, and upholstery dust in low-income, urban homes.

PubMed Central

Vojta, P J; Randels, S P; Stout, J; Muilenberg, M; Burge, H A; Lynn, H; Mitchell, H; O'Connor, G T; Zeldin, D C

2001-01-01

House dust mite allergen exposure is a postulated risk factor for allergic sensitization, asthma development, and asthma morbidity; however, practical and effective methods to mitigate these allergens from low-income, urban home environments remain elusive. The purpose of this study was to assess the feasibility and effectiveness of physical interventions to mitigate house dust mite allergens in this setting. Homes with high levels of house dust mite allergen (Der f 1 + Der p 1 > or = 10 microg/g dust by enzyme-linked immunosorbent assay) in the bed, bedroom carpet, and/or upholstered furniture were enrolled in the study. Carpets and upholstered furniture were subjected to a single treatment of either dry steam cleaning plus vacuuming (carpet only) or intensive vacuuming alone. Bed interventions consisted of complete encasement of the mattress, box spring, and pillows plus either weekly professional or in-home laundering of nonencased bedding. Dust samples were collected at baseline and again at 3 days (carpet and upholstery only) and 2, 4, and 8 weeks posttreatment. We compared pretreatment mean allergen concentrations and loads to posttreatment values and performed between-group analyses after adjusting for differences in the pretreatment means. Both dry steam cleaning plus vacuuming and vacuuming alone resulted in a significant reduction in carpet house dust mite allergen concentration and load (p < 0.05). Levels approached pretreatment values by 4 weeks posttreatment in the intensive vacuuming group, whereas steam cleaning plus vacuuming effected a decrease that persisted for up to 8 weeks. Significant decreases in bed house dust mite allergen concentration and load were obtained in response to encasement and either professional or in-home laundering (p < 0.001). Between-group analysis revealed significantly less postintervention house dust mite allergen load in professionally laundered compared to home-laundered beds (p < 0.05). Intensive vacuuming and dry steam cleaning both caused a significant reduction in allergen concentration and load in upholstered furniture samples (p < 0.005). Based on these data, we conclude that physical interventions offer practical, effective means of reducing house dust mite allergen levels in low-income, urban home environments. PMID:11564617

Chronic sublethal effects of San Francisco Bay sediments on nereis (neanthes) arenaceodentata; bioaccumulation from bedded sediments. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moore, D.; Dillon, T.M.

1993-09-01

In previous studies with San Francisco Bay sediments, minimal chronic sublethal effects were detected (Miscellaneous Paper D-93-1 and another Miscellaneous Paper in preparation by Moore and Dillon). To ensure that the lack of effects was not due to a lack of contaminant uptake, a bioaccumulation experiment was conducted. Bioaccumulation from bedded sediments was evaluated following a 9-week exposure with the marine polychaete worm Nereis (Neanthes) arenaceodentata. Two sediments were evaluated, a contaminated San Francisco Bay test sediment and a clean control sediment from Sequim, WA. Animals were exposed as early juveniles through adulthood. Tissues were analyzed for metals, polyaromatic hydrocarbonsmore » (PAHs), polychlorinated biphenyls (PCBs), and pesticides. Worms exposed to the contaminated San Francisco Bay sediment had significantly higher tissue residues of silver (0.30 mg/kg dry weight) and tributyltin (0.298 mg/kg dry weight). Conversely, tissue residues of control animals were significantly higher in cadmium (0.67 mg/kg dry weight) and lead (1.89 mg/kg dry weight). Small Amounts (0.02 mg/kg dry weight) of aldrin and dieldrin were measured in worms exposed to the contaminated sediment, while dieldrin and 8-BHC were found in Bioaccumulation, Neanthes, Chronic sublethal, San Francisco Bay, Dredged, Material, Sediment.« less

Sediment entrainment by debris flows: In situ measurements from the headwaters of a steep catchment

USGS Publications Warehouse

McCoy, S.W.; Kean, Jason W.; Coe, Jeffrey A.; Tucker, G.E.; Staley, Dennis M.; Wasklewicz, T.A.

2012-01-01

Debris flows can dramatically increase their volume, and hence their destructive potential, by entraining sediment. Yet quantitative constraints on rates and mechanics of sediment entrainment by debris flows are limited. Using an in situ sensor network in the headwaters of a natural catchment we measured flow and bed properties during six erosive debris-flow events. Despite similar flow properties and thicknesses of bed sediment entrained across all events, time-averaged entrainment rates were significantly faster for bed sediment that was saturated prior to flow arrival compared with rates for sediment that was dry. Bed sediment was entrained from the sediment-surface downward in a progressive fashion and occurred during passage of dense granular fronts as well as water-rich, inter-surge flow.En massefailure of bed sediment along the sediment-bedrock interface was never observed. Large-magnitude, high-frequency fluctuations in total normal basal stress were dissipated within the upper 5 cm of bed sediment. Within this near surface layer, concomitant fluctuations in Coulomb frictional resistance are expected, irrespective of the influence of pore fluid pressure or fluctuations in shear stress. If the near-surface sediment was wet as it was overridden by a flow, additional large-magnitude, high-frequency pore pressure fluctuations were measured in the near-surface bed sediment. These pore pressure fluctuations propagated to depth at subsonic rates and in a diffusive manner. The depth to which large excess pore pressures propagated was typically less than 10 cm, but scaled as (D/fi)0.5, in which D is the hydraulic diffusivity and fi is the frequency of a particular pore pressure fluctuation. Shallow penetration depths of granular-normal-stress fluctuations and excess pore pressures demonstrate that only near-surface bed sediment experiences the full dynamic range of effective-stress fluctuations, and as a result, can be more easily entrained than deeper sediment. These data provide robust tests for mechanical models of entrainment and demonstrate that a debris flow over wet bed sediment will be larger than the same flow over dry bed sediment.

In-line monitoring of granule moisture in fluidized-bed dryers using microwave resonance technology.

PubMed

Buschmüller, Caroline; Wiedey, Wolfgang; Döscher, Claas; Dressler, Jochen; Breitkreutz, Jörg

2008-05-01

This is the first report on in-line moisture measurement of pharmaceutical products by microwave resonance technology. In order to meet the FDA's PAT approach, a microwave resonance sensor appropriate for pharmaceutical use was developed and implemented into two different fluidized-bed dryers. The novel sensor enables a continuous moisture measurement independent from the product density. Hence, for the first time precise real time determination of the moisture in pharmaceutical granules becomes possible. The qualification of the newly developed sensor was performed by drying placebo granules under experimental conditions and the validation using drug loaded granules under real process conditions. The results of the investigations show good correlations between water content of the granules determined by the microwave resonance sensor and both reference methods, loss on drying by infrared light exposure and Karl Fischer titration. Furthermore, a considerable time saving in the drying process was achieved through monitoring the residual water content continuously by microwave resonance technology instead of the formerly used discontinuous methods.

Impact of projectiles of different geometries on dry granular media using DEM simulations

NASA Astrophysics Data System (ADS)

Vajrala, Spandana; Bagheri, Hosain; Emady, Heather; Marvi, Hamid; Particulate Process; Product Design Group Team; Birth Lab Collaboration

Recently, several studies involving numerical and experimental methods have focused on the study of impact dynamics in both dry and wet granular media. Most of these studies considered the impact of spherical projectiles under different conditions, while representative models could involve more complex shapes. Examples include such things as an animal's foot impacting sand or an asteroid hitting the ground. Dropping different shaped geometries with conserved density, volume and velocity on a granular bed may experience contrasting drag forces upon penetration. This is the result of the difference in the surface areas coming in contact with the granular media. Therefore, this work will utilize three-dimensional Discrete Element Modelling (DEM) simulations to observe and compare the impact of different geometries like cylinder and cuboid of same material properties and volume. These geometries will be impacted on a loosely packed non-cohesive dry granular bed with the same impact velocities where the effect of surface area in contact with the granular media will be analyzed upon impact and penetration.

Thermal enhancement cartridge heater modified (TECH Mod) tritium hydride bed development, Part 1 - Design and fabrication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, J.E.; Estochen, E.G.

The Savannah River Site (SRS) tritium facilities have used first generation (Gen1) LaNi{sub 4.25}Al{sub 0.75} (LANA0.75) metal hydride storage beds for tritium absorption, storage, and desorption. The Gen1 design utilizes hot and cold nitrogen supplies to thermally cycle these beds. Second and third generation (Gen2 and Gen3) storage bed designs include heat conducting foam and divider plates to spatially fix the hydride within the bed. For thermal cycling, the Gen2 and Gen3 beds utilize internal electric heaters and glovebox atmosphere flow over the bed inside the bed external jacket for cooling. The currently installed Gen1 beds require replacement due tomore » tritium aging effects on the LANA0.75 material, and cannot be replaced with Gen2 or Gen3 beds due to different designs of these beds. At the end of service life, Gen1 bed desorption efficiencies are limited by the upper temperature of hot nitrogen supply. To increase end-of-life desorption efficiency, the Gen1 bed design was modified, and a Thermal Enhancement Cartridge Heater Modified (TECH Mod) bed was developed. Internal electric cartridge heaters in the new design to improve end-of-life desorption, and also permit in-bed tritium accountability (IBA) calibration measurements to be made without the use of process tritium. Additional enhancements implemented into the TECH Mod design are also discussed. (authors)« less

THERMAL ENHANCEMENT CARTRIDGE HEATER MODIFIED TECH MOD TRITIUM HYDRIDE BED DEVELOPMENT PART I DESIGN AND FABRICATION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klein, J.; Estochen, E.

The Savannah River Site (SRS) tritium facilities have used 1{sup st} generation (Gen1) LaNi{sub 4.25}Al{sub 0.75} (LANA0.75) metal hydride storage beds for tritium absorption, storage, and desorption. The Gen1 design utilizes hot and cold nitrogen supplies to thermally cycle these beds. Second and 3{sup rd} generation (Gen2 and Gen3) storage bed designs include heat conducting foam and divider plates to spatially fix the hydride within the bed. For thermal cycling, the Gen2 and Gen 3 beds utilize internal electric heaters and glovebox atmosphere flow over the bed inside the bed external jacket for cooling. The currently installed Gen1 beds requiremore » replacement due to tritium aging effects on the LANA0.75 material, and cannot be replaced with Gen2 or Gen3 beds due to different designs of these beds. At the end of service life, Gen1 bed desorption efficiencies are limited by the upper temperature of hot nitrogen supply. To increase end-of-life desorption efficiency, the Gen1 bed design was modified, and a Thermal Enhancement Cartridge Heater Modified (TECH Mod) bed was developed. Internal electric cartridge heaters in the new design to improve end-of-life desorption, and also permit in-bed tritium accountability (IBA) calibration measurements to be made without the use of process tritium. Additional enhancements implemented into the TECH Mod design are also discussed.« less

Hydrodynamic characteristics of a novel annular spouted bed with multiple air nozzles

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, X.W.; Hu, G.X.; Li, Y.H.

A novel spouted bed, namely, an annular spouted bed with multiple air nozzles, has been proposed for drying, pyrolysis, and gasification of coal particulates. It consists of two homocentric upright cylinders with some annularly located spouting air nozzles between inner and outer cylinders. Experiments have been performed to study hydrodynamic characteristics of this device. The test materials studied are ash particle, soy bean, and black bean. Three distinct spouting stages have been examined and outlined with the hold-ups increase. In the fully developed spouting stage, three flow behaviors of particles have been observed and delimited. The effects of nozzle modemore » and spouting velocity on the maximum spouting height of the dense-phase region, spoutable static bed height, and spouting pressure drop in the bed have been investigated experimentally.« less

The Potential of Wash-and-Dry Toilets to Improve the Toileting Experience for Nursing Home Residents

ERIC Educational Resources Information Center

Cohen-Mansfield, Jiska; Biddison, James R.

2005-01-01

Purpose: We investigated the feasibility of using a "wash-and-dry" toilet in the nursing home. Design and Methods: We used a controlled comparison baseline-versus-treatment design with 22 female nursing home residents aged 75 and older living in a 562-bed, not-for-profit nursing home facility in Maryland. The Luscence Luxury Lavage…

Application of a Line Laser Scanner for Bed Form Tracking in a Laboratory Flume

NASA Astrophysics Data System (ADS)

de Ruijsscher, T. V.; Hoitink, A. J. F.; Dinnissen, S.; Vermeulen, B.; Hazenberg, P.

2018-03-01

A new measurement method for continuous detection of bed forms in movable bed laboratory experiments is presented and tested. The device consists of a line laser coupled to a 3-D camera, which makes use of triangulation. This allows to measure bed forms during morphodynamic experiments, without removing the water from the flume. A correction is applied for the effect of laser refraction at the air-water interface. We conclude that the absolute measurement error increases with increasing flow velocity, its standard deviation increases with water depth and flow velocity, and the percentage of missing values increases with water depth. Although 71% of the data is lost in a pilot moving bed experiment with sand, still high agreement between flowing water and dry bed measurements is found when a robust LOcally weighted regrESSion (LOESS) procedure is applied. This is promising for bed form tracking applications in laboratory experiments, especially when lightweight sediments like polystyrene are used, which require smaller flow velocities to achieve dynamic similarity to the prototype. This is confirmed in a moving bed experiment with polystyrene.

Bed mixing and leachate recycling strategies to overcome pressure drop buildup in the biofiltration of hydrogen sulfide.

PubMed

Roshani, Babak; Torkian, Ayoob; Aslani, Hasan; Dehghanzadeh, Reza

2012-04-01

The effects of leachate recycling and bed mixing on the removal rate of H(2)S from waste gas stream were investigated. The experimental setup consisted of an epoxy-coated three-section biofilter with an ID of 8 cm and effective bed height of 120 cm. Bed material consisted of municipal solid waste compost and PVC bits with an overall porosity of 54% and dry bulk density of 0.456 g cm(-3). Leachate recycling had a positive effect of increasing elimination capacity (EC) up to 21 g S m(-3) bed h(-1) at recycling rates of 75 ml d(-1), but in the bed mixing period EC declined to 8 g S m(-3) bed h(-1). Pressure drop had a range of zero to 18 mm H(2)O m(-1) in the course of leachate recycling. Accumulation of sulfur reduced removal efficiency and increased pressure drop up to 110 mm H(2)O m(-1) filter during the bed mixing stage. Copyright © 2012 Elsevier Ltd. All rights reserved.

An investigation of the mechanisms of calcination and sulfation in coal-water mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christofides, N.

1990-09-21

The purpose of this investigation is to study the mechanisms of sulfur capture when burning coal-water-limestone mixtures (CWLM) in fluidized beds. Special care is taken to make comparisons with to dry coal and sorbent under comparable experimental conditions. A series of experiments were performed in an eight-inch diameter bubbling fluidized bed combustor to address this problem. 33 refs., 17 figs., 5 tabs.

Pulsed atmospheric fluidized bed combustor apparatus

DOEpatents

Mansour, Momtaz N.

1993-10-26

A pulsed atmospheric fluidized bed reactor system is disclosed and claimed along with a process for utilization of same for the combustion of, e.g. high sulfur content coal. The system affords a economical, ecologically acceptable alternative to oil and gas fired combustors. The apparatus may also be employed for endothermic reaction, combustion of waste products, e.g., organic and medical waste, drying materials, heating air, calcining and the like.

Coal gasification system with a modulated on/off control system

DOEpatents

Fasching, George E.

1984-01-01

A modulated control system is provided for improving regulation of the bed level in a fixed-bed coal gasifier into which coal is fed from a rotary coal feeder. A nuclear bed level gauge using a cobalt source and an ion chamber detector is used to detect the coal bed level in the gasifier. The detector signal is compared to a bed level set point signal in a primary controller which operates in proportional/integral modes to produce an error signal. The error signal is modulated by the injection of a triangular wave signal of a frequency of about 0.0004 Hz and an amplitude of about 80% of the primary deadband. The modulated error signal is fed to a triple-deadband secondary controller which jogs the coal feeder speed up or down by on/off control of a feeder speed change driver such that the gasifier bed level is driven toward the set point while preventing excessive cycling (oscillation) common in on/off mode automatic controllers of this type. Regulation of the bed level is achieved without excessive feeder speed control jogging.

Fully Resolved Simulations of Particle-Bed-Turbulence Interactions in Oscillatory Flows

NASA Astrophysics Data System (ADS)

Apte, S.; Ghodke, C.

2017-12-01

Particle-resolved direct numerical simulations (DNS) are performed to investigate the behavior of an oscillatory flow field over a bed of closely packed fixed spherical particles for a range of Reynolds numbers in transitional and rough turbulent flow regime. Presence of roughness leads to a substantial modification of the underlying boundary layer mechanism resulting in increased bed shear stress, reduction in the near-bed anisotropy, modification of the near-bed sweep and ejection motions along with marked changes in turbulent energy transport mechanisms. Characterization of such resulting flow field is performed by studying statistical descriptions of the near-bed turbulence for different roughness parameters. A double-averaging technique is employed to reveal spatial inhomogeneities at the roughness scale that provide alternate paths of energy transport in the turbulent kinetic energy (TKE) budget. Spatio-temporal characteristics of unsteady particle forces by studying their spatial distribution, temporal auto-correlations, frequency spectra, cross-correlations with near-bed turbulent flow variables and intermittency intermittency in the forces using the concept of impulse are investigated in detail. These first principle simulations provide substantial insights into the modeling of incipient motion of sediments.

Wave Driven Fluid-Sediment Interactions over Rippled Beds

NASA Astrophysics Data System (ADS)

Foster, Diane; Nichols, Claire

2008-11-01

Empirical investigations relating vortex shedding over rippled beds to oscillatory flows date back to Darwin in 1883. Observations of the shedding induced by oscillating forcing over fixed beds have shown vortical structures to reach maximum strength at 90 degrees when the horizontal velocity is largest. The objective of this effort is to examine the vortex generation and ejection over movable rippled beds in a full-scale, free surface wave environment. Observations of the two-dimensional time-varying velocity field over a movable sediment bed were obtained with a submersible Particle Image Velocimetry (PIV) system in two wave flumes. One wave flume was full scale and had a natural sand bed and the other flume had an artificial sediment bed with a specific gravity of 1.6. Full scale observations over an irregularly rippled bed show that the vortices generated during offshore directed flow over the steeper bed form slope were regularly ejected into the water column and were consistent with conceptual models of the oscillatory flow over a backward facing step. The results also show that vortices remain coherent during ejection when the background flow stalls (i.e. both the velocity and acceleration temporarily approach zero). These results offer new insight into fluid sediment interaction over rippled beds.

Effect of bed height and use of hands on trunk angular velocity during the sit-to-stand transfer.

PubMed

Lindemann, Ulrich; van Oosten, Leon; Evers, Jordi; Becker, Clemens; van Dieen, Jaap H; van Lummel, Rob C

2014-01-01

The ability to rise from a chair or bed is critical to an individual's quality of life because it determines functional independence. This study was to investigate the effect of bed height and use of hands on trunk angular velocity and trunk angles during the sit-to-stand (STS) performance. Twenty-four older persons (median age 74 years) were equipped with a body-fixed gyroscopic sensor and stood up from a bed adjusted to different heights, with and without the use of hands at each height. Peak angular velocity and trunk range of motion decreased with increasing bed height (all p ≤ 0.038) and were lower using hands during STS transfer indicating less effort. In conclusion, gyroscopic sensor data of the STS transfer of older persons show differences as an effect of bed height and use of hands. These results provide the rationale for recommending a relatively high bed height for most of the older persons. To minimise the effort during sit-to-stand transfer performance from bed, it is necessary to understand the effect of bed height and use of hands. It is concluded that a relatively high bed height and the use of hands is helpful for most of the older persons during sit-to-stand transfer.

Computational open-channel hydraulics for movable-bed problems

USGS Publications Warehouse

Lai, Chintu; ,

1990-01-01

As a major branch of computational hydraulics, notable advances have been made in numerical modeling of unsteady open-channel flow since the beginning of the computer age. According to the broader definition and scope of 'computational hydraulics,' the basic concepts and technology of modeling unsteady open-channel flow have been systematically studied previously. As a natural extension, computational open-channel hydraulics for movable-bed problems are addressed in this paper. The introduction of the multimode method of characteristics (MMOC) has made the modeling of this class of unsteady flows both practical and effective. New modeling techniques are developed, thereby shedding light on several aspects of computational hydraulics. Some special features of movable-bed channel-flow simulation are discussed here in the same order as given by the author in the fixed-bed case.

Modeling of the adsorption breakthrough behaviors of Pb2+ in a fixed bed of ETS-10 adsorbent.

PubMed

Lv, Lu; Zhang, Yan; Wang, Kean; Ray, Ajay K; Zhao, X S

2008-09-01

On the basis of experimental breakthrough curves of lead ion adsorption on ETS-10 particles in a fixed-bed column, we simulated the breakthrough curves using the two-phase homogeneous diffusion model (TPHDM). Three important model parameters, namely the external mass-transfer coefficient (k(f)), effective intercrystal diffusivity (D(e)), and axial dispersion coefficient (D(L)), were optimally found to be 8.33x10(-5) m/s, 2.57x10(-10) m(2)/s, and 1.93x10(-10) m(2)/s, respectively. A good agreement was observed between the numerical simulation and the experimental results. Sensitivity analysis revealed that the value of D(e) dictates the model performance while the magnitude of k(f) primarily affects the initial breakthrough point of the breakthrough curves.

Effect of small-scale biomass gasification at the state of refractory lining the fixed bed reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janša, Jan, E-mail: jan.jansa@vsb.cz; Peer, Vaclav, E-mail: vaclav.peer@vsb.cz; Pavloková, Petra, E-mail: petra.pavlokova@vsb.cz

The article deals with the influence of biomass gasification on the condition of the refractory lining of a fixed bed reactor. The refractory lining of the gasifier is one part of the device, which significantly affects the operational reliability and durability. After removing the refractory lining of the gasifier from the experimental reactor, there was done an assessment how gasification of different kinds of biomass reflected on its condition in terms of the main factors affecting its life. Gasification of biomass is reflected on the lining, especially through sticking at the bottom of the reactor. Measures for prolonging the lifemore » of lining consist in the reduction of temperature in the reactor, in this case, in order to avoid ash fusion biomass which it is difficult for this type of gasifier.« less

Shifts in Methanogenic Subpopulations Measured with Antibody Probes in a Fixed-Bed Loop Anaerobic Bioreactor Treating Sulfite Evaporator Condensate

PubMed Central

Macario, Alberto J. L.; de Macario, Everly Conway; Ney, Ulrich; Schoberth, Siegfried M.; Sahm, Hermann

1989-01-01

A fixed-bed loop, high-rate anaerobic bioreactor treating sulfite evaporator condensate was sampled when it reached steady state and afterwards following perturbations during a 14-month period. By using immunotechnology, it was observed that shifts in methanogenic subpopulations occurred in association with perturbations, such as restarting and relocating the biomass into a different tank. Methanogens related to Methanobacterium bryantii MoHG and Methanobrevibacter smithii ALI were numerous throughout the observation period, while Methanosarcina mazei S6 and Methanosarcina thermophila TM1 were found in the early and late samples, respectively. Also, Methanobacterium formicicum was more numerous at the top portion of the bioreactor, while Methanobrevibacter arboriphilus AZ and DC were at the bottom. Sample formalinization required for prolonged storage proved suitable for antigen preservation. Images PMID:16347990

Shifts in methanogenic subpopulations measured with antibody probes in a fixed-bed loop anaerobic bioreactor treating sulfite evaporator condensate.

PubMed

Macario, A J; Conway de Macario, E; Ney, U; Schoberth, S M; Sahm, H

1989-08-01

A fixed-bed loop, high-rate anaerobic bioreactor treating sulfite evaporator condensate was sampled when it reached steady state and afterwards following perturbations during a 14-month period. By using immunotechnology, it was observed that shifts in methanogenic subpopulations occurred in association with perturbations, such as restarting and relocating the biomass into a different tank. Methanogens related to Methanobacterium bryantii MoHG and Methanobrevibacter smithii ALI were numerous throughout the observation period, while Methanosarcina mazei S6 and Methanosarcina thermophila TM1 were found in the early and late samples, respectively. Also, Methanobacterium formicicum was more numerous at the top portion of the bioreactor, while Methanobrevibacter arboriphilus AZ and DC were at the bottom. Sample formalinization required for prolonged storage proved suitable for antigen preservation.

Solar photocatalytic disinfection with immobilised TiO(2) at pilot-plant scale.

PubMed

Sordo, Carlos; Van Grieken, Rafael; Marugán, Javier; Fernández-Ibáñez, Pilar

2010-01-01

The photocatalytic disinfection efficiency has been investigated for two immobilized TiO(2) catalytic systems (wall reactor and fixed-bed reactor) in a solar pilot plant. Their performances have been compared with the use of a slurry reactor and the solar disinfection without catalyst. The use of photocatalytic TiO(2) wall reactors does no show clear benefits over the solar disinfection process in the absence of catalyst. The reason is that the efficiency of the solar disinfection is so high that the presence of titania in the reactor wall reduces the global efficiency due to the competition for the absorption of photons. As expected, the maximum efficiency was shown by the slurry TiO(2) reactor, due to the optimum contact between bacteria and catalyst. However, it is noticeable that the use of the fixed-bed reactor leads to inactivation rate quite close to that of the slurry, requiring comparable accumulated solar energy of about 6 kJ L(-1) to achieve a 6-log decrease in the concentration of viable bacteria and allowing a total disinfection of the water (below the detection limit of 1 CFU mL(-1)). Not only the high titania surface area of this configuration is responsible for the bacteria inactivation but the important contribution of the mechanical stress has to be considered. The main advantage of the fixed-bed TiO(2) catalyst is the outstanding stability, without deactivation effects after ten reaction cycles, being readily applicable for continuous water treatment systems.

Effects of sorbent attrition on utilization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keener, T.C.; Khang, Soon-Jai; Lee, S.K.

1992-03-01

Attrition of surface product levers of sulfite/sulfate may be the key to substantially increasing sorbent utilization in new dry scrubbing processes. This conclusion has been reached from research results obtained from new gas/solid contacting methods such as the Circulating Fluidized Bed Absorber and the Limestone Emission Control method. An additional savings may be reduced by the use of large initial sorbent, particle sizes which greatly reduces the cost of grinding and sorbent preparation. The objectives of project 1.7 were then to study attrition of sorbent particles in a systematic fashion in order to determine how to use attrition to increasemore » sorbent utilization. This was to be carried out by the construction of a bench scale fluidized bed where a series of experiments were to be conducted to measure attrition of lime and limestone samples. This has been accomplished and the project proceeded as anticipated. The results indicate that attrition differs for wet and dry conditions for certain sorbents and that these differences are substantial. Under dry conditions, the results of attrition tests on carefully characterized lime samples indicate that mechanical abrasion is the primary attrition mechanism. The rate of attrition is seen to be similar to a first order chemical reaction where the bed mass (or total surface area) is analagous to reactant concentration. A model for mechanical attrition is presented which expresses the rate constant in an Arrhenius type form proportional to a pseudo attrition activation energy and excess gas energy above a minimum level. The value of this pseudo attrition activation energy for lime has been found to be 106 KJ/KG. For the attrition of wetted lime particles in a fluidized bed. the attrition rate has been found to be directly related to the volumetric flow rate of injected water.« less

Low temperature circulating fluidized bed gasification and co-gasification of municipal sewage sludge. Part 1: Process performance and gas product characterization.

