Simulation of the Chemical Influences to the Polishing Process of Optical Glasses

2008 ◽  
Vol 39-40 ◽  
pp. 293-298
Author(s):  
Elisabeth Becker ◽  
Andreas Prange ◽  
Reinhard Conradt

In the last step of fabrication, optical and fine-optical glasses are polished to fulfill the optical requirements for their surfaces. The major influences on the process are caused by the mechanics of the polishing machine, by the chemistry (composition of the glass, as well as the polishing suspension of water and polishing grains, CeO2) [1], [2] and by the material and structure of the polishing pad. From previous own results [3], [4] it is known that the stability of the colloidal system has a major impact on the polishing results and that it is influenced by matter from the glass removal. Thus the glasses have been classified in glass families, depending on their chemical composition and their mutual compatibility in the process. As it is not always possible to measure this compatibility, the impact of the various dissolved glass ions in the fluid phase of the polishing suspension is simulated by the use of thermodynamic parameters. Therefore the specific solubility products in the aqueous phase are modeled (using, e.g., the software HSC) comprising steady accumulation of ions from the glass removal. With this simulation, the examination of the chemical part of the chemo-mechanical polishing process will be concluded.


2019 ◽  
Vol 34 (3-4) ◽  
pp. 145-156
Author(s):  
Bogdan Nikolic ◽  
Hadi Waisi ◽  
Sanja Djurovic ◽  
Milos Dugalic ◽  
Vladan Jovanovic

We surveyed different aspects of the application of agrochemicals (pesticides and foliar non-standard fertilizers) on the nutritive value and other non-yield characteristics of crop plants. The survey was based on results of our own trials and studies conducted by other researchers. Various parameters of plant and seedling growth, and yield, were analyzed, as well as the chemical composition, and energetic and thermodynamic parameters of plants in order to better assess the impact of these agrochemicals on crops. The application of various agrochemicals has been found to affect the germination of seeds produced by treated plants. The most significant and most diverse results have been obtained by analyzing the yield and yield components of many different crops (field crops, fruits, vegetables), as well as their chemical composition (mineral elements, different sugars, secondary metabolites, etc.) in terms of improving their nutritive quality. It was found that in maize seedlings it occurs by changing the content of various elements, as well as polyphenol profiles and thermodynamic parameters, and the effects did not only depend on the dosage of agrochemicals but also on maize genotype. We also found that agrochemicals affected the energetic and thermodynamic parameters of individual maize plants, as well as the parameters of plant growth and yield. It was noticed that these agrochemicals greatly affected the content of microelements, starch and crude proteins in maize and barley, sugar and polyphenol contents in various fruit trees and soybean. We noted that in certain agroecological situations these agrochemicals have led to spectacular magnification of yields of different crops, but there were also situations when they did not have any positive effect on crop yield, which is discussed also in the context of results of other researchers.



2010 ◽  
Vol 126-128 ◽  
pp. 64-69
Author(s):  
Wei Li ◽  
Cheng Jin ◽  
Xiao Zhen Hu

How to achieve the precision double-sided polishing process is a important issue for wafer manufacturing, it depends on machining condition such as machining environment, polishing speed, polishing operation mode, polishing pressure, polishing fluid etc. The key factor to the wafer surface quality is the stability of the polishing pressure. This paper analyzes the impact of double-sided polishing pressure in polishing process, using AMESim software to simulate the pressure standard deviation’s changes under diffrent polishing pressures, and carries out some experiments to identify the impact of polishing parameters (such as the ring gear ratio, polishing speed, polishing pressure) to the polishing pressure stability and the wafer surface quality.



2020 ◽  
Vol 24 (2) ◽  
pp. 4-9 ◽  
Author(s):  
I.I. Shepelev ◽  
A.M. Nemerov ◽  
E.N. Eskova ◽  
E.I. Zhukov ◽  
A.Yu. Sochaczew ◽  
...  

To reduce the impact of alumina sludge storage on the environment, a number of environmental technical solutions have been tested and implemented. Laying a polymeric film on a bed slurry maps and the construction of artificial water level decrease led to the absence of anthropogenic interference, and created favorable conditions for ensuring the stability of the ecological system in the area adjacent to the sludge storage. After the implementation of the environmental events area negative impact of sludge decreased to 150–200 m from the contour of the slurry of the map, outside this zone there are qualitative changes in the chemical composition of groundwater, the alkaline reaction of the environment decreases less than 8.0 units, chemical composition of groundwater is virtually the same background.



2015 ◽  
Vol 231 ◽  
pp. 125-131
Author(s):  
Edyta Rożniata ◽  
Dariusz Zasada

The results of a microstructure, energy dispersive X-ray spectroscopy (EDS) analysis and hardness investigations of the hypoeutectoid steels with 1% Ni, imitating by its chemical composition toughening steels, are presented in the paper. According to PN-EN 10027 standard this steel should have a symbol 37NiMo4-3.The kinetic of phase transformation of undercooled austenite of investigated steel was presented on CCT diagram (continuous cooling transformation). The CCT diagram of tested steel is characterized in that the curves of beginning of the diffusion transitions form a letter "C" and are not separated from bainitic transformation by the stability range of the undercooled austenite.The EDS analysis performed for the selected cooling rates did not reveal any changes in the distribution of alloying elements of hypoeutectoid 37NiMo4-3 steel. However, these studies, from the point of view of the effect of alloying elements (acting jointly) are only the preliminary assessment analysis (beginning) of the impact of the chemical composition gradient in micro-scale in iron-based alloys.



