scholarly journals Tribo-electricity and friction. III.—Solid elements and textiles

1. No systematic investigation on this subject has yet been attempted. The efforts made to group these materials in a series according to the charges generated when they are rubbed two at a time are of uncertain value because of (1) impurities of substance and surface, (2) indeterminate initial surface strains. Moreover, the general practice has been to rub the solids when held, one in each hand. A more reliable method is to mount the bodies in a mechanism which ensures that the same parts of them come into contact at each fresh stroke. In the present research, the elements, mostly metals, are those specified in the preceding paper. The textiles are made and cleansed as described in an earlier paper. Silk, cotton and linen in our experience behave reliably when fully cleaned. The other great textile material, wool, is more oily and cannot be readily cleansed; so is less trustworthy. We therefore at present confine ourselves to one animal and one vegetable textile, choosing the pure samples of silk and cotton specified in the above paper. Also filter paper, another convenient fabric, is used after being boiled in several lots of distilled water. As the silk and cotton are treated with boiling chloroform, we tried exhausting the filter paper in this solvent to see if such treatment affected the cellulose in any way; but no effect on the properties of the paper could be found.

Author(s):  
Juliana Martins de Mesquita Matos ◽  
Rosana De Carvalho Cristo Martins ◽  
Valéria Regina Bellotto ◽  
Lilian Gomes da Silva Rocha ◽  
Eloiza Aparecida Barbosa ◽  
...  

Dalbergia miscolobium or Jacarandá do Cerrado is a species of legume in the Fabaceae family. It occurs in the sensu stricto Cerrado and in the dystrophic cerradão. It shows potential for landscaping and for recovering damaged areas. It is an endangered species and therefore is protected by the law that prevents cut in areas of the Federal District (Decree No. 14.783/93). The purpose of this study was to determine the best procedure to prepare seeds of Dalbergia miscolobium to assess viability in the tetrazolium test. We carried out the following treatments: i) hydration on filter paper at 25 ° C, ii) hydration on filter paper at 25 ° C followed by a cut in the tegument and iii) hydration on filter paper at 25 ° C followed bya complete removal of the tegument. The results were analyzed using analysis of variance and the Tukey range test. The analyzes showed that the best procedure to prepare seeds of Dalbergia miscolobium is the treatment in which there is a hydration followed by the complete removal of the integument. Where 78% of the seeds showed uniform staining, indicating that the seeds analyzed are of good quality. The other treatments, hydration and hydration followed by cutting, showed respectively 35% and 41% of viable seeds. RESUMO A Dalbergia miscolobium ou Jacarandá do Cerrado é uma espécie de leguminosa da família Fabaceae. Ocorre no sentido stricto Cerrado e no cerradão distrófico. Possui potencial para paisagismo e para recuperar áreas degradadas. É uma espécie ameaçada de extinção e, portanto, está protegida pela lei que previne o corte em áreas do Distrito Federal (Decreto 14.783 / 93). O objetivo deste estudo foi determinar o melhor procedimento de prepararação das sementes de Dalbergia miscolobium para serem submetidas à análise de viabilidade pelo teste de tetrazólio. Foram realizados os seguintes tratamentos: i) hidratação em papel de filtro a 25 ° C, ii) hidratação em papel de filtro a 25 ° C seguida de um corte no tegumento e iii) hidratação em papel de filtro a 25 ° C seguido de remoção completa do tegumento. Os resultados foram analisados utilizando-se a análise de variância e o teste de médias de Tukey. As análises mostraram que o melhor procedimento para preparar sementes de Dalbergia miscolobium é o tratamento em que há uma hidratação seguida pela remoção completa do tegumento, onde 78% das sementes apresentaram coloração uniforme, indicando que as sementes analisadas são de boa qualidade. Os demais tratamentos, hidratação e hidratação seguida de corte, mostraram respectivamente 35% e 41% de sementes viáveis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cicero Antônio Mariano dos Santos ◽  
Joacir do Nascimento ◽  
Kelly Cristina Gonçalves ◽  
Giovani Smaniotto ◽  
Leonardo de Freitas Zechin ◽  
...  

AbstractSpodoptera frugiperda is a pest of economic importance for several crops with resistance reports to Bt crops and pesticides. Eco-friendly Bt biopesticides may be an alternative to chemical insecticides due to their selectivity and specificity. However, the efficacy of Bt biopesticides may be influenced by the association with other chemicals, such as adjuvants. This study evaluated the compatibility and toxicity of Bt biopesticides mixed with adjuvants for the control of S. frugiperda. The treatments included the association of Dipel SC and Dipel PM with adjuvants. Compatibility tests were used to evaluate the Bt mixture. Bt suspensions obtained from mixtures of Bt and adjuvants at 106 and 3 × 108 spores/mL−1 were used to evaluate S. frugiperda mortality and distilled water was used as the control. The addition of the adjuvant LI increased growth and sporulation, indicating compatibility with Bt biopesticides. The other adjuvants were toxic to reducing Bt growth and sporulation. Only the mixture of Bt with LI and Bt alone was effective to S. frugiperda. The addition of adjuvants to Bt biopesticide affect the Bt sporulation, growth and mortality.


