A NEW TECHNIQUE FOR THE STUDY OF HIGH-POLYMER DEGRADATION REACTIONS

1963 ◽  
Vol 41 (2) ◽  
pp. 355-362 ◽  
Author(s):  
H. H. G. Jellinek ◽  
J. E. Clark
Keyword(s):  
Reaction System ◽  
Mechanical Vibrations ◽  
Maximum Displacement ◽  
Degradation Reactions ◽  
Electrical Transducer ◽  
Temperature Equilibrium ◽  
A New Technique ◽  
Set Up ◽  
Reaction Vessels ◽  
Closed Reaction System

A quartz spoon gauge, recording pressures automatically, is described. The gauge, representing a closed reaction system, can be used for investigations of the degradation of polymers. It has been tested by degrading polymethylmethacrylate over a temperature range of 300 to 400 °C. The important features of the gauge are as follows: (1) The pressure exerted by gases during degradation is continuously recorded at appropriate chart speeds via an electrical transducer (maximum displacement ± 0.038 cm; spoon gauges used in this work had sensitivities in the region of 0.035 cm/atm). (2) Only small quantities of polymers are needed; 20 to 40 mg of polymer in the form of films was deposited on the walls of the reaction vessels; however, much smaller samples could be used, the limit being given by mechanical vibrations set up in the system. (3) Temperature equilibrium between the reaction vessels and a thermostated bath is reached within about 30 seconds.Useful results for polymethylmethacrylate were obtained up to 400 °C, which is a temperature about 100° higher than that reached by previous workers, not neglecting the initial parts of the reactions. The reproducibility of the results has been indicated by average curves obtained from several runs at any one particular temperature and their standard deviations.

scholarly journals Bushmeat Species Identification: Recombinase Polymerase Amplification (RPA) Combined with Lateral Flow (LF) Strip for Identification of Formosan Reeves’ Muntjac (Muntiacus reevesi micrurus)

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 426
Author(s):  
Yun-Hsiu Hsu ◽  
Wei-Cheng Yang ◽  
Kun-Wei Chan
Keyword(s):  
Species Identification ◽  
Operating Time ◽  
Meat Products ◽  
Reaction System ◽  
Lateral Flow ◽  
Recombinase Polymerase Amplification ◽  
Food Allergies ◽  
Mitochondrial Cytochrome B ◽  
Meat Species ◽  
A New Technique

The identification of animal species of meat in meat products is of great concern for various reasons, such as public health, religious beliefs, food allergies, legal perspectives, and bushmeat control. In this study, we developed a new technique to identify Formosan Reeves’ muntjac in meat using recombinase polymerase amplification (RPA) in combination with a lateral flow (LF) strip. The DNA extracted from a piece of Formosan Reeves’ muntjac meat was amplified by a pair of specific primers based on its mitochondrial cytochrome b gene for 10 min at a constant temperature ranging from 30 to 45 °C using RPA. Using the specific probe added to the RPA reaction system, the amplified products were visualized on the LF strip within 5 min. The total operating time from quick DNA extraction to visualizing the result was approximately 30 min. The RPA-LF system we designed was efficient when using boiled, pan-fried, roasted, stir-fried, or stewed samples. The advantages of simple operation, speediness, and cost-effectiveness make our RPA-LF method a promising molecular detection tool for meat species identification of either raw or variously cooked Formosan Reeves’ muntjac meat. It is also possible to apply this method to identify the meat of other wildlife sources.

scholarly journals Evaluation of a symptom-triggered front-loading detoxification technique for alcohol dependence: A pilot study

2004 ◽  
Vol 28 (11) ◽  
pp. 407-410 ◽  
Author(s):  
Ed Day ◽  
Jaimin Patel ◽  
George Georgiou
Keyword(s):  
Pilot Study ◽  
Alcohol Dependence ◽  
Randomised Trial ◽  
Intervention Group ◽  
New Approach ◽  
Acute Psychiatric Wards ◽  
Alcohol Detoxification ◽  
A New Technique ◽  
Set Up ◽  
To Receive

