Unit Energy Research Articles

GREEN DATA CENTERS: SUSTAINABLE PRACTICES FOR ENERGY-EFFICIENT IT INFRASTRUCTURE

The digital age has led to a surge in connectivity, innovation, and information exchange, but it has also led to escalating energy consumption by data centers. Green data centers have emerged as a transformative solution, embodying a commitment to sustainability through eco-friendly practices and cutting-edge technologies. Key principles of green data centers include energy-efficient hardware, renewable energy integration, advanced cooling systems, and resource optimization strategies. Energy-efficient hardware involves replacing outdated servers, storage systems, and network equipment with energy-efficient alternatives, such as virtualization technologies. This reduces power consumption and sets the stage for a more sustainable and technologically advanced data center infrastructure. Renewable energy integration reduces dependence on traditional power grids and fossil fuels, ensuring an eco-friendlier energy supply. Advanced cooling systems, such as liquid immersion, hot aisle containment, and free air cooling, optimize efficiency while maintaining ideal server temperatures. Resource optimization ensures that every unit of energy is utilized judiciously, contributing to the overarching goal of sustainability. The transition to green data centers presents challenges such as upfront investment costs, integration of renewable energy with fluctuating power grids, and technical complexities associated with advanced cooling systems. However, there are substantial opportunities, including reduced operational costs, improved brand image, and compliance with environmental regulations. Emerging trends in green data centers include artificial intelligence and edge computing, which enable optimization of cooling systems, prediction of peak workloads, and dynamic resource management. By prioritizing energy efficiency, embracing innovative technologies, and staying attuned to emerging trends, data centers can play a pivotal role in forging a more sustainable digital future.
 Keywords: Green Data Centers, Sustainability, Energy Efficiency, It Infrastructure, Edge Computing, Artificial Intelligence.

A novel approach of jet polishing for interior surface of small-grooved components using three developed setups

It is a challenge to polish the interior surface of an additively manufactured component with complex structures and groove sizes less than 1 mm. Traditional polishing methods are disabled to polish the component, meanwhile keeping the structure intact. To overcome this challenge, small-grooved components made of aluminum alloy with sizes less than 1 mm were fabricated by a custom-made printer. A novel approach to multi-phase jet (MPJ) polishing is proposed, utilizing a self-developed polisher that incorporates solid, liquid, and gas phases. In contrast, abrasive air jet (AAJ) polishing is recommended, employing a customized polisher that combines solid and gas phases. After jet polishing, surface roughness (Sa) on the interior surface of grooves decreases from pristine 8.596 μm to 0.701 μm and 0.336 μm via AAJ polishing and MPJ polishing, respectively, and Sa reduces 92% and 96%, correspondingly. Furthermore, a formula defining the relationship between linear energy density and unit defect volume has been developed. The optimized parameters in additive manufacturing are that linear energy density varies from 0.135 J mm−1 to 0.22 J mm−1. The unit area defect volume achieved via the optimized parameters decreases to 1/12 of that achieved via non-optimized ones. Computational fluid dynamics simulation results reveal that material is removed by shear stress, and the alumina abrasives experience multiple collisions with the defects on the heat pipe groove, resulting in uniform material removal. This is in good agreement with the experimental results. The novel proposed setups, approach, and findings provide new insights into manufacturing complex-structured components, polishing the small-grooved structure, and keeping it unbroken.

Wrap-around loop pulsating heat-pipe heat exchanger for enhancing the energy efficiency of high-tech cleanroom HVAC systems

Abstract To maintain strict temperature, humidity, and cleanliness requirements, the cleanrooms of high-tech semiconductor fabrication plants have heating, ventilation, and air conditioning (HVAC) systems, which require substantial amounts of energy. To reduce energy consumption, this study proposes using a wrap-around loop pulsating heat pipe (WLPHP) heat exchanger comprising a pulsating heat pipe for precooling high-temperature outdoor air to reduce relative humidity. The heat absorbed by the heat-pipe evaporator is then transferred to the condenser and released, reducing the energy required to subsequently reheat the air with an HVAC system. The experimental results reveal that the system reduces the required reheating energy and increased the moisture removal rate per unit energy consumption by an average of 24.8% and 33% compared with a typical heat exchanger. Hence, using the WLPHP heat exchanger in HVAC systems could provide large energy savings.

