Hasil untuk "Energy conservation"

Khurram Shehzad, Yuanguo Xu, Sarmad Ali et al.

Herein, waste orange peel (OP) biomass residues were upcycled with iron oxide (Fe2O3) and calcination, and assessed for their adsorption efficiency for arsenite (As(III)) using a series of batch adsorption experiments that took into account different operational parameters, including contact time, starting concentration of arsenite, starting pH, and the impact of other ions in the solution. In addition, optimization of As(III) removal by OPFC was achieved by the use of RSM and BBD analysis. The OPFC exhibited an As(III) adsorption capacity of 23.6 mg/g at neutral pH, superior to many reported adsorbents, attributed to its high surface area (81.47 m2/g), pore volume (0.18 cm3/g), pore radius (21.14 nm), and abundant surface-active sites. Adsorption equilibrium data conformed to the Freundlich model, while the kinetic data were best described by the pseudo-second-order model. The OPFC also demonstrated strong resistance to coexisting ions, excellent regeneration-ability, and high efficacy in treating simulated As(III)-contaminated water. In addition, response surface methodology (RSM) with Box Behnken Design (BBD) optimization demonstrated that at pH 5.25, with 500 μg/L of initial As(III) concentration, OPFC could reach to a maximum adsorption capacity of 472.38 μg/g in 720 min. These results indicate OPFC's strong potential as a sustainable mesoporous adsorbent for practical As(III) remediation.

Hanuman Sahay Jat, Kailash Prajapat, Shivani Khokhar et al.

Intensive rice-based systems in the Indo-Gangetic Plain of India face critical sustainability challenges, including high energy use, excessive greenhouse gas (GHG) emissions, and unsustainable groundwater exploitation. This study evaluates productivity and environmental footprints (energy, water, and carbon) to foster environmental stewardship through conservation agriculture-based climate-smart agriculture practices (CSAPs). Six scenarios (Sc) were analyzed: conventional till (CT) rice-wheat (CT-RW, Sc 1); CT rice-zero till (ZT) wheat-ZT mungbean (CTR-ZTWM, Sc 2); ZT direct-seeded rice-ZTWM (ZTRWM, Sc 3); ZT maize-ZTWM (ZTMWM, Sc 4); Sc 3 with subsurface drip (SSD) irrigation (ZTRWM-SSD, Sc 5); and Sc 4 with SSD (ZTMWM-SSD, Sc 6). The CSAPs (Sc 3-Sc 6) outperformed Sc 1 with respect to key performance parameters. Sc 6 (ZTMWM-SSD) achieved the maximum rice equivalent yield (8.25 t ha⁻¹), a 22.2 % increase over Sc 1. Wheat yield in Sc 6 reached to 6.34 t ha⁻¹, corresponding to a 22.1 % enhancement compared to Sc 1, resulting in a total system yield of 16.73 t ha⁻¹, representing a 35.6 % increase over Sc 1. For system-wide partial factor productivity of N, Sc 5 showed 51.4 % improvement, while Sc 6 achieved the highest increase of 69.7 %, reflecting significant gains in nitrogen use efficiency. The CSAPs scenarios markedly improved system water productivity, resulting in a decreased water footprint, which was lowest in Sc 6 (189 L kg⁻¹) compared to Sc 1 (1642 L kg⁻¹). Energy dynamics revealed that Sc 6 was the most efficient among all the scenarios. With an energy input of 30,360 MJ ha⁻¹, it produced energy output of 471,633 MJ ha⁻¹, and recorded the highest energy use efficiency (15.69). In terms of environmental sustainability, CSAPs (Sc 3, Sc 4, Sc 5 and Sc 6) exhibited lower system net global warming potential (GWPn), compared to CT-based scenarios (Sc 1 and Sc 2), reflecting a significantly reduced carbon footprint. These results highlight the potential of CSAPs to enhance productivity and profitability while minimizing environmental impacts, making CSAPs critical to the future of sustainable agriculture in North-western India.

J. Jacob Levenson, J. Jacob Levenson, Robert Cooper et al.

Although sea turtles are well-studied charismatic marine species, little is known about the juvenile stage, especially the oceanic phase between hatching on their natal beaches and their adult lives. To collect data on these “lost years,” six juvenile green turtles were equipped with satellite tags, released from southwestern Dominica in the eastern Caribbean, and tracked for up to 3 months. Mapping turtle movement to ocean currents reveals that juvenile green turtles spent most of their travel time within the Caribbean Sea, passively riding the prevailing currents before actively directing themselves toward distant coastal waters. Half of the tagged turtles traveled to coastal foraging grounds off of Colombia and Venezuela, while one traveled north past Puerto Rico. These findings provide novel data for the movements of juvenile green turtles hatched in the Eastern Caribbean region.

