Combined Power Research Articles

Particle size distribution of Japanese cedar chip converted from boards using a disc chipper and its relationships with disc rotation speed and board feed speed

The effects of disc chipper rotation speed and raw material feed speed on the particle size distribution of wood chips produced were investigated to develop an efficient technique for producing ideal sized chips for the stable operation of combined heat and power plants. The particle size distribution of wood chips was measured using a screening method and approximated to a Rosin–Rammler distribution to calculate the median of the chip. The results suggest that chip size decreased as the rotation speed increased from 560 to 720 rpm, but no clear effect of feed speed on the chip size was observed. The Rosin–Rammler equation was found to be appropriate to explain the size distribution of wood chips. Two types of screening sieves, woven wire mesh sieve and perforated plate sieve, were used for the screening. It was found that the woven wire mesh sieve may underestimate the size of the chip, although the Rosin–Rammler equation derived from the woven wire mesh sieve was able to be converted to the equation for the perforated plate sieve.

Why are some articles highly cited in applied linguistics? A bibliometric study

Abstract This study investigated factors influencing the citations of highly cited applied linguistics research over two decades. With a pool of 302 of the top 1% most cited articles in the field, we identified 11 extrinsic factors that were independent of scientific merit but could significantly predict citation counts, including journal-related, author-related, and article-related features. Specifically, the results of multiple linear regression models showed that the time-normalized article citations were significantly predicted by the number of authors, subfield, methodology, title length, CiteScore, accessibility, and scholar h-index. The remaining factors did not exhibit any statistical significance, including the number of references, funding, internationality, and geographical origin. The combined predictive power of all these factors (R²=.208, p<.05) verifies the role of nonscientific factors contributing to high citations for applied linguistics research. These results encourage applied linguistics researchers and practitioners to recognize the underlying forces affecting research impact and highlight the need for a reward system that exclusively favors sound academic practices.

Multi-orthogonal-oppositional enhanced African vultures optimization for combined heat and power economic dispatch under uncertainty

Multi-orthogonal-oppositional enhanced African vultures optimization for combined heat and power economic dispatch under uncertainty

Advanced anaerobic co-digestion of hydrothermally pretreated wheat straw: Process performance, techno-economic and life cycle assessment.

Hydrothermal and thermal-alkali pretreatment potential was investigated to enhance agro-wastes' anaerobic co-digestion (AcoD). The techno-economic (TEA) and life cycle assessment (LCA) of biogas upgrading (BioCNG) and energy generation via combined heat and power (CHP) processes for energy utilization were carried out to realize the environmental impacts and cost-effectiveness of the studied processes. Three AcoD conditions of untreated, hydrothermally (150°C, 60min) and thermal-alkali pretreated (1% NaOH, 150°C- 60min) wheat straw (WS) with food waste and cow manure were studied in semi-continuous mode for 340 days under variable organic loading rates (OLR, 1.25-3.75 gVS/L.d). At an OLR of 1.67 gVS/L.d and 45 days HRT, the methane yield and volatile solids removal in control digester were 231 mL/gVS and 39.7%, and in thermal-alkali pretreated digester were 302 mL/gVS and 53.3%, presenting an increase of 30% and 34% over control, respectively. The LCA and TEA of all three processes under 45 days of HRT operations were carried out. The environmental performance evaluation across various scenarios indicated that integrating pretreatment with the combined heat and power (CHP) process significantly lowered the global warming potential (GWP), outperforming the BioCNG process. In particular, hydrothermal pretreatment made the largest contribution to the reduction in GWP, achieving a value of -0.1935kg CO2-equivalent, primarily due to energy generation from the CHP process. In comparison, the BioCNG process recorded a GWP of -0.0377kg CO2-equivalent. This result demonstrates that the CHP process led to an 81% greater reduction in GWP than the BioCNG process. While the BioCNG process surpassed CHP in terms of economic performance, the hydrothermal pretreatment scenario proved to be financially the most advantageous, with a net present value (NPV) of $10.16 million, an internal rate of return (IRR) of 13%, and a shorter payback period (PBP) of 14 years.

