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1

Catalyst regeneration techniques in naphtha reforming: Short review

Gupta Aviral, Gupta S. K.

Chemical and Process Engineering

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2022

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Vol. 43, nr 2

101–-108

EN

Catalytic reforming is an important intermediate in the processing of crude (naphtha in particular) to obtain gasoline. The catalyst used in the process (platinum) is quite expensive and may negatively impact the business if not used judiciously. The aforesaid not only refers to the reduction in loss of the catalyst per unit of gasoline produced but also to the manufacturing of an environmentally friendlier product alongside which is the need of the planet and also a necessity to meet the increasingly strict government norms. In order to meet the above requirements, various refineries around the world use various well-known conventional methods which depend on the quality and quantity of crude manufactured by them. This paper focuses on highlighting recent advancements in methods of catalytic regeneration (CR) in the reforming unit of petroleum industries to produce high octane gasoline, without any major replacements in their existing setup. Research papers formulated by the application of methodologies involving non-linear models and real-time refinery data have only been considered to avoid any deviations/errors in practical applications. In-depth analysis of these papers has led to the origin of some ideas which have been included as suggestions and can be considered as subjects of further research. In all, the objective of the paper is to serve as a reference for researchers and engineers working on devising optimum methods to improve the regeneration of reforming catalysts.

2

Flexural rehabilitation of steel beam with CFRP and BFRP fabrics – A comparative study

Bastani Amirreza, Das Sreekanta, Kenno Sara Y.

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 3

871--882

EN

This paper compares the performance of structural steel beams retrofitted with two different fiber reinforced polymer (FRP) fabrics: Carbon FRP (CFRP) and Basalt FRP (BFRP) fabrics. A total of eight steel beams with and without corrosion defect in the flexural tension zone were tested under 4-point bending load. The study found that the use of both FRP fabrics resulted in reduced ductility, however, ductility of beams retrofitted with BFRP fabric is much higher than that of the beams retrofitted with CFRP fabric of similar thickness. The study also found that both FRPs fabrics are effective in increasing the ultimate load, yield load, and elastic stiffness of beams, however, number of BFRP fabric layers required is higher than the number of CFRP fabrics. The structural behavior of steel beams including the complex behavior of rupture in the FRP fabrics were successfully modeled using a commercially finite element software and a good correlation was obtained between the finite element models and the lab specimens. Validated finite element model was used to obtain additional information that could not be obtained from the experimental study. This study concludes that the Basalt fabric offers a competitive and green alternative to the Carbon fabric.

3

Exponential temperature effect on frequencies of a rectangular plate of non-linear varying thickness: a quintic spline technique

Gupta A. K., Mamta J.

Journal of Theoretical and Applied Mechanics

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2014

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Vol. 52 nr 1

15--24

EN

The differential equation governing the transverse motion of an elastic rectangular plate of non-linear thickness variation with thermal gradient has been analyzed on the basis of classi- cal plate theory. Following Levy’s approach, i.e. the two parallel edges are simply supported, the fourth-order differential equation governing the motion of such plates of non-linear vary- ing thickness in one direction with exponentially temperature distribution has been solved by using the quintic splines interpolation technique for two different combinations of clamped and simply supported boundary conditions at the other two edges. An algorithm for com- puting the solution of this differential equation is presented for the case of equal intervals. The effect of thermal gradient together with taper constants on the natural frequencies of vibration is illustrated for the first three modes of vibration.

4

Non-linearity on pull-out test of cohesive soil using low tensile strengths of geogrids

Widodo S., Ibrahim A. M.

Challenges of Modern Technology

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2014

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Vol. 5, no. 1

34--37

EN

Influence of geosynthetics inserted into cohesive granular soil was obviously investigated using geosynthetics-soil-interaction-testing device (ITD). Observations were already made during undertaking pull-out test, and then the results revealed that a correlation between shear stress and normal stress exhibits non-linear behaviour. In this paper, three approaches of trend-lines namely linear, logarithmic, and polynomial were compared. From analysis, polynomial trend line gave the best correlation among others. The final equation is very important part when estimating more accurate values of cohesion and friction angle design purpose.

5

Regular and chaotic vibrations of a vibration-isolated hand grinder

Łuczko J., Cupiał P., Ferdek U.

Journal of Theoretical and Applied Mechanics

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2007

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Vol. 45 nr 1

61-72

EN

The paper is concerned with qualitative analysis of a non-linear model describing vibration of a vibration-isolated hand grinder. A discontinuous description of grinding forces is introduced, which accounts for the possible separation of the grinding wheel from the object during the process. Eight non-linear ordinary differential equations are obtained which describe dynamics of the system. Numerical analysis is done using methods of numerical integration and the Fast Fourier Transform. The influence of selected parameters on the character of vibration is studied and some measures are calculated which characterize the quality of the vibration isolation system.

PL

Praca dotyczy analizy jakościowej nieliniowego modelu, opisujący drgania wibroizolowanej ręcznej szlifierki. Model opisano układem ośmiu równań różniczkowych zwyczajnych drugiego rzędu. Wprowadzono nieciągły opis sił skrawania, uwzględniający możliwość chwilowego oderwania się ściernicy od obrabianego przedmiotu. Do analizy wykorzystano procedury matematycznego całkowania skojarzone z algorytmami szybkiej transformaty Fouriera. Zbadano wpływ parametrów na charakter drgań oraz wyznaczono pewne wskaźniki jakości działania zastosowanego układu wibroizolacji.

6

3D numerical investigation of tensile loaded lap bonded joint of aircraft structure

Derewońko A., Niezgoda T., Godzimirski J.

Journal of KONES

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2006

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Vol. 13, No. 3

61-68

EN

Adhesive bonding is becoming one of the most popular joining techniques in automotive and aircraft industry. The adhesively bonded joints need to be designed to minimize tensile stress. The most widely used method of an adhesive joint strength test is the lap-shear test. Single lap joints create bending loads in the adherends and tensile stress in the adhesive. The mechanism of shear deformation of the adhesive and adherend layers and separation occurring at the adherend/adhesive interface are discussed in this paper. Uniaxial tensile test of a lap bonded joint and numerical simulations were carried out. 3D numerical model of single lap bonded joint consists of three components described as separate solids. Glue contact is defined between the joined layers. This approach allows to determine and compare stress distribution along the adhesive and the adherend bondline. Experimental data are used to establish the engineering stress-strain curves for the aluminium adherends and the epoxy adhesive. Two step loadings are applied. The results of laboratory tests compare favourably with VG and Reissner closed-form solutions and numerical simulations. Non-linear analyses of a 0,03 mm thick adhesive layer show that the shear stresses along the adhesive bondline exceed stresses along the adherend line by 1% to 50%.