Neutral Resistance Research Articles

Sequence variations of the MHC class I gene exon 2 and exon 3 between infected and uninfected chickens challenged with Marek’s disease virus

The major histocompatibility complex (MHC) among chickens has been well established as being associated with disease resistance and pathogens infection, but the genetic differences in MHC between chickens susceptible to certain infections and those chickens that remain uninfected have not been sufficiently determined. In this study, we sought the genetic basis that may underlie differences in susceptibility to infection among chickens by challenging four groups of broilers with Marek’s disease virus (MDV). Over the course of the experiment, lesions began to appear between 21 and 35days post challenge (dpc), and commercial broilers were not necessarily better than indigenous chickens in terms of disease resistance. The four groups showed neutral resistance to MDV infection validated by challenge results and evolutionary analysis of exons 2 and 3 of the MHC class I region. Several variable sites in exon 2 and exon 3 were exclusively appeared in infected chickens. Exon 3 was likely more crucial than exon 2 in disease resistance. Our observations offered a support for a potential association between promiscuous pathogens and conspicuous genetic diversity in the MHC class I region.

Pumps: The Heart of Any Cleaning Machine

Corrosion resistance of anodized aluminum sealed with conventional and a new sealant was tested against the alkaline, acid and neutral chloride salt solutions. The results show that the conventional water based sealants have good acid and Neutral Salt Fog resistance; however, they do not possess the necessary alkaline corrosion resistance to be used for decorative and automotive exterior applications. A new anodic coating sealant was developed to provide the necessary alkaline corrosion resistance along with the acid and neutral salt attack resistance. Acid Dissolution Test (ADT) Rating, Alkaline Corrosion Resistance, Neutral Salt Fog, Heat Resistance and Alkaline Car Wash Detergent tests were done in accordance with General Motors Spec GMW 14665. Results revealed that this novel sealant is significantly capable of meeting the rigorous GMW 14665 specification and can be used for sealing the anodic coatings used in automotive exterior applications.

Alkaline Corrosion-Resistant Sealant for Anodized Aluminum Alloys

Corrosion resistance of anodized aluminum sealed with conventional and a new sealant was tested against the alkaline, acid and neutral chloride salt solutions. The results show that the conventional water based sealants have good acid and Neutral Salt Fog resistance; however, they do not possess the necessary alkaline corrosion resistance to be used for decorative and automotive exterior applications. A new anodic coating sealant was developed to provide the necessary alkaline corrosion resistance along with the acid and neutral salt attack resistance. Acid Dissolution Test (ADT) Rating, Alkaline Corrosion Resistance, Neutral Salt Fog, Heat Resistance and Alkaline Car Wash Detergent tests were done in accordance with General Motors Spec GMW 14665. Results revealed that this novel sealant is significantly capable of meeting the rigorous GMW 14665 specification and can be used for sealing the anodic coatings used in automotive exterior applications.

Simulation and Analysis of the Neutral Resistance Grounding of 1140V Power System in Coal Mine

The neutral grounding mode through resistance and the grounding resistance value of 1140V coal mining distribution system are studied and simulated in this paper. According to the 1140V power supply system parameter of the underground mining area of a coal mine, the PACAD software is used to establish the simulation model of power system. The single-phase ground fault caused by the insulation deterioration of the load equipment is simulated through setting single-phase ground fault in charge line of load side. The advantage of neutral grounding mode through resistance is analyzed through the simulation result. According to the distributed capacitance over the ground of simulation data and power network, the value range of the neutral point grounding resistance can be obtained.

Plating Hard Chrome Plating Alternative Technologies - HVOF Tungsten Carbide Coating

HOVF technology preparation of tungsten carbide coating, can be obtained the microhardness and neutral salt spray corrosion resistance superior to the protective layer of hard chrome plating, its own good toughness and high bonding strength of the matrix, itideal replacement for hard chrome plating technology

The Effect of Physicochemical Surface Treatment Methods on Bond Strength of Zirconia to Resin Cement: A Review of the Literature

Objective: Zirconium oxide has gained the spotlight during the recent years as a high strength ceramic material. However, despite its mechanical superiorities, it forms a weak bond with different synthetic substrates and tissues due to its neutral nature and resistance against chemical agents. Therefore, it is important to improve the bonding technique in order to prevent microleakage and increase retention and fracture resistance of the restoration. Literature Review: Since the discovery of zirconium oxide, several surface treatment methods have been evaluated to increase its bond strength to resin cement such as surface grinding with micro- abrasion, burs or abrasive papers, tribochemical silica coating, silicoating, glass micropearls, glaze- on technique, selective infiltration etching, hot etching and use of phosphate ester monomers. The mentioned techniques and related articles are reviewed and discussed in the present study. Conclusion: Despite extensive studies, no consensus has been reached about a specific treatment as the standard protocol for improving the bond strength of zirconia restorations.

