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A natural gas combined cooling, heating, and power (CCHP) system is a typical integrated energy supply method that optimizes end−use energy. However, how to achieve economically feasible natural gas CCHP in severe cold regions with low−grade heat demand reaching 50% is still a pressing issue. This paper establishes a typical natural gas CCHP system model for severe cold regions and conducts the system. Based on the climate conditions of Harbin, the economic optimization of independent gas turbine systems, internal combustion engines, and gas turbine systems is still a pressing issue. Based on the climate conditions of Harbin, the economic optimization of independent gas turbine systems, internal combustion engine systems, and steam boiler systems under different cooling and heating load ratios was carried out. The combination of “internal combustion engine + steam boiler” has the most optimal cost of RMB 1.766 million (USD 0.255 million), saving 10.7%, 7.8%, and 18.3% compared to the three single equipment subsystems respectively. This provides good theoretical support for the construction of multi−energy heterogeneous energy systems.

Fear generalization is a crucial mechanism underlying maladaptive behavior, but factors influencing this process are not fully understood. We investigated the effects of cue training and context on fear generalization and how cognitive rules influence responses to different conditions. We also examined the role of stimulus intensity in fear generalization to provide insight into fear generalization mechanisms. Participants (n = 104) completed a fear emotion task with two stages: acquisition and generalization testing. Subjective fear expectancy ratings were used as outcome measures. Participants who received single threat cue training exhibited stronger fear generalization responses than those who received discrimination training with threat and safe cues. Participants who received discrimination training and used linear rules had the strongest fear response to the largest stimulus. Therefore, a safe cue may mitigate fear generalization but could increase fear responses to more intense stimuli. Altering context did not change the fear generalization response because fear generalization is mainly governed by the association between the conditioned stimulus and the unconditioned fear stimulus. The present study emphasizes the multifaceted nature of fear generalization and the importance of examining multiple factors to understand this phenomenon. These findings elucidate fear learning and provide insights needed for effective interventions for maladaptive behavior.

Background Radiotherapy plays an important role in numerous tumor clinical treatments and over 65% of cancer patients need to accept radiotherapy all over the world. However, tumor angiogenesis and metastasis induced by conventional photon radiotherapy adversely impact the survival of patients, and limit the clinical radiotherapy efficiency. Heavy-ion radiotherapy has attracted wide attention in recent years because of its excellent physical property and outstanding tumor control rate, however, the underlying gene expression regulation mechanism response to heavy-ion irradiation remains elusive. Methods RNA-sequencing (RNA-seq) and public database analysis were employed to identify the differential molecular changes in lung adenocarcinoma cells exposed to both X-ray and carbon ion (C-ion) irradiation. The expression of the identified LINC00167 was verified by real-time quantitative PCR in different lung cancer cell lines and pulmonary bronchial epithelial cell lines. The content of serum vascular endothelial growth factor (VEGF) and transforming growth factor beta 1 (TGF-β1) of 8 lung cancer patients who received X-ray or carbon ion radiotherapy were detected by ELISA experiment. Loss-of-function and gain-of-function experiments were performed to explore the biological roles of LINC00167 and miR-663a in lung cancer cell angiogenesis and metastasis. Comprehensive biochemical and biological techniques were utilized to explore the functions of LINC00167 in tumor angiogenesis and metastasis induced by different radiation types. Results In this study, we confirmed that LINC00167 was highly expressed and induced by X-ray irradiation in lung cancer cells. Moreover, increased LINC00167 expression was positively correlated with tumor angiogenesis and metastasis caused by conventional photon radiotherapy. LINC00167 worked as a sponge of miR-663a to positively regulate the expression of TGF-β1 and the downstream VEGF signaling and then promoted the tumor angiogenesis and metastasis of lung cancer cells. LINC00167 could strengthen the pro-angiogenesis and metastasis ability of lung cancer cells. Photon radiation-induced LINC00167 promoted angiogenesis both in vitro and in vivo. Conclusion Our data suggest that LINC00167/miR-663a/TGF-β1 axis is involved in the differential angiogenic response of lung adenocarcinoma cells exposed to X-ray or C-ion irradiation, providing the molecular mechanisms underlying the suppressed angiogenic response induced by carbon ion radiotherapy.

