Efficiency Of Use Research Articles

Highly selective electrocatalytic alkynol semi-hydrogenation for continuous production of alkenols

Alkynols semi-hydrogenation is a critical industrial process as the product, alkenols, have extensive applications in chemistry and life sciences. However, this class of reactions is plagued by the use of high-pressure hydrogen, Pd-based catalysts, and low efficiency of the contemporary thermocatalytic process. Here, we report an electrocatalytic approach for selectively hydrogenating alkynols to alkenols under ambient conditions. For representative 2-methyl-3-butene-2-ol, Cu nanoarrays derived electrochemically from CuO, achieve a high partial current density of 750 mA cm−2 and specific selectivity of 97% at −0.88 V vs. reversible hydrogen electrode in alkaline solution. Even in a large two-electrode flow electrolyser, the Cu nanoarrays deliver a single-pass alkynol conversion of 93% with continuous production of 2-methyl-3-butene-2-ol at a rate of ~169 g gCu−1 h−1. Theoretical and in situ electrochemical infrared investigations reveal that the semi-hydrogenation performance is enhanced by exothermic alkynol adsorption and alkenol desorption on the Cu surfaces. Furthermore, this electrocatalytic semi-hydrogenation strategy is shown to be applicable to a variety of alkynol substrates.

The Impact of Migration on Farm Performance: Evidence from Rice Farmers in China

Developing economies face challenges in improving the overall performance of farms. An essential challenge could be a substantial shift in the agricultural labor force to off-farm sectors during the process of economic transition. This paper estimates the causal impact of migration on the economic and environmental performance of rice farms, measured using technical efficiency and fertilizer use efficiency. A stochastic frontier analysis, based on the survey data collected in four regions of China, is applied, finding an average technical efficiency of 0.92, while the average fertilizer use efficiency is only 0.22. The results of propensity score matching suggest that migration has a marginally negative impact on both technical efficiency and fertilizer use efficiency of their rice production, while the impact is amplified for farmers who participated in migration more intensively. This would imply that the government policy on the migration of rural households might also need to consider this impact.

Examining the Effects of a Real-Time, Knowledge-Aware Tool for Academic Writing Assessment

The computer-supported writing assessment (CSWA) has been widely used to reduce instructor workload and provide real-time feedback. Interpretability of CSWA draws extensive attention because it can benefit the validity, transparency, and knowledge-aware feedback of academic writing assessments. This study proposes a novel assessment tool, EduNERScore, which enables raters to identify different types of domain knowledge from unstructured educational texts and strengthen the interpretation of assessment through knowledge-aware evidence. This research uses an educational experiment to examine raters’ validity, efficiency, interpretability and user perception with and without the support of EduNERScore. The findings show that the experimental group with the support of EduNERScore achieves human-expert validity, high efficiency, interpretability and good use perception, compared with the control group. Finally, based on the empirical results, this research discusses the technological and educational implications for developing and applying the interpretable CSWA system in education.

Energy efficiency in industrial environments: an updated review and a new research agenda

Nowadays, discussions about the use of energy efficiency in industries have intensified due to the need to optimize the resources used, especially the high cost in the production process. In this context, a literature review and a research agenda on energy efficiency in industrial environments can assist in the search for solutions and challenges to reduce energy consumption in manufacturing, as well as identify future trends for the topic. Therefore, this article proposes to update the energy efficiency research agenda in industrial environments, through a systematic review of the literature, between the years 2015 and 2020, in search of articles published in journals with current practices and the new strategies used in energy management. For the review of the research agenda, one hundred and eighty-five articles were selected, which were read and used in the bibliometric analysis, which was compared to the results obtained and observed in the base article for this update, thus helping in directing the creation of an agenda for studies and practices in energy efficiency in manufacturing environments.

Dietary, locomotory, and metabolic reactions of Abax parallelus (Coleoptera, Carabidae) to acute thiamethoxam intoxication.

