Analysis of Short-Term Prestress Losses in Post-tensioned Structures Using Smart Strands

The proper estimation of prestressing force (PF) distribution is critical to ensure the safety and serviceability of prestressed concrete (PSC) structures. Although the PF distribution can be theoretically calculated based on certain predictive equations, the resulting accuracy of the theoretical PF needs to be further validated by comparison with reliable test data. Therefore, a Smart Strand with fiber optic sensors embedded in a core wire was developed and applied to a full-scale specimen and two long-span PSC girder bridges in this study. The variation in PF distribution during tensioning and anchoring was measured using the Smart Strand and was analyzed by comparison with the theoretical distribution calculated using the predictive equations for short-term prestress losses. In particular, the provisions for anchorage seating loss and elastic shortening loss were reviewed and possible improvements were proposed. A new method to estimate the amount of anchorage slip based on real PF distributions revealed that the general assumption of 3–6-mm slip falls within a reasonable range. Finally, the sensitivity of the PF distribution to a few of the variables included in the equation of the elastic shortening loss was examined. The study results confirmed that the developed Smart Strand can be used to improve the design parameters or equations in PSC structures by overcoming the drawbacks of conventional sensing technologies.

The frequency of periodontitis in end-stage renal disease on hemodialysis in a sample of Egyptian population: multi-center clinical cross-sectional study

Background There is a general assumption that periodontal disease is highly prevalent among patients with chronic renal failure undergoing hemodialysis. The aim of the study to estimate the frequency of periodontitis in patients on hemodialysis among a sample of the Egyptian population, as well as the correlation between different clinical parameters of periodontal status with serum creatinine and blood urea. This may rule out the bidirectional relationship between periodontitis and renal failure in patients on hemodialysis. Methods The study was conducted on 263 hemodialysis patients (165 males and 98 females) at three dialysis centers in Benha Governorate, Egypt (Benha Hospital, Tukh hospital, Qalyub hospital). Periodontal parameters including plaque index (PI), gingival index (GI), clinical attachment level (CAL), and probing pocket depth (PPD) had been recorded in these patients. Serum urea and creatinine levels had been measured, the data had been collected and undergone statistical analysis. Results Frequency of periodontitis was 85.6% with stage III is the most prevalent stage. There was a significant positive strong correlation between age and periodontitis stage (rs = 0.707, p < 0.001). There was a positive correlation between clinical parameters and serum creatinine level. Conclusion In the present study, a high frequency of periodontitis had been found among ESRD patients on hemodialysis in the severe form (stage III) periodontitis. There was a significant direct correlation between the severity of periodontitis and CAL with a duration of hemodialysis. There was a weak insignificant association between periodontal indices (PD, BOP, and plaque score) and duration of hemodialysis.

The Negative Effect of Job Insecurity in the Virtuous Cycle Between Trust in the Organization, Subjective Well-Being, and Task Performance in the Current Volatility, Uncertainty, Complexity, and Ambiguity Context

Over the past decade, job insecurity referring to the employees’ perceived threat to the continuity and stability of employment as it is currently experienced has become a hot topic. A general assumption, supported by the findings, is that job insecurity causes far-reaching negative consequences for the employee health and well-being, attitudes toward organization and the job, and behaviors at work. However, the focus on behavioral outcomes, especially on employee performance at work, is still scant. Moreover, the literature remains fragmented concerning the impact of job insecurity on employee trust in the organization and how the trust influences employee subjective well-being (SWB), which in turn affects employee performance. Consequently, the link between job insecurity and SWB needs more investigation. Trying to narrow the gap, the paper aims at revealing the linkage between job insecurity, trust in the organization, SWB, and task performance. Quantitative data were collected in Lithuania. As predicted, the results revealed that job insecurity had a negative impact on trust in the organization and employee SWB. In case of linkage between job insecurity and task performance, the hypothesis was rejected. In general, these findings affirmed that job insecurity was a hindrance stressor, which needed to be considered when managing human resources in the current volatility, uncertainty, complexity, and ambiguity context.

