Midpoint Approach Research Articles

Extended life cycle assessment reveals the spatially-explicit water scarcity footprint of a lithium-ion battery storage

The life cycle water scarcity footprint is a tool to evaluate anthropogenic contributions to regional water scarcity along global supply chains. Here, we complement it by a classification of the risk from human water use, a comprehensive conceptualisation of water use and a spatially-explicit impact assessment to a midpoint approach that assesses the risk of on-site and remote freshwater scarcity. For a 2 MWh Lithium-ion battery storage, the quantitative Water Scarcity Footprint, comprising physically used water, accounts for 33,155 regionally weighted m3 with highest contributions from Chilean lithium mining. The qualitative Water Scarcity Footprint, the virtual volume required to dilute pollutant emissions to safe concentrations, is approximately determined to 52 million m3 of regionally weighted demineralised water with highest contributions from copper and aluminium mining operations. As mining operations seem to have the highest impact, we recommend to consider the spatially-explicit water scarcity footprint for assessment of global material supply.

Life Cycle Environmental Impacts and Energy Demand of Craft Mezcal in Mexico

Agave distillates, such as tequila and mezcal, are alcoholic spirits representative of Mexican culture. In recent years, the demand for mezcal has increased, and with it the requirement for raw materials, bringing with it a series of difficulties. The objective of this study was to evaluate the potential environmental impact and energy demand of the production of young craft mezcal from an endemic agave (Agave cupreata) found in the central and southern Pacific area of Mexico. The potential environmental impact of the mezcal studied was obtained through the life cycle analysis methodology using a midpoint approach by the ReCiPe method to calculate the potential environmental impact with SimaPro software (version 8.2.3.0., PRé Sustainability, Amersfoort, The Netherlands). The functional unit is a young craft mezcal bottle of 750 mL with 46% Vol. Alc. The stage of highest contribution to the environmental impact of mezcal was the manufacturing/processing, contributing 59.6% of them. The energy demand of the craft mezcal resulted in 163.8 MJ/bottle of 7.5 dl. The kg CO2eq in mezcal (1.7) is higher than beer (0.63) or white wine (1.01), but lower than whisky (2.25) or pisco (3.62). These findings could allow the search for alternatives for the development of sustainable production.

Environmental Sustainability of Heating Systems Based on Pellets Produced in Mobile and Stationary Plants from Vineyard Pruning Residues

The impact of heat production from vineyard pruning pellets has been evaluated in this paper. The study considers two different systems: the first one based on a mobile pelletizer (PS1) and the second one based on a stationary pellet plant (PS2). The analysis conducted is from “cradle to grave”; the systems under analysis includes pruning harvesting, transport to storage area, pelletization (mobile system or stationary production plant), transport to consumer and combustion. The functional unit selected is 1 MJ of thermal energy produced. The impact assessment calculation methods selected are Eco-Indicator 99 (H) LCA Food V2.103/Europe EI 99 H/A with a midpoint and endpoint approach, and ReCiPe Midpoint (H) V1.10. Considering Life Cycle Assessment results, Eco-indicator shows a total impact of 4.25 and 4.07 mPt for mobile pelletizer and stationary pellet plant, respectively. Considering the three damage categories, PS1 has values of 2.4% (Human Health), 3.8% (Ecosystem Quality) and 17.3% (Resources), more impactful than PS2. Contribution analysis shows that direct emissions are the major damage contributor, followed by wood ash management. From a comparison between the baseline scenario and a scenario with an avoided product (wood ash as a standard potassium fertilizer), PS1 and PS2 with an avoided product approach are 41% and 40% less impactful than in the baseline scenarios. When testing the impact of mobile pelletizer while considering transportation as a factor, a reduction of distance for pellet has been evaluated. Reducing the distance from 100 to 10 km, the total impact of PS1 almost reaches the impact of PS2 with a difference of around 4.6% (Eco-indicator 99 method). The most impactful processes are pellet production, direct emissions and ash management, while a less impactful factor is the electricity consumption. Transportation shows the lowest impact. Considering the ReCiPe impact calculation method with a midpoint approach, the results confirm what was found with Eco-indicator 99; the PS1 shows a slightly higher impact than PS2.