PubMed

Thomsen, Tobias Pape; Sárossy, Zsuzsa; Gøbel, Benny; Stoholm, Peder; Ahrenfeldt, Jesper; Frandsen, Flemming Jappe; Henriksen, Ulrik Birk

2017-08-01

Results from five experimental campaigns with Low Temperature Circulating Fluidized Bed (LT-CFB) gasification of straw and/or municipal sewage sludge (MSS) from three different Danish municipal waste water treatment plants in pilot and demonstration scale are analyzed and compared. The gasification process is characterized with respect to process stability, process performance and gas product characteristics. All experimental campaigns were conducted at maximum temperatures below 750°C, with air equivalence ratios around 0.12 and with pure silica sand as start-up bed material. A total of 8600kg of MSS dry matter was gasified during 133h of operation. The average thermal loads during the five experiments were 62-100% of nominal capacity. The short term stability of all campaigns was excellent, but gasification of dry MSS lead to substantial accumulation of coarse and rigid, but un-sintered, ash particles in the system. Co-gasification of MSS with sufficient amounts of cereal straw was found to be an effective way to mitigate these issues as well as eliminate thermal MSS drying requirements. Characterization of gas products and process performance showed that even though gas composition varied substantially, hot gas efficiencies of around 90% could be achieved for all MSS fuel types. Copyright © 2017 Elsevier Ltd. All rights reserved.

Geochemical investigation of the potential for mobilizing non-methane hydrocarbons during carbon dioxide storage in deep coal beds

USGS Publications Warehouse

Kolak, J.J.; Burruss, R.C.

2006-01-01

Coal samples of different rank (lignite to anthracite) were extracted in the laboratory with supercritical CO2 (40 ??C; 10 MPa) to evaluate the potential for mobilizing non-methane hydrocarbons during CO2 storage (sequestration) or enhanced coal bed methane recovery from deep (???1-km depth) coal beds. The total measured alkane concentrations mobilized from the coal samples ranged from 3.0 to 64 g tonne-1 of dry coal. The highest alkane concentration was measured in the lignite sample extract; the lowest was measured in the anthracite sample extract. Substantial concentrations of polycyclic aromatic hydrocarbons (PAHs) were also mobilized from these samples: 3.1 - 91 g tonne-1 of dry coal. The greatest amounts of PAHs were mobilized from the high-volatile bituminous coal samples. The distributions of aliphatic and aromatic hydrocarbons mobilized from the coal samples also varied with rank. In general, these variations mimicked the chemical changes that occur with increasing degrees of coalification and thermal maturation. For example, the amount of PAHs mobilized from coal samples paralleled the general trend of bitumen formation with increasing coal rank. The coal samples yielded hydrocarbons during consecutive extractions with supercritical CO2, although the amount of hydrocarbons mobilized declined with each successive extraction. These results demonstrate that the potential for supercritical CO2 to mobilize non-methane hydrocarbons from coal beds, and the effect of coal rank on this process, are important to consider when evaluating deep coal beds for CO2 storage.

Carbon attrition during the circulating fluidized bed combustion of a packaging-derived fuel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mastellone, M.L.; Arena, U.

1999-05-01

Cylindrical pellets of a market-available packaging-derived fuel, obtained from a mono-material collection of polyethylene terephthalate (PET) bottles, were batchwise fed to a laboratory scale circulating fluidized bed (CFB) combustor. The apparatus, whose riser was 41 mm ID and 4 m high, was operated under both inert and oxidizing conditions to establish the relative importance of purely mechanical attrition and combustion-assisted attrition in generating carbon fines. Silica sand particles of two size distributions were used as inert materials. For each run, carbon load and carbon particle size distribution in the riser and rates of attrited carbon fines escaping the combustor weremore » determined as a function of time. A parallel investigation was carried out with a bubbling fluidized bed (BFB) combustor to point out peculiarities of attrition in CFB combustors. After devolatilization, PET pellets generated fragile aggregates of char and sand, which easily crumbled, leading to single particles, partially covered by a carbon-rich layer. The injected fixed carbon was therefore present in the bed in three phases: an A-phase, made of aggregates of sand and char, an S-phase, made of individual carbon-covered sand particles and an F-phase, made of carbon fines, abraded by the surfaces of the A- and S-phases. The effects of the size of inert material on the different forms under which fixed carbon was present in the bed and on the rate of escape of attrited carbon fines from the combustor were investigated. Features of carbon attrition in CFB and BFB combustors are discussed.« less

Grain velocity of bedload movement in an armored non-uniform mobile bed

NASA Astrophysics Data System (ADS)

Liu, C.

2015-12-01

The velocity of bedload particles, which directly reflects the interaction between flow and sediment, is one of the important parameters to predict sediment transport rate, is also one of the fundamental problems for sediment transport. Many excellent works have been accomplished in this filed. However, the existing researches are mostly based on the artificial fixed bed, few moveable bed studies are focus on uniform sediment bed, these boundary conditions are different from a real river. In this research, an experiment on non-uniform sediment with an armored, moveable bed were carried out in a flume, the range of bed material is from 0.2mm to 20mm. With a special hanging glass and illumination system, the motion particles in the bed were clearly shoot on top of the flume by a video camera, avoiding the interference of waves at the flow surface. The speed of the camera is 50 frames per second. About 7000 unique coordinates of moving particles were determined from 3000 frames of successive pictures, the particle velocity of longitudinal and crosswise directions were obtained from the coordinates. The results show that, the probability density distribution of grain velocities of both directions are similar to that in the uniform sediment, which have an exponent decay trend, whereas the value of cross velocity of particles is clearly greater than that in the uniform sediment condition. Negative particle velocity was recognized in the experiment, it is shown that these negative may occur at two conditions, one is the backflow of fine particles behind the coarser particles, and the other is a state of movement change, such as a particle from static state to motion or vice versa. Furthermore, the particle movement was strongly affected by the arrangement of local coarse particles. The influence of coarser particles to the movement of fine particles also identified by two opposite effects, one is the acceleration effects in a 'tunnel' between pair of series particles, the other is the deceleration effects out of the tunnel, or fine particles captured by the backwater flow just behind a coarse particle. In addition, ensemble particle velocity in the armored bed is distinctly less than which in the fixed bed and uniform bed condition with same particle Reynolds number and Shields parameter. (Supported by(2012BAB04B01;NSFC(11472310))

Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.

PubMed

Cabrera-Lafaurie, Wilman A; Román, Félix R; Hernández-Maldonado, Arturo J

2015-01-23

Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts. Copyright © 2014 Elsevier B.V. All rights reserved.

Flight testing the fixed-wing configuration of the Rotor Systems Research Aircraft (RSRA)

NASA Technical Reports Server (NTRS)

Hall, G. W.; Morris, P. M.

1985-01-01

The Rotor Systems Research Aircraft (RSRA) is a unique research aircraft designed to flight test advanced helicopter rotor system. Its principal flight test configuration is as a compound helicopter. The fixed wing configuration of the RSRA was primarily considered an energy fly-home mode in the event it became necessary to sever an unstable rotor system in flight. While it had always been planned to flight test the fixed wing configuration, the selection of the RSRA as the flight test bed for the X-wing rotor accelerated this schedule. This paper discusses the build-up to, and the test of, the RSRA fixed wing configuration. It is written primarily from the test pilot's perspective.

Analysis of the release process of phenylpropanolamine hydrochloride from ethylcellulose matrix granules V. Release properties of ethylcellulose layered matrix granules.

PubMed

Fukui, Atsuko; Fujii, Ryuta; Yonezawa, Yorinobu; Sunada, Hisakazu

2008-04-01

In the pharmaceutical preparation of a controlled release drug, it is very important and necessary to understand the release properties. In previous papers, a combination of the square-root time law and cube-root law equations was confirmed to be a useful equation for qualitative treatment. It was also confirmed that the combination equation could analyze the release properties of layered granules as well as matrix granules. The drug release property from layered granules is different from that of matrix granules. A time lag occurs before release, and the entire release property of layered granules was analyzed using the combination of the square-root time law and cube-root law equations. It is considered that the analysis method is very useful and efficient for both matrix and layered granules. Comparing the granulation methods, it is easier to control the manufacturing process by tumbling granulation (method B) than by tumbling-fluidized bed granulation (method C). Ethylcellulose (EC) layered granulation by a fluidized bed granulator might be convenient for the preparation of controlled release dosage forms as compared with a tumbling granulator, because the layered granules prepared by the fluidized bed granulator can granulate and dry at the same time. The time required for drying by the fluidized bed granulator is shorter than that by the tumbling granulator, so the fluidized bed granulator is convenient for preparation of granules in handling and shorter processing time than the tumbling granulator. It was also suggested that the EC layered granules prepared by the fluidized bed granulator were suitable for a controlled release system as well as the EC matrix granules.

Freeboard reactions in fluidized coal combustion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walsh, P.M.; Dutta, A.; Beer, J.M.

1984-05-11

The objective of this study was to determine the contribution of freeboard combustion to overall fixed carbon conversion during atmospheric pressure fluidized bed combustion of Kentucky No. 9 high volatile bituminous coal. The progress of the O/sub 2//char reaction in the freeboard was inferred from O/sub 2/ profiles determined by gas sampling. The rates of O/sub 2/ consumption were in good agreement with the O/sub 2//char rate expression of Sergeant and Smith (1973), except at the lowest temperature investigated (964 K). The discrepancy in this case might be due to catalysis of the O/sub 2//char reaction by lime, since thismore » was the first run of the series. Extrapolation of the O/sub 2/ profile to the bed surface using the rate expression of Sergeant and Smith showed that approximately all of the fixed carbon conversion could be accounted for by freeboard combustion. A simple model is proposed in which devolatilization, fragmentation, attrition, and volatile combustion are limited to the bed; with combustion of the finely ground char occurring only in the freeboard. This model predicts O/sub 2/ at the combustor outlet within 60% of the measured values, except in the low temperature/high lime case.« less

Adsorption of Methyl Tertiary Butyl Ether on Granular Zeolites: Batch and Column Studies

PubMed Central

Abu-Lail, Laila; Bergendahl, John A.; Thompson, Robert W.

2010-01-01

Methyl tertiary butyl ether (MTBE) has been shown to be readily removed from water with powdered zeolites, but the passage of water through fixed beds of very small powdered zeolites produces high friction losses not encountered in flow through larger sized granular materials. In this study, equilibrium and kinetic adsorption of MTBE onto granular zeolites, a coconut shell granular activated carbon (CS-1240), and a commercial carbon adsorbent (CCA) sample was evaluated. In addition, the effect of natural organic matter (NOM) on MTBE adsorption was evaluated. Batch adsorption experiments determined that ZSM-5 was the most effective granular zeolite for MTBE adsorption. Further equilibrium and kinetic experiments verified that granular ZSM-5 is superior to CS-1240 and CCA in removing MTBE from water. No competitive-adsorption effects between NOM and MTBE were observed for adsorption to granular ZSM-5 or CS-1240, however there was competition between NOM and MTBE for adsorption onto the CCA granules. Fixed-bed adsorption experiments for longer run times were performed using granular ZSM-5. The bed depth service time model (BDST) was used to analyze the breakthrough data. PMID:20153106

Neural fuzzy modelization of copper removal from water by biosorption in fixed-bed columns using olive stone and pinion shell.

PubMed

Calero, M; Iáñez-Rodríguez, I; Pérez, A; Martín-Lara, M A; Blázquez, G

2018-03-01

Continuous copper biosorption in fixed-bed column by olive stone and pinion shell was studied. The effect of three operational parameters was analyzed: feed flow rate (2-6 ml/min), inlet copper concentration (40-100 mg/L) and bed-height (4.4-13.4 cm). Artificial Neural-Fuzzy Inference System (ANFIS) was used in order to optimize the percentage of copper removal and the retention capacity in the column. The highest percentage of copper retained was achieved at 2 ml/min, 40 mg/L and 4.4 cm. However, the optimum biosorption capacity was obtained at 6 ml/min, 100 mg/L and 13.4 cm. Finally, breakthrough curves were simulated with mathematical traditional models and ANFIS model. The calculated results obtained with each model were compared with experimental data. The best results were given by ANFIS modelling that predicted copper biosorption with high accuracy. Breakthrough curves surfaces, which enable the visualization of the behavior of the system in different process conditions, were represented. Copyright © 2017 Elsevier Ltd. All rights reserved.

Well-balanced high-order centered schemes on unstructured meshes for shallow water equations with fixed and mobile bed

NASA Astrophysics Data System (ADS)

Canestrelli, Alberto; Dumbser, Michael; Siviglia, Annunziato; Toro, Eleuterio F.

2010-03-01

In this paper, we study the numerical approximation of the two-dimensional morphodynamic model governed by the shallow water equations and bed-load transport following a coupled solution strategy. The resulting system of governing equations contains non-conservative products and it is solved simultaneously within each time step. The numerical solution is obtained using a new high-order accurate centered scheme of the finite volume type on unstructured meshes, which is an extension of the one-dimensional PRICE-C scheme recently proposed in Canestrelli et al. (2009) [5]. The resulting first-order accurate centered method is then extended to high order of accuracy in space via a high order WENO reconstruction technique and in time via a local continuous space-time Galerkin predictor method. The scheme is applied to the shallow water equations and the well-balanced properties of the method are investigated. Finally, we apply the new scheme to different test cases with both fixed and movable bed. An attractive future of the proposed method is that it is particularly suitable for engineering applications since it allows practitioners to adopt the most suitable sediment transport formula which better fits the field data.

Competitive adsorption between benzene and ethylene dichloride on activated carbon: The importance of concentration

NASA Astrophysics Data System (ADS)

Miao, T.; Tang, H. M.; Cheng, Z. X.

2018-03-01

In this work we studied breakthroughs of binary mixtures of benzene and ethylene dichloride on fixed activated carbons bed. The results show a series of assault concentrations on activated carbon bed influences the nature of the adsorption competition mechanism. Assault concentration were used to determine how competition of compound distribution. The results are discussed in terms of competing energetic and the underlying molecular mechanisms. The ratio of assault concentrations is main reason for determining selectivity.

Measurement and Modeling of Ecosystem Risk and Recovery for In Situ Treatment of Contaminated Sediments. Phase 3

DTIC Science & Technology

2015-08-01

boundary layer and xPE is the PE thickness (cm). For passive samplers deployed in the sediment bed , the HOC uptake kinetics is also a function of...in sediment beds using performance reference compounds (PRCs) (Adams, Lohmann et al. 2007, Tomaszewski and Luthy 2008, Fernandez, MacFarlane et al...version program was tested for user-friendliness as well as performance. Any reported bugs were fixed, and suggestions on the user-friendliness were

Quarterly technical progress report, April-June 1982

DOE Office of Scientific and Technical Information (OSTI.GOV)

None

1984-04-01

Progress reports are presented for the following tasks: (1) preparation of low-rank coals; application of liquefaction processes to low-rank coals; (2) slagging fixed-bed gasification; (3) atmospheric fluidized-bed combustion of low-rank coal; (4) ash fouling and combustion modification for low-rank coal; (5) combined flue gas cleanup/simultaneous SO/sub x/-NO/sub x/ control; (6) particulate control and hydrocarbons and trace element emissions from low-rank coals; (7) waste characterization and disposal; and (9) exploratory research.

Measurement of the bed material of gravel-bed rivers

USGS Publications Warehouse

Milhous, R.T.; ,

2002-01-01

The measurement of the physical properties of a gravel-bed river is important in the calculation of sediment transport and physical habitat values for aquatic animals. These properties are not always easy to measure. One recent report on flushing of fines from the Klamath River did not contain information on one location because the grain size distribution of the armour could not be measured on a dry river bar. The grain size distribution could have been measured using a barrel sampler and converting the measurements to the same as would have been measured if a dry bar existed at the site. In another recent paper the porosity was calculated from an average value relation from the literature. The results of that paper may be sensitive to the actual value of porosity. Using the bulk density sampling technique based on a water displacement process presented in this paper the porosity could have been calculated from the measured bulk density. The principle topics of this paper are the measurement of the size distribution of the armour, and measurement of the porosity of the substrate. The 'standard' method of sampling of the armour is to do a Wolman-type count of the armour on a dry section of the river bed. When a dry bar does not exist the armour in an area of the wet streambed is to sample and the measurements transformed analytically to the same type of results that would have been obtained from the standard Wolman procedure. A comparison of the results for the San Miguel River in Colorado shows significant differences in the median size of the armour. The method use to determine the porosity is not 'high-tech' and there is a need improve knowledge of the porosity because of the importance of porosity in the aquatic ecosystem. The technique is to measure the in-situ volume of a substrate sample by measuring the volume of a frame over the substrate and then repeated the volume measurement after the sample is obtained from within the frame. The difference in the volumes is the volume of the sample.

Laboratory Testing of a Fluidized-Bed Dry-Scrubbing Process for the Removal of Acidic Gases from a Simulated Incinerator Flue Gas

DTIC Science & Technology

1989-04-01

100 MW). Cost data for two conventional wet processes (limestone and wet lime) are shown in Table 5.1. Table 5.1. Costs for flue gas desulfurization ...Results of short-term dry-scrubbing tests ............... 8 5.1 Costs for flue gas desulfurization systems .............. 15 A.1 Detailed description of...this report is part of an effort by USATHAMA to develop and test a flue gas dry-scrubbing system that can be used as a replacement for wet scrubbers for

Continuous biological waste gas treatment in stirred trickle-bed reactor with discontinuous removal of biomass.

PubMed

Laurenzis, A; Heits, H; Wübker, S; Heinze, U; Friedrich, C; Werner, U

1998-02-20

A new reactor for biological waste gas treatment was developed to eliminate continuous solvents from waste gases. A trickle-bed reactor was chosen with discontinuous movement of the packed bed and intermittent percolation. The reactor was operated with toluene as the solvent and an optimum average biomass concentration of between 5 and 30 kg dry cell weight per cubic meter packed bed (m3pb). This biomass concentration resulted in a high volumetric degradation rate. Reduction of surplus biomass by stirring and trickling caused a prolonged service life and prevented clogging of the trickle bed and a pressure drop increase. The pressure drop after biomass reduction was almost identical to the theoretical pressure drop as calculated for the irregular packed bed without biomass. The reduction in biomass and intermittent percolation of mineral medium resulted in high volumetric degradation rates of about 100 g of toluene m-3pb h-1 at a load of 150 g of toluene m-3pb h-1. Such a removal rate with a trickle-bed reactor was not reported before. Copyright 1998 John Wiley & Sons, Inc.

Simulation of biomass-steam gasification in fluidized bed reactors: Model setup, comparisons and preliminary predictions.

PubMed

Yan, Linbo; Lim, C Jim; Yue, Guangxi; He, Boshu; Grace, John R

2016-12-01

A user-defined solver integrating the solid-gas surface reactions and the multi-phase particle-in-cell (MP-PIC) approach is built based on the OpenFOAM software. The solver is tested against experiments. Then, biomass-steam gasification in a dual fluidized bed (DFB) gasifier is preliminarily predicted. It is found that the predictions agree well with the experimental results. The bed material circulation loop in the DFB can form automatically and the bed height is about 1m. The voidage gradually increases along the height of the bed zone in the bubbling fluidized bed (BFB) of the DFB. The U-bend and cyclone can separate the syngas in the BFB and the flue gas in the circulating fluidized bed. The concentration of the gasification products is relatively higher in the conical transition section, and the dry and nitrogen-free syngas at the BFB outlet is predicted to be composed of 55% H 2 , 20% CO, 20% CO 2 and 5% CH 4 . Copyright © 2016 Elsevier Ltd. All rights reserved.

Short communication: Environmental mastitis pathogen counts in freestalls bedded with composted and fresh recycled manure solids.

PubMed

Cole, K J; Hogan, J S

2016-02-01

An experiment was conducted to compare bacterial counts of environmental mastitis pathogens in composted recycled manure solids bedding with those in fresh recycled manure solids. Eighteen Holstein cows were housed in 1 pen with 18 stalls. One row of 9 freestalls included mattresses and was bedded weekly with composted recycled manure solids. The second row of 9 freestalls included mattresses and was bedded weekly with fresh recycled manure solids. The back one-third of stalls toward the alleyway was covered in 25 to 50 mm of bedding. Samples were taken from the back one-third of 4 stalls for both treatments on d 0, 1, 2, and 6 of each week. After 3 wk, bedding treatments were switched between rows, making the total duration 6 wk. Mean total gram-negative bacterial counts were approximately 0.5 log10 cfu/g of dry matter lower in the composted recycled manure solids on d 0 compared with fresh recycled manure solids. Klebsiella species, coliform, and Streptococcus species counts were at least 1.0 log10 cfu/g of dry matter lower in composted compared with fresh recycled manure solids on d 0. Only gram-negative bacterial counts on d 1 were reduced in composted recycled manure solids compared with fresh recycled manure solids. Differences were not observed between treatments in gram-negative bacterial, coliform, Klebsiella species, or Streptococcus species counts on d 2 and 6. Ash content was higher in composted recycled manure solids compared with fresh recycled manure solids on d 0, 1, 2, and 6. Despite the increase in ash after composting, bacterial counts of mastitis pathogens in composted recycled manure solids were comparable with those in fresh recycled manure when used as freestall bedding. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Biophysics of cochlear implant/MRI interactions emphasizing bone biomechanical properties.

PubMed

Sonnenburg, Robert E; Wackym, Phillip A; Yoganandan, Narayan; Firszt, Jill B; Prost, Robert W; Pintar, Frank A

2002-10-01

The forces exerted during a 1.5-Tesla MRI evaluation on the internal magnet of a cochlear implant (CI) raise concern about the safety for CI recipients. This study determines the magnitude of force required to fracture the floor of a CI receiver bed. Recessed CI beds were drilled to maximum uniform thinness into formalin-fixed and fresh-frozen human calvaria specimens. A Med-El stainless steel CI template mounted to the piston of an electrohydraulic testing device was used to fracture the floor of the implant beds. Force and displacement were measured as a function of time using a digital data acquisition system. Mean force to first failure, displacement to first failure, and minimum thickness, respectively, were: group 1 (formalin-fixed, 0.3-0.4-mm thick [n = 22]), 34.08 N (8.21-59.64 N, standard deviation [SD] 15.41 N), 1.09 mm (0.40-2.16 mm, SD 0.51 mm), 0.36 mm (0.3-0.4 mm, SD 0.05 mm); group 2 (formalin-fixed, 0.5-0.9 mm thick [n = 21]), 52.82 N (20.28-135.53 N, SD 25.29 N), 1.08 mm (0.50-2.28 mm, SD 0.47 mm), 0.58 mm (0.5-0.9 mm, SD 0.12 mm); group 3 (fresh-frozen [n = 9]), 134.13 N (86.44-190.70 N, SD 34.92 N), 1.96 mm (1.47-2.46 mm, SD 0.35 mm), 0.42 mm (0.3-0.6 mm, SD 0.11 mm). The mean magnitude of force required to fracture the floor of a CI bed is significantly greater than those that are generated when a Med-El Combi 40+, CII Bionic Ear CI, or Nucleus Contour CI is placed into a 1.5-Tesla MRI unit.

Bioremoval of heavy metals from industrial effluent by fixed-bed column of red macroalgae.

PubMed

Ibrahim, Wael M; Mutawie, Hawazin H

2013-02-01

Three different species of nonliving red algal biomass Laurancia obtusa, Geldiella acerosa and Hypnea sp. were used to build three types of fixed-bed column for the removal of toxic heavy metal ions such as Cu(2+), Zn(2+), Mn(2+) and Ni(2+) from industrial effluent. In general, the highest efficiency of metal ion bioremoval was recorded for algal column of L. obtusa followed by G. acerosa and the lowest one was recorded for Hypnea sp., with mean removal values of 94%, 85% and 71%, respectively. The obtained results showed that biological treatments of industrial effluents with these algal columns, using standard algal biotest, Pseudokirchneriella subcapitata, were capable of reducing effluent toxicities from 75% to 15%, respectively. Red algal column may be considered as an inexpensive and efficient alternative treatment for conventional removal technology, for sequestering heavy metal ions from industrial effluents.

Biomass gasification for liquid fuel production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Najser, Jan, E-mail: jan.najser@vsb.cz, E-mail: vaclav.peer@vsb.cz; Peer, Václav, E-mail: jan.najser@vsb.cz, E-mail: vaclav.peer@vsb.cz; Vantuch, Martin

2014-08-06

In our old fix-bed autothermal gasifier we tested wood chips and wood pellets. We make experiments for Czech company producing agro pellets - pellets made from agricultural waste and fastrenewable natural resources. We tested pellets from wheat and rice straw and hay. These materials can be very perspective, because they dońt compete with food production, they were formed in sufficient quantity and in the place of their treatment. New installation is composed of allothermal biomass fixed bed gasifier with conditioning and using produced syngas for Fischer - Tropsch synthesis. As a gasifying agent will be used steam. Gas purification willmore » have two parts - separation of dust particles using a hot filter and dolomite reactor for decomposition of tars. In next steps, gas will be cooled, compressed and removed of sulphur and chlorine compounds and carbon dioxide. This syngas will be used for liquid fuel synthesis.« less

Biomass gasification for liquid fuel production

NASA Astrophysics Data System (ADS)

Najser, Jan; Peer, Václav; Vantuch, Martin

2014-08-01

In our old fix-bed autothermal gasifier we tested wood chips and wood pellets. We make experiments for Czech company producing agro pellets - pellets made from agricultural waste and fastrenewable natural resources. We tested pellets from wheat and rice straw and hay. These materials can be very perspective, because they dońt compete with food production, they were formed in sufficient quantity and in the place of their treatment. New installation is composed of allothermal biomass fixed bed gasifier with conditioning and using produced syngas for Fischer - Tropsch synthesis. As a gasifying agent will be used steam. Gas purification will have two parts - separation of dust particles using a hot filter and dolomite reactor for decomposition of tars. In next steps, gas will be cooled, compressed and removed of sulphur and chlorine compounds and carbon dioxide. This syngas will be used for liquid fuel synthesis.

Ash bed level control system for a fixed-bed coal gasifier

DOEpatents

Fasching, George E.; Rotunda, John R.

1984-01-01

An ash level control system is provided which incorporates an ash level meter to automatically control the ash bed level of a coal gasifier at a selected level. The ash level signal from the ash level meter is updated during each cycle that a bed stirrer travels up and down through the extent of the ash bed level. The ash level signal is derived from temperature measurements made by thermocouples carried by the stirrer as it passes through the ash bed and into the fire zone immediately above the ash bed. The level signal is compared with selected threshold level signal to determine if the ash level is above or below the selected level once each stirrer cycle. A first counter is either incremented or decremented accordingly. The registered count of the first counter is preset in a down counter once each cycle and the preset count is counted down at a selected clock rate. A grate drive is activated to rotate a grate assembly supporting the ash bed for a period equal to the count down period to maintain the selected ash bed level. In order to avoid grate binding, the controller provides a short base operating duration time each stirrer cycle. If the ash bed level drops below a selected low level or exceeds a selected high level, means are provided to notify the operator.

