External Zone Research Articles

Age, Growth and Otolith Microstructure of the Spotted Lanternfish Myctophum punctatum Rafinesque 1810

This study investigated, for the first time, the age and growth of the spotted lanternfish Myctophum punctatum through an analysis of otolith microstructure. A total of 377 individuals were collected from the Strait of Messina (central Mediterranean Sea), ranging between 20.3 and 73.7 mm of standard length. Their length–weight relationship was estimated, and these outputs indicated an isometric growth, for all specimens and when males and females were analysed separately. The sagittal otoliths were removed from 185 fish, although the microincrement readings were considered valid for only 173 otoliths. Microincrement counts ranged from 32 to 48 (average = 37.6) in the otolith central zone, 30 to 56 (average = 44.3) in the middle zone, and 36 to 384 (average = 165.5) in the external zone. Overall, total microincrements ranged between 106 and 469. Different growth models (Gompertz, von Bertalanffy and logistic models) were considered, to understand which one fit best in describing the growth patterns in M. punctatum. The Gompertz model was then selected as the best-fitting model and its parameters for all individuals were L∞ = 74.79, k = 0.0084 and I = 139.60.

Polyethylene/Polyamide Blends Made of Waste with Compatibilizer: Processing, Morphology, Rheological and Thermo-Mechanical Behavior.

The aim of this study was to develop a polyethylene/polyamide (R-PE/R-PA) regranulated product made from post-consumer wastes grafted with polyethylene-graft-maleic anhydride (PE-g-MAH) by reactive extrusion in a twin-screw extruder equipped with an external mixing zone. The compatibility effect of PE-g-MAH used as a modifier in R-PE/R-PA blends was evaluated by means of differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA), while the analysis of the chemical structure of this blend was carried out by Fourier transform infrared spectroscopy (FT-IR). The thermal properties, complex viscosity, and selected usage properties of R-PE/R-PA blends compatibilized with PE-g-MAH, i.e., density and water absorption, were evaluated. The morphology of the blends with and without the compatibilizer was observed by scanning electron microscopy. The R-PE/R-PA/MAH blend shows heterogenic structure, which is a result of the chemical reaction in reactive extrusion between functional groups of PE-g-MAH used as modifier and the end groups of R-PA6. The results show that the R-PE/R-PA blend with increased PE-g-MAH content showed increased hardness, stiffness, and ultimate tensile strength due to the increased degree of crystallinity. The increase in crystallinity is proportional to the improvement of the mechanical properties. Moreover, it is shown that 1 wt.% PE-g-MAH added to the R-PE/R-PA waste blend increases the interfacial interactions and compatibility between R-PE and R-PA, resulting in decreased polyamide particle size. Finally, the results show that it is possible to produce good quality regranulated products with advantageous properties and structure from immiscible polymer waste for industrial applications.

Mapping an archaeological site: Interpreting portable X-ray fluorescence (pXRF) soil analysis at Boroughgate, Skelton, UK

Integrating chemical soil analysis with visual inspection of an archaeological excavation may enhance our knowledge of anthropogenic activities from past populations. Elemental distribution of excavated soil from a medieval longhouse at Boroughgate, Skelton, UK was investigated. Soil was extracted from the surface of a longhouse and nearby ditch, analysed using portable X-Ray fluorescence (pXRF), and data were processed into elemental heat maps. The distribution and archaeological associations of magnesium, aluminium, phosphorus, sulphur, potassium, calcium, manganese, iron and zinc were assessed. Elemental concentrations were combined to produce a simplified summary that aided the interpretation of the site, including the delimitation of internal and external zones, clean and refuse zones, and potential animal occupation or waste areas. The application of pXRF was successful at visualising elemental distribution of an excavation to explore the anthropogenic associations through interpretation heat maps.

