scholarly journals Determination of optimal reaction temperature and hydrogen amount for propylene polymerization by a mathematical model

2019 ◽  
Vol 68 (3-4) ◽  
pp. 119-127 ◽  
Author(s):  
Gholam Hossain Varshouee ◽  
Amir Heydarinasab ◽  
Ali Vaziri ◽  
Seyed Mehdi Ghafelebashi Zarand
Keyword(s):  
Reaction Temperature ◽  
Average Molecular Weight ◽  
Propylene Polymerization ◽  
Process Conditions ◽  
Adequate Model ◽  
Natta Catalyst ◽  
Optimal Reaction Temperature ◽  
The Relationship ◽  
Optimal Reaction

Regarding the complexity of Ziegler-Natta catalyst kinetics in polypropylene polymerization, so far, there is no adequate model to determine the best process conditions for predicting average molecular weight and dispersity as the most crucial final product properties index. Consequently, a validated model has been developed which describes the relationship between the kinetic model and the existing gap using the polymer moment balance approach. It was concluded that increasing reaction temperature and hydrogen amount are useful and improve the final product indices to a certain limit, but afterwards they have harmful effects on the indices.

scholarly journals A Mathematical Model for Investigating the Effect of Reaction Temperature and Hydrogen Amount on the Catalyst Yield during Propylene Polymerization

2019 ◽  
Vol 68 (7-8) ◽  
pp. 269-280 ◽  
Author(s):  
Gholam Hossain Varshouee ◽  
Amir Heydarinasab ◽  
Ali Vaziri ◽  
Seyed Mehdi Ghafelebashi Zarand
Keyword(s):  
Mathematical Model ◽  
Reaction Temperature ◽  
Propylene Polymerization ◽  
Process Conditions ◽  
Catalytic Potential ◽  
Natta Catalyst ◽  
Balance Technique ◽  
Laboratory Scale Reactor ◽  
Basic And Applied Research ◽  
New Formulation

In this study, the effect of reaction temperature and hydrogen amount, as the most effective process variables on the Ziegler-Natta catalysts yield during propylene polymerization, was investigated with the aid of a validated mathematical model. The approach applied in this modelling was the <i>polymer moment balance technique</i> (<i>population balance approach</i>) derived from the statistics expected value. The model was coded in MATLAB<sup>®</sup> & Simulink<sup>®</sup>, and then validated by experimental data coming from a laboratory-scale reactor. The main target of this study was to gain considerable insight into Ziegler-Natta catalyst performance against variables change. The model might be applicable for catalyst makers to evaluate and improve their catalysts, and could also be useful for process chemical engineers to easily operate the plant, replace new catalyst, optimise process conditions, generate new formulation for a new grade, and use maximum catalytic potential. Accordingly, the model could be applied in basic and applied research in this field.

Hydrothermal Synthesis of Well-Aligned ZnO Nanorod Arrays on Silicon

2013 ◽  
Vol 669 ◽  
pp. 302-306
Author(s):  
Tian Ning Xu ◽  
Zhong Lu ◽  
Cheng Hua Sui ◽  
Hui Zhen Wu
Keyword(s):  
Reaction Temperature ◽  
Zno Nanorods ◽  
Visible Region ◽  
Zno Nanorod ◽  
Nanorod Arrays ◽  
Zno Nanorod Arrays ◽  
X Ray Diffraction ◽  
Si Substrates ◽  
Optimal Reaction Temperature ◽  
Optimal Reaction

Zinc oxide (ZnO) nanorod arrays were fabricated on ZnO:Al seeded Si substrates with various reaction temperatures using a low temperature hydrothermal method. The morphology and structure of ZnO nanorod arrays were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It reveals that the ZnO nanorods grow vertically on Si surface with (002) preferential orientation. The transmittance spectra show the ZnO nanorod arrays fabricated at low temperatures have high transmittance in the visible region and decrease with reaction temperature increasing. Moreover, the same trend was also observed in the reflectance spectra of the ZnO nanorod arrays. The optimal reaction temperature is of 120 °C for ZnO nanorod arrays with high transmittance (~80%) and low reflectance (~10%) in the visible region. The superior optical properties make ZnO nanorod arrays promising for applications as transparent electrodes.

Thromboplastin Related Differences in the Determination of International Normalised Ratio: A Cause for Concern?

1994 ◽  
Vol 72 (03) ◽  
pp. 426-429 ◽  
Author(s):  
S Kitchen ◽  
I D Walker ◽  
T A L Woods ◽  
F E Preston
Keyword(s):  
Patient Management ◽  
External Quality Assessment ◽  
Oral Anticoagulant Therapy ◽  
Warfarin Dosage ◽  
External Quality ◽  
External Quality Assessment Scheme ◽  
International Normalised Ratio ◽  
The Uk ◽  
The Relationship

SummaryWhen the International Normalised Ratio (INR) is used for control of oral anticoagulant therapy the same result should be obtained irrespective of the laboratory reagent used. However, in the UK National External Quality Assessment Scheme (NEQAS) for Blood Coagulation INRs determined using different reagents have been significantly different.For 18 NEQAS samples Manchester Reagent (MR) was associated with significantly lower INRs than those obtained using Diagen Activated (DA, p = 0.0004) or Instrumentation Laboratory PT-Fib HS (IL, p = 0.0001). Mean INRs for this group were 3.15, 3.61, and 3.65 for MR, DA, and IL respectively. For 61 fresh samples from warfarin-ised patients with INRs of greater than 3.0 the relationship between thromboplastins in respect of INR was similar to that observed for NEQAS data. Thus INRs obtained with MR were significantly lower than with DA or IL (p <0.0001). Mean INRs for this group were 4.01, 4.40, and 4.59 for MR, DA, and IL respectively.We conclude that the differences between INRs measured with the thromboplastins studied here are sufficiently great to influence patient management through warfarin dosage schedules, particularly in the upper therapeutic range of INR. There is clearly a need to address the issues responsible for the observed discrepancies.

