scholarly journals Determination of destructive forces in a rod-cable arch

Author(s):  
Igor K. Dmitriev

The aim of research - comparison the results of the experimental data with the computer modeling the work of the strengthened brick-cable arch. Methods. Experimental and theoretical methods of research. Results. Firstly, the tests on a small desktop models were performed, for the determination the nature of destruction of the construction. During them, it was discovered, that the arch crash is taking place because of the splitting the small size timber bricks, or as the result of the breaking its steel strengthening elements. Further, the computer model of the construction was created with the help of physically and geometrically nonlinear finite elements at LIRA-SAPR PC. The generated model was load by a concentrated force at its top zone, the same one, as it had been during the experiments before. On the results of the calculation, the maximum deformation was received, which are different from the experimental one on a value less then 10%, what suggests the nearness the computer model to the real construction. The highest compressive strengths of the arch and the largest stretching forces of its steel bands were determined during the further analysis of the model. Maximum splitting and stretching forces also were calculated theoretically, according to the formulas of SP 64.13330.2017 and SP 20.13330.2016. It was determined that the timber bricks have more than 7 times reserve of strength, and the steel bands over them - only times, and during the growth of external force, the arch will crash because of its steel sprengel bands breakage. By the results of the research, the calculation algorithm of such kind constructions was generated, at the base of LIRA-SAPR PC. It was recommended first, to determine deformation of the strengthened brick-cable arch, with further checking the timber elements for splitting and steel sprengel elements for maximum permissible stretching. The problem of stability the flat form of deformation for the brickcable arch are the same as for the glued one, because of the tight connection the timber bricks, with elimination their exit from the frontal plane.

1986 ◽  
Vol 71 ◽  
Author(s):  
I. Suni ◽  
M. Finetti ◽  
K. Grahn

AbstractA computer model based on the finite element method has been applied to evaluate the effect of the parasitic area between contact and diffusion edges on end resistance measurements in four terminal Kelvin resistor structures. The model is then applied to Al/Ti/n+ Si contacts and a value of contact resistivity of Qc = 1.8×10−7.Ωcm2 is derived. For comparison, the use of a self-aligned structure to avoid parasitic effects is presented and the first experimental results obtained on Al/Ti/n+Si and Al/CoSi2/n+Si contacts are shown and discussed.


2014 ◽  
Vol 84 (Supplement 1) ◽  
pp. 25-29 ◽  
Author(s):  
Guangwen Tang

Humans need vitamin A and obtain essential vitamin A by conversion of plant foods rich in provitamin A and/or absorption of preformed vitamin A from foods of animal origin. The determination of the vitamin A value of plant foods rich in provitamin A is important but has challenges. The aim of this paper is to review the progress over last 80 years following the discovery on the conversion of β-carotene to vitamin A and the various techniques including stable isotope technologies that have been developed to determine vitamin A values of plant provitamin A (mainly β-carotene). These include applications from using radioactive β-carotene and vitamin A, depletion-repletion with vitamin A and β-carotene, and measuring postprandial chylomicron fractions after feeding a β-carotene rich diet, to using stable isotopes as tracers to follow the absorption and conversion of plant food provitamin A carotenoids (mainly β-carotene) in humans. These approaches have greatly promoted our understanding of the absorption and conversion of β-carotene to vitamin A. Stable isotope labeled plant foods are useful for determining the overall bioavailability of provitamin A carotenoids from specific foods. Locally obtained plant foods can provide vitamin A and prevent deficiency of vitamin A, a remaining worldwide concern.


1997 ◽  
Vol 36 (04/05) ◽  
pp. 237-240
Author(s):  
P. Hammer ◽  
D. Litvack ◽  
J. P. Saul

Abstract:A computer model of cardiovascular control has been developed based on the response characteristics of cardiovascular control components derived from experiments in animals and humans. Results from the model were compared to those obtained experimentally in humans, and the similarities and differences were used to identify both the strengths and inadequacies of the concepts used to form the model. Findings were confirmatory of some concepts but contrary to some which are firmly held in the literature, indicating that understanding the complexity of cardiovascular control probably requires a combination of experiments and computer models which integrate multiple systems and allow for determination of sufficiency and necessity.


2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Mingming Yang ◽  
Longlong Wang ◽  
Xiaofen Qiao ◽  
Yi Liu ◽  
Yufan Liu ◽  
...  

Abstract The defects into the hexagonal network of a sp2-hybridized carbon atom have been demonstrated to have a significant influence on intrinsic properties of graphene systems. In this paper, we presented a study of temperature-dependent Raman spectra of G peak and D’ band at low temperatures from 78 to 318 K in defective monolayer to few-layer graphene induced by ion C+ bombardment under the determination of vacancy uniformity. Defects lead to the increase of the negative temperature coefficient of G peak, with a value almost identical to that of D’ band. However, the variation of frequency and linewidth of G peak with layer number is contrary to D’ band. It derives from the related electron-phonon interaction in G and D’ phonon in the disorder-induced Raman scattering process. Our results are helpful to understand the mechanism of temperature-dependent phonons in graphene-based materials and provide valuable information on thermal properties of defects for the application of graphene-based devices.