An approach for permeable boundary conditions in SPH

Smoothed Particle Hydrodynamics (SPH) has intrinsic advantages over the Finite Volume (FV) method for predicting multiphase flows, since the need for fluid phase interface reconstructions is avoided due to the natural advection of those interfaces based on the Lagrangian description of the control volumes. However, permeable boundary conditions are less straightforward to handle with SPH, even though domain inlets and outlets are needed in most engineering problems. In this work we propose a new framework for permeable boundary conditions for the Weakly Compressible SPH based on ghost particles. The major characteristics of our approach are the application of Navier Stokes Characteristic Boundary Conditions (NSCBC) and a particle mass generation and removal procedure at the boundary. This approach enables the application of non-reflective boundary conditions and redundantizes the need for advecting ghost particles from an external buffer zone to the internal domain. Additionally, the particle mass variation can exactly be balanced with the mass flux defined at the boundary. Furthermore, we are proposing a novel approach to set the ghost particle state based on an extrapolation of the state of particles located in the internal domain and on the domain boundary. We validate the proposed framework for permeable boundaries with one- and two-dimensional test cases. The major findings are as follows. Due to the particle mass generation and removal at the domain boundary, spurious oscillations are introduced due to a non-optimal particle distribution. Those oscillations are reduced in our work to an acceptable level (1×10−5 to 1×10−4 relative to the values of the fluid dynamics variables) using existing stabilization schemes as well as the aforementioned novel methods for setting ghost particle states and particle masses at the permeable boundaries. We observe a very good agreement between the solutions obtained with the presented approach and analytical as well as numerical solutions obtained with the FV method. The proposed approach for setting the ghost particle states is indispensable for achieving a perfect balance between particle mass variation and mass flux across the permeable interface as well as the steady state and the temporal accuracy of the solution. Additionally, the pressure reflectivity at the permeable boundary is found to be in a very good agreement with the theory of the NSCBC method. Furthermore, for a SPH-FV coupled simulation we could demonstrate an excellent agreement compared to the FV method as well as the capability of our approach to handle significant flow unsteadiness and gradients at the permeable coupling interfaces without the introduction of spurious flow behavior.

Late Carboniferous paleoelevation of the Variscan Belt of Western Europe

We present the first stable isotope paleoaltimetry estimates for the hinterland of the eroded Variscan Belt of Western Europe based on the hydrogen isotope ratios of muscovite from syntectonic leucogranites that have been emplaced at ∼315 Ma. We focus on the Limousin region (Western Massif Central, France) where peraluminous granites are spatially associated with strike-slip and detachment shear zones that developed as a consequence of Late Carboniferous syn- to post-orogenic extension. In this region, we show that the north-east corner of the Millevaches massif (located at the junction between brittle and ductile fault systems) represented a pathway for Earth surface-derived fluids that penetrated the crust and reached the ductile segment of the low-angle Felletin detachment zone. Using microstructural, thermometry, hydrogen isotope and 40Ar/39Ar geochronological data, we show that these Variscan meteoric fluids interacted with hydrous silicates during high temperature deformation between ∼318 and 310 Ma. For paleoaltimetry purposes, we reference our hydrogen isotope record (δD) of ancient meteoric fluids from mylonitic rocks to ∼295 Myr-old records retrieved from freshwater shark remains preserved in the Bourbon l'Archambault basin that developed in the external zones of the orogen. A ∼76‰ difference in δDmeteoric water values between the Millevaches massif (δDmeteoric water value = −96 ± 8‰) and the Bourbon l'Archambault foreland basin (δDwater value = −20 ± 6‰) is consistent with paleoaltimetry estimates of 3.4 ± 0.7 km based on a modern lapse rate of ∼-22‰/km for δDwater values. The rather large difference in δD values between the foreland basin and the continental interior suggests that the hinterland of the Variscan belt of western Europe was high enough to act as a barrier to moisture transport from the south-south-east and induce an orographic rain shadow to the north.

