Low Price Research Articles

Metal‐Organic Framework Materials as Bifunctional Electrocatalyst for Rechargeable Zn‐Air Batteries

AbstractRechargeable Zn‐air batteries offer the advantages of environmental friendliness, safety, low prices and high energy density, and are highly valued. However, the major challenge faced by rechargeable Zn‐air batteries nowadays is the low energy efficiency due to the slow reaction kinetics of electrocatalyst at the air cathode. Bifunctional catalysts are key to the development of Zn‐air batteries by improving their overall performance and long‐term cycling stability. Metal‐organic framework (MOF) materials have shown great benefits as oxygen electrocatalysts in promoting oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). This paper reviews the recent advances of three kinds of MOF materials as bifunctional catalysts for rechargeable Zn‐air batteries. Additionally, this paper also discusses the synthetic design strategy of MOF composite derivatives, and concludes by suggesting the application of MOF materials in the field of rechargeable Zn‐air batteries.

Experimental comparison of cycle modifications and ejector control methods using variable geometry and CO2 pump in a multi-evaporator transcritical CO2 refrigeration system

To reduce the direct global warming impact of refrigerants in HVAC&R applications, low-global warming potential (GWP) refrigerants, including natural refrigerants, have been extensively investigated as alternatives to hydrofluorocarbon (HFC) refrigerants. Among the natural refrigerants, Carbon Dioxide (CO2) offers several advantages, such as excellent transport and thermo-physical properties, being neither toxic nor flammable, and having a low price and high availability around the world. However, the high critical pressure and low critical temperature of CO2 often lead to transcritical operation, resulting in lower efficiency due to the additional compressor power necessary to achieve transcritical operation relative to subcritical HFC cycles. Therefore, a number of cycle modifications are used to enhance the coefficient of performance (COP) of transcritical CO2 cycles to meet or surpass those of HFC cycles. This paper provides a systematic experimental investigation of four such cycle architectures by employing the same multi-stage, two-evaporator CO2 refrigeration cycle test stand, 3 of these configurations in transcritical and 1 in subcritical conditions. The four cycles architectures included intercooling, open economization, an internal heat exchanger and two different ejector control approaches. Specifically, a variable-diameter motive nozzle and a variable-speed liquid CO2 pump located directly upstream of the ejector motive nozzle inlet were analyzed. Based on the experimental data, the maximum COP improvements are 4.64 % and 9.47 % when the ejector and the internal heat exchanger are used, respectively. The CO2 pump, once successfully stabilized, can control the ejector, increase its efficiency by up to 15 % and increase the cooling capacity to a maximum of 6.2 %. Nevertheless, a reduction in COP is measured when the pump is in use; however, unlike the other three different configurations, it was only analyzed under subcritical conditions.

Availability and Pricing of Drugs Prescribed by Otolaryngologists Through a Direct-to-Consumer Pharmacy: Medicare Savings Implications.

High prescription drug prices can financially strain patients and insurers, with substantial clinical repercussions. In recent years, direct-to-consumer (DTC) pharmacies have emerged as potentially lower-cost alternatives for patients to fill prescriptions. We evaluated whether drugs commonly prescribed by otolaryngologists were available at a national DTC pharmacy (Mark Cuban Cost Plus Drug Company [MCCPDC]) and estimated potential Medicare savings from DTC pricing. We identified drugs and prices paid by Medicare Part D plans using the 2021 Drug Spending Dashboard. Our analysis included 16 generic drugs within the MCCPDC formulary, which offered lower prices for 14 (87.5%) drugs. If plans had secured MCCPDC pricing for all 16 drugs, Medicare patients and plans would have saved $2.9 billion (relative reduction: 62.3%) in 2021. Estimated total savings were greatest for budesonide-formoterol ($1.9 billion), dexlansoprazole ($464.6 million), and levothyroxine ($327.4 million). Otolaryngologists and insurers may consider utilizing DTC pharmacies with lower drug prices, though patients may face challenges projecting out-of-pocket costs across pharmacies, medications, benefit phases, and formulary tiers.

