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Reforming ammonia to hydrogen using engine exhaust waste heat is a promising technology to improve the combustion performance and reduce the exhaust emissions of ammonia-fueled engines. However, there are still a research gap between the laboratory-level catalytic reforming tests and the practical application in engine systems. In particular, there are urgent needs to further understanding the ammonia reforming characteristics and developing the simulaiton models for the engine system optimization. In this paper, we conducted the experiments of catalytic reforming NH 3 to H 2 to study the effects of the reaction temperature, gas hour space velocity (GHSV) and pressure on the thermo-catalytic decomposition characteristicsxin. The results indicate that both the ammonia catalytic conversion and reforming efficiency exhibit an increasing trend with the rise in reaction temperature, while these two parameters demonstrate a decreasing trend with the increase in GHSV and pressure. The rate of hydrogen production is directly proportional to temperature, GHSV, and reaction pressure. Conversely, the energy required per unit of hydrogen production decreases with temperature but increases with GHSV and reaction pressure. The energy flow analysis shows that increasing the reforming temperature increases the reforming losses, but the total calorific value of the reformate increases, which is expected to improve the overall efficiency of ammonia fueled engines and reduce the unburned ammonia emissions. Simulation results show that, the improved Temkin-Pyzhev global rate model can significantly improve the accuracy of the ammonia catalytic decomposition process prediction. [Display omitted] • A novel energy flow analysis method for thermo-catalytic reforming is presented. • A precise predictive model for thermo-catalytic characteristics is established. • The thermo-catalytic system has a system efficiency of up to 94%. • The thermo-catalytic system has a reforming efficiency of up to 112%. [ABSTRACT FROM AUTHOR]

Ammonia (NH 3), hydrogen (H 2) and methane (CH 4) as zero- or low-carbon fuels are considered as highly promising alternative fuels. Turbulent non-premixed jet combustion is a prospective way in practical combustion devices for ammonia, hydrogen and methane, but the relevant experimental researches are rare, while such information is critical for the development and validation of numerical models. In this paper, the laser diagnostic studies are carried out in a constant volume combustion chamber to investigate the characteristics of the 50%NH 3 +50%H 2 blend jet with or without ignition in comparison to H 2 , CH 4 and NH 3 jets. Firstly, the morphological developments and concentration distributions of the four gas jets without ignition are compared. Then, the OH or NO distributions in the non-premixed gas jet flames are clarified by the planar laser-induced fluorescence techniques. The generation and consumption processes of OH and NO are elucidated by the one-dimensional simulation. The results show that the four jets exhibit a similar morphological development with the nearly same jet angles, except for a little slower tip penetration of 50%NH 3 +50%H 2 blend. The equivalence ratio of the 50%NH 3 +50%H 2 blend and NH 3 jets along the jet axis are lower than those in the CH 4 and H 2 jets due to the difference in the flow rate and stoichiometric number. The H 2 jet exhibits the highest combustion intensity, featuring faster flame propagation, the shortest lift-off length and an apparently higher OH radical intensity, while the NH 3 jet fails to develop a stable flame. The mixture in the 50%NH 3 +50%H 2 blend jet is too lean, resulting in a weaker combustion intensity than the H 2 and CH 4 jets. However, the NO intensity in the 50%NH 3 +50%H 2 jet flame is remarkably stronger than those of the H 2 and CH 4 jet, due to the much higher amount of fuel-type NO converted from NH 3 than that of thermal NO. A self-reducing (SR) zone can be observed where OH is produced and then consumed in the 50%NH 3 +50%H 2 blend, H 2 and CH 4 jet flames. However, the NO SR zone is only observable in the 50%NH 3 +50%H 2 blend jet flames, probably owing to the consumption by the NH 2 and NH radicals. • The laser diagnostic was used to obtained the OH and NO distributions. • The 50%NH 3 +50%H 2 , H 2 , CH 4 and NH 3 jets exhibit a similar morphologic development. • The equivalence ratios of the 50%NH 3 +50%H 2 blend and NH 3 jets are the lowest. • The fuel-type NO makes the strongest NO intensity in 50%NH 3 +50%H 2 blend flames. • For the first time a self-reducing zone was observed for the OH and NO. [ABSTRACT FROM AUTHOR]

Background: Hyperselective neurectomy is a reliable treatment for spasticity. This research was designed to quantify the surgical parameters of hyperselective neurectomy of thoracodorsal nerve for shoulder spasticity through anatomical studies, as well as to retrospectively assess patients who underwent this procedure to provide an objective basis for clinical practice. Methods: On nine embalmed adult cadavers (18 shoulders), we dissected and observed the branching patterns of thoracodorsal nerve, counted the number of nerve branches, measured the distribution of branch origin point, and determined the length of the surgical incision. Next, we selected five patients who underwent this procedure for shoulder spasticity and retrospectively evaluated (ethic committee: 2022–37) their shoulder function with active/passive range of motion (AROM/PROM) and modified Ashworth scale (MAS). Results: The anatomical study revealed that the main trunk of thoracodorsal nerve sends out one to three medial branches, with the pattern of only one medial branch being the most common (61.1%); there were significant variations in the branch numbers and nerve distributions; the location of thoracodorsal nerve branches' entry points into the muscle varied from 27.2 to 67.8% of the length of the arm. Clinical follow-up data showed significant improvement in shoulder mobility in all patients. AROM of shoulder abduction increased by 39.4° and PROM increased by 64.2° (P < 0.05). AROM and PROM of shoulder flexion increased by 36.6° and 54.4°, respectively (P < 0.05). In addition, the MAS of shoulder abduction (1.8) and flexion (1.2) was both significantly reduced in all patients (P < 0.05). Conclusion: Hyperselective neurectomy of thoracodorsal nerve is effective and stable in the treatment of shoulder spasticity. Intraoperative attention is required to the numbers of the medial branch of thoracodorsal nerve. We recommend an incision in the mid-axillary line that extends from 25 to 70% of the arm length to fully expose each branch. [ABSTRACT FROM AUTHOR]

Individuals with gambling disorder display deficits in decision-making in the Iowa Gambling Task. The rat Gambling Task (rGT) is a rodent analogue that can be used to investigate the neurobiological mechanisms underlying gambling behaviour. The aim of this explorative study was to examine individual strategies in the rGT and investigate possible behavioural and neural correlates associated with gambling strategies. Thirty-two adult male Lister hooded rats underwent behavioural testing in the multivariate concentric square field™ (MCSF) and the novel cage tests, were trained on and performed the rGT and subsequently underwent resting-state functional magnetic resonance imaging (R-fMRI). In the rGT, stable gambling strategies were found with subgroups of rats that preferred the suboptimal safest choice as well as the disadvantageous choice, that is, the riskiest gambling strategy. R-fMRI results revealed associations between gambling strategies and brain regions central for reward networks. Moreover, rats with risky gambling strategies differed from those with strategic and intermediate strategies in brain functional connectivity. No differences in behavioural profiles, as assessed with the MCSF and novel cage tests, were observed between the gambling strategy groups. In conclusion, stable individual differences in gambling strategies were found. Intrinsic functional connectivity using R-fMRI provides novel evidence to support the notion that individual differences in gambling strategies are associated with functional connectivity in brain regions important for reward networks. [ABSTRACT FROM AUTHOR]

Silicon carbide (SiC) is a wide-bandgap (WBG) semiconductor material, and its preparation process has strict requirements on the purity of raw materials. A self-developed medium-frequency induction heating furnace was used to carry out powder heat treatment and purification experiments on SiC powder to improve the purity of the powder. Samples with 3.5N purity were analyzed using XRD and GDMS characterization methods. It was found that under conditions of high-temperature (2200 °C) and long-time (50 h) processing, the impurity removal effect was quite good, but the powder loss was as high as 53.42%. The powder loss during the low-temperature (less than 2050 °C) and short-time process was less than 1.5%, but the purification effect was not substantial. After a prolonged processing time, the purification effect of low-temperature heat treatment conditions was improved, but the powder loss was also increased to 30%. In contrast, segmented purification processing at a low temperature in the early stage and a high temperature in the later stage achieved a good purification effect. On the premise of maintaining the utilization rate of raw materials, a 5N-purity SiC source was successfully prepared. The test results show that the contents of free Si, free C and free oxygen impurities were reduced to less than 0.01%, and the contents of Al, B, Fe, Mg, Na, Ti and other impurities were less than 1.15 ppm, which is close to the ppb level. [ABSTRACT FROM AUTHOR]