This study aimed to explore the regulatory mechanism of methyltransferase3 (METTL3) -mediated long non-coding RNA (lncRNA) N6-methyladenosine (m6A) modification in the osteogenic differentiation of human adipose-derived stem cells (hASCs) induced by NEL-like 1 protein (NELL-1). Methylated RNA immunoprecipitation sequencing (MeRIP-seq) and high- throughput sequencing for RNA (RNA-seq) were performed on hASCs. Osteogenic ability was detected by alkaline phosphatase (ALP) staining, Alizarin Red S(ARS) staining, ALP quantification and Quantitative real-time polymerase chain reaction analysis (qRT-PCR). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis predicted the osteogenesis-related pathways enriched for the lncRNAs and identified the target lncRNAs. After overexpression and knockdown of METTL3, methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) and qRT-PCR were used to detect the levels of m6A modification and the expression of the target lncRNA, and the binding of both was confirmed by RNA binding protein immunoprecipitation (RIP) assay. The effects of lncRNA and METTL3 on phosphorylation of the key proteins of the pathway were detected by western blot analysis. In vitro experiments showed that METTL3 can promote osteogenic differentiation and that its expression level is upregulated. KEGG pathway analysis predicted that lncRNAs with differentially upregulated methylated peaks were enriched mostly in the mitogen-activated protein kinase (MAPK) signaling pathway, in which Serine/threonine protein kinase 3 (STK3) was the predicted target gene of the lncRNA RP11-44 N12.5. The m6A modification and expression of RP11-44 N12.5 were both regulated by METTL3. Subsequently, lncRNA RP11-44 N12.5 and METTL3 were found to regulate the phosphorylation levels of three key proteins in the MAPK signaling pathway, ERK, JNK and p38. This study shows, for the first time, that METTL3 can activate the MAPK signaling pathway by regulating the m6A modification and expression of a lncRNA, thereby enhancing the osteogenic differentiation of hASCs.

Objectives Adipose-derived stem cells are frequently used for bone regeneration both in vitro and in vivo. N6-methyladenosine (m6A) is the most abundant post-transcriptional modification on eukaryotic RNAs and plays multifaceted roles in development and diseases. However, the regulatory mechanisms of m6A in osteogenic differentiation of human adipose-derived stem cells (hASCs) remain elusive. The present study aimed to build the transcriptome-wide m6A methylome during the osteogenic differentiation of hASCs. Materials and methods hASCs were harvested after being cultured in a basic or osteogenic medium for 7 days, and the osteogenic differentiation was validated by alkaline phosphatase (ALP) and Alizarin Red S staining, ALP activity assay, and qRT-PCR analysis of ALP, RUNX2, BGLAP, SPP1, SP7, and COL1A1 genes. The m6A level was colorimetrically measured, and the expression of m6A regulators was confirmed by qRT-PCR and western blot. Moreover, m6A MeRIP-seq and RNA-seq were performed to build the transcriptome and m6A methylome. Furthermore, bioinformatic analyses including volcano plots, Venn plots, clustering analysis, Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, gene sets enrichment analysis, and protein-protein interaction analysis were conducted. Results In total, 1145 differentially methylated peaks, 2261 differentially expressed genes, and 671 differentially methylated and expressed genes (DMEGs) were identified. GO and KEGG pathway analyses conducted for these DMEGs revealed extensive and osteogenic biological functions. The “PI3K-Akt signaling pathway”; “MAPK signaling pathway”; “parathyroid hormone synthesis, secretion, and action”; and “p53 signaling pathway” were significantly enriched, and the DMEGs in these pathways were identified as m6A-specific key genes. A protein-protein interaction network based on DMEGs was built, and VEGFA, CD44, MMP2, HGF, and SPARC were speculated as the hub DMEGs. Conclusions The total m6A level was reduced with osteogenic differentiation of hASCs. The transcriptome-wide m6A methylome built in the present study indicated quite a few signaling pathways, and hub genes were influenced by m6A modification. Future studies based on these epigenetic clues could promote understanding of the mechanisms of osteogenic differentiation of hASCs.

