New Chaotic Sunfl ower Optimization Algorithm for Optimal Tuning of Power System Stabilizers

Badr M. Alshammar,Tawfik Guesmi 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.5

Purpose The problem of stability is generally caused by insuffi cient damping of electromechanical oscillations (EMOs). Power system stabilizers (PSSs) are the most advised and effi cient devices to increase the system damping and enhance the dynamic characteristics of power networks during abnormal conditions. Unfortunately, the performance of the PSS controller is mostly dependent on the parameters of the lead-lag compensator. Within this context, this study presents a new chaoticbased sunfl ower optimization algorithm with local search (CSFO-LS) for optimum design of PSS controllers. Methodology In the proposed algorithm symbolized by CSFO-LS, the random parameters of the original SFO are substituted by chaotic sequences to avoid premature convergence at local optima and improve the accuracy of the optimum solution. Firstly, the CSFO-LS is tested and evaluated on various benchmark functions with diff erent characteristics such as multimodality, separability and regularity. Then, it is applied for selecting the optimum parameters of the PSS controllers. These parameters are tuned in order to shift all electromechanical modes in a pre-specifi ed zone in the left side of the s -plan. Results Simulation results based on eight benchmark functions show that CSFO-LS outperforms all the algorithms used for comparison. Moreover, to demonstrate the applicability and performance of the proposed method for providing good damping of low frequency oscillations, a standard power system test under various operating conditions and severe fault is used. Obtained results are compared with those obtained using the original SFO and other recent optimization techniques. Originality In this study, an improved version of the SFO is proposed for providing optimum EMOs damping. All EMOs have to be shifted as much as possible to the left side of the s -plan instead of shifting them to a fi xed zone. To our best knowledge, this technique is not suggested or used for any power system problem.

Long-standing chin-augmenting costochondral graft creating a diagnostic challenge: A case report and literature review

Badr, Fatma Fayez,Mintline, Mark,Ruprecht, Axel,Cohen, Donald,Blumberg, Barton R.,Nair, Madhu K. Korean Academy of Oral and Maxillofacial Radiology 2016 Imaging Science in Dentistry Vol.46 No.4

To our knowledge, the imaging features of costochondral grafts (CCGs) on cone-beam computed tomography (CBCT) have not been documented in the literature. We present the case of a CCG in the facial soft tissue to the anterior mandible, with changes mimicking a cartilaginous neoplasm. This is the first report to describe the CBCT imaging features of a long-standing graft in the anterior mandible. Implants or grafts may be incidental findings on radiographic images made for unrelated purposes. Although most are well-defined and radiographically homogeneous, being of relatively inert non-biological material, immune reactions to some grafts may stimulate alterations in the appearance of surrounding tissues. Biological implants may undergo growth and differentiation, causing their appearance to mimic neoplastic lesions. We present the case of a cosmetic autogenous CCG that posed a diagnostic challenge both radiographically and histopathologically.

Synthesis and Characterization of Polymer and Polymer Complex with Some Transition Metal Ions

Badr, S.K.,Mohamed, T.Y. Korean Chemical Society 2010 대한화학회지 Vol.54 No.1

Polyamide derived from azo compound of o-amino phenol coupled with acetyl acetone, maleic anhydride acid and p-phenylene diamine were prepared. The prepared polyamide (PA) was refluxed with metal salts of transition metal ions include, $Co^{+2},\;Cr^{+2},\;Ni^{+2},\;Cu^{+2},\;Zn^{+2},\;Cd^{+2}$ and $Fe^{+3}$ in dimethyl formamide (DMF) in different molar ratios. These complexes were characterized and identified by elemental and thermal analysis, IR, 1H NMR spectra. The data showed that PA ligand coordinates with metal ions in abidentate manner through donating N=N and O-H groups. The metal ions are surrounded by coordinated water molecules and anions to establish the geometrical structure of the complexes. The thermal analysis degradation at different temperatures explained the weight loss of hydrated water and the decompositions of complexes until a constant weight loss of metal oxides is obtained. p-페닐렌 디아민과 maleic anhydride, 아세틸 아세톤과 커플된 O-아미노 페놀의 아조화합물으로 부터 폴리이미드가 만들어졌다. 합성된 폴리이미드(PA)는 DMF용매 속에 다른 몰비율로 녹아있는 $Co^{+2},\;Cr^{+2},\;Ni^{+2},\;Cu^{+2},\;Zn^{+2},\;Cd^{+2}$ and $Fe^{+3}$ 를 포함하는 전이금속이온들의 금속염들과 함께 환류되었다. 이 complex들은 원소분석과 열분석, IR, $^1H$ NMR으로 구조분석, 특성 연구되었다.