Modern determinants of endometrium hyperplastic processes pathogenesis

2016 ◽  
pp. 137-142
Author(s):  
V.O. Benyuk ◽  
◽  
V.M. Goncharenko ◽  
T.R. Nykoniuk ◽  
◽  
...  
Keyword(s):  
Conservative Therapy ◽  
Solid Phase ◽  
Research Direction ◽  
Immunohistochemical Method ◽  
Results Of Treatment ◽  
Treatment And Prevention ◽  
Receptor Phenotype ◽  
The Relationship ◽  
Endometrial Proliferation

The objective: to еxplore the relationship between the activity of endometrial proliferation and the state of the local immune response in the uterus in the conditions berprestasi process. Patients and methods. Examined 228 women of reproductive and perimenopausal age with endometrial pathology using ultrasound and then performing hysteroresectoscopy. Determination of the concentrations of the cytokines IL-1, IL-2, IL-6 and TNF was performed by solid phase ELISA. Results. Found a trend that confirms the loss of sensitivity to hormones at the stage of malignancy of the endometrium and can be used as diagnostic determinants in determining the nature of intrauterine pathology and criterion of the effectiveness of conservative therapy. Conclusion. Improving etiopatogenetice approach to the therapy of hyperplastic proce.sses of endometrium with determination of receptor phenotype of the endometrium is a research direction in modern gynecology, which will help to improve the results of treatment and prevention of intrauterine pathology. Key words: endometrial hyperplasia,the receptors for progesterone and estrogen, immunohistochemical method.

Calculating the aerodynamics of vertical axis wind turbines

2012 ◽  
Vol 34 (3) ◽  
pp. 169-184 ◽  
Author(s):  
Hoang Thi Bich Ngoc
Keyword(s):  
Wind Turbine ◽  
Incidence Angle ◽  
Vertical Axis ◽  
Rotor Blades ◽  
Vertical Axis Wind Turbine ◽  
Horizontal Axis Wind Turbine ◽  
Velocity Triangle ◽  
Relationship Of ◽  
The Relationship

Vertical axis wind turbine technology has been applied last years, very long after horizontal axis wind turbine technology. Aerodynamic problems of vertical axis wind machines are discussible. An important problem is the determination of the incidence law in the interaction between wind and rotor blades. The focus of the work is to establish equations of the incidence depending on the blade azimuth, and to solve them. From these results, aerodynamic torques and power can be calculated. The incidence angle is a parameter of velocity triangle, and both the factors depend not only on the blade azimuth but also on the ratio of rotational speed and horizontal speed. The built computational program allows theoretically selecting the relationship of geometric parameters of wind turbine in accordance with requirements on power, wind speed and installation conditions.

Tire Treadwear — A Comprehensive Evaluation of the Factors: Generic Type, Aspect Ratio, Tread Pattern, and Tread Composition Part I: Introduction and Details on the Organization of the Program

1986 ◽  
Vol 14 (4) ◽  
pp. 201-218 ◽  
Author(s):  
A. G. Veith
Keyword(s):  
Aspect Ratio ◽  
Comprehensive Evaluation ◽  
Test Method ◽  
Interactive Effects ◽  
Data Analyses ◽  
Main Effect ◽  
Systematic Determination ◽  
Relationship Of ◽  
The Relationship

Abstract This four-part series of papers addresses the problem of systematic determination of the influence of several tire factors on tire treadwear. Both the main effect of each factor and some of their interactive effects are included. The program was also structured to evaluate the influence of some external-to-tire conditions on the relationship of tire factors to treadwear. Part I describes the experimental design used to evaluate the effects on treadwear of generic tire type, aspect ratio, tread pattern (groove or void level), type of pattern (straight rib or block), and tread compound. Construction procedures and precautions used to obtain a valid and functional test method are included. Two guiding principles to be used in the data analyses of Parts II and III are discussed. These are the fractional groove and void concept, to characterize tread pattern geometry, and a demonstration of the equivalence of wear rate for identical compounds on whole tread or multi-section tread tires.

The Awareness Level of the Safety and Health of the Operational Level

2017 ◽  
Vol 3 (1) ◽  
pp. 42
Author(s):  
Roshanira Che Mohd Noor ◽  
Nur Atiqah Rochin Demong
Keyword(s):  
Health And Safety ◽  
Health Conditions ◽  
Effective Strategies ◽  
Operational Level ◽  
Safety And Health ◽  
Health Factors ◽  
The Cost ◽  
The Relationship ◽  
Awareness Level

Providing a safe and healthy workplace is one of the most effective strategies in for holding down the cost of doing construction business. It was a part of the overall management system to facilitate themanagement of the occupational health and safety risk that are associated with the business of the organization. Factors affected the awareness level inclusive of safety and health conditions, dangerous working area, long wait care and services and lack of emergency communication werethe contributed factors to the awareness level for the operational level. Total of 122 incidents happened at Telekom Malaysia Berhad as compared to year 2015 only 86 cases. Thus, the main objective of this study was to determine the relationship between safety and health factors and the awareness level among operational workers.The determination of this research was to increase the awareness level among the operational level workerswho committing to safety and health environment.

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