Entrapment of impurities inside a Cold Trap: A purification process for removal of corrosion impurities from molten Pb-16Li

2021 ◽  
Author(s):  
Ankush V Deoghar ◽  
Abhishek Saraswat ◽  
Hardik Tailor ◽  
Shrikant Verma ◽  
Sandeep Gupta ◽  
...  
Keyword(s):  
Cold Trap ◽  
Purification Process

Reduction of Specimen Contamination in Electron-Beam Instruments

1976 ◽  
Vol 34 ◽  
pp. 576-577
Author(s):  
G. Lehmpfuhl ◽  
P. J. Smith
Keyword(s):  
Electron Beam ◽  
Cold Trap ◽  
Beam Diameter ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Hydrocarbon Molecules ◽  
Electron Microscopes ◽  
Combination Of Methods ◽  
Convergent Beam ◽  
Very High

Specimens being observed with electron-beam instruments are subject to contamination, which is due to polymerization of hydrocarbon molecules by the beam. This effect becomes more important as the size of the beam is reduced. In convergent-beam studies with a beam diameter of 100 Å, contamination was observed to grow on samples at very high rates. Within a few seconds needles began forming under the beam on both the top and the underside of the sample, at growth rates of 400-500 Å/s, severely limiting the time available for observation. Such contamination could cause serious difficulty in examining a sample with the new scanning transmission electron microscopes, in which the beam is focused to a few angstroms.We have been able to reduce the rate of contamination buildup by a combination of methods: placing an anticontamination cold trap in the sample region, preheating the sample before observation, and irradiating the sample with a large beam before observing it with a small beam.

A conduction-cooled stage for high-resolution Cryo-SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1282-1283
Author(s):  
John G. Sheehan
Keyword(s):  
High Resolution ◽  
Liquid Nitrogen ◽  
Mechanical Stability ◽  
Cooling System ◽  
Cold Trap ◽  
Nitrogen Gas ◽  
Particulate Suspensions ◽  
Advantages And Disadvantages ◽  
Convection Cooling ◽  
Styrene Butadiene

The goal is to examine with high resolution cryo-SEM aqueous particulate suspensions used in coatings for printable paper. A metal-coating chamber for cryo-preparation of such suspensions was described previously. Here, a new conduction-cooling system for the stage and cold-trap in an SEM specimen chamber is described. Its advantages and disadvantages are compared to a convection-cooling system made by Hexland (model CT1000A) and its mechanical stability is demonstrated by examining a sample of styrene-butadiene latex.In recent high resolution cryo-SEM, some stages are cooled by conduction, others by convection. In the latter, heat is convected from the specimen stage by cold nitrogen gas from a liquid-nitrogen cooled evaporative heat exchanger. The advantage is the fast cooling: the Hexland CT1000A cools the stage from ambient temperature to 88 K in about 20 min. However it consumes huge amounts of liquid-nitrogen and nitrogen gas: about 1 ℓ/h of liquid-nitrogen and 400 gm/h of nitrogen gas. Its liquid-nitrogen vessel must be re-filled at least every 40 min.

Analysis of galanthamine and related alkaloids in plant extracts and during the purification process by GC-MS

Planta Medica ◽  
2007 ◽  
Vol 73 (09) ◽  
Author(s):  
S Berkov ◽  
C Codina ◽  
F Viladomat ◽  
J Bastida
Keyword(s):  
Plant Extracts ◽  
Purification Process

PENGARUH PELARUT KLOROFORM DALAM PEMURNIAN GLISEROL DENGAN PROSES ASIDIFIKASI ASAM KLORIDA

2016 ◽  
Vol 5 (3) ◽  
pp. 38-43
Author(s):  
Windi Monica Surbakti ◽  
Gerson Rico M.H ◽  
Mersi Suriani Sinaga
Keyword(s):  
Fatty Acid ◽  
Volume Ratio ◽  
Biodiesel Production ◽  
Extraction Time ◽  
Glycerol Concentration ◽  
Purification Process ◽  
Soap Content ◽  
Test Volume ◽  
Base Content ◽  
Water Salt

Glycerol as a byproduct of biodiesel production was approximately formed 10% of the biodiesel weight. Impurities which contained in the glycerol such as catalyst, soap, methanol, water, salt, and matter organic non glycerol (MONG) have a significant effect on the glycerol concentration. So, it is necessary to treat the impurities. The purpose of this study is to know the effect of chloroform to glycerol purification process with acidification method using hydrochloric acid as pretreatment process. This research was begun with acid addition to the glycerol to neutralize the base content and to split the soap content into free fatty acid and salt, that are more easily separated from glycerol. Then the process was continued with extraction by the solvent chloroform using the variable of test volume ratio (v/v) (1:1, 1:1.5, 1:2)  and the extraction time (20, 40, and 60 minutes). The results showed that the more volume of solvent used, gave less extraction time to produce high purity of glycerol. The highest purity produced in this study amounted to 90,9082% is obtained at the ratio of the volume solvent (v/v) 1:1 with extraction time 60 minutes.

