Improving Local Asphalt Pavement with Nano-CaCO3

During the last two decades, a significant increase in the number of vehicles in Baghdad city related to uncontrolled axle loading, hot climate summer, lack of asphalt pavement maintenance, and heavy traffic has combined and led to severe consequences in the paved road. Therefore, asphalt cement enhancement and improvement is the first key to solving and correcting these issues. Recently, nanomaterial has gained considerable recognition in asphalt technology as the new modifier due to the homogeneity, dispersion, and large surface area in contact with asphalt particles. This paper investigates the effect of adding nano CaCO3 into asphalt cement. The laboratory experiment included 40-50 penetration grades prepared with different content 1, 3,5, and 7% to quantify the potential benefit of a physical test of Asphalt, Marshall properties, and tensile strength of hot mix asphalt. The testing result indicated that nano-CaCO3 modified asphalt with a 5% improved penetration grade and softening point. On the other hand, Marshall Stability increased to 14.38 kN. Furthermore, tensile strength increased to 1121 KPa due to the stuffing effect, increased adhesion that increased the resistance of asphalt mixture towards permanent deformation during the hot summer climate in Iraq

Computational Simulation for the Fragmentation Regimes by Using Droplet Breakup Model

لا توجد محاولات بحثية رقمية لمحاكاة آلية تكسر القطيرات في عملية تطوير الرذاذ. على وجه الخصوص، يشير العمل الموصوف هنا إلى دراسة وقياس تفكك نظام القطيرات وآثارها على سلوك الرذاذ. مع هذا الغرض، يتم تنفيذ نتائج معاملات النماذج، بناءً على نموذج تكسير القطيرات المقترح من قبل Reitz و Diwakar[1] وحسابات فيض الزخم momentum flux. يتم تخزين المعاملات المستخدمة في نموذج تقسيم القطيرات في الشفرة كخصائص. ويتم حفظ هذه الخصائص في كل خلية حساب. المعاملات هي عدد ويبر، وزمن التكسير وقطر القطرة المستقر. حيث يتم تطبيق المحاكاة الرقمية كأسلوب Eulerian-Eulerian. وتستخدم نظرية زخم الرذاذ للمرحلة السائلة. وأخيرا يتم تنفيذ الدراسة في نموذج للتحقق في الفوائد المحتملة لنموذج تكسير القطيرات. وبينت المقارنة تطابق جيد للنتائج العددية مع البيانات التجريبية لتغلغل الرذاذ.There are no numerical research paper attempts to simulate the break-up mechanism of droplets in the spray development.  In particular, the work described here refers to study and quantify the break-up of droplets regime and their effects on the spray behavior. With this purpose, the model parameters results, based on droplet break-up model proposed by Reitz and Diwakar [1] and momentum flux calculations are performed. The parameters that are used in the droplet break-up model are stored in the code as properties. These properties are saved in every computation cell. The parameters are Weber number, break-up time and stable droplet diameter. The numerical simulation is implemented as Eulerian-Eulerian approach. The spray moments theory is used for the liquid phase. Finally the study is implemented in a conceptual model to investigate the possible benefits of the droplet break-up model. A good agreement for the numerical results are compared with the experimental data for the spray tip penetration

RHEOLOGICAL PROPERTIES OF IRAQI ASPHALT BINDERS MEASURED USING SUPERPAVE SYSTEM AND SHELL SOFTWARE

The performance grading system (superpave) has provided means to incorporate binder characteristics with pavement failure types. It’s a comprehensive system that relates climate, traffic conditions and aging with critical pavement distress. The objective of this paper is to develop an improved asphalt binder grading system for Iraq based on the principal of superpave. The country was divided into different zones according to the highest and lowest temperature ranges and traffic loading. The Performance graded binder proposed for each zone was compared with some States of USA that have same hot weather of Iraq by using Long Term Pavement Performance (LTPP v3.1) software. Iraqi asphalt samples were tested using the Superpave technology in Wisconsin University and the results were compared with those estimated using Shell pavement design software packages (BANDS 2) at different loading time and frequency. In general, the performance grade of binders produced from the three refineries in Iraq (Daurah, Basrah and Baiji) is PG 64-16. The m- value (slope of log creep stiffness versus log frequency curve at specified temperature) determined by DSR (Dynamic Shear Rheometer) and Shell software was compared

Effect of High RAP Content on Marshal Performance of Hot Asphalt Mixture for Surface and Binder Layers