Low contrast, poor color saturation, and turbidity are common phenomena of underwater sensing scene images obtained in highly turbid oceans. To address these problems, we propose an underwater image enhancement method by combining Retinex and transmittance optimized multi-scale fusion framework. Firstly, the grayscale of R, G, and B channels are quantized to enhance the image contrast. Secondly, we utilize the Retinex color constancy to eliminate the negative effects of scene illumination and color distortion. Next, a dual transmittance underwater imaging model is built to estimate the background light, backscattering, and direct component transmittance, resulting in defogged images through an inverse solution. Finally, the three input images and corresponding weight maps are fused in a multi-scale framework to achieve high-quality, sharpened results. According to the experimental results and image quality evaluation index, the method combined multiple advantageous algorithms and improved the visual effect of images efficiently. [ABSTRACT FROM AUTHOR]

Particle volatility, size distribution, and parent and alkylated polycyclic aromatic hydrocarbon (PAH/alkyl-PAH) profiles during toluene pyrolysis in a flow reactor were studied. The experiments were conducted under three different gas residence times (0.2, 0.5 and 0.8 s) at temperatures from 950 to 1450 °C. Results showed that long residence times and high temperatures led to high particle mass concentrations, low particle volatility and a significant shift of particle size distribution to larger size. Total particle number concentrations exhibited a rise-then-fall trend (peaking at a critical temperature of 1050 °C) with increasing temperature, indicating that increasing temperature promoted a transition from nucleation to agglomeration and coagulation which dominated the particle size distributions. Among PAHs and alkyl-PAHs, those with 2–4 rings, presented the highest concentrations at 950 °C for 0.2 s. They appeared at 1050 °C for 0.5 and 0.8 s, consistent with the critical temperature of particle nucleation at long residence times (0.5 and 0.8 s). Particle peak number concentrations and total PAH mass concentrations exhibited consistent temperature dependence, indicating soot nucleation was highly related to PAH concentrations. According to the comprehensive observations in this study, low molecular mass PAHs instead of larger PAHs appear to be the precursors of soot formation during high temperature pyrolysis processes. [ABSTRACT FROM AUTHOR]

Purpose/Significance: In the past many years, some scholars have studied bid evaluation experts, such as the behavior of bid evaluation experts. However, previous research ignores the performance and competency of bid evaluation experts, so this paper aims to provide a theoretical basis for incentive and constraint mechanism and hierarchical or dynamic management of bid evaluation experts by implementing performance and dynamic competency evaluation of bid evaluation experts. Method/Process: Firstly, the evaluation index system of performance and dynamic competency of bid evaluation experts is preliminarily constructed by referring to relevant literature, and then the constructed evaluation index was modified and improved by consulting relevant stakeholders' experts. Secondly, considering the hesitation and consistency of expert weighting, the calculation method of expert weight coefficient and index score interval number is improved. Based on the theory of weight interval number, the corresponding mathematical optimization model is constructed to calculate the index weight according to the purpose of performance judgment and dynamic competency clustering of bid evaluation experts. Finally, the data of performance and dynamic competency of bid evaluation experts is obtained by questionnaire survey, and the empirical analysis was carried out by simulating the bid evaluation experts consistent with the actual situation. Results/Conclusion: After improving the calculation method of index score interval number, and then calculating index weight interval number through index score interval number, the length of index weight interval number can be decreased and the calculation accuracy of index weight interval number can be increased. In addition, the index weight calculated by the constructed mathematical optimization model can make the intra-class discrimination smaller and the inter-class discrimination larger. Finally, some suggestions are also provided for the management of bid evaluation experts. [ABSTRACT FROM AUTHOR]

Active pre-chamber turbulent jet ignition is one of the most promising technologies for developing low- or zero-carbon engines. However, the relevant fundamental studies are far from adequate, particularly for the independent impact of the pre-chamber design parameters on the jet characteristics in the absence of combustion in the main chamber. In this study, the hot turbulent jet characteristics of the pre-chamber fueled with the premixed CH 4 -air are studied by the double-pass Schlieren imaging. The effects of the pre-chamber nozzle design parameters, including the orifice diameter, total orifice cross-sectional area, and orientation are clarified. The results reveal that the pressure difference between the pre-chamber and main chamber depends on the total orifice cross-sectional area. The effects of the orifice diameter and total orifice cross-sectional area on the penetration rate exhibit a trade-off relation, while the orifice diameter has a more pronounced effect on the hot jet projection area than the total orifice cross-sectional area. Compared to the inclined orifice, the penetration velocity of the straight orifice is faster at the initial hot jet ejection stage. These results are expected to be valuable references for the pre-chamber design and understanding of the ignition mechanisms of active pre-chamber. • The temporal and spatial developments of the pre-chamber jet are presented. • The separate effects of the pre-chamber nozzle design parameters are clarified. • The straight orifice hinders the formation of pressure difference. [ABSTRACT FROM AUTHOR]

• Unburned NH 3 increased with AER raising but decrease with increased engine load and speed. • NO + NO 2 shows a non-linearity trend with increasing ammonia and a trade-off correlation to N 2 O. • N 2 O presents a parabolic-like tendency with AERs instead of a linearity trend. • The N 2 O's effect causes that more 20% ammonia is needed to achieve the same decarbonization target. In the transportation sector, ammonia used as a power source plays a significant role in the scenario of carbon neutralization. However, the engine-out emissions correlations of ammonia-diesel dual-fuel (DF) engines are still not totally clear, especially the nitro-compounds of great concern and GHG. In this study, the engine-out emissions are evaluated by using a four-cylinder pilot diesel-ignited ammonia DF engine. Various operating conditions consisting of ammonia energy ratio (AER), engine load, and speed were carried out. Unburned NH 3 increases with raising ammonia content but decreases with increasing engine load and speed. The NO + NO 2 tendency shows a non-linearity trend with increasing ammonia content, while a trade-off correlation is linked to N 2 O. The 20 % and 70 % decarbonization targets need 40 % and 80 % ammonia energy without regard to N 2 O's effect, while at least 60 % and 90 % ammonia energy respectively with considering N 2 O. N 2 O presents a parabolic-like tendency with AERs. Advanced pilot-diesel injection timing helps to reduce both NH 3 and N 2 O, but this effect becomes insignificant as the AER is less than 0.4. A combustion optimization strategy of the rapid heat release and ammonia-governed heat release respectively are revealed. The possible emission improvements are discussed in detail. [ABSTRACT FROM AUTHOR]

The presence of decentralized production in modern electrical systems precludes traditional automatic generation control (AGC) strategies. Renewable energy production is highly dependent on the environment; for example, photovoltaic (PV) system, but its power generation is very unstable, which makes power grids containing PV systems face greater challenges. In this paper, we propose a PV-grid control method based on self-gain system compensation to reduce the negative effects of large fluctuations and uncertainties in solar energy production. First, the performance characteristics of solar modules are discussed and a multi-region model with a system with high penetration of solar systems is built. The AGC power is then displayed with different power variations according to different maximum power point tracking methods to analyze the uncertainty and variation of the PV output power and its effects on the AGC. We have also developed and implemented a compensation unit to eliminate the negative effects of PV power on AGC. Finally, the proposed method was demonstrated using the load from the example step as a disturbance variable to obtain a dynamic model of a dual-zone switched grid AGC with two PV systems based on a DMPC-distributed model. As a result of the simulation, the proposed method in this paper can guarantee the excellent properties of the dynamic behavior of the AGC system with large variations and high uncertainty of the PV system, and the validity of the proposed method have also been confirmed. [ABSTRACT FROM AUTHOR]

The axial thermal errors of CNC lathes are mostly caused by the thermal deformation of the screw and spindle. It is necessary to establish a prediction model to evaluate the thermal error distribution of CNC lathes. First, a new real-time virtual frictional heat model under the time-varying working speed of various kinematic pairs in the screw and spindle systems was proposed using the real-time torque current. Furthermore, a novel one-dimension lumped capacity method, which can be used to determine the temperature field rapidly, was proposed, considering the sensitiveness of the temperature of the measuring point with the heat generation rate. By an inverse FEM thermal-solid method of screw and spindle systems, the friction heat distribution and sensitiveness of the temperature of the measuring point with the heat generation rate were obtained. Consequently, based on the one-dimension lumped capacity method, the real-time thermal error prediction model was established, which is used to predict the temperatures and axial thermal errors of the screw and spindle of the machine tools. From the FANUC digit control system, the servomotor torque currents of the screw and spindle and the position of the moving-nut were read and used as inputs by the FOCAS library function. The effectiveness of the proposed prediction model of thermal errors is verified through the experimental and FEM results. This method uses the servomotor torque current collected by the FOCAS library function to determine the heat boundary condition. It can quickly and accurately determine the thermal errors without requiring additional temperature sensors. [ABSTRACT FROM AUTHOR]