Sizing Up the Farm Bill Safety Net

Lower commodity prices and higher production costs over the past couple of years have crop producers concerned about tighter margins and cash flow for their operations. The federal farm income safety net provides substantial support to producers through commodity programs, crop insurance programs, and disaster assistance. Crop insurance has been the primary safety net tool for producers in recent years as commodity prices generally fluctuated at levels above commodity program support levels. Even declining markets in the past couple years left prices that remained above Price Loss Coverage (PLC) support levels and revenue calculations above Agriculture Risk Coverage (ARC) guarantees unless there were significant yield losses at the county level for ARC-CO or the individual farm level for ARC-IC. The outlook is changing however as declining prices run into support levels that are increasing based on the past few years of higher prices. The ARC program provides a revenue guarantee tied to 86% of a benchmark revenue calculated from a five-year moving average price and a five-year moving average trend-adjusted yield. The PLC program provides support if prices fall below the higher of a legislated reference price or 85% of a five-year moving average price. With the higher prices experienced during the past few years, the five-year moving average price has increased and both ARC and PLC support levels have gotten stronger. A look at ARC and PLC protection and payment levels provides a picture of what current support and cash flow may look like and what future support could be under current or future farm legislation.

Import licenses, intermediaries, and price pass-through: Evidence from the Chinese steel market

This study examines the impact of abolishing the exclusive license of importing iron ore on price pass-through in the Chinese steel market. We model the intermediate traders' role in alleviating market uncertainties, which have a critical impact on price pass-through. In addition, we leverage the monthly iron ore import prices and steel market prices in Chinese cities, and employ a difference-in-difference framework to empirically analyze the impact of the import license reform on price pass-through. We show that the reform on average reduces the price pass-through by 15 percentage points, which is around 3 points further in treated cities. Our findings imply the price pass-through hinges on market uncertainties, and the reform, although eliminating double marginalization, makes downstream steel producers have to face market uncertainties directly, and results in a lower price pass-through.

Production, use and nutritive value of fruit wastes as feed in and around the city of West Arsi Zone and Sidama Regional State

The study was carried out to evaluate the availability, use as livestock feed and nutritional value of fruit waste in a few chosen urban (within) and peri-urban (around) areas of West Arsi and Sidama Regional State, Ethiopia. The study areas were chosen using a muti-stage purposive sampling technique and 306 respondents in total-102 from each of Shashemene, Hawassa and Yirgalem-were randomly chosen and interviewed. We used established methodology to examine the nutritional values of six (avocado seed, avocado peel with pulp, papaya pomace, mango, pineapple and banana peels) commonly used fruit waste (FBPs) samples for chemical composition and digestibility analysis. Chi-square was used to examine qualitative results while two-way analyses of variance were used for quantitative factors. Avocado, banana, mango, papaya and pineapple waste were the major useable FBPs for feeding livestock. These wastes were fed to livestock after chopping and wilting without mixing to other feeds. Perishability, health concern, shortage of storage facilities and knowledge were the major limitations whereas low price, high demands, good quality, palatability, use as a source of income and reduction in environmental pollution were the major opportunities for feeding livestock. The range of crude protein (CP) contents were from 5.49 to 19.51 % where papaya pomace contained the highest (p < 0.05) CP content while avocado seed were the lowest (p < 0.05) in CP content. The content of neutral detergent fiber was <45 %, except pineapple peels. The range of acid detergent fiber and acid detergent lignin contents were from 11.23 to 24.29 % and 1.69–13.54 %, respectively. The mean in-vitro dry matter digestibility was within the range of 70.67–88.17 %. In conclusion, the year round production and good nutritive value of fruit wastes make them a choice feed as a source of protein and energy in the study areas. We recommend animal performance evaluation and quantification of these wastes for further use by livestock.

Oxyanion Engineering on RuO2 for Efficient Proton Exchange Membrane Water Electrolysis.