World development assessment in an invariant coordinate system of energy units: The newly industrialized economies perspectives

The purpose of the article is to present the results of analysis of newly industrialized countries in the context of sustainable development. The study took place within the framework of the Kaldor’s structural-economic model of the gross domestic product and the energy flow model, using the socio-economic systems power changes analyzing method. Within the context of the approach, an invariant coordinate system in energy units is considered, the necessary conditions for sustainable development are formulated, and the main parameters for assessing the potential for growth and development are determined. The article focuses on key issues regarding new concepts of sustainable development and methodology for assessing sustainable development using the concept of socioeconomics useful power for the countries of the newly industrialized economy a group of emerging countries that have made in short time period a qualitative transition in socio-economic development. Based on a new definition of sustainable development in energy units, development trends are formulated for the selected countries during 20 years for the period 2000–2019. Results of the study can be used to planning for the transition to sustainable development. The data of the Central Statistical Office of European Union, the World Bank and the United Nations Organization were used for calculations. Initial interpretation of the calculated data has been done for the largest newly industrialized countries Brazil, India and China in terms of the gross domestic product in the period 1990–2019. For comparison, data on USA are presented as countries with advanced economy.

Comparison of Energy Consumption to Economic Growth in Developing Asian and Developed Asian Countries

This study will analyze the comparative use of Economic Stability Comparisons from the Consumption of Fossil and New and Sustainable Energy: Developed and Developing Countries in Asia, including developing countries Indonesia, Malaysia and Thailand and developed countries Japan, the United Arab Emirates and South Korea. This study uses a panel cross-section/observation form of 6 Asian countries by taking the category of 3 developing countries and 3 developed countries. The time series takes the period 2005-2021, using the ordinary least squares (OLS) method. The results of a study of 3 developing Asian countries namely Indonesia, Malaysia and Thailand GDP Per Unit Energy Use and consumption of sustainable energy have a positive and significant influence and consumption of fossil energy has no effect on growth. In the equation model of 3 developed Asian countries, namely Japan, the United Arab Emirates and South Korea, GDP per Unit Energy Use has a positive and significant influence, sustainable energy consumption has no effect on economic growth, fossil energy consumption has a positive and significant influence in region 3 developed Asian countries during 2005-2021.

Techno-economic and life-cycle analysis of single-step catalytic conversion of bioethanol to fuel blendstocks over Ni-doped HZSM-5 zeolite catalyst

This work presents techno-economic and life-cycle studies focusing on the catalytic conversion of ethanol into hydrocarbon fuel blendstocks. These analyses benefit from recent advancements in catalyst and process development. The consolidated alcohol dehydration and oligomerisation for ethanol-to-hydrocarbon (CADO-ETH) conversion approach, described here, achieves a single-step transformation of wet ethanol vapour into hydrocarbons and H2O using a Ni-doped HZSM-5 catalyst. Catalyst cost estimation using the CatCost model showed that commercial synthesis of Ni/HZSM-5 incurred significant processing costs, which varied greatly depending on the manufacturing scale. Hence, catalyst production using 100 % and 50 % baseline scale production (BSP) requirements resulted in net catalyst costs of $31.4 and $69.9/kg, respectively. Although current CADO products closely resemble gasoline blendstocks, they can also be blended with gasoline fuel at low levels. There is potential for higher-level blending in the future. The operating and annualised capital costs for converting wet ethanol into fuel blendstocks were predicted to be $0.05/L at present and projected to decrease to $0.03/L in the future. This cost is comparable to the unit energy cost of synthesising anhydrous ethanol from wet ethanol, which is $0.02/L. At an oil price of 100 $/bbl, the expected minimum selling prices for the fuel blendstocks produced by CADO are similar to the prices for conventional gasoline. However, at an oil price of $60/bbl, the estimated minimum selling prices for CADO-derived blendstocks are not competitive with conventional gasoline. Nevertheless, considering existing production incentives, the projected minimum selling price for gasoline blendstock is comparable to the oil price of $60/bbl. The LCA shows that the CO2 emissions of gasoline produced from crude oil are 90.2 gCO2 e/MJ, which is 25 %, 53 % and 63 % more than the emissions of gasoline produced from corn starch, sugarcane, and cane cellulose, respectively. The results of this study indicate that the single-step CADO-ETH technology is promising for the production of renewable fuels and offers a potential pathway to reduce the carbon footprint.

