Search Results (19)

Successfully breeding high-yield, lodging-resistant hybrid rice varieties is critical for ensuring food security. Two-line hybrid rice system plays an essential role in rice breeding, and 1892S, an important two-line sterile line, has contributed significantly to the development of over 100 hybrid rice varieties with superior agronomic traits, including lodging resistance. Despite its importance, a comprehensive understanding of the genomic basis underlying these traits in 1892S has been lacking due to the limitations of short-read sequencing technologies. To address this gap, we utilized advanced telomere-to-telomere (T2T) genome assembly techniques to generate a high-quality, gap-free genome of 1892S—the final genome comprises 12 complete chromosomes with 40,560 protein-coding genes. Comparative genomic analysis identified multiple known lodging resistance genes, including SD1, Sdt97, SBI, OsFBA2, APO1, and OsTB1, with unique allelic variations that may enhance resistance. The pan-genome analysis identified 2347 strain-specific genes in 1892S, further supporting its unique genetic advantages. This study represents the complete T2T genome assembly of a two-line sterile line and provides novel insights into the genetic foundation of lodging resistance in hybrid rice. This study highlights the genetic potential of 1892S in hybrid rice breeding and provides a model for the genomic analysis of other two-line sterile lines, offering valuable insights for improving in hybrid rice, including traits lodging resistance, yield stability, and adaptability, which are crucial for global food security. Full article

Music can evoke powerful, positive, and meaningful experiences, but how does its potential to evoke such experiences come about? Listening to the music itself is critical, but referents (the thoughts, ideas, events, and affects associated with the music) are also relevant. We found a lack of understanding in the literature regarding the processes through which music evokes meaning through referents. To address this lacuna, we built on modern conceptions of framing theory. The following four framing processes were proposed, with each acting on different time scales (shortest [S] to longest [L]), and with an increasingly top-down [T] influence: (1) fluency [S]—the ease with which the accompanying information (about the music) can be mentally processed, with easy-to-process material leading to ‘increased preference/positive evaluation of the music’ [IPPE]; (2) facilitation—the content of the messaging directly influences IPPE, for example, when referring to the beauty of the music or the talent of the composer; (3) affiliation—when social influences imbue the music with meaning; and (4) fit [L, T]—when the other processes lead to long-term personal and cultural IPPE through norms and habits. Together, these processes can be applied to provide a comprehensive account of how musical meaning and preferences are developed. Three case studies show how these processes can be applied to the extant literature: why negatively framed music only has a relatively small (negative) impact on IPPE; why adding crowd sounds to recorded music only has a small effect; and how ‘labels’ such as Beethoven and Mozart become established and then impose top-down influence on music’s meaning. Full article

This research was conducted to evaluate and compare the efficiency of the modern external type thrust bearing cooling system (TBCS) with plate-type heat exchangers (PTHEs) applied as an alternative to standard design external type TBCS with shell-and-tube heat exchangers (STHEs) in a 180 MW large hydro power plant by experimental methods. Although similar studies are available in the literature, there is no comprehensive study on the effects of different parameters on performance and other plant parameters. The main parameters examined in the study are the cooling rate, oil temperature difference, average pad temperature (APT), and generator winding temperature. The tests were carried out over the range of 144–150.1 MW unit loads, 580–1317 L/min water flow rates, and 998–1411 L/min oil circulation flow rates. The results showed that the APT can only be reduced up to 73.4 °C at 1411 L/min oil circulation flow rate by 252.6 kW cooling, the optimum oil circulation flow rate is 1195 L/min, APT can be reduced by 1.7 °C and the maximum winding temperature by 1.3 °C when external type TBCS with PTHEs is used, and structural changes must be made in the thrust bearing design to provide further decrease in pad temperature. Full article

