Loss Of Insulation Research Articles

Electrolytes with Controlled Polysulfide Insolvability for Lithium-Sulfur Batteries

With the rise in manufacturing and commercialization of electric vehicles and home-scale integrated battery systems, low cost and high energy batteries are imperative for meeting the demand of the near-future energy requirements. Lithium-sulfur (Li-S) battery is widely known as a promising candidate for next-generation batteries due to its high theoretical specific energy (2600 Wh kg-1), abundance in material, and potentially low cost. However, there are many challenges unique to Li-S battery chemistries that impede the practical implementation of Li-S batteries. The foremost known challenge is inhibiting the shuttling effect of polysulfide (PS) species, Li2Sn (2 < n ≤ 8) that occurs during the discharge of the elemental S and the charge of the discharged product Li2S on the S cathode. The formed PS species can migrate from the S cathode to the Li metal anode and react with the Li resulting in loss of active materials and insulation of Li anode, and consequently reduced battery performance and cycle life. Managing the mechanism of PS formation and dissolution is paramount to developing a sustainable Li-S battery. Electrolyte formulation is a key strategy in overcoming the hurdles of Li-S batteries and controlling the degree of PS dissolution. Ether-based electrolytes are promising candidates due to their well-known compatibility with Li metal and their varying degrees of PS solvation and dissolution. This work focuses on designing electrolytes that optimizes the degree of PS dissolution and improving electrode-electrolyte compatibility with the elemental S cathode and the Li metal anode to enhance the cell stability and enable long-term cyclability. A series of electrolytes that have a more controlled degree of PS formation and solvability are developed to improve compatibility of the Li-S battery and enable superior cyclability.

Study of Insulation Loss in Boiler

Thermal is the main source for power generation in India. The percentage of thermal power generation as compare to other sources is 65%. The main objective of thermal power plant is to fulfill the energy demands of the market and to achieve these demands; plant requires technical availability with the parts reliability and maintenance strategy. This paper deals with the determination of current operating efficiency of Boiler and calculates major losses for Super thermal power plant (India) of 210MW units. Then identify the causes of performance degradation. Also find the major causes of heat losses by Fault Tree Analysis (FTA) and recommends its appropriate strategy to reduce major losses. The aim of performance monitoring is continuous evaluation of degradation i.e. decrease in performance of the steam boiler. These data enable additional information which is helpful in problem identification, improvement of boiler performance and making economic decisions about maintenance schedule.

Abstract PR-008: Modeling epigenetic lesions that cause gliomas

Abstract PR-008: Modeling epigenetic lesions that cause gliomas

Study of brittle fracture and temperature resistance in the range of 20-11000С of autoclaved cellular reinforced materials

In this paper, the study of cellular autoclaved reinforced material resistant to brittle fracture and temperatures in the range of 20-1100С. The analysis of the results shows that the studied cellular autoclaved reinforced materials by the value of F (brittle fracture criterion) will not brittle fracture under conditions of a sharp change in temperature from 20 to 300 °C because the value of F ≤ 4. It was determined that on the wall system made of blocks of the material in question with a density of 400 kg/m3, 10 days after the completion of masonry under standardized fire exposure for 180 minutes in the temperature range of 20-1100 °C, there was no loss of thermal insulation, bearing capacity and integrity of the samples. During the tests, the maximum temperature values in the middle of the cross-section of the samples did not exceed 97°C. The values of As, Af, Amin for the test time of 182 minutes were 175074, 175212, 168560 Сmin, respectively, which meets the criterion requirements of DSTU B V.1.1-19:2007 and ensures the fire resistance class REI 180.

Effect of temperature and Humidity on the Thermal Conductivity λ of Insulation Materials

The aim of this article is to address the influence of air humidity and testing temperature on the thermal conductivity coefficient (λ) of various thermal insulation materials. This group includes wood-based materials, rock wools, heat-insulating renders, climate boards, and lightweight cellular concretes. These materials are used both indoors and outdoors in buildings. Over the course of several years, data were collected from laboratory tests to determine the thermal conductivity coefficient (λ) in relation to increases in temperature and humidity. The obtained results were compared with values provided by the manufacturers of the insulation materials. The aforementioned research was carried out due to the rather high sorption of most materials and thus the possibility of them becoming humid at high air humidity. Because of the very large difference in the thermal conductivity coefficient of water and air, a relatively small increase in the mass moisture content of the materials results in a loss of insulation.