Comprehensive analysis of line losses and valuation of energy savings in optimized photovoltaic array subjected to partial shadings

In this manuscript, an attempt is made to reconfigure the conventional total cross-tied (TCT) array through a novel optimized SuDoKu (OPSDK) static reconfiguration technique. This approach helps to reduce the line losses occurring due to increased wire length and simultaneously diminishes the adverse effects of accumulated shadings in close vicinity by diffusing it across the photovoltaic array (PVA). The MATLAB/Simulink platform is used to study the variations in the performance of various existing topologies and the proposed OPSDK PVA model under various shading scenarios such as bottom-right corner, bottom-left corner, top-right corner, top-left corner and drifted-locus centre. The performance is monitored with regard to the specific characteristics viz., % fill-factor, mismatch power losses, % power loss, % efficiency, global maximum power point, maximum voltage, maximum current, local maximum power points (LMPPs), number of LMPPs, misleading power loss, current loss, voltage loss, % execution ratio, % power improvement, % thermal voltage, % power enhancement ratio, line loss and annual energy saving. Theresults show that the proposed OPSDKmethod generates 28.12852 kWh energy units per day, which is maximum when compared to other five topologies viz. SuDoKu (SDK), futoshiki SuDoKu (FSDK), skyscraper SuDoKu (SKYSDK), modified SuDoKu (MSDK), ancient chinese magic square (ACMS). Consequently, the annual income generatedby [9×9] SDK, FSDK, SKYSDK, MSDK, ACMS and OPSDK PVAs is ₹ 150,839.54, ₹ 141,514.52, ₹150,108.08, ₹ 150,751.94, ₹ 150,249.33 and ₹154,003.72, respectively, signifying that OPSDK PVA produces highest income. The extensive analysis signifies that the proposed OPSDK topology succeeds in reducing line losses by 25.62 %, 0.00 %, 37.98 %, 33.43 % and 35.49 % in comparison to SDK, FSDK, SKYSDK, MSDK and ACMS, respectively. The mismatch power losses in power output are also reduced by 643.1 W as compared to the other configurations. The OPSDK technique, thus, proves to be one of the most efficient, effective, optimised and sustainable PVA reconfiguration technique with good power savings and greater economic returns/viability.

Application of electrocoagulation process for the disposal of COD, NH3-N and turbidity from the intermediate sanitary landfill leachate

This study aims to determine the COD, NH3-N and turbidity disposal efficiencies from leachate in the Bingöl landfill and highlight the electrocoagulation (EC) process’s performance in removing these pollutants. After establishing that landfill leachate was intermediate aged, its characteristics were identified using physical, chemical and elemental analyses. Six parallel-connected electrode plates with stainless steel as the cathode and aluminium as the anode were used to construct an electrocoagulation cell. After a 40-min treatment interval, the optimal disposal efficiencies for COD and turbidity from the leachate were determined to be 87% and 62%, respectively, at pH 5. Following a 40-min reaction, BOD5 concentration and BOD5/COD ratio were determined to be 85.75 mg O2/L and 0.64, respectively, at pH 5. At a NaCl concentration of 10 mM, the optimum disposal efficiency for NH3-N was determined to be 33%. The reaction kinetics matched pseudo-first-order (PFO) kinetics due to high correlation coefficients (R2 = 0.93–0.99) in removing COD, NH3-N and turbidity under different experimental conditions. The optimal reaction rate constants were determined as 2.93 × 10−2 min−1, 1.92 × 10−2 min−1 and 7.3 × 10−3 min−1 for the disposal of COD, NH3-N and turbidity, respectively. Energy consumption, unit energy consumption and total consumption cost rose in the EC process when the current density was augmented from 15 to 25 mA/cm2.

Contrasting leaf-scale photosynthetic low-light response and its temperature dependency are key to differences in crop-scale radiation use efficiency.