Carabids (Coleoptera: Carabidae) are abundant predators in ecosystems and serve as pest biocontrol in agroecosystems and forestry. Here we test the impact of thiamethoxam, among the most used neonicotinoids on the consumption rate, locomotion, metabolomics, and oxidative stress level measuring superoxide dismutase (SOD) activity in a predatory carabid, Abax parallelus (Duftschmid, 1812), after acute exposure in the laboratory trials, to get additional data that might link the use of pesticides and predation efficiency. Beetles were exposed to increasing concentrations of thiamethoxam by dipping method, and left to feed overnight prior to the assays. The results showed that individuals treated with higher concentrations of thiamethoxam (20 and 40 mg/L) consumed significantly less food per body weight and had a higher share of intoxicated and moribund individuals. The mass of consumed food per beetle body weight and observed locomotion did not differ significantly between control and groups treated with lower concentrations of thiamethoxam. There are significant differences in concentrations of some metabolites between treated and control individuals, primary in succinate and d-glucose, indicating a disruption in energy production. On the other hand, there is no statistically significant differences in SOD activity among the groups. To conclude, acute exposure to thiamethoxam can result in negative sub-lethal effects in predatory activity and energy budget, while the effects of long-term exposure to lower doses require further research, as well as field assessment on the predation efficiency after pesticide application.

Method for studying water removal and air penetration during through air drying of tissue in laboratory scale

Energy use, together with consumption of raw materials, machine clothing, and wet end chemicals, are some of the most critical aspects in successful tissue making today. This work was aimed at developing a laboratory-scale method of estimating dewatering mechanisms, vacuum efficiency, and energy use of Through Air Drying (TAD) of tissue. When compared to pilot data, the results of the new laboratory method for investigating dewatering during TAD were in the same magnitude, around 24 to 26% dryness after vacuum dewatering, and 27 to 29% dryness after TAD molding. Sheet properties, such as caliper and surface profile, were evaluated and compared to commercial tissue sheets. The results indicate that it will be possible to precisely measure accurate dryness development and penetrated air volume for tissue sheet forming and TAD molding at a laboratory scale. This can contribute to the efforts of implementing a circular forest-based bioeconomy by increasing the fundamental understanding of dewatering of tissue paper materials, which is facilitated by improvements in energy use. The new method developed in this work will make it easier to assess ideas that are difficult to bring to pilot scale or full scale before learning more of the dewatering capabilities. The authors are convinced that improved knowledge of tissue dewatering mechanisms, forming, and material transport during and after TAD dewatering can increase the efficiency of the industrial manufacturing processes.

SODAS: Smart Open Data as a Service for Improving Interconnectivity and Data Usability

In this study, we proposed Smart Open Data as a Service (SODAS) as a new open data platform based on the international standards Data Catalog Vocabulary (DCAT) and Comprehensive Knowledge Archive Network (CKAN) to facilitate the release and sharing of data. We first analyze the five problems in the legacy CKAN and then draw up corresponding solutions through three core strategies: CKAN expansion, DCATv2 support, and extendable DataMap. We then define four components and nine function blocks of SODAS for each core strategy. As a result, SODAS drives Open Data Portal, Open Data Reference Model, DataMap Publisher, and Analytics and Development Environment (ADE) Provisioning for connecting the defined function blocks. We confirm that each function works correctly through the SODAS Web portal, and then we apply SODAS to actual data distribution sites to prove its efficiency and practical use. SODAS is the first open data platform that provides secure interoperability between heterogeneous platforms based on international standards, and it enables domain-free data management with flexible metadata.

Research on the impact of technical progress on the carbon productivity in China’s service industry

The energy consumption and carbon emission of the service industry should not be ignored. In order to achieve green and low-carbon development, improving the carbon productivity of the service industry is an extremely important method, and technical progress is a key path to improving the carbon productivity of the service industry. This paper decomposes the technical progress of China’s service industry into technical progress of non-energy factors and technical progress of energy factor, and analyzes the impact and action mechanism of these two technical progress on the carbon productivity of China’s service industry respectively from the theoretical and empirical perspectives. The main conclusions of this paper are as follows: From 2003 to 2019, technical progress had a significant positive impact on the carbon productivity of China’s service industry. The influence coefficients of technical progress of non-energy factors and technical progress of energy factor are 0.285 and 0.306. In terms of the type of technical progress, the technical progress of energy factor has a greater impact. The technical progress of non-energy factors and energy factor have a significant promoting effect on the improvement of carbon productivity of service industry in all regions of China. In Eastern, central and Western China, the influence coefficients of the former are 0.318, 0.289 and 0.266, and the influence coefficients of the latter are 0.352, 0.296 and 0.273. The mechanism test finds that the technical progress of non-energy factors and energy factor directly affect the carbon productivity of China’s service industry on the one hand, and indirectly affect the carbon productivity of China’s service industry through the production efficiency and energy use efficiency of the service industry on the other hand.

