Enzymatic regulation of organic acid metabolism in an alkali-tolerant ...

African Journals Online (AJOL)

Tuoyo Aghomotsegin

2016-10-05

Oct 5, 2016 ... seedlings of C. virgata were treated with varying salt and alkali stress. First, the composition and .... mechanisms of organic acid accumulation in C. virgata ..... dehydrogenase and ferredoxin-dependent glutamate synthase in.

Comparison of bile acid synthesis determined by isotope dilution versus fecal acidic sterol output in human subjects

International Nuclear Information System (INIS)

Duane, W.C.; Holloway, D.E.; Hutton, S.W.; Corcoran, P.J.; Haas, N.A.

1982-01-01

Fecal acidic sterol output has been found to be much lower than bile acid synthesis determined by isotope dilution. Because of this confusing discrepancy, we compared these 2 measurements done simultaneously on 13 occasions in 5 normal volunteers. In contrast to previous findings, bile acid synthesis by the Lindstedt isotope dilution method averaged 16.3% lower than synthesis simultaneously determined by fecal acidic sterol output (95% confidence limit for the difference - 22.2 to -10.4%). When one-sample determinations of bile acid pools were substituted for Lindstedt pools, bile acid synthesis by isotope dilution averaged 5.6% higher than synthesis by fecal acidic sterol output (95% confidence limits -4.9 to 16.1%). These data indicate that the 2 methods yield values in reasonably close agreement with one another. If anything, fecal acidic sterol outputs are slightly higher than synthesis by isotope dilution

PRODUCTION OF TRIFLUOROACETIC ACID COMPOUNDS

Science.gov (United States)

Haworth, W.N.; Stacey, M.

1949-08-30

A process is described for the preparation of trifluoroacetic acid. Acetone vapor diluted wlth nitrogen and fluorine also diluted with nltrogen are fed separately at a temperature of about 210 deg C into a reaction vessel containing a catalyst mass selected from-the group consisting of silver and gold. The temperature in the reaction vessel is maintained in the range of 200 deg to 250 deg C. The reaction product, trifluoroacetyl fluoride, is absorbed in aqueous alkali solution. Trifluoroacetic acid is recovered from the solution by acidification wlth an acid such as sulfuric followed by steam distillation.

Alkali Metal Ion Complexes with Phosphates, Nucleotides, Amino Acids, and Related Ligands of Biological Relevance. Their Properties in Solution.

Science.gov (United States)

Crea, Francesco; De Stefano, Concetta; Foti, Claudia; Lando, Gabriele; Milea, Demetrio; Sammartano, Silvio

2016-01-01

Alkali metal ions play very important roles in all biological systems, some of them are essential for life. Their concentration depends on several physiological factors and is very variable. For example, sodium concentrations in human fluids vary from quite low (e.g., 8.2 mmol dm(-3) in mature maternal milk) to high values (0.14 mol dm(-3) in blood plasma). While many data on the concentration of Na(+) and K(+) in various fluids are available, the information on other alkali metal cations is scarce. Since many vital functions depend on the network of interactions occurring in various biofluids, this chapter reviews their complex formation with phosphates, nucleotides, amino acids, and related ligands of biological relevance. Literature data on this topic are quite rare if compared to other cations. Generally, the stability of alkali metal ion complexes of organic and inorganic ligands is rather low (usually log K  Na(+) > K(+) > Rb(+) > Cs(+). For example, for citrate it is: log K ML = 0.88, 0.80, 0.48, 0.38, and 0.13 at 25 °C and infinite dilution. Some considerations are made on the main aspects related to the difficulties in the determination of weak complexes. The importance of the alkali metal ion complexes was also studied in the light of modelling natural fluids and in the use of these cations as probes for different processes. Some empirical relationships are proposed for the dependence of the stability constants of Na(+) complexes on the ligand charge, as well as for correlations among log K values of NaL, KL or LiL species (L = generic ligand).

Microbial reverse-electrodialysis chemical-production cell for acid and alkali production

KAUST Repository

Zhu, Xiuping; Hatzell, Marta C.; Cusick, Roland D.; Logan, Bruce E.

2013-01-01

A new type of bioelectrochemical system, called a microbial reverse-electrodialysis chemical-production cell (MRCC), was developed to produce acid and alkali using energy derived from organic matter (acetate) and salinity gradients (NaCl solutions

Interaction Studies of Dilute Aqueous Oxalic Acid

Directory of Open Access Journals (Sweden)

Kiran Kandpal

2007-01-01

Full Text Available Molecular conductance λm, relative viscosity and density of oxalicacid at different concentration in dilute aqueous solution were measured at 293 K.The conductance data were used to calculate the value association constant.Viscosity and density data were used to calculate the A and B coefficient ofJone-Dole equation and apparent molar volume respectively. The viscosityresults were utilized for the applicability of Modified Jone-Dole equation andStaurdinger equations. Mono oxalate anion acts, as structure maker and thesolute-solvent interaction were present in the dilute aqueous oxalic acid.

Optimisation of Dilute Sulphuric Acid Hydrolysis of Waste ...

African Journals Online (AJOL)

Dilute sulphuric acid hydrolysis of waste paper was investigated in this study. The effects of acid concentration, time, temperature and liquid to solid ratio on the total reducing sugar concentration were studied over three levels using a four variable Box-Behnken design (BBD). A statistical model was developed for the ...

Alkali production associated with malolactic fermentation by oral streptococci and protection against acid, oxidative, or starvation damage.

Science.gov (United States)

Sheng, Jiangyun; Baldeck, Jeremiah D; Nguyen, Phuong T M; Quivey, Robert G; Marquis, Robert E

2010-07-01

Alkali production by oral streptococci is considered important for dental plaque ecology and caries moderation. Recently, malolactic fermentation (MLF) was identified as a major system for alkali production by oral streptococci, including Streptococcus mutans. Our major objectives in the work described in this paper were to further define the physiology and genetics of MLF of oral streptococci and its roles in protection against metabolic stress damage. L-Malic acid was rapidly fermented to L-lactic acid and CO(2) by induced cells of wild-type S. mutans, but not by deletion mutants for mleS (malolactic enzyme) or mleP (malate permease). Mutants for mleR (the contiguous regulator gene) had intermediate capacities for MLF. Loss of capacity to catalyze MLF resulted in loss of capacity for protection against lethal acidification. MLF was also found to be protective against oxidative and starvation damage. The capacity of S. mutans to produce alkali from malate was greater than its capacity to produce acid from glycolysis at low pH values of 4 or 5. MLF acted additively with the arginine deiminase system for alkali production by Streptococcus sanguinis, but not with urease of Streptococcus salivarius. Malolactic fermentation is clearly a major process for alkali generation by oral streptococci and for protection against environmental stresses.

Alkali production associated with malolactic fermentation by oral streptococci and protection against acid, oxidative, or starvation damage

Science.gov (United States)

Sheng, Jiangyun; Baldeck, Jeremiah D.; Nguyen, Phuong T.M.; Quivey, Robert G.; Marquis, Robert E.

2011-01-01

Alkali production by oral streptococci is considered important for dental plaque ecology and caries moderation. Recently, malolactic fermentation (MLF) was identified as a major system for alkali production by oral streptococci, including Streptococcus mutans. Our major objectives in the work described in this paper were to further define the physiology and genetics of MLF of oral streptococci and its roles in protection against metabolic stress damage. l-Malic acid was rapidly fermented to l-lactic acid and CO2 by induced cells of wild-type S. mutans, but not by deletion mutants for mleS (malolactic enzyme) or mleP (malate permease). Mutants for mleR (the contiguous regulator gene) had intermediate capacities for MLF. Loss of capacity to catalyze MLF resulted in loss of capacity for protection against lethal acidification. MLF was also found to be protective against oxidative and starvation damage. The capacity of S. mutans to produce alkali from malate was greater than its capacity to produce acid from glycolysis at low pH values of 4 or 5. MLF acted additively with the arginine deiminase system for alkali production by Streptococcus sanguinis, but not with urease of Streptococcus salivarius. Malolactic fermentation is clearly a major process for alkali generation by oral streptococci and for protection against environmental stresses. PMID:20651853

Investigation of emulsified, acid and acid-alkali catalyzed mesoporous bioactive glass microspheres for bone regeneration and drug delivery

Energy Technology Data Exchange (ETDEWEB)

Miao, Guohou [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 China (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 China (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 China (China); Chen, Xiaofeng, E-mail: chenxf@scut.edu.cn [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 China (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 China (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 China (China); Dong, Hua [National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 China (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 China (China); School of Biological Science and Engineering, South China University of Technology, Guangzhou 510006 (China); Fang, Liming; Mao, Cong; Li, Yuli; Li, Zhengmao; Hu, Qing [School of Materials Science and Engineering, South China University of Technology, Guangzhou 510641 China (China); National Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006 China (China); Guangdong Province Key Laboratory of Biomedical Engineering, South China University of Technology, Guangzhou 510006 China (China)

2013-10-15

Acid-catalyzed mesoporous bioactive glass microspheres (MBGMs-A) and acid-alkali co-catalyzed mesoporous bioactive glass microspheres (MBGMs-B) were successfully synthesized via combination of sol-gel and water-in-oil (W/O) micro-emulsion methods. The structural, morphological and textural properties of mesoporous bioactive glass microspheres (MBGMs) were characterized by various techniques. Results show that both MBGMs-A and MBGMs-B exhibit regularly spherical shape but with different internal porous structures, i.e., a dense microstructure for MBGMs-A and internally porous structure for MBGMs-B. {sup 29}Si NMR data reveal that MGBMs have low polymerization degree of silica network. The in vitro bioactivity tests indicate that the apatite formation rate of MBGMs-B was faster than that of MBGMs-A after soaking in simulated body fluid (SBF) solution. Furthermore, the two kinds of MBGMs have similar storage capacity of alendronate (AL), and the release behaviors of AL could be controlled due to their unique porous structure. In conclusion, the microspheres are shown to be promising candidates as bone-related drug carriers and filling materials of composite scaffold for bone repair. - Graphical abstract: The morphologies and microstructures of acid-catalyzed mesoporous bioactive glass microspheres (MBGMs-A) and acid-alkali co-catalyzed mesoporous bioactive glass microspheres (MBGMs-B) were observed by scanning electron microscope and transmission electron microscope. MBGMs-A exhibits a dense structure and a porous can be observed in MBGMs-B. The microspheres have a quick inducing-apatite formation ability and show a sustained release of alendronate (AL). Highlights: • A rapid method was reported to prepare mesoporous bioactive glass microspheres. • The addition of ammonia significantly shortens the preparation time. • Acid and acid-alkali co-catalyzed microspheres were studied for the first time. • The materials exhibited excellent in vitro bioactivity and

Calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid

International Nuclear Information System (INIS)

Kurbanov, A.R.; Sharipov, D.Sh.

1993-01-01

Present article is devoted to calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid. The calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid was carried out in order to determine the thermal effects of reactions. The results of interaction of Ba(OH) 4 ·8H 2 O with 5, 10, and 20% solution of hydrofluoric acid were considered.

Bioethanol production by cashew apple bagasse (Anacardium occidentale L.): comparison of acid diluted and alkali pre-treatments; Producao de bioetanol a partir da fibra do caju (Anacardium occidentale L.): comparacao entre o pre-tratamento acido e alcalino

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Tigressa H.S.; Pinheiro, Alvaro D.T.; Goncalves, Luciana R.B. [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil); Rocha, Maria V.P.; Macedo, Gorete R. de [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil)

2008-07-01

Due to the growing environmental awareness on the negative impact resulting from utilization of fossil fuels, and in the search for renewable energy sources, biofuels' interest as Bioethanol has rapidly expanded recently. In this context, lignocellulosic compounds have become center of attention as an abundant and economic alternative source of carbohydrates for ethanol production. In this study, cashew's bagasse acid hydrolysis was initially studied for glucose synthesis and its fermentation towards ethanol production. Sulfuric acid concentration, solids concentration and time were some of the factors evaluated. The highest glucose productivity value (162,9 mg.g de bagaco{sup -1}) , was obtained for 0,6 mol.L{sup -1} of sulfuric acid in an autoclave at 121 deg C for 15 min. For the fermentation of the hydrolyzed material by S. cerevisiae containing 16 {+-} 2,0 g.L{sup -1} of glucose metabolic, the yield and productivity obtained were 0,63 g-g glucose{sup -1} and 1,43 g.L{sup -1}h{sup -1} respectively. Ethanol concentration after 6 h of fermentation of this hydrolyzed was 11 g.L{sup -1}. In the best conditions of acid hydrolysis, a second pre-treatment with diluted sulfuric acid was performed to evaluate availability of hemicelluloses at 160 deg C and 180 deg C. For comparative purposes, alkali pre-treatment was evaluated under the conditions of 0,6 mol.L{sup -1}, 30% p/v of bagasse thermically treated at 121 deg C for 15 minutes. However, concentration of sugars was not sufficient for fermentation. Also, nitrogen supplementation of the hydrolyzed fraction did not influence significantly ethanol production. The results demonstrate that the hydrolyzed fraction from the acid pre-treatment of cashew's bagasse could be utilized for ethanol production. (author)

Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk

Directory of Open Access Journals (Sweden)

Rudy Agustriyanto

2012-12-01

Full Text Available Coconut husk is classified as complex lignocellulosic material that contains cellulose, hemicellulose, lignin, and some other extractive compounds. Cellulose from coconut husk can be used as fermentation substrate after enzymatic hydrolysis. In contrary, lignin content from the coconut husk will act as an inhibitor in this hydrolysis process. Therefore, a pretreatment process is needed to enhance the hydrolysis of cellulose. The objective of this research is to investigate the production of the glucose through dilute acid pretreatment and to obtain its optimum operating conditions. In this study, the pretreatment was done using dilute sulfuric acid in an autoclave reactor. The pretreatment condition were varied at 80°C, 100°C, 120°C and 0.9%, 1.2%, 1.5% for temperature and acid concentration respectively. The acid pretreated coconut husk was then hydrolyzed using commercial cellulase (celluclast and β-glucosidase (Novozyme 188. The hydrolysis time was 72 hours and the operating conditions were varied at several temperature and pH. From the experimental results it can be concluded that the delignification temperature variation has greater influence than the acid concentration. The optimum operating condition was obtained at pH 4 and 50°C which was pretreated at 100°C using 1.5% acid concentration. Copyright © 2012 by BCREC UNDIP. All rights reserved. (Selected Paper from International Conference on Chemical and Material Engineering (ICCME 2012Received: 28th September 2012, Revised: 2nd October 2012, Accepted: 4th October 2012[How to Cite: R. Agustriyanto, A. Fatmawati, Y. Liasari. (2012. Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk. Bulletin of Chemical Reaction Engineering & Catalysis, 7(2: 137-141. doi:10.9767/bcrec.7.2.4046.137-141] [How to Link / DOI: http://dx.doi.org/10.9767/bcrec.7.2.4046.137-141 ] | View in 

Enhancing Skin Permeation of Biphenylacetic Acid (BPA) Using Salt Formation with Organic and Alkali Metal Bases

OpenAIRE

PAWAR, Vijay; NAIK, Prashant; GIRIDHAR, Rajani; YADAV, Mange Ram

2014-01-01

In the present study, a series of organic and alkali metal salts of biphenylacetic acid (BPA) have been prepared and evaluated in vitro for percutaneous drug delivery. The physicochemical properties of BPA salts were determined using solubility measurements, DSC, and IR. The DSC thermogram and FTIR spectra confirmed the salt formation with organic and alkali metal bases. Among the series, salts with organic amines (ethanolamine, diethanolamine, triethanol-amine, and diethylamine) had lowered ...

Laboratory studies of 2H evaporator scale dissolution in dilute nitric acid

International Nuclear Information System (INIS)

Oji, L.

2014-01-01

The rate of 2H evaporator scale solids dissolution in dilute nitric acid has been experimentally evaluated under laboratory conditions in the SRNL shielded cells. The 2H scale sample used for the dissolution study came from the bottom of the evaporator cone section and the wall section of the evaporator cone. The accumulation rate of aluminum and silicon, assumed to be the two principal elemental constituents of the 2H evaporator scale aluminosilicate mineral, were monitored in solution. Aluminum and silicon concentration changes, with heating time at a constant oven temperature of 90 deg C, were used to ascertain the extent of dissolution of the 2H evaporator scale mineral. The 2H evaporator scale solids, assumed to be composed of mostly aluminosilicate mineral, readily dissolves in 1.5 and 1.25 M dilute nitric acid solutions yielding principal elemental components of aluminum and silicon in solution. The 2H scale dissolution rate constant, based on aluminum accumulation in 1.5 and 1.25 M dilute nitric acid solution are, respectively, 9.21E-04 ± 6.39E-04 min -1 and 1.07E-03 ± 7.51E-05 min -1 . Silicon accumulation rate in solution does track the aluminum accumulation profile during the first few minutes of scale dissolution. It however diverges towards the end of the scale dissolution. This divergence therefore means the aluminum-to-silicon ratio in the first phase of the scale dissolution (non-steady state conditions) is different from the ratio towards the end of the scale dissolution. Possible causes of this change in silicon accumulation in solution as the scale dissolution progresses may include silicon precipitation from solution or the 2H evaporator scale is a heterogeneous mixture of aluminosilicate minerals with several impurities. The average half-life for the decomposition of the 2H evaporator scale mineral in 1.5 M nitric acid is 12.5 hours, while the half-life for the decomposition of the 2H evaporator scale in 1.25 M nitric acid is 10.8 hours

Effect of temperature on the dilution enthalpies of α,ω-amino acids in aqueous solutions

International Nuclear Information System (INIS)

Romero, C.M.; Cadena, J.C.; Lamprecht, I.

2011-01-01

Highlights: → The dilution of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid in water is an exothermic process at T = (293.15, 298.15, 303.15, and 308.15) K. → The limiting experimental slopes of the enthalpies of dilution with respect to the molality change Δm, are negative suggesting that the solutes interact with water primarily through their alkyl groups. → The value of the pairwise coefficient is positive at the temperatures considered, and the magnitude increases linearly with the number of methylene groups. → The comparison between the pairwise interaction coefficients for α,ω-amino acids and α-amino acids shows that the change in the enthalpic interaction coefficient is related to the relative position of the polar groups. - Abstract: Dilution enthalpies of aqueous solutions of 3-amino propanoic acid, 4-amino butanoic acid, 5-amino pentanoic acid, and 6-amino hexanoic acid were determined at T = (293.15, 298.15, 303.15, and 308.15) K using an LKB flow microcalorimeter. The homotactic interaction coefficients were obtained according to the McMillan-Mayer theory from the experimental data. For all the systems studied, the dilution of α,ω-amino acids in water is an exothermic process; the pair coefficients have positive values which increases with chain length. The obtained values of the interaction coefficients are interpreted in terms of solute-solvent and solute-solute interactions and are used as indicative of hydrophobic behavior of the amino acid studied.

Acids and Alkalis. Seychelles Integrated Science. [Teacher and Pupil Booklets]. Unit 9.

Science.gov (United States)

Brophy, M.; Fryars, M.

Seychelles Integrated Science (SIS), a 3-year laboratory-based science program for students (ages 11-15) in upper primary grades 7, 8, and 9, was developed from an extensive evaluation and modification of previous P7-P9 materials. This P8 SIS unit focuses on: (1) the uses of acids and bases (alkalis) in students' everyday lives, stressing their…

Simultaneous saccharification and co-fermentation of peracetic acid pretreated sugar cane bagasse

Energy Technology Data Exchange (ETDEWEB)

Teixeira, L.C. [Fundacao Centro Tecnologico de Minas Gerais, Belo Horizonte (Brazil); Linden, J.C.; Schroeder, H.A. [Colorado State University, Fort Collins, CO (United States)

1999-07-01

Previous work in our laboratory has demonstrated that peracetic acid improves the enzymatic digestibility of lignocellulosic materials. From the same studies, use of dilute alkali solutions as a pre-pretreatment prior to peracetic acid lignin oxidation increases sugar conversion yields in a synergistic, not additive, manner. Deacetylation of xylan is conducted easily by use of dilute alkali solutions at mild conditions. In this paper, the effectiveness of peracetic acid pretreatment of sugar cane bagasse combined with an alkaline pre-pretreatment, is evaluated through simultaneous saccharification and co-fermentation (SSCF) procedures. A practical 92% of theoretical ethanol yield using recombinant Zymomonas mobilis CP4/pZB5 is achieved using 6% NaOH/I5% peracetic acid pretreated substrate. No sugar accumulation is observed during SSCF; the recombinant microorganism exhibits greater glucose utilization rates than those of xylose. Acetate levels at the end of the co-fermentations are less than 0.2% (w/v). Based on demonstrated reduction of acetyl groups of the biomass, alkaline pre-pretreatments help to reduce peracetic acid requirements. The influence of deacetylation is more pronounced in combined pretreatments using lower peracetic acid loadings. Stereochemical impediments of the acetyl groups in hemicellulase on the activity of specific enzymes may be involved. (author)

Elucidating the role of ferrous ion cocatalyst in enhancing dilute acid pretreatment of lignocellulosic biomass

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Wei Hui

2011-11-01

Full Text Available Abstract Background Recently developed iron cocatalyst enhancement of dilute acid pretreatment of biomass is a promising approach for enhancing sugar release from recalcitrant lignocellulosic biomass. However, very little is known about the underlying mechanisms of this enhancement. In the current study, our aim was to identify several essential factors that contribute to ferrous ion-enhanced efficiency during dilute acid pretreatment of biomass and to initiate the investigation of the mechanisms that result in this enhancement. Results During dilute acid and ferrous ion cocatalyst pretreatments, we observed concomitant increases in solubilized sugars in the hydrolysate and reducing sugars in the (insoluble biomass residues. We also observed enhancements in sugar release during subsequent enzymatic saccharification of iron cocatalyst-pretreated biomass. Fourier transform Raman spectroscopy showed that major peaks representing the C-O-C and C-H bonds in cellulose are significantly attenuated by iron cocatalyst pretreatment. Imaging using Prussian blue staining indicated that Fe2+ ions associate with both cellulose/xylan and lignin in untreated as well as dilute acid/Fe2+ ion-pretreated corn stover samples. Analyses by scanning electron microscopy and transmission electron microscopy revealed structural details of biomass after dilute acid/Fe2+ ion pretreatment, in which delamination and fibrillation of the cell wall were observed. Conclusions By using this multimodal approach, we have revealed that (1 acid-ferrous ion-assisted pretreatment increases solubilization and enzymatic digestion of both cellulose and xylan to monomers and (2 this pretreatment likely targets multiple chemistries in plant cell wall polymer networks, including those represented by the C-O-C and C-H bonds in cellulose.

Dilute oxalic acid pretreatment for biorefining giant reed (Arundo donax L.)

Science.gov (United States)

Danilo Scordia; Salvatore L. Cosentino; Jae-Won Lee; Thomas W. Jeffries

2011-01-01

Biomass pretreatment is essential to overcome recalcitrance of lignocellulose for ethanol production. In the present study we pretreated giant reed (Arundo donax L.), a perennial, rhizomatous lignocellulosic grass with dilute oxalic acid. The effects of temperature (170-190 ºC), acid loading (2-10% w/w) and reaction time (15-40 min) were handled as a single...

Controlled in-situ dissolution of an alkali metal

Science.gov (United States)

Jones, Jeffrey Donald; Dooley, Kirk John; Tolman, David Donald

2012-09-11

A method for the controllable dissolution of one or more alkali metals from a vessel containing a one or more alkali metals and/or one or more partially passivated alkali metals. The vessel preferably comprising a sodium, NaK or other alkali metal-cooled nuclear reactor that has been used. The alkali metal, preferably sodium, potassium or a combination thereof, in the vessel is exposed to a treatment liquid, preferably an acidic liquid, more preferably citric acid. Preferably, the treatment liquid is maintained in continuous motion relative to any surface of unreacted alkali metal with which the treatment liquid is in contact. The treatment liquid is preferably pumped into the vessel containing the one or more alkali metals and the resulting fluid is extracted and optionally further processed. Preferably, the resulting off-gases are processed by an off-gas treatment system and the resulting liquids are processed by a liquid disposal system. In one preferred embodiment, an inert gas is pumped into the vessel along with the treatment liquid.

Discriminating Properties of Alkali Metal Ions Towards the Constituents of Proteins and Nucleic Acids. Conclusions from Gas-Phase and Theoretical Studies.

Science.gov (United States)

Rodgers, Mary T; Armentrout, Peter B

2016-01-01

Quantitative insight into the structures and thermodynamics of alkali metal cations interacting with biological molecules can be obtained from studies in the gas phase combined with theoretical work. In this chapter, the fundamentals of the experimental and theoretical techniques are first summarized and results for such work on complexes of alkali metal cations with amino acids, small peptides, and nucleobases are reviewed. Periodic trends in how these interactions vary as the alkali metal cations get heavier are highlighted.

Formation of lysinoalanine in egg white under alkali treatment.

Science.gov (United States)

Zhao, Yan; Luo, Xuying; Li, Jianke; Xu, Mingsheng; Tu, Yonggang

2016-03-01

To investigate the formation mechanism of lysinoalanine (LAL) in eggs during the alkali treatment process, NaOH was used for the direct alkali treatment of egg white, ovalbumin, and amino acids; in addition, the amount of LAL formed during the alkali treatment process was measured. The results showed that the alkali treatment resulted in the formation of LAL in the egg white. The LAL content increased with increasing pH and temperature, with the LAL content first increasing and then leveling off with increasing time. The amount of LAL formed in the ovalbumin under the alkali treatment condition accounted for approximately 50.51% to 58.68% of the amount of LAL formed in the egg white. Thus, the LAL formed in the ovalbumin was the main source for the LAL in the egg white during the alkali treatment process. Under the alkali treatment condition, free L-serine, L-cysteine, and L-cystine reacted with L-lysine to form LAL; therefore, they are the precursor amino acids of LAL formed in eggs during the alkali treatment process. © 2016 Poultry Science Association Inc.

The effect of dilute acid pre-treatment process in bioethanol production from durian (Durio zibethinus) seeds waste

Science.gov (United States)

Ghazali, K. A.; Salleh, S. F.; Riayatsyah, T. M. I.; Aditiya, H. B.; Mahlia, T. M. I.

2016-03-01

Lignocellulosic biomass is one of the promising feedstocks for bioethanol production. The process starts from pre-treatment, hydrolysis, fermentation, distillation and finally obtaining the final product, ethanol. The efficiency of enzymatic hydrolysis of cellulosic biomass depends heavily on the effectiveness of the pre-treatment step which main function is to break the lignin structure of the biomass. This work aims to investigate the effects of dilute acid pre-treatment on the enzymatic hydrolysis of durian seeds waste to glucose and the subsequent bioethanol fermentation process. The yield of glucose from dilute acid pre-treated sample using 0.6% H2SO4 and 5% substrate concentration shows significant value of 23.4951 g/L. Combination of dilute acid pre-treatment and enzymatic hydrolysis using 150U of enzyme able to yield 50.0944 g/L of glucose content higher compared to normal pre-treated sample of 8.1093 g/L. Dilute acid pre-treatment sample also shows stable and efficient yeast activity during fermentation process with lowest glucose content at 2.9636 g/L compared to 14.7583g/L for normal pre-treated sample. Based on the result, it can be concluded that dilute acid pre-treatment increase the yield of ethanol from bioethanol production process.

Enhancing Skin Permeation of Biphenylacetic Acid (BPA) Using Salt Formation with Organic and Alkali Metal Bases.

Science.gov (United States)

Pawar, Vijay; Naik, Prashant; Giridhar, Rajani; Yadav, Mange Ram

2015-01-01

In the present study, a series of organic and alkali metal salts of biphenylacetic acid (BPA) have been prepared and evaluated in vitro for percutaneous drug delivery. The physicochemical properties of BPA salts were determined using solubility measurements, DSC, and IR. The DSC thermogram and FTIR spectra confirmed the salt formation with organic and alkali metal bases. Among the series, salts with organic amines (ethanolamine, diethanolamine, triethanolamine, and diethylamine) had lowered melting points while the alkali metal salt (sodium) had a higher melting point than BPA. The in vitro study showed that salt formation improves the physicochemical properties of BPA, leading to improved permeability through the skin. Amongst all the prepared salts, ethanolamine salt (1b) showed 7.2- and 5.4-fold higher skin permeation than the parent drug at pH 7.4 and 5.0, respectively, using rat skin.

Enzymatic saccharification of dilute acid pretreated saline crops for fermentable sugar production

Energy Technology Data Exchange (ETDEWEB)

Zheng, Yi; Zhang, Ruihong [Biological and Agricultural Engineering Department, University of California, Davis One Shields Avenue, Davis, CA 95616 (United States); Pan, Zhongli [Biological and Agricultural Engineering Department, University of California, Davis One Shields Avenue, Davis, CA 95616 (United States); Processed Foods Research Unit, USDA-ARS-WRRC, 800 Buchanan Street, Albany, CA 94710 (United States); Wang, Donghai [Biological and Agricultural Engineering Department, Kansas State University, Manhattan, KS 66506 (United States)

2009-11-15

Four saline crops [athel (Tamarix aphylla L), eucalyptus (Eucalyptus camaldulensis), Jose Tall Wheatgrass (Agropyron elongatum), and Creeping Wild Ryegrass (Leymus triticoides)] that are used in farms for salt uptake from soil and drainage irrigation water have the potential for fuel ethanol production because they don't take a large number of arable lands. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions and the best saline crop for further enzymatic hydrolysis research. The optimum dilute acid pretreatment conditions included T = 165 C, t = 8 min, and sulfuric acid concentration 1.4% (w/w). Creeping Wild Ryegrass was decided to be the best saline crop. Solid loading, cellulase and {beta}-glucosidase concentrations had significant effects on the enzymatic hydrolysis of dilute acid pretreated Creeping Wild Ryegrass. Glucose concentration increased by 36 mg/mL and enzymatic digestibility decreased by 20% when the solid loading increased from 4 to 12%. With 8% solid loading, enzymatic digestibility increased by over 30% with the increase of cellulase concentration from 5 to 15 FPU/g-cellulose. Under given cellulase concentration of 15 FPU/g-cellulose, 60% increase of enzymatic digestibility of pretreated Creeping Wild Ryegrass was obtained with the increase of {beta}-glucosidase concentration up to 15 CBU/g-cellulose. With a high solid loading of 10%, fed-batch operation generated 12% and 18% higher enzymatic digestibility and glucose concentration, respectively, than batch process. (author)

ALKALI RESISTANT CATALYST

DEFF Research Database (Denmark)

2008-01-01

The present invention concerns the selective removal of nitrogen oxides (NOx) from gasses. In particular, the invention concerns a process, a catalyst and the use of a catalyst for the selective removal of nitrogen oxides in the presence of ammonia from gases containing a significant amount...... of alkali metal and/or alkali-earth compounds which process comprises using a catalyst combined of (i) a formed porous superacidic support, said superacidic support having an Hammett acidity stronger than Ho=-12, and (ii) a metal oxide catalytic component deposited on said superacidic support selected from...

Conversion of rice straw to sugars by dilute-acid hydrolysis

International Nuclear Information System (INIS)

Karimi, Keikhosro; Kheradmandinia, Shauker; Taherzadeh, Mohammad J.

2006-01-01

Hydrolysis of rice straw by dilute sulfuric acid at high temperature and pressure was investigated in one and two stages. The hydrolyses were carried out in a 10-l reactor, where the hydrolysis retention time (3-10 min), pressure (10-35 bar) and acid concentration (0-1%) were examined. Optimization of first stage hydrolysis is desirable to achieve the highest yield of the sugars from hemicellulose and also as a pretreatment for enzymatic hydrolysis. The results show the ability of first stage hydrolysis to depolymerize xylan to xylose with a maximum yield of 80.8% at hydrolysis pressure of 15 bar, 10 min retention time and 0.5% acid concentration. However, the yield of glucose from glucan was relatively low in first stage hydrolysis at a maximum of 25.8%. The solid residuals were subjected to further dilute-acid hydrolysis in this study. This second-stage hydrolysis without addition of the acid could not increase the yield of glucose from glucan beyond 26.6%. On the other hand, the best results of the hydrolysis were achieved, when 0.5% sulfuric acid was added prior to each stage in two-stage hydrolysis. The best results of the second stage of the hydrolysis were achieved at the hydrolysis pressure and the retention time of 30 bar and 3 min in the second stage hydrolysis, where a total of 78.9% of xylan and 46.6% of glucan were converted to xylose and glucose, respectively in the two stages. Formation of furfural and HMF were functions of the hydrolysis pressure, acid concentration, and retention time, whereas the concentration of acetic acid was almost constant at pressure of higher than 10 bar and a total retention time of 10 min

Kinetic study of dilute nitric acid treatment of corn stover at relatively high temperature

Energy Technology Data Exchange (ETDEWEB)

Zhang, R.; Lu, X.; Liu, Y.; Wang, X.; Zhang, S. [Tianjin University, School of Environmental Science and Technology, Tianjin (China)

2011-03-15

Corn stover was hydrolyzed using dilute nitric acid at 150 C. Several concentrations of HNO{sub 3} (0.2, 0.4 and 0.6 wt-%) and reaction times (0-60 min) were evaluated. The kinetic parameters of mathematical models for predicting the concentrations of xylose, glucose, arabinose, acetic acid, and furfural in the hydrolysates were determined. The hydrolysates obtained from corn stover can be used to produce methane by an anaerobic fermentation process. Thus, the hydrolysis process of corn stover using dilute nitric acid can be conceived as the first stage of an integrated strategy for corn stover utilization. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Characteristics of alkali activated material (geopolymer) in sulfuric acid solution

Science.gov (United States)

Simatupang, Partogi H.

2017-09-01

Alkali Activated Material (AAM) or Geopolymer is a solid material which made by mixing rich silica alumina material with alkaline activator. AAM is a well known candidate to replace cement based material. Many researches have claimed that AAM has better durability compared to cement based material in agressive environment. However, there was rare paper presented the direct comparison of material characteristics between Class F fly ash based AAM and Class C fly ash based AAM in such aggresive environment. Because of that, this paper present material characteristics of Class F fly ash based AAM and Class C fly ash based AAM if the materials were immersed in 10% sulfuric acid solution for 65 days. Material characteristics evaluated were (1) weight loss, (2) mineral of the material which evaluated by XRD (X-Ray Diffraction), (3) morphology and oxide compounds of material which evaluated by SEM/EDXA (Scanning Electron Microscopic/Energy Dispersive X-Ray Analyzer) and (4) compound bond which evaluated by FTIR (Fourier Transform Infra Red) Spectroscopy Testing. Alkali Activated Material used were Class F fly ash based AAM Mortar and Class C fly ash based AAM Mortar. The result is a quite difference of material characteristics between Class F fly ash based AAM and Class C fly ash based AAM.

Hydrolysis of dilute acid-pretreated cellulose under mild hydrothermal conditions.

Science.gov (United States)

Chimentão, R J; Lorente, E; Gispert-Guirado, F; Medina, F; López, F

2014-10-13

The hydrolysis of dilute acid-pretreated cellulose was investigated in a conventional oven and under microwave heating. Two acids--sulfuric and oxalic--were studied. For both hydrothermal conditions (oven and microwave) the resultant total organic carbon (TOC) values obtained by the hydrolysis of the cellulose pretreated with sulfuric acid were higher than those obtained by the hydrolysis of the cellulose pretreated with oxalic acid. However, the dicarboxylic acid exhibited higher hydrolytic efficiency towards glucose. The hydrolysis of cellulose was greatly promoted by microwave heating. The Rietveld method was applied to fit the X-ray patterns of the resultant cellulose after hydrolysis. Oxalic acid preferentially removed the amorphous region of the cellulose and left the crystalline region untouched. On the other hand, sulfuric acid treatment decreased the ordering of the cellulose by partially disrupting its crystalline structure. Copyright © 2014 Elsevier Ltd. All rights reserved.

The alkali halide disk technique in infra-red spectrometry : Anomalous behaviour of some samples dispersed in alkali halide disks

NARCIS (Netherlands)

Tolk, A.

1961-01-01

Some difficulties encountered in the application of the alkali halide disk technique in infra-red spectrometry are discussed. Complications due to interaction of the sample with the alkali halide have been studied experimentally. It was found that the anomalous behaviour of benzoic acid, succinic

Nucleic acid-binding glycoproteins which solubilize nucleic acids in dilute acid: re-examination of the Ustilago maydis glycoproteins

Energy Technology Data Exchange (ETDEWEB)

Unrau, P.; Champ, D.R.; Young, J.L.; Grant, C.E.

1980-01-01

Holloman reported the isolation from Ustilago maydis of a glycoprotein which prevented the precipitation of nucleic acids in cold 5% trichloroacetic acid. Two glycoprotein fractions from U. maydis with this nucleic acid-solubilizing activity were isolated in our laboratory using improved purification procedures. The activity was not due to nuclease contamination. The glycoproteins are distinguished by: their ability to bind to concanavalin A-Sepharose; their differential binding to double- and single-stranded deoxyribonucleic acid, and to ribonucleic acid; their molecular weights (46,000 and 69,000); and the relative amounts present in growing versus nongrowing cells. Both fractions required sulfhydryl-reducing conditions for optimal yields, specific activity, and stability. Nucleic acid binding was cooperative, the minimum number of glycoproteins required to make a native T7 DNA molecule soluble in dilute acid being estimated at 2 and 15, respectively.

The Adsorption Study of Aflatoxin B1 by Nanocellulose Conjugated with Aptamer in acidic, alkali, and Neutral Conditions

Directory of Open Access Journals (Sweden)

T Mirdehghan

2016-03-01

Full Text Available Introduction: Aflatoxin leads to liver cancer, its removal in the foodstuff is very important. The aim of this study is to investigate the adsorption of aflatoxin B1 by nanocellulose conjugated with aptamer in acidic, alkali, and neutral conditions. Methods: First, nanocellulose was synthesized by acid hydrolysis and then conjugated with aptamer by cross-linker. Then, serial concentrations of conjugated nanocellulose (0.6, 1.25, 2.5, 5, and 10 mg/mL were separately mixed with aflatoxin solution (1000µg/mL, and incubated at  37 °C for 0.5 h at pH of 1, 7, and 13. Then, the percentage of aflatoxin adsorption was measured at 340 nm.   Results: The decrease of pH led to increase of adsorption up to 40%. Statistically, there was significant difference between the quantity of adsorption at acidic condition and the quantity of adsorption at alkali and neutral conditions (P<0.05. Conclusion: Aflatoxin could be adsorbed by conjugated nanocellulose, and this power of adsorption is increased at acidic condition.

Dilute-acid pretreatment of barley straw for biological hydrogen production using Caldicellulosiruptor saccharolyticus

NARCIS (Netherlands)

Panagiotopoulos, I.A.; Bakker, R.R.C.; Vrije, de G.J.; Claassen, P.A.M.; Koukios, E.G.

2012-01-01

The main objective of this study was to use the fermentability test to investigate the feasibility of applying various dilute acids in the pretreatment of barley straw for biological hydrogen production. At a fixed acid loading of 1% (w/w dry matter) 28-32% of barley straw was converted to soluble

Bioelectrochemical recovery of waste-derived volatile fatty acids and production of hydrogen and alkali

DEFF Research Database (Denmark)

Zhang, Yifeng; Angelidaki, Irini

2015-01-01

Volatile fatty acids (VFA) are organic compounds of great importance for various industries and environmental processes. Fermentation and anaerobic digestion of organic wastes are promising alternative technologies for VFA production. However, one of the major challenges is development...... of sustainable downstream technologies for VFA recovery. In this study, an innovative microbial bipolar electrodialysis cell (MBEDC) was developed to meet the challenge of waste-derived VFA recovery, produce hydrogen and alkali, and potentially treat wastewater. The MBEDC was operated in fed-batch mode....... At an applied voltage of 1.2 V, a VFA recovery efficiency of 98.3%, H2 of 18.4 mL and alkali production presented as pH of 12.64 were obtained using synthetic fermentation broth. The applied voltage, initial VFA concentrations and composition were affecting the VFA recovery. The energy balance revealed that net...

A dilute chemical decontaminant formulation containing gallic acid as a reductant

International Nuclear Information System (INIS)

Kishore, K.; Rajesh, P.; Kumbhar, A.G.

2001-01-01

Gallic acid (GA) was tried as a reductant in place of ascorbic acid in dilute chemical decontaminant (DCD) formulations. Dissolution of magnetite in GA based DCD formulations was studied at 50 C as well as 80 C. It was found to be a good substitute for ascorbic acid in EDTA/ascorbic acid/citric acid, i.e., EAC formulation. The efficiency of EDTA/GA/CA formulation was as good as that of EAC formulation. 2.8 was found to be the optimum pH for this formulation and dissolution decreased at lower as well as higher pHs. The ion exchange behaviour of GA is also appropriate for using it in a regenerating type of formulation. Being an aromatic compound, Gallic acid has inherent stability against radiation degradation. (orig.)

Determination of humic acid in alkali leaching solution of uranium by spectophotrometry-COD method

International Nuclear Information System (INIS)

Feng Yu; An Wei; Chen Shusen

2014-01-01

It is one of the main causes of extraction emulsification or resin toxicosis during alkali leaching process in uranium metallurgy which organic matters including humic acid exist in lixiviums. In order to study the effect of humic acid in uranium metallurgy, a method for determination of content of humic acid in aqueous solution need to be established. Spectrophotometry is a simple and convenient method in humic acid analysis. However, accuracy of spectrophotometry can be reduced greatly because of interference of uranium and other elements in the humic acid solutions. Although chemical oxygen demand (COD) method is a common analysis way of organic matters in aqueous solutions, the concentration of humic acid cannot be directly measured. In this paper, COD method is related with spectrophotometry to avoid the interference of uranium and ensure the accurate analysis of humic acid. The results showed that the detection limit of the method was 1.78 mg/L and the recovery rate was 101.2%. (authors)

The separation and determination of fatty acids by isotopic dilution and radiogas-liquid chromatography

International Nuclear Information System (INIS)

Beardsley, D.A.

1981-01-01

A number of static phases have been evaluated for the GLC separation of fatty acids. Of those investigated, only AT 1200 was capable of resolving the isomeric forms of the acids. A radiogas-liquid chromatographic method incorporating isotopic dilution analysis has been developed for the determination of n-butyric acid. The proposed method has been applied to the determination of the acid in hydrolysed butter fat and milk chocolate extracts. (author)

Reaction of alkali nitrates with PuO2

International Nuclear Information System (INIS)

Yamashita, T.; Ohuchi, K.; Takahashi, K.; Fujino, T.

1990-01-01

Improvement of solubility of plutonium dioxide (PuO 2 ) in acid solution is important to establish the nuclear fuel reprocessing technique for uranium-plutonium mixed oxide fuels. If insoluble PuO 2 can be converted into any soluble plutonium compounds, problems arising from the fuel dissolution process will be reduced to a great extent. Alkali metal plutonates and alkaline-earth plutonates are known to have enhanced solubility in mineral acids. However, the reaction conditions to form such plutonates and characterization thereof are not well elucidated. Then the reactivity and reaction conditions to form lithium and sodium plutonates from their nitrates and PuO 2 were studied at temperatures between 500 and 900 degree C and alkali metal to plutonium atom ratios between 0.5 and 6 by means of thermogravimetry as well as X-ray diffraction technique. The reaction behavior of alkali plutonates will be discussed in comparison with corresponding alkali uranates

Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production

Directory of Open Access Journals (Sweden)

Murthy Ganti S

2011-09-01

Full Text Available Abstract Background While advantages of biofuel have been widely reported, studies also highlight the challenges in large scale production of biofuel. Cost of ethanol and process energy use in cellulosic ethanol plants are dependent on technologies used for conversion of feedstock. Process modeling can aid in identifying techno-economic bottlenecks in a production process. A comprehensive techno-economic analysis was performed for conversion of cellulosic feedstock to ethanol using some of the common pretreatment technologies: dilute acid, dilute alkali, hot water and steam explosion. Detailed process models incorporating feedstock handling, pretreatment, simultaneous saccharification and co-fermentation, ethanol recovery and downstream processing were developed using SuperPro Designer. Tall Fescue (Festuca arundinacea Schreb was used as a model feedstock. Results Projected ethanol yields were 252.62, 255.80, 255.27 and 230.23 L/dry metric ton biomass for conversion process using dilute acid, dilute alkali, hot water and steam explosion pretreatment technologies respectively. Price of feedstock and cellulose enzymes were assumed as $50/metric ton and 0.517/kg broth (10% protein in broth, 600 FPU/g protein respectively. Capital cost of ethanol plants processing 250,000 metric tons of feedstock/year was $1.92, $1.73, $1.72 and $1.70/L ethanol for process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Ethanol production cost of $0.83, $0.88, $0.81 and $0.85/L ethanol was estimated for production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment respectively. Water use in the production process using dilute acid, dilute alkali, hot water and steam explosion pretreatment was estimated 5.96, 6.07, 5.84 and 4.36 kg/L ethanol respectively. Conclusions Ethanol price and energy use were highly dependent on process conditions used in the ethanol production plant. Potential for

[Diversity of uncultured actinomycetes in saline-alkali soil from Jiuquan area of Hexi Corridor].

Science.gov (United States)

Li, Hai-yun; Niu, Shi-quan; Kong, Wei-bao; Yan, Wei-ru; Geng, Hui; Han, Cai-hong; Da, Wen-yan; Zhang, Ai-mei; Zhu, Xue-tai

2015-09-01

In order to more accurately understand community structure and diversity of actinomycetes in saline-alkali soil from Jiuquan area of Hexi Corridor, the community structure and diversity from three kinds of soil samples (primary, secondary saline alkali soil and farmland soil) were analyzed using uncultured methods. The results showed that the 16S rDNA clone library of actinomycetales from the primary saline-alkali soil belonged to 19 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; the 16S r DNA clone library of actinomycetales from the secondary saline-alkali soil belonged to 14 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; the 16S rDNA clone library of farmland soil belonged to 7 OTUs, Micrococcineae, Propionibacterineae, Corynebacterineae, Frankineae, Pseudonocardineae and unknown groups of Actinomycetales; Micrococcineae was the common population in the three soils, and also was the dominant population in primary saline alkali soil and farmland soil. The diversity index and rarefaction curves analysis showed that actinomycetes species richness was in order of primary saline-alkali soil > secondary saline-alkali soil > farmland soil. The dilution curves of primary saline-alkali soil and secondary saline-alkali soil were not leveled off, which indicated the actinomycetes diversity in saline-alkali soil was more enriched than the actual. The rich and diverse actinomycetes resources in saline-alkali soil from Jiuquan area of Hexi Corridor provide important data on the actinomycetes ecology distribution research, exploitation and utilization in saline-alkali soil.

Milk Alkali and Hydrochlorothiazide: A Case Report

Directory of Open Access Journals (Sweden)

Babar Parvez

2011-01-01

Full Text Available Hypercalcemia is a relatively common clinical problem in both outpatient and inpatient settings. Primary pathophysiology is the entry of calcium that exceeds its excretion into urine or deposition in bone into circulation. Among a wide array of causes of hypercalcemia, hyperparathyroidism and malignancy are the most common, accounting for greater than 90 percent of cases. Concordantly, there has been a resurgence of milk-alkali syndrome associated with the ingestion of large amounts of calcium and absorbable alkali, making it the third leading cause of hypercalcemia (Beall and Scofield, 1995 and Picolos et al., 2005. This paper centers on a case of over-the-counter calcium and alkali ingestion for acid reflux leading to milk alkali with concordant use of thiazide diuretic for hypertension.

Repletion of branched chain amino acids reverses mTORC1 signaling but not improved metabolism during dietary protein dilution

DEFF Research Database (Denmark)

Maida, Adriano; Chan, Jessica S K; Sjøberg, Kim Anker

2017-01-01

OBJECTIVE: Dietary protein dilution (PD) has been associated with metabolic advantages such as improved glucose homeostasis and increased energy expenditure. This phenotype involves liver-induced release of FGF21 in response to amino acid insufficiency; however, it has remained unclear whether...... dietary dilution of specific amino acids (AAs) is also required. Circulating branched chain amino acids (BCAAs) are sensitive to protein intake, elevated in the serum of obese humans and mice and thought to promote insulin resistance. We tested whether replenishment of dietary BCAAs to an AA-diluted (AAD......) diet is sufficient to reverse the glucoregulatory benefits of dietary PD. METHODS: We conducted AA profiling of serum from healthy humans and lean and high fat-fed or New Zealand obese (NZO) mice following dietary PD. We fed wildtype and NZO mice one of three amino acid defined diets: control, total...

Exploring orange peel treatment with deep eutectic solvents and diluted organic acids

NARCIS (Netherlands)

van den Bruinhorst, A.; Kouris, P.; Timmer, J.M.K.; de Croon, M.H.J.M.; Kroon, M.C.

2016-01-01

The disintegration of orange peel waste in deep eutectic solvents and diluted organic acids is presented in this work. The albedo and flavedo layers of the peel were studied separately, showing faster disintegration of the latter. Addition of water to the deep eutectic solvents lowered the amount of

Bioethanol production from microwave-assisted acid or alkali-pretreated agricultural residues of cassava using separate hydrolysis and fermentation (SHF).

Science.gov (United States)

Pooja, N S; Sajeev, M S; Jeeva, M L; Padmaja, G

2018-01-01

The effect of microwave (MW)-assisted acid or alkali pretreatment (300 W, 7 min) followed by saccharification with a triple enzyme cocktail (Cellic, Optimash BG and Stargen) with or without detoxification mix on ethanol production from three cassava residues (stems, leaves and peels) by Saccharomyces cerevisiae was investigated. Significantly higher fermentable sugar yields (54.58, 47.39 and 64.06 g/L from stems, leaves and peels, respectively) were obtained after 120 h saccharification from MW-assisted alkali-pretreated systems supplemented (D+) with detoxification chemicals (Tween 20 + polyethylene glycol 4000 + sodium borohydride) compared to the non-supplemented (D0) or MW-assisted acid-pretreated systems. The percentage utilization of reducing sugars during fermentation (48 h) was also the highest (91.02, 87.16 and 89.71%, respectively, for stems, leaves and peels) for the MW-assisted alkali-pretreated (D+) systems. HPLC sugar profile indicated that glucose was the predominant monosaccharide in the hydrolysates from this system. Highest ethanol yields ( Y E , g/g), fermentation efficiency (%) and volumetric ethanol productivity (g/L/h) of 0.401, 78.49 and 0.449 (stems), 0.397, 77.71 and 0.341 (leaves) and 0.433, 84.65 and 0.518 (peels) were also obtained for this system. The highest ethanol yields (ml/kg dry biomass) of ca. 263, 200 and 303, respectively, for stems, leaves and peels from the MW-assisted alkali pretreatment (D+) indicated that this was the most effective pretreatment for cassava residues.

Citrate, malate and alkali content in commonly consumed diet sodas: implications for nephrolithiasis treatment.

Science.gov (United States)

Eisner, Brian H; Asplin, John R; Goldfarb, David S; Ahmad, Ardalanejaz; Stoller, Marshall L

2010-06-01

Citrate is a known inhibitor of calcium stone formation. Dietary citrate and alkali intake may have an effect on citraturia. Increasing alkali intake also increases urine pH, which can help prevent uric acid stones. We determined citrate, malate and total alkali concentrations in commonly consumed diet sodas to help direct dietary recommendations in patients with hypocitraturic calcium or uric acid nephrolithiasis. Citrate and malate were measured in a lemonade beverage commonly used to treat hypocitraturic calcium nephrolithiasis and in 15 diet sodas. Anions were measured by ion chromatography. The pH of each beverage was measured to allow calculation of the unprotonated anion concentration using the known pK of citric and malic acid. Total alkali equivalents were calculated for each beverage. Statistical analysis was done using Pearson's correlation coefficient. Several sodas contained an amount of citrate equal to or greater than that of alkali and total alkali as a lemonade beverage commonly used to treat hypocitraturic calcium nephrolithiasis (6.30 mEq/l citrate as alkali and 6.30 as total alkali). These sodas were Diet Sunkist Orange, Diet 7Up, Sprite Zero, Diet Canada Dry Ginger Ale, Sierra Mist Free, Diet Orange Crush, Fresca and Diet Mountain Dew. Colas, including Caffeine Free Diet Coke, Coke Zero, Caffeine Free Diet Pepsi and Diet Coke with Lime, had the lowest total alkali (less than 1.0 mEq/l). There was no significant correlation between beverage pH and total alkali content. Several commonly consumed diet sodas contain moderate amounts of citrate as alkali and total alkali. This information is helpful for dietary recommendations in patients with calcium nephrolithiasis, specifically those with hypocitraturia. It may also be useful in patients with low urine pH and uric acid stones. Beverage malate content is also important since malate ingestion increases the total alkali delivered, which in turn augments citraturia and increases urine pH. Copyright

The influence of alkali fatty acids on the properties and the stability of parenteral O/W emulsions modified with solutol HS 15.

Science.gov (United States)

Buszello, K; Harnisch, S; Müller, R H; Müller, B W

2000-03-01

Arachis oil based parenteral O/W emulsions were prepared using soya bean phosphatidylcholine (SPC) and different combinations of co-emulsifiers containing polyethylene glycol fatty acid esters (Solutol HS 15) and alkali fatty acids (sodium laurate, sodium stearate). The parameters measured were droplet size (both by photon correlation spectroscopy and laser diffractometry), pH and zeta potential. All emulsions were subjected to autoclaving. The addition of polyethylene glycol 12-hydroxy stearate (Solutol HS 15) led to a significant decrease of mean oil droplet size. For long-term stability the amount added turned out to be the most important factor. With increased amounts of Solutol HS 15 the packing density of the emulsifier layer and the zeta potential decreased leading to instability. The optimum load of Solutol HS 15 was found to be 15 micromol/ml. Alkali fatty acids markedly improved the physical stability of the emulsions. Improved stability properties conferred to emulsions by alkali fatty acids could be attributed to the zeta potential increase even in the presence of Solutol HS 15. Consequently a mixed emulsifier film was established in which the ionized fatty acids determined the interface charge. In addition to this a strengthening of the molecular interactions occurring between phospholipid and Solutol HS 15 emulsifier in the presence of ionized fatty acids at the O/W interface can be assumed (L. Rydhag, The importance of the phase behaviour of phospholipids for emulsion stability, Fette Seifen Anstrichm. 81 (1979) 168-173). Different co-emulsifier mixtures were shown to have a pronounced impact on the plasma protein adsorption onto emulsion droplets.

Determination of the common and rare alkalies in mineral analysis

Science.gov (United States)

Wells, R.C.; Stevens, R.E.

1934-01-01

Methods are described which afford a determination of each member of the alkali group and are successful in dealing with the quantities of the rare alkalies found in rocks and minerals. The procedures are relatively rapid and based chiefly on the use of chloroplatinic acid, absolute alcohol and ether, and ammonium sulfate. The percentages of all the alkalies found in a number of minerals are given.

Saturated vapor pressure over molten mixtures of GaCl3 and alkali metal chlorides

International Nuclear Information System (INIS)

Salyulev, A.B.; Smolenskij, V.V.; Moskalenko, N.I.

2004-01-01

Volatilities of GaCl 3 and alkali metal chlorides over diluted (up to 3 mol %) solutions of GaCl 3 in LiCl, NaCl, KCl, RbCl, and CsCl were measured at 1100 K by dynamic and indirect static methods. Chemical composition of saturated vapor over the mixed melts was determined. Partial pressures of the components were calculated. Their values depend essentially on specific alkali metal cation and on concentration of GaCl 3 ; their variation permits altering parameters of GaCl 3 distillation from the salt melt in a wide range [ru

Bioconversion of dilute-acid pretreated sorghum bagasse to ethanol by Neurospora crassa

Energy Technology Data Exchange (ETDEWEB)

Dogaris, Ioannis; Gkounta, Olga; Mamma, Diomi; Kekos, Dimitris [National Technical Univ. of Athens, Zografou (Greece). Biotechnology Lab.

2012-07-15

Bioethanol production from sweet sorghum bagasse (SB), the lignocellulosic solid residue obtained after extraction of sugars from sorghum stalks, can further improve the energy yield of the crop. The aim of the present work was to evaluate a cost-efficient bioconversion of SB to ethanol at high solids loadings (16 % at pretreatment and 8 % at fermentation), low cellulase activities (1-7 FPU/g SB) and co-fermentation of hexoses and pentoses. The fungus Neurospora crassa DSM 1129 was used, which exhibits both depolymerase and co-fermentative ability, as well as mixed cultures with Saccharomyces cerevisiae 2541. A dilute-acid pretreatment (sulfuric acid 2 g/100 g SB; 210 C; 10 min) was implemented, with high hemicellulose decomposition and low inhibitor formation. The bioconversion efficiency of N. crassa was superior to S. cerevisiae, while their mixed cultures had negative effect on ethanol production. Supplementing the in situ produced N. crassa cellulolytic system (1.0 FPU/g SB) with commercial cellulase and {beta}-glucosidase mixture at low activity (6.0 FPU/g SB) increased ethanol production to 27.6 g/l or 84.7 % of theoretical yield (based on SB cellulose and hemicellulose sugar content). The combined dilute-acid pretreatment and bioconversion led to maximum cellulose and hemicellulose hydrolysis 73.3 % and 89.6 %, respectively. (orig.)

Hydrogen isotope exchange of organic compounds in dilute acid at elevated temperatures

International Nuclear Information System (INIS)

Werstiuk, N.H.