In acidic proton exchange membrane water electrolysis (PEMWE), the anode oxygen evolution reaction (OER) catalysts rely heavily on the expensive and scarce iridium-based materials. Ruthenium dioxide (RuO2) with lower price and higher OER activity, has been explored for the similar task, but has been restricted by the poor stability. Herein, we developed an anion modification strategy to improve the OER performance of RuO2 in acidic media. The designed multicomponent catalyst based on sulfate anchored on RuO2/MoO3 displays a low overpotential of 190 mV at 10 mA cm-2 and stably operates for 500 hours with a very low degradation rate of 20 μV h-1 in acidic electrolyte. When assembled in a PEMWE cell, this catalyst as an anode shows an excellent stability at 500 mA cm-2 for 150 h. Experimental and theoretical results revealed that MoO3 could stabilize sulfate anion on RuO2 surface to suppress its leaching during OER. Such MoO3-anchored sulfate not only reduces the formation energy of *OOH intermediate on RuO2, but also impedes both the surface Ru and lattice oxygen loss, thereby achieving the high OER activity and exceptional durability.

Oxyanion Engineering on RuO2 for Efficient Proton Exchange Membrane Water Electrolysis

AbstractIn acidic proton exchange membrane water electrolysis (PEMWE), the anode oxygen evolution reaction (OER) catalysts rely heavily on the expensive and scarce iridium‐based materials. Ruthenium dioxide (RuO2) with lower price and higher OER activity, has been explored for the similar task, but has been restricted by the poor stability. Herein, we developed an anion modification strategy to improve the OER performance of RuO2 in acidic media. The designed multicomponent catalyst based on sulfate anchored on RuO2/MoO3 displays a low overpotential of 190 mV at 10 mA cm−2 and stably operates for 500 hours with a very low degradation rate of 20 μV h−1 in acidic electrolyte. When assembled in a PEMWE cell, this catalyst as an anode shows an excellent stability at 500 mA cm−2 for 150 h. Experimental and theoretical results revealed that MoO3 could stabilize sulfate anion on RuO2 surface to suppress its leaching during OER. Such MoO3‐anchored sulfate not only reduces the formation energy of *OOH intermediate on RuO2, but also impedes both the surface Ru and lattice oxygen loss, thereby achieving the high OER activity and exceptional durability.

Cross-border competition in the gasoline retail market: Impact of proximity at the German-Polish border

In this article, I analyze how persistently lower gasoline prices in Poland affect the prices set in the German border region. Based on a complete dataset of German gasoline prices and an assessment of driving distances between gasoline stations, I estimate the impact of one additional kilometer of distance to the nearest Polish competitor on the price charged by German gasoline stations. Following the fixed effects filtered estimator approach proposed by Pesaran and Zhou (2018) and controlling for various station characteristics, I find no evidence that German gasoline stations enter price competition with their Polish counterparts. My descriptive analysis of gasoline station infrastructure in the German border region reveals increasingly sparse gasoline station density when approaching the Polish border, along with an increasing share of premium brands. These results may reflect the effect of substantially lower taxes in Poland, discouraging German gasoline stations from locating near the border and effectively ruling out cross-border price competition. Although indirect, my findings suggest the presence of fuel tourism.

Optimization of reversible solid oxide cell system capacity combined with an offshore wind farm for hydrogen production and energy storage using the PyPSA power system modelling tool

AbstractEight scenarios where high efficiency reversible solid oxide cells (rSOC) are combined with an offshore wind farm are identified. Thanks to the PyPSA power system modelling tool combined with a sensitivity study, optimized rSOC system capacities, hydrogen storage capacities, and subsea cable connection capacities are investigated under various combinations of rSOC system capital cost, prices paid for hydrogen, and electricity prices, which give indications on the most profitable scenario for offshore hydrogen production from a 600 MW wind farm situated 60 km from shore. Low electricity prices (yearly average 45 £/MWh) combined with mild fluctuations (standard deviation 6 or 13 £/MWh) call for dedicated hydrogen production when the hydrogen price exceeds 4 £/kg. High electricity prices (yearly average 118 or 204 £/MWh), combined with extreme fluctuations (standard deviation between 73 and 110 £/MWh), make a reversible system economically profitable. The amount of hydrogen which is recommended to be reconverted into electricity depends on the price paid for hydrogen. Comparison of the optimized cases to the default case of a wind farm without hydrogen production improved profit by at least 3% and up to 908%. Comparison to the default case of dedicated hydrogen production, showed that in the case of low hydrogen prices, an unprofitable scenario can be made profitable, and improvement of profit in the case of a profitable default case starts at 4% and reaches numbers as high as 324%.

