Crosslinked polyethylene (XLPE) is a common material for power cable insulation due to its low cost, mechanical stability, and insulating nature. It is made by converting low-density polyethylene ...(LDPE) to a crosslinked variant using the chemical agent dicumyl peroxide (DCP). However, the crosslinking process leaves behind byproducts that may compromise the utility of the XLPE. For example, they can contribute to space charge buildup and degradation over time. Here, the thermally stimulated depolarization current (TSDC) technique is used to analyze the susceptibility of XLPE to charge buildup and the origins of the stored charge. Comparisons to LDPE are made to determine if DCP byproducts play a role. In general, three peaks are observed in both XLPE and LDPE, with only one being observed above room temperature. That homocharge peak arises from charge injection that occurs during poling, and has greater magnitude in LDPE than in XLPE. It's magnitude in XLPE can be controlled by the applied field, but the same cannot be said for LDPE. For the two other peaks observed, one is potentially attributable to polymer motion or glass transition phenomena, while the origin of the other is currently speculated to be related to moisture content.
The design of a novel wideband RF signal combiner suitable for LINC transmitters in CMOS technologies is presented in this paper. Compared to the conventional narrowband design, the wideband ...architecture achieves a small reflection coefficient (less than 0.3) suitable for wideband spread spectrum multi-user mobile systems. A 0.18 /spl mu/m CMOS wideband signal combiner, designed to add two 8GHz signals and deliver 1.5W to the antenna from 1V class F power amplifiers, is presented and compared to a narrowband design.
In this study, the byproduct-driven conduction current in LDPE was investigated. We built an experimental fixture to measure bulk conductivity in LDPE soaked with byproducts. Ohmic conduction was ...observed below 10 kV/mm. At above 10 kV/mm, space charge limited current (SCLC) predicts observed conduction in LDPE soaked with byproducts. It is found that the addition of byproducts introduces charge traps with discrete energy levels which dominate conduction. Degassed samples, on the other hand, show slopes of greater than 2.5 in a current-voltage log-log plot which was attributed to the charge traps with continuous energy levels. By analyzing the thickness dependence of the current, we observed a transition from electrode- to bulk-limited current at above 20 kV/mm for acetophenone- and α-cumyl alcohol-soaked samples. The α-methylstyrene-soaked samples only show electrode-limited current.
The intrinsic diffusion of the acetophenone in low density polyethylene (LDPE) is characterized with infrared mapping and it is found to be nearly Fickean with decaying diffusion coefficient over ...time. The impact of temperature on the diffusion coefficient is examined and an Arrhenius relationship is derived for the temperature dependence. To study the influence of electric field on the acetophenone diffusion, field-test cells were designed and constructed. The infrared mapping revealed presence of a gradient in the acetophenone concentration. Using the COMSOL simulation, we observed the higher acetophenone concentration near high electric field gradient regions. This is attributed to the dielectrophoresis phenomenon that occurs due to higher permittivity of the acetophenone molecules compared to the surrounding medium. The findings of this study help to understand where the byproducts migrate in high voltage power cables.
Pharmacological experiments were conducted to determine the neuronal mechanisms involved in the suppressive effects of the thyrotropin‐releasing hormone analog TA‐0910 on alcohol intake in ...alcohol‐preferring (P) rats. We previously reported that single intraperitoneal injections of TA‐0910 dose‐dependently reduced alcohol intake in P rats without altering fluid or total calorie intake; however, after several consecutive, once‐daily injections, P rats developed tolerance to the suppressive effects of TA‐0910 on alcohol intake and cross‐tolerance to like effects of the dopamine D2 agonist bromocriptine, but not to like effects of the serotonin uptake inhibitor fluoxetine. In the present study, rats were injected with vehicle or different doses of the D2 antagonist s (–)‐eticlopride (0.01 to 0.05 mg/kg) or the D1 antagonist R(+)‐SCH23390 (0.1 to 0.5 mg/kg) and 20 min later with TA‐0910 (0.75 mg/kg). Alcohol and water intakes were measured at 2,4,6, and 24 hr, and food was measured every 24 hr. Both s(–)‐eticlopride and R(+)‐SCH23390 produced modest reductions in alcohol intake alone; however, only s(–)‐eticlopride antagonized the suppressive effect of TA‐0910 on alcohol intake. In related experiments, it was confirmed that the dopamine D3 agonist 7‐hydroxy‐N,N‐di‐n‐propyl‐2‐aminotetralin reduced alcohol intake in P rats, and it was found that tolerance to this effect did not develop during or after seven consecutive once‐daily injections. Furthermore, this effect of 7‐hydroxy‐N,N‐di‐n‐propyl‐2‐aminotetralin was not diminished in rats made tolerant to the effect of TA‐0910 on alcohol intake. These data, those of previous studies, and recent preliminary findings support involvement of dopamine D2, but not D1 or D3 receptors in mediating the suppressive effect of TA‐0910 on alcohol intake of P rats.
FACETEQ Mavridou, I.; McGhee, J. T.; Hamedi, M. ...
