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21.
Ebtessam A. Essa Aya R. Elbasuony Abdelaziz E. Abdelaziz Gamal M. El Maghraby 《Drug development and industrial pharmacy》2013,39(8):1215-1223
Objectives: Enhance the dissolution rate of bicalutamide via co-crystallization with sucralose (sweetener), with the aim to develop rapidly disintegrating tablets with subsequent prompt dissolution.Significance: Bicalutamide is antiandrogenic agent for the treatment of prostate cancer but has low and variable oral bioavailability, mainly attributed to poor dissolution. Co-crystallization with benign excipients is promising for dissolution enhancement with the additive serving dual functions. The benefit will become greater if dissolution enhancement is associated with the development of orodispersible tablets which is suitable for elderly patients who are the most vulnerable for prostate cancer.Methods: Bicalutamide was dissolved in acetone in the presence of increasing molar ratios of sucralose. The solvent was evaporated while mixing to deposit crystals that were subjected to wet co-grinding until drying. The developed solids were characterized using Fourier transform infrared spectroscopy, differential thermal analysis and X-ray diffraction in addition to monitoring bicalutamide dissolution.Results: Instrumental analysis provided evidences for co-crystallization which was initiated at 1:1 molar ratio of bicalutamide to sucralose with complete co-crystallization at 1:4 molar ratio. The co-crystals provided faster bicalutamide dissolution compared with the unprocessed drug and that recrystalized from acetone in the absence of sucralose. The formulation containing bicalutamide with sucralose at 1:4 molar ratio was selected for tablet formulation into which superdisintegrants were included. The developed tablets exhibited flash disintegration with subsequent fast dissolution of bicalutamide.Conclusions: The study introduced co-crystallization of bicalutamide with sucralose as an efficient tool to enhance the dissolution rate and to develop rapidly dissolving tablets for intraoral administration. 相似文献
22.
This study concerns the fracture of rubbers. The objective is to verify the validity of the J-integral expression we proposed for such materials (Aït Hocine et al., 2002). In this expression, the parameter J is represented as a multiplicative form of a geometrical η* (or η) factor and elastic work per unit area as it has been already done in the Linear Elastic Fracture Mechanics (LEFM) (Turner, 1973). The whole problem rests in the fact that the factor η* (or η) is unknown whereas in LEFM, expressions of ηel factors are available for several kinds of specimen geometry. Thus, in this work, an experimental and a numerical analysis have been achieved and we have shown, for both the studied materials and the considered specimens, that these unknown factors could be replaced by those issued from the LEFM or from the work of Kim and Joe (1989) on rubber-like materials. The results obtained confirm the validity of our model representing a single specimen method of an experimental evaluation of the elastomers fracture energy. 相似文献
23.
Syed Zubair Ahmad Muhammad Abdul Qadir Muhammad Saeed Akbar Abdelaziz Bouras 《Wireless Personal Communications》2012,63(1):177-197
Multi-server scheduling of traffic flows over heterogeneous wireless channels affix fresh concerns of inter-packet delay variations and associated problems of out-of-sequence reception, buffer management complexity, packet drops and re-ordering overhead. In this paper, we have presented an exclusive multi-server scheduling algorithm that is specifically tuned for mobile routers equipped with multiple wireless interfaces and has attained multiple care-of-address registrations with its home agent (HA). The proposed adaptive, Self-clocked, Multi-server (ASM) scheduling algorithm is based on predetermined transmission deadlines for each arrived packet at the mobile router. The mobile flows receive desired service levels in accordance with their negotiated service rates and are only constraint by the cumulative capacity of all active links. The major challenge lies in the handling of asymmetric channels to stitch into a unified virtual channel of higher capacity with reliable service guarantees during mobility. The sorted list of transmission schedules is used to assign physical channels in increasing order of their availability. This approach specifically encapsulates the physical layer disconnections during the handovers and ensures continuous service to ongoing flows. The proposed scheduling scheme is supplemented by an analytical model and simulations to verify its efficacy. The simulation results demonstrate higher degree of reliability and scalability of service provisioning to flows during mobility. 相似文献
24.
Memdouh Chebbah Fouad Benaliouche Djalal Trache Amir Abdelaziz Ahmed Fouzi Tarchoun 《Propellants, Explosives, Pyrotechnics》2023,48(9):e202300091
Nitrocellulose is commonly used as a main ingredient in propellant formulations, but its thermal instability necessitates the employment of stabilizers as additives. In this study, the potential of four adsorbents, namely, zeolites MOR, BEA, MFI, and FAU as stabilizing agents for nitrocellulose was evaluated. Their performance was compared to that of the traditional stabilizer, DPA. The thermal stability of nitrocellulose (NC) that contains each stabilizer was assessed through VST, B&J test, and TGA analysis. The compatibility of NC with each stabilizer was also scrutinized using FTIR, heat of combustion, and DSC. The computation of the kinetic parameters for NC that contains each stabilizer was carried out using non-isothermal DSC experiments. The obtained results demonstrated that the different zeolites exhibited promising stabilizing efficiency toward NC. The zeolites revealed good compatibility with NC as well, as confirmed by FTIR and DSC analyses. This work contributes to the ongoing efforts to develop environmentally friendly stabilizers for NC. 相似文献
25.