Efficacy of dental local anesthetics: A review

Badr, Nelly,Aps, Johan The Korean Dental Society of Anesthsiology 2018 Journal of Dental Anesthesia and Pain Medicine Vol.18 No.6

The objective of this review was to investigate the efficacy of dental local anesthetics, as it is well known among clinicians that local anesthesia may be challenging in some circumstances. Therefore, the focus of this review was on the efficacy of the products used in dental local anesthesia. In a Pubmed database literature search conducted, a total of 8646 articles were found to be related to dental local anesthetics. After having applied the inclusion criteria (human research, performed in the last 10 years, written in English language, and focus on dental local anesthetics) and having assessed the quality of the papers, 30 were deemed eligible for inclusion in this review. The conclusion of this review is that none of the dental local anesthetic amides provide 100% anesthesia. The problem appears to be more pronounced when mandibular teeth are attempted to be anaesthetized and especially if there is irreversible pulpitis involved. The authors conclude that this finding suggest exploration of more efficient techniques to administer dental local anesthesia, especially in the mandible, to establish a 100% efficacy, is needed.

Blocking Toll-like receptor 9 attenuates bleomycin-induced pulmonary injury

Badr Alzahrani,Mohamed M. S. Gaballa,Ahmed A. Tantawy,Maha A. Moussa,Salma A. Shoulah,Said M. Elshafae 대한병리학회 2022 Journal of Pathology and Translational Medicine Vol.56 No.2

Background: Acute respiratory distress syndrome (ARDS) is one of the most common complications in coronavirus disease 2019 patients suffering from acute lung injury (ALI). In ARDS, marked distortion of pulmonary architecture has been reported. The pulmonary lesions in ARDS include hemodynamic derangements (such as alveolar edema and hemorrhage), vascular and bronchiolar damage, interstitial inflammatory cellular aggregations, and eventually fibrosis. Bleomycin induces ARDS-representative pulmonary damage in mice and rats; therefore, we used bleomycin model mice in our study. Recently, Toll-like receptor 9 (TLR9) was implicated in the development of ARDS and ALI.Methods: In this study, we evaluated the efficiency of a TLR9 blocker (ODN2088) on bleomycin-induced pulmonary damage. We measured the apoptosis rate, inflammatory reaction, and fibroplasia in bleomycin- and bleomycin + ODN2088-treated mice.Results: Our results showed a significant amelioration in bleomycin-induced damage to pulmonary architecture following ODN2088 treatment. A marked decrease in pulmonary epithelial and endothelial apoptosis rate as measured by cleaved caspase-3 expression, inflammatory reaction as indicated by tumor necrosis factor α expression, and pulmonary fibrosis as demonstrated by Van Gieson staining and α-smooth muscle actin immunohistochemistry were observed following ODN2088 treatment.Conclusions: All these findings indicate that blocking downstream TLR9 signaling could be beneficial in prevention or mitigation of ARDS through hemodynamic derangements, inflammation, apoptosis, and fibrosis.

Modifying the aggregated wind farm model with a controller

Badr, Mohammed. A.,Atallah, Ahmed. M.,Bayoumi, Mona A. Techno-Press 2015 Advances in energy research Vol.3 No.3

A large wind farm can be simplified by the aggregated wind farm models for load flow, steady and transient stability studies. When a fault (such as a short circuit) happens in a large wind farm, some of wind turbines trip while others do not. This paper is to design a controller to modify the aggregated wind farm model in the case of one or more unit removed or added from the complete model. This is without stopping the simulation process during performing the steady state and transient analysis of the whole system. This controller can modulate the status of the wind turbines in the aggregated model in a given farm according to any change in this farm. By this controller, we save effort and time to change the status of wind turbines in the aggregated model. The proposed wind farm is composed of some smaller farms of permanent magnet synchronous generators (PMSGs) and others of squirrel cage induction generators (SCIGs).