Mechanical Influence of Inherited Folds in Thrust Development: A Case Study from the Variscan Fold-and-Thrust Belt in SW Sardinia (Italy)

Fold-and-thrust belts have a high variability of structural styles, whose investigation provides continuous updates of the predictive models that try to better approximate the geometries recognized in the field. The majority of studies are focused on the geometry and development of folds and thrust surfaces and the amount of displacement, taking into account the role played by the involved stratigraphic succession assumed as a layer cake. We present a case study from the external zone of the Variscan fold-and-thrust belt in SW Sardinia, where it was possible to investigate the lateral and vertical variations of the mechanical properties of the involved succession, how they related to previous folding, control thrust geometry, and kinematics. In this case, the superposition of two fold systems acted as a buttress that induced extensive back-thrusting. We found that there is a close connection between the attitude of the bedding and the geometry of back thrust surfaces, shear strength during thrust propagation, and variation in the shortening amount, depending on which part of the folds were cut across. The folding-related mechanical anisotropy also seems to have induced a ductile deformation in the footwall of back-thrusts. Although the case study considers the development of back-thrust, the relations between thrust and not-layer cake geometries could also be applied to fore-thrust development.

DETERMINATION OF STRESS FIELDS FROM THE ACTION OF A DISTRIBUTED LOAD

The influence of the external deformation effect of the distributed load on the stress state in the region of the wedge-shaped twin has been established. The change in stress fields in the near-surface region containing a twin is shown, depending on the intensity, uniformity and size of the external force loading zone     &nbsp

Hydrogen production for fuel cell application via thermo-chemical technique: An analytical evaluation

Fuel cells are considered as the promising candidates for next-generation energy systems for which supplying the required hydrogen is the most important issue. Because of resource scarcity and environmental pollution associated with hydrocarbon reforming, magnesium-water combustion can be applied as an eco-friendly alternative method for hydrogen generation. This study aims to investigate magnesium combustion as a heat and hydrogen source. By proposing an asymptotic model of flame structure, the combustion of single magnesium particle is examined in which the model consists of internal and external zones and a thin reaction layer. Then, the governing equations including mass, energy, and mass fractions of species and their appropriate boundary conditions are derived and solved analytically. Afterwards, with the aid of Taylor approximation, the explicit formulas are extracted for flame location and temperature and magnesium evaporation rate. Subsequently, the effects of various parameters on combustion characteristics and hydrogen production are scrutinized. Eventually, by employing the examined model for single particle, the discrete method is applied to analyze the magnesium dust cloud combustion. The results indicate that the hydrogen production rate is higher than 10-3kg/s for the condition of d=10μm,P=1atm,Le=1 with dust concentration greater than 250mg/liter.

Absolute instability of double annular jets: local stability analysis

The paper presents the local linear stability analysis of the double annular jets. The calculations show that the first absolutely unstable helical mode can be generated in the non-swirling annular jets by the back-flow in the central recirculation zone or sufficiently strong back-flow in the external recirculation zone. The influence of the back-flow magnitude on the frequency, growth rate and eigenfunctions of the first helical mode is discussed. The calculations are completed with an analysis of the influence of the swirl intensity in the internal and external jets on the characteristics of the first absolutely unstable helical mode.

Mechanical characterization of the enamel microstructure treated with non alcoholic drinks

