Energy security concerns and the need for mitigation of environmental impacts associated with energy generation from fossil fuels (e.g., greenhouse gas emissions), has accelerated the deployment of ...renewable fuels such as biogas. The objective of this study was to conduct an attributional Life Cycle Assessment (LCA) of multiple biogas production and utilization pathways in order to identify areas where further mitigation of potential environmental impacts could be realized to enhance environmental sustainability of biogas deployment. The LCA of pre-defined small (<500 kW
el) and large-scale (≥500 kW
el) biogas systems was conducted in accordance with the ISO 14040 standards, using SimaPro 7.2 computer software. The functional unit was the anaerobic digestion of 1 tonne of feedstock mixture to produce biogas with the digestate as process end product with multiple utilization options. The analyses quantified the impacts of feedstock type (both single feedstock and co-digestion), biogas utilization pathways, and the digestate processing and handling unit processes. Analyses also considered the replacement of fossil fuels and chemical fertilizer with equivalent energy value of the biogas and nutrient content of the digestate, respectively.
The recorded variations in life-cycle impact categories for the scenarios compared indicated the importance of judicious selection of biogas pathways for environmental impact mitigation. The LCA and life-cycle energy analyses for single feedstock scenarios considered indicated that straw and corn silage as most efficient feedstocks for biogas. For example, straw mixture improved the environmental performance by almost 830% compared to the base scenario of cattle manure feedstock. This was mainly ascribed to the higher energy density, which exceeded the primary energy inputs for feedstock supply logistics. In order to minimize the environmental damage associated with feedstock type in all impact categories considered, and simultaneously maintain a positive energy balance, the analyses suggest that co-digestion of Municipal Solid Waste (MSW) with agricultural and food industry residues are most appropriate for both small and large-scale biogas plants; co-digestion of waste and residues accounted for just 1% of the estimated impacts on agricultural land occupation, compared to the co-digestion of predominantly energy crop feedstock, and also reduced the climate change impacts by up to 30%.
The results also indicated for the small-scale plants, the most promising pathway for sustainable biogas utilization would be in tri-generation; compared to electricity only generation in Combined Heat and Power (CHP), tri-generation could reduce the overall environmental impact by almost 200%. For the scenarios that included purification and upgrading biogas to biomethane for gas grid injection (arguably the most promising technology that could support rapid utilization expansion), it was noted that only the scenario with coupled small-scale CHP unit covering internal heat demands was capable of reducing the overall impact on fossil fuel depletion, compared to electricity generation alone. This was explained by the higher potential for fossil fuel substitution with biomethane, due to higher conversion efficiency (ca. 100%). It was also found that, the recovery of residual biogas from digestate storage reduced the environmental impacts of digestate management process by ca. tenfold, due to combined reduction of the potential biogas leakage to the atmosphere and subsequent use of the extra yield for energy generation.
A Life Cycle Inventory (LCI) was developed to identify the unit processes in the life-cycle of biogas production and utilization offering the greatest opportunities for emission to air reduction, ...hence potential for environmental improvement. The systems investigated included single feedstock digestion and multiple feedstock co-digestion, small (<500
kW
el) and large-scale (≥500
kW
el) biogas plants, and selected biogas utilization pathways and digestate management options. Analysis was performed in accordance with ISO 14040 and 14044 standards, using SimaPro 7.2 software and Ecoinvent
® v2.1 database. The analysis is based on published data considering primarily conditions for Germany. Results indicated significant variation of emission levels for all unit processes related to biogas production and utilization. Emissions from the feedstock supply logistics were highly influenced by the origin of feedstock used. For example, the fossil fuel related carbon dioxide (CO
2,fossil) emissions associated with feedstock supply were over 50 times higher for Municipal Solid Waste (MSW) compared to cattle manure. The higher value for MSW was associated with the requisite collection, transport and pre-treatment, whereas only transportation was required for cattle manure. Emissions from unit processes in biogas plant operation and biogas utilization depended on combined efficiency of energy generation (electricity and thermal), potential substitution of fossil fuels with biogas and utilization of the heat by-product of electricity generation. For example, the results indicated that upgrading of biogas to biomethane, with almost 100% conversion efficiency, caused 6 times less non-methane volatile organic compounds (NMVOC) emissions if plant heating was supplied from coupled small-scale CHP unit as opposed to heating with natural gas. Harnessing of the residual biogas from digestate storage areas was estimated to reduce methane emission by a factor up to 14. Overall, this study provides basic data required for identification and mitigation of emission ‘hot-spots’ in biogas production and utilization, including the evaluation of environmental and public health impacts of biogas technology options by attributional Life Cycle Assessment (LCA) methodology.
