Reactive Diffusion upon Planar Dissolving Copper in Solder Melts

2011 ◽  
Vol 309-310 ◽  
pp. 127-134 ◽  
Author(s):  
Jaromír Drápala ◽  
Pavel Jopek ◽  
Daniel Petlák ◽  
Petr Harcuba ◽  
Petr Kubíček
Keyword(s):  
Interphase Boundary ◽  
Time Course ◽  
Solid Phase ◽  
Accurate Determination ◽  
Theoretical Description ◽  
Reactive Diffusion ◽  
Boundary Movement ◽  
Original Metal ◽  
Kinetics Of

Problems of reactive diffusion at a solid phase - melt contact were studied theoretically. The main intention was to calculate the time course of the solid phase dissolving in the case of planar dissolving. In our work we give heed especially to the dominating process, which is the solid metal A dissolving in solder melt B. During the dissolving, melt B saturates with metal A, and the process is influenced by convections which are characteristic for a given experimental configuration. A theoretical description of the kinetics of solid phase dissolving in the melt will be presented for the case of planar dissolving. The aim is to derive a relation for the interphase boundary movement (t) depending on time and a time course of growth of the element A concentration in the melt B. There are difficulties in accurate determination of the interphase boundary movement after heating of specimens for certain time intervals. It should be performed experimentally, since intermetallic phases are formed in original metal A both via diffusion and upon cooling and some phases segregate upon cooling of the solidifying melt. The main intention was to study experimentally the copper dissolving in melts of various solder alloys and the related reactive diffusion. We used pure Sn and Sn-Cu, Sn-Ag-Cu, Sn-Sb, Sn-Zn alloys as solder materials. Experiments aimed at the study of a Cu plate dissolving in the solder melt were carried out at various selected temperatures and times. The problems of reactive diffusion were studied both theoretically and experimentally and the problems that have to be solved preferably were emphasized. Concentration profiles of elements and thickness of layers of phases can be determined with SEM and X-ray microanalyses (WDX, EDX) of specimens after their diffusion heating.

Reactive Diffusion at the Cylindrical Dissolving of Copper in the Solder Melt

2011 ◽  
Vol 312-315 ◽  
pp. 387-392 ◽  
Author(s):  
Jaromír Drápala ◽  
Alena Struhařová ◽  
Daniel Petlák ◽  
Vlastimil Vodárek ◽  
Petr Kubíček
Keyword(s):  
Time Course ◽  
Solid Phase ◽  
Accurate Determination ◽  
Theoretical Description ◽  
Reactive Diffusion ◽  
Interface Boundary ◽  
Boundary Movement ◽  
Long Time ◽  
Melt Cooling

Problems of reactive diffusion at the solid phase and melt contact were studied theoretically and experimentally. The main intention was to calculate the time course of the solid phase dissolving in the case of cylindrical dissolving. These calculations were carried out on the assumption for the rate constant of dissolving K = const. In our work we give heed especially to the dominating process, which is the solid metal A dissolved in the melt B. During the dissolving the melt B saturates with the metal A and the process is influenced by convections which are characteristic for the given experimental configuration. A theoretical description of the kinetics of the solid phase dissolving in the melt will be presented for the case of cylindrical dissolving. The aim is to derive a relation for the interface boundary movement c(t) in dependence on time and a time course of growth of the element A concentration in the melt B. There are problems with accurate determination of the interface boundary movement after certain heating times of specimens, when it is observed experimentally, since intermetallic phases create in the original A metal at both the diffusion and cooling and some phases segregate at the solidifying melt cooling. The main intention was an experimental study of the copper dissolving in the tin melt. Experiments aimed to the determination of the Cu wires (diameters from 0.5 to 3.5 mm) dissolution in the solder melt were carried out at various selected temperatures and times. Rapid growth of phases in the metal A and determination of the thickness of layers with these phases pose considerable time demands to X-ray micro-analyses (WDX, EDX) of specimens after their long-time heating.