Investigation on electric heat pump solutions for carbon reduction in an integrated energy system with the coal-fired combined heat and power unit

Investigation on electric heat pump solutions for carbon reduction in an integrated energy system with the coal-fired combined heat and power unit

Re-establishing and Elucidating the right operation strategy foundation for combined heat and power systems

The operational strategies of Following Thermal Load (FTL) and Following Electricity Load (FEL) are pivotal for combined heat and power systems (CHPs) across diverse research and application contexts. However, this study reveals a long-standing misapplication of the FEL/FTL strategy, leading to substantial global energy inefficiencies persisting for decades. Through rigorous mathematical deduction and counter-example analysis, this research highlights the inadequacies of the conventional FEL/FTL approach and advocates for its revision to enhance energy conservation. Subsequently, employing the corrected operational foundation, this study introduces comprehensive methodologies for deriving optimal strategy maps applicable to various CHPs. Considerations include prime mover type, power grid efficiency, and the minimization of wasted thermal energy. A case study demonstrates that our proposed methodology can result in a 12 % reduction in fuel consumption compared to conventional energy supply schemes. The redefined operational foundation for CHPs not only rectifies existing practices but also provides a correct reference for future research in this domain.

Techno-economic and environmental performance of hot dry rock for combined heat and power based on life cycle assessment

Techno-economic and environmental performance of hot dry rock for combined heat and power based on life cycle assessment

Simulation investigation of a Ka-band phase-locked klystron-type coaxial relativistic Cherenkov generator

To achieve coherent power combination of Ka-band high-power microwave (HPM), a phase-locked klystron-type coaxial relativistic Cherenkov generator (PKC-RCG), which combines the advantageous characteristics of weak dimensional sensitivity of RCG and low input power ratio of relativistic triaxial klystron amplifier (TKA), is proposed and investigated in this paper. The PKC-RCG is composed of two parts: a pre-modulation region adapted from TKA and an energy exchange region adapted from RCG. The pre-modulation region is used for initial speed modulation of intense relativistic electron beams (IREB), ensuring that the output frequency is consistent with the input frequency. The energy exchange region is used for deep clustering of the IREB and achieving efficient beam–wave energy conversion. Phase locking of the output HPM is accomplished through phase delivery of the modulated IREB. Specially designed reflectors and cascaded single-gap bunching cavities with active suppression of asymmetric TM mode are employed in the pre-modulation region to suppress energy coupling and achieve a lower input power ratio. Disk-loaded slow-wave structure with smooth inner conductor is employed in the energy exchange region to further decrease the dimensional sensitivity of RCG. By the proposed Ka-band PKC-RCG, an HPM with a power of 550 MW and a frequency of 29.0 GHz is obtained with ohmic loss being taken into account. Moreover, the input power ratio and phase-locking bandwidth of the proposed Ka-band PKC-RCG are −51.4 dB and 30 MHz, respectively.

Comprehensive assessment of organic Rankine cycles using renewables energy for combined power and heat generation in a badminton stadium

Comprehensive assessment of organic Rankine cycles using renewables energy for combined power and heat generation in a badminton stadium

Comprehensive analysis and optimization of an efficient combined power and refrigeration cycle suitable for recovering low/mid-grade waste flue gas

To effectively recover low/mid-grade waste flue gas and provide larger refrigeration capacity, an efficient combined power/refrigeration cycle only using ammonia water as the working fluid is proposed and studied. Parametric analysis is conducted from the perspectives of thermodynamics, exergoeconomics, and environment, the results demonstrate that the low/mid-grade waste flue gas within a wide range of temperature can be sufficiently recovered by the proposed cycle, and the cycle performance is significantly affected by the turbine inlet pressure, work/basic concentration and separation temperature of work solution. Based on the heat source condition of 300°C/10 kg·s-1, the results of single-objective optimization show that the maximum effective exergy efficiency, reduction amount of CO2 emission and waste heat recovery ratio that can be achieved are 0.5989, 262 kg/h and 0.97 respectively, and the achievable minimum unit cost of produced exergy is 8.432 $·GJ-1. Besides, the multi-objective optimization indicates that the optimal comprehensive thermodynamic efficiency is 0.5458 with net power output of 372.5 kW and larger refrigeration capacity of 545.7 kW, and the associated effective exergy efficiency, unit cost of produced exergy, reduction amount of CO2 emission and waste heat recovery ratio are 0.5701, 9.187 $/GJ, 258.3 kg/h and 0.9574, respectively.

Particle manipulation under X-force fields.