1925 ◽  
Vol 9 (2) ◽  
pp. 123-136
Author(s):  
Howard J. Shaughnessy ◽  
Katharine I. Criswell

1. The strain of Bacterium coli used in these experiments multiplies in distilled water at pH 6.0 and pH 8.0 and in Ringer-Locke solution at pH 6.0. Under all the other conditions studied the numbers decrease with the passage of time. 2. The electrophoretic charge of the cells is highest in distilled water at pH 6.0 and pH 8.0. Under all other conditions studied the velocity of migration is decreased, but the decrease is immediate and is not affected by more prolonged exposure. 3. A strongly acid solution (pH 2.0) causes a rapid death of the cells and a sharp decrease in electrophoretic charge, sometimes leading to complete reversal. 4. A strongly alkaline solution (pH 11.0) is almost as toxic as a strongly acid one, although in distilled water the organisms survive fairly well at this reaction. Electrophoretic charge, on the other hand, is only slightly reduced in such an alkaline medium. 5. In distilled water, reactions near the neutral point are about equally favorable to both viability and electrophoretic charge, pH 8.0 showing slightly greater multiplication and a slightly higher charge than pH 11.0. In the presence of salts, however, pH 8.0 is much less favorable to viability and somewhat more favorable to electrophoretic charge than is pH 6.0. 6. Sodium chloride solutions, in the concentrations studied, all proved somewhat toxic and all tended to depress electrophoretic charge. Very marked toxicity was, however, exhibited only in a concentration of .725 M strength or over and at pH 8.0, while electrophoretic migration velocity was only slightly decreased at a concentration of .0145 M strength. 7. Calcium chloride was more toxic than NaCl, showing very marked effects in .145 M strength at pH 8.0 and in 1.45 M strength at pH 6.0. It greatly depressed electrophoretic charge even in .0145 M concentration. 8. Ringer-Locke solution proved markedly stimulating to the growth of the bacteria at pH 6.0 while at pH 8.0 it was somewhat toxic, though less so than the solutions of pure salts. It depressed migration velocity at all pH values, being more effective than NaCl in this respect, but less effective than CaCl2. 9. It would appear from these experiments that a balanced salt solution (Ringer-Locke's) may be distinctly favorable to bacterial viability in water at an optimum reaction while distinctly unfavorable in a slightly more alkaline solution. 10. Finally, while there is a certain parallelism between the influence of electrolytes upon viability and upon electrophoretic charge, the parallelism is not a close one and the two effects seem on the whole to follow entirely different laws.


Author(s):  
João Felipe Besegato ◽  
Gabriela Dos Santos Ribeiro Rocha ◽  
Marlene De Sousa Amorim ◽  
Fabio Martins Salomão ◽  
Daniel Poletto ◽  
...  

Objective: to measure pH values of bleaching agents that are indicated to intracoronal bleaching technique in different time intervals. Methods: Each group (G) received five samples (n=5): G1 – distilled water (AD); G2 – hydrogen peroxide (H2O2) 30%; G3 – sodium perborate (PbS) + AD; G4 – PbS + H2O2 30%; G5 – sodium percarbonate (PcS) + AD; and G6 – PcS + H2O2 30%. pH values were stated using a digital pHmeter, in different time intervals: immediately after handling (T0), 24 hours (T1) and 168 hours after handling (T2). The results were submitted to statistical analysis through Kruskal-Wallis and Mann Whitney tests, in this order, allowing multiple comparisons among the groups. To verify the effect of time in each group, Friedman test was applied. Results: In the evaluation of the effect of time in each group, it was observed that G2 presented acid behavior, while the other groups exhibited values close to neutrality or alkaline. Conclusions: H2O2 30% was the only agent that showed acidic behavior in every evaluation time. Meanwhile, PcS + H2O had the highest pH values.


2007 ◽  
Vol 59 (1) ◽  
pp. 145-149 ◽  
Author(s):  
F.F. Fernandes ◽  
R.N. Leles ◽  
I.G. Silva ◽  
E.P.S. Freitas

The larvicidal potential of the crude ethanolic extracts (CEE) of the stem peel of Sapindus saponaria was evaluated against Rhipicephalus sanguineus. Lethal concentrations (LC), were calculated by preparing CEE solutions at different concentrations in distilled water. Larvae fasted for 14-21 days were utilized in the bioassays, after incubation of engorged females collected from infested environments frequented by dogs in several neighborhoods of Goiânia, GO. Bioassays were performed in a specially constructed biological chamber for testing botanical acaricides, acclimatized to 27±1ºC, RH>80%. The larvae were counted on filter paper envelopes impregnated with the solutions or distilled water and larval mortality observed after 48h. S. saponaria showed good larvicidal activity (LC50 and LC99 of 1994 and 3922ppm, respectively) and the results demonstrated its potential as a botanical acaricide and an alternative control measure for R. sanguineus.


