Towards Optimal Designing of thin elastic Plates with a specific free Oscillations Frequency

Thin elastic plates are the basic constructional elements and are very often subjected to dynamic effects especially in the machine-building structures. Their saving design of resonance conditions of operation is an extremely complicated task which cannot be solved analytically. In the present report an efficient and sufficiently general method for optimal design of thin plates is worked out on the basis of energy resonance method of Wilder, the method of the finite elements for dynamic research and the methods of parameter optimization. By means of these methods various limitations and requirements put by the designer to the plates can be taken into account. A programme module for numerical investigation of the weight variation of the plate depending on the taken variable of the designed thickness at different supporting conditions is developed. The reasons for the considerable quantity and quality difference between the obtained optimal designs are also analysed

Volumes of Compact Manifolds

We present a systematic calculation of the volumes of compact manifolds which appear in physics: spheres, projective spaces, group manifolds and generalized flag manifolds. In each case we state what we believe is the most natural scale or normalization of the manifold, that is, the generalization of the unit radius condition for spheres. For this aim we first describe the manifold with some parameters, set up a metric, which induces a volume element, and perform the integration for the adequate range of the parameters; in most cases our manifolds will be either spheres or (twisted) products of spheres, or quotients of spheres (homogeneous spaces). Our results should be useful in several physical instances, as instanton calculations, propagators in curved spaces, sigma models, geometric scattering in homogeneous manifolds, density matrices for entangled states, etc. Some flag manifolds have also appeared recently as exceptional holonomy manifolds; the volumes of compact Einstein manifolds appear in String theory.Comment: 26 pages, no figures; updated addresses and bibliography. To be published in Rep. Math. Phy

SOME AGE PECULIARITIES OF THE WALL STRUCTURE OF ILIAC ARTERIES

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ADENOSINE TRIPHOSPHATASE ACTIVITY OF THE VENOUS WALL IN CAT

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Study of influence of heat stress on some physiological and productive traits in Holstein-Friesian dairy cows

Received: October 6th, 2020 ; Accepted: February 1st, 2021 ; Published: March 18th, 2021 ; Correspondence: [email protected] aim of the research was to study the effect of heat stress (HS) on some physiological and productive traits in Holstein-Friesian dairy cows. The study included 22 cows on different parities. In the building where the cows were housed, the temperature-humidity index (THI) was reported at 10:00 and 15:00 h, at the same time the rectal temperature (RT) and respiratory rate (RR) were reported for each of the examined cows. The daily rumen activity was taken from the SCR system by Allflex. The average THI values in May were 71, in June - 75, in July - 74, and in August - 77, from which it follows that in the summer months the cows were in conditions of mild to moderate heat stress throughout the day. The average daily milk yield of the cows increased from May to June and reached 41.44 kg day-1 , then decreased in July and August to 37.2 and 32.48 kg day-1 , respectively. With an increase in the THI values, an increase in the RR and RT was registered, as in THI above 79 the RR was 56.54 per min, and the RT was 39.33 °C. With increasing the THI values, the rumination of the cows decreased from 563 per day at THI < 72 to 542.5 at THI > 79. In cows with high daily milk yield, a higher RT was registered, and in cows with more than 50 kg per day, the RT was 39.09 °С. A more intense rumination was found in cows with higher daily milk yield. In cows with an average daily milk yield of 33.26 kg, an average of 450 ruminations per day were reported, and in those with an average milk yield of up to 42.89 kg - 650 ruminations per day. From the research conducted it was found that the studied physiological traits - rectal temperature, respiration rate and rumination are influenced by HS and the intensity of this effect depend on the daily milk yield of cows and THI levels

Exchange of Higher Education Teaching and Learning Practices Between UK and Thailand: A Case Study of RailExchange Courses