2017 ◽  
Vol 14 (2) ◽  
pp. 55-68 ◽  
Author(s):  
Rita Bužinskienė

AbstractIn accordance with generally accepted accounting standards, most intangibles are not accounted for and not reflected in the traditional financial accounting. For this reason, most companies account intangible assets (IAs) as expenses. In the research, 57 sub-elements of IAs were applied, which are grouped into eight main elements of IAs. The classification of IAs consists in two parts of assets: accounting and non-accounting. This classification can be successfully applied in different branches of enterprises, to expand and supplement the theoretical and practical concepts of the company's financial management. The article proposes to evaluate not only the value of financial information for IAs (accounted) but also the value of non-financial information for IAs (non-accounted), thus revealing the true value of IAs that is available to the companies of Lithuania. It names a value of general IAs. The results of the research confirmed the IA valuation methodology, which allows companies to calculate the fair value of an IA. The obtained extended IAs valuation information may be valuable to both the owners of the company and investors, as this value plays an important practical role in assessing the impact of IAs on the market value of companies.


2020 ◽  
Vol 2 (2) ◽  
pp. 95-106
Author(s):  
Indrawaty Sitepu ◽  
Nurmely Violeta Sitorus

Kangkung hidroponik menjadi kangkung rendang merupakan kegiatan yang dapat meningkatkan nilai tambah, menghasilkan produk yang dapat dikonsumsi, serta menambah pendapatan dan keuntungan produsen.Tujuan penelitian untuk menguraikan apa saja tahapan pengolahan kangkung hidroponik menjadi kangukung rendang, menganalisis biaya produksi, penerimaan, dan pendapatan, menganalisis nilai tambah pengolahan kangkung hidroponik menjadi kangkung rendang, menganalisis apakah usaha pengolahan kangkung hidroponik menjadi kangkung rendang layak diusahakan. Penelitian ini dilakukan di Jalan Bromo lorong Amal Medan Denai Kota Medan. Penentuan daerah penelitian dilakukan secara purposive, Metode pengambilan sampel secara sensus yaitu usaha Syifa Hidroponik dengan pengambilan data ulangan selama 2,5 bualan sebanyak 10 kali ulangan. Hasil penelitian: 1) Tahapan  pengolahan kangkung hidroponik menjadi kangkung rendang yaitu:  Penyediaan bahan baku kangkung hidroponik, kangkung dihaluskan, pengadonan kangkung, telur ayam, tepung beras dan garam, kangkung dikukus, kangkung didinginkan, dipotong-potong, digoreng, pemasakan bumbu rendang, pencampuran kangkung yang digoreng dengan bumbu rendang dan pemasaran. Total biaya pengolahan kangkung hidroponik menjadi kangkung rendang untuk sekali produksi sebesar Rp 545.291,83, penerimaan sebesar Rp 1.500.000,00, per sekali produksi dan pendapatan sebesar Rp 954.708,17 per sekali produksi. Nilai tambah yang dihasilkan dari pengolahan kangkung hidroponik menjadi kangkung rendang tergolong tinggi dengan rasio nilai tambah 75,31% > 50%.Usaha pengolahan kangkung hidroponik menjadi kangkung rendang layak untuk diusahakan dengan nilai R/C rasio 2,75 > 1.  Abstract  Hydroponic water spinach into rendang water spinach is an activity that can increase added value, produce edible products, as well as increase producer income and profits. The purpose of the research is to describe what are the stages of processing hydroponic water spinach into rendang kangukung, analyze production costs, revenue, and income, analyze added value of processing hydroponic water spinach into rendang water spinach, analyzing whether the business of processing hydroponic water spinach into rendang water spinach is worth the effort. This research was conducted in Jalan Bromo Amal Medan Denai alley Medan City. Determination of the study area was done purposively, census sampling method that is Syifa Hydroponic business with retrieval data retrieval for 2.5 boasting as many as 10 replications. The results of the study: 1) The stages of processing hydroponic water spinach into rendang water spinach, namely: Provision of raw materials for hydroponic water spinach, crushed water spinach, stirring water spinach, chicken eggs, rice flour and salt, steamed water spinach, water spinach water spinach, cut into pieces, fried, fried spicy water spinach, cooking water spinach kale, chicken egg, rice flour and salt, steamed water spinach, water spinach kangkung cooled, cut, fried, cooking spices, rendang, mixing fried kale with spicy rendang and marketing. The total cost of processing hydroponic water spinach into rendang water spinach for one production is Rp. 545,291.83, revenue is Rp. 1,500,000.00, per production and income is Rp. 954,708.17 per production. The added value generated from the processing of hydroponic water spinach into rendang water spinach is classified as high with a value added ratio of 75.31%> 50%. The business of processing hydroponic water spinach into rendang water spinach is feasible to be cultivated with an R / C ratio of 2.75> 1.  


