Effects of mist fractions on heat transfer characteristics in a rotating roughened cooling passage

This paper investigates the effects of the mist fractions on heat transfer characteristics applied on a rotating U-channel with inclined ribs at an angle of 45°. This study has been conducted on five different mist percentages from 1 to 5 with a 1% increment at each step, and all of the cases have been investigated for Reynolds number values of 5000, 10000, 25000 and 40000. The numerical results obtained from the application of RNG k-ε turbulence model with enhanced-wall function were in good agreement with the experimental data of the smooth and ribbed channels both with and without mist addition. Results also demonstrated a 300% increase in the flow temperature difference and a noticeable increase in Nusselt number at each bend region and at the downstream of the leading edge around 25% and 110% respectively, at high mist fraction (5%); when compared with the case where only air was used. With %5 mist addition, the convective efficiency also reaches approximately 69%

Performance and Emissions Analysis of N-Butanol Blended with Gasoline in Spark Ignition Engine

The power developed by an internal-combustion engine depends upon the fuel used for combustion. Fuels commonly used in internal combustion engines are derived from crude oil, which are depleting and are important sources of air pollution. In this study, n-butanol was used as an additive with gasoline as fuel in spark ignition engine. N-butanol exhibits good burning characteristics, contain oxygen, reduces some exhaust emissions and as well, has energy density and octane rating close to that of gasoline. The various blend rates (4, 8, 12, 16 and 20 percent by volume) were used in the engine performance analysis using a TD110-115 single cylinder, four-stroke air-cooled spark ignition engine test rig, under different loading conditions. An SV-5Q automobile exhausts gas analyzer was used to measure the concentration of gaseous emissions such as unburnt hydrocarbon (UHC), carbon monoxide (CO), and carbon dioxide (CO2) from the engine tail pipe. The results of engine performance showed reduction in the exhaust temperature was observed for the blends than to that of gasoline. It was observed that all the blends improved the brake thermal efficiency and exhibited high fuel consumption, lower specific energy consumption and lower emissions than gasoline. All the blends performed satisfactorily on spark-ignition engine without engine modification

Flow structure and heat transfer of jet impingement on a rib-roughened flat plate

The jet impingement technique is an effective method to achieve a high heat transfer rate and is widely used in industry. Enhancing the heat transfer rate even minimally will improve the performance of many engineering systems and applications. In this numerical study, the convective heat transfer process between orthogonal air jet impingement on a smooth, horizontal surface and a roughened uniformly heated flat plate is studied. The roughness element takes the form of a circular rib of square cross-section positioned at different radii around the stagnation point. At each location, the effect of the roughness element on heat transfer rate was simulated for six different heights and the optimum rib location and rib dimension determined. The average Nusselt number has been evaluated within and beyond the stagnation region to better quantify the heat transfer advantages of ribbed surfaces over smooth surfaces. The results showed both flow and heat transfer features vary significantly with rib dimension and location on the heated surface. This variation in the streamwise direction included both augmentation and decrease in heat transfer rate when compared to the baseline no-rib case. The enhancement in normalized averaged Nusselt number obtained by placing the rib at the most optimum radial location R/D = 2 was 15.6% compared to the baseline case. It was also found that the maximum average Nusselt number for each location was achieved when the rib height was close to the corresponding boundary layer thickness of the smooth surface at the same rib position

An Improved Slant Path Attenuation Prediction Method in Tropical Climates

An improved method for predicting slant path attenuation in tropical climates is presented in this paper. The proposed approach is based on rain intensity data R_0.01 (mm/h) from 37 tropical and equatorial stations; and is validated by using the measurement data from a few localities in tropical climates. The new method seems to accurately predict the slant path attenuation in tropical localities, and the comparative tests seem to show significant improvement in terms of the RMS of the relative error variable compared to the RMS obtained with the SAM, Crane, and ITU-R prediction models

Enriching Information Security via Hybrid of New Expand Rivest Shamir Adleman and Data Encryption Standard Cryptosystem

