Computer Modeling, Characterization, and Applications of Gallium Arsenide Gunn Diodes in Radiation Environments

Wafaa Abd El-Basit,Safaa Mohamed El-Ghanam,Ashraf Mosleh Abdel-Maksood,Sanaa Abd El-Tawab Kamh,Fouad Abd El-Moniem Saad Soliman 한국원자력학회 2016 Nuclear Engineering and Technology Vol.48 No.5

The present paper reports on a trial to shed further light on the characterization, applications, and operation of radar speed guns or Gunn diodes on different radiation environments of neutron or g fields. To this end, theoretical and experimental investigations of microwave oscillating system for outer-space applications were carried out. Radiation effects on the transient parameters and electrical properties of the proposed devices have been studied in detail with the application of computer programming. Also, the oscillation parameters, power characteristics, and bias current were plotted under the influence of different g and neutron irradiation levels. Finally, shelf or oven annealing processes were shown to be satisfactory techniques to recover the initial characteristics of the irradiated devices.

Non-Gaussian approach for equivalent static wind loads from wind tunnel measurements

Wafaa Kassir,Christian Soize,Jean-Vivien Heck,Fabrice De Oliveira 한국풍공학회 2017 Wind and Structures, An International Journal (WAS Vol.25 No.6

A novel probabilistic approach is presented for estimating the equivalent static wind loads that produce a static response of the structure, which is ”equivalent” in a probabilistic sense, to the extreme dynamic responses due to the unsteady pressure random field induced by the wind. This approach has especially been developed for complex structures (such as stadium roofs) for which the unsteady pressure field is measured in a boundary layer wind tunnel with a turbulent incident flow. The proposed method deals with the non-Gaussian nature of the unsteady pressure random field and presents a model that yields a good representation of both the quasi-static part and the dynamical part of the structural responses. The proposed approach is experimentally validated with a relatively simple application and is then applied to a stadium roof structure for which experimental measurements of unsteady pressures have been performed in boundary layer wind tunnel.

Cyclic fatigue, bending resistance, and surface roughness of ProTaper Gold and EdgeEvolve files in canals with single- and double-curvature

Wafaa A. Khalil,Zuhair S. Natto 대한치과보존학회 2019 Restorative Dentistry & Endodontics Vol.44 No.2

Objectives: The purpose of this study was to evaluate the cyclic fatigue, bending resistance, and surface roughness of EdgeEvolve (EdgeEndo) and ProTaper Gold (Dentsply Tulsa Dental Specialties) nickel-titanium (NiTi) rotary files. Materials and Methods: The instruments (n = 15/each) were tested for cyclic fatigue in single- (60° curvature, 5-mm radius) and double-curved (coronal curvature 60°, 5-mm radius, and apical curvature of 30° and 2-mm radius) artificial canals. The number of cycles to fracture was calculated. The bending resistance of both files were tested using a universal testing machine where the files were bent until reach 45°. Scanning electron microscopy and x-ray energy-dispersive spectrometric analysis were used for imaging the fractured segments, while the atomic force microscope was used to quantify the surface roughness average (Ra). Results: EdgeEvolve files exhibited higher cyclic fatigue resistance than ProTaper Gold files in single- and double-curved canals (p < 0.05) and both files were more resistant to cyclic fatigue in single-curved canals than double-curved canals (p < 0.05). EdgeEvolve files exhibited significantly more flexibility than did ProTaper Gold files (p < 0.05). Both files had approximately similar Ni and Ti contents (p > 0.05). EdgeEvolve files showed significantly lower Ra values than ProTaper Gold files (p < 0.05). Conclusions: Within the limitation of this study, EdgeEvolve files exhibited significantly higher cyclic fatigue resistance than ProTaper Gold files in both single- and double-curved canals.

A Multi-Objective TRIBES/OC-SVM Approach for the Extraction of Areas of Interest from Satellite Images

( Wafaa Benhabib ),( Hadria Fizazi ) 한국정보처리학회 2017 Journal of information processing systems Vol.13 No.2

In this work, we are interested in the extraction of areas of interest from satellite images by introducing a MOTRIBES/ OC-SVM approach. The One-Class Support Vector Machine (OC-SVM) is based on the estimation of a support that includes training data. It identifies areas of interest without including other classes from the scene. We propose generating optimal training data using the Multi-Objective TRIBES (MO-TRIBES) to improve the performances of the OC-SVM. The MO-TRIBES is a parameter-free optimization technique that manages the search space in tribes composed of agents. It makes different behavioral and structural adaptations to minimize the false positive and false negative rates of the OC-SVM. We have applied our proposed approach for the extraction of earthquakes and urban areas. The experimental results and comparisons with different state-of-the-art classifiers confirm the efficiency and the robustness of the proposed approach.