Shuheng Zhang, Haiying Cao, Shan Xu et al.

Natural Hard Crust (NHC) with a certain thickness in the North China Plain may be used as an embankment’s bearing layer. However, the mechanical responses of pavements with NHC are not fully understood under cyclic loading. To solve this problem, an accelerated laboratory loading test on the pavements model was conducted to estimate their stress-strain-resilient modulus behaviors. This paper describes the test procedure followed and results obtained on the Soft Soil Layer (SSL) covered with NHC considering vehicle weight, vehicle speed, thickness of NHC, and Compression Modulus Ratio of NHC to SSL (CMR). The results show that vehicle weight is the precondition for the occurrence of strain hardening or strain softening in pavements with NHC. In contrast, vehicle speeds have little effect on the mechanical response of pavements. CMR and the ratio of NHC’s thickness to embankment height are the two important factors to control the plastic deformation of pavements with NHC. The accumulated responses of pavements with NHC can be described by the shakedown approach. It is desirable to consider the direct usage of NHC as a bearing layer without any foundation treatment when CMR is greater than 3.37 and the ratio of NHC’s thickness to embankment height is higher than 2. The magnitude of NHC’s load spreading effect plays an important role in the acceleration or retardation of stress dissipation in SSL layer at different stress states, which may cause the enhancement of strain hardening or strain softening effect in SSL layer.

Rosemary E. Alden, Huangjie Gong, Tim Rooney et al.

As the smart grid involves more new technologies such as electric vehicles (EVs) and distributed energy resources (DERs), more attention is needed in research to general energy storage (GES) based energy management systems (EMS) that account for all possible load shifting and control strategies, specifically with major appliances that are projected to continue electrification such as the electric water heater (EWH). In this work, a methodology for a modified single-node model of a resistive EWH is proposed with improved internal tank temperature for user comfort modeling and capabilities for conservation voltage reduction (CVR) simulations as well as Energy Star and Consumer Technology Association communications protocol (CTA-2045) compliant controls, including energy storage calculations for “energy take”. Daily and weekly simulations are performed on a representative IEEE test feeder distribution system with experimental load and hot water draw (HWD) profiles to consider user comfort. Sequential controls are developed to reduce power spikes from controls and lead to peak shavings. It is found that EWHs are suitable for virtual power plant (VPP) operation with sustainable tank temperatures, i.e., average water temperature is maintained at set-point or above at the end of the control period while shifting up to 78% of EWH energy out of shed windows per day and 75% over a week, which amounts to up to 23% of the total load shifted on the example power system. While CVR simulations reduced the peak power of individual EWHs, the aggregation effect at the distribution level negates this reduction in power for the community. The EWH is shown as an energy constant load without consistent benefit from CVR across the example community with low energy reductions of less than 0.1% and, in some cases, increased daily energy by 0.18%.

Nidhya Rathinavel, Kavikumaran Kannadasan, Abdul Aleem Mohamed Ismail et al.

Adopting proper waste management technology in the place of the construction industry to the extent possible to lower the production of new materials and intern reduces the environmental impact pertaining to the industry. In this work, eggshell powder (ESP; waste from the poultry industry) and fly ash (FA; waste from combustion of coal) were utilized as precursors for producing geopolymer and to substitute conventional cement-based construction materials. Three different weight percentage ratios of precursors, namely, 90FA:10ESP, 80FA:20ESP, and 70FA:30ESP were reinforced with two different weight percentages, namely, 15 and 30 wt% of paddy straw in the presence of suitable combinations of sodium silicate and sodium hydroxide to obtain lightweight geopolymer panels. Results received from different analytical tests, namely, density, water absorption, compressive strength, and flexural strength infer that the incorporation of ESP enhances the performance of the geopolymer products to a considerable extent. The specimen sample made using 70FA:30ESP in the absence of paddy straw reinforcement possesses a compressive strength value of 15.64 MPa, which is higher than that of paddy straw reinforced panels. It was observed that there was a reverse trend noticed in the case of flexural behavior on reinforcement of paddy straw, namely, 15 wt% possesses a higher value than that of the panel (70FA:30ESP) made using in the absence of reinforcement. The lowest thermal conductivity value was observed at 0.0633 W/m·K for the sample 90FA:10ESP reinforced with 30% paddy straw. Data from different studies infer that using ESP and paddy straw reinforcement influences strength properties and thermal conductivity. The present study indicates valid information related to the using biowastes for the production of insulation materials and environmental preservation and energy conservation.