This study aimed to explore the regulatory mechanism of methyltransferase3 (METTL3) -mediated long non-coding RNA (lncRNA) N6-methyladenosine (mMethylated RNA immunoprecipitation sequencing (MeRIP-seq) and high- throughput sequencing for RNA (RNA-seq) were performed on hASCs. Osteogenic ability was detected by alkaline phosphatase (ALP) staining, Alizarin Red S(ARS) staining, ALP quantification and Quantitative real-time polymerase chain reaction analysis (qRT-PCR). Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis predicted the osteogenesis-related pathways enriched for the lncRNAs and identified the target lncRNAs. After overexpression and knockdown of METTL3, methylated RNA immunoprecipitation-qPCR (MeRIP-qPCR) and qRT-PCR were used to detect the levels of mIn vitro experiments showed that METTL3 can promote osteogenic differentiation and that its expression level is upregulated. KEGG pathway analysis predicted that lncRNAs with differentially upregulated methylated peaks were enriched mostly in the mitogen-activated protein kinase (MAPK) signaling pathway, in which Serine/threonine protein kinase 3 (STK3) was the predicted target gene of the lncRNA RP11-44 N12.5. The mThis study shows, for the first time, that METTL3 can activate the MAPK signaling pathway by regulating the m

Purpose Head and neck squamous cell carcinoma (HNSCC) is the sixth most prevalent cancer in the world, accounting for more than 90% of head and neck malignant tumors. However, its molecular mechanism is largely unknown. To help elucidate the potential mechanism of HNSCC tumorigenesis, we investigated the gene interaction patterns associated with tumorigenesis. Methods Weighted gene co-expression network analysis (WGCNA) can help us to predict the intrinsic relationship or correlation between gene expression. Additionally, we further explored the combination of clinical information and module construction. Results Sixteen modules were constructed, among which the key module most closely associated with clinical information was identified. By analyzing the genes in this module, we found that the latter may be related to the immune response, inflammatory response and formation of the tumor microenvironment. Sixteen hub genes were identified-ARHGAP9, SASH3, CORO1A, ITGAL, PPP1R16B, TBC1D10C, IL10RA, ITK, AKNA, PRKCB, TRAF3IP3, GIMAP4, CCR7, P2RY8, GIMAP7, and SP140. We further validated these genes at the transcriptional and translation levels. Conclusion The innovative use of a weighted network to analyze HNSCC samples provides new insights into the molecular mechanism and prognosis of HNSCC. Additionally, the hub genes we identified can be used as biomarkers and therapeutic targets of HNSCC, laying the foundation for the accurate diagnosis and treatment of HNSCC in clinical and research in the future.

To help provide evidence for prognosis prediction and personalized targeted therapy for patients with head and neck squamous cell carcinoma (HNSCC), we investigated prognosis-specific methylation-driven genes in HNSCC. Survival time data, RNA sequencing data, and methylation data for HNSCC patients were downloaded from The Cancer Genome Atlas. The MethylMix R package based on the β mixture model was utilized to screen genes with different methylation statuses in tumor tissues and adjacent normal tissues, and a total of 182 HNSCC-related methylation-driven genes were then identified. A survival prediction scoring model based on multivariate Cox analysis was developed to screen the genes related to the prognosis of HNSCC, and a linear risk model of the methylation status of six genes (INA, LINC01354, TSPYL4, MAGEB2, EPHX3, and ZNF134) was constructed. The prognostic values of the six genes were further independently explored by survival analysis combined with methylation and gene expression analyses. The 5-year survival rate in the high-risk group of patients in the test set was 30.4% (95% CI: 22.7%-40.8%) and that in the low-risk group of patients was 65.5% (95% CI: 56.1%-76.5%). The area under the receiver operating characteristic curve for the model was 0.723, which further verified the specificity and sensitivity of the model. In addition, subsequent combined survival analysis revealed that all six genes could be used as independent prognostic markers and thus might be potential drug targets. The innovative method provides new insight into the molecular mechanism and prognosis of HNSCC.

