Large ingot. Main achievements, most important scientific and technical problems, perspective development directions

2017 ◽  
pp. 18-22
Author(s):  
V. S. Dub ◽  
◽  
D. S. Tolstykh ◽  
I. A. Ivanov ◽  
A. N. Malginov ◽  
...  
Author(s):  
R. Beeuwkes ◽  
A. Saubermann ◽  
P. Echlin ◽  
S. Churchill

Fifteen years ago, Hall described clearly the advantages of the thin section approach to biological x-ray microanalysis, and described clearly the ratio method for quantitive analysis in such preparations. In this now classic paper, he also made it clear that the ideal method of sample preparation would involve only freezing and sectioning at low temperature. Subsequently, Hall and his coworkers, as well as others, have applied themselves to the task of direct x-ray microanalysis of frozen sections. To achieve this goal, different methodological approachs have been developed as different groups sought solutions to a common group of technical problems. This report describes some of these problems and indicates the specific approaches and procedures developed by our group in order to overcome them. We acknowledge that the techniques evolved by our group are quite different from earlier approaches to cryomicrotomy and sample handling, hence the title of our paper. However, such departures from tradition have been based upon our attempt to apply basic physical principles to the processes involved. We feel we have demonstrated that such a break with tradition has valuable consequences.


Author(s):  
William H. Massover

Stereoscopic examination of thick sections of fixed and embedded biological tissues by high voltage electron microscopy has been shown to allow direct visualization of three-dimensional fine structure. The present report will consider the occurrence of some new technical problems in specimen preparation and Image interpretation that are not common during lower voltage studies of thin sections.Thick Sectioning and Tissue Coloration - Epon sections of 0.5 μm or more that are cut with glass knives do not have a uniform thickness as Judged by their interference colors; these colors change with time during their flotation on the knife bath, and again when drying onto the specimen support. Quoted thicknesses thus must be considered only as rough estimates unless measured in specific regions by other methods. Chloroform vapors do not always result in good spreading of thick sections; however, they will spread spontaneously to large degrees after resting on the flotation bath for several minutes. Ribbons of thick sections have been almost impossible to obtain.


2014 ◽  
Vol 1 (1) ◽  
pp. 111-114
Author(s):  
Lal Mohan Baral ◽  
Ramzan Muhammad ◽  
Claudiu Vasile Kifor ◽  
Ioan Bondrea

AbstractProblem-based learning as a teaching tool is now used globally in many areas of higher education. It provides an opportunity for students to explore technical problems from a system-level perspective and to be self-directed life-long learner which is mandatory for equipping engineering students with the skill and knowledge. This paper presents a case study illustrating the effectiveness of implemented Problem-based learning (PBL) during five semesters in the undergraduate programs of Textile Engineering in Ahsanullah University of Science and Technology (AUST). An assessment has been done on the basis of feedback from the students as well as their employers by conducting an empirical survey for the evaluation of PBL impact to enhance the student's competencies. The Evaluations indicate that students have achieved remarkable competencies through PBL practices which helped them to be competent in their professional life.


1983 ◽  
Vol 49 ◽  
Author(s):  
M. Van Miegroet

Spontaneous  natural regeneration under variable conditions on sandy soils and continental  sand dunes were analysed in 5 locations in N.E. Belgium.     The number of seedlings varies between 14.000 and 522.000/ha. The most  prominent invading species are red oak, pedunculate oak and Scots pine.    Two principal types of regeneration are recognized : homogeneous groups of  oak or pine and mixtures, predominantly composed by the same species.  Pioneers such as birch, willow, white poplar and wild black cherry do not  play an important role.    Social differentiation sets in quite early and is mainly provoked by age  differences. Therefore early silvicultural intervention is advisable. The  growth relationships between the species indicate that Scots pine is not in  danger of spontaneous elemination by other species. Because of the density  and variability of spontaneous forest regeneration, the conversion of pure  pine stands into mixed forest, using group regeneration to this end, poses no  real technical problems.


2020 ◽  
Vol 15 (4) ◽  
pp. 351-361
Author(s):  
Liwei Huang ◽  
Arkady Shemyakin

Skewed t-copulas recently became popular as a modeling tool of non-linear dependence in statistics. In this paper we consider three different versions of skewed t-copulas introduced by Demarta and McNeill; Smith, Gan and Kohn; and Azzalini and Capitanio. Each of these versions represents a generalization of the symmetric t-copula model, allowing for a different treatment of lower and upper tails. Each of them has certain advantages in mathematical construction, inferential tools and interpretability. Our objective is to apply models based on different types of skewed t-copulas to the same financial and insurance applications. We consider comovements of stock index returns and times-to-failure of related vehicle parts under the warranty period. In both cases the treatment of both lower and upper tails of the joint distributions is of a special importance. Skewed t-copula model performance is compared to the benchmark cases of Gaussian and symmetric Student t-copulas. Instruments of comparison include information criteria, goodness-of-fit and tail dependence. A special attention is paid to methods of estimation of copula parameters. Some technical problems with the implementation of maximum likelihood method and the method of moments suggest the use of Bayesian estimation. We discuss the accuracy and computational efficiency of Bayesian estimation versus MLE. Metropolis-Hastings algorithm with block updates was suggested to deal with the problem of intractability of conditionals.


BMC Nursing ◽  
2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Kim De Groot ◽  
Elisah B. Sneep ◽  
Wolter Paans ◽  
Anneke L. Francke

Abstract Background Patient participation in nursing documentation has several benefits like including patients’ personal wishes in tailor-made care plans and facilitating shared decision-making. However, the rise of electronic health records may not automatically lead to greater patient participation in nursing documentation. This study aims to gain insight into community nurses’ experiences regarding patient participation in electronic nursing documentation, and to explore the challenges nurses face and the strategies they use for dealing with challenges regarding patient participation in electronic nursing documentation. Methods A qualitative descriptive design was used, based on the principles of reflexive thematic analysis. Nineteen community nurses working in home care and using electronic health records were recruited using purposive sampling. Interviews guided by an interview guide were conducted face-to-face or by phone in 2019. The interviews were inductively analysed in an iterative process of data collection–data analysis–more data collection until data saturation was achieved. The steps of thematic analysis were followed, namely familiarization with data, generating initial codes, searching for themes, reviewing themes, defining and naming themes, and reporting. Results Community nurses believed patient participation in nursing documentation has to be tailored to each patient. Actual participation depended on the phase of the nursing process that was being documented and was facilitated by patients’ trust in the accuracy of the documentation. Nurses came across challenges in three domains: those related to electronic health records (i.e. technical problems), to work (e.g. time pressure) and to the patients (e.g. the medical condition). Because of these challenges, nurses frequently did the documentation outside the patient’s home. Nurses still tried to achieve patient participation by verbally discussing patients’ views on the nursing care provided and then documenting those views at a later moment. Conclusions Although community nurses consider patient participation in electronic nursing documentation important, they perceive various challenges relating to electronic health records, work and the patients to realize patient participation. In dealing with these challenges, nurses often fall back on verbal communication about the documentation. These insights can help nurses and policy makers improve electronic health records and develop efficient strategies for improving patient participation in electronic nursing documentation.


Sign in / Sign up

Export Citation Format

Share Document