Particle manipulation is a central technique that enhances numerous scientific and medical applications by exploiting micro- and nanoscale control within fluidic environments. In this review, we systematically explore the multifaceted domain of particle manipulation under the influence of various X-force fields, integral to lab-on-a-chip technologies. We dissect the fundamental mechanisms of hydrodynamic, gravitational, optical, magnetic, electrical, and acoustic forces and detail their individual and synergistic applications. In particular, our discourse extends to advanced multi-modal manipulation strategies that harness the combined power of these forces, revealing their enhanced efficiency and precision in complex assays and diagnostic frameworks. The integration of cutting-edge technologies such as artificial intelligence and autonomous systems further enhances the capabilities of these microfluidic platforms, leading to transformative innovations in personalized medicine and point-of-care diagnostics. This review not only highlights current technological advances, but also forecasts the trajectory of future developments, emphasizing the escalating precision and scalability essential for advancing lab-on-a-chip applications.

Solving economic emission dispatch of combined heat and power units problem using enhanced Tasmanian devil optimization strategy in power systems

ABSTRACT Economic load dispatch (ELD) is a general procedure to distribute essential loads among the available generation units to minimize operational costs. Different problems presented in the ELD are generated because of inequality and equality constraints of the system. The double objective-based combined economic emission dispatch (CEED) issues presented in the power system are considered for the environmental impacts and accumulated by the gaseous pollutants emission in the fossil-fueled power plants. Moreover, the purpose and importance of the multi-objective combined heat and power economic emission dispatch has to be considered since the co-generation system with two major objectives like fuel cost and emission mass, must be reduced. Thus, the non-convex and non-linear objective functions require the best optimization technique to resolve the issues. Hence, this paper presented an efficient CEED framework by developing novel optimization strategy. The enhanced Tasmanian devil optimization (ETDO) algorithm is developed in this work by enhancing the Tasmanian devil optimization (TDO) algorithm through the parameter regularization, and enhanced fitness function. Various complex benchmark datasets are considered in this work for the experimental verification. In addition, various standard power system problems of CEED are rectified with the help of the proposed ETDO to attain better efficacy than the previous systems. The objective function of the proposed ETDO-based heat and power unit optimization in the CEED problem is to reduce the overall fuel cost and emission. The performance analysis of the developed ETDO algorithm is varied based on iterations. Overall, the cost function analysis is performed using the developed model that shows as 16.3%, 8.8%, 12.7%, and 6.8% improved than HGSO, ESO, EVO, and TDO at the 50th iteration. This experimental analysis shows that the proposed ETDO for solving CEED issues performs well in complex environments and large-scale emission applications. Further experiments on the proposed ETDO are held by varying the total heat and power units to measure the reliability and robustness of the system.

Use of Biogas in Gas Turbines for the Production of Heat and Electricity

In the modern developed countries of the world, the main part of the extracted fuel and energy resources is spent on the production of electricity and heat of low and medium potential. In Ukraine, the biomethane production potential is estimated at 7.8 billion m3/year, which is 25 % of the current natural gas consumption in the country. The infrastructure of Ukraine is ready for transportation and energy use of biomethane, as biomethane is a complete analogue of natural gas. When storing organic waste ("bio-waste") – for example, the organic part of household waste - biogas, a mixture of methane and carbon dioxide, is released. This gas is a high-quality fuel for gas engines or gas turbines - just like methane gas produced from biomass in sewage treatment plants. Biogas can replace fossil fuels and is also characterized by its CO2 neutrality. Biogas can be burned on-site with little to no processing to heat buildings and power boilers or even the reactor itself. Biogas can be used for combined heat and power generation, can be simply converted to electricity using an internal combustion engine, fuel cells or gas turbine, with the resulting electricity being used on-site or sold into the electricity grid. Taking into account the advantages of using biogas, as well as the price policy for natural gas, the study carried out a calculation of the thermal scheme of the state district power plant. Natural gas is used as the main fuel, biogas was chosen for comparison. The specific heat of combustion of biogas is almost half that of natural gas. When operating on biogas, the efficiency of a gas turbine installation is 8.5 % lower, and that of a steam-gas installation is 7.5 % lower than on natural gas. Since 1000 m³ of natural gas is equivalent to 1,00 m³ of biogas, a biogas accounting factor has been introduced. On the basis of the relevant research, conclusions were drawn regarding the use of biogas as an alternative to natural gas. The relevance of the use of biogas for the production of heat and electricity is to provide a promising source of electricity and reduce carbon dioxide emissions.