Extrato de alga Ascophyllum nodosum e nitrogênio mineral em mudas de Alibertia edulis

ABSTRACT Physiological and nutritional management is an important practice for obtaining high quality seedlings. The use of seaweed extract has emerged as an alternative to fertilizers and biostimulants, although information on this with respect to Alibertia edulis, a fruit-bearing species native to the Cerrado region, is scarce. The aim of this study was to evaluate the effects of the Ascophyllum nodosum L. seaweed extract (ANE), both with and without the addition of mineral nitrogen, on the growth, nitrogen nutrient efficiency indices, and quality of A. edulis seedlings. The seedlings received five doses of ANE (0, 5, 10, 15, and 20 mL L-1 of water) via foliar application, with and without the addition of mineral N to the soil (50 mg kg-1 of urea). A randomized block design was used with the treatments arranged in a 5 × 2 factorial scheme. The plant height, stem diameter, chlorophyll index, and number of leaves obtained were analyzed in split-plots over time. Foliar application of 15 and 20 mL L-1 of ANE contributed to greater growth and seedling quality, regardless of the addition of mineral nitrogen. Seedlings treated with mineral N alongside 13.98 mL L-1 of ANE showed the greatest leaf area. The highest N use efficiency, N uptake, and nutrient use occurred in seedlings that received A. nodosum extract.

Creation of improved UXK equipment for cleaning cotton from large impurities

This article establishes a number of requirements for cotton fiber processing enterprises to improve production efficiency and rational use of resources and maintain high rates of natural quality of cotton fiber during processing. In addition, as a result of the research, it was found that changing the impact pressure of the scraper brush, creating a new shape of the scraper device, changing the relative position of the grate and the scraper brush, placing an additional scraper device after the scraper brush, so as not to be part of the dirty mixture that separates the piece of cotton, were found some positive results. The proposed design of the cotton cleaning section of the UXK purifier, due to the above features, makes it possible to increase the cleaning effect compared to the existing purifier, since in the proposed version, the process of cleaning cotton from large impurities is carried out twice in each section of the USC, which cleans cotton from large impurities. The proposed technical solution was taken as a basis and a plan was developed for preparing its structural diagrams and working drawings, manufacturing a laboratory stand for the cleaning section, conducting laboratory experiments with it, substantiating the main parameters of the working bodies according to the proposed scheme, and introducing the proposal into production.

Responses to the Impact of Drought on Carbon and Water Use Efficiency in Inner Mongolia

The dynamics of plants’ carbon and water use efficiency and their responses to drought are crucial to the sustainable development of arid and semi-arid environments. This study used trend analysis and partial correlation analysis to examine the carbon use efficiency (CUE) and water use efficiency (WUE) of Inner Mongolia’s vegetation from 2001 to 2020. MODIS data for gross primary productivity (GPP), net primary productivity (NPP), potential evapotranspiration (PET), evapotranspiration (ET), drought severity index (DSI), and plant type were used. Altered trends were observed for drought during 2001–2020 in the study area. The results revealed that 98.17% of the research area’s drought trend was from dry to wet and 1.83% was from wet to dry, and the regions with decreased drought regions were broadly dispersed. In 2001–2020, CUE in Inner Mongolia declined by 0.1%·year−1, whereas WUE reduced by 0.008 g C·mm−1·m−2·year−1, but the total change was not significant. CUE decreased from west to east, whereas WUE increased from southwest to northeast. DSI and CUE had the highest negative connection, accounting for 97.96% of the watershed area, and 71.6% passed the significance test. The correlation coefficients of DSI and WUE were spatially opposite to those of CUE and DSI. In total, 54.21% of the vegetation cover exhibited a negative connection with DSI. The CUE and WUE of different vegetation types in Inner Mongolia were negatively correlated with the DSI index except for grasslands (GRA). Drought in Inner Mongolia mostly influenced the CUE of different plant types, which had a higher negative correlation than WUE. The study’s findings can inform climate change research on Inner Mongolia’s carbon and water cycles.

Spectroscopic, electronic properties analysis for 2, 6-Bis (phenylamino)-4-(iminophenyl) benzoquinone molecule and molecular docking clarification for its anticancer activity detected by strong inhibition of NQO1 enzyme

