The Degree of Using Cloud Computing Applications in the E-learning Environment and its Obstacles for Secondary School Students in the Capital Amman Governorate from the Point View of their Teachers

The study aimed to reveal the degree of use of cloud computing applications in the e-learning environment and the obstacles facing secondary school students in the Capital Governorate of Amman from the point of view of their teachers. The study adopted the descriptive survey method, and to collect data, a questionnaire was developed in the form of a scale consisting of (30) items, consisting of two parts, the first to measure the degree of use of cloud computing applications in the e-learning environment for secondary school students in the Amman governorate, and the second to measure the obstacles of cloud computing applications In the e-learning environment, its validity and reliability were confirmed, It was applied to an available sample consisting of (294) male and female teachers who were chosen by the simple random method. The results of the study showed that the degree of using cloud computing applications in the e-learning environment for secondary school students in the capital Amman governorate from the point of view of their teachers was medium, and the results of the study indicated that the degree of obstacles facing secondary school students in the capital governorate came to a high degree from the point of view of their teachers. In addition to the absence of a statistically significant difference in the degree of using cloud computing applications in the e-learning environment for secondary school students in the capital, Amman, from the point of view of their teachers, due to the variables of specialization, years of service, and the interaction between them

A robust fault detection method of rolling bearings using modulation signal bispectrum analysis

Envelope analysis is a widely used method for bearing fault detection. To obtain high detection accuracy, it is critical to select an optimal narrowband for envelope demodulation. Fast Kurtogram is an effective method for optimal narrowband selection. However, fast Kurtogram is not sufficiently robust because it is very sensitive to random noise and large aperiodic impulses which normally exist in practical application. To achieve the purpose of denoising and frequency band optimization, this paper proposes a new fault detector based on modulation signal bispectrum analysis (MSB) for bearing fault detection. As MSB results highlight the modulation effects by suppressing stationary random noise and discrete aperiodic impulses, the detector developed using high magnitudes of MSB can provide optimal frequency bands for fault detection straightforward. Performance evaluation results using both simulated data and experimental data show that the proposed method produces more effective and robust detection results for different types of bearing faults, compared with optimal envelope analysis using fast Kurtogram

Diagnosis of Combination Faults in a Planetary Gearbox using a Modulation Signal Bispectrum based Sideband Estimator

This paper presents a novel method for diagnosing combination faults in planetary gearboxes. Vibration signals measured on the gearbox housing exhibit complicated characteristics because of multiple modulations of concurrent excitation sources, signal paths and noise. To separate these modulations accurately, a modulation signal bispectrum based sideband estimator (MSB-SE) developed recently is used to achieve a sparse representation for the complicated signal contents, which allows effective enhancement of various sidebands for accurate diagnostic information. Applying the proposed method to diagnose an industrial planetary gearbox which coexists both bearing faults and gear faults shows that the different severities of the faults can be separated reliably under different load conditions, confirming the superior performance of this MSB-SE based diagnosis scheme

Percutaneous embolization of contained iatrogenic vesicourethral fistula using Amplatzer vascular plug and N-butyl-2-cyanoacrylate : a case report

Purpose: Reports on percutaneous embolization of vesicourethral anastomotic fistula are limited. Case presentation: A 59-year-old male presented with persistent contained vesicourethral fistula following low anterior resection and radical retropubic prostectomy for rectal cancer. A contained fistula with urinary leakage of 350 ml/day through a Jackson-Pratt (JP) tube was found at the posterior aspect of the vesicourethral anastomotic site on cystography. After 1 month of failed conventional urinary drainage manoeuvre, percutaneous embolization of the contained fistula was successfully performed through the JP tube. An Amplatzer vascular plug (AVP) was used to block the fistula and N-butyl-2-cyanoacrylate (NBCA) was used to obliterate the urinoma cavity. Computed tomography scans at 1-month and 1-year follow-ups showed stable AVP position and complete obliteration of the cavity by NBCA. Conclusions: The contained vesicourethral anastomotic fistula was successfully managed with AVP and NBCA via a JP drainage tube. It is expected that AVP will block the fistula and NBCA will obliterate the urinoma cavity effectively

Anti-ficolin-2 Antibody: Could it be a Predictor of Proliferative Lupus Nephritis in Lupus Patients?