Study of the Reactive Diffusion in the Presence of Dissolution of Copper in the Solder Melts

2010 ◽  
Vol 297-301 ◽  
pp. 8-14 ◽  
Author(s):  
Jaromír Drápala ◽  
Petr Kubíček
Keyword(s):  
Rate Constant ◽  
Solid Phase ◽  
Accurate Determination ◽  
Intermetallic Phases ◽  
Theoretical Description ◽  
Reactive Diffusion ◽  
Fundamental Parameter ◽  
Interface Boundary ◽  
Boundary Movement ◽  
Metallic Cylinder

In this work we give heed especially to the dominating process which is the solid metal A dissolving in the melt B. During the dissolving, the melt B saturates with the metal A and the process is influenced by convections which are characteristic for the given experimental configuration. A theoretical description of the kinetics of the solid phase dissolving in melt will be presented for the case of planar and cylindrical dissolving. The aim is to derive a relation for the interface boundary (t) movement in dependence on time and a time course of growth of the element A concentration in the melt B. There are problems with an accurate determination of the interface boundary movement after certain heating times of specimens, when it is observed experimentally, since intermetallic phases create in the original A metal at both the diffusion and cooling and some phases segregate at the solidifying melt cooling. The rate constant is a fundamental parameter characterizing the dissolving rate at a certain configuration. We present a theoretical description of dissolving of a long metallic cylinder submerged into a melt column and relations for the rate constant determination from the time of the whole metallic cylinder dissolution are derived. In our experiments were performed in which Cu was dissolving in the Sn melt for a Cu cylinder (wire) diameters 0.8÷2.5 mm and the rate constant K (T = 350°C) was determined. Relationships between the solid phase dissolving rate, i.e. the solid phase interface boundary movement (t) in the melt and rates of growth of intermetallic phases in the metal A will be observed. This procedure enables to create surface and subsurface layers of regulated thickness in metallic materials by means of reactive diffusion.

scholarly journals In Vitro Evaluation of the Sensitivity of a Hyaluronic Acid PEG Cross-Linked to Bovine Testes Hyaluronidase

2018 ◽  
Vol 6 (1) ◽  
pp. 20-24 ◽  
Author(s):  
Nicola Zerbinati ◽  
Torello Lotti ◽  
Damiano Monticelli ◽  
Virginia Martina ◽  
Giovanna Cipolla ◽  
...  
Keyword(s):  
Hyaluronic Acid ◽  
Soft Tissue ◽  
Chemical Reaction ◽  
Time Course ◽  
Soft Tissue Augmentation ◽  
Facial Soft Tissue ◽  
Microplate Reader ◽  
Kinetics Of

Neauvia Intense is biocompatible, injectable hyaluronic acid (HA) filler PEG cross-linked for facial soft-tissue augmentation that provides volume to tissues. The aim of the present study is to evaluate the sensitivity of Neauvia Intense in hyaluronidase from bovine testes in a time-course analysis. The test is based on the colourimetric determination of the N-acetyl – D - glucosamine (NAG) released by the hyaluronidase in standardised conditions. The in vitro conditions involve the treatment of Neauvia Intense with a known concentration of the enzyme (6080U/ml). The NAG content was determined at different times to assess the kinetics of the degradation (1h, 3h, 6h, 24h, 48h, 72h, 120h, and 168h); the Ehrlich’s reagent was used for the colourimetric quantification, by the method described by Reissing and colleagues. The intensity of the violet colour developed after the chemical reaction was proportional to the NAG present in each sample. A microplate reader at 585 nm read the absorbance. The amount of NAG released by the product was proportional to the time of incubation with bovine hyaluronidase, reaching a plateau after 168 hours.

CATIONIC COPOLYMERIZATION OF ISOBUTYLENE WITH ISOPRENE: KINETICS OF THE PROCESS AND DETERMINATION OF KINETIC CONSTANTS

2015 ◽  
Vol 88 (4) ◽  
pp. 574-583 ◽  
Author(s):  
N. V. Ulitin ◽  
K. A. Tereshchenco ◽  
D. A. Shiyan ◽  
G. E. Zaikov
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Cationic Polymerization ◽  
Methyl Chloride ◽  
Theoretical Description ◽  
Kinetic Constants ◽  
Molecular Weight Characteristics ◽  
Cationic Copolymerization ◽  
Kinetics Of

ABSTRACT A theoretical description has been developed of the kinetics of isobutylene with isoprene (IIR) cationic polymerization in the environment of methyl chloride on aluminum trichloride as the catalyst. Based on experimental data on the kinetics of copolymerization (isobutylene conversion curve) and the molecular weight characteristics of the copolymer of IIR, kinetic constants for the process were found. Adequacy of the developed theoretical description of the kinetics of the IIR copolymerization process was confirmed by comparing the experimental molecular-weight characteristics calculated by this description, independent characteristics, and IIR unsaturation.