Khalil Mokhtari Abdelhafid Elhadri Mourad Abdelaziz 《International Journal of Adaptive Control and Signal Processing》2019,33(9):1359-1373
For a class of nonlinear systems with the representation {A(x), B(x), C} and where the system parameters and dynamics are unknown, a simple adaptive synergetic controller ensuring the asymptotic convergence of the system to a desired manifold is proposed based on the technique of simple adaptive control (SAC). It is well known that the design of the synergetic control (SC) law requires a thorough knowledge of the system parameters and dynamics. Such problem obstructs the synthesis of the SC law and the designer is prompted to pass through the estimation methods, which, in turn, poses a problem of increasing the computation time of the control algorithm. To cope with this problem, a solution is proposed by modifying the original SC law to develop an SAC‐like adaptive SC law without the need of prior knowledge of the system. The stability of the proposed adaptive controller is formally proven via the Lyapunov approach. Experimental application to a quadrotor system is given to validate the theoretical results. 相似文献
26.
Taha H. S. Abdelaziz 《International journal of systems science》2017,48(13):2871-2886
In this article, the parametric solution to the pole assignment problem for multivariable linear time-invariant systems controlled by proportional-derivative (PD) state feedback is developed. The new expressions for the PD gain controllers are derived which describe the available degrees of freedom offered by PD state feedback. The freedom provided by PD state gain matrices is utilised to obtain closed-loop systems with robust and small gain matrices. Two computational algorithms are introduced, and their effectiveness is demonstrated by two simulation examples. 相似文献
27.
Karima Menani Taghreed Mohammadridha Nicolas Magdelaine Mourad Abdelaziz Claude H. Moog 《International journal of systems science》2017,48(15):3267-3278
Biological systems involving positive variables as concentrations are some examples of so-called positive systems. This is the case of the glycemia–insulinemia system considered in this paper. To cope with these physical constraints, it is shown that a positive sliding mode control (SMC) can be designed for glycemia regulation. The largest positive invariant set (PIS) is obtained for the insulinemia subsystem in open and closed loop. The existence of a positive SMC for glycemia regulation is shown here for the first time. Necessary conditions to design the sliding surface and the discontinuity gain are derived to guarantee a positive SMC for the insulin dynamics. SMC is designed to be positive everywhere in the largest closed-loop PIS of plasma insulin system. Two-stage SMC is employed; the last stage SMC2 block uses the glycemia error to design the desired insulin trajectory. Then the plasma insulin state is forced to track the reference via SMC1. The resulting desired insulin trajectory is the required virtual control input of the glycemia system to eliminate blood glucose (BG) error. The positive control is tested in silico on type-1 diabetic patients model derived from real-life clinical data. 相似文献
28.
29.
Hicham Helal Zineb Benamara Marwa Ben Arbia Abderrahim Khettou Abdelaziz Rabehi Arslane Hatem Kacha Mohammed Amrani 《International Journal of Numerical Modelling》2020,33(4):e2714
In this paper, a study of the effect of thin GaN interfacial layer (1 nm) on the electrical behavior of Au/n-GaAs structure is investigated in wide temperature range 100 to 400 K, using Silvaco-Atlas simulator. As a result, from I-V characteristics, the series resistance R s is increased with decreasing temperature for Au/GaN/n-GaAs structure, while it is remained almost constant for Au/n-GaAs structure. The saturation current I s is decreased with decreasing temperature for both structures. The ideality factor n is increased, and the barrier height is decreased when temperature decreases, with important variation for Au/GaN/n-GaAs structure. This abnormal behavior is due to the deviation of the dominant conduction mechanisms, from the thermionic emission TE current to the thermionic field emission TFE and the field emission FE. As well as, the Au/n-GaAs structure shows a homogeneous of barrier height, while it is inhomogeneous for Au/GaN/n-GaAs structure. In addition, from C-V characteristics, the potential diffusion V d and the barrier height are increased with decreasing temperature for both structures, conversely to those obtained from the TE theory. These results confirm the deviation of the TE current to the TFE and FE currents with decreasing temperature for the Au/n-GaAs and Au/GaN/n-GaAs Schottky diodes. 相似文献
30.
Yassine Kharbouch Abdelaziz Mimet Mohammed El Ganaoui Lahoucine Ouhsaine 《国际可持续能源杂志》2018,37(6):515-532
This study investigates the thermal energy potentials and economic feasibility of an air-conditioned family household-integrated phase change material (PCM) considering different climate zones in Morocco. A simulation-based optimisation was carried out in order to define the optimal design of a PCM-enhanced household envelope for thermal energy effectiveness and cost-effectiveness of predefined candidate solutions. The optimisation methodology is based on coupling Energyplus® as a dynamic simulation tool and GenOpt® as an optimisation tool. Considering the obtained optimum design strategies, a thermal energy and economic analysis are carried out to investigate PCMs’ integration feasibility in the Moroccan constructions. The results show that the PCM-integrated household envelope allows minimising the cooling/heating thermal energy demand vs. a reference household without PCM. While for the cost-effectiveness optimisation, it has been deduced that the economic feasibility is stilling insufficient under the actual PCM market conditions. The optimal design parameters results are also analysed. 相似文献