Recently, the exhaustion of new aggregates and the rising price of " raw materials" have caused the increasing exploitation of "reclaimed asphalt pavement "(RAP) in pavement construction and rehabilitation. It is being reported that the usage of RAP does not only reduce the cost of pavement construction projects due to the less consumption of asphalt and aggregate but also saves land resources and greatly protects the environment, Where the same materials used in the construction of the original highway system can be reused to rebuild, repair and maintain it. Where appropriate, recycled Aggregates and other highway construction materials make a good economy; in the" environmental and engineering' sense, with supply limited and demand increasing, HMA producers have begun the use of "Reclaimed Asphalt Pavement" (RAP) as a value component of the" HMA." For this reason, there is renewed interest in increasing the amount of RAP used in hot mix asphalt (HMA). Although many factors affect the use of RAP in asphalt paving, the two main factors are "Economic savings " and " Environmental benefits." RAP is a useful alternative to raw materials. It reduces the use of virgin aggregates and the amount of "virgin asphalt binder required HMA productions, this study highlight how RAP impacts environmental and economic terms through the use of different percentages of RAP (10, 15, 20, and 25%) from the total weight of the mixture for the surface layer, and the change of (30, 40, 50, and 60%) of the total weight of the mixture for the binder layer used in the "HMA-RAP" composition that was heated at a temperature of “150°C” and then mixed with a total temperature of “170-180°C” plus asphalt at a temperature of “153°C” so the new mixing temperature, obtained at “148- 153 ° C" to obtain the ideal recovery of the reclamation, where the asphalt binder is restored rheological properties as this temperature is considered the recovery point of the asphalt binder. The results of mixing different ratios of RAP in the hot mixture showed that a large amount could be mixed in both layers and does not exceed (20%) in the surface layer and (50%) in the bond layer. This is because the Marshall stability was the highest possible during these ratios. As for increasing or decreasing these ratios, it led to a decrease in Marshall stability. The test results showed that with the increase of the amount of RAP in the mixture asphalt, the optimum value of the asphalt level (OAC) included in the asphalt mixture decreased as the percentage of asphalt used in the surface layer was reduced from (4.9 to 3.92%) When adding 20% of the RAP, and (4.6 to 2.3%) When adding (50%) of the RAP for the binder layer. This, in turn, leads to a decrease in the cost of asphalt, which is included in the asphalt mixture, and the results showed that the mixture stability to the influence of water, changes in temperature, and bonds between new materials (asphalt and aggregate) with RAP material was still good

Enhancement of Rutting Resistance for HMA Pavement Layers by Incorporating with SBS Modified Asphalt and A High Percentage of RAP

The loss of natural resources is one of the growing problems due to the inability to replace these resources on the one hand, and environmental pollution resulting from damage to asphalt pavements on the other hand. So the use of RAP in asphalt mixture has been promoted. The research addressed the inclusion of RAP in bulk and its effect on the resistance of asphalt mixtures to "RUTTING" as one of the most important problems. What mixtures are exposed to during high-temperature cycles where there are four different percentages of RAP (10, 15, 20, 25%), (30, 40, 50, 60%) and (40, 50, 60, 70%) For each of the three paving layers (surface, bond, base) respectively. Four samples were taken at three different temperatures (45, 55, and 70) degrees Celsius of asphalt mixtures for each of the three pavement layers. Various types of asphalt bonds have been used. To evaluate mixtures during the Hamburg Wheel Track test at different temperatures. The results indicated an improvement in the corrosion resistance of the mixture with the inclusion of RAP. The resistance of the asphalt mixture increased when SBS asphalt was used, which improved the mechanical properties of the asphalt mixtures. The experimental results of the Hamburg wheel test also showed a significant improvement in "Rutting Resistance" when RAP was added at its optimum value. For each of the three layers (surface, binder, base), the use of SBS modified asphalt reduces permanent deformation of the asphalt mixture

Modeling of Groundwater Potential Using Cloud Computing Platform: A Case Study from Nineveh Plain, Northern Iraq

Knowledge of the groundwater potential, especially in an arid region, can play a major role in planning the sustainable management of groundwater resources. In this study, nine machine learning (ML) algorithms—namely, Artificial Neural Network (ANN), Decision Jungle (DJ), Averaged Perceptron (AP), Bayes Point Machine (BPM), Decision Forest (DF), Locally-Deep Support Vector Machine (LD-SVM), Boosted Decision Tree (BDT), Logistic Regression (LG), and Support Vector Machine (SVM)—were run on the Microsoft Azure cloud computing platform to model the groundwater potential. We investigated the relationship between 512 operating boreholes with a specified specific capacity and 14 groundwater-influencing occurrence factors. The unconfined aquifer in the Nineveh plain, Mosul Governorate, northern Iraq, was used as a case study. The groundwater-influencing factors used included elevation, slope, curvature, topographic wetness index, stream power index, soil, land use/land cover (LULC), geology, drainage density, aquifer saturated thickness, aquifer hydraulic conductivity, aquifer specific yield, depth to groundwater, distance to faults, and fault density. Analysis of the contribution of these factors in groundwater potential using information gain ratio indicated that aquifer saturated thickness, rainfall, hydraulic conductivity, depth to groundwater, specific yield, and elevation were the most important factors (average merit \u3e 0.1), followed by geology, fault density, drainage density, soil, LULC, and distance to faults (average merit \u3c 0.1). The average merits for the remaining factors were zero, and thus, these factors were removed from the analysis. When the selected ML classifiers were used to estimate groundwater potential in the Azure cloud computing environment, the DJ and BDT models performed the best in terms of all statistical error measures used (accuracy, precision, recall, F-score, and area under the receiver operating characteristics curve), followed by DF and LD-SVM. The probability of groundwater potential from these algorithms was mapped and visualized into five groundwater potential zones: very low, low, moderate, high, and very high, which correspond to the northern (very low to low), southern (moderate), and middle (high to very high) portions of the study area. Using a cloud computing service provides an improved platform for quickly and cheaply running and testing different algorithms for predicting groundwater potential

