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1
Xiong, Li Li, and Jian Hua Wei. "Research on Shear Properties of Top Story T-Joints in R.C. Frame Structure with Special-Shaped Columns under Low Cyclic Reversals." Advanced Materials Research 368-373 (October 2011): 452–55. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.452.
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On the basis of five prototype top storey T-joints in R.C. frame structure with special-shaped columns, this paper examines shearing characteristic and mechanism. Based on the theory of softened strut-tie, the formulas for shearing strength of top story exterior joints in R.C. frame structure with special-shaped columns are derived. Three calculations are given in this paper, which are theoretical calculation, technical specification calculation and experimental value. The theoretical calculating value is compared with the testing results and the analysis shows that the technical specification formula can ensure high safety.
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Han, Jin Sheng, Xue Wen Wang, Li Yi Wang, and Min Ji. "Comparison and Analysis of the Calculation Formulas for the Bearing Capacity of Concrete Filled Steel Tubular Columns." Advanced Materials Research 1065-1069 (December 2014): 1337–40. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.1337.
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At present, many analysis methods and calculation formulas of the bearing capacity of concrete filled steel tubular columns have been researched. But these numerous calculation formulas of the bearing capacity have varied forms, and the application scope and the calculation precision of them are also quite different, which makes it difficult and confused for engineering designer to choose a suitable formula. Primary calculation formulas of the bearing capacity of concrete filled steel tubular columns are summarized. The calculation results of these formulas are compared with some test results of the concrete filled steel tubular columns with a large diameter. The applicability and the accuracy of these formulas are analyzed. Based on these comparisons and analyses, reasonable suggestion is given to select the suitable formula. Finally, one formula is provided to calculate the ultimate bearing capacity of concrete filled steel tubular columns reinforced with steel bars.
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Stauskis, Vytautas J. "THE EFFECT OF LOCATION OF SOUND-ABSORBING MATERIALS IN CALCULATING THE REVERBERATION TIME OF THE HALL BY DIFFERENT FORMULAS." JOURNAL OF CIVIL ENGINEERING AND MANAGEMENT 9, no. 2 (June 30, 2003): 83–87. http://dx.doi.org/10.3846/13923730.2003.10531308.
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Earlier formulas used for calculating the echoing length in a hall did not make allowance for the location of sound-absorbing materials and the shape of the hall. Fitzroy in 1959 and Neubauer in 1999 tried to take these factors into account. The echoing length calculations were made in a 1018 m3 hall where sound-absorbing materials were placed on the floor and the lateral walls. Formulas produced by 6 authors were used for calculations. As the echoing length is calculated by Fitzroy's and Neubauer's formulas, with the sound-absorbing materials of different acoustical properties placed on various planes of the hall, large differences in values are obtained compared with the calculations based on Eyring's formula. When a half of the floor area is covered with a sound-absorbing material, the increase of its absorption ratio results in the increase of the difference in echoing lengths calculated by Fitzroys' and Neubauer's formulas. When only the lateral walls are covered with sound-absorbing material, the increase of their absorption coefficient from 0,1 to 0,6 results in a 3 s (or three-fold) increase in the echoing length difference when calculated by Fitzroy's formula and in a 2 s (or two-fold) increase when calculated by Eyring's formula. Calculation by other formulas gives an insignificant difference of ∼ 0,5 s. As Fitzroy's and Neubauer's formulas are used, the difference becomes more significant: the larger the average hall absorption coefficient, the larger the difference.
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Camps, Vicente J., Ramy R. Fikry Riad, Esteban Caravaca-Arens, Fady E. Labib, Veronica Mateo, María T. Caballero, and David P. Piñero. "Comparison of Four Intraocular Power Calculation Formulas in Keratoconus Eyes." Open Ophthalmology Journal 15, no. 1 (July 7, 2021): 96–102. http://dx.doi.org/10.2174/1874364102115010096.
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Introduction: This study aimed to evaluate the differences in Intraocular Lens (IOL) power in keratoconus (KC) eyes between calculations obtained clinically with the most commonly used formulas in healthy eyes (SRK T, Holladay 1, Hoffer Q and Haigis) as well as to define predictive factors for such differences. Methods: This retrospective study comprised 43 keratoconus eyes of 22 patients with no previous ocular surgery. IOL powers were calculated with SRK T, Holladay 1, Hoffer Q, and Haigis formulas, considering the Effective Lens Position (ELP) of each formula and the desired refraction of 0 D (Rdes=0 D). Results: All differences between formulas were statistically significant and clinically relevant. Haigis formula always provided higher values compared to the rest of the formulas, with the highest differences observed when comparing Haigis with Hoffer (0.84 D) and Hoffer Q (1.17 D) formulas. The lowest difference was obtained for the comparison between SRK-T and Holladay 1 formulas (0.22 D). Differences of the Haigis formula compared to the rest were higher as the magnitude of the IOL power calculated decreased, becoming the patient more myopic. Increased differences between Haigis and Hoffer formulas were observed in eyes with deep anterior chambers, steeper anterior and posterior corneal surfaces, and high axial lengths. Conclusion: The most comparable results in IOL power in keratoconus are provided by the Holladay 1 and SRK T formulas, whereas the Haigis formula provides the most discrepant outcome. The consideration of the curvature of the second corneal surface in IOL power calculations in keratoconus may decrease the variability between calculation methods. However, other factors as anterior chamber depth or axial length are also relevant.
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Ildarkhanov, Radik. "The Calculation of the Fuel Cost for a Car." Periodica Polytechnica Transportation Engineering 47, no. 4 (March 12, 2018): 277–82. http://dx.doi.org/10.3311/pptr.10553.
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The proposed formula derived considering the physical phenomena which occur during truck operation makes it possible to calculate fuel cost during the operation more accurately. The results of comparison of calculations by the proposed formula with test results tractors parties “TransEuroTest” are presented. The results of the calculation with the help of new formula differ from the experimentally obtained values of the fuel consumption of vehicles for not more than 1%. The average fuel consumption of tractors at an average speed is shown. The proposed formula for calculating the cost makes it easy to compare the fuel consumption of different vehicle options. The formula can also be used when evaluating the effect of vehicle weight on fuel consumption, which is impossible according to the well-known formulas.
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Konarzewska, Malgorzata, and Artur Konarzewski. "CHOSEN ASPECTS OF DEFINING TECHNICAL WEAR OF BUILDINGS." Technological and Economic Development of Economy 12, no. 3 (September 30, 2006): 200–203. http://dx.doi.org/10.3846/13928619.2006.9637742.
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The article discusses the problem of defining borderline values of technical wear of a building and/or its components. Formulas and methods of defining wear have been highlighted, and an example has been presented, where the calculations were made according to proportionality formulas: Ross and Unger, Romstorfen and Eytelwein. While analysing results, some differences have been pointed out in the assessment of the degree of wear, depending on the time lapse and selection of a calculation formula. Selecting an inappropriate calculation procedure (depending on the focus on an element), and incorrect manner of defining technical life span of an element or a whole building leads to serious errors. The justifiability of the above statement has been proved in the summary, where a comparison of element use, according to different calculation formulas, has been presented in a graphic form.