Quinone compounds have been the subject of extensive research due to their remarkable efficiency and prospective use as drugs and in a variety of fields. In this study, we report the spectroscopic characterization, electronic structure, ADMET evaluation, and molecular docking assessment of 2,6-Bis(phenylamino)-4-(iminophenyl)benzoquinone as an anticancer drug. By using DFT investigations, the vibrational wavenumbers were calculated and utilized to assign vibrational bands, which were found to be in good accordance with the experimentally observed data. The analysis of the UV-Vis spectra revealing an absorption peak from electronic transitions HOMO→LUMO at 547 nm is found to be in good conformity with its experimental value. The HOMO and LUMO frontier molecular orbitals and their associated energies highlighted the mechanism of charge transfer within the molecule and revealed a small energy gap. The chemically reactive sites identified by the MEP surface helped predict the spots of the molecule's biological activity. According to NBO analysis, the π C9-C10 → π* C11-C12 interaction has the maximum energy stability with 23.74 Kcal/mol., due to π electron delocalization within the ring. At the same level of theory, third-order NLO polarizability was found to be 4-fold stronger than the third-order of P-NA (a prototype NLO molecule). The potential for a safe oral bioavailability drug was identified by computing ADMET parameters and evaluating drug-likeness based on Lipinski's rule of five. The molecular docking study found that the molecule binding to NQO1 receptor protein with superior binding energy -8.69 kcal/mol than previously studied Quinone derivatives. Additionally, molecular dynamics simulations were performed to test the dynamic behavior of the ligand-NQO1 complex. The complex was stable in the binding pocket of the receptor proteins, according to the analysis of the simulation outcomes such as RMSD and RMSF. These results suggests using this molecule as a potential anticancer drug due to its high capability to inhibit the NQO1 enzyme.

Photosynthesis rate, radiation and water use efficiencies of irrigated potato in a semi-arid climate using Eddy covariance techniques

AbstractUnderstanding the photosynthetic behaviour, radiation use efficiency (RUE) and water use efficiency (WUE) of potatoes in response to diurnal and seasonal fluctuations in weather, is important for optimizing growth and production. The net ecosystem exchange (NEE) of carbon dioxide (CO2), is a parameter used to measure the balance between gross CO2 assimilation (also referred to as gross primary production (GPP)) and ecosystem respiration (Reco). The objectives of this study were (i) to quantify the NEE of potato grown in two contrasting agro-ecologies and partition NEE into Reco and GPP; (ii) to describe seasonal patterns in daily photosynthesis, RUE and WUE in potato; and (iii) to analyse the variability in photosynthesis rate, RUE and WUE as affected by weather and crop growth stage. We measured CO2 and water vapour fluxes using eddy covariance techniques in potato fields in two production regions of South Africa. The winter crop had higher mean RUE and WUE values, whereas the summer crop absorbed more CO2. RUE had a negative relationship with incident radiation. To optimize dry matter production, WUE and RUE, potato crops must be well established and develop a full canopy early during the season. Maintaining the crop for a longer period in the field has yield benefits, although they appear to decline over time due to reduced efficiencies as the crop matures. The RUE observed over the growing period in the present study was high, relative to findings by other field studies, despite relatively warm growing conditions that were likely sub-optimal for potato.

Effect of Nitrogen and Phosphate Fertilizer on Phosphorus Uptake and Phosphorus Use Efficiency in Some of Wheat Varieties (T. aestivum and T. durum)

A field experiment was carried out in a subtropical region of India. The main purpose of this experiment was to grow different wheat genotypes under different nutrient doses and find out which genotype performed better in terms of yields and other attributes under nutrient constraints. Nine varieties of wheat (T. aestivum and T. durum L.) were selected and grown as test crops in the current investigation, adopting a split plot design that was replicated three times, with nutrient dose as the main plot and varieties as sub treatments. In the treatmentT1 = control, T2 = 100% (N+P+K), T3 = 50% N+100% (P+K), and T4 = 50% P+100% N+K, there are 36 plots in a block (9 varieties x 4 fertilizer N and P treatments). Of the nine varieties grown under normal N and P conditions, varieties NARMADA 14 and GW 366 had the highest P content in grain and straw. GW366 (10.93 kg/ha) had the highest average total P uptake, followed by NARMADA14 (10.90 kg/ha). Under normal doses of N and P, the variety HI 1531 (15.25%) had the highest apparent recovery of P, followed by NARMADA14 (15.15percent).Across all fertilizer N and P dosages, the highest average agronomic efficiency for P was found in GW366 (40.09%), followed by LOK1 (37.93%). NARMADA 14 and GW366 have the highest P content in grain and straw of the nine varieties grown under normal nitrogen conditions. Agronomic use efficiency and physiological use efficiency were generally substantially higher when computed on a P basis than they were when calculated on an N basis. P fraction concentrations in black soil varied, but they responded similarly to crop species and N sources. The N supply had an impact on the amounts of P taken from the soil. In P-deficient soils, the use of an appropriate N source and the selection of the right crop species may boost crop yield and plant P uptake.