Polysaccharide-based nanoformulations with tailored hydrophobic properties have become a frontier in nanomedicine applications. Herein, highly hydrophobicized hydroxyethyl starch (HES) conjugates were synthesized by grafting stearic acid (SA) with HES via a carbodiimide-mediated reaction. A detailed NMR characterization of HES and the conjugates was studied to obtain structural information. The grafting ratio of the stearate-HES (St-HES) conjugates was determined from ¹H NMR spectra as 29.4% (St-HES29.4) and 60.3% (St-HES60.3). Thermal analyses and X-ray diffractograms suggested an entire transition from amorphous HES to a semicrystalline (St-HES60.3) character upon increasing the degree of grafting. Both conjugates, St-HES29.4 and St-HES60.3, were able to form self-assembled particles with a diameter of 130.7 nm and 152.5 nm, respectively. SEM images showed that the self-aggregates were mostly spherical in shape. These conjugates can be employed to entrap highly hydrophobic drugs with an increased encapsulation efficiency and loading capacity. Full article

Increasing production of poultry litter, and its associated problems, stimulates the need for generating useful energy in an environmentally friendly and efficient energy system, such as the use of shell-and-tube heat exchangers (STHE) in a fluidized-bed combustion (FBC) system. A holistic approach which involves the integration of the First Law of Thermodynamics (FLT) and Second Law of Thermodynamics (SLT) is required for conducting effective assessment of an energy system. In this study, the STHE designed by the CAESECT research group, which was integrated into the lab-scale FBC, was investigated to determine the maximum available work performed by the system and account for the exergy loss due to irreversibility. The effects of varying operating parameters and configuration of the space heaters connected to the STHE for space heating purposes were investigated in order to improve the thermal efficiency of the poultry litter-to-energy conversion process. Exergy and energy analysis performed on the STHE using flue gas and water media showed higher efficiency (75–92%) obtained via energy analysis, but much lower efficiency (12–25%) was obtained when the ambient conditions were factored into the exergy analysis, thus indicating huge exergy loss to the surroundings. From the obtained experimental data coupled with the simulation on parallel arrangement of air heaters, it was observed that exergy loss increased with increasing flue gas flow rate from 46.8–57.6 kg/h and with increasing ambient temperature from 8.8 °C to 25 °C. To lower the cost of STHE during final design, a larger temperature difference between the hot and cold flue gas is needed throughout the exchanger, which further increases the exergetic loss while maintaining an energy balance. In addition, this study also found the optimal conditions to reduce exergy loss and improve energy efficiency of the designed STHE. This study shows the possibility to evaluate energy systems using integration of exergy and energy analysis. Full article

In this paper, the fabrication and optimization of a spiral-tube heat exchanger (STHE) were considered for improving the heat transfer rate and efficiency of traditional instantaneous water heaters. The large number of instantaneous water heaters exported from the customers of the “Garman Gas Toos” company, which was mainly due to corrosion and leakage, imposed a lot of cost and credit reduction for this company. The high energy consumption was the second reason that justified working on a new STHE. The main innovation of this research is the design and construction of a new heat exchanger with a smaller size and higher efficiency with the help of identifying the factors affecting its efficiency and heat transfer rate. In order to optimize the responses, three variables were considered, including fin number (per unit area), exhaust outlet diameter, and water flow rate. Implementing face-centered central composite design (CCD), the proposed levels of factors and the corresponding response variables were measured in the “Garman Gas Toos” laboratory. Using the design of experiments (DoE), the effects of the three factors and their mutual interaction effects were evaluated. Response surface methodology (RSM) was devised to build a prediction model and obtain the values of the factors for which the responses were optimal. Based on the results, optimum conditions for the STHE were found to be an exhaust diameter of 4 cm and a water flow rate of 6 L/min coupled with six fins. At this optimal point, the values of efficiency and heat transfer rate, as response variables, were obtained as 85% and 8480 W, respectively. Full article