Radiation use efficiency (RUE) is a key crop adaptation trait that quantifies the potential amount of aboveground biomass produced by the crop per unit of solar energy intercepted. But it is unclear why elite maize and grain sorghum hybrids differ in their RUE at the crop level. Here, we used a non-traditional top-down approach via canopy photosynthesis modelling to identify leaf-level photosynthetic traits that are key to differences in crop-level RUE. A novel photosynthetic response measurement was developed and coupled with use of a Bayesian model fitting procedure, incorporating a C4 leaf photosynthesis model, to infer cohesive sets of photosynthetic parameters by simultaneously fitting responses to CO2 , light, and temperature. Statistically significant differences between leaf photosynthetic parameters of elite maize and grain sorghum hybrids were found across a range of leaf temperatures, in particular for effects on the quantum yield of photosynthesis, but also for the maximum enzymatic activity of Rubisco and PEPc. Simulation of diurnal canopy photosynthesis predicted that the leaf-level photosynthetic low-light response and its temperature dependency are key drivers of the performance of crop-level RUE, generating testable hypotheses for further physiological analysis and bioengineering applications.

Exogenous methyl jasmonate regulates endogenous hormone synthesis of soilless cultivated Chinese chive to promote growth physiology and photosynthesis

Methyl jasmonate (MeJA) is involved in regulating various growth and development processes of plants, yet the underlying mechanisms remain unclear. Therefore, the objective of this study was to investigate the effects of exogenous MeJA on physiological growth, photosynthesis, and endogenous hormones in soilless cultivated Chinese chives. Four concentrations of MeJA (0, 300, 500, and 800 μM) were applied to the leaves of substrate-grown and hydroponics Chinese chives. The results showed that MeJA increased the leaf tissues water content and SPAD values of hydroponically Chinese chives, and 500 μM MeJA significantly enhanced the root activity and leaf carotenoids content of soilless cultivated Chinese chive, and promoted the activities of key enzymes of chlorophyll synthesis (ChlM and POR), thereby increasing chlorophyll a, chlorophyll b and total chlorophyll contents. Meanwhile, MeJA (500 μM) enhanced the activity of key enzymes in the Calvin cycle (Rubisco, FBA, FBPase, GAPDH, and TK), promoted CO2 fixation, improved photosynthetic carbon assimilation efficiency, and promoted Gs, Tr, and Pn, thereby enhancing photosynthesis. Moreover, MeJA (500 μM) significantly enhanced the instantaneous distribution (I-P) of the OJIP curve, enhanced the ability of the plastoquinone pool (PQ) to accept electrons, increased the quantum yield, promoted the apparent quantum flux per unit leaf area and energy flux ratio per unit PSII active reaction center, improved the electron transfer efficiency while reducing the heat dissipation energy flux per unit PSII active reaction center, and thus enhanced PSII activity. Additionally, exogenous MeJA (500 μM) promoted the accumulation of endogenous ZT, GA3, IAA, and ABA, but inhibited the upstream substrates for OPDA synthesis (MGDG and DGDG) in the JA synthesis pathway, and decreased the activities of JA synthases (LOX, AOC, and OPR), which in turn inhibited the synthesis of JA and MeJA. Changes in the relative content of MGDG/DGDG altered the membrane lipid composition of the photosynthetic membrane, which in turn altered the energy balance of the light reaction and improved the efficiency of electron transfer within the photosynthetic membrane, thereby enhancing the photosynthetic capacity. In conclusion, our study demonstrates that exogenous MeJA improves root activity and chlorophyll accumulation in soilless cultured Chinese chives, and adjusting the composition of photosynthetic membrane lipids by regulating the levels of endogenous hormones and JA-synthesizing substrates, promoting the efficiency of electron transfer, enhancing PSII activity, and promoting photosynthetic carbon fixation, thereby enhancing photosynthesis and promoting growth.

