Effects of formaldehyde concentration on the bond quality of peanut hull extract copolymer resins

1982 ◽  
Vol 21 (3) ◽  
pp. 450-454 ◽  
Author(s):  
Chia M. Chen
Keyword(s):  
Formaldehyde Concentration ◽  
Bond Quality ◽  
Hull Extract ◽  
Peanut Hull

Experimental investigation of 0.6 in. diameter strand lifting loops

PCI Journal ◽  
2021 ◽  
Vol 66 (2) ◽  
pp. 71-87
Author(s):  
Sandip Chhetri ◽  
Rachel A. Chicchi ◽  
Andrew E. N. Osborn
Keyword(s):  
Failure Modes ◽  
Concrete Strength ◽  
Bond Stress ◽  
Pullout Capacity ◽  
Bond Quality ◽  
Concrete Blocks ◽  
Mohs Hardness ◽  
Side Face ◽  
Pullout Failure

Very little experimental data have been published relating to the pullout capacity of prestressing strand lifting loops. To address this gap in knowledge, 13 pullout tests were conducted on strand lifting loops with 0.6 in. (15.24 mm) diameter, 270 ksi (1860 MPa) strand. Straight and bent orientations were tested for single loops at different embedment depths. Loops were embedded in 12 in. (304.8 mm) wide and 44 in. (1117.6 mm) deep concrete blocks and subjected to monotonic, static loading until failure. Marginal bond quality of the strand (18.2 kip [81 kN]), Mohs hardness (3.6), and concrete strength (3000 psi [20.7 MPa]) resulted in an average bond stress value of 400 psi (2758 kPa) at failure. Most tests exhibited pullout failure modes and adequate ductility. Three loops tested at 32 in. (812.8 mm) embedment with 6 in. (152.4 mm), 90-degree bends experienced brittle side-face blowout failures. These failures were due to inclination of the lifting, which led to a reduced edge distance. A safe uniform bond stress of 199 psi (1372 kPa) is recommended for 0.6 in. diameter strand.

NEW METHOD FOR DETERMINING THE FORMALDEHYDE CONTENT IN CORK PLUGS IN ACCORDANCE WITH THE REQUIREMENTS OF THE EURASIAN ECONOMIC UNION

2020 ◽  
Author(s):  
Л.Э. Чемисова ◽  
М.Г. Марковский ◽  
Н.М. Агеева ◽  
О.Н. Шелудько
Keyword(s):  
Low Cost ◽  
Alcoholic Beverages ◽  
Formaldehyde Concentration ◽  
Uv Detector ◽  
Formaldehyde Content ◽  
Safety Requirements ◽  
Eurasian Economic Union ◽  
Economic Union ◽  
Electrokinetic Capillary Chromatography

Вхождение Российской Федерации в Евразийский экономический союз обусловило ужесточение требований, предъявляемых к показателям безопасности алкогольной продукции, в том числе к упаковочным средствам. Алкогольные напитки хранятся и даже выдерживаются в упаковке, поэтому укупорочный материал – корковая пробка может существенно влиять на качество напитка. В связи с этим к корковым пробкам предъявляются требования безопасности в форме контроля содержания формальдегида. Существующие способы его идентификации достаточно трудоемки и весьма затратны, а также предусматривают использование дорогостоящего оборудования. Предлагаемый метод определения содержания формальдегида, выделяющегося из корковых пробок в модельные среды, разработан на основе мицеллярной электрокинетической капиллярной хроматографии с использованием процесса дериватизации контролируемого соединения раствором 2,4-динитрофенилгидразин (2,4-ДНФГ) в ацетонитриле, содержащем 5% уксусной кислоты. Для исследования использовали систему Капель 105, снабженную УФ-детектором с переменной длиной волны, кварцевые капилляры диаметром 75 мкм и общей длиной 60 см (50,5 см до детектора). Рабочие растворы формальдегида готовили ежедневно путем соответствующего разбавления образцов исходного раствора водой. Калибровочные графики были рассчитаны для шести концентраций – 2, 5, 10, 20, 40 и 100 мг/л стандартов в двух повторностях. В образцы – модельные среды, полученные при исследовании образцов корковых пробок, добавляли определенное количество стандартного раствора формальдегида и проводили процедуру дериватизации. УФ-детектирование производных 2,4-ДНФГ проводили при длине волны 360 нм. Результаты апробации метода представлены на электрофореграммах. Получена линейная зависимость между площадью пика и концентрацией формальдегида (R2 = 0,99). Разработанный метод определения содержания формальдегида малозатратен, отличается простой и высокой точностью и может быть рекомендован в качестве инструмента контроля безопасности корковых пробок в соответствии со стандартами Евразийского экономического союза. The entry of the Russian Federation into the Eurasian economic Union has led to stricter requirements for the safety indicators of alcoholic beverages, including packaging products. Alcoholic beverages are stored and even aged in the packaging, so the corking material – cork plugs can significantly affect the quality of the drink. In this regard, cork plugs are subject to safety requirements in the form of formaldehyde control. Existing methods for identifying it are quite time-consuming and very expensive, and also involve the use of expensive equipment. The proposed method for determining the content of formaldehyde released from cortical plugs into model media was developed on the basis of micellar electrokinetic capillary chromatography using the process of derivatization of a controlled compound with a solution of 2,4-dinitrophenylhydrazine (2,4-DNPH) in acetonitrile containing 5% acetic acid. System Kapel 105 equipped with a UV-detector with a variable wavelength, quartz capillaries with a diameter of 75 microns and a total length of 60 cm (50,5 cm to the detector) were used for the study. Working solutions of formaldehyde were prepared daily by appropriately diluting the samples of the initial solution with water. Calibration graphs were calculated for six concentrations – 2, 5, 10, 20, 40 and 100 mg/l standards in two repetitions. A certain amount of standard formaldehyde solution was added to the sample – model media obtained during the study of cork plugs samples and a derivatization procedure was performed. UV detection of 2,4-DNPH derivatives was performed at a wavelength of 360 nm. The results of testing the method are presented on electrophoregrams. A linear relationship was obtained between the peak area and the formaldehyde concentration (R2 = 0,99). The developed method for determining the formaldehyde content is low-cost, simple and highly accurate, and can be recommended as a tool for monitoring the safety of cork plugs in accordance with the standards of the Eurasian economic Union.