2014 ◽  
Vol 3 (4) ◽  
pp. 119 ◽  
Author(s):  
Raffaele Romano ◽  
Nadia Manzo ◽  
Immacolata Montefusco ◽  
Annalisa Romano ◽  
Antonello Santini

<p>In this study the use of liquid carbon dioxide, CO<sub>2</sub>, for extraction of oil from olive paste (<em>Peranzana cultivar</em>)<strong> </strong>were examined and extracted oil was compared with oils obtained by centrifugation, pressure and use of chemical solvent.</p> <p>It is well known that the use of CO<sub>2</sub> has many advantages: miscibility with a wide range of molecules, food safety, non-flammability, absence of residues in the extract, possibility of total solvent recovery and no production of olive mill waste water that are highly polluting for the environment and require expansive disposal.</p> <p>Samples were subjected to the following analyses: determination of Free Fatty Acids (FFA), Peroxides Value (PV), Spectrophotometric Indices, Fatty Acids Composition (FA), determination of biophenols content and determination of Volatile Organic Compounds (VOCs). All samples showed FFA, PV and ?K values within the limits established by law for extra-virgin olive oil. The use of CO<sub>2</sub> did not catalyze hydrolysis, oxidation and condensation of double bonds. Centrifuged oils and oils extracted with carbon dioxide presented the lowest PV and FFA values. Extraction with liquid carbon dioxide contributed to an increasing of phenolic content with a value of 270.5 mg/kg, a value twice that of the oils extracted with centrifugation (135.3 mg/kg) or pressure methods (173.2 mg/kg). Oil extracted with liquid carbon dioxide showed the greatest amount of t-2-octenal and t-2-heptenal, giving herbaceous and pungent notes. Moreover the presence of aromatic compounds such as limonene, generally absent in olive oils, was only detected in the sample extracted with liquid carbon dioxide.</p>


2016 ◽  
Vol 22 (4) ◽  
pp. 573-583 ◽  
Author(s):  
Jerzy GAŁAJ ◽  
Marek KONECKI ◽  
Ritoldas ŠUKYS

The article presents a computer model of the fire extinguishing process using mist nozzles. A previously developed hybrid fire model was used for this purpose. Assumptions and relationships were given to represent a math­ematical model of extinguishing process, which comprises a unique approach to the determination of sprinkling area in an elementary cell of field fire model. A description of simulation tests of the model was given for several different input data, differing by mean diameters of droplets. This enabled a study of their effects on such output parameters as received heat flux, temperature and rate of its growth. For one selected computational cell located on the axis of the nozzle at floor level having the coordinates [10, 10, 1], the obtained results were presented in the form of heat flux and temperature. To simplify the analysis, characteristic parameters of particular curves were listed in the table. Conclusions formulated on the basis of results obtained during tests were specified at the end of work. They confirmed the expected regularity assuming that the extinguishing process was more effective in the case of droplets of a smaller diameter and greater sprinkling intensity. This allows assessing the degree, to which these stream parameters affect the extinguishing effectiveness.


2014 ◽  
Vol 627 ◽  
pp. 45-48
Author(s):  
Cristian Sorin Nes ◽  
Angelica Enkelhardt ◽  
Lucian Bogdan ◽  
Nicolae Faur

Objectives: This paper presents a numerical fatigue life assessment of a self-expandable Nitinol stent. The analysis was performed using the ANSYS 11 software. Methods: Stent durability is an issue which must be addressed during the design of implants. Given the corrosive properties of blood and the cyclic loads that are applied on the stent (the cyclic variation of blood pressure), the determination of fracture parameters and fatigue characteristics of the implant is highly recommended. Breaking of the stent’s wire is particularly dangerous because it can cause the dislocation of a piece of stenotic plaque, which in turn can block a smaller artery, causing a heart attack. On the other hand, any discontinuity in stent structure acts as an accumulating place for stenosis particles, significantly shortening the life of the implant. The stent consists of a cylindrical tube 22.42 mm long, with a diameter of 8.3 millimeters. The wire section is square, 0.2x0.2 millimeters. The stent is only subjected to the pressure generated by the stenoted arterial wall. This evenly distributed pressure is defined at the outer surface of the stent and has a value of 2.5 MPa, corresponding to a 56% blood vessel stenosis. This way, the most severe loading conditions for the stent could be simulated. The stress distribution was then used to asses the fatigue life of the stent. Results and conclusions: The results showed that, in normal conditions (with the maximal internal pressure of 139 mm Hg = 18533 Pa), no damage appears on the stent after 107 cycles.


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