oalib
Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
ON THE CONCENTRATION OF CADMIUM AND RECOVERY OF LEAD FROM THE LEAD BLAST FURNACE DUST

CHAO PEI-YING,LEE KENG-SHENG,FANG BING,TAN KWO YONG,WANG CHUEN-CHI Institute of Metal Research,Academia Sinica Smelting Works No l,Ministry of Metal Industries,

金属学报 , 1957,
Abstract: On the basis of the distribution of lead, cadmium, arsenic and zinc amongthe various phases during the smelting process, the disadvantages of the currentlyadopted method using silica as slag-forming material for the treatment of leadblast furnace dust have been discussed. Experiments have been carried out in treating the dust with a new method,which is based upon the iron precipitation reaction with Na_2CO_3 as flux. Resultsobtained show: 1) 99.55% cadmium of the original dust may be concentrated intothe secondary dust; 2) 95.6% of lead may be recovered simultaneously, its purityis about 97%; 3) as cadmium in the secondary dust is easily leachable, a rate ofrecovery of cadmium as high as 98.5% could be obtained. It is suggested that,the present method, in view of its high recovery of valuable metals and its com-paratively simple operating procedure, is well suitable for the dust treatment inthe lead smelting industries.
Distribution of Bio-accumulated Cd and Cr in two Vigna species and the Associated Histological Variations  [PDF]
Ratheesh Chandra, P.,Abdussalam A.K.,Nabeesa Salim,Jos T. Puthur
Journal of Stress Physiology & Biochemistry , 2010,
Abstract: In nutrient culture experiments, bioaccumulation and anatomical effects of cadmium (CdCl2 - 20μM) and chromium (K2Cr2O7 - 600 μM) on the structure of root and stem was studied by histochemical and analytical methods in Vigna radiata and Vigna unguiculata. Each metal exerted specific influences on the anatomy of various tissues in root and stem. Histochemical localisation of cadmium and chromium was observed in the stained sections of root and stem. Atomic Absorption Spectrophotometric study revealed maximum accumulation of cadmium and chromium in the root tissue as compared to shoot with significant variation among the species. Abundant occurrences of densely stained deposits of chromium were seen in the root stelar region of V. unguiculata and to a lesser extend in V. radiata. Cadmium accumulation in V. radiata was comparatively more than that of V. unguiculata. The findings also revealed that the accumulation pattern of cadmium and chromium varies between species and hence is species specific.
Activation of Methanogenesis by Cadmium in the Marine Archaeon Methanosarcina acetivorans  [PDF]
Elizabeth Lira-Silva, M. Geovanni Santiago-Martínez, Viridiana Hernández-Juárez, Rodolfo García-Contreras, Rafael Moreno-Sánchez, Ricardo Jasso-Chávez
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0048779
Abstract: Methanosarcina acetivorans was cultured in the presence of CdCl2 to determine the metal effect on cell growth and biogas production. With methanol as substrate, cell growth and methane synthesis were not altered by cadmium, whereas with acetate, cadmium slightly increased both, growth and methane rate synthesis. In cultures metabolically active, incubations for short-term (minutes) with 10 μM total cadmium increased the methanogenesis rate by 6 and 9 folds in methanol- and acetate-grown cells, respectively. Cobalt and zinc but not copper or iron also activated the methane production rate. Methanogenic carbonic anhydrase and acetate kinase were directly activated by cadmium. Indeed, cells cultured in 100 μM total cadmium removed 41–69% of the heavy metal from the culture and accumulated 231–539 nmol Cd/mg cell protein. This is the first report showing that (i) Cd2+ has an activating effect on methanogenesis, a biotechnological relevant process in the bio-fuels field; and (ii) a methanogenic archaea is able to remove a heavy metal from aquatic environments.
Recovery of Copper from Copper and Cadmium Sediment
从铜镉渣中回收铜