Aims and MethodsA pilot study was set up to compare a symptom-triggered ‘front-loading’ detoxification technique with the usual fixed dosage method. A group of 23 in-patients with alcohol dependence were randomised to receive either the intervention technique using diazepam or the standard chlordiazepoxide taper over 10 days.ResultsThe intervention group received a mean dosage of 74 mg diazepam (equivalent to 222 mg chlordiazepoxide) compared with 700 mg chlordiazepoxide in those receiving usual treatment. There was no statistical difference in the severity of alcohol withdrawal symptoms in the two groups, and the intervention group were slightly more satisfied with their treatment than the group undergoing the usual detoxification treatment. Feedback from the nursing staff was positive towards the new approach but highlighted some potential problems for its wider implementation.Clinical ImplicationsIt was possible to use a simple randomised trial design to introduce a new technique for alcohol detoxification to a specialist unit. Symptom-triggered front-loading detoxification using diazepam was as effective as a standard taper technique in terms of withdrawal severity reduction, and was acceptable to both patients and staff. This is potentially a useful technique for busy acute psychiatric wards.

Carbohydrates in alkaline systems. II. Kinetics of the transformation and degradation reactions of cellobiose, cellobiulose, and 4-O-β-D-glucopyranosyl-D-mannose in 1 M sodium hydroxide at 22 °C

1969 ◽  
Vol 47 (21) ◽  
pp. 3957-3964 ◽  
Author(s):  
Donald J. MacLaurin ◽  
John W. Green
Keyword(s):  
Sulfuric Acid ◽  
Sodium Hydroxide ◽  
Column Chromatography ◽  
Rate Constants ◽  
Reaction Rate ◽  
Reaction System ◽  
Reaction Rate Constants ◽  
Degradation Reactions ◽  
Fructose 2 ◽  
Kinetics Of

Rates of isomerization, epimerization, and degradation reactions were measured for cellobiose (7), cellobiulose (8), and 4-O-β-D-glucopyranosyl-D-mannose (9) at 0.001 M in 1 M NaOH under N2 in the dark at 22 °C. Reaction system resolution was by column chromatography on anion resins in the borate form. Assay for D-glucose (1), D-fructose (2), D-mannose (3), and 7,8, and 9 was by continuous automated colorimetry of column effluent with orcinol–sulfuric acid as reagent. Reaction rate constants (h−1) found: k78 0.078, k79 0.0005, k7,10 0.002, k87 0.022, k89 0.003 k81 0.065, k8,12 0.023, k97 0.002, k98 0.013, k9,11 0.006 where 10,11, and 12 are other products than 1,2,3,7,8, and 9. Details for preparation of 8 and 9 are given.

scholarly journals Classification of complex Wishart matrices with a diffusion–reaction system guided by stochastic distances

2015 ◽  
Vol 373 (2056) ◽  
pp. 20150118 ◽  
Author(s):  
Luis Gomez ◽  
Luis Alvarez ◽  
Luis Mazorra ◽  
Alejandro C. Frery
Keyword(s):  
Reaction System ◽  
Classification Problem ◽  
Diffusion Reaction ◽  
Speckle Reduction ◽  
Discrimination Power ◽  
Diffusion Term ◽  
Polarimetric Synthetic Aperture Radar ◽  
Positive Weights ◽  
Set Up

We propose a new method for polarimetric synthetic aperture radar (PolSAR) imagery classification based on stochastic distances in the space of random matrices obeying complex Wishart distributions. Given a collection of prototypes and a stochastic distance d (.,.), we classify any random matrix X using two criteria in an iterative set-up. First, we associate X with the class which minimizes the weighted stochastic distance w m d ( X , Z m ), where the positive weights w m are computed to max- imize the class discrimination power. Second, we improve the result by embedding the classification problem into a diffusion–reaction partial differential system where the diffusion term smooths the patches within the image, and the reaction term tends to move the pixel values towards the closest class prototype. In particular, the method inherits the benefits of speckle reduction by diffusion-like methods. Results on synthetic and real PolSAR data show the performance of the method.