Zhengyuan Liu, Zhengyuan Liu, Johnny F. I. Lam et al.

Green investment can promote the low-carbon development of energy consumption structure in direct and indirect ways through financial support for new energy industry and pulling effect on environmental protection industry, which is of great significance to the sustainable development of economy and society. Through empirical analysis of the panel data of provinces and municipalities in China, this paper finds that the impact of green investment on the energy consumption structure is highly differentiated between regions: the development of green investment in the eastern region will inhibit the increase of the proportion of coal and other polluting energy sources in the energy consumption structure, which will help the energy consumption structure tend to develop in a decarbonized way; in the central region, the impact of green investment on the energy consumption structure is insignificant; and in the western region, green investment instead promotes the development of the energy consumption structure in a decarbonized way. In the western region, green investment instead promotes the proportion of coal and other polluting energy in the energy consumption structure. The main reason for this is that there are big differences in the level of economic development, characteristics of industrial structure, population size and technological level between the East, the Middle East and the West. It is an important measure to strengthen green investment and improve energy consumption structure to dynamically adjust green development goals, strengthen financial support for energy conservation and environmental protection industries, and narrow the regional development gap in all directions.

Emily L. Hague, Carol E. Sparling, Ceri Morris et al.

Marine mammals are vulnerable to a variety of acute and chronic anthropogenic stressors, potentially experiencing these in isolation, successively and/or simultaneously. Formal assessment of the likely impact(s) of the cumulative effects of multiple stressors on a defined population is carried out through a Cumulative Effects Assessment (CEA), which is a mandatory component of the Environmental Impact Assessment (EIA) process in many countries. However, for marine mammals, the information required to feed into CEA, such as thresholds for disturbance, frequency of multiple (and simultaneous) exposures, interactions between stressors, and individual variation in response, is extremely limited, though our understanding is slowly improving. The gaps in knowledge make it challenging to effectively quantify and subsequently assess the risk of individual and population consequences of multiple disturbances in the form of a CEA. To assess the current state of practice for assessing cumulative effects on marine mammals within UK waters, 93 CEAs were reviewed across eleven maritime industries. An objective framework of thirteen evaluative criteria was used to score each assessment on a scale of 13-52 (weak - strong). Scores varied significantly by industry. On average, the aquaculture industry produced the lowest scoring CEAs, whilst the large offshore windfarm industry (≥ 20 turbines) scored highest, according to the scoring criteria used. There was a significant increase in scores over the sample period (2009-2019), though this was mostly attributed to five industries (cable, large and small offshore wind farms, tidal and wave energy). There was inconsistency in the language used to define and describe cumulative effects and a lack of routinely applied methodology. We use the findings presented here, along with a wider review of the literature, to provide recommendations and discussion points aimed at supporting the standardisation and improvement of CEA practice. Although this research focused on how marine mammals were considered within UK CEAs, recommendations made are broadly applicable to assessments conducted for other receptors, countries and/or environments. Adoption of these proposals would help to ensure a more consistent approach, and would aid decision-makers and practitioners in mitigating any potential impacts, to ensure conservation objectives of marine mammal populations are not compromised.

Lin Yu, Huadong Sun, Shiyun Xu et al.

Nir Regev, Dov Wulich

Human presence detection is an application that has a growing need in many industries. Hotel room occupancy is critical for electricity and energy conservation. Industrial factories and plants have the same need to know the occupancy status to regulate electricity, lighting, and energy expenditures. In home security there is an obvious necessity to detect human presence inside the residence. For elderly care and healthcare, the system would like to know if the person is sleeping in the room, sitting on a sofa or conversely, is not present. This paper focuses on the problem of detecting presence using only the minute movements of breathing while at the same time estimating the breathing rate, which is the secondary aim of the paper. We extract the suspected breathing signal, and construct its Fourier series (FS) equivalent. Then we employ a generalized likelihood ratio test (GLRT) on the FS signal to determine if it is a breathing pattern or noise. We will show that calculating the GLRT also yields the maximum likelihood (ML) estimator for the breathing rate. We tested this algorithm on sleeping babies as well as conducted experiments on humans aged 12 to 44 sitting on a chair in front of the radar. The results are reported in the sequel.