ZENG Mao-hua,XI Chang-sheng,PENG Cui-hong,LONG Lai-shou,
曾懋华
,奚长生,彭翠红,龙来寿

过程工程学报 , 2004,
Abstract: The displacement of copper from copper and cadmium sediment by different metallic reducing agents was studied. The result of experiment showed that the displacement of copper by zinc was not the optimum technique, and the displacement of copper by fresh sponge cadmium was better. A new method of displacement of copper using fresh sponge cadmium was presented. The new method has some advantages which reduced the displacement of coexistence ion and prevented the release of poisonous gas effectively. Some important facts which affect reaction were researched, for example, the quantity of metallic reducing agent, the time of reaction and the temperature of reaction etc. The sponge copper was obtained from acid solution of copper and cadmium sediment which contained 2% copper by fresh sponge cadmium and the purity of sponge copper was 95%, the recovery of copper was over 99%.
Bio-Sensing of Cadmium(II) Ions Using Staphylococcus aureus  [PDF]
Jiri Sochor,Ondrej Zitka,David Hynek,Eva Jilkova,Ludmila Krejcova,Libuse Trnkova,Vojtech Adam,Jaromir Hubalek,Jindrich Kynicky,Radimir Vrba,Rene Kizek
Sensors , 2011, DOI: 10.3390/s111110638
Abstract: Cadmium, as a hazardous pollutant commonly present in the living environment, represents an important risk to human health due to its undesirable effects (oxidative stress, changes in activities of many enzymes, interactions with biomolecules including DNA and RNA) and consequent potential risk, making its detection very important. New and unique technological and biotechnological approaches for solving this problems are intensely sought. In this study, we used the commonly occurring potential pathogenic microorganism Staphylococcus aureus for the determination of markers which could be used for sensing of cadmium(II) ions. We were focused on monitoring the effects of different cadmium(II) ion concentrations (0, 1.25, 2.5, 5, 10, 15, 25 and 50 μg mL?1) on the growth and energetic metabolism of Staphylococcus aureus. Highly significant changes have been detected in the metabolism of thiol compounds—specifically the protein metallothionein (0.79–26.82 mmol/mg of protein), the enzyme glutathione S-transferase (190–5,827 μmol/min/mg of protein), and sulfhydryl groups (9.6–274.3 μmol cysteine/mg of protein). The ratio of reduced and oxidized glutathione indicated marked oxidative stress. In addition, dramatic changes in urease activity, which is connected with resistance of bacteria, were determined. Further, the effects of cadmium(II) ions on the metabolic pathways of arginine, β-glucosidase, phosphatase, N-acetyl β-D-glucosamine, sucrose, trehalose, mannitol, maltose, lactose, fructose and total proteins were demonstrated. A metabolomic profile of Staphylococcus aureus under cadmium(II) ion treatment conditions was completed seeking data about the possibility of cadmium(II) ion accumulation in cells. The results demonstrate potential in the application of microorganisms as modern biosensor systems based on biological components.
RECOVERY OF CADMIUM AND NICKEL FROM SCRAP Ni-Cd BATTERIES
JXZhu,BYu,JHLi,
J.X. Zhu
,B. Yu,J.H. Li and Y.F. Nie

