Exceptional Points of Degeneracy Induced by Linear Time-Periodic Variation

We present a general theory of exceptional points of degeneracy (EPD) in periodically time-variant systems. We show that even a single resonator with a time-periodic component is able to develop EPDs, contrary to parity-time- (PT) symmetric systems that require two coupled resonators. An EPD is a special point in a system parameter space at which two or more eigenmodes coalesce in both their eigenvalues and eigenvectors into a single degenerate eigenmode. We demonstrate the conditions for EPDs to exist when they are directly induced by time-periodic variation of a system without loss and gain elements. We also show that a single resonator system with zero time-average loss-gain exhibits EPDs with purely real resonance frequencies, yet the resonator energy grows algebraically in time since energy is injected into the system from the time-variation mechanism. Although the introduced concept and formalism are general for any time-periodic system, here, we focus on the occurrence of EPDs in a single LC resonator with time-periodic modulation. These findings have significant importance in various electromagnetic and photonic systems and pave the way for many applications, such as sensors, amplifiers, and modulators. We show a potential application of this time-varying EPD as a highly sensitive sensor

Saudi EFL Learners’ Perceptions of the Benefits of ICT Integration into English Learning

This study focuses on exploring the benefits perceived by Saudi English as a Foreign Language (EFL) students of integrating Information and Communication Technology (ICT) into English learning and teaching. It also aims to determine their use of ICT and their attitudes to its use in learning and teaching. Data were collected through a questionnaire survey from 120 female preparatory year students studying at an English Language Institute (ELI) at a University in Saudi Arabia. The quantitative data obtained were analysed through statistical descriptive analysis. The findings of the study reveal positive attitudes among students on the use of ICT in English learning and teaching. The majority of the students used ICT to access English learning resources to learn English. Students also perceived ICT as a useful tool that could be used to access authentic materials. In addition, students strongly agreed that ICT can improve their English learning and helps increase learning autonomy. The findings of the study were discussed and compared with the findings of related literature. This study provides valuable insights on how students perceive ICT as a tool of learning and teaching that can help provide a better English learning experience. Moreover, this study contributes to the research area of ICT use in EFL learning in the Arab higher education context

Značajke legura SnBi5Pbx dobivenih prskanjem

Sn-5wt.%Bi binary master alloy was prepared by melt spinning. Ternary alloys with different Pb contents of 0.5 to 2.5 wt.% were prepared by the same technique. All alloys were irradiated with 1.2 MGy g-radiation at room temperature. The internal friction, thermal diffusivity and Young`s modulus were measured at room temperature, before and after irradiation by applying the resonance technique. DTA thermograms and X-rays diffraction patterns were obtained for the tested alloys. The results show a remarkable dependence of the measured properties on both the Pb content and irradiation doze. The observed changes are attributed to the defects induced by irradiation and to the uncontrolled dispersion of Pb content in the matrix which leads to the composition inhomogeneity and density fluctuations.Pripremali smo osnovnu dvokomponentnu leguru Sn-5wt.%Bi kao i trokomponentne legure s dodacima Pb od 0.5 do 2.5 tež.% metodom prskanja na aluminijski valjak. Sve smo uzorke također ozračili na sobnoj temperaturi γ-zračenjem do doze 1.2 MGy. Mjerili smo unutarnje trenje, toplinsku difuznost i Youngov modul na sobnoj temperaturi, prije i nakon ozračivanja, rezonantnom metodom. Za ispitane uzorke dobili smo DTA termograme i rentgenske difrakcijske snimke. Ishodi mjerenja pokazuju jaku ovisnost mjerenih svojstava o sadržaju Pb i dozi ozračivanja. Opažene se promjene tumače defektima izazvanim zračenjem odnosno neupravljanom disperzijom Pb u matrici legure koji dovode do nejednolikosti sastava i promjenljivosti gustoće

Značajke legura SnBi5Pbx dobivenih prskanjem

Sn-5wt.%Bi binary master alloy was prepared by melt spinning. Ternary alloys with different Pb contents of 0.5 to 2.5 wt.% were prepared by the same technique. All alloys were irradiated with 1.2 MGy g-radiation at room temperature. The internal friction, thermal diffusivity and Young`s modulus were measured at room temperature, before and after irradiation by applying the resonance technique. DTA thermograms and X-rays diffraction patterns were obtained for the tested alloys. The results show a remarkable dependence of the measured properties on both the Pb content and irradiation doze. The observed changes are attributed to the defects induced by irradiation and to the uncontrolled dispersion of Pb content in the matrix which leads to the composition inhomogeneity and density fluctuations.Pripremali smo osnovnu dvokomponentnu leguru Sn-5wt.%Bi kao i trokomponentne legure s dodacima Pb od 0.5 do 2.5 tež.% metodom prskanja na aluminijski valjak. Sve smo uzorke također ozračili na sobnoj temperaturi γ-zračenjem do doze 1.2 MGy. Mjerili smo unutarnje trenje, toplinsku difuznost i Youngov modul na sobnoj temperaturi, prije i nakon ozračivanja, rezonantnom metodom. Za ispitane uzorke dobili smo DTA termograme i rentgenske difrakcijske snimke. Ishodi mjerenja pokazuju jaku ovisnost mjerenih svojstava o sadržaju Pb i dozi ozračivanja. Opažene se promjene tumače defektima izazvanim zračenjem odnosno neupravljanom disperzijom Pb u matrici legure koji dovode do nejednolikosti sastava i promjenljivosti gustoće

