Optimal Reduction Rate Research Articles

Determining optimal range of reduction rates for nitrogen fertilization based on responses of vegetable yield and nitrogen losses to reduced nitrogen fertilizer application

Vegetable production is commonly accompanied by high nitrogen fertilizer rates but low nitrogen use efficiency in China. Reduced fertilization has been frequently recommended in existing studies as an efficient measurement to avoid large amount of nutrient loss and subsequent nonpoint source pollution. However, the reported responses of vegetable yield and nitrogen losses to reduced fertilization rates varied in a large range, which has resulted into large uncertainties in the potential benefits of those recommended reduction rates. Thus, we constructed the relationship between responses of nitrogen losses and vegetable yield to reduced nitrogen fertilization rates to determine the optimal range of reduction rates for nitrogen fertilization in a proportional form based on data reported in literatures across China's mainland, and evaluated the roles of greenhouse, managing options, and vegetable species on the responses. The relationships were constructed separately for 4 subregions: Northern arid and semiarid, loess plateau regions (NSL), Temperate monsoon zone (TMZ), Southeast monsoon zone (SMZ), Southwest zone (SWZ). The optimal nitrogen fertilizer reduction range for the TMZ, SMZ and SWZ were 51 % to 67 %, 40 % to 66 % and 54 % to 80 %, respectively and no reduction for NSL. Vegetable yields were not be sacrificed when fertilizations were reduced within the optimal ranges. Greenhouse and managing options showed no significant effect on the responses of both vegetable yield and nitrogen losses by the optimal reduction range but vegetable species played a relatively important role on the responses of vegetable yield. This indicated that the optimal reduction rates can be effective on reducing nitrogen loss in both open-field and greenhouse conditions across China's mainland without extra managing options. Therefore, the optimal reduction rates can still serve as a good starting point for making regional plans of nitrogen reduction that help balancing the chasing of high vegetable yield and low nitrogen loss.

Remediation of high-concentration Cr(VI)-contaminated soils with FeSO4 combined with biostimulation: Cr(VI) transformation and stabilization

Efficient and sustainable technologies for cleaning up of hexavalent chromium (Cr(VI)) contaminated soil are under urgent demand. In this study, chemical reduction and biostimulation were combined to remediate contaminated soil with a high concentration of hexavalent Cr(VI) to compensate for the shortcomings of single-treatment technology. The Cr(VI) concentration, Cr speciation, and bacterial diversity of the contaminated soil were measured after combined remediation with ferrous sulfate (FeSO4) and different electron donors. The changes in various indexes in the soil after microbial death were also studied. The results indicated that the optimal reduction rate of Cr(VI) was as high as 95.20% when 10% FeSO4 was combined with lactic acid. The water-soluble fraction of Cr with the highest toxicity in the soil was almost completely converted into other stable fractions. Stabilization experiments proved that Cr(III) in the remediated soil did not revert to Cr(VI) after microorganism death, and had a good stabilization effect. The bacterial diversity results indicated that Acinetobacter spp. and Pseudomonas spp. were the dominant species during the biostimulation process and might be involved in the reduction of Cr(VI).

Evaluating the optimal air pollution reduction rate: Evidence from the transmission mechanism of air pollution effects on public subjective well-being

Estimation of the effects of air pollution on residents' subjective welfare, which is always monetized as willingness to pay (WTP), is essential for policymakers to set the optimal abatement targets. This paper adopts Life Satisfaction Approach to explore the mechanism of air pollution affecting residents' subjective well-being (SWB), and calculates the optimal abatement rate. Based on CGSS data, we use the Probit model and the instrumental variables method to conduct empirical analysis. Results show that the positive indirect effect of air pollution through economic growth channel covers nearly 1/3 of the negative direct effect on SWB, which reduces people's willingness to pay for pollution control. Under the maximization of SWB, the optimal reduction rate is 62.857%. To achieve the optimal rate, about 5% of per capita GDP would have to be sacrificed, equivalent to a 20% increase in physical capital stock per capita, or a 13% boost of the human capital stock. When residents have lower education and higher self-rated health, the transmission mechanism amplifies the extent to which the indirect effects mask the direct effects, and the optimal reduction rate drops to 50%. • Explore the effects of air pollution on residents' SWB by LSA. • Construct the ventilation coefficient as the instrument to alleviate the endogeneity. • Further gauge the public's WTP for air pollution treatment. • Estimate the optimal air pollution rate of China by happiness data.

Digital-Based Healthy Bra Top Design That Promotes the Physical Activity of New Senior Women by Applying an Optimal Pressure.

