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Most power transformer failures are associated with the presence of corrosive sulfur compounds in mineral insulating oil, of which dibenzyl disulfide (DBDS) is the best known and most widespread corrosive sulfur compound. The oil of failed transformers usually contained DBDS, a compound with a pronounced affinity for the formation of copper (I) sulfide (Cu2S). Copper (I) sulfide is a compound that does not dissolve in oil, conducts electricity, and can be deposited on the paper insulation or copper conductor of the transformer. Created conductive paths between the windings can initiate turn-to-turn breakdown and failure of the transformer. Several technological procedures have been developed as a solution to oil corrosivity. The application of desulfurization technology developed by the Electrical Engineering Institute "Nikola Tesla" enables the efficient removal of DBDS and aging products from mineral insulation oils.

Dibenzyl disulfide (DBDS) is the major corrosive sulfur compound in mineral insulating oils, which will corrode the copper wires of windings in the oil-immersed power transformers and reactors and eventually cause operation failures. This paper studies the method to eliminate DBDS in insulation oils using the Polyethylene Glycol Sodium (Na-PEG) reagent. The preparation method of the Na-PEG reagent from NaOH and polyethylene glycol 400 is studied in the laboratory. The effect of the Na-PEG reagent dosage and reaction temperature on eliminating DBDS in insulating oils is studied, and a treatment process is recommended. An automatic processing device to remove DBDS from the transformer oil is developed, and the short-term electrical properties and long-term thermal stability of the insulating oil after the Na-PEG reagent treatment are tested. The results show that the Na-PEG reagent can efficiently eliminate DBDS in the insulating oil (the DBDS concentration decreases from 448 mg/kg to less than 5 mg/kg (undetectable) within 1 hour) and will not significantly negatively affect the oil properties such as the breakdown strength at the power frequency, dissipation factor or acidity. A preliminary exploration of the reaction mechanism is explored.

Background Although impulsive aggression (IA) and dysfunctional response inhibition (RI) are hallmarks of attention-deficit/hyperactivity disorder (ADHD) and disrupted behavioral disorders (DBDs), little is known about their shared and distinct deviant neural mechanisms. Aims and Methods Here, we selectively reviewed s/fMRI ADHD and DBD studies to identify disorder-specific and shared IA and RI aberrant neural mechanisms. Results In ADHD, deviant prefrontal and cingulate functional activity was associated with increased IA. Structural alterations were most pronounced in the cingulate cortex. Subjects with DBDs showed marked cortico-subcortical dysfunctions. ADHD and DBDs share similar cortico-limbic structural and functional alterations. RI deficits in ADHD highlighted hypoactivity in the dorso/ventro-lateral PFC, insula, and striatum, while the paralimbic system was primarily dysfunctional in DBDs. Across disorders, extensively altered cortico-limbic dysfunctions underlie IA, while RI was mostly associated with aberrant prefrontal activity. Conclusion Control network deficits were evidenced across clinical phenotypes in IA and RI. Dysfunctions at any level within these cortico-subcortical projections lead to deficient cognitive-affective control by ascribing emotional salience to otherwise irrelevant stimuli. The clinical implications of these findings are discussed. [ABSTRACT FROM AUTHOR]

Although dibenzyl disulfide (DBDS) is used as a mineral oil stabilizer, its presence in electrical transformer oil is associated as one of the major causes of copper corrosion and subsequent formation of copper sulfide. In order to prevent these undesirable processes, MY zeolites (with M = Li, Na, K, Cs, Cu or Ag) are proposed to adsorb molecularly DBDS. In this study, different MY zeolites are investigated at the DFT+D level in order to assess their ability in DBDS adsorption. It was found that CsY, AgY and CuY exhibit the best compromise between high interaction energies and limited S-S bond activation, thus emerging as optimal adsorbents for DBDS.