Increase in Dry Weight and Total Nitrogen Content in Zea mays and Setaria italica Associated with Nitrogen-fixing Azospirillum spp. 1

PubMed Central

Cohen, Efraim; Okon, Yaacov; Kigel, Jaime; Nur, Israel; Henis, Yigal

1980-01-01

The association between nitrogen-fixing bacteria from the genus Azospirillum and the grasses Zea mays and Setaria italica was investigated in sterilized Leonard-jar assemblies. Nitrogen-fixing bacteria isolated from Cynodon dactylon roots in Israel and Azospirillum brasilense (Sp-7, Sp-80, and Cd) were examined. C2H2 reduction activity was detected in systems containing 0.0 to 0.08 but not in those containing 0.16 gram per liter NH4NO3. The organisms tested significantly increased plant dry weight (50-100%), total N content of leaves (50-100%) and C2H4 production (300-1000 nanomoles C2H4 per plant per hour). Highest C2H2 reduction activities were obtained above 30 C and with high light intensities. Significant increases in S. italica dry weight (DW) and nitrogen (N) content were observed in sand (DW = 80%, N = 150%), sandy loam soil (DW = 80%, N = 75%) and loess (DW = 37%, N = 25%). The results obtained in this work clearly demonstrate the potential benefit of inoculating grasses with Azospirillum. PMID:16661514

Wireless Authentication Protocol Implementation: Descriptions of a Zero-Knowledge Proof (ZKP) Protocol Implementation for Testing on Ground and Airborne Mobile Networks

DTIC Science & Technology

2015-01-01

on AFRL’s small unmanned aerial vehicle (UAV) test bed . 15. SUBJECT TERMS Zero-Knowledge Proof Protocol Testing 16. SECURITY CLASSIFICATION OF...VERIFIER*** edition Version Information: Version 1.1.3 Version Details: Successful ZK authentication between two networked machines. Fixed a bug ...that causes intermittent bignum errors. Fixed a network hang bug and now allows continually authentication at the Verifier. Also now removing

Investigating waste rock, tailings, slag and coal ash clinker as adsorbents for heavy metals: Batch and column studies

NASA Astrophysics Data System (ADS)

Letina, D.; Letshwenyo, W. M.

2018-06-01

Wastewater from the mining industry is a concern because most of the time it contains heavy metals with concentrations above permissible levels, posing a threat to terrestrial and aquatic life. The study was conducted to evaluate the effectiveness of locally available waste materials (waste rock, tailings, coal ash clinker, and slag) generated by BCL (Ltd) mine, a copper and nickel mining and smelting company in Botswana, for removal of nickel and copper from the real mining wastewater. Batch adsorption studies were conducted to establish the adsorptive efficiency and kinetics of each media with respect to nickel and copper ions. The best media was further evaluated through fixed bed column studies at 24 and 48 h empty bed contact time. The results indicate that the percentage removal for coal ash clinker, waste rock, smelter slag and tailings was 98%, 15%, 3% and -3% with respect to copper ions, and 46%, 9%, 7% and 2% with respect to nickel ions for each media respectively. Coal ash clinker followed pseudo first order kinetic model and Langmuir isotherm model with respect to nickel ions indicating the dominance of physisorption and mono layer coverage respectively. The Langmuir separation factor (RL) was 0.37 suggesting favourable adsorption onto the media. Fixed bed column studies revealed that copper was completely retained in the bed at both 24 and 48 h contact times. In the case of nickel, removal efficiency ranged between 83% and 99% when contact time was 48 h and between 68% and 99% when the contact time was reduced to 24 h. Breakthrough was not reached after 19 bed volumes. It can be concluded that coal ash clinker is a better candidate for the removal of copper and nickel ions from mining wastewater.

Mathematical modeling of the adsorption/desorption characteristics of anthocyanins from muscadine (Vitis rotundifolia cv. Noble) juice pomace on Amberlite FPX66 resin in a fixed bed column.

PubMed

Uzdevenes, Chad G; Gao, Chi; Sandhu, Amandeep K; Yagiz, Yavuz; Gu, Liwei

2018-03-24

Muscadine grape pomace, a by-product of juicing and wine-making, contains significant amounts of anthocyanin 3,5-diglucosides, known to be beneficial to human health. The objective of this research was to use mathematical modeling to investigate the adsorption/desorption characteristics of these anthocyanins from muscadine grape pomace on Amberlite FPX66 resin in a fixed bed column. Anthocyanins were extracted using hot water and ultrasound, and the extracts were loaded onto a resin column at five bed depths (5, 6, 8, 10 and 12 cm) using three flow rates (4, 6 and 8 mL min -1 ). It was found that adsorption on the column fitted the bed depth service time (BDST) model and the empty bed residence time (EBRT) model. Desorption was achieved by eluting the column using ethanol at four concentrations (25, 40, 55 and 70% v/v) and could be described with an empirical sigmoid model. The breakthrough curves of anthocyanins fitted the BDST model for all three flow rates with R 2 values of 0.983, 0.992 and 0.984 respectively. The EBRT model was successfully employed to find the operating lines, which allow for column scale-up while still achieving similar results to those found in a laboratory operation. Desorption with 40% (v/v) ethanol achieved the highest recovery rate of anthocyanins at 79.6%. The mathematical models established in this study can be used in designing a pilot/industrial- scale column for the separation and concentration of anthocyanins from muscadine juice pomace. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Batch and fixed-bed adsorption of tartrazine azo-dye onto activated carbon prepared from apricot stones

NASA Astrophysics Data System (ADS)

Albroomi, H. I.; Elsayed, M. A.; Baraka, A.; Abdelmaged, M. A.

2017-07-01

This work describes the potential of utilizing prepared activated carbon from apricot stones as an efficient adsorbent material for tartrazine (TZ) azo-dye removal in a batch and dynamic adsorption system. The results revealed that activated carbons with well-developed surface area (774 m2/g) and pore volume (1.26 cm3/g) can be manufactured from apricot stones by H3PO4 activation. In batch experiments, effects of the parameters such as initial dye concentration and temperature on the removal of the dye were studied. Equilibrium was achieved in 120 min. Adsorption capacity was found to be dependent on the initial concentration of dye solution, and maximum adsorption was found to be 76 mg/g at 100 mg/L of TZ. The adsorption capacity at equilibrium ( q e) increased from 22.6 to 76 mg/g with an increase in the initial dye concentrations from 25 to 100 mg/L. The thermodynamic parameters such as change in free energy (Δ G 0), enthalpy (Δ H 0) and entropy (Δ S 0) were determined and the positive value of (Δ H) 78.1 (K J mol-1) revealed that adsorption efficiency increased with an increase in the process temperature. In fixed-bed column experiments, the effect of selected operating parameters such as bed depth, flow rate and initial dye concentration on the adsorption capacity was evaluated. Increase in bed height of adsorption columns leads to an extension of breakthrough point as well as the exhaustion time of adsorbent. However, the maximum adsorption capacities decrease with increases of flow rate. The breakthrough data fitted well to bed depth service time and Thomas models with high coefficient of determination, R 2 ≥ 94.

Large pterygium surgery: When coverage of the scleral bed justifies graft rotation.

PubMed

Gargallo-Benedicto, A; Hernández Pérez, D; Olate-Pérez, Á; Betancur-Delgado, E; Cerdà-Ibáñez, M; Duch-Samper, A

2016-10-01

To perform a 12 month follow-up study to assess the safety and effectiveness of resection and conjunctival autograft fixed with Tissucol® in selected cases of large pterygium. The orientation of the graft was adapted to the morphology of the scleral bed for a better coverage free of traction, with limbal position being lost. A prospective, non-comparative study of 10 cases of grade II or superior pterygium (7 primary, 3 recurrent) with at least 8mm of limbal extension. A wide scleral bed was obtained after pterygium and Tenon resection, with larger grafts being required to cover the defects. A superior conjunctival autograft was harvested and fixed to bare sclera using Tissucol. The orientation was adapted to the morphology of the scleral bed and limbal position was lost. Patients were periodically assessed for recurrence and complications for a period of 12 months. Minor complications occurred in 4 eyes. In one case a buttonhole was formed during dissection of the graft. Two presented with small limbal dehiscence, but epithelialisation was completed in the first week. In a third case, it was necessary to increase topical corticosteroids for pyogenic granuloma on the donor site, with secondary increased intraocular pressure (IOP). There were no recurrences after 12 months follow-up. A conjunctival graft of appropriate size adapted to the morphology of the scleral bed to ensure good coverage free of tension, provides good surgical results in selected cases of pterygium, regardless of the conservation the limbal orientation, with no recurrences after one year follow-up. Copyright © 2016 Sociedad Española de Oftalmología. Published by Elsevier España, S.L.U. All rights reserved.

Numerical modelling of biomass combustion: Solid conversion processes in a fixed bed furnace

NASA Astrophysics Data System (ADS)

Karim, Md. Rezwanul; Naser, Jamal

2017-06-01

Increasing demand for energy and rising concerns over global warming has urged the use of renewable energy sources to carry a sustainable development of the world. Bio mass is a renewable energy which has become an important fuel to produce thermal energy or electricity. It is an eco-friendly source of energy as it reduces carbon dioxide emissions. Combustion of solid biomass is a complex phenomenon due to its large varieties and physical structures. Among various systems, fixed bed combustion is the most commonly used technique for thermal conversion of solid biomass. But inadequate knowledge on complex solid conversion processes has limited the development of such combustion system. Numerical modelling of this combustion system has some advantages over experimental analysis. Many important system parameters (e.g. temperature, density, solid fraction) can be estimated inside the entire domain under different working conditions. In this work, a complete numerical model is used for solid conversion processes of biomass combustion in a fixed bed furnace. The combustion system is divided in to solid and gas phase. This model includes several sub models to characterize the solid phase of the combustion with several variables. User defined subroutines are used to introduce solid phase variables in commercial CFD code. Gas phase of combustion is resolved using built-in module of CFD code. Heat transfer model is modified to predict the temperature of solid and gas phases with special radiation heat transfer solution for considering the high absorptivity of the medium. Considering all solid conversion processes the solid phase variables are evaluated. Results obtained are discussed with reference from an experimental burner.

Gas purification in the dense phase at the CATS terminal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Openshaw, P.J.; Carnell, P.J.H.; Rhodes, E.F.

The purification and transportation of natural gas at very high pressures can help to minimize the capital cost of pipelines and processing equipment. However, complex mixtures of hydrocarbons undergo unusual phase changes, such as retrograde condensation, as the temperature and pressure are altered. The Central Area Transmission System (CATS) is a joint venture of Amoci, BG, Amerada Hess, Phillips, Agip and Fina operated by Amoco on behalf of the owners. The design of the CATS terminal has provided an interesting processing challenge. The terminal receives a total of 1.6 Bscf/d of rich gas from a number of offshore fields. Allmore » are relatively sweet but the small amounts of H{sub 2}S and Hg are removed. Fixed bed technology was selected as the most economic purification process, while minimizing hydrocarbon loss and operator involvement. Conventionally, the raw gas would be split into the different hydrocarbon fractions and each would be processed separately. This would require the installation of a large number of reactors. A more elegant solution is to treat the gas on arrival at the terminal in the dense phase. This option raised questions around whether a fixed bed would be prone to fouling, could the pressure drop be kept low enough to avoid phase separation and would inadvertent wetting by condensation cause problems. Details are given of the test work carried out to prove the viability of using fixed bed technology for dense phase gas processing, the eventual design adopted and the performance over the first year of service.« less

Carbon Cloth Supported Nano-Mg(OH)2 for the Enrichment and Recovery of Rare Earth Element Eu(III) From Aqueous Solution.

PubMed

Li, Yinong; Tian, Chen; Liu, Weizhen; Xu, Si; Xu, Yunyun; Cui, Rongxin; Lin, Zhang

2018-01-01

Nano-Mg(OH) 2 is attracting great attention as adsorbent for pre-concentration and recovery of rare earth elements (REEs) from low-concentration solution, due to its superior removal efficiency for REEs and environmental friendliness. However, the nanoparticles also cause some severe problems during application, including aggregation, blockage in fixed-bed column, as well as the difficulties in separation and reuse. Herein, in order to avoid the mentioned problems, a carbon cloth (CC) supported nano-Mg(OH) 2 (nano-Mg(OH) 2 @CC) was synthesized by electrodeposition. The X-ray diffraction and scanning electron microscopy analysis demonstrated that the interlaced nano-sheet of Mg(OH) 2 grew firmly and uniformly on the surface of carbon cloth fibers. Batch adsorption experiments of Eu(III) indicated that the nano-Mg(OH) 2 @CC composite maintained the excellent adsorption performance of nano-Mg(OH) 2 toward Eu(III). After adsorption, the Eu containing composite was calcined under nitrogen atmosphere. The content of Eu 2 O 3 in the calcined material was as high as 99.66%. Fixed-bed column experiments indicated that no blockage for Mg(OH) 2 @CC composite was observed during the treatment, while the complete blockage of occurred to nano-Mg(OH) 2 at an effluent volume of 240 mL. Moreover, the removal efficiency of Mg(OH) 2 @CC was still higher than 90% until 4,200 mL of effluent volume. This work provides a promising method for feasible application of nanoadsorbents in fixed-bed process to recycle low-concentration REEs from wastewater.

Carbon Cloth Supported Nano-Mg(OH)2 for the Enrichment and Recovery of Rare Earth Element Eu(III) from Aqueous Solution

NASA Astrophysics Data System (ADS)

Li, Yinong; Tian, Chen; Liu, Weizhen; Xu, Si; Xu, Yunyun; Cui, Rongxin; Lin, Zhang

2018-04-01

Nano-Mg(OH)2 is attracting great attention as adsorbent for pre-concentration and recovery of rare earth elements (REEs) from low-concentration solution, due to its superior removal efficiency for REEs and environmental friendliness. However, the nanoparticles also cause some severe problems during application, including aggregation, blockage in fixed-bed column, as well as the difficulties in separation and reuse. Herein, in order to avoid the mentioned problems, a carbon cloth (CC) supported nano-Mg(OH)2 (nano-Mg(OH)2@CC) was synthesized by electrodeposition. The X-ray diffraction and scanning electron microscopy analysis demonstrated that the interlaced nano-sheet of Mg(OH)2 grew firmly and uniformly on the surface of carbon cloth fibers. Batch adsorption experiments of Eu(III) indicated that the nano-Mg(OH)2@CC composite maintained the excellent adsorption performance of nano-Mg(OH)2 toward Eu(III). After adsorption, the Eu containing composite was calcined under nitrogen atmosphere. The content of Eu2O3 in the calcined material was as high as 99.66%. Fixed-bed column experiments indicated that no blockage for Mg(OH)2@CC composite was observed during the treatment, while the complete blockage of occurred to nano-Mg(OH)2 at an effluent volume of 240 mL. Moreover, the removal efficiency of Mg(OH)2@CC was still higher than 90% until 4200 mL of effluent volume. This work provides a promising method for feasible application of nanoadsorbents in fixed-bed process to recycle low-concentration REEs from wastewater.

Carbon Cloth Supported Nano-Mg(OH)2 for the Enrichment and Recovery of Rare Earth Element Eu(III) From Aqueous Solution

PubMed Central

Li, Yinong; Tian, Chen; Liu, Weizhen; Xu, Si; Xu, Yunyun; Cui, Rongxin; Lin, Zhang

2018-01-01

Nano-Mg(OH)2 is attracting great attention as adsorbent for pre-concentration and recovery of rare earth elements (REEs) from low-concentration solution, due to its superior removal efficiency for REEs and environmental friendliness. However, the nanoparticles also cause some severe problems during application, including aggregation, blockage in fixed-bed column, as well as the difficulties in separation and reuse. Herein, in order to avoid the mentioned problems, a carbon cloth (CC) supported nano-Mg(OH)2 (nano-Mg(OH)2@CC) was synthesized by electrodeposition. The X-ray diffraction and scanning electron microscopy analysis demonstrated that the interlaced nano-sheet of Mg(OH)2 grew firmly and uniformly on the surface of carbon cloth fibers. Batch adsorption experiments of Eu(III) indicated that the nano-Mg(OH)2@CC composite maintained the excellent adsorption performance of nano-Mg(OH)2 toward Eu(III). After adsorption, the Eu containing composite was calcined under nitrogen atmosphere. The content of Eu2O3 in the calcined material was as high as 99.66%. Fixed-bed column experiments indicated that no blockage for Mg(OH)2@CC composite was observed during the treatment, while the complete blockage of occurred to nano-Mg(OH)2 at an effluent volume of 240 mL. Moreover, the removal efficiency of Mg(OH)2@CC was still higher than 90% until 4,200 mL of effluent volume. This work provides a promising method for feasible application of nanoadsorbents in fixed-bed process to recycle low-concentration REEs from wastewater. PMID:29721492

Method and apparatus for animal positioning in imaging systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hadjioannou, Arion-Xenofon; Stout, David B.; Silverman, Robert W.

An apparatus for imaging an animal includes a first mounting surface, a bed sized to support the animal and releasably secured to or integral with the first mounting surface. The apparatus also includes a plurality of straps, each having a first end in a fixed position relative to the bed and a second end for tightening around a limb of the animal. A method for in-vivo imaging of an animal includes providing an animal that has limbs, providing a first mounting surface, and providing a bed removably secured to or integral with the mounting surface and sized to support themore » animal as well as being coupled to a plurality of straps. The method also includes placing the animal on the bed between the plurality of straps and tightening at least two of the plurality of straps around at least two of the limbs such that the animal is substantially secured in place relative to the bed.« less

9 CFR 3.3 - Sheltered housing facilities.

Code of Federal Regulations, 2012 CFR

2012-01-01

... attending veterinarian. Dry bedding, solid resting boards, or other methods of conserving body heat must be... wire, wood, metal, or concrete; and (iii) All walls, boxes, houses, dens, and other surfaces in contact...

9 CFR 3.3 - Sheltered housing facilities.

Code of Federal Regulations, 2013 CFR

2013-01-01

... attending veterinarian. Dry bedding, solid resting boards, or other methods of conserving body heat must be... wire, wood, metal, or concrete; and (iii) All walls, boxes, houses, dens, and other surfaces in contact...

9 CFR 3.3 - Sheltered housing facilities.

Code of Federal Regulations, 2014 CFR

2014-01-01

... attending veterinarian. Dry bedding, solid resting boards, or other methods of conserving body heat must be... wire, wood, metal, or concrete; and (iii) All walls, boxes, houses, dens, and other surfaces in contact...

Phyto-dewatering of sewage sludge using Panicum repens L.

PubMed

El-Gendy, A S; El-Kassas, H I; Razek, T M A; Abdel-Latif, H

2017-04-01

Experiments in the field environment have been conducted to study the growth of Panicum repens L., an aquatic plant, in the sewage sludge matrix. The experiments were also carried out to investigate the ability of this plant to dewater sewage sludge to increase the capacity of conventional drying beds. In addition, the ability of Panicum repens L. to reduce the sludge contents of certain elements (copper (Cu), Iron (Fe), Sodium (Na), lead (Pb), and Zinc (Zn)) was also investigated. All experiments were carried out in batch reactors. Different plant coverage densities were tested (0.00 to 27.3 kg/m 2 ). The liquid sewage sludge was collected from a wastewater treatment plant in Helwan city, Cairo Governorate, Egypt. The collected sludge represents a mixture of the primary sludge and waste activated sludge before discharging into drying beds.

Sap fluxes from different parts of the rootzone modulate xylem ABA concentration during partial rootzone drying and re-wetting

PubMed Central

Pérez-Pérez, J. G.; Dodd, I. C.

2015-01-01

Previous studies with partial rootzone drying (PRD) irrigation demonstrated that alternating the wet and dry parts of the rootzone (PRD-Alternated) increased leaf xylem ABA concentration ([X-ABA]leaf) compared with maintaining the same wet and dry parts of the rootzone (PRD-Fixed). To determine the relative contributions of different parts of the rootzone to this ABA signal, [X-ABA]leaf of potted, split-root tomato (Solanum lycopersicum) plants was modelled by quantifying the proportional water uptake from different soil compartments, and [X-ABA]leaf responses to the entire pot soil-water content (θpot). Continuously measuring soil-moisture depletion by, or sap fluxes from, different parts of the root system revealed that water uptake rapidly declined (within hours) after withholding water from part of the rootzone, but was rapidly restored (within minutes) upon re-watering. Two hours after re-watering part of the rootzone, [X-ABA]leaf was equally well predicted according to θpot alone and by accounting for the proportional water uptake from different parts of the rootzone. Six hours after re-watering part of the rootzone, water uptake by roots in drying soil was minimal and, instead, occurred mainly from the newly irrigated part of the rootzone, thus [X-ABA]leaf was best predicted by accounting for the proportional water uptake from different parts of the rootzone. Contrary to previous results, alternating the wet and dry parts of the rootzone did not enhance [X-ABA]leaf compared with PRD-Fixed irrigation. Further work is required to establish whether altered root-to-shoot ABA signalling contributes to the improved yields of crops grown with alternate, rather than fixed, PRD. PMID:25740924

Sap fluxes from different parts of the rootzone modulate xylem ABA concentration during partial rootzone drying and re-wetting.

PubMed

Pérez-Pérez, J G; Dodd, I C

2015-04-01

Previous studies with partial rootzone drying (PRD) irrigation demonstrated that alternating the wet and dry parts of the rootzone (PRD-Alternated) increased leaf xylem ABA concentration ([X-ABA]leaf) compared with maintaining the same wet and dry parts of the rootzone (PRD-Fixed). To determine the relative contributions of different parts of the rootzone to this ABA signal, [X-ABA]leaf of potted, split-root tomato (Solanum lycopersicum) plants was modelled by quantifying the proportional water uptake from different soil compartments, and [X-ABA]leaf responses to the entire pot soil-water content (θpot). Continuously measuring soil-moisture depletion by, or sap fluxes from, different parts of the root system revealed that water uptake rapidly declined (within hours) after withholding water from part of the rootzone, but was rapidly restored (within minutes) upon re-watering. Two hours after re-watering part of the rootzone, [X-ABA]leaf was equally well predicted according to θpot alone and by accounting for the proportional water uptake from different parts of the rootzone. Six hours after re-watering part of the rootzone, water uptake by roots in drying soil was minimal and, instead, occurred mainly from the newly irrigated part of the rootzone, thus [X-ABA]leaf was best predicted by accounting for the proportional water uptake from different parts of the rootzone. Contrary to previous results, alternating the wet and dry parts of the rootzone did not enhance [X-ABA]leaf compared with PRD-Fixed irrigation. Further work is required to establish whether altered root-to-shoot ABA signalling contributes to the improved yields of crops grown with alternate, rather than fixed, PRD. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

Adsorption of Hg(II) and Pb(II) ions by nanoscale zero valent iron supported on ostrich bone ash in a fixed-bed column system.

PubMed

Amiri, Mohammad Javad; Abedi-Koupai, Jahangir; Eslamian, Saeid

2017-07-01

In this research, ostrich bone ash (OBA) was modified with nanoscale zerovalent iron (nZVI) particles and applied as a novel composite adsorbent (OBA/nZVI) for dynamic adsorption/reduction of Hg(II) and Pb(II) ions in a fixed-bed column system. Entrapment of nZVI in OBA beads barricades the particles from oxidation and aggregation. The dynamic behavior of metal ions removal by OBA/nZVI was assessed as a function of inlet flow rates, bed height, initial pollutants concentration and pH. The synthesized OBA/nZVI composite was characterized by several physicochemical techniques. Increase in pH and bed height and decrease in flow rates and initial metal concentration resulted in delay of breakthrough time. OBA breakthrough profile is sharper than the OBA/nZVI breakthrough curve for both metal ions and the breakthrough times increase in the order OBA/nZVI-Hg(II) > OBA/nZVI-Pb(II) > OBA-Pb(II) > OBA-Hg(II). Based on the experiment results, redox reaction is expected to occur to a certain extent, as the standard reduction potentials of Hg(II) and Pb(II) are more than that of Fe(II). From a practical point of view, the OBA/nZVI could be applied as a material to remove Hg(II) and Pb(II) ions from natural surface and ground water with a pH value of 5-9.

Fluoride removal from water using a magnesia-pullulan composite in a continuous fixed-bed column.

PubMed

Ye, Yuanyao; Yang, Jing; Jiang, Wei; Kang, Jianxiong; Hu, Ying; Ngo, Huu Hao; Guo, Wenshan; Liu, Yiwen

2018-01-15

A magnesia-pullulan composite (MgOP) was previously shown to effectively remove fluoride from water. In the present study, a continuous fixed-bed column was used to examine the application of the composite at an industrial scale. The influencing parameters included bed mass (4.0, 6.0 and 8.0 g), influent flow rate (8, 16 and 32 mL/min), inlet fluoride concentration (5, 10 and 20 mg/L), reaction temperature (20, 30 and 40 °C), influent pH (4, 7 and 10) and other existing anions (HCO 3 - , SO 4 2- , Cl - and NO 3 - ), through which the breakthrough curves could be depicted for the experimental data analysis. The results indicated that MgOP is promising for fluoride removal with a defluoridation capacity of 16.6 mg/g at the bed mass of 6.0 g, influent flow rate of 16 mL/min and inlet fluoride concentration of 10 mg/L. The dynamics of the fluoride adsorption process were modeled using the Thomas and Yan models, in which the Yan model presented better predictions for the breakthrough curves than the Thomas model. Moreover, the concentration of magnesium in the effluent was monitored to determine Mg stability in the MgOP composite. Results indicated the effluent concentration of Mg 2+ ions could be kept at a safe level. Calcination of fluoride-loaded MgOP effectively regenerated the material. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lateral Erosion Encourages Vertical Incision in a Bimodal Alluvial River

NASA Astrophysics Data System (ADS)

Gran, K. B.

2015-12-01

Sand can have a strong impact on gravel transport, increasing gravel transport rates by orders of magnitude as sand content increases. Recent experimental work by others indicates that adding sand to an armored bed can even cause armor to break-up and mobilize. These two elements together help explain observations from a bimodal sand and gravel-bedded river, where lateral migration into sand-rich alluvium breaks up the armor layer, encouraging further incision into the bed. Detailed bedload measurements were coupled with surface and subsurface grain size analyses and cross-sectional surveys in a seasonally-incised channel carved into the upper alluvial fan of the Pasig-Potrero River at Mount Pinatubo, Philippines. Pinatubo erupted in 1991, filling valleys draining the flanks of the volcano with primarily sand-sized pyroclastic flow debris. Twenty years after the eruption, sand-rich sediment inputs are strongly seasonal, with most sediment input to the channel during the rainy season. During the dry season, flow condenses from a wide braided planform to a single-thread channel in most of the upper basin, extending several km onto the alluvial fan. This change in planform creates similar unit discharge ranges in summer and winter. Lower sediment loads in the dry season drive vertical incision until the bed is sufficiently armored. Incision proceeds downstream in a wave, with increasing sediment transport rates and decreasing grain size with distance downstream, eventually reaching a gravel-sand transition and return to a braided planform. Incision depths in the gravel-bedded section exceeded 3 meters in parts of a 4 km-long study reach, a depth too great to be explained by predictions from simple winnowing during incision. Instead, lateral migration into sand-rich alluvium provides sufficient fine sediment to break up the armor surface, allowing incision to start anew and increasing the total depth of the seasonally-incised valley. Lateral migration is recorded in a series of inset terraces within the valley. The importance of sand on channel behavior thus extends beyond transport rates, affecting the depth of incision and volume of material excavated during a rainy to dry season transition.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buitrago, Paula A.; Morrill, Mike; Lighty, JoAnn S.

This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO 2, and halogen species were introduced through the burner to produce a radical pool representativemore » of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO 2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO 2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO 2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO 2, and NO 2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and intraparticle diffusion. The Freundlich isotherm more accurately described in-flight mercury capture. Using these parameters, very little intraparticle diffusion was evident. Consistent with other data, smaller particles resulted in higher mercury uptake due to available surface area. Therefore, it is important to capture the particle size distribution in the model. At typical full-scale sorbent feed rates, the calculations under-predicted adsorption, suggesting that wall effects can account for as much as 50 percent of the removal, making it an important factor in entrained-mercury adsorption models.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Buitrago, Paula A.; Morrill, Mike; Lighty, JoAnn S.