In previous studies, it has been shown that the microstructure of prismatic dental enamel presents differences between the external and internal zone. Radial enamel is found in the outer third of enamel and has higher microhardness values than enamel with Hunter- Schreger Bands (HSB) that occupies the inner 2/3. Our aim was to evaluate the mechanical behavior of radial enamel and HSB due the action of a non-alcoholic beverage in vitro. Longitudinal sections of dental crowns were embedded in polymer, worn and polished with sandpapers of decreasing granulation. The samples were immersed in a flavoured natural water for 12 minutes. Nanohardness tests (Triboindenter Hysitron) were performed on the radial and HSB enamel before and after the exposure to the drink. Hardness determinations "H", reduced modulus "Er" and contact depth "hc" were obtained. The percentage of reduction of hardness was determined. The values found in healthy radial enamel were H: 5.48±0.23 GPa; Er: 86.97±8.11 GPa; hc: 149.73±4.25 nm and in HSB H: 4.24±0.43 GPa; Er: 75.24±7.09 GPa; hc: 176.36±11.29 nm. After exposure to beverage, it was found in the radial enamel H: 2.22±0.31 GPa; Er: 58.73±10.79 GPa; hc: 270.29±21.22 nm, and in HSB H: 1.54±0.42 GPa; Er: 48.11±6.54 GPa; hc: 350.10±63.33 nm. After the drink action, the values of hardness of the radial enamel and HSB decreased and the trend observed in healthy enamel remained, where the highest values corresponded to the radial enamel. The percentage reduction of H in the radial enamel was 59.48% and in the HSB enamel it was 63.67%. The contact depth increased by about 50%.The decrease in hardness is related to the mineral loss produced by the acids contained in the drink. We conclude that the action of the non-alcoholic beverage produces a decrease in the mechanical properties in both the radial enamel and the HSB. The lower values in the reduced module Er indicate the formation of a superficial softened layer, the enamel with HSB being more vulnerable.

Genesis of the Donggushan tungsten polymetallic deposit, central Anhui Province: A clue of diagenetic and metallogenic system of a crustal source

• The W mineralization in the Donggushan was caused by the Late Cretaceous magmatism . • Diagenetic and metallogenic system was likely to be originated from a crustal source dominated by the Northern Dabie Terrane . • The REEs of scheelite are mainly controlled by the substitution mechanism Ca 2+ + W 6+ = REE 3+ +Nb 5+ . • The ore-forming fluids were modified by the intense fluid-rock interaction. The newly discovered large-scale Donggushan tungsten polymetallic deposit with resources of 70,000 t WO 3 and 38,000 t Mo, located at the Lujiang county, center of Anhui Province, East China. The deposit is characterized by skarn W-Mo mineralization, which is developed along the external contact zone between the biotite granites and carbonate rocks. Zircon U-Pb dating yields a Late Cretaceous age of 98.3 ± 1.6 Ma for the Donggushan biotite granite. The hidden biotite granites of Donggushan is characterized by high silica and alkali but low Mg, Fe. It is enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs: Rb, K, Th and U), but strongly depleted in heavy REEs, and high field strength elements (HFSEs: Nb, Ta and Ti), and Sr. This high-K granite has medium initial 87 Sr/ 86 Sr ratios (0.706518–0.707116) and low initial Pb isotopic ratios [( 206 Pb/ 204 Pb)i, 16.452–16.533; (207Pb/204Pb)i, 15.449–15.463; ( 208 Pb/ 204 Pb)i, 36.946.335–37.097], and is characterized by low εNd(t) and εHf(t) values (−22.1 to −16.1 and −21.3 to −15.1, respectively). All these data indicate that the Donggushan biotite granite is a high-K calc-alkaline fractionated I-type granitite. This granite may have derived from a crustal source, which is dominated by the Northern Dabie Complex (NDC) mixed with the basement materials of the Taihua Group. The magmatism in the Donggushan polymetallic deposit is quite different from those in the metallogenic belts of the Qinling-Dabie Mo belt (QDMB) and Middle-Lower Yangtze River Belt (MLYB). Based on the geochemical study of REEs of scheelite, it is proposed that the substitution mechanism of Ca2+ + W6+ = REE3+ +Nb5 + occurred during the formation of scheelite. Concentrations of Eu indicate that scheelite precipitated under the oxide conditions. The variations of the Mo concentrations might be caused by the changing of oxide reduction conditions. The Sr of the scheelite and S isotopes of pyrite in the Donggushan deposit reflect a complex magmatic-hydrothermal mineralization process within the intrusion and the country rocks.

