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In agriculture, the transformation and drying industries have the most share of energy consumption. The present study aims to optimize the drying process of apple pulp sheets. This process includes checking the energy consumption values and emission of greenhouse gases by the vacuum system in the normal atmosphere (Natm) and controlled atmosphere (Catm) methods. Experiments were conducted at five drying chamber temperatures (i.e., 45, 55, 65, 75, and 85 ℃) and five vacuum pressures (i.e., 40, 50, 60, 70 and 80 kPa). Optimizations were performed using the response surface methodology and the central composite design. The optimum point of apple pulp sheets drying for a gas turbine-oil gas power plant was obtained at a drying temperature of 84.9 ℃ and vacuum pressure of 60.6 kPa. The desirability index was 0.9936 under these conditions. Besides, the optimal value of the response variables, including drying time, total energy consumption (EC), specific energy consumption (SEC), NOX emission, and CO2 emission, were 205 min, 7.65 kWh, 339.02 kWh/kgwater, 1962.94 g/kgwater, and 210,872.40 g/kgwater, respectively. The results showed that in the Catm method, the EC, SEC, NOX, and CO2 from the oil gas turbine power plant were about 19.22%, 37.19%, 37.19%, and 62.72% less than the Natm method, respectively. Therefore, using a vacuum dryer and applying the Catm method in the gas turbine oil of a gas power plant is more economical regarding environmental pollution than the vacuum dryer using the Natm method. [ABSTRACT FROM AUTHOR]

Walnut green husk (WGH) is a common agricultural by-product with high yield and serious pollution problem. The present study aimed to evaluate the impacts of sun drying (SD), pulsed vacuum drying (PVD), short and medium infrared radiation drying (SMIR), hot air drying based on temperature and humidity control (TH-HAD), and heat pump drying (HPD) on the drying characteristics, energy consumption, physico-chemical properties, bioactive compounds content and antioxidant capacity of WGH. Drying characteristics and drying kinetics showed that artificial drying could significantly improve drying efficiency. Compared with SD, the drying time of PVD, SMIR, TH-HAD, and HPD reduced by 63.6, 78.7, 66.3, and 54.0%, respectively. Specific energy consumption analysis demonstrated that HPD showed the lowest specific energy consumption of 2.2 kW·h/kg. Hydration properties analysis revealed that PVD resulted in sample of best water-holding capacity and the HPD sample had the highest water solubility index (43.44%). Structural analysis showed that the cell wall structure of WGH was damaged by different drying methods. Generally, among the five drying methods, HPD was found to be in the middle range in terms of active substance content and antioxidant capacity of dried samples, but it had the least energy consumption. Therefore, HPD has great potential for commercial-scale drying of WGH, offering a new approach for low-energy food processing. [ABSTRACT FROM AUTHOR]

Background: Reducing energy consumption and greenhouse gas emissions is a crucial issue in the cassava starch processing industry. In this study, the integrated system combining livestock, cassava cultivation and cassava production in the same area leads to both a zero emission goal and economic efficiency, a typical example of an effective agro-industrial symbiosis. A heat exchange/recovery system was applied including the economizer, heat exchanger tank, biogas tank, and boiler. The economizer attached to the boiler's chimney transfers heat from exhaust gases for pre-heating feed water entering the boiler. The biogas tank recovers energy from the wastewater of starch production and livestock, and the generated biogas was used as fuel for the boiler. Results: The energy and exergy efficiency, energy losses, and exergy destruction for the heat recovery system were analyzed. The specific energy consumption was used to evaluate the overall energy efficiency for a cassava starch factory with a capacity of 20 tons/day. The results show that there is a high potential to recycle waste into energy in the cassava starch industry. The total energy saving and reduced greenhouse gas emissions per year of the cassava starch factory were 0.054%/year and 123,564 kgCO2/per year, respectively. Conclusions: Cassava starch factories can save energy and reduce emissions when applying a heat recovery system in the integrated agro-industrial system. Excess heat from the production was used for evaporating (removal of) NH3 in wastewater flow from the biogas tank, and for heating the biogas system to enhance the efficiency of methane production. A biochar filter was attached to the economizer for adsorption of released ammonium, and the biochar after adsorption was combined with sludge from the biogas tank to produce a solid biofertilizer. [ABSTRACT FROM AUTHOR]

Energy saving and consumption reduction is one of the current important research in the field of green and sustainable manufacturing. Products or components containing variable curvature contouring are widely used in the automotive, medical, aerospace, and mold industries, while there is a lack of methods to model the energy consumption ratio for variable curvature contouring and improve its energy efficiency. A method for modeling the specific energy consumption of variable curvature contouring and energy consumption optimization is proposed for this problem. Firstly, the components of energy consumption in processing of the CNC machine tool machining are analyzed, and the relationship between curvature characteristics and material removal rate is investigated from the geometric perspective. Secondly, orthogonal experiments with different curvatures of straight lines, convex arcs, and concave arcs are designed to collect energy consumption data. Based on the experimental data, the Dueling Deep Q-Network optimization support vector regression (Dueling DQN-SVR) was used to establish the specific energy consumption model considering the curvature. Finally, a multi-objective optimization model is constructed when considering specific energy consumption, efficiency, and quality, and the Pareto solution set is solved using a multi-objective Gray Wolf optimization algorithm (MOGWO). The Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) method was used to select the optimal combination of machining parameters. The experimental results show that the accuracy of the established model is more than 95%. The method improved energy efficiency by more than 7.82% and efficiency by more than 1.128%. These research results are of great theoretical and practical significance for achieving energy-efficient variable curvature contour machining. [ABSTRACT FROM AUTHOR]

This study investigates how temperature and forward osmosis (FO) membrane properties, such as water permeability (A), solute permeability (B), and structural parameter (S), affect the specific energy consumption (SEC) of forward osmosis-reverse osmosis system. The results show that further SEC reduction beyond the water permeability of 3 LMH bar-1 is limited owing to high concentration polarization (CP). Increasing S by 10-fold increases FO recovery by 177.6%, causing SEC decreases by 33.6%. However, membrane with smaller S also increases external CP. To reduce SEC, future work should emphasize mixing strategies to reduce external CP. Furthermore, increasing the temperature from 10 to 40 °C can reduce SEC by 14.3%, highlighting the energy-saving potential of temperature-elevated systems. The factorial design indicates that at a lower temperature, increasing A and decreasing S have a more significant impact on reducing SEC. This underlines the importance of developing advanced FO membranes, particularly for lower-temperature processes. [ABSTRACT FROM AUTHOR]