This report presents experimental and modeling mercury oxidation and adsorption data. Fixed-bed and single-particle models of mercury adsorption were developed. The experimental data were obtained with two reactors: a 300-W, methane-fired, tubular, quartz-lined reactor for studying homogeneous oxidation reactions and a fixed-bed reactor, also of quartz, for studying heterogeneous reactions. The latter was attached to the exit of the former to provide realistic combustion gases. The fixed-bed reactor contained one gram of coconut-shell carbon and remained at a temperature of 150°C. All methane, air, SO 2, and halogen species were introduced through the burner to produce a radical pool representativemore » of real combustion systems. A Tekran 2537A Analyzer coupled with a wet conditioning system provided speciated mercury concentrations. At 150°C and in the absence of HCl or HBr, the mercury uptake was about 20%. The addition of 50 ppm HCl caused complete capture of all elemental and oxidized mercury species. In the absence of halogens, SO 2 increased the mercury adsorption efficiency to up to 30 percent. The extent of adsorption decreased with increasing SO 2 concentration when halogens were present. Increasing the HCl concentration to 100 ppm lessened the effect of SO 2. The fixed-bed model incorporates Langmuir adsorption kinetics and was developed to predict adsorption of elemental mercury and the effect of multiple flue gas components. This model neglects intraparticle diffusional resistances and is only applicable to pulverized carbon sorbents. It roughly describes experimental data from the literature. The current version includes the ability to account for competitive adsorption between mercury, SO 2, and NO 2. The single particle model simulates in-flight sorbent capture of elemental mercury. This model was developed to include Langmuir and Freundlich isotherms, rate equations, sorbent feed rate, and intraparticle diffusion. The Freundlich isotherm more accurately described in-flight mercury capture. Using these parameters, very little intraparticle diffusion was evident. Consistent with other data, smaller particles resulted in higher mercury uptake due to available surface area. Therefore, it is important to capture the particle size distribution in the model. At typical full-scale sorbent feed rates, the calculations underpredicted adsorption, suggesting that wall effects can account for as much as 50 percent of the removal, making it an important factor in entrained-mercury adsorption models.« less

Fluidised-bed spray-drying formulations of Candida sake CPA-1 by adding biodegradable coatings to enhance their survival under stress conditions.

PubMed

Carbó, Anna; Torres, Rosario; Usall, Josep; Solsona, Cristina; Teixidó, Neus

2017-11-01

The biocontrol agent Candida sake CPA-1 has demonstrated to be effective against several diseases on fruit. However, for application of CPA-1 under field conditions, it was necessary to mix it with a food coating to improve survival under stress conditions, as well as adherence and distribution on fruit surfaces. The objective of this study was to obtain a more competitive formulation under field conditions to be applied independently of any product. To achieve this purpose, the drying process of CPA-1 by a fluidised-bed spray-drying system together with biodegradable coatings was optimised. This approach is novel for the drying system used and the formulation obtained which was able to form a film or coating on fruit surfaces. Several substances were tested as carriers and binders, and drying temperature was optimised. The addition of protective compounds was also tested to improve survival of CPA-1 during the dehydration process. Product shelf life, biocontrol efficacy on grapes against Botrytis cinerea, and the improvement of C. sake behaviour under stress conditions were tested. The optimal temperature of drying was 55 °C and two formulations that were able to develop a coating on fruit surfaces were obtained. One of the formulations was created by using a combination of native and pregelatinised potato starch; the other formulation was obtained using maltodextrin and by adding skimmed milk and sucrose as protectant compounds. The formulated products reduced the incidence and severity of B. cinerea, and CPA-1 survival rate was increased under stress conditions of temperature and humidity.

Medicaid Bed-Hold Policy and Medicare Skilled Nursing Facility Rehospitalizations

PubMed Central

Grabowski, David C; Feng, Zhanlian; Intrator, Orna; Mor, Vincent

2010-01-01

Objective To analyze the effect of states' Medicaid bed-hold policies on the 30-day rehospitalization of Medicare postacute skilled nursing facility (SNF) residents. Data Sources Minimum data set assessments were merged with Medicare claims and eligibility files for all first-time SNF admissions (N = 3,322,088) over the period 2000 through 2005; states' Medicaid bed-hold policies were obtained via survey. Study Design Regression specification incorporating facility fixed effects to examine changes in Medicaid bed-hold policies on the likelihood of a 30-day SNF rehospitalization. Principal Findings Using a continuous measure of bed-hold generosity, state Medicaid bed-hold was positively related to Medicare SNF rehospitalization. Specifically, the introduction of a bed-hold policy with average generosity increases Medicare rehospitalizations by 1.8 percent, representing roughly 12,000 SNF rehospitalizations at a cost to Medicare of approximately U.S.$100 million over our study period. Conclusions Although facilities do not receive a Medicaid bed-hold payment for Medicare SNF stays, we found that the adoption of more generous policies led to greater SNF rehospitalizations. This type of spillover is largely ignored in current discussions of Medicare payment reforms such as bundled payment. Neither Medicare nor Medicaid has an incentive to internalize the risks and benefits of its actions as they affect the other. PMID:20403059

77 FR 64588 - Highway Safety Programs; Conforming Products List of Calibrating Units for Breath Alcohol Testers

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-22

... accuracy and precision for wet bath and dry gas calibrating units using infra-red spectroscopy. On June 25... infra-red spectroscopy (72 FR 34742). That notice also adds references to the dry gas standards by fixed...

Odorous Volatile Organic Compounds, Escherichia coli, and Nutrient Concentrations when Kiln-Dried Pine Chips and Corn Stover Bedding Are Used in Beef Bedded Manure Packs.

PubMed

Spiehs, Mindy J; Berry, Elaine D; Wells, James E; Parker, David B; Brown-Brandl, Tami M

2017-07-01

Pine ( spp.) bedding has been shown to lower the concentration of odorous volatile organic compounds (VOCs) and pathogenic bacteria compared with corn ( L.) stover bedding, but availability and cost limit the use of pine bedding in cattle confinement facilities. The objectives of this study were to determine if the addition of pine wood chips to laboratory-scaled bedded packs containing corn stover (i) reduced odorous VOC emissions; (ii) reduced total ; and (iii) changed the nutrient composition of the resulting manure-bedded packs. Bedding treatments included 0, 10, 20, 30, 40, 60, 80, and 100% pine chips, with the balance being corn stover. Four bedded packs for each mixture were maintained for 42 d ( = 4 observations per bedding material). The production of total sulfur compounds increased significantly when 100% pine chips were used (44.72 ng L) compared with bedding mixture containing corn stover (18.0-24.56 ng L). The carbon-to-nitrogen ratio exceeded the ideal ratio of 24:1 for the optimum activity of soil microorganisms when ≥60% pine chips (25.3-27.5 ng L) were included in the mixture. The use of 100% pine chips as bedding increased sulfide concentration in the facility 1.8 to 2.4 times over the use of corn stover bedding. was not influenced by the addition of pine chips to the corn stover bedding material but did decrease as the bedded pack aged. Bedding material mixtures containing 30 to 60% pine and 40 to 70% corn stover may be the ideal combination to mitigate odors from livestock facilities using deep bedded systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Experimental simulation of gravity currents in erodible bed

NASA Astrophysics Data System (ADS)

Bateman, A.; La Roca, M.; Medina, V.

2009-04-01

Gravity currents are commonly met in nature, when a flow of denser fluid moves into a less dense one. A typical example of a gravity current is given by the sea water which flows into the bottom of a river during the summer, in correspondence of the estuary, when the river's discharge attains low values. In this case, dangerous consequences can occur, because of the polluting of the aquifer caused by the salty water. Density currents also occurs in lakes and reservoirs, because of a change in temperature or because a flood, both can produce some environmental impacts that are of interest to the local water Agency of the different countries. Of particular relevance is also the interaction of the gravity current with the movement of the sediments from the bottom of the bed. The international state of the art is particularly concerned with experimental and numerical investigation on gravity currents on fixed and porous bed [1-2-3], while, to the authors' knowledge, the interaction of a gravity current with an erodible bed is still an open field of investigation. In this paper experiments concerning with the propagation of a gravity current over fixed and erodible bed are presented. The experiments, conducted at the laboratory of Hydraulics of the Universitat Politecnica de Catalunya (actually in the Prof. Bateman's blue room), were concerned with a transparent tank 2 m long, 0.2 m wide and 0.3 m deep, partly filled with salty water and partly with fresh water, up to a depth of 0.28 m. The salty water, whose density was in the range 1050

Influence of factors on the drying of cassava in a solar simulator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Njie, D.N.; Rumsey, T.R.

1997-03-01

In tropical countries, sun drying is still the most popular method used for processing root and tuber crops like cassava and yam. Relatively very little has been done on studying the kinetics of sun drying a bed of chips of cassava and similar crops, but this information is invaluable in finding options for reducing drying time and costs, and increasing tonnage produced. This project studied some factors that have an effect on the sun drying rate of cassava chips. The factors were ambient temperature, relative humidity, radiation intensity, air velocity, and loading density. A solar simulation chamber was constructed somore » that drying could be achieved under controllable conditions similar to those obtained in sun drying. Experiments carried out in the simulator revealed that temperature had the most significant effect on drying rate, followed by air velocity, and radiation intensity. Regression equations were developed relating the drying rate with the factors studied.« less

Litter Species Composition and Topographic Effects on Fuels and Modeled Fire Behavior in an Oak-Hickory Forest in the Eastern USA

PubMed Central

Hutchinson, Todd F.; Dietenberger, Mark; Matt, Frederick; Peters, Matthew P.

2016-01-01

Mesophytic species (esp. Acer rubrum) are increasingly replacing oaks (Quercus spp.) in fire-suppressed, deciduous oak-hickory forests of the eastern US. A pivotal hypothesis is that fuel beds derived from mesophytic litter are less likely than beds derived from oak litter to carry a fire and, if they do, are more likely to burn at lower intensities. Species effects, however, are confounded by topographic gradients that affect overstory composition and fuel bed decomposition. To examine the separate and combined effects of litter species composition and topography on surface fuel beds, we conducted a common garden experiment in oak-hickory forests of the Ohio Hills. Each common garden included beds composed of mostly oak and mostly maple litter, representative of oak- and maple-dominated stands, respectively, and a mixture of the two. Beds were replenished each fall for four years. Common gardens (N = 16) were established at four topographic positions (ridges, benches on south- and northeast-facing slopes, and stream terraces) at each of four sites. Litter source and topographic position had largely independent effects on fuel beds and modeled fire dynamics after four years of development. Loading (kg m-2) of the upper litter layer (L), the layer that primarily supports flaming spread, was least in more mesic landscape positions and for maple beds, implying greater decomposition rates for those situations. Bulk density in the L layer (kg m-3) was least for oak beds which, along with higher loading, would promote fire spread and fireline intensity. Loading and bulk density of the combined fermentation and humic (FH) layers were least on stream terrace positions but were not related to species. Litter- and FH-layer moistures during a 5-day dry-down period after a rain event were affected by time and topographic effects while litter source effects were not evident. Characteristics of flaming combustion determined with a cone calorimeter pointed to greater fireline intensity for oak fuel beds and unexpected interactions between litter source and topography. A spread index, which synthesizes a suite of fuel bed, particle, and combustion characteristics to indicate spread (vs extinction) potential, was primarily affected by litter source and, secondarily, by the low spread potentials on mesic landscape positions early in the 5-day dry-down period. A similar result was obtained for modeled fireline intensity. Our results suggest that the continuing transition from oaks to mesophytic species in the Ohio Hills will reduce fire spread potentials and fire intensities. PMID:27536964

Litter Species Composition and Topographic Effects on Fuels and Modeled Fire Behavior in an Oak-Hickory Forest in the Eastern USA.

PubMed

Dickinson, Matthew B; Hutchinson, Todd F; Dietenberger, Mark; Matt, Frederick; Peters, Matthew P

2016-01-01

Mesophytic species (esp. Acer rubrum) are increasingly replacing oaks (Quercus spp.) in fire-suppressed, deciduous oak-hickory forests of the eastern US. A pivotal hypothesis is that fuel beds derived from mesophytic litter are less likely than beds derived from oak litter to carry a fire and, if they do, are more likely to burn at lower intensities. Species effects, however, are confounded by topographic gradients that affect overstory composition and fuel bed decomposition. To examine the separate and combined effects of litter species composition and topography on surface fuel beds, we conducted a common garden experiment in oak-hickory forests of the Ohio Hills. Each common garden included beds composed of mostly oak and mostly maple litter, representative of oak- and maple-dominated stands, respectively, and a mixture of the two. Beds were replenished each fall for four years. Common gardens (N = 16) were established at four topographic positions (ridges, benches on south- and northeast-facing slopes, and stream terraces) at each of four sites. Litter source and topographic position had largely independent effects on fuel beds and modeled fire dynamics after four years of development. Loading (kg m-2) of the upper litter layer (L), the layer that primarily supports flaming spread, was least in more mesic landscape positions and for maple beds, implying greater decomposition rates for those situations. Bulk density in the L layer (kg m-3) was least for oak beds which, along with higher loading, would promote fire spread and fireline intensity. Loading and bulk density of the combined fermentation and humic (FH) layers were least on stream terrace positions but were not related to species. Litter- and FH-layer moistures during a 5-day dry-down period after a rain event were affected by time and topographic effects while litter source effects were not evident. Characteristics of flaming combustion determined with a cone calorimeter pointed to greater fireline intensity for oak fuel beds and unexpected interactions between litter source and topography. A spread index, which synthesizes a suite of fuel bed, particle, and combustion characteristics to indicate spread (vs extinction) potential, was primarily affected by litter source and, secondarily, by the low spread potentials on mesic landscape positions early in the 5-day dry-down period. A similar result was obtained for modeled fireline intensity. Our results suggest that the continuing transition from oaks to mesophytic species in the Ohio Hills will reduce fire spread potentials and fire intensities.

Budesonide + formoterol fumarate dihydrate for the treatment of asthma.

PubMed

Wolthers, Ole D

2016-01-01

One of the most widely used fixed combinations in asthma management is dry powder budesonide+formoterol fumarate dihydrate which is commercially available as Symbicort Turbuhaler(®) (and generic products), Easyhaler Bufomix(®) and DuoRespSpiromax(®) inhaler. The aim of this paper was to review the fixed dry powder combination of inhaled budesonide+formoterol fumarate dihydrate for asthma treatment in adolescents and adults. A literature search using relevant search terms, reference lists for reviews and meta-analyses was performed. In symptomatic adolescent and adult patients with asthma maintenance and reliever therapy with a single-inhaler fixed combination of dry powder budesonide+formoterol fumarate dihydrate is an evidenced option. The combination treatment is convenient to patients. It reduces the number of exacerbations requiring treatment with oral corticosteroids. In some patients the strategy may also reduce the total intake of inhaled corticosteroids over time. Whether important outcome measures of asthma treatment, such as hospital admission and emergency room visit rates, may be reduced is less well documented since the published studies may have been influenced by publication bias. Non-pharmaceutical company-sponsored research evaluating such measures is needed. There is no evidence for the use of single inhaler fixed combinations of inhaled corticosteroids+long-acting β(2)-agonists in children (<12 years of age), and budesonide+formoterol fumarate dihydrate should not be prescribed to the age group.

14. UPPER SHOES, FIXED SHOES, ROLLER SHOES, CENTER WEB, AND ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. UPPER SHOES, FIXED SHOES, ROLLER SHOES, CENTER WEB, AND ROLLER BED PLATES. (Also includes a sheet index and a schedule of parts). American Bridge Company, Ambridge Plant No. 5, sheet no. 4, dated April 7, 1928, order no. F5073. For U.S. Steel Products Company, Pacific Coast Depot, order no. SF578. For Southern Pacific Company, order no. 8873-P-28746. various scales. - Napa River Railroad Bridge, Spanning Napa River, east of Soscol Avenue, Napa, Napa County, CA

Use of soft hydrothermal processing to improve and recycle bedding for laboratory animals.

PubMed

Miyamoto, T; Li, Z; Kibushi, T; Yamasaki, N; Kasai, N

2008-10-01

Cage bedding for laboratory rodents can influence animal wellbeing and thus the experimental data. In addition, a large amount of used bedding containing excrement is discharged as medical waste from life science institutes and breeding companies. We developed a ground-breaking system to improve fresh bedding and recycle used bedding by applying a soft hydrothermal process with high-temperature and high-pressure dry steam. The system removes both harmful organic components and aromatic hydrocarbons that can affect animals' metabolism. The purpose of the present study was to evaluate the chemical and physical properties of the improved fresh bedding and the recycled used bedding treated by the system. The results showed that 68-99% of the predominant aromatic hydrocarbons were removed from fresh bedding treated at 0.35 MPa and 140 degrees C for 120 min ('improved bedding'). In addition, 59.4-99.0% of predominant harmful organic compounds derived from excrement were removed from used bedding treated at 0.45 MPa and 150 degrees C for 60 min ('recycled bedding'). The soft hydrothermal treatment increased the number of acidic functional groups on the bedding surface and gave it the high adsorptive efficiency of ammonia gas. Harmful substances such as microorganisms, heavy metals and pesticides decreased below the detection limit. The results clearly showed that the improved and recycled bedding is safer for laboratory rodents and has the potential to ameliorate conditions in primary and secondary enclosures (e.g. cages and animal rooms) used for maintaining laboratory animals. This process may be one of the most advanced techniques in providing an alternative to softwood and other bedding, economizing through the recycling of used bedding and reducing bedding waste from animal facilities.

A Monocular Vision Measurement System of Three-Degree-of-Freedom Air-Bearing Test-Bed Based on FCCSP

NASA Astrophysics Data System (ADS)

Gao, Zhanyu; Gu, Yingying; Lv, Yaoyu; Xu, Zhenbang; Wu, Qingwen

2018-06-01

A monocular vision-based pose measurement system is provided for real-time measurement of a three-degree-of-freedom (3-DOF) air-bearing test-bed. Firstly, a circular plane cooperative target is designed. An image of a target fixed on the test-bed is then acquired. Blob analysis-based image processing is used to detect the object circles on the target. A fast algorithm (FCCSP) based on pixel statistics is proposed to extract the centers of object circles. Finally, pose measurements can be obtained when combined with the centers and the coordinate transformation relation. Experiments show that the proposed method is fast, accurate, and robust enough to satisfy the requirement of the pose measurement.

Los Angeles, CA.

NASA Image and Video Library

1992-03-30

STS003-010-593 (30 March 1982) --- A general view of the greater Los Angeles region of California (34,0N, 118.5W) showing the coastline, Vandenberg AFB, the south end of the Central Valley and the dry lake beds at Edwards AFB. A close look can pinpoint water on the lake beds at Edwards Air Force Base used previously for two shuttle landings. Among other features that can be seen are Oxnard, Santa Barbara, Bakersfield, Vandenberg Air Force Base, and The Ranch. Photo credit: NASA

Performance Evaluation of Engineered Structured Sorbents for Atmosphere Revitalization Systems On Board Crewed Space Vehicles and Habitats

NASA Technical Reports Server (NTRS)

Howard, David F.; Perry, Jay L.; Knox, James C.; Junaedi, Christian; Roychoudhury, Subir

2011-01-01

Engineered structured (ES) sorbents are being developed to meet the technical challenges of future crewed space exploration missions. ES sorbents offer the inherent performance and safety attributes of zeolite and other physical adsorbents but with greater structural integrity and process control to improve durability and efficiency over packed beds. ES sorbent techniques that are explored include thermally linked and pressure-swing adsorption beds for water-save dehumidification and sorbent-coated metal meshes for residual drying, trace contaminant control, and carbon dioxide control. Results from sub-scale performance evaluations of a thermally linked pressure-swing adsorbent bed and an integrated sub-scale ES sorbent system are discussed.

Application of capillary gas chromatography mass spectrometry/computer techniques to synoptic survey of organic material in bed sediment

USGS Publications Warehouse

Steinheimer, T.R.; Pereira, W.E.; Johnson, S.M.

1981-01-01

A bed sediment sample taken from an area impacted by heavy industrial activity was analyzed for organic compounds of environmental significance. Extraction was effected on a Soxhlet apparatus using a freeze-dried sample. The Soxhlet extract was fractionated by silica gel micro-column adsorption chromatography. Separation and identification of the organic compounds was accomplished by capillary gas chromatography/mass spectrometry techniques. More than 50 compounds were identified; these include saturated hydrocarbons, olefins, aromatic hydrocarbons, alkylated polycyclic aromatic hydrocarbons, and oxygenated compounds such as aldehydes and ketones. The role of bed sediments as a source or sink for organic pollutants is discussed. ?? 1981.

Caribbean-wide, long-term study of seagrass beds reveals local variations, shifts in community structure and occasional collapse.

PubMed

van Tussenbroek, Brigitta I; Cortés, Jorge; Collin, Rachel; Fonseca, Ana C; Gayle, Peter M H; Guzmán, Hector M; Jácome, Gabriel E; Juman, Rahanna; Koltes, Karen H; Oxenford, Hazel A; Rodríguez-Ramirez, Alberto; Samper-Villarreal, Jimena; Smith, Struan R; Tschirky, John J; Weil, Ernesto

2014-01-01

The CARICOMP monitoring network gathered standardized data from 52 seagrass sampling stations at 22 sites (mostly Thalassia testudinum-dominated beds in reef systems) across the Wider Caribbean twice a year over the period 1993 to 2007 (and in some cases up to 2012). Wide variations in community total biomass (285 to >2000 g dry m(-2)) and annual foliar productivity of the dominant seagrass T. testudinum (<200 and >2000 g dry m(-2)) were found among sites. Solar-cycle related intra-annual variations in T. testudinum leaf productivity were detected at latitudes > 16°N. Hurricanes had little to no long-term effects on these well-developed seagrass communities, except for 1 station, where the vegetation was lost by burial below ∼1 m sand. At two sites (5 stations), the seagrass beds collapsed due to excessive grazing by turtles or sea-urchins (the latter in combination with human impact and storms). The low-cost methods of this regional-scale monitoring program were sufficient to detect long-term shifts in the communities, and fifteen (43%) out of 35 long-term monitoring stations (at 17 sites) showed trends in seagrass communities consistent with expected changes under environmental deterioration.

Fluidised Bed Microencapsulation of Ascorbic Acid: Effectiveness of Protection under Simulated Tropical Storage Conditions

DTIC Science & Technology

2012-01-01

example, probiotics (Kailasapathy, 2002; Rokka and Rantamäki, 2010), folic acid (Madziva et al., 2006) and ascorbic acid (Wijaya et al., 2011...Kailasapathy, K. 2002. Microencapsulation of Probiotic Bacteria: Technology and Potential Applications. Current Issues in Intestinal Microbiology, 3: 39-48...Re´, M. I. 1998. Microencapsulation by spray drying. Drying Technology, 16:1195–1236. Rokka, S., and Rantamäki, P. 2010. Protecting probiotic

Method and apparatus for chemically altering fluids in continuous flow

DOEpatents

Heath, W.O.; Virden, J.W. Jr.; Richardson, R.L.; Bergsman, T.M.

1993-10-19

The present invention relates to a continuous flow fluid reactor for chemically altering fluids. The reactor operates on standard frequency (50 to 60 Hz) electricity. The fluid reactor contains particles that are energized by the electricity to form a corona throughout the volume of the reactor and subsequently a non-equilibrium plasma that interacts with the fluid. Particles may form a fixed bed or a fluid bed. Electricity may be provided through electrodes or through an inductive coil. Fluids include gases containing exhaust products and organic fuels requiring oxidation. 4 figures.

Method and apparatus for chemically altering fluids in continuous flow

DOEpatents

Heath, William O.; Virden, Jr., Judson W.; Richardson, R. L.; Bergsman, Theresa M.

1993-01-01

The present invention relates to a continuous flow fluid reactor for chemically altering fluids. The reactor operates on standard frequency (50 to 60 Hz) electricity. The fluid reactor contains particles that are energized by the electricity to form a corona throughout the volume of the reactor and subsequently a non-equilibrium plasma that interacts with the fluid. Particles may form a fixed bed or a fluid bed. Electricity may be provided through electrodes or through an inductive coil. Fluids include gases containing exhaust products and organic fuels requiring oxidation.

Coarse-grained discrete particle simulations of particle segregation in rotating fluidized beds in vortex chambers [Discrete particle simulations of particle segregation in rotating fluidized beds in vortex chambers

DOE PAGES

Verma, Vikrant; Li, Tingwen; De Wilde, Juray

2017-05-26

Vortex chambers allow the generation of rotating fluidized beds, offering high-G intensified gas-solid contact, gas-solids separation and solids-solids segregation. Focusing on binary particle mixtures and fixing the density and diameter of the heavy/large particles, transient batch CFD-coarse-grained DPM simulations were carried out with varying densities or sizes of the light/small particles to evaluate to what extent combining these three functionalities is possible within a vortex chamber of given design. Both the rate and quality of segregation were analyzed. Within a relatively wide density and size range, fast and efficient segregation takes place, with an inner and slower rotating bed ofmore » the lighter/small particles forming within the outer and faster rotating bed of the heavier/large particles. Simulations show that the contamination of the outer bed with lighter particles occurs more easily than contamination of the inner bed with heavier particles and increases with decreasing difference in size or density of the particles. Bubbling in the inner bed is observed with an inner bed of very low density or small particles. Porosity plots show that vortex chambers with a sufficient number of gas inlet slots have to be used to guarantee a uniform gas distribution and particle bed. Lastly, the flexibility of particle segregation in vortex chambers with respect to the gas flow rate is demonstrated.« less

Coarse-grained discrete particle simulations of particle segregation in rotating fluidized beds in vortex chambers [Discrete particle simulations of particle segregation in rotating fluidized beds in vortex chambers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verma, Vikrant; Li, Tingwen; De Wilde, Juray

Vortex chambers allow the generation of rotating fluidized beds, offering high-G intensified gas-solid contact, gas-solids separation and solids-solids segregation. Focusing on binary particle mixtures and fixing the density and diameter of the heavy/large particles, transient batch CFD-coarse-grained DPM simulations were carried out with varying densities or sizes of the light/small particles to evaluate to what extent combining these three functionalities is possible within a vortex chamber of given design. Both the rate and quality of segregation were analyzed. Within a relatively wide density and size range, fast and efficient segregation takes place, with an inner and slower rotating bed ofmore » the lighter/small particles forming within the outer and faster rotating bed of the heavier/large particles. Simulations show that the contamination of the outer bed with lighter particles occurs more easily than contamination of the inner bed with heavier particles and increases with decreasing difference in size or density of the particles. Bubbling in the inner bed is observed with an inner bed of very low density or small particles. Porosity plots show that vortex chambers with a sufficient number of gas inlet slots have to be used to guarantee a uniform gas distribution and particle bed. Lastly, the flexibility of particle segregation in vortex chambers with respect to the gas flow rate is demonstrated.« less

Occurrence of pesticides in surface water and sediments from three central California coastal watersheds, 2008-2009

USGS Publications Warehouse

Smalling, Kelly L.; Orlando, James L.