The prospects for expanded utilization of biogas systems in German was analysed, by identifying the operational and policy factors affecting the complete chain of processes from implementation ...process for biogas plants, through to biogas production and utilization. It was found that the Renewable Energies Act (EEG) and energy tax reliefs provide bases for the support of expanded utilization. Upgrading of biogas to natural gas quality for utilization in the transportation sector was arguably the most promising technology that could support rapid utilization expansion. Sustainable deployment of biogas systems in light of the unstable feedstock prices and availability, and the need for subsidy-free operation in the long term requires; enhancement of feedstock flexibility and quality characteristics to maximise gas yield, and optimisation of the anaerobic digestion process management. Assessment of energy balance and potential environmental impacts of the integrated process chain provides a holistic assessment of sustainability. The results also support the development and foster of policies and framework for development of biogas as environmentally friendly energy resource, among a mix of renewable energy sources, hence, compete favourably with fossil fuels to enhance the prospects for expanded utilization.
Purpose
Shear-mediated thrombosis is a clinically relevant phenomenon that underlies excessive arterial thrombosis and device-induced thrombosis. Red blood cells are known to mechanically contribute ...to physiological hemostasis through margination of platelets and vWF, facilitating the unfurling of vWF multimers, and increasing the fraction of thrombus-contacting platelets. Shear also plays a role in this phenomenon, increasing both the degree of margination and the near-wall forces experienced by vWF and platelets leading to unfurling and activation. Despite this, the contribution of red blood cells in shear-induced platelet aggregation has not been fully investigated—specifically the effect of elevated hematocrit has not yet been demonstrated.
Methods
Here, a microfluidic model of a sudden expansion is presented as a platform for investigating platelet adhesion at hematocrits ranging from 0 to 60% and shear rates ranging from 1000 to 10,000 s
−1
. The sudden expansion geometry models nonphysiological flow separation characteristic to mechanical circulatory support devices, and the validatory framework of the FDA benchmark nozzle. PDMS microchannels were fabricated and coated with human collagen. Platelets were fluorescently tagged, and blood was reconstituted at variable hematocrit prior to perfusion experiments. Integrin function of selected blood samples was inhibited by a blocking antibody, and platelet adhesion and aggregation over the course of perfusion was monitored.
Results
Increasing shear rates at physiological and elevated hematocrit levels facilitate robust platelet adhesion and formation of large aggregates. Shear-induced platelet aggregation is demonstrated to be dependent on both α
IIb
β
III
function and the presence of red blood cells. Inhibition of α
IIb
β
III
results in an 86.4% reduction in overall platelet adhesion and an 85.7% reduction in thrombus size at 20-60% hematocrit. Hematocrit levels of 20% are inadequate for effective platelet margination and subsequent vWF tethering, resulting in notable decreases in platelet adhesion at 5000 and 10,000 s
-1
compared to 40% and 60%. Inhibition of α
IIb
β
III
triggered dramatic reductions in overall thrombus coverage and large aggregate formation. Stability of platelets tethered by vWF are demonstrated to be α
IIb
β
III
-dependent, as adhesion of single platelets treated with A2A9, an anti-α
IIb
β
III
blocking antibody, is transient and did not lead to sustained thrombus formation.
Conclusions
This study highlights driving factors in vWF-mediated platelet adhesion that are relevant to clinical suppression of shear-induced thrombosis and in vitro assays of platelet adhesion. Primarily, increasing hematocrit promotes platelet margination, permitting shear-induced platelet aggregation through α
IIb
β
III
-mediated adhesion at supraphysiological shear rates.
Credit for Dummies Ward, Shane
The Journal of philosophy,
04/2024, Letnik:
121, Številka:
4
Journal Article
Recenzirano
A popular view is that you deserve credit for a successful performance only if you were aware in some way of what you were doing. It has been argued that some such cognitive condition on creditworthy ...performance must be true because it is the only way to ensure that one’s success is not an accident. In this paper, I argue against cognitive conditions on creditworthy performance: cognitive conditions are false because there are agents who deserve credit for their successful performances even though they had no idea what they were doing. After presenting my argument and defending it against possible replies, I explore broader implications of the falsity of cognitive conditions in the philosophy of action and of moral worth. I then close by presenting an alternative account of creditworthy performance that explains why success can be non-accidental even if one was not aware of what they were doing.
Deviant causal chain problems arise in many settings. The most famous instance of the problem is the Gettier problem, but the problem also arises in the philosophy of action and perception. Usually, ...attempts to tackle these problems try to solve them individually. This paper takes a different approach: I propose a general solution to the problem. I begin by providing a solution to the deviant causal chain problem for skillful performance, and I argue that the solution can be extended to solve the Gettier problem and the deviant causal chain problems for perception and intentional action. As I develop my solution to these problems, I also compare it with other solutions to bring out the advantages of my approach. I then explain why the solution generalizes: my solution provides us with an analysis of disposition manifestation, which is the key to ruling out deviance. I conclude by considering objections and giving my replies.