金属学报(英文版) , 2001,
Abstract: Several typical methods for the recovery of Ni-Cd batteries are described in detail. Based on the comparing of hydrometallurgical and pyrometallurgical processes, the latter was selected as the suitable method for recycling Ni-Cd batteries in China.
Pulse Charging of Nickel Cadmium Batteries for Lost Capacity Recovery  [cached]
Ayodele O. Soge,Paul W. Lefley
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: This study presents an experimental investigation on the effectiveness of pulse recharging technique in recovering the lost capacity of nickel cadmium batteries (NiCad), through a comparison test with the conventional constant-current recharging technique. Scanning Electron Microscope (SEM) analysis has been carried out on the electrodes of both pulse recharged and conventionally recharged NiCad cells after a controlled experimental process to restore the lost capacity due to shallow cycling. The results show that the pulse recharging technique performed equally well with the conventional recharging method in improving the topologies of the cell electrodes and recovering the lost capacity of the NiCad cells. The causes of capacity loss in NiCad batteries have also been investigated and the results obtained established the claim that shallow cycling enhances large and dendritic crystalline growth on the cell electrodes.
A chemical assessment of freshness in stored adductor muscle from scallops
Massa, A.E.;Paredi, M.E.;Crupkin, M.;
Brazilian Journal of Chemical Engineering , 2003, DOI: 10.1590/S0104-66322003000200008
Abstract: the postmortem catabolism of adenosine triphosphate (atp) in cold-stored adductor muscles from scallops (zygochlamys patagónica) was studied. changes in the ph of stored muscles were also studied. the atp content increased for a short time after death and afterwards decreased up to 24 hr of storage. thereafter, the nucleotide level remained unchanged up to the end of storage. the adp content slightly decreased up to 48 hr and after that remained unchanged. the amp slowly accumulated to around 15% of the total nucleotide concentration when the atp decreased. small amounts of imp were detected in all samples. conversely, adenosine (ado) was not detected. inosine (hxr) increased slightly after 48 hr of storage and hypoxanthine (hx) increased significantly after 24 hr. the 260/250 absorbance ratio of muscle extracts and the ph of stored muscles fell sharply up to 24 hr and then decreased slowly up to the end of storage. the hypoxanthine concentration and the 260/250 absorbance ratio could be reliable indicators of storage age in adductor muscles from scallops.
A chemical assessment of freshness in stored adductor muscle from scallops  [cached]
Massa A.E.,Paredi M.E.,Crupkin M.
Brazilian Journal of Chemical Engineering , 2003,
Abstract: The postmortem catabolism of adenosine triphosphate (ATP) in cold-stored adductor muscles from scallops (Zygochlamys patagónica) was studied. Changes in the pH of stored muscles were also studied. The ATP content increased for a short time after death and afterwards decreased up to 24 hr of storage. Thereafter, the nucleotide level remained unchanged up to the end of storage. The ADP content slightly decreased up to 48 hr and after that remained unchanged. The AMP slowly accumulated to around 15% of the total nucleotide concentration when the ATP decreased. Small amounts of IMP were detected in all samples. Conversely, adenosine (Ado) was not detected. Inosine (HxR) increased slightly after 48 hr of storage and hypoxanthine (Hx) increased significantly after 24 hr. The 260/250 absorbance ratio of muscle extracts and the pH of stored muscles fell sharply up to 24 hr and then decreased slowly up to the end of storage. The hypoxanthine concentration and the 260/250 absorbance ratio could be reliable indicators of storage age in adductor muscles from scallops.
On accumulated spectrograms  [PDF]
Luís Daniel Abreu,Karlheinz Gr?chenig,José Luis Romero
Mathematics , 2014,
Abstract: We study the eigenvalues and eigenfunctions of the time-frequency localization operator $H_\Omega$ on a domain $\Omega$ of the time-frequency plane. The eigenfunctions are the appropriate prolate spheroidal functions for an arbitrary domain $\Omega$. Indeed, in analogy to the classical theory of Landau-Slepian-Pollak, the number of eigenvalues of $H_\Omega$ in $[1-\delta , 1]$ is equal to the measure of $\Omega$ up to an error term depending on the perimeter of the boundary of $\Omega$. Our main results show that the spectrograms of the eigenfunctions corresponding to the large eigenvalues (which we call the accumulated spectrogram) form an approximate partition ofunity of the given domain $\Omega $. We derive both asymptotic, non-asymptotic, and weak $L^2$ error estimates for the accumulated spectrogram. As a consequence the domain $\Omega$ can be approximated solely from the spectrograms of eigenfunctions without information about their phase.
Page 1 /100
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.