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يتناول البحث التحليل المبدئي النظري لتأثيرات الصدمات خارجية المنشأ وداخلية المنشأ على اقتصاديات الحج والعمرة والزيارة. وعبر استخدام منهج الإستقراء النظري والتحليل المقاصدي النظري الشرعي بالإضافة إلى المنهج النمذجي النظري لمتجهة الإنحدار الذاتي البنيوي، سعى البحث إلى دراسة نظرية للزيارة التعبدية، وعرض تفسير إفتراضي لتقلبات الدخل في قطاع الزيارة. تسمح هذه النمذجة برصد تأثيرات الصدمات البنيوية السالبة، وذلك باعتبار متغيرات تؤثر على دخل أم القرى، منها على وجه الخصوص حجم الاستثمار في قطاع الزيارة والذي يؤثر في الطاقة الإستعابية للفنادق، وأعداد الزائرين من العالم والذي يتأثر بتكلفة الحج و/أو العمرة المرتبطة مبدئيا بمؤشر الأسعار في الحرمين. وكذلك نفقة كل الزائرين التي تتم خلال زيارتهم، والتي تتغير تبعا لدخل الزوار من خارج المملكة ولدخل الزوار من داخل المملكة. كما نأخذ بعين الإعتبار مؤشرات تعكس الأزمات الإقتصادية والأمنية في بلاد الحرمين وفي غيرها من بلدان العالم، بالإضافة إلى مؤشرات حدوث الأوبئة أو الأمراض المعدية البارزة حول العالم مثل ما حدث مع وباء كورونا 19 الذي انتشر انتشارا واسعا عبر العالم. وبسبب هذه الجائحة العالمية سجل موسم حج 1441 هـ (يونيو 2020م) عددا صغيرا من حجاج الداخل فقط بحوالي 10000 في حين أن المتوقع دون الوباء أن يصل عدد الحجاج الى 2.5 مليون. وباستخدام نظرية المقاصد الشرعية في حفظ الدين والنفس والمال والعدل، ثم عبر النمذجة النظرية للصدمات البنيوية وما تفرزه من تفاعلات، يمكن الوصول إلى تصور واضح ووضع سياسة متكاملة للتعامل مع أزمات الأوبئة وما شابهها من مخاطر تؤثر على حياة الفرد المسلم في سفره من بيته إلى بيت الله في الحرم المكي وإلى زيارة الحرم المدني.

The paper aims to analyze the current account of the Saudi economy using an intertemporal modeling and tested by the structural VAR methodology. By deriving the long-run current account to GDP ratio, we analyze the impacts of global and local shocks on the current account. Considering that the Saudi economy is linked to international demand for oil products and domestic demand on consumer goods and technological products, the variances in the current account and output are inevitably influenced by international shocks. The findings indicate that the long-run impact of local shocks on the current account variance exceeds by 3.92 percent its impact on the output variance, reflecting the explanation power of local dynamic shock on the current account growth. Most of the previous papers suggest that the local impact dominates the international one (Souki and Enders, 2008), and few papers advocate that the global impact exceeds the domestic effect Hoffmann (2013). The shocks analysis on the Saudi current account exhibits the relative dominance of the global markets shocks, but local and mainly supply shocks have significant impacts on the current account, referring to a dual local and global influence. Keywords: Current account, Intertemporal modeling, Shocks, SVAR Model, KSA

Network intrusion detection system (NIDS) has become a vital tool to protect information and detect attacks in computer networks. The performance of NIDSs can be evaluated by the number of detected attacks and false alarm rates. Machine learning (ML) methods are commonly used for developing intrusion detection systems and combating the rapid evolution in the pattern of attacks. Although there are several methods proposed in the state-of-the-art, the development of the most effective method is still of research interest and needs to be developed. In this paper, we develop an optimized approach using an extreme gradient boosting (XGB) classifier with correlation-based feature selection for accurate intrusion detection systems. We adopt the XGB classifier in the proposed approach because it can bring down both variance and bias and has several advantages such as parallelization, regularization, sparsity awareness hardware optimization, and tree pruning. The XGB uses the max-depth parameter as a specified criterion to prune the trees and improve the performance significantly. The proposed approach selects the best value of the max-depth parameter through an exhaustive search optimization algorithm. We evaluate the approach on the UNSW-NB15 dataset that imitates the modern-day attacks of network traffic. The experimental results show the ability of the proposed approach to classifying the type of attacks and normal traffic with high accuracy results compared with the current state-of-the-art work on the same dataset with the same partitioning ratio of the test set. [ABSTRACT FROM AUTHOR]

