Preparation and Characterization of Carboxymethyl Cellulose with a High Degree of Substitution from Agricultural Wastes

Ibtissem Moussa,Ramzi Khiari,Ali Moussa,Mohamed Naceur Belgacem,Mohamed Farouk Mhenni 한국섬유공학회 2019 Fibers and polymers Vol.20 No.5

This paper describes the use of agricultural wastes for the preparation of carboxymethylcellulose (CMC) with ahigh degree of substitution using two methods: the classic and a microwave-assisted method. A series of CMC samples withdegrees of substitution from 0.43 to 2.83 were prepared from cellulose extracted from almond shells, almond stems, and figstems by a one-step carboxymethylation reaction. The highest degree of substitution was 2.83, which corresponded to CMCfrom fig stems when butanol was used as a solvent. This CMC was easily dissolved in water and thus would provide manyopportunities for diverse applications. The obtained CMCs were characterized using different tools. Different CMC filmswere prepared using the casting method and were characterized by the determination of their mechanical properties. Theobtained results can be considered promising; they demonstrate the potential of using cellulose derivatives for the productionof transparent and strong films.

Selective Harmonic Elimination in Multi-level Inverters with Series-Connected Transformers with Equal Power Ratings

Moussa, Mona Fouad,Dessouky, Yasser Gaber The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This study applies the selective harmonic elimination (SHE) technique to design and operate a regulated AC/DC/AC power supply suitable for maritime military applications and underground trains. The input is a single 50/60 Hz AC voltage, and the output is a 400 Hz regulated voltage. The switching angles for a multi-level inverter and transformer turns ratio are determined to operate with special connected transformers with equal power ratings and produce an almost sinusoidal current. As a result of its capability of directly controlling harmonics, the SHE technique is applicable to apparatus with congenital immunity to specific harmonics, such as series-connected transformers, which are specially designed to equally share the total load power. In the present work, a single-phase 50/60 Hz input source is rectified via a semi-controlled bridge rectifier to control DC voltage levels and thereby regulate the output load voltage at a constant level. The DC-rectified voltage then supplies six single-phase quazi-square H-bridge inverters, each of which supplies the primary of a single-phase transformer. The secondaries of the six transformers are connected in series. Through off-line calculation, the switching angles of the six inverters and the turns ratios of the six transformers are designed to ensure equal power distribution for the transformers. The SHE technique is also employed to eliminate the higher-order harmonics of the output voltage. A digital implementation is carried out to determine the switching angles. Theoretical results are demonstrated, and a scaled-down experimental 600 VA prototype is built to verify the validity of the proposed system.

Thermomechanical analysis of antisymmetric laminated reinforced composite plates using a new four variable trigonometric refined plate theory

Moussa Abualnour,Abdelbaki Chikh,Habib Hebali,Abdelhakim Kaci,Abdeldjebbar Tounsi,Abdelmoumen Anis Bousahla,Abdelouahed Tounsi 사단법인 한국계산역학회 2019 Computers and Concrete, An International Journal Vol.24 No.6

The thermo-mechanical bending behavior of the antisymmetric cross-ply laminates is examined using a new simple four variable trigonometric plate theory. The proposed theory utilizes a novel displacement field which introduces undetermined integral terms and needs only four variables. The validity of the present model is proved by comparison with solutions available in the literature.

Principal Components Analysis based Fault Detection and Isolation for Electronic Throttle Control System

Moussa Hamadache,Dongik Lee 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

In this paper, a Principal Component Analysis (PCA) based Fault Detection and Isolation (FDI) method for nonlinear Electronic Throttle Control (ETC) system is presented. The proposed method introduces a novel configuration of PCA bases by computing the absolute value of weights. The fault can be detected if the Sum Square Error (SSE) distance exceeds its pre-defined threshold and the isolation of the detected fault is done under the minimum of the SSE distance. The PCA model is used to detect (offline and/or online) failure in the ETC from the old Normal Operation Condition (NOC) as well as to diagnose the cause of the failure. A set of faults with armature resistance, armature inductance are evaluated to demonstrate the performance and effectiveness of the proposed method.