Fault distance estimation in multiterminal HVDC systems using the Lomb-Scargle periodogram

Multiterminal high-voltage direct current (MTDC) systems still need to be improved in terms of protection to maximize their availability. In this paper, a new distance protection algorithm is proposed. The fault distance is estimated using the frequency of the DC-side voltage oscillation and the cable travelling wave speed. The frequency is estimated using the Lomb-Scargle Periodogram (LSP). The LSP can calculate a signal spectral power for arbitrary frequency values. It can also process signals with missing samples, which makes it easier to use in real-world applications when data can be lost in the communication. In the proposed algorithm, only local measurements are used, without communication. The proposed algorithm was tested in a four-terminal MTDC system and was fully selective in simulation environment. To further verify the technique’s applicability, the proposed algorithm was embedded in a digital signal controller, and was simulated in real-time. In all the tests simulated in hardware, the faults were correctly detected and identified as being internal (zone 1) or external (zone 2). The results highlighted the potential of the Lomb-Scargle Periodogram and indicated that the proposed algorithm could be used in real-world applications, adding selectivity to multiterminal DC protection schemes.

PASSENGER RAILWAY COMMUNICATION AND ATTRACTIVITY OF OUTER ZONES OF RUSSIAN MILLIONAIRE CITIES

The author interprets the transport accessibility of the outer zones of the cities and attractors located in them as the most important condition for the successful development of the city, excluding the socio-spatial segregation of the urban environment. The article reveals the role of railway in ensuring this accessibility in 14 millionaire cities in Russia. As a result, the paper studies six groups of cities according to the integral indicator. They differ in the level of development of railway communication, which connects the outer zones with each other and with the center. The most favorable situation is typical for Volgograd, Kazan and Yekaterinburg (first group), the least - for Chelyabinsk (sixth group). The author reveals essential differences within the three groups based on comparing the values of indicators of the provision of general urban attractors with railway traffic and the degree of its uniformity. Among the five cities with a high and increased level of development of railway communication, only Yekaterinburg has a relatively high and relatively uniform provision of attractors of external zones with this type of the transport. In most cities, where the level of development of railway communication is below average, it provides attractors relatively evenly, but not enough.

Passenger Rail Transport: Issues of Functioning in Agglomerations of Millionaire Cities

The article is devoted to the study of the existing system of passenger rail transport in cities with a population of one million. Transport infrastructure is an important element of urban infrastructure and participates in the formation of agglomeration links. The article discusses the issue of the connectivity of the outer zone of the city with the agglomeration due to the existing system of using rail transport. Three cities with a population of one million, with similar socio-economic and physical-geographical characteristics - Yekaterinburg, Kazan and Perm, were selected as territorial objects. The similar and different aspects of the formed passenger railway transport systems are revealed. It is concluded that the integral indicator of the level of development of suburban and intracity transport links of external zones demonstrates a strong Perm lag behind Yekaterinburg and Kazan. Yekaterinburg and Kazan possess highly differentiated links between the individual sectors of the city’s outer zone. The “gap” between cities also takes place without taking into account the integration of electric trains with the metro, and becomes even stronger when taking into account the interaction of the two off-street transport systems.

Pre-Alpine Tectono-Stratigraphic Reconstruction of the Jurassic Tethys in the High-Pressure Internal Piedmont Zone (Stura di Viù Valley, Western Alps)

We present a detailed description of the tectono-stratigraphic architecture of the eclogite-facies Internal Piedmont Zone (IPZ) metaophiolite, exposed in the Lanzo Valleys (Western Alps), which represents the remnant of the Jurassic Alpine Tethys. Seafloor spreading and mantle exhumation processes related to the Alpine Tethys evolution strongly conditioned the intra-oceanic depositional setting, which resulted in an articulated physiography and a heterogeneous stratigraphic succession above the exhumed serpentinized mantle. “Complete” and “reduced” successions were recognized, reflecting deposition in morphological or structural lows and highs, respectively. The “complete” succession consists of quartzite, followed by marble and calcschist. The “reduced” succession differs for the unconformable contact of the calcschist directly above mantle rocks, lacking quartzite and gray marble. The serpentinite at the base of this succession is intruded by metagabbro and characterized at its top by ophicalcite horizons. Mafic metabreccia grading to metasandstone mark the transition between the “complete” and “reduced” successions. The character of the reconstructed succession and basin floor physiography of the IPZ metaophiolite is well comparable with the Middle Jurassic–Late Cretaceous succession of both the Queyras Complex (External Piedmont Zone) and the Internal Ligurian Units (Northern Apennines) and with modern slow-spreading mid-ocean ridges.

