446494 research outputs found
Sort by
Quantification of Household Greenhouse Gas Emissions in Mumbai: A Scope 1, 2, and 3 Analysis
No full textGreenhouse gas (GHG) emissions are one of the major causes of climate change. These GHG emissions are generated by a number of sources, ranging from simple electricity usage to product and service production and recycling used by consumers. This paper calculates the GHG emissions of an average household in Mumbai, India, using the Greenhouse Gas Protocol. This categorizes the emissions into 3 scopes: Scope 1 (direct emissions), Scope 2 (indirect emissions), and Scope 3 (value chain emissions). This paper adapts this protocol to a household scale and calculates the monthly CO2 equivalent emissions through a thorough survey, activity data, emission factors, and complex calculations. This paper introduces a holistic yet innovative approach to the calculation of monthly GHG emissions while following the globally accepted standards defined by the GHG protocol. The data-driven findings enable the detection of prominent sources of emissions, offer practical suggestions, and develop sustainable models for living in urban areas to combat climate change
The sustainability of financing for the demining process in Ukraine's territory
No full textThe article considers the possibility of integrating demining efforts with economic recovery and sustainable development initiatives. For this purpose innovative financial models such as Outcomes-Based Financing, Outcome-Based Public-Private Partnerships and Sustainability-Linked Bonds are proposed that can provide sustainable financing beyond traditional humanitarian aid. The potential to attract diverse sources of capital and to overcome funding gaps is demonstrated by these mechanisms, with demining transformed from a costly humanitarian operation into a strategic investment. Specific recommendations are provided for creating a favourable regulatory environment, prioritizing economically significant work, and strengthening international coordination. The main conclusion is that the transformation of approaches to financing is deemed essential for ensuring Ukraine's comprehensive post-war recovery and prosperity
Effect of Precast Concrete Walls on the Behavior of Mortar-Filled Steel Hollow Section Frames
No full textThis research aims to investigate the effect of precast concrete walls on the behavior of mortar-filled steel hollow section frames. Two frames, one with walls and one without, were constructed and tested under pushover loading. The results show that incorporating precast walls significantly increases load-bearing capacity and structural stiffness, but decreases ductility. The frame with precast walls was able to withstand a maximum load of 56.742 kN with a deformation of 6.97 mm, while the frame without walls could only handle a maximum load of 34.182 kN with a deformation of 18.5 mm. The ductility analysis shows that the structure with precast walls has a ductility index of 1.163, while the frame without walls achieves a value of 2.68. The lower ductility in the structure with walls is due to its higher stiffness, which causes faster strength degradation after reaching peak capacity. This shows the typical features of precast walls, where increased stiffness and load capacity often limit inelastic deformation. Generally, this research confirms that adding precast walls to hollow section stell frames can effectively enhance their strength and stiffness in resisting lateral loads
Terahertz metasurface enabled by barium strontium titanate ferroelectric film
No full textIn this paper, a Ba0.5Sr0.5TiO3 (BST) ferroelectric film is prepared and characterized in the terahertz band. Subsequently, based on the prepared BST film, a metasurface is proposed to manipulate electromagnetic waves. The experimental results indicate that the designed BST metasurface can effectively achieve abnormal beam reflection at around 0.750 THz. Furthermore, by taking advantage of the property that the dielectric constant of the BST film can be altered with an external electric field, a programmable metasurface is proposed. By adjusting the dielectric constant of the BST film, the proposed programmable metasurface can achieve a 1-bit phase response within the frequency range of 0.404-0.410 THz. The far-field simulation results demonstrate that the proposed BST programmable metasurface is capable of realizing dynamic beam steering
Nitsche stabilized virtual element approximations for a Brinkman problem with mixed boundary conditions
No full textIn this paper, we formulate, analyse and implement the discrete formulation of the Brinkman problem with mixed boundary conditions, including slip boundary condition, using the Nitsche’s technique for virtual element methods. We propose a discretization by means of the virtual elements presented in [9]. We derive a robust stability analysis of the Nitsche stabilized discrete scheme for this model problem. We establish optimal a priori error estimates of the discrete scheme with constants independent of the viscosity. Moreover, a set of numerical tests demonstrates the robustness with respect to the physical parameters and verifies the derived convergence results
Projection-free approximation of flows of harmonic maps with quadratic constraint accuracy and variable step sizes