Environmental performance scenarios in the production of hollow glass containers for food packaging: an LCA approach

PurposeThe importance of glass in the production of food packaging has stimulated the assessment of its impact. This study evaluates the environmental performance of hollow glass production in a manufacturing plant operating in Apulia (Italy), compares baseline and two alternative scenarios based on the life cycle assessment (LCA) method and proposes more environmentally friendly options.MethodsThe LCA study was performed on primary data provided by a company for 2017 and secondary data retrieved from databases. The LCA was conducted according to ISO 14040:2006 and 14044:2018 with product category rule (PCR) basic module CPC 37. A midpoint approach was chosen. The software selected for the analysis was GaBi thinkstep AG version 8.7.0.18. The study was performed from cradle to grave, and the functional unit considered was 1 kg of finished hollow glass.Results and discussionA comparative analysis of the different scenarios was conducted considering seven environmental impact indicators. The results highlight major improvements in the environmental impact indicators: in particular, the replacement of raw materials with cullets would yield significant improvements if all of the cullets are recovered in the regional territory. These improvements, as confirmed by the results of Scenario 2, could be further increased both by the use of renewable energy such as photovoltaic (PV) energy and by technological improvements such as lightweighting.ConclusionsThrough the LCA, the authors quantified the potential environmental impact associated with the production of hollow glass, thereby identifying solutions and formulating suggestions to reduce the environmental impacts associated with food packaging. The evaluation of the different scenarios could help managers in the decision-making process, thus improving the environmental performance of both the process and final product.

Cradle-to-Gate Water-Related Impacts on Production of Traditional Food Products in Malaysia

Modern technology and life-style advancements have increased the demand for clean water. Based on this trend it is expected that our water resources will be under stress leading to a high probability of scarcity. This study aims to evaluate the environmental impacts of selected traditional food manufacturing products namely: tempe, lemang, noodle laksam, fish crackers and salted fish in Malaysia. The cradle-to-gate approach on water footprint assessment (WFA) of these selected traditional food products was carried out using Water Footprint Network (WFN) and Life Cycle Assessment (LCA). Freshwater eutrophication (FEP), marine eutrophication (MEP), freshwater ecotoxicity (FETP), marine ecotoxicity (METP) and water consumption (WCP), LCA were investigated using ReCiPe 2016 methodology. Water footprint accounting of blue water footprint (WFblue), green water footprint (WFgreen) and grey water footprint (WFgrey) were established in this study. It was found that total water footprint for lemang production was highest at 3862.13 m3/ton. The lowest total water footprint was found to be fish cracker production at 135.88 m3/ton. Blue water scarcity (WSblue) and water pollution level (WPL) of these selected food products were also determined to identify the environmental hotspots. Results in this study showed that the WSblue and WPL of these selected food products did not exceed 1%, which is considered sustainable. Based on midpoint approach adopted in this study, the characterization factors for FEP, MEP, FETP, METP and WCP on these selected food products were evaluated. It is recommended that alternative ingredients or product processes be designed in order to produce more sustainable lemang.

Environmental Impact Studied using Life Cycle Assessment on Cement Industry

The rapid development in Indonesia has caused cement production to be directly proportional to its needs. The cement industry produces commercial cement for domestic development needs. Cement is made by means of a series of exploitation and production processes that involve the main process and supporting processes in its activities. To be able to produce cement, it requires raw materials, fuel and chemical additives, and these activities produce emissions that have an impact of decreasing environmental quality. The gas emissions produced are CO2, CH4, NOx, SOx, N2O and particulate. These emissions have an impact of increasing global warming and decreasing ambient air quality which has an impact on human health and the environment. This study identifies the impact of the main process based on the cradle-to-gate approach, starting from the process of exploitation of raw materials to the production process that produces cement as the main product. Impact identification was done using the Life Cycle Assessment (LCA) method with the SimaPro 8.5.2 application. The Life Cycle Impact Assessment (LCIA) categories include global warming potential for 100 years, acidification, and carcinogens. The method used was TRACI, a midpoint approach. Results after normalization show that the highest impacts generated were global warming from kiln process (353,473); acidification from kiln process (95,273), and carcinogens from raw mill process (4,837,721).

Influence of Cannulation Point on Infraclavicular Subclavian Vein Catheterization: A Clinical Trial.