Background: Nephritis is a challenging domain of systemic lupus erythematosus (SLE). There is a growing need for identification of a non-invasive marker for diagnosing and monitoring nephritis.Objective: To explore the relevance of using anti-ficolin-2 antibody (Anti-FCN2) as a biomarker for detecting lupus nephritis (LN), and its relation to renal biopsy histopathology and disease activity.Patients and Methods: Sixty SLE patients were compared to 30 apparently healthy individuals. Thirty of the patients were LN patients (documented by a recent renal biopsy). Full history, examination and laboratory investigations were done. Activity was assessed by SLE disease activity index (SLEDAI) score, and Anti-FCN2 titer was measured by enzyme-linked immunosorbent assay technique (ELISA).Results: Forty-four of our SLE patients were in disease activity by SLEDAI score. Anti-FCN2 titer was significantly higher among SLE patients compared to control group (p value <0.001). It was also higher among patients with high disease activity compared to those with low disease activity and cutoff value was at 37 ng/ml (p value is <0.001). AntiFCN2 titer was significantly higher among patients with LN compared to those without LN (p value is <0.001) with best cutoff value at 72.50 ng/ml. Regarding LN patients, it was significantly higher among patients with proliferative changes than LN patients with non-proliferative changes (p value is 0.05) with best cutoff value at 155 ng/ml.Conclusion: Anti-FCN2 shows promising results as a biomarker for lupus disease activity, especially regarding LN and proliferative changes. Further longitudinal studies on larger samples are needed to confirm

Multi-component reactions of cyclohexan-1,3-dione to synthesize heterocyclic derivatives with c-Met enzymatic activity, anti-prostate, anti-proliferative and tyrosine kinase activities

ABSTRACT. We are aiming in this work to synthesize target molecules not only possess anti-tumor activities but also kinase inhibitors. The target molecules were obtained starting from aryl hydrazones of cyclohexan-1,3-dione  followed by its heterocyclization reactions to produce anticancer molecules. The multi-component reactions of the arylhydrazocyclohexan-1,3-dione derivatives 3a-c produced the 1,4,5,6,7,8-hexahydroquinoline derivatives 6a-r and the 4,5,6,8-tetrahydrochromeno[2,3-c]pyrazole derivatives 10a-c. Other multi-component reactions were demonstrated. The anti-proliferative activity of the synthesized compounds toward the six cancer cell lines namely A549, H460, HT-29, MKN-45, U87MG, and SMMC-7721 was studied. In addition the c-Met enzymatic activities and inhibition toward the prostate cancer cell PC-3 were measured. The results obtained in most cases, indicated that the presence of electronegative Cl group through the molecule favour the inhibitions.                 KEY WORDS: Multi-component reactions, Cyclohexan-1,3-dione, Chromene, Chromeno[2,3-c]pyrazole, Cytotoxicity   Bull. Chem. Soc. Ethiop. 2022, 36(1), 119-136.                                                             DOI: https://dx.doi.org/10.4314/bcse.v36i1.11                                                      &nbsp

Uses of chalcone acetophenone to synthesis heterocyclic compounds with cytotoxic and c-Met kinase activities

ABSTRACT. The aim of present study was the uses of a series of α,β-unsaturated carbonyl compounds (chalcones), in the synthesis of pyridine, pyran, thiophene, thiazole, together with their uses in heterocyclic synthesis. The work has resulted in the synthesis of a variety of 2,5-dihydropyridine, hydrazide-hydrazone, thiophene derivatives, coumarin, pyran and thiazolo[4,5-d]thiazole derivatives. The antitumor activities of the newly synthesized products were carried out against three cancer cell lines namely MCF-7, NCI-H460 and SF-268 and normal human cell line WI38.  In addition, the inhibitions of most of the synthesized compounds against             c-Met kinase were studied and results showed that many compounds were of high inhibitions, and these are considered as promising anticancer agents. The results obtained encouraged further work in the future.    KEY WORDS: Chalcones, Heterocyclic, Pyridine, Pyran, Thiophene, Thiazole, Antitumor Bull. Chem. Soc. Ethiop. 2022, 36(1), 149-172.                                                             DOI: https://dx.doi.org/10.4314/bcse.v36i1.13                                                      &nbsp

The Optimization of Vibration Data Analysis for the Detection and Diagnosis of Incipient Faults in Roller Bearings