Cryptography system gives security services ability to protect information from people who are authorized to use it. This research introduces elevated information security system via hybrid of new expand Rivest Shamir Adleman (RSA) and data encryption standard (DES) cryptosystem using appropriate standard lgorithms. An Expand Algorithm (ERSA) algorithm Key cryptosystem based on nth large prime number system was introduced. Then a hybrid between the Expand Algorithm (ERSA) with Data Encryption Standard (DES) was applied using four randomly selected variables, each generated from large factor of “N” prime numbers. The information undergoes a cypher text-decryption process which provides strong security and uphold high information confidentiality and integrity of data. Results showed that the use of ERSA and DES algorithm reduced the key generation period and its complexity analysis of encryption and decryption are stronger, unlike the application of traditional RSA algorithm

Insulin, estradiol levels and body mass index in pre- and post-menopausal women with breast cancer

AbstractBreast cancer is the most common cancer among women where it is associated with considerable morbidity and mortality. The aim of this study was to investigate the association between insulin, estradiol levels and body mass index (BMI) as risk factors for breast cancer. Methods: 80 women newly diagnosed with breast cancer stage I–III invasive breast cancer, were selected randomly and divided in two groups: 40 pre-menopausal aged 26–46 years and 40 post-menopausal aged 52–90 years. Radioimmunoassay used for serum insulin levels measurement, ELISA was used for estradiol levels and BMI calculated by weight (kg)/height (m2). Results: Insulin levels in premenopausal (16.6 ± 10.5) and postmenopausal (17.9 ± 8.8); breast cancer patients showed increasing pattern from the normal levels (4.0–16.0 μIU/ml). While, the levels of estradiol in premenopausal (233 ± 173) and postmenopausal, (549 ± 468); estradiol level in postmenopausal was higher than normal level (50–300 ng/ml), its level showed significantly increase in postmenopausal breast cancer (P.Value = 0.001). Conclusion: Insulin levels increased in pre- and post-menopausal breast cancer patients while estradiol levels do not showed association with premenopausal breast cancer. High BMI, high insulin and estradiol levels in post-menopausal women may be considered as risk factors for breast cancer

Kuwaiti EFL Students’ Perceptions of the Effectiveness of the Remedial English Course 099 at the College of Technological Studies

The study aims to evaluate the English remedial course 099 taught in the College of Technological Studies (PAAET) as part of the English program which disseminates English Language Skills to EFL students studying at this college. This study is expected to provide sufficient information to policymakers and educators involved with this program at all levels, with the intention to help them evaluate this course and make useful decisions to improve English Language Teaching in order to combat the deficiency in the English language suffered by college students in Kuwait. A number of 155 students participated in a questionnaire of 15 statements divided into four areas: reading, grammar, writing, and speaking skills. The findings of the study showed that most EFL students benefited from the English course 099, and their language skills were improved. However, there were some drawbacks and weaknesses of the program in terms of learners’ assessments and follow up. The significance of the study arises from the fact that it would enable decision-makers and course evaluators to pinpoint the strengths and weaknesses of the course and hence find ways to improve it

Dermatological Lesions of Cholesterol Embolization Syndrome and Kaposi Sarcoma Mimic Primary Systemic Vasculitis: Case Report Study

Primary systemic vasculitis can present with a wide spectrum of manifestations ranging from systemic non-specific features such as fever, malaise, arthralgia, and myalgia to specific organ damage. We describe two cases of cholesterol embolization syndrome and Kaposi sarcoma mimicking primary systemic vasculitis, both of which were characterized by features such as livedo reticularis, blue toe syndrome, a brown, purpuric skin rash, and positive p-ANCA associated with Kaposi sarcoma. Establishing the right diagnosis was challenging, and thus we aim in this study to highlight the possible ways to distinguish them from primary systemic vasculitis. Keywords: Dermatological lesions, Cholesterol embolization syndrome, Kaposi sarcoma, vasculitis mimic

The impact of the internet of things on information institutions from the perspective of library employees

The present paper addresses the role of the Internet of Things applications in supporting knowledge management activities in information organizations and so their services improve. To achieve this objective, the research adopts the descriptive approach through the investigation and analysis of the intellectual outcome published in the Arab and foreign countries to identify the relationship between the Internet of Things and knowledge management activities in information institutions. The results indicated that information institutions benefited from the Internet of things in tracking all the physical and intangible entities in these institutions and defining their locations in case of loss or replacement. Moreover, they could define the numbers of visitors, peak hour and the most used sources. Hence, they offered fast and interactive services that comply with the aspirations of the beneficiaries. The research recommends that various information institutions should take the initiative to benefit from the Internet of things applications that fulfill the new requirements of their beneficiaries