The RailExchange project has been developed in collaboration between two universities, one UK-based and one Thailand-based, to work on educational ideas for rail to benefit the rail industry in Thailand. At the same time, a new rail Master programme has been designed with a strong input from the rail industry in terms of technical and interpersonal skills necessary for a formation of a successful rail graduate. The new programme has been established at the Thai university and aligned with Thai and international higher education frameworks (AUN-QA and TQF). As part of the activities listed in the exchange project, the lecturers from the UK have been invited to conduct short experimental classes to teach on three different subjects, which are part of the new rail Master’s curriculum. The paper presents feedback received from participants of the three courses in terms of learning activities, academic activities and personal experience. The analyses of the feedback reveal that the UK visiting lecturers helped in broadening the perspective of the Thai academics and students in terms of educational content and active learning style, such as a hands-on approach and applied learning style with real-life scenarios and student-led learning. The English language was used to deliver the experimental classes to Thai participants, who represented academia and industry, and for majority of the participants, it was not a barrier in actively participating in a course. Feedback received highlighted differences between the UK and Thai approaches to higher education learning, but also suggested improvements, listed in recommendations, which should be taken into account in the delivery of the Master programme in rail in the near future

CUSTOMER RELATIONSHIPS AND BRAND EQUITY IN CHINA'S BANKING SERVICES

Despite tremendous interest in brand equity and relationship marketing, little conceptual development has addressed whether relationships exist between these important marketing issues. Based on existing frameworks (customer-based brand equity and relationship marketing), this paper forwards customer relationships as a branding-related initiative critical to creation of brand equity. This paper presents exploratory research to develop an initial understanding of the constructs of customer relationships, the dimensions of brand equity and the associations between them. The data illustrate that both consumers and providers in Chinese banking services sector perceive that brand equity can be influenced by customer relationships. A conceptual framework and a number of hypotheses for further study are propose

Relation between first lactation milk yield and functional traits in dairy cows

The aim of the study was to analyze the relationship between first lactation milk yield (FLMY) and age at first calving (AFC), longevity and productive life in dairy cows. The study covered 944 Holstein cows housed in 5 dairy cattle farms in Bulgaria. All cows from the five farms culled in the period 2012–2018 with FLMY data were included. The average AFC for all culled cows included in the study was relatively high for the Holstein-Friesian breed - 29.75 months. The average FLMY of the herds included in the study was 7,660.94 kg with significant herd variation from 5,899.09 kg to 8,646.0 kg. Significant effect of the herd (P < 0.001), AFC and the associated effect of the herd and AFC (P < 0.05) on the average FLMY were found. The highest FLMY was reported in primiparous with AFC of 28–30 months – 7,860.8 kg, and the lowest in those with AFC ≤ 24 months – 7322.8 kg. In the herd with the lowest average FLMY - 5,899.09 kg 27.5% of the heifers had calved at age over 34 months. A statistically significant effect of AFC (P < 0.001) was found on longevity, whereas the productive life was significantly influenced by FLMY (P < 0.05). A tendency for higher longevity for cows with higher AFC of 34–37 months and over 37 months – 5.9 and 5.8 years, respectively was observed. The lowest were the longevity values for cows calved at age up to 24 months – 4.9 years. The cows with the lowest average FLMY (up to 4,000 kg) had the shortest productive. Both very low and high AFC were associated with lower first lactation cow productivity and shorter productive life. The losses for farmers were greater when keeping a high AFC in heifers, which increases the cost for housing them, and the lower productivity and longer productive life reduce the probability

Postoperative Cardiac Complications in Patients Undergoing Laryngectomies

Introduction: The European Society of Cardiology provides guidelines for preoperative cardiac risk assessment in patients undergoing laryngectomies. Cardiovascular risk factors: chronic congestive heart failure, ischemic heart disease, severe arrhythmias, have important prognostic significance for major surgical interventions and must be carefully evaluated preoperatively.The Aim of the study is to determine the most common postoperative cardiac complications in patients undergoing laryngectomies.Materials and Methods: A clinical prospective cohort study including 120 patients undergoing total laryngectomy, in the Department of Otorhinolaryngology at the University Hospital „Queen Giovanna“ – ISUL, Sofia, 2014-2017.Results and discussion: The most common postoperative cardiac complications in patients undergoing laryngectomies are arterial hypertension, angina pectoris, and tachycardia.Conclusion: There are many cardiac risk factors in patients undergoing laryngectomies that can lead to postoperative complications, respectively prolong the hospital stay and increase medical expenses