With the application and popularization of distributed power supply and power electronic equipment in power grid, AC distribution is faced with problems such as low efficiency and low power quality. At the same time, due to the advantages of large power supply capacity, long power supply radius, high efficiency, good controllability and adaptability to renewable energy access, DC power distribution has become a crucial development direction of the future distribution system. Reasonable and systematic analysis of power quality problems of DC distribution network plays an important role in its construction and application. Firstly, this paper introduces the background, significance and status of the research on DC distribution network and its power quality. Then introduces the three main topology of DC distribution network structure and connection mode. After selecting pseudo bipolar structure to build the simulation circuit, the power quality phenomena such as voltage sag are simulated and analyzed by PSCAD. The results obtained are consistent with theoretical analysis.

Through the covalent bonding between naphthalenediimide diamine (NDIDA) and graphene oxide (GO), we synthesize NDIDA-functionalized graphene oxide (NDIDA-GO). The as-synthesized NDIDA-GO is characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and the Brunauer–Emmett–Teller surface area analysis. As a cathode material for lithium-ion batteries, within a voltage window of 4.5–1.5 V, NDIDA-GO exhibits a high specific capacity, good cyclic stability, and rate capability, keeping a specific capacity of 240 mA h g−1 after 50 cycles at 50 mA g−1. This work provides an effective route for the development of high-performance organic-based cathode materials for lithium-ion batteries.

Widely used LED electronic displays have high requirements for power quality. Because of the status quo of LED technology update and the lack of related experimental work, this paper first analyzes the hardware composition of LED electronic display and switching power supply module. In addition, the paper points out that the transient tolerance of LED screens is mainly determined by switching power supply modules. Then, a test platform was built, and a certain type of LED screen was selected to investigate the influence of voltage temporary drop value and duration, phase jump, and initial Angle of temporary drop on the tolerance of LED electronic display. It provides data support for evaluating and managing the effects of voltage sags on LED electronic displays and the design of power supply schemes.

A three-dimensional (3D) copper-based coordination polymer, ([Cu(H2mpca)(tfbdc)], Cu-CP; H2mpca = 3-methyl-1H-pyrazole-4-carboxylic acid; H2tfbdc = 2,3,5,6-tetrafluoroterephthalic acid), has been synthesized and characterized by IR spectroscopy, thermogravimetric analysis, elemental analysis, and single-crystal X-ray diffraction. In Cu-CP, each Cu(II) ion is located in a triangular bipyramid geometry, and these Cu(II) ions are linked by tfbdc2– ligands to produce a 3D network. Variable-temperature magnetic susceptibility data display that weak antiferromagnetic interactions between the adjacent Cu (II) ions exist in Cu-CP. Cu-CP was evaluated as an electrode material for supercapacitors. It displayed a higher specific capacitance of 735 F g–1 in 1 M KOH solution at a current density of 1 A g–1 and remained at 375 F g–1 after 1500 cycles at 2 A g–1.

A zinc-based one-dimensional (1D) coordination polymer ([Zn(H2mpca)2(tfbdc)(H2O)], Zn-ODCP) has been synthesized and characterized by spectroscopic and physicochemical methods, single-crystal X-ray diffraction, and thermogravimetric analysis (H2mpca = 3-methyl-1H-pyrazole-4-carboxylic acid; H2tfbdc = 2,3,5,6-tetrafluoroterephthalic acid). Zn-ODCP shows blue luminescence in the solid state. When Zn-ODCP acts as an anode material for lithium ion batteries, it exhibits a good cyclic stability and a higher reversible capacity of 300 mAh g–1 at 50 mA g–1 after 50 cycles. The higher capacity may be mainly ascribed to the metal ion and ligand all taking part in lithium storage. Searching for electrode materials of lithium ion batteries from 1D metal coordination polymers is a new route.

This numerical study investigates turbulent flow characteristics and heat transfer augmentation in a rectangular channel with elliptical cylinders and protrusions. The height of protrusions...