BackgroundChoosing a proper approach to subclavian vein cannulation is a challenge for physicians. However, percutaneous infraclavicular subclavian vein cannulation is now an acceptable technique.ObjectivesThe present study was performed to compare the success rate and complications of subclavian vein cannulation using the midpoint technique and the lateral technique.MethodsIn this prospective randomized clinical trial, we randomly assigned 440 patients undergoing subclavian vein cannulation to either midpoint approach or lateral approach groups from April 2018 to February 2019. The complications and success rates of catheterization were compared between the two approaches. The data were analyzed using SPSS software (version 20).ResultsUnlike the first attempt of catheterization, the success rate was significantly higher in the midpoint technique (75 %) than in lateral technique (39%) in the second attempt (P = 0.003). The overall success rates were 96.8% and 88.6% in the midpoint approach and lateral approach, respectively. A significant difference was observed between the two techniques in the overall success rate (P = 0.001). Inadvertent subclavian artery puncture occurred in 26 (5.9%) patients including 3 (1.4%) patients in the midpoint technique and 23 (10.5%) patients in the lateral technique. In 19 (4.3%) patients, malposition of the catheter tip occurred, including 14 (6.4%) in the midpoint approach and 5 (2.3%) in the lateral approach. There was a significant difference between the two approaches in malposition and subclavian artery puncture (P = 0.035 and P = 0.0001, respectively). There were no significant differences between the two techniques in other complications.ConclusionsThis investigation showed that the midpoint approach was more appropriate than the lateral approach for infraclavicular subclavian vein catheterization with landmark-based techniques.

Estimating the Age at HIV Infection Retroactively in Limited Resource Settings: <i>A Case Study of Tanzania</i>

Estimation of HIV infection time is a crucial step in HIV/AIDS management as it can help to make informed decisions on the best intervention strategies for controlling new infections, and for taking care of the infected individuals. This study demonstrates three approaches for estimating the age at HIV infection in limited resource settings. Using HIV testing history data collected from a sample of 88 HIV positive women in Kilimanjaro region-Tanzania, we developed a model for estimating the most likely age at which HIV infection occurs for women under reproductive age. The sampled data were collected from typical poor resource settings where access to data is very challenging and the gap between last HIV negative test and first HIV positive test is wide. Formulation of the proposed model involved three steps. Through Modified Midpoint approach, we first determined the midpoint of the age at last negative HIV test and the age at first positive HIV test for each subject. Then, the average time at risk prior to infection, taken over all individuals was subtracted from each midpoint value to obtain the distribution of their estimated age at HIV infection (T). In the second step, survival analysis techniques were used to obtain the Kaplan Meier plots and Nelson Aalen cumulative hazards estimates in which the median age for HIV infection and the most risky age were estimated. The plots of Kaplan Meir survival curves for women with different marital status and levels of education helped to assess whether their age at infection were significantly different. In the third step, we used bootstrap estimation procedures to generate 200 samples of random data and obtain the bootstrap median age at HIV infection and its confidence intervals. The estimated median age at HIV infection from survival analysis approach was 28 years while from bootstrap estimation procedures was 27 years. Likewise, the Nelson Aalen cumulative hazards plot indicated that the most risky age for HIV infection is between 18-40 years while the most risky age from bootstrap estimation was 25 to 27 years. The confidence intervals obtained through bootstrap estimation approach was narrower than that obtained from the survival analysis approach, implying that the bootstrap approach gives more precise estimates. Generally, the study findings provide useful information towards the attainment of the 90-90-90 global HIV/AIDS target as it shows where to allocate more resources and establish more focused interventions for HIV/AIDS management and control.

Representative scenario construction and preprocessing for robust combinatorial optimization problems

In robust combinatorial optimization with discrete uncertainty, approximation algorithms based on constructing a single scenario representing the whole uncertainty set are frequently used. One is the midpoint method, which uses the average case scenario. It is known to be an N-approximation, where N is the number of scenarios. In this paper, we present a linear program to construct a representative scenario for the uncertainty set, which gives an approximation guarantee that is at least as good as for previous methods. We further employ hyper heuristic techniques operating over a space of preprocessing and aggregation steps to evolve algorithms that construct alternative representative single scenarios for the uncertainty set. In numerical experiments on the selection problem we demonstrate that our approaches can improve the approximation guarantee of the midpoint approach by more than 20%.

