scholarly journals Influence of Gamma Irradiation and Water Aging on the Space Charge Characteristics of Epoxy Micro-Nano Composites

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 964
Author(s):  
Myneni Sukesh Babu ◽  
Ramanujam Sarathi ◽  
Takahiro Imai ◽  
Toshikatsu Tanaka
Keyword(s):  
Electric Field ◽  
Gamma Irradiation ◽  
Space Charge ◽  
Ion Trapping ◽  
Polarity Reversal ◽  
Nano Composites ◽  
Nano Composite ◽  
Charge Decay ◽  
The Mean ◽  
The Impact

Epoxy micro-nano composites are well-known to exhibit enhanced electrical, mechanical as well as thermal properties compared to base epoxy resin. Yet, a clear understanding need to be achieved on the long-term aging performance of the epoxy micro-nano composites. The present review article is a comprehensive study on the impact of gamma irradiation and water aging on the space charge characteristics of epoxy micro-nano composites that are applicable as insulant in high-voltage power apparatus. Ion-trapping nanoparticles, which possess good oxidation resistance and high ion trapping ability, are being chosen as nanofillers along with silica micro fillers in epoxy micro-nano composite material for improving the reliability of electrical insulation structures. The epoxy micro-nano composite specimens were subjected to gamma irradiation (4 kGy and 8 kGy) and water aging (under room temperature and at 90 °C), to analyze the effect of aging on space charge accumulation and charge decay characteristics. The mean magnitude of accumulated space charge density of epoxy micro-nano composites tends to increase with an increase in gamma irradiation dose as well as an increment in water diffusion coefficient. The mean lifetime of the space charge decay during depoling has significantly reduced after gamma irradiation and is converse with water aged specimen. Voltage polarity reversal studies have indicated that a part of homo-charge injected from electrodes remained as hetero-charge just after polarity reversal and could result in the distortion of electric field thereby increasing the electric field enhancement factor.

scholarly journals Effect of Temperature on Space Charge Distribution of Oil–Paper Insulation under DC and Polarity Reversal Voltage

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2271 ◽  
Author(s):  
Qingguo Chen ◽  
Jinfeng Zhang ◽  
Minghe Chi ◽  
Peng Tan ◽  
Wenxin Sun
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Electric Field Distribution ◽  
Operating Conditions ◽  
Polarity Reversal ◽  
Effect Of Temperature ◽  
Slow Decay ◽  
Voltage Polarity ◽  
Field Distortion ◽  
Paper Insulation

The electric field distortion caused by space charge is an important factor affecting the operation reliability of oil–paper insulation in a converter transformer. To study the accumulation and decay characteristics of the space charge within oil-impregnated pressboard under DC and polarity reversal voltage, and consider the possible operating conditions of the converter transformer, the space charge behavior of oil-impregnated pressboard was measured by the pulsed electro-acoustic (PEA) method in the temperature range from −20 °C to 60 °C. The effect of temperature on the accumulation and decay characteristics of space charge is also analyzed. The space charge accumulated within the pressboard at low temperature is mainly homocharge injected by the electrode, while heterocharge formed by ion dissociation counteracts some of the homocharge at high temperature. Thus, the space charge of pressboard first increases, then decreases, with an increase in temperature. However, slow decay of the space charge causes severe distortion of the electric field distribution in the pressboard during voltage polarity reversal.

scholarly journals Numerical Analysis of Space Charge Behavior and Transient Electric Field under Polarity Reversal of HVDC Extruded Cable

Energies ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2845
Author(s):  
Sun-Jin Kim ◽  
Bang-Wook Lee
Keyword(s):  
Steady State ◽  
Electric Field ◽  
Space Charge ◽  
Field Intensity ◽  
Electric Potential ◽  
Electric Field Intensity ◽  
Dielectric Breakdown ◽  
Operating Conditions ◽  
Polarity Reversal ◽  
Transient Electric Field

