development of non-petroleum binders derived from fast pyrolysis bio-oils for use in flexible pavement

Most bituminous adhesives or binders that are used for pavement materials are derived primarily from fossil fuels. Nevertheless, with petroleum oil reserves becoming depleted and the subsequent promotion to establish a bio-based economy, there is a drive to develop and produce binders from alternative sources, particularly from biorenewable resources. Recently, through the application of scientific research and development, a range of different vegetable oils have been investigated to determine their physical and chemical properties to study their applicability to be used as bio-binders in the pavement industry. Bio-binders can be utilized in three different ways to decrease the demand for fossil fuel based bituminous binders summarized as follows: (1) as a bitumen modifier (\u3c10% bitumen replacement), (2) as a bitumen extender (25% to 75% bitumen replacement), and (3) as a direct alternative binder (100% replacement). On the other hand, there has been no research conducted until now that studies the applicability of the utilization of bio-oils as a bitumen replacement (100% replacement) to be used in the pavement industry. The main objectives of this dissertation can be summarized as follows. First, the rheological properties of fast pyrolysis liquid co-products (bio-oils) were investigated to determine the heat pre-treatment/upgrading procedure required for developing bio-binders from bio-oils. The second objective included the modification of Superpave test procedure to comply with the properties of the developed bio-binders. Third, the chemical characterization of the developed bio-binders was studied in addition to the physical characterization. Fourth, the utilization of bio-oils as bio-binders in the pavement industry was explored through determining the temperature and shear susceptibilities of the developed bio-binders and comparing them with commonly used bitumen binders. Fifth, the temperature performance grades for the developed bio-binders were measured in addition to the determination of the mixing and the compaction temperatures. Sixth, the master curves for the developed bio-binders were studied and compared to commonly used bitumen binders. The overall conclusions about the applicability of using bio-oils as bio-binders in the pavement industry can be summarized as follows. First, the bio-oils cannot be used as bio-binders/pavement materials without any heat pre-treatment/upgrading procedure due to the presence of water and volatile contents in considerable amounts. The heat treatment/upgrading procedure for deriving bio-binders from bio-oils should be determined for each type of bio-oil separately due to the significant difference between the different types of bio-oils, e.g. the chemical composition, the process by which the bio-oils were derived, and the type of the biorenewable resource from which the bio-oils were derived. Second, the current testing standards and specifications, especially Superpave procedures, should be modified to comply with the properties of the bio-binders derived from bio-oils because of difference in temperature susceptibility and aging. Third, the temperature range of the viscous behavior for bio-oils may be lower than that of bitumen binders by about 30-40yC. Fourth, the rheological properties, i.e. temperature and shear susceptibilities, of the unmodified bio-binders derived from bio-oils vary in comparison to bitumen binders, but upon adding polymer modifiers, the rheological properties of these modified bio-binders change significantly. Fifth, the high temperature performance grade for the developed bio-binders may not vary significantly from the bitumen binders; however, the low temperature performance grade may vary significantly due to the high oxygen content in the bio-binders and subsequent aging compared to the bitumen binders

Improving Variability and Precision of Air-Void Analyzer (AVA) Test Results and Developing Rational Specification Limits

Since air-void analyzer (AVA) was introduced in the 1990s, various studies have been conducted in the United States to apply this technology. Many concerns are raised on (a) the variation of the AVA tests, (b) the relationship between AVA and other standard measurements, and (c) AVA specification limits. The application of AVA tests in concrete practice is therefore very challenging. The goals of the present research project are to reduce variability and improve precision of AVA test results and to develop rational specification limits for controlling concrete freezing and thawing (F-T) damage using the AVA test parameters. This project consists of three phases: (1) Phase 1—Literature search and analysis of existing AVA data (June 2007–August 2008), (2) Phase 2—AVA testing procedure and specification modification, (3) Phase 3—Field study of AVA and specification refinement. In the present research report, the major activities and findings of the Phase 1 study are presented, and the major tasks for the Phase 2 study are recommended. The major activities of the Phase 1 study included the following: performing a literature search, collecting and reviewing available AVA data, completing a statistical analysis on collected AVA data, and carrying out some AVA trial tests in lab. The results indicate that AVA is a time- and cost-effective tool for concrete quality control. However, robustness of the AVA equipment, test procedures, and resulting interoperations need further improvement for a proper implementation of the AVA technology in concrete practice