1987-01-01

Introduction of one or more deuterium (or tritium) atoms into organic molecules can be accomplished in many ways depending on the nature of the substrate and the extent and sterochemistry of deuteriation or tritiation required. Some of the common methods include acid- and base-catalyzed exchange of carbonyl compounds, metal hydride reductions, dissolving metal reductions, catalytic reduction of double bonds, chromatographic exchange, homogeneous and heterogeneous metal-catalyzed exchange, base-catalyzed exchange of carbon acids other than carbonyl compounds and acid-catalyzed exchange via electrophilic substitution. Only the latter three methods have been used for perdeuteriation of organic compounds. A very useful compendium of labeling methods with examples has been available to chemists for some time. Although metal-catalyzed exchange has been used extensively, the method suffers from some deficiencies: irreproducibility of catalyst surfaces, catalyst poisoning, side reactions such as coupling and hydrogenolysis of labile groups and low deuterium incorporation. Usually a number of cycles are required with fresh catalyst and fresh deuterium source to achieve substantial isotope incorporation. Acid-catalyzed exchange of aromatics and alkenes, strongly acidic media such as liquid DBr, concentrated DBr, acetic acid/stannic chloride, concentrated D 3 PO 4 , concentrated DC1, D 3 PO 4 /BF 3 SO 2 , 50-80% D 2 SO 4 and DFSO 4 /SbF 5 at moderate temperatures (<100 degrees) have been used to effect exchange. The methods are not particularly suitable for large scale deuteriations because of the cost and the fact that the recovery and upgrading of the diluted deuterium pool is difficult. This paper describes the hydrogen isotope exchange of a variety of organic compounds in dilute aqueous acid (0.1-0.5 M) at elevated temperatures (150-300 degrees)

UTILIZATION OF OIL PALM EMPTY FRUIT BUNCH (OPEFB FOR BIOETHANOL PRODUCTION THROUGH ALKALI AND DILUTE ACID PRETREATMENT AND SIMULTANEOUS SACCHARIFICATION AND FERMENTATION

Directory of Open Access Journals (Sweden)

Yanni Sudiyani

2010-07-01

Full Text Available Lignocellulosic biomass is a potential alternative source of bioethanol for energy. The lignocellulosics are abundantly available in Indonesia. Most of them are wastes of agriculture, plantation and forestry. Among those wastes, oil palm empty fruit bunch (OP EFB is one of a potential lignocellulosics to be converted to bioethanol. This EFB, which is wastes in oil palm factories, is quite abundant (around 25 million tons/year and also has high content of cellulose (41-47%. The conversion of OPEFB to ethanol basically consists of three steps which are pretreatment, hydrolysis of cellulose and hemicellulose to simple sugars (hexoses and pentoses, and fermentation of simple sugars to ethanol. Acid and alkali pretreatments are considered the simplest methods and are potentially could be applied in the next couple of years. However, there are still some problems that have to be overcome to make the methods economically feasible. The high price of cellulose enzyme that is needed in the hydrolysis step is one of factors that cause the cost of EFB conversion is still high. Thus, the search of potential local microbes that could produce cellulase is crucial. Besides that, it is also important to explore fermenting microbes that could ferment six carbon sugars from cellulose as well as five carbon sugars from hemicellulose, so that the conversion of lignocellulosics, particularly EFB, would be more efficient. Keywords: OPEFB, lignocellulosics, pretreatment, fermentation, ethanol

Xylanase supplementation on enzymatic saccharification of dilute acid pretreated poplars at different severities

Science.gov (United States)

Chao Zhang; Xinshu Zhuang; Zhao Jiang Wang; Fred Matt; Franz St. John; J.Y. Zhu

2013-01-01

Three pairs of solid substrates from dilute acid pretreatment of two poplar wood samples were enzymatically hydrolyzed by cellulase preparations supplemented with xylanase. Supplementation of xylanase improved cellulose saccharification perhaps due to improved cellulose accessibility by xylan hydrolysis. Total xylan removal directly affected enzymatic cellulose...

Ethanol production from industrial hemp: effect of combined dilute acid/steam pretreatment and economic aspects

DEFF Research Database (Denmark)

Gunnarsson, Ingólfur Bragi; Svensson, Sven-Erik; Prade, Thomas

2014-01-01

In the present study, combined steam (140-180 °C) and dilute-acid pre-hydrolysis (0.0-2.0%) were applied to industrial hemp (Cannabis sativa L.), as pretreatment for lignocellulosic bioethanol production. The influence of the pretreatment conditions and cultivation type on the hydrolysis and etha......In the present study, combined steam (140-180 °C) and dilute-acid pre-hydrolysis (0.0-2.0%) were applied to industrial hemp (Cannabis sativa L.), as pretreatment for lignocellulosic bioethanol production. The influence of the pretreatment conditions and cultivation type on the hydrolysis...... pretreated at the optimal conditions showed positive economic results. The type of hemp cultivation (organic or conventional) did not influence significantly the effectiveness of the pretreatment and subsequent enzymatic hydrolysis and ethanol fermentation....

High-Yield Production of Levulinic Acid from Pretreated Cow Dung in Dilute Acid Aqueous Solution

Directory of Open Access Journals (Sweden)

Jialei Su

2017-02-01

Full Text Available Agricultural waste cow dung was used as feedstock for the production of a high value–added chemical levulinic acid (LA in dilute acid aqueous solutions. A high LA yield of 338.9 g/kg was obtained from the pretreated cow dung, which was much higher than that obtained from the crude cow dung (135 g/kg, mainly attributed to the breakage of the lignin fraction in the lignocellulose structure of the cow dung by potassium hydroxide (KOH pretreatment, and thus enhanced the accessibility of cow dung to the acid sites in the catalytic reaction. Meanwhile, another value-added chemical formic acid could be obtained with a yield of ca. 160 g/kg in the process, implying a total production of ca. 500 g/kg yield for LA and formic acid from the pretreated cow dung with the proposed process. The developed process was shown to be tolerant to high initial substrate loading with a satisfied LA yield. This work provides a promising strategy for the value-increment utilization of liglocellulosic agricultural residues.

Effects of SPORL and dilute acid pretreatment on substrate morphology, cell physical and chemical wall structures, and subsequent enzymatic hydrolysis of lodgepole pine.

Science.gov (United States)

Li, Xinping; Luo, Xiaolin; Li, Kecheng; Zhu, J Y; Fougere, J Dennis; Clarke, Kimberley

2012-11-01

The effects of pretreatment by dilute acid and sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) on substrate morphology, cell wall physical and chemical structures, along with the subsequent enzymatic hydrolysis of lodgepole pine substrate were investigated. FE-SEM and TEM images of substrate structural morphological changes showed that SPORL pretreatment resulted in fiber separation, where SPORL high pH (4.2) pretreatment exhibited better fiber separation than SPORL low pH (1.9) pretreatment. Dilute acid pretreatment produced very poor fiber separation, consisting mostly of fiber bundles. The removal of almost all hemicelluloses in the dilute acid pretreated substrate did not overcome recalcitrance to achieve a high cellulose conversion when lignin removal was limited. SPORL high pH pretreatment removed more lignin but less hemicellulose, while SPORL low pH pretreatment removed about the same amount of lignin and hemicelluloses in lodgepole pine substrates when compared with dilute acid pretreatment. Substrates pretreated with either SPORL process had a much higher cellulose conversion than those produced with dilute acid pretreatment. Lignin removal in addition to removal of hemicellulose in SPORL pretreatment plays an important role in improving the cellulose hydrolysis of the substrate.

Optimisation of dilute acid pre-treatment of artisan rice hulls for ethanol production

International Nuclear Information System (INIS)

Lopez, Yoney; Martin, Carlos; Gullon, Beatriz; Parajo, Juan Carlos

2011-01-01

Rice hulls are potential low-cost feedstocks for fuel ethanol production in many countries. In this work, the dilute-acid pre-treatment of artisan rice hulls was investigated using a central composite rotatable experimental design. The experimental variables were temperature (140-210 C), biomass load (5-20%) and sulphuric acid concentration (0.5-1.5 g per 100 g of reaction mixture). A total of 16 experimental runs, including a 23-plan, two replicates at the central point and six star points, were carried out. Low temperatures were found to be favourable for the hydrolysis of xylan and of the easily hydrolyzable glucan fraction. High glucose formation (up to 15.3 g/100 g), attributable to starch hydrolysis, was detected in the hydrolysates obtained under the least severe pre-treatment conditions. Using the experimental results, several models for predicting the effect of the operational conditions on the yield of pretreated solids, xylan and glucan conversion upon pre-treatment, and on enzymatic convertibility of cellulose were developed. Optimum results were predicted for the conversion of easily-hydrolyzable glucan in the material pretreated at 140.7 C, and for the enzymatic saccharification of cellulose in the material pretreated at 169 C. These results suggested the use of two-step acid hydrolysis as future pre-treatment strategy for artisan rice hulls. Key words: Dilute acid hydrolysis, enzymatic hydrolysis, pre-treatment, rice hulls. (author)

Bioconversion of dilute-acid pretreated sorghum bagasse to ethanol by Neurospora crassa.

Science.gov (United States)

Dogaris, Ioannis; Gkounta, Olga; Mamma, Diomi; Kekos, Dimitris

2012-07-01

Bioethanol production from sweet sorghum bagasse (SB), the lignocellulosic solid residue obtained after extraction of sugars from sorghum stalks, can further improve the energy yield of the crop. The aim of the present work was to evaluate a cost-efficient bioconversion of SB to ethanol at high solids loadings (16 % at pretreatment and 8 % at fermentation), low cellulase activities (1-7 FPU/g SB) and co-fermentation of hexoses and pentoses. The fungus Neurospora crassa DSM 1129 was used, which exhibits both depolymerase and co-fermentative ability, as well as mixed cultures with Saccharomyces cerevisiae 2541. A dilute-acid pretreatment (sulfuric acid 2 g/100 g SB; 210 °C; 10 min) was implemented, with high hemicellulose decomposition and low inhibitor formation. The bioconversion efficiency of N. crassa was superior to S. cerevisiae, while their mixed cultures had negative effect on ethanol production. Supplementing the in situ produced N. crassa cellulolytic system (1.0 FPU/g SB) with commercial cellulase and β-glucosidase mixture at low activity (6.0 FPU/g SB) increased ethanol production to 27.6 g/l or 84.7 % of theoretical yield (based on SB cellulose and hemicellulose sugar content). The combined dilute-acid pretreatment and bioconversion led to maximum cellulose and hemicellulose hydrolysis 73.3 % and 89.6 %, respectively.

Nicotinic acid as a nontoxic corrosion inhibitor for hot dipped Zn and Zn-Al alloy coatings on steels in diluted hydrochloric acid

Energy Technology Data Exchange (ETDEWEB)

Ju Hong [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China); Graduate School, Chinese Academy of Sciences, Beijing 100039 (China); Li Yan [Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071 (China)], E-mail: yanlee@ms.qdio.ac.cn

2007-11-15

The inhibition effect of nicotinic acid for corrosion of hot dipped Zn and Zn-Al alloy coatings in diluted hydrochloric acid was investigated using quantum chemistry analysis, weight loss test, electrochemical measurement, and scanning electronic microscope (SEM) analysis. Quantum chemistry calculation results showed that nicotinic acid possessed planar structure with a number of active centers, and the populations of the Mulliken charge, the highest occupied molecular orbital (HOMO), and the lowest unoccupied molecular orbital (LUMO) were found mainly focused around oxygen and nitrogen atoms, and the cyclic of the benzene as well. The results of weight loss test and electrochemical measurement indicated that inhibition efficiency (IE%) increased with inhibitor concentration, and the highest inhibition efficiency was up to 96.7%. The corrosion inhibition of these coatings was discussed in terms of blocking the electrode reaction by adsorption of the molecules at the active centers on the electrode surface. It was found that the adsorption of nicotinic acid on coating surface followed Langmuir adsorption isotherm with single molecular layer, and nicotinic acid adsorbed on the coating surface probably by chemisorption. Nicotinic acid, therefore, can act as a good nontoxic corrosion inhibitor for hot dipped Zn and Zn-Al alloy coatings in diluted hydrochloric acid solution.

Autoclave-hardening slag-alkali binder with high water content

International Nuclear Information System (INIS)

Korenevskij, V.V.; Kozyrin, N.A.; Melikhova, N.I.; Narkevich, N.K.; Ryabov, G.G.

1987-01-01

The results of investigations into properties of slag-alkali binder, that may be used for concretes of reactor radiation and thermal shieldings, are presented. These concretes have increased chemical stability and mechanical strength, high content of chemically bound water (approximately 14%), that is not lost under heating up to 550 deg C. Dumping and granulated slags of blast-furnace process, sodium-bicarbonate-alkali fusion cake formed at burning of adipic acid residues, technical sodium hydroxide and sodium liquid glass are used as raw material for slag-alkali binder

Protection of protein from ruminal degradation by alkali-induced oxidation of chlorogenic acid in sunflower meal.

Science.gov (United States)

Bongartz, V; Böttger, C; Wilhelmy, N; Schulze-Kaysers, N; Südekum, K-H; Schieber, A

2018-02-01

Lactating ruminants require an adequate supply of absorbable amino acids for the synthesis of milk protein from two sources, that is crude protein (CP) synthesized microbially in the rumen and ruminally undegraded CP (RUP) from feed which can both be digested in the small intestine. Several chemical and physical methods have been identified as being effective in increasing the proportion of RUP of total CP of a feedstuff, yet there is a continuing need for developing and establishing methods which protect feed protein from ruminal degradation with acceptable expenditure of labour and other costs. The objective of this study was to identify and quantify effects of and interactions between chlorogenic acid and protein in solvent-extracted sunflower meal (SFM) as induced by alkali treatment. Response surface methodology was employed to investigate the influence of pH, reaction time and drying temperature on the resulting SFM and, subsequently, its protein value for ruminants estimated from laboratory values. For this purpose, alkali-treated SFM was subjected to a fractionation of feed CP according to the Cornell net carbohydrate and protein system as a basis for estimating RUP at different assumed ruminal passage rates (K p ). To estimate the intestinal digestibility of the treated SFM and its RUP, a three-step enzymatic in vitro procedure was applied. Alkaline treatment of SFM increased RUP values with factors ranging from approximately 3 (K p =.08/hr) to 12 (K p =.02/hr). Furthermore, the intestinal digestibility of the alkali-treated SFM was enhanced by approximately 10% compared to untreated SFM. Increasing pH and reaction time led to both increasing RUP values and intestinal digestibility. In conclusion, a targeted alkaline treatment of naturally occurring compounds in feedstuffs might be a promising approach to provide high-RUP feeds for ruminants which, at the same time, have improved intestinal digestibility values. © 2017 Blackwell Verlag GmbH.

The pitting resistance of AISI 316 stainless steel passivated in diluted nitric acid

International Nuclear Information System (INIS)

Barbosa, M.A.

1983-01-01

The pitting resistance of AISI 316 stainless steel after passivation in diluted nitric acid was studied in comparison with that of non-passivated specimens. The passivation treatment increased the pitting potential but decreased the resistance to crevice corrosion under open circuit conditions in aerated sea water. Immersion in the nitric acid solution was found to remove the sulphide inclusions from the metal surface, thus eliminating the most susceptible sites for attack. In the absence of sulphide particles pitting nucleated at aluminium-rich oxides. (author)

Effect of alkali treatment on the mechanical properties of Poly (lactic acid / Guineacorn husk particulate bio-composites

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Umar SHEHU

2016-12-01

Full Text Available The paper focuses on the influence of alkali treatment on the mechanical properties of biocomposites made from poly(lactic acid (PLA and guineacorn husks particulates (GHP with respect to that of the untreated (untrd biocomposites. The composites were prepared using a single screw extruder and an injection moulding machine with particulate compositions varying from 0-40% at 10% interval. It was observed that the tensile strength of the bio-composites decreased with increase in filler content with a maximum value of 31.24MPa at 10% filler content. The tensile modulus recorded an increase with increase in filler content with a maximum value of 2505MPa at 40% filler content while the maximum hardness stood at 72.9HRR at 30% filler content. The alkali treated bio-composites exhibited better properties as compared to those of the untreated ones.

Method and composition for testing for the presence of an alkali metal

International Nuclear Information System (INIS)

Guon, J.

1981-01-01

A method and composition for detecting the presence of an alkali metal on the surface of a body such as a metal plate, tank, pipe or the like is provided. The method comprises contacting the surface with a thin film of a liquid composition comprising a light-colored pigment, an acid-base indicator, and a nonionic wetting agent dispersed in a liquid carrier comprising a minor amount of water and a major amount of an organic solvent selected from the group consisting of the lower aliphatic alcohols, ketones and ethers. Any alkali metal present on the surface in elemental form or as an alkali metal hydroxide or alkali metal carbonate will react with the acid-base indicator to produce a contrasting color change in the thin film, which is readily discernible by visual observation or automatic techniques

Alkali-Resistant Mechanism of a Hollandite DeNOx Catalyst.

Science.gov (United States)

Hu, Pingping; Huang, Zhiwei; Gu, Xiao; Xu, Fei; Gao, Jiayi; Wang, Yue; Chen, Yaxin; Tang, Xingfu

2015-06-02

A thorough understanding of the deactivation mechanism by alkalis is of great importance for rationally designing improved alkali-resistant deNOx catalysts, but a traditional ion-exchange mechanism cannot often accurately describe the nature of the deactivation, thus hampering the development of superior catalysts. Here, we establish a new exchange-coordination mechanism on the basis of the exhaustive study on the strong alkali resistance of a hollandite manganese oxide (HMO) catalyst. A combination of isothermal adsorption measurements of ammonia with X-ray absorption near-edge structure spectra and X-ray photoelectron spectra reveals that alkali metal ions first react with protons from Brønsted acid sites of HMO via the ion exchange. Synchrotron X-ray diffraction patterns and extended X-ray absorption fine structure spectra coupled with theoretical calculations demonstrate that the exchanged alkali metal ions are subsequently stabilized at size-suitable cavities in the HMO pores via a coordination model with an energy savings. This exchange-coordination mechanism not only gives a wholly convincing explanation for the intrinsic nature of the deactivation of the reported catalysts by alkalis but also provides a strategy for rationally designing improved alkali-resistant deNOx catalysts in general.

Pretreatment of corn stover for sugar production using dilute hydrochloric acid followed by lime.

Science.gov (United States)

Zu, Shuai; Li, Wen-zhi; Zhang, Mingjian; Li, Zihong; Wang, Ziyu; Jameel, Hasan; Chang, Hou-min

2014-01-01

In this study, a two stage process was evaluated to increase the sugar recovery. Firstly, corn stover was treated with diluted hydrochloric acid to maximize the xylose yield, and then the residue was treated with lime to alter the lignin structure and swell the cellulose surface. The optimal condition was 120 °C and 40 min for diluted hydrochloric acid pretreatment followed by lime pretreatment at 60 °C for 12h with lime loading at 0.1 g/g of substrate. The glucose and xylose yield was 78.0% and 97.0%, respectively, with cellulase dosage at 5 FPU/g of substrate. The total glucose yield increased to 85.9% when the cellulase loading was increased to 10 FPU/g of substrate. This two stage process was effective due to the swelling of the internal surface, an increase in the porosity and a decrease in the degree of polymerization. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effect of Rice Straw Extract and Alkali Lignin on the Corrosion Inhibition of Carbon Steel

International Nuclear Information System (INIS)

Rabiahtul Zulkafli; Norinsan Kamil Othman; Irman Abdul Rahman; Azman Jalar

2014-01-01

A paddy residue based corrosion inhibitor was prepared by treating finely powdered rice straw with aqueous ethanol under acid catalyst (0.01 M H 2 SO 4 ). Commercial alkali lignin was obtained from Sigma-Aldrich. Prior to the corrosion test, the extraction yield and alkali lignin was characterized via FTIR to determine the functional group. The effect of paddy residue extract and commercial alkali lignin on the corrosion inhibition of carbon steel in 1 M HCl was investigated through the weight loss method, potentiodynamic polarization technique and scanning electron microscopy (SEM). The corrosion inhibition efficiency of the extract and alkali lignin at different immersion times (3 h, 24 h and 42 h) was evaluated. The results show that the paddy waste extract exhibited lesser weight loss of carbon steel in the acidic medium in comparison to the commercial alkali lignin, suggesting that the paddy residue extract is more effective than the commercial alkali lignin in terms of its corrosion inhibition properties. The results obtained proves that the extract from paddy residue could serve as an effective inhibitor for carbon steel in acidic mediums. (author)

Effect of dilution and L-malic acid addition on bio-hydrogen production with Rhodopseudomonas palustris from effluent of an acidogenic anaerobic reactor

International Nuclear Information System (INIS)

Azbar, N.; Tuba, F.; Dokgoz, C.

2009-01-01

In this study, H 2 was produced in a two-stage biological process: I) first stage; the dark fermentation of cheese whey wastewater, which is rich in lactose, by mixed anaerobic culture grown at thermophilic temperature in a continuously running fermentor and ii) second stage; the photo-fermentation of the residual medium by R. palustris strain (DSM 127) at 31 o C under illumination of 150 W in batch mode, respectively. In the first part of the study, the effluent from the dark fermentation reactor was used either as it is (no dilution) or after dilution with distilled water at varying ratios such as 1/2 , 1/5, 1/10 (1 volume effluent/5 volume distilled water) before used in photo-fermentation experiments. In the second part of the study, L-malic acid at varying amounts was added into the hydrogen production medium in order to have L-malic acid concentrations ranging from 0 to 4 g/l. Non-diluted and pre-diluted mediums with or without L-malic acid addition were also tested for comparison purpose (as controls). Prior to the hydrogen production experiments, all samples were subjected to pH adjustment, (pH 6.7) and sterilized by autoclave at 121 o C for 15 min. In regards to the experiments in which the effect of dilution of the effluent from dark fermentation was studied, it was observed that dilution of the effluent from dark fermentation resulted in much better hydrogen productions. Among the dilution rates used, the experiments operated with 1/5 dilution ratio produced the best hydrogen production (241 ml H 2 / g COD fed ). On the other hand, it was seen that the mixing the effluent with L-malic acid (0 - 4 g/l) at increasing ratios (studied from 0% L-malic acid up to 100% by volume in the mixture) had further positive effect and improved the hydrogen production. The bioreactors containing only L-malic acid media resulted in the best hydrogen production (438 ml H 2 / g COD fed ). It was found that, undiluted raw cheese whey wastewater effluent from dark hydrogen

[Raman spectra of endospores of Bacillus subtilis by alkali stress].

Science.gov (United States)

Dong, Rong; Lu, Ming-qian; Li, Feng; Shi, Gui-yu; Huang, Shu-shi

2013-09-01

To research the lethal mechanism of spores stressed by alkali, laser tweezers Raman spectroscopy (LTRS) combined with principal components analysis (PCA) was used to study the physiological process of single spore with alkali stress. The results showed that both spores and germinated spores had tolerance with alkali in a certain range, but the ability of spores was obviously lower than that of spores due to the release of their Ca2+ -DPA which plays a key role in spores resistance as well as spores resistance to many stresses; A small amount of Ca2+ -DPA of spores was observed to release after alkali stress, however, the behavior of release was different with the normal Ca2+ -DPA release behavior induced by L-alanine; The data before and after alkali stress of the spores and g. spores with PCA reflected that alkali mainly injured the membrane of spores, and alkali could be easily enter into the inner structure of spores to damage the structure of protein backbone and injure the nucleic acid of spores. We show that the alkali could result in the small amount of Ca2+ -DPA released by destroying the member channel of spores.

High temperature dilute phosphoric acid pretreatment of corn stover for furfural and ethanol production

Science.gov (United States)

Furfural was produced from corn stover by one stage pretreatment process using dilute H3PO4 and solid residues following furfural production were used for ethanol production by Saccharomyces cerevisiae NRRL- Y2034. A series of experiments were conducted at varied temperatures (140-200 oC) and acid ...

Electrolytic method to make alkali alcoholates using ion conducting alkali electrolyte/separator

Science.gov (United States)

Joshi, Ashok V [Salt Lake City, UT; Balagopal, Shekar [Sandy, UT; Pendelton, Justin [Salt Lake City, UT

2011-12-13

Alkali alcoholates, also called alkali alkoxides, are produced from alkali metal salt solutions and alcohol using a three-compartment electrolytic cell. The electrolytic cell includes an anolyte compartment configured with an anode, a buffer compartment, and a catholyte compartment configured with a cathode. An alkali ion conducting solid electrolyte configured to selectively transport alkali ions is positioned between the anolyte compartment and the buffer compartment. An alkali ion permeable separator is positioned between the buffer compartment and the catholyte compartment. The catholyte solution may include an alkali alcoholate and alcohol. The anolyte solution may include at least one alkali salt. The buffer compartment solution may include a soluble alkali salt and an alkali alcoholate in alcohol.

Novel Pendant Benzene Disulfonic Acid Blended SPPO Membranes for Alkali Recovery: Fabrication and Properties.

Science.gov (United States)

Mondal, Abhishek N; Dai, Chunhua; Pan, Jiefeng; Zheng, Chunlei; Hossain, Md Masem; Khan, Muhammad Imran; Wu, Liang; Xu, Tongwen

2015-07-29

To reconcile the trade-off between separation performance and availability of desired material for cation exchange membranes (CEMs), we designed and successfully prepared a novel sulfonated aromatic backbone-based cation exchange precursor named sodium 4,4'-(((((3,3'-disulfo-[1,1'-biphenyl]-4,4'-diyl)bis(oxy)) bis(4,1-phenylene))bis(azanediyl))bis(methylene))bis(benzene-1,3-disulfonate) [DSBPB] from 4,4'-bis(4-aminophenoxy)-[1,1'-biphenyl]-3,3'-disulfonic acid [BAPBDS] by a three-step procedure that included sulfonation, Michael condensation followed by reduction. Prepared DSBPB was used to blend with sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (SPPO) to get CEMs for alkali recovery via diffusion dialysis. Physiochemical properties and electrochemical performance of prepared membranes can be tuned by varying the dosage of DSBPB. All the thermo-mechanical properties like DMA and TGA were investigated along with water uptake (WR), ion exchange capacity (IEC), dimensional stability, etc. The effect of DSBPB was discussed in brief in connection with alkali recovery and ion conducting channels. The SPPO/DSBPB membranes possess both high water uptake as well as ion exchange capacity with high thermo-mechanical stability. At 25 °C the dialysis coefficients (UOH) appeared to be in the range of 0.0048-0.00814 m/h, whereas the separation factor (S) ranged from 12.61 to 36.88 when the membranes were tested for base recovery in Na2WO4/NaOH waste solution. Prepared membranes showed much improved DD performances compared to traditional SPPO membrane and possess the potentiality to be a promising candidate for alkali recovery via diffusion dialysis.

Comparative metabolic responses and adaptive strategies of wheat (Triticum aestivum) to salt and alkali stress.

Science.gov (United States)

Guo, Rui; Yang, Zongze; Li, Feng; Yan, Changrong; Zhong, Xiuli; Liu, Qi; Xia, Xu; Li, Haoru; Zhao, Long

2015-07-07

It is well known that salinization (high-pH) has been considered as a major environmental threat to agricultural systems. The aim of this study was to investigate the differences between salt stress and alkali stress in metabolic profiles and nutrient accumulation of wheat; these parameters were also evaluated to determine the physiological adaptive mechanisms by which wheat tolerates alkali stress. The harmful effect of alkali stress on the growth and photosynthesis of wheat were stronger than those of salt stress. High-pH of alkali stress induced the most of phosphate and metal ions to precipitate; as a result, the availability of nutrients significantly declined. Under alkali stress, Ca sharply increased in roots, however, it decreased under salt stress. In addition, we detected the 75 metabolites that were different among the treatments according to GC-MS analysis, including organic acids, amino acids, sugars/polyols and others. The metabolic data showed salt stress and alkali stress caused different metabolic shifts; alkali stress has a stronger injurious effect on the distribution and accumulation of metabolites than salt stress. These outcomes correspond to specific detrimental effects of a highly pH environment. Ca had a significant positive correlation with alkali tolerates, and increasing Ca concentration can immediately trigger SOS Na exclusion system and reduce the Na injury. Salt stress caused metabolic shifts toward gluconeogenesis with increased sugars to avoid osmotic stress; energy in roots and active synthesis in leaves were needed by wheat to develop salt tolerance. Alkali stress (at high pH) significantly inhibited photosynthetic rate; thus, sugar production was reduced, N metabolism was limited, amino acid production was reduced, and glycolysis was inhibited.

Effect of dilution and L-malic acid addition on bio-hydrogen production with Rhodopseudomonas palustris from effluent of an acidogenic anaerobic reactor

Energy Technology Data Exchange (ETDEWEB)

Azbar, N.; Tuba, F.; Dokgoz, C. [Bioengineering Dept., Faculty of Engineering, Ege Univ., Izmir (Turkey)], E-mail: nuri.azbar@ege.edu.tr

2009-07-01

In this study, H{sub 2} was produced in a two-stage biological process: I) first stage; the dark fermentation of cheese whey wastewater, which is rich in lactose, by mixed anaerobic culture grown at thermophilic temperature in a continuously running fermentor and ii) second stage; the photo-fermentation of the residual medium by R. palustris strain (DSM 127) at 31{sup o}C under illumination of 150 W in batch mode, respectively. In the first part of the study, the effluent from the dark fermentation reactor was used either as it is (no dilution) or after dilution with distilled water at varying ratios such as 1/2 , 1/5, 1/10 (1 volume effluent/5 volume distilled water) before used in photo-fermentation experiments. In the second part of the study, L-malic acid at varying amounts was added into the hydrogen production medium in order to have L-malic acid concentrations ranging from 0 to 4 g/l. Non-diluted and pre-diluted mediums with or without L-malic acid addition were also tested for comparison purpose (as controls). Prior to the hydrogen production experiments, all samples were subjected to pH adjustment, (pH 6.7) and sterilized by autoclave at 121{sup o}C for 15 min. In regards to the experiments in which the effect of dilution of the effluent from dark fermentation was studied, it was observed that dilution of the effluent from dark fermentation resulted in much better hydrogen productions. Among the dilution rates used, the experiments operated with 1/5 dilution ratio produced the best hydrogen production (241 ml H{sub 2}/ g COD{sub fed}). On the other hand, it was seen that the mixing the effluent with L-malic acid (0 - 4 g/l) at increasing ratios (studied from 0% L-malic acid up to 100% by volume in the mixture) had further positive effect and improved the hydrogen production. The bioreactors containing only L-malic acid media resulted in the best hydrogen production (438 ml H{sub 2} / g COD{sub fed}). It was found that, undiluted raw cheese whey wastewater

Production of spent mushroom substrate hydrolysates useful for cultivation of Lactococcus lactis by dilute sulfuric acid, cellulase and xylanase treatment.

Science.gov (United States)

Qiao, Jian-Jun; Zhang, Yan-Fei; Sun, Li-Fan; Liu, Wei-Wei; Zhu, Hong-Ji; Zhang, Zhijun

2011-09-01

Spent mushroom substrate (SMS) was treated with dilute sulfuric acid followed by cellulase and xylanase treatment to produce hydrolysates that could be used as the basis for media for the production of value added products. A L9 (3(4)) orthogonal experiment was performed to optimize the acid treatment process. Pretreatment with 6% (w/w) dilute sulfuric acid at 120°C for 120 min provided the highest reducing sugar yield of 267.57 g/kg SMS. No furfural was detected in the hydrolysates. Exposure to 20PFU of cellulase and 200 XU of xylanase per gram of pretreated SMS at 40°C resulted in the release of 79.85 g/kg or reducing sugars per kg acid pretreated SMS. The dilute sulfuric acid could be recycled to process fresh SMS four times. SMS hydrolysates neutralized with ammonium hydroxide, sodium hydroxide, or calcium hydroxide could be used as the carbon source for cultivation of Lactococcus lactis subsp. lactis W28 and a cell density of 2.9×10(11)CFU/mL could be obtained. The results provide a foundation for the development of value-added products based on SMS. Copyright © 2011 Elsevier Ltd. All rights reserved.

Revealing the Molecular Structural Transformation of Hardwood and Softwood in Dilute Acid Flowthrough Pretreatment

Energy Technology Data Exchange (ETDEWEB)

Zhang, Libing; Pu, Yunqiao; Cort, John R.; Ragauskas, Arthur J.; Yang, Bin

2016-12-05

To better understand the intrinsic recalcitrance of lignocellulosic biomass, the main hurdle to its efficient deconstruction, the effects of dilute acid flowthrough pretreatment on the dissolution chemistry of hemicellulose, cellulose, and lignin for both hardwood (e.g. poplar wood) and softwood (e.g. lodgepole pine wood) were investigated at temperatures of 200 °C to 270 °C and a flow rate of 25 mL/minute with 0.05% (w/w) H2SO4. Results suggested that the softwood cellulose was more readily to be degraded into monomeric sugars than that of hardwood under same pretreatment conditions. However, while the hardwood lignin was completely removed into hydrolysate, ~30% of the softwood lignin remained as solid residues under identical conditions, which was plausibly caused by vigorous C5-active recondensation reactions (C-C5). Unique molecular structural features that pronounced the specific recalcitrance of hardwood and softwood to dilute acid pretreatment were identified for the first time in this study, providing important insights to establish the effective biomass pretreatment.

The Study of Anti-/Pro-Oxidant, Lipophilic, Microbial and Spectroscopic Properties of New Alkali Metal Salts of 5-O-Caffeoylquinic Acid

Directory of Open Access Journals (Sweden)

Monika Kalinowska

2018-02-01

Full Text Available Lithium, sodium, potassium, rubidium and caesium salts of 5-O-caffeoylquinic acid (chlorogenic acid, 5-CQA were synthesized and described by FT-IR (infrared spectroscopy, FT-Raman (Raman spectroscopy, UV (UV absorption spectroscopy, 1H (400.15 MHz, 13C (100.63 MHz NMR (nuclear magnetic resonance spectroscopy. The quantum–chemical calculations at the B3LYP/6-311++G** level were done in order to obtain the optimal structures, IR spectra, NBO (natural bond orbital atomic charges, HOMO (highest occupied molecular orbital and LUMO (lowest unoccupied molecular orbital orbitals and chemical reactivity parameters for 5-CQA and Li, Na and K 5-CQAs (chlorogenates. The DPPH (α, α-diphenyl-β-picrylhydrazyl and FRAP (ferric reducing antioxidant power assays were used for the preliminary estimation of the antioxidant properties of alkali metal chlorogenates and chlorogenic acid. In the DPPH assay the EC50 parameter were equal to 7.39 μM for 5-CQA and was in the range of 4.50–5.89 μM for salts. The FRAP values for two different concentrations (5 and 2.5 μM of the studied compounds were respectively 114.22 and 72.53 μM Fe2+ for 5-CQA, whereas for salts they were 106.92–141.13 and 78.93–132.00 μM Fe2+. The 5-CQA and its alkali metal salts possess higher antioxidant properties than commonly applied antioxidants (BHA, BHT, l-ascorbic acid. The pro-oxidant action of these compounds on trolox oxidation was studied in the range of their concentration 0.05–0.35 μM. The lipophilicity (logkw of chlorogenates and chlorogenic acid was determined by RP-HPLC (reverse phase—high performance liquid chromatography using five different columns (C8, PHE (phenyl, CN (cyano, C18, IAM (immobilized artificial membrane. The compounds were screened for their in vitro antibacterial activity against E. coli, Bacillus sp., Staphylococcus sp., Streptococcus pyogenes and antifungal activity against Candida sp. The 5-CQA possessed lower antibacterial (minimal inhibitory

Physiologic actions of zinc related to inhibition of acid and alkali production by oral streptococci in suspensions and biofilms.

Science.gov (United States)

Phan, T-N; Buckner, T; Sheng, J; Baldeck, J D; Marquis, R E

2004-02-01

Zinc is a known inhibitor of acid production by mutans streptococci. Our primary objective was to extend current knowledge of the physiologic bases for this inhibition and also for zinc inhibition of alkali production by Streptococcus rattus FA-1 and Streptococcus salivarius ATCC 13419. Zinc at concentrations as low as 0.01-0.1 mm not only inhibited acid production by cells of Streptococcus mutans GS-5 in suspensions or in biofilms but also sensitized glycolysis by intact cells to acidification. Zinc reversibly inhibited the F-ATPase of permeabilized cells of S. mutans with a 50% inhibitory concentration of about 1 mm for cells in suspensions. Zinc reversibly inhibited the phosphoenolpyruvate: sugar phosphotransferase system with 50% inhibition at about 0.3 mm ZnSO4, or about half that concentration when the zinc-citrate chelate was used. The reversibility of these inhibitory actions of zinc correlates with findings that it is mainly bacteriostatic rather than bactericidal. Zinc inhibited alkali production from arginine or urea and was a potent enzyme inhibitor for arginine deiminase of S. rattus FA-1 and for urease of S. salivarius. In addition, zinc citrate at high levels of 10-20 mm was weakly bactericidal.

Comparison of Dilute Acid and Ionic Liquid Pretreatment of Switchgrass: Biomass Recalcitrance, Delignification and Enzymatic Saccharification

Science.gov (United States)

The efficiency of two biomass pretreatment technologies, dilute acid hydrolysis and dissolution in an ionic liquid, are compared in terms of delignification, saccharification efficiency and saccharide yields with switchgrass serving as a model bioenergy crop. When subject to ionic liquid pretreatme...

Alkali metals in addition to acidic pH activate the EvgS histidine kinase sensor in Escherichia coli.

Science.gov (United States)

Eguchi, Yoko; Utsumi, Ryutaro

2014-09-01

Two-component signal transduction systems (TCSs) in bacteria perceive environmental stress and transmit the information via phosphorelay to adjust multiple cellular functions for adaptation. The EvgS/EvgA system is a TCS that confers acid resistance to Escherichia coli cells. Activation of the EvgS sensor initiates a cascade of transcription factors, EvgA, YdeO, and GadE, which induce the expression of a large group of acid resistance genes. We searched for signals activating EvgS and found that a high concentration of alkali metals (Na(+), K(+)) in addition to low pH was essential for the activation. EvgS is a histidine kinase, with a large periplasmic sensor region consisting of two tandem PBPb (bacterial periplasmic solute-binding protein) domains at its N terminus. The periplasmic sensor region of EvgS was necessary for EvgS activation, and Leu152, located within the first PBPb domain, was involved in the activation. Furthermore, chimeras of EvgS and PhoQ histidine kinases suggested that alkali metals were perceived at the periplasmic sensor region, whereas the cytoplasmic linker domain, connecting the transmembrane region and the histidine kinase domain, was required for low-pH perception. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Dilute-acid hydrolysis of apple, orange, apricot and peach pomaces as potential candidates for bioethanol production

OpenAIRE

Üçüncü, Can; Tarı, Canan; Demir, Hande; Büyükkileci, Ali Oğuz; Özen, Banu

2013-01-01

Chemical composition of four selected fruit pomaces (agro-industrial wastes) was evaluated. The effect of temperature, time, acid concentration and solid:liquid (S:L) ratio on dilute-acid hydrolysis of selected pomaces were investigated using 24 factorial and central composite design and optimum hydrolysis conditions were determined. A preliminary study was initiated using apple hydrolysate and the fungus Tricoderma harzianum in order to explore and demonstrate their potential uses in bioetha...

Dilute acid pretreatment of rye straw and bermudagrass for ethanol production

Energy Technology Data Exchange (ETDEWEB)

Ye Sun; Jay J Cheng [North Carolina State Univ., Dept. of Biological and Agricultural Engineering, Raleigh, NC (United States)

2005-09-01

Ethanol production from lignocellulosic materials provides an alternative energy production system. Rye and bermudagrass that are used in hog farms for nutrient uptake from swine wastewater have the potential for fuel ethanol production because they have a relative high cellulose and hemicellulose content. Dilute sulfuric acid pretreatment of rye straw and bermudagrass before enzymatic hydrolysis of cellulose was investigated in this study. The biomass at a solid loading rate of 10% was pretreated at 121 deg C with different sulfuric acid concentrations (0.6, 0.9, 1.2 and 1.5%, w/w) and residence times (30, 60, and 90 min). Total reducing sugars, arabinose, galactose, glucose, and xylose in the prehydrolyzate were analyzed. In addition, the solid residues were hydrolyzed by cellulases to investigate the enzymatic digestibility. With the increasing acid concentration and residence time, the amount of arabinose and galactose in the filtrates increased. The glucose concentration in the prehydrolyzate of rye straw was not significantly influenced by the sulfuric acid concentration and residence time, but it increased in the prehydrolyzate of bermudagrass with the increase of pretreatment severity. The xylose concentration in the filtrates increased with the increase of sulfuric acid concentration and residence time. Most of the arabinan, galactan and xylan in the biomass were hydrolyzed during the acid pretreatment. Cellulose remaining in the pretreated feedstock was highly digestible by cellulases from Trichoderma reesei. (Author)

Dissolution of magnetite in a dilute chemical decontaminant formulation containing gallic acid as a reductant

International Nuclear Information System (INIS)

Kishore, Kamal; Rajesh, Puspalata; Dey, G.R.

2000-01-01

Gallic acid (GA) was tried as a reductant in place of ascorbic acid in dilute chemical decontaminant (DCD) formulations. Dissolution of magnetite in GA based DCD formulations was studied at 50 deg as well as 80 degC. It was found to be a good substitute for ascorbic acid in EDTA/ascorbic acid/citric acid i.e. EAC formulation. The efficiency of EDTA/GA/CA formulation was as good as that of EAC formulation. 2.8 was found to be the optimum pH for this formulation and dissolution decreased at lower as well as higher pHs. The ion-exchange behaviour of GA is also appropriate for using it in a regenerating type of formulation. Being an aromatic compound, gallic acid has inherent stability against radiation degradation. (author)

Separation of glycols from dilute aqueous solutions via complexation with boronic acids

Energy Technology Data Exchange (ETDEWEB)

Randel, L.A.; King, C.J.

1991-07-01

This work examines methods of separating low molecular weight glycols from dilute aqueous solution. Extraction into conventional solvents is generally not economical, since, in the literature reviewed, distribution ratios for the two- to four-carbon glycols are all less than one. Distribution ratios can be increased, however, by incorporating into the organic phase an extracting agent that will complex with the solute of interest. The extracting agent investigated in this work is 3-nitrophenylboronic acid (NPBA). NPBA, a boric acid derivative, reversibly complexes with many glycols. The literature on complexation of borate and related compounds with glycols, including mechanistic data, measurement techniques, and applications to separation processes, provides information valuable for designing experiments with NPBA and is reviewed herein. 88 refs., 15 figs., 24 tabs.

Titanium leaching from red mud by diluted sulfuric acid at atmospheric pressure

International Nuclear Information System (INIS)

Agatzini-Leonardou, S.; Oustadakis, P.; Tsakiridis, P.E.; Markopoulos, Ch.

2008-01-01

Laboratory-scale research has focused on the recovery of titanium from red mud, which is obtained from bauxite during the Bayer process for alumina production. The leaching process is based on the extraction of this element with diluted sulfuric acid from red mud under atmospheric conditions and without using any preliminary treatment. Statistical design and analysis of experiments were used, in order to determine the main effects and interactions of the leaching process factors, which were: acid normality, temperature and solid to liquid ratio. The titanium recovery efficiency on the basis of red mud weight reached 64.5%. The characterization of the initial red mud, as well as this of the leached residues was carried out by X-ray diffraction, TG-DTA and scanning electron microscopy

Alkali-treated titanium selectively regulating biological behaviors of bacteria, cancer cells and mesenchymal stem cells.

Science.gov (United States)

Li, Jinhua; Wang, Guifang; Wang, Donghui; Wu, Qianju; Jiang, Xinquan; Liu, Xuanyong

2014-12-15

Many attentions have been paid to the beneficial effect of alkali-treated titanium to bioactivity and osteogenic activity, but few to the other biological effect. In this work, hierarchical micro/nanopore films were prepared on titanium surface by acid etching and alkali treatment and their biological effects on bacteria, cancer cells and mesenchymal stem cells were investigated. Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and human cholangiocarcinoma cell line RBE were used to investigate whether alkali-treated titanium can influence behaviors of bacteria and cancer cells. Responses of bone marrow mesenchymal stem cells (BMMSCs) to alkali-treated titanium were also subsequently investigated. The alkali-treated titanium can potently reduce bacterial adhesion, inhibit RBE and BMMSCs proliferation, while can better promote BMMSCs osteogenesis and angiogenesis than acid-etched titanium. The bacteriostatic ability of the alkali-treated titanium is proposed to result from the joint effect of micro/nanotopography and local pH increase at bacterium/material interface due to the hydrolysis of alkali (earth) metal titanate salts. The inhibitory action of cell proliferation is thought to be the effect of local pH increase at cell/material interface which causes the alkalosis of cells. This alkalosis model reported in this work will help to understand the biologic behaviors of various cells on alkali-treated titanium surface and design the intended biomedical applications. Copyright © 2014 Elsevier Inc. All rights reserved.

Beech wood Fagus sylvatica dilute-acid hydrolysate as a feedstock to support Chlorella sorokiniana biomass, fatty acid and pigment production.

Science.gov (United States)

Miazek, Krystian; Remacle, Claire; Richel, Aurore; Goffin, Dorothee

2017-04-01

This work evaluates the possibility of using beech wood (Fagus sylvatica) dilute-acid (H 2 SO 4 ) hydrolysate as a feedstock for Chlorella sorokiniana growth, fatty acid and pigment production. Neutralized wood acid hydrolysate, containing organic and mineral compounds, was tested on Chlorella growth at different concentrations and compared to growth under phototrophic conditions. Chlorella growth was improved at lower loadings and inhibited at higher loadings. Based on these results, a 12% neutralized wood acid hydrolysate (Hyd12%) loading was selected to investigate its impact on Chlorella growth, fatty acid and pigment production. Hyd12% improved microalgal biomass, fatty acid and pigment productivities both in light and in dark, when compared to photoautotrophic control. Light intensity had substantial influence on fatty acid and pigment composition in Chlorella culture during Hyd12%-based growth. Moreover, heterotrophic Chlorella cultivation with Hyd12% also showed that wood hydrolysate can constitute an attractive feedstock for microalgae cultivation in case of lack of light. Copyright © 2017 Elsevier Ltd. All rights reserved.

Recovery of acids from dilute streams : A review of process technologies

International Nuclear Information System (INIS)

Talnikar, Vivek Digambar; Mahajan, Yogesh Shankar

2014-01-01

Chemical process industries convert raw materials into useful products. Acids, among other chemicals, are used in many industries as reactants, solvents and also as catalysts in a few instances as well. Resulting streams are dilute, from which the acids must be recovered. For recovery, many technologies can be used by which acids can be regained as such or can be converted into other value-added products like esters. Membrane processes and biological processes are being researched academically and practiced industrially. These have their own advantages and disadvantages in view of conversion, energy consumption etc. These are not always advantageous and hence an alternate process technology is necessary like reactive separation (RS). RS is advantageous especially when the acid is to be converted to other useful products by reaction, due to additional advantages or because no other technology is well suited or due to cost considerations alone. Conventional process technologies use the reactor configuration followed by the subsequent separation sequence. This approach can sometimes suffer from lesser conversion, difficulties in separation etc. To overcome these problems, RS has an edge over other processes in terms of the recovery of the useful compounds. Reactive distillation (RD), reactive extraction (RE) and reactive chromatography (RC) are the separation technologies that can be useful for acid recovery in an economically feasible way. This review covers the various processes of acid recovery along with the recent work in the field of reactive separations

1-D Compression Behaviour of Acid Sulphate Soils Treated with Alkali-Activated Slag.

Science.gov (United States)

Islam, Shahidul; Haque, Asadul; Bui, Ha Hong

2016-04-15

Improvements of soft soils by mechanically mixing cementitious additives have been widely practised for construction of infrastructure. Mixing of additives improves strength and compressibility properties of soils through the development of soil structure. This study investigates the 1-D compression behaviour of alkali-activated slag treated acid sulphate soils (ASS) cured up to 365 days. The void ratio-logarithm of pressure (e-logσ') behaviour of treated ASS, including the destructuration behaviour, with additive contents and curing time have been analysed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses have been undertaken to explain the observed variations of the 1-D compression behaviour. This paper presents the results of these analyses in view of obtaining an insight into the 1-D compression behaviour of treated ASS with the help of mineralogical analysis.

Alkali silica reaction (ASR) in cement free alkali activated sustainable concrete.

Science.gov (United States)

2016-12-19

This report summarizes the findings of an experimental evaluation into alkali silica : reaction (ASR) in cement free alkali-activated slag and fly ash binder concrete. The : susceptibility of alkali-activated fly ash and slag concrete binders to dele...

Process to separate alkali metal salts from alkali metal reacted hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Gordon, John Howard; Alvare, Javier; Larsen, Dennis; Killpack, Jeff

2017-06-27

A process to facilitate gravimetric separation of alkali metal salts, such as alkali metal sulfides and polysulfides, from alkali metal reacted hydrocarbons. The disclosed process is part of a method of upgrading a hydrocarbon feedstock by removing heteroatoms and/or one or more heavy metals from the hydrocarbon feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase containing alkali metal salts and reduced heavy metals, and an upgraded hydrocarbon feedstock. The inorganic phase may be gravimetrically separated from the upgraded hydrocarbon feedstock after mixing at a temperature between about 350.degree. C. to 400.degree. C. for a time period between about 15 minutes and 2 hours.

The urinary excretion of orotic acid and orotidine, measured by an isotope dilution assay

International Nuclear Information System (INIS)

Tax, W.J.M.; Veerkamp, J.H.; Schretlen, E.D.A.M.

1978-01-01

Unknown concentrations of orotic acid can be measured by competition with a known amount of [carboxyl- 14 C]orotic acid for reaction with a limiting amount of phosphoribosylpyrophosphate in the presence of orotate phosphoribosyltransferase and orotidine monophosphate decarboxylase. The dilution of the specific radioactivity in the product 14 CO 2 is a sensitive and accurate measure of the amount of orotic acid present in the sample. Orotidine can also be determined after hydrolytic cleavage to orotic acid. The method was used to measure orotic acid and orotidine in urine samples from newborns, healthy controls and patients with gout or deficiency of hypoxanthine-guanine phosphoribosyltransferase receiving allopurinol. Urinary excretion of orotic acid and orotidine in newborns was similar whether the infants were breast-fed or received milk powder. The excretion of orotidine was increased in all patients receiving allopurinol. After allopurinol administration orotic acid excretion was increased in gouty patients but close to normal values in patients with deficiency of hypoxanthine-guanine phosphoribosyltransferase. The results are discussed in relation to the mechanism by which allopurinol inhibits pyrimidine metabolism. (Auth.)

Petrography study on altered flint aggregate by alkali-silica reaction

International Nuclear Information System (INIS)

Bulteel, D.; Rafai, N.; Degrugilliers, P.; Garcia-Diaz, E.

2004-01-01

The aim of our study is to improve our understanding of an alkali-silica reaction (ASR) via petrography. We used a chemical concrete subsystem: flint aggregate, portlandite and KOH. The altered flint aggregate is followed by optical microscopy and scanning electron microscopy (SEM) before and after acid treatment at different intervals. After acid treatment, the observations showed an increase in aggregate porosity and revealed internal degradation of the aggregate. This degradation created amorphous zones. Before acid treatment, the analyses on polished sections by scanning electron microscopy coupled with energy dispersive spectroscopy (EDS) enabled visualization of K + and Ca 2+ penetration into the aggregate. The appearance of amorphous zones and penetration of positive ions into the aggregate are correlated with the increase in the molar fraction of silanol sites. This degradation is specific to the alkali-silica reaction

Facile preparation of super-hydrophilic poly(ethylene terephthalate) fabric using dilute sulfuric acid under microwave irradiation

Energy Technology Data Exchange (ETDEWEB)

Xu, Fang [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Guangxian, E-mail: zgx656472@sina.com.cn [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China); Zhang, Fengxiu [College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400715 (China); Zhang, Yuansong [College of Textiles and Garments, Southwest University, Chongqing 400715 (China); Chongqing Engineering Research Center of Biomaterial Fiber and Modern Textile, Chongqing 400715 (China)

2015-09-15

Highlights: • A durable super-hydrophilic PET fabric was prepared using dilute H{sub 2}SO{sub 4} under microwave irradiation. • Dilute sulfuric acid was gradually concentrated enough to sulfonate PET fabric. • Microwave irradiation made PET fabric modification highly efficient. • The mechanical properties of modified PET fibers were kept well. • The method was novel, rapid, and eco-friendly. - Abstract: The hydrophilicity of a poly(ethylene terephthalate) (PET) fabric was greatly modified by using dilute sulfuric acid, which gradually became concentrated enough to sulfonate the fabric when microwave irradiation (MW) was applied. The modified PET fabric was super-hydrophilic. Modifying the fabric caused the water contact angle to decrease from 132.46 (for the unmodified fabric) to 0°, the water absorption rate to increase from 36.45 to 119.78%, and the capillary rise height to increase from 0.4 to 14.4 cm. The hydrophilicity of the modified PET fabric was not affected by washing it many times. Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses showed that there were sulfonic acid groups on the modified fibers. Almost no difference between the surfaces of the unmodified and modified PET fibers was found using scanning electron microscopy. Analysis by differential scanning calorimetry showed that the unmodified and modified fabrics had similar thermostabilities. X-ray diffraction analysis of the crystalline structures of the unmodified and modified fibers showed that they were almost the same. The strength, elasticity, and rigidity of the unmodified fabric were retained by the modified fabric. The modified fabric had better dyeing properties than the unmodified fabric.

Dilute chemical decontamination program review

International Nuclear Information System (INIS)

Anstine, L.D.; Blomgren, J.C.; Pettit, P.J.

1980-01-01

The objective of the Dilute Chemical Decontamination Program is to develop and evaluate a process which utilizes reagents in dilute concentrations for the decontamination of BWR primary systems and for the maintenance of dose rates on the out-of-core surfaces at acceptable levels. A discussion is presented of the process concept, solvent development, advantages and disadvantages of reagent systems, and VNC loop tests. Based on the work completed to date it is concluded that (1) rapid decontamination of BWRs using dilute reagents is feasible; (2) reasonable reagent conditions for rapid chemical decontamination are: 0.01M oxalic acid + 0.005M citric acid, pH3.0, 90/degree/C, 0.5 to 1.0 ppm dissolved oxygen; (3) control of dissolved oxygen concentration is important, since high levels suppress the rate of decontamination and low levels allow precipitation of ferrous oxalate. 4 refs

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability.

Science.gov (United States)

Bsat, Suzan; Yavari, Saber Amin; Munsch, Maximilian; Valstar, Edward R; Zadpoor, Amir A

2015-04-08

Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH) treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M) and immersion times (6, 24 h) of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF) immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200-300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

Directory of Open Access Journals (Sweden)

Suzan Bsat

2015-04-01

Full Text Available Advanced additive manufacturing techniques such as electron beam melting (EBM, can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M and immersion times (6, 24 h of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200–300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

Dilute Sulfuric Acid Pretreatment of Agricultural and Agro-Industrial Residues for Ethanol Production

Science.gov (United States)

Martin, Carlos; Alriksson, Björn; Sjöde, Anders; Nilvebrant, Nils-Olof; Jönsson, Leif J.

The potential of dilute-acid prehydrolysis as a pretreatment method for sugarcane bagasse, rice hulls, peanut shells, and cassava stalks was investigated. The prehydrolysis was performed at 122°C during 20, 40, or 60 min using 2% H2SO4 at a solid-to-liquid ratio of 1∶10. Sugar formation increased with increasing reaction time. Xylose, glucose, arabinose, and galactose were detected in all of the prehydrolysates, whereas mannose was found only in the prehydrolysates of peanut shells and cassava stalks. The hemicelluloses of bagasse were hydrolyzed to a high-extent yielding concentrations of xylose and arabinose of 19.1 and 2.2 g/L, respectively, and a xylan conversion of more than 80%. High-glucose concentrations (26-33.5 g/L) were found in the prehydrolysates of rice hulls, probably because of hydrolysis of starch of grain remains in the hulls. Peanut shells and cassava stalks rendered low amounts of sugars on prehydrolysis, indicating that the conditions were not severe enough to hydrolyze the hemicelluloses in these materials quantitatively. All prehydrolysates were readily fermentable by Saccharomyces cerevisiae. The dilute-acid prehydrolysis resulted in a 2.7-to 3.7-fold increase of the enzymatic convertibility of bagasse, but was not efficient for improving the enzymatic hydrolysis of peanut shells, cassava stalks, or rice hulls.

Water-based adhesives with tailored hydrophobic association: dilution resistance and improved setting behavior.

Science.gov (United States)

Dundua, Alexander; Landfester, Katharina; Taden, Andreas

2014-11-01

Hydrophobic association and stimuli-responsiveness is a powerful tool towards water-based adhesives with strongly improved properties, which is demonstrated based on the example of hydrophobically modified alkali-soluble latexes (HASE) with modulated association. Their rheological properties are highly tunable due to the hydrophobic domains that act as physical crosslinking sites of adjustable interaction strength. Ethanol, propanol, and butanol are used as water-soluble model additives with different hydrophobicity in order to specifically target the association sites and impact the viscoelastic properties and stimuli-responsiveness. The rheological and mechanical property response upon dilution with water can be tailored, and dilution-resistant or even dilution-thickening systems are obtained. The investigations are of high importance for water-based adhesives, as our findings provide insight into general structure-property relationships to improve their setting behavior, especially upon contact with wet substrates. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Impact of saline-alkali stress on the accumulation of solids in tomato fruits

International Nuclear Information System (INIS)

Jan, N.E.; Din, J.U.; Kawabata, S

2014-01-01

Growing of tomato plants in saline conditions, having high rhizospheric EC, is often reported with high solid content in fruits. However, saline-alkali stress conditions, having high rhizospheric pH as well as high EC, have never been studied to evaluate its impact on the solid content of tomato fruits. In this study, we investigated the impact of saline-alkali stress (0, 30, 60, 90, and 120 mM NaHCO/sub 3/) on the accumulation of solids in tomato fruits. Addition of sodium bicarbonate (NaHCO/sub 3/) to plants highly increased pH as well as EC of the soil leachate in 90 and 120 mM NaHCO/sub 3/ treatments in comparison to control treatment. Saline-alkali stress treatments did not influence the fruit dry weight, nonetheless, the content of fruit dry matter was increased significantly from 6.5% at control to 8.5% at 90 and 120 mM treatments. The content of soluble sugar was increased to 3% in 90 mM treatment in comparison to control (2%), owing to significant accumulation of hexose as well as sucrose in ripe fruits. In addition to carbohydrates, saline-alkali stress influenced the accumulation of organic acids in fruits, as well. Citric acid, being the major acid, showed positive correlation with the salt concentration, and was significantly high at stress treatments of higher than 30 mM. These results suggested that saline-alkali stress conditions, in spite of high pH, can increase the contents of fruit solids in tomato, as is usually observed in saline stress conditions. (author)

Alkali-Activated Natural Pozzolan/Slag Binder for Sustainable Concrete

Science.gov (United States)

Najimi, Meysam

This study aimed to fully replace Portland cement (PC) with environmentally friendly binders capable of improving longevity of concrete. The new binders consisted of different proportions of natural Pozzolan and slag which were alkaline-activated with various combinations of sodium hydroxide and sodium silicate. A step-by-step research program was designed to (1) develop alkali-activated natural Pozzolan/slag pastes with adequate fresh and strength properties, (2) produce alkali-activated natural Pozzolan/slag mortars to assess the effects of dominant variables on their plastic and hardened properties, and (3) finally produce and assess fresh, mechanical, dimensional, transport and durability properties of alkali-activated natural Pozzolan/slag concretes. The major variables included in this study were binder combination (natural Pozzolan/slag combinations of 70/30, 50/50 and 30/70), activator combination (sodium silicate/sodium hydroxide combinations of 20/80, 25/75 and 30/70), and sodium hydroxide concentration (1, 1.75 and 2.5M). The experimental program assessed performance of alkali-activated natural Pozzolan/slag mixtures including fresh properties (flow and setting times), unit weights (fresh, demolded and oven-dry), mechanical properties (compressive and tensile strengths, and modulus of elasticity), transport properties (absorption, rapid chloride penetration, and rapid chloride migration), durability (frost resistance, chloride induced corrosion, and resistance to sulfuric acid attack), and dimensional stability (drying shrinkage). This study also compared the performance of alkali-activated natural Pozzolan/slag concretes with that of an equivalent reference Portland cement concrete having a similar flow and strength characteristics. The results of this study revealed that it was doable to find optimum binder proportions, activator combinations and sodium hydroxide concentrations to achieve adequate plastic and hardened properties. Nearly for all studied

Heteropoly acid promoted V2O5/TiO2 catalysts for NO abatement with ammonia in alkali containing flue gases

DEFF Research Database (Denmark)

Putluru, Siva Sankar Reddy; Jensen, Anker Degn; Riisager, Anders

2011-01-01

V2O5/TiO2 and heteropoly acid promoted V2O5/TiO2 catalysts were prepared and characterized by N2 physisorption, XRPD and NH3-TPD. The influence of the calcination temperature from 400 to 700 1C on crystallinity and acidic properties was studied and compared with the activity for the selective...... catalytic reduction (SCR) of NO with ammonia. The SCR activity of heteropoly acid promoted catalysts was found to be much higher than for unpromoted catalysts. The stability of heteropoly acid promoted catalysts is dependent on calcination temperature and there is a gradual decrease in SCR activity...... and acidity with increase in calcination temperatures. Furthermore, the heteropoly acid promoted V2O5/TiO2 catalysts showed excellent alkali deactivation resistance and might therefore be alternative deNOx catalysts in biomass fired power plants....