The effect of elevated temperatures induced by over currents on the performance of paper oil insulation of transformer is investigated. This study has been carried out in presence of spiked concentrations of Dibenzyl disulphide (DBDS) in mineral oil for understanding its effects on copper sulphide formation. The dielectric response of paper oil insulation when subjected to elevated temperatures is studied using frequency domain spectroscopy and measurement of polarization and depolarization current. It is observed that there are significant variations in tan ? (dissipation factor) and magnitudes of polarization and depolarization currents of paper oil insulation due to high temperatures. A characteristic peak of tan ? around 0.1 Hz in the FDS response is observed to indicate the presence of copper sulphide on paper. A FEM based thermal model is proposed to explain the distribution of thermal conductivity and temperature gradient in paper oil insulation due to copper sulphide deposits. [ABSTRACT FROM PUBLISHER]

This study investigated the inhibitory effects of adsorption treatment on the degradation of oil–paper insulation and corrosive sulphur in oil. A thermal ageing experiment at 130°C was conducted using five different adsorbents to adsorb some impurities in oil on the 15th day of a 30 day ageing test, the related characteristics of oil–paper insulation before and after the adsorption treatment were measured and analysed. Meanwhile, a thermal ageing experiment at 150°C was also conducted before using five different adsorbents to adsorb dibenzyl disulphide (DBDS) in oil, energy dispersive X‐ray was used to evaluate the degree of the corrosion of windings. The result indicates that adsorption treatment is an effective method to inhibit the degradation of oil–paper insulation. A molecular sieve, silica gel and activated alumina can effectively improve the performance of oil–paper insulation. By contrast, the antioxidant (2, 6‐di‐tert‐butyl‐p‐cresol) can be also adsorbed by adsorbents, which accelerate the ageing degradation of the insulating oil. On the other hand, the adsorbents can adsorb DBDS in oil, but cannot remove all DBDS. The effect achieved from silica gel is especially significant, which not only effectively improves the performance of oil–paper insulation but also adsorbs DBDS in oil. [ABSTRACT FROM AUTHOR]

Frick (2022) presented a narrative review of some literature and made several critical comments regarding the extension of the full psychopathy construct to research and classification of childhood disruptive behavior disorders (DBDs). His arguments cautioned against the use of the multicomponent concept of psychopathy for specification of DBDs for several reasons including definitional issues, symptom sequencing, specifier versus risk factor considerations, potential overlap with other disorders and criteria (e.g., ADHD), and concerns regarding harm. While I agree with Frick (2022) that we need to be cautious when extending personality constructs to the DBDs, the remaining arguments in his paper fall short of calling for the exclusion of psychopathy components in the examination of DBDs. Rather, the counterpoints in this paper further convince that the multidimensional model of psychopathy, when applied to the DBDs, could better facilitate understanding of the etiology and mechanisms for Conduct Disorder (CD), and, it may help us to predict the prognosis and treatment outcomes of children with various forms of DBDs such as CD and Oppositional Defiant Disorder (ODD). To have the most informative designs, future research should examine the broad construct to glean a better understanding of psychopathy and the DBDs. Further, research should continue to examine sequencing and external correlates at the component level and to test the incremental value of the multicomponent model of psychopathy to help us better comprehend how each component may facilitate our understanding of the types and severity of conduct problems exhibited by youth with DBDs (i.e., CD, ODD). [ABSTRACT FROM AUTHOR]

Presence of sulphur compounds in mineral transformer oil poses serious problems of corrosion of copper conductors. Thermal degradation of sulphur compounds like DBDS, 2- mercaptobenzothiozole and depletion of metal passivators like Irgamet 39 and BTA in mineral oil are complex processes. This paper presents results of investigations on degradation of mineral oil with these additives under thermal ageing in air and nitrogen. Efforts are made to explain independently the observed degradation of DBDS, 2-mercaptobenzothiozole and depletion of Irgamet 39 and BTA over a range of temperatures. The effect of sulphur compounds on the performance and depletion of BTA and Irgamet 39 are also explained. Irgamet 39 and BTA deplete in oil under thermal ageing to lower levels, but continue to protect copper from corrosion due to their adsorption by paper which acts as reservoir of metal passivators. The advantages and limitations in the use of Irgamet 39 and BTA are also discussed. To further substantiate the results of the study, effect of these additives on acid formation, interfacial tension and copper ion concentration are discussed. [ABSTRACT FROM AUTHOR]