Discussion and Analysis of Dumbbell Defect-Ground-Structure (DB-DGS) Resonators for Sensing Applications from a Circuit Theory Perspective

Microstrip transmission lines loaded with dumbbell defect-ground-structure (DB-DGS) resonators transversally oriented have been exhaustively used in microwave circuits and sensors. Typically, these structures have been modelled by means of a parallel LC resonant tank series connected to the host line. However, the inductance and capacitance of such model do not have a physical meaning, since this model is inferred by transformation of a more realistic model, where the DB-DGS resonator, described by means of a resonant tank with inductance and capacitance related to the geometry of the DB-DGS, is magnetically coupled to the host line. From parameter extraction, the circuit parameters of both models are obtained by considering the DB-DGS covered with semi-infinite materials with different dielectric constant. The extracted parameters are coherent and reveal that the general assumption of considering the simple LC resonant tank series-connected to the line to describe the DB-DGS-loaded line is reasonable with some caution. The implications on the sensitivity, when the structure is devoted to operating as a permittivity sensor, are discussed.

A modelling study of temporal and spatial <i>p</i>CO₂ variability on the biologically active and temperature-dominated Scotian Shelf

Continental shelves are thought to be affected disproportionately by climate change and are a large contributor to global air–sea carbon dioxide (CO2) fluxes. It is often reported that low-latitude shelves tend to act as net sources of CO2, whereas mid- and high-latitude shelves act as net sinks. Here, we combine a high-resolution regional model with surface water time series and repeat transect observations from the Scotian Shelf, a mid-latitude region in the northwest North Atlantic, to determine what processes are driving the temporal and spatial variability of partial pressure of CO2 (pCO2) on a seasonal scale. In contrast to the global trend, the Scotian Shelf acts as a net source. Surface pCO2 undergoes a strong seasonal cycle with an amplitude of ∼ 200–250 µatm. These changes are associated with both a strong biological drawdown of dissolved inorganic carbon (DIC) in spring (corresponding to a decrease in pCO2 of 100–200 µatm) and pronounced effects of temperature, which ranges from 0 ∘C in the winter to near 20 ∘C in the summer, resulting in an increase in pCO2 of ∼ 200–250 µatm. Throughout the summer, events with low surface water pCO2 occur associated with coastal upwelling. This effect of upwelling on pCO2 is also in contrast to the general assumption that upwelling increases surface pCO2 by delivering DIC-enriched water to the surface. Aside from these localized events, pCO2 is relatively uniform across the shelf. Our model agrees with regional observations, reproduces seasonal patterns of pCO2, and simulates annual outgassing of CO2 from the ocean of +1.7±0.2 mol C m−2 yr−1 for the Scotian Shelf, net uptake of CO2 by the ocean of -0.5±0.2 mol C m−2 yr−1 for the Gulf of Maine, and uptake by the ocean of -1.3±0.3 mol C m−2 yr−1 for the Grand Banks.

Digital Tools Acceptance in Open Distance Learning (ODL) among Computer Science Students during COVID-19 Pandemic: A Comparative Study

The present new norm driven by the COVID-19 pandemic has taught us to remain at home and carry our everyday activities. This pandemic has seriously made a radical shift to the Malaysian education sector as well. Educators instantly begin to adopt Open and Distance Learning (ODL). However, issues arise in courses that need a conventional setting. In ODL, students and lecturers rely on digital tools, social media, pre-recorded video, and video conference to assist the learning process. Nonetheless, there are some concerns about how successful digital tools are among students in an online learning environment, particularly among computer science students. Thus, a study is being conducted to compare the acceptance of digital tools among computer science (CS) and non-computer science (NoNCS) students by adapting the Technology Acceptance Model (TAM). A quantitative research method of convenient sampling was undertaken. Questionnaires were distributed through an online survey among UiTM Terengganu students at three campuses in Dungun, Bukit Besi and Kuala Terengganu. A sample of 367 students who responded from different diploma and degree programs was collected. Findings of the study revealed that all relationships in TAM are significant for both CS and NoNCS students, where both acquire positive perceived usefulness, attitude, and use intention. Thus, the acceptance of digital tools in ODL are justified. However, it appears that NoNCS students had a more positive attitude than CS students, contradicting the study's initial general assumption. More study is needed to discover why NoNCS students have a better attitude than CS students in the acceptance of digital tools during ODL. Keywords: Computer Science, COVID-19, Digital Tools, ODL, TAM

The Huns (‘Hūṇas’) in India: A Review

Limited attention seems to have been paid in Indian historical work to the Hūṇas (Huns) except for the general assumption that they played a very destructive role in Indian history. There is need for a fresh appraisal of the Hūṇa polity in the light of the Schūyen copper scroll, and further work on the numismatic evidence, while the details of their conflict with the Guptas need to be properly worked out. Finally, the objective behind their deep intrusion into central India (especially Malwa) has to be located in a broader context.