scholarly journals Development of a Sensitive and Reliable UHPLC-MS/MS Method for the Determination of Multiple Urinary Biomarkers of Mycotoxin Exposure

Toxins ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 193 ◽  
Author(s):  
Zhezhe Liu ◽  
Xiaoxue Zhao ◽  
Libiao Wu ◽  
Shuang Zhou ◽  
Zhiyong Gong ◽  
...  
Keyword(s):  
Human Urine ◽  
Solid Phase ◽  
Accurate Determination ◽  
Fumonisin B1 ◽  
High Sensitivity ◽  
Human Biomonitoring ◽  
Urine Samples ◽  
Specific Method ◽  
Alternariol Monomethyl Ether

A variety of mycotoxins from different sources frequently contaminate farm products, presenting a potential toxicological concern for animals and human. Mycotoxin exposure has been the focus of attention for governments around the world. To date, biomarkers are used to monitor mycotoxin exposure and promote new understanding of their role in chronic diseases. The goal of this research was to develop and validate a sensitive UHPLC-MS/MS method using isotopically-labeled internal standards suitable for accurate determination of 18 mycotoxin biomarkers, including fumonisins, ochratoxins, Alternaria and emerging Fusarium mycotoxins (fumonisin B1, B2, and B3, hydrolyzed fumonisin B1 and B2, ochratoxin A, B, and alpha, alternariol, alternariol monomethyl ether, altenuene, tentoxin, tenuazonic acid, beauvericin, enniatin A, A1, B, and B1) in human urine. After enzymatic digestion with β-glucuronidase, human urine samples were cleaned up using HLB solid phase extraction cartridges prior to instrument analysis. The multi-mycotoxin and analyte-specific method was validated in-house, providing satisfactory results. The method provided good linearity in the tested concentration range (from LOQ up to 25–500 ng/mL for different analytes), with R2 from 0.997 to 0.999. The limits of quantitation varied from 0.0002 to 0.5 ng/mL for all analytes in urine. The recoveries for spiked samples were between 74.0% and 133%, with intra-day precision of 0.5%–8.7% and inter-day precision of 2.4%–13.4%. This method was applied to 60 urine samples collected from healthy volunteers in Beijing, and 10 biomarkers were found. At least one biomarker was found in all but one of the samples. The high sensitivity and accuracy of this method make it practical for human biomonitoring and mycotoxin exposure assessment.

Determination of inorganic arsenic in rice by solid phase extraction and hydride generation atomic fluorescence spectrometry

2015 ◽  
Vol 7 (20) ◽  
pp. 8896-8900 ◽  
Author(s):  
Yatao Huang ◽  
Jihao Shan ◽  
Bei Fan ◽  
Yan He ◽  
Shuangmei Xia ◽  
...  
Keyword(s):  
Solid Phase ◽  
Low Cost ◽  
Accurate Determination ◽  
Hydride Generation ◽  
Inorganic Arsenic ◽  
Atomic Fluorescence Spectrometry ◽  
Food Crops ◽  
Total Arsenic ◽  
Atomic Fluorescence

Low-cost, simple methods are needed for accurate determination of iAs in food crops. Total arsenic (As) from rice was extracted and As5+ reduced to As3+. The combined As3+ was separated then quantified. This method appears suitable for general use due to its low cost.

Phenylboronic Acid Solid Phase Extraction Cleanup and Isotope Dilution Liquid Chromatography-Tandem Mass Spectrometry for the Determination of Florfenicol Amine in Fish Muscles

2015 ◽  
Vol 98 (3) ◽  
pp. 566-574 ◽  
Author(s):  
Della Wai-Mei Sin ◽  
Clare Ho ◽  
Yiu-Tung Wong
Keyword(s):  
Isotope Dilution ◽  
Solid Phase ◽  
Phenylboronic Acid ◽  
Accurate Determination ◽  
Internal Standard ◽  
Fish Muscles ◽  
Liquid Chromatography Tandem Mass ◽  
Cleanup Procedure ◽  
Acid Catalyzed