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Jiang, Shuan, Li Li Bai, and Wei Chen Xue. "Calculation of Crack Width of Steel-Concrete Composite Beams Prestressed with Internal Tendon." Advanced Materials Research 850-851 (December 2013): 183–87. http://dx.doi.org/10.4028/www.scientific.net/amr.850-851.183.
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Steelconcrete composite beam prestressed with internal tendon (SCCPIT) is composed of prestressed concrete slab, steel beam and shear connectors, etc. At present, there is no calculation formula for crack width of SCCPIT in current design codes Eurocode 4, ASSHTO or Chinese Code for Design of Steel Structures (GB 500172003). In this paper, the calculating formulas for crack width provided in Code for Design of SteelConcrete Composite Structure (DL/T 50851999) were adopted as a basis for modification. On the basis of available test results, the calculation formulas for uneven coefficient of reinforcement strain and average crack space were modified by consideration of concrete slab width and combined force ratio. Hence, empirical calculating formulas of crack width of SCCPIT under negative moment were proposed. In order to verify the accuracy of the proposed formulas, five simply supported SCCPITs previously conducted by research group were analyzed, and comparisons indicated that the calculated values are in good agreement with the test results.
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Pershin, К. B., N. F. Pashinova, I. A. Likh, А. Yu Tsygankov, and S. L. Legkikh. "Intraocular Lenses Optic Power Calculation in Extremely Short Eyes." Ophthalmology in Russia 19, no. 1 (April 7, 2022): 91–97. http://dx.doi.org/10.18008/1816-5095-2022-1-91-97.
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Purpose: to choose the optimal formula for calculating the IOL optical power in patients with an axial eye length of less than 20 mm.Patients and methods. A total of 78 patients (118 eyes) were included in the prospective study. Group I included 30 patients (52 eyes) with extremely short eyes (average axial eye length of 19.60 ± 0.42 (18.54–20.00) mm), group II consisted of 48 patients (66 eyes) with a normal axial length 22.75 ± 0.46 (22.00–23.77) mm with implantation of various monofocal IOL models. The average follow-up period was 13 months. IOL optical power was calculated using the SRK / T formula, retrospective comparison — according to the formulas Hoffer-Q, Holladay II, Olsen, Haigis and Barrett Universal II.Results. In group I, the maximum average estimation error was determined for the formula Haigis (0.88 ± 0.35), then for the formula Olsen, Barrett Universal II, Kane, SRK / T, Holladay 2 and Hoffer-Q (0.51 ± 0.12, 0.16 ± 0.38, 0.13 ± 0.28, 0.10 ± 0.59, 0.05 ± 0.54 and –0.12 ± 0.42, respectively). Similar data were obtained for the average absolute error — for the formulas Haigis, Olsen, Barrett Universal II, SRK / T, Holladay 2, Hoffer-Q and Kane, it was 0.85 ± 0.31, 0.78 ± 0.25, 0.21 ± 0.10, 0.79 ± 0.23, 0.73 ± 0.24, 0.19 ± 0.08 and 0.17 ± 0.06, respectively. When comparing the formulas, significant differences were found for the formulas Hoffer-Q, Barrett Universal II and Kane in comparison with the formulas Haigis, Olsen, SRK / T and Holladay II (p < 0.05) in all cases, respectively, which indicates the advantage of these formulas for the group patients with extremely short eyes. In group II, there were no significant differences between the studied formulas (p > 0.05).Conclusion. This paper presents an analysis of our own data on the effectiveness of six formulas for calculating the IOL optical power in extremely short (less than 20 mm) eyes in comparison with the normal axial length. The advantage of the Hoffer-Q, Barrett Universal II and Kane formulas over Haigis, Holladay 2, Olsen, and SRK / T is shown. To determine the exact indications for using these formulas, further studies are necessary taking into account the anterior chamber depth and a lesser degree of hyperopia.
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Saltanaeva, Elena Andreevna, and Andrey Vladimirovich Maister. "Optimization of calculations of the effects of spill fires during accidents on linear equipment." E3S Web of Conferences 140 (2019): 07002. http://dx.doi.org/10.1051/e3sconf/201914007002.
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The issue of industrial (in particular, fire) safety at hazardous production facilities is considered. The previously obtained optimization method is given for calculating the assessment of the influence of hazardous factors in the event of possible accidents on extended (linear) equipment during explosions of fuel-air mixtures. Optimization is based on accelerating the calculations of the potential damage probability of Qn(M0) using transformed formulas containing a single instead of a double integral. The transformed formulas for calculating the double integral obtained in were used to optimize the calculations for the case of a spill fire based on the recommended probit function Pr used to estimate the damage to people by thermal radiation. As an example of calculations, a rectilinear fragment of a pipeline on a plane, presented as a segment of a straight line, is considered. To obtain an assessment of effectiveness, 1000 sets of source data characterizing various emergency situations were randomly generated. Based on the calculations for these data sets, statistical results are presented that characterize the effectiveness of the proposed optimization method: a graph of the values of the multiplicity of the reduction in calculation time using the converted formulas; average value and standard deviation of the multiplicity of reduction of calculation time; the maximum deviation of the values calculated by the original and converted formulas.
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Liu, Jie, Shuang Xi Zhang, and Yu Feng He. "Investigation on Double-Tube Copper-Aluminum Column-Wing Type Radiators." Advanced Materials Research 243-249 (May 2011): 4883–86. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.4883.
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The calculation formulas are provided for calculating the heat release and metal thermal intensity of double-tube copper-aluminum Column-wing type radiator, and the reliability of the theoretical calculation is verified. The metal thermal intensity is taken as an optimization index, with theoretical calculations for different sorts of tube diameters and overall dimensions, obtains the optimalizing dimension of the radiator.
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Zhang, Yichi, Xiao Ying Liang, Shu Liu, Jacky W. Y. Lee, Srinivasan Bhaskar, and Dennis S. C. Lam. "Accuracy of Intraocular Lens Power Calculation Formulas for Highly Myopic Eyes." Journal of Ophthalmology 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/1917268.
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Purpose.To evaluate and compare the accuracy of different intraocular lens (IOL) power calculation formulas for eyes with an axial length (AL) greater than 26.00 mm.Methods.This study reviewed 407 eyes of 219 patients with AL longer than 26.0 mm. The refractive prediction errors of IOL power calculation formulas (SRK/T, Haigis, Holladay, Hoffer Q, and Barrett Universal II) using User Group for Laser Interference Biometry (ULIB) constants were evaluated and compared.Results.One hundred seventy-one eyes were enrolled. The Barrett Universal II formula had the lowest mean absolute error (MAE) and SRK/T and Haigis had similar MAE, and the statistical highest MAE were seen with the Holladay and Hoffer Q formulas. The interquartile range of the Barrett Universal II formula was also the lowest among all the formulas. The Barrett Universal II formulas yielded the highest percentage of eyes within ±1.0 D and ±0.5 D of the target refraction in this study (97.24% and 79.56%, resp.).Conclusions.Barrett Universal II formula produced the lowest predictive error and the least variable predictive error compared with the SRK/T, Haigis, Holladay, and Hoffer Q formulas. For high myopic eyes, the Barrett Universal II formula may be a more suitable choice.
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Zhou, Shun Hua, Jing Shan Shi, Quan Mei Gong, and Chang Ji. "Cumulative Strain Behaviour of Saturated Clay Under Transit Cyclic Loading." Advanced Materials Research 422 (December 2011): 409–15. http://dx.doi.org/10.4028/www.scientific.net/amr.422.409.