Evaluation of the feasibility of Common Mid-Point approach for air-coupled GPR applied to road pavement assessment

Ground Penetrating Radar (GPR) is commonly used in pavement assessment, manly for measuring pavement layer thickness. Asphalt layer thickness is the most relevant input for flexible pavements assessment. The present study evaluates the feasibility of the Common Mid-Point (CMP) method, for a coreless GPR approach, using air-coupled antennas. Three test sections, with different asphalt layer thicknesses, were evaluated using a pair of 1.8 GHz air-coupled antennas. Results highlight the satisfactory performance of the CMP method with air-coupled antennas. The estimation of the asphalt layer thickness leads to a linear coefficient of determination greater than 0.95 when compared with the measured thickness from cores. The CMP method presented lower average absolute errors for the thinner asphalt layers (about 6 cm) in comparison with the SRM method (6% vs 18%). For thicker layers (from 11 to 13 cm), the average absolute errors for both methods were similar (approximately 7%).

An integrated environment and cost assessment method based on LCA and LCC for mechanical product manufacturing

The purpose of this study is to provide an integrated method to identify the resource consumption, environmental emission, and economic cost for mechanical product manufacturing from economic and ecological dimensions and ultimately to provide theoretical and data support of energy conservation and emission reduction for mechanical product manufacturing. The applied research methods include environmental life cycle assessment (LCA) and life cycle cost (LCC). In life cycle environmental assessment, the inventory data are referred from Chinese Life Cycle Database and midpoint approach and EDIP2003 and CML2001 models of life cycle impact assessment (LCIA) are selected. In life cycle cost assessment, three cost categories are considered. The proposed environment and cost assessment method is based on the theory of social willingness to pay for potential environmental impacts. With the WD615 Steyr engine as a case, life cycle environment and cost are analyzed and evaluated. The case study indicates that, in different life cycle phases, the trend of cost result is generally similar to the environmental impacts; the largest proportion of cost and environmental impact happened in the two phases of “material production” and “component manufacturing” and the smallest proportion in “material transport” and “product assembly.” The environmental impact category of Chinese resource depletion potential (CRDP) accounted for the largest proportion, followed by global warming potential (GWP) and photochemical ozone creation potential (POCP), whereas the impacts of eutrophication potential (EP) and acidification potential (AP) are the smallest. The life cycle “conventional cost” accounted for almost all the highest percentage in each phase (except “material transport” phase), which is more than 80% of the total cost. The “environmental cost” and “possible cost” in each phase are relatively close, and the proportion of which is far below the “conventional cost.” The proposed method enhanced the conventional LCA. The case results indicate that, in a life cycle framework, the environment and cost analysis results could support each other, and focusing on the environment and cost analysis for mechanical product manufacturing will contribute to a more comprehensive eco-efficiency assessment. Further research on the life cycle can be extended to phases of “early design,” “product use,” and “final disposal.” Other LCIA models and endpoint indicators are advocated for this environmental assessment. Environmental cost can also be further investigated, and the relevant social willingness to pay for more environmental emissions is advocated to be increased.

Trends in Phenological Parameters and Relationship Between Land Surface Phenology and Climate Data in the Hyrcanian Forests of Iran

Vegetation activity may be changed in response to climate variability by affecting seasonality and phenological events. Monitoring of land surface phenological changes play a key role in understanding feedback of ecosystem dynamics. This study focuses on the analysis of trends in land surface phenology derived parameters using normalized difference vegetation index time series based on Global Inventory Monitoring and Mapping Studies data in the Hyrcanian forests of Iran covering the period 1981–2012. First, we applied interpolation for data reconstruction in order to remove outliers and cloud contamination in time series. Phenological parameters were retrieved by using the midpoint approach, whereas trends were estimated using the Theil–Sen approach. Correlation coefficients were evaluated from multiple linear regression between phenological parameters against temperature and precipitation time series. Significant Mann–Kendall test analysis indicate average start of season (SOS) and end of season (EOS) increased by −0.16 and +0.14 days per year, respectively. Results of significant trend analysis showed that later EOS was associated with increasing temperature trends and we found strongest relationships between temperature and phenological parameters in the west of the Hyrcanian forests, where precipitation was abundant. Moreover, SOS correlated strongly with total precipitation and mean temperature. This study allows us to better estimate the drivers affecting the vegetation dynamics in the Hyrcanian forests of Iran.