The superimposed transient electric field generated by polarity reversal causes severe stress to the high-voltage direct current (HVDC) cable insulation. Especially for polymeric insulation materials, space charge accumulation is prominent, which strengthens local electric field intensity. In order to avoid the risk of dielectric breakdown resulting from an intensified electric field caused by space charge behavior, several numerical analyses have been conducted using the Bipolar Charge Transport (BCT) model. However, these studies have only considered a unidirectional electric field assuming only steady state operating conditions, and there are few works that have analyzed space charge behavior during transient states, especially for the polarity reversal period. In order to analyze the charge behavior under polarity reversal, it is necessary to establish the boundary condition considering the direction and intensity of the field. Therefore, in this paper, we proposed a modified model connecting the steady state to the polarity reversal state, and the transient electric field was investigated depending on the electric potential zero duration. Since space charge behavior is influenced by temperature, different load currents were considered. From the simulation results, it was observed that the capacitive field was dominant on the electric field distribution during the polarity reversal. In addition, the long electric potential zero duration and high load currents could contribute to form a homo-charge at the conductor within the time of polarity reversal, resulting in a noticeable decrease in the maximum electric field intensity.

Routine Use of Platelet Components Prepared with Photochemical Treatment (INTERCEPT Platelets) : Impact on Clinical Outcomes and Costs.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3629-3629 ◽  
Author(s):  
Jean Claude Osselaer ◽  
Chantal Doyen ◽  
Anne Sonet ◽  
Maryse Van Hooydonk ◽  
Edith Goossenaerts ◽  
...  
Keyword(s):  
Gamma Irradiation ◽  
Average Dose ◽  
Before And After ◽  
Integrated Processing ◽  
Component C ◽  
The Mean ◽  
The Cost ◽  
The Impact ◽  
Care Costs ◽  
Donor Recruitment

Abstract Background: In 2003 the Blood Transfusion Ctr (BTC), Cliniques Universitaires Mont Godinne (CU-MG) initiated routine use of INTERCEPT Platelets (I-P) for transfusion support of thrombocytopenia. To examine the impact of I-P on patient outcomes and costs, the rate of acute transfusion reactions (ATR) for platelet (PLT) and red cell (RBC) transfusions (txn) were compared for 285 days (d) before I-P adoption, when only conventional platelets (C-P) were used, and for 255 d after adoption of I-P for routine use. Since preparation of RBC did not change, the relative rates of PLT-ATR and RBC-ATR in the 2 periods were used to assess the impact of I-P on ATR. Methods: In both periods, PLT were collected on the Amicus Cell Separator (Baxter) with process leuko-reduction. For C-P, T-Sol (Baxter) with a ratio to plasma of ~ 70:30 % was used; and for I-P, Intersol (Baxter)with a ratio to plasma of ~ 65:35 % was used. I-P containing 2.5 to 6.0 x 1011 plts in ~ 300 mL were prepared with an integrated processing set using amotosalen (S-59, 150 uM) and UVA (3 J/cm2) to inactivate pathogens and leukocytes. As for C-P, I-P were issued the d after collection and were stored for up to 5 d. The Hematology Service reported PLT and RBC ATR (febrile and non-febrile ATR occurring within 24 hr of txn) to the BTC. HLA and PLT antibodies (AB+/AB−) were determined by the BTC in pts with suspected alloimmunization. Factors impacting costs for PLT, before and after adoption of I-P, were assessed by the BTC. Results: Days of observation before and after adoption of I-P were similar (Table). More pts received I-P, due to an increase of CV surgery pts after I-P adoption. The mean plt dose was 2% lower with I-P (4.06 vs 4.15 x 1011), and the number of PLT txn/pt was 8% higher for I-P. The rate of ATR to PLT txn with I-P showed a declining trend (p =0.08) , while the rate of ATR to RBC txn was similar in the 2 periods (p = 0.55). Before and after I-P, 16.5 and 9.3 % of pts receiving plt had PLT ATR, respectively. The decrease was largely due to fewer ATR in pts without AB detected (AB-). Adoption of I-P did not require addition of personnel to the BTC, nor delay time of PLT issue. I-P did not affect the number of plt donors required to support the CU-MG patient population. I-P replaced gamma irradiation for prevention of txn-associated GVHD and avoided use of routine bacterial testing for PLT. Conclusions: Use of I-P resulted in a trend of decreased incidence for ATR to PLT txn on a per txn and per pt basis compared to RBC ATR. The average dose of I-P was minimally lower than C-P, and the number of PLT txn/pt was slightly increased. Adoption of I-P did not adversely impact the cost of donor recruitment or donor utilization nor the cost of BTC personnel. I-P avoided the cost of gamma irradiation and routine bacterial cultures. I-P offer the potential to reduce patient care costs due to reduced ATR. Impact of I-P Adoption Component C-P C-RBC I-P C-RBC Period Before Before After After na = not available Days 285 285 255 255 Patients 103 na 129 na Hem-Onc 47% na 44% na CV Surgery 35% na 47% na TXN (units) 1466 5110 1990 4895 ATR : No. TXN (%) 23 (1.57%) 18 (0.35%) 18 (0.90%) 21 (0.42%) AB+/AB- 6/13 3/15 6/7 4/17 TXN/Patient 14.2 na 15.4 na

