Optimization of TiO2 thin film thickness for dye sensitized solar cell applications

Dye sensitized solar cells (DSSCs) rely on the absorption of photons by the dye molecules which are transported to the conduction band of the TiO2 electrode. The microstructure, energy gap and the absorption spectra of the TiO2 electrodes highly affects the efficiency of the cell. In this paper, the absorption spectra and energy gap has been studied by varying the thickness of the TiO2 paste. Nanocrystalline TiO2 thin films were deposited on ITO glass substrate with three different thickness (4.54μm, 7.12μm and 12.3μm) by using doctor blade method. After deposition all the samples were sintered at 450°C after deposition to enhance the particle bonding and for achieving better adhesion. The samples were characterized by UV-VIS spectra for determining the absorption spectra and Scanning Electron Microscopy (SEM) for investigating the thickness and the surface morphology. Fabricating the electrodes with different thickness showed significant changes in the energy gap and from the results it can be concluded that the energy gap increases with the increased thickness. The highest energy gap of 2.25ev and absorption 3.791 was achieved by 12.3μm thick sample. The absorption spectra also shows better absorption throughout the whole visible light range but the SEM images suggests that 12.3μm thick sample shows cracks all over the deposited region which will cause current leakage when the cell is assembled. Therefore, the optimum result was achieved by 7.12μm thick sample providing 1.9 ev energy gap and 3.91 absorption peak

Exceptional Points of Degeneracy in Periodic Coupled Waveguides and the Interplay of Gain and Radiation Loss: Theoretical and Experimental Demonstration

We present a novel paradigm for dispersion engineering in coupled transmission lines (CTLs) based on exceptional points of degeneracy (EPDs). We develop a theory for fourth-order EPDs consisting of four Floquet-Bloch eigenmodes coalescing into one degenerate eigenmode. We present unique wave propagation properties associated to the EPD and develop a figure of merit to assess the practical occurrence of fourth-order EPDs in CTLs with tolerances and losses. We experimentally verify for the first time the existence of a fourth EPD (the degenerate band edge), through dispersion and transmission measurements in microstrip-based CTLs at microwave frequencies. In addition, we report that based on experimental observation and the developed figure of merit, the EPD features are still observable in structures that radiate (leak energy away), even in the presence of fabrication tolerances and dissipative losses. We investigate the gain and loss balance regime in CTLs as a mean of recovering an EPD in the presence of radiation and/or dissipative losses, without necessarily resorting to Parity-Time (PT)-symmetry regimes. The versatile EPD concept is promising in applications such as high intensity and power-efficiency oscillators, spatial power combiners, or low-threshold oscillators and opens new frontiers for boosting the performance of large coherent sources

An investigation into solid waste problem in the Egyptian construction industry: A mini-review

Solid waste management (SWM) is one of the most critical global challenges nowadays. It has a severe negative effect on the triple bottom line of sustainability. Construction and demolition waste (CDW) contributes about 50% of the total global annual generated SW. In the particular case of the Middle East and North Africa (MENA) region including Egypt, the SW problem has become a major challenge, and the need to find sustainable solutions is overwhelming. However, the region faces several challenges that hinder the development of an effective and efficient SWM system. This has resulted in the predominance of unsustainable SWM practices such as indiscriminate disposals. The aim of this paper is to investigate the escalating problem of SW in the MENA region, while focusing on CDW in Egypt as a part of the total generated SW, by reviewing the most recent research papers, and technical and governmental reports on the SW problem. The main challenges towards effective and efficient SWM systems and recommendations for improvement are gathered in this study based on the explored literature. Findings from this study are expected to be beneficial to local and central governments, academics, construction industry practitioners, and policymakers contending with the problems of SW in the MENA region and especially CDW in Egypt

DC-SIGN Receptor Level in Rheumatoid Arthritis Patients in Baghdad; Serological study