A Multi-Objective TRIBES/OC-SVM Approach for the Extraction of Areas of Interest from Satellite Images

Benhabib, Wafaa,Fizazi, Hadria Korea Information Processing Society 2017 Journal of information processing systems Vol.13 No.2

In this work, we are interested in the extraction of areas of interest from satellite images by introducing a MO-TRIBES/OC-SVM approach. The One-Class Support Vector Machine (OC-SVM) is based on the estimation of a support that includes training data. It identifies areas of interest without including other classes from the scene. We propose generating optimal training data using the Multi-Objective TRIBES (MO-TRIBES) to improve the performances of the OC-SVM. The MO-TRIBES is a parameter-free optimization technique that manages the search space in tribes composed of agents. It makes different behavioral and structural adaptations to minimize the false positive and false negative rates of the OC-SVM. We have applied our proposed approach for the extraction of earthquakes and urban areas. The experimental results and comparisons with different state-of-the-art classifiers confirm the efficiency and the robustness of the proposed approach.

Non-Gaussian approach for equivalent static wind loads from wind tunnel measurements

Kassir, Wafaa,Soize, Christian,Heck, Jean-Vivien,De Oliveira, Fabrice Techno-Press 2017 Wind and Structures, An International Journal (WAS Vol.25 No.6

A novel probabilistic approach is presented for estimating the equivalent static wind loads that produce a static response of the structure, which is "equivalent" in a probabilistic sense, to the extreme dynamic responses due to the unsteady pressure random field induced by the wind. This approach has especially been developed for complex structures (such as stadium roofs) for which the unsteady pressure field is measured in a boundary layer wind tunnel with a turbulent incident flow. The proposed method deals with the non-Gaussian nature of the unsteady pressure random field and presents a model that yields a good representation of both the quasi-static part and the dynamical part of the structural responses. The proposed approach is experimentally validated with a relatively simple application and is then applied to a stadium roof structure for which experimental measurements of unsteady pressures have been performed in boundary layer wind tunnel.

Tone-Burst Auditory Brainstem Response and Cortical Potentials in Diagnosis of Syndromic Auditory Neuropathy Spectrum Disorder

Kaf Wafaa A.,Reiter Samantha,Brodeur Amanda,White-Minnis Letitia,Deal William 대한청각학회 2023 Journal of Audiology & Otology Vol.27 No.3

In this study, we report our findings of comprehensive evaluation in a man with syndromic craniofacial features, cognitive impairment, and hearing loss. The patient underwent psychological and genetic testing and screening for 133 genetic mutations associated with hearing loss, as well as extensive audiological evaluation to assess the auditory pathway between the middle ear and the auditory cortex. Psychological testing showed moderate cognitive impairment. Genetic testing did not reveal a genetic mutation for hearing loss. Audiological evaluation revealed mixed hearing loss and signs of auditory neuropathy spectrum disorder (ANSD) despite absence of otoacoustic emissions and an absent click-evoked auditory brainstem response (ABR) without recording of cochlear microphonics (CM). ANSD was characterized by abnormal speech discrimination, bilateral robust CM to 2,000 Hz tone-burst (TB) ABR, and abnormal left thalamocortical and cortical pathways diagnosed based on auditory middle latency and cortical N1-P2 responses. These behavioral and electrophysiological findings suggest post-synaptic ANSD at the brainstem level. An abnormal left thalamocortical auditory pathway may be attributable to the combined effect of lack of neural synchrony secondary to ANSD mainly on the left and/or brain injury. The findings in this study support the use of TB ABR and auditory cortical potentials in the ANSD test protocol and in patients with craniofacial anomalies.