Collective-owned construction land (CCL) marketization is an important driving force for the rapid development of China’s rural economy and society. Recognizing the trends and logic of its institutional changes is important for better understanding the central-local interrelation and the new-round CCL reform. Throughout the process of rural land reform since China’s reform and opening up, together with the unified policy guidance from the central government, the diversity of local practices and the trend of convergence in the development process deserve attention. Based on the institutional isomorphism theory, this paper analyzes the evolution of the CCL system in Shunde, Guangdong Province, and Wujiang, Jiangsu Province, since the 1990s, empirically demonstrating the trend of convergence based on diversity and exploring the underlying influencing mechanisms. The study finds that the evolutionary practice is characterized by the trend of ephemeral convergence represented by the shared cooperative and the land reservation reform and that of coeval convergence represented by the construction land nationalization. Top-down coercive pressure, horizontal imitative learning pressure, and governance-embedded normative pressure jointly shape the evolutionary convergence. This paper argues that the diversity of local experiments should be allowed and encouraged based on local characteristics. Policy flexibility should be further considered by the central government when formulating uniform policies for local adaptability. Full article

Plate Heat Exchanger (PHE) and Shell and Tube Heat Exchanger (STHE) with identical heat transfer areas and material characteristics are proposed and a comparative thermal and economic comparative analysis is carried out on both exchangers. Ag-water nanofluid is used at low concentrations (0, 2.5, 5, 10 mg/L), flow rates (2, 5, and 8 L/min), and inlet temperatures (36, 46, and 56 °C) as hot flow and the heat transfer coefficient (U), electrical power consumption of the pump, and costs per unit of average U value are considered as the calculated parameters for each heat exchanger in co-current and counter-current flows. The results revealed that PHE generates a higher U value compared to the STHE under different Ag-water nanofluid concentrations. This is due to the existence of grooves on the plates of PHE which generates turbulent flow. The impact of nanofluid concentration on U is negligible for lower concentrations in both PHE and STHE. It is also found that the nanofluid flow rate has the highest impact on the U value, just like conventional fluid. Besides, even though counter-current flow increases the U values for both PHE and STHE, the flow pattern has a higher impact on the U value of PHE than that of STHE. For both PHE and STHE, increasing the nanofluid flow rate enhances the amount of U. However, the effect of flow rate on the U value of PHE is greater than that of the STHE. It is also shown that throughout the entire experimental temperature domain, PHE has had higher performance than STHE, and as the fluid temperature increased from 36 to 56 °C, there was a slight increase in the overall heat transfer of both PHE and STHE. Furthermore, for the same flow rate, both PHE and STHE had almost the same pump power consumption, and increasing the nanofluid flow rate from 2 L/min to 8 L/min promoted the electrical power consumption of the pump. Finally, we found that the costs per unit of heat transfer coefficient for PHE are significantly lower than STHE. The presented results also indicated that using a vortex generator at the inlet of STHE tubes, to form turbulent flow, increases the U values of STHE for both co-current and counter-current flows but these U values are lower than the corresponding U values of PHE. Small plates gap in PHE structure cause higher fluid flow velocities and create a chain-like structure of nanoparticles (NPs) between PHE’s plates (especially at higher nanofluids concentrations). Full article

Recent advances in hand gesture recognition have produced more natural and intuitive methods of controlling unmanned aerial vehicles (UAVs). However, in unknown and cluttered environments, UAV motion planning requires the assistance of hand gesture interaction in complex flight tasks, which remains a significant challenge. In this paper, a novel framework based on hand gesture interaction is proposed, to support efficient and robust UAV flight. A cascading structure, which includes Gaussian Native Bayes (GNB) and Random Forest (RF), was designed, to classify hand gestures based on the Six Degrees of Freedom (6DoF) inertial measurement units (IMUs) of the data glove. The hand gestures were mapped onto UAV’s flight commands, which corresponded to the direction of the UAV flight.The experimental results, which tested the 10 evaluated hand gestures, revealed the high accuracy of online hand gesture recognition under asynchronous detection (92%), and relatively low latency for interaction (average recognition time of 7.5 ms; average total time of 3 s).The average time of the UAV’s complex flight task was about 8 s shorter than that of the synchronous hand gesture detection and recognition. The proposed framework was validated as efficient and robust, with extensive benchmark comparisons in various complex real-world environments. Full article