Determining the parameters of boreholes drilled for relieving pressure in coal seams is the key preventing and controlling rock bursts in boreholes of large diameter. In this study, theoretical analysis, numerical simulation, literature research, and other analysis methods are applied to study the angles of elastic energy dissipation and stress transfer, the distribution law of the pressure relief area, and the areas of stress concentration, energy, stress, displacement, and plastic behavior of large-diameter pressure relief boreholes in coal seams under high-stress conditions. The results are then used to evaluate the relationship between large-diameter pressure relief boreholes and the borehole arrangement. The following results are obtained. (1) A large-diameter results in a large amount of elastic energy released by the surrounding coal, low residual elastic energy density, strong interaction between boreholes, large pressure relief range of the borehole, and high pressure relief efficiency. (2) The main evaluation factor of the borehole pressure relief effect is its thickness and stress concentration area; secondary evaluation is based on the areas of energy, displacement, stress, and plastic behavior. (3) Six evaluation index systems are established to evaluate the effects of borehole pressure relief, which are found to be the thicknesses of the borehole pressure relief area and stress concentration area, reduction degree of energy density, percentage of stress reduction, displacement, and penetration degree of the plastic area. (4) It is determined that when the diameters of the pressure relief boreholes are 100, 120, 180, and 200 mm, a single-row borehole arrangement is adopted; a three-pattern borehole arrangement is adopted with diameters of 140 and 160 mm. These research results can provide theoretical support in selecting reasonable borehole arrangements for pressure relief boreholes of different diameters. [ABSTRACT FROM AUTHOR]

Thermal errors affect the accuracy of computer numerical control machine tools and are produced by the thermal deformation of machine components due to temperature difference between heat source and ambient temperature of the machine tools. At present, most of the literature does not consider the randomness of the influencing factors of thermal error, leading to inaccurate predictions of machine tool thermal error. In this paper, a new inverse random model is proposed through the combination of the stochastic theory, genetic algorithm, and radial basis function neural network (RBFNN), to predict thermal error while considering the randomness of influencing factors. The randomness index of influencing factors can be identified using the inverse random RBFNN (IR-RBFNN). Furthermore, through the combination of the stochastic theory, RBFNN, and the improved exponential moving average method with abnormal data elimination, a new forward random radial basis function neural network (FR-RBFNN) is established according to the identified influencing factor random index. The models are verified through experimental results on a ball screw system. Compared with the traditional methods, the experimental data show that the proposed method provides a more accurate description of thermal errors while incorporating the randomness of factors affecting thermal error. [ABSTRACT FROM AUTHOR]

Mollisols are extremely important soil resource for crop and forage production. In northeast China, it is a major land use management practice from dry land crops to irrigated rice. However, there is few data regarding soil quality and microbial composition in Mollisols during land use transition. Here, we analyzed the upper 30 cm of soil from land with more than 30 years of paddy use and from adjacent areas with upland crops. Our results showed that land use and soil depth had a significant effect on soil properties and enzyme activities. Soil moisture (SM) and soil organic carbon (SOC) contents were substantially higher in paddy fields than in upland crop lands, while nitrogen-related enzyme activities were lower. Following the land use change, bacterial diversity was increased and bacterial community composition changed. Taxonomic analyses showed that Proteobacteria, Chloroflexi, Firmicutes, and Bacteroidetes were the dominant phyla present. At family level, Gemmatimonadaceae decreased with land use change, while Syntrophorhabdaceae and Syntrophacea that play a part in methane cycling and nitrifying bacteria such as Nitrospiraceae increased, indicating that the structure and composition of the bacterial community might be a promising indicator of Mollisol health. Redundancy analysis indicated that land use type had a stronger effect on the soil bacterial community composition than soil depth. Additionally, bacterial community composition was closely associated with soil parameters such as soil moisture, pH, SOC, NO3−-N, and NH4+-N. Overall, land use change affects the physical and chemical properties of the soil, resulting in changes in the composition of the soil bacterial community and flora. These changes could provide a view of the bacterial community assembly and functional shifts following land use change. [ABSTRACT FROM AUTHOR]

Ammonia-diesel dual-fuel engines have been demonstrated as a promising technology to reduce the greenhouse gas (GHG) emissions. However, understandings of the operational boundaries and combustion mechanism in the ammonia-diesel dual-fuel engines are far from adequate, and the published works are mostly done with relatively low ammonia substitution ratios. To bridge the gap between the technology status and the potential in engineering applications, a series of engine bench tests of the pilot diesel-ignited ammonia combustion with detailed analysis of the combustion performance and exhaust gas emissions are conducted in this study to explore the GHG reduction potential. As the first report, the effects of the diesel injection timing and ammonia energetic ratio on the performance and exhaust gas emissions of the dual-fuel engine at various loads and a fixed speed are evaluated in this paper. As the ammonia energetic ratio increases, the diesel injection timing for the stable engine operation becomes narrower. Increasing the ammonia energetic ratio decreases the indicated thermal efficiency. The ammonia-diesel dual-fuel engine can maintain the stable of COV IMEP below 3% at a wide ammonia energetic ratio range, the indicated thermal efficiency with the tested upmost 90% ammonia energetic ratio can reach about 34% if an optimized diesel injection timing is implemented. The unburned ammonia increases linearly with the ammonia energetic ratio while the unburned ammonia ratios of total input ammonia are similar at the different ammonia energetic ratios. In comparison to the conventional pure-diesel mode, while the CO 2 emission decreases by 50% and 72%, the equivalent CO 2 emission (i.e., CO 2 + 265 N 2 O, labelled as CO 2e) decreases by 24% and 55% at the 60% and 80% ammonia energetic ratios in the ammonia-diesel mode, respectively. In the ammonia-diesel dual-fuel mode, the specific CO 2e , N 2 O and unburned ammonia decrease with the engine load increasing from 50% to 100%, while the highest indicated thermal efficiency is reached at the 75% load. • The effects of different diesel injection timings and ammonia energetic ratios (AERs) at various loads are investigated. • The dual-fuel engine for 90% AER can maintain the stable of COV IMEP below 3%. • The indicated thermal efficiency for 90% AER can be about 34% if the proper diesel injection timing is chosen. • The equivalent CO 2 emission (CO 2e , CO 2 + 265 N 2 O) decreases by 24% and 55% for 60% and 80% AERs, respectively. • The better effect of CO 2e reduction can be achieved at the higher load in the dual-fuel mode. [ABSTRACT FROM AUTHOR]

• Energy density and load response are considered in optimization simultaneously. • Multiple indexes are integrated into an evaluation result. • Normalized optimization variables extend the applicability of the proposed method. • The method demonstrates high effectiveness in improving economics and reliability. System component sizes and their energy densities impact the long-term ship energy efficiency and economics, whereas power source load response influences system transient behavior, posing challenges to system design and energy management when clean fuels are used onboard. In this paper, a novel component sizing method is proposed for integrating reciprocating gas engines and energy storage systems (ESS) on ships, considering energy density and load response simultaneously. By specifying gas engine powers and ESS capacities as normalized optimization variables by ship scales, this method optimizes them based on the A. J. Klee multi-index evaluation and single-objective particle swarm optimization (PSO). Energy densities of engines and ESS were introduced to demonstrate the trade-off between the power-splitting and increased system mass and hull resistance. The engine load response was incorporated into the rule-based energy management strategy (EMS) to limit power ramps. This method was examined in the case study by taking four cruise ships as examples. It can be found that implementing the proposed evaluation-based optimization can improve cruise ship energy efficiency while maintaining reliability over the voyage. It is possible to reduce fuel consumption and carbon emissions by up to 17.1% and 14.8%, respectively. The minimum system reliability can be increased from 0.025 to 0.475 during transients. Furthermore, ship life-cycle costs can be reduced compared to the original design method, and the payback period for gas engines, ESS, and fuel tanks can be shortened to less than six years. Among the various cases, the definition of normalized optimization variables broadens the applicability of this method away from a specific ship, allowing it to be applied to ships of various tonnages and types. [ABSTRACT FROM AUTHOR]

The premise of analyzing and researching robot technology is to establish a proper mathematical model and then to solve it with kinematics. In this study, a self-developed humanoid hydraulically driven dual-arm robot is taken as the research object, and the DH (Denavit–Hartenberg) parameter method and the rotational exponential formula (POE) are used to solve the kinematics of the robot. The calculation results are verified by simulation. The advantages and disadvantages of the two methods are analyzed. The differences between the two methods are compared. It lays a foundation for other scholars to choose mathematical models when analyzing the mechanism in the future. [ABSTRACT FROM AUTHOR]