The potential of epigenetic therapy to target the 3D epigenome in endocrine-resistant breast cancer

Three-dimensional (3D) epigenome remodeling is an important mechanism of gene deregulation in cancer. However, its potential as a target to counteract therapy resistance remains largely unaddressed. Here, we show that epigenetic therapy with decitabine (5-Aza-mC) suppresses tumor growth in xenograft models of pre-clinical metastatic estrogen receptor positive (ER+) breast tumor. Decitabine-induced genome-wide DNA hypomethylation results in large-scale 3D epigenome deregulation, including de-compaction of higher-order chromatin structure and loss of boundary insulation of topologically associated domains. Significant DNA hypomethylation associates with ectopic activation of ER-enhancers, gain in ER binding, creation of new 3D enhancer–promoter interactions and concordant up-regulation of ER-mediated transcription pathways. Importantly, long-term withdrawal of epigenetic therapy partially restores methylation at ER-enhancer elements, resulting in a loss of ectopic 3D enhancer–promoter interactions and associated gene repression. Our study illustrates the potential of epigenetic therapy to target ER+ endocrine-resistant breast cancer by DNA methylation-dependent rewiring of 3D chromatin interactions, which are associated with the suppression of tumor growth.

Abstract 15424: Phase-to-Phase Short Phenomenon in a Left Ventricular Assist Device: Navigating Through Clinical and Ethical Challenges

Description of Case A 59-year-old male with an axial continuous-flow left ventricular assist device (CF-LVAD) presented asymptomatically after noticing low-flow alarms. He reported extensive external driveline damage that accumulated over one year. The CF-LVAD was connected to an ungrounded cable and the driveline was repaired by the manufacturer. However, low-flow alarms continued. Log files revealed pump stoppages on all modes of power which was compatible with phase-to-phase short phenomenon (PtPSP). The patient was cannulated in case of emergent need for ECMO and upgraded to UNOS status 1 for heart transplant. Because PtPSP was considered unrepairable, the patient underwent emergent cardiac transplantation. Discussion The CF-LVAD driveline consists of three phases, each of which is formed by two electrical wires, connected to six motor stators. PtPSP causes driveline dysfunction due to a loss of insulation between the three phases owing to multiple breaches of the insulator, causing the pump to lose power when the damaged phases come into contact. Pump stoppages are likely and unpredictable even on batteries or an ungrounded cable. Patients may notice alarms associated with low flow, pump speed drops, or pump arrest. PtPSP is unrepairable, and pump exchange or urgent heart transplantation are the only viable treatment options.This case highlights the ethical complexity of the care of patients with advanced heart failure, whereby subjective treatment decisions often translate to objectively different levels of priority on the heart transplantation waiting list without intrinsic measures of disease severity, which may incentivize more aggressive care. Conclusions: CF-LVAD driveline dysfunction due to PtPSP is a clinically asymptomatic ominous scenario often uncovered by pump-controller alarms. Given the high risk of abrupt pump stoppage, a diagnosis of PtPSP necessitates emergent device exchange or explant with an orthotopic heart transplantation.

Lineage specific 3D genome structure in the adult human brain and neurodevelopmental changes in the chromatin interactome.

