Economic Costs Research Articles

Recent Progress in Situ Application of H2O2 Produced via Catalytic Synthesis.

Industrial production of H2O2 requires lots of energy and causes environmental pollution. Moreover, in subsequent applications, much economic loss could be produced during the transportation process of H2O2 and its dilution process. Therefore, it is highly desirable for in situ application of H2O2. In recent years, catalytic synthesis of H2O2, e. g., direct catalytic synthesis, electrocatalytic synthesis, and photocatalytic synthesis, has attracted more and more attention because the continuous and low-concentration H2O2 produced by catalytic synthesis can be directly used for the oxidation of organic compounds, effectively avoiding the shortcomings of the current industrial route. Here, we briefly reviewed the latest processes for the catalytic production of H2O2 via various routes. On this basis, we summarized and discussed the in situ application of H2O2 in typical organic conversion reactions, including the ammoximation of ketones, the oxidation of alcohols, the oxidation of C-H bonds, and the oxidation of olefins. Some in situ coupling reactions have shown excellent performance with high conversion and selectivity, and the economic cost has been significantly reduced. Finally, the shortcomings of the in situ utilization of H2O2 in coupling reactions were analyzed, and some strategies for promoting the efficiency of the H2O2 application in organic synthesis were proposed.

Venous disease progression in western Europe (VENPRO): A prospective cohort study.

Objective: A prospective cohort study aimed to determine factors which influence the progression of chronic venous disease (CVD) in an attempt to aid in the early identification of those at patients who are likely to benefit from early intervention.Methods: A prospective cohort study of patients referred to tertiary vascular services with varicose veins over 7years was conducted. The primary outcome measure was the rate of disease progression from time of referral to time of consultation. The secondary outcome measure was to the rate of venous complications during the same time period.Results: 1000 patients from routine varicose vein waiting lists were included in the study. The mean waiting time was 2.96 ± 1.25years. The majority of patients were female (73% versus 27%), and the average age was 57.8 ± 14.7years. One fifth of the cohort developed a complication or showed evidence of disease progression. Logistic regression showed that advancing age and previous episodes of cellulitis are significant risk factors for the development of CVD progression.Conclusions: Varicose veins are more than a cosmetic issue and can be associated with substantial health and economic costs. Continuous identification of risk factors will enable clinicians to implement treatment strategies earlier for at risk patients.

Study on the analytical verification method of geometric error models

Abstract Geometric error compensation is a widely used and effective approach for enhancing the accuracy of Coordinate Measuring Machines (CMMs) and Computer Numerical Control (CNC) machines. The research in this field primarily focuses on the challenging task of developing geometric error modelling techniques. Currently, there are several well-established methods for modelling geometric errors. However, there is scarce availability of methods that can validate the established geometric error models. Therefore, this article proposes an analytical validation method for geometric error models based on the error transformation equation. The principle of the method is elaborately explained, and its correctness is verified through specific model verification example. The method proposed in this article enables rapid and accurate model correction and iteration, effectively reducing the economic and time costs of model validation in the current geometric error compensation process. Therefore, the method provides guidance for standardising the modelling process and could be widely applied to various structural forms of measurement and machining systems.

Experimental analysis of a solar air heater using waste mild steel chips as a sensible heat storage material.