A global manufacturing community is dedicatedly striving to implement the concept of NetZero in precision cutting of difficult-to-machine materials, specifically, Inconel 617 (IN617) with due consideration to environmental protocols. The fast strain hardening issue of the said alloy during conventional processing rationalizes the application of electric discharge machining (EDM). However, EDM has been criticized for its high energy consumption and limited cutting efficiency. Moreover, conventional dielectric (kerosene) employed in EDM has drastic environmental and operator health concerns. To address the abovementioned issues, waste cooking oil (WCO) has been employed in this study which enhances the reusability of resources and minimizes the cost of the dielectric. Making the process sustainable is imperative along with continuously escalating scarcity of engineering resources. Therefore, the potential of shallow and deep cryogenically treated electrodes (SCT and DCT) has been comprehensively examined against nanofilled WCO to achieve the aforementioned objective. Three different concentrations of powder (Cp) and surfactant (Cs) to uplift the machining responses are investigated through a detailed parametric experimental design. Core machining factors such as material removal rate (MRR), surface roughness (SR), and specific energy consumption (SEC) are examined through optical and electron microscopy studies and 3D surface profilometry. Hereafter, machining factors are modelled using the artificial neural network (ANN) technique. An exceptional improvement of 80%, 25.3%, and 75.16% has been achieved in MRR, SR, and SEC respectively using nanopowder-mixed WCO against SCT brass compared to the responses' values obtained against conventionally used kerosene. Furthermore, compared to kerosene, the maximum CO2 reduction of 79.97 ± 11.2% is achieved with WCO. [ABSTRACT FROM AUTHOR]

The awareness of energy consumption is gaining much more attention in manufacturing due to its economic and sustainability benefits. Reducing energy consumption in advanced manufacturing processes, like directed energy deposition (DED) manufacturing, is critical for Industry 4.0 and the forthcoming Industry 5.0 since it allows for more economical, sustainable, and environmentally friendly manufacturing approaches. An energy consumption model is needed for quantifying the consumption and predicting the impact of various process parameters in manufacturing. This paper aims to develop an energy consumption model for DED-based hybrid additive manufacturing (HAM) for an Inconel 718 part. The specific energy consumption (SEC) is used while developing the energy consumption of the product manufacturing lifecycle. This study focuses on the analysis to investigate three significant factors (scanning speed, laser power, and feed rate), their interactions' effects, and whether they have a significant effect on energy consumption. The results suggest that all the factors have a strong influence, but their interaction effects have a weak influence on the energy consumption for HAM. Among the three process parameters, it is found that laser power has the most significant effect on energy consumption. Again, based on the regression analysis, this study also recommends high scanning speed while the laser power and feed rate should be low. Also, idle time has significant energy consumption during the whole HAM process. [ABSTRACT FROM AUTHOR]

The present study demonstrates a comprehensive characterisation of an Indian iron ore sample to investigate the effect of blending coarse particles with fine particulate slurry on the rheology, slurryability, and stability of iron ore suspension. Various bench-scale tests are carried out to determine iron ore samples' physico-chemical, morphological, and flow characteristics. The iron ore samples with three distinct particle size ranges (< 38, 38–75, 75–106 µm) are used to prepare eight different bi-modal slurry samples. The rheological characteristics of the slurry are investigated at a shear rate range between 50 and 600 1/s, and regression analysis is performed to evaluate the nature of the slurry. Finally, the best particle size distribution is evaluated based on critical parameters such as apparent viscosity, settling characteristics, pressure drop, and specific energy consumption. The optimal proportion of coarse particles (38–75 µm) blending in the slurry suspension of fine particulate is observed at 40% (by weight), while in the case of the coarse particle (75–106 µm), it is 30% (by weight). Maximum pressure drop reduction recorded for the optimal proportion bi-modal samples I7 and I10 at 40, 50, 60, 70, 75, and 80% concentrations is 57.6, 56.81, 55.2, 52.45, 49.31, 46.3%, and 57.98, 59.18, 56.2, 54.74, 50.86, 48.15%, respectively. In contrast to uni-modal samples, the specified bi-modal samples with an optimal particle size distribution showed significantly lower yield stress, viscosity and enhanced solids loading in the slurry. [ABSTRACT FROM AUTHOR]

In this study, a new method for the LNG has been proposed based on the SMR process. In the proposed process, an ORC is added to the conventional SMR process and the BOG is used as a coolant in the main heat exchanger. ASPEN HYSYS software utilizing the Peng–Robinson equation of state is used to simulate the SMR and SMR-ORC. The specific energy consumption, total exergy efficiency, and carbon dioxide emissions of the proposed method are compared with the conventional SMR process. Finally, an economic evaluation was performed on both processes. The simulation results showed that in the conventional process the total exergy efficiency and specific energy consumption are 34% and 647 kWh ton , respectively, while in the proposed process the total exergy efficiency has reached 39% and the energy consumption is reduced to 472 kWh ton . Also, the environmental assessment of carbon dioxide emissions from the production of electrical energy required by pumps and compressors showed that the proposed process has 28.51% less carbon dioxide emissions than the conventional SMR method. [ABSTRACT FROM AUTHOR]