Application of Advanced MRI to Fetal Medicine and Surgery

Robust imaging is essential for comprehensive preoperative evaluation, prognostication, and surgical planning in the field of fetal medicine and surgery. This is a challenging task given the small fetal size and increased fetal and maternal motion which affect MRI spatial resolution. This thesis explores the clinical applicability of post-acquisition processing using MRI advances such as super-resolution reconstruction (SRR) to generate optimal 3D isotropic volumes of anatomical structures by mitigating unpredictable fetal and maternal motion artefact. It paves the way for automated robust and accurate rapid segmentation of the fetal brain. This enables a hierarchical analysis of volume, followed by a local surface-based shape analysis (joint spectral matching) using mathematical markers (curvedness, shape index) that infer gyrification. This allows for more precise, quantitative measurements, and calculation of longitudinal correspondences of cortical brain development. I explore the potential of these MRI advances in three clinical settings: fetal brain development in the context of fetal surgery for spina bifida, airway assessment in fetal tracheolaryngeal obstruction, and the placental-myometrial-bladder interface in placenta accreta spectrum (PAS). For the fetal brain, MRI advances demonstrated an understanding of the impact of intervention on cortical development which may improve fetal candidate selection, neurocognitive prognostication, and parental counselling. This is of critical importance given that spina bifida fetal surgery is now a clinical reality and is routinely being performed globally. For the fetal trachea, SRR can provide improved anatomical information to better select those pregnancies where an EXIT procedure is required to enable the fetal airway to be secured in a timely manner. This would improve maternal and fetal morbidity outcomes associated with haemorrhage and hypoxic brain injury. Similarly, in PAS, SRR may assist surgical planning by providing enhanced anatomical assessment and prediction for adverse peri-operative maternal outcome such as bladder injury, catastrophic obstetric haemorrhage and maternal death

Optimization of EDM Process Factors for Machining Al-Si Alloy Using Response Surface Methodology

        يقدم هذا البحث نهجا متكاملا لنمذجة العملية والأمثلية متعددة الاهداف لمتغيرات التشغيل بالشرارة الكهربائية لسبيكة الالمنيوم سيليكون (Al-Si) اعتمادا على نمط استجابة السطح (RSM) إلى جانب تكنيك دالة الرغبة (DF). أختيرت ثلاث متغيرات منفصلة كمدخلات وهي تيار النبضة (Ip)، فترة إفراغ النبضة (Ton) وفترة توقف النبضة (Toff) للتأكد من تأثير المتغيرات الثلاث سابقة الذكر على المخرجات المتمثلة بمعدل إزالة المادة (MRR)، معدل بلى القطب (EWR) وخشونة السطح (Ra). تحليل عام للتفاوت (ANOVA) عند درجة من الأهمية مقدارها 5% لتعيين المعاملات الأكثر تأثيرا، وأنجز اختبار مدى كفاءة كافة النماذج. ولفهم السلوك الشامل لقابلية تشغيل لسبيكة الالمنيوم سيليكون (Al-Si) تحت أوضاع التشغيل المتفاوتة، تم إجراء تحليل التأثير الأساسي. بينت النتائج ان معدل الازالة المعدنية يزداد مع رفع تيار النبضة وفترة إفراغ النبضة. يمكن الاستحصال ايضا على نقصان في كل من معدل بلى القطب وخشونة السطح عن طريق خفض تيار النبضة ووقت إفراغ النبضة. ومع ذلك، فإن تيار النبضة هو العامل المتحكم (الاكثر تأثيرا) على معدل الازالة المعدنية وخشونة السطح متبوعا زمن تفريغ النبضة وزمن توقف النبضة، في حين أن في معدل بلى القطب فان تيار النبضة هو العامل الاكثر تأثيرا يليه زمن توقف النبضة وزمن إفراغ النبضة. أخيرا استعملت أسلوب الامثلية متعددة الاهداف بالاعتماد على نظرية دالة الرغبة للاستحصال على المقدار الامثل لمتغيرات التشغيل بحيث يمكن الاستحصال من خلالها على اعلى مقدار لمعدل الازالة المعدنية وأدنى مقدار لكل من متوسط بلى القطب وخشونة السطح مع المتغيرات المؤثرة.This work exhibits an incorporated way to deal with the procedure demonstrating and multi-target improvement of EDM parameters of Al-Si based on response surface methodology (RSM) combined with desirability function (DF) method. The’ effect’ of’ process’ parameters   for’ example, pulse current (Ip), pulse’ on’ time’ (Ton) as well as pulse’ off’ time’ (Toff) on’ metal removal’ rate’ (MRR), electrode’ wear’ rate’ (EWR) and’ surface’ roughness’ (Ra), were analyzed. An extensive investigation of difference (ANOVA) at fixed indicative level of 5%, was done to completely distinguish the most persuasive parameters, and the sufficiency of all fitted relapse models were checked. To completely comprehend the trademark machinability conduct under various EDM conditions, fundamental effect investigation. The results indicate that MRR increases with the rising Ip and Ton. Low EWR and Ra can be acquired by diminishing Ip and Ton. Be that as it may, the Ip is the most commanding parameter pursued by Ton and Toff for MRR and Ra whereas in the EWR, the Ip is the foremost factor, followed by the Toff and Ton. Lastly, a multi-optimization way dependent upon the desirability function (DF) idea was used to discover ideal blends of machining parameters so that it was capable to produce the the most extreme estimation of MRR and least estimations of EWR and Ra, inside the noteworthy information parameters