2011-01-01

Water and sediment (bed and suspended) were collected from January 2008 through October 2009 from 12 sites in 3 of the largest watersheds along California's Central Coast (Pajaro, Salinas, and Santa Maria Rivers) and analyzed for a suite of pesticides by the U.S. Geological Survey. Water samples were collected in each watershed from the estuaries and major tributaries during 4 storm events and 11 dry season sampling events in 2008 and 2009. Bed sediments were collected from depositional zones at the tributary sampling sites three times over the course of the study. Suspended sediment samples were collected from the major tributaries during the four storm events and in the tributaries and estuaries during three dry season sampling events in 2009. Water samples were analyzed for 68 pesticides using gas chromatography/mass spectrometry. A total of 38 pesticides were detected in 144 water samples, and 13 pesticides were detected in more than half the samples collected over the course of the study. Dissolved pesticide concentrations ranged from below their method detection limits to 36,000 nanograms per liter (boscalid). The most frequently detected pesticides in water from all the watersheds were azoxystrobin, boscalid, chlorpyrifos, DCPA, diazinon, oxyfluorfen, prometryn, and propyzamide, which were found in more than 80 percent of the samples. On average, detection frequencies and concentrations were higher in samples collected during winter storm events compared to the summer dry season. With the exception of the fungicide, myclobutanil, the Santa Maria estuary watershed exhibited higher pesticide detection frequencies than the Pajaro and Salinas watersheds. Bed and suspended sediment samples were analyzed for 55 pesticides using accelerated solvent extraction, gel permeation chromatography for sulfur removal, and carbon/alumina stacked solid-phase extraction cartridges to remove interfering sediment matrices. In bed sediment samples, 17 pesticides were detected including pyrethroid and organophosphate (OP) insecticides, p,p'-DDT and its degradates, as well as several herbicides. The only pesticides detected more than half the time were p,p'-DDD, p,p'-DDE, and p,p'-DDT. Maximum pesticide concentrations ranged from less than their respective method detection limits to 234 micrograms per kilogram (p,p'-DDE). Four pyrethroids (bifenthrin, &# 955;-cyhalothrin, permethrin, and &# 964;-fluvalinate) were detected in bed sediment samples, though concentrations were relatively low (less than 10 microgram per kilogram). The greatest number of pesticides were detected in samples collected from Lower Orcutt Creek, the major tributary to the Santa Maria estuary. In suspended sediment samples, 19 pesticides were detected, and maximum concentrations ranged from less than the method detection limits to 549 micrograms per kilogram (chlorpyrifos). The most frequently detected pesticides were p,p'-DDE (49 percent), p,p'-DDT (38 percent), and chlorpyrifos (32 percent). During storm events, 19 pesticides were detected in suspended sediment samples compared to 10 detected during the dry season. Pesticide concentrations commonly were higher in suspended sediments during storm events than during the dry season, as well.

Effects of sorbent attrition on utilization. Final report, June 1, 1990--June 30, 1991

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keener, T.C.; Khang, Soon-Jai; Lee, S.K.

1992-03-01

Attrition of surface product levers of sulfite/sulfate may be the key to substantially increasing sorbent utilization in new dry scrubbing processes. This conclusion has been reached from research results obtained from new gas/solid contacting methods such as the Circulating Fluidized Bed Absorber and the Limestone Emission Control method. An additional savings may be reduced by the use of large initial sorbent, particle sizes which greatly reduces the cost of grinding and sorbent preparation. The objectives of project 1.7 were then to study attrition of sorbent particles in a systematic fashion in order to determine how to use attrition to increasemore » sorbent utilization. This was to be carried out by the construction of a bench scale fluidized bed where a series of experiments were to be conducted to measure attrition of lime and limestone samples. This has been accomplished and the project proceeded as anticipated. The results indicate that attrition differs for wet and dry conditions for certain sorbents and that these differences are substantial. Under dry conditions, the results of attrition tests on carefully characterized lime samples indicate that mechanical abrasion is the primary attrition mechanism. The rate of attrition is seen to be similar to a first order chemical reaction where the bed mass (or total surface area) is analagous to reactant concentration. A model for mechanical attrition is presented which expresses the rate constant in an Arrhenius type form proportional to a pseudo attrition activation energy and excess gas energy above a minimum level. The value of this pseudo attrition activation energy for lime has been found to be 106 KJ/KG. For the attrition of wetted lime particles in a fluidized bed. the attrition rate has been found to be directly related to the volumetric flow rate of injected water.« less

Experimental study on the effects of fixed boundaries in channelized free surface dry granular flows

NASA Astrophysics Data System (ADS)

Sarno, Luca; Carleo, Luigi; Nicolina Papa, Maria

2017-04-01

The dynamics of granular mixtures, involved in geophysical flows like avalanches and debris flows, is far from being completely understood. Several features of their motion, such as rheological stratification, non-local and boundary effects, still represent open problems. Experimental investigations at laboratory scale are an important tool that can provide insights about the dynamics of gravity driven granular flows. The measuring techniques should be non-invasive in order to measure undisturbed flows. In this work we present an experimental campaign devoted to the measurement of the velocity profiles of free surface steady granular flows in an open channel. To achieve this goal the flows were recorded by two cameras and velocity profiles were obtained by image analysis. The employed granular medium consists of acetal-polymeric beads with a mean diameter of 3mm and an estimated internal friction angle of 27°. All the experiments have been performed in a 2m-long plexiglas flume with a rectangular cross-section and a slope angle of 30°. The upper part of the channel was used as a reservoir where the material was loaded before each run and then let flow down through an adjustable gate. Several mass flow rates were investigated. Three different basal surfaces were employed so as to observe slip and non-slip boundary conditions: a smooth Bakelite surface, a roughened surface, obtained by gluing a layer of grains on the bed surface and a sandpaper surface with characteristic length of the roughness equal to 425 µm. The flume is equipped with two high-speed cameras, one placed aside the channel and the other one perpendicular to the channel bed, as to get both side-wall and free surface velocity profiles. The particle image velocimetry open-source code, PIVlab, is employed for estimating the flow velocities. All the free surface velocity profiles show an approximately parabolic shape with a maximum at the cross-section midpoint and a minimum at the side-walls, due to the wall friction. Different kinds of side-wall velocity profiles are observed. As regards the smooth basal surface, a slip velocity at the bed is observed. The profiles are Bagnold-type near the free surface and become linear as the depth increases. On the glued-grain basal surface the flow velocity at the bed is null and all the velocity profiles show a rheological stratification with a lower exponential tail and an upper linear profile. Grain rolling is observed at the sandpaper bed, instead. With the increase of flow depths, the velocity profiles gradually shift from the ones observed on the smooth bed to the ones observed on the glued-grain bed. In order to further understand the constitutive behaviour of granular mixtures, it is useful to perform simultaneous measurements of flow velocity and volume fraction. In this perspective, a new series of experiments is actually undergoing for the measurement of the volume fraction.

Adsorptive removal of heavy metals from water using sodium titanate nanofibres loaded onto GAC in fixed-bed columns.

PubMed

Sounthararajah, D P; Loganathan, P; Kandasamy, J; Vigneswaran, S

2015-04-28

Heavy metals are serious pollutants in aquatic environments. A study was undertaken to remove Cu, Cd, Ni, Pb and Zn individually (single metal system) and together (mixed metals system) from water by adsorption onto a sodium titanate nanofibrous material. Langmuir adsorption capacities (mg/g) at 10(-3)M NaNO3 ionic strength in the single metal system were 60, 83, 115 and 149 for Ni, Zn, Cu, and Cd, respectively, at pH 6.5 and 250 for Pb at pH 4.0. In the mixed metals system they decreased at high metals concentrations. In column experiments with 4% titanate material and 96% granular activated carbon (w/w) mixture at pH 5.0, the metals breakthrough times and adsorption capacities (for both single and mixed metals systems) decreased in the order Pb>Cd, Cu>Zn>Ni within 266 bed volumes. The amounts adsorbed were up to 82 times higher depending on the metal in the granular activated carbon+titanate column than in the granular activated carbon column. The study showed that the titanate material has high potential for removing heavy metals from polluted water when used with granular activated carbon at a very low proportion in fixed-bed columns. Copyright © 2015 Elsevier B.V. All rights reserved.

Skin hydration in nursing home residents using disposable bed baths.

PubMed

Gillis, Katrin; Tency, Inge; Roelant, Ella; Laureys, Sarina; Devriendt, Hendrik; Lips, Dirk

2016-01-01

The objective of this study was to evaluate a new way for applying bed baths and reducing the risk for dry skin by comparing the effect of two washing methods on skin hydration. A cluster randomized trial was conducted. Skin hydration was measured before and after implementation of disposable wash gloves, using a MoistureMeter SC at three skin sites. Total skin hydration did not differ between residents at the start of the study in both groups. After implementation, the post minus pre hydration scores were higher for the intervention group than the control group at all skin sites. However, the difference was only significant at cheek site. The use of disposable wash gloves does not increase the risk for dry skin in comparison with traditional washing methods. These results may encourage the introduction of disposable wash gloves as an innovation in daily skin care practice. Copyright © 2016 Elsevier Inc. All rights reserved.

Hydrodeoxygenation and coupling of aqueous phenolics over bifunctional zeolite-supported metal catalysts.

PubMed

Hong, Do-Young; Miller, Stephen J; Agrawal, Pradeep K; Jones, Christopher W

2010-02-21

Pt supported on HY zeolite is successfully used as a bifunctional catalyst for phenol hydrodeoxygenation in a fixed-bed configuration at elevated hydrogen pressures, leading to hydrogenation-hydrogenolysis ring-coupling reactions producing hydrocarbons, some with enhanced molecular weight.

Short communication: Dairy bedding type affects survival of Prototheca in vitro.

PubMed

Adhikari, N; Bonaiuto, H E; Lichtenwalner, A B

2013-01-01

Protothecae are algal pathogens, capable of causing bovine mastitis, that are unresponsive to treatment; they are believed to have an environmental reservoir. The role of bedding management in control of protothecal mastitis has not been studied. The purpose of this study was to evaluate the growth of either environmental or mastitis-associated Prototheca genotypes in dairy bedding materials that are commonly used in Maine. Prototheca zopfii genotypes 1 and 2 (gt1 and gt2) were inoculated into sterile broth only (control ), kiln-dried spruce shavings, "green" hemlock sawdust, sand, or processed manure-pack beddings with broth, and incubated for 2 d. Fifty microliters of each isolate was then cultured onto plates and the resulting colonies counted at 24 and 48 h postinoculation. Shavings were associated with significantly less total Prototheca growth than other bedding types. Growth of P. zopfii gt1 was significantly higher than that of gt2 in the manure-pack bedding material. Spruce shavings, compared with manure, sand, or sawdust, may be a good bedding type to prevent growth of Prototheca. Based on these in vitro findings, bedding type may affect Prototheca infection of cattle in vivo. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Effects of alternative deep bedding options on dairy cow preference, lying behavior, cleanliness, and teat end contamination.

PubMed

Wolfe, T; Vasseur, E; DeVries, T J; Bergeron, R

2018-01-01

Cows spend more time lying down when stalls are soft and dry, and bedding plays a key role in the comfort of the lying surface. The first objective of this study (experiment 1) was to compare cow preference for 2 types of alternative deep-bedding materials, switchgrass and switchgrass-lime, using wheat straw on a rubber mat as a control. Nine Holstein lactating cows were submitted in trios to a 3-choice preference test over 14 d (2 d of adaptation, 3 d of restriction to each stall, and 3 d of free access to all 3 stalls). Cows were housed individually in pens containing 3 stalls with different lying surfaces: (1) rubber mat with chopped wheat straw (WS); (2) deep-bedded switchgrass (SG); and (3) deep-bedded switchgrass, water, and lime mixture (SGL). The second objective (experiment 2) was to test, in freestall housing, the effects of these 3 types of bedding on lying behavior, cow cleanliness, and teat end bacterial contamination. Bedding treatments were compared in a 3 × 3 Latin square design using 24 cows split into groups of 8, with bedding materials being switched every 4 wk. Lying behavior was measured with data loggers in both studies. During experiment 1, cows chose to spend more time lying and had more frequent lying bouts on SG (9.4 h/d; 8.2 bouts/d) than on SGL (1.0 h/d; 0.9 bouts/d). They also spent more time standing and stood more frequently in stalls with SG (2.0 h/d; 10.1 bouts/d) than in those with SGL (0.6 h/d; 2.6 bouts/d), and stood longer in stalls with SG than with WS (0.6 h/d). In experiment 2, the total lying time, frequency of lying bouts, and mean lying bout duration were, on average, 9.7 ± 1.03 h/d, 8.2 ± 0.93 bouts/d, and 1.2 ± 0.06 h/bout, respectively, and did not differ between treatments. No treatment effects were found for cow cleanliness scores. Bedding dry matter was highest for SG (74.1%), lowest for SGL (63.5%), and intermediate for WS (68.6%) [standard error of the mean (SEM) = 1.57%]. This may explain the higher teat end count of coliforms for cows on SGL (0.92 log 10 cfu/g) compared with WS (0.13 log 10 cfu/g) (SEM = 0.144 log 10 cfu/g). In conclusion, cows preferred the deep-bedded switchgrass surface over the other 2 surfaces, and deep-bedded switchgrass appears to be a suitable bedding alternative for dairy cows. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Removal of nutrients from combined sewer overflows and lake water in a vertical-flow constructed wetland system.

PubMed

Gervin, L; Brix, H

2001-01-01

Lake Utterslev is situated in a densely built-up area of Copenhagen, and is heavily eutrophicated from combined sewer overflows. At the same time the lake suffers from lack of water. Therefore, a 5,000 m2 vertical flow wetland system was constructed in 1998 to reduce the phosphorus discharge from combined sewer overflows without reducing the water supply to the lake. During dry periods the constructed wetland is used to remove phosphorus from the lake water. The system is designed as a 90 m diameter circular bed with a bed depth of c. 2 m. The system is isolated from the surroundings by a polyethylene membrane. The bed medium consists of a mixture of gravel and crushed marble, which has a high binding capacity for phosphorus. The bed is located within the natural littoral zone of the lake and is planted with common reed (Phragmites australis). The constructed wetland is intermittently loaded with combined sewer overflow water or lake water and, after percolation through the bed medium, the water is collected in a network of drainage pipes at the bottom of the bed and pumped to the lake. The fully automated loading cycle results in alternating wet and dry periods. During the initial two years of operation, the phosphorus removal for combined sewer overflows has been consistently high (94-99% of inflow concentrations). When loaded with lake water, the phosphorus removal has been high during summer (71-97%) and lower during winter (53-75%) partly because of lower inlet concentrations. Effluent phosphorus concentrations are consistently low (0.03-0.04 mg/L). Ammonium nitrogen is nitrified in the constructed wetland, and total suspended solids and COD are generally reduced to concentrations below 5 mg/L and 25 mg/L, respectively. The study documents that a subsurface flow constructed wetland system can be designed and operated to effectively remove phosphorus and other pollutants from combined sewer overflows and eutrophicated lake water.

Kinetics of thermophilic anaerobes in fixed-bed reactors.

PubMed

Perez, M; Romero, L I; Sales, D

2001-08-01

The main objective of this study is to estimate growth kinetic constants and the concentration of "active" attached biomass in two anaerobic thermophilic reactors which contain different initial sizes of immobilized anaerobic mixed cultures and decompose distillery wastewater. This paper studies the substrate decomposition in two lab-scale fixed-bed reactors operating at batch conditions with corrugated tubes as support media. It can be demonstrated that high micro-organisms-substrate ratios favor the degradation activity of the different anaerobic cultures, allowing the stable operation without lag-phases and giving better quality in effluent. The kinetic parameters obtained--maximum specific growth rates (mu(max)), non-biodegradable substrate (S(NB)) and "active or viable biomass" concentrations (X(V0))--were obtained by applying the Romero kinetic model [L.I. Romero, 1991. Desarrollo de un modelo matemático general para los procesos fermentativos, Cinética de la degradación anaerobia, Ph.D. Thesis, University of Cádiz (Spain), Serv. Pub. Univ. Cádiz], with COD as substrate and methane (CH4) as the main product of the anaerobic process. This method is suitable to calculate and to differentiate the main kinetic parameters of both the total anaerobic mixed culture and the methanogenic population. Comparison of experimental measured concentration of volatile attached solids (VS(att)) in both reactors with the estimated "active" biomass concentrations obtained by applying Romero kinetic model [L.I. Romero, 1991. Desarrollo de un modelo matemático general para los procesos fermentativos, Cinética de la degradación anaerobia, Ph.D. Thesis, University of Cádiz (Spain), Serv. Pub. Univ. Cádiz] shows that a large amount of inert matter is present in the fixed-bed reactor.

A critical review on the spray drying of fruit extract: effect of additives on physicochemical properties.

PubMed

Krishnaiah, Duduku; Nithyanandam, Rajesh; Sarbatly, Rosalam

2014-01-01

Spray drying accomplishes drying while particles are suspended in the air and is one method in the family of suspended particle processing systems, along with fluid-bed drying, flash drying, spray granulation, spray agglomeration, spray reaction, spray cooling, and spray absorption. This drying process is unique because it involves both particle formation and drying. The present paper reviews spray drying of fruit extracts, such as acai, acerola pomace, gac, mango, orange, cactus pear, opuntia stricta fruit, watermelon, and durian, and the effects of additives on physicochemical properties such as antioxidant activity, total carotenoid content, lycopene and β-carotene content, hygroscopy, moisture content, volatile retention, stickiness, color, solubility, glass transition temperature, bulk density, rehydration, caking, appearance under electron microscopy, and X-ray powder diffraction. The literature clearly demonstrates that the effect of additives and encapsulation play a vital role in determining the physicochemical properties of fruit extract powder. The technical difficulties in spray drying of fruit extracts can be overcome by modifying the spray dryer design. It also reveals that spray drying is a novel technology for converting fruit extract into powder form.

Citric Acid Production from Orange Peel Wastes by Solid-State Fermentation

PubMed Central

Torrado, Ana María; Cortés, Sandra; Manuel Salgado, José; Max, Belén; Rodríguez, Noelia; Bibbins, Belinda P.; Converti, Attilio; Manuel Domínguez, José

2011-01-01

Valencia orange (Citrus sinensis) peel was employed in this work as raw material for the production of citric acid (CA) by solid-state fermentation (SSF) of Aspergillus niger CECT-2090 (ATCC 9142, NRRL 599) in Erlenmeyer flasks. To investigate the effects of the main operating variables, the inoculum concentration was varied in the range 0.5·103 to 0.7·108 spores/g dry orange peel, the bed loading from 1.0 to 4.8 g of dry orange peel (corresponding to 35-80 % of the total volume), and the moisture content between 50 and 100 % of the maximum water retention capacity (MWRC) of the material. Moreover, additional experiments were done adding methanol or water in different proportions and ways. The optimal conditions for CA production revealed to be an inoculum of 0.5·106 spores/g dry orange peel, a bed loading of 1.0 g of dry orange peel, and a humidification pattern of 70 % MWRC at the beginning of the incubation with posterior addition of 0.12 mL H2O/g dry orange peel (corresponding to 3.3 % of the MWRC) every 12 h starting from 62 h. The addition of methanol was detrimental for the CA production. Under these conditions, the SSF ensured an effective specific production of CA (193 mg CA/g dry orange peel), corresponding to yields of product on total initial and consumed sugars (glucose, fructose and sucrose) of 376 and 383 mg CA/g, respectively. These results, which demonstrate the viability of the CA production by SSF from orange peel without addition of other nutrients, could be of interest to possible, future industrial applications. PMID:24031646

Geology and mineral resources of the Mud Springs Ranch Quadrangle, Sweetwater County, Wyoming

USGS Publications Warehouse

Roehler, Henry W.

1979-01-01

The Mud Springs Ranch quadrangle occupies an area of 56 mF (square miles) on the southeast flank of the Rock Springs uplift in southwestern Wyoming. The climate is arid and windy. The landscape is mostly poorly vegetated and consists of north-trending ridges and valleys that are dissected by dry drainages. Sedimentary rocks exposed in the quadrangle are 5,400 ft (feet) thick and are mostly gray sandstone, siltstone, and shale, gray and brown carbonaceous shale, and thin beds of coal. They compose the Blair, Rock Springs, Ericson, Almond, and Lewis Formations of Cretaceous age and the Fort Union Formation of Paleocene age. The structure is mostly homoclinal, having southeast dips of 5?-12? in the northern part of the quadrangle, but minor plunging folds and one small fault are present in the southern part of the quadrangle. Three coal beds in the Fort Union Formation and 15 coal beds in the Almond Formation exceed 2.5 ft in thickness, are under less than 3,000 ft of overburden, and are potentially minable. Geographic stratigraphic, and resource data are present for each bed of minable coal. The total minable coal resources are estimated to be about 283 million short tons. Nine coal and rock samples from outcrops were analyzed to determine their quality and chemical composition. Four dry oil and gas test wells have been drilled within the quadrangle area, but structurally controlled stratigraphic-trap prospects remain untested.

The hydrological behaviour of extensive and intensive green roofs in a dry climate.

PubMed

Razzaghmanesh, M; Beecham, S

2014-11-15

This paper presents the results of a hydrological investigation of four medium scale green roofs that were set up at the University of South Australia. In this study, the potential of green roofs as a source control device was investigated over a 2 year period using four medium size green roof beds comprised of two growth media types and two media depths. During the term of this study, 226 rainfall events were recorded and these were representative of the Adelaide climate. In general, there were no statistically significant differences between the rainfall and runoff parameters for the intensive and extensive beds except for peak attenuation and peak runoff delay, for which higher values were recorded in the intensive beds. Longer dry periods generally resulted in higher retention coefficients and higher retention was also recorded in warmer seasons. The average retention coefficient for intensive systems (89%) was higher than for extensive systems (74%). It was shown that rainfall depth, intensity, duration and also average dry weather period between events can change the retention performance and runoff volume of the green roofs. Comparison of green and simulated conventional roofs indicated that the former were able to mitigate the peak of runoff and could delay the start of runoff. These characteristics are important for most source control measures. The recorded rainfall and runoff data displayed a non-linear relationship. Also, the results indicated that continuous time series modelling would be a more appropriate technique than using peak rainfall intensity methods for green roof design and simulation. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluation of ADCP apparent bed load velocity in a large sand-bed river: Moving versus stationary boat conditions

USGS Publications Warehouse

Jamieson, E.C.; Rennie, C.D.; Jacobson, R.B.; Townsend, R.D.

2011-01-01

Detailed mapping of bathymetry and apparent bed load velocity using a boat-mounted acoustic Doppler current profiler (ADCP) was carried out along a 388-m section of the lower Missouri River near Columbia, Missouri. Sampling transects (moving boat) were completed at 5- and 20-m spacing along the study section. Stationary (fixed-boat) measurements were made by maintaining constant boat position over a target point where the position of the boat did not deviate more than 3 m in any direction. For each transect and stationary measurement, apparent bed load velocity (vb) was estimated using ADCP bottom tracking data and high precision real-time kinematic (RTK) global positioning system (GPS). The principal objectives of this research are to (1) determine whether boat motion introduces a bias in apparent bed load velocity measurements; and (2) evaluate the reliability of ADCP bed velocity measurements for a range of sediment transport environments. Results indicate that both high transport (vb>0.6 m/s) and moving-boat conditions (for both high and low transport environments) increase the relative variability in estimates of mean bed velocity. Despite this, the spatially dense single-transect measurements were capable of producing detailed bed velocity maps that correspond closely with the expected pattern of sediment transport over large dunes. ?? 2011 American Society of Civil Engineers.

Field application of a planted fixed bed reactor (PFR) for support media and rhizosphere investigation using undisturbed samples from full-scale constructed wetlands.

PubMed

Barreto, A B; Vasconcellos, G R; von Sperling, M; Kuschk, P; Kappelmeyer, U; Vasel, J L

2015-01-01

This study presents a novel method for investigations on undisturbed samples from full-scale horizontal subsurface-flow constructed wetlands (HSSFCW). The planted fixed bed reactor (PFR), developed at the Helmholtz Center for Environmental Research (UFZ), is a universal test unit for planted soil filters that reproduces the operational conditions of a constructed wetland (CW) system in laboratory scale. The present research proposes modifications on the PFR original configuration in order to allow its operation in field conditions. A mobile device to obtain undisturbed samples from real-scale HSSFCW was also developed. The experimental setting is presented with two possible operational configurations. The first allows the removal and replacement of undisturbed samples in the CW bed for laboratory investigations, guaranteeing sample integrity with a mobile device. The second allows the continuous operation of the PFR and undisturbed samples as a fraction of the support media, reproducing the same environmental conditions outside the real-scale system. Investigations on the hydrodynamics of the adapted PFR were carried out with saline tracer tests, validating the proposed adaptation. Six adapted PFR units were installed next to full-scale HSSFCW beds and fed with interstitial liquid pumped from two regions of planted and unplanted support media. Fourteen points were monitored along the system, covering carbon fractions, nitrogen and sulfate. The results indicate the method as a promising tool for investigations on CW support media, rhizosphere and open space for studies on CW modeling, respirometry, kinetic parameters, microbial communities, redox potential and plant influence on HSSFCW.

Modified dry limestone process for control of sulfur dioxide emissions

DOEpatents

Shale, Correll C.; Cross, William G.

1976-08-24

A method and apparatus for removing sulfur oxides from flue gas comprise cooling and conditioning the hot flue gas to increase the degree of water vapor saturation prior to passage through a bed of substantially dry carbonate chips or lumps, e.g., crushed limestone. The reaction products form as a thick layer of sulfites and sulfates on the surface of the chips which is easily removed by agitation to restore the reactive surface of the chips.

Novel dry-desulfurization process using Ca(OH)2/fly ash sorbent in a circulating fluidized bed.

PubMed

Matsushima, Norihiko; Li, Yan; Nishioka, Masateru; Sadakata, Masayoshi; Qi, Haiying; Xu, Xuchang

2004-12-15

A dry-desulfurization process using Ca(OH)2/fly ash sorbent and a circulating fluidized bed (CFB) was developed. Its aim was to achieve high SO2 removal efficiency without humidification and production of CaSO4 as the main byproduct. The CaSO4 produced could be used to treat alkalized soil. An 83% SO2 removal rate was demonstrated, and a byproduct with a high CaSO4 content was produced through baghouse ash. These results indicated that this process could remove SO2 in flue gas with a high efficiency under dry conditions and simultaneously produce soil amendment. It was shown that NO and NO2 enhanced the SO2 removal rate markedly and that NO2 increased the amount of CaSO4 in the final product more than NO. These results confirmed that the significant effects of NO and NO2 on the SO2 removal rate were due to chain reactions that occurred under favorable conditions. The amount of baghouse ash produced increased as the reaction progressed, indicating that discharge of unreacted Ca(OH)2 from the reactor was suppressed. Hence, unreacted Ca(OH)2 had a long residence time in the CFB, resulting in a high SO2 removal rate. It was also found that 350 degrees C is the optimum reaction temperature for dry desulfurization in the range tested (320-380 degrees C).

40 CFR 761.62 - Disposal of PCB bulk product waste.

Code of Federal Regulations, 2012 CFR

2012-07-01

... molded rubber parts and components; applied dried paints, varnishes, waxes or other similar coatings or... released or dispersed by wind or other action; or (2) Under asphalt as part of a road bed. [63 FR 35451...

40 CFR 761.62 - Disposal of PCB bulk product waste.

Code of Federal Regulations, 2014 CFR

2014-07-01

... molded rubber parts and components; applied dried paints, varnishes, waxes or other similar coatings or... released or dispersed by wind or other action; or (2) Under asphalt as part of a road bed. [63 FR 35451...

40 CFR 761.62 - Disposal of PCB bulk product waste.

Code of Federal Regulations, 2013 CFR

2013-07-01

... molded rubber parts and components; applied dried paints, varnishes, waxes or other similar coatings or... released or dispersed by wind or other action; or (2) Under asphalt as part of a road bed. [63 FR 35451...

40 CFR 761.62 - Disposal of PCB bulk product waste.

Code of Federal Regulations, 2011 CFR

2011-07-01

... molded rubber parts and components; applied dried paints, varnishes, waxes or other similar coatings or... released or dispersed by wind or other action; or (2) Under asphalt as part of a road bed. [63 FR 35451...