The current study evaluated the performance parameters and drying characteristics of muskmelon slices in the indirect forced convection solar dryer (IFCSD) without thermal energy storage (TES) device (case-A) and with a TES device (case-B). The average collector and drying efficiencies (ηSAC and ηdr) were 66.37 and 11.37% in case-A and 67.82 and 16.93% in case-B, respectively. The ηSAC of both setups was not affected by the TES as it was installed in the drying cabinet, whereas ηdr of case-B setup was improved because the stored and released heat was more, also, the drying completed within a day compared to case-A. The six sunshine hours were saved, and a 53.98% average drying rate was improved by case-B. The specific moisture extraction rate was improved by 74.19%, and the specific energy consumption was decreased by 42.56% compared to case-A due to the higher quantity of moisture removal per input solar radiation in case-B. Two-term exponential and Page models were appropriately suited for drying muskmelon slabs in case-A and case-B, respectively. The values of effective moisture diffusivity, heat and mass transfer coefficients (averages) were improved slightly by TES device in case-B. The temperature of the drying cabinet could be continued 4.5 to 8.9 °C greater than the atmospheric temperature in case-B after the sunset. The performance of IFCSD was better in case-B compared to case-A, and the final moisture content was achieved within a day in case-B. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of different electrode pairs in the treatment of strained yoghurt wastewater with electrochemical oxidation method and the operating conditions in the reactor (distance between electrodes and applied potential) in specific energy consumption (SEC) for COD removal were investigated by applying the Taguchi experimental design and ANOVA analysis. For different electrode pairs, the highest COD removal was obtained as 24.79–28.9%, and it was observed that the electrode type did not have a significant effect on organic matter removal. It has been found that the operating conditions for different electrodes show similar trends for SEC in COD removal. The applied potential for all electrodes was determined as the most effective operating condition, followed by the reaction time and the distance between the electrodes. According to the results of ANOVA, the correlation coefficients of different electrode pairs were determined in the range of 82.33–91.21% for the SEC in COD removal. SEC under the studied experimental conditions is between the following values: 0.0019–2.5695, 0.0011–0.5702, 0.0007–0.5721, and 0.012–0.3641 kW h kg COD−1 for steel (anode)–steel (cathode), graphite (anode)–graphite (cathode), graphite (anode)–steel (cathode), and BDD (anode)–graphite (cathode) electrode pairs, respectively. It is thought that the electrochemical oxidation process will be a good alternative treatment method for strained yoghurt wastewater, which has a very high COD content and low pH value, as a post-treatment unit or in combination with other methods, due to an effective COD removal at low reaction times and low SEC. [ABSTRACT FROM AUTHOR]

As the movement for carbon neutrality spreads around the world, research on hydrogen energy is also being actively conducted. In the hydrogen value chain, liquefaction is a particularly energy-intensive process. Although the operating energy of the hydrogen liquefaction process can vary greatly depending on the season or regional cooling water temperature, previous studies have not taken this into account. In this study, we quantitatively identify the effect of the change in cooling water temperature on exergy destruction, specific energy consumption (SEC), and coefficient of performance (COP) of the liquefaction process. In addition, we propose a design improvement to reduce exergy destruction with the exergy analysis of multi-stream heat exchangers. A new design (auxiliary process) that reduces exergy destruction is proposed by analyzing the device where energy destruction occurs the most. When the cooling water temperature increases from 20 °C to 35 °C, there is a tendency for SEC and exergy destruction to increase and the COP to decrease. The new design with an auxiliary process shows a decrease in SEC and a reduced rate of increase in SEC in response to the increase in cooling water temperature. The base case without the auxiliary cycle shows that the SEC with cooling water of 35 °C is 14.66% greater than that with cooling water of 20 °C, while the proposed process shows the rate of increase of 9.70%. This means that adding the auxiliary cycle can improve the energy efficiency and increase robustness to variations in ambient conditions. [ABSTRACT FROM AUTHOR]

This study focuses on green coffee beans (Coffea arabica) drying kinetics in a tray dryer within the range of 50–60 °C. The kinetic parameters were estimated using several theoretical, semi-empirical models in which the semi-empirical model was well fitted with the experimental data and the two-parameter model and least error in Logarithmic model with the observation of kinetic parameter (k) increases with temperature. Arrhenius equation was used to find the activation energy (Ea) as 40.413 kJ/mol and the effective diffusivity coefficient also varied from 1.0833 × 10–9 to 6.1862 × 10–9 m2/s. The surface heat and mass transfer coefficients (h and hm (average)) were found to be 14.14 W/m2 K and 0.0344 m/s. Thermodynamic properties such as enthalpy (ΔH), entropy (ΔS) and Gibbs free energy (ΔG) were 37.5293 kJ/mol, − 0.211 kJ/mol K and 106.931 kJ/mol. The parameters such as specific moisture extraction rate (SMER), moisture extraction rate (MER) and specific energy consumption (SEC) were estimated as 0.001659 kg/kWh, 0.0033195 kg/h and 602.5 kWh/kg and the observed results are higher as compared to other literature. [ABSTRACT FROM AUTHOR]

In this work, the impact of good manufacturing practices (GMP) on the specific energy consumption (SEC) of plastic injection molding process, in 9 representative companies in Colombia, was studied. The GMP applied to the injection molding process and the degree to which they are adopted by the companies were defined. Afterwards, the SEC of 17 representative injection molding processes in those companies were evaluated. Finally, the impact of applying the GMP and their effect on SEC were studied. The degree of application of GMP on the analyzed companies ranges from 35 to 72%. A single SEC value could not be established for all the injection systems, because it depends on the injected weight and the productivity of each mold-machine-material combination. Nevertheless, a characteristic curve was defined for different systems. A relationship between the application of GMP and SEC was found. It was observed that all GMP contributed to improve the SEC, with different significance, ranging the relevance from 6 to 14%. Finally, it was concluded, taking in consideration a representative company, that “Plasticizing” and “Drive Units” were the most relevant categories to impact the SEC. [ABSTRACT FROM AUTHOR]

Türkiye is one of the biggest developing countries and the second biggest cement exporter in the world. In 2021, the country exported around $1billion of cement, which is responsible for over 8% of emissions globally. In order to fulfill the EU norms, energy, emissions, and cost reduction investments continue in the country. The aim of this paper is to perform a detailed exergoeconomic assessment of a rotary burner to increase the energy and exergy performance and decrease energy consumption, exergy costs and environmental impacts of a real scale cement factory in Türkiye. During the 2-year period, detailed data has been obtained from the factory by real time detection of clinker manufacturing process. By applying the specific exergy costing (SPECO) method, energy and exergy destructions, and exergetic cost distributions for the rotary burner are calculated in detail. The 1st and 2nd law efficiencies of the overall factory, specific energy (SEC) and exergy (SExC) consumption, and SPECO for clinker production are calculated to be 59.84%, 39.04%, 4786.75 MJ/ton, 5230.38 MJ/ton, and 10.11 $/MJ, respectively. The use of magnesia-spinel composite refractory bricks and the anzast layer formation decreased the SPECO by 2.71% corresponding to a saving of $2,280,000 preventing 13.74 MtCO2 emissions yearly. [ABSTRACT FROM AUTHOR]

