Initial fault time estimation of rolling element bearing by backtracking strategy, improved VMD and infogram

Abdalla Babiker,Changfeng Yan,Qiang Li,Jiadong Meng,Lixiao Wu 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.2

Rolling bearing failure is widely regarded as a failure form of industrial machines. Owing to the poor operating circumstance with the stochastic contact between rolling elements, the performance of the bearing will deteriorate over time and cause a cascade breakdown in the mechanical system. Early fault detection has been found to be an effective strategy to avoid economic loss. Therefore, an integration method for fault diagnosis that combines backtracking strategy, improved variational mode decomposition (VMD), and infogram is proposed to tackle the challenge of the early feature extraction from the heavy noisy non-stationary signal. The backtracking strategy is adopted to track the data sample points earlier than the fault threshold determined based on the kurtosis index. The optimum parameters α and K of VMD are acquired through the particle swarm optimization (PSO) algorithm. In this way, the more accurate intrinsic mode functions (IMFs) can be gained by the improved VMD. The optimum IMFs are acquired according to the maximum values of kurtosis and correlation coefficients, and these IMFs can be reconstructed into the noise reduction signal. Since envelope analysis requires the selection of the appropriate central frequency and bandwidth, infogram is utilized to select the values of them. A simulated case is applied to demonstrate the validation of the proposed method. And to further illustrate its practicality, it is employed to perform early fault diagnosis for an experimental case. According to the diagnosis results, the proposed method has conspicuous superiority over the other existing technologies for estimating incipient fault time of the bearing.

Design of a Mixed-Spectrum Reactor With Improved Proliferation Resistance for Long-Lived Applications

Abdalla Abou-Jaoude,Anna Erickson,Nicolas Stauff 한국방사성폐기물학회 2018 방사성폐기물학회지 Vol.16 No.3

Long-lived Small Modular Reactors are being promoted as an innovative way of catering to emerging markets and isolated regions. They can be operated continuously for decades without requiring additional fuel. A novel configuration of long-lived reactor core employs a mixed neutron spectrum, providing an improvement in nonproliferation metrics and in safety characteristics. Starting with a base sodium reactor design, moderating material is inserted in outer core assemblies to modify the fast spectrum. The assemblies are shuffled once during core lifetime to ensure that every fuel rod is exposed to the thermalized spectrum. The Mixed Spectrum Reactor is able to maintain a core lifetime over two decades while ensuring the plutonium it breeds is below the weapon-grade limit at the fuel discharge. The main drawbacks of the design are higher front-end fuel cycle costs and a 58% increase in core volume, although it is alleviated to some extent by a 48% higher power output.

A geometrically nonlinear thick plate bending element based on mixed formulation and discrete collocation constraints

Abdalla, J.A.,Ibrahim, A.K. Techno-Press 2007 Structural Engineering and Mechanics, An Int'l Jou Vol.26 No.6

In recent years there are many plate bending elements that emerged for solving both thin and thick plates. The main features of these elements are that they are based on mix formulation interpolation with discrete collocation constraints. These elements passed the patch test for mix formulation and performed well for linear analysis of thin and thick plates. In this paper a member of this family of elements, namely, the Discrete Reissner-Mindlin (DRM) is further extended and developed to analyze both thin and thick plates with geometric nonlinearity. The Von K$\acute{a}$rm$\acute{a}$n's large displacement plate theory based on Lagrangian coordinate system is used. The Hu-Washizu variational principle is employed to formulate the stiffness matrix of the geometrically Nonlinear Discrete Reissner-Mindlin (NDRM). An iterative-incremental procedure is implemented to solve the nonlinear equations. The element is then tested for plates with simply supported and clamped edges under uniformly distributed transverse loads. The results obtained using the geometrically NDRM element is then compared with the results of available analytical solutions. It has been observed that the NDRM results agreed well with the analytical solutions results. Therefore, it is concluded that the NDRM element is both reliable and efficient in analyzing thin and thick plates with geometric non-linearity.