Tinjauan Yuridis Terhadap Penyertaan Dalam Tindak Pidana Pemerkosaan Anak

Pada hakikatnya Negara Indonesia yang disebut dengan negara hukum memiliki berbagai aturan yang harus ditaati tanpa terkecuali. Salah satu masalah di Indonesia maraknya kasus perkosaan yang terdengar ditengah-tengah masyarakat. Apalagi korban perkosaan adalah anak dibawah umur dan pelakunya lebih dari seorang atau disebut penyertaan yang artinya meliputi semua bentuk turut serta atau terlibatnya seorang atau beberapa orang, baik secara psikis maupun secara fisik dengan melakukan masing-masing perbuatan sehingga melahirkan suatu tindak pidana. Penyertaan tindak pidana termuat dalam Pasal 55 KUHP, para pembuat (mededader), yang melakukan (pleger), yang menyuruh lakukan (doenpleger), yang turut serta melakukan (medepleger), dan yang sengaja menganjurkan (uitlokken). Tujuan penelitian ini untuk mengetahui bentuk penyertaan dalam tindak pidana perkosaan yang memenuhi unsur Pasal 55 KUHP. Penelitian ini juga dilakukan untuk mengetahui pertimbangan hakim dalam menjatuhkan putusan terhadap penyertaan dalam tindak pidana perkosaan anak dipidana atau dibebaskan. Penelitian ini menggunakan jenis penelitian normatif, yang berkaitan dengan asas-asas hukum kaidah-kaidah hukum termasuk kategori penelitian normatif, dan berada dalam tataran filsafat hukum. Penelitian ini hanya menggunakan pengumpulan data sekunder, pengumpulan data sekunder dilakukan melalui studi dokumentasi atau studi kepustakaan (library research). Berdasarkan hasil penelitian diketahui bahwa bentuk penyertaan dalam Putusan No.24/Pid.Sus/A/2012/PN.Pso dan No.280/Pid.Sus/2016/PN.Gns adanya yang melakukan dan yang turut serta melakukan sehingga unsur Pasal 55 KUHP terpenuhi pada kedua putusan tersebut. Putusan No.24/Pid.Sus/A/2012/PN.Pso Majelis Hakim menjatuhkan putusan bebas kepada para terdakwa tanpa mempertimbangkan alat bukti serta membebaskan para terdakwa dari dakwaan penuntut umum, hakim membebaskan mereka dan dinyatakan tidak bersalah. Pada Putusan Nomor 280/Pid.Sus/2016/PN.Gns dengan menggunakan alat bukti dan barang bukti untuk memenuhi dakwaan penuntut umum, para terdakwa dinyatakan bersalah dan hakim menjatuhkan hukuman pidana penjara masing-masing 10 tahun serta membayar denda Rp.100.000.000. Sebaiknya dalam dalam pertimbangan hukum hakim dalam menjatuhkan putusan dalam perkara ini, masih perlu lebih diperketat dengan tetap mengedepankan rasa keadilan, sehingga mampu memuaskan semua pihak dan sekaligus dapat memberikan efek jera bagi pelaku atau terdakwa. Bahkan bisa menjadi pelajaran bagi masyarakat untuk tidak melakukan tindak pidana karena setiap perbuatan yang melawan hukum harus dipertanggungjawabkan