A MIXED INTEGRAL EQUATION IN THE QUASI-STATIC DISPLACEMENT PROBLEM

Badr, Abdallah A. 한국전산응용수학회 2000 Journal of applied mathematics & informatics Vol.7 No.2

In this work, we solve the Fredholm-Volterra integral equation(FVIE) when the kernel takes a potential function form under given conditions. we represent this kernel in the Weber-sonin integral form.

Development of Rectangular Broad-crested Weirs for Flow Characteristics and Discharge Measurement

Kiumars Badr,Dariush Mowla 대한토목학회 2015 KSCE JOURNAL OF CIVIL ENGINEERING Vol.19 No.1

One of the important problems which designers and engineers are faced with is proper measurement of water flow rates in openchannels and rivers. To solve this problem, the water discharge to be precisely measured in water conveyance systems such as offtakes and distribution ditches. The common procedure to meet this requirement is achieved by using water-measuring structures suchas flumes, orifices, weirs and current meters. Among the mentioned structure, engineers prefers the weirs because of their simplestructure and economical features. The broad-crested rectangular weirs are very common which are widely used in water ways andcanals. In this study, the effect of steeping in the upstream side of rectangular broad-crested weirs over discharge coefficient and flowcharacteristics is investigated. Five weirs with 15, 30, 45, 60 and 90 weir angles were developed and flow discharge coefficient,negative velocity over the weir crest edge and water surface profiles along the weir crest evaluated in laboratory hydraulic flume. Theobtained results showed by decreasing the slope of the upstream side, discharge efficiency and the discharge capacity of the weir areincreased subsequently. Consideration of experimental data it is obvious that by using the proposed weir with slope of 15 degree incomparison with standard weir, the efficiency is increased up to 19.17%. It is noteworthy that by reducing the slope, return current onthe crest is not observed.

Camouflage treatment of posterior bite collapse in a patient with skeletal asymmetry by using posterior maxillary segmental osteotomy

Haitham Badr,Soo-Yeon Lee,Hong-Sik Park,Joo-Young Ohe,Yoon-Goo Kang,Hyo-Won Ahn 대한치과교정학회 2020 대한치과교정학회지 Vol.50 No.4

Orthodontic treatment of posterior bite collapse due to early loss of molars and the consequent drift of adjacent teeth is complicated. When the posterior bite collapse occurs in patients with facial asymmetry, both transverse and vertical compensation are necessary for camouflage orthodontic treatment. In such cases, posterior maxillary segmental osteotomy (PMSO) can be an effective alternative procedure that simplifies the orthodontic treatment and shows long-term stability through dental compensation within the alveolar bone housing. This case report aimed to describe the orthodontic treatment of maxillary occlusal plane canting caused by severely extruded maxillary teeth in a patient with skeletal facial asymmetry that was corrected with PMSO along with protraction of the lower second molar to replace the space of the extracted first molar. The treatment duration was 18 months, and stable results were obtained after 2 years of retention.

Preparation and Characterization of Poly(methyl methacrylate) Particles by Combined Dispersion and Emulsion Polymerization

Ibrahim Badr,Hadjira Lahmar,Chariya Kaewsaneha,Salima Saidi-Besbes,Abdelhamid Elaissari 한국고분자학회 2018 Macromolecular Research Vol.26 No.9

Monodispersed poly(methyl methacrylate) (PMMA) nanoparticles were synthesized by combined dispersion and emulsion polymerization, using aqueous alcohol (methanol/water) as the dispersion medium. The influence of the dispersion medium ratio, stabilizer concentration, and initiator type and concentration on the colloidal stability, particle size, size distribution, and %conversion, was investigated. Submicron PMMA particles with a size of approximately 760 nm with a narrow size distribution, high conversion (91%) and good stability throughout the polymerization were obtained using a 50/50 methanol/water ratio, 1wt% 2,2’-azobisisobutyronitrile (based on monomer), and 1wt% polyvinylpyrrolidone (based on medium). With increasing the polarity of the dispersion medium (30/70 methanol/water ratio), the size and conversion of PMMA particles decreased to 345 nm and 72%, respectively.