Nickel-based metal-organic framework ([Ni(4,4′-bpy)(tfbdc)(H2O)2], Ni-MOF) nanoparticles with the size of 45–250 nm were synthesized by a facile hydrothermal route in combination with a grinding treatment (4,4′-bpy = 4,4′-bipyridine, H2tfbdc = tetrafluoroterephthalic acid). The materials were characterized by elemental analysis, IR spectrum, thermogravimetric analysis, powder X-ray diffraction, X-ray photoelectron spectrum (XPS), transmission electron microscope (TEM), scanning electron microscope (SEM), and the Brunauer–Emmett–Teller (BET) surface. As electrode materials for supercapacitors, the Ni-MOF nanoparticles delivered a high specific capacitance of 2548 F g−1 in 1 M KOH solution at a current density of 1 A g−1. When applied as anode materials of Li-ion batteries, the Ni-MOF nanoparticles displayed a higher reversible capacity, a better cyclic stability, and a higher rate performance, which still maintained 406 mAh g−1 after 50 cycles at a current density of 50 mA g−1. The better electrochemical performances may be attributed to the unique structure feature, and short route for electrolyte/Li-ions diffusion in nanosized Ni-MOF.

For the development of supercapacitors with higher energy densities, metal–organic frameworks (MOFs), as electrode materials for supercapacitors, have attracted much attention. Herein, layered manganese-based MOF ([Mn(tfbdc)(4,4′-bpy)(H2O)2], Mn-LMOF; H2tfbdc = 2,3,5,6-tetrafluoroterephthalic acid, 4,4′-bpy = 4,4′-bipyridine) was synthesized by a simple solution reaction and evaluated as an electrode material for supercapacitors for the first time. The Mn-LMOF electrode showed a high specific capacitance, a good cycling stability and a improved rate capability. Its maximum specific capacitances were 1098 F g−1 for 1 M KOH and 1178 F g−1 for 1 M LiOH solutions at a current density of 1 A g−1. The specific capacitance retention was maintained at 92.6% after 2000 cycles in 1 M KOH, slightly lower than that in 1 M LiOH. The excellent supercapacitive performance may be ascribed to the nature of Mn-LMOF, containing a layered structure and nano-sized particles.

The flow over four square cylinders in an in-line, square arrangement was numerically investigated by using the finite volume method with CFD techniques. The working fluid is an incompressible ideal gas. The length of the sides of the array, L, is equal. The analysis is carried out for a Reynolds number of 300, with center-to-center distance ratios, L/D, ranging from 1.5 to 8.0. To fully understand the flow mechanism, details in terms of lift and drag coefficients and Strouhal numbers of the unsteady wake frequencies are analyzed, and the vortex shedding patterns around the four square cylinders are described. It is concluded that L/D has important effects on the drag and lift coefficients, vortex shedding frequencies, and flow field characteristics.

To keep the spatially averaged temperature and thermal stress of gas turbine blades and guide vanes within a permissible level, the present research concentrates on the optimization of the internal cooling passages in a guide vane. The main purpose is to search for the most optimal sizes, distributions, and shapes of internal cooling channels located in a guide vane. Cylindrical cooling passages and newly built passages shaped by Bezier curves are both considered in this investigation. In order to maintain the shapes of the cooling channels within the scale of the vane profile, a new technique is suggested to discretize the vane into the components, and then the outline of the passages is built based on the components. The optimization of sizes, locations, and shapes of the cooling passages is solved as a single-objective problem using a gradient-based optimization algorithm, i.e., the globally convergent method of moving asymptotes (GCMMA). The optimized result displays a substantial reduction in...

The flow over two different shaped bluff bodies in tandem arrangement was numerically investigated by using the finite volume method with Computational Fluid Dynamics (CFD) techniques. The shape of the downstream main bluff body is a right circular cylinder, with shape unchanged, while the shape of the upstream bluff body varies between: circle, triangle, square, ellipse and cylindrical half-shell. The hydraulic diameters of both front and rear bluff bodies are equal. The analysis is carried out for Reynolds numbers of 100, 300 and 500, and center-to-center distance ratios, L/D, of 1.5, 2, 3, 4.5 and 6. Flow characteristics in terms of the lift and drag coefficients and Strouhal number are analyzed and the vortex shedding patterns around the bluff bodies are described. The influence of the shape of the fore cylinder on the flow characteristics is the innovation point of this paper. It is concluded that the center-to-center distance ratio, L/D, and the shape of the upstream bluff body have important effects on the drag and lift coefficients, vortex shedding frequencies from the two bluff bodies, and flowfield characteristics.