Author(s):  
Robert J. Carroll ◽  
Marvin P. Thompson ◽  
Harold M. Farrell

Milk is an unusually stable colloidal system; the stability of this system is due primarily to the formation of micelles by the major milk proteins, the caseins. Numerous models for the structure of casein micelles have been proposed; these models have been formulated on the basis of in vitro studies. Synthetic casein micelles (i.e., those formed by mixing the purified αsl- and k-caseins with Ca2+ in appropriate ratios) are dissimilar to those from freshly-drawn milks in (i) size distribution, (ii) ratio of Ca/P, and (iii) solvation (g. water/g. protein). Evidently, in vivo organization of the caseins into the micellar form occurs in-a manner which is not identical to the in vitro mode of formation.



1997 ◽  
Vol 77 (03) ◽  
pp. 504-509 ◽  
Author(s):  
Sarah L Booth ◽  
Jacqueline M Charnley ◽  
James A Sadowski ◽  
Edward Saltzman ◽  
Edwin G Bovill ◽  
...  

SummaryCase reports cited in Medline or Biological Abstracts (1966-1996) were reviewed to evaluate the impact of vitamin K1 dietary intake on the stability of anticoagulant control in patients using coumarin derivatives. Reported nutrient-drug interactions cannot always be explained by the vitamin K1 content of the food items. However, metabolic data indicate that a consistent dietary intake of vitamin K is important to attain a daily equilibrium in vitamin K status. We report a diet that provides a stable intake of vitamin K1, equivalent to the current U.S. Recommended Dietary Allowance, using food composition data derived from high-performance liquid chromatography. Inconsistencies in the published literature indicate that prospective clinical studies should be undertaken to clarify the putative dietary vitamin K1-coumarin interaction. The dietary guidelines reported here may be used in such studies.



Author(s):  
Olena Pikaliuk ◽  
◽  
Dmitry Kovalenko ◽  

One of the main criteria for economic development is the size of the public debt and its dynamics. The article considers the impact of public debt on the financial security of Ukraine. The views of scientists on the essence of public debt and financial security of the state are substantiated. An analysis of the dynamics and structure of public debt of Ukraine for 2014-2019. It is proved that one of the main criteria for economic development is the size of public debt and its dynamics. State budget deficit, attracting and using loans to cover it have led to the formation and significant growth of public debt in Ukraine. The volume of public debt indicates an increase in the debt security of the state, which is a component of financial security. Therefore, the issue of the impact of public debt on the financial security of Ukraine is becoming increasingly relevant. The constant growth and large amounts of debt make it necessary to study it, which will have a positive impact on economic processes that will ensure the stability of the financial system and enhance its security.



2018 ◽  
Vol 69 (4) ◽  
pp. 961-964
Author(s):  
Andrei Vasile Olteanu ◽  
Georgiana Emmanuela Gilca Blanariu ◽  
Gheorghe Gh. Balan ◽  
Dana Elena Mitrica ◽  
Elena Gologan ◽  
...  

Non-alcoholic fatty liver disease (NAFLD) has become of major interest worldwide, it is estimated that more than 20% of the general population suffer from liver steatosis. NAFLD is highly associated with metabolic risk factors like type 2 diabetes mellitus, obesity and dyslipidemia, the patients diagnosed with NAFLD should adopt a high fiber low calorie diet, with reduced saturated fat and carbohydrates content, leading to weight loss and improvement of metabolic profile. Our study is aiming to shape the profile of the patient interested in being informed related to food quality and chemical composition and to evaluate the aspects on the food products label which are important for the customer. Between June 2017 and December 2017, 83 patients diagnosed with NASH were included in the study, representing the study group, while 33 subjects, without metabolic syndrome or digestive diseases, selected from patient list belonging to two general practitioners, constituted the control group. Related to the interest of being informed about the chemical composition and nutritional value of the products bought, the study showed a low interest for the provided information on nutritional value. lack of confidence in the provided information and complexity of the information are understandable, the high number of subject reasoning through lack of immediate clinical benefit is surprising. Among the healthy population the willingness to pay attention to this aspect is extremely low.



2018 ◽  
Vol 35 (4) ◽  
pp. 133-136
Author(s):  
R. N. Ibragimov

The article examines the impact of internal and external risks on the stability of the financial system of the Altai Territory. Classification of internal and external risks of decline, affecting the sustainable development of the financial system, is presented. A risk management strategy is proposed that will allow monitoring of risks, thereby these measures will help reduce the loss of financial stability and ensure the long-term development of the economy of the region.



1985 ◽  
Vol 17 (9) ◽  
pp. 1-12 ◽  
Author(s):  
Carl G. Enfield

Relatively immobile chemicals have been observed moving significantly faster than anticipated from hydrophobic theory. A theory is developed considering transport in three mobile fluid phases which can be used to describe this facilitated transport. The convective dispersive transport equation is solved utilizing a transformation of variables which permits utilizing existing solutions covering a wide variety of boundary conditions. The impact of the facilitated transport is demonstrated for one case where the soils organic carbon is 10%. If 2% of the fluid phase is an organic fraction, the theory developed projects that hydrophobic theory may underestimate mobility by more than 100 times. At concentrations of dissolved organic carbon normally observed in nature (5 - 10 mg/l), a measurable increased mobility is anticipated for the very immobile compounds like dioxins.



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