Developmental validation of a novel all-in one assay of X chromosomal multi-insertion/deletion loci for forensic genetics

Multi-insertion/deletion polymorphisms (Multi-InDels), as the novel genetic markers, show great potential in forensic research. Whereas, forensic researchers mainly focus on the multi-InDels on the autosomes, which can provide relatively limited information in some complex paternity cases. In this study, a novel X chromosomal multi-InDel multiplex amplification system was designed, containing 22 multi-InDels and one STR locus on the X chromosome. In order to verify the applicability and effectiveness of the novel system, the sensitivity, species specificity, repeatability, stability, and precision of the panel were verified. The results showed that the novel developed multiplex amplification system could still obtain complete allele profile at 62.5pg of template DNA and showed good tolerance to six common inhibitors. Meanwhile, the analyses of case samples showed that the system performed well on biological samples commonly found in forensic cases. The combined power of discrimination for males and females in the Guizhou Han population was greater than 0.999999999. Besides, the combined mean exclusion chance of these 23 loci exceeded 0.9999 in the trios and the duos. In conclusion, the multiplex amplification system is sensitive, precision, reproducible, and informative, which could be used as a high-efficient tool for complex kinship identification and personal identification.

Response of Soil Detachment Capacity to Hydrodynamic Characteristics Under Different Slope Gradients

The mechanism of soil detachment on steep slopes is obviously different from that on gentle slopes. However, the slope effect of soil detachment remains unclear. The objective of this study was to quantify the slope effect of soil detachment capacity at the varying hydrodynamic characteristics. In this study, the soil detachment capacity (Dc) on clay loam and hydrodynamic characteristics were measured by conducting the runoff scouring experiments at 10 slope gradients (1.7–57.7%) and 5 unit flow discharges (0.022–0.089 m2·min−1). The results showed that the relationships between Dc and hydrodynamic parameters were affected by slope gradient. Based on the optimal functional relationship, the hydrodynamic characteristics (flow velocity, flow shear stress, stream power, unit stream power, and unit energy) calculated by maximum and minimum Dc in this study changed by 19.91–95138.10%, and the Dc calculated by the maximum and minimum hydrodynamic characteristics could differ by up to nine orders of magnitude. Overall, the power function of hydrodynamic parameters was superior to the linear function in different slope gradients. The stream power was the best predictor for Dc compared with other hydrodynamic parameters. For all combinations of slope gradients, the adjusted coefficient of determination (Adj. R2) of the power relationship between Dc and stream power was 9.41–27.40% higher than it was between Dc and other hydrodynamic parameters. The coefficient and index of power function for different hydrodynamic parameters showed a trend change with increasing slope gradient, indicating that there was a slope effect on Dc. Further analysis found that Dc could be well predicted using a power combination equation of slope gradient, flow velocity, and flow depth (Adj. R2 = 0.96). This study helps to better understand the mechanism of soil detachment and emphasizes that the slope effect should be considered when establishing a soil detachment equation.

Thermodynamic integration in combined fuel and power plants producing low carbon hydrogen and power with CCUS

Demand for low-carbon sources of hydrogen and power is expected to rise dramatically in the coming years. Individually, steam methane reformers (SMRs) and combined cycle gas power plants (CCGTs), when combined with carbon capture utilisation and storage (CCUS), can produce large quantities of on-demand decarbonised hydrogen and power respectively. The ongoing trend towards the development of CCUS clusters means that both processes may operate in close proximity, taking advantage of a common infrastructure for natural gas supply, electricity grid connection and the CO2 transport and storage network. This work improves on a previously described novel integration process, which utilizes flue gas sequential combustion to incorporate the SMR process into the CCGT cycle in a single “combined fuel and power” (CFP) plant, by increasing the level of thermodynamic integration through the merger of the steam cycles and a redesign of the heat recovery system. This increases the 2nd law thermal efficiency by 2.6% points over un-integrated processes and 1.9% points the previous integration design. Using a conventional 35% wt. monoethanolamine (MEA) CO2 capture process designed to achieve two distinct and previously unexplored CO2 capture fractions; 95% gross and, 100% fossil (CO2 generated is equal to the quantity of CO2 captured). The CFP configuration reduces the overall quantity of flue gas to be processed by 36%–37% and increases the average CO2 concentration of the flue gas to be treated from 9.9% to 14.4% (wet). This decreases the absorber packing volume requirements by 41%–56% and decreases the specific reboiler duty by 5.5% from 3.46–3.67 GJ/tCO2 to 3.27–3.46 GJ/tCO2, further increasing the 2nd law thermal efficiency gains to 3.8%–4.4% points over the un-integrated case. A first of a kind techno economic analysis concludes that the improvements present in a CO2 abated CFP plant results in a 15.1%–17.3% and 7.6%–8.0% decrease in capital and operational expenditure respectively for the CO2 capture cases. This translates to an increase in the internal rate of return over the base hurdle rate of 7.5%–7.8%, highlighting the potential for substantial cost reductions presented by the CFP configuration.