Heat storage materials improve the utility of solar air heaters (SAHs) after sunset. This study investigates an improved solar air heater (SAH) performance with baffles and waste mild steel chips as sensible heat storage (SHS) materials. Comparative experimental natural convection heat transfer studies were performed with four different improved air heater setups under similar solar radiation conditions. These setups consist of a flat collector plate (I), a baffled plate collector (II), a flat plate collector with SHS (III) and a baffled plate collector with SHS (IV) respectively. Setups I, II, III and IV were obtained by modifying the same air heater enclosure and each experiment was replicated for three similar sunny days. During the periods, the solar radiation varied in the range of 556-934 W/m2. The maximum thermal efficiencies found for setups I, II, III and IV were 18.76%, 22.40%, 27.21% and 28.22% respectively under natural convection. The highest average useful energy rate was produced by setup IV, followed by setups III, II and I. After sunset, setups III and IV were able to deliver warm air for an extended period of 1h, 18min and 1h, 42min, respectively. It was found that setups III and IV had sensible thermal energy storage reserves of 0.38kJ and 0.53kJ, respectively. The storage efficiencies found for setups III and IV were 60.25% and 70.89%, respectively. Among the four setups, setup IV boasts the most economical energy cost at 1.39 ₹/kWh and having the least payback period of 1year 4months. As a result, the employment of baffles and waste mild steel chips as SHS in a flat plate SAH not only presents a method for harvesting waste for efficient heat retention, but it also effectively uses solar energy for beneficial uses.

An Update on Emerging Regenerative Medicine Applications: The Use of Extracellular Vesicles and Exosomes for the Management of Chronic Pain.

Chronic pain affects nearly two billion people worldwide, surpassing heart disease, diabetes, and cancer in terms of economic costs. Lower back pain alone is the leading cause of years lived with disability worldwide. Despite limited treatment options, regenerative medicine, particularly extracellular vesicles (EVs) and exosomes, holds early promise for patients who have exhausted other treatment options. EVs, including exosomes, are nano-sized structures released by cells, facilitating cellular communication through bioactive molecule transfer, and offering potential regenerative properties to damaged tissues. Here, we review the potential of EVs and exosomes for the management of chronic pain. In osteoarthritis, various exosomes, such as those derived from synovial mesenchymal stem cells, human placental cells, dental pulp stem cells, and bone marrow-derived mesenchymal stem cells (MSCs), demonstrate the ability to reduce inflammation, promote tissue repair, and alleviate pain in animal models. In intervertebral disc disease, Wharton's jelly MSC-derived EVs enhance cell viability and reduce inflammation. In addition, various forms of exosomes have been shown to reduce signs of inflammation in neurons and alleviate pain in neuropathic conditions in animal models. Although clinical applications of EVs and exosomes are still in the early clinical stages, they offer immense potential in the future management of chronic pain conditions. Clinical trials are ongoing to explore their therapeutic potential further, and with more research the potential applicability of EVs and exosomes will be fully understood.

Comprehensive Management of Water Resources: A Step-By-Step Path Towards a Sustainable Campus At The U.D.C.A (Bogotá, Colombia)

Universities are recognized as essential agent of change since future decision-makers related to sustainability are going and will pass through their classrooms. This circumstance becomes an excellent opportunity to demonstrate, with example, and instill in the students how these types of organizations control and approach implementing practices that guarantee sustainability and the appropriate use of resources over time. The Universidad de Ciencias Aplicadas y Ambientales has undertaken different actions related to the Integrated Water Resources Management (IWRM) on campus since 1990. This work focuses on the actions carried out by the Integrated Environmental Management System (latest institutional management model) between the 2014-2016 period to improve the university campus's IWRM (drinking water and wastewater management) from a systemic point of view. The actions implemented were part of the project: Reusing treated water at the University's Wastewater Treatment Plant (WWTP). This project included the following objectives: 1) Reduce the volume and economic costs of sludge water disposal; 2) Reduce drinking water consumption; and 3) Promote environmental education about water resources in students of the different programs of the University. The results were: 1) A decrease of 68.3% in volume and 69.5% in costs of sludge water disposal; 2) A 41.2% saving in drinking water consumption; and 3) 2,475 members of the university community impacted by issues related to the management of water resources.

The economic burden of long COVID in Australia: more noise than signal?

