On Dynamic Modulus of Asphalt Concrete for Moisture Damage

Dynamic modulus (E*) test has gained substantial acceptance in recent years for evaluating Hot Mix Asphalt (HMA) rutting and fatigue cracking performances. Indeed, the recently developed Mechanistic Empirical Pavement Design Guide (MEPDG) uses E* data for stress and strain calculation, and E*-based models for prediction fatigue and rutting performances of a HMA pavement. Unfortunately, neither HMA mix design method nor the MEPDG uses E* value to evaluate moisture damage characteristics of HMA pavements. In fact, moisture damage is a very complex problem, and there exists no models for inclusion in the MEPDG for predicting moisture damage performance of HMA pavements. Rather, moisture damage performance of HMA is evaluated during the mix design state using the AASHTO T 283 test. According to AASHTO T 283 method, indirect tensile strength ratio of wet to dry samples is used as an indicator of moisture damage performance of a HMA mix. The AASHTO T 283 is a simple method, but it is not very reliable. In some cases, it gives false negative and positive values about the moisture damage characteristic of an HMA sample. To this end, this study attempts to study moisture damage in Asphalt Concrete (AC) sample by determining the loss in dynamic modulus (E*) value based on continuum damage mechanics. The loss in E* is evaluated by calculating the ratio of wet E* to dry E* (DMR). In this study, E* testing is performed on five different asphalt mixtures. Three of the asphalt mixtures are plant produced Superpave mixes, and the other two are laboratory prepared HMA mix. The plant produced mixes include SP-II mix with asphalt binders Performance Grade (PG) PG 64-22, SP-III mix with PG 70-22, and SP-IV mix with PG 70-22. The laboratory mixes are SP-III mix with PG 64-22, and SP-II with binder PG 70-22. The E* test is conducted at five temperatures (-10, 4, 21, 37, 54 °C) and six frequencies (25, 10, 5, 1, 0.5, 0.1 Hz). The resulting E* data are used to generate time-temperature mastercurves. Also, the laboratory E* data is fitted to several models such as the viscosity (\u03b7) -based Witczak model, the dynamic shear modulus (G*) -based Witczak models, and the Hirsch model. However, all models are found to underpredict the laboratory E* values. Therefore, the \u03b7-based Witczak model is modified to improve E* prediction accuracy in this study and E* ratios are used for evaluating moisture damage in AC. As mentioned above, the most common test method for evaluating moisture damage susceptibility of HMA mix is the AASHTO T 283. According to the AASHTO T 283, a dry asphalt concrete sample is vacuum saturated and then subjected to one cycle of freezing and thawing. However, one cycle of freeze-thaw does not simulate moisture condition resulting from repeated pore water pressure buildup and scouring cycles that occur when vehicle tires pass over a saturated pavement. Recently, Moisture Induced Sensitivity Tester (MIST) equipment can apply repeated pore pressure cycles inside an AC sample in the laboratory. Therefore, MIST device is employed in this study to cause damage in AC samples. Moisture damage resulting from MIST conditioning is then evaluated using the Dynamic Modulus Ratio (DMR) of wet to dry samples. MIST conditioning is performed at three different pressures (40, 55, 70 psi), three temperatures (40, 50, 60 \xbaC) and three different numbers of cycles (3500, 7000 and 10,500). MIST conditioning is found to decrease the E* value of asphalt concrete indicating the presence of moisture damage. The average DMR is observed to decrease from 1.0 to 0.85, 0.46 and 0.56 for MIST conditioning at 3500, 7000 and 10500 cycles, respectively. When the MIST conditioning temperature is increased to 40, 50 and 60 \xbaC, the average DMR decreases from 1.0 to 0.90, 0.82 and 0.76, respectively. The DMR at 276, 376 and 483 kPa MIST conditioning pressures are determined to be 1.0, 0.91 and 0.72, respectively. Therefore, moisture damage increases with an increase in number of cycles, temperatures and pressures. However, it is shown that temperature affects moisture damage less significantly than the number of cycles and pressures in a MIST device. Therefore, number of traffic and magnitude of traffic loading should be considered carefully to design moisture damage free pavements.\u2