The presence of corrosive sulphur compounds in mineral oil is a serious problem affecting the life of transformers. There are several techniques available to remove corrosive sulphur and among them the method of solvent extraction is useful for complete removal of sulphur compounds. In this investigation, laboratory experiments were carried out to validate method of solvent extraction for removal of sulphur compounds like Dibenzyl disulphide and Mercaptan sulphur from mineral oil. The optimum oil to solvent ratio, solvent to co-solvent ratio are investigated and discussed. Efficiency of method of solvent extraction for removal of sulphur compounds is demonstrated on a laboratory scale and further improvements to properties of mineral oil is proposed by the use of conventional reclamation techniques. [ABSTRACT FROM AUTHOR]

In recent years some unexpected operational failures of power transformers were attributed to the presence of the undeclared dibenzyl disulfide (DBDS) antioxidant in mineral insulating oils. This study examines the characteristics of DBDS and other antioxidants dissolved in a mineral oil. Acidities as neutralization numbers, interfacial tension values and depletion rates were obtained at 100°C for solutions of the antioxidants 2,6-di-tert-butyl-p-cresol (DBPC), 2,6-di-tert-butyl-phenol (DBP), dibenzyl disulfide (DBDS), 2-tert-butyl-p-cresol (2-t-BPC), Nphenyl- 1-naphthylamine, 1,2,3-Benzotriazol (BTA) and methylated-BTA in transformer mineral oil that have been exposed to an accelerated aging process involving flow of oxygen through them at a rate of 1.0 L h?1 over intervals of 24, 48, 72, 96 and 120 hours. The results show that the excellent antioxidant characteristics obtained for DBDS are lost when a copper plate is placed in the mineral oil sample. This is attributable to sulfur corrosion. The results also suggest that DBPC is most suited for use as an antioxidant in transformer mineral oil with DBP a close second. The higher depletion rates encountered for 2-t-BPC and N-phenyl-1- naphthylamine make them less suitable antioxidants. The lower effectiveness of 2-t-BPC as an antioxidant relative to DBPC and DBP may be attributed to the lesser steric hindrance of its ? OH group. The results for BTA and methylated-BTA and their higher depletion rates indicate that they would not be suitable antioxidants. [ABSTRACT FROM AUTHOR]

This paper reports the study of the Kr-Cl plasma chemistry in terms of the homogenous model of a dielectric barrier discharge and for two kinds of the applied voltage excitation shape. The effect of Cl concentration in the gas mixture, as well as gas pressure and power frequency on the discharge efficiency and the 222 nm photon generation, under typical experimental operating conditions, have been investigated and discussed. Calculations suggest that the overall conversion efficiency from electrical energy to ultraviolet emission in the lamp is in the range of 4.4-12 %, and it will be very affected at high chlorine percentage (>1 %) and high gas pressure (>200 Torr). A comparison between the sinusoidal and the burst excitation waveforms reveals that the burst excitation method provides an enhanced light source performance compared to the sinusoidal wave. [ABSTRACT FROM AUTHOR]

In this paper, we describe the deposition of PEO-like coatings using dielectric barrier discharges (DBDs) fed with aerosols of the TEGDME organic precursor in helium. By properly tuning plasma parameters such as aerosol/carrier flow ratio, frequency of the electric field applied and input power, the deposition process could be modulated to obtain coatings with variable PEO character, from 50% (cell adhesive) to 70% (nonfouling), which are interesting for surface modification of biomaterials and biomedical devices. [ABSTRACT FROM AUTHOR]

This paper reports the investigation of the excimer UV emission efficiency in Ne/Xe/HCl mixture in terms of the homogenous model of a dielectric barrier discharge. The computer model developed is based on the Ne/Xe/HCl gas mixture chemistry, the circuit and the Boltzmann equations. The effects of operating voltage, HCl concentration in the mixture as well as gas pressure on the discharge efficiency and the 172, and 308 nm photon generation, under typical experimental operating conditions, have been investigated and discussed. Calculations suggest that the overall conversion efficiency from electrical energy to VUV emission in the lamp is greater than 27%, and it will be very affected at high voltage amplitude and high gas pressure with a significant dependence on the HCl concentration in the gas mixture. [ABSTRACT FROM AUTHOR]

