scholarly journals Experimental Research on Rubber Compatibility of Drive Train oils used in Construction Machinery

2021 ◽  
Vol 2125 (1) ◽  
pp. 012018
Author(s):  
Haizhen An ◽  
Min Liu ◽  
Penghou Zhen ◽  
Li Chen

Abstract The compatibility of oil and rubber in the drive train system of construction machinery plays an important role in the safe and reliable operation of the system. In order to investigate the rubber compatibility of drive train system oil of construction machinery, the changes of rubber sheet volume and hardness before and after immersion of standard fluororubber (FKM2) and hydrogenated nitrile rubber (HNBR1) with 9 kinds of drive train system oil were tested. The results show that FKM2 has good rubber compatibility with drive train oil, and HNBR1 is only compatible with some drive train oil; The volume change rate and hardness change range of FKM2 are smaller than those of HNBR1.

2018 ◽  
Vol 7 (1) ◽  
pp. 8-17
Author(s):  
Mahsa Assadi

This study reports a pre-experimental research on the impact of metacognitive instruction on EFL learners’ metacognitive awareness and their listening performance. To obtain the goal of the study, a group of 30 Iranian intermediate EFL learners, including 14 males and 16 females, were selected randomly. Their ages range from 20 to 24. The participants took part in 16 weeks’ intervention program based on metacognitive pedagogical sequence consisted of five stages. The metacognitive awareness listening questionnaire (MALQ), and a listening test were also used to find changes in metacognitive awareness and listening performance before and after the treatment. The results of comparing pre and posttests scores revealed that metacognitive instruction raised the learners’ metacognitive awareness and helped them improve their listening comprehension ability.


Author(s):  
Е.Б. Ганина ◽  
Ю.В. Червинец ◽  
Н.В. Грудинин ◽  
В.Г. Шестакова ◽  
В.М. Червинец ◽  
...  

Цель исследования - охарактеризовать микробиологическую картину стоматита до и после его лечения высокоактивными культурами лактобацилл, дать оценку эффективности их применения при экспериментальном стоматите. Методика. Опыты проводились на 32 самках беспородных белых крыс массой 230 г. Моделирование стоматита включало 2 этапа: моделирование травматического стоматита и воспроизведение бактериального стоматита на базе травматического. У крыс контрольной и опытных серий на всех этапах эксперимента брали мазки с поверхности десен для характеристики микробиоценоза ротовой полости. Результаты. После обработки слизистой оболочки полости рта (СОПР) культурой патогенного штамма Staphylococcus aureus существенно снизились частота встречаемости и количество условно-патогенных микроорганизмов. Лечение стоматита у крыс культурами лактобацилл ( Lactobacillus 11 зв., Lactobacillus 2 п.рта, Lactobacillus 24 д.ст.) и их комбинацией приводило к снижению распространенности S. aureus вплоть до его исчезновения, а также к нормализации количества условно-патогенной микробиоты. Заключение. Исследования показали эффективность использования отдельных высокоактивных штаммов лактобацилл или их комбинации при лечении заболеваний СОПР, в частности бактериального стоматита. Aim. To characterize the microbiological picture of stomatitis in intact rats before and after the treatment with highly active cultured lactobacilli and to evaluate the effectiveness of this treatment in experiments on white rats. Methods. Experiments were carried out on 32 mongrel female white rats weighing 230 g. Smears were taken from the gum surface of control and experimental rats at all stages of the experiment to characterize the oral cavity microbiocenosis. Results. After treatment of the oral cavity with cultured Staphylococcus aureus , the occurrence and quantity of opportunistic microorganisms significantly decreased. The treatment of stomatitis in rats with cultured lactobacillus ( Lactobacillus 11 zv., Lactobacillus 2 p.r., Lactobacillus 24 d.st. and their combination) led to a decrease in S. aureus prevalence up to its extinction and to normalization of the quantitative composition of opportunistic microbiota. Conclusions. The study showed the effieacy of highly active lactobacillus strains individually or their combinations in the treatment of oral diseases, in particular, bacterial stomatitis.