Comparing water related indicators and comprehensively evaluating cropping systems and irrigation strategies in the North China Plain for sustainable production

The fully irrigated winter wheat–summer maize double cropping system (DWM) has caused groundwater overexploitation and aggravated water scarcity in the North China Plain (NCP). Therefore, it is necessary to select alternative cropping systems with effective irrigation strategies to maintain the sustainable use of groundwater and maintain crop productivity. However, the evaluation indicators, especially the water-related indicators of cropping systems and irrigation strategies in current studies are not consistent and it is difficult to obtain a comprehensive evaluation result. Hence, to overcome these challenges, this study reviewed and compared groundwater indicators, water use indicators, water production performance indicators and output indicators, and summarized twelve evaluation combinations. Four evaluation combinations with grain yield as output indicator were selected to comprehensively evaluate the cropping systems and irrigation strategies developed by Agricultural Production Systems sIMulator (APSIM) at a typical site in the NCP in the past 52 years. The indicator weights were determined by analytic hierarchy process, entropy weight method, random forest algorithm and principal component analysis. Evaluation results showed that when the main goal was to guarantee food safety or improve the beneficial water use, the DWM was selected as the best choice and the WMM (winter wheat–summer maize → spring maize system, three crops in two years) was the alternative cropping system. Under this condition, water saving irrigation should be vigorously developed to reduce groundwater exploitation. When the four indicator types had the same weight, the DWM under rainfed was the best choice to improve evapotranspiration use efficiency and precipitation use efficiency; the monocropping spring maize system under normal irrigation strategy was the best choice to reduce water footprint. The WMM under rainfed was the alternative choice to improve evapotranspiration use efficiency, improve precipitation use efficiency and reduce water footprint. The evaluation methods proposed in this study could be used as reference in the comparison of cropping systems and irrigation strategies in other water-related situations.

Quantitative Description and Classification of Growing Media Particle Morphology through Dynamic Image Analysis

The physical properties of growing media are dependent on the morphological characteristics of the particles composing them. Thus, their characteristics can be more precisely altered for specific purposes by a better morphological design of materials to optimize the use of raw materials and increase water efficiency. There are many references on the relationship between basic particle size and physical properties, but the arrangement of the particles and the resulting physical properties are also affected by the shape of the particles. Growing media have seldom been characterized by shape criteria and, therefore, their influence remains unknown. A dynamic image analyzer, the QicPic device, was used to assess particle shape and size for a wide diversity of growing media constituents. As well as FeretMAX and ChordMIN diameters describing individual particle length and width, respectively, individual particle shape was analyzed in terms of several descriptors (aspect ratio, circularity, roundness, and convexity). A classification was established to discern different particle shapes and all materials were described accordingly. Correlations between particle morphology descriptors were reported, showing that the greater the particle length, the smaller the width/length ratio, circularity, roundness, and convexity. Circularity, roundness, particle length, and its associated relative span were identified as the most relevant parameters describing materials’ morphology. This work shows a large diversity in particle morphology of growing media constituents, which were categorized into four classes of materials. Three classes were mainly described according to their particle shapes, with a decreasing elongation and an increasing circularity, roundness, and convexity: (1) fine and coarse wood and coir fibers; (2) all Sphagnum white peats, milled or sod; and (3) black peats, sedge peat, coir pith, fresh and composted pine bark, green waste compost, and perlite. A fourth class was represented by coir medium (mixing pith and fibers) and was above all characterized by high diversity in particle length. These findings extend the characterization of the materials for a more thorough evaluation of the links between particle morphology and physical properties.

Interaction Effects of Sowing Date, Irrigation Levels, Chitosan, and Potassium Silicate On Yield and Water Use Efficiency for Maize Grown Under Arid Climate

Adopting foliar antiperspirants reduces the negative effects of water stress on crop production. In this study effects of chitosan (Ch) and potassium silicate (PS) on maize sowing at two sowing dates under irrigation water levels (100% of irrigation water applied −Ir00 and 70% of irrigation water applied −Ir70) were investigated. Thus, during the spring and fall seasons of 2020–2021, a field experiment of two similar experiments was conducted at the experimental farm of Water Studies and Research Complex (WSRC) station, National Water Research Center, Toshka—Abu Simbel City, Egypt, which the sowing dates were allocated in the main plot, then a strip-plot design with five replicates was used. It was found that sowing maize seeds in the fall season led to attaining a higher maize yield than in the spring. Moreover, the adoption of Ir70 provides better maize yield and water use efficiency than Ir100, particularly at the fall season sowing date. In addition, the adoption of the higher Ch concentrations in the spring, led to better improvements in maize yield particularly under Ir70, while the adoption of the higher concentrations of PS in the fall seasons, led to better maize yield. It was concluded based on present findings that applying chitosan as foliar applications with concentrations at 500 (mg l−1) under Ir70 in the fall had significant effects to maintain the higher maize yield, water use efficiency and irrigation water use efficiency in the arid regions as Toshka district and other similar areas.