Principal Component Analysis Based Signal-to-noise Ratio Improvement for Inchoate Faulty Signals: Application to Ball Bearing Fault Detection

Moussa Hamadache,이동익 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.2

This paper addresses the development of an algorithm that can improve the signal-to-noise ratio (SNR)in inchoate faulty signals. The removal of noise and preservation of fault information components cannot be easilyachieved. Many techniques for SNR improvement in healthy signals rely on frequency bands. Such techniqueshave been proven to be efficient in improving the SRN by filtering out frequency bands (FoFBs). However, thesetechniques cannot reduce noise and preserve fault information when dealing with inchoate faulty signals. Thus, afeature extraction technique based on statistical parameters, which are free from Gaussian noise, is proposed in thispaper. The proposed signal subspace-based approach for SNR improvement in inchoate faulty signals is based on amodified principal component analysis (PCA), in which the optimal subspace is selected via a cumulative percentof variance (CPV) criterion and the test statistic condition of the true information loss, which has the tendencyto alleviate the impact of Gaussian and non-Gaussian noise and provides useful time domain analysis for nonstationarysignals such as vibration, in which spectral contents vary with respect to time. Furthermore, the modifiedPCA algorithm is combined with a low-pass filter (LPF) to achieve an optimum balance between noise reductionefficiency and the conservation of inchoate fault information. The proposed PCA-LPF algorithm is compared withdifferent filters under different noise levels to find the most efficient approach in terms of optimizing the trade-offbetween noise reduction efficiency and precision of inchoate fault information conservation, with the final goalof improving the fault detection capability. Further, the performance of the proposed PCA-LPF algorithm wasdemonstrated with an experimental study on vibration-based ball bearing fault detection.

Buckling behavior of a single-layered graphene sheet resting on viscoelastic medium via nonlocal four-unknown integral model

Moussa Bellal,Habib Hebali,Houari Heireche,Abdelmoumen Anis Bousahla,Abdeldjebbar Tounsi,Fouad Bourada,S.R. Mahmoud,E.A. Adda Bedia,Abdelouahed Tounsi 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.34 No.5

In the present work, the buckling behavior of a single-layered graphene sheet (SLGS) embedded in visco-Pasternak’s medium is studied using nonlocal four-unknown integral model. This model has a displacement field with integral terms which includes the effect of transverse shear deformation without using shear correction factors. The visco-Pasternak’s medium is introduced by considering the damping effect to the classical foundation model which modeled by the linear Winkler’s coefficient and Pasternak’s (shear) foundation coefficient. The SLGS under consideration is subjected to compressive in- plane edge loads per unit length. The influences of many parameters such as nonlocal parameter, geometric ratio, the visco-Pasternak’s coefficients, damping parameter, and mode numbers on the buckling response of the SLGSs are studied and discussed.

Removal of Methylene Blue (MB) in Aqueous Solution by Economic Adsorbent Derived from Apricot Stone Activated Carbon(ASAC)

Moussa Abbas,Mohamed Trari 한국섬유공학회 2020 Fibers and polymers Vol.21 No.4

Quantitative adsorption kinetic and equilibrium parameters for methylene blue (MB) used in the textile industryfrom aqueous solutions were reported in this study using pHPZC and UV-visible absorption spectroscopy. The effects ofadsorbent dosage (1-10 g/l), agitation speed (100-1200 rpm), particule size (63 μm to 2 mm), initial dye concentration (4-15 mg/l), contact time, pH (2-14), and temperature (298-338 K) were determined to find the optimal conditions foradsorption. The FTIR spectroscopy is used to get information on interactions between the adsorbent and MB. The mechanismof adsorption of MB dyeing onto Apricot Stone Activated Carbon (ASAC) was investigated using the pseudo first-order,pseudo second-order kinetic, Elovich and intraparticles diffusion models. The adsorption isotherms of MB onto ASAC aredetermined and correlated with common isotherm equations. The smaller RMSE value obtained for the Langmuir modelindicates the better curve-fitting and the monolayer adsorption capacity of MB is found to be 46.03 mg/g at 25 oC and88.50 mg/g at 70 oC and pH 10. The evaluation of thermodynamics parameters such as the negative free energy ΔGo(+2.70025 to -1.76666 kJ/mol) and positive enthalpy change ΔHo (28.87613 kJ/mol) indicated a spontaneous andendothermic nature of the reaction with chemisorption process. This study in tiny batch gave rise to encouraging results, andwe wish to achieve the adsorption tests in column mode under the real conditions applicable to the treatment of industrialeffluents. The present investigation showed that ASAC is potentially a useful adsorbent for the heavy metals and dyes.

