3,164 research outputs found
Assess and reduce toxic chemicals in bioplastics
No full textAssess and reduce toxic
chemicals in bioplastics
To promote a circular economy and mitigate pollution, the bioplastics industry has
begun to phase out polymers derived from
petrochemicals (1–3). This action is a positive step, but it doesn’t affect the many bioplastics on the market, which also contain
potentially harmful additives. Given that
bioplastics will likely replace polymers, it is
crucial to determine which bioplastics cause
the least harm.
Components of bioplastics can leak into
the environment. After disposal, weathering and ultraviolet degradation lead to
additional release of chemicals (4). When
determining the safety of plastic materials,
it is important to consider that such leakage
could have adverse effects on ecosystems,
wildlife, and humans (5–8).
Discarded plastics often end up in the
ocean, where chemicals leaking into the
aqueous environment are toxic to marine
life. Additives such as phthalates from
starch- and cellulose-based bioplastics can
also leak into marine environments through
wastewater and runoff from landfills. The
chemicals affect bioluminescent bacteria
and the development of sea urchin larvae
(5–7). Bio-cups, bio-polyethylene bottles, and
bioplastic supermarket bags are produced
with polylactide (PLA), a polyester derived
from renewable biomass. PLA contains
chemicals of emerging concern (CECs), such
as bisphenol A, that cause dose-dependent
increases of malformed mussel larvae (8).
More information about the CECs in bioplastics is urgently needed. No protocols are
available to characterize either the chemicals
or the leachate of chemicals from conventional and bio-based plastics (9), making
evidence-based, environmentally responsible
management impossible. Manufacturers of
plastic items and their consultants should
be required to test for molecular, organismal, and population-level effects and make
public the risks of each type of both conventional plastic and bioplastic (10). Integrated
chemical and biological approaches should
be used to assess the risks associated with
low-level exposures to CECs released by bioplastics as well as their possible combined
effects in mixtures. Assessing the toxicity of
CECs that migrate from bioplastics into the
surrounding environment could help determine how to prevent unexpected adverse
health outcomes (11).
Instead of replacing one harmful material
with another, the bioplastic industry and
researchers should work together to identify
the safest and most sustainable plastic alternatives (6). Creating and prioritizing the production of nontoxic materials with a low carbon footprint could lead to a reduced need
for landfills and less ocean plastic waste
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Biomass-Derived Activated Carbon Through Self-Activation Process
No full textSelf-activation is a process that takes advantage of the gases emitted from the pyrolysis process of biomass to activate the converted carbon. The pyrolytic gases from the biomass contain CO2 and H2O, which can be used as activating agents. As two common methods, both of physical activation using CO2 and chemical activation using ZnCl2 introduce additional gas (CO2) or chemical (ZnCl2), in which the CO2 emission from the activation process or the zinc compound removal by acid from the follow-up process will cause environmental concerns. In comparison with these conventional activation processes, the self-activation process could avoid the cost of activating agents and is more environmentally friendly, since the exhaust gases (CO and H2) can be used as fuel or feedstock for the further synthesis in methanol production. In this research, many types of biomass were successfully converted into activated carbon through the self-activation process. An activation model was developed to describe the changes of specific surface area and pore volume during the activation. The relationships between the activating temperature, dwelling time, yield, specific surface area, and specific pore volume were detailed investigated. The highest specific surface area and pore volume of the biomass-derived activated carbon through the self-activation process were up to 2738 m2 g-1 and 2.209 cm3 g-1, respectively. Moreover, the applications of the activated carbons from the self-activation process have been studied, including lithium-ion battery (LIB) manufacturing, water cleaning, oil absorption, and electromagnetic interference (EMI) shielding
Assessment of Self-Archiving in Institutional Repositories: Depositorship and Full-Text Availability
No full textThis research evaluates the success of open access self-archiving in several well-known institutional repositories. Two assessment factors have been applied to examine the current practice of self-archiving: depositorship and the availability of full text. This research discovers that the rate of author self-archiving is low and that the majority of documents have been deposited by a librarian or administrative staff. Similarly, the rate of full-text availability is relatively low, except for Australian repositories. By identifying different practices of self-archiving, repository managers can create new strategies for the operation of their repositories and the development of archiving policies
code and data for Xia et al. (2022) GBC