Substantive international law limitations and problems

The proliferation of small arms and light weapons (SALW) [about 700 million in circulation] has been causing deplorable security and other concerns of international law. SALW are the primary tools of violations/abuses of humanitarian principles by states, rebels, terrorists and criminals many consider them as the real weapons of mass destruction [พMD] of our time [about half a million deaths annually]. The unrestricted international transfers of SALW by states [99 states and 1000 companies involved in manufacturing and supply] is one of the major contributory and/or aggravating factor to the crises they are the main source of the illicit trafficking in small arms, and therefore deserves prime attention. This thesis has dealt with questions of definition, manufacturing, trade/transfers, and some issues of state responsibility. Whilst a wide approach has been adopted to define SALW, the focus of the research has been on conventional small arms, in particular military-style weapons. There seems no substantive restriction upon small arms manufacture, although there are evolving norms to that effect. Issues of definition and manufacturing have been examined as a background to the main issue. The core legal problem tackled in the thesis is whether or not the law of arms control and other relevant norms of international law provide substantive restrictions upon the transfer of small arms by states, as a response to the crisis, with emphasise on supply-side of the issue. Some studies and publicists submitted that there are no rules of international law applicable to these transactions, save Security Council arms embargoes. The thesis will challenge this assertion from the perspective of the application of the norms of international peace and security, non-intervention, humanitarian and human rights laws, and/or evolved relevant customary rules of arms control relating to these norms. It will be argued that the international order has acquired applicable arms control and other existing obligations and restrictions, upon such transactions. Whilst the application of the aforementioned norms of international law to the problem has been fairly examined, the practices of the international community at all levels, including the position of prominent NGOs and publicists on the subject, have been particularly considered in the light of sources of international law and analogous legal regimes. The details of the legal standards are subject to the progressive development of international law; however, their violations may lead to the weapon supplier, recipient or other states’ primary responsibility. Finally, findings and recommendations of the thesis have highlighted the achievements and challenges of the international community and the legal measures that must be taken to arrest the illegal small arms transfer and their atrocious consequences

P-TECH SCHOOL IN TRANSPORTATION AND SUPPLY CHAIN MANAGEMENT PROGRAM: A CASE OF BALTIMORE CITY COMMUNITY COLLEGE

Four years high school students took the opportunity of early college access and dual enrolment program by taking college courses while they are at a high school. In recent years several states including Maryland supported the development of a new model of early college access program for high school students called Pathways in Technology Early College High Schools (P-TECH) 9-14 schools. With the P-TECH 9-14 school model in six years or less students graduate with a high school diploma and a no cost two-year associate degree in STEM fields. This paper discusses the recently developed new P-TECH transportation program at Baltimore City Community College. The program focuses on the supply chain management career pathway to meet the present and future needs of the region. P-TECH schools work with industry partners and a local community college to ensure an up-to-date curriculum that is academically rigorous and economically relevant. P-TECH programs also include mentoring, workplace visits and instruction on the skills needed for the industry and paid internships and job consideration with the partnering companies

Assessment of Taxpayers voluntary compliance with Taxation: A case of Mekelle City, Tigray, Ethiopia

Improved tax compliance boosts the revenues available for supporting public services without increasing the current tax burden on compliant tax payers. There appears to be a trend in tax compliance policies with initiatives by a number of tax authorities to move towards a more taxpayer focused approach. A number of tax authorities have been moving towards a more sophisticated approach to tax compliance. Traditionally there seems to have been an assumption that tax compliance can be ensured with the help of legal enforcement and penalties. These days this is ceasing to be the case, as the taxpayers are demanding more assistance and fair treatment from the tax authorities. Even there seems to have been a shift in attitudes towards treating the taxpayer less as a passive donor who simply has to be billed for taxes due and more as a customer sometimes requiring particular forms of assistance and support. The voluntary compliance behavior of the taxpayers is determined by various factors and identifying these factors and treating them accordingly should be the central premises of any tax system in order to maintain voluntary compliance at satisfactory levels. This study was meant to assess taxpayers’ voluntary compliance with taxation in Mekelle city. Based on this fact, both primary and secondary data are used. Descriptive statistical tools and Reliability test, Factor analysis, correlation and multiple regressions are used in analyzing the data collected. According to the study, factors such as equity or fairness, organizational strength of tax authority, awareness level of tax payers, social factors, cultural factors and tax payers’ attitude towards the government were found to be the determinant factors affecting taxpayers’ voluntary compliance. Finally, based on the findings possible recommendations were given. These include, maintaining tax fairness and equity, building capacity of the tax authority, conducting extensive awareness creation programs, and providing social services to the general public

Correction: Elevated triglycerides and reduced high-density lipoprotein cholesterol are independently associated with the onset of advanced chronic kidney disease: a cohort study of 911,360 individuals from the United Kingdom (BMC Nephrology, (2022), 23, 1, (312), 10.1186/s12882-022-02932-2)

Following publication of the original article [1], the authors informed us that the confidence interval is missing in Table 2, Column 5, row Q2. It should be 1.01 [0.95-1.09]. The original article has been corrected

Inter-sectoral economic linkages in the mining industries of Botswana and Tanzania:Analysis using partial hypothetical extraction method

