Laboratory surface and solid state astrochemistry of biomolecular precursors on grain mimics

The existence of water (H2O) and acetonitrile (CH3CN) in various extraterrestrial environments attracts considerable attention as both molecules are crucial to understanding the genesis of life. This thesis involves investigations of the physical and chemical interactions of CH3CN and H2O ices condensed on an amorphous silica surface using ultrahigh vacuum-based surface science methods (reflection-absorption infrared spectroscopy, temperature programmed desorption, proton- and electron-irradiation experiments) in an effort to understand how such molecules will behave when they are processed by radiation and heat in space environments. The thermal behaviour of CH3CN on H2O and on the silica surface is governed by a balance of intermolecular forces and shows evidence for wetting of the silica surface (formation of a distinct first adsorption layer before multilayer growth) and of dewetting or island formation on the H2O surface (multilayer growth for all CH3CN exposures). This illustrates the importance of the substrate in determining the solid state growth morphology. Physical and chemical processes induced by 250 to 500 eV electrons have been investigated in the CH3CN and H2O systems. Such interactions promote only desorption from both CH3CN and H2O ice surfaces. 200 keV protons irradiation experiments of CH3CN ices, conducted by collaborators in Italy, in contrast showed evidence for chemical reactions in the solid CH3CN. Quantitative measurements of desorption and reaction cross-sections are used to reconcile this stark contrast. The impact of such processes in relation to H2O on astrophysics is investigated through simple numerical simulations using results derived from this work

Students Attitude Towards the Use of Social Media for Learning Purposes (Case Study: Al-Baha University, College of Sciences & Arts- Biljurashi)

The paper aimed at recognizing the attitudes of  using the  social networking sites among learners of English as a foreign language (EFL) in Saudi context. To the continued growth of the cyberspace era has brought with it a permanent change in the way that students interact and socialize. Based on analytical, descriptive method.  The study has reached to findings of it the bulk of the respondents report a positive attitude towards  social networking on their English language learning.And of the study recommendations more research studies in this area should be carried out,  for  order to develop best practices for its implementation in teaching and learning in EFL in the Saudi contexts. Keywords: Social network, Saudi Arabia academic purpose, students attitude

A Multi-Tier Distributed fog-based Architecture for Early Prediction of Epileptic Seizures

Epilepsy is the fourth most common neurological problem. With 50 million people living with epilepsy worldwide, about one in 26 people will continue experiencing recurring seizures during their lifetime. Epileptic seizures are characterized by uncontrollable movements and can cause loss of awareness. Despite the optimal use of antiepileptic medications, seizures are still difficult to control due to their sudden and unpredictable nature. Such seizures can put the lives of patients and others at risk. For example, seizure attacks while patients are driving could affect their ability to control a vehicle and could result in injuries to the patients as well as others. Notifying patients before the onset of seizures can enable them to avoid risks and minimize accidents, thus, save their lives. Early and accurate prediction of seizures can play a significant role in improving patients’ quality of life and helping doctors to administer medications through providing a historical overview of patient's condition over time. The individual variability and the dynamic disparity in differentiating between the pre-ictal phase (a period before the onset of the seizure) and other seizures phases make the early prediction of seizures a challenging task. Although several research projects have focused on developing a reliable seizure prediction model, numerous challenges still exist and need to be addressed. Most of the existing approaches are not suitable for real-time settings, which requires bio-signals collection and analysis in real-time. Various methods were developed based on the analysis of EEG signals without considering the notification latency and computational cost to support monitoring of multiple patients. Limited approaches were designed based on the analysis of ECG signals. ECG signals can be collected using consumer wearable devices and are suitable for light-weight real-time analysis. Moreover, existing prediction methods were developed based on the analysis of seizure state and ignored the investigation of pre-ictal state. The analysis of the pre-ictal state is essential in the prediction of seizures at an early stage. Therefore, there is a crucial need to design a novel computing model for early prediction of epileptic seizures. This model would greatly assist in improving the patients' quality of lives. This work proposes a multi-tier architecture for early prediction of seizures based on the analysis of two vital signs, namely, Electrocardiography (ECG) and Electroencephalogram (EEG) signals. The proposed architecture comprises of three tiers: (1) sensing at the first tier, (2) lightweight analysis based on ECG signals at the second tier, and (3) deep analysis based on EEG signals at the third tier. The proposed architecture is developed to leverage the potential of fog computing technology at the second tier for a real-time signal analytics and ubiquitous response. The proposed architecture can enable the early prediction of epileptic seizures, reduce the notification latency, and minimize the energy consumption on real-time data transmissions. Moreover, the proposed architecture is designed to allow for both lightweight and extensive analytics, thus make accurate and reliable decisions. The proposed lightweight model is formulated using the analysis of ECG signals to detect the pre-ictal state. The lightweight model utilizes the Least Squares Support Vector Machines (LS-SVM) classifier, while the proposed extensive analytics model analyzes EEG signals and utilizes Deep Belief Network (DBN) to provide an accurate classification of the patient’s state. The performance of the proposed architecture is evaluated in terms of latency minimization and energy consumption in comparison with the cloud. Moreover, the performance of the proposed prediction models is evaluated using three datasets. Various performance metrics were used to investigate the prediction model performance, including: accuracy, sensitivity, specificity, and F1-Measure. The results illustrate the merits of the proposed architecture and show significant improvement in the early prediction of seizures in terms of accuracy, sensitivity, and specificity