Bond Quality of Laminated Wood Made from Surian (Toona sinensis Roem) and Sengon (Paraserianthes falcataria (L.) Nielsen)

2017 ◽  
Vol 18 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Eka Mulya Alamsyah ◽  
Ihak Sumardi ◽  
Sutrisno . ◽  
Atmawi Darwis ◽  
Yoyo Suhaya
Keyword(s):  
Bond Quality ◽  
Paraserianthes Falcataria ◽  
Toona Sinensis

Effect of double-layer application on bond quality of adhesive systems

2018 ◽  
Vol 77 ◽  
pp. 501-509 ◽  
Author(s):  
Satoshi Fujiwara ◽  
Toshiki Takamizawa ◽  
Wayne W. Barkmeier ◽  
Akimasa Tsujimoto ◽  
Arisa Imai ◽  
...  
Keyword(s):  
Double Layer ◽  
Adhesive Systems ◽  
Bond Quality

How to Evaluate the Effect of Mud Cake on Cement Bond Quality of Second Interface?

2007 ◽  
Author(s):  
Ma Yong ◽  
Cui Mao Rong ◽  
Guo Yang ◽  
Shi Qing ◽  
Li Li
Keyword(s):  
Bond Quality ◽  
Mud Cake ◽  
Cement Bond Quality

Multi-Resolution Analysis of the Acousto-Ultrasonic Testing Signal for Composite Material Detection

2011 ◽  
Vol 65 ◽  
pp. 108-112
Author(s):  
Bin Jing ◽  
Chunan Ai ◽  
Yu Liu
Keyword(s):  
Adaptive Filtering ◽  
Characteristic Frequency ◽  
Composite Shell ◽  
Bond Quality ◽  
Multi Resolution Analysis ◽  
Material Detection ◽  
Resolution Analysis ◽  
Testing Signal ◽  
Stress Wave Factor

The AU technique is employed in this paper to test the specimen which is made up of composite shell and adiabatic layer; the noise in the tested signal is reduced by adaptive filtering; Multi-resolution analysis of the signal is achieved by wavelet transform. By comparing the ratio of the energy of signal in different frequency zones to the total energy, the characteristic frequency zone of the signal is gained. The characteristic frequency zone of the signal from specimen is evaluated by energy integral Stress Wave Factor (SWF). Flaws are found effectively, and the size of flaw can be evaluated qualitatively. The validity of AU test for bond quality of the structure is approved in the experiments.

scholarly journals Application of stress based NDT methods for concrete repair bond quality control

2015 ◽  
Vol 63 (1) ◽  
pp. 77-85 ◽  
Author(s):  
A. Garbacz
Keyword(s):  
Stress Waves ◽  
Test Method ◽  
Repair System ◽  
Repair Material ◽  
Bond Quality ◽  
Substrate Roughness ◽  
Concrete Repair ◽  
Factors Affecting ◽  
Field Assessment

Abstract Adhesion in repair systems is one of the most important factors affecting their durability. Elaboration of a reliable nondestructive test method to perform an adhesion mapping is one of the most important tasks. A majority of NDT methods applicable for the assessment of concrete structures are based on the propagation of various types of stress waves. In this paper, the influence of the repair material type (polymer-cement or polymer) and quality of the concrete substrate (roughness, microcracking, not cleaned surface) upon propagation of stress waves in a repair system was studied in view of developing a reliable NDT procedure for the field assessment of bond quality in concrete repairs.

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