Food-processes wastewaters treatment using food solid-waste materials as adsorbents or absorbents

NASA Astrophysics Data System (ADS)

Rapti, Ilaira; Georgopoulos, Stavros; Antonopoulou, Maria; Konstantinou, Ioannis; Papadaki, Maria

2016-04-01

The wastewaters generated by olive-mills during the production of olive oil, wastewaters from a dairy and a cow-farm unit and wastewaters from a small food factory have been treated by means of selected materials, either by-products of the same units, or other solid waste, as absorbents or adsorbents in order to identify the capacity of those materials to remove organic load and toxicity from the aforementioned wastewaters. The potential of both the materials used as absorbents as well as the treated wastewaters to be further used either as fertilizers or for agricultural irrigation purposes are examined. Dry olive leaves, sheep wool, rice husks, etc. were used either in a fixed-bed or in a stirred batch arrangemen,t employing different initial concentrations of the aforementioned wastewaters. The efficiency of removal was assessed using scpectrophotometric methods and allium test phytotoxicity measurements. In this presentation the response of each material employed is shown as a function of absorbent/adsorbent quantity and kind, treatment time and wastewater kind and initial organic load. Preliminary results on the potential uses of the adsorbents/absorbents and the treated wastewaters are also shown. Keywords: Olive-mill wastewaters, dairy farm wastewaters, olive leaves, zeolite, sheep wool

Multifaceted effects of HZSM-5 (Proton-exchanged Zeolite Socony Mobil-5) on catalytic cracking of pinewood pyrolysis vapor in a two-stage fixed bed reactor.

PubMed

Wang, Yimeng; Wang, Jie

2016-08-01

The pinewood was pyrolyzed in the first reactor at a heating rate of 10°Cmin(-1) from room temperature to 700°C, and the vapor was allowed to be cracked through the second reactor in a temperature range of 450-750°C without and with HZSM-5. Attempts were made to determine a wide spectrum of gaseous and liquid products, as well as the mass and element partitions to gas, water, bio-oil, coke and char. HZSM-5 showed a preferential deoxygenation effect via the facilitated decarbonylation and decarboxylation with the inhibited dehydration at 550-600°C. This catalyst also displayed a high selectivity for the formations of aromatic hydrocarbons and olefins by the promoted hydrogen transfer to these products at 550-600°C. The bio-oil produced with HZSM-5 at 500-600°C had the yields of 14.5-16.8%, the high heat values of 39.1-42.4MJkg(-1), and the energy recoveries of 33-35% (all dry biomass basis). Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of attrition test methods: ASTM standard fluidized bed vs jet cup

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhao, R.; Goodwin, J.G. Jr.; Jothimurugesan, K.

2000-05-01

Attrition resistance is one of the key design parameters for catalysts used in fluidized-bed and slurry phase types of reactors. The ASTM fluidized-bed test has been one of the most commonly used attrition resistance evaluation methods; however, it requires the use of 50 g samples--a large amount for catalyst development studies. Recently a test using the jet cup requiring only 5 g samples has been proposed. In the present study, two series of spray-dried iron catalysts were evaluated using both the ASTM fluidized-bed test and a test based on the jet cup to determine this comparability. It is shown thatmore » the two tests give comparable results. This paper, by reporting a comparison of the jet-cup test with the ASTM standard, provides a basis for utilizing the more efficient jet cup with confidence in catalyst attrition studies.« less

Waves plus currents at a right angle: The rippled bed case

NASA Astrophysics Data System (ADS)

Faraci, C.; Foti, E.; Musumeci, R. E.

2008-07-01

The present paper deals with wave plus current flow over a fixed rippled bed. More precisely, modifications of the current profiles due to the superimposition of orthogonal cylindrical waves have been investigated experimentally. Since the experimental setup permitted only the wave dominated regime to be investigated (i.e., the regime where orbital velocity is larger than current velocity), also a numerical k-ɛ turbulence closure model has been developed in order to study a wider range of parameters, thus including the current dominated regime (i.e., where current velocity is larger than wave orbital one). In both cases a different response with respect to the flat bed case has been found. Indeed, in the flat bed case laminar wave boundary layers in a wave dominated regime induce a decrease in bottom shear stresses, while the presence of a rippled bed behaves as a macroroughness, which causes the wave boundary layer to become turbulent and therefore the current velocity near the bottom to be smaller than the one in the case of current only, with a consequent increase in the current bottom roughness.

Stream bed temperature profiles as indicators of percolation characteristics beneath arroyos in the middle Rio Grande Basin, USA

USGS Publications Warehouse

Constantz, J.; Thomas, C.L.

1997-01-01

Stream bed temperature profiles were monitored continuously during water year 1990 and 1991 (WY90 and 91) in two New Mexico arroyos, similar in their meteorological features and dissimilar in their hydrological features. Stream bed temperature profiles between depths of 30 and 300 cm were examined to determine whether temporal changes in temperature profiles represent accurate indicators of the timing, depth and duration of percolation in each stream bed. These results were compared with stream flow, air temperature, and precipitation records for WY90 and 91, to evaluate the effect of changing surface conditions on temperature profiles. Temperature profiles indicate a persistently high thermal gradient with depth beneath Grantline Arroyo, except during a semi-annual thermal reversal in spring and autumn. This typifies the thermal response of dry sediments with low thermal conductivities. High thermal gradients were disrupted only during infrequent stream flows, followed by rapid re-establishment of high gradients. The stream bed temperature at 300 cm was unresponsive to individual precipitation or stream flow during WY90 and 91. This thermal pattern provides strong evidence that most seepage into Grantline Arroyo failed to percolate at a sufficient rate to reach 300 cm before being returned to the atmosphere. A distinctly different thermal pattern was recorded beneath Tijeras Arroyo. Low thermal gradients between 30 and 300 cm and large diurnal variations in temperature, suggest that stream flow created continuous, advection-dominated heat transport for over 300 days, annually. Beneath Tijeras Arroyo, low thermal gradients were interrupted only briefly during periodic, dry summer conditions. Comparisons of stream flow records for WY90 and 91 with stream bed temperature profiles indicate that independent analysis of thermal patterns provides accurate estimates of the timing, depth and duration of percolation beneath both arroyos. Stream flow loss estimates indicate that seepage rates were 15 times greater for Tijeras Arroyo than for Grantline Arroyo, which supports qualitative conclusions derived from analysis of stream bed temperature responses to surface conditions. ?? 1997 John Wiley & Sons, Ltd.

REMOVING RADIUM FROM WATER BY PLAIN AND TREATED ACTIVATED ALUMINA

EPA Science Inventory

The research determined the feasibility of using BaSO4-impregnated activated alumina and plain activated alumina for radium removal from groundwater by fixed-bed adsorption. The major factors influencing radium adsorption onto the two types of alumina were identified. The radium ...

Metered oxygen supply aids treatment of domestic sewage

NASA Technical Reports Server (NTRS)

Weliky, N.; Hooper, T. J.; Silverman, H. P.

1972-01-01

Microbiological fixed-bed process was developed in which supplementary oxygen required by microbial species is supplied by electrochemical device. Rate of addition of oxygen to waste treatment process is controlled to maintain aerobic metabolism and prevent anaerobic metabolisms which produce odorous or toxic products.

A NOVEL SEPARATION TECHNOLOGY FOR REMOVAL RECOVERY OF METALS FROM AQUEOUS SOLUTIONS

EPA Science Inventory

Recovery/Recycling of metal ions from industrial process waste streams is a preferred alternative to disposal by conventional techniques. This paper presents methods for preparation of inorganic chemically active adsorbents to be used in fixed bed adsorbers. Methods for immobiliz...

Catalytic pyrolysis of Alcea pallida stems in a fixed-bed reactor for production of liquid bio-fuels.

PubMed

Aysu, Tevfik

2015-09-01

Pyrolysis of Alcea pallida stems was performed in a fixed-bed tubular reactor with and without catalyst at three different temperatures. The effects of pyrolysis parameters including temperature and catalyst on the product yields were investigated. It was found that higher temperature resulted in lower liquid (bio-oil) and solid (bio-char) yields and higher gas yields. Catalysts had different effects on product yields and composition of bio-oils. Liquid yields were increased in the presence of zinc chloride and alumina but decreased with calcium hydroxide, tincal and ulexite. The highest bio-oil yield (39.35%) by weight including aqueous phase was produced with alumina catalyst at 500 °C. The yields of bio-char, bio-oil and gas produced, as well as the compositions of the resulting bio-oils were determined by elemental analysis, TGA, FT-IR and GC-MS. 160 different compounds were identified by GC-MS in the bio-oils obtained at 500 °C. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of bacterial lipase on anaerobic co-digestion of slaughterhouse wastewater and grease in batch condition and continuous fixed-bed reactor.

PubMed

Affes, Maha; Aloui, Fathi; Hadrich, Fatma; Loukil, Slim; Sayadi, Sami

2017-10-10

This study aimed to investigate the effects of bacterial lipase on biogas production of anaerobic co-digestion of slaughterhouse wastewater (SHWW) and hydrolyzed grease (HG). A neutrophilic Staphylococcus xylosus strain exhibiting lipolytic activity was used to perform microbial hydrolysis pretreatment of poultry slaughterhouse lipid rich waste. Optimum proportion of hydrolyzed grease was evaluated by determining biochemical methane potential. A high biogas production was observed in batch containing a mixture of slaughterhouse composed of 75% SHWW and 25% hydrolyzed grease leading to a biogas yield of 0.6 L/g COD introduced. Fixed bed reactor (FBR) results confirmed that the proportion of 25% of hydrolyzed grease gives the optimum condition for the digester performance. Biogas production was significantly high until an organic loading rate (OLR) of 2 g COD/L. d. This study indicates that the use of biological pre-treatment and FBR for the co-digestion of SHWW and hydrolyzed grease is feasible and effective.

In-situ upgrading of biomass pyrolysis vapors: catalyst screening on a fixed bed reactor.

PubMed

Stefanidis, S D; Kalogiannis, K G; Iliopoulou, E F; Lappas, A A; Pilavachi, P A

2011-09-01

In-situ catalytic upgrading of biomass fast pyrolysis vapors was performed in a fixed bed bench-scale reactor at 500°C, for catalyst screening purposes. The catalytic materials tested include a commercial equilibrium FCC catalyst (E-cat), various commercial ZSM-5 formulations, magnesium oxide and alumina materials with varying specific surface areas, nickel monoxide, zirconia/titania, tetragonal zirconia, titania and silica alumina. The bio-oil was characterized measuring its water content, the carbon-hydrogen-oxygen (by difference) content and the chemical composition of its organic fraction. Each catalytic material displayed different catalytic effects. High surface area alumina catalysts displayed the highest selectivity towards hydrocarbons, yielding however low organic liquid products. Zirconia/titania exhibited good selectivity towards desired compounds, yielding higher organic liquid product than the alumina catalysts. The ZSM-5 formulation with the highest surface area displayed the most balanced performance having a moderate selectivity towards hydrocarbons, reducing undesirable compounds and producing organic liquid products at acceptable yields. Copyright © 2011 Elsevier Ltd. All rights reserved.

Effect of operating conditions on the removal of Pb2+ by microporous titanosilicate ETS-10 in a fixed-bed column.

PubMed

Lv, Lu; Wang, Kean; Zhao, X S

2007-01-15

The breakthrough behavior of Pb2+ in an ETS-10 fixed bed was experimentally examined at various operating conditions. Results showed that the adsorption amount of Pb2+ ions per unit mass of ETS-10 particles in a column is about 1.68 mmol/g under the experimental conditions. This amount was not markedly affected by the operating conditions because of the rapid adsorption rate of Pb2+ ions on ETS-10. In the presence of competitive metal ions, the amount of Pb2+ adsorbed on ETS-10 was slightly reduced. An overshoot of the effluent concentrations of competitive metal ions Cu2+ and Cd2+ was observed in the adsorption systems of binary and ternary solutions. This is ascribed to the replacement of pre-adsorbed Cu2+ and Cd2+ ions by Pb2+ ions. The ETS-10 column broken up by Pb2+ ions can be regenerated by using an EDTA-Na2 solution and the regenerated column can be reused.

Production of Recombinant Rabies Virus Glycoprotein by Insect Cells in a Single-Use Fixed-Bed Bioreactor.

PubMed

Ventini-Monteiro, Daniella C; Astray, Renato M; Pereira, Carlos A

2018-01-01

A single-use fixed-bed bioreactor (iCELLis nano) can be used for cultivating non adherent insect cells, which can be then recovered for scaling up or for harvesting a membrane-associated viral glycoprotein with high quality in terms of preserved protein structure and biological function. Here, we describe the procedures for establishing genetically modified Drosophila melanogaster Schneider 2 (S2) cell cultures in the iCELLis nano bioreactor and for quantifying by ELISA the recombinant rabies virus glycoprotein (rRVGP) synthesized. By using the described protocol of production, the following performance can be regularly achieved: 1.7 ± 0.6 × 1E10 total cells; 2.4 ± 0.8 × 1E7 cells/mL and 1.2 ± 0.9 μg of rRVGP/1E7 cells; 1.5 ± 0.8 mg of total rRVGP.

Pyrolysis of Date palm waste in a fixed-bed reactor: Characterization of pyrolytic products.

PubMed

Bensidhom, Gmar; Ben Hassen-Trabelsi, Aïda; Alper, Koray; Sghairoun, Maher; Zaafouri, Kaouther; Trabelsi, Ismail

2018-01-01

The pyrolysis of several Tunisian Date Palm Wastes (DPW): Date Palm Rachis (DPR), Date Palm Leaflets (DPL), Empty Fruit Bunches (EFB) and Date Palm Glaich (DPG) was run using a fixed-bed reactor, from room temperature to 500°C, with 15°C/min as heating rate and -5°C as condensation temperature, in order to produce bio-oil, biochar and syngas. In these conditions, the bio-oil yield ranges from 17.03wt% for DPL to 25.99wt% for EFB. For the biochar, the highest yield (36.66wt%) was obtained for DPL and the lowest one (31.66wt%) was obtained from DPG while the syngas production varies from 39.10wt% for DPR to 46.31wt% DPL. The raw material and pyrolysis products have been characterized using elemental analysis thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM). The syngas composition has been characterized using gas analyzer. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of an energy-saving anaerobic hybrid membrane bioreactors for 2-chlorophenol-contained wastewater treatment.

PubMed

Wang, Yun-Kun; Pan, Xin-Rong; Sheng, Guo-Ping; Li, Wen-Wei; Shi, Bing-Jing; Yu, Han-Qing

2015-12-01

A novel energy-saving anaerobic hybrid membrane bioreactor (AnHMBR) with mesh filter, which takes advantage of anaerobic membrane bioreactor and fixed-bed biofilm reactor, is developed for low-strength 2-chlorophenol (2-CP)-contained wastewater treatment. In this system, the anaerobic membrane bioreactor is stuffed with granular activated carbon to construct an anaerobic hybrid fixed-bed biofilm membrane bioreactor. The effluent turbidity from the AnHMBR system was low during most of the operation period, and the chemical oxygen demand and 2-CP removal efficiencies averaged 82.3% and 92.6%, respectively. Furthermore, a low membrane fouling rate was achieved during the operation. During the AnHMBR operation, the only energy consumption was for feed pump. And a low energy demand of 0.0045-0.0063kWhm(-3) was estimated under the current operation conditions. All these results demonstrated that this novel AnHMBR is a sustainable technology for treating 2-CP-contained wastewater. Copyright © 2014 Elsevier Ltd. All rights reserved.

Study on co-pyrolysis characteristics of rice straw and Shenfu bituminous coal blends in a fixed bed reactor.

PubMed

Li, Shuaidan; Chen, Xueli; Liu, Aibin; Wang, Li; Yu, Guangsuo

2014-03-01

Co-pyrolysis behaviors of rice straw and Shenfu bituminous coal were studied in a fixed bed reactor under nitrogen atmosphere. The pyrolysis temperatures were 700°C, 800°C and 900°C, respectively. Six different biomass ratios were used. Gas, tar components were analyzed by a gas chromatograph and a gas chromatography-mass spectrometry respectively. Under co-pyrolysis conditions, the gas volume yields are higher than the calculated values. Co-pyrolysis tar contains more phenolics, less oxygenate compounds than calculated values. The addition of biomass changes the atmosphere during the pyrolysis process and promotes tar decomposition. The SEM results show that the differences between the blended char and their parents char are not significant. The results of char yields and ultimate analysis also show that no significant interactions exist between the two kinds of particles. The changes of gas yield and components are caused by the secondary reactions and tar decomposition. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biosorption of metal ions from aqueous solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Jiaping; Yiacoumi, Sotira

1997-01-01

Copper biosorption from aqueous solutions by calcium alginate is reported in this paper. The experimental section includes potentiometric titrations of biosorbents, batch equilibrium and kinetic studies of copper biosorption, as well as fixed-bed biosorption experiments. The potentiometric titration results show that the surface charge increases with decreasing pH. The biosorption of copper strongly depends on solution pH; the metal ion binding increases from 0 to 90 percent in pH ranging from 1.5 to 5.0. In addition, a decrease in ionic strength results in an increase of copper ion removal. Kinetic studies indicate that mass transfer plays an important role inmore » the biosorption rate. Furthermore, a fixed-bed biosorption experiment shows that calcium alginate has a significant capacity for copper ion removal. The two-pK Basic Stem model successfully represents the surface charge and equilibrium biosorption experimental data. The calculation results demonstrate that the copper removal may result from the binding of free copper and its hydroxide with surface functional groups of the biosorbents.« less

Thermodynamic modeling of small scale biomass gasifiers: Development and assessment of the ''Multi-Box'' approach.

PubMed

Vakalis, Stergios; Patuzzi, Francesco; Baratieri, Marco

2016-04-01

Modeling can be a powerful tool for designing and optimizing gasification systems. Modeling applications for small scale/fixed bed biomass gasifiers have been interesting due to their increased commercial practices. Fixed bed gasifiers are characterized by a wide range of operational conditions and are multi-zoned processes. The reactants are distributed in different phases and the products from each zone influence the following process steps and thus the composition of the final products. The present study aims to improve the conventional 'Black-Box' thermodynamic modeling by means of developing multiple intermediate 'boxes' that calculate two phase (solid-vapor) equilibriums in small scale gasifiers. Therefore the model is named ''Multi-Box''. Experimental data from a small scale gasifier have been used for the validation of the model. The returned results are significantly closer with the actual case study measurements in comparison to single-stage thermodynamic modeling. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of distributor on performance of a continuous fluidized bed dryer

NASA Astrophysics Data System (ADS)

Yogendrasasidhar, D.; Srinivas, G.; Pydi Setty, Y.

2018-03-01

Proper gas distribution is very important in fluidized bed drying in industrial practice. Improper distribution of gas may lead to non-idealities like channeling, short circuiting and accumulation which gives rise to non-uniform quality of dried product. Gas distribution depends on the distributor plate used. Gas distribution mainly depends on orifice diameter, number of orifices and opening area of the distributor plate. Small orifice diameter leads to clogging, and a large orifice diameter gives uneven distribution of gas. The present work involves experimental studies using different distributor plates and simulation studies using ASPEN PLUS steady state simulator. The effect of various parameters such as orifice diameter, number of orifices and the opening area of the distributor plate on the performance of fluidized bed dryer have been studied through simulation and experimentation. Simulations were carried out (i) with increasing air inlet temperature to study the characteristics of solid temperature and moisture in outlet (ii) with increasing orifice diameter and (iii) with increase in number orifices to study the solid outlet temperature profiles. It can be observed from the simulation that, an increase in orifice diameter and number orifices increases solid outlet temperature upto certain condition and then after there is no effect with further increase. Experiments were carried out with increasing opening area (3.4 to 42%) in the form of increasing orifice diameter keeping the number of orifices constant and increasing number of orifices of the distributor plate keeping the orifice diameter constant. It can be seen that the drying rate and solid outlet temperature increase upto certain condition and then after with further increase in the orifice diameter and number of orifices, the change in the drying rate and solid outlet temperature observed is little. The optimum values of orifice diameter and number of orifices from experimentation are found to be 5 mm and 60 (22% opening area).

Characterization and evaluation in vivo of baicalin-nanocrystals prepared by an ultrasonic-homogenization-fluid bed drying method.

PubMed

Shi-Ying, Jin; Jin, Han; Shi-Xiao, Jin; Qing-Yuan, Lv; Jin-Xia, Bai; Chen, Hong-Ge; Rui-Sheng, Li; Wei, Wu; Hai-Long, Yuan

2014-01-01

To improve the absorption and bioavailability of baicalin using a nanocrystal (or nanosuspension) drug delivery system. A tandem, ultrasonic-homogenization-fluid bed drying technology was applied to prepare baicalin-nanocrystal dried powders, and the physicochemical properties of baicalin-nanocrystals were characterized by scanning electron microscopy, photon correlation spectroscopy, powder X-ray diffraction, physical stability, and solubility experiments. Furthermore, in situ intestine single-pass perfusion experiments and pharmacokinetics in rats were performed to make a comparison between the microcrystals of baicalin and pure baicalin in their absorption properties and bioavailability in vivo. The mean particle size of baicalin-nanocrystals was 236 nm, with a polydispersity index of 0.173, and a zeta potential value of -34.8 mV, which provided a guarantee for the stability of the reconstituted nanosuspension. X-Ray diffraction results indicated that the crystallinity of baicalin was decreased through the ultrasonic-homogenization process. Physical stability experiments showed that the prepared baicalin-nanocrystals were sufficiently stable. It was shown that the solubility of baicalin in the form of nanocrystals, at 495 μg·mL(-1), was much higher than the baicalin-microcrystals and the physical mixture (135 and 86.4 μg·mL(-1), respectively). In situ intestine perfusion experiments demonstrated a clear advantage in the dissolution and absorption characteristics for baicalin-nanocrystals compared to the other formulations. In addition, after oral administration to rats, the particle size decrease from the micron to nanometer range exhibited much higher in vivo bioavailability (with the AUC(0-t) value of 206.96 ± 21.23 and 127.95 ± 14.41 mg·L(-1)·h(-1), respectively). The nanocrystal drug delivery system using an ultrasonic-homogenization-fluid bed drying process is able to improve the absorption and in vivo bioavailability of baicalin, compared with pure baicalin coarse powder and micronized baicalin. Copyright © 2014 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Facies architecture and stratigraphic evolution of aeolian dune and interdune deposits, Permian Caldeirão Member (Santa Brígida Formation), Brazil

NASA Astrophysics Data System (ADS)

Jones, Fábio Herbert; Scherer, Claiton Marlon dos Santos; Kuchle, Juliano

2016-05-01

The Permian Caldeirão Member (Santa Brígida Formation), located in the Tucano Central Basin, northeast region of Brazil, is characterized by a sandstone succession of aeolian origin that comprises the preserved deposits of dunes and interdunes. Grainflow and translatent wind-ripple strata, and frequent presence of reactivation surface, compose the cross-bedding of crescent aeolian dune deposits. The aeolian cross-strata show a mean dip toward the ENE. In places, interlayered with dune cross-beds, occur interdune units composed of facies indicative of dry, damp and wet condition of the substrate, suggesting spatial and/or temporal variations in the moisture content of the interdune accumulation surface. The presence of NNW current ripple cross-lamination in wet interdune areas indicates streamflows confined to interdune corridors and oriented perpendicular to aeolian transport direction. Lenses of damp and wet interdune strata exhibit mainly interdigitated and transitional relationships with the toe-sets of overlying aeolian dune units in sections parallel to aeolian transport, indicating that dune migration was contemporaneous with accumulation in adjacent interdunes. Lateral variations in the preserved thickness of the interdune units and the associated rare occurrence of abrupt and erosive contacts between interdune and overlying dune sets, suggest temporal variations in the angle of dune and interdune climb that may be related to high-frequency changes in water table position. Four stratigraphic intervals in the Caldeirão Member can be identified, two intervals showing cross-bedding of aeolian dunes without wet interdune areas and two intervals exhibiting aeolian dunes separated by wet interdune areas, marking the transition between dry aeolian systems (Intervals I and III) and wet aeolian systems (Intervals II and IV). The temporal alternations between dry and wet aeolian systems reflect changes in the availability of dry sand and/or the rate in the water table rise, possibly controlled by orbitally-driven climatic fluctuations.

Evaluation of soil manipulation to prepare engineered earthen waste covers for revegetation

DOE PAGES

Waugh, W. Joseph; Benson, Craig H.; Albright, William H.; ...

2015-10-21

Seven ripping treatments designed to improve soil physical conditions for revegetation were compared on a test pad simulating an earthen cover for a waste disposal cell. The field test was part of study of methods to convert compacted-soil waste covers into evapotranspiration covers. The test pad consisted of a compacted layer of fine-textured soil simulating a barrier protection layer overlain by a gravelly sand bedding layer and a cobble armor layer. Treatments included combinations of soil-ripping implements (conventional shank [CS], wing-tipped shank [WTS], and parabolic oscillating shank with wings [POS]), ripping depths, and number of passes. Dimensions, dry density, moisturemore » content, and particle size distribution of disturbance zones were determined in two trenches excavated across rip rows. The goal was to create a root-zone dry density between 1.2 and 1.6 Mg m-3 and a seedbed soil texture ranging from clay loam to sandy loam with low rock content. All treatments created V-shaped disturbance zones as measured on trench faces. Disturbance zone size was most influenced by ripping depth. Winged implements created larger disturbance zones. All treatments lifted fines into the bedding layer, moved gravel and cobble down into the fine-textured protection layer, and thereby disrupted the capillary barrier at the interface. Changes in dry density within disturbance zones were comparable for the CS and WTS treatments but were highly variable among POS treatments. Water content increased in the bedding layer and decreased in the protection layer after ripping. The POS at 1.2-m depth and two passes created the largest zone with a low dry density (1.24 Mg m-3) and the most favorable seedbed soil texture (gravely silt loam). Furthermore, ripping also created large soil aggregates and voids in the protection layer that may produce preferential flow paths and reduce water storage capacity.« less

Economical and ecological comparison of granular activated carbon (GAC) adsorber refill strategies.

PubMed

Bayer, Peter; Heuer, Edda; Karl, Ute; Finkel, Michael

2005-05-01

Technical constraints can leave a considerable freedom in the design of a technology, production or service strategy. Choosing between economical or ecological decision criteria then characteristically leads to controversial solutions of ideal systems. For the adaptation of granular-activated carbon (GAC) fixed beds, various technical factors determine the adsorber volume required to achieve a desired service life. In considering carbon replacement and recycling, a variety of refill strategies are available that differ in terms of refill interval, respective adsorber volume, and time-dependent use of virgin, as well as recycled GAC. Focusing on the treatment of contaminant groundwater, we compare cost-optimal reactor configurations and refill strategies to the ecologically best alternatives. Costs and consumption of GAC are quantified within a technical-economical framework. The emissions from GAC production out of hard coal, transport and recycling are equally derived through a life cycle impact assessment. It is shown how high discount rates lead to a preference of small fixed-bed volumes, and accordingly, a high number of refills. For fixed discount rates, the investigation reveals that both the economical as well as ecological assessment of refill strategies are especially sensitive to the relative valuation of virgin and recycled GAC. Since recycling results in economic and ecological benefits, optimized systems thus may differ only slightly.

Evaluation of the effectiveness factor along immobilized enzyme fixed-bed reactors: design of a reactor with naringinase covalently immobilized into glycophase-coated porous glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manjon, A.; Iborra, J.L.; Gomez, J.L.

A design equation is presented for packed-bed reactors containing immobilized enzymes in spherical porous particles with internal diffusion effects and obeying reversible one-intermediate Michaelis-Menten kinetics. The equation is also able to explain irreversible and competitive product inhibition kinetics. It allows the axial substrate profiles to be calculated and the dependence of the effectiveness factor along the reactor length to be continuously evaluated. The design equation was applied to explain the behavior of naringinase immobilized in Glycophase-coated porous glass operating in a packed-bed reactor and hydrolyzing both p-nitrophenyl-alpha-L-rhamnoside and naringin. The theoretically predicted results were found to fit well with experimentallymore » measured values. (Refs. 28).« less

Nitric Oxide Reduction over Sewage Sludge and Coal Chars at Conditions Relevant to Staged Fluidized Bed Combustion

NASA Astrophysics Data System (ADS)

Salatino, P.; Solimene, R.; Chirone, R.