Changes in lignocellulosic supramolecular and ultrastructure during dilute acid pretreatment of Populus and switchgrass

International Nuclear Information System (INIS)

Foston, Marcus; Ragauskas, Art J.

2010-01-01

Dilute acid pretreatment (DAP) is commonly employed prior to enzymatic deconstruction of cellulose to increase overall sugar and subsequent ethanol yields from downstream bioconversion processes. Typically optimization of pretreatment is evaluated by determining hemicellulose removal, subsequent reactivity towards enzymatic deconstruction, and recoverable polysaccharide yields. In this study, the affect of DAP on the supramolecular and ultrastructure of lignocellulosic biomass was evaluated. A series of dilute acidic pretreatments, employing ∼0.10-0.20 mol/m 3 H 2 SO 4 at ∼160-180 o C, for varying residence times were conducted on both Populus and switchgrass samples. The untreated and pretreated biomass samples were characterized by carbohydrate and lignin analysis, gel permeation chromatography (GPC) and 13 C cross polarization magic angle spinning (CPMAS) NMR spectroscopy. GPC analysis shows a reduction in the molecular weight of cellulose and change in its polydispersity index (PDI) with increasing residence time, indicating that pretreatment is actually degrading the cellulose chains. 13 C CPMAS and non-linear line-fitting of the C 4 region in the carbon spectrum of the isolated cellulose not only showed that the crystallinity index increases with residence time, but that the lateral fibril dimension (LFD) and lateral fibril aggregate dimension (LFAD) increase as well.

1-D Compression Behaviour of Acid Sulphate Soils Treated with Alkali-Activated Slag

Directory of Open Access Journals (Sweden)

Shahidul Islam

2016-04-01

Full Text Available Improvements of soft soils by mechanically mixing cementitious additives have been widely practised for construction of infrastructure. Mixing of additives improves strength and compressibility properties of soils through the development of soil structure. This study investigates the 1-D compression behaviour of alkali-activated slag treated acid sulphate soils (ASS cured up to 365 days. The void ratio-logarithm of pressure (e-logσ′ behaviour of treated ASS, including the destructuration behaviour, with additive contents and curing time have been analysed. X-ray diffraction (XRD and scanning electron microscopy (SEM analyses have been undertaken to explain the observed variations of the 1-D compression behaviour. This paper presents the results of these analyses in view of obtaining an insight into the 1-D compression behaviour of treated ASS with the help of mineralogical analysis.

Bioelectrochemical recovery of waste-derived volatile fatty acids and production of hydrogen and alkali.

Science.gov (United States)

Zhang, Yifeng; Angelidaki, Irini

2015-09-15

Volatile fatty acids (VFA) are organic compounds of great importance for various industries and environmental processes. Fermentation and anaerobic digestion of organic wastes are promising alternative technologies for VFA production. However, one of the major challenges is development of sustainable downstream technologies for VFA recovery. In this study, an innovative microbial bipolar electrodialysis cell (MBEDC) was developed to meet the challenge of waste-derived VFA recovery, produce hydrogen and alkali, and potentially treat wastewater. The MBEDC was operated in fed-batch mode. At an applied voltage of 1.2 V, a VFA recovery efficiency of 98.3%, H2 of 18.4 mL and alkali production presented as pH of 12.64 were obtained using synthetic fermentation broth. The applied voltage, initial VFA concentrations and composition were affecting the VFA recovery. The energy balance revealed that net energy (5.20-6.86 kWh/kg-VFA recovered) was produced at all the applied voltages (0.8-1.4 V). The coexistence of other anionic species had no negative effect on VFA transportation. The VFA concentration was increased 2.96 times after three consecutive batches. Furthermore, the applicability of MBEDC was successfully verified with digestate. These results demonstrate for the first time the possibility of a new method for waste-derived VFA recovery and valuable products production that uses wastewater as fuel and bacteria as catalyst. Copyright © 2015 Elsevier Ltd. All rights reserved.

Micropore surface area of alkali-soluble plant macromolecules (humic acids) drives their decomposition rates in soil.

Science.gov (United States)

Papa, Gabriella; Spagnol, Manuela; Tambone, Fulvia; Pilu, Roberto; Scaglia, Barbara; Adani, Fabrizio

2010-02-01

Previous studies suggested that micropore surface area (MSA) of alkali-soluble bio-macromolecules of aerial plant residues of maize constitutes an important factor that explains their humification in soil, that is, preservation against biological degradation. On the other hand, root plant residue contributes to the soil humus balance, as well. Following the experimental design used in a previous paper published in this journal, this study shows that the biochemical recalcitrance of the alkali-soluble acid-insoluble fraction of the root plant material, contributed to the root maize humification of both Wild-type maize plants and its corresponding mutant brown midrib (bm3), this latter characterized by reduced lignin content. Humic acids (HAs) existed in root (root-HAs) were less degraded in soil than corresponding HAs existed in shoot (shoot-HAs): shoot-HAs bm3 (48%)>shoot-HAs Wild-type (37%)>root-HAs Wild-type (33%)>root-HAs bm3 (22%) (degradability shown in parenthesis). These differences were related to the MSA of HAs, that is, root-HAs having a higher MSA than shoot-HAs: shoot-HAs bm3 (41.43+/-1.2m(2)g(-1))

Alkali roasting of bomar ilmenite: rare earths recovery and physico-chemical changes

Directory of Open Access Journals (Sweden)

Sanchez-Segado Sergio

2014-11-01

(FeTiO3 is presented as a process route for integrated beneficiation of the mineral for rutile-rich phase and rare earth oxides; the latter is released as a consequence of physical changes in the ilmenite matrix, during the water leaching after roasting. The oxidative alkali roasting transforms ilmenite mineral into water-insoluble alkali titanate and water-soluble ferrite. After roasting the insoluble alkali titanate is separated from rare-earth oxide mixture in colloidal form and water-soluble ferrite. Further leaching of alkali titanate is carried out with oxalic (0.3M and ascorbic (0.01M acid solution which removes the remaining Fe2+ ions into the leachate and allows precipitation of high-purity synthetic rutile containing more than 95% TiO2. Iron is removed as iron oxalate. The physico-chemical changes occurred during the roasting and leaching processes are reported by comparing the role of alkali on the roasting process and product morphologies formed.

Hydrolysis of R7T7 nuclear waste glass in dilute media: mechanisms and rate as a function of pH

International Nuclear Information System (INIS)

Advocat, T.; Vernaz, E.; Charpentier, H.; Crovisier, J.L.; Ehret, G.

1990-01-01

R7T7 nuclear waste glass dissolution in highly dilute aqueous media under static conditions at 90 0 C occurs according to two different mechanisms depending on the solution acidity. In acid media (pH 4.8 and 5.5), preferential extraction of glass network modifiers results in the formation of an alkali metal-depleted surface region on which amorphous and crystallized (phosphate) compounds rich in transition elements precipitate. Steady-state dissolution conditions are not reached, as attested by variable normalized Si, B and Na mass losses. Glass dissolution is stoichiometric in basic media (pH 7 to 10): the strong bonds of the silicated network are broken at a rate that increases with the pH: the glass dissolution rate increases by a factor of 15 between pH 7 and 10. Under these conditions, alteration products at the glass/solution interface do not constitute a short-term kinetic barrier against the release of the major glass components

Understanding longitudinal wood fiber ultra-structure for producing cellulose nanofibrils using disk milling with diluted acid prehydrolysis

Science.gov (United States)

Yanlin Qin; Xueqing Qiu; Junyong Zhu

2016-01-01

Here we used dilute oxalic acid to pretreat a kraft bleached Eucalyptus pulp (BEP) fibers to facilitate mechanical fibrillation in producing cellulose nanofibrils using disk milling with substantial mechanical energy savings. We successfully applied a reaction kinetics based combined hydrolysis factor (CHFx) as a severity factor to quantitatively...

Process for recovery and purification of lithium from dilute sources

International Nuclear Information System (INIS)

Kunugita, Eiichi; Kim, Jong-Hwa; Komasawa, Isao

1990-01-01

A process was studied for recovery and purification of lithium from hot spring water and leachate of coal fly ash in which lithium is present at very low concentration in a mixture of high concentration of less desirable species such as alkali metals, alkaline earth metals and others. Lithium is, as a first step, adsorbed selectively by an ion-sieve type adsorbent, λ-MnO 2 , which can effect separation by adsorbing lithium alone in its intraparticle spaces while adsorbing most metals on its surface. Stagewise elutions are performed, employing two elutrients: NH 4 NO 3 and then HNO 3 solution. The concentration ratio of lithium and sodium is 1/70∼1/120 in the original feed stream, and this is upgraded to 300/1 in the pregnant elutrient. Some impurities in the pregnant elutrient is removed by a solvent extraction technique, employing a mixed extractant of a β-diketone (LIX51) and tri-n-octyl-phosphine oxide in kerosene. A lithium solution with an undetectable amount of impurities is obtained by single extraction followed by single scrubbing with dilute hydrochloric acid of carefully controlled concentration. (author)

The impacts of pretreatment on the fermentability of pretreated lignocellulosic biomass: a comparative evaluation between ammonia fiber expansion and dilute acid pretreatment

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Dale Bruce E

2009-12-01

Full Text Available Abstract Background Pretreatment chemistry is of central importance due to its impacts on cellulosic biomass processing and biofuels conversion. Ammonia fiber expansion (AFEX and dilute acid are two promising pretreatments using alkaline and acidic pH that have distinctive differences in pretreatment chemistries. Results Comparative evaluation on these two pretreatments reveal that (i AFEX-pretreated corn stover is significantly more fermentable with respect to cell growth and sugar consumption, (ii both pretreatments can achieve more than 80% of total sugar yield in the enzymatic hydrolysis of washed pretreated solids, and (iii while AFEX completely preserves plant carbohydrates, dilute acid pretreatment at 5% solids loading degrades 13% of xylose to byproducts. Conclusion The selection of pretreatment will determine the biomass-processing configuration, requirements for hydrolysate conditioning (if any and fermentation strategy. Through dilute acid pretreatment, the need for hemicellulase in biomass processing is negligible. AFEX-centered cellulosic technology can alleviate fermentation costs through reducing inoculum size and practically eliminating nutrient costs during bioconversion. However, AFEX requires supplemental xylanases as well as cellulase activity. As for long-term sustainability, AFEX has greater potential to diversify products from a cellulosic biorefinery due to lower levels of inhibitor generation and lignin loss.

Selection of anion exchangers for detoxification of dilute-acid hydrolysates from spruce.

Science.gov (United States)

Horváth, Ilona Sárvári; Sjöde, Anders; Nilvebrant, Nils-Olof; Zagorodni, Andrei; Jönsson, Leif J

2004-01-01

Six anion-exchange resins with different properties were compared with respect to detoxification of a dilute-acid hydrolysate of spruce prior to ethanolic fermentation with Saccharomyces cerevisiae. The six resins encompassed strong and weak functional groups as well as styrene-, phenol-, and acrylic-based matrices. In an analytical experimental series, fractions from columns packed with the different resins were analyzed regarding pH, glucose, furfural, hydroxymethylfurfural, phenolic compounds, levulinic acid, acetic acid, formic acid, and sulfate. An initial adsorption of glucose occurred in the strong alkaline environment and led to glucose accumulation at a later stage. Acetic and levulinic acid passed through the column before formic acid, whereas sulfate had the strongest affinity. In a preparative experimental series, one fraction from each of six columns packed with the different resins was collected for assay of the fermentability and analysis of glucose, mannose, and fermentation inhibitors. The fractions collected from strong anion-exchange resins with styrene-based matrices displayed the best fermentability: a sevenfold enhancement of ethanol productivity compared with untreated hydrolysate. Fractions from a strong anion exchanger with acrylic-based matrix and a weak exchanger with phenol-based resin displayed an intermediate improvement in fermentability, a four- to fivefold increase in ethanol productivity. The fractions from two weak exchangers with styrene- and acrylic-based matrices displayed a twofold increase in ethanol productivity. Phenolic compounds were more efficiently removed by resins with styrene- and phenol-based matrices than by resins with acrylic-based matrices.

Selectivity in stripping of alkali-metal cations from crown ether carboxylate complexes

International Nuclear Information System (INIS)

Bartsch, R.A.; Walkowiak, W.; Robison, T.W.

1992-01-01

To probe the effect of structural variations within the ionophore upon the efficiency and selectivity of solvent extraction, a variety of crown ether carboxylic acids and phosphonic acid monoesters have been synthesized. In other studies the influence of the organic diluent upon extraction efficiency and selectivity has been probed for such proton-ionizable crown ethers. In the present investigation, attention is focused upon selectivity in the stripping step. Although the efficiency of metal ion stripping is often examined in solvent extraction studies, the selectivity of competitive metal ion release under different conditions is much less frequently considered. In this study, competitive stripping of metal ions from chloroform solutions of five-alkali-metal crown ether carboxylates by varying concentrations of aqueous hydrochloric acid is examined. Alkali metals used were Li, Na, K, Rb, and Cs

Converting Eucalyptus biomass into ethanol: Financial and sensitivity analysis in a co-current dilute acid process. Part II

International Nuclear Information System (INIS)

Gonzalez, R.; Treasure, T.; Phillips, R.; Jameel, H.; Saloni, D.; Wright, J.; Abt, R.

2011-01-01

The technical and financial performance of high yield Eucalyptus biomass in a co-current dilute acid pretreatment followed by enzymatic hydrolysis process was simulated using WinGEMS registered and Excel registered . Average ethanol yield per dry Mg of Eucalyptus biomass was approximately 347.6 L of ethanol (with average carbohydrate content in the biomass around 66.1%) at a cost of 0.49 L -1 of ethanol, cash cost of ∝0.46 L -1 and CAPEX of 1.03 L -1 of ethanol. The main cost drivers are: biomass, enzyme, tax, fuel (gasoline), depreciation and labor. Profitability of the process is very sensitive to biomass cost, carbohydrate content (%) in biomass and enzyme cost. Biomass delivered cost was simulated and financially evaluated in Part I; here in Part II the conversion of this raw material into cellulosic ethanol using the dilute acid process is evaluated. (author)

An overview the boron dilution issue in PWRs

International Nuclear Information System (INIS)

Hyvaerinen, J.

1994-01-01

The presentation is an overview of boron (boric acid) dilution in pressurized water reactors (PWRs). Boric acid has been widely used in PWRs as a dissolved poison, as one of the main reactivity controlling means, for a long time, from nearly but not quite from the beginning of the design, construction and operation of PWRs in the present-day sense. The specific safety issue, namely the risk of uncontrolled reactivity insertion due to inadvertent boron dilution, is discussed first, followed by a brief look on the history of boron usage in PWRs. A discussion of boron dilution phenomenology is presented next in general terms. Some particular concerns that boron dilution phenomena arouse in the minds of a regulator will also be presented before concluding with a brief look on the future of dissolved poisons. (11 refs.)

Thermochemistry of uranium(VI), arsenic, and alkali metal triple oxides

International Nuclear Information System (INIS)

Karyakin, N.V.; Chernorukov, G.N.

1994-01-01

The standard enthalpies of reactions of stoichiometric mixtures of potassium dyhydrogen orthoarsenate, uranium(VI) oxide, alkali metal nitrates, and of mixtures of triple oxides with the general formula M I AsUO 6 (M I =Li, Na, K, Rb, and Cs) and potassium nitrate with aqueous solution of hydrofluoric acid were determined an an adiabatic calorimeter at 298.15 K. The standard enthalpies of formation of uranium(VI), arsenic, and alkali metal triple oxides at 298.15 K were calculated form the data obtained. 8 refs., 1 tab

Comparison of arsenic acid with phosphoric acid in the interaction with a water molecule and an alkali/alkaline-earth metal cation.

Science.gov (United States)

Park, Sung Woo; Kim, Chang Woo; Lee, Ji Hyun; Shim, Giwoong; Kim, Kwang S

2011-10-20

Recently, Wolfe-Simon has discovered a bacterium which is able to survive using arsenic(V) rather than phosphorus(V) in its DNA. Thus it is important to investigate some important structural and chemical similarities and dissimilarities between phosphate and arsenate. We compared the monohydrated structures and the alkali/alkaline-earth metal (Na(+), K(+), Mg(2+) and Ca(2+)) complexes of the arsenic acid/anions with those of the phosphoric acid/anions [i.e., H(m)PO(4)(-(3-m)) vs H(m)AsO(4)(-(3-m)) (m = 1-3)]. We carried out geometry optimization along with harmonic frequency calculations using ab initio calculations. Despite the increased van der Waals radius of As, the hydrated structures of both P and As systems show very close similarity (within 0.25 Å in the P/As···O(water) distance and within a few kJ/mol in binding energy) because of the increased induction energies by more polar arsenic acid/anons and slightly increased dispersion energy by a larger size of the As atom. In the metal complexes, the arsenic acid has a slightly larger binding distance (by 0.07-1.0 Å) and weaker binding energy because the As(V) ion has a slightly larger radius than the P(V) ion, and the electrostatic interaction is the dominating feature in these systems.

Application of chemical methods to assess the mechanism of alkali activation in low calcium fly ash

Energy Technology Data Exchange (ETDEWEB)

Arjunan, P.; Silsbee, M.R.; Roy, D.M. [Pennsylvania State Univ., PA (United States). Materials Research Lab.

1999-11-01

A better understanding of the amount of fly ash unreacted remaining after alkali activation of low calcium fly ash is necessary for elucidating the underlying alkali activation mechanism. An approach to this determination is reported in this study which utilizes an ethylenediamine tetraacetic acid/triethanolamine/NaOH mixture to determine the unreacted fly ash particles present in an OPC-low calcium fly ash mixture, with and without alkali activation. This study also uses another chemical technique called orthophosphoric acid dissolution method to assess the amount of unreacted crystalline phases present in hydrated OPC-ash mixtures at different ages of hydration. The information obtained from these two chemical techniques was used to identify the nature of unreacted fly ash particles present in the hydrated samples. The amount of unreacted fly ash and the compressive strength data were correlated to assess the extent of influence of alkali activation on the reactivity of the amorphous and crystalline phase content of the low calcium fly ash.

Combined alkali and acid pretreatment of spent mushroom substrate for reducing sugar and biofertilizer production.

Science.gov (United States)

Zhu, Hong-Ji; Liu, Jia-Heng; Sun, Li-Fan; Hu, Zong-Fu; Qiao, Jian-Jun

2013-05-01

Spent mushroom substrate (SMS) was pretreated with alkaline reagents including potassium hydroxide, lime and ammonia to enhance enzymatic saccharification. Under the best pretreatment conditions (1M KOH, 80 °C, 90 min; 1M lime, 80 °C, 120 min; 10 M ammonia, 70 °C, 120 min), the total reducing sugar (TRS) yield reached 258.6, 204.2 and 251.2 mg/g raw SMS, which were respectively 6.15, 4.86, and 5.98 times of untreated SMS. The effects of pretreatment by above alkaline reagents and sulfuric acid on the composition and structure of SMS were evaluated to provide comparative performance data. A new process, combined alkali and acid (CAA) pretreatment followed by enzymatic hydrolysis, was innovatively proposed to improve the cost-effectiveness and avoid environmental problems. The SMS residue after CAA pretreatment-enzymatic hydrolysis process was converted to biofertilizer with Pichia farinose FL7 and a cell density of 3.0×10(8) cfu/g in biomass was attained. Copyright © 2013 Elsevier Ltd. All rights reserved.

Alkali metal and alkali earth metal gadolinium halide scintillators

Science.gov (United States)

Bourret-Courchesne, Edith; Derenzo, Stephen E.; Parms, Shameka; Porter-Chapman, Yetta D.; Wiggins, Latoria K.

2016-08-02

The present invention provides for a composition comprising an inorganic scintillator comprising a gadolinium halide, optionally cerium-doped, having the formula A.sub.nGdX.sub.m:Ce; wherein A is nothing, an alkali metal, such as Li or Na, or an alkali earth metal, such as Ba; X is F, Br, Cl, or I; n is an integer from 1 to 2; m is an integer from 4 to 7; and the molar percent of cerium is 0% to 100%. The gadolinium halides or alkali earth metal gadolinium halides are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

Milk-alkali syndrome

Science.gov (United States)

Calcium-alkali syndrome; Cope syndrome; Burnett syndrome; Hypercalcemia; Calcium metabolism disorder ... Milk-alkali syndrome is almost always caused by taking too many calcium supplements, usually in the form of calcium carbonate. Calcium ...

Effectiveness of Alkali and Acid to Produce Collagen from Fish Skin of Striped Catifish

Directory of Open Access Journals (Sweden)

Hilda Lu’lu’in Nanda Alfira Devi

2017-08-01

Full Text Available Fish skin is one of the alternative sources contained high protein  to isolate collagen. Fish skin generally extracted by the method of acid, alkali and enzymes. The study aim to determine the effectiveness of NaOHand acetic acid on catfish (Pangasius sp. skin extraction  process.  The concentrations of alkaline pretreatment were 0,05; 0,1; 0,15 and 0,2 M with the soaking time of 2, 4, 6, 8 and 10 h by NaOH replacement in every 2 h. The concentrations of acetic acid for hydrolisis process were 0.05; 0.1; 0.15 and 0.2 M with the soaking time of 1, 2, and 3 h. The experimental design used for pretreatment process is split splot, while for the hydrolysis process is factorial completely randomized design. The results showed that pretreatment with a concentration of 0.05 M NaOH for 4 h has a significant effect for eliminating non-collagen protein (p<0.05. The acetic acid concentration of 0.15 M for 1 h also has a significant effect on fish skin swelling. The yield of striped catfish collagen was 17.272%, the protein content was 86%, and the viscosity was 12 cP. Fish skin extract was identified as type I collagen by functional groups and electrophoretic analysis. Collagen from striped catfish skin has α1 and α2 and protein structure with the molecular weight of α chain were 94 and 98 kDa, meanwhile the molecular wheight of β chain was 204 kD.

Liquid alkali metals and alkali-based alloys as electron-ion plasmas

International Nuclear Information System (INIS)

Tosi, M.P.

1981-06-01

The article reviews the theory of thermodynamic and structural properties of liquid alkali metals and alkali-based alloys, within the framework of linear screening theory for the electron-ion interactions. (author)

Impact of Alkali Source on Vitrification of SRS High Level Waste

International Nuclear Information System (INIS)

LAMBERT, D. P.; MILLER, D. H.; PEELER, D. K.; SMITH, M. E.; STONE, M. E.

2005-01-01

The Defense Waste Processing Facility (DWPF) Savannah River Site is currently immobilizing high level nuclear waste sludge by vitrification in borosilicate glass. The processing strategy involves blending a large batch of sludge into a feed tank, washing the sludge to reduce the amount of soluble species, then processing the large ''sludge batch'' through the DWPF. Each sludge batch is tested by the Savannah River National Laboratory (SRNL) using simulants and tests with samples of the radioactive waste to ''qualify'' the batch prior to processing in the DWPF. The DWPF pretreats the sludge by first acidifying the sludge with nitric and formic acid. The ratio of nitric to formic acid is adjusted as required to target a final glass composition that is slightly reducing (the target is for ∼20% of the iron to have a valence of two in the glass). The formic acid reduces the mercury in the feed to elemental mercury which is steam stripped from the feed. After a concentration step, the glass former (glass frit) is added as a 50 wt% slurry and the batch is concentrated to approximately 50 wt% solids. The feed slurry is then fed to a joule heated melter maintained at 1150 C. The glass must meet both processing (e.g., viscosity and liquidus temperature) and product performance (e.g., durability) constraints The alkali content of the final waste glass is a critical parameter that affects key glass properties (such as durability) as well as the processing characteristics of the waste sludge during the pretreatment and vitrification processes. Increasing the alkali content of the glass has been shown to improve the production rate of the DWPF, but the total alkali in the final glass is limited by constraints on glass durability and viscosity. Two sources of alkali contribute to the final alkali content of the glass: sodium salts in the waste supernate and sodium and lithium oxides in the glass frit added during pretreatment processes. Sodium salts in the waste supernate can

Application of a continuous twin screw-driven process for dilute acid pretreatment of rape straw.

Science.gov (United States)

Choi, Chang Ho; Oh, Kyeong Keun

2012-04-01

Rape straw, a processing residue generated from the bio-oil industry, was used as a model biomass for application of continuous twin screw-driven dilute acid pretreatment. The screw rotation speed and feeding rate were adjusted to 19.7rpm and 0.5g/min, respectively to maintain a residence time of 7.2min in the reaction zone, respectively. The sulfuric acid concentration was 3.5wt% and the reaction temperature was 165°C. The enzymatic digestibility of the glucan in the pretreated solids was 70.9%. The continuous process routinely gave around 28.8% higher yield for glucan digestibility than did the batch processing method. Copyright © 2012 Elsevier Ltd. All rights reserved.

Reaction of acid esters of methylenebis(phosphonous acid) with carbonyl compounds

International Nuclear Information System (INIS)

Novikova, Z.S.; Odinets, I.L.; Lutsenko, I.F.

1987-01-01

The reaction of methylenebis(phosphonites) containing two hydrophosphoryl groupings with aliphatic and aromatic aldehydes and ketones in the presence of alkali metal fluorides leads to methylenebis(α-hydroxyalkylphosphinates). The reaction of methylenebis(phosphonites) containing one hydrophosphoryl groupings with carbonyl compounds in the presence of alkali metal fluorides proceeds with the formation of a new type of heterocyclic phosphorus compound, viz., 1,2λ 3 ,4λ 5 -oxadiphospholanes. The reaction of acid esters of methylenebis(phosphonous) acid with carbonyl compounds in the presence of alkali metal alkoxides or a tertiary amine is accompanied by phosphinate-phosphonate rearrangement of the intermediately formed α-hydroxylalkylphosphinates

Methods of recovering alkali metals

Science.gov (United States)

Krumhansl, James L; Rigali, Mark J

2014-03-04

Approaches for alkali metal extraction, sequestration and recovery are described. For example, a method of recovering alkali metals includes providing a CST or CST-like (e.g., small pore zeolite) material. The alkali metal species is scavenged from the liquid mixture by the CST or CST-like material. The alkali metal species is extracted from the CST or CST-like material.

Alkali-vapor laser-excimer pumped alkali laser

International Nuclear Information System (INIS)

Yue Desheng; Li Wenyu; Wang Hongyan; Yang Zining; Xu Xiaojun

2012-01-01

Based on the research internal and overseas, the principle of the excimer pumped alkali laser (XPAL) is explained, and the advantages and disadvantages of the XPAL are analyzed. Taking into consideration the difficulties that the diode pumped alkali laser (DPAL) meets on its development, the ability to solve or avoid these difficulties of XPAL is also analyzed. By summing up the achievements of the XPAL, the possible further prospect is proposed. The XPAL is of possibility to improve the performance of the DPAL. (authors)

Molybdenum/alkali metal/ethylene glycol complexes useful as epoxidation catalysts

International Nuclear Information System (INIS)

Marquis, E.T.; Sanderson, J.R.; Keating, K.P.

1987-01-01

This patent describes a clear, storage stable solution of a molybdenum/alkali metal/ethylene glycol complex in ethylene glycol made by the process comprising: reacting at an elevated temperature between about 25 0 and 150 0 C a solid ammonium molybdate or a hydrate thereof and a solid alkali metal molybdate or a hydrate thereof with ethylene glycol, such that the ratio of moles of ethylene glycol to total gram atoms of molybdenum in the molybdates ranges from about 7:10 to 10:1, and the ratio of gram atoms of molybdenum in the ammonium molybdate or hydrate thereof to gram atoms of molybdenum in the alkali metal molybdate is from about 1:1 to about 20:1 to thereby provide a reaction product composed of a solution of an alkali metal-containing complex of molybdenum, alkali metal and ethylene glycol and by-products, including water, in the ethylene glycol and subsequently stripping the solution at a reduced pressure to remove from about 5 to about 25% of the reaction product, as distillate, to thereby provide a storage stable solution of the complex in the ethylene glycol having a molybdenum content of about 6 wt. % to about 20 wt. %, a water concentration of about 0.1 wt. % to about 6 wt. % and an acid number of more than about 60

Alkali metal ion battery with bimetallic electrode

Science.gov (United States)

Boysen, Dane A; Bradwell, David J; Jiang, Kai; Kim, Hojong; Ortiz, Luis A; Sadoway, Donald R; Tomaszowska, Alina A; Wei, Weifeng; Wang, Kangli

2015-04-07

Electrochemical cells having molten electrodes having an alkali metal provide receipt and delivery of power by transporting atoms of the alkali metal between electrode environments of disparate chemical potentials through an electrochemical pathway comprising a salt of the alkali metal. The chemical potential of the alkali metal is decreased when combined with one or more non-alkali metals, thus producing a voltage between an electrode comprising the molten the alkali metal and the electrode comprising the combined alkali/non-alkali metals.

Dairy Manure as a Potential Feedstock for Cost-Effective Cellulosic Bioethanol

Directory of Open Access Journals (Sweden)

Qiang Yang

2015-12-01

Full Text Available This study investigated sulfite pretreatment to overcome recalcitrance of lignocelluloses (SPORL pretreatment and subsequent enzymatic digestibility of undigested dairy manure to preliminarily assess its potential use as an inexpensive feedstock for cellulosic bioethanol production. The sulfite pretreatment was carried out in a factorial analysis using 163 to 197 °C for 3 to 37 min with 0.8% to 4.2% sulfuric acid combined with 2.6% to 9.4% sodium sulfite. These treatments were compared with other standard pretreatments of dilute acid, and hot and cold alkali pretreatments. This comparative study showed that the sulfite pretreatment, through its combined effects of hemicellulose and lignin removal and lignin sulfonation, is more effective than the diluted acid and alkali pretreatments to improve the enzymatic digestibility of dairy manure.

Studying the effect of thermal and acid exposure on alkali activated slag Geopolymer

Directory of Open Access Journals (Sweden)

Khater H.M.

2014-04-01

Full Text Available This article reports a study about thermal stability as well as acid resistance of geopolymer materials prepared from Ground Granulated Blast Furnace Slag (GGBFS, Air Cooled Slag (ACS, Silica fume (SF and cement kiln dust (CKD using 6% (weight of equal mix from alkaline sodium hydroxide and sodium silicate activators. Study of addition of ACS, SF and CKD as partial replacement of GGBFS is investigated so as to improve the mechanical and microstructural properties of geopolymer mixes. Compressive strength and SEM were utilized in these studies. Materials were prepared using water/binder of 0.30 at 38°C and 100% RH. Results showed that geopolymer materials prepared using alkali activated slag exhibit large changes in compressive strength with increasing the firing temperature from 300 to 1000°C and exhibit an enhancement in thermal stability as compared to concrete specimens. Materials prepared by replacing GGBFS by 15% ACS resist thermal deterioration up to 1000°C. It was suggested to be suitable for refractory insulation applications as well as for production of nuclear concrete reactors. On the other hand, geopolymer mixes exhibit low stability upon subjecting to different concentration from the mix of nitric and hydrochloric acid in equal ratio (1:1. Current studies of geopolymer microstructure were focused on the morphology as well as the relationship between compositions and mechanical properties.

In vivo synthesized 34S enriched amino acid standards for species specific isotope dilution of proteins

DEFF Research Database (Denmark)

Hermann, Gerrit; Moller, Laura Hyrup; Gammelgaard, Bente

2016-01-01

(ICP-MS) combined to anion exchange showed that very high concentrated spike material could be produced with [small mu ]mol amounts of proteinogenic sulfur containing amino acids per g cell dry weight. An enrichment of 34S to 96.3 +/- 0.4% (n = 3) and 98.5 +/- 0.4% (n = 3) for cysteic acid...... with the concept of species specific isotope dilution analysis (IDA). The method relies on the determination of the two sulfur containing amino acids, cysteine and methionine by sulfur speciation analysis and is hence applicable to any protein containing sulfur. In vivo synthesis using 34S as sulfur source...... and methionine sulfone, respectively, was assessed. The established IDA method was validated for the absolute quantification of commercially available lysozyme and ceruloplasmin standards including the calculation of a total combined uncertainty budget....

Evaluation of continuous ethanol fermentation of dilute-acid corn stover hydrolysate using thermophilic anaerobic bacterium Thermoanaerobacter BG1L1

DEFF Research Database (Denmark)

Georgieva, Tania I.; Ahring, Birgitte Kiær

2007-01-01

Dilute sulfuric acid pretreated corn stover is potential feedstock of industrial interest for second generation fuel ethanol production. However, the toxicity of corn stover hydrolysate (PCS) has been a challenge for fermentation by recombinant xylose fermenting organisms. In this work...

Alkali-based pretreatments distinctively extract lignin and pectin for enhancing biomass saccharification by altering cellulose features in sugar-rich Jerusalem artichoke stem.

Science.gov (United States)

Li, Meng; Wang, Jun; Yang, Yuezhou; Xie, Guanghui

2016-05-01

Jerusalem artichoke (JA) has been known as a potential nonfood feedstock for biofuels. Based on systems analysis of total 59 accessions, both soluble sugar and ash could positively affect biomass digestibility after dilute sodium hydroxide pretreatment (A). In this study, one representative accession (HEN-3) was used to illustrate its enzymatic digestibility with pretreatments of ultrasonic-assisted dilute sodium hydroxide (B), alkaline peroxide (C), and ultrasonic-assisted alkaline peroxide (D). Pretreatment D exhibited the highest hexose release rate (79.4%) and total sugar yield (10.4 g/L), which were 2.4 and 2.6 times higher, respectively, than those of the control. The analysis of cellulose crystalline index (CrI), cellulose degree of polymerization (DP), thermal behavior and SEM suggested that alkali-based pretreatments could distinctively extract lignin and pectin polymers, leading to significant alterations of cellulose CrI and DP for high biomass saccharification. Additionally, hydrogen peroxide (H2O2) could significant reduce the generation of fermentation inhibitors during alkali-based pretreatments. Copyright © 2016 Elsevier Ltd. All rights reserved.

A whole cell biocatalyst for cellulosic ethanol production from dilute acid-pretreated corn stover hydrolyzates

Energy Technology Data Exchange (ETDEWEB)

Ryu, Seunghyun; Karim, Muhammad Nazmul [Texas Tech Univ., Lubbock, TX (United States). Dept. of Chemical Engineering

2011-08-15

In this research, a recombinant whole cell biocatalyst was developed by expressing three cellulases from Clostridium cellulolyticum - endoglucanase (Cel5A), exoglucanase (Cel9E), and {beta}-glucosidase - on the surface of the Escherichia coli LY01. The modified strain is identified as LY01/pRE1H-AEB. The cellulases were displayed on the surface of the cell by fusing with an anchor protein, PgsA. The developed whole cell biocatalyst was used for single-step ethanol fermentation using the phosphoric acid-swollen cellulose (PASC) and the dilute acid-pretreated corn stover. Ethanol production was 3.59 {+-} 0.15 g/L using 10 g/L of PASC, which corresponds to a theoretical yield of 95.4 {+-} 0.15%. Ethanol production was 0.30 {+-} 0.02 g/L when 1 g/L equivalent of glucose in the cellulosic fraction of the dilute sulfuric acid-pretreated corn stover (PCS) was fermented for 84 h. A total of 0.71 {+-} 0.12 g/L ethanol was produced in 48 h when the PCS was fermented in the simultaneous saccharification and co-fermentation mode using the hemicellulosic (1 g/L of total soluble sugar) and as well as the cellulosic (1 g/L of glucose equivalent) parts of PCS. In a control experiment, 0.48 g/L ethanol was obtained from 1 g/L of hemicellulosic PCS. It was concluded that the whole cell biocatalyst could convert both cellulosic and hemicellulosic substrates into ethanol in a single reactor. The developed C. cellulolyticum-E. coli whole cell biocatalyst also overcame the incompatible temperature problem of the frequently reported fungal-yeast systems. (orig.)

Alkali resistant optical coatings for alkali lasers and methods of production thereof

Science.gov (United States)

Soules, Thomas F; Beach, Raymond J; Mitchell, Scott C

2014-11-18

In one embodiment, a multilayer dielectric coating for use in an alkali laser includes two or more alternating layers of high and low refractive index materials, wherein an innermost layer includes a thicker, >500 nm, and dense, >97% of theoretical, layer of at least one of: alumina, zirconia, and hafnia for protecting subsequent layers of the two or more alternating layers of high and low index dielectric materials from alkali attack. In another embodiment, a method for forming an alkali resistant coating includes forming a first oxide material above a substrate and forming a second oxide material above the first oxide material to form a multilayer dielectric coating, wherein the second oxide material is on a side of the multilayer dielectric coating for contacting an alkali.

Alkali metal and alkali metal hydroxide intercalates of the layered transition metal disulfides

International Nuclear Information System (INIS)

Kanzaki, Y.; Konuma, M.; Matsumoto, O.

1981-01-01

The intercalation reaction of some layered transition metal disulfides with alkali metals, alkali metal hydroxides, and tetraalkylammonium hydroxides were investigated. The alkali metal intercalates were prepared in the respective metal-hexamethylphosphoric triamide solutions in vaccuo, and the hydroxide intercalates in aqueous hydroxide solutions. According to the intercalation reaction, the c-lattice parameter was increased, and the increase indicated the expansion of the interlayer distance. In the case of alkali metal intercalates, the expansion of the interlayer distance increased continuously, corresponding to the atomic radius of the alkali metal. On the other hand, the hydroxide intercalates showed discrete expansion corresponding to the effective ionic radius of the intercalated cation. All intercalates of TaS 2 amd NbS 2 were superconductors. The expansion of the interlayer distance tended to increase the superconducting transition temperature in the intercalates of TaS 2 and vice versa in those of NbS 2 . (orig.)

Alteration of alkali reactive aggregates autoclaved in different alkali solutions and application to alkali-aggregate reaction in concrete (II) expansion and microstructure of concrete microbar

International Nuclear Information System (INIS)

Lu Duyou; Mei Laibao; Xu Zhongzi; Tang Mingshu; Mo Xiangyin; Fournier, Benoit

2006-01-01

The effect of the type of alkalis on the expansion behavior of concrete microbars containing typical aggregate with alkali-silica reactivity and alkali-carbonate reactivity was studied. The results verified that: (1) at the same molar concentration, sodium has the strongest contribution to expansion due to both ASR and ACR, followed by potassium and lithium; (2) sufficient LiOH can completely suppress expansion due to ASR whereas it can induce expansion due to ACR. It is possible to use the duplex effect of LiOH on ASR and ACR to clarify the ACR contribution when ASR and ACR may coexist. It has been shown that a small amount of dolomite in the fine-grained siliceous Spratt limestone, which has always been used as a reference aggregate for high alkali-silica reactivity, might dedolomitize in alkaline environment and contribute to the expansion. That is to say, Spratt limestone may exhibit both alkali-silica and alkali-carbonate reactivity, although alkali-silica reactivity is predominant. Microstructural study suggested that the mechanism in which lithium controls ASR expansion is mainly due to the favorable formation of lithium-containing less-expansive product around aggregate particles and the protection of the reactive aggregate from further attack by alkalis by the lithium-containing product layer

ALKALI FUSION OF ROSETTA ZIRCON

International Nuclear Information System (INIS)

DAHER, A.

2008-01-01

The decomposition of Rosetta zircon by fusion with different types of alkalis has been investigated. These alkalis include sodium hydroxide, potassium hydroxide and eutectic mixture of both. The influences of the reaction temperature, zircon to alkalis ratio, fusion time and the stirring of the reactant on the fusion reaction have been evaluated. The obtained results favour the decomposition of zircon with the eutectic alkalis mixture by a decomposition efficiency of 96% obtained at 500 0 C after one hour

Kinetic characterization for hemicellulose hydrolysis of corn stover in a dilute acid cycle spray flow-through reactor at moderate conditions

International Nuclear Information System (INIS)

Jin, Qiang; Zhang, Hongman; Yan, Lishi; Qu, Liang; Huang, He

2011-01-01

The kinetic characterization of hemicellulose hydrolysis of corn stover was investigated using a new reactor of dilute acid cycle spray flow-through (DCF) pretreatment. The primary purpose was to obtain kinetic data for hemicellulose hydrolysis with sulfuric acid concentrations (10-30 kg m -3 ) at relatively low temperatures (90-100 o C). A simplified kinetic model was used to describe its performance at moderate conditions. The results indicate that the rates of xylose formation and degradation are sensitive to flow rate, temperature and acid concentration. Moreover, the kinetic data of hemicellulose hydrolysis fit a first-order reaction model and the experimental data with actual acid concentration after accounting for the neutralization effect of the substrates at different temperatures. Over 90% of the xylose monomer yield and below 5.5% of degradation product (furfural) yield were observed in this reactor. Kinetic constants for hemicellulose hydrolysis models were analyzed by an Arrhenius-type equation, and the activation energy of xylose formation were 111.6 kJ mol -1 , and 95.7 kJ mol -1 for xylose degradation, respectively. -- Highlights: → Investigating a novel pretreatment reactor of dilute acid cycle spray flow-through. → Xylose yield is sensitive to flow rate, temperature and acid concentration. → Obtaining relatively higher xylose monomer yield and lower fermentation inhibitor. → Lumping hemicellulose and xylan oligmers together in the model is a valid way. → The kinetic model as a guide for reactor design, and operation strategy optimization.

Mild-temperature dilute acid pretreatment for integration of first and second generation ethanol processes.

Science.gov (United States)

Nair, Ramkumar B; Kalif, Mahdi; Ferreira, Jorge A; Taherzadeh, Mohammad J; Lennartsson, Patrik R

2017-12-01

The use of hot-water (100°C) from the 1st generation ethanol plants for mild-temperature lignocellulose pretreatment can possibly cut down the operational (energy) cost of 2nd generation ethanol process, in an integrated model. Dilute-sulfuric and -phosphoric acid pretreatment at 100°C was carried out for wheat bran and whole-stillage fibers. Pretreatment time and acid type influenced the release of sugars from wheat bran, while acid-concentration was found significant for whole-stillage fibers. Pretreatment led up-to 300% improvement in the glucose yield compared to only-enzymatically treated substrates. The pretreated substrates were 191-344% and 115-300% richer in lignin and glucan, respectively. Fermentation using Neurospora intermedia, showed 81% and 91% ethanol yields from wheat bran and stillage-fibers, respectively. Sawdust proved to be a highly recalcitrant substrate for mild-temperature pretreatment with only 22% glucose yield. Both wheat bran and whole-stillage are potential substrates for pretreatment using waste heat from the 1st generation process for 2nd generation ethanol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Alkali metal for ultraviolet band-pass filter

Science.gov (United States)

Mardesich, Nick (Inventor); Fraschetti, George A. (Inventor); Mccann, Timothy A. (Inventor); Mayall, Sherwood D. (Inventor); Dunn, Donald E. (Inventor); Trauger, John T. (Inventor)

1993-01-01

An alkali metal filter having a layer of metallic bismuth deposited onto the alkali metal is provided. The metallic bismuth acts to stabilize the surface of the alkali metal to prevent substantial surface migration from occurring on the alkali metal, which may degrade optical characteristics of the filter. To this end, a layer of metallic bismuth is deposited by vapor deposition over the alkali metal to a depth of approximately 5 to 10 A. A complete alkali metal filter is described along with a method for fabricating the alkali metal filter.

Impact of recycling stillage on conversion of dilute sulfuric acid pretreated corn stover to ethanol.

Science.gov (United States)

Mohagheghi, Ali; Schell, Daniel J

2010-04-01

Both the current corn starch to ethanol industry and the emerging lignocellulosic biofuels industry view recycling of spent fermentation broth or stillage as a method to reduce fresh water use. The objective of this study was to understand the impact of recycling stillage on conversion of corn stover to ethanol. Sugars in a dilute-acid pretreated corn stover hydrolysate were fermented to ethanol by the glucose-xylose fermenting bacteria Zymomonas mobilis 8b. Three serial fermentations were performed at two different initial sugar concentrations using either 10% or 25% of the stillage as makeup water for the next fermentation in the series. Serial fermentations were performed to achieve near steady state concentration of inhibitors and other compounds in the corn stover hydrolysate. Little impact on ethanol yields was seen at sugar concentrations equivalent to pretreated corn stover slurry at 15% (w/w) with 10% recycle of the stillage. However, ethanol yields became progressively poorer as the sugar concentration increased and fraction of the stillage recycled increased. At an equivalent corn stover slurry concentration of 20% with 25% recycled stillage the ethanol yield was only 5%. For this microorganism with dilute-acid pretreated corn stover, recycling a large fraction of the stillage had a significant negative impact on fermentation performance. Although this finding is of concern for biochemical-based lignocellulose conversion processes, other microorganism/pretreatment technology combinations will likely perform differently. (c) 2009 Wiley Periodicals, Inc.

pH effect on the enthalpy of dilution and volumetric properties of protocatechuic acid at T = 298.15 K

International Nuclear Information System (INIS)

Zheng, Yan; Liu, Min; Wang, Yong; Wang, Chunmei; Sun, Dezhi; Wang, Bingquan

2014-01-01

Graphical abstract: The dilution thermal power of PCA in potassium phosphate buffer solutions at different pHs and apparent molar volumes were determined in order to investigate the interactions of PCA with the coexistent spicies. - Highlights: • Enthalpies of dilution and apparent molar volumes of PCA in PBS at different pHs were measured. • Enthalpic interaction coefficients, limiting partial molar volumes and experimental slopes of PCA were determined. • The pH dependence of the weak interactions in the investigated system was obtained. • (Solute + solvent) interactions and structure making/breaking ability of solutes in the given system were discussed. - Abstract: The enthalpies of dilution of protocatechuic acid, a natural anti-cancer substance, in sodium phosphate and potassium phosphate buffer solutions with different pH values were measured by using a mixing-flow microcalorimeter at T = 298.15 K. Densities of the pseudo binary system (phosphate buffer + protocatechuic acid) were also measured with a quartz vibrating-tube densimeter. The enthalpic interaction coefficients (h 2 , h 3 and h 4 ) were computed according to the McMillan–Mayer model. Apparent molar volumes of the system were calculated from the data of densities, which have been used to deduce limiting partial molar volumes (V ϕ 0 ) of protocatechuic acid at different pH values. The aim of the experiments and data process is to investigate the interaction between the molecules of the important drug and that of the drug molecule with coexistent species in aqueous solutions as well as the influences on these interactions of such factors as pH and ion strength. Change trends of the enthalpic pair wise interaction coefficient h 2 and V ϕ 0 of protocatechuic acid with pH increasing in the both phosphate buffer solutions were obtained. The thermodynamic properties, h 2 and V ϕ 0 in potassium phosphate buffer solutions were compared with those in sodium phosphate buffer solutions at

Dilution Confusion: Conventions for Defining a Dilution

Science.gov (United States)

Fishel, Laurence A.

2010-01-01

Two conventions for preparing dilutions are used in clinical laboratories. The first convention defines an "a:b" dilution as "a" volumes of solution A plus "b" volumes of solution B. The second convention defines an "a:b" dilution as "a" volumes of solution A diluted into a final volume of "b". Use of the incorrect dilution convention could affect…

Comparing oxidative and dilute acid wet explosion pretreatment of Cocksfoot grass at high dry matter concentration for cellulosic ethanol production

DEFF Research Database (Denmark)

Njoku, Stephen Ikechukwu; Uellendahl, Hinrich; Ahring, Birgitte Kiær

2013-01-01

into cellulose monomeric C6 sugars was achieved for WEx condition AC-E (180°C, 15 min, and 0.2% sulfuric acid). For that condition, the highest ethanol yield of 197 g/kg DM (97% of theoretical maximum value) was achieved for SSF process by Saccharomyces cerevisiae. However, the highest concentration...... of hemicellulose C5 sugars was found for WEx pretreatment condition O2-A (160°C, 15 min, and 6 bar O2) which means that the highest potential ethanol yield was found at this moderate pretreatment condition with oxygen added. Increasing the pretreatment temperature to 180–190°C with addition of oxygen or dilute...... was investigated for cellulosic ethanol production. The biomass raw materials were pretreated using wet explosion (WEx) at 25% dry matter concentration with addition of oxygen or dilute sulfuric acid. The enzymatic hydrolysis of cellulose was significantly improved after pretreatment. The highest conversion...

Selection of suitable mineral acid and its concentration for biphasic dilute acid hydrolysis of the sodium dithionite delignified Prosopis juliflora to hydrolyze maximum holocellulose.

Science.gov (United States)

Naseeruddin, Shaik; Desai, Suseelendra; Venkateswar Rao, L

2016-02-01

Two grams of delignified substrate at 10% (w/v) level was subjected to biphasic dilute acid hydrolysis using phosphoric acid, hydrochloric acid and sulfuric acid separately at 110 °C for 10 min in phase-I and 121 °C for 15 min in phase-II. Combinations of acid concentrations in two phases were varied for maximum holocellulose hydrolysis with release of fewer inhibitors, to select the suitable acid and its concentration. Among three acids, sulfuric acid in combination of 1 & 2% (v/v) hydrolyzed maximum holocellulose of 25.44±0.44% releasing 0.51±0.02 g/L of phenolics and 0.12±0.002 g/L of furans, respectively. Further, hydrolysis of delignified substrate using selected acid by varying reaction time and temperature hydrolyzed 55.58±1.78% of holocellulose releasing 2.11±0.07 g/L and 1.37±0.03 g/L of phenolics and furans, respectively at conditions of 110 °C for 45 min in phase-I & 121 °C for 60 min in phase-II. Copyright © 2015 Elsevier Ltd. All rights reserved.

Alkali metal hydride formation

International Nuclear Information System (INIS)

1976-01-01

The present invention relates to a method of producing alkali metal hydrides by absorbing hydrogen gas under pressure into a mixture of lower alkyl mono amines and alkali metal alkyl amides selected from sodium and potassium amides formed from said amines. The present invention also includes purification of a mixture of the amines and amides which contain impurities, such as is used as a catalytic exchange liquid in the enrichment of deuterium, involving the formation of the alkali metal hydride

Rapid and Precise Measurement of Serum Branched-Chain and Aromatic Amino Acids by Isotope Dilution Liquid Chromatography Tandem Mass Spectrometry

OpenAIRE

Yang, Ruiyue; Dong, Jun; Guo, Hanbang; Li, Hongxia; Wang, Shu; Zhao, Haijian; Zhou, Weiyan; Yu, Songlin; Wang, Mo; Chen, Wenxiang

2013-01-01

BACKGROUND: Serum branched-chain and aromatic amino acids (BCAAs and AAAs) have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming. METHODS: An isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method for serum BCAAs and AAAs was developed. The serum was mixed with isotope-labeled BCAA and AAA internal standar...

Process for the disposal of alkali metals

International Nuclear Information System (INIS)

Lewis, L.C.

1979-01-01

The invention describes a method of disposing of alkali metals by forming a solid waste for storage. The method comprises preparing an aqueous disposal solution of at least 55 weight percent alkali metal hydroxide, heating the alkali metal to melting temperature to form a feed solution, and spraying the molten feed solution into the disposal solution. The alkali metal reacts with the water in the disposal solution in a controlled reaction which produces alkali metal hydroxide, hydrogen and heat and thereby forms a solution of alkali metal hydroxides. Water is added to the solution in amounts sufficient to maintain the concentration of alkali metal hydroxides in the solution at 70 to 90 weight percent, and to maintain the temperature of the solution at about the boiling point. Removing and cooling the alkali metal hydroxide solution thereby forms a solid waste for storage. The method is particularly applicable to radioactive alkali metal reactor coolant. (auth)

The Effects of Various Amendments on Trace Element Stabilization in Acidic, Neutral, and Alkali Soil with Similar Pollution Index.

Science.gov (United States)

Kim, Min-Suk; Min, Hyun-Gi; Lee, Sang-Hwan; Kim, Jeong-Gyu

2016-01-01

Many studies have examined the application of soil amendments, including pH change-induced immobilizers, adsorbents, and organic materials, for soil remediation. This study evaluated the effects of various amendments on trace element stabilization and phytotoxicity, depending on the initial soil pH in acid, neutral, and alkali conditions. As in all types of soils, Fe and Ca were well stabilized on adsorption sites. There was an effect from pH control or adsorption mechanisms on the stabilization of cationic trace elements from inorganic amendments in acidic and neutral soil. Furthermore, acid mine drainage sludge has shown great potential for stabilizing most trace elements. In a phytotoxicity test, the ratio of the bioavailable fraction to the pseudo-total fraction significantly affected the uptake of trace elements by bok choy. While inorganic amendments efficiently decreased the bioavailability of trace elements, significant effects from organic amendments were not noticeable due to the short-term cultivation period. Therefore, the application of organic amendments for stabilizing trace elements in agricultural soil requires further study.

The Effects of Various Amendments on Trace Element Stabilization in Acidic, Neutral, and Alkali Soil with Similar Pollution Index.

Directory of Open Access Journals (Sweden)

Min-Suk Kim

Full Text Available Many studies have examined the application of soil amendments, including pH change-induced immobilizers, adsorbents, and organic materials, for soil remediation. This study evaluated the effects of various amendments on trace element stabilization and phytotoxicity, depending on the initial soil pH in acid, neutral, and alkali conditions. As in all types of soils, Fe and Ca were well stabilized on adsorption sites. There was an effect from pH control or adsorption mechanisms on the stabilization of cationic trace elements from inorganic amendments in acidic and neutral soil. Furthermore, acid mine drainage sludge has shown great potential for stabilizing most trace elements. In a phytotoxicity test, the ratio of the bioavailable fraction to the pseudo-total fraction significantly affected the uptake of trace elements by bok choy. While inorganic amendments efficiently decreased the bioavailability of trace elements, significant effects from organic amendments were not noticeable due to the short-term cultivation period. Therefore, the application of organic amendments for stabilizing trace elements in agricultural soil requires further study.

On-line alkali monitoring - Part 1

International Nuclear Information System (INIS)

Andersson, Christer; Ljung, P.; Woxlin, H.