Influence of urban landscape pattern on summer surface temperature and its spatial scale effects

Urban planning is pivotal in understanding how urban landscapes influence land surface temperature (LST) across various spatial scales. Using Landsat 8 OLI_TIRS images, we studied the spatial heterogeneity of LST in Hefei city of Anhui province, China. The results show that landscape pattern index (LSPI) can explain the spatial distribution of LST, remote sensing indices such as modified normalized difference water index (MNDWI) and normalized difference vegetation index (NDVI), play dominant roles in LST, and the explanatory power is stronger at small scales. As the spatial scale decreased, the explanatory power of NDVI and Built-land proportion on LST increases. The combined explanatory power of water and woodland on LST is more significant than the individual effect. When the proportion of Built-up land exceeds 60%, increasing the proportion of water and woodland can reduce the LST. This study provides insights to mitigate urban heat island (UHI) effect in urban planning.

Islam And Nationalism In Indonesia: Kh Maimun Zubair's New Interpretation In Tafsir Safinah Kalla Saya'lamun

This article discusses the relationship between Islam and nationalism in Indonesia, highlighting the important role of Islam in maintaining the integrity of the Republic of Indonesia through the spirit of nationalism. The combined power of religion and nationalism is a strong foundation to unite a diverse nation. This struggle does not only come from nationalists, but also from religious figures, one of whom is KH Maimun Zubair. He often voiced the importance of the national spirit in his lectures, in line with his work in politics through the United Development Party (PPP). This research uses the literature method with an analytical descriptive approach and the sociology of knowledge as an analytical tool. The main focus is the tafsir Safinah Kalla Saya'lamun Fi Tafsir Syaikhina Maimun, by his student Ismail al-Ashcholy, which summarizes the study of Tafsir al-Jalalain. KH Maimun Zubair asserts that nationalism is formed through the bonds of long residence, ethnic mixing, and migration, reflecting the principle of unity without discrimination, as taught since the time of the Prophet. According to him, all humans are equal in the eyes of Allah, and the only difference is the level of piety.

Development and validation of a multiplex panel with 232 microhaplotypes and software for forensic kinship analysis.

In this study, we developed and validated a novel microhaplotype (MH) panel, the FGID Microhaplotype Kit, which contains 232 loci and was specifically designed for forensic kinship analysis. The performance of the panel was evaluated through rigorous testing that included sensitivity, species specificity, inhibitor resistance, uniformity, stability, accuracy and mixture deconvolution. The results showed that the kit is capable of reliably detecting all loci with minimal DNA input. It showed high species specificity for 12 non-human DNA samples and resistance to common inhibitors. In addition, forensic statistical analysis revealed a combined discriminatory power (cDP) of 1-1.68e-223 and superior combined exclusion power for duo and trio cases compared to standard STR panels. The panel was also tested for kinship analyzes with simulated and real pedigree samples and showed significantly higher likelihood ratios (LR) for detecting relationships between parents and offspring, full siblings, half siblings and first cousins, especially for more distant kinship types where conventional STR panels have difficulties. Using the FGID kinship software with the MH panel significantly improved the accuracy of kinship analysis, allowing even closely related individuals to be effectively discriminated while reducing the number of false negatives. In addition, principal component analysis (PCA) showed that the panel can distinguish the major world populations and East Asian subpopulations. Taken together, these results suggest that the FGID Microhaplotype Kit and associated software provide an efficient and accurate solution for forensic kinship analysis that offers better discriminatory power and reliability than traditional STR-based methods.

Fully Polarized Wideband Omnidirectional RF Harvester with Highly Efficient DC Power Combination

In this work, an omnidirectional RF energy harvester with wideband coverage (1.5–2.7 GHz), all-polarization, and high-efficiency DC combining is proposed. The harvester integrates six microstrip rectenna elements with varying directions and polarizations. The harvester strategically combines six microstrip rectenna elements with different orientations and polarizations to enhance the stability of omnidirectional energy harvesting. The rectifier employs impedance compression matching techniques, incorporating open-circuited and short-circuited transmission lines to achieve a compact, broadband rectification. Experimental results show that the rectifier maintains an RF-to-DC conversion efficiency exceeding 50% within a bandwidth of 1.5 GHz to 2.7 GHz at an input power of 0 dBm, achieving a maximum efficiency of 62%. The maximum DC-combining efficiency of the rectifier array reaches 92%. These findings indicate that the harvester performs effectively with RF energy of all polarizations from various directions.