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Based on the dynamic triaxial test of typical soils in Hangzhou area, the existed empirical calculation formulas of cumulative pore pressure and cumulative plastic strain are analyzed to recharacterized variables such as the cyclic stress ratio and the static deviator stress, therefor the modified formulas are proposed. Parameters of cumulative deformation calculation model that suitable for this area are also determined according to dynamic triaxial tests. Thereafter the modified formulas is applied in a subway project under construction in Hangzhou. Results show that both the the cumulative plastic strain and cumulative pore pressure in dynamic triaxial test have the power exponential function relationship with the vibration number, and an inflection point appears in curve when amounts to approximately 1000. The improved formulas basicly tally with test results, of which the cumulative plastic strain formula coinsides better. The formulas work well in calculating the long-term settlement of subway projects in Hangzhou area.
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Movsisyan, A. B., and A. E. Egorov. "Nuances of preoperative care before cataract extraction. What do we overlook when performing biometry, calculating IOL power, and examining the eye?" Russian Journal of Clinical Ophthalmology 21, no. 3 (2021): 159–63. http://dx.doi.org/10.32364/2311-7729-2021-21-3-159-163.
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Modern cataract surgery is increasingly regarded as a refractive procedure. The focus has shifted from practicing and refining surgical steps towards personalized intraocular lens (IOL) choice based on the eye parameters of each individual. The best possible refractive outcome is now the priority. All components of biometry contribute to IOL power calculation accuracy. Therefore, any errors, a method of evaluating each parameter, and a technician’s experience are important. In addition, refraction, macular disorders, and prior surgical procedures affect IOL choice, preoperative care, and the extent of surgery. Moreover, subsequent changes in the IOL position that results in refractive errors after cataract surgery (this depends on the formula for IOL power calculation) should also be considered. The accuracy of IOL power calculation is affected by the inaccuracy of current biometry techniques and postoperative changes of the globe. Personalization of theoretical formulas provides better accuracy of IOL power calculations to meet modern trends in intraocular correction. Supplements containing macular pigments prevent macular degeneration and protect the macular zone. Keywords: cataract, refraction, cataract surgery, biometry, IOL power calculation, IOL power calculation formulas, retina, age-related macular degeneration. For citation: Movsisyan A.B., Egorov A.E. Nuances of preoperative care before cataract extraction. What do we overlook when performing biometry, calculating IOL power, and examining the eye? Russian Journal of Clinical Ophthalmology. 2021;21(3):159–163 (in Russ.). DOI: 10.32364/2311-7729-2021-21-3-159-163.
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Pershin, K. B., N. F. Pashinova, I. A. Likh, А. I. Tsygankov, and S. L. Legkikh. "Intraocular lenses optic power calculation with seven formulas in short eyes." POINT OF VIEW. EAST – WEST, no. 3 (September 28, 2021): 37–40. http://dx.doi.org/10.25276/2410-1257-2021-3-37-40.
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Purpose. The choice of the optimal formula for calculating the IOL optical power in patients with an axial eye length of less than 20 mm. Material and methods.A total of 78 patients (118 eyes) were included in theprospective study. Group I included 30 patients (52 eyes) with short eyes (average axial eye length of 19.60 ± 0.42 (18.54-20.0) mm), group II consisted of 48 patients (66 eyes) with a axial length (22.75 ± 0.46 (22.0-23.77) mm. Various monofocal IOL models were used. The average follow-up period was 13 months. IOL optical power was calculated using the SRK/T formula, retrospective comparison - according to the formulas Hoffer-Q, Holladay II, Olsen, Haigis, Barrett Universal II and Kane. Results. In group I, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK / T, Holladay 2 and Hoffer-Q (0.85; 0.78; 0.21; 0.17; 0.79; 0.73; 0.19 respectively). When comparing the formulas, significant differences were found for the formulas Hoffer-Q, Barrett Universal II and Kane in comparison with the formulas Haigis, Olsen, SRK / T and Holladay II (p <0.05) in all cases, respectively. In group I, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK / T, Holladay 2 and Hoffer-Q (0.15; 0.16; 0.23; 0.10; 0.19; 0.23; 0.29 respectively) In group II, there were no significant differences between the studied formulas (p> 0.05). Conclusion. This paper presents an analysis of data on the effectiveness of seven formulas for calculating the IOL optical power in short (less than 20 mm) eyes in comparison with the normal axial length. The advantage of the Hoffer-Q, Barrett Universal II and Kane formulas over Haigis, Holladay 2, Olsen, and SRK / T is shown. Key words: cataract; hypermetropia; short eyes; calculation of the IOL optical power.
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Pershin, K. B., N. F. Pashinova, I. A. Likh, and А. Y. Tsygankov. "Intraocular lenses optic power calculation with seven formulas in short eyes." Modern technologies in ophtalmology, no. 1 (May 29, 2021): 57–61. http://dx.doi.org/10.25276/2312-4911-2021-1-57-61.
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Purpose. The choice of the optimal formula for calculating the IOL optical power in patients with an axial eye length of less than 20 mm. Material and methods. A total of 78 patients (118 eyes) were included in the prospective study. 1st group included 30 patients (52 eyes) with short eyes (average axial eye length of 19.60±0.42 (18.54–20.0) mm), 2nd group consisted of 48 patients (66 eyes) with a axial length 22.75±0.46 (22.0–23.77) mm. Various monofocal IOL models were used. The average follow-up period was 13 months. IOL optical power was calculated using the SRK/T formula, retrospective comparison – according to the formulas Hoffer-Q, Holladay II, Olsen, Haigis, Barrett Universal II and Kane. Results. In 1st group, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK/T, Holladay II and Hoffer-Q (0.85, 0.78, 0.21, 0.17, 0.79, 0.73, 0.19 respectively). When comparing the formulas, significant differences were found for the formulas Hoffer-Q, Barrett Universal II and Kane in comparison with the formulas Haigis, Olsen, SRK/T and Holladay II (p<0.05) in all cases, respectively. In 2nd group, the mean absolute error was determined for the formulas Haigis, Olsen, Barrett Universal II, Kane, SRK/T, Holladay II and Hoffer-Q (0.15, 0.16, 0.23, 0.10, 0.19, 0.23, 0,29 respectively). In 2nd group, there were no significant differences between the studied formulas (p>0.05). Conclusion. This paper presents an analysis of data on the effectiveness of seven formulas for calculating the IOL optical power in short (less than 20 mm) eyes in comparison with the normal axial length. The advantage of the Hoffer-Q, Barrett Universal II and Kane formulas over Haigis, Holladay II, Olsen, and SRK/T is shown. Key words: cataract, hypermetropia, short eyes, calculation of the IOL optical power.
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Seddon, Colette, Laurell Lockitt, Sacha Dhanjal, and Michael Eisenhut. "Validation of Advanced Paediatric Life Support Formulas for Weight Calculation in a Multiethnic Population." ISRN Pediatrics 2012 (September 25, 2012): 1–4. http://dx.doi.org/10.5402/2012/869634.