Development of a water resources utilization model and optimization of the patterns of rice genotypes with system dynamics approach

The system dynamics approach was conducted to optimize genotype patterns in various climatic and water availability scenarios, to address the water productivity improvement of the Sefidrood irrigation network. The studied cropping pattern scenarios were SD1 (the continuation of current trends), SD2 (the reduction in the cultivated area), SD3 (replacing modified crops on an annual basis), and SD4 (increasing the annual cultivated area of Hashemi type rice). Moreover, the impacts of irrigation efficiency improvements and water resources management strategies on the physical and economic water productivity indices were studied. The results indicated that the SD3 scenario has the most positive impact on water productivity with 0.45 kg/m3 increases. However, a questionnaire survey revealed that this scenario that belongs to the increase in the modified genotype area cannot be recommended due to cooking quality and low prices. The Hashemi genotype was the favorite rice among farmers and experts. Also, analyzing the irrigation efficiency improvement scenario showed that this strategy has a limited impact on the physical and economic water productivity. Increasing the capacity of local rainwater storage pools, Ab-bandans, and increasing the drainage water reuse had the highest water productivity in the condition of river water reduction and uncertain water availability.

A Low-Cost and Green Zinc-Iron Battery Achieved by Ethaline Deep Eutectic Solvent.

Deep eutectic solvents (DESs) were considered as a potential electrolyte because of their low price, harmless to environment and wider electrochemical window potential compared to water. In this work, Fe(III)/Fe(II) and Zn(II)/Zn redox couples were used as the positive and negative active materials, respectively, in a DES system using choline chloride and ethylene glycol in a molar ratio of 1 : 2 (ethaline). The possible working mechanism of the battery was studied by cyclic voltammetry, spectroscopic and simulation methods. The effects of different temperatures, concentrations of zinc ions in the anolyte and current densities on battery performance were evaluated. The results showed that the designed zinc-iron battery should preferably be operated at a current density of 0.5 mA cm-2 and the temperature of 313~323 K, which will improve the energy efficiency and maintain a high coulombic efficiency. The variation of cycle performance test presents a different pattern from the usual batteries, which is due to the effect of RO- group. At 313 K and 0.5 mA cm-2, the coulombic efficiency increases from 14.1 % to 100.2 % after 46 cycles, and then remains at about 100 % during the rest 54 cycles, which demonstrates a good cycle stability of DES-based zinc-iron battery.

Environmental Discourse and Firm Value: Evidence From Conference Calls

We examine environmental discourse in conference calls and the relation between this discourse and firm value. We measure the amount of environmental discourse as the frequency count of environmentally-related topics in the transcripts of conference calls. We argue that greater environmental discourse in conference calls indicates firms’ prioritization of environmental issues. Evidence indicates that greater amounts of environmental discourse are associated with lower share price and higher cost of capital, which we interpret as reflecting the relatively higher costs of environmentally responsible operations in excess of firm-specific benefits. Additional analysis examining general environmental, social, and governance (ESG), especially social and governance, discourse shows that it is associated with lower cost of capital and higher share price, suggesting that prioritization of social and governance issues does not imply higher operational costs and indeed may signal firm-specific value creation.

Empirical Study on BYD Stock Price Prediction Based on LSTM Model

This study employs Long Short-Term Memory (LSTM) neural network models for stock price prediction. LSTM models excel in managing nonlinearities and time-series dependencies in data, thereby enhancing the accuracy of stock price forecasts, reducing investment risks, and increasing returns. Investors can reasonably use the LSTM model to predict stock prices and obtain greater returns. The research utilizes eight years of historical data from BYD, including opening prices, closing prices, highest prices, lowest prices, and trading volumes, as training data. By adjusting various hyperparameters such as epochs, learning rates, and training-test ratios, the study analyzes their impact on the predictive accuracy of the model and identifies optimal configurations through comparative experimental methods. We found that the best parameters were when epoch number was 25, training ratio was 90:10 (minimum mean square error was 0.00175572) and 4 years of training data was selected as the training set (minimum mean square error was 0.00146477).