Topographic and Clinical Characteristics of a Sample of Jordanian Students

Purpose: To screen for keratoconus (KC) and potential associated risk factors in a sample of medical students. Methods: This cross sectional study included 120 medical students studying at The University of Jordan. They were randomly selected from a total of 400 students. Participants responded by completing a self-administered questionnaire. Following initial clinical evaluation, corneal tomography images and indices were analyzed by an experienced ophthalmologist, after which the participants were classified into: normal, KC suspects and KC patients. Results: A total of 120 participants (mean age, 23.1 ±0.5 years) were included in this study, 70 (58.3%) were females and 50 (41.7%) were males. Two subjects had KC, demonstrating a prevalence of 1.7% while five (4.2%) participants showed at least two abnormal indices and were considered as KC suspects.Conclusion: the result of this study is similar to other studies conducted in the Middle East, which indicates a higher prevalence of KC than other western countries. Combined with the significantly impaired vision-related quality of life and the relatively young onset of disease, the burden of keratoconus represents a significant public health concern

Perspective Chapter: The Toxic Silver (Hg)

In the late 1950s, residents of a Japanese fishing village known as “Minamata” began falling ill and dying at an alarming rate. The Japanese authorities stated that methyl-mercury-rich seafood and shellfish caused the sickness. Burning fossil fuels represent ≈52.7% of Hg emissions. The majorities of mercury’s compounds are volatile and thus travel hundreds of miles with wind before being deposited on the earth’s surface. High acidity and dissolved organic carbon increase Hg-mobility in soil to enter the food chain. Additionally, Hg is taken up by areal plant parts via gas exchange. Mercury has no identified role in plants while exhibiting high affinity to form complexes with soft ligands such as sulfur and this consequently inactivates amino acids and sulfur-containing antioxidants. Long-term human exposure to Hg leads to neurotoxicity in children and adults, immunological, cardiac, and motor reproductive and genetic disorders. Accordingly, remediating contaminated soils has become an obligation. Mercury, like other potentially toxic elements, is not biodegradable, and therefore, its remediation should encompass either removal of Hg from soils or even its immobilization. This chapter discusses Hg’s chemical behavior, sources, health dangers, and soil remediation methods to lower Hg levels

Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey

Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020

Impact of opioid-free analgesia on pain severity and patient satisfaction after discharge from surgery: multispecialty, prospective cohort study in 25 countries

Background: Balancing opioid stewardship and the need for adequate analgesia following discharge after surgery is challenging. This study aimed to compare the outcomes for patients discharged with opioid versus opioid-free analgesia after common surgical procedures.Methods: This international, multicentre, prospective cohort study collected data from patients undergoing common acute and elective general surgical, urological, gynaecological, and orthopaedic procedures. The primary outcomes were patient-reported time in severe pain measured on a numerical analogue scale from 0 to 100% and patient-reported satisfaction with pain relief during the first week following discharge. Data were collected by in-hospital chart review and patient telephone interview 1 week after discharge.Results: The study recruited 4273 patients from 144 centres in 25 countries; 1311 patients (30.7%) were prescribed opioid analgesia at discharge. Patients reported being in severe pain for 10 (i.q.r. 1-30)% of the first week after discharge and rated satisfaction with analgesia as 90 (i.q.r. 80-100) of 100. After adjustment for confounders, opioid analgesia on discharge was independently associated with increased pain severity (risk ratio 1.52, 95% c.i. 1.31 to 1.76; P < 0.001) and re-presentation to healthcare providers owing to side-effects of medication (OR 2.38, 95% c.i. 1.36 to 4.17; P = 0.004), but not with satisfaction with analgesia (beta coefficient 0.92, 95% c.i. -1.52 to 3.36; P = 0.468) compared with opioid-free analgesia. Although opioid prescribing varied greatly between high-income and low- and middle-income countries, patient-reported outcomes did not.Conclusion: Opioid analgesia prescription on surgical discharge is associated with a higher risk of re-presentation owing to side-effects of medication and increased patient-reported pain, but not with changes in patient-reported satisfaction. Opioid-free discharge analgesia should be adopted routinely