2007 ◽  
Vol 30 (1) ◽  
pp. 47-49 ◽  
Author(s):  
Elaine Henna ◽  
Monica L Zilberman ◽  
Valentim Gentil ◽  
Clarice Gorenstein

OBJECTIVE: To test a reliable and easily administered frustration-induction procedure for experimental research. METHOD: One hundred volunteers (81 women, mean age ± SD 34.2 ± 8 years) physically and psychiatrically healthy submitted to the frustration induction procedure were prevented from reaching reward level scores. Subjective aggressiveness feelings related to frustration were self-rated in a 13-item visual analogue scale before and after the procedure. RESULTS: Significant increases in aggressiveness-related feelings were detected in 12 of the 13 items. This was consistent with the observed overt behavior of the subjects during the task. CONCLUSIONS: The frustration-induction procedure is a simple, easy to administer frustration-induction procedure that can be used in experimental studies in normal subjects.


2016 ◽  
Vol 43 (10) ◽  
pp. 865-874 ◽  
Author(s):  
Sheng-lin Wang ◽  
Qing-feng Lv ◽  
Hassan Baaj ◽  
Xiao-yuan Li ◽  
Yan-xu Zhao

Freeze–thaw action is considered to be one of the most destructive actions that can induce significant damage in stabilized subgrades in seasonally frozen loess areas. Laboratory tests including frost heave – thaw shrinkage and microstructure change during freeze–thaw cycles were conducted to evaluate the volume change rate of loess stabilized with cement, lime, and fly ash under the impact of cyclic freeze–thaw conditions. The loess specimens collapsed after eight freeze–thaw cycles (192 h), but most stabilized loess specimens had no visible damage after all freeze–thaw cycles were completed. All of the stabilized loess samples underwent a much smaller volume change than the loess alone after the freeze–thaw cycles. Although surface porosity and equivalent diameter of stabilized loess samples increased, the stabilized loess can retain its microstructure during freeze–thaw cycles when the cement content was less than 6%. To ensure freeze–thaw resistance of stabilized loess subgrades, the mix proportions of the three additives was recommended to be 4 to 5% cement, 6% lime, and 10% fly ash.


2019 ◽  
Vol 7 (3) ◽  
pp. 472-476
Author(s):  
Hay Citra Ningrat ◽  
Linda Mayasari

Purpose of Study: This research is talking about the use of Webtoons comic in speaking on the recount. The aim of this research is to know whether this media is effective in teaching speaking on the recount. Methodology: It is pre-experimental research with one group of pre test - post test. Thirty students in X-5 class at Muhammadiyah 1 high school Surabaya become the sample. The treatments had been done twice, so there are two pairs of results. Results: The results are administered and calculated by using SPSS 21 for windows (paired T-test). The means of pair 1 are 31.93 (pre-test 1) and 34.77(post test 1). Meanwhile, the means of pair 2 are 32.00 (pre test 2) and 35.77 (post test 2). The sig value for pair 1 is .00 and pair 2 is .00. Based on these figures, it can be said that there is any different before and after the implementation of teaching speaking performance on a recount by using Webtoons. Even the improvement of students’ speaking competence on recount is not much, for the students. Implications/Applications: Webtoons is an interactive teaching medium which makes them more enthusiastic, comfortable and easily arrange their text to be told.


2019 ◽  
Vol 11 (1) ◽  
pp. 114
Author(s):  
Kurniati Kurniati ◽  
Ervina Ervina

This study aims to determine the students’ speaking skill before and after applying Guessing Game and find out the effect of Guessing Game on the students’ speaking skill at the first semester of English education study program of STAIN Bengkalis. This research is experimental research that involved 18 students at the first semester of English Education Study Program of STAIN Bengkalis. Speaking test was implemented in order to collect the students’ speaking performance, and the collected data were quantitatively analyzed. Guessing Game has a less significant effect in improving the students’ speaking skill at the first semester of English education study program of STAIN Bengkalis. This is evidenced by the results of t-o (1,3) smaller than t-table.


2018 ◽  
Vol 281 ◽  
pp. 230-235
Author(s):  
Wang Nian Zhang ◽  
Li Wang ◽  
Ni Deng

Micropowder MgCO3 was added into magnesite as raw materials to prepare magnesia using a two-step calcination method. The sample magnesite was characterized use X-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results showed that the sample insulated at 1600° C for 3 hours before and after sintering presented a linear change rate of 15.6 % in the case of without adding micropowder MgCO3, the prepared magnesia had a bulk density of 2.31 g/cm3 and apparent porosity of 32.8 %, while MgO grain size was 3.11 μm. In the case of adding 8 % micropowder MgCO3, the sample magnesite before and after sintering showed a linear change rate of 17.9 %. The bulk density, apparent porosity of prepared magnesia were 2.46 g/cm3 and 28.1 % respectively, while the grain size of MgO was 5.15 mm.


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