A bra use can reduce physiological and physical functions because of clothing pressure, which can be a problem for new senior women starting to lose physical function. The present study presents a bra top design development method for promoting new senior women’s physical activity by identifying problems related to bras’ effects on women’s health and minimizing clothing pressure. The analysis utilized the 3D scan data of 42 adult women (age range: 50s) from the 5th Size Korea Project. Bra top design elements were extracted based on new senior consumers’ needs. We developed an average wireframe reflecting the new senior’s physical characteristics, and a standard body form was developed through surface modeling. To produce a consumer-oriented bra with a body shaping effect and reduced clothing pressure that would not affect physical activities, a three-dimensional pattern was developed applying an optimal reduction rate of 80%. To verify the bra’s adequacy for the body form of new senior women, two market-available bras were selected and fit-compared to the developed product. The developed bra received higher expert appearance evaluation and 3D virtual clothing evaluation scores. This study is significant because by using virtual fitting technology, it provides foundational data to quantify the quality of fashion products.

Investigating groundwater vulnerability variation under future abstraction scenarios to estimate optimal pumping reduction rates

Groundwater vulnerability variation over time due to groundwater depth variation caused by pumping reduction is an issue of great interest that should be properly investigated; this is because pumping reduction results in groundwater level increase on the one hand and groundwater vulnerability increase, as a result of groundwater depth decrease, on the other hand. In this context, the present study introduces a novel approach, which considers the spatio-temporal variation of groundwater vulnerability and at the same time focuses on the relationship between vulnerability change and pumping reduction to estimate the optimal pumping reduction rate (i.e. the highest rate of pumping reduction under which the highest increase in groundwater levels occurs without an increase in groundwater vulnerability taking place) in over-exploited and contaminated aquifers. In a first stage, a dynamic and time-dependent approach involving the linkage between a GIS-based DRASTIC model and a groundwater flow model was developed in order to determine groundwater vulnerability changes under different pumping reduction rates (0%, 10%, 20%, 30% and 40%), and thus to produce the necessary data sets for investigating their relationship. Subsequently, regression analysis was conducted to define this relationship and estimate the optimal pumping reduction rate. Our implementation of the methodology showed that groundwater vulnerability displays small changes during the projection period for all reduction rates, while decreasing for 0% and 10% reduction of withdrawals and increasing for 20%, 30% and 40% reduction. After finding that a quadratic equation accurately describes the relationship between vulnerability change and pumping reduction (R2 = 0.999), an optimal reduction rate of 16.4% was estimated. By confirming that no change in vulnerability occurs under this value during the projection period, the validity of the equation defined was affirmed.

Reduction and Adsorption Mechanism of Chromium Hexavalent in Electroplating Industry Passivation Tank Effluent Using New Linz-Donawits Slag Waste Material.

Hexavalent chromium Cr(IV) is widely used as electroplating agent to produce a hard, durable coating to a metal with excellent wear and corrosion resistance properties. Yet the effluent of this process needs to be carefully treated as Cr(IV) has been recognized as hazardous, a known carcinogen and mutagen to the human body. Current treatment of Cr(IV) in electroplating industry is by using sodium metabisulfite (SMBS) with a maximum reduction of 100% in a solution of pH 2. Nevertheless, despite the remarkable performance, the application of SMBS as reducing agent generates a massive amount of sludge which eventually will be disposed to the landfill. It also poses detrimental health effects due to the release of hydrogen sulfide (H2S) and sulfur dioxide (SO2) gas. Thus, a less harmful reducing agent was studied to replace SMBS in Cr(IV) reduction process. Linz-Donawitz (LD) slag has been discovered to be a good reducing agent due to the presence of Iron in the form of Fe2+. The characterization of electroplating industrial effluent using ICP-MS shows a highest composition of Chromium which is 1614.6mg/L. Meanwhile, characterization of LD slag shows that the major component is Ferrous (II) Oxide, (FeO) which constitutes 37.2% of the total mass. By using SMBS as reducing agent, 8 ml of 4% v/v SMBS concentration is required to reduce 40% of Cr(IV) in the sample solution. The optimum treatment duration of Cr(IV) using LD slag is found to be 5 minutes and the best pH of the sample solution for optimal reduction rate is 2. In addition, smaller particle size of the LD slag is more advantageous as smaller amount of LD slag is required to completely reduce Cr(IV) concentration in the solution. However, the best particle size is 0.425mm because the reduction rate is more controllable. ORP value at zero Cr(IV) concentration is found to be ±488 mV.