التهاب المفاصل الروماتويدي هو أحد أمراض المناعة الذاتية الالتهابية الجهازية التي ترتبط ارتباطًا وثيقًا بتدمير الغضاريف والعظام. يعد DC-SIGN من مستقبلات C-type lectin receptors (CLRs) المهمة و يعبر على سطح الخلايا المتغصنة و البلعمية  و له  دور اساسي في تنظيم المناعة الفطرية والمكتسبة ،  كما يعمل كمستقبل للتعرف على الأنماط و ايضا كجزيئة التصاق. أثبتت الدراسات تورط الـ DC-SIGN في الفسيولوجية المرضية للالتهابات المزمنة، لذلك تم ربط علاقة الـ DC-SIGN بالعديد من امراض المناعة الذاتية، لذا قد تلعب عاملاً ومؤشرًا أساسيًا في التسبب وتطورمرض التهاب المفاصل الروماتويدي. لذا الغرض من هذه الدراسة هو تحديد المستوى المصلي للـ DC-SIGN في مرضى التهاب المفاصل الروماتويدي، وكذلك دراسة المستوى المصلي للـ DC-SIGN اعتماداً على الخصائص الديموغرافية للمرضى. شملت الدراسة خمسون مريضا عراقيا يعاني من التهاب المفاصل الروماتويدي، وتضمنت الدراسة ايضا عينة سيطرة لاشخاص اصحاء (تم التأكد عن طريق الفحوصات السريرية والمختبرية)، وتمت مطابقتهم حسب الجنس والعمر والعرق مع المرضى. تم حساب تركيز DC-SIGN في مصل المرضى ومقارنته بالسيطرة باستخدام اختبار ELISA وأظهرت النتائج زيادة معنوية في مستوى مصل DC-SIGN (12.047 ± 1.114 مقابل 6.863 ± 0.806 نانوغرام / مل) في مرضى التهاب المفاصل الروماتويدي مقارنة بالسيطرة. وعند ربط النتائج، تبين أن تركيز DC-SIGN في المصل لم يسجل فرقًا معنوياً بين الجنس والعمر وكذلك الحال لمجاميع الدم. و لتحديد تأثير الحالة العلاجية لمرضى التهاب المفاصل الروماتويدي على مستوى DC-SIGN ، وجد أن تركيز مستوى DC-SIGN كان أعلى في المرضى الغير المعالجين مقارنة بالمرضى المعالجين. و عندما أجريت دراسة على مرضى التهاب المفاصل الروماتويدي المصابين بـ SARS-CoV-2 ، لم يظهر مستوى مصل DC-SIGN في مرضى التهاب المفاصل الروماتويدي و المصابين بـ COVID-19 أي تغيير في تركيز DC-SIGN مقارنة بمرضى التهاب المفاصل الروماتويدي الغير مصابين.Rheumatoid arthritis (RA), is an autoimmune, and inflammatory disease that is closely related to the destruction of cartilage and bone. DC-SIGN are important types of C-type lectin receptors (CLRs), expressed on dendritic cells and macrophages, and have a central role in regulating innate and adaptive immunity, function as pattern recognition receptors, and as cell adhesion molecules. Recent evidence has demonstrated that DC-SIGN is involved in the pathophysiological of chronic inflammation, so DC-SIGN has been linked to several autoimmune and may play an essential indicator in the pathogenesis and progression of RA. Therefore, the purpose of this study is to determine the serum level of DC-SIGN in RA patients, as well as the level of DC-SIGN based on demographic characteristics. Fifty Iraqi RA patients were enrolled in the study, and a control sample of 38 healthy individuals (ascertain by laboratory and clinical tests) were included and matched by gender, age, and ethnicity with the patients. The DC-SIGN concentration was calculated in the patients’ serum and compared to control using the ELISA assay and the results revealed significantly increased serum level of DC-SIGN (12.047 ± 1.114 vs. 6.863 ± 0.806 ng/ml) was recorded in RA patients compared to controls. When correlating results, it was shown that the concentration of DC-SIGN in the serum did not record a significant difference between gender and age, as well as the blood groups. To determine the impact of the therapeutic status in RA patients on the DC-SIGN level, it was found that the concentration of DC-SIGN level was higher in untreated patients compared to treated patients. Regarding viral infection, when an investigation was conducted in RA patients infected with SARS-CoV-2, the serum level of DC-SIGN in RA patients with COVID-19 showed no change in concentrations compared to uninfected RA patients

Commercial wind turbines modeling using single and composite cumulative probability density functions