IntroductionPeople from Black African Diaspora Communities (BAFDC) experience poorer health outcomes, have many long-term conditions and are persistently under-represented in health and care ...research. There is limited focus on programmes, or interventions that support inclusion and participation of people from BAFDC in research. Through coproduction, this realist review seeks to provide a programme theory explaining what context and mechanisms may be required, to produce outcomes that facilitate inclusion and participation for people from BAFDC in health and care research, in the UK.Methods and analysisA group of people from BAFDC with lived and professional experience, representing all levels of the health and care research system, will coproduce a realist review with a team of African-Caribbean, white British and white British of Polish origin health and care researchers. They will follow Pawson’s five steps: (1) shaping the scope of the review; (2) searching for evidence; (3) document selection and appraisal; (4) data extraction and (5) data synthesis. The coproduction group will help to map the current landscape, identifying key issues that may inhibit or facilitate inclusion. Data will be extracted, analysed and synthesised following realist logic analysis, identifying and explaining how context and mechanisms are conceptualised in the literature and the types of contextual factors that exist and impact on inclusion and participation. Findings will be reported in accordance with Realist and Meta-narrative Evidence Synthesis Evolving Standards .Ethics and disseminationThe coproduction group will agree an ethical approach considering accountability, responsibility and power dynamics, by establishing a terms of reference, taking a reflexive approach and coproducing an ethical framework. Findings will be disseminated to BAFDC and the research community through arts-based methods, peer-reviewed publications and conference presentations, agreeing a coproduced strategy for dissemination. Ethical review is not required.PROSPERO registration numberCRD42024517124.
This project developed a cost model for the mechanical harvesting of fast-growing Eucalyptus plantations. With such a model, forest managers can check the profitability of a prospective operation ...under different work conditions and assess the competitiveness of alternative options, which in turn will lead to supply chain optimization. The model is based on mathematical relationships that return machine productivity as a function of operational conditions. These relationships were calculated on data obtained from detailed time studies, conducted on all the main equipment types used in Eucalyptus plantations. Tests were conducted on 11 different machines that harvested a total 2465 oven-dry tonnes over 23
ha on 12 sites in 3 countries. The time study sessions lasted 250
h. Both the Cut-to-Length (CTL) system and the Whole-Tree (WT) system were studied. The model was validated with success and was used to make a number of different simulations. Simulation results show that the WT system allows cheaper harvesting and transport than the CTL system for a range of conditions. Under the conditions of our simulations and in favourable terrain, WT harvesting results in a delivered cost of about 20
euro/green tonne of bark-free pulp chips, whereas CTL harvesting results in a cost between 25 and over 30
euro/green tonne of debarked pulp roundwood.
There are reasons for many things. For instance, we can have reasons to watch our favorite movie and believe that it will live up to the hype. These are cases of reasons for beliefs and actions. We ...can also have reasons for affective attitudes: we can have reasons to be excited the movie is releasing, to fear that our friends won't like it as much as we do, and to be relieved that they did. Barry Maguire has recently argued against the claim that there are reasons for affective attitudes. If he is right, it would have serious consequences in metaethics. Several projects in metaethics are committed to the existence of reasons for affective attitudes. These views are doomed if Maguire is right. Other projects have run into serious difficulties in trying to account for the existence of reasons for attitudes. Their prospects are seriously improved if Maguire is right. I hope to show we should not accept these consequences: the existence of reasons for attitudes can be defended against Maguire's attack.
A method for estimating the three-dimensional (3D) footprint of a 16.9R38 pneumatic tyre was developed. The method was based on measured values of contact pressure at the soil–tyre interface and ...wheel contact length determined from the contact pressures and the depths and widths of ruts formed in the soil. The 3D footprint was investigated in an area of the field where the pressure sensors of the tyre passed in a soft clay soil. The tyre was instrumented with six miniature pressure sensors, three on the lug face and the remaining three on the under-tread region between two lugs. The instrumented tyre was run at a constant forward speed of 0.27
m/s and 23% slip on a soft soil, 0.48
MPa cone index, 25.6% d.b. moisture content for four wheel load and tyre pressure combination treatments. The 3D footprint assessment derived from soil–tyre interface stress used in this research is a unique methodology, which could precisely relate the trend profile of the 3D footprint to the measured rut depth. The tyre–soil interface contact pressure distributions results showed that as inflation pressure increased the soil strength increased significantly near the centre of the tyre as a compaction increase sensed with the cone penetrometer.