PEG1000 as a Low Melting and Ecofriendly Solvent for Air Oxidative and Catalyst Free 2,4-Disubstitute Quinazoline Synthesis

2020 ◽  
Vol 17 (9) ◽  
pp. 709-716
Author(s):  
Ebrahim Saeedian Moghadam ◽  
Shahrzad Ghafary ◽  
Mohsen Amini
Keyword(s):  
Melting Point ◽  
High Yield ◽  
Purification Process ◽  
Poly Ethylene Glycol ◽  
Free Condition ◽  
Catalyst Free ◽  
Privileged Scaffold ◽  
Quinazoline Derivatives ◽  
Poly Ethylene ◽  
Work Up

With regard to the importance of quinazoline as a privileged scaffold, herein we report the synthesis of twenty seven 2,4-disubstitute quinazoline derivatives in a new catalyst free condition. In the current work, poly ethylene glycol (PEG1000) as an inexpensive, very simple commercially available, ecofriendly and low melting point solvent was used. Air bubbling, a green oxidant, for oxidation purpose was also used. This is the first report about using PEG1000 as a solvent simultaneously with air bubbling as oxidant in quinazoline synthesis. All of the compounds 1-27 were synthesized in high yield with very simple work up and purification process without using column chromatography. All the structures were confirmed using 1H NMR, 13C NMR, IR, MS and elemental analysis.

Separation of 138Cs or 89Rb from fission products using cold trap

2014 ◽  
Vol 304 (2) ◽  
pp. 655-660
Author(s):  
Lijun Xu ◽  
Hongsheng Ye ◽  
Min Lin ◽  
Wen Xia ◽  
Kesheng Chen ◽  
...  
Keyword(s):  
Fission Products ◽  
Cold Trap

scholarly journals Leaching and solvent extraction purification of zinc from Mehdiabad complex oxide ore

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Faraz Soltani ◽  
Hossna Darabi ◽  
Reza Aram ◽  
Mahdi Ghadiri
Keyword(s):  
Solvent Extraction ◽  
Environmental Pollution ◽  
Central Composite Design ◽  
Complex Oxide ◽  
Hydrometallurgical Process ◽  
Purification Process ◽  
Optimum Conditions ◽  
Leaching Experiments ◽  
Central Composite ◽  
Sulphuric Acid Concentration

AbstractAn integrated hydrometallurgical process was used for the zinc leaching and purification from a zinc ore containing 9.75 wt% zinc. The zinc minerals in the ore were hemimorphite, willemite, and calcophanite. Main gangue minerals were quartz, goethite, hematite, and calcite. Central composite design (CCD) method was used to design leaching experiments and the optimum conditions were found as follows: 30% of solid fraction, 22.05% sulphuric acid concentration, and the leaching temperature of 45 °C. The PLS containing 35.07 g/L zinc, 3.16 g/L iron, and 4.58 g/L manganese impurities was produced. A special purification process including Fe precipitation and Zn solvent extraction was implemented. The results showed that after precipitation of iron, Zn extraction of 88.5% was obtained with the 2 stages extraction system composed of 30 vol% D2EHPA as extractant. The overall Zn recovery from the ore was 71.44%. Therefore, an appropriate solution containing 16.6 g/L Zn, 0.05 g/L Fe, and 0.11 g/L Mn was prepared for the electro-winning unit without using the roasting and calcination steps (conventional method), which result in environmental pollution.

Gram-scale production of sugar nucleotides and their derivatives

2021 ◽  
Author(s):  
Shuang Li ◽  
shuaishuai wang ◽  
Yaqian Wang ◽  
Jingyao Qu ◽  
Xianwei Liu ◽  
...  
Keyword(s):  
Scale Production ◽  
Purification Process ◽  
Selective Precipitation ◽  
Sugar Nucleotides ◽  
Production Strategy

Here, we report a practical sugar nucleotides production strategy that combined high-concentrated multienzyme catalyzed reaction and a robust chromatography-free selective precipitation purification process. Twelve sugar nucleoitdes were synthesized at gram-scale...

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