To estimate the potential economic burden of long COVID in Australia. A stock-and-flow model of weekly estimated numbers of people with long COVID (January 2021 to June 2023); application of proxy cost estimates from people living with myalgic encephalomyelitis/chronic fatigue syndrome; time series analysis of labour market and social security datasets. The working age Australian population. The likely number of Australians severely impacted by long COVID; the economic cost of long COVID; and the impacts of long COVID, determined by analysis of labour market data. At its peak in late 2022, between 181 000 and 682 000 Australians may have experienced some long COVID symptoms, of whom 40 000-145 000 may have been severely affected. Severe cases potentially decreased to affecting 10 000-38 000 people by June 2023. The likely economic burden of long COVID in Australia during 2022 was between $1.7 billion and $6.3 billion (some 0.07% to 0.26% of gross domestic product). Labour market data suggest that between 25 000 (February 2023) and 103 000 (June 2023) more working age Australians reported being unable to work due to long term sickness than would have been predicted based on pre-COVID-19 trends. This does not appear to have translated into increased claims for Disability Support Pensions, but numbers of working age Carer Allowance recipients have grown markedly since 2022. Long COVID likely imposed a small but significant aggregate toll on the Australian economy, while exposing tens of thousands of Australians to substantial personal economic hardship and contributing to labour market supply constraints. Yet while some signal from long COVID is discernible in the labour force data, Australia lacks adequate direct surveillance data to securely guide policy making.

Controlled Stimulus-Responsive Delivery Systems for Osteoarthritis Treatment

Osteoarthritis (OA), a common and disabling degenerative joint disease, affects millions of people worldwide and imposes a considerable burden on patients and society due to its high prevalence and economic costs. The pathogenesis of OA is closely related to the progressive degradation of articular cartilage and the accompany inflammation; however, articular cartilage itself cannot heal and modulate the inflammation due to the lack of nerves, blood vessels, and lymph-vessels. Therefore, reliable and effective methods to treat OA remain highly desired. Local administration of drugs or bioactive materials by intra-articular injection of the delivery system represents a promising approach to treat OA, especially considering the prolonged joint retention, cartilage or chondrocytes targeting, and stimuli-responsive release to achieve precision OA therapy. This article summarizes and discusses the advances in the currently used delivery systems (nanoparticle, hydrogel, liposome, and microsphere) and then focuses on their applications in OA treatment from the perspective of endogenous stimulus (redox reactions, pH, enzymes, and temperature) and exogenous stimulus (near-infrared, magnetic, and ultrasound)-responsive release. Finally, the challenges and potential future directions for the development of nano-delivery systems are summarized.

Cost of integrated immunization campaigns in Nigeria and Sierra Leone: bottom-up costing studies

BackgroundTo improve the efficient use of scarce resources, low- and middle-income countries and development partners are increasingly encouraged to deliver multiple vaccines and other interventions in a single integrated campaign. However, little is known regarding the cost of delivering vaccines through integrated campaigns, and the extent to which efficiencies are achieved. To fill this evidence gap, we estimated the cost of integrated immunization campaigns in Nigeria and Sierra Leone, and the potential savings from integration.MethodsWe conducted a retrospective ingredients-based costing study from a payer perspective of a campaign held in 2019 in Sierra Leone with measles-rubella vaccine and oral polio vaccine, during which nutrition supplements were also offered in part of the country, and yellow fever campaigns held in three states in Nigeria in 2019 and 2020, where in one state (Anambra) meningococcal A vaccines were co-delivered. We collected data from 108 health facilities, all relevant administrative levels, and implementing partners. We estimated the full financial and economic cost of each campaign, the average unit cost of delivery, as well as the cost by activity and resource type. We also estimated the cost savings from integration in Anambra state by modelling out the cost of the alternative of two standalone campaigns.ResultsThe average financial delivery cost was $0.34 per dose in Sierra Leone, and the economic cost was $0.73 per dose. In Nigeria, the financial cost per dose was $0.29–$0.35 across the three states, and the economic cost per dose was $0.62–$0.85. Facilities and wards delivering more doses achieved a lower financial and economic unit cost of delivery, demonstrating evidence of economies of scale. We estimated that Anambra may have saved at least $1,204,133 in financial resources by integrating yellow fever and meningitis A vaccine delivery, amounting to $0.17 per dose delivered. When including opportunity costs, the economic cost saving was estimated at $0.34 per dose delivered.ConclusionsThe study offers evidence on what it costs to deliver integrated campaigns, and shows that integrated delivery is likely to result in significant cost savings. Where high delivery volumes can be achieved, integrated campaigns can benefit from economies of scale. The findings can be used to inform planning and budgeting for immunization campaigns in low- and middle-income countries.