We apply time-domain spectroscopy (THz) imaging technology to perform nondestructive detection on three industrial ceramic matrix composite (CMC) samples and one silicon slice with defects. In terms of spectrum recognition, a low-resolution THz spectrum image results in an ineffective recognition on sample defect features. Therefore, in this article, we propose a spectrum clustering recognition model based on t-distribution stochastic neighborhood embedding (t-SNE) to address this ineffective sample defect recognition. Firstly, we propose a model to recognize a reduced dimensional clustering of different spectrums drawn from the imaging spectrum data sets, in order to judge whether a sample includes a feature indicating a defect or not in a low-dimensional space. Second, we improve computation efficiency by mapping spectrum data samples from high-dimensional space to low-dimensional space by the use of a manifold learning algorithm (t-SNE). Finally, to achieve a visible observation of sample features in low-dimensional space, we use a conditional probability distribution to measure the distance invariant similarity. Comparative experiments indicate that our model can judge the existence of sample defect features or not through spectrum clustering, as a predetection process for image analysis. [ABSTRACT FROM AUTHOR]

Transient receptor potential vanilloid subtype 1 (TRPV1) is a polymodel sensory receptor and can be activated by moderate temperature (≥ 43 °C). Though extensive researches on the heat-activation mechanism revealed some key elements that participate in the heat-sensation pathway, the detailed thermal-gating mechanism of TRPV1 is still unclear. We investigate the heat-activation process of TRPV1 channel using the molecular dynamics simulation method at different temperatures. It is found that the favored state of the supposed upper gate of TRPV1 cannot form constriction to ion permeation. Oscillation of S5 helix originated from thermal fluctuation and forming/breaking of two key hydrogen bonds can transmit to S6 helix through the hydrophobic contact between S5 and S6 helix. We propose that this is the pathway from heat sensor of TRPV1 to the opening of the lower gate. The heat-activation mechanism of TRPV1 presented in this work can help further functional study of TRPV1 channel. [ABSTRACT FROM AUTHOR]

The present study aimed to investigate the role of Forkhead box protein C2 (Foxc2) in oxidized low-density lipoprotein (ox-LDL)-induced macrophages and identify the potential mechanisms. RAW264.7 cells, the murine macrophage cell line, were stimulated by ox-LDL, and cell proliferation was examined. The levels of inflammation- and oxidative stress-related markers were detected using kits after induction with ox-LDL. Subsequently, the expression of Foxc2 was measured using Western blotting. After transfection with Foxc2 pcDNA3.1, intracellular lipid droplets were examined using oil red O staining. The levels of total cholesterol (TC), free cholesterol (FC), inflammatory cytokines, and oxidative stress markers were determined. Moreover, apoptosis of RAW264.7 cells was detected using flow cytometry, and apoptosis-related proteins were measured using Western blotting. Angiopoietin-like protein 2 (Angptl2) was predicted as a target gene of Foxc2. Therefore, the expression of Angptl2 was examined after Foxc2 overexpression in ox-LDL-induced RAW264.7 cells. Then, the changes of intracellular lipid droplets, TC, FC, inflammatory cytokines, oxidative stress factors, and cell apoptosis were detected after Angptl2 overexpression or co-transfection with Foxc2 and Angptl2 pcDNA3.1. The results revealed that ox-LDL induction inhibited proliferation of RAW264.7 cells and promoted the release of inflammatory factors. Importantly, the expression of Foxc2 was obviously decreased after stimulation by ox-LDL. Foxc2 overexpression suppressed lipid accumulation, TC, FC levels, inflammation, oxidative stress, and apoptosis induced by ox-LDL, whereas these inhibitory effects were relieved after co-transfection with Angptl2 pcDNA3.1. These findings demonstrated that Foxc2 can alleviate ox-LDL-induced lipid accumulation, inflammation, and apoptosis of macrophage via regulating the expression of Angptl2. [ABSTRACT FROM AUTHOR]

Thermally induced elongation of a screw is the primary cause of deterioration in the positioning accuracy of half-closed-loop screw systems in machine tools. The failure mode of ball-screw feed-drive systems in relation to the positioning accuracy is defined as the response error of the carriage exceeding the axial tolerance. It is still challenging to accurately predict the thermal errors using conventional methods because the randomness of the influencing factors is not considered. This paper presents an improved random thermal network model subjected to dynamic thermal excitation for calculating real-time transient temperatures of ball-screw systems. Furthermore, a time-varying reliability model is proposed for estimating the gradual reliability of the thermally induced positioning accuracy of ball-screw systems with random thermal boundary parameters using the random thermal network. A ball-screw system of a computerized numerical controlled lathe is used as an example to show the practical application of the proposed model. Repeated experiments demonstrate the accuracy retaining ability and robustness of this method. This work provides the theoretical and practical method for real-time monitoring of the positioning accuracy reliability index for ball-screw systems and it has high accuracy considering the random parameters. • An improved random thermal network model subjected to dynamic thermal excitation was presented. • This method can obtain key point transient temperatures of ball-screw systems. • A time-varying positioning accuracy model for screw systems was proposed using random thermal network. • This model can quickly and accurately predict positioning accuracy. [ABSTRACT FROM AUTHOR]

The ball screw system operates under the coupling condition of external loads, preloads, and thermal loads, and its thermo-mechanical characteristics significantly affect its dynamics performance. Therefore, a thermal-mechanical real-time dynamics model is necessary. In this work, the screw systems thermo-mechanical coupling mechanism was first analysed. Second, a new dynamic thermal network model for the screw system with moving heat excitation was proposed using the position of the moving nut obtained by FANUC Open CNC API Specifications (FOCAS), which can rapidly determine the transient temperature field. Based on this model, a new thermo-mechanical coupling real-time dynamics model of the screw system was established. The influence of temperature on dynamics characteristics was analysed using the dynamics model, and the results showed that the system preload caused by thermal elongation of the screw decreases with an increase in temperature. The system preload caused by the thermal deformation of the bearing increases with an increase in temperature. The total preload of the system depends on the interaction between the thermal deformation of the screw and the axial thermal deformation of the bearing. Additionally, the system stiffness and natural frequency variation relative to the increase in temperature and position of the carriage were obtained. Thermo-mechanical dynamics performance experiments of the feed system were carried out to validate the effectiveness of the proposed model. [ABSTRACT FROM AUTHOR]

Consider the generalized dispersive equation defined by (*) { i ∂ t u + ϕ (− Δ) u = 0 , (x , t) ∈ R n × R , u (x , 0) = f (x) , f ∈ S (R n) , where ϕ (− Δ) s is a pseudo-differential operator with symbol φ(|ξ|). In the present paper, assuming that φ satisfies suitable growth conditions and the initial data in Hs(ℝn), we bound the Hausdorff dimension of the sets on which the pointwise convergence of solutions to the dispersive equations (*) fails. These upper bounds of Hausdorff dimension shall be obtained via the Kolmogorov-Seliverstov-Plessner method. [ABSTRACT FROM AUTHOR]

Nowadays, datasets are always dynamic and patterns in them are changing. Instances with different labels are intertwined and often linearly inseparable, which bring new challenges to traditional learning algorithms. This paper proposes adaptive hyper-sphere (AdaHS), an adaptive incremental classifier, and its kernelized version: Nys-AdaHS. The classifier incorporates competitive training with a border zone. With adaptive hidden layer and tunable radii of hyper-spheres, AdaHS has strong capability of local learning like instance-based algorithms, but free from slow searching speed and excessive memory consumption. The experiments showed that AdaHS is robust, adaptive, and highly accurate. It is especially suitable for dynamic data in which patterns are changing, decision borders are complicated, and instances with the same label can be spherically clustered. [ABSTRACT FROM AUTHOR]