1997-02-01

As a consequence of the increased knowledge of the environmental impact of combustion based heat and power generation, the use of renewable biofuels will be increased. An obstacle associated to biofuel combustion compared to other fuels is the large release of alkali. Alkali compounds in flue gases are known to cause severe operational problems. Three of the major problems are; fouling of superheating tubes (causing reduced heat transfer and possibly corrosion), agglomeration of the bed material in fluidized beds, and poisoning of SCR catalysts. Yet another alkali related problem arises when, in order to increase the electric efficiency of combustion power plants, combined-cycle technology is used. Alkali vapour present in the fuel gas for the gas turbine is condensed to particles which increase corrosion and erosion of the turbine blades. The research on ash related operational problems has to be extended in order to ensure future use of biofuels in heat and power generation. In all successful research, adequate tools are necessary. To investigate ash related problems the key issue is to be able to perform continuous alkali measurements. This pilot study has investigated the need of continuous alkali measurements, which alkali species are harmful in the different applications and also available instrumentation capable of measuring the specific alkali species. The report gives a short summary presenting alkali related operational problems. In addition a schematic overview is given, showing the alkali species that possibly can exist in various parts of the power plant. 48 refs, 13 figs, 4 tabs

A comparative evaluation of a dipicolinic acid based dilute chemical decontaminant formulation with respect to its efficacy for dissolution of iron oxides

Energy Technology Data Exchange (ETDEWEB)

Kamal Kishore; Dey, G.R.; Naik, D.B.; Moorthy, P.N. [Applied Chemistry Division, Bhabha Atomic Research Centre, Mumbai-400 085 (India)

1998-12-31

A dilute chemical decontamination formulation containing dipicolinic acid (2,6-pyridine dicarboxylic acid PDCA) and ascorbic acid (AA) has been found to be effective in dissolving magnetite, nickel ferrite and haemetite. Its main advantages arise because of (i) good solubility of the two constituents (ii) lack of absorption on the cation exchanger from acidic media during regenerative decontamination process (iii) stability to ionizing radiation and (iv) low corrosion rate for carbon steel. Dissolution rates of iron oxides in this formulation are as good as or better than in other well known formulations. (author)

Volumetric properties of ascorbic acid (vitamin C) and thiamine hydrochloride (vitamin B1) in dilute HCl and in aqueous NaCl solutions at (283.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K

International Nuclear Information System (INIS)

Ayranci, Guler; Sahin, Melike; Ayranci, Erol

2007-01-01

Apparent molar volumes and apparent molar isentropic compressibilities of ascorbic acid (vitamin C) and thiamine hydrochloride (vitamin B 1 ) were determined from accurately measured density and sound velocity data in water and in aqueous NaCl solutions at (283.15, 293.15, 298.15, 303.15, 308.15, and 313.15) K. These volume and compressibility data were extrapolated to zero concentration using suitable empirical or theoretical equations to determine the corresponding infinite dilution values. Apparent molar expansibilities at infinite dilution were determined from slopes of apparent molar volume vs. temperature plots. Ionization of both ascorbic acid and thiamine hydrochloride were suppressed using sufficiently acidic solutions. Apparent molar volumes at infinite dilution for ascorbic acid and thiamine hydrochloride were found to increase with temperature in acidic solutions and in the presence of co-solute, NaCl. Apparent molar expansibility at infinite dilution were found to be constant over the temperature range studied and were all positive, indicating the hydrophilic character of the two vitamins studied in water and in the presence of co-solute, NaCl. Apparent molar isentropic compressibilities of ascorbic acid at infinite dilution were positive in water and in the presence of co-solute, NaCl, at low molalities. Those of thiamine hydrochloride at infinitive dilution were all negative, consistent with its ionic nature. Transfer apparent molar volumes of vitamins at infinite dilution from water solutions to NaCl solutions at various temperatures were determined. The results were interpreted in terms of complex vitamin-water-co-solute (NaCl) interactions

3-D Topo Surface Visualization of Acid-Base Species Distributions: Corner Buttes, Corner Pits, Curving Ridge Crests, and Dilution Plains

Science.gov (United States)

Smith, Garon C.; Hossain, Md Mainul

2017-01-01

Species TOPOS is a free software package for generating three-dimensional (3-D) topographic surfaces ("topos") for acid-base equilibrium studies. This upgrade adds 3-D species distribution topos to earlier surfaces that showed pH and buffer capacity behavior during titration and dilution procedures. It constructs topos by plotting…

On-chip fabrication of alkali-metal vapor cells utilizing an alkali-metal source tablet

International Nuclear Information System (INIS)

Tsujimoto, K; Hirai, Y; Sugano, K; Tsuchiya, T; Tabata, O; Ban, K; Mizutani, N

2013-01-01

We describe a novel on-chip microfabrication technique for the alkali-metal vapor cell of an optically pumped atomic magnetometer (OPAM), utilizing an alkali-metal source tablet (AMST). The newly proposed AMST is a millimeter-sized piece of porous alumina whose considerable surface area holds deposited alkali-metal chloride (KCl) and barium azide (BaN 6 ), source materials that effectively produce alkali-metal vapor at less than 400 °C. Our experiments indicated that the most effective pore size of the AMST is between 60 and 170 µm. The thickness of an insulating glass spacer holding the AMST was designed to confine generated alkali metal to the interior of the vapor cell during its production, and an integrated silicon heater was designed to seal the device using a glass frit, melted at an optimum temperature range of 460–490 °C that was determined by finite element method thermal simulation. The proposed design and AMST were used to successfully fabricate a K cell that was then operated as an OPAM with a measured sensitivity of 50 pT. These results demonstrate that the proposed concept for on-chip microfabrication of alkali-metal vapor cells may lead to effective replacement of conventional glassworking approaches. (paper)

Porous alkali activated materials with slow alkali release dynamic. Role of composition

International Nuclear Information System (INIS)

Bumanis, G.; Bajare, D.

2018-01-01

Alkali activated materials (AAM) based on calcined metakaolin or illite clay together with waste by-products, such as waste glass or aluminium scrap recycling waste, were tested as value-added materials for pH stabilization in biogas technology where decrease of pH should be avoided. Porous materials with ability to slowly leach alkalis in the water media thus providing continuous control of the pH level were obtained. XRD, FTIR, SEM and titration methods were used to characterize AAM and their leaching properties. It is clear that composition of the material has an important effect on the diffusion of alkali from structure. Namely, higher Si/Al and Na/Al molar ratios may increase pore solution transfer to the leachate. The leaching rate of alkalis from the structure of AAM is high for the first few days, decreasing over time. It was possible to calculate the buffer capacity from the mixture design of AAM. [es

Purification of alkali metal nitrates

Science.gov (United States)

Fiorucci, Louis C.; Gregory, Kevin M.

1985-05-14

A process is disclosed for removing heavy metal contaminants from impure alkali metal nitrates containing them. The process comprises mixing the impure nitrates with sufficient water to form a concentrated aqueous solution of the impure nitrates, adjusting the pH of the resulting solution to within the range of between about 2 and about 7, adding sufficient reducing agent to react with heavy metal contaminants within said solution, adjusting the pH of the solution containing reducing agent to effect precipitation of heavy metal impurities and separating the solid impurities from the resulting purified aqueous solution of alkali metal nitrates. The resulting purified solution of alkali metal nitrates may be heated to evaporate water therefrom to produce purified molten alkali metal nitrate suitable for use as a heat transfer medium. If desired, the purified molten form may be granulated and cooled to form discrete solid particles of alkali metal nitrates.

The chemistry of the liquid alkali metals

International Nuclear Information System (INIS)

Addison, C.C.

1984-01-01

A study of liquid alkali metals. It encourages comparison with molecular solvents in chapter covering the nature and reactivity of dissolved species, solvation, solubility and electrical conductivity of solutions. It demonstrates lab techniques unique to liquid alkali metals. It discusses large-scale applications from storage batteries to sodium-cooled reactors and future fusion reactors, and associated technological problems. Contents: Some Basic Physical and Chemical Properties; Manipulation of the Liquids; The Chemistry of Purification Methods; Species Formed by Dissolved Elements; Solubilities and Analytical Methods; Alkali Metal Mixtures; Solvation in Liquid Metal; Reactions Between Liquid Alkali Metals and Water; Reactions of Nitrogen with Lithium and the Group II Metals in Liquid Sodium; The Formation, Dissociation and Stability of Heteronuclear Polyatomic Anions; Reactions of the Liquid Alkali Metals and Their Alloys with Simple Alipatic Hydrocarbons; Reactions of the Liquid Alkali Metals with Some Halogen Compounds; Hydrogen, Oxygen and Carbon Meters; Surface Chemistry and Wetting; Corrosion of Transition Metals by the Liquid Alkali Metals; Modern Applications of the Liquid Alkali Metals

Towards integrated biorefinery from dried distillers grains: Selective extraction of pentoses using dilute acid hydrolysis

International Nuclear Information System (INIS)

Fonseca, Dania A.; Lupitskyy, Robert; Timmons, David; Gupta, Mayank; Satyavolu, Jagannadh

2014-01-01

The abundant availability and high level of hemicellulose content make dried distillers grains (DDG) an attractive feedstock for production of pentoses (C5) and conversion of C5 to bioproducts. One target of this work was to produce a C5 extract (hydrolyzate) with high yield and purity with a low concentration of C5 degradation products. A high selectivity towards pentoses was achieved using dilute acid hydrolysis of DDG in a percolation reactor with liquid recirculation. Pretreatment of starting material using screening and ultrasonication resulted in fractional increase of the pentose yield by 42%. A 94% yield of pentoses on the DDG (280.9 g kg −1 ) was obtained. Selective extraction of individual pentoses has been achieved by using a 2-stage hydrolysis process, resulting in arabinose-rich (arabinose 81.5%) and xylose-rich (xylose 85.2%) streams. A broader impact of this work is towards an Integrated Bio-Refinery based on DDG – for production of biofuels, biochemical intermediates, and other bioproducts. - Highlights: • A process for selective extraction of pentoses from DDG was presented as a part of integrated biorefinery approach. • The selectivity for pentoses was high using dilute acid hydrolysis in a percolation reactor with liquid recirculation. • Pretreatment of DDG using screening and ultrasonication resulted in fractional increase of the pentose yield by 42 %. • A 94% yield in pentoses (280.9 g kg −1 of DDG) was obtained. • A 2-stage hydrolysis process, developed to extract individual pentoses, resulted in arabinose and xylose rich streams

Formic acid hydrolysis/liquid chromatography isotope dilution mass spectrometry: An accurate method for large DNA quantification.

Science.gov (United States)

Shibayama, Sachie; Fujii, Shin-Ichiro; Inagaki, Kazumi; Yamazaki, Taichi; Takatsu, Akiko

2016-10-14

Liquid chromatography-isotope dilution mass spectrometry (LC-IDMS) with formic acid hydrolysis was established for the accurate quantification of λDNA. The over-decomposition of nucleobases in formic acid hydrolysis was restricted by optimizing the reaction temperature and the reaction time, and accurately corrected by using deoxynucleotides (dNMPs) and isotope-labeled dNMPs as the calibrator and the internal standard, respectively. The present method could quantify λDNA with an expanded uncertainty of 4.6% using 10fmol of λDNA. The analytical results obtained with the present method were validated by comparing with the results of phosphate-base quantification by inductively coupled plasma-mass spectrometry (ICP-MS). The results showed good agreement with each other. We conclude that the formic acid hydrolysis/LC-IDMS method can quantify λDNA accurately and is promising as the primary method for the certification of DNA as reference material. Copyright © 2016 Elsevier B.V. All rights reserved.

Saturated vapor pressure over molten mixtures of GaCl{sub 3} and alkali metal chlorides; Davlenie nasyshchennykh parov rasplavlennykh smesej CaCl{sub 3} s khloridami shchelochnykh metallov

Energy Technology Data Exchange (ETDEWEB)

Salyulev, A B; Smolenskij, V V; Moskalenko, N I [UrO RAN, Inst. Vysokotemperaturnoj Ehlektrokhimii, Elaterinburg (Russian Federation)

2004-07-01

Volatilities of GaCl{sub 3} and alkali metal chlorides over diluted (up to 3 mol %) solutions of GaCl{sub 3} in LiCl, NaCl, KCl, RbCl, and CsCl were measured at 1100 K by dynamic and indirect static methods. Chemical composition of saturated vapor over the mixed melts was determined. Partial pressures of the components were calculated. Their values depend essentially on specific alkali metal cation and on concentration of GaCl{sub 3}; their variation permits altering parameters of GaCl{sub 3} distillation from the salt melt in a wide range.

Alkali metal hafnium oxide scintillators

Science.gov (United States)

Bourret-Courchesne, Edith; Derenzo, Stephen E.; Taylor, Scott Edward

2018-05-08

The present invention provides for a composition comprising an inorganic scintillator comprising an alkali metal hafnate, optionally cerium-doped, having the formula A2HfO3:Ce; wherein A is an alkali metal having a valence of 1, such as Li or Na; and the molar percent of cerium is 0% to 100%. The alkali metal hafnate are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

Effect of alkali-earth ions on local structure of the LaAlO3-La0.67A0.33MnO3 (A = Ca, Sr, Ba) diluted solid solutions: 27Al NMR studies

International Nuclear Information System (INIS)

Charnaya, E.V.; Cheng Tien; Lee, M.K.; Sun, S.Y.; Chejina, N.V.

2007-01-01

27 Al Magic Angle Spinning (MAS) NMR studies are carried out for diluted alkali-earth metal doped lanthanum manganite solid solutions in the lanthanum aluminate (1-y)LaAlO 3 -yLa 0.67 A 0.33 MnO 3 (A = Ca, Sr, Ba) with y = 0, 2, 3, and 5 mol %. The spectra depend on the dopant species and show higher substitutional ordering for the Ba containing mixed crystals. Magnetically shifted lines are observed in all solid solutions and attributed to Al in the octahedral oxygen environment near manganese trivalent ions. Nonlinear dependences of their intensity are referred to the manganese-rich cluster formation. An additional MAS NMR line corresponding to aluminium at sites different from the octahedral site in pure LaAlO 3 is observed only in solutions doped with Ba. 3Q MAS NMR revealed that the broadening of this line is governed mainly by quadrupole coupling and allowed calculating the isotropic chemical shift [ru

Chemical effects of alkali atoms on critical temperature in superconducting alkali-doped fullerides

Science.gov (United States)

Hetfleisch, F.; Gunnarsson, O.; Srama, R.; Han, J. E.; Stepper, M.; Roeser, H.-P.; Bohr, A.; Lopez, J. S.; Mashmool, M.; Roth, S.

2018-03-01

Alkali metal doped fullerides (A3C60) are superconductors with critical temperatures, Tc, extending up to 38 K. Tc is known to depend strongly on the lattice parameter a, which can be adjusted by physical or chemical pressure. In the latter case an alkali atom is replaced by a different sized one, which changes a. We have collected an extensive data base of experimental data for Tc from very early up to recent measurements. We disentangle alkali atom chemical effects on Tc, beyond the well-known consequences of changing a. It is found that Tc, for a fixed a, is typically increased as smaller alkali atoms are replaced by larger ones, except for very large a. Possible reasons for these results are discussed. Although smaller in size than the lattice parameter contribution, the chemical effect is not negligible and should be considered in future physical model developments.

Ultraviolet optical absorption of alkali cyanides and alkali halide cyanides

International Nuclear Information System (INIS)

Souza Camargo Junior, S.A. de.

1982-09-01

The ultraviolet absorption spectra of alkali cyanide and mixed alkali halide cyanide crystals were measured at temperatures ranging from 300K down to 4.2K. A set of small absorption peaks was observed at energies near 6 eV and assigned to parity forbidden X 1 Σ + →a' 3 Σ + transitions of the CN - molecular ions. It was observed that the peak position depends on the alkali atom while the absorption cross section strongly depends on the halogen and on the CN - concentration of the mixed crystals. These effects are explained in terms of an interaction between the triplet molecular excitons and charge transfer excitons. The experimental data were fit with a coupling energy of a few meV. The coupling mechanism is discussed and it is found to be due to the overlap between the wave functions of the two excitations. (Author) [pt

EFFECTIVENESS OF USING DILUTE OXALIC ACID TO DISSOLVE HIGH LEVEL WASTE IRON BASED SLUDGE SIMULANT

International Nuclear Information System (INIS)

Ketusky, E

2008-01-01

At the Savannah River Site (SRS), near Aiken South Carolina, there is a crucial need to remove residual quantities of highly radioactive iron-based sludge from large select underground storage tanks (e.g., 19,000 liters of sludge per tank), in order to support tank closure. The use of oxalic acid is planned to dissolve the residual sludge, hence, helping in the removal. Based on rigorous testing, primarily using 4 and 8 wt% oxalic acid solutions, it was concluded that the more concentrated the acid, the greater the amount of residual sludge that would be dissolved; hence, a baseline technology on using 8 wt% oxalic acid was developed. In stark contrast to the baseline technology, reports from other industries suggest that the dissolution will most effectively occur at 1 wt% oxalic acid (i.e., maintaining the pH near 2). The driver for using less oxalic acid is that less (i.e., moles) would decrease the severity of the downstream impacts (i.e., required oxalate solids removal efforts). To determine the initial feasibility of using 1 wt% acid to dissolve > 90% of the sludge solids, about 19,000 liters of representative sludge was modeled using about 530,000 liters of 0 to 8 wt% oxalic acid solutions. With the chemical thermodynamic equilibrium based software results showing that 1 wt% oxalic acid could theoretically work, simulant dissolution testing was initiated. For the dissolution testing, existing simulant was obtained, and an approximate 20 liter test rig was built. Multiple batch dissolutions of both wet and air-dried simulant were performed. Overall, the testing showed that dilute oxalic acid dissolved a greater fraction of the stimulant and resulted in a significantly larger acid effectiveness (i.e., grams of sludge dissolved/mole of acid) than the baseline technology. With the potential effectiveness confirmed via simulant testing, additional testing, including radioactive sludge testing, is planned

Investigation of holmium(5) complexing in hydrofluoric acid solutions in the presence of alkali metal and ammonium fluorides

International Nuclear Information System (INIS)

Tsikaeva, D.V.; Agulyanskij, A.I.; Balabanov, Yu.I.; Kuznetsov, V.Ya.; Kalinnikov, V.T.

1989-01-01

Method of vibrational spectroscopy is used to study niobium-containing solutions of hydrofluoric acid in the presence of alkali metal and ammonium fluorides. It is shown that NbF 6 - and NbOF 5 2- ions co-exists in solutions, therewith, additions shift equilibrium to the second complex side. Methods of IR spectroscopy, roentgenometry, crystal optics and chemical analysis are used to identify precipitated from solutions solid phases. Three new phases, which composition by chemical analysis corresponds to M 3 Nb 2 OF 11 , where M=NH 4 , K, Rb, are detected. Their roentgenometric data displayed in tetragonal crystal system with a and c parameters equalling 15,710 and 7,744; 14,877 and 7,697; 15,511 and 7,785 A respectively, are presented

Pretreatment of Dried Distiller Grains with Solubles by Soaking in Aqueous Ammonia and Subsequent Enzymatic/Dilute Acid Hydrolysis to Produce Fermentable Sugars.

Science.gov (United States)

Nghiem, Nhuan P; Montanti, Justin; Kim, Tae Hyun

2016-05-01

Dried distillers grains with solubles (DDGS), a co-product of corn ethanol production in the dry-grind process, was pretreated by soaking in aqueous ammonia (SAA) using a 15 % w/w NH4OH solution at a solid/liquid ratio of 1:10. The effect of pretreatment on subsequent enzymatic hydrolysis was studied at two temperatures (40 and 60 °C) and four reaction times (6, 12, 24, and 48 h). Highest glucose yield of 91 % theoretical was obtained for the DDGS pretreated at 60 °C and 24 h. The solubilized hemicellulose in the liquid fraction was further hydrolyzed with dilute H2SO4 to generate fermentable monomeric sugars. The conditions of acid hydrolysis included 1 and 4 wt% acid, 60 and 120 °C, and 0.5 and 1 h. Highest yields of xylose and arabinose were obtained at 4 wt% acid, 120 °C, and 1 h. The fermentability of the hydrolysate obtained by enzymatic hydrolysis of the SAA-pretreated DDGS was demonstrated in ethanol fermentation by Saccharomyces cerevisiae. The fermentability of the hydrolysate obtained by consecutive enzymatic and dilute acid hydrolysis was demonstrated using a succinic acid-producing microorganism, strain Escherichia coli AFP184. Under the fermentation conditions, complete utilization of glucose and arabinose was observed, whereas only 47 % of xylose was used. The succinic acid yield was 0.60 g/g total sugar consumed.

Pyrolysis characteristic of kenaf studied with separated tissues, alkali pulp, and alkali li

Directory of Open Access Journals (Sweden)

Yasuo Kojima

2015-12-01

Full Text Available To estimate the potential of kenaf as a new biomass source, analytical pyrolysis was performed using various kenaf tissues, i.e., alkali lignin and alkali pulp. The distribution of the pyrolysis products from the whole kenaf was similar to that obtained from hardwood, with syringol, 4-vinylsyringol, guaiacol, and 4-vinylguaiacol as the major products. The phenols content in the pyrolysate from the kenaf core was higher than that from the kenaf cuticle, reflecting the higher lignin content of the kenaf core. The ratios of the syringyl and guaiacyl compounds in the pyrolysates from the core and cuticle samples were 2.79 and 6.83, respectively. Levoglucosan was the major pyrolysis product obtained from the kenaf alkali pulp, although glycol aldehyde and acetol were also produced in high yields, as previously observed for other cellulosic materials. Moreover, the pathways for the formation of the major pyrolysis products from alkali lignin and alkali pulp were also described, and new pyrolysis pathways for carbohydrates have been proposed herein. The end groups of carbohydrates bearing hemiacetal groups were subjected to ring opening and then they underwent further reactions, including further thermal degradation or ring reclosing. Variation of the ring-closing position resulted in the production of different compounds, such as furans, furanones, and cyclopentenones.

稀碱预处理棕榈残渣制备纤维乙醇%Pretreatment of oil palm residues by dilute alkali for cellulosic ethanol production

Institute of Scientific and Technical Information of China (English)

张海燕; 周玉杰; 李晋平; 戴玲妹; 刘德华; 张建安; Yuen May Choo; Soh Kheang Loh

2013-01-01

In the study, we used oil palm residues (empty fruit bunch, EFB) as raw material to produce cellulosic ethanol by pretreatment, enzymatic hydrolysis and fermentation. Firstly, the pretreatment of EFB with alkali, alkali/hydrogen peroxide and the effects on the components and enzymatic hydrolysis of cellulose were studied. The results show that dilute alkali was the suitable pretreatment method and the conditions were first to soak the substrate with 1% sodium hydroxide with a solid-liquid ratio of 1:10 at 40 ℃ for 24 h, and then subjected to 121 ℃ for 30 min. Under the conditions, EFB solid recovery was 74.09%, and glucan, xylan and lignin content were 44.08%, 25.74% and 13.89%, respectively. After separated with alkali solution, the pretreated EFB was washed and hydrolyzed for 72 h with 5% substrate concentration and 30 FPU/g dry mass (DM) enzyme loading, and the conversion of glucan and xylan reached 84.44% and 89.28%, respectively. We further investigated the effects of substrate concentration and enzyme loading on enzymatic hydrolysis and ethanol batch simultaneous saccharification and fermentation (SSF). The results show that when enzyme loading was 30 FPU/g DM and substrate concentration was increased from 5% to 25%, ethanol concentration were 9.76 g/L and 35.25 g/L after 72 h fermentation with Saccharomyces cerevisiae (inoculum size 5%, V/V), which was 79.09% and 56.96% of ethanol theory yield.%以棕榈残渣(Empty fruit bunch,EFB)为原料,通过预处理、酶解、发酵等过程制备纤维乙醇.首先对比了碱、碱/过氧化氢等预处理条件对棕榈残渣组成及酶解的影响,结果表明稀碱预处理效果较好.适宜的稀碱预处理条件为:NaOH浓度为1％,固液比为1∶10,在40℃浸泡24 h后于121℃下保温30 min,在该条件下,EFB的固体回收率为74.09％,纤维素、半纤维素和木质素的含量分别为44.08％、25.74％和13.89％.对该条件下预处理后的固体样品,以底物浓度5�

Structure peculiarities of mixed alkali silicate glasses

International Nuclear Information System (INIS)

Bershtein, V.A.; Gorbachev, V.V.; Egorov, V.

1980-01-01

The thermal porperties and structure of alkali and mixed alkali (Li, Na, K) silicate glasses by means of differential scanning calorimetry (DSC), the positron annihilation method, X-ray fluorescence and infrared (300-30 cm -1 ) spectroscopy were studied. Introduction of different alkali cations in glass results in nonadditive change in their electron structure (bond covalence degree growth) and the thermal behaviour. The different manifestations of mixed alkali effect can be explained by the lessening of long distance Coulomb interactions and strengthening the short-range forces in the mixed alkali glasses. (orig.)

Density of mixed alkali borate glasses: A structural analysis

International Nuclear Information System (INIS)

Doweidar, H.; El-Damrawi, G.M.; Moustafa, Y.M.; Ramadan, R.M.

2005-01-01

Density of mixed alkali borate glasses has been correlated with the glass structure. It is assumed that in such glasses each alkali oxide associates with a proportional quantity of B 2 O 3 . The number of BO 3 and BO 4 units related to each type of alkali oxide depends on the total concentration of alkali oxide. It is concluded that in mixed alkali borate glasses the volumes of structural units related to an alkali ion are the same as in the corresponding binary alkali borate glass. This reveals that each type of alkali oxide forms its own borate matrix and behaves as if not affected with the presence of the other alkali oxide. Similar conclusions are valid for borate glasses with three types of alkali oxide

Supporting Information Synthesis of fatty monoester lubricant base ...

Indian Academy of Sciences (India)

Synthesis of fatty monoester lubricant base oil catalyzed by Fe-Zn ... Physical properties of fatty acid monoesters viz., kinematic viscosity, viscosity index, density ... The analysis method involves titration of the diluted sample with ethanolic alkali ...

Incorporation of Mg and Ca into nanostructured Fe2O3 improves Fe solubility in dilute acid and sensory characteristics in foods.

Science.gov (United States)

Hilty, Florentine M; Knijnenburg, Jesper T N; Teleki, Alexandra; Krumeich, Frank; Hurrell, Richard F; Pratsinis, Sotiris E; Zimmermann, Michael B

2011-01-01

Iron deficiency is one of the most common micronutrient deficiencies worldwide. Food fortification can be an effective and sustainable strategy to reduce Fe deficiency but selection of iron fortificants remains a challenge. Water-soluble compounds, for example, FeSO(4), usually demonstrate high bioavailability but they often cause unacceptable sensory changes in foods. On the other hand, poorly acid-soluble Fe compounds, for example FePO(4), may cause fewer adverse sensory changes in foods but are usually not well bioavailable since they need to be dissolved in the stomach prior to absorption. The solubility and the bioavailability of poorly acid-soluble Fe compounds can be improved by decreasing their primary particle size and thereby increasing their specific surface area. Here, Fe oxide-based nanostructured compounds with added Mg or Ca were produced by scalable flame aerosol technology. The compounds were characterized by nitrogen adsorption, X-ray diffraction, transmission electron microscopy, and Fe solubility in dilute acid. Sensory properties of the Fe-based compounds were tested in 2 highly reactive, polyphenol-rich food matrices: chocolate milk and fruit yoghurt. The Fe solubility of nanostructured Fe(2)O(3) doped with Mg or Ca was higher than that of pure Fe(2)O(3). Since good solubility in dilute acid was obtained despite the inhomogeneity of the powders, inexpensive precursors, for example Fe- and Ca-nitrates, can be used for their manufacture. Adding Mg or Ca lightened powder color, while sensory changes when added to foods were less pronounced than for FeSO(4). The combination of high Fe solubility and low reactivity in foods makes these flame-made nanostructured compounds promising for food fortification. Practical Application: The nanostructured iron-containing compounds presented here may prove useful for iron fortification of certain foods; they are highly soluble in dilute acid and likely to be well absorbed in the gut but cause less severe

Facile Precursor for Synthesis of Silver Nanoparticles Using Alkali Treated Maize Starch

Science.gov (United States)

El-Rafie, M. H.; Ahmed, Hanan B.; Zahran, M. K.

2014-01-01

Silver nanoparticles were prepared by using alkali treated maize starch which plays a dual role as reducer for AgNO3 and stabilizer for the produced AgNPs. The redox reaction which takes a place between AgNO3 and alkali treated starch was followed up and controlled in order to obtain spherical shaped silver nanoparticles with mean size 4–6 nm. The redox potentials confirmed the principle role of alkali treatment in increasing the reducibility of starch macromolecules. The measurements of reducing sugars at the end of reaction using dinitrosalicylic acid reagent (DNS) were carried out in order to control the chemical reduction reaction. The UV/Vis spectra show that an absorption peak, occurring due to surface plasmon resonance (SPR), exists at 410 nm, which is characteristic to yellow color of silver nanoparticles solution. The samples have been characterized by transmission electron microscopy (TEM), which reveal the nanonature of the particles. PMID:27433508

Alkali-corrosion synthesis and excellent DSSC performance of novel jujube-like hierarchical TiO2 microspheres

Science.gov (United States)

Xiao, Jiajia; Li, Po; Wen, Xiaogang

2018-04-01

Novel jujube-like hierarchical TiO2 microspheres (HTMs) were synthesized by an alkali-corrosion process of titanium phosphate (Ti2O3(H2PO4)2 · 2H2O) microspheres. The hierarchical titanium phosphate microsphere (HTPM) intermediates consisting of nanoflakes with a thickness of 20 nm were firstly prepared by a facile hydrothermal method. After reacting with diluted NaOH at low temperature and atmospheric pressure, followed by subsequent acid washing and a calcination process, the HTPM intermediates were transformed to TiO2 with the microsphere morphology well retained, while the nanoflakes became porous, and some new nanowires were formed between the nanoflakes. Finally, HTMs consisting of porous nanoflakes and nanowires were obtained. The possible growth mechanisms of HTPMs and HTMs are discussed. The HTMs demonstrate high specific surface area and excellent light-scattering ability. The performance of the dye sensitized solar cells (DSSCs) of the HTMs synthesized under different conditions is studied, and a total conversion efficiency of up to 8.93% was obtained. The improved DSSC performance was attributed to the enhanced dye loading, light-scattering, and charge transporting ability of the HTMs with a unique hierarchical nanostructure.

High-alkali low-temperature polysulfide pulping (HALT) of Scots pine.

Science.gov (United States)

Paananen, Markus; Sixta, Herbert

2015-10-01

High-alkali low-temperature polysulfide pulping (HALT) was effectively utilised to prevent major polysaccharide losses while maintaining the delignification rate. A yield increase of 6.7 wt% on wood was observed for a HALT pulp compared to a conventionally produced kappa number 60 pulp with comparable viscosity. Approximately 70% of the yield increase was attributed to improved galactoglucomannan preservation and 30% to cellulose. A two-stage oxygen delignification sequence with inter-stage peroxymonosulphuric acid treatment was used to ensure delignification to a bleachable grade. In a comparison to conventional pulp, HALT pulp effectively maintained its yield advantage. Diafiltration trials indicate that purified black liquor can be directly recycled, as large lignin fractions and basically all dissolved polysaccharides were separated from the alkali-rich BL. Copyright © 2015 Elsevier Ltd. All rights reserved.

DFT study of the interaction between DOTA chelator and competitive alkali metal ions.

Science.gov (United States)

Frimpong, E; Skelton, A A; Honarparvar, B

2017-09-01

1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetracetic acid (DOTA) is an important chelator for radiolabeling of pharmaceuticals. The ability of alkali metals found in the body to complex with DOTA and compete with radio metal ions can alter the radiolabeling process. Non-covalent interactions between DOTA complexed with alkali metals Li + , Na + , K + and Rb + , are investigated with density functional theory using B3LYP and ωB97XD functionals. Conformational possibilities of DOTA were explored with a varying number of carboxylic pendant arms of DOTA in close proximity to the ions. It is found that the case in which four arms of DOTA are interacting with ions is more stable than other conformations. The objective of this study is to explore the electronic structure properties upon complexation of alkali metals Li + Na + , K + and Rb + with a DOTA chelator. Interaction energies, relaxation energies, entropies, Gibbs free energies and enthalpies show that the stability of DOTA, complexed with alkali metals decreases down the group of the periodic table. Implicit water solvation affects the complexation of DOTA-ions leading to decreases in the stability of the complexes. NBO analysis through the natural population charges and the second order perturbation theory, revealed a charge transfer between DOTA and alkali metals. Conceptual DFT-based properties such as HOMO/LUMO energies, ΔE HOMO-LUMO and chemical hardness and softness indicated a decrease in the chemical stability of DOTA-alkali metal complexes down the alkali metal series. This study serves as a guide to researchers in the field of organometallic chelators, particularly, radiopharmaceuticals in finding the efficient optimal match between chelators and various metal ions. Copyright © 2017 Elsevier Inc. All rights reserved.

(e, 2e) triple differential cross sections of alkali and alkali earth atoms: Na, K and Mg, Ca

International Nuclear Information System (INIS)

Hitawala, U; Purohit, G; Sud, K K

2008-01-01

Recently low-energy measurements have been reported for alkali targets Na and K and alkali earth targets Mg and Ca in coplanar symmetric geometry. We report the results of our calculation of triple differential cross section (TDCS) for electron impact single ionization (i.e. (e, 2e) processes) of alkali atoms Na, K and alkali earth atoms Mg, Ca in coplanar symmetric geometry. We have performed the present calculations using the distorted-wave Born approximation (DWBA) formalism at intermediate incident electron energies used in the recently performed experiments. Ionization takes place from the valence shell for all the targets investigated and the outgoing electrons share the excess energy equally. We have also considered the effect of target polarization in our DWBA calculations which may be an important quantity at incident electron energies used in the present investigation. We find that the DWBA formalism is able to reproduce most of the trend of experimental data and may provide a future direction for further investigation of ionization process on alkali and alkali earth metals. It is also observed that the second-order effects are more important to understand the collision dynamics of (e, 2e) processes on alkali earth targets

Construction of thermionic alkali-ion sources

International Nuclear Information System (INIS)

Ul Haq, F.

1986-01-01

A simple technique is described by which singly charged alkali ions of K, Na, Li, Rb and Cs are produced by heating ultra-pure chemical salts of different alkali metals on tungsten filaments without employing a temperature measuring device. The character of alkali-ion currents at different heating powers and the remarkably constant ion emission current for prolonged periods are discussed. (author)

Local structure of alkalis in mixed-alkali borate glass to elucidate the origin of mixed-alkali effect

Directory of Open Access Journals (Sweden)

Yomei Tokuda

2015-12-01

Full Text Available We report the structural analysis of Na+ and Cs+ in sodium cesium borate crystals and glasses using 23Na and 133Cs magic-angle spinning nuclear magnetic resonance (MAS NMR spectroscopy. The composition dependence of NMR spectra of the borate was similar to that of the silicate: (1 the peak position of cesium borate crystals shifted to upfield for structures with larger Cs+ coordination numbers, (2 the MAS NMR spectra of xNa2O-yCs2O-3B2O3 (x = 0, 0.25, 0.5, 0.75, 1.0, x + y = 1 glass showed that the average coordination number (CN of both the alkali cations decreases with increasing Cs+/(Na+ + Cs+ ratio. However, the degree of decrement in borates is much smaller than that in silicates. We have considered that the small difference in CN is due to 4-coordinated B, because it is electrically compensated by the alkali metal ions resulting in the restriction of having various coordinations of O to alkali metal.

Characteristics of Lignin Fractions from Dilute Acid Pretreated Switchgrass and Their Effect on Cellobiohydrolase from Trichoderma longibrachiatum

Directory of Open Access Journals (Sweden)

Lan Yao

2018-02-01

Full Text Available To investigate the interactions between acid pretreated switchgrass lignin and cellobiohydrolase (CBH, three different lignin fractions were isolated from dilute acid pretreated switchgrass by (i ethanol extraction, followed by (ii dioxane/H2O extraction, and (iii cellulase treatment, respectively. Structural properties of each lignin fraction were elucidated by GPC, 13C-NMR, and 2D-HSQC NMR analyses. The adsorptions of CBH to the isolated lignin fractions were also studied by Langmuir adsorption isotherms. Ethanol-extractable lignin fraction, mainly composed of syringyl (S and guaiacyl (G units, had the lowest molecular weight, while dioxane/H2O-extracted lignin fraction had the lowest S/G ratio with higher content of p-coumaric acid (pCA unit. The residual lignin fraction after enzymatic treatment had the highest S/G ratio without hydroxyphenyl (H unit. Strong associations were found between lignin properties such as lignin composition and S/G ratio and its non-productive enzyme adsorption factors including the maximum adsorption capacity and binding strength.

Coprecipitation of alkali metal ions with calcium carbonate

International Nuclear Information System (INIS)

Okumura, Minoru; Kitano, Yasushi

1986-01-01

The coprecipitation of alkali metal ions Li + , Na + , K + and Rb + with calcium carbonate has been studied experimentally and the following results have been obtained: (1) Alkali metal ions are more easily coprecipitated with aragonite than with calcite. (2) The relationship between the amounts of alkali metal ions coprecipitated with aragonite and their ionic radii shows a parabolic curve with a peak located at Na + which has approximately the same ionic radius as Ca 2+ . (3) However, the amounts of alkali metal ions coprecipitated with calcite decrease with increasing ionic radius of alkali metals. (4) Our results support the hypothesis that (a) alkali metals are in interstitial positions in the crystal structure of calcite and do not substitute for Ca 2+ in the lattice, but (b) in aragonite, alkali metals substitute for Ca 2+ in the crystal structure. (5) Magnesium ions in the parent solution increase the amounts of alkali metal ions (Li + , Na + , K + and Rb + ) coprecipitated with calcite but decrease those with aragonite. (6) Sodium-bearing aragonite decreases the incorporation of other alkali metal ions (Li + , K + and Rb + ) into the aragonite. (author)

Studies on the alkali-silica reaction rim in a simplified calcium-alkali-silicate system

NARCIS (Netherlands)

Zheng, Kunpeng; Adriaensens, Peter; De Schutter, Geert; Ye, G.; Taerwe, Luc

2016-01-01

This work is intended to provide a better understanding about the properties and roles of the reaction rim in an alkali-silica reaction. A simplified calcium-alkali-silicate system was created to simulate the multiple interactions among reactive silica, alkaline solution and portlandite near the

Gluconeogenesis from labeled carbon: estimating isotope dilution

International Nuclear Information System (INIS)

Kelleher, J.K.

1986-01-01

To estimate the rate of gluconeogenesis from steady-state incorporation of labeled 3-carbon precursors into glucose, isotope dilution must be considered so that the rate of labeling of glucose can be quantitatively converted to the rate of gluconeogenesis. An expression for the value of this isotope dilution can be derived using mathematical techniques and a model of the tricarboxylic acid (TCA) cycle. The present investigation employs a more complex model than that used in previous studies. This model includes the following pathways that may affect the correction for isotope dilution: 1) flux of 3-carbon precursor to the oxaloacetate pool via acetyl-CoA and the TCA cycle; 2) flux of 4- or 5-carbon compounds into the TCA cycle; 3) reversible flux between oxaloacetate (OAA) and pyruvate and between OAA and fumarate; 4) incomplete equilibrium between OAA pools; and 5) isotope dilution of 3-carbon tracers between the experimentally measured pool and the precursor for the TCA-cycle OAA pool. Experimental tests are outlined which investigators can use to determine whether these pathways are significant in a specific steady-state system. The study indicated that flux through these five pathways can significantly affect the correction for isotope dilution. To correct for the effects of these pathways an alternative method for calculating isotope dilution is proposed using citrate to relate the specific activities of acetyl-CoA and OAA

Method of handling radioactive alkali metal waste

Science.gov (United States)

Wolson, R.D.; McPheeters, C.C.

Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1.

Method of handling radioactive alkali metal waste

International Nuclear Information System (INIS)

Mcpheeters, C.C.; Wolson, R.D.

1980-01-01

Radioactive alkali metal is mixed with particulate silica in a rotary drum reactor in which the alkali metal is converted to the monoxide during rotation of the reactor to produce particulate silica coated with the alkali metal monoxide suitable as a feed material to make a glass for storing radioactive material. Silica particles, the majority of which pass through a 95 mesh screen or preferably through a 200 mesh screen, are employed in this process, and the preferred weight ratio of silica to alkali metal is 7 to 1 in order to produce a feed material for the final glass product having a silica to alkali metal monoxide ratio of about 5 to 1

Abnormal distal renal tubular acidification in patients with low bone mass: prevalence and impact of alkali treatment.

Science.gov (United States)

Sromicki, Jerzy Jan; Hess, Bernhard

2017-06-01

Chronic acid retention is known to promote bone dissolution. In this study, 23 % of patients with osteopenia/osteoporosis were diagnosed with abnormal distal renal tubular acidification (dRTA), a kidney dysfunction leading to chronic acid retention. Treating those patients with alkali-therapy shows improvement in bone density. To evaluate the prevalence of abnormal distal renal tubular acidification in patients with low bone mass (LBM) and the impact of additional alkali treatment on bone density in patients with concomitant LBM and dRTA,183 patients referred for metabolic evaluation of densitometrically proven low bone mass were screened for abnormal distal renal tubular acidification between 2006 and 2013. In all LBM urine pH (U-pH) was measured in the 2nd morning urines after 12 h of fasting. If U-pH was ≥5.80, LBM underwent a 1-day ammonium chloride loading, and U-pH was remeasured the next morning. If U-pH after acid loading did not drop below 5.45, patients were diagnosed with abnormal distal renal tubular acidification. Normal values were obtained from 21 healthy controls. All LBM with dRTA were recommended alkali citrate in addition to conventional therapy of LBM, and follow-up DXAs were obtained until 2014. 85 LBM underwent NH 4 Cl loading. 42 LBM patients were diagnosed with incomplete dRTA (idRTA; prevalence 23.0 %). During follow-up (1.6-8 years) of idRTA-LBM patients, subjects adhering to alkali treatment tended to improve BMD at all sites measured, whereas BMD of non-adherent idRTA patients worsened/remained unchanged. (1) About one out of four patients with osteopenia/osteoporosis has idRTA. (2) Upon NH 4 Cl loading, idRTA patients do not lower urine pH normally, but show signs of increased acid-buffering by bone dissolution. (3) In idRTA patients with low bone mass on conventional therapy, additional long-term alkali treatment improves bone mass at lumbar spine and potentially at other bone sites. (4) All patients with low bone mass undergoing

Alkali Influence on Synthesis of Solid Electrolyte Based on Alkali Nitrate-Alumina

International Nuclear Information System (INIS)

Yustinus Purwamargapratala; Purnama, S.; Purwanto, P.

2008-01-01

Research of solid electrolyte based on alumina with addition of alkali materials of barium nitrate, calcium nitrate, sodium nitrate and lithium nitrate has been done. Aluminium hydroxide and alkali nitrate were mixed in mole ratio of 1 : 1 in water media and pyrolyzed at 300 o C for 1 hour Pyrolysis result were then mixed with alumina in mole ratio of 1 : 1, compacted and heated at 600 o C for 3 hours. To characterize the sample, XRD (X-Ray Diffractometers) and LCR meter (impedance, capacitance, and resistance) were used for analysis the phase and conductivity properties. The result showed formation of alkali-aluminate in which Li-base have the highest room temperature conductivity of 3.1290 x 10 -5 S.cm -1 , while Ba-base have the lowest conductivity of 5.7266 x 10 -8 S.cm -1 . (author)

Thermodynamic properties of alkali borosilicate gasses and metaborates

International Nuclear Information System (INIS)

Asano, Mitsuru

1992-01-01

Borosilicate glasses are the proposed solidifying material for storing high level radioactive wastes in deep underground strata. Those have low melting point, and can contain relatively large amount of high level radioactive wastes. When borosilicate glasses are used for this purpose, they must be sufficiently stable and highly reliable in the vitrification process, engineered storage and the disposal in deep underground strata. The main vaporizing components from borosilicate glasses are alkali elements and boron. In this report, as for the vaporizing behavior of alkali borosilicate glasses, the research on thermodynamic standpoint carried out by the authors is explained, and the thermodynamic properties of alkali metaborates of monomer and dimer which are the main evaporation gases are reported. The evaporation and the activity of alkali borosilicate glasses, the thermodynamic properties of alkali borosilicate glasses, gaseous alkali metaborates and alkali metaborate system solid solution and so on are described. (K.I.)

Physical and optical studies in mixed alkali borate glasses with three types of alkali ions

International Nuclear Information System (INIS)

Samee, M.A.; Awasthi, A.M.; Shripathi, T.; Bale, Shashidhar; Srinivasu, Ch.; Rahman, Syed

2011-01-01

Research highlights: → We report, for the first time, the mixed alkali effect in the (40-x)Li 2 O-xNa 2 O-10K 2 O-50B 2 O 3 glasses through optical properties, density and modulated DSC studies. → Optical band gap (E opt ) and Urbach energy (ΔE) have been evaluated. → The values of E opt and ΔE show non-linear behavior with compositional parameter showing the mixed alkali effect. → The glass stability S is observed to be less which may be important for the present glasses as promising material for non-optical applications. - Abstract: So far only a handful of publications have been concerned with the study of the mixed alkali effect in borate glasses containing three types of alkali ions. In the present work, the mixed alkali effect (MAE) has been investigated in the glass system (40-x)Li 2 O-xNa 2 O-10K 2 O-50B 2 O 3 . (0 ≤ x ≤ 40 mol%) through density and modulated DSC studies. The density and glass transition temperature of the present glasses varies non-linearly exhibiting mixed alkali effect. The glass stability is observed to be less which may be important for the present glasses as promising material for non-optical applications. We report, for the first time, the mixed alkali effect in the present glasses through optical properties. From the absorption edge studies, the values of indirect optical band gap (E opt ), direct optical band gap and Urbach energy (ΔE) have been evaluated. The values of E opt and ΔE show non-linear behavior with compositional parameter showing the mixed alkali effect. The average electronic polarizability of oxide ions α O 2- , optical basicity Λ, and Yamashita-Kurosawa's interaction parameter A have been examined to check the correlations among them and bonding character. Based on good correlation among electronic polarizability of oxide ions, optical basicity and interaction parameter, the present Li 2 O-Na 2 O-K 2 O-B 2 O 3 glasses are classified as normal ionic (basic) oxides.

Cation-Size-Dependent Conformational Locking of Glutamic Acid by Alkali Ions: Infrared Photodissociation Spectroscopy of Cryogenic Ions.

Science.gov (United States)

Klyne, Johanna; Bouchet, Aude; Ishiuchi, Shun-Ichi; Fujii, Masaaki; Dopfer, Otto

2018-03-01

Consolidated knowledge of conformation and stability of amino acids and their clusters is required to understand their biochemical recognition. Often, alkali ions interact with amino acids and proteins. Herein, infrared photodissociation (IRPD) spectra of cryogenic metalated glutamic acid ions (GluM + , M = Li-Cs) are systematically analyzed in the isomer-specific fingerprint and XH stretch ranges (1100-1900, 2600-3600 cm -1 ) to provide a direct measure for cation-size-dependent conformational locking. GluM + ions are generated by electrospray ionization and cooled down to 15 K in a cryogenic quadrupole ion trap. The assignment of the IRPD spectra is supported by density functional theory calculations at the dispersion-corrected B3LYP-D3/aug-cc-pVTZ level. In the global minimum of GluM + , the flexibility of Glu is strongly reduced by the formation of rigid ionic CO···M + ···OC metal bridges, corresponding to charge solvation. The M + binding energy decreases monotonically with increasing cation size from D 0 = 314 to 119 kJ/mol for Li-Cs. Whereas for Li and Na only the global minimum of GluM + is observed, for K-Cs at least three isomers exist at cryogenic temperature. The IRPD spectra of cold GluM + ions are compared to IR multiple-photon dissociation spectra measured at room temperature. Furthermore, we elucidate the differences of the impact of protonation and metalation on the structure and conformational locking of Glu.

Isolation and structural characterization of sugarcane bagasse lignin after dilute phosphoric acid plus steam explosion pretreatment and its effect on cellulose hydrolysis

Science.gov (United States)

Jijiao Zeng; Zhaohui Tong; Letian Wang; J.Y. Zhu; Lonnie Ingram

2014-01-01

The structure of lignin after dilute phosphoric acid plus steam explosion pretreatment process of sugarcane bagasse in a pilot scale and the effect of the lignin extracted by ethanol on subsequent cellulose hydrolysis were investigated. The lignin structural changes caused by pretreatment were identified using advanced nondestructive techniques such as gel permeation...

Solubilization of tea seed oil in a food-grade water-dilutable microemulsion.

Directory of Open Access Journals (Sweden)

Lingli Deng

Full Text Available Food-grade microemulsions containing oleic acid, ethanol, Tween 20, and water were formulated as a carrier system for tea seed oil (Camellia oleifera Abel.. The effect of ethanol on the phase behavior of the microemulsion system was clearly reflected in pseudo-ternary diagrams. The solubilization capacity and solubilization efficiency of tea seed oil dispersions were measured along the dilution line at a 70/30 surfactant/oil mass ratio with Tween 20 as the surfactant and oleic acid and ethanol (1:3, w/w as the oil phase. The dispersed phase of the microemulsion (1.5% weight ratio of tea seed oil to the total amount of oil, surfactant, and tea seed oil could be fully diluted with water without phase separation. Differential scanning calorimetry and viscosity measurements indicated that both the carrier and solubilized systems underwent a similar microstructure transition upon dilution. The dispersion phases gradually inverted from the water-in-oil phase ( 45% water along the dilution line.

Relation between the electroforming voltage in alkali halide-polymer diodes and the bandgap of the alkali halide

International Nuclear Information System (INIS)

Bory, Benjamin F.; Wang, Jingxin; Janssen, René A. J.; Meskers, Stefan C. J.; Gomes, Henrique L.; De Leeuw, Dago M.

2014-01-01

Electroforming of indium-tin-oxide/alkali halide/poly(spirofluorene)/Ba/Al diodes has been investigated by bias dependent reflectivity measurements. The threshold voltages for electrocoloration and electroforming are independent of layer thickness and correlate with the bandgap of the alkali halide. We argue that the origin is voltage induced defect formation. Frenkel defect pairs are formed by electron–hole recombination in the alkali halide. This self-accelerating process mitigates injection barriers. The dynamic junction formation is compared to that of a light emitting electrochemical cell. A critical defect density for electroforming is 10 25 /m 3 . The electroformed alkali halide layer can be considered as a highly doped semiconductor with metallic transport characteristics

40 CFR 721.4740 - Alkali metal nitrites.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal nitrites. 721.4740... Substances § 721.4740 Alkali metal nitrites. (a) Chemical substances and significant new use subject to reporting. (1) The category of chemical substances which are nitrites of the alkali metals (Group IA in the...

Method for the safe disposal of alkali metal

International Nuclear Information System (INIS)

Johnson, T.R.

1977-01-01

Alkali metals such as those employed in liquid metal coolant systems can be safely reacted to form hydroxides by first dissolving the alkali metal in relatively inert metals such as lead or bismuth. The alloy thus formed is contacted with a molten salt including the alkali metal hydroxide and possibly the alkali metal carbonate in the presence of oxygen. This oxidizes the alkali metal to an oxide which is soluble within the molten salt. The salt is separated and contacted with steam or steam--CO 2 mixture to convert the alkali metal oxide to the hydroxide. These reactions can be conducted with minimal hydrogen evolution and with the heat of reaction distributed between the several reaction steps. 5 claims, 1 figure

Elastic modulus of the alkali-silica reaction rim in a simplified calcium-alkali-silicate system determined by nano-indentation

NARCIS (Netherlands)

Zheng, Kunpeng; Lukovic, M.; De Schutter, Geert; Ye, G.; Taerwe, Luc

2016-01-01

This work aims at providing a better understanding of the mechanical properties of the reaction rim in the alkali-silica reaction. The elastic modulus of the calcium alkali silicate constituting the reaction rim, which is formed at the interface between alkali silicate and Ca(OH)2 in a

Ionic conductivity of polymer gels deriving from alkali metal ionic liquids and negatively charged polyelectrolytes

International Nuclear Information System (INIS)

Ogihara, Wataru; Sun Jiazeng; Forsyth, Maria; MacFarlane, Douglas R.; Yoshizawa, Masahiro; Ohno, Hiroyuki

2004-01-01

We have prepared polymer gel electrolytes with alkali metal ionic liquids (AMILs) that inherently contain alkali metal ions. The AMIL consisted of sulfate anion, imidazolium cation, and alkali metal cation. AMILs were mixed directly with poly(3-sulfopropyl acrylate) lithium salt or poly(2-acrylamido-2-methylpropanesulfonic acid) lithium salt to form polymer gels. The ionic conductivity of these gels decreased with increasing polymer fraction, as in general ionic liquid/polymer mixed systems. At low polymer concentrations, these gels displayed excellent ionic conductivity of 10 -4 to 10 -3 S cm -1 at room temperature. Gelation was found to cause little change in the 7 Li diffusion coefficient of the ionic liquid, as measured by pulse-field-gradient NMR. These data strongly suggest that the lithium cation migrates in successive pathways provided by the ionic liquids

Biodiesel production by transesterification of duck tallow with methanol on alkali catalysts

Energy Technology Data Exchange (ETDEWEB)

Chung, Kyong-Hwan [Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju 500-757 (Korea); Kim, Jin [Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju 500-757 (Korea)]|[Department of Advanced Chemicals Graduate School, Chonnam National University, Gwangju 500-757 (Korea); Lee, Ki-Young [Center for Functional Nano Fine Chemicals, Chonnam National University, Gwangju 500-757 (Korea)]|[Department of Applied Chemical Engineering and The Research Institute for Catalysis, Chonnam National University, Gwangju 500-757 (Korea)

2009-01-15

Duck tallow was employed as a feedstock for the production of biodiesel by transesterification with methanol. The content of fatty acid methyl ester (FAME) was evaluated on various alkali catalysts during transesterification. The composition and chemical properties of the FAME were investigated in the raw duck tallow and the biodiesel products. The major constituent in the biodiesel product was oleic acid. The FAME content was 97% on KOH catalyst in the reaction. It was acceptable for the limit of European biodiesel qualities for BD100. Acid value, density, and kinematic viscosity of the biodiesel products also came up to the biodiesel qualities. (author)

Direct determination of mercury in cosmetic samples by isotope dilution inductively coupled plasma mass spectrometry after dissolution with formic acid

Energy Technology Data Exchange (ETDEWEB)

Gao, Ying; Shi, Zeming; Zong, Qinxia; Wu, Peng; Su, Jing [Sichuan Provincial Key Laboratory of Nuclear Technology in Geology, College of Nuclear Technology and Automation Engineering, Chengdu University of Technology, Chengdu 610059 (China); Liu, Rui, E-mail: liur.ray@gmail.com [Mineral Resources Chemistry Key Laboratory of Sichuan Higher Education Institutions, College of Materials and Chemistry and Chemical Engineering, Chengdu University of Technology, Chengdu 610059 (China)

2014-02-17

Graphical abstract: -- Highlights: •Simple, sensitive, and accurate method is established for mercury determination in cosmetics. •The sample preparation procedure is highly simplified. •Isotope dilution efficiently eliminates matrix effect. •First report of using formic acid based method in combination with PVG-ID-ICP MS for mercury quantitation in cosmetics. -- Abstract: A new method was proposed for the accurate determination of mercury in cosmetic samples based on isotopic dilution (ID)-photochemical vapor generation (PVG)-inductively coupled plasma mass spectrometry (ICP MS) measurement. Cosmetic samples were directly dissolved in formic acid solution and subsequently subjected to PVG for the reduction of mercury into vapor species following by ICP MS detection. Therefore, the risks of analyte contamination and loss were avoided. Highly enriched {sup 201}Hg isotopic spike is added to cosmetics and the isotope ratios of {sup 201}Hg/{sup 202}Hg were measured for the quantitation of mercury. With ID calibration, the influences originating from sample matrixes for the determination of mercury in cosmetic samples have been efficiently eliminated. The effects of several experimental parameters, such as the concentration of the formic acid, and the flow rates of carrier gas and sample were investigated. The method provided good reproducibility and the detection limits were found to be 0.6 pg mL{sup −1}. Finally, the developed method was successfully applied for the determination of mercury in six cosmetic samples and a spike test was performed to verify the accuracy of the method.

Alkali binding in hydrated Portland cement paste

NARCIS (Netherlands)

Chen, Wei; Brouwers, Jos

2010-01-01

The alkali-binding capacity of C–S–H in hydrated Portland cement pastes is addressed in this study. The amount of bound alkalis in C–S–H is computed based on the alkali partition theories firstly proposed by Taylor (1987) and later further developed by Brouwers and Van Eijk (2003). Experimental data

Alkali-aggregate reactivity (AAR) facts book.

Science.gov (United States)

2013-03-01

This document provides detailed information on alkali-aggregate reactivity (AAR). It primarily discusses alkali-silica reaction (ASR), covering the chemistry, symptoms, test methods, prevention, specifications, diagnosis and prognosis, and mitigation...

An alternative picture of alkali-metal-mediated metallation: cleave and capture chemistry.

Science.gov (United States)

Mulvey, Robert E

2013-05-21

This perspective article takes an alternative look at alkali-metal-mediated chemistry (exchange of a relatively inert C-H bond for a more reactive C-metal bond by a multicomponent reagent usually containing an alkali metal and a less electropositive metal such as magnesium or zinc). It pictures that the cleavage of selected C-H bonds can be accompanied by the capturing of the generated anion by the multi (Lewis acid)-(Lewis base) character of the residue of the bimetallic base. In this way small atoms or molecules (hydrides, oxygen-based anions) as well as sensitive organic anions (of substituted aromatic compounds, ethers or alkenes) can be captured. Cleave and capture reactions which occur in special positions on the organic substrate are also included.

Alkali depletion and ion-beam mixing in glasses

International Nuclear Information System (INIS)

Arnold, G.W.

1983-01-01

Ion-implantation-induced alkali depletion in simple alkali-silicate glasses (12M 2 O.88SiO 2 ) has been studied for implantations at room temperature and near 77K. Results are consistent with a mechanism for alkali removal, by heavy ion bombardment, based on radiation-enhanced migration and preferential removal of alkali from the outermost layers. Similar results were obtained for mixed-alkali glasses ((12-x)Cs 2 .O.xM 2 O.88SiO 2 ) where, in addition, a mixed-alkali effect may also be operative. Some preliminary experiments with ion implantation through thin Al films on SiO 2 glass and on a phosphate glass show that inter-diffusion takes place and suggest that this ion-mixing technique may be a useful method for altering the physical properties of glass surfaces

Ionic interactions in alkali-aluminium tetrafluoride clusters

International Nuclear Information System (INIS)

Akdeniz, Z.; Cicek, Z.; Karaman, A.; Pastore, G.; Tosi, M.P.

1999-08-01

Complex anion structures ((AlF 4 ) - , (AlF 5 ) 2- and (AlF 6 ) 3- ) coexist in liquid mixtures of aluminium trifluoride and alkali fluorides in composition-dependent relative concentrations and are known to interact with the alkali counterions. We present a comparative study of the static and vibrational structures of MAlF 4 molecules (with M = any alkali), with the aim of developing and testing a refined model of the ionic interactions for applications to the Al-M fluoride mixtures. We find that, whereas an edge-bridged coordination is strongly favoured for Li in LiAIF 4 , edge-bridging and face-bridging of the alkali ion become energetically equivalent as one moves from Na to the heavier alkalis. This result is sensitive to the inclusion of alkali polarizability and may be interpreted as implying (for M = K, Rb or Cs) almost free relative rotations of the M + and (AlF 4 ) - partners at temperatures of relevance to experiment. The consistency of such a viewpoint with electron diffraction data on vapours and with Raman spectra on melts is discussed. (author)

Disruption of sugarcane bagasse lignocellulosic structure by means of dilute sulfuric acid pretreatment with microwave-assisted heating

International Nuclear Information System (INIS)

Chen, Wei-Hsin; Tu, Yi-Jian; Sheen, Herng-Kuang

2011-01-01

Highlights: → Pretreatment of dilute sulfuric acid on bagasse using microwave heating. → An increase in reaction temperature destroyed bagasse significantly. → Pretreated bagasse particles were characterized by fragmentation and swelling. → When the temperature was 190 o C, the fragmentation of particles became pronounced. → The influence of heating time on bagasse structure was not significant. - Abstract: Disruption of lignocellulosic structure of biomass plays a key role in producing bioethanol from lignocelluloses. This study investigated the impact of dilute sulfuric acid pretreatment on bagasse structure using microwave heating. Three reaction temperatures of 130, 160 and 190 o C with two heating times of 5 and 10 min were considered and a number of instruments were employed to analyze the properties of the bagasse particles. On account of microwave irradiation into the solution with dielectric heating, the experiments indicated that an increase in reaction temperature destroyed the lignocellulosic structure of bagasse in a significant way. The pretreated bagasse particles were simultaneously characterized by fragmentation and swelling. When the reaction temperature was as high as 190 o C, the fragmentation of particles became fairly pronounced so that the specific surface area of the pretreated material grew substantially. Meanwhile, almost all hemicellulose was removed from bagasse and the crystalline structure of cellulose disappeared. In contrast, the feature of lignin was remained clearly. However, a comparison between the heating times of 5 and 10 min revealed that the influence of the heating time on the lignocellulosic structure was not significant, indicating that the pretreatment with 5 min was sufficiently long.

