Scattering of Fexural Gravity Waves by a Two-Dimensional Thin Plate

An approximate analysis based on standard perturbation technique together with an application of Green’s integral theorem is used in this paper to study the problem of scattering of water waves by a two dimensional thin plate submerged in deep ocean with ice cover. The reflection and transmission coefficients upto first order are obtained in terms of the shape function describing the plate and are studied graphically for different shapes of the plate

Perceptions and attitudes of Rohingya community stakeholders to pregnancy termination services: a qualitative study in camps of Cox’s Bazar, Bangladesh

Background: Rohingya women suffer from inaccessibility to sexual and reproductive health services in Myanmar. After the forcible displacement of the Rohingya from Myanmar to Bangladesh in 2017, pregnancy termination services have been increasingly important and desired, while knowledge gaps and obstacles to access services still exist. The role of community stakeholders is critical as gatekeepers and decision-makers to improve and strengthen pregnancy termination services for women in camps. However, there is paucity of evidence on their perspectives about pregnancy termination. This qualitative study aims to understand the perception and attitudes of Rohingya community stakeholders to pregnancy termination in the camps of Cox’s Bazar. Methods: We used purposive sampling to select 48 participants from the community stakeholders, 12 from each group: majhis (Rohingya leaders), imams (religious leaders), school teachers, and married men. We conducted in-depth interviews of all the participants between May-June 2022 and October-November 2022. Data were coded on Atlas.ti and analysed using a thematic content analysis approach. Results: Multiple socio-cultural and religious factors, gendered norms and stigma associated with pregnancy termination acted as barriers to women seeking services for it. From a religious stance, there was greater acceptance of pregnancy termination in the earlier period than in the later period of pregnancy. We observed that pregnancy termination among community stakeholders in earlier stages of pregnancy than later. However, circumstances, such as a woman’s marital status, whether she sought her husband’s permission or her ability of childcare capacity, were often framed by community stakeholders as ‘acceptable’ for pregnancy termination. Health concerns and social and contextual factors can influence community stakeholders supporting pregnancy termination. Conclusions: The community stakeholders perspectives on barriers and enablers of pregnancy termination were variable with the context. These perspectives may support or impede women’s ability to choice to seek pregnancy termination services. To improve women’s choice to pregnancy termination, it is critical to consider roles of community stakeholders in creating their supporting attitudes to women’s choice and access, and to designing targeted culturally appropriate interventions with communities support and engagement

Effect of charge and spin multiplicity on hyperpolarizabilities of donor-acceptor substituted polyenes

Theoretical studies of the ground state structure and nonlinear optical (NLO) properties of a number of donor-acceptor substituted singlet and triplet (neutral) and doublet (mono-positive and mono-negative) polyenes have been carried out. The variation of NLO property of the investigated molecules has been explained by using previously derived relationships between the different order polarizabilities and ground state dipole moment obtained in the framework of the standard sum-over-state expressions of Orr-Ward-Bishop and the generalized Thomas-Kuhn sum rule. The effect of charge and spin multiplicity on the molecular hyperpolarizabilities have been discussed in terms of relative changes of polarizability and ground state dipole moment. Among the investigated polyenes, the isotropic polarizability and the second-hyperpolarizability are predicted to be larger for the doublet anions in which the NH2 group is pyramidal. The position of nitrogen atom in the p-conjugative path strongly modulates the magnitudes of both the first- and second-hyperpolarizabilities of the investigated polyenes

Bridge Decks: Mitigation of Cracking and Increased Durability—Materials Solution (Phase III)

Type K cement offers a lower slump than conventional concrete, even at a higher water-to-cement ratio. Therefore, a suitable chemical admixture should be added to the Type K concrete mix design at a feasible dosage to achieve and retain target slump. In this project, a compatibility study was performed for Type K concrete with commercially available water-reducing and air-entraining admixtures. Slump and air content losses were measured over a period of 60 minutes after mixing and a particular mid-range water-reducing admixture was found to retain slump effectively. Furthermore, no significant difference in admixture interaction between conventional and Type K concrete was observed. Another concern regarding the use of Type K concrete is that its higher water-to-cement ratio can potentially lead to higher permeability and durability issues. This study also explored the effectiveness of presoaked lightweight aggregates in providing extra water for Type K hydration without increasing the water-to-cement ratio. Permeability of concrete was measured to validate that the use of presoaked lightweight aggregates can lower water adsorption in Type K concrete, enhancing its durability. Extensive data analysis was performed to link the small-scale material test results with a structural test performed at Saint Louis University. A consistent relation was established in most cases, validating the effectiveness of both testing methods in understanding the performance of proposed shrinkage-mitigation strategies. Stress analysis was performed to rank the mitigation strategies. Type K incorporation is reported to be the most effective method for shrinkage-related crack mitigation among the mixes tested in this study. The second-best choice is the use of Type K in combination with either presoaked lightweight aggregates or shrinkage-reducing admixtures. All mitigation strategies tested in this work were proved to be significantly better than using no mitigation strategy.IDOT-ICT-178-1Ope