In this study, five models, including the standard k-epsilon (SKE), realizable k-epsilon (RKE), SST k-omega, transition k-kl-omega, and the v(2)f model, are considered to simulate air flow and heat transfer of a turbine guide vane. The object in this paper is the well-studied NASA C3X turbine vane, for which experimental data are available. Ten internal cylindrical cooling channels are used to cool the blade. Three-dimensional temperature distributions of the turbine vane were obtained by a fluid-solid conjugated model including the external aerodynamic flow, internal convection and heat conduction region within the metal vane. In order to validate the computational results, the temperature distributions, static pressure distributions, and heat transfer coefficient distributions along the vane external mid-span surface are compared with experimental data. The 4-5-2-1 arrangement of the C3X cascade is selected, and the fluid is assumed to be an ideal gas. The results reveal that the SST k-omega turbulence model performs quite well in predicting the conjugate heat transfer. Detailed heat transfer distributions in the main passage are also shown. The representative transitional behavior of the C3X vane on both pressure and suction surfaces is further analyzed. It suggests that the transition behavior plays a significant role in predictions of the boundary-layer behavior, wall temperature distribution, and heat transfer performance. (Less)

In this paper a new generation of wavy-fin channels of a compact heat exchanger is investigated based on the Constructal Theory with maximizing the heat transfer rate and minimizing the pressure losses. Three dimensionless variables such as the channel space, the wavelength ratio and the amplitude ratio of two wavy walls are considered to find the optimal configuration of wavy-fin channels for the compact heat exchanger applied in a heat recovery system of a microturbine. Two dimensional numerical simulations are conducted to obtain the steady laminar heat transfer and pressure drop characteristics by using Computational Fluid Dynamics (CFD). All of the CFD simulations are carried out for a sufficiently long time so that the initial conditions are completely convected out of the channels and have no effects on simulated results. The results show that the new generation of wavy-fin channel can help to reduce the pressure drop by more than 54% and to enhance the heat transfer rate by around 26%. The optimal design regions of the three dimensionless parameters are also provided so as to help design wavy-fin heat exchangers.

Flow characteristics and heat transfer performances of rectangular dimpled channels with secondary protrusions are numerically analyzed and compared in this research work. The special arrangement is a conventional dimpled cavity with a small-size secondary protrusion placed upstream of the dimple. The objective is to determine the most optimal configuration for augmenting heat transfer rates with minimized pressure drop penalties, and providing flow details of secondary protrusions with different arrangements or geometries. The main considered parameters are the height ratios and relative location of the secondary protrusions placed upstream of the dimple. All turbulent fluid flows and surface heat transfer results are obtained using computation fluid dynamics with a validated k-epsilon RNG (Re-Normalization Group) turbulence model in eight rectangular channels with different secondary protrusion arrangements. From this investigation, it is found that secondary protrusions cause downward flows and reduce the extent of the recirculating flows in the adjacent primary dimple and then greatly improve the averaged local heat transfer of the corresponding primary dimple surface. In addition, secondary protrusions can improve the reattachment and strengthen the shedded vortex structures from the dimple. The heat transfer is enhanced with increasing height of the secondary protrusions but the pressure drop is also increased significantly. The largest Nu/Nu(0)/(f/f(0)) factor is obtained by a depth ratio of 0.1 and the largest Nu/Nu(0)/(f/f(0))(1/3) factor is provided by a depth ratio of 0.2. The vortex structure formed downstream of the secondary protrusions remains to take effect and develop in the primary dimple if the secondary protrusions are located near the centerline area as in Case Cl. The acting vortex structures can improve the spanwise flow and improve the turbulent mixing downstream of the dimple. With a secondary protrusion located away from the centerline, the heat transfer enhancement is weakened. The heat transfer augmentation and overall thermal performance advantages of a dimpled channel with secondary protrusions are evident compared with conventional dimpled channels. (C) 2014 Elsevier Ltd. All rights reserved. (Less)

This paper presents an optimization of shell and tube heat exchangers with respect to the total annual costs by a cuckoo search algorithm. The total annual cost is considered as the optimization objective so as to obtain economic heat exchanger structures. The performance of the CSA algorithm is further compared with various algorithm representative of the state of the art in heat exchanger optimization. The optimal results obtained by the CSA algorithm are much better than the best solutions obtained by the existed methods. Two case studies show the operating costs can be reduced by 77% and 48% compared to the results obtained from PSO (Particle Swarm Optimization) and GA (Genetic Algorithm), respectively.

