Bloomfield’s Concept of Meaning

Bloomfield’s book Language has long been recognized for laying down the foundation of formal descriptive linguistic analysis. However, he was criticized too often for his dismissal of serious study of meaning in linguistics. The fact is that in his 1933 book Language, a separate chapter is devoted to the discussion of meaning and some of the most important formal units of linguistic analysis introduced by Bloomfield like phoneme and morpheme could not have been properly defined without involving meaning. He forcefully challenged the contemporary popular mentalism in linguistic study, as has often been bypassed. His contention that linguistic study must start from form not meaning should not be taken at face value as neglect of meaning but in the historical context as an opposition to mentalistic subjective interpretation of meaning

Evidence of guide field magnetic reconnection in flapping current sheets

Based on current sheet flapping motion on 27 August 2018 in the dusk flank magnetotail, as recorded by instruments aboard Magnetospheric Multiscale (MMS) spacecraft, we present the first study of guide field reconnection observed in the flux rope embedded in kink-like flapping current sheets near the dusk-side flank of the magnetotail. Unlike more common magnetotail reconnections, which are symmetric, these asymmetric small-scale (λi ~ 650 km) reconnections were found in the highly twisted current sheet when the direction normal to the sheet changes from the Z direction into the Y direction. The unique feature of this unusual reconnection is that the reconnection jets are along the Z direction — different from outflow in the X direction, which is the more usual situation. This vertical reconnection jet is parallel or antiparallel to the up-and-down motion of the tail’s current sheet. The normalized reconnection rate R is estimated to be ~ 0.1. Our results indicate that such asymmetric reconnections can significantly enlarge current sheet flapping, with large oscillation amplitudes. This letter presents direct evidence of guide field reconnection in a highly twisted current sheet, characterized by enlarged current sheet flapping as a consequence of the reconnection outflow

Weak Solar Radio Bursts from the Solar Wind Acceleration Region Observed by Parker Solar Probe and Its Probable Emission Mechanism

The Parker Solar Probe (PSP) provides us the unprecedentedly close approach observation to the Sun, and hence the possibility of directly understanding the "elementary process" which occurs in the kinetic scale of particles collective interactioin in solar coronal plasmas. We reported a kind of weak solar radio bursts (SRBs), which are detected by PSP when it passed a low-density magnetic channel during its second encounter phase. These weak SRBs have low starting frequecny $\sim 20$ MHz and narrow frequency range from a few tens MHz to a few hundres kHz. Their dynamic spectra display a strongly evolving feature of the intermediate relative drift rate decreasing rapidly from above 0.01/s to below 0.01/s. Analyses based on common empirical models of solar coronal plasmas indicate that these weak SRBs originate from the heliocentric distance $\sim 1.1-6.1~R_S$ (the solar radius), a typical solar wind acceleration region with a low-$\beta$ plasma, and indicate that their soruces have a typic motion velociy $\sim v_A$ (Alfv\'en velocity) obviously lower than that of fast electrons required by effectively exciting SRBs. We propose that solitary kinetic Alfv\'en waves with kinetic scales can be responsible for the generation of these small-scalevweak SRBs, called solitary wave radiation (SWR)

Programmed cell death and lipid metabolism of macrophages in NAFLD

Non-alcoholic fatty liver disease (NAFLD) has now become the leading chronic liver disease worldwide with lifestyle changes. This may lead to NAFLD becoming the leading cause of end-stage liver disease in the future. To date, there are still no effective therapeutic drugs for NAFLD. An in-depth exploration of the pathogenesis of NAFLD can help to provide a basis for new therapeutic agents or strategies. As the most important immune cells of the liver, macrophages play an important role in the occurrence and development of liver inflammation and are expected to become effective targets for NAFLD treatment. Programmed cell death (PCD) of macrophages plays a regulatory role in phenotypic transformation, and there is also a certain connection between different types of PCD. However, how PCD regulates macrophage polarization has still not been systematically elucidated. Based on the role of lipid metabolic reprogramming in macrophage polarization, PCD may alter the phenotype by regulating lipid metabolism. We reviewed the effects of macrophages on inflammation in NAFLD and changes in their lipid metabolism, as well as the relationship between different types of PCD and lipid metabolism in macrophages. Furthermore, interactions between different types of PCD and potential therapeutic agents targeting of macrophages PCD are also explored

Near-Earth injection of MeV electrons associated with intense dipolarization electric fields: Van Allen Probes observations.