An Investigation of Mechanical Non-Sinusoidal Oscillation of Continuous Casting Mold

2011 ◽  
Vol 264-265 ◽  
pp. 337-342 ◽  
Author(s):  
Xing Zhong Zhang ◽  
Hong Tao Zhu ◽  
A. Kiet Tieu ◽  
Hai Bo Xie ◽  
Xiao Zhong Du ◽  
...  
Keyword(s):  
Continuous Casting ◽  
New Technique ◽  
Maintenance Cost ◽  
Sinusoidal Oscillation ◽  
Operational Parameters ◽  
Continuous Casting Mold ◽  
Casting Mold ◽  
Sinusoidal Oscillations ◽  
A New Technique ◽  
Set Up

In this paper, a new technique to set up non-sinusoidal oscillations of the mold in continuous casting is presented. The waveform functions of this non-sinusoidal oscillation technique and operational parameters are analyzed and the design to realize the non-sinusoidal oscillation of mold is presented. It is anticipated that this technique will be widely applied as it has many advantages such as lower investment and maintenance cost, simple equipment which is easy to manufacture and maintain.

Über eine neue Präparationstechnik in der Feststoffchemie, II Hochdruck-Hochtemperatursynthesen mit CO2 -Laser / A New Preparative Technique in Solid State Chemistry, II High Pressure -High Temperature Reactions with CO2-Lasers

1979 ◽  
Vol 34 (3) ◽  
pp. 375-377 ◽  
Author(s):  
Hk. Müller-Buschbaum ◽  
H. Pausch
Keyword(s):  
High Pressure ◽  
Solid State ◽  
Solid State Reactions ◽  
Solid State Chemistry ◽  
Co2 Lasers ◽  
High Pressure High Temperature ◽  
High Oxygen Pressure ◽  
High Temperature Reactions ◽  
A New Technique ◽  
Set Up

Abstract A new technique to realize solid state reactions under high oxygen pressure is reported. This method is based on the use of CO2-Laser radiation in combination with autoclave technique. The experimental set-up is described.

Boundary Element Analysis of Coupled Continuum and Skeletal Structures

2007 ◽  
Vol 10 (4) ◽  
pp. 415-438
Author(s):  
Youssef F. Rashed
Keyword(s):  
Boundary Element ◽  
Main Idea ◽  
Element Analysis ◽  
Skeletal Structures ◽  
Stiffness Matrices ◽  
Assembly Technique ◽  
A New Technique ◽  
Set Up ◽  
The Continuum ◽  
Element Method

This paper presents a new technique for solving coupled continuum and skeletal structures. The technique is based on employing the well-known flexibility and stiffness methods within the boundary element method (BEM). The analyzed problem is divided into: continuum parts, which are modeled using the BEM and skeletal parts which are modeled using the flexibility or stiffness methods. The main idea of the presented technique is to set up a methodology to generate flexibility or stiffness matrices for the continuum parts using the BEM. To do so, several flexibility and stiffness models are developed. The developed technique is tested on three problems. Results are compared to those obtained from the finite element method (FEM) to show the validity of the developed technique. The present technique gains both advantages of the BEM and the FEM as it allows boundary-only discretization for the continuum parts and uses the banded assembly technique of FEM for the overall structure.

Curve Fitting Using Logarithmic Function for Sea Bed Logging Data

2016 ◽  
Vol 13 (10) ◽  
pp. 7448-7454
Author(s):  
Hanita Daud ◽  
Radzuan Razali ◽  
M. Ridhwan O Zaki ◽  
Afza Shafie
Keyword(s):  
Curve Fitting ◽  
Sea Water ◽  
Research Work ◽  
Low Frequency ◽  
Skin Depth ◽  
High Resistivity ◽  
Water And Sediment ◽  
Sea Bed ◽  
A New Technique ◽  
Set Up