1976 ◽  
Vol 4 (3) ◽  
pp. 179-182 ◽  
Author(s):  
D M Lomas ◽  
J Gay ◽  
R N Midha ◽  
D L Postlethwaite

Three hundred and twelve patients suffering from painful conditions were admitted to a multicentre, double-blind controlled trial, conducted in general practice in which five analgesics—floctafenine (Idarac), paracetamol, aspirin, dihydrocodeine and pentazocine—were compared. Overall ratings of analgesic effect placed floctafenine first in rank order. Floctafenine was statistically significantly superior in effect to pentazocine but not to the other three agents as far as doctor ratings were concerned; and superior to both pentazocine and dihydrocodeine in the opinion of patients. Fewer patients experienced side-effects on floctafenine than on the other four analgesics and this difference between floctafenine and pentazocine, and floctafenine and dihydrocodeine was statistically significant.


2013 ◽  
Vol 655-657 ◽  
pp. 1917-1922 ◽  
Author(s):  
Cheng Ge Wu ◽  
Kang Ning Sun ◽  
Ai Min Li ◽  
Xiao Ning Sun

Purpose: To assess determination of Bacillus Calmette-Guerin(BCG) concentration integrated in delivery materials for intravesical infusion therapy of superficial bladder cancer. Material and Methods: The standard BCG solution was prepared and divided into two groups. One group was measured by spectrophotometer direct, the other group was determined by using enzyme mark instrument after the solution had cultured. The preliminary experiment study on BCG integrated delivery materials was finished by XTT method. Results: The wavelength of the characteristic peak changes with the variety of the concentration measured by spectrophotometer direct. The concentration of BCG which was embeded in integrated delivery materials for intravesical infusion therapy of superficial bladder cancer was linear with absorbance at 450nm by XTT method in the selected range. Conclusions: It is an incorrect way to measure BCG concentration like determining other solutions by the spectrophotometer immediately and direct. It is the simple, rapid and reliable method by XTT method to study on the performance of the BCG concentration integrated in delivery materials for Intravesical infusion therapy of superficial bladder cancer.


2007 ◽  
Vol 59 (3) ◽  
pp. 227-231 ◽  
Author(s):  
S. Zivkovic ◽  
M. Devic ◽  
B. Filipovic ◽  
Z. Giba ◽  
D. Grubisic

The influence of high NaCl concentrations on seed germination in both light and darkness was examined in the species Centaurium pulchellum, C. erythraea, C. littorale, C. spicatum, and C. tenuiflorum. Salt tolerance was found to depend on the life history of the seeds. To be specific, seeds of all five species failed to complete germination when exposed to continuous white light if kept all the time in the presence of 100-200 mM and greater NaCl concentrations. However, when after two weeks NaCl was rinsed from the seeds and the seeds were left in distilled water under white light for an additional two weeks, all species completed germination to a certain extent. The percent of germination not only depended on NaCl concentration in the prior medium, but was also species specific. Thus, seeds of C. pulchellum, C. erythraea, and C. littorale completed germination well almost irrespective of the salt concentration previously experienced. On the other hand, seeds of C. tenuiflorum completed germination poorly if NaCl concentrations in the prior media were greater than 200 mM. When seeds after washing were transferred to darkness for an additional 14 days, they failed to complete germination if previously imbibed on media containing NaCl concentrations greater than 400 mM. However, the seeds of all species, even if previously imbibed at 800 mM NaCl, could be induced to complete germination in darkness by 1 mM gibberellic acid. .


2016 ◽  
Vol 13 (4) ◽  
pp. 639-648
Author(s):  
Baghdad Science Journal

This study was designed to investigate the effect of the Clenbuterol drug in some physiological parameters of Liver, Kidney function and lipidprofie concentration. Fourty adult male rabbits were used in this study. The animals were randomly divided into four groups,the first group was given distilled water (control) ,while the other third groups were given (2,4,6 µg/kg) of Clenbuterol drug for 30 days. Blood samples were collected after 14 and 30 days of the treatment for biochemical study. Drug caused non significant increase(P


2018 ◽  
Vol 67 (2) ◽  
pp. 157-163
Author(s):  
Milan Jocković ◽  
Petar Čanak ◽  
Vladimir Miklič ◽  
Jelena Ovuka ◽  
Velimir Radić ◽  
...  

Summary A useful approach for improving seed germination and seedling growth is a seed priming technique. Application of the priming technique enhances water absorption, causing activation of metabolic activities in the seed. The objective of this study was to evaluate the effect of seed priming on germination parameters of safflower and to compare different priming techniques: priming by soaking and priming on filter paper. The priming treatments included hydropriming (distilled water) and osmopriming with 0.1% and 0.5% solutions of KNO3 for 8 and 16 hours. The experiment revealed significant difference between the priming treatments and the control. The highest germination (89.50%) was recorded within the priming treatments by soaking in the solution of 0.1% KNO3 and priming on filter paper moistened with 0.5% KNO3 for 8 hours. Considering germination index, mean germination time and time to 50% germination, the best results were obtained within hydropriming on filter paper for 16 hours. This study has shown that the priming techniques significantly improved germination parameters of safflower. Although priming on filter paper showed better results, the soaking technique – due to its simplicity, low cost and easiness of application – can be successfully used to improve germination parameters of safflower and increase the number of plants per unit of area and thus increase the seed yield per acreage.


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