Fiscal and local content policies aimed at promoting linkages between mining and other economic sectors have been informed by theories built on historical observations dating back to the 1950s. This paper contends that there is a need to rethink theories about mining-based economic linkages and the prospects for structural change based on an improved understanding of existing and potential inter-sectoral linkages. Using the input–output tables for Tanzania and Botswana, we apply the Partial Hypothetical Extraction Method within the Leontief and Gosh input–output frameworks to examine the linkages between the mining and quarrying sector and other economic sectors within these two economies. We find that, for Botswana, possible linkage pathways lie in scaling-up coal, soda ash and salt mining and investing in glass, polymer, and chemicals manufacturing. For Tanzania, opportunities for linkage pathways lie with the mining and manufacturing of non-metallic and construction materials as well as metallic minerals and natural gas. For both countries, the prospects for transforming their economies away from a heavy reliance on mineral extraction hinges on leveraging extractives for infrastructure, innovative technology, and technical skills, as well as capturing business opportunities, knowledge, and financial returns to invest in more diversified economic activities.</p

Evaluation of renal end points in nephrology trials

Chronische nierschade is een volksgezondheidsprobleem en wordt in verband gebracht met een hoog risico op dialyse, niertransplantatie en cardiovasculaire ziekten. Tot op heden zijn weinig interventies bewezen effectief gebleken in het vertragen van de progressie van de daling in de nierfunctie. Nieuwe therapeutische strategieën zijn dus gewenst om de hoge medische behoefte van chronische nierschade aan te pakken. Klinische uitkomststudies zijn nodig om de werkzaamheid en veiligheid van een geneesmiddel te bepalen. De huidige gebruikte eindpunten voor chronische nierschade zijn dialyse en niertranplantatie. Aangezien het lang duurt voordat de nierziekte zover gevorderd is dat men besluit om over te gaan op dialyse of niertransplantatie zijn er grote langdurige en complexe klinische studies nodig om de werkzaamheid van nieuwe interventies vast te stellen. In dit proefschrift zijn nieuwe definities voor eindpunten van klinische studies voor chronische nierschade onderzocht met als doel om een eindpunt te vinden die eerder in het beloop van de nierziekte plaats vindt zodat in de toekomst kleinere en minder complexe studies kunnen worden uitgevoerd. De bevindingen die in dit proefschrift zijn beschreven wijzen erop dat het optimale eindpunt in klinische studies naar de progressie van chronische nierschade, een samengesteld eindpunt moet zijn bestaande uit een daling van de nierfunctie en een klinisch zinvol eindpunt zoals dialyse of niertransplantatie. Met behulp van studies in dit proefschrift is een nieuw eindpunt gedefinieerd gebaseerd op daling van de nierfunctie, namelijk een 30% en 40% afname in de glomerulaire filtratie snelheid (eGFR). Dit eindpunt wordt momenteel gebruikt in nieuwe klinische studies naar de progressie van chronische nierschade

Socioeconomic disadvantage and the risk of advanced chronic kidney disease: results from a cohort study with 1.4 million participants

Background Several studies have investigated the effect of socioeconomic deprivation on cardiovascular disease (CVD) and diabetes; less is known about its effect on chronic kidney disease (CKD). We aimed to measure the association between deprivation, CKD Stages 4–5 and end-stage renal disease (ESRD) in a general population sample. Methods This observational study examined 1 405 016 participants from the English Clinical Practice Research Datalink (2000–14), linked to hospital discharge data and death certification. Deprivation was assessed according to the participant’s postcode. Cox models were used to estimate hazard ratios (HRs) for CKD Stages 4–5 and ESRD, adjusting for age and sex, and additionally for smoking status, body mass index, diabetes, systolic blood pressure, prior CVD and estimated glomerular filtration rate (eGFR) at baseline. Results During 7.5 years of median follow-up, 11 490 individuals developed CKD Stages 4–5 and 1068 initiated ESRD. After adjustment for age and sex, the HRs and confidence interval (CI) comparing those in the 20% most deprived of the population to the 20% least deprived were 1.76 (95% CI 1.68–1.84) and 1.82 (95% CI 1.56–2.12) for CKD Stages 4–5 and ESRD, respectively. Further adjustment for known risk factors and eGFR substantially attenuated these HRs. Adding our results to all known cohort studies produced a pooled relative risk of 1.61 (95% CI 1.42–1.83) for ESRD, for comparisons between highest to lowest categories of deprivation. Conclusion Socioeconomic deprivation is independently associated with an increased hazard of CKD Stages 4–5 and ESRD, but in large part may be mediated by known risk factors