environmental challenge
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Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4306
Author(s):  
Wanna Bai ◽  
Jie Guan ◽  
Huan Liu ◽  
Shihong Cheng ◽  
Fuchun Zhao ◽  
...  

Natural rubber (NR) as a renewable biopolymer is often produced by acid coagulation of fresh natural latex collected from Hevea brasiliensis. However, this traditional process is facing a huge economic and environmental challenge. Compared with the acid coagulation, spontaneous or microorganism coagulation is an ecofriendly way to obtain NR with excellent performance. To clarify the influence of different sugars on NR quality, several sugars were used to assist the coagulation process. Influence of different sugars on microstructure and cold crystallization were examined by 1H NMR, DSC, etc. The results indicated that sugars exhibit different biological activity on terminal components of fresh field latex and can influence the resultant molecular structure and basic properties. Brown sugar exhibits higher metabolic activity and is inclined to decompose the protein and phospholipids crosslinking compared with other sugars. The larger molecular weight of sugar molecule is beneficial for the formation of the stable α lamellae phase and higher overall degree of crystallization.


Author(s):  
Patricia De Francisco ◽  
Ana Martín-González ◽  
Daniel Rodriguez-Martín ◽  
Silvia Díaz

Arsenic (As) is quite an abundant metalloid, with ancient origin and ubiquitous distribution, which represents a severe environmental risk and a global problem for public health. Microbial exposure to As compounds in the environment has happened since the beginning of time. Selective pressure has induced the evolution of various genetic systems conferring useful capacities in many microorganisms to detoxify and even use arsenic, as an energy source. This review summarizes the microbial impact of the As biogeochemical cycle. Moreover, the poorly known adverse effects of this element on eukaryotic microbes, as well as the As uptake and detoxification mechanisms developed by yeast and protists, are discussed. Finally, an outlook of As microbial remediation makes evident the knowledge gaps and the necessity of new approaches to mitigate this environmental challenge.


2021 ◽  
Vol 6 ◽  
pp. 313
Author(s):  
Michael Ambler ◽  
Timna Hitrec ◽  
Anthony Pickering

Torpor is a hypothermic, hypoactive, hypometabolic state entered into by a wide range of animals in response to environmental challenge. This review summarises the current understanding of torpor. We start by describing the characteristics of the wide-ranging physiological adaptations associated with torpor. Next follows a discussion of thermoregulation, control of food intake and energy expenditure, and the interactions of sleep and thermoregulation, with particular emphasis on how those processes pertain to torpor. We move on to take a critical view of the evidence for the systems that control torpor entry, including both the efferent circulating factors that signal the need for torpor, and the central processes that orchestrate it. Finally, we consider how the putative circuits responsible for torpor induction integrate with the established understanding of thermoregulation under non-torpid conditions and highlight important areas of uncertainty for future studies.


2021 ◽  
Author(s):  
Muhammad Ikhsan Akbar ◽  
Jerry Tobing ◽  
Mohd Zarir Bin Musa ◽  
Irshad Fajar ◽  
Fajar Ardiansyah

Abstracts Conductor setting depth is critical to provide structural support for next drilling sections. The shoe strength must suffice for drilling ahead and avoid any washout and unstable zone. The objective is to design and run conductor smoothly in regards to engineering and operation aspect. Multidisciplinary approach including geotechnical, drilling engineering, and structure, was implemented during planning strategy. The pre-determined conductor setting depth was defined on the maximum mud weight to be used during drilling surface hole section in accordance to the formation strength below the conductor with the purpose of not inducing losses to the formation. Lateral distance between conductor and platform jacket pile was also analyzed to secure the jacket integrity. Anti-collision analysis was performed to prevent collision due to the existence of production well in same platform. Conductor pipe size and specification with some feature was defined to withstand under anticipated load and environment. To determine the way to achieve target depth and the suitability of hammer type, drivability analysis was performed with various anticipated condition. Considering shallow refusal depth, drill and drive was required to reduce shaft friction of soil. Another environmental challenge arise during conductor operation was unable to contain fluid and cutting returns from clean-out process causing return to cover part of the production platform facility. Some of technology were planned to mitigate this challenge. By having comprehensive conductor design, the conductor pipe in all four wells drilled has been successfully installed without any problem on platform jacket integrity and subsequent drilling section. This approach also enabled to efficiency of conductor installation where the number of clean-out and driving run could be reduced. The overflow return challenge could be fully contained by utilizing selfdesigned equipment. The overall operation days of conductor has shown improvement with 1.02 saving days on the last well which equivalent to amount of cost saving around USD 203,500.