The Modification of Rice Husk Derived Bio Char with AlCl3 for Removal of Fluoride from Groundwater

( Abdalla Mussa Juma. Prof ),( Seong-jik Park ) 한국농공학회 2020 한국농공학회 학술대회초록집 Vol.2020 No.-

The problem of high amount of fluoride in groundwater is commonly in the worldwide. Many researchers and scholars with different techniques was tried dealing with that problem so as to solve it. Different parameters affecting efficiency of fluoride removal such as adsorbent dose, the time of contact, temperatures conditions, fluoride concentration, pH solution and ions concentrations were considered. Groundwater was used to test the performance of the adsorbent under the optimum conditions. Equilibrium data are well expressed by Freundlich isotherm models and Langmuir, so as to Compared to the adsorption characteristics of fluoride on Aluminum chloride. The pseudo first order and pseudo second order were also applied in comparison. While the pseudo second-order model is found to be more suitable than the pseudo first-order to the fluorides adsorption description. It is observed that, under the optimum conditions the use of aluminum chloride with modified rice husk bio char are maximum in fluoride removal, which indicated that aluminum chloride-modified bio char can be used efficiently as adsorbents for the fluoride removal. The aluminum chloride-modified bio char derived from rice husk were used to treat the fluoride obtained from groundwater.

Effect of Diameters and Alkali Treatment on the Tensile Properties of Date Palm Fiber Reinforced Epoxy Composites

Abdalla Abdal-hay,임재규,Ngakan Putu Gede Suardana,정도연,최광석 한국정밀공학회 2012 International Journal of Precision Engineering and Vol.13 No.7

Natural fibers as reinforced polymer composites have recently been the center of attention among researchers. Surface modifications and variations in the fiber diameters are major factors that influence the fiber adhesion performance inside the matrix. Experiments have been performed to further the development of natural fiber reinforced polymers as a replacement for glass fibers. In the present research, date palm fibers (DPFs) with three different size ranges of diameters (800-600, 600-400, and 400-200 μm) and the influence of alkali treatment on their characteristics have been investigated. Morphology observations (SEM), EDS density mapping (quantitative elemental analysis), X-RD, and FTIR spectroscopy of treated and untreated fibers were carried out. In addition, the tensile properties of a single fiber and composites consisting of fibers/epoxy with discontinuous random oriented short fibers both with and without chemical modification were studied. The results showed that DPFs are amenable to chemical modification particularly in the fine fiber case. It was found that the ultimate tensile strength and percentage elongation of a single fiber after alkali treatment increased by 57% and 24.7 %,respectively. Because alkali treatment of the DPFs was able to provide a good adhesion within the matrix, the tensile strength, elastic modulus and the fiber-matrix interaction of the composite were improved. Collectively, the addition of the proposed DPFs may open a new avenue for the exploitation of this natural cheap material to produce a green composite.

EMBEDDING RIEMANNIAN MANIFOLDS VIA THEIR EIGENFUNCTIONS AND THEIR HEAT KERNEL

Abdalla, Hiba Korean Mathematical Society 2012 대한수학회보 Vol.49 No.5

In this paper, we give a generalization of the embeddings of Riemannian manifolds via their heat kernel and via a finite number of eigenfunctions. More precisely, we embed a family of Riemannian manifolds endowed with a time-dependent metric analytic in time into a Hilbert space via a finite number of eigenfunctions of the corresponding Laplacian. If furthermore the volume form on the manifold is constant with time, then we can construct an embedding with a complete eigenfunctions basis.

Performance Evaluation for a Unicast Vehicular Delay Tolerant Routing Protocol Networks

Abdalla, Ahmed Mohamed International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.2

Vehicular Ad hoc Networks are considered as special kind of Mobile Ad Hoc Networks. VANETs are a new emerging recently developed, advanced technology that allows a wide set of applications related to providing more safety on roads, more convenience for passengers, self-driven vehicles, and intelligent transportation systems (ITS). Delay Tolerant Networks (DTN) are networks that allow communication in the event of connection problems, such as delays, intermittent connections, high error rates, and so on. Moreover, these are used in areas that may not have end-to-end connectivity. The expansion from DTN to VANET resulted in Vehicle Delay Tolerant Networks (VDTN). In this approach, a vehicle stores and carries a message in its buffer, and when the opportunity arises, it forwards the message to another node. Carry-store-forward mechanisms, packets in VDTNs can be delivered to the destination without clear connection between the transmitter and the receiver. The primary goals of routing protocols in VDTNs is to maximize the probability of delivery ratio to the destination node, while minimizing the total end-to-end delay. DTNs are used in a variety of operating environments, including those that are subject to failures and interruptions, and those with high delay, such as vehicle ad hoc networks (VANETs). This paper discusses DTN routing protocols belonging to unicast delay tolerant position based. The comparison was implemented using the NS2 simulator. Simulation of the three DTN routing protocols GeOpps, GeoSpray, and MaxProp is recorded, and the results are presented.