Life-Cycle Assessment: A Comparison between Two Optimal Post-Tensioned Concrete Box-Girder Road Bridges

The goal of sustainability involves a consensus among economic, environmental and social factors. Due to climate change, environmental concerns have increased in society. The construction sector is among the most active high environmental impact sectors. This paper proposes new features to consider a more detailed life-cycle assessment (LCA) of reinforced or pre-stressed concrete structures. Besides, this study carries out a comparison between two optimal post-tensioned concrete box-girder road bridges with different maintenance scenarios. ReCiPe method is used to carry out the life-cycle assessment. The midpoint approach shows a complete environmental profile with 18 impact categories. In practice, all the impact categories make their highest contribution in the manufacturing and use and maintenance stages. Afterwards, these two stages are analyzed to identify the process which makes the greatest contribution. In addition, the contribution of CO2 fixation is taken into account, reducing the environmental impact in the use and maintenance and end of life stages. The endpoint approach shows more interpretable results, enabling an easier comparison between different stages and solutions. The results show the importance of considering the whole life-cycle, since a better design reduces the global environmental impact despite a higher environmental impact in the manufacturing stage.

Estimation of Market Information Shares: A Comparison

AbstractThis note investigates via Monte Carlo simulation the finite‐sample performance of two identification schemes that provide unique measures of Hasbrouck‐type information share in price discovery. The Lien and Shrestha (2009) method is based on factorization of the full correlation matrix and the Grammig and Peter (2013) method is based on different correlations of price innovations in the tails and in the center of the distributions. We find that the GP method performs poorly under the chosen data generation processes. The LS method provides at most marginal improvement over the method based upon the upper/lower bound midpoint of the Hasbrouck measure. The results, therefore, support the common practice of the midpoint approach. © 2016 Wiley Periodicals, Inc. Jrl Fut Mark 36:1108–1124, 2016

Modeling Recreation Demand When the Access Point Is Unknown

Not observing where an individual enters a geographically large recreation area complicates the task of modeling recreation demand. Traditionally, analysts have arbitrarily defined distances on the basis of the midpoint of a river or beach segment or on the basis of the nearest access point. In this article, we draw on the aggregation literature to generate a consistent framework for incorporating information on site characteristics and travel costs gathered at a finer level than that used to obtain trip counts. We use Monte Carlo experiments to illustrate the performance of the traditional midpoint and nearest access point approximations. Our results suggest that, while the nearest access point approach often provides a good approximation to underlying preferences, use of the midpoint approach can lead to significant bias in the travel cost parameter and corresponding welfare calculations. Finally, we use our approach to model recreation demand for the major river systems in Iowa using data from the 2009 Iowa Rivers and River Corridors Survey.

Ankle fusion with a retrograde locked intramedullary nail for sequela of lower extremity compartment syndrome

ObjectiveTo assess the value of ankle fusion with a retrograde locked intramedullary nail in the treatment of sequela of lower extremity compartment syndrome. MethodsThirty-five cases of equinus deformity following tibiofibular compartment syndrome treated by means of ankle fusion with a retrograde locked intramedullary nail from January 2001 to December 2010 were retrospectively reviewed. The complications, the time needed for bony fusion of the ankle joint assessed by anteroposterior and lateral X-ray photographs as well as patients’ subjective evaluation were recorded and analysed. ResultsAmong the 35 patients, 15 had previously undergone surgical treatment twice on the same limb, 13 had thrice and 7 had to be operated on four times before ankle fusion. An anterior midpoint approach to the ankle joint was adopted in 29 cases, while anterior midpoint approach plus a small incision on the posterior ankle joint was made in 17 cases, whereas lateral approach in 6 cases. Tarsus joint fusion was performed on 4 cases. The follow-up period ranged 6-124 months, averaged 40.6 months. Bone grafting was not performed in this series. Preoperative tibial shaft fracture occurred in one patient and was healed after conservative treatment. Incision dehiscence located at previous Achilles tendon incision was found in two patients. As a result, one received an intramedullary nail emplacement at calcaneoplantar part while the wound at anterosuperior part of the other one was healed by dressing change. Two patients failed to bony union 5 months postoperatively, in which one healed 10 weeks after retrieval of proximal tibial nail and another by iliac grafting. Terminal necrosis of the toe due to blood supply dysfunction was not found in this series. All the patients were satisfied with the ankle joint function postoperatively. The time for bony union on X-rays was 9.8 weeks on average. Except for one patient who demanded removal of intramedullary nail, all the intramedullary nails were not retrieved at the end of follow-up. Nail breakage happened in one patient and no other breakage or backing out of the nail was found. ConclusionsLower extremity compartment syndrome and residual ankle deformity often extremely impact ambulation and are hard to deal with because several pathologic phenomena might exist in these patients, for instance, poor skin conditions due to repeated preexisting surgery; poor perfusion in distal limbs following blood vascular injury; reflux limitation and long-term limb swelling due to muscle strength disturbance; osteoporosis as a result of long-term immobilization or limb disuse. Ankle fusion with a retrograde locked intramedullary nail is an optimal protocol to solve these clinical symptoms and rather ensures a definite fusion and firm fixation to these patients with simple manipulation and few complications.