The web we use today has seen many iterations over the years since the original concept of the World Wide Web was introduced in early 1990s.The first emergence of the web was called the static web or Web 1.0, which was read-only. A further iteration of the web then came along and was called the Social Web or Web 2.0, which was interactive in nature and the users could do more than read static pages. This was readable and writable, and saw the emergence of numerous social platforms. Web 3.0 offers an unmediated read–write web, or, to put it another way, a decentralized Internet. This paper provides a brief idea of how the journey of the web has so far transitioned from Web 1.0 through Web 2.0 and now onto Web 3.0, and what all lies ahead in future with emerging technologies and Web 3.0. Full article

The vegetation of the Qinghai-Tibet Plateau (QTP), China, is diverse and sensitive to climate change. Because of extensive grassland degradation in the QTP, several ecological restoration projects, which affect the livestock population, have been implemented in the QTP. Although many studies have reported the impacts of climate change on vegetation in the QTP, our knowledge on the impacts of both climate change and livestock on vegetation remains very limited. Here, we investigated the impacts of climate change and livestock population on vegetation growth by using the annual maximum normalized difference vegetation index (NDVI_max) and growing-season climate data from 1981 to 2019. We analyzed the relationship between NDVI_max and climate and livestock population using the modified Mann-Kendall trend Test and Pearson correlation analysis. For the entire QTP, NDVI_max had a two-phase trend, with a slow rise during 1981–2000 and a rapid rise during 2000–2019. Overall, NDVI_max in the QTP increased and decreased in 63.7% and 6.7% of the area in 2000–2019. In areas with significant changes in NDVI_max, it was strongly correlated with relative humidity and vapor pressure. The small positive trend in NDVI_max during 1981–2000 was influenced by warmer and wetter climate, and the overgrazing by a large population of livestock slowed down the rate of increase in NDVI_max. Livestock population for Qinghai and Tibet in recent years has been lower than in the 1980s.The warmer and wetter climate and substantial drops in the livestock population contributed to large recovery in vegetation during 2001–2019. Vegetation degradation in Qinghai during 1981–2000 and central-northern Tibet during 2000–2019 was driven mainly by drier and hotter climatic. Although 63.7% of the area in the QTP became greener, the vegetation degradation in central-northern Tibet should not be ignored and more measures should be taken to alleviate the impact of warming and drying climate. Our findings provide a better understanding of the factors that drove changes in vegetation in the QTP. Full article

In the past few decades, water and air were commonly used as working fluid to evaluate shell and tube heat exchanger (STHE) performance. This study was undertaken to estimate heat transfer coefficients and evaluate performance in the pilot-scale twisted tube-based STHE using the flue gas from biomass co-combustion as working fluid. Theoretical calculation along with experimental results were used to calculate the specific heat of flue gas. A simplified model was then developed from the integration of two heat transfer methods to predict the overall heat transfer coefficient without tedious calculation of individual heat transfer coefficients and fouling factors. Performance including water and trailer temperature, heat load, effectiveness, and overall heat transfer coefficient were jointly investigated under variable operating conditions. Results indicated that the specific heat of flue gas from co-combustion ranging between 1.044 and 1.338 kJ/kg$·$K while specific heat was increased by increasing flue gas temperature and decreasing excess air ratio. The developed mathematical model was validated to have relatively small errors to predict the overall heat transfer coefficient. A flue gas mass flow rate of 61.3–98.8 kg/h, a water flow rate of 13.7–14.1 L/min, and a parallel arrangement of two water-to-air heaters in an empty trailer were found to be optimal conditions for space heating purpose. In addition, a lower poultry litter feeding rate decreased heat loss of flue gas and increased heat gain of water, while a lower water flow rate also provided a lower maximum possible heat transfer rate with a higher actual heat transfer rate to quickly achieve heat equilibrium that ultimately improves the performance. This study demonstrates the possibility of collecting residual heat from the flue gas using the pilot-scale STHE system while outlining a systematic approach and process for evaluating its performance. Full article