N.S. Prinith, J.G. Manjunatha

The two promising electrochemical sensor constructed using carbon paste electrode modified with Octyl phenol ethoxylate surfactant (OPEMCPE) and carbon paste electrode modified with Sodium lauryl sulfate (SLSMCPE). The electrochemical characterization of Anthrone (ANT) was studied at the surface of OPEMCPE with supporting electrolyte of pH 7.0 in 0.1 M phosphate buffer (PBS) and also at the surface of SLSMCPE with supporting electrolyte of pH 7.5 in 0.1 M PBS by using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The OPEMCPE and SLSMCPE exhibited an efficient electrocatalytic activity towards ANT than the bare carbon paste electrode (BCPE). The characterization of both the electrodes are done by FE-SEM and EDX for SLSMCPE. The detection limit and limit of quantification of ANT employed in CV at the surface of OPEMCPE were 18.8 × 10−7 M and 6.27 × 10−6 M and at the surface of SLSMCPE were 10.6 × 10−7 M and 3.53 × 10−6 M. Moreover, tailored electrode offers high sensitivity, highly stable, good conductivity, transducing, biocompatibility, reliable to resistant electrode fouling and good reproducibility. Keywords: Carbon paste electrode, Octyl phenol ethoxylate, Sodium lauryl sulfate, Anthrone, Electrochemical sensor, Cyclic voltammetry

Rocco Tiberti, Francesco Buscaglia, Marco Armodi et al.

Mountain lakes provide some fundamental ecosystem services (i.e., water supply for drinking and energy production) and have an enormous aesthetic and conservation value. Ecological knowledge on mountain lakes, however, is still scarce and limited to a few geographical areas and mainly to abiotic features. To fill this gap, a limnological campaign was carried out on 19 lakes of the Mont Avic Natural Park (Aosta, Western Italian Alps). Bathymetric maps of the lakes are provided in this paper, as is data on the lakes’ physical properties, chemistry, nano- and pico-plankton, zooplankton, littoral macroinvertebrates, amphibians and introduced fish. The aim of this study was to create a reference database of ecological data for the development of new studies and conservation measures/actions. To this end, ecological data are discussed from both a limnological and a conservation perspective, allowing for the identification of major threats affecting the lakes in the protected area. Despite local threats which include water exploitation, organic pollution, and introduced fish, water quality was good. Lake biota can however be affected by such threats, in particular introduced fish (Salmonidae and Cyprinidae), representing a challenging conservation problem.

Yaşar Demirel

Shiying MA, Qing WANG

Large-scale centralized new energy sending system is a unique form of power grid in China. Due to the high proportion of new energy sources and low tolerance to high-voltage direct current(HVDC) fault disturbance, there are prominent problems in the coordination between source and power network. The major potential risks, such as large voltage fluctuation, large frequency fluctuation and low frequency oscillation were analyzed. It was pointed out that the key problems of modeling include the auxiliary control of excitation system, generator protection concerned with network and generator speed control with dynamic system. The simulation evaluation process and precautions of the source network coordination in large-scale centralized new energy sending system were also proposed, which could be a reference for the actual simulation evaluation operation.

Mariusz Radtke, Anna Ignaszak

Abstract In this study, we optimized the dispersion of hydrophobic carbons within ionically conductive hydrogels composed of a poly (acrylamide)-pAAm/poly (N,N-methylenebisacrylamide)-pMBAA modified with Nafion 117®. The carbon-embedded hydrogel films were prepared by in situ UV polymerization of aqueous suspension containing KCl, acrylamide and N,N-methylenebisacrylamide monomers, the multi-walled-carbon nanotubes, graphene, single-walled carbon nanohorns, and their composites with polypyrrole. These electrodes were translucent, stretchable, ionically and electronically conductive at low carbon content. In addition, they were very flexible, reaching a stretch up to 1475.57% of their initial length. Mechanical characteristics and conductivity were measured at their maximum hydration, corresponding to water uptake of 47.20% after 5 days of curing in humidity chamber. Hydrogels with dispersed carbon demonstrated both ionic and electronic conductivity in hydrated state and electronic conductivity alone when the electrode was dry. Nafion 117® acted as a surfactant and played a significant role in the improvement of carbon distribution within the hydrogel due to the hydrophobic–hydrophilic interaction between hydrogel, Nafion and the carbon. This was further correlated with changes in zeta potential at the carbon–hydrogel interface upon addition of Nafion, measured using a rotating disk electrode voltammetry. Graphical abstract

Xiangxin Li, Ming Zhou, Yazhou Luo et al.