Effects of SPORL and dilute acid pretreatment on substrate morphology, cell physical and chemical wall structures, and subsequent enzymatic hydrolysis of lodgepole pine

Science.gov (United States)

Xinping Li; Xiaolin Luo; Kecheng Li; J.Y. Zhu; J. Dennis Fougere; Kimberley Clarke

2012-01-01

The effects of pretreatment by dilute acid and sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) on substrate morphology, cell wall physical and chemical structures, along with the subsequent enzymatic hydrolysis of lodgepole pine substrate were investigated. FE-SEM and TEM images of substrate structural morphological changes showed that SPORL...

(abstract) Experimental and Modeling Studies of the Exchange Current at the Alkali Beta'-Alumina/Porous Electrode/Alkali Metal Vapor Three Phase Boundary

Science.gov (United States)

Williams, R. M.; Jeffries-Nakamura, B.; Ryan, M. A.; Underwood, M. L.; O'Connor, D.; Kikkert, S.

1993-01-01

The microscopic mechanism of the alkali ion-electron recombination reaction at the three phase boundary zone formed by a porous metal electrode in the alkali vapor on the surface of an alkali beta'-alumina solid electrolyte (BASE) ceramic has been studied by comparison of the expected rates for the three simplest reaction mechanisms with known temperature dependent rate data; and the physical parameters of typical porous metal electrode/BASE/alkali metal vapor reaction zones. The three simplest reactions are tunneling of electrons from the alkali coated electrode to a surface bound alkali metal ion; emission of an electron from the electrode with subsequent capture by a surface bound alkali metal ion; and thermal emission of an alkali cation from the BASE and its capture on the porous metal electrode surface where it may recombine with an electron. Only the first reaction adequately accounts for both the high observed rate and its temperature dependence. New results include crude modeling of simple, one step, three phase, solid/solid/gas electrochemical reaction.

Pelindian Logam Tanah Jarang dari Terak Timah dengan Asam Klorida setelah Proses Fusi Alkali

Directory of Open Access Journals (Sweden)

Kurnia Trinopiawan

2016-05-01

Full Text Available Tin slag, a waste product from tin smelting process, has a potency to be utilized further by extracting the valuable metals inside, such as rare earth elements(REE. The objective of this study is to determine the optimum leaching condition of REE from tin slag after alkali fusion. Silica structure in slag is causing the direct leaching uneffective. Therefore, pre-treatment step using alkali fusion is required to break the structure of silica and to increase the porosity of slag. Fusion is conducted in 2 hours at 700 oC, with ratio of natrium hidroxide (NaOH : slag = 2 : 1. Later, frit which is leached by water then leached by chloride acid to dissolve REE. As much as 87,5% of REE is dissolved at 2 M on chloride acid (HCl concentration, in 40o C temperature, -325 mesh particle size, 15g/100ml of S/L, 150 rpm of agitation speed, and 5 minutes of leaching time

Effect of alkali ion on relaxation properties of binary alkali-borate glasses

International Nuclear Information System (INIS)

Lomovskoj, V.A.; Bartenev, G.M.

1992-01-01

Method of relaxation spectrometry were used to analyze the data on internal friction spectra of lithium, sodium, potassium and rubidium alkali-borate glasses in wide range of temperatures and frequencies. The nature of two relaxation processes was clarified: β m -process, related with mobility of alkaline metal cations, and α-process (vitrification), conditioned by system transformation from viscous-flow to vitreous state. It is shown that atomic-molecular mechanism of vitrification process changes when passing from vitreous B 2 O 3 to alkali-borate glasses

Charge transfer in gold--alkali-metal systems

International Nuclear Information System (INIS)

Watson, R.E.; Weinert, M.

1994-01-01

Based on conventional electronegativity arguments, gold--alkali-metal compounds are expected to be among the most ''ionic'' of metallic compounds. The concepts of ionicity and charge transfer are difficult to quantify. However, the changes in bonding in the 50/50 Au--alkali-metal systems between the elemental metals and the compounds are so severe that observations can readily be made concerning their character. The results, as obtained from self-consistent electronic-structure calculations, lead to the apparently odd observation that the electron density at the alkali-metal sites in the compound increases significantly and this involves high l componennts in the charge density. This increase, however, can be attributed to Au-like orbitals spatially overlapping the alkali-metal sites. In a chemical sense, it is reasonable to consider the alkali-metal transferring charge to these Au orbitals. While normally the difference in heats of formation between muffin-tin and full-potential calculations for transition-metal--transition-metal and transition-metal--main-group (e.g., Al) compounds having high site symmetry are small, for the gold--alkali-metal systems, the changes in bonding in the compounds cause differences of ∼0.5 eV/atom between the two classes of potential. Any serious estimate of the electronic structure in these systems must account for these aspherical bonding charges. The origin of the semiconducting behavior of the heavy-alkali-metal Au compounds is shown to arise from a combination of the Au-Au separations and the ionic character of the compounds; the light-alkali-metal Au compounds, with their smaller Au-Au separations, do not have a semiconducting gap. Core-level shifts and isomer shifts are also briefly discussed

An evaluation of dilute acid and ammonia fiber explosion pretreatment for cellulosic ethanol production.

Science.gov (United States)

Mathew, Anil Kuruvilla; Parameshwaran, Binod; Sukumaran, Rajeev Kumar; Pandey, Ashok

2016-01-01

The challenge associated with cellulosic ethanol production is maximizing sugar yield at low cost. Current research is being focused to develop a pretreatment method to overcome biomass recalcitrance in an efficient way. This review is focused on two major pretreatments: dilute acid (DA) and ammonia fiber explosion (AFEX) pretreatment of corn stover and how these pretreatment cause morphological and chemical changes to corn stover in order to overcome the biomass recalcitrance. This review highlights the key differences of these two pretreatments based on compositional analysis, cellulose and its crystallinity, morphological changes, structural changes to lignin, enzymatic reactivity and enzyme adsorption onto pretreated solids and finally cellulosic ethanol production from the hydrolysate of DA and AFEX treated corn stover. Each stage of the process, AFEX pretreated corn stover was superior to DA treated corn stover. Copyright © 2015 Elsevier Ltd. All rights reserved.

Method of making alkali metal hydrides

Science.gov (United States)

Pecharsky, Vitalij K.; Gupta, Shalabh; Pruski, Marek; Hlova, Ihor; Castle, Andra

2017-05-30

A method is provided for making alkali metal hydrides by mechanochemically reacting alkali metal and hydrogen gas under mild temperature (e.g room temperature) and hydrogen pressure conditions without the need for catalyst, solvent, and intentional heating or cooling.

Stable isotope dilution HILIC-MS/MS method for accurate quantification of glutamic acid, glutamine, pyroglutamic acid, GABA and theanine in mouse brain tissues.

Science.gov (United States)

Inoue, Koichi; Miyazaki, Yasuto; Unno, Keiko; Min, Jun Zhe; Todoroki, Kenichiro; Toyo'oka, Toshimasa

2016-01-01

In this study, we developed the stable isotope dilution hydrophilic interaction liquid chromatography with tandem mass spectrometry (HILIC-MS/MS) technique for the accurate, reasonable and simultaneous quantification of glutamic acid (Glu), glutamine (Gln), pyroglutamic acid (pGlu), γ-aminobutyric acid (GABA) and theanine in mouse brain tissues. The quantification of these analytes was accomplished using stable isotope internal standards and the HILIC separating mode to fully correct the intramolecular cyclization during the electrospray ionization. It was shown that linear calibrations were available with high coefficients of correlation (r(2)  > 0.999, range from 10 pmol/mL to 50 mol/mL). For application of the theanine intake, the determination of Glu, Gln, pGlu, GABA and theanine in the hippocampus and central cortex tissues was performed based on our developed method. In the region of the hippocampus, the concentration levels of Glu and pGlu were significantly reduced during reality-based theanine intake. Conversely, the concentration level of GABA increased. This result showed that transited theanine has an effect on the metabolic balance of Glu analogs in the hippocampus. Copyright © 2015 John Wiley & Sons, Ltd.

Alternative alkali resistant deNO{sub x} technologies

Energy Technology Data Exchange (ETDEWEB)

Buus Kristensen, S.; Due-Hansen, J.; Putluru, S.S.R.; Kunov-Kruse, A.; Fehrmann, R.; Degn Jensen, A.

2011-04-15

The aim of the project is to identify, make and test possible alkali resistant deNO{sub x} catalysts for use in biomass, waste or fossil fuelled power plants, where the flue gas typically has a high level of potassium compounds, which rapidly de-activate the traditional V{sub 2}O{sub 5}/TiO{sub 2} catalyst. Furthermore, new technologies are investigated based on a protective coating of the catalyst elements and selective reversible absorption of NO{sub x} with ionic liquids. Several promising alternative deNO{sub x} catalyst types have been made during the project: 1) V, Fe, CU based nano-TiO{sub 2} and nano-TiO{sub 2}-SO{sub 4}{sup 2-} catalysts; 2) V/ZrO{sub 2}-SO{sub 2}- and V/ZrO{sub 2}-CeO{sub 2} catalysts; V, Fe, Cu based Zeolite catalysts; 4) V, Fe, Cu based Heteropoly acid catalysts. Several of these are promising alternatives to the state-of the art industrial reference catalyst. All catalysts prepared in the present project exhibit higher to much higher alkali resistance compared to the commercial reference. Furthermore, two catalysts, i.e. 20 wt% V{sub 2}O-3-TiO{sub 2} nano-catalyst and the 4 wt% CuO-Mordenite zeolite based catalyst have also a higher initial SCR activity compared to the commercial one before alkali poisoning. Thus, those two catalysts might be attractive for SCR deNO{sub x} purposes even under ''normal'' fuel conditions in power plants and elsewhere making them strong candidates for further development. These efforts regarding all the promising catalysts will be pursued after this project has expired through a one year Proof of Concept project granted by the Danish Agency for Science, Technology and Innovation. Also the severe rate of deactivation due to alkali poisons can be avoided by coating the vanadium catalyst with Mg. Overall, the protective coating of SCR catalysts developed in the project seems promising and a patent application has been filed for this technology. Finally, a completely different approach to

Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

African Journals Online (AJOL)

NICOLAAS

2014-06-23

Jun 23, 2014 ... The influence of deanol on the corrosion behaviour of mild steel in dilute sulphuric acid with sodium ... the formation of a complex precipitate of protective film, which ... silicon carbide abrasive papers of 80, 120, 220, 800 and 1000 grit ...... ions in sulphuric acid on the corrosion behaviour of stainless steel,.

Calcium silicate hydrate: Crystallisation and alkali sorption

International Nuclear Information System (INIS)

Hong, S.

2000-01-01

Homogeneous single C-S-H gels has been prepared for the investigation of alkali binding potential and crystallisation. A distribution coefficient, R d , was introduced to express the partition of alkali between solid and aqueous phases at 25 deg. C. R d is independent of alkali hydroxide concentration and depends only on Ca:Si ratio over wide ranges of alkali concentration. The trend of numerical values of R d indicates that alkali bonding into the solid improves as its Ca:Si ratio decreases. Reversibility is demonstrated, indicating a possibility of constant R d value of the material. Al has been introduced to form C-A-S-H gels and their alkali sorption properties also determined. Al substituted into C-S-H markedly increases R d , indicating enhancement of alkali binding. However, the dependence of R d on alkali concentration is non-ideal with composition. A two-site model for bonding is presented. Crystallisation both under saturated steam and 1 bar vapour pressure has been investigated. It has been shown that heat treatment by saturated steam causes crystallisation of gels. The principal minerals obtained were (i) C-S-H gel and Ca(OH) 2 at -55 deg. C, (ii) 1.1 nm tobermorite, jennite and afwillite at 85 -130 deg. C, and (iii) xonotlite, foshagite and hillebrandite at 150-180 deg. C. Properties of crystalline C-S-H were also reported for reversible phase transformation, pH conditioning ability, seeding effect and solubility. At 1 bar pressure, crystallisation is slower than in saturated steam due to lower water activity. Tobermorite-like nanodomains develop during reaction at low Ca/Si ratios. In some Ca-rich compositions, Ca(OH) 2 is exsolved and occurs as nano-sized crystallites. (author)

Bioethanol productions from rice polish by optimization of dilute acid ...

African Journals Online (AJOL)

Lignocellulose materials are abundant renewable resource for the production of biofuel from fermentative organism (Sacchromyces cervesiae). Rice polish is cheapest and abundant lignocelluloses resource and has potential to produce bioethanol. The main steps for the conversion of biomass into glucose required dilute ...

A prosposed mechanism for the inactivation of atopic allergens in dilute solution

NARCIS (Netherlands)

Berrens, L.

A study has been made of the ultra-violet absorption spectra of purified atopic allergens at pH 2 and pH 12. The colour change of atopen solutions from deep brown in alakali to light brown or yellow in acid is reflected in the spectra by considerably higher extinction coefficients in alkali. By

Relaxation of quadrupole orientation in an optically pumped alkali vapour

Energy Technology Data Exchange (ETDEWEB)

Bernabeu, E; Tornos, J

1985-04-01

The relaxation of quadrupole orientation (alignment) in an optically pumped alkali vapour is theoretically studied by taking into account the relaxation processes by alkali-buffer gas, alkali-alkali with spin exchange and alkali-cell wall (diffusion process) collisions. The relaxation transients of the quadrupole orientation are obtained by introducing a first-order weak-pumping approximation (intermediate pumping) less restrictive than the usually considered (zeroth order) one.

PENGARUH PROSES DELIGNIFIKASI PADA PRODUKSI GLUKOSA DARI TONGKOL JAGUNG DENGAN HIDROLISIS ASAM ENCER

Directory of Open Access Journals (Sweden)

Primata Mardina

2013-10-01

Full Text Available The dilute acid hydrolysis of corn cob for glucose production has faced barrier because of lignin. In this research, an effective lignin destruction process by alkali hydrolysis which affects glucose production from corn cob as lignocellulose biomass was investigated. Alkali hydrolysis called delignification was performed at 55oC for 4 hr with various NaOH concentrations: 5%, 10% and 15%-wt. It was found that optimal NaOH concentration for lignin reduction was 15%-wt and the percentage of reduction was 89.3%. The untreated and NaOH 15%-wt treated solid fraction were hydrolyzed by 0.75%-wt H2SO4 with various times and temperatures. The glucose content of liquid fraction from hydrolysis was analyzed. The result showed that the yield of glucose for NaOH 15% -wt treated corn cob was higher than that of untreated corn cob for various temperatures and operation times. It implied the destruction of lignin structure would enhance the reactivity of acid catalyst for diluted acid hydrolysis process.

Alkali-aided enzymatic viscosity reduction of sugar beet mash for novel bioethanol production process

International Nuclear Information System (INIS)

Srichuwong, Sathaporn; Arakane, Mitsuhiro; Fujiwara, Maki; Zhang, Zilian; Takahashi, Hiroyuki; Tokuyasu, Ken

2010-01-01

Ethanol fermentation of fresh sugar beet mash (SBM) could give a benefit on reducing energy input for sugar diffusion, juice separation, and water evaporation as used in conventional practices, thus offering promise as a low energy process. Actions of cell-wall degrading enzymes provide a mash with low viscosity, which can be easily fermented to ethanol. However, a several-fold higher enzyme loading was required for viscosity reduction of SBM compared with that of potato mash. In this study, the use of dilute alkali treatment (0.025-0.15 N NaOH, 25 o C, 1 h) in enhancing enzymatic viscosity reduction of SBM was evaluated. The results showed that higher NaOH concentration enhanced demethylation and deacetylation of SBM, resulting in greater performances of the enzymes on reducing viscosity. Efficient enzymatic viscosity reduction of SBM was observed with the 0.1 N NaOH treatment. On the other hand, untreated SBM was highly resistant to viscosity reduction, even though a 20-fold more enzyme loading was used. The resulting mash containing 12-13% (w/v) sucrose yielded 7-8% (v/v) ethanol after 24 h of fermentation (90% efficiency). Accordingly, alkali treatment can be applied for facilitating the use of fresh sugar beet for ethanol production.

PENGARUH PROSES DELIGNIFIKASI PADA PRODUKSI GLUKOSA DARI TONGKOL JAGUNG DENGAN HIDROLISIS ASAM ENCER

OpenAIRE

Primata Mardina; Adelina I. Talalangi; Jhon F. M. Sitinjak; M. Reza Fahrizal; Andri Nugroho

2013-01-01

The dilute acid hydrolysis of corn cob for glucose production has faced barrier because of lignin. In this research, an effective lignin destruction process by alkali hydrolysis which affects glucose production from corn cob as lignocellulose biomass was investigated. Alkali hydrolysis called delignification was performed at 55oC for 4 hr with various NaOH concentrations: 5%, 10% and 15%-wt. It was found that optimal NaOH concentration for lignin reduction was 15%-wt and the percentage of red...

Introducing AAA-MS, a rapid and sensitive method for amino acid analysis using isotope dilution and high-resolution mass spectrometry.

Science.gov (United States)

Louwagie, Mathilde; Kieffer-Jaquinod, Sylvie; Dupierris, Véronique; Couté, Yohann; Bruley, Christophe; Garin, Jérôme; Dupuis, Alain; Jaquinod, Michel; Brun, Virginie

2012-07-06

Accurate quantification of pure peptides and proteins is essential for biotechnology, clinical chemistry, proteomics, and systems biology. The reference method to quantify peptides and proteins is amino acid analysis (AAA). This consists of an acidic hydrolysis followed by chromatographic separation and spectrophotometric detection of amino acids. Although widely used, this method displays some limitations, in particular the need for large amounts of starting material. Driven by the need to quantify isotope-dilution standards used for absolute quantitative proteomics, particularly stable isotope-labeled (SIL) peptides and PSAQ proteins, we developed a new AAA assay (AAA-MS). This method requires neither derivatization nor chromatographic separation of amino acids. It is based on rapid microwave-assisted acidic hydrolysis followed by high-resolution mass spectrometry analysis of amino acids. Quantification is performed by comparing MS signals from labeled amino acids (SIL peptide- and PSAQ-derived) with those of unlabeled amino acids originating from co-hydrolyzed NIST standard reference materials. For both SIL peptides and PSAQ standards, AAA-MS quantification results were consistent with classical AAA measurements. Compared to AAA assay, AAA-MS was much faster and was 100-fold more sensitive for peptide and protein quantification. Finally, thanks to the development of a labeled protein standard, we also extended AAA-MS analysis to the quantification of unlabeled proteins.

EPR and UV/VIS spectroscopic investigations of VO2+ complexes and compounds formed in alkali pyrosulfates

DEFF Research Database (Denmark)

Rasmussen, Søren Birk; Eriksen, Kim Michael; Fehrmann, Rasmus

2002-01-01

The catalytically important molten salt-gas system M2S2O7-M2SO4-V2O5/SO2(g) (M = Na. K, Rb, Cs) has been investigated by X- and Q-band EPR spectroscopy. In order to obtain information about the V(IV) complex formation in the melts, samples rather dilute in V2O5 were quenched from the molten state...... at 450-460degreesC to 0degreesC. EPR spectra of the quenched samples were recorded on samples with alkali to vanadium (M/V) ratios 40, 80 and 160. The spectra show that two V(IV) complexes dominate in the melt regardless of the type of alkali metal ion. In systems with low activity of sulfate...... a paramagnetic V(IV) complex with g(parallel to) = 1.915, g(perpendicular to) = 1,978 and line widths 5-15 Gauss is observed. In systems saturated with M2SO4 the obtained EPR spectra show a paramagnetic complex with the g-tensors g(parallel to) = 1.930, g(perpendicular to) = 1.980 and line widths 20-60 Gauss...

Enthalpic pairwise self-association of L-carnitine in aqueous solutions of some alkali halides at T = 298.15 K

International Nuclear Information System (INIS)

Wang, Hua-Qin; Cheng, Wei-Na; Zhu, Li-Yuan; Hu, Xin-Gen

2016-01-01

Highlights: • Dilution enthalpies of L-carnitine in aqueous alkali halide solutions by ITC. • The second virial coefficients of enthalpy (h_2) have been calculated. • The values of h_2 increase with increasing molalities of aqueous salt solutions. • The signs of h_2 turn from negative in pure water to positive in salt solutions. • The trends is ascribed to the salt effects on pairwise self-associations. - Abstract: Knowledge of the influence of ions of various nature on intermolecular hydrophilic and hydrophobic interactions in solutions is required in many research fields. In this paper, dilution enthalpies of zwitterion L-carnitine in aqueous NaCl, KCl and NaBr solutions of various molalities (b = 0 to 3.0 mol · kg"−"1) have been determined respectively at T = (298.15 ± 0.01) K and p = (0.100 ± 0.005) MPa by isothermal titration calorimetry (ITC). In light of the MacMillan–Mayer theory, the 2nd virial enthalpic coefficients (h_2) have been calculated. The h_2 coefficients increase gradually with increasing molality (b) of the three aqueous alkali halides solutions, from small negative values in pure water to relatively larger positive values in solution. The trends of h_2 coefficients are ascribed to the salt effects on the balance between hydrophilic and hydrophobic interactions in pairwise self-associations. It is considered that the size of cations and anions exert influences on h_2 coefficients through their surface charge densities and hydration (or dehydration) abilities.

Vibrations of alkali metal overlayers on metal surfaces

International Nuclear Information System (INIS)

Rusina, G G; Eremeev, S V; Borisova, S D; Echenique, P M; Chulkov, E V; Benedek, G

2008-01-01

We review the current progress in the understanding of vibrations of alkalis adsorbed on metal surfaces. The analysis of alkali vibrations was made on the basis of available theoretical and experimental results. We also include in this discussion our recent calculations of vibrations in K/Pt(111) and Li(Na)/Cu(001) systems. The dependence of alkali adlayer localized modes on atomic mass, adsorption position and coverage as well as the dependence of vertical vibration frequency on the substrate orientation is discussed. The square root of atomic mass dependence of the vertical vibration energy has been confirmed by using computational data for alkalis on the Al(111) and Cu(001) substrates. We have confirmed that in a wide range of submonolayer coverages the stretch mode energy remains nearly constant while the energy of in-plane polarized modes increases with the increase of alkali coverage. It was shown that the spectrum of both stretch and in-plane vibrations can be very sensitive to the adsorption position of alkali atoms and substrate orientation

Kinetic and Modeling Investigation to Provide Design Guidelines for the NREL Dilute-Acid Process Aimed at Total Hydrolysis/Fractionation of Lignocellulosic Biomass: July 1998

Energy Technology Data Exchange (ETDEWEB)

Lee, Y. Y.; Iyer, P.; Xiang, Q.; Hayes, J.

2004-08-01

Following up on previous work, subcontractor investigated three aspects of using NREL ''pretreatment'' technology for total hydrolysis (cellulose as well as hemicellulose) of biomass. Whereas historic hydrolysis of biomass used either dilute acid or concentrated acid technology for hydrolysis of both hemicellulose and cellulose, NREL has been pursuing very dilute acid hydrolysis of hemicellulose followed by enzymatic hydrolysis of cellulose. NREL's countercurrent shrinking-bed reactor design for hemicellulose hydrolysis (pretreatment) has, however, shown promise for total hydrolysis. For the first task, subcontractor developed a mathematical model of the countercurrent shrinking bed reactor operation and, using yellow poplar sawdust as a feedstock, analyzed the effect of: initial solid feeding rate, temperature, acid concentration, acid flow rate, Peclet number (a measure of backmixing in liquid flow), and bed shrinking. For the second task, subcontractor used laboratory trials, with yellow poplar sawdust and 0.07 wt% sulfuric acid at various temperatures, to verify the hydrolysis of cellulose to glucose (desired) and decomposition of glucose (undesired) and determine appropriate parameters for use in kinetic models. Unlike cellulose and hemicellulose, lignins, the third major component of biomass, are not carbohydrates that can be broken down into component sugars. They are, however, aromatic complex amorphous phenolic polymers that can likely be converted into low-molecular weight compounds suitable for production of fuels and chemicals. Oxidative degradation is one pathway for such conversion and hydrogen peroxide would be an attractive reagent for this, as it would leave no residuals. For the third task, subcontractor reacted lignin with hydrogen peroxide under various conditions and analyzed the resulting product mix.

Alkali aggregate reactivity in concrete structures in western Canada

International Nuclear Information System (INIS)

Morgan, D.R.; Empey, D.

1989-01-01

In several regions of Canada, particularly parts of Ontario, Quebec and the Maritime Provinces, research, testing and evaluation of aged concrete structures in the field has shown that alkali aggregate reactivity can give rise to pronounced concrete deterioration, particularly in hydraulic structures subjected to saturation or alternate wetting and drying such as locks, dams, canals, etc. Concrete deterioration is mainly caused by alkali-silica reactions and alkali-carbonate reactions, but a third type of deterioration involves slow/late expanding alkali-silicate/silica reactivity. The alkalies NaOH and KOH in the concrete pore solutions are mainly responsible for attack on expansive rocks and minerals in concrete. Methods for evaluating alkali-aggregate reaction potential in aggregates, and field and laboratory methods for detecting deterioration are discussed. Examples of alkali-aggregate reactions in structures is western Canada are detailed, including a water reservoir at Canadian Forces Base Chilliwack in British Columbia, the Oldman River diversion and flume, the Lundbreck Falls Bridge, and the St Mary's Reservoir spillway, all in southern Alberta. Mitigative measures include avoidance of use of suspect aggregates, but if this cannot be avoided it is recommended to keep the total alkalies in the concrete as low as possible and minimize opportunities for saturation of concrete by moisture. 16 refs., 19 figs., 1 tab

Degradation of chitosan hydrogel dispersed in dilute carboxylic acids by solution plasma and evaluation of anticancer activity of degraded products

Science.gov (United States)

Chokradjaroen, Chayanaphat; Rujiravanit, Ratana; Theeramunkong, Sewan; Saito, Nagahiro

2018-01-01

Chitosan is a polysaccharide that has been extensively studied in the field of biomedicine, especially its water-soluble degraded products called chitooligosaccharides (COS). In this study, COS were produced by the degradation of chitosan hydrogel dispersed in a dilute solution (i.e., 1.55 mM) of various kinds of carboxylic acids using a non-thermal plasma technology called solution plasma (SP). The degradation rates of chitosan were influenced by the type of carboxylic acids, depending on the interaction between chitosan and each carboxylic acid. After SP treatment, the water-soluble degraded products containing COS could be easily separated from the water-insoluble residue of chitosan hydrogel by centrifugation. The production yields of the COS were mostly higher than 55%. Furthermore, the obtained COS products were evaluated for their inhibitory effect as well as their selectivity against human lung cancer cells (H460) and human lung normal cells (MRC-5).

Spectroscopic analysis of hot-water- and dilute-acid-extracted hardwood and softwood chips

Science.gov (United States)

Lehto, Joni; Louhelainen, Jarmo; Huttunen, Marko; Alén, Raimo

2017-09-01

Hot-water and dilute sulfuric acid pretreatments were performed prior to chemical pulping for silver/white birch (Betula pendula/B. pubescens) and Scots pine (Pinus sylvestris) chips to determine if varying pretreatment conditions on the original wood material were detectable via attenuated total reflectance (ATR) infrared spectroscopy. Pretreatment conditions varied with respect to temperature (130 °C and 150 °C) and treatment time (from 30 min to 120 min). The effects of the pretreatments on the composition of wood chips were determined by ATR infrared spectroscopy. The spectral data were compared to those determined by common wood chemistry analyses to evaluate the suitability of ATR spectroscopy method for rapid detection of changes in the wood chemical composition caused by different pretreatment conditions. In addition to determining wood species-dependent differences in the wood chemical composition, analytical results indicated that most essential lignin- and carbohydrates-related phenomena taking place during hot-water and acidic pretreatments could be described by applying this simple spectral method requiring only a small sample amount and sample preparation. Such information included, for example, the cleavage of essential lignin bonds (i.e., mainly β-O-4 linkages in guaiacyl and syringyl lignin) and formation of newly condensed lignin structures under different pretreatment conditions. Carbohydrate analyses indicated significant removal of hemicelluloses (especially hardwood xylan) and hemicelluloses-derived acetyl groups during the pretreatments, but they also confirmed the highly resistant nature of cellulose towards mild pretreatments.

40 CFR 721.8900 - Substituted halogenated pyridinol, alkali salt.

Science.gov (United States)

2010-07-01

..., alkali salt. 721.8900 Section 721.8900 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.8900 Substituted halogenated pyridinol, alkali salt. (a) Chemical... as substituted halogenated pyridinols, alkali salts (PMNs P-88-1271 and P-88-1272) are subject to...

Alkali-activated blast furnace slag-zeolite cements and concretes

International Nuclear Information System (INIS)

Rakhimov, R.; Rakhimova, N.

2012-01-01

The aim of this work has been the study of alkali-activated slag-zeolite cements and concretes based on them. Various compositions have been tested and some characteristics such as the compressive strength have been measured versus zeolite additions. A table lists the specific surface area and particle size distributions of different cements. The conclusions of the study are the following. First, alkali-activated slag cements and concretes based on them are effective for immobilization of radioactive wastes and the production of building structures, designed for high radiation load. Secondly, zeolite-containing mineral additions are able to increase the immobilization capacity and radiation resistance of alkali-activated blast furnace slag cements and concretes. Thirdly, the efficiency of different zeolite-containing additions - 10% to increase alkali-activated blast furnace slag-zeolite cement strength was established. It is with alkaline components of water-glass, sodium carbonate, sodium sulphate. Fourth, the effective way of introducing zeolite additions in alkali-activated blast furnace slag-zeolite cement is inter-grinding of the slag and addition. Increase in strength of alkali-activated blast furnace slag-zeolite cement stone is 40% higher than that of the stone of a mixture of separately milled components. Fifth, Alkali-activated blast furnace slag-zeolite cements with zeolite-containing additions with a compressive strength of 10.1 to 140 MPa; alkali-activated blast furnace slag-zeolite cements mortars with compressive strength from 35.2 to 97.7 MPa; alkali-activated blast furnace slag-zeolite cements concretes with compressive strength up to 84.5 MPa and frost resistant up to 800 cycles were obtained

Measurement of acid dissociation constants of weak acids by cation exchange and conductometry

Energy Technology Data Exchange (ETDEWEB)

Dasgupta, P.K.; Nara, Osamu (Texas Tech Univ., Lubbock (USA))

1990-06-01

A simple strategy is presented for the determination of acid dissociation constants based on the measurement of conductance of a known concentration of the acid and/or the conductance of a solution of its fully or partially neutralized alkali-metal salts. For an n-protic acid, 2n conductance measurements are minimally necessary. In the simplest case of a typical monoprotic acid, the conductance of its alkali salt solution is measured before and after passage through an H{sup +}-form exchanger. From these data both the pK{sub a} of the acid and the equivalent conductance of the anion can be computed. The underlying equations are rigorously solved for monoprotic acids and some diprotic acid systems. For other diprotic and multiprotic acid systems, initial estimates are obtained by making approximations; the complete data set is then subjected to multiparametric fitting. The method does not require pH measurements; conductance can generally be measured accurately at low enough ionic strengths to obviate the need for major activity correction. Several experimental measurements are presented and excellent agreement with literature pK{sub a} values is observed. The reliability of the equivalent conductance values computed in this fashion is limited, however.

Diglycolic acid modified zirconium phosphate and studies on the extraction of Am(III) and Eu(III) from dilute nitric acid medium

Energy Technology Data Exchange (ETDEWEB)

Selvan, B. Robert; Suneesh, A.S.; Venkatesan, K.A.; Antony, M.P. [Indira Gandhi Centre for Atomic Research, Kalpakkam (India). Fuel Chemistry Division; Dasthaiah, K.; Gardas, R.L. [Indian Institute of Technology - Madras, Chennai (India). Dept. of Chemistry

2017-06-01

Diglycolic acid modified zirconium phosphate (ZrP-DGA) was prepared and studied for the extraction of Am(III) and Eu(III) from dilute nitric acid medium. The distribution coefficient (K{sub d}, mL.g{sup -1}) of Am(III) and Eu(III) was measured as a function of time, pH and concentration of Eu(III) ion etc. The K{sub d} of Am(III) and Eu(III) increased with increase of pH, reached a maximum value of distribution coefficient at pH 1.5 - 2, followed by decrease in K{sub d} values. Rapid extraction of Am(III) and Eu(III) in ZrP-DGA was observed followed by the establishment of equilibrium occurred in 100 min. Kinetics of extraction was fitted in to pseudo second order rate equation. The amount of Eu(III) loaded in ZrP-DGA increased with increase in the concentration of Eu(III) ion in aqueous phase and the isotherm was fitted in to Langmuir and Freundlich adsorption models. The extraction of Am(III) in ZrP-DGA was higher as compared to Eu(III) and the interference of Eu(III) on the extraction of Am(III) was studied. The distribution coefficient of some lanthanides in ZrP-DGA was measured and the K{sub d} of lanthanides increased across the lanthanide series. The extracted trivalent metal ions were recovered in three contacts of loaded ZrP-DGA with 0.5 M nitric acid.

Quantitation of 5-Methyltetrahydrofolic Acid in Dried Blood Spots and Dried Plasma Spots by Stable Isotope Dilution Assays.

Directory of Open Access Journals (Sweden)

Markus Kopp

Full Text Available Because of minimal data available on folate analysis in dried matrix spots (DMSs, we combined the advantages of stable isotope dilution assays followed by LC-MS/MS analysis with DMS sampling to develop a reliable method for the quantitation of plasma 5-methyltetrahydrofolic acid in dried blood spots (DBSs and dried plasma spots (DPSs as well as for the quantitation of whole blood 5-methyltetrahydrofolic acid in DBSs. We focused on two diagnostically conclusive parameters exhibited by the plasma and whole blood 5-methyltetrahydrofolic acid levels that reflect both temporary and long-term folate status. The method is performed using the [2H4]-labeled isotopologue of the vitamin as the internal standard, and three steps are required for the extraction procedure. Elution of the punched out matrix spots was performed using stabilization buffer including Triton X-100 in a standardized ultrasonication treatment followed by enzymatic digestion (whole blood only and solid-phase extraction with SAX cartridges. This method is sensitive enough to quantify 27 nmol/L whole blood 5-methyltetrahydrofolic acid in DBSs and 6.3 and 4.4 nmol/L plasma 5-methyltetrahydrofolic acid in DBSs and DPSs, respectively. The unprecedented accurate quantification of plasma 5-methyltetrahydrofolic acid in DBSs was achieved by thermal treatment prior to ultrasonication, inhibiting plasma conjugase activity. Mass screenings are more feasible and easier to facilitate for this method in terms of sample collection and storage compared with conventional clinical sampling for the assessment of folate status.

Alkali elemental and potassium isotopic compositions of Semarkona chondrules

Science.gov (United States)

Alexander, C.M. O'D.; Grossman, J.N.

2005-01-01

We report measurements of K isotope ratios in 28 Semarkona chondrules with a wide range of petrologic types and bulk compositions as well as the compositions of CPX-mesostasis pairs in 17 type I Semarkona chondrules, including two chondrules with radial alkali zonation and 19 type II chondrules. Despite the wide range in K/Al ratios, no systematic variations in K isotopic compositions were found. Semarkona chondrules do not record a simple history of Rayleigh-type loss of K. Experimentally determined evaporation rates suggest that considerable alkali evaporation would have occurred during chondrule formation. Nevertheless, based on Na CPX-mesostasis distribution coefficients, the alkali contents of the cores of most chondrules in Semarkona were probably established at the time of final crystallization. However, Na CPX-mesostasis distribution coefficients also show that alkali zonation in type I Semarkona chondrules was produced by entry of alkalis after solidification, probably during parent body alteration. This alkali metasomatism may have gone to completion in some chondrules. Our preferred explanation for the lack of systematic isotopic enrichments, even in alkali depleted type I chondrule cores, is that they exchanged with the ambient gas as they cooled. ?? The Meteoritical Society, 2005.

Rapid and precise measurement of serum branched-chain and aromatic amino acids by isotope dilution liquid chromatography tandem mass spectrometry.

Directory of Open Access Journals (Sweden)

Ruiyue Yang

Full Text Available BACKGROUND: Serum branched-chain and aromatic amino acids (BCAAs and AAAs have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming. METHODS: An isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS method for serum BCAAs and AAAs was developed. The serum was mixed with isotope-labeled BCAA and AAA internal standards and the amino acids were extracted with acetonitrile, followed by analysis using LC/MS/MS. The LC separation was performed on a reversed-phase C18 column, and the MS/MS detection was performed via the positive electronic spray ionization in multiple reaction monitoring mode. RESULTS: Specific analysis of the amino acids was achieved within 2 min. Intra-run and total CVs for the amino acids were less than 2% and 4%, respectively, and the analytical recoveries ranged from 99.6 to 103.6%. CONCLUSION: A rapid and precise method for the measurement of serum BCAAs and AAAs was developed and may serve as a quick tool for screening serum BCAAs and AAAs in studies assessing diabetes risk.

40 CFR 721.1878 - Alkali metal alkyl borohydride (generic).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal alkyl borohydride... Specific Chemical Substances § 721.1878 Alkali metal alkyl borohydride (generic). (a) Chemical substance... alkali metal alkyl borohydride (PMN P-00-1089) is subject to reporting under this section for the...

Concrete alkali-silica reaction and nuclear radiation damage

International Nuclear Information System (INIS)

Ichikawa, Tsuneki

2008-01-01

The deterioration of concrete by alkali-silica reaction of aggregates (ASR) and the effect of nuclear radiations on the ASR have been reviewed based on our studies on the mechanism of ASR and the effect of nuclear radiations on the resistivity of minerals to alkaline solution. It has been found that the ASR is initiated by the attack of alkaline solution in concrete to silicious aggregates to convert them into hydrated alkali silicate. The consumption of alkali hydroxide by the aggregates induces the dissolution of Ca 2+ ions into the solution. The alkali silicate surrounding the aggregates then reacts with Ca 2+ ions to convert to insoluble tight and rigid reaction rims. The reaction rim allows the penetration of alkaline solution but prevents the leakage of viscous alkali silicate, so that alkali silicate generated afterward is accumulated in the aggregate to give an expansive pressure enough for cracking the aggregate and the surrounding concrete. The effect of nuclear radiation on the reactivity of quartz and plagioclase, a part of major minerals composing volcanic rocks as popular aggregates, to alkaline solution has been examined for clarifying whether nuclear radiations accelerates the ASR. It has been found that the irradiation of these minerals converts them into alkali-reactive amorphous ones. The radiation dose for plagioclase is as low as 10 8 Gy, which suggests that the ASR of concrete surrounding nuclear reactors is possible to be accelerated by nuclear radiation. (author)

Lower pressure heating steam is practical for the distributed dry dilute sulfuric acid pretreatment.

Science.gov (United States)

Shao, Shuai; Zhang, Jian; Hou, Weiliang; Qureshi, Abdul Sattar; Bao, Jie

2017-08-01

Most studies paid more attention to the pretreatment temperature and the resulted pretreatment efficiency, while ignored the heating media and their scalability to an industry scale. This study aimed to use a relative low pressure heating steam easily provided by steam boiler to meet the requirement of distributed dry dilute acid pretreatment. The results showed that the physical properties of the pretreated corn stover were maintained stable using the steam pressure varying from 1.5, 1.7, 1.9 to 2.1MPa. Enzymatic hydrolysis and high solids loading simultaneous saccharification and fermentation (SSF) results were also satisfying. CFD simulation indicated that the high injection velocity of the low pressure steam resulted in a high steam holdup and made the mixing time of steam and solid corn stover during pretreatment much shorter in comparison with the higher pressure steam. This study provides a design basis for the boiler requirement in distributed pretreatment concept. Copyright © 2017 Elsevier Ltd. All rights reserved.

The utilization of alkali-treated melon husk by broilers.

Science.gov (United States)

Abiola, S S; Amalime, A C; Akadiri, K C

2002-09-01

The effects of alkali treatment on chemical constituents of melon husk (MH) and performance characteristics of broilers fed alkali-treated MH (ATMH) diets were investigated. The chemical analysis showed that alkali treatment increased the ash content of MH (from 15.70% to 16.86%) and reduced the crude fibre content (from 29.00% to 14.00%). Result of feed intake was superior on 30% alkali diet with a value of 100.14 g/bird/day. Body weight gain decreased with increase in the level of ATMH in the diet. Highest dressing percentage of 66.33% and best meat/bone ratio of 2.57 were obtained on 10% and 20% alkali diets, respectively. Dietary treatments had significant effect (P poultry carcases and chicken meat with favourable shelf life.

A coupled channel study on a binding mechanism of positronic alkali atoms

International Nuclear Information System (INIS)

Kubota, Yoshihiro; Kino, Yasushi

2008-01-01

In order to investigate the binding mechanism of weakly bound states of positronic alkali atoms, we calculate the energies and wavefunctions using the Gaussian expansion method (GEM) where a positronium (Ps)-alkali ion channel and a positron-alkali atom channel are explicitly introduced. The energies of the bound states are updated using a model potential that reproduces well the observed energy levels of alkali atoms. The binding mechanism of the positronic alkali atom is analyzed by the wavefunctions obtained. The structure of the positronic alkali atom has been regarded as a Ps cluster orbiting the alkali ion, which is described by the Ps-alkali ion channel. We point out that the fraction having the positron-alkali atom configuration is small but plays an indispensable role for the weakly bound system

IRMPD Action Spectroscopy of Alkali Metal Cation-Cytosine Complexes: Effects of Alkali Metal Cation Size on Gas Phase Conformation

NARCIS (Netherlands)

Yang, B.; Wu, R.R.; Polfer, N.C.; Berden, G.; Oomens, J.; Rodgers, M.T.

2013-01-01

The gas-phase structures of alkali metal cation-cytosine complexes generated by electrospray ionization are probed via infrared multiple photon dissociation (IRMPD) action spectroscopy and theoretical calculations. IRMPD action spectra of five alkali metal cation-cytosine complexes exhibit both

Alkali absorption and citrate excretion in calcium nephrolithiasis

Science.gov (United States)

Sakhaee, K.; Williams, R. H.; Oh, M. S.; Padalino, P.; Adams-Huet, B.; Whitson, P.; Pak, C. Y.

1993-01-01

The role of net gastrointestinal (GI) alkali absorption in the development of hypocitraturia was investigated. The net GI absorption of alkali was estimated from the difference between simple urinary cations (Ca, Mg, Na, and K) and anions (Cl and P). In 131 normal subjects, the 24 h urinary citrate was positively correlated with the net GI absorption of alkali (r = 0.49, p origin of hypocitraturia. However, the normal dependence was maintained in CDS and in idiopathic hypocitraturia, suggesting that reduced citrate excretion was largely dietary in origin as a result of low net alkali absorption (from a probable relative deficiency of vegetables and fruits or a relative excess of animal proteins).

The 4843 Alkali Metal Storage Facility Closure Plan

International Nuclear Information System (INIS)

1991-06-01

The 4843 AMSF has been used primarily to provide a centralized building to receive and store dangerous and mixed alkali metal waste, including sodium and lithium, which has been generated at the Fast Flux Test Facility and at various other Hanford Site operations that used alkali metals. Most of the dangerous and mixed alkali metal waste received consists of retired equipment from liquid sodium processes. The unit continues to store material. In general, only solid alkali metal waste that is water reactive is stored at the 4843 AMSF. The 4843 AMSF will be closed in a manner consistent with Ecology guidelines and regulations (WAC 173-303-610). The general closure procedure is detailed as follows

On-line alkali monitoring - Part 1; Kontinuerlig alkalimaetning - Etapp 1

Energy Technology Data Exchange (ETDEWEB)

Andersson, Christer; Ljung, P; Woxlin, H

1997-02-01

As a consequence of the increased knowledge of the environmental impact of combustion based heat and power generation, the use of renewable biofuels will be increased. An obstacle associated to biofuel combustion compared to other fuels is the large release of alkali. Alkali compounds in flue gases are known to cause severe operational problems. Three of the major problems are; fouling of superheating tubes (causing reduced heat transfer and possibly corrosion), agglomeration of the bed material in fluidized beds, and poisoning of SCR catalysts. Yet another alkali related problem arises when, in order to increase the electric efficiency of combustion power plants, combined-cycle technology is used. Alkali vapour present in the fuel gas for the gas turbine is condensed to particles which increase corrosion and erosion of the turbine blades. The research on ash related operational problems has to be extended in order to ensure future use of biofuels in heat and power generation. In all successful research, adequate tools are necessary. To investigate ash related problems the key issue is to be able to perform continuous alkali measurements. This pilot study has investigated the need of continuous alkali measurements, which alkali species are harmful in the different applications and also available instrumentation capable of measuring the specific alkali species. The report gives a short summary presenting alkali related operational problems. In addition a schematic overview is given, showing the alkali species that possibly can exist in various parts of the power plant. 48 refs, 13 figs, 4 tabs

Salts of alkali metal anions and process of preparing same

Science.gov (United States)

Dye, James L.; Ceraso, Joseph M.; Tehan, Frederick J.; Lok, Mei Tak

1978-01-01

Compounds of alkali metal anion salts of alkali metal cations in bicyclic polyoxadiamines are disclosed. The salts are prepared by contacting an excess of alkali metal with an alkali metal dissolving solution consisting of a bicyclic polyoxadiamine in a suitable solvent, and recovered by precipitation. The salts have a gold-color crystalline appearance and are stable in a vacuum at -10.degree. C. and below.

Two-phase alkali-metal experiments in reduced gravity

International Nuclear Information System (INIS)

Antoniak, Z.I.

1986-06-01

Future space missions envision the use of large nuclear reactors utilizing either a single or a two-phase alkali-metal working fluid. The design and analysis of such reactors require state-of-the-art computer codes that can properly treat alkali-metal flow and heat transfer in a reduced-gravity environment. A literature search of relevant experiments in reduced gravity is reported on here, and reveals a paucity of data for such correlations. The few ongoing experiments in reduced gravity are noted. General plans are put forth for the reduced-gravity experiments which will have to be performed, at NASA facilities, with benign fluids. A similar situation exists regarding two-phase alkali-metal flow and heat transfer, even in normal gravity. Existing data are conflicting and indequate for the task of modeling a space reactor using a two-phase alkali-metal coolant. The major features of past experiments are described here. Data from the reduced-gravity experiments with innocuous fluids are to be combined with normal gravity data from the two-phase alkali-metal experiments. Analyses undertaken here give every expectation that the correlations developed from this data base will provide a valid representation of alkali-metal heat transfer and pressure drop in reduced gravity

High alkali-resistant basalt fiber for reinforcing concrete

International Nuclear Information System (INIS)

Lipatov, Ya.V.; Gutnikov, S.I.; Manylov, M.S.; Zhukovskaya, E.S.; Lazoryak, B.I.

2015-01-01

Highlights: • Doping of basalt fiber with ZrSiO 4 increased its alkali resistance. • Alkali treatment results in formation of protective surface layer on fibers. • Morphology and chemical composition of surface layer were investigated. • Mechanical properties of fibers were analyzed by a Weibull distribution. • Zirconia doped basalt fibers demonstrate high performance in concrete. - Abstract: Basalt glasses and fibers with zirconia content in the range from 0 to 7 wt% were obtained using ZrSiO 4 as a zirconium source. Weight loss and tensile strength loss of fibers after refluxing in alkali solution were determined. Basalt fiber with 5.7 wt% ZrO 2 had the best alkali resistance properties. Alkali treatment results in formation of protective surface layer on fibers. Morphology and chemical composition of surface layer were investigated. It was shown that alkali resistance of zirconia doped basalt fibers is caused by insoluble compounds of Zr 4+ , Fe 3+ and Mg 2+ in corrosion layer. Mechanical properties of initial and leached fibers were evaluated by a Weibull distribution. The properties of basalt fibers with ZrSiO 4 were compared with AR-glass fibers. The performance of concrete with obtained fibers was investigated

Determination of free nitric acid in uranyl nitrate solution

International Nuclear Information System (INIS)

Mayankutty, P.C.; Ravi, S.; Nadkarni, M.N.

1981-01-01

Potentiometric titration of uranyl nitrate solution with sodium hydroxide exhibits two peaks. The first peak characterises the following reaction, UO 2 (C 2 O 4 )+NaOH Na[UO 2 (C 2 O 4 )(OH)]. This reaction, indicating the partial hydrolysis of uranyl oxalate complex, appears to be complete at pH9. If the titration is carried out to this end-point pH, the total alkali consumed can be equated to the sum of uranium content and the free acidity present in the sample volume. Based on this, a method was standardised to determine the free acidity in uranyl nitrate solution. The sample, taken in a solution of potassium oxalate previously adjusted to pH9, is titrated to this pH with standard sodium hydroxide. The free acidity in the sample can be computed by subtracting the alkali reacted with uranium from the total alkali consumed. Analyses of several synthetic samples containing uranium and nitric acid in a wide range of combinations indicate that the free acidity can be accurately determined by this method, if uranium concentration in the sample is known. The results are compared to those obtained by two other widely used methods, viz., (i) titration of pH7 in the presence of neutral potassium oxalate to suppress hydrolysis and (ii) separation of hydrolyzable ions on a cationic resin and alkali titration of the free acid released. The advantages of and the precision obtained with the present method over the above two methods are discussed. (author)

Preferential Treatment: Interaction Between Amino Acids and Minerals

Science.gov (United States)

Crapster-Pregont, E. J.; Cleaves, H. J.; Hazen, R. M.

2008-12-01

Amino acids are the building blocks of proteins and are important for some models of the origin of life. Polymerization of amino acids from dilute solution is unlikely without a scaffold or catalyst. The surfaces of early Earth minerals are the most likely candidates for this role. The surface adsorption behavior of 12 amino acids (L-alanine, L-serine, L-aspartic acid, L-proline, L- phenylalanine, L-valine, L-arginine, d-amino valeric acid, glycine, L-lysine, L-isoleucine, and B-alanine) on 21 minerals (quartz, calcite, enstatite, illite, olivine, pyrrhotite, pyrite, alkali basalt, albite, analcime, chlorite, barite, hydroxyl apatite, hematite, magnetite, aluminum hydroxide, kaolin, silica gel, corundum, rutile, and montmorillonite) was determined via batch adsorption experiments. Absorption was determined for concentrations between 10-4M and 10-6M in the presence of 0.1M NaCl, and between pH values of 3 and 9 at 25 degrees C. The equilibrated solutions were centrifuged, filtered, derivatized using a fluorescent amino group tag (dansyl-chloride) and analyzed by HPLC. Adsorption was standardized using BET surface area measurements for each mineral to give the number of mols of each amino acid adsorbed per square meter for each mineral. The results indicate an enormous difference in the adsorption of amino acids between minerals, along with major differences in the adsorption of individual amino acids on the same mineral surface. There is also a change in the absorbance of amino acids as the pH changes. Many previous studies of amino acid concentration and catalysis by minerals have used clay minerals because of their high surface areas, however, this data suggests that the surfaces of minerals such as calcite, quartz and pyrite have even higher affinities for amino acids. The results suggest mineral surfaces that could be optimal locations for the polymerization of molecules linked to the origin of life.

Muonium centers in the alkali halides

International Nuclear Information System (INIS)

Baumeler, H.; Kiefl, R.F.; Keller, H.; Kuendig, W.; Odermatt, W.; Patterson, B.D.; Schneider, J.W.; Savic, I.M.

1986-01-01

Muonium centers (Mu) in single crystals and powdered alkali halides have been studied using the high-timing-resolution transverse field μSR technique. Mu has been observed and its hyperfine parameter (HF) determined in every alkali halide. For the rocksalt alkali halides, the HF parameter A μ shows a systematic dependence on the host lattice constant. A comparison of the Mu HF parameter with hydrogen ESR data suggests that the Mu center is the muonic analogue of the interstitial hydrogen H i 0 -center. The rate of Mu diffusion can be deduced from the motional narrowing of the nuclear hyperfine interaction. KBr shows two different Mu states, a low-temperature Mu I -state and a high-temperature Mu II -state. (orig.)

Upgrading platform using alkali metals

Science.gov (United States)

Gordon, John Howard

2014-09-09

A process for removing sulfur, nitrogen or metals from an oil feedstock (such as heavy oil, bitumen, shale oil, etc.) The method involves reacting the oil feedstock with an alkali metal and a radical capping substance. The alkali metal reacts with the metal, sulfur or nitrogen content to form one or more inorganic products and the radical capping substance reacts with the carbon and hydrogen content to form a hydrocarbon phase. The inorganic products may then be separated out from the hydrocarbon phase.

Comparison of isotope dilution and excretion methods for determining the half-life of ascorbic acid in the guinea pig

International Nuclear Information System (INIS)

Kipp, D.E.; Rivers, J.M.

1984-01-01

The half-life of ascorbic acid (AA) in guinea pigs was investigated by the isotope dilution and excretion methods. The dilution method measures [1-14C]AA disappearance from the plasma, whereas the excretion method measures the elimination of [1-14C]AA and the metabolites from the body. Two groups of animals underwent both isotope studies in reverse order. Animals were conditioned to the experimental procedures and fed 2.5 mg AA/100 g body weight orally to maintain a daily intake of the vitamin independent of food consumption. The two isotope procedures imposed similar stress on the animals, as determined by plasma cortisol levels and body weight changes. The AA half-life calculations of the rapidly exchangeable pool by the isotope dilution method yielded values of 1.23 and 0.34 hours for the two groups, respectively. The half-life of the slowly exchangeable pool for the two groups was 60.2 and 65.8 hours, respectively. The half-life of AA in the rapidly exchangeable pool, as measured by the excretion studies, was 4.57-8.75 hours. For the slowly exchangeable pool, it was 146-149 hours. The longer half-life of both pools obtained with the excretion method indicates that the isotope is disappearing from the plasma more rapidly than it is being excreted. This suggests that a portion of the [1-14C]AA leaving the plasma is removed to a body pool that is not sampled by the isotope excretion method

Alkali-slag cements for the immobilization of radioactive wastes

International Nuclear Information System (INIS)

Shi, C.; Day, R.L.

1996-01-01

Alkali-slag cements consist of glassy slag and an alkaline activator and can show both higher early and later strengths than Type III Portland cement, if a proper alkaline activator is used. An examination of microstructure of hardened alkali-slag cement pastes with the help of XRD and SEM with EDAX shows that the main hydration product is C-S-H (B) with low C/S ratio and no crystalline substances exist such as Ca(OH) 2 , Al (OH) 3 and sulphoaluminates. Mercury intrusion tests indicate that hardened alkali-slag cement pastes have a lower porosity than ordinary Portland cement, and contain mainly gel pores. The fine pore structure of hardened alkali-slag cement pastes will restrict the ingress of deleterious substances and the leaching of harmful species such as radionuclides. The leachability of Cs + from hardened alkali-slag cement pastes is only half of that from hardened Portland cement. From all these aspects, it is concluded that alkali-slag cements are a better solidification matrix than Portland cement for radioactive wastes

Process Design and Economics for the Conversion of Lignocellulosic Biomass to Hydrocarbons: Dilute-Acid and Enzymatic Deconstruction of Biomass to Sugars and Biological Conversion of Sugars to Hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Davis, R.; Tao, L.; Tan, E. C. D.; Biddy, M. J.; Beckham, G. T.; Scarlata, C.; Jacobson, J.; Cafferty, K.; Ross, J.; Lukas, J.; Knorr, D.; Schoen, P.

2013-10-01

This report describes one potential conversion process to hydrocarbon products by way of biological conversion of lingnocellulosic-dervied sugars. The process design converts biomass to a hydrocarbon intermediate, a free fatty acid, using dilute-acid pretreatement, enzymatic saccharification, and bioconversion. Ancillary areas--feed handling, hydrolysate conditioning, product recovery and upgrading (hydrotreating) to a final blendstock material, wastewater treatment, lignin combusion, and utilities--are also included in the design.

Saccharification of gamma-ray and alkali pretreated lignocellulosics

International Nuclear Information System (INIS)

Begum, A.; Choudhury, N.

1988-01-01

Enzymic saccharification of gamma ray and alkali pretreated sawdust, rice straw, and sugar cane bagasse showed higher release of reducing sugar from pretreated substrates. By gamma ray treatment alone (500 kGy) reducing sugar release of 2.8, 9.2, and 10 g/l was obtained from 7.5% (w/v) sawdust, rice straw, and bagasse and the same substrates showed reducing sugar release of 4.2, 30, and 20 g/l respectively when treated with alkali (0.1 g/g). Combination of gamma ray with alkali treatment further increased the reducing sugar release to 10.2, 33, and 36 g/l from sawdust, rice straw, and bagasse respectively. The effects of gamma ray and alkali treatment on saccharification varied with the nature of the substrate

Effect of low severity dilute-acid pretreatment of barley straw and decreased enzyme loading hydrolysis on the production of fermentable substrates and the release of inhibitory compounds

NARCIS (Netherlands)

Panagiotopoulos, I.A.; Lignos, G.D.; Bakker, R.R.C.; Koukios, E.G.

2012-01-01

The objective of this work was to investigate the feasibility of combining low severity dilute-acid pretreatment of barley straw and decreased enzyme loading hydrolysis for the high production of fermentable substrates and the low release of inhibitory compounds. For most of the pretreatments at 160

Complexes in polyvalent metal - Alkali halide melts

International Nuclear Information System (INIS)

Akdeniz, Z.; Tosi, M.P.