Unlocking the potential for microbiome-based therapeutics to address the sustainable development goal of good health and wellbeing.

Recent years have witnessed major advances and an ever-growing list of healthcare applications for microbiome-based therapeutics. However, these advances have disproportionately targeted diseases common in high-income countries (HICs). Within low- to middle-income countries (LMIC), opportunities for microbiome-based therapeutics include sexual health epidemics, maternal health, early life mortality, malnutrition, vaccine response and infectious diseases. In this review we detail the advances that have been achieved in microbiome-based therapeutics for these areas of healthcare and identify where further work is required. Current efforts to characterise microbiomes from LMICs will aid in targeting and optimisation of therapeutics and preventative strategies specifically suited to the unmet needs within these populations. Once achieved, opportunities from disease treatment and improved treatment efficacy through to disease prevention and vector control can be effectively addressed using probiotics and live biotherapeutics. Together these strategies have the potential to increase individual health, overcome logistical challenges and reduce overall medical, individual, societal and economic costs.

Comparative life cycle assessment of non-thermal plasma for the removal of pharmaceuticals from wastewater

Wastewater effluents are a continuous source of pharmaceuticals in water bodies, which pose a serious environmental threat to aquatic ecosystems. This work provides a comprehensive technical, environmental and cost assessments of different advanced quaternary treatments for wastewater effluents, with special focus on novel Non-Thermal Plasma technology. For this porpouse Non-Thermal Plasma, Sand Filtration + Ozonation, Ultrafiltration, Ultrafiltration + Nanofiltration and Ultrafiltration + Reverse Osmosis technologies were compared with UV disinfection-based technology. This work applies the Life Cycle Analysis tool for the impact environmental assessment using both ReciPE 2016(H) method and, for a more detailed analysis of the contribution of pharmaceuticals to freshwater ecotoxicity category of impact, the USETOX method, which was integrated with 7 new characterisation factors. The results obtained showed overall removal efficiency of pharmaceuticals always higher than 80%, with performances in descending order of Ultrafiltration + Reverse Osmosis > Sand Filtration + Ozonation > Ultrafiltration + Nanofiltration > Non-Thermal Plasma, being Sand Filtration + Ultraviolet disinfection and standalone Ultrafiltration comparatively not suitable for pharmaceuticals removal. Regarding the target pharmaceuticals proposed on the EU Directive 271/91 revision, the Non-Thermal Plasma perform better towards venlafaxine than Sand Filtration + Ozonation, and towards diclofenac and carbamazepine than Ultrafiltration + Nanofiltration. Ultrafiltration + Nanofiltration and Non-Thermal Plasma showed better environmental performance than Sand Filtration + Ozonation and Ultrafiltration + Reverse Osmosis in 7 out of 18 categories of impact (ReciPe method), with Ultrafiltration + Nanofiltration being more advantageous than Non-Thermal Plasma in human and ecotoxicity-related categories of impact, and Non-Thermal Plasma more advantageous in Global Warming, Fossil Resource Scarcity, and Fine Particulate Matter Formation. Regrading Freshwater Ecotoxicity (USEtox method), the quaternary treatment configuration and its energy demand affect the Freshwater final value of impact more than the presence of pharmaceuticals. Under the conditions tested, the Non-Thermal Plasma provided the lower OPEX (0.24 € m−3) than other tested technologies, showing an interesting compromise between pharmaceuticals removal efficiency, environmental impacts, and economic operational cost.