Environmental effect of biodiesel mandatory policy

One major biofuel in Indonesia is biodiesel with palm oil constituting the predominant raw material. Over recent years, biodiesel has become the most rapidly developing and influential aspect for economic. Biodiesel mandatory policies aim to reduce import of diesel from fossil fuels, buffer for CPO price, reduce emissions and balancing supply demand of palm oil. The biodiesel policy is supported by the CPO fund mechanism managed by BPDPKS to overcome the price gap of diesel and biodiesel which is affected by volatile price of CPO and fossil fuels. About 8 million ton (5%) CPO production in Indonesia is allocated for biodiesel production to supply domestic and overseas markets. In the long term, palm oil-based biodiesel will become the focus of renewable energy development policy in Indonesia. National energy policy direction ensures an optimum energy mix, with renewables targeted to contribute up 31% of the energy mix by 2050. These are optimistic targets that hope to be achieved over various constraints, such as issues of land for feedstock, gap price between biodiesel prices and diesel fuels, dependence on imported technologies and equipment, and low market demand for biodiesel, particularly in sectors with no government intervention. There is a general assumption that biodiesel or bioenergy already fall in line with sustainability principles as they are sourced from the agriculture sector. The study aims to examine the impact of biodiesel development to economic and environment, also to review several challenges facing by biodiesel development in Indonesia.

Multilateral Principles in a Bilateral World

Multilateralism in international investment law is a multifaceted concept with a complex and eventful history. Multilateralism is a paradigm for international investment relations and is also present in the caselaw of investment arbitral tribunals, regardless of whether they consider bilateral or multilateral investment treaties. Indeed, in most cases, they interpret treaty provisions as part of a multilateral system. Further, multilateralism is present every time States act in concert with other States or consider other States’ investors’ legitimate interests. It also emerges that, in some instances, multilateralism has become mandatory. For example, this is the case concerning sustainable development or climate change. In these areas, international law requires multilateralism. States are under an obligation to co-operate for purposes of achieving or promoting multilateral solutions. However, concerning the international investment law context, such a concept is not present. The general assumption is that States’ participation in multilateral practises is left to their discretion: it is voluntary or consensual. In this article, we question that assumption. In this article, we offer a brief review of multilateral experiences in international investment law in the 20th century and provide an analysis of multilateralism in a historical context. Then we turn our attention to the current state of affairs to appreciate it in light of the past. Further, we discuss the future, and in particular, mandatory multilateralism in international law with respect to sustainable development. Here we identify the principles, which might justify mandatory multilateral approaches. Finally, we consider whether the principles justifying mandatory multilateralism in international law are applicable in the context of international investment law as well. We attempt to answer this question in the affirmative and point out further areas of research.

Is the Phenylalanine-Restricted Diet a Risk Factor for Overweight or Obesity in Patients with Phenylketonuria (PKU)? A Systematic Review and Meta-Analysis

Although there is a general assumption that a phenylalanine (Phe)-restricted diet promotes overweight in patients with phenylketonuria (PKU), it is unclear if this presumption is supported by scientific evidence. This systematic review aimed to determine if patients with PKU are at a higher risk of overweight compared to healthy individuals. A literature search was carried out on PubMed, Cochrane Library, and Embase databases. Risk of bias of individual studies was assessed using the Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies, and the quality of the evidence for each outcome was assessed using the NutriGrade scoring system. From 829 articles identified, 15 were included in the systematic review and 12 in the meta-analysis. Body mass index (BMI) was similar between patients with PKU and healthy controls, providing no evidence to support the idea that a Phe-restricted diet is a risk factor for the development of overweight. However, a subgroup of patients with classical PKU had a significantly higher BMI than healthy controls. Given the increasing prevalence of overweight in the general population, patients with PKU require lifelong follow-up, receiving personalised nutritional counselling, with methodical nutritional status monitoring from a multidisciplinary team in inherited metabolic disorders.