The human brain is a complex organ comprised of distinct cell types, and the contribution of the 3D genome to lineage specific gene expression remains poorly understood. To decipher cell type specific genome architecture, and characterize fine scale changes in the chromatin interactome across neural development, we compared the 3D genome of the human fetal cortical plate to that of neurons and glia isolated from the adult prefrontal cortex. We found that neurons have weaker genome compartmentalization compared to glia, but stronger TADs, which emerge during fetal development. Furthermore, relative to glia, the neuronal genome shifts more strongly towards repressive compartments. Neurons have differential TAD boundaries that are proximal to active promoters involved in neurodevelopmental processes. CRISPRi on CNTNAP2 in hIPSC-derived neurons reveals that transcriptional inactivation correlates with loss of insulation at the differential boundary. Finally, re-wiring of chromatin loops during neural development is associated with transcriptional and functional changes. Importantly, differential loops in the fetal cortex are associated with autism GWAS loci, suggesting a neuropsychiatric disease mechanism affecting the chromatin interactome. Furthermore, neural development involves gaining enhancer-promoter loops that upregulate genes that control synaptic activity. Altogether, our study provides multi-scale insights on the 3D genome in the human brain.

Segmentation Head Networks with Harnessing Self-Attention and Transformer for Insulator Surface Defect Detection

Current methodologies for insulator defect detection are hindered by limitations in real-world applicability, spatial constraints, high computational demand, and segmentation challenges. Addressing these shortcomings, this paper presents a robust fast detection algorithm combined segmentation head networks with harnessing self-attention and transformer (HST-Net), which is based on the You Only Look Once (YOLO) v5 to recognize and assess the extent and types of damage on the insulator surface. Firstly, the original backbone network is replaced by the transformer cross-stage partial (Transformer-CSP) networks to enrich the network’s ability by capturing information across different depths of network feature maps. Secondly, an insulator defect segmentation head network is presented to handle the segmentation of defect areas such as insulator losses and flashovers. It facilitates instance-level mask prediction for each insulator object, significantly reducing the influence of intricate backgrounds. Finally, comparative experiment results show that the positioning accuracy and defect segmentation accuracy of the proposed both surpass that of other popular models. It can be concluded that the proposed model not only satisfies the requirements for balance between accuracy and speed in power facility inspection, but also provides fresh perspectives for research in other defect detection domains.

Modeling epigenetic lesions that cause gliomas

Epigenetic lesions that disrupt regulatory elements represent potential cancer drivers. However, we lack experimental models for validating their tumorigenic impact. Here, we model aberrations arising in isocitrate dehydrogenase-mutant gliomas, which exhibit DNA hypermethylation. We focus on a CTCF insulator near the PDGFRA oncogene that is recurrently disrupted by methylation in these tumors. We demonstrate that disruption of the syntenic insulator in mouse oligodendrocyte progenitor cells (OPCs) allows an OPC-specific enhancer to contact and induce Pdgfra, thereby increasing proliferation. We show that a second lesion, methylation-dependent silencing of the Cdkn2a tumor suppressor, cooperates with insulator loss in OPCs. Coordinate inactivation of the Pdgfra insulator and Cdkn2a drives gliomagenesis invivo. Despite locus synteny, the insulator is CpG-rich only in humans, a feature that may confer human glioma risk but complicates mouse modeling. Our study demonstrates the capacity of recurrent epigenetic lesions to drive OPC proliferation invitro and gliomagenesis invivo.

Design, wheel-rail interaction and testing of an innovative reinforced smooth transition insulated rail joint

Insulated Railway Joints (IRJ) fail mainly because of repeated shocks in the end post region, characterized by a largely reduced stiffness, causing loss of insulation (lipping), star cracks in the fishbolt holes and eventually broken rails leading to possible derailments. Laboratory tests to qualify IRJs are inadequate as they do not replicate impact loads. An innovative, reinforced joint named ABJ, made of forged shallow depth switch rails with a long, inclined cut and a thick reinforcing steel baseplate is introduced in the paper. It doesn’t show a dip angle in the transition area, resulting in smooth wheel-rail transition forces preventing rail damage, impact noise, vibrations and ballast deterioration. It is designed to be laid on standard sleepers and it can be installed on standard track. An innovative cable routing allows plain and continuous tamping operations optimizing track behaviour and degradation in the long term. Impact noise typical of rail joints is eliminated and the estimated life is theoretically infinite. The paper describes the static and dynamic behaviour of the ABJ as well as the wheel-rail interaction obtained by numerical simulations and a partial full-scale validation of the new joint.