Electric Field Analysis with Space Charge Effects of ±1000kV DC Wall Bushing

2014 ◽  
Vol 1008-1009 ◽  
pp. 598-602
Author(s):  
Shu Min Sun ◽  
Yan Cheng ◽  
Xin Su
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Field Distribution ◽  
Electric Field Distribution ◽  
Element Model ◽  
Field Analysis ◽  
Polarity Reversal ◽  
Space Charge Effects ◽  
Charge Effects ◽  
Electric Field Analysis

±1000kV DC wall bushing is a complex insulation system working in different conditions, such as DC, AC and polarity reversal. No matter what kind of conditions, the space charge effects on the electric field distribution of the bushing are remarkable. A finite element model for ±1000kV DC wall bushing is established based on space charge theory, to analyze the electric field distribution in different conditions, especially when polarity reversal occurs. The research results provide useful references for the electric field analysis and insulation optimization of UHV (ultra high voltage) DC wall bushings.

scholarly journals The Impact of Cross-Linking Effect on the Space Charge Characteristics of Cross-Linked Polyethylene with Different Degrees of Cross-Linking under Strong Direct Current Electric Field

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1149 ◽  
Author(s):  
Shuchao Wang ◽  
Quan Zhou ◽  
Ruijin Liao ◽  
Lai Xing ◽  
Nengcheng Wu ◽  
...  
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Space Charge ◽  
Direct Current ◽  
Cross Linking ◽  
Average Charge ◽  
Electrical Field ◽  
Electrical Field Strength ◽  
The Cross ◽  
The Impact

Cross-linked polyethylene (XLPE) obtained by the crossing-linking reaction of polyethylene (PE) can greatly enhance the mechanical properties and other properties of PE, which makes XLPE widely applied in the field of electric power engineering. However, the space charges can distort the distribution of the electrical field strength in the XLPE applied in the insulation materials, which can shorten the service life of the insulation materials. Therefore, the space charge characteristics of XLPE under the strong direct current (DC) electric field have been the focus of scholars and engineers all over the world. This article has studied the impact of the cross-linking effect on the space charge characteristics of XLPE with different degrees of cross-linking. For this issue, we used dicumyl peroxide (DCP) as the cross-linking agent and low-density polyethylene (LDPE) as the base material for the preparation of samples. Besides, the space charge distribution was measured by the pulsed electro-acoustic method (PEA). In addition, the average charge density as a characteristic parameter was introduced into the experiment, which was used to quantitatively analyze the impact of the cross-linking effect on the space charge characteristics of XLPE with different degrees of cross-linking. Meanwhile, we also explained the impact of the cross-linking effect on XLPE with different degrees of cross-linking from a microscopic point of view. Ultimately, some important conclusions can be obtained. For instance, the cross-linking effect significantly increases the threshold electrical field strength of XLPE, and as the content of cross-linking agent increases, the threshold electrical field strength increases at first and then decreases, and the threshold electrical field strength reaches the maximum value when the content of the cross-linking agent is 1.0% or 2.1%. Besides, the cross-linking effect introduces negative charge traps into the LDPE and increases the densities of the deeper charge traps, and so on. In addition, we have also analyzed the average charge density, and we have summarized the theoretical model of the average charge decay, namely, Q ( t ) = Q 0 + α e − t β , which is very effective for explaining the dissipation characteristics (more conclusive contents can be seen in the conclusion section of this article).