Copyright of Al-Mustansiriyah Journal of Science is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Personalized trip recommendation attempts to recommend a sequence of Points of Interest (POIs) to a user. Compared with a single POI recommendation, the POIs sequence recommendation is challenging. There are only a couple of studies focusing on POIs sequence recommendations. It is a challenge to generate a reliable sequence of POIs. The two consecutive POIs should not be similar or from the same category. In developing the sequence of POIs, it is necessary to consider the categories of consecutive POIs. The user with no recorded history is also a challenge to address in trip recommendations. Another problem is that recommending the exact and accurate location makes the users bored. Looking at the same kind of POIs, again and again, is sometimes irritating and tedious. To address these issues in recommendation lies in searching for the sequential, relevant, novel, and unexpected (with high satisfaction) Points of Interest (POIs) to plan a personalized trip. To generate sequential POIs, we will consider POI similarity and category differences among consecutive POIs. We will use serendipity in our trip recommendation. To deal with the challenges of discovering and evaluating user satisfaction, we proposed a Serendipity-Oriented Personalized Trip Recommendation (SOTR). A compelling recommendation algorithm should not just prescribe what we are probably going to appreciate but additionally recommend random yet objective elements to assist with keeping an open window to different worlds and discoveries. We evaluated our algorithm using information acquired from a real-life dataset and user travel histories extracted from a Foursquare dataset. It has been observationally confirmed that serendipity impacts and increases user satisfaction and social goals. Based on that, SOTR recommends a trip with high user satisfaction to maximize user experience. We show that our algorithm outperforms various recommendation methods by satisfying user interests in the trip. [ABSTRACT FROM AUTHOR]

Origanum majorana L. (O.m.L.) has a high concentration of phenolic and flavonoids compounds like protocatechuic acid, caffeic acid and rosmarinic acid. The experimental treatments were designed to investigate of adding O.m.L. as a raw powder (0.1 and 0.2%, P1 and P2, respectively) and O.m.L. oil extract (0.1% and 0.2%, O1 and O2, respectively). Control treatment was as Tris-based extender and its effect on some Iraqi Awassi ram semen trails after preservation for different intervals including cooling storage at 5°C for 0, 24, 48, 72 hrs and cryopreservation at liquid nitrogen (-196°C) for one week. This study was conducted at ruminants researches satiation/Ministry of Agriculture, Iraq (Agargof, 25 km west of Baghdad) four local's improved Iraqi Awassi rams ages 2-2.5 years were selected and trained to collect semen by artificial vagina during 4 weeks as two ejaculates/ram/week. The study was carried out from the September to December, 2020. Raw powder treatment (P2) was showed a significant improvement (P<0.01) in motility percentage. On the other side, P2 was showed a significant (Pd"0.01) decrease of Abnormal, dead and acrosomal defect percentage compared with other experimental treatments and control groups after 72 hours at 5°C and post cryopreservation for one week. In conclusion, adding of 0.2% O.m.L. raw powder to Tris-based extender was recorded a good role to improve most of studied semen traits, where semen preserving at 5°C for (0, 24, 48, 72) hrs and one-week post cryopreservation in liquid nitrogen. [ABSTRACT FROM AUTHOR]

Impacting droplet on a hydrophobic surface is investigated and droplet size effect on impacting properties is examined. Liquid pressure variation inside droplet is numerically simulated in the impacting and rebounding periods. Droplet motion on impacted hydrophobic surface is monitored using a high-speed recording system. We showed that predictions and high-speed data for droplet shape and geometric features appear to be almost identical in the spreading and retraction of the droplet on sample surface. Increased volume of droplet gives rise to the peak pressure enhancement in droplet liquid during impact. The maximum droplet height remains larger for large volume droplets in both spreading and retraction cycles. Increasing size of droplet enlarges the wetting diameter on the impacted surface during droplet deformation on sample surfaces. The rate of peak velocity of the spreading surface of the droplet is faster for larger droplets as compared to that corresponding to small droplets. The ratio of spreading period over the retraction period of the droplet becomes small for droplets with small size. [ABSTRACT FROM AUTHOR]