The effect of immediate neoadjuvant electromotive instillation of mitomycin C with Bacillus Calmette–Guérin versus BCG alone in non-muscle-invasive bladder cancer: A randomized controlled trial

Abdalla El Azab,Ahmed Abd Elbary,Aly El Faqeh M. Okasha,Hatem Aboulkassem,Ashraf Saad Zaghloul,Riham Mohamed Karkeet,Ibrahim Abdelrahman 대한비뇨의학회 2023 Investigative and Clinical Urology Vol.64 No.6

Purpose: The clinical effect of neoadjuvant intravesical instillation of chemotherapy immediately before transurethral resection of bladder tumors (TURBT) has been a subject of recent research. The aim of this study was to assess the effect of immediate neoadjuvant electromotive instillation of mitomycin C before transurethral resection for patients with non-muscle-invasive urothelial bladder cancer. Materials and Methods: Our study was a randomized clinical trial carried out on 50 patients diagnosed with non-muscle-invasive urothelial bladder cancer. Patients were classified into two groups: Group I consisted of 25 patients who received neoadjuvant electromotive drug administration of mitomycin C before TURBT and intravesical bacille Calmette–Guerin (BCG) per week for 6 weeks; Group II consisted of 25 patients who were treated with TURBT followed by intravesical BCG per week for 6 weeks alone (standard of care). Patients were followed up at 3, 6, 12, and 18 months by cystoscopy. Results: Patients who received neoadjuvant electromotive drug administration of mitomycin C before TURBT in combination with BCG had a low recurrence rate compared with those who received BCG alone (12.0% vs. 48.0%, respectively; p=0.012) and a longer disease-free interval (88.0% vs. 52.0%, respectively; p=0.012). Four patients developed progression to muscle-invasive disease (16.0%) in the BCG alone group. However, this difference was not statistically significant (p=0.516). Regarding adverse effects, there were no statistically significant differences between the groups. Conclusions: Neoadjuvant intravesical electromotive drug administration of mitomycin C before TURBT is safe; reduces recurrence rates and enhances the disease-free interval compared with TURBT followed by BCG alone.

Anthraquinones with Antibacterial Activities from Crucianella maritima L. Growing in Egypt

Abdalla M. El-Lakany,Maha A. Aboul-Ela,Maged S. Abdel-Kader,Jihan M. Badr,Nawal N. Sabri,Yousry Goher 한국생약학회 2004 Natural Product Sciences Vol.10 No.2

From the extracts of Crucianella maritima L. (Rubiaceae), five new anthraquinones namely; 1-hydroxy- 2-methyl-6-methoxy anthraquinone, 6-methoxy-2-methyl quinizarin, 6-methyl-anthragallol-2,3-dimethyl ether, 6-methyl-anthragallol-2-methyl ether, and 1-hydroxy-2-carbomethoxyanthraquinone were isolated and identified. In addition, deacetyl asperulosidic acid 6'-glucoside sodium salt, a new iridoid diglucoside, along with twelve known anthraquinones, three flavonols, three sterols, and one triterpene were also isolated and identified for the first time from this plant. Their chemical structures were established by physical, chemical and spectroscopic data, including UV, MS, ID- and 2D-NMR analyses. The antimicrobial, cytotoxic activities and a preliminary clinical trial of the crude extracts and some isolates are also presented. Chemotaxonomical aspects are briefly discussed.

Chlorosmaridione; A Novel Chlorinated Diterpene Quinone Methide from Rosemarinus officinalis L.

Abdalla M. El-Lakany 한국생약학회 2004 Natural Product Sciences Vol.10 No.2

A novel chlorinated diterpene quinone methide; chlorosmaridione (7-chloro-11-hydroxy-abeita-7,9(11),13-triene-6,12-dione) was isolated from petroleum ether extract of the stems of Rosemarinus officinalis L. growing in Egypt. In addition, β-sitosterol, stigmasterol, lupeol acetate, α-amyrin, β-amyrin, lupeol, acetyloleanolic acid, acetylursolic acid taxodione, horminone, and cryptotanshinone were also identified. Chemical structures of the isolated compounds have been elucidated on the bases of physical, chemical, and spectral data including IR, UV, MS, 1Dand 2D-NMR spectra.