Vertical stiffeners and internal pressure - influencing factors on distribution of meridional stresses in steel silos on discrete supports

Steel silos are interesting, complicated facilities. In order to ensure unloading of whole amount of stored product by gravity, they are often placed on supporting structure. Values of stresses in joints between thin sheets and supporting frame elements are very high, which could cause local loss of stability in thin shells. Many researchers have worked on values and distribution of the meridional stresses in that joints. Their traditional approach is to divide in their minds cylindrical shell on two parts - discretely supported ring beam and continuously supported shell above it. As a result of their efforts critical height of shell Hcr and ideal position of intermediate stiffening ring on shell are determined. The scientific results are based on semi-membrane theory of Vlasov, in which influence of vertical stiffeners and internal pressure is not accounted. On other hand all steel silos are loaded with an internal pressure and majority of them have vertical stiffeners above supports. Is it possible the obtained scientific results to be applied to these silos? In a present article the author will show that stiffeners and pressure should not be ignored in an analysis

Arch effect in silos on discrete supports - Is it a myth or reality?

Steel silos are interesting, complicated facilities. In order to assure its complete emptying by gravity they are often placed on supporting frame structure above the ground. Values of stresses in joints between thin walled shell and supporting frame elements are very high. It can cause the local buckling in the shell. The simplest way to design steel silos is to divide hypothetically the cylindrical shell into two parts - ring beam, supported in some points and shell above, uniformly supported. This conception is accepted by European Standard EN 1993-4-1. The particular moment is that the ring beam and cylindrical body above it are separated. Actually the two elements are jointed and work together in the same time. Considering the last results of Zeybek, Topkaya and Rotter from 2019, and as well as his own research, the author asks the question if it is true that the transferring of discrete base reactions to the cylindrical body is done by bending work of the ring beam, which is the conception in EN 1993-4-1? Or the vertical reaction forces are actually redistributed on the height based on the work of the cylindrical shell under compression as an arch. Using the contemporary capabilities of the programs for spatial analysis of building structures the author will try to find the answer of this question

Bilateral Simultaneous Retrobulbar Neuritis After Swine Flu: A Clinical Case Report

Retrobulbar neuritis is most commonly demyelinating and associated with multiple sclerosis. Rarely, it has been associated with viral and bacterial infections, systemic autoimmune diseases, vaccinations, and certain medications. We present a case of bilateral simultaneous optic neuritis following swine flu. We did a case report on a 56-year-old male patient with retrobulbar neuritis after swine flu, who had been treated in Alexandrovska Hospital, Sofia, Bulgaria. The diagnosis was based on the clinical exam, clinical course and on specialized investigations. The follow-up period was from February 2015 until April 2021. On admission in the hospital the best-corrected visual acuity of both eyes was decreased – VOD=0.6, VOS=PPLC. 30-2 visual field testing demonstrated no light sensitivity in the left eye, and decreased – in the right. Therapy was begun with methylprednisolone, pentoxiphylline, vinpocetine, piracetam, and clopidogrel. On day 19 the visual fields were significantly improved. On discharge, BCVA was 0.6-0.7 of the right eye and 0.7-0.8 – of the left, and improved to 1.0 during the follow-up period. Bilateral simultaneous retrobulbar neuritis is an infrequent immune complication after swine flu. In our case, we achieved recovery of normal visual acuity and a significant improvement in the visual fieds of both eyes. Therapy included systemic corticosteroids, pentoxiphylline, vinpocetine, piracetam, and clopidogrel

Ocular manifestations of diabetes mellitus: a general overview

Introduction: Diabetes is on the rise – according to the World Health Organization (WHO) over 400 million people worldwide are affected. Elevated blood sugar levels pose a risk for the lives of these patients as well as a serious deterioration in their quality of life. Apart from diabetic retinopathy, which poses an immediate risk to vision, virtually any part of the visual-sensory system can be irreversibly damaged. The objective of the study is to evaluate the prevalence of different eye complications in patients with type two diabetes and to propose guidelines for early diagnosis, clinical evaluation and treatment.Contingent and Methods: A total of 1654 adult patients hospitalized at the Clinic of Ophthalmology in the Alexandrovska Hospital were clinically evaluated including OCT scanning and visual field testing. Results: Approximately 13% of the patients (212) had type two diabetes as a concomitant disease. The most common eye manifestation of diabetes was cataract found in 73% of the patients. Other ocular manifestations of diabetes included primary open-angle glaucoma (POAG), secondary glaucoma, retinopathy and vitreal bleeding, retinal detachment, ischemic optic neuropathy, oculomotor dysfunction and eye-lid inflammation.Conclusion: Diabetes mellitus bears a significant risk for ocular complications and visual disability. The disease can affect any part of the visual system ‒ the sensory, the oculomotor and the adjacent tissues (eyelids and tear production and outflow). Patients with diabetes require regular follow up and timely intervention to prevent irreversible damage to the visual system

Mean Age of Patients with and without Type 2 Diabetes Mellitus during Surgical Treatment of Age-Related Cataract

Introduction: Age-related cataract is one of the most common causes of preventable blindness. Type 2 diabetes is a non-infectious epidemic disease with an ever-increasing number of diseased patients. Cataract is one of the leading causes of reduced vision in diabetics. The preferred treatment method is phacoemulsification. The aim of the present study was to compare the mean age of patients with and without diabetes type 2 at the time of cataract surgery. Materials and methods: After informed consent and approval by the Ethics Commission of the Medical University of Sofia, 176 patients admitted to the Clinic of Ophthalmology at the University Hospital „Alexandrovska“ for surgical treatment of cataract were randomized. Inclusion criteria: diagnosed age-related cataract, requiring surgical treatment. Patients were divided into two groups – diabetic type 2 and non-diabetic patients. Inclusion criteria for the group of diabetics: medical history of diabetes type 2 and administration of anti diabetic medications. Results: The average age of patients undergoing cataract surgery was 70.81 years. The average ageof patients with diabetes type 2 was 65.89 years, and that of non-diabetics – 71.74 years. Diabetes type 2 was established at 15.91 % of patients (19 men and 9 women). Conclusion: Patients with diabetes type 2 develop age-related cataract, requiring surgical treatment, at an earlier age compared to non-diabetics. The transparency of the lens in diabetic patients is of particular importance for the diagnosis and treatment of the diabetic retinopathy. Follow-up by an ophthalmologist and maintenance of strict blood glucose control are necessary to reduce the incidence of vision loss, caused by cataract and diabetic retinopathy

Memory Effect and Triplet Pairing Generation in the Superconducting Exchange Biased Co/CoOx/Cu41Ni59/Nb/Cu41Ni59 Layered Heterostructure

We fabricated a nanolayered hybrid superconductor-ferromagnet spin-valve structure, the resistive state of which depends on the preceding magnetic field polarity. The effect is based on a strong exchange bias (about -2 kOe) on a diluted ferromagnetic copper-nickel alloy and generation of a long range odd in frequency triplet pairing component. The difference of high and low resistance states at zero magnetic field is 90% of the normal state resistance for a transport current of 250 {\mu}A and still around 42% for 10 {\mu}A. Both logic states of the structure do not require biasing fields or currents in the idle mode.Comment: 9 pages, 4 figures, Accepted to Applied Physics Letter