Industrial process heat decarbonization through electrification could contribute significantly to climate change mitigation efforts. In the US industry, thermal processes accounted for more than two-thirds of the total final energy demand in 2021. Cross-cutting electrification technologies like industrial heat pumps are suitable for the process heat supply to several industrial unit operations in a sustainable way while also improving overall energy efficiency. This study employs a bottom-up approach to investigate the techno-enviro-economic potentials of deploying high-temperature and steam-generating heat pumps in US textile, pulp and paper, and automotive sectors in different timeframes. The results show that the annual technical potential energy and CO2 savings by electrifying heat supply are 310 PJ (or 36% of the projected energy demand) and 28 MtCO2 (or 71% of the projected CO2 emissions) in 2050 respectively, however, these incur additional costs in each sector (ranging between 5 and 18 $/GJ). The required heating capacity of industrial heat pumps is estimated at 15 GW, which translates roughly into a market of over 6000 heat pump units and an investment volume of $7 billion in the studied processes. Although there may be individual cost-effective opportunities for electrifying heat supply in specific industrial sites, the overall costs are estimated to be high in the three industrial sectors due to the large disparity between electricity and natural gas prices and low heat source temperatures. To overcome the identified techno-economic barriers, comprehensive action plans for different stakeholders are also given. This study provides novel insights that should inform policymakers’ and executives’ decisions about the electrification of the current and future US industrial heat supply in relevant industrial sectors. [ABSTRACT FROM AUTHOR]

The thermal energy content of sewage sludge (SS) is close to that of low-grade fuels. Drying is the most energy-consuming process in the conversion of sludge to biofuel. However, the energy efficiency of the drying system is not sufficiently emphasized. In this study, the energy efficiency of the sludge drying process is investigated using an experimental contact-type dryer. The effects of wall temperature, rotation speed, and waste heat usage alternatives are investigated. Waste heat usage has the highest impact on energy efficiency. Flue gas feeding increases the drying rate and reduces the total drying duration. Energy efficiency is increased with increasing temperatures. The rotation speed does not considerably affect energy efficiency. Sludge passes through 3 distinct phases regarding the specific energy consumption (SEC). In the first phase, the sludge temperature increases to the saturation temperature. A rather long period of constant energy consumption follows this phase. Most of the water evaporation and drying period occurs in this phase. SEC values begin to increase in the last phase when humidity is in the range of 0.5–1 (30–50% wb). Considering the first drying stage, a 32–20% higher evaporation rate is obtained with waste heat recovery application depending on the temperature. [ABSTRACT FROM AUTHOR]

Slurry flow (water–glass beads) through a horizontal pipe of diameter, 0.0549 m and length, 3.8 m with two particle sizes, i.e., 125- and 440-micron, has been numerically modeled and investigated based on the kinetic theory of slurry transportation. The effect of particles interaction on the pipe flow characteristics such as velocity profile, wall shear stress, vector regime, granular pressure and temperature has been evaluated at different solid concentration and flow velocity range. It is well established that the pressure drop is the key parameter for the design of efficient slurry pipeline system, which is influenced by factors such as flow velocity, slurry viscosity, solid concentration, pipe material and pipe geometry. However, to best of our knowledge, the estimation of pressure drop at different pipe roughness height and a concentration range of 40–60% is not yet established. Therefore, in the present work, the numerical simulation is carried out for slurry flow through a horizontal pipeline at different roughness heights (Rh = 10–50 micron) and Prandtl numbers, i.e., 1.34, 2.14, 3.42 and 5.83. The kinetic parameters are calculated at a flow velocity (Vm) of 1–5 ms−1 and solid concentration (Cw) range of 40–60%. The results and procedure of the current simulation are validated against the available experimental results in the literature. The outcomes of the present work reveals that pressure drop increases with increase in pipe roughness height for the chosen velocity and solid concentration range. In addition, the larger particle is found to have more influence on the pressure, velocity, temperature distribution for the entire range of flow velocity and solid concentration. Furthermore, settling velocity and specific energy consumption are also predicted and discussed through the slurry pipeline. The findings show that the settling velocity of particle increases with increase in particle size at different Prandtl number. The energy efficiency for solid transportation through pipeline at different Prandtl numbers and particle size are also evaluated. Based on the results, it is concluded that specific energy efficiency varies with solid concentration and particle size, i.e., higher concentration and larger particle size demonstrates higher energy consumption. Furthermore, fluid at low Prandtl number exhibits higher energy consumptions. In order to design the efficient slurry pipeline system, it is recommended that the slurry must be transported at low velocity and high Prandtl number. [ABSTRACT FROM AUTHOR]

The possibility of building liquefied natural gas (LNG) plants of 5-20 tons/h capacity with an external nitrogen refrigeration cycle as an alternative to mixed cycles is investigated. A computational analysis is made and various schemes of natural gas liquefaction with external expansion cycle are compared. Scheme with two expanders is preferable for plants with capacities up to 20 tons/h. The main technical solutions ensuring versatility of the plant with sufficiently high efficiency are worked out. A design of a 5 tons/h LNG plant based on external nitrogen expansion cycle with two expanders is developed for a specific customer. [ABSTRACT FROM AUTHOR]

In this work, the influence of the location of the electrodes on the productivity of electrochemical process and specific energy consumption during direct current electrosynthesis of finely dispersed graphite powder is considered. The authors consider the possibility of using finely dispersed graphite powder obtained by electrolysis as the main component of a multifunctional aerospace coating. For this purpose, two types of devices were constructed: with a coaxial and parallel arrangement of the electrodes. The main elements of the device are a stainless steel cathode and a graphite anode immersed in electrolyte (an aqueous solution of salts). The authors consider the influence of the arrangement of the electrodes in the installation for direct current electrosynthesis from the point of view of the energy efficiency and productivity of electrochemical process. As a result of anodic oxidation, a fine powder from graphite of the MPG-6 brand was obtained. The size of the resulting graphite particles is 1–50 µm. This finely dispersed graphite powder can be used as the main component of a multifunctional coating in aircraft, since it has an even homogeneous structure, as well as higher values of the main mechanical properties of a multifunctional coating, which will lead to a decrease in the number of layers and the thickness of the coating applied. The resulting graphite powder can also be used in the production of fire-retardant and heat-insulating materials for the chemical, nuclear industry, instrumentation, and heat power engineering. [ABSTRACT FROM AUTHOR]