Immature feathers preserved in Burmite provide evidence of rapid molting in enantiornithines

Fossil feathers are recorded in the greatest fidelity in amber. A new specimen of Cenomanian aged Burmese amber provides the first unequivocal evidence of immature feathers in the Mesozoic fossil record. The small, clear piece, identified as aerial amber, preserves a cluster of body feathers with their basal portions encased in keratinous sheaths. The feathers are identified as belonging to a young enantiornithine individual based on the combination of preserved feather morphotypes, degree of feather asymmetry in the single preserved remix, their diminutive size, and because only enantiornithines have so far been recovered from these amber deposits. The body feathers are all at approximately the same stage of development suggesting that immature enantiornithines rapidly molted body feathers. This interpretation is supported by evidence from lithic specimens of juveniles from the Lower Cretaceous Jehol group that preserve immature feathers throughout the body. This specimen contributes to evidence that indicates enantiornithines hatched flight ready, with fully developed remiges, but with sparse body plumage that was simultaneously replaced during the prejuvenal molt. Rapid molts indicate periodic increases in thermostatic costs due to the temporary loss of insulation. This information leads to an intriguing new hypothesis regarding the extinction of Enantiornithes: that periods of increased thermostatic cost during early ontogeny created untenable energetic budgets during the asteroid induced impact winter, which resulted in both decreased global temperature and resource scarcity. High energetic budgets are associated with extinction vulnerability and may have been a major factor underpinning the extinction of this clade.

Abstract 3479: Modeling epigenetic lesions that cause gliomas

Abstract Epigenetic lesions that disrupt gene regulatory elements and expression are increasingly recognized as potential drivers of human cancers. However, we currently lack the in vitro and in vivo models required to functionally validate such lesions and their tumorigenic impact. Here we model aberrations that arise in Isocitrate Dehydrogenase (IDH) mutant lower-grade gliomas, which exhibit profound DNA hypermethylation as a direct consequence of mutant IDH. DNA hypermethylation may promote gliomagenesis by silencing tumor suppressor genes or, alternatively, by activating proto-oncogenes through disruption of CCCTC-binding factor (CTCF) insulators. CTCF insulator sites define the three-dimensional shape of the genome by dictating the boundaries of topologically associated domains (TADs). Enhancers and promoters can interact when located in the same TAD but are restricted from interacting across different TADs. In IDH mutant gliomas, CpG sites around CTCF binding sites are frequently methylated, effectively compromising CTCF binding and thus TAD organization, allowing for cross-TAD interactions and aberrant activation of genes. We discovered a CTCF insulator downstream of the PDGFRA proto-oncogene that is recurrently disrupted in IDH mutant gliomas. We demonstrate that disruption of the syntenic insulator in mouse oligodendrocyte progenitor cells (OPCs) allows an OPC-specific enhancer to contact and induce Pdgfra, thereby increasing proliferation. In contrast, insulator disruption did not affect Pdgfra expression in neural progenitor cells (NPCs), which lack the enhancer. We also model a second recurrent epigenetic lesion in IDH mutant gliomas, the methylation-dependent silencing of the CDKN2A tumor suppressor. We show that inactivation of Cdkn2a/p19ARF by de novo promoter methylation or mutation drives OPC proliferation and cooperates with Pdgfra insulator loss. Finally, we use lentiviruses to coordinately inactivate the Pdgfra insulator and Cdkn2a in mouse corpus callosum, resulting in low-grade gliomagenesis in vivo with histological features reminiscent of human IDH mutant gliomas. Our study recapitulates recurrent epigenetic lesions in mouse models and demonstrates that the combination of Pdgfra activation and Cdkn2a silencing can transform OPCs in vitro and drive gliomagenesis in vivo. Citation Format: Gilbert J. Rahme, Nauman M. Javed, Kaitlyn L. Puorro, Shouhui Xin, Volker Hovestadt, Sarah E. Johnstone, Bradley E. Bernstein. Modeling epigenetic lesions that cause gliomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3479.