FLIPPED LEARNING IN ELT: EXPERIENCES FROM OMAN

Background and Purpose: Recently, flipped learning has become prevalent as a teaching and learning approach in international educational settings. A commonly cited advantage is to do self-study at home and to spend valuable classroom time on meaningful interactive learning activities. After the start of Covid-19 pandemic, the sudden transition to online teaching required many institutions to adopt a flipped learning approach. The current study was conducted at one of such institutions, namely Dhofar University in Oman. The aim of this paper is to identify the challenges met by both teachers and students using flipped learning during this transition as well as the solutions they developed to cope with them.   Methodology: This study implemented a mixed methods design for which the data were collected from two questionnaires and semi-structured interviews. One questionnaire was for teachers with 14 responses while the other was for students and could obtain responses from 68 students from the target population. From the list of teacher respondents, 10 were interviewed for deeper discussion of flipped learning context. The Questionnaires results were statistically calculated and descriptively analysed, whereas the interviews were thematically scrutinized.   Findings: The researchers found several major challenges including increased workload, lack of training, resistance to change, lacking IT skills, technical issues, non-completion of homework tasks and non-participation in live sessions. Teachers' resilience in the face of these challenges was noteworthy; especially in the form of peer support groups. The suggestions made by the teaching faculty for solutions are reported and discussed in the relevant sections of the article with reference to various research studies from different contexts.   Contributions: Despite the small scale and the specific context of the study, the results and discussion provide useful food for thought to educational practitioners and decision makers in wider international contexts when it comes to flipped learning challenges and coping mechanisms.    Keywords: Flipped learning, ELT, challenges, solutions, higher education.   Cite as: Eissa, A., Yapar, O., & Abugohar, M. (2023). Flipped learning in ELT: Experiences from Oman. Journal of Nusantara Studies, 8(2), 180-200. http://dx.doi.org/10.24200/jonus.vol8iss2pp180-20

Effect of thermal energy storage in energy consumption required for air conditioning system in office building under the african mediterranean climate

In the African Mediterranean countries, cooling demand constitutes a large proportion of total electrical demand for office buildings during peak hours. The thermal energy storage systems can be an alternative method to be utilized to reduce and time shift the electrical load of air conditioning from on-peak to off-peak hours. In this study, the Hourly Analysis Program has been used to estimate the cooling load profile for an office building based in Tripoli weather data conditions. Preliminary study was performed in order to define the most suitable operating strategies of ice thermal storage, including partial (load leveling and demand limiting), full storage and conventional A/C system. Then, the mathematical model of heat transfer for external ice storage would be based on the operating strategy which achieves the lowest energy consumption. Results indicate that the largest rate of energy consumption occurs when the conventional system is applied to the building, while the lowest rate of energy consumption is obtained when the partial storage (demand limiting 60%) is applied. Analysis of results shows that the new layer of ice formed on the surface of the existing ice lead to an increase of thermal resistance of heat transfer, which in return decreased cooling capacity

Effect of thermal energy storage in energy consumption required for air conditioning system in office building under the african mediterranean climate