The de-NOx potential of coal and of dried and pelletized sewage sludge, a waste-derived fuel candidate for cofiring with coal, is assessed. The experimental procedure is based on operation of a bench scale fluidized bed reactor where NO-doped nitrogen is contacted with batches of the fuel. A second type of experiment has been purposely designed to assess the loss of reactivity of chars toward gasification by NOx as char is heat-treated for pre-set times at temperatures typical of fluidized bed combustion. A simple phenomenological model is developed to shed light on the basic features of the interaction between heterogeneous char-NOx reaction and thermal annealing of the char.

CO-FIRING COAL: FEEDLOT AND LITTER BIOMASS (CFB AND CLB) FUELS IN PULVERIZED FUEL AND FIXED BED BURNERS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kalyan Annamalai; John Sweeten; Saqib Mukhtar

2003-08-28

Intensive animal feeding operations create large amounts of animal waste that must be safely disposed of in order to avoid environmental degradation. Cattle feedlots and chicken houses are two examples. In feedlots, cattle are confined to small pens and fed a high calorie grain-diet diet in preparation for slaughter. In chicken houses, thousands of chickens are kept in close proximity. In both of these operations, millions of tons of manure are produced every year. The manure could be used as a fuel by mixing it with coal in a 90:10 blend and firing it in an existing coal suspension firedmore » combustion systems. This technique is known as co-firing, and the high temperatures produced by the coal will allow the biomass to be completely combusted. Reburn is a process where a small percentage of fuel called reburn fuel is injected above the NO{sub x} producing, conventional coal fired burners in order to reduce NO{sub x}. The manure could also be used as reburn fuel for reducing NO{sub x} in coal fired plants. An alternate approach of using animal waste is to adopt the gasification process using a fixed bed gasifier and then use the gases for firing in gas turbine combustors. In this report, the cattle manure is referred to as feedlot biomass (FB) and chicken manure as litter biomass (LB). The report generates data on FB and LB fuel characteristics. Co-firing, reburn, and gasification tests of coal, FB, LB, coal: FB blends, and coal: LB blends and modeling on cofiring, reburn systems and economics of use of FB and LB have also been conducted. The biomass fuels are higher in ash, lower in heat content, higher in moisture, and higher in nitrogen and sulfur (which can cause air pollution) compared to coal. Small-scale cofiring experiments revealed that the biomass blends can be successfully fired, and NO{sub x} emissions will be similar to or lower than pollutant emissions when firing coal. Further experiments showed that biomass is twice or more effective than coal when used in a reburning process. Computer simulations for coal: LB blends were performed by modifying an existing computer code to include the drying and phosphorus (P) oxidation models. The gasification studies revealed that there is bed agglomeration in the case of chicken litter biomass due to its higher alkaline oxide content in the ash. Finally, the results of the economic analysis show that considerable fuel cost savings can be achieved with the use of biomass. In the case of higher ash and moisture biomass, the fuel cost savings is reduced.« less

Experimental Investigation and Aspen Plus Simulation of the MSW Pyrolysis Process

NASA Astrophysics Data System (ADS)

Ansah, Emmanuel

Municipal solid waste (MSW) is a potential feedstock for producing transportation fuels because it is readily available using an existing collection/transportation infrastructure and fees are provided by the suppliers or government agencies to treat MSW. North Carolina with a population of 9.4 millions generates 3.629 million metric tons of MSW each year, which contains about 113,396,356 TJs of energy. The average moisture content of MSW samples is 44.3% on a wet basis. About 77% of the dry MSW mass is combustible components including paper, organics, textile and plastics. The average heating values of MSW were 9.7, 17.5, and 22.7 MJ/kg on a wet basis, dry basis and dry combustible basis, respectively. The MSW generated in North Carolina can produce 7.619 million barrels of crude bio-oil or around 4% of total petroleum consumption in North Carolina. MSW can be thermally pyrolyzed into bio-oil in the absence of oxygen or air at a temperature of 500°C or above. As bio-oil can be easily stored and transported, compared to bulky MSW, landfill gas and electricity, pyrolysis offers significant logistical and economic advantages over landfilling and other thermal conversion processes such as combustion and gasification. Crude bio-oils produced from the pyrolysis of MSW can be further refined to transportation fuels in existing petroleum refinery facilities. The objective of this research is to analyze the technical and economic feasibility of pyrolyzing MSW into liquid transportation fuels. A combined thermogravimetric analyzer (TGA) and differential scanning calorimeter (DSC) instrument, which can serve as a micro-scale pyrolysis reactor, was used to simultaneously determine the degradation characteristics of MSW during pyrolysis. An ASPEN Plus-based mathematical model was further developed to analyze the technical and economic feasibility of pyrolysing of MSW into liquid transportation fuels in fixed bed reactors at varying operating conditions

40 CFR 60.41b - Definitions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... produces both electric (or mechanical) and useful thermal energy from the same primary energy source. Coke.... Conventional technology means wet flue gas desulfurization (FGD) technology, dry FGD technology, atmospheric fluidized bed combustion technology, and oil hydrodesulfurization technology. Distillate oil means fuel oils...

Growth of Azotobacter vinelandii in a solid-state fermentation of technical lignin.

PubMed

Zhang, Xiaoyong; Zhao, Hua; Zhang, Jianan; Li, Zuohu

2004-10-01

Azotobacter vinelandii was cultured on technical lignin, derived from Kraft pulping processes, for biofertilizer production in solid-state fermentation. The effects of the ratio of technical lignin to corn straw, initial water content, and material bed depth on the microorganisms were studied in detail. At 30 degrees C, technical lignin to corn straw at the ratio of 1:0.75, the bed depth of 5 cm, and 67% moisture content, A. vinelandii was grown and reached 4.2 x 10(10) cfu g(-1) dry rot after 36 h.

Fluidized bed and method and system for gas component capture

DOEpatents

Krutka, Holly; Wilson, Cody; Starns, Travis

2016-05-31

The present disclosure is directed to a process that allows dry sorbents to remove a target constituent, such as carbon dioxide (CO.sub.2), from a gas stream. A staged fluidized bed separator enables gas and sorbent to move in opposite directions. The sorbent is loaded with target constituent in the separator. It is then transferred to a regenerator where the target constituent is stripped. The temperature of the separator and regenerator are controlled. After it is removed from the regenerator, the sorbent is then transferred back to the separator.

Bedding material affects mechanical thresholds, heat thresholds and texture preference

PubMed Central

Moehring, Francie; O’Hara, Crystal L.; Stucky, Cheryl L.

2015-01-01

It has long been known that the bedding type animals are housed on can affect breeding behavior and cage environment. Yet little is known about its effects on evoked behavior responses or non-reflexive behaviors. C57BL/6 mice were housed for two weeks on one of five bedding types: Aspen Sani Chips® (standard bedding for our institute), ALPHA-Dri®, Cellu-Dri™, Pure-o’Cel™ or TEK-Fresh. Mice housed on Aspen exhibited the lowest (most sensitive) mechanical thresholds while those on TEK-Fresh exhibited 3-fold higher thresholds. While bedding type had no effect on responses to punctate or dynamic light touch stimuli, TEK-Fresh housed animals exhibited greater responsiveness in a noxious needle assay, than those housed on the other bedding types. Heat sensitivity was also affected by bedding as animals housed on Aspen exhibited the shortest (most sensitive) latencies to withdrawal whereas those housed on TEK-Fresh had the longest (least sensitive) latencies to response. Slight differences between bedding types were also seen in a moderate cold temperature preference assay. A modified tactile conditioned place preference chamber assay revealed that animals preferred TEK-Fresh to Aspen bedding. Bedding type had no effect in a non-reflexive wheel running assay. In both acute (two day) and chronic (5 week) inflammation induced by injection of Complete Freund’s Adjuvant in the hindpaw, mechanical thresholds were reduced in all groups regardless of bedding type, but TEK-Fresh and Pure-o’Cel™ groups exhibited a greater dynamic range between controls and inflamed cohorts than Aspen housed mice. PMID:26456764

First application of supported ionic liquid phase (SILP) catalysis for continuous methanol carbonylation.

PubMed

Riisager, Anders; Jørgensen, Betina; Wasserscheid, Peter; Fehrmann, Rasmus

2006-03-07

A solid, silica-supported ionic liquid phase (SILP) rhodium iodide Monsanto-type catalyst system, [BMIM][Rh(CO)2I2]-[BMIM]I-SiO2, exhibits excellent activity and selectivity towards acetyl products in fixed-bed, continuous gas-phase methanol carbonylation.

NOVEL OXIDANT FOR ELEMENTAL MERCURY CONTROL FROM FLUE GAS

EPA Science Inventory

A novel economical oxidant has been developed for elemental mercury (Hg(0)) removal from coal-fired boilers. The oxidant was rigorously tested in a lab-scale fixed-bed system with the Norit America's FGD activated carbon (DOE's benchmark sorbent) in a typical PRB subbituminous/l...

NOVEL OXIDANT FOR ELEMENTAL MERCURY CONTROL FROM FLUE GAS

EPA Science Inventory

The primary objective of this study is to develop and test advanced noncarbonaceous solid sorbent materials suitable for removing the elemental form of mercury from power plant emissions. An efficient and cost-effective novel Hg(0) oxidant was evaluated in a lab-scale fixed-bed ...

Cyclic process for producing methane from carbon monoxide with heat removal

DOEpatents

Frost, Albert C.; Yang, Chang-lee

1982-01-01

Carbon monoxide-containing gas streams are converted to methane by a cyclic, essentially two-step process in which said carbon monoxide is disproportionated to form carbon dioxide and active surface carbon deposited on the surface of a catalyst, and said carbon is reacted with steam to form product methane and by-product carbon dioxide. The exothermic heat of reaction generated in each step is effectively removed during each complete cycle so as to avoid a build up of heat from cycle-to-cycle, with particularly advantageous techniques being employed for fixed bed, tubular and fluidized bed reactor operations.

Cyclic process for producing methane in a tubular reactor with effective heat removal

DOEpatents

Frost, Albert C.; Yang, Chang-Lee

1986-01-01

Carbon monoxide-containing gas streams are converted to methane by a cyclic, essentially two-step process in which said carbon monoxide is disproportionated to form carbon dioxide and active surface carbon deposited on the surface of a catalyst, and said carbon is reacted with steam to form product methane and by-product carbon dioxide. The exothermic heat of reaction generated in each step is effectively removed during each complete cycle so as to avoid a build up of heat from cycle-to-cycle, with particularly advantageous techniques being employed for fixed bed, tubular and fluidized bed reactor operations.

Electrohydrodynamic (edh) drying of ginger slices (zingiber officinale)

NASA Astrophysics Data System (ADS)

Sumariyah; Khuriati, Ainie; Fachriyah, Enny

2018-05-01

Electrohydrodynamic (EHD) flow or ion wind of corona discharges has been generated utilizing pin-multi ring concentred electrodes. The pin was made of stainless steel with a tip diameter of 0.018 mm. The multi-ring constructed electrodes by a metal material connected to each other and each ring has a diameter of 24 mm, 16 mm and 8 mm in the same width and thickness is 4 mm and 1 mm. EHD was generated by using a DC high voltage of 5 kV. Pin as an active electrode of corona discharge and multi-ring concentric electrodes as a collector and passive electrodes. The ion wind or EHD flow is produced through changes in voltage and distance between electrodes. The ionic wind generated system outputs through multi-ring concentric electrodes which will further dry the sample. A circle ginger slices as a sample with a diameter of 26 mm with a thickness of 2 mm. The drying is done at the distance between the fixed electrodes of 4 mm and the varied voltages are 1.2 kV, 1.4 kV, and 1.6 kV. The sample drying time varied 30 minutes, 60 minutes, 90 minutes, 120 minutes and 150 minutes. The result of drying the sample at a fixed voltage is obtained moisture of ginger slices decreased with increased drying time.

Evaluation of a numerical model's ability to predict bed load transport observed in braided river experiments

NASA Astrophysics Data System (ADS)

Javernick, Luke; Redolfi, Marco; Bertoldi, Walter

2018-05-01

New data collection techniques offer numerical modelers the ability to gather and utilize high quality data sets with high spatial and temporal resolution. Such data sets are currently needed for calibration, verification, and to fuel future model development, particularly morphological simulations. This study explores the use of high quality spatial and temporal data sets of observed bed load transport in braided river flume experiments to evaluate the ability of a two-dimensional model, Delft3D, to predict bed load transport. This study uses a fixed bed model configuration and examines the model's shear stress calculations, which are the foundation to predict the sediment fluxes necessary for morphological simulations. The evaluation is conducted for three flow rates, and model setup used highly accurate Structure-from-Motion (SfM) topography and discharge boundary conditions. The model was hydraulically calibrated using bed roughness, and performance was evaluated based on depth and inundation agreement. Model bed load performance was evaluated in terms of critical shear stress exceedance area compared to maps of observed bed mobility in a flume. Following the standard hydraulic calibration, bed load performance was tested for sensitivity to horizontal eddy viscosity parameterization and bed morphology updating. Simulations produced depth errors equal to the SfM inherent errors, inundation agreement of 77-85%, and critical shear stress exceedance in agreement with 49-68% of the observed active area. This study provides insight into the ability of physically based, two-dimensional simulations to accurately predict bed load as well as the effects of horizontal eddy viscosity and bed updating. Further, this study highlights how using high spatial and temporal data to capture the physical processes at work during flume experiments can help to improve morphological modeling.

Fluidized bed combustion of high-volatile solid fuels: An assessment of char attrition and volatile matter segregation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chirone, R.; Marzocchella, A.; Salatino, P.

1999-07-01

A simple lumped-parameter model of a bubbling fluidized bed combustor fueled with high-volatile solid fuels is presented. The combustor is divided into three sections: the dense bed, the splashing region and the freeboard. Material balances on fixed carbon, volatile matter and oxygen are set up, taking into account fuel particle fragmentation and attrition, volatile matter segregation as well as postcombustion of both carbon fines and volatiles escaping the bed. A basic assumption of the model is that the combustion pathway that foes from the raw fuel to the combustion products proceeds via the formation of three phases: volatile matter, relativelymore » large non-elutriable char particles and fine char particles of elutriable size. The study is complemented by a simplified thermal balance on the splashing zone taking into account volatiles and elutriated fines postcombustion and radiative and convective heat fluxes to the bed and the freeboard. Results from calculations with either low- or high-volatile solid fuels indicate that low-volatile bituminous coal combustion takes place essentially in the bed mostly via coarse char particles combustion, while high-volatile biomass fuel combustion occurs to comparable extents both in the bed and in the splashing region of the combustor. Depending on the extent of volatile matter segregation with respect to the bed, a significant fraction of the heat is released into the splashing region of the combustor and this results into an increase of temperature in this region. Extensive bed solids recirculation associated to bubble bursting/solids ejection at the bed surface together with effective gas-solids heat transfer promotes thermal feedback from this region to the bed of as much as 90% of the heat release by volatile matter and elutriated fines afterburning.« less

(40)Ar/(39)Ar dating of Bed I, Olduvai Gorge, Tanzania, and the chronology of early Pleistocene climate change.

PubMed

Deino, Alan L

2012-08-01

(40)Ar/(39)Ar dating of tuffs and lavas of the late Pleistocene volcanic and sedimentary sequence of Olduvai Gorge, north-central Tanzania, provides the basis for a revision of Bed I chronostratigraphy. Bed I extends from immediately above the Naabi Ignimbrite at 2.038 ± 0.005 Ma to Tuff IF at 1.803 ± 0.002 Ma. Tuff IB, a prominent widespread marker tuff in the basin and a key to understanding hominin evolutionary chronologies and paleoclimate histories, has an age of 1.848 ± 0.003 Ma. The largest lake expansion event in the closed Olduvai lake basin during Bed I times encompassed the episode of eruption and emplacement of this tuff. This lake event is nearly coincident with the maximum precessional insolation peak of the entire Bed I/Lower Bed II interval, calculated from an astronomical model of the boreal summer orbital insolation time-series. The succeeding precessional peak also apparently coincides with the next youngest expansion of paleo-Lake Olduvai. The extreme wet/dry climate shifts seen in the upper part of Bed I occur during an Earth-orbital eccentricity maximum, similar to episodic lake expansions documented elsewhere in the East African Rift during the Neogene. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mechanical model testing of rebreathing potential in infant bedding materials

PubMed Central

Carleton, J.; Donoghue, A.; Porter, W.

1998-01-01

Rebreathing of expired air may be a lethal hazard for prone sleeping infants. This paper describes a mechanical model to simulate infant breathing, and examines the effects of bedding on exhaled air retention. Under simulated rebreathing conditions, the model allows the monitoring of raised carbon dioxide (CO2) inside an artificial lung-trachea system. Resulting levels of CO2 (although probably exaggerated in the mechanical model compared with an infant, due to the model's fixed breathing rate and volume) suggest that common bedding materials vary widely in inherent rebreathing potential. In face down tests, maximum airway CO2 ranged from less than 5% on sheets and waterproof mattresses to over 25% on sheepskins, bean bag cushions, and some pillows and comforters. Concentrations of CO2 decreased with increasing head angle of the doll, away from the face down position. Recreations of 29infant death scenes also showed large CO2 increases on some bedding materials, suggesting these infants could have died while rebreathing.

 PMID:9623394

Computing nonhydrostatic shallow-water flow over steep terrain

USGS Publications Warehouse

Denlinger, R.P.; O'Connell, D. R. H.

2008-01-01

Flood and dambreak hazards are not limited to moderate terrain, yet most shallow-water models assume that flow occurs over gentle slopes. Shallow-water flow over rugged or steep terrain often generates significant nonhydrostatic pressures, violating the assumption of hydrostatic pressure made in most shallow-water codes. In this paper, we adapt a previously published nonhydrostatic granular flow model to simulate shallow-water flow, and we solve conservation equations using a finite volume approach and an Harten, Lax, Van Leer, and Einfeldt approximate Riemann solver that is modified for a sloping bed and transient wetting and drying conditions. To simulate bed friction, we use the law of the wall. We test the model by comparison with an analytical solution and with results of experiments in flumes that have steep (31??) or shallow (0.3??) slopes. The law of the wall provides an accurate prediction of the effect of bed roughness on mean flow velocity over two orders of magnitude of bed roughness. Our nonhydrostatic, law-of-the-wall flow simulation accurately reproduces flume measurements of front propagation speed, flow depth, and bed-shear stress for conditions of large bed roughness. ?? 2008 ASCE.

Caribbean-Wide, Long-Term Study of Seagrass Beds Reveals Local Variations, Shifts in Community Structure and Occasional Collapse

PubMed Central

van Tussenbroek, Brigitta I.; Cortés, Jorge; Collin, Rachel; Fonseca, Ana C.; Gayle, Peter M. H.; Guzmán, Hector M.; Jácome, Gabriel E.; Juman, Rahanna; Koltes, Karen H.; Oxenford, Hazel A.; Rodríguez-Ramirez, Alberto; Samper-Villarreal, Jimena; Smith, Struan R.; Tschirky, John J.; Weil, Ernesto

2014-01-01

The CARICOMP monitoring network gathered standardized data from 52 seagrass sampling stations at 22 sites (mostly Thalassia testudinum-dominated beds in reef systems) across the Wider Caribbean twice a year over the period 1993 to 2007 (and in some cases up to 2012). Wide variations in community total biomass (285 to >2000 g dry m−2) and annual foliar productivity of the dominant seagrass T. testudinum (<200 and >2000 g dry m−2) were found among sites. Solar-cycle related intra-annual variations in T. testudinum leaf productivity were detected at latitudes > 16°N. Hurricanes had little to no long-term effects on these well-developed seagrass communities, except for 1 station, where the vegetation was lost by burial below ∼1 m sand. At two sites (5 stations), the seagrass beds collapsed due to excessive grazing by turtles or sea-urchins (the latter in combination with human impact and storms). The low-cost methods of this regional-scale monitoring program were sufficient to detect long-term shifts in the communities, and fifteen (43%) out of 35 long-term monitoring stations (at 17 sites) showed trends in seagrass communities consistent with expected changes under environmental deterioration. PMID:24594732

Effects of process parameters on solid self-microemulsifying particles in a laboratory scale fluid bed.

PubMed

Mukherjee, Tusharmouli; Plakogiannis, Fotios M

2012-01-01

The purpose of this study was to select the critical process parameters of the fluid bed processes impacting the quality attribute of a solid self-microemulsifying (SME) system of albendazole (ABZ). A fractional factorial design (2(4-1)) with four parameters (spray rate, inlet air temperature, inlet air flow, and atomization air pressure) was created by MINITAB software. Batches were manufactured in a laboratory top-spray fluid bed at 625-g scale. Loss on drying (LOD) samples were taken throughout each batch to build the entire moisture profiles. All dried granulation were sieved using mesh 20 and analyzed for particle size distribution (PSD), morphology, density, and flow. It was found that as spray rate increased, sauter-mean diameter (D(s)) also increased. The effect of inlet air temperature on the peak moisture which is directly related to the mean particle size was found to be significant. There were two-way interactions between studied process parameters. The main effects of inlet air flow rate and atomization air pressure could not be found as the data were inconclusive. The partial least square (PLS) regression model was found significant (P < 0.01) and predictive for optimization. This study established a design space for the parameters for solid SME manufacturing process.

Influence of in line monitored fluid bed granulation process parameters on the stability of Ethinylestradiol.

PubMed

Roßteuscher-Carl, Katrin; Fricke, Sabine; Hacker, Michael C; Schulz-Siegmund, Michaela

2015-12-30

Ethinylestradiol (EE) as a highly active and low dosed compound is prone to oxidative degradation. The stability of the drug substance is therefore a critical parameter that has to be considered during drug formulation. Beside the stability of the drug substance, granule particle size and moisture are critical quality attributes (CQA) of the fluid bed granulation process which influence the tableting ability of the resulting granules. Both CQA should therefore be monitored during the production process by process analytic technology (PAT) according to ICH Q8. This work focusses on the effects of drying conditions on the stability of EE in a fluid-bed granulation process. We quantified EE degradation products 6-alpha-hydroxy-EE, 6-beta-hydroxy-EE, 9(11)-dehydro-EE and 6-oxo-EE during long time storage and accelerated conditions. PAT-tools that monitor granule particle size (Spatial filtering technology) and granule moisture (Microwave resonance technology) were applied and compared with off-line methods. We found a relevant influence of residual granule moisture and thermic stress applied during granulation on the storage stability of EE, whereas no degradation was found immediately after processing. Hence we conclude that drying parameters have a relevant influence on long term EE stability. Copyright © 2015 Elsevier B.V. All rights reserved.

Stability of nonaqueous suspension formulations of plasma derived factor IX and recombinant human alpha interferon at elevated temperatures.

PubMed

Knepp, V M; Muchnik, A; Oldmark, S; Kalashnikova, L

1998-07-01

To identify a suitable nonaqueous, parenterally acceptable suspending vehicle whereby a therapeutic protein is delivered as a stable flowable powder, making it amenable to delivery from sustained delivery systems maintained at body temperature. Formulations of plasma derived Factor IX (pdFIX) and recombinant human alpha interferon (rhalpha-IFN) were formulated as dry powders, suspended in various vehicles (perfluorodecalin, perfluorotributylamine, methoxyflurane, polyethylene glycol 400, soybean oil, tetradecane or octanol) and stored at 37 degrees C. Stability was assessed by size exclusion chromatography, reverse phase chromatography, ion exchange chromatography, and bioassay, and was compared to the stability of dry powder formulations stored at 37 degrees C and -80 degrees C. PdFIX was stable when stored at 37 degrees C as a dry powder, or when the dry powder was suspended in the pharmaceutically acceptable vehicles perfluorodecalin or perfluorotributylamine. Suspensions of the powder in other pharmaceutically/parenterally acceptable vehicles such as soybean oil or PEG 400 resulted in aggregation and loss of bioactivity. A dry powder formulation of rhalpha-IFN suspended in perfluorodecalin was also stable at 37 degrees C. This study shows the potential utility of perfluorinated hydrocarbons as nonaqueous suspending vehicles for long term in-vivo delivery of therapeutic proteins.

The Relative Influence of Turbulence and Turbulent Mixing on the Adsorption of Mercury within a Gas-Sorbent Suspension

EPA Science Inventory

Our previous investigations demonstrated that entrained flow or in-flight adsorption can be a more effective and flexible approach to trace gas adsorption than fixed sorbent beds. The present investigation establishes the turbulent mixing that accompanies sorbent injection is an ...

Relationship Between Packing Structure and Porosity in Fixed Beds of Equilateral Cylindrical Particles

DTIC Science & Technology

2006-09-23

Roblee et al., 1958). Kubie (1988) derived a theoretical wall density function and compared it to experimental results. Reyes and Iglesia (1991) and...Engineering Chemistry Process Design and Development 7, 250-252. Kubie . J., 1988. Influence of containing walls on the distribution of voidage in

Responsive Copolymers for Enhanced Petroleum Recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCormick, Charles; Hester, Roger

The objectives of this work was to: (1) synthesize responsive, amphiphilic systems; (2) characterize molecular structure and solution behavior; (3) measure rheological properties of the aqueous fluids including behavior in fixed geometry flow profiles and beds; and (4) to tailor polymer compositions for in situ rheology control under simulated reservoir conditions.

Three-Point Gear/Lead Screw Positioning

NASA Technical Reports Server (NTRS)

Calco, Frank S.

1993-01-01

Triple-ganged-lead-screw positioning mechanism drives movable plate toward or away from fixed plate and keeps plates parallel to each other. Designed for use in tuning microwave resonant cavity. Other potential applications include adjustable bed plates and cantilever tail stocks in machine tools, adjustable platforms for optical equipment, and lifting platforms.

NOVEL ECONOMICAL HG(0) OXIDATION REAGENT FOR MERCURY EMISSIONS CONTROL FROM COAL-FIRED BOILERS

EPA Science Inventory

The authors have developed a novel economical additive for elemental mercury (Hg0) removal from coal-fired boilers. The oxidation reagent was rigorously tested in a lab-scale fixed-bed column with the Norit America's FGD activated carbon (DOE's benchmark sorbent) in a typical PRB...

BENCH-SCALE EVALUATION OF CALCIUM SORBENTS FOR ACID GAS EMISSION CONTROL

EPA Science Inventory

Calcium sorbents for acid gas emission control were evaluated for effectiveness in removing SO2/HCl and SO2/NO from simulated incinerator and boiler flue gases. All tests were conducted in a bench-scale reactor (fixed-bed) simulating fabric filter conditions in an acid gas remova...

THE EFFECT OF ACTIVATED CARBON SURFACE MOISTURE ON LOW TEMPERATURE MERCURY ADSORPTION

EPA Science Inventory

Experiments with elemental mercury (Hg0) adsorption by activated carbons were performed using a bench-scale fixed-bed reactor at room temperature (27 degrees C) to determine the role of surface moisture in capturing Hg0. A bituminous-coal-based activated carbon (BPL) and an activ...

Batch statistical process control of a fluid bed granulation process using in-line spatial filter velocimetry and product temperature measurements.