Global economic burden of unmet surgical need for appendicitis

Background: There is a substantial gap in provision of adequate surgical care in many low-and middle-income countries. This study aimed to identify the economic burden of unmet surgical need for the common condition of appendicitis. Methods: Data on the incidence of appendicitis from 170 countries and two different approaches were used to estimate numbers of patients who do not receive surgery: as a fixed proportion of the total unmet surgical need per country (approach 1); and based on country income status (approach 2). Indirect costs with current levels of access and local quality, and those if quality were at the standards of high-income countries, were estimated. A human capital approach was applied, focusing on the economic burden resulting from premature death and absenteeism. Results: Excess mortality was 4185 per 100 000 cases of appendicitis using approach 1 and 3448 per 100 000 using approach 2. The economic burden of continuing current levels of access and local quality was US $92 492 million using approach 1 and$73 141 million using approach 2. The economic burden of not providing surgical care to the standards of high-income countries was $95 004 million using approach 1 and$75 666 million using approach 2. The largest share of these costs resulted from premature death (97.7 per cent) and lack of access (97.0 per cent) in contrast to lack of quality. Conclusion: For a comparatively non-complex emergency condition such as appendicitis, increasing access to care should be prioritized. Although improving quality of care should not be neglected, increasing provision of care at current standards could reduce societal costs substantially

Pooled analysis of WHO Surgical Safety Checklist use and mortality after emergency laparotomy

Background The World Health Organization (WHO) Surgical Safety Checklist has fostered safe practice for 10 years, yet its place in emergency surgery has not been assessed on a global scale. The aim of this study was to evaluate reported checklist use in emergency settings and examine the relationship with perioperative mortality in patients who had emergency laparotomy. Methods In two multinational cohort studies, adults undergoing emergency laparotomy were compared with those having elective gastrointestinal surgery. Relationships between reported checklist use and mortality were determined using multivariable logistic regression and bootstrapped simulation. Results Of 12 296 patients included from 76 countries, 4843 underwent emergency laparotomy. After adjusting for patient and disease factors, checklist use before emergency laparotomy was more common in countries with a high Human Development Index (HDI) (2455 of 2741, 89.6 per cent) compared with that in countries with a middle (753 of 1242, 60.6 per cent; odds ratio (OR) 0.17, 95 per cent c.i. 0.14 to 0.21, P <0001) or low (363 of 860, 422 per cent; OR 008, 007 to 010, P <0.001) HDI. Checklist use was less common in elective surgery than for emergency laparotomy in high-HDI countries (risk difference -94 (95 per cent c.i. -11.9 to -6.9) per cent; P <0001), but the relationship was reversed in low-HDI countries (+121 (+7.0 to +173) per cent; P <0001). In multivariable models, checklist use was associated with a lower 30-day perioperative mortality (OR 0.60, 0.50 to 073; P <0.001). The greatest absolute benefit was seen for emergency surgery in low- and middle-HDI countries. Conclusion Checklist use in emergency laparotomy was associated with a significantly lower perioperative mortality rate. Checklist use in low-HDI countries was half that in high-HDI countries.Peer reviewe

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

Prevalence and risk factors of disabilities among Egyptian preschool children: a community-based population study

Abstract Background Child disability has significant implications on their well-being and healthcare systems. Aim: This survey aimed to assess the magnitude of seven types of disability among Egyptian children aged 1 < 6 years and their socio-demographic, epidemiological, and perinatal predictors. Methods A national population-based cross-sectional household survey targeting 21,316 children from eight governorates was conducted. The screening questionnaire was derived from the WHO ten-question survey tool validated for identifying seven disability categories. Results The percentage of children with at least one disability was 8.1% as follows: speech/communication (4.4%), Mobility/physical (2.5%), Seizures (2.2%), Comprehension (1.7%), Intellectual impairment (1.4%), Visual (0.3%) and Hearing (0.2%). Age was not found to affect the odds of disability except for visual disability (significantly increased with age (AOR = 1.4, 95% CI:1.1–1.7). Male sex also increased the odds of all disabilities except visual, hearing, and seizures. Convulsions after birth significantly increased the odds of disability as follows: hearing (AOR = 8.1, 95% CI: 2.2–30.5), intellectual impairment (AOR = 4.2, 95% CI: 2.5–6.9), and mobility/physical (AOR = 3.4, 95% CI: 2.3–5.0). Preterm delivery and being kept in an incubator for more than two days after birth increased the odds for visual disability (AOR = 3.7, 95% CI: 1.1–12.1 & AOR = 3.7, 95% CI: 1.7–7.9 respectively). Cyanosis increased the odds of seizures (AOR = 4.7, 95% CI: 2.2–10.3). Low birth weight also increased the odds for all disability domains except for visual and hearing. Maternal health problems during pregnancy increased the odds for all types of disability except hearing and seizures. Higher paternal education decreased the odds for all disabilities by at least 30% except for vision and hearing. Conclusion The study found a high prevalence of disability among Egyptian children aged 1–6 years. It identified a number of modifiable risk factors for disability. The practice of early screening for disability is encouraged to provide early interventions when needed

Additional file 2 of Prevalence and risk factors of disabilities among Egyptian preschool children: a community-based population study

Additional file 2: S Table 2. All data disability less than 6