1991-03-01

Experimental evidence is available in the literature on the local coordination of divalent and trivalent metal ions by halogens in some 140 liquid mixtures of their halides with alkali halides. After brief reference to classification criteria for main types of local coordination, we focus on statistical mechanical models that we are developing for Al-alkali halide mixtures. Specifically, we discuss theoretically the equilibrium between (AlF 6 ) 3- and (AlF 4 ) - complexes in mixtures of AlF 3 and NaF as a function of composition in the NaF-rich region, the effect of the alkali counterion on this equilibrium, the possible role of (AlF 5 ) 2- as an intermediate species in molten cryolite, and the origin of the different complexing behaviours of Al-alkali fluorides and chlorides. We also present a theoretical scenario for processes of structure breaking and electron localization in molten cryolite under addition of sodium metal. (author). 26 refs, 2 tabs

Long term mechanical properties of alkali activated slag

Science.gov (United States)

Zhu, J.; Zheng, W. Z.; Xu, Z. Z.; Leng, Y. F.; Qin, C. Z.

2018-01-01

This article reports a study on the microstructural and long-term mechanical properties of the alkali activated slag up to 180 days, and cement paste is studied as the comparison. The mechanical properties including compressive strength, flexural strength, axis tensile strength and splitting tensile strength are analyzed. The results showed that the alkali activated slag had higher compressive and tensile strength, Slag is activated by potassium silicate (K2SiO3) and sodium hydroxide (NaOH) solutions for attaining silicate modulus of 1 using 12 potassium silicate and 5.35% sodium hydroxide. The volume dosage of water is 35% and 42%. The results indicate that alkali activated slag is a kind of rapid hardening and early strength cementitious material with excellent long-term mechanical properties. Single row of holes block compressive strength, single-hole block compressive strength and standard solid brick compressive strength basically meet engineering requirements. The microstructures of alkali activated slag are studied by X-ray diffraction (XRD). The hydration products of alkali-activated slag are assured as hydrated calcium silicate and hydrated calcium aluminate.

Ternary alkali-metal and transition metal or metalloid acetylides as alkali-metal intercalation electrodes for batteries

Science.gov (United States)

Nemeth, Karoly; Srajer, George; Harkay, Katherine C; Terdik, Joseph Z

2015-02-10

Novel intercalation electrode materials including ternary acetylides of chemical formula: A.sub.nMC.sub.2 where A is alkali or alkaline-earth element; M is transition metal or metalloid element; C.sub.2 is reference to the acetylide ion; n is an integer that is 0, 1, 2, 3 or 4 when A is alkali element and 0, 1, or 2 when A is alkaline-earth element. The alkali elements are Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs) and Francium (Fr). The alkaline-earth elements are Berilium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra). M is a transition metal that is any element in groups 3 through 12 inclusive on the Periodic Table of Elements (elements 21 (Sc) to element 30 (Zn)). In another exemplary embodiment, M is a metalloid element.

Alkali metals and group IIA metals

International Nuclear Information System (INIS)

Fenton, D.E.

1987-01-01

This chapter on the coordination complexes of the alkali metals of group IIA starts with a historical perspective of their chemistry, from simple monodentate ligands, metal-β-diketonates to the macrocyclic polyethers which act as ligands to the alkali and akaline earth metals. Other macrocyclic ligands include quarterenes, calixarenes, porphyrins, phthalocyanines and chlorophylls. A section on the naturally occurring ionophores and carboxylic ionophores is included. (UK)

Mechanical filter for alkali atoms

CERN Document Server

Toporkov, D K

2000-01-01

A device for separating gases of different mass is discussed. Such a device could be used in a laser-driven spin exchange source of polarized hydrogen atoms to reduce the contamination of alkali atoms. A Monte Carlo simulation has shown that the suggested apparatus based on a commercial turbo pump could reduce by a factor of 10-15 the concentration of the alkali-metal atoms in the hydrogen flow from a laser driven polarized source. This would greatly enhance the effective polarization in hydrogen targets.

The influence of alkali promoters on coadsorbed molecules

International Nuclear Information System (INIS)

Umbach, E.

1986-01-01

A model has been suggested recently based on the results of an extensive study of the coadsorbate system CO + K on Ru(001). It is introduced and discussed in this article based on previous results and on results obtained very recently for a similar coadsorbate system, CO + K/Ni(111). This model is in competition with a variety of differing or similar ideas and interpretations which are mostly based on similar experimental results. Some of these other models postulate a lying-down, or strongly tilted, molecule in the presence of alkali atoms, at least at low coverages. The CO molecule is usually considered to be attached to the substrate and to be closely coadsorbed to the alkali neighbor(s) but sometimes even a vertical or horizontal adsorption on top of the alkali layer has been suggested. The interaction between alkali and CO has been described as indirect via the substrate or direct by forming a ''π''-bond between adjacent alkalis and CO molecules or even by forming an ionic K/sub x/-CO/sub y/ complex. Some authors prefer a model in which the main (or exclusive) interaction comes from a charge transfer from the donating alkali into the 2π orbital of the coadsorbed CO, thus, enhancing the C- metal and reducing the C-O bond strength

Alkali-heat treatment of a low modulus biomedical Ti-27Nb alloy

International Nuclear Information System (INIS)

Zhou, Y; Wang, Y B; Zhang, E W; Cheng, Y; Xiong, X L; Zheng, Y F; Wei, S C

2009-01-01

This study focuses on the surface modification of a near β-type Ti-27 wt.% Nb alloy by alkali-heat treatment. The influence of alkali concentration, alkali-treated time and alkali-treated temperature on the microstructure and constitutional phases of the modified surface is investigated by SEM, XRD and ICP. Immersion experiments in a simulated body fluid (SBF) were carried out to examine the Ca-P phase forming ability of the modified surfaces. The SEM observation and XRD analysis revealed that a sodium titanate layer is formed after alkali-heat treatment. The morphology and Ca-P phase forming of the layer are greatly affected by the surface roughness of the samples, the alkali concentration, the alkali-treated time and alkali-treated temperature. The results of SBF immersion, which are obtained by ICP analysis, indicate that the activated sodium titanate layer prepared by alkali-heat treatment is beneficial to further improving the biocompatibility of the Ti-27 wt.% Nb alloy.

An AFM and XPS study of corrosion caused by micro-liquid of dilute sulfuric acid on stainless steel

International Nuclear Information System (INIS)

Wang Rongguang

2004-01-01

Micro-liquid of dilute sulfuric acid deposited on SUS304 steel surface were observed with the ac non-contact mode of an atomic force microscopy (AFM), and the detail of the corrosion process caused by them was investigated with the contact mode of the AFM, X-ray photoelectron spectroscopy (XPS) and wavelength dispersive X-ray spectroscopy (WDXS). As a result, even not applying bias voltages between the tip of the cantilever and the specimen, micro-liquid of sulfuric acid can be successfully imaged using the ac non-contact mode of AFM. Two shapes of micro-acid, i.e., micro-droplets and micro-films, were found to co-exist on the specimen surface. On areas covered by micro-films of acid, only small corrosion product particles appeared and no corrosion pits were found. Beneath micro-droplets, corrosion reaction continue to produce pits until they were all consumed to form a corrosion product (mainly iron oxides) with almost the same shape with the droplet. The total corrosion reaction time was speculated to be between 690 and 1500 ks. The corrosion product formed from micro-droplets was believed to be a process of accumulating small corrosion product particles from the liquid/substrate interface to the surface of the formerly produced corrosion product. The XPS and WDXS analysis also supports the above results

Thermodynamic modelling of alkali-activated slag cements

International Nuclear Information System (INIS)

Myers, Rupert J.; Lothenbach, Barbara; Bernal, Susan A.; Provis, John L.

2015-01-01

Highlights: • A thermodynamic modelling analysis of alkali-activated slag cements is presented. • Thermodynamic database describes zeolites, alkali carbonates, C–(N–)A–S–H gel. • Updated thermodynamic model for Mg–Al layered double hydroxides. • Description of phase assemblages in Na 2 SiO 3 - and Na 2 CO 3 -activated slag cements. • Phase diagrams for NaOH-activated and Na 2 SiO 3 -activated slag cements are simulated. - Abstract: This paper presents a thermodynamic modelling analysis of alkali-activated slag-based cements, which are high performance and potentially low-CO 2 binders relative to Portland cement. The thermodynamic database used here contains a calcium (alkali) aluminosilicate hydrate ideal solid solution model (CNASH-ss), alkali carbonate and zeolite phases, and an ideal solid solution model for a hydrotalcite-like Mg–Al layered double hydroxide phase. Simulated phase diagrams for NaOH- and Na 2 SiO 3 -activated slag-based cements demonstrate the high stability of zeolites and other solid phases in these materials. Thermodynamic modelling provides a good description of the chemical compositions and types of phases formed in Na 2 SiO 3 -activated slag cements over the most relevant bulk chemical composition range for these cements, and the simulated volumetric properties of the cement paste are consistent with previously measured and estimated values. Experimentally determined and simulated solid phase assemblages for Na 2 CO 3 -activated slag cements were also found to be in good agreement. These results can be used to design the chemistry of alkali-activated slag-based cements, to further promote the uptake of this technology and valorisation of metallurgical slags

Mineralization dynamics of metakaolin-based alkali-activated cements

International Nuclear Information System (INIS)

Gevaudan, Juan Pablo; Campbell, Kate M.; Kane, Tyler J.; Shoemaker, Richard K.; Srubar, Wil V.

2017-01-01

This paper investigates the early-age dynamics of mineral formation in metakaolin-based alkali-activated cements. The effects of silica availability and alkali content on mineral formation were investigated via X-ray diffraction and solid-state 29 Si magic-angle spinning nuclear magnetic resonance spectroscopy at 2, 7, 14, and 28 days. Silica availability was controlled by using either liquid- (immediate) or solid-based (gradual) sodium silicate supplements. Mineral (zeolitic) and amorphous microstructural characteristics were correlated with observed changes in bulk physical properties, namely shrinkage, density, and porosity. Results demonstrate that, while alkali content controls the mineralization in immediately available silica systems, alkali content controls the silica availability in gradually available silica systems. Immediate silica availability generally leads to a more favorable mineral formation as demonstrated by correlated improvements in bulk physical properties.

The solvent extraction of alkali metal ions with β-diketones

International Nuclear Information System (INIS)

Munakata, Megumu; Niina, Syozo; Shimoji, Noboru

1974-01-01

This work was undertaken to investigate effects of solvent and chelating-agent on the solvent extraction of alkali metal ions by seven β-diketones, acetylacetone (Acac), benzoylacetone (BzA), dipivaloylmethane (DPM), dibenzoylmethane (DBM), thenoyltrifluoloacetone (TTA), benzoyltrifluoroacetone (BFA) and hexafluoroacetylacetone (HFA), and to separate lithium from alkali metals. The extraction of alkali metals increase with increasing donor power of the solvent: i.e., benzene Na>K>Rb>Cs, which is also the order in which the adduct formation of these β-diketone chelates with donor solvents increase. The adduct formations between β-diketone chelates of alkali metals and donor solvents markedly enhance the solubilities of the chelates in solvents and, consequently, the extractabilities of alkali metals with β-diketones. Lithium was extracted with TTA in ether at such a low base concentration that sodium, potassium, rubidium and cesium were hardly extracted, and this enabled to separate lithium from other metals by the use of rubidium hydroxide (0.02 M). An attempt has been made to isolate alkali metal β-diketone chelates and some chelates have been obtained as crystals. The infrared absorption bands arising from C=O and C.=C of TTA shift to lower frequencies in the alkali metal chelates with TTA, and consequently, β-diketones is suggested to coordinate to alkali metal as a bidentate ligand. (JPN)

Validation of ion chromatography for the determination of transition metal ions along with alkali, alkaline earth metal elements for uranium oxide fuel

International Nuclear Information System (INIS)

Kelkar, Anoop; Prakash, Amrit; Afzal, Mohd.; Panakkal, J.P.

2009-02-01

The present report describes the use of Ion chromatography (IC) methods with spectrophotometric and direct conductivity detection for the determination of transition metal elements and alkali alkaline earth metal ions in UO 2 pellets. Transmet analytical column and Metrosep- cation 1-2 column were used for the separation of transition metal elements and alkali and alkaline earth metal elements respectively. Oxalic acid and mixture of pyridine 2,6-dicarboxylic acid (PDCA), Na 2 SO 4 and NaCl were used as mobile phase for the separation of transition metal ions and monitored after post - column reaction with 4,2-pyridylazo resorcinol (PAR) at 520nm spectrophotometrically. In the determination of alkali and alkaline earth metal ions the interference of transition metals are removed by complexing them with PDCA. Mixture of tartaric acid and PDCA employed in the separation of alkali and alkaline earth metal ions and monitored on direct conductivity detector. Mobile phase composition was optimised for the base line separation. Calibration plots of Fe 3+ , Cu 2+ , Ni 2+ , Co 2+ , Cd 2+ , Mn 2+ , Li + , Na + , K + , Mg 2+ , Ca 2+ and Sr 2+ were linear over a wide dynamic range with regression coefficient better than 0.999. Detection limit of above ions were between 5-30ppb. To prevent the overloading of the cation exchange column, uranium matrix was removed from UO 2 sample by solvent extraction with 30% TBP - TOPO/CCl 4 . Ten sintered UO2 pellets of same lot were analysed and R.S.D. ±10% was obtained. These methods were validated by analysis of ILCE standards of UO 2 . (author)

Optimization of dilute acid hydrolysis of Enteromorpha

Science.gov (United States)

Feng, Dawei; Liu, Haiyan; Li, Fuchao; Jiang, Peng; Qin, Song

2011-11-01

Acid hydrolysis is a simple and direct way to hydrolyze polysaccharides in biomass into fermentable sugars. To produce fermentable sugars effectively and economically for fuel ethanol, we have investigated the hydrolysis of Enteromorpha using acids that are typically used to hydrolyze biomass: H2SO4, HCl, H3PO4 and C4H4O4 (maleic acid). 5%(w/w) Enteromorpha biomass was treated for different times (30, 60, and 90 min) and with different acid concentrations (0.6, 1.0, 1.4, 1.8, and 2.2%, w/w) at 121°C. H2SO4 was the most effective acid in this experiment. We then analyzed the hydrolysis process in H2SO4 in detail using high performance liquid chromatography. At a sulfuric acid concentration of 1.8% and treatment time of 60 min, the yield of ethanol fermentable sugars (glucose and xylose) was high, (230.5 mg/g dry biomass, comprising 175.2 mg/g glucose and 55.3 mg/g xylose), with 48.6% of total reducing sugars being ethanol fermentable. Therefore, Enteromorpha could be a good candidate for production of fuel ethanol. In future work, the effects of temperature and biomass concentration on hydrolysis, and also the fermentation of the hydrolysates to ethanol fuel should be focused on.

Study on preparation method of Zanthoxylum bungeanum seeds kernel oil with zero trans-fatty acids.

Science.gov (United States)

Liu, Tong; Yao, Shi-Yong; Yin, Zhong-Yi; Zheng, Xu-Xu; Shen, Yu

2016-04-01

The seed of Zanthoxylum bungeanum (Z. bungeanum) is a by-product of pepper production and rich in unsaturated fatty acid, cellulose, and protein. The seed oil obtained from traditional producing process by squeezing or extracting would be bad quality and could not be used as edible oil. In this paper, a new preparation method of Z. bungeanum seed kernel oil (ZSKO) was developed by comparing the advantages and disadvantages of alkali saponification-cold squeezing, alkali saponification-solvent extraction, and alkali saponification-supercritical fluid extraction with carbon dioxide (SFE-CO2). The results showed that the alkali saponification-cold squeezing could be the optimal preparation method of ZSKO, which contained the following steps: Z. bungeanum seed was pretreated by alkali saponification under the conditions of adding 10 %NaOH (w/w), solution temperature was 80 °C, and saponification reaction time was 45 min, and pretreated seed was separated by filtering, water washing, and overnight drying at 50 °C, then repeated squeezing was taken until no oil generated at 60 °C with 15 % moisture content, and ZSKO was attained finally using centrifuge. The produced ZSKO contained more than 90 % unsaturated fatty acids and no trans-fatty acids and be testified as a good edible oil with low-value level of acid and peroxide. It was demonstrated that the alkali saponification-cold squeezing process could be scaled up and applied to industrialized production of ZSKO.

Structure and electrical resistivity of alkali-alkali and lithium-based liquid binary alloys

International Nuclear Information System (INIS)

Mishra, A.K.; Mukherjee, K.K.

1990-01-01

Harmonic model potential, developed and used for simple metals is applied here to evaluate hardsphere diameters, which ensure minimum interionic pair potential for alkali-alkali (Na-K, Na-Rb, Na-Cs, K-Rb, K-Cs) and lithium-based (Li-Na, Li-Mg, Li-In, Li-Tl) liquid binary alloys as a function of composition for use in the determination of their partial structure factors. These structure factors are then used to calculate electrical resistivities of alloys considered. The computed values of electrical resistivity as a function of composition agree both, in magnitude and gradient reasonably well with experimental values in all cases except in Cs systems, where the disagreement is appreciable. (author)

Mineralization dynamics of metakaolin-based alkali-activated cements

Science.gov (United States)

Gevaudan, Juan Pablo; Campbell, Kate M.; Kane, Tyler; Shoemaker, Richard K.; Srubar, Wil V.

2017-01-01

This paper investigates the early-age dynamics of mineral formation in metakaolin-based alkali-activated cements. The effects of silica availability and alkali content on mineral formation were investigated via X-ray diffraction and solid-state 29Si magic-angle spinning nuclear magnetic resonance spectroscopy at 2, 7, 14, and 28 days. Silica availability was controlled by using either liquid- (immediate) or solid-based (gradual) sodium silicate supplements. Mineral (zeolitic) and amorphous microstructural characteristics were correlated with observed changes in bulk physical properties, namely shrinkage, density, and porosity. Results demonstrate that, while alkali content controls the mineralization in immediately available silica systems, alkali content controls the silica availability in gradually available silica systems. Immediate silica availability generally leads to a more favorable mineral formation as demonstrated by correlated improvements in bulk physical properties.

A Study of ext ration equilibrium in the system:phosphoric acid produced in Aqaba-uranium-0.5 M de pa-0.125M TOPO diluted in kerosene

International Nuclear Information System (INIS)

Al-Matar, K.A.; Rawajfeh, M.K.

1995-01-01

The extraction of uranium from purified wet process Jordanian phosphoric acid by synergistic solvent 0.5 M de pa and 0.125 M TOPO diluted in kerosene has been studied as a function of temperature and electro-motive force. The uranium distribution coefficient was found to be directly proportional to the electro-motive force up to a limiting point. The uranium distribution coefficient was found to decrease with temperature.Distribution coefficients for the Jordanian acid were found to be higher than those for similar acids from elsewhere.An Aqueous to Organic phase ratio (A/O) recommended for use with the Jordanian acid is 2.5. 11 refs., 6 figs., 2 tab.(Author)

Studies on indigenous ion exchange resins: alkali metal ions-hydrogen ion exchange equilibria

International Nuclear Information System (INIS)

Shankar, S.; Kumar, Surender; Venkataramani, B.

2001-01-01

With a view to select a suitable ion exchange resin for the removal of radionuclides (such as cesium, strontium etc.) from low level radioactive effluents, alkali metal ion -H' exchanges on nine indigenous gel- and macroporous-type and nuclear grade resins have been studied at a total ionic strength of 0.1 mol dm .3 (in the case ofCs' -H' exchange it was 0.05 mol dm .3 ). The expected theoretical capacities were not attained by all the resins for the alkali metal ions. The water content (moles/equiv.) of the fully swollen resins for different alkali metal ionic forms do not follow the usual sequence of greater the tendency of the cation to hydrate the higher the water uptake, but a reverse trend. The ion exchange isotherms (plots of equivalent fractions of the ion in resin phase, N M1 to that in solution, N M ) were not satisfactory and sorption of cations, for most of the resins, was possible only when the acidity of the solution was lowered. The variations of the selectivity coefficient, K, with N M show that the resins are highly cross linked and the selectivity sequence: Cs + >K + >Na + >Li + , obtained for all the resins indicate that hydrated ions were involved in the exchange process. However, the increase in the selectivity was not accompanied by the release of water, but unusual uptake of water, during the exchange process. The characteristics of macroporous resins were not significantly different from those of the gel-type resins. The results are discussed in terms of heterogeneity in the polymer net work, improper sulphonation process resulting in the formation of functional groups at inaccessible sites with weak acidic character and the overall lack of control in the preparation of different resins. (author)

Inhibition Effect of Deanol on Mild Steel Corrosion in Dilute ...

African Journals Online (AJOL)

The influence of deanol on the corrosion behaviour of mild steel in dilute sulphuric acid with sodium chloride addition was studied by means of mass-loss, potentiodynamic polarization, electrode potential monitoring, scanning electron microscopy and statistical analysis. Results show that deanol performed excellently with ...

In situ alkali-silica reaction observed by x-ray microscopy

International Nuclear Information System (INIS)

Kurtis, K.E.; Monteiro, P.J.M.; Brown, J.T.; Meyer-Ilse, W.

1997-01-01

In concrete, alkali metal ions and hydroxyl ions contributed by the cement and reactive silicates present in aggregate can participate in a destructive alkali-silica reaction (ASR). This reaction of the alkalis with the silicates produces a gel that tends to imbibe water found in the concrete pores, leading to swelling of the gel and eventual cracking of the affected concrete member. Over 104 cases of alkali-aggregate reaction in dams and spillways have been reported around the world. At present, no method exists to arrest the expansive chemical reaction which generates significant distress in the affected structures. Most existing techniques available for the examination of concrete microstructure, including ASR products, demand that samples be dried and exposed to high pressure during the observation period. These sample preparation requirements present a major disadvantage for the study of alkali-silica reaction. Given the nature of the reaction and the affect of water on its products, it is likely that the removal of water will affect the morphology, creating artifacts in the sample. The purpose of this research is to observe and characterize the alkali-silica reaction, including each of the specific reactions identified previously, in situ without introducing sample artifacts. For observation of unconditioned samples, x-ray microscopy offers an opportunity for such an examination of the alkali-silica reaction. Currently, this investigation is focusing on the effect of calcium ions on the alkali-silica reaction

In situ alkali-silica reaction observed by x-ray microscopy

Energy Technology Data Exchange (ETDEWEB)

Kurtis, K.E.; Monteiro, P.J.M. [Univ. of California, Berkeley, CA (United States); Brown, J.T.; Meyer-Ilse, W. [Ernest Orlando Lawrence Berkeley National Lab., CA (United States)

1997-04-01

In concrete, alkali metal ions and hydroxyl ions contributed by the cement and reactive silicates present in aggregate can participate in a destructive alkali-silica reaction (ASR). This reaction of the alkalis with the silicates produces a gel that tends to imbibe water found in the concrete pores, leading to swelling of the gel and eventual cracking of the affected concrete member. Over 104 cases of alkali-aggregate reaction in dams and spillways have been reported around the world. At present, no method exists to arrest the expansive chemical reaction which generates significant distress in the affected structures. Most existing techniques available for the examination of concrete microstructure, including ASR products, demand that samples be dried and exposed to high pressure during the observation period. These sample preparation requirements present a major disadvantage for the study of alkali-silica reaction. Given the nature of the reaction and the affect of water on its products, it is likely that the removal of water will affect the morphology, creating artifacts in the sample. The purpose of this research is to observe and characterize the alkali-silica reaction, including each of the specific reactions identified previously, in situ without introducing sample artifacts. For observation of unconditioned samples, x-ray microscopy offers an opportunity for such an examination of the alkali-silica reaction. Currently, this investigation is focusing on the effect of calcium ions on the alkali-silica reaction.

Alkali adsorption on Ni(1 1 1) and their coadsorption with CO and O

International Nuclear Information System (INIS)

Politano, A.; Formoso, V.; Chiarello, G.

2008-01-01

The adsorption of alkalis (Na, K) on Ni(1 1 1) and their coadsorption with CO and O were studied by high-resolution electron energy loss spectroscopy. Loss measurements of clean alkali adlayers provided the expected behaviour of the alkali-substrate vibration energy as a function of the alkali coverage. This result was achieved by eliminating any trace of CO contamination from the alkali adlayer. As a matter of fact, a significant softening of the alkali-Ni vibration energy was revealed in the alkali + CO coadsorbed phase. Moreover, alkali coadsorption with oxygen caused a weakening of the O-Ni bond and a strengthening of the alkali-Ni bond

Experimental (FT-IR, FT-Raman, 1H, 13C NMR) and theoretical study of alkali metal 2-aminobenzoates

Science.gov (United States)

Samsonowicz, M.; Świsłocka, R.; Regulska, E.; Lewandowski, W.

2008-09-01

The influence of lithium, sodium, potassium, rubidium and cesium on the electronic system of the 2-aminobenzoic acid was studied by the methods of molecular spectroscopy. The vibrational (FT-IR, FT-Raman) and NMR ( 1H and 13C) spectra for 2-aminobenzoic acid and its alkali metal salts were recorded. The assignment of vibrational spectra was done on the basis of literature data, theoretical calculations and our previous experience. Characteristic shifts of bands and changes in intensities of bands along the metal series were observed. The changes of chemical shifts of protons ( 1H NMR) and carbons ( 13C NMR) in the series of studied alkali metal 2-aminobenzoates were observed too. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G ∗∗ basis set. Geometric aromaticity indices, dipole moments and energies were also calculated. The theoretical wavenumbers and intensities of IR and Raman spectra were obtained. The calculated parameters were compared to experimental characteristic of studied compounds.

Alkali (Li, K and Na) and alkali-earth (Be, Ca and Mg) adatoms on SiC single layer

Science.gov (United States)

Baierle, Rogério J.; Rupp, Caroline J.; Anversa, Jonas

2018-03-01

First-principles calculations within the density functional theory (DFT) have been addressed to study the energetic stability, and electronic properties of alkali and alkali-earth atoms adsorbed on a silicon carbide (SiC) single layer. We observe that all atoms are most stable (higher binding energy) on the top of a Si atom, which moves out of the plane (in the opposite direction to the adsorbed atom). Alkali atoms adsorbed give raise to two spin unpaired electronic levels inside the band gap leading the SiC single layer to exhibit n-type semiconductor properties. For alkaline atoms adsorbed there is a deep occupied spin paired electronic level inside the band gap. These finding suggest that the adsorption of alkaline and alkali-earth atoms on SiC layer is a powerful feature to functionalize two dimensional SiC structures, which can be used to produce new electronic, magnetic and optical devices as well for hydrogen and oxygen evolution reaction (HER and OER, respectively). Furthermore, we observe that the adsorption of H2 is ruled by dispersive forces (van der Waals interactions) while the O2 molecule is strongly adsorbed on the functionalized system.

[Identification and function test of an alkali-tolerant denitrifying bacterium].

Science.gov (United States)

Wang, Ru; Zheng, Ping; Li, Wei; Chen, Hui; Chen, Tingting; Ghulam, Abbas

2013-04-04

We obtained an alkali-tolerant denitrifying bacterium, and determined its denitrifying activity and alkali-tolerance. An alkali-tolerant denitrifying bacterial strain was obtained by isolation and purification. We identified the bacterial strain by morphological observation, physiological test and 16S rRNA analysis. We determined the denitrifying activity and alkali-tolerance by effects of initial nitrate concentration and initial pH on denitrification. An alkali-tolerant denitrifier strain R9 was isolated from the lab-scale high-rate denitrifying reactor, and it was identified as Diaphorobater nitroreducens. The strain R9 grew heterotrophically with methanol as the electron donor and nitrate as the electron acceptor. The nitrate conversion was 93.25% when strain R9 was cultivated for 288 h with initial nitrate concentration 50 mg/L and initial pH 9.0. The denitrification activity could be inhibited at high nitrate concentration with a half inhibition constant of 202.73 mg N/L. Strain R9 showed a good alkali tolerance with the nitrate removal rate at pH 11.0 remained 86% of that at pH 9.0. Strain R9 was identified as Diaphorobater nitroreducens, and it was an alkali-tolerant denitrifying bacterium with optimum pH value of 9.0.

Maternal exposure to alkali, alkali earth, transition and other metals: Concentrations and predictors of exposure

International Nuclear Information System (INIS)

Hinwood, A.L.; Stasinska, A.; Callan, A.C.; Heyworth, J.; Ramalingam, M.; Boyce, M.; McCafferty, P.; Odland, J.Ø.

2015-01-01

Most studies of metals exposure focus on the heavy metals. There are many other metals (the transition, alkali and alkaline earth metals in particular) in common use in electronics, defense industries, emitted via combustion and which are naturally present in the environment, that have received limited attention in terms of human exposure. We analysed samples of whole blood (172), urine (173) and drinking water (172) for antimony, beryllium, bismuth, cesium, gallium, rubidium, silver, strontium, thallium, thorium and vanadium using ICPMS. In general most metals concentrations were low and below the analytical limit of detection with some high concentrations observed. Few factors examined in regression models were shown to influence biological metals concentrations and explained little of the variation. Further study is required to establish the source of metals exposures at the high end of the ranges of concentrations measured and the potential for any adverse health impacts in children. - This study has demonstrated exposure to alkali, alkali earth and transition metals in pregnant women with factors such as breastfeeding, fish oil use and diet affecting exposures

Theoretical evaluation on selective adsorption characteristics of alkali metal-based sorbents for gaseous oxidized mercury.

Science.gov (United States)

Tang, Hongjian; Duan, Yufeng; Zhu, Chun; Cai, Tianyi; Li, Chunfeng; Cai, Liang

2017-10-01

Alkali metal-based sorbents are potential for oxidized mercury (Hg 2+ ) selective adsorption but show hardly effect to elemental mercury (Hg 0 ) in flue gas. Density functional theory (DFT) was employed to investigate the Hg 0 and HgCl 2 adsorption mechanism over alkali metal-based sorbents, including calcium oxide (CaO), magnesium oxide (MgO), potassium chloride (KCl) and sodium chloride (NaCl). Hg 0 was found to weakly interact with CaO (001), MgO (001), KCl (001) and NaCl (001) surfaces while HgCl 2 was effectively adsorbed on top-O and top-Cl sites. Charge transfer and bond population were calculated to discuss the covalency and ionicity of HgCl 2 bonding with the adsorption sites. The partial density of states (PDOS) analysis manifests that HgCl 2 strongly interacts with surface sites through the orbital hybridizations between Hg and top O or Cl. Frontier molecular orbital (FMO) energy and Mulliken electronegativity are introduced as the quantitative criteria to evaluate the reactivity of mercury species and alkali metal-based sorbents. HgCl 2 is identified as a Lewis acid and more reactive than Hg 0 . The Lewis basicity of the four alkali metal-based sorbents is predicted as the increasing order: NaCl < MgO < KCl < CaO, in consistence with the trend of HgCl 2 adsorption energies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mild acid and alkali treated clay minerals enhance bioremediation of polycyclic aromatic hydrocarbons in long-term contaminated soil: A 14C-tracer study.

Science.gov (United States)

Biswas, Bhabananda; Sarkar, Binoy; Rusmin, Ruhaida; Naidu, Ravi

2017-04-01

Bioremediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soils requires a higher microbial viability and an increased PAH bioavailability. The clay/modified clay-modulated bacterial degradation could deliver a more efficient removal of PAHs in soils depending on the bioavailability of the compounds. In this study, we modified clay minerals (smectite and palygorskite) with mild acid (HCl) and alkali (NaOH) treatments (0.5-3 M), which increased the surface area and pore volume of the products, and removed the impurities without collapsing the crystalline structure of clay minerals. In soil incubation studies, supplements with the clay products increased bacterial growth in the order: 0.5 M HCl ≥ unmodified ≥ 0.5 M NaOH ≥ 3 M NaOH ≥ 3 M HCl for smectite, and 0.5 M HCl ≥ 3 M NaOH ≥ 0.5 M NaOH ≥ 3 M HCl ≥ unmodified for palygorskite. A 14 C-tracing study showed that the mild acid/alkali-treated clay products increased the PAH biodegradation (5-8%) in the order of 0.5 M HCl ≥ unmodified > 3 M NaOH ≥ 0.5 M NaOH for smectite, and 0.5 M HCl > 0.5 M NaOH ≥ unmodified ≥ 3 M NaOH for palygorskite. The biodegradation was correlated (r = 0.81) with the bioavailable fraction of PAHs and microbial growth as affected particularly by the 0.5 M HCl and 0.5 M NaOH-treated clay minerals. These results could be pivotal in developing a clay-modulated bioremediation technology for cleaning up PAH-contaminated soils and sediments in the field. Copyright © 2017 Elsevier Ltd. All rights reserved.

Alkali content of fly ash : measuring and testing strategies for compliance.

Science.gov (United States)

2015-04-01

Sodium and potassium are the common alkalis present in fly ash. Excessive amounts of fly ash alkalis can cause efflorescence : problems in concrete products and raise concern about the effectiveness of the fly ash to mitigate alkali-silica reaction (...

Metal-mediated aminocatalysis provides mild conditions: Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions

Directory of Open Access Journals (Sweden)

Matthias Leven

2013-01-01

Full Text Available Four catalysts based on new amides of chiral 1,2-diamines and 2-sulfobenzoic acid have been developed. The alkali-metal salts of these betaine-like amides are able to form imines with enones, which are activated by Lewis acid interaction for nucleophilic attack by 4-hydroxycoumarin. The addition of 4-hydroxycoumarin to enones gives ee’s up to 83% and almost quantitative yields in many cases. This novel type of catalysis provides an effective alternative to conventional primary amino catalysis were strong acid additives are essential components.

Interaction of alkali metal nitrates with calcium carbonate and kyanite

International Nuclear Information System (INIS)

Protsyuk, A.P.; Malakhov, A.I.; Karabanov, V.P.; Lebedeva, L.P.

1978-01-01

Thermographic, thermodynamic and X-ray phase studies have been made into the interaction of alkali metal nitrates with calcium carbonate and kyanite. Examined among other things was the effect of water vapor and carbon dioxide on the interaction between alkali metal nitrates and kyanite. The chemical mechanism of the occurring processes has been established. The interaction with calcium carbonates results in the formation of alkali metal carbonates and calcium oxide with liberation of nitrogen oxide and oxygen. The products of the interaction with kyanite are shown to be identical with the compounds forming when alkali metal carbonates are used

Comparison of aqueous ammonia and dilute acid pretreatment of bamboo fractions: Structure properties and enzymatic hydrolysis.

Science.gov (United States)

Xin, Donglin; Yang, Zhong; Liu, Feng; Xu, Xueru; Zhang, Junhua

2015-01-01

The effect of two pretreatments methods, aqueous ammonia (SAA) and dilute acid (DA), on the chemical compositions, cellulose crystallinity, morphologic change, and enzymatic hydrolysis of bamboo fractions (bamboo yellow, timber, green, and knot) was compared. Bamboo fractions with SAA pretreatment had better hydrolysability than those with DA pretreatment. High crystallinity index resulted in low hydrolysis yield in the conversion of SAA pretreated bamboo fractions, not DA pretreated fractions. The increase of cellulase loading had modestly positive effect in the hydrolysis of both SAA and DA pretreated bamboo fractions, while supplement of xylanase significantly increased the hydrolysis of the pretreated bamboo fractions, especially after SAA pretreatment. The results indicated that SAA pretreatment was more effective than DA pretreatment in conversion of bamboo fractions, and supplementation of xylanase was necessary in effective conversion of the SAA pretreated fractions into fermentable sugars. Copyright © 2014 Elsevier Ltd. All rights reserved.

High-performance ion-exchange chromatography of alkali metals with conductivity detection

International Nuclear Information System (INIS)

Ahmad, M.; Khan, A.R.

1981-01-01

High-performance ion-exchange chromatography of alkali metal and ammonium ions was studied using a conductivity meter as detector. Elution with 0.003 N mitric acid gave excellent resolution. Sensitivity levels, for a 200 micro litre injection, vary from 5 ppm for potassium to 0.1 ppm for lithium. A method to decrease retention times by reducing the exchange capacity of the cation exchange column used by loading it with calciumions, without affecting the resolation, has been described. Application of the method to water, soil and uranium dioxide samples has been demonstrated. (author)

Electronic and atomic structures of liquid tellurium containing alkali elements

International Nuclear Information System (INIS)

Kawakita, Yukinobu; Yao, Makoto; Endo, Hirohisa.

1997-01-01

The measurements of electrical conductivity σ, density, EXAFS and neutron scattering were carried out for liquid K-Te and Rb-Te mixtures. The conductivity σ decreases rapidly with alkali concentration and a metal-semiconductor transition occurs at about 10 at.% alkali. It is found that the compositional variation of σ is nearly independent of the alkali species. The Te-Te bond length deduced from EXAFS and neutron scattering measurements is 2.8 A and changes little with alkali concentrations. The average distances from K and Rb atom to Te atoms are 3.6 A and 3.8 A, respectively. Two kinds of relaxation processes are observed in quasielastic neutron scattering for K 20 Te 80 . Upon the addition of alkali the interaction between the neighbouring Te chains, which is responsible for the metallic conduction, weaken considerably. (author)

Study of isobutyric acid reactivity by electron spin resonance and infrared spectroscopy of the sodium salt and of 1-vanado-11-molybdophosphoric acid; Etude de la reactivite de l`acide isobutyrique par spectroscopie infrarouge et resonance paramagnetique electronique du sel de sodium et de l`acide de l`ion 1-vanado-11-molybdophosphorique

Energy Technology Data Exchange (ETDEWEB)

Rabia, C.; Bettahar, M.M. [Universite des sciences et de technologies, Houari-Boumediene, Algiers (Algeria); Fournier, M. [Universite des Sciences et technologies de Lille, 59 - Villeneuve d`Ascq (France)

1997-11-01

The alkaline salt 1-vanado-11-molybdo-phosphore acid as been investigated in isobutyric absorption-desorption-re-oxidation cycles by IR and ESR spectroscopies in comparison to the bulk acid compound. The stability of the active phase in catalysis seems to be related to the formation of a cubic phase depending strongly on the presence of water vapor in the gas stream. This phase can be generated from an alkali precursor subject to a moderate thermal treatment leading to a dispersion of di-oxovanadium cation into the alkali-12-molybdophosphate lattice. (authors) 14 refs.

Survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces

International Nuclear Information System (INIS)

Neskovic, N.; Ciric, D.; Perovic, B.

1982-01-01

The survival probability in small angle scattering of low energy alkali ions from alkali covered metal surfaces is considered. The model is based on the momentum approximation. The projectiles are K + ions and the target is the (001)Ni+K surface. The incident energy is 100 eV and the incident angle 5 0 . The interaction potential of the projectile and the target consists of the Born-Mayer, the dipole and the image charge potentials. The transition probability function corresponds to the resonant electron transition to the 4s projectile energy level. (orig.)

Transcriptome alteration in a rice introgression line with enhanced alkali tolerance.

Science.gov (United States)

Zhang, Yunhong; Lin, Xiuyun; Ou, Xiufang; Hu, Lanjuan; Wang, Jinming; Yang, Chunwu; Wang, Shucai; Liu, Bao

2013-07-01

Alkali stress inhibits plant growth and development and thus limits crop productivity. To investigate the possible genetic basis of alkali tolerance in rice, we generated an introgressed rice line (K83) with significantly enhanced tolerance to alkali stress compared to its recipient parental cultivar (Jijing88). By using microarray analysis, we examined the global gene expression profiles of K83 and Jijing88, and found that more than 1200 genes were constitutively and differentially expressed in K83 in comparison to Jijing88 with 572 genes up- and 654 down-regulated. Upon alkali treatment, a total of 347 genes were found up- and 156 down-regulated in K83 compared to 591 and 187, respectively, in Jijing88. Among the up-regulated genes in both K83 and Jijing88, only 34 were constitutively up-regulated in K83, suggesting that both the constitutive differentially expressed genes in K83 and those induced by alkali treatment are most likely responsible for enhanced alkali tolerance. A gene ontology analysis based on all annotated, differentially expressed genes revealed that genes with expression alterations were enriched in pathways involved in metabolic processes, catalytic activity, and transport and transcription factor activities, suggesting that these pathways are associated with alkali stress tolerance in rice. Our results illuminated the novel genetic aspects of alkali tolerance in rice and established a repertory of potential target genes for biotechnological manipulations that can be used to generate alkali-tolerant rice cultivars. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

The alkali-aggregate reaction - concrete microstructure evolution

International Nuclear Information System (INIS)

Regourd, M.; Hornain, H.; Poitevin, P.

1981-01-01

The alkali-aggregate reaction has been studied by scanning electron microscopy and energy dispersive X-ray analysis, electron probe microanalysis, and X-ray diffraction in concretes containing glass aggregates or hornfels and greywacke aggregates. The surface reaction of the natural aggregates in alkaline solutions has been analysed by X-ray photo-electron spectrometry. The study of concretes with glass aggregates stored at 20 degrees Celcius and 100 percent relative humidity has revealed, irrespective of alkali content and type of cement, the formation of a gel containing SiO 2 , Na 2 O, CaO, MgO and Al 2 O 3 . Under heat and pressure (210 degrees Celcius at MPa for 48 hours), the gel crystallizes and yields silicates not very different from tobermorite found in autoclaved normal concretes but cotaining Na and K in solid solutions. The alkali reaction in two natural aggregate concretes, is also shown by the formation of gels and silicate crystals. The progressive structuring of the gels in silicate crystals is promoted by an increase in temperature. Ettringite and Ca(OH) 2 reinforce the alkali-aggregate reaction which may be looked upon as a hydration reaction, partially of the pozzolanic type

Intermetallic Competition in the Fragmentation of Trimetallic Au-Zn-Alkali Complexes.

Science.gov (United States)

Lang, Johannes; Cayir, Merve; Walg, Simon P; Di Martino-Fumo, Patrick; Thiel, Werner R; Niedner-Schatteburg, Gereon

2016-02-12

Cationization is a valuable tool to enable mass spectrometric studies on neutral transition-metal complexes (e.g., homogenous catalysts). However, knowledge of potential impacts on the molecular structure and catalytic reactivity induced by the cationization is indispensable to extract information about the neutral complex. In this study, we cationize a bimetallic complex [AuZnCl3 ] with alkali metal ions (M(+) ) and investigate the charged adducts [AuZnCl3 M](+) by electrospray ionization mass spectrometry (ESI-MS). Infrared multiple photon dissociation (IR-MPD) in combination with density functional theory (DFT) calculations reveal a μ(3) binding motif of all alkali ions to the three chlorido ligands. The cationization induces a reorientation of the organic backbone. Collision-induced dissociation (CID) studies reveal switches of fragmentation channels by the alkali ion and by the CID amplitude. The Li(+) and Na(+) adducts prefer the sole loss of ZnCl2 , whereas the K(+) , Rb(+) , and Cs(+) adducts preferably split off MCl2 ZnCl. Calculated energetics along the fragmentation coordinate profiles allow us to interpret the experimental findings to a level of subtle details. The Zn(2+) cation wins the competition for the nitrogen coordination sites against K(+) , Rb(+) , and Cs(+) , but it loses against Li(+) and Na(+) in a remarkable deviation from a naive hard and soft acids and bases (HSAB) concept. The computations indicate expulsion of MCl2 ZnCl rather than of MCl and ZnCl2 . © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Uracil in formic acid hydrolysates of deoxyribonucleic acid

Science.gov (United States)

Schein, Arnold H.

1966-01-01

1. When DNA is hydrolysed with formic acid for 30min. at 175° and the hydrolysate is chromatographed on paper with propan-2-ol–2n-hydrochloric acid, in addition to expected ultraviolet-absorbing spots corresponding to guanine, adenine, cytosine and thymine, an ultraviolet-absorbing region with RF similar to that of uracil can be detected. Uracil was separated from this region and identified by its spectra in acid and alkali, and by its RF in several solvent systems. 2. Cytosine, deoxyribocytidine and deoxyribocytidylic acid similarly treated with formic acid all yielded uracil, as did a mixture of deoxyribonucleotides. 3. Approx. 4% of deoxyribonucleotide cytosine was converted into uracil by the formic acid treatment. ImagesFig. 1. PMID:5949371

Equilibrium electrode U(4)-U and redox U(4)-U(3) potentials in molten alkali metal chlorides medium

Energy Technology Data Exchange (ETDEWEB)

Smirnov, M V; Kudyakov, V Ya; Komarov, V E; Salyulev, A B [AN SSSR, Sverdlovsk. Inst. Ehlektrokhimii

1979-02-01

Conditional standard electrode potentials of uranium are determined for diluted solutions of its tetrachloride in alkali metal chloride melts (LiCl, NaCl, NaCl-KCl, KCl, RbCl and CsCl) when using U(4) ion activity coefficient values experimentally found by the tensimetric method. These potentials shift to the electronegative side at the temperature decrease and alkali cation radius increase rsub(Msup(+)) according to the empiric ratio E*U(4)-U= -3.06+6.87x10/sup -4/ T-(1.67-10/sup -4/T-0.44) 1/rsub(Msup(+)) +-0.01. The temperature dependences of formal conditional redox potentials of the U(4)-U(3) system for above melted chlorides are estimated. The E*U(4)-U(3) value also becomes more electronegative in the series LiCl, NaCl, NaCl-KCl, KCl, RbCl and CsCl. This alternation is satisfactorily described by the empiric expression E*U(4)-U(3)= -1.74+1.74x10/sup -4/T-(0.71x10/sup -4/T-0.20) 1rsub(Msup(+)) +-0.05. The calculated values Eu*(4)-U(3) are compared with those directly measured for the NaCl-KCl equimolar mixture and 3LiCl-2KCl eutectic mixture. A satisfactory confirmity has been observed.

Equilibrium electrode U(4)-U and redox U(4)-U(3) potentials in molten alkali metal chlorides medium

International Nuclear Information System (INIS)

Smirnov, M.V.; Kudyakov, V.Ya.; Komarov, V.E.; Salyulev, A.B.

1979-01-01

Conditional standard electrode potentials of uranium are determined for diluted solutions of its tetrachloride in alkali metal chloride melts (LiCl, NaCl, NaCl-KCl, KCl, RbCl and CsCl) when using U(4) ion activity coefficient values experimentally found by the tensimetric method. These potentials shift to the electronegative side at the temperature decrease and alkali cation radius increase rsub(Msup(+)) according to the empiric ratio E*U(4)-U= -3.06+6.87x10 -4 T-(1.67-10 -4 T-0.44) 1/rsub(Msup(+)) +-0.01. The temperature dependences of formal conditional redox potentials of the U(4)-U(3) system for above melted chlorides are estimated. The E*U(4)-U(3) value also becomes more electronegative in the series LiCl, NaCl, NaCl-KCl, KCl, RbCl and CsCl. This alternation is satisfactorily described by the empiric expression E*U(4)-U(3)= -1.74+1.74x10 -4 T-(0.71x10 -4 T-0.20) 1rsub(Msup(+)) +-0.05. The calculated values Eu*(4)-U(3) are compared with those directly measured for the NaCl-KCl equimolar mixture and 3LiCl-2KCl eutectic mixture. A satisfactory confirmity has been observed

Brewing Bokashi: Strengthening Student Skills in Dilution Theory through Fermentation Analysis

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Robert E. Zdor

2016-05-01

Full Text Available One of the basic microbiological techniques that students should master is that of using dilution theory to calculate the levels of bacteria in a fluid. This tip reports on using a rice water-milk fermentation mixture termed Bokashi as an easily implemented exercise in the basic microbiological lab to give students multiple opportunities to use dilution theory. Due to the shifts in bacterial community composition over time, a variety of microbes can be cultured using selective and nonselective media. Microscopic observation and the use of GEN III microplates to determine the collective phenotypic pattern of the mixture both give additional opportunities for students to hone their skills in bacterial analysis. Due to the decrease in the pH of the mixture over time, the notion of acid tolerance in bacteria can be explored and assessed using the microplate. By performing multiple rounds of serial dilutions and spread plating, students can practice their skill at using dilution theory several times over the course of the exercise.

Alkali control of high-grade metamorphism and granitization

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Oleg G. Safonov

2014-09-01

Full Text Available We review petrologic observations of reaction textures from high-grade rocks that suggest the passage of fluids with variable alkali activities. Development of these reaction textures is accompanied by regular compositional variations in plagioclase, pyroxenes, biotite, amphibole and garnet. The textures are interpreted in terms of exchange and net-transfer reactions controlled by the K and Na activities in the fluids. On the regional scale, these reactions operate in granitized, charnockitized, syenitized etc. shear zones within high-grade complexes. Thermodynamic calculations in simple chemical systems show that changes in mineral assemblages, including the transition from the hydrous to the anhydrous ones, may occur at constant pressure and temperature due only to variations in the H2O and the alkali activities. A simple procedure for estimating the activity of the two major alkali oxides, K2O and Na2O, is implemented in the TWQ software. Examples of calculations are presented for well-documented dehydration zones from South Africa, southern India, and Sri Lanka. The calculations have revealed two end-member regimes of alkalis during specific metamorphic processes: rock buffered, which is characteristic for the precursor rocks containing two feldspars, and fluid-buffered for the precursor rocks without K-feldspar. The observed reaction textures and the results of thermodynamic modeling are compared with the results of available experimental studies on the interaction of the alkali chloride and carbonate-bearing fluids with metamorphic rocks at mid-crustal conditions. The experiments show the complex effect of alkali activities in the fluid phase on the mineral assemblages. Both thermodynamic calculations and experiments closely reproduce paragenetic relations theoretically predicted by D.S. Korzhinskii in the 1940s.

Comparative study of diode-pumped alkali vapor laser and exciplex-pumped alkali laser systems and selection principal of parameters

Science.gov (United States)

Huang, Wei; Tan, Rongqing; Li, Zhiyong; Han, Gaoce; Li, Hui

2017-03-01

A theoretical model based on common pump structure is proposed to analyze the output characteristics of a diode-pumped alkali vapor laser (DPAL) and XPAL (exciplex-pumped alkali laser). Cs-DPAL and Cs-Ar XPAL systems are used as examples. The model predicts that an optical-to-optical efficiency approaching 80% can be achieved for continuous-wave four- and five-level XPAL systems with broadband pumping, which is several times the pumped linewidth for DPAL. Operation parameters including pumped intensity, temperature, cell's length, mixed gas concentration, pumped linewidth, and output coupler are analyzed for DPAL and XPAL systems based on the kinetic model. In addition, the predictions of selection principal of temperature and cell's length are also presented. The concept of the equivalent "alkali areal density" is proposed. The result shows that the output characteristics with the same alkali areal density but different temperatures turn out to be equal for either the DPAL or the XPAL system. It is the areal density that reflects the potential of DPAL or XPAL systems directly. A more detailed analysis of similar influences of cavity parameters with the same areal density is also presented.

Alkali solution extraction of rice residue protein isolates: Influence of alkali concentration on protein functional, structural properties and lysinoalanine formation.

Science.gov (United States)

Hou, Furong; Ding, Wenhui; Qu, Wenjuan; Oladejo, Ayobami Olayemi; Xiong, Feng; Zhang, Weiwei; He, Ronghai; Ma, Haile

2017-03-01

This study evaluated the nutrient property and safety of the rice residue protein isolates (RRPI) product (extracted by different alkali concentrations) by exploring the protein functional, structural properties and lysinoalanine (LAL) formation. The results showed that with the rising of alkali concentration from 0.03M to 0.15M, the solubility, emulsifying and foaming properties of RRPI increased at first and then descended. When the alkali concentration was greater than 0.03M, the RRPI surface hydrophobicity decreased and the content of thiol and disulfide bond, Lys and Cys significantly reduced. By the analysis of HPLC, the content of LAL rose up from 276.08 to 15,198.07mg/kg and decreased to 1340.98mg/kg crude protein when the alkali concentration increased from 0.03 to 0.09M and until to 0.15M. These results indicated that RRPI alkaline extraction concentration above 0.03M may cause severe nutrient or safety problems of protein. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acid Balance, Dietary Acid Load, and Bone Effects—A Controversial Subject

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Lynda Frassetto

2018-04-01

Full Text Available Modern Western diets, with higher contents of animal compared to fruits and vegetable products, have a greater content of acid precursors vs. base precursors, which results in a net acid load to the body. To prevent inexorable accumulation of acid in the body and progressively increasing degrees of metabolic acidosis, the body has multiple systems to buffer and titrate acid, including bone which contains large quantities of alkaline salts of calcium. Both in vitro and in vivo studies in animals and humans suggest that bone base helps neutralize part of the dietary net acid load. This raises the question of whether decades of eating a high acid diet might contribute to the loss of bone mass in osteoporosis. If this idea is true, then additional alkali ingestion in the form of net base-producing foods or alkalinizing salts could potentially prevent this acid-related loss of bone. Presently, data exists that support both the proponents as well as the opponents of this hypothesis. Recent literature reviews have tended to support either one side or the other. Assuming that the data cited by both sides is correct, we suggest a way to reconcile the discordant findings. This overview will first discuss dietary acids and bases and the idea of changes in acid balance with increasing age, then review the evidence for and against the usefulness of alkali therapy as a treatment for osteoporosis, and finally suggest a way of reconciling these two opposing points of view.

Multistage dilute acid leaching of a medium grade iron ore to super-concentrate

Directory of Open Access Journals (Sweden)

Adeleke A.A.

2014-01-01

Full Text Available The phosphorous laden Koton Karfe iron ore is a medium grade iron ore deposit in Nigeria that can be upgraded as a super-concentrate for use at the Aladja Steel Midrex plant. The 75 μm size sample fraction of the ore was preconcentrated with shaking table and leached in the oven at atmospheric pressure with dilute hydrochloric acid in single and multistage leaching sequences of H2O-HCl-H2O and HCl-H2O-H2O. The as-received, as-tabled and asleached samples were then subjected to X-ray fluorescence and microscopic analyses. The results obtained showed that the H2O-HCl-H2O route produced a higher grade concentrate that assayed 68.54% Fe indicating about 58% upgrade in iron content; while the phosphorus and sulphur contents were reduced by about 77 and 99.6% respectively. In addition, the silicon, manganese, and titanium contents were drastically reduced, while potassium was completely eliminated. The upgrade of iron content in the ore to 68.54% and the drastic reduction in phosphorous and sulphur contents has thus rendered the Koton Karfe iron ore suitable for use as a super concentrate for the Aladja steel plant direct reduction iron making process.

Alkaline Fe(III) reduction by a novel alkali-tolerant Serratia sp. isolated from surface sediments close to Sellafield nuclear facility, UK.

Science.gov (United States)

Thorpe, Clare L; Morris, Katherine; Boothman, Christopher; Lloyd, Jonathan R

2012-02-01

Extensive denitrification resulted in a dramatic increase in pH (from 6.8 to 9.5) in nitrate-impacted, acetate-amended sediment microcosms containing sediment representative of the Sellafield nuclear facility, UK. Denitrification was followed by Fe(III) reduction, indicating the presence of alkali-tolerant, metal-reducing bacteria. A close relative (99% 16S rRNA gene sequence homology) to Serratia liquefaciens dominated progressive enrichment cultures containing Fe(III)-citrate as the sole electron acceptor at pH 9 and was isolated aerobically using solid media. The optimum growth conditions for this facultatively anaerobic Serratia species were investigated, and it was capable of metabolizing a wide range of electron acceptors including oxygen, nitrate, FeGel, Fe-NTA and Fe-citrate and electron donors including acetate, lactate, formate, ethanol, glucose, glycerol and yeast extract at an optimum pH of c. 6.5 at 20 °C. The alkali tolerance of this strain extends the pH range of highly adaptable Fe(III)-reducing Serratia species from mildly acidic pH values associated with acid mine drainage conditions to alkali conditions representative of subsurface sediments stimulated for extensive denitrification and metal reduction. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

40 CFR 721.5452 - Alkali metal salt of halogenated organoborate (generic).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkali metal salt of halogenated... Specific Chemical Substances § 721.5452 Alkali metal salt of halogenated organoborate (generic). (a... generically as alkali metal salt of halogenated organoborate (PMN P-00-0638) is subject to reporting under...

Physiological Evaluation of Alkali-Salt Tolerance of Thirty Switchgrass (Panicum virgatum Lines.

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Guofu Hu

Full Text Available Soil salt-alkalization is a major limiting factor for crop production in many regions. Switchgrass (Panicum virgatum L. is a warm-season C4 perennial rhizomatous bunchgrass and a target lignocellulosic biofuel species. The objective of this study was to evaluate relative alkali-salt tolerance among 30 switchgrass lines. Tillers of each switchgrass line were transplanted into pots filled with fine sand. Two months after transplanting, plants at E5 developmental stage were grown in either half strength Hoagland's nutrient solution with 0 mM Na+ (control or half strength Hoagland's nutrient solution with 150 mM Na+ and pH of 9.5 (alkali-salt stress treatment for 20 d. Alkali-salt stress damaged cell membranes [higher electrolyte leakage (EL], reduced leaf relative water content (RWC, net photosynthetic rate (Pn, stomatal conductance (gs, and transpiration rate (Tr. An alkali-salt stress tolerance trait index (ASTTI for each parameter was calculated based on the ratio of the value under alkali-salt stress and the value under non-stress conditions for each parameter of each line. Relative alkali-salt tolerance was determined based on principal components analysis and cluster analysis of the physiological parameters and their ASTTI values. Significant differences in alkali-salt stress tolerance were found among the 30 lines. Lowland lines TEM-SEC, Alamo, TEM-SLC and Kanlow were classified as alkali-salt tolerant. In contrast, three lowland lines (AM-314/MS-155, BN-13645-64 and two upland lines (Caddo and Blackwell-1 were classified as alkali-salt sensitive. The results suggest wide variations exist in alkali-salt stress tolerance among the 30 switchgrass lines. The approach of using a combination of principal components and cluster analysis of the physiological parameters and related ASTTI is feasible for evaluating alkali-salt tolerance in switchgrass.

Physiological Evaluation of Alkali-Salt Tolerance of Thirty Switchgrass (Panicum virgatum) Lines.