Scenario analysis on subsidy policies for the uptake of electric vehicles industry in China

The development of the electric vehicles (EVs) industry increasingly attracts attention from many countries all over the world, which aims to reduce transportation carbon emissions. Existing studies only focus on the impact of government subsidies on the performance of EVs industry, but overlook the interaction of subsidy policies and the performance of EVs industry. This research therefore develops a system dynamics (SD) model to describe the feedback relationship among subsidy policies, EVs sales, and the uptake of EVs. Different scenarios of combined subsidy policies are designed to simulate and analyze the future development of China's EVs industry. The results indicate that an optimal reduction rate chosen by the government would enable the EVs industry to develop steadily when the purchasing subsidy is going down. Considering combined effects of multiple subsidies, a policy portfolio of industrial subsidy and purchasing subsidy could improve the efficiency of government funds in promoting the development of EVs industry. A dynamic industrial subsidy outperforms a static purchasing subsidy in terms of government funds saving. In addition, a subsidy increase for charging facilities is still an important supplementary policy to ensure the uptake of EVs, even if the government has adopted an appropriate reduction rate of purchasing subsidies. Based on these results generated from the SD model, policy suggestions are provided to advance the development of EVs industry in China and policy implications are also helpful for other countries.

Bio-regeneration of spent Fe3O4 laden quaternary-ammonium shaddock peel after perchlorate capture: Considering the oxygen, coexisting anions, bio-fouling and indirect bio-regeneration

A new bio-sorbent based on the shaddock peel was prepared for perchlorate capture. The shaddock peel was introduced with quaternary-ammonium groups and Fe3O4 nanoparticles, forming the Fe3O4 laden quaternary-ammonium shaddock peel (Fe3O4-QA-SP). Bio-regeneration of perchlorate laden Fe3O4-QA-SP considering the oxygen, coexisting anions, bio-fouling and indirect bio-regeneration was conducted. Results indicated that the bio-reduction rate increased as the increase in the amounts of perchlorate laden on Fe3O4-QA-SP and the optimal reduction rates (0.0226–0.0865mgp/mgss/d) were obtained at pH 7.0. Bio-reduction of laden perchlorate in the presence of Cl− (indirect bio-regeneration) help to keep a relatively high capture capacity (86.5%) of Fe3O4-QA-SP for perchlorate even after 7 cycles of indirect bio-regeneration. In contrast, only 58.3% of capture capacity was left after 3rd of direct bio-regeneration. Bio-fouling was also observed on surface of Fe3O4-QA-SP after sterilization process.

The Usage Analysis and Policy Choice of CNG Taxis Based on a Multi-stage Dynamic Game Model

The promotion and application of low-carbon energy has become a basic energy policy in China. In the taxi industry, the adoption of natural gas is a typical reflection of the use of low-carbon energy, however, the application of CNG taxis in practice is difficult because of the ignorance of consumer behaviour choices and the lack of consideration of the reforming and maintenance costs of CNG taxis in practical use during the implementation of this policy. In this paper, the construction of a multi-stage dynamic game model is proposed: this is used to analyse the complex dynamic relationships among consumers, the taxis, and the policy-making behaviours of government. By the means of backward induction, a conclusion is drawn such that government should determine the subsidy coefficientper unit of product as well as the carbon taxand the optimal reduction rate of carbon emissions confirmed by operators determination. Based on these, concerning the behavioural choices among consumers, taxis, and government, this paper draws five conclusions, which answer the problems concerning whether, or not, the government should levy a carbon tax and subsidise such operations as well as how much that financial levy and subsidy should be. Besides, this paper also makes a value judgment of the future format/mode of taxi operations. The study shows that, with the increasing subsidy, the competitive advantages of the CNG taxis are strengthened while the revenues of oil-fired taxis decrease constantly, which forces oil-fired taxis out of the market. At the same time, the service prices of both kinds of taxis are proportional to the money paid by consumers and the positive impacts of service prices on CNG taxis are greater than that on oil-fired taxis.The carbon tax standard set by government can play a proper role only if it gives consideration to the interests of both consumers and CNG taxis.