In this article, it is shown that a dibenzyl disulfide concentration greater than 10 mg⋅kg-1 in a nonpassivated oil makes the oil potentially corrosive, when tested in accordance with IEC 62535. The effect of Irgamet 39 on the oxidation stability of oil, and the thermal degradation of dibenzyl disulfide, including the role played by copper, are also discussed in the article. [ABSTRACT FROM AUTHOR]

The article presents a study which investigates the long-term efficacy and stability of an organic metal toluiltriazole-based passivator compound known as the Irgamet 39 in oil. It reveals that oil passivated with Irgamet 39 will turn back to its original corrosive status, which will eventually lead to the deposition of copper sulfide on copper and insulating paper. In addition, there was no recorded formation of copper sulfide in oil samples with more than 50 mg kg-1 of passivator.

Background: Effects of risperidone on cognitive function in children with disruptive behavior disorders (DBDs) and subaverage intelligence quotient (IQ) were assessed. Methods: Data from two 6-week, double-blind, placebo-controlled studies (n = 228) were combined, as were three 1-year, open-label studies (n = 688). Patients with DBDs and subaverage IQ, 5 to14 years, received placebo or risperidone .02 to .06 mg/kg/day. Cognitive measures included the Continuous Performance Task (CPT) and Verbal Learning Test for Children (VLT-C). Efficacy was assessed using the Nisonger Child Behavior Rating Form (NCBRF). Adverse events were collected via spontaneous report; sedation was assessed using visual analog scale. Results: Improvements on the NCBRF Conduct Problem subscale were significantly greater for risperidone- versus placebo-treated patients (−15.8 vs. −6.4, p < .0001) in short-term studies; significant reductions were observed in long-term studies (−16.3, p < .0001). No overall decline and some significant improvement in attention (CPT) and memory (VLT-C) were noted regardless of treatment in short-term studies. VLT-C improved significantly (p < .0001) for both groups, with no difference between treatment groups. Improvements in memory (VLT-C) and attention (CPT) were noted in long-term studies. Somnolence/sedation did not affect cognitive function. Conclusions: Cognitive function was not altered by risperidone in short-term studies and was maintained or improved with one year of treatment in children with DBDs and subaverage IQ, potentially representing age-appropriate gains. [Copyright &y& Elsevier]

Evidence is emerging which indicates that the anion transport activity of band 3 may be regulated. I review the molecular basis for regulation of the anion transport function of band 3 in terms of evidence showing that divalent anion transport involves a slow “hysteretic” transition between two functional states, mediated by interactions between subunits within band 3 oligomers. In addition, I briefly describe recent work from my laboratory where we have discovered a novel manifestation of slow conformational changes in band 3. This involves 4,4′-dibenzamido-2,2′-stilbenedisulfonate (DBDS) binding to a second, proton-activated site distinct from the primary stilbenedisulfonate site. This site is exposed on the outer aspect of band 3 when the pH is lowered (pK ∼5.0). This is the same pK as the protonation site on band 3 involved in divalent anion–proton co-transport (APCT) [J. Gen. Physiol. 79 (1982) 87]. Significantly, we have found that DBDS binding to this proton-activated site has unusually slow kinetics, and increasing DBDS concentration causes a decrease in the apparent pseudo-first-order rate constant. These results suggest that a slow conformational pre-equilibrium is the rate limiting step in DBDS binding to the proton-activated site on band 3 observed at low pH. Our results support an allosteric two-state model for regulation of divalent anion transport by band 3 oligomers involving a slow conformational transition and interactions between subunits [Biochemistry 31 (1992) 7301]. [Copyright &y& Elsevier]