Responses of Soil and Ammonia Nitrogen Loss Rates to Hydraulic Parameters under Different Slope Gradients and Rainfall Intensities

Soil erosion and the consequent loss of nutrients have consistently been significant factors contributing to land degradation and nonpoint source pollution. While runoff serves as the primary carrier for nutrient loss, the hydraulic processes governing the mechanisms of nutrient loss remain not entirely clear. This paper aims to investigate the impacts of rainfall intensity and the slope gradient on hydraulic parameters, soil loss rates, and ammonia nitrogen loss rates, with the objective of determining the optimal hydraulic parameters for more accurate predictions of soil erosion and nutrient loss rates. A series of simulated rainfall experiments with three rainfall intensities (25, 50, and 75 mm min−1) and four slope gradients (8.7%, 17.6%, 26.8%, and 36.4%) were conducted on a 5 m × 10 m slope. The results indicated that the flow velocity, shear stress, stream power, unit stream power, and unit energy all increased with the increase in slope gradient or rainfall intensity. The water depth decreased with an increase in the slope gradient but increased with an increase in the rainfall intensity. Laminar flow occurred in all experiments (Reynolds number < 500). Only the overland flow under a 25 mm h−1 rainfall intensity and 8.7% slope gradient was subcritical flow (Froude number < 1). Hydraulic parameters, the soil loss rate, and ammonia nitrogen loss rate could be all expressed as the product of rainfall intensity and slope power function, with R2 ranging from 0.949 to 0.997. The average soil loss rate and process soil erosion rate could both be fitted using the power function of hydraulic parameters, with the optimal fitting parameter being stream power (R2 = 0.980 and 0.909). The average ammonia nitrogen loss rate exhibited a linear relationship with the hydraulic parameters, and the optimal fitting parameter was also stream power (R2 = 0.933). However, there were relatively low correlations between hydrodynamic parameters and the ammonia nitrogen loss rate (R2 = 0.450–0587). Our results contribute to a deeper understanding of the hydraulic processes involved in nutrient loss.

Breathing Planet Earth: Analysis of Keeling’s Data on CO2 and O2 with Respiratory Quotient (RQ), Part I: Global Respiratory Quotient (RQGlob) of Earth

In biology, respiratory quotient (RQ) is defined as the ratio of CO2 moles produced per mole of oxygen consumed. Recently, Annamalai et al. applied the RQ concept to engineering literature to show that CO2 emission in Giga Tons per Exa J of energy = 0.1 ∗ RQ. Hence, the RQ is a measure of CO2 released per unit of energy released during combustion. Power plants on earth use a mix of fossil fuels (FF), and the RQ of the mix is estimated as 0.75. Keeling’s data on CO2 and O2 concentrations in the atmosphere (abbreviated as atm., 1991–2018) are used to determine the average RQGlob of earth as 0.47, indicating that 0.47 “net” moles of CO2 are added to which means that there is a net loss of 5.6 kg C(s) from earth per mole of O2 depleted in the absence of sequestration, or the mass loss rate of earth is estimated at 4.3 GT per year. Based on recent literature on the earth’s tilt and the amount of water pumped, it is speculated that there could be an additional tilt of 2.7 cm over the next 17 years. While RQ of FF, or biomass, is a property, RQGlob is not. It is shown that the lower the RQGlob, the higher the acidity of oceans, the lesser the CO2 addition to atm, and the lower the earth’s mass loss. Keeling’s saw-tooth pattern of O2 is predicted from known CO2 data and RQGlob. In Part II, the RQ concept is expanded to define energy-based RQGlob,En, and adopt the CO2 and O2 balance equations, which are then used in developing the explicit relations for CO2 distribution amongst atm., land, and ocean, and the RQ-based results are validated with results from more detailed literature models for the period 1991–2018.

A novel cryogenic air separation unit with energy storage: Recovering waste heat and reusing storage media

The combination of the air separation unit and cryogenic energy storage enhances system efficiency; however, there are still significant irreversible losses in the energy conversion process and high investment costs. This paper explored the potential for deep integration of these two process and proposed a novel air separation with liquid nitrogen energy storage process recovering waste heat and reusing storage media process. The proposed process improved the liquefaction and power generation processes and recovered the compression heat for air purification processes. Taking an actual plant as a research case, the integrated system was simulated using Aspen Plus software. The round-trip efficiency, exergy efficiency, and power generation of the proposed process are 0.537, 0.722, and 10.52 MWh respectively, which are 6.2 %, 20.9 %, and 68.3 % higher than those of conventional process. By reusing storage nitrogen and recovering compression heat, the proposed process reduces the initial investment cost by half while achieving a dynamic payback period of 6 years with a levelized cost of electricity at $82.8/MWh. Furthermore, it is worth noting that media reuse operations have a greater impact on economy when off-peak electricity cost is low; whereas utilization of compression heat has a greater impact when off-peak electricity cost is high.

