GREENHOUSE GAS AND AMMONIA EMISSION MITIGATION PRIORITIES FOR UK POLICY TARGETS

Agriculture is essential for providing food and maintaining food security while concurrently delivering multiple other ecosystem services. However,agricultural systems are generally a net source of greenhouse gases and ammonia. They, therefore, need to substantively contribute to climate change mitigation and net zero ambitions. It is widely acknowledged that there is a need to further reduce and mitigate emissions across sectors, including agriculture to address the climate emergency and emissions gap. This discussion paper outlines a collation of opinions from a range of experts within agricultural research and advisory roles following a greenhouse gas and ammonia emission mitigation workshop held in the UK in March 2022. The meeting identified the top mitigation priorities within the UK's agricultural sector to achieve reductions in greenhouse gases and ammonia that are compatible with policy targets. In addition, experts provided an overview of what they believe are the key knowledge gaps, future opportunities and cobenefits to mitigation practices as well as indicating the potential barriers to uptake for mitigation scenarios discussed.

Water quality induced corrosion of stainless steel valves during long-term service in a reverse osmosis system

The current study analyzes the contribution of 10 water quality parameters(including pH,turbidity,conductivity,total dissolved solids(TDS),hardness,total organic carbon(TOC),alkalinity,calcium ions,chlorides and sulfates) to corrosion extent of stainless steel valves taken from different locations in a reverse osmosis system of a reclaimed water plant.The valves were in service for 5 years.Raman spectroscopy and X-ray photoelectron spectroscopy analyses are conducted to quantify corrosion products on different valves under various water quality conditions.On that basis,bivariate and multivariate regression analyses between the 10 water quality parameters and the corrosion extent of valve specimens(represented by metal loss percentage(MLP) values) are carried out to check the contribution of those water quality parameters to MLP.The results indicate that the proportions of metal oxides as corrosion products vary according to the corrosion extent of the valves.Although no linear correlation is founds all 10 water quality parameters except for pH show a significant positive correlation with the MLP values of the valve specimens.Moreover,results of multivariate regression suggest that the variation of MLP can be explained by turbidity,TDS,TOC and sulfates.A positive contribution of turbidity,TDS and TOC to MLP is observed,whereas the contribution of sulfates is negative.The results from the current work help to identify the reasons for water quality-induced failure of stainless steel equipment in RO systems.

Stainless steel corrosion scale formed in reclaimed water： Characteristics, model for scale growth and metal element release

Stainless steels generally have extremely good corrosion resistance, but are still susceptible to pitting corrosion. As a result, corrosion scales can form on the surface of stainless steel after extended exposure to aggressive aqueous environments. Corrosion scales play an important role in affecting water quality. These research results showed that interior regions of stainless steel corrosion scales have a high percentage of chromium phases. We reveal the morphology, micro-structure and physicochemical characteristics of stainless steel corrosion scales. Stainless steel corrosion scale is identified as a podiforrn chromite deposit according to these characteristics, which is unlike deposit formed during iron corrosion. A conceptual model to explain the formation and growth of stainless steel corrosion scale is proposed based on its composition and structure. The scale growth process involves pitting corrosion on the stainless steel surface and the consecutive generation and homogeneous deposition of corrosion products, which is governed by a series of chemical and electrochemical reactions. This model shows the role of corrosion scales in the mechanism of iron and chromium release from pitting corroded stainless steel materials. The formation of corrosion scale is strongly related to water quality parameters. The presence of HCIO results in higher ferric content inside the scales. Cl- and SO2- ions in reclaimed water play an important role in corrosion pitting of stainless steel and promote the formation of scales.

美国高校捐赠基金为何陷入两极分化困局？

莫尔豪斯学院（Morehouse College）拥有强大的学术能力，田园诗般绿树成荫的校园，人才辈出的校友，其中15％的校友给学校捐款，比率与哈佛大学相当。但作为亚特兰大地区一所传统黑人学院，该校欠缺一样越来越重要的东西：一个财力雄厚的捐赠基金。这所全男生学院的捐赠基金规模仅略超1．3亿美元．在全美大学排名第400位左右。对于传统黑人学院和大学（也被称为HBCU）而言，这并不罕见。