In recent years, the environment has become a very vital issue concerning global trade. In the field of world trade, the main reason for paying attention to the subject of energy is the world government is inventing innovations to reduce climate change, growing costs, and to use natural resources optimally. In Iran, general consumption pattern reforms policies announced in 2010, and energy saving by applying a balanced set of price and non-price measures to continuously reduce the country's "energy intensity index" to at least one-half of the same year by the end of 2026 with Emphasis placed on the policy of reviewing and approving laws related to energy supply and consumption, formulating and enforcing mandatory national standards for the production and import of all energy-intensive equipment and devices, and strengthening the system for monitoring their proper implementation and requiring manufacturers to reform energy-efficient production processes. The energy footprint in the energy industry, which represents the trajectory of energy consumption and its measurement in the production process from the stage of energy provide to the step of use by the final consumer, was identified. Oil refining industries in the form of legal requirements and related standards were required to implement green productivity techniques based on the installation of appropriate technologies and proper management techniques for oil refining that is environmentally friendly and increasing productivity and profitability. In 2015–2018, 378,000,000 Gj of energy is saved in Iran's oil refineries by carrying out these measures. [ABSTRACT FROM AUTHOR]

Energy relationships in electric arc furnaces (EAFs) and the influence of the technological processes in furnace baths on them are considered. The main parameter that determines the efficiency of using electric energy is shown to be the ratio PA.i/Giηel.i. The problems of optimization of the electrical regimes of the furnaces in various heat periods are considered. The concept of an energy coefficient is used to justify the increase in the heat efficiency during the melting period due to an increase in the arc voltage and the furnace current during the period of liquid metal heating. The influence of the relations between the powers of oxyfuel burners (OFBs) and a transformer on the performance of the furnace is analyzed. The influence of various methods of heating a charge on the heat indicators is estimated quantitatively. [ABSTRACT FROM AUTHOR]

Stainless steel is a kind of difficult-to-machine material, and the work hardening in milling easily leads to high energy consumption and poor surface quality. Thus, the influence of machined surface hardness on energy consumption and surface quality cannot be ignored. To solve this problem, the prediction models for machine tool specific energy consumption and surface roughness are developed with tool wear and machined surface hardness considered firstly. Then, the validity of the models is verified through AISI 304 stainless steel milling experiments. The results show that the prediction accuracy of the machine tool specific energy consumption model can reach 98.7%, and the roughness model can reach 96.8%. Later, according to the developed prediction models, the influence of milling parameters, surface hardness, and tool wear on the machine specific energy consumption and surface roughness is studied. Results show that in stainless steel milling, the most significant parameter for surface roughness is the machined surface hardness, while that for energy consumption is the feed per tooth. The machine specific energy consumption increases linearly with the increase of the tool wear and the machined surface hardness gradually. The proposed models are helpful to optimize the process parameters for energy-saving and high-quality machining of stainless steel. [ABSTRACT FROM AUTHOR]

Hot air fluidized bed drying combined with halogen lamp drying (HAFH) is an innovative hybrid drying technique for parboiled rice production that is more effective than the traditional parboiled rice production (TPP). HAFH can eliminate the steaming process, which is a complex process with high energy consumption, and can also provide a good-quality parboiled rice. The experimental results showed that HAFH achieved faster moisture removal and a higher grain temperature than TPP and the hot air fluidized bed drying technique without a halogen lamp (HAF). The parboiled rice quality and specific energy consumption (SEC) were differently influenced by the production factors (hot air temperature and halogen power) and their interactions. However, the HAFH provides good quality attributes (degree of gelatinization, head rice yield, whiteness index, incidence of white belly, and hardness) equal to those of TPP with a lower SEC in parboiled rice production. Moreover, HAFH generated starch gelatinization both inside and outside of rice grains. [ABSTRACT FROM AUTHOR]

Energy demand forecasting plays a key role in solving the majority of problems connected with determining the economic and energy development prospects. In view of high inertia and capital intensity of energy generation facilities, the changes in the energy consumption structure and rates should be considered for a sufficiently long-term future of no less than 15 years. This adds much difficulty to the development of such forecasts, because it is necessary to take into account the possible results of technological progress in different sectors of the economy and changes in its structure. The suggested approach to energy demand forecasting is based on the systems analysis methods. Energy consumers are disaggregated by economic sectors, country regions, energy carriers, and their utilization areas. As a result, it becomes possible to take into account the possible future technological and structural changes in the economy, its differences in different regions, mutual replacements of energy carriers, and energy saving. The most important feature of the approach is that it involves the separation of economic and energy variables. Economic variables determine the development scales of economic sectors, and energy variables determine the energy consumption intensities in them. The separation of variables helps obtain essentially more accurate forecasts owing to the possibility of taking into account the differences in the variation trends of these variables in the forecast period. For forecasting the economic variables, a nonlinear conditionally dynamic model of interrelations between the economy and energy is used. The energy variables are forecasted on the basis of their links with economic factors, e.g., with cumulative investments in the fixed capital of the considered economic sectors. The discussed approach was implemented as the totality of adaptive simulation models united into the EDFS computing system. The approach was repeatedly and quite successfully used to forecast the energy demand for an up to 10–20-year horizon in solving various problems. The gained experience has demonstrated the correctness of applying the approach for solving long-horizon forecast problems. To illustrate the capacities of the approach, the electric energy demand forecast for the period of up to 2040 for the basic version of the social and economic development of Russia's economy prepared on the basis of this approach is presented. [ABSTRACT FROM AUTHOR]

The effect of five cases of temperature-and-speed conditions in radial-shear rolling (RSR) of D16 alloy is analyzed. The temperature of the rod after each pass is obtained from the simulation results. With decrease in the heating temperature of the billet, the self-heating temperature of the rod during RSR increases. Depending on the selected temperature, rolling speed, reduction per pass, and rod dimensions, the temperature change relative to the initial heating can be more than 100°C. The length and volume of the back-end defect are calculated for each of the temperature-and-speed conditions. With increase in the elongation ratio, the length of the back-end defect increases, and its volume decreases. The smallest back-end defect is observed in rods produced gradually decreasing the rolling temperature in each pass (for a 6 m rod, the scrap losses are 2.2% of the volume of rolled metal). For one of the temperature-and-speed conditions, the specific deformation energy consumption that does not exceed 24–35% of the total energy consumption is obtained. The rods produced by RSR have better strength and plasticity (σB = 452–486 MPa, σy = 262–290 MPa, δ = 13.0–16.5%) than those required by the GOST 21488–97 State Standard. [ABSTRACT FROM AUTHOR]

A methodology for developing models for digitally describing the process of smelting a semi-product in an electric arc furnace (EAF) is presented. The developed models are shown to facilitate the efficient smelting of scrap in terms of obtaining the optimal temperature for efficiently carrying out the dephosphorization process while reducing energy consumption in online mode. [ABSTRACT FROM AUTHOR]