Some Thiosemicarbazide Derivatives as Corrosion Inhibitors for Aluminium in Sodium Hydroxide Solution

Moussa, M.N.,Fouda, A.S.,Taha, F.I.,Elnenaa, A. Korean Chemical Society 1988 Bulletin of the Korean Chemical Society Vol.9 No.4

The effect of some thiosemicarbazide derivatives on corrosion of aluminium in 2M sodium hydroxide has been studied using thermometric, weight loss and hydrogen evolution techniques. The rate of the corrosion depends on the nature of the inhibitor and its concentration, heated of hydrogenation, mode of interaction with the metal surface and formation of metallic complexes. The compounds are weakly adsorbed on the surface of aluminium and form a monolayer of the adsorbate. Values of the Arrhenius activation energies indicate agreement with those obtained for an activation controlled process.

Robust Adaptive Global Time-varying Sliding-mode Control for Finitetime Tracker Design of Quadrotor Drone Subjected to Gaussian Random Parametric Uncertainties and Disturbances

Moussa Labbadi,Mohamed Cherkaoui 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.6

The quadrotor has many potential applications such as infrastructure predictive maintenance in mining tunnels of the railway. In order to navigate through those environments by using the quadrotor drone, there are many challenges such as aerodynamics disturbances, parametric uncertainties, and noise measurements. A robust adaptive global time-varying sliding-mode controller (RAGTVSMC) is proposed to address the quadrotor path in the presence of the random disturbances and uncertainties. In order to eliminate the reaching phase and reduce the initial control effort, a novel time-varying sliding mode (TVSM) surface is presented for the quadrotor system. Moreover, the TVSM surface is designed to meet the impact time requirement with a global sliding mode. Adaptive laws are developed to address the upper bound of the additives disturbances on the quadrotor dynamics using only the error position and velocity. The convergence with specific time is assured and the quadrotor stability is proved according to Lyapunov’s theory. Finally, to demonstrate the effectiveness of the proposed controller in this work,simulations are conducted.

Comparative Study on Bone Marrow-Versus Adipose-Derived Stem Cells on Regeneration and Re-Innervation of Skeletal Muscle Injury in Wistar Rats

Moussa Manal H.,Hamam Ghada G.,Abd Elaziz Asmaa E.,Rahoma Marwa A.,Abd El Samad Abeer A.,El-Waseef Dalia A. A.,Hegazy Mohamed A. 한국조직공학과 재생의학회 2020 조직공학과 재생의학 Vol.17 No.6

Background: Skeletal muscle injuries are frequent clinical challenges due to associated fibrosis and disability. Regenerative medicine is an emerging promising strategy for such cases. The aim of this study was to compare between the effects of bone marrow-mesenchymal stem cells (BM-MSCs) versus adipose tissue stromal cells (ADSCs) on regeneration and re-innervation of skeletal muscle laceration injury in Wistar rats at different time intervals. Methods: Six young male rats were used as a source of allogenic MSCs. Eighty-four adult female rats were divided into: Group I (control), Group II (Untreated Laceration): right gluteal muscle was lacerated and left for spontaneous healing, Group III (BM-MSCs): right gluteal muscle was lacerated with concomitant local intramuscular injection of 1 × 106 BM-MSCs in the lacerated muscle, Group IV (ADSCs): right gluteal muscle was lacerated with concomitant local intramuscular injection of 1 × 106 ADSCs in lacerated muscle. Rats were sacrificed after one, two and eight weeks. Muscles were processed to prepare sections stained with H&E, Mallory’s trichrome and immune-histochemical staining (neurofilament light chain). Results: A significant increase in collagen fibers and failure of re-innervation were noticed in untreated laceration group. BM-MSCs-treated groups showed regeneration of muscle fibers but with increased collagen fibers. Meanwhile, ADSCs showed better regenerative effects evidenced by significant increase in the number of myotubes and significant decrease in collagen deposition. Re-innervation was noticed in MSCs-injected muscles after 8 weeks of laceration. Conclusion: Both BM-MSCs and ADSCs improved regeneration of skeletal muscle laceration injury at short- and long-term durations. However, fibrosis was less in ADSCs-treated rats. Effective re-innervation of injured muscles occurred only at the long-term duration.