Adults’ perceptions of children with disruptive behaviour disorders (DBDs), which usually interfere with socialization and referral of children to mental health services, might differ according to the child's sex. Given the importance of (a) the interactions between these children and their educators, and (b) early identification and referral, the impact of the child's sex on adults’ perceptions is an important factor to consider. To examine the role of gender-related expectations in the identification and referral of childhood DBDs by trainee nursery teachers. One hundred and fifty-eight female trainee nursery teachers (mean age = 20 years) at the Department of Early Childhood Education in Athens. Trainee nursery teachers’ perceptions of male and female children with DBDs were explored using a Greek version of the Parental Account of the Causes of Childhood Problems Questionnaire. Eighty-one participants answered questions about a set of disruptive behaviours ascribed to a boy and 77 about the same behaviour ascribed to a girl. DBDs ascribed to girls were considered to be no more severe or of greater concern than those ascribed to boys. Judgements of severity were related to concern in the same way for boys and girls. However, DBDs were regarded as less typical for girls than boys. The child's sex affected trainee teachers’ judgements of typicality, but not severity, of children's behaviour problems. The implications of this finding for socialization practices and referral attitudes are discussed. [ABSTRACT FROM AUTHOR]

The time course of binding of the fluorescent stilbene anion exchange inhibitor, DBDS (4,4′-dibenzamido-2,2′-stilbene disulfonate), to band 3 can be measured by the stopped-flow method. We have previously used the reaction time constant, τ, to obtain the kinetic constants for binding and, thus, to report on the conformational state of the band 3 binding site. To validate the method, we have now shown that the ID (0.3±0.1 μ m) for H-DIDS (4,4′-diisothiocyano-2,2′-dihydrostilbene disulfonate) inhibition of τ is virtually the same as the ID (0.47±0.04 μ m) for H-DIDS inhibition of red cell Cl flux, thus relating τ directly to band 3 anion exchange. The specific glucose transport inhibitor, cytochalasin B, causes significant changes in τ, which can be reversed with intracellular, but not extracellular, d-glucose. ID for cytochalasin B modulation of τ is 0.1±0.2 μ m in good agreement with K=0.06±0.005 μ m for cytochalasin B binding to the glucose transport protein. These experiments suggest that the glucose transport protein is either adjacent to band 3, or linked to it through a mechanism, which can transmit conformational information. Ouabain (0.1 μ m), the specific inhibitor of red cell Na,K-ATPase, increases red cell Cl exchange flux in red cells by a factor of about two. This interaction indicates that the Na,K-ATPase, like the glucose transport protein, is either in contact with, or closely linked to, band 3. These results would be consistent with a transport protein complex, centered on band 3, and responsible for the entire transport process, not only the provision of metabolic energy, but also the actual carriage of the cations and anions themselves. [ABSTRACT FROM AUTHOR]

In separated outer medullary collecting duct (MCD) cells, the time course of binding of the fluorescent stilbene anion exchange inhibitor, DBDS (4,4′-dibenzamido-2,2′-stilbene disulfonate), to the MCD cell analog of band 3, the red blood cell (rbc) anion exchange protein, can be measured by the stopped-flow method and the reaction time constant, τ, can be used to report on the conformational state of the band 3 analog. In order to validate the method we have now shown that the ID (0.5±0.1 μ m) for the H-DIDS (4,4′-diisothiocyano-2,2′-dihydrostilbene disulfonate) inhibition of τ is in agreement with the ID, (0.94±0.07 μ m) for H-DIDS inhibition of MCD cell Cl flux, thus relating τ directly to anion exchange. The specific cardiac glycoside cation transport inhibitor, ouabain, not only modulates DBDS binding kinetics, but also increases the time constant for Cl exchange by a factor of two, from τ=0.30±0.02 sec to 0.56±0.06 sec (30 mm NaHCO). The ID for the ouabain effect on DBDS binding kinetics is 0.003±0.001 μ m, so that binding is about an order of magnitude tighter than that for inhibition of rbc K flux ( K,=0.017 μ m). These experiments indicate that the Na,K-ATPase, required to maintain cation gradients across the MCD cell membrane, is close enough to the band 3 analog that conformational information can be exchanged. Cytochalasin E (CE), which binds to the spectrin/actin complex in rbc and other cells, modulates DBDS binding kinetics with a physiological ID (0.076±0.005 μ m); 2 μ m CE also more than doubles the Cl exchange time constant from 0.20±0.04 sec to 0.50±0.08 sec (30 mm NaHCO). These experiments indicate that conformational information can also be exchanged between the MCD cell band 3 analog and the MCD cell cytoskeleton. [ABSTRACT FROM AUTHOR]