BACKGROUND: Rapid and accurate diagnosis of nitrogen (N) status in field crops is of great significance for site‐specific N fertilizer management. This study aimed to evaluate the potential of hyperspectral imaging coupled with chemometrics for the qualitative and quantitative diagnosis of N status in tea plants under field conditions. RESULTS: Hyperspectral data from mature leaves of tea plants with different N application rates were preprocessed by standard normal variate (SNV). Partial least squares discriminative analysis (PLS‐DA) and least squares–support vector machines (LS‐SVM) were used for the classification of different N status. Furthermore, partial least squares regression (PLSR) was used for the prediction of N content. The results showed that the LS‐SVM model yielded better performance with correct classification rates of 82% and 92% in prediction sets for the diagnosis of different N application rates and N status, respectively. The PLSR model for leaf N content (LNC) showed excellent performance, with correlation coefficients of 0.924, root mean square error of 0.209, and residual predictive deviation of 2.686 in the prediction set. In addition, the important wavebands of the PLSR model were interpreted based on regression coefficients. CONCLUSION: Overall, our results suggest that the hyperspectral imaging technique can be an effective and accurate tool for qualitative and quantitative diagnosis of N status in tea plants. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Niacin is currently the most effective drug that increases HDL-C levels. Apolipoprotein M (ApoM) in humans is mainly found in plasma high-density lipoprotein (HDL). Little is known about the role played by niacin in ApoM expression. In this study, the effects of niacin on ApoM expression were assessed as well as the associated mechanism. Human liver cancer cell line HepG2 was treated with niacin alone or with liver X receptor-α (LXRα) inhibitor at multiple concentrations. The mRNA and protein expression of ApoM were assessed by qRT-PCR and western blotting. Specific LXRα shRNA was transfected into HepG2 cells to further evaluate the regulatory effects of LXRα on ApoM. An in vivo model was also established to investigate the LXRα inhibitor on the mouse ApoM levels. The comparisons among groups were evaluated using one-way ANOVA and Student-Newman-Keuls test. It was revealed that in HepG2 cells, niacin dose-dependently increased ApoM gene and protein expression levels. Niacin-induced upregulation of ApoM was attenuated by an LXRα inhibitor or LXRα shRNA, indicating that LXRα mediated this effect. Moreover, niacin treatment resulted in increased LXRα mRNA levels, in vivo and in vitro; niacin treatment resulted in increased ApoM gene and protein expression levels in mice. In conclusion, niacin upregulates ApoM expression by increasing LXRα expression in vivo and in vitro. [ABSTRACT FROM AUTHOR]

Large-bore natural gas reciprocating generator engines will play crucial roles in future low-carbon energy systems. Knock, as an abnormal combustion phenomenon, is a bottleneck for long time to restrict the engine performance improvement. Development and application of the reliable knock model can contribute the predictive engine control and optimization to further improve the engine efficiency and performance. The biggest challenge of developing the predictive knock model is the stochastic nature of the knock phenomenon. To bridge the technological gap, this study aims to develop a novel predictive knock model for a large-bore natural gas engine and showcase its application for co-optimization of the engine design and control parameters, together with the machine learning. The knock model, taking the effects of hot spots heat release rate and energy density into account, is calibrated by the statistical phenomenological knock factor. The 1-D engine simulation model embedded with the knock model is built and calibrated. The data-driven model based on machine learning is developed and used to predict the relation between the key parameters and the engine performance. The genetic algorithms are employed to achieve the multi-objectives global optimization of geometric compression ratio, Miller degree and other control parameters of the engine to reduce the exhaust gas temperature and improve the engine performance. The co-optimized results show that the engine exhaust gas temperature can be remarkably lowered and the indicated thermal efficiency is increased by 1–3% depending on the operational conditions, without degrading the engine power output and increasing the exhaust NOx emissions. • This study collected and analyzed the knocking characteristics of the large-bore natural gas engine. • A phenomenological knock model was developed on the large-bore natural gas engine. • Using machine learning coupling with genetic algorithm, the indicated thermal efficiency of the large-bore natural gas engine can increase 3.1% and exhaust gas temperature can decrease nearly 80 K. [ABSTRACT FROM AUTHOR]

Maritime transport has been critical for the world economy and trade for centuries. Greenhouse gases and their environmental impacts are significant contributors to global warming and climate change and have compelled authorities to take substantial steps toward decarbonizing the energy system. Since then, the International Maritime Organization, policymakers, classification societies, shipping companies, and related stakeholders have been increasingly concerned about the environmental impacts of carbon-based fuels. Green ammonia as an energy vector is considered one of the top contenders for future energy systems. However, gaps remain in the literature regarding environmental impact assessment and usage. This study assessed the environmental impacts and performance of a newly built green ammonia-powered, very large oil and chemical tanker designed for the Atlantic Ocean route from Rotterdam to New York Port. This life cycle assessment study considers a tanker's entire transport life cycle from its manufacturing process to the production, material transportation, energy required for manufacturing, operation, maintenance, disassembly, scrap processing, and using green ammonia as a marine fuel. Performed an environmental impact assessment using IPCC, Environmental footprint, and ReCiPe midpoint Hierarchist (H) methodologies for five broad impact groups: Eutrophication, ozone, Climate change, Human and Ecotoxicity, and analyzed green ammonia process impacts. This study performed a comparative environmental performance assessment of HFO, LNG, blue ammonia, and green ammonia using impact categories such as GWP 100 and GTP 100. Green ammonia exhibited the most substantial negative percentage difference values (higher than −90%) per tonne-kilometer, indicating a lower environmental impact than all fuels in both categories. Adequately managing the ammonia-powered marine energy system would be indispensable for reducing environmental footprints and successfully lowering carbon, nitrogen oxide, and ammonia-based emissions. [Display omitted] • Ammonia is regarded as a clean alternative fuel for decarbonized tanker operations. • Performed the complete transport LCIA study of a green ammonia-powered tanker. • Toxicity, ozone depletion, eutrophication, and process impacts were investigated. • Green ammonia exhibited a lower environmental impact than HFO in GWP 100 and GTP 100. • Adequate management and risk assessment of the ammonia-powered energy system would be essential. [ABSTRACT FROM AUTHOR]

• Alkylbenzenes are pyrolyzed to investigate the side-chain effect on particles and PAHs. • Pyrolysis of ethylbenzene shows the highest sooting propensity. • Particle nucleation is highly related to the variety of PAHs. • Long-side chains of alkylbenzene suppress the particle and PAH formation. The 5 linear alkylbenzenes, i.e., toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, and n-pentylbenzene as fuels underwent pyrolysis at temperatures from 950 to 1450 °C in a flow reactor. Measurements of particle number size distribution, 11 monocyclic aromatic hydrocarbons, and 3 groups of polycyclic aromatic hydrocarbons (20 unsubstituted PAHs, 5 aliphatic-bridged PAHs, and 10 methyl PAHs) during the pyrolysis of linear alkylbenzenes were conducted. Results showed that the increase in side chain length suppressed the formation of particles, but ethylbenzene produced the highest particle mass and most extensive particle number size distribution. Total particle peak number concentrations exhibited a rise-then-fall trend (peaking at a critical temperature of 1050 °C) with increasing temperature regardless of the side chain length, indicating that high temperature promoted a transition from nucleation to agglomeration and coagulation. Total PAH mass concentrations were ranked in the same order with the variation of side-chain length as particle mass and peak number concentrations, indicating that soot nucleation was highly related to total PAH mass concentrations. Unsubstituted PAHs accounted for most PAHs while substituted·PAHs, including aliphatic-bridged PAHs and methyl PAHs presented 1–2 orders of magnitude less than the corresponding unsubstituted PAHs, probably distinct thermal stability and reactivity led to different growth routes between unsubstituted and substituted PAHs. Increasing the temperature from 950 to 1250 °C, the formation of high molecular weight PAHs was promoted. while a drop of high molecular weight fractions was observed above 1350 °C, which is attributed to the suppression of the formation, as well as their conversions of high molecular weight PAHs to heavier unidentified PAHs or soot. Among the test alkylbenzene fuels, the fuels with a long side chain benefit from the reduction of particles and PAHs. Furthermore, carbon atoms in aromatic rings are dominant sources of large PAHs and particles, while the carbon atoms in aliphatic side chains mainly form gas species. [ABSTRACT FROM AUTHOR]

Pyrolysis of three practical fuels, i.e., petroleum diesel (PD), diesel from direct coal liquefaction (DDCL), and diesel from indirect coal liquefaction (DICL) were conducted at temperatures from 950° to 1450 °C in a flow reactor. The effect of temperature and fuel components on soot formation were investigated through measurement of particle volatility, size distribution (PSD), and monocyclic/polycyclic aromatic hydrocarbon (MAH/PAH) profiles. DDCL and DICL were mainly composed of cycloalkane and paraffin, respectively, and both of them were almost free of aromatics compared with PD. Results showed that pyrolysis of DDCL produced the highest particle mass concentration and broadest PSDs, followed by PD and DICL, indicating that cyclic and aromatic components had a strong promote effect on sooting tendency. ∑PAH mass concentrations of practical fuels followed the same order of DDCL > PD > DICL as particle mass concentrations and PSDs, and DDCL formed the highest ∑PAHs at a lower temperature (1050 °C) compared to that of PD (1150 °C) and DICL (1250 °C), attributing to the different pyrolysis routes of these fuel components. The chemical kinetic simulation revealed that the fuel components mainly influenced benzene formation below 1150 °C, where nucleation effect was dominant in particle behaviors. For all tested fuels, 3–4 ring PAHs / alkyl PAHs exhibited the highest mass concentrations at the whole temperature range, suggesting a primary contribution to particle nucleation. The fraction of high molecular weight PAHs showed a rise-then-fall trend, and the decrease of corresponding fractions above 1250 °C could be ascribed to their accelerated conversion to soot. Particles and PAHs showed a high correlation at the whole temperature range for tested fuels, and two-stage pyrolysis related to temperature was verified by varieties of particle and PAH characteristics. According to analytical results obtained in this study, DICL has the potential to be applied in low-temperature-combustion engines to control particle and PAH emissions. • Three practical fuels, including PD, DDCL, and DICL, were pyrolyzed in a flow reactor. • Effect of fuel structure on the particle and PAH formation was discussed. • The correlation between particles and PAHs along a varying temperature was analyzed. • DICL has the potential for controlling particle and PAH emissions. [ABSTRACT FROM AUTHOR]