The Lifetime Prediction and Insulation Failure Mechanism of XLPE for High-Voltage Cable

The performance parameters and service life of the insulation layer of high-voltage cables are the key to ensure safe cable operation. Through extracting the mechanical parameters of high voltage cable insulation layer under different thermal aging temperatures, a normal linear regression model is established to predict the service life of high voltage cables. Meanwhile, the physicochemical characteristics such as microscopic morphology and molecular structure changes of the cable insulation layer are analyzed, the dielectric properties and breakdown field strength under ac condition are tested and the macroscopic electrical properties of the insulation layer are studied, and the insulation failure mechanism is further analyzed. The experimental results show that the elongation at break retention rate of cross-linked polyethylene (XLPE) increases slowly with the aging time, and then decreases rapidly when it reaches 50% of the initial elongation at break retention rate. The normal linear regression prediction model is established based on the Arrhenius formula, and it can be obtained the life endpoint of XLPE high voltage cable about 65 years at an operating temperature of 70 °C. Further analysis, under the action of heat and oxygen, the crystal zone structure of cable insulation is seriously damaged, and the carbonyl index is significantly increased. Accordingly, when the aging failure point is reached, the dielectric permittivity and dielectric loss of insulation are significantly increased, and the breakdown performance is significantly decreased. The work has an important guiding significance for insulation condition assessment and life prediction of high voltage cable.

Multiscale 3D genome reorganization during skeletal muscle stem cell lineage progression and aging.

Little is known about three-dimensional (3D) genome organization in skeletal muscle stem cells [also called satellite cells (SCs)]. Here, we comprehensively map the 3D genome topology reorganization during mouse SC lineage progression. Specifically, rewiring at the compartment level is most pronounced when SCs become activated. Marked loss in topologically associating domain (TAD) border insulation and chromatin looping also occurs during early activation process. Meanwhile, TADs can form TAD clusters and super-enhancer-containing TAD clusters orchestrate stage-specific gene expression. Furthermore, we uncover that transcription factor PAX7 is pivotal in enhancer-promoter (E-P) loop formation. We also identify cis-regulatory elements that are crucial for local chromatin organization at Pax7 locus and Pax7 expression. Lastly, we unveil that geriatric SC displays a prominent gain in long-range contacts and loss of TAD border insulation. Together, our results uncover that 3D chromatin extensively reorganizes at multiple architectural levels and underpins the transcriptome remodeling during SC lineage development and SC aging.

Thermal energy storage in concrete: Review, testing, and simulation of thermal properties at relevant ranges of elevated temperature

This study examines the thermal performance of concrete used for thermal energy storage (TES) applications. The influence of concrete constituents (aggregates, cementitious materials, and fibers) on the thermal conductivity and specific heat are summarized based on literature and via experimentation at elevated temperatures. It is indicated that concrete with siliceous aggregate, low water/cement ratios, and steel fibers produces better overall thermal properties. The results of literature review and laboratory testing are used for numerical simulation to evaluate the impact of concrete thermal property variability on TES capabilities. The TES module consists of the heat exchanger and surrounding concrete as the storage media. Both idealized cases without heat loss and realistic cases with insulation and heat losses are considered. The result shows that conventional concrete mixes can be tailored to decrease the module charge/discharge durations and increase the amount of thermal energy storage.

Thermal comfort analysis of auto-racing suits using a dynamic thermal manikin

Motorsports athletes compete at high speeds for, on average, three to four hours in a cockpit that can reach temperatures of 50°C. While engineers have worked to create a faster car and safer conditions, the comfort of the driver is often sacrificed. Motorsports governing bodies require that a driver’s racing suit meet at least one of several certification levels for thermal protection. While much research and testing go into certification, there continues to be a lack of information in the body of research regarding the impact of the racing suit on thermal comfort and heat stress. Therefore, the purpose of this research was to determine the impact of auto-racing personal protective clothing on the thermal comfort of race car drivers by utilizing a thermal manikin to observe the thermal insulation, evaporative resistance, and total heat loss (THL) of standard racing suits. Racing suit systems of varying SFI Foundation, Inc. (SFI) certification levels were purchased and analyzed using an ANDI sweating thermal manikin in an environmental chamber. Results from this research demonstrate that the average predicted THL for an SFI compliant racing ensemble is 172 W/m2. Findings indicate it is more beneficial for thermal comfort to wear a lower rated suit with base layers as opposed to a higher rated suit without undergarments. More research must be done to better understand how the predicted THL for racing ensembles effects the human body when performing under race day conditions, and to determine a minimum THL benchmark for racing ensembles.