Summary: The self‐cleaning of surfaces via impacting water droplets is examined pertinent to solar energy applications. The mechanism of spreading and retraction of the impacting droplet onto the dust and cleaned hydrophobic surfaces is considered in the analysis. The spreading factor of the impacting droplet is formulated incorporating the energy balance on the hydrophobic surface. High‐speed photography is used to monitor the impacting droplet behavior. The functionalized silica particles coating is introduced towards generating hydrophobic wetting state on the glass surfaces. Environmental dust particles are characterized prior to self‐cleaning impacting tests. It is found that spreading rate predicted for the impacting droplet agrees well with that obtained from the experiments. The droplet Weber number incorporated in the experiments does not result in droplet breaking on the surface upon impacting. The dusts are dissimilar in shapes and consist of several elements. Impacting droplet gives rise to cloaking of the dust on the surface during spreading and retraction. Almost all the dusts are removed from the surface through the impacting droplets; however, few dust residues are left on the impacting surface, which cover only 0.03% of the total surface area. Hence, we have demonstrated that self‐cleaning of a surface can be achieved by an impacting droplet for renewable energy applications. [ABSTRACT FROM AUTHOR]

Copyright of Arab Gulf Journal of Scientific Research is the property of Arabian Gulf University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, the impact mechanisms of a water droplet on hydrophobized micro-post array surfaces are examined and the influence of micro-post arrays spacing on the droplet behavior in terms of spreading, retraction, and rebounding is investigated. Impacting droplet behavior was recorded using a high-speed facility and flow generated in the droplet fluid was simulated in 3D geometry accommodating conditions of the experiments. Micro-post arrays were initially formed lithographically on silicon wafer surfaces and, later, replicated by polydimethylsiloxane (PDMS). The replicated micro-post arrays surfaces were hydrophobized through coating by functionalized nano-silica particles. Hydrophobized surfaces result in a contact angle of 153° ± 3° with a hysteresis of 3° ± 1°. The predictions of the temporal behavior of droplet wetting diameter during spreading agree with the experimental data. Increasing micro-post arrays spacing reduces the maximum spreading diameter on the surface; in this case, droplet fluid penetrated micro-posts spacing creates a pinning effect while lowering droplet kinetic energy during the spreading cycle. Flow circulation results inside the droplet fluid in the edge region of the droplet during the spreading period; however, opposing flow occurs from the outer region towards the droplet center during the retraction cycle. This creates a stagnation zone in the central region of the droplet, which extends towards the droplet surface onset of droplet rebounding. Impacting droplet mitigates dust from hydrophobized micro-post array surfaces, and increasing droplet Weber number increases the area of dust mitigated from micro-post arrays surfaces. [ABSTRACT FROM AUTHOR]

Self-cleaning of surfaces becomes challenging for energy harvesting devices because of the requirements of high optical transmittance of device surfaces. Surface texturing towards hydrophobizing can improve the self-cleaning ability of surfaces, yet lowers the optical transmittance. Introducing optical matching fluid, such as silicon oil, over the hydrophobized surface improves the optical transmittance. However, self-cleaning ability, such as dust mitigation, of the oil-impregnated hydrophobic surfaces needs to be investigated. Hence, solution crystallization of the polycarbonate surface towards creating hydrophobic texture is considered and silicon oil impregnation of the crystallized surface is explored for improved optical transmittance and self-cleaning ability. The condition for silicon oil spreading over the solution treated surface is assessed and silicon oil and water infusions on the dust particles are evaluated. The movement of the water droplet over the silicon oil-impregnated sample is examined utilizing the high-speed facility and the tracker program. The effect of oil film thickness and the tilting angle of the surface on the sliding droplet velocity is estimated for two droplet volumes. The mechanism for the dust particle mitigation from the oil film surface by the sliding water droplet is analyzed. The findings reveal that silicon oil impregnation of the crystallized sample surface improves the optical transmittance significantly. The sliding velocity of the water droplet over the thick film (~700 µm) remains higher than that of the small thickness oil film (~50 µm), which is attributed to the large interfacial resistance created between the moving droplet and the oil on the crystallized surface. The environmental dust particles can be mitigated from the oil film surface by the sliding water droplet. The droplet fluid infusion over the dust particle enables to reorient the particle inside the droplet fluid. As the dust particle settles at the trailing edge of the droplet, the sliding velocity decays on the oil-impregnated sample. [ABSTRACT FROM AUTHOR]