The positioning precision of the ball screw system in machine tools is primarily affected by the thermal deformation of the screw. Hence, the adaptive prediction method must be established to calculate thermal errors of the ball screw system. First, based on heat transfer theory, a new adaptive moving thermal network model of the screw system with moving thermal excitation and varying operating conditions is proposed. The time-serial data of kinematic-pair representative temperatures and the time-serial position data of the moving nut are used as inputs. This adaptive model is used to determine the temperatures of the key elements in the supporting bearings and those of the moving nut and key points of the screw shaft. Further, the heat generation rate of each kinematic pair can be obtained simultaneously. Furthermore, a real-time prediction method of thermal errors of the screw system with moving thermal excitation under various operating conditions is presented. The effectiveness and robustness of the real-time prediction method of thermal errors was verified experimentally. This method is suitable for the rapid prediction of thermal errors of screw systems by monitoring the real-time kinematic-pair representative temperatures and real-time position of the moving nut. • A new adaptive moving thermal network model for a screw system is proposed. • Based on the moving network model, the real-time thermal error model is proposed. • The heat generation rates of the heat sources are simultaneously identified in real-time. • The presented model can be used for the multiple varying working conditions. • This model has self-adaptive ability and robustness. [ABSTRACT FROM AUTHOR]

The aim of the present study was to explore the association between apolipoprotein M (ApoM) and adiponectin, and the underlying mechanism, via observation of ApoM expression in an obese mouse model. For in vivo experiments, mice were randomly distributed into four groups: Control group, obese group, obese group treated with adiponectin, and normal group treated with adiponectin. Body weight, plasma adiponectin, blood glucose and fasting insulin were measured and visceral adipose tissue was weighed at the end of the experiment. ApoM and transcription factor forkhead box A2 (Foxa2) mRNA expression in the mouse liver was evaluated and the protein level of ApoM detected. For in vitro experiments, an insulin-resistant (IR) hepatic cell model was established by inducing the HepG2 cell line with a high concentration of insulin. Following treatment with adiponectin, changes in ApoM and Foxa2 mRNA expression and ApoM protein expression were evaluated in the control and IR HepG2 cells. Results demonstrated that compared with the control group, body weight, visceral adipose tissue weight, blood glucose, fasting insulin and insulin-resistance index (HOMA-IR) were significantly increased in the obese group, whilst plasma adiponectin, ApoM mRNA expression, Foxa2 mRNA expression and ApoM protein in the mouse liver were all significantly decreased. Following intervention with adiponectin in obese mice, blood glucose, insulin and HOMA-IR were significantly decreased, whilst plasma adiponectin, ApoM mRNA expression, Foxa2 mRNA expression and ApoM protein were all significantly increased. However, no significant difference was observed in visceral adipose tissue weight following the intervention of adiponectin in obese mice. In vitro, in the absence of intervention, ApoM and Foxa2 mRNA expression and ApoM protein expression were significantly lower in IR HepG2 cells compared with HepG2 cells. Following intervention with adiponectin on IR HepG2 cells, ApoM and Foxa2 mRNA expression and ApoM protein expression were significantly increased. However, the intervention did not have any effect on HepG2 cells. In conclusion, intervention with adiponectin elevated ApoM mRNA expression, potentially via relieving IR and upregulating Foxa2 mRNA expression. [ABSTRACT FROM AUTHOR]

Ball screws used for high-speed feed systems generate friction heat, which affects the preload and supporting system stiffness, and further, the dynamic characteristics of the screw system are modified and negative effects on the positioning accuracy are produced. Therefore, a thermal dynamic model for investigating dynamic performance variation with temperature is needed. First, a new dynamic temperature model of a hollow cylinder with varied heat flow was proposed based on the heat transfer theory. By using the thermocouples to read the real-time surface temperatures of heat sources, this model can be used to obtain the real-time temperature field of the supporting bearings and nut, and by using the FOCAS function to read the real-time position of nut, a finite difference heat transfer model with real-time moving heat sources was established. Based on this model, the dynamic thermally induced preload and stiffness models of the system were obtained. Second, a real-time thermal dynamic model of the ball screw system was achieved. Finally, an inverse identification method of the heat excitation was proposed. Through measuring dynamic characteristics of the feed system in machine tools, the real-time thermal dynamic models of the screw system were validated. It provided the theoretical and practical foundation for real-time monitoring and controlling of dynamic characteristics of preloaded ball screw systems. [ABSTRACT FROM AUTHOR]

Introduction: Kinesin-1 motor is a molecular walking machine constructed with amino acids. The understanding of how those structural elements play their mechanical roles is the key to the understanding of kinesin-1 mechanism. Methods: Using molecular dynamics simulations, we investigate the role of a helix structure, α4 (also called switch-II helix), of kinesin-1's motor domain in its processive movement along microtubule. Results: Through the analysis of the structure and the interactions between α4 and the surrounding residues in different nucleotide-binding states, we find that, mechanically, this helix functions as a shaft for kinesin-1's motor-domain rotation and, structurally, it is an amphipathic helix ensuring its shaft functioning. The hydrophobic side of α4 consists strictly of hydrophobic residues, making it behave like a lubricated surface in contact with the core β-sheet of kinesin-1's motor domain. The opposite hydrophilic side of α4 leans firmly against microtubule with charged residues locating at both ends to facilitate its positioning onto the intra-tubulin groove. Conclusions: The special structural feature of α4 makes for an effective reduction of the conformational work in kinesin-1's force generation process. [ABSTRACT FROM AUTHOR]

Laser induced breakdown spectroscopy (LIBS) is an effective technique to obtain quantitative concentration information for the fuel injection and combustion processes. Practical applications of fuel injection and combustion usually involve a wide range of ambient pressures and temperatures, but understanding of the influence of these parameters on LIBS is far from adequate. The objective of this paper is therefore to investigate the pressure and temperature effects on LIBS over a wide range for gas concentration measurements, and further correct these effects to improve the measurement accuracy. The calibrations at various ambient pressures show that the peak intensity ratios (PIRs) exhibit better linear correlations with the equivalence ratios than the area intensity ratios (AIRs) for H656/N746. The intensities of H656 and N746 are remarkably influenced by the gas pressure due to the combined effects of varied gas density and self-absorption. While the PIR of H656/N746 depends greatly on gas pressures from 0.3 to 1.0 bar, the gas pressure effects on the PIR of H656/N746 are very slight at gas pressure above 1.0 bar. The effects of gas temperature on the PIR of H656/N746 are investigated at both constant gas pressure and constant gas density. The results show that the temperature differences between the calibrations and test conditions would significantly degrade the measurement accuracy, especially at low gas pressures. Then, a novel method to correct the gas temperature effects on LIBS for gas concentration measurements is proposed, based on a linear correlation between the PIR of H656/N746 and the gas temperature, with the gas temperature estimated by the full width at half maximum (FWHM) of H656. Fig. 1 Effects of the gas pressure and temperature on the intensities of H656 and N746, and the PIR of H656/N746 (ϕ = 0.95). Unlabelled Image • The PIRs of H656/N746 exhibit better linear correlations with the equivalence ratios than the AIRs. • The gas temperature significantly affects the PIR of H656/N746 at both constant pressure and constant density. • The gas temperature effects is corrected based on the linear correlation between the PIR and the gas temperature. • A novel method to estimate the gas temperature by using the FWHM of H656 is proposed. [ABSTRACT FROM AUTHOR]