The rolling element bearing is a key component of many machines. Accurate and timely diagnosis of its faults is critical for proactive predictive maintenance. The research described in this thesis focuses on the development of techniques for detecting and diagnosing incipient bearing faults. These techniques are based on improved dynamic models and enhanced signal processing algorithms. Various common fault detection techniques for rolling element bearings are reviewed in this work and a detailed experimental investigation is described for several selected methods. Envelope analysis is widely used to obtain the bearing defect harmonics from the spectrum of the envelope of a vibration signal. This enables the detection and diagnosis of faults, and has shown good results in identifying incipient faults occurring on the different parts of a bearing. However, a critical step in implementing envelope analysis is to determine the frequency band that contains the signal component corresponding to the bearing fault (the one with highest signal to noise ratio). The choice of filter band is conventionally made via manual inspection of the spectrum to identify the resonant frequency where the largest change has occurred. In this work, a spectral kurtosis (SK) method is enhanced to enable determination of the optimum envelope analysis parameters, including the filter band and centre frequency, through a short time Fourier transform (STFT). The results show that the maximum amplitude of the kurtogram indicates the optimal parameters of band pass filter that allows both outer race and inner race faults to be determined from the optimised envelope spectrum. A performance evaluation is carried out on the kurtogram and the fast kurtogram, based on a simulated impact signal masked by different noise levels. This shows that as the signal to noise ratio (SNR) reaches as low as -5dB the STFT-based kurtogram is more effective at identifying periodic components due to bearing faults, and is less influenced by irregular noise pulses than the wavelet based fast kurtogram. A study of the accuracy of rolling-bearing diagnostic features in detecting bearing wear processes and monitoring fault sizes is presented for a range of radial clearances. Subsequently, a nonlinear dynamic model of a deep groove ball bearing with five degrees of freedom is developed. The model incorporates local defects and clearance increments in order to gain the insight into the bearing dynamics. Simulation results indicate that the vibrations at fault characteristic frequencies exhibit significant variability for increasing clearances. An increased vibration level is detected at the bearing characteristic frequency for an outer race fault, whereas a decreased vibration level is found for an inner race fault. Outcomes of laboratory experiments on several bearing clearance grades, with different local defects, are used herein for model validation purposes. The experimental validation indicates that the envelope spectrum is not accurate enough to quantify the rolling element bearing fault severity adequately. To improve the results, a new method has been developed by combining a conventional bispectrum (CB) and modulation signal bispectrum (MSB) with envelope analysis. This suppresses the inevitable noise in the envelope signal, and hence provides more accurate diagnostic features. Both the simulation and the experimental results show that MSB extracts small changes from a faulty bearing more reliably, enabling more accurate and reliable fault severity diagnosis. Moreover, the vibration amplitudes at the fault characteristic frequencies exhibit significant changes with increasing clearance. However, the vibration amplitude tends to increase with the severity of an outer race fault and decrease with the severity of an inner race fault. It is therefore necessary to take these effects into account when diagnosing the size of a defect

EFFECT OF ADDITION OF NANO SILICON DIOXIDE TO CEMENT BRICKS: PREPARATION AND CHARACTERICTICS

The aim of the research is to design and produce a durable, and high load, bearing build constructing bricks based on cement, sand, and aggregates with the addition of Nano silica, studying the effect of the added materials to get a background about the impact of the Nano silica on the ability of using such a product. The cement used is 52.5 grade which represent the strength of the cement, sand with particle size 300-600 micrometer, aggregates with diameter lays between 0.5-1 cm better to use smaller size, water, and finally Nano-silica with particle size 17 nm with purity higher than 99.9%. the final size of the produced brick is a cubic shape with 4*4*4 cm in dimension. The research results have been achieved and stated that as the percentage of the Nano silica increase the strength increase and the bricks withstood for more loads and nominated the 10% Nano-silica of the total weight or of the cement weight as the best percentage among the prepared samples percentages and gives a strength of 6.4 MPa

A Study Of The Diagnostic Amplitude Of Rolling Bearing Under Increasing Radial Clearance Using Modulation Signal Bispectrum

The rolling element bearing is a key part of machines. The accurate and timely diagnosis of its faults is critical for predictive maintenance. Most re-searches have focused on the fault location identification. To estimate the fault severity accurately, this paper focuses on the study of roller bearing vibration amplitude under increasing radial clearances due to inevitable wear using the modulation signal bispectrum (MSB). The experiment is carried out for bearings with two different clearances for the inner race fault and the outer race fault cases. The results show that the vibration amplitudes at fault characteristic frequencies exhibit significant changes with increasing clearances. However, the amplitudes of vibrations tend to increase with the severity of the outer race fault and decrease with the severity of the inner race fault. Therefore, it is necessary to take into account these effects in diagnosing the size of defect