Science.gov (United States)

Hu, Guofu; Liu, Yiming; Zhang, Xunzhong; Yao, Fengjiao; Huang, Yan; Ervin, Erik H; Zhao, Bingyu

2015-01-01

Soil salt-alkalization is a major limiting factor for crop production in many regions. Switchgrass (Panicum virgatum L.) is a warm-season C4 perennial rhizomatous bunchgrass and a target lignocellulosic biofuel species. The objective of this study was to evaluate relative alkali-salt tolerance among 30 switchgrass lines. Tillers of each switchgrass line were transplanted into pots filled with fine sand. Two months after transplanting, plants at E5 developmental stage were grown in either half strength Hoagland's nutrient solution with 0 mM Na+ (control) or half strength Hoagland's nutrient solution with 150 mM Na+ and pH of 9.5 (alkali-salt stress treatment) for 20 d. Alkali-salt stress damaged cell membranes [higher electrolyte leakage (EL)], reduced leaf relative water content (RWC), net photosynthetic rate (Pn), stomatal conductance (gs), and transpiration rate (Tr). An alkali-salt stress tolerance trait index (ASTTI) for each parameter was calculated based on the ratio of the value under alkali-salt stress and the value under non-stress conditions for each parameter of each line. Relative alkali-salt tolerance was determined based on principal components analysis and cluster analysis of the physiological parameters and their ASTTI values. Significant differences in alkali-salt stress tolerance were found among the 30 lines. Lowland lines TEM-SEC, Alamo, TEM-SLC and Kanlow were classified as alkali-salt tolerant. In contrast, three lowland lines (AM-314/MS-155, BN-13645-64) and two upland lines (Caddo and Blackwell-1) were classified as alkali-salt sensitive. The results suggest wide variations exist in alkali-salt stress tolerance among the 30 switchgrass lines. The approach of using a combination of principal components and cluster analysis of the physiological parameters and related ASTTI is feasible for evaluating alkali-salt tolerance in switchgrass.

Molecular analysis of two mouse dilute locus deletion mutations: Spontaneous dilute lethal20J and radiation-induced dilute prenatal lethal Aa2 alleles

International Nuclear Information System (INIS)

Strobel, M.C.; Seperack, P.K.; Copeland, N.G.; Jenkins, N.A.

1990-01-01

The dilute (d) coat color locus of mouse chromosome 9 has been identified by more than 200 spontaneous and mutagen-induced recessive mutations. With the advent of molecular probes for this locus, the molecular lesion associated with different dilute alleles can be recognized and precisely defined. In this study, two dilute mutations, dilute-lethal20J (dl20J) and dilute prenatal lethal Aa2, have been examined. Using a dilute locus genomic probe in Southern blot analysis, we detected unique restriction fragments in dl20J and Aa2 DNA. Subsequent analysis of these fragments showed that they represented deletion breakpoint fusion fragments. DNA sequence analysis of each mutation-associated deletion breakpoint fusion fragment suggests that both genomic deletions were generated by nonhomologous recombination events. The spontaneous dl20J mutation is caused by an interstitial deletion that removes a single coding exon of the dilute gene. The correlation between this discrete deletion and the expression of all dilute-associated phenotypes in dl20J homozygotes defines the dl20J mutation as a functional null allele of the dilute gene. The radiation-induced Aa2 allele is a multilocus deletion that, by complementation analysis, affects both the dilute locus and the proximal prenatal lethal-3 (pl-3) functional unit. Molecular analysis of the Aa2 deletion breakpoint fusion fragment has provided access to a previously undefined gene proximal to d. Initial characterization of this new gene suggests that it may represent the genetically defined pl-3 functional unit

What infusion flow should be used for mid-dilution hemodiafiltration?

Science.gov (United States)

Maduell, Francisco; Arias, Marta; Fontseré, Néstor; Vera, Manel; Masso, Elisabeth; Garro, Julia; Barros, Xoana; Martina, Maria N; Elena, Montserrat; Bergadá, Eduardo; Cases, Aleix; Bedini, Jose Luis; Campistol, Josep M

2010-01-01

There is still no consensus on the optimal infusion flow (Qi) in mid-dilution hemodiafiltration. The aim of this study was to compare mid-dilution with varying Qi. Prospective study in 25 patients who underwent seven hemodialysis sessions with a Qi of 0, 50, 100, 150, 200, 250 and 300 ml/min. All sessions were well tolerated except Qi 300 ml/min. No significant differences in urea, creatinine, alpha(1)-microglobulin or alpha(1)-acid glycoprotein reduction ratios were observed. beta(2)-Microglobulin, myoglobin and prolactin reduction ratios were higher with Qi 150, 200, 250 and 300 ml/min in comparison with Qi of 0, 50 and 100 ml/min. There were no differences in the removal of small or larger molecules when Qi was 150 ml/min or higher. Optimal Qi in mid-dilution appears to be in the range of 150-250 ml/min since good clinical outcomes, similar efficiency and no technical complications up to a Qi of 250 ml/min were observed.

Alkali resistant Fe-zeolite catalysts for SCR of NO with NH3 in flue gases

DEFF Research Database (Denmark)

Putluru, Siva Sankar Reddy; Jensen, Anker Degn; Riisager, Anders

2011-01-01

. The effect of potassium doping on the acidic and redox properties of the Fe-zeolite catalysts were studied. The prepared catalysts showed high surface area and surface acidity. This is essential for increased alkali resistivity in comparison with conventional metal oxide supports like, e.g. TiO2 and ZrO2......, towards e.g. potassium salts in flue gases from biomass fired power plants. These properties allowed both undoped and potassium doped Fe-zeolite catalysts to posses high activity during the selective catalytic reduction (SCR) of NO with NH3. The extent of deactivation of the Fe-zeolite catalysts...

40 CFR 721.5985 - Fatty alkyl phosphate, alkali metal salt (generic).

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty alkyl phosphate, alkali metal... Specific Chemical Substances § 721.5985 Fatty alkyl phosphate, alkali metal salt (generic). (a) Chemical... as a fatty alkyl phosphate, alkali metal salt (PMN P-99-0385) is subject to reporting under this...

40 CFR 721.4660 - Alcohol, alkali metal salt.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alcohol, alkali metal salt. 721.4660 Section 721.4660 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.4660 Alcohol, alkali metal sal...

Utilization of Mineral Wools as Alkali-Activated Material Precursor

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Juho Yliniemi

2016-04-01

Full Text Available Mineral wools are the most common insulation materials in buildings worldwide. However, mineral wool waste is often considered unrecyclable because of its fibrous nature and low density. In this paper, rock wool (RW and glass wool (GW were studied as alkali-activated material precursors without any additional co-binders. Both mineral wools were pulverized by a vibratory disc mill in order to remove the fibrous nature of the material. The pulverized mineral wools were then alkali-activated with a sodium aluminate solution. Compressive strengths of up to 30.0 MPa and 48.7 MPa were measured for RW and GW, respectively, with high flexural strengths measured for both (20.1 MPa for RW and 13.2 MPa for GW. The resulting alkali-activated matrix was a composite-type in which partly-dissolved fibers were dispersed. In addition to the amorphous material, sodium aluminate silicate hydroxide hydrate and magnesium aluminum hydroxide carbonate phases were identified in the alkali-activated RW samples. The only crystalline phase in the GW samples was sodium aluminum silicate. The results of this study show that mineral wool is a very promising raw material for alkali activation.

Heteropoly acid promoted catalyst for SCR of NOx with ammonia

DEFF Research Database (Denmark)

2012-01-01

The present invention concerns the selective removal of nitrogen oxides (NOx) from gases. In particular, the invention concerns a process, a highly alkali metal resistant heteropoly acid promoted catalyst and the use of said catalyst for removal of NOx from exhaust or flue gases, said gases...... comprising alkali or earth alkali metals. Such gases comprise for example flue gases arising from the burning of biomass, combined biomass and fossil fuel, and from waste incineration units. The process comprises the selective catalytic reduction (SCR) of NOx, such as nitrogen dioxide (NO2) and nitrogen...

Thorium valency in molten alkali halides in equilibrium with metallic thorium

International Nuclear Information System (INIS)

Smirnov, M.V.; Kudyakov, V.Ya.

1983-01-01

Metallic thorium is shown to corrode in molten alkali halides even in the absence of external oxidizing agents, alkali cations acting as oxidizing agents. Its corrosion rate grows in the series of alkali chlorides from LiCl to CsCl at constant temperature. Substituting halide anions for one another exerts a smaller influence, the rate rising slightly in going from chlorides to bromides and iodides, having the same alkali cations. Thorium valency is determined coulometrically, the metal being dissolved anodically in molten alkali halides and their mixtures. In fluoride melts it is equal to 4 but in chloride, bromide and iodide ones, as a rule, it has non-integral values between 4 and 2 which diminish as the temperature is raised, as the thorium concentration is lowered, as the radii of alkali cations decrease and those of halide anions increase. The emf of cells Th/N ThHlsub(n) + (1-N) MHl/MHl/C, Hlsub(2(g)) where Hl is Cl, Br or I, M is Li, Na, K, Cs or Na + K, and N < 0.05, is measured as a function of concentration at several temperatures. Expressions are obtained for its concentration dependence. The emf grows in the series of alkali chlorides from LiCl to CsCl, other conditions being equal. (author)

Long term effect of alkali types on waste activated sludge hydrolytic acidification and microbial community at low temperature.

Science.gov (United States)

Jin, Baodan; Wang, Shuying; Xing, Liqun; Li, Baikun; Peng, Yongzhen

2016-01-01

The effect of four alkali reagents (NaOH, KOH, Ca(OH)2, mixed alkali) on waste activated sludge (WAS) hydrolytic acidification and microbial community was studied in semi-continuous fermentation systems at low temperature (15°C) over long term operational time (65day). The results showed that protein and polysaccharide of NaOH (124.26, 11.92) was similar to that of KOH (109.53, 11.30), both were higher than Ca(OH)2 (70.66, 3.74) and mixed alkali (90.66, 8.71). The short chain fatty acids (SCFAs) of NaOH (231.62) was higher than KOH (220.62mg chemical oxygen demand (COD)/g VSS). Although Ca(OH)2 system had strong acidification capacity, the shortage of SCFAs occurred due to the low activity of hydrolase. Illumina MiSeq sequencing revealed that Tissierella and Erysipelothrix were enriched in the NaOH and Ca(OH)2 systems, where Peptostreptococcaceae incertae_sedis was enriched in the NaOH and KOH systems, less Anaerolinea was involved in Ca(OH)2 condition. Copyright © 2015. Published by Elsevier Ltd.

Alkali resistant Ni-loaded yolk-shell catalysts for direct internal reforming in molten carbonate fuel cells

Science.gov (United States)

Jang, Won-Jun; Hong, Young Jun; Kim, Hak-Min; Shim, Jae-Oh; Roh, Hyun-Seog; Kang, Yun Chan

2017-06-01

A facile and scalable spray pyrolysis process is applied to synthesize multi-shelled Ni-loaded yolk-shell catalysts on various supports (Al2O3, CeO2, ZrO2, and La(OH)3). The prepared catalysts are applied to direct internal reforming (DIR) in a molten carbonate fuel cell (MCFC). Even on exposure to alkali hydroxide vapors, the Ni-loaded yolk-shell catalysts remain highly active for DIR-MCFCs. The Ni@Al2O3 microspheres show the highest conversion (92%) of CH4 and the best stability among the prepared Ni-loaded yolk-shell catalysts. Although the initial CH4 conversion of the Ni@ZrO2 microspheres is higher than that of the Ni@CeO2 microspheres, the Ni@CeO2 microspheres are more stable. The catalytic performance is strongly dependent on the surface area and acidity and also partly dependent on the reducibility. The acidic nature of Al2O3 combined with its high surface area and yolk-shell structure enhances the adsorption of CH4 and resistance against alkali poisoning, resulting in efficient DIR-MCFC reactions.

ALKALI-ACTIVATION KINETICS OF PHOSPHORUS SLAG CEMENT USING COMPRESSIVE STRENGTH DATA

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Hojjatollah Maghsoodloorad

2015-09-01

Full Text Available In this research, through compressive strength data, the order and kinetics of alkali-activation of phosphorus slag activated with two compound activators of NaOH + Na2CO3 and Na2CO3 + Ca(OH2, has been evaluated. The kinetics and order of alkali activation is a key factor to forecasting the mechanical behavior of alkali activated cement at different curing time and temperatures without carrying out experimental tests. The apparent activation energy was obtained as 35.6 kJ.mol-1 and 60.7 kJ.mol-1 for the two activators, respectively. Investigations proved that the alkali-activation kinetics of phosphorus slag resembles chemical reactions of second order. Moreover, the order of alkali-activation of phosphorus slag does not depend on the type of activator.

Effects of Alkali and Counter Ions in Sn-Beta Catalyzed Carbohydrate Conversion

DEFF Research Database (Denmark)

Elliot, Samuel G.; Tolborg, Søren; Madsen, Robert

2018-01-01

Alkali ions have been shown to strongly influence the catalytic behavior of stannosilicates in the conversion of carbohydrates. An effect of having alkali ions present is a pronounced increase in selectivity towards methyl lactate. Mechanistic details of this effect have remained obscure and are ......Alkali ions have been shown to strongly influence the catalytic behavior of stannosilicates in the conversion of carbohydrates. An effect of having alkali ions present is a pronounced increase in selectivity towards methyl lactate. Mechanistic details of this effect have remained obscure...... and are herein addressed experimentally through kinetic experiments and isotope tracking. Alkali ions have a differential effect in competing reaction pathways: they promote the rate of carbon-carbon bond breakage of carbohydrate substrates, but decrease the rates of competing dehydration pathways. Further...... addition of alkali inhibits activity of Sn-Beta in all major reaction pathways. The alkali effects on product distributions and on rates of product formation are similar, thus pointing to a kinetic reaction control and to irreversible reaction steps in the main pathways. Additionally, an effect...

Hybridizing pines with diluted pollen

Science.gov (United States)

Robert Z. Callaham

1967-01-01

Diluted pollens would have many uses by the tree breeder. Dilutions would be particularly advantageous in making many controlled pollinations with a limited amount of pollen. They also would be useful in artificial mass pollinations of orchards or single trees. Diluted pollens might help overcome troublesome genetic barriers to crossing. Feasibility o,f using diluted...

Acetic acid extraction from aqueous solutions using fatty acids

NARCIS (Netherlands)

IJmker, H.M.; Gramblicka, M.; Kersten, Sascha R.A.; van der Ham, Aloysius G.J.; Schuur, Boelo

2014-01-01

A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

Determination of the Thermodynamic Properties of Poly [2-(3-phenyl-3-methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] at Infinite Dilution by Inverse Gas Chromatography

OpenAIRE

KAYA, İsmet

2014-01-01

Some thermodynamic quantities were obtained for the interactions of poly [2-(3-phenyl -3- methylcyclobutyl)-2-hydroxyethyl methacrylate-co-methacrylic acid] Poly (PCHEMA-co-MA) with alcohols, ketones, acetates, aromatics and n-alkanes by inverse gas chromatography in the temperature range of 150-180oC. The specific retention volumes, Vgo, weight fraction activity coefficients of solute probes at infinite dilution, W1\\infty and Flory-Huggins thermodynamic interaction parameters, c12...

Optimization of Alkaline and Dilute Acid Pretreatment of Agave Bagasse by Response Surface Methodology

Science.gov (United States)

Ávila-Lara, Abimael I.; Camberos-Flores, Jesus N.; Mendoza-Pérez, Jorge A.; Messina-Fernández, Sarah R.; Saldaña-Duran, Claudia E.; Jimenez-Ruiz, Edgar I.; Sánchez-Herrera, Leticia M.; Pérez-Pimienta, Jose A.

2015-01-01

Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA) and alkaline (AL) catalyst providing specific effects on the physicochemical structure of the biomass, such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15%) since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification), which will be reflected in lower capital costs; however, this data is currently limited. In this study, several variables, such as catalyst loading, retention time, and solids loading, were studied using response surface methodology (RSM) based on a factorial central composite design of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w) to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS) yield. Pretreated biomass was characterized by wet-chemistry techniques and selected samples were analyzed by calorimetric techniques, and scanning electron/confocal fluorescent microscopy. RSM was also used to optimize the pretreatment conditions for maximum TRS yield. The optimum conditions were determined for AL pretreatment: 1.87% NaOH concentration, 50.3 min and 13.1% solids loading, whereas DA pretreatment: 2.1% acid concentration, 33.8 min and 8.5% solids loading. PMID:26442260

Magnetic properties of free alkali and transition metal clusters

International Nuclear Information System (INIS)

Heer, W. de; Milani, P.; Chatelain, A.

1991-01-01

The Stern-Gerlach deflections of small alkali clusters (N<6) and iron clusters (10< N<500) show that the paramagnetic alkali clusters always have a nondeflecting component, while the iron clusters always deflect in the high field direction. Both of these effects appear to be related to spin relaxation however in the case of alkali clusters it is shown that they are in fact caused by avoided level crossing in the Zeeman diagram. For alkali clusters the relatively weak couplings cause reduced magnetic moments where levels cross. For iron clusters however the total spin is strongly coupled to the molecular framework. Consequently this coupling is responsible for avoided level crossing which ultimately cause the total energy of the cluster to decrease with increasing magnetic field so that the iron clusters will deflect in one direction when introduced in an inhomogeneous magnetic field. Experiment and theory are discussed for both cases. (orig.)

Mechanisms of Retinal Damage after Ocular Alkali Burns.

Science.gov (United States)

Paschalis, Eleftherios I; Zhou, Chengxin; Lei, Fengyang; Scott, Nathan; Kapoulea, Vassiliki; Robert, Marie-Claude; Vavvas, Demetrios; Dana, Reza; Chodosh, James; Dohlman, Claes H

2017-06-01

Alkali burns to the eye constitute a leading cause of worldwide blindness. In recent case series, corneal transplantation revealed unexpected damage to the retina and optic nerve in chemically burned eyes. We investigated the physical, biochemical, and immunological components of retinal injury after alkali burn and explored a novel neuroprotective regimen suitable for prompt administration in emergency departments. Thus, in vivo pH, oxygen, and oxidation reduction measurements were performed in the anterior and posterior segment of mouse and rabbit eyes using implantable microsensors. Tissue inflammation was assessed by immunohistochemistry and flow cytometry. The experiments confirmed that the retinal damage is not mediated by direct effect of the alkali, which is effectively buffered by the anterior segment. Rather, pH, oxygen, and oxidation reduction changes were restricted to the cornea and the anterior chamber, where they caused profound uveal inflammation and release of proinflammatory cytokines. The latter rapidly diffuse to the posterior segment, triggering retinal damage. Tumor necrosis factor-α was identified as a key proinflammatory mediator of retinal ganglion cell death. Blockade, by either monoclonal antibody or tumor necrosis factor receptor gene knockout, reduced inflammation and retinal ganglion cell loss. Intraocular pressure elevation was not observed in experimental alkali burns. These findings illuminate the mechanism by which alkali burns cause retinal damage and may have importance in designing therapies for retinal protection. Copyright © 2017 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Spectroscopic and Kinetic Measurements of Alkali Atom-Rare Gas Excimers

Science.gov (United States)

2009-11-04

vapors – Exciplex molecules absorb over much greater bandwidth • Control of inherent high optical gain to minimize ASE and optimize laser oscillation... Exciplex assisted diode Pumped Alkali Laser (XPAL) • Education of a future generation of laser scientists VG09-227-2 Physical Sciences Inc. Novel Approach...This new laser exploits the optical properties of weakly-bound alkali/rare-gas exciplexes for pumping the 2P1/2, 3/2 alkali atomic excited states 4

Conduction bands and invariant energy gaps in alkali bromides

NARCIS (Netherlands)

Boer, P.K. de; Groot, R.A. de

1998-01-01

Electronic structure calculations of the alkali bromides LiBr, NaBr, KBr, RbBr and CsBr are reported. It is shown that the conduction band has primarily bromine character. The size of the band gaps of bromides and alkali halides in general is reinterpreted.

Alkali cyanides; destructive distillation

Energy Technology Data Exchange (ETDEWEB)

Clancy, J C

1925-12-02

The destructive distillation of carbonaceous substances can be accomplished by heating them in a bath of molten alkali and cyanide. Liquid hydrocarbons are produced. The separation of the cyanide from the coke or carbonaceous residues by filtration leaves a substantial quantity of cyanide absorbed by the carbon. A feasible method for removal has been developed by mixing the mixture of cyanide and coke with sodium carbonate or other alkali in the molten state, then treating this substance with nitrogen with or without ammonia to convert most of the carbon to cyanide. The carbonaceous material may be mixed with a liquid hydrocarbon such as petroleum, shale oil, or heavy tar oil, heated, and introduced below the surface of the liquid cyanide which partially decomposes and hydrogenates the coal to increase the yield of hydrocarbons. Dry ammonia may be bubbled through the reaction mixture to effect agitation and to form more cyanide.

Binding of chloride and alkalis in Portland cement systems

International Nuclear Information System (INIS)

Nielsen, Erik P.; Herfort, Duncan; Geiker, Mette R.

2005-01-01

A thermodynamic model for describing the binding of chloride and alkalis in hydrated Portland cement pastes has been developed. The model is based on the phase rule, which for cement pastes in aggressive marine environment predicts multivariant conditions, even at constant temperature and pressure. The effect of the chloride and alkalis has been quantified by experiments on cement pastes prepared from white Portland cements containing 4% and 12% C 3 A, and a grey Portland cement containing 7% C 3 A. One weight percent calcite was added to all cements. The pastes prepared at w/s ratio of 0.70 were stored in solutions of different Cl (CaCl 2 ) and Na (NaOH) concentrations. When equilibrium was reached, the mineralogy of the pastes was investigated by EDS analysis on the SEM. A well-defined distribution of chloride was found between the pore solution, the C-S-H phase, and an AFm solid solution phase consisting of Friedel's salt and monocarbonate. Partition coefficients varied as a function of iron and alkali contents. The lower content of alkalis in WPC results in higher chloride contents in the C-S-H phase. High alkali contents result in higher chloride concentrations in the pore solution

40 CFR 721.2565 - Alkylated sulfonated diphenyl oxide, alkali and amine salts.

Science.gov (United States)

2010-07-01

..., alkali and amine salts. 721.2565 Section 721.2565 Protection of Environment ENVIRONMENTAL PROTECTION... New Uses for Specific Chemical Substances § 721.2565 Alkylated sulfonated diphenyl oxide, alkali and... substances identified as alkylated sulfonated diphenyl oxide, alkali salt (PMN P-93-352) and alkylated...

Research and performance evaluation on an HA integrated acid system for sandstone acidizing

Directory of Open Access Journals (Sweden)

Liqiang Zhao

2018-03-01

Full Text Available When the conventional sandstone acidizing technologies are adopted, many slugs are needed in the injection of prepad fluid, treatment fluid and postpad fluid, and consequently the production and operation suffers inconveniences and difficulties. In view of this, a kind of HA integrated acid system which is mainly composed of organic polybasic acids (HA+HCl + HF and an efficient organic solvent was developed in this paper based on the idea of integrated acid replacing ''multiple steps'' and high efficiency and intensification. Via this HA integrated acid system, the complicated blockage in sandstone reservoirs can be removed effectively. Then, experiments were carried out on this system to evaluate its performance in terms of its retardance, organic blockage dissolution, chelating and precipitation inhibition. It is indicated that this new system can not only realize the acidizing of conventional integrated acid, but also present a good retarding performance by controlling H+ multi-stage ionization step by step and by forming silica acid-aluminum phosphonate film on the surface of clay minerals; that via this new HA integrated acid system, the organic blockage can be removed efficiently; and that it is wider in pH solution range than conventional APCs (aminopolycarboxyliates chelants, stronger in chelating capacity of Ca2+, Mg2+ and Fe3+ than conventional chelants (e.g. EDTA, NTA and DTPA, and better in precipitation inhibition on metal fluoride, fluosilicic acid alkali metal, fluoaluminic acid alkali metal and hydroxide than multi-hydrogen acid, fluoboric acid and mud acid systems. These research results provide a technical support for the plugging removal in high-temperature deep oil and gas reservoirs. Keywords: Organic polybasic acid, Integrated acid, Retardance, Chelating, Precipitation, Acidizing, Sandstone, Reservoir

Thermochemical properties of the alkali hydroxides: A review

International Nuclear Information System (INIS)

Konings, R.J.M.; Cordfunke, E.H.P.

1989-01-01

The formation of volatile alkali hydroxides as a result of high-temperature steam corrosion plays an important role in nuclear technology. For the modeling of the volatilization processes, reliable thermodynamic data are required. In the present paper recent physico-chemical experiments by the authors will be discussed and the thermochemical properties of the alkali hydroxide series will be evaluated. (orig.)

Possible applications of alkali-activated systems in construction

OpenAIRE

Boháčová, J.; Staněk, S.; Vavro, M. (Martin)

2013-01-01

This paper deals with the possibilities of using alkali-activated systems in construction. This article summarizes the advantages and disadvantages of geopolymer in comparison to Portland cement, summarizes research and practical applications of alkali-activated materials in our country and abroad, and provides an overview of directions where these alternative inorganic binders can be in the future very well applied.

Continuing studies of alkali-aggregate reactions in concrete

International Nuclear Information System (INIS)

Gilliot, J.E.; Beddoes, R.J.

1981-01-01

Studies are continuing into the nature of the different forms of the alkali-aggregate reaction. No general agreement exists as to the detailed nature of the expansive mechanisms. Alkali is known to react internally with opaline silica because of its microporous nature whereas reaction at the external surface is thought to be relatively more important in the case of quartz. A combination of Fourier shape and surface texture analysis, microscopy and osmotic studies is being used to obtain information on the relative importance of these two forms of alkaline attack on silica. Analytical methods are much more rapid than dimensional change tests and it is hoped that a better understanding of the expansion mechanism will lead to more certain recognition of potentially alkali expansive aggregates

The use of alkali-activated fly ash grouts for the remediation of AMD from underground mines

International Nuclear Information System (INIS)

Eaker, C.A.; Longley, R.D.; Michaud, L.H.; Silsbee, M.R.

1996-01-01

In preparation for a field demonstration, laboratory studies were conducted using several fly ash grout formulations to determine the optimum grout for an underground mine environment. This paper discusses the portion of the overall project designed to examine grout-acid mine drainage (AMD) interactions including neutralization, leaching and armoring of the grouts. Leaching tests were performed to study the effects of fly ash grout on AMD, including the effects of armoring. The goal of this project is to study the feasibility of in-situ acid mine drainage treatment by injecting alkali-activated fly ash grout into an underground mine

Waktu Dan Suhu Optimum Dalam Produksi Asam Oksalat (H2c2o4) Dari Limbah HVS Dengan Metode Peleburan Alkali

OpenAIRE

Nurul Nurul; St. Chadijah; Kurnia Ramadani

2017-01-01

Waste paper HVS can be used as raw material for the manufacture of oxalic acid containing 63 % cellulose. This study aims to determine the optimum time and temperature in the production of oxalic acid from waste paper with alkali fusion method. Oxalic acid can be made using an alkaline solution ( NaOH 40 % ) with multiple stages such as hydrolysis, filtration, precipitation with CaCl2, acidification with H2SO4 and efflorescence. The time variation used are 60, 70, 80 and 90 minutes. While the...

The effects of potassium and rubidium hydroxide on the alkali-silica reaction

International Nuclear Information System (INIS)

Shomglin, K.; Turanli, L.; Wenk, H.-R.; Monteiro, P.J.M.; Sposito, G.

2003-01-01

Expansion of mortar specimens prepared with an aggregate of mylonite from the Santa Rosa mylonite zone in southern California was studied to investigate the effect of different alkali ions on the alkali-silica reaction in concrete. The expansion tests indicate that mortar has a greater expansion when subjected to a sodium hydroxide bath than in a sodium-potassium-rubidium hydroxide bath. Electron probe microanalysis (EPMA) of mortar bars at early ages show that rubidium ions, used as tracer, were present throughout the sample by the third day of exposure. The analysis also shows a high concentration of rubidium in silica gel from mortar bars exposed to bath solutions containing rubidium. The results suggest that expansion of mortar bars using ASTM C 1260 does not depend on the diffusion of alkali ions. The results indicate that the expansion of alkali-silica gel depends on the type of alkali ions present. Alkali-silica gel containing rubidium shows a lower concentration of calcium, suggesting competition for the same sites

Properties of Hooked Steel Fibers Reinforced Alkali Activated Material Concrete

OpenAIRE

Faris M. A.; Abdullah Mohd Mustafa Al Bakri; Ismail Khairul Nizar; Muniandy Ratnasamy; Mahmad Nor Aiman; Putra Jaya Ramadhansyah; Waried Wazien A. Z.

2016-01-01

In this study, alkali activated material was produced by using Class F fly ash from Manjung power station, Lumut, Perak, Malaysia. Fly ash then was activated by alkaline activator which is consisting of sodium silicate (Na2SiO3) and sodium hydroxide (NaOH). Hooked end steel fibers were added into the alkali activated material system with percentage vary from 0 % – 5 %. Chemical compositions of fly ash were first analyzed by using x-ray fluorescence (XRF). All hardened alkali activated materia...

Behaviour of gaseous alkali compounds in coal gasification; Kaasumaisten alkaliyhdisteiden kaeyttaeytyminen kivihiilien kaasutuksessa

Energy Technology Data Exchange (ETDEWEB)

Nykaenen, J [Imatran Voima Oy, Vantaa (Finland)

1997-10-01

In this project the behaviour of alkali compounds emitting from CO{sub 2}/O{sub 2}- and airblown gasification are studied. This research project is closely connected to an EU-project coordinated by the Delft University of Technology (DUT). In that project alkali emissions from a 1.6 MW pilot plant will be measured. The results from those measurements will be compared with the calculations performed in this LIEKKI 2 project. The equilibrium calculations show that the major gaseous alkali compounds emitting from combustion and gasification are chlorides and hydroxides. This applies both to air- and CO{sub 2}/O{sub 2}-blown processes. In all the cases studied the concentration of gaseous alkali compounds is determined mainly by the amount of chlorides. The key parameters, with respect to alkali behaviour, are the temperature of the process and chlorine content of the coal. By cooling the gases down to 600 deg C prior to a ceramic filter the alkali concentration can be kept about at 100 ppbv. In combustion, the addition of calcium carbonate increases the amount of gaseous alkali compounds by decreasing the amount of alkali sulphates. In the case of gasification the importance of limestone is negligible. The difference between air- and CO{sub 2}/O{sub 2}-blown processes, in terms of gaseous alkali emissions, is small. This is because CO{sub 2} concentration of the gas does not have a strong impact on alkali chlorides. Furthermore, the effect of CO{sub 2}/O{sub 2}-ratio of the recirculation process is negligible. (orig.)

An on-line dilution system for spectrometry using an inductively coupled plasma source

International Nuclear Information System (INIS)

Moore, G.L.; Watson, A.E.; Humphries-Cuff, P.J.

1982-01-01

An on-line dilution system that uses a two-channel peristaltic pump to feed a GMK Babington type of nebulizer is described. By the use of a diluent containing the appropriate concentrations of acid, sodium, and internal standard element, which was fed at a constant rate to the nebulizer, the system produced analytical results that are not significantly different (less than 3 per cent relative) from those obtained with the normal dilution technique. However, a considerable saving in time is achieved, as well as a saving in the use of expensive reagents

Defluidization in fluidized bed gasifiers using high-alkali content fuels

DEFF Research Database (Denmark)

Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk

2016-01-01

samples,agglomeration could be attributed to viscous silicate melts formed from reaction of inorganic alkalineand alkali earth species with silica from the bed particles. A mathematical model that addresses the defluidization behavior of alkali-rich samples was developed based on the experiments performed...... and calcium, which may form viscous melts that adhere on the surface of the colliding bed particles and bind them to form agglomerates. In this paper, studies were made to understand the behavior of inorganic elements (mainly K, Si and Ca) on agglomeration and de-fluidization of alkali rich bed...... in the bench-scale fluidized bed reactor as well as on results from literature. The model was then used topredict the de-fluidization behavior of alkali-rich bed material in a large-scale LTCFB gasifier....

Bias due to Preanalytical Dilution of Rodent Serum for Biochemical Analysis on the Siemens Dimension Xpand Plus

Directory of Open Access Journals (Sweden)

Jennifer L. Johns

2018-02-01

Full Text Available Clinical pathology testing of rodents is often challenging due to insufficient sample volume. One solution in clinical veterinary and exploratory research environments is dilution of samples prior to analysis. However, published information on the impact of preanalytical sample dilution on rodent biochemical data is incomplete. The objective of this study was to evaluate the effects of preanalytical sample dilution on biochemical analysis of mouse and rat serum samples utilizing the Siemens Dimension Xpand Plus. Rats were obtained from end of study research projects. Mice were obtained from sentinel testing programs. For both, whole blood was collected via terminal cardiocentesis into empty tubes and serum was harvested. Biochemical parameters were measured on fresh and thawed frozen samples run straight and at dilution factors 2–10. Dilutions were performed manually, utilizing either ultrapure water or enzyme diluent per manufacturer recommendations. All diluted samples were generated directly from the undiluted sample. Preanalytical dilution caused clinically unacceptable bias in most analytes at dilution factors four and above. Dilution-induced bias in total calcium, creatinine, total bilirubin, and uric acid was considered unacceptable with any degree of dilution, based on the more conservative of two definitions of acceptability. Dilution often caused electrolyte values to fall below assay range precluding evaluation of bias. Dilution-induced bias occurred in most biochemical parameters to varying degrees and may render dilution unacceptable in the exploratory research and clinical veterinary environments. Additionally, differences between results obtained at different dilution factors may confound statistical comparisons in research settings. Comparison of data obtained at a single dilution factor is highly recommended.

Determination of gamma-aminobutyric acid in food matrices by isotope dilution hydrophilic interaction chromatography coupled to mass spectrometry.

Science.gov (United States)

Zazzeroni, Raniero; Homan, Andrew; Thain, Emma

2009-08-01

The estimation of the dietary intake of gamma-aminobutyric acid (GABA) is dependent upon the knowledge of its concentration values in food matrices. To this end, an isotope dilution liquid chromatography-mass spectrometry method has been developed employing the hydrophilic interaction chromatography technique for analyte separation. This approach enabled accurate quantification of GABA in apple, potato, soybeans, and orange juice without the need of a pre- or post-column derivatization reaction. A selective and precise analytical measurement has been obtained with a triple quadrupole mass spectrometer operating in multiple reaction monitoring using the method of standard additions and GABA-d(6) as an internal standard. The concentrations of GABA found in the matrices tested are 7 microg/g of apple, 342 microg/g of potatoes, 211 microg/g of soybeans, and 344 microg/mL of orange juice.

Spectra of alkali atoms

International Nuclear Information System (INIS)

Santoso, Budi; Arumbinang, Haryono.

1981-01-01

Emission spectra of alkali atoms has been determined by using spectrometer at the ultraviolet to infra red waves range. The spectra emission can be obtained by absorption spectrophotometric analysis. Comparative evaluations between experimental data and data handbook obtained by spark method were also presented. (author tr.)

Control of alkali species in gasification systems: Final report

Energy Technology Data Exchange (ETDEWEB)

Turn, S.; Kinoshita, C.; Ishimura, D. Zhou, J.; Hiraki, T.; Masutani, S.

2000-07-13

Gas-phase alkali metal compounds contribute to fouling, slagging, corrosion, and agglomeration problems in energy conversion facilities. One mitigation strategy applicable at high temperature is to pass the gas stream through a fixed bed sorbent or getter material, which preferentially absorbs alkali via physical adsorption or chemisorption. This report presents results of an experimental investigation of high-temperature alkali removal from a hot filtered gasifier product gas stream using a packed bed of sorbent material. Two getter materials, activated bauxite and emathlite, were tested at two levels of space time by using two interchangeable reactors of different internal diameters. The effect of getter particle size was also investigated.

Sputtering/redeposition analysis of alkali-based tungsten composites for limiter/divertor applications

International Nuclear Information System (INIS)

DeWald, A.B.; Krauss, A.R.; Gruen, D.M.; Valentine, M.G.

1986-07-01

Composites of porous tungsten infiltrated with alkali metal-bearing alloys have been projected as a means of reducing plasma impurities and sputter erosion in magnetic fusion devices. Self-sustaining alkali metal overlayers have been observed to inhibit erosion of the underlying structural substrate by 2X to 10X. The alkali metal itself, insofar as it sputters as a secondary ion, is trapped at the surface by sheath potential and tangential magnetic fields. Self-regeneration of the alkali metal coating is obtained by thermal and radiation-induced segregation from the bulk

Whole body acid-base modeling revisited.

Science.gov (United States)

Ring, Troels; Nielsen, Søren

2017-04-01

The textbook account of whole body acid-base balance in terms of endogenous acid production, renal net acid excretion, and gastrointestinal alkali absorption, which is the only comprehensive model around, has never been applied in clinical practice or been formally validated. To improve understanding of acid-base modeling, we managed to write up this conventional model as an expression solely on urine chemistry. Renal net acid excretion and endogenous acid production were already formulated in terms of urine chemistry, and we could from the literature also see gastrointestinal alkali absorption in terms of urine excretions. With a few assumptions it was possible to see that this expression of net acid balance was arithmetically identical to minus urine charge, whereby under the development of acidosis, urine was predicted to acquire a net negative charge. The literature already mentions unexplained negative urine charges so we scrutinized a series of seminal papers and confirmed empirically the theoretical prediction that observed urine charge did acquire negative charge as acidosis developed. Hence, we can conclude that the conventional model is problematic since it predicts what is physiologically impossible. Therefore, we need a new model for whole body acid-base balance, which does not have impossible implications. Furthermore, new experimental studies are needed to account for charge imbalance in urine under development of acidosis. Copyright © 2017 the American Physiological Society.

Optimization of alkaline and dilute acid pretreatment of agave bagasse by response surface methodology

Directory of Open Access Journals (Sweden)

Abimael I. Ávila-Lara

2015-09-01

Full Text Available Utilization of lignocellulosic materials for the production of value-added chemicals or biofuels generally requires a pretreatment process to overcome the recalcitrance of the plant biomass for further enzymatic hydrolysis and fermentation stages. Two of the most employed pretreatment processes are the ones that used dilute acid (DA and alkaline (AL catalyst providing specific effects on the physicochemical structure of the biomass such as high xylan and lignin removal for DA and AL, respectively. Another important effect that need to be studied is the use of a high solids pretreatment (≥15% since offers many advantaged over lower solids loadings, including increased sugar and ethanol concentrations (in combination with a high solids saccharification which will be reflected in lower capital costs, however this data is currently limited. In this study, several variables such as catalyst loading, retention time and solids loading, were studied using Response Surface Methodology (RSM based on a factorial Central Composite Design (CCD of DA and AL pretreatment on agave bagasse using a range of solids from 3 to 30% (w/w to obtain optimal process conditions for each pretreatment. Subsequently enzymatic hydrolysis was performed using Novozymes Cellic CTec2 and HTec2 presented as total reducing sugar (TRS yield. Pretreated biomass

Ultrafast electron dynamics at alkali/ice structures adsorbed on a metal surface

International Nuclear Information System (INIS)

Meyer, Michael

2011-01-01

The goal of this work is to study the interaction between excess electrons in water ice structures adsorbed on metal surfaces and other charged or neutral species, like alkali ions, or chemically reactive molecules, like chlorofluorocarbons (CFC), respectively. The excess electrons in the ice can interact with the ions directly or indirectly via the hydrogen bonded water molecules. In both cases the presence of the alkali influences the population, localization, and lifetime of electronic states of excess electrons in the ice adlayer. These properties are of great relevance when considering the highly reactive character of the excess electrons, which can mediate chemical reactions by dissociative electron attachment (DEA). The influence of alkali adsorption on electron solvation and transfer dynamics in ice structures is investigated for two types of adsorption configurations using femtosecond time-resolved two-photon photoelectron spectroscopy. In the first system alkali atoms are coadsorbed on top of a wetting amorphous ice film adsorbed on Cu(111). At temperatures between 60 and 100 K alkali adsorption leads to the formation of positively charged alkali ions at the ice/vacuum interface. The interaction between the alkali ions at the surface and the dipole moments of the surrounding water molecules results in a reorientation of the water molecules. As a consequence new electron trapping sites, i.e. at local potential minima, are formed. Photoinjection of excess electrons into these alkali-ion covered amorphous ice layers, results in the trapping of a solvated electron at an alkali-ion/water complex. In contrast to solvation in pure amorphous ice films, where the electrons are located in the bulk of the ice layer, solvated electrons at alkali-ion/water complexes are located at the ice/vacuum interface. They exhibit lifetimes of several picoseconds and show a fast energetic stabilization. With ongoing solvation, i.e. pump-probe time delay, the electron transfer is

Evaluation of xylitol production using corncob hemicellulosic hydrolysate by combining tetrabutylammonium hydroxide extraction with dilute acid hydrolysis.

Science.gov (United States)

Jia, Honghua; Shao, Tingting; Zhong, Chao; Li, Hengxiang; Jiang, Min; Zhou, Hua; Wei, Ping

2016-10-20

In this paper, we produced hemicellulosic hydrolysate from corncob by tetrabutylammonium hydroxide (TBAH) extraction and dilute acid hydrolysis combined, further evaluating the feasibility of the resultant corncob hemicellulosic hydrolysate used in xylitol production by Candida tropicalis. Optimized conditions for corncob hemicellulose extraction by TBAH was obtained via response surface methodology: time of 90min, temperature of 60°C, liquid/solid ratio of 12 (v/w), and TBAH concentration of 55%, resulting in a hemicellulose extraction of 80.07% under these conditions. The FT-IR spectrum of the extracted corncob hemicellulose is consistent with that of birchwood hemicellulose and exhibits specific absorbance of hemicelluloses at 1380, 1168, 1050, and 900cm(-1). In addition, we found that C. tropicalis can ferment the resulting corncob hemicellulosic hydrolysate with pH adjustment and activated charcoal treatment leading to a high xylitol yield and productivity of 0.77g/g and 2.45g/(Lh), respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of alkali metal ions on the pyrrole and pyridine π-electron systems in pyrrole-2-carboxylate and pyridine-2-carboxylate molecules: FT-IR, FT-Raman, NMR and theoretical studies

Science.gov (United States)

Świderski, G.; Wojtulewski, S.; Kalinowska, M.; Świsłocka, R.; Lewandowski, W.

2011-05-01

The FT-IR, FT-Raman and 1H and 13C NMR spectra of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium, rubidium and caesium pyrrole-2-carboxylates were recorded, assigned and compared in the Li → Na → K → Rb → Cs salt series. The effect of alkali metal ions on the electronic system of ligands was discussed. The obtained results were compared with previously reported ones for pyridine-2-carboxylic acid and alkali metal pyridine-2-carboxylates. Calculations for pyrrole-2-carboxylic acid and Li, Na, K pyrrole-2-carboxylates in B3LYP/6-311++G ** level and Møller-Plesset method in MP2/6-311++G ** level were made. Bond lengths, angles and dipole moments as well as aromaticity indices (HOMA, EN, GEO, I 6) for the optimized structures of pyrrole-2-carboxylic acid (PCA) and lithium, sodium, potassium pyrrole-2-carboxylates were also calculated. The degree of perturbation of the aromatic system of ligand under the influence of metals in the Li → Cs series was investigated with the use of statistical methods (linear correlation), calculated aromaticity indices and Mulliken, NBO and ChelpG population analysis method. Additionally, the Bader theory (AIM) was applied to setting the characteristic of the bond critical points what confirmed the influence of alkali metals on the pyrrole ring.

Effect of demineralization on the physiochemical structure and thermal degradation of acid treated indigenous rice husk

Directory of Open Access Journals (Sweden)

Aslam Umair

2016-09-01

Full Text Available Energy generation from biomass presents some serious problems like slagging, fouling and corrosion of boilers. To address these problems, demineralization of biomass is performed using different leaching agents. This study is focused on determining the influence of leaching agents and leaching time on the physiochemical structure of rice husk during demineralization. Dilute (5% wt solutions of HCl and H2SO4 were used for the demineralization of rice husk separately with leaching time of 15, 60 and 120 minutes. It is shown that H2SO4 exhibited higher removal of alkali and alkaline earth metals (AAEM comparatively as depicted by the 34.2% decrease in ash content along with an increase of 7.10% in the heating value. The acid has been seen to induce more notable changes in physiochemical structure as depicted by the FTIR spectra and SEM micrographs. The thermal degradation behavior of the demineralized rice husk has also been reported.

Process Design Report for Wood Feedstock: Lignocellulosic Biomass to Ethanol Process Desing and Economics Utilizing Co-Current Dilute Acid Prehydrolysis and Enzymatic Hydrolysis Current and Futuristic Scenarios

Energy Technology Data Exchange (ETDEWEB)

Wooley, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ruth, Mark [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sheehan, John [National Renewable Energy Lab. (NREL), Golden, CO (United States); Ibsen, Kelly [National Renewable Energy Lab. (NREL), Golden, CO (United States); Majdeski, Henry [Delta-T Corporation, Lexington, KY (United States); Galves, Adrian [Delta-T Corporation, Lexington, KY (United States)

1999-07-01

The National Renewable Energy Laboratory (NREL) has undertaken a complete review and update of the process design and economic model for the biomass-to-ethanol process based on co-current dilute acid prehydrolysis, along with simultaneous saccharification (enzymatic) and co-fermentation. The process design includes the core technologies being researched by the U.S. Department of Energy (DOE): prehydrolysis, simultaneous saccharification and co-fermentation, and cellulase enzyme production.

Synthesis of zeolite-like crystals by means of sorption of bases on polysilicic acids

Energy Technology Data Exchange (ETDEWEB)

Belyakova, L A; Il' in, V G; Peresun' ko, T F; Kryuchkova, I I; Neymark, I E [AN Ukrainskoj SSR, Kiev. Inst. Fizicheskoj Khimii

1974-11-21

Investigation into the sorption of bases on crystalline polysilicic acids is of particular interest from the viewpoint of synthesis of new types of porous zeolite-like materials. A synthesis of polysilicate acids was carried out by treating respective sodium polysilicates with mineral acid solutions. The sorption of alkali metal hydroxides in the neutral and alkaline pH region was studied by the method of potentiometric titration of individual weighed quantities. A marked sorption of alkali metal hydroxides on polysilicic acids starts in the weakly acid and neutral regions and reaches saturation at pH=10.5. The process of ion exchange is accompanied by a change in the crystal structure of polysilicic acids. The sorption of bases on polysilicic acids may be used as a method of synthesis of zeolite-like porous crystals in different cationic forms.

Synthesis of zeolite-like crystals by means of sorption of bases on polysilicic acids

International Nuclear Information System (INIS)

Belyakova, L.A.; Il'in, V.G.; Peresun'ko, T.F.; Kryuchkova, I.I.; Nejmark, I.E.

1974-01-01

Investigation into the sorption of bases on crystalline polysilicic acids is of particular interest from the viewpoint of synthesis of new types of porous zeolite-like materials. A synthesis of polysilicate acids was carried out by treating respective sodium polysilicates with mineral acid solutions. The sorption of alkali metal hydroxides in the neutral and alkaline pH region was studied by the method of potentiometric titration of individual weighed quantities. A marked sorption of alkali metal hydroxides on polysilicic acids starts in the weakly acid and neutral regions and reaches saturation at pHapproximately10.5. The process of ion exchange is accompanied by a change in the crystal structure of polysilicic acids. The sorption of bases on polysilicic acids may be used as a method of synthesis of zeolite-like porous crystals in different cationic forms

Language and Style in Zaynab Alkali's The Stillborn | Azuike ...

African Journals Online (AJOL)

This paper examines the language and style of Zaynab Alkali's The Stillborn. Alkali's style in The Stillborn lies in her effective deployment of linguo-literary resources to tell the story. The study scrutinizes the nexus of figures of speech and linguistic artifacts, which link the events and characters that populate her novel and ...

Missense mutation in exon 2 of SLC36A1 responsible for champagne dilution in horses.

Directory of Open Access Journals (Sweden)

Deborah Cook

2008-09-01

Full Text Available Champagne coat color in horses is controlled by a single, autosomal-dominant gene (CH. The phenotype produced by this gene is valued by many horse breeders, but can be difficult to distinguish from the effect produced by the Cream coat color dilution gene (CR. Three sires and their families segregating for CH were tested by genome scanning with microsatellite markers. The CH gene was mapped within a 6 cM region on horse chromosome 14 (LOD = 11.74 for theta = 0.00. Four candidate genes were identified within the region, namely SPARC [Secreted protein, acidic, cysteine-rich (osteonectin], SLC36A1 (Solute Carrier 36 family A1, SLC36A2 (Solute Carrier 36 family A2, and SLC36A3 (Solute Carrier 36 family A3. SLC36A3 was not expressed in skin tissue and therefore not considered further. The other three genes were sequenced in homozygotes for CH and homozygotes for the absence of the dilution allele (ch. SLC36A1 had a nucleotide substitution in exon 2 for horses with the champagne phenotype, which resulted in a transition from a threonine amino acid to an arginine amino acid (T63R. The association of the single nucleotide polymorphism (SNP with the champagne dilution phenotype was complete, as determined by the presence of the nucleotide variant among all 85 horses with the champagne dilution phenotype and its absence among all 97 horses without the champagne phenotype. This is the first description of a phenotype associated with the SLC36A1 gene.

Oxic limestone drains for treatment of dilute, acidic mine drainage

Science.gov (United States)

Cravotta, Charles A.

1998-01-01

Limestone treatment systems can be effective for remediation of acidic mine drainage (AMD) that contains moderate concentrations of dissolved O2 , Fe3+ , or A13+ (1‐5 mg‐L‐1 ). Samples of water and limestone were collected periodically for 1 year at inflow, outflow, and intermediate points within underground, oxic limestone drains (OLDs) in Pennsylvania to evaluate the transport of dissolved metals and the effect of pH and Fe‐ and Al‐hydrolysis products on the rate of limestone dissolution. The influent was acidic and relatively dilute (pH 1 mg‐L‐1 ) but was near neutral (pH = 6.2‐7.0); Fe and Al decreased to less than 5% of influent concentrations. As pH increased near the inflow, hydrous Fe and Al oxides precipitated in the OLDs. The hydrous oxides, nominally Fe(OH)3 and AI(OH)3, were visible as loosely bound, orange‐yellow coatings on limestone near the inflow. As time elapsed, Fe(OH)3 and AI(OH)3 particles were transported downflow. During the first 6 months of the experiment, Mn 2+ was transported conservatively through the OLDs; however, during the second 6 months, concentrations of Mn in effluent decreased by about 50% relative to influent. The accumulation of hydrous oxides and elevated pH (>5) in the downflow part of the OLDs promoted sorption and coprecipitation of Mn as indicated by its enrichment relative to Fe in hydrous‐oxide particles and coatings on limestone. Despite thick (~1 mm) hydrous‐oxide coatings on limestone near the inflow, CaCO3 dissolution was more rapid near the inflow than at downflow points within the OLD where the limestone was not coated. The rate of limestone dissolution decreased with increased residence time, pH, and concentrations of Ca2+ and HCO3‐ and decreased PCO2. The following overall reaction shows alkalinity as an ultimate product of the iron hydrolysis reaction in an OLD:Fe2+ + 0.25 O2 +CaCO3 + 2.5 H2O --> Fe(OH)3 + 2 Ca2+ + 2 HCO3-where 2 moles of CaCO3 dissolve for each mole of Fe(OH)3 produced

Use of Gelidium amansii as a promising resource for bioethanol: a practical approach for continuous dilute-acid hydrolysis and fermentation.

Science.gov (United States)

Park, Jeong-Hoon; Hong, Ji-Yeon; Jang, Hyun Chul; Oh, Seung Geun; Kim, Sang-Hyoun; Yoon, Jeong-Jun; Kim, Yong Jin

2012-03-01

A facile continuous method for dilute-acid hydrolysis of the representative red seaweed species, Gelidium amansii was developed and its hydrolysate was subsequently evaluated for fermentability. In the hydrolysis step, the hydrolysates obtained from a batch reactor and a continuous reactor were systematically compared based on fermentable sugar yield and inhibitor formation. There are many advantages to the continuous hydrolysis process. For example, the low melting point of the agar component in G. amansii facilitates improved raw material fluidity in the continuous reactor. In addition, the hydrolysate obtained from the continuous process delivered a high sugar and low inhibitor concentration, thereby leading to both high yield and high final ethanol titer in the fermentation process. Copyright © 2011 Elsevier Ltd. All rights reserved.

A procedure for preparing alkali metal hydrides

International Nuclear Information System (INIS)

Lemieux, R.U.; Sanford, C.E.; Prescott, J.F.

1976-01-01

A plain low cost, procedure for the continuous, low temperature preparation of sodium or potassium hydrides using cheap reagents is presented. Said invention is especially concerned with a process of purifying of a catalytic exchange liquid used for deuterium enrichment, in which an alkali metal hydride is produced as intermediate product. The procedure for producing the sodium and potassium hydrides consists in causing high pressure hydrogen to be absorbed by a mixture of at least a lower monoalkylamine and an alkylamide of an alkali metal from at least one of said amines [fr

Density functional study of ferromagnetism in alkali metal thin films

Indian Academy of Sciences (India)

thickness uniform jellium model (UJM), and it is argued that within LSDA or GGA, alkali metal thin films cannot be claimed to have an FM ground state. Relevance of these results to the experiments on transition metal-doped alkali metal thin films ...

Neuropsychiatric manifestations of alkali metal deficiency and excess

Energy Technology Data Exchange (ETDEWEB)

Yung, C.Y.

1984-01-01

The alkali metals from the Group IA of the periodic table (lithium, sodium, potassium, rubidium, cesium and francium) are reviewed. The neuropsychiatric aspects of alkali metal deficiencies and excesses (intoxications) are described. Emphasis was placed on lithium due to its clinical uses. The signs and symptoms of these conditions are characterized by features of an organic brain syndrome with delirium and encephalopathy prevailing. There are no clinically distinctive features that could be reliably used for diagnoses. Sodium and potassium are two essential alkali metals in man. Lithium is used as therapeutic agent in bipolar affective disorders. Rubidium has been investigated for its antidepressant effect in a group of psychiatric disorders. Cesium is under laboratory investigation for its role in carcinogenesis and in depressive illness. Very little is known of francium due to its great instability for experimental study.

Structural Investigation of Alkali Activated Clay Minerals for Application in Water Treatment Systems

Science.gov (United States)

Bumanis, G.; Bajare, D.; Dembovska, L.

2015-11-01

Alkali activation technology can be applied for a wide range of alumo-silicates to produce innovative materials with various areas of application. Most researches focuse on the application of alumo-silicate materials in building industry as cement binder replacement to produce mortar and concrete [1]. However, alkali activation technology offers high potential also in biotechnologies [2]. In the processes where certain pH level, especially alkaline environment, must be ensured, alkali activated materials can be applied. One of such fields is water treatment systems where high level pH (up to pH 10.5) ensures efficient removal of water pollutants such as manganese [3]. Previous investigations had shown that alkali activation technology can be applied to calcined clay powder and aluminium scrap recycling waste as a foam forming agent to create porous alkali activated materials. This investigation focuses on the structural investigation of calcined kaolin and illite clay alkali activation processes. Chemical and mineralogical composition of both clays were determined and structural investigation of alkali activated materials was made by using XRD, DTA, FTIR analysis; the microstructure of hardened specimens was observed by SEM. Physical properties of the obtained material were determined. Investigation indicates the essential role of chemical composition of the clay used in the alkali activation process, and potential use of the obtained material in water treatment systems.

Impact of acid and alkaline pretreatments on the molecular network of wheat gluten and on the mechanical properties of compression-molded glassy wheat gluten bioplastics.

Science.gov (United States)

Jansens, Koen J A; Lagrain, Bert; Brijs, Kristof; Goderis, Bart; Smet, Mario; Delcour, Jan A

2013-10-02

Wheat gluten can be converted into rigid biobased materials by high-temperature compression molding at low moisture contents. During molding, a cross-linked protein network is formed. This study investigated the effect of mixing gluten with acid/alkali in 70% ethanol at ambient temperature for 16 h followed by ethanol removal, freeze-drying, and compression molding at 130 and 150 °C on network formation and on types of cross-links formed. Alkaline pretreatment (0-100 mmol/L sodium hydroxide or 25 mmol/L potassium hydroxide) strongly affected gluten cross-linking, whereas acid pretreatment (0-25 mmol/L sulfuric acid or 25 mmol/L hydrochloric acid) had limited effect on the gluten network. Molded alkaline-treated gluten showed enhanced cross-linking but also degradation when treated with high alkali concentrations, whereas acid treatment reduced gluten cross-linking. β-Elimination of cystine and lanthionine formation occurred more pronouncedly at higher alkali concentrations. In contrast, formation of disulfide and nondisulfide cross-links during molding was hindered in acid-pretreated gluten. Bioplastic strength was higher for alkali than for acid-pretreated samples, whereas the flexural modulus was only slightly affected by either alkaline or acid pretreatment. Apparently, the ratio of disulfide to nondisulfide cross-links did not affect the mechanical properties of rigid gluten materials.

Structural, elastic, electronic and optical properties of bi-alkali ...

Indian Academy of Sciences (India)

The structural parameters, elastic constants, electronic and optical properties of the bi-alkali ... and efficient method for the calculation of the ground-state ... Figure 2. Optimization curve (E–V) of the bi-alkali antimonides: (a) Na2KSb, (b) Na2RbSb, (c) Na2CsSb, .... ical shape of the charge distributions in the contour plots.

Phytanic acid alpha-oxidation: accumulation of 2-hydroxyphytanic acid and absence of 2-oxophytanic acid in plasma from patients with peroxisomal disorders

NARCIS (Netherlands)

ten Brink, H. J.; Schor, D. S.; Kok, R. M.; Poll-The, B. T.; Wanders, R. J.; Jakobs, C.

1992-01-01

A stable isotope dilution method was developed for the measurement of 2-hydroxyphytanic acid and 2-oxophytanic acid in plasma. In plasma from healthy individuals and from patients with Refsum's disease, 2-hydroxyphytanic acid was found at levels less than 0.2 mumol/l, whereas the acid accumulated in

Photoemission spectroscopy study of a multi-alkali photocathode

CERN Document Server

Ettema, A R H

2000-01-01

In this paper a photoemission study of the highest core levels of the elements and the electron escape barrier (work function) in a multi-alkali photocathode are presented. The core levels indicate that the alkali atoms are in an oxidized state and therefore the compound Na sub 2 KSb can be regarded as an ionic semiconductor. The measured escape barrier of the Cs sub 2 O surface layer is determined as 2.3 eV.