Effects of the magnetic field penetration into the metal on the Brillouin flow in a crossed-field gap

In this paper, the relativistic Brillouin flow in a crossed-field gap is investigated. For this, the case of a planar magnetron is considered. In contrast to previous studies, it is assumed that the electron discharge occurs in a timescale that is long compared to the magnetic diffusion time in the metal. It is found that the Brillouin flow properties and the overall scenario for the loss of magnetic insulation are different from the short pulse case. In particular, it is shown that two branches of equilibrium Brillouin flow solutions can coexist inside the gap region: one linearly stable and the other linearly unstable. As the parameters are varied, the two branches coalesce and cease to exist in a bifurcation that leads to a complete loss of magnetic insulation. Nevertheless, the mere existence of the unstable solution inside the gap is shown to affect the electron dynamics causing cathode–anode currents. An expression for the onset of the unstable solution is obtained and compared to the relativistic Hull cutoff condition for the short pulse case. It is found that the loss of magnetic insulation occurs for lower accelerating potentials in the present case. This effect is noticeable even for weakly relativistic cases.

Double Line-to-Ground Faults Detection Method in DC-AC Converters

Numerous electrical machines use power converters for their efficient operation. However, their insulations experience a fast deterioration due to high frequency electrical stresses. This loss of insulation can lead into ground faults, which are the most common electrical faults. Convectional protection relays are not specifically designed to protect electrical drives. Moreover, relays’ malfunction could be provoked because of commutation noises, or DC and AC fault current's components influence in their measurement. Therefore, if the fault is not detected in time, it can be developed into a more severe fault. This paper proposes a detection method for high resistance double line-to-ground faults in electrical drives based on a grounding resistor placed in the midpoint of the DC side. The method has been developed for DC/AC systems and it is based on the voltage measurement in the grounding resistor and in the AC phases. Afterwards, performing a frequency domain analysis of the grounding resistor voltage and comparing its fundamental harmonic phase differences with the AC voltage phasors, the double line-to-ground fault incipient zone (DC and/or AC) can be detected, and also, the DC faulty pole or AC faulty phase can be discerned. The method has been verified through computer numerous simulations and experimental tests in a 140 kW power converter, obtaining satisfactory results in the fault detection. However, the exact location of each ground fault still being incognita.

Effect of plasma irradiation on the electrical characteristics of the PMMA-PS/Al2O3 nanocomposites

A nanocomposite consisting of (PMMA/PS) polymeric blend was prepared with the nanomaterials (Al2O3) by the casting method. The structural and dielectric characteristic were studied. The optical microscope photos demonstrated high homogeneousness and fine dispersal of Al2O3 NPs inside the blend polymer films, as well as the formation of charge transfer complex. The FTIR indicate to a physical interference between the polymer matrix and nanoparticles. SEM images showed agglomeration of small and close packed group of elliptical particles on the surface of the polymeric matrix as a result of adding different number of Al2O3 NPs. The insulator constant and the insulator loss of the (PMMA-PS/Al2O3) nanocomposites reduce with the rise in frequency, while the A.C electrical conductivity increases with increase of the frequency. The insulator constant, insulator loss and A.C electrical conductivity of (PMMA-PS/Al2O3) nanocomposites rises with raising of Al2O3 nanoparticles concentrations. The dielectric constant, dielectric loss and A.C electrical conductivity after irradiation have high values compared before irradiation which attributed to the plasma interact with the molecular of these nanocomposites. As a results of their improved electrical conductivity after irradiation, polymeric nanocomposites have been proposed for use in electronic devices, sensors, and batteries.