A generalized dynamical model for transformers with saturation and hysteresis effects

This article presents a new generalized non-linear dynamical model of a transformer with saturation and hysteresis effects. The structure of this new model is based on a magnetic equivalent circuit with non-linear reluctance elements. Using this method, accurate models of three- and five-legged transformers with magnetic saturation and hysteresis phenomena of iron core are introduced and inrush current in normal and sequential phase energization techniques are evaluated. Moreover, the effects of neutral resistance, magnetic structure and winding connections on inrush current are determined. In addition, for validation of the proposed model, some numerical simulations are made and compared with other techniques. Simulation results illustrate that the proposed model has high accuracy and efficiency for non-linear dynamical modelling of a transformer.

Ferroresonance Elimination in 275kV Substation

This work studies the non-conventional ferroresonance oscillation in the 275kV substation. Voltage transformer (VT) which is used in this substation has a 100VA capacity and magnetization characteristic of it was modeled by single-value two-term polynomial with q=7. In this study, at first ferroresonance oscillation in VT has been introduced, then effect of Metal Oxide Varistor (MOV) on limiting these nonlinear overvoltages is investigated. It has been shown for some parameters values, MOV cannot control the ferroresonance. So, by connecting the neutral earth resistance (NR) to the system grounding, non-conventional oscillation has been controlled for all value of system parameters. Simulation results show that considering neutral earth resistance exhibit great controlling of ferroresonance overvoltages. It is also shows by using this resistance, system exhibit less sensitivity to the changing the parameters value of the power system.

Analyzing Ferroresonance Phenomena in Power Transformers Including Zinc Oxide Arrester and Neutral Resistance Effect

This paper studies the effect of zinc oxide arrester (ZnO) and neutral earth resistance on controlling nonconventional oscillations of the unloaded power transformer. At first, ferroresonance overvoltage in the power system including ZnO is investigated. It is shown this nonlinear resistance can limit the ferroresonance oscillations but it cannot successfully control these phenomena. Because of the temperature dissipation of ZnO, it can withstand against overvoltage in a short period and after that ferroresonance causes ZnO failure. By applying neutral earth resistance to the system configuration, mitigating ferroresonance has been increased and chaotic overvoltage has been changed to the smoother behavior such as fundamental resonance and periodic oscillation. The simulation results show that connecting the neutral resistance exhibits a great mitigating effect on nonlinear overvoltage.

Nonlinear Oscillation in Potential Transformers Connected Controlling Circuit

In this work at first ferroresonance phenomenon is introduced and then various type of ferroresonance overvoltages in a potential transformer is simulated. Then effect of neutral earth resistance on controlling these oscillations in the case of nonlinear core losses has been studied. Core losses in the potential transformer are modelled by third order power series in terms of voltage and include nonlinearities in core losses. It is expected that neutral earth resistance generally can cause ferroresonance 'dropout'. For confirmation this aspect Simulation has been done on a one phase potential transformer rated 100VA, 275kV. The simulation results show that connecting the neutral earth resistance on the system configuration, shows a great controlling effect on ferroresonance oscillation.

Damping Nonlinear Oscillations in Potential Transformers Including Hysteresis Effect

In this work, an overview of available papers are provided, at first ferroresonance phenomenon is introduced and then various type of ferroresonance in a potential transformer is simulated, then effect of neutral earth resistance on the onset of chaotic ferroresonance and duration of chaotic transient in a potential transformer including nonlinear core losses has been studied. It is expected that this resistance generally cause controlling ferroresonance overvoltages. The proposed approach was implemented using MATLAB, and results are presented. For confirmation this aspect simulation has been done on a one phase potential transformer rated 100VA, 275kV. Core losses is modelled in terms of voltage and includes nonlinearities in core losses .The simulation results show that connecting the neutral earth resistance on the system configuration, shows a great controlling effect on ferroresonance overvoltages.