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Introduction. The aims of this study were to validate the new formulas for weight calculation introduced by the advanced life support group (alsg) of the United Kingdom in 2011 and compare their performance to the formula currently used by the European Resuscitation Council (ERC) and other formulas and to check whether performance of formulas for weight calculation is affected by ethnic group and gender. Methods. Prospective audit of weight versus calculated weight comparing alsg formula with ERC, Luscombe, Argall, and Best Guess formulas analysed for gender, age, and ethnic groups. Results. Prospectively 599 children were included: 157 Asian, 268 Caucasian, and 174 children from other origin. In infants there was no difference between actual weight and alsg formula calculated weight. There was a progressively increased underestimation of weight year by year from 1 to 10 years of age using the ERC formula. In the 6–10 year age group the ERC formula underestimated the weight by a mean of 6.5 kg (21.8%, ) with the alsg and Luscombe formulas performing best. In 11-12 year old children the alsg formula estimated well. Conclusion. In one- to ten-year-old children, the Luscombe formula provided a better weight estimate than alsg and ERC formulas in a multiethnic population.
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Khan, Majid, and Muhammad Riaz. "COMPARATIVE STUDY BETWEEN VARIOUS PEDIATRICS DOSE CALCULATION FORMULAS: A CASE STUDY OF 12 YEARS CHILD FOR PARACETAMOL." International Journal of Research -GRANTHAALAYAH 8, no. 3 (May 26, 2020): 304–8. http://dx.doi.org/10.29121/granthaalayah.v8.i3.2020.161.
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In this piece of study one case evaluated relevant to the dose calculation in which six formulas utilized for calculation of optimal doses and comparison between these formulas as well as beauty of all formulas. The different formulas used like on the basis of age includes Young rules, Dilling rules, Bastedo rules, Crowling, on the basis of weight Clark and Majid formula used and for Body Surface Area Mosteller formula utilized. The result of the current study purports for one patient of Paracetamol dose in which Young formula result is 250 mg, Dilling 300mg, Bastedo 250mg, Crowling 270.9mg, on weight basis 278.5mg by Clark and Majid rule also 278.5 and 329mg by Mosteller Body Surface Area formula, the mean of the current result is 279.4mg that is nearest to weight formula considered as better and BSA formula shows 329mg that is in the category of therapeutic window because in British National Formulary Paracetamol dose ranges from 250-500mg and some authors reported Dilling rule is good due to simplicity and brevity. The current study concluded Dilling rule is the simplest one, weight base is nearest to average range and the most appropriate formula is BSA but slight lengthy in calculation. Dose calculation play crucial role in clinical condition of the patient and proper formula should be selected in order to get better therapeutic outcomes.
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Crozel, D., and M. David. "Global estimation variance: Formulas and calculation." Journal of the International Association for Mathematical Geology 17, no. 8 (November 1985): 785–96. http://dx.doi.org/10.1007/bf01034061.
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Kijima, T. "Accuracy of Intraocular Power Calculation Formulas." Japanese Journal of Ophthalmology 43, no. 6 (December 1999): 572. http://dx.doi.org/10.1016/s0021-5155(99)00137-9.
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Melles, Ronald B., Jack T. Holladay, and William J. Chang. "Accuracy of Intraocular Lens Calculation Formulas." Ophthalmology 125, no. 2 (February 2018): 169–78. http://dx.doi.org/10.1016/j.ophtha.2017.08.027.
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Melles, Ronald B., Jack X. Kane, Thomas Olsen, and William J. Chang. "Update on Intraocular Lens Calculation Formulas." Ophthalmology 126, no. 9 (September 2019): 1334–35. http://dx.doi.org/10.1016/j.ophtha.2019.04.011.
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Sperka, Petr, Ivan Krupka, and Martin Hartl. "Analytical Formula for the Ratio of Central to Minimum Film Thickness in a Circular EHL Contact." Lubricants 6, no. 3 (September 7, 2018): 80. http://dx.doi.org/10.3390/lubricants6030080.
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Prediction of minimum film thickness is often used in practice for calculation of film parameter to design machine operation in full film regime. It was reported several times that majority of prediction formulas cannot match experimental data in terms of minimum film thickness. These standard prediction formulas give almost constant ratio between central and minimum film thickness while numerical calculations show ratio which spans from 1 to more than 3 depending on M and L parameters. In this paper, an analytical formula of this ratio is presented for lubricants with various pressure–viscosity coefficients. The analytical formula is compared with optical interferometry measurements and differences are discussed. It allows better prediction, compared to standard formulas, of minimum film thickness for wide range of M and L parameters.
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Yue, Zhu, Jiang Shengyao, Yang Xingtuan, and Duan Riqiang. "Study on divergence approximation formula for pressure calculation in particle method." Journal of Computational Multiphase Flows 10, no. 4 (August 16, 2018): 159–69. http://dx.doi.org/10.1177/1757482x18791896.
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The moving particle semi-implicit method is a meshless particle method for incompressible fluid and has proven useful in a wide variety of engineering applications of free-surface flows. Despite its wide applicability, the moving particle semi-implicit method has the defects of spurious unphysical pressure oscillation. Three various divergence approximation formulas, including basic divergence approximation formula, difference divergence approximation formula, and symmetric divergence approximation formula are proposed in this paper. The proposed three divergence approximation formulas are then applied for discretization of source term in pressure Poisson equation. Two numerical tests, including hydrostatic pressure problem and dam-breaking problem, are carried out to assess the performance of different formulas in enhancing and stabilizing the pressure calculation. The results demonstrate that the pressure calculated by basic divergence approximation formula and difference divergence approximation formula fluctuates severely. However, application of symmetric divergence approximation formula can result in a more accurate and stabilized pressure.
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Jiang, Li Zhong, Wang Bao Zhou, and Yao Luo. "Simple Formulate for Distortional Buckling Load of Liffed Channel Aluminium Alloy Members under Axial Force." Advanced Materials Research 378-379 (October 2011): 230–36. http://dx.doi.org/10.4028/www.scientific.net/amr.378-379.230.
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Aluminium alloy members under axial force have broad application in structural field. Owing to low elastic modulus, aluminium alloy members are easier buckling than steel members. Based on the reasonable and equivalent calculation model and the related calculation formulas of rotational restraint stiffness kφ, lateral restraint stiffness kx, and distortional buckling critical half-wave length λ that provided by lipped channel web plate to flange under longitudinal distribution stress, the distortional buckling load calculation formula of the lipped channel is derived combining the thin-walled bar buckling theory in elastic medium. The distortional buckling loads and distortional buckling critical half-wave lengths at the different wall thickness have been calculated using the calculation formulas of this paper, and the results have been comparatived with the finite strip method. The comparison results show that: the average ratio of caculation results from formulas of this paper and results from CUFSM is 0.997and0.971 respectively,the corresponding variance is 2.9*10-5and 7.5*10-5. So the calculation results of this paper is in good agreement with the finite strip software, the calculation formula of this paper has enough calculation precision and good stability. At the same time, the calculation results of this paper is more concise than calculation formula for the same type, easy to be applied, may be used in practical applications and taken account into design codes and guidelines.
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Chepilko, S. O. "Refined calculation of complex steel-reinforced concrete beams by limit states." Вестник гражданских инженеров 18, no. 6 (2021): 51–65. http://dx.doi.org/10.23968/1999-5571-2021-18-6-51-65.