No full textWe construct and analyze a projection-free linearly implicit method for the approximation of flows of harmonic maps into spheres. The proposed method is unconditionally energy stable and, under a sharp discrete regularity condition, achieves second-order accuracy with respect to the constraint violation. Furthermore, the method accommodates variable step sizes to speed up the convergence to stationary points and to improve the accuracy of the numerical solutions near singularities, without affecting the unconditional energy stability and the constraint violation property. We illustrate the accuracy in approximating the unit-length constraint and the performance of the method through a series of numerical experiments, and compare it with the linearly implicit Euler and two-step BDF methods
Self-regulated biological transportation structures with general entropy dissipation: 2D case and leaf-shaped domain
No full textIn recent years, the study of biological transportation networks has attracted significant interest, focusing on their self-regulating, demand-driven nature. This paper examines a mathematical model for these networks, featuring nonlinear elliptic equations for pressure and an auxiliary variable, and a reaction-diffusion parabolic equation for the conductivity tensor, introduced in \cite{portaro2022emergence}. The model, based on an energy functional with diffusive and metabolic terms, allows for various entropy generating functions, facilitating its application to different biological scenarios. We proved a local well-posedness result for the problem in Hölder spaces employing Schauder and semigroup theory. Then, after a suitable parameter reduction through scaling, we computed the numerical solution for the proposed system using a recently developed ghost nodal finite element method \cite{astuto2024nodal}. An interesting aspect emerges when the solution is very articulated and the branches occupy a wide region of the domain
New applications and insights using an old technique
No full textIt has been almost 60 years since the first commercial high-resolution FTIR spectrometer was launched. In gas metrology, such FTIR spectrometers have traditionally been used for a few niche applications, but they have never become a real workhorse. The interest in FTIR has recently revived thanks to new measurement challenges involving multiple reactive gases in applications like CCUS, biogas, and hydrogen quality analysis. However, standard commercial FTIR equipment, such as the gas cell, is typically not fit for purpose for these applications. This paper will discuss some of the necessary modifications to gas cells to exploit the full potential of FTIR as a versatile tool for the selective measurement of reactive gases. Further, common pitfalls in spectral data analysis are discussed. Experimental results on reactive gases in NO2 and CCUS gas standards are presented to show what can be learnt from FTIR measurements. The paper will conclude with an outlook on whether there is a future for FTIR spectrometers with the recent advent of broadband laser spectrometers with similar multicomponent measurement capabilities
Bosch Optical Gas Spectrometer - A New Dimension in Gas Measurement with Raman Spectroscopy
No full textAnalysing the composition of a gas is a complex challenge. Depending on the use case and considering thermodynamic constraints such as gas temperature, gas pressure, and flow rate, various technologies are available. Specific sensors are usually straightforward to use. However, they often have limited concentration ranges and require more or less complex calibration. More sophisticated techniques, such as mass and absorption spectroscopy or gas chromatography, each have their own limitations. Some require ambient pressure, dedicated probe extraction, or time-consuming analysis processes. Raman spectroscopy appears to overcome many of these limitations. However, the Raman effect is so weak that complex and expensive setups are required. To overcome these problems, Bosch developed the BOGS (Bosch Optical Gas Spectrometer). Raman gas spectroscopy is now extremely easy. Gas concentrations as low as 100 ppm can now be detected, and even lower concentrations when the pressure is higher (up to 40 bar) and the detection time is increased from seconds to minutes
Statistics of supermassive black hole gravitational wave background anisotropy
No full textWe investigated the statistical properties of the anisotropy in the gravitational wave (GW) background originating from supermassive black hole (SMBH) binaries. Considering scenarios that include environmental effects and eccentricities of the SMBH binaries, we derived the distribution of the GW anisotropy power spectrum coefficients, Cl ≥ 1/C0. Although the mean of Cl ≥ 1/C0 is the same for all multipoles, we show that their distributions vary, with the low l distributions being the widest. This study finds a strong correlation between spectral fluctuations and anisotropy in the GW signal and shows that the GW anisotropy can break the degeneracy between scenarios that include environmental effects or eccentric binaries. We find that existing NANOGrav constraints on GW anisotropy begin to constrain SMBH scenarios with strong environmental effects