Controlling Chaotic Ferroresonance in Autotransformer connecting Metal Oxide Surge Arrester and Neutral Earth Resistance

This paper investigates the effect of linear core losses, metal oxide surge arrester (MOSA) and neutral earth resistance on the onset of chaotic ferroresonance and controlling these overvoltages in an autotransformer. The transformer is chosen for study has a rating of 50 MVA, 635.1 kV. The magnetization characteristic of the autotransformer is modeled by a nonlinear polynomial. The core loss is modeled by linear core losses and is shown as a linear resistance. Three state of ferroresonance are studied: (i) onset of chaos due to interrupt in switching action including linear core losses of the transformer, (ii) effect of MOSA on the limiting these oscillation, and (iii) completely controlling effect of neutral earth resistance on the ferroresonance overvoltages. Results of simulation have been derived and shown by nonlinear dynamics method such as bifurcation diagrams, phase plan and time domain simulations.

Experimental Research of the Overvoltage in the Insulated Neutral Network

Experimental Research of the Overvoltage in the Insulated Neutral Network The isolated neutral network isolation resistance is often affected by the lightning discharge surge to the line cables or towers. Several overvoltage waves are maid at the moment of the lightning discharge surge. It is dangerous for the devices because at the very short time period the isolation of the device is affected by the surge impact twice or even more. The analysis of the experimentally registered lightning discharge induced overvoltage transients effect from the lightning influence to the power line till the power line disconnection were analyzed in this work. Estimation of the overvoltage characteristics to the isolation resistance was made.

Testing of a Wavelet-Packet-Transform-Based Differential Protection for Resistance-Grounded Three-Phase Transformers

This paper presents an extension of real-time tests of a wavelet-packet-transform-based technique for the differential protection of three-phase power transformers. The proposed technique is implemented using a DS1102 digital signal processor board and tested on two different three-phase power transformers with neutral resistance grounded. Different magnetizing inrush and internal fault currents are investigated with current transformer (CT) saturation for different loading conditions, including capacitive loads. The results show a complete independence from transformer parameters, load types, grounding method, or CT saturation. Furthermore, the proposed technique has high speed, good accuracy, small required memory, and reliable responses with reduced computational burden. In all cases of the investigated internal faults, the proposed algorithm is capable of identifying the fault and generating a trip signal in less than a quarter cycle based on a 60-Hz system.

Effect of Neutral Path Power Losses on the Apparent Power Definitions: A Preliminary Study

This paper presents the theoretical background needed to understand the effect of the parameters that affect the ratio rho between the equivalent neutral path resistance and line resistance of a transposed three-phase line. The ratio rho has a significant impact on the value of the apparent power as defined in IEEE Std. 1459. The ratio rho, however, depends on the topology of the power network as well as the type and size of the loads supplied by the feeder on which the apparent power is measured. It was found that for a wide range of conditions rho ap R 0/R +, where R 0, R + are the zero- and positive-sequence resistances of the line supplying the observed load.

Study on nano-CaCO 3 modified epoxy powder coatings

Powder coatings are widely used for their environmental and economical advantages. In this work nano-CaCO 3 modified powder coatings were prepared using epoxy resin/nano-CaCO 3 composites obtained through in situ and inclusion polymerization and the nano-CaCO 3 can be well dispersed in the resultant coatings by this preparation method. Their tensile property, cupping property and neutral salt spray corrosion resistance were distinctly improved. The mechanism of property improvement was discussed.

The importance of the neutral region resistance for the calculation of the interface state in Pb/p-Si Schottky contacts

We have fabricated H-terminated Pb/p-type Si Schottky contacts with and without the native oxide layer to explain the importance of the fact that the neutral region resistance value is considered in calculating the interface state density distribution from the nonideal forward bias current–voltage (I–V) characteristics. The diodes with the native oxide layer (metal–insulating layer–semiconductor (MIS)) showed nonideal I–V behavior with an ideality factor value of 1.310 and the barrier height value of 0.746eV. An ideality factor value of 1.065 and a barrier height value of 0.743eV were obtained for the diodes without the native oxide layer (MS). At the same energy position near the top of the valance band, the calculated interface states density (Nss) values, obtained without taking into account the series resistance of the devices (i.e. without subtracting the voltage drop across the series resistance from the applied voltage values V) is almost one order of magnitude larger than Nss values obtained by taking into account the series resistance.