The paper presents the results of research on liquid flow maldistribution in the shell side of a shell-and-tube heat exchanger (STHE). This phenomenon constitutes the reason for the formation of the velocity reduction area and adversely affects heat transfer and pressure drop. In order to provide details of the liquid distribution in STHE, two visualization methods were utilized. First, computational fluid dynamics (CFD) code coupled with the k-ε model and the laser-based particle image velocimetry (PIV) technique was applied. The tests were carried out for a bundle comprising 37 tubes in an in-line layout with a pitch d_z/t = 1.5, placed in a shell with D_in = 0.1 m. The STHE liquid feed rates corresponded to Reynolds numbers Re_in equal to 16,662, 24,993, and 33,324. The analysis demonstrated that the flow maldistribution in the investigated geometry originates the result of three main streams in the cross-section of the shell side: central stream, oblique stream, and bypass stream. For central and oblique streams, the largest velocity reduction areas were formed in the wake of the tubes. On the basis of the flow visualization, it was also shown that the in-line layout of the tube bundle helps to boost the wake region between successive tubes in a row. Additionally, unfavorable vortex phenomena between the last row of tubes and the lower part of the exchanger shell were identified in the investigations. The conducted studies confirmed the feasibility of both methods in the identification and assessment of fluid flow irregularities in STHE. The maximum error of the CFD method in comparison to the experimental methods did not exceed 7% in terms of the pressure drops and 11% in the range of the maximum velocities. Full article

Recently, the Senegalese people have learned to speak more openly of their history. But, as late as the 1980s—the years of my youth and early schooling—the wounds of colonialism were still fresh. I contend that slavery had been so powerful a blow to the Senegalese ethos that we—my family, friends, and schoolmates—did not speak about it. The collective trauma and shame of slavery was apparently so powerful that we sought to repress it, keeping it hidden from ourselves. We were surrounded by its evidence, but chose not to see it. Such was my childhood experience. As an adult, I understand that repression never heals wounds. The trauma remains as a haunting presence. But one can discover its “living presence,” should one choose to look. Just 5.2 km off the west African coast of Senegal lies Gorée Island, where millions of Africans were held captive while awaiting transport into slavery. Much of the four-century history of the African slave trade passed through Senegal, where I grew up. In this essay, I explore the history of the island and its role in the slave trade. I describe my own coming to terms with this history—how it has haunted me since my youth. And I argue for the role of visual rhetorics in the formation (and affirmation) of Senegalese ethos. As Baumlin and Meyer (2018) remind us, we need to speak, in order to be heard, in order to be seen: Such is an assumption of rhetorical ethos. And the reverse, as I shall argue, may be true, too: Sometimes we need to see (or be seen), in order to know what to speak and how to be heard. It is for this reason that we need more films written, directed, produced, and performed by Africans (Senegalese especially). Full article

In addition to traditional project management objectives (cost, time, scope and quality, among others), it is now necessary to include a global sustainability objective in all projects, regardless of their nature and scale. The processes for managing this objective may include sub-processes for optimising the sustainability of some or all of the project’s deliverables. In this paper an integrated optimisation technique was applied to optimise the design of a shell and tube heat exchanger (STHE) by taking into account economic, social and environmental indicators. A case study previously analysed in the literature, although with different objectives and scope, was considered for such a purpose. Diverse sets of weights were defined for the environmental impacts, as well as two additional cases. In the first one, all the indicators where assessed in a linear way. Non-linearities were studied in the second one. Both non-nature-inspired (exhaustive search and Monte Carlo simulation) and nature-inspired (Particle Swarm Optimisation, Crow Search Algorithm and Non-dominated Sorting Genetic Algorithm-II) optimisation techniques were used to solve the problem. The results were presented and discussed in depth. The findings show the necessity of applying these kinds of methodologies in the design of energy systems and, in particular, STHEs. Full article