In the African Mediterranean countries, cooling demand constitutes a large proportion of total electrical demand for office buildings during peak hours. The thermal energy storage systems can be an alternative method to be utilized to reduce and time shift the electrical load of air conditioning from on-peak to off-peak hours. In this study, the Hourly Analysis Program has been used to estimate the cooling load profile for an office building based in Tripoli weather data conditions. Preliminary study was performed in order to define the most suitable operating strategies of ice thermal storage, including partial (load leveling and demand limiting), full storage and conventional A/C system. Then, the mathematical model of heat transfer for external ice storage would be based on the operating strategy which achieves the lowest energy consumption. Results indicate that the largest rate of energy consumption occurs when the conventional system is applied to the building, while the lowest rate of energy consumption is obtained when the partial storage (demand limiting 60%) is applied. Analysis of results shows that the new layer of ice formed on the surface of the existing ice lead to an increase of thermal resistance of heat transfer, which in return decreased cooling capacity

Solar energy contribution to the energy demand for air conditioning system in an office building under tripoli climate conditions

The feasibility of solar assisted air-conditioning in an office building under Tripoli weather conditions is investigated in this paper. A single-effect lithium bromide absorption cycle powered by means of flat-plate solar collectors was modeled in order to predict the potential of the solar energy share. The cooling load profile was generated by using a detailed hourly based program and typical meteorological year for Tripoli. System performance and solar energy fraction were calculated by varying two major parameters (collector's slope angle and collector area). The maximum solar fraction of 48% was obtained by means of 1400 m(2) of collector surface area. Analysis of results showed that, besides the collector surface area, the main factors affecting the solar fraction were the local weather conditions (intensity of incident solar radiation) and the time of day when the plant was operated

Solar energy contribution to the energy demand for air conditioning system in an office building under tripoli climate conditions

The feasibility of solar assisted air-conditioning in an office building under Tripoli weather conditions is investigated in this paper. A single-effect lithium bromide absorption cycle powered by means of flat-plate solar collectors was modeled in order to predict the potential of the solar energy share. The cooling load profile was generated by using a detailed hourly based program and typical meteorological year for Tripoli. System performance and solar energy fraction were calculated by varying two major parameters (collector's slope angle and collector area). The maximum solar fraction of 48% was obtained by means of 1400 m(2) of collector surface area. Analysis of results showed that, besides the collector surface area, the main factors affecting the solar fraction were the local weather conditions (intensity of incident solar radiation) and the time of day when the plant was operated

Electron-Promoted Desorption from Water Ice Surfaces: Neutral Gas Phase Products

Electron-promoted desorption (EPD) from compact amorphous solid water (c-ASW) has been studied. Low-energy electron bombardment with 200–300 eV electrons leads to H2O depletion, as monitored by reflection–absorption infrared spectroscopy (RAIRS) of the remaining c-ASW film. Cross sections for H2O depletion were calculated to be in the range from 1.6 ± 1.0 × 10–16 to 5.2 ± 3.0 × 10–16 cm2. However, mass spectrometric measurements identify a major component of the desorbing material as H2, which appears with kinetics similar to those for H2O loss. Molecular H2O is observed as a minor desorption product in the gas phase

Peeling the astronomical onion

Water ice is the most abundant solid in the Universe. Understanding the formation, structure and multiplicity of physicochemical roles for water ice in the cold, dense interstellar environments in which it is predominantly observed is a crucial quest for astrochemistry as these are regions active in star and planet formation. Intuitively, we would expect the mobility of water molecules deposited or synthesised on dust grain surfaces at temperatures below 50 K to be very limited. This work delves into the thermally-activated mobility of H2O molecules on model interstellar grain surfaces. The energy required to initiate this process is studied by reflection-absorption infrared spectroscopy of small quantities of water on amorphous silica and highly oriented pyrolytic graphite surfaces as the surface is annealed. Strongly non-Arrhenius behaviour is observed with an activation energy of 2 kJ mol-1 on the silica surface below 25 K and 0 kJ mol-1 on both surfaces between 25 and 100 K. The astrophysical implication of these results is that on timescales shorter than that estimated for the formation of a complete monolayer of water ice on a grain, aggregation of water ice will result in a non-uniform coating of water, hence leaving bare grain surface exposed. Other molecules can thus be formed or adsorbed on this bare surface