Potential exportation of wood pellets and torrefied biomass pellets logistics cost analysis: A comparative case study from Portugal

<abstract> <p>This study evaluates the logistics cost associated with transporting Wood Pellets (WP) and Torrefied Biomass Pellets (TBP) from Aveiro, Portugal's principal WP exporting port, to Northern European destinations. With increasing emphasis on sustainable energy, understanding the cost dynamics between WP and TBP becomes crucial for market competitiveness. Using data sourced from the Argus Biomass Markets report, we compared the energy in gigajoules per ton of both WP and TBP. Torrefaction results in pellets with superior energy and bulk densities, influencing their transportation logistics costs. The main metrics for comparison were cost per energy unit and the implications of energy and bulk densities on transport costs. Preliminary findings indicate that although torrefied pellets undergo more significant mass loss than energy loss, their enhanced energy and bulk densities present logistical advantages. These advantages manifest as more tons per volume unit and heightened energy per ton, which ultimately lead to reduced transportation cost per energy unit. The insights from this analysis provide valuable input for the biofuel sector. By understanding the cost benefits associated with TBP transportation in contrast to WP, stakeholders can make strategic decisions, bolstering the competitiveness of Portuguese biofuel products in the European domain.</p> </abstract>

Econometric modeling of carbon price impacts on the bidding mechanism between different energy sources in the electricity market

Abstract Virtual power plants (VPPs) can aggregate different energy sources into a whole to participate in the electricity market and carbon trading market, and as the scale of VPPs continues to expand, they will also be transformed from the original price takers to price makers. The paper considers VPP as a price setter and suggests a two-tier bidding strategy for the VPP day-ahead electricity market that incorporates the impact of the carbon price. Among them, the upper-layer model aims to maximize the expected revenue of VPP, while the lower-layer model aims to minimize the system clearing cost. The dynamic carbon emission factor is used in the strategy to create a market incentive factor that corrects the offer price of each unit before clearing it again. Finally, the optimal bidding strategy, as well as the operation plan of the VPP, are given through an arithmetic example, and the impact of the uncertainty in the wind farm output forecast in the VPP on the expected return of the VPP is analyzed. The impact of carbon prices on power prices, output, and rates of energy demand change are further explored to provide a basis for the compensation mechanism for ecological protection of carbon values. The arithmetic example shows that VPP can influence the market price through strategic bidding decisions, and after considering the carbon price, the power market clearing price is 4.46 yuan/MWh, and the maximum gain is obtained as 225.54. The consumption rate of new energy units such as WT and PV is increased, the carbon emissions are reduced, and the total gain of VPP is increased. The increase in carbon prices and the offer of traditional generators increase the amount of electricity cleared by renewable energy units, while the increase in carbon quota ratio and the offer of new energy generators increase the average clearing price.

Designing a biodiversity credit accounting framework for environmental investment and financing

<p>Achieving biodiversity goals and targets poses a significant financial challenge due to biodiversity externalities. Efforts to address this challenge have focused on market-based solutions for biodiversity offsets to bridge the financial gap. However, accurately calculating biodiversity credits remains a barrier to promoting and implementing these solutions. Here, we propose an innovative accounting framework for biodiversity credits based on the emergy accounting approach. Emergy (spelled with an m) represents the biosphere work performed over time and space (ecosystem services) that supports species, human societies and economies, and is measured in units of solar equivalent energy (emergy, sej). This unified accounting method considers the perspectives of ecosystem productivity, ecosystem networks, and human well-being. We evaluated the biodiversity credits in 157 restoration projects and found several advantages in terms of differentiating project types and setting thresholds for biodiversity credit increases in restoration projects. Only 66% of the projects achieved biodiversity credit increases, and only 29% of the generated credit can be traded on the market. This study provides a scientific foundation for decision-making in ecosystem restoration management and contributes to broader biodiversity conservation solutions as well as to bridging the financial gap in achieving biodiversity goals.</p>

Synthesis and performance evaluation of zinc oxide tubes/alginate microfibre composites for photodegradation of methylene blue: a novel reporting approach.