No Association Between Insomnia Severity, and Discrepancy Between Desired Time in Bed and Desired Total Sleep Time Among Shift-Working Nursing Professionals

Bzeih Wafaa,Kim Sohyeong,Yi Kikyoung,Chung Seockhoon 대한수면학회 2023 sleep medicine research Vol.14 No.3

Background and Objective This study aimed to explore whether the discrepancy between a patient’s desired time in bed and desired total sleep time (DBST index) can be used as a tool to assess the insomnia severity of shift-working nursing professionals.Methods Two studies were conducted during two different times among two groups of shiftworking nursing professionals working in COVID-19 inpatient wards (study I), or nurses who witnessed patient death during the previous 2 years (study II), using a single voluntary survey. The survey was completed by a total of 366 participants: 226 in the first study, and 140 in the second. Participants’ age, sex, marital status, and past psychiatric history were collected. In addition to questions regarding the DBST index, the Glasgow Sleep Effort Scale (GSES), Dysfunctional Beliefs about Sleep-2 items (DBS-2), and the Insomnia Severity Index (ISI) were assessed.Results In both studies, the DBST index did not reflect insomnia severity, preoccupation with sleep, or dysfunctional beliefs about sleep in the linear regression analysis. In addition, ISI was expected by GSES (β = 0.67 in study I, β = 0.62 in study II, all p < 0.001) and DBS-2 (β = 0.16 in study II, p = 0.020), but not by the DBST index.Conclusions It was observed that the DBST index was not significantly associated with insomnia severity, preoccupation with sleep, or dysfunctional beliefs about sleep in two studies done among shift working-nursing professionals.

Cyclic fatigue, bending resistance, and surface roughness of ProTaper Gold and EdgeEvolve files in canals with single- and double-curvature

Khalil, Wafaa A.,Natto, Zuhair S. The Korean Academy of Conservative Dentistry 2019 Restorative Dentistry & Endodontics Vol.44 No.2

Objectives: The purpose of this study was to evaluate the cyclic fatigue, bending resistance, and surface roughness of EdgeEvolve (EdgeEndo) and ProTaper Gold (Dentsply Tulsa Dental Specialties) nickel-titanium (NiTi) rotary files. Materials and Methods: The instruments (n = 15/each) were tested for cyclic fatigue in single- ($60^{\circ}$ curvature, 5-mm radius) and double-curved (coronal curvature $60^{\circ}$, 5-mm radius, and apical curvature of $30^{\circ}$ and 2-mm radius) artificial canals. The number of cycles to fracture was calculated. The bending resistance of both files were tested using a universal testing machine where the files were bent until reach $45^{\circ}$. Scanning electron microscopy and x-ray energy-dispersive spectrometric analysis were used for imaging the fractured segments, while the atomic force microscope was used to quantify the surface roughness average (Ra). Results: EdgeEvolve files exhibited higher cyclic fatigue resistance than ProTaper Gold files in single- and double-curved canals (p < 0.05) and both files were more resistant to cyclic fatigue in single-curved canals than double-curved canals (p < 0.05). EdgeEvolve files exhibited significantly more flexibility than did ProTaper Gold files (p < 0.05). Both files had approximately similar Ni and Ti contents (p > 0.05). EdgeEvolve files showed significantly lower Ra values than ProTaper Gold files (p < 0.05). Conclusions: Within the limitation of this study, EdgeEvolve files exhibited significantly higher cyclic fatigue resistance than ProTaper Gold files in both single- and double-curved canals.

Medication-Related Osteonecrosis of the Jaw Associated with Palatal Bone and Soft Tissue Trauma: A Case Report

Harpreet Singh,Wafaa Saleh,Seunghee Cha,Joseph Katz,Axel Ruprecht 대한안면통증∙구강내과학회 2019 Journal of Oral Medicine and Pain Vol.44 No.1

The aim of this case report is to present a case of 68-year-old male with a history of multiple myeloma and the intravenous use of Zometa (zoledronic acid) who had developed medication-related osteonecrosis of the jaw (MRONJ) following a hot pizza burn to the palate. Clinical and radiographic findings revealed grade 1 MRONJ of the right side of the hard palate. Soft tissue trauma and delayed epithelialization may be associated with some cases of MRONJ. Patients on anti-resorptive medications or anti-angiogenic drugs should be informed of the risk of bone exposure and subsequent MRONJ secondary to physical/chemical insults to the bone and soft tissue in the oral cavity.