2021 ◽  
Vol 6 (1) ◽  
pp. 65-81
Author(s):  
Robert Smith

The farming Industry and rural locations are increasingly being targeted by predatory environmental criminals but as will be demonstrated there is also an insider element to environmental crimes. Such criminal activities pose an environmental challenge and require creative solutions. Indeed, the notion of the farmer as an environmental criminal is a contentious addition to the typology of rural criminals. Traditionally, environmental crime was an overlooked and under researched category of criminology, primarily because 'farmers' as a genre were treated with an elevated level of societal respect in line with their 'idyllic' portrayal. They do not fit accepted social constructs and stereotypes of the urban based criminal fraternity. Consequentially, we heard little of the stereotype of the 'bad' farmer. Recent years have seen a rise in public interest and concern relating to ethical aspects of farming leading to a raising of public awareness. Farmers are no longer immune from criticism, nor prosecution. Using documentary research methods this study reports on several high-profile cases at the nexus and reveals an updated typology of rural environmental crimes and criminals.


Author(s):  
Minami Koriyama ◽  
Yoshitaka Okamoto ◽  
Takeshi Suzuki ◽  
Tomohisa Iinuma ◽  
Heizaburou Yamamoto ◽  
...  

2021 ◽  
Vol 13 (17) ◽  
pp. 9488
Author(s):  
Addam Claes ◽  
Lucy Melchi ◽  
Sibel Uludag-Demirer ◽  
Goksel N. Demirer

Due to its high water and organic contents, management of apple pomace (AP) poses several waste management challenges on the apple juice and cider producing industries. Bioconversion of AP into biogas provides an excellent possibility to reduce the environmental challenge faced in the management of AP waste along with producing renewable energy in the form of methane. This study investigated the effect of carbon-based conductive materials (biochar and graphene) and trace metals supplementation to improve biogas production from AP. The results indicate that supplementation of biochar, trace metals, and graphene significantly improves the biogas production from AP. Trace metal and biochar supplementation at a COD concentration of 6000 mg/L resulted in 7.2% and 13.3% increases in the biogas production, respectively. When trace metals and biochar were supplemented together, the biogas production increased by 22.7%. This synergistic effect was also observed at the COD concentration of 12,000 mg/L. The improvement in the biogas formation was significantly higher for graphene supplemented reactors (27.8%). Moreover, biochar and trace metals supplementation also led to 19.6% and 23.0% increases in the methane yield relative to the reactor fed only with AP, respectively. These results suggest anaerobic digestion supplemented with carbon-based conductive materials and trace metals is a viable option for valorizing apple pomace.


Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 5051
Author(s):  
John Owens ◽  
Ang Xiao ◽  
Jason Bonk ◽  
Michael DeLorme ◽  
Agnes Zhang

For many years, SF6 has been the preferred dielectric medium in electrical power applications, particularly in high voltage gas-insulated equipment. However, with the recognition that SF6 has an extremely long atmospheric lifetime and very high global warming potential, governments have pursued emission reductions from gas-filled equipment. The electrical power industry has responded to this environmental challenge applying SF6-free technologies to an expanding range of applications which have traditionally used SF6, including gas-insulated switchgear, gas-insulated circuit breakers and gas-insulated lines or bus bars. Some of these SF6-free solutions include gas mixtures containing fluorinated compounds that have low climate impact, among them, a fluoronitrile and a fluoroketone developed as 3M™ Novec™ 4710 Insulating Gas and 3M™ Novec™ 5110 Insulating Gas, respectively. Both fluoronitrile and fluoroketone mixtures are successfully used in gas-insulated equipment currently operating on the grid where they reduce greenhouse gas emissions by more than 99% versus SF6. This paper reviews these leading components of alternative-gas mixtures with updates on the performance, safety and environmental profiles in electrical power applications.


2021 ◽  
pp. 355-404
Author(s):  
Alan Boyle ◽  
Catherine Redgwell

This chapter looks, inter alia, at how international law has been used or could be used to help tackle the most significant environmental challenge of our time. This challenge is global climate change. Not many topics provide a good illustration of the importance of a globally inclusive regulatory regime focused on preventive and precautionary approaches to environmental harm—or of the problems of negotiating one on such a complex subject. Solutions to global climate change have not been easily forthcoming. The chapter looks at the efforts of the international regulatory regime to address these challenges by recourse to novel ‘market based’ mechanisms and differential treatment. An example is the post-Kyoto scheme for reducing greenhouse gas emissions through ‘nationally determined contributions’. In the end, the chapter argues, it is likely to be technology that enables us to grapple with the causes of climate change, not law, but law can drive technological change, as it has with ozone depletion and acid rain.


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