Specific energy consumption (SEC) also called energy intensity is one of the important aspects for lumber sawing sawmills since it represents the energy efficiency of the sawmill. Production, process, and energy data were gathered by visiting five sawmills out of which three sawmills had single sawing lines and two sawmills had double sawing lines. Sawmills with single and double sawing lines were selected in order to cover the different sawmill configurations. Data from sawmills 1, 2, 4, and 5 was used to develop an estimation model to estimate SEC of sawmill 3 based on the product, process, and system parameters. The independent variables that were included in the model were species, lumber sizes for the product, sawing time, maintenance schedule for the process, and motor horsepower, availability of resaw, and production line configuration for the system. Energy consumption of a motor on the demand side mainly depends on its capacity, operating hours, and load factor/efficiency ratio, and model 2 in this paper estimated SEC of a new sawmill from the product, process, and system parameters which represented the load factor/efficiency ratio when capacity and operating hours were known in the new sawmill. The product, process, and system parameters in model 3 represented motor capacity also along with the load factor/efficiency ratio and estimated SEC of a new sawmill. The developed regression models can be used to predict the sawing energy consumption of a new sawmill with reasonable accuracy. [ABSTRACT FROM AUTHOR]

Global water scarcity is one of the biggest human concerns in recent decades. Seawater desalination becomes the dominant way to access the new drinkable waters. The present study developed a heat pump-assisted humidification–dehumidification water desalination system. The designed system is equipped with a novel solar humidifier that works based on the free-flow solar water collectors. The effect of air flow rate and mode of the air circulation system on the performance of the designed system was experimentally investigated. The results reveal that raising the air flow rate improved water evaporation rate and the solar humidifier efficiency, while closing the air circuit led to a reduction in the evaporation rate. The maximum evaporation amount and water productivity were around 1.38 and 1 kg/h/m2 in the average solar irradiance of 877 W/m2. The closed-loop air circulation system resulted in a significantly higher effectiveness of dehumidification and produced higher desalinated water compared with the open-circuit mode. The lowest specific electrical energy consumption and the highest gained output ratio values of, respectively, 0.15 kWh/kg and 2.36 were observed at the air flow rate of 0.019 m3/s/m2 of solar humidifier when closing the air circulation system. [ABSTRACT FROM AUTHOR]

The basalt electric melting advantages in application of basalt fiber in industrialized construction and heat power engineering are shown. The results of thermodynamic calculations of the process of Kazakhstan basalt melting are given. The calculations have shown that in gaseous and condensed products of the process there are no harmful substances. Experiments on electric melting of basalt in a reactor with electromagnetic mixing of the melt were carried out. The prospects of electric melting of basalt and obtaining mineral fiber with the use of small-size module installations involving an electromagnetic reactor are shown. The specific energy consumption for obtaining a homogeneous basalt melt does not exceed 1.1 kW·h/kg, which is superior to the widely used SHF-reactors in which the specific energy consumption is several times higher. [ABSTRACT FROM AUTHOR]

Inert gases are valuable products that are widely used in industry. Their processing scheme includes several enrichment, purification, and separation stages of a Ne–He mixture (NHM). Primary enrichment of the NHM occurs in air-separation plants. Secondary enrichment uses a reflux condenser at liquid N2 temperature (~78 K). The impurity concentration at the reflux condenser outlet can be decreased by reducing the operating temperature. However, the specific energy consumption increases whereas the extraction coefficient is practically not affected if a vacuum pump is applied. A promising trend for reducing the cooling temperature is to use non-machine cold sources. The Ne extraction coefficient during rectification depends on the impurity (He) content in the waste gases. The main method for increasing the efficiency of Ne production installations is to use additional non-machine cooling of the rectification input stream. The adsorption installation for recycling Ne from He concentrate can be chilled using two coolants, i.e., Ne and liquid N2. The research showed that the specific energy consumption of the separation is 5–7 times greater to reach Ne temperature (28 K) than liquid N2 temperature (78 K). [ABSTRACT FROM AUTHOR]

Inert gases are in great demand by industry. Neon is produced as a by-product of air-separation plants in the form of a crude Ne–He mixture. Downstream Ne production technology includes several stages accomplished in separate installations. The Ne extraction coefficient and specific energy consumption per product unit were adopted as criteria for assessing the efficiency of plants in downstream Ne production technology. The primary enrichment stage of a Ne–He concentrate in rectification columns of air-separation plants was studied in the present work. The research showed that this stage had a characteristically low extraction coefficient of < 0.7. [ABSTRACT FROM AUTHOR]

Indole is a highly recalcitrant aromatic heterocyclic organic compound consisting of a five-membered nitrogen-containing pyrrole ring fused to a six-membered benzene ring. This study presents the results of the electro-chemical mineralization of indole in an aqueous solution using platinum-coated titanium (Pt/Ti) electrode. A central composite design was used to investigate the effect of four parameters namely initial pH (pH), current density ( j), conductivity ( k) and treatment time ( t) at 5 levels. Multiple responses namely chemical oxygen demand (COD) removal ( Y ) and specific energy consumption ( Y ) were simultaneously maximized and minimized, respectively, by optimizing the parameters affecting the mineralization of indole by using the desirability function approach. At the operating conditions of pH 8.6, j = 161 A/m, k = 6.7 mS/cm and t = 150 min, 83.8% COD removal with specific energy consumption of 36.3 kWh/kg of COD removed was observed. Ultra performance liquid chromatography, UV-visible spectroscopy, Fourier transform infrared spectroscopy and cyclic voltammetry of the indole solution were performed at the optimum condition of the treatment so as to report a plausible mechanism of indole degradation. Field emission scanning electron microscopy analysis of electrodes before and after treatment was performed for determining the changes on anode surface during the treatment. Thermal analysis of the solid residue (scum) obtained was also performed for exploring its disposal prospects. Present study shows that electro-chemical oxidation can be used for mineralization of nitrogenous heterocyclic compounds such as indole. [ABSTRACT FROM AUTHOR]

Water jet pulverization (WJP) is a recently proposed strategy in the reclamation of waste tire rubber (WTR). Aiming at improving the quality of the produced ground tire rubber (GTR), along with increasing the yield and efficiency of WJP, the present study focused on the multiresponse optimization of process parameters as working pressure of water jet (219.5-320.5 MPa), standoff distance between the jet orifice and WTR (98.9-351.1d) and transverse velocity of the orifice (597.7-1102.3 mm/min) in WJP using response surface methodology (RSM). A five-level three-factor central composite rotatable design by RSM was employed to statistically describe the main and interaction effects of process variables on the selective five responses. The predicted results by the regression models showed good agreements with the experimental data. In addition, an optimization was successfully carried out by a desirability function, in order to define the combination of process parameters that optimizes the quality evaluation of the produced GTR and minimizes the specific energy consumption in WJP. [ABSTRACT FROM AUTHOR]