Carbon footprint of a thermal energy storage system using phase change materials for industrial energy recovery to reduce the fossil fuel consumption

Until now, a small number of studies have analysed the carbon footprint (CO2 eq. emissions) of the application of Phase Change Materials (PCMs) in conventional Thermal Energy Storage (TES) systems considering different conventional fossil fuels as the source of heat. In those scarce studies, the different environmental impact categories were estimated using, on the one hand, diverse environmental methodologies and, on the other hand, different environmental evaluation methods (the midpoint and endpoint approaches). Despite the fact that several researchers have used the Life Cycle Assessment (LCA) methodology as a tool to estimate the environmental impact of TES systems, there is no unanimity in the scientific community on the environmental evaluation method to be used. As a consequence, research results cannot be easily compared. This article evaluates the introduction of a TES system (using different PCMs) to recover the waste thermal energy released in industrial processes, which can be used in other applications, thereby avoiding fossil fuel consumption by the associated equipment to produce thermal energy. Five different fossil fuels have been considered to generate the 20 case studies that were analysed using the same methodology (LCA) and evaluation method (Global Warming Potential, GWP100, a midpoint approach). The results were used to identify the best cases, considering the environmental benefits that they generate. Additionally, this research indicates that the benefits can be achieved since, in general, the amount of conventional fuels saved is sufficiently large to balance the environmental impact associated with the inclusion of PCMs in conventional TES. Nevertheless, the selection of a PCM can increase or eliminate the environmental benefits obtained.

Application of LCA by Using Midpoint and Endpoint Interpretations for Urban Solid Waste Management

Life cycle assessment (LCA) is one of the most widely used methods of decision support. However, few studies have examined whether stakeholders prefer midpoint or endpoint approaches. In this regard, the present study examines the attitudes toward urban solid waste management, environmental issues, and scenario evaluations by using midpoint and endpoint interpretations of LCA results. This study introduces three types of social groups that typically respond to environmental conflicts: the individualist, hierarchist, and egalitarian groups. Although residents are likely to recognize global impacts as the most important issue, their view is likely to change depending on system and avoided emissions. Consistent with the Seoul Metropolitan Area’s new policy designed to increase the incineration ratio, almost half of all respondents preferred the scenario. Noteworthy is that the respondents’ preference for midpoint and endpoint decision-making tools is not consistent with that in previous studies. Most of the respondents indicated that the midpoint approach would be better in evaluating environmental systems.

An Efficient Scan Conversion of Parabola on Hexagonal Grid

In this paper the midpoint approach for efficient scan conversion of parabola on hexagonal grid is proposed. The mid-point approach computes pixel nearest true curve using only integer arithmetic. The proposed algorithm is compared favorably with the existing parabola drawing algorithm on square grid. Owing to this approach we may visualize design ideas through animations and photorealistic renderings, and simulate how a design will perform in the real world in CAD tool with less aliasing artifact.

Stability of Implicit Midpoint Algorithm Applied to Structures with Nonlinear Damping

Stability of implicit midpoint algorithm applied to solving the equation of motion with nonlinear damping. The analytical and numerical study exhibit the unconditional stability of implicit midpoint scheme for nonlinear damping systems. The work of the present paper provides theoretic base for further application of this implicit midpoint approach.