The Reduction Rate of Serum Sodium and Mortality in Patients Undergoing Continuous Venovenous Hemofiltration for Acute Severe Hypernatremia

BackgroundThe excessive correction of acute hypernatremia is not known to be harmful. This study aimed to evaluate whether a reduction rate of serum sodium (RRSeNa) > 1mEq/L/hour in acute severe hypernatremia is an independent risk factor for mortality in critically ill patients undergoing continuous venovenous hemofiltration (CVVH) treatment. Materials and MethodsFor this retrospective study, we reviewed records of 75 critically ill patients undergoing CVVH treatment for acute severe hypernatremia between March 2011 and March 2015. ResultsThe 28-day mortality rate of all patients was 61.3%. In multivariate Cox regression analyses, a reduction rate of serum sodium (RRSeNa) > 1mEq/L/hour (hazard ratio = 1.89; 95% CI: 1.03-3.47; P = 0.04), Acute Physiology and Chronic Health Evaluation II score and vasopressor dependency (yes or no) had a statistically significantly effect on mortality. Once we excluded patients with an RRSeNa ≤ 0.5mEq/L/hour, only RRSeNa > 1mEq/L/hour (hazard ratio = 2.611; 95% CI: 1.228-5.550; P = 0.013) and vasopressor dependency had a statistically significant influence on mortality in multivariate regression. ConclusionsIn addition to the Acute Physiology and Chronic Health Evaluation II score and vasopressor dependency, the excessive correction of acute severe hypernatremia was possibly associated with mortality in critically ill patients undergoing CVVH treatment. The optimal reduction rate of acute hypernatremia should be extensively studied in critically ill patients.

Studies on Technological Parameters of Optimal Soft Reduction about Superwide Slab Caster

Based on practical production technology, using some methods like segregation index analysis, the research is focused on the relationship between the maximum segregation index of carbon, phosphorus, sulfur in superwide slab and rolling reduction, reduction ratio, reduction rate of superwide slab caster. During the process of soft reduction, the theory that the minimum of the maximum segregation index corresponds to the technological parameters like optimal rolling reduction, optimal reduction ratio, optimal reduction rate of the superwide slab caster can be provided as a theoretical basis for the production of superwide slab.

Comparative studies on "sandwich" rolling and flat rolling in processing Ag/Bi-2223 tapes

The normal rolling method is commonly used for intermediate mechanical deformation in the powder-in-tube process to make Ag-clad Bi-based superconducting tapes. To compare the effects of different reduction processing on the superconducting properties of Ag/Bi-2223 tapes, the reduction rate dependence of the critical current densities J/sub c/ of tapes processed by three methods, including normal rolling, pressing and "sandwich" rolling, has been systematically studied. Experimental results show that J/sub c/ dependence on the reduction rate for the three processes follows the same law. There is an optimal reduction rate in each case, which gives the highest physical density and the highest J/sub c/. When the reduction rate increases, J/sub c/ initially increases, reaches a maximum and then diminishes. The density-reduction rate follows a corresponding trend. However, the maximum J/sub c/ of the Ag/Bi-2223 tapes made using "sandwich" rolling is 35% higher than is the case for normal rolling even though the tapes in both cases have the same density of the oxide core. XRD analysis shows that the significant difference in J/sub c/ of tapes processed using the three different intermediate deformation procedures cannot be attributed to the phase composition. SEM images show that normally rolled tapes have much higher density of microcracks than "sandwich" rolled tapes. It is evident that the J/sub c/ of a tape is strongly dependent on oxide core density and deformation procedure.

Magneto-optical images of Ag/Bi-2223 tapes processed by flat rolling, "sandwich" rolling and pressing

Magneto-optical imaging (MOI) has been used for study Ag/Bi-2223 tapes processed using flat rolling, "sandwich" rolling, and pressing methods for the intermediate mechanical deformation in powder-in-tube process. The results show that not only the density of the microcracks but also their distribution affect J/sub c/. Rolled tapes have a higher density of microcracks than pressed tapes. Although the flat rolled tape and "sandwich" rolled tape have the same level density of microcracks at the same reduction, the cracks in the former are more in the transverse direction than in the latter. In all three cases, J/sub c/ reaches a maximum value at an optimal reduction rate.

The effect of intermediate deformation processing on J c of Ag/Bi-2223 tapes

Normal rolling, “sandwich” rolling, pressing, hot-pressing, and cryogenic pressing were used as the intermediate mechanical deformation for making Ag-clad Bi-based superconducting tapes. Magneto-optical imaging results were taken to study the density of the microcracks and the distribution of the microcracks. J c of sandwich rolled tape is 35% higher than the normal rolled tape. J c and relative density of the tapes with three different processes (normal rolling, “sandwich” rolling, and pressing) are increased when increasing the reduction rate, then reached a peak at optimal reduction rate and decreased at large reduction rate.