scholarly journals The Effect of Pre-Storage Irradiation Blood on Quality of Red Blood Cells

2021 ◽  
Author(s):  
Nahal Eshghifar ◽  
Mahtab Maghsudlu ◽  
Sedigheh Amini KafiAbad
Keyword(s):  
Gamma Irradiation ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Plasma Potassium ◽  
Plasma Sodium ◽  
Blood Collection ◽  
Mean Values ◽  
The Mean ◽  
The Impact ◽  
2,3 Dpg

Background: Irradiation leads to increased storage lesions that may have harmful effects if transfused. Various storage lesions research has been carried out, and only very few articles are available on the impact of gamma irradiation on RBC storage lesions. Since there has been no study about finding the best time for irradiation, we decided to investigate the effect of irradiation on Red blood cells at different storage times after blood collection Materials and Methods: A total of 40 units of red blood cells divided into two groups, irradiated and nonirradiated. Irradiated RBCs were divided into three groups and each group containing ten units. The remaining ten units were considered as non-irradiated controls. Sampling from these irradiated and non-irradiated blood units was performed weekly to evaluate biochemical parameters and free plasma hemoglobin/Hemolysis index levels. Results: A significant increase in the mean values of plasma potassium, plasma Hb/Hemolysis index, and LDH, as well as a significant reduction in the mean value of 2,3 DPG and plasma sodium, were observed in both groups. Although the reduction of 2,3 DPG is extremely remarkable, it is compensated 24-48 hours after transfusion. Hence, the clinical result of 2,3-DPG-depleted RBC transfusion is known to be negligible. The irradiation group alteration was more notable than the non-irradiated one and the changes in the parameters were most significant in the group having been stored for a longer period after irradiation. Conclusion: Our investigation on the impact of gamma irradiation on RBCs makes it possible to suggest a storage time up to 28 days after irradiation is permissible and the best time for irradiation after blood collection is up to 14 days. It is pointed out that the blood unit should be transfused as soon as possible after the irradiation.

scholarly journals Space Charge Characteristic of Nano-composite Film of MgO/LDPE under DC Electric Field

2006 ◽  
Vol 126 (11) ◽  
pp. 1078-1083 ◽  
Author(s):  
Yoshinobu Murakami ◽  
Masanori Nemoto ◽  
Rudi Kurnianto ◽  
Naohiro Hozumi ◽  
Masayuki Nagao ◽  
...  
Keyword(s):  
Electric Field ◽  
Composite Film ◽  
Space Charge ◽  
Nano Composite ◽  
Charge Characteristic ◽  
Dc Electric Field

Asteroid and Comet Impact Speeds upon Mars: Significance for Panspermia and the Supply of Organics

1997 ◽  
Vol 161 ◽  
pp. 197-201 ◽  
Author(s):  
Duncan Steel
Keyword(s):  
Probability Distributions ◽  
Regions Of Interest ◽  
Significant Fraction ◽  
Organic Chemicals ◽  
Impact Speed ◽  
The Mean ◽  
The Impact

AbstractWhilst lithopanspermia depends upon massive impacts occurring at a speed above some limit, the intact delivery of organic chemicals or other volatiles to a planet requires the impact speed to be below some other limit such that a significant fraction of that material escapes destruction. Thus the two opposite ends of the impact speed distributions are the regions of interest in the bioastronomical context, whereas much modelling work on impacts delivers, or makes use of, only the mean speed. Here the probability distributions of impact speeds upon Mars are calculated for (i) the orbital distribution of known asteroids; and (ii) the expected distribution of near-parabolic cometary orbits. It is found that cometary impacts are far more likely to eject rocks from Mars (over 99 percent of the cometary impacts are at speeds above 20 km/sec, but at most 5 percent of the asteroidal impacts); paradoxically, the objects impacting at speeds low enough to make organic/volatile survival possible (the asteroids) are those which are depleted in such species.

Sign in / Sign up

Export Citation Format

Share Document