Relation of ANP and BNP to their N-terminal fragments in fetal circulation: evidence for enhanced neutral endopeptidase activity and resistance of BNP to neutral endopeptidase in the fetus.

To investigate the role of neutral endopeptidase in the turnover of atrial (ANP) and brain (BNP) natriuretic peptides and their N-terminal fragments in human fetal circulation. Retrospective case-control study. Department of Obstetrics and Gynaecology, University of Leipzig, Germany. Nine control pregnancies and nine pregnancies with rhesus isoimmunisation before and after intravascular transfusion. Natriuretic peptides and N-terminal fragments in maternal and fetal blood were measured by radio-immunoassay. Neutral endopeptidase activity was determined by HPLC. Maternal and fetal plasma concentrations of ANP, NT-proANP, BNP, NT-proBNP as well as neutral endopeptidase activity. Ratios between mature peptide and N-terminal fragment. Feto-maternal ratio. Plasma NT-proANP concentrations are 11.7 times higher in fetal than in maternal circulation. The ANP concentration is only 1.8 times higher, probably due to doubled neutral endopeptidase activity. In contrast, both NT-proBNP and BNP are doubled in fetal plasma. Fetuses with Rh isoimmunisation had significantly higher NT-proBNP but not NT-proANP and neutral endopeptidase activity than controls. An additional volume load by intravascular transfusion did not influence N-terminal fragments or neutral endopeptidase activity. Our study is the first to determine NT-pro natriuretic peptide concentrations and neutral endopeptidase activity in human fetuses. The results show that increased fetal neutral endopeptidase activity shifts the ANP/NT-proANP but not the BNP/NT-proBNP ratio and that the shifted BNP/NT-proBNP ratio in fetuses with Rh isoimmunisation does not involve increased neutral endopeptidase activity. These findings point to a BNP degradation that is not dependent on neutral endopeptidase.

Diet and diet preferences of introduced ungulates (Order: Artiodactyla) in New Zealand

Understanding the diet and diet preferences of introduced ungulates is a crucial step towards modelling their trophic interactions and managing their impacts. We collated information on the diet of 8 introduced ungulates (Order: Artiodactyla) from 19 studies in New Zealand. A total of 185 indigenous plant genera (379 species) was recorded as eaten. Five studies assessed diet choice by 4 ungulate species (red deer, fallow deer, white‐tailed deer, and feral goats) in forests. Of the 60 plant species or genera present in two or more studies, 8 were always “preferred” (eaten more than expected from their availability) and 15 were always “avoided” (proportionately less eaten than was available); most others were “not selected” (eaten in proportion to their availability). From these data we constructed a table of preferences for commonly occurring forest plant species. Ungulates preferred woody species with low foliar lignin. Although there was no significant relationship between diet choice and foliar N, avoided species all had low foliar N. Ungulate preferences for fern species were closely related to foliar P concentrations, but not to foliar N concentrations. Since relatively few plant species were consistently preferred, we conclude that many native species have neutral resistance to ungulate herbivory, a conclusion that is contrary to the notion that the New Zealand flora is especially vulnerable to introduced herbivores.

Characterisation of aluminium alloys after HNO3/HF–NaOH–HNO3/HF pretreatment

The effect of a pretreatment sequence on several aluminium alloys was examined by X-ray photoelectron spectroscopy and SEM. The pretreatment consisted of vapour degreasing followed by a three step sequence comprising 1 min immersions in (a) nitric acid–hydrofluoric acid solution, (b) sodium hydroxide solution and (c) a 1 or 5 min immersion in nitric acid–hydrofluoric acid as in step (a). Following each pretreatment step the alloy panels were rinsed in tap water for 1 min. The surfaces of aluminium alloys 2024-T3, 6061-T6, and 7075-T6 were examined at each stage in the pretreatment process. The neutral salt spray resistance of specimens deoxidised with this pretreatment and chromate conversion coated were compared to those deoxidised with a conventional chromate based deoxidiser before conversion coating.