This research investigates the efficacy of zinc oxide (ZnO) tubes in decontaminating polluted water using a substrate-free hydrothermal synthesis process for ZnO tubes. The synthesized tubes are impregnated into calcium alginate microfibres, strategically chosen for their high surface area to enhance photocatalytic degradation performance and for practical handling during decontamination and subsequent collection, thereby preventing secondary contamination. Structural and morphological analyses, conducted using Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD), thoroughly characterize the properties of the ZnO tubes and the composite material. The efficacy of this composite is demonstrated through the photocatalytic degradation of methylene blue (MB), as a representative organic pollutant, resulting in an 88% degradation of MB after 5 hours of irradiation by a sun simulator. Cyclic tests exhibit consistent degradation levels in the first four cycles (81-89%), followed by a subsequent decrease to 72% in the fifth cycle, coinciding with the breakdown of the microfibres into shorter fragments. Innovatively, this study introduces an approach to reporting photocatalytic degradation results, utilizing normalized pollutant concentration plotted against irradiated energy instead of time, as energy encompasses irradiated power, time, and surface area. This reveals that the 88% degradation of MB is achieved by irradiating the sample with an approximately 18 kJ. Additionally, a new metric, Specific Energy Efficiency (SEE), is introduced. It expresses the ratio of degraded pollutant mass to the mass of photocatalytic active material per unit of irradiated energy, with the maximum and cumulative SEE in this study being 1.044 μg g-1 J-1 and 326 ng g-1 J-1, respectively. This research not only contributes to the understanding of ZnO tubes' efficiency in polluted water decontamination but also introduces valuable insights for standardized reporting in photocatalytic degradation studies.

Food Portion Size Estimation for Developing a Healthy Eating Index: Influence of Unit Count and Energy Density

Estimating food consumption is often influenced by the intricate cognitive processes involved in determining portion sizes. Understanding the factors influencing these processes can enhance the accuracy of dietary assessments. This study aims to evaluate the ability of participants to estimate portion sizes of common foods and to identify estimation errors. Methods: This study used a cross-sectional approach involving 35 participants, who estimated the portions of various foods, measured in grams or milliliters, based on memory. The magnitude and direction of estimation errors were analyzed. Underestimation was defined as estimated quantities (EQ) less than 90% of the actual weighed quantity (WQ), while overestimation was defined as EQ greater than 110% of the WQ. Results: Only 15.59% of the estimates were considered accurate (approximately 10% of the actual weight). Animal proteins, vegetables, and sugars were the most frequently underestimated, while staple foods, vegetable proteins, fruits, vegetables, and fats/oils were the most commonly overestimated. Conclusion: This study revealed a low proportion of accurate food portion size estimates, with a tendency to overestimate low-energy foods and underestimate high-energy foods.

Energy Consumption and Unit Process Emissions in Laser Removal of Diamond-like Coatings from Tooling

Laser cleaning technology is a promising technology for selective removal of coatings from substrates to facilitate re-use and recoating. A leading coating of interest for reduced friction and operating forces is Diamond like Carbon (DLC) coating. This paper reports on the energy requirements and associated unit process scope 2 emissions for the DLC laser removal process to facilitate re-use of tooling in a circular economy. This work can assist in providing a greater understanding of the energy requirements and of energy consumption and emissions reduction strategies for the DLC removal process. This is important for the transition to net-zero emissions in manufacturing.

A Study on the Influence Factors of Agricultural Carbon Emissions in Hunan Province Based on Random Forest Model

Agricultural carbon reduction contributes to the realization of “carbon peak and carbon neutrality” strategy. This article analyzes the previous years’ data of agricultural carbon emissions in Hunan Province, and obtains the variation of carbon emissions; Using the random forest method to analyze the influence factors of agricultural carbon emissions in Hunan Province, it is proven that unit crop production value, unit energy carbon emissions in agriculture, and unit agricultural GDP energy consumption are the three most critical factors affecting agricultural carbon emissions in Hunan Province. LDMI method is used for validation. Sensitivity analysis was conducted on factors such as agricultural energy consumption, total production value of AFAF(Agriculture, forestry, animal husbandry, and fishing), total agricultural production value, crop yield, crop planting area, and non-urban population. The first five changes have a positive impact on agricultural carbon emissions, while non-urban population has a downward and then upward trend.