Innovative materials integrated with PCM for enhancing photovoltaic panel efficiency: An experimental investigation

The electrical power generated by a photovoltaic panel is crucial due to the high demand for electricity. Operating temperatures above the Standard Test Conditions (STC) negatively impact the output power, which is a significant drawback of this technology. Therefore, it is essential to keep the front and back surface temperatures of the photovoltaic panel as low as possible. Phase Change Material (PCM) is a good passive cooling method, but it has low thermal conductivity. This paper introduces a novel material to address this issue. Iron Filling Waste (IFW) is integrated with PCM to cool the photovoltaic panel. This investigation is presented experimentally with three modules. The highest surface temperature of the reference panel, 78 °C, is recorded for the uncooled module, while with PCM- IFW is 70.5 °C. The comparative analysis shows that the PV module cooled by PCM-IFW achieved an efficiency enhancement and power output increase of 39 % and 33 % respectively, compared to the reference panel without cooling. IFW-PCM achieves an average enhancement in efficiency and output power by 23 % and 11 %, respectively, compared with panels that use PCM only. Also, IFW enhances thermal conductivity without any additional economic cost for the cooling systems.

Environmental Protection for Bureaucratic Promotion: Water Quality Performance Review of Provincial Governors in China

We show including quantitative environmental targets for bureaucratic promotion incentivizes government officials to enforce environmental regulation but at significant economic costs. Taking advantage of the gradual expansion of China’s water quality performance review (WQPR) over time and space, we find that WQPR significantly reduced ambient concentrations of criteria pollutants, digestive cancer mortality, and GDP growth rate. WQPR’s effects are more pronounced along provincial borders, which are targeted by WQPR, and when provincial governors have more promotion potential. An important mechanism is investment in wastewater treatment facilities. There is evidence that WQPR passed the benefit-cost test, especially in rural areas.

An innovative process for clean ammonium-free vanadium precipitation and one-step preparation of vanadium dioxide based on hydrothermal enhancement of organic alcohols

As a transition metal oxide, VO2 has excellent optical and electrical properties and is widely used in many fields. The production of VO2 by the reduction of NH4VO3 and V2O5 will inevitably produce ammonia–nitrogen wastewater and NH3 emission during the production of NH4VO3 and V2O5, which will cause serious environmental pollution and will increase economic costs. The large-scale and low-cost synthesis of VO2 still faces great challenges. In this paper, VO2(B) was successfully prepared by a one-step hydrothermal method using NaVO3 as the vanadium source and CH3CH2OH as the reducing agent, and the optimal conditions for vanadium precipitation are as follows: vanadium concentration = 30 g/L, CH3CH2OH dosage = 20 % (percentage of solution volume), initial pH = 1, reaction temperature = 220 °C, reaction time = 12 h. The vanadium precipitation efficiency under the optimal conditions could reach 98.93 %, and the purity of VO2(B) could reach 98.59 %. The precipitation products were characterized by XRD, TG, FTIR, XPS, and SEM-EDS. The mechanism of VO2(B) preparation by ethanol reduction was proposed. This process is characterized by green, clean, and high efficiency. At the same time, the vanadium precipitation effect and vanadium precipitation products of various alcohols were studied to provide technical and theoretical support for the preparation of VO2(B).

A study on the scaled intelligent supply mode of biomass briquette fuel in China

In the backdrop of China's ‘Carbon peak, Carbon neutrality’ goal, to reduce the pollution caused by carbon emissions to the atmosphere, this study investigates the supply of biomass briquette fuel. The supply of biomass briquette fuel is generally divided into two stages: the first stage involves the collection, storage, and transportation of biomass straw to the biomass briquette production base; the second encompasses the processing of the biomass straw into briquette fuel at the production base, followed by its transportation to the biomass boiler heating center for utilization. In this paper, a mathematical model is developed based on carbon emission and economic cost. The model is then calculated with an optimized intelligent algorithm, and the results are subjected to sensitivity analysis. The results demonstrate that: (1) Compared to the pre-optimization phase, the optimized model increases profits by 26.31 % and reduces carbon emissions by 12.64 %. (2) The adaptive genetic algorithm shows significantly better convergence speed and accuracy compared to the traditional genetic algorithm, making it more suitable for intelligent calculations of biomass briquette fuel supply. (3) As the weight coefficient of carbon emissions increases, economic costs continue to decrease with increasing sensitivity, while carbon emissions continue to decrease with decreasing sensitivity. These results provide references for further optimizing the weight coefficients of economic costs and carbon emissions in the supply of briquette fuel. This study contributes to reducing carbon emissions and provide references for the rational and intelligent supply of biomass briquette fuel.