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The paper considers the issues of calculating complex steel-reinforced concrete beams by the limit states on the basis of the nonlinear diagram of concrete deformation ε-σ. Sargin`s formula normalized in Eurocodes and Russian norms is taken as a reference diagram. A comparison is made with the calculation for the formation of an ideal plastic hinge. There are pointed out significant discrepancies (up to 11%) in some calculation cases. The possibility of using the proposed formulas for calculating conventional reinforced concrete beams of complicated cross-section is indicated.
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Crocombette, Jean-Paul, and Christian Van Wambeke. "Quick calculation of damage for ion irradiation: implementation in Iradina and comparisons to SRIM." EPJ Nuclear Sciences & Technologies 5 (2019): 7. http://dx.doi.org/10.1051/epjn/2019003.
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Binary collision approximation (BCA) calculation allows for two types of damage calculation: full cascade and quick calculations. Full cascade mode describes fully the cascades while in quick calculations, only the trajectory of the ion is followed and effective formulas give an estimation of the damage resulting from each collision of the ion. We implement quick calculation of damage in the Iradina code both for elemental and multi-component solids. Good agreement is obtained with SRIM. We show that quick calculations are unphysical in multi-component systems. The choice between full cascade and quick calculations is discussed. We advise to favour full cascade over quick calculation because it is more grounded physically and applicable to all materials. Quick calculations remain a good option for pure solids in the case of actual quantitative comparisons with neutron irradiations simulations in which damage levels are estimated with the NRT (Norgett-Robinson and Torrens) formulas.
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Shao, Yan, Yi Guan, and Wei Zhong Xing. "Analysis and Calculation of the Additional Stress in the Foundation under Trapezoid-Distribution Load." Applied Mechanics and Materials 353-356 (August 2013): 446–49. http://dx.doi.org/10.4028/www.scientific.net/amm.353-356.446.
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Based on J. V. Boussinesq's solution, the additional stress in the foundation is calculated under the trapezoid-distributed line load, and with the help of the line load, a formula is derived for calculating the additional stress in the foundation under the center line of trapezoid-distribution load along the Y-axis. By means of the formula, the different calculation formulas of the additional stress are determined under the load of rectangular, triangular and semi-infinite long stripe along with the change of the initial conditions. The formula can be applied to the additional stress's calculation of space problem more widely and is better than that seems to be dispersed in the reference books. Therefore, the calculation result has practical significance.
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Rogova, Elena, Gabriel Lodewijks, and Mary Ann Lundteigen. "Analytical formulas of PFD and PFH calculation for systems with nonconstant failure rates." Proceedings of the Institution of Mechanical Engineers, Part O: Journal of Risk and Reliability 231, no. 4 (March 20, 2017): 373–82. http://dx.doi.org/10.1177/1748006x17694999.
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Most analytical formulas developed for the PFD and PFH calculation assume a constant failure rate. This assumption does not necessarily hold for system components that are affected by wear. This article presents methods of analytical calculations of PFD and PFH for an M-out-of-N redundancy architecture with nonconstant failure rates and demonstrates its application in a simple case study. The method for PFD calculation is based on the ratio between cumulative distribution functions and includes forecasting of PFD values with a possibility of update of failure rate function. The approach for the PFH calculation is based on simplified formulas and the definition of PFH. In both methods, a Weibull distribution is used for characteristics of the system behavior. The PFD and PFH values are obtained for low, moderate and high degradation effects and compared with the results of exact calculations. Presented analytical formulas are a useful contribution to the reliability assessment of M-out-of-N systems.
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Aleksandrov, A. S., A. V. Smirnov, and T. V. Semenova. "Stress Investigation in Pavement Layers and a New Nalculation Model." Materials Science Forum 945 (February 2019): 813–20. http://dx.doi.org/10.4028/www.scientific.net/msf.945.813.
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The paper is devoted to the comparison results of experimental data and theoretical stress calculations (arising in pavement layers made from granular materials). The formulas of continuum mechanics and mechanics for granular materials and mathematical dependences, got in accordance with engineering calculation method, were taken as a calculation model. The experimental stress values, measured by Steven B.D. using ring stand (University of Canterbury), were applied as a standard. The ring stand ley us employ moving loads to the stand segments with pavement constructed over the ring stand. It was discovered that the best match of values of experimental and calculation data is got by stress computing based on formulas of mechanics for granular materials (M.E. Harr or I.I. Kandaurov) or continuum mechanics, but with O.C. Frohlich parameter added to С.R. Foster, R.G. Ahlvin and H.H. Ulery’s formula. This Frohlich parameter can be taken as a material parameter. In the conclusion the authors show the way of modification of the well-known approaches in mechanics for granular materials. This new way makes possible to calculate minimum principal stress σ3.The modified mathematical relationships of principal stress calculation can be used in models for elastic, plastic, elastic-plastic deformation calculations and in conditions of plasticity.
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Iijima, Kei, Kazutaka Kamiya, Yoshihiko Iida, and Nobuyuki Shoji. "Comparison of Predictability Using Barrett Universal II and SRK/T Formulas according to Keratometry." Journal of Ophthalmology 2020 (June 19, 2020): 1–5. http://dx.doi.org/10.1155/2020/7625725.
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Purpose. To compare the predictability of intraocular lens (IOL) power calculation using the Barrett Universal II and the SRK/T formulas, according to the keratometry. Methods. We retrospectively reviewed the clinical charts of 335 consecutive eyes undergoing standard cataract surgery. IOL power calculations were performed using the Barrett Universal II and the SRK/T formulas. We compared the prediction error, the absolute error, and the percentages within ±0.25, ±0.5, and ±1.0 D of the targeted refraction, 1 month postoperatively, and also investigated the relationship of these outcomes with the keratometric readings, using the two formulas. Results. The prediction error using the SRK/T formula was significantly more myopic than that using the Barrett Universal II formula (the paired t-test, p<0.001). The absolute error using the SRK/T formula was significantly larger than that using the Barrett Universal II formula (p=0.006). We found a significant correlation between the prediction error and the keratometric readings using the SRK/T formula (Pearson correlation coefficient, r = −0.522, p<0.001), but there was no significant correlation between them using the Barrett Universal II formula (r = −0.031, p=0.576). Conclusions. The Barrett Universal II formula provides a better predictability of IOL power calculation and is less susceptible to the effect of the corneal shape, than the SRK/T formula. The Barrett Universal formula, instead of the SRK/T formula, may be clinically helpful for improving the refractive accuracy, especially in eyes with steep or flat corneas.
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Zhou, Jian, Chuan Huang, Mingxuan Zhao, and Hui Li. "Entropy and Semi-Entropies of LR Fuzzy Numbers’ Linear Function with Applications to Fuzzy Programming." Entropy 21, no. 7 (July 16, 2019): 697. http://dx.doi.org/10.3390/e21070697.
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As a crucial concept of characterizing uncertainty, entropy has been widely used in fuzzy programming problems, while involving complicated calculations. To simplify the operations so as to broaden its applicable areas, this paper investigates the entropy within the framework of credibility theory and derives the formulas for calculating the entropy of regular LR fuzzy numbers by virtue of the inverse credibility distribution. By verifying the favorable property of this operator, a calculation formula of a linear function’s entropy is also proposed. Furthermore, considering the strength of semi-entropy in measuring one-side uncertainty, the lower and upper semi-entropies, as well as the corresponding formulas are suggested to handle return-oriented and cost-oriented problems, respectively. Finally, utilizing entropy and semi-entropies as risk measures, two types of entropy optimization models and their equivalent formulations derived from the proposed formulas are given according to different decision criteria, providing an effective modeling method for fuzzy programming from the perspective of entropy. The numerical examples demonstrate the high efficiency and good performance of the proposed methods in decision making.