A membrane protein that is immunochemically similar to the red cell anion exchange protein, band 3, has been identified on the basolateral face of the outer medullary collecting duct (MCD) cells in rabbit kidney. In freshly prepared separated rabbit MCD cells, M.L. Zeidel, P. Silva and J.L. Seifter ( J. Clin. Invest. 77:1682-1688, 1986) found that Cl/HCO exchange was inhibited by the stilbene anion exchange inhibitor, DIDS (4,4′-diisothiocyano-2,2′-disulfonic stilbene), with a K similar to that for the red cell. We have measured the binding affinities of a fluorescent stilbene inhibitor, DBDS (4,4′-dibenzamido-2,2′-disulfonic stilbene), to MCD cells in 28.5 mM citrate and have characterized both a high-affinity site ( K=93±24 mM) and a lower affinity site ( K=430±260 nM), which are closely similar to values for the red cell of 110±51 nM for the high-affinity site and 980±200 nM for the lower affinity site (A.S. Verkman, J.A. Dix & A.K. Solomon, J. Gen. Physiol. 81:421-449, 1983). When Cl replaces citrate in the buffer, the two sites collapse into a single one with K=1500±400 nM, similar to the single K=1200±200 nM in the red cell (J.A. Dix, A.S. Verkman & A.K. Solomon, J. Membrane Biol. 89:211-223, 1986). The kinetics of DBDS binding to MCD cells at 0.25 μM are characterized by a fast process, τ=0.14±0.03 sec, similar to τ=0.12±0.03 sec in the red cell. These similarities show that the physical chemical characteristics of stilbene inhibitor binding to MCD cell 'band 3' closely resemble those for red cell band 3, which suggests that the molecular structure is highly conserved. [ABSTRACT FROM AUTHOR]

We have previously shown that the human red cell glucose transport protein and the anion exchange protein, band 3, are in close enough contact that information can be transmitted from the glucose transport protein to band 3. The present experiments were designed to show whether information could be transferred in the reverse direction, using changes in tryptophan fluorescence to report on the conformation of the glucose transport protein. To see whether tryptophan fluorescence changes could be attributed to the glucose transport protein, we based our experiments on procedures used by Helgerson and Carruthers [Helgerson, A.L., Carruthers, A., (1987) J. Biol. Chem. 262:5464-5475] to displace cytochalasin B (CB), the specific d-glucose transport inhibitor, from its binding site on the inside face of the glucose transport protein, and we showed that these procedures modified tryptophan fluorescence. Addition of 75 mm maltose, a nontransportable disaccharide which also displaces CB, caused a timedependent biphasic enhancement of tryptophan fluorescence in fresh red cells, which was modulated by the specific anion exchange inhibitor, DBDS (4,4′-dibenzamido-2,2′-stilbene disulfonate). In a study of nine additional disaccharides, we found that both biphasic kinetics and DBDS effects depended upon specific disaccharide conformation, indicating that these two effects could be attributed to a site sensitive to sugar conformation. Long term (800 sec) experiments revealed that maltose binding (±DBDS) caused a sustained damped anharmonic oscillation extending over the entire 800 sec observation period. Mathematical analysis of the temperature dependence of these oscillations showed that 2 μ m DBDS increased the damping term activation energy, 9.5±2.8 kcal mol deg, by a factor of four to 39.7±5.1 kcal mol deg, providing strong support for the view that signalling between the glucose transport protein and band 3 goes in both directions. [ABSTRACT FROM AUTHOR]

Although dibenzyl disulfide (DBDS) is used as a mineral oil stabilizer, its presence in electrical transformer oil is associated as one of the major causes of copper corrosion and subsequent formation of copper sulfide. In order to prevent these undesirable processes, MY zeolites (with M = Li, Na, K, Cs, Cu or Ag) are proposed to adsorb molecularly DBDS. In this study, different MY zeolites are investigated at the DFT+D level in order to assess their ability in DBDS adsorption. It was found that CsY, AgY and CuY exhibit the best compromise between high interaction energies and limited S-S bond activation, thus emerging as optimal adsorbents for DBDS. [ABSTRACT FROM AUTHOR]