Measurement and Validation of Market Power in China’s Log Import Trade—Empirical Analysis Based on PTM Model and AIDS Model

China is the world’s largest importer of logs, possessing the scale to exert significant influence in the international market. This paper uses a fixed-effect variable coefficient Pricing-to-Market panel model to measure China’s market power in log import trade. It also utilizes the Almost Ideal Demand System model from an elasticity perspective to explore the market behavior characteristics of various source countries in China’s log import trade, thereby validating the mechanism of market power. The results indicate that: ① China’s main trading partners can be categorized into four groups according to their market power in the log import trade. Specifically, China holds superlative market power in log imports from Indonesia, Malaysia, and Myanmar; holds strong market power in log imports from Russia, the Democratic Republic of the Congo, and Mozambique; holds weak market power in log imports from Papua New Guinea, Equatorial Guinea, France, Germany, Australia, and New Zealand; and holds no market power in Japan, Cameroon, and the United States. ② As China’s expenditure on log imports increases, there is a tendency to purchase high-quality precious wood and a greater concern for the legality of market transactions. Consequently, China is anticipated to augment its imports from source countries with no or weak market power. ③ The simple price elasticity of log imports from each source country is negative. Source countries with stronger market power tend to increase prices to achieve higher total revenue, while those with weaker market power are more inclined to lower prices to achieve the same. ④ Log products from various source countries are complementary in the Chinese market, indicating that China’s substantial demand for logs relies on the simultaneous supply from multiple countries and diverse wood types. Based on the existence or absence of market power in China’s log import trade, this paper provides targeted insights into enhancing international market power and reducing trade losses.

Relationship Between Participation of In-Hospital Cardiac Rehabilitation and Regional Characteristics in Japan - Insight From the Japanese Registry of All Cardiac and Vascular Diseases and the Diagnosis Procedure Combination.

The influence of various regional backgrounds on participation in cardiac rehabilitation (CR) remains underexplored. We investigated the regional characteristics that potentially promote CR participation. This was a nationwide cross-sectional cohort study using the Japanese Registry of All Cardiac and Vascular Diseases and the Diagnosis Procedure Combination. This study included a cohort of 2.7 million inpatients hospitalized between April 2012 and March 2021. The CR participation rate for each hospital was calculated as the percentage of eligible patients who underwent CR during their admission. Among all hospitals, those that do not perform CR were defined as No-CR hospitals. The remaining hospitals were categorized into High- and Low-CR hospitals based on the median level of the CR participation rate (41.5%). High-CR hospitals had significantly smaller medical service areas (P<0.0001), a higher number of physicians per population (P<0.0001), higher air temperature (P=0.02), and fewer primary industry workers (P=0.005) than the other 2 groups. Logistic regression analyses revealed that a lower consumer price index was a significant regional factor that characterized High-CR hospitals, and a lower population aged ≥65 years was a factor approaching significance that characterized the region where High-CR hospitals are located. High-CR hospitals were found in regions with a lower consumer price index and a trend towards a lower population aged ≥65 years.

Pricing Strategies for O2O Catering Merchants Considering Reference Price Effects and Unconditional Coupons