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Jiang, Shuan, Li Li Bai, and Wei Chen Xue. "Calculation of Crack Width of Steel-Concrete Composite Beam Prestressed with Internal Tendons." Advanced Materials Research 889-890 (February 2014): 1445–49. http://dx.doi.org/10.4028/www.scientific.net/amr.889-890.1445.
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Steel-concrete composite beam prestressed with internal tendons (SCCPIT) is composed of prestressed concrete slab, steel beam and shear connectors, etc. At present, there is no calculation formula for crack width of SCCPIT in current design codes like European standard Eurocode 4 or American code ASSHTO LERD Bridge Design Specification (2004). In this paper, calculation formulas for crack width of nonprestressed steel-concrete composite beam provided in Code for Design of SteelConcrete Composite Structure (DL/T 50851999) were adopted as a basis for modification. On the basis of available test results, calculation formulas for uneven coefficient of reinforcement strain and average crack space were modified by consideration of concrete slab width and combined force ratio. Hence, empirical calculation formulas for crack width of SCCPIT under negative moment were proposed. In order to verify accuracy of proposed formulas, available test results including results of five simply supported SCCPITs previously conducted by author were introduced, and comparisons indicated that calculated values were in good agreement with test results.
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Ямилев, Марат Замирович, Азат Маратович Масагутов, Александр Константинович Николаев, Владимир Викторович Пшенин, Наталья Алексеевна Зарипова, and Кристина Игоревна Плотникова. "Modified equations for hydraulic calculation of thermally insulated oil pipelines for the case of a power-law fluid." SCIENCE & TECHNOLOGIES OIL AND OIL PRODUCTS PIPELINE TRANSPORTATION, no. 4 (September 21, 2021): 388–95. http://dx.doi.org/10.28999/2541-9595-2021-11-4-388-395.
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Теплогидравлический расчет неизотермических трубопроводов является наиболее важным гидравлическим расчетом в рамках решения задач обеспечения надежности и безопасности работы нефтепроводной системы. Для практических расчетов применяются формулы Дарси - Вейсбаха и Лейбензона. При этом в ряде случаев (короткие теплоизолированные участки, поверхностный обогрев нефтепроводов) можно использовать упрощенный подход к расчету, пренебрегая изменением температуры или учитывая температурные поправки. В настоящее время формулы для аналитического расчета движения высоковязких нефтей в форме уравнения Лейбензона получены только для ньютоновской и вязкопластичной жидкостей. Для степенной жидкости соответствующие зависимости отсутствуют, расчет ведется с использованием формулы Дарси - Вейсбаха. Целью настоящей статьи является представление формулы Дарси - Вейсбаха для изотермических течений степенной жидкости в форме уравнения Лейбензона. Данное представление позволит упростить процедуру проведения аналитических выкладок. В результате получены модифицированные уравнения Лейбензона для определения потери напора на участке нефтепровода в диапазоне индекса течения от 0,5 до 1,25. В указанном диапазоне относительное отклонение от результатов расчетов с использованием классических формул Метцнера - Рида и Ирвина не превышает 2 %. The thermal-hydraulic calculation of non-isothermal pipelines is the most important hydraulic calculation in the framework of solving the problems of ensuring the reliability and safety of the oil pipeline system. For practical calculations, the Darcy - Weisbach and Leibenson formulas are used. Moreover, in a number of cases (short heat-insulated sections, surface heating of oil pipelines), a simplified approach to the calculation can be used, neglecting temperature changes or taking into account temperature corrections. At present, formulas for the analytical calculation of the motion of high-viscosity oils in the form of the Leibenson equation have been obtained only for Newtonian and viscoplastic fluids. For a power-law fluid, there are no corresponding dependences; the calculation is carried out using the Darcy - Weisbach formula. The purpose of this article is to present the Darcy - Weisbach formula for isothermal flows of a power-law fluid in the Leibenzon form, which will simplify the procedure for performing analytical calculations. The modified Leibenzon equations are obtained to determine the head loss in the oil pipeline section in the range of the flow index from 0.5 to 1.25. In the specified range, the relative deviation from the results of calculations using the classical Metzner - Reed and Irwin formulas does not exceed 2 %.
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LIBERA, Michał. "A SIMPLIFIED WAY OF ESTIMATING A DYNAMIC LOAD RATING FOR THRUST ROLLER BEARINGS." Tribologia 289, no. 1 (March 31, 2020): 49–55. http://dx.doi.org/10.5604/01.3001.0014.0844.
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The method of calculating the bearing capacity of rolling bearings is described in the ISO 281 standard. The calculation procedure for roller thrust bearings presented there, depending on the value of the nominal bearing angle, requires the selection of one of two formulas. Then, using the table, one reads the value of the factor depending on the geometry of the bearing components. To facilitate and speed up calculations (and perhaps also increase their accuracy), this article proposes a formula that is adapted to numerical applications, replaces linear interpolation with a proper non-linear function and allows calculations to be made for a specific value of the nominal bearing angle, but not within the range of 15°. The difference between the values calculated according to the proposed formula and the value calculated according to ISO 281 is, on average, around 3%.
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Edneral, V. F., and O. D. Timofeevskaya. "Normal form method in search for periodic solutions of ordinary differential equations. Case of the fourth order." Information and Control Systems, no. 6 (December 18, 2018): 24–34. http://dx.doi.org/10.31799/1684-8853-2018-6-24-34.
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Introduction:The method of resonant normal form is based on reducing a system of nonlinear ordinary differential equations to a simpler form, easier to explore. Moreover, for a number of autonomous nonlinear problems, it is possible to obtain explicit formulas which approximate numerical calculations of families of their periodic solutions. Replacing numerical calculations with their precalculated formulas leads to significant savings in computational time. Similar calculations were made earlier, but their accuracy was insufficient, and their complexity was very high.Purpose:Application of the resonant normal form method and a software package developed for these purposes to fourth-order systems in order to increase the calculation speed.Results:It has been shown that with the help of a single algorithm it is possible to study equations of high orders (4th and higher). Comparing the tabulation of the obtained formulas with the numerical solutions of the corresponding equations shows good quantitative agreement. Moreover, the speed of calculation by prepared approximating formulas is orders of magnitude greater than the numerical calculation speed. The obtained approximations can also be successfully applied to unstable solutions. For example, in the Henon — Heyles system, periodic solutions are surrounded by chaotic solutions and, when numerically integrated, the algorithms are often unstable on them.Practical relevance:The developed approach can be used in the simulation of physical and biological systems.
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Yang, Qiuwei, and Xi Peng. "An Exact Method for Calculating the Eigenvector Sensitivities." Applied Sciences 10, no. 7 (April 9, 2020): 2577. http://dx.doi.org/10.3390/app10072577.