ارزیابی اثر ورقهای مضاعف بر رفتار برشی و اتکایی اتصال تیر ممتد فولادی و ستون بتن مسلح (RCS)

با گذشت سه دهه مطالعه و تحقیق بر روی قاب‌های مرکب ساخته شده از تیر ممتد فولادی و ستون بتنی (قاب‌های RCS) ثابت شده که این قاب‌ها در نواحی پرخطر لرزه‌ای نیز عملکرد مناسبی از خود نشان می‌دهند. ارائه‌ی چیدمانی مناسب از اجزای اتصال RCS همواره یکی از دغدغه‌های جامعه مهندسی بوده است. پیش‌نویس آیین‌نامه‌ی ASCE 2015 درباره‌ی اتصالات RCS در فهرستی که برای اجزای این اتصال پیشنهاد داده، به ورق مضاعف در جان تیر فولادی اشاره کرده است. این مقاله به بررسی اثر ضخامت ورق مضاعف در جان تیر فولادی، بر روی عملکرد اتصال RCS پرداخته و با استفاده از یک چارچوب مدل‌سازی اجزای محدود که پیش‌تر با نتایج مطالعات آزمایشگاهی صحت‌سنجی شده معایب و مزایای استفاده از هر یک از این ورق‌ها را آشکار می‌سازد. نتایج این بررسی نشان می‌دهد که استفاده از ورق‌های مضاعف، میزان مشارکت مکانیزم‌های مرتبط با چشمه‌های بتنی داخلی و خارجی را در مقاومت اتصال به شکلی چشم‌گیر افزایش می‌دهد.

Factors based on optical coherence tomography correlated with vision impairment in diabetic patients

The aim of this study is to evaluate the relationship between retinal structures and visual acuity in diabetic patients using optical coherence tomography (OCT) and OCT angiography (OCTA). This study was a retrospective observational study conducted at a single medical center in Japan. Evaluation of retinal images was analyzed using spectral domain OCT. Twelve factors including central retinal thickness, length of disorganization of retinal inner layer (DRIL), number of inner hyperreflective foci, number of outer hyperreflective foci, height of intraretinal fluid, height of subretinal fluid, length of external limiting membrane disruption, length of external ellipsoid zone (EZ) disruption, vessel density of superficial capillary plexus (SCP), foveal avascular zone (FAZ) area, and FAZ circularity were analyzed based on OCT/OCTA findings. Multivariate analysis was used to investigate the OCT-based factors that could be correlated with poor visual acuity in treatment-naïve diabetic eyes. A total of 183 eyes of 123 diabetic patients with type 2 diabetes (mean age 61.9 ± 12.3 years, 66 men and 57 women) and 62 eyes of 55 control subjects (mean age 64.4 ± 12.5 years, 15 men and 40 women) was enrolled in this study. Multiple regression analysis showed that OCT-based factors correlated with visual acuity were length of DRIL (β = 0.24, P < 0.01), length of EZ disruption (β = 0.35, P < 0.001), and FAZ circularity (β = − 0.14, P < 0.05). The other factors showed no significant correlation. In conclusion, the length of DRIL, length of EZ disruption, and FAZ circularity measured by OCT were identified as related factors for visual impairment in treatment-naïve diabetic eyes.