Coupon marketing is an important promotion model for the O2O catering supply chain. As a well-known catering O2O platform in China, Meituan provides its members with the opportunity to buy unconditional coupons at low prices, and it is very popular with consumers. It is worth studying how catering merchants develop pricing and promotion strategies considering consumers’ reference price effects in two scenarios: participating and not participating in coupon stacking (S-PICS/S-NPICS). In order to explore the pricing mechanism of meals, two models using Stackelberg games are established considering some exogenous variables, such as commission rate, reference price, and sensitivity of consumers to coupon prices. The results show that (1) the reference price has a great influence on the maximum profits of catering merchants, varying in different scenarios; (2) in S-NPICS, the merchants’ maximum profit increases with an increase in the reference price, while, in S-PICS, an increase in the reference price leads to a decrease in merchants’ maximum profit; (3) the profit of merchants in S-PICS is higher than that in S-NPICS, indicating that merchants can benefit from coupon stacking; (4) when the commission rate of the coupons increases, the merchants in both S-PICS and S-NPICS should raise their online meal prices to obtain higher profits. This study provides a balanced reference for pricing strategies and coupon promotion strategies in different scenarios through the use of deduction and simulation methods, which is conducive to the sustainable development of the O2O catering supply chain. As consumers enjoy using these coupons, including unconditional ones, it is suggested that merchants and Meituan should focus on coupon promotion and develop better dining pricing strategies.

Impact and critical factors in Heijunka implementation an action research study

Purpose: Although Heijunka (production levelling or smoothing) is a lean tool designed to balance changing customer needs and production efficiency, this study aims to analyze the impact of Heijunka and identify various factors which can generally affect its successful implementation.Design/methodology/approach: We adopted an action research (AR) approach to analyze the consequences of implementing Heijunka in a factory that successfully operates in a lean environment but faces demand that is increasingly less predictable, and customers who require ever more individualized products at low prices with extremely demanding delivery timescales. An estimation of costs was carried out to compare three alternative production planning scenarios: (1) make to order (MTO) production, (2) weekly levelled production and (3) production with minimal changeovers.Findings: The analysis of the impact of implementing Heijunka in this factory demonstrated that MTO production planning without Heijunka is the most efficient option for the factory. We explore the reasons why Heijunka is not suitable for this factory even though other lean principles and tools have been successfully implemented. In this way we identify the main factors which might influence the successful implementation of Heijunka, such as changeover time, the number of different product types (and lot sizes) and the capacity that the production lines are running at.Originality/value: Based on close collaboration between researchers and practitioners in the field of Operations Management, this AR study provides important information for decision making in lean environments (applying Heijunka or not), as well for the advancement of the academic debate about successful lean implementation nowadays.

Patient out-of-pocket expenditure in primary care comparing high income, middle income and low-income countries

Background: Out-of-pocket health expenditures (OOPHE) in primary care can pose a significant financial burden on individuals and households, particularly in low- and middle-income countries. Understanding the factors influencing OOPHE is crucial for developing effective policies to improve healthcare access and affordability. Objective: This systematic review aimed to identify and analyze the factors influencing OOPHE in primary care settings across high-, middle-, and low-income countries. Methods: A comprehensive search of electronic databases was conducted to identify relevant studies. Included studies were assessed for quality and data were extracted to identify key factors influencing OOPHE. Results: Demographic characteristics, socioeconomic factors, healthcare utilization, system factors, and cultural factors were all found to influence OOPHE. Lower income levels, limited insurance coverage, frequent healthcare utilization, and higher disease severity were consistently associated with higher OOP costs. Conclusion: The findings highlight the significant burden of OOP expenditures on individuals and households. Policymakers should prioritize strategies to expand health insurance coverage, improve access to primary care services, negotiate lower prices for healthcare goods, and address underlying socioeconomic factors. Further research is needed to explore the impact of specific interventions and the role of cultural factors in shaping OOP expenditures.

Early prediction of fabric quality using machine learning to reduce rework in manufacturing processes

The increasing competition and rapid technological advancements in today's business world have raised customer expectations. People now expect quick delivery, low prices, and high-quality products. As a result, companies must adapt to this competitive environment to survive. Rework, which is a significant cost in production, increases expenses, reduces production efficiency, and can lead to customer attrition. Research shows various efforts across different sectors to reduce rework, although there is still a gap in the textile sector's fabric dyeing units. Common problems in these units include non-retentive colors, customer dissatisfaction with shades, and repeated dyeing due to environmental factors or dye vat issues. This study uses logistic regression and artificial neural networks models from machine learning to predict which fabrics will need rework, using data from a textile company in Bursa. The analysis indicates that artificial neural networks models perform better.