In order to satisfy demands for DC de-icing of optical fiber composite overhead ground wire (OPGW) and solve questions such as those relating to circulating current loss and liability of suffering from lightning strike, the grounding method of OPGW must be changed from the current commonly used method of being grounded at every tower to being grounded at one tower. The OPGW would be connected to the tower by an insulator, which is often shunt connected with a protective discharge clearance. The recommended value of the discharge clearance is from 70 to 80 mm. The lightning impulse discharge voltage of such a clearance is generally not more than 100 kV. However, as the transmission line is struck by lightning, over-voltage on the clearance is 885 kV at least, even up to a few MV. The clearance can be broken down reliably. The influence of insulation reconstruction for OPGW on the induced current and the power loss of the AC transmission line was studied by means of theoretical analysis and simulation calculations. Results indicate that change of the OPGW grounding mode could reduce the induced current of the ground wire to below 1 A and reduce the power loss of the line to below 1 W/km. Power loss could be reduced by over 99%. Adoption of a suitable grounding mode for OPGW is of great significance for DC de-icing, lightning protection safety, and energy savings for UHV projects.

Mohammad Tariq, Vinod Kumar Nema

A program has been developed to calculate enthalpies at the salient points (later referred to as stations) of a combined power and cooling cycle provided pressure, temperature, mixture concentration and condition are known at these points. The ammonia-water mixture, which is taken as the working fluid, may be at one of the following seven conditions namely, superheated vapour mixture, mixture of superheated component of ammonia and pseudo vapour component of water, saturated vapour mixture, wet vapour mixture, saturated liquid mixture, mixture of subcooled water and pseudo liquid ammonia and subcooled mixture of subcooled components of ammonia and water. The mixture boiling-point temperature and dew-point temperature, needed to establish the condition of the working fluid, are functions of absolute pressure, critical pressure and critical temperature of the mixture; later two depend on the mixture concentration and the corresponding critical values of water at the given station. Using typical values of the variables as listed above, enthalpies at all stations are predicted. The predicted enthalpies are close (within 3%) to those available in the literature except at two stations where the mixture was weak in ammonia and its temperature was either in the near vicinity of the mixture boiling-point temperature or below the saturation temperature of pure ammonia at the concerned pressure. Using the predicted values of enthalpies, thermal efficiency of the combined power and cooling cycle has been calculated.

Peter Lowdon, Kelly Yu-Ju Chiu, Stanley J. Brodsky

The structure of the matrix elements of the energy–momentum tensor play an important role in determining the properties of the form factors A(q2), B(q2) and C(q2) which appear in the Lorentz covariant decomposition of the matrix elements. In this paper we apply a rigorous frame-independent distributional-matching approach to the matrix elements of the Poincaré generators in order to derive constraints on these form factors as q→0. In contrast to the literature, we explicitly demonstrate that the vanishing of the anomalous gravitomagnetic moment B(0) and the condition A(0)=1 are independent of one another, and that these constraints are not related to the specific properties or conservation of the individual Poincaré generators themselves, but are in fact a consequence of the physical on-shell requirement of the states in the matrix elements and the manner in which these states transform under Poincaré transformations.

Isamu Matsukawa

Seung-Hwan Yang, Jung-Eek Son, Sang-Deok Lee et al.

If a greenhouse in the temperate and subtropical regions is maintained in a closed condition, the indoor temperature commonly exceeds that required for optimal plant growth, even in the cold season. This study considered this excess energy as surplus thermal energy (STE), which can be recovered, stored and used when heating is necessary. To use the STE economically and effectively, the amount of STE must be estimated before designing a utilization system. Therefore, this study proposed an STE model using energy balance equations for the three steps of the STE generation process. The coefficients in the model were determined by the results of previous research and experiments using the test greenhouse. The proposed STE model produced monthly errors of 17.9%, 10.4% and 7.4% for December, January and February, respectively. Furthermore, the effects of the coefficients on the model accuracy were revealed by the estimation error assessment and linear regression analysis through fixing dynamic coefficients. A sensitivity analysis of the model coefficients indicated that the coefficients have to be determined carefully. This study also provides effective ways to increase the amount of STE.