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Eigenvector sensitivities are often used in many engineering problems such as structural vibration control, optimization design, model updating and damage identification. So far, modal superposition method and Nelson’s method are the two main methods for exactly calculating eigenvector sensitivities. However, modal superposition method has a great limitation in applications because it needs all the eigenvectors in its calculation. Although Nelson’s method does not need to use all the eigenvectors, there is no unified sensitivity calculation formula for each eigenvector. In this paper, a new exact method for calculating the eigenvector sensitivity is proposed. The explicit expressions for the first-order and second-order sensitivities of eigenvectors are derived, and strict proof is given. The developed eigenvector sensitivity formulas are simple and convenient in programming. The proposed method is as powerful as Nelson’s method, but much more easy to use. Two numerical examples are used to demonstrate the proposed method and the results show that the developed eigenvector sensitivity formulas are exact and reliable.
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Wen, Hui, and Feng Ling Li. "A Simplified Formula to Calculate the Initial Value of Iteration for Contracted Depth in Quadratic Parabola Shaped Channels." Applied Mechanics and Materials 744-746 (March 2015): 1039–44. http://dx.doi.org/10.4028/www.scientific.net/amm.744-746.1039.
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At present, the complexity of calculation process and expression form of the initial value of iteration for contracted depth in quadratic parabola shaped channels,Seek a new iterative initial value formula for contracted depth in quadratic parabola shaped channels. Through an identical deformation on the basic equation for contracted depth in quadratic parabola shaped channels. Deduce the iterative formula for computing the quadratic parabola section contraction water depth. Introduction the dimensionless contraction water depth concept, plot the dimensionless contraction water depth and the dimensionless parameter relationship curves. Determine the iterative formula of initial value form for quadratic parabolic shaped channels, and based on the theory of optimum fitting, by the minimum residual standard differential and simple form of formula as the goal, the initial iteration value formula for calculation contracted depth in quadratic parabola shaped channels was obtained. It is greatly accelerating the convergence rate iterative calculations. The calculation of a practical case and error analysis of the depth calculations show that in the utility range of , its maximum relative error is less than 0.26% after performing one iteration. This formula has definite physics concept, easy calculation, high precision and wide range compared with the existing formulas. It will bring great convenience for designers.
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Li, Cong, Ke Jie Huang, Xiao Qing Zhang, and Nai Wen Hu. "Wind Turbine Grounding Resistance Numerical Calculation." Advanced Materials Research 1065-1069 (December 2014): 3414–21. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.3414.
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With the increase capacity of wind turbines, grounding device's influence on the equipment and personal safety is becoming more and more significant. In order to calculate the grounding resistance of a wind turbine more accurately, in this paper, based on the Neumann integral formula and the average potential method is applied to derive a formula which can calculate the value of grounding resistance. A general MATLAB program corresponding to the calculation formula is compiled. By comparing the numerical value with the empirical analysis results and building a grounding resistance measurement test platform the correctness of the formulas and program is verified.
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Bueno, M., and AKT Assis. "Equivalence between the formulas for inductance calculation." Canadian Journal of Physics 75, no. 6 (June 6, 1997): 357–62. http://dx.doi.org/10.1139/p96-146.
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Pruseth, Kamal L. "Calculation of the CIPW norm: New formulas." Journal of Earth System Science 118, no. 1 (February 2009): 101–13. http://dx.doi.org/10.1007/s12040-009-0010-0.
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Chung, Jinkwon, Jennifer J. Bu, and Natalie A. Afshari. "Advancements in intraocular lens power calculation formulas." Current Opinion in Ophthalmology 33, no. 1 (October 29, 2021): 35–40. http://dx.doi.org/10.1097/icu.0000000000000822.
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Haigis, Wolfgang. "Intraocular Lens Calculation After Refractive Surgery." European Ophthalmic Review 06, no. 01 (2012): 21. http://dx.doi.org/10.17925/eor.2012.06.01.21.
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More and more patients who have had corneo-refractive surgery present for intraocular lens (IOL) implantation. IOL calculation in these patients is still a challenge. After refractive surgery, if eyes are treated as normal eyes, high hyperopic errors can occur in previously myopic eyes and moderate myopic errors in formerly hyperopic eyes. Three main sources for these errors can be identified: the radius measurement error, the keratometer index error and the IOL formula error. The literature presents a confusing variety of procedures and formulas to cope with this situation. An analysis of the available literature reveals the different methods used to address the individual error contributions, the magnitude of which is assessed by model calculations. The most relevant formulas for clinical practice are the no-history procedures, which require no previous patient data. Using these methods to calculate IOL power after refractive surgery makes it possible to obtain clinical outcomes of a similar quality to that for normal eyes.
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Prodous, O. A., and D. I. Shlychkov. "Recommended dependence for hydraulic calculation of gravity drainage networks in order to improve the ecological well-being of cities." IOP Conference Series: Earth and Environmental Science 937, no. 4 (December 1, 2021): 042021. http://dx.doi.org/10.1088/1755-1315/937/4/042021.
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Abstract In the submitted article comparison of two calculated dependences - formulas of A. Chézyand and N.F. Fedorov used for the hydraulic calculation of gravity drainage networksare presented. For a specific example, dependence is revealed - the A. Chézy formula, which gives the highest accuracy when calculating the hydraulic slope of a gravity pipeline. The appearance of the A. Chézy formula has been clarified due to the introduction of the concept of the reduced inner diameter of the pipes. The graph of the dependence i=f (dred) is plotted, indicating that the refined form of the A. Chézy formula is more accurate. It is recommended to use the A. Chézy formula in a refined form for the hydraulic calculation of gravity drainage networks. It is proposed to develop calculation tables for the hydraulic calculation of drainage networks with internal deposits. The analysis of the calculated dependencies for the hydraulic calculation of gravity drainage networks with internal deposits presented in the paper allows recommending for practical use the formula of A. Chézy refined by the authors, according to which the authors propose to develop the Reference manual “Tables for the hydraulic calculation of gravity drainage networks with internal deposits”.
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Yamanin, Alexander Ivanovich, and Vladimir Anatoljevich Zhukov. "On problem of calculating longitudinal vibrations of piston engine crankshaft." Vestnik of Astrakhan State Technical University. Series: Marine engineering and technologies 2021, no. 4 (November 30, 2021): 75–83. http://dx.doi.org/10.24143/2073-1574-2021-4-75-83.
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One of the initial stages of calculating the crankshaft longitudinal vibrations is developing an oscillatory system model, which includes the determination of longitudinal pliability (rigidity) of elastic sections. If it is impossible to determine the pliability experimental, the empiric formulas or the final element method (FEM) are used. There are given the values of crank longitudinal pliability of the crankshafts of different marine engine types found by using the formulas of L. Gugliemotti – R. Machciotta, P. Draminsky, E. Y. Gorbunov, S. F. Dorey, N. S. Skorchev, V. S. Stoyanov, etc. It is shown that the calculation results obtained from these formulas for the same engine significantly differ; therefore, the choice of one or another empirical formula for practical calculations is difficult. The preference of using FEM for determining the longitudinal (axial) compliance of cranks and other areas with complex geometric shapes has been proven. The possibility of its application is also shown to determine the longitudinal disturbing force as the reaction of the crankshaft support against the action of the radial force exerted to the connecting rod journal. It is proposed to use, along with empirical formulas, regression equations connecting the longitudinal compliance of the cranks with a significantly larger number of their design dimensions.