Abstract Florfenicol (FFC) residues in foods are regulated as the sum of florfenicol and its metabolites measured as florfenicol amine (FFA). An isotope dilution LC-MS/MS method utilizing phenylboronic acid (PBA) SPE cleanup is established for the accurate determination of FFA in fish muscles (i.e., salmon and tilapia) after acid catalyzed hydrolysis. Comparisons of the PBA SPE cleanup procedure with other cleanup procedures such as mixed-mode cationic (MCX) SPE and solid supported liquid–liquid extraction were performed. Quantification of FFA in fish muscles was accomplished by using matrix-matched calibration with FFA-D3 as the internal standard. The method was validated with FFA fortified fish muscles at three different levels (50, 100, and 200 μg/kg). Conversion of FFC to FFA by acid catalyzed hydrolysis was evaluated and found to be ≥88%. The recoveries of FFA in fish muscles at the three fortification levels ranged from 89 to 106%, and RSDs were ≤9% in all cases. The LOD values in salmon and tilapia muscles were 0.13 and 1.64 μg/kg, respectively. The LOQ values in salmon and tilapia muscles were 0.29 and 4.13 μg/kg, respectively. This method is suitable for the application in routine control of FFC in fishes according to its residue definition.

scholarly journals On-line solid phase microextraction derivatization for the sensitive determination of multi-oxygenated volatile compounds in air

2021 ◽  
Vol 14 (7) ◽  
pp. 4989-4999
Author(s):  
Esther Borrás ◽  
Luis A. Tortajada-Genaro ◽  
Milagro Ródenas ◽  
Teresa Vera ◽  
Thomas Speak ◽  
...  
Keyword(s):  
Solid Phase ◽  
Accurate Determination ◽  
High Volume ◽  
Automated System ◽  
Gas Chromatography Mass Spectrometry ◽  
Oxygenated Compounds ◽  
On Line ◽  
Secondary Aerosols ◽  
Hydroxy Aldehydes

Abstract. Multi-oxygenated volatile organic compounds are important markers of air pollution and precursors of ozone and secondary aerosols in both polluted and remote environments. Herein, their accurate determination was enhanced. The approach was based on an automated system for active sampling and on-fibre derivatization coupled with the gas chromatography–mass spectrometry (GC–MS) technique. The method capability was determined for different compound families, such as aldehydes, ketones, α-dicarbonyls, hydroxy-aldehydes, hydroxy-ketones, and carboxylic acids. A good accuracy (<7 %) was demonstrated from the results compared to Fourier-transform infrared spectroscopy (FTIR). Limits of detection (LODs) of 6–100 pptV were achieved with a time resolution lower than 20 min. The developed method was successfully applied to the determination of multi-oxygenated compounds in air samples collected during an intercomparison campaign (EUROCHAMP-2020 project). Also, its capability and accuracy for atmospheric monitoring was demonstrated in an isoprene ozonolysis experiment. Both were carried out in the high-volume outdoor atmospheric simulation chambers (EUPHORE, 200 m3). In summary, our developed technique offers near-real-time monitoring with direct sampling, which is an advantage in terms of handling and labour time for a proper quantification of trace levels of atmospheric multi-oxygenated compounds.

scholarly journals Headspace Solid Phase Microextraction Application for Pesticide Residues in Fruits and Vegetables

2016 ◽  
Vol 2 (2) ◽  
Author(s):  
Abookleesh L Frage , Almrhag M. Omar , Zatout M. Massoud
Keyword(s):  
Sample Preparation ◽  
Solid Phase Microextraction ◽  
Fruits And Vegetables ◽  
High Efficiency ◽  
Solid Phase ◽  
Accurate Determination ◽  
Chemical Properties ◽  
Extraction Process ◽  
Headspace Solid Phase Microextraction

Headspace solid phase microextraction, fundamental& principle with its application on the determination of various pesticides are reviewed in this article. Pesticides extraction as a sample preparation step prior to subsequent analysis is aimed to achieve a reliable and accurate determination of this contaminants residue in food. Fast and high efficiency extraction process with free solvent consumption and overall cost is achieved through headspace solid phase micro extraction. HSPME is an equilibrium process which depends on the physio-chemical properties of the analyte to be extracted. Sample preparation and extraction condition such as fiber coating, temperature, time etc, have a direct impact on the extraction efficiency and sensitivity of headspace technique.

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