Impact of serpentinized peridotite mine waste on the composition and quality of sediments in the Ría de Ortigueira (Galicia, NW Spain)

The Ría de Ortigueira is an environmentally well conserved; however, the sediments show high concentrations of toxic elements. In some zones, the concentrations of Ni (60–1080 mg kg−1) and Cr (9–567 mg kg−1) were extremely high, while the concentrations of other toxic elements were within normal ranges. PCA revealed that metal enrichment was due to dumping of waste sludge from a peridotite mine. The study of marine currents showed that the exit of the contaminated waste towards the external zone is restricted by the low energy of the residual currents, and the sludge therefore remains trapped in the internal zones. The potential ecological risk was moderate for all areas of the ría, reaching high values close to the mouth of the river Landoi. Finally, geochemical fractioning showed that most of the metals are associated with Fe oxyhydroxides which can become unstable and release adsorbed or coprecipitated metals, especially Ni.

Effect of Lateral Crural Procedures on Nasal Wall Stability and Tip Aesthetics in Rhinoplasty.

To evaluate the lateral nasal wall stability, nasal function, and cosmesis when creating an aesthetically pleasing nasal tip subunit utilizing lateral crus (LC) altering procedures. Retrospective cohort. In this retrospective cohort study, cosmetic rhinoplasty patients undergoing LC procedures with available lateral wall insufficiency (LWI) scores were included. An LWI grading system was used to evaluate internal (zone 1) and external (zone 2) nasal valves objectively. Secondarily, Nasal Obstruction Symptom Evaluation (NOSE) Score, Visual Analog Scale (VAS) and Standardized Cosmesis and Health Nasal Outcomes Survey (SCHNOS) results were evaluated. Based on the LC intervention, the cohort was divided into six groups: lateral cural strut graft (LCSG), mini-LCSG, lateral crural overlay (LCO) with and without additional support, cephalic trimming, and cephalic turn-in flaps. Subjects undergoing LCO with and without support, LCSG, and mini-LCSG showed significant improvement in zone 1 LWI (P = .042, P = .041, P < .001, and P < .001, respectively), while cephalic trimming and turn-in/hinged flaps had no effect. Subjects undergoing LCO with support and LCSG showed significant improvement in zone 2 LWI (P = .022, P = .004), while LCO without support, mini-LCSG, cephalic trimming, and turn-in flaps showed no effect on LWI. The SCHNOS-C and VAS-C showed significant improvement in all subgroups (P < .05) when comparing pre- to postoperative values. Alar-spanning sutures did not significantly change zone 1 scores but did conceal zone 2 improvements in LCSG and LCO with support groups. Selected LC procedures are robust techniques for improving tip cosmesis independently without compromising nasal lateral wall stability. Some LC procedures can improve nasal valves patency in tip surgery. Laryngoscope, 131:E1830-E1837, 2021.

Setting-Less Nonunit Protection Method for DC Line Faults in VSC-MTdc Systems

Existing nonunit protection schemes inevitably require setting, which is a serious problem in practical engineering. Faults occurred at different fault zones will result in different equivalent models, therefore, the fault zone can be determined by recognizing which equivalent model the fault fits well with. In this article, this “model recognition” idea is introduced in fault identification and a “setting-less” protection method is proposed. First, the Peterson equivalent circuits when faults occur at backward external zone, internal zone, and forward external zone are presented, respectively. Accordingly, the corresponding three fault voltage expressions are derived, which are defined as three fault modes. Then, the three fault modes are used to approximate the measured fault voltage using Levenberg-Marquardt optimal approximation method. The fault mode that best fits the measured fault voltage is recognized as the final determined fault mode, which is used for fault identification without setting threshold value. Numerous test studies carried out in Power Systems Computer Aided Design/Electromagnetic Transients including DC (PSCAD/EMTDC) and real-time digital simulator have demonstrated that the proposed method can be utilized for different multiterminal dc systems and is effective under different fault locations, different fault types, and high fault impedances. The proposed method does not require high sampling frequency and has good robustness against measuring noise.