Green bell pepper was dried under vacuum-assisted microwave drying condition and the process was optimized using response surface methodology. The effect of microwave power (100-300 W) and vacuum level (200-600 mm Hg) were observed on the responses, viz. green color ratio, rehydration ratio, hardness, apparent density ratio, drying time and specific energy consumption. A central composite face-centered design was used to develop predictive regression models for the responses. Analysis of variance showed that quadratic model best fitted the experimental data. The microwave power level had greater effect on the quality attributes of green bell pepper; nevertheless at higher vacuum level the dried products had better quality. The optimum drying conditions were determined to be 284.4 W microwave power, 600 mm Hg vacuum level and the optimized value of the responses were obtained as green color ratio of 80.70%, rehydration ratio of 10.75, hardness of 152.98 N, apparent density ratio of 76.02%, drying time of 78 min, and specific energy consumption of 6.57 MJ/kg. Validation experiment was carried out at derived optimum condition to verify the prediction and adequacy of the models. Close agreement between experimental and predicted values was obtained. [ABSTRACT FROM AUTHOR]

Statistical entropy analysis method is used to study an LNG plant operating on high-pressure cycle with precooling at -70°C. The degree of thermodynamic perfection and the plant-units-wise energy consumption distribution are determined by calculation and confirmed by experiment. It is shown that the plant can be perfected further by introducing a cascade precooling cycle into the plant circuit, whereupon the degree of thermodynamic perfection increases by 4.7% and the specific energy consumption decreases by 5%. [ABSTRACT FROM AUTHOR]

Due to the soar of the energy price and the environmental problems are becoming more and more serious, the energy consumption and efficiency of processes are becoming the focus of academia and industry gradually. Some significant researches on the energy consumption of machine tools have been performed. In most previous studies, material removal rate is treated as a comprehensive variable. However, it cannot offer the energy footprint for a machining process and provide the support for process planning which needs the information of cutting speeds, feed rates, and depth of cut. This paper presents an integrated model for predicting the specific energy consumption (SEC) of manufacturing processes. The dynamic characteristics of material-cutting power and influence of the machine tools, material of workpiece, and cutting parameters on the material-cutting energy are both taken into account in the model. The case study indicates that the model can be used to predict the SEC of machine tools conveniently under various machining conditions. At last, the validation is carried out in different machining processes; the accuracy and feasibility of the model was verified by the experimental results. [ABSTRACT FROM AUTHOR]

From time to time, science presents us with so-called "challenging problems," which may take a long time and several generations of scientists to solve. Certain problems remain unsolved for decades, such as the Fermat theorem, Poincaré conjecture, or entropy paradoxes. The longer it takes to solve the problem, the more unexpected becomes the fact of solving it, and not just in terms of making progress in the field, in which the problem was formulated, but for the benefit of the entire science in general. There are also smaller oddities, which people tend to ignore. But sometimes, finding solutions to seemingly small problems paves the way to overcoming some serious global challenges. [ABSTRACT FROM AUTHOR]

European steel producers need to increase energy efficiency and reduce CO emissions to meet requirements set by European policies. Robust indicators are needed to follow up these efforts. This bottom-up analysis of traditional energy and climate indicators is based on plant-level data from three Swedish steel producers with different product portfolios and production processes. It concludes that indicators based on both physical and economic production are interlinked with aspects both within and outside the company gates. Results estimated with partial least squares regression confirm that steel production has complex relationships with markets, societal context, and operational character of the industry. The study concludes that (i) physical indicators (based on crude steel production) may be useful at the process level, but not at the industry-wide level, (ii) the value added is not a reliable alternative since it cannot be properly estimated for companies belonging to larger international groups, and (iii) structural shifts may influence the results significantly and veil improvements made at the process level. Finally, harmonised system boundary definitions are vital for making indicators comparable between companies. The use of traditional indicators, as defined today, may lead to uninformed decisions at the company as well as policy levels. [ABSTRACT FROM AUTHOR]

A conveyor-belt dryer was developed using a combined infrared and hot air heating system that can be used in the drying of fruits and vegetables. The drying system having two chambers was fitted with infrared radiation heaters and through-flow hot air was provided from a convective heating system. The system was designed to operate under either infrared radiation and cold air (IR-CA) settings of 2000 W/m with forced ambient air at 30 °C and air flow of 0.6 m/s or combined infrared and hot air convection (IR-HA) dryer setting with infrared intensity set at 2000 W/m and hot at 60 °C being blown through the dryer at a velocity of 0.6 m/s or hot air convection (HA) at an air temperature of 60 °C and air flow velocity 0.6 m/s but without infrared heating. Apple slices dried under the different dryer settings were evaluated for quality and energy requirements. It was found that drying of apple (Golden Delicious) slices took place in the falling rate drying period and no constant rate period of drying was observed under any of the test conditions. The IR-HA setting was 57.5 and 39.1 % faster than IR-CA and HA setting, respectively. Specific energy consumption was lower and thermal efficiency was higher for the IR-HA setting when compared to both IR-CA and HA settings. The rehydration ratio, shrinkage and colour properties of apples dried under IR-HA conditions were better than for either IR-CA or HA. [ABSTRACT FROM AUTHOR]

This study was performed to determine the drying characteristics and final product quality of tomato slices dried at infrared radiation intensities of 1830, 2385, 2640, 2880, and 3165 W/m and at air velocities of 1.0, 1.5, and 2.0 m/s. A comprehensive analysis of dried products was performed on their drying kinetics, drying time, specific energy consumption, shrinkage, rehydration ratio, color, vitamin C, and lycopene. The results showed that drying time was prolonged with increasing air velocity while it was shortened with increasing infrared radiation intensity. The lowest energy consumption occurred at the air velocity of 1.0 m/s and at infrared radiation intensity of 2640 W/m. Shrinkage and rehydration ratio varied between 0.139 from 0.203 and 2.14 from 3.40 for all the drying conditions, respectively. Δ E values varied from 5.70 to 13.06. The contents of vitamin C and β-carotene in infrared dried tomatoes were decreased by 2-51 and 5-51 %, respectively, while there was a significant increase in lycopene content varying between 50 from 529 %. Totally, it was observed that infrared drying of tomato provided good nutrient retention and low cost of energy. Therefore, infrared radiation can be suggested in both nutritional and operational aspects in terms of drying tomato slices. [ABSTRACT FROM AUTHOR]