DAA - directly acting antivirals - as a new, more efficient solution of the chronic hepatitis C treatment and theirs various application.

Introduction Cirrhosis is a condition in which the liver becomes fibrotic following damage to the liver and transforms the architecture of the organ into regenerative nodules. The disease is caused 30% by HCV infection, resulting in a risk of severe complications and death. Since the use of direct-acting antivirals ( DAAs) for the treatment of chronic HCV, sustained virological response (SVR) rates have begun to increase, even in treatment-resistant cases. Studies have also shown that DAAs may have applications in other viral diseases and even In the treatment of breast cancer. Aim of the study The purpouse of our study was to review scientific articles to show the efficiency and potential use of DAAs in the treatment of chronic HCV, and to identify possible directions for further research. Methods and materials We reviewed the English literature in the PubMed, using the key words: "simeprevir" ; "sofosbuvir" ; "velpatasvir" ; "telaprevir" ; "chronic hepatitis C". Results Studies have shown that the therapeutic regimens currently being designed with (DAAs) offer the possibility of treating almost the entire population with hepatitis C, while reducing side effects of interferon therapy such as increased AST, ALT activities, diarrhoea, vomiting, nausea and depression. They remain effective and tolerable, regardless of the stage of cirrhosis and associated serious co-morbidities. Analysis of studiem shows, that DAAs also show efficacy against other disease such as breast cancer, MRSA infections, SARS-CoV-2 or flavivirus infection. Conclusion All (DAAs) are effective in the treatment of patients with HCV, including cirrhosis. They result in significant improvements in prognosis and clinical outcomes. Promising results have been obtained in published data on the effect of DAAs against disease entities other than HCV, suggesting the rationale for future clinical trials to further the hypothesis of the increased potential of these drugs.

Energy efficiency and water use indices for sweet potato (Ipomoea batatas L.) production under subtropical climatic conditions of Bangladesh

Abstract To estimate energy use efficiency for sweet potato production in Bangladesh under subtropical climatic conditions, a study was conducted with 60 individuals (12 producers for each sweet potato variety) by using a structural questionnaire. The results revealed that the majority of the energy input was consumed by the pre-harvest activities (22,313.55 MJ ha−1 or 90.85%), of which fertilizer application (36.84%) and irrigation (35.24%) consumed the most energy input, with only 9.15% (2,248.42 MJ ha−1) consumed by the post-harvest activity for sweet potato production. The energy input involved in the production system was similar to the direct (12,149.76 MJ ha−1 or 49.47%) and indirect (12,412.21 MJ ha−1 or 50.53%) sources, while it was much higher in non-renewable sources (22,884.21 MJ ha−1 or 93.17%) with a minimum (1,677.76 MJ ha−1 or 6.83%) from renewable sources. The average energy use efficiency, energy productivity, specific energy, net energy, energy profitability and water-energy productivity of orange-fleshed sweet potato (OFSP) varieties 4.36, 1.22 kg MJ−1, 0.83 MJ kg−1, 82,511.73 MJ ha−1, 3.36 and 1.32 g m−3 MJ−1, respectively. The OFSP varieties showed better performance in respect of all the energy and water use indicators.

THE PURPOSES AND METHODS OF ENERGY SYSTEM MODELING

This article describes the purpose of energy system modeling and the classification of planning models according to approaches and methodologies. The advent of modern computers and computer programs has simplified the use of planning models. Such models employ powerful mathematical algorithms and databases which can solve highly complex problems in a relatively short time. This has led to energy-ecology-economy (E3) models, which are simultaneously able to consider questions in connection with energy supply, ecology and economics. The characteristics of a MARKAL model are presented separately through an example of integration with other planning models. It is demonstrated that the application of an optimizing MARKAL model for the planning of the energy supply system of the Republic of Croatia is of great significance for the analysis of the energy market of South Eastern Europe, the use of renewable energy sources, energy efficiency and emission trading.