Damocles's Switchboard: Information Externalities and the Autocratic Logic of Internet Control

Abstract This paper advances a theory for the autocratic logic of internet control. Politically motivated internet control generates a positive externality for domestic data-intensive firms and a negative externality for domestic knowledge-intensive research entities. Exploiting a major internet control shock in 2014, I find that Chinese data-intensive firms gained 26 percent in revenue over other Chinese firms as the result of internet control. The same shock incurred a 10 percent decline in research quality from Chinese researchers, conditional on the knowledge intensity of their discipline. It also reduced the research quality from Chinese researchers relative to their US counterparts by 22 percent in all disciplines. Due to the positive data externality, internet control enacted to prevent domestic threats challenges the state's competing need for data sovereignty against foreign threats. Meanwhile, the state shields certain foreign knowledge-intensive actors from the negative knowledge externality to avoid the immediate economic costs they might otherwise impose. Qualitative evidence supports both implications, highlighting the centrality of short-term interests and foreign actors in autocratic decision making.

Low-carbon optimal dispatch of park integrated energy system considering coordinated ammonia production from multiple hydrogen energy

The utilization of ammonia energy has garnered considerable global attention as a viable approach to alleviate pressure on energy supply within park integrated energy systems (PIES) and enhance energy efficiency. However, the introduction of ammonia production requires the system to increase large amounts of hydrogen, diversifying the sources of hydrogen and challenging the coordinated operation of PIES. In this paper, the inertia characteristics of the gas and thermal energy delivery process are utilized to increase the flexibility of the PIES operation. A technological framework for coordinated ammonia production from multi-hydrogen energy in PIES under consideration of having inertia characteristics and a low-carbon operation strategy for ammonia-doped combustion in thermal generation is constructed. Limiting carbon emissions through a stepped carbon trading mechanism in this strategy. In addition, while addressing the ammonia-doped requirement for thermal generation combustion, and by flexibly setting the ammonia doping ratio of thermal generation combustion, the operation of PIES under different ammonia-doped ratios has been analyzed in detail. The results demonstrate that the proposed model enhances the utilization of renewable energy, leading to reduction in total economic costs by 4.52 % and total carbon emissions by 24.81 %. This makes the operation of PIES more economical, low-carbon, and flexible.

Global techno-economic analysis of MBR for hospital wastewater treatment.

This study comprehensively examines and characterizes global membrane bioreactor (MBR) practices for hospital wastewater treatment, focusing on development trends, technical performance (pollutant removal and carbon emissions), and economic costs, including both capital expenditures (CAPEX) for civil engineering and equipment procurement, and operational expenditures (OPEX) for electricity, membrane replacement, labor, and chemical costs, as well as system footprint. The results show that MBR has been widely used for hospital wastewater treatment for over two decades, with global applications and scales significantly increasing, especially after the COVID-19 pandemic. A notable shift in membrane types has occurred, with hollow fiber membranes dominating before 2010 and flat inorganic membranes gaining prominence after 2020. MBR not only effectively removes conventional pollutants but also greatly reduces pathogens, ARBs and ARGs before disinfection, thus alleviating the subsequent disinfection burden. In addition, MBR is a crucial step in the process of completely removing emerging contaminants (ECs) that pose significant environmental and health risks. The CAPEX of MBR has decreased at the technical level in recent years. MBR requires only 62 % and 21 % of footprint for conventional activated sludge (CAS) and biofilm-based processes, respectively. MBR's land-saving advantage offsets the CAPEX gap with CAS in high land-cost areas. From before 2010 to after 2020, membrane costs saw the largest reduction in OPEX, dropping by 71 %, while electricity consumption saw a 10.71 % reduction, now comparable to biofilm-based processes. Currently, MBR's OPEX (0.158 USD/m3) is only slightly higher than that of biological contact oxidation (0.138 USD/m3). MBR also minimizes sludge production, reducing both treatment costs and associated disposal risks. MBR exhibit minimal concerns of excessive carbon emissions, with a carbon emission intensity (1.11 kg CO2eq·m-3), only slightly higher than biofilm-based processes (0.92 kg CO2eq·m-3). This study demonstrates that MBR is the valuable and practical solution for hospital wastewater treatment, as well as a preferred choice for upgrading existing facilities.