Stigmatisation of Obesity and its Relation to the Perception of Controllability in Riyadh, Saudi Arabia: A cross-sectional study

Objectives: This study assessed the stigmatisation of obesity among a sample of the general population in Riyadh and its association with the perception of controllability. Methods: A cross-sectional analytical study was carried out in Riyadh, Saudi Arabia, during January–February 2021 and included 384 participants who were recruited through a convenience sampling method. The data were collected using a self-administrated online questionnaire. Statistical analysis was performed using John’s Macintosh Project Version 16.0.0. Results: Most of the participants had a low level of stigma towards obesity (72.8%), and gender and BMI were significantly associated with the level of stigma at (p = .0023) and (p = .0360) respectively. The association between the perception of controllable factors and the level of stigma was also significant (p = 0.0001). Conclusions: The data supported the hypothesis that there would be a significant association between stigmatisation on obesity and perception of controllability among the general population in Riyadh City. Regarding recommendations, the authors suggest that they should be based on joint international consensus statements for ending the stigma of obesity in different settings and categories, and should include the education of healthcare service providers and obese patients on the relationships shown in the findings. Keywords: Obesity, stigmatisation, perceptio

FLOATING RANITIDINE MICROPARTICULATES: DEVELOPMENT AND IN VITRO EVALUATION

Objective: Rapid and inconsistent gastrointestinal tract (GIT) transit could result in reduced drug efficiency and the need for frequent dose administration, which usually result in patients' incompliance. Ranitidine hydrochloride (RH), as a model drug is freely soluble, moisture sensitive drug with a short biological half-life (~2.5-3 h) and narrow absorption window in the initial part of the small intestine. The present study aimed to develop ranitidine floating multi-particulates (RFM) using melt granulation technique and investigation of the effect of lipids and additives on the physicochemical properties. Methods: RFM were prepared using Compritol® 888 ATO, glyceryl behenate, Cutina® HR, Cutina® GMS, hydrogenated castor oil, glyceryl monostearate, and beeswax as lipids and ethyl cellulose, Povidone® K 90 and Aerosil® 200 as release modifiers. The effect of the preparation method and additives, as well as storage for 6 mo at 40 °C, on floating and release characteristics were evaluated. Results: Size distribution indicated that the prepared formulations exhibited reasonably small floating micro particulates; more than 90% of the prepared microparticles were less than 710 µm. Hausner ratios and Carr's compressibility indices ranged from 1.17 to 1.29% and 14.54 to 22.4 %, respectively, and the angle of repose values was ≤40 °, indicating good flow properties. RFM containing Compritol® showed a relatively higher release properties compared to hydrogenated castor oil. Increasing the proportion of the fatty component was accompanied by retardation in RH release. The tested additives (PVP, ethyl cellulose, Aerosil®) resulted in different degrees of retardation of drug release. The percent-floating of RFM was almost 100% in all formulations with the exception of formulations prepared using glyceryl monostearate. FT-IR and DSC studies indicated the compatibility of the excipients with RH. Stability results revealed an insignificant change in RFM properties over 6 mo. Conclusion: The prepared microparticles exhibited optimum particle size, good compressibility, and flow properties. RFM containing Compritol® showed a relatively higher release properties compared to hydrogenated castor oil. Increasing the proportion of the fatty component was accompanied by retardation in RH release. The percent-floating of RFM was almost 100% in most formulations. FT-IR and DSC indicated good compatibility of the excipients with RH and insignificant change in RFM properties over 6 mo's storage

Graphene — A Platform for Sensor and Biosensor Applications

Graphene, mother of all carbon materials, has opened up new era of exploration due to its unique properties. Graphene, one-atom thick, exhibits a unique chemical structure and outstanding electronic, optical, thermal, and mechanical properties that made it compelling for various engineering applications. Graphene and graphene-based materials are promising candidates for fabricating state-of-the-art nano-scale sensors and biosensors. They featured with good conductivity and large specific surface area thereby; graphene-based sensors/biosensors performed well with good accuracy, rapidness, high sensitivity and selectivity, low detection limits, and long-term stability. They are ideally used as gas sensors, electrochemical sensors for heavy metal ions, immunosensors and dihydronicotinamide dinucleotide NADH, DNA, catecholamine neurotransmitters, paracetamol, glucose, H2O2, hemoglobin, and myoglobin biosensors. This chapter reviews the applications of graphene in nanotechnology since it came to the field particularly in sensing and biosensing applications. It updates the reader with the scientific progress of the current use of graphene as sensors and biosensors. There is still much room for the scientific research and application development of graphene-based theory, materials, and devices. Despite the vast amount of research already conducted on graphene for various applications, the field is still growing and many questions remain to be answered