Effect of Sediment Supply on Morphodynamics of Free Alternate Bars: Insights from Hydrograph Boundary Layer

Sediment supply plays an essential role in river morphology. However, the specific impact of sediment supply on river morphology is not apparent. According to the hydrograph boundary layer (HBL) concept, upstream riverbed changes caused by the imbalance between sediment supply and the capacity can propagate only a limited length and have a negligible effect on the riverbed beyond such a short length. We performed a two-dimensional morphodynamic calculation to test the concept of HBL, which was proposed under a one-dimensional simulation, meaning that the concept of HBL is still valid for plane changes in river morphology. We employed an unsteady flow with equilibrium or constant sediment supply in a straight, modeled gravel-bedded channel with an unerodible bank to simulate alternate bar morphodynamics. The results show that regardless of the sediment supply condition, the alternate bar features formed downstream of the HBL are considerably similar. This suggests that sediment disturbance at the upstream end has a negligible effect on the mobile-bed dynamic processes, including alternate bar formation and development downstream of the HBL.

Sensitivity analysis of centrifugal compressors aerodynamic losses using 1D-mean streamline prediction technique

One-dimensional modeling and prediction of the centrifugal compressor performance are challenging as they require conservation equations and empirical and semi-empirical correlations. Therefore, there is a need to perform a consolidated study of the compressor aerodynamic loss models to conclude the importance of each loss to the compressor performance modeling. Accordingly, the purpose of this paper is to examine the effect of each aerodynamic loss on the compressor performance and explore more about which loss could have a negligible effect on the compressor performance. A MATLAB code was developed to predict the performance of five different small turbocharger centrifugal compressors at different geometric and operating conditions. The developed code was validated using the available experimental data of the investigated compressors. A sensitivity analysis methodology was performed using the validated code to check the effect of ten aerodynamic losses for the impeller and volute sections on the compressor performance. This paper concludes that impeller disk friction, blade loading, and clearance losses have a negligible effect on the small turbocharger vanless diffuser compressor performance.

Selfish learning is more important than fair-minded conditional cooperation in public-goods games

Why does human cooperation often unravel in economic experiments despite a promising start? Previous studies have interpreted the decline as the reaction of disappointed cooperators retaliating in response to lesser cooperators (conditional cooperation). This interpretation has been considered evidence of a uniquely human form of cooperation, motivated by altruistic concerns for fairness and requiring special evolutionary explanations. However, experiments have typically shown individuals information about both their personal payoff and information about the decisions of their groupmates (social information). Showing both confounds explanations based on conditional cooperation with explanations based on individuals learning how to better play the game. Here we experimentally decouple these two forms of information, and thus these two learning processes, in public goods games involving 616 Swiss university participants. We find that payoff information leads to a greater decline, supporting a payoff-based learning hypothesis. In contrast, social information has small or negligible effect, contradicting the conditional cooperation hypothesis. We also find widespread evidence of both confusion and selfish motives, suggesting that human cooperation is maybe not so unique after all.

Density functional theory study of adsorption and diffusion of potassium atoms on zigzag graphene nanoribbons with different terminal groups

Despite the extensive use of graphene-based materials in K-ion batteries, the effects of various edge morphologies of graphene on K atom adsorption and diffusion are unclear. In this study, the effects of K atom adsorption and diffusion on zigzag graphene nanoribbons (ZGNRs) with hydrogen (−H), ketone (=O), hydroxyl (−OH), and carboxyl (−COOH) terminal groups were investigated by density functional theory calculations. ZGNRs terminating with −H, =O and −COOH promote K atom adsorption, whereas those terminating with −OH suppress it. The −H, =O, −OH and −COOH terminations have a negligible effect on K atom diffusion in the inner region of ZGNRs. In the edge region, the diffusion barriers are nearly unchanged for −H and −OH terminations; however, they are increased for =O and −COOH terminations in the edge region compared to those in the inner region. All the terminal groups hinder K atom diffusion from the edge region toward the inner region. Our results suggest that −H termination enhances K atom adsorption and has a negligible effect on the diffusion barrier of K atom in the edge region. Therefore, the ZGNR with −H termination could be a promising candidate for K-ion batteries.