The Costs and Cost-Effectiveness of a Two-Dose Oral Cholera Vaccination Campaign: A Case Study in a Refugee Camp Setting in Thailand

Oral cholera vaccination (OCV) campaigns are increasingly used to prevent cholera outbreaks; however, little is known about their cost-effectiveness in refugee camps. We conducted a cost-effectiveness analysis of a pre-emptive OCV campaign in the Maela refugee camp in Thailand, where outbreaks occurred with an annual incidence rate (IR) of up to 10.7 cases per 1000. Data were collected via health sector records and interviews and household interviews. In the base-case scenario comparing the OCV campaign with no campaign, we estimated the campaign effect on the cholera IR and case fatality rate (CFR: 0.09%) from a static cohort model and calculated incremental cost-effectiveness ratios for the outcomes of death, disability-adjusted life-years (DALYs), and cases averted. In sensitivity analyses, we varied the CFR and IR. The household economic cost of illness was USD 21, and the health sector economic cost of illness was USD 51 per case. The OCV campaign economic cost was USD 289,561, 42% attributable to vaccine costs and 58% to service delivery costs. In our base case, the incremental cost was USD 1.9 million per death averted, USD 1745 per case averted, and USD 69,892 per DALY averted. Sensitivity analyses that increased the CFR to 0.35% or the IR to 10.4 cases per 1000 resulted in a cost per DALY of USD 15,666. The low multi-year average CFR and incidence of the cholera outbreaks in the Maela camp were key factors associated with the high cost per DALY averted. However, the sensitivity analyses indicated higher cost-effectiveness in a setting with a higher CFR or cholera incidence, indicating when to consider campaign use to reduce the outbreak risk.

Effect of working fluid charging amount on system performance in an ocean thermal energy conversion system

In ocean thermal energy conversion (OTEC) systems, the initial working fluid charging amount is crucial as it relates to the system’s performance and economic cost. But currently, there is no clear standard for it, and as the working fluid circulating pump is the most direct and only means to regulate the working fluid flow, it is necessary to investigate the coupled effects of it and the working fluid charging amount on the system performance. To this issue, a corresponding experimental facility was established. The coupled effects were investigated by energy and exergy analysis under varying temperature difference. The results showed that varying working fluid charging amount changed the physical state of the working fluid, and the effect on the system varied under dissimilar temperature difference conditions. Compared to the standard charge (8 kg), 75 % of the standard charging amount diminished the system thermal efficiency by 17 % and exergy efficiency by 16 % at small temperature difference (20 °C), whereas a charging amount of more than 100 % resulted in improved thermal efficiency by 14 % and exergy efficiency by 13 %. At large temperature difference (28 °C), 75 %, 125 % and 150 % of the standard working fluid charging amount all improved system performance (thermal efficiency by maximum 16 %, exergy efficiency by maximum 21 %). Besides, an increase in circulating pump frequency improved system performance regardless of the temperature difference and working fluid charging amount. This research innovatively investigates the above problems in the application scenario of OTEC, and provides theoretical and data support for the development of OTEC technology.