From Concentration to Flux: A Mechanistic Model for Accurate Methane Emission Estimates in Livestock

This dataset contains MATLAB source code used to implement the hybrid multiphysics framework described in the manuscript titled "A Physics-Based Framework for Accurate On-Farm Enteric Methane Sensing." The software models the complete emission-to-sensor pathway for methane released during cattle eructation events, integrating physiological control volume analysis with a transient buoyant puff model.

The main script is MassConservationV05.m, which simulates methane transport through four interconnected control volumes representing the rumen, lungs, local environment, and sampling device. It applies the Reynolds Transport Theorem to derive time-resolved methane concentrations and mass fluxes in each compartment. The second core script is Solve_bovine_puffV04_integration.m, which couples the output of the control volume model to a puff-based fluid dynamics model. This code initializes the puff using integrated physiological parameters and solves a system of ordinary differential equations to predict the spatiotemporal evolution of methane concentration and velocity fields. Two supporting functions are included:

PuffSolver.m: Solves the puff trajectory and concentration field using Gaussian self-similar profiles and conservation laws for momentum, buoyancy, and scalar transport.
BelchProfileGenerator.m: Generates a lognormal flow profile representing the temporal shape of a belching event, which serves as input to the control volume model.

All files are written in MATLAB and are compatible with versions R2021a and later. Users can modify physiological parameters, environmental conditions, and sensor configurations to simulate different scenarios. The software is intended to support researchers working on methane sensing, livestock emissions modeling, and sensor calibration.

To run the full simulation:
Start with MassConservationV05.m to simulate the control volume system.
Then run Solve_bovine_puffV04_integration.m to compute the puff evolution and sensor capture fraction.
Use the supporting functions as needed to customize the emission profile and puff behavior.
This software supports the reproducibility and extension of the results presented in the associated manuscript and is intended for open scientific use.

本数据集包含用于复现题为《面向农场现场肠道甲烷精准传感的物理驱动框架》（*A Physics-Based Framework for Accurate On-Farm Enteric Methane Sensing*）的论文手稿中所述混合多物理场框架的MATLAB源代码。该软件对牛嗳气过程中释放的甲烷从排放到传感的完整路径进行建模，整合了生理控制容积分析与瞬态浮力puff模型。

主脚本为"MassConservationV05.m"，其模拟甲烷在四个相互连通的控制容积间的输运过程，这四个容积分别对应瘤胃（rumen）、肺脏、局部环境与采样装置。该脚本应用雷诺输运定理（Reynolds Transport Theorem），推导各控制容积内随时间变化的甲烷浓度与质量通量。

第二个核心脚本为"Solve_bovine_puffV04_integration.m"，其将控制容积模型的输出与基于puff的流体动力学模型进行耦合。该代码通过整合的生理参数初始化puff团，并求解常微分方程组，以预测甲烷浓度与速度场的时空演化过程。

本数据集包含两个辅助函数：
"PuffSolver.m"：利用高斯自相似剖面（Gaussian self-similar profiles）以及动量、浮力与标量输运守恒定律，求解puff团的轨迹与浓度场。
"BelchProfileGenerator.m"：生成代表嗳气事件时间形态的对数正态流动剖面，作为控制容积模型的输入。

所有代码均采用MATLAB编写，兼容R2021a及更高版本。用户可修改生理参数、环境条件与传感器配置，以模拟不同场景。本软件旨在为开展甲烷传感、畜禽排放建模与传感器校准研究的科研人员提供支持。

如需运行完整仿真，请按以下步骤操作：
首先运行"MassConservationV05.m"以模拟控制容积系统，随后运行"Solve_bovine_puffV04_integration.m"以计算puff团的演化过程与传感器捕获率。可根据需求使用辅助函数自定义排放剖面与puff团行为。

本软件可助力相关论文手稿中所述结果的复现与拓展，且专为开放科学使用而设计。