Proceedings of the Virtual Reality International Conference - Laval Virtual 2017,
03/2017
Conference Proceeding
Faceteq prototype v.05 is a wearable technology for measuring facial expressions and biometric responses for experimental studies in Virtual Reality. Developed by Emteq Ltd laboratory, Faceteq can ...enable new avenues for virtual reality research through combination of high performance patented dry sensor technologies, proprietary algorithms and real-time data acquisition and streaming. Faceteq project was founded with the aim to provide a human-centred additional tool for emotion expression, affective human-computer interaction and social virtual environments. The proposed poster will exhibit the hardware and its functionality.
D and L isomers of aspartic acid beta-hydroxamate (respectively DAH and LAH) were compared for their in vitro and in vivo activity against the murine leukemia L5178Y and their tolerance in vivo in ...DBA/2 mice. DAH and LAH displayed comparable cytotoxic activity against L5178Y leukemia in vitro. Death of leukemia cells was observed at concentrations above 1.2 mM for both DAH and LAH. High concentrations of L-asparagine partially reversed the growth-inhibitory effects of DAH and LAH on L5178Y cells for concentrations of DAH and LAH lower than 0.6 mM. Intraperitoneal administration of DAH and LAH to mice showed that the LD10, LD50 and LD90 of DAH was 3- to 4-fold greater for DAH than for LAH. DAH was able to eradicate L5178Y tumors in mice without inducing toxic deaths, whereas LAH at comparable doses killed all the animals treated.
Experiments were carried out to examine the adjuvanticity of polar glycopeptidolipids of
Mycobacterium chelonae (pGPL-Mc) or the London rocket seed (LRS) when combined with diphtheria and tetanus ...toxoids in an oral immunization of the African green monkey. The results showed that none of the monkeys receiving diphtheria and tetanus toxoids combined with 25 mg/kg of pGPL-Mc showed an increase in the the level of diphtheria antitoxin (DA) on the third and sixth weeks following the first and the second immunizations. One monkey from this group responded with increased seroneutralizing antibodies 3 weeks after the third feeding. On the other hand, one monkey, 3 weeks after the first immunization, and three monkeys, 3 weeks after the second and third oral vaccinations, showed an increase in specific anti-diphtheria antibody responses when the toxoids were combined with 25 mg/kg of LRS. The anti-diphtheria antitoxin responses of monkeys receiving diphtheria and tetanus toxoids combined with 50 mg/kg of pGPL-Mc or 50 mg/kg of LRS were significantly enhanced compared to the groups administered 25 mg/kg of the two adjuvants. The increase was observed in four out of five pGPL-Mc administered and in three out of five LRS-receiving monkeys. The results show that pGPL-Mc induced the highest titres of anti-diphtheria antitoxin compared to LRS, whereas the level of anti-diphtheria antitoxin titre of the two monkeys receiving the toxoids alone was less than 0.1 IU/ml of serum throughout the experiment. According to the statistical analyses, no significant differences were recorded between the diphtheria antitoxin responses of monkeys following the first, second or third administration of LRS-adjuvated diphtheria and tetanus toxoids. However, a significant difference (
P ≤ 0.05) was observed in the diptheria antitoxin response between the first and the second immunization of monkeys administered with toxoids adjuvated with 50 mg/kg of pGPL-Mc. The tetanus antitoxin responses of all monkeys were less than 0.1 IU of antitoxin per millilitre of serum throughout the study, which is considered not to be protective. However, we have recorded an anti-tetanus antitoxin titre of more than 0.2 IU/ml of serum in one monkey that received diphtheria and tetanus toxoids combined with 50 mg/kg of pGPL-Mc.
Les essais ci-après ont eu pour but d'étudier le caractère adjuvant des glycopeptidolipides polaires extraits de
Mycobactérium chelonae (GPLp-Mc) et du London rocket seed (LRS) lorsqu'ils sont combinés avec l'anatoxine diphtérique et l'anatoxine tétanique et administrés par voie orale au singe vert africain. Les résultats montrent que les réponses en antitoxine diphtérique des singes ayant reçu les anatoxines diphtérique et tétanique avec 50 mg/kg de GPLp-Mc et 50 mg/kg de LRS ont été significantivement augmentées par rapport aux groupes qui ont reçu 25 mg/kg des deux adjuvants. L'augmentation du titre des antitoxines a été observée sur quatre des cinq singes ayant reçu GPLp-Mc et sur trois des cinq singes ayant reçus LRS. Les résultats montrent que GPLp-Mc induit des titres d'antitoxines diphtériques plus élevés par LRS alors que les titres d'antitoxines diphtériques des deux singes ayant reçu l'anatoxine seule étaient inférieurs à 0,1 UI/ml de sérum. Après analyse statistique, aucune différence significative n'a été observée entre les réponses en antitoxines diphtériques des singes après la première, la deuxième et la troisième administration d'anatoxines diphtérique et tétanique adjuvées avec LRS. Cependant une différence significative (
P ≤ 0,05) a été observée dans la réponse à l'antitoxine diphtérique entre la première, la deuxième immunisation des singes par les anatoxines diphtériques adjuvées avec 50 mg/kg de GPLp-Mc. Les réponses de tous les singes à l'anatoxine tétanique furent inférieures à 0,1 UI/ml d'antitoxine, quantité considérée comme non-protectrice. Cependant, nous avons observé un titre d'antitoxine tétanique supérieur à 0,2 UI chez un singe ayant reçu l'anatoxine diphtérique et tétanique associées à 50 mg/kg de GPLp/Mc.
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