Ochratoxins’ Effects on the Functional Properties and Nutritional Compositions of Grains

This study assessed the effects of total ochratoxins on the nutritional composition and functional properties of grain flours. The grains cowpea, sorghum, maize, groundnut, rice, millet, and acha were milled. The proximate composition, functional properties, as well as Total Ochratoxin levels, were determined. The effects of the Ochratoxins on the nutritional and functional properties of the grains were evaluated. Ochratoxin levels in grain flours ranged from 0.09 to 54.41 μg/kg and not seen in some rice samples. Most Total Ochratoxin levels found in the grains were beyond the WHO/EU/FAO permissible limit, 5.00 µg/kg. Groundnut and Cowpea have a significant high content of protein and fiber. Groundnut had the highest average fat content, 41.84 %. The ash content of the grains ranged from 0.73 to 3.61%. The presence of ochratoxins had a significant impact on the grain's carbohydrates, proteins, and fat. Their presence had moderate effects on crude fiber, ash, and functional properties and negligible effect on grain moisture.

Effect of Profitability, Leverage, and Liquidity on Dividend Policy: Evidence from Manufacturing Companies in Indonesia

Profitability (ROA) and leverage (DER) have a favorable and material impact on the dividend policies of food and beverage manufacturing companies listed on the IDX. That is, if profitability and leverage continue to improve, so will the dividend policy. In comparison to liquidity (current ratio), which has a positive but negligible effect on the dividend policy of food and beverage manufacturing companies that are listed on the IDX. It may be concluded that while liquidity owned by the company can help enhance dividends, it cannot have a major impact on dividend policy reform. Increased dividend policy will entice investors. Thus, dividend policy can be improved by this research by optimizing asset utilization (ROA) and lowering the danger of debt relief (DER).

Alliances, signals of support, and military effort

Do alliances allow states to share defense burdens and reduce military spending? Despite expectations that alliances should lead to decreased military spending, the empirical record offers mixed findings. We argue that not all alliances are reliable; thus, only allies that receive signals of reassurance will rely on the external security of allies and subsequently reduce their military spending. Compared to states that do not receive additional signals, these reassured allies will have greater confidence that an ally will come to their aid. As a result, third-party aggressors are deterred and the demand for military spending will decrease. We test this argument with an analysis of US signals of support, alliance commitments, and military spending. We find that American alliances without additional signals of support have a negligible effect on military spending. Yet, we observe that alliances are negatively associated with military spending when signals of support are present. Additional tests indicate that alliance commitments, coupled with strong US signals, are also associated with lower military spending in the rivals of US allies. Our results potentially help explain the mixed evidence in the arms-versus-allies and burden-sharing literatures and further demonstrate that extra-alliance signals play an important role in the practice of International Relations.

Determinants of climbing energetic costs in humans

Previous studies in primates and other animals have shown that mass specific cost of transport (J kg−1 m−1) for climbing is independent of body size across species, but little is known about within-species allometry of climbing costs or the effects of difficulty and velocity. Here, we assess the effects of velocity, route difficulty, and anatomical variation on the energetic cost of climbing within humans. Twelve experienced rock climbers climbed on an indoor wall over a range of difficulty levels and velocities, with energy expenditure measured via respirometry. We found no effect of body mass or limb proportions on mass-specific cost of transport among subjects. Mass-specific cost of transport was negatively correlated with climbing velocity. Increased route difficulty was associated with slower climbing velocities and thus higher costs, but there was no statistically significant effect of route difficulty on energy expenditure independent of velocity. Finally, human climbing costs measured in this study were similar to published values for other primates, suggesting arboreal adaptations have a negligible effect on climbing efficiency.