Effects of alkali and steaming on mechanical properties of snake fruit (Salacca) fiber

Science.gov (United States)

Darmanto, Seno; Rochardjo, Heru S. B.; Jamasri, Widyorini, Ragil

2017-01-01

The aim of this research is to investigate the effect of alkali treatment and steaming on mechanical properties of Snake Fruit frond fiber. The presence of surface impurities and a lot of hydroxyl groups makes natural fiber less compatible for composite materials reinforcement. Efforts to remove the impurities can be done by physical, chemical and mechanical treatments. This paper reports the treatment of Snake Fruit frond single fiber by subjecting it to alkali treatments with 2%- 8% NaOH for 2 - 6 hours at room temperature. The treatment is then followed by steaming at a pressure of 2 bars in 1 hour. Results show that the treatment of alkali and the alkali-steaming combination can increase cellulose percentage. The tensile tests show that this type of treatment in combination resulted in the higher tensile strength compared to untreated fiber. There is a significant increase in tensile strength with increasing alkali percentage. However, the further increase in the percentage of alkali solution will result in decreasing tensile strength. The highest value of tensile strength after treatment was 275 MPa with 6 hours treatment at alkali percentage of 2 %.

Structure of xanthan gum and cell ultrastructure at different times of alkali stress.

Science.gov (United States)

Luvielmo, Márcia de Mello; Borges, Caroline Dellinghausen; Toyama, Daniela de Oliveira; Vendruscolo, Claire Tondo; Scamparini, Adilma Regina Pippa

2016-01-01

The effect of alkali stress on the yield, viscosity, gum structure, and cell ultrastructure of xanthan gum was evaluated at the end of fermentation process of xanthan production by Xanthomonas campestris pv. manihotis 280-95. Although greater xanthan production was observed after a 24h-alkali stress process, a lower viscosity was observed when compared to the alkali stress-free gum, regardless of the alkali stress time. However, this outcome is not conclusive as further studies on gum purification are required to remove excess sodium, verify the efficiency loss and the consequent increase in the polymer viscosity. Alkali stress altered the structure of xanthan gum from a polygon-like shape to a star-like form. At the end of the fermentation, early structural changes in the bacterium were observed. After alkali stress, marked structural differences were observed in the cells. A more vacuolated cytoplasm and discontinuities in the membrane cells evidenced the cell lysis. Xanthan was observed in the form of concentric circles instead of agglomerates as observed prior to the alkali stress. Copyright © 2015 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

The influence of polycarboxylate-type super-plasticizers on alkali-free liquid concrete accelerators performance

Science.gov (United States)

Guo, Wenkang; Yin, Haibo; Wang, Shuyin; He, Zhifeng

2017-04-01

Through studying on the setting times, cement mortar compressive strength and cement mortar compressive strength ratio, the influence of alkali-free liquid accelerators polycarboxylate-type super-plasticizers on the performance of alkali-free liquid accelerators in cement-based material was investigated. The results showed that the compatibility of super-plasticizers and alkali-free liquid accelerators was excellent. However, the dosage of super-plasticizers had a certain impact on the performance of alkali-free liquid accelerators as follows: 1) the setting times of alkali-free liquid accelerators was in the inverse proportional relationship to the dosage of super-plasticizers; 2)the influence of super-plasticizers dosage on the cement mortar compressive strength of alkali-free liquid accelerators was related to the types of accelerators, where exist an optimum super-plasticizers dosage for cement mortar compressive strength at 28d; 3)the later cement mortar compressive strength with alkali-free liquid accelerators were decreasing with the increment of the super-plasticizers dosage. In the practical application of alkali-free liquid accelerators and super-plasticizer, the dosage of super-plasticizer must be determined by dosage optimization test results.

Decalcification resistance of alkali-activated slag

Energy Technology Data Exchange (ETDEWEB)

Komljenovic, Miroslav M., E-mail: miroslav.komljenovic@imsi.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Bascarevic, Zvezdana, E-mail: zvezdana@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Marjanovic, Natasa, E-mail: natasa@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia); Nikolic, Violeta, E-mail: violeta@imsi.bg.ac.rs [Institute for Multidisciplinary Research, University of Belgrade, Kneza Viseslava 1, 11030 Belgrade (Serbia)

2012-09-30

Highlights: Black-Right-Pointing-Pointer The effects of decalcification on properties of alkali-activated slag were studied. Black-Right-Pointing-Pointer Decalcification was performed by concentrated NH{sub 4}NO{sub 3} solution (accelerated test). Black-Right-Pointing-Pointer Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Black-Right-Pointing-Pointer Decalcification led to strength decrease and noticeable structural changes. Black-Right-Pointing-Pointer Alkali-activated slag showed significantly higher resistance to decalcification. - Abstract: This paper analyses the effects of decalcification in concentrated 6 M NH{sub 4}NO{sub 3} solution on mechanical and microstructural properties of alkali-activated slag (AAS). Portland-slag cement (CEM II/A-S 42.5 N) was used as a benchmark material. Decalcification process led to a decrease in strength, both in AAS and in CEM II, and this effect was more pronounced in CEM II. The decrease in strength was explicitly related to the decrease in Ca/Si atomic ratio of C-S-H gel. A very low ratio of Ca/Si {approx}0.3 in AAS was the consequence of coexistence of C-S-H(I) gel and silica gel. During decalcification of AAS almost complete leaching of sodium and tetrahedral aluminum from C-S-H(I) gel also took place. AAS showed significantly higher resistance to decalcification in relation to the benchmark CEM II due to the absence of portlandite, high level of polymerization of silicate chains, low level of aluminum for silicon substitution in the structure of C-S-H(I), and the formation of protective layer of polymerized silica gel during decalcification process. In stabilization/solidification processes alkali-activated slag represents a more promising solution than Portland-slag cement due to significantly higher resistance to decalcification.

[Using a modified remote sensing imagery for interpreting changes in cultivated saline-alkali land].

Science.gov (United States)

Gao, Hui; Liu, Hui-tao; Liu, Hong-juan; Liu, Jin-tong

2015-04-01

This paper developed a new interpretation symbol system for grading and classifying saline-alkali land, using Huanghua, a cosatal city in Hebei Province as a case. The system was developed by inverting remote sensing images from 1992 to 2011 based on site investigation, plant cover characteristics and features of remote sensing images. Combining this interpretation symbol system with supervising classification method, the information on arable land was obtained for the coastal saline-alkali ecosystem of Huanghua City, and the saline-alkali land area, changes in intensity of salinity-alkalinity and spatial distribution from 1992 to 2011 were analyzed. The results showed that salinization of arable land in Huanghua City alleviated from 1992 to 2011. The severely and moderately saline-alkali land area decreased in 2011 compared with 1992, while the non/slightly saline land area increased. The moderately saline-alkali land in southeast transformed to non/slightly saline-alkaline, while the severely saline-alkali land in west of the city far from the coastal zone became moderately saline-alkaline. The center of gravity (CG) of severely and non/slightly saline-alkali land moved closer the coastline, while that of the moderately saline-alkali land moved from southwest coastal line to northwest. Factors influencing changes in arable land within the saline-alkali ecosystem of Huanghua City were climate, hydrology and human activities.

Influence of alkali metal cations/type of activator on the structure of alkali-activated fly ash - ATR-FTIR studies

Science.gov (United States)

Król, M.; Rożek, P.; Chlebda, D.; Mozgawa, W.

2018-06-01

Coal fly ash as a secondary aluminosiliceous raw material that is commonly used in the so-called geopolymerization process has been activated with different alkali hydroxides solutions: LiOH, NaOH and KOH. Changes in the aluminosilicate structure of the material during alkali-activation have been analyzed in detail on the basis of ATR/FT-IR spectra. These changes mainly affect both the integral intensity and FWHM of bands in the range of 1200-950 cm-1, however dehydration and carbonation process can be also analyzed based on obtaining results.

Performance and techno-economic assessment of several solid-liquid separation technologies for processing dilute-acid pretreated corn stover.

Science.gov (United States)

Sievers, David A; Tao, Ling; Schell, Daniel J

2014-09-01

Solid-liquid separation of pretreated lignocellulosic biomass slurries is a critical unit operation employed in several different processes for production of fuels and chemicals. An effective separation process achieves good recovery of solute (sugars) and efficient dewatering of the biomass slurry. Dilute acid pretreated corn stover slurries were subjected to pressure and vacuum filtration and basket centrifugation to evaluate the technical and economic merits of these technologies. Experimental performance results were used to perform detailed process simulations and economic analysis using a 2000 tonne/day biorefinery model to determine differences between the various filtration methods and their process settings. The filtration processes were able to successfully separate pretreated slurries into liquor and solid fractions with estimated sugar recoveries of at least 95% using a cake washing process. A continuous vacuum belt filter produced the most favorable process economics. Copyright © 2014 Elsevier Ltd. All rights reserved.

One-step pretreatment of yellow poplar biomass using peracetic acid to enhance enzymatic digestibility.

Science.gov (United States)

Lee, Hyeong Rae; Kazlauskas, Romas J; Park, Tai Hyun

2017-09-22

Pretreatment of biomass with dilute acid requires high temperatures of >160 °C to remove xylan and does not remove lignin. Here we report that the addition of peracetic acid, a strong oxidant, to mild dilute acid pretreatment reduces the temperature requirement to only 120 °C. Pretreatment of yellow poplar with peracetic acid (300 mM, 2.3 wt%) and dilute sulfuric acid (100 mM, 1.0 wt%) at 120 °C for 5 min removed 85.7% of the xylan and 90.4% of the lignin leaving a solid consisting of 75.6% glucan, 6.0% xylan and 4.7% lignin. Low enzyme loadings of 5 FPU/g glucan and 10 pNPGU/g glucan converted this solid to glucose with an 84.0% yield. This amount of glucose was 2.5 times higher than with dilute acid-pretreated solid and 13.8 times higher than with untreated yellow poplar. Thus, the addition of peracetic acid, easily generated from acetic acid and hydrogen peroxide, dramatically increases the effectiveness of dilute acid pretreatment of biomass.

Alkali content of fly ash : measuring and testing strategies for compliance : [tech transfer summary].

Science.gov (United States)

2015-04-01

This study investigated the test methods used to determine the : alkali content of fly ash. It also evaluated if high-alkali fly ash : exacerbates alkali-silica reaction in laboratory tests and field : concrete.

Experimental investigation of aqueous corrosion of R7T7 nuclear glass at 90 degrees C in the presence of humic acids: A kinetic approach

International Nuclear Information System (INIS)

Gin, S.; Godon, N.; Mestre, J.P.; Vernaz, E.Y.; Beaufort, D.

1994-01-01

The dissolution kinetics of the French open-quotes R7T7close quotes nonradioactive LWR reference glass in solutions containing dissolved humic acids were investigated at 9O degrees C during static tests with imposed or free pH. Experiments conducted in highly dilute media, with a glass-surface-area-to-solution-volume (SA/V) ratio of 5 m -1 , showed that the glass dissolution surface reaction is catalyzed by humic acids. With higher degrees of reaction progress (SA/V = 100 m -1 and free pH) the humic acids impose pH modifications on the system compared with inorganic media; moreover, they directly or indirectly enhance the dissolution of certain alkali metals and transition elements, forming aqueous complexes with the latter. During experiments with an imposed pH of 8.5 (SA/V = 1300 and 5300 m -1 ), the humic acids appear to cause increased silica solubility that cannot be accounted for by the formation of silica complexes. A residual corrosion rate in the humic acid media exceeding the rate measured in inorganic media suggests that, in addition to silica, one or more element complexes formed by humic acids may be a kinetically limiting factor. This hypothesis must be confirmed, however, as the quantity of humic acids per unit glass surface area was too small in this experiment to allow unambiguous characterization of the phenomenon

Boric acid solubility in the presence of alkali metal nitrides

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Tsekhanskij, R S; Molodkin, A K; Sadetdinov, Sh V [Chuvashskij Gosudarstvennyj Univ., Cheboksary (USSR); Universitet Druzhby Narodov, Moscow (USSR))

1983-01-01

Methods of solubility and refractometry at 25 deg C have been applied to state that systems boric acid-lithium (sodium, potassium) nitrite-water are simple eutonic type systems. Nitrites salt in the acid and their lyotropic effect increases from lithium salt to potassium salt. The disclosed succession in change of the effect is determined by the character of cation hydration in the medium the acidic reaction of which is conditioned by boric acid polymerization and partial oxidation of nitrite ion into nitrate ion. Boric acid is salted out from solutions containing lithium and sodium cations with increase of nitrate ion.

Boric acid solubility in the presence of alkali metal nitrides

International Nuclear Information System (INIS)

Skvortsov, V.G.; Tsekhanskij, R.S.; Molodkin, A.K.; Sadetdinov, Sh.V.

1983-01-01

Methods of solubility and refractometry at 25 deg C have been applied to state that systems boric acid-lithium (sodiUm, potassium) nitrite-water are simple eutonic type systems. Nitrites salt in the acid and their lyotropic effect increases from lithium salt to potassium salt. The disclosed succession in change of the effect is determined by the character of cation hydration in the medium the acidic reaction of which is conditioned by boric acid polymerization and partial oxidation of nitrite ion into nitrate ion Boric acid is salted out form solutions containing lithium and sodium cations with increase of nitrate ion

Influence of alkali metal hydroxides on corrosion of Zr-base alloys

International Nuclear Information System (INIS)

Jeong, Yong Hwan

1996-01-01

The influence of group-1 alkali hydroxides on different Zr-based alloys have been carried out in static autoclaves at 350 deg C in pressurized water, conditioned in low(0.32 mmol), medium(4.3 mmol) and high(31.5 mmol) equimolar concentration of Li-, Na-, K-, Rb- and Cs-hydroxide. Two types of alloys have been investigated: Zr-Sn-(TRM, Transition metal) and Zr-Sn-Nb-(TRM, Transition metal). From the experiments the cation could be identified as the responsible species for corrosion of Zr alloy in alkalized water. The radius of the cation governs the accelerated corrosion in the pre-transition region of Zr alloy. Incorporation of alkali cation into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significant lower effect for the other bases. Nb containing alloys showed lower corrosion resistance than Zr-Sn-TRM alloys in all alkali solutions. Both types of alloys were corroded significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behavior in the different alkali environments and taking into account the tendency to accelerate the corrosion of Zr alloys, CsOH and KOH are possible alternate alkali for PWR (Pressurized Water Reactor) application. (author)

Solution mining process

International Nuclear Information System (INIS)

Showalter, W.E.

1984-01-01

A solution mining process which may be used for uranium, thorium, vanadium, copper, nickel, molybdenum, rhenium, and selenium is claimed. During a first injection-and-production phase of between 6 months and 5 years, a leaching solution is injected through at least one well into the formation to solubilize the mineral values and form a pregnant liquor. This liquor is recovered through another well. The leaching solution contains sulfuric acid, nitric acid, hydrochloric acid, carbonic acid, an alkali metal carbonate, an alkali metal bicarbonate, ammonium carbonate or ammonium bicarbonate. Subsequently during a first production-only phase of between about 2 weeks and one year, injection of the leaching solution is suspended but pregnant liquor is still recovered. This stage is followed by a second injection-and-production phase of between 6 months and 5 years and a second production-only phase. The mineral values are separated from the pregnant liquor to form a barren liquor. The leaching agent is introduced into this liquor, and the solution is recycled. In a second claim for the solution mining of uranium, dilute carbonic acid is used as the leaching solution. The solution has a pH less than 7 and a bicarbonate ion concentration between about 380 ppm and 1000 ppm. The injection-and-production phase lasts between one and two years and the production only phase takes between one and four months. Carbon dioxide is introduced into the barren liquor to form a dilute carbonic acid solution and the solution is recycled

Solubility of 1:1 Alkali Nitrates and Chlorides in Near-Critical and Supercritical Water : 1 Alkali Nitrates and Chlorides in Near-Critical and Supercritical Water

NARCIS (Netherlands)

Leusbrock, Ingo; Metz, Sybrand J.; Rexwinkel, Glenn; Versteeg, Geert F.

2009-01-01

To increase the available data oil systems containing supercritical water and inorganic compounds, all experimental setup was designed to investigate the solubilities of inorganic compounds Ill supercritical water, In this work, three alkali chloride salts (LiCl, NaCl, KCl) and three alkali nitrate

Alkali Release from Typical Danish Aggregates to Potential ASR Reactive Concrete

DEFF Research Database (Denmark)

Thomsen, Hans Christian Brolin; Grelk, Bent; Barbosa, Ricardo Antonio

Alkali-silica reaction (ASR) in concrete is a well-known deterioration mechanism affecting the long term durability of Danish concrete structures. Deleterious ASR cracking can be significantly reduced or prevented by limiting the total alkali content of concrete under a certain threshold limit......, which in Denmark is recommended to 3 kg/m3 Na2Oeq.. However, this threshold limit does not account for the possible internal contribution of alkali to the concrete pore solution by release from aggregates or external contributions from varies sources. This study indicates that certain Danish aggregates...... are capable of releasing more than 0.46 kg/m3 Na2Oeq. at 13 weeks of exposure in laboratory test which may increase the risk for deleterious cracking due to an increase in alkali content in the concrete....

An alkali ion source based on graphite intercalation compounds for ion mobility spectrometry

International Nuclear Information System (INIS)

Tabrizchi, Mahmoud; Hosseini, Zahra S

2008-01-01

A variety of alkali cation emitters were developed as the ion source for ion mobility spectrometry. The cation emitters were constructed based on alkali ion graphite intercalation compounds (GICs). The compounds were prepared by fusing alkali salts with ground graphite. In order to produce alkali ions, the compounds were loaded on a filament and heated to red. Reactant ions of the form alk + ions were observed for the alkali salts NaCl, KCl.LiCl, CsCl and SrCl. In addition to Na + ions, K + ions were observed at the beginning of thermionic emission from Na-GIC. This is due to the low ionization potential of potassium that exists in trace amounts in sodium salts. In addition to the potassium ion, Na + was observed in the case of LiCl salt. The Na + and K + peaks originating from impurities totally disappeared after about 40 min. However, the thermionic emission of the main ion of the corresponding salt lasted for several days. No negative ions were observed upon reversing the drift field. Selected organic compounds (methyl isobutyl ketone, dimethyl sulfoxide, acetone and tetrahydrofuran) were also ionized via alkali cation attachment reaction. Distinct ion mobility patterns were observed for different substances using one type of alkali reactant ion. However, the ion mobility pattern for a given substance changed when a different alkali reactant ion was used. Ammonia and amines were not ionized when this source was used

Alternative alkali resistant deNOx catalysts

DEFF Research Database (Denmark)

Putluru, Siva Sankar Reddy; Kristensen, Steffen Buus; Due-Hansen, Johannes

2012-01-01

by onepot sol–gel method. All catalysts were characterized by BET, XRPD and NH3-TPD. Initial SCR activities of 8 out of 9 catalysts showed higher NO conversion at least at one temperature in the temperature range 300–500 ◦C compared to the conventional V2O5-WO3/TiO2 catalyst. After potassium poisoning (100......Alternative alkali resistant deNOx catalysts were prepared using three different supports ZrO2, TiO2 and Mordenite zeolite. The majority of the catalysts were prepared by incipient wetness impregnation of a commercial support, with vanadium, copper or iron precursor, one catalyst was prepared......–130 µmol of K/g of catalyst) the relative drop in SCR activity and acidity was lower for all the alternative catalysts compared to the industrial V2O5-WO3/TiO2 catalyst. Furthermore, Cu/MOR and Nano-V2O5/Sul-TiO2 catalysts showed 8–16 times higher SCR activities than the conventional even after high...

Radiation degradation and the consequent decrease in the efficacy of some dilute chemical decontaminant formulations

Energy Technology Data Exchange (ETDEWEB)

Kamal Kishore; Dey, G.R.; Naik, D.B.; Moorthy, P.N. [Applied Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 (India)

1998-12-31

Constituents of dilute chemical decontaminant formulations such as ascorbic acid, EDTA, picolinic acid (PA) and 2,6-pyridine dicarboxylic acid (PDCA), also known as dipicolinic acid, are highly reactive with primary species produced from water radiolysis. Picolinic acid and PDCA however, are less sensitive to radiation dose due to their aromatic nature. They also help in protecting ascorbic acid when in a mixture. The efficacy for dissolution of magnetite was found to reduce drastically on irradiation in the case of EDTA/oxalic acid/citric acid while it was unaffected in the case of picolinic acid/ascorbic acid. In the case of EDTA/ascorbic acid/citric acid or PDCA/ascorbic acid formulations, there was only a marginal effect of radiation on the efficacy of the formulations. (author)

Effect of pretreatment severity on accumulation of major degradation products from dilute acid pretreated corn stover and subsequent inhibition of enzymatic hydrolysis of cellulose.

Science.gov (United States)

Um, Byung-Hwan; van Walsum, G Peter

2012-09-01

The concept of reaction severity, which combines residence time and temperature, is often used in the pulp and paper and biorefining industries. The influence of corn stover pretreatment severity on yield of sugar and major degradation products and subsequent effects on enzymatic cellulose hydrolysis was investigated. The pretreatment residence time and temperature, combined into the severity factor (Log R(o)), were varied with constant acid concentration. With increasing severity, increasing concentrations of furfural and 5-hydroxymethylfurfural (5-HMF) coincided with decreasing yields of oligosaccharides. With further increase in severity factor, the concentrations of furans decreased, while the formation of formic acid and lactic acid increased. For example, from severity 3.87 to 4.32, xylose decreased from 6.39 to 5.26 mg/mL, while furfural increased from 1.04 to 1.33 mg/mL; as the severity was further increased to 4.42, furfural diminished to 1.23 mg/mL as formate rose from 0.62 to 1.83 mg/mL. The effects of dilute acid hydrolyzate, acetic acid, and lignin, in particular, on enzymatic hydrolysis were investigated with a rapid microassay method. The microplate method gave considerable time and cost savings compared to the traditional assay protocol, and it is applicable to a broad range of lignocellulosic substrates.

Carbohydrates, uronic acids and alkali extractable carbohydrates in contrasting marine and estuarine sediments: Distribution, size fractionation and partial chemical characterization

Digital Repository Service at National Institute of Oceanography (India)

Khodse, V.B.; Fernandes, L.; Bhosle, N.B.; Sardessai, S.

terrestrial plants, bacteria and phytoplankton, however, the influence of the former was relatively greater in sediments of the ME and BOB, as well as in residual sediments of ME. Approximately 11-21% of total carbohydrates could be extracted using hot alkali...

Accurate determination and certification of bromine in plastic by isotope dilution inductively coupled plasma mass spectrometry

International Nuclear Information System (INIS)

Ohata, Masaki; Miura, Tsutomu

2014-01-01

Highlights: • Accurate analytical method of Br in plastic was studied by isotope dilution ICPMS. • A microwave acid digestion using quartz vessel was suitable for Br analysis. • Sample dilution by NH 3 solution could remove memory effect for ICPMS measurement. • The analytical result of the ID-ICPMS showed consistency with that of INAA. • The ID-ICPMS developed could apply to certification of Br in candidate plastic CRM. - Abstract: The accurate analytical method of bromine (Br) in plastic was developed by an isotope dilution inductively coupled plasma mass spectrometry (ID-ICPMS). The figures of merit of microwave acid digestion procedures using polytetrafluoroethylene (PTFE) or quartz vessels were studied and the latter one was suitable for Br analysis since its material was free from Br contamination. The sample dilution procedures using Milli-Q water or ammonium (NH 3 ) solution were also studied to remove memory effect for ICPMS measurement. Although severe memory effect was observed on Milli-Q water dilution, NH 3 solution could remove it successfully. The accuracy of the ID-ICPMS was validated by a certified reference material (CRM) as well as the comparison with the analytical result obtained by an instrumental neutron activation analysis (INAA) as different analytical method. From these results, the ID-ICPMS developed in the present study could be evaluated as accurate analytical method of Br in plastic materials and it could apply to certification of Br in candidate plastic CRM with respect to such regulations related to RoHS (restriction of the use of hazardous substances in electrical and electronics equipment) directive

The Effects of Biochar on Germination and Growth of Wheat in Different Saline-alkali Soil

Institute of Scientific and Technical Information of China (English)

Guijun; WANG; Zhenwen; XU

2013-01-01

Saline alkali soil can cause physiological drought on crops,so only some salinity tolerant crops can grow in saline alkali soil.Biochar can increase the utilize efficiency of nutrient and the water retention of the soil,and affect the growth of the plant.In this research,four different proportion of biochar was added in five different levels of saline-alkali soil for pot culture experiment.The pH of the soil increases as the proportion of biochar increase in same saline-alkali level soil,while the EC decrease as the proportion of biochar increase.The germination rate of wheat seeds varies as the different of soil’s saline-alkali level.Notable among these results is the germination of wheat seeds in the serious saline-alkali soil without biochar added is 0,while in 45%biochar added in serious saline-alkali soil,the germination rate get to as high as 48.9%.Also,biochar improve the growth of wheat seedling,while for mild saline alkali soil and normal soil.Biochar had no obvious effect on the growth of wheat seedling.

Ligand exchange chromatography for analysis and preparative separation of tritium-labelled amino acids

International Nuclear Information System (INIS)

Zolotarev, Yu.A.; Zaitsev, D.A.; Penkina, V.I.; Dostavalov, I.N.; Myasoedov, N.F.

1988-01-01

Racemic tritium-labelled amino acids were separated into optical isomers by chromatography on a chiral polyacrylamide sorbent filled with copper ions. The polyacrylamide sorbent is synthesized by Mannich's reaction through the action of formaldehyde and L-phenylalanine upon polyacrylamide Biogel P-4 in an alkali phosphate buffer. Tritium-labelled amino acids are eluted by a weak alkali solution of ammonium carbonate. Data are presented on the ligand exchange chromatography of amino acids depending on the degree to which the sorbent is filled with copper ions and on the eluent concentration. Amino acids are isolated from the eluent on short columns filled with sulfonated cation exchanger in the H + form. HPLC on modified silica gel sorbents is also used for the analysis of tritium-labelled optically active amino acids. Amino acids are eluted by a weakly acidic water-methanol solution containing ammonium acetate. UV and scintillation flow type detectors are used. (author) 7 refs.; 8 figs

Alkali-Resistant Quasi-Solid-State Electrolyte for Stretchable Supercapacitors.

Science.gov (United States)

Tang, Qianqiu; Wang, Wenqiang; Wang, Gengchao

2016-10-05

Research on stretchable energy-storage devices has been motivated by elastic electronics, and considerable research efforts have been devoted to the development of stretchable electrodes. However, stretchable electrolytes, another critical component in stretchable devices, have earned quite little attention, especially the alkali-resistant ones. Here, we reported a novel stretchable alkali-resistant electrolyte made of a polyolefin elastomer porous membrane supported potassium hydroxide-potassium polyacrylate (POE@KOH-PAAK). The as-prepared electrolyte shows a negligible plastic deformation even after 1000 stretching cycles at a strain of 150% as well as a high conductivity of 0.14 S cm -1 . It also exhibits excellent alkali resistance, which shows no obvious degradation of the mechanical performance after immersion in 2 M KOH for up to 2 weeks. To demonstrate its good properties, a high-performance stretchable supercapacitor is assembled using a carbon-nanotube-film-supported NiCo 2 O 4 (CNT@NiCo 2 O 4 ) as the cathode and Fe 2 O 3 (CNT@Fe 2 O 3 ) as the anode, proving great application promise of the stretchable alkali-resistant electrolyte in stretchable energy-storage devices.

Mechanical Behaviour of Soil Improved by Alkali Activated Binders

Directory of Open Access Journals (Sweden)

Enza Vitale

2017-11-01

Full Text Available The use of alkali activated binders to improve engineering properties of clayey soils is a novel solution, and an alternative to the widely diffused improvement based on the use of traditional binders such as lime and cement. In the paper the alkaline activation of two fly ashes, by-products of coal combustion thermoelectric power plants, has been presented. These alkali activated binders have been mixed with a clayey soil for evaluating the improvement of its mechanical behaviour. One-dimensional compression tests on raw and treated samples have been performed with reference to the effects induced by type of binder, binder contents and curing time. The experimental evidences at volume scale of the treated samples have been directly linked to the chemo-physical evolution of the binders, investigated over curing time by means of X Ray Diffraction. Test results showed a high reactivity of the alkali activated binders promoting the formation of new mineralogical phases responsible for the mechanical improvement of treated soil. The efficiency of alkali activated binders soil treatment has been highlighted by comparison with mechanical performance induced by Portland cement.

Alkali-explosion pretreatment of straw and bagasse for enzymic hydrolysis.

Science.gov (United States)

Puri, V P; Pearce, G R

1986-04-01

Sugarcane bagasse and wheat straw were subjected to alkali treatment at 200 degrees C for 5 min and at 3.45 MPa gas pressure (steam and nitrogen), followed by an explosive discharge through a defibrating nozzle, in an attempt to improve the rate and extent of digestibility. The treatment resulted in the solubilization of 40-45% of the components and in the production of a pulp that gave saccharification yields of 80 and 65% in 8 h for bagasse and wheat straw, respectively. By comparison, alkali steaming at 200 degrees C (1.72 MPa) for 5 min gave saccharification yields of only 58 and 52% in 48 h. The increase in temperature from 140 to 200 degrees C resulted in a gradual increase in in vitro organic matter digestibility (IVOMD) for both the substrates. Also, the extent of alkalinity during pretreatment appears to effect the reactivity of the final product towards enzymes. Pretreatment times ranging from 5 to 60 caused a progressive decline in the IVOMD of bagasse and wheat straw by the alkali explosion method and this was accompanied by a progressive decrease in pH values after explosion. In the alkali-steaming method, pretreatment time had no apparent effect with either substrate. An analysis of the alkali-exploded products showed that substantial amounts of hemicellulose and a small proportion of the lignin were solubilized. The percentage crystallinity of the cellulose did not alter in either substrate but there was a substantial reduction in the degree of polymerization. The superiority of the alkali-explosion pretreatment is attributed to the efficacy of fiber separation and disintegration; this increases the surface area and reduces the degree of polymerization.

Using Modified Remote Sensing Imagery to Interpret Changes in Cultivated Land under Saline-Alkali Conditions

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Hui Gao

2016-07-01

Full Text Available Managing the rapidly changing saline-alkali land under cultivation in the coastal areas of China is important not only for mitigating the negative impacts of such land on the environment, but also for ensuring long-term sustainability of agriculture. In this light, setting up rapid monitoring systems to assist decision-making in developing sustainable management plans is therefore an absolute necessity. In this study, we developed a new interpretation system where symbols are used to grade and classify saline-alkali lands in space and time, based on the characteristics of plant cover and features of remote sensing images. The system was used in combination with the maximum likelihood supervised classification to analyze the changes in cultivated lands under saline-alkali conditions in Huanghua City. The analysis revealed changes in the area and spatial distribution of cultivated under saline-alkali conditions in the region. The total area of saline-alkali land was 139,588.8 ha in 1992 and 134,477.5 ha in 2011. Compared with 1992, severely and moderately saline-alkali land areas decreased in 2011. However, non/slightly saline land areas increased over that in 1992. The results showed that the salinization rate of arable lands in Huanghua City decreased from 1992 to 2011. The moderately saline-alkali land southeast of the city transformed into non/slightly saline-alkaline. Then, severely saline-alkali land far from the coastal zone west of the city became moderately saline-alkaline. Spatial changes in cultivated saline-alkali lands in Huanghua City were such that the centers of gravity (CG of severely and non/slightly saline-alkali land moved closer the coastline, while that of the moderately saline-alkali land moved from southwest coastal line to northwest. Factors influencing changes in cultivated lands in the saline-alkali ecosystem included climate, hydrology and human activity. Thus, studies are required to further explore these factors in

Synthesis and binding properties of calix[4]arene diamide dicarboxylic acids

International Nuclear Information System (INIS)

Arnaud-Neu, F.; Barboso, S.; Schwing-Weill, M.J.; Casnati, A.; Pinalli, A.; Ungaro, R.

2000-01-01

Calix[4]arenes diametrically substituted at the lower rim with two carboxylic acid and two tertiary amide binding groups were obtained in good yields and their acid-base properties studied in methanol solution. Complexation studies, performed in methanol by potentiometry, show that mononuclear (MLH z , z = 0,1) or dinuclear (M 2 L) complexes are formed with alkali metal cations, whereas M x L 2 H z (x=1,2,z = 0,1) species, involving two ligands, are also present with alkaline-earth cations. Both ligands show a remarkable selectivity for Ca 2+ and Sr 2+ among alkali and alkaline-earth metal ions. (authors)

Third phase formation in organic solutions in the extraction of mono-acids by tertiary trialcoyl-amines diluted in very slightly polar organic solvents

International Nuclear Information System (INIS)

Robaglia, Michele

1973-01-01

The phenomena of third phase formation which can occur during the extraction of an acid with a tertiary amine diluted in a low polarity diluent are studied. In the first part a system including water (TnOA - C 6 H 12 - HCl - H 2 O) is compared with an anhydrous system (TnOA - C 6 H 12 - HCl - N 2 ). There are two kinds of gaps. One during amine salification, another one during the extraction of excess acid. The important part of the water content of the organic phase is demonstrated. The presence of water enhances the gaps. The polar water molecules are dissolved inside the tri-octylamine salt micelles. The heavy phase is formed by aggregates, the light phase represents the solubility of the non soluble species in the medium. In the second part are studied the influence of some parameters (like nature of diluent, acid, amine and temperature) on the gaps formation and on the extraction of excess acid and water. In every cases the part played by water remains the same. Finally some comparisons are made between tertiary systems and binary systems which formed them. The binary systems were studied by the mean of crystallization curves. (author) [fr

Influence of alkali metal hydroxides on corrosion of Zr-based alloys

International Nuclear Information System (INIS)

Jeong, Y.H.; Ruhmann, H.; Garzarolli, F.

1997-01-01

In this study the influence of group-1 alkali hydroxides on different zirconium based alloys has been evaluated. The experiments have been carried out in small stainless steel autoclaves at 350 deg. C in pressurized 17 MPa water, with in low (0.32 mmol), medium (4.3 mmol) and high (31.5 mmol) equimolar concentrations of Li-, Na-, K-, Rb- and Cs-Hydroxides. Two types of alloys have been investigated: Zr-Sn-(Transition metal) and Zr-Sn-Nb-(Transition metal). The corrosion behaviour was evaluated from weight gain measurements. From the experiments the cation could be identified as the responsible species for zirconium alloy corrosion in alkalized water. The radius of the cation governs the corrosion behaviour in the pre accelerated region of zircaloy corrosion. Incorporating of alkali cations into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significantly lower effect for the other bases. Nb containing alloys show lower corrosion resistance than alloys from the Zr-Sn-TRM system in all alkali solutions. Both types of alloys corrode significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behaviour in the different alkali environments and taking into account the tendency to promote accelerate corrosion, CsOH and KOH are possible alternate alkalis for PWR application. (author). 17 refs, 15 figs, 5 tabs

Influence of alkali metal hydroxides on corrosion of Zr-based alloys

Energy Technology Data Exchange (ETDEWEB)

Jeong, Y H [Korea Atomic Energy Research Inst., Dae Jun (Korea, Republic of); Ruhmann, H; Garzarolli, F [Siemens-KWU, Power Generation Group, Erlangen (Germany)

1997-02-01

In this study the influence of group-1 alkali hydroxides on different zirconium based alloys has been evaluated. The experiments have been carried out in small stainless steel autoclaves at 350 deg. C in pressurized 17 MPa water, with in low (0.32 mmol), medium (4.3 mmol) and high (31.5 mmol) equimolar concentrations of Li-, Na-, K-, Rb- and Cs-Hydroxides. Two types of alloys have been investigated: Zr-Sn-(Transition metal) and Zr-Sn-Nb-(Transition metal). The corrosion behaviour was evaluated from weight gain measurements. From the experiments the cation could be identified as the responsible species for zirconium alloy corrosion in alkalized water. The radius of the cation governs the corrosion behaviour in the pre accelerated region of zircaloy corrosion. Incorporating of alkali cations into the zirconium oxide lattice is probably the mechanism which allows the corrosion enhancement for Li and Na and the significantly lower effect for the other bases. Nb containing alloys show lower corrosion resistance than alloys from the Zr-Sn-TRM system in all alkali solutions. Both types of alloys corrode significantly more in LiOH and NaOH than in the other alkali environments. Lowest corrosive aggressiveness has been found for CsOH followed by KOH. Concluding from the corrosion behaviour in the different alkali environments and taking into account the tendency to promote accelerate corrosion, CsOH and KOH are possible alternate alkalis for PWR application. (author). 17 refs, 15 figs, 5 tabs.

Mechanism of the alkali degradation of (6-4) photoproduct-containing DNA.

Science.gov (United States)

Arichi, Norihito; Inase, Aki; Eto, Sachise; Mizukoshi, Toshimi; Yamamoto, Junpei; Iwai, Shigenori

2012-03-21

The (6-4) photoproduct is one of the major damaged bases produced by ultraviolet light in DNA. This lesion is known to be alkali-labile, and strand breaks occur at its sites when UV-irradiated DNA is treated with hot alkali. We have analyzed the product obtained by the alkali treatment of a dinucleoside monophosphate containing the (6-4) photoproduct, by HPLC, NMR spectroscopy, and mass spectrometry. We previously found that the N3-C4 bond of the 5' component was hydrolyzed by a mild alkali treatment, and the present study revealed that the following reaction was the hydrolysis of the glycosidic bond at the 3' component. The sugar moiety of this component was lost, even when a 3'-flanking nucleotide was not present. Glycosidic bond hydrolysis was also observed for a dimer and a trimer containing 5-methyl-2-pyrimidinone, which was used as an analog of the 3' component of the (6-4) photoproduct, and its mechanism was elucidated. Finally, the alkali treatment of a tetramer, d(GT(6-4)TC), yielded 2'-deoxycytidine 5'-monophosphate, while 2'-deoxyguanosine 3'-monophosphate was not detected. This result demonstrated the hydrolysis of the glycosidic bond at the 3' component of the (6-4) photoproduct and the subsequent strand break by β-elimination. It was also shown that the glycosidic bond at the 3' component of the Dewar valence isomer was more alkali-labile than that of the (6-4) photoproduct.

Urine alkalization facilitates uric acid excretion

Science.gov (United States)

2010-01-01

Background Increase in the incidence of hyperuricemia associated with gout as well as hypertension, renal diseases and cardiovascular diseases has been a public health concern. We examined the possibility of facilitated excretion of uric acid by change in urine pH by managing food materials. Methods Within the framework of the Japanese government's health promotion program, we made recipes which consist of protein-rich and less vegetable-fruit food materials for H+-load (acid diet) and others composed of less protein but vegetable-fruit rich food materials (alkali diet). Healthy female students were enrolled in this consecutive 5-day study for each test. From whole-day collected urine, total volume, pH, organic acid, creatinine, uric acid and all cations (Na+,K+,Ca2+,Mg2+,NH4+) and anions (Cl-,SO42-,PO4-) necessary for the estimation of acid-base balance were measured. Results Urine pH reached a steady state 3 days after switching from ordinary daily diets to specified regimens. The amount of acid generated ([SO42-] +organic acid-gut alkai) were linearly related with those of the excretion of acid (titratable acidity+ [NH4+] - [HCO3-]), indicating that H+ in urine is generated by the metabolic degradation of food materials. Uric acid and excreted urine pH retained a linear relationship, where uric acid excretion increased from 302 mg/day at pH 5.9 to 413 mg/day at pH 6.5, despite the fact that the alkali diet contained a smaller purine load than the acid diet. Conclusion We conclude that alkalization of urine by eating nutritionally well-designed food is effective for removing uric acid from the body. PMID:20955624

Growing Chlorella vulgaris in Photobioreactor by Continuous Process Using Concentrated Desalination: Effect of Dilution Rate on Biochemical Composition

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Ângelo Paggi Matos

2014-01-01

Full Text Available Desalination wastewater, which contains large amount of salt waste, might lead to severely environmental pollution. This study evaluated the effect of dilution rate (0.1≤D≤0.3 day−1 on microalgal biomass productivity, lipid content, and fatty acid profile under steady-state condition of Chlorella vulgaris supplemented with concentrated desalination. Continuous culture was conducted for 55 days. Results show that the biomass productivity (Px varied from 57 to 126 mg L−1 d−1 (dry mass when the dilution rate ranged from 0.1 to 0.3 day−1. At lowest dilution rate (D=0.1 day−1, the continuous culture regime ensured the highest values of maximum biomass concentration (Xm=570±20 mL−1 and protein content (52%. Biomass lipid content was an increasing function of D. The most abundant fatty acids were the palmitic (25.3±0.6% at D=0.1 day−1 and the gamma-linolenic acid (23.5±0.1% at D=0.3 day−1 ones. These fatty acids present 14 to 18 carbons in the carbon chain, being mainly saturated and polyunsaturated, respectively. Overall, the results show that continuous culture is a powerful tool to investigate the cell growth kinetics and physiological behaviors of the algae growing on desalination wastewater.

Behaviour of gaseous alkali compounds from coal gasification

International Nuclear Information System (INIS)

Nykaenen, J.

1996-01-01

In this project the behaviour of alkali compounds has been studied with a chemical equilibrium model. The goal is to evaluate the possibilities to remove the sodium and potassium compounds together with the fly ash particles by using a ceramic honeycomb filter. The studied processes include both CO 2 /O 2 - and air-blown gasification and combustion. The results show that the difference between the processes with flue gas recirculation and air-blown processes is small. This is due to that the equilibrium concentration of the dominant gaseous alkali compound, chloride, is more or less the same in both processes. This research project is closely connected to the EU-project coordinated by the Delft University of Technology (DUT). In that project alkali concentration of the fuel gas from a 1.6 MW pilot plant will be measured. During the next phase of this research the results from DUT will be compared with the results of this presentation. (author)

Alkali and heavy metal emissions of the PCFB-process; Alkali- ja raskasmetallipaeaestoet PCFB-prosessista

Energy Technology Data Exchange (ETDEWEB)

Kuivalainen, R; Eriksson, T; Lehtonen, P [Foster Wheeler Energia Oy, Karhula (Finland)

1997-10-01

Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed in Karhula R and D Center since 1986. As part of the development, 10 MW PCFB test facility was built in 1989. The test facility has been used for performance testing with different coal types through the years 1990-1995 in order to gain data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The main object of the project was to measure vapor phase Na and K concentrations in the PCFB flue gas after hot gas filter and investigate the effects of process conditions and sorbents on alkali release. The measurements were performed using plasma assisted method of TUT Laboratory of Plasma Technology and wet absorption method of VTT Energy. The measurements were carried out during three test campaigns at PCFB Test Facility in Karhula. In autumn 1995 both VTT and TUT methods were used. The measurements of the following test period in spring 1996 were performed by VTT, and during the last test segment in autumn 1996 TUT method was in use. During the last test period, the TUT instrument was used as semi-continuous (3 values/minute) alkali analyzer for part of the time. The measured Na concentrations were below 30 ppb(w) in all measured data points. The results of K were below 10 ppb(w). The accuracies of the both methods are about +50 % at this concentration range. The scatter of the data covers the effects of different process variables on the alkali emission. The measured emissions are at the same order of magnitude as the guideline emission limits estimated by gas turbine manufacturers

Influence of curing conditions on durability of alkali-resistant glass ...

Indian Academy of Sciences (India)

Glass fibres in concrete material often increase the flexural strength. However, these fibres when in contact with cement are altered by alkali reactions due to the presence of portlandite. This study presents the results of investigation to show the effect of curing conditions on the durability of alkali-resistant glass fibres in ...

Alkali replacement raises urinary citrate excretion in patients with topiramate-induced hypocitraturia.

Science.gov (United States)

Jhagroo, R Allan; Wertheim, Margaret L; Penniston, Kristina L

2016-01-01

The aims of this study were to assess (1) the magnitude and temporality of decreased urinary citrate excretion in patients just starting topiramate and (2) the effect of alkali replacement on topiramate-induced hypocitraturia. Study 1 was a prospective, non-intervention study in which patients starting topiramate for headache remediation provided pre- and post-topiramate 24 h urine collections for measurement of urine citrate. Study 2 was a clinical comparative effectiveness study in which patients reporting to our stone clinic for kidney stones and who were treated with topiramate were prescribed alkali therapy. Pre- and post-alkali 24 h urinary citrate excretion was compared. Data for 12 and 22 patients (studies 1 and 2 respectively) were evaluated. After starting topiramate, urinary citrate excretion dropped significantly by 30 days (P = 0.016) and 62% of patients had hypocitraturia (citrate alkali, urine citrate increased in stone-forming patients on topiramate (198 ± 120 to 408 ± 274 mg day(-1) ; P = 0.042 for difference). 85% of patients were hypocitraturic on topiramate alone vs. 40% after adding alkali. The increase in urinary citrate was greater in patients provided ≥ 90 mEq potassium citrate. Our study is the first to provide clinical evidence that alkali therapy can raise urinary citrate excretion in patients who form kidney stones while being treated with topiramate. Clinicians should consider alkali therapy for reducing the kidney stone risk of patients benefitting from topiramate treatment for migraine headaches or other conditions. © 2015 The British Pharmacological Society.

Anion exchange membrane based on alkali doped poly(2,5-benzimidazole) for fuel cell

CSIR Research Space (South Africa)

Luo, H

2012-02-01

Full Text Available The properties of alkali doped poly(2,5-benzimidazole) membrane with different alkali doping level for fuel cell application is reported in this work. The alkali doping level played an important role for the ion conductivity of the membrane. The ion...

Overall process considerations for using dilute acid cellulose hydrolysis technology to produce ethanol from biomass

International Nuclear Information System (INIS)

Elander, R.; Ibsen, K.; Hayward, T.; Nagle, N.; Torget, R.

1997-01-01

Recent advances in reactors, designed for the dilute acid thermochemical treatment of biomass, have resulted in the development of process alternatives in which both cellulose and hemicellulose are hydrolyzed to soluble sugars in high yields. The optimal extent of cellulose hydrolysis will depend on both the performance and economics of the thermochemical treatment operation, and on subsequent unit operations in the bioethanol production process. Examples of subsequent unit operation interactions include the extent to which cellulase enzymes are used to hydrolyze any remaining cellulose, kinetics and conditions of a largely soluble mixed sugar cofermentation, and the extent to which removal of compounds that inhabit fermenting microorganisms is required. In addition, a number of process operation and economic considerations affect the ultimate economic viability of this type of biomass hydrolysis process. These considerations include reactor design issues to accommodate the kinetic parameters of the various hydrolysis and sugar degradation reactions, liquid volume requirements to achieve acceptable sugar yields, sugar concentrations that result from such a process and their impact on subsequent fermentation volumes and ethanol recovery operations, potential co-product opportunities that result from solubilized lignin, and process steam requirements. Several potential whole-process configurations are presented and key process and economic issues for each are discussed. (author)

Powder X-ray diffraction study af alkali alanates

DEFF Research Database (Denmark)

Cao, Thao; Mosegaard Arnbjerg, Lene; Jensen, Torben René

Powder X-ray diffraction study of alkali alanates Thao Cao, Lene Arnbjerg, Torben R. Jensen. Center for Materials Crystallography (CMC), Center for Energy Materials (CEM), iNANO and Department of Chemistry, Aarhus University, DK-8000, Denmark. Abstract: To meet the energy demand in the future...... for mobile applications, new materials with high gravimetric and volumetric storage capacity of hydrogen have to be developed. Alkali alanates are promising for hydrogen storage materials. Sodium alanate stores hydrogen reversibly at moderate conditions when catalysed with, e.g. titanium, whereas potassium...

Study of corrosion susceptibility of stainless steel-304 and stainless steel-316 under mechanical stress in diluted boiling nitric acid with chlorides

International Nuclear Information System (INIS)

Desjardins, D.; Puiggali, M.; El Kheloui, A.; Petit, M.C.; Clement, C.; Berge, J.P.

1991-01-01

A detailed study of corrosion of stressed 304 and 316 stainless steels in boiling solutions of diluted nitric acid in presence of chloride is presented. After a chemical study of the electrolyte, the different kinds of corrosion observed are represented on HNO 3 concentration - Cl - concentration diagrams. A more fundamental study based on several electrochemical techniques (forward scan and return potentiodynamic curves, potentiokinetic curves with different scan rates, sample depassivation by rapid straining under potentiostatic control) is carried out. The results allow to confirm the observations and to explain them in terms of competition between anodic dissolution, depassivation, repassivation processes with a precise analyze of the role of the solution and of the mechanical stress [fr

Optimization of dilute sulfuric acid pretreatment to maximize combined sugar yield from sugarcane bagasse for ethanol production.

Science.gov (United States)

Benjamin, Y; Cheng, H; Görgens, J F

2014-01-01

Increasing fermentable sugar yields per gram of biomass depends strongly on optimal selection of varieties and optimization of pretreatment conditions. In this study, dilute acid pretreatment of bagasse from six varieties of sugarcane was investigated in connection with enzymatic hydrolysis for maximum combined sugar yield (CSY). The CSY from the varieties were also compared with the results from industrial bagasse. The results revealed considerable differences in CSY between the varieties. Up to 22.7 % differences in CSY at the optimal conditions was observed. The combined sugar yield difference between the best performing variety and the industrial bagasse was 34.1 %. High ratio of carbohydrates to lignin and low ash content favored the release of sugar from the substrates. At mild pretreatment conditions, the differences in bioconversion efficiency between varieties were greater than at severe condition. This observation suggests that under less severe conditions the glucose recovery was largely determined by chemical composition of biomass. The results from this study support the possibility of increasing sugar yields or improving the conversion efficiency when pretreatment optimization is performed on varieties with improved properties.

Assesment of Alkali Resistance of Basalt Used as Concrete Aggregates

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al-Swaidani Aref M.

2015-11-01

Full Text Available The objective of this paper is to report a part of an ongoing research on the influence of using crushed basalt as aggregates on one of durability-related properties of concrete (i.e. alkali-silica reaction which is the most common form of Alkali-Aggregate Reaction. Alkali resistance has been assessed through several methods specified in the American Standards. Results of petrographic examination, chemical test (ASTM C289 and accelerated mortar bar test (ASTM C1260 have particularly been reported. In addition, the weight change and compressive strength of 28 days cured concrete containing basaltic aggregates were also reported after 90 days of exposure to 10% NaOH solution. Dolomite aggregate were used in the latter test for comparison. The experimental results revealed that basaltic rocks quarried from As-Swaida’a region were suitable for production of aggregates for concrete. According to the test results, the studied basalt aggregates can be classified as innocuous with regard to alkali-silica reaction. Further, the 10% sodium hydroxide attack did not affect the compressive strength of concrete.

Charge-charge liquid structure factor and the freezing of alkali halides

International Nuclear Information System (INIS)

March, N.H.; Tosi, M.P.

1980-10-01

The peak height of the charge-charge liquid structure factor Ssub(QQ) in molten alkali halides is proposed as a criterion for freezing. Available data on molten alkali chlorides, when extrapolated to the freezing point suggests Ssub(QQ)sup(max) approximately 5. (author)

Investigation on lithium migration for treating alkali-silica reaction affected concrete

NARCIS (Netherlands)

Silva De Souza, L.M.; Polder, R.B.; Copuroglu, O.

2014-01-01

Alkali-silica reaction (ASR) is one of the major deterioration mechanisms that affect numerous concrete structures worldwide. During the reaction, hydroxyl and alkali (sodium and potassium ) ions react with certain siliceous compounds in the aggregate, forming a hygroscopic gel. The gel absorbs

Gradient heating protocol for a diode-pumped alkali laser

Science.gov (United States)

Cai, He; Wang, You; Han, Juhong; Yu, Hang; Rong, Kepeng; Wang, Shunyan; An, Guofei; Wang, Hongyuan; Zhang, Wei; Wu, Peng; Yu, Qiang

2018-06-01

A diode-pumped alkali laser (DPAL) has gained rapid development in the recent years. Until now, the structure with single heater has been widely utilized to adjust the temperature of an alkali vapor cell in most of the literatures about DPALs. However, for an end-pumped DPAL using single heater, most pump energy is absorbed by the gain media near the entrance cell window because of the large absorption cross section of atomic alkali. As a result, the temperature in the pumping area around the entrance window will go up rapidly, especially in a case of high pumping density. The temperature rise would bring about some negative influences such as thermal effects and variations in population density. In addition, light scattering and window contamination aroused by the chemical reaction between the alkali vapor and the buffer gas will also affect the output performance of a DPAL system. To find a solution to these problems, we propose a gradient heating approach in which several heaters are tandem-set along the optical axis to anneal an alkali vapor cell. The temperature at the entrance window is adjusted to be lower than that of the other side. By using this novel scheme, one can not only achieve a homogeneous absorption of the pump energy along the cell axis, but also decrease the possibility of the window damage in a DPAL configuration. The theoretical simulation of the laser output features has been carried out for a configuration of multiple heaters. Additionally, the DPAL output performance under different gradient temperatures is also discussed in this paper. The conclusions might be helpful for development of a high-powered and high-beam-quality DPAL.

Alkali and heavy metals emissions of the PCFB-process

International Nuclear Information System (INIS)

Kuivalainen, R.; Eriksson, T.; Koskinen, J.; Lehtonen, P.

1995-01-01

Pressurized Circulating Fluidized Bed (PCFB) combustion technology has been developed by A. Ahlstrom Corporation since 1986. As a part of the development, a 10 MV PCFB Test Facility was constructed at Hans Ahlstrom Laboratory in Karhula, Finland in 1989. The Test Facility has been used for performance testing with different coal types through the years 1990-1994 for obtaining data for design and commercialization of the high-efficiency low-emission PCFB combustion technology. The project Y44 'Alkali and heavy metal emissions of the PCFB-process' is part of national LIEKKI 2 research program and it continues the work started under alkali measurement project Y33 in 1994. The objective of the project is to measure vapor phase alkali and heavy metal concentrations in the PCFB flue gas after high-temperature high-pressure particulate filter and to investigate the effects of process conditions and sorbents on alkali release. The measured Na concentrations were between 0,03 and 0,21 ppm(w). The results of K were between 0,01 and 0,08 ppm(w). The accuracy of the results is about +-50 percent at this concentration range. The scatter of the data covers the effects of different process variables on the alkali emission. The measured emissions at 800-850 deg C are at the same order of magnitude as the guideline emission limits given by gas turbine manufacturers for flue gas at 1000-1200 deg C. The measurements and development of the analyses methods are planned to be continued during PCFB test runs in autumn 1995 in cooperation with laboratories of VTT Energy and Tampere University of Technology. (author)

The direct observation of alkali vapor species in biomass combustion and gasification

Energy Technology Data Exchange (ETDEWEB)

French, R J; Dayton, D C; Milne, T A

1994-01-01

This report summarizes new data from screening various feedstocks for alkali vapor release under combustion conditions. The successful development of a laboratory flow reactor and molecular beam, mass spectrometer interface is detailed. Its application to several herbaceous and woody feedstocks, as well as a fast-pyrolysis oil, under 800 and 1,100{degrees}C batch combustion, is documented. Chlorine seems to play a large role in the facile mobilization of potassium. Included in the report is a discussion of relevant literature on the alkali problem in combustors and turbines. Highlighted are the phenomena identified in studies on coal and methods that have been applied to alkali speciation. The nature of binding of alkali in coal versus biomass is discussed, together with the implications for the ease of release. Herbaceous species and many agricultural residues appear to pose significant problems in release of alkali species to the vapor at typical combustor temperatures. These problems could be especially acute in direct combustion fired turbines, but may be ameliorated in integrated gasification combined cycles.

Metal analyses of ash derived alkalis from banana and plantain ...

African Journals Online (AJOL)

The objective of this work was to determine the metal content of plantain and banana peels ash derived alkali and the possibility of using it as alternate and cheap source of alkali in soap industry. This was done by ashing the peels and dissolving it in de-ionised water to achieve the corresponding hydroxides with pH above ...

Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

Energy Technology Data Exchange (ETDEWEB)

Lee, S.H.D.; Teats, F.G.; Swift, W.M. (Argonne National Lab., IL (United States)); Banerjee, D.D. (Illinois Clean Coal Inst., Carterville, IL (United States))

1993-01-01

Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950[degree]C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

Energy Technology Data Exchange (ETDEWEB)

Lee, S.H.D.; Teats, F.G.; Swift, W.M. [Argonne National Lab., IL (United States); Banerjee, D.D. [Illinois Clean Coal Inst., Carterville, IL (United States)

1993-04-01

Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950{degree}C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.

Effect of alkali and heat treatments for bioactivity of TiO{sub 2} nanotubes

Energy Technology Data Exchange (ETDEWEB)

Kim, Seo young, E-mail: mast6269@nate.com [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Kim, Yu kyoung, E-mail: yk0830@naver.com [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Park, Il song, E-mail: ilsong@jbnu.ac.kr [Division of Advanced Materials Engineering, Research Center for Advanced Materials Development and Institute of Biodegradable Materials, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Jin, Guang chun, E-mail: jingc88@126.com [Oral Medical College, Beihua University, Jilin City 132013 (China); Bae, Tae sung, E-mail: bts@jbnu.ac.kr [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of); Lee, Min ho, E-mail: mh@jbnu.ac.kr [Dept. of Dental Biomaterials and Institute of Bio degradable material, Institute of Oral Bioscience and BK21 plus project, School of Dentistry, Chonbuk National University, Jeonju, 561-756 (Korea, Republic of)

2014-12-01

Highlights: • TiO{sub 2} nanotubes formed via anodization were treated by alkali and heat. • The surface roughness was increased after alkali treatment (p < 0.05). • After alkali and heat treatment, the wettability was better than before treatment. • Alkali treated TiO{sub 2} nanotubes were shown higher HAp formation in SBF. • Heat treatment affected on the attachment of cells for alkali treated nanotubes. - Abstract: In this study, for improving the bioactivity of titanium used as an implant material, alkali and heat treatments were carried out after formation of the nanotubes via anodization. Nanotubes with uniform length, diameter, and thickness were formed by anodization. The alkali and heat-treated TiO{sub 2} nanotubes were covered with the complex network structure, and the Na compound was generated on the surface of the specimens. In addition, after 5 and 10 days of immersion in the SBF, the crystallized OCP and HAp phase was significantly increased on the surface of the alkali-treated TiO{sub 2} nanotubes (PNA) and alkali and heat-treated TiO{sub 2} nanotubes (PNAH) groups. Cell proliferation was decreased due to the formation of amorphous sodium titanate (Na{sub 2}TiO{sub 3}) layer on the surface of the PNA group. However, anatase and crystalline sodium titanate were formed on the surface of the PNAH group after heat treatment at 550 °C, and cell proliferation was improved. Thus, PNA group had higher HAp forming ability in the simulated body fluid. Additional heat treatment affected on enhancement of the bioactivity and the attachment of osteoblasts for PNA group.

Mechanisms and kinetics of electrodeposition of alkali metals on solid and liquid mercury electrodes