PubMed

Burggraeve, A; Van den Kerkhof, T; Hellings, M; Remon, J P; Vervaet, C; De Beer, T

2011-04-18

Fluid bed granulation is a batch process, which is characterized by the processing of raw materials for a predefined period of time, consisting of a fixed spraying phase and a subsequent drying period. The present study shows the multivariate statistical modeling and control of a fluid bed granulation process based on in-line particle size distribution (PSD) measurements (using spatial filter velocimetry) combined with continuous product temperature registration using a partial least squares (PLS) approach. Via the continuous in-line monitoring of the PSD and product temperature during granulation of various reference batches, a statistical batch model was developed allowing the real-time evaluation and acceptance or rejection of future batches. Continuously monitored PSD and product temperature process data of 10 reference batches (X-data) were used to develop a reference batch PLS model, regressing the X-data versus the batch process time (Y-data). Two PLS components captured 98.8% of the variation in the X-data block. Score control charts in which the average batch trajectory and upper and lower control limits are displayed were developed. Next, these control charts were used to monitor 4 new test batches in real-time and to immediately detect any deviations from the expected batch trajectory. By real-time evaluation of new batches using the developed control charts and by computation of contribution plots of deviating process behavior at a certain time point, batch losses or reprocessing can be prevented. Immediately after batch completion, all PSD and product temperature information (i.e., a batch progress fingerprint) was used to estimate some granule properties (density and flowability) at an early stage, which can improve batch release time. Individual PLS models relating the computed scores (X) of the reference PLS model (based on the 10 reference batches) and the density, respectively, flowabililty as Y-matrix, were developed. The scores of the 4 test batches were used to examine the predictive ability of the model. Copyright © 2011 Elsevier B.V. All rights reserved.

Investigations on humic acid removal from water using surfactant-modified zeolite as adsorbent in a fixed-bed reactor

NASA Astrophysics Data System (ADS)

Elsheikh, Awad F.; Ahmad, Umi Kalthom; Ramli, Zainab

2017-10-01

Natural organic matter (NOM) is ubiquitous in aquatic environments and has recently become an issue of worldwide concern in drinking water treatment. The major component of NOM is humic acids (HA). In this study, a natural zeolite (mordenite) was modified employing hexadecyltrimethylammonium bromide (HDTMA) to enhance greater efficient sites for sorption of HA. The natural zeolite and surfactant-modified zeolite (SMZ) were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectrometer (FT-IR), N2 Adsorption-desorption isotherms and BET-specific surface area, thermographic analysis, derivative thermographic analysis (TGA-DTA) and Field emission scanning electron microscopy (FESEM). A fixed-bed reactor was used for the removal of HA and the effects of different experimental parameters such as HDTMA loading levels, HA solution flow rate, solution pH and eluent concentration were investigated. The results indicated that the SMZ bed with HDTMA loading of 75% of external cation exchange capacity (ECEC) at a flow rate of 2 BV/h and pH of 10 showed the greatest enhanced removal efficiency of HA while ethanol solutions (25%v/v) with feed flow rate of 2 BV/h were sufficient for complete regeneration of SMZ and desorption of HA. Measurements of surface area of SMZ indicated that a monolayer formation of the surfactant at those conditions allowed the optimum removal of HA.

46 CFR 169.567 - Portable extinguishers.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Minimum size Coast Guard classification Living space and open boats 1 per 1000 cu. ft. of space Halon 1211 of 1301 21/2 pounds Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical 2 pounds Propulsion machinery space with fixed CO2 or halon system 1 Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical...

46 CFR 169.567 - Portable extinguishers.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Minimum size Coast Guard classification Living space and open boats 1 per 1000 cu. ft. of space Halon 1211 of 1301 21/2 pounds Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical 2 pounds Propulsion machinery space with fixed CO2 or halon system 1 Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical...

46 CFR 169.567 - Portable extinguishers.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Minimum size Coast Guard classification Living space and open boats 1 per 1000 cu. ft. of space Halon 1211 of 1301 21/2 pounds Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical 2 pounds Propulsion machinery space with fixed CO2 or halon system 1 Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical...

46 CFR 169.567 - Portable extinguishers.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Minimum size Coast Guard classification Living space and open boats 1 per 1000 cu. ft. of space Halon 1211 of 1301 21/2 pounds Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical 2 pounds Propulsion machinery space with fixed CO2 or halon system 1 Foam 11/4 gallons Carbon dioxide 4 pounds B-I. Dry chemical...

Scale up of fuel ethanol production from sugar beet juice using loofa sponge immobilized bioreactor.

PubMed

Ogbonna, J C; Mashima, H; Tanaka, H

2001-01-01

Production of fuel ethanol from sugar beet juice, using cells immobilized on loofa sponge was investigated. Based on ethanol productivity and ease of cell immobilization, a flocculating yeast strain, Saccharomyces cerevisiae IR2 was selected for ethanol production from sugar beet juice. It was found that raw sugar beet juice was an optimal substrate for ethanol production, requiring neither pH adjustment nor nitrogen source supplement. When compared with a 2 l bubble column bioreactor, mixing was not sufficient in an 8 l bioreactor containing a bed of sliced loofa sponges and consequently, the immobilized cells were not uniformly distributed within the bed. Most of the cells were immobilized in the lower part of the bed and this resulted in decreased ethanol productivity. By using an external loop bioreactor, constructing the fixed bed with cylindrical loofa sponges, dividing the bed into upper, middle and lower sections with approximately 1 cm spaces between them and circulating the broth through the loop during the immobilization, uniform cell distribution within the bed was achieved. Using this method, the system was scaled up to 50 l and when compared with the 2 l bubble column bioreactor, there were no significant differences (P > 0.05) in ethanol productivity and yield. By using external loop bioreactor to immobilize the cells uniformly on the loofa sponge beds, efficient large scale ethanol production systems can be constructed.

Experiment Investigation of the Influencing Factors on Bed Agglomeration During Fluidized-Bed Gasification of Biomass Fuels

NASA Astrophysics Data System (ADS)

Chen, Y. Q.; Chen, H. P.; Yang, H. P.; Wang, X. H.; Zhang, S. H.

With the depleting of fossil fuel and environmental polluting increasing, the utilization of biomass resources caught increasing concern. Biomass gasification in fluidized bed, as one promising technology, developed quickly. However, serious agglomeration was displayed as biomass ash reacted with bed material (silica sand) at higher temperature. It hindered the wide utilization of CFB gasifier. The objective ofthis work is to investigate the agglomeration behavior between biomass ash and silica sand, and catch the inherent mechanism. Firstly, the influence of ash compounds on the agglomeration behavior was analyzed with biomass ash and synthesis ash compounds addition in fixed bed as ash sample mixed with bed material evenly before every trial. The reaction temperature was set 850°C that is the operated temperature for many fluidized bed gasificated biomass fuels. Then the influence of reaction time was analyzed. The characteristics of the agglomerated silica sand particles were analyzed by the XRD. Finally, it was simulated with HSC computer mode based on thermodynamic equilibrium. It was observed that when the ratio of the biomass ash to the silica sand was above 0.2, the agglomeration was observed. With the increase of the reaction time, more silica sand particles agglomerated with the biomass ash. There are two kinds of silicate eutecticum investigated by the XRD. It is of great significance for the running ofCFB biomass gasifier and the development ofbiomass utilization technology.

Modelling and simulation of wood chip combustion in a hot air generator system.

PubMed

Rajika, J K A T; Narayana, Mahinsasa

2016-01-01

This study focuses on modelling and simulation of horizontal moving bed/grate wood chip combustor. A standalone finite volume based 2-D steady state Euler-Euler Computational Fluid Dynamics (CFD) model was developed for packed bed combustion. Packed bed combustion of a medium scale biomass combustor, which was retrofitted from wood log to wood chip feeding for Tea drying in Sri Lanka, was evaluated by a CFD simulation study. The model was validated by the experimental results of an industrial biomass combustor for a hot air generation system in tea industry. Open-source CFD tool; OpenFOAM was used to generate CFD model source code for the packed bed combustion and simulated along with an available solver for free board region modelling in the CFD tool. Height of the packed bed is about 20 cm and biomass particles are assumed to be spherical shape with constant surface area to volume ratio. Temperature measurements of the combustor are well agreed with simulation results while gas phase compositions have discrepancies. Combustion efficiency of the validated hot air generator is around 52.2 %.

Impact of a fixed price system on the supply of institutional long-term care: a comparative study of Japanese and German metropolitan areas.

PubMed

Yoshida, Keiko; Kawahara, Kazuo

2014-02-01

The need for institutional long-term care is increasing as the population ages and the pool of informal care givers declines. Care services are often limited when funding is controlled publicly. Fees for Japanese institutional care are publicly fixed and supply is short, particularly in expensive metropolitan areas. Those insured by universal long-term care insurance (LTCI) are faced with geographically inequitable access. The aim of this study was to examine the impact of a fixed price system on the supply of institutional care in terms of equity. The data were derived from official statistics sources in both Japan and Germany, and a self-administered questionnaire was used in Japan in 2011. Cross-sectional multiple regression analyses were used to examine factors affecting bed supply of institutional/residential care in fixed price and free prices systems in Tokyo (Japan), and an individually-bargained price system in North Rhine-Westphalia (Germany). Variables relating to costs and needs were used to test hypotheses of cost-dependency and need-orientation of bed supply in each price system. Analyses were conducted using data both before and after the introduction of LTCI, and the results of each system were qualitatively compared. Total supply of institutional care in Tokyo under fixed pricing was found to be cost-dependent regarding capital costs and scale economies, and negatively related to need. These relationships have however weakened in recent years, possibly caused by political interventions under LTCI. Supply of residential care in Tokyo under free pricing was need-oriented and cost-dependent only regarding scale economies. Supply in North Rhine-Westphalia under individually bargained pricing was cost-independent and not negatively related to need. Findings suggest that publicly funded fixed prices have a negative impact on geographically equitable supply of institutional care. The contrasting results of the non-fixed-price systems for Japanese residential care and German institutional care provide further theoretical supports for this and indicate possible solutions against inequitable supply.

Impact of a fixed price system on the supply of institutional long-term care: a comparative study of Japanese and German metropolitan areas

PubMed Central

2014-01-01

Background The need for institutional long-term care is increasing as the population ages and the pool of informal care givers declines. Care services are often limited when funding is controlled publicly. Fees for Japanese institutional care are publicly fixed and supply is short, particularly in expensive metropolitan areas. Those insured by universal long-term care insurance (LTCI) are faced with geographically inequitable access. The aim of this study was to examine the impact of a fixed price system on the supply of institutional care in terms of equity. Methods The data were derived from official statistics sources in both Japan and Germany, and a self-administered questionnaire was used in Japan in 2011. Cross-sectional multiple regression analyses were used to examine factors affecting bed supply of institutional/residential care in fixed price and free prices systems in Tokyo (Japan), and an individually-bargained price system in North Rhine-Westphalia (Germany). Variables relating to costs and needs were used to test hypotheses of cost-dependency and need-orientation of bed supply in each price system. Analyses were conducted using data both before and after the introduction of LTCI, and the results of each system were qualitatively compared. Results Total supply of institutional care in Tokyo under fixed pricing was found to be cost-dependent regarding capital costs and scale economies, and negatively related to need. These relationships have however weakened in recent years, possibly caused by political interventions under LTCI. Supply of residential care in Tokyo under free pricing was need-oriented and cost-dependent only regarding scale economies. Supply in North Rhine-Westphalia under individually bargained pricing was cost-independent and not negatively related to need. Conclusions Findings suggest that publicly funded fixed prices have a negative impact on geographically equitable supply of institutional care. The contrasting results of the non-fixed-price systems for Japanese residential care and German institutional care provide further theoretical supports for this and indicate possible solutions against inequitable supply. PMID:24485330

Locally produced natural conditioners for dewatering of faecal sludge

PubMed Central

Gold, Moritz; Dayer, Pauline; Faye, Marie Christine Amie Sene; Clair, Guillaume; Seck, Alsane; Niang, Seydou; Morgenroth, Eberhard; Strande, Linda

2016-01-01

ABSTRACT In urban areas of low-income countries, treatment of faecal sludge (FS) is insufficient or non-existent. This results in large amounts of FS being dumped into the environment. Existing treatment technologies for FS, such as settling-thickening tanks and drying beds, are land intensive which is limiting in urban areas. Enhanced settling and dewatering by conditioning was evaluated in order to reduce the treatment footprint (or increase treatment capacity). Conventional wastewater conditioners, such as commercially available lime and polymers, are expensive, and commonly rely on complex supply chains for use in low-income countries. Therefore, the treatment performance of five conditioners which could be produced locally was evaluated: Moringa oleifera seeds and press cake, Jatropha curcas seeds, Jatropha Calotropis leaves and chitosan. M. oleifera seeds and press cake, and chitosan improved settling and dewatering and had a similar performance compared to lime and polymers. Optimal dosages were 400–500 kg M. oleifera/t TS, 300–800 kg lime/t TS and 25–50 kg polymer solution/t TS. In comparison, chitosan required 1.5–3.75 kg/t TS. These dosages are comparable to those recommended for wastewater (sludge). The results indicate that conditioning of FS can reduce total suspended solids (TSS) in the effluent of settling-thickening tanks by 22–81% and reduce dewatering time with drying beds by 59–97%. This means that the area of drying beds could be reduced by 59–97% with end-use as soil conditioner, or 9–26% as solid fuel. Least expensive options and availability will depend on the local context. In Dakar, Senegal, chitosan produced from shrimp waste appears to be most promising. PMID:26984372

Locally produced natural conditioners for dewatering of faecal sludge.

PubMed

Gold, Moritz; Dayer, Pauline; Faye, Marie Christine Amie Sene; Clair, Guillaume; Seck, Alsane; Niang, Seydou; Morgenroth, Eberhard; Strande, Linda

2016-11-01

In urban areas of low-income countries, treatment of faecal sludge (FS) is insufficient or non-existent. This results in large amounts of FS being dumped into the environment. Existing treatment technologies for FS, such as settling-thickening tanks and drying beds, are land intensive which is limiting in urban areas. Enhanced settling and dewatering by conditioning was evaluated in order to reduce the treatment footprint (or increase treatment capacity). Conventional wastewater conditioners, such as commercially available lime and polymers, are expensive, and commonly rely on complex supply chains for use in low-income countries. Therefore, the treatment performance of five conditioners which could be produced locally was evaluated: Moringa oleifera seeds and press cake, Jatropha curcas seeds, Jatropha Calotropis leaves and chitosan. M. oleifera seeds and press cake, and chitosan improved settling and dewatering and had a similar performance compared to lime and polymers. Optimal dosages were 400-500 kg M. oleifera/t TS, 300-800 kg lime/t TS and 25-50 kg polymer solution/t TS. In comparison, chitosan required 1.5-3.75 kg/t TS. These dosages are comparable to those recommended for wastewater (sludge). The results indicate that conditioning of FS can reduce total suspended solids (TSS) in the effluent of settling-thickening tanks by 22-81% and reduce dewatering time with drying beds by 59-97%. This means that the area of drying beds could be reduced by 59-97% with end-use as soil conditioner, or 9-26% as solid fuel. Least expensive options and availability will depend on the local context. In Dakar, Senegal, chitosan produced from shrimp waste appears to be most promising.

Column dynamic studies and breakthrough curve analysis for Cd(II) and Cu(II) ions adsorption onto palm oil boiler mill fly ash (POFA).

PubMed

Aziz, Abdul Shukor Abdul; Manaf, Latifah Abd; Man, Hasfalina Che; Kumar, Nadavala Siva

2014-01-01

This paper investigates the adsorption characteristics of palm oil boiler mill fly ash (POFA) derived from an agricultural waste material in removing Cd(II) and Cu(II) from aqueous solution via column studies. The performance of the study is described through the breakthrough curves concept under relevant operating conditions such as column bed depths (1, 1.5, and 2 cm) and influent metal concentrations (5, 10, and 20 mg/L). The Cd(II) and Cu(II) uptake mechanism is particularly bed depth- and concentration-dependant, favoring higher bed depth and lower influent metal concentration. The highest bed capacity of 34.91 mg Cd(II)/g and 21.93 mg Cu(II)/g of POFA was achieved at 20 mg/L of influent metal concentrations, column bed depth of 2 cm, and flow rate of 5 mL/min. The whole breakthrough curve simulation for both metal ions were best described using the Thomas and Yoon–Nelson models, but it is apparent that the initial region of the breakthrough for Cd(II) was better described using the BDST model. The results illustrate that POFA could be utilized effectively for the removal of Cd(II) and Cu(II) ions from aqueous solution in a fixed-bed column system.

Freestall maintenance: effects on lying behavior of dairy cattle.

PubMed

Drissler, M; Gaworski, M; Tucker, C B; Weary, D M

2005-07-01

In a series of 3 experiments, we documented how sand-bedding depth and distribution changed within freestalls after new bedding was added and the effect of these changes on lying behavior. In experiment 1, we measured changes in bedding depth over a 10-d period at 43 points in 24 freestalls. Change in depth of sand was the greatest the day after new sand was added and decreased over time. Over time, the stall surface became concave, and the deepest part of the stall was at the center. Based on the results of experiment 1, we measured changes in lying behavior when groups of cows had access to freestalls with sand bedding that was 0, 3.5, 5.2, or 6.2 cm at the deepest point, below the curb, while other dimensions remained fixed. We found that daily lying time was 1.15 h shorter in stalls with the lowest levels of bedding compared with stalls filled with bedding. Indeed, for every 1-cm decrease in bedding, cows spent 11 min less time lying down during each 24-h period. In a third experiment, we imposed 4 treatments that reflected the variation in sand depth within stalls: 0, 6.2, 9.9, and 13.7 cm below the curb. Again, lying times reduced with decreasing bedding, such that cows using the stalls with the least amount of bedding (13.7 cm below curb) spent 2.33 h less time per day lying down than when housed with access to freestalls filled with sand (0 cm below curb).

The association between bedding material and the bacterial counts of Staphylococcus aureus, Streptococcus uberis and coliform bacteria on teat skin and in teat canals in lactating dairy cattle.

PubMed

Paduch, Jan-Hendrik; Mohr, Elmar; Krömker, Volker

2013-05-01

Several mastitis-causing pathogens are able to colonize the bovine teat canal. The objective of this study was to investigate the association between the treatment of sawdust bedding with a commercial alkaline conditioner and the bacterial counts on teat skin and in the teat canal. The study used a crossover design. Ten lactating Holstein cows that were free of udder infections and mastitis were included in the study. The animals were bedded on either untreated sawdust or sawdust that had been treated with a hydrated lime-based conditioner. Once a day, fresh bedding material was added. After 3 weeks, the bedding material was removed from the cubicles, fresh bedding material was provided, and the cows were rotated between the two bedding material groups. Teat skin and teat canals were sampled using the wet and dry swab technique after weeks 1, 2, 3, 4, 5 and 6. Staphylococcus aureus, Streptococcus uberis, Escherichia coli and other coliform bacteria were detected in the resulting agar plate cultures. The treatment of the bedding material was associated with the teat skin bacterial counts of Str. uberis, Esch. coli and other coliform bacteria. An association was also found between the bedding material and the teat canal bacterial counts of coliform bacteria other than Esch. coli. For Staph. aureus, no associations with the bedding material were found. In general, the addition of a hydrated lime-based conditioner to sawdust reduces the population sizes of environmental pathogens on teat skin and in teat canals.

Process for the preparation of cumene

DOEpatents

Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

1991-01-01

Cumene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic by feeding propylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with propylene, thereby reacting substantially all of the propylene and recovering benzene as the principal overhead and cumene and diisopropyl benzene in the bottoms. The bottoms are fractionated, the cumene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diisopropyl benzene to cumene which is again separated and recovered.

Process for the preparation of cumene

DOEpatents

Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

1991-10-08

Cumene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50 C to 500 C, using as the catalyst a molecular sieve characterized as acidic by feeding propylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with propylene, thereby reacting substantially all of the propylene and recovering benzene as the principal overhead and cumene and diisopropyl benzene in the bottoms. The bottoms are fractionated, the cumene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diisopropyl benzene to cumene which is again separated and recovered. 2 figures.

Process for the preparation of ethyl benzene

DOEpatents

Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

1995-12-19

Ethyl benzene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50 C to 300 C, using as the catalyst a mole sieve characterized as acidic by feeding ethylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene and diethyl benzene in the bottoms. The bottoms are fractionated, the ethyl benzene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diethyl benzene to ethyl benzene which is again separated and recovered. 2 figs.

Process for the preparation of ethyl benzene

DOEpatents

Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

1995-01-01

Ethyl benzene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 50.degree. C. to 300.degree. C., using as the catalyst a mole sieve characterized as acidic by feeding ethylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene and diethyl benzene in the bottoms. The bottoms are fractionated, the ethyl benzene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diethyl benzene to ethyl benzene which is again separated and recovered.

Incipient Motion of Sand and Oil Agglomerates

NASA Astrophysics Data System (ADS)

Nelson, T. R.; Dalyander, S.; Jenkins, R. L., III; Penko, A.; Long, J.; Frank, D. P.; Braithwaite, E. F., III; Calantoni, J.

2016-12-01

Weathered oil mixed with sediment in the surf zone in the northern Gulf of Mexico after the 2010 Deepwater Horizon oil spill, forming large mats of sand and oil. Wave action fragmented the mats into sand and oil agglomerates (SOAs) with diameters of about 1 to 10 cm. These SOAs were transported by waves and currents along the Gulf Coast, and have been observed on beaches for years following the spill. SOAs are composed of 70%-95% sand by mass, with an approximate density of 2107 kg/m³. To measure the incipient motion of SOAs, experiments using artificial SOAs were conducted in the Small-Oscillatory Flow Tunnel at the U.S. Naval Research Laboratory under a range of hydrodynamic forcing. Spherical and ellipsoidal SOAs ranging in size from 0.5 to 10 cm were deployed on a fixed flat bed, a fixed rippled bed, and a movable sand bed. In the case of the movable sand bed, SOAs were placed both proud and partially buried. Motion was tracked with high-definition video and with inertial measurement units embedded in some of the SOAs. Shear stress and horizontal pressure gradients, estimated from velocity measurements made with a Nortek Vectrino Profiler, were compared with observed mobility to assess formulations for incipient motion. For SOAs smaller than 1 cm in diameter, incipient motion of spherical and ellipsoidal SOAs was consistent with predicted critical stress values. The measured shear stress at incipient motion of larger, spherical SOAs was lower than predicted, indicating an increased dependence on the horizontal pressure gradient. In contrast, the measured shear stress required to move ellipsoidal SOAs was higher than predicted, even compared to values modified for larger particles in mixed-grain riverine environments. The laboratory observations will be used to improve the prediction of incipient motion, transport, and seafloor interaction of SOAs.

Evaluation of a clay-based acidic bedding conditioner for dairy cattle bedding.

PubMed

Proietto, R L; Hinckley, L S; Fox, L K; Andrew, S M

2013-02-01

This study investigated the effects of a clay-based acidic bedding conditioner on sawdust bedding pH, dry matter (DM), environmental pathogen counts, and environmental bacterial counts on teat ends of lactating dairy cows. Sixteen lactating Holstein cows were paired based on parity, days in milk, milk yield, and milk somatic cell count, and were negative for the presence of an intramammary pathogen. Within each pair, cows were randomly assigned to 1 of 2 treatments with 3-wk periods in a crossover design. Treatment groups consisted of 9 freestalls per group bedded with either untreated sawdust or sawdust with a clay-based acidic bedding conditioner, added at 3- to 4-d intervals over each 21-d period. Bedding and teat ends were aseptically sampled on d 0, 1, 2, 7, 14, and 21 for determination of environmental bacterial counts. At the same time points, bedding was sampled for DM and pH determination. The bacteria identified in the bedding material were total gram-negative bacteria, Streptococcus spp., and coliform bacteria. The bacteria identified on the teat ends were Streptococcus spp., coliform bacteria, and Klebsiella spp. Teat end score, milk somatic cell count, and intramammary pathogen presence were measured weekly. Bedding and teat cleanliness, environmental high and low temperatures, and dew point data were collected daily. The bedding conditioner reduced the pH, but not the DM, of the sawdust bedding compared with untreated sawdust. Overall environmental bacterial counts in bedding were lower for treated sawdust. Total bacterial counts in bedding and on teat ends increased with time over both periods. Compared with untreated sawdust, the treated bedding had lower counts of total gram-negative bacteria and streptococci, but not coliform counts. Teat end bacterial counts were lower for cows bedded on treated sawdust for streptococci, coliforms, and Klebsiella spp. compared with cows bedded on untreated sawdust. The clay-based acidic bedding conditioner reduced environmental pathogens in sawdust bedding and teat ends without affecting teat end integrity. Copyright © 2013 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Depositional environments of some Pleistocene coastal terrace deposits, southwestern Oregon - case history of progradational beach and dune sequence.

USGS Publications Warehouse

Hunter, R.E.

1980-01-01

These deposits comprise a basal gravelly unit and 3 overlying sandy units, each with mud beds, a paleosol, or the modern soil in its uppermost part. The gravelly unit is interpreted as a progradational deposit. The main parts of the sandy units are made up of 1) a crossbedded sand facies, the dominant structure in which is medium-scale crossbedding (interpreted as the product of small eolian dunes), and 2) an irregularly bedded sand facies, which is locally pebbly and is dominated by scour-and-fill structures, interpreted as deposits of interdune ephemeral streams, ephemeral ponds, and wet to dry subaerial flats. The mud beds and paleosols represent times of temporary stabilization of the dune field.- from Author

A New Dry Flue Gas Desulfurization Process-Underfeed Circulating Spouted Bed

NASA Astrophysics Data System (ADS)

Tao, M.; Jin, B. S.; Yang, Y. P.

Applying an underfeed system, the underfeed circulating spouted bed was designed as a desulfurization reactor. The main objective of the technology is to improve the mixing effect and distribution uniformity of solid particles, and therefore to advance the desulfurization efficiency and calcium utility. In this article, a series of experimental studies were conducted to investigate the fluidization behavior of the solid-gas two-phase flow in the riser. The results show that the technology can distinctly improve the distribution of gas velocity and particle flux on sections compared with the facefeed style. Analysis of pressure fluctuation signals indicates that the operation parameters have significant influence on the flow field in the reaction bed. The existence of injecting flow near the underfeed nozzle has an evident effect on strengthening the particle mixing.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mehta, Y.; Neal, C.; Salari, K.

Propagation of a strong shock through a bed of particles results in complex wave dynamics such as a reflected shock, a transmitted shock, and highly unsteady flow inside the particle bed. In this paper we present three-dimensional numerical simulations of shock propagation in air over a random bed of particles. We assume the flow is inviscid and governed by the Euler equations of gas dynamics. Simulations are carried out by varying the volume fraction of the particle bed at a fixed shock Mach number. We compute the unsteady inviscid streamwise and transverse drag coefficients as a function of time formore » each particle in the random bed as a function of volume fraction. We show that (i) there are significant variations in the peak drag for the particles in the bed, (ii) the mean peak drag as a function of streamwise distance through the bed decreases with a slope that increases as the volume fraction increases, and (iii) the deviation from the mean peak drag does not correlate with local volume fraction. We also present the local Mach number and pressure contours for the different volume fractions to explain the various observed complex physical mechanisms occurring during the shock-particle interactions. Since the shock interaction with the random bed of particles leads to transmitted and reflected waves, we compute the average flow properties to characterize the strength of the transmitted and reflected shock waves and quantify the energy dissipation inside the particle bed. Finally, to better understand the complex wave dynamics in a random bed, we consider a simpler approximation of a planar shock propagating in a duct with a sudden area change. We obtain Riemann solutions to this problem, which are used to compare with fully resolved numerical simulations.« less

Ames Air Revitalization

NASA Technical Reports Server (NTRS)

Huang, Roger Z.

2015-01-01

This is an informal presentation presented to the University of Colorado, Boulder Bioastronautics group seminar. It highlights the key focal areas of the Air Revitalization Group research over the past year, including progress on the CO2 Removal and Compression System, testing of CDRA drying bed configurations, and adsorption research.