Water droplet impacting onto a hydrophobic surface is considered and the influence of the surface wetting state on the droplet dynamics is examined. Pressure variation in the impacting droplet is predicted numerically using the level set model. The droplet spreading and the retraction on the hydrophobic surface are assessed for various wetting states of the hydrophobic surface. Experiment is carried out to validate the predictions of the droplet shape and the restitution coefficient. It is found that predictions of impacting droplet shape and the restitution coefficient agree with those obtained from the experiment. The local pressure peaks formed in the droplet fluid, particularly in the retraction period, causes alteration of the droplet vertical height and the shape. Droplet spreading is influenced by the wetting state of the hydrophobic surface; hence, increasing contact angle of the hydrophobic surface lowers the spreading diameter of the droplet on the surface. The transition time of the droplet changes with the wetting state of the hydrophobic surface such that increasing droplet contact angle reduces the transition time of the droplet on the surface. The droplet remains almost round after the first bounding for large contact angle hydrophobic surface. [ABSTRACT FROM AUTHOR]

A water droplet behavior on a hydrophobic surface is examined relevant to the dust particles removal from the surface. Surface crystallization of polycarbonate is realized in acetone bath and the resulting surface is coated by the functionalized nano-size silica particles towards reducing contact angle hysteresis. This arrangement provides droplet rolling/sliding on the hydrophobic surface. Droplet translational velocity is formulated and predictions are compared with those resulted from the high speed recorded data. Influence of surface inclination angle on droplet dynamics is investigated and the dust removal mechanism on the inclined surface is analyzed. It is found that predictions of droplet translational velocity agree well with those obtained from the experiment. Droplet rolling dominates over sliding on the inclined surface and droplet sliding velocity remains almost 10% of the droplet translational velocity. The main mechanism for the dust particles removal is associated with the droplet fluid cloaking of the dust particles during its transition on the hydrophobic surface. Droplet acceleration, due to increased surface inclination angle, has effect on the rate of dust particles removal from the surface, which is more apparent for large droplet volumes. Increasing droplet acceleration improves the coverage area of the clean surface. [ABSTRACT FROM AUTHOR]

Environmental dusts settle on surfaces and influence the performance of concentrated solar energy harvesting devices, such as aluminum troughs. The characteristics of environmental dust and the effects of mud formed from the dust particles as a result of water condensing in humid air conditions on an aluminum wafer surface are examined. The dissolution of alkaline and alkaline earth compounds in water condensate form a chemically active mud liquid with pH 8.2. Due to gravity, the mud liquid settles at the interface of the mud and the aluminum surface while forming locally scattered patches of liquid films. Once the mud liquid dries, adhesion work to remove the dry mud increases significantly. The mud liquid gives rise to the formation of pinholes and local pit sites on the aluminum surface. Morphological changes due to pit sites and residues of the dry mud on the aluminum surface lower the surface reflection after the removal of the dry mud from the surface. The characteristics of the aluminum surface can address the dust/mud-related limitations of reflective surfaces and may have implications for the reductions in the efficiencies of solar concentrated power systems. [ABSTRACT FROM AUTHOR]

The dynamic motion of a water droplet on an inclined hydrophobic surface is analyzed with and without environmental dust particles on the surface. Solution crystallization of a polycarbonate surface is carried out to generate a hydrophobic surface with hierarchical texture composed of micro/nanosize spheroids and fibrils. Functionalized nanosize silica particles are deposited on the textured surface to reduce contact angle hysteresis. Environmental dust particles are collected and characterized using analytical tools prior to the experiments. The droplet motion on the hydrophobic surface is assessed using high-speed camera data, and then, the motion characteristics are compared with the corresponding analytical results. The influence of dust particles on the water droplet motion and the amount of dust particles picked up from the hydrophobic surface by the moving droplet is evaluated experimentally. A 40 μL droplet was observed to roll on the hydrophobic surface with and without dust particles, and the droplet slip velocity was lower than the rotational velocity. The rolling droplet removes almost all dust particles from the surface, and the mechanism for the removal of dust particles from the surface was determined to be water cloaking of the dust particles.