The aim of this research work is to conduct curve fitting using mathematical equations that relate location of the hydrocarbon (HC) at different depths to different frequencies. COMSOL MultiPhysics software was used to generate models of the seabed logging technique which consists of air, sea water, and sediment and HC layer. Seabed Logging (SBL) is a technique to find the resistive layers under seabed by transmitting low frequency of EM waves through sea water and sediment. As HC is known to have high resistivity which is about 30–500 Ωm, EM waves will be guided and reflected back and detected by the receiver that are placed on the seafloor. In SBL, low frequency is used to obtain greater wavelength which allows EM waves to penetrate at longer distance and each frequency used has different skin depth. The frequencies used in this project were 0.5 Hz, 0.25 Hz, 0.125 Hz and 0.0625 Hz and the depths of the HC were varied from 1000 m to 3000 m with increment of 250 m. Data generated from COMSOL software was extracted for the set up with and without HC and trend lines using logarithmic functions were developed and R2 were calculated for each equation and curve. The calculated R2 was compared between data with HC to no HC at each depth and it was found that the calculated R2 values were very well fitted for deeper HC depth. This indicates that as depth of HC is higher, it is difficult to distinguish data with and without HC presence; and perhaps a new technique can be explored.

scholarly journals Production, Purification, and Identification of Cholest-4-en-3-one Produced by Cholesterol Oxidase from Rhodococcus sp. in Aqueous/Organic Biphasic System

2015 ◽  
Vol 8s1 ◽  
pp. BCI.S21580 ◽  
Author(s):  
Ke Wu ◽  
Wei Li ◽  
Jianrui Song ◽  
Tao Li
Keyword(s):  
Cholesterol Oxidase ◽  
Enzymatic Reaction ◽  
Reaction System ◽  
Phase System ◽  
Separation And Purification ◽  
Two Phase ◽  
Whole Cells ◽  
Steroid Drugs ◽  
Set Up ◽  
The Cost

Cholest-4-en-3-one has positive uses against obesity, liver disease, and keratinization. It can be applied in the synthesis of steroid drugs as well. Most related studies are focused on preparation of cholest-4-en-3-one by using whole cells as catalysts, but production of high-quality cholest-4-en-3-one directly from cholesterol oxidase (COD) using an aqueous/organic two-phase system has been rarely explored. This study set up an enzymatic reaction system to produce cholest-4-en-3-one. We developed and optimized the enzymatic reaction system using COD from COX5-6 (a strain of Rhodococcus) instead of whole-cell biocatalyst. This not only simplifies and accelerates the production but also benefits the subsequent separation and purification process. Through extraction, washing, evaporation, column chromatography, and recrystallization, we got cholest-4-en-3-one with purity of 99.78%, which was identified by nuclear magnetic resonance, mass spectroscopy, and infrared spectroscopy. In addition, this optimized process of cholest-4-en-3-one production and purification can be easily scaled up for industrial production, which can largely decrease the cost and guarantee the purity of the product.

Design and Analysis of Hydraulic Pumping Units

2007 ◽  
Author(s):  
Guixi Li ◽  
Rujian Ma ◽  
Jungang Wang
Keyword(s):  
Dynamic Response ◽  
Head Movement ◽  
Dynamic Stress ◽  
Dynamic Performance ◽  
The Other ◽  
Mechanical Vibrations ◽  
Maximum Displacement ◽  
Sucker Rod ◽  
Pumping Unit ◽  
Pumping Units

The dynamic performance of hydraulic beam pumping units was analyzed in this paper by using the theory of mechanical vibrations. The house-head movement of the pumping unit is mainly uniform, except the alternation period of upper- and down-strokes. Under the action of the house-head movement, the vibration of the system, the sucker-rod and, furthermore, the dynamic stress will be induced. The results indicate that the movement of the downhole pump includes two parts. One is the movement following the horse-head. The other is the dynamic response excited by the support movement. When the parameters of the system are selected reasonably, over-stroke of the pump will appear. This is because the movement of the hydraulic piston obeys a particular law. The maximum displacement increases, and the maximum dynamic stress decreases with depth. The changing of maximum dynamic stress with depth obeys quadratic law.

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