Abstract A novel ambient tracer LIF technique with addition of tracer into ambient gas is proposed in this study to quantitatively measure the two dimensional (2-D) fuel concentration distribution in high-pressure gas jets. Firstly, the fundamental principle of the ambient tracer-LIF technique is described, and the equation of fuel concentration in a jet is deduced from the ambient fluorescence intensity. In the ambient tracer-LIF technique, the on-site calibration can be performed, and much more degrees of freedom in selection of tracers or target fuels can be achieved in principle. Then, the experiments are carried out with the high pressure gas injected into the environment doped with acetone in an optical accessible constant volume vessel. The fluorescence in the ambient is induced by using the 266 nm laser, and is recorded by the ICCD camera. The dedicated image processing is implemented to reduce the uncertainty and obtain the quantitative fuel concentration distribution in the jet. The uncertainties of the measurement results are evaluated, including both the systematic and random errors. The uncertainty propagation analysis shows that the measurement uncertainty increases with the local fuel concentration decreasing, and at the boundary regions of the jet, where the mixture is over lean, the relative uncertainty goes up to 26%. Finally, the temporal variations of the fuel concentration distribution in the gas jet are presented, and the effects of injection pressure are discussed. These results are believed to be valuable for development of numerical models and combustion system designs. Graphical abstract Fig. 1 The temporal variations of fuel molar fraction (X) and equivalence ratio (ϕ) distributions in the jets by (a) single shot and (b) average of 10 shots (P inj = 90 bar, P a = 1.0 bar, T a = 293 K, τ = 0.9 ms). Image 105190 Highlights • The equation to calculate the equivalence ratio in the jet in the ambient tracer-LIF technique are derived. • The on-site calibration is performed to eliminate the laser shot-to-shot energy variation. • The relative uncertainties of measured results are closely related to the local fuel concentration. • Higher injection pressure leads to higher equivalence ratio and more widely-distributed combustible mixture in the jet. • The larger standard deviation of the equivalence ratio mainly exists at the jet edges and the jet tips. [ABSTRACT FROM AUTHOR]

Highlights • Diesel spray penetration processes can be clarified into three stages. • The 0-D model for spray tip penetration after the EOI is further developed. • The 0-D model for spray tail penetration after the EOI are newly formulated. • The spray tail penetration is independent of the fuel injection pressure. • The caculated results by the new models agree very well with the experimental ones. Abstract Zero-dimensional (0-D) modeling of spray development plays increasingly significant roles in the model-based optimization of parameter designs and control strategies in diesel engine systems. Partially premixed low temperature diesel combustion that has been deemed essential in simultaneous reductions in the nitrogen oxides (NOx) and soot emissions usually features ignition occurrence after the end of fuel injection (EOI). However, so far modeling of the spray development after the EOI is far from adequate. Particularly, a theoretical model for the spray tail penetration is still absent. The objective of this paper is therefore to develop the 0-D model for both diesel spray tip and tail penetrations. The model of spray tip penetration after the EOI is based on the existing models, and the model constant is further developed. The mathematical expression of spray tail penetration is newly deduced with the discrete control volume method. These models are validated against the experimental spray data with varied ambient densities, injection pressures and nozzle hole diameters using the high-speed shadowgraphy and the constant volume chamber. The calculated results by the models agree very well with the experimental ones. The spray tip penetration exhibits a t dependence at the initial stage of injection, a t 1/2 dependence at the later stage, and a (t − t i)1/4 dependence after about two injection durations from the start of injection (SOI). While the spray tail penetration is independent of the fuel injection pressures, it exhibits a (t − t i)1/2 dependence. Since the spray tail penetration rate is rather slower than the spray tip, the spray development after the EOI shows a trend with remarkable length extension, causing the quick fuel-air over mixing. These results are believed to be valuable reference for researchers or engineers who are considering the model-based design and control strategy development for diesel engine systems. [ABSTRACT FROM AUTHOR]

Abstract This study aims at providing new insights into the soot formation and oxidation processes in diesel spray jet flames under the diesel-like conditions. Soot particles are sampled within a reacting diesel jet spray flame in a constant-volume combustion chamber under diesel-like high-temperature and pressure ambient conditions. The experiments are conducted with an injector hole of 0.28 mm and injection mass of 30 mg per shot. Soot particles at different locations along the axis of the diesel jet flame are sampled by a thermophoretic probe, and the variation of soot morphology and nanostructure of the sampled soot particles along the axial location in the flame is analyzed by using the transmission electron microscopy (TEM). At upstream of the jet flame, large "liquid-like" particles are observed in the TEM images. As these particles are delivered to the downstream, (1) there are many immature primary particles formed on the surface of large "liquid-like" particles, and (2) they are carbonized into the larger soot aggregates with the matured structure, and then at last, (3) the larger soot aggregates gradually break up into the smaller particles with relatively compact structure. Both the diameter of primary particles and radius of gyration of the soot aggregates decrease as the distance between the injector nozzle tip and the center of TEM grid is increased, while the opposite trend is found in the behavior of the fractal dimensions of soot aggregates. The high resolution TEM images show that the soot primary particles exhibit the turbostratic state at the upstream of the jet flame, while more matured structures with the graphitic crystallite in outer shell and several fine particles in the inner core are observed as the sampling distance from orifice is increased. The average fringe length increases while the average tortuosity and separation decrease with the distance from the nozzle. These results suggest that the mechanism of mature soot aggregates generated directly from the large "liquid-like" particles should be one of the ways of soot particle formation along the axis of diesel jet flames. [ABSTRACT FROM AUTHOR]

Epoxy resin carbons are of high strength, high temperature resistance, and corrosion resistance, which are widely used as the precursor of carbon composite materials. However, the applications of epoxy resin carbons are greatly limited for the characteristic of non-graphitization and low char yield (22 wt%). In this paper, coal tar pitch was used to modify epoxy resin carbons via a simple heating mixing, pyrolysis and high temperature graphitization. The results show that the coal tar pitch content and heat treatment temperature can improve the ordered graphite carbon content. As the coal tar pitch content increase, the ordered graphite carbon content of modified epoxy resin carbon increase after 3000 °C graphitization for 0.5 h. Particularly, the graphitization degree of epoxy resin carbon and 40 wt% coal tar pitch modified epoxy resin carbon are 8.42 % and 44.21 %, respectively. The grain size (L c = 13.84 nm) and grain stacking height (L a = 7.79 nm) of 40 wt% coal tar pitch modified epoxy resin carbon are bigger than epoxy resin carbon (L c = 3.44 nm, L a = 3.45 nm). The ordered coal tar pitch graphite carbon and disordered epoxy resin amorphous carbon are evenly distributed in the modified epoxy resin carbon, indicating a good comparability of coal tar pitch and epoxy resin. Besides, the entangling carbon ribbon are observed in the epoxy resin carbon after graphitization at 3000 °C. With the increase of coal tar pitch content, the content of carbon element, aromatic ring number, the char yield and thermal decomposition temperature of modified epoxy resin increased. Moreover, the char yield of expoxy resion modified by 50 wt% coal tar pitch is 42 wt%, almost two times higher than that of epoxy resin (22 wt%). The increased char yield of modified epoxy resin mainly inherited the high char yield of coal tar pitch (50 wt%) and the chemical crosslinking weight gain. More interesting, the chemical crosslinking weight gain reaches the maximum value of 15 wt% when the content of coal tar pitch is 40wt%. The reason for that is the possible chemical crosslinking reaction can be occured by the epoxy group and hydroxyl group within epoxy resin and carboxyl group and phenolic hydroxyl group within coal tar pitch. This study provides some theory foundation for the future application of epoxy resin carbon composite materials. [Display omitted] • A simple process for preparation evenly mixed modified epoxy resin carbon. • Coal tar pitch can improve the thermal stability, char yield and chemical crosslinking weight gain of modified epoxy resin. • Possible chemical crosslinking reaction of epoxy resin and coal tar pitch was put forward. • Coal tar pitch and heat treatment temperature controlled epoxy resin carbon graphite structure. [ABSTRACT FROM AUTHOR]

Azipod propulsion has revolutionized the future of ship propulsion and maneuvering operations with over 20 years of experience, eventually improving ship safety, reliability, energy efficiency, and overall vessel performance. However, it consists of technically complex machinery systems; its breakdown can result in many potential failures with severe repercussions. In this work, an accident-based dynamic risk assessment study of the Cruise ship pod propulsion system has been carried out. It is based on the real-ship accident of the Norwegian Star, which resulted in the loss of ship propulsion. When historical accident statistics are limited, traditional methods fail to address the uncertainty, dynamic environment, and quantitative risk assessment problems. The goals include avoiding worst-case scenarios by illustrating the progression of dynamic change in risk and establishing the Bayesian network framework for dealing with uncertainty more effectively. Interval type-2 Fuzzy expert system is integrated with the dynamic Bayesian network and bow-tie model for quantitative risk assessment, which laid the groundwork for the subsequent hazard identification and quantitative risk assessment. This accident network summarizes how pod machinery operational failures can cause accidents. The estimated sensitive machinery nodes such as Main motor failure, propulsion system, and power system failure are the leading causes of pod propulsion system failures on board cruise vessels. Risk analysts and decision-makers in the marine and offshore engineering industry can use the suggested model as a decision support tool to considerably reduce and eliminate potential failures, improving the ship's safety and system reliability. [Display omitted] • A Dynamic Bayesian Network model for pod propulsion accidents is proposed. • Used integrated IT-2 Fuzzy-Dynamic Bayesian network approach for risk analysis. • The DBN method was implemented for pod machinery accidents using different scenarios. • Quantitative risk assessment during the worst-case scenarios was performed. • Failures of the Main motor, propulsion system, and power system were the leading causes. [ABSTRACT FROM AUTHOR]