No full text1. The R code for two-season water storage model with isotopic fluxes. It can be run without any package (but it may contain screen dimension errors). It reproduces Figure 12 in the paper.2. The site-specific 12 monthly means (both RP and CV) of isotope data and raw weekly precipitation d-excess data from USNIP program from 1989-2001.If you have any question, please contact the lead author (Zhengyu Xia, zhyxia[at]hotmail.com). If you intend to use and work with USNIP data, please contact Jeff Welker (jmwelker[at]alaska.edu).</div
Skyrmion-skyrmion and skyrmion-edge repulsions in skyrmion-based racetrack memory
No full textMagnetic skyrmions are promising for building next-generation magnetic memories and spintronic devices due to their stability, small size and the extremely low currents needed to move them. In particular, skyrmion-based racetrack memory is attractive for information technology, where skyrmions are used to store information as data bits instead of traditional domain walls. Here we numerically demonstrate the impacts of skyrmion-skyrmion and skyrmion-edge repulsions on the feasibility of skyrmion-based racetrack memory. The reliable and practicable spacing between consecutive skyrmionic bits on the racetrack as well as the ability to adjust it are investigated. Clogging of skyrmionic bits is found at the end of the racetrack, leading to the reduction of skyrmion size. Further, we demonstrate an effective and simple method to avoid the clogging of skyrmionic bits, which ensures the elimination of skyrmionic bits beyond the reading element. Our results give guidance for the design and development of future skyrmion-based racetrack memory
Gao du yue shu xia de tuan liu re dui liu shu zhi yan jiu
No full textChong, Kai Leong = 高度約束下的湍流熱對流數值研究 / 莊啟亮.Thesis M.Phil. Chinese University of Hong Kong 2014.Includes bibliographical references (leaves 37-40).Abstracts also in Chinese.Title from PDF title page (viewed on 26, September, 2016).Chong, Kai Leong = Gao du yue shu xia de tuan liu re dui liu shu zhi yan jiu / Zhuang Qiliang
You ke tie jing: Liu juan. v.1
No full text夏鼎著.框18x13公分, 9行24字, 小字雙行同, 左右雙邊, 單黑魚尾, 版心上鐫書名, 中鐫卷次, 下鐫頁次."光緒二十二季春八月廣雅書局校刊"--內封面背頁.On double leaves, oriental style.Xia Ding zhu.Kuang 18x13 gong fen, 9 hang 24 zi, xiao zi shuang hang tong, zuo you shuang bian, dan hei yu wei, ban xin shang juan shu ming, zhong juan juan ci, xia juan ye ci."Guangxu er shi er ji chun ba yue Guang ya shu ju jiao kan"--Nei feng mian bei ye
Factors to Assess Self-Archiving in Institutional Repositories
No full textThis paper proposes a group of factors that may be used to assess the success of open access self-archiving. It concentrates on self-archiving in institutional repositories. The authors emphasize the importance of examining content materials, particularly the availability of full text versus abstracts and the deposits archived by authors versus by others.Peer reviewe
[[alternative]]The development and industrialization of apple cultivation in Qi-Xia, China
No full text[[abstract]]This study focused on the concept of agricultural system as a research structure, so the researcher personally went to Mainland China for field investigaion and had chosen the Qi-Xia city as a study area to understand apple production. The purposes of this thesis were to study the transformation process of specialized agriculture areas, causes of agro-economic activity, industrializing development, and the effects of globalization on apple production.
The Huang-Jia-Zhuang in Qi-Xia was selected as a case study, using agricultural system to analyze the importation of Fuji apple specie for Qi-Xia farmers and the utilization of land with regards to the apples. The farmers’ cognition and expertise in cultivating Fuji apples, their economic condition, government’s reservation policy for cultivated-land, and the quality of the soil were basic considerations to initiate the farmers to apply different strategic processes in importing Fuji apples. Thus, there were three different types of apples cultivation, including advanced, transitory, and retarded types in the study area.
All of these had shaped the specialized Fuji area, and changed the land use types. As a result, there were altering farmland scenic views and farmers’life styles, and creating a commercial site in the village. In addition, there were causing swift increase in production and upgrading quality, and marking a new step into the development of apple transportation’s complete system.
After China’s trade liberation and entry into the WTO, local and international corporations have increased their investment on Qi-Xia’s apple industry as well as increased cooperation with the farmers. Thus, there were producing high quality Fuji apples for export, shaping an unique operational process, and allowing the Qi-Xia to represent a more complete specialized apple-cultivated area.
Direct numerical simulation of weakly spanwise-rotating turbulent plane Couette flow
No full textIn this report, we conduct direct numerical simulations (DNS) of weakly spanwise-rotating plane Couette flows at Reynolds number (here, is the half the wall velocity difference, and is half-channel height). A series of simulations with different rotation numbers ( is constant angular velocity component in the spanwise direction) is carried out to investigate the effect of on the flow statistics. Our results show that the flow statistics are affected by the , and a "critical" rotation number (between and ) is observed, where the kinetic energy of secondary flow contributes about a half of the turbulent kinetic energy, and the mean shear rate at the center line reaches a minimum value. We conjecture that different mechanisms should exist around , and will be investigated further
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