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Konoplev, N. G., and G. E. Korobkov. "Liquid Energy Reduction with Centrifugal Rotating Motion." IOP Conference Series: Earth and Environmental Science 988, no. 3 (February 1, 2022): 032093. http://dx.doi.org/10.1088/1755-1315/988/3/032093.
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Abstract This article provides equation for calculating the pressure loss for a fluid and energy for a rolling ball moving in a logarithmic spiral from the action of inertial forces. Classical formulas give incorrect results when calculating coils with a changing twist radius. The calculation of the parameters of the fluid flow in the spiral bend and in the blades of the centrifugal impeller can now be determined only by numerical methods of calculation and, as such, formulas reflecting the energy losses associated with inertial forces do not yet exist. Based on the results of experimental and theoretical work, formulas were obtained that describe the energy losses of a liquid and a ball, when they move along a logarithmic spiral. For the correct derivation of formulas for a moving fluid, it was first necessary to obtain formulas for a rolling ball and a material point. The movement in a logarithmetic spiral is the basis for the movement of particles in a vortex.
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Yun, Yong Feng, and De Lun Wu. "Discussion on the Calculation Method of the Deep Buried Tunnel Surrounding Rock Loose Pressure." Applied Mechanics and Materials 193-194 (August 2012): 757–61. http://dx.doi.org/10.4028/www.scientific.net/amm.193-194.757.
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Adopted the load-structure model to tunnel structure design calculation, our country often use surrounding rock pressure experience calculation formula, This paper analysed the problems existing in the experience calculation formula and calculated the surrounding rock pressure have influence on calculation results of tunnel structure internal force with the formulas, and at last given out more actual modification formula, the surrounding rock stress is continuity with the formula calculated, it is more actual than the traditional experience formula, provided a new way for accurate calculated the surrounding rock pressure.
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Zhang, Jinquan, Pengfei Li, Wanheng Li, Yan Mao, and Zhenhua Dong. "Simplified Calculation of Pylon Top Displacement of Multi-Pylon Suspension Bridge." Transportation Research Record: Journal of the Transportation Research Board 2673, no. 10 (June 4, 2019): 814–25. http://dx.doi.org/10.1177/0361198119850157.
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The long-span multi-pylon suspension bridge is the subject of growing interest. Under live load, the longitudinal deflection of the mid-pylon is an important control parameter for a multi-pylon suspension bridge design. It is important to establish a simplified method of calculating pylon deflection for the preliminary design and selection of a multi-pylon suspension bridge. Based on deflection theory and deformation compatibility condition, considering main cable horizontal constraints and the interaction among pylons and girders with the methods of equivalent stiffness and moment distribution, the simplified calculation formulas of pylon displacement at the top for three-, four-, and five-pylon suspension bridges are derived. The validity of the formulas are verified by model experiment, real bridge testing, and finite-element analysis. For a floating system, the error between the simplified formula and the finite element method is less than 10%, and that of the model experiment is within 25%. For a consolidation system, the error between the simplified formula and the finite element method is within 16%, and that of the real bridge testing is less than 11%. As the number of pylons increases, the simplified formulas tend to be less accurate.
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Zhang, Chenguang, Guangzheng Dai, Emmanuel Eric Pazo, Ling Xu, Xianwei Wu, Hongda Zhang, Tiezhu Lin, and Wei He. "Accuracy of intraocular lens calculation formulas in cataract patients with steep corneal curvature." PLOS ONE 15, no. 11 (November 20, 2020): e0241630. http://dx.doi.org/10.1371/journal.pone.0241630.
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Objective To compare the accuracy of five kinds of intraocular lens calculation formulas (SRK/T, Haigis, Hoffer Q, Holladay and Barrett Universal Ⅱ) in cataract patients with steep curvature cornea ≥ 46.0 diopters. Methods This is a retrospective study of cataract phacoemulsification combined with intraocular lens implantation in patients with steep curvature cornea (corneal curvature ≥ 46D). The refractive prediction errors of IOL power calculation formulas (SRK/T, Haigis, Holladay, Hoffer Q, and Barrett Universal II) using User Group for Laser Interference Biometry (ULIB) constants were evaluated and compared. Objective refraction results were assessed at one month postoperatively. According to axial length (AL), all patients were divided into three groups: short AL group (<22mm), normal AL group (>22 to ≤24.5mm) and long AL group (>24.5mm). Calculate the refractive error and absolute refractive error (AE) between the actual postoperative refractive power and the predicted postoperative refractive power. The covariance analysis was used for the comparison of five formulas in each group. The correlation between the absolute refractive error and AL from every formula were analyzed by Pearson correlation test, respectively. Result Total 112 eyes of 83 cataract patients with steep curvature cornea were collected. The anterior chamber depth (ACD) was a covariate in the short AL group in the covariance analysis of absolute refractive error (P<0.001). The SRK/T and Holladay formula had the lowest mean absolute error (MAE) (0.47D), there were statistically significant differences in MAE between the five formulas for short AL group (P = 0.024). The anterior chamber depth had no significant correlation in the five calculation formulas in the normal AL group and long AL group (P = 0.521, P = 0.609 respectively). In the normal AL group, there was no significant difference in MAE between the five calculation formulas (P = 0.609). In the long AL group, Barrett Universal II formula had the lowest MAE (0.35), and there were statistically significant differences in MAE between the five formulas (P = 0.012). Over the entire AL range, the Barrett Universal II formula had the lowest MAE and the highest percentage of eyes within ± 0.50 D, ± 1.00 D, and ± 1.50 D (69.6%, 93.8%, and 98.2% respectively). Conclusion Compared to SRK/T, Haigis, Hoffer Q, and Holladay, Barrett Universal Ⅱ formula is more accurate in predicting the IOL power in the cataract patients with steep curvature cornea ≥ 46.0 diopters.
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Doroshenko, Margarita. "The Concept of “Risk Content” and its Calculation for the Investment Project Work." SHS Web of Conferences 110 (2021): 04006. http://dx.doi.org/10.1051/shsconf/202111004006.
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The subject of the article is the concept of "risk content" introduced by the author and the peculiarities of its calculation for the investment project work. The purpose of the article is to provide an investor with practical tools for calculating the risk content of the project work. As a result of calculations, formulas for calculating resource losses and the risk content of the project work are found. The area of possible practical application of the research results is the investor's activity when investing in an investment project.
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Tian, Zhong Lan, Heng Lin Yang, Xiang Zhen Yan, and Zhi Qian Xu. "Collapsing Pressure of Casing Located at the Bend Part of Casing-Exit Sidetracking Well." Advanced Materials Research 383-390 (November 2011): 1884–90. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.1884.
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Depending on the mechanical characteristics of casing located at the bending part of sidetrack horizontal well, the calculation model of casing collapsing strength under the effect of bending load is established, and corresponding theoretical formulae is derived. During the process of deducing formulas, the influence of bending load on the casing section out of roundness is ignored, which made the calculation formula benefits intuition and practicality comparing to the T.Tamano formula. The result of this paper is verified through the simulation value and laboratory test of casing used in the Jilin oilfield. It shows that the formula of this paper can meet the engineering commands; the axial load is significant to affect casing collapsing strength, and in the actual production process should be strictly controlled.