Substorms generally inject tens to hundreds of keV electrons, but intense substorm electric fields have been shown to inject MeV electrons as well. An intriguing question is whether such MeVelectron injections can populate the outer radiation belt. Here we present observations of a substorm injection of MeV electrons into the inner magnetosphere. In the premidnight sector at L ∼ 5.5, Van Allen Probes (Radiation Belt Storm Probes)-A observed a large dipolarization electric field (50 mV/m) over ∼40 s and a dispersionless injection of electrons up to ∼3 MeV. Pitch angle observations indicated betatron acceleration of MeV electrons at the dipolarization front. Corresponding signals of MeV electron injection were observed at LANL-GEO, THEMIS-D, and GOES at geosynchronous altitude. Through a series of dipolarizations, the injections increased the MeV electron phase space density by 1 order of magnitude in less than 3 h in the outer radiation belt (L > 4.8). Our observations provide evidence that deep injections can supply significant MeV electrons

Hydrodynamic pattern transition of droplet train impinging onto heated titanium substrates with or without nanotube coating

The impingement of ethanol droplet train on the heated titanium substrates without or with the titanium oxide nanotube coating has been experimentally investigated in close view. The coating makes the substrate with high wettability. Four distinct but steady hydrodynamic patterns are observed on both two surfaces, namely, liquid aggregation and crown periphery instability; sub-droplet splashing and crown periphery instability; splashing and stable crown; and splashing with stable angle. However, the more wetting nanotube coated substrates push the transition between the patterns to a higher temperature. The quantitatively analysis of spreading length, diameter and height of crown and stable splashing angle further proved the transitions between the hydrodynamic patterns on the two titanium surfaces. The instability at the crown periphery may result from the low surface tension of the working fluids in first and second patterns, while the crown becomes stable on the third pattern. In the fourth pattern, a sharp shift of the splashing angle from decreasing to increasing is found at the surface temperature of 323 ∘C and 404 ∘C for the bare titanium surface and the nanotube coated surface, respectively. The shift could be attributed to the emergence of Leidenfrost effect. It is found that the Leidenfrost point at the droplet train impingement on the nanotube coated surface has been remarkably delayed.Accepted versio

Design and optimization of conformal cooling channels for injection molding : a review

The recent developments in the additive manufacturing make easier and affordable the fabrication of conformal cooling channels (CCCs) compared with the traditional machining techniques. Conformal cooling channels (CCCs) achieve better cooling performances than the conventional (straight-drilled) channels during the injection molding process since they can follow the pathways of the molded geometry while the conventional channels fail. Cooling time, total injection time, uniform temperature distribution, thermal stress, warpage thickness, etc. are some of the objectives that are improved via CCC applications. However, the CCC design process is more complex than the conventional channels; therefore, computer-aided engineering (CAE) simulations have significant importance for the effective and affordable design. This review study presents the main design steps of CCCs as follows: (1) a background of the CCC fabrication process is projected, (2) the thermal and mechanical models are presented with respect to the 1D analytical model, (3) the CAE-supported design criteria are discussed for the 3D models of CCCs and relevant mold materials, (4) some of the illustrative CAE simulations are explained in detail according to the computational thermal and mechanical objectives, and (5) the single- and multi-objective optimization procedures are defined. By following the aforementioned steps, clearer and effective CAE steps can be obtained for the designers before the on-site fabrication of CCCs

Thermal and mechanical assessments of the 3D-printed conformal cooling channels : computational analysis and multi-objective optimization

Conformal cooling is an additive manufacturing-based solution and it is a rapidly developing method for reducing the cooling time of the plastic injection process. The present study investigates the thermal and mechanical performances of the 3D-printed conformal cooling channels using computational analyses and multi-objective optimization. For a real injection mold product, two different conformal cooling channel profiles, which are circular and elongated, are analyzed individually. Their cooling time, temperature non-uniformity, and pressure drop are assessed. Compared to the traditional channels, the cooling time of designed CCCs is reduced in the range of 30-60%. The cooling and fatigue life performances of the elongated channel are analyzed for different channel pathways and cross section areas. As for the circular channel, the coolant temperature, volume flow rate, and channel diameter are selected as the parameters within the ranges of 288.0-298.0 K, 1.0-10.0 L/min, and 2.1-2.5 mm, respectively. According to these parameters, the multi-objective optimization study is performed and the best trade-off point is found at the channel diameter of 2.5 mm, coolant temperature of 297 K, and the flow rate of 1 L/min when all the objectives have equal weights in the optimization problem.Accepted versio