A numerical study of schemes for helium recovery from high-pressure natural gas using advanced gas separation membranes has been performed. It has been shown that the optimal scheme is a two-stage design with two recirculation circuits consisting of an ordinary separator in the first stage and a recirculation scheme as the second stage. [ABSTRACT FROM AUTHOR]

European iron and steel producers are working towards increased energy efficiency to meet requirements set by European policies such as the Energy Efficiency Directive. In this study, we show that the specific energy consumption (SEC), representing the iron and steel sector in the Odyssee energy efficiency index (ODEX)-the tool for policy evaluation recommended by the European Commission-is insufficient for capturing energy efficiency trends of European iron and steel production. European producers focus on niche markets, diversifying and specialising their set of products well beyond crude steel, which is the benchmark product for deriving the SEC. We compare the SEC with the more comprehensive Malmquist productivity index (MPI) methodology, which is calculated using data envelopment analysis (DEA) techniques. An evaluation of energy efficiency trends during 2000-2010 showed that the SEC overestimated energy efficiency improvements for European steel industries, while underestimating the improvements achieved by Swedish steel industries. A comparison between the SEC, the MPI/DEA approach, and energy intensity based on value added in the Swedish case provides further insight to the methodological differences between the approaches. We conclude that the approaches highlight different aspects of energy efficiency analyses and that the SEC is not sufficient for capturing the energy efficiency of steel industries. [ABSTRACT FROM AUTHOR]

This paper deals with kinematics, dynamics and power consumption analyses of a six-legged robot generating turning motions to follow a circular path. Direct and inverse kinematics analysis has been carried out for each leg in order to develop an overall kinematics model of the six-legged robot. It aims to estimate energy-optimal feet forces and joint torques of the six-legged robot, which are necessary to have for its real-time control. To determine the optimum feet forces, two approaches are developed, such as minimization of norm of feet forces and minimization of norm of joint torques using a least square method, and their performances are compared. The developed kinematics and dynamics models are tested through computer simulations for generating turning motion of a statically stable six-legged robot over flat terrain with four different duty factors. The maximum values of feet forces and joint torques decrease with the increase of duty factor. A power consumption model has been derived for the statically stable wave gaits to minimize the power requirement for both optimal foot force distributions and optimal foot-hold selection. The variations of average power consumption with the height of the trunk body and radial offset have been analyzed in order to find out energy-optimal foothold. A parametric study on energy consumption has been carried out by varying angular velocity of the robot to minimize the total energy consumption during locomotion. It has been found that the energy consumption decreases with the increase of angular velocity for a particular traveled distance. [ABSTRACT FROM AUTHOR]

Garlic slices were dehydrated by convective drying (CD) and by a combined method consisting of convective pre-drying followed by vacuum-microwave finishing drying (CPD-VMFD). Drying of garlic using VMFD led to samples with high values of lightness and slightly lower values of the coordinates a* and b*. The treatment CPD-VMFD significantly decreased the drying time from 630 min for CD to 49 min and contributed to an important energy saving compared with CD (54.4-86.3 %). The total drying time was shorter when vacuum microwaves were introduced earlier and microwave power was higher. The highest temperature (114 °C) was found for samples pre-dried to a moisture content of 60 % and then dried at 360 W while showing the lowest energy consumption (98 ± 1 kJ g). In general, the total antioxidant capacity increased after drying of garlic slices; however, the content of total phenolic compounds showed the opposite trend, and thus other compounds, such as allicin, should be involved in the antioxidant capacity of dried garlic. Garlic slices were CP dried until 30 % of moisture content followed by VMFD at 240 or 360 W showed the best results in terms of energy consumption and antioxidant capacity. [ABSTRACT FROM AUTHOR]

The effectiveness of various microwave-convective drying treatments was compared with convective drying to determine the most favourable treatments in terms of drying kinetics, specific energy consumption and dried product quality of grated carrots. The quality of the dried products differed among drying treatments depending on the microwave power level, pulse ratio and drying temperature. The intermittent microwave-convective drying at ambient temperature with a pulse ratio of 3.0 at 2.23 W g provided considerable savings in drying time and specific energy consumption when compared to convective drying and produced high-quality product with better physical (colour and texture) and sensory attributes for carrots. The intermittent microwave-convective drying conducted at lower drying temperature with relatively long power-off time resulted in a more stable and gentle drying process and could be preferred to produce high-quality products. [ABSTRACT FROM AUTHOR]

Under the condition of the designated collection ratio and the interfused ratio of mullock, to ensure the least energy consumption, the parameters of collecting head (the feed speed, the axes height of collecting head, and the rotate speed) are chosen as the optimized parameters. According to the force on the cutting pick, the collecting size of the cobalt crust and bedrock and the optimized energy consumption of the collecting head, the optimized design model of collecting head is built. Taking two hundred groups seabed microtopography for grand in the range of depth displacement from 4.5 to 5.5 cm, then making use of the improved simulated annealing genetic algorithm (SAGA), the corresponding optimized result can be obtained. At the same time, in order to speed up the controlling of collecting head, the optimization results are analyzed using the regression analysis method, and the conclusion of the second parameter of the seabed microtopography is drawn. [ABSTRACT FROM AUTHOR]

Rice milling operation is a very energy-intensive process. The major qualities of the rice which are taken into consideration while milling are the degree of milling and head rice yield. A laboratory abrasion polisher, modified by attaching a humidifying and cooling unit, was used to polish long-grain Pusa Basmati rice in order to optimize the polishing conditions. Polishing experiments were carried out using central composite design for a factorial with a central point, at different initial grain temperatures (5–25 °C) and milling chamber temperatures (11–25 °C) at a constant humidity level of 95 ± 2% for different time intervals. Models capable of predicting the quality of milled rice were developed using response surface methodology and used to determine optimum processing conditions. Responses such as degree of milling (DOM), broken content, and specific energy consumption were used to assess product quality. Optimum milling conditions of a minimum of 10% DOM, a broken content of 8%, and a specific energy consumption of 11 kJ/DOM were obtained at a milling chamber temperature of 11 °C, an initial grain temperature of 15 °C, and a milling period of 180 s. [ABSTRACT FROM AUTHOR]