As wind turbines more widely used with newer manufactured types and larger electrical power scales, a brief mathematical modelling for these wind turbines operating power curves is needed for optimal site matching selections. In this paper, 24 commercial wind turbines with different ratings and different manufactures are modelled using single cumulative probability density functions modelling equations. A new mean of a composite cumulative probability density function is used for better modelling accuracy. Invasive weed optimization algorithm is used to estimate different models designing parameters. The best cumulative density function model for each wind turbine is reached through comparing the RMSE of each model. Results showed that Weibull-Gamma composite is the best modelling technique for 37.5% of the reached results

Factors Controlling the Development of Wine-Glass Forms in the Mountains of the Kurdistan Region, Iraq

The northern and northeastern parts of Iraq are mountainous areas and rugged topography with different erosional and morphological forms; among them are the wine-glass (erosional cirques) forms. They are developed in different shapes, sizes, and depths. In the outlets of the wine-glass forms; usually, alluvial fans are formed. The studied area is characterized by the presence of long and narrow anticlines with NW–SE trend that changes westward to E–W trend. The Cretaceous carbonate rocks form the main carapace of the majority of the mountains; however, locally Paleogene and/or Jurassic rocks form the carapace. In the core, rocks down to Devonian are exposed. In those anticlines where only Cretaceous rocks are exposed, no or very rarely wine-glass forms are developed. This is attributed to the Cretaceous carbonate rocks, which exist in huge thicknesses in many formations, with thickly bedded to massive nature and very hard erosion resisting rocks. Tens of the existing wineglass forms are studied to indicate the factors that control their development, which are the type of exposed rocks, their thicknesses, and hardness. To perform the aim of this study, different satellite imagery with different resolutions was used; besides using GIS technique and field check to improve the acquired date

Factors Controlling the Development of Straight Valleys and Streams in the Kurdistan Region, North and Northeast of Iraq

The Iraqi Kurdistan Region is a mountainous area with relief difference ranging from few hundred meters up to 3000 m, and locally more. Almost all of the mountains form anticlines that have NW–SE trend changing westwards of longitude to E–W. The carapace of the majority of the mountains is built up of Cretaceous rocks; however, some of them are of older rocks. Many of those anticlines are crossed by straight valleys and/or are crossed by streams and rivers which form again straight lines and almost coincide with regional lineaments, usually in N–S or NE–SW trend. The studied straight valleys are controlled, most probably by tectonic factors, therefore, exhibit special topographic forms, like straight lineaments crossing many successive anticlines, and also clear bending in some of the ridges in their crossing points to the valleys and/or streams. This paper aims to determine and discuss the factors that control the development of the straight valleys and/or lineaments. To achieve this aim, remote sensing and GIS techniques were followed, using Landsat, QuickBird images as well as geological maps of different scales, and different published articles

Sexual behaviour of pregnant women attending antenatal care clinic at Assiut Women's Health Hospital, Egypt

Background: The aim of the current study was to describe the knowledge, attitudes, beliefs and behavior of pregnant women regarding sexuality during pregnancy. Study was carried out at Women’s Health Hospital, Assiut University, Egypt.Methods: A cross-sectional study included pregnant women at different gestational ages between December 2016 and Jun 2017 recruited consecutively at the antenatal outpatient clinic of women’s Health Hospital at Assiut University. We used the Arabic version of the Female Sexual Function Index (Ar-FSFI) in the interview to evaluate the sexual functions or problems during the last month. The cut-off score used to indicate sexual dysfunction was 28.1. The obtained data were analyzed by means of SPSS software (version 22.0) and p<0.05 was taken as the significant level.Results: The study included 140 pregnant women at different ages and trimesters and also at different socio-economic states. Concerning the level of knowledge, the classification in recorded a mean score =11.91±4.05 which revealed a level of knowledge below average. Regarding the extent of beliefs in relation to sexuality during pregnancy, the mean score=2.72 of the respondents’ beliefs means that the impact of the beliefs regarding sexuality during pregnancy was weak among respondents. On assessing their perceptions about sexual intercourse during pregnancy, majority of them [130 (93.1%)] felt that sex have no negative impacts on pregnancy while 10 (6.9%) opined that sex during pregnancy had negative effects. Perceived negative effects of sex during pregnancy included vaginal bleeding and miscarriage.Conclusions: The low rate of sexual activity in our study, regardless question about the taboo of sexual intercourse during pregnancy, could be related to a cultural background in which women avoid speaking about their desires and sexual needs