Black carbon (BC) emissions from shipboard diesel engines are the next potentially important issue of interest to the International Maritime Organization (IMO) and are considered to have a significant impact on the climate environment and human health. However, theories and technologies regarding the mechanisms of black carbon formation, oxidizing and influencing factors, emission detection methods, and abatement techniques are still missing in science and engineering. This paper provides a comprehensive overview of relevant advances in international maritime regulations, the frontier theory on formation mechanisms, comprehensive physical and chemical properties, and the potential reduction measures and control measures of emissions. These results suggest that BC is produced in the combustion flame of fuel and is related to the nucleation as well as the formation of PAHs. It helps to understand the initial generation process of black carbon and reduce its emission by studying it in detail and revealing some key factors, including micromorphology, nanostructural features, surface functional groups, oxidizing activity, size distribution, and elemental composition. Further, an in-depth understanding of the complex characteristics of BC can also help to identify viable BC measurement techniques and instrumentation for marine engines, thereby enhancing emission regulation. Overall, extensive technology can reduce BC emissions from marine diesel engines by approximately 50%. The information contained in this report can be used as a significant reference to further explore the BC formation mechanism and develop exclusive BC emission control strategies. [ABSTRACT FROM AUTHOR]

A case study of a 22‑year‑old woman who is diagnosed with neurofibromatosis type 1 (NF‑1) and Becker's nevus (BN), is presented. Topics discussed include soft skin‑colored nodules which were found initially during adolescence increased; histological examination of one of the nodules on patient abdomen revealed a tumor consisting of wavy cells and different manifestations of hamartoma arising from the differentiation of neural crest cells.

Diesel engines are widely used not only for heavy-duty vehicles such as ships and trucks but also for light-duty passenger cars, with a wide range of bore diameters. Since development of a new diesel engine is usually expensive and time consuming, the ability to accurately predict engine performance from existing models can reduce the resources and time required in the engine development procedure. However, so far knowledge on scaling diesel engines is far from adequacy, particularly for spray combustion processes. In this paper, two injectors with nozzle hole diameters of 0.11 mm and 0.14 mm are adopted for scaling fuel sprays under the non-evaporating conditions based on the three similarity rules. Firstly, the existence of similarity is theoretically analyzed in diesel fuel sprays of both free injection and impinging upon a wall. Then, the similarity of diesel injection rate is experimentally verified by using the Bosch long tube method. Finally, the similarity of spray angle, tip penetration length, excess air ratio and impinging spray characteristics are investigated under various injection pressures and ambient densities in an optically accessible constant volume vessel by the high-speed shadowgraphy. The theoretical analysis and experimental results reveal that the similarity rule keeping the injection pressure constant is more preferable for scaling the spray angle, tip penetration length and excess air ratio, while the other two similarity rules with reduced injection pressure result in narrowed spray angle and increased spray tip penetration length. With respect to the post-impingement behavior, although the spray from the large-hole nozzle impinges upon the wall later than those of the small-hole nozzles with the speed rule and the lift-off rule, the rebound height of the large-hole nozzle is higher than those by the small holes with the speed and the lift-off rule. The mechanism of the above phenomena is discussed in depth. [ABSTRACT FROM AUTHOR]

Micro-explosion of emulsified fuels has been studied on promoting the secondary break-up and improving fuel-air mixing. However, most studies are limited to atmospheric conditions, and experimental observation of micro-explosion under diesel-like conditions is rarely reported. The predictive model for the superheat limit of hydrous ethanol-diesel emulsion needs to be re-examined. In this study, firstly, with the molecular kinetics theory a mathematical model for predicting the superheat limit of hydrous ethanol diesel emulsions are established. Then, the model is verified by the experimental results of micro-explosion in the emulsion droplets. The superheat limit is independent of volume fraction of hydrous ethanol in the emulsions. The intensity of micro-explosion obeys the parabolic rule when changing volume fraction of the hydrous ethanol. The intensity of micro-explosion with the homogeneous nucleation is higher than with the heterogeneous nucleation. The emulsions of 30% and 40% hydrous ethanol exhibit the higher probability for the homogeneous nucleation than the other emulsions. Finally, the droplet behaviors of the emulsions under the diesel-like high-pressure conditions are experimentally observed. While the micro-explosions can be clearly observed for some droplets, neither the micro-explosion nor puffing are observable for most other droplets. The mechanism behind the phenomena is discussed. [ABSTRACT FROM AUTHOR]

The present study aimed to evaluate the role of the combination treatment of methylprednisolone (MP) and electroacupuncture (EA) in regeneration of nerve fibers and functional recovery in rats with spinal cord injury (SCI). Female Wistar rats were used for an SCI model by using a weight-drop hammer at levels T10 (spinal cord segment corresponding to the 10th thoracic vertebra). Four groups received different treatments for the study: SCI control, MP, MP and EA, and Sham. The growth of nerve fibers was examined by counting fluorescein positive nerve fibers. The motor functional recovery was evaluated by Basso, Beattie, Bresnahan (BBB) score, and electrophysiology analysis. We found that, compared to MP groups, there were more well-oriented and paralleled fluorescein positive nerve fibers in MP and EA group. Both latencies and amplitudes of the Motor Evoked Potential (MEP) in the combination therapy of MP and EA were higher than MP group. Additionally, recovered hindlimb movements were sustained in most rats in the MP and EA group. Our study indicated that combination therapies could become a powerful treatment for SCI in rats. [ABSTRACT FROM AUTHOR]

Corins are membrane-bound protease that regulates blood pressure by activating the natriuretic peptides. These pro-atrial natriuretic peptide convertases are essential for sodium homeostasis and normal blood pressure. CORIN variants have been identified in humans and other animals, but no studies of CORIN polymorphisms have been conducted in northeastern China. This study aims to investigate the association of 2 single nucleotide polymorphisms (SNPs) in CORIN (rs2271037 and rs3749585) with hypertension, as well as their potential interactions with some risk factors of hypertension in a Han population of northeastern China. A case-control study, including 402 patients with hypertension and 406 participants with normal blood pressure, was conducted in Liaoning province. SNP genotyping was carried out by high resolution melting (HRM) after polymerase chain reaction amplifications. Since rs3749585 is located in 3′ untranslated region (UTR) of CORIN , in silico analysis was used to predict target micro RNAs on TargetScan, miRanda, and DIANA-microT. As a result, mutant T allele in rs2271037 (odds ratio [OR], 1.693; 95% confidence [CI], 1.528-1.877; p  < 0.001) and C allele in rs3749585 (OR, 1.114; 95% CI 1.011-1.227; p  = 0.029) increased the risk of hypertension, comparing with wild G allele and T allele, respectively. Patients with genotype TT (OR, 10.209; 95% CI, 6.414-16.250; p  < 0.001) and GT (OR, 1.730; 95% CI, 1.226-2.443; p  = 0.002) have higher risk of hypertension than those with genotype GG. SNP rs2271037 was significantly associated with susceptibility to hypertension in all genetic models (dominant model: OR, 2.879; 95% CI, 2.080–3.986; p  < 0.001; recessive model: OR, 7.159; 95% CI, 4.779–10.724; p  < 0.001; additive model: OR, 1.535; 95% CI, 1.163–2.027; p  = 0.002). SNP rs3749585 was significantly correlated with hypertension susceptibility only in dominant model (OR, 1.533; 95% CI, 1.073–2.189; p  = 0.019), but not in recessive model (OR, 1.220; 95% CI, 0.906–1.644; p  = 0.191) or additive model (OR, 0.915; 95% CI, 0.694–1.205; p  = 0.527). After adjusting for age, gender, body mass index (BMI), smoking, low-density lipoprotein cholesterol, and serum sodium level in logistic models, the same statistical results were obtained. Interaction study showed the association between CORIN polymorphisms and hypertension could be changed by overweight (BMI ≥ 25 kg/m 2 ). In silico analyses implicated hsa-miR-495 as a target miRNA that potentially interacts with the 3′ UTR of CORIN . In conclusion, polymorphisms of rs2271037 and rs3749585 in CORIN were significantly associated with hypertension in a Han population of northeastern China. The mutant-type T allele of rs2271037 and C allele of rs3749585 might increase the susceptibility to hypertension in this population. [ABSTRACT FROM AUTHOR]