Layered zinc-based metal-organic framework ([Zn(4,4′-bpy)(tfbdc)(H2O)2], Zn-LMOF) nanosheets were synthesized by a facile hydrothermal method (4,4′-bpy = 4,4′-bipyridine, H2tfbdc = tetrafluoroterephthalic acid). The materials were characterized by IR spectrum, elemental analysis, thermogravimetric analysis, powder X-ray diffraction, transmission electron microscope (TEM), scanning electron microscope (SEM), and the Brunauer–Emmett–Teller (BET) surface. When the Zn-LMOF nanosheets with the thickness of about 24 ± 8 nm were used as an anode material of lithium-ion batteries, not only the Zn-LMOF electrode shows a high reversible capacity, retaining 623 mAh g−1 after 100 cycles at a current density of 50 mA g−1 but also exhibits an excellent cyclic stability and a higher rate performance.

Enhancement of bottom wall forced convection heat transfer rates in a ribbed cooling channel combined with differently shaped deflectors is investigated numerically. Four deflectors, including the sloping board (Case A), convex curved (Case B), concave curved (Case C), and cylindrical (Case D) deflectors, are mounted on the upper-downstream side of the ribs. The heat transfer and flow features are analyzed and compared based on the validation of the turbulence model and careful study of the grid independence. The results show that the flow structures are deeply affected by the deflectors, accompanied by changes in the heat transfer and friction factor. Compared with the ribbed channel with sloping board deflectors, Case B can guide the mainstream fluid to compress the recirculating flow region located on the lee-side regions downstream from the rib and can enhance the heat transfer of the bottom surface, despite the increasing friction factor. It is noted that the decrement ratio of the friction factor in Case D is 7.0-12.4%. Based on this remarkable expression, Cases B and D contribute to better overall performance. This is due to their prominent performance in the heat transfer enhancement and diminished flow resistance. (Less)

Author(s): Johnson, Keith; Song, Yidan | Abstract: Sounds that are contrastive in a language are rated by listeners as being more differentfrom each other than sounds that don’t occur in the language or sounds that areallophones of a single phoneme. The study reported in this paper replicates this findingand adds new data on the perceptual impact of learning a language with a new contrast.Two groups of speakers of the Nanjing dialect of Mandarin Chinese were tested. Onegroup was older and had not been required to learn standard Mandarin as school children,while the other younger group had learned standard Mandarin in school. Nanjing dialectdoes not contrast [n] and [l], while standard Mandarin does. Listeners rated the similarityof naturally produced non-words presented in pairs, where the only difference betweenthe tokens was the medial consonant. Pairs contrasting [n] and [l] were rated by olderNanjing speakers as if two [n] tokens or two [l] tokens had been presented, while thesesame pairs were rated by younger Nanjing speakers as noticeably different but not asdifferent as pairs that contrast in their native language.

Pin-fins are considered as one of the best elements for heat transfer enhancement in heat exchangers. In this study, the topology of pin-fins (length, diameter, and shape) is optimized based on the entropy generation minimization (EGM) theory coupled with the constructal law (CL). Such pin-fins are employed in a heat exchanger in a sensible thermal energy storage (TES) system so as to enhance the rate of heat transfer. First, the EGM method is used to obtain the optimal length of pin-fins, and then the CL is applied to get the optimal diameter and shape of pin-fins. Reliable computational fluid dynamics (CFD) simulations of various constructal pin-fin models are performed, and detailed flow and heat transfer characteristics are presented. The results show that by using the proposed system with optimized pin-fin heat exchanger the stored thermal energy can be increased by 10.2%.